Department of Zoology, University of Lucknow, Lucknow, Uttar Pradesh 226007, India. Electronic address: https://twitter.com/JyotiTiwari2711.
Department of Zoology, University of Lucknow, Lucknow, Uttar Pradesh 226007, India. Electronic address: https://twitter.com/sayantansur008.
Comp Biochem Physiol A Mol Integr Physiol. 2023 May;279:111381. doi: 10.1016/j.cbpa.2023.111381. Epub 2023 Jan 29.
The transcriptional regulation of innate immune function across annual life history states (LHS) remains obscure in avian migrants. We, therefore, investigated this in a migratory passerine songbird, redheaded bunting (Emberiza bruniceps), which exhibits long-distance vernal migration from India to Central Asia. We exposed the birds (N = 10) to differential photoperiodic conditions to induce a non-migratory (NM), pre-migratory (PM), migratory (MIG), and refractory (REF) state, and performed gene expression assays of melatonin receptors (MEL1A and MEL1B), and innate immunity-linked genes (IL1B, IL6, TLR4, and NFKB) in spleen and blood. We found a significant reduction in splenic mass and volume, and a parallel increase in fat accumulation, and testicular growth in birds under migratory state. The gene expression assay revealed an upregulation of MEL1A and MEL1B mRNA levels in both the tissues in MIG. Additionally, we found a nocturnal increase of splenic IL1B expression, and IL1B, IL6, and TLR4 expression in the blood. The mRNA expression of melatonin receptors and proinflammatory cytokine showed a positive correlation. These results suggest that melatonin relays the photoperiodic signal to peripheral immune organs, which shows LHS-dependent changes in mRNA expression of immune genes.
鸟类迁徙者在不同年度生活史阶段（LHS）的固有免疫功能的转录调控仍不清楚。因此，我们以具有远距离春季迁徙习性的雀形目鸣禽红头朱雀（Emberiza bruniceps）为研究对象，探讨了这一问题。我们通过不同的光周期条件暴露鸟类（N=10），以诱导非迁徙（NM）、迁徙前（PM）、迁徙（MIG）和休眠（REF）状态，并对褪黑素受体（MEL1A 和 MEL1B）和与固有免疫相关的基因（IL1B、IL6、TLR4 和 NFKB）在脾脏和血液中的表达进行了测定。我们发现，在迁徙状态下，鸟类的脾脏质量和体积显著减小，脂肪堆积和睾丸生长增加。基因表达分析显示，MIG 状态下两种组织中的 MEL1A 和 MEL1B mRNA 水平均上调。此外，我们发现，夜间脾脏中 IL1B 的表达增加，血液中 IL1B、IL6 和 TLR4 的表达增加。褪黑素受体和促炎细胞因子的 mRNA 表达呈正相关。这些结果表明，褪黑素将光周期信号传递到外周免疫器官，这显示出免疫基因的 mRNA 表达具有 LHS 依赖性变化。
