6 results on '"Joddar B"'
Search Results
2. A surface-tethered model to assess size-specific effects of hyaluronan (HA) on endothelial cells
- Author
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IBRAHIM, S, primary, JODDAR, B, additional, CRAPS, M, additional, and RAMAMURTHI, A, additional
- Published
- 2007
- Full Text
- View/download PDF
Catalog
3. Spatial gradients of chemotropic factors from immobilized patterns to guide axonal growth and regeneration.
- Author
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Joddar B, Guy AT, Kamiguchi H, and Ito Y
- Subjects
- Animals, Axons drug effects, Cell Differentiation, Cells, Cultured, Chickens, Growth Cones drug effects, Growth Cones physiology, Immobilized Proteins pharmacology, Neurons drug effects, Axons physiology, Nerve Growth Factors pharmacology, Nerve Regeneration, Neurons physiology, Semaphorin-3A pharmacology, Tissue Engineering methods
- Abstract
In this study, we investigated the effect of varying localized concentration gradients of NGF and Sema3A on the axonal outgrowth of embryonic chick DRG explants and primary neurons in vitro. Immobilized 2D NGF or Sema3A micropatterns were produced using photolithography on tissue culture cover slips. Two distinct regions were identified: slow, with little or no change in concentration of chemotropic factor; and steep, with a transition from low to high. The direction of axonal outgrowth was defined as proximal or distal, with proximal growing towards the higher concentration of immobilized NGF/Sema3A and vice versa for distal. Axons grew preferentially in the proximal direction when explants were seeded onto steep NGF, and distally in response to steep Sema3A. On slow NGF, or on slow Sema3A there was no difference in the directional specificity of axonal outgrowth. DRG primary neurons seeded onto steep NGF migrated proximally, whereas neurons seeded onto slow NGF migrated in all directions. Conversely, neurons seeded onto steep or slow Sema3A did not extend any axons. Our 2D immobilized micropatterns of chemotropic factors show promise for further development of in vitro nerve tissue engineering studies., (Copyright © 2013 Elsevier Ltd. All rights reserved.) more...
- Published
- 2013
- Full Text
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4. The effects of covalently immobilized hyaluronic acid substrates on the adhesion, expansion, and differentiation of embryonic stem cells for in vitro tissue engineering.
- Author
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Joddar B, Kitajima T, and Ito Y
- Subjects
- Alkaline Phosphatase metabolism, Animals, Base Sequence, Blotting, Western, Cells, Cultured, DNA Primers, Embryonic Stem Cells enzymology, Extracellular Matrix Proteins metabolism, Hyaluronan Receptors metabolism, Hyaluronic Acid chemistry, Mice, Molecular Weight, Phosphorylation, Polymerase Chain Reaction, STAT3 Transcription Factor metabolism, Cell Adhesion drug effects, Cell Differentiation drug effects, Cell Proliferation drug effects, Embryonic Stem Cells cytology, Hyaluronic Acid pharmacology, Tissue Engineering
- Abstract
We investigated the in vitro effects of the molecular weight (MW) of hyaluronic acid (HA) on the maintenance of the pluripotency and proliferation of murine embryonic stem (ES) cells. High (1000 kDa) or low (4-8 kDa) MW HA was derivatized using an ultraviolet-reactive compound, 4-azidoaniline, and the derivative was immobilized onto cell culture cover slips. Murine ES cells were cultured on these HA surfaces for 5 days. High-MW HA interacted with murine ES cells via CD44, whereas low-MW HA interacted with these cells mostly via CD168. ES cells grown on both high- and low-MW HA appeared undifferentiated after 3 days. However, more cells adhered, proliferated, and exhibited greater amounts of phospho-p42/44 mitogen-activated-protein-kinase on low- compared with high-MW HA. Expression of Oct-3/4 and phosphorylation of STAT3 were enhanced by ES cells on low-MW HA, not on high-MW HA. After release from HA, cells cultured on low-MW HA in the presence of differentiating medium showed enhanced expression of α-SMA or CD31 compared with cells cultured on high-MW HA. It was concluded that low-MW HA substrates were effective in maintaining murine ES cells in a viable and undifferentiated state, which favors their use in the propagation of ES cells for tissue engineering., (Copyright © 2011 Elsevier Ltd. All rights reserved.) more...
- Published
- 2011
- Full Text
- View/download PDF
5. Elastogenic effects of exogenous hyaluronan oligosaccharides on vascular smooth muscle cells.
- Author
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Joddar B and Ramamurthi A
- Subjects
- Animals, Aorta cytology, Cell Proliferation, Cells, Cultured, Collagen metabolism, Collagen ultrastructure, Elastin ultrastructure, Extracellular Matrix chemistry, Extracellular Matrix metabolism, Fibrillins, Guided Tissue Regeneration methods, Hyaluronic Acid chemistry, Hyaluronic Acid metabolism, Microfilament Proteins metabolism, Myocytes, Smooth Muscle cytology, Oligosaccharides chemistry, Oligosaccharides metabolism, Rats, Elastin metabolism, Hyaluronic Acid pharmacology, Muscle, Smooth, Vascular cytology, Myocytes, Smooth Muscle drug effects, Myocytes, Smooth Muscle metabolism, Oligosaccharides pharmacology
- Abstract
Prior studies suggest that hyaluronan (HA), a glycosaminoglycan, may upregulate innately poor elastin matrix synthesis by adult vascular smooth muscle cells (SMCs). HA scaffolds could thus be useful to regenerate damaged vascular elastin. In an earlier study, we established that the elastogenic effects of non-oligomeric HA are fragment size- and/or dose-specific. We currently investigate the pro-elastogenic effects of exogenous HA oligomers on rat aortic smooth muscle cells (RASMCs). RASMCs were cultured with pure HA oligomers (4-mers) and mixtures (4-8mers) obtained by enzymatic digestion of long-chain HA (MW approximately 2000kDa). Polyacrylamide gel electrophoresis (PAGE)/Matrix Assisted Laser Desorption/Ionization Spectroscopy Time-Of-Flight Analysis (MALDI-TOF) showed HA digestates to contain a mixture of 4-8mers with a predominance of 4-mers (75+/-0.4% w/w). Cell layers supplemented with both pure HA 4-mers or oligomer mixtures showed proliferation levels similar to non-HA controls over 21 days of culture. Pure 4-mers and oligomer mixtures enhanced DNA-normalized output of tropoelastin by 1.6 and 1.8 times, respectively, and that of matrix elastin by approximately 2.7 times relative to controls. Sodium dodecyl sulfate (SDS)-PAGE/Western Blot and a desmosine assay semi-quantitatively confirmed the observed biochemical trends for tropoelastin and matrix elastin, respectively. HA oligomers induced enhanced synthesis of the elastin crosslinker, desmosine, and appeared to stabilize the elastin matrix by suppression of elastin-laminin receptor (ELR) activity relative to controls. Transmission electron micrographs (TEMs) showed elastin deposits within oligomer-supplemented cultures to be distinct, longitudinally oriented, aggregating fibrils, and clumps, and to be less abundant and mostly amorphous in controls. HA oligomers preserved normal fibrillin-mediated elastin matrix deposition. Results suggest that HA oligos are highly pro-elastogenic, promote elastin fibril formation, and stabilize elastin matrix and may thus be usefully incorporated into scaffolds for guided elastin regeneration. more...
- Published
- 2006
- Full Text
- View/download PDF
6. Fragment size- and dose-specific effects of hyaluronan on matrix synthesis by vascular smooth muscle cells.
- Author
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Joddar B and Ramamurthi A
- Subjects
- Animals, Biocompatible Materials administration & dosage, Biocompatible Materials chemistry, Cell Culture Techniques methods, Cell Proliferation, Cells, Cultured, Dose-Response Relationship, Drug, Extracellular Matrix drug effects, Materials Testing, Muscle, Smooth, Vascular drug effects, Particle Size, Rats, Surface Properties, Extracellular Matrix physiology, Hyaluronic Acid administration & dosage, Hyaluronic Acid chemistry, Muscle, Smooth, Vascular cytology, Muscle, Smooth, Vascular physiology, Tissue Engineering methods
- Abstract
Tissue engineering of vascular elastin matrices disrupted by mechanical injury, disease, or congenitally absent, is among other factors, limited by the lack of suitable cell scaffolds to up-regulate and guide innately poor elastin synthesis by adult vascular smooth muscle cells (SMCs). Evidence suggests that scaffolds based on hyaluronan (HA), a glycosaminoglycan, may be useful to elicit elastogenic cell responses, although these effects appear to be dictated by HA fragment size and/or dose. This study investigates the efficacy of a simple, frequently adopted exogenous HA supplementation model to test this hypothesis. Rat aortic SMCs were cultured with HA (2 x 10(6) Da (HMW) > or = MW < or = 2.2 x 10(4) Da) supplemented at doses between 0.2 and 200 microg/ml. Cell layers were biochemically assayed for DNA, elastin and collagen content. Fragmented, but not high molecular weight (HMW) HA, stimulated cell proliferation in inverse correlation fragment size while the opposite effect was observed for synthesis of soluble and matrix elastin; almost no dose effects were observed within any group. SDS-Page/Western Blot and a desmosine assay semi-quantitatively confirmed the observed biochemical trends for tropoelastin and matrix elastin, respectively. Quantitative differences in elastin deposition were mirrored in TEM micrographs. Elastin was mostly deposited in the form of amorphous clumps but fibers were increasingly present in cell layers cultured with HMW HA. HA and its fragments did not disrupt normal fibrillin-mediated mechanisms of elastin matrix deposition. While the current outcomes confirm that the effects of HA on elastin synthesis are fragment size-specific, this study shows that an exogenous supplementation model does not necessarily simulate cellular matrix synthesis responses to HA-based biomaterial scaffolds. more...
- Published
- 2006
- Full Text
- View/download PDF
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