Dynamics and Functional Interplay of Nonhistone Lysine Crotonylome and Ubiquitylome in Vascular Smooth Muscle Cell Phenotypic Remodeling

Protein post-translational modification crotonylation of TXN and GLO1 in artery and vein grafts for coronary artery surgery

A key problem in coronary artery bypass grafting (CABG) is the lower long-term patency of the saphenous vein (SV) compared to internal thoracic artery (ITA). The potential strategies to improve the long-term patency of the vein graft include developing drugs to block unfavorable pathways in the vein and even to change the protein structure of the vein towards arterial structure. It is therefore important to understand the differences of the protein structure between arterial and venous grafts. Using post-translational modification (PTM) proteomics, we systematically investigated differences between ITA and SV with regard to a vascular stenosis-related PTM crotonylation. Crotonylome and PTM crotonylation in paired ITA and SV segments (n = 150) from patients undergoing CABG surgery were performed by proteomics analysis with further validation. To elucidate the underlying mechanisms, we focused on three crotonylated enzymatic proteins with anti-oxidative effects-thioredoxin (TXN), glyoxalase 1 (GLO1), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) - whose crotonylation patterns were systematically investigated. The functional validation was performed using both site-mutation experiments in HEK293 cells and pharmacological inhibitors in ex vivo cultured ITA/SV tissue specimens. Comprehensive crotonyl-proteomics demonstrated 3652 proteins are differentially-expressed and 411 proteins are differentially-crotonylated in ITA/SV segments. In the identified crotonylated proteins, SV demonstrated significantly higher levels compared to ITA. Notably, SV showed higher crotonylation levels on TXN-K3, GLO1-K157, and GAPDH-K61, which were associated with decreased enzymatic activity, elevated methylglyoxal (MGO) accumulation, and increased oxidative stress. Inhibition of CREB-binding protein (CBP) reversed oxidative stress in SV by suppressing crotonylation of the three enzymes. In Hek293 cells, both site-specific and comprehensive crotonylation decreased the activities of TXN/GLO1/GAPDH, which in turn triggered the accumulation of MGO. Overexpression of histone deacetylases HDAC1 and HDAC3 showed the opposite effect, restoring enzyme function. This study is the first to reveal significant differences in PTM crotonylation between human ITA and SV, shedding light on the biological mechanisms underlying the functional disparities between these grafts. These differences impact the enzymatic activity of key proteins involved in oxidative stress, providing insights into the molecular basis of graft performance. Importantly, these findings form a scientific basis for developing specific methods including new anti-oxidative drugs and gene therapy to target on crotonylation in the vein graft in order to improve the long-term graft patency.

Metabolites-mediated posttranslational modifications in cardiac metabolic remodeling: Implications for disease pathology and therapeutic potential

The nonenergy - producing functions of metabolism are attracting increasing attention, as metabolic changes are involved in discrete pathways modulating enzyme activity and gene expression. Substantial evidence suggests that myocardial metabolic remodeling occurring during diabetic cardiomyopathy, heart failure, and cardiac pathological stress (e.g., myocardial ischemia, pressure overload) contributes to the progression of pathology. Within the rewired metabolic network, metabolic intermediates and end-products can directly alter protein function and/or regulate epigenetic modifications by providing acyl groups for posttranslational modifications, thereby affecting the overall cardiac stress response and providing a direct link between cellular metabolism and cardiac pathology. This review provides a comprehensive overview of the functional diversity and mechanistic roles of several types of metabolite-mediated histone and nonhistone acylation, namely O-GlcNAcylation, lactylation, crotonylation, β-hydroxybutyrylation, and succinylation, as well as fatty acid-mediated modifications, in regulating physiological processes and contributing to the progression of heart disease. Furthermore, it explores the potential of these modifications as therapeutic targets for disease intervention.

Lysine crotonylation in disease: mechanisms, biological functions and therapeutic targets

Lysine crotonylation (Kcr), a previously unknown post-translational modification (PTM), plays crucial roles in regulating cellular processes, including gene expression, chromatin remodeling, and cellular metabolism. Kcr is associated with various diseases, including neurodegenerative disorders, cancer, cardiovascular conditions, and metabolic syndromes. Despite advances in identifying crotonylation sites and their regulatory enzymes, the molecular mechanisms by which Kcr influences disease progression remain poorly understood. Understanding the interplay between Kcr and other acylation modifications may reveal opportunities for developing targeted therapies. This review synthesizes current research on Kcr, focusing on its regulatory mechanisms and disease associations, and highlights insights into future exploration in epigenetics and therapeutic interventions.

Lactate Dehydrogenase A Crotonylation and Mono-Ubiquitination Maintains Vascular Smooth Muscle Cell Growth and Migration and Promotes Neointima Hyperplasia

BACKGROUND

Phenotypic plasticity of vascular smooth muscle cells (VSMCs) is believed to be a key factor in neointima hyperplasia, which is the pathological basis of vascular remodeling diseases. LDHA (lactate dehydrogenase A) has been demonstrated to promote the proliferation and migration of VSMCs. However, the mechanism is still unclear.

METHODS AND RESULTS

LDHA ubiquitination and crotonylation in VSMCs were predicted by modified omics and proteomic analysis and were verified by immunoprecipitation. Lysine mutants of LDHA were conducted to determine the specific modified sites. Immunofluorescent staining, cell growth and migration assays, lactate production, immunobloting, adenovirus transduction, LDHA tetramerization, and mitochondrial extraction assays were performed to determine the molecular mechanism. LDHA expression, crotonylation, and ubiquitination in vivo were observed in the carotid arteries of ligation injury mice. We showed that the expression, crotonylation, and mono-ubiquitination of LDHA is upregulated in PDGF-BB (platelet-derived growth factor-BB)-induced proliferative VSMCs and ligation-induced neointima. LDHA is crotonylated at lysine 5 and is mono-ubiquitinated at K76. Crotonylation at lysine 5 activates LDHA through tetramer formation to enhance lactate production and VSMC growth. Mono-ubiquitination at K76 induces the translocation of LDHA into mitochondria, which promotes mitochondria fission and subsequent formation of lamellipodia and podosomes, thereby enhancing VSMC migration and growth. Furthermore, deletion of LDHA K5 crotonylation or K76 mono-ubiquitination decreases ligation-induced neointima formation.

CONCLUSIONS

Our study reveals a novel mechanism that combines VSMC metabolic reprogramming and vascular remodeling. Inhibition of LDHA K5 crotonylation or K76 mono-ubiquitination may be a promising approach for the therapy of vascular remodeling diseases.

Application of crotonylation modification in pan-vascular diseases

Pan-vascular diseases, based on systems biology theory, explore the commonalities and individualities of important target organs such as cardiovascular, cerebrovascular and peripheral blood vessels, starting from the systemic and holistic aspects of vascular diseases. The purpose is to understand the interrelationships and results between them, achieve vascular health or sub-health, and comprehensively improve the physical and mental health of the entire population. Post-translational modification (PTM) is an important part of epigenetics, including phosphorylation, acetylation, ubiquitination, methylation, etc., playing a crucial role in the pan-vascular system. Crotonylation is a novel type of PTM that has made significant progress in the research of pan-vascular related diseases in recent years. Based on the review of previous studies, this article summarises the various regulatory factors of crotonylation, physiological functions and the mechanisms of histone and non-histone crotonylation in regulating pan-vascular related diseases to explore the possibility of precise regulation of crotonylation sites as potential targets for disease treatment and the value of clinical translation.

Function and mechanism of lysine crotonylation in health and disease

Lysine crotonylation is a newly identified posttranslational modification that is different from the widely studied lysine acetylation in structure and function. In the last dozen years, great progress has been made in lysine crotonylation-related studies, and lysine crotonylation is involved in reproduction, development and disease. In this review, we highlight the similarities and differences between lysine crotonylation and lysine acetylation. We also summarize the methods and tools for the detection and prediction of lysine crotonylation. At the same time, we outline the recent advances in understanding the mechanisms of enzymatic and metabolic regulation of lysine crotonylation, as well as the regulating factors that selectively recognize this modification. Particularly, we discussed how dynamic changes in crotonylation status maintain physiological health and result in the development of disease. This review not only points out the new functions of lysine crotonylation but also provides new insights and exciting opportunities for managing various diseases.

Protein lysine crotonylation in cellular processions and disease associations

Protein lysine crotonylation (Kcr) is one conserved form of posttranslational modifications of proteins, which plays an important role in a series of cellular physiological and pathological processes. Lysine ε-amino groups are the primary sites of such modification, resulting in four-carbon planar lysine crotonylation that is structurally and functionally distinct from the acetylation of these residues. High levels of Kcr modifications have been identified on both histone and non-histone proteins. The present review offers an update on the research progression regarding protein Kcr modifications in biomedical contexts and provides a discussion of the mechanisms whereby Kcr modification governs a range of biological processes. In addition, given the importance of protein Kcr modification in disease onset and progression, the potential viability of Kcr regulators as therapeutic targets is elucidated.

Protein crotonylation: Basic research and clinical diseases

Crotonylation is an importantly conserved post-translational modification, which is completely different from acetylation. In recent years, it has been confirmed that crotonylation occurs on histone and non-histone. Crotonylated Histone primarily affects gene expression through transcriptional regulation, while non-histone Crotonylation mainly regulates protein functions including protein activity, localization, and stability, as well as protein-protein interactions. The change in protein expression and function will affect the physiological process of cells and even cause disease. Reviewing previous studies, this article summarizes the mechanisms of histone and non-histone crotonylation in regulating diseases and cellular physiological processes to explore the possibility of precise regulation of crotonylation sites as potential targets for disease treatment.

MTMR7 suppresses the phenotypic switching of vascular smooth muscle cell and vascular intimal hyperplasia after injury via regulating p62/mTORC1-mediated glucose metabolism

BACKGROUND AND AIMS

Myotubularin-related protein 7 (MTMR7) suppresses proliferation in various cell types and is associated with cardiovascular and cerebrovascular diseases. However, whether MTMR7 regulates vascular smooth muscle cell (VSMC) and vascular intimal hyperplasia remains unclear. We explored the role of MTMR7 in phenotypic switching of VSMC and vascular intimal hyperplasia after injury.

METHODS AND RESULTS

MTMR7 expression was significantly downregulated in injured arteries. Compared to wild type (WT) mice, Mtmr7-transgenic (Mtmr7-Tg) mice showed reduced intima/media ratio, decreased percentage of Ki-67-positive cells within neointima, and increased Calponin expression in injured artery. In vitro, upregulating MTMR7 by Len-Mtmr7 transfection inhibited platelet derived growth factor (PDGF)-BB-induced proliferation, migration of VSMC and reversed PDGF-BB-induced decrease in expression of Calponin and SM-MHC. Microarray, single cell sequence, and other bioinformatics analysis revealed that MTMR7 is highly related to glucose metabolism and mammalian target of rapamycin complex 1 (mTORC1). Further experiments confirmed that MTMR7 markedly repressed glycolysis and mTORC1 activity in PDGF-BB-challenged VSMC in vitro. Restoring mTORC1 activity abolished MTMR7-mediated suppression of glycolysis, phenotypic shift in VSMC in vitro and protection against vascular intimal hyperplasia in vivo. Furthermore, upregulating MTMR7 in vitro led to dephosphorylation and dissociation of p62 from mTORC1 in VSMC. External expression of p62 in vitro also abrogated the inhibitory effects of MTMR7 on glycolysis and phenotypic switching in PDGF-BB-stimulated VSMC.

CONCLUSIONS

Our study demonstrates that MTMR7 inhibits injury-induced vascular intimal hyperplasia and phenotypic switching of VSMC. Mechanistically, the beneficial effects of MTMR7 are conducted via suppressing p62/mTORC1-mediated glycolysis.

Role of glycolysis in diabetic atherosclerosis

Diabetes mellitus is a kind of typical metabolic disorder characterized by elevated blood sugar levels. Atherosclerosis (AS) is one of the most common complications of diabetes. Modern lifestyles and trends that promote overconsumption and unhealthy practices have contributed to an increase in the annual incidence of diabetic AS worldwide, which has created a heavy burden on society. Several studies have shown the significant effects of glycolysis-related changes on the occurrence and development of diabetic AS, which may serve as novel thera-peutic targets for diabetic AS in the future. Glycolysis is an important metabolic pathway that generates energy in various cells of the blood vessel wall. In particular, it plays a vital role in the physiological and pathological activities of the three important cells, Endothelial cells, macrophages and vascular smooth muscle cells. There are lots of similar mechanisms underlying diabetic and common AS, the former is more complex. In this article, we describe the role and mechanism underlying glycolysis in diabetic AS, as well as the therapeutic targets, such as trained immunity, microRNAs, gut microbiota, and associated drugs, with the aim to provide some new perspectives and potentially feasible programs for the treatment of diabetic AS in the foreseeable future.

Crotonylation and disease: Current progress and future perspectives

Histone lysine crotonylation was first identified as a new type of post-translational modification in 2011. In recent years, prominent progress has been made in the study of histone and nonhistone crotonylation in reproduction, development, and disease. Although the regulatory enzyme systems and targets of crotonylation partially overlap with those of acetylation, the peculiar CC bond structure of crotonylation suggests that crotonylation may have specific biological functions. In this review, we summarize the latest research progress regarding crotonylation, especially its regulatory factors and relationship with diseases, which suggest further research directions for crotonylation and provide new ideas for developing disease intervention and treatment regimens.