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Updated: Jul 14, 2025
CRISPR/Cas9-mediated Targeted Integration In Vivo Using a Homology-mediated End Joining-based Strategy
Published on: March 12, 2018
New opportunities in the management and treatment of refractory hypercholesterolemia using in vivo CRISPR-mediated
1Integrated Pharma Solutions, Boston, USA; Northeastern University, Boston, USA.
Insights
Gene editing offers new hope for refractory hypercholesterolemia by targeting LDL receptor pathways. This approach aims to reduce LDL cholesterol levels in patients with genetic conditions like HoFH and HeFH.
Area of Science:
- Cardiovascular Genetics
- Molecular Therapeutics
- Gene Editing Technologies
Background:
- Refractory hypercholesterolemia (RH) significantly increases atherosclerotic cardiovascular disease (ASCVD) risk, particularly in patients with familial hypercholesterolemia (HoFH and HeFH).
- Current treatments like statins, ezetimibe, and PCSK9 monoclonal antibodies (mAB) show limited efficacy in HoFH and provide only modest LDL reduction in HeFH.
- ANGPTL3 mAB offers some benefit but is insufficient for achieving therapeutic LDL goals in HoFH, necessitating novel treatment strategies.
Purpose of the Study:
- To explore novel therapeutic approaches for refractory hypercholesterolemia, focusing on gene therapy and gene editing.
- To evaluate the potential of genome/base editing technologies in modulating lipid-lowering pathways.
- To address the unmet need for effective treatments in patients intolerant to high-dose statins or unresponsive to existing therapies.
Main Methods:
- Investigated adeno-associated virus (AAV)-based gene therapy in preclinical models.
- Utilized CRISPR/Cas9-mediated genome and base editing to induce gain-of-function in LDL receptors (LDLR) and loss-of-function in ANGPTL3.
- Assessed the efficacy and safety of gene editing, including off-target mutagenesis analysis.
Main Results:
- Gene editing successfully demonstrated gain-of-function in LDLR and loss-of-function in ANGPTL3 in animal models.
- CRISPR/Cas9 editing achieved significant LDL cholesterol reduction, with minimal off-target effects reported for ANGPTL3 inactivation.
- Refined genome/base editing techniques have substantially reduced off-target mutagenesis, enhancing safety profiles.
Conclusions:
- Advances in genome/base editing, coupled with insights into LDLR function and ANGPTL3 inactivation, present promising therapeutic avenues.
- These gene editing strategies offer potential for treating refractory hypercholesterolemia and reducing ASCVD risk.
- Targeting both LDLR-dependent and independent pathways via CRISPR-Cas9 holds significant promise for future clinical applications.
Aims:
Refractory hypercholesterolemia (RH), caused primarily by the loss-of-function mutation of LDL receptor (LDLR) gene seen in HoFH and HeFH patients, remains a major risk factor for atherosclerotic cardiovascular disease (ASCVD). Statin and ezetimibe combination therapy lower circulating LDL by 30% in HoFH patients. PCSK9 mAB, being an LDLR-dependent therapy, is not effective in HoFH, but lowers LDL by 25% in HeFH patients. A maximum reduction of 50% was noted in HoFH patients treated with ANGPTL3 mAB, which was not enough to achieve therapeutic goal of LDL. Therefore, new approaches are warranted to offer hopes to individuals intolerant to higher dose statins and not able to achieve recommended LDL level.
Data Synthesis:
New approaches to lower LDL include gene therapy and gene editing. AAV-based gene therapy has shown encouraging results in animal models. Using CRISPR/Cas9-mediated genome/base editing, gain of function and loss of function have been successfully done in animal models. Recent progress in the refinement of genome/base editing has overcome the issues of off-target mutagenesis with ∼1% mutagenesis in case of PCSK9 and almost no off-target mutagenesis in inactivating ANGPTL3 in animal models showing 50% reduction in cholesterol. Current approaches using CRISPR-Cas9 genome/base editing targeting LDLR-dependent and LDLR-independent pathways are underway.
Conclusions:
The new information on gain of LDLR function and inactivation of ANGPTL3 together with developments in genome/base editing technology to overcome off-target insertion and deletion mutagenesis offer hope to refractory hypercholesterolemic individuals who are at a higher risk of developing ASCVD.
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