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Zimering MB. A Serotonin 2A-Receptor Decoy Peptide Potently Lowers Blood Pressure in Male Zucker Diabetic, Fatty, Hypertensive Rats. ENDOCRINOLOGY, DIABETES AND METABOLISM JOURNAL 2021; 5:10.31038/edmj.2021523. [PMID: 35035793 PMCID: PMC8759716 DOI: 10.31038/edmj.2021523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
AIMS To test whether a novel 5-hydroxytryptamine 2A decoy receptor peptide, SN..8 (Sertuercept), administered via intraperitoneal injection, acutely lowers arterial blood pressure in obese, hypertensive male Zucker diabetic rats (ZDF). To examine the safety, tolerability and possible reno-protective effects following chronic alternate daily administration of Sertuercept (for 10 weeks) in the male ZDF rat. METHODS Systolic and diastolic blood pressure were determined at baseline and regular intervals for up to 48 hours after a single IP administration of either Sertuercept (2 mg/kg), vehicle (saline) or an identical concentration of a scrambled sequence of the decoy receptor peptide, LN…8, in male ZDF and Zucker lean rats using tail cuff plethysmography. Plasma autoantibodies were obtained in thirteen male ZDF rats for determination of 5-hydroxytryptamine 2A receptor-mediated neurotoxicity using an acute neurite retraction assay in mouse neuroblastoma cells. Rats were sacrificed at 25-weeks of age, the kidneys were perfused, fixed and sections were stained using Masson's trichrome for semi-quantitative determination of glomerular and interstitial fibrosis. RESULTS Sertuercept (2 mg/kg IP) potently lowered systolic and diastolic blood pressure in both 11-week-old and 25-week-old male ZDF rats and in a subset of hypertensive Zucker lean rats. There was no significant blood pressure-lowering effect of vehicle (saline) or scrambled peptide sequence (LN.8). Blood pressure-lowering was rapid in onset (15-30 minutes following IP injection) and sustained for at least 24 hours. Alternate daily IP administration of 2 mg/kg dose of Sertuercept vs. scrambled peptide (for 10 weeks) was safe, well-tolerated and associated with a significant decrease in glomerulosclerosis in 25-week-old male ZDF rats. Plasma autoantibody-induced neurotoxicity correlated significantly with the global index of renal fibrosis severity in 25-week-old male ZDF rats. CONCLUSIONS These data indicate potent arterial blood pressure-lowering efficacy from a decoy receptor peptide comprised of a second extracellular loop region of the human 5-hydroxytryptamine receptor. Chronic administration of the decoy receptor peptide (10 weeks) was safe, well-tolerated and protected against renal glomerulosclerosis in the male ZDF rat.
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Affiliation(s)
- Mark B. Zimering
- Endocrine Section, Veterans Affair New Jersey Healthcare System, East Orange, New Jersey, USA
- Endocrinology, Rutgers-Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
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Zimering MB, Delic V, Citron BA. Gene Expression Changes in a Model Neuron Cell Line Exposed to Autoantibodies from Patients with Traumatic Brain Injury and/or Type 2 Diabetes. Mol Neurobiol 2021; 58:4365-4375. [PMID: 34013450 PMCID: PMC8487420 DOI: 10.1007/s12035-021-02428-4] [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: 03/16/2021] [Accepted: 05/11/2021] [Indexed: 11/24/2022]
Abstract
Traumatic brain injury and adult type 2 diabetes mellitus are each associated with the late occurrence of accelerated cognitive decline and Parkinson’s disease through unknown mechanisms. Previously, we reported increased circulating agonist autoantibodies targeting the 5-hydroxytryptamine 2A receptor in plasma from subsets of Parkinson’s disease, dementia, and diabetic patients suffering with microvascular complications. Here, we use a model neuron, mouse neuroblastoma (N2A) cell line, to test messenger RNA expression changes following brief exposure to traumatic brain injury and/or type 2 diabetes mellitus plasma harboring agonist 5-hydroxytryptamine 2A receptor autoantibodies. We now report involvement of the mitochondrial dysfunction pathway and Parkinson’s disease pathways in autoantibody-induced gene expression changes occurring in neuroblastoma cells. Functional gene categories upregulated significantly included cell death, cytoskeleton-microtubule function, actin polymerization or depolymerization, regulation of cell oxidative stress, mitochondrial function, immune function, protein metabolism, and vesicle function. Gene categories significantly downregulated included microtubule function, cell adhesion, neurotransmitter release, dopamine metabolism synaptic plasticity, maintenance of neuronal differentiation, mitochondrial function, and cell signaling. Taken together, these results suggest that agonist 5-hydroxytryptamine receptor autoantibodies (which increase in Parkinson’s disease and other forms of neurodegeneration) mediate a coordinating program of gene expression changes in a model neuron which predispose to neuro-apoptosis and are linked to human neurodegenerative diseases pathways.
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Affiliation(s)
- Mark B Zimering
- Endocrine and Diabetes Section, Medical Service, VA New Jersey Healthcare System, 385 Tremont Ave, East Orange, NJ, 07018, USA. .,Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
| | - Vedad Delic
- Laboratory of Molecular Biology, VA New Jersey Health Care System, Research & Development (Mailstop 15), 385 Tremont Ave, East Orange, NJ, 07018, USA
| | - Bruce A Citron
- Laboratory of Molecular Biology, VA New Jersey Health Care System, Research & Development (Mailstop 15), 385 Tremont Ave, East Orange, NJ, 07018, USA.,Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ, USA
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Zimering MB. Severe COVID-19 Pneumonia is Associated with Increased Plasma Immunoglobulin G Agonist Autoantibodies Targeting the 5-Hydroxytryptamine 2A Receptor. ENDOCRINOLOGY, DIABETES AND METABOLISM JOURNAL 2021; 5:1-9. [PMID: 33680365 DOI: 10.31038/edmj.2021511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aims To test whether plasma autoantibodies targeting the 5-hydroxytryptamine 2A receptor increase in COVID-19 infection; and to characterize the pharmacologic specificity, and signaling pathway activation occurring downstream of receptor binding in mouse neuroblastoma N2A cells and cell toxicity of the autoantibodies. Methods Plasma obtained from nineteen, older COVID-19 patients having mild or severe infection was subjected to protein-A affinity chromatography to obtain immunoglobulin G fraction. One-fortieth dilution of the protein-A eluate was tested for binding to a linear synthetic peptide QN.18 corresponding to the second extracellular loop of the human 5-hydroxytryptamine 2A receptor. Mouse neuroblastoma N2A cells were incubated with COVID-19 IgG autoantibodies in the presence or absence of selective inhibitors of G-protein coupled receptors, signaling pathway antagonists, or a novel decoy receptor peptide. Results 5-hydroxytryptamine 2A receptor autoantibody binding occurred in 17 of 19 (89%) patients with acute COVID-19 infection and increased level was significantly correlated with increased severity of COVID-19 infection. The agonist autoantibodies mediated acute neurite retraction in mouse neuroblastoma cells by a mechanism involving Gq11/PLC/IP3R/Ca2+ activation and RhoA/Rho kinase pathway signaling occurring downstream of receptor binding which had pharmacologic specificity consistent with binding to the 5-HT2A receptor. A novel synthetic peptide 5-HT2AR fragment, SN..8, dose-dependently blocked autoantibody-induced neurotoxicity. The COVID-19 autoantibodies displayed acute toxicity in bovine pulmonary artery endothelial cells (stress fiber formation, contraction) and modulated proliferation in a manner consistent with known 'biased agonism' on the 5-HT2A receptor. Conclusion These data suggest that 5-HT2AR targeting autoantibodies are highly prevalent may contribute to pathophysiology in acute, severe COVID-19 infection.
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Affiliation(s)
- Mark B Zimering
- Veterans Affairs New Jersey Healthcare System, East Orange NJ, USA.,Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA
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Skiba MA, Kruse AC. Autoantibodies as Endogenous Modulators of GPCR Signaling. Trends Pharmacol Sci 2020; 42:135-150. [PMID: 33358695 DOI: 10.1016/j.tips.2020.11.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 11/24/2020] [Accepted: 11/28/2020] [Indexed: 02/06/2023]
Abstract
Endogenous self-reactive autoantibodies (AAs) recognize a range of G-protein-coupled receptors (GPCRs). They are frequently associated with cardiovascular, neurological, and autoimmune disorders, and in some cases directly impact disease progression. Many GPCR AAs modulate receptor signaling, but molecular details of their modulatory activity are not well understood. Technological advances have provided insight into GPCR biology, which now facilitates deeper understanding of GPCR AA function at the molecular level. Most GPCR AAs are allosteric modulators and exhibit a broad range of pharmacological properties, altering both receptor signaling and trafficking. Understanding GPCR AAs is not only important for defining how these unusual GPCR modulators function in disease, but also provides insight into the potential use and limitations of using therapeutic antibodies to modulate GPCR signaling.
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Affiliation(s)
- Meredith A Skiba
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Andrew C Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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Zhao Q, Zhang Y, Liao X, Wang W. Executive Function and Diabetes: A Clinical Neuropsychology Perspective. Front Psychol 2020; 11:2112. [PMID: 32973635 PMCID: PMC7468478 DOI: 10.3389/fpsyg.2020.02112] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/29/2020] [Indexed: 02/05/2023] Open
Abstract
Objective Diabetes is a global public health concern. Management of diabetes depends on successful implementation of strategies to alleviate decline in executive functions (EFs), a characteristic of diabetes progression. In this review, we describe recent research on the relationship between diabetes and EF, summarize the existing evidence, and put forward future research directions and applications. Methods Herein, we provide an overview of recent studies, to elucidate the relationship between DM and EF. We identified new screening objectives, management tools, and intervention targets for diabetes management. We also discuss the implications for clinical practice. Results In both types 1 and 2 diabetes mellitus (DM), hyperglycemia substantially impairs EF in people of all age groups and ethnicities. Hypoglycemia can similarly impair EF. Interestingly, a decline in EF contributes to DM progression. Glucose dysregulation and EF decline exacerbate each other in a vicious cycle: poor blood glucose control, impaired EF, diabetes management task failure, then back to poor blood glucose control. Many pathophysiological indexes (e.g., obesity, metabolic index, inflammatory and immune factors), neuropsychological indexes (e.g., compliance, eating habits, physical exercise, sleep, and depression), and genetic factors are changed by this pathological interaction between DM and EF. These changes can provide insight into the pathophysiological mechanisms of diabetes-related EF decline. Conclusion Further studies, including large-scale prospective and randomized controlled trials, are needed to elucidate the mechanism of the interaction between diabetes and EF and to develop novel strategies for breaking this cycle.
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Affiliation(s)
- Qian Zhao
- International Medical Center/Ward of General Practice and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yonggang Zhang
- Department of Periodical Press and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoyang Liao
- International Medical Center/Ward of General Practice and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Weiwen Wang
- Department of Neurology, General Hospital of Western Theater Command, Chengdu, China
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Zimering MB, Grinberg M, Burton J, Pang KCH. Circulating Agonist Autoantibody to 5-Hydroxytryptamine 2A Receptor in Lean and Diabetic Fatty Zucker Rat Strains. ENDOCRINOLOGY, DIABETES AND METABOLISM JOURNAL 2020; 4:413. [PMID: 33052255 PMCID: PMC7550200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
AIMS Circulating neurotoxic autoantibodies to the 5-hydroxytryptamine 2A receptor were increased in older adult type 2 diabetes in association with certain neurodegenerative complications. The male Zucker diabetic fatty (ZDF) rat is a model system for studies of obese, type 2 diabetes mellitus. The aim of the current study was to test for (and compare) circulating neurotoxic autoantibodies to the 5-hydroxytryptamine 2A receptor in the Zucker diabetic fatty rat and age-matched lean Zucker rat strains. METHODS Plasma from lean and Zucker diabetic fatty rat (obtained at different developmental stages) was subjected to protein G affinity chromatography. The resulting immunoglobulin G fraction was tested for neurotoxicity (acute neurite retraction, accelerated neuron loss) in N2A mouse neuroblastoma cells and for binding to a linear synthetic peptide corresponding to the second extracellular loop of the 5-hydroxytryptamine 2A receptor. RESULTS The male Zucker diabetic fatty rat (fa/fa) and two Zucker lean strains (+/?) and (fa/+) harbored autoantibodies to the 5-hydroxytryptamine 2A receptor which appeared spontaneously around 7-8.5 weeks of age. The circulating autoantibodies persisted until at least 25 weeks of age in the Zucker diabetic fatty rat and in the Zucker heterozygote (fa/+), but were no longer detectable in 25-week-old lean (+/?) Zucker rats. Autoantibody-induced acute neurite retraction and accelerated loss in mouse neuroblastoma N2A cells was dose-dependently prevented by selective antagonists of the 5-hydroxytryptamine 2A receptor. It was also substantially prevented by co-incubation with antagonists of RhoA/Rho kinase-mediated signaling (Y27632) or Gq11/phospholipase C/inositol triphosphate receptor-coupled signaling. CONCLUSIONS These data suggest that neurotoxic 5-hydroxytryptamine 2A receptor-targeting autoantibodies increase in the aging male Zucker diabetic fatty rat and in male Zucker lean rats harboring a heterozygous mutation, but not in age-matched, older Zucker lean rats lacking a known leptin receptor mutation. The Zucker genetic strain may be useful in studies of the role of humoral and/or innate immunity in late neurodegeneration.
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Affiliation(s)
- MB Zimering
- Medical Service, Veterans Affairs New Jersey Healthcare
System, East Orange, New Jersey, USA
- Rutgers-Robert Wood Johnson Medical School, New Brunswick,
NJ
| | - M Grinberg
- Medical Service, Veterans Affairs New Jersey Healthcare
System, East Orange, New Jersey, USA
| | - J Burton
- Medical Service, Veterans Affairs New Jersey Healthcare
System, East Orange, New Jersey, USA
| | - KCH Pang
- Medical Service, Veterans Affairs New Jersey Healthcare
System, East Orange, New Jersey, USA
- Rutgers-New Jersey Medical School, Newark, New Jersey,
USA
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Luo Y, Liu X, Ma R, Wang Y, Zimering M, Pan Z. Circulating IgGs in Type 2 Diabetes with Atrial Fibrillation Induce IP 3-Mediated Calcium Elevation in Cardiomyocytes. iScience 2020; 23:101036. [PMID: 32315831 PMCID: PMC7170991 DOI: 10.1016/j.isci.2020.101036] [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: 08/30/2019] [Revised: 01/16/2020] [Accepted: 04/01/2020] [Indexed: 11/06/2022] Open
Abstract
Higher risk of cardiac arrhythmias including atrial fibrillation (AF) associates with type 2 diabetes mellitus (T2DM) with the underlying mechanism largely unknown. The present study reported a subset of circulating immunoglobulin G autoantibodies (IgGs) from patients with T2DM with AF (T2DM/AF)-induced intracellular calcium elevation in both human induced pluripotent stem cell (iPSC)-derived and mouse atrial cardiomyocytes, whereas (identical concentrations of) IgGs from patients with T2DM without AF could not. The IgG-evoked intracellular calcium elevation was insensitive to verapamil, mibefradil, or BTP-2, indicating calcium source from neither voltage-gated calcium channels nor store-operated calcium entry. On the other hand, pharmacological antagonism or genetic knockdown of inositol triphosphate (IP3) receptor significantly decreased T2DM/AF IgG-induced intracellular calcium elevation. Furthermore, pharmacological blockage of G protein-coupled receptor (GPCR), heterotrimeric G protein or phospholipase C dampened IgG-induced intracellular calcium elevation. Taken together, circulating IgGs from patients with T2DM/AF stimulated arrhythmogenic intracellular calcium elevation through IP3 pathway in atrial cardiomyocytes. Identification of cardiomyocyte-targeting IgGs in T2DM atrial fibrillation patients Induction of arrhythmogenic Ca2+ signaling by these IgGs Independent of voltage-gated or store-operated Ca2+ channels Involvement of GPCR-IP3-IP3R axis in IgG-evoked intracellular Ca2+ elevation
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Affiliation(s)
- Yanhong Luo
- Davis Heart and Lung Research Institute, Ohio State University-Wexner Medical Center, Columbus, OH 43210, USA; Department of Endocrinology, The Children's Hospital of Chongqing Medical University, Chongqing, P. R. China
| | - Xian Liu
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX 76010, USA; College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, TX 76010, USA
| | - Ruilian Ma
- Division of Regenerative Medicine Research, Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45219, USA
| | - Yigang Wang
- Division of Regenerative Medicine Research, Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45219, USA
| | - Mark Zimering
- Endocrinology, Veterans Affairs New Jersey Healthcare System, East Orange, NJ 07018, USA; Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA.
| | - Zui Pan
- Davis Heart and Lung Research Institute, Ohio State University-Wexner Medical Center, Columbus, OH 43210, USA; Department of Kinesiology, University of Texas at Arlington, Arlington, TX 76010, USA; College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, TX 76010, USA.
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Zimering MB, Pulikeyil AT, Myers CE, Pang KC. Serotonin 2A Receptor Autoantibodies Increase in Adult Traumatic Brain Injury In Association with Neurodegeneration. JOURNAL OF ENDOCRINOLOGY AND DIABETES 2020; 7:1-8. [PMID: 32671201 PMCID: PMC7362960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
OBJECTIVE Traumatic brain injury (TBI) is associated with an increased risk of late neurodegenerative complications via unknown mechanisms. Circulating neurotoxic 5-hydroxytryptamine 2A receptor (5-HT2AR) autoantibodies were reported to increase in subsets of obese type 2 diabetes having microvascular complications. We tested whether 5-HT2AR autoantibodies increase in adults following traumatic brain injury in association with neurodegenerative complications. METHODS Plasma from thirty-five middle-aged and older adult veterans (mean 65 years old) who had suffered traumatic brain injury was subjected to protein-A affinity chromatography. The resulting immunoglobulin (Ig) G fraction was tested for neurotoxicity (acute neurite retraction, and accelerated cell death) in mouse N2A neuroblastoma cells or for binding to a linear synthetic peptide corresponding to the second extracellular loop region of the human 5-HT2A receptor. RESULTS Nearly two-thirds of traumatic brain injured-patients harbored 5-HT2AR autoantibodies in their circulation. Active TBI autoantibodies caused neurite retraction in mouse N2A neuroblastoma cells and accelerated N2A cell loss which was substantially prevented by co-incubation with a two hundred and fifty nanomolar concentration of M100907, a highly selective 5-HT2AR antagonist. Antagonists of RhoA/Rho kinase and Gq11/phospholipase C/inositol triphosphate receptor signaling pathways blocked TBI autoantibody-induced neurite retraction. Following traumatic brain injury, autoantibody binding to a 5-HT2A receptor peptide was significantly increased in patients having co-morbid Parkinson's disease (n=3), dementia (n=5), and painful neuropathy (n=8) compared to TBI subsets without neurologic or microvascular complication (n=20). Autoantibody titer was significantly elevated in TBI subsets experiencing multiple neurotraumatic exposures vs. single TBI. Plasma white blood cell, a marker of systemic inflammation, correlated significantly (correlation coefficient r =0.52; P < 0.01) with, 5-HT2A receptor peptide binding of the TBI-autoantibody. CONCLUSION These data suggest that circulating neurotoxic 5-hydroxytryptamine 2A receptor agonist autoantibodies increase in adults following traumatic brain injury in association with late neurodegenerative complications.
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Affiliation(s)
- Mark B. Zimering
- Veterans Affairs New Jersey Healthcare System, East Orange, NJ
- Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ
| | | | - Catherine E. Myers
- Veterans Affairs New Jersey Healthcare System, East Orange, NJ
- Rutgers-New Jersey Medical School, Newark, NJ
| | - Kevin C. Pang
- Veterans Affairs New Jersey Healthcare System, East Orange, NJ
- Rutgers-New Jersey Medical School, Newark, NJ
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Zimering MB, Nadkarni SG. Schizophrenia Plasma Autoantibodies Promote 'Biased Agonism' at the 5-Hydroxytryptamine 2A Receptor: Neurotoxicity is Positively Modulated by Metabotropic Glutamate 2/3 Receptor Agonism. ENDOCRINOLOGY, DIABETES AND METABOLISM JOURNAL 2019; 3:http://researchopenworld.com/wp-content/uploads/2019/08/EDMJ-2019-117-Mark-Zimering-USA.pdf. [PMID: 31537990 PMCID: PMC6751558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
AIMS To test whether neurite-inhibitory plasma autoantibodies in chronic schizophrenia activate Gq/11- and Gi- coupled signaling pathways downstream of 5-hydroxytryptamine 2A receptor activation; and for modulation of serotonergic signaling by the metabotropic 2/3 receptor agonist LY379268. METHODS Plasma from five older adults with chronic schizophrenia and eight age-matched patients having another neuropsychiatric, immune or metabolic disorder was subjected to Protein-A affinity chromatography to obtain IgG autoantibodies. Mean neurite retraction (5 minutes) or cell survival (24 hours) was determined in mouse N2A neuroblastoma cells incubated with autoantibodies in the presence or absence of specific antagonists of the Gq/11/PLC/IP3R signaling pathway, Gi-coupled, beta-arrestin2-directed pathways, or LY379268. RESULTS Chronic schizophrenia plasma autoantibodies- mediated dose- and time-dependent acute N2A neurite retraction was completely prevented by M100907, a selective 5-hydroxytryptamine 2A receptor antagonist. LY379268 promoted autoantibody-induced neurite retraction causing a shift-to-the-left in the dose-response curve. Antagonists of the RhoA/Rho kinase and Gq/11/PLC/IP3R signaling pathways blocked autoantibody-mediated neurite retraction. Chronic schizophrenia plasma autoantibodies mediated increased N2A cell survival which was blocked by LY379268, pertussis toxin, and antagonists of PI3-kinase- mediated survival signaling. CONCLUSION Schizophrenia plasma autoantibodies activate the 5-hydroxytryptamine 2A receptor positively coupled to Gq/11/PLC/IP3R pathway and RhoA/Rho kinase signaling activation in promoting acute N2A cell neurite retraction. Autoantibodies in a subset of patients experiencing hallucinations promoted increased N2A cell survival mediated (in part) via a pertussis-toxin sensitive, Gi-coupled, PI3-kinase-dependent mechanism. Positive modulation of 5-HT2AR-mediated neurite retraction by LY379268 suggests the autoantibodies may target (in part) the 5-HT2AR/mGlu2R heteromer.
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Affiliation(s)
- Mark B. Zimering
- Veterans Affairs New Jersey Healthcare System, East Orange, NJ, USA
- Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA
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Zimering MB. Autoantibodies in Type-2 Diabetes having Neurovascular Complications Bind to the Second Extracellular Loop of the 5-Hydroxytryptamine 2A Receptor. ENDOCRINOLOGY, DIABETES AND METABOLISM JOURNAL 2019; 3:118. [PMID: 31565198 PMCID: PMC6764514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Mark B. Zimering
- Endocrinology, Veterans Affairs New Jersey Healthcare System, East Orange, NJ and Rutgers-Robert Wood Johnson Medical School, New Brunswick NJ, USA
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Zimering MB, Patel D, Bahn G. Type 2 Diabetes Predicts Increased Risk of Neurodegenerative Complications in Veterans Suffering Traumatic Brain Injury. JOURNAL OF ENDOCRINOLOGY AND DIABETES 2019; 6:137. [PMID: 31828222 PMCID: PMC6905496 DOI: 10.15226/2374-6890/6/3/001137] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AIMS Obese type 2 diabetes and traumatic brain injury are associated with persistent peripheral and neuro-inflammation, respectively. We tested whether adult type 2 diabetes increased the hazard rate for neurodegeneration complications following traumatic brain injury. METHODS Retrospective chart review of patients treated at the Veterans Affairs New Jersey Healthcare System between 2016-2019 and having a diagnosis of prior traumatic brain injury was performed in adult veterans, age 50 years or older. Cox proportional hazards regression analysis was used to identify risk factors predictive of an increased risk of neurodegeneration, i.e. worsening major depression, dementia or Parkinson's disease following traumatic brain injury. RESULTS Type 2 diabetes predicted a nearly three-fold increased hazard ratio (HR = 2.95, 95% CI 1.15-7.56, P =0.02) for the occurrence of worsening major depression, dementia or Parkinson's disease in eighty adults age 50 years or older who had experienced prior traumatic brain injury. After adjusting for other covariates, hypertension (HR= 4.15, 95% CI 1.21-14.29, P =0.02) was significant and body mass index (HR=1.14, 95% CI 0.99-1.30; P=0.06) modestly significant predictors of the risk for the time to first occurrence of the composite neurodegenerative outcome. CONCLUSION Type 2 diabetes, hypertension and higher body mass index increase the hazard for the occurrence of worsening depression, Parkinson's disease and dementia following traumatic brain injury in middle-aged and older adults.
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Affiliation(s)
- Mark B. Zimering
- Endocrinology, Veterans Affairs New Jersey Healthcare System, East Orange, NJ
- Rutgers-Robert Wood Johnson Medical School, New Brunswick NJ, USA
| | - Deesha Patel
- Endocrinology, Veterans Affairs New Jersey Healthcare System, East Orange, NJ
| | - Gideon Bahn
- Hines Veterans Affairs Hospital, Hines, Illinois
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Zimering MB. Circulating Neurotoxic 5-HT2A Receptor Agonist Autoantibodies in Adult Type 2 Diabetes with Parkinson's Disease. JOURNAL OF ENDOCRINOLOGY AND DIABETES 2018; 5:10.15226/2374-6890/5/2/01102. [PMID: 29888323 PMCID: PMC5990037 DOI: 10.15226/2374-6890/5/2/01102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AIMS To test whether circulating neurotoxic autoantibodies increase in adult type 2 diabetes mellitus with Parkinson's disease (PD) or dementia. To identify the G-protein coupled receptor on neuroblastoma cells mediating neural inhibitory effects in diabetic Parkinson's disease plasma autoantibodies. To determine the mechanism of accelerated neuroblastoma cell death and acute neurite retraction induced by diabetic Parkinson's disease and dementia autoantibodies. METHODS Protein-A eluates from plasma of twelve older adult male diabetic patients having Parkinson's disease (n=10) or dementia (n=2), and eight age-matched control diabetic patients were tested for ability to cause accelerated N2A neuroblastoma cell death and acute neurite retraction. Specific antagonists of G protein coupled receptors belonging to the G alpha q subfamily of heterotrimetric G-proteins, the phospholipase C/inositol triphosphate/Ca2+ pathway, or the RhoA/Rho kinase pathway were tested for ability to block diabetic Parkinson's disease/dementia autoantibody-induced neurite retraction or N2A accelerated cell loss. Sequential Liposorber LA-15 dextran sulfate cellulose/protein-A affinity chromatography was used to obtain highly-purified fractions of diabetic Parkinson's disease autoantibodies. RESULTS Mean accelerated neuroblastoma cell loss induced by diabetic Parkinson's disease or dementia autoantibodies significantly exceeded (P = 0.001) the level of N2A cell loss induced by an identical concentration of the diabetic autoantibodies in control patients without these two co-morbid neurodegenerative disorders. Co-incubation of diabetic Parkinson's disease and dementia autoantibodies with two-hundred nanomolar concentrations of M100907, a highly selective 5-HT2AR antagonist, completely prevented autoantibody-induced accelerated N2A cell loss and neurite retraction. A higher concentration (500 nM-10μM) of alpha-1 adrenergic, angiotensin II type 1, or endothelin A receptor antagonists did not substantially inhibit autoantibody-induced neuroblastoma cell death or prevent neurite retraction. Antagonists of the inositol triphosphate receptor (2-APB, 50μM), the intracellular calcium chelator (BAPTA-AM, 30 μM) and Y27632 (10 μM), a selective RhoA/Rho kinase inhibitor, each completely blocked acute neurite retraction induced by sixty nanomolar concentrations of diabetic Parkinson's disease autoantibodies. Co-incubation with 2-APB (1-2 μM) for 8 hours' prevented autoantibody-induced N2A cell loss. The highly-purified fraction obtained after Liposorber LA/protein-A affinity chromatography in hypertriglyceridemic diabetic dementia and Parkinson's disease plasmas had apparent MWs > 30 kD, and displayed enhanced N2A toxicity requiring substantially higher concentrations of 5-HT2AR antagonists (M100907, ketanserin, spiperone) to effectively neutralize. CONCLUSION These data suggest increased autoantibodies in older adult diabetes with Parkinson's disease or dementia cause accelerated neuron loss via the 5-hydroxytryptamine 2 receptor coupled to inositol triphosphate receptor-mediated cytosolic Ca2+ release.
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Affiliation(s)
- Mark B. Zimering
- Endocrinology, Veterans Affairs New Jersey Healthcare System, East Orange, NJ & Rutgers/Robert Wood Johnson Medical School, New Brunswick, NJ, USA
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