Pedersen, E. A. | bioRxiv Science

bioRxiv2025

Cross-disease comparison of dermatomyositis and lupus skin identifies inflammatory monocytes and JAK-1 signaling as drivers of vasculopathy in dermatomyositis

Dermatomyositis (DM) is a rare yet devastating autoimmune disease characterized by inflammatory and vasculopathic changes in skin and muscle. DM and systemic lupus erythematosus (lupus) skin lesions have overlapping clinical and histopathological features, yet disparate responses to available therapeutics. DM skin disease is often relapsing and recalcitrant. To investigate DM immunopathogenesis, non-lesional skin, lesional skin, and circulating immune cells from DM patients were analyzed using single-cell RNA-sequencing. Samples were analyzed in parallel with lesional and non-lesional lupus skin, healthy control skin, and peripheral blood. We demonstrate a pervasive type I interferon (IFN) signature in DM stroma that persists in culture and is distinguished from lupus by upregulation of VEGF and IL-18 signaling in DM keratinocytes. Furthermore, endothelial cells (ECs) in lesional DM exhibit decreased proliferation that was not observed in lupus. Using cell communication networks, we identified a population of DM-specific monocytes interacting with non-proliferating DM ECs. Co-culture of monocytes from DM patients with ECs resulted in increased EC apoptosis inhibited by JAK1 blockade. JAK1 inhibition also resulted in reversal of DM-stromal and inflammatory signatures. Together, our data provide a comprehensive cross-disease characterization of lesional and non-lesional skin of DM compared to lupus and implicate monocyte-mediated EC dysfunction in DM vasculopathy and support JAK inhibition for refractory skin disease.

immunology↗

bioRxiv2023

Hacking brain development to test models of sensory coding

Animals can discriminate myriad sensory stimuli but can also generalize from learned experience. You can probably distinguish the favorite teas of your colleagues while still recognizing that all tea pales in comparison to coffee. Tradeoffs between detection, discrimination, and generalization are inherent at every layer of sensory processing. During development, specific quantitative parameters are wired into perceptual circuits and set the playing field on which plasticity mechanisms play out. A primary goal of systems neuroscience is to understand how material properties of a circuit define the logical operations-- computations--that it makes, and what good these computations are for survival. A cardinal method in biology--and the mechanism of evolution--is to change a unit or variable within a system and ask how this affects organismal function. Here, we make use of our knowledge of developmental wiring mechanisms to modify hard-wired circuit parameters in the Drosophila melanogaster mushroom body and assess the functional and behavioral consequences. By altering the number of expansion layer neurons (Kenyon cells) and their dendritic complexity, we find that input number, but not cell number, tunes odor selectivity. Simple odor discrimination performance is maintained when Kenyon cell number is reduced and augmented by Kenyon cell expansion.

neuroscience↗