Enamel and dental anomalies in latent-transforming growth factor beta-binding protein 3 mutant mice.

Latent-transforming growth factor beta-binding protein 3 (LTBP-3) is important for craniofacial morphogenesis and hard tissue mineralization, as it is essential for activation of transforming growth factor-β (TGF-β). To investigate the role of LTBP-3 in tooth formation we performed micro-computed tomography (micro-CT), histology, and scanning electron microscopy analyses of adult Ltbp3-/- mice. The Ltbp3-/- mutants presented with unique craniofacial malformations and reductions in enamel formation that began at the matrix formation stage. Organization of maturation-stage ameloblasts was severely disrupted. The lateral side of the incisor was affected most. Reduced enamel mineralization, modification of the enamel prism pattern, and enamel nodules were observed throughout the incisors, as revealed by scanning electron microscopy. Molar roots had internal irregular bulbous-like formations. The cementum thickness was reduced, and microscopic dentinal tubules showed minor nanostructural changes. Thus, LTBP-3 is required for ameloblast differentiation and for the formation of decussating enamel prisms, to prevent enamel nodule formation, and for proper root morphogenesis. Also, and consistent with the role of TGF-β signaling during mineralization, almost all craniofacial bone components were affected in Ltbp3-/- mice, especially those involving the upper jaw and snout. This mouse model demonstrates phenotypic overlap with Verloes Bourguignon syndrome, also caused by mutation of LTBP3, which is hallmarked by craniofacial anomalies and amelogenesis imperfecta phenotypes.journal article2017 Febimporte

Mutations in the latent TGF-beta binding protein 3 (LTBP3) gene cause brachyolmia with amelogenesis imperfecta

Inherited dental malformations constitute a clinically and genetically heterogeneous group of disorders. Here, we report on four families, three of them consanguineous, with an identical phenotype, characterized by significant short stature with brachyolmia and hypoplastic amelogenesis imperfecta (AI) with almost absent enamel. This phenotype was first described in 1996 by Verloes et al. as an autosomal recessive form of brachyolmia associated with AI. Whole-exome sequencing resulted in the identification of recessive hypomorphic mutations including deletion, nonsense and splice mutations, in the LTBP3 gene, which is involved in the TGF-beta signaling pathway. We further investigated gene expression during mouse development and tooth formation. Differentiated ameloblasts synthesizing enamel matrix proteins and odontoblasts expressed the gene. Study of an available knockout mouse model showed that the mutant mice displayed very thin to absent enamel in both incisors and molars, hereby recapitulating the AI phenotype in the human disorder

Synthesis of 5-azaandrostane-3b,17b-diol protected at the 17b-hydroxyl group

In the present paper, the preparation of 3b-hydroxy-17b-dimethyl-tert-butylsilyloxy-5-azaandrostane (15) in fourteen steps is described. B-nor-17-oxoandrost-5-en-3b-yl acetate (1) was used as the starting material, which was transformed to the key intermediate of the synthesis, B-nor-17b-dimethyl-tert-butylsilyloxyandrost-4-en-3b-yl acetate (7)

5,10:13,14-Disecosteroids: novel modified steroids containing 10- and 9-membered rings

In this paper a synthetic pathway to the modified 5,10 13,14-bisfragmentation cholestane derivatives 8-14 is described. The synthesis involves introduction of the 5 alpha- and 14 alpha-hydroxyl groups in the cholestane molecule and Subsequent cleavage of the C(5)-C(10) bond in 5 alpha,14 alpha-dihydroxycholestan-3 beta-yl acetate (4) with the HgO/I-2 reagent and the C(13)-C( 14) bond in the stereoisomeric 14 alpha-hydroxy-5,10-secosteroids 5 and 6 with the Pb(OAc)(4)/I-2 reagent Complete and Unambiguous H-1 and C-13 NMR resonance assignments of the obtained secosteroids. as well as the Solution conformations of then 10- and 9-membered rings were determined by extensive analysis of 1D and 2D NMR spectral data The structures and the solid-state conformations of 5,10-secosteroids 5-7 were confirmed by X-ray analysis All diseco-compounds have a novel 5.10 13,14-disecocholestane skeleton. (C) 2009 Elsevier Ltd. All rights reserve

Contemporary review on spontaneous coronary artery dissection: insights into the angiographic finding and differential diagnosis

2023 Kovacevic, Jarakovic, Milovancev, Cankovic, Petrovic, Bjelobrk, Ilic, Srdanovic, Tadic, Dabovic, Crnomarkovic, Komazec, Dracina, Apostolovic, Stanojevic and Kunadian.Spontaneous coronary artery dissection (SCAD), although in the majority of cases presents as an acute coronary syndrome (ACS), has different pathophysiology from atherosclerosis that influences specific angiography findings and enables most patients to be solved by optimal medical therapy rather than percutaneous coronary intervention (PCI). Therefore, accurate diagnosis is essential for adequate treatment of each patient as management of SCAD differs from that of ACS of atherosclerotic aetiology. So far, invasive coronary angiography remains the most important diagnostic tool in suspected SCAD. However, there are ambiguous cases that can mimic SCAD. In this review, the authors summarize current knowledge about the diagnostic algorithms, particularly angiographic features of SCAD, pitfalls of angiography, and the role of intracoronary imaging in the context of SCAD diagnosis. Finally, apart from the pathognomonic angiographic features of SCAD that are thoroughly discussed in this review, the authors focus on obscure angiography findings and findings that can mimic SCAD as well. Differential diagnosis and the timely recognition of SCAD are crucial as there are differences in the acute and long-term management of SCAD and other causes of ACS

Perturbation of transforming growth factor (TGF)-ß1 association with latent TGF-β binding protein yields inflammation and tumors

Transforming growth factor-β (TGF-β) activity is controlled at many levels including the conversion of the latent secreted form to its active state. TGF-β is often released as part of an inactive tripartite complex consisting of TGF-β, the TGF-β propeptide, and a molecule of latent TGF-β binding protein (LTBP). The interaction of TGF-β and its cleaved propeptide renders the growth factor latent, and the liberation of TGF-β from this state is crucial for signaling. To examine the contribution of LTBP to TGF-β function, we generated mice in which the cysteines that link the propeptide to LTBP were mutated to serines, thereby blocking covalent association. Tgfb1C33S/C33S mice had multiorgan inflammation, lack of skin Langerhans cells (LC), and a shortened lifespan, consistent with decreased TGF-β1 levels. However, the inflammatory response and decreased lifespan were not as severe as observed with Tgfb1−/− animals. Tgfb1C33S/C33S mice exhibited decreased levels of active TGF-β1, decreased TGF-β signaling, and tumors of the stomach, rectum, and anus. These data suggest that the association of LTBP with the latent TGF-β complex is important for proper TGF-β1 function and that Tgfb1C33S/C33S mice are hypomorphs for active TGF-β1. Moreover, although mechanisms exist to activate latent TGF-β1 in the absence of LTBP, these mechanisms are not as efficient as those that use the latent complex containing LTBP

Mutations in LTBP4 Cause a Syndrome of Impaired Pulmonary, Gastrointestinal, Genitourinary, Musculoskeletal, and Dermal Development

We report recessive mutations in the gene for the latent transforming growth factor-β binding protein 4 (LTBP4) in four unrelated patients with a human syndrome disrupting pulmonary, gastrointestinal, urinary, musculoskeletal, craniofacial, and dermal development. All patients had severe respiratory distress, with cystic and atelectatic changes in the lungs complicated by tracheomalacia and diaphragmatic hernia. Three of the four patients died of respiratory failure. Cardiovascular lesions were mild, limited to pulmonary artery stenosis and patent foramen ovale. Gastrointestinal malformations included diverticulosis, enlargement, tortuosity, and stenosis at various levels of the intestinal tract. The urinary tract was affected by diverticulosis and hydronephrosis. Joint laxity and low muscle tone contributed to musculoskeletal problems compounded by postnatal growth delay. Craniofacial features included microretrognathia, flat midface, receding forehead, and wide fontanelles. All patients had cutis laxa. Four of the five identified LTBP4 mutations led to premature termination of translation and destabilization of the LTBP4 mRNA. Impaired synthesis and lack of deposition of LTBP4 into the extracellular matrix (ECM) caused increased transforming growth factor-β (TGF-β) activity in cultured fibroblasts and defective elastic fiber assembly in all tissues affected by the disease. These molecular defects were associated with blocked alveolarization and airway collapse in the lung. Our results show that coupling of TGF-β signaling and ECM assembly is essential for proper development and is achieved in multiple human organ systems by multifunctional proteins such as LTBP4

F-Spondin Deficient Mice Have a High Bone Mass Phenotype

F-spondin is a pericellular matrix protein upregulated in developing growth plate cartilage and articular cartilage during osteoarthritis. To address its function in bone and cartilage in vivo, we generated mice that were deficient for the F-spondin gene, Spon1. Spon1-/- mice were viable and developed normally to adulthood with no major skeletal abnormalities. At 6 months, femurs and tibiae of Spon1-/- mice exhibited increased bone mass, evidenced by histological staining and micro CT analyses, which persisted up to 12 months. In contrast, no major abnormalities were observed in articular cartilage at any age group. Immunohistochemical staining of femurs and tibiae revealed increased levels of periostin, alkaline phosphate and tartrate resistant acid phosphatase (TRAP) activity in the growth plate region of Spon1-/- mice, suggesting elevated bone synthesis and turnover. However, there were no differences in serum levels of TRAP, the bone resorption marker, CTX-1, or osteoclast differentiation potential between genotypes. Knockout mice also exhibited reduced levels of TGF-β1 in serum and cultured costal chondrocytes relative to wild type. This was accompanied by increased levels of the BMP-regulatory SMADs, P-SMAD1/5 in tibiae and chondrocytes. Our findings indicate a previously unrecognized role for Spon1 as a negative regulator of bone mass. We speculate that Spon1 deletion leads to a local and systemic reduction of TGF-β levels resulting in increased BMP signaling and increased bone deposition in adult mice