Growth hormone in the presence of laminin modulates interaction of human thymic epithelial cells and thymocytes in vitro.

BACKGROUND: Several evidences indicate that hormones and neuropeptides function as immunomodulators. Among these, growth hormone (GH) is known to act on the thymic microenvironment, supporting its role in thymocyte differentiation. The aim of this study was to evaluate the effect of GH on human thymocytes and thymic epithelial cells (TEC) in the presence of laminin. RESULTS: GH increased thymocyte adhesion on BSA-coated and further on laminin-coated surfaces. The number of migrating cells in laminin-coated membrane was higher in GH-treated thymocyte group. In both results, VLA-6 expression on thymocytes was constant. Also, treatment with GH enhanced laminin production by TEC after 24 h in culture. However, VLA-6 integrin expression on TEC remained unchanged. Finally, TEC/thymocyte co-culture model demonstrated that GH elevated absolute number of double-negative (CD4(-)CD8(-)) and single-positive CD4(+) and CD8(+) thymocytes. A decrease in cell number was noted in double-positive (CD4(+)CD8(+)) thymocytes. CONCLUSIONS: The results of this study demonstrate that GH is capable of enhancing the migratory capacity of human thymocytes in the presence of laminin and promotes modulation of thymocyte subsets after co-culture with TEC.

Growth hormone in the presence of laminin modulates interaction of human thymic epithelial cells and thymocytes in vitro

BACKGROUND: Several evidences indicate that hormones and neuropeptides function as immunomodulators. Among these, growth hormone (GH) is known to act on the thymic microenvironment, supporting its role in thymocyte differentiation. The aim of this study was to evaluate the effect of GH on human thymocytes and thymic epithelial cells (TEC) in the presence of laminin. RESULTS: GH increased thymocyte adhesion on BSA-coated and further on laminin-coated surfaces. The number of migrating cells in laminin-coated membrane was higher in GH-treated thymocyte group. In both results, VLA-6 expression on thymocytes was constant. Also, treatment with GH enhanced laminin production by TEC after 24 h in culture. However, VLA-6 integrin expression on TEC remained unchanged. Finally, TEC/thymocyte co-culture model demonstrated that GH elevated absolute number of double-negative (CD4-CD8-) and single-positive CD4+ and CD8+ thymocytes. A decrease in cell number was noted in double-positive (CD4+CD8+) thymocytes. CONCLUSIONS: The results of this study demonstrate that GH is capable of enhancing the migratory capacity of human thymocytes in the presence of laminin and promotes modulation of thymocyte subsets after co-culture with TEC.

Effect of busui shengxue granule (see text) on chronic aplastic anemia patients' hematopoietic adhesion molecule VLA-6/CD49f and its ligand laminin.

OBJECTIVE: To observe the effect of Busui Shengxue Granule ((see text) Herbal granule for replenishing marrow to produce blood) on chronic aplastic anemia (CAA) patients' integrin alpha 6 (VLA-6/CD49f) and laminin (Ln). METHODS: Sixty-five patients were divided into experimental group and control group through random number table. There were 34 patients, 17 were male and 17 female, aged 2-67, with a medianage of 30.2 +/- 8.6, in the experimental group, including 17 patients of kidney-yin deficiency and 17 of kidney-yang deficiency, treated by Busui Shengxue Granule. There were 31 patients in the control group, 16 were male and 15 female, aged 4-65, with a medianage of 31.2 +/- 8.0; administered Zaizhang Shengxue Tablet (see text) Herbal tablet for chronic aplastic anemia). Both groups were treated for six months and compared with 10 normal persons after the treatment. Flow cytometry was adopted to detect the change in the expression of VLA-6/CD49f, receptor in mononuclear cells of CAA patients and normal persons. Enzyme-linked immunosorbent assay was applied to detect the expression of peripheral serum Ln. RESULTS: CAA patients' VLA-6/CD49f was in the state of low expression and Ln in the state of high expression. After the treatment, both VLA-6/CD49f and Ln were regulated to some extent and the change in the experimental group was better than that of the control group. Compared with the kidney-yin deficiency patients, those indices of kidney-yang deficiency patients were easier to correct. CONCLUSION: The VLA-6/CD49f and Ln expressions of CAA patients are abnormal. The treatment with Busui Shengxue Granule makes both of them improved.

Endostatin peptide, an inhibitor of angiogenesis, prevents the progression of peritoneal sclerosis in a mouse experimental model.

Peritoneal sclerosis is a major and serious complication in patients on long-term continuous ambulatory peritoneal dialysis (PD). The involvement of angiogenesis and proangiogenic factors such as vascular endothelial growth factor (VEGF)-A in progressing peritoneal sclerosis has been reported. We previously reported the therapeutic efficacy of endostatin peptide, a potent inhibitor of angiogenesis derived from type XVIII collagen, in a mouse diabetic nephropathy model. Here, we examined the therapeutic effect of endostatin peptide in preventing progression in a mouse peritoneal sclerosis model. Male ICR mice received intraperitoneal injections of chlorhexidine gluconate (CG) every other day to induce peritoneal sclerosis. Endostatin peptide (1 or 4 mg/kg/day) was administered via subcutaneously implanted osmotic minipumps. Peritoneal sclerosis (day 24) was significantly suppressed by endostatin peptide in a dose-dependent manner. Peritoneal accumulation of type III collagen was significantly suppressed by endostatin peptide. Increase in the number of CD31(+) blood vessels, F4/80(+) monocyte/macrophage accumulation, and 5-bromodeoxyuridine(+) proliferating cells was significantly inhibited by endostatin peptide. Increase in peritoneal expression of VEGF-A, profibrotic transforming growth factor-beta1, and alpha-smooth muscle actin was suppressed by endostatin peptide. Immunoreactivity for endogenous endostatin (whole molecule) and endostatin receptor alpha5beta1-integrin was increased and colocalized to CD31(+) blood vessels in the thickened peritonea of CG-injected mice. These results demonstrate the potential use of antiangiogenic endostatin peptide as a novel therapeutic agent in preventing peritoneal sclerosis, a severe complication in patients undergoing long-term PD.

A complex containing alpha6beta1-integrin and phosphorylated focal adhesion kinase between Sertoli cells and elongated spermatids during spermatid release from the seminiferous epithelium.

Spermiation is the final step of spermatogenesis and culminates in the disengagement (release) of elongated spermatids from Sertoli cells into the seminiferous tubule lumen. Spermiation failure, wherein spermatids are retained by Sertoli cells instead of releasing, occurs after hormone suppression. The mechanisms involved in spermatid disengagement and retention are not well understood. We previously showed that beta(1)-integrin is associated with spermatids until the point of disengagement, but the ectoplasmic specialisation junction (ES) is not. The aims of this paper are to further characterise the complex that is present immediately prior to spermatid disengagement by identifying the alpha-integrin form dimerised with beta(1)-integrin, localising focal adhesion kinase (FAK) and determining if microtubules are involved. Adult Sprague-Dawley rats received testosterone and oestradiol implants and an FSH antibody for 7 days to suppress testicular testosterone and FSH and induce spermiation failure. Control rats were treated with saline. Immunohistochemical analysis showed that alpha(6)-integrin and a phosphorylated form of FAK (FAK-Tyr(397)) are present between late spermatids and Sertoli cells after ES removal, until the point of disengagement, and both proteins remain associated with retained spermatids after spermiation failure induced by hormone suppression. Using dual-label immunofluorescence, tubulins (and thus microtubules) were observed to co-localise with ES, but were neither associated with elongated spermatids just prior to release nor with retained spermatids following hormone suppression. These results suggest that microtubules are not involved in the final release of spermatids from Sertoli cells. We conclude that spermatid release during spermiation is mediated by a 'disengagement complex' containing alpha(6)beta(1)-integrin and phospho-FAK, the function of which can be affected by gonadotrophin suppression.

Beta1 integrins are distributed in adhesion structures with fibronectin and caveolin and in coated pits.

Integrins are found in adhesion structures, which link the extracellular matrix to cytoskeletal proteins. Here, we attempt to further define the distribution of beta1 integrins in the context of their association with matrix proteins and other cell surface molecules relevant to the endocytic process. We find that beta1 integrins colocalize with fibronectin in fibrillar adhesion structures. A fraction of caveolin is also organized along these adhesion structures. The extracellular matrix protein laminin is not concentrated in these structures. The alpha4beta1 integrin exhibits a distinct distribution from other beta1 integrins after cells have adhered for 1 h to extracellular matrix proteins but is localized in adhesion structures after 24 h of adhesion. There are differences between the fibronectin receptors: alpha5beta1 integrins colocalize with adaptor protein-2 in coated pits, while alpha4beta1 integrins do not. This parallels our earlier observation that of the two laminin receptors, alpha1beta1 and alpha6beta1, only alpha1beta1 integrins colocalize with adaptor protein-2 in coated pits. Calcium chelation or inhibition of mitogen-activated protein kinase kinase, protein kinase C, or src did not affect localization of alpha1beta1 and alpha5beta1 integrins in coated pits. Likewise, the integrity of coated-pit structures or adhesion structures is not required for integrin and adaptor protein-2 colocalization. This suggests a robust and possibly constitutive interaction between these integrins and coated pits.

Alpha 6 beta 1 Integrin is a potential clinical marker for evaluating sperm quality in men.

OBJECTIVE: To determine the clinical significance of alpha6beta1 integrin in human spermatozoa. DESIGN: Prospective case-controlled study. SETTINGS: Hospital infertility clinic in India. PATIENT(S): Sixty-two men undergoing evaluation for infertility and 20 healthy, proven-fertile controls were selected. INTERVENTION(S): Role of alpha6beta1integrin in sperm quality evaluation was determined using semen analysis, cell ELISA, flow cytometry, and in vitro sperm-egg binding. MAIN OUTCOME MEASURE(S): Determination of sperm-associated alpha6beta1 integrin may help in assessing the quality of the human spermatozoa. RESULT(S): Expression of alpha6beta1 integrin was significantly low in the spermatozoa obtained from subfertile men. Only 35%-40% of spermatozoa from fertile men showed a positive reaction to alpha6beta1 antibody. The samples with high rate of acrosomal reaction showed a good expression of alpha6beta1 and maximum binding to oocyte in an in vitro binding assay. CONCLUSION(S): alpha6beta1 Integrin may be used as a clinical marker to evaluate sperm quality.