Protective effect of histatin 1 against ultraviolet‑induced damage to human corneal epithelial cells

Abstract

The aim of the present study was to investigate the role of histatin 1 (Hst1) in human corneal epithelial cells (HCECs) exposed to ultraviolet (UV) radiation. Prior to UV irradiation for various durations, HCECs were pre-treated with different concentrations of Hst1 and the effect on cell apoptosis and cell viability were examined by flow cytometry, alamarBlue® and MTT assays to determine the optimal concentration of Hst1 and UV dose. Cells were then subjected to quantitative PCR, ELISA and western blot analysis to determine the expression of cell damage-associated genes. HCECs exposed to UV light for 1 h displayed decreased viability when compared to that of control cells, and a 3 h UV exposure markedly increased the apoptotic rate of HECEs, while apoptosis was inhibited by pre-treatment with Hst1. UV radiation downregulated expression of insulin-like growth factor (IGF)-1 and B-cell lymphoma 2 (Bcl-2), while it upregulated Bcl-2-associated X protein (Bax) expression. Hst1 protected HCECs against UV-induced damage by upregulating the expression of IGF-1 protein and increasing the Bcl-2/Bax ratio. In conclusion, Hst1 may prevent UV-induced damage to corneal epithelial tissue injury and promote its healing.

Salivary Histatin 1 and 2 Are Targeted to Mitochondria and Endoplasmic Reticulum in Human Cells

“…From the above described results it may be deducted that the absence of amino sequences 1-11 in Hst2 and 23-38 in Hst5 (compared to Hst1) dramatically compromised their uptake rates. Consequently, we assessed the uptake dynamics and subcellular targets of truncated variants, F-Hst1 1-11 , F-Hst1 [12][13][14][15][16][17][18][19][20][21][22] and F-Hst1 [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] to explore their role in the cellular uptake of Hst1, Hst2 and Hst5. CLSM images revealed that the uptake of the truncated variants F-Hst1 1-11 , F-Hst1 12-22 and F-Hst1 [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] was much lower than that of the whole molecule F-Hst1 ( Figure 7A-D).…”

“…At 60 min post-incubation Hst1 showed a mean fluorescence of 2.00 ± 0.15 × 10 6 AFU, which was significantly higher than that of F-Hst1 12-22 (0.25 ± 0.03 × 10 6 AFU), F-Hst1 1-11 (0.07 ± 0.00 × 10 6 AFU) and F-Hst1 23-38 (0.07 ± 0.00 × 10 6 AFU) ( Figure 7F). F-Hst1 [12][13][14][15][16][17][18][19][20][21][22] mainly co-localized with the lysosomal marker (P coloc value of 0.55 ± 0.12, not with markers for the mitochondria or the ER or Golgi (Figure 8). Figure 7.…”

“…(A-D) CLSM images showed that a significantly higher amount of F-Hst1 accumulated in the vicinity of nuclei than F-Hst1 12-22 , while F-Hst1 1-11 and F-Hst1 [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] showed only mild accumulation. (E,F) Flow cytometric analysis confirmed that F-Hst1 showed the highest cell-associated fluorescence density, which was followed by F-Hst1 [12][13][14][15][16][17][18][19][20][21][22] . In contrast, F-Hst1 1-11 and F-Hst1 23-38 showed only mild fluorescence density.…”

“…Data were presented as mean ± SD. [12][13][14][15][16][17][18][19][20][21][22] was not targeted to mitochondria and endoplasmic reticulum (ER) in HO1N1 epithelial cells. (A-D) CLSM images showed that F-Hst1 12-22 showed co-localization with lysosomes (in blue) but not with mitochondria (in green) and ER (in blue) or Golgi (in green).…”

“…Comparable cell activating effects for Hst1 and Hst2 have also been found on endothelial cells, fibroblasts and osteogenic cells [5,12]. Hst1 also stimulates cell metabolic activity [13] and maintains cell viability under various adverse conditions, such as the presence of zoledronic acid [14] or ultraviolet radiation [15]. Interestingly, Hst1 and Hst2 are internalized in epithelial cells [2,7] in contrast to the D-enantiomer of Hst2 (D-Hst2), which can not promote the migration of epithelial cells and neither is internalized by the cells [3].…”