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Casselini CM, Parson HK, Frizzi KE, Marquez A, Smith DR, Guernsey L, Nemmani R, Tayarani A, Jolivalt CG, Weaver J, Fernyhough P, Vinik AI, Calcutt NA. A muscarinic receptor antagonist reverses multiple indices of diabetic peripheral neuropathy: preclinical and clinical studies using oxybutynin. Acta Neuropathol 2024; 147:60. [PMID: 38526612 DOI: 10.1007/s00401-024-02710-4] [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: 12/15/2023] [Revised: 02/16/2024] [Accepted: 02/17/2024] [Indexed: 03/27/2024]
Abstract
Preclinical studies indicate that diverse muscarinic receptor antagonists, acting via the M1 sub-type, promote neuritogenesis from sensory neurons in vitro and prevent and/or reverse both structural and functional indices of neuropathy in rodent models of diabetes. We sought to translate this as a potential therapeutic approach against structural and functional indices of diabetic neuropathy using oxybutynin, a muscarinic antagonist approved for clinical use against overactive bladder. Studies were performed using sensory neurons maintained in vitro, rodent models of type 1 or type 2 diabetes and human subjects with type 2 diabetes and confirmed neuropathy. Oxybutynin promoted significant neurite outgrowth in sensory neuron cultures derived from adult normal rats and STZ-diabetic mice, with maximal efficacy in the 1-100 nmol/l range. This was accompanied by a significantly enhanced mitochondrial energetic profile as reflected by increased basal and maximal respiration and spare respiratory capacity. Systemic (3-10 mg/kg/day s.c.) and topical (3% gel daily) oxybutynin reversed paw heat hypoalgesia in the STZ and db/db mouse models of diabetes and reversed paw tactile allodynia in STZ-diabetic rats. Loss of nerve profiles in the skin and cornea of db/db mice was also prevented by daily topical delivery of 3% oxybutynin for 8 weeks. A randomized, double-blind, placebo-controlled interventional trial was performed in subjects with type 2 diabetes and established peripheral neuropathy. Subjects received daily topical treatment with 3% oxybutynin gel or placebo for 6 months. The a priori designated primary endpoint, significant change in intra-epidermal nerve fibre density (IENFD) in skin biopsies taken before and after 20 weeks of treatments, was met by oxybutynin but not placebo. Secondary endpoints showing significant improvement with oxybutynin treatment included scores on clinical neuropathy, pain and quality of life scales. This proof-of-concept study indicates that muscarinic antagonists suitable for long-term use may offer a novel therapeutic opportunity for treatment of diabetic neuropathy. Trial registry number: NCT03050827.
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Affiliation(s)
- Carolina M Casselini
- Department of Internal Medicine, Strelitz Diabetes Center, Endocrine and Metabolic Disorders, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Henri K Parson
- Department of Internal Medicine, Strelitz Diabetes Center, Endocrine and Metabolic Disorders, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Katie E Frizzi
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Alex Marquez
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Darrell R Smith
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, R4046 - 351 Taché Ave, Winnipeg, MB, R2H 2A6, Canada
| | - Lucie Guernsey
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Rakesh Nemmani
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Alireza Tayarani
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Corinne G Jolivalt
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Jessica Weaver
- Department of Internal Medicine, Strelitz Diabetes Center, Endocrine and Metabolic Disorders, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, R4046 - 351 Taché Ave, Winnipeg, MB, R2H 2A6, Canada
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada
| | - Aaron I Vinik
- Department of Internal Medicine, Strelitz Diabetes Center, Endocrine and Metabolic Disorders, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, La Jolla, CA, USA.
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2
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Lv Y, Yao X, Li X, Ouyang Y, Fan C, Qian Y. Cell metabolism pathways involved in the pathophysiological changes of diabetic peripheral neuropathy. Neural Regen Res 2024; 19:598-605. [PMID: 37721290 PMCID: PMC10581560 DOI: 10.4103/1673-5374.380872] [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: 01/11/2023] [Revised: 03/31/2023] [Accepted: 06/08/2023] [Indexed: 09/19/2023] Open
Abstract
Diabetic peripheral neuropathy is a common complication of diabetes mellitus. Elucidating the pathophysiological metabolic mechanism impels the generation of ideal therapies. However, existing limited treatments for diabetic peripheral neuropathy expose the urgent need for cell metabolism research. Given the lack of comprehensive understanding of energy metabolism changes and related signaling pathways in diabetic peripheral neuropathy, it is essential to explore energy changes and metabolic changes in diabetic peripheral neuropathy to develop suitable treatment methods. This review summarizes the pathophysiological mechanism of diabetic peripheral neuropathy from the perspective of cellular metabolism and the specific interventions for different metabolic pathways to develop effective treatment methods. Various metabolic mechanisms (e.g., polyol, hexosamine, protein kinase C pathway) are associated with diabetic peripheral neuropathy, and researchers are looking for more effective treatments through these pathways.
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Affiliation(s)
- Yaowei Lv
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
| | - Xiangyun Yao
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
- Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao Li
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
- College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
| | - Yuanming Ouyang
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
- Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Cunyi Fan
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
- Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yun Qian
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
- Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, China
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3
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Ciubuc-Batcu MT, Stapelberg NJC, Headrick JP, Renshaw GMC. A mitochondrial nexus in major depressive disorder: Integration with the psycho-immune-neuroendocrine network. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166920. [PMID: 37913835 DOI: 10.1016/j.bbadis.2023.166920] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 11/03/2023]
Abstract
Nervous system processes, including cognition and affective state, fundamentally rely on mitochondria. Impaired mitochondrial function is evident in major depressive disorder (MDD), reflecting cumulative detrimental influences of both extrinsic and intrinsic stressors, genetic predisposition, and mutation. Glucocorticoid 'stress' pathways converge on mitochondria; oxidative and nitrosative stresses in MDD are largely mitochondrial in origin; both initiate cascades promoting mitochondrial DNA (mtDNA) damage with disruptions to mitochondrial biogenesis and tryptophan catabolism. Mitochondrial dysfunction facilitates proinflammatory dysbiosis while directly triggering immuno-inflammatory activation via released mtDNA, mitochondrial lipids and mitochondria associated membranes (MAMs), further disrupting mitochondrial function and mitochondrial quality control, promoting the accumulation of abnormal mitochondria (confirmed in autopsy studies). Established and putative mechanisms highlight a mitochondrial nexus within the psycho-immune neuroendocrine (PINE) network implicated in MDD. Whether lowering neuronal resilience and thresholds for disease, or linking mechanistic nodes within the MDD pathogenic network, impaired mitochondrial function emerges as an important risk, a functional biomarker, providing a therapeutic target in MDD. Several treatment modalities have been demonstrated to reset mitochondrial function, which could benefit those with MDD.
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Affiliation(s)
- M T Ciubuc-Batcu
- Griffith University School of Medicine and Dentistry, Australia; Gold Coast Health, Queensland, Australia
| | - N J C Stapelberg
- Bond University Faculty of Health Sciences and Medicine, Australia; Gold Coast Health, Queensland, Australia
| | - J P Headrick
- Griffith University School of Pharmacy and Medical Science, Australia
| | - G M C Renshaw
- Hypoxia and Ischemia Research Unit, Griffith University, School of Health Sciences and Social Work, Australia.
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Xu JW, Xu X, Ling Y, Wang YC, Huang YJ, Yang JZ, Wang JY, Shen X. Vincamine as an agonist of G-protein-coupled receptor 40 effectively ameliorates diabetic peripheral neuropathy in mice. Acta Pharmacol Sin 2023; 44:2388-2403. [PMID: 37580494 PMCID: PMC10692181 DOI: 10.1038/s41401-023-01135-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 07/09/2023] [Indexed: 08/16/2023] Open
Abstract
Diabetic peripheral neuropathy (DPN) is a common complication of diabetes, which has yet no curable medication. Neuroinflammation and mitochondrial dysfunction are tightly linked to DPN pathology. G-protein-coupled receptor 40 (GPR40) is predominantly expressed in pancreatic β-cells, but also in spinal dorsal horn and dorsal root ganglion (DRG) neurons, regulating neuropathic pain. We previously have reported that vincamine (Vin), a monoterpenoid indole alkaloid extracted from Madagascar periwinkle, is a GPR40 agonist. In this study, we evaluated the therapeutic potential of Vin in ameliorating the DPN-like pathology in diabetic mice. Both STZ-induced type 1 (T1DM) and db/db type 2 diabetic (T2DM) mice were used to establish late-stage DPN model (DPN mice), which were administered Vin (30 mg·kg-1·d-1, i.p.) for 4 weeks. We showed that Vin administration did not lower blood glucose levels, but significantly ameliorated neurological dysfunctions in DPN mice. Vin administration improved the blood flow velocities and blood perfusion areas of foot pads and sciatic nerve tissues in DPN mice. We demonstrated that Vin administration protected against sciatic nerve myelin sheath injury and ameliorated foot skin intraepidermal nerve fiber (IENF) density impairment in DPN mice. Moreover, Vin suppressed NLRP3 inflammasome activation through either β-Arrestin2 or β-Arrestin2/IκBα/NF-κB signaling, improved mitochondrial dysfunction through CaMKKβ/AMPK/SIRT1/PGC-1α signaling and alleviated oxidative stress through Nrf2 signaling in the sciatic nerve tissues of DPN mice and LPS/ATP-treated RSC96 cells. All the above-mentioned beneficial effects of Vin were abolished by GPR40-specific knockdown in dorsal root ganglia and sciatic nerve tissues. Together, these results support that pharmacological activation of GPR40 as a promising therapeutic strategy for DPN and highlight the potential of Vin in the treatment of this disease.
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Affiliation(s)
- Jia-Wen Xu
- Jiangsu Key Laboratory of Drug Target and Drug for Degenerative Diseases, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Xu Xu
- Jiangsu Key Laboratory of Drug Target and Drug for Degenerative Diseases, Nanjing University of Chinese Medicine, Nanjing, 210023, China
- Department of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Yun Ling
- Jiangsu Key Laboratory of Drug Target and Drug for Degenerative Diseases, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Yan-Chun Wang
- Jiangsu Key Laboratory of Drug Target and Drug for Degenerative Diseases, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Yu-Jie Huang
- Jiangsu Key Laboratory of Drug Target and Drug for Degenerative Diseases, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Juan-Zhen Yang
- Jiangsu Key Laboratory of Drug Target and Drug for Degenerative Diseases, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Jia-Ying Wang
- Jiangsu Key Laboratory of Drug Target and Drug for Degenerative Diseases, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Xu Shen
- Jiangsu Key Laboratory of Drug Target and Drug for Degenerative Diseases, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
- National Key Laboratory on Technologies for Chinese Medicine Pharmaceutical Process Control and Intelligent Manufacture, Nanjing, 210023, China.
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5
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Healy D. The past, present and future of anticholinergic drugs. Ther Adv Psychopharmacol 2023; 13:20451253231176375. [PMID: 37701889 PMCID: PMC10493060 DOI: 10.1177/20451253231176375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 04/28/2023] [Indexed: 09/14/2023] Open
Abstract
In current medical practice, it is difficult to find any reports claiming that drugs that are primarily anticholinergic or those that have significant anticholinergic effects have any therapeutic benefits. These drugs fell into disrepute within the mental health field from the mid-1960s onwards, and their supposed problems extended to elsewhere in medicine after that. There is considerable evidence that this disrepute stemmed more from marketing copy rather than from hard clinical trial data. Many apparent reviews appear to repeat prior claims rather than present substantial or new evidence. This article offers a perspective rather than a systematic review as there is little evidence other than claims to review. The aim is to challenge the conventional narrative that anticholinergic effects are uniquely hazardous by pointing to the uncertain basis for claims about the harms of anticholinergic drugs, antimuscarinic drugs in particular, ending with pointers to recent research that, if realized, might underpin important possible future benefits.
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Affiliation(s)
- David Healy
- Data Based Medicine Americas Ltd., 95 Sandringham Drive, Toronto, ON, M3H 1E1 Canada
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Eftekharpour E, Fernyhough P. Oxidative Stress and Mitochondrial Dysfunction Associated with Peripheral Neuropathy in Type 1 Diabetes. Antioxid Redox Signal 2022; 37:578-596. [PMID: 34416846 DOI: 10.1089/ars.2021.0152] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Significance: This review highlights the many intracellular processes generating reactive oxygen species (ROS) in the peripheral nervous system in the context of type 1 diabetes. The major sources of superoxide and hydrogen peroxide (H2O2) are described, and scavenging systems are explained. Important roles of ROS in regulating normal redox signaling and in a disease setting, such as diabetes, contributing to oxidative stress and cellular damage are outlined. The primary focus is the role of hyperglycemia in driving elevated ROS production and oxidative stress contributing to neurodegeneration in diabetic neuropathy (within the dorsal root ganglia [DRG] and peripheral nerve). Recent Advances: Contributors to ROS production under high intracellular glucose concentration such as mitochondria and the polyol pathway are discussed. The primarily damaging impact of ROS on multiple pathways including mitochondrial function, endoplasmic reticulum (ER) stress, autophagy, and epigenetic signaling is covered. Critical Issues: There is a strong focus on mechanisms of diabetes-induced mitochondrial dysfunction and how this may drive ROS production (in particular superoxide). The mitochondrial sites of superoxide/H2O2 production via mitochondrial metabolism and aerobic respiration are reviewed. Future Directions: Areas for future development are highlighted, including the need to clarify diabetes-induced changes in autophagy and ER function in neurons and Schwann cells. In addition, more clarity is needed regarding the sources of ROS production at mitochondrial sites under high glucose concentration (and lack of insulin signaling). New areas of study should be introduced to investigate the role of ROS, nuclear lamina function, and epigenetic signaling under diabetic conditions in peripheral nerve.
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Affiliation(s)
- Eftekhar Eftekharpour
- Department of Physiology and Pathophysiology and Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
| | - Paul Fernyhough
- Department of Pharmacology & Therapeutics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada.,Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
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Antagonism of the Muscarinic Acetylcholine Type 1 Receptor Enhances Mitochondrial Membrane Potential and Expression of Respiratory Chain Components via AMPK in Human Neuroblastoma SH-SY5Y Cells and Primary Neurons. Mol Neurobiol 2022; 59:6754-6770. [PMID: 36002781 PMCID: PMC9525428 DOI: 10.1007/s12035-022-03003-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/16/2022] [Indexed: 12/05/2022]
Abstract
Impairments in mitochondrial physiology play a role in the progression of multiple neurodegenerative conditions, including peripheral neuropathy in diabetes. Blockade of muscarinic acetylcholine type 1 receptor (M1R) with specific/selective antagonists prevented mitochondrial dysfunction and reversed nerve degeneration in in vitro and in vivo models of peripheral neuropathy. Specifically, in type 1 and type 2 models of diabetes, inhibition of M1R using pirenzepine or muscarinic toxin 7 (MT7) induced AMP-activated protein kinase (AMPK) activity in dorsal root ganglia (DRG) and prevented sensory abnormalities and distal nerve fiber loss. The human neuroblastoma SH-SY5Y cell line has been extensively used as an in vitro model system to study mechanisms of neurodegeneration in DRG neurons and other neuronal sub-types. Here, we tested the hypothesis that pirenzepine or MT7 enhance AMPK activity and via this pathway augment mitochondrial function in SH-SY5Y cells. M1R expression was confirmed by utilizing a fluorescent dye, ATTO590-labeled MT7, that exhibits great specificity for this receptor. M1R antagonist treatment in SH-SY5Y culture increased AMPK phosphorylation and mitochondrial protein expression (OXPHOS). Mitochondrial membrane potential (MMP) was augmented in pirenzepine and MT7 treated cultured SH-SY5Y cells and DRG neurons. Compound C or AMPK-specific siRNA suppressed pirenzepine or MT7-induced elevation of OXPHOS expression and MMP. Moreover, muscarinic antagonists induced hyperpolarization by activating the M-current and, thus, suppressed neuronal excitability. These results reveal that negative regulation of this M1R-dependent pathway could represent a potential therapeutic target to elevate AMPK activity, enhance mitochondrial function, suppress neuropathic pain, and enhance nerve repair in peripheral neuropathy.
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Resveratrol from Dietary Supplement to a Drug Candidate: An Assessment of Potential. Pharmaceuticals (Basel) 2022; 15:ph15080957. [PMID: 36015105 PMCID: PMC9412308 DOI: 10.3390/ph15080957] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/23/2022] [Accepted: 07/26/2022] [Indexed: 12/10/2022] Open
Abstract
Resveratrol (RVT) is a well known phyto-chemical and is widely used in dietary supplements and botanical products. It shows a wide range of pharmacological/beneficial effects. Therefore, it can be a potential candidate to be developed as phyto-pharmaceutical. Multiple diseases are reported to be treated by the therapeutic effect of RVT since it has antioxidant, anti-cancer activity and anti-inflammatory activities. It also has a major role in diabetes, arthritis, cardiac disorder and platelet aggregation etc. The major requirements are establishments regarding safety, efficacy profile and physicochemical characterization. As it is already being consumed in variable maximum daily dose, there should not be a major safety concern but the dose needs to be established for different indications. Clinical trials are also being reported in different parts of the world. Physicochemical properties of the moiety are also well reported. Moreover, due to its beneficial effect on health it leads to the development of some intellectual property in the form of patents.
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Jolivalt CG, Han MM, Nguyen A, Desmond F, Alves Jesus CH, Vasconselos DC, Pedneault A, Sandlin N, Dunne-Cerami S, Frizzi KE, Calcutt NA. Using Corneal Confocal Microscopy to Identify Therapeutic Agents for Diabetic Neuropathy. J Clin Med 2022; 11:jcm11092307. [PMID: 35566433 PMCID: PMC9104226 DOI: 10.3390/jcm11092307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/19/2022] [Accepted: 04/19/2022] [Indexed: 02/04/2023] Open
Abstract
Corneal confocal microscopy (CCM) is emerging as a tool for identifying small fiber neuropathy in both peripheral neuropathies and neurodegenerative disease of the central nervous system (CNS). The value of corneal nerves as biomarkers for efficacy of clinical interventions against small fiber neuropathy and neurodegenerative disease is less clear but may be supported by preclinical studies of investigational agents. We, therefore, used diverse investigational agents to assess concordance of efficacy against corneal nerve loss and peripheral neuropathy in a mouse model of diabetes. Ocular delivery of the peptides ciliary neurotrophic factor (CNTF) or the glucagon-like peptide (GLP) analog exendin-4, both of which prevent diabetic neuropathy when given systemically, restored corneal nerve density within 2 weeks. Similarly, ocular delivery of the muscarinic receptor antagonist cyclopentolate protected corneal nerve density while concurrently reversing indices of systemic peripheral neuropathy. Conversely, systemic delivery of the muscarinic antagonist glycopyrrolate, but not gallamine, prevented multiple indices of systemic peripheral neuropathy and concurrently protected against corneal nerve loss. These data highlight the potential for use of corneal nerve quantification by confocal microscopy as a bridging assay between in vitro and whole animal assays in drug development programs for neuroprotectants and support its use as a biomarker of efficacy against peripheral neuropathy.
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Zhou T, Lee A, Lo ACY, Kwok JSWJ. Diabetic Corneal Neuropathy: Pathogenic Mechanisms and Therapeutic Strategies. Front Pharmacol 2022; 13:816062. [PMID: 35281903 PMCID: PMC8905431 DOI: 10.3389/fphar.2022.816062] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/27/2022] [Indexed: 12/27/2022] Open
Abstract
Diabetes mellitus (DM) is a major global public health problem that can cause complications such as diabetic retinopathy, diabetic neuropathy, and diabetic nephropathy. Besides the reporting of reduction in corneal nerve density and decrease in corneal sensitivity in diabetic patients, there may be a subsequent result in delayed corneal wound healing and increased corneal infections. Despite being a potential cause of blindness, these corneal nerve changes have not gained enough attention. It has been proposed that corneal nerve changes may be an indicator for diabetic neuropathy, which can provide a window for early diagnosis and treatment. In this review, the authors aimed to give an overview of the relationship between corneal nerves and diabetic neuropathy as well as the underlying pathophysiological mechanisms of corneal nerve fiber changes caused by DM for improved prediction and prevention of diabetic neuropathy. In addition, the authors summarized current and novel therapeutic methods for delayed corneal wound healing, nerve protection and regeneration in the diabetic cornea.
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Affiliation(s)
- Ting Zhou
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Allie Lee
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Amy Cheuk Yin Lo
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Jeremy Sze Wai John Kwok
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Van Baelen AC, Robin P, Kessler P, Maïga A, Gilles N, Servent D. Structural and Functional Diversity of Animal Toxins Interacting With GPCRs. Front Mol Biosci 2022; 9:811365. [PMID: 35198603 PMCID: PMC8859281 DOI: 10.3389/fmolb.2022.811365] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/05/2022] [Indexed: 12/12/2022] Open
Abstract
Peptide toxins from venoms have undergone a long evolutionary process allowing host defense or prey capture and making them highly selective and potent for their target. This has resulted in the emergence of a large panel of toxins from a wide diversity of species, with varied structures and multiple associated biological functions. In this way, animal toxins constitute an inexhaustible reservoir of druggable molecules due to their interesting pharmacological properties. One of the most interesting classes of therapeutic targets is the G-protein coupled receptors (GPCRs). GPCRs represent the largest family of membrane receptors in mammals with approximately 800 different members. They are involved in almost all biological functions and are the target of almost 30% of drugs currently on the market. Given the interest of GPCRs in the therapeutic field, the study of toxins that can interact with and modulate their activity with the purpose of drug development is of particular importance. The present review focuses on toxins targeting GPCRs, including peptide-interacting receptors or aminergic receptors, with a particular focus on structural aspects and, when relevant, on potential medical applications. The toxins described here exhibit a great diversity in size, from 10 to 80 amino acids long, in disulfide bridges, from none to five, and belong to a large panel of structural scaffolds. Particular toxin structures developed here include inhibitory cystine knot (ICK), three-finger fold, and Kunitz-type toxins. We summarize current knowledge on the structural and functional diversity of toxins interacting with GPCRs, concerning first the agonist-mimicking toxins that act as endogenous agonists targeting the corresponding receptor, and second the toxins that differ structurally from natural agonists and which display agonist, antagonist, or allosteric properties.
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Affiliation(s)
- Anne-Cécile Van Baelen
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Philippe Robin
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Pascal Kessler
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Arhamatoulaye Maïga
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
- CHU Sainte Justine, Université de Montréal, Montreal, QC, Canada
| | - Nicolas Gilles
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Denis Servent
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
- *Correspondence: Denis Servent,
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12
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Covering the Role of PGC-1α in the Nervous System. Cells 2021; 11:cells11010111. [PMID: 35011673 PMCID: PMC8750669 DOI: 10.3390/cells11010111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/21/2021] [Accepted: 12/28/2021] [Indexed: 12/16/2022] Open
Abstract
The peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is a well-known transcriptional coactivator involved in mitochondrial biogenesis. PGC-1α is implicated in the pathophysiology of many neurodegenerative disorders; therefore, a deep understanding of its functioning in the nervous system may lead to the development of new therapeutic strategies. The central nervous system (CNS)-specific isoforms of PGC-1α have been recently identified, and many functions of PGC-1α are assigned to the particular cell types of the central nervous system. In the mice CNS, deficiency of PGC-1α disturbed viability and functioning of interneurons and dopaminergic neurons, followed by alterations in inhibitory signaling and behavioral dysfunction. Furthermore, in the ALS rodent model, PGC-1α protects upper motoneurons from neurodegeneration. PGC-1α is engaged in the generation of neuromuscular junctions by lower motoneurons, protection of photoreceptors, and reduction in oxidative stress in sensory neurons. Furthermore, in the glial cells, PGC-1α is essential for the maturation and proliferation of astrocytes, myelination by oligodendrocytes, and mitophagy and autophagy of microglia. PGC-1α is also necessary for synaptogenesis in the developing brain and the generation and maintenance of synapses in postnatal life. This review provides an outlook of recent studies on the role of PGC-1α in various cells in the central nervous system.
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Diaz MM, Keltner JR, Simmons AN, Franklin D, Moore RC, Clifford D, Collier AC, Gelman BB, Marra PD,C, McCutchan JA, Morgello S, Sacktor N, Best B, Notestine CF, Weibel SG, Grant I, Marcotte TD, Vaida F, Letendre S, Heaton R, Ellis RJ. Paresthesia Predicts Increased Risk of Distal Neuropathic Pain in Older People with HIV-Associated Sensory Polyneuropathy. PAIN MEDICINE (MALDEN, MASS.) 2021; 22:1850-1856. [PMID: 33565583 PMCID: PMC8502467 DOI: 10.1093/pm/pnab056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Distal sensory polyneuropathy (DSP) is a disabling consequence of human immunodeficiency virus (HIV), leading to poor quality of life and more frequent falls in older age. Neuropathic pain and paresthesia are prevalent symptoms; however, there are currently no known curative treatments and the longitudinal course of pain in HIV-associated DSP is poorly characterized. METHODS This was a prospective longitudinal study of 265 people with HIV (PWH) enrolled in the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) study with baseline and 12-year follow-up evaluations. Since pain and paresthesia are highly correlated, statistical decomposition was used to separate the two symptoms at baseline. Multivariable logistic regression analyses of decomposed variables were used to determine the effects of neuropathy symptoms at baseline on presence and worsening of distal neuropathic pain at 12-year follow-up, adjusted for covariates. RESULTS Mean age was 56 ± 8 years, and 21% were female at follow-up. Nearly the entire cohort (96%) was on antiretroviral therapy (ART), and 82% had suppressed (≤50 copies/mL) plasma viral loads at follow-up. Of those with pain at follow-up (n = 100), 23% had paresthesia at the initial visit. Decomposed paresthesia at baseline increased the risk of pain at follow-up (odds ratio [OR] 1.56; 95% confidence interval [CI] 1.18, 2.07), and decomposed pain at baseline predicted a higher frequency of pain at follow-up (OR 1.96 [95% CI 1.51, 2.58]). CONCLUSIONS Paresthesias are a clinically significant predictor of incident pain at follow-up among aging PWH with DSP. Development of new therapies to encourage neuroregeneration might take advantage of this finding to choose individuals likely to benefit from treatment preventing incident pain.
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Affiliation(s)
- Monica M Diaz
- Department of Neurosciences, University of California, San Diego, La Jolla, California
| | - John R Keltner
- Center of Excellence in Stress and Mental Health, San Diego Veterans Health System, San Diego, California
- Department of Psychiatry, University of California, San Diego, La Jolla, California
| | - Alan N Simmons
- Center of Excellence in Stress and Mental Health, San Diego Veterans Health System, San Diego, California
- Department of Psychiatry, University of California, San Diego, La Jolla, California
| | - Donald Franklin
- Department of Psychiatry, University of California, San Diego, La Jolla, California
| | - Raeanne C Moore
- Department of Psychiatry, University of California, San Diego, La Jolla, California
| | | | | | | | | | - J Allen McCutchan
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Susan Morgello
- Icahn School of Medicine at Mount Sinai, New York, New York
| | - Ned Sacktor
- Johns Hopkins University, Baltimore, Maryland
| | - Brookie Best
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California
| | | | - Sara Gianella Weibel
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Igor Grant
- Department of Psychiatry, University of California, San Diego, La Jolla, California
| | - Thomas D Marcotte
- Department of Psychiatry, University of California, San Diego, La Jolla, California
| | - Florin Vaida
- Department of Family Medicine and Public Health, University of California, San Diego, La Jolla, California, USA
| | - Scott Letendre
- Department of Psychiatry, University of California, San Diego, La Jolla, California
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Robert Heaton
- Department of Psychiatry, University of California, San Diego, La Jolla, California
| | - Ronald J Ellis
- Department of Neurosciences, University of California, San Diego, La Jolla, California
- Department of Psychiatry, University of California, San Diego, La Jolla, California
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Han MM, Frizzi KE, Ellis RJ, Calcutt NA, Fields JA. Prevention of HIV-1 TAT Protein-Induced Peripheral Neuropathy and Mitochondrial Disruption by the Antimuscarinic Pirenzepine. Front Neurol 2021; 12:663373. [PMID: 34211430 PMCID: PMC8239242 DOI: 10.3389/fneur.2021.663373] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/21/2021] [Indexed: 12/25/2022] Open
Abstract
HIV-associated distal sensory polyneuropathy (HIV-DSP) affects about one third of people with HIV and is characterized by distal degeneration of axons. The pathogenesis of HIV-DSP is not known and there is currently no FDA-approved treatment. HIV trans-activator of transcription (TAT) is associated with mitochondrial dysfunction and neurotoxicity in the brain and may play a role in the pathogenesis of HIV-DSP. In the present study, we measured indices of peripheral neuropathy in the doxycycline (DOX)-inducible HIV-TAT (iTAT) transgenic mouse and investigated the therapeutic efficacy of a selective muscarinic subtype-1 receptor (M1R) antagonist, pirenzepine (PZ). PZ was selected as we have previously shown that it prevents and/or reverses indices of peripheral neuropathy in multiple disease models. DOX alone induced weight loss, tactile allodynia and paw thermal hypoalgesia in normal C57Bl/6J mice. Conduction velocity of large motor fibers, density of small sensory nerve fibers in the cornea and expression of mitochondria-associated proteins in sciatic nerve were unaffected by DOX in normal mice, whereas these parameters were disrupted when DOX was given to iTAT mice to induce TAT expression. Daily injection of PZ (10 mg/kg s.c.) prevented all of the disorders associated with TAT expression. These studies demonstrate that TAT expression disrupts mitochondria and induces indices of sensory and motor peripheral neuropathy and that M1R antagonism may be a viable treatment for HIV-DSP. However, some indices of neuropathy in the DOX-inducible TAT transgenic mouse model can be ascribed to DOX treatment rather than TAT expression and data obtained from animal models in which gene expression is modified by DOX should be accompanied by appropriate controls and treated with due caution.
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Affiliation(s)
- May Madi Han
- Department of Pathology, University of California, San Diego, La Jolla, CA, United States
| | - Katie E Frizzi
- Department of Pathology, University of California, San Diego, La Jolla, CA, United States
| | - Ronald J Ellis
- Department of Neuroscience, University of California, San Diego, La Jolla, CA, United States.,Department of Psychiatry, University of California, San Diego, La Jolla, CA, United States
| | - Nigel A Calcutt
- Department of Pathology, University of California, San Diego, La Jolla, CA, United States
| | - Jerel Adam Fields
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, United States
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Li Y, Lustberg MB, Hu S. Emerging Pharmacological and Non-Pharmacological Therapeutics for Prevention and Treatment of Chemotherapy-Induced Peripheral Neuropathy. Cancers (Basel) 2021; 13:cancers13040766. [PMID: 33673136 PMCID: PMC7918689 DOI: 10.3390/cancers13040766] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/04/2021] [Accepted: 02/08/2021] [Indexed: 12/25/2022] Open
Abstract
Simple Summary Chemotherapy-induced peripheral neuropathy (CIPN) is a common and persistent complication of commonly used chemotherapy drugs. This article provides an overview of emerging therapeutics for the prevention and treatment of CIPN and focuses on pharmacological strategies that are derived from novel mechanistic insights and have the potential to be translated into clinically beneficial approaches. It is our contention to call for fostering collaboration between basic and clinical researchers to improve the development of effective strategies. Abstract Chemotherapy-induced peripheral neuropathy (CIPN) is a common adverse event of several first-line chemotherapeutic agents, including platinum compounds, taxanes, vinca alkaloids, thalidomide, and bortezomib, which negatively affects the quality of life and clinical outcome. Given the dearth of effective established agents for preventing or treating CIPN, and the increasing number of cancer survivors, there is an urgent need for the identification and development of new, effective intervention strategies that can prevent or mitigate this debilitating side effect. Prior failures in the development of effective interventions have been due, at least in part, to a lack of mechanistic understanding of CIPN and problems in translating this mechanistic understanding into testable hypotheses in rationally-designed clinical trials. Recent progress has been made, however, in the pathogenesis of CIPN and has provided new targets and pathways for the development of emerging therapeutics that can be explored clinically to improve the management of this debilitating toxicity. This review focuses on the emerging therapeutics for the prevention and treatment of CIPN, including pharmacological and non-pharmacological strategies, and calls for fostering collaboration between basic and clinical researchers to improve the development of effective strategies.
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Affiliation(s)
- Yang Li
- Division of Pharmaceutics and Pharmacology, College of Pharmacy & Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA;
| | - Maryam B. Lustberg
- Comprehensive Cancer Center, Department of Medical Oncology, The Ohio State University, Columbus, OH 43210, USA;
| | - Shuiying Hu
- Division of Pharmaceutics and Pharmacology, College of Pharmacy & Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA;
- Correspondence: ; Tel.: +1-614-685-8028
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