Search

Metabolic reprogramming of the myofibroblast plays a fundamental role in the pathogenesis of fibrosing interstitial lung diseases. Here, we characterized the in vitro and in vivo metabolic and anti-fibrotic effects of IM156, an oxidative phosphorylation (OXPHOS) modulator that acts by inhibiting Protein Complex 1 (PC1). In vitro, IM156 inhibited TGFβ-dependent increases in mitochondrial oxygen consumption rate and expression of myofibroblast markers in human pulmonary fibroblasts without altering cell viability or adding to TGF-β induced increases in the extracellular acidification rate (ECAR). IM156 significantly increased cellular AMPK phosphorylation and was 60-fold more potent than metformin. In vivo, chronic oral administration of IM156 was highly distributed to major peripheral organs (i.e. lung, liver, kidney, heart) and had significant dose-related effects on the plasma metabolome consistent with OXPHOS modulation and AMPK activation. IM156 increased glycolysis, lipolysis, β-oxidation and amino acids, and decreased free fatty acids, TCA cycle activity and protein synthesis. In the murine bleomycin model of pulmonary fibrosis, daily oral administration of IM156 administered 7 days after lung injury, attenuated body/lung weight changes, and reduced lung fibrosis and inflammatory cell infiltration. The plasma exposures of IM156 were comparable to well-tolerated doses in human studies. In conclusion, the metabolic and anti-fibrotic effects of IM156 suggest that OXPHOS modulation can attenuate myofibroblast metabolic reprogramming and support testing IM156 as a therapy for IPF and other fibrotic diseases. Significance Statement Fibrosing Interstitial Lung Diseases (FILD) have a poor prognosis and current anti-fibrotic treatments have significant limitations. This study demonstrates that attenuation of fibrogenic metabolic remodeling, by modulation of OXPHOS with IM156, prevents the myofibroblast phenotype/collagen deposition and is a potentially effective and translational anti-fibrotic strategy.

The evidence is compelling for a role of inflammation in cardiovascular diseases; however, the chronic use of anti-inflammatory drugs for these indications has been disappointing. The recent study compares the effects of two anti-inflammatory agents [cyclooxygenase 2 (COX2) and p38 inhibitors] in a model of cardiovascular disease. The vascular, renal, and cardiac effects of 4-(4-methylsulfonylphenyl)-3-phenyl-5H-furan-2-one (rofecoxib; a COX2 inhibitor) and 6-{5-[(cyclopropylamino)carbonyl]-3-fluoro-2-methylphenyl}-N-(2,2-dimethylpropyl)-3-pyridinecarboxamide [GSK-AHAB, a selective p38 mitogen-activated protein kinase (MAPK) inhibitor], were examined in the spontaneously hypertensive stroke-prone rat (SHR-SP). In SHR-SPs receiving a salt-fat diet (SFD), chronic treatment with GSK-AHAB significantly and dose-dependently improved survival, endothelial-dependent and -independent vascular relaxation, and indices of renal function, and it attenuated dyslipidemia, hypertension, cardiac remodeling, plasma renin activity (PRA), aldosterone, and interleukin-1beta (IL-1beta). In contrast, chronic treatment with a COX2-selective dose of rofecoxib exaggerated the harmful effects of the SFD, i.e., increasing vascular and renal dysfunction, dyslipidemia, hypertension, cardiac hypertrophy, PRA, aldosterone, and IL-1beta. The protective effects of a p38 MAPK inhibitor are clearly distinct from the deleterious effects of a selective COX2 inhibitor in the SHR-SP and suggest that anti-inflammatory agents can have differential effects in cardiovascular disease. The results also suggest a method for evaluating long-term cardiovascular efficacy and safety.

Long and short QT syndromes associated with loss and gain of human ether-a-go-go-related gene (hERG) channel activity, respectively, can cause life-threatening arrhythmias. As such, modulation of hERG channel activity is an important consideration in the development of all new therapeutic agents. In the present study, we investigated the mechanisms of action of 2-[2-(3,4-dichloro-phenyl)-2,3-dihydro-1H-isoindol-5-ylamino]-nicotinic acid (PD-307243), a known hERG channel activator, on hERG channels stably expressed in Chinese hamster ovary (CHO) cells using the patch-clamp technique. In the whole-cell recordings, the extracellular application of PD-307243 concentration-dependently increased the hERG current and markedly slowed hERG channel deactivation and inactivation. PD-307243 had no effect on the selectivity filter of hERG channels. The activity of PD-307243 was use-dependent. PD-307243 (3 and 10 muM) induced instantaneous hERG current with little decay at membrane potentials from -120 to -40 mV. At more positive voltages, PD-307243 induced an I(to)-like upstroke of hERG current. The actions of PD-307243 on the rapid component of delayed rectifier K(+) current (I(Kr)) in rabbit ventricular myocytes were similar to those observed in hERG channel-transfected CHO cells. Inside-out patch experiments revealed that PD-307243 increased hERG tail currents by 2.1 +/- 0.6 (n = 7) and 3.4 +/- 0.3-fold (n = 4) at 3 and 10 muM, respectively, by slowing the channel deactivation but had no effect on channel activation. During a voltage-clamp protocol using a prerecorded cardiac action potential, 3 muM PD-307243 increased the total potassium ions passed through hERG channels by 8.8 +/- 1.0-fold (n = 5). Docking studies suggest that PD-307243 interacts with residues in the S5-P region of the channel.

Increased Rho kinase (ROCK) activity contributes to smooth muscle contraction and regulates blood pressure homeostasis. We hypothesized that potent and selective ROCK inhibitors with novel structural motifs would help elucidate the functional role of ROCK and further explore the therapeutic potential of ROCK inhibition for hypertension. In this article, we characterized two aminofurazan-based inhibitors, GSK269962A [N-(3-{[2-(4-amino-1,2,5-oxadiazol-3-yl)-1-ethyl-1H-imidazo[4, 5-c]pyridin-6-yl]oxy}phenyl)-4-{[2-(4-morpholinyl)ethyl]-oxy}benzamide] and SB-7720770-B [4-(7-{[(3S)-3-amino-1-pyrrolidinyl]carbonyl}-1-ethyl-1H-imidazo[4,5-c]pyridin-2-yl)-1,2,5-oxadiazol-3-amine], as members of a novel class of compounds that potently inhibit ROCK enzymatic activity. GSK269962A and SB-772077-B have IC50 values of 1.6 and 5.6 nM toward recombinant human ROCK1, respectively. GSK269962A also exhibited more than 30-fold selectivity against a panel of serine/threonine kinases. In lipopolysaccharide-stimulated monocytes, these inhibitors blocked the generation of inflammatory cytokines, such as interleukin-6 and tumor necrosis factor-alpha. Furthermore, both SB-772077-B and GSK269962A induced vasorelaxation in preconstricted rat aorta with an IC50 of 39 and 35 nM, respectively. Oral administration of either GSK269962A or SB-772077-B produced a profound dose-dependent reduction of systemic blood pressure in spontaneously hypertensive rats. At doses of 1, 3, and 30 mg/kg, both compounds induced a reduction in blood pressure of approximately 10, 20, and 50 mm Hg. In addition, administration of SB-772077-B also dramatically lowered blood pressure in DOCA salt-induced hypertensive rats. SB-772077-B and GSK269962A represent a novel class of ROCK inhibitors that have profound effects in the vasculature and may enable us to further evaluate the potential beneficial effects of ROCK inhibition in animal models of cardiovascular as well as other chronic diseases.

Recent evidence suggests p38 mitogen-activated protein kinase (MAPK) signal transduction plays an important role in the pathogenesis of progressive renal disease. Using dynamic contrast enhanced magnetic resonance imaging (MRI), we evaluated chronic treatment with a p38 MAPK inhibitor, trans-1-(4-hydroxycyclohexyl)-4-(4-fluorophenyl-methoxypyridimidin-4-yl)imidazole (SB-239063), on renal function in a hypertension model of progressing renal dysfunction. Spontaneously hypertensive-stroke prone rats were placed on a high salt/fat diet (SFD) or maintained on normal chow diet (ND). SFD animals with albuminuria at 4 to 8 weeks (or =10 mg/day inclusion criteria), were randomized into p38 MAPK inhibitor treatment (SB-239063, 1200 ppm in diet) or vehicle groups. The progression of blood pressure and albuminuria during the treatment period (approximately 6 weeks) was decreased by 12 and 60%, respectively, in the SFD + SB-239063 versus SFD control group. Renal perfusion and filtration were assessed by in vivo MRI at the end of the study. Relative cortical perfusion was increased in the SFD + SB-239063 group compared with the SFD control group as reflected by a 29% decrease in time to peak of contrast agent in the cortex. Additionally, the regional renal glomerular filtration rate index (Kcl) was increased by 39% in the SFD + SB-239063 versus SFD control group and was normalized to the ND control group. Greater functional heterogeneity was observed in the SFD control versus SFD + SB-239063 or ND control group. All alterations of renal function were supported by histopathological findings. In conclusion, chronic treatment with a p38 MAPK inhibitor, SB-239063, attenuates functional and structural renal degeneration in a hypertensive model of established renal dysfunction.

Numerous mediators, believed to play a role in endothelial dysfunction (e.g., neurohormones, cytokines, hypoxia, and stretch), have been shown to activate p38 mitogen-activated protein kinase (MAPK) in a variety of cell types. The purpose of the present study was to examine the regulation of p38 MAPK in endothelium and its role in endothelial dysfunction and salt sensitivity. In cultured human umbilical vein endothelial cells (HUVECs), tumor necrosis factor-alpha and lipopolysaccharide increased phosphorylation of p38 MAPK (P-p38 MAPK) and increased ICAM-1 expression. Preincubation with highly selective p38 MAPK inhibitors, 1-(1,3-dihydroxyprop-2-yl)-4-(4-fluorophenyl)-5-[2-phenoxypyrimidin-4-yl] imidazole (SB-239063AN) or SB-239063, dose dependently reduced intercellular adhesion molecule-1 expression in HUVECs. In spontaneously hypertensive-stroke prone rats (SHR-SP), P-p38 MAPK was localized by immunohistochemistry to the aortic endothelium and adventitia but was undetectable in aortae from normotensive rats. Introduction of a salt/fat diet (SFD) to the SHR-SP strain induced endothelial dysfunction (ex vivo vascular reactivity analysis), albuminuria, and an increase in blood pressure within 4 weeks. Chronic dietary dosing (approx. 100 mg/kg/day) with SB-239063AN inhibited the SFD diet-induced hypertension. In addition, delayed treatment also significantly improved survival and restored nitric oxide-mediated endothelium-dependent relaxation in SFD-SHR-SPs with established endothelial dysfunction. These results suggest an important role for p38 MAPK in endothelial inflammation and dysfunction as well as providing the first evidence for p38 MAPK-dependent hypertension.