Gr1+ myeloid-derived suppressor cells participate in the regulation of lung-gut axis during mouse emphysema model

Chronic obstructive pulmonary disease (COPD) is often accompanied by intestinal symptoms. Myeloid-derived suppressor cells (MDSCs) possess immunosuppressive ability in cancer, chronic inflammation, and infection. The

These data provide evidence for lung-gut axis in emphysema model and the participants of MDSCs.

Adult male C57BL/6 mice were exposed to cigarette smoke (CS) for 6 months or injected with porcine pancreas elastase to establish emphysema models. Flow cytometry and immunohistochemistry analysis revealed the distribution of MDSCs in tissues. The expression of inflammation and MDSCs-associated genes in the small intestine and colon were analyzed by real-time PCR.

The small intestine and colon of CS-induced emphysematous mice displayed pathological changes, CD4+/CD8+ T cells imbalance, and increased neutrophils, monocytes, and macrophages infiltration. A significant expansion of MDSCs could be seen in CS-affected respiratory and gastrointestinal tract. Importantly, higher expression of MDSCs-related effector molecules inducible nitric oxide synthase (INOS), NADPH oxidase 2 (NOX2), and arginase 1 (ARG-1) suggested the immunosuppressive effect of migrated MDSCs (P<0.05).