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Downregulation of SMP30 in senescent human lens epithelial cells
Shuning Li1, Xi Chen1, Weixia Lai1
1Department of Ophthalmology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China.
Abstract:
Senescence marker protein 30 (SMP30) has been reported to serve antiapoptotic and antioxidant roles, as well as roles in Ca2+ regulation, and may be involved in the occurrence and development of cataract. The present study aimed to investigate the expression of SMP30 in senescent human lens epithelial cells (HLECs) and explored the relationship between SMP30 and aging. SRA01/04 cells, a HLEC line, were treated with H2O2 to mimic aging, and cell morphological changes were observed by microscopy and cell activity was exami-ned by MTT assay, senescence‑associated‑β‑galactosidase (SA‑β‑Gal) staining and cell cycle analysis. The expression of SMP30 mRNA and protein was measured by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blotting. Following prolonged low‑dose H2O2 exposure, cells exhibited senescence‑related morphological changes, reduced growth activity, increased SA‑β‑Gal positive staining and cell cycle arrest in the S and G2/M phases. SMP30 mRNA expression levels were significantly downregulated following exposure to 75 and 100 µM H2O2, and the protein expression levels in the same groups were decreased by >6‑fold compared with the control untreated cells. However, no significant change was observed in SMP30 expression in the 25 and 50 µM H2O2 exposure groups. These results suggest that, in the early stage of senescence induced by H2O2‑mediated chronic oxidative stress, there may be no significant change in SMP30 expression, but when the oxidative stress increases and senescence is aggravated, SMP30 may be significantly downregulated in the senescent HLECs. The present study indicates that SMP30 may be an important factor involved in the aging process of HLECs and the development of cataract.
Insights
Senescence marker protein 30 (SMP30) expression decreases in aged human lens epithelial cells (HLECs) due to oxidative stress, suggesting its role in cataract development.
Area of Science:
- Ophthalmology
- Cell Biology
- Aging Research
Background:
- Senescence marker protein 30 (SMP30) has known roles in apoptosis, oxidative stress, and calcium regulation.
- SMP30's involvement in cataract development, a common aging-related eye condition, is suggested but not fully understood.
Purpose of the Study:
- To investigate SMP30 expression in senescent human lens epithelial cells (HLECs).
- To explore the relationship between SMP30 and cellular aging, particularly in the context of oxidative stress.
Main Methods:
- Human lens epithelial cells (SRA01/04) were exposed to hydrogen peroxide (H2O2) to induce senescence.
- Cellular senescence was assessed via morphological changes, MTT assay, SA-β-Gal staining, and cell cycle analysis.
- SMP30 mRNA and protein levels were quantified using RT-qPCR and western blotting.
Main Results:
- H2O2 exposure induced senescence-related changes, including reduced cell activity and cell cycle arrest.
- Significant downregulation of SMP30 mRNA and protein was observed at higher H2O2 concentrations (75 and 100 µM).
- No significant change in SMP30 expression was noted at lower H2O2 concentrations (25 and 50 µM).
Conclusions:
- SMP30 expression is significantly reduced in HLECs under severe oxidative stress and advanced senescence.
- SMP30 downregulation may be a key factor in the aging of HLECs and the pathogenesis of cataract.
- The study highlights SMP30's potential as a biomarker and therapeutic target in age-related eye diseases.