Regulation of blood-testis barrier dynamics by the mTORC1/rpS6 signaling complex: An in vitro study / 亚洲男科学杂志(英文版)

During spermatogenesis, developing germ cells that lack the cellular ultrastructures of filopodia and lamellipodia generally found in migrating cells, such as macrophages and fibroblasts, rely on Sertoli cells to support their transport across the seminiferous epithelium. These include the transport of preleptotene spermatocytes across the blood-testis barrier (BTB), but also the transport of germ cells, in particular developing haploid spermatids, across the seminiferous epithelium, that is to and away from the tubule lumen, depending on the stages of the epithelial cycle. On the other hand, cell junctions at the Sertoli cell-cell and Sertoli-germ cell interface also undergo rapid remodeling, involving disassembly and reassembly of cell junctions, which, in turn, are supported by actin- and microtubule-based cytoskeletal remodeling. Interestingly, the underlying mechanism(s) and the involving biomolecule(s) that regulate or support cytoskeletal remodeling remain largely unknown. Herein, we used an in vitro model of primary Sertoli cell cultures that mimicked the Sertoli BTB in vivo overexpressed with the ribosomal protein S6 (rpS6, the downstream signaling protein of mammalian target of rapamycin complex 1 [mTORC1]) cloned into the mammalian expression vector pCI-neo, namely, quadruple phosphomimetic and constitutively active mutant of rpS6 (pCI-neo/p-rpS6-MT) versus pCI-neo/rpS6-WT (wild-type) and empty vector (pCI-neo/Ctrl) for studies. These findings provide compelling evidence that the mTORC1/rpS6 signal pathway exerted its effects to promote Sertoli cell BTB remodeling. This was mediated through changes in the organization of actin- and microtubule-based cytoskeletons, involving changes in the distribution and/or spatial expression of actin- and microtubule-regulatory proteins.

Protection of hypothermic preserved isolated rat hearts by resveratrol and its underlying mechanism / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate whether resveratrol (RES) plays a protective role in hypothermic preserved isolated rat hearts and whether it is mediated by regulation of silent information regulator protein-1 (Sirt-1) expression.</p><p><b>METHODS</b>The Langendorff model of isolated rat heart was used. After stored in different Celsior solution at 4 degrees C for 9 h, SD rat hearts were randomly divided into 7 groups: blank control group;9 h group (soley hypothermic preservation for 9 h); RES group (3, 10, 30 micromol/L RES treatment plus hypothermic preservation for 9 h ), niacinamide (NAM) group (40 micromol/L NAM added in Celsior solution plus hypothermic preservation for 9 h), RES + NAM group (30 micromol/L RES and 40 micromol/L NAM were added in Celsior solution plus hypothermic preservation for 9 h). The morphological changes of cardiomyocytes were detected by the HE staining with the light microscope. The mRNA and protein expression levels of Sirt-1 were detected by Real-Time PCR and Western blot respectively.</p><p><b>RESULTS</b>(1) Compared with the blank control group, myocardiocytes were injured remarkably in the 9 h group and the Sirt-1 mRNA and protein expression levels were decreased significantly (P < 0.01); (2) Compared with the 9 h group, rat myocardial injury was alleviated gradually in 3, 10, 30 micromol/L RES group and the Sirt-1 mRNA and protein expression levels were increased in a dose-dependent manner (P < 0.05); (3) The above protective effects of RES were attenuated by Sirt-1 inhibitor NAM.</p><p><b>CONCLUSION</b>RES can protect myocardiocytes from injury caused by long range hypothermic preservation and this protective effect maybe mediated by upregulation of Sirt-1 expression.</p>