Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Dec 7;23(24):15456.
doi: 10.3390/ijms232415456.

Lipid Droplet-Associated Proteins Perilipin 1 and 2: Molecular Markers of Steatosis and Microvesicular Steatotic Foci in Chronic Hepatitis C

Selina Schelbert  1   2 , Mario Schindeldecker  1 , Uta Drebber  3 , Hagen Roland Witzel  1 , Arndt Weinmann  4 , Volker Dries  3 , Peter Schirmacher  5 , Wilfried Roth  1 , Beate Katharina Straub  1
Affiliations

Lipid Droplet-Associated Proteins Perilipin 1 and 2: Molecular Markers of Steatosis and Microvesicular Steatotic Foci in Chronic Hepatitis C

Selina Schelbert et al. Int J Mol Sci. .

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.

Keywords: PAT proteins; focal fatty change; hepatitis B virus (HBV); hepatitis C virus (HCV); non-alcoholic steatohepatitis (NASH).

PubMed Disclaimer

Conflict of interest statement

B.K.S. has taken part in an advisory board of Bayer Healthcare concerning radiology of hepatocellular carcinoma. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Immunofluorescence microscopy of LDs and perilipins in the liver. (a,b) Confocal laser scanning fluorescence microscopy of perilipin 2 ((a), PLIN 2, green) and perilipin 1 ((b), PLIN1, green) mark LDs in desmin (red)-positive, non-parenchymal HSC in cryopreserved normal bovine liver. Note absence of perilipin 1 and 2-positive LDs in parenchymal cells of normal bovine liver. (c) Perilipin 3 (PLIN3, green) localizes to the rim of Nile red (red)-positive LDs in oleate-treated cultured cells of the HCC-derived line PLC. (d–f) Accumulation of Nile red (red)-positive LDs in human NAFLD is attributed to fatty change in hepatocytes ((e), CK8, green), whereas HSC ((d), vimentin, green) show no Nile red-positive LDs. As an example, perilipin 1 (PLIN1, red) localizes to LDs in CK8 (green)-positive hepatocytes, but not to vimentin (blue)-positive HSC. Merge images in (a,b,d,e) include differential interfering contrast. Scale cars: each 25 µm.
Figure 2
Figure 2
Perilipin 2 immunohistochemistry demonstrates different degrees of steatosis in chronic hepatitis C in relation to HCV genotype. (a) Representative immunohistochemical perilipin 2 (PLIN2) stains from a collection of 231 liver biopsies of patients with chronic hepatitis C with respect to the different HCV genotypes 1a,1b,2b,3a and 4. The arrow depicts perilipin-2 positivity in an HSC. (b) Correlation of the degree of steatosis as determined by conventional H&E stain with respect to the HCV genotypes (boxplot). Wilcoxon test with p = 0.014. p-values < 0.05 (*) were considered significant. Scale bar = 100 µm. n = numbers of cases evaluated per genotype.
Figure 3
Figure 3
Appearance of perilipin-positive microvesicular steatotic foci with chronic hepatitis C infections. (a) Overview of representative immunohistochemical stains for perilipin 2 (PLIN2) in liver biopsies from 3 different HCV patients with no (P1), minor (P2) and a moderate (P3) degree of steatosis. Arrows indicate perilipin 2-positive steatotic foci. Scale bar: 100 µm. (b) Higher magnification of the liver biopsies of the same patients with respective immunohistochemical stains for perilipins 1 and 2 as well as PAS staining. Scale bar = 100 µm. (c,d) Occurrence of steatotic foci with respect to the degree of steatosis (boxplot). Foci were identified by perilipin 2 (c) or H&E staining (d). Wilcoxon test with p < 0.05 (*) were considered significant.
Figure 4
Figure 4
Perilipin-positive microvesicular steatotic foci do not overlap with virus-infected clusters and may also be found in other chronic liver diseases. (a) Immunohistochemical analysis of perilipins 1 and 2, and hepatitis B surface antigen (HBs) in consecutive sections of liver biopsies with chronic hepatitis B. Steatotic foci with (upper panel) or without (lower panel) detectable HBs-Ag positive clusters are shown. (b) Immunohistochemistry for perilipins 1 and 2 as well as PAS stain of consecutive liver sections from a patient with autoimmune hepatitis. (c) Immunohistochemistry for perilipin 1, perilipin 2, glutamine synthetase and Ki67 as well as PAS and H&E stain of consecutive sections from a liver operation specimen from a patient with liver metastasis with a neuroendocrine tumor. (d) Transmission electron microscopy of steatotic focus shown in (c). The dashed line (left panel) indicates the boundary of the focus. Scale bar = 10 µm.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. MacSween R., Burt A. Histologic Spectrum of Alcoholic Liver Disease. Semin. Liver Dis. 1986;6:221–232. doi: 10.1055/s-2008-1040605. - DOI - PubMed
    1. Lieber C. Mechanism of ethanol induced hepatic injury. Pharmacol. Ther. 1990;46:1–41. doi: 10.1016/0163-7258(90)90032-W. - DOI - PubMed
    1. Goodman Z.D., Ishak K.G. Histopathology of Hepatitis C Virus Infection. Semin. Liver Dis. 1995;15:70–81. doi: 10.1055/s-2007-1007264. - DOI - PubMed
    1. Gluchowski N.L., Becuwe M., Walther T.C., Farese R.V., Jr. Lipid droplets and liver disease: From basic biology to clinical implica-tions. Nat. Rev. Gastroenterol. Hepatol. 2017;14:343–355. doi: 10.1038/nrgastro.2017.32. - DOI - PMC - PubMed
    1. Younossi Z.M., Stepanova M., Younossi Y., Golabi P., Mishra A., Rafiq N., Henry L. Epidemiology of chronic liver diseases in the USA in the past three decades. Gut. 2019;69:564–568. doi: 10.1136/gutjnl-2019-318813. - DOI - PubMed

Grants and funding

This research was funded by grants of the DFG to B.K.S. (STR 1160/1-1 and 1-2).