Takafumi Ichikawa

• PhD
• Professor (Assistant) at Kyoto University

Non-human primates, such as cynomolgus monkeys, are invaluable experimental models for understanding human biology and disease. Their close genetic relationship to humans makes them essential for studying fundamental human developmental processes and disease progression. Although lentiviral methods for generating transgenic monkeys exist, several i...

Tissue patterning coordinates morphogenesis, cell dynamics and fate specification. Understanding how precision in patterning is robustly achieved despite inherent developmental variability during mammalian embryogenesis remains a challenge. Here, based on cell dynamics quantification and simulation, we show how salt-and-pepper epiblast and primitiv...

How living systems achieve precision in form and function despite their intrinsic stochasticity is a fundamental yet ongoing question in biology. We generated morphomaps of preimplantation embryogenesis in mouse, rabbit, and monkey embryos, and these morphomaps revealed that although blastomere divisions desynchronized passively, 8-cell embryos con...

Topological defects determine the collective properties of anisotropic materials. How their configurations are controlled is not well understood however, especially in 3D. In living matter moreover, 2D defects have been linked to biological functions, but the role of 3D polar defects is unclear. Combining computational and experimental approaches,...

Cellular functions, such as differentiation and migration, are regulated by the extracellular microenvironment, including the extracellular matrix (ECM). Cells adhere to ECM through focal adhesions (FAs) and sense the surrounding microenvironments. While FA proteins have been actively investigated, little is known about the lipids in the plasma mem...

Tissue patterning coordinates morphogenesis, cell dynamics and fate specification. Understanding how these processes are coupled to achieve precision despite their inherent variability remains a challenge. Here, we investigate how salt-and-pepper epiblast and primitive endoderm (PrE) cells sort and robustly pattern the inner cell mass (ICM) of mamm...

How living systems achieve precision in form and function despite their intrinsic stochasticity is a fundamental yet open question in biology. Here, we establish a quantitative morphomap of pre-implantation embryogenesis in mouse, rabbit and monkey embryos, which reveals that although blastomere divisions desynchronise passively without compensatio...

In this selection, we celebrate the art of science by highlighting some of the submitted cover images from the past year. In this collection, our authors share the stories behind their inspiration for how to portray their science to captivate a broader audience.

Upon implantation, mammalian embryos undergo major morphogenesis and key developmental processes such as body axis specification and gastrulation. However, limited accessibility obscures the study of these crucial processes. Here, we develop an ex vivo Matrigel-collagen-based culture to recapitulate mouse development from E4.5 to E6.0. Our system n...

Upon implantation, mammalian embryos undergo major morphogenesis and key developmental processes such as body axis specification and gastrulation. However, limited accessibility obscures study of these crucial processes. Here, we develop an ex vivo Matrigel-collagen-based culture to recapitulate mouse development from E4.5 to 6.0. Our system not on...

P-glycoprotein (P-gp; also known as MDR1 or ABCB1) is an ATP-driven multidrug transporter that extrudes various hydrophobic toxic compounds to the extracellular space. P-gp consists of two transmembrane domains (TMDs) that form the substrate translocation pathway and two nucleotide-binding domains (NBDs) that bind and hydrolyze ATP. At least two P-...

P-glycoprotein (P-gp; also known as MDR1 or ABCB1) is an ATP-driven multidrug transporter that extrudes various hydrophobic toxic compounds to the extracellular space. P-gp consists of two transmembrane domains (TMDs) that form the substrate translocation pathway and two nucleotide-binding domains (NBDs) that bind and hydrolyze ATP. P-gp takes at l...

Extracellular matrix (ECM) stiffness regulates various cell behaviors, including cell differentiation, proliferation and migration. Vinculin and vinexin α (an isoform encoded by the SORBS3 gene), both of which localize to focal adhesions, cooperatively function as mechanosensors of ECM stiffness. On a rigid ECM, vinexin α interacts with vinculin an...

Vinexin, CAP and ArgBP2 constitute an adaptor protein family called the vinexin (SORBS) family that is targeted to focal adhesions (FAs). Although numerous studies have focused on each of the SORBS proteins and partially elucidated their involvement in mechanotransduction, a comparative analysis of their function has not been well addressed. Here,...

Recent progress in understanding the essential roles of mechanical forces in regulating various cellular processes expands the field of biology to one where interdisciplinary approaches with engineering techniques become indispensable. Contractile forces or contractility-inherently present in proliferative cells due to the activity of ubiquitous no...

The extracellular matrix (ECM) is a major regulator of cell behavior. Recent studies have indicated the importance of the physical properties of the ECM, including its stiffness, for cell migration and differentiation. Using actomyosin-generated forces, cells pull the ECM and sense stiffness via cell-ECM adhesion structures called focal adhesions (...

The number of FAs and the total integrated density of vinculin immunostaining without CSB treatment. GFP-vinculin-expressing cells cultured on polyacrylamide gels (A-C) or on coverslips (D-F) were fixed without CSB treatment and visualized using GFP. Fifty individual cells from three separate experiments (A) or thirty individual cells from two sepa...

Total integrated density of CSB-resistant vinculin mutants quantified from Fig 4A using ImageJ. The values represent the means ± S.E.M. Bonferroni’s test (n = 30; **P<0.01; n.s., non-significant). (PDF)

Analysis of T12/IA and T12/VA vinculin mutants. (A) FRAP analysis of T12/IA and T12/VA mutants on polyacrylamide gels. GFP-T12/IA- or GFP-T12/VA-expressing vinculin KD cells were cultured on soft (3.8 kPa) or rigid gel (25 kPa) substrates. FRAP analysis was performed and normalized fluorescence recovery of EGFP-vinculin was plotted using data from...

Total integrated density of the CSB-resistant vinculin mutants, quantified from Fig 3A using ImageJ. The values represent the means ± S.E.M. One-way ANOVA, Scheffe’s test (n = 50; *P<0.05, **P<0.01, ***P<0.001; n.s., non-significant). (PDF)

Although extracellular matrix (ECM) stiffness is an important factor of the extracellular microenvironment and is known to direct the lineage specification of stem cells and affect cancer progression, the molecular mechanisms that sense ECM stiffness have not yet been elucidated. In this study, we show that the proline-rich linker (PRL) region of v...

Discs large homolog 5 (Dlg5) is a member of the membrane-associated guanylate kinase adaptor family of proteins, some of which are involved in the regulation of epithelial-to-mesenchymal transition (EMT). Dlg5 has been described as a susceptibility gene for Crohn's disease; however, the physiological function of Dlg5 is unknown. We show here that t...

The expression of Dlg5 and vinexin α/β after TGF-β stimulation. A: LLc-PK1 cells were incubated with 4 ng/ml of TGF-β for two days. Total RNA was isolated from the cells and Dlg5 mRNA was quantitated by real-time PCR. The values represent the mean ± S.E. of relative mRNA amounts from three independent experiments. B: LLc-PK1 cells were incubated wi...

Effect of siDlg5#2 on expression of SMA and fibronectin. LLc-PK1 cells were treated with 4 ng/ml TGF-β or transfected with control siRNA or Dlg5 siRNA (#1, #2) followed by incubation for three days. Cells were lysed and protein expression detected by immunoblotting using the indicated antibodies. β-tubulin expression was examined as a loading contr...

Effect of depletion of Dlg5 expression in PC3 cells. shRNA plasmid for Dlg5 or control plasmid were introduced into PC3 cells using lentivirus. Transfected cells were selected by the incubation with 1.0 µg/ml puromycin. Lysates were prepared from cells stably transfected with shRNA for Dlg5 or control plasmid. The cell lysates were immunoblotted us...

Snail mRNA in TGF-β treated and Dlg5-knockdown cells. LLc-PK1 cells were transfected with control siRNA or Dlg5 siRNA#1 (A) or treated with 4 ng/ml TGF-β (B). After two days of incubation, total RNA was isolated from the cells and Snail mRNA was quantitated by real-time PCR. The values represent the mean ± S.E. of relative mRNA amounts from three i...

E-cadherin mRNA in Dlg5-knockdown cells. Control siRNA (GFP siRNA or control siRNA1 (unrelated)) or Dlg5 siRNA (#1 or #2) was transfected into LLc-PK1 cells. Two days after transfection, total RNA was isolated from the cells and E-cadherin mRNA was quantitated by real-time PCR. The values represent the mean ± S.E. of relative mRNA amounts from thre...

Effect of β-catenin knockdown. Dlg5 siRNA and β-catenin siRNA were transfected into LLc-PK1 cells with or without stimulation with 4 ng/ml TGF-β. After three days of incubation, cells were lysed and protein expression detected by immunoblotting using the indicated antibodies. (TIF)