Abstract
Purpose: :
We have previously reported that inflammatory cytokines are involved in the pathogeneses of retinal vascular diseases; hyalocytes in the vitreous tissue may also contribute to pathogeneses of these diseases (Acta Ophthalmol. 2009). In addition, hyaluronan (HA) is known to regulate endothelial cell function. To confirm the role of tumor necrosis factor-alpha (TNF-α) in pathogeneses of retinal vascular diseases, we investigated the effects of TNF-α on HA production and cell proliferation using porcine and human vitreous-derived cells.
Methods: :
A porcine vitreous-derived cell line (PH cells) and human vitreous derived-cell strain (HV cells), which had been previously established (Exp Eye Res. 2007, Acta Ophthalmol. 2009), were used in the present study. The expression of HA synthase (HAS) 1, 2, and 3 and hyaluronidase (HYAL) 1, 2, and 3 were detected in mRNA. HA production was confirmed at the protein level after stimulation with TNF-α and/or 4-Methylumbelliferone (4-MU). The viability of the PH and HV cells that were stimulated with TNF-α and/or 4-MU was determined using the MTT assay.
Results: :
In PH cells, the expression of HAS2 was stimulated by TNF-α at the mRNA level; HA production was also found to be induced. 4-MU inhibited HA production in PH cells stimulated with TNF-α. TNF-α did not affect the expression of HAS1, HAS3, HYAL1, HYAL2, or HYAL3 at the mRNA level, but was found to decrease the viability of PH cells. Furthermore, 4-MU decreased the viability of PH cells stimulated with TNF-α. In HV cells, neither HA production and regulation nor cell proliferation were induced by TNF-α.
Conclusions: :
HA production was regulated by TNF-α in PH cells. Therefore, HA, TNF-α, and hyalocytes may contribute to the pathogeneses of retinal vascular diseases. Differences in the responses of porcine and human vitreous-derived cells may be due to differences between these species. There may also be several kinds of cells in vitreous tissue. Further investigations on the functions of vitreous cells and the effects of TNF-α on these cells are required.
Keywords: cytokines/chemokines • apoptosis/cell death • vitreous