title: Environmental cues and symbiont microbe-associated molecular patterns function in concert to drive the daily remodelling of the crypt-cell brush border of the Euprymna scolopes light organ.
abstract: Recent research has shown that the microbiota affects the biology of associated host epithelial tissues, including their circadian rhythms, although few data are available on how such influences shape the microarchitecture of the brush border. The squid-vibrio system exhibits two modifications of the brush border that supports the symbionts: effacement and repolarization. Together these occur on a daily rhythm in adult animals, at the dawn expulsion of symbionts into the environment, and symbiont colonization of the juvenile host induces an increase in microvillar density. Here we sought to define how these processes are related and the roles of both symbiont colonization and environmental cues. Ultrastructural analyses showed that the juvenile-organ brush borders also efface concomitantly with daily dawn-cued expulsion of symbionts. Manipulation of the environmental light cue and juvenile symbiotic state demonstrated that this behaviour requires the light cue, but not colonization. In contrast, symbionts were required for the observed increase in microvillar density that accompanies post dawn brush-border repolarization; this increase was induced solely by host exposure to phosphorylated lipid A of symbiont cells. These data demonstrate that a partnering of environmental and symbiont cues shapes the brush border and that microbe-associated molecular patterns play a role in the regulation of brush-border microarchitecture.
authors.affiliation: Department of Medical Microbiology and Immunology, University of Wisconsin - Madison, Madison, WI, 53706, USA.
authors.forename: Elizabeth A C
authors.initials: EA
authors.lastname: Heath-Heckman
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, Space Life Science Laboratory, Merritt Island, FL, 32953, USA.
authors.forename: Jamie
authors.initials: J
authors.lastname: Foster
authors.affiliation: Department of Microbiology, University of Iowa, Iowa City, IA, 52246, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Apicella
authors.affiliation: Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC, 27599, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Goldman
authors.affiliation: Department of Medical Microbiology and Immunology, University of Wisconsin - Madison, Madison, WI, 53706, USA. mcfallng@hawaii.edu.|PBRC, Kewalo Marine Laboratory, University of Hawaii, 41 Ahui Street, Honolulu, HI, 96813, USA. mcfallng@hawaii.edu.
authors.forename: Margaret
authors.initials: M
authors.lastname: McFall-Ngai
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D049832:Decapodiformes / Q000166:cytology / Q000382:microbiology / Q000502:physiology*; D004847:Epithelial Cells / Q000382:microbiology / Q000648:ultrastructure; D008027:Light; D008871:Microvilli / Q000382:microbiology* / Q000648:ultrastructure; D012679:Sense Organs / Q000166:cytology / Q000382:microbiology; D013559:Symbiosis / Q000528:radiation effects; D014733:Vibrio / Q000502:physiology*