1. Academic Validation
  2. Chicken cathelicidin-2 promotes NLRP3 inflammasome activation in macrophages

Chicken cathelicidin-2 promotes NLRP3 inflammasome activation in macrophages

  • Vet Res. 2022 Sep 5;53(1):69. doi: 10.1186/s13567-022-01083-4.
Lianci Peng  # 1 Hongliang Tian  # 1 Yi Lu 1 Kaixiang Jia 1 Jinrong Ran 1 Qi Tao 1 Gang Li 1 Chao Wan 1 Chao Ye 1 Edwin J A Veldhuizen 2 Hongwei Chen 3 Rendong Fang 4 5
Affiliations

Affiliations

  • 1 Joint International Research Laboratory of Animal Health and Animal Food Safety, College of Veterinary Medicine, Southwest University, Chongqing, 400715, China.
  • 2 Department of Biomolecular Health Sciences, Division Infectious Diseases & Immunology, Section Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
  • 3 Joint International Research Laboratory of Animal Health and Animal Food Safety, College of Veterinary Medicine, Southwest University, Chongqing, 400715, China. [email protected].
  • 4 Joint International Research Laboratory of Animal Health and Animal Food Safety, College of Veterinary Medicine, Southwest University, Chongqing, 400715, China. [email protected].
  • 5 Immunology Research Center, Institute of Medical Research, Southwest University, Chongqing, 402460, China. [email protected].
  • # Contributed equally.
Abstract

Chicken cathelicidin-2 (CATH-2) as a host defense peptide has been identified to have potent antimicrobial and immunomodulatory activities. Here, we reported the mechanism by which CATH-2 modulates NLRP3 inflammasome activation. Our results show that CATH-2 and ATP as a positive control induced secretion of IL-1β and IL-1α in LPS-primed macrophages but did not affect secretion of IL-6, IL-12 and TNF-α. Furthermore, CATH-2 induced Caspase-1 activation and oligomerization of apoptosis-associated speck-like protein containing a carboxy- terminal Caspase recruitment domain (ASC), which is essential for NLRP3 inflammasome activation. However, CATH-2 failed to induce IL-1β secretion in Nlrp3-/-, Asc-/- and Casp1-/- macrophages. Notably, IL-1β and NLRP3 mRNA expression were not affected by CATH-2. In addition, CATH-2-induced NLRP3 inflammasome activation was mediated by K+ efflux but independent of the P2X7 receptor that is required for ATP-mediated K+ efflux. Gene interference of NEK7 kinase which has been identified to directly interact with NLRP3, significantly reduced IL-1β secretion and Caspase-1 activation induced by CATH-2. Furthermore, confocal microscopy shows that CATH-2 significantly induced lysosomal leakage with the diffusion of dextran fluorescent signal. Cathepsin B inhibitors completely abrogated IL-1β secretion and Caspase-1 activation as well as attenuating the formation of ASC specks induced by CATH-2. These results all indicate that CATH-2-induced activation of NLRP3 inflammasome is mediated by K+ efflux, and involves the NEK7 protein and Cathepsin B. In conclusion, our study shows that CATH-2 acts as a second signal to activate NLRP3 inflammasome. Our study provides new insight into CATH-2 modulating immune response.

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