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Schmitt LI, David C, Steffen R, Hezel S, Roos A, Schara-Schmidt U, Kleinschnitz C, Leo M, Hagenacker T. Spinal astrocyte dysfunction drives motor neuron loss in late-onset spinal muscular atrophy. Acta Neuropathol 2023; 145:611-635. [PMID: 36930296 PMCID: PMC10119066 DOI: 10.1007/s00401-023-02554-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/01/2023] [Accepted: 03/01/2023] [Indexed: 03/18/2023]
Abstract
Spinal muscular atrophy (SMA) is a progressive neuromuscular disorder caused by a loss of the survival of motor neuron 1 (SMN1) gene, resulting in a loss of spinal motor neurons (MNs), leading to muscle weakness and wasting. The pathogenesis of MN loss in SMA and the selective vulnerability in different cellular populations are not fully understood. To investigate the role of spinal astrocytes in the pathogenesis of late-onset SMA, we used a mouse model in addition to in vitro approaches. Immunostaining, Western blot analysis, small interfering ribonucleic acid (siRNA) transfections, functional assays, enzyme-linked immunosorbent assay (ELISA), behavioral tests, and electrophysiological measurements were performed. Early activation of spinal astrocytes and a reduction of the excitatory amino acid transporter 1 (EAAT1) on postnatal day (P) 20 preceded the loss of spinal MNs in SMA mice occurring on P42. EAAT1 reduction resulted in elevated glutamate levels in the spinal cord of SMA mice at P20 and P42. SMA-like astrocytes generated by siRNA and an ex vivo model of glutamate excitotoxicity involving organotypic spinal cord slice cultures revealed the critical role of glutamate homeostasis in the degeneration of MNs. The pre-emptive administration of arundic acid (AA), as an inhibitor of astrocyte activation, to SMA mice prior to the loss of motor neurons (P28) resulted in elevated EAAT1 protein levels compared to vehicle-treated SMA mice and prevented the increase of glutamate in the spinal cord and the loss of spinal MNs. Furthermore, AA preserved motor functions during behavioral experiments, the electrophysiological properties, and muscle alteration of SMA mice. In a translational approach, we transfected healthy human fibroblasts with SMN1 siRNA, resulting in reduced EAAT1 expression and reduced uptake but increased glutamate release. These findings were verified by detecting elevated glutamate levels and reduced levels of EAAT1 in cerebrospinal fluid of untreated SMA type 2 and 3 patients. In addition, glutamate was elevated in serum samples, while EAAT1 was not detectable. Our data give evidence for the crucial role of spinal astrocytes in the pathogenesis of late-onset SMA, a potential driving force for MN loss by glutamate excitotoxicity caused by EAAT1 reduction as an early pathophysiological event. Furthermore, our study introduces EAAT1 as a potential therapeutic target for additional SMN-independent therapy strategies to complement SMN-enhancing drugs.
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Affiliation(s)
- Linda-Isabell Schmitt
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany.
| | - Christina David
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Rebecca Steffen
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Stefanie Hezel
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Andreas Roos
- Department of Pediatrics 1, Division of Neuropediatrics, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Ulrike Schara-Schmidt
- Department of Pediatrics 1, Division of Neuropediatrics, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Christoph Kleinschnitz
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Markus Leo
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Tim Hagenacker
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
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Induction of Survival of Motor Neuron (SMN) Protein Deficiency in Spinal Astrocytes by Small Interfering RNA as an In Vitro Model of Spinal Muscular Atrophy. Cells 2022; 11:cells11030558. [PMID: 35159369 PMCID: PMC8834238 DOI: 10.3390/cells11030558] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/31/2022] [Accepted: 02/03/2022] [Indexed: 02/05/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a motor neuron disorder leading to progressive loss of ventral horn neurons resulting in muscle wasting. Here we investigate the contribution of spinal astrocytes to the pathogenesis of late-onset SMA forms using a mouse model. Furthermore, we generated SMA-like astrocytes using survival of motor neuron (SMN) siRNA transfection techniques. In the SMA mouse model, the activation of spinal astrocytes and the reduction of the inward rectifier potassium channel Kir4.1 and excitatory amino acid transporter 1 (EAAT1) were observed at postnatal day (P) 28, preceding the loss of spinal motor neurons appearing earliest at P42. Using SMA-like astrocytes, we could mimic the modulation of spinal astrocytes of the mouse model in a dish and perform electrophysiological assessments and functional assays. In SMA-like astrocytes, glutamate uptake was diminished due to a reduction in EAAT1. Furthermore, patch-clamp measurements revealed reduced potassium uptake into astrocytes with membrane depolarization. Additionally, exposure of healthy spinal motor neurons to a conditioned medium of SMA-like astrocytes resulted in increased firing frequency. These data demonstrate spinal astrocytes’ crucial role in the late-onset SMA forms’ pathogenesis.
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Yang X, Dai Y, Ji Z, Zhang X, Fu W, Han C, Xu Y. Allium macrostemon Bunge. exerts analgesic activity by inhibiting NaV1.7 channel. JOURNAL OF ETHNOPHARMACOLOGY 2021; 281:114495. [PMID: 34364968 DOI: 10.1016/j.jep.2021.114495] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/01/2021] [Accepted: 08/04/2021] [Indexed: 06/13/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Allium macrostemon Bunge. is an edible Chinese herb traditionally used for the treatment of thoracic pain, stenocardia, heart asthma and diarrhea. Although its biological potential has been extensively proven such as antioxidant activity, antiplatelet aggregation, vasodilation and antidepressant-like activity, there are no reports in the literature regarding its pharmacological analgesic activity. AIM OF THE STUDY The study was carried out to examine the anti-nociceptive activity of the crude extract of A. macrostemon bulbs and interpret its likely molecular target. MATERIALS AND METHODS The bulbs of A. macrostemon were gathered, dried-up, and extracted with water (AMWD). AMWD was subjected to activity testing, using chemical-induced (acetic acid and formalin test) and heat-induced (hot plate) pain models. To evaluate the likely mechanistic strategy involved in the analgesic effect of AMWD, whole-cell patch clamp recordings were conducted in acutely dissociated dorsal root ganglion (DRG) neurons and human embryonic kidney 293T (HEK293T) cells expressing pain-related receptors. Electrophysiological methods were employed to detect the action potentials of DRG neurons and potential targets of A. macrostemon. RESULTS AMWD showed significant palliative effect in all heat and chemical induced pain assays. Moreover, AMWD significantly reduces the excitability of dorsal root ganglion neurons by reducing the firing frequency of action potentials. Further analysis revealed that voltage-gated sodium channel Nav1.7 is the potential target of A. macrostemon for its analgesic activity. CONCLUSION This study has brought new scientific evidence of preclinical efficacy of A. macrostemon as an anti-nociceptive agent. Apparently, these effects are involved with the inhibition of the voltage-sensitive Nav1.7 channel contributing to the reduction of peripheral neuronal excitability. Our present study justifies the folkloric usage of A. macrostemon as a remedy for several pain states. Furthermore, A. macrostemon is a good resource for the development of analgesic drugs targeting Nav1.7 channel.
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Affiliation(s)
- Xiaopei Yang
- Department of Basic Medicine, Chuxiong Medical College, Chuxiong, 675005, China.
| | - Yuwen Dai
- Department of Basic Medicine, Chuxiong Medical College, Chuxiong, 675005, China
| | - Zhilin Ji
- Department of Basic Medicine, Chuxiong Medical College, Chuxiong, 675005, China
| | - Xiangyi Zhang
- Department of Basic Medicine, Chuxiong Medical College, Chuxiong, 675005, China
| | - Wei Fu
- Department of Basic Medicine, Chuxiong Medical College, Chuxiong, 675005, China
| | - Chaochi Han
- Department of Basic Medicine, Chuxiong Medical College, Chuxiong, 675005, China
| | - Yunsheng Xu
- Department of Basic Medicine, Chuxiong Medical College, Chuxiong, 675005, China.
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Han X, Shao J, Ren X, Li Y, Yu W, Lin C, Li L, Sun Y, Xu B, Luo H, Zhu C, Cao J, Li Z. The different mechanisms of peripheral and central TLR4 on chronic postsurgical pain in rats. J Anat 2021; 239:111-124. [PMID: 33730389 PMCID: PMC8197940 DOI: 10.1111/joa.13406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 12/30/2022] Open
Abstract
Chronic postsurgical pain (CPSP) is a common complication after surgery; however, the underlying mechanisms of CPSP are poorly understood. As one of the most important inflammatory pathways, the Toll-like receptor 4/nuclear factor-kappa B (TLR4/NF-κB) signaling pathway plays an important role in chronic pain. However, the precise role of the TLR4/NF-κB signaling pathway in CPSP remains unclear. In the present study, we established a rat model of CPSP induced by skin/muscle incision and retraction (SMIR) and verified the effects and mechanisms of central and peripheral TLR4 and NF-κB on hyperalgesia in SMIR rats. The results showed that TLR4 expression was increased in both the spinal dorsal horn and dorsal root ganglia (DRGs) of SMIR rats. However, the TLR4 expression pattern in the spinal cord was different from that in DRGs. In the spinal cord, TLR4 was expressed in both neurons and microglia, whereas it was expressed in neurons but not in satellite glial cells in DRGs. Further results demonstrate that the central and peripheral TLR4/NF-κB signaling pathway is involved in the SMIR-induced CPSP by different mechanisms. In the peripheral nervous system, we revealed that the TLR4/NF-κB signaling pathway induced upregulation of voltage-gated sodium channel 1.7 (Nav1.7) in DRGs, triggering peripheral hyperalgesia in SMIR-induced CPSP. In the central nervous system, the TLR4/NF-κB signaling pathway participated in SMIR-induced CPSP by activating microglia in the spinal cord. Ultimately, our findings demonstrated that activation of the peripheral and central TLR4/NF-κB signaling pathway involved in the development of SMIR-induced CPSP.
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Affiliation(s)
- Xuemin Han
- The Second Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
- The First Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
- Children’s Hospital of Soochow UniversitySoochowChina
| | - Jinping Shao
- Department of Human AnatomySchool of Basic MedicineZhengzhou UniversityZhengzhouChina
- Institute of NeuroscienceZhengzhou UniversityZhengzhouChina
| | - Xiuhua Ren
- Department of Human AnatomySchool of Basic MedicineZhengzhou UniversityZhengzhouChina
- Institute of NeuroscienceZhengzhou UniversityZhengzhouChina
| | - Yaru Li
- The Second Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
- The First Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Wenli Yu
- Department of Human AnatomySchool of Basic MedicineZhengzhou UniversityZhengzhouChina
- Institute of NeuroscienceZhengzhou UniversityZhengzhouChina
| | - Caihong Lin
- Department of Human AnatomySchool of Basic MedicineZhengzhou UniversityZhengzhouChina
- Institute of NeuroscienceZhengzhou UniversityZhengzhouChina
| | - Lei Li
- Department of Human AnatomySchool of Basic MedicineZhengzhou UniversityZhengzhouChina
- Institute of NeuroscienceZhengzhou UniversityZhengzhouChina
| | - Yanyan Sun
- Department of Human AnatomySchool of Basic MedicineZhengzhou UniversityZhengzhouChina
- Institute of NeuroscienceZhengzhou UniversityZhengzhouChina
| | - Bo Xu
- Department of AnesthesiologyGeneral Hospital of Southern Theatre Command of PLAGuangzhouChina
| | - Huan Luo
- Klinik für AugenheilkundeCharité–Universitätsmedizin Berlin, corporate member of Freie Universität BerlinHumboldt‐Universität zu Berlin, and Berlin Institute of HealthGermany
| | - Changlian Zhu
- Center for Brain Repair and RehabilitationInstitute of Neuroscience and PhysiologyGothenburg UniversityGothenburgSweden
| | - Jing Cao
- Department of Human AnatomySchool of Basic MedicineZhengzhou UniversityZhengzhouChina
- Institute of NeuroscienceZhengzhou UniversityZhengzhouChina
| | - Zhisong Li
- The Second Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
- The First Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
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Kankowski S, Grothe C, Haastert-Talini K. Neuropathic pain: Spotlighting anatomy, experimental models, mechanisms, and therapeutic aspects. Eur J Neurosci 2021; 54:4475-4496. [PMID: 33942412 DOI: 10.1111/ejn.15266] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 04/19/2021] [Accepted: 04/28/2021] [Indexed: 12/30/2022]
Abstract
The International Association for the Study of Pain defines neuropathic pain as "pain arising as a direct consequence of a lesion or disease affecting the somatosensory system". The associated changes can be observed in the peripheral as well as the central nervous system. The available literature discusses a wide variety of causes as predisposing for the development and amplification of neuropathic pain. Further, key interactions within sensory pathways have been discovered, but no common molecular mechanism leading to neuropathic pain has been identified until now. In the first part of this review, the pain mediating lateral spinothalamic tract is described. Different in vivo models are presented that allow studying trauma-, chemotherapy-, virus-, and diabetes-induced neuropathic pain in rodents. We furthermore discuss approaches to assess neuropathic pain in these models. Second, the current knowledge about cellular and molecular mechanisms suggested to underlie the development of neuropathic pain is presented and discussed. A summary of established therapies that are already applied in the clinic and novel, promising approaches closes the paper. In conclusion, the established animal models are able to emulate the diversity of neuropathic pain observed in the clinics. However, the assessment of neuropathic pain in the presented in vivo models should be improved. The determination of common molecular markers with suitable in vitro models would simplify the assessment of neuropathic pain in vivo. This would furthermore provide insights into common molecular mechanisms of the disease and establish a basis to search for satisfying therapeutic approaches.
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Affiliation(s)
- Svenja Kankowski
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School (MHH), Hannover, Germany
| | - Claudia Grothe
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School (MHH), Hannover, Germany.,Center for Systems Neuroscience (ZNS) Hannover, Hannover, Germany
| | - Kirsten Haastert-Talini
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School (MHH), Hannover, Germany.,Center for Systems Neuroscience (ZNS) Hannover, Hannover, Germany
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