IF twice-weekly subcutaneous 2-hydroxypropyl-β-cyclodextrin (HPβCD; 4000 mg/kg) combined with daily oral GW3965 (30 mg/kg) is administered for 8 weeks to 52-week-old male ApoE-/- mice carrying 24 weeks of Western-diet-established atherosclerotic plaques,

THEN aortic root 7-ketocholesterol (7KC) content will be reduced by ≥40% more than HPβCD monotherapy (primary endpoint: nmol 7KC/mg protein by LC-MS/MS), accompanied by elevated fecal bile acid excretion and minimal rise in hepatic 7KC, with intra-plaque-injected deuterium-labeled d7-7KC tracer appearing predominantly in feces rather than liver at week 8, confirming true systemic elimination over hepatic redistribution,

BECAUSE the two agents resolve sequential, pharmacologically distinct bottlenecks in a four-node elimination pipeline that neither agent alone can complete:

1. HPβCD physically solubilizes crystalline 7KC entrapped within plaque macrophage lysosomes and simultaneously activates Transcription Factor EB (TFEB), triggering a CLEAR-network transcriptional program that upregulates autophagic flux and lysosomal biogenesis, mobilizing sequestered 7KC from the lysosomal lumen into the cytosol and toward the inner plasma membrane leaflet (HPβCD activates TFEB-mediated autophagy to promote cholesterol clearance)[https://doi.org/10.1074/jbc.m113.506246]; (subcutaneous HPβCD dissolves cholesterol crystals in established murine plaques and drives macrophage reprogramming)[https://doi.org/10.1126/scitranslmed.aad6100].

2. [Critical bottleneck — Node 2] HPβCD monotherapy fails to complete this efflux because it does not upregulate the canonical transporter ABCA1 or ABCG1; mobilized cholesterol therefore accumulates at the cytoplasmic face of the plasma membrane, visible as increased filipin fluorescence, but cannot be exported to extracellular ApoA-I acceptors (lack of ABCA1/ABCG1 upregulation explains why HPβCD-treated cells show net increase in filipin-detectable cholesterol rather than elimination)[https://doi.org/10.1038/s41598-017-02387-8]. This is the pharmacological gap that converts HPβCD from a redistribution agent into a true elimination agent only when paired with a transporter-inducing co-treatment.

3. GW3965 resolves this bottleneck by acting as a full LXR agonist, transcriptionally upregulating Abca1 and Abcg1 in plaque macrophages, providing the transmembrane efflux channels necessary to transfer the HPβCD-mobilized intracellular 7KC pool to ApoA-I and nascent HDL particles in the subendothelial space, completing the cytoplasmic-to-extracellular transport step that cyclodextrin alone cannot supply.

4. Effluxed 7KC loaded onto HDL is delivered to the liver, where hepatic 7α-hydroxycholesterol — a CYP7A1 activity marker and bile acid synthesis intermediate — is specifically increased by HPβCD treatment, indicating that HPβCD pre-activates the hepatic oxysterol catabolic pathway before the lipid cargo arrives (HPβCD in LDLR-/- mice strongly increases hepatic campesterol...

SENS category: LysoSENS

Key references: • doi.org/10.1074/jbc.m113.506246]; • doi.org/10.1126/scitranslmed.aad6100]. • doi.org/10.1038/s41598-017-02387-8]. • doi.org/10.3390/ijms160921056]. • doi.org/10.1038/s41598-017-02387-8],