Skin fibroblasts of patients with geleophysic dysplasia due to <i>FBN1</i> mutations have lysosomal inclusions and losartan improves their microfibril deposition defect

Piccolo, Pasquale; Sabatino, Valeria; Mithbaokar, Pratibha; Polishchuk, Elena; Hicks, John; Polishchuk, Roman; Bacino, Carlos A.; Brunetti‐Pierri, Nicola

doi:10.1002/mgg3.844

Cited by 8 publications

(9 citation statements)

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“…Similar inclusions were also found in bronchial epithelial cells of Adamtsl2 − / − mouse, thus suggesting glycogen storage [8]. Moreover, we previously found that inclusions are also present in fibroblasts of GPHYSD patients carrying FBN1 mutations and Myhre syndrome (MIM139210) patients carrying SMAD4 mutations [26], suggesting that a common pathway is responsible for the formation of such inclusions. Here, we showed that lysosomal inclusions do not appear to contain mutant ADAMTSL2.…”

Section: Discussionsupporting

confidence: 55%

“…Intracellular inclusion bodies were previously reported in GPHYSD cases [2,24,25] and we recently found that storage occurs within lysosomes in GPHYSD cells carrying FBN1 mutation [26]. Primary fibroblasts from skin biopsy available only for subject 3 were analyzed by EM and showed lysosomal-like vesicles with lamellar structure appearance and electron-dense storage material (Fig.…”

Section: Resultsmentioning

confidence: 81%

“…Primary fibroblasts from skin biopsy available only for subject 3 were analyzed by EM and showed lysosomal-like vesicles with lamellar structure appearance and electron-dense storage material (Fig. 2) suggesting that inclusions are a feature of GPHYSD cells either carrying ADAMTSL2 or FBN1 mutations [26].

Fig.…”

Section: Resultsmentioning

confidence: 99%

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Geleophysic dysplasia: novel missense variants and insights into ADAMTSL2 intracellular trafficking

Piccolo

Sabatino

Mithbaokar

et al. 2019

Molecular Genetics and Metabolism Reports

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Geleophysic dysplasia (GPHYSD1, MIM231050; GPHYSD2, MIM614185; GPHYSD3, MIM617809) is an autosomal disorder characterized by short-limb dwarfism, brachydactyly, cardiac valvular disease, and laryngotracheal stenosis. Mutations in ADAMTSL2 , FBN1 , and LTBP3 genes are responsible for this condition. We found that three previously described cases of GPHYSD diagnosed clinically were homozygote or compound heterozygotes for five ADAMTSL2 variants, four of which not being previously reported. By electron microscopy, skin fibroblasts available in one case homozygote for an ADAMTSL2 variant showed a defective intracellular localization of mutant ADAMTSL2 protein that did not accumulate within lysosome-like intra-cytoplasmic inclusions. Moreover, this mutant ADAMTSL2 protein was less secreted in medium and resulted in increased SMAD2 phosphorylation in transfected HEK293 cells.

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Section: Discussionsupporting

confidence: 55%

Section: Resultsmentioning

confidence: 81%

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Geleophysic dysplasia: novel missense variants and insights into ADAMTSL2 intracellular trafficking

Piccolo

Sabatino

Mithbaokar

et al. 2019

Molecular Genetics and Metabolism Reports

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“…Losartan potassium salt (Sigma Aldrich, Milan, Italy) was dissolved into dimethyl sulfoxide (DMSO) (Sigma Aldrich, Milan, Italy) and used at the concentration of 200 µM for 14 days on controls’ and patient’s fibroblast cultures as reported in [ 64 , 65 ]. Skin fibroblast cell cultures from the patient and control at 2 passages were seeded (2 × 10 5 cells/mL in six-well plates) and after 24 h were incubated with losartan in a single dose in DMEM/F-12 with 20% FBS medium.…”

Section: Methodsmentioning

confidence: 99%

Pro-Fibrotic Phenotype in a Patient with Segmental Stiff Skin Syndrome via TGF-β Signaling Overactivation

Fusco

Nardella

Augello

et al. 2020

IJMS

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Transforming growth factor β (TGF-β) superfamily signaling pathways are ubiquitous and essential for several cellular and physiological processes. The overexpression of TGF-β results in excessive fibrosis in multiple human disorders. Among them, stiff skin syndrome (SSS) is an ultrarare and untreatable condition characterized by the progressive thickening and hardening of the dermis, and acquired joint limitations. SSS is distinct in a widespread form, caused by recurrent germline variants of FBN1 encoding a key molecule of the TGF-β signaling, and a segmental form with unknown molecular basis. Here, we report a 12-year-old female with segmental SSS, affecting the right upper limb with acquired thickening of the dermis evident at the magnetic resonance imaging, and progressive limitation of the elbow and shoulder. To better explore the molecular and cellular mechanisms that drive segmental SSS, several functional studies on patient’s fibroblasts were employed. We hypothesized an impairment of TGF-β signaling and, consequently, a dysregulation of the associated downstream signaling. Lesional fibroblast studies showed a higher phosphorylation level of extracellular signal-regulated kinase 1/2 (ERK1/2), increased levels of nuclear factor-kB (NFkB), and a nuclear accumulation of phosphorylated Smad2 via Western blot and microscopy analyses. Quantitative PCR expression analysis of genes encoding key extracellular matrix proteins revealed increased levels of COL1A1, COL3A1, AGT, LTBP and ITGB1, while zymography assay reported a reduced metalloproteinase 2 enzymatic activity. In vitro exposure of patient’s fibroblasts to losartan led to the partial restoration of normal transforming growth factor β (TGF-β) marker protein levels. Taken together, these data demonstrate that in our patient, segmental SSS is characterized by the overactivation of multiple TGF-β signaling pathways, which likely results in altered extracellular matrix composition and fibroblast homeostasis. Our results for the first time reported that aberrant TGF-β signaling may drive the pathogenesis of segmental SSS and might open the way to novel therapeutic approaches.

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“…Cultured aortic vascular smooth muscle cells were used to explore extracellular matrix abnormalities associated with MFS and bicuspid aortic valve ( Nataatmadja et al 2003 ). Fibroblasts from a patient with geleophysic dysplasia due to a variant in FBN1 were used to test the effect of losartan treatment and results suggested that this would be a promising treatment for these patients ( Piccolo et al 2019 ). FBN2 is also expressed by fibroblasts and its role in the response to hypoxia has been investigated in fibroblast cultures ( Boizot et al 2022 ).…”

Section: Other Potential Models For Fibrillinopathiesmentioning

confidence: 99%

Genetic models of fibrillinopathies

Summers

2023

Genetics

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The fibrillinopathies represent a group of diseases in which the 10–12 nm extracellular microfibrils are disrupted by genetic variants in one of the genes encoding fibrillin molecules, large glycoproteins of the extracellular matrix. The best-known fibrillinopathy is Marfan syndrome, an autosomal dominant condition affecting the cardiovascular, ocular, skeletal, and other systems, with a prevalence of around 1 in 3,000 across all ethnic groups. It is caused by variants of the FBN1 gene, encoding fibrillin-1, which interacts with elastin to provide strength and elasticity to connective tissues. A number of mouse models have been created in an attempt to replicate the human phenotype, although all have limitations. There are also natural bovine models and engineered models in pig and rabbit. Variants in FBN2 encoding fibrillin-2 cause congenital contractural arachnodactyly and mouse models for this condition have also been produced. In most animals, including birds, reptiles, and amphibians, there is a third fibrillin, fibrillin-3 (FBN3 gene) for which the creation of models has been difficult as the gene is degenerate and nonfunctional in mice and rats. Other eukaryotes such as the nematode C. elegans and zebrafish D. rerio have a gene with some homology to fibrillins and models have been used to discover more about the function of this family of proteins. This review looks at the phenotype, inheritance, and relevance of the various animal models for the different fibrillinopathies.

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Skin fibroblasts of patients with geleophysic dysplasia due to FBN1 mutations have lysosomal inclusions and losartan improves their microfibril deposition defect

Cited by 8 publications

References 20 publications

Geleophysic dysplasia: novel missense variants and insights into ADAMTSL2 intracellular trafficking

Geleophysic dysplasia: novel missense variants and insights into ADAMTSL2 intracellular trafficking

Pro-Fibrotic Phenotype in a Patient with Segmental Stiff Skin Syndrome via TGF-β Signaling Overactivation

Genetic models of fibrillinopathies

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