PubMed · 12297219
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Luc A Cynober. 2002. Goodbye sodium alpha-ketoglutarate?. https://doi.org/10.1016/s0899-9007(02)00901-2
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Syndecan-1 is a heparan sulfate proteoglycan expressed on epithelia, and its ectodomain can be shed into the extracellular milieu, affecting a variety of cellular functions. Using two bacteria known to react with heparan sulfate, Listeria monocytogenes and Staphylococcus aureus, experiments were designed to clarify the effect of syndecan-1 shedding on bacterial internalization by human HT-29 enterocytes. Mature enterocytes were incubated with tumor necrosis factor (TNF)-alpha and/or interferon (IFN)-gamma for 16h prior to addition of bacteria. These cytokines acted synergistically to decrease syndecan-1 expression, assessed by visual observations of syndecan-1 expression on enterocytes using immunohistochemistry and a monoclonal antibody to the syndecan-1 core protein, by quantifying this fluorescent intensity, and by quantifying the concentration of shed syndecan-1 using an enzyme-linked immunoabsorbent assay. Neither IFN-gamma nor TNF-alpha alone had a noticeable effect on L. monocytogenes internalization, but a mixture of both cytokines resulted in decreased (P<0.01) internalization. Enterocyte preincubation with TNF-alpha alone, and with both cytokines, was associated with decreased S. aureus internalization, at P<0.05 and P<0.01, respectively. Thus, TNF-alpha and IFN-gamma acted synergistically to shed syndecan-1 ectodomains from HT-29 enterocytes, and shedding was associated with decreased internalization of two pathogenic bacteria, suggesting that syndecan-1 shedding may modulate the pathogenesis of specific microbes.
Replacement of donor lymphoid tissue by lymphocytes of recipient origin is an established phenomenon in small bowel transplants. However, replacement of donor epithelial cells of bowel grafts by host cells has not been demonstrated. The objective of our study was to determine whether donor enterocytes are replaced by host-derived enterocytes in the intestinal allograft. Graft biopsy specimens, obtained from five human male recipients of female intestine, were examined for the presence of male enterocytes. The biopsies dated from 90 to 770 days posttransplant. Formalin-fixed 3-microm specimen sections were stained for X and Y chromosomes by fluorescent in situ hybridization technique. Fluorescent microscopy of the stained sections identified male enterocytes in four patients, with a percentage of male cells ranging from 0.09% to 0.26% of the total enterocyte mass. Using the fluorescent in situ hybridization technique, we demonstrated the presence of host-derived male (XY) enterocytes in the female intestinal graft.
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