👤 Ellegård Rada

Hypertrophic cardiomyopathy (HCM), the most common inherited cardiomyopathy, is characterized by phenotypic and genetic heterogeneity. The present study describes the genotype data of a Swedish cohort of patients with HCM, the largest genetics study on Swedish HCM patients to date. The primary aims of this study were to unravel the main genetic findings and explore genotype-phenotype associations in this HCM cohort. Longitudinal data on 225 unrelated HCM index patients from the Southeast health care region in Sweden from 2010 until 2021 were assessed retrospectively. Patients were 46 ± 15.5 years-old, 67.6% males. In the cohort, 172/225 (76.4%) had genetic testing, of whom, 65/172 (38%) were considered genotype positive (G +) for a pathogenic/ likely pathogenic variant, mainly in the two most common sarcomeric genes: MYBPC3 (57%) and MYH7 (34%). In 43% (74/172) of patients, no reportable variants were detected, classified as genotype negative (G-). In the remaining 33 patients (19%), variants of uncertain significance (VUS) were identified; this group was not included in the comparative analyses. Genotype positive patients (G +) were characterized by younger age (p = 0.010), higher prevalence of family history of HCM (p < 0.001), greater maximum left ventricle wall thickness (p = 0.03) and an increased incidence of sudden cardiac death (SCD) (p = 0.045). At first clinical screening, HCM was diagnosed in 28/65(43%) in the G + families and in 2/74 (2.7%) G-families (p < 0.001). Genotype-positive HCM patients differ with respect to age at presentation, family history of the disease, morphology, incidence of SCD and presence of HCM in their family members at first clinical assessment from genotype-negative patients. Genotype negative status in this HCM cohort, though, did not confer immunity from adverse complications. Show less

Nuclear factor (erythroid-derived 2)-like 2 (NRF2) is a master regulator of oxidant and xenobiotic metabolism, but it is unknown how it is regulated to provide basal expression of this defense system. Here, we studied the putative connection between NRF2 and the canonical WNT pathway, which modulates hepatocyte metabolism. WNT-3A increased the levels of NRF2 and its transcriptional signature in mouse hepatocytes and HEK293T cells. The use of short interfering RNAs in hepatocytes and mouse embryonic fibroblasts which are deficient in the redox sensor Kelch-like ECH-associated protein 1 (KEAP1) indicated that WNT-3A activates NRF2 in a β-Catenin- and KEAP1-independent manner. WNT-3A stabilized NRF2 by preventing its GSK-3-dependent phosphorylation and subsequent SCF/β-TrCP-dependent ubiquitination and proteasomal degradation. Axin1 and NRF2 were physically associated in a protein complex that was regulated by WNT-3A, involving the central region of Axin1 and the Neh4/Neh5 domains of NRF2. Axin1 knockdown increased NRF2 protein levels, while Axin1 stabilization with Tankyrase inhibitors blocked WNT/NRF2 signaling. The relevance of this novel pathway was assessed in mice with a conditional deletion of Axin1 in the liver, which showed upregulation of the NRF2 signature in hepatocytes and disruption of liver zonation of antioxidant metabolism. NRF2 takes part in a protein complex with Axin1 that is regulated by the canonical WNT pathway. This new WNT-NRF2 axis controls the antioxidant metabolism of hepatocytes. These results uncover the participation of NRF2 in a WNT-regulated signalosome that participates in basal maintenance of hepatic antioxidant metabolism. Show less