PURPOSE: Interleukin-17 (IL-17) is a proinflammatory cytokine that plays important roles in inflammation, autoimmunity, and cancer. The purpose of this study was to determine if IL-17 indirectly regulates macrophage differentiation through up-regulation of cyclooxygenase-2 (COX-2) expression in the cancer cell lines. MATERIALS AND METHODS: Human cervical cancer HeLa, human lung cancer A549, and mouse prostate cancer Myc-CaP/CR cell lines were treated with recombinant IL-17; Western blot analysis, enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction analysis were utilized to examine the cellular responses. RESULTS: IL-17 up-regulated expression of COX-2 mRNA and protein in HeLa, A549, and Myc-CaP/CR cell lines. IL-17's effects were mediated through nuclear factor-kappaB and ERK1/2 signaling pathways as the inhibitors of these pathways could inhibit IL-17-induced COX-2 expression. The conditional medium obtained from the cancer cells contained prostaglandin E2, the levels of which were increased by IL-17 treatment. When treated with the conditional medium, particularly with the IL-17-induced conditional medium, mouse RAW264.7 macrophages and human THP-1 monocytes expressed higher levels of IL-10 (a marker of M2 macrophages) than inducible nitric oxide synthase or tumor necrosis factor alpha (markers of M1 macrophages). In contrast, when RAW264.7 and THP-1 cells were treated directly with IL-17, expression of these marker genes was not markedly changed. CONCLUSION: The results of this study suggest that IL-17 indirectly promotes M2 macrophage differentiation through stimulation of the COX-2/PGE2 pathway in the cancer cells, thus IL-17 plays an indirect role in regulating the tumor immune microenvironment.
Animals ; Autoimmunity ; Blotting, Western ; Cell Line ; Cyclooxygenase 2 ; Dinoprostone ; Enzyme-Linked Immunosorbent Assay ; Humans ; Inflammation ; Interleukin-10 ; Interleukin-17* ; Lung Neoplasms ; Macrophages* ; Mice ; Monocytes ; Nitric Oxide Synthase Type II ; Prostatic Neoplasms ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; Tumor Microenvironment ; Tumor Necrosis Factor-alpha ; Up-Regulation ; Uterine Cervical Neoplasms

OBJECTIVE: To investigate the protective effect of procyanidin B2 (PCB2) on the intestinal barrier and against enteritis in mice with trinitrobenzene sulphonic acid (TNBS)-induced colitis and explore the possible mechanism. METHODS: A mouse model of TNBS-induced colitis was established in male Balb/c mice aged 6-8 weeks. The successfully established mouse models were randomly divided into PCB2 treatment group (=10) and model group (=10) and were treated with daily intragastric administration of PCB2 (100 mg/kg, 0.2 mL) and 0.2 mL normal saline, respectively. After 4 weeks, the disease symptoms, intestinal inflammation, intestinal mucosal cell barrier function and the changes in PI3K/AKT signaling were evaluated using HE staining, immunofluorescence assay and Western blotting. RESULTS: The disease activity index of the mice was significantly lower and the mean body weight was significantly greater in PCB2 group than in the model group in the 3rd and 4th weeks of intervention ( < 0.05). The levels of colonic inflammation and intestinal mucosal inflammatory mediators IL-1β and TNF-α were significantly lower while IL-10 was significantly higher in PCB2 group than in the model group ( < 0.05). Compared with those in the model group, the mice in PCB2 treatment group showed a significantly lower positive rate of bacterial translocation in the mesenteric lymph nodes and a lower thiocyanate-dextran permeability of the intestinal mucosa ( < 0.05). Western blotting showed that PCB2 treatment significantly increased the expressions of claudin-1 and ZO-1 ( < 0.05) and significantly lowered the expression levels of p-PI3K and p-AKT in the intestinal mucosa as compared with those in the model group ( < 0.05). CONCLUSIONS PCB2 suppresses intestinal inflammation and protects intestinal mucosal functions and structural integrity by inhibiting intestinal PI3K/AKT signaling pathway, suggesting the potential of PCB2 as a new drug for Crohn's disease.
Animals ; Biflavonoids ; Catechin ; Colitis ; chemically induced ; Colon ; Enteritis ; Intestinal Mucosa ; Male ; Mice ; Phosphatidylinositol 3-Kinases ; Proanthocyanidins ; Trinitrobenzenesulfonic Acid

GGGGCC repeat expansions in the C9ORF72 gene are the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia (c9ALS/FTD). It has been reported that hexanucleotide repeat expansions in C9ORF72 produce five dipeptide repeat (DPR) proteins by an unconventional repeat-associated non-ATG (RAN) translation. Within the five DPR proteins, poly-PR and poly-GR that contain arginine are more toxic than the other DPRs (poly-GA, poly-GP, and poly-PA). Here, we demonstrated that poly-PR peptides transferred into cells by endocytosis in a clathrin-dependent manner, leading to endoplasmic reticulum stress and cell death. In SH-SY5Y cells and primary cortical neurons, poly-PR activated JUN amino-terminal kinase (JNK) and increased the levels of p53 and Bax. The uptake of poly-PR peptides by cells was significantly inhibited by knockdown of clathrin or by chlorpromazine, an inhibitor that blocks clathrin-mediated endocytosis. Inhibition of clathrin-dependent endocytosis by chlorpromazine significantly blocked the transfer of poly-PR peptides into cells, and attenuated poly-PR-induced JNK activation and cell death. Our data revealed that the uptake of poly-PR undergoes clathrin-dependent endocytosis and blockade of this process prevents the toxic effects of synthetic poly-PR peptides.