Biology subjects

Harter, M. F.

Publications and source records attributed to Harter, M. F..

3 recordsLinked to original sources

bioRxiv2025

Modeling host-microbe interactions in immunocompetent engineered human gut tissues

The intestinal mucosal barrier contains microbial organisms within the lumen while preserving the ability to absorb nutrients. Dietary, microbial, and other exposures shaped human barrier evolution and continue to impact disease susceptibility. Here, we established engineered barrier models of the human small intestine and colon composed of a multilineage epithelium, mucus layer, accessible microbial compartment and autologous tissue-resident immune cells. The epithelium has crypt- and villus-like topological domains, with stem cells differentiating into absorptive and secretory lineages with region-specific identities. Secreted mucins accumulate apically, forming a dense mucus layer separating the epithelium from colonizing commensal and pathogenic bacteria. Intestinal memory T cells integrate into and interact with the epithelium. We use the engineered intestinal tissues to identify an epithelial gene regulatory network underlying response to Salmonella Typhimurium infection, and uncover epithelial-immune-pathogen crosstalk coordinating cytokine release and epithelial damage. Overall, this work allows for the modular integration of epithelial, microbial, and immune compartments providing a versatile system for studying human intestinal physiology and pathologies.

bioengineering↗

bioRxiv2025

High-throughput histopathology for complex in vitro models

Human complex in vitro models (CIVMs) have demonstrated remarkable potential to study tissue development, physiology and disease at high-throughput. To effectively employ these miniaturized systems in translational preclinical research, their in-depth benchmarking is pivotal. Histology has been the core of tissue characterization for centuries and the foundation of spatial phenotyping. However, standard histology workflows are inherently low-throughput and centered on large tissue pieces. This does not match the high sample volumes and small sample sizes in CIVM research. Here, we introduce a holistic histo-workflow, utilizing 3D-printed histomolds that facilitate co-planar embedding of CIVMs at high-throughput, resulting in up to 48 samples in one section. We developed a variety of model-specific histomold designs that enable spatially controlled histological sectioning and downstream analyses. We describe these workflows, including mold generation, highplex staining and image analysis, and exemplify their application to histological analyses of various CIVMs. Altogether, the histomolds introduced here afford opportunities for CIVM processing and analysis, while significantly reducing labor and reagent resources, thereby democratizing high-throughput CIVM in histopathology.

pathology↗

bioRxiv2023

Human intestinal organoids with an autologoustissue-resident immune compartment

The intimate relationship between the epithelium and the immune system is crucial for maintaining tissue homeostasis, with perturbations in epithelial-immune interactions linked to autoimmune disease and cancer. Whereas stem cell-derived organoids are powerful models of tissue-specific epithelial function, these structures lack tissue-resident immune cells that are essential for capturing organ-level processes. We describe human intestinal immuno-organoids (IIOs), formed through self-organization of epithelial organoids and autologous tissue-resident lymphocytes (TRMs), a portion of which integrate within the IIO epithelium and survey the barrier. IIO formation was driven by TRM migration and interaction with epithelial cells, as orchestrated by TRM-enriched transcriptomic programs governing cell motility and epithelial inspection. We combined IIOs and single-cell transcriptomics to investigate intestinal inflammation triggered by cancer-targeting biologics in patients, and found that the system recapitulates clinical outcomes and the underlying cellular mechanisms. Inflammation was associated with the emergence of an activated population of CD8+ T cells, which progressively acquired intraepithelial and cytotoxic features. The appearance of this effector population was preceded and likely mediated by a Th1-like CD4+ population, which initially displayed a cytokine-producing character and subsequently became cytotoxic itself. A system amenable to direct perturbation and interrogation, IIOs allowed us to identify the Rho pathway as a novel target for mitigating immunotherapy-associated intestinal inflammation. Given that they recapitulate both the phenotypic outcomes and the underlying inter-lineage immune interactions, IIOs can be used to broadly study tissue-resident immune responses in the context of tumorigenesis, infectious and autoimmune diseases.

immunology↗