Lactylation: The emerging frontier in post-translational modification.

Lactate, a metabolic byproduct, has gained recognition as a highly influential signaling molecule. Lactylation, an emerging form of post-translational modification derived from lactate, plays a crucial role in numerous cellular processes such as inflammation, embryonic development, tumor proliferation, and metabolism. However, the precise molecular mechanisms through which lactylation governs these biological functions in both physiological and pathological contexts remain elusive. Hence, it is imperative to provide a comprehensive overview of lactylation in order to elucidate its significance in biological processes and establish a foundation for forthcoming investigations. This review aims to succinctly outline the process of lactylation modification and the characterization of protein lactylation across diverse organisms. Additionally, A summary of the regulatory mechanisms of lactylation in cellular processes and specific diseases is presented. Finally, this review concludes by delineating existing research gaps in lactylation and proposing primary directions for future investigations.

Maternal betaine supplementation ameliorates fatty liver disease in offspring mice by inhibiting hepatic NLRP3 inflammasome activation.

BACKGROUND/OBJECTIVES: Previous research has shown maternal betaine supplementation alleviates fetal-derived hepatic steatosis. Therefore, this study examined the anti-inflammatory effect of maternal betaine intake in offspring mice and its mechanism. MATERIALS/METHODS: Female C57BL/6J mice and their offspring were randomly divided into 3 groups according to the treatment received during gestation and lactation: control diet (CD), fatty liver disease (FLD), and fatty liver disease + 1% betaine (FLD-BET). The FLD group was given a high-fat diet and streptozotocin (HFD + STZ), and the FLD-BET group was treated with HFD + STZ + 1% betaine. After weaning, the offspring mice were given a normal diet for 5 weeks and then dissected to measure the relevant indexes. RESULTS: Compared to the CD group, the offspring mice in the FLD group revealed obvious hepatic steatosis and increased serum levels of alanine aminotransferase, interleukin (IL)-6, and tumor necrosis factor (TNF)-α; maternal betaine supplementation reversed these changes. The hepatic mRNA expression levels of IL-6, IL-18, and Caspase-1 were significantly higher in the FLD group than in the CD group. Maternal betaine supplementation reduced the expression of IL-1ß, IL-6, IL-18, and apoptosis-associated speck-like protein containing C-terminal caspase recruitment domain (ASC). Maternal betaine supplementation also reversed the increasing protein expressions of nitric oxide dioxygenase-like receptor family pyrin domain containing 3 (NLRP3), ASC, Caspase-1, IL-1ß, and IL-18 in offspring mice exposed to HFD + STZ. Maternal betaine supplementation decreased the homocysteine (Hcy) and s-adenosine homocysteine (SAH) levels significantly in the livers. Furthermore, the hepatic Hcy concentrations showed significant inverse relationships with the mRNA expression of TNF-α, NLRP3, ASC, and IL-18. The hepatic SAH concentration was inversely associated with the IL-1ß mRNA expression. CONCLUSIONS: The lipotropic and anti-inflammatory effect of maternal betaine supplementation may be associated with the inhibition of NLRP3 inflammasome in the livers of the offspring mice.

Deciphering the Biological Effects of Radiotherapy in Cancer Cells.

Radiotherapy remains an effective conventional method of treatment for patients with cancer. However, the clinical efficacy of radiotherapy is compromised by the development of radioresistance of the tumor cells during the treatment. Consequently, there is need for a comprehensive understanding of the regulatory mechanisms of tumor cells in response to radiation to improve radiotherapy efficacy. The current study aims to highlight new developments that illustrate various forms of cancer cell death after exposure to radiation. A summary of the cellular pathways and important target proteins that are responsible for tumor radioresistance and metastasis is also provided. Further, the study outlines several mechanistic descriptions of the interaction between ionizing radiation and the host immune system. Therefore, the current review provides a reference for future research studies on the biological effects of new radiotherapy technologies, such as ultra-high-dose-rate (FLASH) radiotherapy, proton therapy, and heavy-ion therapy.

Association of Hepatic Global DNA Methylation and Serum One-Carbon Metabolites with Histological Severity in Patients with NAFLD.

OBJECTIVE: Clinical relevance of global DNA methylation and one-carbon metabolite levels with histological severity remains uncertain in patients with nonalcoholic fatty liver disease (NAFLD). This study aimed to evaluate hepatic global DNA methylation and serum one-carbon metabolite concentrations in patients with NAFLD and the possible associations of these parameters with liver histology. METHODS: Liver biopsies from 18 control participants and 47 patients with NAFLD were evaluated. RESULTS: The hepatic global DNA methylation level was significantly lower in the NAFLD group than in the control group among participants with overweight. Participants with moderate inflammation and mild fibrosis had significantly lower levels of global DNA methylation than those without these characteristics. Participants with borderline nonalcoholic steatohepatitis had significantly lower global DNA methylation levels than controls. The hepatic global DNA methylation level tended to decrease with the increasing hepatic inflammation grade and disease progression. The NAFLD group had a significantly higher serum homocysteine concentration than the control group among participants with overweight. This level tended to increase with increasing hepatic steatosis grade and disease progression. CONCLUSIONS: Patients with NAFLD exhibited lower hepatic levels of global DNA methylation and elevated serum homocysteine concentrations, which are associated with the histological severity of NAFLD.

Low Levels of Serum ß-Carotene and ß-Carotene/Retinol Ratio Are Associated with Histological Severity in Nonalcoholic Fatty Liver Disease Patients.

ß-Carotene has been reported to alleviate hepatic steatosis (SS), inflammation, and fibrosis in vivo and vitro studies. However, the clinical relevance of serum ß-carotene and ß-carotene-to-retinol (SC/SR) ratio with histological severity in nonalcoholic fatty liver disease (NAFLD) patients is unknown. This case-control study enrolled 24 control subjects and 62 NAFLD patients. Liver biopsies were collected and histological characteristics were assessed. Information with regard to demographic, anthropometric and dietary intake was assessed by face-to-face interviews with questionnaire. Serum ß-carotene and retinol concentrations were determined by the HPLC method. Serum ß-carotene and SC/SR levels in NAFLD patients were significantly lower than these in controls (0.23 ± 0.01 vs. 0.35 ± 0.04 µmol/L, 0.38 ± 0.03 vs. 0.84 ± 0.10). Compared with individuals without SS, both ß-carotene and SC/SR levels were significantly decreased in those with moderate SS (0.34 ± 0.03 vs. 0.21 ± 0.02 µmol/L, 0.76 ± 0.09 vs. 0.37 ± 0.05). Subjects with mild inflammation had a significantly lower ß-carotene and SC/SR levels than those without inflammation (0.23 ± 0.01 vs. 0.33 ± 0.04 µmol/L, 0.77 ± 0.09 vs. 0.38 ± 0.03). Serum SC/SR was significantly lower in patients with mild fibrosis than those without fibrosis (0.45 [0.27-0.83] vs. 0.34 [0.26-0.51]). According to the NAFLD Activity Scoring score, both ß-carotene and SC/SR gradually decreased with disease progression from normal liver, simple SS to steatohepatitis borderline (ptrend ≤ 0.001). These results show that NAFLD patients have lower circulating ß-carotene concentration and SC/SR ratio, which are associated with the histological severity of NAFLD.