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Effects of Pro-Inflammatory Cytokines on Hepatic Metabolism in Primary Human Hepatocytes. Int J Mol Sci 2022; 23:ijms232314880. [PMID: 36499207 PMCID: PMC9740548 DOI: 10.3390/ijms232314880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/23/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Three decades of hepatocyte transplantation have confirmed such a cell-based approach as an adjunct or alternative treatment to solid organ transplantation. Donor cell survival and engraftment were indirectly measured by hepatospecific secretive or released metabolites, such as ammonia metabolism in urea cycle defects. In cases of sepsis or viral infection, ammonia levels can significantly and abruptly increase in these recipients, erroneously implying rejection. Pro-inflammatory cytokines associated with viral or bacterial infections are known to affect many liver functions, including drug-metabolizing enzymes and hepatic transport activities. We examined the influence of pro-inflammatory cytokines in primary human hepatocytes, isolated from both normal donors or patients with metabolic liver diseases. Different measures of hepatocyte functions, including ammonia metabolism and phase 1-3 metabolism, were performed. All the hepatic functions were profoundly and significantly suppressed after exposure to concentrations of from 0.1 to 10 ng/mL of different inflammatory cytokines, alone and in combination. Our data indicate that, like phase I metabolism, suppression of phase II/III and ammonia metabolism occurs in hepatocytes exposed to pro-inflammatory cytokines in the absence of cell death. Such inflammatory events do not necessarily indicate a rejection response or loss of the cell graft, and these systemic inflammatory signals should be carefully considered when the immunosuppressant regiment is reduced or relieved in a hepatocyte transplantation recipient in response to such alleged rejection.
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Tarasenko TN, Jestin M, Matsumoto S, Saito K, Hwang S, Gavrilova O, Trivedi N, Zerfas PM, Barca E, DiMauro S, Senac J, Venditti CP, Cherukuri M, McGuire PJ. Macrophage derived TNFα promotes hepatic reprogramming to Warburg-like metabolism. J Mol Med (Berl) 2019; 97:1231-1243. [PMID: 31053970 DOI: 10.1007/s00109-019-01786-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 03/26/2019] [Accepted: 04/02/2019] [Indexed: 02/07/2023]
Abstract
During infection, hepatocytes must undergo a reprioritization of metabolism, termed metabolic reprogramming. Hepatic metabolic reprogramming in response to infection begins within hours of infection, suggesting a mechanism closely linked to pathogen recognition. Following injection with polyinosinic:polycytidylic acid, a mimic of viral infection, a robust hepatic innate immune response could be seen involving the TNFα pathway at 2 h. Repeated doses led to the adoption of Warburg-like metabolism in the liver as determined by in vivo metabolic imaging, expression analyses, and metabolomics. Hepatic macrophages, Kupffer cells, were able to induce Warburg-like metabolism in hepatocytes in vitro via TNFα. Eliminating macrophages in vivo or blocking TNFα in vitro or in vivo resulted in abrogation of the metabolic phenotype, establishing an immune-metabolic axis in hepatic metabolic reprogramming. Overall, we suggest that macrophages, as early sensors of pathogens, instruct hepatocytes via TNFα to undergo metabolic reprogramming to cope with challenges to homeostasis initiated by infection. This work not only addresses a key component of end-organ physiology, but also raises questions about the side effects of biologics in the treatment of inflammatory diseases. KEY MESSAGES: • Hepatocytes develop Warburg-like metabolism in vivo during viral infection. • Macrophage TNFα promotes expression of glycolytic enzymes in hepatocytes. • Blocking this immune-metabolic axis abrogates Warburg-like metabolism in the liver. • Implications for patients being treated for inflammatory diseases with biologics.
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Affiliation(s)
- Tatyana N Tarasenko
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 49 Convent Drive, Room 4A62, Bethesda, MD, 20892, USA
| | - Maxim Jestin
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 49 Convent Drive, Room 4A62, Bethesda, MD, 20892, USA
| | - Shingo Matsumoto
- Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Keita Saito
- National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sean Hwang
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 49 Convent Drive, Room 4A62, Bethesda, MD, 20892, USA
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Niraj Trivedi
- Social Behavioral Research Branch, National Institutes of Health, Bethesda, MD, USA
| | - Patricia M Zerfas
- Office of Research Services, Division of Veterinary Resources, National Institutes of Health, Bethesda, MD, USA
| | - Emanuele Barca
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Salvatore DiMauro
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Julien Senac
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 49 Convent Drive, Room 4A62, Bethesda, MD, 20892, USA
| | - Charles P Venditti
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 49 Convent Drive, Room 4A62, Bethesda, MD, 20892, USA
| | - Murali Cherukuri
- National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Peter J McGuire
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 49 Convent Drive, Room 4A62, Bethesda, MD, 20892, USA.
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Luan Q, Cahoon S, Wu A, Bale SS, Yarmush M, Bhushan A. A microfluidic in-line ELISA for measuring secreted protein under perfusion. Biomed Microdevices 2017; 19:101. [PMID: 29128921 PMCID: PMC6335147 DOI: 10.1007/s10544-017-0244-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Recent progress in the development of microfluidic microphysiological systems such as 'organs-on-chips' and microfabricated cell culture is geared to simulate organ-level physiology. These tissue models leverage microengineering technologies that provide capabilities of presenting cultured cells with input signals in a more physiologically relevant context such as perfused flow. Proteins that are secreted from cells have important information about the health of the cells. Techniques to quantify cellular proteins include mass spectrometry to ELISA (enzyme-linked immunosorbent assay). Although our capability to perturb the cells in the microphysiological systems with varying inputs is well established, we lack the tools to monitor in-line the cellular responses. User intervention for sample collection and off-site is cumbersome, causes delays in obtaining results, and is especially expensive because of collection, storage, and offline processing of the samples, and in many case, technically impractical to carry out because of limitated sample volumes. To address these shortcomings, we report the development of an ELISA that is carried out in-line under perfusion within a microfluidic device. Using this assay, we measured the albumin secreted from perfused hepatocytes without and under stimulation by IL-6. Since the method is based on a sandwich ELISA, we envision broad application of this technology to not just organs-on-chips but also to characterizing the temporal release and measurement of soluble factors and response to drugs.
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Affiliation(s)
- Qiyue Luan
- Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Stacey Cahoon
- Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Agnes Wu
- Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Shyam Sundhar Bale
- Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Martin Yarmush
- Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ, 08854, USA
| | - Abhinav Bhushan
- Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA.
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Tarasenko TN, McGuire PJ. The liver is a metabolic and immunologic organ: A reconsideration of metabolic decompensation due to infection in inborn errors of metabolism (IEM). Mol Genet Metab 2017; 121:283-288. [PMID: 28666653 PMCID: PMC5553615 DOI: 10.1016/j.ymgme.2017.06.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/22/2017] [Accepted: 06/23/2017] [Indexed: 12/30/2022]
Abstract
Metabolic decompensation in inborn errors of metabolism (IEM) is characterized by a rapid deterioration in metabolic status leading to life-threatening biochemical perturbations (e.g. hypoglycemia, hyperammonemia, acidosis, organ failure). Infection is the major cause of metabolic decompensation in patients with IEM. We hypothesized that activation of the immune system during infection leads to further perturbations in end-organ metabolism resulting in increased morbidity. To address this, we established model systems of metabolic decompensation due to infection. Using these systems, we have described the pathologic mechanisms of metabolic decompensation as well as changes in hepatic metabolic reserve associated with infection. First and foremost, our studies have demonstrated that the liver experiences a significant local innate immune response during influenza infection that modulates hepatic metabolism. Based on these findings, we are the first to suggest that the role of the liver as a metabolic and immunologic organ is central in the pathophysiology of metabolic decompensation due to infection in IEM. The dual function of the liver as a major metabolic regulator and a lymphoid organ responsible for immunosurveillance places this organ at risk for hepatotoxicity. Mobilization of hepatic reserve and the regenerative capacity of a healthy liver compensates for this calculated risk. However, activation of the hepatic innate immune system may be deleterious in IEM. Based on this assertion, strategies aimed at modulating the innate immune response may be a viable target for intervention in the treatment of hepatic metabolic decompensation.
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Affiliation(s)
- Tatyana N Tarasenko
- Metabolism, Infection and Immunity Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Peter J McGuire
- Metabolism, Infection and Immunity Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States.
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Vu LT, Orbach SM, Ray WK, Cassin ME, Rajagopalan P, Helm RF. The hepatocyte proteome in organotypic rat liver models and the influence of the local microenvironment. Proteome Sci 2017; 15:12. [PMID: 28649179 PMCID: PMC5480101 DOI: 10.1186/s12953-017-0120-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 06/15/2017] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Liver models that closely mimic the in vivo microenvironment are useful for understanding liver functions, capabilities, and intercellular communication processes. Three-dimensional (3D) liver models assembled using hepatocytes and liver sinusoidal endothelial cells (LSECs) separated by a polyelectrolyte multilayer (PEM) provide a functional system while also permitting isolation of individual cell types for proteomic analyses. METHODS To better understand the mechanisms and processes that underlie liver model function, hepatocytes were maintained as monolayers and 3D PEM-based formats in the presence or absence of primary LSECs. The resulting hepatocyte proteomes, the proteins in the PEM, and extracellular levels of urea, albumin and glucose after three days of culture were compared. RESULTS All systems were ketogenic and found to release glucose. The presence of the PEM led to increases in proteins associated with both mitochondrial and peroxisomal-based β-oxidation. The PEMs also limited production of structural and migratory proteins associated with dedifferentiation. The presence of LSECs increased levels of Phase I and Phase II biotransformation enzymes as well as several proteins associated with the endoplasmic reticulum and extracellular matrix remodeling. The proteomic analysis of the PEMs indicated that there was no significant change after three days of culture. These results are discussed in relation to liver model function. CONCLUSIONS Heterotypic cell-cell and cell-ECM interactions exert different effects on hepatocyte functions and phenotypes.
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Affiliation(s)
- Lucas T. Vu
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061 USA
| | - Sophia M. Orbach
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061 USA
| | - W. Keith Ray
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061 USA
| | - Margaret E. Cassin
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061 USA
| | - Padmavathy Rajagopalan
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061 USA
- School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, Virginia 24061 USA
- ICTAS Center for Systems Biology and Engineered Tissues, Virginia Tech, Blacksburg, Virginia 24061 USA
| | - Richard F. Helm
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061 USA
- ICTAS Center for Systems Biology and Engineered Tissues, Virginia Tech, Blacksburg, Virginia 24061 USA
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Hackett ES, Mama KR, Twedt DC, Gustafson DL. Evaluation of antioxidant capacity and inflammatory cytokine gene expression in horses fed silibinin complexed with phospholipid. Am J Vet Res 2013; 74:1333-9. [PMID: 24066918 DOI: 10.2460/ajvr.74.10.1333] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate antioxidant capacity and inflammatory cytokine gene expression in horses fed silibinin complexed with phospholipid. ANIMALS 5 healthy horses. PROCEDURES Horses consumed increasing orally administered doses of silibinin phospholipid during 4 nonconsecutive weeks (0 mg/kg, 6.5 mg/kg, 13 mg/kg, and 26 mg/kg of body weight, twice daily for 7 days each week). Dose-related changes in plasma antioxidant capacity, peripheral blood cell glutathione concentration and antioxidant enzyme activities, and blood cytokine gene expression were evaluated. RESULTS Plasma antioxidant capacity increased throughout the study period with increasing dose. Red blood cell nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase I activity decreased significantly with increasing doses of silibinin phospholipid. No significant differences were identified in glutathione peroxidase activity, reduced glutathione or oxidized glutathione concentrations, or expression of tumor necrosis factor α, interleukin-1, or interleukin-2. CONCLUSIONS AND CLINICAL RELEVANCE Minor alterations in antioxidant capacity of healthy horses that consumed silibinin phospholipid occurred and suggest that further study in horses with liver disease is indicated.
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Affiliation(s)
- Eileen S Hackett
- Department of Clinical Sciences, College of Veterinary Medicine and Biological Sciences, Colorado State University, Fort Collins, CO. 80523
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Au AY, Hasenwinkel JM, Frondoza CG. Micropatterned agarose scaffolds covalently modified with collagen for culture of normal and neoplastic hepatocytes. J Biomed Mater Res A 2011; 100:342-52. [DOI: 10.1002/jbm.a.33277] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 09/12/2011] [Indexed: 11/08/2022]
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de David C, Rodrigues G, Bona S, Meurer L, González-Gallego J, Tuñón MJ, Marroni NP. Role of quercetin in preventing thioacetamide-induced liver injury in rats. Toxicol Pathol 2011; 39:949-57. [PMID: 21885874 DOI: 10.1177/0192623311418680] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In hepatic toxicity induced in rats by two injections of thioacetamide (TAA, 350 mg/kg with an interval of 8 hr), the action of quercetin was investigated. After 96 hr, TAA administration resulted in hepatic necrosis, significant increases in serum transaminase activity, and increases in hepatic lipoperoxidation. Thioacetamide-induced hepatotoxicity also showed changes in antioxidant enzymes in the liver of rats, with alterations in p-ERK 1/2 (phosphorylated extracellular-signal related kinase 1/2) as well as an imbalance between proapototic protein Bax and anti-apoptotic protein Bcl-2 expression. With administration of the flavonoid quercetin (50 mg/Kg i.p.) for four consecutive days following TAA, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity were close to normal values in rats. Histological findings suggested that quercetin had a preventive effect on TAA-induced hepatic necrosis. Quercetin treatment caused significant decreases in lipid peroxide levels in the TAA-treated rats, with some changes in antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Quercetin also inhibited the change of the p-ERK1/2 by TAA and significantly prevented the increase in Bax/Bcl-2 ratio, thus preventing apoptosis. Findings indicate that quercetin may have a preventive effect on TAA-induced hepatotoxicity by modulating the oxidative stress parameters and apoptosis pathway.
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Affiliation(s)
- Cíntia de David
- Laboratory of Experimental Hepatology and Physiology, Porto Alegre Clinical Hospital, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
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Au AY, Hasenwinkel JM, Frondoza CG. Silybin inhibits interleukin-1β-induced production of pro-inflammatory mediators in canine hepatocyte cultures. J Vet Pharmacol Ther 2011; 34:120-9. [PMID: 21395602 DOI: 10.1111/j.1365-2885.2010.01200.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hepatocytes are highly susceptible to cytokine stimulation and are fundamental to liver function. We established primary canine hepatocyte cultures to study effects of anti-inflammatory agents with hepatoprotective properties. Hepatocyte cultures were incubated with control media alone, silybin (SB), or the more bioavailable silybin-phosphatidylcholine complex (SPC), followed by activation with interleukin-1 beta (IL-1β; 10 ng/mL). Inflammatory response was measured by prostaglandin E2 (PGE(2) ), interleukin-8 (IL-8), and monocyte chemotactic protein-1 (MCP-1) production and also nuclear factor-kappa B (NF-κB) translocation. Hepatocyte cultures continued production of the phenotypic marker albumin for more than 7 days in culture. IL-1β exposure increased PGE(2) , IL-8, and MCP-1 production, which was paralleled by NF-κB translocation from the cytoplasm to the nucleus. Pretreatment with SB and SPC significantly inhibited IL-1β-induced production of pro-inflammatory markers and attenuated NF-κB nuclear translocation. We demonstrate for the first time that primary canine hepatocyte cultures can be maintained in culture without phenotypic loss. The observation that hepatocyte cultures respond to pro-inflammatory IL-1β activation indicates hepatocytes as primary cellular targets of extrinsic IL-1β. The ability of SB and SPC to inhibit hepatocyte culture activation by IL-1β reinforces the notion of their hepatoprotective effects. Our primary canine hepatocyte culture model facilitates identification of hepatoprotective agents and their mechanism of action.
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Affiliation(s)
- A Y Au
- Research and Development, Nutramax Laboratories, Inc., Edgewood, MD 21040, USA
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Sharma NS, Wallenstein EJ, Novik E, Maguire T, Schloss R, Yarmush ML. Enrichment of hepatocyte-like cells with upregulated metabolic and differentiated function derived from embryonic stem cells using S-NitrosoAcetylPenicillamine. Tissue Eng Part C Methods 2009; 15:297-306. [PMID: 19196121 DOI: 10.1089/ten.tec.2008.0303] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The generation of a large number of fully functional hepatocytes from a renewable cell source can provide an unlimited resource for bioartificial liver devices and cell replacement therapies. We have established a directed differentiation system using sodium butyrate treatment to generate an enriched population of hepatocyte-like cells from embryonic stem cells. A metabolic analysis of the hepatocyte populations revealed glycolytic and mitochondrial phenotypes similar to mouse hepatoma cells, implying that these cells represent an immature hepatocyte phenotype. To mediate further differentiation, S-NitrosoAcetylPenicillamine (SNAP), a nitric oxide donor, was utilized to induce mitochondrial development in the precursor populations. A comparative analysis of the different treated populations showed that 500microM SNAP treatment resulted in the generation of an enriched population of metabolically mature hepatocyte-like cells with increased differentiated function. Specifically, 500microM SNAP treatment increased glucose consumption, lactate production rates, mitochondrial mass, and potential as compared to untreated populations. In addition, functional analysis revealed that intracellular albumin content, urea secretion rates, and cytochrome P450 7a1 promoter activity were increased in the treated population. The methodology described here to generate an enriched population of metabolically and functionally mature hepatocyte-like cells may have potential implications in drug discovery and regenerative medicine.
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Affiliation(s)
- Nripen S Sharma
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey, USA
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Wen YA, Liu D, Xiao YY, Luo D, Dong YF, Zhang LP. Enhanced glucose synthesis in three-dimensional hepatocyte collagen matrix. Toxicol In Vitro 2009; 23:744-7. [PMID: 19268699 DOI: 10.1016/j.tiv.2009.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2008] [Revised: 12/31/2008] [Accepted: 02/22/2009] [Indexed: 10/21/2022]
Abstract
Three-dimensional (3D) cell culture model offers a unique opportunity to study hepatocytes that require extracellular matrix to keep the cells at the differentiated state. In this report, we cultured isolated mouse hepatocytes in a 3D collagen matrix system and developed a protocol to measure glucose production at 3h, 6h, 18h and 24h after culture. The results demonstrated that hepatocytes cultured under 3D collagen matrix condition consistently produced glucose at 240-290 mg/10(6) cells for up to 24h. Contrarily, hepatocytes cultured under traditional monolayer condition produced less than 50 mg/10(6) cells glucose. We demonstrated higher expression of phosphoenolpyruvate carboxykinase (PEPCK), a key enzyme for the synthesis of glucose from pyruvate, and CCAAT/enhancer-binding protein alpha (C/EBPalpha), an important liver-specific transcription factor, under the 3D collagen matrix culture condition in comparison to the monolayer condition. Thus, the 3D collagen matrix system preserved metabolic function of hepatocytes and can be used as an in vitro model for studying hepatocyte glucose production and gluconeogenesis.
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Affiliation(s)
- Yang-an Wen
- Dept. of Clinical Laboratory Medicine, The First Affiliated Hospital, Chongqing Medical University, Yuzhong District, Chongqing 400016, PR China
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Broughan TA, Naukam R, Tan C, Van De Wiele CJ, Refai H, Teague TK. Effects of hepatic zonal oxygen levels on hepatocyte stress responses. J Surg Res 2007; 145:150-60. [PMID: 18164035 DOI: 10.1016/j.jss.2007.04.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 04/05/2007] [Accepted: 04/09/2007] [Indexed: 12/17/2022]
Abstract
BACKGROUND Hepatocytes spend their lifetimes in a gradient of oxygen, hormones, and enzymes. We used a three-dimensional Matrigel model to determine whether hepatocytes cultured at perivenous (zone 3) oxygen levels differed in susceptibility to anoxia-induced cell injury compared with hepatocytes cultured at periportal (zone 1) oxygen levels. MATERIALS AND METHODS Hepatocytes were harvested from Sprague Dawley rats and cultured at 9% oxygen (hepatic zone 1) or 5% oxygen (hepatic zone 3) and stressed at 0% oxygen. Microscopy, real-time reverse transcriptase-polymerase chain reaction, and enzyme-linked immunosorbent assay were used to assess cell viability, mitochondrial potential, acute phase responses, and membrane blebbing. RESULTS Hepatocytes cultured in Matrigel with HepatoZyme medium at zone 1 and zone 3 oxygen conditions were viable for 1 wk and showed acute phase responses as measured by interleukin-6-induced fibrinogen production. In response to 3 h anoxia, cells maintained at the perivenous oxygen level showed increased membrane blebbing and increased loss of mitochondrial membrane potential in comparison to the periportal oxygen cultured cells. Cells at perivenous oxygen also showed a reduced ability to recover following reoxygenation. CONCLUSIONS Hepatocytes can remain viable and functional for extended periods in culture at low oxygen levels that mimic the hepatic perivenous environment, yet these cells are more susceptible to anoxia-induced damage than hepatocytes cultured at the periportal oxygen level. The small population of perivenous hepatocytes may be critical in determining the fate of the liver during ischemia/reperfusion since hepatocytes cultured at that concentration appear to be more labile in response to anoxia.
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Affiliation(s)
- Thomas A Broughan
- Department of Surgery, University of Oklahoma College of Medicine, Tulsa, Oklahoma 74135, USA
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King KR, Wang S, Irimia D, Jayaraman A, Toner M, Yarmush ML. A high-throughput microfluidic real-time gene expression living cell array. LAB ON A CHIP 2007; 7:77-85. [PMID: 17180208 PMCID: PMC3205973 DOI: 10.1039/b612516f] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The dynamics of gene expression are fundamental to the coordination of cellular responses. Measurement of temporal gene expression patterns is currently limited to destructive low-throughput techniques such as northern blotting, reverse transcription polymerase chain reaction (RT-PCR), and DNA microarrays. We report a scalable experimental platform that combines microfluidic addressability with quantitative live cell imaging of fluorescent protein transcriptional reporters to achieve real-time characterization of gene expression programs in living cells. Integrated microvalve arrays control row-seeding and column-stimulation of 256 nanoliter-scale bioreactors to create a high density matrix of stimulus-response experiments. We demonstrate the approach in the context of hepatic inflammation by acquiring approximately 5000 single-time-point measurements in each automated and unattended experiment. Experiments can be assembled in hours and perform the equivalent of months of conventional experiments. By enabling efficient investigation of dynamic gene expression programs, this technology has the potential to make significant impacts in basic science, drug development, and clinical medicine.
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Affiliation(s)
- Kevin R. King
- Center for Engineering and Medicine and Department of Surgery, Massachusetts General Hospital, 51 Blosson St. Rm 406, Boston, MA 02114, USA; Fax: (617) 371-4950; Tel: (617) 371-4882
- Massachusetts Institute of Technology, Division of Health Science and Technology, Boston, MA 02114, USA
- Shriners Hospitals for Children, and Harvard Medical School, Boston, MA 02114, USA
| | - Sihong Wang
- Center for Engineering and Medicine and Department of Surgery, Massachusetts General Hospital, 51 Blosson St. Rm 406, Boston, MA 02114, USA; Fax: (617) 371-4950; Tel: (617) 371-4882
- Shriners Hospitals for Children, and Harvard Medical School, Boston, MA 02114, USA
| | - Daniel Irimia
- Center for Engineering and Medicine and Department of Surgery, Massachusetts General Hospital, 51 Blosson St. Rm 406, Boston, MA 02114, USA; Fax: (617) 371-4950; Tel: (617) 371-4882
- Shriners Hospitals for Children, and Harvard Medical School, Boston, MA 02114, USA
| | - Arul Jayaraman
- Department of Chemical Engineering, Texas A&M University, Boston, MA 02114, USA
| | - Mehmet Toner
- Center for Engineering and Medicine and Department of Surgery, Massachusetts General Hospital, 51 Blosson St. Rm 406, Boston, MA 02114, USA; Fax: (617) 371-4950; Tel: (617) 371-4882
- Massachusetts Institute of Technology, Division of Health Science and Technology, Boston, MA 02114, USA
- Shriners Hospitals for Children, and Harvard Medical School, Boston, MA 02114, USA
| | - Martin L. Yarmush
- Center for Engineering and Medicine and Department of Surgery, Massachusetts General Hospital, 51 Blosson St. Rm 406, Boston, MA 02114, USA; Fax: (617) 371-4950; Tel: (617) 371-4882
- Massachusetts Institute of Technology, Division of Health Science and Technology, Boston, MA 02114, USA
- Shriners Hospitals for Children, and Harvard Medical School, Boston, MA 02114, USA
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Jayaraman A, Roberts KA, Yoon J, Yarmush DM, Duan X, Lee K, Yarmush ML. Identification of neutrophil gelatinase-associated lipocalin (NGAL) as a discriminatory marker of the hepatocyte-secreted protein response to IL-1beta: a proteomic analysis. Biotechnol Bioeng 2005; 91:502-15. [PMID: 15918168 DOI: 10.1002/bit.20535] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The liver is the major source of proteins used throughout the body for various functions. Upon injury or infection, an acute phase response (APR) is initiated in the liver that is primarily mediated by inflammatory cytokines such as interleukin-1beta (IL-1beta) and interleukin-6. Among others, the APR is characterized by an altered protein synthetic profile. We used two-dimensional gel electrophoresis to study the dynamics of changes in protein synthesis in hepatocytes exposed to these inflammatory cytokines. Protein profiles were quantified using image analysis and further analyzed using multivariate statistical methods. Our results indicate that IL-1beta and IL-6 each induces secreted protein responses with distinct dynamics and dose-dependence. Parallel stimulation by IL-1beta and IL-6 results in a protein pattern indistinguishable from the IL-1beta pattern, indicating a dominant effect of IL-1beta over IL-6 at the doses tested. Multidimensional scaling (MDS) of correlation distances between protein secretion levels revealed two protein pairs that are robustly co-secreted across the various cytokine stimulation conditions, suggesting shared regulatory pathways. Finally, we also used multivariate alternating conditional expectation (MACE) to identify transformation functions that discriminated the cytokine-stimulated and untreated hepatocyte-secreted protein profiles. Our analysis indicates that the expression of neutrophil gelatinase-associated lipocalin (NGAL) was sufficient to discriminate between IL-1beta and IL-6 stimulation. The combination of proteomics and multivariate analysis is expected to provide new information on the cellular regulatory networks involved in generating specific cellular responses.
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Affiliation(s)
- Arul Jayaraman
- Center for Engineering in Medicine/Department of Surgery Massachusetts General Hospital, Shriners Burns Hospital, Boston; and Harvard Medical School, Boston, Massachusetts 02114, USA.
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15
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Jayaraman A, Yarmush ML, Roth CM. Evaluation of an in vitro model of hepatic inflammatory response by gene expression profiling. ACTA ACUST UNITED AC 2005; 11:50-63. [PMID: 15738661 DOI: 10.1089/ten.2005.11.50] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The body's response to biochemical stress involves coordinated changes in the expression of several sets of genes that regulate its return to homeostasis. Although several cell culture systems have been utilized for studying such complex physiological events in vitro, their assessment has been limited to biochemical assays on individual genes and proteins, limiting interpretation of the results in a systems context. Advances in genomics provide an opportunity to provide a more comprehensive assessment. In this study, we have used DNA microarrays to profile gene expression dynamics during interleukin 6-stimulated inflammation in hepatocytes maintained in a stable, collagen double-gel in vitro model system. The observed expression profile was also compared with that obtained from rat liver tissue after burn injury to determine the extent and nature of responses captured by the in vitro system. Our results indicate that several aspects of the in vivo hepatic inflammatory response can be captured by the in vitro system at the molecular systems level. Statistical analysis of the mRNA profiles was also used to characterize the temporal response in each model system and demonstrate similar behavior. A small panel of molecules involved in the hepatic acute-phase response was also profiled, using quantitative kinetic polymerase chain reaction, to confirm these observations. These results indicate the utility of the stable hepatocyte culture system for expression profiling of inflammatory states and for providing insights into the interplay of changes in gene expression during complex physiological states.
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Affiliation(s)
- Arul Jayaraman
- Shriners Burns Hospital, Harvard Medical School, Boston, Massachusetts, USA
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16
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Martínez-Flórez S, Gutiérrez-Fernández B, Sánchez-Campos S, González-Gallego J, Tuñón MJ. Quercetin attenuates nuclear factor-kappaB activation and nitric oxide production in interleukin-1beta-activated rat hepatocytes. J Nutr 2005; 135:1359-65. [PMID: 15930438 DOI: 10.1093/jn/135.6.1359] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We investigated whether different concentrations of the flavonoid quercetin ameliorate nitric oxide production and nuclear factor (NF)-kappaB activation in interleukin (IL)-1beta-activated rat hepatocytes. Primary cultures of rat hepatocytes were treated with IL-1beta alone or with quercetin in concentrations ranging from 5 to 100 micromol/L. The generation of reactive oxygen species, assessed by flow cytometry using dichlorodihydrofluorescein diacetate, was significantly reduced, and the oxidized:reduced glutathione ratio decreased in cultures treated with 50 and 100 micromol/L of quercetin. Quercetin at 100 micromol/L significantly prevented the IL-1beta-induced release of nitrite into the culture medium. Western blot and reverse transcription-PCR analyses demonstrated that increased levels of inducible nitric oxide synthase (iNOS) protein and mRNA in hepatocytes stimulated by IL-1beta were prevented by 50 micromol/L and 100 micromol/L of quercetin. Electrophoretic mobility shift assay experiments and Western blots indicated that quercetin blocked the activation of NF-kappaB and decreased the inhibitor kappaB protein levels induced by IL-1beta. In summary, quercetin, a natural flavonol widely distributed in the human diet, inhibits NO production in IL-1beta-stimulated hepatocytes through the inhibition of iNOS expression. Although the mode of action remains to be clarified, our findings support the view that the mechanism of action is via inhibition of IL-1beta-induced NF-kappaB activation.
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17
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Morand JPF, Macri J, Adeli K. Proteomic Profiling of Hepatic Endoplasmic Reticulum-associated Proteins in an Animal Model of Insulin Resistance and Metabolic Dyslipidemia. J Biol Chem 2005; 280:17626-33. [PMID: 15760893 DOI: 10.1074/jbc.m413343200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hepatic insulin resistance and lipoprotein overproduction are common features of the metabolic syndrome and insulin-resistant states. A fructose-fed, insulin-resistant hamster model was recently developed to investigate mechanisms linking the development of hepatic insulin resistance and overproduction of atherogenic lipoproteins. Here we report a systematic analysis of protein expression profiles in the endoplasmic reticulum (ER) fractions isolated from livers of fructose-fed hamsters with the intention of identifying new candidate proteins involved in hepatic complications of insulin resistance and lipoprotein dysregulation. We have profiled hepatic ER-associated proteins from chow-fed (control) and fructose-fed (insulin-resistant) hamsters using two-dimensional gel electrophoresis and mass spectrometry. A total of 26 large scale two-dimensional gels of hepatic ER were used to identify 34 differentially expressed hepatic ER protein spots observed to be at least 2-fold differentially expressed with fructose feeding and the onset of insulin resistance. Differentially expressed proteins were identified by matrix-assisted laser desorption ionization-quadrupole time of flight (MALDI-Q-TOF), MALDI-TOF-postsource decay, and database mining using ProteinProspector MS-fit and MS-tag or the PROWL ProFound search engine using a focused rodent or mammalian search. Hepatic ER proteins ER60, ERp46, ERp29, glutamate dehydrogenase, and TAP1 were shown to be more than 2-fold down-regulated, whereas alpha-glucosidase, P-glycoprotein, fibrinogen, protein disulfide isomerase, GRP94, and apolipoprotein E were all found to be up-regulated in the hepatic ER of the fructose-fed hamster. Seven isoforms of ER60 in the hepatic ER were all shown to be down-regulated at least 2-fold in hepatocytes from fructosefed/insulin-resistant hamsters. Implications of the differential expression of positively identified protein factors in the development of hepatic insulin resistance and lipoprotein abnormalities are discussed.
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Affiliation(s)
- Jean-Paul F Morand
- Division of Clinical Biochemistry, and Structural Biology and Biochemistry, Department of Pediatric Laboratory Medicine, Research Institute, The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
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18
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Auth MKH, Woitaschek D, Beste M, Schreiter T, Kim HS, Oppermann E, Joplin RE, Baumann U, Hilgard P, Nadalin S, Markus BH, Blaheta RA. Preservation of the synthetic and metabolic capacity of isolated human hepatocytes by coculture with human biliary epithelial cells. Liver Transpl 2005; 11:410-9. [PMID: 15776438 DOI: 10.1002/lt.20367] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bioartificial liver support systems have demonstrated limited efficacy in compensation of liver detoxification and substitution of liver-derived factors. However, in these devices, the biological substitution of the complex liver function has been restricted to xenogeneic or transformed hepatocytes. Therefore, we have examined the long-term effect of coculturing normal human hepatocytes (HCs) with allogeneic biliary epithelial cells (BECs). We applied functional in vitro assays to examine their metabolic potential by ammonia detoxification to urea, cytochrome P450-dependent lignocaine conversion to mono-ethyl-glycine-xylidide (MEGX), and protein expression and secretion. As the liver has a pivotal role in the synthesis of coagulation factors, we measured antithrombin III (AT III), factor VII, and albumin, comparing HCs plated on collagen or inside 3-dimensional collagen gels. Over 30 days, expression and secretion of albumin and clotting factors by human HCs were augmented by culture inside collagen gel, but were also enhanced and better maintained by coculture with BECs. Higher proportions of BECs cocultured with HCs substantially increased the protein synthesis and urea production. Remarkably, the almost absent cytochrome P450 activity of HC alone after 1 week could be reversed and maintained over 3 weeks by coculture with BECs. The pattern of these effects differed from the extent of interleukin-6 (IL-6) production and HC viability under the compared conditions. In conclusion, coculture of human HCs with BECs impressively restores the synthetic and metabolic liver function in vitro. These results suggest mechanisms of improved liver epithelial differentiation supported by coculture conditions. This technique offers new perspectives in bioartificial liver support, hepatocyte transplantation, and stem cell differentiation.
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Affiliation(s)
- Marcus K H Auth
- Children's Hospital, Department of General Pediatrics, Essen, Germany.
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Farkas D, Tannenbaum SR. Characterization of chemically induced hepatotoxicity in collagen sandwiches of rat hepatocytes. Toxicol Sci 2005; 85:927-34. [PMID: 15772367 DOI: 10.1093/toxsci/kfi145] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
It has been shown that hepatocytes cultured in a collagen sandwich configuration maintain cell viability, morphology, and drug metabolizing activities for several weeks. The purpose of this study was to characterize chemically induced general toxicity in this system by exposing hepatocytes to eight different hepatotoxic compounds. Cell function and viability was measured by analyzing the secretions of urea and albumin and the release of lactate dehydrogenase. Significant decreases in urea and albumin secretions were detected after treatments with 32 nM aflatoxin B(1) and 1 mM doses of cadmium and the alkylating agents N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and methyl methane sulfonate (MMS). However, no significant toxicity could be measured following exposures to 5 mM carbon tetrachloride, 1 mM N, N-dimethylformamide (DMF), 1 mM vinyl acetate, and 1 mM acetaminophen. Western blots of cell lysates showed that hepatocytes maintained CYP1A, 2B, 3A2 but gradually lost CYP2E1, which is the main metabolic enzyme for acetaminophen, carbon tetrachloride, and DMF. The metabolites of acetaminophen were identified using liquid chromatography and electrospray mass spectrometry. It was determined that the hepatocytes converted most of the acetaminophen to the glucuronide and sulfate metabolites and only formed a small amount of the glutathione adduct. This research shows that the collagen sandwich culture system can only be used selectively for detecting hepatotoxicity and for identifying major metabolites of xenobiotic compounds.
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Affiliation(s)
- Dora Farkas
- Biological Engineering Division, Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
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Damelin LH, Coward S, Choudhury SF, Chalmers SA, Cox IJ, Robertson NJ, Revial G, Miles M, Tootle R, Hodgson HJF, Selden C. Altered mitochondrial function and cholesterol synthesis influences protein synthesis in extended HepG2 spheroid cultures. Arch Biochem Biophys 2004; 432:167-77. [PMID: 15542055 DOI: 10.1016/j.abb.2004.09.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Revised: 09/22/2004] [Indexed: 11/26/2022]
Abstract
Cultures of hepatocytes and HepG2 cells provide useful in vitro models of liver specific function. In this study, we investigated metabolic and biosynthetic function in 3-D HepG2 spheroid cultures, in particular to characterise changes on prolonged culture. We show that HepG2 cells cultured in spheroids demonstrate a reduction in mitochondrial membrane potential and respiration following 10 days of culture. This coincides with a modest reduction in glycolysis but an increase in glucose uptake where increased glycogen synthesis occurs at the expense of the intracellular ATP pool. Lowered biosynthesis coincides with and is linked to mitochondrial functional decline since low glucose-adapted spheroids, which exhibit extended mitochondrial function, have stable biosynthetic activity during extended culture although biosynthetic function is lower. This indicates that glucose is required for biosynthetic output but sustained mitochondrial function is required for the maintenance of biosynthetic function. Furthermore, we show that cholesterol synthesis is markedly increased in spheroids cf. monolayer culture and that inhibition of cholesterol synthesis by lovastatin extends mitochondrial and biosynthetic function. Therefore, increased cholesterol synthesis and/or its derivatives contributes to mitochondrial functional decline in extended HepG2 spheroid cultures.
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Affiliation(s)
- Leonard H Damelin
- Department of Medicine, Royal Free Campus, Royal Free and UCL Medical School, Rowland Hill Street, Hampstead, London, NW3 2PF, United Kingdom.
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Abstract
The inability of biomaterial scaffolds to functionally integrate into surrounding tissue is one of the major roadblocks to developing new biomaterials and tissue-engineering scaffolds. Despite considerable advances, current approaches to engineering cell-surface interactions fall short in mimicking the complexity of signals through which surrounding tissue regulates cell behavior. Cells adhere and interact with their extracellular environment via integrins, and their ability to activate associated downstream signaling pathways depends on the character of adhesion complexes formed between cells and their extracellular matrix. In particular, alpha5beta1 and alphavbeta3 integrins are central to regulating downstream events, including cell survival and cell-cycle progression. In contrast to previous findings that alphavbeta3 integrins promote angiogenesis, recent evidence argues that alphavbeta3 integrins may act as negative regulators of proangiogenic integrins such as alpha5beta1. This suggests that fibronectin is critical for scaffold vascularization because it is the only mammalian adhesion protein that binds and activates alpha5beta1 integrins. Cells are furthermore capable of stretching fibronectin matrices such that the protein partially unfolds, and recent computational simulations provide structural models of how mechanical stretching affects fibronectin function. We propose a model whereby excessive tension generated by cells in contact to biomaterials may in fact render fibronectin fibrils nonangiogenic and potentially inhibit vascularization. The model could explain why current biomaterials independent of their surface chemistries and textures fail to vascularize.
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Affiliation(s)
- Viola Vogel
- Department of Bioengineering and Center for Nanotechnology, University of Washington, Seattle, Washington 98195, USA.
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Berthiaume F, MacDonald AD, Kang YH, Yarmush ML. Control analysis of mitochondrial metabolism in intact hepatocytes: effect of interleukin-1beta and interleukin-6. Metab Eng 2003; 5:108-23. [PMID: 12850133 DOI: 10.1016/s1096-7176(03)00010-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) are produced by hepatic nonparenchymal cells after systemic injury and have been reported to inhibit ATP synthesis in hepatocytes, which may contribute to hepatic dysfunction in inflammatory states. To elucidate the mechanisms of action of IL-1beta and IL-6 on hepatocellular ATP synthesis, we measured the oxygen uptake rate (OUR) and mitochondrial membrane potential (MMP) of stable hepatocyte cultures, and analyzed the dynamic MMP response following the addition of mitochondrial inhibitors (antimycin A and oligomycin) with a model of mitochondrial metabolism. IL-1beta reduced mitochondrial OUR coupled to ATP synthesis via inhibition of phosphorylation reactions which dissipate the MMP, including ATP synthesis and consumption. Furthermore, the ATP synthesis rate in cytokine-free and IL-1beta-treated hepatocytes was controlled primarily by phosphorylation reactions, which corresponds to a state where the ATP synthesis rate closely follows the cellular energy demand. Thus, IL-1beta-mediated effects on electron transport and substrate oxidation reactions are not likely to significantly impact on ATP synthesis. IL-6 did not reduce mitochondrial OUR coupled to ATP synthesis, but shifted the control for ATP synthesis towards processes which generate the MMP, indicating that IL-6 induces a metabolic state where cellular functions are limited by the mitochondrial energy supply.
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Affiliation(s)
- François Berthiaume
- Center for Engineering in Medicine/Surgical Services, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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