Tabela com principais espec.
|Species Reactivity||Key Applications||Host||Format||Antibody Type|
|R, M||WB||Rb||Purified||Polyclonal Antibody|
|Presentation||Purified rabbit polyclonal in buffer containing 0.014 M phosphate buffer, pH 7.6, 0.175 M NaCl, 0.07% sodium azide, and 30% glycerol.|
|Application||This Anti-TrkB Antibody is validated for use in WB for the detection of TrkB.|
|Safety Information according to GHS|
|Storage and Shipping Information|
|Storage Conditions||Stable for 1 year at -20ºC from date of receipt.|
|Material Size||200 µg|
|Título||Número do lote|
|Anti-PPAR - 2293832||2293832|
|Anti-TrkB - 2392298||2392298|
|Anti-TrkB - 0609040498||0609040498|
|Anti-TrkB - 2019515||2019515|
|Anti-TrkB - 20475||20475|
|Anti-TrkB - 2090150||2090150|
|Anti-TrkB - 2187222||2187222|
|Anti-TrkB - 2293830||2293830|
|Anti-TrkB - 28846||28846|
|Anti-TrkB - DAM1408774||DAM1408774|
|Anti-TrkB - DAM1588242||DAM1588242|
|Anti-TrkB - DAM1658695||DAM1658695|
|Anti-TrkB - DAM1703503||DAM1703503|
|Anti-TrkB - DAM1724046||DAM1724046|
|Anti-TrkB - DAM1764441||DAM1764441|
|Anti-TrkB - DAM1794308||DAM1794308|
|Anti-TrkB - JBC1361713||JBC1361713|
|Anti-TrkB - JBC1863999||JBC1863999|
|Anti-TrkB - JBC1940053||JBC1940053|
Referências | 23 Disponível | Ver todas as referências
|Visão geral das referências||Aplicação||Pub Med ID|
|Mature brain-derived neurotrophic factor and its receptor TrkB are upregulated in human glioma tissues. |
Xiong, J; Zhou, LI; Lim, Y; Yang, M; Zhu, YH; Li, ZW; Fu, DL; Zhou, XF
Oncology letters 10 223-227 2015
There are two forms of brain-derived neurotrophic factor (BDNF), precursor of BDNF (proBDNF) and mature BDNF, which each exert opposing effects through two different transmembrane receptor signaling systems, consisting of p75 neurotrophin receptor (p75NTR) and tyrosine receptor kinase B (TrkB). Previous studies have demonstrated that proBDNF promotes cell death and inhibits the growth and migration of C6 glioma cells through p75NTR in vitro, while mature BDNF has opposite effects on C6 glioma cells. It is hypothesized that mature BDNF is essential in the development of malignancy in gliomas. However, histological data obtained in previous studies were unable distinguish mature BDNF from proBDNF due to the lack of specific antibodies. The present study investigated the expression of mature BDNF using a specific sheep monoclonal anti-mature BDNF antibody in 42 human glioma tissues of different grades and 10 control tissues. The correlation between mature BDNF and TrkB was analyzed. Mature BDNF expression was significantly increased in high-grade gliomas, and was positively correlated with the malignancy of the tumor and TrkB receptor expression. The present data have demonstrated that increased levels of mature BDNF contribute markedly to the development of malignancy of human gliomas through the primary BDNF receptor TrkB.
|Direct visualization of newly synthesized target proteins in situ. |
tom Dieck, S; Kochen, L; Hanus, C; Heumüller, M; Bartnik, I; Nassim-Assir, B; Merk, K; Mosler, T; Garg, S; Bunse, S; Tirrell, DA; Schuman, EM
Nature methods 12 411-4 2015
Protein synthesis is a dynamic process that tunes the cellular proteome in response to internal and external demands. Metabolic labeling approaches identify the general proteomic response but cannot visualize specific newly synthesized proteins within cells. Here we describe a technique that couples noncanonical amino acid tagging or puromycylation with the proximity ligation assay to visualize specific newly synthesized proteins and monitor their origin, redistribution and turnover in situ.
|Trkb signaling in pericytes is required for cardiac microvessel stabilization. |
Anastasia, A; Deinhardt, K; Wang, S; Martin, L; Nichol, D; Irmady, K; Trinh, J; Parada, L; Rafii, S; Hempstead, BL; Kermani, P
PloS one 9 e87406 2014
Pericyte and vascular smooth muscle cell (SMC) recruitment to the developing vasculature is an important step in blood vessel maturation. Brain-derived neurotrophic factor (BDNF), expressed by endothelial cells, activates the receptor tyrosine kinase TrkB to stabilize the cardiac microvasculature in the perinatal period. However, the effects of the BDNF/TrkB signaling on pericytes/SMCs and the mechanisms downstream of TrkB that promote vessel maturation are unknown. To confirm the involvement of TrkB in vessel maturation, we evaluated TrkB deficient (trkb (-/-)) embryos and observed severe cardiac vascular abnormalities leading to lethality in late gestation to early prenatal life. Ultrastructural analysis demonstrates that trkb(-/-) embryos exhibit defects in endothelial cell integrity and perivascular edema. As TrkB is selectively expressed by pericytes and SMCs in the developing cardiac vasculature, we generated mice deficient in TrkB in these cells. Mice with TrkB deficiency in perivascular cells exhibit reduced pericyte/SMC coverage of the cardiac microvasculature, abnormal endothelial cell ultrastructure, and increased vascular permeability. To dissect biological actions and the signaling pathways downstream of TrkB in pericytes/SMCs, human umbilical SMCs were treated with BDNF. This induced membranous protrusions and cell migration, events dependent on myosin light chain phosphorylation. Moreover, inhibition of Rho GTPase and the Rho-associated protein kinase (ROCK) prevented membrane protrusion and myosin light chain phosphorylation in response to BDNF. These results suggest an important role for BDNF in regulating migration of TrkB-expressing pericytes/SMCs to promote cardiac blood vessel ensheathment and functional integrity during development.
|A monoclonal antibody TrkB receptor agonist as a potential therapeutic for Huntington's disease. |
Todd, D; Gowers, I; Dowler, SJ; Wall, MD; McAllister, G; Fischer, DF; Dijkstra, S; Fratantoni, SA; van de Bospoort, R; Veenman-Koepke, J; Flynn, G; Arjomand, J; Dominguez, C; Munoz-Sanjuan, I; Wityak, J; Bard, JA
PloS one 9 e87923 2014
Huntington's disease (HD) is a devastating, genetic neurodegenerative disease caused by a tri-nucleotide expansion in exon 1 of the huntingtin gene. HD is clinically characterized by chorea, emotional and psychiatric disturbances and cognitive deficits with later symptoms including rigidity and dementia. Pathologically, the cortico-striatal pathway is severely dysfunctional as reflected by striatal and cortical atrophy in late-stage disease. Brain-derived neurotrophic factor (BDNF) is a neuroprotective, secreted protein that binds with high affinity to the extracellular domain of the tropomyosin-receptor kinase B (TrkB) receptor promoting neuronal cell survival by activating the receptor and down-stream signaling proteins. Reduced cortical BDNF production and transport to the striatum have been implicated in HD pathogenesis; the ability to enhance TrkB signaling using a BDNF mimetic might be beneficial in disease progression, so we explored this as a therapeutic strategy for HD. Using recombinant and native assay formats, we report here the evaluation of TrkB antibodies and a panel of reported small molecule TrkB agonists, and identify the best candidate, from those tested, for in vivo proof of concept studies in transgenic HD models.
|Molecular mechanisms mediating a deficit in recall of fear extinction in adult mice exposed to cocaine in utero. |
Kabir, ZD; Katzman, AC; Kosofsky, BE
PloS one 8 e84165 2013
Prenatal cocaine exposure has been shown to alter cognitive processes of exposed individuals, presumed to be a result of long-lasting molecular alterations in the brain. In adult prenatal cocaine exposed (PCOC) mice we have identified a deficit in recall of fear extinction, a behavior that is dependent on the medial prefrontal cortex (mPFC) and the hippocampus. While we observed no change in the constitutive expression of brain derived neurotrophic factor (BDNF) protein and mRNA in the mPFC and hippocampus of adult PCOC mice, we observed blunted BDNF signaling in the mPFC of adult PCOC mice after fear extinction compared to the control animals. Specifically, during the consolidation phase of the extinction memory, we observed a decrease in BDNF protein and it's phospho-TrkB receptor expression. Interestingly, at this same time point there was a significant increase in total Bdnf mRNA levels in the mPFC of PCOC mice as compared with controls. In the Bdnf gene, we identified decreased constitutive binding of the transcription factors, MeCP2 and P-CREB at the promoters of Bdnf exons I and IV in the mPFC of PCOC mice, that unlike control mice remained unchanged when measured during the behavior. Finally, bilateral infusion of recombinant BDNF protein into the infralimbic subdivision of the mPFC during the consolidation phase of the extinction memory rescued the behavioral deficit in PCOC mice. In conclusion, these findings extend our knowledge of the neurobiologic impact of prenatal cocaine exposure on the mPFC of mice, which may lead to improved clinical recognition and treatment of exposed individuals.
|EGF transactivation of Trk receptors regulates the migration of newborn cortical neurons. |
Puehringer, D; Orel, N; Lüningschrör, P; Subramanian, N; Herrmann, T; Chao, MV; Sendtner, M
Nature neuroscience 16 407-15 2013
The development of neuronal networks in the neocortex depends on control mechanisms for mitosis and migration that allow newborn neurons to find their accurate position. Multiple mitogens, neurotrophic factors, guidance molecules and their corresponding receptors are involved in this process, but the mechanisms by which these signals are integrated are only poorly understood. We found that TrkB and TrkC, the receptors for brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), are activated by epidermal growth factor receptor (EGFR) signaling rather than by BDNF or NT-3 in embryonic mouse cortical precursor cells. This transactivation event regulated migration of early neuronal cells to their final position in the developing cortex. Transactivation by EGF led to membrane translocation of TrkB, promoting its signaling responsiveness. Our results provide genetic evidence that TrkB and TrkC activation in early cortical neurons do not depend on BDNF and NT-3, but instead on transactivation by EGFR signaling.
|Different roles of BDNF in nucleus accumbens core versus shell during the incubation of cue-induced cocaine craving and its long-term maintenance. |
Li, X; DeJoseph, MR; Urban, JH; Bahi, A; Dreyer, JL; Meredith, GE; Ford, KA; Ferrario, CR; Loweth, JA; Wolf, ME
The Journal of neuroscience : the official journal of the Society for Neuroscience 33 1130-42 2013
Brain-derived neurotrophic factor (BDNF) contributes to diverse types of plasticity, including cocaine addiction. We investigated the role of BDNF in the rat nucleus accumbens (NAc) in the incubation of cocaine craving over 3 months of withdrawal from extended access cocaine self-administration. First, we confirmed by immunoblotting that BDNF levels are elevated after this cocaine regimen on withdrawal day 45 (WD45) and showed that BDNF mRNA levels are not altered. Next, we explored the time course of elevated BDNF expression using immunohistochemistry. Elevation of BDNF in the NAc core was detected on WD45 and further increased on WD90, whereas elevation in shell was not detected until WD90. Surface expression of activated tropomyosin receptor kinase B (TrkB) was also enhanced on WD90. Next, we used viral vectors to attenuate BDNF-TrkB signaling. Virus injection into the NAc core enhanced cue-induced cocaine seeking on WD1 compared with controls, whereas no effect was observed on WD30 or WD90. Attenuating BDNF-TrkB signaling in shell did not affect cocaine seeking on WD1 or WD45 but significantly decreased cocaine seeking on WD90. These results suggest that basal levels of BDNF transmission in the NAc core exert a suppressive effect on cocaine seeking in early withdrawal (WD1), whereas the late elevation of BDNF protein in NAc shell contributes to incubation in late withdrawal (WD90). Finally, BDNF protein levels in the NAc were significantly increased after ampakine treatment, supporting the novel hypothesis that the gradual increase of BDNF levels in NAc accompanying incubation could be caused by increased AMPAR transmission during withdrawal.
|Passive exercise of the hind limbs after complete thoracic transection of the spinal cord promotes cortical reorganization. |
Graziano, A; Foffani, G; Knudsen, EB; Shumsky, J; Moxon, KA
PloS one 8 e54350 2013
Physical exercise promotes neural plasticity in the brain of healthy subjects and modulates pathophysiological neural plasticity after sensorimotor loss, but the mechanisms of this action are not fully understood. After spinal cord injury, cortical reorganization can be maximized by exercising the non-affected body or the residual functions of the affected body. However, exercise per se also produces systemic changes - such as increased cardiovascular fitness, improved circulation and neuroendocrine changes - that have a great impact on brain function and plasticity. It is therefore possible that passive exercise therapies typically applied below the level of the lesion in patients with spinal cord injury could put the brain in a more plastic state and promote cortical reorganization. To directly test this hypothesis, we applied passive hindlimb bike exercise after complete thoracic transection of the spinal cord in adult rats. Using western blot analysis, we found that the level of proteins associated with plasticity - specifically ADCY1 and BDNF - increased in the somatosensory cortex of transected animals that received passive bike exercise compared to transected animals that received sham exercise. Using electrophysiological techniques, we then verified that neurons in the deafferented hindlimb cortex increased their responsiveness to tactile stimuli delivered to the forelimb in transected animals that received passive bike exercise compared to transected animals that received sham exercise. Passive exercise below the level of the lesion, therefore, promotes cortical reorganization after spinal cord injury, uncovering a brain-body interaction that does not rely on intact sensorimotor pathways connecting the exercised body parts and the brain.
|Quantitative analysis of BDNF/TrkB protein and mRNA in cortical and striatal neurons using α-tubulin as a normalization factor. |
Ma, B; Savas, JN; Chao, MV; Tanese, N
Cytometry. Part A : the journal of the International Society for Analytical Cytology 81 704-17 2012
The neurotrophin brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase TrkB serve important regulatory roles for multiple aspects of the biology of neurons including cell death, survival, growth, differentiation, and plasticity. Regulation of the local availability of BDNF/TrkB at distinct subcellular domains such as soma, dendrites, axons, growth cones, nerve terminals, and spines appears to contribute to their specific functions. In view of the variance in size and shape of neurons and their compartments, previous quantitative studies of the BDNF/TrkB protein and mRNA lacked a robust normalization procedure. To overcome this problem, we have established methods that use immunofluorescence detection of α-tubulin as a normalization factor for the quantitative analysis of protein and mRNA in primary rat cortical and striatal neurons in culture. The efficacy of this approach is demonstrated by studying the dynamic distribution of proteins and mRNA at different growth stages or conditions. Treatment of cultured neurons with KCl resulted in increased levels of TrkB protein, reduced levels of BDNF mRNA (composite of multiple transcripts) and a slight reduction in BDNF protein levels in the dendrites from the cortex. The KCl treatment also lowered the percentage of BDNF and TrkB proteins in the soma indicative of protein transport. Finally, analysis of the rat cortical and striatal neurons demonstrated comparable or even higher levels of BDNF/TrkB protein and BDNF mRNA in the neurons from the striatum. Thus, in contrast to previous observations made in vivo, striatal neurons are capable of synthesizing BDNF mRNA when cultured in growth media in vitro. The analytical approach presented here provides a detailed understanding of BDNF/TrkB levels in response to a variety of neuronal activities. Our methods could be used broadly, including applications in cell and tissue cytometry, to yield accurate quantitative data of gene expression in cellular and subcellular contexts. © 2012 International Society for Advancement of Cytometry.
|Kidins220/ARMS mediates the integration of the neurotrophin and VEGF pathways in the vascular and nervous systems. |
Cesca, F; Yabe, A; Spencer-Dene, B; Scholz-Starke, J; Medrihan, L; Maden, CH; Gerhardt, H; Orriss, IR; Baldelli, P; Al-Qatari, M; Koltzenburg, M; Adams, RH; Benfenati, F; Schiavo, G
Cell death and differentiation 19 194-208 2012
Signaling downstream of receptor tyrosine kinases controls cell differentiation and survival. How signals from different receptors are integrated is, however, still poorly understood. In this work, we have identified Kidins220 (Kinase D interacting substrate of 220 kDa)/ARMS (Ankyrin repeat-rich membrane spanning) as a main player in the modulation of neurotrophin and vascular endothelial growth factor (VEGF) signaling in vivo, and a primary determinant for neuronal and cardiovascular development. Kidins220(-/-) embryos die at late stages of gestation, and show extensive cell death in the central and peripheral nervous systems. Primary neurons from Kidins220(-/-) mice exhibit reduced responsiveness to brain-derived neurotrophic factor, in terms of activation of mitogen-activated protein kinase signaling, neurite outgrowth and potentiation of excitatory postsynaptic currents. In addition, mice lacking Kidins220 display striking cardiovascular abnormalities, possibly due to impaired VEGF signaling. In support of this hypothesis, we demonstrate that Kidins220 constitutively interacts with VEGFR2. These findings, together with the data presented in the accompanying paper, indicate that Kidins220 mediates the integration of several growth factor receptor pathways during development, and mediates the activation of distinct downstream cascades according to the location and timing of stimulation.
|Brain-derived neurotrophic factor promotes adaptive plasticity within the spinal cord and mediates the beneficial effects of controllable stimulation. |
Huie, JR; Garraway, SM; Baumbauer, KM; Hoy, KC; Beas, BS; Montgomery, KS; Bizon, JL; Grau, JW
Neuroscience 200 74-90 2012
Brain-derived neurotrophic factor (BDNF) has been characterized as a potent modulator of neural plasticity in both the brain and spinal cord. The present experiments use an in vivo model system to demonstrate that training with controllable stimulation increases spinal BDNF expression and engages a BDNF-dependent process that promotes adaptive plasticity. Spinally transected rats administered legshock whenever one hind limb is extended (controllable stimulation) exhibit a progressive increase in flexion duration. This simple form of response-outcome (instrumental) learning is not observed when shock is given independent of leg position (uncontrollable stimulation). Uncontrollable electrical stimulation also induces a lasting effect that impairs learning for up to 48 h. Training with controllable shock can counter the adverse consequences of uncontrollable stimulation, to both prevent and reverse the learning deficit. Here it is shown that the protective and restorative effect of instrumental training depends on BDNF. Cellular assays showed that controllable stimulation increased BDNF mRNA expression and protein within the lumbar spinal cord. These changes were associated with an increase in the BDNF receptor TrkB protein within the dorsal horn. Evidence is then presented that these changes play a functional role in vivo. Application of a BDNF inhibitor (TrkB-IgG) blocked the protective effect of instrumental training. Direct (intrathecal) application of BDNF substituted for instrumental training to block both the induction and expression of the learning deficit. Uncontrollable stimulation also induced an increase in mechanical reactivity (allodynia), and this too was prevented by BDNF. TrkB-IgG blocked the restorative effect of instrumental training and intrathecal BDNF substituted for training to reverse the deficit. Taken together, these findings outline a critical role for BDNF in mediating the beneficial effects of controllable stimulation on spinal plasticity.
|Impairment of select forms of spatial memory and neurotrophin-dependent synaptic plasticity by deletion of glial aquaporin-4. |
Skucas, VA; Mathews, IB; Yang, J; Cheng, Q; Treister, A; Duffy, AM; Verkman, AS; Hempstead, BL; Wood, MA; Binder, DK; Scharfman, HE
The Journal of neuroscience : the official journal of the Society for Neuroscience 31 6392-7 2011
Aquaporin-4 (AQP4) is the major water channel in the CNS and is primarily expressed in astrocytes. Little is known about the potential for AQP4 to influence synaptic plasticity, although many studies have shown that it regulates the response of the CNS to injury. Therefore, we evaluated long-term potentiation (LTP) and long-term depression (LTD) in AQP4 knock-out (KO) and wild-type mice. KO mice exhibited a selective defect in LTP and LTD without a change in basal transmission or short-term plasticity. Interestingly, the impairment in LTP in KO mice was specific for the type of LTP that depends on the neurotrophin BDNF, which is induced by stimulation at theta rhythm [theta-burst stimulation (TBS)-LTP], but there was no impairment in a form of LTP that is BDNF independent, induced by high-frequency stimulation. LTD was also impaired in KO mice, which was rescued by a scavenger of BDNF or blockade of Trk receptors. TrkB receptors, which mediate effects of BDNF on TBS-LTP, were not altered in KO mice, but p75NTR, the receptor that binds all neurotrophins and has been implicated in some types of LTD, was decreased. The KO mice also exhibited a cognitive defect, which suggests a new role for AQP4 and astrocytes in normal cognitive function. This defect was evident using a test for location-specific object memory but not Morris water maze or contextual fear conditioning. The results suggest that AQP4 channels in astrocytes play an unanticipated role in neurotrophin-dependent plasticity and influence behavior.
|Ethanol alters bDNF-Induced rho gTPase activation in axonal growth cones. |
Lindsley TA, Shah SN, Ruggiero EA
Alcoholism, clinical and experimental research 35 1321-30. doi 2011
Background: The effects of ethanol on development of postmitotic neurons include altered neurite outgrowth and differentiation, which may contribute to neuropathology associated with fetal alcohol spectrum disorders. We previously reported that ethanol exposure alters axon growth dynamics in dissociated cultures of rat hippocampal pyramidal neurons. Given the important regulatory role of small Rho guanosine triphosphatases (GTPases) in cytoskeletal reorganization associated with axon growth, and reports that ethanol alters whole cell Rho GTPase activity in other cell types, this study explored the hypothesis that ethanol alters Rho GTPase activity specifically in axonal growth cones. Methods: Fetal rat hippocampal pyramidal neurons were maintained in dissociated cultures for 1 day in control medium or medium containing 11 to 43 mM ethanol. Some cultures were also treated with brain-derived neurotrophic factor (BDNF), an activator of Rac1 and Cdc42 GTPases that promotes axon extension. Levels of active Rho GTPases in growth cones were measured using in situ binding assays for GTP-bound Rac1, Cdc42, and RhoA. Axon length, growth cone area, and growth cone surface expression of tyrosine kinase B (TrkB), the receptor for BDNF, were assessed by digital morphometry and immunocytochemistry. Results: Although ethanol increased the surface area of growth cones, the levels of active Rho GTPases in axonal growth cones were not affected in the absence of exogenous BDNF. In contrast, ethanol exposure inhibited BDNF-induced Rac1/Cdc42 activation in a dose-dependent manner and increased RhoA activation at the highest concentration tested. Similar TrkB expression was observed on the surface of axonal growth cones of control and ethanol-treated neurons. Conclusions: These results reveal an inhibitory effect of ethanol on growth cone signaling via small Rho GTPases during early stages of hippocampal development in vitro, and suggest a mechanism whereby ethanol may disrupt neurotrophic factor regulation of axon growth and guidance.Copyright © 2011 by the Research Society on Alcoholism.
|Pharmacological characterization of six trkB antibodies reveals a novel class of functional agents for the study of the BDNF receptor. |
M Cazorla,J M Arrang,J Prémont
British journal of pharmacology 162 2011
By interacting with trkB receptors, brain-derived neurotrophic factor (BDNF) triggers various signalling pathways responsible for neurone survival, differentiation and modulation of synaptic transmission. Numerous reports have implicated BDNF and trkB in the pathogenesis of various central nervous system affections and in cancer, thus representing trkB as a promising therapeutic target. In this study, we used an antibody-based approach to search for trkB-selective functional reagents.
|JIP3 mediates TrkB axonal anterograde transport and enhances BDNF signaling by directly bridging TrkB with kinesin-1. |
Huang, SH; Duan, S; Sun, T; Wang, J; Zhao, L; Geng, Z; Yan, J; Sun, HJ; Chen, ZY
The Journal of neuroscience : the official journal of the Society for Neuroscience 31 10602-14 2011
Brain-derived neurotrophic factor (BDNF), secreted from target tissues, binds and activates TrkB receptors, located on axonal terminals of the innervating neurons, and thereby initiates retrograde signaling. Long-range anterograde transport of TrkB in axons and dendrites requires kinesin-mediated transport. However, it remains unknown whether anterograde TrkB transport mechanisms are the same in axons versus in dendrites. Here, we show that c-Jun NH(2)-terminal kinase-interacting protein 3 (JIP3) binds directly to TrkB, via a minimal 12 aa domain in the TrkB juxtamembrane region, and links TrkB to kinesin-1. The JIP3/TrkB interaction selectively drives TrkB anterograde transport in axons but not in dendrites of rat hippocampal neurons. Moreover, we find that TrkB axonal transport mediated by JIP3 could regulate BDNF-induced Erk activation and axonal filopodia formation. Our findings demonstrate a role for JIP3-mediated TrkB anterograde axonal transport in recruiting more TrkB into distal axons and facilitating BDNF-induced retrograde signaling and synapse modulation, which provides a novel mechanism of how the TrkB anterograde transport can be coupled to BDNF signaling in distal axons.
|Intermittent noxious stimulation following spinal cord contusion injury impairs locomotor recovery and reduces spinal brain-derived neurotrophic factor-tropomyosin-receptor kinase signaling in adult rats. |
Garraway, SM; Turtle, JD; Huie, JR; Lee, KH; Hook, MA; Woller, SA; Grau, JW
Neuroscience 199 86-102 2011
Intermittent nociceptive stimulation following a complete transection or contused spinal cord injury (SCI) has been shown to exert several short- and long-lasting negative consequences. These include maladaptive spinal plasticity, enhanced mechanical allodynia, and impaired functional recovery of locomotor and bladder functions. The neurotrophin, brain-derived neurotrophic factor (BDNF) has been shown to play an important role in adaptive plasticity and also to restore functions following SCI. This suggests that the negative behavioral effects of shock are most likely related to corresponding changes in BDNF spinal levels. In this study, we investigated the cellular effects of nociceptive stimulation in contused adult rats focusing on BDNF, its receptor, tropomyosin-receptor kinase (TrkB), and the subsequent downstream signaling system. The goal was to determine whether the behavioral effect of stimulation is associated with concomitant cellular changes induced during the initial post-injury period. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used to assess changes in the mRNA and/or protein levels of BDNF, TrkB, and the downstream signaling proteins calcium-calmodulin kinase II (CaMKII) and extracellular related kinase 1/2 (ERK1/2) at 1 h, 24 h, and 7 days following administration of intermittent noxious shock to the tail of contused subjects. In addition, recovery of locomotor function (Basso, Beattie, and Bresnahan [BBB] score) was assessed daily for the first week after injury. The results showed that, although nociceptive stimulation failed to induce any changes in gene expression at 1 h, it significantly reduced the expression of BDNF, TrkB, ERK2, and CaMKII at 24 h. In general, changes in gene expression were spatially localized to the dorsal spinal cord. In addition, locomotor recovery was impaired by shock. Evidence is also provided suggesting that shock engages a neuronal circuitry without having any negative effects on neuronal survival at 24 h. These results suggest that nociceptive activity following SCI decreases BDNF and TrkB levels, which may significantly contribute to diminished functional recovery.
|Brain-derived neurotrophic factor rapidly increases AMPA receptor surface expression in rat nucleus accumbens. |
Li, X; Wolf, ME
The European journal of neuroscience 34 190-8 2011
In the rodent nucleus accumbens (NAc), cocaine elevates levels of brain-derived neurotrophic factor (BDNF). Conversely, BDNF can augment cocaine-related behavioral responses. The latter could reflect enhancement of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) transmission, because AMPARs in the NAc mediate some cocaine-induced behaviors. Furthermore, in vitro studies in other cell types show that BDNF can promote AMPAR synaptic delivery. In this study, we investigated whether BDNF similarly promotes AMPAR trafficking in the adult rat NAc. After unilateral intracranial injection of BDNF into NAc core or shell, rats were killed at post-injection times ranging from 30 min to 3 days. NAc core or shell tissue from both injected and non-injected hemispheres was analysed by Western blotting. A protein cross-linking assay was used to measure AMPAR surface expression. Assessment of tropomyosin receptor kinase B signaling demonstrated that injected BDNF was biologically active. BDNF injection into NAc core, but not NAc shell, led to a protein synthesis- and extracellular signal-regulated kinase-dependent increase in cell surface GluA1 and a trend towards increased total GluA1. This was detected 30 min post-injection but not at longer time-points. GluA2 and GluA3 were unaffected, suggesting an effect of BDNF on homomeric GluA1 Ca(2+) -permeable AMPARs. These results demonstrate that exogenous BDNF rapidly increases AMPAR surface expression in the rat NAc core, raising the possibility of a relationship between increases in endogenous BDNF levels and alterations in AMPAR transmission observed in the NAc of cocaine-experienced rats.
|Neurotrophin receptor TrkC is an entry receptor for Trypanosoma cruzi in neural, glial, and epithelial cells. |
Weinkauf, C; Salvador, R; Pereiraperrin, M
Infection and immunity 79 4081-7 2011
Trypanosoma cruzi, the agent of Chagas' disease, infects a variety of mammalian cells in a process that includes multiple cycles of intracellular division and differentiation starting with host receptor recognition by a parasite ligand(s). Earlier work in our laboratory showed that the neurotrophin-3 (NT-3) receptor TrkC is activated by T. cruzi surface trans-sialidase, also known as parasite-derived neurotrophic factor (PDNF). However, it has remained unclear whether TrkC is used by T. cruzi to enter host cells. Here, we show that a neuronal cell line (PC12-NNR5) relatively resistant to T. cruzi became highly susceptible to infection when overexpressing human TrkC but not human TrkB. Furthermore, trkC transfection conferred an ∼3.0-fold intracellular growth advantage. Sialylation-deficient Chinese hamster ovarian (CHO) epithelial cell lines Lec1 and Lec2 also became much more permissive to T. cruzi after transfection with the trkC gene. Additionally, NT-3 specifically blocked T. cruzi infection of the TrkC-NNR5 transfectants and of naturally permissive TrkC-bearing Schwann cells and astrocytes, as did recombinant PDNF. Two specific inhibitors of Trk autophosphorylation (K252a and AG879) and inhibitors of Trk-induced MAPK/Erk (U0126) and Akt kinase (LY294002) signaling, but not an inhibitor of insulin-like growth factor 1 receptor, abrogated TrkC-mediated cell invasion. Antibody to TrkC blocked T. cruzi infection of the TrkC-NNR5 transfectants and of cells that naturally express TrkC. The TrkC antibody also significantly and specifically reduced cutaneous infection in a mouse model of acute Chagas' disease. TrkC is ubiquitously expressed in the peripheral and central nervous systems, and in nonneural cells infected by T. cruzi, including cardiac and gastrointestinal muscle cells. Thus, TrkC is implicated as a functional PDNF receptor in cell entry, independently of sialic acid recognition, mediating broad T. cruzi infection both in vitro and in vivo.
|MafA transcription factor identifies the early ret-expressing sensory neurons. |
Laure Lecoin,Nathalie Rocques,Warif El-Yakoubi,Sarrah Ben Achour,Magalie Larcher,Celio Pouponnot,Alain Eychène
Developmental neurobiology 70 2010
Dorsal root ganglia proceed from the coalescence of cell bodies of sensory neurons, which have migrated dorsoventrally from the delaminating neural crest. They are composed of different neuronal subtypes with specific sensory functions, including nociception, thermal sensation, proprioception, and mechanosensation. In contrast to proprioceptors and thermonociceptors, little is known about the molecular mechanisms governing the early commitment and later differentiation into mechanosensitive neurons. This is mainly due to the absence of specific molecular markers for this particular cell type. Using knockout mice, we identified the bZIP transcription factor MafA as the first specific marker of a subpopulation of early c-ret positive neurons characterized by medium-to-large diameters. This marker will allow further functional characterization of these neurons.
|Brain-derived neurotrophic factor signaling does not stimulate subventricular zone neurogenesis in adult mice and rats. |
Galvão, RP; Garcia-Verdugo, JM; Alvarez-Buylla, A
The Journal of neuroscience : the official journal of the Society for Neuroscience 28 13368-83 2008
In rodents, the adult subventricular zone (SVZ) generates neuroblasts which migrate to the olfactory bulb (OB) and differentiate into interneurons. Recent work suggests that the neurotrophin Brain-Derived Neurotrophic Factor (BDNF) can enhance adult SVZ neurogenesis, but the mechanism by which it acts is unknown. Here, we analyzed the role of BDNF and its receptor TrkB in adult SVZ neurogenesis. We found that TrkB is the most prominent neurotrophin receptor in the mouse SVZ, but only the truncated, kinase-negative isoform (TrkB-TR) was detected. TrkB-TR is expressed in SVZ astrocytes and ependymal cells, but not in neuroblasts. TrkB mutants have reduced SVZ proliferation and survival and fewer new OB neurons. To test whether this effect is cell-autonomous, we grafted SVZ cells from TrkB knock-out mice (TrkB-KO) into the SVZ of wild-type mice (WT). Grafted progenitors generated neuroblasts that migrated to the OB in the absence of TrkB. The survival and differentiation of granular interneurons and Calbindin(+) periglomerular interneurons seemed unaffected by the loss of TrkB, whereas dopaminergic periglomerular neurons were reduced. Intra-ventricular infusion of BDNF yielded different results depending on the animal species, having no effect on neuron production from mouse SVZ, while decreasing it in rats. Interestingly, mice and rats also differ in their expression of the neurotrophin receptor p75. Our results indicate that TrkB is not essential for adult SVZ neurogenesis and do not support the current view that delivering BDNF to the SVZ can enhance adult neurogenesis.
|Conventional kinesin-I motors participate in the anterograde axonal transport of neurotrophins in the visual system. |
Rafal Butowt, Christopher S von Bartheld
Journal of neuroscience research 85 2546-56 2007
Retinal ganglion cells (RGCs) anterogradely transport neurotrophins to the midbrain tectum/superior colliculus with significant downstream effects. The molecular mechanism of this type of axonal transport of neurotrophins is not well characterized. We identified kinesin-I proteins as a motor participating in the anterograde axonal movement of vesicular structures containing radiolabeled neurotrophins along the optic nerve. RT-PCR analysis of purified murine RGCs showed that adult RGCs express all known members of the kinesin-I family. After intraocular injection of (125)I-brain-derived neurotrophic factor (BDNF) into the adult mouse or (125)I-neurotrophin-3 (NT-3) into the embryonic chicken eye, radioactivity was efficiently immunoprecipitated from the optic nerve lysates by anti-kinesin heavy chain and anti-kinesin light chain monoclonal antibodies (H2 and L1). Immunoreactivity for the BDNF receptor trkB is also present in the immunoprecipitates obtained by the anti-kinesin-I antibodies. The delivery of the H2 antibody in vivo into the mouse RGCs substantially reduced anterograde axonal transport of (125)I-BDNF. Anterograde transport of BDNF was not diminished in kinesin light chain 1 (KLC1) knockout mice. However, this may be due to redundancy in functions between two different isoforms of KLC present in the RGCs, as it was described previously for kinesin heavy chains (Kanai et al. [ 2000] J Neurosci 20:6374-6384). These data indicate that kinesin-I is a protein motor that participates in the anterograde axonal transport of neurotrophins in the chicken and mouse visual pathways.
|Expression of Trk receptors in the developing mouse trigeminal ganglion: in vivo evidence for NT-3 activation of TrkA and TrkB in addition to TrkC |
Huang, E J, et al
Development, 126:2191-203 (1999) 1999
|Evidence that biological activity of NGF is mediated through a novel subclass of high affinity receptors |
Weskamp, G and Reichardt, L F
Neuron, 6:649-63 (1991) 1991