Myelination by oligodendrocytes in the central nervous system requires coordinated exocytosis and endocytosis of the major myelin protein, proteolipid protein (PLP). Here, we demonstrated that a small GTPase, Rab27b, is involved in PLP trafficking in oligodendrocytes. We showed that PLP co-localized with Rab27b in late endosomes/lysosomes in oligodendrocytes. Short hairpin-mediated knockdown of Rab27b not only reduced lysosomal exocytosis but also greatly diminished the surface expression of PLP in oligodendrocytes. In addition, knockdown of Rab27b reduced the myelin-like membranes induced by co-culture of oligodendrocytes and neurons. Our data suggest that Rab27b is involved in myelin biogenesis by regulating PLP transport from late endosomes/lysosomes to the cell membrane in oligodendrocytes.

No abstract

Background: Achyranthes bidentata polypeptide k (ABPPk) is an active ingredient used in traditional Chinese medicine separated from Achyranthes bidentata polypeptides. So far, the role of ABPPk in peripheral nerve protection has not been comprehensively studied.Methods: In this study, primary Schwann cells exposed to serum deprivation were treated with ABPPk or nerve growth factor (NGF) in vitro. Cell viability, cell apoptosis, apoptosis-related protein expression, and antioxidant enzyme activity were analyzed. To further explore the underlying molecular mechanisms and key regulatory molecules involved in the effects of ABPPk, integrative and dynamic bioinformatics analysis at different time points was carried out following RNA-seq of Schwann cells subjected to serum deprivation. Results:We found that ABPPk could effectively reduce Schwann cell apoptosis caused by serum deprivation, which was comparable to NGF's anti-apoptotic effects. ABPPk had the largest number of upregulated and downregulated differential expression genes at the earliest 0.5 h time, while NGF had fewer differential expression genes at this early stage. The significant difference at this time point between the two groups was also displayed in heatmaps. The molecular regulation of diseases and functions and canonical pathways revealed that ABPPk had more participation and advantages in the vasculature and immune system areas, especially angiogenesis regulation. Also, ABPPk demonstrated an earlier start in these molecular regulations than NGF. Furthermore, the analysis of transcription factors also illustrated that ABPPk not only had more key initial regulatory factors participating in vascular-related processes, but these also remained for a longer period. There was no significant difference in neural-related molecular regulation between the two groups.Conclusions: Using high-throughput sequencing technology, our work unveiled the protective effects of ABPPk on Schwann cells after serum deprivation in a more comprehensive manner. These results further enrich the positive functions and molecular mechanisms of ABPPk and traditional Chinese medicine and benefit the discovery of novel therapeutic targets for peripheral nerve regeneration.

Background: Salvia miltiorrhiza is a traditional Chinese medicine with remarkable antioxidant, antibacterial, and anticoagulant properties. In the present study, we investigated the effects of Salvia miltiorrhiza injection in protecting Schwann cells (SCs) from hydrogen peroxide (H 2 O 2 )-induced cell apoptosis.Methods: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and immunofluorescence staining were used to detect the establishment of the SC apoptosis model induced by H 2 O 2 . The effect of Salvia miltiorrhiza injection on injured cell morphology was observed, and the effect on cell apoptosis was determined by Annexin V-fluorescein isothiocyanate (FITC) apoptosis detection kit and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Western blotting analysis was used to detect the effect of Salvia miltiorrhiza injection on apoptosis-related protein expression. Results:The results of the MTT assay showed that cell activity significantly decreased after treatment with 1 mM H 2 O 2 , but different concentrations of Salvia miltiorrhiza injection could improve cell activity at different degrees. The number of cells increased significantly after treatment with Salvia miltiorrhiza injection. Annexin V-FITC/PI double staining and TUNEL results revealed that Salvia miltiorrhiza injection could significantly reduce apoptosis induced by H 2 O 2 . Western blotting analysis showed that the expression of Bcl-2 was significantly upregulated, while the expression level of Bax was significantly downregulated.Conclusions: Salvia miltiorrhiza injection can protect SCs from H 2 O 2 -induced cell apoptosis, and has potential therapeutic effects in neurological disease.

No abstract