IL-34 attenuates acute T cell-mediated rejection following renal transplantation by upregulating M2 macrophages polarization

Bin Ni; Dongliang Zhang; Hai Zhou; Ming Zheng; Zijie Wang; Jun Tao; Zhijian Han; Xiaobin Ju; Ruoyun Tan; Min Gu

doi:10.1016/j.heliyon.2024.e24028

IL-34 attenuates acute T cell-mediated rejection following renal transplantation by upregulating M2 macrophages polarization

Heliyon. 2024 Jan 3;10(1):e24028. doi: 10.1016/j.heliyon.2024.e24028. eCollection 2024 Jan 15.

Authors

Bin Ni¹, Dongliang Zhang¹, Hai Zhou¹, Ming Zheng¹, Zijie Wang², Jun Tao², Zhijian Han², Xiaobin Ju², Ruoyun Tan², Min Gu^{1

2}

Affiliations

¹ Department of Urology, the Second Affiliated Hospital of Nanjing Medical University, 121# Jiangjiayuan Road, Nanjing, Jiangsu, China.
² Department of Urology, the First Affiliated Hospital of Nanjing Medical University, 300# Guangzhou Road, Nanjing, Jiangsu, China.

Abstract

Objective: To investigate the role of Interleukin-34 (IL-34) in acute T cell-mediated rejection (TCMR) following renal transplantation.

Methods: The mice acute TCMR model of renal transplantation was established and identified by hematoxylin and eosin (HE) and immunohistochemistry (IHC) staining. Then, IHC staining of IL-34 was also performed to determine the expression of IL-34 in allografts. Recipients were infected with IL-34 overexpression adeno-associated virus, infection efficiency of which was estimated by enzyme linked immunosorbent assay (ELISA), Western blot, and immunofluorescence. HE and IHC staining were used to estimate the grades of TCMR. Flow cytometry was performed on lymphocytes in spleens of recipients including regulatory T cells (Tregs) and M2 macrophages. The expression of cytokines in vivo was analyzed by Mouse Cytokine Grp I Panel. Finally, Tregs and M2 macrophages were cultured in vitro and treated with IL-34 to observe the effects of IL-34 on the differentiation of the cells.

Results: The mouse TCMR model was successfully established by HE, periodic acid shiff (PAS), CD4 and CD8 IHC staining. The expression of IL-34 was significantly decreased in allografts with TCMR. BALB/c mice were successfully infected with IL-34 overexpression adeno-associated virus. Subsequently, the grade of rejection in mice TCMR model was evaluated by HE and IHC staining according to Banff criteria. It is suggested that the grade of TCMR in IL-34 overexpressed mice was significantly decreased. IHC staining and Flow cytometry showed that the proportion of Tregs and M2 macrophages in the spleens and allografts were significantly increased in IL-34 overexpressed mice. Serum levels of interferon-gamma (IFN-γ), IL-17 and tumor necrosis factor-alpha (TNF-α) were downregulated in IL-34 overexpressed mice. Moreover, IL-34 could promote macrophage M2 polarization, while failed to promote differentiation of naïve T cells into Tregs in vitro.

Conclusion: Overexpression of IL-34 may attenuate the progression of TCMR episodes in allografts by increasing the polarization of M2 macrophages in the spleens and allografts, which may become a potential therapeutic strategy for TCMR.

Keywords: IL-34; Kidney transplantation; M2 macrophage; T cell-mediated rejection.