This study generates and characterizes human brain border-associated macrophages (BAMs) using iPSC-derived models, showing a conserved hyper-endocytic phenotype across species.

bioRxiv · Dec 14, 2025 · PreprintNeuroscience

The circadian clock regulates scavenging of fluid-borne substrates by brain border-associated macrophages

Helena J. Barr, Sydney K. Caldwell, Justin M. Reimertz, Constanze Depp, Alec J. Walker, Samuel E. Marsh, Anushree S. Gupte, Maximilian Hingerl, Jasmin Patel, Sang-O Park, Sarah Ferraro, Jonathan Lipton, Beth Stevens

This study identifies brain border-associated macrophages (BAMs) as rhythmic cells regulated by the circadian clock, showing that their endocytic activity and amyloid-beta uptake are disrupted with age and in a mouse model of Alzheimer's disease.

bioRxiv · Dec 11, 2025 · PreprintNeuroscience

Early-life stromal niches orchestrate B lymphopoiesis at the brain's borders

Alec J. Walker, Theodore M. Fisher, Sydney K. Caldwell, Anushree S. Gupte, Justin M. Reimertz, Bristy Sabikunnahar, Samuel E. Marsh, Yvanka de Soysa, Vahid Gazestani, Alicia C. Walker, Youtong Huang, Ananya Mavinkurve, Helena J. Barr, Toby Black Lanser, Sarah R. Murphy, , Beth Stevens

This study identifies the murine dura mater as a transient niche for early-postnatal B lymphopoiesis, highlighting the role of CXCL12-expressing fibroblasts in supporting B cell development.

bioRxiv · Nov 27, 2025 · PreprintImmunology

A resource for generating and manipulating human microglial states in vitro

Michael-John Dolan, Martine Therrien, Saša Jereb, Tushar Kamath, Vahid Gazestani, Trevor Atkeson, Samuel E. Marsh, Aleksandrina Goeva, Neal M. Lojek, Sarah Murphy, Cassandra White, Julia Joung, Bingxu Liu, Francesco Limone, Kevin C. Eggan, , Beth Stevens

This paper develops a platform to model and manipulate human microglial states in vitro using single-cell RNA sequencing and genetic tools, identifying disease-associated transcriptional signatures.

Nature Immunology · Jul 27, 2023Peer-reviewedNeuroscience

Early Alzheimer's disease pathology in human cortex is associated with a transient phase of distinct cell states

Vahid Gazestani, Tushar Kamath, Naeem M. Nadaf, S.J. Burris, Brendan Rooney, Antti Junkkari, Charles R. Vanderburg, Tuomas H. Rauramaa, Martine Therrien, Matthew Tegtmeyer, Sanna‐Kaisa Herukka, Abdulraouf Abdulraouf, Samuel E. Marsh, Tarja Malm, Mikko Hiltunen, , Evan Z. Macosko

The paper identifies a transient hyperactive neuronal state in early Alzheimer's disease using single-nucleus transcriptomics from living patients.

bioRxiv · Jun 3, 2023 · PreprintGenomics

Single Cell Sequencing Reveals Glial Specific Responses to Tissue Processing & Enzymatic Dissociation in Mice and Humans

Samuel E. Marsh, Alec J. Walker, Tushar Kamath, Lasse Dissing‐Olesen, Timothy R. Hammond, Yvanka de Soysa, Adam M. H. Young, Sarah Murphy, Abdulraouf Abdulraouf, Naeem M. Nadaf, Connor Dufort, Alicia C. Walker, Liliana E. Lucca, Velina Kozareva, Charles R. Vanderburg, , Beth Stevens

The paper shows enzymatic dissociation causes gene expression changes in microglia and proposes a protocol to reduce these artifacts in scRNA-seq.

Nature Neuroscience · Mar 1, 2022Peer-reviewedNeuroscience

Complex cell-state changes revealed by single cell RNA sequencing of 76,149 microglia throughout the mouse lifespan and in the injured brain

Timothy R. Hammond, Connor Dufort, Lasse Dissing‐Olesen, Stefanie Giera, Adam M. H. Young, Alec Wysoker, Alec J. Walker, Frederick W. Gergits, Michael Segel, James C. Nemesh, Samuel E. Marsh, Arpiar B. Saunders, Evan Z. Macosko, Florent Ginhoux, Jinmiao Chen, , Beth Stevens

This study identifies nine distinct microglial states in mice across lifespan and after injury using single-cell RNA sequencing, revealing persistent and age-related changes.

Immunity · Nov 21, 2018Peer-reviewedNeuroscience