Correction: Kinomic Profiling of Electromagnetic Navigational Bronchoscopy Specimens: A New Approach for Personalized Medicine

Targeting Jak-Stat Signaling in Experimental Pulmonary Hypertension

In pulmonary arterial hypertension (PAH), progressive structural remodeling accounts for the pulmonary vasculopathy including the obliteration of the lung vasculature that causes an increase in vascular resistance and mean blood pressure in the pulmonary arteries ultimately leading to right heart failure-mediated death. Deciphering the molecular details of aberrant signaling of pulmonary vascular cells in PAH is fundamental for the development of new therapeutic strategies. We aimed to identify kinases as new potential drug targets that are dysregulated in PAH by means of a peptide-based kinase activity assay. We performed a tyrosine kinase-dependent phosphorylation assay using 144 selected microarrayed substrate peptides. The differential signature of phosphopeptides was used to predict alterations in tyrosine kinase activities in human pulmonary arterial smooth muscle cells (HPASMCs) from patients with idiopathic PAH (IPAH) compared with healthy control cells. Thereby, we observed an overactivation and an increased expression of Jak2 (Janus kinase 2) in HPASMCs from patients with IPAH as compared with controls. In vitro, IL-6-induced proliferation and migration of HPASMCs from healthy individuals as well as from patients with IPAH were reduced in a dose-dependent manner by the U.S. Food and Drug Administration-approved Jak1 and Jak2 inhibitor ruxolitinib. In vivo, ruxolitinib therapy in two experimental models of pulmonary arterial hypertension dose-dependently attenuated the elevation in pulmonary arterial pressure, partially reduced right ventricular hypertrophy, and almost completely restored cardiac index without signs of adverse events on cardiac function. Therefore, we propose that ruxolitinib may present a novel therapeutic option for patients with PAH by reducing pulmonary vascular remodeling through effectively blocking Jak2-Stat3 (signal transducer of activators of transcription)-mediated signaling pathways.

Metformin induces lipogenic differentiation in myofibroblasts to reverse lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal disease in which the intricate alveolar network of the lung is progressively replaced by fibrotic scars. Myofibroblasts are the effector cells that excessively deposit extracellular matrix proteins thus compromising lung structure and function. Emerging literature suggests a correlation between fibrosis and metabolic alterations in IPF. In this study, we show that the first-line antidiabetic drug metformin exerts potent antifibrotic effects in the lung by modulating metabolic pathways, inhibiting TGFβ1 action, suppressing collagen formation, activating PPARγ signaling and inducing lipogenic differentiation in lung fibroblasts derived from IPF patients. Using genetic lineage tracing in a murine model of lung fibrosis, we show that metformin alters the fate of myofibroblasts and accelerates fibrosis resolution by inducing myofibroblast-to-lipofibroblast transdifferentiation. Detailed pathway analysis revealed a two-arm mechanism by which metformin accelerates fibrosis resolution. Our data report an antifibrotic role for metformin in the lung, thus warranting further therapeutic evaluation.

Idiopathic pulmonary fibrosis is associated with myofibroblast activation in the lungs and metabolic alterations. Here, the authors show that the antidiabetic drug metformin has antifibrotic effects in human-derived samples and mouse models, by modulating a number of metabolic pathways to induce lipogenic transdifferentiation of myofibroblasts.