Tetramethylpyrazine (TMP) switches energy signalling from the PKCζ-GLUT4-glucose pathway back to the SIRT1-CD36-fatty acid pathway similar to resveratrol to ameliorate cardiac myocyte lipotoxicity

Fatty acid metabolism disorders and potential therapeutic traditional Chinese medicines in cardiovascular diseases

Cardiovascular diseases are currently the primary cause of mortality in the whole world. Growing evidence indicated that the disturbances in cardiac fatty acid metabolism are crucial contributors in the development of cardiovascular diseases. The abnormal cardiac fatty acid metabolism usually leads to energy deficit, oxidative stress, excessive apoptosis, and inflammation. Targeting fatty acid metabolism has been regarded as a novel approach to the treatment of cardiovascular diseases. However, there are currently no specific drugs that regulate fatty acid metabolism to treat cardiovascular diseases. Many traditional Chinese medicines have been widely used to treat cardiovascular diseases in clinics. And modern studies have shown that they exert a cardioprotective effect by regulating the expression of key proteins involved in fatty acid metabolism, such as peroxisome proliferator-activated receptor α and carnitine palmitoyl transferase 1. Hence, we systematically reviewed the relationship between fatty acid metabolism disorders and four types of cardiovascular diseases including heart failure, coronary artery disease, cardiac hypertrophy, and diabetic cardiomyopathy. In addition, 18 extracts and eight monomer components from traditional Chinese medicines showed cardioprotective effects by restoring cardiac fatty acid metabolism. This work aims to provide a reference for the finding of novel cardioprotective agents targeting fatty acid metabolism.

The Contrary Effects of Sirt1 on MCF7 Cells Depend on CD36 Expression Level

BACKGROUND

Breast cancer is one of the most aggressive and pervasive cancers identified in females. Sirt1 and CD36 both exert an essential role toward the oncogenic signaling in breast cancer cells. As reported, the adrenergic signaling could promote the malignancy of breast cancer. This study focuses specifically on the role of Sirt1/CD36 in the proliferation of MCF-7 breast cancer cells and also investigates their response to the α2-adrenergic agonist dexmedetomidine (Dex).

MATERIALS AND METHODS

Expression of Sirt1 and CD36 was measured in breast cancer tissue by immunohistochemistry. We cultured MCF7 cells and treated cells with resveratrol (RSV) or Dex. Western blot analysis was performed to quantify the protein expression levels. The methyl thiazolyl tetrazolium (MTT) assay was applied to detect cell proliferation.

RESULTS

Compared with normal adjacent tissues, Sirt1 increased and CD36 decreased in cancer tissues. RSV, a Sirt1 activator, increased the proliferation of MCF-7 cells at low concentration but exerted cytotoxicity effect at higher concentration. Sirt1 activation increased the expression of CD36 at higher concentration. Dex treatment gradually increased the proliferation of MCF7 cells in a dose-dependent manner and downregulated the expression of Sirt1/CD36. Interestingly, overexpression of Sirt1 via RSV pretreatment could suppress Dex-stimulated proliferation of breast cancer, accompanied with CD36 upregulation.

CONCLUSIONS

though expression of Sirt1 increased in breast cancer progression, overexpression of Sirt1 could inhibit MCF7 proliferation, which may be associated with CD36 upregulation. In addition, the promotion effect of Dex on MCF7 cells, which may be associated with the Sirt1/CD36 inhibition, could be weakened by Sirt1 activation via RSV.