Involvement of mitogen-activated protein kinase (MAPK)-activated protein kinase 2 (MK2) in endothelial dysfunction associated with pulmonary hypertension

Functionalized azirine based scaffolds as endothelin inhibitors for the selective anti-angiogenic activity

Anti-angiogenic therapy has long been used as an adjunct therapy for the resolution of tumor burden. The current findings describe the synthesis of novel marine-based azirine-containing compounds that exhibit anti-angiogenic mediated anti-tumor activity. Azirine-2-carboxylate inhibited HUVEC-mediated tubulogenesis without causing cell death in a dose-dependent manner. Ex-vivo CAM, in-vivo Matrigel implantation, and ear angiogenesis experiments have all shown that azirine-2-carboxylate effectively inhibits angiogenesis. Furthermore, azirine-2-carboxylate inhibits the migration of ECs without disrupting the preformed tubule network. Azirine-2-carboxylate had adequate intramuscular systemic exposure and inhibited tumor growth in a xenograft mouse model. DARTS analysis, competitive binding assay, and gene expression investigations revealed that azirine-2-carboxylate inhibits endothelin-1-mediated angiogenesis. Overall, the discovery of azirine-2-carboxylate demonstrated a potent inhibition of angiogenesis targeting ET1 and a possible application in anti-angiogenic therapy.

Methylglyoxal-Derived Nucleoside Adducts Drive Vascular Dysfunction in a RAGE-Dependent Manner

Diabetic kidney disease (DKD) is a leading cause of death in patients with diabetes. An early precursor to DKD is endothelial cell dysfunction (ECD), which often precedes and exacerbates vascular disease progression. We previously discovered that covalent adducts formed on DNA, RNA, and proteins by the reactive metabolic by-product methylglyoxal (MG) predict DKD risk in patients with type 1 diabetes up to 16 years pre-diagnosis. However, the mechanisms by which MG adducts contribute to vascular disease onset and progression remain unclear. Here, we report that the most predominant MG-induced nucleoside adducts, N2-(1-carboxyethyl)-deoxyguanosine (CEdG) and N2-(1-carboxyethyl)-guanosine (CEG), drive endothelial dysfunction. Following CEdG or CEG exposure, primary human umbilical vein endothelial cells (HUVECs) undergo endothelial dysfunction, resulting in enhanced monocyte adhesion, increased reactive oxygen species production, endothelial permeability, impaired endothelial homeostasis, and exhibit a dysfunctional transcriptomic signature. These effects were discovered to be mediated through the receptor for advanced glycation end products (RAGE), as an inhibitor for intracellular RAGE signaling diminished these dysfunctional phenotypes. Therefore, we found that not only are MG adducts biomarkers for DKD, but that they may also have a role as potential drivers of vascular disease onset and progression and a new therapeutic modality.

Inhibition of poly (ADP-ribose) Polymerase-1 (PARP-1) improves endothelial function in pulmonary hypertension

Endothelial dysfunction is critical in the pulmonary vasculature during pulmonary hypertension (PH). Moreover, in PH, increased inflammation and oxidative/nitrosative stress cause DNA damage, activating poly (ADP-ribose) polymerase-1 (PARP-1). Meloche et al. (2014) and our previous research have shown that inhibiting PARP-1 is protective in PH and associated RV hypertrophy. However, the role of PARP-1 in pulmonary arterial endothelial dysfunction has not been explored completely. Therefore, the current study aims to investigate the involvement of PARP-1 in endothelial dysfunction associated with PH. Hypoxia (1% O2) was used to induce a PH-like phenotype in human pulmonary artery endothelial cells (HPAECs), and PARP-1 inhibition was achieved via siRNA (60 nM). For the in vivo study, male Sprague Dawley rats were administered monocrotaline (MCT; 60 mg/kg, SC, once) to induce PH, and 1, 5-isoquinolinediol (ISO; 3 mg/kg) was administered daily intraperitoneally to inhibit PARP-1. PARP-1 inhibition decreased proliferation and inflammation, as well as improved mitochondrial dysfunction in hypoxic HPAECs. Furthermore, PARP-1 inhibition also promoted apoptosis by increasing DNA damage in hypoxic HPAECs. In addition, inhibition of PARP-1 reduced cell migration, VEGF expression, and tubule formation in hypoxic HPAECs. In in vivo studies, PARP-1 inhibition by ISO significantly decreased the RVP and RVH as well as improved endothelial function by increasing the pulmonary vascular reactivity and expression of p-eNOS in MCT-treated rats.

Novel p38 Mitogen-Activated Protein Kinase Inhibitor Reverses Hypoxia-Induced Pulmonary Arterial Hypertension in Rats

Mitogen-activated protein kinase (MAPK) signaling is strongly implicated in cardiovascular remodeling in pulmonary hypertension (PH) and right ventricle (RV) failure. The effects of a newly designed p38 inhibitor, LASSBio-1824, were investigated in experimentally induced PH. Male Wistar rats were exposed to hypoxia and SU5416 (SuHx), and normoxic rats were used as controls. Oral treatment was performed for 14 days with either vehicle or LASSBio-1824 (50 mg/kg). Pulmonary vascular resistance and RV structure and function were assessed by echocardiography and catheterization. Histological, immunohistochemical and Western blot analysis of lung and RV were performed to investigate cardiovascular remodeling and inflammation. Treatment with LASSBio-1824 normalized vascular resistance by attenuating vessel muscularization and endothelial dysfunction. In the heart, treatment decreased RV systolic pressure, hypertrophy and collagen content, improving cardiac function. Protein content of TNF-α, iNOS, phosphorylated p38 and caspase-3 were reduced both in lung vessels and RV tissues after treatment and a reduced activation of transcription factor c-fos was found in cardiomyocytes of treated SuHx rats. Therefore, LASSBio-1824 represents a potential candidate for remodeling-targeted treatment of PH.