MEHP induces pyroptosis and autophagy alternation by cathepsin B activation in INS-1 cells

Quercetin alleviates DEHP exposure-induced pyroptosis and cytokine expression changes in grass carp L8824 cell line by inhibiting ROS/MAPK/NF-κB pathway

Bis(2-ethylhexyl) phthalate (DEHP) is not only a widely used plasticizer but also a common endocrine disruptor that frequently lingers in water, posing a threat to the health of aquatic organisms. Quercetin (Que) is a common flavonol found in the plant kingdom known for its antioxidant, anti-inflammatory, and immunomodulatory effects. However, it is still unclear whether DEHP can cause pyroptosis and affect the expression of cytokines of grass carp L8824 cells and whether Que has antagonistic effect in this process. In our study, grass carp L8824 cells were treated into four groups after 24 h, namely NC group, DEHP group (1000 μM DEHP), Que group (5 μM Que), and DEHP + Que group (1000 μM DEHP + 5 μM Que). Our results indicate a significant increase in the level of ROS in L8824 cells after exposure to DEHP. DEHP upregulated oxidative stress markers (H2O2 and MDA) and downregulated antioxidant markers (CAT, GSH, SOD, and T-AOC). DEHP also upregulated MAPK and NF-κB signal pathway-related proteins and mRNA expressions (p-p38, p-JNK, p-EPK, and p65). As for cell pyroptosis and its related pathways, DEHP upregulated pyroptosis-related protein and mRNA expressions (GSDMD, IL-1β, NLRP3, Caspase-1, LDH, pro-IL-18, IL-18, and ASC). Finally, DEHP can up-regulated cytokines (IL-6 and TNF-α) expression, down-regulated cytokines (IL-2 and IFN-γ) expression, and antimicrobial peptides (β-defensin, LEAP2, and HEPC). The co-treatment of L8824 cells with DEHP and Que inhibited the activation of the ROS/MAPK/NF-κB axis, alleviated pyroptosis, and restored expression of immune-related indicators. Finally, NAC was applied to reverse intervention of oxidative stress. In summary, Que inhibited DEHP-induced pyroptosis and the influence on cytokine and antimicrobial peptide expression in L8824 cells by regulating the ROS/MAPK/NF-κB pathway. Our results demonstrate the threat to fish health from DEHP exposure and confirmed the harm of DEHP to the aquatic ecological environment and the detoxification effect of Que to DEHP, which provides a theoretical basis for environmental toxicology.

Elaidic acid induced hepatocyte pyroptosis via autophagy-CTSB-NLRP3 pathway

Elaidic acid (EA, C18:1 trans) is a kind of principal Trans fatty acid (TFA) and is widely found in processed food. Pyroptosis is a form of programmed cell death, distinct from apoptosis and traditional necrosis. Excessive pyroptosis could induce body injury and serious inflammation. However, the effect of EA on pyroptosis has not been reported. In the study, we found that EA exposure caused liver damage and hepatocyte pyroptosis by testing GSDMD-N, Caspase 1, IL-18, and IL-1β in mice and HepG2 cells. Further exploring the mechanisms, we found that EA-induced pyroptosis depended on Cathepsin B (CTSB)-mediated NLRP3 inflammasome activation. Cell autophagy was closely related to lysosomes. Our study revealed that EA promoted hepatocyte autophagy, and activated autophagy induced lysosomal membrane permeabilization (LMP) and CTSB leakage. Inhibition of autophagy by 3-MA mitigated the CTSB leak, reduced the activation of the NLRP3 inflammasome, and then attenuated the EA-induced pyroptosis. In summary, these results indicated that EA induced hepatocyte pyroptosis via autophagy-CTSB-NLRP3 inflammasome pathway. The study revealed new insights into the toxicity mechanism of EA.

The Hidden Threat: Endocrine Disruptors and Their Impact on Insulin Resistance

The association between Insulin resistance, a global health issue, and endocrine disruptors (EDCs), chemicals interfering with the endocrine system, has sparked concern in the scientific community. This article provides a comprehensive review of the existing literature regarding the intricate relationship between EDCs and insulin resistance. Phthalates, commonly found in consumer products, are well-established EDCs with documented effects on insulin-signaling pathways and metabolic processes. Epidemiological studies have connected phthalate exposure to an increased risk of type 2 diabetes mellitus (T2DM). Perfluoroalkyl substances (PFAS), persistent synthetic compounds, have shown inconsistent associations with T2DM in epidemiological research. However, studies suggest that PFAS may influence insulin resistance and overall metabolic health, with varying effects depending on specific PFAS molecules and study populations. Bisphenol A (BPA), found in plastics and resins, has emerged as a concern for glucose regulation and insulin resistance. Research has linked BPA exposure to T2DM, altered insulin release, obesity, and changes in the mass and function of insulin-secreting β-cells. Triclosan, an antibacterial agent in personal care products, exhibits gender-specific associations with T2DM risk. It may impact gut microbiota, thyroid hormones, obesity, and inflammation, raising concerns about its effects on metabolic health. Furthermore, environmental EDCs like polycyclic aromatic hydrocarbons, pesticides, and heavy metals have demonstrated associations with T2DM, insulin resistance, hypertension, and obesity. Occupational exposure to specific pesticides and heavy metals has been linked to metabolic abnormalities.

Combined exposure to benzo(a)pyrene and dibutyl phthalate aggravates pro-inflammatory macrophage polarization in spleen via pyroptosis involving cathepsin B

Humans are often simultaneously exposed to benzo(a)pyrene (BaP) and dibutyl phthalate (DBP) through consumption of food and water. Yet, direct evidence of the link between BaP and DBP co-exposure and the risk of splenic injury is lacking. In the present study, we established the rats and primary splenic macrophages models to evaluate the effects of BaP or/and DBP exposure on spleen and underlying mechanisms. Compared to the single exposure or control groups, the co-exposure group showed more severe spleen damage and higher production of pro-inflammatory cytokines. Co-exposure to BaP and DBP resulted in a 1.79-fold, 2.11-fold and 1.9-fold increase in the M1 macrophage markers iNOS, NLRP3 (pyroptosis marker protein) and cathepsin B (CTSB), respectively, and a 0.8-fold decrease in the M2 macrophage marker Arg1 in vivo. The more prominent effects in perturbation of imbalance in M1/M2 polarization (iNOS, 2.25-fold; Arg1, 0.55-fold), pyroptosis (NLRP3, 1.43-fold), and excess CTSB (1.07-fold) in macrophages caused by BaP and DBP co-exposure in vitro were also found. Notably, MCC950 (the NLRP3-specific inhibitor) treatment attenuated the pro-inflammatory macrophage polarization and following pro-inflammatory cytokine production triggered by BaP and DBP co-exposure. Furthermore, CA-074Me (the CTSB-specific inhibitor) suppressed the macrophages pyroptosis, pro-inflammatory macrophage polarization, and secretion of pro-inflammatory cytokine induced by BaP and DBP co-exposure. In conclusion, this study indicates co-exposure to BaP and DBP poses a higher risk of spleen injury. Pro-inflammatory macrophage polarization regulated by pyroptosis involving CTSB underlies the spleen injury caused by BaP and DBP co-exposure.

Epigallocatechin gallate alleviates mono-2-ethylhexyl phthalate-induced male germ cell pyroptosis by inhibiting the ROS/mTOR/NLRP3 pathway

Mono-2-ethylhexyl phthalate (MEHP) exposure is known to induce severe testicular injury via reactive oxygen species (ROS). However, few effective treatments are available for the precise treatment of MEHP-induced germ cell damage. Epigallocatechin gallate (EGCG), one of the major polyphenols in green tea, has potential antioxidant activity and can alleviate many diseases induced by oxidative stress. This study explored whether EGCG protects germ cells from MEHP-induced oxidative stress damage. Cells were treated with 400 μM MEHP and 60 μM EGCG for 24 h. EGCG reduced MEHP-induced ROS overgeneration in the spermatogonial cell line GC-1 and spermatocyte cell line GC-2. Western blotting and immunofluorescence showed that the MEHP+EGCG group exhibited lower nuclear factor (erythroid-derived 2)-like 2 (NRF2), heme oxygenase (decycling) 1 (HO-1), and superoxide dismutase (SOD) expression than the MEHP group. Moreover, activation of the mammalian target of rapamycin (mTOR) pathway was decreased. The expression of key factors of pyroptosis was downregulated, and interleukin-10 (IL-10) expression was reduced. Additionally, apoptosis was inhibited by EGCG. The findings indicate that EGCG protects against MEHP-induced germ cell pyroptosis by scavenging ROS, suppressing the mTOR pathway, and inhibiting pyroptosis. EGCG may thus be a potential treatment for MEHP-related spermatogenic dysfunction.

Endocrine disruptors in plastics alter β-cell physiology and increase the risk of diabetes mellitus

Plastic pollution breaks a planetary boundary threatening wildlife and humans through its physical and chemical effects. Of the latter, the release of endocrine disrupting chemicals (EDCs) has consequences on the prevalence of human diseases related to the endocrine system. Bisphenols (BPs) and phthalates are two groups of EDCs commonly found in plastics that migrate into the environment and make low-dose human exposure ubiquitous. Here we review epidemiological, animal, and cellular studies linking exposure to BPs and phthalates to altered glucose regulation, with emphasis on the role of pancreatic β-cells. Epidemiological studies indicate that exposure to BPs and phthalates is associated with diabetes mellitus. Studies in animal models indicate that treatment with doses within the range of human exposure decreases insulin sensitivity and glucose tolerance, induces dyslipidemia, and modifies functional β-cell mass and serum levels of insulin, leptin, and adiponectin. These studies reveal that disruption of β-cell physiology by EDCs plays a key role in impairing glucose homeostasis by altering the mechanisms used by β-cells to adapt to metabolic stress such as chronic nutrient excess. Studies at the cellular level demonstrate that BPs and phthalates modify the same biochemical pathways involved in adaptation to chronic excess fuel. These include changes in insulin biosynthesis and secretion, electrical activity, expression of key genes, and mitochondrial function. The data summarized here indicate that BPs and phthalates are important risk factors for diabetes mellitus and support a global effort to decrease plastic pollution and human exposure to EDCs.

β Cell and Autophagy: What Do We Know?

Pancreatic β cells are central to glycemic regulation through insulin production. Studies show autophagy as an essential process in β cell function and fate. Autophagy is a catabolic cellular process that regulates cell homeostasis by recycling surplus or damaged cell components. Impaired autophagy results in β cell loss of function and apoptosis and, as a result, diabetes initiation and progress. It has been shown that in response to endoplasmic reticulum stress, inflammation, and high metabolic demands, autophagy affects β cell function, insulin synthesis, and secretion. This review highlights recent evidence regarding how autophagy can affect β cells' fate in the pathogenesis of diabetes. Furthermore, we discuss the role of important intrinsic and extrinsic autophagy modulators, which can lead to β cell failure.

Role of adiponectin in osteoarthritis

Osteoarthritis (OA) is a widespread and most common joint disease which leads to social cost increasing accompany with aging population. Surgery is often the final treatment option. The major progression of OA includes cartilage degradation caused by chondrocytes metabolism imbalance. So, the molecular mechanisms of action in chondrocytes may provide insights into treatment methods for OA. Adiponectin is an adipokine with many biological functions in the cell metabolism. Numerous studies have illustrated that adiponectin has diverse biological effects, such as inhibition of cell apoptosis. It regulates various functions in different organs, including muscle, adipose tissue, brain, and bone, and regulates skeletal homeostasis. However, the relationship between adiponectin and cell death in the progression of OA needs further investigation. We elaborate the structure and function and the effect of adiponectin and state the correlation and intersection between adiponectin, autophagy, inflammation, and OA. From the perspective of oxidative stress, apoptosis, pyroptosis, and autophagy, we discuss the possible association between adiponectin, chondrocyte metabolism, and inflammatory factor efforts in OA. What’s more, we summarize the possible treatment methods, including the use of adiponectin as a drug target, and highlight the potential future mechanistic research. In this review, we summarize the molecular pathways and mechanisms of action of adiponectin in chondrocyte inflammation and death and the pathogenesis of OA. We also review the research on adiponectin as a target for treating OA. These studies provide a novel perspective to explore more effective treatment options considering the complex interrelationship between inflammation and metabolism in OA.