Transforming Growth Factor Β-induced Gene Research Articles

An Arg124Cys mutation in transforming growth factor β-induced gene associated with lattice corneal dystrophy type I in a Chinese pedigree.

Purpose:To identify a clinical and genetic form of a large Chinese family with an autosomal-dominant lattice corneal dystrophy type I (LCD I).Methods:The patients’ eyes were examined on the basis of slit-lamp microscopy, and other clinical records were also collected. Genomic DNA was extracted from peripheral leukocytes of the affected patients and their unaffected family members. Each previous reported mutation of the transforming growth factor β-induced gene (TGFBI) gene was amplified by touch-down polymerase chain reaction and directly sequenced to verify the disease-causing mutation.Results:Typical clinical features of LCD I were found by slit-lamp photography in these affected Chinese pedigrees. A heterozygous single base-pair transition from C to T (c.418 C > T), leading to amino acid substitution Arg124Cys (R124C) in the encoded TGFBI protein, was detected in all of the eighteen affected patients. The same mutation was not found in unaffected family members.Conclusion:The R124C mutation hot spot, which was relatively rare in China, was responsible for LCD I in the large family. Molecular genetic analysis of TGFBI gene can offer an accurate diagnosis of patients with lattice corneal dystrophies in the clinical treatment.

Prevalence of transforming growth factor β–induced gene corneal dystrophies in Chinese refractive surgery candidates

To determine the prevalence of the transforming growth factor (TGF) β-induced gene corneal dystrophies in refractive surgery candidates in China. Five hospitals in China. Prospective case series. Refractive surgical candidates from 5 preselected eye hospitals/centers in China were recruited after providing informed consent. All patients had slitlamp biomicroscopy and collection of a buccal swab as a source of DNA for screening of the TGF β-induced gene for the 5 most common mutations associated with Reis-Bückler corneal dystrophy, Thiel-Behnke corneal dystrophy, granular corneal dystrophy type 1, granular corneal dystrophy type 2, and lattice corneal dystrophy type1. Of the 2068 refractive surgery candidates analyzed, 4 had corneal opacities in both eyes on slitlamp examination. Screening for the TGF β-induced gene found the heterozygous p.R124H mutation associated with granular corneal dystrophy type 2 in each of the 4 individuals with corneal opacities as well as in a fifth individual who did not have any corneal opacities, for a prevalence of 0.24%. Exacerbation of dystrophic corneal deposition developed after laser refractive surgery in 2 individuals who did not have preoperative TGF β-induced gene screening. The prevalence of the TGF β-induced gene corneal dystrophies in Chinese refractive surgery candidates was estimated to be approximately 0.24%. Genetic testing is recommended to identify and exclude from candidacy all individuals with a TGF β-induced gene dystrophy before elective keratorefractive surgery to avoid causing accelerated postoperative dystrophic deposition.

Vortex Pattern of Corneal Deposits in Granular Corneal Dystrophy Associated With the p.(Arg555Trp) Mutation in TGFBI.

To describe 2 unrelated families with multiple members demonstrating a less commonly recognized vortex pattern of corneal deposits confirmed to be granular corneal dystrophy type 1 (GCD1) after identification of the p.(Arg555Trp) mutation in the transforming growth factor β-induced gene (TGFBI). A slit-lamp examination was performed on individuals from 2 families, one of Mexican descent and a second of Italian descent. After DNA extraction from affected individuals and their unaffected relatives, TGFBI screening was performed. Eight of 20 individuals in the Mexican family and 20 of 55 in the Italian family demonstrated corneal stromal opacities. Seven of the 8 affected individuals in the Mexican family and 4 of the 20 affected individuals in the Italian family demonstrated a phenotype characterized by a "sea fan" or vortex pattern of superficial stromal corneal deposits originating from the inferior aspect of the cornea. Screening of TGFBI in both families revealed a heterozygous missense mutation [p.(Arg555Trp)] in exon 12, confirming the diagnosis of GCD1. Our findings demonstrate that GCD1 may present with a vortex pattern of anterior stromal deposits. Although this pattern of dystrophic deposits is not recognized by clinicians as a typical phenotype of GCD1, it is consistent with the production of the majority of the TGFBI protein by the corneal epithelium.

Mutation Analysis of the TGFBI Gene in Consecutive Korean Patients With Corneal Dystrophies.

BackgroundMutations in the transforming growth factor β-induced gene (TGFBI) are major causes of genetic corneal dystrophies (CDs), which can be grouped into TGFBI CDs. Although a few studies have reported the clinical and genetic features of Korean patients with TGFBI CD, no data are available regarding the frequency and spectrum of TGFBI mutations in a consecutive series of Korean patients with clinically diagnosed CDs.MethodsPatients with any type of CD, who underwent both ophthalmologic examination and TGFBI gene analysis by Sanger sequencing at a tertiary care hospital in Seoul, Korea from 2006 to 2013, were enrolled in this study.ResultsAmong a total of 89 patients, 77 (86.5%) were diagnosed as having clinical TGFBI CD. Seventy-three out of 74 patients (98.6%) with granular CD type 2 (GCD2), had the p.R124H mutation. Of particular note, one patient with rapidly progressive CD had the p.R124H mutation as well as a novel nonsense variant with unknown clinical significance (p.A179*). In three patients with lattice CD type 1 (LCD1), one known mutation (p.R124C) and two novel variants (p.L569Q and p.T621P) in the TGFBI gene were identified.ConclusionsThis study provides epidemiological insight into CDs in a Korean population and reaffirms that GCD2 is the most common TGFBI CD phenotype and that p.R124H is the only mutation identified in patients with GCD2. In addition, we broaden the spectrum of TGFBI mutations by identifying two novel missense variants in patients with LCD1.

The Transcription Factor GLI1 Interacts with SMAD Proteins to Modulate Transforming Growth Factor β-Induced Gene Expression in a p300/CREB-binding Protein-associated Factor (PCAF)-dependent Manner

The biological role of the transcription factor GLI1 in the regulation of tumor growth is well established; however, the molecular events modulating this phenomenon remain elusive. Here, we demonstrate a novel mechanism underlying the role of GLI1 as an effector of TGFβ signaling in the regulation of gene expression in cancer cells. TGFβ stimulates GLI1 activity in cancer cells and requires its transcriptional activity to induce BCL2 expression. Analysis of the mechanism regulating this interplay identified a new transcriptional complex including GLI1 and the TGFβ-regulated transcription factor, SMAD4. We demonstrate that SMAD4 physically interacts with GLI1 for concerted regulation of gene expression and cellular survival. Activation of the TGFβ pathway induces GLI1-SMAD4 complex binding to the BCL2 promoter whereas disruption of the complex through SMAD4 RNAi depletion impairs GLI1-mediated transcription of BCL2 and cellular survival. Further characterization demonstrated that SMAD2 and the histone acetyltransferase, PCAF, participate in this regulatory mechanism. Both proteins bind to the BCL2 promoter and are required for TGFβ- and GLI1-stimulated gene expression. Moreover, SMAD2/4 RNAi experiments showed that these factors are required for the recruitment of GLI1 to the BCL2 promoter. Finally, we determined whether this novel GLI1 transcriptional pathway could regulate other TGFβ targets. We found that two additional TGFβ-stimulated genes, INTERLEUKIN-7 and CYCLIN D1, are dependent upon the intact GLI1-SMAD-PCAF complex for transcriptional activation. Collectively, these results define a novel epigenetic mechanism that uses the transcription factor GLI1 and its associated complex as a central effector to regulate gene expression in cancer cells.

Comparative transcriptional analysis of three human ligaments with distinct biomechanical properties

One major aim of regenerative medicine targeting the musculoskeletal system is to provide complementary and/or alternative therapeutic approaches to current surgical therapies, often involving the removal and prosthetic substitution of damaged tissues such as ligaments. For these approaches to be successful, detailed information regarding the cellular and molecular composition of different musculoskeletal tissues is required. Ligaments have often been considered homogeneous tissues with common biomechanical properties. However, advances in tissue engineering research have highlighted the functional relevance of the organisational and compositional differences between ligament types, especially in those with higher risks of injury. The aim of this study was to provide information concerning the relative expression levels of a subset of key genes (including extracellular matrix components, transcription factors and growth factors) that confer functional identity to ligaments. We compared the transcriptomes of three representative human ligaments subjected to different biomechanical demands: the anterior cruciate ligament (ACL); the ligamentum teres of the hip (LT); and the iliofemoral ligament (IL). We revealed significant differences in the expression of type I collagen, elastin, fibromodulin, biglycan, transforming growth factor β1, transforming growth interacting factor 1, hypoxia-inducible factor 1-alpha and transforming growth factor β-induced gene between the IL and the other two ligaments. Thus, considerable molecular heterogeneity can exist between anatomically distinct ligaments with differing biomechanical demands. However, the LT and ACL were found to show remarkable molecular homology, suggesting common functional properties. This finding provides experimental support for the proposed role of the LT as a hip joint stabiliser in humans.

A Matrix Metalloproteinase 1–Cleavable Composite Peptide Derived From Transforming Growth Factor β–Inducible Gene h3 Potently Inhibits Collagen‐Induced Arthritis

Transforming growth factor β-inducible gene h3 (βIG-H3), which is abundantly expressed in rheumatoid synovium, and matrix metalloproteinases (MMP) play important roles in the pathogenesis of rheumatoid arthritis (RA). The aim of this study was to determine the therapeutic efficacy of βIG-H3-derived peptides using MMP-1-dependent target tissue delivery in chronic inflammatory arthritis. Peptides developed from βIG-H3 derivatives, including the second and fourth YH peptides, the fourth fas-1 domain, the fourth fas-1 domain truncated for H1 and H2 sequences (dhfas-1), and an MMP-1- cleavable composite peptide (MFK24), were cloned. We confirmed the specificity of MFK24 cleavage by immunoblot analysis after treatment with different proteases. The YH18 peptide in the fourth fas-1 domain of βIG-H3 was weakly effective in suppressing arthritis severity in mice with collagen-induced arthritis (CIA). Treatment with higher-dose dhfas-1 (30 mg/kg) showed remarkable efficacy, whereas treatment with a lower dose (10 mg/kg) resulted in only partial improvement. MFK24, a composite peptide consisting of dhfas-1 and RGD peptide linked by MMP-1 substrate, was cleaved specifically by MMP-1. The adhesion and migration of NIH3T3 cells mediated by βIG-H3 were inhibited by MFK24 at a low concentration. MFK24 suppressed the adhesion of NIH3T3 cells more efficiently compared with murine dhfas-1 (MFK00) or RGD, either alone or in combination. The therapeutic efficacy of MFK24 in mice with CIA was remarkably enhanced, with consistently reduced expression of inflammatory mediators within joint tissue. This proof-of-concept study showed that an MMP-cleavable composite peptide, based on βIG-H3 derivatives, had markedly improved therapeutic efficacy in chronic inflammatory arthritis, implicating a new expandable strategy for enhancement of the efficacy of 2 different active molecules in RA.