1
|
Izquierdo-Altarejos P, Arenas YM, Martínez-García M, Vázquez L, Mincheva G, Doverskog M, Blackburn TP, Bohnen NI, Llansola M, Felipo V. Golexanolone reduces glial activation in the striatum and improves non-motor and some motor alterations in a rat model of Parkinson's disease. Front Aging Neurosci 2024; 16:1417938. [PMID: 38974902 PMCID: PMC11224447 DOI: 10.3389/fnagi.2024.1417938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 06/03/2024] [Indexed: 07/09/2024] Open
Abstract
Background Parkinson's disease (PD) affects more than 6 million people worldwide. Along with motor impairments, patients and animal models exhibiting PD symptoms also experience cognitive impairment, fatigue, anxiety, and depression. Currently, there are no drugs available for PD that alter the progression of the disease. A body of evidence suggests that increased GABA levels contribute to the reduced expression of tyrosine hydroxylase (TH) and accompanying behavioral deficits. TH expression may be restored by blocking GABAA receptors. We hypothesized that golexanolone (GR3027), a well-tolerated GABAA receptor-modulating steroid antagonist (GAMSA), may improve Parkinson's symptoms in a rat model of PD. Objectives The aims of this study were to assess whether golexanolone can ameliorate motor and non-motor symptoms in a rat model of PD and to identify some underlying mechanisms. Methods We used the unilateral 6-OHDA rat model of PD. The golexanolone treatment started 4 weeks after surgery. Motor symptoms were assessed using Motorater and CatWalk tests. We also analyzed fatigue (using a treadmill test), anhedonia (via the sucrose preference test), anxiety (with an open field test), and short-term memory (using a Y maze). Glial activation and key proteins involved in PD pathogenesis were analyzed using immunohistochemistry and Western blot. Results Rats with PD showed motor incoordination and impaired locomotor gait, increased fatigue, anxiety, depression, and impaired short-term memory. Golexanolone treatment led to improvements in motor incoordination, certain aspects of locomotor gait, fatigue, anxiety, depression, and short-term memory. Notably, golexanolone reduced the activation of microglia and astrocytes, mitigated TH loss at 5 weeks after surgery, and prevented the increase of α-synuclein levels at 10 weeks. Conclusions Golexanolone may be useful in improving both motor and non-motor symptoms that adversely affect the quality of life in PD patients, such as anxiety, depression, fatigue, motor coordination, locomotor gait, and certain cognitive alterations.
Collapse
Affiliation(s)
| | - Yaiza M. Arenas
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Mar Martínez-García
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Lola Vázquez
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Gergana Mincheva
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | | | | | - Nicolaas I. Bohnen
- Department of Radiology, University of Michigan, Ann Arbor, MI, United States
- Neurology Service and GRECC, Veterans Administration Ann Arbor Healthcare System, Ann Arbor, MI, United States
- Morris K. Udall Center of Excellence for Parkinson's Disease Research, University of Michigan, Ann Arbor, MI, United States
- Parkinson's Foundation Center of Excellence, University of Michigan, Ann Arbor, MI, United States
| | - Marta Llansola
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| |
Collapse
|
2
|
Bäckström T, Doverskog M, Blackburn TP, Scharschmidt BF, Felipo V. Allopregnanolone and its antagonist modulate neuroinflammation and neurological impairment. Neurosci Biobehav Rev 2024; 161:105668. [PMID: 38608826 DOI: 10.1016/j.neubiorev.2024.105668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 03/18/2024] [Accepted: 04/07/2024] [Indexed: 04/14/2024]
Abstract
Neuroinflammation accompanies several brain disorders, either as a secondary consequence or as a primary cause and may contribute importantly to disease pathogenesis. Neurosteroids which act as Positive Steroid Allosteric GABA-A receptor Modulators (Steroid-PAM) appear to modulate neuroinflammation and their levels in the brain may vary because of increased or decreased local production or import from the systemic circulation. The increased synthesis of steroid-PAMs is possibly due to increased expression of the mitochondrial cholesterol transporting protein (TSPO) in neuroinflammatory tissue, and reduced production may be due to changes in the enzymatic activity. Microglia and astrocytes play an important role in neuroinflammation, and their production of inflammatory mediators can be both activated and inhibited by steroid-PAMs and GABA. What is surprising is the finding that both allopregnanolone, a steroid-PAM, and golexanolone, a novel GABA-A receptor modulating steroid antagonist (GAMSA), can inhibit microglia and astrocyte activation and normalize their function. This review focuses on the role of steroid-PAMs in neuroinflammation and their importance in new therapeutic approaches to CNS and liver disease.
Collapse
Affiliation(s)
| | | | | | | | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| |
Collapse
|
3
|
Chen A, Tait C, Minacapelli C, Rustgi V. Pathophysiology of Hepatic Encephalopathy: A Framework for Clinicians. Clin Liver Dis 2024; 28:209-224. [PMID: 38548434 DOI: 10.1016/j.cld.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric syndrome that is observed primarily in patients with liver disease. The pathophysiology is complex and involves many factors including ammonia toxicity, dysregulation of central nervous system activity, and excess inflammatory cytokines. Symptoms of HE range from subclinical to debilitating. HE can be difficult to treat and represents a large burden to patients, their caregivers, and the health-care system because of associated resource utilization. This review article provides an overview of the current understanding of the pathophysiology behind HE and where the current research and treatments are pointing toward.
Collapse
Affiliation(s)
- Alexander Chen
- Internal Medicine, Robert Wood Johnson Medical School, Rutgers Biomedical and Health Sciences (RBHS), Rutgers University, New Brunswick, NJ, USA
| | - Christopher Tait
- Division of Gastroenterology and Hepatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Carlos Minacapelli
- Division of Gastroenterology and Hepatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA; Center for Liver Diseases and Masses, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Vinod Rustgi
- Division of Gastroenterology and Hepatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA; Center for Liver Diseases and Masses, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
| |
Collapse
|
4
|
Bäckström T, Turkmen S, Das R, Doverskog M, Blackburn TP. The GABA system, a new target for medications against cognitive impairment-Associated with neuroactive steroids. J Intern Med 2023; 294:281-294. [PMID: 37518841 DOI: 10.1111/joim.13705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
The prevalence of cognitive dysfunction, dementia, and neurodegenerative disorders such as Alzheimer's disease (AD) is increasing in parallel with an aging population. Distinct types of chronic stress are thought to be instrumental in the development of cognitive impairment in central nervous system (CNS) disorders where cognitive impairment is a major unmet medical need. Increased GABAergic tone is a mediator of stress effects but is also a result of other factors in CNS disorders. Positive GABA-A receptor modulating stress and sex steroids (steroid-PAMs) such as allopregnanolone (ALLO) and medroxyprogesterone acetate can provoke impaired cognition. As such, ALLO impairs memory and learning in both animals and humans. In transgenic AD animal studies, continuous exposure to ALLO at physiological levels impairs cognition and increases degenerative AD pathology, whereas intermittent ALLO injections enhance cognition, indicating pleiotropic functions of ALLO. We have shown that GABA-A receptor modulating steroid antagonists (GAMSAs) can block the acute negative cognitive impairment of ALLO on memory in animal studies and in patients with cognitive impairment due to hepatic encephalopathy. Here we describe disorders affected by steroid-PAMs and opportunities to treat these adverse effects of steroid-PAMs with novel GAMSAs.
Collapse
Affiliation(s)
| | - Sahruh Turkmen
- Department of Clinical Sciences, University of Umeå, Umeå, Sweden
| | - Roshni Das
- Department of Clinical Sciences, University of Umeå, Umeå, Sweden
- Umecrine Cognition AB, Solna, Sweden
| | | | | |
Collapse
|
5
|
Balzano T, Llansola M, Arenas YM, Izquierdo-Altarejos P, Felipo V. Hepatic encephalopathy: investigational drugs in preclinical and early phase development. Expert Opin Investig Drugs 2023; 32:1055-1069. [PMID: 37902074 DOI: 10.1080/13543784.2023.2277386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 10/26/2023] [Indexed: 10/31/2023]
Abstract
INTRODUCTION Hepatic encephalopathy (HE) is a neuropsychiatric syndrome, in patients with liver disease, which affects life quality and span. Current treatments are lactulose or rifaximin, acting on gut microbiota. Treatments aiming ammonia levels reduction have been tested with little success. AREAS COVERED Pre-clinical research shows that the process inducing HE involves sequentially: liver failure, altered microbiome, hyperammonemia, peripheral inflammation, changes in immunophenotype and extracellular vesicles and neuroinflammation, which alters neurotransmission impairing cognitive and motor function. HE may be reversed using drugs acting at any step: modulating microbiota with probiotics or fecal transplantation; reducing peripheral inflammation with anti-TNFα, autotaxin inhibitors or silymarin; reducing neuroinflammation with sulforaphane, p38 MAP kinase or phosphodiesteras 5 inhibitors, antagonists of sphingosine-1-phosphate receptor 2, enhancing meningeal lymphatic drainage or with extracellular vesicles from mesenchymal stem cells; reducing GABAergic neurotransmission with indomethacin or golexanolone. EXPERT OPINION A factor limiting the progress of HE treatment is the lack of translation of research advances into clinical trials. Only drugs acting on microbiota or ammonia reduction have been tested in patients. It is urgent to change the mentality on how to approach HE treatment to develop clinical trials to assess drugs acting on the immune system/peripheral inflammation, neuroinflammation or neurotransmission to improve HE.
Collapse
Affiliation(s)
- Tiziano Balzano
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
- HM CINAC (Centro Integral de Neurociencias Abarca Campal), Hospital Universitario HM Puerta del Sur, HM Hospitales, Madrid, Spain
| | - Marta Llansola
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Yaiza M Arenas
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
- Departamento de Patología, Facultad de Medicina, Universidad Valencia, Valencia, Spain
| | | | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| |
Collapse
|
6
|
Mincheva G, Gimenez-Garzo C, Izquierdo-Altarejos P, Martinez-Garcia M, Doverskog M, Blackburn TP, Hällgren A, Bäckström T, Llansola M, Felipo V. Golexanolone, a GABA A receptor modulating steroid antagonist, restores motor coordination and cognitive function in hyperammonemic rats by dual effects on peripheral inflammation and neuroinflammation. CNS Neurosci Ther 2022; 28:1861-1874. [PMID: 35880480 PMCID: PMC9532914 DOI: 10.1111/cns.13926] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/08/2022] [Accepted: 07/09/2022] [Indexed: 11/29/2022] Open
Abstract
Aims Hyperammonemic rats show peripheral inflammation, increased GABAergic neurotransmission and neuroinflammation in cerebellum and hippocampus which induce motor incoordination and cognitive impairment. Neuroinflammation enhances GABAergic neurotransmission in cerebellum by enhancing the TNFR1‐glutaminase‐GAT3 and TNFR1‐CCL2‐TrkB‐KCC2 pathways. Golexanolone reduces GABAA receptors potentiation by allopregnanolone. This work aimed to assess if treatment of hyperammonemic rats with golexanolone reduces peripheral inflammation and neuroinflammation and restores cognitive and motor function and to analyze underlying mechanisms. Methods Rats were treated with golexanolone and effects on peripheral inflammation, neuroinflammation, TNFR1‐glutaminase‐GAT3 and TNFR1‐CCL2‐TrkB‐KCC2 pathways, and cognitive and motor function were analyzed. Results Hyperammonemic rats show increased TNFα and reduced IL‐10 in plasma, microglia and astrocytes activation in cerebellum and hippocampus, and impaired motor coordination and spatial and short‐term memories. Treating hyperammonemic rats with golexanolone reversed changes in peripheral inflammation, microglia and astrocytes activation and restored motor coordination and spatial and short‐term memory. This was associated with reversal of the hyperammonemia‐enhanced activation in cerebellum of the TNFR1‐glutaminase‐GAT3 and TNFR1‐CCL2‐TrkB‐KCC2 pathways. Conclusion Reducing GABAA receptors activation with golexanolone reduces peripheral inflammation and neuroinflammation and improves cognitive and motor function in hyperammonemic rats. The effects identified would also occur in patients with hepatic encephalopathy and, likely, in other pathologies associated with neuroinflammation.
Collapse
Affiliation(s)
- Gergana Mincheva
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Carla Gimenez-Garzo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | | | - Mar Martinez-Garcia
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | | | | | | | - Torbjörn Bäckström
- Umecrine Cognition AB, Solna, Sweden.,Umeå Neurosteroid Research Center, Clinical Sciences at Umeå University, Umeå, Sweden
| | - Marta Llansola
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| |
Collapse
|
7
|
Bäckström T, Das R, Bixo M. Positive GABA A receptor modulating steroids and their antagonists: Implications for clinical treatments. J Neuroendocrinol 2022; 34:e13013. [PMID: 34337790 DOI: 10.1111/jne.13013] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/09/2021] [Accepted: 07/09/2021] [Indexed: 01/02/2023]
Abstract
GABA is the main inhibitory neurotransmitter in the brain and GABAergic transmission has been shown to be of importance for regulation of mood, memory and food intake. The progesterone metabolite allopregnanolone (Allo) is a positive GABAA receptor modulating steroid with potent effects. In humans, disorders such as premenstrual dysphoric disorder (PMDD), hepatic encephalopathy and polycystic ovarian syndrome are associated with elevated Allo levels and increased negative mood, disturbed memory and increased food intake in some individuals. This is surprising because Allo shares many properties with benzodiazepines and is mainly considered to be anxiolytic and anti-depressant. However, it is well established that, in certain individuals, GABAA receptor activating compounds could have paradoxical effects and thus be anxiogenic in low physiological plasma concentrations but anxiolytic at high levels. We have demonstrated that isoallopregnanolone (Isoallo), the 3β-OH sibling of Allo, functions as a GABAA receptor modulating steroid antagonist (GAMSA) but without any effects of its own on GABAA receptors. The antagonistic effect is noted in most GABAA subtypes investigated in vitro to date. In vivo, Isoallo can inhibit Allo-induced anaesthesia in rats, as well as sedation or saccadic eye velocity in humans. Isoallo treatment has been studied in women with PMDD. In a first phase II study, Isoallo (Sepranolone; Asarina Pharma) injections significantly ameliorated negative mood in women with PMDD compared with placebo. Several GAMSAs for oral administration have also been developed. The GAMSA, UC1011, can inhibit Allo induced memory disturbances in rats and an oral GAMSA, GR3027, has been shown to restore learning and motor coordination in rats with hepatic encephalopathy. In humans, vigilance, cognition and pathological electroencephalogram were improved in patients with hepatic encephalopathy on treatment with GR3027. In conclusion GAMSAs are a new possible treatment for disorders and symptoms caused by hyperactivity in the GABAA system.
Collapse
Affiliation(s)
- Torbjörn Bäckström
- Department of Clinical Sciences, Obstetrics and Gynecology, Umeå University, Umea, Sweden
| | - Roshni Das
- Department of Integrative Medical Biology, Umeå University, Umea, Sweden
| | - Marie Bixo
- Department of Clinical Sciences, Obstetrics and Gynecology, Umeå University, Umea, Sweden
| |
Collapse
|
8
|
Neurosteroid Activation of GABA-A Receptors: A Potential Treatment Target for Symptoms in Primary Biliary Cholangitis? Can J Gastroenterol Hepatol 2022; 2022:3618090. [PMID: 36523650 PMCID: PMC9747297 DOI: 10.1155/2022/3618090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 12/12/2022] Open
Abstract
Background and Aims A third of patients with primary biliary cholangitis (PBC) experience poorly understood cognitive symptoms, with a significant impact on quality of life (QOL), and no effective medical treatment. Allopregnanolone, a neurosteroid, is a positive allosteric modulator of gamma-aminobutyricacid-A (GABA-A) receptors, associated with disordered mood, cognition, and memory. This study explored associations between allopregnanolone and a disease-specific QOL scoring system (PBC-40) in PBC patients. Method Serum allopregnanolone levels were measured in 120 phenotyped PBC patients and 40 age and gender-matched healthy controls. PBC subjects completed the PBC-40 at recruitment. Serum allopregnanolone levels were compared across PBC-40 domains for those with none/mild symptoms versus severe symptoms. Results There were no overall differences in allopregnanolone levels between healthy controls (median = 0.03 ng/ml (IQR = 0.025)) and PBC patients (0.031 (0.42), p = 0.42). Within the PBC cohort, higher allopregnanolone levels were observed in younger patients (r (120) = -0.53, p < 0.001) but not healthy controls (r (39) = -0.21, p = 0.21). Allopregnanolone levels were elevated in the PBC-40 domains, cognition (u = 1034, p = 0.02), emotional (u = 1374, p = 0.004), and itch (u = 795, p = 0.03). Severe cognitive symptoms associated with a younger age: severe (50 (12)) vs. none (60 (13); u = 423 p = 0.001). Conclusion Elevated serum allopregnanolone is associated with severe cognitive, emotional, and itch symptoms in PBC, in keeping with its known action on GABA-A receptors. Existing novel compounds targeting allopregnanolone could offer new therapies in severely symptomatic PBC, satisfying a significant unmet need.
Collapse
|
9
|
A pilot study of golexanolone, a new GABA-A receptor-modulating steroid antagonist, in patients with covert hepatic encephalopathy. J Hepatol 2021; 75:98-107. [PMID: 33894327 DOI: 10.1016/j.jhep.2021.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 01/01/2023]
Abstract
BACKGROUND & AIMS Golexanolone is a novel small molecule GABA-A receptor-modulating steroid antagonist under development for the treatment of cognitive and vigilance disorders caused by allosteric over-activation of GABA-A receptors by neurosteroids. It restored spatial learning and motor coordination in animal models of hepatic encephalopathy (HE) and mitigated the effects of intravenous allopregnanolone in healthy adults in a dose-dependent fashion. Herein, we report data on the safety, pharmacokinetics (PK) and efficacy of golexanolone in adult patients with cirrhosis. METHODS Following single/multiple ascending dose studies, adults with Child-Pugh A/B cirrhosis and abnormal continuous reaction time (CRT) on screening were randomized to 3 weeks' dosing with golexanolone (10, 40 or 80 mg BID) or placebo. CRT, psychometric hepatic encephalopathy score (PHES), animal naming test (ANT), Epworth sleepiness scale (ESS) and electroencephalogram (mean dominant frequency [MDF]; delta+theta/alpha+beta ratio [DT/AB]) were obtained at baseline, 10, and 21 days. RESULTS Golexanolone exhibited satisfactory safety and PK. Baseline characteristics were similar between the 12 and 33 patients randomized to placebo or golexanolone, respectively. By prespecified analyses, golexanolone was associated with directionally favourable changes vs. placebo in ESS (p = 0.047), MDF (p = 0.142) and DT/AB (p = 0.021). All patients also showed directionally favourable changes in CRT, PHES and ANT, but with no statistical difference between golexanolone and placebo. Post hoc analyses taking into account the variability and improvement in CRT, PHES and ANT observed between screening and baseline suggested an efficacy signal by cognitive measures as well. CONCLUSION Golexanolone was well tolerated and associated with improvement in cognitive performance. These results implicate GABA-A receptor-modulating neurosteroids in the pathogenesis of HE and support the therapeutic potential of golexanolone. LAY SUMMARY Many patients with cirrhosis experience subtle but disabling cognitive problems, including sleepiness and poor attention span, that impair their ability to be gainfully employed or carry out activities of daily living. This pilot study tested the hypothesis that these problems with cognition, for which there is no approved treatment, might be improved by an experimental drug, golexanolone, designed to normalize the function of receptors which inhibit brain function. The results of this study suggest that golexanolone is well tolerated and may improve cognition, as reflected by measures of sleepiness, attention span and brain wave activity, paving the way for future larger studies of this promising experimental drug. CLINICAL TRIAL REGISTRATION NUMBER EudraCT 2016-003651-30.
Collapse
|
10
|
Ryu AJ, Rahimi RS, Leise MD. The Current Hepatic Encephalopathy Pipeline. J Clin Exp Hepatol 2020; 10:377-385. [PMID: 32655239 PMCID: PMC7335727 DOI: 10.1016/j.jceh.2020.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 01/06/2020] [Indexed: 02/08/2023] Open
Abstract
Hepatic encephalopathy (HE) is a complication of acute or chronic liver failure; its mechanism is complex, involving multiple organ systems, and is still being elucidated. The standard of care, lactulose, has remained generally unchanged for decades. However, in recent years, better understanding of the pathophysiology has yielded new therapeutic targets for this reversible condition. These novel treatments act both on traditional pathways established in the ammonia hypothesis and through more recently discovered mechanisms. Here, we review contemporary investigational therapies for HE. We used narrative reviews and searched ClinicalTrials.gov database for the condition "hepatic encephalopathy" through August 29, 2019. Our review yielded six key areas of therapeutic focus: (1) antibiotics against urease-producing gut bacteria, (2) intravenous ammonia scavengers, (3) modified synthetic probiotics, (4) fecal microbiota transplant, (5) brain steroid-modulating agents, and 6) nonlactulose laxatives. Active trials are ongoing in each of these therapeutic areas.
Collapse
Key Words
- CHESS, clinical hepatic encephalopathy staging scale
- FMT, fecal microbiota transplant
- HE, hepatic encephalopathy
- HESA, hepatic encephalopathy scoring algorithm
- MAD, multiple-ascending dose
- MES, modified encephalopathy scale
- ORT, object recognition test
- PEG, polyethylene glycol-3350
- SAD, single-ascending dose
- SEV, saccadic eye velocity
- ammonia
- antibiotics
- fecal microbiota transplant
- hepatic encephalopathy
- lactulose
- therapy
- trials
Collapse
Affiliation(s)
- Alexander J. Ryu
- Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, United States
| | - Robert S. Rahimi
- Division of Hepatology, Baylor Scott & White Health, Dallas, TX, United States
| | - Michael D. Leise
- Division of Gastroenterology & Hepatology, Mayo Clinic College of Medicine, Rochester, MN, United States
| |
Collapse
|
11
|
GABA-A receptor modulating steroids in acute and chronic stress; relevance for cognition and dementia? Neurobiol Stress 2019; 12:100206. [PMID: 31921942 PMCID: PMC6948369 DOI: 10.1016/j.ynstr.2019.100206] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/13/2019] [Accepted: 12/18/2019] [Indexed: 01/10/2023] Open
Abstract
Cognitive dysfunction, dementia and Alzheimer's disease (AD) are increasing as the population worldwide ages. Therapeutics for these conditions is an unmet need. This review focuses on the role of the positive GABA-A receptor modulating steroid allopregnanolone (APα), it's role in underlying mechanisms for impaired cognition and of AD, and to determine options for therapy of AD. On one hand, APα given intermittently promotes neurogenesis, decreases AD-related pathology and improves cognition. On the other, continuous exposure of APα impairs cognition and deteriorates AD pathology. The disparity between these two outcomes led our groups to analyze the mechanisms underlying the difference. We conclude that the effects of APα depend on administration pattern and that chronic slightly increased APα exposure is harmful to cognitive function and worsens AD pathology whereas single administrations with longer intervals improve cognition and decrease AD pathology. These collaborative assessments provide insights for the therapeutic development of APα and APα antagonists for AD and provide a model for cross laboratory collaborations aimed at generating translatable data for human clinical trials.
Collapse
|
12
|
Choi Y, Raymer BK. Sleep modulating agents. Bioorg Med Chem Lett 2019; 29:2025-2033. [PMID: 31307886 DOI: 10.1016/j.bmcl.2019.06.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/17/2019] [Accepted: 06/22/2019] [Indexed: 12/28/2022]
Abstract
Sleep and wake are two fundamental states of human existence. Conditions such as insomnia and hypersomnia can have profound negative effects on human health. Many pharmacological interventions impacting sleep and wake are available or are under development. This brief digest surveys early approaches to sleep modulation and highlights recent developments in sleep modulating agents.
Collapse
Affiliation(s)
- Younggi Choi
- Discovery Chemistry, Alkermes, 852 Winter Street, Waltham, MA, United States
| | - Brian K Raymer
- Discovery Research, Alkermes, 852 Winter Street, Waltham, MA, United States.
| |
Collapse
|
13
|
Parakala ML, Zhang Y, Modgil A, Chadchankar J, Vien TN, Ackley MA, Doherty JJ, Davies PA, Moss SJ. Metabotropic, but not allosteric, effects of neurosteroids on GABAergic inhibition depend on the phosphorylation of GABA A receptors. J Biol Chem 2019; 294:12220-12230. [PMID: 31239352 PMCID: PMC6690684 DOI: 10.1074/jbc.ra119.008875] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/28/2019] [Indexed: 11/06/2022] Open
Abstract
Neuroactive steroids (NASs) are synthesized within the brain and exert profound effects on behavior. These effects are primarily believed to arise from the activities of NASs as positive allosteric modulators (PAMs) of the GABA-type A receptor (GABAAR). NASs also activate a family of G protein-coupled receptors known as membrane progesterone receptors (mPRs). Here, using surface-biotinylation assays and electrophysiology techniques, we examined mPRs' role in mediating the effects of NAS on the efficacy of GABAergic inhibition. Selective mPR activation enhanced phosphorylation of Ser-408 and Ser-409 (Ser-408/9) within the GABAAR β3 subunit, which depended on the activity of cAMP-dependent protein kinase A (PKA) and protein kinase C (PKC). mPR activation did not directly modify GABAAR activity and had no acute effects on phasic or tonic inhibition. Instead, mPR activation induced a sustained elevation in tonic current, which was blocked by PKA and PKC inhibition. Substitution of Ser-408/9 to alanine residues also prevented the effects of mPR activation on tonic current. Furthermore, this substitution abolished the effects of sustained NAS exposure on tonic inhibition. Interestingly, the allosteric effects of NAS on GABAergic inhibition were independent of Ser-408/9 in the β3 subunit. Additionally, although allosteric effects of NAS on GABAergic inhibition were sensitive to a recently developed "NAS antagonist," the sustained effects of NAS on tonic inhibition were not. We conclude that metabotropic effects of NAS on GABAergic inhibition are mediated by mPR-dependent modulation of GABAAR phosphorylation. We propose that this mechanism may contribute to the varying behavioral effects of NAS.
Collapse
Affiliation(s)
- Manasa L Parakala
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Yihui Zhang
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Amit Modgil
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Jayashree Chadchankar
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Thuy N Vien
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | | | | | - Paul A Davies
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111; Department of Neuroscience, Physiology, and Pharmacology, University College, London WC1E 6BT, United Kingdom.
| |
Collapse
|
14
|
Coughlin Q, Hopper AT, Blanco MJ, Tirunagaru V, Robichaud AJ, Doller D. Allosteric Modalities for Membrane-Bound Receptors: Insights from Drug Hunting for Brain Diseases. J Med Chem 2019; 62:5979-6002. [PMID: 30721063 DOI: 10.1021/acs.jmedchem.8b01651] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Medicinal chemists are accountable for embedding the appropriate drug target profile into the molecular architecture of a clinical candidate. An accurate characterization of the functional effects following binding of a drug to its biological target is a fundamental step in the discovery of new medicines, informing the translation of preclinical efficacy and safety observations into human trials. Membrane-bound proteins, particularly ion channels and G protein-coupled receptors (GPCRs), are biological targets prone to allosteric modulation. Investigations using allosteric drug candidates and chemical tools suggest that their functional effects may be tailored with a high degree of translational alignment, making them molecular tools to correct pathophysiological functional tone and enable personalized medicine when a causative target-to-disease link is known. We present select examples of functional molecular fine-tuning of allosterism and discuss consequences relevant to drug design.
Collapse
|