An optimized desuccinylase activity assay reveals a difference in desuccinylation activity between proliferative and differentiated cells

Dysregulation of protein succinylation and disease development

As a novel post-translational modification of proteins, succinylation is widely present in both prokaryotes and eukaryotes. By regulating protein translocation and activity, particularly involved in regulation of gene expression, succinylation actively participates in diverse biological processes such as cell proliferation, differentiation and metabolism. Dysregulation of succinylation is closely related to many diseases. Consequently, it has increasingly attracted attention from basic and clinical researchers. For a thorough understanding of succinylation dysregulation and its implications for disease development, such as inflammation, tumors, cardiovascular and neurological diseases, this paper provides a comprehensive review of the research progress on abnormal succinylation. This understanding of association of dysregulation of succinylation with pathological processes will provide valuable directions for disease prevention/treatment strategies as well as drug development.

Sirtuin 5-Mediated Lysine Desuccinylation Protects Mitochondrial Metabolism Following Subarachnoid Hemorrhage in Mice

BACKGROUND AND PURPOSE

Sirt5 (Sirtuin 5) desuccinylates multiple metabolic enzymes and plays an important role in maintaining energy homeostasis. The goal of this study was to determine whether Sirt5-mediated desuccinylation restores the energy metabolism and protects brain against subarachnoid hemorrhage (SAH).

METHODS

Male C57BL/6 or Sirt5^-/- mice were used. The endovascular perforation SAH model was applied. Protein lysine succinylation in the brain cortex was examined using liquid chromatography-tandem mass spectrometry analysis. The brain metabolism was evaluated by measurement of brain pH as well as ATP and reactive oxygen species level. Neuronal cell death and neurobehavioral deficits were assessed 24 hours after SAH. The expression and desuccinylation activity of Sirt5, lysine succinylation of citrate synthase and ATP synthase subunits were investigated by Western blot, immunohistochemistry, and ELISA in SAH mice and patients. Furthermore, the benefits of resveratrol-mediated Sirt5 activation were investigated.

RESULTS

A total of 211 lysine succinylation sites were differentially expressed on 170 proteins in mice brain after SAH. Thirty-nine percent of these succinylated proteins were localized in mitochondria and they are related to energy metabolism. SAH caused a decrease of Sirt5 expression and succinylated citrate synthase as well as the subunits of ATP synthase, subsequently lowered brain pH, reduced ATP and increased reactive oxygen species production, leading to neuronal cell death, and neurological deficits. Knockdown of Sirt5 aggravated SAH-induced effects, mentioned above. Administration of resveratrol resulted in activation of Sirt5. The activation was accompanied both with restoration of the mitochondrial metabolism and alleviation of early brain injury as well as with desuccinylating citrate synthase and ATP synthase.

CONCLUSIONS

Protein lysine succinylation is a biochemical hallmark of metabolic crisis after SAH, and disruption of lysine succinylation through activation of Sirt5 might be a promising therapeutic strategy for the treatment of SAH.

The Pleiotropic Function of Human Sirtuins as Modulators of Metabolic Pathways and Viral Infections

Sirtuins (SIRTs) are nicotinamide adenine dinucleotide-dependent histone deacetylases that incorporate complex functions in the mechanisms of cell physiology. Mammals have seven distinct members of the SIRT family (SIRT1-7), which play an important role in a well-maintained network of metabolic pathways that control and adapt the cell to the environment, energy availability and cellular stress. Until recently, very few studies investigated the role of SIRTs in modulating viral infection and progeny. Recent studies have demonstrated that SIRT1 and SIRT2 are promising antiviral targets because of their specific connection to numerous metabolic and regulatory processes affected during infection. In the present review, we summarize some of the recent progress in SIRTs biochemistry and their emerging function as antiviral targets. We also discuss the potential of natural polyphenol-based SIRT modulators to control their functional roles in several diseases including viral infections.