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Lu H, Zhang H, Wu Z, Li L. Microbiota-gut-liver-brain axis and hepatic encephalopathy. MICROBIOME RESEARCH REPORTS 2024; 3:17. [PMID: 38841407 PMCID: PMC11149093 DOI: 10.20517/mrr.2023.44] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 01/16/2024] [Accepted: 01/19/2024] [Indexed: 06/07/2024]
Abstract
Hepatic encephalopathy (HE) is a clinical manifestation of neurological and psychiatric abnormalities that are caused by complications of liver dysfunction including hyperammonemia, hyperuricemia, and portal hypertension. Accumulating evidence suggests that HE could be reversed through therapeutic modifications of gut microbiota. Multiple preclinical and clinical studies have indicated that gut microbiome affects the physiological function of the liver, such as the regulation of metabolism, secretion, and immunity, through the gut-liver crosstalk. In addition, gut microbiota also influences the brain through the gut-brain crosstalk, altering its physiological functions including the regulation of the immune, neuroendocrine, and vagal pathways. Thus, key molecules that are involved in the microbiota-gut-liver-brain axis might be able to serve as clinical biomarkers for early diagnosis of HE, and could be effective therapeutic targets for clinical interventions. In this review, we summarize the pathophysiology of HE and further propose approaches modulating the microbiota-gut-liver-brain axis in order to provide a comprehensive understanding of the prevention and potential clinical treatment for HE with a microbiota-targeted therapy.
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Affiliation(s)
| | | | | | - Lanjuan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang, China
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2
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Warepam M, Mishra AK, Sharma GS, Kumari K, Krishna S, Khan MSA, Rahman H, Singh LR. Brain Metabolite, N-Acetylaspartate Is a Potent Protein Aggregation Inhibitor. Front Cell Neurosci 2021; 15:617308. [PMID: 33613199 PMCID: PMC7894078 DOI: 10.3389/fncel.2021.617308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 01/08/2021] [Indexed: 11/17/2022] Open
Abstract
Deposition of toxic protein inclusions is a common hallmark of many neurodegenerative disorders including Alzheimer's disease, Parkinson disease etc. N-acetylaspartate (NAA) is an important brain metabolite whose levels got altered under various neurodegenerative conditions. Indeed, NAA has been a widely accepted biological marker for various neurological disorders. We have also reported that NAA is a protein stabilizer. In the present communication, we investigated the role of NAA in modulating the aggregation propensity on two model proteins (carbonic anhydrase and catalase). We discovered that NAA suppresses protein aggregation and could solubilize preformed aggregates.
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Affiliation(s)
- Marina Warepam
- Department of Biotechnology, Manipur University, Manipur, India
| | | | - Gurumayum Suraj Sharma
- Department of Botany, Bhaskaracharya College of Applied Sciences, University of Delhi, New Delhi, India
| | - Kritika Kumari
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, New Delhi, India
| | - Snigdha Krishna
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, New Delhi, India
| | - Mohd Sajjad Ahmad Khan
- Department of Basic Sciences, Deanship of Preparatory Year and Supporting Studies, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Hamidur Rahman
- Department of Biotechnology, Manipur University, Manipur, India
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Esterline R, Oscarsson J, Burns J. A role for sodium glucose cotransporter 2 inhibitors (SGLT2is) in the treatment of Alzheimer's disease? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2020; 155:113-140. [PMID: 32854852 DOI: 10.1016/bs.irn.2020.03.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
With the lack of success and increasing urgency for therapies capable of impacting Alzheimer's disease (AD) and its progression, there are increasing efforts to expand testing of new mechanistic hypotheses to attack the disease from different angles. Three such hypotheses are the "Mitochondrial Cascade (MC)" hypothesis, the "Endo-Lysosomal Dysfunction (ELD)" hypothesis and the "Type 3 Diabetes (T3D)" hypothesis. These hypotheses provide a rationale for new pharmacological approaches to address the mitochondrial, endo-lysosomal and metabolic dysfunction associated with AD. It is increasingly evident that there is critical interplay between the metabolic dysfunction associated with obesity/metabolic syndrome/type 2 diabetes mellitus (T2DM) and patient susceptibility to AD development. A candidate for a common mechanism linking these metabolically-driven disease states is chronically-activated mechanistic target of rapamycin (mTOR) signaling. Unrestrained chronic mTOR activation may be responsible for sustaining metabolic, lysosomal and mitochondrial dysfunction in AD, driving both the breakdown of the blood-brain barrier via endothelial cell dysfunction and hyperphosphorylation of tau and formation of amyloid plaques in the brain. It is hypothesized that sodium glucose cotransporter 2 (SGLT2) inhibition, mediated by sustained glucose loss, restores mTOR cycling through nutrient-driven, nightly periods of transient mTOR inhibition (and restoration of catabolic cellular housekeeping processes) interspersed by daily periods of transient mTOR activation (and anabolism) accompanying eating. In this way, a flexible mTOR dynamic is restored, thereby preventing or even reducing the progress of AD pathology. The first study to investigate the effect of SGLT2 inhibition in patients with AD is ongoing and focuses on the impact on energy metabolism in the brain following treatment with the SGLT2 inhibitor dapagliflozin.
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Affiliation(s)
- Russell Esterline
- BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, United States.
| | - Jan Oscarsson
- BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Jeffrey Burns
- University of Kansas Alzheimer's Disease Center, Kansas City, KS, United States
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Warepam M, Ahmad K, Rahman S, Rahaman H, Kumari K, Singh LR. N-Acetylaspartate Is an Important Brain Osmolyte. Biomolecules 2020; 10:biom10020286. [PMID: 32059525 PMCID: PMC7072545 DOI: 10.3390/biom10020286] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/29/2020] [Accepted: 02/08/2020] [Indexed: 01/11/2023] Open
Abstract
Most of the human diseases related to various proteopathies are confined to the brain, which leads to the development of various forms of neurological disorders. The human brain consists of several osmolytic compounds, such as N-Acetylaspartate (NAA), myo-inositol (mI), glutamate (Glu), glutamine (Gln), creatine (Cr), and choline-containing compounds (Cho). Among these osmolytes, the level of NAA drastically decreases under neurological conditions, and, hence, NAA is considered to be one of the most widely accepted neuronal biomarkers in several human brain disorders. To date, no data are available regarding the effect of NAA on protein stability, and, therefore, the possible effect of NAA under proteopathic conditions has not been fully uncovered. To gain an insight into the effect of NAA on protein stability, thermal denaturation and structural measurements were carried out using two model proteins at different pH values. The results indicate that NAA increases the protein stability with an enhancement of structure formation. We also observed that the stabilizing ability of NAA decreases in a pH-dependent manner. Our study indicates that NAA is an efficient protein stabilizer at a physiological pH.
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Affiliation(s)
- Marina Warepam
- Department of Biotechnology, Manipur University, Manipur 795003, India; (M.W.); (H.R.)
| | - Khurshid Ahmad
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Korea;
| | - Safikur Rahman
- Department of Botany, Munshi Singh College, BR Ambedkar Bihar University, Muzaffarpur, Bihar 845401, India;
| | - Hamidur Rahaman
- Department of Biotechnology, Manipur University, Manipur 795003, India; (M.W.); (H.R.)
| | - Kritika Kumari
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India;
| | - Laishram Rajendrakumar Singh
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India;
- Correspondence: ; Tel.: +91-9811630757; Fax: +91-11-27666248
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Kavanaugh BC, Warren EB, Baytas O, Schmidt M, Merck D, Buch K, Liu JS, Phornphutkul C, Caruso P, Morrow EM. Longitudinal MRI findings in patient with SLC25A12 pathogenic variants inform disease progression and classification. Am J Med Genet A 2019; 179:2284-2291. [PMID: 31403263 PMCID: PMC6788951 DOI: 10.1002/ajmg.a.61322] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 11/10/2022]
Abstract
Aspartate-glutamate carrier 1 (AGC1) is one of two exchangers within the malate-aspartate shuttle. AGC1 is encoded by the SLC25A12 gene. Three patients with pathogenic variants in SLC25A12 have been reported in the literature. These patients were clinically characterized by neurodevelopmental delay, epilepsy, hypotonia, cerebral atrophy, and hypomyelination; however, there has been discussion in the literature as to whether this hypomyelination is primary or secondary to a neuronal defect. Here we report a 12-year-old patient with variants in SLC25A12 and magnetic resonance imaging (MRI) at multiple ages. Novel compound heterozygous, recessive variants in SLC25A12 were identified: c.1295C>T (p.A432V) and c.1447-2_1447-1delAG. Clinical presentation is characterized by severe intellectual disability, nonambulatory, nonverbal status, hypotonia, epilepsy, spastic quadriplegia, and a happy disposition. The serial neuroimaging findings are notable for cerebral atrophy with white matter involvement, namely, early hypomyelination yet subsequent progression of myelination. The longitudinal MRI findings are most consistent with a leukodystrophy of the leuko-axonopathy category, that is, white matter abnormalities that are most suggestive of mechanisms that result from primary neuronal defects. We present here the first case of a patient with compound heterozygous variants in SLC25A12, including brain MRI findings, in the oldest individual reported to date with this neurogenetic condition.
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Affiliation(s)
- Brian C Kavanaugh
- Developmental Disorders Genetics Research Program, Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University and Emma Pendleton Bradley Hospital, East Providence, Rhode Island.,Hassenfeld Child Health Innovation Institute, Brown University, Providence, Rhode Island
| | - Emily B Warren
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Ozan Baytas
- Developmental Disorders Genetics Research Program, Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University and Emma Pendleton Bradley Hospital, East Providence, Rhode Island.,Hassenfeld Child Health Innovation Institute, Brown University, Providence, Rhode Island.,Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Michael Schmidt
- Developmental Disorders Genetics Research Program, Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University and Emma Pendleton Bradley Hospital, East Providence, Rhode Island.,Hassenfeld Child Health Innovation Institute, Brown University, Providence, Rhode Island.,Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Derek Merck
- Department of Diagnostic Imaging, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Karen Buch
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Judy S Liu
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island.,Department of Neurology, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Providence, Rhode Island.,Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, Rhode Island
| | - Chanika Phornphutkul
- Department of Pediatrics, Division of Human Genetics, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Paul Caruso
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Eric M Morrow
- Developmental Disorders Genetics Research Program, Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University and Emma Pendleton Bradley Hospital, East Providence, Rhode Island.,Hassenfeld Child Health Innovation Institute, Brown University, Providence, Rhode Island.,Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island.,Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, Rhode Island
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Costigan AG, Umla-Runge K, Evans CJ, Hodgetts CJ, Lawrence AD, Graham KS. Neurochemical correlates of scene processing in the precuneus/posterior cingulate cortex: A multimodal fMRI and 1 H-MRS study. Hum Brain Mapp 2019; 40:2884-2898. [PMID: 30865358 PMCID: PMC6563468 DOI: 10.1002/hbm.24566] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/07/2018] [Accepted: 02/15/2019] [Indexed: 12/18/2022] Open
Abstract
Precuneus/posterior cingulate cortex (PCu/PCC) are key components of a midline network, activated during rest but also in tasks that involve construction of scene or situation models. Despite growing interest in PCu/PCC functional alterations in disease and disease risk, the underlying neurochemical modulators of PCu/PCC's task‐evoked activity are largely unstudied. Here, a multimodal imaging approach was applied to investigate whether interindividual differences in PCu/PCC fMRI activity, elicited during perceptual discrimination of scene stimuli, were correlated with local brain metabolite levels, measured during resting‐state 1H‐MRS. Forty healthy young adult participants completed an fMRI perceptual odd‐one‐out task for scenes, objects and faces. 1H‐MRS metabolites N‐acetyl‐aspartate (tNAA), glutamate (Glx) and γ‐amino‐butyric acid (GABA+) were quantified via PRESS and MEGA‐PRESS scans in a PCu/PCC voxel and an occipital (OCC) control voxel. Whole brain fMRI revealed a cluster in right dorsal PCu/PCC that showed a greater BOLD response to scenes versus faces and objects. When extracted from an independently defined PCu/PCC region of interest, scene activity (vs. faces and objects and also vs. baseline) was positively correlated with PCu/PCC, but not OCC, tNAA. A voxel‐wise regression analysis restricted to the PCu/PCC 1H‐MRS voxel area identified a significant PCu/PCC cluster, confirming the positive correlation between scene‐related BOLD activity and PCu/PCC tNAA. There were no correlations between PCu/PCC activity and Glx or GABA+ levels. These results demonstrate, for the first time, that scene activity in PCu/PCC is linked to local tNAA levels, identifying a neurochemical influence on interindividual differences in the task‐driven activity of a key brain hub.
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Affiliation(s)
- Alison G Costigan
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Wales, UK
| | - Katja Umla-Runge
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Wales, UK
| | - C John Evans
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Wales, UK
| | - Carl J Hodgetts
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Wales, UK
| | - Andrew D Lawrence
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Wales, UK
| | - Kim S Graham
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Wales, UK
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