Bilateral Knee Osteoarthritis Treated With Medial Open-Wedge High Tibial Osteotomy Using Two Types of ß-Tricalcium Phosphate With Differing Placements in Each Knee: A Report of Two Cases.

In medial open-wedge high tibial osteotomy (MOWHTO) for knee osteoarthritis, synthetic bone is commonly used as a replacement material for the opening gap. Unidirectional porous ß-tricalcium phosphate (UDPTCP) and spherical porous ß-tricalcium phosphate (SPTCP) have been widely used in this regard. In general, the two prostheses are placed parallel to the osteotomy opening gap. In this report, we discuss two cases involving a 63-year-old woman and a 51-year-old man who underwent MOWHTO for bilateral knee osteoarthritis. Both patients had experienced bilateral knee pain. In both patients, UDPTCP was placed anteriorly and SPTCP was placed posteriorly in one knee, with the placement reversed in the other knee. The remodeling of each type of ß-TCP was evaluated using CT immediately after the surgery and one year postoperatively. The postoperative corrective loss and clinical outcomes were also evaluated. Remodeling with ß-TCP was found to be faster with UDPTCP than with SPTCP, even though the anteroposterior placement differed laterally in each patient. Furthermore, there was no correction loss, and the clinical outcomes were comparable, regardless of the placement of ß-TCP.

Gene array analysis of neural crest cells identifies transcription factors necessary for direct conversion of embryonic fibroblasts into neural crest cells.

Neural crest cells (NC cells) are multipotent cells that emerge from the edge of the neural folds and migrate throughout the developing embryo. Although the gene regulatory network for generation of NC cells has been elucidated in detail, it has not been revealed which of the factors in the network are pivotal to directing NC identity. In this study we analyzed the gene expression profile of a pure NC subpopulation isolated from Sox10-IRES-Venus mice and investigated whether these genes played a key role in the direct conversion of Sox10-IRES-Venus mouse embryonic fibroblasts (MEFs) into NC cells. The comparative molecular profiles of NC cells and neural tube cells in 9.5-day embryos revealed genes including transcription factors selectively expressed in developing trunk NC cells. Among 25 NC cell-specific transcription factor genes tested, SOX10 and SOX9 were capable of converting MEFs into SOX10-positive (SOX10+) cells. The SOX10+ cells were then shown to differentiate into neurons, glial cells, smooth muscle cells, adipocytes and osteoblasts. These SOX10+ cells also showed limited self-renewal ability, suggesting that SOX10 and SOX9 directly converted MEFs into NC cells. Conversely, the remaining transcription factors, including well-known NC cell specifiers, were unable to convert MEFs into SOX10+ NC cells. These results suggest that SOX10 and SOX9 are the key factors necessary for the direct conversion of MEFs into NC cells.

Enhanced expression of retinoic acid receptor alpha (RARA) induces epithelial-to-mesenchymal transition and disruption of mammary acinar structures.

The early steps of mammary tumorigenesis include loss of epithelial cell polarity, escape from anoikis, and acquisition of proliferative capacity. The genes responsible for these processes are predicted to be early diagnostic markers or new therapeutic targets. Here we tested 51 genes coamplified with ERBB2 in the 17q12-21 amplicon for these tumorigenic activities using an MCF10A 3D culture-based screening system. We found that overexpression of retinoic acid receptor α (RARA) disrupted normal acinar structure and induced epithelial-to-mesenchymal transition (EMT). The mRNA levels of known EMT-inducing factors, including SLUG, FOXC2, ZEB1, and ZEB2, were significantly increased upon RARA overexpression. Knockdown of ZEB1 suppressed the RARA-mediated EMT phenotype. These results suggest that overexpression of RARA enhances malignant transformation during mammary tumorigenesis.

Expression screening of 17q12-21 amplicon reveals GRB7 as an ERBB2-dependent oncogene.

Gene amplification is a major genetic alteration in human cancers. Amplicons, amplified genomic regions, are believed to contain "driver" genes responsible for tumorigenesis. However, the significance of co-amplified genes has not been extensively studied. We have established an integrated analysis system of amplicons using retrovirus-mediated gene transfer coupled with a human full-length cDNA set. Applying this system to 17q12-21 amplicon observed in breast cancer, we identified GRB7 as a context-dependent oncogene, which modulates the ERBB2 signaling pathway through enhanced phosphorylation of ERBB2 and Akt. Our work provides an insight into the biological significance of gene amplification in human cancers.

Genome-wide identification of endothelial cell-enriched genes in the mouse embryo.

The early blood vessels of the embryo and yolk sac in mammals develop by aggregation of de novo-forming angioblasts into a primitive vascular plexus, which then undergoes a complex remodeling process. Angiogenesis is also important for disease progression in the adult. However, the precise molecular mechanism of vascular development remains unclear. It is therefore of great interest to determine which genes are specifically expressed in developing endothelial cells (ECs). Here, we used Flk1-deficient mouse embryos, which lack ECs, to perform a genome-wide survey for genes related to vascular development. We identified 184 genes that are highly enriched in developing ECs. The human orthologs of most of these genes were also expressed in HUVECs, and small interfering RNA knockdown experiments on 22 human orthologs showed that 6 of these genes play a role in tube formation by HUVECs. In addition, we created Arhgef15 knockout and RhoJ knockout mice by a gene-targeting method and found that Arhgef15 and RhoJ were important for neonatal retinal vascularization. Thus, the genes identified in our survey show high expression in ECs; further analysis of these genes should facilitate our understanding of the molecular mechanisms of vascular development in the mouse.

Direct reprogramming of somatic cells is promoted by maternal transcription factor Glis1.

Induced pluripotent stem cells (iPSCs) are generated from somatic cells by the transgenic expression of three transcription factors collectively called OSK: Oct3/4 (also called Pou5f1), Sox2 and Klf4. However, the conversion to iPSCs is inefficient. The proto-oncogene Myc enhances the efficiency of iPSC generation by OSK but it also increases the tumorigenicity of the resulting iPSCs. Here we show that the Gli-like transcription factor Glis1 (Glis family zinc finger 1) markedly enhances the generation of iPSCs from both mouse and human fibroblasts when it is expressed together with OSK. Mouse iPSCs generated using this combination of transcription factors can form germline-competent chimaeras. Glis1 is enriched in unfertilized oocytes and in embryos at the one-cell stage. DNA microarray analyses show that Glis1 promotes multiple pro-reprogramming pathways, including Myc, Nanog, Lin28, Wnt, Essrb and the mesenchymal-epithelial transition. These results therefore show that Glis1 effectively promotes the direct reprogramming of somatic cells during iPSC generation.

Naringenin and hesperetin induce growth arrest, apoptosis, and cytoplasmic fat deposit in human preadipocytes.

Citrus flavonoids are reported to be promising bioactive compounds against hyperlipidemia and lipid biosynthesis. However, the mechanism of the lipid lowering effect by flavonoids remains unknown. The present study examines the effect of some flavanones on the adipocytic conversion of the human preadipocyte cell line, AML-I. Among four structure-related flavanones including naringenin, naringenin-7-rhamnoglucoside (naringin), hesperetin, and hesperetin-7-rhamnoglucoside (hesperidin), the aglycones such as naringenin and hesperetin exhibited the growth arrest of AML-I cells. When the cells were examined by Annexin V-FITC staining method, it was noticed that growth arrest was induced by apoptotic cell death. In the study of apoptosis-related protein in the naringenin-treated cells, anti-apoptotic proteins such as p-Akt, NF-kappaB, and Bcl-2 were decreased, and pro-apoptotic protein Bad was accumulated by Western blot analysis. Interestingly, exposure of AML-I cells to naringenin or hesperetin during short-term cultures increased cytoplasmic lipid droplets by Sudan Black B staining. Furthermore, expression of fatty acid synthase (FAS) and peroxisome proliferator activated receptor (PPAR)-gamma was enhanced in naringenin-treated cells. These data suggest that apoptosis by flavanones does not inhibit the adipocytic conversion of AML-I preadipocytes. The result also indicates that adipocyte may not be a direct target for the lipid-lowering activity of the flavanones.