Aortic aneurysms are age-linked aortic dilations that progress silently and carry high mortality rates following rupture. Immune cells are recognized drivers of aneurysm pathogenesis. Clonal hematopoi Show more
Aortic aneurysms are age-linked aortic dilations that progress silently and carry high mortality rates following rupture. Immune cells are recognized drivers of aneurysm pathogenesis. Clonal hematopoiesis is an age-related expansion of somatically mutated hematopoietic stem cells that reshapes immune function and contributes to diverse age-associated diseases. However, its contribution to aneurysm pathogenesis remains unclear. In this study, targeted ultradeep sequencing of patient specimens revealed a high prevalence of clonal hematopoiesis-associated mutations that correlated with faster aneurysm expansion. Thus, we modeled clonal hematopoiesis by competitively transplanting ten-eleven translocation 2-deficient (Tet2-deficient) bone marrow into apoliprotein E-KO (Apoe-KO) mice and induced aneurysms with angiotensin II. Mice with Tet2 clonal hematopoiesis developed significantly greater aortic dilation than did controls. Interestingly, Tet2-deficient macrophages adopted an acid phosphatase 5, tartrate resistant (ACP5+), osteoclast-like state and produced more matrix metalloproteinase 9 (MMP9). Both genetic and pharmacological inhibition of osteoclast-like differentiation suppressed the Tet2-mediated aneurysmal growth in vivo. Thus, Tet2-driven clonal hematopoiesis accelerated aortic aneurysm progression through MMP9-producing, osteoclast-like macrophages and therefore represents a tractable therapeutic axis. Show less
The Wnt pathway is involved in carcinogenesis and three regulatory genes of the Wnt pathway, APC, beta-catenin and Axin are mutated in some primary human cancers. Mutations in these genes can impair t Show more
The Wnt pathway is involved in carcinogenesis and three regulatory genes of the Wnt pathway, APC, beta-catenin and Axin are mutated in some primary human cancers. Mutations in these genes can impair the down regulation of beta-catenin, which results in the stabilization of beta-catenin, accumulation of free beta-catenin and subsequent activation of the Wnt pathway. To clarify the genetic alterations of components of the Wnt pathway in oral squamous cell carcinoma (SCC), we examined mutations in the APC, beta-catenin and Axin genes and subcellular localization of beta-catenin. 20 oral SCC tissues and four cell lines derived from oral SCC were used. Mutational analysis was performed by a single-strand conformation polymorphism (SSCP) method and direct sequencing analysis. The samples were also examined by immunohistochemical staining and immunoblot analysis. In 3 of 4 cell lines, mutations were observed in the APC and Axin1 genes without amino acid substitutions. In a clinical sample, a mutation in the Axin1 gene was detected; a T insertion at codon 250 resulted in the formation of a stop codon at codon 259. In addition, cytoplasmic accumulation of beta-catenin was observed in 3 (75%) of 4 cell lines and 18 (90%) of 20 cancer tissue samples. The Axin1 gene may be one of the mutational target in oral SCC. In addition, the cytoplasmic accumulation of beta-catenin is a common characteristic of oral SCC, but is not closely associated with mutational alterations in the APC, beta-catenin and Axin1 genes. Show less