Kangcheng Zhao1, Ran An2, Qian Xiang1, Gaocai Li1, Kun Wang1, Yu Song1, Zhiwei Liao1, Shuai Li1, Wenbin Hua1, Xiaobo Feng1, Xinghuo Wu1, Yukun Zhang1, Abhirup Das3,4, Cao Yang1. 1. Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China. 2. Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China. 3. SpineLabs, St George & Sutherland Clinical School, The University of New South Wales, Sydney, NSW, Australia. 4. Spine Service, Department of Orthopaedic Surgery, St George Hospital Campus, Sydney, NSW, Australia.
Abstract
OBJECTIVE: Lactate accumulation is an important factor in the intervertebral disc degeneration (IVDD). Currently, the effect and underlying mechanism of action of lactate on nucleus pulposus (NP) cell inflammation during IVDD are unclear. Previous studies have found that the NLRP3 inflammasome plays an important role in the regulation of NP inflammation. This study focused on the regulation of acid-sensitive ion channels (ASICs) in relation to inflammation and the effect of NLRP3 on pyroptosis levels in NP cells under acidic conditions. DESIGN: For the in vitro experiments, human NP cells were exposed to 6 mM lactate solution; different groups were either treated with NLRP3 inhibitor or transfected with siRNA against NLRP3, siRNA against ASC or a mix of these, and mRNA and protein expression levels were then assessed. For the in vivo experiment, varying concentrations of lactate were injected into rat intervertebral discs and examined via magnetic resonance imaging (MRI) and histological staining. RESULTS: Extracellular lactate promoted NLRP3 inflammasome activation and degeneration of the NP extracellular matrix; furthermore, it increased the levels of inflammation and pyroptosis in the NP. Lactate-induced NLRP3 inflammasome activation was blocked by ASIC inhibitors and NLRP3 siRNA. CONCLUSIONS: Extracellular lactate regulates levels of intercellular reactive oxygen species (ROS) through ASIC1 and ASIC3. ROS activate the NF-κB signalling pathway, thus promoting NLRP3 inflammasome activation and IL-1β release, both of which promote NP degeneration.
OBJECTIVE:Lactate accumulation is an important factor in the intervertebral disc degeneration (IVDD). Currently, the effect and underlying mechanism of action of lactate on nucleus pulposus (NP) cell inflammation during IVDD are unclear. Previous studies have found that the NLRP3 inflammasome plays an important role in the regulation of NPinflammation. This study focused on the regulation of acid-sensitive ion channels (ASICs) in relation to inflammation and the effect of NLRP3 on pyroptosis levels in NP cells under acidic conditions. DESIGN: For the in vitro experiments, humanNP cells were exposed to 6 mM lactate solution; different groups were either treated with NLRP3inhibitor or transfected with siRNA against NLRP3, siRNA against ASC or a mix of these, and mRNA and protein expression levels were then assessed. For the in vivo experiment, varying concentrations of lactate were injected into rat intervertebral discs and examined via magnetic resonance imaging (MRI) and histological staining. RESULTS: Extracellular lactate promoted NLRP3 inflammasome activation and degeneration of the NP extracellular matrix; furthermore, it increased the levels of inflammation and pyroptosis in the NP. Lactate-induced NLRP3 inflammasome activation was blocked by ASIC inhibitors and NLRP3 siRNA. CONCLUSIONS: Extracellular lactate regulates levels of intercellular reactive oxygen species (ROS) through ASIC1 and ASIC3. ROS activate the NF-κB signalling pathway, thus promoting NLRP3 inflammasome activation and IL-1β release, both of which promote NP degeneration.
Authors: Chenxia Juan; Ye Zhu; Yan Chen; Yan Mao; Yan Zhou; Weiwei Zhu; Xufang Wang; Qian Wang Journal: Bioengineered Date: 2022-05 Impact factor: 6.832