Myoblast Isolation Using Small Molecule Differentiation

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Solution Overview

Problem

Current methods for deriving myoblasts from human induced pluripotent stem cells (hiPSCs) for muscular dystrophy modeling are inefficient, relying on viral gene delivery and animal-derived factors, which can introduce random integration and mask disease phenotypes, and require long-term culture, lacking a strategy for isolating high-purity, expandable, and functional myoblasts to study disease-specific transcriptional profiles and functional deficits.

Innovation Solution

A method involving reprogramming patient fibroblasts into hiPSCs, directing them into myoblasts using CHIR99021 and DAPT, and selecting purified myoblasts with NCAM(5.H1) and HNK1 antibodies, followed by treatment with dual SMAD inhibitors and a vector carrying the DYSTROPHIN gene to generate rescued myoblasts that resemble normal myoblasts, enabling the creation of patient-specific DMD model systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If viral gene delivery is used to derive myoblasts from hPSCs, then myogenic cells can be produced, but random integration of viral DNA can jeopardize disease modeling and mask disease phenotypes

Engineering Contradiction:

Improvemyogenic cell productionVSAvoiddisease modeling accuracy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent removes the harmful viral delivery component from the process entirely. Instead of using viral vectors to deliver myogenic transcription factors, the invention uses small molecule compounds (CHIR99021 and DAPT) to directly induce myogenic differentiation of hPSCs, thereby eliminating the risk of random viral integration while maintaining the ability to generate myoblasts

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces small molecule compounds as intermediaries to mediate the differentiation process. CHIR99021 (a GSK-3β inhibitor) and DAPT (a γ-secretase inhibitor) serve as chemical mediators that trigger the Wnt/β-catenin and Notch signaling pathways respectively, enabling myogenic differentiation without requiring viral gene delivery

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If animal-derived factors are used in differentiation protocols, then myogenic cells can be derived, but the process requires arduous long-term culture over 4 months

Engineering Contradiction:

Improvemyogenic cell derivationVSAvoidculture duration

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The patent fundamentally changes the differentiation parameters by replacing animal-derived factors with small molecule compounds. This parameter change accelerates the differentiation process from 4 months to approximately 3-4 weeks, while also simplifying the culture conditions by using defined, xeno-free media formulations

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs small molecule compounds that are stable, easily synthesized, and do not require long-term maintenance or complex preparation. These chemical reagents can be stored and used as needed, replacing the need for maintaining animal-derived factor sources over extended periods

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If ectopic expression of myogenic transcription factors is used, then certain myogenic cells can be produced, but the random integration of viral DNA can jeopardize disease modeling

Engineering Contradiction:

Improvemyogenic cell yieldVSAvoiddisease phenotype fidelity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical/genetic approach of viral transduction with a chemical signaling approach. Instead of forcing expression of myogenic transcription factors through viral integration, small molecules activate endogenous signaling pathways (Wnt and Notch) that naturally regulate myogenic differentiation, thereby preserving disease-specific genetic backgrounds

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Duration of action of moving object

If long-term culture is required for myoblast derivation, then differentiation can occur, but the process becomes arduous and inefficient

Engineering Contradiction:

Improvedifferentiation timeVSAvoidmyoblast production efficiency

Core Design Contradiction:

Duration of action of moving objectVSProductivity

Solution Approach 1:

The patent employs a staged, periodic differentiation protocol where small molecule compounds are applied in specific sequences and timeframes. CHIR99021 is used first to activate Wnt signaling and induce mesodermal commitment, followed by DAPT to block Notch signaling and promote myogenic differentiation, creating an efficient temporal sequence that accelerates the process

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS11318167B2Isolation of fusion-competent myoblasts and therapeutic applications thereof related to muscular dystrophy

Publication Date: 2022.05.03 KRIEGER KENNEDY INSTITUTE INC

AI summary

Described are methods of isolating high purity myoblasts that are used to create novel DMD model systems and methods using human induced pluripotent stem cells (hiPSCs). Also described are therapeutic methods based on the use of these myoblasts.