The Vinculin-ΔIn20/21 Mouse: Characteristics of a Constitutive, Actin-Binding Deficient Splice Variant of Vinculin

BACKGROUND: The cytoskeletal adaptor protein vinculin plays a fundamental role in cell contact regulation and affects central aspects of cell motility, which are essential to both embryonal development and tissue homeostasis. Functional regulation of this evolutionarily conserved and ubiquitously expressed protein is dominated by a high-affinity, autoinhibitory head-to-tail interaction that spatially restricts ligand interactions to cell adhesion sites and, furthermore, limits the residency time of vinculin at these sites. To date, no mutants of the vinculin protein have been characterized in animal models. METHODOLOGY/PRINCIPAL FINDINGS: Here, we investigate vinculin-DeltaEx20, a splice variant of the protein lacking the 68 amino acids encoded by exon 20 of the vinculin gene VCL. Vinculin-DeltaEx20 was found to be expressed alongside with wild type protein in a knock-in mouse model with a deletion of introns 20 and 21 (VCL-DeltaIn20/21 allele) and shows defective head-to-tail interaction. Homozygous VCL-DeltaIn20/21 embryos die around embryonal day E12.5 showing cranial neural tube defects and exencephaly. In mouse embryonic fibroblasts and upon ectopic expression, vinculin-DeltaEx20 reveals characteristics of constitutive head binding activity. Interestingly, the impact of vinculin-DeltaEx20 on cell contact induction and stabilization, a hallmark of the vinculin head domain, is only moderate, thus allowing invasion and motility of cells in three-dimensional collagen matrices. Lacking both F-actin interaction sites of the tail, the vinculin-DeltaEx20 variant unveils vinculin's dynamic binding to cell adhesions independent of a cytoskeletal association, and thus differs from head-to-tail binding deficient mutants such as vinculin-T12, in which activated F-actin binding locks the protein variant to cell contact sites. CONCLUSIONS/SIGNIFICANCE: Vinculin-DeltaEx20 is an active variant supporting adhesion site stabilization without an enhanced mechanical coupling. Its presence in a transgenic animal reveals the potential of splice variants in the vinculin gene to alter vinculin function in vivo. Correct control of vinculin is necessary for embryonic development

20 Years of Pediatric Benchmarking in Germany and Austria: Age-Dependent Analysis of Longitudinal Follow-Up in 63,967 Children and Adolescents with Type 1 Diabetes

To investigate changes in diabetes treatment over the last two decades in three age-groups of children and adolescents with type 1 diabetes (T1D) from Germany and Austria.63,967 subjects (<18yr) with T1D documented between 1995 and 2014 from the DPV-database were included and stratified according to age (0.5-<6, 6-<12, 12-<18yr). Regression models were applied for insulin regimens (<3 and ≥4 injection time points/day, or continuous subcutaneous insulin infusion (CSII)), use of rapid- and long acting insulin analogues, NPH insulin, and frequency of self-monitoring of blood glucose (SMBG)/day. Models were adjusted for sex, diabetes duration, and migration background. P-value for trend was given.The number of subjects with <3 injection time points/day decreased from 1995 to 2014 to <5% in all age-groups (p<0.0001). Proportion of patients with ≥4 injections/day increased until the early 2000s, and then declined until 2014. This trend was not found in 6-<12yr olds (p = 0.3403). CSII increased in all age-groups (p<0.0001) with the highest increase in children <6 years (from 0.4% to 79.2%), and the lowest increase in 12-<18 year olds (from 1.0% to 38.9%). NPH insulin decreased in all age-groups (p<0.0001). Insulin analogues, especially rapid-acting, became more frequent in all age-groups (p<0.0001), accounting for 78.4% in 2014 for all subjects. The highest use was found in the youngest children (in 2014: 85.6%), the lowest use in 6-<12 year olds (in 2014: 72.9%). The number of SMBG/day increased from 2.2 to 6.4 with a similar rise in all age-groups (p<0.0001). Frequency was highest in subjects <6yr.In all age-groups, T1D treatment was intensified over the last 20 years. Age-specific differences in trends were particularly observed in the number of patients on CSII, in the number of patients with 4 or more injections/day, and in the frequency of SMBG/day

Hospitalization in pediatric diabetes : a nationwide analysis of all admission causes for Germany in 2015

Introduction Regarding pediatric diabetes, hospital admission for acute complications of type 1 diabetes (T1D) has often been investigated, but little is known about other causes of hospitalization. This study aimed to explore the total burden of hospitalization in individuals with diabetes <20 years of age in Germany. Methods Using the German Diagnosis-Related Groups data for 2015, we examined the frequencies of hospitalization with diabetes (20,251 inpatient cases), stratified by diabetes type [T1D, type 2 diabetes (T2D), other specified diabetes types (T3D), and unclear diabetes], and without diabetes (1,269,631 inpatient cases). Using estimates of the population at risk with T1D, T2D, and without diabetes, we evaluated hospitalization rates (per patient-year) by Poisson regression. For T1D, T2D, and T3D, we investigated the most frequent diagnoses and the median length of stay. Most analyses were stratified by sex, age-group and east/west residence. Results Children and adolescents with diabetes had a 6 to 9 times higher hospitalization risk than peers without diabetes (hospitalization rate 0.09). The hospitalization rate was higher for T2D compared with T1D (0.84 vs. 0.53, P<0.001). In T2D, two-third of inpatient cases were not directly related to diabetes, and stay was shorter compared with T1D and T3D (3 vs. 4 and 5 days, respectively). In T1D, hospitalization was more frequent among girls than boys (0.58 vs. 0.49, P<0.001), and mostly due to “diabetes without complications” (65.7%). Hospitalization tended to be more frequent and longer in the youngest patients, and in those with east residence. Conclusion Hospitalization rate in pediatric diabetes in Germany remained high, especially for T2D patients, girls with T1D, and young children

E-cadherin integrates mechanotransduction and EGFR signaling to control junctional tissue polarization and tight junction positioning

Generation of a barrier in multi-layered epithelia like the epidermis requires restricted positioning of functional tight junctions (TJ) to the most suprabasal viable layer. This positioning necessitates tissue-level polarization of junctions and the cytoskeleton through unknown mechanisms. Using quantitative whole-mount imaging, genetic ablation, and traction force microscopy and atomic force microscopy, we find that ubiquitously localized E-cadherin coordinates tissue polarization of tension-bearing adherens junction (AJ) and F-actin organization to allow formation of an apical TJ network only in the uppermost viable layer. Molecularly, E-cadherin localizes and tunes EGFR activity and junctional tension to inhibit premature TJ complex formation in lower layers while promoting increased tension and TJ stability in the granular layer 2. In conclusion, our data identify an E-cadherin-dependent mechanical circuit that integrates adhesion, contractile forces and biochemical signaling to drive the polarized organization of junctional tension necessary to build an in vivo epithelial barrier

Sociodemographic and clinical characteristics of all subjects included and stratified according to age-groups.

<p>Sociodemographic and clinical characteristics of all subjects included and stratified according to age-groups.</p

Selection of study population.

<p>Selection of study population.</p