Vascular endothelial growth factor expression by hyalocytes and its regulation by glucocorticoid

Abstract

Hyalocytes may be involved in various vitreoretinal diseases by increasing HIF-1alpha protein stability and HIF-1alpha-DNA binding, and thus increasing VEGF production under pathological conditions. Dexamethasone seems to be capable of inhibiting hypoxic and TNF-alpha dependent VEGF production, presumably via its inhibitory effects on HIF-1alpha protein levels and its DNA-binding activity.

Role of tumour necrosis factor- (TNF ) in the functional properties of hyalocytes

“…Dexamethasone inhibits VEGF-A expression by hyalocytes 21. In this study, we observed that dexamethasone inhibited TNFα-induced proliferation of hyalocytes but not migration (figure 5).…”

“…Intravitreal injection of steroids is currently used in the management of intravitreal inflammation in various vitreoretinal diseases, including uveitis and diabetic retinopathy 19 20. Recently, we have shown that vascular epithelial growth factor (VEGF)-A expression by hyalocytes is inhibited by dexamethasone 21. However, the effects of dexamethasone on the functional properties of hyalocytes in inflammation-associated diseases have not been clarified.…”

Stratified control of IGF-I expression by hypoxia and stress hormones in osteoblasts

“…Furthermore, high HIF1α levels have often been associated with a decrease in the proliferation of some non-oncogenic cells (Goda et al, 2003; Zhu et al, 2005; DeBerardinis et al, 2008; Higgins et al, 2008; Millman et al, 2009), which is also consistent with our results in osteoblasts. By contrast, glucocorticoid reduced HIF activity, which has been seen in some but not all cell types (Kodama et al, 2003; Hata et al, 2008; Wagner et al, 2008; Gaber et al, 2011), and may depend in part on a physical complex that forms between hormone activated GR and HIF1α (Sun et al, 2010). Based on our current and previous studies, this may also result from an increase in endogenous C/EBP expression in glucocorticoid treated osteoblasts, inasmuch as over expression of C/EBPδ also suppressed HIF activity.…”

An Overview of Diabetes and Ocular Health

“…68,87 Previous studies have suggested that peribulbar steroid, with or without focal photocoagulation, is unlikely to be of substantial benefit in cases of diabetic macular edema with good visual acuity 88 (Figure 13.7A, B). However, the mechanism of the action is not fully understood.…”

“…60 Hyalocytes Hyalocytes have been described as occurring in the peripheral or cortical region of the vitreous close to the inner surface of the retina. 68 Hyalocytes are resident macrophages and originate from the blood monocytes 62,63 (Figure 13.4A).…”