Production and secretion of transforming growth factor beta (TGF-beta) by the human lacrimal gland.
OBJECTIVE
Transforming growth factor beta (TGF-beta) isoforms 1 and 2 have recently been detected in stimulated human tear fluid. The purpose of this study was to determine if these TGF-sbeta are produced and secreted by the lacrimal gland.


METHODS
To accomplish this, reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect expression of TGF-beta1 and TGF-beta2 mRNAs in normal human and rabbit lacrimal gland biopsies. Northern blot analyses were used for comparing the relative levels of expression of these TGF-beta mRNAs in rabbit lacrimal glands. Human lacrimal gland biopsies were evaluated by immunohistochemistry for production of TGF-beta1, TGF-beta1 latency associated peptide (LAP), and TGF-beta2 proteins. Supernatants of unstimulated and carbachol-stimulated human lacrimal gland explant cultures were evaluated for secretion of TGF-beta1 and TGF-beta2 by ELISA:


RESULTS
TGF-beta1 and TGF-beta2 mRNA expression was found in all human and rabbit lacrimal gland specimens by RT-PCR. A greater level of expression of TGF-beta1 than TGF-beta2 mRNA in the rabbit lacrimal gland was noted by Northern blot. In human lacrimal gland biopsies, TGF-beta1 and TGF-beta1 LAP were detected in acinar and ductal epithelia by immunohistochemistry. TGF-beta2 specific antibodies stained a small percentage of acinar and ductal epithelia, as well as material within the lumens of tubulo-acinar complexes in one-third of these glands. TGF-beta1 was detected in supernatants of human lacrimal gland explants, and the concentration of TGF-beta1 increased by an average of 280% after carbachol-stimulation (p = 0.004). TGF-beta2 could not be detected in unstimulated or stimulated human lacrimal gland supernatants.


CONCLUSIONS
The results of these experiments indicate that TGF-beta1 and TGF-beta2 are produced by and TGF-beta1 is secreted by the human lacrimal gland. They also suggest that the lacrimal gland may be one source of TGF-beta in human tear fluid.
Yoshino
K
K
Ocular Surface and Tear Center, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami School of Medicine, Miami, FL 33136, USA.
Garg
R
R
Monroy
D
D
Ji
Z
Z
Pflugfelder
S C
SC
D000293:Adolescent; D000328:Adult; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002217:Carbachol / Q000494:pharmacology; D018678:Cholinergic Agents / Q000494:pharmacology; D017931:DNA Primers / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007765:Lacrimal Apparatus / Q000033:anatomy & histology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010446:Peptide Fragments; D016133:Polymerase Chain Reaction; D011498:Protein Precursors; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D016212:Transforming Growth Factor beta / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D053773:Transforming Growth Factor beta1
D018678:Cholinergic Agents; D017931:DNA Primers; D010446:Peptide Fragments; D011498:Protein Precursors; D011506:Proteins; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D002217:Carbachol