Joachim, S. C. | Search bioRxiv

bioRxiv2023

Neural extracellular matrix regulates visual sensory motor integration

Visual processing depends on sensitive and balanced synaptic neurotransmission. Extracellular matrix proteins in the environment of cells are key modulators in synaptogenesis and synaptic plasticity. In the present study, we provide evidence that the combined loss of the four extracellular matrix components brevican, neurocan, tenascin-C and tenascin-R in quadruple knockout mice leads to severe retinal dysfunction and diminished visual motion processing in vivo. Remarkably, impaired visual motion processing was accompanied by a developmental loss of cholinergic direction-selective starburst amacrine cells. Additionally, we noted imbalance of inhibitory and excitatory synaptic signaling in the quadruple knockout retina. Collectively, the study offers novel insights into the functional importance of four key extracellular matrix proteins for retinal function, visual motion processing and synaptic integrity. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=73 SRC="FIGDIR/small/537074v1_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@eec571org.highwire.dtl.DTLVardef@1e4b282org.highwire.dtl.DTLVardef@18398a7org.highwire.dtl.DTLVardef@9b113b_HPS_FORMAT_FIGEXP M_FIG C_FIG In briefIn their study, Reinhard et al. show that the combined loss of the extracellular matrix components brevican, neurocan, tenascin-C and tenascin-R in quadruple knockout mice leads to retinal dysfunction, diminished visual motion processing, developmental loss of cholinergic direction-selective starburst amacrine cells and imbalance of inhibitory and excitatory synaptic integrity. HighlightsO_LICombined loss of the four extracellular matrix molecules brevican, neurocan, tenascin-C and tenascin-R causes retinal dysfunction C_LIO_LIImpaired visual motion processing in quadruple, tenascin-C and tenascin-R knockout mice C_LIO_LILoss of cholinergic direction-selective starburst amacrine cells in the quadruple knockout retina C_LIO_LIThe matrisome influences inhibitory and excitatory synaptic balance C_LI

neuroscience↗

bioRxiv2022

Protein profiling of WERI RB1 and etoposide resistant WERI ETOR reveals new insights into topoisomerase inhibitor resistance in retinoblastoma

Chemotherapy resistance is one of the reasons for eye loss in patients with retinoblastoma (RB). RB chemotherapy resistance has been studied in different cell culture models such as WERI RB1. In addition, chemotherapy resistant RB subclones like the etoposide resistant WERI ETOR cell line have been established to improve the understanding of chemotherapy resistance in RB. The objective of this study was to characterize cell line models of an etoposide sensitive WERI RB1 and its etoposide resistant subclone WERI ETOR by proteomic analysis. Subsequently, quantitative proteomic data served for correlation analysis with known drug perturbation profiles. Methodically, WERI RB1 and WERI ETOR were cultured and prepared for quantitative mass spectrometry (MS). This was carried out in a data-independent acquisition (DIA) mode (Sequential Window Acquisition of All Theoretical Mass Spectra, SWATH-MS). The raw SWATH files were processed using neural networks in a library free mode along with machine learning algorithms. Pathway enrichment was performed using the REACTOME pathway resource and correlated to the Molecular Signature Database (MSigDB) hallmark gene set collections for functional annotation. Furthermore, a drug connectivity analysis using the L1000 database was used to correlate the mechanism-of-action (MOA) for different anticancer reagents to WERI RB1/WERI ETOR signatures. A total of 4,756 proteins were identified across all samples, showing a distinct clustering between the groups. Of these proteins, 64 were significantly altered (q < 0.05 & log2FC |>2|, 22% higher in WERI ETOR). Pathway analysis revealed an enriched metabolic pathway for "retinoid metabolism and transport" in WERI ETOR and for "sphingolipid de novo biosynthesis" in WERI RB1. In addition, this study revealed similar protein signatures of topoisomerase inhibitors in WERI ETOR as well as ATPase inhibitors, acetylcholine receptor antagonists and vascular endothelial growth factor receptor (VEGFR) inhibitors in WERI RB1. In this study, WERI RB1 and WERI ETOR were analyzed as a cell line model for chemotherapy resistance in RB using data-independent MS. The global proteome identified activation of "sphingolipid de novo biosynthesis" in WERI RB1 and revealed future potential treatment options for etoposide resistance in RB.

cancer biology↗