FYCO1 Regulates Cardiomyocyte Autophagy and Prevents Heart Failure Due to Pressure Overload In Vivo

miRNA-103-3p-Hlf regulates apoptosis and autophagy by targeting hepatic leukaemia factor in heart failure

AIMS

Cardiomyocyte apoptosis is an important factor leading to the occurrence and development of heart failure (HF), which is associated with high mortality of patients with cardiovascular diseases. This study aims to investigate the underlying mechanisms of HF in terms of expression and regulation patterns using bioinformatics and experimental validation.

METHODS AND RESULTS

Two HF datasets were collected: a dataset GSE112056 downloaded from the GEO database (including mRNA and miRNA sequencing data) and another is the laboratory-owned mRNA dataset. Differential mRNAs and miRNAs in the two datasets were screened using the raw Bayesian approach method. Gene Ontology was used to perform functional enrichment analysis of the differential mRNAs and co-expression network analysis of the differential mRNAs, combined with nuclear transcription factors in the differential miRNAs and mRNAs for target gene prediction. A HF cell model was constructed using mouse cardiomyocytes (HL-1), and the role and mechanism of miRNA-103-3p-Hlf (hepatic leukaemia factor) in the process of HF was verified by cell transfection, luciferase reporter gene, WB, and qPCR. We found that Hlf gene expression was decreased in the HF model group and strongly correlated with FYCO1 (FYVE and coiled-coil domain-containing protein 1) gene, a phenomenon enriched in apoptotic autophagy-related pathways. MiR-103-3p expression was up-regulated in the HF model group, and its targeting correlation with Hlf was confirmed by luciferase activity assay. In the HL-1 cell model, miR-103-3p significantly promoted apoptosis and inhibited autophagy in HL-1 cells (all P < 0.05), and overexpression of the Hlf gene reversed this phenomenon, inhibiting apoptosis and promoting autophagy in HL-1 cells (all P < 0.05).

CONCLUSIONS

MiR-103-3p affects myocardial cells apoptosis and autophagy by targeting Hlf, playing as a potential therapeutic biomarker for HF progression.

Autophagy, innate immunity, and cardiac disease

Autophagy is an evolutionarily conserved mechanism of cell adaptation to metabolic and environmental stress. It mediates the disposal of protein aggregates and dysfunctional organelles, although non-conventional features have recently emerged to broadly extend the pathophysiological relevance of autophagy. In baseline conditions, basal autophagy critically regulates cardiac homeostasis to preserve structural and functional integrity and protect against cell damage and genomic instability occurring with aging. Moreover, autophagy is stimulated by multiple cardiac injuries and contributes to mechanisms of response and remodeling following ischemia, pressure overload, and metabolic stress. Besides cardiac cells, autophagy orchestrates the maturation of neutrophils and other immune cells, influencing their function. In this review, we will discuss the evidence supporting the role of autophagy in cardiac homeostasis, aging, and cardioimmunological response to cardiac injury. Finally, we highlight possible translational perspectives of modulating autophagy for therapeutic purposes to improve the care of patients with acute and chronic cardiac disease.

Nicotinamide riboside kinase-2 regulates metabolic adaptation in the ischemic heart

Ischemia-induced metabolic remodeling plays a critical role in the pathogenesis of adverse cardiac remodeling and heart failure however, the underlying molecular mechanism is largely unknown. Here, we assess the potential roles of nicotinamide riboside kinase-2 (NRK-2), a muscle-specific protein, in ischemia-induced metabolic switch and heart failure through employing transcriptomic and metabolomic approaches in ischemic NRK-2 knockout mice. The investigations revealed NRK-2 as a novel regulator of several metabolic processes in the ischemic heart. Cardiac metabolism and mitochondrial function and fibrosis were identified as top dysregulated cellular processes in the KO hearts post-MI. Several genes linked to mitochondrial function, metabolism, and cardiomyocyte structural proteins were severely downregulated in the ischemic NRK-2 KO hearts. Analysis revealed significantly upregulated ECM-related pathways which was accompanied by the upregulation of several key cell signaling pathways including SMAD, MAPK, cGMP, integrin, and Akt in the KO heart post-MI. Metabolomic studies identified profound upregulation of metabolites mevalonic acid, 3,4-dihydroxyphenylglycol, 2-penylbutyric acid, and uridine. However, other metabolites stearic acid, 8,11,14-eicosatrienoic acid, and 2-pyrrolidinone were significantly downregulated in the ischemic KO hearts. Taken together, these findings suggest that NRK-2 promotes metabolic adaptation in the ischemic heart. The aberrant metabolism in the ischemic NRK-2 KO heart is largely driven by dysregulated cGMP and Akt and mitochondrial pathways. KEY MESSAGES: Post-myocardial infarction metabolic switch critically regulates the pathogenesis of adverse cardiac remodeling and heart failure. Here, we report NRK-2 as a novel regulator of several cellular processes including metabolism and mitochondrial function post-MI. NRK-2 deficiency leads to downregulation of genes important for mitochondrial pathway, metabolism, and cardiomyocyte structural proteins in the ischemic heart. It was accompanied by upregulation of several key cell signaling pathways including SMAD, MAPK, cGMP, integrin, and Akt and dysregulation of numerous metabolites essential for cardiac bioenergetics. Taken together, these findings suggest that NRK-2 is critical for metabolic adaptation of the ischemic heart.

The role of the Hippo pathway in autophagy in the heart

The Hippo pathway, an evolutionarily conserved signalling mechanism, controls organ size and tumourigenesis. Increasing lines of evidence suggest that autophagy, an important mechanism of lysosome-mediated cellular degradation, is regulated by the Hippo pathway, which thereby profoundly affects cell growth and death responses in various cell types. In the heart, Mst1, an upstream component of the Hippo pathway, not only induces apoptosis but also inhibits autophagy through phosphorylation of Beclin 1. YAP/TAZ, transcription factor co-factors and the terminal effectors of the Hippo pathway, affect autophagy through transcriptional activation of TFEB, a master regulator of autophagy and lysosomal biogenesis. The cellular abundance of YAP is negatively regulated by autophagy and suppression of autophagy induces accumulation of YAP, which, in turn, acts as a feedback mechanism to induce autophagosome formation. Thus, the Hippo pathway and autophagy regulate each other, thereby profoundly affecting cardiomyocyte survival and death. This review discusses the interaction between the Hippo pathway and autophagy and its functional significance during stress conditions in the heart and the cardiomyocytes therein.

The role of FYCO1-dependent autophagy in lens fiber cell differentiation

FYCO1 (FYVE and coiled-coil domain containing 1) is an adaptor protein, expressed ubiquitously and required for microtubule-dependent, plus-end-directed transport of macroautophagic/autophagic vesicles. We have previously shown that loss-of-function mutations in FYCO1 cause cataracts with no other ocular and/or extra-ocular phenotype. Here, we show fyco1 homozygous knockout (fyco1-/-) mice recapitulate the cataract phenotype consistent with a critical role of FYCO1 and autophagy in lens morphogenesis. Transcriptome coupled with proteome and metabolome profiling identified many autophagy-associated genes, proteins, and lipids respectively perturbed in fyco1-/- mice lenses. Flow cytometry of FYCO1 (c.2206C>T) knock-in (KI) human lens epithelial cells revealed a decrease in autophagic flux and autophagic vesicles resulting from the loss of FYCO1. Transmission electron microscopy showed cellular organelles accumulated in FYCO1 (c.2206C>T) KI lens-like organoid structures and in fyco1-/- mice lenses. In summary, our data confirm the loss of FYCO1 function results in a diminished autophagic flux, impaired organelle removal, and cataractogenesis.Abbreviations: CC: congenital cataracts; DE: differentially expressed; ER: endoplasmic reticulum; FYCO1: FYVE and coiled-coil domain containing 1; hESC: human embryonic stem cell; KI: knock-in; OFZ: organelle-free zone; qRT-PCR: quantitative real-time PCR; PE: phosphatidylethanolamine; RNA-Seq: RNA sequencing; SD: standard deviation; sgRNA: single guide RNA; shRNA: shorthairpin RNA; TEM: transmission electron microscopy; WT: wild type.

The Genomic Profile Associated with Risk of Severe Forms of COVID-19 in Amazonian Native American Populations

Genetic factors associated with COVID-19 disease outcomes are poorly understood. This study aimed to associate genetic variants in the SLC6A20, LZTFL1, CCR9, FYCO1, CXCR6, XCR1, and ABO genes with the risk of severe forms of COVID-19 in Amazonian Native Americans, and to compare the frequencies with continental populations. The study population was composed of 64 Amerindians from the Amazon region of northern Brazil. The difference in frequencies between the populations was analyzed using Fisher’s exact test, and the results were significant when p ≤ 0.05. We investigated 64 polymorphisms in 7 genes; we studied 47 genetic variants that were new or had impact predictions of high, moderate, or modifier. We identified 15 polymorphisms with moderate impact prediction in 4 genes (ABO, CXCR6, FYCO1, and SLC6A20). Among the variants analyzed, 18 showed significant differences in allele frequency in the NAM population when compared to others. We reported two new genetic variants with modifier impact in the Amazonian population that could be studied to validate the possible associations with COVID-19 outcomes. The genomic profile of Amazonian Native Americans may be associated with protection from severe forms of COVID-19. This work provides genomic data that may help forthcoming studies to improve COVID-19 outcomes.