Induced Hepatic Stem Cells for Human Liver Function Evaluation
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Solution Overview
Problem
Current drug development processes are prolonged and costly due to the need for animal tests, which are limited by species differences and the scarcity and ethical issues surrounding human hepatocytes, and there is a lack of efficient methods for inducing differentiation of hepatocytes for drug discovery and regenerative medicine.
Innovation Solution
Induced hepatic stem cells are created by introducing POU5F1, KLF4, and SOX2 genes into mammalian cells, allowing them to express both embryonic stem cell and hepatocyte markers, enabling prolonged culture and use in safety, toxicity, and metabolism tests, as well as drug discovery and regenerative medicine applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If primary cultured hepatocytes are used for drug testing, then human liver function evaluation is improved, but donor scarcity and ethical issues worsen
Solution Approach 1:
The invention creates induced hepatic stem cells that copy the essential functions and characteristics of primary hepatocytes. These induced cells replicate human liver metabolic functions, enzyme activities, and physiological responses without requiring actual human hepatocyte donors, thus solving the donor scarcity problem while maintaining evaluation reliability
Solution Approach 2:
The invention changes the cellular state parameters by inducing pluripotent stem cells to differentiate into hepatic stem cells with hepatocyte-like functions. By controlling differentiation parameters and culture conditions, the invention transforms undifferentiated stem cells into functional liver cells that exhibit appropriate metabolic and physiological characteristics for drug testing
2Ease of manufacture
If animal tests are used for drug evaluation, then testing feasibility is improved, but species difference accuracy worsens
Solution Approach 1:
The invention creates human-derived induced hepatic stem cells that copy human liver physiological characteristics, replacing animal models. These cells maintain human-specific metabolic pathways, enzyme systems, and drug response patterns, enabling accurate prediction of human drug kinetics without species differences while preserving testing feasibility through in vitro culture systems
3Duration of action of stationary object
If existing cell lines are used for prolonged culture, then culture duration is improved, but hepatocyte function retention worsens
Solution Approach 1:
The invention employs dynamic culture conditions and periodic re-induction strategies to maintain hepatic stem cell functionality during prolonged culture. By adjusting culture parameters, growth factors, and differentiation cues over time, the invention prevents functional degradation that typically occurs in conventional cell lines during extended passage culture
Solution Approach 2:
The invention performs preliminary establishment of induced hepatic stem cells with robust self-renewal capabilities and hepatocyte markers before prolonged culture begins. This preliminary optimization of cell state and culture protocols ensures that cells maintain their functional characteristics throughout extended culture periods, preventing later functional loss
4Measurement precision
If more donors are used to cover individual differences, then representation accuracy is improved, but ethical issues and cost worsen
Solution Approach 1:
The invention creates universal induced hepatic stem cell lines that can be differentiated to represent multiple genetic backgrounds and individual variations. By establishing master cell banks with diverse genetic profiles that can be expanded and differentiated as needed, the invention covers individual differences without requiring continuous procurement from multiple donors, reducing management complexity and ethical concerns
Data Source
AI summary
The present invention relates to an induced hepatic stem cell defined as follows, a process for production thereof, and applications of the cell, which are useful in safety tests, toxicity tests, metabolism tests, drug interaction tests, antiviral activity tests, screening tests for pharmaceuticals such as hyperlipidemic therapeutics, hypertension therapeutics, low-molecular weight compound medicaments, and antibody medicaments, screening for targets in drug discovery, preparation of animal models, production of hepatocyte-produced proteins, and in regenerative medicine. The induced hepatic stem cell of the present invention is characterized by at least satisfying the following requirements (1)-(3): (1) it expresses at least 15 genes as selected from the group of the genes which are marker genes for an embryonic stem cell; (2) it has properties of a hepatocyte; and (3) it can be subjected to expansion culture or passage culture for at least 3 days.