Transcriptome Analysis of Turbot (Scophthalmus maximus) Infected With Aeromonas salmonicida Reveals a Direct Effect on Leptin Synthesis as a Neuroendocrine Mediator of Inflammation and Metabolism Regulation

Aeromonas salmonicida subsp. is the causative agent of furunculosis, a disease affecting numerous fish species worldwide. It highly pathogenic bacterium for turbot, whose farming production represents an important economic activity in several European countries and China. To better understand response this organism to A. , we conducted RNA-Seq analysis head kidney from experimentally infected uninfected turbot juveniles at 24 hours post-infection (hpi). As expected, among differentially expressed genes (DEGs) between fish, observed modulation multitude immune-related but also high representation linked metabolism. Interestingly, one most upregulated was that encoding hormone leptin. Leptin multifunctional hormone/cytokine has been shown play roles immune system, stress response, food intake, metabolism energy balance. We used recombinant human leptin elucidate its role during infection with (anorexigenic activity, ability modulate effect on survival bacterial load infection). found intraperitoneal administration able alter bacteria level, especially metabolic which resulted higher rate without load. Based this, hypothesized could offer great potential as therapeutic treatment furunculosis outbreaks by reducing impact sepsis. Our results reveal complex interplay regulation inflammation.