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Depolarization and Hyperexcitability of Cortical Motor Neurons after Spinal Cord Injury Associates with Reduced HCN Channel Activity. Int J Mol Sci 2023; 24:ijms24054715. [PMID: 36902146 PMCID: PMC10003573 DOI: 10.3390/ijms24054715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/05/2023] Open
Abstract
A spinal cord injury (SCI) damages the axonal projections of neurons residing in the neocortex. This axotomy changes cortical excitability and results in dysfunctional activity and output of infragranular cortical layers. Thus, addressing cortical pathophysiology after SCI will be instrumental in promoting recovery. However, the cellular and molecular mechanisms of cortical dysfunction after SCI are poorly resolved. In this study, we determined that the principal neurons of the primary motor cortex layer V (M1LV), those suffering from axotomy upon SCI, become hyperexcitable following injury. Therefore, we questioned the role of hyperpolarization cyclic nucleotide gated channels (HCN channels) in this context. Patch clamp experiments on axotomized M1LV neurons and acute pharmacological manipulation of HCN channels allowed us to resolve a dysfunctional mechanism controlling intrinsic neuronal excitability one week after SCI. Some axotomized M1LV neurons became excessively depolarized. In those cells, the HCN channels were less active and less relevant to control neuronal excitability because the membrane potential exceeded the window of HCN channel activation. Care should be taken when manipulating HCN channels pharmacologically after SCI. Even though the dysfunction of HCN channels partakes in the pathophysiology of axotomized M1LV neurons, their dysfunctional contribution varies remarkably between neurons and combines with other pathophysiological mechanisms.
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Silva Santos Ribeiro P, Willemen HLDM, Eijkelkamp N. Mitochondria and sensory processing in inflammatory and neuropathic pain. FRONTIERS IN PAIN RESEARCH (LAUSANNE, SWITZERLAND) 2022; 3:1013577. [PMID: 36324872 PMCID: PMC9619239 DOI: 10.3389/fpain.2022.1013577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 09/26/2022] [Indexed: 01/24/2023]
Abstract
Rheumatic diseases, such as osteoarthritis and rheumatoid arthritis, affect over 750 million people worldwide and contribute to approximately 40% of chronic pain cases. Inflammation and tissue damage contribute to pain in rheumatic diseases, but pain often persists even when inflammation/damage is resolved. Mechanisms that cause this persistent pain are still unclear. Mitochondria are essential for a myriad of cellular processes and regulate neuronal functions. Mitochondrial dysfunction has been implicated in multiple neurological disorders, but its role in sensory processing and pain in rheumatic diseases is relatively unexplored. This review provides a comprehensive understanding of how mitochondrial dysfunction connects inflammation and damage-associated pathways to neuronal sensitization and persistent pain. To provide an overall framework on how mitochondria control pain, we explored recent evidence in inflammatory and neuropathic pain conditions. Mitochondria have intrinsic quality control mechanisms to prevent functional deficits and cellular damage. We will discuss the link between neuronal activity, mitochondrial dysfunction and chronic pain. Lastly, pharmacological strategies aimed at reestablishing mitochondrial functions or boosting mitochondrial dynamics as therapeutic interventions for chronic pain are discussed. The evidence presented in this review shows that mitochondria dysfunction may play a role in rheumatic pain. The dysfunction is not restricted to neuronal cells in the peripheral and central nervous system, but also includes blood cells and cells at the joint level that may affect pain pathways indirectly. Pre-clinical and clinical data suggest that modulation of mitochondrial functions can be used to attenuate or eliminate pain, which could be beneficial for multiple rheumatic diseases.
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Walters MC, Ladle DR. Calcium Homeostasis in Parvalbumin DRG Neurons is Altered After Sciatic Nerve Crush and Sciatic Nerve Transection Injuries. J Neurophysiol 2021; 126:1948-1958. [PMID: 34758279 DOI: 10.1152/jn.00707.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Reflex abnormalities mediated by proprioceptive sensory neurons after peripheral nerve injury (PNI) can limit functional improvement, leaving patients with disability that affects their quality of life. We examined post-injury calcium transients in a subpopulation of DRG neurons consisting primarily of proprioceptors to determine whether alterations in calcium homeostasis are present in proprioceptors, as has been documented in other DRG neurons after PNI. Using transgenic mice, we restricted expression of the calcium indicator GCaMP6s to DRG neurons containing parvalbumin (PV). Mice of both sexes were randomly assigned to sham, sciatic nerve crush, or sciatic nerve transection and resuture conditions. Calcium transients were recorded from ex-vivo preparations of animals at one of three post-surgery time points: 1-3 days, 7-11 days, and after 60 days of recovery. Results demonstrated that the post-PNI calcium transients of PV DRG neurons are significantly different than sham. Abnormalities were not present during the acute response to injury (1-3 days), but transients were significantly different than sham at the recovery stage where axon regeneration is thought to be underway (7-11 days). During late-stage recovery (60 days post-injury), disturbances in the decay time course of calcium transients in transection animals persisted, whereas parameters of transients from crush animals returned to normal. These findings identify a deficit in calcium homeostasis in proprioceptive neurons, which may contribute to the failure to fully recover proprioceptive reflexes after PNI. Significant differences in the calcium transients of crush versus transection animals after reinnervation illustrate calcium homeostasis alterations are distinctive to injury type.
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Affiliation(s)
- Marie C Walters
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, United States
| | - David R Ladle
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, United States
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Yao X, Qian Y, Fan C. Electroactive nanomaterials in the peripheral nerve regeneration. J Mater Chem B 2021; 9:6958-6972. [PMID: 34195746 DOI: 10.1039/d1tb00686j] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Severe peripheral nerve injuries are threatening the life quality of human beings. Current clinical treatments contain some limitations and therefore extensive research and efforts are geared towards tissue engineering approaches and development. The biophysical and biochemical characteristics of nanomaterials are highly focused on as critical elements in the design and fabrication of regenerative scaffolds. Recent studies indicate that the electrical properties and nanostructure of biomaterials can significantly affect the progress of nerve repair. More importantly, these studies also demonstrate the fact that electroactive nanomaterials have substantial implications for regulating the viability and fate of primary supporting cells in nerve regeneration. In this review, we summarize the current knowledge of electroconductive and piezoelectric nanomaterials. We exemplify typical cellular responses through cell-material interfaces, and the nanomaterial-induced microenvironment rebalance in terms of several key factors, immune responses, angiogenesis and oxidative stress. This work highlights the mechanism and application of electroactive nanomaterials to the development of regenerative scaffolds for peripheral nerve tissue engineering.
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Affiliation(s)
- Xiangyun Yao
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
| | - Yun Qian
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
| | - Cunyi Fan
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
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Rysted JE, Lin Z, Walters GC, Rauckhorst AJ, Noterman M, Liu G, Taylor EB, Strack S, Usachev YM. Distinct properties of Ca 2+ efflux from brain, heart and liver mitochondria: The effects of Na +, Li + and the mitochondrial Na +/Ca 2+ exchange inhibitor CGP37157. Cell Calcium 2021; 96:102382. [PMID: 33684833 DOI: 10.1016/j.ceca.2021.102382] [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: 11/18/2020] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 10/22/2022]
Abstract
Mitochondrial Ca2+ transport is essential for regulating cell bioenergetics, Ca2+ signaling and cell death. Mitochondria accumulate Ca2+ via the mitochondrial Ca2+ uniporter (MCU), whereas Ca2+ is extruded by the mitochondrial Na+/Ca2+ (mtNCX) and H+/Ca2+ exchangers. The balance between these processes is essential for preventing toxic mitochondrial Ca2+ overload. Recent work demonstrated that MCU activity varies significantly among tissues, likely reflecting tissue-specific Ca2+ signaling and energy needs. It is less clear whether this diversity in MCU activity is matched by tissue-specific diversity in mitochondrial Ca2+ extrusion. Here we compared properties of mitochondrial Ca2+ extrusion in three tissues with prominent mitochondria function: brain, heart and liver. At the transcript level, expression of the Na+/Ca2+/Li+ exchanger (NCLX), which has been proposed to mediate mtNCX transport, was significantly greater in liver than in brain or heart. At the functional level, Na+ robustly activated Ca2+ efflux from brain and heart mitochondria, but not from liver mitochondria. The mtNCX inhibitor CGP37157 blocked Ca2+ efflux from brain and heart mitochondria but had no effect in liver mitochondria. Replacement of Na+ with Li+ to test the involvement of NCLX, resulted in a slowing of mitochondrial Ca2+ efflux by ∼70 %. Collectively, our findings suggest that mtNCX is responsible for Ca2+ extrusion from the mitochondria of the brain and heart, but plays only a small, if any, role in mitochondria of the liver. They also reveal that Li+ is significantly less effective than Na+ in driving mitochondrial Ca2+ efflux.
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Affiliation(s)
- Jacob E Rysted
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Zhihong Lin
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Grant C Walters
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Adam J Rauckhorst
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Maria Noterman
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Guanghao Liu
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Eric B Taylor
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Yuriy M Usachev
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa College of Medicine, Iowa City, IA, 52242, USA.
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Khuankaew C, Sawaddiruk P, Surinkaew P, Chattipakorn N, Chattipakorn SC. Possible roles of mitochondrial dysfunction in neuropathy. Int J Neurosci 2020; 131:1019-1041. [PMID: 32393100 DOI: 10.1080/00207454.2020.1765777] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
OBJECTIVES The present review aims to present and discuss the consistent and inconsistent evidence regarding the associations between mitochondrial dysfunction and several neuropathic models, including trauma-induced, chemotherapy-induced, diabetes-induced and HIV-associated sensory neuropathy. METHODS The searching strategy and inclusion criteria for this review are all research articles in the PubMed database published before July 2019. We used the search terms 'mitochondria' and 'neuropathy' for the present review and non-English articles were excluded. RESULTS Damage to mitochondria via trauma, chemotherapy drugs, hyperglycaemia and HIV infection has been widely discussed to play an important role in the pathogenesis of neuropathy. Several mechanisms of mitochondrial damages have been proposed. CONCLUSION The damage of mitochondria results in cellular apoptosis, which appears to be one of the key factors in the pathogenesis of neuropathy. Novel therapeutic strategies targeting mitochondria could be a potential therapeutic target in neuropathy.
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Affiliation(s)
- Chutikorn Khuankaew
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.,Department of Dentistry, Uttaradit Hospital, Uttaradit, Thailand
| | - Passakorn Sawaddiruk
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Department of Anesthesiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Poomarin Surinkaew
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Department of Anesthesiology, Lamphun Hospital, Lamphun, Thailand
| | - Nipon Chattipakorn
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Siriporn C Chattipakorn
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
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Intrathecal Injection of miR-133b-3p or miR-143-3p Prevents the Development of Persistent Cold and Mechanical Allodynia Following a Peripheral Nerve Injury in Rats. Neuroscience 2018; 386:223-239. [PMID: 30018017 DOI: 10.1016/j.neuroscience.2018.06.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 06/01/2018] [Accepted: 06/24/2018] [Indexed: 12/24/2022]
Abstract
In DRG an increase in miR-133b-3p, miR-143-3p, and miR-1-3p correlates with the lack of development of neuropathic pain following a peripheral nerve injury. Using lentiviral (LV) vectors we found that a single injection of LV-miR-133b-3p or LV-miR-143-3p immediately after a peripheral nerve injury prevented the development of sustained mechanical and cold allodynia. Injection of LV-miR-133b-3p or LV-miR-143-3p by themselves or in combination, on day 3 post-injury produced a partial and transient reduction in mechanical allodynia and a sustained decrease in cold allodynia. Injection of LV-miR-1-3p has no effect. Co-injection of LV-miR-1a with miR-133b-3p or miR-143-3p on day 3 post-injury produced a sustained decrease in mechanical and cold allodynia. In DRG cultures, miR-133b-3p and miR-143-3p but not miR-1-3p, enhanced the depolarization-evoked cytoplasmic calcium increase. Using 3'UTR target clones containing a Gaussian luciferase reporter gene we found that with the 3'UTR-Scn2b, miR-133-3p and miR-143-3p reduced the expression while miR-1-3p enhanced the expression of the reporter gene. With the 3'UTR-TRPM8, miR-133-3p and miR-143-3p reduced the expression and miR-1-3p had no effect. With the 3'UTR-Piezo2, miR-133-3p increased the expression while miR-143-3p and miR-1-3p had no effect. LV-miR133b-3p, LV-miR-143-3p and LV-miR1a-3p reduced Scn2b-mRNA and Piezo2-mRNA. LV-miR133b-3p and LV-miR-143-3p reduced TRPM8-mRNA. LV-miR-133b-3p and LV-miR-143-3p prevent the development of chronic pain when injected immediately after the injury, but are only partially effective when injected at later times. LV-miR-1a-3p had no effect on pain, but complemented the actions of LV-miR-133b-3p or LV-miR-143-3p resulting in a sustained reversal of pain when co-injected 3 days following nerve injury.
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Yilmaz E, Watkins SC, Gold MS. Paclitaxel-induced increase in mitochondrial volume mediates dysregulation of intracellular Ca 2+ in putative nociceptive glabrous skin neurons from the rat. Cell Calcium 2017; 62:16-28. [PMID: 28109678 DOI: 10.1016/j.ceca.2017.01.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 01/14/2023]
Abstract
We have recently demonstrated that in a rat model of chemotherapy-induced peripheral neuropathy (CIPN), there is a significant decrease in the duration of the depolarization-evoked Ca2+ transient in small diameter, IB4+, and capsaicin-responsive neurons innervating the glabrous skin of the hindpaw. This change was specific to the transient duration and significantly smaller if not undetectable in neurons innervating the dorsal skin of the hindpaw or the skin of the inner thigh. Given the importance of mitochondria in intracellular Ca2+ regulation and the findings of chemotherapy-associated increase in mitotoxicity along the sensory neuron axons, we hypothesized that CIPN is due to both increases and decreases in mitochondria function, with changes manifest in distinct subpopulations of afferents. To begin to test this hypothesis, we used confocal microscopy and Ca2+ imaging in combination with pharmacological manipulations to study paclitaxel-induced changes in retrograde tracer-labeled neurons from naïve, vehicle-treated, and paclitaxel-treated rats. Paclitaxel treatment was not associated with decreased mitochondrial membrane potential or increased superoxide levels in the somata of putative nociceptive glabrous skin neurons. However, it was associated with significant increases in the relative contribution of mitochondria to the control of the evoked Ca2+ transient duration in putative nociceptive glabrous skin neurons, as well as increases in mitotracker and Tom20 staining which reflected an increase in mitochondrial volume. Furthermore, the relative contribution of the sarco-endoplasmic reticulum Ca2+ ATPase to the regulation of the duration of the depolarization evoked Ca2+ transient was also increased in this subpopulation of neurons from paclitaxel treated rats. Our results indicate that the paclitaxel-induced decrease in the duration of the evoked Ca2+ transient is due to both direct and indirect influences of mitochondria. It remains to be determined if and how these changes contribute to the manifestation of CIPN.
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Affiliation(s)
- Eser Yilmaz
- Center for Neuroscience University of Pittsburgh, United States; Departments of Neurobiology, University of Pittsburgh School of Medicine, United States
| | - Simon C Watkins
- Cell Biology, University of Pittsburgh School of Medicine, United States; Immunology, University of Pittsburgh School of Medicine, United States
| | - Michael S Gold
- Center for Neuroscience University of Pittsburgh, United States; Departments of Neurobiology, University of Pittsburgh School of Medicine, United States.
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Sciatic nerve ligation causes impairment of mitochondria associated with changes in distribution, respiration, and cardiolipin composition in related spinal cord neurons in rats. Mol Cell Biochem 2016; 421:41-54. [DOI: 10.1007/s11010-016-2782-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 08/05/2016] [Indexed: 01/01/2023]
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