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Samuvel DJ, Lemasters JJ, Chou CJ, Zhong Z. LP340, a novel histone deacetylase inhibitor, decreases liver injury and fibrosis in mice: role of oxidative stress and microRNA-23a. Front Pharmacol 2024; 15:1386238. [PMID: 38828459 PMCID: PMC11140137 DOI: 10.3389/fphar.2024.1386238] [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: 02/14/2024] [Accepted: 04/24/2024] [Indexed: 06/05/2024] Open
Abstract
Effective therapy for liver fibrosis is lacking. Here, we examined whether LP340, the lead candidate of a new-generation of hydrazide-based HDAC1,2,3 inhibitors (HDACi), decreases liver fibrosis. Liver fibrosis was induced by CCl4 treatment and bile duct ligation (BDL) in mice. At 6 weeks after CCl4, serum alanine aminotransferase increased, and necrotic cell death and leukocyte infiltration occurred in the liver. Tumor necrosis factor-α and myeloperoxidase markedly increased, indicating inflammation. After 6 weeks, α-smooth muscle actin (αSMA) and collagen-1 expression increased by 80% and 575%, respectively, indicating hepatic stellate cell (HSC) activation and fibrogenesis. Fibrosis detected by trichrome and Sirius-red staining occurred primarily in pericentral regions with some bridging fibrosis in liver sections. 4-Hydroxynonenal adducts (indicator of oxidative stress), profibrotic cytokine transforming growth factor-β (TGFβ), and TGFβ downstream signaling molecules phospho-Smad2/3 also markedly increased. LP340 attenuated indices of liver injury, inflammation, and fibrosis markedly. Moreover, Ski-related novel protein-N (SnoN), an endogenous inhibitor of TGFβ signaling, decreased, whereas SnoN expression suppressor microRNA-23a (miR23a) increased markedly. LP340 (0.05 mg/kg, ig., daily during the last 2 weeks of CCl4 treatment) decreased 4-hydroxynonenal adducts and miR23a production, blunted SnoN decreases, and inhibited the TGFβ/Smad signaling. By contrast, LP340 had no effect on matrix metalloproteinase-9 expression. LP340 increased histone-3 acetylation but not tubulin acetylation, indicating that LP340 inhibited Class-I but not Class-II HDAC in vivo. After BDL, focal necrosis, inflammation, ductular reactions, and portal and bridging fibrosis occurred at 2 weeks, and αSMA and collagen-1 expression increased by 256% and 560%, respectively. LP340 attenuated liver injury, ductular reactions, inflammation, and liver fibrosis. LP340 also decreased 4-hydroxynonenal adducts and miR23a production, prevented SnoN decreases, and inhibited the TGFβ/Smad signaling after BDL. In vitro, LP340 inhibited immortal human hepatic stellate cells (hTERT-HSC) activation in culture (αSMA and collagen-1 expression) as well as miR23a production, demonstrating its direct inhibitory effects on HSC. In conclusions, LP340 is a promising therapy for both portal and pericentral liver fibrosis, and it works by inhibiting oxidative stress and decreasing miR23a.
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Affiliation(s)
- Devadoss J. Samuvel
- Departments of Drug Discovery and Biomedical Sciences, Charleston, SC, United States
| | - John J. Lemasters
- Departments of Drug Discovery and Biomedical Sciences, Charleston, SC, United States
- Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, United States
| | - C. James Chou
- Departments of Drug Discovery and Biomedical Sciences, Charleston, SC, United States
- Lydex Pharmaceuticals, Mount Pleasant, SC, United States
| | - Zhi Zhong
- Departments of Drug Discovery and Biomedical Sciences, Charleston, SC, United States
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Nsengimana B, Okpara ES, Hou W, Yan C, Han S. Involvement of oxidative species in cyclosporine-mediated cholestasis. Front Pharmacol 2022; 13:1004844. [DOI: 10.3389/fphar.2022.1004844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/24/2022] [Indexed: 11/10/2022] Open
Abstract
Cyclosporine is an established medication for the prevention of transplant rejection. However, adverse consequences such as nephrotoxicity, hepatotoxicity, and cholestasis have been associated with prolonged usage. In cyclosporine-induced obstructive and chronic cholestasis, for example, the overproduction of oxidative stress is significantly increased. Additionally, cyclosporine exerts adverse effects on liver function and redox balance responses in treated rats, as evidenced by its increasing levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and bilirubin while also decreasing the levels of glutathione and NADPH. Cyclosporine binds to cyclophilin to produce its therapeutic effects, and the resulting complex inhibits calcineurin, causing calcium to accumulate in the mitochondria. Accumulating calcium with concomitant mitochondrial abnormalities induces oxidative stress, perturbation in ATP balance, and failure of calcium pumps. Also, cyclosporine-induced phagocyte oxidative stress generation via the interaction of phagocytes with Toll-like receptor-4 has been studied. The adverse effect of cyclosporine may be amplified by the release of mitochondrial DNA, mediated by oxidative stress-induced mitochondrial damage. Given the uncertainty surrounding the mechanism of cyclosporine-induced oxidative stress in cholestasis, we aim to illuminate the involvement of oxidative stress in cyclosporine-mediated cholestasis and also explore possible strategic interventions that may be applied in the future.
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Samuvel DJ, Li L, Krishnasamy Y, Gooz M, Takemoto K, Woster PM, Lemasters JJ, Zhong Z. Mitochondrial depolarization after acute ethanol treatment drives mitophagy in living mice. Autophagy 2022; 18:2671-2685. [PMID: 35293288 PMCID: PMC9629059 DOI: 10.1080/15548627.2022.2046457] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 12/15/2022] Open
Abstract
Ethanol increases hepatic mitophagy driven by unknown mechanisms. Type 1 mitophagy sequesters polarized mitochondria for nutrient recovery and cytoplasmic remodeling. In Type 2, mitochondrial depolarization (mtDepo) initiates mitophagy to remove the damaged organelles. Previously, we showed that acute ethanol administration produces reversible hepatic mtDepo. Here, we tested the hypothesis that ethanol-induced mtDepo initiates Type 2 mitophagy. GFP-LC3 transgenic mice were gavaged with ethanol (2-6 g/kg) with and without pre-treatment with agents that decrease or increase mtDepo-Alda-1, tacrolimus, or disulfiram. Without ethanol, virtually all hepatocytes contained polarized mitochondria with infrequent autophagic GFP-LC3 puncta visualized by intravital microscopy. At ~4 h after ethanol treatment, mtDepo occurred in an all-or-none fashion within individual hepatocytes, which increased dose dependently. GFP-LC3 puncta increased in parallel, predominantly in hepatocytes with mtDepo. Mitochondrial PINK1 and PRKN/parkin also increased. After covalent labeling of mitochondria with MitoTracker Red (MTR), GFP-LC3 puncta encircled MTR-labeled mitochondria after ethanol treatment, directly demonstrating mitophagy. GFP-LC3 puncta did not associate with fat droplets visualized with BODIPY558/568, indicating that increased autophagy was not due to lipophagy. Before ethanol administration, rhodamine-dextran (RhDex)-labeled lysosomes showed little association with GFP-LC3. After ethanol treatment, TFEB (transcription factor EB) translocated to nuclei, and lysosomal mass increased. Many GFP-LC3 puncta merged with RhDex-labeled lysosomes, showing autophagosomal processing into lysosomes. After ethanol treatment, disulfiram increased, whereas Alda-1 and tacrolimus decreased mtDepo, and mitophagy changed proportionately. In conclusion, mtDepo after acute ethanol treatment induces mitophagic sequestration and subsequent lysosomal processing.Abbreviations : AcAld, acetaldehyde; ADH, alcohol dehydrogenase; ALDH, aldehyde dehydrogenase; ALD, alcoholic liver disease; Alda-1, N-(1,3-benzodioxol-5-ylmethyl)-2,6-dichlorobenzamide; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GFP, green fluorescent protein; LAMP1, lysosomal-associated membrane protein 1; LMNB1, lamin B1; MAA, malondialdehyde-acetaldehyde adducts; MAP1LC3/LC3, microtubule-associated protein 1 light chain 3; MPT, mitochondrial permeability transition; mtDAMPS, mitochondrial damage-associated molecular patterns; mtDepo, mitochondrial depolarization; mtDNA, mitochondrial DNA; MTR, MitoTracker Red; PI, propidium iodide; PINK1, PTEN induced putative kinase 1; PRKN, parkin; RhDex, rhodamine dextran; TFEB, transcription factor EB; Tg, transgenic; TMRM, tetramethylrhodamine methylester; TOMM20, translocase of outer mitochondrial membrane 20; VDAC, voltage-dependent anion channel.
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Affiliation(s)
- Devadoss J. Samuvel
- Departments of Drug Discovery & Biomedical Science, Medical University of South Carolin, Charleston, SC, USA
| | - Li Li
- Departments of Drug Discovery & Biomedical Science, Medical University of South Carolin, Charleston, SC, USA
| | - Yasodha Krishnasamy
- Departments of Drug Discovery & Biomedical Science, Medical University of South Carolin, Charleston, SC, USA
| | - Monika Gooz
- Departments of Drug Discovery & Biomedical Science, Medical University of South Carolin, Charleston, SC, USA
| | - Kenji Takemoto
- Departments of Drug Discovery & Biomedical Science, Medical University of South Carolin, Charleston, SC, USA
| | - Patrick M. Woster
- Departments of Drug Discovery & Biomedical Science, Medical University of South Carolin, Charleston, SC, USA
| | - John J. Lemasters
- Departments of Drug Discovery & Biomedical Science, Medical University of South Carolin, Charleston, SC, USA
- Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Zhi Zhong
- Departments of Drug Discovery & Biomedical Science, Medical University of South Carolin, Charleston, SC, USA
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Samuvel DJ, Nguyen NT, Jaeschke H, Lemasters JJ, Wang X, Choo YM, Hamann MT, Zhong Z. Platanosides, a Potential Botanical Drug Combination, Decrease Liver Injury Caused by Acetaminophen Overdose in Mice. JOURNAL OF NATURAL PRODUCTS 2022; 85:1779-1788. [PMID: 35815804 PMCID: PMC9788857 DOI: 10.1021/acs.jnatprod.2c00324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Oxidative stress plays an important role in acetaminophen (APAP)-induced hepatotoxicity. Platanosides (PTSs) isolated from the American sycamore tree (Platanus occidentalis) represent a potential new four-molecule botanical drug class of antibiotics active against drug-resistant infectious disease. Preliminary studies have suggested that PTSs are safe and well tolerated and have antioxidant properties. The potential utility of PTSs in decreasing APAP hepatotoxicity in mice in addition to an assessment of their potential with APAP for the control of infectious diseases along with pain and pyrexia associated with a bacterial infection was investigated. On PTS treatment in mice, serum alanine aminotransferase (ALT) release, hepatic centrilobular necrosis, and 4-hydroxynonenal (4-HNE) were markedly decreased. In addition, inducible nitric oxide synthase (iNOS) expression and c-Jun-N-terminal kinase (JNK) activation decreased when mice overdosed with APAP were treated with PTSs. Computational studies suggested that PTSs may act as JNK-1/2 and Keap1-Nrf2 inhibitors and that the isomeric mixture could provide greater efficacy than the individual molecules. Overall, PTSs represent promising botanical drugs for hepatoprotection and drug-resistant bacterial infections and are effective in protecting against APAP-related hepatotoxicity, which decreases liver necrosis and inflammation, iNOS expression, and oxidative and nitrative stresses, possibly by preventing persistent JNK activation.
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Affiliation(s)
- Devadoss J. Samuvel
- Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Nga T. Nguyen
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS, United States
| | - Hartmut Jaeschke
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS, United States
| | - John J. Lemasters
- Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States
- Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, United States
| | - Xiaojuan Wang
- School of Pharmacy, Lanzhou University, Lanzhou, Gansu, People Republic of China
| | - Yeun-Mun Choo
- Chemistry Department, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Mark T. Hamann
- Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Zhi Zhong
- Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States
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Cai SY, Yu D, Soroka CJ, Wang J, Boyer JL. Hepatic NFAT signaling regulates the expression of inflammatory cytokines in cholestasis. J Hepatol 2021; 74:550-559. [PMID: 33039404 PMCID: PMC7897288 DOI: 10.1016/j.jhep.2020.09.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 09/18/2020] [Accepted: 09/24/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND & AIMS The nuclear factor of activated T-cells (NFAT) plays an important role in immune responses by regulating the expression of inflammatory genes. However, it is not known whether NFAT plays any role in the bile acid (BA)-induced hepatic inflammatory response. Thus, we aimed to examine the functional role of NFATc3 in cholestatic liver injury in mice and humans. METHODS Gene and protein expression and cellular localization were assessed in primary hepatocyte cultures (mouse and human) and cholestatic liver tissues (murine models and patients with primary biliary cholangitis [PBC] or primary sclerosing cholangitis [PSC]) by quantitative PCR, western blot and immunohistochemistry. Specific NFAT inhibitors were used in vivo and in vitro. Gene reporter assays and ChIP-PCR were used to determine promoter activity. RESULTS NFAT isoforms c1 and c3 were expressed in human and mouse hepatocytes. When treated with cholestatic levels of BAs, nuclear translocation of NFATc3 was increased in both human and mouse hepatocytes and was associated with elevated mRNA levels of IL-8, CXCL2, and CXCL10 in these cells. Blocking NFAT activation with pathway-specific inhibitors or knocking down Nfatc3 expression significantly decreased BA-driven induction of these cytokines in mouse hepatocytes. Nuclear expression of NFATc3/Nfatc3 protein was increased in cholestatic livers, both in mouse models (bile duct ligation or Abcb4-/- mice) and in patients with PBC and PSC in association with elevated tissue levels of Cxcl2 (mice) or IL-8 (humans). Gene reporter assays and ChIP-PCR demonstrated that the NFAT response element in the IL-8 promoter played a key role in BA-induced human IL-8 expression. Finally, blocking NFAT activation in vivo in Abcb4-/- mice reduced cholestatic liver injury. CONCLUSIONS NFAT plays an important role in BA-stimulated hepatic cytokine expression in cholestasis. Blocking hepatic NFAT activation may reduce cholestatic liver injury in humans. LAY SUMMARY Bile acid induces liver injury by stimulating the expression of inflammatory genes in hepatocytes through activation of the transcription factor NFAT. Blocking this activation in vitro (in hepatocyte cultures) and in vivo (in cholestatic mice) decreased the expression of inflammatory genes and reduced liver injury.
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Affiliation(s)
- Shi-Ying Cai
- Department of Internal Medicine, Liver Center, Yale University School of Medicine, New Haven, CT 06520.
| | - Dongke Yu
- Department of Internal Medicine, Liver Center, Yale University School of Medicine, New Haven, CT 06520
| | - Carol J Soroka
- Department of Internal Medicine, Liver Center, Yale University School of Medicine, New Haven, CT 06520
| | - Jing Wang
- Department of Internal Medicine, Liver Center, Yale University School of Medicine, New Haven, CT 06520
| | - James L Boyer
- Department of Internal Medicine, Liver Center, Yale University School of Medicine, New Haven, CT 06520.
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Ure DR, Trepanier DJ, Mayo PR, Foster RT. Cyclophilin inhibition as a potential treatment for nonalcoholic steatohepatitis (NASH). Expert Opin Investig Drugs 2019; 29:163-178. [DOI: 10.1080/13543784.2020.1703948] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Daren R. Ure
- Hepion Pharmaceuticals Inc, Edmonton, AB, Canada
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7
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Wimborne HJ, Takemoto K, Woster PM, Rockey DC, Lemasters JJ, Zhong Z. Aldehyde dehydrogenase-2 activation by Alda-1 decreases necrosis and fibrosis after bile duct ligation in mice. Free Radic Biol Med 2019; 145:136-145. [PMID: 31557514 PMCID: PMC6880805 DOI: 10.1016/j.freeradbiomed.2019.09.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 09/11/2019] [Accepted: 09/22/2019] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND AIM Liver fibrosis is a leading cause of mortality worldwide. Oxidative stress is a key component in the pathogenesis of liver fibrosis. We investigated the role of aldehyde formation resulting from lipid peroxidation in cholestatic liver injury and fibrosis. METHODS C57Bl/6J mice underwent bile duct ligation (BDL) or sham operation. One hour after surgery and daily thereafter, animals were given Alda-1 (20 mg/kg, s.c.), an aldehyde dehydrogenase-2 activator, or equivalent volume of vehicle. Blood and livers were collected after 3 and 14 days. RESULTS Serum alanine aminotransferase (ALT) increased from 39.8 U/L after sham operation to 537 U/L 3 days after BDL, which Alda-1 decreased to 281 U/L. Biliary infarcts with a periportal distribution developed with an area of 7.8% at 14 days after BDL versus 0% area after sham operation. Alda-1 treatment with BDL decreased biliary infarcts to 1.9%. Fibrosis detected by picrosirius red staining increased from 1.6% area in sham to 7.3% after BDL, which decreased to 3.8% with Alda-1. Alda-1 suppression of fibrosis was additionally confirmed by second harmonic generation microscopy. After BDL, collagen-I mRNA increased 12-fold compared to sham, which decreased to 6-fold after Alda-1 treatment. Smooth muscle α-actin expression in the liver, a marker of activated stellate cells, increased from 1% area in sham to 18.7% after BDL, which decreased to 5.3% with Alda-1. CD68-positive macrophages increased from 33.4 cells/field in sham to 134.5 cells/field after BDL, which decreased to 64.9 cells/field with Alda-1. Lastly, 4-hydroxynonenal adduct (4-HNE) immunofluorescence increased from 2.5% area in sham to 14.1% after BDL. Alda-1 treatment decreased 4-HNE to 2.2%. CONCLUSION Accelerated aldehyde degradation by Alda-1 decreases BDL-induced liver necrosis, inflammation, and fibrosis, implying that aldehydes play an important role in the pathogenesis of cholestatic liver injury and fibrosis.
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Affiliation(s)
- Hereward J Wimborne
- Center for Cell Death, Injury & Regeneration, Medical University of South Carolina, Charleston, SC, 29425, United States; Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, United States
| | - Kenji Takemoto
- Center for Cell Death, Injury & Regeneration, Medical University of South Carolina, Charleston, SC, 29425, United States; Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, United States
| | - Patrick M Woster
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, United States
| | - Don C Rockey
- Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, United States
| | - John J Lemasters
- Center for Cell Death, Injury & Regeneration, Medical University of South Carolina, Charleston, SC, 29425, United States; Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, United States; Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, 29425, United States; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, 29425, United States
| | - Zhi Zhong
- Center for Cell Death, Injury & Regeneration, Medical University of South Carolina, Charleston, SC, 29425, United States; Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, United States.
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Evaluation of NV556, a Novel Cyclophilin Inhibitor, as a Potential Antifibrotic Compound for Liver Fibrosis. Cells 2019; 8:cells8111409. [PMID: 31717385 PMCID: PMC6912624 DOI: 10.3390/cells8111409] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 10/31/2019] [Accepted: 11/06/2019] [Indexed: 12/21/2022] Open
Abstract
Hepatic fibrosis can result as a pathological response to nonalcoholic steatohepatitis (NASH). Cirrhosis, the late stage of fibrosis, has been linked to poor survival and an increased risk of developing hepatocellular carcinoma, with limited treatment options available. Therefore, there is an unmet need for novel effective antifibrotic compounds. Cyclophilins are peptidyl-prolyl cis-trans isomerases that facilitate protein folding and conformational changes affecting the function of the targeted proteins. Due to their activity, cyclophilins have been presented as key factors in several stages of the fibrotic process. In this study, we investigated the antifibrotic effects of NV556, a novel potent sanglifehrin-based cyclophilin inhibitor, in vitro and in vivo. NV556 potential antifibrotic effect was evaluated in two well-established animal models of NASH, STAM, and methionine-choline-deficient (MCD) mice, as well as in an in vitro 3D human liver ECM culture of LX2 cells, a human hepatic stellate cell line. We demonstrate that NV556 decreased liver fibrosis in both STAM and MCD in vivo models and decreased collagen production in TGFβ1-activated hepatic stellate cells in vitro. Taken together, these results present NV556 as a potential candidate for the treatment of liver fibrosis.
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Krishnasamy Y, Gooz M, Li L, Lemasters JJ, Zhong Z. Role of mitochondrial depolarization and disrupted mitochondrial homeostasis in non-alcoholic steatohepatitis and fibrosis in mice. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2019; 11:190-204. [PMID: 31777643 PMCID: PMC6872485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 09/10/2019] [Indexed: 06/10/2023]
Abstract
The pathogenesis of non-alcoholic steatohepatitis (NASH) is poorly understood. Here, relationships between mitochondrial depolarization (mtDepo) and mitochondrial homeostasis were studied in a mouse model of NASH. C57BL/6 mice were fed a Western diet (high fat, fructose and cholesterol) for 2 weeks, 2 months and 6 months, and livers were harvested for histology and biochemical analysis. Hepatic mtDepo was evaluated by intravital multiphoton microscopy. After Western diet feeding, mixed hepatic micro- and macrovesicular steatosis and leukocyte infiltration occurred at 2 weeks and continued to increase afterwards. ALT release, mild necrosis, apoptosis, and ballooning degeneration were present at 2 and 6 months. Smooth muscle α-actin expression increased at 2 weeks and longer, and increased collagen-I expression and mild fibrosis occurred at 6 months. After feeding Western diet for 2 weeks and longer, mtDepo appeared in 50-70% hepatocytes, indicating mitochondrial dysfunction at an early stage of NASH. mtDepo can initiate mitophagy, and mitophagic markers increased at 2 and 6 months. Concurrently autophagic processing became impaired. Oxidative phosphorylation proteins, mitochondrial biogenesis signals, and proteins associated with mitochondrial fission and fusion decreased after 2 months and longer of Western diet. Proinflammatory and profibrotic signaling (NLRP3 inflammasome activation, expression of IL-1, osteopontin and TGF-β1) also increased in association with mitochondrial stress/dysfunction after Western diet feeding. Taken together, we show that hepatic mtDepo occurs early in mice fed a Western diet, followed by increased mitophagic burden, suppressed mitochondrial biogenesis and dynamics, and mitochondrial depletion. These novel mitochondrial alterations in NASH most likely play an important role in promoting steatosis, inflammation, and progression to fibrosis.
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Affiliation(s)
- Yasodha Krishnasamy
- Department of Drug Discovery and Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
| | - Monika Gooz
- Department of Drug Discovery and Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
| | - Li Li
- Department of Drug Discovery and Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
| | - John J Lemasters
- Department of Drug Discovery and Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
- Department of Biochemistry and Molecular Biology, Medical University of South CarolinaCharleston, SC 29425, USA
| | - Zhi Zhong
- Department of Drug Discovery and Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
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Kuo J, Bobardt M, Chatterji U, Mayo PR, Trepanier DJ, Foster RT, Gallay P, Ure DR. A Pan-Cyclophilin Inhibitor, CRV431, Decreases Fibrosis and Tumor Development in Chronic Liver Disease Models. J Pharmacol Exp Ther 2019; 371:231-241. [PMID: 31406003 PMCID: PMC6815936 DOI: 10.1124/jpet.119.261099] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 08/01/2019] [Indexed: 12/14/2022] Open
Abstract
Previous studies show that cyclophilins contribute to many pathologic processes, and cyclophilin inhibitors demonstrate therapeutic activities in many experimental models. However, no drug with cyclophilin inhibition as the primary mode of action has advanced completely through clinical development to market. In this study, we present findings on the cyclophilin inhibitor, CRV431, that highlight its potential as a drug candidate for chronic liver diseases. CRV431 was found to potently inhibit all cyclophilin isoforms tested—A, B, D, and G. Inhibitory constant or IC50 values ranged from 1 to 7 nM, which was up to 13 times more potent than the parent compound, cyclosporine A (CsA), from which CRV431 was derived. Other CRV431 advantages over CsA as a nontransplant drug candidate were significantly diminished immunosuppressive activity, less drug transporter inhibition, and reduced cytotoxicity potential. Oral dosing to mice and rats led to good blood exposures and a 5- to 15-fold accumulation of CRV431 in liver compared with blood concentrations across a wide range of CRV431 dosing levels. Most importantly, CRV431 decreased liver fibrosis in a 6-week carbon tetrachloride model and in a mouse model of nonalcoholic steatohepatitis (NASH). Additionally, CRV431 administration during a late, oncogenic stage of the NASH disease model resulted in a 50% reduction in the number and size of liver tumors. These findings are consistent with CRV431 targeting fibrosis and cancer through multiple, cyclophilin-mediated mechanisms and support the development of CRV431 as a safe and effective drug candidate for liver diseases.
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Affiliation(s)
- Joseph Kuo
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, California (J.K., M.B., U.C., P.G.); and Hepion Pharmaceuticals, Edison, New Jersey (P.R.M., D.J.T., R.T.F., D.R.U.)
| | - Michael Bobardt
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, California (J.K., M.B., U.C., P.G.); and Hepion Pharmaceuticals, Edison, New Jersey (P.R.M., D.J.T., R.T.F., D.R.U.)
| | - Udayan Chatterji
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, California (J.K., M.B., U.C., P.G.); and Hepion Pharmaceuticals, Edison, New Jersey (P.R.M., D.J.T., R.T.F., D.R.U.)
| | - Patrick R Mayo
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, California (J.K., M.B., U.C., P.G.); and Hepion Pharmaceuticals, Edison, New Jersey (P.R.M., D.J.T., R.T.F., D.R.U.)
| | - Daniel J Trepanier
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, California (J.K., M.B., U.C., P.G.); and Hepion Pharmaceuticals, Edison, New Jersey (P.R.M., D.J.T., R.T.F., D.R.U.)
| | - Robert T Foster
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, California (J.K., M.B., U.C., P.G.); and Hepion Pharmaceuticals, Edison, New Jersey (P.R.M., D.J.T., R.T.F., D.R.U.)
| | - Philippe Gallay
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, California (J.K., M.B., U.C., P.G.); and Hepion Pharmaceuticals, Edison, New Jersey (P.R.M., D.J.T., R.T.F., D.R.U.)
| | - Daren R Ure
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, California (J.K., M.B., U.C., P.G.); and Hepion Pharmaceuticals, Edison, New Jersey (P.R.M., D.J.T., R.T.F., D.R.U.)
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Wang H, Liang X, Gravot G, Thorling CA, Crawford DHG, Xu ZP, Liu X, Roberts MS. Visualizing liver anatomy, physiology and pharmacology using multiphoton microscopy. JOURNAL OF BIOPHOTONICS 2017; 10:46-60. [PMID: 27312349 DOI: 10.1002/jbio.201600083] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 05/18/2016] [Indexed: 05/09/2023]
Abstract
Multiphoton microscopy (MPM) has become increasingly popular and widely used in both basic and clinical liver studies over the past few years. This technology provides insights into deep live tissues with less photobleaching and phototoxicity, which helps us to better understand the cellular morphology, microenvironment, immune responses and spatiotemporal dynamics of drugs and therapeutic cells in the healthy and diseased liver. This review summarizes the principles, opportunities, applications and limitations of MPM in hepatology. A key emphasis is on the use of fluorescence lifetime imaging (FLIM) to add additional quantification and specificity to the detection of endogenous fluorescent species in the liver as well as exogenous molecules and nanoparticles that are applied to the liver in vivo. We anticipate that in the near future MPM-FLIM will advance our understanding of the cellular and molecular mechanisms of liver diseases, and will be evaluated from bench to bedside, leading to real-time histology of human liver diseases.
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Affiliation(s)
- Haolu Wang
- Therapeutics Research Centre, School of Medicine, The University of Queensland, Princess Alexandra Hospital, Woolloongabba, QLD 4102, Australia
| | - Xiaowen Liang
- Therapeutics Research Centre, School of Medicine, The University of Queensland, Princess Alexandra Hospital, Woolloongabba, QLD 4102, Australia
| | - Germain Gravot
- Department of Pharmacy, University of Rennes 1, Ille-et-Vilaine, Rennes, 35043, France
| | - Camilla A Thorling
- Therapeutics Research Centre, School of Medicine, The University of Queensland, Princess Alexandra Hospital, Woolloongabba, QLD 4102, Australia
| | - Darrell H G Crawford
- School of Medicine, The University of Queensland, Gallipoli Medical Research Foundation, Greenslopes Private Hospital, Greenslopes, QLD 4120, Australia
| | - Zhi Ping Xu
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Xin Liu
- Therapeutics Research Centre, School of Medicine, The University of Queensland, Princess Alexandra Hospital, Woolloongabba, QLD 4102, Australia
| | - Michael S Roberts
- Therapeutics Research Centre, School of Medicine, The University of Queensland, Princess Alexandra Hospital, Woolloongabba, QLD 4102, Australia
- School of Pharmacy and Medical Science, University of South Australia, Adelaide, SA 5001, Australia
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Wende AR, Young ME, Chatham J, Zhang J, Rajasekaran NS, Darley-Usmar VM. Redox biology and the interface between bioenergetics, autophagy and circadian control of metabolism. Free Radic Biol Med 2016; 100:94-107. [PMID: 27242268 PMCID: PMC5124549 DOI: 10.1016/j.freeradbiomed.2016.05.022] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 05/25/2016] [Accepted: 05/26/2016] [Indexed: 12/01/2022]
Abstract
Understanding molecular mechanisms that underlie the recent emergence of metabolic diseases such as diabetes and heart failure has revealed the need for a multi-disciplinary research integrating the key metabolic pathways which change the susceptibility to environmental or pathologic stress. At the physiological level these include the circadian control of metabolism which aligns metabolism with temporal demand. The mitochondria play an important role in integrating the redox signals and metabolic flux in response to the changing activities associated with chronobiology, exercise and diet. At the molecular level this involves dynamic post-translational modifications regulating transcription, metabolism and autophagy. In this review we will discuss different examples of mechanisms which link these processes together. An important pathway capable of linking signaling to metabolism is the post-translational modification of proteins by O-linked N-acetylglucosamine (O-GlcNAc). This is a nutrient regulated protein modification that plays an important role in impaired cellular stress responses. Circadian clocks have also emerged as critical regulators of numerous cardiometabolic processes, including glucose/lipid homeostasis, hormone secretion, redox status and cardiovascular function. Central to these pathways are the response of autophagy, bioenergetics to oxidative stress, regulated by Keap1/Nrf2 and mechanisms of metabolic control. The extension of these ideas to the emerging concept of bioenergetic health will be discussed.
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Affiliation(s)
- Adam R Wende
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Martin E Young
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - John Chatham
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jianhua Zhang
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Namakkal S Rajasekaran
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Victor M Darley-Usmar
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA; UAB Mitochondrial Medicine Laboratory, University of Alabama at Birmingham, Birmingham, AL, USA; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
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Krishnasamy Y, Ramshesh VK, Gooz M, Schnellmann RG, Lemasters JJ, Zhong Z. Ethanol and High Cholesterol Diet Causes Severe Steatohepatitis and Early Liver Fibrosis in Mice. PLoS One 2016; 11:e0163342. [PMID: 27676640 PMCID: PMC5038945 DOI: 10.1371/journal.pone.0163342] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/07/2016] [Indexed: 12/15/2022] Open
Abstract
Background and Aim Because ethanol consumption is commonly associated with a high cholesterol diet, we examined whether combined consumption of ethanol and high cholesterol increases liver injury and fibrosis. Methods Male C57BL/6J mice were fed diets containing: 1) 35% of calories from corn oil (CTR), 2) CTR plus 0.5% (w/v) cholesterol (Chol), 3) CTR plus ethanol (27% of calories) (EtOH), or 4) EtOH+Chol for 3 months. Results In mice fed Chol or EtOH alone, ALT increased to ~160 U/L, moderate hepatic steatosis occurred, and leukocyte infiltration, necrosis, and apoptosis increased modestly, but no observable fibrosis developed. By contrast in mice fed EtOH+Chol, ALT increased to ~270 U/L, steatosis was more extensive and mostly macrovesicular, and expression of proinflammatory molecules (HMGB-1, TLR4, TNFα, ICAM-1) and leukocyte infiltration increased substantially. Necrosis and apoptosis also increased. Trichrome staining and second harmonic generation microscopy revealed hepatic fibrosis. Fibrosis was mostly sinusoidal and/or perivenular, but in some mice bridging fibrosis occurred. Expression of smooth muscle α-actin and TGF-β1 increased slightly by Chol, moderately by EtOH, and markedly by EtOH+Chol. TGF-β pseudoreceptor BAMBI increased slightly by Chol, remained unchanged by EtOH and decreased by EtOH+Chol. MicroRNA-33a, which enhances TGF-β fibrotic effects, and phospho-Smad2/3, the down-stream signal of TGF-β, also increased more greatly by EtOH+Chol than Chol or EtOH. Metalloproteinase-2 and -9 were decreased only by EtOH+Chol. Conclusion High dietary cholesterol and chronic ethanol consumption synergistically increase liver injury, inflammation, and profibrotic responses and suppress antifibrotic responses, leading to severe steatohepatitis and early fibrosis in mice.
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Affiliation(s)
- Yasodha Krishnasamy
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Venkat K. Ramshesh
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Monika Gooz
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Rick G. Schnellmann
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina, United States of America
| | - John J. Lemasters
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Institute of Theoretical & Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
| | - Zhi Zhong
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail:
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Rehman H, Liu Q, Krishnasamy Y, Shi Z, Ramshesh VK, Haque K, Schnellmann RG, Murphy MP, Lemasters JJ, Rockey DC, Zhong Z. The mitochondria-targeted antioxidant MitoQ attenuates liver fibrosis in mice. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2016; 8:14-27. [PMID: 27186319 PMCID: PMC4859875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/15/2016] [Indexed: 06/05/2023]
Abstract
Oxidative stress plays an essential role in liver fibrosis. This study investigated whether MitoQ, an orally active mitochondrial antioxidant, decreases liver fibrosis. Mice were injected with corn oil or carbon tetrachloride (CCl4, 1:3 dilution in corn oil; 1 µl/g, ip) once every 3 days for up to 6 weeks. 4-Hydroxynonenal adducts increased markedly after CCl4 treatment, indicating oxidative stress. MitoQ attenuated oxidative stress after CCl4. Collagen 1α1 mRNA and hydroxyproline increased markedly after CCl4 treatment, indicating increased collagen formation and deposition. CCl4 caused overt pericentral fibrosis as revealed by both the sirius red staining and second harmonic generation microscopy. MitoQ blunted fibrosis after CCl4. Profibrotic transforming growth factor-β1 (TGF-β1) mRNA and expression of smooth muscle α-actin, an indicator of hepatic stellate cell (HSC) activation, increased markedly after CCl4 treatment. Smad 2/3, the major mediator of TGF-β fibrogenic effects, was also activated after CCl4 treatment. MitoQ blunted HSC activation, TGF-β expression, and Smad2/3 activation after CCl4 treatment. MitoQ also decreased necrosis, apoptosis and inflammation after CCl4 treatment. In cultured HSCs, MitoQ decreased oxidative stress, inhibited HSC activation, TGF-β1 expression, Smad2/3 activation, and extracellular signal-regulated protein kinase activation. Taken together, these data indicate that mitochondrial reactive oxygen species play an important role in liver fibrosis and that mitochondria-targeted antioxidants are promising potential therapies for prevention and treatment of liver fibrosis.
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Affiliation(s)
- Hasibur Rehman
- Department of Drug Discovery & Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
- Department of Biology, Faculty of Sciences, University of TabukSaudi Arabia
| | - Qinlong Liu
- Department of Drug Discovery & Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
- The Second Affiliated Hospital of Dalian Medical UniversityDalian, Liaoning Province, China
| | - Yasodha Krishnasamy
- Department of Drug Discovery & Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
| | - Zengdun Shi
- Department of Medicine, Medical University of South CarolinaCharleston, SC 29425, USA
| | - Venkat K Ramshesh
- Department of Drug Discovery & Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
| | - Khujista Haque
- Department of Drug Discovery & Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
| | - Rick G Schnellmann
- Department of Drug Discovery & Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
- Ralph H. Johnson VA Medical CenterCharleston, SC 29403, USA
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC BuildingCambridge CB2 0XY, U.K.
| | - John J Lemasters
- Department of Drug Discovery & Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
- Department of Biochemistry & Molecular Biology, Medical University of South CarolinaCharleston, SC 29425, USA
- Institute of Theoretical & Experimental Biophysics, Russian Academy of SciencesPushchino, Russian Federation
| | - Don C Rockey
- Department of Medicine, Medical University of South CarolinaCharleston, SC 29425, USA
| | - Zhi Zhong
- Department of Drug Discovery & Biomedical Sciences, Medical University of South CarolinaCharleston, SC 29425, USA
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Hu J, Ramshesh VK, McGill MR, Jaeschke H, Lemasters JJ. Low Dose Acetaminophen Induces Reversible Mitochondrial Dysfunction Associated with Transient c-Jun N-Terminal Kinase Activation in Mouse Liver. Toxicol Sci 2015; 150:204-15. [PMID: 26721299 DOI: 10.1093/toxsci/kfv319] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Acetaminophen (APAP) overdose causes hepatotoxicity involving mitochondrial dysfunction and c-jun N-terminal kinase (JNK) activation. Because the safe limit of APAP dosing is controversial, our aim was to evaluate the role of the mitochondrial permeability transition (MPT) and JNK in mitochondrial dysfunction after APAP dosing considered nontoxic by criteria of serum alanine aminotransferase (ALT) release and histological necrosis in vivo. C57BL/6 mice were given APAP with and without the MPT inhibitor, N-methyl-4-isoleucine cyclosporin (NIM811), or the JNK inhibitor, SP600125. Fat droplet formation, cell viability, and mitochondrial function in vivo were monitored by intravital multiphoton microscopy. Serum ALT, liver histology, total JNK, and activated phospho(p)JNK were also assessed. High APAP (300 mg/kg) caused ALT release, necrosis, irreversible mitochondrial dysfunction, and hepatocellular death. By contrast, lower APAP (150 mg/kg) caused reversible mitochondrial dysfunction and fat droplet formation in hepatocytes without ALT release or necrosis. Mitochondrial protein N-acetyl-p-benzoquinone imine adducts correlated with early JNK activation, but irreversible mitochondrial depolarization and necrosis at high dose were associated with sustained JNK activation and translocation to mitochondria. NIM811 prevented cell death and/or mitochondrial depolarization after both high and low dose APAP. After low dose, SP600125 decreased mitochondrial depolarization. In conclusion, low dose APAP produces reversible MPT-dependent mitochondrial dysfunction and steatosis in hepatocytes without causing ALT release or necrosis, whereas high dose leads to irreversible mitochondrial dysfunction and cell death associated with sustained JNK activation. Thus, nontoxic APAP has the potential to cause transient mitochondrial dysfunction that may synergize with other stresses to promote liver damage and steatosis.
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Affiliation(s)
- Jiangting Hu
- *Center for Cell Death, Injury & Regeneration; Departments of Drug Discovery & Biomedical Sciences and Biochemistry & Molecular Biology
| | - Venkat K Ramshesh
- *Center for Cell Death, Injury & Regeneration; Departments of Drug Discovery & Biomedical Sciences and Biochemistry & Molecular Biology; Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Mitchell R McGill
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160; and
| | - Hartmut Jaeschke
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160; and
| | - John J Lemasters
- *Center for Cell Death, Injury & Regeneration; Departments of Drug Discovery & Biomedical Sciences and Biochemistry & Molecular Biology; Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425; Institute of Theoretical & Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russian Federation
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Woolbright BL, Jaeschke H. Therapeutic targets for cholestatic liver injury. Expert Opin Ther Targets 2015; 20:463-75. [PMID: 26479335 DOI: 10.1517/14728222.2016.1103735] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Cholestasis is a reduction in bile flow that occurs during numerous pathologies. Blockage of the biliary tracts results in hepatic accumulation of bile acids or their conjugate bile salts. The molecular mechanisms behind liver injury associated with cholestasis are extensively studied, but not well understood. Multiple models of obstructive cholestasis result in a significant inflammatory infiltrate at the sites of necrosis that characterize the injury. AREAS COVERED This review will focus on direct bile acid toxicity during cholestasis, bile acid signaling processes and on the development and continuation of inflammation during cholestasis, with a focus on novel proposed molecular mediators of neutrophil recruitment. While significant progress has been made on these molecular mechanisms, a continued focus on how cholestasis and the innate immune system interact is necessary to discover targetable therapeutics that might protect the liver while leaving global immunity intact. EXPERT OPINION While bile acid toxicity likely occurs in humans and other mammals when toxic bile acids accumulate, persistent inflammation is likely responsible for continued liver injury during obstructive cholestasis. Targeting molecular mediators of inflammation may help prevent liver injury during acute cholestasis both in murine models and human patients.
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Affiliation(s)
- Benjamin L Woolbright
- a Department of Pharmacology , Toxicology & Therapeutics, University of Kansas Medical Center , 3901 Rainbow Blvd, MS 1018, Kansas City , KS , 66160 USA
| | - Hartmut Jaeschke
- a Department of Pharmacology , Toxicology & Therapeutics, University of Kansas Medical Center , 3901 Rainbow Blvd, MS 1018, Kansas City , KS , 66160 USA
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Pan N, Liu Z, He J, Li S, Lv X, Wang L, Liu Q. Comparison of Methods for the Reconstruction of the Hepatic Artery in Mouse Orthotopic Liver Transplantation. PLoS One 2015. [PMID: 26207367 PMCID: PMC4514862 DOI: 10.1371/journal.pone.0133030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Background The mouse model of arterialized orthotopic liver transplantation (AOLT) has played an important role in biomedical research. The available methods of sutured anastomosis for reconstruction of the hepatic artery are complicated, resulting in a high incidence of complications and failure. Therefore, we developed and evaluated a new model of AOLT in mice. Materials and methods Male inbred C57BL/6 mice were used in this study. A continuous suture approach was applied to connect the suprahepatic inferior vena cava (SHVC). The portal vein and infrahepatic inferior vena cava (IHVC) were connected according to the "two-cuff" method. The common bile duct was connected by a biliary stent. We used the stent (G3 group) or aortic trunk (G2 group) to reconstruct the hepatic artery. The patency of the hepatic artery was verified by transecting the artery near the graft after one week. The survival rate of the recipients and serum alanine aminotransferase (ALT) levels, hepatic pathologic alterations, apoptosis and necrosis were observed at one week postoperatively. Results The patency of the hepatic artery was verified in eight of ten mice in G3 and in six of ten mice in G2. The 7-day survival rate, extents of necrosis and apoptosis, and TGF-β levels were not significantly different among the three groups (P>0.05). However, the serum ALT levels and operation time were markedly lower in G3 compared with G2 or G1 (both P<0.05). Conclusions Reconstruction of the hepatic artery using a stent can be performed quickly with a high rate of patency. This model simplifies hepatic artery anastomosis and should be promoted in the field of biomedical research.
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Affiliation(s)
- Ning Pan
- Department of Anesthesiology, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning Province, China
| | - Zhenzhen Liu
- Department of General Surgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning Province, China
- Dalian Medical University, Dalian, Liaoning Province, China
| | - Jinjing He
- Department of General Surgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning Province, China
- Dalian Medical University, Dalian, Liaoning Province, China
| | - Song Li
- Department of General Surgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning Province, China
- Dalian Medical University, Dalian, Liaoning Province, China
| | - Xiangwei Lv
- Department of General Surgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning Province, China
- Dalian Medical University, Dalian, Liaoning Province, China
| | - Liming Wang
- Department of General Surgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning Province, China
| | - Qinlong Liu
- Department of General Surgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning Province, China
- * E-mail:
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18
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Yu T, Wang L, Lee H, O'Brien DK, Bronk SF, Gores GJ, Yoon Y. Decreasing mitochondrial fission prevents cholestatic liver injury. J Biol Chem 2014; 289:34074-88. [PMID: 25342755 DOI: 10.1074/jbc.m114.588616] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mitochondria frequently change their shape through fission and fusion in response to physiological stimuli as well as pathological insults. Disrupted mitochondrial morphology has been observed in cholestatic liver disease. However, the role of mitochondrial shape change in cholestasis is not defined. In this study, using in vitro and in vivo models of bile acid-induced liver injury, we investigated the contribution of mitochondrial morphology to the pathogenesis of cholestatic liver disease. We found that the toxic bile salt glycochenodeoxycholate (GCDC) rapidly fragmented mitochondria, both in primary mouse hepatocytes and in the bile transporter-expressing hepatic cell line McNtcp.24, leading to a significant increase in cell death. GCDC-induced mitochondrial fragmentation was associated with an increase in reactive oxygen species (ROS) levels. We found that preventing mitochondrial fragmentation in GCDC by inhibiting mitochondrial fission significantly decreased not only ROS levels but also cell death. We also induced cholestasis in mouse livers via common bile duct ligation. Using a transgenic mouse model inducibly expressing a dominant-negative fission mutant specifically in the liver, we demonstrated that decreasing mitochondrial fission substantially diminished ROS levels, liver injury, and fibrosis under cholestatic conditions. Taken together, our results provide new evidence that controlling mitochondrial fission is an effective strategy for ameliorating cholestatic liver injury.
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Affiliation(s)
- Tianzheng Yu
- From the Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912 and
| | - Li Wang
- From the Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912 and
| | - Hakjoo Lee
- From the Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912 and
| | - Dawn K O'Brien
- From the Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912 and
| | - Steven F Bronk
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota 55905
| | - Gregory J Gores
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota 55905
| | - Yisang Yoon
- From the Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912 and
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Babbey CM, Ryan JC, Gill EM, Ghabril MS, Burch CR, Paulman A, Dunn KW. Quantitative intravital microscopy of hepatic transport. INTRAVITAL 2014. [DOI: 10.4161/intv.21296] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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20
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Niimi K, Yasui T, Okada A, Hirose Y, Kubota Y, Umemoto Y, Kawai N, Tozawa K, Kohri K. Novel effect of the inhibitor of mitochondrial cyclophilin D activation, N-methyl-4-isoleucine cyclosporin, on renal calcium crystallization. Int J Urol 2014; 21:707-13. [PMID: 24661223 DOI: 10.1111/iju.12425] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 01/30/2014] [Indexed: 12/28/2022]
Abstract
OBJECTIVES To experimentally evaluate the clinical application of N-methyl-4-isoleucine cyclosporin, a novel selective inhibitor of cyclophilin D activation. METHODS In vitro, cultured renal tubular cells were exposed to calcium oxalate monohydrate crystals and treated with N-methyl-4-isoleucine cyclosporin. The mitochondrial membrane was stained with tetramethylrhodamine ethyl ester perchlorate and observed. In vivo, Sprague-Dawley rats were divided into four groups: a control group, an ethylene glycol group (administration of ethylene glycol to induce renal calcium crystallization), a N-methyl-4-isoleucine cyclosporin group (administration of N-methyl-4-isoleucine cyclosporin) and an ethylene glycol + N-methyl-4-isoleucine cyclosporin group (administration of ethylene glycol and N-methyl-4-isoleucine cyclosporin). Renal calcium crystallization was evaluated using Pizzolato staining. Oxidative stress was evaluated using superoxide dismutase and 8-hydroxy-deoxyguanosine. Mitochondria within renal tubular cells were observed by transmission electron microscopy. Cell apoptosis was evaluated using cleaved caspase-3. RESULTS In vitro, calcium oxalate monohydrate crystals induced depolarization of the mitochondrial membrane potential, which was remarkably prevented by N-methyl-4-isoleucine cyclosporin. In vivo, ethylene glycol administration induced renal calcium crystallization, oxidative stress, mitochondrial collapse and cell apoptosis in rats, which were significantly prevented by N-methyl-4-isoleucine cyclosporin. CONCLUSIONS Herein we first report a new treatment agent determining renal calcium crystallization through cyclophilin D activation.
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Affiliation(s)
- Kazuhiro Niimi
- Department of Nephro-urology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Sweeney ZK, Fu J, Wiedmann B. From chemical tools to clinical medicines: nonimmunosuppressive cyclophilin inhibitors derived from the cyclosporin and sanglifehrin scaffolds. J Med Chem 2014; 57:7145-59. [PMID: 24831536 DOI: 10.1021/jm500223x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The cyclophilins are widely expressed enzymes that catalyze the interconversion of the cis and trans peptide bonds of prolines. The immunosuppressive natural products cyclosporine A and sanglifehrin A inhibit the enzymatic activity of the cyclophilins. Chemical modification of both the cyclosporine and sanglifehrin scaffolds has produced many analogues that inhibit cyclophilins in vitro but have reduced immunosuppressive properties. Three nonimmunosuppressive cyclophilin inhibitors (alisporivir, SCY-635, and NIM811) have demonstrated clinical efficacy for the treatment of hepatitis C infection. Additional candidates are in various stages of preclinical development for the treatment of hepatitis C or myocardial reperfusion injury. Recent publications suggest that cyclophilin inhibitors may have utility for the treatment of diverse viral infections, inflammatory indications, and cancer. In this review, we document the structure-activity relationships of the nonimmunosuppressive cyclosporins and sanglifehrins in clinical and preclinical development. Aspects of the pharmacokinetic behavior and chemical biology of these drug candidates are also described.
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Affiliation(s)
- Zachary K Sweeney
- Novartis Institutes for BioMedical Research , 4560 Horton Street, Emeryville, California 94608, United States
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Acute ethanol causes hepatic mitochondrial depolarization in mice: role of ethanol metabolism. PLoS One 2014; 9:e91308. [PMID: 24618581 PMCID: PMC3950152 DOI: 10.1371/journal.pone.0091308] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 02/12/2014] [Indexed: 12/20/2022] Open
Abstract
Background/Aims An increase of ethanol metabolism and hepatic mitochondrial respiration occurs in vivo after a single binge of alcohol. Here, our aim was to determine how ethanol intake affects hepatic mitochondrial polarization status in vivo in relation to ethanol metabolism and steatosis. Methods Hepatic mitochondrial polarization, permeability transition (MPT), and reduce pyridine nucleotides, and steatosis in mice were monitored by intravital confocal/multiphoton microscopy of the fluorescence of rhodamine 123 (Rh123), calcein, NAD(P)H, and BODIPY493/503, respectively, after gavage with ethanol (1–6 g/kg). Results Mitochondria depolarized in an all-or-nothing fashion in individual hepatocytes as early as 1 h after alcohol. Depolarization was dose- and time-dependent, peaked after 6 to 12 h and maximally affected 94% of hepatocytes. This mitochondrial depolarization was not due to onset of the MPT. After 24 h, mitochondria of most hepatocytes recovered normal polarization and were indistinguishable from untreated after 7 days. Cell death monitored by propidium iodide staining, histology and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was low throughout. After alcohol, mitochondrial NAD(P)H autofluorescence increased and decreased, respectively, in hepatocytes with polarized and depolarized mitochondria. Ethanol also caused steatosis mainly in hepatocytes with depolarized mitochondria. Depolarization was linked to ethanol metabolism, since deficiency of alcohol dehydrogenase and cytochrome-P450 2E1 (CYP2E1), the major ethanol-metabolizing enzymes, decreased mitochondrial depolarization by ∼70% and ∼20%, respectively. Activation of aldehyde dehydrogenase decreased depolarization, whereas inhibition of aldehyde dehydrogenase enhanced depolarization. Activation of aldehyde dehydrogenase also markedly decreased steatosis. Conclusions Acute ethanol causes reversible hepatic mitochondrial depolarization in vivo that may contribute to steatosis and increased mitochondrial respiration. Onset of this mitochondrial depolarization is linked, at least in part, to metabolism of ethanol to acetaldehyde.
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Rehman H, Krishnasamy Y, Haque K, Thurman RG, Lemasters JJ, Schnellmann RG, Zhong Z. Green tea polyphenols stimulate mitochondrial biogenesis and improve renal function after chronic cyclosporin a treatment in rats. PLoS One 2013; 8:e65029. [PMID: 23755172 PMCID: PMC3670924 DOI: 10.1371/journal.pone.0065029] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/21/2013] [Indexed: 11/30/2022] Open
Abstract
Our previous studies showed that an extract from Camellia sinenesis (green tea), which contains several polyphenols, attenuates nephrotoxicity caused by cyclosporine A (CsA). Since polyphenols are stimulators of mitochondrial biogenesis (MB), this study investigated whether stimulation of MB plays a role in green tea polyphenol protection against CsA renal toxicity. Rats were fed a powdered diet containing green tea polyphenolic extract (0.1%) starting 3 days prior to CsA treatment (25 mg/kg, i.g. daily for 3 weeks). CsA alone decreased renal nuclear DNA-encoded oxidative phosphorylation (OXPHOS) protein ATP synthase-β (AS-β) by 42%, mitochondrial DNA (mtDNA)-encoded OXPHOS protein NADH dehydrogenase-3 (ND3) by 87% and their associated mRNAs. Mitochondrial DNA copy number was also decreased by 78% by CsA. Immunohistochemical analysis showed decreased cytochrome c oxidase subunit IV (COX-IV), an OXPHOS protein, in tubular cells. Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α, the master regulator of MB, and mitochondrial transcription factor-A (Tfam), the transcription factor that regulates mtDNA replication and transcription, were 42% and 90% lower, respectively, in the kidneys of CsA-treated than in untreated rats. These results indicate suppression of MB by chronic CsA treatment. Green tea polyphenols alone and following CsA increased AS-β, ND3, COX-IV, mtDNA copy number, PGC-1α mRNA and protein, decreased acetylated PGC-1α, and increased Tfam mRNA and protein. In association with suppressed MB, CsA increased serum creatinine, caused loss of brush border and dilatation of proximal tubules, tubular atrophy, vacuolization, apoptosis, calcification, and increased neutrophil gelatinase-associated lipocalin expression, leukocyte infiltration, and renal fibrosis. Green tea polyphenols markedly attenuated CsA-induced renal injury and improved renal function. Together, these results demonstrate that green tea polyphenols attenuate CsA-induced kidney injury, at least in part, through the stimulation of MB.
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Affiliation(s)
- Hasibur Rehman
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Yasodha Krishnasamy
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Khujista Haque
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Ronald G. Thurman
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - John J. Lemasters
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Rick G. Schnellmann
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina, United States of America
| | - Zhi Zhong
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina, United States of America
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Liu Q, Rehman H, Krishnasamy Y, Haque K, Schnellmann R, Lemasters J, Zhong Z. Amphiregulin stimulates liver regeneration after small-for-size mouse liver transplantation. Am J Transplant 2012; 12:2052-61. [PMID: 22694592 PMCID: PMC3409348 DOI: 10.1111/j.1600-6143.2012.04069.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This study investigated whether amphiregulin (AR), a ligand of the epidermal growth factor receptor (EGFR), improves liver regeneration after small-for-size liver transplantation. Livers of male C57BL/6 mice were reduced to ~50% and ~30% of original sizes and transplanted. After transplantation, AR and AR mRNA increased in 50% but not in 30% grafts. 5-Bromodeoxyuridine (BrdU) labeling, proliferating cell nuclear antigen (PCNA) expression and mitotic index increased substantially in 50% but not 30% grafts. Hyperbilirubinemia and hypoalbuminemia occurred and survival decreased after transplantation of 30% but not 50% grafts. AR neutralizing antibody blunted regeneration in 50% grafts whereas AR injection (5 μg/mouse, iv) stimulated liver regeneration, improved liver function and increased survival after transplantation of 30% grafts. Phosphorylation of EGFR and its downstream signaling molecules Akt, mTOR, p70S6K, ERK and JNK increased markedly in 50% but not 30% grafts. AR stimulated EGFR phosphorylation and its downstream signaling pathways. EGFR inhibitor PD153035 suppressed regeneration of 50% grafts and largely abrogated stimulation of regeneration of 30% grafts by AR. AR also increased cyclin D1 and cyclin E expression in 30% grafts. Together, liver regeneration is suppressed in small-for-size grafts, as least in part, due to decreased AR formation. AR supplementation could be a promising therapy to stimulate regeneration of partial liver grafts.
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Affiliation(s)
- Q. Liu
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425,Department of General Surgery, the Second Affiliated Hospital of Dalian Medical University, Dalian, China
| | - H. Rehman
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Y. Krishnasamy
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - K. Haque
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - R.G. Schnellmann
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425,Ralph H. Johnson VA Medical Center, Charleston, SC 29403
| | - J.J. Lemasters
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425,Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, SC 29425,Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425
| | - Z. Zhong
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425,Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425
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Liu Q, Rehman H, Shi Y, Krishnasamy Y, Lemasters JJ, Smith CD, Zhong Z. Inhibition of sphingosine kinase-2 suppresses inflammation and attenuates graft injury after liver transplantation in rats. PLoS One 2012; 7:e41834. [PMID: 22848628 PMCID: PMC3405047 DOI: 10.1371/journal.pone.0041834] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 06/25/2012] [Indexed: 11/28/2022] Open
Abstract
Inflammation mediates/promotes graft injury after liver transplantation (LT). This study investigated the roles of sphingosine kinase-2 (SK2) in inflammation after LT. Liver grafts were stored in UW solution with and without ABC294640 (100 µM), a selective inhibitor of SK2, before implantation. Hepatic sphingosine-1-phosphate (S1P) levels increased ∼4-fold after LT, which was blunted by 40% by ABC294640. Hepatic toll-like receptor-4 (TLR4) expression and nuclear factor-κB (NF-κB) p65 subunit phosphorylation elevated substantially after transplantation. The pro-inflammatory cytokines/chemokines tumor necrosis factor-α, interleukin-1β and C-X-C motif chemokine 10 mRNAs increased 5.9-fold, 6.1-fold and 16-fold, respectively following transplantation, while intrahepatic adhesion molecule-1 increased 5.7-fold and monocytes/macrophage and neutrophil infiltration and expansion of residential macrophage population increased 7.8-13.4 fold, indicating enhanced inflammation. CD4+ T cell infiltration and interferon-γ production also increased. ABC294640 blunted TLR4 expression by 60%, NF-κB activation by 84%, proinflammatory cytokine/chemokine production by 45-72%, adhesion molecule expression by 54% and infiltration of monocytes/macrophages and neutrophils by 62-67%. ABC294640 also largely blocked CD4+ T cell infiltration and interferon-γ production. Focal necrosis and apoptosis occurred after transplantation with serum alanine aminotransferase (ALT) reaching ∼6000 U/L and serum total bilirubin elevating to ∼1.5 mg/dL. Inhibition of SK2 by ABC294640 blunted necrosis by 57%, apoptosis by 74%, ALT release by ∼68%, and hyperbilirubinemia by 74%. Most importantly, ABC294640 also increased survival from ∼25% to ∼85%. In conclusion, SK2 plays an important role in hepatic inflammation responses and graft injury after cold storage/transplantation and represents a new therapeutic target for liver graft failure.
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Affiliation(s)
- Qinlong Liu
- Departments of Pharmaceutical & Biomedical Sciences and Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Hasibur Rehman
- Departments of Pharmaceutical & Biomedical Sciences and Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Yanjun Shi
- Departments of Pharmaceutical & Biomedical Sciences and Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Yasodha Krishnasamy
- Departments of Pharmaceutical & Biomedical Sciences and Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - John J. Lemasters
- Departments of Pharmaceutical & Biomedical Sciences and Medical University of South Carolina, Charleston, South Carolina, United States of America
- Biochemistry & Molecular Biology, and Medical University of South Carolina, Charleston, South Carolina, United States of America
- Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Charles D. Smith
- Departments of Pharmaceutical & Biomedical Sciences and Medical University of South Carolina, Charleston, South Carolina, United States of America
- Apogee Biotechnology Corporation, Hummelstown, Pennsylvania, United States of America
| | - Zhi Zhong
- Departments of Pharmaceutical & Biomedical Sciences and Medical University of South Carolina, Charleston, South Carolina, United States of America
- Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, United States of America
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Small-for-Size Liver Transplantation Increases Pulmonary Injury in Rats: Prevention by NIM811. HPB SURGERY : A WORLD JOURNAL OF HEPATIC, PANCREATIC AND BILIARY SURGERY 2012; 2012:270372. [PMID: 22675237 PMCID: PMC3364580 DOI: 10.1155/2012/270372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 03/09/2012] [Indexed: 01/20/2023]
Abstract
Pulmonary complications after liver transplantation (LT) often cause mortality. This study investigated whether small-for-size LT increases acute pulmonary injury and whether NIM811 which improves small-for-size liver graft survival attenuates LT-associated lung injury. Rat livers were reduced to 50% of original size, stored in UW-solution with and without NIM811 (5 μM) for 6 h, and implanted into recipients of the same or about twice the donor weight, resulting in half-size (HSG) and quarter-size grafts (QSG), respectively. Liver injury increased and regeneration was suppressed after QSG transplantation as expected. NIM811 blunted these alterations >75%. Pulmonary histological alterations were minimal at 5–18 h after LT. At 38 h, neutrophils and monocytes/macrophage infiltration, alveolar space exudation, alveolar septal thickening, oxidative/nitrosative protein adduct formation, and alveolar epithelial cell/capillary endothelial apoptosis became overt in the lungs of QSG recipients, but these alterations were mild in full-size and HSG recipients. Liver pretreatment with NIM811 markedly decreased pulmonary injury in QSG recipients. Hepatic TNFα and IL-1β mRNAs and pulmonary ICAM-1 expression were markedly higher after QSG transplantation, which were all decreased by NIM811. Together, dysfunctional small-for-size grafts produce toxic cytokines, leading to lung inflammation and injury. NIM811 decreased toxic cytokine formation, thus attenuating pulmonary injury after small-for-size LT.
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27
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Niimi K, Yasui T, Hirose M, Hamamoto S, Itoh Y, Okada A, Kubota Y, Kojima Y, Tozawa K, Sasaki S, Hayashi Y, Kohri K. Mitochondrial permeability transition pore opening induces the initial process of renal calcium crystallization. Free Radic Biol Med 2012; 52:1207-17. [PMID: 22285391 DOI: 10.1016/j.freeradbiomed.2012.01.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 12/27/2011] [Accepted: 01/09/2012] [Indexed: 12/17/2022]
Abstract
Renal tubular cell injury induced by oxidative stress via mitochondrial collapse is thought to be the initial process of renal calcium crystallization. Mitochondrial collapse is generally caused by mitochondrial permeability transition pore (mPTP) opening, which can be blocked by cyclosporine A (CsA). Definitive evidence for the involvement of mPTP opening in the initial process of renal calcium crystallization, however, is lacking. In this study, we examined the physiological role of mPTP opening in renal calcium crystallization in vitro and in vivo. In the in vitro study, cultured renal tubular cells were exposed to calcium oxalate monohydrate (COM) crystals and treated with CsA (2 μM). COM crystals induced depolarization of the mitochondrial membrane potential and generated oxidative stress as evaluated by Cu-Zn SOD and 4-HNE. Furthermore, the expression of cytochrome c and cleaved caspase 3 was increased and these effects were prevented by CsA. In the in vivo study, Sprague-Dawley rats were administered 1% ethylene glycol (EG) to generate a rat kidney stone model and then treated with CsA (2.5, 5.0, and 10.0 mg/kg/day) for 14 days. EG administration induced renal calcium crystallization, which was prevented by CsA. Mitochondrial collapse was demonstrated by transmission electron microscopy, and oxidative stress was evaluated by measuring Cu-Zn SOD, MDA, and 8-OHdG generated by EG administration, all of which were prevented by CsA. Collectively, our results provide compelling evidence for a role of mPTP opening and its associated mitochondrial collapse, oxidative stress, and activation of the apoptotic pathway in the initial process of renal calcium crystallization.
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Affiliation(s)
- Kazuhiro Niimi
- Department of Nephro-urology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
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Jaeschke H, McGill MR, Ramachandran A. Oxidant stress, mitochondria, and cell death mechanisms in drug-induced liver injury: lessons learned from acetaminophen hepatotoxicity. Drug Metab Rev 2012; 44:88-106. [PMID: 22229890 DOI: 10.3109/03602532.2011.602688] [Citation(s) in RCA: 645] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hepatotoxicity is a serious problem during drug development and for the use of many established drugs. For example, acetaminophen overdose is currently the most frequent cause of acute liver failure in the United States and Great Britain. Evaluation of the mechanisms of drug-induced liver injury indicates that mitochondria are critical targets for drug toxicity, either directly or indirectly through the formation of reactive metabolites. The consequence of these modifications is generally a mitochondrial oxidant stress and peroxynitrite formation, which leads to structural alterations of proteins and mitochondrial DNA and, eventually, to the opening of mitochondrial membrane permeability transition (MPT) pores. MPT pore formation results in a collapse of mitochondrial membrane potential and cessation of adenosine triphosphate synthesis. In addition, the release of intermembrane proteins, such as apoptosis-inducing factor and endonuclease G, and their translocation to the nucleus, leads to nuclear DNA fragmentation. Together, these events trigger necrotic cell death. Alternatively, the release of cytochrome c and other proapoptotic factors from mitochondria can promote caspase activation and apoptotic cell death. Drug toxicity can also induce an inflammatory response with the formation of reactive oxygen species by Kupffer cells and neutrophils. If not properly detoxified, these extracellularly generated oxidants can diffuse into hepatocytes and trigger mitochondrial dysfunction and oxidant stress, which then induces MPT and necrotic cell death. This review addresses the formation of oxidants and the defense mechanisms available for cells and applies this knowledge to better understand mechanisms of drug hepatotoxicity, especially acetaminophen-induced liver injury.
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Affiliation(s)
- Hartmut Jaeschke
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, 66160, USA.
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29
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Shi Y, Rehman H, Ramshesh VK, Schwartz J, Liu Q, Krishnasamy Y, Zhang X, Lemasters JJ, Smith CD, Zhong Z. Sphingosine kinase-2 inhibition improves mitochondrial function and survival after hepatic ischemia-reperfusion. J Hepatol 2012; 56:137-45. [PMID: 21756852 PMCID: PMC3220779 DOI: 10.1016/j.jhep.2011.05.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 04/29/2011] [Accepted: 05/02/2011] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS The mitochondrial permeability transition (MPT) and inflammation play important roles in liver injury caused by ischemia-reperfusion (IR). This study investigated the roles of sphingosine kinase-2 (SK2) in mitochondrial dysfunction and inflammation after hepatic IR. METHODS Mice were gavaged with vehicle or ABC294640 (50 mg/kg), a selective inhibitor of SK2, 1 h before surgery and subjected to 1 h-warm ischemia to ~70% of the liver followed by reperfusion. RESULTS Following IR, hepatic SK2 mRNA and sphingosine-1-phosphate (S1P) levels increased ~25- and 3-fold, respectively. SK2 inhibition blunted S1P production and liver injury by 54-91%, and increased mouse survival from 28% to 100%. At 2 h after reperfusion, mitochondrial depolarization was observed in 74% of viable hepatocytes, and mitochondrial voids excluding calcein disappeared, indicating MPT onset in vivo. SK2 inhibition decreased mitochondrial depolarization and prevented MPT onset. Inducible nitric oxide synthase, phosphorylated NFκB-p65, TNFα mRNA, and neutrophil infiltration, all increased markedly after hepatic IR, and these increases were blunted by SK2 inhibition. In cultured hepatocytes, anoxia/re-oxygenation resulted in increases of SK2 mRNA, S1P levels, and cell death. SK2 siRNA and ABC294640 each substantially decreased S1P production and cell death in cultured hepatocytes. CONCLUSIONS SK2 plays an important role in mitochondrial dysfunction, inflammation responses, hepatocyte death, and survival after hepatic IR and represents a new target for the treatment of IR injury.
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Affiliation(s)
- Yanjun Shi
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Hasibur Rehman
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Venkat K. Ramshesh
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425,Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, SC 29425
| | - Justin Schwartz
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Qinlong Liu
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Yasodha Krishnasamy
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Xun Zhang
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - John J. Lemasters
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425,Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, SC 29425,Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425
| | - Charles D. Smith
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425,Apogee Biotechnology Corporation, Hummelstown, PA 17036
| | - Zhi Zhong
- Department of Pharmaceutical & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425
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Thorling CA, Liu X, Burczynski FJ, Fletcher LM, Gobe GC, Roberts MS. Multiphoton microscopy can visualize zonal damage and decreased cellular metabolic activity in hepatic ischemia-reperfusion injury in rats. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:116011. [PMID: 22112116 DOI: 10.1117/1.3647597] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Ischemia-reperfusion (I/R) injury is a common occurrence in liver surgery. In orthotopic transplantation, the donor liver is exposed to periods of ischemia and when oxygenated blood is reintroduced to the liver, oxidative stress may develop and lead to graft failure. The aim of this project was to investigate whether noninvasive multiphoton and fluorescence lifetime imaging microscopy, without external markers, were useful in detecting early liver damage caused by I/R injury. Localized hepatic ischemia was induced in rats for 1 h followed by 4 h reperfusion. Multiphoton and fluorescence lifetime imaging microscopy was conducted prior to ischemia and up to 4 h of reperfusion and compared to morphological and biochemical assessment of liver damage. Liver function was significantly impaired at 2 and 4 h of reperfusion. Multiphoton microscopy detected liver damage at 1 h of reperfusion, manifested by vacuolated cells and heterogeneous spread of damage over the liver. The damage was mainly localized in the midzonal region of the liver acinus. In addition, fluorescence lifetime imaging showed a decrease in cellular metabolic activity. Multiphoton and fluorescence lifetime imaging microscopy detected evidence of early I/R injury both structurally and functionally. This provides a simple noninvasive technique useful for following progressive liver injury without external markers.
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Affiliation(s)
- Camilla A Thorling
- The University of Queensland, School of Medicine, Woolloongabba, Queensland, 4102, Australia
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Li S, Tang Z, Yu H, Li W, Jiang Y, Wang Y, An W. Administration of naked plasmid encoding hepatic stimulator substance by hydrodynamic tail vein injection protects mice from hepatic failure by suppressing the mitochondrial permeability transition. J Pharmacol Exp Ther 2011; 338:750-7. [PMID: 21613410 DOI: 10.1124/jpet.111.181305] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Acute liver failure is a devastating illness of various causes with considerable mortality. Hepatic stimulator substance (HSS) has been suggested for use as a protective agent against acute hepatic injury induced by chemical poisons because it has a variety of biological activities. However, the mechanism whereby HSS protects against hepatotoxins is poorly understood. In this study, we established a hepatic gene transfer system via hydrodynamic tail vein injection to deliver a naked plasmid containing the human HSS gene (hHSS) and analyzed HSS-mediated protection of the liver during fulminant hepatic failure (FHF) induced by D-galactosamine (D-gal) and lipopolysaccharide (LPS). The results showed that the reporter gene, enhanced green fluorescent protein, was efficiently expressed in the liver of BALB/c mice. Hydrodynamic-based transfection of hHSS yielded a 70% survival rate compared with 36.7% for the control group at 24 h after D-gal/LPS treatment. In addition, hHSS expression preserved liver morphology and function. It is noteworthy that hHSS hydrodynamic-based transfer ameliorated indices of the mitochondrial permeability transition (MPT) resulting from the toxic effects of d-gal/LPS on the liver such as mitochondrial swelling, mitochondrial transmembrane potential disruption, and cytochrome c translocation. Furthermore, mitochondrial morphology and ATP levels were maintained in hHSS-administered mice. HSS-mediated protection was similar to that observed with the MPT inhibitor N-methyl-4-isoleucine-cyclosporin (NIM811), indicating a possible role for HSS in the regulation of MPT. In conclusion, a single dose of hHSS plasmid protected mice from FHF, and this hepatoprotective effect seemed to correlate with the inhibition of MPT.
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Affiliation(s)
- Shenglan Li
- Department of Cell Biology and Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, China
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32
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NIM811 prevents mitochondrial dysfunction, attenuates liver injury, and stimulates liver regeneration after massive hepatectomy. Transplantation 2011; 91:406-12. [PMID: 21131897 DOI: 10.1097/tp.0b013e318204bdb2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Massive hepatectomy (MHX) leads to failure of remnant livers. Excessive metabolic burden in remnant livers may cause mitochondrial dysfunction. This study investigated whether blockade of the mitochondrial permeability transition (MPT) with N-methyl-4-isoleucine cyclosporine (NIM811) improves the outcome of MHX. METHODS Mice were gavaged with NIM811 (10 mg/kg before surgery and 5 mg/kg daily afterward) and underwent sham-operation or approximately 90% partial hepatectomy. RESULTS Serum alanine aminotransferase, necrosis, and apoptosis increased, respectively, to approximately 1200 U/L, 6.1%, and 7% after MHX. NIM811 decreased peak alanine aminotransferase release, necrosis, and apoptosis by 70%, 100%, and 42%, respectively. 5-Bromo-2'-deoxyuridine incorporation, proliferating cell nuclear antigen expression, and the remnant liver weights were all increased significantly by NIM811 treatment, indicating improved liver regeneration. NIM811 also blunted hyperbilirubinemia by 54%, increased serum albumin by 51%, and improved survival from 6% to 40% after MHX. Hepatic mitochondrial depolarization, cell death, and MPT were detected by intravital confocal/multiphoton microscopy of rhodamine 123, propidium iodide, and calcein. Mitochondrial depolarization occurred in many viable hepatocytes (13 cells/high-power field), and nonviable hepatocytes increased slightly to approximately 1 cell/high-power field at 3 hr after MHX. Entry of calcein into mitochondria after MHX indicated MPT onset. Importantly, NIM811 decreased mitochondria depolarization by more than 60%, blocked MPT onset, and prevented cell death. Decreases of hepatic ATP, mitochondrial cytochrome c release, and caspase-3 activation after MHX were also partially blocked by NIM811. CONCLUSIONS NIM811 minimized liver injury and improved liver regeneration after MHX, at least in part, by preventing MPT onset and subsequent compromised energy supply and proapoptotic cytochrome c release.
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Wang H, Zhang Y, Wang T, You H, Jia J. N-methyl-4-isoleucine cyclosporine attenuates CCl -induced liver fibrosis in rats by interacting with cyclophilin B and D. J Gastroenterol Hepatol 2011; 26:558-67. [PMID: 21332552 DOI: 10.1111/j.1440-1746.2010.06406.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIM N-methyl-4-isoleucine cyclosporine (NIM811), a new analogue of cyclosporine A, can inhibit collagen deposition in vitro and reduce liver necrosis in a bile-duct-ligation animal model. However, whether NIM811 effects on CCl(4) -induced rat liver fibrosis, and the related mechanism has not been determined. METHODS A liver fibrosis model was induced in Wistar rats using CCl(4) for 6 weeks. Meanwhile, two different doses of NIM811 (low-dose 10 mg/kg and high-dose 20 mg/kg) were given to the CCl(4) -treated rats. Liver fibrosis was then evaluated according to histopathological scoring and liver hydroxyproline content. Serum alanine aminotransferase, aspartate aminotransferase and albumin levels, expression of matrix metalloproteinase-13, tissue inhibitor of metalloproteinase-1, α-smooth muscle actin and cyclophilin B and D in liver tissue were determined. Cyclophilin B and D were also studied in an hepatic stellate cell line. RESULTS Hydroxyproline content was decreased in both NIM811 groups compared with the model (P < 0.05). Liver necrosis and fibrosis were also attenuated in the NIM811 groups. NIM811 suppressed the expression of tissue inhibitor of metalloproteinase-1, transforming growth factor beta mRNA and α-smooth muscle actin protein in liver tissue. Expression of cyclophilin B in the fibrosis model was increased compared with the normal group (P < 0.05), and was decreased significantly in the low-dose NIM811 treatment group (P < 0.05), which indicated that cyclophilin B might have a profibrotic effect. In vitro studies revealed that cyclophilin B and/or D knockout were associated with collagen inhibition. CONCLUSIONS NIM811 attenuates liver fibrosis in a CCl(4)-induced rat liver fibrosis model, which may be related to binding with cyclophilin B and D.
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Affiliation(s)
- Hui Wang
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
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34
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Safety, pharmacokinetics, and antiviral activity of the cyclophilin inhibitor NIM811 alone or in combination with pegylated interferon in HCV-infected patients receiving 14 days of therapy. Antiviral Res 2011; 89:238-45. [PMID: 21255610 DOI: 10.1016/j.antiviral.2011.01.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 12/09/2010] [Accepted: 01/11/2011] [Indexed: 12/13/2022]
Abstract
BACKGROUND Cyclophilin inhibitors have shown activity against a variety of viruses, including HCV. NIM811, a novel, non-immunosuppressive cyclophilin inhibitor was studied in ascending doses in a randomized, double-blind, placebo-controlled 14-day trial in genotype 1 HCV patients. Doses of 10 up to 600 mg were given orally once or twice daily as monotherapy (9:3 randomization of NIM811:placebo). 600 mg or placebo bid for 14 days was then co-administered with pegylated interferon alpha (PEG-IFN-α) administered on days 1 and 8 to genotype 1 relapsers. RESULTS NIM811 was well tolerated at all doses. Although lack of antiviral effect was noted in the monotherapy arms, liver transaminase normalization occurred at doses over 75 mg. Mild, clinically non-significant elevations of bilirubin, and significant declines in platelet numbers were observed in the 400 and 600 mg bid groups. In the combination group, the mean HCV RNA decline was 2.85 log, compared to a 0.56 log in the PEG-IFN alone arm. The mean ALT (alanine transaminase) declined significantly by day 14 in the combination, but was unchanged in the PEG-IFN alone group. In the combination therapy group, the mean platelets were 203×10(9)/L at baseline and fell to 105×10(9)/L by day 14; for patients treated with PEG-IFN the values were 177×10(9)/L and 139×10(9)/L. There was a significant increase in bilirubin, although this did not reach clinically concerning levels. There were no severe or serious adverse events. The pharmacokinetics in both monotherapy and combination arms were dose linear and not affected by PEG-INF. CONCLUSION NIM811 monotherapy resulted in a normalization of liver transaminases in the absence of significant virological response. The combination of NIM811 and pegylated interferon alpha showed significant antiviral activity compared to interferon alone in genotype 1 HCV relapsers. The use of oral cyclophilin inhibitors as part of a combination regime for treatment of hepatitis C, especially to deter resistance, holds promise.
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A pore way to die: the role of mitochondria in reperfusion injury and cardioprotection. Biochem Soc Trans 2010; 38:841-60. [DOI: 10.1042/bst0380841] [Citation(s) in RCA: 238] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In addition to their normal physiological role in ATP production and metabolism, mitochondria exhibit a dark side mediated by the opening of a non-specific pore in the inner mitochondrial membrane. This mitochondrial permeability transition pore (MPTP) causes the mitochondria to breakdown rather than synthesize ATP and, if unrestrained, leads to necrotic cell death. The MPTP is opened in response to Ca2+ overload, especially when accompanied by oxidative stress, elevated phosphate concentration and adenine nucleotide depletion. These conditions are experienced by the heart and brain subjected to reperfusion after a period of ischaemia as may occur during treatment of a myocardial infarction or stroke and during heart surgery. In the present article, I review the properties, regulation and molecular composition of the MPTP. The evidence for the roles of CyP-D (cyclophilin D), the adenine nucleotide translocase and the phosphate carrier are summarized and other potential interactions with outer mitochondrial membrane proteins are discussed. I then review the evidence that MPTP opening mediates cardiac reperfusion injury and that MPTP inhibition is cardioprotective. Inhibition may involve direct pharmacological targeting of the MPTP, such as with cyclosporin A that binds to CyP-D, or indirect inhibition of MPTP opening such as with preconditioning protocols. These invoke complex signalling pathways to reduce oxidative stress and Ca2+ load. MPTP inhibition also protects against congestive heart failure in hypertensive animal models. Thus the MPTP is a very promising pharmacological target for clinical practice, especially once more specific drugs are developed.
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