A conserved switch controls virulence, sporulation, and motility in C. difficile

• Published in: PLoS pathogens 2024-05, Vol.20 (5), p.e1012224-e1012224
• Main Authors: DiCandia, Michael A, Edwards, Adrianne N, Alcaraz, Ysabella B, Monteiro, Marcos P, Lee, Cheyenne D, Vargas Cuebas, Germán, Bagchi, Pritha, McBride, Shonna M
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biology and Life Sciences; Care and treatment; Clostridioides difficile - genetics; Clostridioides difficile - metabolism; Clostridioides difficile - pathogenicity; Clostridium infections; Clostridium Infections - microbiology; Complications and side effects; Gene Expression Regulation, Bacterial; Gene mutations; Health aspects; Infections; Investigations; Medicine and Health Sciences; Mice; Microscopy; Molecular machines; Morbidity; Motility; Mutants; Pathogenesis; Phosphatases; Proteins; Regulation; Regulatory mechanisms (biology); Spores; Spores, Bacterial - genetics; Sporulation; Toxins; Virulence; Virulence (Microbiology)
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1012224

Spore formation is required for environmental survival and transmission of the human enteropathogenic Clostridioides difficile. In all bacterial spore formers, sporulation is regulated through activation of the master response regulator, Spo0A. However, the factors and mechanisms that directly regulate C. difficile Spo0A activity are not defined. In the well-studied Bacillus species, Spo0A is directly inactivated by Spo0E, a small phosphatase. To understand Spo0E function in C. difficile, we created a null mutation of the spo0E ortholog and assessed sporulation and physiology. The spo0E mutant produced significantly more spores, demonstrating Spo0E represses C. difficile sporulation. Unexpectedly, the spo0E mutant also exhibited increased motility and toxin production, and enhanced virulence in animal infections. We uncovered that Spo0E interacts with both Spo0A and the toxin and motility regulator, RstA. Direct interactions between Spo0A, Spo0E, and RstA constitute a previously unknown molecular switch that coordinates sporulation with motility and toxin production. Reinvestigation of Spo0E function in B. subtilis revealed that Spo0E induced motility, demonstrating Spo0E regulation of motility and sporulation among divergent species. Further, 3D structural analyses of Spo0E revealed specific and exclusive interactions between Spo0E and binding partners in C. difficile and B. subtilis that provide insight into the conservation of this regulatory mechanism among different species.