Sertoli cell-mediated differentiation of male germ cell-like cells from human umbilical cord Wharton's jelly-derived mesenchymal stem cells in an in vitro co-culture system.

BACKGROUND: Microenvironment signals play a critical role in directing the differentiation of stem cells. Sertoli cells (SCs) provide a unique microenvironment that is essential for germ cell differentiation. METHODS: Our previous study has demonstrated that human umbilical cord Wharton's jelly-derived mesenchymal stem cells (HUMSCs) could differentiate towards male germ cells in vitro, but HUMSC-derived germ-like cells expressed only few germ cell markers. The aim of this study was to investigate the effect of SCs on the differentiation of HUMSCs towards male germ cells using a co-culture system that mimicked the in vivo male germ cell microenvironment. RESULTS: HUMSCs formed clump-like features on SC monolayers after seeding for 3 weeks. Differentiated cells formed round colonies that share the morphological features of spermatogonial colonies. RT-PCR, immunofluorescence, confocal microscopy, and Western blot analyses revealed the expression of early germ cell markers STELLA and VASA and male germ cell-specific marker DAZL in differentiated HUMSCs, confirming the presence of cells with characteristics of male germ cells. CONCLUSION: The HUMSC-SC co-culture system mimics a native microenvironment for germ cell colonization without any in vitro artificial manipulation and can be used to explore the mechanisms controlling the differentiation of male germ cells from HUMSCs. Male germ cells derived from HUMSCs may be used in the therapy for male infertility.

Mechanisms of neuroprotection from hypoxia-ischemia (HI) brain injury by up-regulation of cytoglobin (CYGB) in a neonatal rat model.

This study was designed to investigate the expression profile of CYGB, its potential neuroprotective function, and underlying molecular mechanisms using a model of neonatal hypoxia-ischemia (HI) brain injury. Cygb mRNA and protein expression were evaluated within the first 36 h after the HI model was induced using RT-PCR and Western blotting. Cygb mRNA expression was increased at 18 h in a time-dependent manner, and its level of protein expression increased progressively in 24 h. To verify the neuroprotective effect of CYGB, a gene transfection technique was employed. Cygb cDNA and shRNA delivery adenovirus systems were established (Cygb-cDNA-ADV and Cygb-shRNA-ADV, respectively) and injected into the brains of 3-day-old rats 4 days before they were induced with HI treatment. Rats from different groups were euthanized 24 h post-HI, and brain samples were harvested. 2,3,5-Triphenyltetrazolium chloride, TUNEL, and Nissl staining indicated that an up-regulation of CYGB resulted in reduced acute brain injury. The superoxide dismutase level was found to be dependent on expression of CYGB. The Morris water maze test in 28-day-old rats demonstrated that CYGB expression was associated with improvement of long term cognitive impairment. Studies also demonstrated that CYGB can up-regulate mRNA and protein levels of VEGF and increase both the density and diameter of the microvessels but inhibits activation of caspase-2 and -3. Thus, this is the first in vivo study focusing on the neuroprotective role of CYGB. The reduction of neonatal HI injury by CYGB may be due in part to antioxidant and antiapoptotic mechanisms and by promoting angiogenesis.