Mycobacterium tuberculosis Rv0102-regulated copper uptake facilitates bacterial escape from phagolysosome
The host restricts Mycobacterium tuberculosis (Mtb) access of transition metal ions to inhibit its growth. Cu is essential for the survival of Mtb, but Cu excess is toxic. During co-evolution, Mtb has developed various mechanisms to maintain copper homeostasis. In this report, we firstly found Mtb Rv0102 encoded membrane protein is critical for Mycobacterium Cu uptake. The intracellular Cu level of M. smegmatis (Ms) Rv0102 homolog MSMEG_4702 knockout strain decreased threefold than the wild type, the deletion mutant was more tolerant to higher Cu level. This indicates that Rv0102 is significant for Cu homeostasis and resistance to Cu toxicity. Knocking out the homologous gene MMAR_0267 in M. marinum (Mm) also enhanced its virulence in zebrafish and improved its survival within macrophages. In THP-1 cells infected with Mm, Mm MMAR_0267 deletion mutants' intracellular survival increased fourfolds and accompanied by less cell apoptosis. Cu deficiency down-regulates the transcription of the M. marinum virulence factor CFP-10, dampening the STING cytosolic signaling in macrophages, fewer IFN-ß and less cell apoptosis. These results suggest that Cu is an important factor in inducing cell apoptosis. In summary, mycobacteria can effectively counteract the host's early key nutritional immune mechanisms by regulating copper metabolism, to increase its virulence. Overall design: Injected zebrafish with WT, ?MMAR_0267 and ?MMAR_0267:: MMAR_0267 M. marinum.  Performed RNA-seq analysis of zebrafish livers.