Wilson M E, McCandless E E, Olszewski M A, Robinson N Edward
Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824, USA.
Global Therapeutics Research, Zoetis, 333 Portage St, Kalamazoo, MI, 49007, USA.
Vet J. 2020 Feb;256:105436. doi: 10.1016/j.tvjl.2020.105436. Epub 2020 Feb 11.
Because the alveolar macrophage (AM) phenotype of horses with severe equine asthma (SEA) is unknown, the cytokines expressed by M1- and M2-polarized AM were determined and the hypothesis that natural hay/straw challenge (NC) induces divergent AM phenotypes in control horses and horses with SEA was tested. Macrophages from control horses were activated either with eIFNγ + lipolysaccharide (LPS) or eIL-4 to characterize M1- or M2-polarized AM gene expression, respectively and determine the response of polarized cells to pathogen-associated molecular patterns (PAMPS): LPS, zymosan, peptidoglycan and hay dust. Subsequently, gene expression was explored in AM of control horses and horses with SEA at pasture and after NC. M1 polarization increased expression of pro-inflammatory cytokines (TNFα, IL-8, IL-12p40), IL-10, and CD80. M2 polarization increased CD206 and down-regulated arginase-II and IL-10. Expression of pro-inflammatory cytokines and CD80 in response to PAMPS was further increased by M1 pre-polarization whereas M2 pre-polarization down-regulated expression of pro-inflammatory cytokines and IL-10 but increased CD206. In horses with SEA, AMs had elevated expression of IL-10 both at pasture and after NC, but only after NC in control horses. CD206 expression increased in both groups during NC. At pasture, stimulation by PAMPS augmented expression of IL-8 and IL-10 in horses with SEA compared to control horses. NC eliminated this difference by selectively increasing expression of IL-10 in control horses. A fundamental shift in the macrophage phenotype in SEA is supported by consistently elevated production of IL-10. A similar non-canonical phenotype develops temporarily in control horses upon NC suggesting that AMs in horses with SEA have lost the ability to respond dynamically to environmental cues.
由于患有严重马哮喘（SEA）的马的肺泡巨噬细胞（AM）表型尚不清楚，因此测定了M1和M2极化的AM表达的细胞因子，并检验了天然干草/稻草激发（NC）在对照马和患有SEA的马中诱导不同AM表型的假设。分别用eIFNγ+脂多糖（LPS）或eIL-4激活对照马的巨噬细胞，以表征M1或M2极化的AM基因表达，并确定极化细胞对病原体相关分子模式（PAMP）的反应：LPS、酵母聚糖、肽聚糖和干草粉尘。随后，研究了对照马和患有SEA的马在牧场和NC后的AM中的基因表达。M1极化增加了促炎细胞因子（TNFα、IL-8、IL-12p40）、IL-10和CD80的表达。M2极化增加了CD206的表达，并下调了精氨酸酶-II和IL-10。M1预极化进一步增加了对PAMP反应的促炎细胞因子和CD80的表达，而M2预极化下调了促炎细胞因子和IL-10的表达，但增加了CD206的表达。在患有SEA的马中，AM在牧场和NC后IL-10的表达均升高，但仅在对照马的NC后升高。两组在NC期间CD206表达均增加。在牧场，与对照马相比，PAMP刺激增加了患有SEA的马中IL-8和IL-10的表达。NC通过选择性增加对照马中IL-10的表达消除了这种差异。IL-10的持续升高支持了SEA中巨噬细胞表型的根本转变。对照马在NC后暂时出现类似的非经典表型，这表明患有SEA的马中的AM已失去对环境线索动态反应的能力。
