Differentiation of bone marrow stem cells into the cardiomyocyte-like cells induced by fetal cardiac supernatant with 6-bromoindirubin-3-oxime

Background Our previous study showed the 150 mg/mL fetal cardiac supernatant (FCS) could induce differentiation of BMSCs into cardiomyocye-like cells without cardiomyocyte touch,but differentiation efficiency is not high enough.Inhibition of glycogen synthase kinase-3 enhanced the proliferation and survives of stem cells.We tested if 6-bromoindirubin-3-oxime (BIO,glycogen synthase kinase-3 inhibitor) enhances the effects of FCS on differentiation of BMSCs and explore the growth factors in FCS.Methods BMSCs were isolated from the femur and tibia of four-week-old male Sprague-Dawley rats and co-cultured with FCS (150 mg/mL) that was made from fetal hearts from nineteen-day pregnant Wistar rats.BIO with different concentration (0,1,10,and 100 nM) was introduced in culture dishes.Transforming growth factor beta 1 (TGF-β1),bone morphogenetic protein 2 (BMP-2) and Akt in cardiac supernatant and culture medium were assayed with ELISA methods.Results After co-culturing with FCS,beating myotubes were observed in 25.9 % BMSCs dishes after 1 to 2 weeks’ culture.The levels of TGF-β1 and BMP-2 in FCS concentrations were no more than that in young and adult cardiac supernatant.All BIO groups significantly enhanced the effects of FCS on differentiation of BMSCs into the cardiomyocyte-like cells (1 nM,83 %;10 nM,73 %;100 nM,100 %).Akt levels were higher in BMSCs cultural medium with FCS.Conclusions FCS could induce the differentiation of BMSCs into the cardiomyocyte-like cells.TGF-β1 and BMP-2 might not play a role in the differentiation of BMSCs induced by FCS.BIO enhanced the effects of FCS on the differentiation of BMSCs into cardiomyocyte-like cells,which might involve the Akt pathway.     

A multivalent polyomavirus vaccine elicits durable neutralizing antibody responses in macaques

In 2019, there were about 100,000 kidney transplants globally, with more than a quarter of them performed in the United States. Unfortunately, some engrafted organs are lost to polyomavirus-associated nephropathy (PyVAN) caused by BK and JC viruses (BKPyV and JCPyV). Both viruses cause brain disease and possibly bladder cancer in immunosuppressed individuals. Transplant patients are routinely monitored for BKPyV viremia, which is an accepted hallmark of nascent nephropathy. If viremia is detected, a reduction in immunosuppressive therapy is standard care, but the intervention comes with increased risk of immune rejection of the engrafted organ. Recent reports have suggested that transplant recipients with high levels of polyomavirus-neutralizing antibodies are protected against PyVAN. Virus-like particle (VLP) vaccines, similar to approved human papillomavirus vaccines, have an excellent safety record and are known to induce high levels of neutralizing antibodies and long-lasting protection from infection. In this study, we demonstrate that VLPs representing BKPyV genotypes I, II, and IV, as well as JCPyV genotype 2 produced in insect cells elicit robust antibody titers. In rhesus macaques, all monkeys developed neutralizing antibody titers above a previously proposed protective threshold of 10,000. A second inoculation, administered 19 weeks after priming, boosted titers to a plateau of $\ge$ 25,000 that was maintained for almost two years. No vaccine-related adverse events were observed in any macaques. A multivalent BK/JC VLP immunogen did not show inferiority compared to the single-genotype VLP immunogens. Considering these encouraging results, we believe a clinical trial administering the multivalent VLP vaccine in patients waiting to receive a kidney transplant is warranted to evaluate its ability to reduce or eliminate PyVAN.