Proteomic profiling of sclerotic hippocampus revealed dysregulated packaging of vesicular neurotransmitters in temporal lobe epilepsy
EPILEPSY RESEARCH
Authors: Zhang, Yusheng; Liu, Yifan; Jia, Yangjie; Zhao, Yuming; Ma, Chao; Bao, Xinjie; Meng, Xianbin; Dou, Wanchen; Wang, Xia; Ge, Wei
Abstract
Purpose: Temporal lobe epilepsy (TLE) is the most common type of epilepsy. Hippocampal sclerosis is the most distinctive pathological feature of TLE; however, its role in the pathogenesis of TLE remains to be clarified. We performed global protein expression analysis of hippocampus from TLE patients and controls, aiming to reveal the molecular signaling pathways related to TLE. Method: Proteomic and bioinformatic analyses of the hippocampus were performed on 4 TLE and 4 control samples. High-resolution liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), in combination with TMT-6plex quantification, was applied for global protein expression analysis. The proteomics results were validated by Western blot with 25 TLE and 25 control individuals and Immunohistochemistry analysis with 33 TLE and 10 control individuals. Results: Bioinformatics analysis demonstrated differentially expressed proteins in the synaptic vesicle pathway, the prostaglandin synthesis and regulation pathway and endocannabinoids and retrograde modulation of synaptic transmission pathway. Among these, excitatory amino acid transporter 1 (EAAT1) and Vesicular glutamate transporter 1 (VGLUT1) are critical for TLE and dysregulated expression might be closely related to the uptake of extracellular glutamate and contribute to the pathophysiology of TLE. Ras-related protein Rab-3A (RAB3A) downregulation might indicate the TLE-induced compensatory deficit in glutamate release. Conclusion: Our study indicates that expression of some proteins involved in the packaging of vesicular neurotransmitters is altered in TLE. In addition, upregulated expression of annexin family proteins, which are also related to TLE, might play an important role in protection against TLE.
Long-term stimulation of toll-like receptor-2 and-4 upregulates 5-LO and 15-LO-2 expression thereby inducing a lipid mediator shift in human monocyte-derived macrophages
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR AND CELL BIOLOGY OF LIPIDS
Authors: Ebert, Roland; Cumbana, Rivelino; Lehmann, Christoph; Kutzner, Laura; Toewe, Andy; Ferreiros, Nerea; Parnham, Michael J.; Schebb, Nils H.; Steinhilber, Dieter; Kahnt, Astrid S.
Abstract
Macrophage polarization switches during the course of inflammation along with the lipid mediators released. We investigated the lipid mediator formation in human monocyte-derived macrophages during in vitro differentiation and pathogen stimulation. For this, peripheral blood monocytes were differentiated into M1 (CSF-2/IFN gamma) or M2 (CSF-1/IL-4) macrophages followed by stimulation with the toll-like receptor (TLR) ligands zymosan (TLR-2), Poly(I:C) (TLR-3) or bacterial lipopolysaccharides (TLR-4) mimicking fungal, viral and bacterial infection, respectively. Expression of enzymes involved in lipid mediator formation such as 5- and 15-lipoxygenases (LO), the 5-LO activating protein and cyclooxygenase-2 (COX-2) was monitored on mRNA and protein level and lipid mediator formation was assessed. In addition, cytokine release was measured. In vitro differentiation of human peripheral blood monocytes to M1 and M2 macrophages considerably attenuated 5-LO activity. Furthermore, while TLR-2 and -4 stimulation of M1 macrophages primarily triggered pro-inflammatory cytokines and lipid mediators, persistent stimulation (16 h) of human M2 macrophages induced a coordinated upregulation of 5- and 15-LO-2 expression. This was accompanied by a marked increase in IL-10 and monohydroxylated 15-LO products in the conditioned media of the cells. After additional stimulation with Ca2+ ionophore combined with supplementation of arachidonic, eicosapentaenoic and docosahexaenoic acid these cells also released small amounts of SPM such as lipoxins and resolvins. From this we conclude that activation of TLR-2 or -4 triggers the biosynthesis of pro-inflammatory 5-LO and COX-2 derived lipid mediators in human monocyte-derived M1 macrophages while persistent stimulation of M2 macrophages induces a shift towards proresolving 15-LO derived oxylipins.