305
Views
3
CrossRef citations to date
0
Altmetric
Original Articles

IL-21 impairs pro-inflammatory activity of M1-like macrophages exerting anti-inflammatory effects on rheumatoid arthritis

, , , , &
Pages 75-85 | Received 03 Sep 2021, Accepted 13 Nov 2021, Published online: 29 Nov 2021
 

Abstract

Objective:Macrophages are the main source of inflammatory mediators and play important roles in the pathogenesis of rheumatoid arthritis (RA). Interleukin-21 (IL-21) regulates both innate and adaptive immune responses and exerts major effects on inflammatory responses that promote the development of RA. However, its effect on macrophage polarisation remains unclear.

Methods:CD14+ monocytes of the peripheral blood of Human healthy donors (HD) and RA, and macrophages of RA synovial fluid (RA-SF MΦs) were isolated. IL-21 receptor (IL-21R) was detected by flow cytometry. Cytokine production by MΦs from different sources pre-treated with IL-21 and/or LPS was measured by real-time polymerase chain reaction (RT-PCR) and ELISA. CD14+ monocytes were differentiated into M1-like and M2-like macrophages via stimulation with GM-CSF, interferon-γ (IFN-γ), and LPS or M-CSF, IL-4, and IL-13, respectively. To determine the effect of IL-21 on macrophage polarisation, macrophage phenotypes, gene expression, and cytokine secretion were detected by flow cytometry, RT-PCR, and ELISA. TLR4 and ERK1/2 were determined by western blotting.

Results:IL-21 exerted different effects on LPS-mediated inflammatory responses in various derived MΦs, and inhibited macrophages polarisation to M1-like macrophages and promote their polarisation to M2-like macrophages in HD and RA. Moreover, IL-21 inhibited LPS-mediated secretion of inflammatory cytokines, probably by downregulating the ERK1/2, in RA-SF MΦs.

Conclusion:For the first time, we indicated that IL-21 inhibits LPS-mediated cytokine production in RA-SF MΦs, and impairs pro-inflammatory activity of M1-like macrophages, hereby exerting anti-inflammatory effects on RA. Thus, IL-21 might not be an appropriate therapeutic target for RA.

Ethical approval

This study was reviewed and approved by the Peking University Third Hospital Ethics Committee (protocol no. IRB00006761-2015044) and informed consent was obtained from all patients.

Author contributions

JZ conceived and designed the study. LJ performed the experiments, analysed the data and wrote the manuscript. CL, XW, LS and ZM provided the assistance with the experiments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 81571573].

Log in via your institution

Log in to Taylor & Francis Online

PDF download + Online access
  • 48 hours access to article PDF & online version
  • Article PDF can be downloaded
  • Article PDF can be printed
USD 65.00 Add to cart
* Local tax will be added as applicable

Related Research

People also read lists articles that other readers of this article have read.

Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine.

Cited by lists all citing articles based on Crossref citations.
Articles with the Crossref icon will open in a new tab.