Alarin moderated myocardial hypertrophy via inhibiting cyclic adenosine monophosphate/protein kinase A signaling pathway to attenuate autophagy

The role of serine/threonine protein kinases in cardiovascular disease and potential therapeutic methods

Protein phosphorylation is an important link in a variety of signaling pathways, and most of the important life processes in cells involve protein phosphorylation. Based on the amino acid residues of phosphorylated proteins, protein kinases can be categorized into the following families: serine/threonine protein kinases, tyrosine-specific protein kinases, histidine-specific protein kinases, tryptophan kinases, and aspartate/glutamyl protein kinases. Of all the protein kinases, most are serine/threonine kinases, where serine/threonine protein kinases are protein kinases that catalyze the phosphorylation of serine or threonine residues on target proteins using ATP as a phosphate donor. The current socially accepted classification of serine/threonine kinases is to divide them into seven major groups: protein kinase A, G, C (AGC), CMGC, Calmodulin-dependent protein kinase (CAMK), Casein kinase (CK1), STE, Tyrosine kinase (TKL) and others. After decades of research, a preliminary understanding of the specific classification and respective functions of serine/threonine kinases has entered a new period of exploration. In this paper, we review the literature of the previous years and introduce the specific signaling pathways and related therapeutic modalities played by each of the small protein kinases in the serine/threonine protein kinase family, respectively, in some common cardiovascular system diseases such as heart failure, myocardial infarction, ischemia-reperfusion injury, and diabetic cardiomyopathy. To a certain extent, the current research results, including molecular mechanisms and therapeutic methods, are fully summarized and a systematic report is made for the prevention and treatment of cardiovascular diseases in the future.

HAPLN1 knockdown inhibits heart failure development via activating the PKA signaling pathway

BACKGROUND

Heart failure (HF) is a heterogeneous syndrome that affects millions worldwide, resulting in substantial health and economic burdens. However, the molecular mechanism of HF pathogenesis remains unclear.

METHODS

HF-related key genes were screened by a bioinformatics approach.The impacts of HAPLN1 knockdown on Angiotensin II (Ang II)-induced AC16 cells were assessed through a series of cell function experiments. Enzyme-linked immunosorbent assay (ELISA) was used to measure levels of oxidative stress and apoptosis-related factors. The HF rat model was induced by subcutaneous injection isoprenaline and histopathologic changes in the cardiac tissue were assessed by hematoxylin and eosin (HE) staining and echocardiographic index. Downstream pathways regulated by HAPLN1 was predicted through bioinformatics and then confirmed in vivo and in vitro by western blot.

RESULTS

Six hub genes were screened, of which HAPLN1, FMOD, NPPB, NPPA, and COMP were overexpressed, whereas NPPC was downregulated in HF. Further research found that silencing HAPLN1 promoted cell viability and reduced apoptosis in Ang II-induced AC16 cells. HAPLN1 knockdown promoted left ventricular ejection fraction (LVEF) and left ventricular fraction shortening (LVFS), while decreasing left ventricular end-systolic volume (LVESV) in the HF rat model. HAPLN1 knockdown promoted the levels of GSH and suppressed the levels of MDA, LDH, TNF-α, and IL-6. Mechanistically, silencing HAPLN1 activated the PKA pathway, which were confirmed both in vivo and in vitro.

CONCLUSION

HAPLN1 knockdown inhibited the progression of HF by activating the PKA pathway, which may provide novel perspectives on the management of HF.

Exogenous galanin alleviates hepatic steatosis by promoting autophagy via the AMPK-mTOR pathway

Defective autophagy-induced intracellular lipid degradation is causally associated with non-alcoholic fatty liver disease (NAFLD) development. Therefore, agents that can restore autophagy may have potential clinical application prospects on this public health issue. Galanin (GAL) is a pleiotropic peptide that regulates autophagy and is a potential drug for the treatment of NAFLD. In this study, we used an MCD-induced NAFLD mouse model in vivo and an FFA-induced HepG2 hepatocyte model in vitro to evaluate the anti-NAFLD effect of GAL. Exogenous GAL supplementation significantly attenuated lipid droplet accumulation and suppressed hepatocyte TG levels in mice and cell models. Mechanistically, Galanin-mediated reduction of lipid accumulation was positively correlated with upregulated p-AMPK, as evidenced by upregulated protein expressions of fatty acid oxidation-related gene markers (PPAR-α and CPT1A), upregulated expressions of the autophagy-related marker (LC3B), and downregulated autophagic substrate p62 levels. In FFA-treated HepG2 cells, activation of fatty acid oxidation and autophagy-related proteins by galanin was reversed by autophagy inhibitors, chloroquine, and the AMPK inhibitor. Galanin ameliorates hepatic fat accumulation by inducing autophagy and fatty acid oxidation via the AMPK/mTOR pathway.

Downregulation of amphiregulin improves cardiac hypertrophy via attenuating oxidative stress and apoptosis

Amphiregulin (AREG) is a ligand of epidermal growth factor receptor and participates in the fibrosis of multiple organs. However, whether AREG can regulate hypertrophic cardiomyopathy is not well known. This research aims to explore the effect of AREG on cardiac hypertrophy, and whether the oxidative stress and apoptosis was involved in the influence of AREG on cardiac hypertrophy. Angiotensin (Ang) II induced cardiac hypertrophy in mice and neonatal rat cardiomyocytes (NRCMs) or HL-1 cells in vitro. AREG expressions raised in the heart of mice. After AREG downregulation, the increases of Ang II induced cardiac weight and cardiomyocytes area were inhibited. Down-regulation of AREG could inhibit Ang II induced the increases of atrial natriuretic peptide, brain natriuretic peptide, beta-myosin heavy chain in the heart of mice, and NRCMs and HL-1 cells. The enhancement of oxidative stress in mice heart with Ang II treatment was alleviated by AREG knockdown. The raises of Ang II induced Bax and cleaved caspase3 in mice heart were inhibited by AREG downregulation. AREG downregulation reduced myocardial hypertrophy via inhibition of oxidative and apoptosis. AREG may be a target for future cardiac hypertrophy treatment.

Myocardial toxicity induced by silica nanoparticles in a transcriptome profile

The deleterious effects of silica nanoparticles (SiNPs) on human health and the ecological system have gradually gained attention owing to their heavy annual output and extensive global flux. The updated epidemiological or experimental investigations have demonstrated the potential myocardial toxicity triggered by SiNPs, but the underlying mechanisms and long-lasting cardiac effects are still poorly understood. Here, a rat model of sub-chronic respiratory exposure to SiNPs was conducted, and the histopathological analysis and ultrastructural investigation of heart tissues were carried out. More importantly, a comprehensive analysis of whole-genome transcription was utilized in rat heart to uncover key biological and cellular mechanisms triggered by SiNPs. The widening of myocardial space and partial fiber rupture were clearly manifested in rat heart after prolonged SiNPs exposure, particularly accompanied by mitochondrial swelling and cristae rupture. With the aid of Affymetrix GeneChips, 3153 differentially expressed genes (DEGs) were identified after SiNPs exposure, including 1916 down- and 1237 up-regulated genes. GO and KEGG analysis illustrated many important biological processes and pathways perturbed by SiNPs, mainly specializing in cellular stress, energy metabolism, actin filament dynamics and immune response. Signal-net analysis revealed that Prkaca (PKA) plays a core role in the cardiac toxification process of prolonged exposure of SiNPs to rats. Furthermore, qRT-PCR verified that PKA-mediated calcium signaling is probably responsible for SiNPs-induced cardiac injury. Conclusively, our study revealed that SiNPs caused myocardial injury, and particularly, provided transcriptomic insight into the role of PKA-calcium signaling triggered by SiNPs, which would facilitate SiNPs-based nanosafety assessment and biomedicine development.