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The master DNA damage repair histone protein, H2AX, is essential for orchestrating the recruitment of downstream mediator and effector proteins at damaged chromatin. The phosphorylation of H2AX at S139, γH2AX, is well-studied for its DNA repair function. However, the extended C-terminal tail is not characterized. Here, we define the minimal motif on H2AX for the canonical function in activating the MDC1-RNF8-RNF168 phosphorylation-ubiquitination pathway that is important for recruiting repair proteins, such as 53BP1 and BRCA1. Interestingly, H2AX recruits 53BP1 independently from the MDC1-RNF8-RNF168 pathway through its evolved C-terminal linker region with S139 phosphorylation. Mechanistically, 53BP1 recruitment to damaged chromatin is mediated by the interaction between the H2AX C-terminal tail and the 53BP1 Oligomerization-Tudor domains. Moreover, γH2AX-linker mediated 53BP1 recruitment leads to camptothecin resistance in H2AX knockout cells. Overall, our study uncovers an evolved mechanism within the H2AX C-terminal tail for regulating DNA repair proteins at damaged chromatin.

Objective: Response surface methodology was used to optimize the extraction process of steroidal glycosides from Cynanchum auriculatum Royle ex Wight by complex enzymatic method, and its effects on alcohol dehydrogenase activity and human hepatoma cell HepG2 were analyzed. Methods: Four experimental factors; enzymolysis duration, temperature, compound enzyme dose and pH were used as responses to a single-factor experiment of the Response Surface Methodology on the steroidal glycoside yields, using perennial C. auriculatum as the target material. The alcohol-induced hepatocyte damage model of HepG2 was used to investigate the contents of ALT, LDH, and GSH and changes in cell shape. Results: The results show that the optimum extraction conditions of steroidal glycoside enzyme were obtained at an enzymolysis duration of 100 min, a temperature of 46 ℃, enzyme dose of 1.30% and pH of 5.0. Consequently, the actual extraction rate of （2.80±0.04）% was achieved using the optimized process conditions, which was close to the expected value. Compared with the model group, it significantly suppresses the growth of ALT and LDH while increasing the amount of intracellular GSH, and the cell damage was restored. Conclusion: The compound enzyme method can effectively extract the steroidal glycosides of Cynanchum auriculatum Royle ex Wight; steroidal glycosides of C. auriculatum have hepatoprotective effect.

Introduction: Atherosclerotic complications represent the leading cause of cardiovascular mortality globally. Dysfunction of endothelial cells (ECs) often initiates the pathological events in atherosclerosis. Objectives: In this study, we sought to investigate the transcriptional profile of atherosclerotic aortae, identify novel regulator in dysfunctional ECs and hence provide mechanistic insights into atherosclerotic progression. Methods: We applied single-cell RNA sequencing (scRNA-seq) on aortic cells from Western diet-fed apolipoprotein E-deficient (ApoE−/−) mice to explore the transcriptional landscape and heterogeneity of dysfunctional ECs. In vivo validation of SOX4 upregulation in ECs were performed in atherosclerotic tissues, including mouse aortic tissues, human coronary arteries, and human renal arteries. Single-cell analysis on human aortic aneurysmal tissue was also performed. Downstream vascular abnormalities induced by EC-specific SOX4 overexpression, and upstream modulators of SOX4 were revealed by biochemical assays, immunostaining, and wire myography. Effects of shear stress on endothelial SOX4 expression was investigated by in vitro hemodynamic study. Results: Among the compendium of aortic cells, mesenchymal markers in ECs were significantly enriched. Two EC subsets were subsequently distinguished, as the ‘endothelial-like’ and ‘mesenchymal-like’ subsets. Conventional assays consistently identified SOX4 as a novel atherosclerotic marker in mouse and different human arteries, additional to a cancer marker. EC-specific SOX4 overexpression promoted atherogenesis and endothelial-to-mesenchymal transition (EndoMT). Importantly, hyperlipidemia-associated cytokines and oscillatory blood flow upregulated, whereas the anti-diabetic drug metformin pharmacologically suppressed SOX4 level in ECs. Conclusion: Our study unravels SOX4 as a novel phenotypic regulator during endothelial dysfunction, which exacerbates atherogenesis. Our study also pinpoints hyperlipidemia-associated cytokines and oscillatory blood flow as endogenous SOX4 inducers, providing more therapeutic insights against atherosclerotic diseases.

Background: Seven-carbon sugars, which rarely exist in nature, are the key constitutional unit of septacidin and hygromycin B in bacteria. These sugars exhibit a potential therapeutic effect for hypoglycaemia and cancer and serve as building blocks for the synthesis of C-glycosides and novel antibiotics. However, chemical and enzymatic approaches for the synthesis of seven-carbon sugars have faced challenges, such as complex reaction steps, low overall yields and high-cost feedstock, limiting their industrial-scale production. Results: In this work, we propose a strain engineering approach for synthesising sedoheptulose using glucose as sole feedstock. The gene pfkA encoding 6-phosphofructokinase in Corynebacterium glutamicum was inactivated to direct the carbon flux towards the pentose phosphate pathway in the cellular metabolic network. This genetic modification successfully enabled the synthesis of sedoheptulose from glucose. Additionally, we identified key enzymes responsible for product formation through transcriptome analysis, and their corresponding genes were overexpressed, resulting in a further 20% increase in sedoheptulose production. Conclusion: We achieved a sedoheptulose concentration of 24 g/L with a yield of 0.4 g/g glucose in a 1 L fermenter, marking the highest value up to date. The produced sedoheptulose could further function as feedstock for synthesising structural seven-carbon sugars through coupling with enzymatic isomerisation, epimerisation and reduction reactions. [ABSTRACT FROM AUTHOR]

Tricuspid regurgitation (TR) may occur late after left-sided valve surgery (LSVS). Isolated tricuspid regurgitation after left-sided valve surgery (iTR-LSVS) refers to isolated TR without significant lesions in the mitral and/or aortic position late after mitral and/or aortic replacement or repair. Severe TR has a negative impact on long-term prognosis and requires surgical or transcatheter treatment. However, there is no clear recommendation on when and how intervention should be performed for patients with iTR-LSVS in the current guidelines for the management of valvular heart disease. The historically high operative mortality may be reduced by current minimally invasive techniques and transcatheter therapy. To further understand iTR-LSVS, standardize the treatment, improve the prognosis, and promote the collaboration, the Chinese Minimally Invasive Cardiovascular Surgery Committee (CMICS) wrote this expert consensus on the management of iTR-LSVS from the aspects of etiology, preoperative evaluation, indications for intervention, surgical treatment, transcatheter therapy, and postoperative management.

Purpose: We investigated the relationship between body mass index (BMI), radiological body composition, and survival outcomes in patients with metastatic renal cell carcinoma (mRCC) underwent first-line immune checkpoint inhibitor (ICI)-based therapy. Methods: Analyzing data from 102 patients treated between November 2019 and March 2023, pre-treatment computed tomography (CT) scans assessed fat and muscle areas. BMI and body composition indices were examined, including skeletal muscle index, subcutaneous fat index (SFI), visceral fat index, and total fat index. Kaplan–Meier curves and Log rank tests compared progression-free survival (PFS) and overall survival (OS), while multivariable Cox proportional regression analysis was performed to identify the variables significantly associated with survival outcomes. Results: 54 patients (52.9%) experienced disease progression, and 26 (25.5%) died during a median follow-up of 17.4 months. High SFI was significantly associated with improved OS (p = 0.018) but not PFS (p = 0.090). Multivariable analysis confirmed the positive impact of high SFI on OS (adjusted HR: 0.37, p = 0.029) and suggested a trend towards improved PFS (adjusted HR: 0.61, p = 0.088). Notably, in the ipilimumab + nivolumab subgroup, high SFI significantly correlated with both PFS and OS (p = 0.047 and p = 0.012, respectively). Conclusion: High SFI predicts favorable OS in patients with mRCC receiving first-line ICI-based therapy, especially patients treated with ipilimumab + nivolumab displayed a significant association between high SFI and favorable PFS and OS. [ABSTRACT FROM AUTHOR]