Hyaluronan synthase in trabecular meshwork cells.
OBJECTIVE
Hyaluronan is present in the trabecular meshwork where it is involved in the pathophysiology of aqueous outflow environment. In this study, the expression and regulation of hyaluronan synthase (HAS), which is the enzyme synthesising hyaluronan, in trabecular meshwork cells were investigated.


METHODS
Cultured bovine trabecular meshwork cells (BTMCs) were used. HAS expression in BTMCs was examined by RT-PCR. The effects of transforming growth factor beta (TGF-beta) and platelet derived growth factor BB (PDGF-BB) on HAS expression in BTMCs were examined by quantitative RT-PCR. The HAS2 expression by TGF-beta and PDGF-BB at the protein level was also confirmed immunohistochemically. The production of hyaluronan from BTMCs was detected by high performance liquid chromatography (HPLC).


RESULTS
Three HAS isoforms were expressed in BTMCs at the mRNA level. Among HAS isoforms, only the expression of HAS2 mRNA was increased by the administration of TGF-beta or PDGF-BB. HAS2 upregulation by these growth factors was also confirmed at the protein level. Further, hyaluronan production from BTMCs was stimulated by TGF-beta or PDGF-BB.


CONCLUSIONS
Expression of HAS in trabecular meshwork may maintain the hyaluronan content in the aqueous outflow pathway. Its production is regulated by TGF-beta and PDGF-BB. The regulation of the expression of HAS in trabecular meshwork might be useful for modulating the aqueous outflow environment.
Usui
T
T
Department of Ophthalmology, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
Nakajima
F
F
Ideta
R
R
Kaji
Y
Y
Suzuki
Y
Y
Araie
M
M
Miyauchi
S
S
Heldin
P
P
Yamashita
H
H
D000818:Animals; D000077214:Becaplermin; D002417:Cattle; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D005786:Gene Expression Regulation; D014453:Glucuronosyltransferase / Q000032:analysis*; D016695:Glycosyltransferases; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000096:biosynthesis; D007150:Immunohistochemistry / Q000379:methods; D007527:Isoenzymes / Q000032:analysis; D008565:Membrane Proteins; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014129:Trabecular Meshwork / Q000187:drug effects / Q000201:enzymology*; D014166:Transferases; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D015854:Up-Regulation; D029867:Xenopus Proteins
D007527:Isoenzymes; D008565:Membrane Proteins; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D029867:Xenopus Proteins; D000077214:Becaplermin; D006820:Hyaluronic Acid; D014166:Transferases; D016695:Glycosyltransferases; D014453:Glucuronosyltransferase; C056944:HAS1 protein, Xenopus; C491096:Has2 protein, Xenopus; D000076002:Hyaluronan Synthases