PERIPHERAL BLOOD a SIMPLE CELL SOURCE FOR THE GENERATION OF ANGIOGENIC PROGENITORS FROM MONOCYTES

PERIPHERAL BLOOD: A SIMPLE CELL SOURCE FOR THE GENERATION OF ANGIOGENIC PROGENITORS FROM MONOCYTES ANNA MARIA BLOCKI (B.SC. UNIVERSITY OF APPLIED SCIENCES OF GELSENKIRCHEN) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY NUS GRADUATE SCHOOL FOR INTEGRATIVE SCIENCES AND ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2012 Declaration I hereby declare that the thesis is my original work and that it has been written by me in its entirety. To the best of my knowledge, I have duly referenced the sources of information and duly acknowledged the origin of other materials used in this thesis. This thesis has not been submitted for any degree in any university previously. ___________________________---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------_ Anna Blocki 26 December 2012 II Acknowledgements I would like to thank my supervisor, A/P Michael Raghunath, who introduced me to the art of research. He introduced the lab to me as a huge playground, which I could use to live my curiosity. I am glad that he left me the freedom to try out various ideas and that he supported and mentored me on the way. His excitement about the sometimes surprising results was infectious and his encouragement when I couldn’t see the light at the end of the tunnel helped me to enjoy the journey of my PhD. His support to make research happen much beyond the intellectual discussion ensured that we were able to get this far. I am thankful for the support from my colleagues in the Tissue Modulation Laboratory, especially from Yingting Wang, who joined my research project during my last year and helped to generate beautiful data. Her enthusiasm, positive and always smiling nature and will to achieve as much as she can, made working with her a joy. Maria Koch from the University of Applied Sciences in Bremen, who joined our lab just recently as an international student further added a fantastic character to our team and managed to produce an astonishing amount of data. Although not yet through with her undergraduate studies, it is obvious that she will be a great and passionate researcher. I hope I will be able to work with both of them in the future. I am grateful for the support and advice from Prof Herbert Schwarz, who introduced me into the fabulous research of immunology and helped to look into my research from a different angle. I would also like to thank Prof Kishore Bhakoo, who always asked critical questions and gave valuable feedback. He also provided the means of life-cell imaging and in vivo studies. At this point I also have to thank Shebbrin Shehzahdi, who is an experienced research assistant of Prof Bhakoo and conducted the in vivo experiments with me. I learned a lot from her. A very special thank you and an “I couldn’t have done it without you” have to be said to my husband Sebastian Beyer. He made me dream of a fabulous adventure in Asia and a unique life that would be satisfying personally and professionally. He always believed in me and I taught me to believe in myself and to reach for the stars. It was indispensable for me to have someone, I could share all the happy and frustrating moments and especially to ramble about my work, when it did not let me go. Besides the mental support Sebastian was a person who intellectually and physically helped me to my work. It makes oneself stronger to know that there is someone you can always count on. My parents and grandparents brought me up in a way that taught me to always work hard and play fair and never be satisfied with an outcome if I haven’t tried as hard as I could. Their pride of me through my whole life, their love and encouragement provided me with the safety that I could not disappoint them and would have always a family to turn to. I wouldn’t have brought up the courage to go the way I did without their support. I owe my little siblings and my close friends a very special thank you, because they always showed understanding and did not let me go despite the great geographical distance. It is good to know that I have a special place in their hearts and they have a special place in mine. II Table of Content Acknowledgements    I   Summary    V   List of Illustrations    VII   List of Tables    VII   List of Figures    VIII   List of abbreviations   .  IX   Chapter : Pericytes, more than just MSCs? A functional in vitro study of pericytes and bone marrow MSCs in angiogenesis    1   Scope of Chapter   .  1   Identification of pericytes   .  2   Pericyte  recruitment  and  function  during  development   .  2   Pericyte  recruitment  and  function  in  induced  angiogenesis   .  5   Origin  of  pericytes  in  induced  angiogenesis    6   Pericytes are a population of mesenchymal stem cells    7   Goals  and  Objectives    10   Results    11   Pericytes shared tested flow cytometry marker profile with bone marrow (bm) MSCs   .  11   Pericytes and bmMSCs but not fibroblasts differentiate into both mesenchymal lineages: osteoblasts and adipocytes   .  13   BmMSCs and fibroblasts not share the expression of NG2, desmin and Tie-2 with pericytes   .  14   Co-localisation with the endothelial network on matrigel is not a pericyte-specific behaviour   .  16   Pericytes contribute to the formation of cord structures in a monolayer co-culture   .  24   Discussion   .  27   Conclusion    29   Materials and Methods    31   Cell culture    31   Flow cytometry    31   Immunocytochemistry   .  32   Differentiation into adipocytes and osteoblasts    33   Life cell labelling    34   Tube formation assay on matrigel   .  34   Spheroid sprouting assay    34   2D cord formation assay   .  35   Statistical analysis   .  35   Chapter : Blood-derived angiogenic cells (BDAC) represent a pericytic population and enhance early stages of angiogenesis.    36   Scope of chapter   .  36   Introduction   .  37   Not all pericytes are MSCs    37   Formulation of hypothesis   .  38   Monocytes/macrophages  during  angiogenesis   .  39   Macrophage in the initial formation of vasculature during development    40   Macrophages in induced angiogenesis   .  42   Other non-conventional monocyte-derived cells generated in vitro    44   Fibrocytes and fibrocyte-like cells    45   Endothelial progenitor cells   .  48   Goals  and  objectives    50   Results   .  51   III Generation of spindle-shaped cells in large numbers in the presence of macromolecules   .  51   Spindle-shaped cells express pericyte markers   .  56   Spindle-shaped cells express markers related to angiogenesis    59   BDAC express a unique marker profile    60   BDAC are distinguishable from blood-derived fibrocytes and endothelial progenitors   .  61   BDAC are not a multipotent cell population   .  64   BDAC are distinguishable from classical M1 and M2 macrophages in vitro    65   BDAC co-localise with and stabilise endothelial networks on matrigel.   .  67   BDAC contribute and enhance endothelial sprouting in vitro   .  71   BDAC have a pro-angiogenic secretion profile and actively support endothelial sprouting via MMP secretion.    74   BDAC are pro-angiogenic in vivo   .  79   Discussion   .  86   BDAC represent a unique monocyte-derived cell population, which has pericyte characteristics and can be generated in clinically relevant numbers from peripheral blood.   .  86   BDAC exhibit a pericytic functional behaviour and are pro-angiogenic in vitro and in vivo   .  90   BDAC have a pro-angiogenic secretion profile and actively support endothelial sprouting via MMP9 secretion.    91   Conclusion    94   Future work   .  95   Materials and Methods    97   Cell culture    97   Generation of blood derived angiogenic cells (BDAC)   .  97   Study of the uptake of macromolecules by PBMC    98   Flow cytometry    98   Immunocytochemistry   .  98   Adherent cytometry to assess number of adherent cells after days (count of DAPI stained nuclei)    99   Differentiation into adipocytes and osteoblasts    99   RT-PCR    99   Induction of collagen I secretion and SDS-Page of pepsin digested culture    100   Life cell labelling   .  100   Tube formation assay on matrigel    100   Spheroid sprouting assay and inhibition of MMP9    100   Zymography   .  101   Angiogenesis proteome array    102   In vivo tumour model    102   Statistical analysis    103   References    104   Appendix: List of selected publications & academic contributions   .  113   Successful acquisition of research funding   .  113   Patents    113   Research articles   .  113   Conference Contributions   .  113   IV Summary Currently pericytes are considered to represent mesenchymal stem cells (MSCs) in a perivascular niche and can be recruited from bone marrow (bm). However literature in the past often suggested pericytes to express hematopoietic markers, when pericytes were studied at early stages of angiogenesis. MSCs lack hematopoietic and monocytic markers by definition. Therefore the discrepancy in marker expression of pericytes pointed to the notion that more than one pericyte population exists. “Early” pericytes would be hematopoietic and support early stages of angiogenesis. “Late” pericytes would be MSCs and recruited to forming vessels at later stages of angiogenesis, where they would stabilize and support maturation of formed vessels. We generated a novel, spindle-shaped, adherent cell type from human peripheral blood, which expressed besides hematopoietic markers CD45 and CD11b, pericyte-related markers PDGFR-β, NG2 and desmin. Therefore the generated cells could resemble the hematopoietic pericyte population, which was only studied in vivo so far. However, pericytes are an elusive cell type and so far there is no established knowledge on how to identify pericytes in vitro. Therefore we studied available pericytes derived from the placenta. We used this cell type to establish a pericyte specific marker expression and in vitro functional profile. Recently pericytes were isolated systematically from various tissues and were shown to be MSCs. In the scientific field the question arose if all MSCs might act as pericytes. Therefore we compared pericytes with bmMSCs and fibroblasts. We identified markers NG2, desmin and Tie-2 to distinguish pericytes from other stromal cells and demonstrated that only pericytes enhanced sprouting and sprout integrity in a spheroid sprouting assay. Further only pericytes contributed to cord formation with endothelial cells (EC) in a monolayer. We propose that pericytes are a subpopulation of MSCs, with specialised functions in blood V vessel biology that are not inherent to all MSCs. Thereby we also identified markers and functional behaviour in vitro to identify pericytes and distinguish it from other cell types. We then subjected the adherent spindle-shaped cells derived from human peripheral blood to the same assays. We showed that the generated cells co-localised with and stabilised endothelial networks on matrigel. Further we have shown that they enhance endothelial sprouting in vitro. The subcutaneous co-injection of generated cells with U87 glioma cells resulted in larger tumours with higher vasculature density. As the generated cells behaved strongly pro-angiogenic in vitro and in vivo we named them blood-derived angiogenic cells (BDAC). The pro-angiogenic secretion profile of BDAC indicated a role of BDAC in the support of endothelial migration, proliferation and sprouting. MMP9, secreted by BDAC, was proven to be a main driver thereof. In conclusion we developed a biotechnological platform to generate functional angiogenic cells from peripheral blood in clinically relevant numbers. This opens avenues for generating patient-specific cells from an easy accessible and renewable cell source for cell-based treatment of ischemic diseases. Further BDAC resemble a haematopoietic pericytic population described only in vivo so far. Therefore this will allow a more detailed study of these cells and their role in angiogenesis in vitro. VI List of Illustrations Illustration 2-1: Illustration of working hypothesis. . 39 Illustration 2-2: Molecular structure of MMP9/13 inhibitor. 101 List of Tables Table 1-1: Antibodies used for flow cytometry 32 Table 1-2: Antibodies used for immunocytochemistry . 33 Table 2-1: Angiogenic functions of the secreted factors by BDAC. 91 Table 2-2: Antibodies used for flow cytometry 98 Table 2-3: Antibodies used for immunocytochemistry . 98 VII List of Figures Figure 1-1: Pericytes have a MSC-related marker profile. . 11 Figure 1-2: Fibroblast share pericyte and bmMSC marker profile . 12 Figure 1-3: Pericyte and bmMSCs show a multipotent differentiation potential, which is not shared by fibroblasts. . 13 Figure 1-4: Pericyte marker NG2 and desmin are not shared by bmMSCs and fibroblast. 15 Figure 1-5: Tubular network formation is endothelial cell specific. . 16 Figure 1-6: Co-localisation with endothelial tubular network is not pericytic-specific 17 Figure 1-7: Only pericytes maintained endothelial network. 18 Figure 1-8: Only pericytes maintained endothelial network over a course of 24h. 19 Figure 1-9: Pericytes are able to significantly maintain endothelial tubular networks on matrigel. 20 Figure 1-10: Sprouting in an in vitro spheroid-sprouting assay is endothelial cell specific. 21 Figure 1-11: Pericytes enhance sprouting in an in vitro spheroid sprouting assay. 22 Figure 1-12: Only pericytes co-localise with formed sprouts. 23 Figure 1-13: Cord structures of pericytes and EC formed in monolayer co-cultures. 25 Figure 2-1: PBMC take up ficoll macromolecules of various macromolecular weights 52 Figure 2-2: Granulocytes and lymphocytes are the main fractions of PBMC to take up ficoll macromolecules . 53 Figure 2-3: Adherent spindle-shaped cells can be generated from PBMC in the presence of ficoll macromolecules . 55 Figure 2-4: BDAC express established pericyte markers. 57 Figure 2-5: BDAC express angiogenesis-related markers. . 59 Figure 2-6: BDAC express a marker profile not shared by other cells. 60 Figure 2-7: BDAC not express vWF or collagen I. . 62 Figure 2-8: BDAC not differentiate into osteoblasts or adipocytes. 64 Figure 2-9: BDAC are distinguishable from classical M1 and M2 macrophages and cannot be polarised. . 66 Figure 2-10: BDAC co-localise with endothelial tubular network on matrigel. . 68 Figure 2-11: BDAC co-localise with junction points of the endothelial tubular network. . 69 Figure 2-12: BDAC co-localise with the endothelial tubular network also in poor culture medium. 70 Figure 2-13: BDAC stabilise endothelial tubular network on matrigel 70 Figure 2-14: BDAC contribute to endothelial sprouting in vitro. . 71 Figure 2-15: BDAC enhance endothelial sprouting in vitro. 73 Figure 2-16: BDAC secrete a proangiogenic marker profile. . 75 Figure 2-17: BDAC secrete MMP9, which digests gelatine and collagen I in a zymograph. 76 Figure 2-18: MMP inhibition decreases sprouting efficiency only in EC -BDAC co-cultures. . 78 Figure 2-19: Solid glioma tumour has a larger size and weight, when co-injected with BDAC. . 80 Figure 2-20 : Co-injection of U87 and BDAC results in more microvasculature. . 81 Figure 2-21: Solid tumours, which result from co-injection of U87 cells with BDAC, possess a higher vascular density. 82 Figure 2-22: Only in solid tumours, which resulted from the co-injection of U87 cells with BDAC, mature larger vessels were observed. 84 VIII Study of the uptake of macromolecules by PBMC PBMCs were isolated as described above and seeded in LG DMEM (without phenol-red) containing either FITC-tagged Fc70 or Fc400 on non-adherent dishes for hour. Afterwards cells were collected and fixed in 1% formaldehyde for 15 minutes. Fixed cells were analysed either using the Cyan flow cytometer (Dako Cytomation) or resuspended in PBS buffer supplemented with 0.5 % FBS for further staining. Cells nuclei were stained with DAPI and the cytoskeleton with 594-labelled Phalloidin for 30 minutes. Cells were washed once with PBS buffer supplemented with 0.5 % FBS and resuspended in PBS. Cells were then distributed between two coverslips and viewed with a Zeiss apotome fluorescence microscope. Flow cytometry Flow cytometry was performed as explained in chapter 1. Antibodies used and not mentioned in chapter can be found in table 2-2. Antigen CD206 Cat No. Isotype Volume per 50µL Source 551135 Control FITC Mouse IgG1, κ 10 µL BD Pharmingen Table 2-2: Antibodies used for flow cytometry Immunocytochemistry BDAC were generated and methanol-fixed on day 5. Immunocytochemistry was performed as described in chapter 1. Antibodies used and not mentioned in chapter can be found in table 2-3. Antigen Cat No. VEGFR-1 (Flt-1) CD31 (PECAM-1) vWF PM-2K CD31 VE-cadherin ab32152 M0823 A0082 ab58822 ab28364 ab33168 Format Primary Antibodies Rabbit monoclonal Mouse monoclonal Rabbit polyclonal antiserum Mouse monoclonal Rabbit polyclonal Rabbit polyclonal Dilution Source :100 1:50 1:1000 1:1000 1:50 1:50 Abcam Dako Cytomation Dako Cytomation Abcam Abcam Abcam Table 2-3: Antibodies used for immunocytochemistry 98 Adherent cytometry to assess number of adherent cells after days (count of DAPI stained nuclei) Adherent fluorescent cytometry was based on a montage of sites per well taken by a coolSNAP HQ camera attached to a Nikon TE2000 microscope at 2x magnification, covering 83% of total well area. DAPI fluorescence was accessed with a single Dapi filter [Ex 350nm/Em 465nm]. The number of stained nuclei was imported into Microsoft Excel, and the mean ± SD of the areas was calculated. Differentiation into adipocytes and osteoblasts BDAC were induced using protocols described in chapter 1. RT-PCR Total RNA was extracted using the RNAeasy single step column spin (Qiagen) following the manufacturer’s protocol. Isolated mRNA concentrations were measured using Nanodrop and cDNA was synthesised from equal amounts of isolated mRNA using Superscript reverse transcriptase II. RT-PCR reactions were performed using following primers: collagen forward primer 5’ agccagcagatcgagaacat 3’, reverse primer 5’ cttgtccttggggtcttg 3’; vWF forward primer 5’taagtctgaagtagaggtgg 3’, reverse primer 5’ agagcagcaggagcactggt 3’. RT-PCR was monitored on a Stratagene real-time PCR instrument (Stratagene) with a PCR master mix based on Platinum Taq DNA polymerase (Invitrogen). Data analysis was performed using the MxPro software (Stratagene). For each cDNA sample, the Ct value was defined as the cycle number at which the fluorescence intensity reached the amplification based-threshold fixed by the instrument-software. Relative expression level for collagen I and vWF were calculated by normalising the quantified cDNA transcript level (Ct) to that of GAPDH. Fold-change of mRNA levels between samples was calculated as Ct1-Ct2. 99 Induction of collagen I secretion and SDS-Page of pepsin digested culture Collagen secretion into culture media was induced by supplementing the culture media with 100 mM L-ascorbic acid phosphate (Wako Pure Chemical Industries, Osaka, Japan). After days culture media were harvested into separate vials, culture medium was digested with porcine gastric mucosa pepsin (2500 U/mg; Roche Diagnostics Asia Pacific, Singapore) in a final concentration of 100 mg/mL. Samples were incubated at room temperature (RT) for 2h with gentle shaking followed by neutralisation with 0.1 N NaOH. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE): Medium and cell layer samples were analysed by SDS- PAGE with 5% acrylamide under non-reducing conditions. A small format was used (Mini-Protean 3; Bio-Rad Laboratories, Singapore). Protein bands were stained with the SilverQuestÔ kit (Invitrogen) according to the manufacturer’s protocol. Densitometric analysis of wet gels was performed on the GS-800Ô Calibrated Densitometer (Bio-Rad) with Quantity One v4.5.2 analysis software (Bio-Rad). Life cell labelling BDAC were labeled using the protocol mentioned in chapter 1. Tube formation assay on matrigel Tube formation assay was performed as described in chapter 1. HUVEC were co-cultured with BDAC on matrigel at a ratio of 2:1. Quantification of total tube length per taken area was done with the Fiji software using the simple neurite tracer plugin. Spheroid sprouting assay and inhibition of MMP9 Spheroid sprouting assay was performed as described in chapter 1. BDAC were either added to EC (HUVEC) to form spheroids at a ratio of 1:2 or as single cells at indicated cell concentration to the spheroid suspensions in EGM-2 with µg/ml methylcellulose. For 100 MMP9 inhibition MMP9/13 inhibitor (Santa Cruz, sc-311438, Ill. 2-2) was resuspended in DMSO to yield a stock concentration of 20.2 mM. MMP9/13 inhibitor was added at a final concentration of µM to the spheroid suspensions in EGM-2 with µg/ml methylcellulose. The MMP9/13 inhibitor is a piperazine-based, cell-permeable, and highly potent inhibitor of MMP-9 (IC50 = 900 pM) and MMP-13 (IC50 = 900 pM). It was reported to inhibit MMP-1 and MMP-3 at much higher concentrations (IC50 = 43 nM and 23 nM, respectively) and also acted as an inhibitor of MMP-7 (IC50 = 930 nM). Cumulative sprout length was measured with the Fiji software. Illustration 2-2: Molecular structure of MMP9/13 inhibitor. Zymography Zymograph SDS-PAGE gels composed of 10% acrylamide gel containing 1mg/ml gelatin or neutralised collagen I and of a stacking gel containing 3% acrylamide. Volumes of 20 µl of sample were loaded into each well of the gel and proteins in the samples were separated on the gel by SDS-PAGE. Zymographs were washed with buffer containing 2.5% TritonX100, 50 mM Tris, 5mM CaCl2 and 1µM ZnCl2 that allowed the MMPs, which were separated by their size to re-nature, for hour. Afterwards zymographs were rinsed with deionised H2O and incubated in a reaction buffer containing 50 mM Tris, mM CaCl2 and µM ZnCl2 at 37°C with gentle agitation over night. Zymographs were stained with Page Blue using manufacturer’s protocol. Briefly zymographs were rinsed with deionised H2O twice, 101 incubated for hour with the staining solution and washed more times with deionised H2O. Densitometric analysis of wet gels was performed on the GS-800Ô Calibrated Densitometer (Bio-Rad) with the Quantity One v4.5.2 image analysis software (Bio-Rad). Angiogenesis proteome array BDAC were incubated with LG DMEM containing 0.5% FBS for days. Media was collected and un-conditioned media as a control were filtered through a 0.22 µm pore-size filter. Secretion profile of BDAC was established using an angiogenesis proteome array from (R&D) (Cat. no. ARY007) following the manufacturers protocol. Captured antigens were visualised using a chemiluminescence substrate from Pierce (femto) and a Versadoc (Biorad). In vivo tumour model 2.5 million U87-MG cells were mixed alone or together with million BDAC in 200 µl of L15 media and added to concentrated matrigel at a v/v ratio 1:1. Nude mice were anesthetised using isoflurane. Cell suspensions (200 µl containing million U87 and 0.5 million BDAC) were injected subcutaneously into the flanks of the mice. U87-MG cells alone were injected on the left and U87-MG cells with BDAC on the right. After tumours had reached a critical size mice were sacrificed and tumours harvested. Tumours were snap-frozen in liquid nitrogen and stored at -80°C. Samples were embedded in OCT medium and cryosectioned at a thickness of µm. Cryosections were fixed in ice-cold 100% methanol and air-dried. Sections were blocked with 3% BSA in PBS for hour and incubated with rabbit polyclonal antibodies against CD31, VE-cadherin or vWF diluted in PBS (table 2-3) for 1.5 hours. Slides were washed times with PBS for 10 minutes in coblin jars and then incubated with secondary antibodies and DAPI for 30 minutes. washes of the slides with PBS were repeated and sections were mounted. Sections were viewed using an epifluorescence microscope (Olympus, IX71) or an Apotome (Zeiss). 102 Statistical analysis Obtained values were averaged and are displayed as average value +/- standard deviation. 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 112 Appendix: List of selected publications & academic contributions Successful acquisition of research funding ING09006, Singapore MIT alliance for research and technology 49,800 S$ - official collaborator ING11024-BIO, Singapore MIT alliance for research and technology 89,600 S$ - official collaborator Patents 1. WO2011108993 (A1) Culture Additives to boost stem cell proliferation and differentiation response, M. Raghunath, F. Loe, A. Blocki, Y. Peng 2. PCT filing number SG2012/000083, Pericyte Progenitors from Peripheral Blood, M. Raghunath, A. Blocki Research articles 1. Applying macromolecular crowding to enhance extracellular matrix deposition and its remodeling in vitro for tissue engineering and cell-based therapies, Chen, C.; Loe, F.; Blocki, A.; Peng, Y.; Raghunath, M.; ADVANCED DRUG DELIVERY REVIEWS, 63, 4-5, pp 277-290, 2011. 2. Assembly of biomacromolecule loaded polyelectrolyte multilayer capsules by using water soluble sacrificial templates. Sebastian Beyer, Jianhao Bai , Anna M. Blocki , Chaitanya Kantak , Qianru Xue , Michael Raghunath and Dieter Trau ; Soft Matter, 2012,8, 2760-276. Conference Contributions Talks 1. Dirty Surface - Cleaner Cells? Some Observations with a Bio-Assembled Extracellular Matrix; Loe, F. C.; Peng, Y.; Blocki, A.; Thomson, A.; Lareu, R. R.; Raghunath, M.; 13TH INTERNATIONAL CONFERENCE ON BIOMEDICAL ENGINEERING, VOLS 1-3, IFMBE Proceedings , 23, 1-3,1469-1472, 2009 2. A novel approach to derive pericyte progenitors from peripheral blood, Anna Blocki, Kishore Bhakoo, Michael Raghunath, TERMIS AP meeting August 2011, Singapore, Singapore Posters 1. Generating Multipotent Fibrocytes from Peripheral Blood under Macromolecular Crowding, Anna Blocki, Michael Raghunath, TERMIS EU meeting June 2010 in Galway, Ireland 2. Lipid core alginate shell microparticles for tissue engineering; Beyer S.; Blocki A.; Bai J.; Raghunath M.; Trau D.; Poster Presentation at TERMIS EU meeting June 2010 in Galway, Ireland. 3. A Novel Approach to Generate Pericyte Precursors From Peripheral Blood, Anna Blocki, Michael Raghunath, Regenerative medicine-innovation for clinical therapies symposium March 2011, Hilton Head, USA 4. A Novel Approach to Generate Pericyte Progenitors from Peripheral Blood, Anna Blocki, Yingting Wang, Kishore Bhakoo, Michael Raghunath, Keystone symposium: Angiogenesis: Advances in Basic Science and Therapeutic Applications, January 2012, Snowbird Utah, USA     113 [...]... like anaemia, thrombocythemia, enlarged and deformed hearts and reduced size of livers and kidneys (Leveen et al 1994) Large blood vessels like the aorta were dilated (almost double the diameter) with a thinner layer of smooth muscle cells (SMC), the perivascular cells found around large blood vessels As the number of SMC remained the same as in control groups the thinning of the muscular layer was thought... which are commercially available, were compared in their marker expression and functional behaviour in various angiogenic in vitro assays We aimed to establish a platform to identify and characterise pericytes in vitro with easily accessible cell sources By this means we hope to establish a standard for pericyte identification, which due to the availability of cells and other resources can be used by other... et al 2012) The current results clearly indicate that at least a subset of pericytes originates from the bone marrow in induced angiogenesis What ratio of pericytes is recruited from the bone marrow to the angiogenic side will depend on the nature of the tumour or wound (Lamagna et al 2006) Pericytes are a population of mesenchymal stem cells Bone marrow is a source of MSCs The minimal criteria of. .. potential pericyte populations and other angiogenic cells Ms Yingting Wang, a master student, who joined the project under my supervision during the last year helped with the conduction of some of the experiments Together we established the marker profile and she performed the majority tube formation assays on matrigel The raw data were analysed and compiled by myself A manuscript that comprises of these... tumour associated macrophage basic fibroblast growth factor transforming growth factor β urokinase plasminogen activator matrix metallo protease Tie-2 expressing macrophage mesenchymal progenitor cells peripheral blood mononuclear cells endothelial progenitor cells granulocyte/macrophage-colony stimulating factor outgrowth endothelial cells endothelial like cells endothelial nitric oxide synthase ficoll... the stretched vessel diameter There was no sign of underdevelopment or degeneration of the blood vessels As SMC are located 2 around blood vessels it was suggested that PDGF-B was not responsible for the recruitment or proliferation of SMC, but rather for the modulation of cellular functions like cellular contraction, which is necessary for vascular wall integrity Interestingly, elastic membranes and... which are the networks of capillaries in the kidney, lacked mesangial cells, the specialized pericytes in the kidney, leading to leakage of glomeruli The cause of haemorrhages was then determined to be the lack of pericytes in various tissues like brain, lung, heart and adipose tissue in PDGF-B knockout mice (Lindahl et al 1997) PDGFR-β positive cells were found in the wall of large blood vessels such as... to a marker expression analysis Figure 1-1: Pericytes have a MSC-related marker profile Pericytes derived from the placenta and bmMSCs were grown in triplicates in separate flasks for one passage until confluency and were stained for MSC, EC and hematopoietic markers and analysed via flow cytometry Full graphs represent the isotype control, whereas checked graphs represent the stained sample Data are... disintegrated slowly as evident by the appearance of single cells, which were not incorporated into the network anymore and tubes that contracted together to form thicker ones, until finally some of them resulted in round cell aggregates Although all mesenchymal cell tested were able to rearrange to form a network on their own, but the network did not last long as cells had formed huge cell aggregates at 12 hours... segregation of the cell types (Fig 1-12) As differences in the quantity of sprouts were rather subtle when compared within one ratio of EC to mesenchymal cells, most observations are of qualitative nature Pericytes contribute to the formation of cord structures in a monolayer co-culture To study the effect of pro -angiogenic drugs a co-culture assay of fibroblasts and EC is often engaged (Raghunath et al 2009) . PERIPHERAL BLOOD: A SIMPLE CELL SOURCE FOR THE GENERATION OF ANGIOGENIC PROGENITORS FROM MONOCYTES ANNA MARIA BLOCKI (B.SC. UNIVERSITY OF APPLIED SCIENCES OF GELSENKIRCHEN). sprouting assay! !34! 2D cord formation assay! !35! Statistical analysis! !35! Chapter 2 : Blood- derived angiogenic cells (BDAC) represent a pericytic population and enhance early stages of angiogenesis.!. the last year helped with the conduction of some of the experiments. Together we established the marker profile and she performed the majority tube formation assays on matrigel. The raw data