PDGF mediates derivation of human embryonic germ cells

Human Pluripotent Stem Cells in Reproductive Science-a Comparison of Protocols Used to Generate and Define Male Germ Cells from Pluripotent Stem Cells

Globally, fertility-related issues affect around 15% of couples. In 20%–30% of cases men are solely responsible, and they contribute in around 50% of all cases. Hence, understanding of in vivo germ-cell specification and exploring different angles of fertility preservation and infertility intervention are considered hot topics nowadays, with special focus on the use of human pluripotent stem cells (hPSCs) as a source of in vitro germ-cell generation. However, the generation of male germ cells from hPSCs can currently be considered challenging, making a judgment on the real perspective of these innovative approaches difficult. Ever since the first spontaneous germ-cell differentiation studies, using human embryonic stem cells, various strategies, including specific co-cultures, gene over-expression, and addition of growth factors, have been applied for human germ-cell derivation. In line with the variety of differentiation methods, the outcomes have ranged from early and migratory primordial germ cells up to post-meiotic spermatids. This variety of culture approaches and cell lines makes comparisons between protocols difficult. Considering the diverse strategies and outcomes, we aim in this mini-review to summarize the literature regarding in vitro derivation of human male germ cells from hPSCs, while keeping a particular focus on the culture methods, growth factors, and cell lines used.

Platelet-derived growth factor subunit B is required for tendon-bone healing using bone marrow-derived mesenchymal stem cells after rotator cuff repair in rats

As a common cause of shoulder pain and disability, rotator cuff injury (RCI) represents a debilitating condition affecting an individual's quality of life. Although surgical repair has been shown to be somewhat effective, many patients may still suffer from reduced shoulder function. The aim of the current study was to identify a more effective mode of RCI treatment by investigating the effect of platelet-derived growth factor subunit B (PDGF-B) on tendon-bone healing after RCI repair by modifying bone marrow-derived mesenchymal stem cells (BMSCs). Surface markers of BMSCs were initially detected by means of flow cytometry, followed by establishment of the rat models and construction of the lentiviral vector. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, Thiazolyl Blue Tetrazolium Bromide (MTT) assay, alizarin red staining, and oil red O staining were used to provide verification that PDGF-B was indeed capable of promoting BMSC viability, osteogenic and adipogenic differentiation capability. Furthermore, biomechanical assessment results indicated that PDGF-B could increase the ultimate load and stiffness of the tendon tissue. Real-time reverse-transcription quantitative polymerase chain reaction and Western blot analysis methods provided evidence suggesting that PDGF-B facilitated the expression of tendon-bone healing-related genes and proteins, while contrasting results were obtained after PDGF-B silencing. Taken together, the key findings of the current study provided evidence suggesting that overexpressed PDGF-B could act to enhance tendon-bone healing after RCI repair, thus highlighting the potential of the functional promotion of PDGF-B as a future RCI therapeutic approach.

PDGF in organ fibrosis

Fibrosis is part of a tissue repair response to injury, defined as increased deposition of extracellular matrix. In some instances, fibrosis is beneficial; however, in the majority of diseases fibrosis is detrimental. Virtually all chronic progressive diseases are associated with fibrosis, representing a huge number of patients worldwide. Fibrosis occurs in all organs and tissues, becomes irreversible with time and further drives loss of tissue function. Various cells types initiate and perpetuate pathological fibrosis by paracrine activation of the principal cellular executors of fibrosis, i.e. stromal mesenchymal cells like fibroblasts, pericytes and myofibroblasts. Multiple pathways are involved in fibrosis, platelet-derived growth factor (PDGF)-signaling being one of the central mediators. Stromal mesenchymal cells express both PDGF receptors (PDGFR) α and β, activation of which drives proliferation, migration and production of extracellular matrix, i.e. the principal processes of fibrosis. Here, we review the role of PDGF signaling in organ fibrosis, with particular focus on the more recently described ligands PDGF-C and -D. We discuss the potential challenges, opportunities and open questions in using PDGF as a potential target for anti-fibrotic therapies.

C9ORF135 encodes a membrane protein whose expression is related to pluripotency in human embryonic stem cells

Human embryonic stem cells (hESCs) are a unique population of cells defined by their capacity for self-renewal and pluripotency. Here, we identified a previously uncharacterized gene in hESCs, C9ORF135, which is sharply downregulated during gastrulation and gametogenesis, along with the pluripotency factors OCT4, SOX2, and NANOG. Human ESCs express two C9ORF135 isoforms, the longer of which encodes a membrane-associated protein, as determined by immunostaining and western blotting of fractionated cell lysates. Moreover, the results of chromatin immunoprecipitation (ChIP), mass spectrometry (MS), and co-immunoprecipitation (co-IP) analyses demonstrated that C9ORF135 expression is regulated by OCT4 and SOX2 and that C9ORF135 interacts with non-muscle myosin IIA and myosin IIB. Collectively, these data indicated that C9ORF135 encodes a membrane-associated protein that may serve as a surface marker for undifferentiated hESCs.

Cell Therapy in Patients with Critical Limb Ischemia

Critical limb ischemia (CLI) represents the most advanced stage of peripheral arterial obstructive disease (PAOD) with a severe obstruction of the arteries which markedly reduces blood flow to the extremities and has progressed to the point of severe rest pain and/or even tissue loss. Recent therapeutic strategies have focused on restoring this balance in favor of tissue survival using exogenous molecular and cellular agents to promote regeneration of the vasculature. These are based on stimulation of angiogenesis by extracellular and cellular components. This review article carries out a systematic analysis of the most recent scientific literature on the application of stem cells in patients with CLI. The results obtained from the detailed analysis of the recent literature data have confirmed the beneficial role of cell therapy in reducing the rate of major amputations in patients with CLI and improving their quality of life.