A Subset of Skin Macrophages Contributes to the Surveillance and Regeneration of Local Nerves.

The skin comprises tissue macrophages as the most abundant resident immune cell type. Their diverse tasks including resistance against invading pathogens, attraction of bypassing immune cells from vessels, and tissue repair require dynamic specification. Here, we delineated the postnatal development of dermal macrophages and their differentiation into subsets by adapting single-cell transcriptomics, fate mapping, and imaging. Thereby we identified a phenotypically and transcriptionally distinct subset of prenatally seeded dermal macrophages that self-maintained with very low postnatal exchange by hematopoietic stem cells. These macrophages specifically interacted with sensory nerves and surveilled and trimmed the myelin sheath. Overall, resident dermal macrophages contributed to axon sprouting after mechanical injury. In summary, our data show long-lasting functional specification of macrophages in the dermis that is driven by stepwise adaptation to guiding structures and ensures codevelopment of ontogenetically distinct cells within the same compartment.

Framework and baseline examination of the German National Cohort (NAKO).

The German National Cohort (NAKO) is a multidisciplinary, population-based prospective cohort study that aims to investigate the causes of widespread diseases, identify risk factors and improve early detection and prevention of disease. Specifically, NAKO is designed to identify novel and better characterize established risk and protection factors for the development of cardiovascular diseases, cancer, diabetes, neurodegenerative and psychiatric diseases, musculoskeletal diseases, respiratory and infectious diseases in a random sample of the general population. Between 2014 and 2019, a total of 205,415 men and women aged 19-74 years were recruited and examined in 18 study centres in Germany. The baseline assessment included a face-to-face interview, self-administered questionnaires and a wide range of biomedical examinations. Biomaterials were collected from all participants including serum, EDTA plasma, buffy coats, RNA and erythrocytes, urine, saliva, nasal swabs and stool. In 56,971 participants, an intensified examination programme was implemented. Whole-body 3T magnetic resonance imaging was performed in 30,861 participants on dedicated scanners. NAKO collects follow-up information on incident diseases through a combination of active follow-up using self-report via written questionnaires at 2-3 year intervals and passive follow-up via record linkages. All study participants are invited for re-examinations at the study centres in 4-5 year intervals. Thereby, longitudinal information on changes in risk factor profiles and in vascular, cardiac, metabolic, neurocognitive, pulmonary and sensory function is collected. NAKO is a major resource for population-based epidemiology to identify new and tailored strategies for early detection, prediction, prevention and treatment of major diseases for the next 30 years.

[Occurrence of bronchial asthma and age at initial asthma diagnosis-first results of the German National Cohort]. / Häufigkeit von Asthma bronchiale und Alter bei der Erstdiagnose ­ erste Ergebnisse der NAKO Gesundheitsstudie.

BACKGROUND: Asthma is one of the most common chronic diseases in both children and adults. Asthma first occurring in adulthood (adult-onset asthma, AOA) is associated with poorer prognosis compared to childhood-onset asthma (COA), which urgently calls for more research in this area. The aim of this work was to analyze the data on asthma collected in the German National Cohort and compare it with the German Health Interview and Examination Survey for Adults (DEGS), in particular regarding AOA. MATERIAL AND METHODS: Our analysis was based on the dataset of the main questionnaire at mid-term of the German National Cohort baseline examination, comprising 101,723 participants. Variables considered in the analyses were self-reported diagnosis of asthma, age at first diagnosis, asthma treatment in the past 12 months, age, and sex. RESULTS: In the midterm dataset, 8.7% of women and 7.0% of men in the German National Cohort reported that they had ever been diagnosed with asthma. Approximately one third of participants with asthma received their initial diagnosis before their 18th birthday. COA affected 2.2% of women and 2.8% of men, whereas AOA affected 6.5% of women and 4.2% of men. During the previous 12 months, 33% of COA cases and 60% of AOA cases were medically treated. CONCLUSION: The proportion of persons affected by asthma in the German National Cohort, as well as observed patterns regarding age and gender, corresponds to other data sources such as DEGS. However, in our analysis, the proportion of individuals with AOA was higher than described in the literature. The increase in cumulative asthma diagnoses with age is markedly steeper in younger participants, indicating a rising trend over time.

[Assessment of self-reported cardiovascular and metabolic diseases in the German National Cohort (GNC, NAKO Gesundheitsstudie): methods and initial results]. / Erfassung selbst berichteter kardiovaskulärer und metabolischer Erkrankungen in der NAKO Gesundheitsstudie: Methoden und erste Ergebnisse.

BACKGROUND: Data on self-reported cardiovascular and metabolic diseases are available for the first 100,000 participants of the population-based German National Cohort (GNC, NAKO Gesundheitsstudie). OBJECTIVES: To describe assessment methods and the frequency of self-reported cardiovascular and metabolic diseases in the German National Cohort. MATERIALS AND METHODS: Using a computer-based, standardized personal interview, 101,806 participants (20-75 years, 46% men) from 18 nationwide study centres were asked to use a predefined list to report medical conditions ever diagnosed by a physician, including cardiovascular or metabolic diseases. For the latter, we calculated sex-stratified relative frequencies and compared these with reference data. RESULTS: With regard to cardiovascular diseases, 3.5% of men and 0.8% of women reported to have ever been diagnosed with a myocardial infarction, 4.8% and 1.5% with angina pectoris, 3.5% and 2.5% with heart failure, 10.1% and 10.4% with cardiac arrhythmia, 2.7% and 1.8% with claudicatio intermittens, and 34.6% and 27.0% with arterial hypertension. The frequencies of self-reported diagnosed metabolic diseases were 8.1% and 5.8% for diabetes mellitus, 28.6% and 24.5% for hyperlipidaemia, 7.9% and 2.4% for gout, and 10.1% and 34.3% for thyroid diseases. Observed disease frequencies were lower than reference data for Germany. CONCLUSIONS: In the German National Cohort, self-reported cardiovascular and metabolic diseases diagnosed by a physician are assessed from all participants, therefore representing a data source for future cardio-metabolic research in this cohort.

[Lung function in the German National Cohort: methods and initial results]. / Lungenfunktion in der NAKO Gesundheitsstudie: Methoden und erste Ergebnisse.

BACKGROUND: A nationwide assessment of the respiratory status on the basis of standardized lung function measurements has so far not been available in Germany. The present work describes the lung function tests in the German National Cohort (GNC) and presents initial results based on the GNC Midterm Baseline Dataset. MATERIAL AND METHODS: The assessment of lung function in the GNC comprised spirometry (level 1) and the determination of exhaled nitric oxide (FeNO, level 2). Our quality assurance concept included regular training of lung function test procedures at various GNC sites, interim evaluations of test quality, as well as regular calibration/measurement checks of test equipment. For spirometry, we established a stepwise procedure for offline quality control based on raw flow volume curves. RESULTS: In the present dataset (n = 101,734), spirometry was available for 86,893 study participants and FeNO was available for 15,228 participants. The average (±SD) FEV1 Z score (according to GLI 2012) was -0.321 ± 1.047, the FVC Z score was -0.153 ± 0.941, and the FEV1/FVC Z score was -0.337 ± 0.901. The difference in FEV1/FVC between current smokers and never-smokers increased with age. The average FeNO was 14.2 ÷ 2.0 ppb. Current smoking reduced FeNO levels by 43%, whereas respiratory allergy increased FeNO levels by 16% in nonsmokers. DISCUSSION: The results of spirometry and the FeNO measurements are in the expected range with regard to their distributions and correlates. The GNC provides a valuable basis for future investigations of respiratory health and its determinants as well as research into the prevention of respiratory diseases in Germany.

[Socio-demographic and employment-related factors in the German National Cohort (GNC; NAKO Gesundheitsstudie)]. / Soziodemografische und erwerbsbezogene Merkmale in der NAKO Gesundheitsstudie.

BACKGROUND: In epidemiologic studies, standardised measurement of socio-demographic and employment-related factors is becoming increasingly important, as variables such as gender, age, education or employment status are factors influencing health and disease risks. AIMS: The article gives an overview of the scientific background and assessment of socio-demographic factors in the German National Cohort Study. In addition, the distribution of individual characteristics in the cohort as well as relationships with health-related measures are presented by way of example. MATERIAL AND METHODS: The analysis is based on the data of the first half of the baseline survey (n = 101,724). On this basis, we present the distribution of key socio-demographic characteristics and analyse relationships with exemplary selected health indicators (body mass index, self-reported health) to assess the validity of socio-demographic data measurements. RESULTS: On average, study participants were 52.0 years old (SD = 12.4). Of the participants, 53.6% were women, 54.3% had high education, 60.1% were married and 72% were employed while 3.4% were unemployed. Well-established correlations between socio-demographic factors and health could be reproduced with the German National Cohort data. For example, low education, old age and unemployment were associated with an increased prevalence of obesity and poor self-reported health. DISCUSSION: The German National Cohort provides a comprehensive measurement of socio-demographic characteristics. Combined with a wide range of health data and the longitudinal measurements available in the future, this opens up new opportunities for health science and social epidemiological research in Germany.

[Self-reported cancer in the German National Cohort (NAKO Gesundheitsstudie): assessment methods and first results]. / Selbstberichtete Krebserkrankungen in der NAKO Gesundheitsstudie: Erfassungsmethoden und erste Ergebnisse.

BACKGROUND: In the German National Cohort (NAKO Gesundheitsstudie), the largest prospective cohort study in Germany, data on self-reported cancer diagnoses are now available for the first half of participants. OBJECTIVES: Description of the methods to assess self-reported cancer diagnoses and type of cancer in the NAKO and presentation of first results. MATERIALS AND METHODS: In a computer-assisted, standardized personal interview, 101,787 participants (54,526 women, 47,261 men) were asked whether they had ever been diagnosed with cancer (malignant tumors including in situ) by a physician and how many cancer diagnoses they had. The type of cancer was classified with a list. Absolute and relative frequencies of self-reported cancer diagnoses and types of cancer were calculated and compared with cancer registry data. RESULTS: A physician-diagnosed cancer was reported by 9.4% of women and 7.0% of men. Of the participants who reported a cancer diagnosis, 88.3% reported to have had only one cancer diagnosis. In women, the most frequent malignancies were breast cancer, cervical cancer, and melanoma. In men, the most frequent malignancies were prostate cancer, melanoma, and colorectal cancer. Comparing the frequencies of cancer diagnoses reported by 45- to 74-year-old NAKO participants within the last five years to cancer registry-based 5­year prevalences, most types of cancer were less frequent in the NAKO, with the exception of melanoma in men and women, cervical cancer and liver cancer in women, and bladder cancer and breast cancer in men. CONCLUSIONS: The NAKO is a rich data basis for future investigations of incident cancer.

[Measuring physical fitness in the German National Cohort-methods, quality assurance, and first descriptive results]. / Messung der körperlichen Fitness in der NAKO Gesundheitsstudie ­ Methoden, Qualitätssicherung und erste deskriptive Ergebnisse.

Physical fitness is defined as an individual's ability to be physically active. The main components are cardiorespiratory fitness (CRF), muscle strength, and flexibility. Regardless of physical activity level, physical fitness is an important determinant of morbidity and mortality.The aim of the current study was to describe the physical fitness assessment methodology in the German National Cohort (NAKO) and to present initial descriptive results in a subsample of the cohort.In the NAKO, hand grip strength (GS) and CRF as physical fitness components were assessed at baseline using a hand dynamometer and a submaximal bicycle ergometer test, respectively. Maximum oxygen uptake (VO2max) was estimated as a result of the bicycle ergometer test. The results of a total of 99,068 GS measurements and 3094 CRF measurements are based on a data set at halftime of the NAKO baseline survey (age 20-73 years, 47% men).Males showed higher values of physical fitness compared to women (males: GS = 47.8 kg, VO2max = 36.4 ml·min-1 · kg-1; females: GS = 29.9 kg, VO2max = 32.3 ml · min-1 · kg-1). GS declined from the age of 50 onwards, whereas VO2max levels decreased continuously between the age groups of 20-29 and ≥60 years. GS and VO2max showed a linear positive association after adjustment for body weight (males ß = 0.21; females ß = 0.35).These results indicate that the physical fitness measured in the NAKO are comparable to other population-based studies. Future analyses in this study will focus on examining the independent relations of GS and CRF with risk of morbidity and mortality.

[Self-reported infections in the German National Cohort (GNC) in the context of the current research landscape]. / Selbst berichtete Infektionen in der NAKO Gesundheitsstudie ­ Einordnung in die gegenwärtige Forschungslandschaft.

BACKGROUND: Infectious diseases continue to play an important role for disease perception, health-economic considerations and public health in Germany. In recent years, infectious diseases have been linked to the development of non-communicable diseases. Analyses of the German National Cohort (GNC) may provide deeper insights into this issue and pave the way for new targeted approaches in disease prevention. OBJECTIVES: The aim was to describe the tools used to assess infectious diseases and to present initial data on infectious disease frequencies, as well as to relate the GNC assessment tools to data collection methods in other studies in Germany. METHODS: As part of the baseline examination, questions regarding infectious diseases were administered using both an interview and a self-administered touchscreen questionnaire. Data from the initial 101,787 GNC participants were analysed. RESULTS: In the interview, 0.2% (HIV/AIDS) to 8.6% (shingles) of respondents reported ever having a medical diagnosis of shingles, postherpetic neuralgia (in cases where shingles was reported), hepatitis B/C, HIV/AIDS, tuberculosis or sepsis if treated in hospital. In the questionnaire, 12% (cystitis) to 81% (upper respiratory tract infections) of respondents reported having experienced at least one occurrence of upper or lower respiratory tract infections, gastrointestinal infections, cystitis or fever within the past 12 months. OUTLOOK: The cross-sectional analyses of data and tools presented here - for example on determinants of susceptibility to self-reported infections - can be anticipated from the year 2021 onward. Beyond that, more extensive research into infectious disease epidemiology will follow, particularly once analyses of GNC biological materials have been performed.

[Frequencies of musculoskeletal symptoms and disorders in the population-based German National Cohort (GNC)]. / Häufigkeiten muskuloskelettaler Symptome und Erkrankungen in der bevölkerungsbezogenen NAKO Gesundheitsstudie.

BACKGROUND: Musculoskeletal diseases and symptoms are very common in the general population. They lead to high healthcare costs and pose a significant burden to the national economy. OBJECTIVES: Based on data from the population-based German National Cohort (GNC), frequencies of musculoskeletal symptoms and diseases are reported, including back pain, osteoporosis, osteoarthritis, and arthritis. MATERIALS AND METHODS: Data were collected from March 2014 to March 2017 in adults aged 20-75 years during the first half of the baseline survey of the GNC. The sample comprised 101,779 interviewed subjects, including 9370 subjects who underwent clinical musculoskeletal examinations. The interview included questions about specific musculoskeletal disorders. A clinical examination of the hand provided information about palpable swollen joints and pressure-sensitive joints. Resting pain of the knees and hips was also assessed by a clinical examination. Frequencies were standardized to the German standard population of the year 2011. RESULTS: Having ever been diagnosed with recurrent back pain (22.5%) or osteoarthritis (20.6%) were the most common complaints reported in the interview; osteoporosis (2.9%) and rheumatoid arthritis (1.9%) were stated more seldom. According to the hand examination, 6.0% of all participants experienced pain in at least one finger joint. Resting pain was present in at least one knee among 8.2% and in at least one hip among 5.1% of the participants as assessed during the clinical examination. Women were more likely to report musculoskeletal disorders and symptoms than men. The proportion of adults affected by musculoskeletal diseases increased strongly with age. CONCLUSION: Musculoskeletal disorders and symptoms occur frequently. The burden of complaints and diagnoses is comparable to previous population-based surveys.

[Design and quality control of the oral health status examination in the German National Cohort (GNC)]. / Design und Qualitätskontrolle der zahnmedizinischen Untersuchung in der NAKO Gesundheitsstudie.

BACKGROUND: Caries and periodontitis are highly prevalent worldwide. Because detailed data on these oral diseases were collected within the framework of the German National Cohort (GNC), associations between oral and systemic diseases and conditions can be investigated. OBJECTIVES: The study protocol for the oral examination was designed to ensure a comprehensive collection of dental findings by trained non-dental staff within a limited examination time. At the mid-term of the GNC baseline examination, a first quality evaluation was performed to check the plausibility of results and to propose measures to improve the data quality. MATERIALS AND METHODS: A dental interview, saliva sampling and oral diagnostics were conducted. As part of the level­1 examination, the number of teeth and prostheses were recorded. As part of the level­2 examination, detailed periodontal, cariological and functional aspects were examined. All examinations were conducted by trained non-dental personnel. Parameters were checked for plausibility and variable distributions were descriptively analysed. RESULTS: Analyses included data of 57,967 interview participants, 56,913 level­1 participants and 6295 level­2 participants. Percentages of missing values for individual clinical parameters assessed in level 1 and level 2 ranged between 0.02 and 3.9%. Results showed a plausible distribution of the data; rarely, implausible values were observed, e.g. for measurements of horizontal and vertical overbite (overjet and overbite). Intra-class correlation coefficients indicated differences in individual parameters between regional clusters, study centres and across different examiners. CONCLUSIONS: The results confirm the feasibility of the study protocol by non-dental personnel and its successful integration into the GNC's overall assessment program. However, rigorous dental support of the study centres is required for quality management.

[Physical activity in the German National Cohort (NAKO): use of multiple assessment tools and initial results]. / Körperliche Aktivität in der NAKO Gesundheitsstudie: erste Ergebnisse des multimodalen Erhebungskonzepts.

BACKGROUND: Physical activity is a complex behavior that is difficult to measure validly and reliably in large, population-based studies. Data on physical activity are available for the initial 100,000 participants of the German National Cohort. OBJECTIVES: To describe the baseline physical activity assessment in the cohort and to present initial descriptive results. MATERIAL AND METHODS: Physical activity was assessed using a combination of tools, including two self-administered questionnaires, the Questionnaire on Annual Physical Activity Pattern (QUAP) and the Global Physical Activity Questionnaire (GPAQ); a computer-based 24­h physical activity recall (cpar24); and 7­day accelerometry (Actigraph GT3X/+; ActiGraph, Pensacola, FL, USA). RESULTS: The availability of data varied between assessment instruments (QUAP: n = 16,372; GPAQ: n = 90,900; cpar24: n = 23,989; accelerometry: n = 35,218). Analyses across measurement tools showed that on average, women spent 75 to 216 min/d, and men spent 73 to 224 min/d in moderate or higher intensity total physical activity. Persons aged 20-39 years spent 66 to 200 min/d, and persons aged 40-69 years spent 78 to 244 min/d in moderate or higher intensity total physical activity. CONCLUSIONS: Initial baseline analyses of physical activity in this cohort show the value of using a combination of questionnaires, 24­h recalls, and a movement sensor. The comprehensive data collection represents a valuable resource for future analyses and will improve our understanding of the association between physical activity and disease prevention.

[Nighttime transportation noise annoyance in Germany: personal and regional differences in the German National Cohort Study]. / Nächtliche Verkehrslärmbelästigung in Deutschland: individuelle und regionale Unterschiede in der NAKO Gesundheitsstudie.

BACKGROUND: Noise annoyance is associated with adverse health-related conditions and reduced wellbeing. Thereby, subjective noise annoyance depends on the objective noise exposure and is modified by personal and regional factors. OBJECTIVE: How many participants of the German National Cohort Study (GNC; NAKO Gesundheitsstudie) were annoyed by transportation noise during nighttime and what factors were associated with noise annoyance? MATERIALS AND METHODS: This cross-sectional analysis included 86,080 participants from 18 study centers, examined from 2014 to 2017. We used multinomial logistic regression to investigate associations of personal and regional factors to noise annoyance (slightly/moderately or strongly/extremely annoyed vs. not annoyed) mutually adjusting for all factors in the model. RESULTS: Two thirds of participants were not annoyed by transportation noise during nighttime and one in ten reported strong/extreme annoyance with highest percentages for the study centers Berlin-Mitte and Leipzig. The strongest associations were seen for factors related to the individual housing situation like the bedroom being positioned towards a major road (OR of being slightly/moderately annoyed: 4.26 [95% CI: 4.01;4.52]; OR of being strongly/extremely annoyed: 13.36 [95% CI: 12.47;14.32]) compared to a garden/inner courtyard. Participants aged 40-60 years and those in low- and medium-income groups reported greater noise annoyance compared to younger or older ones and those in the high-income group. CONCLUSION: In this study from Germany, transportation noise annoyance during nighttime varied by personal and regional factors.

[The baseline assessment of the German National Cohort (NAKO Gesundheitsstudie): participation in the examination modules, quality assurance, and the use of secondary data]. / Die Basiserhebung der NAKO Gesundheitsstudie: Teilnahme an den Untersuchungsmodulen, Qualitätssicherung und Nutzung von Sekundärdaten.

BACKGROUND: The German National Cohort (NAKO) is an interdisciplinary health study aimed at elucidating causes for common chronic diseases and detecting their preclinical stages. This article provides an overview of design, methods, participation in the examinations, and their quality assurance based on the midterm baseline dataset (MBD) of the recruitment. METHODS: More than 200,000 women and men aged 20-69 years derived from random samples of the German general population were recruited in 18 study centers (2014-2019). The data collection comprised physical examinations, standardized interviews and questionnaires, and the collection of biomedical samples for all participants (level 1). At least 20% of all participants received additional in-depth examinations (level 2), and 30,000 received whole-body magnet resonance imaging (MRI). Additional information will be collected through secondary data sources such as medical registries, health insurances, and pension funds. This overview is based on the MBD, which included 101,839 participants, of whom 11,371 received an MRI. RESULTS: The mean response proportion was 18%. The participation in the examinations was high with most of the modules performed by over 95%. Among MRI participants, 96% completed all 12 MRI sequences. More than 90% of the participants agreed to the use of complementary secondary and registry data. DISCUSSION: Individuals selected for the NAKO were willing to participate in all examinations despite the time-consuming program. The NAKO provides a central resource for population-based epidemiologic research and will contribute to developing innovative strategies for prevention, screening and prediction of chronic diseases.

[Anthropometric measures in the German National Cohort-more than weight and height]. / Anthropometrische Messungen in der NAKO Gesundheitsstudie ­ mehr als nur Größe und Gewicht.

High levels of adiposity in the population have a major impact on various diseases, but previous epidemiologic studies have largely been restricted to simple anthropometric measures such as the body mass index (BMI), an imperfect predictor of disease risk. There is a critical need for the use of improved measures of relative weight and body composition in large-scale, population-based research.The current article presents initial descriptive results of body composition and fat distribution based on the midterm baseline dataset of the German National Cohort, which included 101,817 participants who were examined in 18 study centers in Germany between March 2014 and March 2017. The anthropometric measures encompassed body weight, height, waist and hip circumference, bioelectrical impedance analysis (BIA), sonography of abdominal adipose tissue, 3D-body scanning, and magnetic resonance imaging.BMI analyses showed that 46.2% of men and 29.7% of women were overweight and 23.5% of men and 21.2% of women were obese. On average, women in almost all age groups demonstrated more subcutaneous adipose tissue layer thickness than men. The mean values of visceral adipose tissue layer thickness, on the other hand, were higher among men than among women in all age groups and increased continuously across age groups in both sexes.The comprehensive assessment of body composition and fat distribution provides novel future opportunities for detailed epidemiologic analyses of overweight and adiposity in relation to the development of chronic diseases.

Amino acid duplication in the coiled-coil structure of collagen XVII alters its maturation and trimerization causing mild junctional epidermolysis bullosa.

The function and stability of collagens depend on the accurate triple helix formation of three distinct polypeptide chains. Disruption of this triple-helical structure can result in connective-tissue disorders. Triple helix formation is thought to depend on three-stranded coiled-coil oligomerization sites within non-collagenous domains. However, only little is known about the physiological relevance of these coiled-coil structures. Transmembrane collagen XVII, also known as 180 kDa bullous pemphigoid antigen provides mechanical stability through the anchorage of epithelial cells to the basement membrane. Mutations in the collagen XVII gene, COL17A1, cause junctional epidermolysis bullosa (JEB), characterized by chronic trauma-induced skin blistering. Here we exploited a novel naturally occurring COL17A1 mutation, leading to an in-frame lysine duplication within the coiled-coil structure of the juxtamembranous NC16A domain of collagen XVII, which resulted in a mild phenotype of JEB due to reduced membrane-anchored collagen XVII molecules. This mutation causes structural changes in the mutant molecule and interferes with its maturation. The destabilized coiled-coil structure of the mutant collagen XVII unmasks a furin cleavage site that results in excessive and non-physiological ectodomain shedding during its maturation. Furthermore, it decreases its triple-helical stability due to defective coiled-coil oligomerization, which makes it highly susceptible to proteolytic degradation. As a consequence of altered maturation and decreased stability of collagen XVII trimers, reduced collagen XVII is incorporated into the cell membrane, resulting in compromised dermal-epidermal adhesion. Taken together, using this genetic model, we provide the first proof that alteration of the coiled-coil structure destabilizes oligomerization and impairs physiological shedding of collagen XVII in vivo.

Targeting of Cell Surface Proteolysis of Collagen XVII Impedes Squamous Cell Carcinoma Progression.

Squamous cell carcinoma (SCC) is one of the most common skin cancers and causes significant morbidity. Although the expression of the epithelial adhesion molecule collagen XVII (ColXVII) has been linked to SCC invasion, only little is known about its mechanistic contribution. Here, we demonstrate that ColXVII expression is essential for SCC cell proliferation and motility. Moreover, it revealed that particularly the post-translational modification of ColXVII by ectodomain shedding is the major driver of SCC progression, because ectodomain-selective immunostaining was mainly localized at the invasive front of human cutaneous SCCs, and exclusive expression of a non-sheddable ColXVII mutant in SCC-25 cells inhibits their matrix-independent growth and invasiveness. This cell surface proteolysis, which is strongly elevated during SCC invasion and metastasis, releases soluble ectodomains and membrane-anchored endodomains. Both released ColXVII domains play distinct roles in tumor progression: the endodomain induces proliferation and survival, whereas the ectodomain accelerates invasiveness. Furthermore, specific blockage of shedding by monoclonal ColXVII antibodies repressed matrix-independent growth and invasion of SCC cells in organotypic co-cultures. Thus, selective inhibition of ColXVII shedding may offer a promising therapeutic strategy to prevent SCC progression.

Skin Barrier Defects Caused by Keratinocyte-Specific Deletion of ADAM17 or EGFR Are Based on Highly Similar Proteome and Degradome Alterations.

Keratinocyte-specific deletion of ADAM17 in mice impairs terminal differentiation of keratinocytes leading to severe epidermal barrier defects. Mice deficient for ADAM17 in keratinocytes phenocopy mice with a keratinocyte-specific deletion of epidermal growth factor receptor (EGFR), which highlights the role of ADAM17 as a "ligand sheddase" of EGFR ligands. In this study, we aim for the first proteomic/degradomic approach to characterize the disruption of the ADAM17-EGFR signaling axis and its consequences for epidermal barrier formation. Proteomic profiling of the epidermal proteome of mice deficient for either ADAM17 or EGFR in keratinocytes at postnatal days 3 and 10 revealed highly similar protein alterations for ADAM17 and EGFR deficiency. These include massive proteome alterations of structural and regulatory components important for barrier formation such as transglutaminases, involucrin, filaggrin, and filaggrin-2. Cleavage site analysis using terminal amine isotopic labeling of substrates revealed increased proteolytic processing of S100 fused-type proteins including filaggrin-2. Alterations in proteolytic processing are supported by altered abundance of numerous proteases upon keratinocyte-specific Adam17 or Egfr deletion, among them kallikreins, cathepsins, and their inhibitors. This study highlights the essential role of proteolytic processing for maintenance of a functional epidermal barrier. Furthermore, it suggests that most defects in formation of the postnatal epidermal barrier upon keratinocyte-specific ADAM17 deletion are mediated via EGFR.

Tension in Cancer.

Integrins represent a large family of cell receptors that mediate adhesion to the extracellular matrix (ECM), thereby modulating a variety of cellular functions that are required for proliferation, migration, malignant conversion and invasiveness. During tumorigenesis the conversion of a tumor cell from sessile, stationary phenotype to an invasive phenotype requires the ability of tumor cells to interact with their environment in order to transduce signals from the ECM into the cells. Hence, there is increasing evidence that changes in the composition, topography and tension of tumor matrix can be sensed by integrin receptors, leading to the regulation of intracellular signalling events which subsequently help to fuel cancer progression. The fact that intracellular signals perceived from integrin ligand binding impact on almost all steps of tumor progression, including tumor cell proliferation, survival, metastatic dissemination and colonization of a metastatic niche, renders integrins as ideal candidates for the development of therapeutic agents. In this review we summarize the role of integrins in cancer with the special focus on cancer therapies and the recent progress that has been made in the understanding of "integrin-induced tension in cancer". Finally, we conclude with clinical evidence for the role of integrin-mediated mechanotransduction in the development of therapy-resistant tumors.