Biology subjects

Amber, K. T.

Publications and source records attributed to Amber, K. T..

3 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↗

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↗

bioRxiv2024

IgG autoantibodies in bullous pemphigoid directly induce a pathogenic MyD88-dependent pro-inflammatory response in keratinocytes:

AbstractWhile autoantibodies in bullous pemphigoid (BP) are known to activate the innate immune response, their direct effect on keratinocytes, and the contribution of BP-IgG autoantibody-dependent keratinocyte responses to BP pathology is largely unknown. Herein, we performed multiplex immunoassays and bulk RNA-seq on primary keratinocytes treated with IgG from BP patients or controls. We identified a pro-inflammatory and proteolytic response with release of several cytokines (IL-6, IL-24, TGF-{beta}1), chemokines (CXCL16, CTACK, MIP-3{beta}, RANTES), C1s, DPP4, and MMP-9. We further validated this response using spatial transcriptomics and scRNA-seq of diseased and control skin. Blistering itself appeared to be major driver of this inflammatory response, with attached BP skin and spongiotic dermatitis revealing highly similar transcriptomes. Based on elevated levels of MyD88 and MyD88-dependent cytokines, we studied the impact of MyD88 deficiency in keratinocytes and demonstrated that MyD88 regulates BP-IgG-induced expression of IL-8, IL-24, and MMP-9. Induction of experimental BP in mice with Krt14-specific Myd88 knockout revealed significantly decreased disease severity with decreased serum levels of IL-1{beta}, IL-4, and IL-9 indicating the contributory role of keratinocyte-derived skin inflammation towards systemic response. Our work demonstrates the key contributions of keratinocyte and MyD88 dependent signaling in response to autoantibodies in BP. Key Messages-IgG antibodies from bullous pemphigoid (BP) patients induce significant upregulation of several inflammatory markers in keratinocytes including cytokines (IL-6, IL-24, TGF-{beta}1), chemokines (CXCL16, CTACK, MIP-3{beta}, RANTES), C1s, DPP4, and MMP9. Several of these markers, including IL-8, IL-24, and MMP9 are regulated by MyD88. -Spatial transcriptomics reveals that BP patient blistered skin demonstrated similar transcriptomic profiles to BP-IgG-treated keratinocytes. With attached skin demonstrating a comparable transcriptome to that seen in spongiotic dermatitis. -In a mouse BP model, keratinocyte-specific MyD88 deficiency results in decreased disease severity with a subsequent decrease in serum IL-1{beta}, IL-4, and IL-9 levels. Capsule summaryIgG from patients with bullous pemphigoid (BP) induces a pro-inflammatory response in keratinocytes, indicating their direct role in driving the inflammatory response in BP.

immunology↗