Established Stem Cell Model of Spinal Muscular Atrophy Is Applicable in the Evaluation of the Efficacy of Thyrotropin-Releasing Hormone Analog.

Abstract

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterized by the degeneration of spinal motor neurons. This disease is mainly caused by mutation or deletion of the survival motor neuron 1 (SMN1) gene. Currently, no effective treatment is available, and only symptomatic treatment can be provided. Our purpose in the present study was to establish a human SMA-derived induced pluripotent stem cell (SMA-iPSC) disease model and assay a therapeutic drug in preparation for the development of a novel treatment of SMA. We generated iPSCs from the skin fibroblasts of a patient with SMA and confirmed that they were pluripotent and undifferentiated. The neural differentiation of SMA-iPSCs shortened the dendrite and axon length and increased the apoptosis of the spinal motor neurons. In addition, we found activated astrocytes in differentiated SMA-iPSCs. Using this model, we confirmed that treatment with the thyrotropin-releasing hormone (TRH) analog, 5-oxo-l-prolyl-l-histidyl-l-prolinamide, which had marginal effects in clinical trials, increases the SMN protein level. This increase was mediated through the transcriptional activation of the SMN2 gene and inhibition of glycogen synthase kinase-3β activity. Finally, the TRH analog treatment resulted in dendrite and axon development of spinal motor neurons in differentiated SMA-iPSCs. These results suggest that this human in vitro disease model stimulates SMA pathology and reveal the potential efficacy of TRH analog treatment for SMA. Therefore, we can screen novel therapeutic drugs such as TRH for SMA easily and effectively using the human SMA-iPSC model. Significance: Platelet-derived growth factor (PDGF) has recently been reported to produce the greatest increase in survival motor neuron protein levels by inhibiting glycogen synthase kinase (GSK)-3β; however, motor neurons lack PDGF receptors. A human in vitro spinal muscular atrophy-derived induced pluripotent stem cell model was established, which showed that the thyrotropin releasing hormone (TRH) analog promoted transcriptional activation of the SMN2 gene and inhibition of GSK-3β activity, resulting in the increase and stabilization of the SMN protein and axon elongation of spinal motor neurons. These results reveal the potential efficacy of TRH analog treatment for SMA.

• Authors: Kazuki Ohuchi, Michinori Funato, Zenichiro Kato, Junko Seki, Chizuru Kawase, Yuya Tamai, Yoko Ono, Yuki Nagahara, Yasuhiro Noda, Tsubasa Kameyama, Shiori Ando, Kazuhiro Tsuruma, Masamitsu Shimazawa, Hideaki Hara, Hideo Kaneko
• Journal: Stem cells translational medicine (Stem Cells Transl Med) Vol. 5 Issue 2 Pg. 152-63 (Feb 2016) ISSN: 2157-6564 [Print] England
• PMID: 26683872 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: ©AlphaMed Press.

Chemical References

• SMN1 protein, human
• SMN2 protein, human
• Survival of Motor Neuron 1 Protein
• Survival of Motor Neuron 2 Protein
• 5-oxoprolyl-2,4(5)-diiodohistidyl-prolinamide
• Thyrotropin-Releasing Hormone
• GSK3B protein, human
• Glycogen Synthase Kinase 3 beta
• Glycogen Synthase Kinase 3

Topics

• Apoptosis (drug effects)
• Astrocytes (drug effects, metabolism, pathology)
• Cell Differentiation (drug effects)
• Child, Preschool
• Female
• Fibroblasts (drug effects, metabolism, pathology)
• Gene Expression
• Glycogen Synthase Kinase 3 (antagonists & inhibitors, genetics, metabolism)
• Glycogen Synthase Kinase 3 beta
• Humans
• Induced Pluripotent Stem Cells (drug effects, metabolism, pathology)
• Models, Biological
• Motor Neurons (drug effects, metabolism, pathology)
• Muscular Atrophy, Spinal (drug therapy, genetics, metabolism, pathology)
• Primary Cell Culture
• Signal Transduction
• Skin (drug effects, metabolism, pathology)
• Spine (drug effects, metabolism, pathology)
• Survival of Motor Neuron 1 Protein (genetics, metabolism)
• Survival of Motor Neuron 2 Protein (agonists, genetics, metabolism)
• Thyrotropin-Releasing Hormone (analogs & derivatives, therapeutic use)
• Transcriptional Activation