Caveolae-mediated entry of Salmonella typhimurium in a human M-cell model.
Intestinal M cells in Peyer's patches, the specialized antigen-sampling cells of the mucosal immune system, are exploited by Salmonella and other pathogens as a route of invasion. Thus, M cells have attracted lots of attention as a major target of the mucosal immune system. Here, we report that caveolin-1 plays a crucial role in the entry of Salmonella into M cells. We established an in vitro M-like cell model in which polarized enterocyte-like Caco-2 cells created after co-culturing with the Raji B cell line that underwent a phenotypic switch to a form that morphologically and functionally resembles the specialized antigen-transporting M cells. Caveolin-1 was highly expressed in the M-like cells, while not in Caco-2 cells, and a great number of Salmonella infected caveolin-1-expressing M-like cells. To elucidate the role of caveolin-1 in the entry of Salmonella, we downregulated caveolin-1 expression by siRNA and analyzed the level of Salmonella transcytosis across the M-like cells. Transcytosis of Salmonella was markedly reduced by downregulation of caveolin-1 in the M-like cells. These results suggest that caveolin-1 is implicated in the gateway of microbial pathogens through M cells, and, thus, provides a new target of mucosal immunity.
Lim
Jae Sung
JS
Department of Biochemistry, Chonnam National University Medical School, 5 Hakdong, Dongku, Gwangju 501-190, Republic of Korea.
Na
Hee Sam
HS
Lee
Hyun Chul
HC
Choy
Hyon E
HE
Park
Sang Chul
SC
Han
Jung Min
JM
Cho
Kyung A
KA
D021941:Caveolae / Q000378:metabolism / Q000382:microbiology*; D051242:Caveolin 1 / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology; D010581:Peyer's Patches / Q000378:metabolism / Q000382:microbiology*; D012480:Salmonella Infections / Q000378:metabolism / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000502:physiology*
D051242:Caveolin 1