Comparative RNA-seq analysis of resistant subpopulations of U937 and J3T cells identifies CMG2 (or ANTXR2) as the membrane receptor for C. perfringens pore-forming toxin NetF

Small portions of U937 and J3T cells survived NetF exposure independently of the toxin concentration used. To test whether these surviving cells represented a resistant subpopulation, we kept these cells under toxin selection. After 6 passages under constant selective pressure using 1 µg/ml NetF, we indeed achieved subclones of U937 (U937-R) and J3T (J3T-R) cells that were resistant to the toxin. We then compared mRNA expression profiles of these resistant “subpopulations” with their original “wild type” counterparts to search for potentially downregulated receptor gene candidates. Strikingly, only four genes were significantly downregulated in both U937-R and J3T-R cells. Among these four, Capillary Morphogenesis Gene 2, also known as Anthrax Toxin Receptor 2 (CMG2 or ANTXR2), stood out as the most enriched hit and the only gene encoding for a membrane protein. The other three downregulated genes were the transcription regulators PRDM8, ZNF790 and CREB5. Due to their intracellular localization, we did not consider them as potential plasma membrane receptors for NetF.