C3a/C3aR synergies with TGF-β to promote epithelial-mesenchymal transition of renal tubular epithelial cells via the activation of the NLRP3 inflammasome

Danyu You; Kun Nie; Xiaoting Wu; Mengjie Weng; Liyan Yang; Yi Chen; Jiong Cui; Jianxin Wan

doi:10.1186/s12967-023-04764-6

C3a/C3aR synergies with TGF-β to promote epithelial-mesenchymal transition of renal tubular epithelial cells via the activation of the NLRP3 inflammasome

J Transl Med. 2023 Dec 11;21(1):904. doi: 10.1186/s12967-023-04764-6.

Authors

Danyu You^#^{1

2

3}, Kun Nie^#^{1

2

3}, Xiaoting Wu^{1

2

3}, Mengjie Weng^{1

2

3}, Liyan Yang^{1

2

3}, Yi Chen^{1

2

3}, Jiong Cui^{1

2

3}, Jianxin Wan^{4

5

6}

Affiliations

¹ Department of Nephrology, Blood Purification Research Center, The First Affiliated Hospital of Fujian Medical University, Chazhong Road 20, Fuzhou, 350005, China.
² Fujian Clinical Research Center for Metabolic Chronic Kidney Disease, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350005, China.
³ Department of Nephrology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, 350212, China.
⁴ Department of Nephrology, Blood Purification Research Center, The First Affiliated Hospital of Fujian Medical University, Chazhong Road 20, Fuzhou, 350005, China. wanjx@fjmu.edu.cn.
⁵ Fujian Clinical Research Center for Metabolic Chronic Kidney Disease, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350005, China. wanjx@fjmu.edu.cn.
⁶ Department of Nephrology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, 350212, China. wanjx@fjmu.edu.cn.

^# Contributed equally.

Abstract

Background: Complement component 3a and its receptor (C3a/C3aR) and the nucleotide-binding oligomerization domain-like receptor protein-3 (NLRP3) inflammasome contribute to epithelial-mesenchymal transition (EMT). However, the relationship between C3a/C3aR and the NLRP3 inflammasome in EMT remains unclear. This study aimed to elucidate the roles of C3a/C3aR and the NLRP3 inflammasome involved in TGF-β-induced EMT.

Method: Mouse renal tubular epithelial cells (TCMK-1) were exposed to C3a and TGF-β for 48 h. C3aR antagonist, MCC950, an inhibitor of the NLRP3 inflammasome and PD98059, an inhibitor of ERK signaling, were respectively applied to pretreat the cells at 30 min before C3a and TGF-β administration.The cells were collected for western blot, immunofluorescence staining and ELISA. Unilateral ureteral obstruction (UUO) models were established using male C57BL/6 wild-type (WT) mice and age-matched C3aR-deficient mice. MCC950 was intraperitoneally injected in UUO mice. Kidney samples were collected for immunohistochemistry staining.

Results: In vitro, C3a synergized with TGF-β to promote EMT and the activation of the NLRP3 inflammasome. Inhibition of C3aR attenuated EMT and the activation of the NLRP3 inflammasome. Inhibition of the NLRP3 inflammasome alleviated EMT but didn't affect the expression of C3aR. Inhibition of ERK signaling inhibited the activation of the NLRP3 inflammasome. In vivo, the expression of IL-1β was significantly higher in UUO mice compared to the sham-operated mice. C3aR deficiency and inhibition of the NLRP3 Inflammasome contributed to decreased IL-1β in UUO mice.

Conclusion: Our data revealed that C3a/C3aR synergies with TGF-β to activate the NLRP3 inflammasome to promote epithelial-mesenchymal transition of renal tubular epithelial cells through ERK signaling, and the way in which C3aR activates the inflammasome is to promote the assembly of the NLRP3 inflammasome.

Keywords: Complement component 3a receptor; Epithelial-mesenchymal transition; The NLRP3 inflammasome.

MeSH terms

Animals
Epithelial Cells / metabolism
Epithelial-Mesenchymal Transition
Fibrosis
Inflammasomes* / metabolism
Interleukin-1beta / metabolism
Male
Mice
Mice, Inbred C57BL
NLR Family, Pyrin Domain-Containing 3 Protein* / metabolism
Transforming Growth Factor beta

Substances

Inflammasomes
NLR Family, Pyrin Domain-Containing 3 Protein
Transforming Growth Factor beta
Interleukin-1beta