Wei-chuan Mo

Misexpression of miR-196a induces eye anomaly in Xenopus laevis

miR-196a is located in the posterior trunk and plays a role in limb development. Here we show that miR-196a is able to induce eye anomaly in Xenopus laevis. Microinjection of synthetic miRNA precursor molecule for mammalian miR-196a into Xenopus embryo is sufficient for miR-196a overexpression during early development. The misexpression of miR-196a in anterior embryo led to dose-dependent eye anomalies, especially size reduction. In addition, the expression of ET, Rx1, Six3, Pax6, Lhx2, Optx2 and Ath5 in eye field or optic cup was also down-regulated. These results indicate that miR-196a can target gene(s) in the genetic network involved in eye formation, providing a potential tool for studying the mechanisms of eye development and diseases.

Magnetic shielding accelerates the proliferation of human neuroblastoma cell by promoting G1-phase progression.

Organisms have been exposed to the geomagnetic field (GMF) throughout evolutionary history. Exposure to the hypomagnetic field (HMF) by deep magnetic shielding has recently been suggested to have a negative effect on the structure and function of the central nervous system, particularly during early development. Although changes in cell growth and differentiation have been observed in the HMF, the effects of the HMF on cell cycle progression still remain unclear. Here we show that continuous HMF exposure significantly increases the proliferation of human neuroblastoma (SH-SY5Y) cells. The acceleration of proliferation results from a forward shift of the cell cycle in G1-phase. The G2/M-phase progression is not affected in the HMF. Our data is the first to demonstrate that the HMF can stimulate the proliferation of SH-SY5Y cells by promoting cell cycle progression in the G1-phase. This provides a novel way to study the mechanism of cells in response to changes of environmental magnetic field including the GMF.

Altered development of Xenopus embryos in a hypogeomagnetic field

The hypogeomagnetic field (HGMF; magnetic fields <200 nT) is one of the fundamental environmental factors of space. However, the effect of HGMF exposure on living systems remains unclear. In this article, we examine the biological effects of HGMF on the embryonic development of Xenopus laevis (African clawed frog). A decrease in horizontal third cleavage furrows and abnormal morphogenesis were observed in Xenopus embryos growing in the HGMF. HGMF exposure at the two-cell stage, but no later than the four-cell stage, is enough to alter the third cleavage geometry pattern. Immunofluorescent staining for α-tubulin showed reorientation of the spindle of four-cell stage blastomeres. These results indicate that a brief (2-h) exposure to HGMF is sufficient to interfere with the development of Xenopus embryos at cleavage stages. Also, the mitotic spindle could be an early sensor to the deprivation of the geomagnetic field, which provides a clue to the molecular mechanism underlying the morphological and other changes observed in the developing and/or developed embryos.

The protective effect of geniposide on human neuroblastoma cells in the presence of formaldehyde

BackgroundFormaldehyde can induce misfolding and aggregation of Tau protein and β amyloid protein, which are characteristic pathological features of Alzheimer’s disease (AD). An increase in endogenous formaldehyde concentration in the brain is closely related to dementia in aging people. Therefore, the discovery of effective drugs to counteract the adverse impact of formaldehyde on neuronal cells is beneficial for the development of appropriate treatments for age-associated cognitive decline.MethodsIn this study, we assessed the neuroprotective properties of TongLuoJiuNao (TLJN), a traditional Chinese medicine preparation, against formaldehyde stress in human neuroblastoma cells (SH-SY5Y cell line). The effect of TLJN and its main ingredients (geniposide and ginsenoside Rg1) on cell viability, apoptosis, intracellular antioxidant activity and the expression of apoptotic-related genes in the presence of formaldehyde were monitored.ResultsCell counting studies showed that in the presence of TLJN, the viability of formaldehyde-treated SH-SY5Y cells significantly recovered. Laser scanning confocal microscopy revealed that the morphology of formaldehyde-injured cells was rescued by TLJN and geniposide, an effective ingredient of TLJN. Moreover, the inhibitory effect of geniposide on formaldehyde-induced apoptosis was dose-dependent. The activity of intracellular antioxidants (superoxide dismutase and glutathione peroxidase) increased, as did mRNA and protein levels of the antiapoptotic gene Bcl-2 after the addition of geniposide. In contrast, the expression of the apoptotic-related gene - P53, apoptotic executer - caspase 3 and apoptotic initiator - caspase 9 were downregulated after geniposide treatment.ConclusionsOur results indicate that geniposide can protect SH-SY5Y cells against formaldehyde stress through modulating the expression of Bcl-2, P53, caspase 3 and caspase 9, and by increasing the activity of intracellular superoxide dismutase and glutathione peroxidase.

Transcriptome profile of human neuroblastoma cells in the hypomagnetic field

Research has shown that the hypomagnetic field (HMF) can affect embryo development, cell proliferation, learning and memory, and in vitro tubulin assembly. In the present study, we aimed to elucidate the molecular mechanism by which the HMF exerts its effect, by comparing the transcriptome profiles of human neuroblastoma cells exposed to either the HMF or the geomagnetic field. A total of 2464 differentially expressed genes (DEGs) were identified, 216 of which were up-regulated and 2248 of which were down-regulated after exposure to the HMF. These DEGs were found to be significantly clustered into several key processes, namely macromolecule localization, protein transport, RNA processing, and brain function. Seventeen DEGs were verified by real-time quantitative PCR, and the expression levels of nine of these DEGs were measured every 6 h. Most notably, MAPK1 and CRY2, showed significant up- and down-regulation, respectively, during the first 6 h of HMF exposure, which suggests involvement of the MAPK pathway and cryptochrome in the early bio-HMF response. Our results provide insights into the molecular mechanisms underlying the observed biological effects of the HMF.

Shielding of the geomagnetic field alters actin assembly and inhibits cell motility in human neuroblastoma cells

Accumulating evidence has shown that absence of the geomagnetic field (GMF), the so-called hypomagnetic field (HMF) environment, alters the biological functions in seemingly non-magnetosensitive cells and organisms, which indicates that the GMF could be sensed by non-iron-rich and non-photo-sensing cells. The underlying mechanisms of the HMF effects on those cells are closely related to their GMF sensation but remain poorly understood so far. Previously, we found that the HMF represses expressions of genes associated with cell migration and cytoskeleton assembly in human neuroblastoma cells (SH-SY5Y cell line). Here, we measured the HMF-induced changes on cell morphology, adhesion, motility and actin cytoskeleton in SH-SY5Y cells. The HMF inhibited cell adhesion and migration accompanied with a reduction in cellular F-actin amount. Moreover, following exposure to the HMF, the number of cell processes was reduced and cells were smaller in size and more round in shape. Furthermore, disordered kinetics of actin assembly in vitro were observed during exposure to the HMF, as evidenced by the presence of granule and meshed products. These results indicate that elimination of the GMF affects assembly of the motility-related actin cytoskeleton, and suggest that F-actin is a target of HMF exposure and probably a mediator of GMF sensation.

Brain Formaldehyde is Related to Water Intake behavior

A promising strategy for the prevention of Alzheimer’s disease (AD) is the identification of age-related changes that place the brain at risk for the disease. Additionally, AD is associated with chronic dehydration, and one of the significant changes that are known to result in metabolic dysfunction is an increase in the endogenous formaldehyde (FA) level. Here, we demonstrate that the levels of uric formaldehyde in AD patients were markedly increased compared with normal controls. The brain formaldehyde levels of wild-type C57 BL/6 mice increased with age, and these increases were followed by decreases in their drinking frequency and water intake. The serum arginine vasopressin (AVP) concentrations were also maintained at a high level in the 10-month-old mice. An intravenous injection of AVP into the tail induced decreases in the drinking frequency and water intake in the mice, and these decreases were associated with increases in brain formaldehyde levels. An ELISA assay revealed that the AVP injection increased both the protein level and the enzymatic activity of semicarbazide-sensitive amine oxidase (SSAO), which is an enzyme that produces formaldehyde. In contrast, the intraperitoneal injection of formaldehyde increased the serum AVP level by increasing the angiotensin II (ANG II) level, and this change was associated with a marked decrease in water intake behavior. These data suggest that the interaction between formaldehyde and AVP affects the water intake behaviors of mice. Furthermore, the highest concentration of formaldehyde in vivo was observed in the morning. Regular water intake is conducive to eliminating endogenous formaldehyde from the human body, particularly when water is consumed in the morning. Establishing good water intake habits not only effectively eliminates excess formaldehyde and other metabolic products but is also expected to yield valuable approaches to reducing the risk of AD prior to the onset of the disease.

Hypomagnetic field, an ignorable environmental factor in space?

All living organisms on the earth have been exposed to the geomagnetic field (GMF, ~50 μT), a nature component of the habitability environment, throughout the evolutionary history. However, the environmental magnetic field (MF) in space decreases geometrically with the distance from the ground. The MF magnitude (|B|) at the International Space Station (ISS; near-earth orbit) is similar to the GMF (~80% GMF with limited variation), except that the radial component (Br) exhibits significant variations both in direction and magnitude [1]. The environmental MF in outer space is extremely lower than the GMF, called a hypomagnetic field (HMF), e.g., Martian MF is <5 μT, Lunar MF is <300 nT and interplanetary MF is just a few nanotesla [2] (Figure 1). Thus, besides micro-gravity (μ-gravity) and cosmic radiation, astronauts have to be exposed and adapt to the HMF condition when onboard in the long-term and long-distance space missions. Even though biological effects of the HMF were valued in early studies (1960s), exploration of the space HMF has not rapidly progressed in the following decades. The reasons may be as follows. First, considering the strength of MF in the near-earth orbit is about 80% of the GMF, the effects of μ-gravity and radiation are more observable than HMF in the short-term and short-distance space missions. Significant attention has been attached to the ground-based simulation experiments of μ-gravity and dosimetry of radiation in the previous space projects and missions. Second, the maintenance of a high quality HMF requires sophisticated instrument and expensive materials, such as highprecision magnetometer, magnetic shielding metal and Figure 1 The environmental magnetic field in outer space and the definition of the hypomagnetic field. A weak static magnetic field with |B|<5 μT is defined as a hypomagnetic field (HMF). Lunar magnetic field range: <300 nT; Martian magnetic field range: 300 nT5 μT. The interplanetary magnetic field is lower than 10 nT. The magnetic intensity is plotted in logarithmic scale (modified from the figure in [2]).

Decline of cell viability and mitochondrial activity in mouse skeletal muscle cell in a hypomagnetic field

Hypomagnetic field (HMF), one of the key environmental risk factors for astronauts traveling in outer space, has previously been shown to repress locomotion of mammalians. However, underlying mechanisms of how HMF affects the motor system remains poorly understood. In this study, we created an HMF (<3 μT) by eliminating geomagnetic field (GMF, ∼50 μT) and exposed primary mouse skeletal muscle cells to this low magnetic field condition for a period of three days. HMF-exposed cells showed a decline in cell viability relative to GMF control, even though cells appeared normal in terms of morphology and survival rate. After a 3-day HMF-exposure, glucose consumption of skeletal muscle cells was significantly lower than GMF control, accompanied by less adenosine triphosphate (ATP) and adenosine diphosphate (ADP) content and higher ADP/ATP ratio. In agreement with these findings, mitochondrial membrane potential of HMF-exposed cells was also lower, whereas levels of cellular Reactive Oxygen Species were higher. Moreover, viability and membrane potential of isolated mitochondria were reduced after 1 h HMF-exposure in vitro. Our results indicate that mitochondria can directly respond to HMF at functional level, and suggest that HMF-induced decline in cell functionality results from a reduction in energy production and mitochondrial activity.

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.