Insulin-Like Growth Factor-II Regulates the Expression of Vascular Endothelial Growth Factor by the Human Keratinocyte Cell Line HaCaT

Abnormal dermal microvascular endothelial cells in psoriatic excessive angiogenesis

Psoriasis is characterized by excessive angiogenesis, with increased distortion and dilation of the dermal blood vessels. These vascular alterations are ascribed, at least in part, to the changes in dermal microvascular endothelial cell functions. However, despite the recognition of vascular normalization as an emerging strategy for the treatment of psoriasis, in-depth studies of human dermal microvascular endothelial cells (HDMECs) have been missing. The difficulty of isolation and culture of HDMECs has impeded the study of endothelial dysfunction in psoriasis. Researchers have done a great deal of work to study the abnormal characteristics of keratinocytes, fibroblasts, and leukocytes in psoriatic skin tissue. Recently, with successful isolation of HDMECs from psoriasis, great progress has been made in the elucidation of the pathogenic role of these cells in psoriasis. It is of great therapeutic significance to study the molecular mechanism of HDMECs in psoriasis. We review here the abnormalities of HDMECs in psoriasis.

Exploring the Regulators of Keratinization: Role of BMP-2 in Oral Mucosa

The oral mucosa functions as a physico-chemical and immune barrier to external stimuli, and an adequate width of the keratinized mucosa around the teeth or implants is crucial to maintaining them in a healthy and stable condition. In this study, for the first time, bulk RNA-seq analysis was performed to explore the gene expression of laser microdissected epithelium and lamina propria from mice, aiming to investigate the differences between keratinized and non-keratinized oral mucosa. Based on the differentially expressed genes (DEGs) and Gene Ontology (GO) Enrichment Analysis, bone morphogenetic protein 2 (BMP-2) was identified to be a potential regulator of oral mucosal keratinization. Monoculture and epithelial-mesenchymal cell co-culture models in the air-liquid interface (ALI) indicated that BMP-2 has direct and positive effects on epithelial keratinization and proliferation. We further performed bulk RNA-seq of the ALI monoculture stimulated with BMP-2 in an attempt to identify the downstream factors promoting epithelial keratinization and proliferation. Analysis of the DEGs identified, among others, IGF2, ID1, LTBP1, LOX, SERPINE1, IL24, and MMP1 as key factors. In summary, these results revealed the involvement of a well-known growth factor responsible for bone development, BMP-2, in the mechanism of oral mucosal keratinization and proliferation, and pointed out the possible downstream genes involved in this mechanism.

d-mannose blocks the interaction between keratinocytes and Th17 cells to alleviate psoriasis by inhibiting HIF-1α/CCL20 in mice

Psoriasis is an autoimmune chronic inflammatory skin disease with an unclear pathogenesis that is difficult to cure, causing serious physical and mental burdens for patients. Previous research showed that a mutually reinforcing vicious cycle caused by keratinocytes (KC) and a variety of immune cells plays an important role in psoriatic inflammation. d-Mannose, a widely distributed metabolite in the body, has been found to treat several metabolic diseases, but its impact on psoriasis remains unknown. Our study aims to investigate the effects of d-mannose on psoriasis and its specific mechanism. Here, we found that d-mannose alleviates psoriasis in mice both as oral and topical agents. Specifically, d-mannose down-regulated the expression of hypoxia-inducible factor 1A(HIF-1α) and inhibited the expression of chemokine CCL20 in keratinocytes, thereby inhibiting the local infiltration of Th17 cells and breaking the cycle of keratinocytes-Th17 cells. Overall, our study indicates that d-mannose alleviates cutaneous inflammation in psoriasis by inhibiting the HIF-1α/CCL20/Th17 cells axis, and d-mannose has the potential to be used as an oral and topical agent in the treatment of psoriasis.

Effect of Azelaic Acid on Psoriasis Progression Investigated Based on Phosphatidylinositol 3-Kinase (PI3K)/Protein Kinase B (AKT) Signaling Pathway

OBJECTIVE

To probe into the effect of azelaic acid on psoriasis based on the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway.

METHODS

Psoriasis gene expression data were downloaded from the GEO database for differential expression analysis to identify differentially expressed genes (DEGs). KEGG and GSEA analyses were performed to identify important signaling pathways that may be involved in psoriasis progression for subsequent validation. Thirty-six C57BL/6 mice aged 8 weeks old were randomly assigned into the blank control group (n = 9), negative control group (n = 9), psoriasis model group (n = 9), and azelaic acid treat group (n = 9). Mice models of psoriasis were prepared with imiquimod (IMQ) in the latter two groups, and azelaic acid ointment was applied in azelaic acid treat group. Then, hematoxylin-eosin (HE) staining was carried out to detect the effect of azelaic acid on the pathological damage of mice models of psoriasis in each group. HaCaT cells cultured in vitro were divided into blank control group, negative control group (addition of azelaic acid), IL-17 group (20 ng/mL) and IL-17+azelaic acid group, with 3 replicates for each group. Immunofluorescence assay and Western blotting were used to detect the protein expression of PI3K/AKT signaling pathway related molecules.

RESULTS

KEGG analysis showed that DEGs were significantly enriched in PI3K-AKT signaling pathway. GSEA analysis showed that PI3K and MTOR signaling pathways were up-regulated in psoriasis, while AUTOPHAGY signaling pathway was down-regulated. HE staining showed that azelaic acid could significantly inhibit the local skin injury in mice caused by IMQ-induced psoriasis. Moreover, azelaic acid can inhibit the expression of PI3K/AKT signaling pathway related proteins phosphorylated (p)-PI3K, p-AKT, p-mammalian target of rapamycin (mTOR), vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), angiogenin-1 and hypoxia-inducible factor-1α (HIF-1α). These results imply that azelaic acid may inhibit the activation of PI3K/AKT signaling pathway and angiogenesis, thereby improving the symptoms of psoriasis.

CONCLUSION

Azelaic acid may inhibit the activation of PI3K/AKT signaling pathway and angiogenesis, thereby improving the symptoms of psoriasis.

Human Umbilical Cord-Derived Mesenchymal Stem Cells Ameliorate Skin Aging of Nude Mice Through Autophagy-Mediated Anti-Senescent Mechanism

Skin aging is a currently irreversible process, affected by increased oxidative stress, activated cellular senescence, and lacked regeneration of the dermal layer. Mesenchymal stem cells (MSCs), such as human umbilical cord-derived MSCs (hucMSCs), have pro-regeneration and anti-aging potencies. To explore whether hucMSCs can be used to treat skin aging, this study employed skin-aging model of nude mice to conduct in vivo assays, including biochemical analysis of superoxide dismutase (SOD) and malondialdehyde (MDA), gross observation, histopathological observation, and immunohistochemical analysis. To clarify how hucMSCs work on skin aging, this study employed skin-aging model of human dermal fibroblasts (HDFs) to conduct in vitro assays by applying conditional medium of hucMSCs (CMM), including wound healing assay, senescence staining, flow cytometric oxidative detection, real time PCR, and western blot analysis. The in vivo data demonstrated that hucMSCs dose-dependently removed wrinkles, smoothed skin texture, and increased dermal thickness and collagen production of aged skin by reversing SOD and MDA levels and up-regulating Col-1 and VEGF expressions, indicating anti-oxidative and pro-regenerative effects against skin aging. The in vitro data revealed that hucMSCs significantly reversed the senescence of HDFs by promoting cell migration, inhibiting ROS production, and restoring the overexpressions of oxidative and senescent markers through paracrine mode of action, and the paracrine mechanism was mediated by the inhibition of autophagy. This study provided novel knowledge regarding the anti-aging efficacy and paracrine mechanism of hucMSCs on skin, making hucMSCs-based therapy a promising regime for skin aging treatment.

Serum VEGF-C as an evaluation marker of disease activity in adult-onset Still's disease

In view of the possible involvement of vascular endothelial growth factor-C (VEGF-C) in pathogenesis of adult-onset Still's disease (AOSD) based on our previous genome-wide association study (GWAS) results, the primary objective of this study, therefore, was to investigate the correlations between the content of VEGF-C in serum and clinical and biochemical markers of AOSD. Blood samples were collected from 80 patients with AOSD, 26 with rheumatoid arthritis (RA), 30 with systemic lupus erythematosus (SLE) and 31 healthy control subjects. The serum VEGF-C levels were determined using an enzyme-linked immunosorbent assay (ELISA). Statistical analysis and comparisons were conducted. A significantly higher serum VEGF-C level was observed in patients with AOSD than in HC. Serum VEGF-C levels had high AUC value of 0.8145 for distinguishing AOSD group from healthy group with sensitivity of 0.7097 and specificity of 0.8250. It also showed good diagnostic value to differentiate AOSD from other autoinflammatory diseases with sensitivity of 0.7500 and specificity of 0.5500. AOSD patients with fever, arthralgia, skin rash, sore throat, lymphadenopathy, splenomegaly hepatomegaly and pleuritis, had a higher level than those who did not have these symptoms (p = 0.0012, p = 0.0092, p = 0.0056, p = 0.0123, p = 0.0068, p = 0.0030, p = 0.0020, and p = 0.0018, respectively). The serum VEGF-C levels were also positively correlated with laboratory features and several cytokines related to AOSD disease activity. In conclusion, our study unveiled a close association between serum VEGF-C levels and AOSD including disease activity and clinical hematological manifestations, suggesting the potential utility of VEGF-C as a candidate biomarker to assess disease activity in AOSD.

Monochorionic twins with selective fetal growth restriction: insight from placental whole-transcriptome analysis

BACKGROUND

The underlying pathomechanism in placenta-related selective fetal growth restriction in monochorionic diamniotic twin pregnancy is not known.

OBJECTIVE

This study aimed to investigate any differences in placental transcriptomic profile between the selectively growth-restricted twins and the normally grown cotwins in monochorionic diamniotic twin pregnancies.

STUDY DESIGN

This was a prospective study of monochorionic diamniotic twin pregnancies complicated by selective fetal growth restriction. Placental biopsy specimens were obtained from the subjects in the delivery suite. The placental transcriptome of the selectively growth-restricted twin was compared with that of the normally grown cotwin. This study was divided into 2 stages: (1) gene discovery phase in which placental tissues from 5 monochorionic diamniotic twin pregnancies complicated by selective fetal growth restriction plus 2 control twin pregnancies underwent transcriptome profiling, and transcriptome profiling was carried out using whole-genome RNA sequencing; and (2) validation phase in which placental tissues from 13 monochorionic diamniotic twin pregnancies with selective fetal growth restriction underwent RNA and protein validation. RNA and protein expression levels of candidate genes were determined using quantitative real-time polymerase chain reaction and immunohistochemistry staining.

RESULTS

A total of 1429 transcripts were differentially expressed in the placentae of selectively growth-restricted twin pairs, where 610 were up-regulated and 819 were down-regulated. Endoplasmic reticulum lectin and mannose 6-phosphate receptor were consistently differentially up-regulated in all placentae of selectively growth-restricted twins. Quantitative real-time polymerase chain reaction and immunohistochemistry staining were used to validate the results (P<.05).

CONCLUSION

The expression of endoplasmic reticulum lectin and mannose 6-phosphate receptor, which are important for angiogenesis and fetal growth, was significantly increased in the placentae of selectively growth-restricted twin of a monochorionic twin pair.

The IGF-II-Insulin Receptor Isoform-A Autocrine Signal in Cancer: Actionable Perspectives

Insulin receptor overexpression is a common event in human cancer. Its overexpression is associated with a relative increase in the expression of its isoform A (IR^A), a shorter variant lacking 11 aa in the extracellular domain, conferring high affinity for the binding of IGF-II along with added intracellular signaling specificity for this ligand. Since IGF-II is secreted by the vast majority of malignant solid cancers, where it establishes autocrine stimuli, the co-expression of IGF-II and IR^A in cancer provides specific advantages such as apoptosis escape, growth, and proliferation to those cancers bearing such a co-expression pattern. However, little is known about the exact role of this autocrine ligand–receptor system in sustaining cancer malignant features such as angiogenesis, invasion, and metastasis. The recent finding that the overexpression of angiogenic receptor kinase EphB4 along with VEGF-A is tightly dependent on the IGF-II/IR^A autocrine system independently of IGFIR provided new perspectives for all malignant IGF2omas (those aggressive solid cancers secreting IGF-II). The present review provides an updated view of the IGF system in cancer, focusing on the biology of the autocrine IGF-II/IR^A ligand–receptor axis and supporting its underscored role as a malignant-switch checkpoint target.

Prognostic value of insulin-like growth factor 2 mRNA-binding protein 3 and vascular endothelial growth factor-A in patients with primary non-small-cell lung cancer

Insulin-like growth factor 2 mRNA-binding protein 3 (IMP3) and vascular endothelial growth factor-A (VEGF-A) may play important roles in the process of tumor progression and tumor angiogenesis. The aim of the present study was to examine the co-expression of IMP3 and VEGF-A in primary human non-small cell lung cancer (NSCLC), to investigate the association between these two expression levels and determine the clinicopathological implications, including changes to microvessel density (MVD), and to assess the prognostic value of co-expression. Using immunohistochemical staining, the expression of IMP3, VEGF-A and CD34 expression was detected in 128 primary NSCLC tissue samples. According to the expression of IMP3 and VEGF-A, the cases were divided into four groups. Next, the clinicopathological features, MVD and survival time were investigated across the different groups. The immunohistochemical analyses demonstrated that there was a significant correlation between IMP3 and VEGF-A expression in NSCLC (r=0.181; P=0.041). Co-expression of IMP3 and VEGF-A was significantly associated with larger primary tumor size (P=0.016), poorer differentiation (P=0.014), more advanced Tumor-Node-Metastasis stage (P=0.012), increased MVD (P=0.004) and positive lymph node metastasis (P=0.002). Survival analysis demonstrated that cases with IMP3 and VEGF-A double-positive staining were significantly associated with lower survival rates compared with cases with double-negative staining (P=0.039). In the early NSCLC (I–IIa) subgroup, the mean survival time of the double-positive staining group was significantly shorter compared with that of the double-negative staining group (P=0.015). Co-expression of IMP3 and VEGF-A was associated with angiogenesis and a poorer prognosis in NSCLC, and may therefore play a critical role in NSCLC progression.

Insulin growth factor 2 (IGF2) as an emergent target in psychiatric and neurological disorders. Review

Insulin-like growth factor 2 (IGF2) is abundantly expressed in the central nervous system (CNS). Recent evidence highlights the role of IGF2 in the brain, sustained by data showing its alterations as a common feature across a variety of psychiatric and neurological disorders. Previous studies emphasize the potential role of IGF2 in psychiatric and neurological conditions as well as in memory impairments, targeting IGF2 as a pro-cognitive agent. New research on animal models supports that upcoming investigations should explore IGF2's strong promising role as a memory enhancer. The lack of effective treatments for cognitive disturbances as a result of psychiatric diseases lead to further explore IGF2 as a promising target for the development of new pharmacology for the treatment of memory dysfunctions. In this review, we aim at gathering all recent relevant studies and findings on the role of IGF2 in the development of psychiatric diseases that occur with cognitive problems.

Cancer cell-secreted IGF2 instigates fibroblasts and bone marrow-derived vascular progenitor cells to promote cancer progression

Local interactions between cancer cells and stroma can produce systemic effects on distant organs to govern cancer progression. Here we show that IGF2 secreted by inhibitor of differentiation (Id1)-overexpressing oesophageal cancer cells instigates VEGFR1-positive bone marrow cells in the tumour macroenvironment to form pre-metastatic niches at distant sites by increasing VEGF secretion from cancer-associated fibroblasts. Cancer cells are then attracted to the metastatic site via the CXCL5/CXCR2 axis. Bone marrow cells transplanted from nude mice bearing Id1-overexpressing oesophageal tumours enhance tumour growth and metastasis in recipient mice, whereas systemic administration of VEGFR1 antibody abrogates these effects. Mechanistically, IGF2 regulates VEGF in fibroblasts via miR-29c in a p53-dependent manner. Analysis of patient serum samples showed that concurrent elevation of IGF2 and VEGF levels may serve as a prognostic biomarker for oesophageal cancer. These findings suggest that the Id1/IGF2/VEGF/VEGFR1 cascade plays a critical role in tumour-driven pathophysiological processes underlying cancer progression.

Serum concentration and skin tissue expression of insulin-like growth factor 2 in canine generalized demodicosis

BACKGROUND

There is increasing evidence that insulin-like growth factor-2 (IGF-2) levels are altered in skin injury; there are no data evaluating the serum concentration and skin tissue expression of IGF-2 in canine generalized demodicosis.

HYPOTHESIS/OBJECTIVES

To assess serum concentrations of IGF-2 collected from dogs with generalized demodicosis compared to healthy dogs and to determine the location of IGF-2 in the skin of affected dogs.

METHODS

Blood and skin samples were collected from 12 dogs of differing breeds and gender at 1-2 years of age that had a confirmed diagnosis of generalized demodicosis. Age-matched control skin and blood samples were collected from 11 normal dogs of different breeds and gender. Serum IGF-2 concentrations were measured by enzyme-linked immunosorbent assay. Skin tissue expression of IGF-2 was analysed by immunohistochemical methods.

RESULTS

Serum concentration and skin tissue expression of IGF-2 were increased in dogs with generalized demodicosis compared with control dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

These findings indicate that keratinocytes, histiocytes and fibrocytes in the dermis are positive for IGF-2; they may be a source of the elevated serum IGF-2 levels in dogs with generalized demodicosis.

IGF2: an endocrine hormone to improve islet transplant survival

In the week following pancreatic islet transplantation, up to 50% of transplanted islets are lost due to apoptotic cell death triggered by hypoxic and pro-inflammatory cytokine-mediated cell stress. Thus, therapeutic approaches designed to protect islet cells from apoptosis could significantly improve islet transplant success. IGF2 is an anti-apoptotic endocrine protein that inhibits apoptotic cell death through the mitochondrial (intrinsic pathway) or via antagonising activation of pro-inflammatory cytokine signalling (extrinsic pathway), in doing so IGF2 has emerged as a promising therapeutic molecule to improve islet survival in the immediate post-transplant period. The development of novel biomaterials coated with IGF2 is a promising strategy to achieve this. This review examines the mechanisms mediating islet cell apoptosis in the peri- and post-transplant period and aims to identify the utility of IGF2 to promote islet survival and enhance long-term insulin independence rates within the setting of clinical islet transplantation.

Bisphenol A enhances kisspeptin neurons in anteroventral periventricular nucleus of female mice

Bisphenol-A (BPA), an environmental estrogen, adversely affects female reproductive health. However, the underlying mechanisms remain largely unknown. We found that oral administration (p.o.) of BPA (20  μg/kg) to adult female mice at proestrus, but not at estrus or diestrus, significantly increased the levels of plasma E₂, LH and FSH, and Gnrh mRNA within 6  h. The administration of BPA at proestrus, but not at diestrus, could elevate the levels of Kiss1 mRNA and kisspeptin protein in anteroventral periventricular nucleus (AVPV) within 6  h. In contrast, the level of Kiss1 mRNA in arcuate nucleus (ARC) was hardly altered by BPA administration. In addition, at proestrus, a single injection (i.c.v.) of BPA dose-dependently enhanced the AVPV-kisspeptin expression within 6  h, this was sensitive to E₂ depletion by ovariectomy and an estrogen receptor α (ERα) antagonist. Similarly, the injection of BPA (i.c.v.) at proestrus could elevate the levels of plasma E₂, LH, and Gnrh mRNA within 6  h in a dose-dependent manner, which was blocked by antagonists of GPR54 or ERα. Injection of BPA (i.c.v.) at proestrus failed to alter the timing and peak concentration of LH-surge generation. In ovariectomized mice, the application of E₂ induced a dose-dependent increase in the AVPV-Kiss1 mRNA level, indicating 'E₂-induced positive feedback', which was enhanced by BPA injection (i.c.v.). The levels of Erα (Esr1) and Erβ (Esr2) mRNAs in AVPV and ARC did not differ significantly between vehicle-and BPA-treated groups. This study provides in vivo evidence that exposure of adult female mice to a low dose of BPA disrupts the hypothalamic-pituitary-gonadal reproductive endocrine system through enhancing AVPV-kisspeptin expression and release.

SIRT1 inhibition restores apoptotic sensitivity in p53-mutated human keratinocytes

Mutations to the p53 gene are common in UV-exposed keratinocytes and contribute to apoptotic resistance in skin cancer. P53-dependent activity is modulated, in part, by a complex, self-limiting feedback loop imposed by miR-34a-mediated regulation of the lysine deacetylase, SIRT1. Expression of numerous microRNAs is dysregulated in squamous and basal cell carcinomas; however the contribution of specific microRNAs to the pathogenesis of skin cancer remains untested. Through use of RNAi, miRNA target site blocking oligonucleotides and small molecule inhibitors, this study explored the influence of p53 mutational status, SIRT1 activity and miR-34a levels on apoptotic sensitivity in primary (NHEK) and p53-mutated (HaCaT) keratinocyte cell lines. SIRT1 and p53 are overexpressed in p53-mutated keratinocytes, whilst miR-34a levels are 90% less in HaCaT cells. HaCaTs have impaired responses to p53/SIRT1/miR-34a axis manipulation which enhanced survival during exposure to the chemotherapeutic agent, camptothecin. Inhibition of SIRT1 activity in this cell line increased p53 acetylation and doubled camptothecin-induced cell death. Our results demonstrate that p53 mutations increase apoptotic resistance in keratinocytes by interfering with miR-34a-mediated regulation of SIRT1 expression. Thus, SIRT1 inhibitors may have a therapeutic potential for overcoming apoptotic resistance during skin cancer treatment.

Regulation of hypoxia-inducible factor-1α (HIF-1α) expression by interleukin-1β (IL-1 β), insulin-like growth factors I (IGF-I) and II (IGF-II) in human osteoarthritic chondrocytes

OBJECTIVE

Hypoxia-inducible factor 1 alpha regulates genes related to cellular survival under hypoxia. This factor is present in osteroarthritic chondrocytes, and cytokines, such as interleukin-1 beta, participate in the pathogenesis of osteoarthritis, thereby increasing the activities of proteolytic enzymes, such as matrix metalloproteinases, and accelerating cartilage destruction. We hypothesize that Hypoxia Inducible Factor-1 alpha (HIF-1α) can regulate cytokines (catabolic action) and/or growth factors (anabolic action) in osteoarthritis. The purpose of this study was to investigate the modulation of HIF-1α in human osteoarthritic chondrocytes by interleukin-1 beta (IL-1β) and insulin-like growth factors I (IGF-I) and II (IGF-II) and to determine the involvement of the phosphatidylinositol-3-kinase (PI-3K) pathway in this process.

METHODS

Human osteroarthritic chondrocytes were stimulated with IL-1β, IGF-I and IGF-II and LY294002, a specific inhibitor of PI-3K. Nuclear protein levels and gene expression were analyzed by western blot and quantitative reverse transcription-polymerase chain reaction analyses, respectively.

RESULTS

HIF-1α expression was upregulated by IL-1β at the protein level but not at the gene level. IGF-I treatment resulted in increases in both the protein and mRNA levels of HIF-1α , whereas IGF-II had no effect on its expression. However, all of these stimuli exploited the PI-3K pathway.

CONCLUSION

IL-1β upregulated the levels of HIF-1α protein post-transcriptionally, whereas IGF-I increased HIF-1α at the transcript level. In contrast, IGF-II did not affect the protein or gene expression levels of HIF-1α . Furthermore, all of the tested stimuli exploited the PI-3K pathway to some degree. Based on these findings, we are able to suggest that Hypoxia inducible Factor-1 exhibits protective activity in chondrocytes during osteoarthritis.

Sonic Hedgehog on microparticles and neovascularization

Neovascularization represents a pivotal process consisting in the development of vascular network during embryogenesis and adult life. Postnatally, it arises mainly through angiogenesis, which has physiological and pathological roles in health and disease. Blood vessel formation results as tightly regulated multistep process which needs coordination and precise regulation of the balance of proangiogenic and antiangiogenic factors. Sonic Hedgehog (SHH), a morphogen belonging to Hedgehog (HH) family proteins, is implicated in a remarkably wide variety of process, including vessel development. Recent evidence demonstrate that, in addition to the classic factors, microvesicles (MVs), both microparticles (MPs) and exosomes, small vesicles released distinct cellular compartments, are involved in modulation of neovascularization. MPs generated from T lymphocytes undergoing both activation and apoptosis harbor at their surface SHH and play a crucial role in modulation of neovascularization. They are able to modulate the different steps implicated in angiogenesis process in vitro and to enhance postischemic neovascularization in vivo. As the consequence, we suggest that the MPs carrying SHH contribute to generation of a vascular network and may represent a new therapeutic approach to treat pathologies associated with failed angiogenesis.

Hypoxia-induced insulin-like growth factor II contributes to retinal vascularization in ocular development

In ocular development, retinal physiological hypoxia in response to the retinal metabolic activity controls retinal vascular development, which is regulated by variable angiogenic factors. Herein, we demonstrated that hypoxia-induced IGF-II could contribute to retinal vascularization in ocular development. In the developing retina, IGF-II expression appears to be predominant on retinal vessels, which was chronologically increased and peaked during active retinal angiogenesis similar to VEGF expression. Under hypoxic condition, IGF-II as well as VEGF was significantly up-regulated in retinal vascular endothelial cells. In addition, IGF-II treatment could also increase VEGF expression in retinal vascular endothelial cells. The VEGF expression induced by IGF-II was mediated by ERK-1/2 activation. Moreover, IGF-II strongly promoted angiogenic processes of migration and tube formation of retinal microvascular endothelial cells. In conclusion, our results provided that hypoxia-induced IGF-II may regulate retinal vascular development not only directly by IGF-II-mediated angiogenic activity, but also indirectly by IGF-II-induced VEGF expression. Therefore, the potential contribution of IGF-II to pathological retinal angiogenesis should be furthermore explored for the development of novel treatments to vaso-proliferative retinopathies.

IGF2, IGF binding protein 1, and matrix metalloproteinases 2 and 9 in implantation-stage endometrium following immunoneutralization of vascular endothelial growth factor in the rhesus monkey

Blastocyst implantation in the rhesus monkey is inhibited by administration of antibody against vascular endothelial growth factor (VEGF) A during peri-implantation period with no change in the circulatory concentrations of estradiol, progesterone, and VEGF. In this study, we have investigated the effect of administration of a MAB to VEGFA on days 5 and 10 after ovulation upon the mRNA expression, immunopositive protein expression, and immunohistological localization of IGF2, IGF binding protein 1 (IGFBP1) and matrix metalloproteinases (MMPs) 2 and 9 in the implantation-stage endometrium collected on day 13 after ovulation from fecund cycles of rhesus monkeys. The comparison between isotype-matched IgG (control; n=8)- and VEGF antibody (VEGF Mab; n=8)-treated animals revealed higher (P<0.05) IGF2 in lacunar and villous syncytiotrophoblasts, trophoblast cell columns, migrating extravillous trophoblast cells, and endovascular trophoblast cells in control animals, but with no change in the various cell types of maternal endometrium between the two groups. No change in IGFBP1 expression in the endometrium was observed between the two groups. MMPs 2 and 9 were detected in syncytiotrophoblast in lacunae and villi, trophoblast cell columns, and extravillous trophoblast cells in control samples. MMP9 transcript expression in maternal endometrium and its immunopositivity in endometrial stroma and trophoblast cells were lower (P<0.05) with no change in MMP2 level in VEGF Mab-exposed samples compared with those in control samples. A functional network involving VEGF, IGF2, and MMP9 in early placental trophoblast cells and maternal endometrium appears to be important for normal placentation.

Regulation of hypoxia inducible factors (HIF) in hypoxia and normoxia during placental development

During the first trimester of pregnancy the human placenta develops in an hypoxic environment caused by the occlusion of uterine spiral arterioles by extravillous trophoblasts (EVT). This period of low oxygen tension is crucial for successful pregnancy. In low oxygen environments, Hypoxia Inducible Factors (HIF) are the main regulators in the transcription of a number of genes. Target genes can induce anaerobic processes, reducing oxygen consumption, or promote angiogenesis, which establishes and enhances the vascular environment. The HIFs can function throughout all stages of placental differentiation and growth both in normal and pathological pregnancies (compromised by hypoxia/ischemia). Interestingly, HIFs respond to a multitude of changes during pregnancy, including 1) low oxygen, 2) renin-angiotensin system (RAS), 3) cytokines, and 4) growth factors, all of which regulate placental function. This review explores oxygen-dependent and oxygen-independent regulation and the role of HIF in placental development and differentiation.

Cardiovascular Disease and Risk Factors in Patients with Psoriasis and Psoriatic Arthritis

Objective.

Patients with psoriasis and psoriatic arthritis (PsA) have an increased incidence of cardiovascular disease (CVD) and cardiovascular risk factors such as smoking, hypertension, and metabolic syndrome compared to the normal population. Patients with psoriasis and PsA may also have increased risk from nonconventional risk factors such as raised levels of homocysteine and excessive alcohol consumption. We conducted a comprehensive review of the literature on CVD and all cardiovascular risk factors in patients with psoriasis and PsA.

Methods.

Data sources: All studies identified from a Medline (www.ncbi.nlm.nih.gov) search pertaining to CVD, individual risk factors in psoriasis, and PsA were included. Study selection: Studies included a healthy reference population, were published between 1975 and 2009, and were written in English.

Results.

Our search yielded 14 studies that documented rates of CVD in patients with psoriasis and PsA compared to controls. Substantial evidence points to elevated risk of CVD in patients with psoriasis and PsA.

Conclusion.

It remains difficult to conclude if risk factors are caused by psoriasis or share a common pathogenesis. Physicians treating patients with psoriasis and PsA must be aware of all potential cardiovascular risk factors in their patients.

Beyond oxygen: complex regulation and activity of hypoxia inducible factors in pregnancy

In the first trimester the extravillous cytotrophoblast cells occlude the uterine spiral arterioles creating a low oxygen environment early in pregnancy, which is essential for pregnancy success. Paradoxically, shallow trophoblast invasion and defective vascular remodelling of the uterine spiral arteries in the first trimester may result in impaired placental perfusion and chronic placental ischemia and hypoxia later in gestation leading to adverse pregnancy outcomes. The hypoxia inducible factors (HIFs) are key mediators of the response to low oxygen. We aimed to elucidate mechanisms of regulation of HIFs and the role these may play in the control of placental differentiation, growth and function in both normal and pathological pregnancies. The Pubmed database was consulted for identification of the most relevant published articles. Search terms used were oxygen, placenta, trophoblast, pregnancy, HIF and hypoxia. The HIFs are able to function throughout all aspects of normal and abnormal placental differentiation, growth and function; during the first trimester (physiologically low oxygen), during mid-late gestation (where there is adequate supply of blood and oxygen to the placenta) and in pathological pregnancies complicated by placental hypoxia/ischemia. During normal pregnancy HIFs may respond to complex alterations in oxygen, hormones, cytokines and growth factors to regulate placental invasion, differentiation, transport and vascularization. In the ever-changing environment created during pregnancy, the HIFs appear to act as key mediators of placental development and function and thereby are likely to be important contributors to both normal and adverse pregnancy outcomes.

Calcitonin gene-related peptide increases proliferation of human HaCaT keratinocytes by activation of MAP kinases

Psoriasis is a chronic disease characterized by keratinocyte hyperproliferation and inflammation. It has been demonstrated that the expression of calcitonin gene-related peptide (CGRP) is elevated in psoriasis lesions and CGRP-containing neuropeptide nerve fibers are denser in the psoriatic epidermis. CGRP has been previously described to influence proliferation of several cell types, such as Schwann cell, tracheal epithelial cells, and human gingival fibroblasts. In the present study, we determined the effect of CGRP on HaCaT keratinocyte proliferation and the role of mitogen-activated protein kinases (MAPKs) in CGRP induced keratinocyte proliferation. Our data indicate CGRP increased [(3)H]-thymidine incorporation and MTT activity of HaCaT in a concentration-dependent manner. CGRP also enhanced serum-induced HaCaT cell proliferation. HaCaT cells cultured with CGRP had a significant increase in phosphorylated ERK1/2, p38 and JNK, and CGRP induced DNA synthesis was inhibited by PD 98059 or SB 203580, selective inhibitors of MAP kinase kinase (MEK, which is upstream from ERK) and p38, respectively. These findings suggest that HaCaT cell proliferate in response to CGRP, which is mediated by phosphorylation of ERK1/2 and p38 MAPK.

Preclinical targeting of the type I insulin-like growth factor receptor in adrenocortical carcinoma

CONTEXT

Drug therapy for adrenocortical carcinoma (ACC), a rare and lethal malignancy, is largely empirical and ineffective. New treatments directed at molecular targets critical to the pathophysiology of ACC may prove more efficacious.

OBJECTIVE

The objective of the study was to profile human adrenal tumors and ACC cell lines to assess activated IGF signaling and determine the efficacy of two IGF receptor (IGF-1R) antagonists alone and in combination with mitotane.

EXPERIMENTAL DESIGN

ACC cell lines that display or lack activated IGF signaling are used to assess the effects of two IGF-1R antagonists in cultured cells and ACC xenograft tumors.

RESULTS

Transcriptional profiling data derived from DNA microarray analysis of human adrenal tumors implicate IGF2 as the single highest up-regulated transcript in the vast majority of carcinomas. We show that the majority of ACC cell lines tested display constitutive IGF ligand production and activation of downstream effector pathways. Both IGF-1R antagonists cause significant dose-dependent growth inhibition in ACC cell lines. Furthermore, we observe that mitotane, the first-line adrenolytic drug used in patients with ACC, results in enhanced growth inhibition when used in combination with the IGF-1R antagonists. We next examined the activity of IGF-1R antagonists against ACC xenografts in athymic nude mice. IGF inhibition markedly reduced tumor growth greater than that observed with mitotane treatment, and combination therapy with mitotane significantly enhanced tumor growth suppression.

CONCLUSION

These findings establish a critical role of IGF signaling in ACC pathophysiology and provide rationale for use of targeted IGF-1R antagonists to treat adrenocortical carcinoma in future clinical trials.

Epidermal vascular endothelial growth factor production is required for permeability barrier homeostasis, dermal angiogenesis, and the development of epidermal hyperplasia: implications for the pathogenesis of psoriasis

Primary abnormalities in permeability barrier function appear to underlie atopic dermatitis and epidermal trauma; a concomitant barrier dysfunction could also drive other inflammatory dermatoses, including psoriasis. Central to this outside-inside view of disease pathogenesis is the epidermal generation of cytokines/growth factors, which in turn signal downstream epidermal repair mechanisms. Yet, this cascade, if sustained, signals downstream epidermal hyperplasia and inflammation. We found here that acute barrier disruption rapidly stimulates mRNA and protein expression of epidermal vascular endothelial growth factor-A (VEGF-A) in normal hairless mice, a specific response to permeability barrier requirements because up-regulation is blocked by application of a vapor-impermeable membrane. Moreover, epidermal vegf(-/-) mice display abnormal permeability barrier homeostasis, attributable to decreased VEGF signaling of epidermal lamellar body production; a paucity of dermal capillaries with reduced vascular permeability; and neither angiogenesis nor epidermal hyperplasia in response to repeated tape stripping (a model of psoriasiform hyperplasia). These results support a central role for epidermal VEGF in the maintenance of epidermal permeability barrier homeostasis and a link between epidermal VEGF production and both dermal angiogenesis and the development of epidermal hyperplasia. Because psoriasis is commonly induced by external trauma [isomorphic (Koebner) phenomenon] and is associated with a prominent permeability barrier abnormality, excess VEGF production, prominent angiogenesis, and epidermal hyperplasia, these results could provide a potential outside-inside mechanistic basis for the development of psoriasis.

Enhanced expression of Rab27A gene by breast cancer cells promoting invasiveness and the metastasis potential by secretion of insulin-like growth factor-II

In addition to the functions of transporting melanosome in melanocytes and releasing contents of lytic granules in CTLs, Rab27A was recently shown to be involved in exocytosis of insulin and chromaffin granules in endocrine cells; it was also reported to be expressed in an exceptionally broad range of specialized secretory cells. As autocrine and paracrine cytokines are essential for invasion and metastasis in some solid tumors, blocking them may be an effective strategy to prevent tumor dissemination. In the present study, we show that Rab27A is associated with invasive and metastatic potentials of human breast cancer cells. The overexpression of Rab27A protein redistributed the cell cycle and increased the invasive and metastatic abilities in breast cancer cells both in vitro and in vivo. We also certified that Rab27A conferred the invasive and metastatic phenotypes on breast cancer cells by promoting the secretion of insulin-like growth factor-II (IGF-II), which regulates the expression of p16, vascular endothelial growth factor, matrix metalloproteinase-9, cathepsin D, cyclin D1, and urokinase-type plasminogen activator. These data provide functional evidence that Rab27A acts as a novel mediator of invasion and metastasis promotion in human breast cancer cells, at least in part, through regulating the secretion of IGF-II, suggesting that synergistic suppression of Rab27A and IGF-II activities holds a promise for preventing breast cancer invasion and metastasis.

TCAP knockdown by RNA interference inhibits myoblast differentiation in cultured skeletal muscle cells

Null mutation of titin-cap (TCAP) causes limb-girdle muscular dystrophy type 2G (LGMD2G). LGMD2G patients develop muscle atrophy, and lose the ability to walk by their third decade. Previous findings suggest that TCAP regulates myostatin, a key regulator of muscle growth. We tested the hypothesis that TCAP knockdown with RNA interference will lead to differential expression of genes involved in muscle proliferation and differentiation, impairing muscle cell growth. mRNA from cultured cells treated with TCAP siRNA duplex constructs was analyzed using Northern blots and real-time RT-PCR. siRNA treatment decreased TCAP mRNA expression in differentiating muscle cells. Significant (p<0.05) decreases in mRNA were observed for myogenic regulatory factors. siRNA treatment also prevented development of the normal phenotype of muscle cells. Our findings suggest that TCAP knockdown with RNA interference alters normal muscle cell differentiation.

IGF2: epigenetic regulation and role in development and disease

Insulin-like growth factor II (IGF2) is perhaps the most intricately regulated of all growth factors characterized to date. Its gene is imprinted--only one allele is active, depending on parental origin--and this pattern of expression is maintained epigenetically in almost all tissues. IGF2 activity is further controlled through differential expression of receptors and IGF-binding proteins (IGFBPs) that determine protein availability. This complex and multifaceted regulation emphasizes the importance of accurate IGF2 expression and activity. This review will examine the regulation of the IGF2 gene and what it has revealed about the phenomenon of imprinting, which is frequently disrupted in cancer. IGF2 protein function will be discussed, along with diseases that involve IGF2 overexpression. Roles for IGF2 in sonic hedgehog (Shh) signaling and angiogenesis will also be explored.

Expression and localization of the activated mitogen-activated protein kinase in lesional psoriatic skin

Abnormalities in several signaling pathways and in the expression and/or activation of different transcription factors in psoriatic keratinocytes have been hypothesized to play a role in the pathophysiology of psoriasis. The mitogen-activated protein kinase (MAPK) cascades are among the best characterized of intracellular signaling pathways, and they play important roles in cell proliferation, differentiation, gene expression, and inflammation. We investigated the expression, activation and distribution of extracellular signal-regulated kinases (ERKs), p38 mitogen-activated protein kinases (p38 MAPK) and c-Jun N-terminal kinases (JNKs), using immunohistochemistry and Western blot in lesional psoriatic skin and normal control skin, to clarify the possible roles of these kinases involved in the pathogenesis of psoriasis. The immunoblot analysis demonstrated that activation of ERK1/2 and p38 MAPK increased in the lesional psoriatic skin. In addition, a significant increase in p-MEK (the upstream activator of ERK), and p-CREB (a downstream transcription factor of active ERK) was also found in our experiment. The immunohistochemical study showed that the levels of phosphorylated ERK1/2 and p38 MAPK were enhanced in lesional psoriatic skin compared with controls. Phosphorylated ERK1/2 and p38 exhibited clear nuclear localization throughout the epidermal part of lesional psoriatic skin. These findings suggested that ERK1/2 and p38 pathways were involved in the pathophysiology of psoriasis.

Angiogenesis in implantation

PROBLEM

Implantation failure and early pregnancy loss are common following natural conceptions and they are particularly important clinical hurdles to overcome following assisted reproduction attempts. The importance of adequate vascular development and maintenance during implantation has recently become a major focus of investigation.

MATERIALS AND METHODS

Review of current published literature was undertaken to summerize the cells and cell products that regulate tissue vascularity during implantation.

RESULTS

Vascular development at the maternal fetal interface can be regulated by a number of different cell types; two principal candidates are trophoblast and natural killer cells. A wide range of soluble factors, some with well established angiogenic functions as well as other more novel factors, can contribute to vascular development and maintenance at the maternal-fetal interface.

CONCLUSIONS

Robust vascular development occurs during implantation and early placentation of normal pregnancies. Studies to define the extent and mechanisms by which defects in vascularity contribute to human implantation failure and early miscarriage need to be undertaken.

Early pregnancy maternal endocrine insulin-like growth factor I programs the placenta for increased functional capacity throughout gestation

In early pregnancy, the concentrations of IGFs increase in maternal blood. Treatment of pregnant guinea pigs with IGFs in early to midpregnancy enhances placental glucose transport and fetal growth and viability near term. In the current study, we determined whether exogenous IGFs altered placental gene expression, transport, and nutrient partitioning during treatment, which may then persist. Guinea pigs were infused with IGF-I, IGF-II (both 1 mg/kg x d) or vehicle sc from d 20-35 of pregnancy and killed on d 35 (term is 70 d) after administration of [(3)H]methyl-D-glucose (MG) and [(14)C]amino-isobutyric acid (AIB). IGF-I increased placental and fetal weights (+15 and +17%, respectively) and MG and AIB uptake by the placenta (+42 and +68%, respectively) and fetus (+59 and +90%, respectively). IGF-I increased placental mRNA expression of the amino acid transporter gene Slc38a2 (+780%) and reduced that of Igf2 (-51%), without altering the glucose transporter Slc2a1 or Vegf and Igf1 genes. There were modest effects of IGF-I treatment on MG and AIB uptake by individual maternal tissues and no effect on plasma glucose, total amino acids, free fatty acids, triglycerides, and cholesterol concentrations. IGF-II treatment of the mother did not alter any maternal, fetal or placental parameter. In conclusion, exogenous IGF-I, but not IGF-II, in early pregnancy increases placental transport of MG and AIB, enhancing midgestational fetal nutrient uptake and growth. This suggests that early pregnancy rises in maternal circulating IGF-I play a major role in regulating placental growth and functional development and thus fetal growth throughout gestation.

Insulin-like growth factor-II regulates the 12-lipoxygenase gene expression and promotes cell proliferation in human keratinocytes via the extracellular regulatory kinase and phosphatidylinositol 3-kinase pathways

To study the relationship between insulin-like growth factor-II (IGF-II) and 12-lipoxygenase (12-LOX) that are upregulated in psoriasis, we monitored 12-lipoxygenase expression in the insulin-like growth factor-II treated human keratinocytes and explored the signaling pathways of 12-lipoxygenase expression. Insulin-like growth factor-II induced 12-lipoxygenase mRNA and protein levels in human keratinocytes through two major signal transduction pathways, namely, the extracellular signaling-regulated kinase (ERK)-mitogen activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways. The IGF-II-induced upregulation of 12-lipoxygenase was attenuated by pretreating the cells with selective inhibitors or by overexpressing dominant-negative MEK. In addition, treatment of HaCaT cells with the 12-lipoxygenase metabolite 12 (S)-hydroxyeicosatetraenoic acid (12(S)-HETE) directly stimulated DNA synthesis and mitogenesis, and injection of insulin-like growth factor-II into the skin of hairless mice induced epidermal hyperplasia. These results suggest that insulin-like growth factor-II is involved in the pathogenesis of psoriasis as a paracrine inducer of 12-lipoxygenase.

Under-expression of VHL and over-expression of HDAC-1, HIF-1?, LL-37, and IAP-2 in affected skin biopsies of patients with psoriasis

BACKGROUND

A feature of psoriasis is the rapid proliferation of keratinocytes, during which apoptosis is blocked and angiogenesis starts. It is known that tumor hypoxic cells produce histone deacetylase-1 (HDAC-1), which up-regulates hypoxia-inducible factor-1alpha (HIF-1alpha) and down-regulates von Hippel-Lindau (VHL) protein by up-regulating vascular endothelial growth factor (VEGF) expression. It has been reported recently that the porcine peptide PR39 (homologous to human LL-37) has angiogenic and antiapoptotic activity. Thus, LL-37, induced by insulin-like growth factor-1 (IGF-1), could help in the production of VEGF. PR39 also induces the expression of inhibitor of apoptosis protein-2 (IAP-2), which blocks apoptosis. The purpose of this work was to analyze whether these genes and their proteins are expressed in psoriatic biopsies.

METHODS

Using semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) messenger RNA (mRNA) expression and immunohistochemical staining, we studied VHL, IAP-2, and related genes in skin biopsies from psoriatic patients and healthy subjects.

RESULTS

An over-expression of the mRNA for HDAC-1, HIF-1alpha, LL-37, and IGF-1 in psoriatic skin, in comparison with skin from healthy subjects, was found. The antiangiogenic VHL mRNA and protein were under-expressed in psoriatic skin and highly expressed in healthy skin. The antiapoptotic IAP-2 was over-expressed in dermal endothelial cells from psoriatic skin. The pro-apoptotic Bax, Fas, and FasL mRNAs were expressed.

CONCLUSIONS

These findings suggest that there could be an association of HDAC-1, HIF-1alpha, LL-37, VHL, and IAP-2 with angiogenic and apoptotic mechanisms in psoriasis.

Altered placental and fetal expression of IGFs and IGF-binding proteins associated with intrauterine growth restriction in fetal sheep during early and mid-pregnancy

The insulin-like growth factors (IGFs) are postulated to be altered in association with the development of intrauterine growth restriction (IUGR). The present studies examined placental and fetal hepatic mRNA concentration of components of the IGF system at two time points (55 and 90 d gestational age, dGA; Term 147 dGA) in a hyperthermia (HT)-induced sheep model of placental insufficiency-IUGR. Maternal plasma insulin and IGF-I were constant at 55 and 90 dGA and were unaffected by treatment. Umbilical vein insulin concentrations tended to be reduced at 90 dGA following HT exposure. Caruncle IGF-I mRNA was increased at 90 dGA in HT placentae (p < 0.05), while cotyledon concentrations were constant over gestation and unaltered by treatment. In control cotyledons, IGF-II mRNA concentration increased (p < 0.01) and IGFBP-3 decreased between 55 and 90 dGA (p < 0.01). Cotyledon IGF-II and caruncle IGFBP-4 mRNA were elevated at 55 dGA in HT placentae compared with control (p < 0.01 and p < 0.05 respectively). Fetal hepatic IGF-I, IGFBP-2, -3 and -4 concentrations rose over gestation (p < 0.05), but there were no treatment effects. These data suggest that changes in placental IGF expression in early and mid gestation may predispose the pregnancy to placental insufficiency, resulting in inadequate substrate supply to the developing fetus later in gestation.

Calcitonin gene-related peptide regulates the expression of vascular endothelial growth factor in human HaCaT keratinocytes by activation of ERK1/2 MAPK

Psoriasis is a chronic disease characterized by abnormal epidermal proliferation, inflammation and angiogenesis. The pathogenetic process resulting in hypervascularity remains to be further investigated. It has been reported that a potent angiogenic factor, vascular endothelial growth factor (VEGF) is overexpressed in psoriatic epidermis and that the level of calcitonin gene-related peptide (CGRP) is elevated in psoriasis lesions and CGRP-containing neuropeptide nerve fibers are denser in the psoriatic epidermis. We hypothesized that CGRP might regulate the expression of VEGF by human keratinocytes. VEGF expression in the CGRP-treated human keratinocytes was investigated and the CGRP signaling pathways were examined with respect to VEGF expression. The mRNA and protein levels of VEGF by CGRP were increased in a concentration-dependent manner. However, this increase was abrogated by pretreatment with an extracellular signal-regulated kinase (ERK) inhibitor PD98059. The CGRP-mediated VEGF induction was also effectively inhibited by a pretreatment with the CGRP receptor antagonist CGRP 8-37. In addition, CGRP treatment induced rapid phosphorylation of ERK1/2, PD98059 and CGRP 8-37 were able to inhibit CGRP-induced ERK1/2 phosphorylation. These results suggest that CGRP regulates the expression of VEGF through the CGRP receptor and ERK1/2 MAPK signaling pathway in human HaCaT keratinocytes.

New light on early post-implantation pregnancy in the mouse: roles for insulin-like growth factor-II (IGF-II)?

Successful placental development and the associated changes to the decidual vasculature during early pregnancy are critical to pregnancy outcome. This study utilised immunohistochemistry to provide a photomicrographic account of trophoblast invasion, as well as the changes in the uterine vasculature in the decidua from days 5.5 to 10.5 of murine pregnancy. The pattern of trophoblast invasion during this time is particularly interesting because, unlike in humans, murine trophoblast giant cells (TGCs) do not invade the endometrium individually but remain in close contact with the expanding giant cell layer. Therefore, trophoblast cells are unlikely to play a direct role in remodelling the maternal vessels in early to mid pregnancy. Nevertheless, the decidual vessels appear to undergo extensive angiogenesis and remodelling to form a network of dilated vessels that presumably maximize placental blood supply. Importantly, the vessels closest to the conceptus lacked a smooth muscle layer throughout early pregnancy and therefore cannot strictly be described as spiral arterioles. TGCs may secrete molecules that can act to induce these vascular changes. Here we show that insulin-like growth factor-II (IGF-II) is expressed throughout early pregnancy in the entire conceptus including trophoblast cells, supporting its role in promoting early placental growth. In addition, the co-localisation of IGF-II and both IGF receptors in the developing blood vessels and/or adjacent stromal cells in the mesometrial, but not in the anti-mesometrial, decidua suggest that IGF-II, upon binding to one of these receptors, may play a role in both decidual angiogenesis and placental differentiation.

All-trans retinoic acid antagonizes UV-induced VEGF production and angiogenesis via the inhibition of ERK activation in human skin keratinocytes

Incident UV radiation leads to the upregulation of vascular endothelial growth factor (VEGF), a potent angiogenic factor, in human skin. However, the molecular basis of UV-induced angiogenesis in skin remains to be elucidated. In this study, we investigated the roles of UV exposure on cutaneous angiogenesis, its associated signaling mechanisms, and the effect of all-trans retinoic acid (tRA) on UV-induced vascularization, and VEGF expression. Using a human epidermal cell line, HaCaT, we found that UV induces VEGF mRNA and protein expression via the MAPK/ERK kinase-ERK1/2 (extracellular signal-regulated kinase 1/2) pathway but not via the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, and that tRA pretreatment significantly inhibits UV-induced VEGF overexpression and ERK1/2 activation. In human skin in vivo, we confirmed that skin vascularization significantly increased after a single exposure to UV, as was evidenced by a prominent increase in vessel size, vascular density, and in the cutaneous area occupied by vessels, and we found that these events are associated with VEGF upregulation. Topical pretreatment with tRA under occlusion inhibited not only UV-induced VEGF upregulation and angiogenesis with a significant reduction of vessel density but also UV-induced ERK1/2 activation in human skin. Collectively, our data demonstrate that tRA inhibits the UV-induced angiogenic switch via downmodulation of ERK1/2 activation and consecutive VEGF overexpression. These findings may help us understand the molecular mechanisms that regulate skin angiogenesis due to UV exposure, and provide evidence of the potential of tRA in terms of preventing angiogenesis-associated skin damage following exposure to UV irradiation.

Vascular endothelial growth factor gene polymorphisms increase the risk to develop psoriasis

We investigated the relationship between eight polymorphisms in the gene encoding for vascular endothelial growth factor (VEGF) (-1540C > A, -1512Ins18, -1451C > T, -460T > C, -160C > T, -152G > A, -116G > A and +405G > C) and plaque-type psoriasis stratified for age at onset, gender and family history of dermatosis. For this purpose, 117 patients with chronic plaque-type psoriasis and 215 healthy subjects were enrolled. We found that being homozygous -1540AA, -1512InsIns, -1451TT, -460CC and -152AA conferred a significant risk in developing psoriasis compared with heterozygous (-1540CA, -1512 + Ins, -1451CT, -460CT and -152AG) and homozygous genotypes (-1540CC, -1512 + +-1451CC, -460TT and -152GG) grouped together [odds ratio (ORs) = 1.73, 1.73, 1.73, 1.77 and 1.87, respectively]. Conversely, having the -116AA or +405GG genotype did not significantly increase the risk of disease expression compared with other genotypes of the same loci. Interestingly, we found that -1540AA, -1512InsIns, -1451TT, -460CC and -152AA homozygous genotypes have a significant two-fold increased risk in developing psoriasis after the age of 40 years (late-onset psoriasis) (ORs = 2.19, 2.19, 2.19, 2.05 and 2.26; P = 0.02, 0.02, 0.02, 0.04 and 0.02, respectively) as compared with controls. On the contrary, we found no phenotype-genotype association of the same magnitude among the patients in whom psoriasis developed at or before the age of 40 years (early-onset psoriasis) compared with controls. Genotype distributions were not significantly different when cases and controls were stratified either by gender or family history of psoriasis. Finally, VEGF plasma concentration was not significantly different between patients and controls and was not correlated with the severity of the disease.