Establishment of rapid risk assessment model for cigarette smoke extract exposure in chronic obstructive pulmonary disease

Naringenin attenuated airway cilia structural and functional injury induced by cigarette smoke extract via IL-17 and cAMP pathways

BACKGROUND

Cigarette smoke impairs mucociliary clearance via mechanisms such as inflammatory response and oxidative injury, which in turn induces various respiratory diseases. Naringenin, a naturally occurring flavonoid in grapes and grapefruit, has exhibited pharmacological properties such as anti-inflammatory, expectorant, and antioxidant properties. However, it is still unclear whether naringenin protects airway cilia from injury caused by cigarette smoke.

PURPOSE

This study aimed to investigate the effect of naringenin on cigarette smoke extract (CSE)-induced structural and functional abnormalities in airway cilia and highlight the potential regulatory mechanism.

METHODS

Initially, network pharmacology was used to predict the mechanism of action of naringenin in ciliary disease. Next, HE staining, immunofluorescence, TEM, qRT-PCR, western blot, and ELISA were performed to assess the effects of naringenin on airway cilia in tracheal rings and air-liquid interface (ALI) cultures of Sprague Dawley rats after co-exposure to CSE (10% or 20%) and naringenin (0, 25, 50, 100 μM) for 24 h. Finally, transcriptomics and molecular biotechnology methods were conducted to elucidate the mechanism by which naringenin protected cilia from CSE-induced damage in ALI cultures.

RESULTS

The targets of ciliary diseases regulated by naringenin were significantly enriched in inflammation and oxidative stress pathways. Also, the CSE decreased the number of cilia in the tracheal rings and ALI cultures and reduced the ciliary beat frequency (CBF). However, naringenin prevented CSE-induced cilia damage via mechanisms such as the downregulation of cilia-related genes (e.g., RFX3, DNAI1, DNAH5, IFT88) and ciliary marker proteins such as DNAI2, FOXJ1, and β-tubulin IV, the upregulation of inflammatory factors (e.g., IL-6, IL-8, IL-13), ROS and MDA. IL-17 signaling pathway might be involved in the protective effect of naringenin on airway cilia. Additionally, the cAMP signaling pathway might also be related to the enhancement of CBF by naringenin.

CONCLUSION

In this study, we first found that naringenin reduces CSE-induced structural disruption of airway cilia in part via modulation of the IL-17 signaling pathway. Furthermore, we also found that naringenin enhances CBF by activating the cAMP signaling pathway. This is the first report to reveal the beneficial effects of naringenin on airway cilia and the potential underlying mechanisms.

Puerarin inhibits FUNDC1-mediated mitochondrial autophagy and CSE-induced apoptosis of human bronchial epithelial cells by activating the PI3K/AKT/mTOR signaling pathway

Increasing evidence suggests that the pathogenesis of chronic obstructive pulmonary disease (COPD) is associated with FUN14 domain protein 1 (FUNDC1)-mediated mitophagy. Recently, studies have reported that puerarin has protective effects against excessive oxidative damage in cells. Therefore, we hypothesized that puerarin may be involved in COPD progression via regulating FUNDC1 mediated mitophagy. We found that the viability of cigarette smoke extract (CSE)-stimulated human bronchial epithelial cells (HBECs) was enhanced and apoptosis was reduced after treatment with different concentrations of puerarin. Puerarin reversed mitochondrial membrane potential (MMP) levels and ATP content, and decreased reactive oxygen species (ROS) content in CSE stimulated HBECs. Moreover, puerarin significantly inhibited apoptosis related proteins, as well as the expression of mitophagy related proteins. After inhibition of FUNDC1 phosphorylation by protein phosphatase inhibitor (PH0321), puerarin restored MMP level, decreased ROS content, promoted ATP synthesis, and downregulated autophagy related protein expression in HBECs. In addition, mitochondrial division inhibitor (Mdivi) inhibited the expression of autophagy related proteins and reduced apoptosis after blocking cell autophagy, which was the same as the inhibition of puerarin. Finally, puerarin activated the PI3K/Akt/mTOR signaling pathway to participate in COPD progression by up regulating the phosphorylation levels of PI3K, Akt and mTOR.

MicroRNA-221-3p alleviates cell apoptosis and inflammatory response by targeting cyclin dependent kinase inhibitor 1B in chronic obstructive pulmonary disease

As a chronic bronchitis or emphysema featured by airflow obstruction, chronic obstructive pulmonary disease (COPD) can further develop into respiratory failure and pulmonary heart diseases. MicroRNAs (miRNAs) are crucial mediators in COPD. Nevertheless, the specific role and molecular mechanism of microRNA-221-3p (miR-221-3p) in COPD are unclear. This research aimed to probe into the role of miR-221-3p in COPD. Bioinformatics analysis and a series of assays including western blot, luciferase reporter, reverse transcription quantitative polymerase chain reaction, flow cytometry, cell counting kit-8 and enzyme linked immunosorbent assay were used to explore the functions and mechanism of miR-221-3p in COPD. First, miR-221-3p level was validated to be lowly expressed in the lung tissues of COPD patients and 16HBE cells stimulated by cigarette smoke extract (CSE). Functionally, miR-221-3p overexpression inhibited inflammatory response and apoptosis in CSE-treated 16HBE cells. Moreover, we predicted 5 potential targets of miR-221-3p and found that miR-221-3p shared binding site with cyclin dependent kinase inhibitor 1B (CDKN1B). CDKN1B was targeted by miR-221-3p in CSE-treated 16HBE cells. CDKN1B was negatively modulated by miR-221-3p. Finally, rescue experiments demonstrated that overexpressed CDKN1B counteracted the influences of miR-221-3p on apoptosis and inflammatory response in CSE-treated 16HBE cells. Our data showed that miR-221-3p alleviated cell apoptosis and inflammatory response via targeting CDKN1B in an in vitro model of COPD.

Primary cilia in corneal development and disease

As a transparent avascular tissue located at the front of the eyeball, the cornea is an important barrier to external damage. Both epithelial and endothelial cells of the cornea harbor primary cilia, which sense changes in the external environment and regulate intracellular signaling pathways. Accumulating evidence suggests that the primary cilium regulates corneal development in several ways, including participation in corneal epithelial stratification and maintenance of corneal endothelial cell morphology. In addition, the primary cilium has been implicated in the pathogenesis of several corneal diseases. In this review, we discuss recent findings that demonstrate the critical role of the primary cilium in corneal development. We also discuss the link between ciliary dysfunction and corneal diseases, which suggests that the primary cilium could be targeted to treat these diseases.