No abstract

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) the etiology of which has not yet been fully clarified. Cytokine interleukin-10 (IL-10) plays a central role in downregulating inflammatory cascade in UC and is likely a candidate for therapeutic intervention. However, its intravenous administration is costly and inconvenient. Therefore, we established a novel IL-10 delivery system by transforming a hIL-10-containing plasmid into B. longum (BL-hIL-10) and investigated its effects on 5% dextran sulfate sodium (DSS)-induced ulcerative colitis in mice and the possible underlying mechanism. Our results show that (1) hIL-10 was expressed and secreted into the culture supernatant of BL-hIL-10 after L-arabinose induction in vitro as examined by Western blot, enzyme-linked immunosorbent assay (ELISA) and RT-PCR; (2) addition of BL-hIL-10 culture supernatant had no cytotoxic effect and morphological alteration, but significantly inhibited the enhancement of proinflammatory cytokines by lipopolysaccharide (LPS) in THP-1 cells; (3) oral administration of BL-hIL-10 alleviated colitis syndrome of the model mice, attenuated colitis-activated NF-κB pathway measured by DNA-binding assay and colitis-elevated expression of proinflammatory cytokines examined with CCK cytotoxic kits, and upregulated CD4+CD25+Foxp3+ Treg in blood and mesenteric lymph nodes measured by flow cytometry. In conclusion, BL-hIL-10 as a novel oral hIL-10 delivery system has been successfully established and oral administration of BL-hIL-10 alleviated inflammatory damage of colonic tissue in the model mice by blocking the colitis-activated NF-κB pathway and upregulating CD4+CD25+Foxp3+ Treg in blood and mesenteric lymph nodes in mice.

Nuclear factor- κB (NF- κB) plays a pivotal role in the regulation of immune and inflammatory responses. The real-time expression level of NF- κB reflects the development of ulcerative colitis (UC). Polydatin has vast pharmacological activities, including inhibiting the production of inflammatory mediators, inducing the production of antioxidants, regulating immune function, etc. The purpose of this study was to investigate the potential inhibitory effects of polydatin on NF- κB pathway activation in a mouse UC model. The results showed that polydatin treatment downregulated NF- κB p65 activity and expression, blocked the expression of TNF- α, IL-6 and IL-1 β at both mRNA and protein levels, decreased myeloperoxidase (MPO) activity, and alleviated inflammatory damage of colitis in mice with UC (p < 0.05), suggesting that the anti-inflammation effects of polydatin can be attributed, at least partially, to the blocking of the NF- κB pathway.

Tumstatin (Tum) is a powerful angiostatin that inhibits proliferation and induces apoptosis of tumorous vascular endothelial cells. A nonpathogenic and anaerobic bacterium, Bifidobacterium longum (BL), selectively localizes to and proliferates in the hypoxia location within solid tumor. The aims of this study were to develop a novel delivery system for Tum using engineered Bifidobacterium and to investigate the inhibitory effect of Tum on tumor in mice. A vector that enabled the expression of Tum under the control of the pBBADs promoter of BL was constructed and transformed into BL NCC2705 by electroporation. The mouse colon carcinoma cells CT26 (1 × 10(7)/mL) were subcutaneously inserted in the left armpit of BALB/c mice. The tumor-bearing mice were treated with Tum-transformed BL, and green fluorescent protein (GFP)-transformed BL was used as a negative control. The microvessel density (MVD) in the transplanted tumor was determined, and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling was used to detect apoptosis of vascular endothelial cells in transplanted tumor. The in vitro expression of Tum was examined in BL after l-arabinose induction. Bifidobacterium longum with pBBAD-Tum (BL-Tum) showed significant antitumor effect in tumor-bearing mice. The weight, volume, growth, and MVD, as well as the percentage of apoptotic vascular endothelial cells of transplanted tumors in the tumor-bearing mice treated with Tum-transformed BL were all significantly lower than those in the GFP negative control group. Intragastric administration, injection in tumor and vena caudalis injection of Tum-transformed BL exerted marked antitumor effects in tumor-bearing mice. This is the first demonstration of the utilization of Tum-transformed BL as a specific gene delivery system for treating tumor.

Colon adenocarcinoma (COAD) is a fatal malignancy with high morbidity and mortality rates globally. Pinin (PNN), a desmosome associated protein, has been revealed as a tumour driver in several malignancies. This study aims to probe the expression and role of PNN in COAD and the underlying mechanism. PNN was expressed at high levels in clinically collected COAD tumours and was linked to poor prognosis of patients. Downregulation of PNN reduced glucose uptake, lactate production and ATP levels in COAD cells and suppressed cell proliferation, migration and invasiveness.Methyltransferase like 3 (METTL3) was positively associated with PNN levels in COAD tumour tissues. RNA immunoprecipitation and N 6 -methyladenosine (m 6 A) quantification assays indicated that METTL3 enhanced PNN mRNA stability and expression in COAD through m 6 A modification with the involvement of the m 6 A 'reader' protein YT521-B homology domain family member 1. Downregulation of METTL3 reduced COAD cell glycolysis and proliferation in vitro and suppressed growth and metastasis of xenograft tumours in vivo, but further overexpression of PNN restored malignant behaviours of COAD cells and tumour growth. In summary, this study demonstrates that METTL3 promotes PNN mRNA stability and expression in COAD through m 6 A modification, which augments glycolysis and proliferation of COAD cells and leads to the resultant tumour progression.