NO up-regulates migraine-related CGRP via activation of an Akt/GSK-3ß/NF-κB signaling cascade in trigeminal ganglion neurons.

The release of the neuropeptide CGRP from the trigeminal ganglion neurons (TGNs) plays a central role in migraine. Whereas CGRP can activate NO release from ganglionic glial cells, NO in turn enhances CGRP release. However, it remains unclear how NO promotes CGRP release. Here, we report that the NO donor SNAP triggered CGRP release from cultured primary TGNs. This event was associated with GSK-3ß activation and Akt inactivation. Immunofluorescent staining revealed that GSK-3ß primarily located in neurons. Furthermore, GSK-3ß inhibition resulted in a marked reduction in expression of CGRP as well as other migraine-related factors, including substance P, cholecystokinin, and prostaglandin E2. Last, exposure to SNAP also activated NF-κB, while NF-κB inhibition prevented the induction of CGRP by SNAP. Interestingly, this event was blocked by GSK-3ß inhibition, in association with inhibition of NF-κB/p65 expression and nuclear translocation. Together, these findings argue that NO could stimulate TGNs to release of CGRP as well as other migraine-related factors, likely by activating GSK-3ß, providing a novel mechanism underlying a potential feed-forward loop between NO and CGRP in migraine. They also raise a possibility that GSK-3ß might act to trigger migraine through activation of NF-κB, suggesting a link between neuroinflammation and migraine.

A Novel PL9 Pectate Lyase from Paenibacillus polymyxa KF-1: Cloning, Expression, and Its Application in Pectin Degradation.

Pectate lyases play an important role in pectin degradation, and therefore are highly useful in the food and textile industries. Here, we report on the cloning of an alkaline pectate lyase gene (pppel9a) from Paenibacillus polymyxa KF-1. The full-length gene (1350 bp) encodes for a 449-residue protein that belongs to the polysaccharide lyase family 9 (PL9). Recombinant PpPel9a produced in Escherichia coli was purified to electrophoretic homogeneity in a single step using Ni2+-NTA affinity chromatography. The enzyme activity of PpPel9a (apparent molecular weight of 45.3 kDa) was found to be optimal at pH 10.0 and 40 °C, with substrate preference for homogalacturonan type (HG) pectins vis-à-vis rhamnogalacturonan-I (RG-I) type pectins. Using HG-type pectins as substrate, PpPel9a showed greater activity with de-esterified HGs. In addition, PpPel9a was active against water-soluble pectins isolated from different plants. Using this lyase, we degraded citrus pectin, purified fractions using Diethylaminoethyl (DEAE)-sepharose column chromatography, and characterized the main fraction MCP-0.3. High-performance gel permeation chromatography (HPGPC) analysis showed that the molecular mass of citrus pectin (~230.2 kDa) was reduced to ~24 kDa upon degradation. Ultra-performance liquid chromatography - tandem mass spectrometer (UPLC-MS) and monosaccharide composition analyses demonstrated that PpPel9a worked as an endo-pectate lyase, which acted primarily on the HG domain of citrus pectin. In vitro testing showed that the degradation product MCP-0.3 significantly promotes the growth of Lactobacillus plantarum and L. rhamnosus. In this regard, the enzyme has potential in the preparation of pharmacologically active pectin products.

Size-Tunable Low Molecular Weight Pectin-Based Electrospun Nanofibers Blended with Low Content of Poly(ethylene oxide).

Pectin, a natural plant polysaccharide, holds great potential for biomedicine. Developing low molecular weight (Mw) pectin-based nanofibers is desirable for biomedical applications in which fast degradation and elimination of polymer from the body are required. Here, we report the first work on fabricating low Mw pectin-based nanofibers through electrospinning, among which the content of carrier polymer, poly(ethylene oxide) (PEO), can be minimized to 10%. Surfactant (Triton X-100), high polymer concentration and cosolvent were essential to electrospin bead-free nanofibers at low PEO content. The size of pectin nanofibers was dependent on polymer concentration and cosolvent. The presence of cosolvent inhibited the crystallization of PEO, but enhanced the crystallization of pectin. Meanwhile, glycerol as cosolvent could lead to phase separation of polymers. This work provides a new prospective for the fabrication of low Mw pectin nanofibers suitable for in vivo applications with the demand of fast degradation.