Tohru Morisada

Angiogenic Role of LYVE-1–Positive Macrophages in Adipose Tissue

Here we report the discovery of a characteristic dense vascular network (DVN) in the tip portion of epididymal adipose tissue in adult mice. The DVN is formed by angiogenesis rather than by vasculogenesis, and has functional blood circulation. This DVN and its subsequent branching may provide a new functional route for adipogenesis. The recruitment, infiltration, and accumulation of bone marrow-derived LYVE-1+ macrophages in the tip region are crucial for the formation of the DVN. Matrix metalloproteinases (MMPs) and the VEGF-VEGFR2 system are responsible not only for the formation of the DVN, but also for the recruitment and infiltration of LYVE-1+ macrophages into the epididymal adipose tissue tip region. SDF-1, but not the MCP-1-CCR2 system, is a critical factor in recruitment and ongoing retention of macrophages in this area. We also demonstrate that the tip region of epididymal adipose tissue is highly hypoxic, and thus provides a microenvironment conducive to the high expression and enhanced activities of VEGF, VEGFR2, MMPs, and SDF-1 in autocrine and paracrine manners, to create an ideal niche for the recruitment, retention, and angiogenic action of macrophages. These findings shed light on the complex interplay between macrophage infiltration, angiogenesis, and adipogenesis in the tip region of adult epididymal adipose tissue, and provide novel insight into the regulation of alternative outgrowth of adipose tissue.

Angiopoietin-related growth factor antagonizes obesity and insulin resistance

Angiopoietin-related growth factor (AGF), a member of the angiopoietin-like protein (Angptl) family, is secreted predominantly from the liver into the systemic circulation. Here, we show that most (>80%) of the AGF-deficient mice die at about embryonic day 13, whereas the surviving AGF-deficient mice develop marked obesity, lipid accumulation in skeletal muscle and liver, and insulin resistance accompanied by reduced energy expenditure relative to controls. In parallel, mice with targeted activation of AGF show leanness and increased insulin sensitivity resulting from increased energy expenditure. They are also protected from high-fat diet–induced obesity, insulin resistance and nonadipose tissue steatosis. Hepatic overexpression of AGF by adenoviral transduction, which leads to an approximately 2.5-fold increase in serum AGF concentrations, results in a significant (P < 0.01) body weight loss and increases insulin sensitivity in mice fed a high-fat diet. This study establishes AGF as a new hepatocyte-derived circulating factor that counteracts obesity and related insulin resistance.

Spreds Are Essential for Embryonic Lymphangiogenesis by Regulating Vascular Endothelial Growth Factor Receptor 3 Signaling

ABSTRACT Spred/Sprouty family proteins negatively regulate growth factor-induced ERK activation. Although the individual physiological roles of Spred-1 and Spred-2 have been investigated using gene-disrupted mice, the overlapping functions of Spred-1 and Spred-2 have not been clarified. Here, we demonstrate that the deletion of both Spred-1 and Spred-2 resulted in embryonic lethality at embryonic days 12.5 to 15.5 with marked subcutaneous hemorrhage, edema, and dilated lymphatic vessels filled with erythrocytes. This phenotype resembled that of Syk−/− and SLP-76−/− mice with defects in the separation of lymphatic vessels from blood vessels. The number of LYVE-1-positive lymphatic vessels and lymphatic endothelial cells increased markedly in Spred-1/2-deficient embryos compared with WT embryos, while the number of blood vessels was not different. Ex vivo colony assay revealed that Spred-1/2 suppressed lymphatic endothelial cell proliferation and/or differentiation. In cultured cells, the overexpression of Spred-1 or Spred-2 strongly suppressed vascular endothelial growth factor-C (VEGF-C)/VEGF receptor (VEGFR)-3-mediated ERK activation, while Spred-1/2-deficient cells were extremely sensitive to VEGFR-3 signaling. These data suggest that Spreds play an important role in lymphatic vessel development by negatively regulating VEGF-C/VEGFR-3 signaling.

Angiopoietin-related growth factor (AGF) promotes epidermal proliferation, remodeling, and regeneration.

We report here the identification of an angiopoietin-related growth factor (AGF). To examine the biological function of AGF in vivo, we created transgenic mice expressing AGF in epidermal keratinocytes (K14-AGF). K14-AGF mice exhibited swollen and reddish ears, nose and eyelids. Histological analyses of K14-AGF mice revealed significantly thickened epidermis and a marked increase in proliferating epidermal cells as well as vascular cells in the skin compared with nontransgenic controls. In addition, we found rapid wound closure in the healing process and an unusual closure of holes punched in the ears of K14-AGF mice. Furthermore, we observed that AGF is expressed in platelets and mast cells, and detected at wounded skin, whereas there was no expression of AGF detected in normal skin tissues, suggesting that AGF derived from these infiltrated cells affects epidermal proliferation and thereby plays a role in the wound healing process. These findings demonstrate that biological functions of AGF in epidermal keratinocytes could lead to novel therapeutic strategies for wound care and epidermal regenerative medicine.

Angiopoietins and Angiopoietin-Like Proteins in Angiogenesis

Vascular network formation requires several endothelial cell growth factors. These factors have a potent angiogenic effect, and their precise coordination is essential for vascular development. Among them, angiopoietins function through the Tie2 receptor, whose signaling is critical to regulate vascular stabilization and remodeling. It has been reported that the angiopoietin/Tie2 signal is involved in survival and migration of endothelial cells and regulates vascular remodeling and maintenance of vascular integrity. More recent studies demonstrate that angiopoietin/Tie2 signaling is also required for lymphangiogenesis. The authors and several other groups have identified six angiopoietin-like proteins (Angptls) containing a coiled-coil domain and a fibrinogen-like domain, both of which are characteristic of angiopoietins. Interestingly, Angptls also function in angiogenesis through regulating survival and migration of endothelial cells, although Angptls do not bind the angiopoietin receptor Tie2. Currently, Angptls are orphan ligands, but they have been reported to have pleiotropic effects not only on vascular cells but also on metabolism and tumor biology. Here, the authors review current findings relating to the roles of angiopoietins and Angptls in vascular biology and discuss molecular mechanisms relevant to these factors and angiogenesis.

Angiopoietin-Related Growth Factor Enhances Blood Flow Via Activation of the ERK1/2-eNOS-NO Pathway in a Mouse Hind-Limb Ischemia Model

Objective—Transgenic mice overexpressing angiopoietin-related growth factor (AGF) exhibit enhanced angiogenesis, suggesting that AGF may be a useful drug target in ischemic disease. Our goal was to determine whether AGF enhances blood flow in a mouse hind-limb ischemia model and to define molecular mechanisms underlying AGF signaling in endothelial cells. Methods and Results—Intramuscular injection of adenovirus harboring AGF into the ischemic limb increased AGF production, which increased blood flow through induction of angiogenesis and arteriogenesis, thereby reducing the necessity for limb amputation. In vitro analysis showed that exposing human umbilical venous endothelial cells to AGF increased nitric oxide (NO) production through activation of an ERK1/2-endothelial NO synthetase (eNOS) signaling pathway. AGF-stimulated eNOS phosphorylation, NO production, and endothelial cell migration were all abolished by specific MEK1/2 inhibitors. Moreover, AGF did not restore blood flow to ischemic hind-limbs of either mice receiving NOS inhibitor L-NAME or eNOS knockout mice. Conclusion—Activation of an ERK1/2-eNOS-NO pathway is a crucial signaling mechanism by which AGF increases blood flow through induction of angiogenesis and arteriogenesis. Further investigation of the regulation underlying AGF signaling pathway may contribute to develop a new clinical strategy for ischemic vascular diseases.

Angiopoietins contribute to lung development by regulating pulmonary vascular network formation

Angiopoietin (Ang) signaling through the Tie2 receptor regulates vasculature. The role of Ang signaling in pulmonary hypertension is well investigated, but its role in lung development is not elucidated. Here, we show that the Tie2 agonist ligand, Ang1, was detected in lung tissue at birth and its expression gradually increased in mice, whereas its antagonist Ang2 was abundant at birth and decreased inversely with Ang1. Mice expressing the potent chimeric Ang1 protein COMP-Ang1 in surfactant protein C (SPC)-positive lung epithelial cells, showed 50% lethality at birth due to respiratory failure. Surviving mice displayed impaired adaptive responsive respiratory function. Histological analysis revealed that pulmonary artery and alveolar structure were significantly dilated, and alveolar density was decreased to approximately a third of controls. Thus, the precise regulation of Tie2 signaling through an Ang1/Ang2 expression switch is important to construct a mature lung vascular network system required for normal lung development.

Human Papillomavirus Genotype Distribution in Cervical Intraepithelial Neoplasia Grade 2/3 and Invasive Cervical Cancer in Japanese Women

OBJECTIVE Human papillomavirus vaccines are being introduced worldwide and are expected to reduce the incidence of cervical cancer. Here we report a cross-sectional study using a validated human papillomavirus genotyping method to reveal the human papillomavirus prevalence and genotype distribution in Japanese women with cervical intraepithelial neoplasia Grade 2/3 and invasive cervical cancer. METHODS Cervical exfoliated cells were collected from 647 patients with abnormal cervical histology (cervical intraepithelial neoplasia Grade 2, n = 164; cervical intraepithelial neoplasia Grade 3, n = 334; and invasive cervical cancer, n = 149), and subjected to the PGMY-PCR-based genotyping assay. The association between human papillomavirus infection and lesion severity was calculated using a prevalence ratio. RESULTS Overall, the prevalence of human papillomavirus deoxyribonucleic acid was 96.3% in cervical intraepithelial neoplasia Grade 2, 98.8% in cervical intraepithelial neoplasia Grade 3 and 88.0% in invasive cervical cancer (97.8% in squamous cell carcinoma and 71.4% in adenocarcinoma). The three most prevalent types were as follows: human papillomavirus 16 (29.3%), human papillomavirus 52 (27.4%) and human papillomavirus 58 (22.0%) in cervical intraepithelial neoplasia Grade 2; human papillomavirus 16 (44.9%), human papillomavirus 52 (26.0%) and human papillomavirus 58 (17.4%) in cervical intraepithelial neoplasia Grade 3; and human papillomavirus 16 (47.7%), human papillomavirus 18 (23.5%) and human papillomavirus 52 (8.7%) in invasive cervical cancer. The prevalence ratio of human papillomavirus 16 was significantly higher in cervical intraepithelial neoplasia Grade 3 compared with cervical intraepithelial neoplasia Grade 2 (prevalence ratio, 1.62; 95% confidence interval, 1.26-2.13) and in squamous cell carcinoma compared with cervical intraepithelial neoplasia Grade 3 (prevalence ratio, 1.55; 95% confidence interval, 1.25-1.87). Multiple infections decreased from cervical intraepithelial neoplasia Grade 2/3 (38.4/29.6%) to invasive cervical cancer (14.1%), whereas co-infections with human papillomavirus 16/52/58 were found in cervical intraepithelial neoplasia Grade 2/3. CONCLUSIONS The results of this study provide pre-vaccination era baseline data on human papillomavirus type distribution in Japanese women and serve as a reliable basis for monitoring the future impact of human papillomavirus vaccination in Japan.

Pregnancy Outcomes After Abdominal Radical Trachelectomy for Early-Stage Cervical Cancer: A 13-Year Experience in a Single Tertiary-Care Center.

Objective To investigate pregnancy outcomes in women after abdominal radical trachelectomy (RT) for early-stage cervical cancer. Methods The patients’ background, fertility, and pregnancy outcomes were reviewed in a total of 61 pregnancies in 48 of 172 women who underwent abdominal RT at Keio University Hospital between September 2002 and December 2013. Results There were 5 women with stage IA1, 2 with stage IA2, and 41 with stage IB1. Histological types were as follows: squamous cell carcinoma (n = 36), adenocarcinoma (n = 10), and adenosquamous cell carcinoma (n = 2). The pregnancy rate of women attempting to conceive after abdominal RT was 44% (48/109). The mean ± SD duration from abdominal RT to conception was 3.1 ± 1.9 years. Of 61 pregnancies, 42 pregnancies were achieved by fertility treatment (in vitro fertilization-embryo transfer, 39; intrauterine insemination, 3). After excluding one pregnancy without detailed clinical information, there were 42 live births (5 in 22–27 weeks, 11 in 28–33weeks, 20 in 34–36 weeks, and 6 in 37–38 weeks), 13 miscarriages, and 5 ongoing pregnancies. While there were 10 first trimester miscarriages, 3 pregnancies ended in the second trimester owing to chorioamnionitis. The mean gestational age at birth was 33 weeks of pregnancy. Thirty-seven neonates were appropriate-for-date, and one was small-for-date. Six pregnancies exhibited massive bleeding from the residual cervix in the late pregnancy. Preterm birth less than 34 weeks of pregnancy was related to premature rupture of the membrane (P < 0.05). Chorioamnionitis was evident in 9 of 11 pregnancies with preterm premature rupture of the membrane followed by birth at less than 34 weeks of pregnancy. No parturients exhibited lochiometra and endometritis postpartum. Conclusions Abdominal RT provided favorable pregnancy outcomes, and fertility treatment could be advantageous to conception. Massive bleeding from the residual cervix as well as ascending infection might be characteristic features during pregnancy after abdominal RT.

CITRUS, cervical cancer screening trial by randomization of HPV testing intervention for upcoming screening: Design, methods and baseline data of 18,471 women

BACKGROUND To assess the efficacy of screening with concurrent liquid-based cytology and human papillomavirus (HPV) testing for primary cervical cancer screening, we initiated a randomized trial entitled CervIcal cancer screening Trial by Randomization of HPV testing intervention for Upcoming Screening (CITRUS). METHODS Between June 2013 and March 2015, women aged 30-64 years of age who participated in a regular cervical cancer screening program (every 2 years) were invited to enrollment of our study. After giving their informed consent, 18,402 women were randomly assigned to liquid-based cytology as the control group (n=9145) or to HPV DNA testing with liquid-based cytology as the intervention group (n=9257). We subsequently compared the incidence rate of cervical intraepithelial neoplasia (CIN), the rate of false positive tests and the rate of overdiagnosis, as well as assessing the risks and benefits of receiving screening for women in both groups. The primary outcome of our study was the incidence of cervical intraepithelial neoplasia grade 3 or worse (CIN3+) during the study period of around 6 years. RESULTS In the control group, 97.9% of women were NILM, and 2.06% ASC-US or worse (ASC-US+). In the intervention group, 87.13% of women were NILM/HPV negative, 0.72% ASC-US/HPV negative, 10.34% NILM/HPV positive, 0.69% ASC-US/HPV positive, 0.90% worse than ASC-US/either HPV. Positive HPV testing was not linearly related to age in our study. CONCLUSIONS Insights from CITRUS will provide future prospects for cervical cancer screening focused on the use of HPV testing in Japan. CLINICAL TRIAL REGISTRATION NUMBER NCT01895517, UMIN000010843, TRIUC1312.