MiR-34c-5p plays a protective role in chronic obstructive pulmonary disease via targeting CCL22.

Objective: To study the role of miR-34c-5p targeting CCL22 in affecting the progression of chronic obstructive pulmonary disease (COPD). Methods: The dual-luciferase reporter gene assay was applied to verify the targeting relationship of miR-34c-5p and CCL22. The rats were randomly assigned into Control, COPD, COPD + empty plasmids, COPD + agomir, COPD + CCL22 shRNA and COPD + agomir + CCL22 groups. COPD model was built by using cigarette smoke exposure and LPS instillation. After 28 days, the pulmonary function was examined. ELISA method was used to detect TNF-α and IL-8 levels in bronchoalveolar lavage fluid (BALF), HE staining and Masson staining to observe the pathomorphological changes of lung tissues, qRT-PCR and/or Western blot to determine miR-34c-5p and CCL22 levels, and immunohistochemical staining to measure the expression of MMP-9 and TIMP-1. Results: MiR-34c-5p could target CCL22 to down-regulate its expression. Both miR-34c-5p agomir and CCL22 shRNA could reduce breathing frequency (f), airway resistance (RI), and the levels of IL-8 and TNF-α in BALF of COPD rats with increased Cydn (dynamic lung compliance) and PIF (peak inspiratory flow). Besides, the inflammatory cell infiltration, rupture of partial alveolus, enlarged alveolar cavity, and increased deposition of collagen fibers were observed in COPD rat tissues, with rise in mean linear intercept (MLI) and reduction in mean alveolar number (MAN), which could be reversed by miR-34c-5p agomir or CCL22 shRNA. Conclusion: MiR-34c-5p may promote inflammation response and maintain the protease-antiprotease balance via targeting CCL22, which provides scientific basis for the clinical treatment of COPD.

Expression of macrophage-derived chemokine (CCL22) in atherosclerosis and regulation by histamine via the H2 receptor.

Macrophage-derived chemokine (CCL22) is a member of the CC-family of chemokines and is synthesized by monocyte-derived macrophages and dendritic cells (DCs). In this study, we investigate the relationship between monocytes/macrophages and histamine in atherosclerosis and discover that histamine levels regulate various immunologically important molecules and influences atherosclerotic progression. Immunohistochemical analysis of human atherosclerotic lesions revealed that macrophages and DCs express CCL22. The human acute monocytic leukemia cell line (THP-1) adhered to culture plates and morphologically changed to macrophage-like cells when treated with tetradecanoylphorbol-13-acetate (TPA). Macrophage-like cells derived from THP-1 cells and cultivated peripheral blood mononuclear cells (PBMCs) show similar expression of CCL22. Gene expression of CCL22 was also detected in THP-1 cells treated with histamine and the expression of the protein produced by the CCL22 gene is similar in PBMCs and THP-1 cells. In addition, the histamine H2 receptor mediated these reactions. Our results suggest that CCL22 expression in monocytes is regulated by histamine, and that CCL22 is involved centrally in the development of human atherosclerotic lesions. In conclusion, CCL22 is a marker that is a characteristic of the monocytes/ macrophages migrating into atherosclerotic lesions and histamine plays a role in regulating its expression.

Preferential migration of regulatory T cells mediated by glioma-secreted chemokines can be blocked with chemotherapy.

Despite the immunogenicity of glioblastoma multiforme (GBM), immune-mediated eradication of these tumors remains deficient. Regulatory T cells (Tregs) in the blood and within the tumor microenvironment of GBM patients are known to contribute to their dismal immune responses. Here, we determined which chemokine secreted by gliomas can preferentially induce Treg recruitment and migration. In the malignant human glioma cell lines D-54, U-87, U-251, and LN-229, the chemokines CCL22 and CCL2 were detected by intracellular cytokine analysis. Furthermore, tumor cells from eight patients with GBM had a similar chemokine expression profile. However, only CCL2 was detected by enzyme-linked immunosorbent assay, indicating that CCL2 may be the principal chemokine for Treg migration in GBM patients. Interestingly, the Tregs from GBM patients had significantly higher expression levels of the CCL2 receptor CCR4 than did Tregs from healthy controls. Glioma supernatants and the recombinant human chemokines CCL2 and CCL22 induced Treg migration and were blocked by antibodies to the chemokine receptors. Production of CCL2 by glioma cells could also be mitigated by the chemotherapeutic agents temozolomide and carmustine [3-bis (2-chloroethyl)-1-nitrosourea]. Our results indicate that gliomas augment immunosuppression by selective chemokine-mediated recruitment of Tregs into the tumor microenvironment and that modulating this interaction with chemotherapy could facilitate the development of novel immunotherapeutics to malignant gliomas.