Gene expression changes of urokinase plasminogen activator and urokinase receptor in rat testes at postnatal stages

Aim： To investigate the gene expression changes of urokinase plasminogen activator （uPA）/urokinase receptor （uPAR） in rat testes at postnatal stages and explore the effects of uPA/uPAR system on the rat spermatogenesis. Methods： The mRNAs of uPA and uPAR in rat testes were measured by using real-time quantitative polymerase chain reaction （PCR） at postnatal days 0, 5, 10, 15, 21, 28, 35, 42, 49 and 56, respectively. Results： The tendencies of uPA and uPAR mRNA expression were similar at most postnatal stages except for Do. The expression of uPAR mRNA in rats testes was relatively higher than that of uPA at postnatal Do, and both were decreased until D21, increased obviously at postnatal D28, reached a peak at postnatal D35, then declined sharply at postnatal D42 and retained at a low level afterwards. Conclusion： The uPA/uPAR system may be strongly linked to spermiation and spermatogenesis via regulating germ cell migration and proliferation, as well as promoting the spermiation and detached residual bodies from the mature spermatids.

Urokinase Receptor Gene Expression Inhibited by siRNA Cocktails in Co-culture of Spermatogenic Cells with Sertoli Cells from 3-Week-Old Rat

Objective To study the functions of urokinase receptor （uPAR） during spermatogenesis by adding targeted siRNA cocktails to the co-culture of Sertoli cell with spermatogenic cells. Methods The seminiferous tubule samples from SD rats aged 20-23 d were digested with collagenase for 15-20 rain, then were cut into smaU fragments. Tubular fragments were digested with collagenase again for 5 -10 min, then gently resuspended in F12/ DMEM supplemented with vitamins and hormones. Cell samples were seeded in plate and cultured at 32 ℃ for 2 weeks. After 48 h, siRNA cocktails at a concentration of 15 nmol/L or 30 nmol/L were introduced into this cocultured Sertoli/spermatogenic cells. After then for 48 h, expression of uPAR mRNA was analyzed by real-time RT-PCR. Results Some spermatogenic cells took place morphologic changes and generated an obvious flagellum. The expression levels of uPAR mRNA silencing with siRNA cocktails at a concentration of 15 nmol/L or 30 nmol/L were significantly lower than those in nontransfected group （P〈0.05）; the inhibition rate was 63.5% or 76.7%, respectively. Conclusion The meiosis and spermiogenesis could take place in this culture system, and the siRNA cocktails can effectively inhibit the gene expression of uPAR in co-cultured Sertoli/spermatogenic cells.

Elevation of serum urokinase plasminogen activator receptor and liver stiffness in postoperative biliary atresia

AIMTo investigate serum urokinase-type plasminogen activator receptor (uPAR) and liver stiffness in biliary atresia (BA) and examine the correlation of circulating uPAR, liver stiffness, and clinical outcomes in postoperative BA children. METHODSEighty-five postKasai BA children and 24 control subjects were registered. Circulating uPAR was measured using enzyme-linked immunosorbent essay. Liver stiffness was analyzed using transient elastography. RESULTSBA children had significantly greater circulating uPAR and liver stiffness scores than control subjects (P P r = 0.507, P r = 0.364, P r = 0.559, P r = 0.325, P r = 0.508, P CONCLUSIONCirculating uPAR and liver stiffness values were greater in BA children than healthy controls. The increased circulating uPAR was associated with liver dysfunction in BA. As a consequence, serum uPAR and liver stiffness may be used as noninvasive biomarkers indicating the progression of liver fibrosis in postKasai BA.

Primary focal and segmental glomerulosclerosis and soluble factor urokinase-type plasminogen activator receptor

Primary focal and segmental glomerulosclerosis(FSGS) may be due to genetic or acquired etiologies and is a common cause of nephrotic syndrome with high morbidity that often leads to end-stage renal failure. The different available therapeutic approaches are unsuccessful, in part due to partially deciphered heterogeneous and complex pathophysiological mechanisms. Moreover, the term FSGS, even in its primary form, comprises a histological description shared by a number of different causes with completely different molecular pathways of disease. This review focuses on the latest developments regarding the pathophysiology of primary acquired FSGS caused by soluble factor urokinase type plasminogen activator receptor, a circulating permeability factor involved in proteinuria and edema formation, and describes recent advances with potential success in therapy.

The uPA/uPAR system in astrocytic wound healing

The repair of injured tissue is a highly complex process that involves cell prolife ration,differentiation,and migration.Cell migration requires the dismantling of intercellular contacts in the injured zone and their subsequent reconstitution in the wounded area.Urokinase-type plasminogen activator(u PA)is a serine proteinase found in multiple cell types including endothelial cells,smooth muscle cells,monocytes,and macrophages.A substantial body of experimental evidence with different cell types outside the central nervous system indicates that the binding of uPA to its receptor(uPAR)on the cell surface prompts cell migration by inducing plasmin-mediated degradation of the extracellular matrix.In contrast,although uPA and uPAR are abundantly found in astrocytes and u PA binding to uPAR triggers astrocytic activation,it is unknown if uPA also plays a role in astrocytic migration.Neuronal cadherin is a member of cell adhesion proteins pivotal for the formation of cell-cell conta cts between astrocytes.More specifically,while the extracellular domain of neuronal cadherin interacts with the extracellular domain of neuronal cadherin in neighboring cells,its intracellular domain binds toβ-catenin,which in turn links the complex to the actin cytos keleton.Glycogen synthase kinase 3βis a serine-threonine kinase that prevents the cytoplasmic accumulation ofβ-catenin by inducing its phosphorylation at Ser33,Ser37,and Ser41,thus activating a sequence of events that lead to its proteasomal degradation.The data discussed in this perspective indicate that astrocytes release u PA following a mechanical injury,and that binding of this u PA to uPAR on the cell membrane induces the detachment ofβ-catenin from the intracellular domain of neuronal cadherin by triggering its extracellular signal-regulated kinase 1/2-mediated phosphorylation at Tyr650.Remarkably,this is followed by the cytoplasmic accumulation ofβ-catenin because uPA-induced extracellular signalregulated kinase 1/2 activation also phosphorylates lipoprotein receptor-related protein 6 at Ser1490,which in turn,by recruiting glycogen synthase kinase 3βto its intracellular domain abrogates its effect onβ-catenin.The cytoplasmic accumulation ofβ-catenin is followed by its nuclear translocation,where it induces the expression of uPAR,which is required for the migration of astrocytes from the injured edge into the wounded area.

Bioactive proteins in healthy pregnancies and preeclampsia： relevance to hypertension and proteinuria

Background Bioactive proteins, such as cytokines and chemokines, have not been systematically evaluated in healthy and preeclamptic pregnancies. We aimed to investigate the difference of these proteins between healthy and preeclamptic pregnancies in order to help clarify their potential roles in the pathogenesis of hypertension and proteinuria in preeclampsia. Methods Samples of amniotic fluid and maternal/umbilical cord blood were collected from normal pregnancies and women with preeclampsia for examination of bioactive proteins. Fifty-three pregnant women were enrolled in this study. Of them, 30 pregnant women were recruited as healthy controls, and 23 pregnant women were diagnosed with preeclampsia. An antibody array was used to screen for higher levels of cytokines and related proteins in amniotic fluid than in the blood samples, and these proteins were then selected for quantification by immunoassay. Results Interleukin-1 receptor 4, hepatocyte growth factor, and urokinase plasminogen activator receptor were significantly elevated in the blood of preec^ampsia patients. In particular, intedeukin-1 receptor 4 was 8-fold higher in preeclampsia patients than in the healthy pregnancies. Moreover, in cord blood samples hepatocyte growth factor and interleukin-8 were significantly higher in preeclampsia patients. Conclusions Because of the biologic activities, Interleukin-1 receptor 4, hepatocyte growth factor, urokinase plasminogen activator receptor and interleukin-8 in maternal and/or cord blood could play a role in the pathogenesis of hypertension and proteinuria in preeclampsia.