Inhibitory effect of long non-coding RNA Neat1 on ultraviolet B-induced pyroptosis of human lens epithelial cells and its mechanism

Authors: Wang Min,  Wang Yanxi,  Chen Ying,  Zhao Yueyue,  Yang Tao,  Kang Gangjin
DOI: 10.3760/cma.j.cn115989-20211214-00687
Published 2023-06-10
Cite as Chin J Exp Ophthalmol, 2023, 41(6): 536-544.

Abstract                              [Download PDF] [Read Full Text]

Objective

To investigate the role of long non-coding RNA nuclear paraspeckle assembly transcript 1 (Neat1) in pyroptosis of ultraviolet B (UVB)-induced human lens epithelial cells (LECs) and to explore the possible mechanism.

Methods

The human lens epithelial cell line HLE-B3 was cultured in vitro, and cells at log phase were exposed to ultraviolet B for 0, 2, 4 and 8 hours, respectively.The expression of cysteine aspartic acid-specific protease-1 (caspase-1), a protein related to pyroptosis, was detected by Western blot.The relative expression level of Neat1 in cells after different irradiation durations was determined by real-time quantitative PCR.Cell viability was determined by the cell counting kit-8 (CCK-8) method to screen the optimal irradiation duration for UVB-induced LECs pyroptosis, which was finally determined to be 4 hours.HLE-B3 cells were divided into negative siRNA transfection group, siRNA Neat1 transfection group, negative siRNA transfection+ irradiation group and siRNA Neat1 transfection+ irradiation group, and were transfected with corresponding reagents for 24 hours.The negative siRNA transfection+ irradiation group and siRNA Neat1 transfection+ irradiation group were irradiated with UVB for 4 hours after transfection.The cell viability was detected by the CCK-8 method.The pyroptosis rate was detected by flow cytometry.The expression levels of caspase-1, gasdermin D (GSDMD) and nod-like receptor protein 3 (NLRP3) proteins were detected by Western blot.The concentration of interleukin (IL)-1β was detected by enzyme-linked immunosorbent assay (ELISA). Ultrastructural changes in HLE-B3 cells were observed under a transmission electron microscope.

Results

The grayscale of caspase-1 protein bands increased with the extension of irradiation duration.The relative expression levels of caspase-1 protein at 0, 2, 4 and 8 hours of irradiation were 0.05±0.01, 0.25±0.07, 0.51±0.04 and 0.74±0.02, respectively, with a statistically significant overall difference (F=168.223, P<0.001), and significant differences were found in paired comparisons (all at P<0.05). With prolonged irradiation, the relative expression level of Neat1 mRNA increased and the cell viability decreased, with statistically significant differences in paired comparisons (all at P<0.05). Compared with negative siRNA transfection group, the cell viability was increased in siRNA Neat1 transfection group and decreased in negative siRNA transfection+ irradiation group, with statistically significant differences (both at P<0.01). Compared with negative siRNA transfection+ irradiation group, the cell viability was increased in siRNA Neat1 transfection+ irradiation group, showing a statistically significant difference (P<0.05). The pyroptosis rate was significantly lower in negative siRNA transfection group and siRNA Neat1 transfection+ irradiation group than in negative siRNA transfection+ irradiation group, and the differences were statistically significant (both at P<0.01). The relative expression levels of caspase-1, NLRP3 and GSDMD proteins in negative siRNA transfection+ irradiation group were higher than those in negative siRNA transfection group and siRNA Neat1 transfection+ irradiation group and the differences were statistically significant (all at P<0.01). The concentration of IL-1β was significantly higher in negative siRNA transfection+ irradiation group than in negative siRNA transfection group and siRNA Neat1 transfection+ irradiation group, and the differences were statistically significant (all at P<0.05). Cell swelling, formed cell membrane pores, vacuolated cells and fuzzy mitochondrial cristae were seen in negative siRNA transfection+ irradiation group and siRNA Neat1 transfection+ irradiation group by transmission electron microscopy.Compared with negative siRNA transfection+ irradiation group, slighter cell swelling, fewer cell membrane pores and lighter mitochondrial swelling were seen in siRNA Neat1 transfection+ irradiation group.

Conclusions

Neat1 is involved in human LECs pyroptosis induced by UVB through the classic pyroptosis pathway mediated by caspase-1.Knockdown of Neat1 can inhibit the pyroptosis of human LECs.

Key words:

Cataract; Lens, crystalline; Epithelial cells; Pyroptosis; Ultraviolet B; LncRNA Neat1

Contributor Information

Wang Min

Department of Ophthalmology, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China

Wang Yanxi

Department of Ophthalmology, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China

Chen Ying

Department of Ophthalmology, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China

Zhao Yueyue

Department of Ophthalmology, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China

Yang Tao

Department of Ophthalmology, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China

Kang Gangjin

Department of Ophthalmology, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China

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