Interleukin-1 (IL-1) is a potent bone resorbing cytokine with diverse biological effects. We previously reported that IL-1 inhibits PDGF-AA-induced biological activities including PDGF-AA-induced tyrosyl phosphorylation. In the present studies, we first investigated and compared the tyrosyl phosphorylation pattern induced by EGF, IGF-1, PDGF-AA, and bFGF in human osteoblastic cells. We then examined the effect of IL-1 on the tyrosyl phosphoproteins induced by each ligand. Immunoblot analyses show that EGF, IGF-1, and PDGF-AA each elicit a different pattern of tyrosyl phosphorylated proteins in normal human osteoblastic cells. IL-1 beta inhibits PDGF-AA induced autophosphorylation by down-regulation of the PDGF-alpha receptor, as demonstrated by immunoprecipitation experiments. For other ligand-induced tyrosyl phosphoproteins, IL-1 beta reduced the intensity of EGF-induced pp55,000, and IGF-1 induced pp185,000 and pp175,000. These experiments indicate that IL-1 inhibits phosphorylation of specific proteins induced by growth factors. By using inhibitors of secondary message pathways, we determined that the inhibitory effect of IL-1 beta on PDGF-AA receptor binding and receptor tyrosyl autophosphorylation was not dependent on protein kinase A, protein kinase C, or the formation of prostaglandins. These data suggest the existence of an alternative pathway that may participate in IL-1 beta signaling.

The formation mechanism of press mura in 2-domain FFS-LCD is investigated. We analyze LC directors by comparing the brightness with rotated polarizer and 3D simulation. The relation of press mura and pixel edge designs is also discussed. Additionally, the press-mura phenomenon of negative LC is also reported.

Platelet-derived growth factor (PDGF) is thought to play a significant role in bone repair and regeneration. We previously demonstrated that PDGF-AA-induced chemotaxis and proliferation can be modulated by IL-1. We now report that IL-1 and transforming growth factor-beta (TGF-beta) significantly decrease the number of PDGF-AA binding sites in both normal and tumor-derived human osteoblastic cells, whereas PDGF-BB binding is minimally affected. The affinity of PDGF-AA binding remains unchanged in the presence of IL-1, but is slightly reduced by TGF-beta as demonstrated by Scatchard analysis. We also showed that tyrosyl kinase phosphorylation after PDGF-AA binding is decreased in the presence of both IL-1 and TGF-beta. Northern blot analysis indicates that both IL-1 and TGF-beta decrease the expression of PDGF-alpha receptor mRNA. These results suggest that IL-1 and TGF-beta have the potential to regulate PDGF-AA-induced biologic activity in normal human osteoblastic cells and in human osteoblastic sarcoma cells by decreasing the levels of the PDGF-alpha receptor.

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