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Immortal activated human hepatic stellate cells generated by ectopic telomerase expression
Bernd Schnabl1, Youkyung Hwang Choi, John C Olsen
1Departments of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Summary
Introducing human telomerase reverse transcriptase (hTERT) into hepatic stellate cells (HSCs) immortalizes them, maintaining their activated phenotype. This creates a valuable tool for studying HSC biology in culture.
Area of Science:
- Cell Biology
- Molecular Biology
- Gastroenterology
Background:
- Telomere shortening triggers cellular senescence.
- Human telomerase reverse transcriptase (hTERT) stabilizes telomeres and extends cell lifespan.
- Hepatic stellate cells (HSCs) play a role in liver physiology and pathology.
Purpose of the Study:
- To investigate the role of telomerase activity and telomere maintenance in activated human HSC proliferation.
- To establish an immortal human HSC cell line for research purposes.
Main Methods:
- Human HSCs were isolated and infected with a retrovirus expressing hTERT.
- Telomerase activity and telomere length were assessed.
- Cell proliferation, senescence, and phenotype were analyzed using various techniques including microarray and RT-PCR.
- Control HSCs received a vector without hTERT.
Main Results:
- Ectopic hTERT expression restored telomerase activity and maintained telomere length in HSCs.
- Telomerase-negative HSCs senesced after 9-15 passages, while hTERT-expressing HSCs underwent over 69 passages.
- hTERT-expressing HSCs maintained an activated phenotype without oncogenic transformation.
- Gene expression patterns in immortalized HSCs resembled those of activated HSCs.
Conclusions:
- Introduction of hTERT into activated human HSCs leads to their immortalization and sustained activated phenotype.
- The developed immortalized HSC line serves as a valuable model for studying human HSC biology.
- Telomere maintenance is crucial for the long-term proliferation of activated human HSCs.