SHP-1 mediates cigarette smoke extract-induced epithelial-mesenchymal transformation and inflammation in 16HBE cells.

Src-homology region 2 domain-containing phosphatase 1 (SHP-1) is considered an anti-inflammatory factor, but its role in chronic obstructive pulmonary disease (COPD) remains unknown. Herein, overexpression of SHP-1 was utilized to explore the functions of SHP-1 in COPD models established by stimulating 16HBE cells with cigarette smoke extracts (CSE) in vitro. SHP-1 was downregulated in both COPD patients and CES-treated 16HBE cells. SHP-1 overexpression reinforced cell viability and significantly prevented CSE-induced cell apoptosis in 16HBE cells. Furthermore, SHP-1 overexpression greatly reversed the CSE-induced migration, epithelial-mesenchymal transition (EMT), and pro-inflammatory factor production in 16HBE cells. In addition, CSE activated the P65 and PI3K/AKT pathways in 16HBE cells, which was also reversed by SHP-1 overexpression. Our findings indicated that SHP-1 alleviated CSE-induced EMT and inflammation in 16HBE cells, suggesting that SHP-1 regulated the development of COPD, and these functions may be linked to the inhibition of the PI3K/AKT pathway.

Pectolinarigenin ameliorated airway inflammation and airway remodeling to exhibit antitussive effect.

Cough is a common symptom of several respiratory diseases. However, frequent coughing from acute to chronic often causes great pain to patients. It may turn into cough variant asthma, which seriously affects people's quality of life. For cough treatment, it is dominated by over-the-counter antitussive drugs, such as asmeton, but most currently available antitussive drugs have serious side effects. Thus, there is a great need for the development of new drugs with potent cough suppressant. BALB/c mice were used to construct mice model with cough to investigate the pharmacological effects of pectolinarigenin (PEC). Hematoxylin-eosin and Masson staining were used to assess lung injury and airway remodeling, and ELISA was used to assess the level of inflammatory factor release. In addition, inflammatory cell counts were measured to assess airway inflammation. Airway hyperresponsiveness assay was used to assess respiratory resistance in mice. Finally, we used Western blotting to explore the potential mechanisms of PEC. We found that PEC could alleviate lung tissue injury and reduce the release of inflammatory factors, inhibit of cough frequency and airway wall collagen deposition in mice model with cough. Meanwhile, PEC inhibited the Ras/ERK/c-Fos pathway to exhibit antitussive effect. Therefore, PEC may be a potential drug for cough suppression.

Molecular design and systematic optimization of a halogen-bonding system between the asthma interleukin-5 receptor and its cyclic peptide ligand.

Human interleukin-5 (IL-5) functions as an important pro-inflammatory factor by binding to its specific receptor, IL-5Rα, which has been implicated in the pathogenesis of asthma. Previously, a disulfide-bonded cyclic peptide AF17121 obtained from random library screening and sequence variation was found to competitively disrupt the cognate IL-5Rα/IL-5 interaction with moderate potency. In this study, the crystal complex of IL-5Rα with AF17121 was investigated at structural and energetic levels. It is revealed that the side-chain indole moiety of the AF17121 Trp5 residue is a potential site for a stem putative halogen bond (X-bond) with IL-5Rα, which is just located within the key 3 EXXR6 motif region recognized specifically by IL-5Rα. We systematically examined four halogen substitution types at five positions of the indole moiety; QM/MM calculations theoretically unraveled that only halogenations at 5 and 6 positions can form effective X-bonds with the side-chain hydroxyl oxygen of the IL-5Rα Thr21 residue and the backbone carbonyl oxygen of Ala66 residue, respectively. Binding assays observed that I-substitution at the 5 position and Br-substitution at the 6 position can result in two potent halogenated peptides, [5I]AF17121 and [6Br]AF17121, which are improved by 1.6-fold and 3.5-fold relative to the native AF17121, respectively. 5I/6Br-double substitution, resulting in [5I/6Br]AF17121, can further enhance the peptide affinity by 7.5-fold. Structural analysis revealed that the X-bond stemming from 6Br-substitution is also involved in an orthogonal interaction system with a H-bond; they share a common backbone carbonyl oxygen acceptor of IL-5Rα Ala66 residue and exhibit a significant synergistic effect between them.

Coupled folding-upon-binding of human tumor suppressor MIG6 to lung cancer EGFR kinase domain and molecular trimming/stapling of MIG6-derived ß-hairpins to target the coupling event.

Human epidermal growth factor receptor (EGFR) is involved in strong association with malignant proliferation, which has been shown to play a central role in the development and progression of non-small cell lung cancer and other solid tumors. The tumor-suppressor protein MIG6 is a negative regulator of EGFR kinase activity by binding at the activation interface of asymmetric dimer of EGFR kinase domain to disrupt EGFR dimerization and then inactivate the kinase. The protein adopts two discrete fragments 1 and 2 to directly interact with EGFR. It is revealed that the MIG6 fragment 2 is intrinsically disordered in free unbound state, but would fold into a well-structured ß-hairpin when binding to EGFR, thus characterized by a so-called coupled folding-upon-binding process, which can be regarded as a compromise between favorable direct readout and unfavorable indirect readout. Here, a 23-mer F2P peptide was derived from MIG6 fragment 2, trimmed into a 17-mer tF2P peptide that contains the binding hotspot region of the fragment 2, and then constrained with an ordered hairpin conformation in free unbound state by disulfide stapling, finally resulting in a rationally stapled/trimmed stF2P peptide that largely minimizes the unfavorable indirect readout effect upon its binding to EGFR kinase domain, with affinity improved considerably upon the trimming and stapling/trimming. These rationally designed ß-hairpin peptides may be further exploited as potent anti-lung cancer agents to target the activation event of EGFR dimerization.