Differentiation of mouse embryonic stem cells into cells with spermatogonia-like morphology with chemical intervention-dependent increased gene expression of LIM homeobox 1 (Lhx1).

Spermatogonial stem cells (SSCs) originate from gonocytes that differentiate from primordial germ cells (PGCs). In the developing mouse testis, expression of the gene LIM homeobox 1 (Lhx1) marks the most undifferentiated SSCs, which has not yet been reported for spermatogonia-like cells generated in vitro. Previously, it was shown that a chemical intervention in male mouse embryonic stem (ES) cells in serum culture, including Sirtuin 1 (SIRT1) inhibitor Ex-527, DNA methyltransferase (DNMT) inhibitor RG-108 and electrophilic redox cycling compound tert-butylhydroquinone (tBHQ), was associated with molecular markers of PGC to gonocyte differentiation.

Clot-entrapped blood cells in synergy with human mesenchymal stem cells create a pro-angiogenic healing response.

Blood clots stop bleeding and provide cell-instructive microenvironments. Still, in vitro models used to study implant performance typically neglect any possible interactions of recruited cells with surface-adhering blood clots. Here we study the interaction and synergies of bone marrow derived human mesenchymal stem cells (hMSCs) with surface-induced blood clots in an in vitro model by fluorescence microscopy, scanning and correlative light and electron microscopy, ELISA assays and zymography.

A gonogenic stimulated transition of mouse embryonic stem cells with enhanced control of diverse differentiation pathways.

Embryonic stem (ES) cells share markers with undifferentiated primordial germ cells (PGCs). Here, we discovered that a cellular state with some molecular markers of male gonocyte induction, including a G1/S phase arrest and upregulation of specific genes such as Nanos2, Tdrd1, Ddx4, Zbtb16 and Plk1s1, can be chemically induced in male mouse ES cells in vitro, which we termed gonogenic stimulated transition (GoST). After longer culture of the resulting GoST cells without chemical stimulation, several molecular markers typical for early gonocytes were detected including the early gonocyte marker Tex101.

Mesenchymal stem cells exploit extracellular matrix as mechanotransducer.

While stem cells can sense and respond to physical properties of their environment, the molecular aspects how physical information is translated into biochemical signals remain unknown. Here we show that human mesenchymal stem cells (hMSCs) harvest and assemble plasma fibronectin into their extracellular matrix (ECM) fibrils within 24 hours. hMSCs pro-actively pull on newly assembled fibronectin ECM fibrils, and the fibers are more stretched on rigid than on soft fibronectin-coated polyacrylamide gels.

Investigation of dmyc Promoter and Regulatory Regions.

Products of the myc gene family integrate extracellular signals by modulating a wide range of their targets involved in cellular biogenesis and metabolism; the purpose of this integration is to regulate cell death, proliferation, and differentiation. However, understanding the regulation of myc at the transcription level remains a challenge. We performed rapid amplification of dmyc cDNA ends (5' RACE) and mapped the transcription start site at P1 promoter, 18 base pairs upstream of the start of the known EST GM01143 and within the 5' UTR.

Identification of cis-Regulatory Elements in the dmyc Gene of Drosophila Melanogaster.

Myc is a crucial regulator of growth and proliferation during animal development. Many signals and transcription factors lead to changes in the expression levels of Drosophila myc, yet no clear model exists to explain the complexity of its regulation at the level of transcription. In this study we used Drosophila genetic tools to track the dmyc cis-regulatory elements.