Fibulin-4 is an extracellular matrix protein essential for elastic fiber formation. Frameshift and missense mutations in the fibulin-4 gene (EFEMP2/FBLN4) cause autosomal recessive cutis laxa (ARCL) 1B, characterized by loose skin, aortic aneurysm, arterial tortuosity, lung emphysema, and skeletal abnormalities. Homozygous missense mutations in FBLN4 are a prevalent cause of ARCL 1B. Here we generated a knock-in mouse strain bearing a recurrent fibulin-4 E57K homozygous missense mutation. The mutant mice survived into adulthood and displayed abnormalities in multiple organ systems, including loose skin, bent forelimb, aortic aneurysm, tortuous artery, and pulmonary emphysema. Biochemical studies of dermal fibroblasts showed that fibulin-4 E57K mutant protein was produced but was prone to dimer formation and inefficiently secreted, thereby triggering an endoplasmic reticulum stress response. Immunohistochemistry detected a low level of fibulin-4 E57K protein in the knock-in skin along with altered expression of selected elastic fiber components. Processing of a precursor to mature lysyl oxidase, an enzyme involved in cross-linking of elastin and collagen, was compromised. The knock-in skin had a reduced level of desmosine, an elastin-specific cross-link compound, and ultrastructurally abnormal elastic fibers. Surprisingly, structurally aberrant collagen fibrils and altered organization into fibers were characteristics of the knock-in dermis and forelimb tendons. Type I collagen extracted from the knock-in skin had decreased amounts of covalent intermolecular cross-links, which could contribute to the collagen fibril abnormalities. Our studies provide the first evidence that fibulin-4 plays a role in regulating collagen fibril assembly and offer a preclinical platform for developing treatments for ARCL 1B.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4571872 | PMC |
http://dx.doi.org/10.1074/jbc.M115.640425 | DOI Listing |
Am J Physiol Heart Circ Physiol
July 2023
Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, Missouri, United States.
Thoracic aortic aneurysm is characterized by dilation of the aortic diameter by greater than 50%, which can lead to dissection or rupture. Common histopathology includes extracellular matrix remodeling that may affect transmural mass transport, defined as the movement of fluids and solutes across the wall. We measured in vitro ascending thoracic aorta mass transport in a mouse model with partial aneurysm phenotype penetration due to a mutation in the extracellular matrix protein fibulin-4 [, referred to as MU-A (aneurysm) or MU-NA (no aneurysm)].
View Article and Find Full Text PDFSci Adv
May 2017
Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Homozygous or compound heterozygous mutations in fibulin-4 () lead to autosomal recessive cutis laxa type 1B (ARCL1B), a multisystem disorder characterized by significant cardiovascular abnormalities, including abnormal elastin assembly, arterial tortuosity, and aortic aneurysms. We sought to determine the consequences of a human disease-causing mutation in (E57K) on the cardiovascular system and vascular elastic fibers in a mouse model of ARCL1B. mice were hypertensive and developed arterial elongation, tortuosity, and ascending aortic aneurysms.
View Article and Find Full Text PDFMatrix Biol
December 2016
Department of Experimental Medicine I, Nikolaus-Fiebiger Center of Molecular Medicine, University of Erlangen-Nürnberg, 91054 Erlangen, Germany.
Fibulin-4 is a 60kDa calcium binding glycoprotein that has an important role in development and integrity of extracellular matrices. It interacts with elastin, fibrillin-1 and collagen IV as well as with lysyl oxidases and is involved in elastogenesis and cross-link formation. To date, several mutations in the fibulin-4 gene (FBLN4/EFEMP2) are known in patients whose major symptoms are vascular deformities, aneurysm, cutis laxa, joint laxity, or arachnodactyly.
View Article and Find Full Text PDFJ Biol Chem
August 2015
From the Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107,
Fibulin-4 is an extracellular matrix protein essential for elastic fiber formation. Frameshift and missense mutations in the fibulin-4 gene (EFEMP2/FBLN4) cause autosomal recessive cutis laxa (ARCL) 1B, characterized by loose skin, aortic aneurysm, arterial tortuosity, lung emphysema, and skeletal abnormalities. Homozygous missense mutations in FBLN4 are a prevalent cause of ARCL 1B.
View Article and Find Full Text PDFAm J Hum Genet
June 2006
Department of Pediatrics Washington University School of Medicine, St. Louis, MO 63110, USA.
Cutis laxa is a condition characterized by redundant, pendulous, and inelastic skin. We identified a patient with recessive inheritance of a missense mutation (169G-->A; E57K) in the Fibulin-4 gene. She had multiple bone fractures at birth and was diagnosed with cutis laxa, vascular tortuosity, ascending aortic aneurysm, developmental emphysema, inguinal and diaphragmatic hernia, joint laxity, and pectus excavatum by age 2 years.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!