Screening of 23 candidate genes by next-generation sequencing of patients with permanent congenital hypothyroidism: novel variants in TG, TSHR, DUOX2, FOXE1, and SLC26A7.

PURPOSE: To date, many genes have been associated with congenital hypothyroidism (CH). Our aim was to identify the mutational spectrum of 23 causative genes in Turkish patients with permanent CH, including thyroid dysgenesis (TD) and dyshormonogenesis (TDH) cases. METHODS: A total of 134 patients with permanent CH (130 primary, 4 central) were included. To identify the genetic etiology, we screened 23 candidate genes associated with CH by next-generation sequencing. For confirmation and to detect the status of the specific familial variant in relatives, Sanger sequencing was also performed. RESULTS: Possible pathogenic variants were found in 5.2% of patients with TD and in 64.0% of the patients with normal-sized thyroid or goiter. In all patients, variants were most frequently found in TSHR, followed by TPO and TG. The same homozygous TSHB variant (c.162 + 5G > A) was identified in four patients with central CH. In addition, we detected novel variants in the TSHR, TG, SLC26A7, FOXE1, and DUOX2. CONCLUSION: Genetic causes were determined in the majority of CH patients with TDH, however, despite advances in genetics, we were unable to identify the genetic etiology of most CH patients with TD, suggesting the effect of unknown genes or environmental factors. The previous studies and our findings suggest that TSHR and TPO mutations is the main genetic defect of CH in the Turkish population.

The role of vitamin C in the gene expression of oxidative stress markers in fibroblasts from burn patients.

PURPOSE: To assess the action of vitamin C on the expression of 84 oxidative stress related-genes in cultured skin fibroblasts from burn patients. METHODS: Skin samples were obtained from ten burn patients. Human primary fibroblasts were isolated and cultured to be distributed into 2 groups: TF (n = 10, fibroblasts treated with vitamin C) and UF (n = 10, untreated fibroblasts). Gene expression analysis using quantitative polymerase chain reaction array was performed for comparisons between groups. RESULTS: The comparison revealed 10 upregulated genes as follows: arachidonate 12-lipoxygenase (ALOX12), 24-dehydrocholesterol reductase (DHCR24), dual oxidase 1 (DUOX1), glutathione peroxidase 2 (GPX2), glutathione peroxidase 5 (GPX5), microsomal glutathione S-transferase 3 (MGST3), peroxiredoxin 4 (PRDX4), phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 1 (P-REX1), prostaglandin-endoperoxide synthase 1 (PTGS1), and ring finger protein 7 (RNF7). CONCLUSION: Cultured fibroblasts obtained from burn patients and treated with vitamin C resulted in 10 differentially expressed genes, all overexpressed, with DUOX1, GPX5, GPX2 and PTGS1 being of most interest.

The role of vitamin C in the gene expression of oxidative stress markers in fibroblasts from burn patients

Abstract Purpose: To assess the action of vitamin C on the expression of 84 oxidative stress related-genes in cultured skin fibroblasts from burn patients. Methods: Skin samples were obtained from ten burn patients. Human primary fibroblasts were isolated and cultured to be distributed into 2 groups: TF (n = 10, fibroblasts treated with vitamin C) and UF (n = 10, untreated fibroblasts). Gene expression analysis using quantitative polymerase chain reaction array was performed for comparisons between groups. Results: The comparison revealed 10 upregulated genes as follows: arachidonate 12-lipoxygenase (ALOX12), 24-dehydrocholesterol reductase (DHCR24), dual oxidase 1 (DUOX1), glutathione peroxidase 2 (GPX2), glutathione peroxidase 5 (GPX5), microsomal glutathione S-transferase 3 (MGST3), peroxiredoxin 4 (PRDX4), phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 1 (P-REX1), prostaglandin-endoperoxide synthase 1 (PTGS1), and ring finger protein 7 (RNF7). Conclusion: Cultured fibroblasts obtained from burn patients and treated with vitamin C resulted in 10 differentially expressed genes, all overexpressed, with DUOX1, GPX5, GPX2 and PTGS1 being of most interest.

Autophagy regulates DUOX1 localization and superoxide production in airway epithelial cells during chronic IL-13 stimulation.

The airway epithelium is a broad interface with the environment, mandating well-orchestrated responses to properly modulate inflammation. Classically, autophagy is a homeostatic pathway triggered in response to external cellular stresses, and is elevated in chronic airway diseases. Recent findings highlight the additional role of autophagy in vesicle trafficking and protein secretion, implicating autophagy pathways in complex cellular responses in disease. Th2 cytokines, IL-13 and IL-4, are increased in asthma and other airway diseases contributing to chronic inflammation. Previously, we observed that IL-13 increases reactive oxygen species (ROS) in airway epithelial cells in an autophagy-dependent fashion. Here, we tested our hypothesis that autophagy is required for IL-13-mediated superoxide production via the NADPH oxidase DUOX1. Using a mouse model of Th2-mediated inflammation induced by OVA-allergen, we observed elevated lung amounts of IL-13 and IL-4 accompanied by increased autophagosome levels, determined by LC3BII protein levels and immunostaining. ROS levels were elevated and DUOX1 expression was increased 70-fold in OVA-challenged lungs. To address the role of autophagy and ROS in the airway epithelium, we treated primary human tracheobronchial epithelial cells with IL-13 or IL-4. Prolonged, 7-day treatment increased autophagosome formation and degradation, while brief activation had no effect. Under parallel culture conditions, IL-13 and IL-4 increased intracellular superoxide levels as determined by electron paramagnetic resonance (EPR) spectroscopy. Prolonged IL-13 activation increased DUOX1, localized at the apical membrane. Silencing DUOX1 by siRNA attenuated IL-13-mediated increases in superoxide, but did not reduce autophagy activities. Notably, depletion of autophagy regulatory protein ATG5 significantly reduced superoxide without diminishing total DUOX1 levels. Depletion of ATG5, however, diminished DUOX1 localization at the apical membrane. The findings suggest non-canonical autophagy activity regulates DUOX1-dependent localization required for intracellular superoxide production during Th2 inflammation. Thus, in chronic Th2 inflammatory airway disease, autophagy proteins may be responsible for persistent intracellular superoxide production.