Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, PL30-387, Krakow, Poland; Doctoral School of Exact and Natural Sciences, Jagiellonian University, Łojasiewicza 11, PL30-348, Krakow, Poland.
Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, PL30-387, Krakow, Poland.
Fish Shellfish Immunol. 2023 Sep;140:108979. doi: 10.1016/j.fsi.2023.108979. Epub 2023 Jul 31.
The circadian clock mechanism, which is evolutionarily conserved across various organisms, plays a crucial role in synchronizing physiological responses to external conditions, primarily in response to light availability. By maintaining homeostasis of biological processes and behavior, the circadian clock serves as a key regulator. This biological mechanism also coordinates diurnal oscillations of the immune response during infections. However there is limited information available regarding the influence of circadian oscillation on immune regulation, especially in lower vertebrates like teleost fish. Therefore, the present study aimed to investigate the effects of light and the timing of infection induction on the antiviral immune response in zebrafish. To explore the relationship between the timing of infection and the response activated by viral pathogens, we used a zebrafish model infected with tilapia lake virus (TiLV). Our findings demonstrated that light availability significantly affects the antiviral immune response and the functioning of the molecular clock mechanism during TiLV infection. This is evident through alterations in the expression of major core clock genes and the regulation of TiLV replication and type I IFN pathway genes in the kidney of fish maintained under LD (light-dark) conditions compared to constant darkness (DD) conditions. Moreover, infection induced during the light phase of the LD cycle, in contrast to nocturnal infection, also exhibited similar effects on the expression of genes associated with the antiviral response. This study indicates a more effective mechanism of the zebrafish antiviral response during light exposure, which inherently involves modification of the expression of key components of the molecular circadian clock. It suggests that the zebrafish antiviral response to infection is regulated by both light and the circadian clock.
生物钟机制在各种生物中都得到了进化上的保守，在使生理反应与外部条件同步方面发挥着关键作用，主要是对光的可用性做出反应。通过维持生物过程和行为的内稳态，生物钟作为关键调节剂发挥作用。这种生物机制还协调了感染期间免疫反应的昼夜波动。然而，关于生物钟振荡对免疫调节的影响，特别是在像硬骨鱼这样的低等脊椎动物中，信息有限。因此，本研究旨在调查光照和感染诱导时间对斑马鱼抗病毒免疫反应的影响。为了探索感染时间与病毒病原体激活的反应之间的关系，我们使用感染罗非鱼湖病毒（TiLV）的斑马鱼模型进行研究。我们的研究结果表明，光照可用性显著影响 TiLV 感染期间的抗病毒免疫反应和分子钟机制的功能。这可以通过在 LD（光照-黑暗）条件下与连续黑暗（DD）条件下相比，主要核心时钟基因的表达变化以及 TiLV 复制和 I 型 IFN 途径基因的调节来证明。此外，与夜间感染相比，在 LD 周期的光照阶段诱导的感染也对与抗病毒反应相关的基因的表达产生了类似的影响。这项研究表明，在光照暴露下，斑马鱼抗病毒反应具有更有效的机制，这本质上涉及分子生物钟关键组成部分表达的修饰。它表明，斑马鱼对感染的抗病毒反应受光和生物钟的双重调节。
