RmpA drives metabolic reprogramming to modulate the phenotypic switch between hypermucoviscosity and biofilm formation in hypervirulent Klebsiella pneumoniae

Hypervirulent Klebsiella pneumoniae (hvKp) is a significant pathogen causing severe community-acquired infections. Its heightened virulence is largely attributed to the presence of a virulence plasmid, which enhances its pathogenicity. The plasmid-encoded regulator of mucoid phenotype A (RmpA) activates the expression of capsule locus genes, driving the hypermucoviscosity phenotype strongly associated with increased virulence. RmpA features a LuxR DNA-binding domain and a signaling-responsive domain, typical of proteins that regulate diverse biological processes. However, the precise regulatory mechanisms of RmpA in hvKp remain poorly understood. In this study, RNA sequencing (RNA-seq) analysis revealed that RmpA activates carbohydrate metabolism pathways while repressing pathways related to DNA replication, ribosome metabolism, and biofilm formation. Chromatin immunoprecipitation sequencing (ChIP-seq) analysis further confirmed RmpA’s potential role as a global regulator that not only enhances capsule production by activating transcripts within the capsule locus but also upregulates genes involved in sugar metabolism and transport, supplying essential precursors for capsule synthesis. RmpA modulates the phenotypic switch between hypermucoviscosity and biofilm formation by repressing type III fimbriae genes. Notably, overexpression of RmpA in Escherichia coli induced changes in multiple metabolic pathways. These findings position RmpA as a latent central regulator in hvKp, orchestrating metabolic pathways and phenotypic traits essential for virulence. • Regulator of mucoid phenotype A (RmpA) significantly activates and inhibits various metabolic pathways. • RmpA induces metabolic reprogramming to meet the specific energy and biosynthetic needs of capsular polysaccharide synthesis. • RmpA inhibits the expression of mrkABCDF cluster, controlling biofilm formation in hypervirulent Klebsiella pneumoniae. • Expression of RmpA in Escherichia coli perturbed diverse metabolic pathways.