Masashi Nomi

Mouse Ror2 receptor tyrosine kinase is required for the heart development and limb formation

A mouse receptor tyrosine kinase (RTK), mRor2, which belongs to the Ror‐family of RTKs consisting of at least two structurally related members, is primarily expressed in the heart and nervous system during mouse development. To elucidate the function of mRor2, we generated mice with a mutated mRor2 locus.

Expression of the receptor tyrosine kinase genes, Ror1 and Ror2, during mouse development.

In mammals, the Ror-family receptor tyrosine kinases consist of two structurally related proteins, Ror1 and Ror2, characterized by the extracellular Frizzled-like cysteine-rich domain and membrane proximal kringle domains. As an attempt to gain insights into their roles in mouse development, expression patterns of Ror1 and Ror2 during early embryogenesis were examined and compared. Interestingly, at early stages, Ror1 and Ror2 exhibit similar expression patterns in the developing face, including the frontonasal process and pharyngeal arches, which are derived from cephalic neural crest cells. On the other hand, they exhibit different expression patterns in the developing limbs and brain, where the expression of Ror2 was detected broadly compared with that of Ror1. At a later stage, both genes are expressed in a similar fashion in the developing heart and lung, yet in a distinct manner in the brain and eye.

Loss of mRor1 Enhances the Heart and Skeletal Abnormalities in mRor2-Deficient Mice: Redundant and Pleiotropic Functions of mRor1 and mRor2 Receptor Tyrosine Kinases

ABSTRACT The mammalian Ror family of receptor tyrosine kinases consists of two structurally related proteins, Ror1 and Ror2. We have shown that mRor2-deficient mice exhibit widespread skeletal abnormalities, ventricular septal defects in the heart, and respiratory dysfunction, leading to neonatal lethality (S. Takeuchi, K. Takeda, I. Oishi, M. Nomi, M. Ikeya, K. Itoh, S. Tamura, T. Ueda, T. Hatta, H. Otani, T. Terashima, S. Takada, H. Yamamura, S. Akira, and Y. Minami, Genes Cells 5:71–78, 2000). Here we show thatmRor1-deficient mice have no apparent skeletal or cardiac abnormalities, yet they also die soon after birth due to respiratory dysfunction. Interestingly,mRor1/mRor2 double mutant mice show markedly enhanced skeletal abnormalities compared withmRor2 mutant mice. Furthermore, double mutant mice also exhibit defects not observed in mRor2 mutant mice, including a sternal defect, dysplasia of the symphysis of the pubic bone, and complete transposition of the great arteries. These results indicate that mRor1 and mRor2 interact genetically in skeletal and cardiac development.

Intercellular Adhesion Molecule 1 Discriminates Functionally Different Populations of Human Osteoblasts: Characteristic Involvement of Cell Cycle Regulators

The concept of differential regulation of certain adhesion molecules on different cell subsets and their relevance to cell functions has emerged in recent years. The initial event in bone remodeling is an increase in osteoclastic bone resorption and cell adhesion between osteoclastic precursors and bone marrow stromal cells or osteoblasts is known to commit the osteoclast development. Here, we show that human osteoblasts can be divided into two subsets based on the expression of the intercellular adhesion molecule (ICAM)‐1; ICAM‐1+ osteoblasts highly adhered to monocytes, including osteoclast precursors, produced osteoclast differentiation factor (ODF), and induced multinuclear osteoclast‐like cell formation. Anti‐ODF monoclonal antibody (mAb) did not inhibit the adhesion of monocytes to osteoblastic cells, whereas anti‐leukocyte function‐associated antigen (LFA)‐1, a receptor for ICAM‐1, mAb blocked the adhesion. We thereby propose that the higher affinity adhesion via LFA‐1/ICAM‐1 is prerequisite for efficient function of membrane‐bound ODF during osteoclast maturation. The functional characteristics of ICAM‐1+ osteoblasts were emphasized further by cell cycle regulation, as manifested by (i) up‐regulation of p53 and p21, (ii) reduction of activity of cyclin‐dependent kinase (cdk) 6, (iii) underphosphorylation of retinoblastoma protein, (iv) increased Fas but reduced bcl‐2 expression, and (v) majority of cells remained at G0/G1 phase. Furthermore, ICAM‐1+ osteoblasts were induced by interleukin‐1β (IL‐1β). Taken together, we propose that the differentiation of osteoblasts to ICAM‐1+ subpopulation by inflammatory cytokines plays an important role in osteoporosis, which is observed in patients with chronic inflammation, because ICAM‐1+ osteoblasts can bias bone turnover to bone resorption, committing osteoclast maturation through cell adhesion with its precursor, and the majority of ICAM‐1+ osteoblasts arrested at G0/G1 phase. Such regulation of cell cycle arrest also is an important determinant of the life span of cells in bone in which continuous bone remodeling maintains its homeostasis.

Role of Growth Factors and Endothelial Cells in Therapeutic Angiogenesis and Tissue Engineering

To achieve the goals of engineering large complex tissues, and possibly internal organs, vascularization of the regenerating tissue is essential. To maintain the initial volume after implantation of regenerated tissue, improved vascularization is considered to be important. Recent advances in understanding the process of blood vessel growth has offered significant tools for the neovascularization of bioengineered tissues and therapeutic angiogenesis. Several angiogenic growth factors including vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and hepatocyte growth factor (HGF) were used for vascularization of ischemic tissues. Other approaches such as prevascularization of the scaffold, prior to cell seeding, and incorporation of endothelial cells in the bioengineered tissue showed encouraging results. In this article, we will review recent advances in angiogenic growth factors, and discuss the role of these growth factors and endothelial cells in therapeutic angiogenesis and tissue engineering.

Independent Prognostic Value of Serum Hepatocyte Growth Factor in Bladder Cancer

PURPOSE We retrospectively investigated whether the level of serum hepatocyte growth factor could predict the prognosis and extent of transitional-cell carcinoma of the urinary bladder. PATIENTS AND METHODS Serum samples were collected from 113 patients with bladder cancer and from 200 healthy controls. Of the 113 patients, 59 had superficial bladder cancer and 54 had muscle-invasive cancer. Thirteen bladder cancer tissues (eight superficial and five muscle-invasive) were also collected. The levels of hepatocyte growth factor in the serum and tissues of these individuals were measured by enzyme-linked immunoadsorbent assay using hepatocyte growth factor antibodies. RESULTS The levels of hepatocyte growth factor in the serum and tissues of patients with muscle-invasive cancer were significantly higher than those of patients with superficial bladder cancer (P <.0001 and P =.0054, respectively). The degree of elevation above the normal level of serum hepatocyte growth factor of the former (61.1%) was significantly higher than that of the latter (8.4%; P <.0001). The elevation was highest in patients with visceral metastasis (93.3%). Among patients with superficial bladder cancer, the overall survival rate of those with low levels of serum hepatocyte growth factor was significantly greater than that of those with high levels (P =.005). Among patients with minimally invasive bladder cancer, the disease-free and overall survival rates of those with high levels of serum hepatocyte growth factor were significantly lower than the same rates of those with low levels (P <.001 and P =.0028, respectively). CONCLUSION Our study suggests that the level of hepatocyte growth factor in serum could be a predictor of patient survival and extent of bladder cancer.

Conservative therapy for stage T1b, grade 3 transitional cell carcinoma of the bladder

OBJECTIVES To retrospectively evaluate the usefulness of transurethral resection of bladder tumor (TURBT) and intravesical instillation for pT1bG3 transitional cell carcinoma of the urinary bladder. METHODS Between May 1984 and May 1997, 45 patients with pT1bG3 transitional cell carcinoma of the urinary bladder underwent TURBT and intravesical instillation with bacillus Calmette-Guerin (BCG) or other anticancer agents. Random biopsy was carried out in 37 patients. The recurrence-free survival rate was determined by tumor size, number of tumors, lymphovascular invasion, and drugs used for intravesical instillation. The median follow-up period was 63 months (range 4 to 145) after the initial TURBT. RESULTS Of 37 patients who underwent random biopsy, concomitant carcinoma in situ was detected in 18 patients (48.6%). The incidence of concomitant CIS was significantly higher in patients with multiple tumors (P = 0.029). Vesical recurrence was noted in 16 patients (35.6%). The overall 1-, 3-, and 5-year recurrence-free survival rates were 88.5%, 66.7%, and 66.7%, respectively. Progression (muscular invasion) occurred in only 2 patients (4.4%). Total cystectomy was performed in 4 patients, including the 2 patients with progressive disease, and 2 patients with recurrent CIS that resisted BCG therapy. None of the patients died of bladder cancer. CONCLUSIONS Our results suggest that aggressive attempts at initial or subsequent TURBT combined with BCG therapy achieved good control of pT1bG3 transitional cell carcinoma of the urinary bladder.

Detection of prostate carcinoma using prostate specific antigen, its density, and the density of the transition zone in Japanese men with intermediate serum prostate specific antigen concentrations.

This study was undertaken to determine whether the prostate specific antigen (PSA) density (PSAD) and PSAD of the transition zone (PSADT) are useful in the detection of prostate carcinoma in Japanese men with intermediate levels of serum PSA.

Modulation of the microenvironment by growth factors regulates the in vivo growth of skeletal myoblasts.

To investigate the optimal microenvironment for efficient myoblast transplantation in vivo.

Predicting the extent of prostate cancer using the combination of systematic biopsy and serum prostate‐specific antigen in Japanese men

To determine the utility of systematic biopsy alone or combined with an assay of serum prostate‐specific antigen (PSA) level to predict the extent of prostate cancer in Japanese men.