Biology subjects

Marshe, V.

Publications and source records attributed to Marshe, V..

3 recordsLinked to original sources

bioRxiv2025

Transcriptional regulation of disease-relevant microglial activation programs

Microglia, the brains innate immune cells, can adopt a wide variety of activation states relevant to health and disease. Dysregulation of microglial activation occurs in numerous brain disorders, and driving or inhibiting specific states could be therapeutic. To discover regulators of microglia activation states, we conducted CRISPR interference screens in iPSC-derived microglia for inhibitors and activators of six microglial states. We characterized 31 regulators at the single-cell transcriptomic and cell-surface proteome level in two distinct iPSC-derived microglia models, uncovering new protein markers of relevant states. We functionally characterized several multi- state regulators. ZNF532 and PRDM1 knockdown drive disease-associated, lipid-rich signatures and enhance phagocytosis while showing opposing effects on antigen-presentation signatures. DNMT1 knockdown results in widespread loss of methylation, activating negative regulators of interferon signaling. These findings provide a framework to direct microglial activation to selectively enrich microglial activation states, define their functional outputs, and inform future therapies. HighlightsO_LICRISPRi screening reveals novel regulators of six microglia activation states C_LIO_LIMulti-modal single-cell screens highlight new markers of microglial states C_LIO_LIDifferent iPSC-microglia models show different landscapes of activation states at baseline C_LIO_LILoss of DNMT1 leads to widespread DNA demethylation, promoting some states but limiting the interferon-response state C_LIO_LILoss of PRDM1 or ZNF532 drives the microglial disease-associated state C_LI

neuroscience↗

bioRxiv2025

A proteogenomic tool uncovers protein markers for human microglial states

Human microglial heterogeneity has been largely described using transcriptomic data. Here, we introduce a microglial proteomic data resource and a Cellular Indexing of Transcriptomes and Epitopes by Sequencing panel enhanced with antibodies targeting 17 microglial cell surface proteins (mCITE-Seq). We evaluated mCITE-Seq on HMC3 microglia-like cells, induced-pluripotent stem cell-derived microglia (iMG), and freshly isolated primary human microglia. We identified novel protein microglial markers such as CD51 and relate expression of 101 cell surface proteins to transcriptional programs. This results in the identification and validation of three protein marker combinations with which to purify microglia enriched with each of 23 transcriptional programs; for example, CD49D, HLA-DR and CD32 enrich for GPNMBhigh ("disease associated") microglia. Further, we identify and validate proteins - SIRPA, PDPN and CD162 - that differentiate microglia from infiltrating macrophages. The mCITE-Seq panel enables the transition from RNA-based classification and facilitates the functional characterization and harmonization of model systems.

neuroscience↗

bioRxiv2024

HDAC Inhibitors recapitulate Human Disease-Associated Microglia Signatures in vitro

Disease-associated microglia (DAM), initially described in mouse models of neurodegenerative diseases, have been classified into two related states; starting from a TREM2-independent DAM1 state to a TREM2 dependent state termed DAM2, with each state being characterized by the expression of specific marker genes1. Recently, single-cell (sc)RNA-Seq studies have reported the existence of DAMs in humans2-6; however, whether DAMs play beneficial or detrimental roles in the context of neurodegeneration is still under debate7,8. Here, we present a pharmacological approach to mimic human DAM in vitro by exposing different human microglia models to selected histone deacetylase (HDAC) inhibitors. We also provide an initial functional characterization of our model system, showing a specific increase of amyloid beta phagocytosis along with a reduction of MCP-1 secretion. Additionally, we report an increase in MITF expression, a transcription factor previously described to drive expression towards the DAM phenotype. We further identify CADM1, LIPA and SCIN as DAM- marker genes shared across various proposed DAM signatures and in our model systems. Overall, our strategy for targeted microglial polarization bears great potential to further explore human DAM function and biology.

neuroscience↗