Alterations in Cytoskeleton and Mitochondria in the Development and Reversal of Steatosis in Human HepatocytesSummary
Background & Aims: Alterations in mitochondrial morphology and function and increased oxidative stresses in hepatocytes are well established in nonalcoholic fatty liver disease (NAFLD). Patients can undergo lifestyle changes, especially in earlier NAFLD stages, to reverse disease-induced phe...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-01-01
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| Series: | Cellular and Molecular Gastroenterology and Hepatology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352345X23000541 |
| _version_ | 1827923864046272512 |
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| author | Letao Fan Aslihan Gokaltun Sarah Maggipinto Yoshinori Kitagawa Jeevendra Martyn Heidi Yeh Basak E. Uygun Martin L. Yarmush O. Berk Usta |
| author_facet | Letao Fan Aslihan Gokaltun Sarah Maggipinto Yoshinori Kitagawa Jeevendra Martyn Heidi Yeh Basak E. Uygun Martin L. Yarmush O. Berk Usta |
| author_sort | Letao Fan |
| collection | DOAJ |
| description | Background & Aims: Alterations in mitochondrial morphology and function and increased oxidative stresses in hepatocytes are well established in nonalcoholic fatty liver disease (NAFLD). Patients can undergo lifestyle changes, especially in earlier NAFLD stages, to reverse disease-induced phenotypes on a gross level. Yet, little is known about whether mitochondrial function and injuries recover upon reversal. Thus, we elucidated this question and interplays between the cytoskeletal network and mitochondria in the development and reversal of steatosis. Methods: We cultured primary human hepatocytes stably for 2 weeks and used free fatty acid supplementation to induce steatosis over 7 days and reversed steatosis by free fatty acid withdrawal over the next 7 days. We assessed cytoskeletal and mitochondrial morphologies using immunocytochemistry and confocal microscopy. We evaluated mitochondrial respiration and function via the Seahorse analyzer, in which we fully optimized reagent dosing specifically for human hepatocytes. Results: During early steatosis, intracellular lipid droplets displaced microtubules altering mitochondrial distribution, and disrupted the F-actin network, leading to loss of bile canaliculi in steatotic hepatocytes. Basal mitochondrial respiration, maximum respiratory capacity, and resistance to H2O2-induced cell death also increased as an adaptative response. Upon reversal of steatosis, F-actin and bile canaliculi were restored in hepatocytes. Nevertheless, we observed an increase in elongated mitochondrial branches accompanied by decreases in α-tubulin expression, mitochondrial proton leak, and susceptibility to H2O2-induced cell death. Conclusions: Despite the restoration of cytoskeletons morphologically upon reversal of steatosis, the mitochondria in hepatocytes were impaired owing to early adaptative respiratory increase. Hepatocytes thus were highly predisposed to H2O2-induced cell death. These results indicate the persistence of potential health risks for recovering NAFLD patients. |
| first_indexed | 2024-03-13T05:02:15Z |
| format | Article |
| id | doaj.art-eb0b08a16174407d815dc363b82b8e1b |
| institution | Directory Open Access Journal |
| issn | 2352-345X |
| language | English |
| last_indexed | 2024-03-13T05:02:15Z |
| publishDate | 2023-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Cellular and Molecular Gastroenterology and Hepatology |
| spelling | doaj.art-eb0b08a16174407d815dc363b82b8e1b2023-06-17T05:19:10ZengElsevierCellular and Molecular Gastroenterology and Hepatology2352-345X2023-01-01162243261Alterations in Cytoskeleton and Mitochondria in the Development and Reversal of Steatosis in Human HepatocytesSummaryLetao Fan0Aslihan Gokaltun1Sarah Maggipinto2Yoshinori Kitagawa3Jeevendra Martyn4Heidi Yeh5Basak E. Uygun6Martin L. Yarmush7O. Berk Usta8Center for Engineering in Medicine and Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts; Department of Scientifc Research, Shriners Hospital for Children, Boston, MassachusettsCenter for Engineering in Medicine and Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts; Department of Scientifc Research, Shriners Hospital for Children, Boston, Massachusetts; Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts; Department of Chemical Engineering, Hacettepe University, Beytepe, Ankara, TurkeyCenter for Engineering in Medicine and Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Scientifc Research, Shriners Hospital for Children, Boston, MassachusettsDepartment of Scientifc Research, Shriners Hospital for Children, Boston, Massachusetts; Department of Anesthesiology, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MassachusettsDepartment of Scientifc Research, Shriners Hospital for Children, Boston, Massachusetts; Department of Anesthesiology, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MassachusettsDepartment of Surgery, Massachusetts General Hospital, Boston, MassachusettsCenter for Engineering in Medicine and Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts; Department of Scientifc Research, Shriners Hospital for Children, Boston, MassachusettsCenter for Engineering in Medicine and Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts; Department of Scientifc Research, Shriners Hospital for Children, Boston, Massachusetts; Department of Biomedical Engineering, Rutgers University, Piscataway, New JerseyCenter for Engineering in Medicine and Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts; Department of Scientifc Research, Shriners Hospital for Children, Boston, Massachusetts; Correspondence Address correspondence to: O. Berk Usta, PhD, Department of Surgery, Massachusetts General Hospital, 51 Blossom Street, Boston, Massachusetts 02114.Background & Aims: Alterations in mitochondrial morphology and function and increased oxidative stresses in hepatocytes are well established in nonalcoholic fatty liver disease (NAFLD). Patients can undergo lifestyle changes, especially in earlier NAFLD stages, to reverse disease-induced phenotypes on a gross level. Yet, little is known about whether mitochondrial function and injuries recover upon reversal. Thus, we elucidated this question and interplays between the cytoskeletal network and mitochondria in the development and reversal of steatosis. Methods: We cultured primary human hepatocytes stably for 2 weeks and used free fatty acid supplementation to induce steatosis over 7 days and reversed steatosis by free fatty acid withdrawal over the next 7 days. We assessed cytoskeletal and mitochondrial morphologies using immunocytochemistry and confocal microscopy. We evaluated mitochondrial respiration and function via the Seahorse analyzer, in which we fully optimized reagent dosing specifically for human hepatocytes. Results: During early steatosis, intracellular lipid droplets displaced microtubules altering mitochondrial distribution, and disrupted the F-actin network, leading to loss of bile canaliculi in steatotic hepatocytes. Basal mitochondrial respiration, maximum respiratory capacity, and resistance to H2O2-induced cell death also increased as an adaptative response. Upon reversal of steatosis, F-actin and bile canaliculi were restored in hepatocytes. Nevertheless, we observed an increase in elongated mitochondrial branches accompanied by decreases in α-tubulin expression, mitochondrial proton leak, and susceptibility to H2O2-induced cell death. Conclusions: Despite the restoration of cytoskeletons morphologically upon reversal of steatosis, the mitochondria in hepatocytes were impaired owing to early adaptative respiratory increase. Hepatocytes thus were highly predisposed to H2O2-induced cell death. These results indicate the persistence of potential health risks for recovering NAFLD patients.http://www.sciencedirect.com/science/article/pii/S2352345X23000541Nonalcoholic Fatty Liver DiseaseSteatosisCytoskeletonMitochondria |
| spellingShingle | Letao Fan Aslihan Gokaltun Sarah Maggipinto Yoshinori Kitagawa Jeevendra Martyn Heidi Yeh Basak E. Uygun Martin L. Yarmush O. Berk Usta Alterations in Cytoskeleton and Mitochondria in the Development and Reversal of Steatosis in Human HepatocytesSummary Cellular and Molecular Gastroenterology and Hepatology Nonalcoholic Fatty Liver Disease Steatosis Cytoskeleton Mitochondria |
| title | Alterations in Cytoskeleton and Mitochondria in the Development and Reversal of Steatosis in Human HepatocytesSummary |
| title_full | Alterations in Cytoskeleton and Mitochondria in the Development and Reversal of Steatosis in Human HepatocytesSummary |
| title_fullStr | Alterations in Cytoskeleton and Mitochondria in the Development and Reversal of Steatosis in Human HepatocytesSummary |
| title_full_unstemmed | Alterations in Cytoskeleton and Mitochondria in the Development and Reversal of Steatosis in Human HepatocytesSummary |
| title_short | Alterations in Cytoskeleton and Mitochondria in the Development and Reversal of Steatosis in Human HepatocytesSummary |
| title_sort | alterations in cytoskeleton and mitochondria in the development and reversal of steatosis in human hepatocytessummary |
| topic | Nonalcoholic Fatty Liver Disease Steatosis Cytoskeleton Mitochondria |
| url | http://www.sciencedirect.com/science/article/pii/S2352345X23000541 |
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