Androgen exposure impairs neutrophil maturation and function within the infected kidney

Abstract

Urinary tract infections (UTIs) in men are uncommon but carry increased risk for severe pyelonephritis and other complications. In models of Escherichia coli UTI, male C3H/HeN mice uniformly develop high-titer pyelonephritis (most with renal abscesses) in a testosterone-dependent manner, but the mechanisms underlying this phenotype are unknown. Here, using female mouse models, we show that androgen exposure impairs neutrophil maturation in the upper and lower urinary tract, compounded by an additional reduction of neutrophil function specifically within the infected kidney, enabling persistent high-titer infection and promoting abscess formation. Following intravesical inoculation with uropathogenic E. coli (UPEC), kidneys of androgen-exposed C3H mice showed delayed local pro-inflammatory cytokine responses while robustly recruiting neutrophils. These were enriched for an end-organ-specific population of aged but immature neutrophils (CD49d+, CD101-). Compared to their mature counterparts, these aged immature kidney neutrophils exhibited reduced functions in vitro, including impaired degranulation and diminished phagocytic activity, while splenic, bone marrow, and bladder neutrophils did not display these alterations. Further, aged immature neutrophils exhibited little phagocytic activity within intratubular UPEC communities in vivo. Experiments with B6 conditional androgen receptor (AR)-deficient mice indicated rescue of the maturation defect when AR was deleted in myeloid cells. We conclude that the recognized enhancement of UTI severity by androgens reflects urinary tract-specific impairment of neutrophil maturation (largely via cell-intrinsic AR signaling) and kidney-specific reduction in neutrophil antimicrobial capacity, resulting in failure to control renal bacterial infection.