RNA-Seq Revealed the Effects of Cold Stress on Different Brain Regions of Leiocassis longirostris

Cold shock represents a prevalent but harmful environmental stress factor that poses significant threats to fish survival and reproductive success. In fish, the brain acts as a central regulator of thermoregulatory processes. Nevertheless, how different brain regions respond molecularly to cold exposure remains largely unknown. To address this, this study systematically investigated the effects of acute cold stress on five specific brain regions of Leiocassis longirostris using RNA-seq. The findings demonstrated that all five brain regions were significantly impacted by cold treatment, with the mesencephalon (MB) showing the most substantial changes. GO and KEGG enrichment analyses indicated that cold stress disrupted processes including gene expression regulation, circadian rhythms, and immune function within brain tissues. Through Weighted Gene Co-Expression Network Analysis (WGCNA), the MB was identified as the core responsive region, and the brain's reaction to cold stress was strongly correlated with circadian rhythm, spliceosome, and ubiquitination. In summary, our investigation demonstrates that the MB represents a principal region for cold stress response in L. longirostris, involving alterations in circadian clocks, immune function, and inflammatory responses, alongside suppression of gene expression processes and ubiquitination-mediated proteolysis.