Pressure overload promotes cystatin C secretion of cardiomyocytes to regulate the MAPK signaling pathway and mediate cardiac hypertrophy

Poly (ADP-ribose) polymerases 16 triggers pathological cardiac hypertrophy via activating IRE1α-sXBP1-GATA4 pathway

BACKGROUND

Pressure overload-induced pathological cardiac hypertrophy is an independent predecessor of heart failure (HF), which remains the leading cause of worldwide mortality. However, current evidence on the molecular determinants of pathological cardiac hypertrophy is still inadequacy. This study aims to elucidate the role and mechanisms of Poly (ADP-ribose) polymerases 16 (PARP16) in the pathogenesis of pathological cardiac hypertrophy.

METHODS

Gain and loss of function approaches were used to demonstrate the effects of genetic overexpression or deletion of PARP16 on cardiomyocyte hypertrophic growth in vitro. Ablation of PARP16 by transducing the myocardium with serotype 9 adeno-associated virus (AAV9)-encoding PARP16 shRNA were then subjected to transverse aortic construction (TAC) to investigate the effect of PARP16 on pathological cardiac hypertrophy in vivo. Co-immunoprecipitation (IP) and western blot assay were used to detect the mechanisms of PARP16 in regulating cardiac hypertrophic development.

RESULTS

PARP16 deficiency rescued cardiac dysfunction and ameliorated TAC-induced cardiac hypertrophy and fibrosis in vivo, as well as phenylephrine (PE)-induced cardiomyocyte hypertrophic responses in vitro. Whereas overexpression of PARP16 exacerbated hypertrophic responses including the augmented cardiomyocyte surface area and upregulation of the fetal gene expressions. Mechanistically, PARP16 interacted with IRE1α and ADP-ribosylated IRE1α and then mediated the hypertrophic responses through activating the IRE1α-sXBP1-GATA4 pathway.

CONCLUSIONS

Collectively, our results implicated that PARP16 is a contributor to pathological cardiac hypertrophy at least in part via activating the IRE1α-sXBP1-GATA4 pathway, and may be regarded as a new potential target for exploring effective therapeutic interventions of pathological cardiac hypertrophy and heart failure.

Association between serum cystatin C and early impairment of cardiac function and structure in type 2 diabetes patients with normal renal function

BACKGROUND

Type 2 diabetes mellitus (T2DM) patients may have cardiac remodeling and dysfunction from the early stage of disease. This study aimed to determine the association between cystatin C (CysC) and early cardiac functional or structural impairment in T2DM patients without renal dysfunction.

METHODS

A total of 1135 T2DM patients without renal dysfunction and known heart diseases were included in our study. Cardiac function and structure were evaluated by echocardiography. Patients were diagnosed as left ventricular hypertrophy (LVH), impaired left ventricular (LV) diastolic function, and categorized into four different LV geometry patterns including normal, concentric remodeling, concentric hypertrophy, and eccentric hypertrophy.

RESULTS

In multivariate linear regression analyses, CysC was positively associated with interventricular septum, LV mass index, left atrial volume index, E/e' ratio, and negatively associated with Tissue Doppler e', E/A ratio (p < .05). As a continuous variable, increasing CysC levels were associated with prevalence of LVH (OR: 1.47, 95% confidence interval [CI]: 1.22-1.77), impaired LV diastolic function (OR: 1.58, 95% CI: 1.33-1.87), concentric hypertrophy (OR: 1.54, 95% CI: 1.23-1.93) and eccentric hypertrophy (OR: 1.34, 95% CI: 1.00-1.80) according to multivariate logistic regression analyses. While as a categorical variable, the highest CysC quartile (CysC > 1.04 mg/L) was associated with LVH (OR: 2.95, 95% CI: 1.74-5.00), impaired LV diastolic function (OR: 4.09, 95% CI: 2.54-6.60), and concentric hypertrophy (OR: 3.26, 95% CI: 2.05-5.18).

CONCLUSIONS

CysC was significantly associated with early LV remodeling and cardiac functional impairment in T2DM patients with normal renal function. It could be a reliable and convenient biomarker detecting early impairment of cardiac function and structure in T2DM patients.

Inflammatory serum factors from aortic valve stenosis patients modulate sex differences in valvular myofibroblast activation and osteoblast-like differentiation

Aortic valve stenosis (AVS) is a sexually dimorphic cardiovascular disease that is driven by fibrosis and calcification of the aortic valve leaflets. Circulating inflammatory factors present in serum from AVS patients contribute to sex differences in valve fibro-calcification by driving the activation of valvular interstitial cells (VICs) to myofibroblasts and/or osteoblast-like cells. However, the molecular mechanisms by which inflammatory factors contribute to sex-specific valve fibro-calcification remain largely unknown. In this study, we identified inflammatory factors present in serum samples from AVS patients that regulate sex-specific myofibroblast activation and osteoblast-like differentiation. After correlating serum proteomic datasets with clinical and in vitro myofibroblast datasets, we identified annexin A2 and cystatin C as candidate inflammatory factors that correlate with both AVS patient severity and myofibroblast activation measurements in vitro. Validation experiments utilizing hydrogel biomaterials as cell culture platforms that mimic the valve extracellular matrix confirmed that annexin A2 and cystatin C promote sex-specific VIC activation to myofibroblasts via p38 MAPK signaling. Additionally, annexin A2 and cystatin C increase osteoblast-like differentiation primarily in male VICs. Our results implicate serum inflammatory factors as potential AVS biomarkers that also contribute to sexually dimorphic AVS progression by driving VIC myofibroblast activation and/or osteoblast-like differentiation. Collectively, the results herein further our overall understanding as to how biological sex may impact inflammation-driven AVS and may lead to the development of sex-specific drug treatment strategies.

The independent and interactive effects of phthalates exposure and hypertension on the indicators of early renal injury in US adults: Evidence from NHANES 2001-2004

The association between phthalates and early renal injury is largely unknown in adults. We aim to explore the associations of phthalates and hypertension with early renal injury, and the interactive effects of phthalate and hypertension on the early renal injury. This study enrolled 3283 U.S. adults from NHANES 2001-2004. We detected nine phthalate metabolites in spot urine. We also measured the multiple indicators of early renal injury, including albumin-to-creatinine (Cr) ratio (ACR), β2-microglobulin (B2M), cystatin C (CYST), and calculated the estimated glomerular filtration rate (eGFR), including Cr-based eGFR, CYST-based eGFR, and Cr-CYST-based eGFR. Multiple linear regression and multivariable logistic regression were used to explore the associations among urinary phthalate metabolites, hypertension, and the indicators of early renal injury. The results showed that monobenzyl phthalate (MBzP), mono (3-carboxypropyl) phthalate (MCPP), and mono (2-ethylhexyl) phthalate (MEHP) were positively associated with ACR, B2M, CYST and negatively associated with three eGFR. Mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) was positively associated with ACR, with a β value of 0.099 (95% CI: 0.046, 0.152). Meanwhile, MEHP was associated with a higher risk of ACR abnormality, with an OR value of 1.258 (95% CI: 1.067, 1.482). MBzP, MCPP, and MEOHP increased the risks of ACR, B2M, CYST, and eGFR abnormality. Hypertension was positively associated with ACR, with a β value of 0.460 (95% CI: 0.360, 0.561). We also found interactive effects of monoethyl phthalate (MEP), MCPP, MBzP, monobutyl phthalate (MnBP), and hypertension on B2M, CYST, and three kinds of eGFR. Our results indicated that certain phthalate metabolites might contribute to increased risks of early renal injury. The hypertension population may be more sensitive to the early renal injury caused by phthalates exposure than the non-hypertension population.

VPO1/HOCl/ERK pathway mediates the right ventricular remodeling in rats with hypoxic pulmonary hypertension

Right ventricular (RV) remodeling is a major feature of pulmonary arterial hypertension (PAH). Vascular peroxidase 1 (VPO1) is reported to participate in the process of PAH. This study aims to explore whether VPO1 contributes to hypoxia-induced cardiac hypertrophy and the underlying mechanisms. SD rats were exposure to continuous hypoxia (10% O₂) for 3 weeks, which showed RV hypertrophy (increases in the ratio of RV weight to tibia length, cardiac cell size and hypertrophic markers), concomitant with upregulation of VPO1, elevation in hypochlorous acid (HOCl) production and ERK phosphorylation. In hypoxia (3% O₂)-induced hypertrophic H9c2 cells, similar characteristics of cardiac hypertrophy to that of hypoxia-treated rats were observed. Administration of VPO1 siRNA or NaHS (the HOCl inhibitor) suppressed HOCl production, ERK phosphorylation, and cardiac hypertrophy. Replacement of hypoxia with NaClO (exogenous HOCl) could also induce cardiac cell hypertrophy and activate ERK signaling pathway. In addition, hypoxia-induced cardiac hypertrophy could be blocked by PD98059 (the ERK-specific inhibitor). Based on these observations, we conclude that VPO1 promotes RV remodeling in PAH rats through catalyzing HOCl production, leading to the activation of ERK signaling. Thus, VPO1 may have the potential as a therapeutic target for PAH.

Fibroblast Growth Factor-23-Klotho Axis in Cardiorenal Syndrome: Mediators and Potential Therapeutic Targets

Cardiorenal syndrome (CRS) is a complex disorder that refers to the category of acute or chronic kidney diseases that induce cardiovascular disease, and inversely, acute or chronic heart diseases that provoke kidney dysfunction. There is a close relationship between renal and cardiovascular disease, possibly due to the presence of common risk factors for both diseases. Thus, it is well known that renal diseases are associated with increased risk of developing cardiovascular disease, suffering cardiac events and even mortality, which is aggravated in those patients with end-stage renal disease or who are undergoing dialysis. Recent works have proposed mineral bone disorders (MBD) as the possible link between kidney dysfunction and the development of cardiovascular outcomes. Traditionally, increased serum phosphate levels have been proposed as one of the main factors responsible for cardiovascular damage in kidney patients. However, recent studies have focused on other MBD components such as the elevation of fibroblast growth factor (FGF)-23, a phosphaturic bone-derived hormone, and the decreased expression of the anti-aging factor Klotho in renal patients. It has been shown that increased FGF-23 levels induce cardiac hypertrophy and dysfunction and are associated with increased cardiovascular mortality in renal patients. Decreased Klotho expression occurs as renal function declines. Despite its expression being absent in myocardial tissue, several studies have demonstrated that this antiaging factor plays a cardioprotective role, especially under elevated FGF-23 levels. The present review aims to collect the recent knowledge about the FGF-23-Klotho axis in the connection between kidney and heart, focusing on their specific role as new therapeutic targets in CRS.

Relationship between HSPA1A-regulated gene expression and alternative splicing in mouse cardiomyocytes and cardiac hypertrophy

Background

Cardiac hypertrophy may be classified as either physiological or pathological. Pathological hypertrophy has a complex etiology and is genetically regulated. In this study, we used a mouse model of cardiac hypertrophy to explore the mechanisms of gene regulation, in particular, modulation of the expression of target genes through transcription factor activity, regulation of immune and inflammation-associated genes and regulation of the alternative splicing of transcription factors.

Methods

Mouse models of pathological cardiac hypertrophy were established by transverse aortic constriction (TAC). We overexpressed HSPA1A in mouse cardiac HL-1 cells. GO and KEGG pathway annotation database was used to analyze all DEGs.

Results

The expression of HSPA1A differed significantly between TAC + dantrolene vs. sham + dantrolene (Sham was the non-TAC group, and DMSO was the contrast agent), and TAC + DMSO vs. sham + DMSO. The RNA-binding protein Zfp36 was found to be differentially expressed between both TAC + dantrolene vs. sham + dantrolene and TAC + DMSO vs. sham + DMSO. The expression of mki67 and gm5619 was significantly different between TAC + dantrolene and TAC + DMSO. HSPA1A was found to selectively regulate the expression of non-coding RNAs related to cardiac hypertrophy, including Rn7sk and RMRP. The downregulated genes were mainly related to inflammation and the immune response. HSPA1A negatively regulated alternative splicing of Asxl2 and positively regulated alternative splicing of Runx1.

Conclusions

HSPA1A was closely related to cardiac hypertrophy. Zfp36 was also related to cardiac hypertrophy. Dantrolene may delay cardiac hypertrophy and ventricular remodeling by regulating the expression of the RNA-binding protein genes mki67 and gm5619. HSPA1A positively regulated the expression of the non-coding RNAs RN7SK and RMRP while negatively regulating the expression of inflammation- and immune response-related genes. HSPA1A can play a role in cardiac hypertrophy by regulating the alternative splicing of asxl2 and runx1.

Bevacizumab-Induced Mitochondrial Dysfunction, Endoplasmic Reticulum Stress, and ERK Inactivation Contribute to Cardiotoxicity

The molecular mechanisms underlying the cardiotoxicity associated with bevacizumab, a first-line immunotherapeutic agent used to treat lung cancer, are not fully understood. Here, we examined intracellular signal transduction in cardiomyocytes after exposure to different doses of bevacizumab in vitro. Our results demonstrated that bevacizumab significantly and dose-dependently reduces cardiomyocyte viability and increases cell apoptosis. Bevacizumab treatment also led to mitochondrial dysfunction in cardiomyocytes, as evidenced by the decreased ATP production, increased ROS production, attenuated antioxidative enzyme levels, and reduced respiratory complex function. In addition, bevacizumab induced intracellular calcium overload, ER stress, and caspase-12 activation. Finally, bevacizumab treatment inhibited the ERK signaling pathway, which, in turn, significantly reduced cardiomyocyte viability and contributed to mitochondrial dysfunction. Together, our results demonstrate that bevacizumab-mediated cardiotoxicity is associated with mitochondrial dysfunction, ER stress, and ERK pathway inactivation. These findings may provide potential treatment targets to attenuate myocardial injury during lung cancer immunotherapy.