Epigenetics in diabetic cardiomyopathy.

Diabetic cardiomyopathy (DCM) is a critical complication that poses a significant threat to the health of patients with diabetes. The intricate pathological mechanisms of DCM cause diastolic dysfunction, followed by impaired systolic function in the late stages. Accumulating researches have revealed the association between DCM and various epigenetic regulatory mechanisms, including DNA methylation, histone modifications, non-coding RNAs, and other epigenetic molecules. Recently, a profound understanding of epigenetics in the pathophysiology of DCM has been broadened owing to advanced high-throughput technologies, which assist in developing potential therapeutic strategies. In this review, we briefly introduce the epigenetics regulation and update the relevant progress in DCM. We propose the role of epigenetic factors and non-coding RNAs (ncRNAs) as potential biomarkers and drugs in DCM diagnosis and treatment, providing a new perspective and understanding of epigenomics in DCM.

Super-enhancer-driven LncRNA PPARα-seRNA exacerbates glucolipid metabolism and diabetic cardiomyopathy via recruiting KDM4B.

OBJECTIVE: Aberrant glucolipid metabolism in the heart is a characteristic factor in diabetic cardiomyopathy (DbCM). Super-enhancers-driven noncoding RNAs (seRNAs) are emerging as powerful regulators in the progression of cardiac diseases. However, the functions of seRNAs in DbCM have not been fully elucidated. METHODS: Super enhancers and their associated seRNAs were screened and identified by H3K27ac ChIP-seq data in the Encyclopedia of DNA Elements (ENCODE) dataset. A dual-luciferase reporter assay was performed to analyze the function of super-enhancers on the transcription of peroxisome proliferator-activated receptor α-related seRNA (PPARα-seRNA). A DbCM mouse model was established using db/db leptin receptor-deficient mice. Adeno-associated virus serotype 9-seRNA (AAV9-seRNA) was injected via the tail vein to evaluate the role of seRNA in DbCM. The underlying mechanism was explored through RNA pull-down, RNA and chromatin immunoprecipitation, and chromatin isolation by RNA purification. RESULTS: PPARα-seRNA was regulated by super-enhancers and its levels were increased in response to high glucose and palmitic acid stimulation in cardiomyocytes. Functionally, PPARα-seRNA overexpression aggravated lipid deposition, reduced glucose uptake, and repressed energy production. In contrast, PPARα-seRNA knockdown ameliorated metabolic disorder in vitro. In vivo, overexpression of PPARα-seRNA exacerbated cardiac metabolic disorder and deteriorated cardiac dysfunction, myocardial fibrosis, and hypertrophy in DbCM. Mechanistically, PPARα-seRNA bound to the histone demethylase KDM4B (Lysine-specific demethylase 4B) and decreased H3K9me3 levels in the promoter region of PPARα, ultimately enhancing its transcription. CONCLUSIONS: Our study revealed the pivotal function of a super-enhancer-driven long noncoding RNA (lncRNA), PPARα-seRNA, in the deterioration of cardiac function and the exacerbation of metabolic abnormalities in diabetic cardiomyopathy, which recruited KDM4B to the promoter region of PPARα and repression of its transcription. This suggests a promising therapeutic strategy for the treatment of DbCM.

CircSMAD3 represses SMAD3 phosphorylation and ameliorates cardiac remodeling by recruiting YBX1.

Circular RNA (circRNA) has emerged as potential therapeutic targets for cardiovascular diseases. Given the central role of the TGFß signaling pathway in cardiac remodeling and its potential as a therapeutic target, we hypothesized that a circRNA from this pathway could modulate cardiac remodeling and serve as a heart failure treatment. Therefore, we identified a circRNA, named circSMAD3, that was significantly reduced in murine heart failure models. Functionally, circSMAD3 mitigated cardiomyocyte hypertrophy and inhibited cardiac fibroblast activation in vitro. Mechanistically, circSMAD3 interacts with YBX1, stabilizing it and facilitating its binding to SMAD3 in the nucleus, disrupting the TGFß/SMAD3 signaling pathway, and ultimately restoring cardiac remodeling. This study highlights circSMAD3 as a promising therapeutic target for heart failure treatment.

Elevated Homocysteine and C-reactive Protein Levels Independently Predict Worsening Prognosis after Stroke in Chinese Patients / 华中科技大学学报（医学）（英德文版）

Increased plasma total homocysteine (tHcy) and high sensitivity C-reactive protein (hsCRP) levels are independent risk factors for cardiovascular disease. However, the predictive value of tHcy in combination with hsCRP in patients with stroke is not known. To determine the relationship between tHcy and hsCRP, we enrolled 291 patients with first-onset stroke (196 ischemic and 95 hemorrhagic). Plasma tHcy and hsCRP levels were measured and subsequent vascular events and deaths were determined over a 5-year period. Using the arbitrary cutoff for tHcy (＜18 μrnol/L and ≥18 μtmol/L) and hsCRP (＜1 mg/L, 1-3 mg/L and ＞3 mg/L), the patients were divided into 6 groups.Survival analysis showed that the probability of death or new vascular events during a 5-year follow-up increased according to tHcy and hsCRP levels (P＜0.01). The relative risk (RR) of death or new vascular events was 4.67 (95% CI, 1.96 to 11.14, P=0.001) in patients with high tHcy (≥18μmol/L) and hsCRP (＞3 mg/L) compared with those with low tHcy (＜18 μmol/L) and hsCRP (＜1 mg/L). The increased tHcy level (≥18 μ mol/L) combined with increased hsCRP level (＞3 mg/L) was still significantly associated with the risk of death or new vascular events (RR, 4.10, 95% CI, 1.61 to 10.45, P=0.003) even when adjusted for other risk factors at inclusion. The combination of increased tHcy and hsCRP levels had a stronger predictive value than increased hsCRP alone or increased tHcy level alone. Further studies are required to evaluate the potential decrease in risks associated with lowering both Hcy and hsCRP levels in patients that present with both increased tHcy and hsCRP.

Throat Infection, Neck and Chest Pain and Cardiac Response: A Persistent Infection-Related Clinical Syndrome / 华中科技大学学报（医学）（英德文版）

Dizziness,chest discomfort,chest depression and dyspnea are a group of symptoms that are common complaints in clinical practice. Patients with these symptoms are usually informed that while neurosis consequent to coronary heart disease is excluded nonetheless they remain unhealthy with no rational explanation or treatment. 165 cases of these symptoms and 85 control subjects were reviewed and underwent further medical history inquiry,routine EKG test and cardiac ultrasound examination. Thirty-five patients received coronary artery angiography to exclude coronary heart disease. Serum myocardial autoantibodies against beta1-adrenoceptor,alpha-myosin heavy chain,M2-muscarinie receptor and adenine-nucleotide translocator were tested,and inflammatory cytokines and high sensitivity C-reaction protein were measured and lymphocyte subclass was assayed by flow cytometry. All patients had a complex of four symptoms or tetralogy: (1) persistent throat or upper respiratory tract infection,(2) neck pain,(3) chest pain and (4) chest depression or dyspnea,some of them with anxiety. Anti-myocardial autoantibodies (AMCAs) were present in all patients vs. 8% in and CD4-CD8+ lymphocytes were significantly higher and CD56+ lymphocytes lower in patients than those in controls (P<0.01). The ratio of serum pathogen antibodies positive against Coxsackie virus-B,cytomegalovirus,Mycoplasma pneumoniae and Chlamydia pneumoniae were all markedly higher in patients. These data led to identification of a persistent respiratory infection-related clinical syndrome,including persistent throat infection,neck spinal lesion,fib cartilage inflammation,symptoms of car-diac depression and dyspnea with or without anxiety.