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Kang X, Shimada S, Miyahara H, Higuchi K, Mori M. BALB.NCT-Cpox is a unique mouse model of hereditary coproporphyria. Mol Genet Metab Rep 2023; 35:100964. [PMID: 36967721 PMCID: PMC10036863 DOI: 10.1016/j.ymgmr.2023.100964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/18/2023] Open
Abstract
In humans, mutations in the coproporphyrinogen oxidase (CPOX) gene can result in hereditary coproporphyria (HCP), characterized by high levels of coproporphyrin excretion in the urine and feces, as well as acute neurovisceral and chronic cutaneous manifestations. Appropriate animal models for comprehending the precise pathogenesis mechanism of HCP have not been reported that show similarities in terms of gene mutation, reduced CPOX activity, excess coproporphyrin accumulation, and clinical symptoms. As previously discovered, the BALB.NCT-Cpox nct mouse carries a hypomorphic mutation in the Cpox gene. Due to the mutation, BALB.NCT-Cpox nct had a drastic increase in coproporphyrin in the blood and liver persistently from a young age. In this study, we found that BALB.NCT-Cpox nct mice manifested HCP symptoms. Similar to HCP patients, BALB.NCT-Cpox nct excreted an excessive amount of coproporphyrin and porphyrin precursors in the urine and displayed neuromuscular symptoms, such as a lack of grip strength and impaired motor coordination. Male BALB.NCT-Cpox nct had nonalcoholic steatohepatitis (NASH)-like liver pathology and sclerodermatous skin pathology. A portion of male mice had liver tumors as well, whereas female BALB.NCT-Cpox nct lacked these hepatic and cutaneous pathologies. In addition, we discovered that BALB.NCT-Cpox nct exhibited microcytic anemia. These results indicate that BALB.NCT-Cpox nct mice serve as the suitable animal model to help gain insight into the pathogenesis and therapy of HCP.
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Husain H, Waseem M, Ahmad R. Proteomic and molecular evidences of Il1rl2, Ric8a, Krt18 and Hsp90b1 modulation during experimental hepatic fibrosis and pomegranate supplementation. Int J Biol Macromol 2021; 185:696-707. [PMID: 34174316 DOI: 10.1016/j.ijbiomac.2021.06.091] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 05/31/2021] [Accepted: 06/12/2021] [Indexed: 12/28/2022]
Abstract
The inspection of variations in the proteomic aspects conspire the biomarker discovery in diagnostics of peculiar diseases. Recent developments in high-throughput proteomic techniques have provided leverage in the discovery of biomarkers during the etiology of various diseases. We identified potential biomarkers by utilizing proteomics, bioinformatics and gene expression studies. Meticulous assessment of collagen and hydroxyproline levels along with the glycogen and protein carbonyl levels exhibited deterioration in the N' - Nitrosodiethylamine (NDEA) administered rat livers and subsequent salubrious effect of pomegranate juice. The immunohistochemical inspection of iNOS and nitrite estimation indicated the peccant fibrotic alterations. 2D proteome profiling and MALDI-TOF MS/MS furthered the significant biomarkers to be analyzed for the gene ontology by PANTHER, cluster analysis by DAVID and network simulation by STRING 10.0. Several genes found relevant after MALDI analysis were evaluated by real-time PCR (RTPCR). Our data revealed CYP2b15, HSP70, TRFE, HPT, Il1rl2, Ric8a, Krt18, Hsp90b1 and iNOS as novel biomarkers for the mechanism of pomegranate against liver fibrosis. It can be inferred that NDEA-induced liver fibrosis actuates various biological pathways by the identified biomarkers and pomegranate juice modifies them.
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Affiliation(s)
- Hadiya Husain
- Section of Genetics, Department of Zoology, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, U.P, India
| | - Mohammad Waseem
- Department of Biochemistry, King George Medical University, Lucknow, India
| | - Riaz Ahmad
- Section of Genetics, Department of Zoology, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, U.P, India.
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Lim Y, Ku NO. Revealing the Roles of Keratin 8/18-Associated Signaling Proteins Involved in the Development of Hepatocellular Carcinoma. Int J Mol Sci 2021; 22:6401. [PMID: 34203895 PMCID: PMC8232640 DOI: 10.3390/ijms22126401] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/08/2021] [Accepted: 06/11/2021] [Indexed: 02/08/2023] Open
Abstract
Although hepatocellular carcinoma (HCC) is developed with various etiologies, protection of hepatocytes seems basically essential to prevent the incidence of HCC. Keratin 8 and keratin 18 (K8/K18) are cytoskeletal intermediate filament proteins that are expressed in hepatocytes. They maintain the cell shape and protect cells under stress conditions. Their protective roles in liver damage have been described in studies of mouse models, and K8/K18 mutation frequency in liver patients. Interestingly, K8/K18 bind to signaling proteins such as transcription factors and protein kinases involved in HCC development. Since K8/K18 are abundant cytoskeletal proteins, K8/K18 binding with the signaling factors can alter the availability of the factors. Herein, we discuss the potential roles of K8/K18 in HCC development.
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Affiliation(s)
- Younglan Lim
- Interdisciplinary Program of Integrated OMICS for Biomedical Sciences, Yonsei University, Seoul 03722, Korea;
| | - Nam-On Ku
- Interdisciplinary Program of Integrated OMICS for Biomedical Sciences, Yonsei University, Seoul 03722, Korea;
- Department of Bio-Convergence ISED, Underwood International College, Yonsei University, Seoul 03722, Korea
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Keratin intermediate filaments in the colon: guardians of epithelial homeostasis. Int J Biochem Cell Biol 2020; 129:105878. [PMID: 33152513 DOI: 10.1016/j.biocel.2020.105878] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/24/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022]
Abstract
Keratin intermediate filament proteins are major cytoskeletal components of the mammalian simple layered columnar epithelium in the gastrointestinal tract. Human colon crypt epithelial cells express keratins 18, 19 and 20 as the major type I keratins, and keratin 8 as the type II keratin. Keratin expression patterns vary between species, and mouse colonocytes express keratin 7 as a second type II keratin. Colonic keratin patterns change during cell differentiation, such that K20 increases in the more differentiated crypt cells closer to the central lumen. Keratins provide a structural and mechanical scaffold to support cellular stability, integrity and stress protection in this rapidly regenerating tissue. They participate in central colonocyte processes including barrier function, ion transport, differentiation, proliferation and inflammatory signaling. The cell-specific keratin compositions in different epithelial tissues has allowed for the utilization of keratin-based diagnostic methods. Since the keratin expression pattern in tumors often resembles that in the primary tissue, it can be used to recognize metastases of colonic origin. This review focuses on recent findings on the biological functions of mammalian colon epithelial keratins obtained from pivotal in vivo models. We also discuss the diagnostic value of keratins in chronic colonic disease and known keratin alterations in colon pathologies. This review describes the biochemical properties of keratins and their molecular actions in colonic epithelial cells and highlights diagnostic data in colorectal cancer and inflammatory bowel disease patients, which may facilitate the recognition of disease subtypes and the establishment of personal therapies in the future.
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Kramer N, Chen G, Ishan M, Cui X, Liu HX. Early taste buds are from Shh + epithelial cells of tongue primordium in distinction from mature taste bud cells which arise from surrounding tissue compartments. Biochem Biophys Res Commun 2019; 515:149-155. [PMID: 31133375 PMCID: PMC6953407 DOI: 10.1016/j.bbrc.2019.05.132] [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] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 05/20/2019] [Indexed: 12/24/2022]
Abstract
Mammalian taste buds emerge perinatally and most become mature 3-4 weeks after birth. Mature taste bud cells in rodents are known to be renewed by the surrounding K14+ basal epithelial cells and potentially other progenitor source(s), but the dynamics between initially developed taste buds and surrounding tissue compartments are unclear. Using the K14-Cre and Dermo1-Cre mouse lines to trace epithelial and mesenchymal cell lineages, we found that early taste buds in E18.5 and newborn mouse tongues are not derived from either lineage. At E11.5 when the tongue primordia (i.e., lingual swellings) emerge, the relatively homogeneous sonic hedgehog-expressing (Shh+) epithelial cells express Keratin (K) 8, a marker that is widely used to label taste buds. Mapping lineage of E11.0 Shh+ epithelium of the tongue rudiment with Shh-CreERT2/RFP mice demonstrated that both the early taste buds and the surrounding lingual epithelium are from the same population of progenitors - Shh+ epithelial cells of the tongue primordium. In combination with previous reports, we propose that Shh+K8+ cells in the homogeneous epithelium of tongue primordium at early embryonic stages are programmed to become taste papilla and taste bud cells. Switching off Shh and K8 expression in the Shh+ epithelial cells of the tongue primordium transforms the cells to non-gustatory cells surrounding papillae, including K14+ basal epithelial cells which will eventually contribute to the cell renewal of mature taste buds.
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Affiliation(s)
- Naomi Kramer
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA
| | - Guiqian Chen
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA
| | - Mohamed Ishan
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA
| | - Xiaogang Cui
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA
| | - Hong-Xiang Liu
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA.
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Response to the letter by Sumida et al. regarding our manuscript "Evaluation of ballooned hepatocytes as a risk factor for future progression of fibrosis in patients with non-alcoholic fatty liver disease". J Gastroenterol 2019; 54:476-477. [PMID: 30915534 DOI: 10.1007/s00535-019-01574-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 03/15/2019] [Indexed: 02/04/2023]
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Battaglia RA, Beltran AS, Delic S, Dumitru R, Robinson JA, Kabiraj P, Herring LE, Madden VJ, Ravinder N, Willems E, Newman RA, Quinlan RA, Goldman JE, Perng MD, Inagaki M, Snider NT. Site-specific phosphorylation and caspase cleavage of GFAP are new markers of Alexander disease severity. eLife 2019; 8:47789. [PMID: 31682229 PMCID: PMC6927689 DOI: 10.7554/elife.47789] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 11/04/2019] [Indexed: 12/28/2022] Open
Abstract
Alexander disease (AxD) is a fatal neurodegenerative disorder caused by mutations in glial fibrillary acidic protein (GFAP), which supports the structural integrity of astrocytes. Over 70 GFAP missense mutations cause AxD, but the mechanism linking different mutations to disease-relevant phenotypes remains unknown. We used AxD patient brain tissue and induced pluripotent stem cell (iPSC)-derived astrocytes to investigate the hypothesis that AxD-causing mutations perturb key post-translational modifications (PTMs) on GFAP. Our findings reveal selective phosphorylation of GFAP-Ser13 in patients who died young, independently of the mutation they carried. AxD iPSC-astrocytes accumulated pSer13-GFAP in cytoplasmic aggregates within deep nuclear invaginations, resembling the hallmark Rosenthal fibers observed in vivo. Ser13 phosphorylation facilitated GFAP aggregation and was associated with increased GFAP proteolysis by caspase-6. Furthermore, caspase-6 was selectively expressed in young AxD patients, and correlated with the presence of cleaved GFAP. We reveal a novel PTM signature linking different GFAP mutations in infantile AxD.
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Affiliation(s)
- Rachel A Battaglia
- Department of Cell Biology and PhysiologyUniversity of North CarolinaChapel HillUnited States
| | - Adriana S Beltran
- Department of PharmacologyUniversity of North CarolinaChapel HillUnited States,Human Pluripotent Stem Cell CoreUniversity of North CarolinaChapel HillUnited States
| | - Samed Delic
- Department of Cell Biology and PhysiologyUniversity of North CarolinaChapel HillUnited States,Department of BiosciencesUniversity of DurhamDurhamUnited Kingdom
| | - Raluca Dumitru
- Human Pluripotent Stem Cell CoreUniversity of North CarolinaChapel HillUnited States
| | - Jasmine A Robinson
- Department of Cell Biology and PhysiologyUniversity of North CarolinaChapel HillUnited States
| | - Parijat Kabiraj
- Department of Cell Biology and PhysiologyUniversity of North CarolinaChapel HillUnited States
| | - Laura E Herring
- Department of PharmacologyUniversity of North CarolinaChapel HillUnited States
| | - Victoria J Madden
- Department of PathologyUniversity of North CarolinaChapel HillUnited States
| | | | | | | | - Roy A Quinlan
- Department of BiosciencesUniversity of DurhamDurhamUnited Kingdom
| | - James E Goldman
- Department of PathologyColumbia UniversityNew YorkUnited States
| | - Ming-Der Perng
- Institute of Molecular MedicineNational Tsing Hua UniversityHsinchuTaiwan, Republic of China
| | - Masaki Inagaki
- Department of PhysiologyMie University Graduate School of MedicineMieJapan
| | - Natasha T Snider
- Department of Cell Biology and PhysiologyUniversity of North CarolinaChapel HillUnited States
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The role of keratins in the digestive system: lessons from transgenic mouse models. Histochem Cell Biol 2018; 150:351-359. [PMID: 30039330 DOI: 10.1007/s00418-018-1695-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2018] [Indexed: 01/17/2023]
Abstract
Keratins are the largest subfamily of intermediate filament proteins. They are either type I acidic or type II basic keratins. Keratins form obligate heteropolymer in epithelial cells and their expression patterns are tissue-specific. Studies have shown that keratin mutations are the cause of many diseases in humans or predispose humans to acquiring them. Using mouse models to study keratin-associated human diseases is critical, because they allow researchers to get a better understanding of these diseases and their progressions, and so many such studies have been conducted. Acknowledging the importance, researches with genetically modified mice expressing human disease-associated keratin mutants have been widely done. Numerous studies using keratin knockout mice, keratin-overexpressed mice, or transgenic mice expressing keratin mutants have been conducted. This review summarizes the mouse models that have been used to study type I and type II keratin expression in the digestive organs, namely, the liver, pancreas, and colon.
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Basisty NB, Liu Y, Reynolds J, Karunadharma PP, Dai DF, Fredrickson J, Beyer RP, MacCoss MJ, Rabinovitch PS. Stable Isotope Labeling Reveals Novel Insights Into Ubiquitin-Mediated Protein Aggregation With Age, Calorie Restriction, and Rapamycin Treatment. J Gerontol A Biol Sci Med Sci 2018; 73:561-570. [PMID: 28958078 PMCID: PMC6380815 DOI: 10.1093/gerona/glx047] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 08/16/2017] [Indexed: 12/30/2022] Open
Abstract
Accumulation of protein aggregates with age was first described in aged human tissue over 150 years ago and has since been described in virtually every human tissue. Ubiquitin modifications are a canonical marker of insoluble protein aggregates; however, the composition of most age-related inclusions remains relatively unknown. To examine the landscape of age-related protein aggregation in vivo, we performed an antibody-based pulldown of ubiquitinated proteins coupled with metabolic labeling and mass spectrometry on young and old mice on calorie restriction (CR), rapamycin (RP)-supplemented, and control diets. We show increased abundance of many ubiquitinated proteins in old mice and greater retention of preexisting (unlabeled) ubiquitinated proteins relative to their unmodified counterparts-fitting the expected profile of age-increased accumulation of long-lived aggregating proteins. Both CR and RP profoundly affected ubiquitinome composition, half-live, and the insolubility of proteins, consistent with their ability to mobilize these age-associated accumulations. Finally, confocal microscopy confirmed the aggregation of two of the top predicted aggregating proteins, keratins 8/18 and catalase, as well as their attenuation by CR and RP. Stable-isotope labeling is a powerful tool to gain novel insights into proteostasis mechanisms, including protein aggregation, and could be used to identify novel therapeutic targets in aging and protein aggregation diseases.
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Affiliation(s)
- Nathan B Basisty
- Department of Pathology, University of Washington, Seattle
- Buck Institute for Research on Aging, Novato, California
| | - Yuxin Liu
- Department of Medicine, SUNY Upstate Medical University, Syracuse, New York
| | - Jason Reynolds
- Department of Medicine, University of Washington, Seattle
| | | | - Dao-Fu Dai
- Department of Pathology, University of Washington, Seattle
- Department of Pathology, University of Iowa Carver College of Medicine, Iowa City
| | | | - Richard P Beyer
- Department of Environmental Health, University of Washington, Seattle
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Consequences of Keratin Phosphorylation for Cytoskeletal Organization and Epithelial Functions. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2017; 330:171-225. [DOI: 10.1016/bs.ircmb.2016.09.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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12
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Keratins Are Altered in Intestinal Disease-Related Stress Responses. Cells 2016; 5:cells5030035. [PMID: 27626448 PMCID: PMC5040977 DOI: 10.3390/cells5030035] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 08/18/2016] [Accepted: 08/25/2016] [Indexed: 12/17/2022] Open
Abstract
Keratin (K) intermediate filaments can be divided into type I/type II proteins, which form obligate heteropolymers. Epithelial cells express type I-type II keratin pairs, and K7, K8 (type II) and K18, K19 and K20 (type I) are the primary keratins found in the single-layered intestinal epithelium. Keratins are upregulated during stress in liver, pancreas, lung, kidney and skin, however, little is known about their dynamics in the intestinal stress response. Here, keratin mRNA, protein and phosphorylation levels were studied in response to murine colonic stresses modeling human conditions, and in colorectal cancer HT29 cells. Dextran sulphate sodium (DSS)-colitis was used as a model for intestinal inflammatory stress, which elicited a strong upregulation and widened crypt distribution of K7 and K20. K8 levels were slightly downregulated in acute DSS, while stress-responsive K8 serine-74 phosphorylation (K8 pS74) was increased. By eliminating colonic microflora using antibiotics, K8 pS74 in proliferating cells was significantly increased, together with an upregulation of K8 and K19. In the aging mouse colon, most colonic keratins were upregulated. In vitro, K8, K19 and K8 pS74 levels were increased in response to lipopolysaccharide (LPS)-induced inflammation in HT29 cells. In conclusion, intestinal keratins are differentially and dynamically upregulated and post-translationally modified during stress and recovery.
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Kumar V, Bouameur JE, Bär J, Rice RH, Hornig-Do HT, Roop DR, Schwarz N, Brodesser S, Thiering S, Leube RE, Wiesner RJ, Vijayaraj P, Brazel CB, Heller S, Binder H, Löffler-Wirth H, Seibel P, Magin TM. A keratin scaffold regulates epidermal barrier formation, mitochondrial lipid composition, and activity. J Cell Biol 2016; 211:1057-75. [PMID: 26644517 PMCID: PMC4674273 DOI: 10.1083/jcb.201404147] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Epidermal keratin filaments are important components and organizers of the cornified envelope and regulate mitochondrial metabolism by modulating their membrane composition. Keratin intermediate filaments (KIFs) protect the epidermis against mechanical force, support strong adhesion, help barrier formation, and regulate growth. The mechanisms by which type I and II keratins contribute to these functions remain incompletely understood. Here, we report that mice lacking all type I or type II keratins display severe barrier defects and fragile skin, leading to perinatal mortality with full penetrance. Comparative proteomics of cornified envelopes (CEs) from prenatal KtyI−/− and KtyII−/−K8 mice demonstrates that absence of KIF causes dysregulation of many CE constituents, including downregulation of desmoglein 1. Despite persistence of loricrin expression and upregulation of many Nrf2 targets, including CE components Sprr2d and Sprr2h, extensive barrier defects persist, identifying keratins as essential CE scaffolds. Furthermore, we show that KIFs control mitochondrial lipid composition and activity in a cell-intrinsic manner. Therefore, our study explains the complexity of keratinopathies accompanied by barrier disorders by linking keratin scaffolds to mitochondria, adhesion, and CE formation.
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Affiliation(s)
- Vinod Kumar
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Jamal-Eddine Bouameur
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Janina Bär
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Robert H Rice
- Department of Environmental Toxicology, University of California, Davis, Davis, CA 95616
| | - Hue-Tran Hornig-Do
- Center for Physiology and Pathophysiology, Institute for Vegetative Physiology, University of Cologne, 50931 Cologne, Germany
| | - Dennis R Roop
- Department of Dermatology, University of Colorado, Denver, CO 80045 Charles C. Gates Center for Regenerative Medicine and Stem Cell Biology, University of Colorado, Denver, CO 80045
| | - Nicole Schwarz
- Institute of Molecular and Cellular Anatomy, Rheinisch-Westfälische Technische Hochschule Aachen University, 52074 Aachen, Germany
| | - Susanne Brodesser
- Center for Physiology and Pathophysiology, Institute for Vegetative Physiology, University of Cologne, 50931 Cologne, Germany Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Medical Faculty, University of Cologne, 50931 Cologne, Germany Center for Molecular Medicine Cologne, 50931 Cologne, Germany
| | - Sören Thiering
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, Rheinisch-Westfälische Technische Hochschule Aachen University, 52074 Aachen, Germany
| | - Rudolf J Wiesner
- Center for Physiology and Pathophysiology, Institute for Vegetative Physiology, University of Cologne, 50931 Cologne, Germany Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Medical Faculty, University of Cologne, 50931 Cologne, Germany Center for Molecular Medicine Cologne, 50931 Cologne, Germany
| | | | - Christina B Brazel
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Sandra Heller
- Center for Biotechnology and Biomedicine, 04103 Leipzig, Germany
| | - Hans Binder
- Interdisciplinary Centre for Bioinformatics, University of Leipzig, 04107 Leipzig, Germany
| | - Henry Löffler-Wirth
- Interdisciplinary Centre for Bioinformatics, University of Leipzig, 04107 Leipzig, Germany
| | - Peter Seibel
- Center for Biotechnology and Biomedicine, 04103 Leipzig, Germany
| | - Thomas M Magin
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
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Djudjaj S, Papasotiriou M, Bülow RD, Wagnerova A, Lindenmeyer MT, Cohen CD, Strnad P, Goumenos DS, Floege J, Boor P. Keratins are novel markers of renal epithelial cell injury. Kidney Int 2016; 89:792-808. [PMID: 26924053 DOI: 10.1016/j.kint.2015.10.015] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 09/25/2015] [Accepted: 10/22/2015] [Indexed: 12/14/2022]
Abstract
Keratins, the intermediate filaments of the epithelial cell cytoskeleton, are up-regulated and post-translationally modified in stress situations. Renal tubular epithelial cell stress is a common finding in progressive kidney diseases, but little is known about keratin expression and phosphorylation. Here, we comprehensively describe keratin expression in healthy and diseased kidneys. In healthy mice, the major renal keratins, K7, K8, K18, and K19, were expressed in the collecting ducts and K8, K18 in the glomerular parietal epithelial cells. Tubular expression of all 4 keratins increased by 20- to 40-fold in 5 different models of renal tubular injury as assessed by immunohistochemistry, Western blot, and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). The up-regulation became significant early after disease induction, increased with disease progression, was found de novo in distal tubules and was accompanied by altered subcellular localization. Phosphorylation of K8 and K18 increased under stress. In humans, injured tubules also exhibited increased keratin expression. Urinary K18 was only detected in mice and patients with tubular cell injury. Keratins labeled glomerular parietal epithelial cells forming crescents in patients and animals. Thus, all 4 major renal keratins are significantly, early, and progressively up-regulated upon tubular injury regardless of the underlying disease and may be novel sensitive markers of renal tubular cell stress.
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Affiliation(s)
- Sonja Djudjaj
- Division of Nephrology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany; Institute of Pathology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany
| | - Marios Papasotiriou
- Division of Nephrology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany; Department of Nephrology, University Hospital of Patras, Patras, Greece
| | - Roman D Bülow
- Institute of Pathology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany
| | - Alexandra Wagnerova
- Institute of Pathology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany; Institute of Molecular Biomedicine, Comenius University, Bratislava, Slovakia
| | - Maja T Lindenmeyer
- Division of Nephrology and Institute of Physiology, University Zürich, Zürich, Switzerland
| | - Clemens D Cohen
- Division of Nephrology and Institute of Physiology, University Zürich, Zürich, Switzerland
| | - Pavel Strnad
- Department of Internal Medicine 3 and Interdisziplinäres Zentrum für Klinische Forschung, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany
| | | | - Jürgen Floege
- Division of Nephrology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany
| | - Peter Boor
- Division of Nephrology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany; Institute of Pathology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany; Institute of Molecular Biomedicine, Comenius University, Bratislava, Slovakia.
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16
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Kussano NR, Leme LO, Guimarães ALS, Franco MM, Dode MAN. Molecular markers for oocyte competence in bovine cumulus cells. Theriogenology 2015; 85:1167-76. [PMID: 26792377 DOI: 10.1016/j.theriogenology.2015.11.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 11/28/2015] [Accepted: 11/30/2015] [Indexed: 12/26/2022]
Abstract
This study aimed to quantify the expression of candidate genes in cumulus cells (CCs) from cumulus-oocyte complexes (COCs) with high and low potential for in vitro development up to the blastocyst stage. First, the effects of individual culture and biopsy on embryo development were evaluated. Individuals cultured using the well of the well system were compared with individuals cultured in 20 μL droplets (microdroplets) and those cultured in groups (control). Blastocyst rates were lower for the individual culture systems (P < 0.05; well of the well = 17.9%, n = 95; microdrop = 26.3%, n = 95) than for the control group (45.0%, n = 209). Second, the effects of biopsy on embryo production were compared between the control and microdroplet cultures, and no effects (P > 0.05) were observed for either group. Finally, the expression profiles of glypican 4 (GPC4), IGF4-binding protein, follicle-stimulating hormonereceptor, growth hormone receptor, epidermal growth factor receptor, fibroblast growth factor 11, solute carrier family 2 member 1, solute carrier family 2 member 3,sprouty homolog 1, versican, and keratin protein 8 in CCs obtained by biopsy were quantified by real-time polymerase chain reaction. Cumulus cells were categorized on the basis of the fates of the COCs: expanded blastocyst, cleaved and arrested, and uncleaved. The GPC4 gene was overexpressed (P = 0.007) in CCs from oocytes that formed embryos compared with those that produced cleaved and arrested embryos. We concluded that individual culture reduced blastocyst production; however, biopsy did not affect embryo development. The profile of GPC4 expression can be used as a marker to distinguish COCs with potential for embryo development from those with limited developmental potential.
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Affiliation(s)
- N R Kussano
- School of Veterinary Medicine, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - L O Leme
- School of Agriculture and Veterinary Medicine, University of Brasilia, Brasília, Distrito Federal, Brazil
| | - A L S Guimarães
- School of Agriculture and Veterinary Medicine, University of Brasilia, Brasília, Distrito Federal, Brazil
| | - M M Franco
- School of Veterinary Medicine, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil; Laboratory of Animal Reproduction, Embrapa-Genetic Resources and Biotechnology, Brasília, Distrito Federal, Brazil
| | - M A N Dode
- School of Agriculture and Veterinary Medicine, University of Brasilia, Brasília, Distrito Federal, Brazil; Laboratory of Animal Reproduction, Embrapa-Genetic Resources and Biotechnology, Brasília, Distrito Federal, Brazil.
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Guldiken N, Zhou Q, Kucukoglu O, Rehm M, Levada K, Gross A, Kwan R, James LP, Trautwein C, Omary MB, Strnad P. Human keratin 8 variants promote mouse acetaminophen hepatotoxicity coupled with c-jun amino-terminal kinase activation and protein adduct formation. Hepatology 2015; 62:876-86. [PMID: 25963979 PMCID: PMC4549164 DOI: 10.1002/hep.27891] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 04/15/2015] [Accepted: 05/03/2015] [Indexed: 12/21/2022]
Abstract
UNLABELLED Keratins 8 and 18 (K8/K18) are the intermediate filaments proteins of simple-type digestive epithelia and provide important cytoprotective function. K8/K18 variants predispose humans to chronic liver disease progression and poor outcomes in acute acetaminophen (APAP)-related liver failure. Given that K8 G62C and R341H/R341C are common K8 variants in European and North American populations, we studied their biological significance using transgenic mice. Mice that overexpress the human K8 variants, R341H or R341C, were generated and used together with previously described mice that overexpress wild-type K8 or K8 G62C. Mice were injected with 600 mg/kg of APAP or underwent bile duct ligation (BDL). Livers were evaluated by microarray analysis, quantitative real-time polymerase chain reaction, immunoblotting, histological and immunological staining, and biochemical assays. Under basal conditions, the K8 G62C/R341H/R341C variant-expressing mice did not show an obvious liver phenotype or altered keratin filament distribution, whereas K8 G62C/R341C animals had aberrant disulphide cross-linked keratins. Animals carrying the K8 variants displayed limited gene expression changes, but had lower nicotinamide N-methyl transferase (NNMT) levels and were predisposed to APAP-induced hepatotoxicity. NNMT represents a novel K8/K18-associated protein that becomes up-regulated after K8/K18 transfection. The more pronounced liver damage was accompanied by increased and prolonged JNK activation; elevated APAP protein adducts; K8 hyperphosphorylation at S74/S432 with enhanced keratin solubility; and prominent pericentral keratin network disruption. No differences in APAP serum levels, glutathione, or adenosine triphosphate levels were noted. BDL resulted in similar liver injury and biliary fibrosis in all mouse genotypes. CONCLUSION Expression of human K8 variants G62C, R341H, or R341C in mice predisposes to acute APAP hepatotoxicity, thereby providing direct evidence for the importance of these variants in human acute liver failure.
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Affiliation(s)
- Nurdan Guldiken
- IZKF and Department of Internal Medicine III, University Hospital Aachen, Germany,Department of Internal Medicine I, University Hospital Ulm, Ulm Germany
| | - Qin Zhou
- Department of Medicine, Palo Alto VA Medical Center, CA; and Stanford University Digestive Disease Center, USA
| | - Ozlem Kucukoglu
- Department of Internal Medicine I, University Hospital Ulm, Ulm Germany
| | - Melanie Rehm
- Department of Internal Medicine I, University Hospital Ulm, Ulm Germany
| | - Kateryna Levada
- IZKF and Department of Internal Medicine III, University Hospital Aachen, Germany
| | - Annika Gross
- IZKF and Department of Internal Medicine III, University Hospital Aachen, Germany
| | - Raymond Kwan
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, and the VA Ann Arbor Health Care System, Ann Arbor, MI, USA
| | - Laura P. James
- Arkansas Children's Hospital Research Institute and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Christian Trautwein
- IZKF and Department of Internal Medicine III, University Hospital Aachen, Germany
| | - M. Bishr Omary
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, and the VA Ann Arbor Health Care System, Ann Arbor, MI, USA
| | - Pavel Strnad
- IZKF and Department of Internal Medicine III, University Hospital Aachen, Germany,Department of Internal Medicine I, University Hospital Ulm, Ulm Germany,To whom correspondence should be addressed. Corresponding author: Pavel Strnad, Department of Internal Medicine III and IZKF, University Hospital Aachen, Pauwelsstraße 30, D-52074 Aachen, Tel.: +49(241) 80-35324, Fax: +49(241) 80-82455,
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18
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Tumor necrosis factor-α confers cardioprotection through ectopic expression of keratins K8 and K18. Nat Med 2015; 21:1076-84. [PMID: 26280121 DOI: 10.1038/nm.3925] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 07/15/2015] [Indexed: 12/18/2022]
Abstract
Tumor necrosis factor-α (TNF-α), one of the major stress-induced proinflammatory cytokines, is upregulated in the heart after tissue injury, and its sustained expression can contribute to the development of heart failure. Whether TNF-α also exerts cytoprotective effects in heart failure is not known. Here we provide evidence for a cardioprotective function of TNF-α in a genetic heart failure model, desmin-deficient mice. The cardioprotective effects of TNF-α are a consequence of nuclear factor-κB (NF-κB)-mediated ectopic expression in cardiomyocytes of keratin 8 (K8) and keratin 18 (K18), two epithelial-specific intermediate filament proteins. In cardiomyocytes, K8 and K18 (K8/K18) formed an alternative cytoskeletal network that localized mainly at intercalated discs (IDs) and conferred cardioprotection by maintaining normal ID structure and mitochondrial integrity and function. Ectopic induction of K8/K18 expression in cardiomyocytes also occurred in other genetic and experimental models of heart failure. Loss of the K8/K18 network resulted in a maladaptive cardiac phenotype following transverse aortic constriction. In human failing myocardium, where TNF-α expression is upregulated, K8/K18 were also ectopically expressed and localized primarily at IDs, which did not contain detectable amounts of desmin. Thus, TNF-α- and NF-κB-mediated formation of an alternative, stress-induced intermediate filament cytoskeleton has cardioprotective function in mice and potentially in humans.
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Szabo S, Wögenstein KL, Österreicher CH, Guldiken N, Chen Y, Doler C, Wiche G, Boor P, Haybaeck J, Strnad P, Fuchs P. Epiplakin attenuates experimental mouse liver injury by chaperoning keratin reorganization. J Hepatol 2015; 62:1357-66. [PMID: 25617501 PMCID: PMC4451473 DOI: 10.1016/j.jhep.2015.01.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 12/08/2014] [Accepted: 01/05/2015] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS Epiplakin is a member of the plakin protein family and exclusively expressed in epithelial tissues where it binds to keratins. Epiplakin-deficient (Eppk1(-/-)) mice displayed no obvious spontaneous phenotype, but their keratinocytes showed a faster keratin network breakdown in response to stress. The role of epiplakin in the stressed liver remained to be elucidated. METHODS Wild-type (WT) and Eppk1(-/-) mice were subjected to common bile duct ligation (CBDL) or fed with a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-containing diet. The importance of epiplakin during keratin reorganization was assessed in primary hepatocytes. RESULTS Our experiments revealed that epiplakin is expressed in hepatocytes and cholangiocytes, and binds to keratin 8 (K8) and K18 via multiple domains. In several liver stress models epiplakin and K8 genes displayed identical expression patterns and transgenic K8 overexpression resulted in elevated hepatic epiplakin levels. After CBDL and DDC treatment, Eppk1(-/-) mice developed a more pronounced liver injury and their livers contained larger amounts of hepatocellular keratin granules, indicating impaired disease-induced keratin network reorganization. In line with these findings, primary Eppk1(-/-) hepatocytes showed increased formation of keratin aggregates after treatment with the phosphatase inhibitor okadaic acid, a phenotype which was rescued by the chemical chaperone trimethylamine N-oxide (TMAO). Finally, transfection experiments revealed that Eppk1(-/-) primary hepatocytes were less able to tolerate forced K8 overexpression and that TMAO treatment rescued this phenotype. CONCLUSION Our data indicate that epiplakin plays a protective role during experimental liver injuries by chaperoning disease-induced keratin reorganization.
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Affiliation(s)
- Sandra Szabo
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Karl L Wögenstein
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Christoph H Österreicher
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Nurdan Guldiken
- Department of Internal Medicine III and IZKF, University Hospital Aachen, Aachen, Germany
| | - Yu Chen
- Department of Internal Medicine III and IZKF, University Hospital Aachen, Aachen, Germany
| | - Carina Doler
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Gerhard Wiche
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Peter Boor
- Division of Nephrology and Institute of Pathology, RWTH University of Aachen, Aachen, Germany
| | | | - Pavel Strnad
- Department of Internal Medicine III and IZKF, University Hospital Aachen, Aachen, Germany
| | - Peter Fuchs
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria.
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Guldiken N, Usachov V, Levada K, Trautwein C, Ziol M, Nahon P, Strnad P. Keratins 8 and 18 are type II acute-phase responsive genes overexpressed in human liver disease. Liver Int 2015; 35:1203-12. [PMID: 24930437 DOI: 10.1111/liv.12608] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 05/18/2014] [Indexed: 02/13/2023]
Abstract
BACKGROUND & AIMS Keratins (Ks) 7, 8, 18 and 19 constitute important markers and modifiers of liver disease. In mice, K8 and K18 are stress inducible and a dysregulated K8 > K18 stoichiometry predisposes to formation of Mallory-Denk bodies (MDBs), i.e. aggregates characteristic of chronic liver disorders such as alcoholic liver disease (ALD). In our study, we analyse the expression and the regulation of keratins in context of human liver disease. METHODS K7, K8, K18 and K19 mRNA levels were determined in liver biopsies from patients with ALD, non-alcoholic steatohepatitis (NASH), chronic hepatitis B (HBV), hepatitis C (HCV) and from control subjects. HepG2 and Hep3B cells were treated with IL-1β, IL-6 and TNF-α. Mice were injected with turpentine, an established IL-6 inducer. RESULTS K7, K8 and K18 were 1.5- to 3-fold upregulated in livers of ALD and HCV patients with a more active disease, but not in HBV/NASH subjects, while K19 was significantly elevated in all analysed disorders. K8 and K18 expression displayed a strong correlation (r = 0.89), but dysregulated levels with the K8 > K18 state were seen in ALD. All keratins were overexpressed in subjects with moderate vs. minimal inflammation, while K7, K8 and K18 were upregulated in patients with advanced liver fibrosis. In HepG2/Hep3B cells, IL-6 treatment but not IL-1β or TNF-α significantly increased K8 and K18 expression and elevated K18 levels were seen after turpentine injection. CONCLUSIONS Keratins represent type II acute-phase responsive genes overexpressed in specific human liver disorders. A K8 > K18 state occurs in ALD and predisposes to MDB formation.
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Affiliation(s)
- Nurdan Guldiken
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany; IZKF and Department of Internal Medicine III, RWTH University Hospital Aachen, Aachen, Germany
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21
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Bunel A, Jorssen E, Merckx E, Leroy J, Bols P, Sirard M. Individual bovine in vitro embryo production and cumulus cell transcriptomic analysis to distinguish cumulus-oocyte complexes with high or low developmental potential. Theriogenology 2015; 83:228-37. [DOI: 10.1016/j.theriogenology.2014.09.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/09/2014] [Accepted: 09/11/2014] [Indexed: 01/01/2023]
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22
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Honma Y, Harada M. New therapeutic strategy for hepatocellular carcinoma by molecular targeting agents via inhibition of cellular stress defense mechanisms. J UOEH 2014; 36:229-235. [PMID: 25501753 DOI: 10.7888/juoeh.36.229] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The prognosis of advanced hepatocellular carcinoma (HCC) has remained very poor.It has recently been reported that the molecular targeting agent sorafenib can improve the prognosis of patients with advanced HCC. However, the detailed mechanisms of sorafenib, especially its direct effects on hepatoma and hepatocyte cells, are poorly understood, making a more detailed investigation about the molecular mechanism of sorafenib necessary. Endoplasmic reticulum (ER) stress is related to the pathophysiology of various liver diseases, including chronic viral hepatitis, alcoholic and nonalcoholic steatohepatitis and HCC. In this regard, our recent data examining the molecular effects of sorafenib focused on the cellular defense mechanisms from ER stress, the unfolded protein response (UPR) and keratin phosphorylation, demonstrated that sorafenib inhibited both important cytoprotective mechanisms, UPR and keratin phosphorylation, and enhances the anti-tumor effect in combination with proteasome inhibitors. This review summarizes the cytoprotective mechanisms from ER stress and our results about the direct effect of sorafenib on the cytoprotective mechanisms.
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Affiliation(s)
- Yuichi Honma
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Japan
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23
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Kucukoglu O, Guldiken N, Chen Y, Usachov V, El-Heliebi A, Haybaeck J, Denk H, Trautwein C, Strnad P. High-fat diet triggers Mallory-Denk body formation through misfolding and crosslinking of excess keratin 8. Hepatology 2014; 60:169-78. [PMID: 24519272 DOI: 10.1002/hep.27068] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 02/06/2014] [Indexed: 01/11/2023]
Abstract
UNLABELLED Mallory-Denk bodies (MDBs) are protein aggregates consisting of ubiquitinated keratins 8/18 (K8/K18). MDBs are characteristic of alcoholic and nonalcoholic steatohepatitis (NASH) and discriminate between the relatively benign simple steatosis and the more aggressive NASH. Given the emerging evidence for a genetic predisposition to MDB formation and NASH development in general, we studied whether high-fat (HF) diet triggers MDB formation and liver injury in susceptible animals. Mice were fed a high-fat (HF) or low-fat (LF) diet plus a cofactor for MDB development, 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). Additionally, we fed nontransgenic and K8 overexpressing mice (K8tg) with the HF diet. The presence of MDB and extent of liver injury was evaluated using biochemical markers, histological staining, and immunofluorescence microscopy. In DDC-fed animals, an HF diet resulted in greater liver injury and up-regulation of inflammation-related genes. As a potential mechanism, K8/K18 accumulation and increased ecto-5'-nucleotidase (CD73) levels were noted. In the genetically susceptible K8tg mice, HF diet triggered hepatocellular injury, ballooning, apoptosis, inflammation, and MDB development by way of 1) decreased expression of the major stress-inducible chaperone Hsp72 with appearance of misfolded keratins; 2) elevated levels of the transglutaminase 2 (TG2); 3) increased K8 phosphorylation at S74 with subsequent TG2-mediated crosslinking of phosphorylated K8; and 4) higher production of the MDB-modifier gene CD73. CONCLUSION Our data demonstrate that HF diet triggers aggregate formation and development of liver injury in susceptible individuals through misfolding and crosslinking of excess K8.
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Affiliation(s)
- Ozlem Kucukoglu
- Department of Internal Medicine I, Center for Internal Medicine, University Medical Center Ulm, Ulm, Germany
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24
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Strnad P, Nuraldeen R, Guldiken N, Hartmann D, Mahajan V, Denk H, Haybaeck J. Broad Spectrum of Hepatocyte Inclusions in Humans, Animals, and Experimental Models. Compr Physiol 2013; 3:1393-436. [DOI: 10.1002/cphy.c120032] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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25
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Kröger C, Loschke F, Schwarz N, Windoffer R, Leube RE, Magin TM. Keratins control intercellular adhesion involving PKC-α-mediated desmoplakin phosphorylation. ACTA ACUST UNITED AC 2013; 201:681-92. [PMID: 23690176 PMCID: PMC3664716 DOI: 10.1083/jcb.201208162] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Keratins limit PKC-α phosphorylation activity and desmosome turnover to ensure the stability of epithelial intracellular adhesion. Maintenance of epithelial cell adhesion is crucial for epidermal morphogenesis and homeostasis and relies predominantly on the interaction of keratins with desmosomes. Although the importance of desmosomes to epidermal coherence and keratin organization is well established, the significance of keratins in desmosome organization has not been fully resolved. Here, we report that keratinocytes lacking all keratins show elevated, PKC-α–mediated desmoplakin phosphorylation and subsequent destabilization of desmosomes. We find that PKC-α activity is regulated by Rack1–keratin interaction. Without keratins, desmosomes assemble but are endocytosed at accelerated rates, rendering epithelial sheets highly susceptible to mechanical stress. Re-expression of the keratin pair K5/14, inhibition of PKC-α activity, or blocking of endocytosis reconstituted both desmosome localization at the plasma membrane and epithelial adhesion. Our findings identify a hitherto unknown mechanism by which keratins control intercellular adhesion, with potential implications for tumor invasion and keratinopathies, settings in which diminished cell adhesion facilitates tissue fragility and neoplastic growth.
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Affiliation(s)
- Cornelia Kröger
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
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26
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Snider NT, Leonard JM, Kwan R, Griggs NW, Rui L, Omary MB. Glucose and SIRT2 reciprocally mediate the regulation of keratin 8 by lysine acetylation. ACTA ACUST UNITED AC 2013; 200:241-7. [PMID: 23358244 PMCID: PMC3563689 DOI: 10.1083/jcb.201209028] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Keratin 8 lysine acetylation, which is enhanced by hyperglycemia and reduced by SIRT2, alters filament organization and reduces solubility. Lysine acetylation is an important posttranslational modification that regulates microtubules and microfilaments, but its effects on intermediate filament proteins (IFs) are unknown. We investigated the regulation of keratin 8 (K8), a type II simple epithelial IF, by lysine acetylation. K8 was basally acetylated and the highly conserved Lys-207 was a major acetylation site. K8 acetylation regulated filament organization and decreased keratin solubility. Acetylation of K8 was rapidly responsive to changes in glucose levels and was up-regulated in response to nicotinamide adenine dinucleotide (NAD) depletion and in diabetic mouse and human livers. The NAD-dependent deacetylase sirtuin 2 (SIRT2) associated with and deacetylated K8. Pharmacologic or genetic inhibition of SIRT2 decreased K8 solubility and affected filament organization. Inhibition of K8 Lys-207 acetylation resulted in site-specific phosphorylation changes of K8. Therefore, K8 acetylation at Lys-207, a highly conserved residue among type II keratins and other IFs, is up-regulated upon hyperglycemia and down-regulated by SIRT2. Keratin acetylation provides a new mechanism to regulate keratin filaments, possibly via modulating keratin phosphorylation.
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Affiliation(s)
- Natasha T Snider
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Singla A, Moons DS, Snider NT, Wagenmaker ER, Jayasundera VB, Omary MB. Oxidative stress, Nrf2 and keratin up-regulation associate with Mallory-Denk body formation in mouse erythropoietic protoporphyria. Hepatology 2012; 56:322-31. [PMID: 22334478 PMCID: PMC3389581 DOI: 10.1002/hep.25664] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 01/27/2012] [Indexed: 01/02/2023]
Abstract
UNLABELLED Mallory-Denk bodies (MDBs) are hepatocyte inclusions commonly seen in steatohepatitis. They are induced in mice by feeding 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) for 12 weeks, which also causes porphyrin accumulation. Erythropoietic protoporphyria (EPP) is caused by mutations in ferrochelatase (fch), and a fraction of EPP patients develop liver disease that is phenocopied in Fech(m1Pas) mutant (fch/fch) mice, which have an inactivating fch mutation. fch/fch mice develop spontaneous MDBs, but the molecular factors involved in their formation and whether they relate to DDC-induced MDBs are unknown. We tested the hypothesis that fch mutation creates a molecular milieu that mimics experimental drug-induced MDBs. In 13- and 20-week-old fch/fch mice, serum alkaline phosphatase, alanine aminotransferase, and bile acids were increased. The 13-week-old fch/fch mice did not develop histologically evident MDBs but manifested biochemical alterations required for MDB formation, including increased transglutaminase-2 and keratin overexpression, with a greater keratin 8 (K8)-to-keratin 18 (K18) ratio, which are critical for drug-induced MDB formation. In 20-week-old fch/fch mice, spontaneous MDBs were readily detected histologically and biochemically. Short-term (3-week) DDC feeding markedly induced MDB formation in 20-week-old fch/fch mice. Under basal conditions, old fch/fch mice had significant alterations in mitochondrial oxidative-stress markers, including increased protein oxidation, decreased proteasomal activity, reduced adenosine triphosphate content, and Nrf2 (redox sensitive transcription factor) up-regulation. Nrf2 knockdown in HepG2 cells down-regulated K8, but not K18. CONCLUSION Fch/fch mice develop age-associated spontaneous MDBs, with a marked propensity for rapid MDB formation upon exposure to DDC, and therefore provide a genetic model for MDB formation. Inclusion formation in the fch/fch mice involves oxidative stress which, together with Nrf2-mediated increase in K8, promotes MDB formation.
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Affiliation(s)
- Amika Singla
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-5622
| | - David S. Moons
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109-5622
| | - Natasha T. Snider
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-5622
| | - Elizabeth R. Wagenmaker
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-5622
| | - V. Bernadene Jayasundera
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-5622
| | - M. Bishr Omary
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-5622,Department of Medicine, University of Michigan Medical School, Ann Arbor, MI 48109-5622,To whom correspondence should be addressed: Bishr Omary, University of Michigan Medical School, Department of Molecular & Integrative Physiology, 7744 Medical Science Building II, 1137 Catherine St., Ann Arbor, MI 48109, Phone: 734-764-4376, Fax: 734-936-8813,
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Genetic background effects of keratin 8 and 18 in a DDC-induced hepatotoxicity and Mallory-Denk body formation mouse model. J Transl Med 2012; 92:857-67. [PMID: 22449798 DOI: 10.1038/labinvest.2012.49] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Keratin 8 (K8) and keratin 18 (K18) form the major hepatocyte cytoskeleton. We investigated the impact of genetic loss of either K8 or K18 on liver homeostasis under toxic stress with the hypothesis that K8 and K18 exert different functions. krt8⁻/⁻ and krt18⁻/⁻ mice crossed into the same 129-ola genetic background were treated by acute and chronic administration of 3,5-diethoxy-carbonyl-1,4-dihydrocollidine (DDC). In acutely DDC-intoxicated mice, macrovesicular steatosis was more pronounced in krt8⁻/⁻ and krt18⁻/⁻ compared with wild-type (wt) animals. Mallory-Denk bodies (MDBs) appeared in krt18⁻/⁻ mice already at an early stage of intoxication in contrast to krt8⁻/⁻ mice that did not display MDB formation when fed with DDC. Keratin-deficient mice displayed significantly lower numbers of apoptotic hepatocytes than wt animals. krt8⁻/⁻, krt18⁻/⁻ and control mice displayed comparable cell proliferation rates. Chronically DDC-intoxicated krt18⁻/⁻ and wt mice showed a similarly increased degree of steatohepatitis with hepatocyte ballooning and MDB formation. In krt8⁻/⁻ mice, steatosis was less, ballooning, and MDBs were absent. krt18⁻/⁻ mice developed MDBs whereas krt8⁻/⁻ mice on the same genetic background did not, highlighting the significance of different structural properties of keratins. They are independent of the genetic background as an intrinsic factor. By contrast, toxicity effects may depend on the genetic background. krt8⁻/⁻ and krt18⁻/⁻ mice on the same genetic background show similar sensitivity to DDC intoxication and almost resemble wt animals regarding survival, degree of porphyria, liver-to-body weight ratio, serum bilirubin and liver enzyme levels. This stands in contrast to previous work where krt8⁻/⁻ and krt18⁻/⁻ mice on different genetic backgrounds were investigated.
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Hanada S, Harada M, Abe M, Akiba J, Sakata M, Kwan R, Taniguchi E, Kawaguchi T, Koga H, Nagata E, Ueno T, Sata M. Aging modulates susceptibility to mouse liver Mallory-Denk body formation. J Histochem Cytochem 2012; 60:475-83. [PMID: 22473941 DOI: 10.1369/0022155412441478] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mallory-Denk bodies (MDBs) are hepatocyte cytoplasmic inclusions found in several liver diseases and consist primarily of the cytoskeletal proteins, keratins 8 and 18 (K8/K18). Recent evidence indicates that the extent of stress-induced protein misfolding, a K8>K18 overexpression state, and transglutaminase-2 activation promote MDB formation. In addition, the genetic background and gender play an important role in mouse MDB formation, but the effect of aging on this process is unknown. Given that oxidative stress increases with aging, the authors hypothesized that aging predisposes to MDB formation. They used an established mouse MDB model-namely, feeding non-transgenic male FVB/N mice (1, 3, and 8 months old) with 3,5 diethoxycarbonyl-1,4-dihydrocollidine for 2 months. MDB formation was assessed using immunofluorescence staining and biochemically by demonstrating keratin and ubiquitin-containing crosslinks generated by transglutaminase-2. Immunofluorescence staining showed that old mice had a significant increase in MDB formation compared with young mice. MDB formation paralleled the generation of high molecular weight ubiquitinated keratin-containing complexes and induction of p62. Old mouse livers had increased oxidative stress. In addition, 20S proteasome activity and autophagy were decreased, and endoplasmic reticulum stress was increased in older livers. Therefore, aging predisposes to experimental MDB formation, possibly by decreased activity of protein degradation machinery.
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Affiliation(s)
- Shinichiro Hanada
- Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan.
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Österreicher CH, Trauner M. Xenobiotic-induced liver injury and fibrosis. Expert Opin Drug Metab Toxicol 2012; 8:571-80. [PMID: 22452290 DOI: 10.1517/17425255.2012.674511] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Many different drugs and xenobiotics (chemical compounds foreign to an organism) can injure the bile duct epithelium and cause inflammatory bile duct diseases (cholangiopathies) ranging from transient cholestasis to vanishing bile duct syndrome, sclerosing cholangitis with development of biliary fibrosis and cirrhosis. Animal models of xenobiotic-induced liver injury have provided major mechanistic insights into the molecular mechanisms of xenobiotic-induced cholangiopathies and biliary fibrosis including primary biliary cirrhosis and primary sclerosing cholangitis. AREAS COVERED In this review, the authors discuss the basic principles of xenobiotic-induced liver and bile duct injury and biliary fibrosis with emphasis on animal models. A PubMed search was performed using the search terms "xenobiotic," "liver injury," "cholestasis," and "biliary fibrosis." Reference lists of retrieved articles were also searched for relevant literature. EXPERT OPINION Xenobiotic-induced cholangiopathies are underestimated and frequently overlooked medical conditions due to their often transient nature. However, biliary disease may progress to vanishing bile duct syndrome, biliary fibrosis, and cirrhosis. Moreover, xenobiotics may prime the liver for subsequent liver disease by other agents and may also contribute to the development of hepatobiliary cancer though interaction with resident stem cells.
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Affiliation(s)
- Christoph H Österreicher
- Medical University of Vienna, Institute of Pharmacology, Center for Physiology and Pharmacology, Vienna, Austria
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Kwan R, Hanada S, Harada M, Strnad P, Li DH, Omary MB. Keratin 8 phosphorylation regulates its transamidation and hepatocyte Mallory-Denk body formation. FASEB J 2012; 26:2318-26. [PMID: 22362895 DOI: 10.1096/fj.11-198580] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mallory-Denk bodies (MDBs) are hepatocyte inclusions that are associated with poor liver disease prognosis. The intermediate filament protein keratin 8 (K8) and its cross-linking by transglutaminase-2 (TG2) are essential for MDB formation. K8 hyperphosphorylation occurs in association with liver injury and MDB formation, but the link between keratin phosphorylation and MDB formation is unknown. We used a mutational approach to identify K8 Q70 as a residue that is important for K8 cross-linking to itself and other liver proteins. K8 cross-linking is markedly enhanced on treating cells with a phosphatase inhibitor and decreases dramatically on K8 S74A or Q70N mutation in the presence of phosphatase inhibition. K8 Q70 cross-linking, in the context of synthetic peptides or intact proteins transfected into cells, is promoted by phosphorylation at K8 S74 or by an S74D substitution and is inhibited by S74A mutation. Transgenic mice that express K8 S74A or a K8 G62C liver disease variant that inhibits K8 S74 phosphorylation have a markedly reduced ability to form MDBs. Our findings support a model in which the stress-triggered phosphorylation of K8 S74 induces K8 cross-linking by TG2, leading to MDB formation. These findings may extend to neuropathies and myopathies that are characterized by intermediate filament-containing inclusions.
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Affiliation(s)
- Raymond Kwan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0622, USA.
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Delavalle PY, Alsaleh K, Pillez A, Cocquerel L, Allet C, Dumont P, Loyens A, Leteurtre E, Omary MB, Dubuisson J, Rouillé Y, Wychowski C. Hepatocyte-derived cultured cells with unusual cytoplasmic keratin-rich spheroid bodies. Exp Cell Res 2011; 317:2683-94. [PMID: 21907707 DOI: 10.1016/j.yexcr.2011.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 08/22/2011] [Accepted: 08/24/2011] [Indexed: 10/17/2022]
Abstract
Cytoplasmic inclusions are found in a variety of diseases that are characteristic morphological features of several hepatic, muscular and neurodegenerative disorders. They display a predominantly filamentous ultrastructure that is also observed in malignant rhabdoid tumor (MRT). A cellular clone containing an intracytoplasmic body was isolated from hepatocyte cell culture, and in the present study we examined whether this body might be related or not to Mallory-Denk body (MDB), a well characterized intracytoplasmic inclusion, or whether this cellular clone was constituted by malignant rhabdoid tumor cells. The intracytoplasmic body was observed in electron microscopy (EM), confocal immunofluorescence microscopy and several proteins involved in the formation of its structure were identified. Using light microscopy, a spheroid body (SB) described as a single regular-shaped cytoplasmic body was observed in cells. During cytokinesis, the SB was disassembled and reassembled in a way to reconstitute a unique SB in each progeny cell. EM examination revealed that the SB was not surrounded by a limiting membrane. However, cytoplasmic filaments were concentrated in a whorled array. These proteins were identified as keratins 8 and 18 (K8/K18), which formed the central core of the SB surrounded by a vimentin cage-like structure. This structure was not related to Mallory-Denk body or aggresome since no aggregated proteins were located in SB. Moreover, the structure of SB was not due to mutations in the primary sequence of K8/K18 and vimentin since no difference was observed in the mRNA sequence of their genes, isolated from Huh-7 and Huh-7w7.3 cells. These data suggested that cellular factor(s) could be responsible for the SB formation process. Aggregates of K18 were relocated in the SB when a mutant of K18 inducing disruption of K8/K18 IF network was expressed in the cellular clone. Furthermore, the INI1 protein, a remodeling-chromatin factor deficient in rhabdoid cells, which contain a spheroid perinuclear inclusion body, was found in our cellular clone. In conclusion, our data suggest that Huh-7w7.3 cells constitute an excellent model for determining the cellular factor(s) involved in the process of spheroid perinuclear body formation.
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Mahajan V, Klingstedt T, Simon R, Nilsson KPR, Thueringer A, Kashofer K, Haybaeck J, Denk H, Abuja PM, Zatloukal K. Cross β-sheet conformation of keratin 8 is a specific feature of Mallory-Denk bodies compared with other hepatocyte inclusions. Gastroenterology 2011; 141:1080-1090.e1-7. [PMID: 21699779 DOI: 10.1053/j.gastro.2011.05.039] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 05/09/2011] [Accepted: 05/20/2011] [Indexed: 01/18/2023]
Abstract
BACKGROUND & AIMS Mallory-Denk bodies (MDBs) are cytoplasmic protein aggregates in hepatocytes in steatohepatitis and other liver diseases. We investigated the molecular structure of keratin 8 (K8) and 18 (K18), sequestosome 1/p62, and ubiquitin, which are the major constituents of MDBs, to investigate their formation and role in disease pathogenesis. METHODS Luminescent conjugated oligothiophenes (LCOs), h-HTAA, and p-FTAA are fluorescent amyloid ligands that specifically bind proteins with cross β-sheet conformation. We used LCOs to investigate conformational changes in MDBs in situ in human and murine livers as well as in transfection studies. RESULTS LCO analysis showed cross β-sheet conformation in human MDBs from patients with alcoholic and nonalcoholic steatohepatitis or hepatocellular carcinoma, but not in intracellular hyaline bodies, α₁-antitrypsin deficiency, or ground-glass inclusions. LCOs bound to MDBs induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine feeding of mice at all developmental stages. CHO-K1 cells transfected with various combinations of SQSTM1/p62, ubi, and Krt8/Krt18 showed that K8 was more likely to have cross β-sheet conformation than K18, whereas p62 never had cross β-sheet conformation. The different conformational properties of K8 and K18 were also shown by circular dichroism analysis. CONCLUSIONS K8 can undergo conformational changes from predominantly α-helical to cross β-sheet, which would allow it to form MDBs. These findings might account for the observation that krt8⁻/⁻ mice do not form MDBs, whereas its excess facilitates MDB formation. LCOs might be used in diagnosis of liver disorders; they can be applied to formalin-fixed, paraffin-embedded tissues to characterize protein aggregates in liver cells.
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Affiliation(s)
- Vineet Mahajan
- Institute of Pathology, Medical University of Graz, Graz, Austria
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Molnar A, Haybaeck J, Lackner C, Strnad P. The cytoskeleton in nonalcoholic steatohepatitis: 100 years old but still youthful. Expert Rev Gastroenterol Hepatol 2011; 5:167-77. [PMID: 21476912 DOI: 10.1586/egh.11.5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The hepatocellular cytoskeleton consists of three filamentous systems: microfilaments, microtubules and keratins (Ks). While the alterations in microfilaments and microtubules during nonalcoholic steatohepatitis (NASH) are largely unexplored, K8/K18 reorganization into Mallory-Denk bodies (MDBs) represents a NASH hallmark, and serological K18 fragments constitute an established tool to monitor NASH severity. To commemorate the 100th anniversary of the first description of MDBs, this article summarizes the composition and function of the hepatocellular cytoskeleton, as well as the importance of cytoskeletal alterations in NASH. The significance of MDBs in clinical routine is illustrated, as are the findings from MDB mouse models, which shape our current view of MDB pathogenesis. Even after 100 years, the cytoskeleton represents a fascinating but greatly understudied area of NASH biology.
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Affiliation(s)
- Agnes Molnar
- Department of Internal Medicine I, University Hospital Ulm, Germany
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Absence of keratin 8 confers a paradoxical microflora-dependent resistance to apoptosis in the colon. Proc Natl Acad Sci U S A 2011; 108:1445-50. [PMID: 21220329 DOI: 10.1073/pnas.1010833108] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Keratin 8 (K8) is a major intermediate filament protein present in enterocytes and serves an antiapoptotic function in hepatocytes. K8-null mice develop colonic hyperplasia and colitis that are reversed after antibiotic treatment. To investigate the pathways that underlie the mechanism of colonocyte hyperplasia and the normalization of the colonic phenotype in response to antibiotics, we performed genome-wide microarray analysis. Functional annotation of genes that are differentially regulated in K8(-/-) and K8(+/+) isolated colon crypts (colonocytes) identified apoptosis as a major altered pathway. Exposure of K8(-/-) colonocytes or colon organ ("organoid") cultures, but not K8(-/-) small intestine organoid cultures, to apoptotic stimuli showed, surprisingly, that they are resistant to apoptosis compared with their wild-type counterparts. This resistance is not related to inflammation per se because T-cell receptor α-null (TCR-α(-/-)) and wild-type colon cultures respond similarly upon induction of apoptosis. Following antibiotic treatment, K8(-/-) colonocytes and organ cultures become less resistant to apoptosis and respond similarly to the wild-type colonocytes. Antibiotics also normalize most differentially up-regulated genes, including survivin and β4-integrin. Treatment of K8(-/-) mice with anti-β4-integrin antibody up-regulated survivin, and induced phosphorylation of focal adhesion kinase with decreased activation of caspases. Therefore, unlike the proapoptotic effect of K8 mutation or absence in hepatocytes, lack of K8 confers resistance to colonocyte apoptosis in a microflora-dependent manner.
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Aishima S, Fujita N, Mano Y, Iguchi T, Taketomi A, Maehara Y, Oda Y, Tsuneyoshi M. p62+ Hyaline inclusions in intrahepatic cholangiocarcinoma associated with viral hepatitis or alcoholic liver disease. Am J Clin Pathol 2010; 134:457-65. [PMID: 20716803 DOI: 10.1309/ajcp53yvvjcndzir] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mallory bodies (MBs) and hyaline globules (HGs) are recognized as hepatocellular cytoplasmic inclusions in liver diseases. We reviewed 123 intrahepatic cholangiocarcinomas (ICCs) and encountered 16 cases (13.0%) in which cancer cells had MB-type inclusions and/or HG-type inclusions, both of which are positive for p62 and ubiquitin. The HG type was present in all 16 cases, and 5 cases contained the MB type. Of 16 patients, 12 had chronic liver disease that was related to alcoholic abuse in 4, hepatitis B surface antigen-positive in 3, and hepatitis C virus antibody-positive in 8. Viral infection and liver cirrhosis were more common in ICCs with p62+ inclusions (P = .0004 and P = .0199, respectively). Of 16 ICCs, 15 with hyaline inclusions had a peripheral tumor location (P = .0052). On ultrastructural examination, the MB type had an electron-dense fibrillar appearance, while the HG type appeared as rounded masses of granular materials. Our results suggest that intracytoplasmic hyaline bodies occasionally can be found in cholangiocarcinoma with chronic liver disease related to viral hepatitis or alcoholic intake.
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Hanada S, Snider NT, Brunt EM, Hollenberg PF, Omary MB. Gender dimorphic formation of mouse Mallory-Denk bodies and the role of xenobiotic metabolism and oxidative stress. Gastroenterology 2010; 138:1607-17. [PMID: 20064513 PMCID: PMC2847059 DOI: 10.1053/j.gastro.2009.12.055] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 12/14/2009] [Accepted: 12/28/2009] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS Mallory-Denk bodies (MDBs) are keratin (K)-rich cytoplasmic hepatocyte inclusions commonly associated with alcoholic steatohepatitis. Given the significant gender differences in predisposition to human alcohol-related liver injury, and the strain difference in mouse MDB formation, we hypothesized that sex affects MDB formation. METHODS MDBs were induced in male and female mice overexpressing K8, which are predisposed to MDB formation, and in nontransgenic mice by feeding the porphyrinogenic compound 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). MDB presence was determined by histologic, immunofluorescence, and biochemical analyses and correlated to liver injury using serologic and pathologic markers. Cytoskeletal and metabolic liver protein analysis, in vitro metabolism studies, and measurement of oxidative stress markers and protoporphyrin-IX were performed. RESULTS Male mice formed significantly more MDBs, which was attenuated modestly by estradiol. MDB formation was accompanied by increased oxidative stress. Female mice had significantly fewer MDBs and oxidative stress-related changes, but had increased ductular reaction protoporphyrin-IX accumulation, and MDB-preventive K18 induction. Evaluation of the microsomal cytochrome-P450 (CYP) enzymes revealed significant gender differences in protein expression and activity in untreated and DDC-fed mice, and showed that DDC is metabolized by CYP3A. The changes in CYPs account for the gender differences in porphyria and DDC metabolism. DDC metabolite formation and oxidative injury accumulate on chronic DDC exposure in males, despite more efficient acute metabolism in females. CONCLUSIONS Gender dimorphic formation of MDBs and porphyria associate with differences in CYPs, oxidative injury, and selective keratin induction. These findings may extend to human MDBs and other neuropathy- and myopathy-related inclusions.
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Affiliation(s)
- Shinichiro Hanada
- Departments of Molecular & Integrative Physiology, Medicine, University of Michigan School of Medicine, Ann Arbor, MI 48109–5622, Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume 830–0011, Japan
| | - Natasha T. Snider
- Departments of Molecular & Integrative Physiology, Medicine, University of Michigan School of Medicine, Ann Arbor, MI 48109–5622,To whom correspondence should be addressed: Natasha Snider, University of Michigan School of Medicine, Department of Molecular & Integrative Physiology, 7720 Medical Science II, 1301 E. Catherine Street, Ann Arbor, MI 48109-5622, (734) 647-6461 Phone; (734) 936-8813 Fax,
| | - Elizabeth M. Brunt
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Paul F. Hollenberg
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, MI 48109–5622
| | - M. Bishr Omary
- Departments of Molecular & Integrative Physiology, Medicine, University of Michigan School of Medicine, Ann Arbor, MI 48109–5622
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Autophagy is involved in the elimination of intracellular inclusions, Mallory-Denk bodies, in hepatocytes. Med Mol Morphol 2010; 43:13-8. [PMID: 20340001 DOI: 10.1007/s00795-009-0476-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Accepted: 09/28/2009] [Indexed: 12/19/2022]
Abstract
Several human liver diseases are associated with formation of hepatocyte Mallory-Denk bodies (MDB) composed of keratins and ubiquitin. Similar inclusions are found in various other diseases, neurodegenerative and muscle disorders. However, the mechanisms of MDB formation have been unclear. Autophagy is a degradation process of intracellular proteins and organelles. In the present study we examined the association of autophagy with the formation of MDB. We fed wild-type and keratin 8-transgenic mice with a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-containing diet for 9 days. The livers were analyzed by immunohistochemistry and conventional and immune electron microscopy. Short-term DDC feeding induced MDB in keratin 8-transgenic but not in nontransgenic mouse livers. Electron microscopy revealed inclusions composed of electron-dense materials and filaments in hepatocyte cytoplasm and many autophagolysosomes in hepatocytes. Inclusions were positive for keratin 8/18 and ubiquitin examined by immunoelectron microscopy. Gold particles for keratin 8/18 or ubiquitin were found in the autophagic vacuoles near or in the inclusions. Keratin 8 overexpression accelerates MDB formation, and the keratin 8-transgenic mouse is a useful tool for the study of MDB formation. Autophagy apparently participates in the elimination of components of MDB. Manipulation of autophagy may be a possible therapeutic strategy for various inclusion-associated diseases.
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Fortier AM, Van Themsche C, Asselin E, Cadrin M. Akt isoforms regulate intermediate filament protein levels in epithelial carcinoma cells. FEBS Lett 2010; 584:984-8. [PMID: 20109457 DOI: 10.1016/j.febslet.2010.01.045] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 12/11/2009] [Accepted: 01/11/2010] [Indexed: 11/16/2022]
Abstract
Keratin 8 and 18 are simple epithelial intermediate filament (IF) proteins, whose expression is differentiation- and tissue-specific, and is maintained during tumorigenesis. Vimentin IF is often co-expressed with keratins in cancer cells. Recently, IF have been proposed to be involved in signaling pathways regulating cell growth, death and motility. The PI3K/Akt pathway plays a pivotal role in these processes. Thus, we investigated the role of Akt (1 and 2) in regulating IF expression in different epithelial cancer cell lines. Over-expression of Akt1 increases K8/18 proteins. Akt2 up-regulates K18 and vimentin expression by an increased mRNA stability. To our knowledge, these results represent the first indication that Akt isoforms regulate IF expression and support the hypothesis that IFs are involved in PI3K/Akt pathway.
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Affiliation(s)
- Anne-Marie Fortier
- Department of Chemistry-Biology, University of Quebec at Trois-Rivieres, Trois-Rivieres, Quebec, Canada G9A 5H7
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Omary MB, Ku NO, Strnad P, Hanada S. Toward unraveling the complexity of simple epithelial keratins in human disease. J Clin Invest 2009; 119:1794-805. [PMID: 19587454 DOI: 10.1172/jci37762] [Citation(s) in RCA: 204] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Simple epithelial keratins (SEKs) are found primarily in single-layered simple epithelia and include keratin 7 (K7), K8, K18-K20, and K23. Genetically engineered mice that lack SEKs or overexpress mutant SEKs have helped illuminate several keratin functions and served as important disease models. Insight into the contribution of SEKs to human disease has indicated that K8 and K18 are the major constituents of Mallory-Denk bodies, hepatic inclusions associated with several liver diseases, and are essential for inclusion formation. Furthermore, mutations in the genes encoding K8, K18, and K19 predispose individuals to a variety of liver diseases. Hence, as we discuss here, the SEK cytoskeleton is involved in the orchestration of several important cellular functions and contributes to the pathogenesis of human liver disease.
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Affiliation(s)
- M Bishr Omary
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Hirano K, Guhl B, Roth J, Ziak M. A cell culture system for the induction of Mallory bodies: Mallory bodies and aggresomes represent different types of inclusion bodies. Histochem Cell Biol 2009; 132:293-304. [DOI: 10.1007/s00418-009-0598-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2009] [Indexed: 12/24/2022]
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The impact of CYP2E1 on the development of alcoholic liver disease as studied in a transgenic mouse model. J Hepatol 2009; 50:572-83. [PMID: 19157621 DOI: 10.1016/j.jhep.2008.10.020] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 10/07/2008] [Accepted: 10/14/2008] [Indexed: 12/19/2022]
Abstract
BACKGROUND/AIMS CYP2E1 metabolizes ethanol, generates reactive oxygen species, and is suggested to be important for development of alcoholic liver disease. The present study aims to evaluate the role of CYP2E1 in combination with ethanol for development of alcoholic liver disease using mice transgenic for the human CYP2E1 gene. METHODS Changes in hepatic gene expression were monitored in controls and mice transgenic for human CYP2E1, treated with ethanol or isocaloric dextrose intragastrically for 4 weeks, and related to pathology using Affymetrix microarrays and TaqMan RealTime PCR. RESULTS Presence of the CYP2E1 transgene increased liver injury and increased expression of stress related genes. Microarray analyses revealed the expression of structural genes, particularly cytokeratin 8 and 18, to be highly related to pathology. CONCLUSIONS This in vivo study confirms several findings regarding CYP2E1 and alcohol previously found only in vitro. These results provide in vivo evidence that CYP2E1 overexpression aggravates hepatic injury, and suggest that expression of cytokeratins 8 and 18 can be considered as biomakers for the progression of alcoholic liver disease.
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Mallory-Denk-bodies: lessons from keratin-containing hepatic inclusion bodies. Biochim Biophys Acta Mol Basis Dis 2008; 1782:764-74. [PMID: 18805482 DOI: 10.1016/j.bbadis.2008.08.008] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 08/25/2008] [Accepted: 08/26/2008] [Indexed: 01/08/2023]
Abstract
Inclusion bodies are characteristic morphological features of various neuronal, muscular and other human disorders. They share common molecular constituents such as p62, chaperones and proteasome subunits. The proteins within aggregates are misfolded with increased beta-sheet structure, they are heavily phosphorylated, ubiquitinylated and partially degraded. Furthermore, involvement of proteasomal system represents a common feature of virtually all inclusions. Multiple aggregates contain intermediate filament proteins as their major constituents. Among them, Mallory-Denk bodies (MDBs) are the best studied. MDBs represent hepatic inclusions observed in diverse chronic liver diseases such as alcoholic and non-alcoholic steatohepatitis, chronic cholestasis, metabolic disorders and hepatocellular neoplasms. MDBs are induced in mice fed griseofulvin or 3,5-diethoxycarbonyl-1,4-dihydrocollidine and resolve after discontinuation of toxin administration. The availability of a drug-induced model makes MDBs a unique tool for studying inclusion formation. Our review summarizes the recent advances gained from this model and shows how they relate to observations in other aggregates. The MDB formation-underlying mechanisms include protein misfolding, chaperone alterations, disproportional protein expression with keratin 8>keratin 18 levels and subsequent keratin 8 crosslinking via transglutaminase. p62 presence is crucial for MDB formation. Proteasome inhibitors precipitate MDB formation, whereas stimulation of autophagy with rapamycin attenuates their formation.
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Hanada S, Strnad P, Brunt EM, Omary MB. The genetic background modulates susceptibility to mouse liver Mallory-Denk body formation and liver injury. Hepatology 2008; 48:943-52. [PMID: 18697208 DOI: 10.1002/hep.22436] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
UNLABELLED Mallory-Denk bodies (MDBs) are hepatocyte inclusions found in several liver diseases and consist primarily of keratins 8 and 18 (K8/K18) and ubiquitin that are cross-linked by transglutaminase-2. We hypothesized that genetic variables contribute to the extent of MDB formation, because not all patients with an MDB-associated liver disease develop inclusions. We tested this hypothesis using five strains of mice (FVB/N, C3H/He, Balb/cAnN, C57BL/6, 129X1/Sv) fed for three months (eight mice per strain) the established MDB-inducing agent 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). MDB formation was compared using hematoxylin-and-eosin staining, or immunofluorescence staining with antibodies to K8/K18/ubiquitin, or biochemically by blotting with antibodies to transglutaminase-2/p62 proteins and to K8/K18/ubiquitin to detect keratin cross-linking. DDC feeding induced MDBs in all mouse strains, but there were dramatic strain differences that quantitatively varied 2.5-fold (P < 0.05). MDB formation correlated with hepatocyte ballooning, and most ballooned hepatocytes had MDBs. Immunofluorescence assessment was far more sensitive than hematoxylin-and-eosin staining in detecting small MDBs, which out-numbered (by approximately 30-fold to 90-fold) but did not parallel their large counterparts. MDB scores partially reflected the biochemical presence of cross-linked keratin-ubiquitin species but not the changes in liver size or injury in response to DDC. The extent of steatosis correlated with the total (large+small) number of MDBs, and there was a limited correlation between large MDBs and acidophil bodies. CONCLUSION Mouse MDB formation has important genetic contributions that do not correlate with the extent of DDC-induced liver injury. If extrapolated to humans, the genetic contributions help explain why some patients develop MDBs whereas others are less likely to do so. Detection and classification of MDBs using MDB-marker-selective staining may offer unique links to specific histological features of DDC-induced liver injury.
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Affiliation(s)
- Shinichiro Hanada
- Department of Medicine, Veterans Administration Palo Alto Health Care System and Stanford University, Palo Alto, CA, USA
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Strnad P, Tao GZ, So P, Lau K, Schilling J, Wei Y, Liao J, Omary MB. "Toxic memory" via chaperone modification is a potential mechanism for rapid Mallory-Denk body reinduction. Hepatology 2008; 48:931-42. [PMID: 18697205 DOI: 10.1002/hep.22430] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
UNLABELLED The cytoplasmic hepatocyte inclusions, Mallory-Denk bodies (MDBs), are characteristic of several liver disorders, including alcoholic and nonalcoholic steatohepatitis. In mice, MDBs can be induced by long-term feeding with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) for 3 to 4 months or rapidly reformed in DDC-induced then recovered mice by DDC refeeding or exposure to a wide range of toxins for only 5 to 7 days. The molecular basis for such a rapid reinduction of MDBs is unknown. We hypothesized that protein changes retained after DDC priming contribute to the rapid MDB reappearance and associate with MDB formation in general terms. Two-dimensional differential-in-gel-electrophoresis coupled with mass spectrometry were used to characterize protein changes in livers from the various treatment groups. The alterations were assessed by real-time reverse-transcription polymerase chain reaction and confirmed by immunoblotting. DDC treatment led to pronounced charged isoform changes in several chaperone families, including Hsp25, 60, 70, GRP58, GRP75, and GRP78, which lasted at least for 1 month after discontinuation of DDC feeding, whereas changes in other proteins normalized during recovery. DDC feeding also resulted in altered expression of Hsp72, GRP75, and Hsp25 and in functional impairment of Hsp60 and Hsp70 as determined using a protein complex formation and release assay. The priming toward rapid MDB reinduction lasts for at least 3 months after DDC discontinuation, but becomes weaker after prolonged recovery. MDB reinduction parallels the rapid increase in p62 and Hsp25 levels as well as keratin 8 cross-linking that is normally associated with MDB formation. CONCLUSION Persistent posttranslational modifications in chaperone proteins, coupled with protein cross-linking and altered chaperone expression and function likely contribute to the "toxic memory" of DDC-primed mice. We hypothesize that similar changes are important contributors to inclusion body formation in several diseases.
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Affiliation(s)
- Pavel Strnad
- Department of Medicine, Palo Alto VA Medical Center, Palo Alto, CA, USA
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46
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Harada M, Hanada S, Toivola DM, Ghori N, Omary MB. Autophagy activation by rapamycin eliminates mouse Mallory-Denk bodies and blocks their proteasome inhibitor-mediated formation. Hepatology 2008; 47:2026-35. [PMID: 18454506 DOI: 10.1002/hep.22294] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
UNLABELLED The proteasomal and lysosomal/autophagy pathways in the liver and other tissues are involved in several biological processes including the degradation of misfolded proteins. Exposure of hepatocyte cell lines to proteasome inhibitors (PIs) results in the formation of inclusions that resemble Mallory-Denk bodies (MDBs). Keratins are essential for MDB formation and keratin 8 (K8)-overexpressing transgenic mice are predisposed to MDB formation. We tested the hypothesis that PIs induce MDBs in vivo and that autophagy participates in MDB turnover. The effect of the PI bortezomib (which is used to treat some malignancies) on MDB formation was tested in K8-overexpressing mice and in cultured cells. Inclusion formation was examined using immune and conventional electron microscopy (EM). Bortezomib induced MDB-like inclusions composed of keratins, ubiquitin, and p62 in cultured cells. Short-term exposure to bortezomib induced similar inclusions in K8-overexpressing but not in nontransgenic mice, without causing liver injury. In bortezomib-treated mice, autophagy was activated in hepatocytes as determined by EM and biochemical analysis. Further activation of autophagy by rapamycin (Rap) decreased the number of inclusions in bortezomib-treated K8 transgenic mice significantly. Rap also led to resorption of spontaneously formed MDBs in aging K8-overexpressing mice. Immune EM demonstrated K8-positive and ubiquitin-positive structures in autophagic vacuoles in the mouse liver. CONCLUSION PIs alone are sufficient to induce MDBs in susceptible animals, while Rap-mediated activation of autophagy prevents MDB formation and causes MDB resorption. These findings suggest that some patients treated with PIs may become predisposed to MDB formation. Autophagy provides a potential cellular mechanism for the resorption of cytoplasmic inclusions.
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Affiliation(s)
- Masaru Harada
- Department of Medicine, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA
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47
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Strnad P, Stumptner C, Zatloukal K, Denk H. Intermediate filament cytoskeleton of the liver in health and disease. Histochem Cell Biol 2008; 129:735-49. [PMID: 18443813 PMCID: PMC2386529 DOI: 10.1007/s00418-008-0431-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2008] [Indexed: 02/06/2023]
Abstract
Intermediate filaments (IFs) represent the largest cytoskeletal gene family comprising approximately 70 genes expressed in tissue specific manner. In addition to scaffolding function, they form complex signaling platforms and interact with various kinases, adaptor, and apoptotic proteins. IFs are established cytoprotectants and IF variants are associated with >30 human diseases. Furthermore, IF-containing inclusion bodies are characteristic features of several neurodegenerative, muscular, and other disorders. Acidic (type I) and basic keratins (type II) build obligatory type I and type II heteropolymers and are expressed in epithelial cells. Adult hepatocytes contain K8 and K18 as their only cytoplasmic IF pair, whereas cholangiocytes express K7 and K19 in addition. K8/K18-deficient animals exhibit a marked susceptibility to various toxic agents and Fas-induced apoptosis. In humans, K8/K18 variants predispose to development of end-stage liver disease and acute liver failure (ALF). K8/K18 variants also associate with development of liver fibrosis in patients with chronic hepatitis C. Mallory-Denk bodies (MDBs) are protein aggregates consisting of ubiquitinated K8/K18, chaperones and sequestosome1/p62 (p62) as their major constituents. MDBs are found in various liver diseases including alcoholic and non-alcoholic steatohepatitis and can be formed in mice by feeding hepatotoxic substances griseofulvin and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). MDBs also arise in cell culture after transfection with K8/K18, ubiquitin, and p62. Major factors that determine MDB formation in vivo are the type of stress (with oxidative stress as a major player), the extent of stress-induced protein misfolding and resulting chaperone, proteasome and autophagy overload, keratin 8 excess, transglutaminase activation with transamidation of keratin 8 and p62 upregulation.
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Affiliation(s)
- P Strnad
- Department of Internal Medicine I, University of Ulm, Robert-Koch-Strabe 8, 89081, Ulm, Germany.
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48
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Strnad P, Tao GZ, Zhou Q, Harada M, Toivola DM, Brunt EM, Omary MB. Keratin mutation predisposes to mouse liver fibrosis and unmasks differential effects of the carbon tetrachloride and thioacetamide models. Gastroenterology 2008; 134:1169-79. [PMID: 18395095 PMCID: PMC2692280 DOI: 10.1053/j.gastro.2008.01.035] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Accepted: 01/04/2008] [Indexed: 01/07/2023]
Abstract
BACKGROUND & AIMS Keratins 8 and 18 (K8/K18) are important hepatoprotective proteins. Animals expressing K8/K18 mutants show a marked susceptibility to acute/subacute liver injury. K8/K18 variants predispose to human end-stage liver disease and associate with fibrosis progression during chronic hepatitis C infection. We sought direct evidence for a keratin mutation-related predisposition to liver fibrosis using transgenic mouse models because the relationship between keratin mutations and cirrhosis is based primarily on human association studies. METHODS Mouse hepatofibrosis was induced by carbon tetrachloride (CCl(4)) or thioacetamide. Nontransgenic mice, or mice that over express either human Arg89-to-Cys (R89C mice) or wild-type K18 (WT mice) were used. The extent of fibrosis was evaluated by quantitative real-time reverse-transcription polymerase chain reaction of fibrosis-related genes, liver hydroxyproline measurement, and Picro-Sirius red staining and collagen immunofluorescence staining. RESULTS Compared with control animals, CCl(4) led to similar liver fibrosis but increased injury in K18 R89C mice. In contrast, thioacetamide caused more severe liver injury and fibrosis in K18 R89C as compared with WT and nontransgenic mice and resulted in increased messenger RNA levels of collagen, tissue inhibitor of metalloproteinase 1, matrix metalloproteinase 2, and matrix metalloproteinase 13. Analysis in nontransgenic mice showed that thioacetamide and CCl(4) have dramatically different molecular expression responses involving cytoskeletal and chaperone proteins. CONCLUSIONS Over expression of K18 R89C predisposes transgenic mice to thioacetamide- but not CCl(4)-induced liver fibrosis. Differences in the keratin mutation-associated fibrosis response among the 2 models raise the hypothesis that keratin variants may preferentially predispose to fibrosis in unique human liver diseases. Findings herein highlight distinct differences in the 2 widely used fibrosis models.
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Affiliation(s)
| | | | | | - Masaru Harada
- Department of Medicine, Kurume University School of Medicine, Kurume 830-0011, Japan
| | | | - Elizabeth M. Brunt
- Department of Pathology and Immunology, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8118, St. Louis, MO 63110
| | - M. Bishr Omary
- Corresponding Author Address: Bishr Omary, Palo Alto VA Medical Center, 3801 Miranda Avenue, Mail code 154J, Palo Alto, CA 94304, Tel: (650) 493-5000, x63140; Fax: (650) 852-3259, E-Mail:
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Toivola DM, Nakamichi I, Strnad P, Michie SA, Ghori N, Harada M, Zeh K, Oshima RG, Baribault H, Omary MB. Keratin overexpression levels correlate with the extent of spontaneous pancreatic injury. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 172:882-92. [PMID: 18349119 DOI: 10.2353/ajpath.2008.070830] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mutation of the adult hepatocyte keratins K8 and K18 predisposes to liver disease. In contrast, exocrine pancreas K8 and K18 are dispensable and are co-expressed with limited levels of membrane-proximal K19 and K20. Overexpression of mutant K18 or genetic ablation of K8 in mouse pancreas is well tolerated whereas overexpression of K8 causes spontaneous chronic pancreatitis. To better understand the effect of exocrine pancreatic keratin overexpression, we compared transgenic mice that overexpress K18, K8, or K8/K18, associated with minimal, modest, or large increases in keratin expression, respectively, with nontransgenic wild-type (WT) mice. Overexpression of the type-II keratin K8 up-regulated type-I keratins K18, K19, and K20 and generated K19/K20-containing neocytoplasmic typical or short filaments; however, overexpression of K18 had no effect on K8 levels. K8- and K18-overexpressing pancreata were histologically similar to WT, whereas K8/K18 pancreata displayed age-enhanced vacuolization and atrophy of the exocrine pancreas and exhibited keratin hyperphosphorylation. Zymogen granules in K8/K18 pancreata were 50% smaller and more dispersed than their normal apical concentration but were twice as numerous as in WT controls. Therefore, modest keratin overexpression has minor effects on the exocrine pancreas whereas significant keratin overexpression alters zymogen granule organization and causes aging-associated exocrine atrophy. Keratin absence or mutation is well tolerated after pancreatic but not liver injury, whereas excessive overexpression is toxic to the pancreas but not the liver when induced under basal conditions.
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Affiliation(s)
- Diana M Toivola
- Department of Medicine, Veterans Administration Palo Alto Health Care System, Palo Alto, CA, USA.
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Stumptner C, Fuchsbichler A, Zatloukal K, Denk H. In vitro production of Mallory bodies and intracellular hyaline bodies: the central role of sequestosome 1/p62. Hepatology 2007; 46:851-60. [PMID: 17685470 DOI: 10.1002/hep.21744] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
UNLABELLED Mallory bodies (MBs) and intracellular hyaline bodies (IHBs) are characteristic hepatocellular inclusions. MBs are hallmarks of steatohepatitis, whereas IHBs have first been detected in hepatocellular carcinoma. MBs and IHBs contain ubiquitin and sequestosome 1/p62 (p62), a stress-inducible adapter protein with affinity to polyubiquitinated proteins. MBs differ from IHBs by their keratin content and morphology. In vitro transfections were undertaken to study under defined conditions MB and IHB formation, their pathogenesis, and relationship. CHO-K1, TIB73, and HeLa cells were transfected with keratin 8, keratin 18, ubiquitin, p62, and p62 lacking the ubiquitin binding domain (p62DeltaUBA) and analyzed by immunofluorescence, immunoelectron microscopy, and immunoblotting. Transfection of p62 complementary deoxyribonucleic acid (cDNA) alone led to cytoplasmic aggregates consisting of filaments mostly arranged in parallel arrays resembling amyloid and type 1 MBs. Transfection of p62 and ubiquitin resulted in globular cytoplasmic aggregates with indistinct fibrillar ultrastructure resembling IHBs. Cotransfection of p62, keratin 8, and ubiquitin was necessary to produce in vitro type 2 MBs-like aggregates consisting of randomly oriented 10- to 15-nm filaments. A similar result was obtained when keratin 8 was replaced by keratin 18. After cotransfection of p62DeltaUBA, keratin 8, and ubiquitin, keratin formed irregular aggregates with electron-dense granular-amorphous ultrastructure (resembling type 3 MBs), whereas p62DeltaUBA remained in diffuse cytoplasmic distribution. CONCLUSION Our studies show that in vitro development of classical type 2 MBs requires overexpression of keratin 8 (or keratin 18), ubiquitin, and p62 containing the ubiquitin binding domain, whereas IHBs result from overexpression of p62 together with ubiquitin without keratin involvement.
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Affiliation(s)
- Conny Stumptner
- Institute of Pathology, Medical University of Graz, Graz, Austria
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