Shielding of the geomagnetic field reduces hydrogen peroxide production in human neuroblastoma cell and inhibits the activity of CuZn superoxide dismutase

Accumulative evidence has shown the adverse effects of a geomagnetic field shielded condition, so called a hypomagnetic field (HMF), on the metabolic processes and oxidative stress in animals and cells. However, the underlying mechanism remains unclear. In this study, we evaluate the role of HMF on the regulation of cellular reactive oxygen species (ROS) in human neuroblastoma SH-SY5Y cells. We found that HMF exposure led to ROS decrease, and that restoring the decrease by additional HO rescued the HMF-enhanced cell proliferation. The measurements on ROS related indexes, including total anti-oxidant capacity, HO and superoxide anion levels, and superoxide dismutase (SOD) activity and expression, indicated that the HMF reduced HO production and inhibited the activity of CuZn-SOD. Moreover, the HMF accelerated the denaturation of CuZn-SOD as well as enhanced aggregation of CuZn-SOD protein, in vitro. Our findings indicate that CuZn-SOD is able to response to the HMF stress and suggest it a mediator of the HMF effect.

Icariin protects SH-SY5Y cells from formaldehyde-induced injury through suppression of Tau phosphorylation / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the neuroprotective effects of icariin on formaldehyde (FA)-treated human neuroblastoma SH-SY5Y cells and the possible mechanisms involved.</p><p><b>METHODS</b>SH-SY5Y cells were divided into FA treatment group, FA treatment group with icariin, and the control group. Cell viability, apoptosis, and morphological changes were determined by cell counting kit-8 (CCK 8), flow cytometry, and confocal microscopy, respectively. The phosphorylation of Tau protein was examined by western blotting.</p><p><b>RESULTS</b>FA showed a half lethal dose (LD50) of 0.3 mmol/L in SH-SY5Y cells under the experimental conditions. Icariin (1-10 µmol/L) prevented FA-induced cell death in SH-SY5Y cells in a dose-dependent manner, with the optimal effect observed at 5 µmol/L. After FA treatment, the absorbance in FA group was 1.31±0.05, while in the group of icariin (5 µmol/L) was 1.63±0.05. Examination of cell morphology by confocal microscopy demonstrated that 5 µmol/L icariin significantly attenuated FA-induced cell injury (P <0.05). Additionally, Icariin inhibited FA-induced cell apoptosis in SH-SY5Y cells. Results from western blotting showed that icariin suppressed FA-induced phosphorylation at Thr 181 and Ser 396 of Tau protein, while having no effect on the expression of the total Tau protein level. Furthermore, FA activated Tau kinase glycogen synthase kinase 3 beta (GSK-3β) by enhancement of Y216 phosphorylation, but icariin reduced Y216 phosphorylation and increased Ser 9 phosphorylation.</p><p><b>CONCLUSION</b>Icariin protects SH-SY5Y cells from FA-induced injury poßsibly through the inhibition of GSK-3β-mediated Tau phosphorylation.</p>

Elimination of the geomagnetic field stimulates the proliferation of mouse neural progenitor and stem cells

Living organisms are exposed to the geomagnetic field (GMF) throughout their lifespan. Elimination of the GMF, resulting in a hypogeomagnetic field (HMF), leads to central nervous system dysfunction and abnormal development in animals. However, the cellular mechanisms underlying these effects have not been identified so far. Here, we show that exposure to an HMF (<200 nT), produced by a magnetic field shielding chamber, promotes the proliferation of neural progenitor/stem cells (NPCs/NSCs) from C57BL/6 mice. Following seven-day HMF-exposure, the primary neurospheres (NSs) were significantly larger in size, and twice more NPCs/NSCs were harvested from neonatal NSs, when compared to the GMF controls. The self-renewal capacity and multipotency of the NSs were maintained, as HMF-exposed NSs were positive for NSC markers (Nestin and Sox2), and could differentiate into neurons and astrocyte/glial cells and be passaged continuously. In addition, adult mice exposed to the HMF for one month were observed to have a greater number of proliferative cells in the subventricular zone. These findings indicate that continuous HMF-exposure increases the proliferation of NPCs/NSCs, in vitro and in vivo. HMF-disturbed NPCs/NSCs production probably affects brain development and function, which provides a novel clue for elucidating the cellular mechanisms of the bio-HMF response.

Reactive carbonyl compounds (RCCs) cause aggregation and dysfunction of fibrinogen

Fibrinogen is a key protein involved in coagulation and its deposition on blood vessel walls plays an important role in the pathology of atherosclerosis. Although the causes of fibrinogen (fibrin) deposition have been studied in depth, little is known about the relationship between fibrinogen deposition and reactive carbonyl compounds (RCCs), compounds which are produced and released into the blood and react with plasma protein especially under conditions of oxidative stress and inflammation. Here, we investigated the effect of glycolaldehyde on the activity and deposition of fibrinogen compared with the common RCCs acrolein, methylglyoxal, glyoxal and malondialdehyde. At the same concentration (1 mmol/L), glycolaldehyde and acrolein had a stronger suppressive effect on fibrinogen activation than the other three RCCs. Fibrinogen aggregated when it was respectively incubated with glycolaldehyde and the other RCCs, as demonstrated by SDS-PAGE, electron microscopy and intrinsic fluorescence intensity measurements. Staining with Congo Red showed that glycolaldehyde- and acrolein-fibrinogen distinctly formed amyloid-like aggregations. Furthermore, the five RCCs, particularly glycolaldehyde and acrolein, delayed human plasma coagulation. Only glycolaldehyde showed a markedly suppressive effect on fibrinogenesis, none did the other four RCCs when their physiological blood concentrations were employyed, respectively. Taken together, it is glycolaldehyde that suppresses fibrinogenesis and induces protein aggregation most effectively, suggesting a putative pathological process for fibrinogen (fibrin) deposition in the blood.