Mindin serves as a tumour suppressor gene during colon cancer progression through MAPK/ERK signalling pathway in mice.

Mindin is important in broad spectrum of immune responses. On the other hand, we previously reported that mindin attenuated human colon cancer development by blocking angiogenesis through Egr-1-mediated regulation. However, the mice original mindin directly suppressed the syngenic colorectal cancer (CRC) growth in our recent study and we aimed to further define the role of mindin during CRC development in mice. We established the mouse syngeneic CRC CMT93 and CT26 WT cell lines with stable mindin knock-down or overexpression. These cells were also subcutaneously injected into C57BL/6 and BALB/c mice as well as established a colitis-associated colorectal cancer (CAC) mouse model treated with lentiviral-based overexpression and knocked-down of mindin. Furthermore, we generated mindin knockout mice using a CRISPR-Cas9 system with CAC model. Our data showed that overexpression of mindin suppressed cell proliferation in both of CMT93 and CT26 WT colon cancer cell lines, while the silencing of mindin promoted in vitro cell proliferation via the ERK and c-Fos pathways and cell cycle control. Moreover, the overexpression of mindin significantly suppressed in vivo tumour growth in both the subcutaneous transplantation and the AOM/DSS-induced CAC models. Consistently, the silencing of mindin reversed these in vivo observations. Expectedly, the tumour growth was promoted in the CAC model on mindin-deficient mice. Thus, mindin plays a direct tumour suppressive function during colon cancer progression and suggesting that mindin might be exploited as a therapeutic target for CRC.

The pattern-recognition molecule mindin binds integrin Mac-1 to promote macrophage phagocytosis via Syk activation and NF-κB p65 translocation.

Mindin has a broad spectrum of roles in the innate immune system, including in macrophage migration, antigen phagocytosis and cytokine production. Mindin functions as a pattern-recognition molecule for microbial pathogens. However, the underlying mechanisms of mindin-mediated phagocytosis and its exact membrane receptors are not well established. Herein, we generated mindin-deficient mice using the CRISPR-Cas9 system and show that peritoneal macrophages from mindin-deficient mice were severely defective in their ability to phagocytize E  coli. Phagocytosis was enhanced when E  coli or fluorescent particles were pre-incubated with mindin, indicating that mindin binds directly to bacteria or non-pathogen particles and promotes phagocytosis. We defined that 131 I-labelled mindin binds with integrin Mac-1 (CD11b/CD18), the F-spondin (FS)-fragment of mindin binds with the αM -I domain of Mac-1 and that mindin serves as a novel ligand of Mac-1. Blockade of the αM -I domain of Mac-1 using either a neutralizing antibody or si-Mac-1 efficiently blocked mindin-induced phagocytosis. Furthermore, mindin activated the Syk and MAPK signalling pathways and promoted NF-κB entry into the nucleus. Our data indicate that mindin binds with the integrin Mac-1 to promote macrophage phagocytosis through Syk activation and NF-κB p65 translocation, suggesting that the mindin/Mac-1 axis plays a critical role during innate immune responses.

Glycerol monolaurate ameliorates DSS-induced acute colitis by inhibiting infiltration of Th17, neutrophils, macrophages and altering the gut microbiota.

Background and aims: Inflammatory bowel disease (IBD) places a heavy medical burden on countries and families due to repeated and prolonged attacks, and the incidence and prevalence of IBD are increasing worldwide. Therefore, finding an effective treatment is a matter of great urgency. Glycerol monolaurate (GML), which has a twelve-carbon chain, is a compound naturally found in human breast milk. Some studies have shown that GML has antibacterial and anti-inflammatory effects. However, the specific mechanism of action remains unclear. Methods: Acute colitis was established in mice using 3% DSS, and glycerol monolaurate (500 mg·kg-1) was administered for two weeks. QPCR and western blotting were performed to examine the inflammatory status. Mice described were subjected to flow cytometry analysis for immune cell activation. Results: GML treated alleviated macroscopic symptoms such as shortened colons, increased spleen weight, and caused weight loss in mice with DSS-induced colitis. In addition, GML decreased the expression of pro-inflammatory factors (NF-α, IL-1ß and IL-1α) and increased the expression of anti-inflammatory factors (IL-10 and TGF-ß). GML inhibited the activation of the MAPK and NF-κB signalling pathways, improved tissue damage, and increased the expression of intestinal tight junction proteins. In addition, LPMCs extracted from intestinal tissue via flow cytometry showed that GML treatment led to a decrease of Th17 cells, Neutrophils and Macrophages. 16S rDNA sequencing showed that GML increased the abundance of commensal bacterium such as Akkermansia and Lactobacillus murinus. Conclusions: We showed that oral administration of GML ameliorated DSS-induced colitis by inhibiting infiltration of Th17 cells, Neutrophils, and Macrophages, protecting the intestinal mucosal barrier and altered the abundance of commensal bacterium. This study provides new insights into the biological function and therapeutic potential of GML in the treatment of IBD.