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Tsai CY, Lee CL, Wu JCC. Astrocyte-secreted lipocalin-2 elicits bioenergetic failure-induced neuronal death that is causally related to high fatality in a mouse model of hepatic encephalopathy. Neurochem Int 2024; 178:105800. [PMID: 38964718 DOI: 10.1016/j.neuint.2024.105800] [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: 02/26/2024] [Revised: 06/24/2024] [Accepted: 07/01/2024] [Indexed: 07/06/2024]
Abstract
Hepatic encephalopathy (HE) is a neurological complication arising from acute liver failure with poor prognosis and high mortality; the underlying cellular mechanisms are still wanting. We previously found that neuronal death caused by mitochondrial dysfunction in rostral ventrolateral medulla (RVLM), which leads to baroreflex dysregulation, is related to high fatality in an animal model of HE. Lipocalin-2 (Lcn2) is a secreted glycoprotein mainly released by astrocytes in the brain. We noted the presence of Lcn2 receptor (Lcn2R) in RVLM neurons and a parallel increase of Lcn2 gene in astrocytes purified from RVLM during experimental HE. Therefore, our guiding hypothesis is that Lcn2 secreted by reactive astrocytes in RVLM may underpin high fatality during HE by eliciting bioenergetic failure-induced neuronal death in this neural substrate. In this study, we first established the role of astrocyte-secreted Lcn2 in a liver toxin model of HE induced by azoxymethane (100 μg/g, ip) in C57BL/6 mice, followed by mechanistic studies in primary astrocyte and neuron cultures prepared from postnatal day 1 mouse pups. In animal study, immunoneutralization of Lcn2 reduced apoptotic cell death in RVLM, reversed defunct baroreflex-mediated vasomotor tone and prolonged survival during experimental HE. In our primary cell culture experiments, Lcn2 produced by cultured astrocytes and released into the astrocyte-conditioned medium significantly reduced cell viability of cultured neurons. Recombinant Lcn2 protein reduced cell viability, mitochondrial ATP (mitoATP) production, and pyruvate dehydrogenase (PDH) activity but enhanced the expression of pyruvate dehydrogenase kinase (PDK) 1, PDK3 and phospho-PDHA1 (inactive PDH) through MAPK/ERK pathway in cultured neurons, with all cellular actions reversed by Lcn2R knockdown. Our results suggest that astrocyte-secreted Lcn2 upregulates PDKs through MAPK/ERK pathway, which leads to reduced PDH activity and mitoATP production; the reinforced neuronal death in RVLM is causally related to baroreflex dysregulation that underlies high fatality associated with HE.
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Affiliation(s)
- Ching-Yi Tsai
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
| | - Chin-Lai Lee
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Jacqueline C C Wu
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
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Zhang H, Xu J. Unveiling thioacetamide-induced toxicity: Multi-organ damage and omitted bone toxicity. Hum Exp Toxicol 2024; 43:9603271241241807. [PMID: 38531387 DOI: 10.1177/09603271241241807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Thioacetamide (TAA), a widely employed hepatotoxic substance, has gained significant traction in the induction of liver failure disease models. Upon administration of TAA to experimental animals, the production of potent oxidative derivatives ensues, culminating in the activation of oxidative stress and subsequent infliction of severe damage upon multiple organs via dissemination through the bloodstream. This review summarized the various organ damages and corresponding mechanistic explanations observed in previous studies using TAA in toxicological animal experiments. The principal pathological consequences arising from TAA exposure encompass oxidative stress, inflammation, lipid peroxidation, fibrosis, apoptosis induction, DNA damage, and osteoclast formation. Recent in vivo and in vitro studies on TAA bone toxicity have confirmed that long-term high-dose use of TAA not only induces liver damage in experimental animals but also accompanies bone damage, which was neglected for a long time. By using TAA to model diseases in experimental animals and controlling TAA dosage, duration of use, and animal exposure environment, we can induce various organ injury models. It should be noted that TAA-induced injuries have a time-dependent effect. Finally, in our daily lives, especially for researchers, we should take precautions to minimize TAA exposure and reduce the probability of related organ injuries.
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Affiliation(s)
- Haodong Zhang
- School of Medical Technology and Information Engineering, Zhejiang Chinese Medical University, Hangzhou, P.R. China
| | - Jian Xu
- School of Medical Technology and Information Engineering, Zhejiang Chinese Medical University, Hangzhou, P.R. China
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3
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Niknahad H, Mobasheri A, Arjmand A, Rafiei E, Alidaee S, Razavi H, Bagheri S, Rezaei H, Sabouri S, Najibi A, Khodaei F, Kashani SMA, Ommati MM, Heidari R. Hepatic encephalopathy complications are diminished by piracetam via the interaction between mitochondrial function, oxidative stress, inflammatory response, and locomotor activity. Heliyon 2023; 9:e20557. [PMID: 37810869 PMCID: PMC10551565 DOI: 10.1016/j.heliyon.2023.e20557] [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: 04/12/2023] [Revised: 09/01/2023] [Accepted: 09/28/2023] [Indexed: 10/10/2023] Open
Abstract
Background of the study: Hepatic encephalopathy (HE) is a complication in which brain ammonia (NH4+) levels reach critically high concentrations because of liver failure. HE could lead to a range of neurological complications from locomotor and behavioral disturbances to coma. Several tactics have been established for subsiding blood and brain NH4+. However, there is no precise intervention to mitigate the direct neurological complications of NH4+. Purpose It has been found that oxidative stress, mitochondrial damage, and neuro-inflammation play a fundamental role in NH4+ neurotoxicity. Piracetam is a drug used clinically in neurological complications such as stroke and head trauma. Piracetam could significantly diminish oxidative stress and improve brain mitochondrial function. Research methods In the current study, piracetam (100 and 500 mg/kg, oral) was used in a mice model of HE induced by thioacetamide (TA, 800 mg/kg, single dose, i.p). Results Significant disturbances in animals' locomotor activity, along with increased oxidative stress biomarkers, including reactive oxygen species formation, protein carbonylation, lipid peroxidation, depleted tissue glutathione, and decreased antioxidant capacity, were evident in the brain of TA-treated mice. Meanwhile, mitochondrial permeabilization, mitochondrial depolarization, suppression of dehydrogenases activity, and decreased ATP levels were found in the brain of the TA group. The level of pro-inflammatory cytokines was also significantly high in the brain of HE animals. Conclusion It was found that piracetam significantly enhanced mice's locomotor activity, blunted oxidative stress biomarkers, decreased inflammatory cytokines, and improved mitochondrial indices in hyperammonemic mice. These data suggest piracetam as a neuroprotective agent which could be repurposed for the management of HE.
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Affiliation(s)
- Hossein Niknahad
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali Mobasheri
- Research Unit of Medical Imaging, Physics, And Technology, Faculty of Medicine, University of Oulu, FI-90014, Oulu, Finland
- University Medical Center Utrecht, Departments of Orthopedics Rheumatology and Clinical Immunology, 3508, GA, Utrecht, the Netherlands
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08406, Vilnius, Lithuania
| | - Abdollah Arjmand
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elahe Rafiei
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sepideh Alidaee
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hadi Razavi
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sara Bagheri
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Heresh Rezaei
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Samira Sabouri
- Shanxi Key Laboratory of Ecological, Animal Sciences, And Environmental Veterinary Medicine, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Asma Najibi
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Forouzan Khodaei
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyyed Mohammad Amin Kashani
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Mehdi Ommati
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Shanxi Key Laboratory of Ecological, Animal Sciences, And Environmental Veterinary Medicine, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
- Henan Key Laboratory of Environmental and Animal Product Safety, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, Henan, China
| | - Reza Heidari
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Ramakrishna K, Sinku S, Majumdar S, Singh N, Gajendra TA, Rani A, Krishnamurthy S. Indole-3-carbinol ameliorated the thioacetamide-induced hepatic encephalopathy in rats. Toxicology 2023; 492:153542. [PMID: 37150287 DOI: 10.1016/j.tox.2023.153542] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 05/09/2023]
Abstract
Indole-3-carbinol (I3C) is reported to have hepatic and neuroprotective properties. However, the I3C role in the protection of the liver and brain in the pathological condition of hepatic encephalopathy has not been investigated. Therefore, in the present study, we have assessed the hepatic and neuroprotective roles of I3C against thioacetamide (TAA)- induced hepatic encephalopathy in Wistar rats. TAA (300mg/kg) was intraperitoneally administered to Wistar rats to induce hepatic encephalopathy. The elevated levels of ammonia in the blood, liver, and brain were substantially lowered by I3C treatment (25, 50, and 100mg/kg, oral, 7 days). I3C significantly ameliorated the TAA-induced liver dysfunction by decreasing the alanine transaminase, aspartate transaminase, and alkaline phosphatase enzymes and reduced the elevated cytochrome P4502E1 (CYP2E1) activity in the liver and brain. Further, I3C alleviated mitochondrial dysfunction and oxidative stress in the brain. I3C treatment improved the anti-inflammatory cytokine interleukin (IL)-10 while reducing inflammatory cytokines such as tumor necrosis factor-1 and IL-6 in hepatic encephalopathy rats. I3C reduced the levels of apoptotic indicators mediated by the mitochondria, including cytochrome c, caspase 9, and caspase 3. Concurrently, I3C mitigated the liver and brain histological abnormalities in hepatic encephalopathy rats. Therefore, the present study concluded that the I3C protected the liver and brain from TAA-induced hepatic encephalopathy injury by inhibiting CYP2E1 enzyme activity and decreasing ammonia, oxidative stress, inflammation, and apoptosis. The present study provides preclinical validation of I3C use as hepatic and neuroprotective for hepatic encephalopathy management.
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Affiliation(s)
- Kakarla Ramakrishna
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University (IIT BHU), Varanasi, Uttar Pradesh, India; Department of Pharmacy, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Andhra Pradesh, India
| | - Sangeetha Sinku
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University (IIT BHU), Varanasi, Uttar Pradesh, India
| | - Shreyasi Majumdar
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University (IIT BHU), Varanasi, Uttar Pradesh, India
| | - Neha Singh
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University (IIT BHU), Varanasi, Uttar Pradesh, India
| | - T A Gajendra
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University (IIT BHU), Varanasi, Uttar Pradesh, India
| | - Asha Rani
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University (IIT BHU), Varanasi, Uttar Pradesh, India
| | - Sairam Krishnamurthy
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University (IIT BHU), Varanasi, Uttar Pradesh, India.
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Chemical Profile of Cyperus laevigatus and Its Protective Effects against Thioacetamide-Induced Hepatorenal Toxicity in Rats. Molecules 2022; 27:molecules27196470. [PMID: 36235007 PMCID: PMC9573427 DOI: 10.3390/molecules27196470] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/21/2022] [Accepted: 09/27/2022] [Indexed: 11/17/2022] Open
Abstract
Cyperus species represent a group of cosmopolitan plants used in folk medicine to treat several diseases. In the current study, the phytochemical profile of Cyperus laevigatus ethanolic extract (CLEE) was assessed using UPLC-QTOF-MS/MS. The protective effect of CLEE at 50 and 100 mg /kg body weight (b.w.) was evaluated on hepatorenal injuries induced by thioacetamide (100 mg/kg) via investigation of the extract's effects on oxidative stress, inflammatory markers and histopathological changes in the liver and kidney. UPLC-QTOF-MS/MS analysis of CLEE resulted in the identification of 94 compounds, including organic and phenolic acids, flavones, aurones, and fatty acids. CLEE improved the antioxidant status in the liver and kidney, as manifested by enhancement of reduced glutathione (GSH) and coenzyme Q10 (CoQ10), in addition to the reduction in malondialdehyde (MDA), nitric oxide (NO), and 8-hydroxy-2'-deoxyguanosine (8OHdG). Moreover, CLEE positively affected oxidative stress parameters in plasma and thwarted the depletion of hepatorenal ATP content by thioacetamide (TAA). Furthermore, treatment of rats with CLEE alleviated the significant increase in plasma liver enzymes, kidney function parameters, and inflammatory markers. The protective effect of CLEE was confirmed by a histopathological study of the liver and kidney. Our results proposed that CLEE may reduce TAA-hepatorenal toxicity via its antioxidant and anti-inflammatory properties suppressing oxidative stress.
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Zielińska M, Albrecht J, Popek M. Dysregulation of Astrocytic Glutamine Transport in Acute Hyperammonemic Brain Edema. Front Neurosci 2022; 16:874750. [PMID: 35733937 PMCID: PMC9207324 DOI: 10.3389/fnins.2022.874750] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022] Open
Abstract
Acute liver failure (ALF) impairs ammonia clearance from blood, which gives rise to acute hyperammonemia and increased ammonia accumulation in the brain. Since in brain glutamine synthesis is the only route of ammonia detoxification, hyperammonemia is as a rule associated with increased brain glutamine content (glutaminosis) which correlates with and contributes along with ammonia itself to hyperammonemic brain edema-associated with ALF. This review focuses on the effects of hyperammonemia on the two glutamine carriers located in the astrocytic membrane: Slc38a3 (SN1, SNAT3) and Slc7a6 (y + LAT2). We emphasize the contribution of the dysfunction of either of the two carriers to glutaminosis- related aspects of brain edema: retention of osmotically obligated water (Slc38a3) and induction of oxidative/nitrosative stress (Slc7a6). The changes in glutamine transport link glutaminosis- evoked mitochondrial dysfunction to oxidative-nitrosative stress as formulated in the “Trojan Horse” hypothesis.
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Buler M, Naessens T, Mattsson J, Morias Y, Söderberg M, Robbins P, Kärrberg L, Svensson TS, Thulin P, Glinghammar B, Scarpulla RC, Andersson U. The regulatory role of PGC1α-related coactivator in response to drug-induced liver injury. FASEB Bioadv 2020; 2:453-463. [PMID: 32821877 PMCID: PMC7429352 DOI: 10.1096/fba.2020-00003] [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: 01/13/2020] [Revised: 01/13/2020] [Accepted: 05/28/2020] [Indexed: 11/24/2022] Open
Abstract
PGC1α-Related Coactivator (PRC) is a transcriptional coactivator promoting cytokine expression in vitro in response to mitochondrial injury and oxidative stress, however, its physiological role has remained elusive. Herein we investigate aspects of the immune response function of PRC, first in an in vivo thioacetamide (TAA)-induced mouse model of drug-induced liver injury (DILI), and subsequently in vitro in human monocytes, HepG2, and dendritic (DC) cells. TAA treatment resulted in the dose-dependent induction of PRC mRNA and protein, both of which were shown to correlate with liver injury markers. Conversely, an adenovirus-mediated knockdown of PRC attenuated this response, thereby reducing hepatic cytokine mRNA expression and monocyte infiltration. Subsequent in vitro studies with conditioned media from HepG2 cells overexpressing PRC, activated human monocytes and monocyte-derived DC, demonstrated up to 20% elevated expression of CD86, CD40, and HLA-DR. Similarly, siRNA-mediated knockdown of PRC abolished this response in oligomycin stressed HepG2 cells. A putative mechanism was suggested by the co-immunoprecipitation of Signal Transducer and Activator of Transcription 1 (STAT1) with PRC, and induction of a STAT-dependent reporter. Furthermore, PRC co-activated an NF-κB-dependent reporter, indicating interaction with known major inflammatory factors. In summary, our study indicates PRC as a novel factor modulating inflammation in DILI.
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Affiliation(s)
- Marcin Buler
- Clinical Pharmacology and Safety SciencesAstraZeneca R&DMölndalSweden
| | - Thomas Naessens
- Clinical Pharmacology and Safety SciencesAstraZeneca R&DMölndalSweden
| | - Johan Mattsson
- Clinical Pharmacology and Safety SciencesAstraZeneca R&DMölndalSweden
| | - Yannick Morias
- Clinical Pharmacology and Safety SciencesAstraZeneca R&DMölndalSweden
| | - Magnus Söderberg
- Clinical Pharmacology and Safety SciencesAstraZeneca R&DMölndalSweden
| | | | - Lillevi Kärrberg
- Clinical Pharmacology and Safety SciencesAstraZeneca R&DMölndalSweden
| | - Tor S. Svensson
- Clinical Pharmacology and Safety SciencesAstraZeneca R&DMölndalSweden
| | - Petra Thulin
- Clinical Pharmacology and Safety SciencesAstraZeneca R&DMölndalSweden
| | - Björn Glinghammar
- Science for Life LaboratoryDrug Discovery & Development Platform & Division of Translational Medicine & Chemical BiologyDepartment of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
| | | | - Ulf Andersson
- Clinical Pharmacology and Safety SciencesAstraZeneca R&DMölndalSweden
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Heidari R. Brain mitochondria as potential therapeutic targets for managing hepatic encephalopathy. Life Sci 2019; 218:65-80. [DOI: 10.1016/j.lfs.2018.12.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/08/2018] [Accepted: 12/16/2018] [Indexed: 02/07/2023]
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Dhanda S, Sunkaria A, Halder A, Sandhir R. Mitochondrial dysfunctions contribute to energy deficits in rodent model of hepatic encephalopathy. Metab Brain Dis 2018; 33:209-223. [PMID: 29138968 DOI: 10.1007/s11011-017-0136-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/12/2017] [Indexed: 12/12/2022]
Abstract
Perturbations in the cerebral energy metabolism are anticipated to be an important factor by which ammonia may exert its toxic effects on the central nervous system. The present study was designed to investigate the role of impaired mitochondrial functions and cerebral energy metabolism in the development hepatic encephalopathy (HE) induced by of bile duct ligation (BDL). After four weeks of BDL, a significant increase in hepatic hydroxyproline and collagen content was observed which confirmed biliary fibrosis. Brain regions viz. cortex, hippocampus, striatum and cerebellum of BDL rats had impaired activity of mitochondrial respiratory chain enzymes. This was accompanied by increase in mitochondrial reactive oxygen species (ROS), malondialdehyde (MDA) and protein carbonyl levels in the brain. Mitochondrial redox ratio was significantly reduced in the brain of BDL rats. In addition, mitochondria from brain of BDL rats were depolarized and swollen compared to the sham controls. Ultrastructure analysis of mitochondria from cortex and hippocampus of BDL animals revealed aberrant cristae, ruptured membranes and non-dense matrix. Further, a significant decrease was observed in creatine kinase activity, glucose uptake and CO2 production in the brain regions of BDL rats. ATP/ADP ratio, a critical parameter of cellular energy status, was also significantly reduced in brain regions of rats with HE. Overall, the findings clearly demonstrate that BDL induced HE involves mitochondrial respiratory chain dysfunctions, mitochondrial depolarization and swelling that accentuates oxidative stress which in turn leads to compromise in cerebral energy metabolism thereby contributing to the pathophysiology of chronic HE.
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Affiliation(s)
- Saurabh Dhanda
- Department of Biochemistry, Panjab University, Basic Medical Science Block-II, Sector-25, Chandigarh, 160014, India
| | - Aditya Sunkaria
- Department of Biochemistry, Panjab University, Basic Medical Science Block-II, Sector-25, Chandigarh, 160014, India
| | - Avishek Halder
- Department of Biochemistry, Panjab University, Basic Medical Science Block-II, Sector-25, Chandigarh, 160014, India
| | - Rajat Sandhir
- Department of Biochemistry, Panjab University, Basic Medical Science Block-II, Sector-25, Chandigarh, 160014, India.
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Witt AM, Larsen FS, Bjerring PN. Accumulation of lactate in the rat brain during hyperammonaemia is not associated with impaired mitochondrial respiratory capacity. Metab Brain Dis 2017; 32:461-470. [PMID: 27928693 DOI: 10.1007/s11011-016-9934-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 11/29/2016] [Indexed: 01/27/2023]
Abstract
In acute liver failure (ALF) cerebral oedema and high intracranial pressure (ICP) are potentially deadly complications. Astrocytes cultured in ammonia have shown mitochondrial dysfunction and in rat models of liver failure, de novo lactate production in the brain has been observed and has led to a hypothesis of compromised brain metabolism during ALF. In contrast, normal lactate levels are found in cerebral microdialysate of ALF patients and the oxygen: glucose ratio of cerebral metabolic rates remains normal. To investigate this inconsistency we studied the mitochondrial function in brain tissue with respirometry in animal models of hyperammonaemia. Wistar rats with systemic inflammation induced by lipopolysaccharide or liver insufficiency induced by 90% hepatectomy were given ammonium or sodium acetate for 120 min. A cerebral cortex homogenate was studied with respirometry and substrates of the citric acid cycle, uncouplers and inhibitors of the mitochondrial complexes were successively added to investigate the mitochondrial function in detail. In a separate dose-response experiment cortex from healthy rats was incubated for 120 min in ammonium acetate in concentrations up to 80 mM prior to respirometry. Hyperammonaemia was associated with elevated ICP and increased tissue lactate concentration. No difference between groups was found in total respiratory capacity or the function of individual mitochondrial complexes. Ammonium in concentrations of 40 and 80 mM reduced the respiratory capacity in vitro. In conclusion, acute hyperammonaemia leads to elevated ICP and cerebral lactate accumulation. We found no indications of impaired oxidative metabolism in vivo but only in vitro at extreme concentrations of ammonium.
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Affiliation(s)
- Anne Møller Witt
- Department of Hepatology, Rigshospitalet, DK-2100, Copenhagen, Denmark
| | - Fin Stolze Larsen
- Department of Hepatology, Rigshospitalet, DK-2100, Copenhagen, Denmark
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Hartman JH, Miller GP, Meyer JN. Toxicological Implications of Mitochondrial Localization of CYP2E1. Toxicol Res (Camb) 2017; 6:273-289. [PMID: 28989700 DOI: 10.1039/c7tx00020k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cytochrome P450 2E1 (CYP2E1) metabolizes an extensive array of pollutants, drugs, and other small molecules, often resulting in bioactivation to reactive metabolites. Therefore, it is unsurprising that it has been the subject of decades of research publications and reviews. However, while CYP2E1 has historically been studied in the endoplasmic reticulum (erCYP2E1), active CYP2E1 is also present in mitochondria (mtCYP2E1). Relatively few studies have specifically focused on mtCYP2E1, but there is growing interest in this form of the enzyme as a driver in toxicological mechanisms given its activity and location. Many previous studies have linked total CYP2E1 to conditions that involve mitochondrial dysfunction (fasting, diabetes, non-alcoholic steatohepatitis, and obesity). Furthermore, a large number of reactive metabolites that are formed by CYP2E1 through metabolism of drugs and pollutants have been demonstrated to cause mitochondrial dysfunction. Finally, there appears to be significant inter-individual variability in targeting to the mitochondria, which could constitute a source of variability in individual response to exposures. This review discusses those outcomes, the biochemical properties and toxicological consequences of mtCYP2E1, and highlights important knowledge gaps and future directions. Overall, we feel that this exciting area of research is rich with new and important questions about the relationship between mtCYP2E1, mitochondrial dysfunction, and pathology.
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Affiliation(s)
| | - Grover P Miller
- Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR
| | - Joel N Meyer
- Nicholas School of the Environment, Duke University, Durham, NC
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12
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Ammonia-induced miRNA expression changes in cultured rat astrocytes. Sci Rep 2016; 6:18493. [PMID: 26755400 PMCID: PMC4709596 DOI: 10.1038/srep18493] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 11/19/2015] [Indexed: 12/20/2022] Open
Abstract
Hepatic encephalopathy is a neuropsychiatric syndrome evolving from cerebral osmotic disturbances and oxidative/nitrosative stress. Ammonia, the main toxin of hepatic encephalopathy, triggers astrocyte senescence in an oxidative stress-dependent way. As miRNAs are critically involved in cell cycle regulation and their expression may be regulated by oxidative stress, we analysed, whether astrocyte senescence is a consequence of ammonia-induced miRNA expression changes. Using a combined miRNA and gene microarray approach, 43 miRNA species which were downregulated and 142 genes which were upregulated by NH4Cl (5 mmol/l, 48 h) in cultured rat astrocytes were found. Ammonia-induced miRNA and gene expression changes were validated by qPCR and 43 potential miRNA target genes, including HO-1, were identified by matching upregulated mRNA species with predicted targets of miRNA species downregulated by ammonia. Inhibition of HO-1 targeting miRNAs which were downregulated by NH4Cl strongly upregulated HO-1 mRNA and protein levels and inhibited astrocyte proliferation in a HO-1-dependent way. Preventing ammonia-induced upregulation of HO-1 by taurine (5 mmol/l) as well as blocking HO-1 activity by tin-protoporphyrine IX fully prevented ammonia-induced proliferation inhibition and senescence. The data suggest that ammonia induces astrocyte senescence through NADPH oxidase-dependent downregulation of HO-1 targeting miRNAs and concomitant upregulation of HO-1 at both mRNA and protein level.
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Stefanello ST, Flores da Rosa EJ, Dobrachinski F, Amaral GP, Rodrigues de Carvalho N, Almeida da Luz SC, Bender CR, Schwab RS, Dornelles L, Soares FAA. Effect of diselenide administration in thioacetamide-induced acute neurological and hepatic failure in mice. Toxicol Res (Camb) 2015. [DOI: 10.1039/c4tx00166d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hepatic encephalopathy is a common complication of severe acute hepatic failure and has been associated with high short-term mortality rates.
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KOBLIHOVÁ E, MRÁZOVÁ I, VERNEROVÁ Z, RYSKA M. Acute Liver Failure Induced by Thioacetamide: Selection of Optimal Dosage in Wistar and Lewis Rats. Physiol Res 2014; 63:491-503. [DOI: 10.33549/physiolres.932690] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Acute liver failure (ALF) is a clinical condition with very high mortality rate. Its pathophysiological background is still poorly understood, which necessitates a search for optimal experimental ALF models with features resembling those of the human disorder. Taking into consideration reproducibility of induction of ALF, adequate animal size, cost of animals, the required time gap between insult and death of animals (“therapeutic window”), potential risk to investigator and other aspects, administration of thioacetamide (TAA) in rats is currently most recommended. However, the fundamental details of this ALF model have not yet been evaluated. This prompted us to investigate, first, the course of ALF as induced by intraperitoneal TAA at doses increasing from 175 to 700 mg/kg BW per day. The animals’ survival rate, plasma alanine and aspartate aminotransferase activities, and bilirubin and ammonia levels were determined over the follow-up period. Second, we examined whether Wistar and Lewis rats exhibit any differences in the course of ALF induced by different TAA doses. We found that the optimal dose for ALF induction in rats is 350 mg.kg-1 i.p., given as a single injection. Wistar rats proved more susceptible to the development of TAA-induced ALF compared with Lewis rats. Collectively, our present findings provide a sound methodological background for experimental studies aimed at evaluation of pathophysiology and development of new approaches in the therapy of ALF.
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Affiliation(s)
- E. KOBLIHOVÁ
- Department of Surgery, Second Faculty of Medicine, Charles University and Central Military Hospital, Prague, Czech Republic
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Farjam M, Mehrabani D, Abbassnia F, Tanideh N, Imanieh MH, Pakbaz S, Ashraf MJ, Panjehshahin MR, Dehdab S. The healing effect of Curcuma longa on liver in experimental acute hepatic encephalopathy of rat. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s00580-014-1883-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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