Biology subjects

Kuhn, N. F.

Publications and source records attributed to Kuhn, N. F..

5 recordsLinked to original sources

bioRxiv2025

Transient Dietary Changes Modulate Inflammatory Disease Trajectory in the Lean State

Obesity potently alters immune responses across various inflammatory contexts1-7. However, it is unclear whether a transient high-fat diet (HFD) can affect immune function despite minimal effects on body weight. Here, we demonstrate that a short-term HFD regimen significantly exacerbates disease severity in a model of experimental psoriasis, comparable to what is observed in obese mice on long-term HFD. We find that a critical 4-day window of HFD coinciding with disease onset is sufficient to overactivate the immune response, leading to worsened disease outcomes. Mechanistically, we identify the CD4+ T cell compartment as an essential mediator of HFD-induced disease severity. Within the compartment, we functionally validate that disease exacerbation is driven by increased differentiation of a pathogenic population of T helper 17 (TH17) cells8 expressing IL1R1 (interleukin-1 receptor, type I)9, which is triggered by localized activation of the NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome10. This brief window of HFD at disease onset leads to immune-dependent sensitization, as disease severity is increased upon a subsequent flare, despite complete recovery and under a low-fat diet (LFD) regimen. Our data indicate that transient dietary changes during the initial stages of an inflammatory event can rewire the immune milieu, profoundly influencing disease progression and inflammatory memory11. This phenomenon may have broad implications for conditions where obesity, and not diet itself, is considered the primary risk factor.

immunology↗

bioRxiv2024

Localized in vivo gene editing of murine cancer-associated fibroblasts

Fibroblasts play critical roles in regulating cellular relationships during tissue homeostasis, immunity, and tumor biology at multiple sites. However, tools to perturb fibroblasts at just one site in vivo are limited, restricting our understanding of how these cellular relationships develop on a local level. We optimized local gene editing of fibroblasts in multiple mouse tumor models to investigate how locally restricted fibroblast perturbations affect the cellular tumor microenvironment (TME). By knocking out surface receptors Osmr, Tgfbr2, or Il1r1 on cancer-associated fibroblasts (CAFs), we uncover that TGFBR2 signaling loss uniquely induces the emergence of a Col18a1hi CAF cell state that is distinct from previously described fibroblast states and is associated with worse survival in human PDAC patients. Further application of a local as well as combinatorial gene knockout technology in CAFs reveals a circuit in which these Col18a1hi CAFs reshape the TME by recruiting Siglec-Fhi neutrophils via Cxcl5 expression; and that the Col18a1hi CAF cell state is further dependent on TNFR1 and canonical Wnt signaling. Together, a fast, affordable, and modular engineering method is demonstrated, allowing discovery of a modified fibroblast identify, as well as the network details of a local inter-cellular circuitry in a tumor. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/603114v2_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@f375c5org.highwire.dtl.DTLVardef@1b8fad9org.highwire.dtl.DTLVardef@15cfd0aorg.highwire.dtl.DTLVardef@1e8dacc_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2023

Critical role of CD206+ macrophages in organizing anti-tumor immunity

Tumor-associated macrophages (TAMs) are frequently categorized as being M1 or M2 polarized, even as substantial data challenges this binary modeling of macrophage cell state. One molecule consistently referenced as a delineator of a putative immunosuppressive M2 state is the surface protein CD206. We thus made a novel conditional CD206 (Mrc1) knock-in mouse to specifically visualize and/or deplete CD206+ M2-like TAMs and assess their correspondence with pro-tumoral immunity. Early, but not late depletion of CD206+ macrophages and monocytes (here, Mono/Macs) led to an indirect loss of a key anti-tumor network of NK cells, conventional type I dendritic cells (cDC1) and CD8 T cells. Among myeloid cells, we found that the CD206+ TAMs are the primary producers of CXCL9, and able to differentially attract activated CD8 T cells. In contrast, a population of stress-responsive TAMs ("Hypoxic" or Spp1+) and immature monocytes, which lack CD206 expression and become prominent following early depletion, expressed markedly diminished levels of CXCL9. Those NK and CD8 T cells which enter CD206- depleted tumors express vastly reduced levels of the corresponding receptor Cxcr3, the cDC1- attracting chemokine Xcl1 and cDC1 growth factor Flt3l transcripts. Consistent with the loss of this critical network, early CD206+ TAM depletion decreased tumor control by antigen specific CD8 T cells in mice. Likewise, in humans, the CD206Replete, but not the CD206Depleted Mono/Mac gene signature correlated robustly with CD8 T cell, NK cell and stimulatory cDC1 gene signatures and transcriptomic signatures skewed towards CD206Replete Mono/Macs associated with better survival. Together, these findings negate the unqualified classification of CD206+ M2-like macrophages as immunosuppressive by illuminating contexts for their role in organizing a critical tumor-reactive archetype of immunity.

immunology↗

bioRxiv2022

Space-Time Mapping Identifies Concerted Multicellular Patterns and Gene Programs in Healing Wounds and their Conservation in Cancers

Tissue repair responses in metazoans are highly coordinated by different cell types over space and time. However, comprehensive single-cell based characterization covering this coordination is lacking. Here, we captured transcriptional states of single cells over space and time during skin wound closure, revealing choreographed gene expression profiles. We identified shared and prominent space-time patterns of cellular and gene expression enrichment: which we call multicellular movements and which spanned multiple cell types. We validated some of the discovered space-time movements using large volume imaging of cleared wounds and demonstrated the value of this analysis to predict gene products made by macrophages or fibroblasts, which activated gene programs in the opposite cell type. Finally, using two different tumor models, we tested the hypothesis that tumors are like wounds that never heal finding conserved wound healing movements in the tumor space, wherein some movements were preferentially used in one tumor versus another. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=119 SRC="FIGDIR/small/493500v2_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@12a03e3org.highwire.dtl.DTLVardef@1654966org.highwire.dtl.DTLVardef@b603c0org.highwire.dtl.DTLVardef@1b05998_HPS_FORMAT_FIGEXP M_FIG C_FIG

systems biology↗

bioRxiv2020

Global Absence and Targeting of Protective Immune States in Severe COVID-19.

While SARS-CoV-2 infection has pleiotropic and systemic effects in some patients, many others experience milder symptoms. We sought a holistic understanding of the severe/mild distinction in COVID-19 pathology, and its origins. We performed a whole-blood preserving single-cell analysis protocol to integrate contributions from all major cell types including neutrophils, monocytes, platelets, lymphocytes and the contents of serum. Patients with mild COVID-19 disease display a coordinated pattern of interferon-stimulated gene (ISG) expression across every cell population and these cells are systemically absent in patients with severe disease. Severe COVID-19 patients also paradoxically produce very high anti-SARS-CoV-2 antibody titers and have lower viral load as compared to mild disease. Examination of the serum from severe patients demonstrates that they uniquely produce antibodies with multiple patterns of specificity against interferon-stimulated cells and that those antibodies functionally block the production of the mild disease-associated ISG-expressing cells. Overzealous and auto-directed antibody responses pit the immune system against itself in many COVID-19 patients and this defines targets for immunotherapies to allow immune systems to provide viral defense. One Sentence SummaryIn severe COVID-19 patients, the immune system fails to generate cells that define mild disease; antibodies in their serum actively prevents the successful production of those cells.

immunology↗