Chemotactic responses of neural stem cells to SDF-1α correlate closely with their differentiation status.

Chemotaxis of neural stem/progenitor cells (NSCs) is regulated by a variety of factors, and much effort has been devoted to the delineation of factors that are involved in NSC migration. However, the relationship between NSC chemotactic migration and differentiation remains uncharacterized. In the present study, by comparing the transfilter migration rate, single-cell migration speed, and directional efficiency of NSCs in stromal cell-derived factor-1 alpha (SDF-1α)-induced Boyden chamber and Dunn chamber chemotaxis assays, we demonstrate that NSCs in varying differentiation stages possess different migratory capacity. Furthermore, F-actin microfilament reorganization upon stimulation varies greatly among separate differentiation states. We show that signaling pathways involved in NSC migration, such as PI3K/Akt and mitogen-activated protein kinase (MAPK) (ERK1/2, JNK, and p38 MAPK) pathways, are differentially activated by SDF-1α among each NSC differentiation stages, and the extent to which these pathways participate in cell chemotaxis exhibits a differentiation stage-dependent manner. Taken together, these results suggest that the differentiation of NSCs influences their chemotactic responses to SDF-1α, providing new insight into the optimization of the therapeutic efficacy of NSCs for neural regeneration and nerve repair after injury.

Residues and dynamics of kasugamycin in chilli and soil.

A simple and efficient method for determination of kasugamycin in chilli and soil was developed, and the fate of kasugamycin in chilli field ecosystem was also studied. Kasugamycin residues were extracted from sample, cleaned up by solid phase extraction and chromatographic column and then determined by ultra performance liquid chromatography with tandem mass spectrometry detection. The method got recoveries ranged from 77.82% to 83.35% with relative standard deviations of 2.20%-6.54%. As far as the accuracy and precision was concerned, the method met certain standard. The LODs of kasugamycin calculated as a sample concentration (S/N ratio of 3) was 2.50 µg kg(-1). The degradation of kasugamycin in chilli and soil was determined. The results showed that kasugamycin degradation in chilli plant and soil followed the first-order kinetics. The half-lives of kasugamycin in chilli and soil was 2.76-3.77 and 3.07-3.91 days, respectively. The final kasugamycin residues in chilli and soil were undetectable at levels of recommended and 1.5 times recommended dosage with an interval of 21 days.

Differentiation of neural stem cells influences their chemotactic responses to vascular endothelial growth factor.

Although much effort has been devoted to the delineation of factors involved in the migration of neural stem/progenitor cells (NSCs), the relationship between the chemotactic response and the differentiation status of these cells remains elusive. In the present study, we found that NSCs in varying differentiation states possess different chemotactic responses to vascular endothelial growth factor (VEGF): first, the number of chemotaxing NSCs and the optimal concentrations of VEGF that induced the peak migration vary greatly; second, time-lapse video analysis shows that NSCs at certain differentiation states migrate more efficiently toward VEGF, although the migration speed remains unchanged irrespective of cell states; third, the phosphorylation status of Akt, ERK1/2, SAPK/JNK, and p38MAPK is closely related to the differentiation levels of NSCs subjected to VEGF; and, finally, although inhibition of ERK1/2 signaling significantly attenuates VEGF-stimulated transfilter migration of both undifferentiated and differentiating NSCs, NSCs show normal chemotactic response after treatment with inhibitors of SAPK/JNK or p38MAPK. Meanwhile, interference with PI3K/Akt signaling prevents only NSCs of 12 hr differentiation, but not NSCs of 1 day or 3 days differentiation, from migrating in response to VEGF. Moreover, blocking of PI3K/Akt or MAPK signaling impairs the migration efficiency and/or speed, the extent of which depends on the cell differentiation status. Collectively, these results demonstrate that differentiation of NSCs influences their chemotactic responses to VEGF: NSCs in varying differentiation states have different migratory capacities, thereby shedding light on optimization of the therapeutic potential of NSCs to be employed for neural regeneration after injury.