Novel Role for Pleckstrin Homology-Like Domain Family A, Member 3 in the Regulation of Pathological Cardiac Hypertrophy

Berberine ameliorates chronic intermittent hypoxia-induced cardiac remodelling by preserving mitochondrial function, role of SIRT6 signalling

Chronic intermittent hypoxia (CIH) is associated with an increased risk of cardiovascular diseases. Previously, we have shown that berberine (BBR) is a potential cardioprotective agent. However, its effect and mechanism on CIH-induced cardiomyopathy remain uncovered. This study was designed to determine the effects of BBR against CIH-induced cardiac damage and to explore the molecular mechanisms. Mice were exposed to 5 weeks of CIH with or without the treatment of BBR and adeno-associated virus 9 (AAV9) carrying SIRT6 or SIRT6-specific short hairpin RNA. The effect of BBR was evaluated by echocardiography, histological analysis and western blot analysis. CIH caused the inactivation of myocardial SIRT6 and AMPK-FOXO3a signalling. BBR dose-dependently ameliorated cardiac injury in CIH-induced mice, as evidenced by increased cardiac function and decreased fibrosis. Notably, SIRT6 overexpression mimicked these beneficial effects, whereas infection with recombinant AAV9 carrying SIRT6-specific short hairpin RNA abrogated them. Mechanistically, BBR reduced oxidative stress damage and preserved mitochondrial function via activating SIRT6-AMPK-FOXO3a signalling, enhancing mitochondrial biogenesis as well as PINK1-Parkin-mediated mitophagy. Taken together, these data demonstrate that SIRT6 activation protects against the pathogenesis of CIH-induced cardiac dysfunction. BBR attenuates CIH-induced myocardial injury by improving mitochondrial biogenesis and PINK1-Parkin-dependent mitophagy via the SIRT6-AMPK-FOXO3a signalling pathway.

Multiomics Analysis of the PHLDA Gene Family in Different Cancers and Their Clinical Prognostic Value

The PHLDA (pleckstrin homology-like domain family) gene family is popularly known as a potential biomarker for cancer identification, and members of the PHLDA family have become considered potentially viable targets for cancer treatments. The PHLDA gene family consists of PHLDA1, PHLDA2, and PHLDA3. The predictive significance of PHLDA genes in cancer remains unclear. To determine the role of pleckstrin as a prognostic biomarker in human cancers, we conducted a systematic multiomics investigation. Through various survival analyses, pleckstrin expression was evaluated, and their predictive significance in human tumors was discovered using a variety of online platforms. By analyzing the protein-protein interactions, we also chose a collection of well-known functional protein partners for pleckstrin. Investigations were also carried out on the relationship between pleckstrins and other cancers regarding mutations and copy number alterations. The cumulative impact of pleckstrin and their associated genes on various cancers, Gene Ontology (GO), and pathway analyses were used for their evaluation. Thus, the expression profiles of PHLDA family members and their prognosis in various cancers may be revealed by this study. During this multiomics analysis, we found that among the PHLDA family, PHLDA1 may be a therapeutic target for several cancers, including kidney, colon, and brain cancer, while PHLDA2 can be a therapeutic target for cancers of the colon, esophagus, and pancreas. Additionally, PHLDA3 may be a useful therapeutic target for ovarian, renal, and gastric cancer.

Inhibition of Sema4D attenuates pressure overload-induced pathological myocardial hypertrophy via the MAPK/NF-κB/NLRP3 pathways

Sema4D (CD100) is closely related to pathological and physiological processes, including tumor growth, angiogenesis and cardiac development. Nevertheless, the role and mechanism of Sema4D in cardiac hypertrophy are still unclear to date. To assess the impact of Sema4D on pathological cardiac hypertrophy, TAC surgery was performed on C57BL/6 mice which were transfected with AAV9-mSema4D-shRNA or AAV9-mSema4D adeno-associated virus by tail vein injection. Our results indicated that Sema4D knockdown mitigated cardiac hypertrophy, fibrosis and dysfunction when exposed to pressure overload, and Sema4D downregulation markedly inhibited cardiomyocyte hypertrophy induced by angiotensin II. Meanwhile, Sema4D overexpression had the opposite effect in vitro and in vivo. Furthermore, analysis of signaling pathways showed that Sema4D activated the MAPK pathway during cardiac hypertrophy induced by pressure overload, and the pharmacological mitogen-activated protein kinase kinase 1/2 inhibitor U0126 almost completely reversed Sema4D overexpression-induced deteriorated phenotype, resulting in improved cardiac function. Further research indicated that myocardial hypertrophy induced by Sema4D was closely related to the expression of the pyroptosis-related proteins PP65, NLRP3, caspase-1, ASC, GSDMD, IL-18 and IL-1β. In conclusion, our study demonstrated that Sema4D regulated the process of pathological myocardial hypertrophy through modulating MAPK/NF-κB/NLRP3 pathway, and Sema4D may be the promising interventional target of cardiac hypertrophy and heart failure.

New insights into the effect of VMP1 on the treatment of pressure overload-induced pathological cardiac hypertrophy: Involving SERCA-regulated autophagic flux

Pathological cardiac hypertrophy is an adaptive reaction in response to pressure or volume overload. Autophagy is critical for damage caused by pathological cardiac hypertrophy. Vacuole membrane protein 1 (VMP1) is an endoplasmic reticulum (ER) transmembrane protein that is effective in activating autophagy. However, the role of VMP1 in pathological cardiac hypertrophy and its underlying mechanisms remain elusive. This study was designed to explore the potential mechanisms of VMP1 on pressure overload-induced pathological cardiac hypertrophy. In this work, abdominal aorta constriction (AAC) surgery was used to induce pathological cardiac hypertrophy in male C57BL/6 mice. H9C2 cardiomyocytes were treated with phenylephrine stimulation (PE) to induce the hypertrophic response. The in vivo results revealed that mice with AAC surgery caused pathological cardiac hypertrophy as evidenced by improved cardiac function according to multiple echocardiographic parameters. Moreover, elevated VMP1 expression was also observed in mice after AAC surgery. VMP1 knockdown aggravated changes in cardiac structure, cardiac dysfunction, and fibrosis. Meanwhile, VMP1 knockdown suppressed autophagy and endoplasmic reticulum calcium ATPase (SERCA) activity in heart tissues. H9C2 cardiomyocytes with VMP1 overexpression were used to investigate the specific mechanism of VMP1 in pathological cardiac hypertrophy, and VMP1 overexpression increased autophagic flux by upregulating SERCA activity. In conclusion, these findings revealed that VMP1 protected against pressure overload-induced pathological cardiac hypertrophy by inducing SERCA-regulated autophagic flux. Our results provide valuable insights regarding the pathophysiology of pathological cardiac hypertrophy and clues to a novel target for the treatment of pathological cardiac hypertrophy.

Polydatin attenuates chronic alcohol consumption-induced cardiomyopathy through a SIRT6-dependent mechanism

Polydatin has attracted much attention as a potential cardioprotective agent against ischemic heart disease and diabetic cardiomyopathy. However, the effect and mechanism of polydatin supplementation on alcoholic cardiomyopathy (ACM) are still unknown. This study aimed to determine the therapeutic effect of polydatin against ACM and to explore the molecular mechanisms with a focus on SIRT6-AMP-activated protein kinase (AMPK) signaling and mitochondrial function. The ACM model was established by feeding C57/BL6 mice with an ethanol Lieber-DeCarli diet for 12 weeks. The mice received polydatin (20 mg kg^-1) or vehicle treatment. We showed that polydatin treatment not only improved cardiac function but also reduced myocardial fibrosis and dynamin-related protein 1 (Drp-1)-mediated mitochondrial fission, and enhanced PTEN-induced putative kinase 1 (PINK1)-Parkin-dependent mitophagy in alcohol-treated myocardium. Importantly, these beneficial effects were mimicked by SIRT6 overexpression but abolished by the infection of recombinant serotype 9 adeno-associated virus (AAV9) carrying SIRT6-specific small hairpin RNA. Mechanistically, alcohol consumption induced a gradual decrease in the myocardial SIRT6 level, while polydatin effectively activated SIRT6-AMPK signaling and modulated mitochondrial dynamics and mitophagy, thus reducing oxidative stress damage and preserving mitochondrial function. In summary, these data present new information regarding the therapeutic actions of polydatin, suggesting that the activation of SIRT6 signaling may represent a new approach for tackling ACM-related cardiac dysfunction.

Pleckstrin homology-like domain family A, member 3, a miR-19a-3p-regulated gene, suppresses tumor growth in osteosarcoma by downregulating the Akt pathway

Pleckstrin homology-like domain family A, member 3 (PHLDA3), is emerging as a critical regulator for multiple cancers. Nevertheless, the expression and role of PHLDA3 in osteosarcoma remain unknown. Herein, we purposed to elucidate the role of PHLDA3 in the progression and chemoresistance of osteosarcoma. According to the bioinformatics analysis, PHLDA3 expression was low in osteosarcoma patients, and low content was linked to poor prognosis. Additionally, activation of PHLDA3 suppressed osteosarcoma cell proliferation, migration, and chemoresistance, whereas PHLDA3 inhibition caused the opposite effects. Mechanistically, our data revealed that PHLDA3 negatively regulates the Akt/GSK3β signaling cascade in osteosarcoma. Furthermore, we found that miR-19a-3p might exert its oncogenic function by inhibiting PHLDA3 expression in osteosarcoma. These results demonstrated miR-19a-3p/ PHLDA3/ Akt/GSK3β axis has a pivotal role in osteosarcoma, and PHLDA3 is a prospective therapeutic target for treating osteosarcoma.

Activation of PKG-CREB-KLF15 by melatonin attenuates Angiotensin II-induced vulnerability to atrial fibrillation via enhancing branched-chain amino acids catabolism

Mitochondrial reactive oxygen species (ROS) damage and atrial remodeling serve as the crucial substrates for the genesis of atrial fibrillation (AF). Branched-chain amino acids (BCAAs) catabolic defect plays critical roles in multiple cardiovascular diseases. However, the alteration of atrial BCAA catabolism and its role in AF remain largely unknown. This study aimed to explore the role of BCAA catabolism in the pathogenesis of AF and to further evaluate the therapeutic effect of melatonin with a focus on protein kinase G (PKG)-cAMP response element binding protein (CREB)-Krüppel-like factor 15 (KLF15) signaling. We found that angiotensin II-treated atria exhibited significantly elevated BCAA level, reduced BCAA catabolic enzyme activity, increased AF vulnerability, aggravated atrial electrical and structural remodeling, and enhanced mitochondrial ROS damage. These deleterious effects were attenuated by melatonin co-administration while exacerbated by BCAA oral supplementation. Melatonin treatment ameliorated BCAA-induced atrial damage and reversed BCAA-induced down-regulation of atrial PKGIα expression, CREB phosphorylation as well as KLF15 expression. However, inhibition of PKG partly abolished melatonin-induced beneficial actions. In summary, these data demonstrated that atrial BCAA catabolic defect contributed to the pathogenesis of AF by aggravating tissue fibrosis and mitochondrial ROS damage. Melatonin treatment ameliorated Ang II-induced atrial structural as well as electrical remodeling by activating PKG-CREB-KLF15. The present study reveals additional mechanisms contributing to AF genesis and highlights the opportunity of a novel therapy for AF by targeting BCAA catabolism. Melatonin may serve as a potential therapeutic agent for AF intervention.

Sleeve Gastrectomy Ameliorates Diabetes-Induced Cardiac Hypertrophy Correlates With the MAPK Signaling Pathway

Background: Cardiac hypertrophy as a main pathological manifestation of diabetic cardiomyopathy (DCM), is a significant complication of diabetes. Bariatric surgery has been proven to relieve DCM; however, whether it can alleviate diabetes-induced cardiac hypertrophy is undefined.

Methods: Diabetic and obese rats were performed sleeve gastrectomy (SG) after having diabetes for 16weeks. The rats were euthanized 8weeks after SG. Metabolic parameters, heart function parameters, myocardial glucose uptake, morphometric and histological changes, and the expression level of mitogen-activated protein kinases (MAPKs) were determined and compared among the control group (CON group), diabetes mellitus group (DM group), sham operation group (SHAM group), and SG group.

Results: Compared with the SHAM group, the blood glucose, body weight, insulin resistance, and other metabolic parameters were significantly improved in the SG group. There was also a marked improvement in myocardial morphometric and histological parameters after SG. Furthermore, the myocardial glucose uptake and heart function were reversed after SG. Additionally, the phosphorylation of MAPKs was inhibited after SG, including p38 MAPKs, c-Jun N-terminal kinases (JNKs), and extracellular signal-regulated kinases 1/2 (ERK1/2). The expression of DUSP6, which dephosphorylates ERK1/2, was upregulated after SG. These findings suggest that SG ameliorated diabetes-induced cardiac hypertrophy correlates with the MAPK signaling pathway.

Conclusion: These results showed that diabetes-induced cardiac hypertrophy was ameliorated after SG was closely related to the inhibition of the MAPK signaling pathway and upregulation of DUSP6. Therefore, this study provides a novel strategy for treating diabetes-induced cardiac hypertrophy.

PHLDA3 inhibition protects against myocardial ischemia/reperfusion injury by alleviating oxidative stress and inflammatory response via the Akt/Nrf2 axis

Pleckstrin homology-like domain family A, member 3 (PHLDA3) has a particularly critical role in regulating cell survival under stress conditions. However, whether PHLDA3 plays a role in myocardial ischemia/reperfusion injury has not been studied. We aimed to assess the possible role of PHLDA3 in myocardial ischemia/reperfusion (I/R) injury. PHLDA3 expression was increased in myocardial tissue from rats with myocardial I/R injury and rat cardiomyocytes with hypoxia/reoxygenation (H/R) injury. PHLDA3 knockdown protected against myocardial I/R injury in vivo and H/R injury in vitro. Inhibition of PHLDA3 increased the activation of nuclear factor erythroid-derived 2-related factor 2 (Nrf2) associated with regulation of the Akt/glycogen synthase kinase-3β (GSK-3β) axis. Repression of Nrf2 reversed PHLDA3-inhibition-mediated cardioprotective effects. Taken together, our work demonstrates that PHLDA3 inhibition exerts a protective role in myocardial I/R injury via regulation of the Akt/GSK-3β/Nrf2 axis. We suggest PHLDA3 as an attractive target for developing treatments against myocardial I/R injury.

PHLDA3 promotes lung adenocarcinoma cell proliferation and invasion via activation of the Wnt signaling pathway

The PHLDA3 gene encodes a small 127 amino acid protein with a pleckstrin homology (PH)-only domain. The expression and significance of PHLDA3 in lung cancer remain unclear. Here, we investigated the role of PHLDA3 in tumor proliferation and invasion in lung adenocarcinoma. Immunohistochemistry and immunoblotting analyses were used to assess PHLDA3 expression in lung cancer tissues, and its correlation with clinicopathological factors in lung cancer. Plasmids encoding PHLDA3 and small interfering RNA against PHLDA3 were used to regulate the expression of PHLDA3 in lung cancer cells. Furthermore, the effects of PHLDA3 on lung cancer cell proliferation and invasion were investigated using the MTS, colony formation, Matrigel invasion, and wound healing assays. Co-immunoprecipitation analysis and inhibitors of both the Wnt signaling pathway and GSK3β were used to explore the regulatory mechanisms underlying the role of PHLDA3 in lung cancer cells. PHLDA3 was found to be overexpressed in lung cancer tissues, and its expression was correlated with poor outcomes in lung adenocarcinoma patients. PHLDA3 expression promoted the proliferation, invasion, and migration of lung cancer cells. Overexpression of PHLDA3 activated the Wnt signaling pathway and facilitated epithelial-mesenchymal transition. Inhibition of Wnt signaling pathway activity, using XAV-939, reversed the effects of PHLDA3 overexpression in lung cancer cells; moreover, PHLDA3 could bind to GSK3β. Inhibition of GSK3β activity, using CHIR-99021, restored the proliferative and invasive abilities of PHLDA3 knockdown cells. Our findings demonstrate that PHLDA3 is highly expressed in lung adenocarcinomas and is correlated with poor outcomes. Furthermore, it promotes the proliferation and invasion of lung cancer cells by activating the Wnt signaling pathway.

Inhibition of TNFAIP1 ameliorates the oxidative stress and inflammatory injury in myocardial ischemia/reperfusion injury through modulation of Akt/GSK-3β/Nrf2 pathway

Tumor necrosis factor α-induced protein 1 (TNFAIP1) has been documented as a vital regulator of apoptosis and oxidative stress under various pathological conditions. However, whether TNFAIP1 plays a role in myocardial ischemia/reperfusion (I/R) injury has not been well investigated. This work aimed to evaluate the possible role of TNFAIP1 in mediating myocardial I/R injury. Firstly, we demonstrated that TNFAIP1 expression was dramatically increased in rat cardiomyocytes following hypoxia/reoxygenation (H/R) in vitro, and in rat myocardial tissues following I/R treatment in vivo. Silencing of TNFAIP1 alleviated H/R-induced apoptosis, oxidative stress and inflammatory response in rat cardiomyocytes in vitro. Moreover, knockdown of TNFAIP1 ameliorated I/R-induced myocardial injury, infarction size, cardiac apoptosis, oxidative stress and inflammatory response in vivo. Further investigation elucidated that knockdown of TNFAIP1 enhanced the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling associated with modulation of the Akt/glycogen synthase kinase-3β (GSK-3β) pathway in vitro and in vivo. Inhibition of Akt markedly abrogated TNFAIP1-knockdown-mediated Nrf2 activation in cardiomyocytes following H/R injury. In addition, suppression of Nrf2 significantly diminished TNFAIP1-knockdown-induced cardioprotective effects in H/R-exposed cardiomyocytes. In summary, this work elucidates that inhibition of TNFAIP1 ameliorates myocardial I/R injury by potentiating Nrf2 signaling via the modulation of the Akt/GSK-3β pathway. Our study highlights a vital role of the TNFAIP1/Akt/GSK-3β/Nrf2 pathway in mediating myocardial I/R injury and suggests TNFAIP1 as an attractive target for treatment of this disease.

Dual-specificity Phosphatase 9 protects against Cardiac Hypertrophy by targeting ASK1

The functions of dual-specificity phosphatase 9 (DUSP9) in hepatic steatosis and metabolic disturbance during nonalcoholic fatty liver disease were discussed in our prior study. However, its roles in the pathophysiology of pressure overload-induced cardiac hypertrophy remain to be illustrated. This study attempted to uncover the potential contributions and underpinning mechanisms of DUSP9 in cardiac hypertrophy. Utilizing the gain-and-loss-of-functional approaches of DUSP9 the cardiac phenotypes arising from the pathological, echocardiographic, and molecular analysis were quantified. The results showed increased levels of DUSP9 in hypertrophic mice heart and angiotensin II treated cardiomyocytes. In accordance with the results of cellular hypertrophy in response to angiotensin II, cardiac hypertrophy exaggeration, fibrosis, and malfunction triggered by pressure overload was evident in the case of cardiac-specific conditional knockout of DUSP9. In contrast, transgenic mice hearts with DUSP9 overexpression portrayed restoration of the hypertrophic phenotypes. Further explorations of molecular mechanisms indicated the direct interaction of DUSP9 with ASK1, which further repressed p38 and JNK signaling pathways. Moreover, blocking ASK1 with ASK1-specific inhibitor compensated the pro-hypertrophic effects induced by DUSP9 deficiency in cardiomyocytes. The main findings of this study suggest the potential of DUSP9 in alleviating cardiac hypertrophy at least partially by repressing ASK1, thereby looks promising as a prospective target against cardiac hypertrophy.

Qindan Capsule Attenuates Myocardial Hypertrophy and Fibrosis in Pressure Overload-Induced Mice Involving mTOR and TGF-β1/Smad Signaling Pathway Inhibition

Qindan capsule (QC), a traditional Chinese medicine compound, has been used to treat hypertension in the clinic for over 30 years. It is still not known about the effects of QC on pressure overload-induced cardiac remodeling. Hence, this study aims to investigate the effects of QC on pressure overload-induced cardiac hypertrophy, fibrosis, and heart failure in mice and to determine the possible mechanisms. Transverse aortic constriction (TAC) surgery was used to induce cardiac hypertrophy and heart failure in C57BL/6 mice. Mice were treated with QC or losartan for 8 weeks after TAC surgery. Cardiac function indexes were evaluated with transthoracic echocardiography. Cardiac pathology was detected using HE and Masson's trichrome staining. Cardiomyocyte ultrastructure was detected using transmission electron microscopy. Hypertrophy-related fetal gene expression was investigated using real-time RT-PCR. The expression of 8-OHdG and the concentration of MDA and Ang-II were assessed by immunohistochemistry stain and ELISA assay, respectively. The total and phosphorylated protein levels of mTOR, p70S6K, 4EBP1, Smad2, and Smad3 and the expression of TGF-β1 and collagen I were measured using western blot. The results showed that low- and high-dose QC improved pressure overload-induced cardiac hypertrophy, fibrosis, and dysfunction. QC inhibited ANP, BNP, and β-MHC mRNA expression in failing hearts. QC improved myocardial ultrastructure after TAC surgery. Furthermore, QC downregulated the expression of 8-OHdG and the concentration of MDA, 15-F_2t-IsoP, and Ang-II in heart tissues after TAC surgery. We also found that QC inhibited the phosphorylation of mTOR, p70S6K, and 4EBP1 and the expression of TGF-β1, p-Smad2, p-Smad3, and collagen I in pressure overload-induced failing hearts. These data indicate that QC has direct benefic effects on pressure overload-induced cardiac hypertrophy, fibrosis, and dysfunction. The protective effects of QC involve prevention of increased oxidative stress injury and Ang-II levels and inhibition of mTOR and TGF-β1/Smad pathways in failing hearts.

PHLDA3 inhibition attenuates endoplasmic reticulum stress-induced apoptosis in myocardial hypoxia/reoxygenation injury by activating the PI3K/AKT signaling pathway

Endoplasmic reticulum stress (ERS)-induced apoptosis serves a crucial role in the pathogenesis of myocardial ischemia/reperfusion injury (MIRI). Previous studies have confirmed that pleckstrin homology-like domain family A member 3 (PHLDA3) is an important mediator in ERS-associated apoptosis. The aim of the current study focused on whether PHLDA3 served protective effects on hypoxia/reoxygenation (H/R)-injured cardiomyocytes by inhibiting ERS-induced apoptosis. Furthermore, the molecular mechanisms associated with the PI3K/AKT signaling pathway were investigated. Primary neonatal rat cardiomyocytes were isolated and randomized into four groups: i) Control + adenovirus encoding scrambled short hairpin RNA (AdshRNA); ii) control + adenoviral vectors encoding PHLDA3 shRNA (AdshPHLDA3); iii) H/R+ AdshRNA and iv) H/R+AdshPHLDA3. AdshPHLDA3 was used to knock down PHLDA3. An H/R injury model was constructed by treatment with hypoxia for 4 h followed by reoxygenation for 6 h. A PI3K/AKT inhibitor, LY294002, was supplemented in mechanistic studies. Cell viability and LDH/CK releases were detected to evaluate myocardial damage. Flow cytometry assays were used to assess apoptotic response. Western blotting assays were used to detect protein expression. The results demonstrated that H/R induced myocardial damage and increased PHLDA3 expression. ERS-induced apoptosis was significantly increased following H/R injury, as indicated by increased apoptotic rates and ERS-associated protein expression, including those of CHOP, 78 kDa glucose-regulated protein and caspase-12. However, PHLDA3 inhibition following AdshPHLDA3 transfection reversed cell damage and ERS-associated apoptosis on H/R injury. Studies for molecular mechanisms concluded that the apoptosis-inhibition effects and cardioprotective roles of PHLDA3 inhibition were induced partly by the activation of the PI3K/AKT pathway, which was verified by LY294002 treatment. In conclusion, in the process of H/R injury, PHLDA3 inhibition reduced ERS-induced apoptosis and H/R injury by activating the PI3K/AKT pathway. PHLDA3 may be a therapeutic target for the treatment of MIRI.

Inhibition of microRNA-146a attenuated heart failure in myocardial infarction rats

The aim of the present study was to determine the roles of microRNA (miR)-146a on myocardial infarction (MI)-induced heart failure and cardiac remodeling. Experiments were carried out in Sprague-Dawley rats treated with ligation of left coronary artery to induce heart failure, and in primary neonatal rat cardiac fibroblasts (CFs) and cardiomyocytes treated with angiotensin (Ang) II. Four weeks after MI, rats were injected with miR-146a antagomiR or agomiR via tail vein. After 2 weeks of injection, the rats were killed. In MI rats, left ventricle (LV) ejection fraction and fractional shortening were reduced, and LV volumes in diastole and systole were increased, which were reversed by miR-146a antagomiR, and further exacerbated after miR-146a agomiR treatment. Administration of miR-146a antagomiR improved the decreases of LV ±dp/dt_max and LV systolic pressure (LVSP), and the increase in LV end-diastolic pressure (LVEDP) of MI rats, but miR-146a agomiR deteriorated the LV ±dp/dt_max, LVSP and LVEDP. The increases in the levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), collagen I and collagen III in the heart, and ST2 and norepinephrine in the serum of MI rats were inhibited by miR-146a antagomiR, but aggravated after miR-146a agomiR treatment. The increases of collagen I and collagen III levels induced by Ang II in CFs, and the increases of ANP and BNP levels induced by Ang II in cardiomyocytes were inhibited by miR-146a antagomiR, but aggravated by miR-146a agomiR. These results demonstrated that inhibition of miR-146a improved cardiac dysfunction and cardiac remodeling in heart failure rats.

Novel Role for Pleckstrin Homology-Like Domain Family A, Member 3 in the Regulation of Pathological Cardiac Hypertrophy

Background Pleckstrin homology-like domain family A, member 3 (PHLDA3), a crucial member of the PHLDA family, is involved in tumor suppression, kidney injury, liver injury, and glucose metabolism. However, the role of PHLDA3 in pathological cardiac hypertrophy and heart failure remains unclear. Methods and Results In the present study, PHLDA3 expression was downregulated in hypertrophic murine hearts and angiotensin II-treated cardiomyocytes. Next, an in vitro study suggested, by using gain- and loss-of-function approaches, that PHLDA3 attenuates Ang II exposure-induced cardiomyocyte hypertrophy. Consistent with the cell phenotype, disruption of PHLDA3 aggravated the effects of pressure overload-induced pathological cardiac hypertrophy, fibrosis, and dysfunction. In contrast, PHLDA3 overexpression resulted in an attenuated hypertrophic phenotype. Molecular analysis revealed that PHLDA3 suppressed the activation of AKT-mTOR-GSK3β-P70S6K signaling in response to hypertrophic stress, and the blockage of AKT activation rescued these adverse pathological effects of PHLDA3 deficiency-induced by AB and Ang II, respectively, in vivo and in vitro. Conclusions Collectively, our data indicated that PHLDA3 could ameliorate pressure overload-induced cardiac remodeling mainly by blocking the AKT signaling pathway, suggesting that PHLDA3 may represent a therapeutic target for the treatment of pathological cardiac hypertrophy and heart failure.