Soybean agglutinin binding to corneal endothelial cell surfaces disrupts in situ monolayer integrity and actin organization and interferes with wound repair

Abstract

Rat corneal endothelium demonstrates cell-surface soybean agglutinin (SBA) binding during organ-culture or injury. When organ-cultured in medium containing SBA, the endothelial monolayer is disrupted because of cell-cell and cell-matrix alterations. SBA binding disorganizes the circumferential microfilament bundles (CMBs), an effect that is partially prevented by phallacidin preincubation. This disruption is reversible if tissues are returned to standard culture medium. Serum heightens SBA binding, whereas puromycin prevents it. Neither actinomycin D nor α-amanitin inhibits SBA binding, suggesting that SBA-binding protein(s) may be post-transcriptionally regulated. During injury-induced cell migration in the presence of SBA, cellular processes are blunted and fail to extend significantly outward. By 72 h post-injury, cells of SBA-treated tissues repopulate the wound but demonstrate little association with neighboring cells. Cells migrating in the presence of N-acetylgalactosamine appear normal but also fail to reassociate with other cells in the jury zone. Immunofluorescent staining for ZO-1 reveals punctuate patterns in cells of control tissues, whereas neither SBA- nor N-acetylgalactosamine-treated tissues exhibit ZO-1 staining. Terminal N-acetylgalactosamine removal fails to affect cell morphology, actin organization, or migration but prevents lectin binding. Our results suggest that SBA binding reflects the synthesis of a stress-induced protein(s) that may play a role in reestablishing cell-cell relationships during monolayer reorganization following injury.

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