DEPTOR promoter genetic variants and insulin resistance in obese children and adolescents.

BACKGROUND: Insulin resistance (IR) is one of the major metabolic complications of obesity in children and adolescents. DEP domain-containing mammalian target of rapamycin interacting protein (DEPTOR) is involved in downstream insulin signaling and DEPTOR's effects are regulated by its level of expression. OBJECTIVES: To analyze promoter region of DEPTOR for genetic variants associated with altered IR in obese children and adolescents. SUBJECTS AND METHODS: IR was determined in 322 normoglycemic obese subjects [173 females, 149 males; mean age 13.3 ± 3.5 yr, mean BMI-SDS 2.85 ± 0.83, HbA1C 5.2 ± 0.2% (33 ± 2.5 mmol/mol)] using homeostatic model assessment - insulin resistance [HOMA-IR (>2 prepubertal and >3 pubertal)] and whole body insulin sensitivity index [WBISI (<6.5 prepubertal and <4.5 pubertal)]. Genetic variants, determined by high resolution melting analysis, were confirmed by Sanger sequencing, whereas population allele distribution was determined by TaqMan genotyping probes. RESULTS: Genetic variant c.-143T>C (rs7840156) was associated with a significant 2-fold decreased risk to present with IR, determined by HOMA-IR [odds ratio (OR) = 0.614, 95% confidence interval (CI) = 0.435-0.867, p = 0.0057) and WBISI (OR = 0.582, 95% CI = 0.414-0.817, p = 0.0018). The CC genotype had lower mean HOMA-IR value (2.47 ± 0.44 vs. 3.04 ± 0.14, p = 0.0177) and higher mean WBISI value (7.00 ± 0.71 vs. 5.27 ± 0.33, p = 0.0235) than TT genotype. Variant c.-143T>C was located in evolutionary highly conserved region in DEPTOR promoter region. CONCLUSION: Presented results on association between insulin sensitivity and genetic variants in DEPTOR gene suggest DEPTOR and mammalian target of rapamycin signaling pathway to be potential target for future research and pharmacological interventions.

The p-rpS6-zone delineates wounding responses and the healing process.

The spatial boundaries of tissue response to wounding are unknown. Here, we show that in mammals, the ribosomal protein S6 (rpS6) is phosphorylated in response to skin injury, forming a zone of activation surrounding the region of the initial insult. This p-rpS6-zone forms within minutes after wounding and is present until healing is complete. The zone is a robust marker of healing as it encapsulates features of the healing process, including proliferation, growth, cellular senescence, and angiogenesis. A mouse model that is unable to phosphorylate rpS6 shows an initial acceleration of wound closure, but results in impaired healing, identifying p-rpS6 as a modulator but not a driver of healing. Finally, the p-rpS6-zone accurately reports on the status of dermal vasculature and the effectiveness of healing, visually dividing an otherwise homogeneous tissue into regions with distinct properties.

PIK3AP1 and SPON2 Genes Are Differentially Methylated in Patients With Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Adenitis (PFAPA) Syndrome.

Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome is the most common autoinflammatory disease in children and is often grouped together with hereditary periodic fever syndromes, although its cause and hereditary nature remain unexplained. We investigated whether differential DNA methylation was present in DNA from peripheral blood mononuclear cells (PBMC) in patients with PFAPA vs. healthy controls. A whole-epigenome analysis (MeDIP and MBD) was performed using pooled DNA libraries enriched for methylated genomic regions and identified candidate genes, two of which were further evaluated with methylation-specific restriction enzymes coupled with qPCR (MSRE-qPCR). The analysis showed that the PIK3AP1 and SPON2 gene regions are differentially methylated in patients with PFAPA. MSRE-qPCR proved to be a quick, reliable, and cost-effective method of confirming results from MeDIP and MBD. Our findings indicate that a B-cell adapter protein (PIK3AP1), as the PI3K binding inhibitor of inflammation, and spondin-2 (SPON2), as a pattern recognition molecule and integrin ligand, could play a role in the etiology of PFAPA. Their role and the impact of changed DNA methylation in PFAPA etiology and autoinflammation need further investigation.

Elevated Homocysteine after Elevated Propionylcarnitine or Low Methionine in Newborn Screening Is Highly Predictive for Low Vitamin B12 and Holo-Transcobalamin Levels in Newborns.

Early diagnostics and treatment of vitamin B12 deficiency (B12D) in infants, mainly maternally conditioned, is crucial in preventing possible developmental delay and neurological deficits. Currently, B12D is rarely listed in regular newborn screening panels and mostly regarded as an incidental finding. The aim of this study was to evaluate a targeted newborn screening strategy for detection of suspected B12D. A decision strategy based on the primary parameters propionylcarnitine and methionine for selection of samples to be analyzed for total homocysteine by mass spectrometry was established. Therefore, 93,116 newborns were initially screened. Concentrations of vitamin B12 and holotranscobalamin in serum were obtained from clinical follow-up analyses of recalled newborns. Moreover, an extremely sensitive mass spectrometric method to quantify methylmalonic acid from the dried blood spots was developed. Overall, 0.15% of newborns were screened positive for suspected B12D, of which 64% had vitamin B12 concentrations below 148 pM. We also determined a cutoff value for methylmalonic acid in dried blood spots indicative for B12D in infants. Overall, we calculated a prevalence of 92/100,000 for suspected B12D in the Austrian newborns. In conclusion, we present a screening algorithm including second-tier measurement of total homocysteine that allows detection of low B12 serum concentrations with a high detection rate and low false-positive rate.