Dong Li1,2, Shu-Zhuo Zhang1, Yu-Hong Yao3, Yun Xiang4, Xiao-Yun Ma1, Xiao-Li Wei1, Hai-Tao Yan1, Xiao-Yan Liu1. 1. Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China. 2. Department of Surgery, Hospital of 73096 Troop of PLA, Nanjing, Jiangsu, China. 3. State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. 4. Training bases, Hunan Key Laboratory of Chinese Materia Medical Power and Innovative Drugs Established by Provincial and Ministry, Hunan University of Chinese Medicine, Changsha, China.
Abstract
INTRODUCTION: Sigma-1 receptors (Sig-1Rs) are unique endoplasmic reticulum proteins that have been implicated in both neurodegenerative and ischemic diseases, such as Alzheimer's disease and stroke. Accumulating evidence has suggested that Sig-1R plays a role in neuroprotection and axon outgrowth. The underlying mechanisms of Sig-1R-mediated neuroprotection have been well elucidated. However, the mechanisms underlying the effects of Sig-1R on axon outgrowth are not fully understood. METHODS: To clarify this issue, we utilized immunofluorescence to compare the axon lengths of cultured naïve hippocampal neurons before and after the application of the Sig-1R agonist, SA4503. Then, electrophysiology and immunofluorescence were used to examine voltage-gated calcium ion channel (VGCCs) currents in the cell membranes and growth cones. RESULTS: We found that Sig-1R activation dramatically enhanced the axonal length of the naïve hippocampal neurons. Application of the Sig-1R antagonist NE100 and gene knockdown techniques both demonstrated the effects of Sig-1R. The growth-promoting effect of SA4503 was accompanied by the inhibition of voltage-gated Ca2+ influx and was recapitulated by incubating the neurons with the L-type, N-type, and P/Q-type VGCC blockers, nimodipine, MVIIA and ω-agatoxin IVA, respectively. This effect was unrelated to glial cells. The application of SA4503 transformed the growth cone morphologies from complicated to simple, which favored axon outgrowth. CONCLUSION: Sig-1R activation can enhance axon outgrowth and may have a substantial influence on neurogenesis and neurodegenerative diseases.
INTRODUCTION: Sigma-1 receptors (Sig-1Rs) are unique endoplasmic reticulum proteins that have been implicated in both neurodegenerative and ischemic diseases, such as Alzheimer's disease and stroke. Accumulating evidence has suggested that Sig-1R plays a role in neuroprotection and axon outgrowth. The underlying mechanisms of Sig-1R-mediated neuroprotection have been well elucidated. However, the mechanisms underlying the effects of Sig-1R on axon outgrowth are not fully understood. METHODS: To clarify this issue, we utilized immunofluorescence to compare the axon lengths of cultured naïve hippocampal neurons before and after the application of the Sig-1R agonist, SA4503. Then, electrophysiology and immunofluorescence were used to examine voltage-gated calcium ion channel (VGCCs) currents in the cell membranes and growth cones. RESULTS: We found that Sig-1R activation dramatically enhanced the axonal length of the naïve hippocampal neurons. Application of the Sig-1R antagonist NE100 and gene knockdown techniques both demonstrated the effects of Sig-1R. The growth-promoting effect of SA4503 was accompanied by the inhibition of voltage-gated Ca2+ influx and was recapitulated by incubating the neurons with the L-type, N-type, and P/Q-type VGCC blockers, nimodipine, MVIIA and ω-agatoxin IVA, respectively. This effect was unrelated to glial cells. The application of SA4503 transformed the growth cone morphologies from complicated to simple, which favored axon outgrowth. CONCLUSION:Sig-1R activation can enhance axon outgrowth and may have a substantial influence on neurogenesis and neurodegenerative diseases.
Authors: Antonino N Fallica; Valeria Pittalà; Maria N Modica; Loredana Salerno; Giuseppe Romeo; Agostino Marrazzo; Mohamed A Helal; Sebastiano Intagliata Journal: J Med Chem Date: 2021-06-02 Impact factor: 7.446