ABSTRACT
Objective: Chronic pulmonary inflammation caused by long-term smoking is the core pathology of COPD. Alveolar macrophages (AMs) are involved in the pulmonary inflammation of COPD. The accumulation of damaged materials caused by impaired autophagy triggers inflammatory response in macrophages. As a key transcription regulator, transcription factor EB (TFEB) activates the transcription of target genes related autophagy and lysosome by binding to promoters, whereas it is unclarified for the relationship between inflammatory response induced by cigarette smoke extract (CSE) and TFEB-mediated autophagy. Thus, we investigated the role of TFEB-mediated autophagy in inflammatory response induced by CSE in NR8383 cells, and to explore its potential mechanism. Methods: Based on cell viability and autophagy, cells treated with 20% concentration of CSE for 24 h were selected for further studies. Cells were divided into control group, chloroquine (CQ, the autophagy inhibitor) group, CSE group, CSE + rapamycin (the autophagy inducer) group and CSE + fisetin (the TFEB inducer) group. The levels of tumor necrosis factor α (TNF-α), interleukin 1ß (IL-1ß), and IL-6 in supernatant were detected by ELISA kits. The protein expressions were tested by western blot. The intensity of fluorescence of Lysosome-associated membrane protein 1 (LAMP1) and TFEB was detected by immunofluorescence. Lyso-Tracker Red staining was applied to detect the lysosome environment. Results: CSE inhibited the cell viability, increased the contents of TNF-α, IL-1ß, IL-6, the ratio of LC3II/I, and the level of P62 protein. Besides, CSE decreased the fluorescence intensity of LAMP1 protein and Lyso-Tracker Red staining, as well as the ratio of nucleus/cytosol of TFEB protein. Activating autophagy with rapamycin alleviated CSE-induced inflammatory response. The activation of TFEB via fisetin alleviated CSE-induced autophagy impairment and lysosomal dysfunction, thus alleviated inflammatory response in NR8383 cells. Conclusion: CSE-induced inflammatory response in NR8383 cells, which may be related to the inhibition of TFEB-mediated autophagy.
Subject(s)
Cigarette Smoking , Pulmonary Disease, Chronic Obstructive , Cigarette Smoking/adverse effects , Tumor Necrosis Factor-alpha , Interleukin-6 , Autophagy , NicotianaABSTRACT
Xiaoqinglong decoction (XQLD), a classic prescription of Traditional Chinese Medicine, has already been used clinically to cure acute lung injury (ALI), but its mechanism remains unclear. This subject aimed to explore the preventive role of XQLD in septic ALI rats besides its effects on angiotensin-converting enzyme (ACE)2 and its downstream factors. After, respectively, administrated with different concentrations of XQLD (6.25 g/kg/d, 12.5 g/kg/d, 25 g/kg/d) for 5 days and dexamethasone (DEX, 1 mg/kg) for 0.5 h, the rat models of ALI were established by intraperitoneal injection of lipopolysaccharide (LPS, 5 mg/kg) for 24 h. All rats were evaluated by lung function test, arterial blood gas analysis, morphological observation, lung wet/dry (W/D) ratio, and the lung injury score. The levels of malonaldehyde (MDA), superoxide dismutase (SOD), interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, and angiotensin (Ang) (1-7) in the lung were measured through biochemical and ELISA kits. The expressions of angiotensin-converting enzyme (ACE)2, mitochondrial assembly receptor (MasR), and nuclear factor (NF)-κB in lung tissue were detected by qRT-PCR and western blotting. Positive reaction cells of MasR were observed by immunohistochemistry. The results show that XQLD significantly ameliorated septic lung injury including edema and hemorrhage, as well as improved pulmonary function and arterial blood gas. Furthermore, XQLD markedly decreased the levels of IL-1ß, TNF-α, MDA, and NF-κB while increased the levels of SOD, Ang (1-7), ACE2, and MasR in septic ALI rats. Pearson correlation showed that the expressions of ACE2 were inversely related to IL-1ß, TNF-α, MDA, and NF-κB and positively correlated with SOD contents. Our data indicated that XQLD pretreatment alleviated inflammation and oxidative damage in septic ALI rats, which might be related to the up-regulation of ACE2-Ang (1-7)-MasR axis and inhibition of the NF-κB pathway.
ABSTRACT
OBJECTIVE: To observe the effect of electroacupuncture (EA) at "Zusanli" (ST36) and "Feishu" (BL13) on the activation and secretion of calcitonin gene-related peptide (CGRP) and 5-hydroxytryptamine (5-HT) of pulmonary neuroendocrine cells (PNECs) and inflammatory response in rats with chronic obstructive pulmonary disease (COPD), so as to explore its underlying mechanisms in treating COPD. METHODS: Male SD rats were randomly divided into normal control, COPD model and EA groups, with 7 rats in each group. The COPD model was established by forced inhale of cigarette smoke for 1 h in a self-made box (1 m×1 m×1 m in volume), twice daily for 12 weeks. EA (4 Hz/20 Hz, 1-3 mA) was applied at bilateral ST36 and BL13 acupoints for 30 min, once a day for 14 consecutive days. The pulmonary function including the forced vital capacity (FVC), forced expiratory volume at 0.1 second (FEV0.1), FEV0.3, FEV0.1/FVC and FEV0.3/FVC was detected using a lung function analyzer for small animals. The lung tissue was sampled for observing histopathological changes by using H.E. staining, for observing expression and distribution of PNECs by Grimelius silver staining, and for detecting the immunoactivity (integrated optical density) of CGRP and 5-HT by using immunohistochemistry. The contents of CGRP, 5-HT, tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and transforming growth factor-ß1 (TGF-ß1) in the bronchoalveolar lavage fluid (BALF) and lung tissue were detected by ELISA, and the correlations between TNF-α and CGRP, IL-1ß and CGRP, TNF-α and 5-HT, and IL-1ß and 5-HT levels were analyzed. The mRNA and protein expression levels of nerve fiber markers of CGRP and purinergic receptor P2X ligand gated ion channel 3 (P2X3) which dominate PNECs in the lung tissue were detected by real-time fluorescence quantitative PCR and Western blot, respectively. RESULTS: Compared with the normal control group, the levels of FVC, FEV0.1, FEV0.3, and the ratios of FEV0.1/FVC and FEV0.3/FVC were significantly decreased (P<0.05, P<0.01), while the immunoactivity of PNECs, CGRP and 5-HT, the contents of CGRP, 5-HT, TNF-α, IL-1ß and TGF-ß1 in the BALF and lung tissue, and the expression levels of CGRP and P2X3 mRNAs and proteins in the lung tissue significantly increased in the COPD model group (P<0.01, P<0.05). Following EA intervention, both the increased and decreased levels of all the indexes mentioned above were reversed (P<0.05, P<0.01) except FEV0.3. H.E. staining showed severe deformed bronchial lumen with thickened wall and alveolar septum, and obvious inflammatory cell infiltration and reduced number of alveolar lumen fusion in the COPD model group, which was mild in the EA group. A positive correlation was found between TNF-α and CGRP, IL-1ß and CGRP, TNF-α and 5-HT,IL-1ß and 5-HT levels in both BALF and lung tissues (P<0.01). CONCLUSION: EA at ST36 and BL13 can improve lung function and reduce inflammatory response in COPD rats, which may be related to its function in inhibiting the activation of PNECs and release of neuroactive substances.
