Gegen Qinlian Decoction Alleviates Experimental Colitis and Concurrent Lung Inflammation by Inhibiting the Recruitment of Inflammatory Myeloid Cells and Restoring Microbial Balance

Abstract

Yalan Li,1,* Na Li,1,* Jiajing Liu,1 Tieshan Wang,2 Ruijuan Dong,3 Dongyu Ge,3 Guiying Peng1 1Department of Immunology and Microbiology, School of Life Sciences, Beijing University of Chinese Medicine, Beijing, People’s Republic of China; 2Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, People’s Republic of China; 3Experimental Teaching Center, School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Guiying Peng, Email [email protected]: Ulcerative colitis (UC) as one of the intractable diseases in gastroenterology seriously threatens human health. Respiratory pathology is a representative extraintestinal manifestation of UC affecting the quality of life of patients. Gegen Qinlian Decoction (GQD) is a classical traditional Chinese medicine prescription for UC or acute lung injury. This study was aimed to reveal the therapeutic effect of GQD on UC and its pulmonary complications and uncover its molecular mechanism mediated by myeloid cells and microbiota.Methods: Mice with DSS-induced colitis were orally administrated with GQD. Overall vital signs were assessed by body weight loss and disease activity index (DAI). Pulmonary general signs were evaluated by pulmonary pathology and lung function. The mechanism of GQD relieving UC was characterized by detecting myeloid cells (neutrophils, macrophages, inflammatory monocytes, and resident monocytes) in colonic and lung tissues, related inflammatory cytokines, as well as the microbiota in bronchoalveolar lavage fluid (BALF) and feces.Results: GQD significantly reduced weight loss, DAI scores, and lung injury but improved the lung function of colitis mice. The DSS-induced colonic and concurrent pulmonary inflammation were also alleviated by GQD, as indicated by the down-regulated expressions of inflammatory cytokines (TNF-α, IL-1β, IL-6, CCR2, and CCL2) and the suppressed recruitment of neutrophils and inflammatory monocytes. Meanwhile, GQD greatly improved intestinal microbiota imbalance by enriching Ruminococcaceae UCG-013 while decreasing Parabacteroides, [Eubacterium]_fissicatena_group, and Akkermansia in the feces of colitis mice. Expectantly, GQD also restored lung microbiota imbalance by clearing excessive Coprococcus 2 and Ochrobactrum in the BALF of colitis mice. Finally, significant correlations appeared between GQD-mediated specific bacteria and inflammatory cytokines or immune cells.Conclusion: GQD could alleviate UC by decreasing excessive inflammatory myeloid cells and cytokines, and reshaping the microbiota between the colon and lung, which contributes to clarifying the mechanism by which GQD ameliorates colitis-associated pulmonary inflammation.Keywords: Gegen Qinlian Decoction, ulcerative colitis, lung and intestinal microbiota, pulmonary inflammation, myeloid cells

Keywords

• gegen qinlian decoction
• ulcerative colitis
• lung and intestinal microbiota
• pulmonary inflammation
• myeloid cells