RESUMO
To reveal how cells exit human pluripotency, we designed a CRISPR-Cas9 screen exploiting the metabolic and epigenetic differences between naïve and primed pluripotent cells. We identify the tumor suppressor, Folliculin(FLCN) as a critical gene required for the exit from human pluripotency. Here we show that FLCN Knock-out (KO) hESCs maintain the naïve pluripotent state but cannot exit the state since the critical transcription factor TFE3 remains active in the nucleus. TFE3 targets up-regulated in FLCN KO exit assay are members of Wnt pathway and ESRRB. Treatment of FLCN KO hESC with a Wnt inhibitor, but not ESRRB/FLCN double mutant, rescues the cells, allowing the exit from the naïve state. Using co-immunoprecipitation and mass spectrometry analysis we identify unique FLCN binding partners. The interactions of FLCN with components of the mTOR pathway (mTORC1 and mTORC2) reveal a mechanism of FLCN function during exit from naïve pluripotency.
Assuntos
Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Via de Sinalização Wnt/fisiologia , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Sistemas CRISPR-Cas/genética , Sistemas CRISPR-Cas/fisiologia , Linhagem Celular , Estrona/genética , Estrona/metabolismo , Humanos , Imunoprecipitação , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 2 de Rapamicina/genética , Proteômica , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Via de Sinalização Wnt/genéticaRESUMO
INTRODUCTION: Pro12Ala polymorphism is a missense mutation at codon 12 in peroxisome proliferator-activated receptor γ gene (PPARG). This polymorphism is known to be associated with increased insulin sensitivity. Pioglitazone, a thiazolidinedione, is an anti-diabetic drug which acts as an agonist at PPAR γ receptor. AIM: To determine the association between Pro12Ala polymorphism of the PPARG and variation in therapeutic response to the PPARγ agonist, pioglitazone. MATERIALS AND METHODS: The study was done as a hospital based pilot project in 30 patients with type 2 diabetes mellitus, on treatment with sulfonylurea or metformin but without adequate glycaemic control. They were started on pioglitazone as add on therapy for a period of 12 weeks. The participants were categorized as responders and non-responders based on the change in HbA1C level after 12 weeks. Pro12Ala polymorphism was analysed by polymerase chain reaction-restriction fragment length polymorphism. STATISTICAL ANALYSIS: Logistic regression analysis was done to evaluate the associations between age, baseline body weight, BMI, waist circumference, waist-hip ratio and Pro12Ala variants with the response to pioglitazone. The p-value< 0.05 was considered significant. RESULTS: The frequency distributions of PPAR gamma genotypes were 80% for Pro/Pro and 20% for Pro/Ala in the study population. Among the study participants, 30% were non-responders and 70% responders to pioglitazone. A significantly higher frequency of the polymorphism was detected in the responders (p=0.005) compared to non-responders group. CONCLUSION: Our study suggests that there is a potential association between Pro12Ala polymorphism and glycaemic response to pioglitazone.
RESUMO
We report the case of a patient with recurrent impetigo herpetiformis associated with diabetes mellitus, hypoalbuminemia, and hypocalcaemia; who was refractory to corticosteroids. Cyclosporine along with other supportive measures proved to be life-saving with maintenance of pregnancy.
RESUMO
A female patient with short stature, of systemic lupus erythematosis and hypocalcemia presented to us. On examination and investigations she was found to be a case of Type Ia pseudohypoparathyroidism. The patient's quality of life improved after appropriate treatment. The case is a rare combination of two disorders.