Acute doses of caffeine shift nervous system cell expression profiles toward promotion of neuronal projection growth

Abstract

Caffeine is a widely consumed psychoactive substance, but little is known about the effects of caffeine stimulation on global gene expression changes in neurons. Here, we conducted gene expression profiling of human neuroepithelial stem cell-derived neurons, stimulated with normal consumption levels of caffeine (3 μM and 10 μM), over a period of 9 h. We found dosage-dependent activation of immediate early genes after 1 h. Neuronal projection development processes were up-regulated and negative regulation of axon extension processes were down-regulated at 3 h. In addition, genes involved in extracellular matrix organization, response for wound healing, and regulation of immune system processes were down-regulated by caffeine at 3 h. This study identified novel genes within the neuronal projection guidance pathways that respond to acute caffeine stimulation and suggests potential mechanisms for the effects of caffeine on neuronal cells.

Oligomeric amyloid-β induces early and widespread changes to the proteome in human iPSC-derived neurons

“…Differentiated cells were predominantly neurons as determined by their expression of the neuronal nuclear marker NeuN (AF22 = 78.5 ± 5.4%, ADP2 = 84.5 ± 9.0%), consistent with previous studies using these ltNES cells ( Supplementary Fig. S1) [14][15][16][17][18][19][20][21] . After 24 h incubation with the oAβ, cells were collected, and proteins extracted for whole proteome or phosphoproteome analysis by nLC-MS/MS (summarized in Fig.…”

“…In this work, we aim to elucidate intracellular protein changes elicited by oAβ upon naïve human neurons, thereby furthering our understanding of the early mediators involved in Aβ-induced pathogenesis. To do this, we used well characterized iPSC-derived ltNES cells, which upon differentiation, are electrophysiologically mature and display mature neuronal markers [14][15][16][17][18][19][20][21] . Since Aβ oligomers are thought to be the most relevant aggregates in AD pathology, we challenged the differentiated neurons with 1 µM oAβ over 24 h to mimic the early phase of oAβ challenge, similar to previous studies 22,23,[26][27][28][29][30] .…”

“…As recently shown by Volpato et al, it is important to consider the reproducibility of iPSC-derived cells with respect to expressional variations between laboratories 76 . In this study, we have utilized thoroughly characterized iPSC-derived ltNES cells, which have been widely used in several different laboratories to derive neurons for in vitro studies [14][15][16][17][18][19][20][21] . Importantly, these cells have been demonstrated to maintain stable morphology, differentiation potential and gene expression profiles over more than 100 passages 14 and display consistent expression profiles across different laboratories 15,16,18,19 .…”

“…In this study, we have utilized thoroughly characterized iPSC-derived ltNES cells, which have been widely used in several different laboratories to derive neurons for in vitro studies [14][15][16][17][18][19][20][21] . Importantly, these cells have been demonstrated to maintain stable morphology, differentiation potential and gene expression profiles over more than 100 passages 14 and display consistent expression profiles across different laboratories 15,16,18,19 . Using the same differentiation scheme as previously described for these ltNES cells 14 , we found similar proportions of neurons to glia upon differentiation as those previously described 14,16,18,19 .…”

“…While targeted interaction studies like those involving Aβ and tau have been the subject of many studies, unbiased proteomics approaches to understanding changes to the proteome in response to Aβ are lacking, leaving a significant gap in the understanding of how oAβ induces pathology in naïve human neurons. In this study, we use two well characterized human neuronal cellular models derived from human iPSCs: one harbouring wild-type amyloid precursor protein (APP; AF22) and another with the London APP (V717I) mutation (ADP2) [14][15][16][17][18][19][20][21] . Using LC-MS/MS and label-free quantification, we investigated the early changes to the proteome and phosphoproteome after neurons were challenged with oAβ, simulating a cellular environment comparable to early oAβ pathology in AD [22][23][24][25] .…”