Arctiin blocks hydrogen peroxide-induced senescence and cell death though microRNA expression changes in human dermal papilla cells

Background

Accumulating evidence indicates that reactive oxygen species (ROS) are an important etiological factor for the induction of dermal papilla cell senescence and hair loss, which is also known alopecia. Arctiin is an active lignin isolated from Arctium lappa and has anti-inflammation, anti-microbial, and anti-carcinogenic effects. In the present study, we found that arctiin exerts anti-oxidative effects on human hair dermal papilla cells (HHDPCs).

Results

To better understand the mechanism, we analyzed the level of hydrogen peroxide (H₂O₂)-induced cytotoxicity, cell death, ROS production and senescence after arctiin pretreatment of HHDPCs. The results showed that arctiin pretreatment significantly inhibited the H₂O₂-induced reduction in cell viability. Moreover, H₂O₂-induced sub-G1 phase accumulation and G2 cell cycle arrest were also downregulated by arctiin pretreatment. Interestingly, the increase in intracellular ROS mediated by H₂O₂ was drastically decreased in HHDPCs cultured in the presence of arctiin. This effect was confirmed by senescence associated-beta galactosidase (SA-β-gal) assay results; we found that arctiin pretreatment impaired H₂O₂-induced senescence in HHDPCs. Using microRNA (miRNA) microarray and bioinformatic analysis, we showed that this anti-oxidative effect of arctiin in HHDPCs was related with mitogen-activated protein kinase (MAPK) and Wnt signaling pathways.

Conclusions

Taken together, our data suggest that arctiin has a protective effect on ROS-induced cell dysfunction in HHDPCs and may therefore be useful for alopecia prevention and treatment strategies.     

髋关节置换治疗高龄不稳定型股骨粗隆间骨折的临床效果观察

目的：探讨髋关节置换手术治疗高龄人群不稳定型股骨粗隆间骨折的稳定性及愈后生活质量。方法：选取我院骨科收治的110 例不稳定型股骨粗隆间骨折患者作为研究对象,随机分为两组,观察组55 例采用人工全髋关节置换术,对照组55 例采用DHS内固定治疗,观察两组患者的手术时间、手术出血量、平均住院时间、临床疗效、术后并发症及愈后生存质量。结果：观察组手术时间及手术出血量大于对照组,但患者平均卧床时间及显著短于对照组（P＜0.05）。观察组手术总有效率为87.27%,对照组手术总有效率为70.90%,观察组手术效果明显优于对照组（P＜0.05）。观察组术后并发症发生率为7.27%,显著低于对照组（25.45%）（P ＜ 0.05）。观察组患者生活质量满意度为80.00 %,明显高于对照组（61.82%）（P ＜ 0.05）。结论：髋关节置换手术能减少术中出血量、患者下地活动时间早,局部组织修复速度快,对于体质较差、年龄大的老年患者,该术式是延长预期寿命的最佳手术方式。     

The guanidine like effects of arginine on aminoacylase and salt-induced molten globule state

Aminoacylase is a dimeric enzyme containing one Zn(2+) ion per subunit. The arginine (Arg)-induced unfolding of Holo-aminoacylase and Apo-aminoacylase has been studied by measurement of enzyme activity, fluorescence emission spectra and 1-anilino-8-naphthalenesulfonate (ANS) fluorescence spectra. Besides being the most alkaline amino acid, the arginine molecule contains a positively charged guanidine group, similar to guanidine hydrochloride, and has been used in many refolding systems to suppress protein aggregation. Our results showed that arginine caused the inactivation and unfolding of aminoacylase, with no aggregation during denaturation. A comparison between the unfolding of aminoacylase in aqueous and HCl (pH 7.5) arginine solutions indicated that the guanidine group of arginine had protein-denaturing effects similar to those of guanidine hydrochloride, which might help us understand the mechanism by which arginine suppresses incorrect refolding. The results showed that arginine-denatured aminoacylase could be reactivated and refolded correctly, indicating that arginine is as good a denaturant as the guanidine or urea for study of protein unfolding and refolding. Both the intrinsic fluorescence and the ANS fluorescence spectra showed that the arginine-unfolded aminoacylase formed a molten globule state in the presence of KCl, suggesting that intermediates exist during aminoacylase refolding. The results for the Apo-aminoacylase followed were similar to those for the Holo-enzyme, suggesting that Holo- and Apo-aminoacylase might have a similar unfolding and refolding pathway.