Platelet factor-4 (PF4) drives monocyte pyroptosis and cardiac remodeling in uremic cardiomyopathy via hematopoietic caspase-1.
Background
Cardiovascular disease (CVD) is the leading cause of mortality in end-stage renal disease (ESRD). While platelet activation and monocyte inflammation are recognized hallmarks of uremia, the precise mechanisms by which platelet-derived factors contribute to monocyte-mediated cardiac remodeling have remained unclear. This study addresses the critical gap in understanding how platelet factor-4 (PF4), a chemokine released by activated platelets, specifically drives monocyte pyroptosis and its subsequent role in the progression of uremic cardiomyopathy.
Study Design
Researchers established a uremic mouse model via 5/6 nephrectomy (Nx). They identified differentially expressed genes in Ly6C⁺ and Ly6C⁻ monocyte subsets using microarray and WGCNA. To assess PF4's role, mice received systemic administration of PF4 (dose not specified) with or without CXCR3 inhibition or PF4 neutralization. Caspase-1 activation was measured via FAM-FLICA staining and IL-1β ELISA. The study also utilized global Casp1⁻/⁻ mice and performed bone marrow (BM) transfer experiments to pinpoint the role of hematopoietic caspase-1.
Results
In uremic mice, circulating Ly6C⁺ monocytes decreased time-dependently. Bioinformatics analysis identified Pf4 as a key hub gene, with six pyroptosis-associated genes significantly upregulated in Ly6C⁺ monocytes compared to sham controls. Systemic PF4 infusion, acting at least partly through CXCR3, demonstrably shortened Ly6C⁺ monocyte lifespan, upregulated pyroptosis-related genes, and increased active caspase-1⁺ cells and IL-1β release. Critically, PF4 infusion also accelerated cardiac dysfunction and fibrosis. CXCR3 inhibition or PF4 neutralization effectively attenuated these detrimental effects. Global Casp1 knockout, which maintained intact Casp11 expression, provided significant protection against PF4-exacerbated cardiac injury.
Bone marrow transplantation from
Casp1⁻/⁻mice into wild-type recipients conferred the same protective phenotype, definitively identifying BM-derived caspase-1 as a key driver of this pathological process.
Key Findings
- Circulating
Ly6C⁺monocytes decreased time-dependently in uremic mice. Pf4was identified as a key hub gene, with six pyroptosis-related genes upregulated inLy6C⁺monocytes.- PF4 infusion, partly via
CXCR3, shortenedLy6C⁺monocyte lifespan and increasedcaspase-1⁺cells andIL-1βrelease. - PF4 accelerated cardiac dysfunction and fibrosis, effects attenuated by
CXCR3inhibition or PF4 neutralization. - Global
Casp1knockout andCasp1⁻/⁻bone marrow transfer protected against PF4-exacerbated cardiac injury.
Why It Matters
This research uncovers a novel and critical platelet-monocyte pyroptotic axis in the pathogenesis of uremic cardiomyopathy, offering a new therapeutic target beyond traditional approaches. For clinicians and researchers, understanding that PF4 drives caspase-1-dependent pyroptosis in Ly6C⁺ monocytes provides a mechanistic rationale for interventions. This suggests that strategies targeting PF4, CXCR3, or specifically hematopoietic caspase-1 could potentially mitigate heart failure progression in ESRD patients. While preclinical, this work lays the groundwork for developing novel pharmacological agents or cell-based therapies to interrupt this destructive inflammatory pathway, moving us closer to a usable protocol for preventing or treating cardiac complications in kidney disease.
platelet-factor-4
pf4
uremic-cardiomyopathy
esrd
pyroptosis
monocyte-inflammation