Genotypic Categorization of Loeys-Dietz Syndrome Based on 24 Novel Families and Literature Data
GENES
Authors: Camerota, Letizia; Ritelli, Marco; Wischmeijer, Anita; Majore, Silvia; Cinquina, Valeria; Fortugno, Paola; Monetta, Rosanna; Gigante, Laura; Sangiuolo, Federica Carla; Novelli, Giuseppe; Colombi, Marina; Brancati, Francesco; Ruvolo, Giovanni; Bertoldo, Fabio; Donzelli, Concettina; Polisca, Patrizio; Salehi, Leila Baghernajad; Mancino, Raffaele; Di Carlo, Emiliano; Bollero, Patrizio; Cozza, Paola; Lagana, Giuseppina; Farsetti, Pasquale; De Maio, Fernando; De Luna, Vincenzo; Mancini, Federico; Chini, Loredana; Graziani, Simona; Floris, Roberto; Sperandio, Massimiliano; Infante, Angela; De Stefano, Alberto; Chiariello, Luigi; Grego, Susanna
Abstract
Loeys-Dietz syndrome (LDS) is a connective tissue disorder first described in 2005 featuring aortic/arterial aneurysms, dissections, and tortuosity associated with craniofacial, osteoarticular, musculoskeletal, and cutaneous manifestations. Heterozygous mutations in 6 genes (TGFBR1/2, TGFB2/3, SMAD2/3), encoding components of the TGF-beta pathway, cause LDS. Such genetic heterogeneity mirrors broad phenotypic variability with significant differences, especially in terms of the age of onset, penetrance, and severity of life-threatening vascular manifestations and multiorgan involvement, indicating the need to obtain genotype-to-phenotype correlations for personalized management and counseling. Herein, we report on a cohort of 34 LDS patients from 24 families all receiving a molecular diagnosis. Fifteen variants were novel, affecting the TGFBR1 (6), TGFBR2 (6), SMAD3 (2), and TGFB2 (1) genes. Clinical features were scored for each distinct gene and matched with literature data to strengthen genotype-phenotype correlations such as more severe vascular manifestations in TGFBR1/2-related LDS. Additional features included spontaneous pneumothorax in SMAD3-related LDS and cervical spine instability in TGFB2-related LDS. Our study broadens the clinical and molecular spectrum of LDS and indicates that a phenotypic continuum emerges as more patients are described, although genotype-phenotype correlations may still contribute to clinical management.
Sphingosine-1-phosphate induces pro-remodelling response in airway smooth muscle cells
ALLERGY
Authors: Fuerst, E.; Foster, H. R.; Ward, J. P. T.; Corrigan, C. J.; Cousins, D. J.; Woszczek, G.
Abstract
Background: Increased proliferation of airway smooth muscle (ASM) cells leading to hyperplasia and increased ASM mass is one of the most characteristic features of airway remodelling in asthma. A bioactive lipid, sphingosine-l-phosphate (S1P), has been suggested to affect airway remodelling by stimulation of human ASM cell proliferation. Objective: To investigate the effect of SIP on signalling and regulation of gene expression in ASM cells from healthy and asthmatic individuals. Methods: Airway smooth muscle cells grown from bronchial biopsies of healthy and asthmatic individuals were exposed to S1P. Gene expression was analysed using microarray, real-time PCR and Western blotting. Receptor signalling and function were determined by mRNA knockdown and intracellular calcium mobilization experiments. Results: S113 potently regulated the expression of more than 80 genes in human ASM cells, including several genes known to be involved in the regulation of cell proliferation and airway remodelling (HBEGF, TGFB3, TXNIP, PLAUR, SERPINE1, RGS4). S113 acting through S1132 and S1P3 receptors activated intracellular calcium mobilization and extracellular signal-regulated and Rho-associated kinases to regulate gene expression. S1P-induced responses were not inhibited by corticosteroids and did not differ significantly between ASM cells from healthy and asthmatic individuals. Conclusion: SIT induces a steroid-resistant, pro-remodelling pathway in ASM cells. Targeting SIP or its receptors could be a novel treatment strategy for inhibiting airway remodelling in asthma.