Tendon Extracellular Matrix Remodeling and Defective Cell Polarization in the Presence of Collagen VI Mutations
CELLS
Authors: Antoniel, Manuela; Traina, Francesco; Merlini, Luciano; Andrenacci, Davide; Tigani, Domenico; Santi, Spartaco; Cenni, Vittoria; Sabatelli, Patrizia; Faldini, Cesare; Squarzoni, Stefano
Abstract
Mutations in collagen VI genes cause two major clinical myopathies, Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD), and the rarer myosclerosis myopathy. In addition to congenital muscle weakness, patients affected by collagen VI-related myopathies show axial and proximal joint contractures, and distal joint hypermobility, which suggest the involvement of tendon function. To gain further insight into the role of collagen VI in human tendon structure and function, we performed ultrastructural, biochemical, and RT-PCR analysis on tendon biopsies and on cell cultures derived from two patients affected with BM and UCMD. In vitro studies revealed striking alterations in the collagen VI network, associated with disruption of the collagen VI-NG2 (Collagen VI-neural/glial antigen 2) axis and defects in cell polarization and migration. The organization of extracellular matrix (ECM) components, as regards collagens I and XII, was also affected, along with an increase in the active form of metalloproteinase 2 (MMP2). In agreement with the in vitro alterations, tendon biopsies from collagen VI-related myopathy patients displayed striking changes in collagen fibril morphology and cell death. These data point to a critical role of collagen VI in tendon matrix organization and cell behavior. The remodeling of the tendon matrix may contribute to the muscle dysfunction observed in BM and UCMD patients.
Adipocyte enhancer binding protein 1 (AEBP1) knockdown suppresses human glioma cell proliferation, invasion and induces early apoptosis
PATHOLOGY RESEARCH AND PRACTICE
Authors: Cheng, Limin; Shao, Xuefei; Wang, Qifu; Jiang, Xiaochun; Dai, Yi; Chen, Sansong
Abstract
Background: Glioma is the most common primary malignant tumor with poor prognosis due to the lack of understanding the mechanism underlying the disease and the early diagnosis indexs. It is necessary to identify molecular signatures for predicting the overall prognosis of glioma. Adipocyte enhancer binding protein1 (AEBP1) acts as a transcriptional repressor and plays a role in adipogenesis and smooth muscle cell differentiation. However, its role in glioma remains unclear. Materials and methods: AEBP1 expression was analyzed by bioinformatics using the public database and by qPCR and western blotting in human glioma tissues. AEBP1 downregulation was performed by lipofectamine3000-mediated siRNA transfection. Cell proliferation and invasion were determined by cell counting kit-8 and transwell assays, while early cell apoptosis was determined by flow cytometry. The proteins of downstream NF-kappa B signaling pathway were determined by western blotting. Results: AEBP1 is highly expressed in human gliomas. Lipofectamine 3000-mediated siRNA transfection stably and efficiently suppressed AEBP1 mRNA and protein expression in human glioma cells. AEBP1 downregulation inhibited cell proliferation and invasion, but promoted early cell apoptosis. Also, AEBP1 knockdown in glioma cells decreased the expression of NF-kappa B1. Furthermore, the downstream of NF-kappa B signaling pathway, Bax, caspase-3 are increased, while MMP2 and Bcl-2 are decreased in glioma cells. Conclusion: Elevated AEBP1 is positively associated with poor prognosis of glioma. AEBP1 downregulation suppressed cell proliferation and invasion, but promoted early cell apoptosis. AEBP1 downregulation suppressed the cell proliferation and invasion may by inhibiting the NF-kappa B signaling pathway.