Computational Study on Novel Natural Inhibitors Targeting Janus Kinase 3

Objective: The aim of this study is to screen and identify novel leading compounds 5 which can inhibit protein Janus Kinase 3 (JAK3) from a drug library (ZINC database) 6 to provide precise target therapy for lung cancer. 7Methods: A set of computation-aided structural biology methods and chemical virtual 8 screening techniques were carried out to screen novel inhibitor compounds. Libdock 9 scores for potential inhibitors of JAK3 were calculated using fast docking method-10 virtual screening. Next, ADMET properties (absorption, distribution, metabolism, 11 excretion, and toxicity) were conducted to predict their pharmacological characteristics. 12 The binding affinity as well as the interactions between the candidate compounds and 13 JAK3 were calculated and visualized by precise molecular docking algorithm. 14 Ultimately, molecular dynamics simulation (MD) was performed to estimate the 15 stability of the ligand-JAK3 complex under natural environment. 16Results: After screening, two novel natural compounds, ZINC000014952116 and 17 ZINC00000393864, were finally selected as leading compounds from the ZINC15 18 database, which possessed less Ames mutagenicity, rodent carcinogenicity and 19 developmental toxicity potential than other candidate compounds. Additionally, they 20 didn’t inhibit the activity of CYP2D6. Molecular dynamics simulation analysis showed 21 that ZINC000014952116 and ZINC00000393864 could interact with JAK3 steadily, 22 and their ligand-JAK3 complexes could keep stable under natural situation, and act as 23 regulatory role to JAK3. 24Conclusion: This study analyzed that ZINC000014952116 and ZINC00000393864 25 were ideal natural inhibitors targeting JAK3 from the ZINC15 database, which could 26 also provide more options and resources for other cancer chemotherapy.

Janus Kinase 3 Deficiency Promotes Vascular Reendothelialization

Objective: The objective of this study is to determine the role of JAK3 (Janus kinase 3) in reendothelialization after vascular injury. Methods and Results: By using mouse carotid artery wire injury and rat balloon injury model, we found that JAK3 regulates reendothelialization and endothelial cell proliferation after vascular injury. JAK3 and phospho-JAK3 levels were increased in neointimal smooth muscle cells in response to vascular injury in mice. JAK3 deficiency dramatically attenuated the injury-induced intimal hyperplasia in carotid arteries of both male and female mice. Importantly, JAK3 deficiency caused an increased rate of reendothelialization following mechanical injury. Likewise, knockdown of JAK3 in medial smooth muscle cells elicited an accelerated reendothelialization with reduced intimal hyperplasia following balloon injury in rat carotid arteries. Interestingly, knockdown of JAK3 restored the expression of smooth muscle cell contractile protein smooth muscle α-actin in injury-induced intimal smooth muscle cells while increased the proliferating endothelial cells in the intima area. Conclusions: Our results demonstrate a novel role of JAK3 in the regeneration of endothelium after vascular injury, which may provide a new strategy to enhance reendothelialization while suppressing neointimal formation for effective vascular repair from injury.

Molecular modeling on the identification of potential Janus Kinase 3 (JAK3) inhibitor based on the Indonesian Medicinal Plant Database

The Janus tyrosine kinases (JAKs) have shown great promise as therapeutic protein targets in the treatment of cancer and inflammation diseases. This study used pharmacophore modeling to identify potential inhibitors of Janus kinase 3 (JAK3). A pharmacophore model was developed based on a known JAK3 inhibitor (1NX) and was employed to search for potential JAK3 inhibitors against Indonesian herbal compounds. Among 28 hit molecules that were identified and subjected to a molecular docking protocol against JAK3, the three compounds that had the highest affinities toward JAK3 were camelliaside B, 3-O-galloylepicatechin-(4beta-6)-epicatechin-3-O-gallate, and mesuaferrone B. These were then each subjected to a 50-ns molecular dynamics (MD) simulation. Analysis of RMSD and RMSF values indicated that the three compounds reached stability during the MD simulation. Interestingly, all three compounds had lower binding energies than 1NX against JAK3, as predicted by the MM-PBSA binding energy calculation.

JANEX-1 improves acute pulmonary embolism through VEGF and FAK in pulmonary artery smooth muscle cells

Although clinical treatment has significant progress, acute pulmonary embolism is still a common disease with high morbidity and mortality. Janus Kinase 3, a member of JAK family, has been demonstrated to promote smooth muscle cell proliferation through STAT3. In this work, we explored the effect of JANEX-1 (a specific Janus Kinase 3 inhibitor) on platelet-derived growth factor (PDGF)-induced proliferation-related molecules in pulmonary artery smooth muscle cells (PVSMCs) in vitro and assessed the therapeutic potential of Janus Kinase 3 for vascular remodeling in acute pulmonary embolism mice. The results revealed that Janus Kinase 3 was overexpressed and active in PDGF-induced PVSMCs and acute pulmonary embolism mice, compared to a low expression in normal conditions. JANEX-1, blocking Janus Kinase 3 expression or activity, reduced Janus Kinase 3/STAT3 signaling pathway, VEGF expression, FAK activation, and PDGF-induced proliferation of PVSMCs, while overexpression of VEGF or FAK induced PVSMCs proliferation and resisted the negative effects of JANEX-1. Moreover, JANEX-1 improved right ventricular systolic pressure, survival and lung damage in acute pulmonary embolism-mice, and inhibited the thrombus-induced intimal hyperplasia and the expression of α-SMA, VEGF, and FAK activation under neointimal smooth muscle cells of acute pulmonary embolism mice. In conclusion, the data suggest that JANEX-1 exerts protective effects by inhibiting PVSMCs proliferation and vascular remodeling post-acute pulmonary embolism, in part through Janus Kinase 3/STAT3 signaling pathway-mediated VEGF expression and FAK activation. The data are helpful to elucidate the pharmacological mechanism and potential therapeutic effect of JANEX-1 in APE. Impact statement Accumulating evidence suggests that vascular remodeling due to immoderate proliferation and migration of SMCs is a common process occurring in APE. In this work, we tried to find a breakthrough in the pathological mechanism to alleviate the prognosis of APE by improving SMCs proliferation and explored the effect of JANEX-1 on PDGF-induced proliferation-related molecules in PVSMCs and assessed the therapeutic potential of JAK3 for vascular remodeling in APE mice. We demonstrated that JANEX-1, blocking JAK3 expression or activity, reduced JAK3/STAT3 signaling pathway, VEGF expression and FAK activation, and PDGF-induced proliferation of PVSMCs. Moreover, JANEX-1 inhibited the thrombus-induced intimal hyperplasia and the expression of VEGF and FAK activation in neointimal SMCs of APE mice. The data are helpful to elucidate the pharmacological mechanism and potential therapeutic effect of JANEX-1 in APE.

Pharmacophore modeling and 3D-QSAR studies of 2,4-disubstituted pyrimidine derivatives as Janus kinase 3 inhibitors

A robust pharmacophore model was developed and the structure-activity relationship was analyzed using 71 pyrimidine derivatives reported for covalent Janus Kinase 3 (JAK3) inhibition. Pharmacophore modeling developed a five featured pharmacophore: one H-bond acceptor, two H-bond donors, one hydrophobic, and one aromatic ring features. The atom-based three-dimensional QSAR models with statistical significance were generated using the training set of 52 compounds. The excellent predictive correlation coefficients were obtained for 3D models determined using a test set of 19 molecules. The generated QSAR model implies that the hydrophobic character is important for the JAK3 inhibitory activity of these compounds. Additionally, electron-withdrawing and hydrogen bond donor groups at specific positions positively contribute to the JAK3 inhibition potency. These results provided essential three-dimensional structural requirements and the crucial binding features of 2,4-disubstituted pyrimidine derivatives, which may direct for the design and discovery of novel potent JAK3 inhibitors.