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.

The association of arterial stiffness with estimated excretion levels of urinary sodium and potassium and their ratio in Chinese adults.

Arterial stiffness is an independent cardiovascular risk factor. However, the association between sodium/potassium intake and arterial stiffness in the Chinese population is unclear. Therefore, we performed a large, community-based cross-sectional study to reach a more definitive conclusion. The study was conducted at the Third Xiangya Hospital in Changsha between August 2017 and September 2019. Urinary sodium, potassium, and creatinine levels were tested from spot urine samples during physical examinations of each recruited participant. The 24-hour estimated urinary sodium excretion (eUNaE) and estimated urinary potassium excretion (eUKE) levels were calculated using the Kawasaki formula (used as a surrogate for intake). The brachial-ankle pulse wave velocity (baPWV) and ankle brachial index (ABI) were measured using an automatic waveform analyzer. In 22,557 subjects with an average age of 49.3 ± 10.3 years, the relationships of the ABI and baPWV with the levels of eUNaE, eUKE and the ratio of sodium to potassium (Na/K ratio) were analyzed. A significant negative relationship was found between the eUKE and baPWV levels (ß = 2.41, p < 0.01), whereas the Na/K ratio was positively associated with baPWV (ß = 2.46, p < 0.01), especially in the overweight and hypertensive populations (both pinteraction = 0.04). The association of eUNaE quartiles with baPWV presented a J-shaped curve after adjusting for confounders. In addition, a positive association was observed between the Na/K ratio and the ABI (ß = 0.002, p < 0.01). In this study, high potassium and/or low sodium intake was further confirmed to be related to vascular stiffness in Chinese individuals.

An emerging strategy for targeted therapy of pulmonary arterial hypertension: Vasodilation plus vascular remodeling inhibition.

Pulmonary arterial hypertension (PAH) is a rapidly progressing disease with limited therapeutic options. Studies have elucidated the multifactorial pathological characteristics of PAH, indicating the complexity and difficulty of PAH treatment. Currently available treatments focus primarily on vasodilation rather than on vascular remodeling, although several drugs have been developed for the latter. This paradigm for management leads to PAH remaining an incurable disease; thus, there is an urgent need to explore new strategies for coping with this devastating disease. In this review, we discuss current strategies and options for PAH therapy and emerging novel therapeutic approaches in PAH treatment. This viewpoint suggests a shift in PAH treatment strategy from mono-activity to dual effects on vasoconstriction and vascular remodeling.

TPN171H alleviates pulmonary hypertension via inhibiting inflammation in hypoxia and monocrotaline-induced rats.

Pulmonary hypertension (PH) is a progressive and life-threatening disease with poor prognosis despite many advances in medical therapy over the past 20 years. Novel therapies which target on the underlying pathology of PH are still urgent to be met. TPN171H is a recently found new compound that exhibits potent pharmacological effects in PH via inhibiting phosphodiesterase type 5 (PDE-5). However, as one icariin derivative, the anti-inflammatory effects of TPN171H for treating PH are not clear. The present study was designed to investigate the therapeutical effect of TPN171H against inflammation in PH and reveal the underlying mechanism. Hypoxia and monocrotaline (MCT)-induced PH rat models were established, which were treated by oral administration of TPN171H (5, 25 mg/kg/d) or sildenafil (25 mg/kg/d). The right ventricle systolic pressure (RVSP), right ventricle hypertrophy index (RVHI) and vascular remodeling were measured. The results suggested that TPN171H significantly reduced RVSP and RVHI, and reversed pulmonary vascular remodeling in rats with both models. Furthermore, in in vivo and in vitro research, our data suggested that TPN171H remarkably suppressed cathepsin B-mediated NLRP3 inflammasome activation, which may contribute to its therapeutical function for PH.

Novel Pyrazolo[3,4-b] Pyridine Derivative (HLQ2g) Attenuates Hypoxic Pulmonary Hypertension via Restoring cGKI Expression and BMP Signaling Pathway.

Pulmonary hypertension (PH) is an extremely serious cardiopulmonary disease, finally leading to progressive right ventricular failure and death. Our previous studies have nominated HLQ2g, a pyrazolo[3,4-b] pyridine derivative stimulating soluble guanylate cyclase (sGC), as a new candidate for the treatment of PH, but the specific mechanism is still not clear. The PH model induced by hypoxia was established in rats. Right ventricular systolic pressure (RVSP) was assessed by jugular vein catheterization. RV weight was the index to evaluate RV hypertrophy. The protein levels of cGMP-dependent protein kinase type I (cGKI), bone morphogenetic protein receptor 2 (BMPR2), phosphorylated Smad1/5/8 (p-Smad1/5/8), and inhibitor of differention 1 (Id1) in pulmonary artery and human pulmonary artery smooth muscle cells (HPASMCs) were determined by western blotting. Cell proliferation and migration were evaluated. In the whole experiment, the first clinically available sGC stimulator Riociguat was used as the reference. In hypoxic PH rat model, elevated RVSP and RV hypertrophy were significantly reduced by HLQ2g treatment. Both Riociguat and HLQ2g attenuated vascular remodeling accompanied with up-regulated cGKI expression and BMP signaling pathway, which was characterized by elevated expression of BMPR2, p-Smad1/5/8, and Id1 in HPH rats. In addition, HLQ2g inhibited proliferation and migration of HPASMCs induced by hypoxia and platelet-derived growth factor (PDGF), restored BMPR2 signaling, which was recalled by Rp-8-Br-PET-cGMPS, the inhibitor of cGKI. In summary, the novel pyrazolo[3,4-b] pyridine derivative HLQ2g can alleviate HPH progression by up-regulating cGKI protein and BMP signaling pathway.