P53 and BCL-2 family proteins PUMA and NOXA define competitive fitness in pluripotent cell competition

Cell Competition is a process by which neighboring cells compare their fitness. As a result, viable but suboptimal cells are selectively eliminated in the presence of fitter cells. In the early mammalian embryo, epiblast pluripotent cells undergo extensive Cell Competition, which prevents suboptimal cells from contributing to the newly forming organism. While competitive ability is regulated by MYC in the epiblast, the mechanisms that contribute to competitive fitness in this context are largely unknown. Here, we report that P53 and its pro-apoptotic targets PUMA and NOXA regulate apoptosis susceptibility and competitive fitness in pluripotent cells. PUMA is widely expressed specifically in pluripotent cells in vitro and in vivo. We found that P53 regulates MYC levels in pluripotent cells, which connects these two Cell Competition pathways, however, MYC and PUMA/NOXA levels are independently regulated by P53. We propose a model that integrates a bifurcated P53 pathway regulating both MYC and PUMA/NOXA levels and determines competitive fitness.

[Remission of polycystic ovary syndrome associated with valproic acid in an epileptic female]

INTRODUCTION

In the epileptic female there is an increase in the number of disorders affecting the reproductive function, which on some occasions can be related to a polycystic ovary syndrome (PCOS). The Finnish school showed an increase in the number of cases of PCOS among females receiving antiepileptic therapy with valproic acid over a long period of time, which can affect up to 43% of the patients being treated. Such a high incidence has not been confirmed in other European series and it is likely that specific ethnic characteristics exert an influence on the results. We examine the possibility that PCOS constitutes a secondary chronic side effect of using valproic acid (VPA) and, as such, is reversible if the antiepileptic therapy is modified following its detection.

CASE REPORT

Female, aged 21, who developed PCOS during the course of therapy with VPA, which remitted after changing the treatment to lamotrigine. The clinical signs that have to act as a warning of the possible presence of PCOS in epileptic patients are the appearance of menstrual disorders or signs of virilisation, such as hirsutism and android obesity.