[Effects of PM2.5 on phagocytic function of alveolar macrophages in chronic obstructive pulmonary disease mice].

OBJECTIVE: To investigate the effects of fine particulate matter with a mean aerodynamic diameter ≤2.5 µm (PM2.5) collected from Lanzhou city on phagocytic function of alveolar macrophages (AM) in chronic obstructive pulmonary disease (COPD) mice. METHODS: Forty male mice were randomly divided into four groups: healthy group, healthy PM2.5 group, COPD group and COPD PM2.5 group. COPD mice were established by cigarette smoking. PM2.5 (10 mg/kg) collected by air sampler was intratracheally instilled in healthy PM2.5 group and COPD PM2.5 group. Mice were sacrificed after 14 days, and alveolar macrophages (AM) were isolated. Mean fluorescence intensity (MFI) and the positive percent of alveolar macrophages engulfing flurescein isothiocyanate-labeled Escherichia coli (FITC-E.coli) (AM%) were detected by flow cytometry. Total antioxidative capacity (TAC) was measured by O-phenanthroline colorimetry. Malondialdehyde (MDA) was measured by thiobarbiturieacid colorimetry and myeloperoxidase (MPO) was measured by O-dianisidine colorimetry. RESULTS: The peak inspiratory flow (PIF), peak expiratory flow (PEF) and dynamic compliance (Cdyn) of COPD group were significantly lower than healthy control group. The pathology of COPD group showed disruption of alveolar septa, formation of emphysema, and that the number of alveoli had a significant reduction. The MFI and AM% in COPD group were significant lower than healthy group (14.1±1.7 vs 43.2±6.1, 9.2%±2.3% vs 69.1%±8.3%)(all P<0.01). Comparing to healthy group and COPD group, the MFI and AM% in healthy PM2.5 group (20.3±4.5, 40.4%±4.4%) and COPD PM2.5 group (7.5±1.3, 6.0%±2.2%) were respectively lowered. The level of TAC in COPD group was significantly lower than healthy group [(3.10±0.64) vs (15.43±0.69)U/mg], the levels of MDA and MPO in COPD group were higher than healthy group[(2.72±0.13) vs (1.31±0.16) nmol/mg, (1.63±0.11) vs (0.92±0.13)U/g] (all P<0.01). In both healthy PM2.5 group and COPD PM2.5 group, the levels of TAC [(6.75±1.06), (2.34±0.61) U/mg] were lower than their corresponding control group; while the levels of MDA [(1.96±0.31), (3.20±0.19) nmol/mg] and the levels of MPO [(1.01±0.19), (1.74±0.13) U/g] were increased (all P<0.01). For the COPD group at baseline and after the intervention of PM2.5, the MFI and AM% showed positive correlation with the levels of TAC, and negative correlation with the levels of MDA , and negative correlation with the levels of MPO (all P<0.05). For health group at baseline and after the intervention PM2.5, the above relationships still existed (all P<0.05). CONCLUSION: PM2.5 can damage phagocytosis of AM and exacerbate oxidative stress in COPD mice, and AM phagocytosis impairment by PM2.5 is closely associated with oxidative stress.

Circ-PITX1 Promotes the Progression of Non-Small Cell Lung Cancer Through Regulating the miR-1248/CCND2 Axis.

BACKGROUND: Circular RNA (circRNA) is a key regulator of cancer, and it has been proved to be involved in the regulation of cancer progression including non-small cell lung cancer (NSCLC). Circ-PITX1 was found to be a significantly upregulated circRNA in NSCLC, and its role and potential mechanism in NSCLC progression deserve further investigation. METHODS: The expression levels of circ-PITX1, microRNA (miR)-1248 and cyclin D2 (CCND2) were examined by quantitative real-time PCR (qRT-PCR). Cell proliferation, apoptosis, cell cycle process, migration and invasion were determined using cell counting kit 8 (CCK8) assay, colony formation assay, flow cytometry, wound healing assay and transwell assay. Xenograft models were built to explore the role of circ-PITX1 in NSCLC tumor growth in vivo. The glycolysis and glutamine metabolism of cells were assessed by detecting the consumptions of glucose and glutamine, cell extracellular acidification rate (ECAR), and the productions of lactate, α-ketoglutaric acid (α-KG) and ATP. The protein levels of hexokinase 2 (HK-2), glutaminase 1 (GLS1) and CCND2 were tested by Western blot (WB) analysis. Dual-luciferase reporter assay and RIP assay were employed to verify the interaction between miR-1248 and circ-PITX1 or CCND2. RESULTS: Circ-PITX1 was upregulated in NSCLC and its silencing could inhibit the proliferation, migration, invasion, cell cycle process, glycolysis, glutamine metabolism, and promote the apoptosis of NSCLC cells in vitro, as well as reduced tumor growth in vivo. In the terms of mechanism, we found that circ-PITX1 could act as a sponge of miR-1248, and miR-1248 could target CCND2. In addition, miR-1248 inhibitor reversed the inhibitory effect of circ-PITX1 knockdown on NSCLC progression. Similarly, CCND2 overexpression also reversed the suppressive effect of miR-1248 on NSCLC progression. Moreover, circ-PITX1 positively regulated CCND2 expression by sponging miR-1248. CONCLUSION: Circ-PITX1 served as a sponge of miR-1248 to promote NSCLC progression by upregulating CCND2.

Effects of Astragalus and Codonopsis pilosula polysaccharides on alveolar macrophage phagocytosis and inflammation in chronic obstructive pulmonary disease mice exposed to PM2.5.

Astragalus and Codonopsis pilosula are used for their immunomodulatory and anti-inflammatory effects. Here, we investigated the effects of Astragalus polysaccharides (APS) and Codonopsis pilosula polysaccharides (CPP) on alveolar macrophage (AM) phagocytosis and inflammation in chronic obstructive pulmonary disease (COPD) associated with exposure to particulate matter with a mean aerodynamic diameter ≤2.5µm (PM2.5). A mouse model of COPD was established by cigarette smoke exposure. PM2.5 exposure was performed by inhalation of a PM2.5 solution aerosol. APS and CPP were administered intragastrically. COPD showed defective AM phagocytosis and increased levels of interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α in bronchoalveolar lavage fluid and serum. PM2.5 exposure aggravated the damage, and this effect was reversed by APS and CPP gavage. The results indicate that APS and CPP may promote defective AM phagocytosis and ameliorate the inflammatory response in COPD with or without PM2.5 exposure.