2. Academic Validation
  3. High-Frequency Repetitive Transcranial Magnetic Stimulation Mediates Autophagy Flux in Human Bone Mesenchymal Stromal Cells via NMDA Receptor-Ca2+-Extracellular Signal-Regulated Kinase-Mammalian Target of Rapamycin Signaling

High-Frequency Repetitive Transcranial Magnetic Stimulation Mediates Autophagy Flux in Human Bone Mesenchymal Stromal Cells via NMDA Receptor-Ca2+-Extracellular Signal-Regulated Kinase-Mammalian Target of Rapamycin Signaling

  • Front Neurosci. 2019 Nov 19;13:1225. doi: 10.3389/fnins.2019.01225.
Xinlong Wang 1,  Xing Zhou 1 2,  Jie Bao 3,  Zhiguo Chen 4,  Jingzhao Tang 1 5,  Xueyang Gong 1 6,  Jing Ni 1 7,  Qi Fang 4,  Yaobo Liu 8,  Min Su 1
Affiliations

Affiliations

  • 1 Department of Physical Medicine and Rehabilitation, The First Affiliated Hospital of Soochow University, Suzhou, China.
  • 2 Department of Children's Health Care Center, Wuxi Children's Hospital, Wuxi, China.
  • 3 Sport Rehabilitation Center of Physical and Education School, Soochow University, Suzhou, China.
  • 4 Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China.
  • 5 Department of Medical Rehabilitation, Community Health Service Center of Yangming Street, Wuxi, China.
  • 6 Department of Cardiopulmonary Rehabilitation, Wuxi Tongren Rehabilitation Hospital, Wuxi, China.
  • 7 Department of Geriatric Rehabilitation, Jiangsu Rongjun Hospital, Wuxi, China.
  • 8 Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, China.
PMID: 31798406 DOI: 10.3389/fnins.2019.01225
Abstract

Aim: Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive and safe technique for treatment of central and peripheral nerve injury. In recent years, this technique has been widely used in clinic, and an increasing number of studies have reported its mechanisms. In this study, we investigated the mechanisms of rTMS-mediated Autophagy flux in human bone mesenchymal stromal cells (BMSCs).

Methods: A frequency of 50 Hz was employed. Cells were divided into five groups: (1) normal, (2) sham, (3) 0.5 T, (4) 1.0 T, and (5) 1.5 T. Cells were stimulated for 20 min/day. The levels of p62, LC3-II/I, phosphorylated extracellular signal-regulated kinase (p-ERK), ERK, phosphorylated-AKT (p-AKT), Akt, phosphorylated mammalian target of rapamycin (p-mTOR), mTOR, phosphorylated protein kinase A (p-PKA), PKA, phosphorylated epidermal growth factor receptor (p-EGFR), EGFR, Nanog, Oct4, Sox2, and NMDA receptor (NMDAR1) were investigated by western blotting. Intracellular calcium (Ca2+) levels were quantified by flow cytometry. p62 and LC3 expression was also assessed by immunofluorescence analysis.

Results: In the 0.5 T group, rTMS increased the expression of LC3-II/I, p-ERK/ERK, and NMDAR1 and decreased the levels of p62 and p-mTOR/mTOR than in the normal group. The ratio of p-AKT/Akt, p-PKA/PKA, and p-EGFR/EGFR and the expression of Nanog, Oct4, and Sox2 remained unchanged. Immunofluorescence analysis revealed colocalization of p62 with LC3 puncta, and flow cytometry analysis displayed that Ca2+ levels were elevated. However, in the 1.0 and 1.5 T groups, no changes in the expression of these Autophagy markers were observed.

Conclusion: In the 0.5 T group, high-frequency rTMS can induce Autophagy through NMDAR-Ca2+-ERK-mTOR signaling in BMSCs. In the 1.0 and 1.5 T groups, Autophagy is not activated.

Keywords

NMDA receptor; autophagy; bone mesenchymal stromal cells; extracellular signal-regulated kinase–mammalian target of rapamycin signaling; repetitive transcranial magnetic stimulation.

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