[TFF peptides. New mucus-associated secretory products of the conjunctiva]

The molecular architecture of the human ocular mucus is not yet completely understood. Recently, TFF peptides (formerly known as trefoil factors or P-domain peptides) could be identified as new constituents of this delicate mucus. Members of the TFF-peptide family are typical secretory products of mucous epithelia and three are known in humans and designated as TFF1, TFF2 and TFF3. They enhance cell migratory processes (motogenic effect), they show anti-apoptotic effects and are inflammatory modulators Both TFF1 and TFF3 expression could be monitored by the reverse transcription-polymerase chain reaction (RT-PCR) in the human conjunctiva; in contrast, TFF2 transcripts were not detectable. Using immunohistochemistry, TFF1 and TFF3 peptides were found in varying concentrations solely in secretory vesicles of conjunctival goblet cells. This localisation matches precisely that of the secretory mucin MUC5AC. Thus, conjunctival TFF1 and TFF3 have to be considered as typical mucin-associated peptides probably modulating the rheological properties of the ocular mucus and the tear fluid. Future investigations are in progress to elucidate the role of TFF-peptides during pathological conditions of the eye as well as their diagnostic and therapeutic potential.