TRPV4缺失通过重塑肠道菌群及促进炎症因子分泌加剧小鼠结直肠癌进展OA

Objective Host genes regulate the composition and function of gut microbiota,thereby influencing the development of colorectal cancer(CRC).This study aims to investigate the mechanisms by which host gene TRPV4 deficiency exacerbates CRC in mice through remodeling gut microbiota and promoting inflammatory cytokine secretion.Methods TRPV4 knockout(TRPV4-/-)mice were used to establish a CRC mouse model induced by dextran sodium sulfate(DSS)and azoxymethane(AOM).Male TRPV4-/-and wild-type mice(6 to 8 weeks old)were stratified by body weight and randomly divided into TRPV4-/-group(n=7)and WT group(n=7).The mouse model of CRC was established through a single intraperitoneal injection of 10 mg/kg AOM on day 1 of week 1;from day 7,drinking water containing 1.5%DSS for 7 consecutive days,followed by 2 weeks of regular water,with this DSS treatment cycle being repeated for 3 times;a second intraperitoneal injection of 10 mg/kg AOM on day 1 of week 6.CRC progression was assessed with tumor number,size,burden,colon length,spleen weight,colonic morphology(HE staining)and pathological score,and immunohistochemical detection of proliferating cell nuclear antigen(PCNA).Additionally,male TRPV4-/-and wild-type mice(6 to 8 weeks old)were stratified by body weight and randomly divided into antibiotic cocktail(ABX)-TRPV4-/-group(n=5)and ABX-WT group(n=5).The ABX mixture was used to deplete the gut microbiota to evaluate the microbiota-dependent effects of TRPV4 on CRC.Fecal samples were collected from the TRPV4-/-group(n=19)and WT group(n=21)before modeling,and then subjected to 16S rRNA sequencing to determine the effect of TRPV4 gene on mouse gut microbiota.RNA sequencing was performed on mouse colonic tissue;Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis was used to examine enrichment of differentially expressed genes,and fecal bacteria-cell co-incubation experiments were conducted in vitro.Results The TRPV4-/-group exhibited significantly increased tumor incidence(P=0.037 9),tumor burden(P=0.000 3),histopathological score(P<0.000 1),and PCNA-positive rate(P<0.000 1),and shorter colon length(P=0.001 2)compared with the WT group.After ABX treatment,no significant differences were observed between the TRPV4-/-group and WT group in tumor incidence,tumor burden,colon length,histopathological score,or PCNA positive rate(P>0.05).16S rRNA sequencing demonstrated that TRPV4 deficiency reshaped the gut microbiota structure,with significant differences in β diversity between the TRPV4-/-and WT groups(P=0.001)and distinct microbiota composition profiles.Colon tissue RNA-seq results revealed 218 significantly upregulated and 152 downregulated genes in TRPV4-/-mice.KEGG pathway enrichment showed that differentially expressed genes were significantly enriched in cytokine signaling pathways and TNF signaling pathways.In vitro co-incubation results demonstrated that the transcription levels of TNF-α(P<0.000 1),IL-1β(P<0.000 1),and IL-23(P<0.000 1)were significantly upregulated in TRPV4-/-microbiota-cell co-cultures.Conclusion The gut microecology formed by TRPV4 deficiency may exacerbate CRC by promoting the secretion of inflammation-related cytokines.