Targeting ZIP12-mediated Zn ²⁺ signaling as a treatment for pulmonary hypertension

ZIP12, a membrane-bound zinc importer, is up-regulated in the remodeled pulmonary arterioles of patients with pulmonary arterial hypertension (PAH). Genetic deletion of its encoding gene, Slc39a12 , ameliorates the disease in rodent models. Here, we show that ZIP12 overexpression in human pulmonary artery smooth muscle cells (PASMCs) increased intracellular labile Zn ²⁺ and promoted proliferation. ZIP12 siRNA knockdown attenuated pulmonary hypertension in rodent models. We developed a humanized anti-ZIP12 monoclonal antibody, APL-9796, that normalized intracellular Zn ²⁺ concentration, suppressed proliferation in fibroblasts derived from patients with PAH and PDGF-stimulated PASMCs, and reduced PDGF-induced cytoskeletal remodeling in PASMCs and contractility in PASMCs and engineered pulmonary artery tissues. APL-9796 showed dose-dependent efficacy in humanized Slc39a12 rats, improving cardiopulmonary parameters after induction of pulmonary hypertension and was well tolerated in phase 1 clinical studies. Transcriptomic profiling revealed modulation of several molecular pathways, including those involving AMPK, PPAR, and PI3K-Akt. ZIP12-driven labile Zn ²⁺ signaling underpins the pathogenesis of PAH. Targeting ZIP12 with APL-9796 offers a promising therapeutic strategy.