Immunopathogenesis of Progressive Scarring Trachoma: Results of a 4-Year Longitudinal Study in Tanzanian Children
INFECTION AND IMMUNITY
Authors: Derrick, Tamsyn; Ramadhani, Athumani M.; Macleod, David; Massae, Patrick; Mafuru, Elias; Aiweda, Malisa; Mbuya, Kelvin; Makupa, William; Mtuy, Tara; Bailey, Robin L.; Mabey, David C. W.; Holland, Martin J.; Burton, Matthew J.
Abstract
Trachoma is initiated during childhood following repeated conjunctival infection with Chlamydia trachomatis, which causes a chronic inflammatory response in some individuals that leads to scarring and in-turning of the eyelids in later life. There is currently no treatment to halt the progression of scarring trachoma due to an incomplete understanding of disease pathogenesis. A cohort study was performed in northern Tanzania in 616 children aged 6 to 10 years at enrollment. Every 3 months for 4 years, children were examined for clinical signs of trachoma, and conjunctival swabs were collected for C. trachomatis detection and to analyze the expression of 46 immunofibrogenic genes. Data were analyzed in relation to progressive scarring status between baseline and the final time point. Genes that were significantly associated with scarring progression included those encoding proinflammatory chemokines (CXCLS, CCL20, CXCL13, and CCL18), cytokines (1L23A, 119, and IL1B), matrix modifiers (MMP12 and SPARCL1), immune regulators (IDOo1, SOCS3, and IL10), and a proinflammatory antimicrobial peptide (S100A7). In response to C trachomatis infection, IL23A and PDGF were significantly upregulated in scarring progressors relative to in nonprogressors. Our findings highlight the importance of innate proinflammatory signals from the epithelium and implicate interleukin 23A (IL-23A)-responsive cells in driving trachomatous scarring, with potential key mechanistic roles for PDGFB, MMP12, and SPARCL1 in orchestrating fibrosis.
Gavage of Fecal Samples From Patients With Colorectal Cancer Promotes Intestinal Carcinogenesis in Germ-Free and Conventional Mice
GASTROENTEROLOGY
Authors: Wong, Sunny H.; Zhao, Liuyang; Zhang, Xiang; Nakatsu, Geicho; Han, Juqiang; Xu, Weiqi; Xiao, Xue; Kwong, Thomas N. Y.; Tsoi, Ho; Wu, William K. K.; Zeng, Benhua; Chan, Francis K. L.; Sung, Joseph J. Y.; Wei, Hong; Yu, Jun
Abstract
BACKGROUND & AIMS: Altered gut microbiota is implicated in development of colorectal cancer (CRC). Some intestinal bacteria have been reported to potentiate intestinal carcinogenesis by producing genotoxins, altering the immune response and intestinal microenvironment, and activating oncogenic signaling pathways. We investigated whether stool from patients with CRC could directly induce colorectal carcinogenesis in mice. METHODS: We obtained stored stool samples from participants in a metagenome study performed in Hong Kong. Conventional (male C57BL/6) mice were given azoxy-methane to induce colon neoplasia after receiving a course of antibiotics in drinking water. Mice were gavaged twice weekly with stool from 5 patients with CRC or 5 healthy individuals (controls) for 5 weeks. Germ-free C57BL/6 mice were gavaged once with stool from 5 patients with CRC or 5 controls. We collected intestinal tissues from mice and performed histology, immunohistochemistry, expression microarray, quantitative polymerase chain reaction, immunoblot, and flow cytometry analyses. We performed 16S ribosomal RNA gene sequencing analysis of feces from mice. RESULTS: Significantly higher proportions of conventional mice fed with stool from individuals with CRC than control stool developed high-grade dysplasia (P < .05) and macroscopic polyps (P < .01). We observed a higher proportion of proliferating (Ki-67-positive) cells in colons of germ-free mice fed with stool from patients with CRC vs those fed with stool from controls (P < .05). Feces from germ-free and conventional mice fed with stool from patients with CRC vs controls contained different microbial compositions, with lower richness in mice fed with stool from patients with CRC. Intestines collected from conventional and germ-free mice fed with stool from patients with CRC had increased expression of cytokines that modulate inflammation, including C-X-C motif chemokine receptor 1, C-X-C motif chemokine receptor 2, interleukin 17A (IL17A), IL22, and IL23A. Intestines from conventional and germ-free mice fed with stool from patients with CRC contained higher proportions of T-helper 1 (Th1) cells (2.25% vs 0.44%) and Th17 cells (2.08% vs 0.31%) (P < .05 for each) than mice fed with stool from controls. Real-time polymerase chain reaction arrays revealed up-regulation of genes involved in cell proliferation, stemness, apoptosis, angiogenesis, invasiveness, and metastasis in mice fed with stool from patients with CRC. CONCLUSIONS: We fed stool samples from patients with CRC and heathy individuals to germ-free mice and conventional mice with azoxymethane. We found stool from patients with CRC to increase the numbers of polyps, levels of intestinal dysplasia and proliferation, markers of inflammation, and proportions of Th1 and Th17 cells in colon, compared with stool from individuals without CRC. This study provides evidence that the fecal microbiota from patients with CRC can promote tumorigenesis in germ-free mice and mice given a carcinogen.