PM2.5 induces autophagy-dependent ferroptosis by endoplasmic reticulum stress in SH-SY5Y cells.

Fine particulate matter (PM2.5 ) has been a global environmental problem threatening public health in recent years. PM2.5 exposure was associated with an increased risk of neurodegenerative diseases related to neuronal apoptosis. Ferroptosis is a nonapoptotic form of programmed the cell death, characterized by excess iron-dependent lipid peroxidation products. Whether PM2.5 could induce ferroptosis in cells and thus be involved in its neurotoxicity is unknown. In this study, we found that PM2.5 induced endoplasmic reticulum stress, apoptosis, autophagy, and ferroptosis in neuroblastoma human neuroblastoma cells (SH-SY5Y). Interestingly, ferroptosis was the predominant form of mortality in the presence of high doses of PM2.5 exposure. In addition, the endoplasmic reticulum stress inhibitor 4-phenylbutyric acid (4-PBA) inhibited PM2.5 -induced cellular autophagy, apoptosis, and ferroptosis. Autophagy inhibitors chloroquine (CQ) alleviated PM2.5 -induced ferroptosis but did not reverse apoptosis. We also found that inhibition of both endoplasmic reticulum stress and autophagy reversed the PM2.5 -induced increase in the expression level of cytophagy nuclear receptor coactivator 4 (NCOA4). Our results suggested that PM2.5 -induced ferroptosis in SH-SY5Y cells was autophagy-dependent ferroptosis due to endoplasmic reticulum stress, which might be associated with the elevation of iron content caused by NCOA4-mediated ferritin autophagy.

Brain-gut-liver axis: Chronic psychological stress promotes liver injury and fibrosis via gut in rats.

Background: The effect of chronic psychological stress on hepatitis and liver fibrosis is concerned. However, its mechanism remains unclear. We investigated the effect and mechanism of chronic psychological stress in promoting liver injury and fibrosis through gut. Methods: Sixty male SD rats were randomly assigned to 6 groups. Rat models of chronic psychological stress (4 weeks) and liver fibrosis (8 weeks) were established. The diversity of gut microbiota in intestinal feces, permeability of intestinal mucosa, pathologies of intestinal and liver tissues, collagen fibers, protein expressions of toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), nuclear factor kappa ß (NF-κß), tumor necrosis factor α (TNF-α) and interleukin 1 (IL-1) in liver tissue, liver function and coagulation function in blood and lipopolysaccharide (LPS) in portal vein blood were detected and analyzed. Results: The diversities and abundances of gut microbiota were significant differences in rats among each group. The pathological lesions of intestinal and liver tissues, decreased expression of occludin protein in intestinal mucosa, deposition of collagen fibers and increased protein expression of TLR4, MyD88, NF-κß, TNF-α and IL-1 in liver tissue, increased LPS level in portal vein blood, and abnormalities of liver function and coagulation function, were observed in rats exposed to chronic psychological stress or liver fibrosis. There were significant differences with normal rats. When the dual intervention factors of chronic psychological stress and liver fibrosis were superimposed, the above indicators were further aggravated. Conclusion: Chronic psychological stress promotes liver injury and fibrosis, depending on changes in the diversity of gut microbiota and increased intestinal permeability caused by psychological stress, LPS that enters liver and acts on TLR4, and active LPS-TLR4 pathway depend on MyD88. It demonstrates the possibility of existence of brain-gut-liver axis.

Benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide induces ferroptosis in neuroblastoma cells through redox imbalance.

As a widespread environmental pollutant, benzo(a)pyrene-7,8-diol-9,10-epoxide (BPDE)-induced neurotoxicity has received increasing attention. Studies have shown that BPDE-induced neurodegeneration is due partly to neuronal apoptosis. Unlike apoptosis, ferroptosis is a non-apoptotic form of programmed cell death, but its specific role in the neurotoxicity of BPDE remains unclear. In this work, we investigated the ferroptosis in BPDE-induced cell death in human neuroblastoma cell line SH-SY5Y using a specific pharmacological inhibitor. Lipid peroxides, malondialdehyde production, glutathione / glutathione peroxidase activity, superoxide dismutase activity, and iron content were evaluated. Consistent with previous studies, our data showed that 0.5 µM BPDE poisoning for 24 hr could induce cell apoptosis and that cell survival could be improved by using apoptosis inhibitors. But with prolonged exposure time (72 hr) or increased exposure dose (1.0 µM), we have elucidated and validated that BPDE triggered ferroptosis in human SH-SY5Y cells. We also revealed that suppression of ferroptosis by specific inhibitors, ferrostatin-1 and deferoxamine, significantly rescued the phenotypes of ferroptosis induced by BPDE. BPDE downregulated Nrf2 and its target genes related to redox regulation, GPX4 and SLC7A11, but upregulated HO-1. Our results first demonstrated that BPDE caused cytotoxic effects on cell death via apoptosis and ferroptosis. Most notably, long-term environmental exposure to BPDE becomes a concern due to ferroptosis. Redox imbalance is controlled by the Nrf2, SLC7A11, and HO-1, through which lipid peroxides and ferrous ion accumulation cause ferroptosis after BPDE treatment. These findings highlight that targeting ferroptosis could serve as an effective protective strategy for neurotoxicity of BPDE.

Short-term effect and adverse events of adalimumab versus placebo in inducing remission for moderate-to-severe ulcerative colitis: a meta-analysis.

BACKGROUND: Adalimumab is used in an attempt to maintain remission for Ulcerative colitis. This study was to evaluate the efficacy and adverse events of adalimumab compared with placebo in inducing remission of Ulcerative colitis. METHODS: MEDLINE, EMBASE, the Cochrane Controlled Trials Register, OVID, BIOSIS, CNKI, and Google were searched. All randomized trials comparing adalimumab with placebo in inducing remission of moderate-to-severe ulcerative colitis were included. RESULTS: Two randomized controlled trials with a total of 754 participants met the inclusion criteria. The pooled risk ratio (RR) of clinical remission was 1.85 (95% confidence interval (CI) 1.26 to 2.72) following adalimumab treatment. RR of clinical response was 1.40 (95% CI 1.19 to 1.65) while that of mucosal healing was 1.23 (95% CI 1.03 to 1.47). RR of any adverse events was 1.00 (95% CI 0.93 to 1.09). CONCLUSION: Compared with placebo, administration of adalimumab may increase the proportion of patients with moderate-to-severe ulcerative colitis attaining clinical remission, clinical response and mucosal healing. Adalimumab is also tolerated well in these patients.

Ulcerative colitis with inflammatory polyposis in a teenage boy: a case report.

Ulcerative colitis in addition to inflammatory polyposis is common. The benign sequel of ulcerative colitis can sometimes mimic colorectal carcinoma. This report describes a rare case of inflammatory polyposis with hundreds of inflammatory polyps in ulcerative colitis which was not easy to distinguish from other polyposis syndromes. A 16-year-old Chinese male suffering from ulcerative colitis for 6 mo underwent colonoscopy, and hundreds of polyps were observed in the sigmoid, causing colonic stenosis. The polyps were restricted to the sigmoid. Although rectal inflammation was detected, no polyps were found in the rectum. A diagnosis of inflammatory polyposis and ulcerative colitis was made. The patient underwent total colectomy and ileal pouch anal anastomosis. The patient recovered well and was discharged on postoperative day 8. Endoscopic surveillance after surgery is crucial as ulcerative colitis with polyposis is a risk factor for colorectal cancer. Recognition of polyposis requires clinical, endoscopic and histopathologic correlation, and helps with chemoprophylaxis of colorectal cancer, as the drugs used postoperatively for colorectal cancer, ulcerative colitis and polyposis are different.

Serum IL-17 and IL-6 increased accompany with TGF-ß and IL-13 respectively in ulcerative colitis patients.

PURPOSES: To explorer the serum level of pro- and anti-inflammatory cytokines in the patients of ulcerative colitis and irritable bowel disease. And analyze the correlation between the cytokine's levels and disease's activity of ulcerative colitis patients. METHODS: Serum cytokines of ulcerative colitis and irritable bowel syndrome with diarrhea patients including IL-6, IL-10, IL-13, IL-17, TNF-α and TGF-ß were analyzed by enzyme linked immunosorbent assay, and ulcerative colitis activity were assessed by Mayo scoring system. The correlation of the serum level of cytokines and ulcerative colitis activity were analyzed by the SPSS 19.0 software. RESULTS: Compared with healthy people, the serum level of IL-6, IL-10, IL-13, IL-17, TNF-α and TGF-ß were elevated in ulcerative colitis patients. There is no direct correlation between each cytokines analyzed and the Mayo score. And the level of IL-6 is relevant to IL-13 (r=0.364, P=0.029), and the level of IL-17 is relevant to TGF-ß (r=0.336, P=0.045). CONCLUSION: When the pro-inflammatory cytokines increase in the serum of ulcerative colitis, the anti-inflammatory cytokines were increased concomitantly, Some cytokines are positive correlated, such as IL-6 and IL-13, IL-17 and TGF-ß, the mechanism of which is complex and needs further investigation.