Microvascular endothelial scavenger receptor class B type I protects against heart failure with preserved ejection fraction by inhibiting T-cell cardiotropism

Here we find that scavenger receptor class B type I (SR-B1) is predominantly expressed in CMECs and decreased significantly in HFpEF. Endothelial-specific SR-B1 deficiency exacerbates cardiac pathological remodeling and diastolic dysfunction in HFpEF, which can be prevented by endothelial SR-B1 reconstitution through adeno-associated virus serotype 1 (AAV1)-mediated delivery in endothelial-specific SR-B1-deficient mice.

Single-cardiac-endothelial-cell transcriptomics and lineage-tracing system reveal that inflammatory CMECs subcluster activation is responsible for the deteriorating HFpEF progression induced by endothelial SR-B1 loss, rather than endothelial-to-mesenchymal transition. Mechanistically, SR-B1 loss drives increased CXCL10 secretion, which orchestrates CMECs activation and CXCR3-positive T-cell cardiotropism to promote diastolic dysfunction—a process associated with endothelial IRF1 activation.