Stiffness of primordial germ cells is required for their extravasation in avian embryos

細胞の血行性転移の新たな仕組みを発見 --世界初、新たながん転移抑止戦略の開発にも期待--. 京都大学プレスリリース. 2022-12-13.Unlike mammals, primordial germ cells (PGCs) in avian early embryos exploit blood circulation to translocate to the somatic gonadal primordium, but how circulating PGCs undergo extravasation remains elusive. We demonstrate with single-cell level live-imaging analyses that the PGCs are arrested at a specific site in the capillary plexus, which is predominantly governed by occlusion at a narrow path in the vasculature. The occlusion is enabled by a heightened stiffness of the PGCs mediated by actin polymerization. Following the occlusion, PGCs reset their stiffness to soften in order to squeeze through the endothelial lining as they transmigrate. Our discovery also provides a model for the understanding of metastasizing cancer extravasation occurring mainly by occlusion

The association of C-reactive protein with an oxidative metabolite of LDL and its implication in atherosclerosis

C-reactive protein (CRP) is one of the strongest independent predictors of cardiovascular disease. We have previously reported that oxidized LDL (oxLDL) interacts with beta 2-glycoprotein I (beta 2GPI), implicating oxLDL/P2GPI complexes as putative autoantigens in autoimmune-mediated atherosclerotic vascular disease. In this study, we investigated the interaction of CRP with oxLDL/beta 2GPI complexes and its association with atherosclerosis in patients with diabetes mellitus (DM). CRP/oxLDL/R2GPI complexes were predominantly found in sera of DM patients with atherosclerosis. In contrast, noncomplexed CRP isoforms were present in sera of patients with acute/chronic inflammation, i.e., various pyrogenic diseases, rheumatoid arthritis (RA), and DM. Immunohistochemistry staining colocalized CRP and beta 2GPI together with oxLDL in carotid artery plaques but not in synovial tissue from RA patients, strongly suggesting that complex formation occurs during the development of adierosclerosis. Serum levels of CRP correlated with soluble forms of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1, and oxLDL/beta 2GPI complexes correlated with total cholesterol and hemoglobin Al c. Thus, the generation of CRP/oxLDL/beta 2GPI complexes seems to be associated with arterial inflammation, hyperglycemia, and hypercholesterolemia. CRP/oxLDL/R2GPI complexes can be distinguished from pyrogenic noncomplexed CRP isoforms and may represent a more specific and predictive marker for atherosclerosis

Characterization and Scaled-Up Production of Azido-Functionalized Silk Fiber Produced by Transgenic Silkworms with an Expanded Genetic Code

The creation of functional materials from renewable resources has attracted much interest. We previously reported on the genetic code expansion of the domesticated silkworm Bombyx mori to functionalize silk fiber with synthetic amino acids such as 4-azido-L-phenylalanine (AzPhe). The azido groups act as selective handles for biorthogonal chemical reactions. Here we report the characterization and scaled-up production of azido-functionalized silk fiber for textile, healthcare, and medical applications. To increase the productivity of azido-functionalized silk fiber, the original transgenic line was hybridized with a high silk-producing strain. The F1 hybrid produced circa 1.5 times more silk fibroin than the original transgenic line. The incorporation efficiency of AzPhe into silk fibroin was retained after hybridization. The tensile properties of the azido-functionalized silk fiber were equal to those of normal silk fiber. Scaled-up production of the azido-functionalized silk fiber was demonstrated by rearing circa 1000 transgenic silkworms. Differently-colored fluorescent silk fibers were successfully prepared by click chemistry reactions, demonstrating the utility of the azido-functionalized silk fiber for developing silk-based materials with desired functions

Generation of hybrid hepatocytes by cell fusion from monkey embryoid body cells in the injured mouse liver

Monkey embryonic stem (ES) cells have characteristics that are similar to human ES cells, and might be useful as a substitute model for preclinical research. When embryoid bodies (EBs) formed from monkey ES cells were cultured, expression of many hepatocyte-related genes including cytochrome P450 (Cyp) 3a and Cyp7a1 was observed. Hepatocytes were immunocytochemically observed using antibodies against albumin (ALB), cytokeratin-8/18, and α1-antitrypsin in the developing EBs. The in vitro differentiation potential of monkey ES cells into the hepatic lineage prompted us to examine the transplantabilityof monkey EB cells. As an initial approach to assess the repopulation potential, we transplanted EB cells into immunodeficient urokinase-type plasminogen activator transgenic mice that undergo liver failure. After transplantation, the hepatocyte colonies expressing monkey ALB were observed in the mouse liver. Fluorescence in-situ hybridization revealed that the repopulating hepatocytes arise from cell fusion between transplanted monkey EB cells and recipient mouse hepatocytes. In contrast, neither cell fusion nor repopulation of hepatocytes was observed in the recipient liver after undifferentiated ES cell transplantation. These results indicate that the differentiated cells in developing monkey EBs, but not contaminating ES cells, generate functional hepatocytes by cell fusion with recipient mouse hepatocytes, and repopulate injured mouse liver