TnP and AHR-CYP1A1 Signaling Crosstalk in an Injury-Induced Zebrafish Inflammation Model

Aryl Hydrocarbon Receptor (AHR) signaling is crucial for regulating the biotransformation of xenobiotics and physiological processes like inflammation and immunity. Meanwhile, <i>Thalassophryne nattereri</i> Peptide (<i>Tn</i>P), a promising anti-inflammatory candidate from toadfish venom, demonstrates therapeutic effects through immunomodulation. However, its influence on AHR signaling remains unexplored. This study aimed to elucidate <i>Tn</i>P's molecular mechanisms on the AHR-cytochrome P450, family 1 (CYP1) pathway upon injury-induced inflammation in wild-type (WT) and <i>Ahr2</i>-knockdown (KD) zebrafish larvae through transcriptomic analysis and <i>Cyp1a</i> reporters. <i>Tn</i>P, while unable to directly activate AHR, potentiated AHR activation by the high-affinity ligand 6-Formylindolo [3,2-b]carbazole (FICZ), implying a role as a CYP1A inhibitor, confirmed by in vitro studies. This interplay suggests <i>Tn</i>P's ability to modulate the AHR-CYP1 complex, prompting investigations into its influence on biotransformation pathways and injury-induced inflammation. Here, the inflammation model alone resulted in a significant response on the transcriptome, with most differentially expressed genes (DEGs) being upregulated across the groups. <i>Ahr2</i>-KD resulted in an overall greater number of DEGs, as did treatment with the higher dose of <i>Tn</i>P in both WT and KD embryos. Genes related to oxidative stress and inflammatory response were the most apparent under inflamed conditions for both WT and KD groups, e.g., <i>Tnfrsf1a</i>, <i>Irf1b</i>, and <i>Mmp9</i>. <i>Tn</i>P, specifically, induces the expression of <i>Hspa5</i>, <i>Hsp90aa1.2</i>, <i>Cxcr3.3</i>, and <i>Mpeg1.2</i>. Overall, this study suggests an interplay between <i>Tn</i>P and the AHR-CYP1 pathway, stressing the inflammatory modulation through AHR-dependent mechanisms. Altogether, these results may offer new avenues in novel therapeutic strategies, such as based on natural bioactive molecules, harnessing AHR modulation for targeted and sustained drug effects in inflammatory conditions.