Heritable diseases of collagen

High quality repair of osteochondral defects in rats using the extracellular matrix of antler stem cells

BACKGROUND

Cartilage defects are some of the most common causes of arthritis. Cartilage lesions caused by inflammation, trauma or degenerative disease normally result in osteochondral defects. Previous studies have shown that decellularized extracellular matrix (ECM) derived from autologous, allogenic, or xenogeneic mesenchymal stromal cells (MSCs) can effectively restore osteochondral integrity.

AIM

To determine whether the decellularized ECM of antler reserve mesenchymal cells (RMCs), a xenogeneic material from antler stem cells, is superior to the currently available treatments for osteochondral defects.

METHODS

We isolated the RMCs from a 60-d-old sika deer antler and cultured them in vitro to 70% confluence; 50 mg/mL L-ascorbic acid was then added to the medium to stimulate ECM deposition. Decellularized sheets of adipocyte-derived MSCs (aMSCs) and antlerogenic periosteal cells (another type of antler stem cells) were used as the controls. Three weeks after ascorbic acid stimulation, the ECM sheets were harvested and applied to the osteochondral defects in rat knee joints.

RESULTS

The defects were successfully repaired by applying the ECM-sheets. The highest quality of repair was achieved in the RMC-ECM group both in vitro (including cell attachment and proliferation), and in vivo (including the simultaneous regeneration of well-vascularized subchondral bone and avascular articular hyaline cartilage integrated with surrounding native tissues). Notably, the antler-stem-cell-derived ECM (xenogeneic) performed better than the aMSC-ECM (allogenic), while the ECM of the active antler stem cells was superior to that of the quiescent antler stem cells.

CONCLUSION

Decellularized xenogeneic ECM derived from the antler stem cell, particularly the active form (RMC-ECM), can achieve high quality repair/reconstruction of osteochondral defects, suggesting that selection of decellularized ECM for such repair should be focused more on bioactivity rather than kinship.

Single-Cell Integration of BMD GWAS Results Prioritize Candidate Genes Influencing Age-Related Bone Loss

The regulation of bone mineral density (BMD) is highly influenced by genetics and age. Although genome-wide association studies (GWAS) for BMD have uncovered many genes through their proximity to associated variants (variant nearest-neighbor [VNN] genes), the cell-specific mechanisms of each VNN gene remain unclear. This is primarily due to the inability to prioritize these genes by cell type and age-related expression. Using age-related transcriptomics, we found that the expression of many VNN genes was upregulated in the bone and marrow from aged mice. Candidate genes from GWAS were investigated using single-cell RNA-sequencing (scRNA-seq) datasets to enrich for cell-specific expression signatures. VNN candidate genes are highly enriched in osteo-lineage cells, osteocytes, hypertrophic chondrocytes, and Lepr+ mesenchymal stem cells. These data were used to generate a "blueprint" for Cre-loxp mouse line selection for functional validation of candidate genes and further investigation of their role in BMD maintenance throughout aging. In VNN-gene-enriched cells, Sparc, encoding the extracellular matrix (ECM) protein osteonectin, was robustly expressed. This, along with expression of numerous other ECM genes, indicates that many VNN genes likely have roles in ECM deposition by osteoblasts. Overall, we provide data supporting streamlined translation of GWAS candidate genes to potential novel therapeutic targets for the treatment of osteoporosis. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Dermal ultrasound measurements for bone quality assessment : An investigation of advanced glycation endproducts derived from confocal fluorescence microscopy

Bone quality is increasingly being recognized in the assessment of fracture risk. Nonenzymatic collagen cross-linking with the accumulation of advanced glycation end products stiffens and embrittles collagen fibers thus increasing bone fragility. Echogenicity is an ultrasound (US) parameter that provides information regarding the skin collagen structure. We hypothesized that both skin and bone collagen degrade in parallel fashion. Prospectively collected data of 110 patients undergoing posterior lumbar fusion was analyzed. Preoperative skin US measurements were performed in the lumbar region to assess dermal thickness and echogenicity. Intraoperative bone biopsies from the posterior superior iliac spine were obtained and analyzed with confocal fluorescence microscopy for fluorescent advanced glycation endproducts (fAGEs). Pearson's correlation was calculated to examine relationships between  (1) US and fAGEs, and (2) age and fAGEs stratified by sex. Multivariable linear regression analysis with adjustments for age, sex, body mass index (BMI), diabetes mellitus, and hemoglobin A1c (HbA1c) was used to investigate associations between US and fAGEs. One hundred and ten patients (51.9% female, 61.6 years, BMI 29.8 kg/m2 ) were included in the analysis. In the univariate analysis cortical and trabecular fAGEs decreased with age, but only in women (cortical: r = -0.32, p = 0.031; trabecular: r = -0.32; p = 0.031). After adjusting for age, sex, BMI, diabetes mellitus, and HbA1c, lower dermal (β = 1.01; p = 0.012) and subcutaneous (β = 1.01; p = 0.021) echogenicity increased with increasing cortical fAGEs and lower dermal echogenicity increased with increasing trabecular fAGEs (β = 1.01; p = 0.021). This is the first study demonstrating significant associations between skin US measurements and in vivo bone quality parameters in lumbar fusion patients. As a noninvasive assessment tool, skin US measurements might be incorporated into future practice to investigate bone quality in spine surgery patients.

Preclinical and clinical orthotopic transplantation of decellularized/engineered tracheal scaffolds: A systematic literature review

Severe tracheal injuries that cannot be managed by mobilization and end-to-end anastomosis represent an unmet clinical need and an urgent challenge to face in surgical practice; within this scenario, decellularized scaffolds (eventually bioengineered) are currently a tempting option among tissue engineered substitutes. The success of a decellularized trachea is expression of a balanced approach in cells removal while preserving the extracellular matrix (ECM) architecture/mechanical properties. Revising the literature, many Authors report about different methods for acellular tracheal ECMs development; however, only few of them verified the devices effectiveness by an orthotopic implant in animal models of disease. To support translational medicine in this field, here we provide a systematic review on studies recurring to decellularized/bioengineered tracheas implantation. After describing the specific methodological aspects, orthotopic implant results are verified. Furtherly, the only three clinical cases of compassionate use of tissue engineered tracheas are reported with a focus on outcomes.

Mitral Valve Prolapse and Its Motley Crew-Syndromic Prevalence, Pathophysiology, and Progression of a Common Heart Condition

Mitral valve prolapse (MVP) is a commonly occurring heart condition defined by enlargement and superior displacement of the mitral valve leaflet(s) during systole. Although commonly seen as a standalone disorder, MVP has also been described in case reports and small studies of patients with various genetic syndromes. In this review, we analyzed the prevalence of MVP within syndromes where an association to MVP has previously been reported. We further discussed the shared biological pathways that cause MVP in these syndromes, as well as how MVP in turn causes a diverse array of cardiac and noncardiac complications. We found 105 studies that identified patients with mitral valve anomalies within 18 different genetic, developmental, and connective tissue diseases. We show that some disorders previously believed to have an increased prevalence of MVP, including osteogenesis imperfecta, fragile X syndrome, Down syndrome, and Pseudoxanthoma elasticum, have few to no studies that use up-to-date diagnostic criteria for the disease and therefore may be overestimating the prevalence of MVP within the syndrome. Additionally, we highlight that in contrast to early studies describing MVP as a benign entity, the clinical course experienced by patients can be heterogeneous and may cause significant cardiovascular morbidity and mortality. Currently only surgical correction of MVP is curative, but it is reserved for severe cases in which irreversible complications of MVP may already be established; therefore, a review of clinical guidelines to allow for earlier surgical intervention may be warranted to lower cardiovascular risk in patients with MVP.

Lumenato protects normal human dermal fibroblasts from neutrophil-induced collagen-3 damage in co-cultures

Collagen is the major structural protein in the extracellular matrix of skin produced by fibroblasts. UV exposure results in infiltration of neutrophils within the epidermis and dermis, inducing collagen damage and contributing to the process of photo-aging. Collagen-3 is an integral structural component with collagen-1, and is an important regulator of collagen-1 fibrillogenesis. Addition of neutrophils activated with TNFα to normal human dermal fibroblast cultures, but not their supernatant, caused significant collagen-3 damage. To study whether Lumenato can protect from collagen-3 damage, it was added to co-cultures of Normal human dermal fibroblasts and neutrophils activated with TNFα. Lumenato prevented collagen-3 damage induced by activated neutrophils in a dose-dependent manner in the co-cultures. Lumenato also induced a low rate of collagen-3 synthesis in a dose-dependent manner detected by pro-collagen-3 secretion, but did not affect fibroblast cell number. Although Lumenato inhibited MMP-8, MMP-9, and elastase secreted from neutrophils, its main effect was in inhibiting both NADPH oxidase-producing superoxides and MPO activity-producing halides in a dose-dependent manner that correlated with protection from collagen-3 damage. In conclusion, the results suggest that Lumenato induces low levels of collagen-3 that may contribute for skin health and is very effective in defending the co-cultures from collagen-3 damage by inhibiting free radicals secreted from neutrophils, thus, indicating Lumenato's possible potential for skin protection.

Skin-Nerve Co-Culture Systems for Disease Modeling and Drug Discovery

Prominent clinical problems related to the skin-nerve interface include barrier dysfunction and erythema, but it is the symptoms of pain and itch that most often lead patients to seek medical treatment. Tissue-engineered innervated skin models provide an excellent solution for studying the mechanisms underlying neurocutaneous disorders for drug screening, and cutaneous device development. Innervated skin substitutes provide solutions beyond traditional monolayer cultures and have advantages that make them preferable to in vivo animal studies for certain applications, such as measuring somatosensory transduction. The tissue-engineered innervated skin models replicate the complex stratified epidermis that provides barrier function in native skin, a feature that is lacking in monolayer co-cultures, while allowing for a level of detail in measurement of nerve morphology and function that cannot be achieved in animal models. In this review, the advantages and disadvantages of different cell sources and scaffold materials will be discussed and a presentation of the current state of the field is reviewed. Impact statement A review of the current state of innervated skin substitutes and the considerations that need to be addressed when developing these models. Tissue-engineered skin substitutes are customizable and provide barrier function allowing for screening of topical drugs and for studying nerve function.

Composition, structure and function of the corneal stroma

No other tissue in the body depends more on the composition and organization of the extracellular matrix (ECM) for normal structure and function than the corneal stroma. The precise arrangement and orientation of collagen fibrils, lamellae and keratocytes that occurs during development and is needed in adults to maintain stromal function is dependent on the regulated interaction of multiple ECM components that contribute to attain the unique properties of the cornea: transparency, shape, mechanical strength, and avascularity. This review summarizes the contribution of different ECM components, their structure, regulation and function in modulating the properties of the corneal stroma. Fibril forming collagens (I, III, V), fibril associated collagens with interrupted triple helices (XII and XIV), network forming collagens (IV, VI and VIII) as well as small leucine-rich proteoglycans (SLRP) expressed in the stroma: decorin, biglycan, lumican, keratocan, and fibromodulin are some of the ECM components reviewed in this manuscript. There are spatial and temporal differences in the expression of these ECM components, as well as interactions among them that contribute to stromal function. Unique regions within the stroma like Bowman's layer and Descemet's layer are discussed. To define the complexity of corneal stroma composition and structure as well as the relationship to function is a daunting task. Our knowledge is expanding, and we expect that this review provides a comprehensive overview of current knowledge, definition of gaps and suggests future research directions.

Reproductive options for families at risk of Osteogenesis Imperfecta: a review

Background

Osteogenesis Imperfecta (OI) is a rare genetic disorder involving bone fragility. OI patients typically suffer from numerous fractures, skeletal deformities, shortness of stature and hearing loss. The disorder is characterised by genetic and clinical heterogeneity. Pathogenic variants in more than 20 different genes can lead to OI, and phenotypes can range from mild to lethal forms. As a genetic disorder which undoubtedly affects quality of life, OI significantly alters the reproductive confidence of families at risk. The current review describes a selection of the latest reproductive approaches which may be suitable for prospective parents faced with a risk of OI. The aim of the review is to alleviate suffering in relation to family planning around OI, by enabling prospective parents to make informed and independent decisions.

Main body

The current review provides a comprehensive overview of possible reproductive options for people with OI and for unaffected carriers of OI pathogenic genetic variants. The review considers reproductive options across all phases of family planning, including pre-pregnancy, fertilisation, pregnancy, and post-pregnancy. Special attention is given to the more modern techniques of assisted reproduction, such as preconception carrier screening, preimplantation genetic testing for monogenic diseases and non-invasive prenatal testing. The review outlines the methodologies of the different reproductive approaches available to OI families and highlights their advantages and disadvantages. These are presented as a decision tree, which takes into account the autosomal dominant and autosomal recessive nature of the OI variants, and the OI-related risks of people without OI.

The complex process of decision-making around OI reproductive options is also discussed from an ethical perspective.

Conclusion

The rapid development of molecular techniques has led to the availability of a wide variety of reproductive options for prospective parents faced with a risk of OI. However, such options may raise ethical concerns in terms of methodologies, choice management and good clinical practice in reproductive care, which are yet to be fully addressed.

The Genetics of Thoracic Aortic Aneurysms and Dissection: A Clinical Perspective

Thoracic aortic aneurysm and dissection (TAAD) affects many patients globally and has high mortality rates if undetected. Once thought to be solely a degenerative disease that afflicted the aorta due to high pressure and biomechanical stress, extensive investigation of the heritability and natural history of TAAD has shown a clear genetic basis for the disease. Here, we review both the cellular mechanisms and clinical manifestations of syndromic and non-syndromic TAAD. We particularly focus on genes that have been linked to dissection at diameters <5.0 cm, the current lower bound for surgical intervention. Genetic screening tests to identify patients with TAAD associated mutations that place them at high risk for dissection are also discussed.

Skin Ultrasound Measurement as a Potential Marker of Bone Quality: A Prospective Pilot Study of Patients undergoing Lumbar Spinal Fusion

Bone mineral density (BMD) is not the sole predictor of fracture development. Qualitative markers including bone collagen maturity contribute to bone fragility. Bone and related type I collagen containing connective tissues degenerate in parallel fashion. With aging, changes in skin collagen content and quality have been observed that can be detected on ultrasound (US) as a decrease in dermal thickness and an increase in reticular layer echogenicity. We hypothesized that US dermal thickness and echogenicity correlate with bone collagen maturity. Data of 43 prospectively enrolled patients (mean age 61 years, 24 females), who underwent instrumented, posterior lumbar fusion was analyzed. Besides preoperative quantitative computed tomography (QCT) and skin US measurements, intraoperative bone biopsies were obtained and analyzed with Fourier-transform infrared spectroscopy. Among men, there was no correlation between US measurements and collagen maturity. Among women, dermal layer thickness correlated negatively with collagen maturity in trabecular bone of the iliac crest (r = -0.51, p = 0.01) and vertebra (r = -0.59, p = 0.01) as well as in cortical bone of the iliac crest (r = -0.50, p = 0.02) and vertebra (r = -0.50, p = 0.04). In addition, echogenicity correlated positively with collagen maturity in trabecular vertebral bone (r = 0.59, p = 0.01). In both genders, US measurements showed no correlation with QCT BMD. In summary, ultrasound skin parameters are associated with bone quality factors such as collagen maturity, rather than bone quantity (BMD). Ultrasound of the skin may thereby be an easy and accessible take off point for diagnosis of bone collagen maturity and connective tissue degeneration in the future. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2508-2515, 2019.

Generation of a patient-specific induced pluripotent stem cell line, KSCBi006-A, for osteogenesis imperfecta type I with the COL1A1, c.3162delT mutation

Osteogenesis imperfecta (OI) is a genetic disorder characterized by brittle bones. OI type I is the most common and usually the mildest form. We generated human induced pluripotent stem cells (hiPSCs), KSCBi006-A, from the peripheral blood mononuclear cells of a patient with OI type I using the Sendai virus delivery method. The generated hiPSCs retained the disease-causing DNA mutation (COL1A1, c.3162delT) and showed a normal karyotype. KSCBi006-A also has pluripotency and the capacity for differentiation into the three germ layers. These patient-specific iPSCs provide a valuable cellular modeling platform for OI and a resource for drug screening.

Type III collagen (COL3A1): Gene and protein structure, tissue distribution, and associated diseases

Collagen alpha-1(III) chain, also known as the alpha 1 chain of type III collagen, is a protein that in humans is encoded by the COL3A1 gene. Three alpha 1 chains are required to form the type III collagen molecule which has a long triple-helical domain. Type III collagen, an extracellular matrix protein, is synthesized by cells as a pre-procollagen. It is found as a major structural component in hollow organs such as large blood vessels, uterus and bowel. Other functions of type III collagen include interaction with platelets in the blood clotting cascade and it is also an important signaling molecule in wound healing. Mutations in the COL3A1 gene cause the vascular type of Ehlers-Danlos syndrome (vEDS; OMIM 130050). It is the most serious form of EDS, since patients often die suddenly due to a rupture of large arteries. Inactivation of the murine Col3a1 gene leads to a shorter life span in homozygous mutant mice. The mice die prematurely from a rupture of major arteries mimicking the human vEDS phenotype. The biochemical and cellular effects of COL3A1 mutations have been studied extensively. Most of the glycine mutations lead to the synthesis of type III collagen with reduced thermal stability, which is more susceptible for proteinases. Intracellular accumulation of this normally secreted protein is also found. Ultrastructural analyses have demonstrated dilated rough endoplasmic reticulum and changes in the diameter of collagen fibers. Other clinical conditions associated with type III collagen are several types of fibroses in which increased amounts of type III collagen accumulate in the target organs.

Solubilized eggshell membrane supplies a type III collagen-rich elastic dermal papilla

Signs of aging in facial skin correlate with lifespan and chronic disease; however, the health of aging skin has not been extensively studied. In healthy young skin, the dermis forms a type III collagen-rich dermal papilla, where capillary vessels supply oxygen and nutrients to basal epidermal cells. Chicken eggshell membranes (ESMs) have been used as traditional medicines to promote skin wound healing in Asian countries for many years. Previously, we designed an experimental system in which human dermal fibroblasts (HDFs) were cultured on a dish with a solubilized ESM (S-ESM) bound to an artificial phosphorylcholine polymer; we found that genes that promoted the health of the papillary dermis, such as those encoding type III collagen, were induced in the S-ESM environment. The present study found that a gel with a ratio of 20% type III/80% type I collagen, similar to that of the baby skin, resulted in a higher elasticity than 100% type I collagen (p < 0.05) and that HDFs in the gel showed high mitochondrial activity. Thus, we decided to perform further evaluations to identify the effects of S-ESM on gene expression in the skin of hairless mice and found a significant increase of type III collagen in S-ESM. Picrosirius Red staining showed that type III collagen significantly increased in the papillary dermis after S-ESM treatment. Moreover, S-ESM application significantly improved human arm elasticity and reduced facial wrinkles. ESMs may have applications in extending lifespan by reducing the loss of tissue elasticity through the increase of type III collagen.

Effect of N-(2-aminoethyl) ethanolamine on hypertrophic scarring changes in vitro: Finding novel anti-fibrotic therapies

Hypertrophic scars (HS) limit movement, decrease quality of life, and remain a major impediment to rehabilitation from burns. However, no effective pharmacologic therapies for HS exist. Here we tested the in vitro anti-fibrotic effects of the novel chemical N-(2-aminoethyl) ethanolamine (AEEA) at non-toxic concentrations. Scanning electron microscopy showed that AEEA markedly altered the structure of the extracellular matrix (ECM) produced by primary dermal fibroblasts isolated from a HS of a burn patient (HTS). Compression atomic force microscopy revealed that AEEA stiffened the 3D nanostructure of ECM formed by HTS fibroblasts. Western blot analysis in three separate types of primary human dermal fibroblasts (including HTS) showed that AEEA exposure increased the extractability of type I collagen in a dose- and time-dependent fashion, while not increasing collagen synthesis. A comparison of the electrophoretic behavior of the same set of samples under native and denaturing conditions suggested that AEEA alters the 3D structure of type I collagen. The antagonization effect of AEEA to TGF-β1 on ECM formation was also observed. Furthermore, analyses of the anti-fibrotic effects of analogs of AEEA (with modified pharmacophores) suggest the existence of a chemical structure-activity relationship. Thus, AEEA and its analogs may inhibit HS development; further study and optimization of analogs may be a promising strategy for the discovery for effective HS therapies.

Osteogenesis imperfecta with ectopic mineralizations in dentin and cementum and a COL1A2 mutation

We report a Thai father (patient 1) and his daughter (patient 2) affected with osteogenesis imperfecta type IV and dentinogenesis imperfecta. Both were heterozygous for the c.1451G>A (p.Gly484Glu) mutation in COL1A2. The father, a Thai boxer, had very mild osteogenesis imperfecta with no history of low-trauma bone fractures. Scanning electron micrography of the primary teeth with DI of the patient 2, and the primary teeth with DI of another OI patient with OI showed newly recognized dental manifestations of teeth with DI. Normal dentin and cementum might have small areas of ectopic mineralizations. Teeth affected with DI have well-organized ectopic mineralizations in dentin and cementum. The "French-fries-appearance" of the crystals at the cemento-dentinal junction and abnormal cementum have never been reported to be associated with dentinogenesis imperfecta, either isolated or osteogenesis imperfecta-associated. Our study shows for the first time that abnormal collagen fibers can lead to ectopic mineralization in dentin and cementum and abnormal cementum can be a part of osteogenesis imperfecta.

Osteogenesis imperfecta: new genes reveal novel mechanisms in bone dysplasia

Osteogenesis imperfecta (OI) is a skeletal dysplasia characterized by fragile bones and short stature and known for its clinical and genetic heterogeneity which is now understood as a collagen-related disorder. During the last decade, research has made remarkable progress in identifying new OI-causing genes and beginning to understand the intertwined molecular and biochemical mechanisms of their gene products. Most cases of OI have dominant inheritance. Each new gene for recessive OI, and a recently identified gene for X-linked OI, has shed new light on its (often previously unsuspected) function in bone biology. Here, we summarize the literature that has contributed to our current understanding of the pathogenesis of OI.

Echocardiographic Evidence of Early Diastolic Dysfunction in Asymptomatic Children with Osteogenesis Imperfecta

OBJECTIVES

Structural and functional cardiovascular abnormalities have been reported in adults with osteogenesis imperfecta (OI); however, there is a lack of paediatric literature on this topic. This study aimed to investigate cardiovascular abnormalities in children with OI in comparison to a control group.

METHODS

This case-control study was conducted at the Sultan Qaboos University Hospital in Muscat, Oman, between May 2013 and August 2014. Data from eight patients with OI and 24 healthy controls were compared using conventional and tissue Doppler echocardiography (TDE).

RESULTS

The OI group had significantly lower peak early mitral valve flow velocity (P = 0.027), peak a-wave reversal in the pulmonary vein (P = 0.030) and peak early diastolic velocity of the mitral valve and upper septum (P = 0.001 each). The peak late diastolic velocities of the mitral valve (P = 0.002) and the upper septum (P = 0.037) were significantly higher in the OI group; however, the peak early/late diastolic velocity ratios of the mitral valve (P = 0.002) and upper septum (P = 0.001) were significantly lower. Left ventricular dimensions and aortic and pulmonary artery diameters were larger in the OI group when indexed for body surface area. Both groups had normal systolic cardiac function.

CONCLUSION

Children with OI had normal systolic cardiac function. However, changes in myocardial tissue Doppler velocities were suggestive of early diastolic cardiac dysfunction. They also had increased left ventricular dimensions and greater vessel diameters. These findings indicate the need for early and detailed structural and functional echocardiographic assessment and follow-up of young patients with OI.

Variability and distribution of COL1A2 (type I collagen) polymorphisms in the central-eastern Mediterranean Basin

BACKGROUND

The most abundant of the collagen protein family, type I collagen is encoded by the COL1A2 gene. The COL1A2 restriction fragment length polymorphisms (RFLPs) EcoRI, RsaI and MspI in samples from several different central-eastern Mediterranean populations were analysed and found to be potentially informative anthropogenetic markers.

AIM

The objective was to define the genetic variability of COL1A2 in the central-eastern Mediterranean and to shed light on its genetic distribution in human groups over a wide geographic area.

SUBJECTS AND METHODS

PCR-RFLP analysis of EcoRI, RsaI and MspI polymorphisms of the COL1A2 gene was performed on oral swab and blood samples from 308 individuals from the central-eastern Mediterranean Basin. The genetic similarities among these groups and other populations described in the literature were investigated through correspondence analysis.

RESULTS

Single-marker data and haplotype frequencies seemed to suggest a genetic homogeneity within the European populations, whereas a certain degree of differentiation was noted for the Egyptians and the Turks.

CONCLUSIONS

The genetic variability in the central-eastern Mediterranean area is probably a result of the geographical barrier of the Mediterranean Sea, which separated European and African populations over time.

The type of variants at the COL3A1 gene associates with the phenotype and severity of vascular Ehlers-Danlos syndrome

Vascular Ehlers-Danlos syndrome (vEDS) is a rare and severe autosomal dominant disorder caused by variants at the COL3A1 gene. Clinical characteristics and course of disease of 215 molecularly proven patients (146 index cases and 69 relatives) were analysed. We found 126 distincts variants that were divided into five groups: (1) Glycine substitutions (n=71), (2) splice-site and in-frame insertions-deletions (n=36), (3) variants leading to haplo-insufficiency (n=7), (4) non-glycine missense variants within the triple helix (n=4 variants), and (5) non-glycine missense variants or in-frame insertions-deletions, in the N- or C-terminal part of the protein (n=8). Overall, our cohort confirmed the severity of the disease with a median age at first complication of 29 years (IQR 22-39), the most frequent being arterial (48%) and digestive (24%) ruptures. Groups 2 and 1 were significantly more severe than groups 3-5, with extreme median ages at first major complication of 23-47 years. Patients of groups 3-5 had a less typical phenotype and remarkably absence of digestive events. The distribution of glycine-replacing amino acids was strongly biased towards more destabilizing residues of the collagen assembly. Thus the natural course of vEDS and the clinical phenotype of patients are influenced by the type of COL3A1 variant. This study also confirms that patients with variants located in the C- and N-termini or leading to haplo-insufficiency have milder course of the disease and less prevalent diagnostic criteria. These findings may help refine diagnostic strategy, genetic counselling and clinical care.

Molecular and Genetic Analyses of Collagen Type IV Mutant Mouse Models of Spontaneous Intracerebral Hemorrhage Identify Mechanisms for Stroke Prevention

BACKGROUND

Collagen type IV alpha1 (COL4A1) and alpha2 (COL4A2) form heterotrimers critical for vascular basement membrane stability and function. Patients with COL4A1 or COL4A2 mutations suffer from diverse cerebrovascular diseases, including cerebral microbleeds, porencephaly, and fatal intracerebral hemorrhage (ICH). However, the pathogenic mechanisms remain unknown, and there is a lack of effective treatment.

METHODS AND RESULTS

Using Col4a1 and Col4a2 mutant mouse models, we investigated the genetic complexity and cellular mechanisms underlying the disease. We found that Col4a1 mutations cause abnormal vascular development, which triggers small-vessel disease, recurrent hemorrhagic strokes, and age-related macroangiopathy. We showed that allelic heterogeneity, genetic context, and environmental factors such as intense exercise or anticoagulant medication modulated disease severity and contributed to phenotypic heterogeneity. We found that intracellular accumulation of mutant collagen in vascular endothelial cells and pericytes was a key triggering factor of ICH. Finally, we showed that treatment of mutant mice with a US Food and Drug Administration-approved chemical chaperone resulted in a decreased collagen intracellular accumulation and a significant reduction in ICH severity.

CONCLUSIONS

Our data are the first to show therapeutic prevention in vivo of ICH resulting from Col4a1 mutation and imply that a mechanism-based therapy promoting protein folding might also prevent ICH in patients with COL4A1 and COL4A2 mutations.

Fourier transform Infrared spectroscopic characterization of mineralizing type I collagen enzymatic trivalent cross-links

The most abundant protein of bone's organic matrix is collagen. One of its most important properties is its cross-linking pattern, which is responsible for the fibrillar matrices' mechanical properties such as tensile strength and viscoelasticity. We have previously described a spectroscopic method based on the resolution of the Amide I and II Fourier transform Infrared (FTIR) bands to their underlying constituent peaks, which allows the determination of divalent and pyridinoline (PYD) collagen cross-links in mineralized thin bone tissue sections with a spatial resolution of ~6.3 μm. In the present study, we used FTIR analysis of a series of biochemically characterized collagen peptides, as well as skin, dentin, and predentin, to examine the potential reasons underlying discrepancies between two different analytical methodologies specifically related to spectral processing. The results identified a novel distinct FTIR underlying peak at ~1,680 cm(-1), correlated with deoxypyridinoline (DPD) content. Furthermore, the two different methods of spectral resolution result in widely different results, while only the method employing well-established spectroscopic routines for spectral resolution provided biologically relevant results, confirming our earlier studies relating the area of the underlying 1,660 cm(-1) with PYD content. The results of the present study describe a new peak that may be used to determine DPD content, confirm our earlier report relating spectroscopic parameters to PYD content, and highlight the importance of the selected spectral resolution methodology.

[Osteogenesis imperfecta]

BACKGROUND

Osteogenesis imperfecta (OI) is the most common genetic disease of bone and is characterized by fragile bones and growth disorders of varying severity. Most cases of OI are inherited autosomal dominant and caused by a mutation in the collagen type I gene.

DIAGNOSTICS

Indications for OI are bone fragility, stunted growth, scoliosis, skull deformities, blue sclera, loss of hearing, dentinogenesis imperfecta and increased laxity of ligaments and skin. In most cases it is possible to make a clinical diagnosis but a skin biopsy or genetic testing can be useful; however, negative results for these tests do not exclude OI.

THERAPY

Therapy must be carried out in a multidisciplinary team and includes conservative (e.g. physiotherapy, rehabilitation programs and orthopedic aids), operative (e.g. intramedullary stabilization procedures) and pharmaceutical (e.g. biphosphonates and growth hormones) procedures.

PROGNOSIS

The prognosis depends on the type of OI and ranges from normal life expectations for type 1 patients up to up to perinatal mortality for type II patients.

Absence of feedback regulation in the synthesis of COL1A1

AIM

Recent studies have emphasized the importance of the extracellular microenvironment in modulating cell growth, motility, and signalling. In this study we have evaluated the ability of a fibroblast derived-extracellular matrix (fd-ECM) to regulate type I collagen synthesis and degradation in fibroblasts.

MAIN METHODS

Fibroblasts were plated on plastic (control) or on fd-ECM and type I collagen synthesis and degradation was evaluated. MTT, western blotting, real time PCR, zymographic analysis and inhibitor assays were utilised to investigate the molecular mechanism of type I collagen regulation by the fd-ECM.

KEY FINDINGS

Fibroblasts plated on fd-ECM showed significant downregulation in the production of type I collagen and COL1A2 messenger ribonucleic acid (mRNA) whilst COL1A1 mRNA remained unchanged. Cells grown on fd-ECM exhibited increased matrix metalloproteases (MMPs) and their corresponding mRNAs. The use of transforming growth factor β (TGF-β) and MMP inhibitors showed that the excess COL1A1 polypeptide chains were degraded by the combined action of MMP-1, MMP-2, MMP-9 and cathepsins.

SIGNIFICANCE

These results show the crucial role played by proteases in regulating extracellular matrix protein levels in the feedback regulation of connective tissue gene expression.

Enhanced in vitro osteoblast differentiation on TiO2 scaffold coated with alginate hydrogel containing simvastatin

The aim of this study was to develop a three-dimensional porous bone graft material as vehicle for simvastatin delivery and to investigate its effect on primary human osteoblasts from three donors. Highly porous titanium dioxide (TiO₂) scaffolds were submerged into simvastatin containing alginate solution. Microstructure of scaffolds, visualized by scanning electron microscopy and micro-computed tomography, revealed an evenly distributed alginate layer covering the surface of TiO₂ scaffold struts. Progressive and sustained simvastatin release was observed for up to 19 days. No cytotoxic effects on osteoblasts were observed by scaffolds with simvastatin when compared to scaffolds without simvastatin. Expression of osteoblast markers (collagen type I alpha 1, alkaline phosphatase, bone morphogenetic protein 2, osteoprotegerin, vascular endothelial growth factor A and osteocalcin) was quantified using real-time reverse transcriptase–polymerase chain reaction. Secretion of osteoprotegerin, vascular endothelial growth factor A and osteocalcin was analysed by multiplex immunoassay (Luminex). The relative expression and secretion of osteocalcin was significantly increased by cells cultured on scaffolds with 10 µM simvastatin when compared to scaffolds without simvastatin after 21 days. In addition, secretion of vascular endothelial growth factor A was significantly enhanced from cells cultured on scaffolds with both 10 nM and 10 µM simvastatin when compared to scaffolds without simvastatin at day 21. In conclusion, the results indicate that simvastatin-coated TiO₂ scaffolds can support a sustained release of simvastatin and induce osteoblast differentiation. The combination of the physical properties of TiO₂ scaffolds with the osteogenic effect of simvastatin may represent a new strategy for bone regeneration in defects where immediate load is wanted or unavailable.

Procollagen lysyl hydroxylase 2 is essential for hypoxia-induced breast cancer metastasis

Metastasis is the leading cause of death among patients who have breast cancer. Understanding the role of the extracellular matrix (ECM) in the metastatic process may lead to the development of improved therapies to treat patients with cancer. Intratumoral hypoxia, found in the majority of breast cancers, is associated with an increased risk of metastasis and mortality. We found that in hypoxic breast cancer cells, hypoxia-inducible factor 1 (HIF-1) activates transcription of the PLOD1 and PLOD2 genes encoding procollagen lysyl hydroxylases that are required for the biogenesis of collagen, which is a major constituent of the ECM. High PLOD2 expression in breast cancer biopsies is associated with increased risk of mortality. We show that PLOD2 is critical for fibrillar collagen formation by breast cancer cells, increases tumor stiffness, and is required for metastasis to lymph nodes and lungs.

Full-mouth rehabilitation for a patient with dentinogenesis imperfecta: a clinical report

Dentinogenesis imperfecta (DI) is a genetic disorder affecting the structural integrity of the dentin that can result in weakened dentin. The affected teeth, especially posterior teeth, often need to be extracted due to severe wear or fracture. This frequently yields a loss of posterior occlusion and occlusal vertical dimension. Besides wear and fracture, anterior teeth often have an unesthetic appearance because of discoloration. Current treatments of choice, including composite bonding restorations and, more recently, all-ceramic restorations, are typically suggested to preserve the remaining teeth and tooth structure. However, there are a limited number of studies on dental implants in patients with DI. The effectiveness of dentin bonding and dental implants in patients with DI is not known. This clinical report describes a 32-year-old Asian woman with DI who underwent full-mouth rehabilitation. The posterior occlusion, mostly in the molar areas, was restored with dental implants and ceramometal restorations. The anterior teeth and premolars were restored with bonded lithium disilicate glass-ceramic pressed veneers and crowns made with computer-aided design/computer-aided manufacturing. This case demonstrates that restoring functional occlusion and esthetics for a patient with DI can be completed successfully using contemporary implant therapy and adhesive dentistry.

GPR56 and the developing cerebral cortex: cells, matrix, and neuronal migration

GPR56, a member of the adhesion G protein-coupled receptor (GPCR) family, is integral to the development of the cortex, as mutations in GPR56 cause bilateral frontoparietal polymicrogyria (BFPP). BFPP is a cobblestone-like cortical malformation, characterized by overmigrating neurons and the formation of neuronal ectopias on the surface of the brain. Since its original cloning a decade ago, GPR56 has emerged from an orphaned and uncharacterized protein to an increasingly well-understood receptor, both in terms of its signaling and function. Collagen III is the ligand of GPR56 in the developing brain. Upon binding to collagen III, GPR56 activates RhoA via coupling to Gα(12/13). This pathway appears to be particularly critical in the preplate neurons, which are the earliest born neurons in the cortex, as the expression pattern of GPR56 in these neurons mimics the anterior to posterior gradient of malformation associated with loss of GPR56 in both humans and mice. Further characterizing the role of GPR56 in the preplate will shed light on the mechanism of cortical development and patterning.

Vitamin C treatment promotes mesenchymal stem cell sheet formation and tissue regeneration by elevating telomerase activity

Cell sheet engineering has been developed as an alternative approach to improve mesenchymal stem cell-mediated tissue regeneration. In this study, we found that vitamin C (Vc) was capable of inducing telomerase activity in periodontal ligament stem cells (PDLSCs), leading to the up-regulated expression of extracellular matrix type I collagen, fibronectin, and integrin β1, stem cell markers Oct4, Sox2, and Nanog as well as osteogenic markers RUNX2, ALP, OCN. Under Vc treatment, PDLSCs can form cell sheet structures because of increased cell matrix production. Interestingly, PDLSC sheets demonstrated a significant improvement in tissue regeneration compared with untreated control dissociated PDLSCs and offered an effective treatment for periodontal defects in a swine model. In addition, bone marrow mesenchymal stem cell sheets and umbilical cord mesenchymal stem cell sheets were also well constructed using this method. The development of Vc-mediated mesenchymal stem cell sheets may provide an easy and practical approach for cell-based tissue regeneration.

Loss of Col3a1, the gene for Ehlers-Danlos syndrome type IV, results in neocortical dyslamination

It has recently been discovered that Collagen III, the encoded protein of the type IV Ehlers-Danlos Syndrome (EDS) gene, is one of the major constituents of the pial basement membrane (BM) and serves as the ligand for GPR56. Mutations in GPR56 cause a severe human brain malformation called bilateral frontoparietal polymicrogyria, in which neurons transmigrate through the BM causing severe mental retardation and frequent seizures. To further characterize the brain phenotype of Col3a1 knockout mice, we performed a detailed histological analysis. We observed a cobblestone-like cortical malformation, with BM breakdown and marginal zone heterotopias in Col3a1⁻/⁻ mouse brains. Surprisingly, the pial BM appeared intact at early stages of development but starting as early as embryonic day (E) 11.5, prominent BM defects were observed and accompanied by neuronal overmigration. Although collagen III is expressed in meningeal fibroblasts (MFs), Col3a1⁻/⁻ MFs present no obvious defects. Furthermore, the expression and posttranslational modification of α-dystroglycan was undisturbed in Col3a1⁻/⁻ mice. Based on the previous finding that mutations in COL3A1 cause type IV EDS, our study indicates a possible common pathological pathway linking connective tissue diseases and brain malformations.

Isolation and culture of human osteoblasts

The skeleton is a dynamic organ that is constantly active throughout life. The highly coordinated actions of bone cells early in life determine the body's shape and form, whilst the constant remodelling (bone resorption followed by an equal amount of bone formation) during adulthood helps to maintain skeletal mass and repair microdamage. When the balance of bone resorption and bone formation becomes unequal, bone diseases, such as osteoporosis, occur. In order to develop drugs to combat bone disease, it is important to know the regulatory systems involved in normal bone formation and resorption. In this chapter, we concentrate on bone formation, providing a detailed guide to isolating and culturing primary human osteoblasts in bone explant cultures, as well as the methodology used to characterise and monitor the function of osteoblasts. In combination, these methods provide a powerful tool in bone cell biology and in the development of new novel treatments for bone disease.

Lathyrism-induced alterations in collagen cross-links influence the mechanical properties of bone material without affecting the mineral

In the present study a rat animal model of lathyrism was employed to decipher whether anatomically confined alterations in collagen cross-links are sufficient to influence the mechanical properties of whole bone. Animal experiments were performed under an ethics committee approved protocol. Sixty-four female (47 day old) rats of equivalent weights were divided into four groups (16 per group): Controls were fed a semi-synthetic diet containing 0.6% calcium and 0.6% phosphorus for 2 or 4 weeks and β-APN treated animals were fed additionally with β-aminopropionitrile (0.1% dry weight). At the end of this period the rats in the four groups were sacrificed, and L2-L6 vertebra were collected. Collagen cross-links were determined by both biochemical and spectroscopic (Fourier transform infrared imaging (FTIRI)) analyses. Mineral content and distribution (BMDD) were determined by quantitative backscattered electron imaging (qBEI), and mineral maturity/crystallinity by FTIRI techniques. Micro-CT was used to describe the architectural properties. Mechanical performance of whole bone as well as of bone matrix material was tested by vertebral compression tests and by nano-indentation, respectively. The data of the present study indicate that β-APN treatment changed whole vertebra properties compared to non-treated rats, including collagen cross-links pattern, trabecular bone volume to tissue ratio and trabecular thickness, which were all decreased (p<0.05). Further, compression tests revealed a significant negative impact of β-APN treatment on maximal force to failure and energy to failure, while stiffness was not influenced. Bone mineral density distribution (BMDD) was not altered either. At the material level, β-APN treated rats exhibited increased Pyd/Divalent cross-link ratios in areas confined to a newly formed bone. Moreover, nano-indentation experiments showed that the E-modulus and hardness were reduced only in newly formed bone areas under the influence of β-APN, despite a similar mineral content. In conclusion the results emphasize the pivotal role of collagen cross-links in the determination of bone quality and mechanical integrity. However, in this rat animal model of lathyrism, the coupled alterations of tissue structural properties make it difficult to weigh the contribution of the anatomically confined material changes to the overall mechanical performance of whole bone. Interestingly, the collagen cross-link ratio in bone forming areas had the same profile as seen in actively bone forming trabecular surfaces in human iliac crest biopsies of osteoporotic patients.

Physiological type I collagen organization induces the formation of a novel class of linear invadosomes

This study shows that fibrillar collagen I is the physiological inducer of a novel class of invadosomes, which we named “linear invadosomes.” They are dependent on the scaffold protein Tks5 and are able to degrade extracellular matrix elements. Moreover, we demonstrate that they are β1- and β3-integrin independent, unlike classical invadosomes.

Invadosomes are F-actin structures capable of degrading the matrix through the activation of matrix metalloproteases. As fibrillar type I collagen promotes pro-matrix metalloproteinase 2 activation by membrane type 1 matrix metalloproteinase, we aimed at investigating the functional relationships between collagen I organization and invadosome induction. We found that fibrillar collagen I induced linear F-actin structures, distributed along the fibrils, on endothelial cells, macrophages, fibroblasts, and tumor cells. These structures share features with conventional invadosomes, as they express cortactin and N-WASP and accumulate the scaffold protein Tks5, which proved essential for their formation. On the basis of their ability to degrade extracellular matrix elements and their original architecture, we named these structures “linear invadosomes.” Interestingly, podosomes or invadopodia were replaced by linear invadosomes upon contact of the cells with fibrillar collagen I. However, linear invadosomes clearly differ from classical invadosomes, as they do not contain paxillin, vinculin, and β1/β3 integrins. Using knockout mouse embryonic fibroblasts and RGD peptide, we demonstrate that linear invadosome formation and activity are independent of β1 and β3 integrins. Finally, linear invadosomes also formed in a three-dimensional collagen matrix. This study demonstrates that fibrillar collagen I is the physiological inducer of a novel class of invadosomes.

G protein-coupled receptor 56 and collagen III, a receptor-ligand pair, regulates cortical development and lamination

GPR56, an orphan G protein-coupled receptor (GPCR) from the family of adhesion GPCRs, plays an indispensable role in cortical development and lamination. Mutations in the GPR56 gene cause a malformed cerebral cortex in both humans and mice that resembles cobblestone lissencephaly, which is characterized by overmigration of neurons beyond the pial basement membrane. However, the molecular mechanisms through which GPR56 regulates cortical development remain elusive due to the unknown status of its ligand. Here we identify collagen, type III, alpha-1 (gene symbol Col3a1) as the ligand of GPR56 through an in vitro biotinylation/proteomics approach. Further studies demonstrated that Col3a1 null mutant mice exhibit overmigration of neurons beyond the pial basement membrane and a cobblestone-like cortical malformation similar to the phenotype seen in Gpr56 null mutant mice. Functional studies suggest that the interaction of collagen III with its receptor GPR56 inhibits neural migration in vitro. As for intracellular signaling, GPR56 couples to the Gα(12/13) family of G proteins and activates RhoA pathway upon ligand binding. Thus, collagen III regulates the proper lamination of the cerebral cortex by acting as the major ligand of GPR56 in the developing brain.

Hydrolyzed eggshell membrane immobilized on phosphorylcholine polymer supplies extracellular matrix environment for human dermal fibroblasts

We have found that a water-soluble alkaline-digested form of eggshell membrane (ASESM) can provide an extracellular matrix (ECM) environment for human dermal fibroblast cells (HDF) in vitro. Avian eggshell membrane (ESM) has a fibrous-meshwork structure and has long been utilized as a Chinese medicine for recovery from burn injuries and wounds in Asian countries. Therefore, ESM is expected to provide an excellent natural material for biomedical use. However, such applications have been hampered by the insolubility of ESM proteins. We have used a recently developed artificial cell membrane biointerface, 2-methacryloyloxyethyl phosphorylcholine polymer (PMBN) to immobilize ASESM proteins. The surface shows a fibrous structure under the atomic force microscope, and adhesion of HDF to ASESM is ASESM-dose-dependent. Quantitative mRNA analysis has revealed that the expression of type III collagen, matrix metalloproteinase-2, and decorin mRNAs is more than two-fold higher when HDF come into contact with a lower dose ASESM proteins immobilized on PMBN surface. A particle-exclusion assay with fixed erythrocytes has visualized secreted water-binding molecules around the cells. Thus, HDF seems to possess an ECM environment on the newly designed PMBN-ASESM surface, and future applications of the ASESM-PMBN system for biomedical use should be of great interest.

Prognostic significance of bone markers in patients with lung cancer metastatic to the skeleton: a review of published data

The presence of bone metastases significantly affects clinical outcome and quality of life parameters in patients with lung cancer. In this review, we aimed to evaluate the predictive value of markers of bone turnover in skeletal morbidity and clinical parameters, including disease-free survival (DFS) and overall survival (OS), in patients with lung cancer metastatic to the skeleton who were receiving bisphosphonate treatment. A comprehensive overview of all articles published from 1995 to date in 3 medical databases (PubMed, Scopus, and Cochrane) was performed using the keywords bone markers and lung cancer. Most bone formation markers (including bone alkaline phosphatase [bALP], osteocalcin [OC], and osteoprotegerin [OPG]), most bone absorption markers (including urinary calcium, osteopontin [OPN], receptor activator of nuclear factor κ-B ligand [RANKL], tartrate-resistant acid phosphatase isoform-5b [TRACP 5b]), and the metabolites of type I collagen had elevated concentrations in patients with lung cancer and bone metastases compared with patients without skeletal involvement. Two large studies showed that urinary N-terminal telopeptide (NTX) levels are a valid diagnostic method for early detection of bone metastases and a more consistent prognosticator than bALP. Treatment with zoledronic acid reduces NTX, TRACP-5b, RANKL, and OPG levels. Furthermore posttherapeutic reduction of urinary NTX levels seems to correlate with lower risk of skeletal-related events (SREs). Levels of markers of bone remodeling reflect the presence of bone metastases and may contribute to early detection of occult skeletal disease or monitor the effect of bisphosphonate treatment. However their ability to predict SREs, as well as DFS and OS, remains debatable.

Decrease in outpatient department visits and operative interventions due to bisphosphonates in children with osteogenesis imperfecta

INTRODUCTION

Bisphosphonates are currently the medical treatment most often used in children with osteogenesis imperfecta (OI). The purpose of this retrospective pre-post study was to evaluate the efficacy of treatment with bisphosphonates. We measured the effect by evaluating the number of outpatient department consultations and operative interventions before and after treatment with bisphosphonates in children with OI.

METHODS AND MATERIALS

Outpatient department consultation and operative intervention frequencies before and after treatment with bisphosphonates were registered. Children who had at least 2 years of medical records before treatment and at least 2 years after treatment were used in this study.

RESULTS

Of 118 children who were treated with bisphosphonates, 51 (23 boys and 28 girls) fulfilled the inclusion criteria. Statistical analysis revealed a significant decrease in outpatient department consultations (P < 0.000) and operative intervention (P < 0.003) before and after bisphosphonate treatment.

CONCLUSION

The pre-post design of our study shows a significant reduction of the number of outpatient department consultations and operative interventions in patients with OI after treatment with bisphosphonates.

α-MSH inhibits TNF-α-induced maturation of human dendritic cells in vitro through the up-regulation of ANXA1

α-Melanocyte-stimulating hormone (α-MSH), an anti-inflammatory and immunomodulatory neuropeptide, has been shown to be effective in the experimental treatment of autoimmune diseases and allograft rejection. However, its regulatory mechanism is still unclear. Mature dendritic cells (DCs) are pivotal initiators of immune response and inflammation. We hypothesized that the regulatory role of α-MSH in DC maturation would contribute to the effects of α-MSH in immune-response-mediated disease models. It was found that α-MSH inhibited tumor necrosis factor-alpha (TNF-α)-induced maturation of human peripheral-monocyte-derived DCs (MoDCs), both phenotypically and functionally. This occurred through the down-regulation of the expression of co-stimulatory molecules CD83 and CD86, the production of IL-12, the promotion of IL-10 secretion, and the MoDC phagocytic activity, suggesting that the inhibition of DC maturation by α-MSH could contribute to the anti-inflammatory effect of this neuropeptide. Furthermore, increased expression of annexin A1 (ANXA1) was found to be responsible for the α-MSH inhibiting effect on TNF-α-induced MoDC maturation, which could be abolished by the treatment of MoDCs with specific, small interfering RNAs targeting ANXA1 (ANXA1-siRNA), suggesting that α-MSH-induced ANXA1 mediates the inhibition. Therefore, α-MSH inhibits TNF-α-induced maturation of human DCs through α-MSH-up-regulated ANXA1, suggesting that inhibition of the maturation of DCs by α-MSH could mediate the anti-inflammatory effect of the neuropeptide. Furthermore, ANXA1 could be identified as a new therapeutic drug target based on the role of DCs in immune-mediated inflammatory diseases.

Haploinsufficiency of the murine Col3a1 locus causes aortic dissection: a novel model of the vascular type of Ehlers-Danlos syndrome

Aims

The vascular type of Ehlers–Danlos syndrome (EDS IV) is an autosomal-dominant disorder characterized by thin translucent skin and extensive bruising. Patients with EDS IV have reduced life expectancy (median 45–50 years) due to spontaneous rupture of arteries (particularly large arteries) or bowel. EDS IV results from mutation of the COL3A1 gene, which encodes the pro-α₁ chains of type III collagen that is secreted into the extracellular matrix, e.g. by smooth muscle cells. A mouse model of EDS IV produced by targeted ablation of Col3a1 has been of limited use as only 10% of homozygous animals survive to adulthood, whereas heterozygous animals do not die from arterial rupture. We report a novel, exploitable model of EDS IV in a spontaneously generated mouse line.

Methods and results

Mice were identified by predisposition to sudden, unexpected death from dissection of the thoracic aorta. Aortic dissection inheritance was autosomal-dominant, presented at an early age (median, 6 weeks) with incomplete penetrance, and had a similar sex ratio bias as EDS IV (2:1, male:female). Molecular genetic analysis demonstrated that the causal mutation is a spontaneous 185 kb deletion, including the promoter region and exons 1–39, of the Col3a1 gene. As in EDS IV, aortic dissection was not associated with elevated blood pressure, aneurysm formation, or infection, but may result from aberrant collagen fibrillogenesis within the aortic wall.

Conclusion

This novel, exploitable mouse line that faithfully models the vascular aspects of human EDS IV provides an important new tool for advancing understanding of EDS IV and of aortic dissection in general.