Precursor ion charge condition screening was enabled, and all unassigned charge says as well as singly, septuply, and octuply charged species were rejected. could have important consequences for the abundance of A and in Alzheimer’s disease pathology. gene) were measured in human frontal cortex, hippocampus, temporal cortex, and cerebellum tissues. Given that matriptase expression in epithelial cells of intestinal and especially of colon tissue is usually high (26), the level of matriptase mRNA in the brain region was expressed relative to its expression in colon. Matriptase transcripts were clearly detectable in the frontal cortex, hippocampus, temporal cortex, and cerebellum with no significant difference between the regions tested but at much lower levels than in colon tissue CAB39L (Fig. 1mRNA were analyzed in the human frontal (= 18), temporal (= 8), hippocampus (= 5), and cerebellum (= 7) and expressed relative to that in the human colon tissue (= 3). The difference between the different brain regions was not significant (Student’s test, 0.05). represent means S.D. mRNA were analyzed in human neurons, astrocytes, microvascular endothelial cells (and mRNAs across development in the DLPC as measured by fragments per kilobase of exon per million fragments mapped (represents data from an individual brain. Negative correlation between ages after birth and was significant (Spearman’s correlation coefficient = ?0.73, 0.001) (= 39). To ascertain in which cells of the human nervous system matriptase is expressed, RT-qPCR was next performed on total human mRNA from Doripenem Hydrate different cell types (Fig. 1transcripts in these cells were expressed relative to those of human colon carcinoma cells HCT116 (27). Matriptase mRNA was detected in neurons, astrocytes, microvascular endothelial cells, and choroid plexus epithelial cells, whereas no matriptase mRNA was detected in Schwann cells. Interestingly, the mRNA level in neurons was comparable to that for human epithelial colorectal adenocarcinoma Caco-2/15 cells. Together, these results reveal matriptase expression in different cell types of the human brain and are in agreement with previous data obtained from mouse brain (22). Because matriptase was shown to be expressed in mouse differentiating neural progenitor cells (22), we used human induced pluripotent stem cells (hiPSCs) at different stages of neuronal differentiation (0, 1, 3, and 6 weeks) to analyze matriptase protein expression (Fig. 1 0.001), whereas no correlation was observed for the housekeeping gene conversation between matriptase and the extracellular region of APP695 (GST-APP695 N-term) and/or the cytoplasmic region of APP695 (GST-APP695 C-term) (Fig. 3translated matriptase coprecipitated with GST-APP695 N-term but very weakly with GST-APP695 C-term or GST alone (Fig. 3 0.05) (Fig. 3= 3 for each APP isoforms). Open in a separate window Physique 3. conversation of matriptase with the ectodomain of APP695. translated 35S-labeled matriptase. Bound proteins were separated by SDS-PAGE and detected by autoradiography. GST proteins were detected with Coomassie Blue staining. translated product (= 6). was applied. There is a statistical difference between GST alone and GST-APP695 N-term and between GST-APP695 C-term and GST-APP695 N-term (*, 0.05). represent means S.D. Matriptase cleaves APP When performing immunoprecipitation with GFP-tagged APP and matriptase, we detected a GFP-APP fragment of 35 kDa in cell lysates (Fig. 2and = 3 for each isoform). Note the GFP-tagged APP fragment (cleaved) of 35 kDa in cell lysate and medium (= 3). Note the APP fragment (cleaved) of 10 kDa. translated 35S-labeled APP770 (= 3). Note the APP fragment (cleaved) of 10 kDa (cleavage assays were performed with 35S-labeled translated APP770, APP751, and Doripenem Hydrate APP695, and purified soluble WT matriptase or matriptase S805A (Fig. 4incubation of purified GST-APP695 N-term with or without soluble recombinant WT matriptase. Isolated GST-APP695 fragments were digested with chymotrypsin to produce several overlapping peptides, analyzed by HPLC coupled to an Orbitrap MS, and compared with purified GST-APP695 N-term alone (Fig. 5digestion and LC-MS/MS analysis of GST-APP695 ectodomain fragments generated by matriptase cleavage. Shown is usually a Doripenem Hydrate representative annotated MS/MS fragmentation spectrum with the identified matched N terminus-containing ions (b ions) in and the C terminus-containing ions (y ions) in = 3). Note.