Annis, D. S. | bioRxiv Science

bioRxiv2022

Molecular anatomy of eosinophil activation by IL5 and IL33

IL5 and IL33 are major activating cytokines that cause circulating eosinophils to polarize, adhere, and release their granule contents. We correlated microscopic features of purified human blood eosinophils stimulated for 10 min with IL5 or IL33 with phosphoproteomic changes determined by multiplexed isobaric labeling. IL5 caused phosphorylation of sites implicated in JAK/STAT signaling and localization of pYSTAT3 to nuclear speckles whereas IL33 caused phosphorylation of sites implicated in NF{kappa}B signaling and localization of RELA to nuclear speckles. Phosphosites commonly impacted by IL5 and IL33 were involved in networks associated with cytoskeletal organization and eosinophil adhesion and migration. Many differentially regulated phosphosites were in a diverse set of large proteins--RAB44, a "large RAB" associated with crystalloid granules; NHSL2 and VIM that change localization along with the nucleus during polarization; TNFAIP3 vital for control of NF{kappa}B signaling, and SRRM2 and PML that localize, respectively, to nuclear speckles and PML bodies. Gene expression analysis demonstrated differential effects of IL5 and IL33 on IL18, CCL5, CSF1, and TNFSF14. Thus, common effects of IL5 and IL33 on the eosinophil phosphoproteome are important for positioning in tissues, degranulation, and initiation of new protein synthesis whereas specific effects on protein synthesis contribute to phenotypic heterogeneity. KEY POINTSIL33 and IL5 impact common pathways of eosinophil cytoskeletal reorganization, adhesion and migration. Each lobe of the human eosinophil nucleus has a specific anatomy poised for new onset of cytokine-specific transcription and splicing.

cell biology↗

bioRxiv2017

Adaptation Of Staphylococcus saprophyticus At The Host-Pathogen Interface

Human-pathogenic bacteria are found in a variety of niches, including free-living, zoonotic, and microbiome environments. Identifying bacterial adaptions that enable invasive disease is an important means of gaining insight into the molecular basis of pathogenesis and understanding pathogen emergence. Staphylococcus saprophyticus, a leading cause of urinary tract infections, can be found in the environment, food, animals, and the human microbiome. We identified a selective sweep in the gene encoding the Aas adhesin, a key virulence factor that binds host fibronectin. We hypothesize that the mutation under selection (aas_2206A>C) facilitates colonization of the urinary tract, an environment where bacteria are subject to strong shearing forces. The mutation appears to have enabled emergence and expansion of a human pathogenic lineage of S. saprophyticus. These results demonstrate the power of evolutionary genomic approaches in discovering the genetic basis of virulence and emphasize the pleiotropy and adaptability of bacteria occupying diverse niches.\n\nImportanceStaphylococcus saprophyticus is an important cause of urinary tract infections (UTI) in women, which are common, can be severe, and are associated with significant impacts to public health. In addition to being a cause of human UTI, S. saprophyticus can be found in the environment, in food, and associated with animals. After discovering that UTI strains of S. saprophyticus are for the most part closely related to each other, we sought to determine whether these strains are specially adapted to cause disease in humans. We found evidence suggesting that a mutation in the gene aas is advantageous in the context of human infection. We hypothesize that the mutation allows S. saprophyticus to survive better in the human urinary tract. These results show how bacteria found in the environment can evolve to cause disease.

microbiology↗