Hydrogen peroxide decreases the survival rate of HeLa cells with stable knockdown of survival motor neuron protein

The mutations of survival motor neuron (SMN) gene result in spinal muscular atrophy (SMA), a common neurodegenerative disease. Some of the motor neurons undergoing cell death is the predominant characteristic in SMA pathology. However, the viability and sensitivity to stresses of other cell types also need to be determined. In this article, we established HeLa stable cell line with inducible SMN knockdown to study its viability and sensitivity to oxidative stress. SMN knockdown in the HeLa stable cell line was induced by doxycycline. The proliferative and survival rates of SMN knockdown cells with or without hydrogen peroxide (H2O2) treatment were determined. Our results showed that the proliferative rate of SMN knockdown cells decreased only slightly compared with that of the cells without doxycycline treatment. In contrast, after H2O2 reached certain concentrations, the survival rate of SMN knockdown cells decreased significantly. Our data indicate that SMN knockdown alone is not critical to cell viability. However, when SMN knockdown cells are under stress, such as oxidative stress, their survival rate may significantly decrease. Our results will be helpful to prevent the detrimental effect caused by the cell death of non-motor neurons under stress in SMA patients. In addition, the cell model we established can be used to study the mechanism and screen drugs to prevent the detrimental effects in cases of SMA disease.

摘要Survival of motor neuron (SMN)基因突變會導致神經退化疾病：脊髓肌肉萎縮症(SMA)。有些運動神經元細胞死亡是脊髓肌肉萎縮症的病理特徵。至於病患運動神經元以外其他類型細胞的存活率及對壓力的敏感度則尚待深入研究，本文中，我們在HeLa細胞中建立誘導性基因減弱SMN以研究這些細胞的存活率及對壓力的敏感度。以doxycycline誘導將HeLa細胞中的SMN基因減弱後，再以H2O2處理觀察細胞增殖及存活率。我們的結果顯示SMN基因減弱的HeLa細胞與未加入doxycycline的控制組相比，其細胞增殖率只輕微下降。相反的，細胞若經過H2O2處理，SMN基因減弱的HeLa細胞其細胞存活率則顯著下降。我們的結果認為SMN基因減弱並非細胞存活的關鍵因素，但是當細胞遭遇壓力如氧化壓力時，細胞存活率會顯著下降。我們的結果將有助於SMA病人避免壓力造成非運動神經元細胞的傷害。此外，我們所建立的細胞模式將有助於SMA疾病的機制研究及藥物篩選。