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Development (Cambridge, England) Mar 2006Pierson syndrome is a recently defined disease usually lethal within the first postnatal months and caused by mutations in the gene encoding laminin beta2 (LAMB2). The...
Pierson syndrome is a recently defined disease usually lethal within the first postnatal months and caused by mutations in the gene encoding laminin beta2 (LAMB2). The hallmarks of Pierson syndrome are congenital nephrotic syndrome accompanied by ocular abnormalities, including microcoria (small pupils), with muscular and neurological developmental defects also present. Lamb2(-/-) mice are a model for Pierson syndrome; they exhibit defects in the kidney glomerular barrier, in the development and organization of the neuromuscular junction, and in the retina. Lamb2(-/-) mice fail to thrive and die very small at 3 weeks of age, but to what extent the kidney and neuromuscular defects each contribute to this severe phenotype has been obscure, though highly relevant to understanding Pierson syndrome. To investigate this, we generated transgenic mouse lines expressing rat laminin beta2 either in muscle or in glomerular epithelial cells (podocytes) and crossed them onto the Lamb2(-/-) background. Rat beta2 was confined in skeletal muscle to synapses and myotendinous junctions, and in kidney to the glomerular basement membrane. In transgenic Lamb2(-/-) mice, beta2 deposition in only glomeruli prevented proteinuria but did not ameliorate the severe phenotype. By contrast, beta2 expression in only muscle restored synaptic architecture and led to greatly improved health, but the mice died from kidney disease at 1 month. Rescue of both glomeruli and synapses was associated with normal weight gain, fertility and lifespan. We conclude that muscle defects in Lamb2(-/-) mice are responsible for the severe failure to thrive phenotype, and that renal replacement therapy alone will be an inadequate treatment for Pierson syndrome.
Topics: Animals; Glomerular Basement Membrane; Kidney Diseases; Laminin; Mice; Mice, Knockout; Mice, Transgenic; Muscle, Skeletal; Muscular Diseases; Mutation; Neuromuscular Junction; Podocytes; Rats; Synapses; Syndrome
PubMed: 16452099
DOI: 10.1242/dev.02270 -
Frontiers in Genetics 2021The laminins (LM) are a family of basement membranes glycoproteins with essential structural roles in supporting epithelia, endothelia, nerves and muscle adhesion, and... (Review)
Review
The laminins (LM) are a family of basement membranes glycoproteins with essential structural roles in supporting epithelia, endothelia, nerves and muscle adhesion, and signaling roles in regulating cell migration, proliferation, stem cell maintenance and differentiation. Laminins are obligate heterotrimers comprised of α, β and γ chains that assemble intracellularly. However, extracellularly these heterotrimers then assemble into higher-order networks interaction between their laminin N-terminal (LN) domains. protein studies have identified assembly kinetics and the structural motifs involved in binding of adjacent LN domains. The physiological importance of these interactions has been identified through the study of pathogenic point mutations in LN domains that lead to syndromic disorders presenting with phenotypes dependent on which laminin gene is mutated. Genotype-phenotype comparison between knockout and LN domain missense mutations of the same laminin allows inferences to be drawn about the roles of laminin network assembly in terms of tissue function. In this review, we will discuss these comparisons in terms of laminin disorders, and the therapeutic options that understanding these processes have allowed. We will also discuss recent findings of non-laminin mediators of laminin network assembly and their implications in terms of basement membrane structure and function.
PubMed: 34456976
DOI: 10.3389/fgene.2021.707087 -
Kidney International Reports Dec 2020
PubMed: 33305134
DOI: 10.1016/j.ekir.2020.09.023 -
Nature Reviews. Nephrology Aug 2013The glomerular basement membrane (GBM) is the central, non-cellular layer of the glomerular filtration barrier that is situated between the two cellular... (Review)
Review
The glomerular basement membrane (GBM) is the central, non-cellular layer of the glomerular filtration barrier that is situated between the two cellular components--fenestrated endothelial cells and interdigitated podocyte foot processes. The GBM is composed primarily of four types of extracellular matrix macromolecule--laminin-521, type IV collagen α3α4α5, the heparan sulphate proteoglycan agrin, and nidogen--which produce an interwoven meshwork thought to impart both size-selective and charge-selective properties. Although the composition and biochemical nature of the GBM have been known for a long time, the functional importance of the GBM versus that of podocytes and endothelial cells for establishing the glomerular filtration barrier to albumin is still debated. Together with findings from genetic studies in mice, the discoveries of four human mutations affecting GBM components in two inherited kidney disorders, Alport syndrome and Pierson syndrome, support essential roles for the GBM in glomerular permselectivity. Here, we explain in detail the proposed mechanisms whereby the GBM can serve as the major albumin barrier and discuss possible approaches to circumvent GBM defects associated with loss of permselectivity.
Topics: Abnormalities, Multiple; Albumins; Animals; Collagen Type IV; Eye Abnormalities; Glomerular Basement Membrane; Humans; Laminin; Membrane Glycoproteins; Mutation; Myasthenic Syndromes, Congenital; Nephritis, Hereditary; Nephrotic Syndrome; Pupil Disorders
PubMed: 23774818
DOI: 10.1038/nrneph.2013.109 -
Archivos Argentinos de Pediatria Jun 2020Pierson syndrome is characterized by congenital nephrotic syndrome and bilateral microcoria. Genetically, mutations in the LAMB2 gene, which encodes the laminin β2...
Pierson syndrome is characterized by congenital nephrotic syndrome and bilateral microcoria. Genetically, mutations in the LAMB2 gene, which encodes the laminin β2 chain, lead to this disorder. To date, 98 cases and 50 different mutations have been reported in literature. There are no specific therapies for Pierson syndrome and treatment is supportive. The prognosis is poor because of progressive impairment of renal function and complications of renal failure. We report a novel homozygous mutation (c.1890G>T, p.Q630H) in the LAMB2 gene in a patient with Pierson syndrome who had atypical phenotypic feature such as epidermolysis bullosa.
Topics: Female; Genetic Markers; Homozygote; Humans; Infant; Laminin; Mutation; Myasthenic Syndromes, Congenital; Nephrotic Syndrome; Phenotype; Pupil Disorders
PubMed: 32470267
DOI: 10.5546/aap.2020.eng.e288 -
Seminars in Nephrology Jul 2012This article summarizes the basic cellular and extracellular events in the development of the glomerulus and assembly of the glomerular basement membrane (GBM), paying... (Review)
Review
This article summarizes the basic cellular and extracellular events in the development of the glomerulus and assembly of the glomerular basement membrane (GBM), paying special attention to laminin (LM) and type IV collagen. Cellular receptors for GBM proteins, including the integrins, dystroglycan, and discoidin domain receptor 1 also are discussed. Evidence is reviewed showing that the laminin isoform present in the earliest GBM, LM-111, and final isoform found in the mature GBM, LM-521, are each derived from both endothelial cells and podocytes. Although the early collagen α1α2α1(IV) similarly derives from endothelial cells and podocytes, collagen α3α4α5(IV) found in fully mature GBM is a product solely of podocytes. Genetic diseases affecting laminin and type IV collagen synthesis also are presented, with an emphasis on mutations to LAMB2 (Pierson syndrome) and COL4A3, COL4A4, and COL4A5 (Alport syndrome), and their experimental mouse models. Stress is placed on the assembly of a compositionally correct GBM for the acquisition and maintenance of glomerular barrier properties.
Topics: Animals; Collagen Type IV; Endothelium; Glomerular Basement Membrane; Heparan Sulfate Proteoglycans; Humans; Kidney Diseases; Laminin; Podocytes
PubMed: 22958488
DOI: 10.1016/j.semnephrol.2012.06.005 -
Matrix Biology : Journal of the... Apr 2018Laminin polymerization is a key step of basement membrane self-assembly that depends on the binding of the three different N-terminal globular LN domains. Several...
Laminin polymerization is a key step of basement membrane self-assembly that depends on the binding of the three different N-terminal globular LN domains. Several mutations in the LN domains cause LAMA2-deficient muscular dystrophy and LAMB2-deficient Pierson syndrome. These mutations may affect polymerization. A novel approach to identify the amino acid residues required for polymerization has been applied to an analysis of these and other laminin LN mutations. The approach utilizes laminin-nidogen chimeric fusion proteins that bind to recombinant non-polymerizing laminins to provide a missing functional LN domain. Single amino acid substitutions introduced into these chimeras were tested to determine if polymerization activity and the ability to assemble on cell surfaces were lost. Several laminin-deficient muscular dystrophy mutations, renal Pierson syndrome mutations, and Drosophila mutations causing defects of heart development were identified as ones causing loss of laminin polymerization. In addition, two novel residues required for polymerization were identified in the laminin γ1 LN domain.
Topics: Abnormalities, Multiple; Amino Acid Motifs; Animals; Basement Membrane; Drosophila; Drosophila Proteins; Eye Abnormalities; HEK293 Cells; Humans; Laminin; Membrane Glycoproteins; Models, Molecular; Muscular Dystrophies; Mutation; Myasthenic Syndromes, Congenital; Nephrotic Syndrome; Protein Binding; Protein Multimerization; Pupil Disorders; Recombinant Fusion Proteins
PubMed: 29408412
DOI: 10.1016/j.matbio.2018.01.012 -
The Journal of Pathology May 2014The study of mutations causing the steroid-resistant nephrotic syndrome in children has greatly advanced our understanding of the kidney filtration barrier. In...
The study of mutations causing the steroid-resistant nephrotic syndrome in children has greatly advanced our understanding of the kidney filtration barrier. In particular, these genetic variants have illuminated the roles of the podocyte, glomerular basement membrane and endothelial cell in glomerular filtration. However, in a significant number of familial and early onset cases, an underlying mutation cannot be identified, indicating that there are likely to be multiple unknown genes with roles in glomerular permeability. We now show how the combination of N-ethyl-N-nitrosourea mutagenesis and next-generation sequencing could be used to identify the range of mutations affecting these pathways. Using this approach, we isolated a novel mouse strain with a viable nephrotic phenotype and used whole-genome sequencing to isolate a causative hypomorphic mutation in Lamb2. This discovery generated a model for one part of the spectrum of human Pierson's syndrome and provides a powerful proof of principle for accelerating gene discovery and improving our understanding of inherited forms of renal disease.
Topics: Abnormalities, Multiple; Animals; DNA Mutational Analysis; Disease Models, Animal; Ethylnitrosourea; Eye Abnormalities; Genetic Association Studies; Genetic Predisposition to Disease; High-Throughput Nucleotide Sequencing; Kidney Tubules; Laminin; Mice; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Mutant Strains; Mutation; Myasthenic Syndromes, Congenital; Nephrotic Syndrome; Pedigree; Phenotype; Proteinuria; Pupil Disorders
PubMed: 24293254
DOI: 10.1002/path.4308 -
Kidney International Reports Sep 2023Laminin subunit beta-2 -associated disease, termed Pierson syndrome, presents with congenital nephrotic syndrome, ocular symptoms, and neuromuscular symptoms. In recent...
INTRODUCTION
Laminin subunit beta-2 -associated disease, termed Pierson syndrome, presents with congenital nephrotic syndrome, ocular symptoms, and neuromuscular symptoms. In recent years, however, the widespread use of next-generation sequencing (NGS) has helped to discover a variety of phenotypes associated with this disease. Therefore, we conducted this systematic review.
METHODS
A literature search of patients with variants was conducted, and 110 patients were investigated, including 12 of our patients. For genotype-phenotype correlation analyses, the extracted data were investigated for pathogenic variant types, the severity of nephropathy, and extrarenal symptoms. Survival analyses were also performed for the onset age of end-stage kidney disease (ESKD).
RESULTS
Among all patients, 81 (78%) presented with congenital nephrotic syndrome, and 52 (55%) developed ESKD within 12 months. The median age at ESKD onset was 6.0 months. Kidney survival analysis showed that patients with biallelic truncating variants had a significantly earlier progression to ESKD than those with other variants (median age 1.2 months vs. 60.0 months, < 0.05). Although the laminin N-terminal domain is functionally important in laminin proteins, and variants in the laminin N-terminal domain are said to result in a severe kidney phenotype such as earlier onset age and worse prognosis, there were no significant differences in onset age of nephropathy and progression to ESKD between patients with nontruncating variants located in the laminin N-terminal domain and those with variants located outside this domain.
CONCLUSION
This study revealed a diversity of -associated diseases, characteristics of nephropathy, and genotype-phenotype correlations.
PubMed: 37705905
DOI: 10.1016/j.ekir.2023.06.019 -
Proceedings of the National Academy of... Sep 2011Pierson syndrome is a congenital nephrotic syndrome with ocular and neurological defects caused by mutations in LAMB2, the gene encoding the basement membrane protein...
Pierson syndrome is a congenital nephrotic syndrome with ocular and neurological defects caused by mutations in LAMB2, the gene encoding the basement membrane protein laminin β2 (Lamβ2). It is the kidney glomerular basement membrane (GBM) that is defective in Pierson syndrome, as Lamβ2 is a component of laminin-521 (LM-521; α5β2γ1), the major laminin in the mature GBM. In both Pierson syndrome and the Lamb2(-/-) mouse model for this disease, laminin β1 (Lamβ1), a structurally similar homolog of Lamβ2, is marginally increased in the GBM, but it fails to fully compensate for the loss of Lamβ2, leading to the filtration barrier defects and nephrotic syndrome. Here we generated several lines of Lamβ1 transgenic mice and used them to show that podocyte-specific Lamβ1 expression in Lamb2(-/-) mice abrogates the development of nephrotic syndrome, correlating with a greatly extended lifespan. In addition, the more Lamβ1 was expressed, the less urinary albumin was excreted. Transgenic Lamβ1 expression increased the level of Lamα5 in the GBM of rescued mice, consistent with the desired increased deposition of laminin-511 (α5β1γ1) trimers. Ultrastructural analysis revealed occasional knob-like subepithelial GBM thickening but intact podocyte foot processes in aged rescued mice. These results suggest the possibility that up-regulation of LAMB1 in podocytes, should it become achievable, would likely lessen the severity of nephrotic syndrome in patients carrying LAMB2 mutations.
Topics: Abnormalities, Multiple; Animals; Capillaries; Disease Models, Animal; Eye Abnormalities; Glomerular Basement Membrane; Glomerular Filtration Rate; Humans; Infant; Laminin; Mice; Mice, Transgenic; Myasthenic Syndromes, Congenital; Nephrotic Syndrome; Podocytes; Pupil Disorders; Survival Analysis; Time Factors
PubMed: 21876163
DOI: 10.1073/pnas.1108269108