1
|
Schelbert S, Schindeldecker M, Drebber U, Witzel HR, Weinmann A, Dries V, Schirmacher P, Roth W, Straub BK. Lipid Droplet-Associated Proteins Perilipin 1 and 2: Molecular Markers of Steatosis and Microvesicular Steatotic Foci in Chronic Hepatitis C. Int J Mol Sci 2022; 23:ijms232415456. [PMID: 36555099 PMCID: PMC9778710 DOI: 10.3390/ijms232415456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/29/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
Chronic infection with hepatitis C (HCV) is a major risk factor in the development of cirrhosis and hepatocellular carcinoma. Lipid metabolism plays a major role in the replication and deposition of HCV at lipid droplets (LDs). We have demonstrated the importance of LD-associated proteins of the perilipin family in steatotic liver diseases. Using a large collection of 231 human liver biopsies with HCV, perilipins 1 and 2 have been localized to LDs of hepatocytes that correlate with the degree of steatosis and specific HCV genotypes, but not significantly with the HCV viral load. Perilipin 1- and 2-positive microvesicular steatotic foci were observed in 36% of HCV liver biopsies, and also in chronic hepatitis B, autoimmune hepatitis and mildly steatotic or normal livers, but less or none were observed in normal livers of younger patients. Microvesicular steatotic foci did not frequently overlap with glycogenotic/clear cell foci as determined by PAS stain in serial sections. Steatotic foci were detected in all liver zones with slight architectural disarrays, as demonstrated by immunohistochemical glutamine synthetase staining of zone three, but without elevated Ki67-proliferation rates. In conclusion, microvesicular steatotic foci are frequently found in chronic viral hepatitis, but the clinical significance of these foci is so far not clear.
Collapse
Affiliation(s)
- Selina Schelbert
- Institute of Pathology, University Medical Center Mainz, 55131 Mainz, Germany
- Institute of Pathology, University Hospital Wuerzburg, 97080 Wuerzburg, Germany
| | | | - Uta Drebber
- Institute of Pathology, University Clinic Cologne, 50931 Cologne, Germany
| | - Hagen Roland Witzel
- Institute of Pathology, University Medical Center Mainz, 55131 Mainz, Germany
| | - Arndt Weinmann
- Department of Internal Medicine, University Medical Center, 55131 Mainz, Germany
| | - Volker Dries
- Institute of Pathology, University Clinic Cologne, 50931 Cologne, Germany
| | - Peter Schirmacher
- Institute of Pathology, University Medical Center Heidelberg, 69120 Heidelberg, Germany
| | - Wilfried Roth
- Institute of Pathology, University Medical Center Mainz, 55131 Mainz, Germany
| | - Beate Katharina Straub
- Institute of Pathology, University Medical Center Mainz, 55131 Mainz, Germany
- Correspondence: ; Tel.: +49-6131-17-7307
| |
Collapse
|
2
|
Tian S, Lei P, Teng C, Sun Y, Song X, Li B, Shan Y. Targeting PLIN2/PLIN5-PPARγ: Sulforaphane Disturbs the Maturation of Lipid Droplets. Mol Nutr Food Res 2019; 63:e1900183. [PMID: 31325205 DOI: 10.1002/mnfr.201900183] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 07/08/2019] [Indexed: 01/05/2023]
Abstract
SCOPE The effects of sulforaphane (SFN) on the maturation of lipid droplets (LDs)-the storage units for free fatty acids and sterols as triacylglycerides (TAG) and cholesterol esters (CE)-are far from being understood, despite the fact that SFN is known to be beneficial for ameliorating lipid metabolism disorders. METHODS AND RESULTS High-fat-intake models are established in both HHL-5 hepatocytes and rodents. The numbers and sizes of LDs are decreased by SFN. The accumulation of lipid core components (TAG & CE) is reduced and the expression of their key synthetases, acyl-coenzyme A: diacylglycerol acyltransferases 2 (DGAT2) and acyl-coenzyme A: cholesterol acyltransferases 1 (ACAT1), is also inhibited. Moreover, SFN decreases LD-associated protein PLIN2 and PLIN5 expression, but not that of PLIN1 and PLIN3, both in vivo and in vitro. Furthermore, over-expression of peroxisome proliferator-activated receptor gamma (PPARγ) induces the accumulation of TAG and the up-regulation of PLIN2 and PLIN5, which are not reversed by SFN. These results suggest that PPARγ may be a target of SFN in lipid metabolism. CONCLUSION SFN disturbs LD maturation by inhibiting the formation of the neutral lipid core and decreases PLIN2 and PLIN5 via down-regulation of PPARγ.
Collapse
Affiliation(s)
- Sicong Tian
- School of Public Health and Management, Wenzhou Medical University, Wenzhou, 325035, China
| | - Peng Lei
- Department of Food Science and Engineering, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Chunying Teng
- Department of Food Science and Engineering, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Yao Sun
- Department of Food Science and Engineering, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Xinyue Song
- Department of Food Science and Engineering, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Baolong Li
- Heilongjiang University of Chinese Medicine, Harbin, 150040, China
| | - Yujuan Shan
- School of Public Health and Management, Wenzhou Medical University, Wenzhou, 325035, China
| |
Collapse
|
3
|
Dejgaard SY, Presley JF. New Method for Quantitation of Lipid Droplet Volume From Light Microscopic Images With an Application to Determination of PAT Protein Density on the Droplet Surface. J Histochem Cytochem 2018; 66:447-465. [PMID: 29361239 DOI: 10.1369/0022155417753573] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Determination of lipid droplet (LD) volume has depended on direct measurement of the diameter of individual LDs, which is not possible when LDs are small or closely apposed. To overcome this problem, we describe a new method in which a volume-fluorescence relationship is determined from automated analysis of calibration samples containing well-resolved LDs. This relationship is then used to estimate total cellular droplet volume in experimental samples, where the LDs need not be individually resolved, or to determine the volumes of individual LDs. We describe quantitatively the effects of various factors, including image noise, LD crowding, and variation in LD composition on the accuracy of this method. We then demonstrate this method by utilizing it to address a scientifically interesting question, to determine the density of green fluorescent protein (GFP)-tagged Perilipin-Adipocyte-Tail (PAT) proteins on the LD surface. We find that PAT proteins cover only a minority of the LD surface, consistent with models in which they primarily serve as scaffolds for binding of regulatory proteins and enzymes, but inconsistent with models in which their major function is to sterically block access to the droplet surface.
Collapse
Affiliation(s)
- Selma Y Dejgaard
- Department of Medical Biology, Near East University, Nicosia, Cyprus
| | - John F Presley
- Department of Anatomy and Cell Biology, McGill University, Montreal, Québec, Canada
| |
Collapse
|
4
|
Wallstab C, Eleftheriadou D, Schulz T, Damm G, Seehofer D, Borlak J, Holzhütter HG, Berndt N. A unifying mathematical model of lipid droplet metabolism reveals key molecular players in the development of hepatic steatosis. FEBS J 2017; 284:3245-3261. [PMID: 28763157 DOI: 10.1111/febs.14189] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 06/02/2017] [Accepted: 07/28/2017] [Indexed: 12/16/2022]
Abstract
The liver responds to elevated plasma concentrations of free fatty acids (FFAs) with an enhanced uptake of FFAs and their esterification to triacylglycerol (TAG). On the long term, this may result in massive hepatic TAG accumulation called steatosis hepatitis. In hepatocytes, the poor water-soluble TAG is packed in specialized organelles: Lipid droplets (LDs) serving as transient cellular deposit and lipoproteins (LPs) transporting TAG and cholesterol esters to extra-hepatic tissues. The dynamics of these organelles is controlled by a variety of regulatory surface proteins (RSPs). Assembly and export of VLDLs are mainly regulated by the microsomal transfer protein (MTP) and apoprotein B100. Formation and lipolysis of LDs are regulated by several RSPs. The best studied regulators belong to the PAT (Perilipin/Adipophilin/TIP47) and CIDE families. Knockdown or overexpression of SRPs may significantly affect the total number and size distribution of LDs. Intriguingly, a large cell-to-cell heterogeneity with respect to the number and size of LDs has been found in various cell types including hepatocytes. These findings suggest that the extent of cellular lipid accumulation is determined not only by the imbalance between lipid supply and utilization but also by variations in the expression of RSPs and metabolic enzymes. To better understand the relative regulatory impact of individual processes involved in the cellular TAG turnover, we developed a comprehensive kinetic model encompassing the pathways of the fatty acid and triglyceride metabolism and the main molecular processes governing the dynamics of LDs. The model was parametrized such that a large number of experimental in vitro and in vivo findings are correctly recapitulated. A control analysis of the model revealed that variations in the activity of FFA uptake, diacylglycerol acyltransferase (DGAT) 2, and adipose triglyceride lipase (ATGL) have the strongest influence on the cellular TAG level. We used the model to simulate LD size distributions in human hepatoma cells and hepatocytes exposed to a challenge with FFAs. A random fold change by a factor of about two in the activity of RSPs was sufficient to reproduce the large diversity of droplet size distributions observed in individual cells. Under the premise that the same extent of variability of RSPs holds for the intact organ, our model predicts variations in the TAG content of individual hepatocytes by a factor of about 3-6 depending on the nutritional regime. Taken together, our modeling approach integrates numerous experimental findings on individual processes in the cellular TAG metabolism and LD dynamics metabolism to a consistent state-of-the-art dynamic network model that can be used to study how changes in the external conditions or systemic parameters will affect the TAG content of hepatocytes.
Collapse
Affiliation(s)
- Christin Wallstab
- Institute of Biochemistry, Computational Systems Biochemistry Group, Charite - University Medicine Berlin, Germany
| | - Dimitra Eleftheriadou
- Institute of Biochemistry, Computational Systems Biochemistry Group, Charite - University Medicine Berlin, Germany
| | - Theresa Schulz
- Clinic for General-, Visceral- and Transplantation Surgery, Charite - University Medicine Berlin, Germany
| | - Georg Damm
- Clinic for General-, Visceral- and Transplantation Surgery, Charite - University Medicine Berlin, Germany.,Department of Hepatobiliary Surgery and Visceral Transplantation, University of Leipzig, Germany
| | - Daniel Seehofer
- Clinic for General-, Visceral- and Transplantation Surgery, Charite - University Medicine Berlin, Germany.,Department of Hepatobiliary Surgery and Visceral Transplantation, University of Leipzig, Germany
| | - Jürgen Borlak
- Centre for Pharmacology and Toxicology, Institute for Pharmaco- and Toxicogenomics, Hannover Medical School, Hannover, Germany
| | - Hermann-Georg Holzhütter
- Institute of Biochemistry, Computational Systems Biochemistry Group, Charite - University Medicine Berlin, Germany
| | - Nikolaus Berndt
- Institute of Biochemistry, Computational Systems Biochemistry Group, Charite - University Medicine Berlin, Germany
| |
Collapse
|
5
|
El-Ekiaby NM, Mekky RY, Riad SE, Elhelw DS, El-Sayed M, Esmat G, Abdelaziz AI. miR-148a and miR-30a limit HCV-dependent suppression of the lipid droplet protein, ADRP, in HCV infected cell models. J Med Virol 2017; 89:653-659. [PMID: 27591428 DOI: 10.1002/jmv.24677] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2016] [Indexed: 02/05/2023]
Abstract
Hepatitis C Virus (HCV) promotes lipid droplet (LD) formation and perturbs the expression of the LD associated PAT proteins ADRP and TIP47, to promote its own lifecycle. HCV enhances TIP47 and suppresses ADRP by displacing it from LD surface in infected cell models. We have previously shown that suppression of TIP47 by miR-148a and miR-30a decreased intracellular LDs and HCV RNA. Thus, this study aimed at examining whether this microRNA-mediated suppression of HCV would limit HCV-dependent displacement of ADRP from LDs. ADRP expression was examined in 21 HCV-infected liver biopsies and 9 healthy donor liver tissues as well as in HCV-infected Huh7 cells using qRT-PCR. miR-148a and miR-30a expression was manipulated using specific oligos in JFH-1 infected, oleic acid treated cells, to study their impact on ADRP expression using qRT-PCR, and immunofluorescence microscopy. Intracellular HCV RNA was assessed using qRT-PCR. ADRP is down regulated in patients as well as HCVcc-JFH-I infected cell models. Forcing the expression of both miRNAs induced ADRP on the mRNA and protein levels. This study shows that HCV suppresses hepatic ADRP expression in infected patients and cell lines. Forcing the expression of miR-148a and miR-30a limits the suppressive effect of HCV on ADRP. J. Med. Virol. 89:653-659, 2017. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Nada M El-Ekiaby
- Department of Pharmacology and Toxicology, Molecular Pathology Research Group, German University in Cairo, New Cairo City-Main Entrance Al Tagamoa Al Khames, Cairo, Egypt
- Scientific Affairs Unit, Egyptian Company for Biological Sciences, Giza, Egypt
| | - Radwa Y Mekky
- Department of Pharmacology and Toxicology, Molecular Pathology Research Group, German University in Cairo, New Cairo City-Main Entrance Al Tagamoa Al Khames, Cairo, Egypt
- Faculty of Biotechnology, October University of Modern Sciences and Arts, Giza, Egypt
| | - Sarah E Riad
- Department of Pharmacology and Toxicology, Molecular Pathology Research Group, German University in Cairo, New Cairo City-Main Entrance Al Tagamoa Al Khames, Cairo, Egypt
| | - Dalia S Elhelw
- Department of Pharmacology and Toxicology, Molecular Pathology Research Group, German University in Cairo, New Cairo City-Main Entrance Al Tagamoa Al Khames, Cairo, Egypt
| | | | - Gamal Esmat
- Endemic Medicine and Hepatology, Cairo University, Cairo, Egypt
| | - Ahmed I Abdelaziz
- Department of Pharmacology and Toxicology, Molecular Pathology Research Group, German University in Cairo, New Cairo City-Main Entrance Al Tagamoa Al Khames, Cairo, Egypt
- Biotechnology Graduate Program, American University in Cairo, AUC Avenue, New Cairo, Cairo, Egypt
| |
Collapse
|
6
|
Kamili A, Roslan N, Frost S, Cantrill LC, Wang D, Della-Franca A, Bright RK, Groblewski GE, Straub BK, Hoy AJ, Chen Y, Byrne JA. TPD52 expression increases neutral lipid storage within cultured cells. J Cell Sci 2015; 128:3223-38. [PMID: 26183179 DOI: 10.1242/jcs.167692] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 07/10/2015] [Indexed: 12/12/2022] Open
Abstract
Tumor protein D52 (TPD52) is amplified and/or overexpressed in cancers of diverse cellular origins. Altered cellular metabolism (including lipogenesis) is a hallmark of cancer development, and protein-protein associations between TPD52 and known regulators of lipid storage, and differential TPD52 expression in obese versus non-obese adipose tissue, suggest that TPD52 might regulate cellular lipid metabolism. We found increased lipid droplet numbers in BALB/c 3T3 cell lines stably expressing TPD52, compared with control and TPD52L1-expressing cell lines. TPD52-expressing 3T3 cells showed increased fatty acid storage in triglyceride (from both de novo synthesis and uptake) and formed greater numbers of lipid droplets upon oleic acid supplementation than control cells. TPD52 colocalised with Golgi, but not endoplasmic reticulum (ER), markers and also showed partial colocalisation with lipid droplets coated with ADRP (also known as PLIN2), with a proportion of TPD52 being detected in the lipid droplet fraction. Direct interactions between ADRP and TPD52, but not TPD52L1, were demonstrated using the yeast two-hybrid system, with ADRP-TPD52 interactions confirmed using GST pulldown assays. Our findings uncover a new isoform-specific role for TPD52 in promoting intracellular lipid storage, which might be relevant to TPD52 overexpression in cancer.
Collapse
Affiliation(s)
- Alvin Kamili
- Molecular Oncology Laboratory, Children's Cancer Research Unit, Kids Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Nuruliza Roslan
- Molecular Oncology Laboratory, Children's Cancer Research Unit, Kids Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia Discipline of Paediatrics and Child Health, University of Sydney, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Sarah Frost
- Molecular Oncology Laboratory, Children's Cancer Research Unit, Kids Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia Discipline of Paediatrics and Child Health, University of Sydney, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Laurence C Cantrill
- Discipline of Paediatrics and Child Health, University of Sydney, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia Kids Research Institute Microscope Facility, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Dongwei Wang
- Kids Research Institute Microscope Facility, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Austin Della-Franca
- Molecular Oncology Laboratory, Children's Cancer Research Unit, Kids Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia Discipline of Paediatrics and Child Health, University of Sydney, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Robert K Bright
- Department of Immunology and Molecular Microbiology and TTUHSC Cancer Center, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Guy E Groblewski
- Department of Nutritional Sciences, University of Wisconsin, Madison, WI 53706, USA
| | - Beate K Straub
- Department of General Pathology, Institute of Pathology, Heidelberg 69120, Germany
| | - Andrew J Hoy
- Discipline of Physiology, School of Medical Sciences and Bosch Institute and Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Yuyan Chen
- Molecular Oncology Laboratory, Children's Cancer Research Unit, Kids Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia Discipline of Paediatrics and Child Health, University of Sydney, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Jennifer A Byrne
- Molecular Oncology Laboratory, Children's Cancer Research Unit, Kids Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia Discipline of Paediatrics and Child Health, University of Sydney, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| |
Collapse
|