Design, synthesis and optimization of pyrazolo[3,4-b] pyridine derivatives as Hsp110-STAT3 interaction disruptors for the treatment of pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a progressive and fatal cardiovascular disorder that is characterized by pulmonary vascular remodeling. Our previous results demonstrated that heat shock protein (Hsp110) was significantly activated to induce vascular remodeling by enhancing the Hsp110-STAT3 interaction. The development of inhibitors that disrupt this association represents a novel strategy for the treatment of PAH. This study is committed to finding new inhibitors targeting the Hsp110-STAT3 interaction based on the structure of the lead compound 2h. A fusion design principle was employed in conjunction with structural optimization in the identification of the compound 10b. In vitro data indicates that 10b exhibited greater potency in the inhibition of pulmonary vascular cells malignant phenotypes via impeding the chaperone function of Hsp110 and the Hsp110-STAT3 interaction. In hypoxia-induced PAH rats, administration of 10b significantly attenuated vascular remodeling and right ventricular hypertrophy by inhibiting the Hsp110-STAT3 association. In short, this work identified a novel and promising lead compound for the development of anti-PAH drugs targeting the Hsp110-STAT3 interaction.

Allosteric site identification, virtual screening and discovery of a sulfonamide Hsp110-STAT3 interaction inhibitor for the treatment of hypoxic pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a severe pulmonary vascular disorder marked by vascular remodeling, which is linked to the malignant phenotypes of pulmonary vascular cells. The prevailing therapeutic approaches for PAH tend to neglect the potential role of vascular remodeling, leading to the clinical prognosis remains poor. Previously, we first demonstrated that heat shock protein (Hsp110) was significantly activated to boost Hsp110-STAT3 interaction, which resulted in abnormal proliferation and migration of human pulmonary arterial endothelial cells (HPAECs) under hypoxia. In the present study, we initially postulated the allosteric site of Hsp110, performed a virtual screening and biological evaluation studies to discover novel Hsp110-STAT3 interaction inhibitors. Here, we identified compound 29 (AN-329/43448068) as the effective inhibitor of HPAECs proliferation and the Hsp110-STAT3 association with good druggability. In vitro, 29 significantly impeded the chaperone function of Hsp110 and the malignant phenotypes of HPAECs. In vivo, 29 remarkably attenuated pulmonary vascular remodeling and right ventricular hypertrophy in hypoxia-induced PAH rats (i.g). Altogether, our data support the conclusion that it not only provides a novel lead compound but also presents a promising approach for subsequent inhibitor development targeting Hsp110-STAT3 interaction.

Discovery and Optimization of Hsp110 and sGC Dual-Target Regulators for the Treatment of Pulmonary Arterial Hypertension.

Currently, bifunctional agents with vasodilation and ameliorated vascular remodeling effects provide more advantages for the treatment of pulmonary arterial hypertension (PAH). In this study, we first screened the hit 1 with heat shock protein 110 (Hsp110) inhibition effect from our in-house compound library with soluble guanylate cyclase (sGC) activity. Subsequently, a series of novel bisamide derivatives were designed and synthesized as Hsp110/sGC dual-target regulators based on hit 1. Among them, 17i exhibited optimal Hsp110 and sGC molecular activities as well as remarkable cell malignant phenotypes inhibitory and vasodilatory effects in vitro. Moreover, compared to riociguat, 17i showed superior efficacy in attenuating pulmonary vascular remodeling and right ventricular hypertrophy via Hsp110 suppression in hypoxia-induced PAH rat models (i.g.). Notably, our study successfully demonstrated that the simultaneous regulation of Hsp110 and sGC dual targets was a novel and feasible strategy for PAH therapy, providing a promising lead compound for anti-PAH drug discovery.

Inhibition of Hsp110-STAT3 interaction in endothelial cells alleviates vascular remodeling in hypoxic pulmonary arterial Hypertension model.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a progressive and devastating disease characterized by pulmonary vascular remodeling which is associated with the malignant phenotypes of pulmonary vascular cells. Recently, the effects of heat shock protein 110 (Hsp110) in human arterial smooth muscle cells were reported. However, the underlying roles and mechanisms of Hsp110 in human pulmonary arterial endothelial cells (HPAECs) that was disordered firstly at the early stage of PAH remain unknown. METHODS: In this research, the expression of Hsp110 in PAH human patients and rat models was investigated, and the Hsp110 localization was determined both in vivo and in vitro. The roles and mechanism of elevated Hsp110 in excessive cell proliferation and migration of HPAECs were assessed respectively exposed to hypoxia. Small molecule inhibitors targeting Hsp110-STAT3 interaction were screened via fluorescence polarization, anti-aggregation and western blot assays. Moreover, the effects of compound 6 on HPAECs abnormal phenotypes in vitro and pulmonary vascular remodeling of hypoxia-indued PAH rats in vivo by interrupting Hsp110-STAT3 interaction were evaluated. RESULTS: Our studies demonstrated that Hsp110 expression was increased in the serum of patients with PAH, as well as in the lungs and pulmonary arteries of PAH rats, when compared to their respective healthy subjects. Moreover, Hsp110 levels were significantly elevated in HPAECs under hypoxia and mediated its aberrant phenotypes. Furthermore, boosted Hsp110-STAT3 interaction resulted in abnormal proliferation and migration via elevating p-STAT3 and c-Myc in HPAECs. Notably, we successfully identified compound 6 as potent Hsp110-STAT3 interaction inhibitor, which effectively inhibited HPAECs proliferation and migration, and significantly ameliorated right heart hypertrophy and vascular remodeling of rats with PAH. CONCLUSIONS: Our studies suggest that elevated Hsp110 plays a vital role in HPAECs and inhibition of the Hsp110-STAT3 interaction is a novel strategy for improving vascular remodeling. In addition, compound 6 could serve as a promising lead compound for developing first-in-class drugs against PAH.

Identification of selective homeodomain interacting protein kinase 2 inhibitors, a potential treatment for renal fibrosis.

Homeodomain interacting protein kinase 2 (HIPK2) has emerged as a promising target for the discovery of anti-renal fibrosis drugs. Herein, to develop specific pharmacologic inhibitors of HIPK2, we designed and synthesized a series of compounds containing benzimidazole and pyrimidine scaffolds via fragment-based drug design strategy. Kinase assay was applied to evaluate the inhibitory activity of target compounds against HIPKs enzyme. The molecular docking study suggest the contribution of tyrosine residues beside the active sites of HIPK1-3 to the selectivity of active compounds. Compound 15q displayed good selectivity and potent inhibitory activity against HIPK2 compared to other two subtype enzymes. 15q could downregulate phosphorylated p53, the direct substrate of HIPK2, and decrease the fibrosis-related downstream of HIPK2, such as p-Smad3 and α-SMA in NRK-49F cells. 15q showed no effect on the cell apoptosis in fibrotic or cancer cell lines, suggesting little cancer risk of 15q. Notably, 15q displayed encouraging in vivo anti-fibrotic effects in the unilateral ureteral obstruction mouse model, which could be used as a potential lead for structural optimization and candidate for the development of selective HIPK2 inhibitors.