Endothelial c-IAP2 loss amplifies P2X7R inflammation, worsening schistosomiasis-associated pulmonary hypertension.
Background
Schistosomiasis-associated pulmonary hypertension (Sch-PH) is the most common Group I PH globally, characterized by significant lung endothelial cell (EC) dysfunction and microvascular apoptosis. Current understanding points to gut and lung microbiome dysbiosis, but the precise role of pro-/anti-apoptotic sensors like c-IAP2 and the purinergic receptor P2X7 (P2X7R) in this EC dysfunction remained unclear. This gap hinders targeted therapeutic development for this life-threatening illness.
Study Design
Researchers used a Cdh5cre-ERT2;cIAP1-/-;cIAP2fl/fl animal model to investigate endothelial c-IAP2's contribution to Sch-PH. Mice underwent an IP/IV-Egg challenge to induce PH-like features. They also pharmacologically inhibited P2X7R function to confirm its role. Primary endpoints included echocardiography for pulmonary acceleration time (PAT), PAT/pulmonary ejection time, and right ventricular free wall thickness (RVFWTH), alongside assessments of lung EC death and P2X7R expression.
Results
Genetic ablation of endothelial c-IAP2 expression was sufficient to induce PH-like features in mice after IP/IV-Egg challenge, with echocardiography indicating higher PAT, PAT/pulmonary ejection time, and RVFWTH compared to controls. This effect was notably linked to the female prevalence of the disease.
Pharmacological inhibition of P2X7R function confirmed its critical role in promoting lung EC death and disease progression in Sch-PH. Data suggest that microbiome-associated metabolic alterations in Sch-PH are linked to microvascular EC apoptosis, driven by
ATP/P2X7Roveractivation and suppressed c-IAP2 expression. PulmonaryP2X7Roverexpression was identified as a putative target in the onset of Sch-PH pathology.
Key Findings
- Genetic ablation of endothelial c-IAP2 induced PH-like features in mice after egg challenge.
- Echocardiography showed higher PAT, PAT/pulmonary ejection time, and RVFWTH in c-IAP2-deficient mice.
- Pharmacological P2X7R inhibition reduced lung endothelial cell death and disease progression.
- Microbiome-linked metabolic changes drive EC apoptosis via ATP/P2X7R overactivation and c-IAP2 suppression.
- Pulmonary P2X7R overexpression is a putative target in Sch-PH onset, linked to female prevalence.
Why It Matters
This study highlights endothelial c-IAP2 and P2X7R as promising therapeutic targets for Sch-PH, particularly given its sex-linked pathology. Understanding that c-IAP2 loss amplifies P2X7R-driven inflammation provides a novel mechanistic pathway for intervention. For clinicians, this suggests potential for P2X7R inhibitors or strategies to restore c-IAP2 function to mitigate disease progression. While preclinical, these findings lay the groundwork for developing targeted therapies beyond current standards, potentially offering a more precise approach to manage this common and severe form of PH.
schistosomiasis
pulmonary-hypertension
p2x7r
c-iap2
endothelial-dysfunction
inflammation