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Yin N, Zhang W, Wei R, Yang Q, He F, Guo L, Feng M. Liposome cocktail activator modulates hepatocytes and remodels the microenvironment to mitigate acute liver failure. Asian J Pharm Sci 2022; 17:867-879. [PMID: 36600898 PMCID: PMC9800940 DOI: 10.1016/j.ajps.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/09/2022] [Accepted: 10/04/2022] [Indexed: 01/07/2023] Open
Abstract
Acute liver failure (ALF) is a mortal and critical hepatic disease, in which oxidative stress, inflammation storm and hepatocyte death are crucial in the pathogenesis. Hence, in contrast to the control of a single link, a combination therapy targeting multiple pathogenic links of the disease will be a favorable means to control the progression of the disease. In this study, we constructed dimethyl itaconate-loaded liposomes modified with dodecyl gallate as a cocktail activator to investigate its functional role in acetaminophen (APAP)-induced ALF. Our results demonstrated that the cocktail activator acted on hepatocytes and triggered cocktail efficacy, thereby simultaneously attenuating APAP-induced hepatocyte damage and remodeling the damage microenvironment. The cocktail activator could effectively scavenge reactive oxygen species, inhibit excessive inflammatory responses and reduce cell death in impaired hepatocytes for detoxification. More importantly, the cocktail activator could remodel the damage microenvironment, thus further promoting hepatocyte expansion and specifically switching macrophages from the M1 to M2 phenotype for a favorable liver regeneration of ALF. Furthermore, in APAP-induced ALF mouse model, the cocktail activator improved liver function, alleviated histopathological damage and increased survival rate. In summary, these findings indicate that the cocktail activator may provide a promising therapeutic approach for ALF treatment as a nanomedicine.
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Affiliation(s)
- Na Yin
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Wenjun Zhang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Runxiu Wei
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Qiang Yang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Fengming He
- School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China
| | - Ling Guo
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
- School of Pharmaceutical Sciences, Hainan University, Haikou 570228, China
- Corresponding authors.
| | - Min Feng
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
- Corresponding authors.
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Park ES, Dezhbord M, Lee AR, Park BB, Kim KH. Dysregulation of Liver Regeneration by Hepatitis B Virus Infection: Impact on Development of Hepatocellular Carcinoma. Cancers (Basel) 2022; 14:cancers14153566. [PMID: 35892823 PMCID: PMC9329784 DOI: 10.3390/cancers14153566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 02/04/2023] Open
Abstract
The liver is unique in its ability to regenerate in response to damage. The complex process of liver regeneration consists of multiple interactive pathways. About 2 billion people worldwide have been infected with hepatitis B virus (HBV), and HBV causes 686,000 deaths each year due to its complications. Long-term infection with HBV, which causes chronic inflammation, leads to serious liver-related diseases, including cirrhosis and hepatocellular carcinoma. HBV infection has been reported to interfere with the critical mechanisms required for liver regeneration. In this review, the studies on liver tissue characteristics and liver regeneration mechanisms are summarized. Moreover, the inhibitory mechanisms of HBV infection in liver regeneration are investigated. Finally, the association between interrupted liver regeneration and hepatocarcinogenesis, which are both triggered by HBV infection, is outlined. Understanding the fundamental and complex liver regeneration process is expected to provide significant therapeutic advantages for HBV-associated hepatocellular carcinoma.
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Affiliation(s)
- Eun-Sook Park
- Institute of Biomedical Science and Technology, School of Medicine, Konkuk University, Seoul 05029, Korea; (E.-S.P.); (B.B.P.)
| | - Mehrangiz Dezhbord
- Department of Precision Medicine, School of Medicine, Sungkyunkwan University, Suwon 16419, Korea; (M.D.); (A.R.L.)
| | - Ah Ram Lee
- Department of Precision Medicine, School of Medicine, Sungkyunkwan University, Suwon 16419, Korea; (M.D.); (A.R.L.)
| | - Bo Bae Park
- Institute of Biomedical Science and Technology, School of Medicine, Konkuk University, Seoul 05029, Korea; (E.-S.P.); (B.B.P.)
| | - Kyun-Hwan Kim
- Department of Precision Medicine, School of Medicine, Sungkyunkwan University, Suwon 16419, Korea; (M.D.); (A.R.L.)
- Correspondence: ; Tel.: +82-31-299-6126
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Alleviation of CCCP-induced mitochondrial injury by augmenter of liver regeneration via the PINK1/Parkin pathway-dependent mitophagy. Exp Cell Res 2021; 409:112866. [PMID: 34655600 DOI: 10.1016/j.yexcr.2021.112866] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 11/21/2022]
Abstract
The occurrence of liver diseases is attributed to mitochondrial damage. Mitophagy selectively removes dysfunctional mitochondria, thereby preserving mitochondrial function. Augmenter of liver regeneration (ALR) protects the mitochondria from injury. However, whether ALR protection is associated with mitophagy remains unclear. In this study, mitochondrial damage was induced by carbonyl cyanide 3-chlorophenylhydrazone (CCCP), and long-form ALR (lfRNA)-mediated protection against this damage was investigated. Treatment of HepG2 cells with CCCP elevated the level of intracellular ROS, inhibited ATP production, and increased the mitochondrial membrane potential and cell apoptotic rate. However, in lfALR-transfected cells, CCCP-induced cell injury was clearly alleviated, the apoptosis and ROS levels clearly declined, and the ATP production was significantly enhanced as compared with that in vector-Tx cells. Furthermore, lfALR overexpression promoted autophagy and mitophagy via a PINK1/Parkin-dependent pathway, whereas knockdown of ALR suppressed mitophagy. In lfALR-transfected cells, the phosphorylation of AKT was decreased, thus, downregulating the phosphorylation of the transcription factor FOXO3a at Ser315. In contrast, the phosphorylation of AMPK was enhanced, thereby upregulating the phosphorylation of FOXO3a at Ser413. Consequently, FOXO3a's nuclear translocation and binding to the promoter region of PINK1 was enhanced, and the accumulation of PINK1/Parkin in mitochondria increased. Meanwhile, short-form ALR (sfALR) also increased PINK1 expression through FOXO3a with the similar pathway to lfALR. In conclusion, our data suggest a novel mechanism through which both lfALR and sfALR protect mitochondria by promoting PINK1/Parkin-dependent mitophagy through FOXO3a activation.
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Gupta P, Venugopal SK. Augmenter of liver regeneration: A key protein in liver regeneration and pathophysiology. Hepatol Res 2018; 48:587-596. [PMID: 29633440 DOI: 10.1111/hepr.13077] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/10/2018] [Accepted: 03/29/2018] [Indexed: 12/22/2022]
Abstract
Liver is constantly exposed to pathogens, viruses, chemicals, and toxins, and several of them cause injury, leading to the loss of liver mass and sometimes resulting in cirrhosis and cancer. Under physiological conditions, liver can regenerate if the loss of cells is less than the proliferation of hepatocytes. If the loss is more than the proliferation, the radical treatment available is liver transplantation. Due to this reason, the search for an alternative therapeutic agent has been the focus of liver research. Liver regeneration is regulated by several growth factors; one of the key factors is augmenter of liver regeneration (ALR). Involvement of ALR has been reported in crucial processes such as oxidative phosphorylation, maintenance of mitochondria and mitochondrial biogenesis, and regulation of autophagy and cell proliferation. Augmenter of liver regeneration has been observed to be involved in liver regeneration by not only overcoming cell cycle inhibition but by maintaining the stem cell pool as well. These observations have created curiosity regarding the possible role of ALR in maintenance of liver health. Thus, this review brings a concise presentation of the work done in areas exploring the role of ALR in normal liver physiology and in liver health maintenance by fighting liver diseases, such as liver failure, non-alcoholic fatty liver disease/non-alcoholic steatohepatitis, viral infections, cirrhosis, and hepatocellular carcinoma.
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Affiliation(s)
- Parul Gupta
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, India
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Weiss TS, Lupke M, Ibrahim S, Buechler C, Lorenz J, Ruemmele P, Hofmann U, Melter M, Dayoub R. Attenuated lipotoxicity and apoptosis is linked to exogenous and endogenous augmenter of liver regeneration by different pathways. PLoS One 2017; 12:e0184282. [PMID: 28877220 PMCID: PMC5587239 DOI: 10.1371/journal.pone.0184282] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/21/2017] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) covers a spectrum from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. Free fatty acids (FFA) induce steatosis and lipo-toxicity and correlate with severity of NAFLD. In this study we aimed to investigate the role of exogenous and endogenous ALR (augmenter of liver regeneration) for FFA induced ER (endoplasmatic reticulum) -stress and lipoapoptosis. Primary human hepatocytes or hepatoma cells either treated with recombinant human ALR (rhALR, 15kDa) or expressing short form ALR (sfALR, 15kDa) were incubated with palmitic acid (PA) and analyzed for lipo-toxicity, -apoptosis, activation of ER-stress response pathways, triacylglycerides (TAG), mRNA and protein expression of lipid metabolizing genes. Both, exogenous rhALR and cytosolic sfALR reduced PA induced caspase 3 activity and Bax protein expression and therefore lipotoxicity. Endogenous sfALR but not rhALR treatment lowered TAG levels, diminished activation of ER-stress mediators C-Jun N-terminal kinase (JNK), X-box binding protein-1 (XBP1) and proapoptotic transcription factor C/EBP-homologous protein (CHOP), and reduced death receptor 5 protein expression. Cellular ALR exerts its lipid lowering and anti-apoptotic actions by enhancing FABP1, which binds toxic FFA, increasing mitochondrial β-oxidation by elevating the mitochondrial FFA transporter CPT1α, and decreasing ELOVL6, which delivers toxic FFA metabolites. We found reduced hepatic mRNA levels of ALR in a high fat diet mouse model, and of ALR and FOXA2, a transcription factor inducing ALR expression, in human steatotic as well as NASH liver samples, which may explain increased lipid deposition and reduced β-oxidation in NASH patients. Present study shows that exogenous and endogenous ALR reduce PA induced lipoapoptosis. Furthermore, cytosolic sfALR changes mRNA and protein expression of genes regulating lipid metabolism, reduces ER-stress finally impeding progression of NASH.
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Affiliation(s)
- Thomas S. Weiss
- Children’s University Hospital, University of Regensburg, Regensburg, Germany
- Center for Liver Cell Research, University of Regensburg Hospital, Regensburg, Germany
- * E-mail:
| | - Madeleine Lupke
- Children’s University Hospital, University of Regensburg, Regensburg, Germany
| | - Sara Ibrahim
- Children’s University Hospital, University of Regensburg, Regensburg, Germany
| | - Christa Buechler
- Department of Internal Medicine, University of Regensburg Hospital, Regensburg, Germany
| | - Julia Lorenz
- Children’s University Hospital, University of Regensburg, Regensburg, Germany
| | - Petra Ruemmele
- Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuernberg, Erlangen, Germany
| | - Ute Hofmann
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology and University of Tübingen, Stuttgart, Germany
| | - Michael Melter
- Children’s University Hospital, University of Regensburg, Regensburg, Germany
| | - Rania Dayoub
- Children’s University Hospital, University of Regensburg, Regensburg, Germany
- Department of Biochemistry and Microbiology, Faculty of Pharmacy, Damascus University, Damascus, Syria
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Kuimov AN, Zhozhikashvili AS, Manskikh VN, Platonova LV, Dyuzheva TG. Tankyrase Activity in Organs and Tissues of Mice. BIOCHEMISTRY (MOSCOW) 2017; 81:255-62. [PMID: 27262195 DOI: 10.1134/s0006297916030081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Tankyrase, one of the NAD+ ADP-ribosyltransferases, is a target for drugs developed for their anticancer and other pharmacological activities. We designed an assay for estimation of the inhibition or activation of the enzyme in preclinical studies. In mice, the highest specific activity of tankyrase was observed in thymus, spleen, pancreas, and bone marrow. In murine liver, tankyrase is active in ontogenesis and during reparative regeneration; however, the basal activity is hardly detectable in normal liver and most of other organs of adult animals. We suggest that tankyrase is a part of the tissue growth and repair machinery, while its age-dependent inhibition, when an organism stops growing, turns on phenoptosis.
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Affiliation(s)
- A N Kuimov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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Calderwood L, Holm IA, Teot LA, Anselm I. Adrenal Insufficiency in Mitochondrial Disease: A Rare Case of GFER-Related Mitochondrial Encephalomyopathy and Review of the Literature. J Child Neurol 2016; 31:190-4. [PMID: 26018198 DOI: 10.1177/0883073815587327] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 04/24/2015] [Indexed: 11/15/2022]
Abstract
GFER-related mitochondrial encephalomyopathy has been previously described only in 3 siblings of a consanguineous Moroccan family. Their phenotype included congenital cataracts, hypotonia, developmental delay, and sensorineural hearing loss. Multiple mitochondrial respiratory chain complex deficiencies were identified on muscle biopsy. We describe a now-19-year-old woman with adrenal insufficiency, lactic acidosis, congenital cataracts, and respiratory insufficiency secondary to mitochondrial disorder, who was reported by North et al (1996) as a toddler. Compound heterozygous GFER mutations c.373C>T (Q125X) and c.581G>A (R194 H) were recently discovered in this patient. The purpose of this report is (1) to expand the phenotype this ultra-rare disorder and (2) to provide a review of the literature describing the unique finding of adrenal insufficiency in patients with molecularly confirmed disorders of mitochondrial metabolism.
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Affiliation(s)
- Laurel Calderwood
- Department of Obstetrics and Gynecology, Boston University School of Medicine, Boston, MA, USA
| | - Ingrid A Holm
- Division of Genetics and Genomics, Division of Endocrinology, Department of Medicine, Manton Center for Orphan Diseases Research, Boston Children's Hospital, Boston, MA, USA Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Lisa A Teot
- Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Irina Anselm
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
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Yu HY, Zhu MH, Xiang DR, Li J, Sheng JF. High expression of 23 kDa protein of augmenter of liver regeneration (ALR) in human hepatocellular carcinoma. Onco Targets Ther 2014; 7:887-93. [PMID: 24940072 PMCID: PMC4051792 DOI: 10.2147/ott.s61531] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background Augmenter of liver regeneration (ALR) is an important polypeptide that participates in the process of liver regeneration. Two forms of ALR proteins are expressed in hepatocytes. Previous data have shown that ALR is essential for cell survival and has potential antimetastatic properties in hepatocellular carcinoma (HCC). Aims The study aimed to evaluate the expression levels of two forms of ALR proteins in HCC and their possible significance in HCC development. Methods Balb/c mouse monoclonal antibody against ALR protein was prepared in order to detect the ALR protein in HCC by Western blotting and immunohistochemistry. ALR mRNA expression levels were measured by real-time polymerase chain reaction in HCC tissues and compared to paracancerous liver tissues in 22 HCC patients. Results ALR mRNA expression in HCC liver tissues (1.51×106 copies/μL) was higher than in paracancerous tissues (1.04×104 copies/μL). ALR protein expression was also enhanced in HCC liver tissues. The enhanced ALR protein was shown to be 23 kDa by Western blotting. Immunohistochemical analysis showed that the 23 kDa ALR protein mainly existed in the hepatocyte cytosol. Conclusion The 23 kDa ALR protein was highly expressed in HCC and may play an important role in hepatocarcinogenesis.
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Affiliation(s)
- Hai-Ying Yu
- State Key Laboratory of Infectious Disease and Department of Infectious Disease, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Man-Hua Zhu
- State Key Laboratory of Infectious Disease and Department of Infectious Disease, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Dai-Rong Xiang
- State Key Laboratory of Infectious Disease and Department of Infectious Disease, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Jun Li
- State Key Laboratory of Infectious Disease and Department of Infectious Disease, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Ji-Fang Sheng
- State Key Laboratory of Infectious Disease and Department of Infectious Disease, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
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Zhang J, Li Y, Jiang S, Yu H, An W. Enhanced endoplasmic reticulum SERCA activity by overexpression of hepatic stimulator substance gene prevents hepatic cells from ER stress-induced apoptosis. Am J Physiol Cell Physiol 2013; 306:C279-90. [PMID: 24284796 DOI: 10.1152/ajpcell.00117.2013] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Although the potential pathogenesis of nonalcoholic fatty liver disease (NAFLD) is unclear, increasing evidence indicates that endoplasmic reticulum (ER) stress may link free fatty acids to NAFLD. Since we previously reported that hepatic stimulator substance (HSS) could protect the liver from steatosis, this study is aimed to investigate whether HSS protection could be related with its inhibition on ER stress. The HSS gene was stably transfected into BEL-7402 hepatoma cells and effectively expressed in ER. The palmitic acid (PA)-induced heptocyte lipotoxicity was reproduced in the HSS-transfected cells, and HSS alleviation of the ER stress and apoptosis were subsequently examined. The results showed that PA treatment led to a heavy accumulation of fatty acids within the cells and a remarkable increase in reactive oxygen species (ROS). However, in the HSS-expressing cells, production of ROS was inhibited and ER stress-related marker glucose-regulated protein 78 (GRP-78), sterol regulatory element-binding protein (SREBP), anti-phospho-PRK-1ike ER kinase (p-PERK), anti-phospho-eukaryotic initiation factor 2α (p-eIF2α), and anti-C/EBP homologous protein (CHOP) were downregulated compared with the wild-type or mutant HSS-transfected cells. Furthermore, PA treatment severely impaired the activity of sarco-endoplasmic reticulum Ca(2+)-ATPase (SERCA), leading to imbalanced calcium homeostasis during ER stress, which could be rescued in the HSS-trasfected cells. The protection provided by HSS to the SERCA is identical to that observed with N-acetyl-l-cysteine (NAC) and sodium dimercaptopropane sulfonate (Na-DMPS), which are two typical free radical scavengers. As a consequence, the rate of ER stress-mediated apoptosis in the HSS-expressing cells was significantly reduced. In conclusion, the protective effect of HSS against ER stress may be associated with the removal of ROS to restore the activity of the SERCA.
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Affiliation(s)
- Jing Zhang
- Department of Cell Biology and Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, China
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Schaefer-Ramadan S, Gannon SA, Thorpe C. Human augmenter of liver regeneration: probing the catalytic mechanism of a flavin-dependent sulfhydryl oxidase. Biochemistry 2013; 52:8323-32. [PMID: 24147449 DOI: 10.1021/bi401305w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Augmenter of liver regeneration is a member of the ERV family of small flavin-dependent sulfhydryl oxidases that contain a redox-active CxxC disulfide bond in redox communication with the isoalloxazine ring of bound FAD. These enzymes catalyze the oxidation of thiol substrates with the reduction of molecular oxygen to hydrogen peroxide. This work studies the catalytic mechanism of the short, cytokine form of augmenter of liver regeneration (sfALR) using model thiol substrates of the enzyme. The redox potential of the proximal disulfide in sfALR was found to be approximately 57 mV more reducing than the flavin chromophore, in agreement with titration experiments. Rapid reaction studies show that dithiothreitol (DTT) generates a transient mixed disulfide intermediate with sfALR signaled by a weak charge-transfer interaction between the thiolate of C145 and the oxidized flavin. The subsequent transfer of reducing equivalents to the flavin ring is relatively slow, with a limiting apparent rate constant of 12.4 s(-1). However, reoxidation of the reduced flavin by molecular oxygen is even slower (2.3 s(-1) at air saturation) and thus largely limits turnover at 5 mM DTT. The nature of the charge-transfer complexes observed with DTT was explored using a range of simple monothiols to mimic the initial nucleophilic attack on the proximal disulfide. While β-mercaptoethanol is a very poor substrate of sfALR (∼0.3 min(-1) at 100 mM thiol), it rapidly generates a mixed disulfide intermediate allowing the thiolate of C145 to form a strong charge-transfer complex with the flavin. Unlike the other monothiols tested, glutathione is unable to form charge-transfer complexes and is an undetectable substrate of the oxidase. These data are rationalized on the basis of the stringent steric requirements for thiol-disulfide exchange reactions. The inability of the relatively bulky glutathione to attain the in-line geometry required for efficient disulfide exchange in sfALR may be physiologically important in preventing the oxidase from catalyzing the potentially harmful oxidation of intracellular glutathione.
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Affiliation(s)
- Stephanie Schaefer-Ramadan
- Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716-2522, United States
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Kallergi E, Kalef-Ezra E, Karagouni-Dalakoura K, Tokatlidis K. Common Players in Mitochondria Biogenesis and Neuronal Protection Against Stress-Induced Apoptosis. Neurochem Res 2013; 39:546-55. [DOI: 10.1007/s11064-013-1109-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/01/2013] [Accepted: 07/08/2013] [Indexed: 10/26/2022]
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Dayoub R, Vogel A, Schuett J, Lupke M, Spieker SM, Kettern N, Hildt E, Melter M, Weiss TS. Nrf2 activates augmenter of liver regeneration (ALR) via antioxidant response element and links oxidative stress to liver regeneration. Mol Med 2013; 19:237-44. [PMID: 23887691 DOI: 10.2119/molmed.2013.00027] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 07/22/2013] [Indexed: 12/12/2022] Open
Abstract
Liver regeneration can be impaired by permanent oxidative stress and activation of nuclear factor erythroid 2-related factor 2 (Nrf2), known to regulate the cellular antioxidant response, and has been shown to improve the process of liver regeneration. A variety of factors regulate hepatic tissue regeneration, among them augmenter of liver regeneration (ALR), attained great attention as being survival factors for the liver with proproliferative and antiapoptotic properties. Here we determined the Nrf2/antioxidant response element (ARE) regulated expression of ALR and show ALR as a target gene of Nrf2 in vitro and in vivo. The ALR promoter comprises an ARE binding site and, therefore, ALR expression can be induced by ARE-activator tertiary butylhydroquinone (tBHQ) in hepatoma cells and primary human hepatocytes (PHH). Promoter activity and expression of ALR were enhanced after cotransfection of Nrf2 compared with control and dominant negative mutant of Nrf2. Performing partial hepatectomy in livers from Nrf2+/+ mice compared with Nrf2-/- knock-out (KO) mice, we found increased expression of ALR in addition to known antioxidant ARE-regulated genes. Furthermore, we observed increased ALR expression in hepatitis B virus (HBV) compared with hepatitis C virus (HCV) positive hepatoma cells and PHH. Recently, it was demonstrated that HBV infection activates Nrf2 and, now, we add results showing increased ALR expression in liver samples from patients infected with HBV. ALR is regulated by Nrf2, acts as a liver regeneration and antioxidative protein and, therefore, links oxidative stress to hepatic regeneration to ensure survival of damaged cells.
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Affiliation(s)
- Rania Dayoub
- Department of Pediatrics and Juvenile Medicine, University of Regensburg Hospital, Germany
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Yi X, Song M, Yuan Y, Zhang X, Chen W, Li J, Tong M, Liu G, You S, Kong X. Hepatic stimulator substance alleviates toxin-induced and immune-mediated liver injury and fibrosis in rats. Dig Dis Sci 2012; 57:2079-87. [PMID: 22539040 DOI: 10.1007/s10620-012-2168-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 04/03/2012] [Indexed: 02/06/2023]
Abstract
BACKGROUND Liver fibrosis is a common scarring response to chronic liver injury. It is a precursor to cirrhosis and liver carcinoma. Hepatic stimulator substance (HSS), a known liver-specific but species-nonspecific growth factor, has been shown to protect hepatocytes from various toxins. METHODS We have investigated the effects of HSS therapy on carbon tetrachloride (CCl(4))-induced and porcine-serum-mediated hepatic injury and fibrosis. We hypothesize that HSS might attenuate liver injury and fibrosis by suppressing oxidative stress, down-regulating profibrogenic factors, and blocking HSCs activation. RESULTS This report demonstrated that HSS therapy diminished α-smooth muscle actin expression, decreased intrahepatic reactive oxygen species (ROS) level, and down-regulated transforming growth factor (TGF)-β1, platelet-derived growth factor (PDGF)-BB, and tissue inhibitor of metalloproteinase (TIMP)-1 expression. In addition, HSS treatment significantly protected the liver from injury by improving liver function tests and histological architecture of the liver. CONCLUSIONS These results provided novel insights into the mechanisms of HSS in the protection of the liver. Our results suggested that HSS might be a therapeutic antifibrotic agent for the treatment of liver fibrosis.
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Affiliation(s)
- Xuerui Yi
- Key Laboratory of Liver Disease, Center of Infectious Diseases, Guangzhou 458 Hospital, Dongfengdonglu 801#, Guangzhou 510600, Guangdong, China
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Li Y, Farooq M, Sheng D, Chandramouli C, Lan T, Mahajan NK, Kini RM, Hong Y, Lisowsky T, Ge R. Augmenter of liver regeneration (alr) promotes liver outgrowth during zebrafish hepatogenesis. PLoS One 2012; 7:e30835. [PMID: 22292055 PMCID: PMC3266923 DOI: 10.1371/journal.pone.0030835] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 12/29/2011] [Indexed: 02/06/2023] Open
Abstract
Augmenter of Liver Regeneration (ALR) is a sulfhydryl oxidase carrying out fundamental functions facilitating protein disulfide bond formation. In mammals, it also functions as a hepatotrophic growth factor that specifically stimulates hepatocyte proliferation and promotes liver regeneration after liver damage or partial hepatectomy. Whether ALR also plays a role during vertebrate hepatogenesis is unknown. In this work, we investigated the function of alr in liver organogenesis in zebrafish model. We showed that alr is expressed in liver throughout hepatogenesis. Knockdown of alr through morpholino antisense oligonucleotide (MO) leads to suppression of liver outgrowth while overexpression of alr promotes liver growth. The small-liver phenotype in alr morphants results from a reduction of hepatocyte proliferation without affecting apoptosis. When expressed in cultured cells, zebrafish Alr exists as dimer and is localized in mitochondria as well as cytosol but not in nucleus or secreted outside of the cell. Similar to mammalian ALR, zebrafish Alr is a flavin-linked sulfhydryl oxidase and mutation of the conserved cysteine in the CxxC motif abolishes its enzymatic activity. Interestingly, overexpression of either wild type Alr or enzyme-inactive Alr(C131S) mutant promoted liver growth and rescued the liver growth defect of alr morphants. Nevertheless, alr(C131S) is less efficacious in both functions. Meantime, high doses of alr MOs lead to widespread developmental defects and early embryonic death in an alr sequence-dependent manner. These results suggest that alr promotes zebrafish liver outgrowth using mechanisms that are dependent as well as independent of its sulfhydryl oxidase activity. This is the first demonstration of a developmental role of alr in vertebrate. It exemplifies that a low-level sulfhydryl oxidase activity of Alr is essential for embryonic development and cellular survival. The dose-dependent and partial suppression of alr expression through MO-mediated knockdown allows the identification of its late developmental role in vertebrate liver organogenesis.
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Affiliation(s)
- Yan Li
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Muhammad Farooq
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Department of Zoology, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Donglai Sheng
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Chanchal Chandramouli
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Tian Lan
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Nilesh K. Mahajan
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - R. Manjunatha Kini
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Department of Biochemistry and Molecular Biology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Yunhan Hong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | | | - Ruowen Ge
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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15
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Augmenter of liver regeneration (ALR) gene therapy attenuates CCl₄-induced liver injury and fibrosis in rats. Biochem Biophys Res Commun 2011; 415:152-6. [PMID: 22033404 DOI: 10.1016/j.bbrc.2011.10.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 10/09/2011] [Indexed: 01/09/2023]
Abstract
Liver fibrosis represents a process of healing and scarring in response to chronic liver injury. Augmenter of liver regeneration (ALR) has been shown to protect hepatocytes from various toxins. The aim of this study was to investigate the effects of ALR gene therapy on liver injury and fibrosis induced by CCl(4) in rats and further explore the underlying mechanisms. Human ALR expression plasmid was delivered via the tail vein. ALR gene therapy might protect the liver from CCl(4)-induced injury and fibrogenesis by attenuating the mitochondrial dysfunction, suppressing oxidative stress, and inhibiting activation of HSCs. This report demonstrated that ALR gene therapy protected against the ATP loss, increased the activity of ATPase, decreased intrahepatic reactive oxygen species level, and down-regulated transforming growth factor-β1, platelet-derived growth factor-BB, and α-smooth muscle actin expression. Following gene transfer liver function tests were significantly improved. In brief, ALR gene therapy might be an effective therapeutic reagent for liver fibrosis with potential clinical applications.
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16
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Kim RD, Kim JS, Watanabe G, Mohuczy D, Behrns KE. Liver regeneration and the atrophy-hypertrophy complex. Semin Intervent Radiol 2011; 25:92-103. [PMID: 21326550 DOI: 10.1055/s-2008-1076679] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The atrophy-hypertrophy complex (AHC) refers to the controlled restoration of liver parenchyma following hepatocyte loss. Different types of injury (e.g., toxins, ischemia/reperfusion, biliary obstruction, and resection) elicit the same hypertrophic response in the remnant liver. The AHC involves complex anatomical, histological, cellular, and molecular processes. The signals responsible for these processes are both intrinsic and extrinsic to the liver and involve both physical and molecular events. In patients in whom resection of large liver malignancies would result in an inadequate functional liver remnant, preoperative portal vein embolization may increase the remnant liver sufficiently to permit aggressive resections. Through continued basic science research, the cellular mechanisms of the AHC may be maximized to permit curative resections in patients with potentially prohibitive liver function.
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Affiliation(s)
- Robin D Kim
- Department of Surgery, Division of General and GI Surgery, University of Florida, Gainesville, Florida
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17
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Molecular recognition and substrate mimicry drive the electron-transfer process between MIA40 and ALR. Proc Natl Acad Sci U S A 2011; 108:4811-6. [PMID: 21383138 DOI: 10.1073/pnas.1014542108] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Oxidative protein folding in the mitochondrial intermembrane space requires the transfer of a disulfide bond from MIA40 to the substrate. During this process MIA40 is reduced and regenerated to a functional state through the interaction with the flavin-dependent sulfhydryl oxidase ALR. Here we present the mechanistic basis of ALR-MIA40 interaction at atomic resolution by biochemical and structural analyses of the mitochondrial ALR isoform and its covalent mixed disulfide intermediate with MIA40. This ALR isoform contains a folded FAD-binding domain at the C-terminus and an unstructured, flexible N-terminal domain, weakly and transiently interacting one with the other. A specific region of the N-terminal domain guides the interaction with the MIA40 substrate binding cleft (mimicking the interaction of the substrate itself), without being involved in the import of ALR. The hydrophobicity-driven binding of this region ensures precise protein-protein recognition needed for an efficient electron transfer process.
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18
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Teng EC, Todd LR, Ribar TJ, Lento W, Dimascio L, Means AR, Sankar U. Gfer inhibits Jab1-mediated degradation of p27kip1 to restrict proliferation of hematopoietic stem cells. Mol Biol Cell 2011; 22:1312-20. [PMID: 21346186 PMCID: PMC3078070 DOI: 10.1091/mbc.e10-08-0723] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Genes that promote hematopoietic stem cell (HSC) quiescence play important roles in the maintenance of their function. Here we show a novel role for the evolutionarily conserved flavin adenine dinucleotide (FAD)-dependent sulfhydryl oxidase, growth factor erv1-like (Gfer) in the restriction of HSC proliferation through its inhibition of Jab1-mediated turnover of p27kip1. Growth factor erv1-like (Gfer) is an evolutionarily conserved sulfhydryl oxidase that is enriched in embryonic and adult stem cells and plays an essential prosurvival role in pluripotent embryonic stem cells. Here we show that knockdown (KD) of Gfer in hematopoietic stem cells (HSCs) compromises their in vivo engraftment potential and triggers a hyper-proliferative response that leads to their exhaustion. KD of Gfer in HSCs does not elicit a significant alteration of mitochondrial morphology or loss of cell viability. However, these cells possess significantly reduced levels of the cyclin-dependent kinase inhibitor p27kip1. In contrast, overexpression of Gfer in HSCs results in significantly elevated total and nuclear p27kip1. KD of Gfer results in enhanced binding of p27kip1 to its inhibitor, the COP9 signalosome subunit jun activation-domain binding protein 1 (Jab1), leading to its down-regulation. Conversely, overexpression of Gfer results in its enhanced binding to Jab1 and inhibition of the Jab1-p27kip1 interaction. Furthermore, normalization of p27kip1 in Gfer-KD HSCs rescues their in vitro proliferation deficits. Taken together, our data demonstrate the presence of a novel Gfer-Jab1-p27kip1 pathway in HSCs that functions to restrict abnormal proliferation.
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Affiliation(s)
- Ellen C Teng
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27707, USA
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19
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Dayoub R, Wagner H, Bataille F, Stöltzing O, Spruss T, Buechler C, Schlitt HJ, Weiss TS. Liver regeneration associated protein (ALR) exhibits antimetastatic potential in hepatocellular carcinoma. Mol Med 2010; 17:221-8. [PMID: 21152698 DOI: 10.2119/molmed.2010.00117] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 12/02/2010] [Indexed: 01/17/2023] Open
Abstract
Augmenter of liver regeneration (ALR), which is critically important in liver regeneration and hepatocyte proliferation, is highly expressed in cirrhotic livers and hepatocellular carcinomas (HCC). In the current study, the functional role of ALR in hepatocancerogenesis was analyzed in more detail. HepG2 cells, in which the cytosolic 15 kDa ALR isoform was reexpressed stably, (HepG2-ALR) were used in migration and invasion assays using modified Boyden chambers. Epithelial-mesenchymal transition (EMT) markers were determined in HepG2-ALR cells in vitro and in HepG2-ALR tumors grown in nude mice. ALR protein was quantified in HCC and nontumorous tissues by immunohistochemistry. HepG2-ALR, compared with HepG2 cells, demonstrated reduced cell motility and increased expression of the epithelial cell markers E-cadherin and Zona occludens-1 (ZO-1), whereas SNAIL, a negative regulator of E-cadherin, was diminished. Matrix metalloproteinase MMP1 and MMP3 mRNA expression and activity were reduced. HepG2-ALR cell-derived subcutaneously grown tumors displayed fewer necrotic areas, more epithelial-like cell growth and fewer polymorphisms and atypical mitotic figures than tumors derived from HepG2 cells. Analysis of tumor tissues of 53 patients with HCC demonstrated an inverse correlation of ALR protein with histological angioinvasion and grading. The 15 kDa ALR isoform was found mainly in HCC tissues without histological angioinvasion 0. In summary the present data indicate that cytosolic ALR reduces hepatoma cell migration, augments epithelial growth and, therefore, may act as an antimetastatic and EMT reversing protein.
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Affiliation(s)
- Rania Dayoub
- Center for Liver Cell Research, University Medical Center Regensburg, Germany
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20
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Li Z, Ping X, Ye Q, Huang X, Cao Z. Production and optimization of recombinant human augmenter of liver regeneration by Pichia pastoris. Enzyme Microb Technol 2010. [DOI: 10.1016/j.enzmictec.2010.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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21
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Daithankar VN, Schaefer SA, Dong M, Bahnson BJ, Thorpe C. Structure of the human sulfhydryl oxidase augmenter of liver regeneration and characterization of a human mutation causing an autosomal recessive myopathy . Biochemistry 2010; 49:6737-45. [PMID: 20593814 DOI: 10.1021/bi100912m] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The sulfhydryl oxidase augmenter of liver regeneration (ALR) binds FAD in a helix-rich domain that presents a CxxC disulfide proximal to the isoalloxazine ring of the flavin. Head-to-tail interchain disulfide bonds link subunits within the homodimer of both the short, cytokine-like, form of ALR (sfALR), and a longer form (lfALR) which resides in the mitochondrial intermembrane space (IMS). lfALR has an 80-residue N-terminal extension with an additional CxxC motif required for the reoxidation of reduced Mia40 during oxidative protein folding within the IMS. Recently, Di Fonzo et al. [Di Fonzo, A., Ronchi, D., Lodi, T., Fassone, E., Tigano, M., Lamperti, C., Corti, S., Bordoni, A., Fortunato, F., Nizzardo, M., Napoli, L., Donadoni, C., Salani, S., Saladino, F., Moggio, M., Bresolin, N., Ferrero, I., and Comi, G. P. (2009) Am. J. Hum. Genet. 84, 594-604] described an R194H mutation of human ALR that led to cataract, progressive muscle hypotonia, and hearing loss in three children. The current work presents a structural and enzymological characterization of the human R194H mutant in lf- and sfALR. A crystal structure of human sfALR was determined by molecular replacement using the rat sfALR structure. R194 is located at the subunit interface of sfALR, close to the intersubunit disulfide bridges. The R194 guanidino moiety participates in three H-bonds: two main-chain carbonyl oxygen atoms (from R194 itself and from C95 of the intersubunit disulfide of the other protomer) and with the 2'-OH of the FAD ribose. The R194H mutation has minimal effect on the enzyme activity using model and physiological substrates of short and long ALR forms. However, the mutation adversely affects the stability of both ALR forms: e.g., by decreasing the melting temperature by about 10 degrees C, by increasing the rate of dissociation of FAD from the holoenzyme by about 45-fold, and by strongly enhancing the susceptibility of sfALR to partial proteolysis and to reduction of its intersubunit disulfide bridges by glutathione. Finally, a comparison of the TROSY-HSQC 2D NMR spectra of wild-type sfALR and its R194H mutant reveals a significant increase in conformational flexibility in the mutant protein. In sum, these in vitro data document the major impact of the seemingly conservative R194H mutation on the stability of dimeric ALR and complement the in vivo observations of Di Fonzo et al.
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Affiliation(s)
- Vidyadhar N Daithankar
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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22
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Dayoub R, Groitl P, Dobner T, Bosserhoff AK, Schlitt HJ, Weiss TS. Foxa2 (HNF-3beta) regulates expression of hepatotrophic factor ALR in liver cells. Biochem Biophys Res Commun 2010; 395:465-70. [PMID: 20382118 DOI: 10.1016/j.bbrc.2010.04.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 04/03/2010] [Indexed: 12/11/2022]
Abstract
Liver regeneration is a multistep and well-orchestrated process which is initiated by injuries such as tissue loss, infectious or toxic insults. Augmenter of liver regeneration (ALR) is a hepatotrophic growth factor which has been shown to stimulate hepatic regeneration after partial hepatectomy and therefore seems to be regulated during the regenerative process in the liver. Our aim was to analyze how ALR is regulated in hepatic tissues and which transcription factors might regulate its tissue-specific expression. Promoter studies of ALR (-733/+527 bp) revealed potential regulatory elements for various transcription factors like Foxa2, IL-6 RE-BP and C/EBPbeta. Analysis of the promoter activity by performing luciferase assays revealed that co-transfection with Foxa2 significantly induced the activity of ALR promoter in HepG2 cells. EMSA and Supershift analysis using anti-Foxa2 antibody confirmed the specific binding of Foxa2 to ALR promoter and this binding was inducible when the cells were simultaneously stimulated with IL-6. The increased binding after activation with IL-6 and/or Foxa2 was confirmed by elevated ALR protein levels using Western blot technique. In addition, we could not detect any binding of C/EBPbeta and IL-6 RE-BP to the promoter of ALR. In conclusion, these results indicate that ALR is regulated by Foxa2, and this regulation may be amplified by IL-6.
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Affiliation(s)
- Rania Dayoub
- Center for Liver Cell Research, University Medical Center Regensburg, Germany
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23
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Todd LR, Damin MN, Gomathinayagam R, Horn SR, Means AR, Sankar U. Growth factor erv1-like modulates Drp1 to preserve mitochondrial dynamics and function in mouse embryonic stem cells. Mol Biol Cell 2010; 6:821-2. [PMID: 20147447 PMCID: PMC2847526 DOI: 10.1091/mbc.e09-11-0937] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The relationship of mitochondrial dynamics and function to pluripotency are rather poorly understood aspects of stem cell biology. Here we show that growth factor erv1-like (Gfer) is involved in preserving mouse embryonic stem cell (ESC) mitochondrial morphology and function. Knockdown (KD) of Gfer in ESCs leads to decreased pluripotency marker expression, embryoid body (EB) formation, cell survival, and loss of mitochondrial function. Mitochondria in Gfer-KD ESCs undergo excessive fragmentation and mitophagy, whereas those in ESCs overexpressing Gfer appear elongated. Levels of the mitochondrial fission GTPase dynamin-related protein 1 (Drp1) are highly elevated in Gfer-KD ESCs and decreased in Gfer-overexpressing cells. Treatment with a specific inhibitor of Drp1 rescues mitochondrial function and apoptosis, whereas expression of Drp1-dominant negative resulted in the restoration of pluripotency marker expression in Gfer-KD ESCs. Altogether, our data reveal a novel prosurvival role for Gfer in maintaining mitochondrial fission-fusion dynamics in pluripotent ESCs.
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Affiliation(s)
- Lance R Todd
- James Graham Brown Cancer Center, University of Louisville, Owensboro, KY 42303, USA
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24
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Wu Y, Zhang J, Dong L, Li W, Jia J, An W. Hepatic stimulator substance mitigates hepatic cell injury through suppression of the mitochondrial permeability transition. FEBS J 2010; 277:1297-309. [DOI: 10.1111/j.1742-4658.2010.07560.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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25
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Gribilas G, Zarros A, Zira A, Giaginis C, Tsourouflis G, Liapi C, Spiliopoulou C, Theocharis SE. Involvement of hepatic stimulator substance in experimentally induced fibrosis and cirrhosis in the rat. Dig Dis Sci 2009; 54:2367-76. [PMID: 19082714 DOI: 10.1007/s10620-008-0623-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 11/03/2008] [Indexed: 12/22/2022]
Abstract
Liver fibrosis results from sustained wound healing response to chronic liver injury. Liver cirrhosis, the end stage of the fibrotic process, is characterized by disruption of the entire liver architecture and reduced hepatocyte regenerative ability. Hepatic stimulator substance (HSS) is a liver-specific growth factor triggering hepatocyte proliferation in vitro and in vivo. Previous studies have indicated the involvement of HSS in animal models of acute liver injury. The aim of the present study was to investigate the involvement of HSS in the process of fibrosis and cirrhosis induction. Liver fibrosis and cirrhosis were induced in rats by thioacetamide (TAA) administration (300 mg/l) in the drinking water for 3 months, and animals were killed at 0, 1, 2, and 3 months of treatment. TAA administration resulted in progressively increasing liver fibrosis, leading to the onset of cirrhosis at the end of the experimental time. HSS was continuously produced during the course of fibrosis and cirrhosis induction, peaking at the 2nd month of TAA treatment, coinciding with markers of hepatic proliferative capacity, as thymidine kinase activity and DNA biosynthesis. Significantly reduced HSS activity was noted in cirrhotic liver (3rd month). In this case, the exogenous HSS administration during the 3rd month of TAA treatment suppressed the onset of liver cirrhosis, stimulating the hepatic regenerative capacity. Our data indicate the active participation of HSS in the process of fibrosis and cirrhosis induction post-TAA treatment in rats, suggesting also the beneficial effect of HSS treatment against cirrhosis induction with future possible clinical implications.
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Affiliation(s)
- Georgios Gribilas
- Department of Forensic Medicine and Toxicology, Medical School, National and Kapodistrian University of Athens, Goudi, 11527 Athens, Greece
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Daithankar VN, Farrell SR, Thorpe C. Augmenter of liver regeneration: substrate specificity of a flavin-dependent oxidoreductase from the mitochondrial intermembrane space. Biochemistry 2009; 48:4828-37. [PMID: 19397338 DOI: 10.1021/bi900347v] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Augmenter of liver regeneration (ALR) is both a growth factor and a sulfhydryl oxidase that binds FAD in an unusual helix-rich domain containing a redox-active CxxC disulfide proximal to the flavin ring. In addition to the cytokine form of ALR (sfALR) that circulates in serum, a longer form, lfALR, is believed to participate in oxidative trapping of reduced proteins entering the mitochondrial intermembrane space (IMS). This longer form has an 80-residue N-terminal extension containing an additional, distal, CxxC motif. This work presents the first enzymological characterization of human lfALR. The N-terminal region conveys no catalytic advantage toward the oxidation of the model substrate dithiothreitol (DTT). In addition, a C71A or C74A mutation of the distal disulfide does not increase the turnover number toward DTT. Unlike Erv1p, the yeast homologue of lfALR, static spectrophotometric experiments with the human oxidase provide no evidence of communication between distal and proximal disulfides. An N-terminal His-tagged version of human Mia40, a resident oxidoreductase of the IMS and a putative physiological reductant of lfALR, was subcloned and expressed in Escherichia coli BL21 DE3 cells. Mia40, as isolated, shows a visible spectrum characteristic of an Fe-S center and contains 0.56 +/- 0.02 atom of iron per subunit. Treatment of Mia40 with guanidine hydrochloride and triscarboxyethylphosphine hydrochloride during purification removed this chromophore. The resulting protein, with a reduced CxC motif, was a good substrate of lfALR. However, neither sfALR nor lfALR mutants lacking the distal disulfide could oxidize reduced Mia40 efficiently. Thus, catalysis involves a flow of reducing equivalents from the reduced CxC motif of Mia40 to distal and then proximal CxxC motifs of lfALR to the flavin ring and, finally, to cytochrome c or molecular oxygen.
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Affiliation(s)
- Vidyadhar N Daithankar
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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Majji S, Thodima V, Sample R, Whitley D, Deng Y, Mao J, Chinchar VG. Transcriptome analysis of Frog virus 3, the type species of the genus Ranavirus, family Iridoviridae. Virology 2009; 391:293-303. [PMID: 19608212 DOI: 10.1016/j.virol.2009.06.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 05/19/2009] [Accepted: 06/06/2009] [Indexed: 01/04/2023]
Abstract
Frog virus 3 is the best characterized species within the genus Ranavirus, family Iridoviridae. FV3's large ( approximately 105 kbp) dsDNA genome encodes 98 putative open reading frames (ORFs) that are expressed in a coordinated fashion leading to the sequential appearance of immediate early (IE), delayed early (DE) and late (L) viral transcripts. As a step toward elucidating molecular events in FV3 replication, we sought to identify the temporal class of viral messages. To accomplish this objective an oligonucleotide microarray containing 70-mer probes corresponding to each of the 98 FV3 ORFs was designed and used to examine viral gene expression. Viral transcription was initially monitored during the course of a productive replication cycle at 2, 4 and 9 h after infection. To confirm results of the time course assay, viral gene expression was also monitored in the presence of cycloheximide (CHX), which limits expression to only IE genes, and following infection with a temperature-sensitive (ts) mutant which at non-permissive temperatures is defective in viral DNA synthesis and blocked in late gene expression. Subsequently, microarray analyses were validated by RT-PCR and qRT-PCR. Using these approaches we identified 33 IE genes, 22 DE genes and 36 L viral genes. The temporal class of the 7 remaining genes could not be determined. Comparison of protein function with temporal class indicated that, in general, genes encoding putative regulatory factors, or proteins that played a part in nucleic acid metabolism and immune evasion, were classified as IE and DE genes, whereas those involved in DNA packaging and virion assembly were considered L genes. Information on temporal class will provide the basis for determining whether members of the same temporal class contain common upstream regulatory regions and perhaps allow us to identify virion-associated and virus-induced proteins that control viral gene expression.
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Affiliation(s)
- S Majji
- Department of Microbiology, University of Mississippi Medical Ctr., 2500 North State Street, Jackson, MS 39216, USA
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28
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Di Fonzo A, Ronchi D, Lodi T, Fassone E, Tigano M, Lamperti C, Corti S, Bordoni A, Fortunato F, Nizzardo M, Napoli L, Donadoni C, Salani S, Saladino F, Moggio M, Bresolin N, Ferrero I, Comi GP. The mitochondrial disulfide relay system protein GFER is mutated in autosomal-recessive myopathy with cataract and combined respiratory-chain deficiency. Am J Hum Genet 2009; 84:594-604. [PMID: 19409522 DOI: 10.1016/j.ajhg.2009.04.004] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 03/13/2009] [Accepted: 04/08/2009] [Indexed: 11/28/2022] Open
Abstract
A disulfide relay system (DRS) was recently identified in the yeast mitochondrial intermembrane space (IMS) that consists of two essential components: the sulfhydryl oxidase Erv1 and the redox-regulated import receptor Mia40. The DRS drives the import of cysteine-rich proteins into the IMS via an oxidative folding mechanism. Erv1p is reoxidized within this system, transferring its electrons to molecular oxygen through interactions with cytochrome c and cytochrome c oxidase (COX), thereby linking the DRS to the respiratory chain. The role of the human Erv1 ortholog, GFER, in the DRS has been poorly explored. Using homozygosity mapping, we discovered that a mutation in the GFER gene causes an infantile mitochondrial disorder. Three children born to healthy consanguineous parents presented with progressive myopathy and partial combined respiratory-chain deficiency, congenital cataract, sensorineural hearing loss, and developmental delay. The consequences of the mutation at the level of the patient's muscle tissue and fibroblasts were 1) a reduction in complex I, II, and IV activity; 2) a lower cysteine-rich protein content; 3) abnormal ultrastructural morphology of the mitochondria, with enlargement of the IMS space; and 4) accelerated time-dependent accumulation of multiple mtDNA deletions. Moreover, the Saccharomyces cerevisiae erv1(R182H) mutant strain reproduced the complex IV activity defect and exhibited genetic instability of the mtDNA and mitochondrial morphological defects. These findings shed light on the mechanisms of mitochondrial biogenesis, establish the role of GFER in the human DRS, and promote an understanding of the pathogenesis of a new mitochondrial disease.
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Affiliation(s)
- Alessio Di Fonzo
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, 20122 Milan, Italy
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29
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Gao CF, Zhou FG, Wang H, Huang YF, Ji Q, Chen J. Genetic recombinant expression and characterization of human augmenter of liver regeneration. Dig Dis Sci 2009; 54:530-7. [PMID: 18612818 DOI: 10.1007/s10620-008-0372-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Accepted: 06/03/2008] [Indexed: 12/09/2022]
Abstract
AIMS To establish a highly effective prokaryotic recombinant expression system for human augmenter of liver regeneration (hALR) and to characterize the recombinant hALR both in vitro and in vivo. METHODS ALR cDNA was synthesized and inserted into expression vector pET28a+, the recombinant plasmid was transformed into BL21, and expression of hALR was induced by IPTG. Recombinant hALR (rhALR) was purified by sequential detergent wash, enterokinase (EK) digestion, gel-filtration, and chelating chromatography. The rhALR was identified by SDS-PAGE, immunoblotting, MALDI-TOF-MS, and N-terminal sequencer. Cell proliferative effect of rhALR on human hepatocytes was analyzed by MTT. The protective effect of rhALR on liver function was observed on CCl(4)-induced intoxicated mice. RESULTS Recombinant expression plasmid of ALR [pET28(a+)-hALR] was confirmed by restriction enzyme digestion and DNA sequencing. The expressed rhALR constituted 30% of total bacterial protein. Molecular weight was 15,029 for monomer and 30,136 for dimer by mass determination. N-terminal was M-R-T-Q-Q, exactly the same as anticipated for hALR. The purified protein migrating at about 15 KD showed excellent antigenicity in immunoblotting. The rhALR also showed a strong stimulative effect on hepatocyte proliferation. ALT and AST levels, liver histological structure, as well as the survival rate of CCl(4)-intoxicated mice were significantly improved when rALR was administrated at 40 microg/kg or 200 microg/kg. CONCLUSIONS The rhALR is successfully expressed highly effectively with anticipated MW, N-terminal, and antigenicity. It could play an important role in relieving acute hepatic injury and hepatic failure by promoting hepatic cell proliferation and improving liver function in CCl(4)-intoxicated mice.
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Affiliation(s)
- Chun-Fang Gao
- Department of Laboratory Medicine, Eastern Hepatobiliary Hospital, Second Military Medical University, 225 Changhai Road, Shanghai, 200438, China.
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McClure KD, Sustar A, Schubiger G. Three genes control the timing, the site and the size of blastema formation in Drosophila. Dev Biol 2008; 319:68-77. [PMID: 18485344 DOI: 10.1016/j.ydbio.2008.04.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 04/02/2008] [Accepted: 04/03/2008] [Indexed: 10/22/2022]
Abstract
Regeneration is a vital process to maintain and repair tissues. Despite the importance of regeneration, the genes responsible for regenerative growth remain largely unknown. In Drosophila, imaginal disc regeneration can be induced either by fragmentation and in vivo culture or in situ by ubiquitous expression of wingless (wg/wnt1). Imaginal discs, like appendages in lower vertebrates, initiate regeneration by wound healing and proliferation at the wound site, forming a regeneration blastema. Most blastema cells maintain their disc-specific identity during regeneration; a few cells however, exhibit stem-cell like properties and switch to a different fate, in a phenomenon known as transdetermination. We identified three genes, regeneration (rgn), augmenter of liver regeneration (alr) and Matrix metalloproteinase-1 (Mmp1) expressed specifically in blastema cells during disc regeneration. Mutations in these genes affect both fragmentation- and wg-induced regeneration by either delaying, reducing or positioning the regeneration blastema. In addition to the modifications of blastema homeostasis, mutations in the three genes alter the rate of regeneration-induced transdetermination. We propose that these genes function in regenerative proliferation, growth and regulate cellular plasticity.
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Affiliation(s)
- Kimberly D McClure
- University of California, San Francisco, Department of Anatomy, 1550 4th Street, Rock Hall, Mail Code 2822, San Francisco, CA 94158, USA.
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Gene expression in diapause-destined embryos of the crustacean, Artemia franciscana. Mech Dev 2007; 124:856-67. [DOI: 10.1016/j.mod.2007.09.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 09/02/2007] [Accepted: 09/07/2007] [Indexed: 11/21/2022]
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