Discovery of a novel DDRs kinase inhibitor XBLJ-13 for the treatment of idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic fatal lung disease characterized by destruction of lung parenchyma and deposition of extracellular matrix in interstitial and alveolar spaces. But known drugs for IPF are far from meeting clinical demands, validation of drug targets against pulmonary fibrosis is in urgent demand. Tyrosine kinase receptor DDRs has been considered as a potential therapeutic target for pulmonary fibrosis due to its pathological collagen binding property and the roles in regulating extracellular matrix remodeling. In this study we designed and synthesized a new indazole derivative XBLJ-13, and identified XBLJ-13 as a highly specific and potent DDRs inhibitor with anti-inflammation and anti-fibrosis activities. We first demonstrated that DDR1/2 was highly expressed in the lung tissues of IPF patients. Then we showed that XBLJ-13 potently inhibited DDR1 and DDR2 kinases with IC50 values of 17.18 nM and 15.13 nM, respectively. Among a panel of 34 kinases tested, XBLJ-13 displayed relatively high selectivity for DDRs with minimal inhibitory effect on PDGFR family and FGFR1, as well as Abl kinase that had high homology with DDRs. Extensive profiling of XBLJ-13 revealed that the new inhibitor had much lower toxicity than nintedanib and better pharmacokinetic properties in mice. Furthermore, pharmacodynamic evaluation conducted in bleomycin-induced pulmonary fibrosis mice showed that administration of XBLJ-13 (30, 60, 90 mg·kg-1·d-1, i.g.) for 12 days significantly and dose-dependently ameliorated lung inflammation and fibrosis. Together, this study confirms that DDRs kinase is a potential target for PF, Particularly, compound XBLJ-13 is a highly potent and specific DDRs inhibitor, along with good pharmacokinetics profiles, and preferable in vivo efficacy, suggesting that it is a potential candidate for the treatment of PF.

Roxithromycin attenuates bleomycin-induced pulmonary fibrosis by targeting senescent cells.

Idiopathic pulmonary fibrosis (IPF) is an aging-associated disease with a poor prognosis. Emerging evidence has revealed that targeting senescent cells may be a potential treatment for IPF. In this study, we aimed to explore whether roxithromycin (RXM) can improve lung fibrosis by targeting senescent cells. First, we confirmed the ability of RXM to selectively kill senescent cells by inducing apoptosis and inhibiting the expression of senescence-associated secretory phenotype (SASP) factors, suggesting the potential role of RXM as a "senolytic" and "senomorphic" drug. Next, we observed that TGF-ß- and senescent cell-induced lung fibroblast activation was inhibited by RXM treatment, which prompted us to further investigate its effect in vivo. In a mouse model of bleomycin (BLM)-induced pulmonary fibrosis, RXM was shown to attenuate lung injury, inflammation, and fibrosis. Furthermore, the senescent phenotype of lung tissues induced by BLM was significantly diminished after RXM administration, indicating the potential of RXM as an antifibrotic and antisenescent agent. Interestingly, NADPH oxidase 4 (NOX4), implicated in lung fibrosis and cell senescence, was shown to be inhibited by RXM treatments. The antifibroblast activation and antisenescent effects of RXM were abolished in NOX4 knockdown cells, demonstrating that RXM may ameliorate BLM-induced pulmonary fibrosis by targeting senescent cells mediated by the NOX4 pathway. Collectively, these data demonstrated that RXM may be a potential clinical agent for IPF and further supported the notion that targeting cellular senescence is a promising treatment for progressive age-related disease.

Microenvironment-Responsive Small-Molecule Probe for Pulmonary Fibrosis Detection.

Pulmonary fibrosis (PF) is a fatal disease with increasing prevalence. Nonradioactive and noninvasive diagnosis of PF at an early stage can improve the prognosis but represents a daunting challenge. Up-regulation of nitric oxide (NO) is a typical microenvironmental feature of PF. Here, we report a small-molecule probe, PNO1, that can fluorogenically sense this microenvironmental feature for PF diagnosis. We demonstrate that PNO1 fluorescence is 6-fold higher in PF-diseased mice lungs than in normal-control groups. In addition to this in vivo result, PNO1 can also be applied in vitro to detect PF-diseased cells and ex vivo to detect PF-diseased tissues from clinical patients. These results highlight PNO1 as a complement to the traditional immunostaining-based methods for PF detection to facilitate quick screening for anti-PF drug candidates.