Matriptase-2, a serine protease expressed in hepatocytes, is a negative regulator of hepcidin expression. The purpose of the study was to investigate the interaction of matriptase-2 with hemojuvelin protein in vivo. Mice lacking the matriptase-2 proteolytic activity (mask mice) display decreased content of hemojuvelin protein. Vice versa, the absence of hemojuvelin results in decreased liver content of matriptase-2, indicating that the two proteins interact. To further characterize the role of matriptase-2, we investigated iron metabolism in mask mice fed experimental diets. Administration of iron-enriched diet increased liver iron stores as well as hepcidin expression. Treatment of iron-overloaded mask mice with erythropoietin increased hemoglobin and hematocrit, indicating that the response to erythropoietin is intact in mask mice. Feeding of an iron-deficient diet to mask mice significantly increased spleen weight as well as the splenic content of erythroferrone and transferrin receptor proteins, indicating stress erythropoiesis. Liver hepcidin expression was decreased; expression of Id1 was not changed. Overall, the results suggest a complex interaction between matriptase-2 and hemojuvelin, and demonstrate that hepcidin can to some extent be regulated even in the absence of matriptase-2 proteolytic activity.

• MeSH
• Iron Deficiencies MeSH
• Iron, Dietary pharmacology   MeSH
• Erythropoietin pharmacology   MeSH
• GPI-Linked Proteins biosynthesis   deficiency   genetics   physiology   MeSH
• Hepcidins biosynthesis   genetics   MeSH
• Inhibitor of Differentiation Protein 1 biosynthesis   genetics   MeSH
• Liver metabolism   MeSH
• Bone Morphogenetic Protein 6 biosynthesis   genetics   MeSH
• Membrane Proteins deficiency   genetics   physiology   MeSH
• Mice, Inbred C57BL MeSH
• Mice, Knockout MeSH
• Mice MeSH
• Organ Specificity MeSH
• Iron Overload metabolism   MeSH
• Promoter Regions, Genetic genetics   MeSH
• Hemochromatosis Protein biosynthesis   deficiency   genetics   physiology   MeSH
• Protein Domains MeSH
• Gene Expression Regulation drug effects   MeSH
• Recombinant Proteins metabolism   MeSH
• Serine Endopeptidases deficiency   genetics   physiology   MeSH
• Spleen metabolism   MeSH
• Iron MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

The systemic anaphylactic reaction is a life-threatening allergic response initiated by activated mast cells. Sphingolipids are an essential player in the development and attenuation of this response. De novo synthesis of sphingolipids in mammalian cells is inhibited by the family of three ORMDL proteins (ORMDL1, 2, and 3). However, the cell and tissue-specific functions of ORMDL proteins in mast cell signaling are poorly understood. This study aimed to determine cross-talk of ORMDL2 and ORMDL3 proteins in IgE-mediated responses. To this end, we prepared mice with whole-body knockout (KO) of Ormdl2 and/or Ormdl3 genes and studied their role in mast cell-dependent activation events in vitro and in vivo. We found that the absence of ORMDL3 in bone marrow-derived mast cells (BMMCs) increased the levels of cellular sphingolipids. Such an increase was further raised by simultaneous ORMDL2 deficiency, which alone had no effect on sphingolipid levels. Cells with double ORMDL2 and ORMDL3 KO exhibited increased intracellular levels of sphingosine-1-phosphate (S1P). Furthermore, we found that concurrent ORMDL2 and ORMDL3 deficiency increased IκB-α phosphorylation, degranulation, and production of IL-4, IL-6, and TNF-α cytokines in antigen-activated mast cells. Interestingly, the chemotaxis towards antigen was increased in all mutant cell types analyzed. Experiments in vivo showed that passive cutaneous anaphylaxis (PCA), which is initiated by mast cell activation, was increased only in ORMDL2,3 double KO mice, supporting our in vitro observations with mast cells. On the other hand, ORMDL3 KO and ORMDL2,3 double KO mice showed faster recovery from passive systemic anaphylaxis, which could be mediated by increased levels of blood S1P presented in such mice. Our findings demonstrate that Ormdl2 deficiency potentiates the ORMDL3-dependent changes in mast cell signaling.

• MeSH
• Anaphylaxis etiology   metabolism   MeSH
• Biomarkers MeSH
• Chemotaxis immunology   MeSH
• Cytokines metabolism   MeSH
• Gene Expression MeSH
• Lysophospholipids blood   metabolism   MeSH
• Mast Cells immunology   metabolism   MeSH
• Membrane Proteins chemistry   deficiency   genetics   metabolism   MeSH
• Multigene Family MeSH
• Mice, Knockout MeSH
• Mice MeSH
• Disease Susceptibility MeSH
• Passive Cutaneous Anaphylaxis genetics   immunology   MeSH
• Amino Acid Sequence MeSH
• Sphingolipids blood   metabolism   MeSH
• Sphingosine analogs & derivatives   blood   metabolism   MeSH
• Signal Transduction * MeSH
• Calcium metabolism   MeSH
• Calcium Signaling MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

We studied how deficiency in lamins A/C and lamina-associated polypeptide 2α (Lap2α) affects DNA repair after irradiation. A-type lamins and Lap2α were not recruited to local DNA lesions and did not accumulate to γ-irradiation-induced foci (IRIF), as it is generally observed for well-known marker of DNA lesions, 53BP1 protein. At micro-irradiated chromatin of lmna double knockout (dn) and Lap2α dn cells, 53BP1 protein levels were reduced, compared to locally irradiated wild-type counterpart. Decreased levels of 53BP1 we also observed in whole populations of lmna dn and Lap2α dn cells, irradiated by UV light. We also studied distribution pattern of 53BP1 protein in a genome outside micro-irradiated region. In Lap2α deficient cells, identical fluorescence of mCherry-tagged 53BP1 protein was found at both microirradiated region and surrounding chromatin. However, a well-known marker of double strand breaks, γH2AX, was highly abundant in the lesion-surrounding genome of Lap2α deficient cells. Described changes, induced by irradiation in Lap2α dn cells, were not accompanied by cell cycle changes. In Lap2α dn cells, we additionally performed analysis by FLIM (Fluorescence Lifetime Imaging Microscopy) that showed different dynamic behavior of mCherry-tagged 53BP1 protein pools when it was compared with wild-type (wt) fibroblasts. This analysis revealed three different fractions of mCherry-53BP1 protein. Two of them showed identical exponential decay times (τ1 and τ3), but the decay rate of τ2 and amplitudes of fluorescence decays (A1-A3) were statistically different in wt and Lap2α dn fibroblasts. Moreover, γ-irradiation weakened an interaction between A-type lamins and Lap2α. Together, our results demonstrate how depletion of Lap2α affects DNA damage response (DDR) and how chromatin compactness is changed in Lap2α deficient cells exposed to radiation.

• MeSH
• Tumor Suppressor p53-Binding Protein 1 genetics   metabolism   MeSH
• Chromatin chemistry   radiation effects   ultrastructure   MeSH
• DNA-Binding Proteins deficiency   genetics   MeSH
• Embryo, Mammalian MeSH
• Fibroblasts cytology   metabolism   radiation effects   MeSH
• Fluorescence Recovery After Photobleaching MeSH
• Histones genetics   metabolism   MeSH
• Lamin Type A deficiency   genetics   MeSH
• Luminescent Proteins genetics   metabolism   MeSH
• Membrane Proteins deficiency   genetics   MeSH
• Mice MeSH
• DNA Repair * MeSH
• DNA Damage MeSH
• Gene Expression Regulation MeSH
• Recombinant Fusion Proteins genetics   metabolism   MeSH
• Genes, Reporter MeSH
• Signal Transduction MeSH
• Cell Line, Transformed MeSH
• Ultraviolet Rays MeSH
• Gamma Rays MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

• MeSH
• Acidosis, Lactic diagnosis   genetics   pathology   MeSH
• Gene Expression MeSH
• Facies MeSH
• Fatal Outcome MeSH
• Cardiomyopathy, Hypertrophic diagnosis   genetics   pathology   MeSH
• Hypospadias diagnosis   genetics   pathology   MeSH
• Humans MeSH
• Membrane Proteins deficiency   genetics   MeSH
• Microcephaly diagnosis   genetics   pathology   MeSH
• Mitochondrial Proteins deficiency   genetics   MeSH
• Mutation MeSH
• Child, Preschool MeSH
• Muscle Hypotonia diagnosis   genetics   pathology   MeSH
• Hernias, Diaphragmatic, Congenital diagnostic imaging   genetics   pathology   surgery   MeSH
• Developmental Disabilities diagnosis   genetics   pathology   MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Child, Preschool MeSH
• Publication type
• Letter MeSH
• Case Reports MeSH

The patterning of repeated structures is a major theme in developmental biology, and the inter-relationship between spacing and size of such structures is an unresolved issue. Fungiform papillae are repeated epithelial structures that house taste buds on the anterior tongue. Here, we report that FGF signaling is a crucial regulator of fungiform papillae development. We found that mesenchymal FGF10 controls the size of the papillary area, while overall patterning remains unchanged. Our results show that FGF signaling negatively affects the extent of canonical Wnt signaling, which is the main activation pathway during fungiform papillae development; however, this effect does not occur at the level of gene transcription. Rather, our experimental data, together with computational modeling, indicate that FGF10 modulates the range of Wnt effects, likely via induction of Sostdc1 expression. We suggest that modification of the reach of Wnt signaling could be due to local changes in morphogen diffusion, representing a novel mechanism in this tissue context, and we propose that this phenomenon might be involved in a broader array of mammalian developmental processes.

• MeSH
• Models, Biological MeSH
• Taste Buds embryology   metabolism   MeSH
• Fibroblast Growth Factor 10 deficiency   genetics   metabolism   MeSH
• Intracellular Signaling Peptides and Proteins deficiency   genetics   metabolism   MeSH
• Bone Morphogenetic Proteins genetics   metabolism   MeSH
• Membrane Proteins deficiency   genetics   metabolism   MeSH
• Mice, Knockout MeSH
• Mice, Transgenic MeSH
• Mice MeSH
• Computer Simulation MeSH
• Hedgehog Proteins genetics   metabolism   MeSH
• Body Patterning genetics   physiology   MeSH
• Wnt Signaling Pathway * MeSH
• Pregnancy MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Pregnancy MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

• MeSH
• Drug Resistance genetics   MeSH
• Humans MeSH
• Membrane Proteins * genetics   deficiency   MeSH
• Tumor Suppressor Proteins * genetics   deficiency   MeSH
• Ovarian Neoplasms * genetics   MeSH
• Antineoplastic Agents MeSH
• Endoplasmic Reticulum Stress genetics   MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• News MeSH

The role of the local microenvironment in influencing cell behavior is central to both normal development and cancer formation. Here, we show that sprouty 1 (SPRY1) modulates the microenvironment to enable proper mammary branching morphogenesis. This process occurs through negative regulation of epidermal growth factor receptor (EGFR) signaling in mammary stroma. Loss of SPRY1 resulted in up-regulation of EGFR-extracellular signal-regulated kinase (ERK) signaling in response to amphiregulin and transforming growth factor alpha stimulation. Consequently, stromal paracrine signaling and ECM remodeling is augmented, leading to increased epithelial branching in the mutant gland. By contrast, down-regulation of EGFR-ERK signaling due to gain of Sprouty function in the stroma led to stunted epithelial branching. Taken together, our results show that modulation of stromal paracrine signaling and ECM remodeling by SPRY1 regulates mammary epithelial morphogenesis during postnatal development.

• MeSH
• Adaptor Proteins, Signal Transducing deficiency   metabolism   MeSH
• Amphiregulin pharmacology   MeSH
• Stromal Cells drug effects   metabolism   MeSH
• Time-Lapse Imaging MeSH
• Epithelium growth & development   metabolism   MeSH
• Epithelial Cells cytology   drug effects   MeSH
• ErbB Receptors metabolism   MeSH
• Extracellular Matrix metabolism   MeSH
• Extracellular Signal-Regulated MAP Kinases metabolism   MeSH
• Fibroblasts drug effects   metabolism   MeSH
• Phosphoproteins deficiency   metabolism   MeSH
• Phosphorylation drug effects   MeSH
• Collagen metabolism   MeSH
• Ligands MeSH
• Membrane Proteins deficiency   metabolism   MeSH
• Mammary Glands, Animal drug effects   metabolism   MeSH
• Morphogenesis * drug effects   MeSH
• Mutation genetics   MeSH
• Mice, Knockout MeSH
• Mice, Nude MeSH
• Paracrine Communication * drug effects   MeSH
• Cell Movement drug effects   MeSH
• Proto-Oncogene Proteins c-akt metabolism   MeSH
• Signal Transduction * drug effects   MeSH
• Transforming Growth Factor alpha pharmacology   MeSH
• Gene Expression Regulation, Developmental drug effects   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH

UNLABELLED: A Disintegrin And Metalloprotease (ADAM) 10 exerts essential roles during organ development and tissue integrity in different organs, mainly through activation of the Notch pathway. However, only little is known about its implication in liver tissue physiology. Here we show that in contrast to its role in other tissues, ADAM10 is dispensable for the Notch2-dependent biliary tree formation. However, we demonstrate that expression of bile acid transporters is dependent on ADAM10. Consequently, mice deficient for Adam10 in hepatocytes, cholangiocytes and liver progenitor cells develop spontaneous hepatocyte necrosis and concomitant liver fibrosis. We furthermore observed a strongly augmented ductular reaction in 15-week old ADAM10(Δhep/Δch) mice and demonstrate that c-Met dependent liver progenitor cell activation is enhanced. Additionally, liver progenitor cells are primed to hepatocyte differentiation in the absence of ADAM10. These findings show that ADAM10 is a novel central node controlling liver tissue homeostasis. HIGHLIGHTS: Loss of ADAM10 in murine liver results in hepatocyte necrosis and concomitant liver fibrosis. ADAM10 directly regulates expression of bile acid transporters but is dispensable for Notch2-dependent formation of the biliary system. Activation of liver progenitor cells is enhanced through increased c-Met signalling, in the absence of ADAM10. Differentiation of liver progenitor cells to hepatocytes is augmented in the absence of ADAM10.

• MeSH
• Cell Differentiation physiology   MeSH
• Down-Regulation MeSH
• Hepatocytes metabolism   pathology   MeSH
• Homeostasis MeSH
• Liver cytology   metabolism   pathology   MeSH
• Membrane Glycoproteins metabolism   MeSH
• Membrane Proteins deficiency   genetics   metabolism   MeSH
• Mice, Knockout MeSH
• Mice, Transgenic MeSH
• Mice MeSH
• Necrosis MeSH
• Cell Proliferation physiology   MeSH
• ADAM10 Protein deficiency   genetics   metabolism   MeSH
• Receptor, Notch2 metabolism   MeSH
• Amyloid Precursor Protein Secretases deficiency   genetics   metabolism   MeSH
• Signal Transduction MeSH
• Carrier Proteins metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

TMEM70, a 21-kDa protein localized in the inner mitochondrial membrane, has been shown to facilitate the biogenesis of mammalian F1Fo ATP synthase. Mutations of the TMEM70 gene represent the most frequent cause of isolated ATP synthase deficiency resulting in a severe mitochondrial disease presenting as neonatal encephalo-cardiomyopathy (OMIM 604273). To better understand the biological role of this factor, we generated Tmem70-deficient mice and found that the homozygous Tmem70-/- knockouts exhibited profound growth retardation and embryonic lethality at ∼9.5 days post coitum. Blue-Native electrophoresis demonstrated an isolated deficiency in fully assembled ATP synthase in the Tmem70-/- embryos (80% decrease) and a marked accumulation of F1 complexes indicative of impairment in ATP synthase biogenesis that was stalled at the early stage, following the formation of F1 oligomer. Consequently, a decrease in ADP-stimulated State 3 respiration, respiratory control ratio and ATP/ADP ratios, indicated compromised mitochondrial ATP production. Tmem70-/- embryos exhibited delayed development of the cardiovascular system and a disturbed heart mitochondrial ultrastructure, with concentric or irregular cristae structures. Tmem70+/- heterozygous mice were fully viable and displayed normal postnatal growth and development of the mitochondrial oxidative phosphorylation system. Nevertheless, they presented with mild deterioration of heart function. Our results demonstrated that Tmem70 knockout in the mouse results in embryonic lethality due to the lack of ATP synthase and impairment of mitochondrial energy provision. This is analogous to TMEM70 dysfunction in humans and verifies the crucial role of this factor in the biosynthesis and assembly of mammalian ATP synthase.

• MeSH
• Adenosine Triphosphate metabolism   MeSH
• Homozygote MeSH
• Cardiomyopathies metabolism   MeSH
• Membrane Proteins deficiency   genetics   metabolism   MeSH
• Mitochondrial Membranes metabolism   MeSH
• Mitochondrial Diseases genetics   metabolism   MeSH
• Mitochondrial Proteins deficiency   genetics   metabolism   MeSH
• Mitochondrial Proton-Translocating ATPases biosynthesis   genetics   metabolism   MeSH
• Mitochondria metabolism   MeSH
• Mutation MeSH
• Mice, Knockout MeSH
• Mice MeSH
• Oxidative Phosphorylation MeSH
• Pregnancy MeSH
• Metabolism, Inborn Errors metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Pregnancy MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

OBJECTIVES: TMEM70 deficiency is the most common nuclear-encoded defect affecting the ATP synthase. In this multicentre retrospective study we characterise the natural history of the disease, treatment and outcome in 48 patients with mutations in TMEM70. Eleven centers from eight European countries, Turkey and Israel participated. RESULTS: All 27 Roma and eight non-Roma patients were homozygous for the common mutation c.317-2A > G. Five patients were compound heterozygotes for the common mutation and mutations c.470 T > A, c.628A > C, c.118_119insGT or c.251delC. Six Arab Muslims and two Turkish patients were homozygous for mutations c.238C > T, c.316 + 1G > T, c.336 T > A, c.578_579delCA, c.535C > T, c.359delC. Age of onset was neonatal in 41 patients, infantile in six cases and two years in one child. The most frequent symptoms at onset were poor feeding, hypotonia, lethargy, respiratory and heart failure, accompanied by lactic acidosis, 3-methylglutaconic aciduria and hyperammonaemia. Symptoms further included: developmental delay (98%), hypotonia (95%), faltering growth (94%), short stature (89%), non-progressive cardiomyopathy (89%), microcephaly (71%), facial dysmorphism (66%), hypospadias (50% of the males), persistent pulmonary hypertension of the newborn (22%) and Wolff-Parkinson-White syndrome (13%). One or more acute metabolic crises occurred in 24 surviving children, frequently followed by developmental regression. Hyperammonaemic episodes responded well to infusion with glucose and lipid emulsion, and ammonia scavengers or haemodiafiltration. Ten-year survival was 63%, importantly for prognostication, no child died after the age of five years. CONCLUSION: TMEM70 deficiency is a panethnic, multisystemic disease with variable outcome depending mainly on adequate management of hyperammonaemic crises in the neonatal period and early childhood.

• MeSH
• Acidosis, Lactic genetics   MeSH
• Child MeSH
• Adult MeSH
• Heterozygote MeSH
• Homozygote MeSH
• Hyperammonemia genetics   MeSH
• Kaplan-Meier Estimate MeSH
• Cardiomyopathies genetics   MeSH
• Infant MeSH
• Muscle, Skeletal pathology   MeSH
• Humans MeSH
• Disease Management MeSH
• Membrane Proteins deficiency   genetics   MeSH
• Mitochondrial Proteins deficiency   genetics   MeSH
• Adolescent MeSH
• Young Adult MeSH
• Mutation MeSH
• Infant, Newborn MeSH
• Child, Preschool MeSH
• Retrospective Studies MeSH
• Metabolism, Inborn Errors genetics   MeSH
• Check Tag
• Child MeSH
• Adult MeSH
• Infant MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Male MeSH
• Infant, Newborn MeSH
• Child, Preschool MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Multicenter Study MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Europe MeSH
• Israel MeSH
• Turkey MeSH