Tissue- and time-dependent modulation of JAK/STAT pathway genes in Tenebrio molitor during Listeria monocytogenes infection.

Listeria monocytogenes is a facultative intracellular pathogen capable of direct intercellular transmission, enabling it to evade extracellular immune defenses and modulate host–pathogen interactions. This study examined the temporal and tissue-specific expression patterns of five genes associated with the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway in the insect host Tenebrio molitor following L. monocytogenes infection. Post-infection, whole body, gut, and Malpighian tubules were dissected at defined time points to assess differential gene expression. A significant induction of multiple JAK/STAT pathway genes was observed across all examined tissues. In whole-body samples, the pathway activator Janus kinase Hopscotch exhibited marked upregulation (> 2 fold) at 12 h post-infection, indicating the onset of signaling activity. The regulatory genes SOCS stops (1.5 fold), SP555 (2.5 fold), and SOCS box protein-3 (> 3 fold) showed early activation at 3 h post-infection, suggesting rapid transcriptional modulation. In gut tissues, Hopscotch expression (> 4 fold) increased from 3 h post-infection and remained elevated through day 5, whereas SOCS box protein-3 exhibited (> 2 fold) the strongest regulatory effect, followed by moderate expression of SOCS stops (max 2 fold) and minimal SP555 activity. In Malpighian tubules, Hopscotch (> 2 fold) and the transcription factor Stat92E (> 4 fold) were upregulated from 6 h post-infection and remained elevated until day 5. SOCS box protein-3 again demonstrated predominant regulatory activity, while SOCS stops and SP555 showed no detectable expression. Collectively, these findings indicate that JAK/STAT pathway gene expression in T. molitor during L. monocytogenes infection is both time-dependent and tissue-specific, reflecting a finely tuned immune response to intracellular bacterial invasion.