Antiapoptotic Protein FAIM2 is targeted by miR-3202, and DUX4 via TRIM21, leading to cell death and defective myogenesis.

Inappropriate expression of DUX4, a transcription factor that induces cell death at high levels of expression and impairs myoblast differentiation at low levels of expression, leads to the development of facioscapulohumeral muscular dystrophy (FSHD), however, the pathological mechanisms downstream of DUX4 responsible for muscle loss are poorly defined. We performed a screen of 1972 miR inhibitors for their ability to interfere with DUX4-induced cell death of human immortalized myoblasts. The most potent hit identified by the screen, miR-3202, is known to target the antiapoptotic protein FAIM2. Inhibition of miR-3202 led to the upregulation of FAIM2, and remarkably, expression of DUX4 led to reduced cellular levels of FAIM2. We show that the E3 ubiquitin ligase and DUX4 target gene, TRIM21, is responsible for FAIM2 degradation downstream of DUX4. Human myoblasts overexpressing FAIM2 showed increased resistance to DUX4-induced cell death, whereas in wild-type cells FAIM2 knockdown resulted in increased apoptosis and failure to differentiate into myotubes. The necessity of FAIM2 for myogenic differentiation of WT cells led us to test the effect of FAIM2 overexpression on the impairment of myogenesis by DUX4. Strikingly, FAIM2 overexpression rescued the myogenic differentiation defect caused by low-level expression of DUX4. These data implicate FAIM2 levels, modulated by DUX4 through TRIM21, as an important factor mediating the pathogenicity of DUX4, both in terms of cell viability and myogenic differentiation, and thereby open a new avenue of investigation towards drug targets in FSHD.

Correlation of levetiracetam concentration in peripheral blood mononuclear cells with clinical efficacy: A sensitive monitoring biomarker in patients with epilepsy.

PURPOSE: Therapeutic drug monitoring (TDM) is increasingly recommended in antiepileptic drug (AED) therapy, yet a complex relationship exists between the unbound-drug serum concentration (Cu.serum) as a monitoring biomarker and clinical efficacy. The study was designed to investigate the validity of the intracellular unbound-drug concentration in Peripheral Blood Mononuclear Cells (Cu.PBMC) as a feasible TDM tool in relation to levetiracetam (LEV). METHODS: Patients from epilepsy out-patient centre were included in a 4-month descriptive prospective study. Trough serum and PBMC LEV concentrations were monthly determined using HPLC and correlated with clinical features, demographic data, and P-glycoprotein (P-gp) expression. RESULTS: Seventy-patients completed the study with a LEV dose range of 500-3000 mg/day. An absolute range for LEV Cu.serum and Cu.PBMC was 1.00-26.99 and 0.33-4.43 µg/mL, respectively. Unlike Cu.serum, the average four-month LEV Cu.PBMC displayed a significant positive correlation with clinical features and P-gp expression; where patients with higher LEV Cu.PBMC experienced less number of seizure/month, better cognition and quality of life, and had a more reduction in P-gp expression, but no significant correlation with LEV daily dose was observed. A therapeutic response threshold of ≥ 0.82 µg/mL for LEV Cu.PBMCwas perceived by using a receiver operating characteristic curve that related the number of seizure/month to the LEV Cu.PBMC. The validity of this therapeutic threshold was significant in contrast to LEV Cu.serum. CONCLUSION: Levetiracetam PBMC concentration is a more sensitive biomarker for LEV efficacy and correlates better with clinical events than Cu.serum and could represent a novel tool for more precise LEV monitoring.

Suppression of connective tissue growth factor mediates the renoprotective effect of Sitagliptin rather than Pioglitazone in type 2 diabetes mellitus.

AIM: Diabetic nephropathy (DN) is a leading cause of end-stage renal disease, and thus, the ability of antidiabetic drugs to ameliorate renal microvascular disease may be as important as their ability to control blood glucose. Therefore, we investigated the reno-protective effect of the antidiabetic drugs, Sitagliptin and Pioglitazone, versus combined Metformin/Enalapril in a rat model of type 2 diabetes. METHOD: Male Wistar rats were randomly assigned to be either normal control or diabetic. Induction of type 2 diabetes was done by intraperitoneal injection of\ low dose streptozotocin (35mg/kg) on top of 2 weeks of high fat diet. Hyperglycemic animals were divided into 4 groups: untreated diabetic, Sitagliptin (10mg/kg), Pioglitazone (10mg/kg) and Metformin/Enalapril (500, 10mg/kg, respectively) treated. After 6 weeks, fasting blood glucose, plasma insulin, ß-cell function, insulin resistance, serum lipids, urea & creatinine, albuminurea, kidney weight, renal oxidative stress, plasma connective tissue growth factor (CTGF) and renal histopathology were assessed. KEY FINDINGS: Sitagliptin decreased microalbuminurea, urea & creatinine, renal tropism, oxidative stress and CTGF to levels similar to Metformin/Enalapril group. It also preserved near normal renal histology. Although Pioglitazone treatment reduced urea, creatinine, renal tropism and oxidative stress, it did not improve renal pathological changes or significantly alter CTCF. SIGNIFICANCE: Early Sitagliptin treatment in type 2 diabetes can equally ameliorate renal functions and structural changes as combined Metformin/Enalapril. Moreover Sitagliptin is a better renoprotective than Pioglitazone, probably due to its suppressor effect on CTGF, a key factor mediating diabetic renal injury.