CD248 activates TGF-β receptor I to promote vascular remodeling in pulmonary arterial hypertension

Jones, L. I.; McIntire-Ray, H. J.; Morales, A. N.; Vang, S.; Hirsh, M. J.; Gonzalez Coba, A. J.; Matthews, E. L.; Adriatico, K. L.; Harris, N. P.; Zafar, I.; Xing, D.; Lin, V.; Tian, L.; Payne, G. A.; Ahmad, A.; Dweik, R.; Wells, J. M.; Olson, H. M.; Kyle, J.; Clair, G. C.; Krick, S.; Barnes, J.

doi:10.64898/2026.04.22.720270

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bioRxiv · 10.64898/2026.04.22.720270

CD248 activates TGF-β receptor I to promote vascular remodeling in pulmonary arterial hypertension

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Abstract

I.BackgroundPulmonary arterial hypertension (PAH) is a debilitating cardiopulmonary disease characterized by progressive remodeling of the pulmonary vasculature. Pathologic transforming growth factor-{beta} (TGF-{beta}) signaling is an essential driver of vascular remodeling in PAH. While global inhibitors of TGF-{beta} exist, their clinical application is limited by systemic adverse effects. Therefore, a critically unmet need in PAH is to identify pulmonary vascular-specific regulators of the TGF-{beta} axis, which would selectively enhance clinical efficacy while minimizing adverse effects. As the clinical care of PAH largely promotes vasodilation, and only one FDA-approved agent targets vascular remodeling, this study aimed to identify selective, therapeutically targetable regulators of the TGF-{beta} axis in the PAH pulmonary vasculature. MethodsCD248 was identified via liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomics in human lungs. CD248 levels were assessed across human, rat, and mouse lung tissues using western blotting, RTqPCR, and/or immunofluorescence techniques. CD248-null (CD248-/-) mice were used to study the contribution of CD248 to hypoxia-sugen (H/S)-induced PAH. The mechanistic role of CD248 in PAH vascular remodeling and TGF-{beta} signaling was assessed by genetic (siRNA knockdown; overexpression) and pharmacologic (Ontuxizumab) manipulation of primary human pulmonary vascular cells. ResultsLC-MS/MS proteomics coupled with pathway enrichment analysis of human lung tissue identified CD248 as a putative mediator of vascular remodeling that is elevated in PAH lungs. CD248 was elevated in PAH pulmonary artery smooth muscle cells (PASMCs) across human, rat, and mouse lung tissue. CD248-/- mice were protected from H/S-induced elevations in right ventricular (RV) systolic pressure (RVSP), RV hypertrophy, and pulmonary artery muscularization. CD248 knock-down reduced cell proliferation and migration of primary PAH PASMCs. CD248 was essential for phospho-activation of TGF-{beta} receptor I (T{beta}RI) at S165 and canonical phosphorylation of SMAD3 at S423/425. CD248 loss blunted TGF-{beta}-induced gene expression (FN1, Col11, -SMA) and activated expression of the vasoprotective matrix metalloprotease, MMP-8. Mechanistically, CD248 interacted with and enhanced de novo phosphorylation and stability of T{beta}RI, blocking its ubiquitin-mediated proteasomal degradation. Ontuxizumab promoted T{beta}RI instability and attenuated the production of FN1, Col11, and -SMA in primary PAH PASMCs. ConclusionsThis work identifies CD248 as a previously unrecognized co-activator of T{beta}RI in PAH. As CD248 is largely quiescent in most adult tissues yet pathologically upregulated in the PAH pulmonary vasculature, this study supports the potential of anti-CD248 therapy as a novel pulmonary vascular-specific alternative to systemic TGF-{beta} inhibition.

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Jones, L. I., McIntire-Ray, H. J., Morales, A. N., Vang, S., Hirsh, M. J., Gonzalez Coba, A. J., Matthews, E. L., Adriatico, K. L., Harris, N. P., Zafar, I., Xing, D., Lin, V., Tian, L., Payne, G. A., Ahmad, A., Dweik, R., Wells, J. M., Olson, H. M., Kyle, J., Clair, G. C., Krick, S., Barnes, J.. 2026-04-29. CD248 activates TGF-β receptor I to promote vascular remodeling in pulmonary arterial hypertension. https://doi.org/10.64898/2026.04.22.720270

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