HDAC4 regulates vascular inflammation via activation of autophagy

Targeting histone deacetylase in cardiac diseases

Histone deacetylases (HDAC) catalyze the removal of acetylation modifications on histones and non-histone proteins, which regulates gene expression and other cellular processes. HDAC inhibitors (HDACi), approved anti-cancer agents, emerge as a potential new therapy for heart diseases. Cardioprotective effects of HDACi are observed in many preclinical animal models of heart diseases. Genetic mouse models have been developed to understand the role of each HDAC in cardiac functions. Some of the findings are controversial. Here, we provide an overview of how HDACi and HDAC impact cardiac functions under physiological or pathological conditions. We focus on in vivo studies of zinc-dependent classical HDACs, emphasizing disease conditions involving cardiac hypertrophy, myocardial infarction (MI), ischemic reperfusion (I/R) injury, and heart failure. In particular, we review how non-biased omics studies can help our understanding of the mechanisms underlying the cardiac effects of HDACi and HDAC.

The Role of Autophagy in Vascular Endothelial Cell Health and Physiology

Autophagy is a highly conserved cellular recycling process which enables eukaryotes to maintain both cellular and overall homeostasis through the catabolic breakdown of intracellular components or the selective degradation of damaged organelles. In recent years, the importance of autophagy in vascular endothelial cells (ECs) has been increasingly recognized, and numerous studies have linked the dysregulation of autophagy to the development of endothelial dysfunction and vascular disease. Here, we provide an overview of the molecular mechanisms underlying autophagy in ECs and our current understanding of the roles of autophagy in vascular biology and review the implications of dysregulated autophagy for vascular disease. Finally, we summarize the current state of the research on compounds to modulate autophagy in ECs and identify challenges for their translation into clinical use.

Berberine ameliorates contrast-induced acute kidney injury by regulating HDAC4-FoxO3a axis-induced autophagy: In vivo and in vitro

In hospitals, contrast-induced acute kidney injury (CI-AKI) is a major cause of renal failure. This study evaluates berberine's (BBR) renal protection and its potential HDAC4 mechanism. CI-AKI in rats was induced with 10 mL kg-1 ioversol. Rats were divided into five groups: Ctrl, BBR, CI-AKI, CI-AKI + BBR, and CI-AKI + Tasq. The renal function of CI-AKI rats was determined by measuring serum creatinine and blood urea nitrogen. Histopathological changes and apoptosis of renal tubular epithelial cells were observed by HE and terminal deoxynucleotidyl transferase (TdTase)-mediated dUTP-biotin nick end labeling (TUNEL) staining. Transmission electron microscopy was used to observe autophagic structures. In vitro, a CI-AKI cell model was created with ioversol-treated HK-2 cells. Treatments included BBR, Rapa, HCQ, and Tasq. Analyses focused on proteins and genes associated with kidney injury, apoptosis, autophagy, and the HDAC4-FoxO3a axis. BBR showed significant protective effects against CI-AKI both in vivo and in vitro. It inhibited apoptosis by increasing Bcl-2 protein levels and decreasing Bax levels. BBR also activated autophagy, as indicated by changes in autophagy-related proteins and autophagic flux. The study further revealed that the contrast agent ioversol increased the expression of HDAC4, which led to elevated levels of phosphorylated FoxO3a (p-FoxO3a) and acetylated FoxO3a (Ac-FoxO3a). However, BBR inhibited HDAC4 expression, resulting in decreased levels of p-FoxO3a and Ac-FoxO3a. This activation of autophagy-related genes, regulated by the transcription factor FoxO3a, played a role in BBR's protective effects. BBR, a traditional Chinese medicine, shows promise against CI-AKI. It may counteract CI-AKI by modulating HDAC4 and FoxO3a, enhancing autophagy, and limiting apoptosis.

Epigenetically regulated inflammation in vascular senescence and renal progression of chronic kidney disease

Chronic kidney disease (CKD) and its complications, including vascular senescence and progressive renal fibrosis, are associated with inflammation. Vascular senescence, in particular, has emerged as an instrumental mediator of vascular inflammation that potentially worsens renal function. Epigenetically regulated inflammation involving histone modification, DNA methylation, actions of microRNAs and other non-coding RNAs, and their reciprocal reactions during vascular senescence and inflammaging are underappreciated. Their synergistic effects can contribute to CKD progression. Vascular senotherapeutics or pharmacological anti-senescent therapies based on epigenetic machineries can therefore be plausible options for ameliorating vascular aging and even halting the worsening of renal fibrosis. These include histone deacetylase modulators, histone methyltransferase modulators, other histone modification effectors, DNA methyltransferase inhibitors, telomerase reverse transcriptase enhancers, microRNA mimic delivery, and small molecules with microRNA-regulating potentials. Some of these molecules have already been tested and have shown anecdotal evidence for treating uremic vasculopathy and renal fibrosis, supporting the feasibility of this approach.

Zinc-Dependent Histone Deacetylases in Lung Endothelial Pathobiology

A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and, as such, provides a semi-selective barrier between the blood and the interstitial space. Compromise of the lung EC barrier due to inflammatory or toxic events may result in pulmonary edema, which is a cardinal feature of acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS). The EC functions are controlled, at least in part, via epigenetic mechanisms mediated by histone deacetylases (HDACs). Zinc-dependent HDACs represent the largest group of HDACs and are activated by Zn2+. Members of this HDAC group are involved in epigenetic regulation primarily by modifying the structure of chromatin upon removal of acetyl groups from histones. In addition, they can deacetylate many non-histone histone proteins, including those located in extranuclear compartments. Recently, the therapeutic potential of inhibiting zinc-dependent HDACs for EC barrier preservation has gained momentum. However, the role of specific HDAC subtypes in EC barrier regulation remains largely unknown. This review aims to provide an update on the role of zinc-dependent HDACs in endothelial dysfunction and its related diseases. We will broadly focus on biological contributions, signaling pathways and transcriptional roles of HDACs in endothelial pathobiology associated mainly with lung diseases, and we will discuss the potential of their inhibitors for lung injury prevention.

ZIP4 upregulation aggravates nucleus pulposus cell degradation by promoting inflammation and oxidative stress by mediating the HDAC4-FoxO3a axis

BACKGROUND

Extracellular matrix metabolism dysregulation in nucleus pulposus (NP) cells represents a crucial pathophysiological feature of intervertebral disc degeneration (IDD). Our study elucidates the role and mechanism of Testis expressed 11 (TEX11, also called ZIP4) extracellular matrix degradation in the NP.

MATERIALS AND METHODS

Interleukin-1β (IL-1β) and H2O2 were used to treat NP cells to establish an IDD cell model. Normal NP tissues and NP tissues from IDD patients were harvested. ZIP4 mRNA and protein profiles in NP cells and tissues were examined. Enzyme-linked immunosorbent assay (ELISA) confirmed the profiles of TNF-α, IL-6, MDA, and SOD in NP cells. The alterations of reactive oxygen species (ROS), lactate dehydrogenase (LDH), COX2, iNOS, MMP-3, MMP-13, collagen II, aggrecan, FoxO3a, histone deacetylase 4 (HDAC4), Sirt1 and NF-κB levels in NP cells were determined using different assays.

RESULTS

The ZIP4 profile increased in the NP tissues of IDD patients and IL-1β- or H2O2-treated NP cells. ZIP4 upregulation bolstered inflammation and oxidative stress in NP cells undergoing IL-1β treatment and exacerbated their extracellular matrix degradation, whereas ZIP4 knockdown produced the opposite outcome. Mechanistically, ZIP4 upregulated HDAC4 and enhanced NF-κB phosphorylation while repressing Sirt1 and FoxO3a phosphorylation levels. HDAC4 knockdown or Sirt1 promotion attenuated the effects mediated by ZIP4 overexpression in NP cells.

CONCLUSIONS

ZIP4 upregulation aggravates the extracellular matrix (ECM) degradation of NP cells by mediating inflammation and oxidative stress through the HDAC4-FoxO3a axis.

IL-17A is involved in the hyperplasia of blood vessels in local lesions of psoriasis by inhibiting autophagy

OBJECTIVE

Increased angiogenesis is a pathological feature of psoriasis, but the pathomechanisms of angiogenesis in psoriasis are not clear. Interleukin-17A (IL-17A) is the major effect factor in the pathogenesis of psoriasis. Our results showed that IL-17A can promote angiogenesis and cause endothelial cell inflammation. Autophagy plays an important role not only in regulating inflammation, but also in regulating angiogenesis. Whether angiogenesis in psoriasis is related to autophagy remains unclear. In this study, we treated human umbilical vein endothelial cells (HUVECs) with IL-17A to simulate increased angiogenesis to study whether increased angiogenesis in psoriasis is related to autophagy.

METHODS AND RESULTS

Our results showed that treatment of HUVECs with IL-17A significantly increased angiogenesis and expression levels of mRNA for multiple proinflammatory cytokines (CCL20, IL-8, CCL2, IL-6, and IL-1β) and, while decreasing intracellular levels of nitric oxide (NO) and NO synthase (NOS) activity. Moreover, IL-17A inhibited autophagy as shown that IL-17A significantly increased expression levels of LC3II and p62 proteins. Induction of autophagy ameliorated IL-17A-mediated inflammatory response and inhibited angiogenesis, accompanied by increased p-AMPKα(Thr172) and p-ULK1(Ser555) expression, and decreased p-mTOR(Ser2448) and p-ULK1(Ser757) expression. Furthermore, inhibition of either AMPK or lysosomal acidification completely overrode autophagy-induced changes in angiogenesis and NOS activity. Finally, induction of autophagy decreased apoptosis and caspase-3 activity in IL-17A-treated HUVECs.

CONCLUSIONS

These results showed that IL-17A is involved in angiogenesis and inflammatory response by inhibiting autophagy through AMPK signaling pathway, suggesting that autophagy may be a new therapeutic target for psoriasis.

Serum histone deacetylase 4 longitudinal change for estimating major adverse cardiovascular events in acute coronary syndrome patients receiving percutaneous coronary intervention

OBJECTIVE

Histone deacetylase 4 (HDAC4) regulates lipid accumulation, inflammation, endothelial injury, and atherosclerosis to participate in the pathogenesis of cardiovascular diseases. This study aimed to explore the value of serum HDAC4 change before and after percutaneous coronary intervention (PCI) in predicting major adverse cardiovascular events (MACE) risk in acute coronary syndrome (ACS) patients.

METHODS

HDAC4 from serum was detected by enzyme-linked immunosorbent assay in 340 ACS patients at baseline, day (D)1, D3, and D7 after PCI, and from 30 healthy controls (HCs). MACE was recorded during follow-up.

RESULTS

HDAC4 was decreased in ACS patients versus HCs (P < 0.001). In ACS patients, HDAC4 was negatively related to total cholesterol (P = 0.025), low-density lipoprotein cholesterol (P = 0.007), C-reactive protein (P < 0.001), cardiac troponin I (P < 0.001), and hyperlipidemia history (P = 0.015). Additionally, HDAC4 was lowest in ST-elevation myocardial infarction (STEMI) patients, followed by non-STEMI patients, and highest in unstable angina patients (P = 0.010). After PCI, HDAC4 was decreased from baseline to D1, then increased until D7 (P < 0.001). Furthermore, HDAC4 at baseline (P = 0.002), D1 (P < 0.001), D3 (P < 0.001), and D7 (P < 0.001) were all reduced in patients who experienced MACE versus those who did not. Meanwhile, high HDAC4 at baseline (P = 0.036), D1 (P = 0.010), D3 (P = 0.012), and D7 (P = 0.012) estimated decreased accumulating MACE risk by Kaplan-Meier curve. Multivariate logistic analysis revealed that HDAC4 at D1 was independently linked to lower MACE risk (odds ratio = 0.957, P = 0.039).

CONCLUSION

Serum HDAC4 is decreased from baseline to D1, then elevated until D7, and its increased level correlates with lower MACE risk in ACS patients receiving PCI.

Age and vascular aging: an unexplored frontier

Vascular age is an emerging field in cardiovascular risk assessment. This concept includes multifactorial changes in the arterial wall, with arterial stiffness as its most relevant manifestation, leading to increased arterial pressure and pulsatile flow in the organs. Today, the approved test for measuring vascular age is pulse wave velocity, which has been proven to predict cardiovascular events. Furthermore, vascular phenotypes, such as early vascular aging and "SUPERNOVA," representing phenotypic extremes of vascular aging, have been found. The identification of these phenotypes opens a new field of study in cardiovascular physiology. Lifestyle interventions and pharmacological therapy have positively affected vascular health, reducing arterial stiffness. This review aims to define the concepts related to vascular age, pathophysiology, measurement methods, clinical signs and symptoms, and treatment.

Acetylation in pathogenesis: Revealing emerging mechanisms and therapeutic prospects

Protein acetylation modifications play a central and pivotal role in a myriad of biological processes, spanning cellular metabolism, proliferation, differentiation, apoptosis, and beyond, by effectively reshaping protein structure and function. The metabolic state of cells is intricately connected to epigenetic modifications, which in turn influence chromatin status and gene expression patterns. Notably, pathological alterations in protein acetylation modifications are frequently observed in diseases such as metabolic syndrome, cardiovascular disorders, and cancer. Such abnormalities can result in altered protein properties and loss of function, which are closely associated with developing and progressing related diseases. In recent years, the advancement of precision medicine has highlighted the potential value of protein acetylation in disease diagnosis, treatment, and prevention. This review includes provocative and thought-provoking papers outlining recent breakthroughs in acetylation modifications as they relate to cardiovascular disease, mitochondrial metabolic regulation, liver health, neurological health, obesity, diabetes, and cancer. Additionally, it covers the molecular mechanisms and research challenges in understanding the role of acetylation in disease regulation. By summarizing novel targets and prognostic markers for the treatment of related diseases, we aim to contribute to the field. Furthermore, we discuss current hot topics in acetylation research related to health regulation, including N4-acetylcytidine and liquid-liquid phase separation. The primary objective of this review is to provide insights into the functional diversity and underlying mechanisms by which acetylation regulates proteins in disease contexts.

Histone and Histone Acetylation-Related Alterations of Gene Expression in Uninvolved Psoriatic Skin and Their Effects on Cell Proliferation, Differentiation, and Immune Responses

Psoriasis is a chronic immune-mediated skin disease in which the symptom-free, uninvolved skin carries alterations in gene expression, serving as a basis for lesion formation. Histones and histone acetylation-related processes are key regulators of gene expression, controlling cell proliferation and immune responses. Dysregulation of these processes is likely to play an important role in the pathogenesis of psoriasis. To gain a complete overview of these potential alterations, we performed a meta-analysis of a psoriatic uninvolved skin dataset containing differentially expressed transcripts from nearly 300 individuals and screened for histones and histone acetylation-related molecules. We identified altered expression of the replication-dependent histones HIST2H2AA3 and HIST2H4A and the replication-independent histones H2AFY, H2AFZ, and H3F3A/B. Eight histone chaperones were also identified. Among the histone acetyltransferases, ELP3 and KAT5 and members of the ATAC, NSL, and SAGA acetyltransferase complexes are affected in uninvolved skin. Histone deacetylation-related alterations were found to affect eight HDACs and members of the NCOR/SMRT, NURD, SIN3, and SHIP HDAC complexes. In this article, we discuss how histone and histone acetylation-related expression changes may affect proliferation and differentiation, as well as innate, macrophage-mediated, and T cell-mediated pro- and anti-inflammatory responses, which are known to play a central role in the development of psoriasis.

Mechanisms underlying the role of endoplasmic reticulum stress in the placental injury and fetal growth restriction in an ovine gestation model

BACKGROUND

Exposure to bisphenol A (BPA), an environmental pollutant known for its endocrine-disrupting properties, during gestation has been reported to increase the risk of fetal growth restriction (FGR) in an ovine model of pregnancy. We hypothesized that the FGR results from the BPA-induced insufficiency and barrier dysfunction of the placenta, oxidative stress, inflammatory responses, autophagy and endoplasmic reticulum stress (ERS). However, precise mechanisms underlying the BPA-induced placental dysfunction, and subsequently, FGR, as well as the potential involvement of placental ERS in these complications, remain to be investigated.

METHODS

In vivo experiment, 16 twin-pregnant (from d 40 to 130 of gestation) Hu ewes were randomly distributed into two groups (8 ewes each). One group served as a control and received corn oil once a day, whereas the other group received BPA (5 mg/kg/d as a subcutaneous injection). In vitro study, ovine trophoblast cells (OTCs) were exposed to 4 treatments, 6 replicates each. The OTCs were treated with 400 μmol/L BPA, 400 μmol/L BPA + 0.5 μg/mL tunicamycin (Tm; ERS activator), 400 μmol/L BPA + 1 μmol/L 4-phenyl butyric acid (4-PBA; ERS antagonist) and DMEM/F12 complete medium (control), for 24 h.

RESULTS

In vivo experiments, pregnant Hu ewes receiving the BPA from 40 to 130 days of pregnancy experienced a decrease in placental efficiency, progesterone (P4) level and fetal weight, and an increase in placental estrogen (E2) level, together with barrier dysfunctions, OS, inflammatory responses, autophagy and ERS in type A cotyledons. In vitro experiment, the OTCs exposed to BPA for 24 h showed an increase in the E2 level and related protein and gene expressions of autophagy, ERS, pro-apoptosis and inflammatory response, and a decrease in the P4 level and the related protein and gene expressions of antioxidant, anti-apoptosis and barrier function. Moreover, treating the OTCs with Tm aggravated BPA-induced dysfunction of barrier and endocrine (the increased E2 level and decreased P4 level), OS, inflammatory responses, autophagy, and ERS. However, treating the OTCs with 4-PBA reversed the counteracted effects of Tm mentioned above.

CONCLUSIONS

In general, the results reveal that BPA exposure can cause ERS in the ovine placenta and OTCs, and ERS induction might aggravate BPA-induced dysfunction of the placental barrier and endocrine, OS, inflammatory responses, and autophagy. These data offer novel mechanistic insights into whether ERS is involved in BPA-mediated placental dysfunction and fetal development.

LncRNA CASC11 upregulation promotes HDAC4 to alleviate oxidized low-density lipoprotein-induced injury of cardiac microvascular endothelial cells

Long noncoding RNAs (LncRNAs) are essential to regulate the pathogenesis of coronary artery disease (CAD). This study was conducted to analyze the functionality of long noncoding RNA cancer susceptibility candidate 11 (lncRNA CASC11) in oxidized low-density lipoprotein (ox-LDL)-induced injury of cardiac microvascular endothelial cells (CMECs). CMECs were treated with ox-LDL to induce the CAD cell model. The cellular expression levels of CASC11 and histone deacetylase 4 (HDAC4) were determined by real-time quantitative polymerase chain reaction or Western blot assay. Cell absorbance, apoptosis, angiogenesis, and inflammation were evaluated by cell counting kit-8, flow cytometry, tube formation, and enzyme-linked immunosorbent assays. The subcellular localization of CASC11 was examined by the nuclear/cytoplasmic fractionation assay. The binding of human antigen R (HuR) to CASC11 and HDAC4 was analyzed by RNA immunoprecipitation. HDAC4 stability was determined after actinomycin D treatment. CASC11 was found to be decreased in the CAD cell model. CASC11 upregulation increased cell viability and angiogenesis and reduced apoptosis and inflammation. CASC11 bound to HuR and improved HDAC4 expression. HDAC4 downregulation counteracted the protective role of CASC11 overexpression in CMECs. In summary, CASC11 alleviated ox-LDL-induced injury of CMECs by binding to HuR and stabilizing HDAC4.

Upregulated ribosome pathway plays a key role in HDAC4, improving the survival rate and biofunction of chondrocytes

Aims

To explore the novel molecular mechanisms of histone deacetylase 4 (HDAC4) in chondrocytes via RNA sequencing (RNA-seq) analysis.

Methods

Empty adenovirus (EP) and a HDAC4 overexpression adenovirus were transfected into cultured human chondrocytes. The cell survival rate was examined by real-time cell analysis (RTCA) and EdU and flow cytometry assays. Cell biofunction was detected by Western blotting. The expression profiles of messenger RNAs (mRNAs) in the EP and HDAC4 transfection groups were assessed using whole-transcriptome sequencing (RNA-seq). Volcano plot, Gene Ontology, and pathway analyses were performed to identify differentially expressed genes (DEGs). For verification of the results, the A289E/S246/467/632 A sites of HDAC4 were mutated to enhance the function of HDAC4 by increasing HDAC4 expression in the nucleus. RNA-seq was performed to identify the molecular mechanism of HDAC4 in chondrocytes. Finally, the top ten DEGs associated with ribosomes were verified by quantitative polymerase chain reaction (QPCR) in chondrocytes, and the top gene was verified both in vitro and in vivo.

Results

HDAC4 markedly improved the survival rate and biofunction of chondrocytes. RNA-seq analysis of the EP and HDAC4 groups showed that HDAC4 induced 2,668 significant gene expression changes in chondrocytes (1,483 genes upregulated and 1,185 genes downregulated, p < 0.05), and ribosomes exhibited especially large increases. The results were confirmed by RNA-seq of the EP versus mutated HDAC4 groups and the validations in vitro and in vivo.

Conclusion

The enhanced ribosome pathway plays a key role in the mechanism by which HDAC4 improves the survival rate and biofunction of chondrocytes.

Role of histone deacetylase 9 in human periodontal ligament stem cells autophagy in a tumour necrosis factor α-induced inflammatory environment

Histone deacetylases (HDACs) play important roles in the post-translational modification of histones, which can affect the biological properties of cells, thereby altering disease progression and outcomes. However, it remains unclear how HDAC9, a class II HDAC, affects the autophagy of human periodontal ligament stem cells (hPDLSCs). We aimed to identify its role in autophagy in hPDLSCs in an inflammatory environment and to explore the potential regulatory mechanisms. A rat periodontitis model was induced by ligating the molars with silk thread. Expression of autophagy-related genes and TNF-α was elevated in this model. TNF-α was used to stimulate hPDLSCs to establish an inflammatory environment. In the TNF-α-stimulated hPDLSCs, the expression of ATG7, ATG12, Beclin-1, LC3 and HDAC9 was upregulated, and that of p62 was downregulated. When HDAC9 expression was inhibited, autophagy-related genes expression was downregulated, and p62 expression was upregulated in TNF-α-treated hPDLSCs, indicating that autophagy was inhibited under these conditions. ERK pathway inhibition significantly reduced HDAC9-mediated autophagy in TNF-α-treated hPDLSCs. These findings reveal that autophagy occurred in our rat periodontitis model and that HDAC9 regulated autophagy via ERK pathways in hPDLSCs in the inflammatory environment. HDAC9 is therefore a potential target for the treatment of periodontitis.

LINC1810064F22Rik sequesters miR-206-5p away from HDAC4 to exacerbate allergic airway inflammation and airway remodeling in an ovalbumin mouse model of asthma

Allergic inflammation and airway remodeling frequently occur in asthma. This study clarifies a novel LINC1810064F22Rik-mediated ceRNA mechanism involved in asthma-induced allergic inflammation and airway remodeling based on bioinformatics analysis and in vivo and in vitro experiments. The differentially expressed lncRNAs and downstream effectors were predicted in silico. The targeting relationship among LINC1810064F22Rik, miR-206-5p, and HDAC4 was predicted by bioinformatics analysis, which was further validated by dual luciferase reporter gene assay. The asthma-like airway inflammation was induced in mice using ovalbumin (OVA) sensitization/challenge with immune adjuvant Al(OH)₃, while alveolar epithelial cells (AECs) were exposed to IL-33 to mimic in vitro inflammatory environment. LINC1810064F22Rik and HDAC4 were highly expressed, while miR-206-5p was poorly expressed in the tracheal tissues of OVA mice and the IL-33-treated AECs. The OVA mice and IL-33-treated AECs were subjected to gain- or loss-of-function experiments to detect the interaction of LINC1810064F22Rik/miR-206-5p/HDAC4 axis and their effects on allergic inflammation and airway remodeling. LINC1810064F22Rik competitively bound to miR-206-5p, and miR-206-5p targeted and inhibited HDAC4. The in vivo animal experiments indicated that LINC1810064F22Rik promoted asthma-induced allergic inflammation and airway remodeling by sequestering miR-206-5p away from HDAC4. The evidence provided by our study highlighted the involvement of the LINC1810064F22Rik/miR-206-5p/HDAC4 axis in facilitating allergic airway inflammation and airway remodeling in OVA mice.

HDAC4 in cancer: A multitasking platform to drive not only epigenetic modifications

Controlling access to genomic information and maintaining its stability are key aspects of cell life. Histone acetylation is a reversible epigenetic modification that allows access to DNA and the assembly of protein complexes that regulate mainly transcription but also other activities. Enzymes known as histone deacetylases (HDACs) are involved in the removal of the acetyl-group or in some cases of small hydrophobic moieties from histones but also from the non-histone substrate. The main achievement of HDACs on histones is to repress transcription and promote the formation of more compact chromatin. There are 18 different HDACs encoded in the human genome. Here we will discuss HDAC4, a member of the class IIa family, and its possible contribution to cancer development.

Integrative analysis of Iso-Seq and RNA-seq reveals dynamic changes of alternative promoter, alternative splicing and alternative polyadenylation during Angiotensin II-induced senescence in rat primary aortic endothelial cells

In eukaryotes, alternative promoter (AP), alternative splicing (AS), and alternative polyadenylation (APA) are three crucial regulatory mechanisms that modulate message RNA (mRNA) diversity. Although AP, AS and APA are involved in diverse biological processess, whether they have dynamic changes in Angiotensin II (Ang II) induced senescence in rat primary aortic endothelial cells (RAECs), an important cellular model for studying cardiovascular disease, remains unclear. Here we integrated both PacBio single-molecule long-read isoform sequencing (Iso-Seq) and Illumina short-read RNA sequencing (RNA-seq) to analyze the changes of AP, AS and APA in Ang II-induced senescent RAECs. Iso-Seq generated 36,278 isoforms from 10,145 gene loci and 65.81% of these isoforms are novel, which were further cross-validated by public data obtained by other techonologies such as CAGE, PolyA-Seq and 3'READS. APA contributed most to novel isoforms, followed by AS and AP. Further investigation showed that AP, AS and APA could all contribute to the regulation of isoform, but AS has more dynamic changes compared to AP and APA upon Ang II stimulation. Genes undergoing AP, AS and APA in Ang II-treated cells are enriched in various pathways related to aging or senescence, suggesting that these molecular changes are involved in functional alterations during Ang II-induced senescence. Together, the present study largely improved the annotation of rat genome and revealed gene expression changes at isoform level, extending the understanding of the complexity of gene regulation in Ang II-treated RAECs, and also provided novel clues for discovering the regulatory mechanism undelying Ang II caused vascular senescence and diseases.

Epigenetic and post-translational modifications in autophagy: biological functions and therapeutic targets

Autophagy is a conserved lysosomal degradation pathway where cellular components are dynamically degraded and re-processed to maintain physical homeostasis. However, the physiological effect of autophagy appears to be multifaced. On the one hand, autophagy functions as a cytoprotective mechanism, protecting against multiple diseases, especially tumor, cardiovascular disorders, and neurodegenerative and infectious disease. Conversely, autophagy may also play a detrimental role via pro-survival effects on cancer cells or cell-killing effects on normal body cells. During disorder onset and progression, the expression levels of autophagy-related regulators and proteins encoded by autophagy-related genes (ATGs) are abnormally regulated, giving rise to imbalanced autophagy flux. However, the detailed mechanisms and molecular events of this process are quite complex. Epigenetic, including DNA methylation, histone modifications and miRNAs, and post-translational modifications, including ubiquitination, phosphorylation and acetylation, precisely manipulate gene expression and protein function, and are strongly correlated with the occurrence and development of multiple diseases. There is substantial evidence that autophagy-relevant regulators and machineries are subjected to epigenetic and post-translational modulation, resulting in alterations in autophagy levels, which subsequently induces disease or affects the therapeutic effectiveness to agents. In this review, we focus on the regulatory mechanisms mediated by epigenetic and post-translational modifications in disease-related autophagy to unveil potential therapeutic targets. In addition, the effect of autophagy on the therapeutic effectiveness of epigenetic drugs or drugs targeting post-translational modification have also been discussed, providing insights into the combination with autophagy activators or inhibitors in the treatment of clinical 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.

The role of class IIa histone deacetylases in regulating endothelial function

Vascular endothelial cells (ECs) are monolayer cells located in the inner layer of the blood vessel. Endothelial function is crucial in maintaining local and systemic homeostasis and is precisely regulated by sophisticated signaling pathways and epigenetic regulation. Endothelial dysfunctions are the main factors for the pathophysiological process of cardiovascular and cerebrovascular diseases like atherosclerosis, hypertension, and stroke. In these pathologic processes, histone deacetylases (HDACs) involve in epigenetic regulation by removing acetyl groups from lysine residues of histones and regulating downstream gene expression. Among all HDACs, Class IIa HDACs (HDAC4, 5, 7, 9) contain only an N-terminal regulatory domain, exert limited HDAC activity, and present tissue-specific gene regulation. Here, we discuss and summarize the current understanding of this distinct subfamily of HDACs in endothelial cell functions (such as angiogenesis and immune response) with their molecular underpinnings. Furthermore, we also present new thoughts for further investigation of HDAC inhibitors as a potential treatment in several vascular diseases.

Genome-wide association study for vascular aging highlights pathways shared with cardiovascular traits in Koreans

Vascular aging plays a pivotal role in the morbidity and mortality of older people. Reactive hyperemia index (RHI) detected by pulse amplitude tonometry (PAT) is a non-invasive measure of vascular endothelial function and aging-induced pathogenesis of both microvascular and macrovascular diseases. We conducted a genome-wide association study (GWAS) to comprehensively identify germline genetic variants associated with vascular aging in a Korean population, which revealed 60 suggestive genes underlying angiogenesis, inflammatory response in blood vessels, and cardiovascular diseases. Subsequently, we show that putative protective alleles were significantly enriched in an independent population with decelerated vascular aging phenotypes. Finally, we show the differential mRNA expression levels of putative causal genes in aging human primary endothelial cells via quantitative real-time polymerase chain reaction (PCR). These results highlight the potential contribution of genetic variants in the etiology of vascular aging and may suggest the link between vascular aging and cardiovascular traits.

Association between HDACs and pro-inflammatory cytokine gene expressions in obesity

Histone deacetylases (HDACs) are important players in a variety of physiological and pathological conditions. Few studies have addressed HDAC expressions in human adipose tissue in obese individuals, and their association with pro-inflammatory cytokines. Here, we compared 20 non-obese and 20 obese women to investigate possible changes in gene expressions of HDAC2, 4, 5, and 6 in the subcutaneous adipose tissues (SAT) and visceral adipose tissues (VAT) of these individuals. Our findings showed decreased HDAC5 expression in SAT and elevated HDAC4 expression in VAT from the obese group compared with the non-obese group. Our analyses showed negative correlations between HDAC2, 5, and 6 and the obesity indices and positive correlations between HDAC4 and obesity indices. HDAC2 showed a positive correlation with pro-inflammatory cytokines whereas HDAC4, 5, and 6 were negatively correlated with pro-inflammatory cytokines. Our findings provide new evidence that implicates the important roles of HDACs in obesity and obesity-associated inflammation.

Genomic Analyses for Selective Signatures and Genes Involved in Hot Adaptation Among Indigenous Chickens From Different Tropical Climate Regions

Climate change, especially weather extremes like extreme cold or extreme hot, is a major challenge for global livestock. One of the animal breeding goals for sustainable livestock production should be to breed animals with excellent climate adaptability. Indigenous livestock and poultry are well adapted to the local climate, and they are good resources to study the genetic footprints and mechanism of the resilience to weather extremes. In order to identify selection signatures and genes that might be involved in hot adaptation in indigenous chickens from different tropical climates, we conducted a genomic analysis of 65 indigenous chickens that inhabit different climates. Several important unique positively selected genes (PSGs) were identified for each local chicken group by the cross-population extended haplotype homozygosity (XP-EHH). These PSGs, verified by composite likelihood ratio, genetic differentiation index, nucleotide diversity, Tajima’s D, and decorrelated composite of multiple signals, are related to nerve regulation, vascular function, immune function, lipid metabolism, kidney development, and function, which are involved in thermoregulation and hot adaptation. However, one common PSG was detected for all three tropical groups of chickens via XP-EHH but was not confirmed by other five types of selective sweep analyses. These results suggest that the hot adaptability of indigenous chickens from different tropical climate regions has evolved in parallel by taking different pathways with different sets of genes. The results from our study have provided reasonable explanations and insights for the rapid adaptation of chickens to diverse tropical climates and provide practical values for poultry breeding.

Serum HDAC4 level in rheumatoid arthritis: Longitudinal change during treatment and correlation with clinical outcomes

Objective

Histone deacetylase 4 (HDAC4) modulates immunity, inflammation, and osteoblast differentiation to engage in rheumatoid arthritis (RA) etiology. This study aimed to evaluate the HDAC4 longitudinal change and its relationship with clinical features and outcomes in RA patients.

Methods

Eighty‐three RA patients were enrolled. Their serum HDAC4 level was detected by ELISA at baseline (W0), week (W) 4, W12, and W24 after treatment. RA patients were divided into response or non‐response, low disease activity (LDA) or non‐LDA, remission or non‐remission patients according to their treatment outcomes at W24. Meanwhile, serum HDAC4 was detected by ELISA in 20 osteoarthritis patients and 20 healthy controls (HCs).

Results

HDAC4 level was reduced in RA patients compared with HCs (p < 0.001) and osteoarthritis patients (p = 0.009). HDAC4 was negatively related to some of the disease activity indexes such as C‐reactive protein (p = 0.003), tender joint count (p = 0.025), and disease activity score based on 28 joints (p = 0.013) in RA patients; it was also negatively correlated with TNF‐α (p = 0.003), IL‐6 (p = 0.022), and IL‐17A (p = 0.015). However, the HDAC4 level was not related to different treatment histories or current initiating treatment regimens (all p < 0.05). After treatment, HDAC4 was gradually elevated along with the time (p < 0.001). Interestingly, HDAC4 level at W12 (p = 0.041) and W24 (p = 0.012) was higher in response patients versus non‐response patients, and its level at W24 was higher in LDA patients versus non‐LDA patients (p = 0.019), and in remission patients versus non‐remission patients (p = 0.039).

Conclusion

HDAC4 gradually increases during treatment and its elevation estimates good treatment outcomes in RA patients.

Autophagy at the interface of endothelial cell homeostasis and vascular disease

Autophagy is an essential intracellular process for cellular quality control. It enables cell homeostasis through the selective degradation of harmful protein aggregates and damaged organelles. Autophagy is essential for recycling nutrients, generating energy to maintain cell viability in most tissues and during adverse conditions such as hypoxia/ischaemia. The progressive understanding of the mechanisms modulating autophagy in the vasculature has recently led numerous studies to link intact autophagic responses with endothelial cell (EC) homeostasis and function. Preserved autophagic flux within the ECs has an essential role in maintaining their physiological characteristics, whereas defective autophagy can promote endothelial pro-inflammatory and atherogenic phenotype. However, we still lack a good knowledge of the complete molecular repertoire controlling various aspects of endothelial autophagy and how this is associated with vascular diseases. Here, we provide an overview of the current state of the art of autophagy in ECs. We review the discoveries that have so far defined autophagy as an essential mechanism in vascular biology and analyse how autophagy influences ECs behaviour in vascular disease. Finally, we emphasise opportunities for compounds to regulate autophagy in ECs and discuss the challenges of exploiting them to resolve vascular disease.

HDAC4 promotes the growth and metastasis of gastric cancer via autophagic degradation of MEKK3

Background

Histone deacetylases (HDACs) have been shown to be involved in tumorigenesis, but their precise role and molecular mechanisms in gastric cancer (GC) have not yet been fully elucidated.

Methods

Bioinformatics screening analysis, qRT-PCR, and immunohistochemistry (IHC) were used to identify the expression of HDAC4 in GC. In vitro and in vivo functional assays illustrated the biological function of HDAC4. RNA-seq, GSEA pathway analysis, and western blot revealed that HDAC4 activated p38 MAPK signalling. Immunofluorescence, western blot, and IHC verified the effect of HDAC4 on autophagy. ChIP and dual-luciferase reporter assays demonstrated that the transcriptional regulation mechanism of HDAC4 and ATG4B.

Results

HDAC4 is upregulated in GC and correlates with poor prognosis. In vitro and in vivo assays showed that HDAC4 contributes to the malignant phenotype of GC cells. HDAC4 inhibited the MEF2A-driven transcription of ATG4B and prevented MEKK3 from p62-dependent autophagic degradation, thus activating p38 MAPK signalling. Reciprocally, the downstream transcription factor USF1 enhanced HDAC4 expression by regulating HDAC4 promoter activity, forming a positive feedback loop and continuously stimulating HDAC4 expression and p38 MAPK signalling activation.

Conclusion

HDAC4 plays an oncogenic role in GC, and HDAC4-based targeted therapy would represent a novel strategy for GC treatment.

Transcriptional and Epigenetic Factors Associated with Early Thrombosis of Femoral Artery Involved in Arteriovenous Fistula

Arteriovenous fistulas (AVFs), created for hemodialysis in end-stage renal disease patients, mature through the outward remodeling of the outflow vein. However, early thrombosis and chronic inflammation are detrimental to the process of AVF maturation and precipitate AVF maturation failure. For the successful remodeling of the outflow vein, blood flow through the fistula is essential, but early arterial thrombosis attenuates this blood flow, and the vessels become thrombosed and stenosed, leading to AVF failure. The altered expression of various proteins involved in maintaining vessel patency or thrombosis is regulated by genes of which the expression is regulated by transcription factors and microRNAs. In this study, using thrombosed and stenosed arteries following AVF creation, we delineated transcription factors and microRNAs associated with differentially expressed genes in bulk RNA sequencing data using upstream and causal network analysis. We observed changes in many transcription factors and microRNAs that are involved in angiogenesis; vascular smooth muscle cell proliferation, migration, and phenotypic changes; endothelial cell function; hypoxia; oxidative stress; vessel remodeling; immune responses; and inflammation. These factors and microRNAs play a critical role in the underlying molecular mechanisms in AVF maturation. We also observed epigenetic factors involved in gene regulation associated with these molecular mechanisms. The results of this study indicate the importance of investigating the transcriptional and epigenetic regulation of AVF maturation and maturation failure and targeting factors precipitating early thrombosis and stenosis.

m6 A demethylase ALKBH5 drives denervation-induced muscle atrophy by targeting HDAC4 to activate FoxO3 signalling

BACKGROUND

Skeletal muscle atrophy is a common clinical manifestation of various neurotrauma and neurological diseases. In addition to the treatment of primary neuropathies, it is a clinical condition that should be investigated. FoxO3 activation is an indispensable mechanism in denervation-induced muscle atrophy; however, upstream factors that control FoxO3 expression and activity have not been fully elucidated. N⁶ -methyladenosine (m⁶ A) methylation is a novel mode of epitranscriptional gene regulation that affects several cellular processes. However, the biological significance of m⁶ A modification in FoxO3-dependent atrophy is unknown.

METHODS

We performed gain-of-function and loss-of-function experiments and used denervation-induced muscle atrophy mouse model to evaluate the effects of m⁶ A modification on muscle mass control and FoxO3 activation. m⁶ A-sequencing and mass spectrometry analyses were used to establish whether histone deacetylase 4 (HDAC4) is a mediator of m⁶ A demethylase ALKBH5 regulation of FoxO3. A series of cellular and molecular biological experiments (western blot, immunoprecipitation, half-life assay, m⁶ A-MeRIP-qPCR, and luciferase reporter assays among others) were performed to investigate regulatory relationships among ALKBH5, HDAC4, and FoxO3.

RESULTS

In skeletal muscles, denervation was associated with a 20.7-31.9% decrease in m⁶ A levels (P < 0.01) and a 35.6-115.2% increase in demethylase ALKBH5 protein levels (P < 0.05). Overexpressed ALKBH5 reduced m⁶ A levels, activated FoxO3 signalling, and induced excess loss in muscle wet weight (-10.3% for innervation and -11.4% for denervation, P < 0.05) as well as a decrease in myofibre cross-sectional areas (-35.8% for innervation and -33.3% for denervation, P < 0.05) during innervation and denervation. Specific deletion of Alkbh5 in the skeletal muscles prevented FoxO3 activation and protected mice from denervation-induced muscle atrophy, as evidenced by increased muscle mass (+16.0%, P < 0.05), size (+50.0%, P < 0.05) and MyHC expression (+32.6%, P < 0.05). Mechanistically, HDAC4 was established to be a crucial central mediator for ALKBH5 in enhancing FoxO3 signalling in denervated muscles. ALKBH5 demethylates and stabilizes Hdac4 mRNA. HDAC4 interacts with and deacetylates FoxO3, resulting in a significant increase in FoxO3 expression (+61.3-82.5%, P < 0.01) and activity (+51.6-122.0%, P < 0.001).

CONCLUSIONS

Our findings elucidate on the roles and mechanisms of ALKBH5-mediated m⁶ A demethylation in the control of muscle mass during denervation and activation of FoxO3 signalling by targeting HDAC4. These results suggest that ALKBH5 is a potential therapeutic target for neurogenic muscle atrophy.

Clinical role of serum histone deacetylase 4 measurement in acute ischemic stroke: Relation to disease risk, severity, and prognosis

OBJECTIVE

Histone deacetylase 4 (HDAC4) is engaged in the pathophysiology of acute ischemic stroke (AIS) through modulating atherosclerosis, inflammation and neurocyte death. This study aimed to investigate the clinical role of HDAC4 in AIS.

METHODS

Serum samples were collected from 176 AIS patients and 80 controls for HDAC4 detection by enzyme-linked immunosorbent assay (ELISA). In AIS patients, disease severity was assessed by National Institute of Health Stroke Scale (NIHSS) score and their recurrence-free survival (RFS) and overall survival (OS) were calculated, inflammatory cytokines and adhesion molecules were detected by ELISA.

RESULTS

HDAC4 was declined in AIS patients vs. controls (p < 0.001), it also had certain ability of distinguishing AIS patients from controls with an area under curve of 0.748 (95% confidence interval: 0.689-0.806). Among AIS patients, HDAC4 was negatively linked with NIHSS score (p < 0.001) but no other clinical features (all p > 0.05). Moreover, HDAC4 was negatively related to interleukin (IL)-17 (p = 0.010) and tumor necrosis factor alpha (p = 0.001), while it was not correlated with IL-1β (p = 0.081) or IL-6 (p = 0.074). Furthermore, HDAC4 was negatively associated with intercellular cell adhesion molecule-1 (p < 0.001) and vascular cell adhesion molecule-1 (p = 0.003). During a median follow-up of 19.0 months, 17 (9.7%) patients had recurrence and 10 (5.7%) patients died. Additionally, high HDAC4 was linked with prolonged RFS (p = 0.044) but not OS (p = 0.079).

CONCLUSION

HDAC4 possesses the potential to monitor disease risk, inflammation and estimate recurrence of AIS, while further study with larger scale is needed to verify our findings.

Effect of circRNA_FOXO3 rs12196996 polymorphism and FOXO3 rs2232365 polymorphism on survival rate and severity of intensive care unit-acquired sepsis

The expression of circRNA_FOXO3 was found to be positively associated with the expression of Forkhead Box O3 (FOXO3), which is targeted and regulated by miR-23a. Polymorphisms in rs12196996 and rs2232365 have been reported in various diseases. In this study, we recruited intensive care unit (ICU)-acquired sepsis patients and grouped them according to their genotypes of rs12196996 and rs2232365. Quantitative real-time PCR was performed to analyze the expression of circRNA_FOXO3, FOXO3 mRNA, and miR-23a. ELISA was carried out to evaluate the abundance of cytokines and luciferase assay was used to explore the inhibitory role of miR-23a on circRNA_FOXO3 and FOXO3. Accordingly, we found that rs12196996 GG and rs2232365 AA were significantly correlated with prolonged survival of ICU-acquired sepsis patients. Rs12196996 GG and rs2232365 AA were also correlated with increased level of miR-23a, IL-10 and decreased level of TNF, IL-2, IFN, IL-6 and IL-1β in the peripheral blood cell samples of patients with ICU-acquired sepsis. The luciferase activity of wild-type (WT) circRNA_FOXO3 and FOXO3 were severely reduced by miR-23a. MiR-23a precursors could effectively suppress the expression of circRNA_FOXO3 and FOXO3 in the cells. Moreover, LPS-induced cell viability loss and dysregulation of cytokines were effectively restored by the knockdown of FOXO3 or circRNA_FOXO3 siRNA in the cells. This study revealed that the minor allele of rs12196996 polymorphism and rs2232365 polymorphism collaboratively contributed to the increased survival and suppressed severity of ICU-acquired sepsis.

Targeting Epigenetic Mechanisms in Vascular Aging

Environment, diseases, lack of exercise, and aged tendency of population have becoming crucial factors that induce vascular aging. Vascular aging is unmodifiable risk factor for diseases like diabetes, hypertension, atherosclerosis, and hyperlipidemia. Effective interventions to combat this vascular function decline is becoming increasingly urgent as the rising hospitalization rate caused by vascular aging-related diseases. Fortunately, recent transformative omics approaches have enabled us to examine vascular aging mechanisms at unprecedented levels and precision, which make our understanding of slowing down or reversing vascular aging become possible. Epigenetic viz. DNA methylation, histone modifications, and non-coding RNA-based mechanisms, is a hallmark of vascular aging, its deregulation leads to aberrant transcription changes in tissues. Epigenetics mechanisms by mediating covalent modifications to DNA and histone proteins, consequently, influence the sensitivity and activities of signaling pathways in cells and tissues. A growing body of evidence supports correlations between epigenetic changes and vascular aging. In this article, we will provide a comprehensive overview of epigenetic changes associated with vascular aging based on the recent findings with a focus on molecular mechanisms of action, strategies to reverse epigenetic changes, and future perspectives.

New insights of epigenetics in vascular and cellular senescence

Vascular senescence plays a vital role in cardiovascular diseases and it is closely related to cellular senescence. At the molecular level, aging begins with a single cell, and it is characterized by telomere shortening, mitochondrial dysfunction, stem cell exhaustion, epigenetic changes, and so on. Epigenetics is an independent discipline that modifies DNA activity without altering the DNA sequence. The application of epigenetics helps to alleviate the occurrence of human diseases, inhibit senescence, and even inhibit tumor occurrence. Epigenetics mainly includes the modification of DNA, histone, and noncoding RNA. Herein, the application of epigenetics in vascular senescence and aging has been reviewed to provide the prospects and innovative inspirations for future research.

Mipsagargin: The Beginning-Not the End-of Thapsigargin Prodrug-Based Cancer Therapeutics

Søren Brøgger Christensen isolated and characterized the cell-penetrant sesquiterpene lactone Thapsigargin (TG) from the fruit Thapsia garganica. In the late 1980s/early 1990s, TG was supplied to multiple independent and collaborative groups. Using this TG, studies documented with a large variety of mammalian cell types that TG rapidly (i.e., within seconds to a minute) penetrates cells, resulting in an essentially irreversible binding and inhibiting (IC₅₀~10 nM) of SERCA 2b calcium uptake pumps. If exposure to 50–100 nM TG is sustained for >24–48 h, prostate cancer cells undergo apoptotic death. TG-induced death requires changes in the cytoplasmic Ca²⁺, initiating a calmodulin/calcineurin/calpain-dependent signaling cascade that involves BAD-dependent opening of the mitochondrial permeability transition pore (MPTP); this releases cytochrome C into the cytoplasm, activating caspases and nucleases. Chemically unmodified TG has no therapeutic index and is poorly water soluble. A TG analog, in which the 8-acyl groups is replaced with the 12-aminododecanoyl group, afforded 12-ADT, retaining an EC₅₀ for killing of <100 nM. Conjugation of 12-ADT to a series of 5–8 amino acid peptides was engineered so that they are efficiently hydrolyzed by only one of a series of proteases [e.g., KLK3 (also known as Prostate Specific Antigen); KLK2 (also known as hK2); Fibroblast Activation Protein Protease (FAP); or Folh1 (also known as Prostate Specific Membrane Antigen)]. The obtained conjugates have increased water solubility for systemic delivery in the blood and prevent cell penetrance and, thus, killing until the TG-prodrug is hydrolyzed by the targeting protease in the vicinity of the cancer cells. We summarize the preclinical validation of each of these TG-prodrugs with special attention to the PSMA TG-prodrug, Mipsagargin, which is in phase II clinical testing.

Comprehensive analysis of Transcription Factors identified novel prognostic biomarker in human bladder cancer

Background: Transcriptional factors (TFs) are responsible for regulating the transcription of pro-oncogenes and tumor suppressor genes in the process of tumor development. However, the role of these transcription factors in Bladder cancer (BCa) remains unclear. And the main purpose of this research is to explore the possibility of these TFs serving as biomarkers for BCa.

Methods: We analyzed the differential expression of TFs in BCa from The Cancer Genome Atlas (TCGA) online database, identified 408 up-regulated TFs and 751down-regulated TFs. We obtained some hub genes via WGCNA model and detected the RNAs level in BCa cells and tissues. Then, the relationship between the expression and clinicopathological parameters was further investigated. Kaplan-Meier curves and the log-rank test were carried out to analyze the relationship between NFATC1, AKNA and five-TFs combination and overall survival (OS). And RT-PCR assay was conducted to further consolidate and verify these results.

Results: There were significant differences in the expression of five TFs (CBX7, AKNA, HDAC4, EBF2 and NFATC1) between bladder cancer and normal bladder tissue. In BCa tissue and cell lines, the five TFs were frequently down-regulated, and closely related to poor prognosis. Moreover, the RT-PCR results of five TFs in bladder cancer and normal bladder tissue were consistent with the database results, and reduced TFs could significantly induce or restrain the transcription of many critical factors. The expression level of AKNA and NFATC1 could serve as independent biomarker to predict the overall survival (P<0.05). And the above five TFs combined detection of bladder cancer has higher sensitivity and specificity. Furthermore, differential neutrophils expression between high-risk and low-risk were found, which consolidated the role and function of the five TFs combination model in the progression of BCa.

Conclusions: Our analysis effectively provides a newly TFs-associated prognostic model for bladder cancer. The combination of five identified-TFs is an independent prognostic biomarker, which could serve as a more effective therapeutic target for BCa patients.

Sex-Specific Effects of Plastic Caging in Murine Viral Myocarditis

Background: Myocarditis is an inflammatory heart disease caused by viral infections that can lead to heart failure, and occurs more often in men than women. Since animal studies have shown that myocarditis is influenced by sex hormones, we hypothesized that endocrine disruptors, which interfere with natural hormones, may play a role in the progression of the disease. The human population is exposed to the endocrine disruptor bisphenol A (BPA) from plastics, such as water bottles and plastic food containers. Methods: Male and female adult BALB/c mice were housed in plastic versus glass caging, or exposed to BPA in drinking water versus control water. Myocarditis was induced with coxsackievirus B3 on day 0, and the endpoints were assessed on day 10 post infection. Results: We found that male BALB/c mice that were exposed to plastic caging had increased myocarditis due to complement activation and elevated numbers of macrophages and neutrophils, whereas females had elevated mast cell activation and fibrosis. Conclusions: These findings show that housing mice in traditional plastic caging increases viral myocarditis in males and females, but using sex-specific immune mechanisms.

Blood DNA Methylation and Incident Coronary Heart Disease: Evidence From the Strong Heart Study

Importance

American Indian communities experience a high burden of coronary heart disease (CHD). Strategies are needed to identify individuals at risk and implement preventive interventions.

Objective

To investigate the association of blood DNA methylation (DNAm) with incident CHD using a large number of methylation sites (cytosine-phosphate-guanine [CpG]) in a single model.

Design, Setting, and Participants

This prospective study, including a discovery cohort (the Strong Heart Study [SHS]) and 4 additional cohorts (the Women's Health Initiative [WHI], the Framingham Heart Study [FHS], the Atherosclerosis Risk in Communities Study ([ARIC]-Black, and ARIC-White), evaluated 12 American Indian communities in 4 US states; African American women, Hispanic women, and White women throughout the US; White men and White women from Massachusetts; and Black men and women and White men and women from 4 US communities. A total of 2321 men and women (mean [SD] follow-up, 19.1 [9.2] years) were included in the SHS, 1874 women (mean [SD] follow-up, 15.8 [5.9] years) in the WHI, 2128 men and women (mean [SD] follow-up, 7.7 [1.8] years) in the FHS, 2114 men and women (mean [SD] follow-up, 20.9 [7.2] years) in the ARIC-Black, and 931 men and women (mean [SD] follow-up, 20.9 [7.2] years) in the ARIC-White. Data were collected from May 1989 to December 2018 and analyzed from February 2019 to May 2021.

Exposure

Blood DNA methylation.

Main Outcome and Measure

Using a high-dimensional time-to-event elastic-net model for the association of 407 224 CpG sites with incident CHD in the SHS (749 events), this study selected the differentially methylated CpG positions (DMPs) selected in the SHS and evaluated them in the WHI (531 events), FHS (143 events), ARIC-Black (350 events), and ARIC-White (121 events) cohorts.

Results

The median (IQR) age of participants in SHS was 55 (49-62) years, and 1359 participants (58.6%) were women. Elastic-net models selected 505 DMPs associated with incident CHD in the SHS beyond established risk factors, center, blood cell counts, and genetic principal components. Among those DMPs, 33 were commonly selected in 3 or 4 of the other cohorts and the pooled hazard ratios from the standard Cox models were significant at P < .05 for 10 of the DMPs. For example, the hazard ratio (95% CI) for CHD comparing the 90th and 10th percentiles of differentially methylated CpGs was 0.86 (0.78-0.95) for cg16604233 (tagged to COL11A2) and 1.23 (1.08-1.39) for cg09926486 (tagged to FRMD5). Some of the DMPs were consistent in the direction of the association; others showed associations in opposite directions across cohorts. Untargeted independent elastic-net models of CHD showed distinct DMPs, genes, and network of genes in the 5 cohorts.

Conclusions and Relevance

In this multi-cohort study, blood-based DNAm findings supported an association between a complex blood epigenomic signature and CHD that was largely different across populations.

The loss of histone deacetylase 4 in macrophages exacerbates hepatic and adipose tissue inflammation in male but not in female mice with diet-induced non-alcoholic steatohepatitis

Epigenetic regulation in macrophages plays a crucial role in the inflammatory response of cells. We investigated the role of macrophage histone deacetylase 4 (HDAC4) in diet-induced obesity and non-alcoholic steatohepatitis using macrophage-specific Hdac4 knockout mice (Hdac4^MKO ). Hdac4 floxed control (Hdac4^fl/fl ) and Hdac4^MKO mice were fed a regular chow diet or an obesogenic high-fat/high-sucrose/high-cholesterol (HF/HS/HC) diet for 12 weeks. The loss of macrophage Hdac4, compared with Hdac4^fl/fl control, aggravated the diet-induced inflammation in the liver and white adipose tissue only in male mice. Splenic monocytes isolated from male mice fed the HF/HS/HC diet showed increased lipopolysaccharide (LPS) sensitivity and decreased Ly6C-/Ly6C+ ratios in male Hdac4^MKO mice, but not in females. Bone marrow-derived macrophages (BMMs) from male Hdac4^MKO mice had a lesser efferocytotic capacity but higher proinflammatory gene expression upon LPS stimulation than male Hdac4^fl/fl mice. However, female Hdac4^MKO BMMs exhibited the opposite responses. The induction of estrogen receptor α (ERα, Esr1) expression by LPS was less in male but more in female Hdac4^MKO BMMs than Hdac4^fl/fl BMMs. Moreover, overexpression of human HDAC4 decreased basal expression of Esr1 and abolished its induction by LPS. Inhibition of ERα increased Hdac4 with induction of inflammatory genes, whereas activation of ERα decreased Hdac4 with reduction of inflammatory genes in male and female Hdac4^fl/fl BMMs treated with LPS. However, regardless of the inhibition or activation of ERα, proinflammatory genes were induced by LPS more in male Hdac4^MKO BMMs than Hdac4^fl/fl cells, whereas cells in females showed opposite responses. In conclusion, this study suggests that the lack of macrophage Hdac4 aggravates hepatic and white adipose inflammation in male mice with diet-induced obesity and non-alcoholic steatohepatitis, and not in female mice. HDAC4 and ERα appear to counteract each other, but ERα may not be a major player in sex-dependent inflammatory responses in macrophages deficient in HDAC4. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The mechanisms of vascular aging

Vascular senescence is one of the hotspots in current research. With global average life expectancy increasing, delaying or reducing aging and age-related diseases has become a pressing issue for improving quality of life. Vascular senescence is an independent risk factor for age-related cardiovascular diseases (CVD) and results in the deterioration of CVD. Nevertheless, the underlying mechanisms of the vascular senescence have not been expressly illustrated. In this review, we attempt to summarize the recent literature in the field and discuss the major mechanisms involved in vascular senescence. We also underline key molecular aspects of aging-associated vascular dysfunction in the attempt to highlight potential innovative therapeutic targets to delay the onset of age-related diseases.

The role of G protein-coupled receptor kinase 4 in cardiomyocyte injury after myocardial infarction

AIMS

G protein-coupled receptor kinase 4 (GRK4) has been reported to play an important role in hypertension, but little is known about its role in cardiomyocytes and myocardial infarction (MI). The goal of present study is to explore the role of GRK4 in the pathogenesis and progression of MI.

METHODS AND RESULTS

We studied the expression and distribution pattern of GRK4 in mouse heart after MI. GRK4 A486V transgenic mice, inducible cardiomyocyte-specific GRK4 knockout mice, were generated and subjected to MI with their control mice. Cardiac infarction, cardiac function, cardiomyocyte apoptosis, autophagic activity, and HDAC4 phosphorylation were assessed. The mRNA and protein levels of GRK4 in the heart were increased after MI. Transgenic mice with the overexpression of human GRK4 wild type (WT) or human GRK4 A486V variant had increased cardiac infarction, exaggerated cardiac dysfunction and remodelling. In contrast, the MI-induced cardiac dysfunction and remodelling were ameliorated in cardiomyocyte-specific GRK4 knockout mice. GRK4 overexpression in cardiomyocytes aggravated apoptosis, repressed autophagy, and decreased beclin-1 expression, which were partially rescued by the autophagy agonist rapamycin. MI also induced the nuclear translocation of GRK4, which inhibited autophagy by increasing HDAC4 phosphorylation and decreasing its binding to the beclin-1 promoter. HDAC4 S632A mutation partially restored the GRK4-induced inhibition of autophagy. MI caused greater impairment of cardiac function in patients carrying the GRK4 A486V variant than in WT carriers.

CONCLUSION

GRK4 increases cardiomyocyte injury during MI by inhibiting autophagy and promoting cardiomyocyte apoptosis. These effects are mediated by the phosphorylation of HDAC4 and a decrease in beclin-1 expression.

Bisphenol A increases TLR4-mediated inflammatory response by up-regulation of autophagy-related protein in lung of adolescent mice

In previous studies we found that bisphenol A (BPA) aggravated OVA-induced lung inflammation. The aim of this research was to determine whether BPA exposure alone also induced inflammatory response in the lungs, which mechanism was associated with TLR4/NF-κB signaling pathway and the activation of mTOR-mediated autophagy. Female C57BL/6 mice aged 4 weeks were randomly divided into three groups (10/group): control group, 0.1 and 0.2 μg mL^-1 BPA groups. BPA induced the pathological changes in the lung and increased the levels of cytokines and inflammatory cells, as well as affected autophagy related proteins expression. In addition, the RAW264.7 cell culture experiment was conducted in order to confirm the role of autophagy. We found that BPA can enhance autophagy flux by enhancing autophagosome formation. It was further confirmed the details of the mechanism of action with chloroquine (CQ, a compound that inhibits the fusion of autophagosomes and lysosomes) intervention. The inhibition of autophagy led to down-regulation of expression levels associated with inflammation. This research results indicated that BPA induced inflammatory response in vitro and in vivo, and its mechanism may be related to TLR4/NF-κB signaling pathway and the activation of mTOR-mediated autophagy. After autophagy was suppressed, the inflammatory response also weakened. Our findings provide a new perspective into the mechanisms underlying inflammatory responses induced by the environmental exposure. These findings indicate that therapeutic strategies targeting autophagy may provide a new method for the treatment of inflammatory diseases.

Endurance Training Regulates Expression of Some Angiogenesis-Related Genes in Cardiac Tissue of Experimentally Induced Diabetic Rats

Exercise can ameliorate cardiovascular dysfunctions in the diabetes condition, but its precise molecular mechanisms have not been entirely understood. The aim of the present study was to determine the impact of endurance training on expression of angiogenesis-related genes in cardiac tissue of diabetic rats. Thirty adults male Wistar rats were randomly divided into three groups (N = 10) including diabetic training (DT), sedentary diabetes (SD), and sedentary healthy (SH), in which diabetes was induced by a single dose of streptozotocin (50 mg/kg). Endurance training (ET) with moderate-intensity was performed on a motorized treadmill for six weeks. Training duration and treadmill speed were increased during five weeks, but they were kept constant at the final week, and slope was zero at all stages. Real-time polymerase chain reaction (RT-PCR) analysis was used to measure the expression of myocyte enhancer factor-2C (MEF2C), histone deacetylase-4 (HDAC4) and Calmodulin-dependent protein kinase II (CaMKII) in cardiac tissues of the rats. Our results demonstrated that six weeks of ET increased gene expression of MEF2C significantly (p < 0.05), and caused a significant reduction in HDAC4 and CaMKII gene expression in the DT rats compared to the SD rats (p < 0.05). We concluded that moderate-intensity ET could play a critical role in ameliorating cardiovascular dysfunction in a diabetes condition by regulating the expression of some angiogenesis-related genes in cardiac tissues.

Acetylation Modification During Autophagy and Vascular Aging

Vascular aging plays a pivotal role in the morbidity and mortality of elderly people. Decrease in autophagy leads to acceleration of vascular aging, while increase in autophagy leads to deceleration of vascular aging. And emerging evidence indicates that acetylation plays an important role in autophagy regulation; therefore, recent research has focused on an in-depth analysis of the mechanisms underlying this regulation. In this review, current knowledge on the role of acetylation of autophagy-related proteins and the mechanisms by which acetylation including non-autophagy-related acetylation and autophagy related acetylation regulate vascular aging have been discussed. We conclude that the occurrence of acetylation modification during autophagy is a fundamental mechanism underlying autophagy regulation and provides promising targets to retard vascular aging.

Qiliqiangxin alleviates Ang II-induced CMECs apoptosis by downregulating autophagy via the ErbB2-AKT-FoxO3a axis

Our previous work revealed the protective effect of Qiliqiangxin (QLQX) on cardiac microvascular endothelial cells (CMECs), but the underlying mechanisms remain unclear. We aimed to investigate whether QLQX exerts its protective effect against high-concentration angiotensin II (Ang II)-induced CMEC apoptosis through the autophagy machinery. CMECs were cultured in high-concentration Ang II (1 μM) medium in the presence or absence of QLQX for 48 h. We found that QLQX obviously inhibited Ang II-triggered autophagosome synthesis and apoptosis in cultured CMECs. QLQX-mediated protection against Ang II-induced CMEC apoptosis was reversed by the autophagy activator rapamycin. Specifically, deletion of ATG7 in cultured CMECs indicated a detrimental role of autophagy in Ang II-induced CMEC apoptosis. QLQX reversed Ang II-mediated ErbB2 phosphorylation impairment. Furthermore, inhibition of ErbB2 phosphorylation with lapatinib in CMECs revealed that QLQX-induced downregulation of Ang II-activated autophagy and apoptosis was ErbB2 phosphorylation-dependent via the AKT-FoxO3a axis. Activation of ErbB2 phosphorylation by Neuregulin-1β achieved a similar CMEC-protective effect as QLQX in high-concentration Ang II medium, and this effect was also abolished by autophagy activation. These results show that the CMEC-protective effect of QLQX under high-concentration Ang II conditions could be partly attributable to QLQX-mediated ErbB2 phosphorylation-dependent downregulation of autophagy via the AKT-FoxO3a axis.

HDAC5 inhibition reduces angiotensin II-induced vascular contraction, hypertrophy, and oxidative stress in a mouse model

Non-specific histone deacetylase (HDAC) inhibition reduces high blood pressure in essential hypertensive animal models. However, the exact HDAC isoforms that play a critical role in controlling hypertension are not known. Here, we investigated the role of HDAC5 in vascular contraction, hypertrophy, and oxidative stress in the context of angiotensin II (Ang II)-induced hypertension. Genetic deletion of HDAC5 and treatment with class IIa HDAC inhibitors (TMP269 and TMP195) prevented Ang II-induced increases in blood pressure and arterial wall thickness. Hdac5-knockout mice were also resistant to the thromboxane A2 agonist (U46619)-induced vascular contractile response. Furthermore, the expression of Rho-associated protein kinase (ROCK) 2 was downregulated in the aortas of Ang II-treated Hdac5-knockout mice. Knockdown of HDAC5, RhoA, or ROCK2 reduced collagen gel contraction, whereas silencing of ROCK1 increased it. VSMC hypertrophy reduced on knocking down HDAC5, ROCK1, and ROCK2. Here we showed that genetic deletion of HDAC5 and pharmacological inhibition of class IIa HDACs ameliorated Ang II-induced ROS generation. Moreover, ROCK1 and ROCK2, the downstream targets of HDAC5, influenced ROS generation. The relative protein levels of HDAC5, ROCK1, and ROCK2 were increased both in the cytoplasm and nuclear fraction in response to Ang II stimulation in vascular smooth muscle cells. Inhibition of HDAC5 expression or activity reduced vascular hypertrophy, vasoconstriction, and oxidative stress in the Ang II-induced hypertension model. These findings indicate that HDAC5 may serve as a potential target in the treatment of hypertension.

Beneficial Effects of a Mixture of Algae and Extra Virgin Olive Oils on the Age-Induced Alterations of Rodent Skeletal Muscle: Role of HDAC-4

Aging is associated with a progressive decline in skeletal muscle mass, strength and function (sarcopenia). We have investigated whether a mixture of algae oil (25%) and extra virgin olive oil (75%) could exert beneficial effects on sarcopenia. Young (3 months) and old (24 months) male Wistar rats were treated with vehicle or with the oil mixture (OM) (2.5 mL/kg) for 21 days. Aging decreased gastrocnemius weight, total protein, and myosin heavy chain mRNA. Treatment with the OM prevented these effects. Concomitantly, OM administration decreased the inflammatory state in muscle; it prevented the increase of pro-inflammatory interleukin-6 (IL-6) and the decrease in anti-inflammatory interleukin-10 (IL-10) in aged rats. The OM was not able to prevent aging-induced alterations in either the insulin-like growth factor I/protein kinase B (IGF-I/Akt) pathway or in the increased expression of atrogenes in the gastrocnemius. However, the OM prevented decreased autophagy activity (ratio protein 1A/1B-light chain 3 (LC3b) II/I) induced by aging and increased expression of factors related with muscle senescence such as histone deacetylase 4 (HDAC-4), myogenin, and IGF-I binding protein 5 (IGFBP-5). These data suggest that the beneficial effects of the OM on muscle can be secondary to its anti-inflammatory effect and to the normalization of HDAC-4 and myogenin levels, making this treatment an alternative therapeutic tool for sarcopenia.

Smyd3-PARP16 axis accelerates unfolded protein response and vascular aging

Vascular endothelial cell senescence and endoplasmic reticulum (ER) stress induced unfolded protein response (UPR) are two critical contributors to individual aging. However, whether these two biological events have crosstalk and are controlled by shared upstream regulators are largely unknown. Here, we found PARP16, a member of the Poly (ADP-ribose) polymerases family that tail-anchored ER transmembrane, was upregulated in angiotensin II (Ang II)-induced vascular aging and promoted UPR. Further, PARP16 was epigenetically upregulated by Smyd3, a histone H3 lysine 4 methyltransferase that bound to the promotor region of Parp16 gene and increased H3K4me3 level to activate its host gene’s transcription. Intervention of either Smyd3 or PARP16 ameliorated vascular aging associated phenotypes in both cell and mice models. This study identified Smyd3-PARP16 as a novel signal axis in regulating UPR and endothelial senescence, and targeting this axis has implications in preventing vascular aging and related diseases.

Epigenetics and Vascular Senescence-Potential New Therapeutic Targets?

Epigenetics is defined as the heritable alterations of gene expression without changes to the coding sequence of DNA. These alterations are mediated by processes including DNA methylation, histone modifications, and non-coding RNAs mechanisms. Vascular aging consists of both structural and functional changes in the vasculature including pathological processes that drive progression such as vascular cell senescence, inflammation, oxidation stress, and calcification. As humans age, these pathological conditions gradually accumulate, driven by epigenetic alterations, and are linked to various aging-related diseases. The development of drugs targeting a spectrum of epigenetic processes therefore offers novel treatment strategies for the targeting of age-related diseases. In our previous studies, we identified HDAC4, JMJD3, Fra-1, and GATA4 as potential pharmacological targets for regulating vascular inflammation, injury, and senescence.

The association between poverty and gene expression within peripheral blood mononuclear cells in a diverse Baltimore City cohort

Socioeconomic status (SES), living in poverty, and other social determinants of health contribute to health disparities in the United States. African American (AA) men living below poverty in Baltimore City have a higher incidence of mortality when compared to either white males or AA females living below poverty. Previous studies in our laboratory and elsewhere suggest that environmental conditions are associated with differential gene expression (DGE) patterns in peripheral blood mononuclear cells (PBMCs). DGE have also been associated with hypertension and cardiovascular disease (CVD) and correlate with race and sex. However, no studies have investigated how poverty status associates with DGE between male and female AAs and whites living in Baltimore City. We examined DGE in 52 AA and white participants of the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) cohort, who were living above or below 125% of the 2004 federal poverty line at time of sample collection. We performed a microarray to assess DGE patterns in PBMCs from these participants. AA males and females living in poverty had the most genes differentially-expressed compared with above poverty controls. Gene ontology (GO) analysis identified unique and overlapping pathways related to the endosome, single-stranded RNA binding, long-chain fatty-acyl-CoA biosynthesis, toll-like receptor signaling, and others within AA males and females living in poverty and compared with their above poverty controls. We performed RT-qPCR to validate top differentially-expressed genes in AA males. We found that KLF6, DUSP2, RBM34, and CD19 are expressed at significantly lower levels in AA males in poverty and KCTD12 is higher compared to above poverty controls. This study serves as an additional link to better understand the gene expression response in peripheral blood mononuclear cells in those living in poverty.