LRRK2G2019S mutation induced microglia activation after iron removal by inhibiting autophagy associated proteins
10.3760/cma.j.cn115354-20230821-00071
- VernacularTitle:LRRK2G2019S位点突变通过抑制自噬相关蛋白诱发驱铁处理后小胶质细胞的活化
- Author:
Zheng LIU
1
;
Zijian ZHENG
;
Xinjie LIU
;
Cheng XUE
;
Xiao WU
;
Xinran ZHANG
;
Jianwei LI
;
Lixuan LU
;
Guohui LU
Author Information
1. 南昌大学第一附属医院神经外科，南昌 330006
- Keywords:
Microglia;
Neuroinflammation;
Iron chelation;
LRRK2;
Rab35
- From:
Chinese Journal of Neuromedicine
2023;22(11):1098-1110
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the effect of LRRK2G2019S mutation on activation of microglia after iron deprivation and its mechanism.Methods:(1) Microglia were differentiated from human induced pluripotent stem cells (IPSC) with the help of hematopoietic progenitor cells (HPC) and identified by immunofluorescent staining, and α-synuclein (α-syn) A53T mutant protein was obtained by protein purification technology. (2) Microglia were divided into control group, α-syn group, α-syn+ deferoxamine (DFO) group; phosphate buffer solution (PBS), 1 μmol/L purified α-syn A53T mutant protein, 1 μmol/L purified α-syn A53T mutant protein+30 mmol/L DFO were given respectively for 24 h. Fe 2+ concentration was detected by colorimetry, Rab35 protein expression was detected by Western blotting, intracellular reactive oxygen species (ROS) level was detected by flow cytometry, and interleukin-6 ( IL-6), tumor necrosis factor-α ( TNF-α) and transforming growth factor-β ( TGF-β) mRNA expressions were detected by real time-PCR (RT-PCR); microglia culture supernatant (MCS) in the 3 groups were transfered to SH-SY5Y cells, and SH-SY5Y cell apoptosis was detected by flow cytometry. (3) Bidirectional DNA sequencing was used to detect leucine rich repeat kinase 2 ( LRRK2) gene mutations in microglia treated with 1 μmol/L purified α-syn A53T mutant protein. Microglia were divided into control group, α-syn group and α-syn+GSK3357679A group, and treated with corresponding drugs for 24 h, respectively (LRRK2 inhibitor GSK3357679A concentration: 10 nmol/L), and LRRK2 protein expression was detected by Western blotting; microglia were divided into control group, α-syn group, α-syn+GSK3357679A, and α-syn+GSK3357679A+DFO group, and treated with corresponding drugs for 24 h, Rab35 protein expression was detected by Western blotting, intracellular ROS level was detected by flow cytometry, and IL-6, TNF-α and TGF-β mRNA expressions were detected by RT-PCR. (4) Microglia were divided into control group, α-syn group, α-syn+rapamycin (RAPA) group, and treated with corresponding drugs for 24 h (concentration of autophagy inducer RAPA: 50 nmol/L); protein expressions of Rab35, P62 and microtubule-associated protein light chain 3 II (LC3II) were detected by Western blotting; intracellular ROS level was detected by flow cytometry, and IL-6, TNF-α and TGF-β mRNA expressions were detected by RT-PCR. (5) Microglia were divided into control group, α-syn group, and α-syn+Rab35 group, and treated with corresponding drugs for 24 h (concentration of Rab35 overexpressed plasmids: 1 μg/mL); Rab35, P62, and LC3II protein expressions were detected by Western blotting; ROS level was detected by flow cytometry, and IL-6, TNF-α and TGF-β mRNA expressions were detected by RT-PCR. Results:(1) Immunofluorescent staining showed negative neuronal nuclei (NeuN) expression and positive ionized calcium-binding adapter molecule 1 (Iba1) expression in microglia, and high LRRK2 expression; PcDNA3.1-SNCA-A53T expression plasmid was constructed and α-syn A53T mutant protein was purified. (2) The Fe 2+ concentration in α-syn group was significantly higher than that in control group, and the Fe 2+ concentration in α-syn+DFO group was significantly lower than that in α-syn group ( P<0.05); the Rab35 protein and TGF-β mRNA expressions in control group, α-syn group and α-syn+DFO group were decreased successively, while the IL-6 and TNF-α mRNA expressions were increased successively, with significant differences ( P<0.05); ROS level and SH-SY5Y cell apoptosis rate in control group, α-syn group, α-syn+DFO group were increased successively. (3) Bidirectional DNA sequencing showed that the LRRK2G2019S mutation in microglia was the most obvious after α-syn A53T mutant protein stimulation; compared with the control group, the α-syn group had significantly increased LRRK2 protein expression, while the α-syn+GSK3357679A group had significantly decreased LRRK2 protein expression compared with α-syn group ( P<0.05); compared with the control group, the α-syn group had significantly decreased Rab35 protein and TGF-β mRNA expressions, and statistically increased IL-6 and TNF-α mRNA expressions ( P<0.05); compared with α-syn group, the α-syn+GSK3357679A group had significantly increased Rab35 protein and TGF-β mRNA expressions, and statistically decreased IL-6 and TNF-α mRNA expressions ( P<0.05); compared with α-syn+GSK3357679A group, α-syn+GSK3357679A+DFO group had significantly increased IL-6 and TNF-α mRNA expressions, and significantly decreased Rab35 protein and TGF-β mRNA expressions ( P<0.05). The α-syn group had higher ROS level than the control group, the α-syn+GSK3357679A group had lower ROS level than the α-syn group, and the α-syn+GSK3357679A+DFO group had higher ROS level than the α-syn+GSK3357679A group. (4) Compared with the control group, the α-syn group had significantly decreased Rab35 and LC3II protein, and TGF-β mRNA expressions, and significantly increased P62 protein, IL-6 and TNF-α mRNA expressions ( P<0.05); compared with α-syn group, the α-syn+RAPA group had significantly increased Rab35 and LC3II protein, and TGF-β mRNA expressions, and significantly decreased P62 protein, and IL-6 and TNF-α mRNA expressions ( P<0.05); the α-syn group had higher ROS level than the control group and α-syn+RAPA group. (5) Compared with the control group, the α-syn group had significantly decreased Rab35 and LC3II protein, and TGF-β mRNA expressions, and statistically increased P62 protein, and IL-6 and TNF-α mRNA expressions ( P<0.05); compared with the α-syn group, the α-syn+Rab35 group had significantly increased Rab35 and LC3II protein, and TGF-β mRNA expressions, and significantly decreased P62 protein, and IL-6 and TNF-α mRNA expressions ( P<0.05). The α-syn group had higher ROS level than the control group and α-syn+Rab35 group. Conclusion:LRRK2G2019S can induce neuroinflammation by inhibiting Rab35-related autophagy under iron deprivation, and Rab35 is expected to be a key factor in intervening neuroinflammation.
