Science · CRISPR-Cas9

CRISPR-Cas9 delivery via LNP: mechanism and design

mRNA-based LNP delivery of CRISPR components offers transient expression, no genomic integration risk, and a dose-titratable safety profile that viral vectors cannot match.

Molecular visualization of CRISPR-Cas9 ribonucleoprotein complex with guide RNA bound to target DNA strand
Delivery Mechanism

From injection to nuclear editing

01

IV Administration & ApoE Opsonization

LNP is administered intravenously. In circulation, ApoE adsorbs to the PEG-lipid corona, acting as a ligand for LDLR-mediated endocytosis in hepatocytes. This ApoE-mediated mechanism is the primary driver of hepatic selectivity.

02

Receptor-Mediated Uptake

LDLR on hepatocyte surface binds ApoE-coated LNP → clathrin-mediated endocytosis. Particle enters early endosome (pH ~6.5) then late endosome (pH ~5.0).

03

Endosomal Escape

Ionizable lipid protonates at pH 5.0. Positively charged ionizable lipid interacts with negatively charged phospholipids in the endosomal membrane → hexagonal phase transition → membrane destabilization → mRNA released into cytoplasm.

04

Translation & Editing

Released Cas9 mRNA is translated by ribosomes. Cas9 protein assembles with co-delivered guide RNA → ribonucleoprotein complex enters nucleus → target DNA cut at the guide RNA-specified locus. Expression is transient (Cas9 mRNA half-life ~8 hours in hepatocytes).

Delivery Comparison

LNP vs. AAV for in-vivo CRISPR

Property LNP (Gendelivr) AAV Lentivirus
Genomic integration risk None (mRNA, transient) Low (<1%) High (by design)
Payload capacity Unlimited ~4.7 kb (limiting for base editors) ~8 kb
Re-dosing Possible (no pre-existing immunity) Limited (anti-AAV antibodies) Not applicable
Manufacturing GMP microfluidic (scalable) Baculovirus or HEK293 (complex) HEK293 transfection (complex)
Regulatory precedent mRNA COVID vaccines, siRNA Approved products (Luxturna, Zolgensma) Approved (CAR-T products)

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