Modulation of renal blood vessel formation by glial cell line-derived neurotrophic factor

Differential Secretion of Angiopoietic Factors and Expression of MicroRNA in Umbilical Cord Blood from Healthy Appropriate-For-Gestational-Age Preterm and Term Newborns-in Search of Biomarkers of Angiogenesis-Related Processes in Preterm Birth

Objectives: Premature birth, defined as less than 37 weeks gestation, affects approximately 12% of all live births around the world. Advances in neonatal care have resulted in the increased survival of infants born prematurely. Although prematurity is a known risk factor for different cardiovascular diseases, little is known about the pathophysiology of vasculature during premature gestation and angiopoietic factors network during premature birth. Aims: The objective of this study was to determine whether the profile of several pro-angiogenic and anti-angiogenic factors in umbilical cord blood (UCB) is different in healthy appropriate-for-gestational-age preterm newborns and normal term babies. The second aim of this study was to investigate the microRNA (miRNAs) expression profile in UCB from preterm labor and to detect miRNAs potentially taking part in control of angogenesis-related processes (Angio-MiRs). Methods: Using an immunobead Luminex assay, we simultaneously measured the concentration of Angiogenin, Angiopoietin-1, FGF-acidic, FGF-basic, PDGF-aa, PlGF, VEGF, VEGF-D, Endostatin, Thrombospondin-2, NGF, BDNF, GDNF, and NT-4 in UCB samples collected from the preterm (n = 27) and term (n = 52) delivery. In addition, the global microRNA expression in peripheral blood mononuclear cells (PBMCs) circulating in such UCB samples was examined in this study using microarray MiRNA technique. Results: The concentrations of five from eight measured pro-angiogenic factors (VEGF, Angiopoietin-1, PDGF-AA, FGF-a, and FGF-b) were significantly lower in UCB from preterm newborns. On the contrary, two angiostatic factors (Endostatin and Thrombospondin-2) were significantly up-regulated in preterm UCB. Among analyzed neurotrophins in preterm newborns, the elevated UCB concentration was found only in the case of GDNF, whereas BDNF was significantly reduced. Moreover, two angiopoietic factors, VEGF-D and PlGF, and two neurotrophins, NT4 and NGF, did not differ in concentration in preterm and term babies. We also discovered that among the significantly down-regulated miRNAs, there were several classical Angio-MiRs (inter alia MiR-125, MiR-126, MiR-145, MiR-150, or MiR155), which are involved in angiogenesis regulation in newborn after preterm delivery. Conclusions: This is the first report of simultaneous measurements of several angiopoietic factors in UCB collected from infants during preterm and term labor. Here, we observed that several pro-angiogenic factors were at lower concentration in UCB collected from preterm newborns than term babies. In contrast, the two measured angiostatic factors, Endostatin and Thrombospondin-2, were significantly higher in UCB from preterm babies. This can suggest that distinct pathophysiological contributions from differentially expressed various angiopoietic factors may determine the clinical outcomes after preterm birth. Especially, our angiogenesis-related molecules analysis indicates that preterm birth of healthy, appropriate-for-gestational-age newborns is an “anti-angiogenic state” that may provide an increased risk for improper development and function of cardiovascular system in the adulthood. This work also contributes to a better understanding of the role of miRNAs potentially involved in angiogenesis control in preterm newborns.

The role of fibromodulin in cancer pathogenesis: implications for diagnosis and therapy

Fibromodulin (FMOD) is known as one of very important extracellular matrix small leucine-rich proteoglycans. This small leucine-rich proteoglycan has critical roles in the extracellular matrix organization and necessary for repairing of tissue in many organs. Given that the major task of FMOD is the modulation of collagen fibrillogenesis. However, recently observed that FMOD plays very important roles in the modulation of a variety of pivotal biological processes including angiogenesis, regulation of TGF-β activity, and differentiation of human fibroblasts into pluripotent cells, inflammatory mechanisms, apoptosis and metastatic related phenotypes. Besides these roles, FMOD has been considered as a new tumor-related antigen in some malignancies such as lymphoma, leukemia, and leiomyoma. Taken together, these findings proposed that FMOD could be introduced as diagnostic and therapeutic biomarkers in treatment of various cancers. Herein, for first time, we highlighted the various roles of FMOD in the cancerous conditions. Moreover, we summarized the diagnostic and therapeutic applications of FMOD in cancer therapy.

Silymarin amplifies apoptosis in ectopic endometrial tissue in rats with endometriosis; implication on growth factor GDNF, ERK1/2 and Bcl-6b expression

The present prospective study was done to evaluate the effect of silymarin (SMN) on endometriotic-like legions establishment and growth in experimentally-induced endometriosis. For this purpose, the experimental endometriosis was induced in 12 rats and then the animals subdivided into endometriosis-sole and SMN (50 mg kg^-1, orally)+endometriosis groups. Following 28 days, the legions establishment, size, Glial cell line-derived neurotrophic factor (GDNF), gfrα1, B Cell Lymphoma 6 (Bcl-6b), Bcl-2, extracellular regulator kinase (ERK1/2) expression ratios, angiogenesis, the apoptosis and fibrosis indices were investigated. The SMN significantly (P < 0.05) decreased the enometriotic-like legions establishment and size, decreased mRNA levels of GDNF, gfrα1, Bcl-6b and Bcl-2 and remarkably diminished GDNF, gfrα1, Bcl-6b and Bcl-2-positive cells distribution/mm² of tissue versus endometriosis-sole group. The SMN + endometriosis group exhibited a significant (P < 0.05) enhancement in ERK1/2 expression and represented diminished vascularized area and increased apoptosis and fibrosis indices, as well. In conclusion, the SMN by down-regulating GDNF and its receptor gfrα1 expression inhibits GDNF-gfrα1 complex generation and consequently suppresses Bcl-6b expression. Moreover, the SMN by enhancing the ERK1/2 expression and by suppressing the Bcl-2 expression promotes the apoptosis pathway. Finally, the SMN by down-regulating the angiogenesis ratio accelerates apoptosis and consequently induces severe fibrosis in endometriotic-like legions.

Glial Cell Line-Derived Neurotrophic Factor (GDNF) Promotes Angiogenesis through the Demethylation of the Fibromodulin (FMOD) Promoter in Glioblastoma

Background

Angiogenesis plays an important role in the progression of glioblastoma, with a high degree of malignancy. Previous studies have proved that glial cell line-derived neurotrophic factor (GDNF) and fibromodulin (FMOD) are strongly expressed in human glioblastoma. The purpose of this study was to explore the roles of GDNF and FMOD in angiogenesis and the molecular mechanisms underlying these roles in human glioblastoma.

Material/Methods

The effects of GDNF on the expression and secretion of vascular endothelial growth factor (VEGF) in human glioblastoma cell line U251 and angiogenesis in human umbilical vein endothelial cells (HUVECs) were investigated. The molecular mechanism of GDNF-induced expression of FMOD was explored. The roles of FMOD in GDNF-induced expression and secretion of VEGF and angiogenesis were also examined.

Results

In the present study, we showed that GDNF promoted the expression and secretion of VEGF in U251 cells. VEGF mediated GDNF-induced angiogenesis in human glioblastoma. In addition, GDNF significantly upregulated the expression of FMOD in U251 cells. Mechanistically, the results of luciferase reporter assay and methylation-specific PCR (MSP) demonstrated that GDNF facilitated the demethylation of the FMOD promoter. More importantly, we found that FMOD acted as an important mediator in VEGF expression and angiogenesis induced by GDNF in human glioblastoma.

Conclusions

Collectively, our data show that GDNF promotes angiogenesis through demethylation of the FMOD promoter in human glioblastoma, indicating that GDNF and FMOD may be potential therapeutic targets for glioblastoma.

GDNF secreted from adipose-derived stem cells stimulates VEGF-independent angiogenesis

Adipose tissue stroma contains a population of mesenchymal stem cells (MSC) promote new blood vessel formation and stabilization. These adipose-derived stem cells (ASC) promote de novo formation of vascular structures in vitro. We investigated the angiogenic factors secreted by ASC and discovered that glial-derived neurotrophic factor (GDNF) is a key mediator for endothelial cell network formation. It was found that both GDNF alone or present in ASC-conditioned medium (ASC-CM) stimulated capillary network formation by using human umbilical vein endothelial cells (HUVECs) and such an effect was totally independent of vascular endothelial growth factor (VEGF) activity. Additionally, we showed stimulation of capillary network formation by GDNF, but not VEGF, could be blocked by the Ret (rearranged during transfection) receptor antagonist RPI-1, a GDNF signaling inhibitor. Furthermore, GDNF were found to be overexpressed in cancer cells that were resistant to the anti-angiogenic treatment using the VEGF antibody. Cancer cells in the liver hepatocellular carcinoma (HCC), a non-nervous related cancer, highly overexpressed GDNF as compared to normal liver cells. Our data strongly suggest that, in addition to VEGF, GDNF secreted by ASC and HCC cells, may be another important factor promoting pathological neovascularization. Thus, GDNF may be a potential therapeutic target for HCC and obesity treatments.

Bridging the gap between traditional cell cultures and bioreactors applied in regenerative medicine: practical experiences with the MINUSHEET perfusion culture system

To meet specific requirements of developing tissues urgently needed in tissue engineering, biomaterial research and drug toxicity testing, a versatile perfusion culture system was developed. First an individual biomaterial is selected and then mounted in a MINUSHEET(®) tissue carrier. After sterilization the assembly is transferred by fine forceps to a 24 well culture plate for seeding cells or mounting tissue on it. To support spatial (3D) development a carrier can be placed in various types of perfusion culture containers. In the basic version a constant flow of culture medium provides contained tissue with always fresh nutrition and respiratory gas. For example, epithelia can be transferred to a gradient container, where they are exposed to different fluids at the luminal and basal side. To observe development of tissue under the microscope, in a different type of container a transparent lid and base are integrated. Finally, stem/progenitor cells are incubated in a container filled by an artificial interstitium to support spatial development. In the past years the described system was applied in numerous own and external investigations. To present an actual overview of resulting experimental data, the present paper was written.

Supportive development of functional tissues for biomedical research using the MINUSHEET® perfusion system

Functional tissues generated under in vitro conditions are urgently needed in biomedical research. However, the engineering of tissues is rather difficult, since their development is influenced by numerous parameters. In consequence, a versatile culture system was developed to respond the unmet needs.

Optimal adhesion for cells in this system is reached by the selection of individual biomaterials. To protect cells during handling and culture, the biomaterial is mounted onto a MINUSHEET® tissue carrier. While adherence of cells takes place in the static environment of a 24 well culture plate, generation of tissues is accomplished in one of several available perfusion culture containers. In the basic version a continuous flow of always fresh culture medium is provided to the developing tissue. In a gradient perfusion culture container epithelia are exposed to different fluids at the luminal and basal sides. Another special container with a transparent lid and base enables microscopic visualization of ongoing tissue development. A further container exhibits a flexible silicone lid to apply force onto the developing tissue thereby mimicking mechanical load that is required for developing connective and muscular tissue. Finally, stem/progenitor cells are kept at the interface of an artificial polyester interstitium within a perfusion culture container offering for example an optimal environment for the spatial development of renal tubules.

The system presented here was evaluated by various research groups. As a result a variety of publications including most interesting applications were published. In the present paper these data were reviewed and analyzed. All of the results point out that the cell biological profile of engineered tissues can be strongly improved, when the introduced perfusion culture technique is applied in combination with specific biomaterials supporting primary adhesion of cells.

Development of renin expression in the mouse kidney

During metanephric kidney development, renin is expressed in the walls of larger intrarenal arteries, but is restricted to the terminal part of the preglomerular arterioles in the adult kidney. Our study describes the three-dimensional development of renin expression in mouse kidneys during fetal and postnatal life. Renin immunoreactivity first appeared at day 14 of development in the cells expressing alpha-smooth muscle actin (alphaSMA) in the arcuate arteries. Before adulthood, the branching of the arcuate arterial tree increased exponentially and renin expression shifted from proximal to distal parts of the tree. Renin expression at branching points or in the cones of growing vessels was not seen. Instead, renin expression appeared after vessel walls and branches were already established, disappeared a few days later, and remained only in the juxtaglomerular regions of afferent arterioles. In these arterioles, coexpression of renin and alphaSMA disappeared gradually, with the terminal cells expressing only renin. At all stages of kidney development, renin expression among comparable vessel segments was heterogeneous. Renin expression remained stable after it reached the terminal parts of afferent arterioles.

Adenovirus-mediated overexpression of a gene prevents hearing loss and progressive inner hair cell loss after transient cochlear ischemia in gerbils

The use of adenoviral vectors has recently provided a novel strategy for direct gene transfer into the cochlea. In this study, we assessed the utility of an adenoviral vector expressing glial-cell-derived neurotrophic factor (GDNF) in ischemia-reperfusion injury of the gerbil cochlea. The vector was injected through the round window 4 days before ischemic insult. The distribution of a reporter transgene was confirmed throughout the cochlea from the basal to the apical turn and Western blot analysis indicated significant upregulation of GDNF protein 11 days following virus inoculation. Hearing ability was assessed by sequentially recording compound action potentials (CAP), and the degree of hair cell loss in the organ of Corti was evaluated in specimens stained with rhodamine-phalloidin and Hoechst 33342. On the seventh day of ischemia, the CAP threshold shift and inner hair cell loss were remarkably suppressed in the Ad-GDNF group compared with the control group. These results suggest that adenovirus-mediated overexpression of GDNF is useful for protection against hair cell damage, which otherwise eventually occurs after transient ischemia of the cochlea.

Biosensor-controlled perfusion culture to estimate the viability of cells

A perfusion cell culture is characterised by the continuous addition of fresh nutrient medium and the withdrawal of an equal volume of used medium, allowing the realisation of cell cultivation conditions that are approximated as closely as possible to the in vivo situation. The combination of a perfusion cell culture with an enzyme glucose biosensor allows the glucose consumption of the cell culture to be monitored continuously. The resulting biosensor-controlled perfusion cell culture is a complex biomonitoring system that is useful for checking the metabolic state of a perfusion cell culture continuously and non-invasively over several days. With this experimental setup, it has been possible to test detrimental external effects on living systems at early stages, in vitro, but under in vivo-like conditions.