Human Adipose-Derived Stem Cells for Hepatitis C Virus Propagation
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Solution Overview
Problem
Current in vitro systems for propagating hepatitis C virus (HCV) are limited, particularly for extrahepatic replication, due to the difficulty in maintaining primary human hepatocytes and the reliance on molecular clones rather than natural virus, which raises concerns about the validity of clinical virus-host interaction models.
Innovation Solution
A human adipose-derived stem cells (hADSCs)-based system for propagating HCV, using hADSCs, culture medium suitable for culturing hADSCs, and HCV derived from infected individuals or clinical isolates, supporting complete replication and production of infectious virus across various genotypes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If primary human hepatocytes are used for HCV propagation, then the model reflects actual clinical virus-host interaction, but the cells are difficult to maintain in culture and show significant donor-to-donor variations
Solution Approach 1:
The patent uses molecular clones (HCVcc) as an intermediary system that can be propagated in easy-to-maintain cell lines (Huh7.5) while still representing clinical HCV. This intermediary approach allows researchers to work with a reliable, reproducible viral system that captures essential features of clinical HCV without the maintenance difficulties of primary hepatocytes.
Solution Approach 2:
The patent creates copies of clinical HCV strains through molecular cloning techniques, generating viral clones that can be propagated in standardized cell lines. These viral copies retain the genetic and functional characteristics of the original clinical isolates while enabling consistent, reproducible experiments without donor variation.
2Ease of operation
If molecular clones are used for HCV propagation, then the virus can be propagated in easy-to-maintain cell lines, but concerns arise about how far the data can be extrapolated to actual clinical virus
Solution Approach 1:
The patent performs preliminary characterization of molecular clones to ensure they retain key features of clinical HCV before using them for experiments. This includes verifying that the clones can infect primary hepatocytes and exhibit clinical-relevant phenotypes, thereby establishing their validity as models for clinical virus studies.
Solution Approach 2:
The patent employs feedback mechanisms by using molecular clones to study HCV and then validating findings against clinical observations and primary hepatocyte data. This iterative process ensures that data from simplified models remains relevant to clinical virus behavior, allowing continuous refinement of the model's accuracy.
3Reliability
If clinical HCV isolates are used directly in in vitro systems, then the model reflects actual clinical virus, but suitable in vitro systems for extrahepatic replication are severely limited
Solution Approach 1:
The patent develops a universal in vitro system using molecular clones that can be propagated in multiple cell types including hepatoma cell lines and primary hepatocytes. This multi-functional system allows the same viral clone to be used for studying both hepatic and extrahepatic replication, expanding the versatility of in vitro HCV models while maintaining clinical relevance.
Data Source
AI summary
Hepatitis C virus replication at extrahepatic sites has been suggested; however, complete viral replication has only been confirmed in hepatocytes. Here we show that human adipogenic DLK-1+ stem cells (hADSC) freshly isolated from HCV-infected individuals contained viral transcripts, replication intermediates and viral antigens in vivo, and viral transcripts increased in supernatants upon prolonged ex vivo culture. Furthermore, naive hADSC isolated from HCV (−) individuals support complete replication of clinical isolates in vitro, and the infection is donor-nonspecific for cells and cross-genotypic for viruses. Viral infection/replication is mediated through CD81, LDL-R, SR-B1, EGFR, Apolipoprotein E, occludin, claudin-1, NPC1L1 and diacylglycerol acetyltransferase-1, and can be inhibited by anti-viral drugs. In addition, the physical properties of hADSC-propagated viral particles resemble clinical isolates more than JFH1/HCVcc, and viruses propagated by in vitro infected hADSC are infectious to primary human hepatocytes. Therefore, hADSC are an in vivo HCV reservoir and represent a novel venue of clinical virus-host interaction. hADSC can also be exploited as a physiologically relevant primary cell culture system to propagate clinical isolates.