Glucose-derived posttranslational modification in cardiovascular disease

Insights into the post-translational modifications in heart failure

Heart failure (HF), as the terminal manifestation of multiple cardiovascular diseases, causes a huge socioeconomic burden worldwide. Despite the advances in drugs and medical-assisted devices, the prognosis of HF remains poor. HF is well-accepted as a myriad of subcellular dys-synchrony related to detrimental structural and functional remodelling of cardiac components, including cardiomyocytes, fibroblasts, endothelial cells and macrophages. Through the covalent chemical process, post-translational modifications (PTMs) can coordinate protein functions, such as re-localizing cellular proteins, marking proteins for degradation, inducing interactions with other proteins and tuning enzyme activities, to participate in the progress of HF. Phosphorylation, acetylation, and ubiquitination predominate in the currently reported PTMs. In addition, advanced HF is commonly accompanied by metabolic remodelling including enhanced glycolysis. Thus, glycosylation induced by disturbed energy supply is also important. In this review, firstly, we addressed the main types of HF. Then, considering that PTMs are associated with subcellular locations, we summarized the leading regulation mechanisms in organelles of distinctive cell types of different types of HF, respectively. Subsequently, we outlined the aforementioned four PTMs of key proteins and signaling sites in HF. Finally, we discussed the perspectives of PTMs for potential therapeutic targets in HF.

Role of STIM1 in the Regulation of Cardiac Energy Substrate Preference

The heart requires a variety of energy substrates to maintain proper contractile function. Glucose and long-chain fatty acids (FA) are the major cardiac metabolic substrates under physiological conditions. Upon stress, a shift of cardiac substrate preference toward either glucose or FA is associated with cardiac diseases. For example, in pressure-overloaded hypertrophic hearts, there is a long-lasting substrate shift toward glucose, while in hearts with diabetic cardiomyopathy, the fuel is switched toward FA. Stromal interaction molecule 1 (STIM1), a well-established calcium (Ca2+) sensor of endoplasmic reticulum (ER) Ca2+ store, is increasingly recognized as a critical player in mediating both cardiac hypertrophy and diabetic cardiomyopathy. However, the cause-effect relationship between STIM1 and glucose/FA metabolism and the possible mechanisms by which STIM1 is involved in these cardiac metabolic diseases are poorly understood. In this review, we first discussed STIM1-dependent signaling in cardiomyocytes and metabolic changes in cardiac hypertrophy and diabetic cardiomyopathy. Second, we provided examples of the involvement of STIM1 in energy metabolism to discuss the emerging role of STIM1 in the regulation of energy substrate preference in metabolic cardiac diseases and speculated the corresponding underlying molecular mechanisms of the crosstalk between STIM1 and cardiac energy substrate preference. Finally, we briefly discussed and presented future perspectives on the possibility of targeting STIM1 to rescue cardiac metabolic diseases. Taken together, STIM1 emerges as a key player in regulating cardiac energy substrate preference, and revealing the underlying molecular mechanisms by which STIM1 mediates cardiac energy metabolism could be helpful to find novel targets to prevent or treat cardiac metabolic diseases.

Evaluating the role of cytokinesis-block micronucleus assay as a biomarker for oxidative stress-inducing DNA damage in type 2 diabetes mellitus patients

Background

Type 2 Diabetes Miletus (T2DM) is a common metabolic and lifestyle disorder leading to increased oxidative stress and DNA damage. The present study aims to evaluate the feasibility of utilizing the cytokinesis-block micronucleus assay (CBMN) as a biomarker for assessing the DNA damage induced due to variations in oxidative stress.

Methodology

The study group includes diabetic (n = 50) and non-diabetic (n = 50) subjects. The assays for the diabetes-like fasting blood sugar, postprandial glucose and hemoglobin A1c (HbA1c), lipid profiling, and serum ferritin level along with c-reactive protein (CRP) were applied. Further, the CBMN assay was performed to evaluate the micronuclei present in the lymphocytes of control and T2DM groups.

Results

Significant imbalance in the glycaemic index, dyslipidemia, increased ferritin levels, and CRP levels, with a significant increase of micronucleus frequency, was found in T2DM patients compared with the control group. Results suggest a trend of positive correlation between HbA1c and the micronuclei, indicating the assay’s potential importance as a biomarker for T2DM-induced risk assessment.

Conclusion

From the observed results, it can be suggested that the CBMN assay could be used to assess the risk of oxidative stress-induced DNA damage in high glycaemic index diabetic patients.