Colorectal cancer (CRC) is a cold tumor with a low response rate to programmed death-ligand 1 (PD-L1) inhibitors, and the regulatory mechanism underlying its expression remains incompletely understood. Lactylation is a novel post-translational modification involved in the regulation of gene transcription and protein function. This study aims to investigate the correlation between lactylation levels and PD-L1 expression in CRC, as well as its clinicopathological significance, so as to provide a novel potential target for immunotherapy.

① The GEPIA2 database was used to analyze the expression correlation between CD274 (encoding PD-L1) and 18 glycolysis genes (including HK1, HK2, and 16 others), lactate dehydrogenase genes (LDHA, LDHB), and lactate transporter genes (SLC16A1, SLC16A4). The TCGA colon adenocarcinoma (COAD) dataset with 453 samples was obtained from the XENA website, and GSEA software was applied to analyze gene ontology＿biological process (GO＿BP) pathway differences between the CD274 high- and low-expression groups. The Kaplan-Meier plotter database was used to evaluate the correlation between CD274 expression and overall survival in 4 consensus molecular subtypes (CMS) of CRC. ② Human CRC cell lines HT29 and SW480 were treated with 10 mmol/L lactic acid (Lac) or 10 mmol/L sodium lactate (Nala) for 24 h, with corresponding blank control groups, or cultured in low-glucose medium (1. 8 g/L glucose) or high-glucose medium (4. 5 g/L glucose). The transcription and translation levels of PD-L1 were detected by RT-qPCR and Western blotting, respectively. In addition, cells were treated with gradient concentrations of sodium lactate or Oxamate (a lactate dehydrogenase inhibitor) to verify the dose-dependent regulation of lactylation on PD-L1 expression. ③ Cancer tissues and paired adjacent non-tumor mucosal tissues were collected from 35 CRC patients (aged 59±11 years, a male-to-female ratio of 2. 2: 1. 0) who underwent surgical treatment at Department of General Surgery of First Affiliated Hospital of Army Medical University between February 2024 and October 2025. Immunohistochemistry (IHC) was performed to detect pan-lactylation (Pan-Kla) and PD-L1 expression, expression levels were evaluated by IHC scoring, and their correlations were analyzed with clinicopathological features.

① GEPIA2 database analysis demonstrated that CD274 expression was significantly positively correlated with glycolysis and lactate dehydrogenase genes (R=0. 14 to 0. 47, P<0. 05), including hexokinase 1 (HK1), hexokinase 3 (HK3), phosphofructokinase platelet type (PFKP), triosephosphate isomerase 1 (TPI1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglucomutase 2 (PGM2), phosphoglucomutase 3 (PGM3), enolase 1 (ENO1), enolase 2 (ENO2), pyruvate kinase M (PKM), lactate dehydrogenase A (LDHA), and lactate dehydrogenase B (LDHB). GSEA revealed that the glycolysis pathway was significantly activated in the CD274 high-expression group, while the oxidative phosphorylation pathway showed no obvious changes. Kaplan-Meier analysis indicated that in CMS Ⅰ (microsatellite unstable) and CMS Ⅳ (mesenchymal) subtypes, the CD274 low-expression group had significantly longer overall survival, whereas no significant correlation was found in CMS Ⅱ (canonical) and CMS Ⅲ (metabolic) subtypes. ② After treatment with Lac and Nala, the mRNA and protein levels of PD-L1 were significantly increased in HT29 and SW480 cells compared with the control group. Cells cultured in low-glucose medium exhibited lower pan-lactylation and PD-L1 expression levels than those cultured in high-glucose medium. Sodium lactate upregulated PD-L1 expression in a dose-dependent manner, and Oxamate treatment reduced PD-L1 expression. ③ Pan-lactylation and PD-L1 scores were significantly higher in CRC tissues than in paired adjacent non-tumor tissues (P<0. 01). A significant positive correlation was observed between them (R²=0. 1959, P=0. 0078). Clinicopathological correlation analysis showed that mucinous adenocarcinoma had significantly higher lactylation scores than non-mucinous adenocarcinoma (P=0. 047).

Lactylation upregulates the transcriptional and translational levels of PD-L1 in colorectal cancer cells and is significantly positively correlated with PD-L1 expression in tumor tissues. The prognostic value of PD-L1 is CMS subtype-specific, and low PD-L1 expression indicates a better prognosis in CMS Ⅰ/Ⅳ patients.

To explore the potential role and underlying mechanism of the functionally uncharacterized gene Gm49394 on regulating β-cell apoptosis under diabetic conditions.

The expression and translational activity of Gm49394 in pancreatic β-cell lines and non-β-cell lines were validated using RNA fluorescence in situ hybridization（RNA-FISH）, quantitative real-time PCR（qPCR）, Western blotting, and immunofluorescence（IF）assay. The β-cell lines（NIT-1/Min6）with Gm49394 overexpression or knockdown were constructed. The proliferation, apoptosis, mitochondrial function, as well as oxidative stress and endoplasmic reticulum stress markers in these β-cell lines under physiological homeostasis or pathological stress conditions, such as high glucose（30 mmol/L）, inflammation（10 ng/mL IFN-γ alone or combined with 10 ng/mL IL-6）, and hydrogen peroxide（100 μmol/L H₂O₂）were detected by flow cytometry and Western blotting.

RNA-FISH and qPCR indicated that Gm49394 was specifically expressed in pancreatic β-cell lines and up-regulated under high glucose or inflammatory stimulation. IF assay and Western blotting showed that Gm49394 had protein-coding activity. Flow cytometry and Western blotting identified that Gm49394 overexpression did not affect β-cell proliferation, but promoted β-cell apoptosis and increased reactive oxygen species（ROS）and mitochondrial superoxide（MitoSOX）levels in β cells under physiological homeostasis or pathological stress conditions（P<0. 05）. Under physiological conditions, Gm49394 knockdown failed to induce significant alterations on β-cell apoptosis, ROS, or MitoSOX levels. Under pathological stress conditions, Gm49394 knockdown significantly suppressed β-cell proliferation, apoptosis, as well as oxidative and endoplasmic reticulum stress（P<0. 05）.

Gm49394 may promote β-cell apoptosis via oxidative stress and endoplasmic reticulum stress.

To compare and analyze the differences in CD8⁺ naive, effector, memory, exhausted and regulatory T cells in order to investigate the impact of gender on the differentiation fate of CD8⁺ T cells in the context of type 1 diabetes (T1D) based on female and male non-obese diabetic (NOD) mice and healthy Institute for Cancer Research (ICR) mice.

The frequencies and phenotypes of CD8⁺ T cell differentiation subsets including naive T cells (T_N), central memory T cells (T_CM), effector T cells (T_EFF), effector precursor T cells (T_EP), exhausted T cells (T_EX), precursor exhausted T cells (T_PEX) and regulatory T cells (Tregs) in the spleen, pancreatic draining lymph nodes (pLN) and pancreas infiltrating lymphocytes (PIL) of male and female NOD mice were detected by flow cytometry.

The frequencies of IFN-γ⁺, CD107a⁺ and CCL5⁺ CD8⁺ T_EFF in pLN and PIL of female NOD mice were significantly higher than those of male NOD mice. However, the frequencies of CD8⁺ T_N, CD8⁺ T_CM, CD8⁺ T_EX, CD8⁺ T_PEX and CD122⁺CD8⁺ Tregs subsets in the spleen were significantly decreased. While there were no significant differences in the above CD8⁺ T cell subsets except CD8⁺ Tregs between female and male ICR mice.

Androgen may inhibit the differentiation of memory T cells into effector T cells and promote the exhaustion of effector T cells, leading to the difference in morbidity between the male and female mice.