Mouse embryonic stem (ES) cells differentiate into cells of all three primary germ layers including endodermal cells that produce insulin in vitro . We show that constitutive expression of Pax4 (Pax4 ⁺ ), and to a lesser extent Pdx1 (Pdx1 ⁺ ), affects the differentiation of ES cells and significantly promote the development of insulin-producing cells. In Pax4 overexpressing R1 ES cells, isl-1, ngn3, insulin, islet amyloid polypeptide, and glucose transporter 2 (Glut-2) mRNA levels increase significantly. The number of nestin-expressing (nestin+) cells also increases. Constitutive Pax4 expression combined with selection of nestin+ cells and histotypic culture conditions give rise to spheroids containing insulin-positive granules typical of embryonal and adult β cells. In response to glucose, Pax4 ⁺ and wild-type ES-derived cells release insulin. Transplantation of these cells into streptozotocin-treated diabetic mice results in a normalization of blood glucose levels. We conclude that constitutive expression of Pax4 in combination with histotypic cultivation facilitates ES cell differentiation into the pancreatic lineage, which leads to the formation of islet-like spheroid structures that produce increased levels of insulin.

Heart disease is a leading cause of death with unmet clinical needs for targeted treatment options. Tumor necrosis factor alpha (TNF-α) represents a master pro-inflammatory cytokine that plays an important role in many immunopathogenic processes. Anti-TNF-α therapy is widely used in treating autoimmune inflammatory disorders, but in case of patients with heart disease, this treatment was unsuccessful or even harmful. The underlying reasons remain elusive until today. This review summarizes the effects of anti-TNF-α treatment in patients with and without heart disease and describes the involvement of TNF-α signaling in a number of animal models of cardiovascular diseases. We specifically focused on the role of TNF-α in specific cardiovascular conditions and in defined cardiac cell types. Although some mechanisms, mainly in disease development, are quite well known, a comprehensive understanding of TNF-α signaling in the failing heart is still incomplete. Published data identify pathogenic and cardioprotective mechanisms of TNF-α in the affected heart and highlight the differential role of two TNF-α receptors pointing to the complexity of the TNF-α signaling. In the light of these findings, it seems that targeting the TNF-α pathway in heart disease may show therapeutic benefits, but this approach must be more specific and selectively block pathogenic mechanisms. To this aim, more research is needed to better understand the molecular mechanisms of TNF-α signaling in the failing heart.