Biology subjects

Berryer, M. H.

Publications and source records attributed to Berryer, M. H..

5 recordsLinked to original sources

bioRxiv2026

Applications of adeno-associated virus for 3D single-cell morphometric analysis in iPSC-derived midbrain organoids.

Human midbrain organoids (hMBOs) are emerging in vitro models to mirror the cellular diversity and the structural complexity of the developing human brain. However, the dense neural network, limits the investigation of individual cells morphology or cell-cell connectivity, which is mostly restricted to fixed organoids following extensive optical clearing techniques. To better resolve individual cells within a brain organoid and for longitudinal tracking of its growth and development, we turned to adeno-associated virus (AAVs) for targeted gene delivery. In particular, we applied AAVs for expressing specific markers that provide the foundation to image individual cells within 3D hMBOs. Thus, we developed a phenotypic platform to specifically inspect the neuronal and astrocytic cytoarchitecture and to examine their connectivity in living hMBOs derived from two genetically unrelated control iPSC lines. We demonstrate that through AAV transduction, we could capture and reconstruct the 3D architecture of both neurons and astrocytes within the hMBO as a whole. Transduced cells exhibited an intrinsic heterogeneity in term of soma volume, arbor complexity and territory covered, regardless of both genetic background, age, and cell-type. Yet, these cellular morphometrics remained equivalent between the two cell lines, indicative of homogeneity in hMBO cellular development. We were able to establish longitudinal profiling of transduced cells, demonstrating how neurons and astrocytes could expand their network over time. Lastly, we describe time-lapse studies to track cellular motility and morphology fluctuations in neurons and astrocytes over time, highlighting the dynamic nature of these cells within the ramified architecture of the neural network in the developing hMBOs. Overall, our platform underscores the versatility of AAVs in studying single cell-morphometrics and cellular connectivity for longitudinal monitoring of cellular dynamics in live 3D hMBOs instead of a static snapshot.

neuroscience↗

bioRxiv2026

Integration of iPSC-derived microglia into human midbrain organoids enhances microglial maturation and inflammatory signaling

Microglia are the resident immune cells of the central nervous system and play key roles in the healthy brain during development and adulthood, as well as during neurodegenerative diseases - including Parkinsons disease (PD). Yet the role of microglia in PD pathogenesis has not been fully elucidated. Limitations of 2D cell culture and animal models in simulating human microglia in the brain parenchyma have contributed to this knowledge gap. Human midbrain organoids (hMOs) provide a promising model that can recapitulate elements of PD pathology but lack microglial cells. Here we adapt protocols for the differentiation of hMOs and human iPSC-derived microglia (iMG) to generate iMG-hMO assembloids. Within assembloids, integrated iMG (intMG) express canonical microglia markers and induce the release of cytokines and chemokines. Transcriptomic profiling by single cell RNA sequencing reveals that intMG adopt a more mature and inflammation-responsive state compared to 2D iMG. The integration of microglia results in increased signaling through inflammatory and trophic pathways that drive altered transcriptional signatures of dopaminergic neurons and astrocytes within assembloids. Overall, iMG-hMO assembloids have the potential to more faithfully model the role of microglia and neuroinflammation in PD pathogenesis.

neuroscience↗

bioRxiv2024

p75NTR upregulation following perinatal hypoxia leads to deficits in parvalbumin-expressing GABAergic cell maturation, cortical activity and cognitive abilities in adult mice

Children who experienced moderate perinatal hypoxia are at risk of developing long lasting subtle cognitive and behavioral deficits, including learning disabilities and emotional problems. Understanding the underlying mechanisms is an essential step for designing targeted therapy. Fast-spiking, parvalbumin-positive (PV) GABAergic interneurons modulate the generation of gamma oscillations, which in turn regulate many cognitive functions including goal-directed attentional processing and cognitive flexibility. Due to their fast firing rate, PV cell function requires high levels of energy, which may render them highly vulnerable to conditions of metabolic and oxidative stress caused by perinatal hypoxia. Here, we show that adult mice that experienced moderate perinatal hypoxia (MPH) have decreased cortical PV expression levels in addition to specific impairments in the social, recognition memory and cognitive flexibility domain. We further found that the expression level of the neurotrophin receptor p75NTR, which limits PV cell maturation during the first postnatal weeks, is increased in MPH mice. Genetic deletion of p75NTR in GABAergic neurons expressing the transcription factor Nkx2.1, which include PV cells, protects mice from PV expression loss and the long-term cognitive effects of MPH. Finally, one week treatment with a p75NTR inhibitor starting after MPH completely rescues the cognitive and cortical activity deficits in adult mice. All together this data reveals a potential molecular target for the treatment of the cognitive alterations caused by MPH.

neuroscience↗

bioRxiv2022

Robust induction of functional astrocytes using NGN2 expression in human pluripotent stem cells

Astrocytes play essential roles in normal brain function, with dysfunction implicated in diverse developmental and degenerative disease processes. Emerging evidence of profound species divergent features of astrocytes coupled with the relative inaccessibility of human brain tissue underscore the utility of human pluripotent stem cell (hPSC) technologies for the generation and study of human astrocytes. However, existing approaches for hPSC-astrocyte generation are typically lengthy, incompletely characterized, or require intermediate purification steps, limiting their utility for multi-cell line, adequately powered functional studies. Here, we establish a rapid and highly scalable method for generating functional human induced astrocytes (hiAs) based upon transient Neurogenin 2 (NGN2) induction of neural progenitor-like cells followed by maturation in astrocyte media, which demonstrate remarkable homogeneity within the population and across 11 independent cell lines in the absence of additional purification steps. These hiAs express canonical astrocyte markers, respond to pro-inflammatory stimuli, exhibit ATP-induced calcium transients and support neuronal maturation in vitro. Moreover, single-cell transcriptomic analyses reveal the generation of highly reproducible cell populations across individual donors, most closely resembling human fetal astrocytes, and highly similar to hPSC-derived astrocytes generated using more complex approaches. Finally, the hiAs capture key molecular hallmarks in a trisomy 21 disease model. Thus, hiAs provide a valuable and practical resource well-suited for study of basic human astrocyte function and dysfunction in disease.

neuroscience↗

bioRxiv2022

An automated high-content synaptic phenotyping platform in human neurons and astrocytes reveals a role for BET proteins in synapse assembly

Resolving fundamental molecular and functional processes underlying human synaptic development is crucial for understanding normal brain function as well as dysfunction in disease. Based upon increasing evidence of species divergent features of brain cell types, coupled with emerging studies of complex human disease genetics, we developed the first automated and quantitative high-content synaptic phenotyping platform using human neurons and astrocytes. To establish the robustness of our platform, we screened the effects of 376 small molecules on presynaptic density, neurite outgrowth and cell viability, validating six small molecules which specifically enhanced human presynaptic density in vitro. Astrocytes were essential for mediating the effects of all six small molecules, underscoring the relevance of non-cell autonomous factors in synapse assembly and their importance in synaptic screening applications. Bromodomain and extraterminal (BET) inhibitors emerged as the most prominent hit class and global transcriptional analyses using multiple BET inhibitors confirmed upregulation of synaptic gene expression programs. Through these analyses, we demonstrate the robustness of our automated screening platform for identifying potent synaptic modulators, which can be further leveraged for scaled analyses of human synaptic mechanisms and drug discovery efforts.

neuroscience↗