Molecular and functional characterization of interleukin-1β in red drum (Sciaenops ocellatus) and its pivotal role in antibacterial immunity.

Abstract

As a critical early-stage pro-inflammatory cytokine, interleukin-1β (IL-1β) plays a critical role in modulating immune and inflammatory responses during infection. It mediates these effects by signaling through the interleukin-1 receptor (IL-1R), thereby regulating inflammation, antimicrobial activity, and the proliferation, differentiation, and death of immune cells. In this study, we identified IL-1β homologs, designated as SoIL-1β in red drum (Sciaenops ocellatus). Sequence analysis revealed that SoIL-1β was evolutionarily conserved among teleost fish. Expression pattern analysis showed that both il1β and il1r1 were constitutively expressed across healthy tissues and significantly upregulated in response to Vibrio harveyi infection and LPS stimulation. Functional experiments further confirmed that SoIL-1β could activate the NF-κB signaling pathway and upregulate the expression of inflammatory cytokines, as well as its receptor SoIL-1RI, with enhanced effects observed under LPS stimulation. Collectively, these findings highlight the essential role of SoIL-1β in the immune regulation and host defense of S. ocellatus, and contribute to a deeper understanding of IL-1 family cytokines functions and cytokine-receptor interaction network in teleost innate immunity.