FANCC deficiency mediates microglial pyroptosis and secondary neuronal apoptosis in spinal cord contusion

Mingjie Xia; Xinyu Li; Suhui Ye; Qinyang Zhang; Tianyu Zhao; Rulin Li; Yanan Zhang; Minghan Xian; Tianqi Li; Haijun Li; Xin Hong; Shengnai Zheng; Zhanyang Qian; Lei Yang

doi:10.1186/s13578-022-00816-4

FANCC deficiency mediates microglial pyroptosis and secondary neuronal apoptosis in spinal cord contusion

Cell Biosci. 2022 Jun 3;12(1):82. doi: 10.1186/s13578-022-00816-4.

Authors

Mingjie Xia^#¹, Xinyu Li^#², Suhui Ye^#^{3

4}, Qinyang Zhang^{5

6}, Tianyu Zhao^{5

6}, Rulin Li^{5

6}, Yanan Zhang^{5

6}, Minghan Xian^{5

6}, Tianqi Li^{5

6}, Haijun Li⁶, Xin Hong^{3

4}, Shengnai Zheng⁷, Zhanyang Qian^{8

9}, Lei Yang^{10

11}

Affiliations

¹ Department of Orthopedics, Nanjing First Hospital, Nanjing Medical University, 68 Changle Road, Nanjing, 210029, Jiangsu, China.
² School of Health Economics Management, Nanjing University of Chinese Medicine, Nanjing, China.
³ Spine Center, Zhongda Hospital of Southeast University, Nanjing, China.
⁴ School of Medicine, Southeast University, Nanjing, China.
⁵ Postgraduate School, Dalian Medical University, Dalian, China.
⁶ Department of Orthopedics, Taizhou People's Hospital, Nanjing Medical University, No. 366 Taihu Road, Taizhou, 225300, Jiangsu, China.
⁷ Department of Orthopedics, Nanjing First Hospital, Nanjing Medical University, 68 Changle Road, Nanjing, 210029, Jiangsu, China. zsn3280@sina.com.
⁸ Spine Center, Zhongda Hospital of Southeast University, Nanjing, China. spineqzy@126.com.
⁹ School of Medicine, Southeast University, Nanjing, China. spineqzy@126.com.
¹⁰ Department of Orthopedics, Taizhou People's Hospital, Nanjing Medical University, No. 366 Taihu Road, Taizhou, 225300, Jiangsu, China. leiyang@njmu.edu.cn.
¹¹ School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing, China. leiyang@njmu.edu.cn.

^# Contributed equally.

Abstract

Background: Traumatic spinal cord injury (SCI)-induced neuroinflammation results in secondary neurological destruction and functional disorder. Previous findings showed that microglial pyroptosis plays a crucial role in neuroinflammation. Thus, it is necessary to conduct a comprehensive investigation of the mechanisms associated with post-SCI microglial pyroptosis. The Fanconi Anemia Group C complementation group gene (FANCC) has been previously reported to have an anti-inflammation effect; however, whether it can regulate microglial pyroptosis remains unknown. Therefore, we probed the mechanism associated with FANCC-mediated microglial pyroptosis and neuroinflammation in vitro and in vivo in SCI mice.

Methods: Microglial pyroptosis was assessed by western blotting (WB) and immunofluorescence (IF), whereas microglial-induced neuroinflammation was evaluated by WB, Enzyme-linked immunosorbent assays and IF. Besides, flow cytometry, TdT-mediated dUTP Nick-End Labeling staining and WB were employed to examine the level of neuronal apoptosis. Morphological changes in neurons were assessed by hematoxylin-eosin and Luxol Fast Blue staining. Finally, locomotor function rehabilitation was analyzed using the Basso Mouse Scale and Louisville Swim Scale.

Results: Overexpression of FANCC suppressed microglial pyroptosis via inhibiting p38/NLRP3 expression, which in turn reduced neuronal apoptosis. By contrast, knockdown of FANCC increased the degree of neuronal apoptosis by aggravating microglial pyroptosis. Besides, increased glial scar formation, severe myelin sheath destruction and poor axon outgrowth were observed in the mice transfected with short hairpin RNA of FANCC post SCI, which caused reduced locomotor function recovery.

Conclusions: Taken together, a previously unknown role of FANCC was identified in SCI, where its deficiency led to microglia pyroptosis, neuronal apoptosis and neurological damage. Mechanistically, FANCC mediated microglia pyroptosis and the inflammatory response via regulating the p38/NLRP3 pathway.

Keywords: FANCC; Microglia; NLRP3; Neuronal apoptosis; Pyroptosis; Spinal cord injury.