Tabela com principais espec.
|Key Applications||Detection Methods|
|ICC, IHC, IH(P), FC||Fluorescent|
|Safety Information according to GHS|
|Material Size||40 assays|
Referências | 39 Disponível | Ver todas as referências
|Visão geral das referências||Espécies||Pub Med ID|
|Activation of glial FGFRs is essential in glial migration, proliferation, and survival and in glia-neuron signaling during olfactory system development. |
Gibson, NJ; Tolbert, LP; Oland, LA
PloS one 7 e33828 2012
Development of the adult olfactory system of the moth Manduca sexta depends on reciprocal interactions between olfactory receptor neuron (ORN) axons growing in from the periphery and centrally-derived glial cells. Early-arriving ORN axons induce a subset of glial cells to proliferate and migrate to form an axon-sorting zone, in which later-arriving ORN axons will change their axonal neighbors and change their direction of outgrowth in order to travel with like axons to their target areas in the olfactory (antennal) lobe. These newly fasciculated axon bundles will terminate in protoglomeruli, the formation of which induces other glial cells to migrate to surround them. Glial cells do not migrate unless ORN axons are present, axons fail to fasciculate and target correctly without sufficient glial cells, and protoglomeruli are not maintained without a glial surround. We have shown previously that Epidermal Growth Factor receptors and the IgCAMs Neuroglian and Fasciclin II play a role in the ORN responses to glial cells. In the present work, we present evidence for the importance of glial Fibroblast Growth Factor receptors in glial migration, proliferation, and survival in this developing pathway. We also report changes in growth patterns of ORN axons and of the dendrites of olfactory (antennal lobe) neurons following blockade of glial FGFR activation that suggest that glial FGFR activation is important in reciprocal communication between neurons and glial cells.
|Acetylation of myocardin is required for the activation of cardiac and smooth muscle genes. |
Dongsun Cao,Chunbo Wang,Ruhang Tang,Huaqun Chen,Zheng Zhang,Mariko Tatsuguchi,Da-Zhi Wang
The Journal of biological chemistry 287 2012
Myocardin belongs to the SAF-A/B, Acinus, PIAS (SAP) domain family of transcription factors and is specifically expressed in cardiac and smooth muscle. Myocardin functions as a transcriptional coactivator of SRF and is sufficient and necessary for smooth muscle gene expression. We have previously found that myocardin induces the acetylation of nucleosomal histones surrounding SRF-binding sites in the control regions of cardiac and smooth muscle genes through recruiting chromatin-modifying enzyme p300, yet no studies have determined whether myocardin itself is similarly modified. In this study, we show that myocardin is a direct target for p300-mediated acetylation. p300 acetylates lysine residues at the N terminus of the myocardin protein. Interestingly, a direct interaction between p300 and myocardin, which is mediated by the C terminus of myocardin, is required for the acetylation event. Acetylation of myocardin by p300 enhances the association of myocardin and SRF as well as the formation of the myocardin-SRF-CArG box ternary complex. Conversely, acetylation of myocardin decreases the binding of histone deacetylase 5 (HDAC5) to myocardin. Acetylation of myocardin is required for myocardin to activate smooth muscle genes. Our study demonstrates that acetylation plays a key role in modulating myocardin function in controlling cardiac and smooth muscle gene expression.
|Binding of carbon nanotube to BMP receptor 2 enhances cell differentiation and inhibits apoptosis via regulating bHLH transcription factors. |
Y Zhang,Q Mu,H Zhou,K Vrijens,M F Roussel,G Jiang,B Yan
Cell death & disease 3 2012
Biomaterials that can drive stem cells to an appropriate differentiation level and decrease apoptosis of transplanted cells are needed in regenerative medicine. Nanomaterials are promising novel materials for such applications. Here we reported that carboxylated multiwalled carbon nanotube (MWCNT 1) promotes myogenic differentiation of mouse myoblast cells and inhibits cell apoptosis under the differentiation conditions by regulating basic helix-loop-helix transcription factors. MWCNT 1 attenuates bone morphogenetic protein receptor (BMPR) signaling activity by binding to BMPR2 and attenuating the phosphorylation of BMPR1. This molecular understanding allowed us to tune stem cell differentiation to various levels by chemical modifications, demonstrating human control of biological activities of nanoparticles and opening an avenue for potential applications of nanomaterials in regenerative medicine.
|Id2 controls chondrogenesis acting downstream of BMP signaling during maxillary morphogenesis. |
Tomoko Sakata-Goto,Katsu Takahashi,Honoka Kiso,Boyen Huang,Hiroko Tsukamoto,Mitsuru Takemoto,Tatsunari Hayashi,Manabu Sugai,Takashi Nakamura,Yoshifumi Yokota,Akira Shimizu,Harold Slavkin,Kazuhisa Bessho
Bone 50 2012
Maxillofacial dysmorphogenesis is found in 5% of the population. To begin to understand the mechanisms required for maxillofacial morphogenesis, we employed the inhibitors of the differentiation 2 (Id2) knock-out mouse model, in which Id proteins, members of the regulator of basic helix-loop-helix (bHLH) transcription factors, modulate cell proliferation, apoptosis, and differentiation. We now report that spatially-restricted growth defects are localized at the skull base of Id2 KO mice. Curiously, at birth, neither the mutant Id2 KO nor wild-type (WT) mice differed, based upon cephalometric and histological analyses of cranial base synchondroses. In postnatal week 2, a narrower hypertrophic zone and an inhibited proliferative zone in presphenoid synchondrosis (PSS) and spheno-occipital synchondrosis (SOS) with maxillary hypoplasia were identified in the Id2 mutant mice. Complementary studies revealed that exogenous bone morphogenetic proteins (BMPs) enhanced cartilage growth, matrix deposition, and chondrocyte proliferation in the WT but not in the mutant model. Id2-deficient chondrocytes expressed more Smad7 transcripts. Based on our results, we assert that Id2 plays an essential role, acting downstream of BMP signaling, to regulate cartilage formation at the postnatal stage by enhancing BMP signals through inhibiting Smad7 expression. As a consequence, abnormal endochondral ossification was observed in cranial base synchondroses during the postnatal growth period, resulting in the clinical phenotype of maxillofacial dysmorphogenesis.
|Sustained induction of neuronal addition to the adult rat neostriatum by AAV4-delivered noggin and BDNF. |
A Benraiss,E Bruel-Jungerman,G Lu,A N Economides,B Davidson,S A Goldman
Gene therapy 19 2012
Intraventricular ependymal infection by adenoviruses expressing brain-derived neurotrophic factor (BDNF) and noggin is sufficient to induce the heterotopic recruitment of new medium spiny neurons to the adult neostriatum, from endogenous subependymal neural progenitor cells. This approach was found to slow disease progression and extend survival in an R6/2 mouse model of Huntington's disease (HD). However, the practical therapeutic value of this strategy is limited by the transient expression and immunogenicity of adenoviral vectors. In addition, it has been unclear whether sustained overexpression of BDNF and noggin would yield similarly sustained neuronal production and striatal recruitment, or whether progenitor depletion or tachyphylaxis might supervene to limit the therapeutic potential of this approach. To address these issues, we used adeno-associated virus serotype 4 (AAV4), an ependymotrophic vector that is neither immunogenic nor neurotoxic, to achieve sustained BDNF and noggin expression. Using AAV4, we found that BDNF and noggin achieved levels sufficient to initiate and maintain, for at least 4 months, ongoing neuronal addition to the neostriatum and olfactory bulb. Over this period, we noted no diminution of treatment-associated neuronal recruitment from resident progenitors. AAV4:BDNF and noggin-induced neuronal addition may thus provide a means to provide longlasting and persistent striatal neuronal replacement in conditions of striatal neuronal loss, such as HD.
|Malignancy without immortality Cellular immortalization as a possible late event in melanoma progression. |
Soo JK, Mackenzie Ross AD, Kallenberg DM, Milagre C, Heung Chong W, Chow J, Hill L, Hoare S, Collinson RS, Hossain M, Keith WN, Marais R, Bennett DC
Pigment cell & melanoma research 24 490-503 2011
Cell senescence is a permanent growth arrest following extended proliferation. Cultured cancer cells including metastatic melanoma cells often appear immortal (proliferate indefinitely), while uncultured benign nevi (moles) show senescence markers. Here, with new explantation methods, we investigated which classes of primary pigmented lesions are typically immortal. Nevi yielded a few proliferating cells, consistent with most nevus cells being senescent. No nevus culture (0/28) appeared immortal. Some thin and thick melanoma cultures proved immortal under these conditions, but surprisingly few (4/37). All arrested cultures displayed three senescence markers in some cells: β-galactosidase, nuclear p16, and heterochromatic foci/aggregates. However, melanoma cultures also showed features of telomeric crisis (arrest because of ultrashort telomeres). Moreover, crisis markers including anaphase bridges were frequent in uncultured vertical growth-phase (VGP) melanomas. Conversely, all immortal melanoma cultures expressed telomerase reverse transcriptase and telomerase, showing aneuploidy. The findings suggest that primary melanomas are typically precrisis, with immortalization/telomere maintenance as a late event.
|Pentoxifylline improves nonalcoholic steatohepatitis: A randomized placebo-controlled trial. |
Zein CO, Yerian LM, Gogate P, Lopez R, Kirwan JP, Feldstein AE, McCullough AJ.
Hepatology (Baltimore, Md.) 54 1610-9 2011
The primary aim of this study was to compare the effects of pentoxifylline (PTX) versus placebo on the histological features of nonalcoholic steatohepatitis (NASH). In all, 55 adults with biopsy-confirmed NASH were randomized to receive PTX at a dose of 400 mg three times a day (n = 26) or placebo (n = 29) over 1 year. The primary efficacy endpoint was defined as improvement in histological features of NASH through reduction in steatosis, lobular inflammation, and/or hepatocellular ballooning as reflected by a decrease of ≥2 points in the nonalcoholic fatty liver disease (NAFLD) activity score (NAS). After 1 year, intention-to-treat analysis showed a decrease of ≥2 points in the NAS in 38.5% of patients on PTX versus 13.8% of those on placebo (P = 0.036). Per protocol analysis, a decrease of ≥2 points in the NAS from baseline was observed in 50% of the patients on PTX versus 15.4% of those on placebo (P = 0.01). The mean change in NAS score from baseline was -1.6 in the PTX group, versus -0.1 in the placebo group (P < 0.001). PTX significantly improved steatosis (mean change in score -0.9 versus -0.04 with placebo, P < 0.001) and lobular inflammation (median change -1 versus 0 with placebo, P = 0.02). No significant effects in hepatocellular ballooning were observed. PTX also improved liver fibrosis (mean change in fibrosis score was -0.2 among those on PTX versus +0.4 among those on placebo, P = 0.038). Although not statistically significant (P = 0.17), improvement in fibrosis was observed in a greater proportion (35%) of patients in the PTX group compared to placebo (15%). Adverse effects were similar in both groups. Conclusion: PTX improved histological features of NASH compared to placebo. PTX was well tolerated in patients with NASH (ClinicalTrials.gov number NCT00590161). (HEPATOLOGY 2011).
|Vascular rhexis in Mice subjected to non-sustained Myocardial ischemia and its therapeutic implications. |
Zaman AK, French CJ, Spees JL, Binbrek AS, Sobel BE
Experimental biology and medicine (Maywood, NJ) 236 598-603. Epub 2011 Apr 26. 2011
We previously described the death of vascular cells (vascular rhexis) following persistent coronary occlusion. The present study was designed to determine whether non-sustained ischemia can initiate vascular rhexis and if so, whether relatively brief ischemic insults are sufficient. C57BL6 mice were subjected to coronary ligation for 15 min or 3 h followed by reperfusion. Soluble fractions of left ventricular (LV) homogenates were obtained 48 h after the onset of transitory coronary occlusion. They were assayed by Western blotting for quantification of alpha smooth muscle actin (α-SMA) and smooth muscle myosin heavy chain (SM-MHC) that we have shown reflect vascular rhexis delineated immunohistochemically. Non-sustained coronary occlusion for 3 h initiated vascular rhexis evident 45 h after reperfusion, but not earlier, as judged from Western blotting of α-SMA and SM-MHC. The number of small- and medium-sized vessels in the previously ischemic zones was reduced at 45 h after reperfusion as well. Thus, vascular rhexis occurs after ischemia as brief as 3 h but evolves slowly and is not evident for 45 h. The delayed disintegration of the vasculature makes it likely that it can be ameliorated by interventions initiated after non-sustained ischemia, rendering it an attractive target for diminution of phenomena such as late negative LV remodeling, and \'no reflow.\'
|Labedipinedilol-A prevents lysophosphatidylcholine-induced vascular smooth Muscle cell death through reducing reactive oxygen species production and anti-apoptosis. |
Hsu JH, Wu JR, Liou SF, Chen HM, Dai ZK, Chen IJ, Yeh JL
|Effect of hypothermia on doxorubicin-induced cardiac Myoblast signaling and cell death. |
L\'ecuyer TJ, Aggarwal S, Zhang JP, Van der Heide RS
Cardiovascular pathology : the official journal of the Society for Cardiovascular Pathology 2011
|Strategy for increasing drug solubility and efficacy through covalent attachment to polyvalent DNA-nanoparticle conjugates. |
Xue-Qing Zhang,Xiaoyang Xu,Robert Lam,David Giljohann,Dean Ho,Chad A Mirkin
ACS nano 5 2011
Paclitaxel, a potent chemotherapeutic utilized in a variety of cancers, can be limited in its effectiveness due to inherent insolubility in aqueous media and acquired chemoresistance within certain cells. An approach has been developed for increasing Paclitaxel solubility and effectiveness by covalent attachment to gold nanoparticles via DNA linkers. The resulting conjugates are highly soluble in aqueous buffer, exhibiting greater than a 50-fold increase in solubility over the unconjugated drug. DNA linkers are labeled with a fluorophore, which affords a convenient means of visualizing resultant conjugates within cells. Internalized conjugates demonstrate increased activity as compared with free drug across a variety of cell types, including a Paclitaxel-resistant cell line. Attachment to DNA-nanoparticle conjugates may become a general strategy for solubilizing and enhancing a wide variety of therapeutic agents in aqueous media.
|A src family kinase inhibitor improves survival in experimental acute liver failure associated with elevated cerebral and circulating vascular endothelial growth factor levels. |
Aspinall RJ, Weis SM, Barnes L, Lutu-Fuga K, Bylund DJ, Pockros PJ, Cheresh DA
Liver international : official journal of the International Association for the Study of the Liver 2011
Background and aims: Acute liver failure (ALF) is frequently complicated by cerebral oedema, systemic inflammation and multiorgan dysfunction. Vascular endothelial growth factor (VEGF) may stimulate liver regeneration but it can also be pro-inflammatory, activating endothelial cells and increasing permeability, actions mediated through Src kinase signalling. We therefore examined whether a Src inhibitor could have therapeutic potential in ALF. Methods: Murine ALF was induced with azoxymethane. Liver pathology was graded by a blinded examiner and apoptosis quantified by immunohistochemistry. Cerebral VEGF expression was imaged using VEGF-green fluorescent protein transgenic mice. Circulating and macrophage-secreted VEGF levels were measured. Experimental animals received a Src inhibitor or vehicle controls. Results: VEGF was undetectable in normal plasma but reached a mean of 835 pg/ml at grade III encephalopathy (P<0.001). Ammonia, lipopolysaccharide and interferon-gamma acted synergistically to enhance VEGF secretion by macrophages. Production of VEGF by cerebral cortical astrocytes increased with disease progression. Late treatment with inhibitors of Src or VEGF did not improve liver histology, encephalopathy or survival. However, early use of a Src kinase inhibitor significantly reduced hepatic injury, delayed encephalopathy and allowed 25% of mice to survive an otherwise lethal insult. Conclusion: Systemic and cerebral VEGF levels are significantly elevated during experimental ALF and may be exacerbated by hyperammonemia and macrophage activation. Early use of a Src inhibitor reduced hepatocellular injury and enabled survival, indicating such agents may have some promise in the treatment of ALF.© 2011 John Wiley & Sons A/S.
|Hypoxia-induced expression of vEGF in the organotypic spinal cord slice culture. |
An SS, Pennant WA, Ha Y, Oh JS, Kim HJ, Gwak SJ, Yoon do H, Kim KN
Neuroreport 22 55-60. 2011
We used the erythropoietin enhancer and Simian virus-40 promoter to create a hypoxia-inducible gene expression system to investigate the effect of vascular endothelial growth factor (VEGF) gene therapy on neuroprotection and neurogenesis in organotypic spinal cord slice culture. The organotypic spinal cord slice culture transfected with pEpo-SV-VEGF expressed the highest amount of VEGF under hypoxic conditions and showed decreased apoptosis and increased proliferation, and evidence of neurogenesis. Our results show that the hypoxia-induced VEGF expression in an organotypic spinal cord slice culture may lead to an optimal treatment for spinal cord injury.
|Thermosensitive chitosan-gelatin-glycerol phosphate hydrogel as a controlled release system of ferulic acid for nucleus pulposus regeneration. |
Yung-Hsin Cheng,Shu-Hua Yang,Feng-Huei Lin
Biomaterials 32 2011
In the degenerative disc, overproduction of reactive oxygen species (ROS) involves in apoptosis and senescence of nucleus pulposus (NP) cells that could accelerate the degenerative process. Ferulic acid (FA) has been reported to have an excellent antioxidant property. In the study, injectable thermosensitive chitosan/gelatin/glycerol phosphate (C/G/GP) hydrogel was applied as a controlled release system for FA delivery. The study was aimed to evaluate possible therapeutic effects of FA-incorporated C/G/GP hydrogel on hydrogen peroxide (H(2)O(2))-induced oxidative stress NP cells. The results showed that the release of FA from C/G/GP hydrogel could decrease the H(2)O(2)-induced oxidative stress. Post-treatment of FA-incorporated C/G/GP hydrogel on H(2)O(2)-induced oxidative stress NP cells showed up-regulation of Aggrecan and type II collagen and down-regulation of MMP-3 in mRNA level. The results of sulfated-glycosaminoglycans (GAGs) to DNA ratio and alcian blue staining revealed that the GAGs production of H(2)O(2)-induced oxidative stress NP cells could reach to normal level. The results of caspase-3 activity and TUNEL staining indicated that FA-incorporated C/G/GP hydrogel decreased the apoptosis of H(2)O(2)-induced oxidative stress NP cells. The results suggested that the C/G/GP hydrogel was very suitable for sustained delivery of FA. The FA-incorporated C/G/GP hydrogel would be used to treat the degenerative disc in the early stage before it developed into the latter irreversible stages.
|Abnormal embryonic lymphatic vessel development in Tie1 hypomorphic mice. |
Xianghu Qu,Kevin Tompkins,Lorene E Batts,Mira Puri,Scott Baldwin
Development (Cambridge, England) 137 2010
Tie1 is an endothelial receptor tyrosine kinase that is essential for development and maintenance of the vascular system; however, the role of Tie1 in development of the lymphatic vasculature is unknown. To address this question, we first documented that Tie1 is expressed at the earliest stages of lymphangiogenesis in Prox1-positive venous lymphatic endothelial cell (LEC) progenitors. LEC Tie1 expression is maintained throughout embryonic development and persists in postnatal mice. We then generated two lines of Tie1 mutant mice: a hypomorphic allele, which has reduced expression of Tie1, and a conditional allele. Reduction of Tie1 levels resulted in abnormal lymphatic patterning and in dilated and disorganized lymphatic vessels in all tissues examined and in impaired lymphatic drainage in embryonic skin. Homozygous hypomorphic mice also exhibited abnormally dilated jugular lymphatic vessels due to increased production of Prox1-positive LECs during initial lymphangiogenesis, indicating that Tie1 is required for the early stages of normal lymphangiogenesis. During later stages of lymphatic development, we observed an increase in LEC apoptosis in the hypomorphic embryos after mid-gestation that was associated with abnormal regression of the lymphatic vasculature. Therefore, Tie1 is required for early LEC proliferation and subsequent survival of developing LECs. The severity of the phenotypes observed correlated with the expression levels of Tie1, confirming a dosage dependence for Tie1 in LEC integrity and survival. No defects were observed in the arterial or venous vasculature. These results suggest that the developing lymphatic vasculature is particularly sensitive to alterations in Tie1 expression.Texto completo do artigo
|Analysis of a Hand1 hypomorphic allele reveals a critical threshold for embryonic viability. |
Firulli BA, McConville DP, Byers JS 3rd, Vincentz JW, Barnes RM, Firulli AB
Dev Dyn 239 2748-60. 2010
Loss-of-function analysis of the basic helix-loop-helix (bHLH) transcription factor Hand1 indicates critical roles in development. In an effort to generate a Hand1 cDNA knock-in reporter mouse, we generated two hypomorphic alleles, which extend embryonic survival to between embryonic day (E) 10.5 and E12.5. Heart morphogenesis appears largely normal; however, hypomorphic mice display thin left ventricular myocardium and reduction in pharyngeal mesoderm. Caudal defects, large allantois, and thickened yolk sac are observed and consistent with systemic Hand1 gene deletion. Hand1 mRNA is expressed at 30% of wild-type littermates and known Hand1-dependent genes show intermediate expression compared with wild-type and Hand1 null mice. Interestingly, putative bHLH partners, Hand2 and Twist1, show altered expression in both Hand1 null and hypomorphic backgrounds and intercrossing the Hand1 hypomorphic mice onto the Hand2 systemic null background exacerbates the cardiac and lateral mesoderm phenotypes. Together, these data define a critical threshold of Hand1 expression that is necessary for embryonic survival.Texto completo do artigo
|Vascular rhexis: loss of integrity of coronary vasculature in mice subjected to myocardial infarction. |
French CJ, Zaman AK, Kelm RJ Jr, Spees JL, Sobel BE
Exp Biol Med (Maywood) 235 966-73. 2010
We previously observed gross hemorrhage in plasminogen activator inhibitor type-1 (PAI-1) knockout (PKO) mice with induced myocardial infarction (MI). We hypothesized that it reflected degradation of vessels - a phenomenon we termed vascular rhexis. Accordingly, in the present study we characterized vascular rhexis in C57BL6 mice. MI was induced in 10- to 12-week-old mice by coronary artery ligation for 24, 48, 72 or 96 h. Hemorrhage was quantified by non-cross-reacting enzyme-linked immunosorbent assay of left ventricular (LV) hemoglobin corrected for myoglobin. Degradation of vasculature was quantified by the appearance of alpha smooth muscle actin (alphaSMA) in low salt soluble fractions of LV homogenates (Western blotting) and by immunohistochemistry (residual alphaSMA). Co-staining for CD31 (endothelial cells) and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) (a marker of cell death) was used to identify capillary rhexis. PKO mice (n = 9) had marked hemorrhage in infarct zones (432 +/- 27 standard error of mean microL blood/g). Hemorrhage was evident in C57BL6 mice as well (n = 6): 51 +/- 8 microL/g LV 96 h after coronary occlusion compared with 10 +/- 5 microL /g, n = 13 in normal LVs. Residual intact vasculature was reduced 48 h after infarction. Thus, an average of 16 +/- 1.6 small- and medium-sized vessels (n = 5 hearts) were seen compared with 84 +/- 4.8 in normal LVs (n = 3, P < or = 0.05). An approximately three-fold increase in soluble alphaSMA 48 h after MI (2.68 +/- 0.28, n = 6) was seen relative to that in normal LVs defined as 1.0 +/- 0.04, n = 10, P < or = 0.05. Capillary degradation was evident as well, as judged from CD31 and TUNEL co-localization. Vascular rhexis occurs within 48 h after the onset of MI. It may contribute to the early no-reflow phenomenon and to late negative LV remodeling.
|Dietary docosahexaenoic acid supplementation modulates hippocampal development in the Pemt-/- mouse. |
da Costa KA, Rai KS, Craciunescu CN, Parikh K, Mehedint MG, Sanders LM, McLean-Pottinger A, Zeisel SH
The Journal of biological chemistry 285 1008-15 2010
The development of fetal brain is influenced by nutrients such as docosahexaenoic acid (DHA, 22:6) and choline. Phosphatidylethanolamine-N-methyltransferase (PEMT) catalyzes the biosynthesis of phosphatidylcholine from phosphatidylethanolamine enriched in DHA and many humans have functional genetic polymorphisms in the PEMT gene. Previously, it was reported that Pemt(-/-) mice have altered hippocampal development. The present study explores whether abnormal phosphatidylcholine biosynthesis causes altered incorporation of DHA into membranes, thereby influencing brain development, and determines whether supplemental dietary DHA can reverse some of these changes. Pregnant C57BL/6 wild type (WT) and Pemt(-/-) mice were fed a control diet, or a diet supplemented with 3 g/kg of DHA, from gestational day 11 to 17. Brains from embryonic day 17 fetuses derived from Pemt(-/-) dams fed the control diet had 25-50% less phospholipid-DHA as compared with WT (p < 0.05). Also, they had 60% more neural progenitor cell proliferation (p < 0.05), 60% more neuronal apoptosis (p < 0.01), and 30% less calretinin expression (p < 0.05; a marker of neuronal differentiation) in the hippocampus compared with WT. The DHA-supplemented diet increased fetal brain Pemt(-/-) phospholipid-DHA to WT levels, and abrogated the neural progenitor cell proliferation and apoptosis differences. Although this diet did not change proliferation in the WT group, it halved the rate of apoptosis (p < 0.05). In both genotypes, the DHA-supplemented diet increased calretinin expression 2-fold (p < 0.05). These results suggest that the changes in hippocampal development in the Pemt(-/-) mouse could be mediated by altered DHA incorporation into membrane phospholipids, and that maternal dietary DHA can influence fetal brain development.Texto completo do artigo
|Complement and alcoholic liver disease: role of C1q in the pathogenesis of ethanol-induced liver injury in mice. |
Cohen JI, Roychowdhury S, McMullen MR, Stavitsky AB, Nagy LE
Gastroenterology 139 664-74, 674.e1. Epub 2010 Apr 21. 2010
BACKGROUND & AIMS: Complement is involved in the development of alcoholic liver disease in mice; however, the mechanisms for complement activation during ethanol exposure have not been identified. C1q, the recognition subunit of the first complement component, binds to apoptotic cells, thereby activating the classical complement pathway. Because ethanol exposure increases hepatocellular apoptosis, we hypothesized that ethanol-induced apoptosis would lead to activation of complement via the classical pathway.
|Gonadotropin stimulation as a challenge to calibrate cisplatin induced ovarian damage in the female rat. |
J Yeh, BS Kim, YJ Liang, J Peresie
Reproductive toxicology (Elmsford, N.Y.) 28 556-62 2009
Cisplatin administration for treatment of cancer causes damage to the ovaries, potentially leading to ovarian failure. To extend our previous work, we tested the hypothesis that serum anti-Mullerian hormone (AMH) levels after ovarian stimulation can be used as a biomarker to calibrate the degree of ovarian damage following cisplatin. Female rats were injected with two weekly doses of cisplatin followed by an injection of pregnant mare serum gonadotropin to stimulate the ovaries. Sera and ovaries were collected 54 h after gonadotropin challenge. Analysis of serum and ovarian AMH by Western blot and ELISA revealed that increasing doses of cisplatin caused dose-dependent decrease in AMH after gonadotropin stimulation. Immunohistochemical analysis demonstrated that the AMH positive follicles declined in a dose-dependent manner after cisplatin, resulting in AMH levels that are lower after cisplatin exposure. Cisplatin damage to the ovaries can be identified by the serum AMH levels following exogenous ovarian stimulation.
|Protein kinase Cepsilon inhibits UVR-induced expression of FADD, an adaptor protein, linked to both Fas- and TNFR1-mediated apoptosis. |
Aziz MH, Sundling KE, Dreckschmidt NE, Verma AK
J Invest Dermatol 129 2011-21. Epub 2009 Feb 5. 2009
Protein kinase C (PKC)epsilon overexpression in FVB/N transgenic mice sensitized skin to UVR-induced development of squamous cell carcinomas and suppressed formation of sunburn cells, which are DNA-damaged keratinocytes undergoing apoptosis. Here, we elucidated the mechanisms associated with the inhibition of UVR-induced appearance of sunburn cells in PKCepsilon transgenic mice. We found that the inhibition of UVR-induced sunburn cell formation in PKCepsilon transgenic mice may be the result of the inhibition of the expression of Fas, Fas ligand, and the mammalian death adaptor protein termed Fas-associated with death domain (FADD). The adaptor protein FADD is the key component of the death-inducing signaling complex of both Fas and tumor necrosis factor receptor 1. A decreased expression of epidermal FADD was observed after a single UVR exposure. However, a complete loss of FADD expression was found after four (Monday, Wednesday, Friday, and Monday) repeated UVR exposures. FADD transmits apoptotic signals from death receptors to the downstream initiator caspase-8 and connects to the mitochondrial intrinsic apoptotic signal transduction pathway by the cleavage of Bid, a Bcl-2 family member. PKCepsilon-mediated loss of FADD expression inhibited UVR signals to the activation of both extrinsic and intrinsic apoptotic pathways.Texto completo do artigo
|Conditional deletion of the retinoblastoma (Rb) gene in ovarian granulosa cells leads to premature ovarian failure. |
Claudia Andreu-Vieyra, Ruihong Chen, Martin M Matzuk
Molecular endocrinology (Baltimore, Md.) 22 2141-61 2008
The retinoblastoma protein (RB) regulates cell proliferation and survival by binding to the E2F family of transcription factors. Recent studies suggest that RB also regulates differentiation in a variety of cell types, including myocytes, neurons, adipocytes, and chondrocytes. Rb mutations have been found in ovarian cancer; however, the role of RB in normal and abnormal ovarian function remains unclear. To test the hypothesis that loss of Rb induces ovarian tumorigenesis, we generated an ovarian granulosa cell conditional knockout of Rb (Rb cKO) using the Cre/lox recombination system. Rb cKO females showed 100% survival and no ovarian tumor formation through 9 months of age, but they developed progressive infertility. Prepubertal Rb cKO females showed increased ovulation rates compared with controls, correlating with increased follicle recruitment, higher Fshr and Kitl mRNA levels, and lower anti-Müllerian hormone levels. In contrast, the ovulation rate of 6-wk-old females was similar to that of controls. Morphometric analysis of Rb cKO ovaries from 6-wk-old and older females showed increased follicular atresia and apoptosis. Rb cKO ovaries and preantral follicles had abnormal levels of known direct and indirect target genes of RB, including Rbl2/p130, E2f1, Ccne2, Myc, Fos, and Tgfb2. In addition, preantral follicles showed increased expression of the granulosa cell differentiation marker Inha, decreased levels of Foxl2 and Cyp19a1 aromatase, and abnormal expression of the nuclear receptors Nr5a1, Nr5a2, and Nr0b1. Taken together, our results suggest that RB is required for the temporal-specific pattern of expression of key genes involved in follicular development.Texto completo do artigo
|Tissue-type plasminogen activator and the low-density lipoprotein receptor-related protein induce Akt phosphorylation in the ischemic brain. |
Jie An, Chen Zhang, Rohini Polavarapu, Xiaohui Zhang, Xiumei Zhang, Manuel Yepes
Blood 112 2787-94 2008
Tissue-type plasminogen activator (tPA) is found in the intravascular space and in the central nervous system. The low-density lipoprotein receptor-related protein (LRP) is expressed in neurons and in perivascular astrocytes. During cerebral ischemia, tPA induces the shedding of LRP's extracellular domain from perivascular astrocytes, and this is followed by the development of cerebral edema. Protein kinase B (Akt) is a serine/threonine kinase that plays a critical role not only in cell survival but also in the regulation of the permeability of the blood-brain barrier. We found that, in the early phases of the ischemic insult, the interaction between tPA and LRP induces Akt phosphorylation (pAkt) in perivascular astrocytes and inhibits pAkt in neurons. Coimmunoprecipitation studies indicate that pAkt and LRP's intracellular domain interact in perivascular astrocytes and that this interaction is dependent on the presence of tPA and results in the development of edema. Together, these results indicate that, in the early stages of cerebral ischemia, the interaction between tPA and LRP in perivascular astrocytes induces the activation of a cell signaling event mediated by pAkt that leads to increase in the permeability of the blood-brain barrier.Texto completo do artigo
|Baseline and stimulated serum inhibin levels as biomarkers of cisplatin-induced ovarian damage in female rats. |
John Yeh,Beom Su Kim,Yuan Jing Liang,Jennifer Peresie
American journal of obstetrics and gynecology 198 2008
Chemotherapeutic agents, such as cisplatin, injure the ovary. It was hypothesized that serum inhibins can serve as biomarkers of ovarian damage from cisplatin.
|Protection against cisplatin-induced ovarian damage by the antioxidant sodium 2-mercaptoethanesulfonate (mesna) in female rats. |
John Yeh, Beom Su Kim, Jennifer Peresie
American journal of obstetrics and gynecology 198 463.e1-6; discussion 463.e6-7 2008
OBJECTIVE: The hypothesis was that the administration of the antioxidant mesna (sodium 2-mercaptoethanesulfonate) during chemotherapy would protect ovaries against follicular damage. STUDY DESIGN: Sprague-Dawley rats were treated with saline solution, mesna-plus-cisplatin, or cisplatin. Immunohistochemistry was used to evaluate the Müllerian inhibiting substance (MIS) positive follicles. Serum and ovarian MIS were measured with enzyme-linked immunosorbent assay and Western blot analysis, respectively. Apoptosis in ovaries was studied by terminal deoxynucleotidyl transfer biotin-d UTP nick end labeling (TUNEL) assay. RESULT: Immunofluorescence staining for MIS was higher in preantral follicles in the mesna-plus-cisplatin group. The ovarian and serum MIS levels were higher in the mesna-plus-cisplatin than in the cisplatin alone group. There were no differences statistically in the TUNEL and the ovarian cyst analyses. CONCLUSION: Mesna, which was used at the time of cisplatin administration, protected ovaries against damage. The data that are presented challenge the existing clinical paradigm that gonadotropin-releasing hormone agonists represent the only medical method for the protection of ovaries during chemotherapy. Alternative medical means to protect ovaries during chemotherapy may be achievable.
|Effects of granulosa cell-specific deletion of Rb in Inha-alpha null female mice. |
Andreu-Vieyra, C; Chen, R; Matzuk, MM
Endocrinology 148 3837-49 2007
Our laboratory is interested in the gonadal growth regulatory properties of inhibins, members of the TGFbeta superfamily. We have previously shown that female mice lacking inhibins (Inha(-/-)) develop granulosa cell tumors and that concurrent loss of p27 accelerates tumor development. It has also been shown that the retinoblastoma protein RB regulates the G(1) to S phase transition of the cell cycle by controlling the activity of transcription factors and stabilizing the levels of the cell cycle inhibitor P27. Based on these data, we hypothesized that concurrent loss of Rb and inhibins in the ovary will exacerbate tumor formation. To test this hypothesis, we generated an ovarian granulosa cell conditional knockout (cKO) of Rb using the Cre/lox recombination system in the background of Inha(-/-) mice. Inha(-/-)/Rb cKO females show a modest increase in mortality rates compared with Inha(-/-) females. Although histologically similar to Inha(-/-) ovarian tumors, tumors from Inha(-/-)/Rb cKO females show increased number of mitotic figures and apoptotic rates. Interestingly, P27 levels are decreased in Inha(-/-)/Rb cKO ovarian tumors, likely due to the combined effect of Rb loss and increased Skp2 expression, which targets P27 to the proteosome. We propose that Rb loss may cause cell cycle delay or arrest, followed by apoptosis and that increases in p107 and p130 levels may compensate for Rb loss. These findings confirm the importance of P27 as a cell cycle regulator in granulosa cells and suggest functional compensation between RB-like proteins in ovarian tumorigenesis.
|Analysis of apoptosome dysregulation in pancreatic cancer and of its role in chemoresistance. |
Marco Corvaro,Claudia Fuoco,Martin Wagner,Francesco Cecconi
Cancer biology & therapy 6 2007
The apoptosome is a multiprotein complex mediating the mitochondrial pathway of cell death. Its importance during development has been clearly demonstrated by knocking out key genes in mouse. APAF1 is the core protein of the apoptosome and its dosage is also critical in various cancer types, i.e., melanoma, germ line tumor, gastrointestinal cancer and B-type chronic lymphocytic leukemia. This is generally due to inactivation of the APAF1 locus by epigenetic phenomena or by activity of promoter regulators. We investigated the putative roles of the apoptosome in pancreatic ductal adenocarcinoma (PDAC). We found that both APAF1 mRNA and protein are dysregulated in human PDAC samples. Similarly, several PDAC cell lines exhibited variable levels of both APAF1 protein and mRNA. The response to cell death induction and its biochemical features were assessed by treatment of each line with commonly used chemotherapeutic agents. We found that the apoptosome pathway was not functional in most cell lines upon cytochrome c release from mitochondria. In addition, we restored APAF1 and Caspase-9 dosage in Panc-1 cells, where the apoptosome is downregulated, by overexpressing the murine cDNA of the two molecules, and we improved the death response to chemotherapeutic agents.
|A germ line mutation in the death domain of DAPK-1 inactivates ERK-induced apoptosis. |
Craig Stevens, Yao Lin, Maria Sanchez, Eliana Amin, Ellen Copson, Helen White, Vicky Durston, Diana M Eccles, Ted Hupp
The Journal of biological chemistry 282 13791-803 2007
p53 is activated genetically by a set of kinases that are components of the calcium calmodulin kinase superfamily, including CHK2, AMP kinase, and DAPK-1. In dissecting the mechanism of DAPK-1 control, a novel mutation (N1347S) was identified in the death domain of DAPK-1. The N1347S mutation prevented the death domain module binding stably to ERK in vitro and in vivo. Gel filtration demonstrated that the N1347S mutation disrupted the higher order oligomeric nature of the purified recombinant death domain miniprotein. Accordingly, the N1347S death domain module is defective in vivo in the formation of high molecular weight oligomeric intermediates after cross-linking with ethylene glycol bis(succinimidylsuccinate). Full-length DAPK-1 protein harboring a N1347S mutation in the death domain was also defective in binding to ERK in cells and was defective in formation of an ethylene glycol bis(succinimidylsuccinate)-cross-linked intermediate in vivo. Full-length DAPK-1 encoding the N1347S mutation was attenuated in tumor necrosis factor receptor-induced apoptosis. However, the N1347S mutation strikingly prevented ERK:DAPK-1-dependent apoptosis as defined by poly(ADP-ribose) polymerase cleavage, Annexin V staining, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling imaging. Significant penetrance of the N1347S allele was identified in normal genomic DNA indicating the mutation is germ line, not tumor derived. The frequency observed in genomic DNA was from 37 to 45% for homozygous wild-type, 41 to 47% for heterozygotes, and 12 to 15% for homozygous mutant. These data highlight a naturally occurring DAPK-1 mutation that alters the oligomeric structure of the death domain, de-stabilizes DAPK-1 binding to ERK, and prevents ERK:DAPK-1-dependent apoptosis.
|Enhanced proapoptotic effects of tumor necrosis factor-related apoptosis-inducing ligand on temozolomide-resistant glioma cells. |
Mahmud Uzzaman, Gordon Keller, Isabelle M Germano
Journal of neurosurgery 106 646-51 2007
OBJECT: Death receptor targeting is an attractive approach in experimental treatment for tumors such as malignant gliomas, which are resistant to radiation and chemotherapy. Among the family of cytokines referred to as death li gands, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has attracted clinical interest. The aim of this study was to assess whether TRAIL can be used as an adjuvant to temozolomide (TMZ) for apoptosis induction in malignant glioma cell lines. METHODS: Six human malignant glioma cell lines (A172, U87, U251, T98, U343, and U373) were exposed to human (h)TRAIL, TMZ, or an hTRAIL/TMZ combined treatment. Cell viability was assayed using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide and phase-contrast microscopy. Cell apoptosis was detected using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling technique and quantified using flow cytometric analysis. The apoptosis signaling cascade was studied with Western blotting. The additive effects of hTRAIL and TMZ resulted in a significant decrease in cell viability and an increased apoptotic rate. Expression of the death receptors DR5 and DR4 in two cell lines (A172 and U251) upregulated significantly when they were used in combination hTRAIL/TMZ treatment (p 0.05 compared with baseline control), leading to activation of caspase-8 and caspase-3 (p 0.05 compared with baseline control) and confirming an extrinsic apoptotic pathway. A cell intrinsic pathway through mitochondrial cytochrome c was not activated. CONCLUSIONS: Based on this work, one may infer that hTRAIL should be considered as an adjuvant treatment for TMZ-resistant human malignant gliomas.
|Foxa2 controls vesicle docking and insulin secretion in mature Beta cells. |
Nan Gao, Peter White, Nicolai Doliba, Maria L Golson, Franz M Matschinsky, Klaus H Kaestner
Cell metabolism 6 267-79 2007
The winged-helix transcription factor Foxa2 regulates Pdx1 gene expression and fetal endocrine pancreas development. We show here by inducible gene ablation that Foxa2 inactivation in mature beta cells induces hyperinsulinemic hypoglycemia in Foxa2(loxP/loxP),Pdx1-CreERT2 adult mice. Mutant beta cells exhibited a markedly increased pool of docked insulin granules, some of which were engaged in sequential or compound exocytosis, consistent with increased first-phase glucose-stimulated insulin secretion. Expression of multiple genes involved in vesicular trafficking, membrane targeting, and fuel-secretion pathways is dependent on Foxa2. In addition, impaired cytosolic Ca(2+) oscillations and elevated intracellular cyclic AMP production accompanied this secretory defect and were likely contributors to the sensitization of the exocytotic machinery. Thus, in the absence of Foxa2, alterations in intracellular second-messenger signaling redistribute the insulin granules into the readily releasable pool. We conclude that Foxa2 is required for both fetal pancreas development and the function of mature beta cells.
|Identification of a dominant negative functional domain on DAPK-1 that degrades DAPK-1 protein and stimulates TNFR-1-mediated apoptosis. |
Yao Lin, Craig Stevens, Ted Hupp
The Journal of biological chemistry 282 16792-802 2007
DAPK-1 is a stress-activated tumor suppressor protein that plays a role in both proapoptotic or antiapoptotic signal transduction pathways. To define mechanisms of DAPK-1 protein regulation, we have determined that DAPK-1 protein has a long half-life, and therefore its activity is primarily regulated at the protein level. Changes in DAPK-1 protein levels occur by a cathepsin B-dependent pathway, prompting us to evaluate whether cathepsin B plays positive or negative role in DAPK-1 function. The transfection of p55-TNFR-1 induced complex formation between DAPK-1 and cathepsin B. Depletion of cathepsin B protein using small interfering RNA stimulated TNFR-1 dependent apoptosis. The minimal binding region on DAPK-1 for cathepsin B was mapped to amino acids 836-947. The transfection of the DAPK-1-(836-947) miniprotein acted in a dominant negative manner inducing endogenous DAPK-1 protein degradation in a TNFR-1-dependent manner. These data suggest that DAPK-1 forms a multiprotein survival complex with cathepsin B countering the rate of TNFR-1-dependent apoptosis and highlights the importance of developing DAPK-1 inhibitors as agents to sensitize cells to stress-induced apoptosis.
|Photodynamic molecular beacon as an activatable photosensitizer based on protease-controlled singlet oxygen quenching and activation. |
Gang Zheng, Juan Chen, Klara Stefflova, Mark Jarvi, Hui Li, Brian C Wilson
Proceedings of the National Academy of Sciences of the United States of America 104 8989-94 2007
Molecular beacons are FRET-based target-activatable probes. They offer control of fluorescence emission in response to specific cancer targets, thus are useful tools for in vivo cancer imaging. Photodynamic therapy (PDT) is a cell-killing process by light activation of a photosensitizer (PS) in the presence of oxygen. The key cytotoxic agent is singlet oxygen ((1)O(2)). By combining these two principles (FRET and PDT), we have introduced a concept of photodynamic molecular beacons (PMB) for controlling the PS's ability to generate (1)O(2) and, ultimately, for controlling its PDT activity. The PMB comprises a disease-specific linker, a PS, and a (1)O(2) quencher, so that the PS's photoactivity is silenced until the linker interacts with a target molecule, such as a tumor-associated protease. Here, we report the full implementation of this concept by synthesizing a matrix metalloproteinase-7 (MMP7)-triggered PMB and achieving not only MMP7-triggered production of (1)O(2) in solution but also MMP7-mediated photodynamic cytotoxicity in cancer cells. Preliminary in vivo studies also reveal the MMP7-activated PDT efficacy of this PMB. This study validates the core principle of the PMB concept that selective PDT-induced cell death can be achieved by exerting precise control of the PS's ability to produce (1)O(2) by responding to specific cancer-associated biomarkers. Thus, PDT selectivity will no longer depend solely on how selectively the PS can be delivered to cancer cells. Rather, it will depend on how selective a biomarker is to cancer cells, and how selective the interaction of PMB is to this biomarker.Texto completo do artigo
|Müllerian inhibiting substance as a novel biomarker of cisplatin-induced ovarian damage. |
John Yeh, Beomsu Kim, Yuan Jing Liang, Jennifer Peresie
Biochemical and biophysical research communications 348 337-44 2006
Müllerian inhibiting substance (MIS) has been investigated as a possible serum biomarker in human aging to estimate the number of female germ cells remaining. Cisplatin is an effective chemotherapeutic agent that is associated with ovarian injury. In this study, we tested the hypothesis that decreasing serum MIS can serve as a biomarker of ovarian damage after cisplatin. Adult female rats were treated with saline, 4.5, or 6.0 mg/kg cisplatin. The serum MIS levels were lower in both cisplatin groups, in a dose-related fashion. The ovarian lysates of both cisplatin groups had less MIS than control. Immunofluorescence analysis showed that the percentage of MIS-positive follicles was lower in the 6.0 mg/kg group. TUNEL assays showed that there was a dose related increase in the number of apoptotic follicles in the cisplatin groups. In summary, a decrease in serum MIS could serve as a biomarker to discriminate the degree of ovarian damage after cisplatin. These data are the first to establish in the rat that ovarian injury due to a chemotherapeutic agent could be monitored with the non-invasive serum biomarker MIS.
|Loss of neurons from laminas I-III of the spinal dorsal horn is not required for development of tactile allodynia in the spared nerve injury model of neuropathic pain. |
Erika Polgár, David I Hughes, Ahmad Z Arham, Andrew J Todd
The Journal of neuroscience : the official journal of the Society for Neuroscience 25 6658-66 2005
It has been proposed that death of inhibitory interneurons in the dorsal horn contributes to the neuropathic pain that follows partial nerve injury. In this study, we have used two approaches to test whether there is neuronal death in the dorsal horn in the spared nerve injury (SNI) model. We performed a stereological analysis of the packing density of neurons in laminas I-III 4 weeks after operation and found no reduction on the ipsilateral side compared with that seen on the contralateral side or in sham-operated or naive rats. In addition, we used two markers of apoptosis, terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL) staining and immunocytochemical detection of cleaved (activated) caspase-3. Neither of these methods demonstrated apoptotic neurons in the dorsal spinal cord 1 week after operation. Although TUNEL-positive cells were present throughout the gray and white matter at this stage, they were virtually all labeled with antibody against ionized calcium-binding adapter molecule 1, a marker for microglia. All animals that underwent SNI showed clear signs of tactile allodynia affecting the ipsilateral hindpaw. These results suggest that a significant loss of neurons from the dorsal horn is not necessary for the development of tactile allodynia in the SNI model.
|Single small-interfering RNA expression vector for silencing multiple transforming growth factor-beta pathway components. |
Amarsanaa Jazag, Fumihiko Kanai, Hideaki Ijichi, Keisuke Tateishi, Tsuneo Ikenoue, Yasuo Tanaka, Miki Ohta, Jun Imamura, Bayasi Guleng, Yoshinari Asaoka, Takao Kawabe, Makoto Miyagishi, Kazunari Taira, Masao Omata
Nucleic acids research 33 e131 2005
Although RNA interference (RNAi) is a popular technique, no method for simultaneous silencing of multiple targets by small-hairpin RNA (shRNA)-expressing RNAi vectors has yet been established. Although gene silencing can be achieved by synthetic small-interfering RNA (siRNA) duplexes, the approach is transient and largely dependent on the transfection efficiency of the host cell. We offer a solution: a simple, restriction enzyme-generated stable RNAi technique that can efficiently silence multiple targets with a single RNAi vector and a single selection marker. In this study, we succeeded in simultaneous stable knockdown of transforming growth factor beta (TGF-beta) pathway-related Smads--Smad2, Smad3 and Smad4--at the cellular level. We observed distinct phenotypic changes in TGF-beta-dependent cellular functions such as invasion, wound healing and apoptosis. This method is best suited for an analysis of complex signal transduction pathways in which silencing of a single gene cannot account for the whole process.Texto completo do artigo
|Beneficial effect of transfusion with low-affinity red blood cells in endotoxemia. |
Fei Huang, Hidetoshi Nojiri, Takahiko Shimizu, Takuji Shirasawa
Transfusion 45 1785-90 2005
BACKGROUND: Sepsis caused by endotoxins such as lipopolysaccharide (LPS) impairs the microcirculation, diminishing tissue blood supply and aggravates systemic hypoxia. A novel lower-affinity hemoglobin (Hb) variant, Hb Presbyterian, enhances oxygen release to peripheral tissues and may improve tissue oxygen supply during sepsis. STUDY DESIGN AND METHODS: This study investigated the effectiveness of Presbyterian Hb in transfusion therapy with LPS-challenged sepsis mouse model. Septic wild-type mice were transfused with RBCs from Presbyterian Hb-carrying mutant mice and wild-type mice. Their survival rates were assessed, and apoptosis of hepatocytes was evaluated. Survival rates of septic Presbyterian mutant mice and the wild-type littermates were also studied. RESULTS: The Presbyterian mutant RBC-transfused septic group survived longer than the wild-type RBC-transfused group. Apoptosis was reduced in the hepatocytes of the former group. Presbyterian mutant mice themselves, however, did not have stronger resistance to LPS-induced sepsis. CONCLUSION: Transfusion of low-affinity Hb-containing RBCs has beneficial effects in septic mice.
|Interferon-gamma induced medulloblastoma in the developing cerebellum. |
Lin, Wensheng, et al.
J. Neurosci., 24: 10074-83 (2004) 2004
We have generated a mouse model system with a high incidence of medulloblastoma, a malignant neoplasm believed to arise from immature precursors of cerebellar granule neurons. These animals ectopically express interferon-gamma (IFN-gamma) in astrocytes in the CNS in a controlled manner, exploiting the tetracycline-controllable system. More than 80% of these mice display severe ataxia and develop cerebellar tumors that express synaptophysin, the mouse atonal homolog MATH1, sonic hedgehog (SHH), and Gli1. IFN-gamma-induced tumorigenesis in these mice is associated with increased expression of SHH, and SHH induction and tumorigenesis are dependent on signal transducer and activator of transcription 1 (STAT1). When IFN-gamma expression is shut down with doxycycline at postnatal day 12 (P12), the clinical symptoms dissipate and the mice do not develop tumors, whereas if transgene expression is shut down at P16, the clinical symptoms and tumors progress to lethality, indicating that IFN-gamma is required for tumor induction but not progression. The tumors that occur in the continued presence of IFN-gamma display extensive necrosis and apoptosis as well as macrophage and lymphocytic infiltration, whereas the tumors that develop in mice in which IFN-gamma expression is shut down at P16 do not. Thus, IFN-gamma expression in the perinatal period can induce SHH expression and medulloblastoma in the cerebellum by a STAT1-dependent mechanism, and its continued presence appears to promote a host response to the tumor.
|Ectodermal Wnt3/beta-catenin signaling is required for the establishment and maintenance of the apical ectodermal ridge. |
Barrow, Jeffery R, et al.
Genes Dev., 17: 394-409 (2003) 2003
|Choline availability during embryonic development alters progenitor cell mitosis in developing mouse hippocampus. |
Corneliu N Craciunescu,Craig D Albright,Mei-Heng Mar,Jiannan Song,Steven H Zeisel
The Journal of nutrition 133 2003
Previously, we reported that dietary choline influences development of the hippocampus in fetal rat brain. It is important to know whether similar effects of choline occur in developing fetal mouse brain because interesting new experimental approaches are now available using several transgenic mouse models. Timed-pregnant mice were fed choline-supplemented (CS), control (CT) or choline-deficient (CD) AIN-76 diet from embryonic day 12 to 17 (E12-17). Fetuses from CD dams had diminished concentrations of phosphocholine and phosphatidylcholine in their brains compared with CT or CS fetuses (P < 0.05). When we analyzed fetal hippocampus on day E17 for cells with mitotic phase-specific expression of phosphorylated histone H3, we detected fewer labeled cells at the ventricular surface of the ventricular zone in the CD group (14.8 +/- 1.9) compared with the CT (30.7 +/- 1.9) or CS (36.6 +/- 2.6) group (P < 0.05). At the same time, we detected more apoptotic cells in E17 hippocampus using morphology in the CD group (11.8 +/- 1.4) than in CT (5.6 +/- 0.6) or CS (4.2 +/- 0.7) group (P < 0.05). This was confirmed using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin anti-digoxigenin fluorescein conjugate antibody nick end-labeling (TUNEL) and activated caspase-3 immunoreactivity. We conclude that the dietary availability of choline to the mouse dam influences progenitor cell proliferation and apoptosis in the fetal brain.Texto completo do artigo
|Advancing cancer research: From hallmarks & biomarkers to tumor microenvironment progression|
|Comprehensive solutions for studying cell health - Life, death, and everything in between.|
|A Comparative Analysis of Human Embryonic Stem Cells Cultured in a Variety of Media Conditions|