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  • A sensory-labeled line for cold: TRPM8-expressing sensory neurons define the cellular basis for cold, cold pain, and cooling-mediated analgesia. 23407943

    Many primary sensory neurons are polymodal, responding to multiple stimulus modalities (chemical, thermal, or mechanical), yet each modality is recognized differently. Although polymodality implies that stimulus encoding occurs in higher centers, such as the spinal cord or brain, recent sensory neuron ablation studies find that behavioral responses to different modalities require distinct subpopulations, suggesting the existence of modality-specific labeled lines at the level of the sensory afferent. Here we provide evidence that neurons expressing TRPM8, a cold- and menthol-gated channel required for normal cold responses in mammals, represents a labeled line solely for cold sensation. We examined the behavioral significance of conditionally ablating TRPM8-expressing neurons in adult mice, finding that, like animals lacking TRPM8 channels (Trpm8(-/-)), animals depleted of TRPM8 neurons ("ablated") are insensitive to cool to painfully cold temperatures. Ablated animals showed little aversion to noxious cold and did not distinguish between cold and a preferred warm temperature, a phenotype more profound than that of Trpm8(-/-) mice which exhibit only partial cold-avoidance and -preference behaviors. In addition to acute responses, cold pain associated with inflammation and nerve injury was significantly attenuated in ablated and Trpm8(-/-) mice. Moreover, cooling-induced analgesia after nerve injury was abolished in both genotypes. Last, heat, mechanical, and proprioceptive behaviors were normal in ablated mice, demonstrating that TRPM8 neurons are dispensable for other somatosensory modalities. Together, these data show that, although some limited cold sensitivity remains in Trpm8(-/-) mice, TRPM8 neurons are required for the breadth of behavioral responses evoked by cold temperatures.
    Document Type:
    Reference
    Product Catalog Number:
    AB1761

  • NC1 domain of collagen α3(IV) derived from the basement membrane regulates Sertoli cell blood-testis barrier dynamics. 23885308

    The blood-testis barrier (BTB) is an important ultrastructure for spermatogenesis. Delay in BTB formation in neonatal rats or its irreversible damage in adult rats leads to meiotic arrest and failure of spermatogonial differentiation beyond type A. While hormones, such as testosterone and FSH, are crucial to BTB function, little is known if there is a local regulatory mechanism in the seminiferous epithelium that modulates BTB function. Herein, we report that collagen α3(IV) chain, a component of the basement membrane in the rat testis, could generate a noncollagenous (NC1) domain peptide [Colα3(IV) NC1] via limited proteolysis by matrix metalloproteinase-9 (MMP-9), and that the expression of MMP-9 was upregulated by TNFα. While recombinant Colα3(IV) NC1 protein produced in E. coli failed to perturb Sertoli cell tight junction (TJ)-permeability barrier function, possibly due to the lack of glycosylation, Colα3(IV) NC1 recombinant protein produced in mammalian cells and purified to apparent homogeneity by affinity chromatography was found to reversibly perturb the Sertoli cell TJ-barrier function. Interestingly, Colα3(IV) NC1 recombinant protein did not perturb the steady-state levels of several TJ- (e.g., occludin, CAR, JAM-A, ZO-1) and basal ectoplasmic specialization- (e.g., N-cadherin, α-catenin, β-catenin) proteins at the BTB but induced changes in protein localization and/or distribution at the Sertoli cell-cell interface in which these proteins moved from the cell surface into the cell cytosol, thereby destabilizing the TJ function. These findings illustrate the presence of a local regulatory axis known as the BTB-basement membrane axis that regulates BTB restructuring during spermatogenesis.
    Document Type:
    Reference
    Product Catalog Number:
    MAB2081
    Product Catalog Name:
    Anti-β-Catenin Antibody, clone 5H10

  • A homozygous COL6A2 intron mutation causes in-frame triple-helical deletion and nonsense-mediated mRNA decay in a patient with Ullrich congenital muscular dystrophy. 16075202

    Ullrich congenital muscular dystrophy (UCMD) is a severe disorder caused, in most cases, by a deficiency in collagen VI microfibrils. Recessive mutations in two of the three collagen VI genes, COL6A2 and COL6A3, have been identified in eight of the nine UCMD patients reported thus far. A heterozygous COL6A1 gene deletion, resulting in a mutant protein that exerts a dominant negative effect, has recently been described in a severely affected UCMD patient. Here we describe a patient in whom reverse transcription-PCR analysis of fibroblast RNA suggested a heterozygous in-frame deletion of exon 13 in the triple-helical domain of COL6A2, which is predicted to be dominantly acting. However, a homozygous A --> G mutation at -10 of intron 12 was found in the genomic DNA. The intron mutation activated numerous cryptic splice acceptor sites, generating normal and exon 13-deleted COL6A2 mRNA, and multiple aberrant transcripts containing frameshifts that were degraded through a nonsense-mediated decay mechanism. Northern analysis indicated diminished COL6A2 mRNA expression as the primary pathogenic mechanism in this UCMD patient. Our results underscore the importance of multifaceted analyses in the accurate molecular diagnosis and interpretation of genotype-phenotype correlations of UCMD.
    Document Type:
    Reference
    Product Catalog Number:
    3303

  • Attenuation of lysyl oxidase and collagen gene expression in keratoconus patient corneal epithelium corresponds to disease severity. 25593510

    Keratoconus (KC) is characterized by progressive vision loss due to corneal thinning and structural abnormalities. It is hypothesized that KC is caused by deregulated collagen levels and collagen fibril-maturating enzyme lysyl oxidase (LOX). Further, it is currently not understood whether the gene expression deregulated by the corneal epithelium influences KC pathogenesis. We studied (i) the expressions of the LOX, collagen I (COL IA1), collagen IV (COL IVA1), MMP9, and IL6 genes in KC corneal epithelia, (ii) validated their expression levels in patient tissues, and (iii) correlated expression levels with KC disease severity. The primary goal of this study was to evaluate the importance of these genes in the progression of KC.We analyzed the gene expression levels of the key proteins LOX, collagens (COL IA1 and COL IVA1), MMP9, and IL6 in debrided corneal epithelia from a large cohort of KC patients (90 eyes) and compared them to control patients (52 eyes) without KC. We measured the total LOX activity in the tears of KC patients compared to controls. We also correlated the protein expression levels of LOX and collagens by immunohistochemistry (IHC) in primary tissues from KC patients (27 eyes) undergoing keratoplasty compared to healthy donor corneas (15 eyes).We observed a significant reduction in LOX transcript levels in KC corneal epithelia, and LOX activity in KC tears correlated with disease severity. Collagen transcripts were also reduced in KC while MMP9 transcript levels were upregulated and correlated with disease severity. IL6 was moderately increased in KC patients. IHC demonstrated a reduction in the protein expression levels of LOX in the epithelium and collagen IV in the basement membrane of KC patients compared to healthy donor corneas.The data demonstrates that the structural deformity of the KC cornea may be dependent on reduced expressions of collagens and LOX, as well as on MMP9 elevated by the corneal epithelium.
    Document Type:
    Reference
    Product Catalog Number:
    ABT112
    Product Catalog Name:
    Anti-Lysyl Oxidase (LOX) Antibody

  • Different assembly of type IV collagen on hydrophilic and hydrophobic substrata alters endothelial cells interaction. 20533192

    Considering the structural role of type IV collagen (Col IV) in the assembly of the basement membrane (BM) and the perspective of mimicking its organization for vascular tissue engineering purposes, we studied the adsorption pattern of this protein on model hydrophilic (clean glass) and hydrophobic trichloro(octadecyl)silane (ODS) surfaces known to strongly affect the behavior of other matrix proteins. The amount of fluorescently labeled Col IV was quantified showing saturation of the surface for concentration of the adsorbing solution of about 50microg/ml, but with approximately twice more adsorbed protein on ODS. AFM studies revealed a fine - nearly single molecular size - network arrangement of Col IV on hydrophilic glass, which turns into a prominent and growing polygonal network consisting of molecular aggregates on hydrophobic ODS. The protein layer forms within minutes in a concentration-dependent manner. We further found that human umbilical vein endothelial cells (HUVEC) attach less efficiently to the aggregated Col IV (on ODS), as judged by the significantly altered cell spreading, focal adhesions formation and the development of actin cytoskeleton. Conversely, the immunofluorescence studies for integrins revealed that the fine Col IV network formed on hydrophilic substrata is better recognized by the cells via both alpha1 and alpha2 heterodimers which support cellular interaction, apart from these on hydrophobic ODS where almost no clustering of integrins was observed.
    Document Type:
    Reference
    Product Catalog Number:
    MAB1973
    Product Catalog Name:
    Anti-Integrin α1 Antibody, clone FB12

  • A role for antibodies to human leukocyte antigens, collagen-V, and K-α1-Tubulin in antibody-mediated rejection and cardiac allograft vasculopathy. 21383658

    We determined the role of donor-specific antibodies (DSA) and antibodies (Abs) to self-antigens, collagen-V (Col-V), and K-α1-Tubulin (KAT) in pathogenesis of acute antibody-mediated rejection (AMR) and cardiac allograft vasculopathy (CAV) after human heart transplantation (HTx).
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple

  • Regulation of human beta-cell adhesion, motility, and insulin secretion by collagen IV and its receptor alpha1beta1. 15485856

    Collagens have been shown to influence the survival and function of cultured beta-cells; however, the utilization and function of individual collagen receptors in beta-cells is largely unknown. The integrin superfamily contains up to five collagen receptors, but we have determined that alpha(1)beta(1) is the primary receptor utilized by both fetal and adult beta-cells. Cultured beta-cells adhered to and migrated on collagen type IV (Col-IV), and these responses were mediated almost exclusively by alpha(1)beta(1). The migration of cultured beta-cells to Col-IV significantly exceeded that to other matrix components suggesting that this substrate is of unique importance for beta-cell motility. The interaction of alpha(1)beta(1) with Col-IV also resulted in significant insulin secretion at basal glucose concentrations. A subset of beta-cells in developing islets was confirmed to express alpha(1)beta(1), and this expression co-localized with Col-IV in the basal membranes of juxtaposed endothelial cells. Our findings indicate that alpha(1)beta(1) and Col-IV contribute to beta-cell functions known to be important for islet morphogenesis and glucose homeostasis.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple

  • Phagocytosis and remodeling of collagen matrices. 17276428

    The biodegradation of collagen and the deposition of new collagen-based extracellular matrices are of central importance in tissue remodeling and function. Similarly, for collagen-based biomaterials used in tissue engineering, the degradation of collagen scaffolds with accompanying cellular infiltration and generation of new extracellular matrix is critical for the integration of in vitro grown tissues in vivo. In earlier studies we observed significant impact of collagen structure on primary lung fibroblast behavior in vitro in terms of collagen uptake and matrix remodeling. Therefore, in the present work, the response of human fibroblasts (IMR-90) to the structural state of collagen was studied with respect to phagocytosis in the presence and absence of inhibitors. Protein content and transcript levels for collagen I (Col-1), matrix metalloproteinase 1 (MMP-1), matrix metalloproteinase 2 (MMP-2), tissue inhibitor of matrix metalloproteinase 1 (TIMP-1), tissue inhibitor of matrix metalloproteinase 2 (TIMP-2), and heat shock protein 70 (HSP-70) were characterized as a function of collagen matrix concentration, structure and cell culture time to assess effects on cellular collagen matrix remodeling processes. Phagocytosis of collagen was assessed quantitatively by the uptake of collagen-coated fluorescent beads incorporated into the collagen matrices. Significantly higher levels of collagen phagocytosis were observed for the cells grown on the denatured collagen versus native collagen matrices. Significant reduction in collagen phagocytosis was observed by blocking several phagocytosis pathways when the cells were grown on denatured collagen versus non-denatured collagen. Collagen phagocytosis inhibition effects were significantly greater for PDL57 IMR-90 cells versus PDL48 cells, reflecting a reduced number of collagen processing pathways available to the older cells. Transcript levels related to the deposition of new extracellular matrix proteins varied as a function of the structure of the collagen matrix presented to the cells. A four-fold increase in transcript level of Col-1 and a higher level of collagen matrix incorporation were observed for cells grown on denatured collagen versus cells grown on non-denatured collagen. The data suggest that biomaterial matrices incorporating denatured collagen may promote more active remodeling toward new extracellular matrices in comparison to cells grown on non-denatured collagen. A similar effect of cellular action toward denatured (wound-related) collagen in the remodeling of tissues in vivo may have significant impact on tissue regeneration as well as the progression of collagen-related diseases.
    Document Type:
    Reference
    Product Catalog Number:
    MAB1998Z
    Product Catalog Name:
    Anti-Integrin α2β1 Antibody, clone BHA2.1, azide free

  • Chondrogenic differentiation of human mesenchymal stem cells in collagen type I hydrogels. 17503531

    The chondrogenic differentiation of bone marrow-derived human mesenchymal stem cells (MSCs) in a collagen type I hydrogel, which is in clinical use for matrix-based autologous chondrocyte transplantation (ACT), was investigated. Collagen hydrogels with 2.5 x 10(5) MSCs/mL were fabricated and cultured for 3 weeks in a serum-free, defined, chondrogenic differentiation medium containing 10 ng/mL TGF-beta1 or 100 ng/mL BMP-2. Histochemistry revealed morphologically distinct, chondrocyte-like cells, surrounded by a sulfated proteoglycan-rich extracellular matrix in the TGF-beta1 and BMP-2 treated group, with more elongated cells seen in the BMP-2 treated group. Immunohistochemistry detected collagen type II (Col II) in the TGF-beta1 and BMP-2 treated group. Collagen type X (Col X) staining was positive in the TGF-beta1 but only very weak in the BMP-2 treated group. RT-PCR analyses revealed a specific chondrogenic differentiation with the expression of the cartilage specific marker genes Col II, Col X, and aggrecan (AGN) in the TGF-beta1 and the BMP-2 treated group, with earlier expression of these marker genes in the TGF-beta1 treated group. Interestingly, MSC-gels cultured in DMEM with 10% FBS (control) indicated few isolated chondrocyte-like cells but no expression of Col II or Col X could be detected. The results show, that MSCs cultured in a collagen type I hydrogel are able to undergo a distinct chondrogenic differentiation pathway, similar to that described for MSCs cultured in high-density pellet cultures. These findings are valuable in terms of ex vivo predifferentiation or in situ differentiation of MSCs in collagen hydrogels for articular cartilage repair.
    Document Type:
    Reference
    Product Catalog Number:
    MAB8887
    Product Catalog Name:
    Anti-Collagen Type II Antibody, clone 6B3