Novel Pan-ERR Agonists Ameliorate Heart Failure Through Enhancing Cardiac Fatty Acid Metabolism and Mitochondrial Function.

BACKGROUND: Cardiac metabolic dysfunction is a hallmark of heart failure (HF). Estrogen-related receptors ERRα and ERRγ are essential regulators of cardiac metabolism. Therefore, activation of ERR could be a potential therapeutic intervention for HF. However, in vivo studies demonstrating the potential usefulness of ERR agonist for HF treatment are lacking, because compounds with pharmacokinetics appropriate for in vivo use have not been available. METHODS: Using a structure-based design approach, we designed and synthesized 2 structurally distinct pan-ERR agonists, SLU-PP-332 and SLU-PP-915. We investigated the effect of ERR agonist on cardiac function in a pressure overload-induced HF model in vivo. We conducted comprehensive functional, multi-omics (RNA sequencing and metabolomics studies), and genetic dependency studies both in vivo and in vitro to dissect the molecular mechanism, ERR isoform dependency, and target specificity. RESULTS: Both SLU-PP-332 and SLU-PP-915 significantly improved ejection fraction, ameliorated fibrosis, and increased survival associated with pressure overload-induced HF without affecting cardiac hypertrophy. A broad spectrum of metabolic genes was transcriptionally activated by ERR agonists, particularly genes involved in fatty acid metabolism and mitochondrial function. Metabolomics analysis showed substantial normalization of metabolic profiles in fatty acid/lipid and tricarboxylic acid/oxidative phosphorylation metabolites in the mouse heart with 6-week pressure overload. ERR agonists increase mitochondria oxidative capacity and fatty acid use in vitro and in vivo. Using both in vitro and in vivo genetic dependency experiments, we show that ERRγ is the main mediator of ERR agonism-induced transcriptional regulation and cardioprotection and definitively demonstrated target specificity. ERR agonism also led to downregulation of cell cycle and development pathways, which was partially mediated by E2F1 in cardiomyocytes. CONCLUSIONS: ERR agonists maintain oxidative metabolism, which confers cardiac protection against pressure overload-induced HF in vivo. Our results provide direct pharmacologic evidence supporting the further development of ERR agonists as novel HF therapeutics.

Assigning pathogenicity for TAB2 variants using a novel scalable functional assay and expanding TAB2 disease spectrum.

Haploinsufficiency of TGF-beta-activated kinase 1 (MAP3K7) binding protein 2 (TAB2) has been associated with congenital heart disease and more recently multiorgan structural abnormalities. Missense variant represents a major proportion of non-synonymous TAB2 variants reported in gnomAD (295/576) and Clinvar (16/73), most of which are variants of uncertain significance (VUSs). However, interpretation of TAB2 missense variants remains challenging because of lack of functional assays. To address this issue, we established a cell-based luciferase assay that enables high-throughput screening of TAB2 variants to assess the functional consequence for predicting variant pathogenicity. Using this platform, we screened 47 TAB2 variants including five pathogenic controls and one benign control, and the results showed that the transcriptional activity of activator protein 1 (AP-1) but not nuclear factor kappa B predicts the TAB2 variant pathogenicity. This assay provides accurate functional readout for both loss-of-function (LOF) and gain-of-function variants, which are associated with distinct phenotypes. In all, 22 out of 32 tested VUSs were reclassified. Genotype-Phenotype association showed that most patients with partial LOF variants do not exhibit congenital heart disease but high frequency of developmental delay, hypotonia and dysmorphic features, which suggests that genetic testing for TAB2 is needed for a broader spectrum of patients with more diverse phenotypes. Molecular modeling with Npl4 zinc finger (NZF) domain variants revealed that the stability of the NZF domain in TAB2 protein is crucial for AP-1 activation. In conclusion, we developed a highly effective functional assay for TAB2 variant prediction and interpretation.

SR9009 improves heart function after pressure overload independent of cardiac REV-ERB.

The core clock component REV-ERB is essential for heart function. Previous studies show that REV-ERB agonist SR9009 ameliorates heart remodeling in the pressure overload model with transverse aortic constriction (TAC). However, it is unknown whether SR9009 indeed works through cardiac REV-ERB, given that SR9009 might target other proteins and that REV-ERB in non-cardiac tissues might regulate cardiac functions indirectly. To address this question, we generated the REV-ERBα/ß cardiac-specific double knockout mice (cDKO). We found that REV-ERB cardiac deficiency leads to profound dilated cardiac myopathy after TAC compared to wild-type (WT) control mice, confirming the critical role of REV-ERB in protecting against pressure overload. Interestingly, the cardioprotective effect of SR9009 against TAC retains in cDKO mice. In addition, SR9009 administered at the time points corresponding to the peak or trough of REV-ERB expression showed similar cardioprotective effects, suggesting the REV-ERB-independent mechanisms in SR9009-mediated post-TAC cardioprotection. These findings highlight that genetic deletion of REV-ERB in cardiomyocytes accelerates adverse cardiac remodeling in response to pressure overload and demonstrated the REV-ERB-independent cardioprotective effect of SR9009 upon pressure overload.

Biscuits, sausage, gravy, milk, and orange juice: school breakfast environment in 4 rural Appalachian schools.

BACKGROUND: The purpose of this study was to assess the school breakfast environment in rural Appalachian schools to inform school environment intervention and policy change. METHODS: A total of 4 rural schools with fourth- and fifth-grade students in East Tennessee were assessed. A cross-sectional descriptive examination of the school food environment where food service managers submitted school menus, production sheets, and vendor bid sheets as part of the dietary data collection protocol for a school-based nutrition intervention study. The school breakfast environment was characterized in terms of calories, fat, saturated fat, and fiber from foods served on a per person basis using menus entered into Nutrient Data Systems for Research and production sheets for amounts of each food item served. Food items were grouped by the meal components of the School Breakfast Program (SBP) and ranked according to the items served most frequently. RESULTS: Total fat provided slightly less than half the calories (43%); 15% of calories were from saturated fat. The top-ranked foods for each meal component were biscuits, sausage, 2% milk, orange juice, and gravy. CONCLUSIONS: Results suggest that clearer policies or regulations for the SBP are warranted to support policy efforts to promote childhood health. These should include technical assistance and provision of resources for school food service managers to provide low-fat meal options. Further research is needed to determine whether what is offered at school breakfast is actually consumed and how that might affect children's weight because of the high fat content.