Biomedical subjects

Brian D Brown

Publications and source records attributed to Brian D Brown.

5 recordsLinked to original sources

PubMed2026

A serpin-myeloid axis in pancreatic cancer heterogeneity and immune evasion.

Pancreatic ductal carcinoma (PDAC) is characterized by a highly immunosuppressive, extracellular matrix-rich microenvironment, yet tumours display marked heterogeneity1-4. This raises the question of whether immune resistance is a global tumour property or is organized within spatially restricted niches. Here, using Perturb-map spatial functional genomics, we determine how different genes shape the growth and cellular environments of PDAC clones across space and time. This analysis revealed early gene-driven remodelling of local immune neighbourhoods preceding late-stage spatial clonal dominance. We identify SERPINE1 (encoding plasminogen activator inhibitor 1 (PAI1)) and SERPINB2 (encoding PAI2) as dominant regulators of tumour microenvironment control and immune evasion. These serpins promote stabilization of fibrin-rich extracellular matrix niches that spatially retain and programme macrophages towards immunosuppressive states while excluding cytotoxic T cells. Loss of Serpine1 or Serpinb2, or pharmacological inhibition of PAI1 or CD18, improves tumour control in mice and synergizes with anti-PD-1. Multimodal spatial analysis of patient tumours revealed that immunosuppressive niches form around rare SERPINB2- and SERPINE1-expressing PDAC subpopulations, dominated by SPP1+/MARCO+ macrophages. These findings identify cancer-derived SERPINE1 and SERPINB2 as local spatial organizers of immune suppression, linking tumour-intrinsic heterogeneity to local microenvironmental control and immunotherapy resistance in PDAC.

Journal Article↗

PubMed2026

Emerging Principles in Spatial Functional Genomics.

Spatial transcriptomic and proteomic atlases have enabled mapping of gene programs within intact tissues, but these measurements remain largely descriptive and do not define the mechanisms controlling tissue biology. Pooled CRISPR screening provides scalable causal interrogation of gene function but remains largely confined to dissociated systems that lack spatial context. In vivo spatial functional genomics (SFG) bridges these approaches by integrating genetic perturbations with in situ transcriptomic and proteomic readouts to measure gene function within intact tissue ecosystems. By preserving spatial organization, SFG enables interpretation of perturbations through effects on cell-cell interactions, diffusible signals, multicellular niches, and tissue architecture. Here, we outline key design axes of SFG: perturbation strategy, barcoding strategy, and phenotypic readout. We discuss computational challenges, including spatial autocorrelation, neighborhood dependence, and context-aware null modeling, and highlight how SFG reveals non-cell-autonomous, architecture-dependent mechanisms of gene function, advancing toward predictive models of tissue organization and gene function.

Genomics↗

PubMed2026

Dendritic cells control tertiary lymphoid structure development and maintenance in cancer.

Tertiary lymphoid structures (TLSs) are associated with immunotherapy response, yet the mechanisms controlling their formation and maintenance remain unclear. Using spatial transcriptomics and multiplex imaging across human tumors, we found that CCR7+ mature dendritic cells (DCs) accumulate in TLSs. In a mouse non-small cell lung cancer model that forms mature TLSs, we show that early TLS development requires interferon-γ (IFN-γ)-driven type 1 conventional dendritic cell (cDC1) maturation, migration to tumor-draining lymph nodes (tdLNs), and T cell recruitment. As tumors progress, TLSs persist independently of tdLN T cell egress, coinciding with cDC1 accumulation within intratumoral CCL19 stromal hubs. There, cDC1-major histocompatibility complex class 1 (MHC-I) and -MHC-II concomitant antigen presentation, along with CD40 signaling, sustain TLS, T follicular helper (TFH) cell pool, germinal centers, and tumor-specific immunoglobulin G (IgG). These findings highlight local mature cDC1s as key TLS orchestrators and potential targets to enhance antitumor TLS function.

Animals↗

PubMed2026

mRNA vaccine immunity is enhanced by hepatocyte detargeting and not dependent on dendritic cell expression.

Proteins encoded by mRNA vaccines can be expressed by a diversity of transfected cell types but how cell-type-specific expression influences immunity is poorly understood. To investigate this, we incorporated synthetic microRNA target sites (miRT) into lipid nanoparticle (LNP)-delivered mRNA vaccines to silence mRNA expression specifically in professional antigen-presenting cells (pAPCs), hepatocytes or myocytes. We found that mRNA expression in pAPCs was dispensable for priming antigen-specific T cells, whereas mRNA expression in myocytes induced similar or stronger immune responses, including for SARS-CoV-2, suggesting that antigen cross-presentation or cross-dressing may be more impactful than direct mRNA expression in pAPCs. In contrast, mRNA expression in hepatocytes suppressed the antigen-specific T cell response, partly through PD1/PDL1. In mice bearing tumor-associated antigen (TAA)-expressing lymphoma cells, miRT-mediated hepatocyte-silenced TAA mRNA vaccine enhanced immune response and reduced tumor burden. Thus, non-pAPC expression shapes immunity to mRNA-encoded protein and inclusion of miRTs can boost or blunt mRNA-LNP immunogenicity.

Journal Article↗

PubMed2024

Accelerating diabetic wound healing by ROS-scavenging lipid nanoparticle-mRNA formulation.

Current treatment options for diabetic wounds face challenges due to low efficacy, as well as potential side effects and the necessity for repetitive treatments. To address these issues, we report a formulation utilizing trisulfide-derived lipid nanoparticle (TS LNP)-mRNA therapy to accelerate diabetic wound healing by repairing and reprogramming the microenvironment of the wounds. A library of reactive oxygen species (ROS)-responsive TS LNPs was designed and developed to encapsulate interleukin-4 (IL4) mRNA. TS2-IL4 LNP-mRNA effectively scavenges excess ROS at the wound site and induces the expression of IL4 in macrophages, promoting the polarization from the proinflammatory M1 to the anti-inflammatory M2 phenotype at the wound site. In a diabetic wound model of db/db mice, treatment with this formulation significantly accelerates wound healing by enhancing the formation of an intact epidermis, angiogenesis, and myofibroblasts. Overall, this TS LNP-mRNA platform not only provides a safe, effective, and convenient therapeutic strategy for diabetic wound healing but also holds great potential for clinical translation in both acute and chronic wound care.

Wound Healing↗