Background Increased lung macrophage numbers in COPD may arise from upregulation of blood monocyte recruitment into the lungs. macrophages was reduced in COPD compared to NS. All alveolar macrophages from COPD and S expressed the anti-apoptosis marker BCL2; this protein was not present in non-smokers or COPD ex-smokers. Conclusion COPD monocytes show decreased migratory ability despite increased CCR5 expression. Increased COPD lung macrophage numbers may be due to delayed apoptosis. Electronic supplementary material The online version of this article (doi:10.1186/s12931-017-0569-y) contains supplementary material, which is available to authorized users. Keywords: COPD, Monocytes, CCR5, Chemotaxis, Interleukin-6 Background Monocytes can be recruited from the blood buy 136236-51-6 into the tissues, whereupon differentiation into macrophages may occur . There are also tissue resident macrophages that replenish cell numbers by replication . A recent study demonstrated the presence of phenotypically different mononuclear phagocyte cell types in healthy human lungs that either originate from the lungs (pulmonary dendritic cells and alveolar macrophages) or from blood monocytes (monocyte derived cells and tissue monocyte/macrophages) . There are increased numbers of macrophages in the lungs of chronic obstructive pulmonary disease (COPD) patients ; these cells are involved in host defence, airway remodelling and parenchymal destruction . It has been suggested that increased lung macrophage numbers in COPD are due to increased recruitment of blood monocytes [5, 6]. Alternatively, cigarette smoke exposure induces the expression of anti-apoptotic genes in macrophages , and increased expression of anti-apoptotic proteins has been observed in COPD macrophages , suggesting that delayed apoptosis is a possible cause of macrophage accumulation in COPD. Furthermore, alveolar macrophages expressing the proliferation buy 136236-51-6 marker Ki67 have been observed in patients with interstitial lung disease , but whether increased macrophage accumulation in COPD occurs by self-renewal is not understood. Costa et al reported increased migration of COPD peripheral blood mononuclear cells towards C-X-C motif chemokine receptor 3 (CXCR3) and C-C motif chemokine receptor 5 (CCR5) ligands using single chemokines for migration experiments . Such experiments, however do not reflect the complex mixture of chemoattractants present in the lungs [10C15]. Physiologically relevant complex supernatants, such as those obtained from induced sputum could be used to further investigate the migratory ability of COPD monocytes. CCR5 is the receptor for the monocyte chemoattractant C-C motif chemokine ligand 3 (CCL3) . Studies using induced sputum and bronchoalveolar lavage have shown that CCR5 ligand levels are increased in the lungs of COPD GDF5 patients, suggesting a role for CCR5 signalling in the recruitment of monocytes into COPD lungs [12, 13, 16, 17]. Peripheral blood monocytes can be classified into 3 subtypes according to their expression of CD14 (LPS receptor) and CD16 (FcRIII receptor): CD14++CD16- (Classical), CD14+CD16+ (Intermediate) and CD14-CD16++ (Non-Classical) . Increased numbers of pro-inflammatory CD14+CD16+ monocytes are buy 136236-51-6 found in chronic inflammatory disease states such as rheumatoid arthritis . Furthermore, CD14+CD16+ cells have the greatest surface expression of CCR5 [1, 19]. Monocyte subsets in COPD, and their buy 136236-51-6 expression of CCR5, have not been previously reported. buy 136236-51-6 CCR5 expression is upregulated by interleukin-6 (IL-6) , a cytokine which trans-signals through a soluble receptor sIL-6R . Plasma IL-6 levels are increased in a subset of stable COPD patients  and during COPD exacerbations . The systemic levels of sIL-6R have not been investigated in COPD; increased systemic IL-6/sIL-6R signalling in COPD could upregulate blood monocyte CCR5 expression, thereby promoting monocyte recruitment into the lungs. We have investigated COPD blood monocyte recruitment with two major objectives.
Although right ventricular failure (RVF) is the hallmark of pulmonary arterial hypertension (PAH) the mechanism of RVF is unclear. with folic acid (FA) alleviates ROS generation maintains MMP/TIMP balance and regresses interstitial fibrosis we used a mouse model of pulmonary artery constriction (PAC). After surgery mice were given FA in their drinking water (0.03 g/l) LGD1069 for 4 wk. Production of ROS in the right ventricle (RV) was measured using oxidative fluorescent dye. The level of MMP-2 -9 and -13 and TIMP-4 autophagy marker (p62) mitophagy marker (LC3A/B) collagen interstitial fibrosis and ROS in the RV wall was measured. RV function was measured by Millar catheter. Treatment LGD1069 with FA decreased the pressure to 35 mmHg from 50 mmHg in PAC mice. Similarly RV volume in PAC LGD1069 mice was increased compared with the Sham group. A robust increase of ROS was observed in RV of PAC mice which was decreased by treatment with FA. The protein level of MMP-2 -9 and -13 was increased in RV of PAC mice in comparison with that in the sham-operated mice whereas supplementation with FA abolished this effect and mitigated MMPs levels. The protein level of TIMP-4 was decreased in RV of PAC mice compared with the Sham group. Treatment with FA helped PAC mice to improve the level of TIMP-4. To further support the claim of mitophagy occurrence during RVF the levels of LC3A/B and p62 were measured by Western blot and immunohistochemistry. LC3A/B was increased in RV of PAC mice. Similarly increased p62 protein level was observed in RV of PAC mice. Treatment with FA abolished this effect in PAC mice. These results suggest that FA treatment improves MMP/TIMP balance and ameliorates mitochondrial dysfunction that results in protection of RV failure during pulmonary hypertension. < 0.05) Tukey's multiple comparison test was used to compare CCR5 group means and were considered significant if < 0.05. RESULTS Level of fibrosis. Histological analysis of collagen was performed in the slices of RV. The intensity of trichrome blue stain demonstrated development of significant collagen accumulation in the RV samples from PAC mice hearts compared with those from the Sham-operated mice (Fig. 1). Treatment with folic acid mitigated the formation of fibrosis in the LGD1069 RVs from PAC + folic acid group (Fig. 1). RV wall thickness in PAC mice was thinner compared with that in PAC mice treated with folic acid (Fig. 1). RV was dilated in PAC mice compared with that in sham-operated mice (Fig. 1). Treatment with folic acid decreased RV dilatation in PAC mice (Fig. 1). Fig. 1. Pulmonary artery constriction (PAC)-induced collagen deposition in the right ventricle (RV). and Table 1). Treatment with folic acid improved myocyte properties in PAC mice (Fig. 2and Table 1). PAC significantly impaired contractility of isolated cardiomyocytes (Fig. 2 and and C). Fig. 2. PAC-induced myocyte contractility changes. A: examples of myocytes isolated from Sham Sham + FA PAC and PAC + FA mice. B: examples of cell shortening traces in myocytes from the above mentioned groups. C: changes in percent peak shortening presented … RVF-induced LGD1069 increased ROS production. Production of ROS in the RV was measured using oxidative fluorescent dye DHE. The extent of DHE fluorescence indicated ROS production (Fig. 3). A robust increase of DHE fluorescence was observed in PAC mice (Fig. 3). Treatment with folic acid ameliorated DHE fluorescence intensity in PAC + folic acid mice it was lower compared with that in PAC mice but it was still higher than in age-matched sham-operated mice (Fig. 3). Fig. 3. PAC-induced superoxide production in mice RV. Superoxide production was detected in situ by staining heart tissue with the superoxide sensitive dye DHE (red fluorescence). A: examples of RV images in samples from wild-type (WT) WT + FA PAC and PAC … Role of MMPs during RVF. Representative Immunoblots for MMPs are shown in Fig. 4A. The protein levels of MMP-2 -9 and -13 were robustly increased in RVs of PAC mice compared with those in RV of the sham-operated mice (Fig. 4A). Supplementation with folic acid reversed this effect in RVs of PAC mice (Fig. 4A). Fig. 4. Effect of FA on matrix metalloproteinase (MMP)/tissue inhibitor of metalloproteinases (TIMP) ration mice. A: examples of.