Distribution Of Laminin Research Articles

Laminin γ1-dependent basement membranes are instrumental to ensure proper olfactory placode shape, position and boundary with the brain, as well as olfactory axon development.

Despite recent progress, the complex roles played by the extracellular matrix in development and disease are still far from being fully understood. Here, we took advantage of the zebrafish sly mutation which affects Laminin γ1, a major component of basement membranes, to explore its role in the development of the olfactory system. Following a detailed characterisation of Laminin distribution in the developing olfactory circuit, we analysed basement membrane integrity, olfactory placode and brain morphogenesis, and olfactory axon development in sly mutants, using a combination of immunochemistry, electron microscopy and quantitative live imaging of cell movements and axon behaviours. Our results point to an original and dual contribution of Laminin γ1-dependent basement membranes in organising the border between the olfactory placode and the adjacent brain: they maintain placode shape and position in the face of major brain morphogenetic movements, they establish a robust physical barrier between the two tissues while at the same time allowing the local entry of the sensory axons into the brain and their navigation towards the olfactory bulb. This work thus identifies key roles of Laminin γ1-dependent basement membranes in neuronal tissue morphogenesis and axon development in vivo .

Atrazine disorganises laminin formation and reduces cell numbers in the tammar testis during early differentiation.

Atrazine, like oestrogen, disorganises laminin formation and reduces the number of germ cells and Sertoli cells in the developing testes of the tammar wallaby. This study suggests that interfering with the balance of androgen and oestrogen affects the integrity of laminin structure and testis differentiation. The herbicide atrazine was banned in Europe in 2003 due to its endocrine disrupting activity but remains widely used. The integrity of the laminin structure in fetal testis cords requires oestrogen signalling but overexposure to xenoestrogens in the adult can cause testicular dysgenesis. However, whether xenoestrogens affect laminin formation in developing testes has not been investigated. Here we examined the effects of atrazine in the marsupial tammar wallaby during early development and compare it with the effects of the anti-androgen flutamide, oestrogen, and the oestrogen degrader fulvestrant. The tammar, like all marsupials, gives birth to altricial young, allowing direct treatment of the developing young during the male programming window (day 20-40 post partum (pp)). Male pouch young were treated orally with atrazine (5 mg/kg), flutamide (10 mg/kg), 17β-oestradiol (2.5 mg/kg) and fulvestrant (1 mg/kg) daily from day 20 to 40 pp. Distribution of laminin, vimentin, SOX9 and DDX4, cell proliferation and mRNA expression of SRY, SOX9, AMH, and SF1 were examined in testes at day 50 post partum after the treatment. Direct exposure to atrazine, flutamide, 17β-oestradiol, and fulvestrant all disorganised laminin but had no effect on vimentin distribution in testes. Atrazine reduced the number of germ cells and Sertoli cells when examined at day 40-50 pp and day 20 to 40 pp, respectively. Both flutamide and fulvestrant reduced the number of germ cells and Sertoli cells. Atrazine also downregulated SRY expression and impaired SOX9 nuclear translocation. Our results demonstrate that atrazine can compromise normal testicular differentiation during the critical male programming window.

Matrix metalloproteinase Nas15 regulates the lumen formation and expansion in Ciona notochord

Lumen formation, as a key process of biological tube construction, is essential in various physiological processes such as nutrient and waste transporting, gas exchanging, and structural supporting. However, the mechanisms underlying tubular lumen development are still not fully understood. In the present study, we identified a matrix metalloproteinase, Nas15, which is enriched in the apical domain of the Ciona embryonic notochord. The expression level of the Nas15 gene significantly increased during notochord lumen formation and expansion. Nas15 loss-of-function resulted in abnormal notochord lumen expansion in Ciona embryos. Besides, yeast two-hybrid screening and CO-IP results indicated a Phosphatase 2 Catalytic Subunit Alpha (PPP2CA) physically interacted with Nas15. PPP2CA also involved in notochord lumen formation via localizing Nas15. Furthermore, we investigated the distribution of laminin in Nas15 disrupted embryos. In conclusion, our results revealed a mechanisms of how notochord cells regulating lumen expansion via metalloproteinase-mediated ECM localization. This findings provide insight into the mechanisms of tubular organ lumen formation and serve as a reference for research on human abnormal lumenogenesis diseases.

The Effect of Chrysin on the Distribution of Extracellular Matrix Proteins around Leydig Cells under Heat Stress Injury

Objective. In the testicular tissue stroma, matrix proteins such as laminin and fibronectin play a critical role in transmitting signals under normal and stressful conditions to Leydig cells. Heat stress is considered one of the stressful conditions in the testicular tissue. This study has investigated the protective effects of chrysin on the distribution of laminin and fibronectin around Leydig cells under heat stress. Methods. Rats were divided into four groups, including sham (A), heat stress (B), heat stress with chrysin treatment (50 mg/kg) (C), and heat stress with chrysin treatment (75 mg/kg) (D). At the end of the treatment period, on the 21st day, testosterone serum levels were evaluated, and the testes were also assessed to determine the changes in gene expression and distribution of laminin, fibronectin, and caspase-3 proteins. Results. Exposure to heat stress in Group B resulted in increased levels of caspase-3, decreased activity, height, and diameter of seminiferous tubules, and altered distribution of laminin and fibronectin proteins around the Leydig cells when compared to the sham group (p<0.05). Treatment with chrysin 75 resulted in a significant decrease in caspase-3 levels, improved testosterone levels, and increased distribution of laminin and fibronectin around Leydig cells compared to group B (p<0.05). In addition, the group treated with chrysin 75 showed improved seminiferous histological activity markers in comparison to group B (p<0.05). Conclusion. Following heat stress, concurrent with disrupted steroidogenesis, an evident change happens in the distribution pattern of the extracellular matrix (ECM) proteins of the testis, which may indicate the transmission of stress signals from the ECM to the Leydig cells. Treatment of chrysin in 75 mg/kg dose can reduce the damage caused by heat stress on the ECM and Leydig cells.

Exogenous laminin exhibits a unique vascular pattern in the brain via binding to dystroglycan and integrins

BackgroundUnlike other proteins that exhibit a diffusion pattern after intracerebral injection, laminin displays a vascular pattern. It remains unclear if this unique vascular pattern is caused by laminin-receptor interaction or laminin self-assembly.MethodsWe compared the distribution of various wild-type laminin isoforms in the brain after intracerebral injection. To determine what causes the unique vascular pattern of laminin in the brain, laminin mutants with impaired receptor-binding and/or self-assembly activities and function-blocking antibodies to laminin receptors were used. In addition, the dynamics of laminin distribution and elimination were examined at multiple time points after intracerebral injection.ResultsWe found that β2-containing laminins had higher affinity for the vessels compared to β1-containing laminins. In addition, laminin mutants lacking receptor-binding domains but not that lacking self-assembly capability showed substantially reduced vascular pattern. Consistent with this finding, dystroglycan (DAG1) function-blocking antibody significantly reduced the vascular pattern of wild-type laminin-111. Although failed to affect the vascular pattern when used alone, integrin-β1 function-blocking antibody further decreased the vascular pattern when combined with DAG1 antibody. EDTA, which impaired laminini-DAG1 interaction by chelating Ca2+, also attenuated the vascular pattern. Immunohistochemistry revealed that laminins were predominantly located in the perivascular space in capillaries and venules/veins but not arterioles/arteries. The time-course study showed that laminin mutants with impaired receptor-engaging activity were more efficiently eliminated from the brain compared to their wild-type counterparts. Concordantly, significantly higher levels of mutant laminins were detected in the cerebral-spinal fluid (CSF).ConclusionsThese findings suggest that intracerebrally injected laminins are enriched in the perivascular space in a receptor (DAG1/integrin)-dependent rather than self-assembly-dependent manner and eliminated from the brain mainly via the perivascular clearance system.

Structural and Functional Abnormalities in the Spleen of anmFtz-F1 Gene–Disrupted Mouse

AbstractThe spleen has two main functions. The first is to provide a proper microenvironment to lymphoid and myeloid cells, whereas the second involves clearance of abnormal erythrocytes. Ad4BP/SF-1, a product of the mammalian FTZ-F1 gene (mFTZ-F1), was originally identified as a steroidogenic, tissue-specific transcription factor. Immunohistochemical examination of the mammalian spleens confirmed the expression of Ad4BP/SF-1 in endothelial cells of the splenic venous sinuses and pulp vein. In mFtz-F1 gene–disrupted (KO) mice, several structural abnormalities were detected in the spleen, including underdevelopment and nonuniform distribution of erythrocytes. Examination of the spleen of KO fetuses showed failure of development of certain tubular structures during embryogenesis. These structures are normally assembled by Ad4BP/SF-1 immunoreactive cells, and most likely form the vascular system during later stages of development. Other structural abnormalities in the spleen of the KO mice included defects in the tissue distribution of type-IV collagen, laminin, c-kit, and vimentin. These morphologic defects in the vascular system were associated with a decrease in the proportion of hematopoietic cells, although differentiation of these cells was not affected significantly. A high number of abnormal red blood cells containing Howell-Jolly bodies were noted in the KO mice, indicating impaired clearance by the splenic vascular system. We also detected the presence of an mRNA-encoding cholesterol side-chain cleavage P450 in the spleen, resembling the findings in steroidogenic tissues such as the gonads and adrenal cortex. The mRNA transcript was not involved in splenic structural defects as it was detected in the spleens of both normal and KO mice, indicating that the regulatory mechanism of theP450 gene in the spleen is different from that in steroidogenic tissues. Our results indicate that a lack of the mFtz-F1 gene in mice is associated with structural and functional abnormalities of the splenic vascular system.

Protective effects of alpha-lipoic acid on diazinon-induced renal toxicity in rats: an immunohistochemistry study

The current study aimed to examine the impacts of alpha-lipoic acid (ALA) on oxidative stress parameters and the expression of fibronectin and laminin in the renal corpuscle of male Wistar rats following exposure to diazinon (DZN). The animals were distributed into the following groups: control, DZN (40 mg/kg), DZN + ALA (40 mg/kg + 100 mg/kg), ALA (100 mg/kg), and sham. Diazinon induced lipid peroxidation and oxidative stress and reduced the distribution and mRNA expression of laminin and fibronectin. ALA reduces the nephrotoxic effects of diazinon. In conclusion, ALA plays a therapeutic role in the treatment of oxidative stress-associated toxicities and diseases.

The protective role of alpha-lipoic acid on the appearance of fibronectin and laminin in renal tubules following diazinon exposure: An experimental immunohistochemical study

Extracellular matrix (ECM) exerts a major role in maintaining the structure and developmental processes of tissues. To form the tubular basement membrane in the kidney, sulfate proteoglycans, collagen, laminin, fibronectin, and other glycoproteins congregate in the ECM. As an insecticide, diazinon (DZN) may alter the proportion of ECM by cholinesterase activity inhibition and oxidative stress. The naturally, alpha-lipoic acid (ALA) plays an effective and therapeutic role in the treatment of toxicities and diseases in the body. In the current study, an attempt was made to evaluate the impacts of alpha-lipoic acid on the distribution of fibronectin and laminin in the renal tubules of male Wistar rats following exposure to diazinon. In this study, the animal groups comprised 30 adult male Wistar rats (almost three months old) randomly distributed into the following groups; control, DZN (40 mg/kg), DZN + ALA (40 mg/kg+100 mg/kg), ALA (100 mg/kg), and sham. The rats were anesthetized after six weeks. Blood sampling was performed, and kidneys were removed for immunohistochemistry study. Diazinon reduced the distribution of fibronectin and laminin and significantly inhibited cholinesterase activity in the renal tubules. Furthermore, urea and creatinine levels were higher in diazinon than in other groups. ALA in the co-treatment group enhanced cholinesterase activity and distribution of both glycoproteins in the renal tubules. Urea and creatinine levels were meaningfully diminished in the DZN + ALA group. The nephrotoxic effect of diazinon in vivo was the reduced distribution of laminin and fibronectin, probably induced by cholinesterase activity inhibition. As an antioxidant with specific properties, ALA reduces the nephrotoxic effects of diazinon by multifarious mechanisms.

Hedgehog Signaling Regulates Epithelial Morphogenesis to Position the Ventral Embryonic Midline.

Despite much progress toward understanding how epithelial morphogenesis is shaped by intra-epithelial processes including contractility, polarity, and adhesion, much less is known regarding how such cellular processes are coordinated by extra-epithelial signaling. During embryogenesis, the coelomic epithelia on the two sides of the chick embryo undergo symmetrical lengthening and thinning, converging medially to generate and position the dorsal mesentery (DM) in the embryonic midline. We find that Hedgehog signaling, acting through downstream effectors Sec5 (ExoC2), an exocyst complex component, and RhoU (Wrch-1), a small GTPase, regulates coelomic epithelium morphogenesis to guide DM midline positioning. These effects are accompanied by changes in epithelial cell-cell alignment and N-cadherin and laminin distribution, suggesting Hedgehog regulation of cell organization within the coelomic epithelium. These results indicate a role for Hedgehog signaling in regulating epithelial morphology and provide an example of how transcellular signaling can modulate specific cellular processes to shape tissue morphogenesis.

Laminin-Inspired Cell-Instructive Microenvironments for Neural Stem Cells.

Laminin is a heterotrimeric glycoprotein with a key role in the formation and maintenance of the basement membrane architecture and properties, as well as on the modulation of several biological functions, including cell adhesion, migration, differentiation and matrix-mediated signaling. In the central nervous system (CNS), laminin is differentially expressed during development and homeostasis, with an impact on the modulation of cell function and fate. Within neurogenic niches, laminin is one of the most important and well described extracellular matrix (ECM) proteins. Specifically, efforts have been made to understand laminin assembly, domain architecture, and interaction of its different bioactive domains with cell surface receptors, soluble signaling molecules, and ECM proteins, to gain insight into the role of this ECM protein and its receptors on the modulation of neurogenesis, both in homeostasis and during repair. This is also expected to provide a rational basis for the design of biomaterial-based matrices mirroring the biological properties of the basement membrane of neural stem cell niches, for application in neural tissue repair and cell transplantation. This review provides a general overview of laminin structure and domain architecture, as well as the main biological functions mediated by this heterotrimeric glycoprotein. The expression and distribution of laminin in the CNS and, more specifically, its role within adult neural stem cell niches is summarized. Additionally, a detailed overview on the use of full-length laminin and laminin derived peptide/recombinant laminin fragments for the development of hydrogels for mimicking the neurogenic niche microenvironment is given. Finally, the main challenges associated with the development of laminin-inspired hydrogels and the hurdles to overcome for these to progress from bench to bedside are discussed.

Inhibition of mmp13a during zebrafish fin regeneration disrupts fin growth, osteoblasts differentiation, and Laminin organization.

Matrix metalloproteinases 13 (MMP13) is a potent endopeptidase that regulate cell growth, migration, and extracellular matrix remodeling. However, its role in fin regeneration remains unclear. mmp13a expression is strongly upregulated during blastema formation and persists in the distal blastema. mmp13a knockdown via morpholino electroporation impairs regenerative outgrowth by decreasing cell proliferation, which correlates with a downregulation of fgf10a and sall4 expression in the blastema. Laminin distribution in the basement membrane is also affected in mmp13a MO-injected rays. Another impact of mmp13a knockdown is observed in the skeletal elements of the fin rays. Expression of two main components of actinotrichia, Collagen II and Actinodin 1 is highly reduced in mmp13a MO-injected rays leading to highly disorganized actinotrichia pattern. Inhibition of mmp13a strongly affects bone formation as shown by a reduction of Zns5 and sp7 expression and of bone matrix mineralization in rays. These defects are accompanied by a significant increase in apoptosis in mmp13a MO-injected fin regenerates. Defects of expression of this multifunctional proteinase drastically affects osteoblast differentiation, bone and actinotrichia formation as well as Laminin distribution in the basement membrane of the fin regenerate, suggesting the important role of Mmp13 during the regenerative process.

Basement membranes in the kidney of the dromedary camel (Camelus dromedarius): An immunohistochemical and ultrastructural study

Basement membranes consist of various proteins, the major ones being laminin and collagen type IV. Primary defects in these two proteins have been extensively associated with kidney pathologies. This study aimed to establish baseline information on the immunohistochemical distribution of laminin and collagen type IV, and to corelate these with the ultrastructure of basal laminae in the uriniferous tubules of the dromedary camel. Tissue samples were taken from the kidneys of eight adult female camels, and processed for immunohistochemical and ultrastructural investigations. Strong intensity of collagen type IV was observed within the basement membranes of Bowman’s capsule. The thickness of the basal lamina of the parietal layer of Bowman's capsule varied extensively depending on the region of the renal corpuscle; the thicker areas were always associated with cuboidal epithelial cells. The glomerular basement membrane revealed strong immunostaining of laminin, whereas the mesangial matrix was strongly immunoreactive to collagen type IV. Abundant amount of laminin was found in the basement membranes of proximal convoluted tubules, thin limbs of the loop of Henle, and collecting ducts. Dense immunostainings of laminin and collagen type IV were observed in the medullary regions of uriniferous tubule, in which numerous projections extended from the basal laminae into the subjacent connective tissue. Overall, the present study revealed marked variations in the distribution of the basement membrane markers laminin and collagen type IV in the uriniferous tubules of camel kidney. The results have also shown difference in the thickness of basal laminae. This variation in thickness, however, was unlikely to be influenced by the amount of laminin and collagen type IV.

Spatial and temporal changes in extracellular elastin and laminin distribution during lung alveolar development

Lung alveolarization requires precise coordination of cell growth with extracellular matrix (ECM) synthesis and deposition. The role of extracellular matrices in alveogenesis is not fully understood, because prior knowledge is largely extrapolated from two-dimensional structural analysis. Herein, we studied temporospatial changes of two important ECM proteins, laminin and elastin that are tightly associated with alveolar capillary growth and lung elastic recoil respectively, during both mouse and human lung alveolarization. By combining protein immunofluorescence staining with two- and three-dimensional imaging, we found that the laminin network was simplified along with the thinning of septal walls during alveogenesis, and more tightly associated with alveolar endothelial cells in matured lung. In contrast, elastin fibers were initially localized to the saccular openings of nascent alveoli, forming a ring-like structure. Then, throughout alveolar growth, the number of such alveolar mouth ring-like structures increased, while the relative ring size decreased. These rings were interconnected via additional elastin fibers. The apparent patches and dots of elastin at the tips of alveolar septae found in two-dimensional images were cross sections of elastin ring fibers in the three-dimension. Thus, the previous concept that deposition of elastin at alveolar tips drives septal inward growth may potentially be conceptually challenged by our data.

Immunohistochemical Evaluation of the Effects of Nitrate in Drinking Water on Laminin Alpha-5 Expression in Rat Renal Glomeruli

Background: Nitrate is a polyatomic ion with the molecular formula NO3-. Nitrate poisoning occurs through metabolism in the liver and conversion of nitrate to nitrite, which acts as an intermediary. Laminins are high-molecular weight proteins in extracellular matrix, regarded as one of the major components of the basement membrane. Objectives: The current study aimed to evaluate the effects of nitrate on laminin α5 expression in rat renal glomeruli. Methods: The current interventional study was conducted on 24 male Wistar rats in Iran during 2014 - 2016. Samples were randomly divided into four groups as follows: 1) Normal drinking water, 2) Distilled water containing 45 mg/L of nitrate, 3) Distilled water containing 100 mg/L of nitrate and 4) Distilled water (control). Sample size consisted of 48 kidneys randomly collected from rats. Laminin α5 content in renal glomeruli was determined using the immunohistochemistry (IHC) protocol. Data analysis was performed using the Kruskal-Wallis test and the Spearman correlation coefficient; P value below 0.05 was considered statistically significant. Results: In the study, intensity of reaction to anti-laminin was not the same in renal glomeruli. While there was no significant difference between the groups one and two (P > 0.05), a significant difference was observed between the groups three and four (P < 0.05) in this regard. Conclusions: According to the results of the study, standard amount of nitrate in drinking water had no significant impact on laminin content. On the other hand, exceeded nitrate concentrations limited the distribution of laminin, leading to potential adverse effects on glomerular basement membrane.

Laminin-111 Inhibits Bovine Fertilization but Improves Embryonic Development invitro, and Receptor Integrin-β1 is Involved in Sperm-Oocyte Binding.

This study detected the distribution of laminin during embryonic formation by immunofluorescence. To determine the possible function of laminin on developmental ability of invitro fertilized embryos, the presumptive zygotes were divided and transferred to CR1aa medium supplemented with different concentrations (0μg/ml, 5μg/ml, 10μg/ml and 20μg/ml) of laminin. To explore the association with sperm-oocyte fusion, oocytes and/or sperm were pre-incubated with laminin or anti-β1 antibody before insemination. Laminin was absent in mature oocytes and could be detected first at the 8-cell stage and then displayed an increasing tendency. Adding 10μg/ml laminin to the culture medium improved embryonic development including cleavage rate, blastocyst rate, total cell numbers in the blastocyst and cell numbers in the inner cell mass. Laminin inhibited sperm-oocyte fusion when incubated with oocytes and/or sperm before invitro fertilization, and only integrin-β1 of sperm was involved in sperm-oocyte binding. Inhibition may be caused by blocking β1, but why laminin inhibits fertilization is still unknown. The results suggest that laminin plays an important role during embryonic formation and has a negative function in sperm-oocyte fusion, but improves embryonic development. However, only integrin-β1 is involved in sperm-oocyte binding.

Using human epithelial amnion cells in human de-epidermized dermis for skin regeneration

BackgroundHuman amniotic epithelial cells (hAECs) is a desirable reserve of stem cells. Human de-epidermized dermis (DED) retains basic tissue structure and parts of the basement membrane (BM) components at the acelluIar dermal surface, and provides a potential tool for skin regeneration. ObjectiveTo evaluate the potential role of hAECs in skin regeneration, we used DED to perform organotypic culture of hAECs to develop organotypic skin. MethodsHAECs were isolated and cultured. Biological characteristics of hAECs were determined by immunocytochemistry and flow cytometry. To prepare DED, the epidermis was removed and then repeated freeze-thaw cycles. HAECs and fibroblast were seeded onto DED to perform the submerged culture for 3 days and then to be maintained at the air-liquid interface for 14 days to form organotypic culture. To identify whether the obtained DED retain the BM structure and components, the histological characteristics of DED and the BM were detected by immunohistochemistry. To evaluate whether the organotypic skin has similar histological characteristics with normal human skin, the marks of epidermal proliferation and differentiation and basement membrane component were detected by immunohistochemistry. Moreover, cell ultrastructure, cell–cell contact and ultrastructure of BM were examined under the transmission electron microscopy. ResultsHAECs has stem-cell characteristics with strong pluripotent Oct-4 and embryonic marker SSEA-4 expression. DED has effectively cleansed the cell components and continuous distributions of laminin and collagen IV. The histological appearance of tissue-engineered skin in vitro has 4 to 9 continuous layers of stratified epithelium and is similar to normal human skin in morphology. Immunohistochemical studies revealed that proliferation and differentiation markers such as Ki67, CK19, CK14, CK10, filaggrin but not CK18 expressed similar pattern characteristics to normal human epidermis. In addition, Periodic acid-Schiff stain showed that a uniform red staining strip located at the epidermal-dermal junction. BM component proteins (type IV collagen and laminin) and cell adhesion protein (desmoglein) were detected by immunohistochemistry in organotypic skin. Ultrastructurally, desmosomes, hemidesmosomes and BM zone (BMZ) were observed in organotypic skin. ConclusionsOur studies indicate that the hAECs is a promising stem cell source for tissue-engineered skin, and DED with hAECs is a potential application prospects in regenerative medicine.

Collagen Type IV and Laminin Expressions during Cartilage Repair and in Late Clinically Failed Repair Tissues from Human Subjects.

ObjectiveTo identify the collagen type IV (Col4) isoform in articular cartilage and to evaluate the expressions of Col4 and laminin in the pericellular matrix (PCM) in damaged cartilage and during cartilage repair.DesignThe Col4 isoform was determined in chondrocytes isolated from 6 patients cultured up to 6 days and in 21% O2 or 1% O2, and the gene expression of Col4 α-chains was investigated. The distribution of Col4 and laminin in traumatically damaged cartilage (n = 7) and clinically failed cartilage repair (microfracture, TruFit, autologous chondrocyte implantation; n = 11) were investigated using immunohistochemistry. Normal human cartilage was used as control (n = 8). The distribution during clinical cartilage repair procedures was investigated in a minipig model with 6-month follow-up (untreated chondral, untreated osteochondral, microfracture, autologous chondrocyte implantation; n = 10).ResultsThe Col4 isoform in articular cartilage was characterized as α1α1α2, which is an isoform containing antiangiogenic domains in the NC1-terminals (arresten and canstatin). In normal cartilage, laminin and Col4 was exclusively found in the PCM. High amounts (>50%) of Col4 in the PCM significantly decreased in damaged cartilage (P = 0.004) and clinically failed repair tissue (P < 0.001). Laminin was only found with high expression (>50%) in 4/8 of the normal samples, which was not statistically significantly different from damaged cartilage (P = 0.15) or failed cartilage repair (P = 0.054).ConclusionsCol4 in cartilage contain antiangiogenic domains and may play a role in the hypoxic environment in articular cartilage. Col4 and laminin was not found in the PCM of damaged and clinically failed repair.

Effects of ECM protein micropatterns on the migration and differentiation of adult neural stem cells.

The migration and differentiation of adult neural stem cells (aNSCs) are believed to be strongly influenced by the spatial distribution of extracellular matrix (ECM) proteins in the stem cell niche. In vitro culture platform, which involves the specific spatial distribution of ECM protein, could offer novel tools for better understanding of aNSC behavior in the spatial pattern of ECM proteins. In this work, we applied soft-lithographic technique to design simple and reproducible laminin (LN)-polylysine cell culture substrates and investigated how aNSCs respond to the various spatial distribution of laminin, one of ECM proteins enriched in the aNSC niche. We found that aNSC preferred to migrate and attach to LN stripes, and aNSC-derived neurons and astrocytes showed significant difference in motility towards LN stripes. By changing the spacing of LN stripes, we were able to control the alignment of neurons and astrocytes. To the best of our knowledge, this is the first time to investigate the differential cellular responses of aNSCs on ECM protein (LN) and cell adhesive synthetic polymer (PDL) using surface micropatterns. Our findings would provide a deeper understanding in astrocyte-neuron interactions as well as ECM-stem cell interactions.

Leptospira interrogans enters different host cells by binding to distinct molecules in the extracellular matrix

Leptospirosis caused by Leptospira is a worldwide zoonotic disease. The 2 spirochete can efficiently invade host cells and spread from blood into internal organs, but the mechanisms of leptospiral internalization into different host cells remain poorly understood. Adhesion of leptospires to the ECM (extracellular matrix) initiated leptospire internalization in macrophage cell-lines THP-1, J774A.1, and in human umbilical epithelial cells (HUVEC). We assessed the distribution of ECM , including fibronectin (FN), laminin and collagens 1-4 (COL1-COL4) in different cells. FN was expressed in THP-1 and J774A.1 cells, and FN, LN, COL3 and COL4 were expressed in HUVEC. Then, we found leptospires adhered to FN, LN, COL3 and COL4. The most important intracellular leptospires in macrophages (THP-1 and J774A) significantly decreased when leptospires were pre-blocked with FN This indicates that FN has an important role in the adherence to and entry of leptospires in macrophages, while in HUVEC, FN, LN, COL3 and COL4 assume this role.

Ultrastructural immunolocalization of laminin 332 (laminin 5) at dento-gingival interface in Macaca fuscata monkey.

Although laminin 332 (laminin 5), an extracellular matrix molecule involved in cell adhesion and migration, has been localized at the interface between the tooth enamel and junctional epithelium, its ultrastructural localization remains to be fully clarified. The purpose of the present study was to investigate the ultrastructural distribution of laminin 332 at the dento-gingival interface in Japanese monkey (Macaca fuscata) using pre- and post-embedding immunoelectron microscopy. Pre-embedding immunoelectron microscopy revealed a broad band of internal basal lamina together with supplementary lamina densa, and both showed immunolabeling for laminin 332. Immunoreaction products for laminin 332 were observed in the rough-surfaced endoplasmic reticulum of the junctional epithelial cells close to the tooth enamel. Post-embedding immunoelectron microscopy revealed an increase in the number of immunogold particles toward the coronal portion, resulting in a large accumulation of particles on the basal lamina, preferentially on the lamina densa. Concomitantly the dental cuticle at the dento-gingival interface was sporadically, but specifically, immunogold-labeled with anti-laminin 332 antibody. These data suggest that junctional epithelium actively produces laminin 332, and that the products accumulate at the dento-gingival interface during cell migration coronally towards the gingival sulcus.