Biology subjects

Gudjonsson, J. E.

Publications and source records attributed to Gudjonsson, J. E..

At least 19 recordsLinked to original sources

bioRxiv2026

IFN-κ directs antiviral immunity in human skin

Inducible expression of type I IFNs is a well-established host innate defense mechanism to limit virus infection. Yet, many viruses have evolved strategies to suppress the induction of these cytokines to enhance replication, spread, and transmission between hosts. Whether additional antiviral mechanisms protect against infection when inducible responses are compromised is not well understood. Here, we demonstrate that human keratinocytes preemptively protect the skin against virus infection through constitutive production of IFN-kappa (IFN-{kappa}), a poorly studied type I IFN family member. We find that constitutive IFNK expression protects keratinocytes against skin tropic RNA and DNA viruses, including vesicular stomatitis virus (VSV) and herpes simplex virus-1 (HSV-1). Using a human skin organoid model, we further demonstrate that keratinocyte-derived IFN-{kappa} establishes an antiviral state in dermal fibroblasts. Genetic and chemical analysis of the type I IFN receptor (IFNAR) signaling pathway in monocultured keratinocytes and skin organoids revealed that distinct pathways control VSV and HSV-1 replication. While canonical JAK-STAT signaling provided protection against VSV, HSV-1 infection was controlled through a JAK-STAT-independent mechanism. Using transcriptomic analysis, we further identified an IFN-{kappa}-dependent gene signature in keratinocytes that is not similarly driven by other type I IFNs. Together, this work establishes constitutive IFN-{kappa} production by keratinocytes as a broadly antiviral tissue autonomous defense mechanism.

immunology↗

bioRxiv2026

Genome-scale perturbation signatures from primary human CD4+ T cells improve genetics-based prioritization of immune drug targets

While human genetic evidence improves drug program success, target selection largely relies on associational features. Even functional features are mainly observational, capturing disease associations rather than the consequence of perturbing genes in the disease-relevant human cell type. To move beyond association, we present IGNITE (Immune Genomics and fuNctional Integration for Target Enrichment), a framework that prioritizes immune drug targets by integrating human genetic priors with features from genome-scale perturb-seq in 22 million primary human CD4+ T cells and polarized T-helper subset differential expression. IGNITE is a semi-supervised machine learning model that applies positive-unlabeled learning to approved immune targets, then ranks 19,502 protein-coding genes to prioritize new candidates. In 727 in-trial genes held out from training, functional genomics increased target enrichment among the top 50 nominations from 2.7- to 4.8-fold for immune trial targets at any phase, and from 4.5- to 5.9-fold for targets in Phase III. These performance gains were immune-specific, as IGNITE outperformed genetic comparators on predicting immune-exclusive targets but not on cardiac-exclusive targets. Using temporal validation with labels frozen in 2014, IGNITE outperformed the genetics-only model in ranking 134 genes that subsequently entered immune trials. The functional genomics layer also surfaced two novel, pharmacologically tractable candidates, ELOVL6 and RUVBL1, elevating their rankings from outside the top 1,000 into the top 50. These findings highlight that perturbational signatures in the disease-relevant human cell type harbor target-relevant signals beyond human genetics, offering a generalizable route to indication-specific prioritization as perturbation atlases expand. Full IGNITE scores are publicly available at https://ignite.eecs.umich.edu/

bioinformatics↗

bioRxiv2026

Multiomic Analysis Reveals an IFN-driven Cellular Landscape Effectively Targeted by Ruxolitinib in Hailey-Hailey Disease

Hailey-Hailey disease (HHD) is a rare autosomal dominant genodermatosis characterized by skin blistering and erosions in intertriginous regions, frequently complicated by secondary infections leading to substantial impairment in quality of life. No targeted mechanism-based therapies are currently available. Here, we applied a multiomics approach to define the molecular and cellular landscape of HHD. Bulk transcriptomics and proteomics uncovered a striking interferon (IFN) signature in HHD skin lesions. Single cell and spatial transcriptomics analyses revealed inflammatory niches, where immune, epithelial, vascular and stromal cells create a multi-compartment IFN-driven signaling network, that sustains a feed-forward amplification loop essential for chronic inflammation. Crucially, in nine patients with refractory HHD, topical treatment with the JAK1/2 inhibitor ruxolitinib led to rapid and durable re-epithelialization with drastic reduction in pain, itching, oozing and skin inflammation, significantly improving patient quality of life. Collectively, our findings identify IFN signaling as a key pathogenic driver in HHD and support topical JAK inhibition as an effective therapy, redefining the standard of care for individuals living with HHD.

pathology↗

bioRxiv2026

Hailey-Hailey disease models identify synergistic therapeutic effects of MEK and ROCK inhibition

Hailey-Hailey disease (HHD) is a genetic skin blistering disorder lacking approved treatments despite linkage to ATP2C1 variants 25 years ago. Since knockout mice did not replicate HHD, we ablated ATP2C1 in human keratinocytes or chemically inhibited its encoded Golgi calcium pump SPCA1. In organotypic epidermis, SPCA1 deficiency or inhibition reproduced HHD pathology, disrupting desmosomal cadherins and severing cell-cell junctions, termed acantholysis. RNA sequencing of heterozygous cells identified dysregulation of actin and Rho GTPases along with EGF receptor signaling as potential pathogenic drivers. Accordingly, SPCA1-depleted organotypic epidermis and HHD biopsies exhibited cortical actin disorganization and hyper-phosphorylation of the Rho kinase (ROCK) target, myosin light chain. Rho activation was sufficient to induce acantholysis, while ROCK inhibition partially restored heterozygous keratinocyte cohesion. A fluorescent biosensor demonstrated ERK hyper-activation in heterozygous cells along with desmosomal cadherin mis-localization. Importantly, treating SPCA1-deficient keratinocyte sheets with MEK and ROCK inhibitors together fully restored their integrity. Our results show HHD blistering is driven by desmosome and cortical actin dysfunction that was mitigated by targeting MEK and ROCK with repurposed drugs, offering a viable treatment strategy. Moreover, our model provides a blueprint for replicating genetic epidermal disorders to delineate pathogenic mechanisms and vet therapeutics for other orphan skin diseases. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=199 SRC="FIGDIR/small/726679v1_ufig1.gif" ALT="Figure 1"> View larger version (57K): org.highwire.dtl.DTLVardef@b2de6aorg.highwire.dtl.DTLVardef@128411borg.highwire.dtl.DTLVardef@1ca760forg.highwire.dtl.DTLVardef@10cd6c7_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2026

Disease-specific differences in particulate matter handling drive pathogenic responses in human derived nasal epithelial cells

BackgroundParticulate matter (PM) exposure is associated with increased risk and exacerbation of chronic rhinosinusitis (CRS), yet underlying mechanisms remain poorly understood. ObjectiveTo define the epithelial mechanisms by which PM exposure promotes and exacerbates CRS, with a focus on epithelial remodeling, inflammation, barrier dysfunction, and cellular uptake of PM. MethodsHuman nasal epithelial cells obtained from ethmoid tissue of CRS (n = 5) and control donors (n = 4) were cultured at an air-liquid interface and exposed to PM. Single-cell RNA sequencing was performed to characterize PM-induced cellular and transcriptional changes. Protein expression, epithelial barrier integrity, cell death, and intracellular PM uptake were evaluated using biochemical, imaging, and ultrastructural approaches. ResultsUnsupervised clustering identified seven epithelial cell populations. Gene set analysis revealed baseline enrichment of inflammatory and keratinization pathways and reduced ciliogenesis in CRS compared with controls. Although PM induced inflammation and squamous differentiation in controls, the pathogenic responses were significantly amplified in CRS, including uniquely enhanced IL-1 signaling. Transcriptional changes were validated by ELISA, transepithelial electrical resistance, and immunofluorescence, demonstrating increased inflammation, epithelial barrier disruption, and cell death following PM exposure. Transmission electron microscopy revealed increased intracellular PM within membrane-bound organelles. Pre-treatment with an endocytosis inhibitor rescued PM-induced epithelial barrier dysfunction and inflammation. ConclusionCRS epithelium exhibits baseline dysfunction that may predispose it to environmental injury. PM exposure both induces CRS-like epithelial changes in controls and exacerbates disease-associated phenotypes. Key MessagesO_LICompared to controls, CRS nasal epithelium exhibits baseline inflammatory, keratinization, and ciliogenesis abnormalities. C_LIO_LIParticulate matter induces inflammation and squamous differentiation, while amplifying epithelial injury that is more robust in CRS epithelium compared to controls. C_LIO_LIInhibition of dynamin-dependent endocytosis rescues PM-induced epithelial barrier leakiness and inflammation, implicating intracellular particulate matter uptake in disease pathogenesis. C_LI Capsule SummaryParticulate matter induces CRS-like epithelial remodeling in controls and exacerbates inflammation and epithelial barrier dysfunction in CRS nasal epithelium, which can be rescued with endocytosis inhibition. This suggests a mechanistic link between baseline CRS vulnerability, intracellular uptake of particulate matter, and disease pathogenesis.

cell biology↗

bioRxiv2026

Disease context dictates the cellular targets of IL-17 in inflammatory skin disease

Therapeutic blockade of IL-17 and TNF can effectively treat inflammatory skin diseases such as hidradenitis suppurativa and psoriasis, yet the relative importance of the different cell types that respond to IL-17 and TNF remains unresolved. Keratinocytes are viewed as the dominant effector cells, whereas fibroblasts have recently emerged as important contributors. In mice, topical imiquimod induces IL-17- and TNF-dependent skin inflammation and is frequently used to model psoriasis. Here, we demonstrate that intradermal injection of recombinant IL-17 and TNF elicits skin inflammation with features of hidradenitis suppurativa, including a gene expression program that is distinct from psoriasis and imiquimod-induced inflammation. Single-cell transcriptomic network analysis identified dermal fibroblasts as the dominant cell communication hub in hidradenitis suppurativa and in mice injected with IL-17 and TNF. In contrast, fibroblasts and keratinocytes both show strong network involvement in psoriasis and in mice challenged with imiquimod. Cell-type-specific deletion of IL-17 receptor A in mice revealed that imiquimod-induced inflammation depends equally on IL-17 signaling in fibroblasts and keratinocytes, whereas inflammation induced by intradermal IL-17 and TNF only requires fibroblasts to recognize IL-17 and is independent of keratinocyte IL-17 sensing. Single-cell transcriptomic analysis of these conditional knockout mice further demonstrated that keratinocytes and fibroblasts activate divergent and disease-dependent transcriptional programs following activation by IL-17. Together, these findings introduce a new conceptual framework wherein IL-17 signaling is routed through distinct cellular and molecular pathways depending on disease context and establish complementary experimental systems for interrogating type 17 skin inflammation.

immunology↗

bioRxiv2026

Imbalance of Ciliary Programs Drives Fibroblast Differentiation and Fibrotic Signaling in Systemic Sclerosis

Systemic sclerosis (SSc) is a chronic fibrotic disease characterized by accumulation of activated profibrotic myofibroblasts in multiple organs. The mechanisms triggering pathogenic fibroblast to myofibroblast reprogramming in SSc, and maintaining the activated myofibroblast state, are not well known. Recent studies show that primary cilia (PC), solitary sensory organelles that integrate diverse chemical and mechanical signaling pathways, may regulate fibroblast fates. Here, using an orthogonal multimodal strategy spanning human cohorts, single-cell trajectories, and targeted perturbation models, we identify a fundamental imbalance in cilia-program dynamics as a unifying driver of fibrotic activation in SSc. Meta-analysis of skin biopsies integrating eight microarray datasets and two independent scRNA-seq cohorts, revealed a conserved 15-gene cilia signature that is altered in SSc. Single-cell trajectory mapping resolved a principal progenitor[->] secretory-like [->] myofibroblast differentiation axis, where SSc fibroblasts displayed spatially dysregulated ciliary programs that established a prolonged, disassembly-dominant "cilia-off" state. Notably, this ciliary imbalance appeared to emerge before the transition to fibrotic gene programs, positioning cilia disruption as an initiating, not secondary, event in fibroblast programming. Consistent with these transcriptomic findings, PC length was significantly reduced in SSc skin and cultured fibroblasts. Mechanistically, genetic and pharmacological perturbation studies demonstrated that cilia disruption is sufficient to drive fibrotic programs. These data establish a reciprocal regulatory framework in which shortened cilia promote sustained activation of TGF-{beta}-Hippo feed-forward signaling, driving fibroblast-to-myofibroblast transition and amplifying fibrotic responses. Together, these findings position the imbalance between ciliary assembly and disassembly as a central determinant of fibrotic fibroblast fate in SSc. Moreover, they indicate that therapeutically stabilizing primary cilia, "ciliotherapy", can reset pathological fibroblast trajectories and represents a promising antifibrotic strategy for SSc and other fibrotic conditions. TeaserDisrupted Primary Cilia Drives Pathophysiology of Systemic Sclerosis.

cell biology↗

bioRxiv2025

Semi-parametric Empirical Bayes Method for Multiplet Detection in snATAC-seq with Probabilistic Multi-omic Integration

Multiplets, formed when multiple cells are captured in a droplet, produce hybrid molecular profiles that confound single-cell analyses. Detecting multiplets in single-nucleus ATAC-seq (snATAC-seq) data is particularly challenging due to sparsity and overdispersion of chromatin accessibility measurements. We introduce SEBULA, a semi-parametric empirical Bayes model that yields well-calibrated posterior probabilities for multiplet detection, enabling principled false discovery rate control. SEBULA also integrates probabilistic evidence with complementary signals from other modalities, such as scRNA-seq. Benchmarking on simulations and seven annotated trimodal DOGMA-seq datasets demonstrates SEBULAs superior performance. The open-source software is computationally efficient.

genomics↗

bioRxiv2025

The endoplasmic reticulum autophagy receptor TEX264 drives epidermal differentiation and is dysregulated in Darier disease

Differentiating keratinocytes break down their organelles and nuclei to become the compacted cornified layers of the epidermal barrier in a poorly understood catabolic process. Live confocal imaging of stratified human organotypic epidermis revealed endoplasmic reticulum (ER) fragmentation and lysosomal engulfment in the cornifying layers, where we found up-regulation of TEX264, a receptor that mediates selective autophagy of the ER (reticulophagy). TEX264 expression was increased by ER stress, which caused precocious cornification of organotypic epidermis. In undifferentiated keratinocytes, ectopic TEX264 was sufficient to fragment the ER, while in highly differentiated keratinocytes, it accelerated ER elimination and induced nuclear shrinkage; these effects were abolished by mutating the LC3 interacting region required for its autophagic function. Knockout of TEX264 or inhibiting its activation disrupted maturation of organotypic cultures, pointing to a critical role for reticulophagy in cornification. Finally, in patient biopsies and an organotypic model of Darier disease, a genetic cornification disorder linked to ER dysfunction, we found increased TEX264 in areas of premature cornification (dyskeratosis). Our results identified TEX264 as a key driver of epidermal differentiation and led us to propose a novel model of cornification in which keratinocytes activate selective autophagy receptors to orchestrate orderly organelle elimination during cutaneous barrier formation. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=66 SRC="FIGDIR/small/668774v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@46f7a6org.highwire.dtl.DTLVardef@12cd441org.highwire.dtl.DTLVardef@23327aorg.highwire.dtl.DTLVardef@c6e9b5_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2025

VGLL3-centered network connects placental, vascular, and immune defects in preeclampsia

Preeclampsia affects approximately 1 in 10 pregnancies, leading to severe complications and long-term health risks for both mother and offspring. While the etiology remains unclear, preeclampsia has been linked to both autoimmunity and the timing of menarche. Through human single-cell and spatial analyses, coupled with in vitro, in vivo, and ex vivo models, we demonstrate that VGLL3, a transcription co-regulator in the Hippo pathway, is upregulated in preeclamptic placentas. VGLL3 promotes immune activation, impairs trophoblast differentiation, and induces endothelial dysfunction, all of which contribute to pregnancy-related hypertension, fetal growth restriction, and offspring mortality. Our data reveal that VGLL3 acts upstream of preeclampsia-associated processes, including the production of sFLT1, a key biomarker of the disease. Notably, targeting VGLL3--either by genetic deletion in mouse placentas or through therapeutic inhibition in human placentas--protects against preeclampsia and alleviates disease pathology. These findings position VGLL3 as a promising novel therapeutic target for preeclampsia.

immunology↗

bioRxiv2025

A Transcriptomic Atlas of Healthy Human Skin Links Regional Identity to Inflammatory Disease.

Human skin is not a uniform organ but a mosaic of anatomically distinct niches, with each site finely tuned to unique environmental demands and immune pressures. Yet, the molecular determinants that define these regional identities and their relationship to site-specific vulnerability to inflammatory disease remain poorly understood. Here, we generate a high-resolution single-cell atlas of human skin, profiling 274,834 cells from 96 healthy samples across 7 anatomically distinct sites (acral, arm, axilla, back, face, leg and scalp). Our analysis reveals striking region-specific transcriptional and cellular networks, uncovering how local immune-stromal crosstalk governs tissue homeostasis and underpins anatomical susceptibility to distinct inflammatory diseases such as such as systemic lupus erythematosus (SLE), atopic dermatitis (AD), and psoriasis. These findings illuminate the tissue-intrinsic foundations of regional immune identity and provide a blueprint/resource for the development of precision therapies tailored to the distinct immunological microenvironments of specific anatomical skin sites.

systems biology↗

bioRxiv2025

Seq-Scope-eXpanded: Spatial Omics Beyond Optical Resolution

Sequencing-based spatial transcriptomics (sST) enables transcriptome-wide gene expression mapping but falls short of reaching the optical resolution (200-300 nm) of imaging-based methods. Here, we present Seq-Scope-X (Seq-Scope-eXpanded), which empowers submicrometer-resolution Seq-Scope with tissue expansion to surpass this limitation. By physically enlarging tissues, Seq-Scope-X minimizes transcript diffusion effects and increases spatial feature density by an additional order of magnitude. In liver tissue, this approach resolves nuclear and cytoplasmic compartments in nearly every single cell, uncovering widespread differences between nuclear and cytoplasmic transcriptome patterns. Independently confirmed by imaging-based methods, these results suggest that individual hepatocytes can dynamically switch their metabolic roles. Seq-Scope-X is also applicable to non-hepatic tissues such as brain and colon, and can be modified to perform spatial proteomic analysis, simultaneously profiling hundreds of barcode-tagged antibody stains at microscopic resolutions in mouse spleens and human tonsils. These findings establish Seq-Scope-X as a transformative tool for ultra-high-resolution whole-transcriptome and proteome profiling, offering unparalleled spatial precision and advancing our understanding of cellular architecture, function, and disease mechanisms.

genomics↗

bioRxiv2024

Pemphigus vulgaris autoantibodies induce an ER stress response

Desmosomes are intercellular junctions that mediate cell-cell adhesion and are essential for maintaining tissue integrity. Pemphigus vulgaris (PV) is an autoimmune epidermal blistering disease caused by autoantibodies (IgG) targeting desmoglein 3 (Dsg3), a desmosomal cadherin. PV autoantibodies cause desmosome disassembly and loss of cell-cell adhesion, but the molecular signaling pathways that regulate these processes are not fully understood. Using high- resolution time-lapse imaging of live keratinocytes, we found that ER tubules make frequent and persistent contacts with internalizing Dsg3 puncta in keratinocytes treated with PV patient IgG. Biochemical experiments demonstrated that PV IgG activated ER stress signaling pathways, including both IRE1 and PERK pathways, in cultured keratinocytes. Further, ER stress transcripts were upregulated in PV patient skin. Pharmacological inhibition of ER stress protected against PV IgG-induced desmosome disruption and loss of keratinocyte cell-cell adhesion, suggesting that ER stress may be an important pathomechanism and therapeutically targetable pathway for PV treatment. These data support a model in which desmosome adhesion is integrated with ER function to serve as a cell adhesion stress sensor that is activated in blistering skin disease.

cell biology↗

bioRxiv2024

Positionally distinct interferon stimulated dermal immune acting fibroblasts promote neutrophil recruitment in Sweet's syndrome

Sweets syndrome is a poorly understood inflammatory skin disease characterized by neutrophil infiltration to the dermis. Single-nucleus and bulk transcriptomics of archival clinical samples of Sweets syndrome revealed a prominent interferon signature in Sweets syndrome skin that was reduced in tissue from other neutrophilic dermatoses. This signature was observed in different subsets of cells, including fibroblasts that expressed interferon-induced genes. Functionally, this response was supported by analysis of cultured primary human dermal fibroblasts that were observed to highly express neutrophil chemokines in response to activation by type I interferon. Furthermore, single-molecule resolution spatial transcriptomics of skin in Sweets syndrome identified positionally distinct immune acting fibroblasts that included a CXCL1+ subset proximal to neutrophils and a CXCL12+ subset distal to the neutrophilic infiltrate. This study defines the cellular landscape of neutrophilic dermatoses and suggests dermal immune acting fibroblasts play a role in the pathogenesis of Sweets syndrome through recognition of type I interferons.

immunology↗

bioRxiv2024

Loopsim: Enrichment Analysis of ChromosomeConformation Capture with Fast EmpiricalDistribution Simulation

SummaryGene regulation is intricately influenced by the three-dimensional organization of the genome. In particular, chromatin can exist in loop structures that enable long-range regulatory interactions. By utilizing chromosome conformation capture techniques such as Hi-C, valuable information regarding the organization of these loop structures in 3D space can be obtained. While functional/feature enrichment has become a standard downstream analysis for different genomic data to provide biological context, tools that developed specifically for high throughput assays capturing chromosome conformation are relatively limited. Here, we present Loopsim, a command-line application that performs enrichment analysis on Hi-C loop profiles against user-defined regions. Loopsim efficiently simulates a background distribution using a distinctive sampling approach that considers loop size, intervals, loop-loop distances, and structure; it then computes loop-level statistics based on the empirical null distribution. AvailabilityLoopsim is a Python package available via PyPI (https://pypi.org/project/loopsim) and the source code is available on GitHub (https://github.com/CutaneousBioinf/Loopsim) under the MIT license.

bioinformatics↗

bioRxiv2024

ERK hyperactivation in epidermal keratinocytes impairs intercellular adhesion and drives Grover disease pathology

Grover disease is an acquired dermatologic disorder characterized by pruritic vesicular and eroded skin lesions. While its pathologic features are well-defined, including impaired cohesion of epidermal keratinocytes, the etiology of Grover disease remains unclear and it lacks any FDA-approved therapy. Interestingly, drug-induced Grover disease occurs in patients treated with B-RAF inhibitors that can paradoxically activate C-RAF and the downstream kinase MEK. We recently identified hyperactivation of MEK and ERK as key drivers of Darier disease, which is histologically identical to Grover disease, supporting our hypothesis that they share a pathogenic mechanism. To model drug-induced Grover disease, we treated human keratinocytes with clinically utilized B-RAF inhibitors dabrafenib or vemurafenib and leveraged a fluorescent biosensor to confirm they activated ERK, which disrupted intercellular junctions and compromised keratinocyte sheet integrity. Consistent with clinical data showing concomitant MEK blockade prevents Grover disease in patients receiving B-RAF inhibitors, we found that MEK inhibition suppressed excess ERK activity to rescue cohesion of B-RAF-inhibited keratinocytes. Validating these results, we demonstrated ERK hyperactivation in skin biopsies of vemurafenib-induced Grover disease, but also in spontaneous Grover disease. In sum, our data define a pathogenic role for ERK hyperactivation in Grover disease and support MEK inhibition as a therapeutic strategy. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=195 SRC="FIGDIR/small/591953v1_figu1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@628b3forg.highwire.dtl.DTLVardef@1a3e4aeorg.highwire.dtl.DTLVardef@fa8875org.highwire.dtl.DTLVardef@14dec1_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2024

Epidermal ZBP1 stabilizes mitochondrial Z-DNA to drive UV-induced IFN signaling in autoimmune photosensitivity

Photosensitivity is observed in numerous autoimmune diseases and drives poor quality of life and disease flares. Elevated epidermal type I interferon (IFN) production primes for photosensitivity and enhanced inflammation, but the substrates that sustain and amplify this cycle remain undefined. Here, we show that IFN-induced Z-DNA binding protein 1 (ZBP1) stabilizes ultraviolet (UV)B-induced cytosolic Z-DNA derived from oxidized mitochondrial DNA. ZBP1 is significantly upregulated in the epidermis of adult and pediatric patients with autoimmune photosensitivity. Strikingly, lupus keratinocytes accumulate extensive cytosolic Z-DNA after UVB, and transfection of keratinocytes with Z-DNA results in stronger IFN production through cGAS-STING activation compared to B-DNA. ZBP1 knockdown abrogates UV-induced IFN responses, whereas overexpression results in a lupus-like phenotype with spontaneous Z-DNA accumulation and IFN production. Our results highlight Z-DNA and ZBP1 as critical mediators for UVB-induced inflammation and uncover how type I IFNs prime for cutaneous inflammation in photosensitivity. One Sentence Summary: ZBP1 and mitochondrial Z-DNA drive autoimmune photosensitivity via cGAS-STING activation.

immunology↗

bioRxiv2024

Morphological Reprogramming of Primary Cilia Length Mitigates the Fibrotic Phenotype in fibroblasts across diverse fibrotic conditions

Fibrosis is a hallmark of systemic sclerosis (SSc) and many diverse and incurable diseases. Myofibroblast activation, a common cellular phenomenon shared across fibrotic diseases, is marked by actin polymerization known to affect primary cilia (PC) length. We discovered that fibroblasts from diverse fibrotic conditions display significantly reduced PC length ex vivo. Treatment of healthy fibroblasts with profibrotic TGF-{beta}1 induced PC shortening, while silencing ACTA2 in SSc skin fibroblasts caused PC elongation. Importantly, we found that PC length is negatively correlated with cellular expression of -SMA in TGF-{beta}1-stimulated healthy fibroblasts, or pharmacologically de-differentiated myofibroblasts. PC elongation by microtubule polymerization induction in SSc skin fibroblasts using LiCl or the HDAC6 inhibitor tubacin, reversed and mitigated fibrotic responses. Our results implicate a key role for microtubule polymerization in restraining fibrotic responses and suggest that modulation of PC dynamics may represent a potential therapeutic strategy for SSc and other treatment-resistant diseases associated with fibrosis. Teaser. PC length shortening is a hallmark of fibrosis.

cell biology↗