👤 Tamotsu Kuroki

Congenital hypogonadotropic hypogonadism (CHH) is a rare endocrine disorder characterized by gonadal dysfunction attributed to impaired gonadotropin secretion. CHH is associated with approximately 60 genes including Show less

Ovarian cancer is the leading cause of gynecologic cancer-related deaths. The propensity for metastasis within the peritoneal cavity is a driving factor for the poor outcomes associated with this disease, but there is currently no effective therapy targeting metastasis. In this study, we investigate the contribution of stromal cells to ovarian cancer metastasis and identify normal stromal cell expression of the collagen receptor, discoidin domain receptor 2 (DDR2), that acts to facilitate ovarian cancer metastasis. In vivo, global genetic inactivation of Ddr2 impairs the ability of Ddr2-expressing syngeneic ovarian cancer cells to spread throughout the peritoneal cavity. Specifically, DDR2 expression in mesothelial cells lining the peritoneal cavity facilitates tumor cell attachment and clearance. Subsequently, omentum fibroblast expression of DDR2 promotes tumor cell invasion. Mechanistically, we find DDR2-expressing fibroblasts are more energetically active, such that DDR2 regulates glycolysis through AKT/SNAI1 leading to suppressed fructose-1,6-bisphosphatase and increased hexokinase activity, a key glycolytic enzyme. Upon inhibition of DDR2, we find decreased protein synthesis and secretion. Consequently, when DDR2 is inhibited, there is reduction in secreted extracellular matrix proteins important for metastasis. Specifically, we find that fibroblast DDR2 inhibition leads to decreased secretion of the collagen crosslinker, LOXL2. Adding back LOXL2 to DDR2 deficient fibroblasts rescues the ability of tumor cells to invade. Overall, our results suggest that stromal cell expression of DDR2 is an important mediator of ovarian cancer metastasis. DDR2 is highly expressed by stromal cells in ovarian cancer that can mediate metastasis and is a potential therapeutic target in ovarian cancer. Show less

Subcutaneous transplantation of engineered hepatocyte/fibroblast sheets (EHFSs) is a low invasive and safe approach to construct vascularized subcutaneous human liver tissue (VSLT). However, the liver-specific structures and functionalities in the development process of VSLTs in mice remain poorly understood. Here, we describe time-dependent characteristics of the formation of the vascular network, cell-cell adhesions, liver transporters, liver-specific protein synthesis, and metabolizing activities. The EHFSs formed multilayered thick tissues by rapid neovascularization, which allows overcoming extremely difficult problems, such as the lack of oxygen supply on the formation of three-dimensional primary hepatocyte tissue under the skin. The blood vessels consisted of mouse-origin endothelial cells (ECs) (mVEGFR2) from the subcutaneous space at 1-7 days, and the following formation of the vascular network was performed by human-origin ECs (hVEGFR2). Many varieties of liver-specific gene expressions increased with the construction of the VSLTs: cell-cell adhesion molecules (CDH1, CLDN3, and CX32), transporters at basal (OATP1A1, OCT1, and NTCP) and apical membranes (MRP2, MDR1, and BSEP), blood coagulation factors (F8 and F9), urea synthesis (CPS1, OTC, and ARG1), and metabolism enzymes (CYP7A1, CYP1A2, CYP2B6, CYP3A4, and UGT1A1). Subacute hepatic failure model mice with VSLT were alive at least 7 weeks after liver damage. Thus, the ectopic liver organ offers the potential for a low invasive and safe treatment for liver diseases. Show less

JmjC domain-containing proteins are a class of enzymes responsible for histone demethylation. Previous studies revealed that the JmjC domain-containing protein KDM3A possesses intrinsic demethylase activity toward lysine 9 of histone H3 and plays essential roles in spermiogenesis. In contrast, the biological roles of JMJD1C, a KDM3A homolog in mice, are largely unknown. Here we present the crucial role of JMJD1C in male gametogenesis. Jmjd1c-deficient males became infertile due to the progressive reduction of germ cells after 3 mo of age. Importantly, Jmjd1c-deficient testes frequently contained abnormal tubules lacking developmentally immature germ cells. JMJD1C is most abundantly expressed in undifferentiated spermatogonia in mouse testis. The numbers of ZBTB16-positive spermatogonia and apoptotic germ cells in Jmjd1c-deficient testes decreased and increased in an age-dependent manner, respectively. Our studies demonstrated that JMJD1C contributes to the long-term maintenance of the male germ line. Show less