Embryonic germ cells as well as germline stem cells from neonatal mouse testis are pluripotent and have differentiation potential similar to embryonic stem cells, suggesting that the germline lineage may retain the ability to generate pluripotent cells. However, until now there has been no evidence for the pluripotency and plasticity of adult spermatogonial stem cells (SSCs), which are responsible for maintaining spermatogenesis throughout life in the male. Here we show the isolation of SSCs from adult mouse testis using genetic selection, with a success rate of 27%. These isolated SSCs respond to culture conditions and acquire embryonic stem cell properties. We name these cells multipotent adult germline stem cells (maGSCs). They are able to spontaneously differentiate into derivatives of the three embryonic germ layers in vitro and generate teratomas in immunodeficient mice. When injected into an early blastocyst, SSCs contribute to the development of various organs and show germline transmission. Thus, the capacity to form multipotent cells persists in adult mouse testis. Establishment of human maGSCs from testicular biopsies may allow individual cell-based therapy without the ethical and immunological problems associated with human embryonic stem cells. Furthermore, these cells may provide new opportunities to study genetic diseases in various cell lineages.

Human-induced pluripotent stem cells can be reprogrammed from all three somatic cell types, but with different efficiency. All analysed iPSCs can differentiate into cardiomyocytes, and the functionalities of cardiomyocytes derived from different cell origins are similar. However, MSC-derived hiPSCs revealed a higher cardiac differentiation efficiency than keratinocyte- and fibroblast-derived hiPSCs.

The successful isolation and cultivation of spermatogonial stem cells (SSCs) as well as induction of SSCs into pluripotent stem cells will allow us to study their biological characteristics and their applications in therapeutic approaches. Here we provide step-by-step procedures on the basis of previous work in our laboratory for: the isolation of testicular cells from adolescent mice by a modified enzymatic procedure; the enrichment of undifferentiated spermatogonia by laminin selection or genetic selection using Stra8-EGFP (enhanced green fluorescent protein) transgenic mice; the cultivation and conversion of undifferentiated spermatogonia into embryonic stem-like cells, so-called multipotent adult germline stem cells (maGSCs); and characterization of these cells. Normally, it will take about 16 weeks to obtain stable maGSC lines starting from the isolation of testicular cells.

In the absence of p110β function, spermatogenesis is dramatically disturbed because of a progressive reduction of differentiating spermatogones. Genetically modified mice and pharmacological inhibition of p110β confirmed this enzyme as the main PI3K isoform activated downstream of c-Kit.

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Purpose: We design a study to elucidate the precise molecular mechanisms by which Sorbitol-modified hyaluronic acid (sorbitol/HA) exerts beneficial effects in osteoarthritis (OA). Methods: Human OA chondrocytes were treated with increasing doses of sorbitol/HA and thereafter with or without interleukin-1beta (IL-1b) or hydrogen peroxide (H 2 O 2 ). Signal transduction pathways and parameters related to oxidative stress, apoptosis, inflammation, and catabolism were investigated.Results: Sorbitol/HA prevented IL-1 b-induced oxidative stress, as measured by reactive oxygen species (ROS), p47-NADPH oxidase (p47-NOX) phosphorylation, 4-hydroxynonenal (HNE) production and HNEmetabolizing glutathione-s-transferase A4-4 (Gsta4-4) expression. Moreover, sorbitol/HA stifled IL-1b-induced metalloproteinase 13 (MMP-13), nitric oxide (NO) and prostaglandin E2 (PGE 2 ) release as well as inducible NO synthase expression. Investigation of the apoptosis process revealed that this gel significantly attenuated cell death, caspase-3 activation and DNA fragmentation elicited by exposure to a cytotoxic H 2 O 2 dose. Examination of signalling pathway components revealed that sorbitol/HA prevented IL-1b-induced p38 mitogen-activated protein kinase and nuclear factor-kappa B activation, but not that of extracellular signal-regulated kinases 1 and 2. Conclusions: Altogether, our findings support a beneficial effect of sorbitol/HA in OA through restoring redox status and reducing markers of apoptosis, inflammation and catabolism involved in cartilage damage.

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