Coral-associated bacterial extracts inhibit cellular NF-κB pathway

Marine natural products have recently been recognized as a promising source of NF-κB inhibitors. In this study, extracts of bacterial isolates from the coral Favis sp. were screened for NF-κB modulatory capability using an NF-κB luciferase reporter gene assay. The bacterial extracts had variable effects on NF-κB activity: from the 39 extracts tested, only one exhibited significant NF-κB inhibition and two caused NF-κB up regulation. In addition, we showed that coral bacteria New-33 extract inhibits NF-κB alternative pathway subunits in a non-cytotoxic manner. HPLC analysis confirmed the presence of a low molecular mass compound and NCBI megaBLAST revealed that the New-33 16S rRNA gene sequences are similar to Vibrio mediterranei. This specific modulation of the NF-κB by alternative pathway could contribute to therapeutic implications and also raises questions about host-symbiont interaction in the marine environment.