Biology subjects

Lund, H.

Publications and source records attributed to Lund, H..

7 recordsLinked to original sources

bioRxiv2025

Neutrophil-neuronal crosstalk drives arthritis-induced pain

Pain in rheumatoid arthritis (RA) often persists despite effective control of inflammation, suggesting distinct mechanisms driving nociception. In both patients and animal models, pain severity does not strongly correlate with the degree of inflammation1,2. Sensory neurons, with cell bodies located in the dorsal root ganglia (DRG), innervate peripheral tissues, including joints, and transmit pain signals to the central nervous system. Crosstalk between sensory neurons and immune cells occurs at all of these sites. While sensory neurons can be directly activated by immune mediators, it remains unclear whether pain-like behaviour in antibody-induced arthritis models arises independently of immune cell activity, or which immune cell populations and mediators are required to activate pronociceptive mechanisms. Through temporal profiling of the CAIA joint-DRG transcriptomic axis, we identified SEMA4D and OSM signalling as candidate molecular mediators of neutrophil-neuron communication and neuronal sprouting. The joint-DRG atlas also revealed persistent changes in the fibroblast-immune cellular composition of the joint, along with molecular changes in DRG neurons. We showed that mechanical and cold hypersensitivity, as well as sprouting of CGRP+ nociceptive fibers in synovial tissue of mice with collagen antibody-induced arthritis (CAIA), require neutrophils but not macrophages. Analysis of publicly available datasets showed that neutrophils from the synovium of RA patients express high levels of SEMA4D and OSM, and corresponding expression of their receptors, PLEXINB1 and OSMR, in human DRG neurons, underscoring the translational relevance of this axis. Both murine and human-derived DRG neurons sprout in response to OSM. Our findings demonstrate that neutrophils produce molecules that act as cues for nociceptor sensitization and structural remodelling. Targeting these molecules could improve the efficacy of RA treatments by reducing pain while simultaneously preventing disease progression.

immunology↗

bioRxiv2025

Anoctamin-2-specific T Cells Link Epstein-Barr Virus to Multiple Sclerosis

Multiple sclerosis (MS) occurs when the central nervous system (CNS) is damaged by misguided adaptive immune responses, likely caused by a combination of environmental factors in genetically susceptible individuals. A known prerequisite for disease is Epstein-Barr virus (EBV) infection, and previous studies have demonstrated elevated Epstein-Barr virus nuclear antigen 1 (EBNA1) antibodies which cross-react with the calcium-activated chloride channel anoctamin-2 (ANO2) in persons with MS (pwMS). ANO2-reactive antibodies have been associated with greater neuroaxonal damage in MS, although their exact effector function is still uncertain. Here, we demonstrate that ANO2 is also the target of IFN{gamma}-producing CD4+ T cells, which are more frequent in untreated and natalizumab-treated pwMS compared to control individuals. Immunisation of SJL/J mice with either ANO2 or EBNA1 elicited cross-reactive CD4+ T cell and antibody responses in vivo. Pre-immunisation of young mice with ANO2 worsened proteolipid protein (PLP)-induced experimental autoimmune encephalomyelitis (EAE), which in older mice included atypical clinical phenotype, immune infiltration into the brain and reduced survival. EAE exacerbation was recapitulated with the adoptive co-transfer of ANO2 and myelin antigen-specific CD4+ T cells, and ANO2-specific T cells alone could induce the cell death of ANO2-expressing glial cells in vitro. T cell clones with cross-reactivity to both EBNA1 and ANO2 antigens could be isolated from natalizumab-treated pwMS. Single cell sequencing of EBNA1 and ANO2-specific T cell receptors (TCR) from four pwMS revealed a significant overlap between their antigen-specific expanded TCR repertoires within donors and transcriptomic analysis showed cross-reactive T cells to have predominantly activated and cytotoxic phenotypes. In summary, we report the first mechanistic evidence that EBNA1 CD4+ T cells can target the MS-associated autoantigen ANO2, thereby establishing a link between EBV infection and development of autoimmune neuroinflammatory disease.

immunology↗

bioRxiv2025

A novel method to sort and enrich sensory neurons

Peripheral sensory neurons, residing in the dorsal root ganglia (DRG), relay sensory information from the periphery to the central nervous system. Although single-cell transcriptomic studies have identified over 20 distinct sensory neuron subtypes, functional analysis and assessment of subtype-specific pathological changes remain difficult. Effective isolation and enrichment of sensory neurons are challenging yet essential for functional studies. Therefore, we used single-cell transcriptomic data from DRG to identify a panel of neuronal surface markers, including Nrxn2 and Pirt. Using these markers, we developed a fluorescence-activated cell sorting (FACS) panel for neuronal enrichment and analysis that does not rely on transgenic mouse strains and can be broadly applied. The panel was validated by microscopy and single-cell RNA (scRNA) sequencing, which also revealed broad representation of neuronal subtypes. Expression of these markers in human DRG underscores the translational value of this isolation method for sensory and pain studies. Overall, this study provides a valuable tool for isolating DRG neurons, advancing research on sensory neuron function and pain biology, and facilitating neuroimmune studies.

neuroscience↗

bioRxiv2024

Regionalized cell and gene signatures govern oesophageal epithelial homeostasis

Regionalized disease prevalence is a common feature of the gastrointestinal tract. Herein, we employed regionally resolved Smart-seq3 single-cell sequencing, generating a comprehensive cell atlas of the adult mouse oesophagus. Characterizing the oesophageal axis, we unveil non-uniform distribution of epithelial basal cells, fibroblasts and immune cells. In addition, we reveal a position-dependent, but cell subpopulation-independent, transcriptional signature, collectively generating a regionalized oesophageal landscape. Combining in vivo models with organoid co-cultures, we demonstrate that proximal and distal basal progenitor cell states are functionally distinct. We find that proximal fibroblasts are more permissive for organoid growth compared to distal fibroblasts and that the immune cell profile is regionalized in two dimensions, where proximal-distal and epithelial-stromal gradients impact epithelial maintenance. Finally, we predict and verify how WNT-, BMP-, IGF-and NRG-signalling are differentially engaged along the oesophageal axis. We establish a cellular and transcriptional framework for understanding oesophageal regionalization, providing a functional basis for epithelial disease susceptibility.

cell biology↗

bioRxiv2023

Disrupting microglial TGF-β signaling triggers region-specific pathology in the spinal cord

Transforming growth factor-{beta} (TGF-{beta}) signaling is critical for microglial maturation during development and the maintenance of microglial homeostasis in adulthood. It remains unclear whether regional susceptibilities to the loss of TGF-{beta} signaling in microglia also exist, and the contributing factors have yet to be identified. We find that deletion of Tgfbr2 on microglia leads to microglial activation and demyelination in mouse spinal cords, primarily in the dorsal column (DC). Tgfbr2-deficient microglia exhibit distinct transcriptomic changes, and those sorted from the DC display a more proinflammatory profile compared to those from the ventral column (VC) and grey matter (GM). Single nucleus RNA sequencing (snRNA-seq) of the spinal cord uncovers a microglial subtype that emerges exclusively following Tgfbr2 deletion (termed TGF{beta} signaling-suppressed microglia, TSM), exhibiting high expression of Mmp12, Gpnmb, Lgals3, Mgll, and Alcam, predominantly located in the DC. Phenotypically, disruption of microglial TGF-{beta} signaling results in behavioral deficits that are more severe in female and older mice, whereas young male mice are less affected. Mechanistically, we reveal a significantly higher level of TGF-{beta}1/TGFBR2 in the spinal cords of normal older mice compared to the young mice, with the DC region richer in genes of the TGF-{beta} signaling pathway than the VC and GM regions. This indicates that older mice and the DC region require more TGF{beta}1 to maintain tissue homeostasis and, reciprocally, are more responsive and sensitive to the disruption of TGF-{beta} signaling in microglia. Herein, we report a demyelinating disease with region-specificity and its susceptibility to the loss of microglial TGF-{beta} signaling with gender and age differences. Our findings contribute valuable information to our understanding of the importance of microglia in regulating myelin health, especially during the aging process.

neuroscience↗

bioRxiv2023

A network of CD163+ macrophages monitors enhanced permeability at the blood-dorsal root ganglion barrier

In dorsal root ganglia (DRG), macrophages reside in close proximity to sensory neurons, and their functions have largely been explored in the context of pain, nerve injury and repair. In this study, however, we discovered that the majority of macrophages in DRGs are in direct contact with the vasculature where they constantly monitor the circulation, efficiently phagocytosing proteins and macromolecules from the blood. Characterization of the DRG endothelium revealed a specialized vascular network spanning the arteriovenous axis, which gradually transformed from a barrier type endothelium in arteries to a highly permeable endothelium in veins. Macrophage phagocytosis spatially aligned with peak endothelial permeability and we identified caveolar transcytosis as a mechanism regulating endothelial permeability. Profiling of the DRG immune landscape revealed two subsets of perivascular macrophages with distinct transcriptome, turnover and function. CD163 expressing macrophages self-maintained locally, specifically participated in vasculature monitoring, displayed distinct responses during peripheral inflammation and were conserved in mouse and Man. Our work provides a molecular explanation for the permeability of the blood-DRG barrier and identifies an unappreciated role of macrophages as integral components of the DRG-neurovascular unit.

immunology↗

bioRxiv2021

Nanoengineered DNA origami with repurposed TOP1 inhibitors targeting myeloid cells for the mitigation of neuroinflammation

Targeting myeloid cells, especially microglia, for the treatment of neuroinflammatory diseases such as multiple sclerosis (MS), is underappreciated. Here, we screened a library of compounds and identified the topoisomerase 1 (TOP1) inhibitor camptothecin (CPT) as a promising drug candidate for microglial modulation. CPT and its FDA-approved analog topotecan (TPT) inhibited inflammatory responses in microglia and macrophages, and ameliorated neuroinflammation in mice. Transcriptomic analysis of sorted microglia revealed an altered transcriptional phenotype following TPT treatment, with Ikzf1 identified as a potential target. Importantly, TOP1 expression was found elevated in several neuroinflammatory conditions, including human MS brains. To achieve targeted delivery to myeloid cells we designed a nanosystem using DNA origami and loaded TPT into it (TopoGami). TopoGami also significantly suppressed the inflammatory response in microglia and mitigated disease progression in MS-like mice. Our findings suggest that TOP1 inhibition represents a therapeutic strategy for neuroinflammatory diseases, and the proposed nanosystem may foster future research and drug development with a demand to target myeloid cells.

immunology↗