A rare case of extraovarian dysgerminoma in pregnancy

Extraovarian germ cell tumors are very rare and their occurrence in pregnancy is extremely rare. We presented a case of extraovarian dysgerminoma on the anterior abdominal wall in a G2P1L1, 34 weeks. It is challenging to manage such tumors, obstacles in the way namely are diagnosis as the presentation can be different from classical ovarian GCTs, limitations in the investigatory modalities in pregnancy, and management involving three independent entities-tumor, mother, fetus.

Piezo1 channel activation mimics high glucose as a stimulator of insulin release

Glucose and hypotonicity induced cell swelling stimulate insulin release from pancreatic β-cells but the mechanisms are poorly understood. Recently, Piezo1 was identified as a mechanically-activated nonselective Ca2+ permeable cationic channel in a range of mammalian cells. As cell swelling induced insulin release could be through stimulation of Ca2+ permeable stretch activated channels, we hypothesised a role for Piezo1 in cell swelling induced insulin release. Two rat β-cell lines (INS-1 and BRIN-BD11) and freshly-isolated mouse pancreatic islets were studied. Intracellular Ca2+ measurements were performed using the fura-2 Ca2+ indicator dye and ionic current was recorded by whole cell patch-clamp. Piezo1 agonist Yoda1, a competitive antagonist of Yoda1 (Dooku1) and an inactive analogue of Yoda1 (2e) were used as chemical probes. Piezo1 mRNA and insulin secretion were measured by RT-PCR and ELISA respectively. Piezo1 mRNA was detected in both β-cell lines and mouse islets. Yoda1 evoked Ca2+ entry was inhibited by Yoda1 antagonist Dooku1 as well as other Piezo1 inhibitors gadolinium and ruthenium red, and not mimicked by 2e. Yoda1, but not 2e, stimulated Dooku1-sensitive insulin release from β-cells and pancreatic islets. Hypotonicity and high glucose increased intracellular Ca2+ and enhanced Yoda1 Ca2+ influx responses. Yoda1 and hypotonicity induced insulin release were significantly inhibited by Piezo1 specific siRNA. Pancreatic islets from mice with haploinsufficiency of Piezo1 released less insulin upon exposure to Yoda1. The data show that Piezo1 channel agonist induces insulin release from β-cell lines and mouse pancreatic islets suggesting a role for Piezo1 in cell swelling induced insulin release. Hence Piezo1 agonists have the potential to be used as enhancers of insulin release

Force Sensing by Piezo Channels in Cardiovascular Health and Disease

Mechanical forces are fundamental in cardiovascular biology, and deciphering the mechanisms by which they act remains a testing frontier in cardiovascular research. Here, we raise awareness of 2 recently discovered proteins, Piezo1 and Piezo2, which assemble as transmembrane triskelions to combine exquisite force sensing with regulated calcium influx. There is emerging evidence for their importance in endothelial shear stress sensing and secretion, NO generation, vascular tone, angiogenesis, atherosclerosis, vascular permeability and remodeling, blood pressure regulation, insulin sensitivity, exercise performance, and baroreceptor reflex, and there are early suggestions of relevance to cardiac fibroblasts and myocytes. Human genetic analysis points to significance in lymphatic disease, anemia, varicose veins, and potentially heart failure, hypertension, aneurysms, and stroke. These channels appear to be versatile force sensors, used creatively to inform various force-sensing situations. We discuss emergent concepts and controversies and suggest that the potential for new important understanding is substantial

Genetic variants of PIEZO1 associate with COVID-19 fatality

Fatality from coronavirus disease 19 (COVID-19) is a major problem globally and so identification of its underlying molecular mechanisms would be helpful. The combination of COVID-19 clinical data and genome sequence information is providing a potential route to such mechanisms. Here we took a candidate gene approach to UK Biobank data based on the suggested roles of endothelium and membrane proteins in COVID-19. We focussed on the PIEZO1 gene, which encodes a non-selective cation channel that mediates endothelial responses to blood flow. The analysis suggests 3 missense PIEZO1 single nucleotide polymorphisms (SNPs) associated with COVID-19 fatality independently of risk factors. All of them affect amino acids in the proximal N-terminus of PIEZO1, which is an unexplored region of the protein. By using molecular modelling we predict location of all 3 amino acids to a common outward-facing structure of unknown functional significance at the tips of the PIEZO1 propeller blades. Through genome sequence analysis we show that these SNPs vary in prevalence with ethnicity and that the most significant SNP (rs7184427) varies between 65 to 90% even though the reference amino acid is evolutionarily conserved. The data suggest PIEZO1 as a contributor to COVID-19 fatality and factor in ethnic susceptibility