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Objective:To investigate the effects of Chlamydia muridarum ( Cm) respiratory tract infection on the infiltration and polarization of alveolar macrophages (AMs) and pulmonary interstitial macrophages (IMs). Methods:A C57BL/6 mouse model of Cm respiratory tract infection was established through nasal inhalation. Flow cytometry was used to detect AMs (CD45 + F4/80 + CD11c + ) and IMs (CD45 + F4/80 + CD11c -) in lung tissues at 0, 3, 7 and 14 d after Cm respiratory tract infection. The proportions of M1 (CD80 + , CD86 + , MHCⅡ + , iNOS + ) and M2 (CD206 + , Arg1 + ) macrophages in AMs and IMs were also detected. Results:(1) Cm respiratory tract infection induced the infiltration of AMs and IMs. Compared with the uninfected group (0 d), the proportions and the numbers of AMs and IMs of were significantly increased 3 d after infection ( P<0.05, P<0.01). The numbers of AMs and IMs reached the peak 7 d after infection ( P<0.001). (2) Compared with the uninfected group, the proportions of CD80 + and CD86 + cells in AMs were significantly up-regulated 3 d after infection ( P<0.05, P<0.01); the proportion of MHCⅡ + cells in AMs increased after infection and reached the peak at 14 d ( P<0.05), while the proportion of CD206 + cells decreased after infection ( P<0.05). (3) Compared with the uninfected group, the proportions of CD80 + and CD86 + cells in IMs were increased 3 d after infection ( P<0.05, P<0.001) and the proportion of MHCⅡ + cells was significantly increased 14 d after infection ( P<0.01), while there was no significant change in the proportion of CD206 + cells. (4) In AMs, the proportion of iNOS + cells increased continuously after infection ( P<0.01), while the proportion of Arg1 + cells decreased continuously after infection, especially at 7 d and 14 d ( P<0.05). In IMs, the proportion of iNOS + cells reached the peak at 7 d ( P<0.001), but the proportion of Arg1 + cells showed no significant change after infection. Conclusions:Cm respiratory tract infection induced the infiltration of AMs and IMs, stimulated the polarization of AMs and IMs towards the M1 phenotype and weakened the polarization of AMs to M2 macrophages, but had no significant influence on the polarization of IMs towards the M2 phenotype.
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This study investigated the heterogeneity and plasticity of porcine alveolar macrophages (PAM) and pulmonary interstitial macrophages (IM) isolated from healthy pigs, including phenotype, function and gene expression. Dynamic changes of nitric oxide (NO) levels secreted by PAM and IM with stimulation of different doses of lipopolysaccharide (LPS) were investigated by Griess method, and the viability of the PAM and IM cells was investigated by MTT assay. Flow cytometry, fluorescence quantitative PCR and ELISA techniques were used to measure cell phenotype, gene expression and cytokine secretion, respectively. The PAM and IM cells in normal healthy pigs showed heterogeneity with 95.42±1.51% and 31.99±5.84% of CD163+ macrophage, respectively. The NO level in IM was significantly higher versus PAM after LPS treatment. Consistently, the ratio of Arg I/iNOS in IM was much lower than that in PAM, suggesting that the PAM belong to M2 macrophages and the IM belong to M1 macrophages. The PAM and IM cells in normal healthy pigs also showed plasticity. The Arg I/iNOS ratio and TIMP1/MMP12 ratio were significantly decreased in LPS- or LPS+IFNγ-treated PAM and IM, suggesting that cells were polarized towards M1 macrophages under LPS or LPS+IFNγ stimulation. On the contrary, IL-4 and IL-13 stimulation on PAM and IM lead to M2 polarization. A similar result was found in IL-1ß gene expression and TNFα secretion. In conclusion, porcine macrophages have shown heterogeneity and plasticity on polarization under the stimulation of LPS, IFNγ, IL-4 and IL-13.
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0.05).But PMA increased and SC-3088 decreased cAMP content and PKA activity in LPS-stimulated rat PIMs(P
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0.05); but significantly increased cAMP content and PKA activity at high concentration [(10-9~10-5) mol?L-1] (compared with normal control group:P
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AIM: To investigate the binding characteristics of cholecystokinin receptors in rat pulmonary interstitial macrophages (PIMs). METHODS: The PIMs were isolated from rat lung tissues, purified using the collagenase digestion method combined with alveolar lavage and pulmonary vessel perfusion. The PIM membrane was obtained by supercentrifuge. Receptors for CCK in PIMs were examined using [~3H] labeled CCK-8S as ligand. The specificity of [~3H]-CCK-8S binding to PIMs membrane and the subtypes of CCK receptors were determined by competitive inhibition experiments with CCK-8S, CCK-A and CCK-B receptors selective antagonists (CR1409 and CR2945). The effects of time and incubation temperature on the specific binding were also observed. RESULTS: The specific binding of [~3H]-CCK-8S was not detected in normal rat PIMs, but was detected in the rat administrated with LPS for 48 h. The capacity of ligand-receptor binding was dependent on the incubation temperature and time. Scatchard analysis of the saturation curves suggested that the presence of CCK receptors with high affinity [Kd=(0.68?0.28)mmol/L] and low binding capacity [Bmax=(32.50?2.70) pmol?g~(-1) protein] in PIMs. By means of competitive inhibition studies, the specific binding of [~3H]-CCK-8S to rat PIMs was inhibited by unlabelled CCK-8S [IC_(50)=(3.20?1.13) nmol/L], CCK-AR specific antagonist CR 1 409 [IC_(50)=(0.19?0.06)?mol/L] and CCK-BR specific antagonist CR 2945[IC_(50)=(2.30?0.80)nmol/L]. CONCLUSION: These results suggest the presence of two subtypes of CCK-AR and CCK-BR and provide a structural basis for CCK to play a pivotal role in PIMs.
