Biology subjects

Bieber, K.

Publications and source records attributed to Bieber, K..

7 recordsLinked to original sources

bioRxiv2026

Targeting neutrophil signaling networks in immune complex-mediated autoimmune disease

Fragment crystallizable gamma receptor (Fc{gamma}R)-induced signaling is a crucial process that determines the cellular response to immune complexes (IC) in autoimmune diseases. In several diseases including pemphigoid diseases (PD), such as epidermolysis bullosa acquisita (EBA), or rheumatoid arthritis (RA), neutrophils are prominently involved as effector cells, while others such as immune thrombocytopenia (ITP) are independent of neutrophils. At the same time, most diseases are commonly treated by broad-range immunosuppression accompanied by severe risk for adverse effects. Signal transduction inhibitors (STIs) have been successfully applied in cancer therapy. However, their use in autoimmune diseases is an emerging, but so far understudied potential treatment avenue. Therefore, we screened a target-selective compound library consisting of 155 STIs in a neutrophil-based assay and conducted a multiplex kinase activity profiling with IC-stimulated neutrophils. Thus, we found novel potential therapeutic targets that were validated both in vitro in functional neutrophil assays and in vivo in murine models of EBA Here, we demonstrate that both systemic and topical treatment with several individual STIs is effective in a prophylactic approach in these models. Furthermore, therapeutic treatment with the BTK inhibitor ibrutinib in the immunization-induced EBA model reduced disease severity by approximately 85 % and showed efficacy in additional experimental models of EBA, arthritis, and ITP. Together, the present study contributes to the elucidation of Fc{gamma}R-dependent signaling in neutrophils and identifies multiple novel promising treatment options including inhibition of PLC, PDK-1, PKC, p38, DNA-PK, KSP, c-Met, TBK-1 and BTK for IC-mediated autoimmune diseases.

immunology↗

bioRxiv2026

Mechanical Skin Stress-Induced Lesion Development via ATP-Amplified Neutrophil Extracellular Trap Formation

Neutrophilic skin diseases, including Behcet disease, Sweet syndrome, pyoderma gangrenosum (PG), and epidermolysis bullosa acquisita (EBA), are characterized by an exaggerated inflammatory response following mechanical skin stimulation, yet the underlying mechanisms remain unclear. We identify adenosine triphosphate (ATP) released from keratinocytes as a key mediator of this phenomenon, promoting neutrophil extracellular trap (NET) formation. Using an EBA murine model as a model of neutrophilic skin disease, where scratching (a prototypic mechanical stimulation) exacerbates lesional severity, we observed abundant NET deposition in lesional skin. Degradation of these NETs with DNase1 reduced clinical and histopathological severities. In vitro, purified NET components increased IL-8 secretion from keratinocytes and fibroblasts, suggesting that NETs amplify inflammation via a self-amplifying loop of neutrophil recruitment. In the EBA mouse, scratch restriction with neck collars not only attenuated clinical and histological disease severities but also decreased lesional NETosis and neutrophils. Mechanistically, keratinocytes released ATP in response to mechanical stress in vitro, and pharmacologic purinergic blockade in the EBA mice with suramin phenocopied the protective effects of scratch restriction. While ATP alone did not induce NETosis, ATP enhanced complement component 5a (C5a)-induced NET formation in vitro. These findings indicate that keratinocyte-derived ATP, released in response to mechanical stress, contributes to NETosis in a C5a-dependent manner, thereby exaggerating neutrophilic inflammation, leading to blistering and further NETosis. Histopathological analyses of EBA and PG cases also demonstrated NETs accumulation localized to the upper dermis, suggesting a conserved ATP-NET axis. Targeting this pathway may represent a promising therapeutic strategy for neutrophilic skin diseases.

immunology↗

bioRxiv2026

A human immune system mouse model for preclinical evaluation of therapies in pemphigoid disease

Pemphigoid diseases (PD) including Epidermolysis bullosa acquisita (EBA) are rare immunoglobulin G (IgG)-driven autoimmune skin blistering diseases with limited therapeutic options. Mechanistically, chronic inflammation in the skin leads to disruption of the dermal-epidermal junction (DEJ) with a crucial contribution of Fc{gamma}R-mediated activation of myeloid immune cells such as neutrophils. Thus, targeting of kinases involved in Fc{gamma}R-dependent activation of myeloid immune cells holds great promise as a therapeutic strategy. In this study, we employ human immune system (HIS) mice featuring all major human leukocytes which allows to investigate the impact of therapeutics on human immune cells in vivo. In a passive transfer approach, repetitive application of collagen VII (COL7c) specific IgG was associated with skin inflammation including infiltration of activated human immune cells and thickening of the epidermis. While application of recombinant human G-CSF boosted myeloid cell maturation and thus disease severity, treatment with Fc{gamma}R-blocking antibodies impaired disease development confirming the crucial role of human cells. Finally, small molecule PDK1 inhibitor BX-795 abrogated development of skin inflammation associated with reduced leukocyte infiltration and activation supporting the role of PDK1 in Fc{gamma}R-driven immune cell activation. This study establishes the first in vivo model of EBA in HIS mice and reveals its suitability for pre-clinical screening and evaluation of therapeutic agents. Importantly, it highlights the potential of kinase inhibition for treatment of EBA.

immunology↗

bioRxiv2025

CDK7, CDK9, or CDK11 Inhibition Reduces Neutrophil-Driven Inflammation and Tissue Damage in Experimental Autoimmune Models

BackgroundCyclin-dependent kinases (CDKs) are involved in basic cellular processes like regulation of cell-cycle progression and transcription. However, recent data also indicate a specific role in terminally differentiated neutrophils by promoting reactive oxygen species (ROS) release, degranulation, neutrophil extracellular trap formation, or apoptosis. Since these mechanisms are implicated in multiple autoimmune diseases, we aimed to delineate the role of CDKs in IC-mediated autoimmune diseases both in vitro and in vivo. MethodsWe analyzed CDK gene expression in unstimulated and immune complex (IC)-stimulated neutrophils. Subsequently, we investigated the effect of pharmacological CDK inhibition on IC-activated neutrophil functions. To analyze the inhibitors in a more translational approach, we proceeded with the systemic and topical application of the effective inhibitors in a murine antibody transfer-induced local epidermolysis bullosa acquisita (EBA) model. The most efficient inhibitor, MC180295, was validated in two other IC-mediated models of autoimmune disease: Serum-transfer arthritis (STA), which also, but not exclusively, depends on neutrophils and immune thrombocytopenia (ITP), which is considered less neutrophil-dependent. ResultsWe found 14 CDKs expressed in unstimulated cells, while the IC-stimulation showed an upregulation of CDK2 and CDK4 expression. Inhibitors selectively targeting CDK1, CDK2, CDK4/6, CDK7, CDK9, CDK11, and CDK12 showed effects on different neutrophil functions (surface activation marker expression, ROS release, adhesion, apoptosis) in vitro. In the predominantly neutrophil-driven EBA model, we observed a reduction of disease severity upon treatment with CDK7, CDK9, or CDK11 inhibitors. Inhibiting these CDKs with topical THZ2, MC180295, or OTS964, respectively, also improved the clinical phenotype. In line with our hypothesis, MC180295 impaired the development of STA, but not ITP. ConclusionsCDK7, CDK11, and especially CDK9 inhibition show therapeutic potential in IC-driven neutrophil-mediated diseases such as rheumatoid arthritis and EBA.

immunology↗

bioRxiv2025

ERK5 is required for neutrophil-mediated ROS release and essential in epidermolysis bullosa acquisita

Neutrophils are key effector cells in antibody-mediated autoimmune diseases, contributing to inflammation via the release of reactive oxygen species (ROS). Extracellular signal-regulated kinase 5 (ERK5), a member of the MAPK family, is expressed in neutrophils but its role in autoimmune disease pathogenesis remains unclear. We investigated the functional relevance of ERK5 in antibody-mediated autoimmune diseases by comparing neutrophil-dependent (epidermolysis bullosa acquisita, EBA; serum transfer arthritis, STA) and neutrophil-independent (immune thrombocytopenia, ITP) murine models using the small-molecule ERK5 inhibitor XMD8-92. In vitro, pharmacological ERK5 inhibition specifically reduced neutrophil ROS release and CD62L shedding without affecting adhesion, chemotaxis, or CD18 expression. No major effects on viability were observed. In vivo, ERK5 inhibition with XMD8-92 significantly ameliorated antibody transfer-induced EBA, supporting a critical role of neutrophil-derived ROS in disease pathogenesis. In STA and ITP, ERK5 inhibition did not affect clinical outcomes. Together, these findings highlight ERK5 as a regulator of neutrophil ROS release and a potential therapeutic target in ROS-driven autoimmune diseases such as EBA.

immunology↗

bioRxiv2025

Gut Microbiota Modulates and Predicts Disease Severity in Experimental Pemphigoid Disease

Pemphigoid diseases (PD) are autoimmune blistering diseases with reported alterations in skin and gut microbiota, though their causal contribution to disease pathophysiology remains unclear. Using a passive model of bullous pemphigoid-like epidermolysis bullosa acquisita (BP-like EBA), we compared C57BL/6J mice from two sources (in-house vs. Charles River) that differed in their baseline microbiota. Charles River mice developed significantly less severe disease. Co-housing led to partial homogenization of the gut microbiota, driven by asymmetric transfer of taxa from Charles River to in-house mice, which corresponded with reduced disease severity in the latter. The skin microbiota, however, showed limited exchange. Disease severity was inversely associated with gut microbial alpha diversity, with protective taxa such as Lactobacillus intestinalis and Parabacteroides distasonis enriched in Charles River mice, while pro-inflammatory taxa including Turicimonas muris and Muribaculum intestinale were enriched in in-house mice. A machine learning model further identified a gut taxon most closely matching the candidate genus Scatocola as a strong negative predictor of disease severity. Through experimental exposure and uptake of variable gut microbiota, these findings suggest a direct role of gut microbiota in mediating the severity of the experimental BP-like EBA and highlight the potential of microbiota-based strategies for therapeutic intervention in PD.

microbiology↗

bioRxiv2025

CD19xCD3 bispecific T cell engager treatment induces remission in experimental pemphigoid disease

Pemphigoid diseases (PDs) are autoimmune disorders marked by autoantibodies (Aab) against skin and mucous membrane proteins, causing muco-cutaneous blistering in predominantly elderly patients. Since current therapeutics are often insufficient, PDs impose a significant morbidity and mortality burden. CD19xCD3 bispecific T cell engagers (TCEs) - originally developed for B cell malignancies - have shown promise in treatment-refractory autoimmune diseases like systemic sclerosis and rheumatoid arthritis. To explore their potential in PDs, we tested a murine CD19xCD3 TCE in a mouse model of epidermolysis bullosa acquisita (EBA), a prototypical PD. The TCE selectively depleted B cells in blood and bone marrow, but not spleen, of healthy mice. Mice with clinically manifest immunization-induced EBA were randomized to receive either the CD19xCD3 TCE or control treatment upon reaching a predefined disease severity. After 13 weeks, 45% of TCE-treated mice achieved remission, versus 23% of controls. This improvement correlated with reduced antigen-specific B cells, though total and antigen-specific IgG levels were unchanged. These findings suggest that CD19xCD3 TCE preferentially target autoreactive B cells and may be effective at lower doses than those used in oncology. Our data support the potential of CD19xCD3 bispecific T cell engagers as a therapeutic strategy for PDs. eTOC SynopsisGross, Jochimsen, Drager and colleagues demonstrate that CD19xCD3 bispecific T cell engagers, can selectively target autoreactive B cells and induce remission in a mouse model of pemphigoid disease, highlighting their potential as a novel therapeutic strategy for autoimmune blistering disorders.

immunology↗