Biology subjects

Piester, G.

Publications and source records attributed to Piester, G..

4 recordsLinked to original sources

bioRxiv2026

Adult human ex vivo brain slices for dissecting glial biology and multicellular communication

Glial cells are critical modulators of brain function in health, aging, and disease, emerging as promising therapeutic targets. However, exploring their roles and therapeutic potential is limited by the lack of experimental systems that faithfully capture the repertoire of mature human glial cells while permitting controlled perturbations. Here, we establish a robust ex vivo platform for cell-type specific interrogation of glial responses and multicellular crosstalk, based on adult human organotypic brain slice cultures, obtained from neurosurgical resections. We show that slice cultures preserve tissue architecture, maintain all major cell types and mature cellular identities over weeks in culture. These cultures elicit robust, stimulus-specific transcriptional programs to diverse stressors and inflammatory stimuli, demonstrating sensitivity to distinguish closely related signals and reproducibility despite biological and technical variation. Moreover, we resolved coordinated glial cell type-specific responses to TNF, a key mediator of neuroinflammation, uncovering distinct and physiologically relevant functional roles validated in postmortem human brains. Network analyses discovered balanced pro- and anti-inflammatory loops among microglia and astrocyte cells, which notably also involved oligodendrocyte precursor cells (OPCs), confirming their suggested role in regulation of the tissue level inflammatory response in human brains. We experimentally validated that glial activation in slice cultures is orchestrated not only by direct stimulation but also through intercellular signaling across cell types, mirroring natural multicellular dynamics in brain tissue. Together, organotypic brain slice cultures emerge as a sensitive and robust platform for dissecting adult human glial biology, paving the way for deeper mechanistic insights and advanced drug-screening applications.

neuroscience↗

bioRxiv2025

Detection of astrocyte epigenetic memory in in vitro systems, experimental autoimmune encephalomyelitis and multiple sclerosis samples

We recently described astrocyte pro-inflammatory epigenetic memory based on multiple complementary in vivo and in vitro studies, and the analysis of multiple sclerosis samples. Based on bioinformatic analyses, ODea and Liddelow argued that the astrocyte epigenetic memory we described is the result of contamination with immune cells, particularly myeloid cells. We rebut ODea and Liddelow arguments as follows: (1) We show substantial purity of astrocytes analyzed in in vivo and in vitro systems; (2) We recapitulate astrocyte memory responses using five independent pure astrocyte in vitro systems, and show its dependency on the histone acetyl transferase p300; and (3) Using the Liddelow lab bioinformatic pipeline to implement purity and cell-quality criteria, we detect astrocyte epigenetic memory in five independent scRNA-seq experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS) astrocyte datasets. These additional analyses and studies provide further support for the existence of astrocyte pro-inflammatory epigenetic memory.

neuroscience↗

bioRxiv2024

Disease-associated astrocyte epigenetic memory promotes CNS pathology

Astrocytes play important roles in the central nervous system (CNS) physiology and pathology. Indeed, astrocyte subsets defined by specific transcriptional activation states contribute to the pathology of neurologic diseases, including multiple sclerosis (MS) and its pre-clinical model experimental autoimmune encephalomyelitis (EAE)1-8. However, little is known about the stability of these disease-associated astrocyte subsets, their regulation, and whether they integrate past stimulation events to respond to subsequent challenges. Here, we describe the identification of an epigenetically controlled memory astrocyte subset which exhibits exacerbated pro-inflammatory responses upon re-challenge. Specifically, using a combination of single-cell RNA sequencing (scRNA-seq), assay for transposase-accessible chromatin with sequencing (ATAC-seq), chromatin immunoprecipitation with sequencing (ChIP-seq), focused interrogation of cells by nucleic acid detection and sequencing (FIND-seq), and cell-specific in vivo CRISPR/Cas9-based genetic perturbation studies we established that astrocyte memory is controlled by the metabolic enzyme ATP citrate lyase (ACLY), which produces acetyl coenzyme A (acetyl-CoA) used by the histone acetyltransferase p300 to control chromatin accessibility. ACLY+p300+ memory astrocytes are increased in acute and chronic EAE models; the genetic targeting of ACLY+ p300+ astrocytes using CRISPR/Cas9 ameliorated EAE. We also detected responses consistent with a pro-inflammatory memory phenotype in human astrocytes in vitro; scRNA-seq and immunohistochemistry studies detected increased ACLY+ p300+ astrocytes in chronic MS lesions. In summary, these studies define an epigenetically controlled memory astrocyte subset that promotes CNS pathology in EAE and, potentially, MS. These findings may guide novel therapeutic approaches for MS and other neurologic diseases.

immunology↗

bioRxiv2023

Engineered probiotics limit CNS autoimmunity by stabilizing HIF-1α in dendritic cells

Dendritic cells (DCs) control the generation of self-reactive pathogenic T cells. Thus, DCs are considered attractive therapeutic targets for autoimmune diseases. Using single-cell and bulk transcriptional and metabolic analyses in combination with cell-specific gene perturbation studies we identified a negative feedback regulatory pathway that operates in DCs to limit immunopathology. Specifically, we found that lactate, produced by activated DCs and other immune cells, boosts NDUFA4L2 expression through a mechanism mediated by HIF-1. NDUFA4L2 limits the production of mitochondrial reactive oxygen species that activate XBP1-driven transcriptional modules in DCs involved in the control of pathogenic autoimmune T cells. Moreover, we engineered a probiotic that produces lactate and suppresses T-cell autoimmunity in the central nervous system via the activation of HIF-1/NDUFA4L2 signaling in DCs. In summary, we identified an immunometabolic pathway that regulates DC function, and developed a synthetic probiotic for its therapeutic activation.

immunology↗