TY - JOUR
T1 - Functional phenotype of macrophages depends on assay procedures
AU - Chiang, Chi Shiun
AU - Chen, Fang Hsin
AU - Hong, Ji Hong
AU - Jiang, Pei Shin
AU - Huang, Hsiang Ling
AU - Wang, Chun Chieh
AU - Mcbride, William H.
PY - 2008/2
Y1 - 2008/2
N2 - Macrophages display different phenotypes that can switch in response to their micro-environment. In our earlier study (Chiang, C. S., Liu, W. C. and Jung, S. M., 2005. Compartmental responses after thoracic irradiation of mice: strain differences. Int. J. Radiat. Oncol. Biol. Phys. 62:862) on radiation-induced cytokine expression in lung lavage samples, there was a suggestion that the procedures used to harvest lung macrophages affected the profiles they expressed. To further explore this issue, we examined gene expression by cell populations, mainly macrophages, isolated by lavage from lung and peritoneal cavity following either in vivo or in vitro stimulation with LPS, IFN-γ or irradiation. We found that expression of mRNA for tumor necrosis factor-alpha, IL-1α/β and IL-6 varied several fold depending on whether the assay was performed on cells immediately after isolation or after in vitro manipulation. The relative level of inducible nitric oxide synthase (iNOS) to arginase I (Arg I), which is frequently used as index of the M1 versus M2 functional macrophage phenotype, also varied. LPS stimulation in vivo was able to change the profile from Arg I expression to one where the iNOS pathway became dominant, but was unable to do this in vitro. This contrasts with the ability of IFN-γ to generate an iNOS-dominant pathway in vitro, but not in vivo. This study cautions that the expression of inflammatory cytokines and the iNOS to Arg I ratio, which is often used as an index of their functional capacity, varies with the experimental conditions.
AB - Macrophages display different phenotypes that can switch in response to their micro-environment. In our earlier study (Chiang, C. S., Liu, W. C. and Jung, S. M., 2005. Compartmental responses after thoracic irradiation of mice: strain differences. Int. J. Radiat. Oncol. Biol. Phys. 62:862) on radiation-induced cytokine expression in lung lavage samples, there was a suggestion that the procedures used to harvest lung macrophages affected the profiles they expressed. To further explore this issue, we examined gene expression by cell populations, mainly macrophages, isolated by lavage from lung and peritoneal cavity following either in vivo or in vitro stimulation with LPS, IFN-γ or irradiation. We found that expression of mRNA for tumor necrosis factor-alpha, IL-1α/β and IL-6 varied several fold depending on whether the assay was performed on cells immediately after isolation or after in vitro manipulation. The relative level of inducible nitric oxide synthase (iNOS) to arginase I (Arg I), which is frequently used as index of the M1 versus M2 functional macrophage phenotype, also varied. LPS stimulation in vivo was able to change the profile from Arg I expression to one where the iNOS pathway became dominant, but was unable to do this in vitro. This contrasts with the ability of IFN-γ to generate an iNOS-dominant pathway in vitro, but not in vivo. This study cautions that the expression of inflammatory cytokines and the iNOS to Arg I ratio, which is often used as an index of their functional capacity, varies with the experimental conditions.
KW - Arginase
KW - Cytokines
KW - Nitric oxide synthase
UR - http://www.scopus.com/inward/record.url?scp=39049152573&partnerID=8YFLogxK
U2 - 10.1093/intimm/dxm137
DO - 10.1093/intimm/dxm137
M3 - 文章
C2 - 18096562
AN - SCOPUS:39049152573
SN - 0953-8178
VL - 20
SP - 215
EP - 222
JO - International Immunology
JF - International Immunology
IS - 2
ER -