Downregulation of P300/CBP-Associated Factor Attenuates Myocardial Ischemia-Reperfusion Injury Via Inhibiting Autophagy

Aerobic training attenuates cardiac remodeling in mice post-myocardial infarction by inhibiting the p300/CBP-associated factor

Aerobic training (AT), an effective form of cardiac rehabilitation, has been shown to be beneficial for cardiac repair and remodeling after myocardial infarction (MI). The p300/CBP-associated factor (PCAF) is one of the most important lysine acetyltransferases and is involved in various biological processes. However, the role of PCAF in AT and AT-mediated cardiac remodeling post-MI has not been determined. Here, we found that the PCAF protein level was significantly increased after MI, while AT blocked the increase in PCAF. AT markedly improved cardiac remodeling in mice after MI by reducing endoplasmic reticulum stress (ERS). In vivo, similar to AT, pharmacological inhibition of PCAF by Embelin improved cardiac recovery and attenuated ERS in MI mice. Furthermore, we observed that both IGF-1, a simulated exercise environment, and Embelin protected from H2O2-induced cardiomyocyte injury, while PCAF overexpression by viruses or the sirtuin inhibitor nicotinamide eliminated the protective effect of IGF-1 in H9C2 cells. Thus, our data indicate that maintaining low PCAF levels plays an essential role in AT-mediated cardiac protection, and PCAF inhibition represents a promising therapeutic target for attenuating cardiac remodeling after MI.

Oxidized DJ-1 activates the p-IKK/NF-κB/Beclin1 pathway by binding PTEN to induce autophagy and exacerbate myocardial ischemia-reperfusion injury

Patients with myocardial infarction have a much worse prognosis when they have myocardial ischemia-reperfusion (I/R) injury. Further research into the molecular basis of myocardial I/R injury is therefore urgently needed, as well as the identification of novel therapeutic targets and linkages to interventions. Three cysteine residues are present in DJ-1 at amino acids 46, 53, and 106 sites, with the cysteine at position 106 being the most oxidation-prone. This study sought to understand how oxidized DJ-1(C106) contributes to myocardial I/R damage. Rats' left anterior descending branches were tied off to establish a myocardial I/R model in vivo. A myocardial I/R model in vitro was established via anoxia/reoxygenation (A/R) of H9c2 cells. The results showed that autophagy increased after I/R, accompanied by the increased expression of oxidized DJ-1 (ox-DJ-1). In contrast, after pretreatment with NAC (N-acetylcysteine, a ROS scavenger) or Comp-23 (Compound-23, a specific antioxidant binding to the C106 site of DJ-1), the levels of ox-DJ-1, autophagy and LDH release decreased, and cell survival rate increased. Furthermore, the inhibition of interaction between ox-DJ-1 and PTEN could increase PTEN phosphatase activity, inhibit the p-IKK/NF-κB/Beclin1 pathway, reduce injurious autophagy, and alleviate A/R injury. However, BA (Betulinic acid, a NF-κB agonist) was able to reverse the protective effects produced by Comp-23 pretreatment. In conclusion, ox-DJ-1 could activate detrimental autophagy through the PTEN/p-IKK/NF-κB/Beclin1 pathway and exacerbate myocardial I/R injury.

Role of transcriptional cofactors in cardiovascular diseases

Cardiovascular disease is a main cause of mortality in the world and the highest incidence of all diseases. However, the mechanism of the pathogenesis of cardiovascular disease is still unclear, and we need to continue to explore its mechanism of action. The occurrence and development of cardiovascular disease is significantly associated with genetic abnormalities, and gene expression is affected by transcriptional regulation. In this complex process, the protein-protein interaction promotes the RNA polymerase II to the initiation site. And in this process of transcriptional regulation, transcriptional cofactors are responsible for passing cues from enhancers to promoters and promoting the binding of RNA polymerases to promoters, so transcription cofactors playing a key role in gene expression regulation. There is growing evidence that transcriptional cofactors play a critical role in cardiovascular disease. Transcriptional cofactors can promote or inhibit transcription by affecting the function of transcription factors. It can affect the initiation and elongation process of transcription by forming complexes with transcription factors, which are important for the stabilization of DNA rings. It can also act as a protein that interacts with other proteins to affect the expression of other genes. Therefore, the aim of this overview is to summarize the effect of some transcriptional cofactors such as BRD4, EP300, MED1, EZH2, YAP, SIRT6 in cardiovascular disease and to provide a promising therapeutic strategy for the treatment of cardiovascular disease.

Ginsenoside Rb2 inhibits p300-mediated SF3A2 acetylation at lysine 10 to promote Fscn1 alternative splicing against myocardial ischemic/reperfusion injury

INTRODUCTION

Ginsenosides (GS) derived from Panax ginseng can regulate protein acetylation to promote mitochondrial function for protecting cardiomyocytes. However, the potential mechanisms of GS for regulating acetylation modification are not yet clear.

OBJECTIVES

This study aimed to explore the potential mechanisms of GS in regulating protein acetylation and identify ginsenoside monomer for fighting myocardial ischemia-related diseases.

METHODS

The 4D-lable free acetylomic analysis was employed to gain the acetylated proteins regulated by GS pretreatment. The co-immunoprecipitation assay, immunofluorescent staining, and mitochondrial respiration measurement were performed to detect the effect of GS or ginsenoside monomer on acetylated protein level and mitochondrial function. RNA sequencing, site-specific mutation, and shRNA interference were used to explore the downstream targets of acetylation modificationby GS. Cellular thermal shift assay and surface plasmon resonance were used for identifying the binding of ginsenoside with target protein.

RESULTS

In the cardiomyocytes of normal, oxygen glucose deprivation and/or reperfusion conditions, the acetylomic analysis identified that the acetylated levels of spliceosome proteins were inhibited by GS pretreatment and SF3A2 acetylation at lysine 10 (K10) was significantly decreased as a potential target of GS. Ginsenoside Rb2 was identified as one of the active ginsenoside monomers for reducing the acetylation of SF3A2 (K10), which enhanced mitochondrial respiration against myocardial ischemic injury in in vivo and in vitro experiments. RNA-seq analysis showed that ginsenoside Rb2 promoted alternative splicing of mitochondrial function-related genes and the level of fascin actin-bundling protein 1 (Fscn1) was obviously upregulated, which was dependent on SF3A2 acetylation. Critically, thermodynamic, kinetic and enzymatic experiments demonstrated that ginsenoside Rb2 directly interacted with p300 for inhibiting its activity.

CONCLUSION

These findings provide a novel mechanism underlying cardiomyocyte protection of ginsenoside Rb2 by inhibiting p300-mediated SF3A2 acteylation for promoting Fscn1 expression, which might be a promising approach for the prevention and treatment of myocardial ischemic diseases.

The participation of non-canonical autophagic proteins in the autophagy process and their potential as therapeutic targets

INTRODUCTION

Autophagy is a conserved catabolic process that helps recycle intracellular components to maintain homeostasis. The completion of autophagy requires the synergistic effect of multiple canonical autophagic proteins. Defects in autophagy machinery have been reported to promote diseases, rendering autophagy a bone fide health-modifying agent. However, the clinical implication of canonical pan-autophagic activators or inhibitors has often led to undesirable side effects, making it urgent to find a safer autophagy-related therapeutic target. The discovery of non-canonical autophagic proteins has been found to specifically affect the development of diseases without causing a universal impact on autophagy and has shed light on finding a safer way to utilize autophagy in the therapeutic context.

AREAS COVERED

This review summarizes recently discovered non-canonical autophagic proteins, how these proteins influence autophagy, and their potential therapeutic role in the disease due to their interaction with autophagy.

EXPERT OPINION

Several therapies have been studied thus far and continued research is needed to identify the potential that non-canonical autophagic proteins have for treating certain diseases. In the meantime, continue to uncover new non-canonical autophagic proteins and examine which are likely to have therapeutic implications.

Downregulation of P300/CBP-Associated Factor Protects from Vascular Aging via Nrf2 Signal Pathway Activation

Increasing evidence has shown that vascular aging has a key role in the pathogenesis of vascular diseases. P300/CBP-associated factor (PCAF) is involved in many vascular pathological processes, but the role of PCAF in vascular aging is unknown. This study aims to explore the role and underlying mechanism of PCAF in vascular aging. The results demonstrated that the expression of PCAF was associated with age and aging, and remarkably increased expression of PCAF was present in human atherosclerotic coronary artery. Downregulation of PCAF could reduce angiotensin II (AngII)-induced senescence of rat aortic endothelial cells (ECs) in vitro. In addition, inhibition of PCAF with garcinol alleviated AngII-induced vascular senescence phenotype in mice. Downregulation of PCAF could alleviate AngII-induced oxidative stress injury in ECs and vascular tissue. Moreover, PCAF and nuclear factor erythroid-2-related factor 2 (Nrf2) could interact directly, and downregulation of PCAF alleviated vascular aging by promoting the activation of Nrf2 and enhancing the expression of its downstream anti-aging factors. The silencing of Nrf2 with small interfering RNA attenuated the protective effect of PCAF downregulation from vascular aging. These findings indicate that downregulation of PCAF alleviates oxidative stress by activating the Nrf2 signaling pathway and ultimately inhibits vascular aging. Thus, PCAF may be a promising target for aging-related cardiovascular disease.

Astaxanthin Inhibits Matrix Metalloproteinase Expression by Suppressing PI3K/AKT/mTOR Activation in Helicobacter pylori-Infected Gastric Epithelial Cells

Helicobacter pylori (H. pylori) increases production of reactive oxygen species (ROS) and activates signaling pathways associated with gastric cell invasion, which are mediated by matrix metalloproteinases (MMPs). We previously demonstrated that H. pylori activated mitogen-activated protein kinase (MAPK) and increased expression of MMP-10 in gastric epithelial cells. MMPs degrade the extracellular matrix, enhancing tumor invasion and cancer progression. The signaling pathway of phosphatidylinositol 3-kinase (PI3K)/serine/threonine protein kinase B (AKT)/mammalian target of rapamycin (mTOR) is associated with MMP expression. ROS activates PIK3/AKT/mTOR signaling in cancer. Astaxanthin, a xanthophyll carotenoid, shows antioxidant activity by reducing ROS levels in gastric epithelial cells infected with H. pylori. This study aimed to determine whether astaxanthin inhibits MMP expression, cell invasion, and migration by reducing the PI3K/AKT/mTOR signaling in H. pylori-infected gastric epithelial AGS cells. H. pylori induced PIK3/AKT/mTOR and NF-κB activation, decreased IκBα, and induced MMP (MMP-7 and -10) expression, the invasive phenotype, and migration in AGS cells. Astaxanthin suppressed these H. pylori-induced alterations in AGS cells. Specific inhibitors of PI3K, AKT, and mTOR reversed the H. pylori-stimulated NF-κB activation and decreased IκBα levels in the cells. In conclusion, astaxanthin suppressed MMP expression, cell invasion, and migration via inhibition of PI3K/AKT/mTOR/NF-κB signaling in H. pylori-stimulated gastric epithelial AGS cells.

Cardiac Acetylation in Metabolic Diseases

Lysine acetylation is a highly conserved mechanism that affects several biological processes such as cell growth, metabolism, enzymatic activity, subcellular localization of proteins, gene transcription or chromatin structure. This post-translational modification, mainly regulated by lysine acetyltransferase (KAT) and lysine deacetylase (KDAC) enzymes, can occur on histone or non-histone proteins. Several studies have demonstrated that dysregulated acetylation is involved in cardiac dysfunction, associated with metabolic disorder or heart failure. Since the prevalence of obesity, type 2 diabetes or heart failure rises and represents a major cause of cardiovascular morbidity and mortality worldwide, cardiac acetylation may constitute a crucial pathway that could contribute to disease development. In this review, we summarize the mechanisms involved in the regulation of cardiac acetylation and its roles in physiological conditions. In addition, we highlight the effects of cardiac acetylation in physiopathology, with a focus on obesity, type 2 diabetes and heart failure. This review sheds light on the major role of acetylation in cardiovascular diseases and emphasizes KATs and KDACs as potential therapeutic targets for heart failure.

Physalin B inhibits PDGF-BB-induced VSMC proliferation, migration and phenotypic transformation by activating the Nrf2 pathway

Vascular intimal hyperplasia is a hallmark event in vascular restenosis. The excessive proliferation, migration and phenotypic transformation of vascular smooth muscle cells (VSMCs) play important roles in the pathological mechanism of vascular intimal hyperplasia. Physalin B is an alcoholate isolated from Physalis (Solanaceae) that has a wide range of biological activities. However, the effect of physalin B on VSMCs is currently unclear. In this study, we demonstrated that physalin B significantly inhibited the proliferation, migration and phenotypic transformation of VSMCs induced by PDGF-BB. Physalin B also reduced inflammation and oxidative stress in VSMCs induced by PDGF-BB. Mechanistic studies showed that physalin B plays a role mainly by activating Nrf2. After Nrf2 activation, physalin B mitigates oxidative stress by enhancing the expression of the antioxidant gene HO-1; on the other hand, physalin B inhibits the NF-κB pathway to alleviate the inflammatory response. These two effects ultimately reduce the proliferation, migration and phenotypic transformation of VSMCs induced by PDGF-BB. In addition, in the mouse carotid artery ligation model, physalin B prevented intimal hyperplasia and inhibited the proliferation, migration and phenotypic transformation of cells in the hyperplastic intima. In conclusion, we provided significant evidence that physalin B abrogates PDGF-BB-induced VSMC proliferation, migration, phenotypic transformation and intimal hyperplasia by activating Nrf2-mediated signal transduction. Therefore, physalin B may be a potential therapeutic agent for preventing or treating restenosis.

Downregulation of p300/CBP-associated factor inhibits cardiomyocyte apoptosis via suppression of NF-κB pathway in ischaemia/reperfusion injury rats

Cardiomyocyte apoptosis is the main reason of cardiac injury after myocardial ischaemia-reperfusion (I/R) injury (MIRI), but the role of p300/CBP-associated factor (PCAF) on myocardial apoptosis in MIRI is unknown. The aim of this study was to investigate the main mechanism of PCAF modulating cardiomyocyte apoptosis in MIRI. The MIRI model was constructed by ligation of the rat left anterior descending coronary vessel for 30 min and reperfusion for 24 h in vivo. H9c2 cells were harvested after induced by hypoxia for 6 h and then reoxygenation for 24 h (H/R) in vitro. The RNA interference PCAF expression adenovirus was transfected into rat myocardium and H9c2 cells. The area of myocardial infarction, cardiac function, myocardial injury marker levels, apoptosis, inflammation and oxidative stress were detected respectively. Both I/R and H/R remarkably upregulated the expression of PCAF, and downregulation of PCAF significantly attenuated myocardial apoptosis, inflammation and oxidative stress caused by I/R and H/R. In addition, downregulation of PCAF inhibited the activation of NF-κB signalling pathway in cardiomyocytes undergoing H/R. Pretreatment of lipopolysaccharide, a NF-κB pathway activator, could blunt these protective effects of PCAF downregulation on myocardial apoptosis in MIRI. These results highlight that downregulation of PCAF could reduce cardiomyocyte apoptosis by inhibiting the NF-κB pathway, thereby providing protection for MIRI. Therefore, PCAF might be a promising target for protecting against cardiac dysfunction induced by MIRI.

Function of histone methylation and acetylation modifiers in cardiac hypertrophy

Cardiac hypertrophy is an adaptive response of the heart to increased workload induced by various physiological or pathological stimuli. It is a common pathological process in multiple cardiovascular diseases, and it ultimately leads to heart failure. The development of cardiac hypertrophy is accompanied by gene expression reprogramming, a process that is largely dependent on epigenetic regulation. Histone modifications such as methylation and acetylation are dynamically regulated under cardiac stress. These consequently contribute to the pathogenesis of cardiac hypertrophy via compensatory or maladaptive transcriptome reprogramming. Histone methylation and acetylation modifiers play crucial roles in epigenetic remodeling during the pathogenesis of cardiac hypertrophy. Regulation of histone methylation and acetylation modifiers serves as a bridge between signal transduction and downstream gene reprogramming. Exploring the role of histone modifiers in cardiac hypertrophy provides novel therapeutic strategies to treat cardiac hypertrophy and heart failure. In this review, we summarize the recent advancements in functional histone methylation and acetylation modifiers in cardiac hypertrophy, with an emphasis on the underlying mechanisms and the therapeutic potential.

Acetyl-CoA Metabolism and Histone Acetylation in the Regulation of Aging and Lifespan

Acetyl-CoA is a metabolite at the crossroads of central metabolism and the substrate of histone acetyltransferases regulating gene expression. In many tissues fasting or lifespan extending calorie restriction (CR) decreases glucose-derived metabolic flux through ATP-citrate lyase (ACLY) to reduce cytoplasmic acetyl-CoA levels to decrease activity of the p300 histone acetyltransferase (HAT) stimulating pro-longevity autophagy. Because of this, compounds that decrease cytoplasmic acetyl-CoA have been described as CR mimetics. But few authors have highlighted the potential longevity promoting roles of nuclear acetyl-CoA. For example, increasing nuclear acetyl-CoA levels increases histone acetylation and administration of class I histone deacetylase (HDAC) inhibitors increases longevity through increased histone acetylation. Therefore, increased nuclear acetyl-CoA likely plays an important role in promoting longevity. Although cytoplasmic acetyl-CoA synthetase 2 (ACSS2) promotes aging by decreasing autophagy in some peripheral tissues, increased glial AMPK activity or neuronal differentiation can stimulate ACSS2 nuclear translocation and chromatin association. ACSS2 nuclear translocation can result in increased activity of CREB binding protein (CBP), p300/CBP-associated factor (PCAF), and other HATs to increase histone acetylation on the promoter of neuroprotective genes including transcription factor EB (TFEB) target genes resulting in increased lysosomal biogenesis and autophagy. Much of what is known regarding acetyl-CoA metabolism and aging has come from pioneering studies with yeast, fruit flies, and nematodes. These studies have identified evolutionary conserved roles for histone acetylation in promoting longevity. Future studies should focus on the role of nuclear acetyl-CoA and histone acetylation in the control of hypothalamic inflammation, an important driver of organismal aging.