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Abstract
Neuropathic pain is a debilitating form of pain arising from injury or disease of the nervous system that affects millions of people worldwide. Despite its prevalence, the underlying mechanisms of neuropathic pain are still not fully understood. Dendritic spines are small protrusions on the surface of neurons that play an important role in synaptic transmission. Recent studies have shown that dendritic spines reorganize in the superficial and deeper laminae of the spinal cord dorsal horn with the development of neuropathic pain in multiple models of disease or injury. Given the importance of dendritic spines in synaptic transmission, it is possible that studying dendritic spines could lead to new therapeutic approaches for managing intractable pain. In this review article, we highlight the emergent role of dendritic spines in neuropathic pain, as well as discuss the potential for studying dendritic spines for the development of new therapeutics.
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Affiliation(s)
- Curtis A Benson
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Jared F King
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Marike L Reimer
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Sierra D Kauer
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Andrew M Tan
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
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Allahham A, Rowe G, Stevenson A, Fear MW, Vallence AM, Wood FM. The impact of burn injury on the central nervous system. BURNS & TRAUMA 2024; 12:tkad037. [PMID: 38312739 PMCID: PMC10835674 DOI: 10.1093/burnst/tkad037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/31/2023] [Accepted: 06/21/2023] [Indexed: 02/06/2024]
Abstract
Burn injuries can be devastating, with life-long impacts including an increased risk of hospitalization for a wide range of secondary morbidities. One area that remains not fully understood is the impact of burn trauma on the central nervous system (CNS). This review will outline the current findings on the physiological impact that burns have on the CNS and how this may contribute to the development of neural comorbidities including mental health conditions. This review highlights the damaging effects caused by burn injuries on the CNS, characterized by changes to metabolism, molecular damage to cells and their organelles, and disturbance to sensory, motor and cognitive functions in the CNS. This damage is likely initiated by the inflammatory response that accompanies burn injury, and it is often long-lasting. Treatments used to relieve the symptoms of damage to the CNS due to burn injury often target inflammatory pathways. However, there are non-invasive treatments for burn patients that target the functional and cognitive damage caused by the burn, including transcranial magnetic stimulation and virtual reality. Future research should focus on understanding the mechanisms that underpin the impact of a burn injury on the CNS, burn severity thresholds required to inflict damage to the CNS, and acute and long-term therapies to ameliorate deleterious CNS changes after a burn.
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Affiliation(s)
- Amira Allahham
- Burn injury research unit, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia
- Fiona Wood Foundation, 11 Robin Warren Dr, Murdoch WA 6150, Australia
| | - Grant Rowe
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, 90 South Street, Murdoch, Perth 6150, Australia
| | - Andrew Stevenson
- Burn injury research unit, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia
- Fiona Wood Foundation, 11 Robin Warren Dr, Murdoch WA 6150, Australia
| | - Mark W Fear
- Burn injury research unit, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia
- Fiona Wood Foundation, 11 Robin Warren Dr, Murdoch WA 6150, Australia
| | - Ann-Maree Vallence
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, 90 South Street, Murdoch, Perth 6150, Australia
- Centre for Healthy Ageing, Health Futures Institute, Murdoch University, 90 South Street, Murdoch Perth 6150, Australia
- Burn Service of Western Australia, Fiona Stanley Hospital, MNH (B), Level 4, 102-118 Murdoch Drive, Murdoch, Perth, WA 6150, Australia
| | - Fiona M Wood
- Burn injury research unit, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia
- Fiona Wood Foundation, 11 Robin Warren Dr, Murdoch WA 6150, Australia
- School of Psychology, College of Health and Education, Murdoch University, 90 South Street, Murdoch, Perth 6150, Australia
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Benson CA, Olson KL, Patwa S, Kauer SD, King JF, Waxman SG, Tan AM. Conditional Astrocyte Rac1KO Attenuates Hyperreflexia after Spinal Cord Injury. J Neurosci 2024; 44:e1670222023. [PMID: 37963762 PMCID: PMC10851682 DOI: 10.1523/jneurosci.1670-22.2023] [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: 09/01/2022] [Revised: 08/24/2023] [Accepted: 09/19/2023] [Indexed: 11/16/2023] Open
Abstract
Spasticity is a hyperexcitability disorder that adversely impacts functional recovery and rehabilitative efforts after spinal cord injury (SCI). The loss of evoked rate-dependent depression (RDD) of the monosynaptic H-reflex is indicative of hyperreflexia, a physiological sign of spasticity. Given the intimate relationship between astrocytes and neurons, that is, the tripartite synapse, we hypothesized that astrocytes might have a significant role in post-injury hyperreflexia and plasticity of neighboring neuronal synaptic dendritic spines. Here, we investigated the effect of selective Rac1KO in astrocytes (i.e., adult male and female mice, transgenic cre-flox system) on SCI-induced spasticity. Three weeks after a mild contusion SCI, control Rac1wt animals displayed a loss of H-reflex RDD, that is, hyperreflexia. In contrast, transgenic animals with astrocytic Rac1KO demonstrated near-normal H-reflex RDD similar to pre-injury levels. Reduced hyperreflexia in astrocytic Rac1KO animals was accompanied by a loss of thin-shaped dendritic spine density on α-motor neurons in the ventral horn. In SCI-Rac1wt animals, as expected, we observed the development of dendritic spine dysgenesis on α-motor neurons associated with spasticity. As compared with WT animals, SCI animals with astrocytic Rac1KO expressed increased levels of the glial-specific glutamate transporter, glutamate transporter-1 in the ventral spinal cord, potentially enhancing glutamate clearance from the synaptic cleft and reducing hyperreflexia in astrocytic Rac1KO animals. Taken together, our findings show for the first time that Rac1 activity in astrocytes can contribute to hyperreflexia underlying spasticity following SCI. These results reveal an opportunity to target cell-specific molecular regulators of H-reflex excitability to manage spasticity after SCI.Significance Statement Spinal cord injury leads to stretch reflex hyperexcitability, which underlies the clinical symptom of spasticity. This study shows for the first time that astrocytic Rac1 contributes to the development of hyperreflexia after SCI. Specifically, astrocytic Rac1KO reduced SCI-related H-reflex hyperexcitability, decreased dendritic spine dysgenesis on α-motor neurons, and elevated the expression of the astrocytic glutamate transporter-1 (GLT-1). Overall, this study supports a distinct role for astrocytic Rac1 signaling within the spinal reflex circuit and the development of SCI-related spasticity.
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Affiliation(s)
- Curtis A Benson
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Kai-Lan Olson
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Siraj Patwa
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Sierra D Kauer
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Jared F King
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Andrew M Tan
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510,
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
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Wu Q, Cai C, Ying X, Zheng Y, Yu J, Gu X, Tu W, Lou X, Yang G, Li M, Jiang S. Electroacupuncture inhibits dendritic spine remodeling through the srGAP3-Rac1 signaling pathway in rats with SNL. Biol Res 2023; 56:26. [PMID: 37211600 DOI: 10.1186/s40659-023-00439-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 05/10/2023] [Indexed: 05/23/2023] Open
Abstract
Previous studies have shown that peripheral nerve injury can lead to abnormal dendritic spine remodeling in spinal dorsal horn neurons. Inhibition of abnormal dendritic spine remodeling can relieve neuropathic pain. Electroacupuncture (EA) has a beneficial effect on the treatment of neuropathic pain, but the specific mechanism remains unclear. Evidence has shown that slit-robo GTPase activating protein 3 (srGAP3) and Rho GTPase (Rac1) play very important roles in dendritic spine remodeling. Here, we used srGAP3 siRNA and Rac1 activator CN04 to confirm the relationship between SrGAP3 and Rac1 and their roles in improving neuropathic pain with EA. Spinal nerve ligation (SNL) was used as the experimental model, and thermal withdrawal latency (TWL), mechanical withdrawal threshold (MWT), Western blotting, immunohistochemistry and Golgi-Cox staining were used to examine changes in behavioral performance, protein expression and dendritic spines. More dendritic spines and higher expression levels of srGAP3 were found in the initial phase of neuropathic pain. During the maintenance phase, dendritic spines were more mature, which was consistent with lower expression levels of srGAP3 and higher expression levels of Rac1-GTP. EA during the maintenance phase reduced the density and maturity of dendritic spines of rats with SNL, increased the levels of srGAP3 and reduced the levels of Rac1-GTP, while srGAP3 siRNA and CN04 reversed the therapeutic effects of EA. These results suggest that dendritic spines have different manifestations in different stages of neuropathic pain and that EA may inhibit the abnormal dendritic spine remodeling by regulating the srGAP3/Rac1 signaling pathway to alleviate neuropathic pain.
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Affiliation(s)
- Qiaoyun Wu
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Chenchen Cai
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Xinwang Ying
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Yujun Zheng
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Jiaying Yu
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Xiaoxue Gu
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Wenzhan Tu
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Xinfa Lou
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
| | - Guanhu Yang
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Ming Li
- School of Basic Medical Science, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China
| | - Songhe Jiang
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 268 Xue Yuan Xi Road, Wenzhou, 325027, Zhejiang, People's Republic of China.
- Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China.
- The Wenzhou Key Laboratory for Rehabilitation Research, The Provincial Key Laboratory for Acupuncture and Rehabilitation in Zhejiang Province, Wenzhou, China.
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Xu L, Yang L, Wu Y, Wan X, Tang X, Xu Y, Chen Q, Liu Y, Liu S. Rac1/PAK1 signaling contributes to bone cancer pain by Regulation dendritic spine remodeling in rats. Mol Pain 2023; 19:17448069231161031. [PMID: 36938611 PMCID: PMC10028669 DOI: 10.1177/17448069231161031] [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] [Indexed: 03/21/2023] Open
Abstract
Bone cancer pain (BCP) is severe chronic pain caused by tumor metastasis to the bones, often resulting in significant skeletal remodeling and fractures. Currently, there is no curative treatment. Therefore, insight into the underlying mechanisms could guide the development of mechanism-based therapeutic strategies for BCP. We speculated that Rac1/PAK1 signaling plays a critical role in the development of BCP. Tumor cells implantation (TCI) into the tibial cavity resulted in bone cancer-associated mechanical allodynia. Golgi staining revealed changes in the excitatory synaptic structure of WDR (Wide-dynamic range) neurons in the spinal cord, including increased postsynaptic density (PSD) length and thickness, and width of the cleft. Behavioral and western blotting test revealed that the development and persistence of pain correlated with Rac1/PAK1 signaling activation in primary sensory neurons. Intrathecal injection of NSC23766, a Rac1 inhibitor, reduced the persistence of BCP as well as reversed the remodeling of dendrites. Therefore, we concluded that activation of the Rac1/PAK1 signaling pathway in the spinal cord plays an important role in the development of BCP through remodeling of dendritic spines. Modulation of the Rac1/PAK1 pathway may be a potential strategy for BCP treatment.
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Affiliation(s)
- Lingfei Xu
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
| | - Long Yang
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
| | - Yan Wu
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou
Medical University, Jiangsu, China
| | - Xinxin Wan
- Department of Anesthesiology, Nanjing Drum Tower
Hospital, Jiangsu, China
| | - Xihui Tang
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou
Medical University, Jiangsu, China
| | - Yuqing Xu
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou
Medical University, Jiangsu, China
| | - Qingsong Chen
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou
Medical University, Jiangsu, China
| | - Yuepeng Liu
- Institute of Xuzhou Medical
Science, Jiangsu, China
| | - Su Liu
- Jiangsu Province Key Laboratory of
Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia
Application Technology, NMPA Key Laboratory for Research and Evaluation of
Narcotic and Psychotropic Drugs, Xuzhou Medical
University, Jiangsu, China
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou
Medical University, Jiangsu, China
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Devanathan AS, Kashuba AD. Human Immunodeficiency Virus Persistence in the Spleen: Opportunities for Pharmacologic Intervention. AIDS Res Hum Retroviruses 2021; 37:725-735. [PMID: 33499746 DOI: 10.1089/aid.2020.0266] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The persistence of HIV in the spleen, despite combination antiretroviral therapy, is not well understood. Sustained immune dysregulation and delayed immune recovery, in addition to immune cell exhaustion, may contribute to persistence of infection in the spleen. Eliminating HIV from this secondary lymphoid organ will require a thorough understanding of antiretroviral (ARV) pharmacology in the spleen, which has been minimally investigated. Low ARV exposure within the spleen may hinder the achievement of a functional or sterilizing cure if cells are not protected from HIV infection. In this study, we provide an overview of the anatomy and physiology of the spleen, review the evidence of the spleen as a site for persistence of HIV, discuss the consequences of persistence of HIV in the spleen, address challenges to eradicating HIV in the spleen, and examine opportunities for future curative efforts.
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Affiliation(s)
| | - Angela D.M. Kashuba
- UNC Eshelman School of Pharmacy, Chapel Hill, North Carolina, USA
- Division of Infectious Diseases, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
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Conditional RAC1 knockout in motor neurons restores H-reflex rate-dependent depression after spinal cord injury. Sci Rep 2021; 11:7838. [PMID: 33837249 PMCID: PMC8035187 DOI: 10.1038/s41598-021-87476-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/30/2021] [Indexed: 12/27/2022] Open
Abstract
A major complication with spinal cord injury (SCI) is the development of spasticity, a clinical symptom of hyperexcitability within the spinal H-reflex pathway. We have previously demonstrated a common structural motif of dendritic spine dysgenesis associated with hyperexcitability disorders after injury or disease insults to the CNS. Here, we used an adeno-associated viral (AAV)-mediated Cre-Lox system to knockout Rac1 protein expression in motor neurons after SCI. Three weeks after AAV9-Cre delivery into the soleus/gastrocnemius of Rac1-“floxed” adult mice to retrogradely infect spinal alpha-motor neurons, we observed significant restoration of RDD and reduced H-reflex excitability in SCI animals. Additionally, viral-mediated Rac1 knockdown reduced presence of dendritic spine dysgenesis on motor neurons. In control SCI animals without Rac1 knockout, we continued to observe abnormal dendritic spine morphology associated with hyperexcitability disorder, including an increase in mature, mushroom dendritic spines, and an increase in overall spine length and spine head size. Taken together, our results demonstrate that viral-mediated disruption of Rac1 expression in ventral horn motor neurons can mitigate dendritic spine morphological correlates of neuronal hyperexcitability, and reverse hyperreflexia associated with spasticity after SCI. Finally, our findings provide evidence of a putative mechanistic relationship between motor neuron dendritic spine dysgenesis and SCI-induced spasticity.
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Devanathan AS, Cottrell ML. Pharmacology of HIV Cure: Site of Action. Clin Pharmacol Ther 2021; 109:841-855. [PMID: 33540481 DOI: 10.1002/cpt.2187] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/08/2021] [Indexed: 12/14/2022]
Abstract
Despite significant advances in HIV treatment over the past 30 years, critical barriers to an HIV cure persist. The HIV reservoir, defined at both the cellular and anatomical level, constitutes the main barrier to cure. While the mechanisms underlying the reservoir are not yet well understood, one theory to explain persistence at the anatomical level is that subtherapeutic exposure to antiretroviral therapy (ART) within certain tissue compartments permits ongoing replication. Characterizing ART pharmacology throughout the body is important in the context of these potential pharmacologic sanctuaries and for maximizing the probability of success with forthcoming cure strategies that rely on latency reversal and require ART to prevent reseeding the reservoir. In this review, we provide a comprehensive overview of ART and latency reversal agent distribution at the site of action for HIV cure (i.e., anatomical sites commonly associated with HIV persistence, such as lymphoid organs and the central nervous system). We also discuss methodologic approaches that provide insight into HIV cure pharmacology, including experimental design and advances within the computational, pharmaceutical, and analytical chemistry fields. The information discussed in this review will assist in streamlining the development of investigational cure strategies by providing a roadmap to ensure therapeutic exposure within the site of action for HIV cure.
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Affiliation(s)
- Aaron S Devanathan
- University of North Carolina Eshelman School of Pharmacy, Chapel Hill, North Carolina, USA
| | - Mackenzie L Cottrell
- University of North Carolina Eshelman School of Pharmacy, Chapel Hill, North Carolina, USA
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9
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Sculpting Dendritic Spines during Initiation and Maintenance of Neuropathic Pain. J Neurosci 2021; 40:7578-7589. [PMID: 32998955 DOI: 10.1523/jneurosci.1664-20.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/31/2020] [Accepted: 08/21/2020] [Indexed: 12/21/2022] Open
Abstract
Accumulating evidence has established a firm role for synaptic plasticity in the pathogenesis of neuropathic pain. Recent advances have highlighted the importance of dendritic spine remodeling in driving synaptic plasticity within the CNS. Identifying the molecular players underlying neuropathic pain induced structural and functional maladaptation is therefore critical to understanding its pathophysiology. This process of dynamic reorganization happens in unique phases that have diverse pathologic underpinnings in the initiation and maintenance of neuropathic pain. Recent evidence suggests that pharmacological targeting of specific proteins during distinct phases of neuropathic pain development produces enhanced antinociception. These findings outline a potential new paradigm for targeted treatment and the development of novel therapies for neuropathic pain. We present a concise review of the role of dendritic spines in neuropathic pain and outline the potential for modulation of spine dynamics by targeting two proteins, srGAP3 and Rac1, critically involved in the regulation of the actin cytoskeleton.
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Kober KM, Schumacher M, Conley YP, Topp K, Mazor M, Hammer MJ, Paul SM, Levine JD, Miaskowski C. Signaling pathways and gene co-expression modules associated with cytoskeleton and axon morphology in breast cancer survivors with chronic paclitaxel-induced peripheral neuropathy. Mol Pain 2020; 15:1744806919878088. [PMID: 31486345 PMCID: PMC6755139 DOI: 10.1177/1744806919878088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Background The major dose-limiting toxicity of paclitaxel, one of the most commonly used
drugs to treat breast cancer, is peripheral neuropathy (paclitaxel-induced
peripheral neuropathy). Paclitaxel-induced peripheral neuropathy, which
persists into survivorship, has a negative impact on patient’s mood,
functional status, and quality of life. Currently, no interventions are
available to treat paclitaxel-induced peripheral neuropathy. A critical
barrier to the development of efficacious interventions is the lack of
understanding of the mechanisms that underlie paclitaxel-induced peripheral
neuropathy. While data from preclinical studies suggest that disrupting
cytoskeleton- and axon morphology-related processes are a potential
mechanism for paclitaxel-induced peripheral neuropathy, clinical evidence is
limited. The purpose of this study in breast cancer survivors was to
evaluate whether differential gene expression and co-expression patterns in
these pathways are associated with paclitaxel-induced peripheral
neuropathy. Methods Signaling pathways and gene co-expression modules associated with
cytoskeleton and axon morphology were identified between survivors who
received paclitaxel and did (n = 25) or did not (n = 25) develop
paclitaxel-induced peripheral neuropathy. Results Pathway impact analysis identified four significantly perturbed cytoskeleton-
and axon morphology-related signaling pathways. Weighted gene co-expression
network analysis identified three co-expression modules. One module was
associated with paclitaxel-induced peripheral neuropathy group membership.
Functional analysis found that this module was associated with four
signaling pathways and two ontology annotations related to cytoskeleton and
axon morphology. Conclusions This study, which is the first to apply systems biology approaches using
circulating whole blood RNA-seq data in a sample of breast cancer survivors
with and without chronic paclitaxel-induced peripheral neuropathy, provides
molecular evidence that cytoskeleton- and axon morphology-related mechanisms
identified in preclinical models of various types of neuropathic pain
including chemotherapy-induced peripheral neuropathy are found in breast
cancer survivors and suggests pathways and a module of genes for validation
and as potential therapeutic targets.
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Affiliation(s)
- Kord M Kober
- School of Nursing, University of California, San Francisco, CA, USA
| | - Mark Schumacher
- School of Medicine, University of California, San Francisco, CA, USA
| | - Yvette P Conley
- School of Nursing, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kimberly Topp
- School of Medicine, University of California, San Francisco, CA, USA
| | - Melissa Mazor
- School of Nursing, University of California, San Francisco, CA, USA
| | - Marilynn J Hammer
- Icahn School of Medicine, Mount Sinai Medical Center, New York, NY, USA
| | - Steven M Paul
- School of Nursing, University of California, San Francisco, CA, USA
| | - Jon D Levine
- School of Medicine, University of California, San Francisco, CA, USA
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11
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Dendritic Spine Dynamics after Peripheral Nerve Injury: An Intravital Structural Study. J Neurosci 2020; 40:4297-4308. [PMID: 32371602 DOI: 10.1523/jneurosci.2858-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/10/2020] [Accepted: 02/28/2020] [Indexed: 11/21/2022] Open
Abstract
Neuropathic pain is an intractable medical condition with few or no options for effective treatment. Emerging evidence shows a strong structure-function relationship between dendritic spine dysgenesis and the presence of neuropathic pain. Postmortem tissue analyses can only imply dynamic structural changes associated with injury-induced pain. Here, we profiled the in vivo dynamics of dendritic spines over time on the same superficial dorsal horn (lamina II) neurons before and after peripheral nerve injury-induced pain. We used a two-photon, whole-animal imaging paradigm that permitted repeat imaging of the same dendritic branches of these neurons in C57/Bl6 Thy1-YFP male mice. Our study demonstrates, for the first time, the ongoing, steady-state changes in dendritic spine dynamics in the dorsal horn associated with peripheral nerve injury and pain. Ultimately, the relationship between altered dendritic spine dynamics and neuropathic pain may serve as a structure-based opportunity to investigate mechanisms of pain following injury and disease.SIGNIFICANCE STATEMENT This work is important because it demonstrates for the first time: (1) the powerful utility of intravital study of dendritic spine dynamics in the superficial dorsal horn; (2) that nerve injury-induced pain triggers changes in dendritic spine steady-state behavior in the spinal cord dorsal horn; and (3) this work opens the door to further investigations in vivo of spinal cord dendritic spine dynamics in the context of injury and disease.
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12
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Patwa S, Benson CA, Dyer L, Olson K, Bangalore L, Hill M, Waxman SG, Tan AM. Spinal cord motor neuron plasticity accompanies second-degree burn injury and chronic pain. Physiol Rep 2019; 7:e14288. [PMID: 31858746 PMCID: PMC6923170 DOI: 10.14814/phy2.14288] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Burn injuries and associated complications present a major public health challenge. Many burn patients develop clinically intractable complications, including pain and other sensory disorders. Recent evidence has shown that dendritic spine neuropathology in spinal cord sensory and motor neurons accompanies central nervous system (CNS) or peripheral nervous system (PNS) trauma and disease. However, no research has investigated similar dendritic spine neuropathologies following a cutaneous thermal burn injury. In this retrospective investigation, we analyzed dendritic spine morphology and localization in alpha-motor neurons innervating a burn-injured area of the body (hind paw). To identify a molecular regulator of these dendritic spine changes, we further profiled motor neuron dendritic spines in adult mice treated with romidepsin, a clinically approved Pak1-inhibitor, or vehicle control at two postburn time points: Day 6 immediately after treatment, or Day 10 following drug withdrawal. In control treated mice, we observed an overall increase in dendritic spine density, including structurally mature spines with mushroom-shaped morphology. Pak1-inhibitor treatment reduced injury-induced changes to similar levels observed in animals without burn injury. The effectiveness of the Pak1-inhibitor was durable, since normalized dendritic spine profiles remained as long as 4 days despite drug withdrawal. This study is the first report of evidence demonstrating that a second-degree burn injury significantly affects motor neuron structure within the spinal cord. Furthermore, our results support the opportunity to study dendritic spine dysgenesis as a novel avenue to clarify the complexities of neurological disease following traumatic injury.
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Affiliation(s)
- Siraj Patwa
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Curtis A. Benson
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Lauren Dyer
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Kai‐Lan Olson
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Lakshmi Bangalore
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Myriam Hill
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Stephen G. Waxman
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
| | - Andrew M. Tan
- Department of Neurology and Center for Neuroscience and Regeneration ResearchYale University School of MedicineNew HavenConnecticut
- Rehabilitation Research CenterVeterans Affairs Connecticut Healthcare SystemWest HavenConnecticut
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