Osmolyte taurine induction in UVA exposed human retinal pigment epithelial cells.

AIM: To explore the osmolytes expression in ultraviolet (UVA) stressed human retinal pigment epithelial cells. METHODS: Osmolyte transporters and vascular endothelial growth factor (VEGF) messenger RNA (mRNA) were determined by real time polymerase chain reaction (PCR). Osmolyte uptake was measured by radioimmunoassay. VEGF concentrations were determined by immunoassay and enzyme-linked immunosorbent assay (ELISA). Osmolyte taurine transporter (TAUT) were silenced by siRNA technology. RESULTS: Hypertonicity accelerated osmolyte betaine uptake, myoinositol uptake, and taurine uptake, compared to normotonic stress. UVA irradiation also accelerated osmolyte transporters expression and osmolytes uptake. Especially, osmolyte taurine remarkably inhibited VEGF release induced by UVA irradiation. VEGF in the UVA stressed retinal pigment epithelial cell supernatant was accumulated slow after taurine preincubation. VEGF expression increased significantly in UVA-stressed cells after TAUT silencing. Moreover, taurine reduced the VEGF level in human ocular aqueous humor. CONCLUSION: The inhibition of VEGF by osmolyte taurine plays the crucial role in retina adaption to UVA irradiation.

Taurine reduces blue light-induced retinal neuronal cell apoptosis in vitro.

BACKGROUND: The massive uptake of organic compatible osmolytes is a self-protective response to multiple stressors. OBJECTIVE: This study aimed to determine the protective effects of the osmolyte taurine against blue light-induced apoptosis in retinal neuronal cells in vitro. METHODS: Real-time PCR was used to measure osmolyte transport. Radioimmunoassays were performed to measure osmolyte uptake. Cell Counting Kit-8 assays were conducted to measure cellular viability. Flow cytometry analysis was used to measure apoptosis. RESULTS: Compared with normotonic stress, hypertonic stress-induced uptake of osmolytes, including betaine, myoinositol, and taurine, into the retinal neuronal cells. Blue light increased osmolyte transporter mRNA expression together with osmolyte uptake. Furthermore, taurine significantly suppressed blue light-induced retinal neuronal cell apoptosis. CONCLUSION: The compatible osmolyte taurine may have an important role in cell resistance to blue light and cell survival.

Taurine prevents ultraviolet B induced apoptosis in retinal ganglion cells.

BACKGROUND: Compatible osmolytes accumulation is an active resistance response in retina under ultraviolet (UV) radiation and hypertonicity conditions. OBJECTIVE: The purpose of this research is to investigate the protective role of taurine on retina under UVB radiation. METHODS: Osmolytes transporters were measured by quantitative realtime PCR. Osmolytes uptake was estimated by radioimmunoassay. Cell viability was calculated by MTT assay. Cell apoptosis was measured by flow cytometry analysis. RESULTS: Hypertonicity accelerated osmolytes uptake into retinal ganglion cells (RGCs) including taurine, betadine, and myoinositol. UVB radiation increased osmolytes transporter expression and osmolytes uptake. In addition, osmolyte taurine remarkably prevented UVB radiation induced cell apoptosis in RGCs. CONCLUSIONS: The effect of compatible osmolyte taurine on cell survival rate may play an important role in cell resistance and adaption to UVB exposure.

Taurine Protects Lens Epithelial Cells Against Ultraviolet B-Induced Apoptosis.

BACKGROUND: The massive uptake of compatible osmolytes is a self-protective response shared by lens exposed to hypertonic stress and ultraviolet stress. OBJECTIVE: This study aimed to investigate the protective effects of taurine against ultraviolet B-induced cytotoxicity in the lens epithelial cells. METHODS: Real-time PCR was used to measure osmolytes transport. Radioimmunoassay was used to measure osmolytes uptake. Cell counting kit-8 assays were used to measure cellular viability. Flow cytometry analysis was used to measure apoptosis level. RESULTS: Compared with normotonic stress, hypertonic stress-induced osmolytes uptake into the lens epithelial cells such as betaine, myoinositol and taurine. UVB exposure increased osmolytes transporter mRNA expression together with osmolytes uptake. Moreover, taurine suppressed UVB-induced cell apoptosis in the lens epithelial cells significantly. CONCLUSIONS: The effect of compatible osmolyte taurine on cell survival rate may play an important role in cell resistance and adaption to UVB exposure.

Taurine inhibits interleukin-6 expression and release induced by ultraviolet B exposure to human retinal pigment epithelium cells.

BACKGROUND: The massive uptake of compatible osmolytes is a self-protective response shared by retina exposed to hypertonic stress and ultraviolet stress. OBJECTIVE: This study aimed to investigate the protective effects of taurine against ultraviolet damage in human retinal pigment epithelium cells. METHODS: Real-time PCR, radioimmunoassay, ELISA and immunoassay were used to measure osmolyte uptake and IL-6 expression. RESULTS: Compared with normotonic stress, hypertonic stress led to an induction of osmolyte uptake including betaine, myoinositol and taurine. UVB exposure upregulated osmolyte transporter mRNA expression and increased osmolyte uptake respectively. Especially, taurine suppressed UVB-induced IL-6 mRNA expression significantly. The accumulation of IL-6 in UVB-exposed human retinal pigment epithelial cells supernatant was much slower when the cells were preincubated with taurine. Moreover, taurine suppressed IL-6 concentration in aqueous humour. CONCLUSION: The effect of compatible osmolyte taurine on IL-6 expression and release may play an important role in cell resistance and adaption to UVB exposure.