DGKK

Sepsis is an abnormal immune response after infection, wherein the lung is the most susceptible organ to fail, leading to acute lung injury. To overcome the limitations of current therapeutic strategies and develop more specific treatment, the inflammatory process, in which T cell-derived extracellular vesicles (EVs) play a central role, should be explored deeply.

Liquid chromatography-tandem mass spectrometry was performed for serum EV protein profiling. The serum diacylglycerol kinase kappa (DGKK) and endotoxin contents of patients with sepsis-induced lung injury were measured. Apoptosis, oxidative stress, and inflammation in A549 cells, bronchoalveolar lavage fluid, and lung tissues of mice were measured by flow cytometry, biochemical analysis, enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, and western blot.

DGKK, the key regulator of the diacylglycerol (DAG)/protein kinase C (PKC) pathway, exhibited elevated expression in serum EVs of patients with sepsis-induced lung injury and showed strong correlation with sepsis severity and disease progression. DGKK was expressed in CD4⁺ T cells under regulation of the NF-κB pathway and delivered by EVs to target cells, including alveolar epithelial cells. EVs produced by CD4⁺ T lymphocytes exerted toxic effects on A549 cells to induce apoptotic cell death, oxidative cell damage, and inflammation. In mice with sepsis induced by cecal ligation and puncture, EVs derived from CD4⁺ T cells also promoted tissue damage, oxidative stress, and inflammation in the lungs. These toxic effects of T cell-derived EVs were attenuated by the inhibition of PKC and NOX4, the downstream effectors of DGKK and DAG.

This approach established the mechanism that T-cell-derived EVs carrying DGKK triggered alveolar epithelial cell apoptosis, oxidative stress, inflammation, and tissue damage in sepsis-induced lung injury through the DAG/PKC/NOX4 pathway. Thus, T-cell-derived EVs and the elevated distribution of DGKK should be further investigated to develop therapeutic strategies for sepsis-induced lung injury.

Given the known pro-oxidant status of tumour cells, the development of anti-proliferative strategies focuses on products with both anti- and pro-oxidant properties that can enhance antitumour drug cytotoxicity. We used a C. zeylanicum essential oil (CINN-EO) and assessed its effect on a human metastatic melanoma cell line (M14). Human PBMCs and MDMs from healthy donors were used as normal control cells. CINN-EO induced cell growth inhibition, cell cycle perturbation, ROS and Fe(II) increases, and mitochondrial membrane depolarization. To assess whether CINN-EO could affect the stress response, we analysed iron metabolism and stress response gene expression. CINN-EO increased HMOX1, FTH1, SLC7A11, DGKK, and GSR expression but repressed OXR1, SOD3, Tf, and TfR1 expression. HMOX1, Fe(II), and ROS increases are associated with ferroptosis, which can be reversed by SnPPIX, an HMOX1 inhibitor. Indeed, our data demonstrated that SnPPIX significantly attenuated the inhibition of cell proliferation, suggesting that the inhibition of cell proliferation induced by CINN-EO could be related to ferroptosis. Concurrent treatment with CINN-EO enhanced the anti-melanoma effect of two conventional antineoplastic drugs: the mitochondria-targeting tamoxifen and the anti-BRAF dabrafenib. We demonstrate that CINN-EO-mediated induction of an incomplete stress response specifically in cancer cells affects the proliferation of melanoma cells and can enhance drug cytotoxicity.

Nonalcoholic fatty liver disease (NAFLD) as the leading chronic liver disease worldwide causes hepatic fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The aim of this study was to find potential aberrantly methylated and differentially expressed genes in NAFLD of HCC patients with cirrhosis.

DNA methylation data, mRNA expression data, and the corresponding clinical information of HCC were downloaded from the Cancer Genome Atlas (TCGA, tissue sample) database. HCC patients with cirrhosis were divided into two groups according to the presence of NAFLD. The differentially expressed genes (DEGs) and differentially methylated genes (DMGs) were obtained.

By overlapping 79 up-regulated genes and 1020 hypomethylated genes, we obtained 5 hypomethylated-highly expressed genes (Hypo-HGs). By overlapping 365 down-regulated genes and 481 hypermethylated genes, we identified 13 hypermethylated-lowly expressed genes (Hyper-LGs). Survival analysis of these 18 MDEGs indicated that the expression of DGKK and HOXD9 was significantly correlated with the overall survival time of NAFLD patients.

We identified several candidate genes whose expressions were regulated by DNA methylation of NAFLD of HCC with cirrhosis, which may provide a new field in understanding the clinical pathological mechanism of NAFLD of HCC with cirrhosis.