Background: Lipopolysaccharide (LPS) production through the upregulation of transient receptor potential melastatin 2 (TRPM2)-caused Ca²⁺ influx, cytokine production, intracellular reactive oxygen molecules (iROS), and mitochondrial free reactive oxygen radicals (mROS) generation in microglia induces neurodegenerative diseases. As a synthetic glucocorticoid and anesthetic drug, dexamethasone (DEX) inhibits LPS-induced oxidative stress, cytokine production, and apoptosis in brain cells, including mice microglia (BV-2). We aimed to investigate the protective role of DEX on LPS-induced inflammation, apoptosis, and oxidative cytotoxicity in BV-2 cells by attenuating TRPM2 signaling.

Methods: We induced five primary groups in the cultured BV-2 cells: control, DEX (100 nM for 24 h), LPS (1 μg/mL for 24 h), LPS plus DEX, and LPS plus TRPM2 blocker (N-(p-amylcinnamoyl) anthranilic acid or carvacrol). The cell death, oxidants, and Ca²⁺ analyses of the current study were performed using laser scan confocal microscopy (via fluorescent dyes). A spectrophotometer was used for the lipid peroxidation and antioxidant analyses. An automatic plate reader was used for the apoptosis, cytokine, and caspase analyses. The cell number, debris, and cell viability were determined using a cell counter.

Results: The amount of cell death, apoptosis, oxidants (mROS, iROS, and lipid peroxidation), apoptotic indicators (caspase -3, -8, and -9), cytokines (tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and interleukin-6 (IL-6)), death cell waste (debris), and Ca²⁺ were upregulated by LPS incubation, although their amounts were diminished by the DEX and TRPM2 blocker treatments (p ≤ 0.05). The DEX treatments enhanced the LPS-mediated declines in cell viability, cell number, glutathione, and glutathione peroxidase values (p ≤ 0.05).

Conclusion: The treatment of DEX diminished the LPS-caused inflammatory cytokine, apoptosis, and oxidative stress via TRPM2 attenuation in microglia cells. The DEX may be considered a potential therapeutic way to treat LPS-caused microglia oxidative neuronal injury and neurodegenerative diseases.

Background: Sepsis has been the main cause of mortality in patients in the world. The present study aimed to identify and validate the key genes involved in the development of sepsis.

Methods: Gene expression profiles obtained from GSE35590 were used to screen the differentially expressed genes (DEGs) after endotoxin stimulation. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were carried out to analyze the function of hub genes. The G protein-coupled receptor 84 (GPR84) with the greatest fold change was used as the target gene. The upregulation of GPR84 was validated in THP1, RAW264.7 cells and cecal ligation and puncture (CLP) animal model. Moreover, the predictive ability of GPR84 was evaluated by the area under curve (AUC) in two sepsis datasets.

Results: In total, 267 genes were differentially expressed at three time points. Especially, GPR84 had 39.8, 28.7 and 15.8 folds changes at three time points. The GO and KEGG analysis indicated that GPR84 was mainly correlated with the neutrophil degranulation, immune response-regulating signaling pathway, and immune response-activating signal transduction. Then, the upregulation of GPR84 was validated in the whole blood, THP-1 cells and RAW264.7 cells under lipopolysaccharides (LPS) stimulation. Meanwhile, we also validated the overexpression of GPR84 in sepsis animals and patients. The results indicated that GPR84 may be utilized to predict the risk of sepsis with the AUC of 0.765 (0.649–0.858) in GSE9960 and 0.759 (0.666–0.837) in GSE74224.

Conclusions: This study concluded that upregulated GPR84 may be a target gene for the development of sepsis, and GPR84 could be used to predict the incidence of sepsis.

Clinical Trial Registration: Chinese clinical trial registry: ChiCTR2200064742.

Background: Oxidative stress and inflammation play the central roles in the pathophysiological process of diabetic retinopathy. Our purpose was to elaborate the effect and regulatory mechanism of ferulic acid (FA) in mitigating diabetic retinopathy as well as the functional roles of mitochondrial calcium uniporter (MCU) and NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome and their interplay.

Methods: Human retinal pigment epithelial cells ARPE-19 were pre-treated with 10 mmol/L FA, or transfected with NLPR3 or MCU siRNA or overexpression plasmids. Afterwards, ARPE-19 cells were exposed to 30 mmol/L high glucose for simulating diabetic retinopathy. Intracellular reactive oxygen species (ROS) generation, cytosolic Ca²⁺ level, endoplasmic reticulum (ER) and mitochondrial stress, mitochondrial membrane potential were assayed with 2,7-dichlorofluorescein diacetate (DCFH-DA), Fluo-4 acetoxymethyl ester (Fluo-4 AM), ER-Tracker Red, Seahorse XFe96 Analyzer and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimi-dazolylcarbocyanine iodide (JC-1) staining, respectively. MCU, NLRP3, Interleukin-1beta (IL-1β), toll-like receptor 4 (TLR4), nuclear factor κB (NFκB), AKT serine/threonine kinase1 (AKT1) and phosphorylated-Akt1 (p-AKT1) were measured with western blots or immunohistochemistry.

Results: Both FA pre-treatment and blockage of NLRP3 mitigated apoptosis, intracellular ROS, cytosolic Ca²⁺ level as well as ER and mitochondria stress in hyperglycemia-induced ARPE-19 cells. Additionally, MCU-mediated mitochondrial oxidative stress and NLRP3 inflammasome- and TLR4-dependent AKT/NFκB oxidative and inflammatory signaling were alleviated. Blockage of MCU alleviated hyperglycemia-induced NLRP3 inflammasome activation. Conversely, up-regulation of MCU exacerbated hyperglycemia-induced NLRP3 inflammasome- and TLR4-mediated oxidative and inflammatory signaling, which can be attenuated by FA. Similarly, MCU-mediated mitochondrial oxidative stress was mitigated by FA through NLRP3 inhibition.

Conclusion: Collectively, we present evidence that NLRP3 and MCU are essential for FA alleviating ER- and mitochondria-dependent oxidative stress and inflammation in hyperglycemia-induced ARPE-19 cells. Disturbance of NLRP3 and MCU transcription regulation opens novel avenues to mitigate diabetic retinopathy.

Male infertility is caused by a network of interconnected endogenous mechanisms. Around 50% of male infertility cases are idiopathic. However, oxidative stress (OS) and inflammation have been independently implicated in male infertility. For instance, reduced semen capacity was noted as OS increases the level of reactive oxygen species (ROS) and testicular inflammation increases the number of leukocytes which inhibit its capacity. It is worthy of note that inflammation is intimately connected with OS and together may initiate a vicious cycle with the ability to upend the homeostasis in the testicular system. It has been reported that ROS and reactive nitrogen species (RNS) facilitated by inflammatory cells at the site of inflammation are key factors in the initiation of testicular OS, while proinflammatory gene expressions are also elevated by a signalling pathway triggered by a variety of ROS/RNS. As a result, cellular damage could be exacerbated and male reproductive functions disrupted. Sperm from infertile men have shown higher ROS levels along with increased amounts of proinflammatory proteins and cytokines, thereby supporting the interlink between OS and inflammation. Over the last several decades, a significant number of studies have been conducted seeking to unravel the interplay between OS and inflammation, especially in the testis. This review, therefore, intends to discuss the interdependent interaction between OS and inflammation in testicular dysfunction.

Background: Necrotizing Enterocolitis (NEC) is a critical illness commonly seen in premature and diseased neonates, characterized by mucosal necrosis of the small intestine and colon, which seriously affects the life and health of patients.

Objective: The aim of the research was to investigate the role and mechanism of neutrophils in lung injury in mice with NEC.

Methods: Combinational treatment with formula milk, hypoxia, and lipopolysaccharide (LPS) was performed to establish NEC in 5-day-old C57BL/6J mice. These mice were divided into 4 groups (20 mice in each group) by random number table method: Ctrl group, NEC group, NEC + phosphate-buffered saline (PBS) group, NEC + N-acetyl-L-cysteine (NAC) group. The pathological changes in intestinal and lung tissues were examined through Hematoxylin and Eosin (HE) staining. Lymphocyte antigen 6complex, locus g (Ly6G), neutrophil elastase (NE), myeloperoxidase (MPO) immunohistochemistry (IHC), and flow cytometry were used for qualitative and quantitative analysis of neutrophils in lung tissues respectively. The messenger ribonucleic acid (mRNA) relative expression levels of inflammatory factors in intestinal and lung tissues were detected using Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR). The reactive oxygen species (ROS) release level in neutrophils stimulated by N-formyl-methionyl-leucy1-phenylalanine (fMLP) was detected using an enzyme-labeled instrument. The expression levels of genes in the Kelch-like enoyl-CoA hydratase (ECH)-associated protein 1-nuclear factor erythroid 2-related factor 2 (Keap1-Nrf2) pathway were determined using RT-qPCR.

Results: Compared to the Ctrl group, the intestinal and lung tissues of the mice in the NEC group were significantly damaged (p < 0.0001). However, NAC could significantly relieve the damage (p < 0.0001). Compared to Ctrl group, the mRNA relative expression levels of inflammatory factors and anti-oxidant genes were significantly upregulated (p < 0.05), while the expression levels of anti-ROS genes were significantly downregulated in the NEC group (p < 0.05), and NAC could significantly reverse this result. Mice lung tissue RNA-seq results indicated a significant enrichment in the neutrophil degranulation pathway. The levels of NE, MPO, and ROS released by neutrophils were significantly higher than those in the Ctrl group (p < 0.05). The ROS released by neutrophils is involved in NEC-induced lung injury by regulating the Keap1-Nrf2 pathway, as the inhibition of the release of ROS can alleviate the injury of intestinal and lung tissues.

Conclusions: Neutrophils play an important role in NEC-induced lung injury and NAC has therapeutic potential for NEC-induced lung injury.