TY - JOUR A1 - Gernert, Michael A1 - Kiesel, Matthias A1 - Fröhlich, Matthias A1 - Renner, Regina A1 - Strunz, Patrick-Pascal A1 - Portegys, Jan A1 - Tony, Hans-Peter A1 - Schmalzing, Marc A1 - Schwaneck, Eva Christina T1 - High Prevalence of Genital Human Papillomavirus Infection in Patients With Primary Immunodeficiencies JF - Frontiers in Immunology N2 - Background Genital human papillomavirus (HPV)-infections are common in the general population and are responsible for relevant numbers of epithelial malignancies. Much data on the HPV-prevalence is available for secondary immunodeficiencies, especially for patients with human immunodeficiency virus (HIV)-infection. Little is known about the genital HPV-prevalence in patients with primary immunodeficiencies (PIDs). Methods We performed a cross-sectional study of patients with PIDs and took genital swabs from male and female patients, which were analyzed with polymerase chain reaction for the presence of HPV-DNA. Clinical and laboratory data was collected to identify risk factors. Results 28 PID patients were included in this study. 10 of 28 (35.7%) had HPV-DNA in their genital swabs. 6 patients had high-risk HPV-types (21.4%). Most patients had asymptomatic HPV-infections, as genital warts were rare (2 of 28 patients) and HPV-associated malignancy was absent. Differences in the HPV-positivity regarding clinical PID-diagnosis, duration of PID, age, sex, immunosuppression, immunoglobulin replacement, or circumcision in males were not present. HPV-positive PID patients had higher numbers of T cells (CD3\(^+\)), of cytotoxic T cells (CD3\(^+\)/CD8\(^+\)), of transitional B cells (CD19\(^+\)/CD38\(^{++}\)/CD10\(^+\)/IgD\(^+\)), and of plasmablasts (CD19\(^+\)/CD38\(^+\)/CD27\(^{++}\)/IgD\(^-\)) compared to HPV-negative. Conclusion PID patients exhibit a high rate of genital HPV-infections with a high rate of high-risk HPV-types. Regular screening for symptomatic genital HPV-infection and HPV-associated malignancy in PID patients seems recommendable. KW - human papillomavirus KW - primary immunodeficiency KW - inborn errors of immunity (IEIs) KW - common variable immunodeficiency (CVID) KW - genital warts Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-250273 SN - 1664-3224 VL - 12 ER - TY - THES A1 - Fröhlich, Matthias T1 - Die funktionelle Bedeutung der Heteromerisierung von Serotonin-1A und Serotonin-7 Rezeptoren T1 - Functional importance of heteromerisation of serotonin-1A and serotonin-7 receptors N2 - Die Heterodimerisierung von G- Protein gekoppelten Rezeptoren (GPCR) stellt ein aktuelles Forschungsgebiet dar, das molekulare Erklärungsmöglichkeiten für die Vielfalt der Signalwege über solche Rezeptoren aufzeigt. Die genauen Funktionen diese Konstrukte in vivo sind bisher erst in Ansätzen erforscht, ebenso wenig die molekularbiologischen Mechanismen. Für die beiden Serotoninrezeptoren 5-HT1A und 5-HT7 konnte Heterodimerisierung molekular nachgewiesen werden, in ihren physiologischen Mechanismen und Effekten sollte daher eine Charakterisierung vorgenommen werden. Mittels elektrophysiologischer Messverfahren wurden Ströme an dem heterologen Expressionsmodell der Oozyten des Krallenfrosches Xenopus laevis mittels Voltage-Clamp Technik an Kaliumionenkanälen (Kir3 und TASK-1) gemessen. Hierbei konnte gezeigt werden, dass die heterodimere Koexpression beider Rezeptoren eine signifikante Reduktion des Rezeptor-aktivierten Kanalstroms im Vergleich zur homomeren Expression zur Folge hatte. Weitere Experimente konnten dann zeigen, dass diese Effekte spezifisch für dieses Rezeptorheterodimer sind, und dass die Effekte von der Dosis bzw. dem Verhältnis der exprimierten cRNA abhängen. In Fluoreszenzmessung konnte zudem gezeigt werden, dass die Reduktion der Stromamplitude in der heterodimeren Expression nicht auf eine Reduktion von Kanalproteinen in der Zellmembran zurückzuführen ist. Zur weiteren Charakterisierung des bisher erst in Ansätzen erforschten 5-HT7 Rezeptors wurde dieser abschließend mit einem ß- adrenergen Rezeptor verglichen, der über den gleichen Signalweg bzw. Ionenkanal funktioniert. Auch hier zeigte sich eine signifikante Reduktion des Kanalstroms beim 5-HT7 Rezeptor. Die physiologische Relevanz dieser Ergebnisse liegt darin begründet, dass ein weiterführendes Verständnis von 5-HT Rezeptor vermittelten Signalwegen, insbesondere von der Bedeutung und den Mechanismen ihrer Heterodimersierung, neue pathophysiologische Zusammenhänge verdeutlicht. Speziell im Hinblick auf Erkrankungen, die mit den 5-HT Rezeptoren assoziiert sind, wie etwa Depressionen und Angststörungen, soll sich hieraus die Möglichkeit spezifischerer Therapien ergeben. N2 - Heteromerisation of G-protein coupled receptors (GPCR)is a current object of research to find out diversity of signaling pathways. The functional details of those constructs in vivo are not yet understood, also molecular mechanisms. For the Serotonin receptors 1A and 7 heteromerisation recently could be shown, therefore intention now is to make a physiological characterization. By electrophysiological methods, i.e. voltage clamp, currents of potassium channels (Kir3 and TASK-1) could be detected using the heterologous expression system of oocytes of xenopus leavis. So we could demonstrate, that heterologous expression of both receptors leads to a reduced current amplitude in comparison to homologous expression of one receptor. Those effects where shown to be specific and dependend of cRNA dose. By using fluorescense tagged Kir-channel we could demonstrate that the effect doesn't base on less channel protein in cell surface of the oocytes. Another point of interest was the characterization of Serotonin-7 channel. Therefore we analyzed a dose-response-relationship, afterwards we compared data with a ß-adrenergic receptore in heteromeric expression with Serotonin-1A. The physiological relevance of those experiments is to understand serotonin pathways an metabolism that is very important in development of mental disorders of fear or major depression. KW - Heteromerisierung KW - Serotonin KW - Serotonin-1A KW - Serotonin-7 KW - GIRK KW - TASK-1 KW - heteromerisation KW - serotonin KW - serotonin-1A KW - serotonin-7 KW - GIRK KW - TASK-1 Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-55508 ER - TY - JOUR A1 - Guggenberger, Konstanze Viktoria A1 - Torre, Giulia Dalla A1 - Ludwig, Ute A1 - Vogel, Patrick A1 - Weng, Andreas Max A1 - Vogt, Marius Lothar A1 - Fröhlich, Matthias A1 - Schmalzing, Marc A1 - Raithel, Esther A1 - Forman, Christoph A1 - Urbach, Horst A1 - Meckel, Stephan A1 - Bley, Thorsten Alexander T1 - Vasa vasorum of proximal cerebral arteries after dural crossing - potential imaging confounder in diagnosing intracranial vasculitis in elderly subjects on black-blood MRI JF - European Radiology N2 - Objectives Vessel wall enhancement (VWE) may be commonly seen on MRI images of asymptomatic subjects. This study aimed to characterize the VWE of the proximal internal carotid (ICA) and vertebral arteries (VA) in a non-vasculitic elderly patient cohort. Methods Cranial MRI scans at 3 Tesla were performed in 43 patients (aged ≥ 50 years) with known malignancy for exclusion of cerebral metastases. For vessel wall imaging (VWI), a high-resolution compressed-sensing black-blood 3D T1-weighted fast (turbo) spin echo sequence (T1 CS-SPACE prototype) was applied post gadolinium with an isotropic resolution of 0.55 mm. Bilateral proximal intradural ICA and VA segments were evaluated for presence, morphology, and longitudinal extension of VWE. Results Concentric VWE of the proximal intradural ICA was found in 13 (30%) patients, and of the proximal intradural VA in 39 (91%) patients. Mean longitudinal extension of VWE after dural entry was 13 mm in the VA and 2 mm in the ICA. In 14 of 39 patients (36%) with proximal intradural VWE, morphology of VWE was suggestive of the mere presence of vasa vasorum. In 25 patients (64 %), morphology indicated atherosclerotic lesions in addition to vasa vasorum. Conclusions Vasa vasorum may account for concentric VWE within the proximal 2 mm of the ICA and 13 mm of the VA after dural entry in elderly subjects. Concentric VWE in these locations should not be confused with large artery vasculitis. Distal to these segments, VWE may be more likely related to pathologic conditions such as vasculitis. KW - vertebral artery KW - magnetic resonance imaging KW - vasa vasorum KW - large artery vasculitis KW - Atherosclerosis, intracranial arteries Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-266524 SN - 1432-1084 VL - 32 IS - 2 ER - TY - JOUR A1 - Fröhlich, Matthias A1 - Serfling, Sebastian A1 - Higuchi, Takahiro A1 - Pomper, Martin G. A1 - Rowe, Steven P. A1 - Schmalzing, Marc A1 - Tony, Hans-Peter A1 - Gernert, Michael A1 - Strunz, Patrick-Pascal A1 - Portegys, Jan A1 - Schwaneck, Eva-Christina A1 - Gadeholt, Ottar A1 - Weich, Alexander A1 - Buck, Andreas K. A1 - Bley, Thorsten A. A1 - Guggenberger, Konstanze V. A1 - Werner, Rudolf A. T1 - Whole-Body [\(^{18}\)F]FDG PET/CT Can Alter Diagnosis in Patients with Suspected Rheumatic Disease JF - Diagnostics N2 - The 2-deoxy-d-[\(^{18}\)F]fluoro-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) is widely utilized to assess the vascular and articular inflammatory burden of patients with a suspected diagnosis of rheumatic disease. We aimed to elucidate the impact of [\(^{18}\)F]FDG PET/CT on change in initially suspected diagnosis in patients at the time of the scan. Thirty-four patients, who had undergone [\(^{18}\)F]FDG PET/CT, were enrolled and the initially suspected diagnosis prior to [18F]FDG PET/CT was compared to the final diagnosis. In addition, a semi-quantitative analysis including vessel wall-to-liver (VLR) and joint-to-liver (JLR) ratios was also conducted. Prior to [\(^{18}\)F]FDG PET/CT, 22/34 (64.7%) of patients did not have an established diagnosis, whereas in 7/34 (20.6%), polymyalgia rheumatica (PMR) was suspected, and in 5/34 (14.7%), giant cell arteritis (GCA) was suspected by the referring rheumatologists. After [\(^{18}\)F]FDG PET/CT, the diagnosis was GCA in 19/34 (55.9%), combined GCA and PMR (GCA + PMR) in 9/34 (26.5%) and PMR in the remaining 6/34 (17.6%). As such, [\(^{18}\)F]FDG PET/CT altered suspected diagnosis in 28/34 (82.4%), including in all unclear cases. VLR of patients whose final diagnosis was GCA tended to be significantly higher when compared to VLR in PMR (GCA, 1.01 ± 0.08 (95%CI, 0.95–1.1) vs. PMR, 0.92 ± 0.1 (95%CI, 0.85–0.99), p = 0.07), but not when compared to PMR + GCA (1.04 ± 0.14 (95%CI, 0.95–1.13), p = 1). JLR of individuals finally diagnosed with PMR (0.94 ± 0.16, (95%CI, 0.83–1.06)), however, was significantly increased relative to JLR in GCA (0.58 ± 0.04 (95%CI, 0.55–0.61)) and GCA + PMR (0.64 ± 0.09 (95%CI, 0.57–0.71); p < 0.0001, respectively). In individuals with a suspected diagnosis of rheumatic disease, an inflammatory-directed [\(^{18}\)F]FDG PET/CT can alter diagnosis in the majority of the cases, particularly in subjects who were referred because of diagnostic uncertainty. Semi-quantitative assessment may be helpful in establishing a final diagnosis of PMR, supporting the notion that a quantitative whole-body read-out may be useful in unclear cases. KW - giant cell arteritis KW - GCA KW - [18F]FDG PET/CT KW - vasculature KW - inflammation KW - polymyalgia rheumatica KW - PMR KW - vasculitis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-250227 SN - 2075-4418 VL - 11 IS - 11 ER - TY - JOUR A1 - Gernert, Michael A1 - Schmalzing, Marc A1 - Tony, Hans-Peter A1 - Strunz, Patrick-Pascal A1 - Schwaneck, Eva Christina A1 - Fröhlich, Matthias T1 - Calprotectin (S100A8/S100A9) detects inflammatory activity in rheumatoid arthritis patients receiving tocilizumab therapy JF - Arthritis Research & Therapy N2 - Background Assessing serological inflammation is difficult in tocilizumab (TCZ)-treated rheumatoid arthritis (RA) patients, as standard inflammation parameters, like erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), are influenced by interleukin-6-receptor inhibition. Calprotectin in the serum, also named S100A8/S100A9, might be a more useful inflammation parameter in TCZ-treated patients. Methods Sixty-nine RA patients taking TCZ were included. Serum-calprotectin levels were assessed, as well as ESR, CRP, need for a change in disease-modifying anti-rheumatic drugs due to RA activity (= active RA), and the RA clinical disease activity score (CDAI). Forty-five RA patients taking tumor-necrosis factor-inhibitors (TNFi) were investigated for the same parameters. Results TCZ-treated patients with active RA had higher calprotectin values than not active RA patients (4155.5 [inter quartile range 1865.3–6068.3] vs 1040.0 [676.0–1638.0] ng/ml, P < 0.001). A calprotectin cut-off value of 1916.5 ng/ml resulted in a sensitivity and specificity of 80.0 %, respectively, for the detection of RA disease activity. Calprotectin values correlated with CDAI-scores (r = 0.228; P = 0.011). ESR and CRP were less suitable to detect RA activity in TCZ-treated patients. Also TNFi-treated patients with active RA had higher calprotectin values compared to not active RA (5422.0 [3749.0–8150.8] vs 1845.0 [832.0–2569.0] ng/ml, P < 0.001). The calprotectin value with the best sensitivity and specificity for detecting RA activity was 3690.5 ng/ml among TNFi-treated patients. Conclusion Calprotectin in the serum can be a useful inflammation parameter despite TCZ-treatment. KW - calprotectin KW - inflammation marker KW - c-reactive protein KW - tocilizumab KW - rheumatoid arthritis KW - S100A8/S100A9 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300523 VL - 24 IS - 1 ER - TY - JOUR A1 - Kemmler, Wolfgang A1 - Kohl, Matthias A1 - Fröhlich, Michael A1 - Jakob, Franz A1 - Engelke, Klaus A1 - von Stengel, Simon A1 - Schoene, Daniel T1 - Effects of High‐Intensity Resistance Training on Osteopenia and Sarcopenia Parameters in Older Men with Osteosarcopenia—One‐Year Results of the Randomized Controlled Franconian Osteopenia and Sarcopenia Trial (FrOST) JF - Journal of Bone and Mineral Research N2 - Dynamic resistance exercise (DRT) might be the most promising agent for fighting sarcopenia in older people. However, the positive effect of DRT on osteopenia/osteoporosis in men has still to be confirmed. To evaluate the effect of low‐volume/high‐intensity (HIT)‐DRT on bone mineral density (BMD) and skeletal muscle mass index (SMI) in men with osteosarcopenia, we initiated the Franconian Osteopenia and Sarcopenia Trial (FrOST). Forty‐three sedentary community‐dwelling older men (aged 73 to 91 years) with osteopenia/osteoporosis and SMI‐based sarcopenia were randomly assigned to a HIT‐RT exercise group (EG; n = 21) or a control group (CG; n = 22). HIT‐RT provided a progressive, periodized single‐set DRT on machines with high intensity, effort, and velocity twice a week, while CG maintained their lifestyle. Both groups were adequately supplemented with whey protein, vitamin D, and calcium. Primary study endpoint was integral lumbar spine (LS) BMD as determined by quantitative computed tomography. Core secondary study endpoint was SMI as determined by dual‐energy X‐ray absorptiometry. Additional study endpoints were BMD at the total hip and maximum isokinetic hip−/leg‐extensor strength (leg press). After 12 months of exercise, LS‐BMD was maintained in the EG and decreased significantly in the CG, resulting in significant between‐group differences (p < 0.001; standardized mean difference [SMD] = 0.90). In parallel, SMI increased significantly in the EG and decreased significantly in the CG (p < 0.001; SMD = 1.95). Total hip BMD changes did not differ significantly between the groups (p = 0.064; SMD = 0.65), whereas changes in maximum hip−/leg‐extensor strength were much more prominent (p < 0.001; SMD = 1.92) in the EG. Considering dropout (n = 2), attendance rate (95%), and unintended side effects/injuries (n = 0), we believe our HIT‐RT protocol to be feasible, attractive, and safe. In summary, we conclude that our combined low‐threshold HIT‐RT/protein/vitamin D/calcium intervention was feasible, safe, and effective for tackling sarcopenia and osteopenia/osteoporosis in older men with osteosarcopenia. KW - exercise KW - osteoporosis KW - sarcopenia KW - aging KW - bone QCT Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-214609 VL - 35 IS - 9 SP - 1634 EP - 1644 ER - TY - JOUR A1 - Gernert, Michael A1 - Tony, Hans-Peter A1 - Schwanek, Eva Christina A1 - Gadeholt, Ottar A1 - Fröhlich, Matthias A1 - Portegys, Jan A1 - Strunz, Patrick-Pascal A1 - Schmalzing, Marc T1 - Lymphocyte subsets in the peripheral blood are disturbed in systemic sclerosis patients and can be changed by immunosuppressive medication JF - Rheumatology International N2 - Systemic sclerosis (SSc) is a severe chronic disease with a broad spectrum of clinical manifestations. SSc displays disturbed lymphocyte homeostasis. Immunosuppressive medications targeting T or B cells can improve disease manifestations. SSc clinical manifestations and immunosuppressive medication in itself can cause changes in lymphocyte subsets. The aim of this study was to investigate peripheral lymphocyte homeostasis in SSc with regards to the immunosuppression and to major organ involvement. 44 SSc patients and 19 healthy donors (HD) were included. Immunophenotyping of peripheral whole blood by fluorescence-activated cell sorting was performed. Cytokine secretions of stimulated B cell cultures were measured. SSc patients without immunosuppression compared to HD displayed lower γδ T cells, lower T helper cells (CD3+/CD4+), lower transitional B cells (CD19+/CD38++/CD10+/IgD+), lower pre-switched memory B cells (CD19+/CD27+/IgD+), and lower post-switched memory B cells (CD19+/CD27+/IgD-). There was no difference in the cytokine production of whole B cell cultures between SSc and HD. Within the SSc cohort, mycophenolate intake was associated with lower T helper cells and lower NK cells (CD56+/CD3-). The described differences in peripheral lymphocyte subsets between SSc and HD generate further insight in SSc pathogenesis. Lymphocyte changes under effective immunosuppression indicate how lymphocyte homeostasis in SSc might be restored. KW - mycophenolate KW - systemic sclerosis KW - scleroderma KW - memory B cells KW - B cell culture KW - cytokines KW - γδ T cells KW - immunophenotyping Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-266482 SN - 1437-160X VL - 42 IS - 8 ER - TY - JOUR A1 - Gernert, Michael A1 - Tony, Hans-Peter A1 - Schwaneck, Eva Christina A1 - Fröhlich, Matthias A1 - Schmalzing, Marc T1 - Low B cell counts as risk factor for infectious complications in systemic sclerosis after autologous hematopoietic stem cell transplantation JF - Arthritis Research & Therapy N2 - Background Autologous hematopoietic stem cell transplantation (aHSCT) is a treatment option for a selected group of systemic sclerosis (SSc) patients with good available evidence but can be associated with considerable morbidity and mortality. The aim of this study was to describe infectious complications and distinct immune reconstitution patterns after aHSCT and to detect risk factors in lymphocyte subsets, which are associated with an elevated rate of infections after aHSCT. Methods Seventeen patients with SSc were included in this single-center retrospective cohort study. Clinical and laboratory data was collected before and for 12 months after aHSCT, including immunophenotyping of peripheral whole blood by fluorescence-activated cell sorting. Results Cytomegalovirus (CMV) reactivations were common in CMV-IgG-positive patients (50%) and needed treatment. Mycotic infections occurred in 17.6%. One patient died (resulting in a mortality of 5.9%) due to pneumonia with consecutive sepsis. All patients showed decreased T helper cells (CD3\(^+\)/CD4\(^+\)) and within the B cell compartment decreased post-switched memory B cells (CD19\(^+\)/CD27\(^+\)/IgD\(^-\)) and elevated naive B cells (CD19\(^+\)/CD27\(^-\)/IgD\(^+\)) until 12 months after aHSCT. Patients who developed infections had significantly lower B cells before aHSCT than patients who did not develop infections. Conclusion After aHSCT, monitoring for infectious complications, especially for CMV reactivations, is crucial as the reconstitution of the immune system takes longer than 12 months. Low peripheral B cells might be a risk factor for an elevated infection rate. KW - Systemic sclerosis KW - Autologous hematopoietic stem cell transplantation KW - Infectious complications KW - CMV reactivation KW - B cells Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229962 VL - 22 ER - TY - JOUR A1 - Gernert, Michael A1 - Tony, Hans-Peter A1 - Fröhlich, Matthias A1 - Schwaneck, Eva Christina A1 - Schmalzing, Marc T1 - Immunosuppressive therapy after autologous hematopoietic stem cell transplantation in systemic sclerosis patients — high efficacy of Rituximab JF - Frontiers in Immunology N2 - Background Systemic sclerosis (SSc) patients often need immunosuppressive medication (IS) for disease control. If SSc is progressive despite IS, autologous hematopoietic stem cell transplantation (aHSCT) is a treatment option for selected SSc patients. aHSCT is effective with good available evidence, but not all patients achieve a treatment-free remission after aHSCT. Thus far, data about the need of IS after aHSCT in SSc is not published. The aim of this study was to investigate the use of IS after aHSCT, its efficacy, and the occurrence of severe adverse events (SAEs). Methods Twenty-seven patients with SSc who had undergone aHSCT were included in this single-center retrospective cohort study. Clinical data, including IS, SAEs, and lung function data, were collected. Results Sixteen of 27 (59.3%) patients received IS after aHSCT. Methotrexate, rituximab, mycophenolate, cyclophosphamide, and hydroxychloroquine were most commonly used. The main reason for starting IS was SSc progress. Nine patients received rituximab after aHSCT and showed an improvement in modified Rodnan skin score and a stabilization of lung function 2 years after rituximab. SAEs in patients with IS after aHSCT (50.0%) were not more common than in patients without IS (54.6%). SAEs were mostly due to SSc progress, secondary autoimmune diseases, or infections. Two deaths after aHSCT were transplantation related and three during long-term follow-up due to pulmonary arterial hypertension. Conclusion Disease progression and secondary autoimmune diseases may necessitate IS after aHSCT in SSc. Rituximab seems to be an efficacious treatment option in this setting. Long-term data on the safety of aHSCT is reassuring. KW - systemic sclerosis KW - scleroderma KW - autologous hematopoietic stem cell transplantation KW - immunosuppression KW - adverse events KW - rituximab Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254345 SN - 1664-3224 VL - 12 ER - TY - JOUR A1 - Hoesl, Christine A1 - Fröhlich, Thomas A1 - Posch, Christian A1 - Kneitz, Hermann A1 - Goebeler, Matthias A1 - Schneider, Marlon R. A1 - Dahlhoff, Maik T1 - The transmembrane protein LRIG1 triggers melanocytic tumor development following chemically induced skin carcinogenesis JF - Molecular Oncology N2 - The incidence of melanoma and nonmelanoma skin cancer has increased tremendously in recent years. Although novel treatment options have significantly improved patient outcomes, the prognosis for most patients with an advanced disease remains dismal. It is, thus, imperative to understand the molecular mechanisms involved in skin carcinogenesis in order to develop new targeted treatment strategies. Receptor tyrosine kinases (RTK) like the ERBB receptor family, including EGFR/ERBB1, ERBB2/NEU, ERBB3, and ERBB4, are important regulators of skin homeostasis and their dysregulation often results in cancer, which makes them attractive therapeutic targets. Members of the leucine‐rich repeats and immunoglobulin‐like domains protein family (LRIG1‐3) are ERBB regulators and thus potential therapeutic targets to manipulate ERBB receptors. Here, we analyzed the function of LRIG1 during chemically induced skin carcinogenesis in transgenic mice expressing LRIG1 in the skin under the control of the keratin 5 promoter (LRIG1‐TG mice). We observed a significant induction of melanocytic tumor formation in LRIG1‐TG mice and no difference in papilloma incidence between LRIG1‐TG and control mice. Our findings also revealed that LRIG1 affects ERBB signaling via decreased phosphorylation of EGFR and increased activation of the oncoprotein ERBB2 during skin carcinogenesis. The epidermal proliferation rate was significantly decreased during epidermal tumorigenesis under LRIG1 overexpression, and the apoptosis marker cleaved caspase 3 was significantly activated in the epidermis of transgenic LRIG1 mice. Additionally, we detected LRIG1 expression in human cutaneous squamous cell carcinoma and melanoma samples. Therefore, we depleted LRIG1 in human melanoma cells (A375) by CRISPR/Cas9 technology and found that this caused EGFR and ERBB3 downregulation in A375 LRIG1 knockout cells 6 h following stimulation with EGF. In conclusion, our study demonstrated that LRIG1‐TG mice develop melanocytic skin tumors during chemical skin carcinogenesis and a deletion of LRIG1 in human melanoma cells reduces EGFR and ERBB3 expression after EGF stimulation. KW - ERBB receptors KW - LRIG1 KW - melanoma KW - mouse model KW - skin carcinogenesis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238925 VL - 15 IS - 8 SP - 2140 EP - 2155 ER -