Mutations In Extracellular Matrix Protein Research Articles

The Extracellular Matrix in Skin Inflammation and Infection.

The extracellular matrix (ECM) is an integral component of all organs and plays a pivotal role in tissue homeostasis and repair. While the ECM was long thought to mostly have passive functions by providing physical stability to tissues, detailed characterization of its physical structure and biochemical properties have uncovered an unprecedented broad spectrum of functions. It is now clear that the ECM not only comprises the essential building block of tissues but also actively supports and maintains the dynamic interplay between tissue compartments as well as embedded resident and recruited inflammatory cells in response to pathologic stimuli. On the other hand, certain pathogens such as bacteria and viruses have evolved strategies that exploit ECM structures for infection of cells and tissues, and mutations in ECM proteins can give rise to a variety of genetic conditions. Here, we review the composition, structure and function of the ECM in cutaneous homeostasis, inflammatory skin diseases such as psoriasis and atopic dermatitis as well as infections as a paradigm for understanding its wider role in human health.

Lipoid proteinosis and epilepsy: Molecular analysis

Aim: Lipoid proteinosis (LP) is also known as Urbach-Wiethe disease which is a rare autosomal recessive disorder characterized by intracellular accumulation of hyaline material in skin and mucosae. LP has typical neurological, dermatological and radiological findings. The pathogenesis of disease is unknown. In literature several cases have been reported up to date. Mutations in extracellular matrix protein 1 (ECM1) gene have been found to cause the disease. We evaluated the molecular features of a family diagnosed with LP and evaluate the known and novel mutations of LP. Material and Methods: Genomic DNA was extracted from peripheral blood of the patients and family members including clinically normal parents and two siblings of the two affected subjects by using a commercial DNA extraction kit. Polymerase chain reaction was performed for all 10 exons of ECM1 gene by using the primers defined. Results: All of the exons of the ECM1 gene were sequenced and this revealed a 2-bp deletion in exon 7 of the ECM1 gene in both patients and both parents. Patients have the homozygous 2-bp deletions (c735del TG) and the parents and two healthy siblings showed heterozygous 2-bp deletion. Conclusions: Our patients found to be homozygous for the deletion in ECM1 gene. In order to understand the molecular pathology of the disease in detail, further functional analysis of the mutations should be performed.

Different Forms of ER Stress in Chondrocytes Result in Short Stature Disorders and Degenerative Cartilage Diseases: New Insights by Cartilage-Specific ERp57 Knockout Mice.

Cartilage is essential for skeletal development by endochondral ossification. The only cell type within the tissue, the chondrocyte, is responsible for the production of macromolecules for the extracellular matrix (ECM). Before proteins and proteoglycans are secreted, they undergo posttranslational modification and folding in the endoplasmic reticulum (ER). However, the ER folding capacity in the chondrocytes has to be balanced with physiological parameters like energy and oxygen levels. Specific cellular conditions, e.g., a high protein demand, or pathologic situations disrupt ER homeostasis and lead to the accumulation of poorly folded or misfolded proteins. This state is called ER stress and induces a cellular quality control system, the unfolded protein response (UPR), to restore homeostasis. Different mouse models with ER stress in chondrocytes display comparable skeletal phenotypes representing chondrodysplasias. Therefore, ER stress itself seems to be involved in the pathogenesis of these diseases. It is remarkable that chondrodysplasias with a comparable phenotype arise independent from the sources of ER stress, which are as follows: (1) mutations in ECM proteins leading to aggregation, (2) deficiencies in ER chaperones, (3) mutations in UPR signaling factors, or (4) deficiencies in the degradation of aggregated proteins. In any case, the resulting UPR substantially impairs ECM protein synthesis, chondrocyte proliferation, and/or differentiation or regulation of autophagy and apoptosis. Notably, chondrodysplasias arise no matter if single or multiple events are affected. We analyzed cartilage-specific ERp57 knockout mice and demonstrated that the deficiency of this single protein disulfide isomerase, which is responsible for formation of disulfide bridges in ECM glycoproteins, is sufficient to induce ER stress and to cause an ER stress-related bone phenotype. These mice therefore qualify as a novel model for the analysis of ER stress in chondrocytes. They give new insights in ER stress-related short stature disorders and enable the analysis of ER stress in other cartilage diseases, such as osteoarthritis.

Enzymatic Dissociation Makes Skeletal Muscle Fibers Susceptible to Osmotic Stress and More Prone to Mitochondrial Calcium Uptake

Introduction: Enzymatic dissociation using collagenases is a frequently used method when studying function in individual adult skeletal muscles fibers. A potential problem with this method is that enzymatic disruption of the extracellular matrix may alter the anchorage of the intracellular cytoskeleton to the cell membrane and hence affect cellular structure and function.Methods: We used single mouse flexor digitorum brevis (FDB) fibers isolated either by enzymatic dissociation with collagenase or by mechanical dissection, which leaves the immediate extracellular matrix intact. The gross structure of isolated fibers was assessed with Second Harmonic Generation (SHG) microscopy. Cytosolic and mitochondrial free [Ca2+] were measured with fluo-3 and rhod-2, respectively.Results: In comparison to dissected fibers, enzymatically dissociated fibers show: (1) less elaborate gross structure; (2) increased susceptibility to develop defective intracellular Ca2+ handling (increased basal cytosolic [Ca2+], spontaneous Ca2+ waves and Ca2+ sparks) in response to a hypo-osmotic shock (3 min exposure to 50% of the normal NaCl concentration); (3) increased mitochondrial Ca2+ uptake during repeated tetanic contractions.Conclusion: Disruption of the extracellular matrix results in marked changes in muscle fiber structure and function. This raises concerns when interpreting results obtained in experiments performed with enzymatically dissociated fibers. Moreover, our results support a role of altered cellular Ca2+ homeostasis in the disease process of muscle dystrophies caused by mutations in extracellular matrix proteins.

Epidermodysplasia Verruciformis in Lipoid Proteinosis: Case Report and Discussion of Pathophysiology

Lipoid proteinosis (LP) is a rare autosomal recessive genodermatosis caused by mutations in extracellular matrix protein 1 (ECM1) that involves deposition of basement membrane-like material in the skin and other organs. Epidermodysplasia verruciformis (EV) is also a rare autosomal recessive genodermatosis involving susceptibility to human papillomavirus (HPV) infections and squamous cell carcinoma, caused in most cases by homozygous mutations in EVER1 or EVER2. We describe a case of EV in a patient with LP and discuss the pathophysiology. A 3-year-old Lebanese girl presented with hoarseness, beaded papules along the eyelid margins, waxy papules and plaques on her head and neck, and lichenoid verrucous papules on the forearms and hands. Histopathology of the waxy papules exhibited deposition of periodic acid Schiff-positive basement membrane-like material in the superficial dermis, characteristic of LP. The verruca plana-like lesions exhibited acanthosis and enlarged keratinocytes with pale blue-grey cytoplasm and a perinuclear halo, consistent with verrucae and EV. Polymerase chain reaction amplification and sequencing of ECM1, EVER1, and EVER2 demonstrated a homozygous point mutation, c.389C>T (p.Thr130Met), in exon 6 of ECM1 and a heterozygous point mutation, c.917 A>T (p.Asn306Ile), in exon 8 in EVER2, known to cause EV in homozygous patients. The homozygous point mutation c.389C>T in ECM1 may be a novel mutation causing LP. Verruca plana-like lesions seen in LP appear to represent a form of acquired EV. In this patient, a heterozygous mutation in EVER2 at c.917 A>T may also have conferred susceptibility to HPV infection.

Extracellular matrix and the mechanics of large artery development

The large, elastic arteries, as their name suggests, provide elastic distention and recoil during the cardiac cycle in vertebrate animals. The arteries are distended from the pressure of ejecting blood during the active contraction of the left ventricle (LV) during systole and recoil to their original dimensions during relaxation of the LV during diastole. The cyclic distension occurs with minimal energy loss, due to the elastic properties of one of the major structural extracellular matrix (ECM) components, elastin. The maximum distension is limited to prevent damage to the artery by another major ECM component, collagen. The mix of ECM components in the wall largely determines the passive mechanical behavior of the arteries and the subsequent load on the heart during systole. While much research has focused on initial artery formation, there has been less attention on the continuing development of the artery to produce the mature composite wall complete with endothelial cells (ECs), smooth muscle cells (SMCs), and the necessary mix of ECM components for proper cardiovascular function. This review focuses on the physiology of large artery development, including SMC differentiation and ECM production. The effects of hemodynamic forces and ECM deposition on the evolving arterial structure and function are discussed. Human diseases and mouse models with genetic mutations in ECM proteins that affect large artery development are summarized. A review of constitutive models and growth and remodeling theories is presented, along with future directions to improve understanding of ECM and the mechanics of large artery development.

Prominent corneal nerves: a novel sign of lipoid proteinosis

AimDetailed longitudinal evaluation of corneal and other ophthalmological features of patients with lipoid proteinosis (LP).MethodsOphthalmological examinations, chart review, ultrasound biomicroscopy, corneal confocal microscopic examinations with Nidek confoScan 4 and direct...

English

  A number of mutations in extracellular matrix protein 1 (ECM1) that is a glycoprotein and expressed in skin and other tissues are reported to cause a rare, autosomal recessive disorder called lipoid proteinosis (LP). The peculiar manifestation of LP is hoarseness of voice caused by laryngeal infiltration in infancy. Skin and mucous membrane changes clinically become apparent, and the disease typically follows a slowly progressive, yet often benign, course. About 300 cases of LP have been reported, but occurrence in siblings is rare. In this study, two siblings (18 and 24-year-old) of a Pakistani family were reported to have LP. This study presents two brothers with scaly itchy lesions on whole body, hoarse voice and macroglossia. Their deceased father had similar clinical manifestations but mother, younger brother and sister were unaffected. Blood from affected and clinically unaffected family members were collected with informed consent. The ECM1 gene containing 10 exons were amplified and sequenced. Both patients showed non-pathogenic missense and silent mutations in exon 6 and 8. In exon 6, a nucleotide C was substituted to T (C®T) at codon 2, in patient 1. This non-pathogenic missense mutation causes appearance of amino acid cysteine instead of arginine that is part of normal ECM1 protein. In patient 2, polymorphism of nucleotide C to T (C/T) was observed observed in exion 6 that may lead to the appearance of cysteine and/or arginine in the resulting gene product. In exon 8, a nucleotide G was substituted to A (G®A) at codon 53, in patient 1. This substitution leads to a silent mutation asserine is coded by both forms of codon. In patient 2, polymorphism of nucleotide G to A (G/A) was observed in exion 8 that do not cause any change in the coded amino acid. These findings represent a set of missense and silent mutations supporting an unusual function of ECM1 protein, broadening the spectrum of disease-linked mutations in rare cases of LP.   Key words: Lipoid proteinosis, extracellular matrix protein 1 (ECM1), missense, silent mutation, single nucleotide polymorphism, exons 6 and 8, genodermatosis.

A Case of Hyalinosis Cuits et Mucosae with Mutations in Extracellular Matrix Protein 1 Gene

A Case of Hyalinosis Cuits et Mucosae with Mutations in Extracellular Matrix Protein 1 Gene

Targeted induction of endoplasmic reticulum stress induces cartilage pathology.

Pathologies caused by mutations in extracellular matrix proteins are generally considered to result from the synthesis of extracellular matrices that are defective. Mutations in type X collagen cause metaphyseal chondrodysplasia type Schmid (MCDS), a disorder characterised by dwarfism and an expanded growth plate hypertrophic zone. We generated a knock-in mouse model of an MCDS–causing mutation (COL10A1 p.Asn617Lys) to investigate pathogenic mechanisms linking genotype and phenotype. Mice expressing the collagen X mutation had shortened limbs and an expanded hypertrophic zone. Chondrocytes in the hypertrophic zone exhibited endoplasmic reticulum (ER) stress and a robust unfolded protein response (UPR) due to intracellular retention of mutant protein. Hypertrophic chondrocyte differentiation and osteoclast recruitment were significantly reduced indicating that the hypertrophic zone was expanded due to a decreased rate of VEGF–mediated vascular invasion of the growth plate. To test directly the role of ER stress and UPR in generating the MCDS phenotype, we produced transgenic mouse lines that used the collagen X promoter to drive expression of an ER stress–inducing protein (the cog mutant of thyroglobulin) in hypertrophic chondrocytes. The hypertrophic chondrocytes in this mouse exhibited ER stress with a characteristic UPR response. In addition, the hypertrophic zone was expanded, gene expression patterns were disrupted, osteoclast recruitment to the vascular invasion front was reduced, and long bone growth decreased. Our data demonstrate that triggering ER stress per se in hypertrophic chondrocytes is sufficient to induce the essential features of the cartilage pathology associated with MCDS and confirm that ER stress is a central pathogenic factor in the disease mechanism. These findings support the contention that ER stress may play a direct role in the pathogenesis of many connective tissue disorders associated with the expression of mutant extracellular matrix proteins.

The molecular basis of lipoid proteinosis: mutations in extracellular matrix protein 1

Lipoid proteinosis (OMIM 247100), also known as Urbach-Wiethe disease or hyalinosis cutis et mucosae, is a rare autosomal recessive disorder characterized by generalized thickening and scarring of the skin and mucosae. In 2002, the disorder was mapped to a locus on chromosome 1q21 and pathogenic mutations were identified in the ECM1 gene, which encodes for the glycoprotein extracellular matrix protein 1 (ECM1). ECM1 has since been shown to have several important biological functions. It has a role in the structural organization of the dermis (binding to perlecan, matrix metalloproteinase-9 and fibulin) as well as being targeted as an autoantigen in the acquired disease lichen sclerosus. ECM1 also shows over-expression in certain malignancies and is abnormally expressed in chronologically aged and photo-aged skin. Thus far, 26 different inherited mutations in ECM1 have been reported in lipoid proteinosis. In this article, we provide an update on the molecular pathology of lipoid proteinosis, including the addition of 15 new mutations in ECM1 to the mutation database, and review the biological functions of the ECM1 protein in health and disease.

What Mouse Mutants Teach Us About Extracellular Matrix Function

For many years the extracellular matrix was viewed as a benign scaffold for arranging cells within connective tissues, but it is now being redefined as a dynamic, mobile, and flexible key player in defining cellular behavior. Gene targeting, transgene expression, and spontaneous mutations of extracellular matrix proteins in mice have greatly accelerated our mechanistic view of the structural and instructive functions of the extracellular matrix in developmental and regenerative processes. This review summarizes the phenotypes of genetic mouse models carrying mutations in extracellular matrix proteins, with specific emphasis on recent advances. The application of reverse genetics has demonstrated the multifunctionality of matrix proteins in a biological context and, in addition, has brought a novel perspective to the understanding of human pathologies.

“Free‐Floating” Desmosomes in Lipoid Proteinosis: An Inherent Defect in Keratinocyte Adhesion?

The classic features of lipoid proteinosis - beadlike papules and hoarseness - result from the accumulation of hyaline material in the mucocutaneous dermis. However, the characteristic manifestation in children - erosive, crusted lesions that lead to scarring - is rarely discussed and poorly understood. Lipoid proteinosis results from mutations in extracellular matrix protein 1, but the function of this protein is largely unknown. We performed ultrastructural studies on lesional epidermis, cultured monolayer keratinocytes, and raft keratinocyte cultures from blistering lesions of a child with lipoid proteinosis. All sections showed the dissociation of relatively intact desmosomes from keratinocytes, with desmosomes that were "free-floating" in the intercellular spaces or attached by thin strands to the cell membrane. These changes were present in serial sections of both tissue and cultured keratinocytes, suggesting this observation to be an inherent feature of keratinocytes devoid of extracellular matrix protein 1, rather than an artifact. Although additional patients should be studied, the diminished appearance of the inner dense plaque - the region of attachment of keratin intermediate filaments to desmosomal proteins - provides preliminary evidence that extracellular matrix protein 1 may participate in attaching keratin intermediate filaments to desmosomal region protein(s).

Autoantibodies to extracellular matrix protein 1 in lichen sclerosus

Lichen sclerosus is a common acquired inflammatory disorder of skin and mucous membranes. The aetiology is unknown, although HLA-subtype susceptibility and high rates of other autoimmune disorders suggest that autoantibodies to specific mucocutaneous antigens are involved. The clinicopathological similarities between lichen sclerosus and lipoid proteinosis, which results from mutations in extracellular matrix protein 1 (ECM1), suggest this protein as an autoantigen. We analysed serum autoantibody profiles in 171 individuals (86 with lichen sclerosus, 85 healthy controls) by immunoblotting of extracts from normal human skin and lipoid proteinosis skin (lacking ECM1). We generated a full-length glutathione-S-transferase fusion protein for ECM1 to confirm specific immunoreactivity. We affinity-purified serum from patients with lichen sclerosus and did indirect immunofluorescence microscopy on normal skin with or without preabsorption with recombinant ECM1. By immunoblotting, IgG autoantibodies were found in 20 (67% [95% CI 45-84]) of 30 lichen sclerosus serum samples. The highest titre was 1 in 20. The bands were not detected in ECM1-deficient substrate. These samples, and those from 56 other patients with lichen sclerosus, showed immunoreactivity to the recombinant ECM1 protein (64 of 86 positive; 74% [65-84]). Only six (7% [2-13]) of 85 control serum samples were positive. Affinity-purified IgG from serum of patients with lichen sclerosus labelled skin similarly to a polyclonal antibody to ECM1. The positive staining was blocked by preabsorption with excess recombinant ECM1 protein. These findings provide evidence for a specific humoral immune response to ECM1 in lichen sclerosus and offer insight into disease diagnosis, monitoring, and approaches to treatment.

Extracellular Matrix Protein 1 Gene (ECM1) Mutations in Lipoid Proteinosis and Genotype-Phenotype Correlation

The autosomal recessive disorder lipoid proteinosis results from mutations in extracellular matrix protein 1 (ECM1), a glycoprotein expressed in several tissues (including skin) and composed of two alternatively spliced isoforms, ECM1a and ECM1b, the latter lacking exon 7 of this 10-exon gene (ECM1). To date, mutations that either affect ECM1a alone or perturb both ECM1 transcripts have been demonstrated in six cases. However, lipoid proteinosis is clinically heterogeneous with affected individuals displaying differing degrees of skin scarring and infiltration, variable signs of hoarseness and respiratory distress, and in some cases neurological abnormalities such as temporal lobe epilepsy. In this study, we sequenced ECM1 in 10 further unrelated patients with lipoid proteinosis to extend genotype-phenotype correlation and to add to the mutation database. We identified seven new homozygous nonsense or frameshift mutations: R53X (exon 3); 243delG (exon 4); 507delT (exon 6); 735delTG (exon 7); 785delA (exon 7); 892delC (exon 7) and 1190insC (exon 8), as well as two new compound heterozygous mutations: W160X/F167I (exon 6) and 542insAA/R243X (exons 6/7), none of which were found in controls. The mutation 507delT occurred in two unrelated subjects on different ECM1 haplotypes and may therefore represent a recurrent mutation in lipoid proteinosis. Taken with the previously documented mutations in ECM1, this study supports the view that exons 6 and 7 are the most common sites for ECM1 mutations in lipoid proteinosis. Clinically, it appears that mutations outside exon 7 are usually associated with a slightly more severe mucocutaneous lipoid proteinosis phenotype, but neurological features do not show any specific genotype-phenotype correlation.