Research
A central goal of the Redenti Lab is to advance understanding of cell and tissue communication to contribute to repair of damaged neural tissue. To identify molecular mechanisms contributing to intrinsic cellular intelligence and decision-making we draw on evolutionary and developmental biology, bioinformatics, computer modeling and collaborative bioengineering strategies.
Systems Level Modeling of Migratory Signaling for Transplantable Cell Populations
One approach for studying cell decision-making involves evaluating active gene networks and receptor dynamics facilitating migration of transplantable stem and progenitor cells for repair of damaged nerve tissue. In this line of research we utilize bioinformatics to model and correlate transplantable cell gene expression to guidance signals present in the extracellular environment of damaged neural tissue. From bioinformatics libraries we then test stem cell migration in engineered microfluidic devices with biomimetic extracellular matrix and chemotactic gradients found in developing or damaged neural tissue. Bioengineered microenvironments allow for mathematical in silico modeling of migration that is verified using live-cell imaging of individual cell migratory dynamics. In later stages of analysis, cells with demonstrated ability to migrate in bioengineered environments are tested for migration in neural tissue. A goal is to generate a library of chemotactic models to advance stem-cell transplantation as a practical therapy. Collaborator: Maribel Vazquez Biomedical Engineering, City College of New York
Stepwise progression of migration analysis experimental paradigm: (A) Bioinformatics generated gene-network map focusing on the epidermal growth factor receptor signaling in our transplantable retinal progenitor cell population, (B) molecular analysis showing chemotactic receptor expression on the transplantable cell population, (C) Bioengineered microfluidic device for generating mathematical models of chemotactic gradients and analyzing individual cell motility.
Electrogenic Development and Response Dynamics of Progenitor Cells
A second active phase of research in the lab involves analysis of stem and progenitor cell dynamic interactions with bioengineered transplantable polymer substrates for neural tissue repair. Currently our focus is engineering composites of transplantable neural progenitor cells on electrically conductive biodegradable substrates with biomimetic properties. Drawing from developmental biology, we have created an in vitro simulation of the spontaneous electric wave patterns influencing gene expression, axon and synapse genesis in nerve tissue in vivo. We use gene expression, calcium imaging and morphologic analysis to characterize polymer guided enhanced neural phenotypes. Goals of this work include, characterizing basic mechanisms of neuronal development and plasticity, testing biocompatibility of new polymer substrates in vitro and contributing to engineering approaches for neural tissue repair. Collaborator: Gordan Vunjak-Novoakovic Biomedical Engineering, Columbia University
Conductive polymer delivered biomimetic electrical wave stimulation to analyze neuronal differentiation: (A) Engineered electrical bioreactor for cell seeding in eight wells onto the conductive polymer substrate polypyrrole (PPy), (B) microscopy of control and stimulated cells morphologies, (C) quantification of enhanced dendritic length of stimulated cell populations.
Characterization of Extracellular Vesicle Kinetics and Molecular Cargo
An additional line of research in the lab involves analysis of stem cell and progenitor cell extracellular vesicle release rate, morphology and molecular content. Our initial studies have focused on induced pluripotent stem cell microvesicle characterization. We use Nanosight analysis, electron microscopy, proteomics, gene expression analysis and in silico modeling. Goals of this work include defining the significance of stem cell extracellular vesicles in maintaining pluripotency and toward application in nerve tissue regeneration.
Induced Pluripotent Stem Cell Extracellular Vesicles: (A) Microvesicle nanometer diameter range and concentration derived from iPSCs at 12 h, 122 ± 2.3 nm, (B) PKH26 (red) labeling of emerging vesicles at the iPSC lipid bilayer (scale: 10 μm), (C) SEM of an MV population with measured diameters of 73.60 and 93.42 nm, (D) iPSC microvesicles contain mRNA involved in the maintenance of pluripotency including Oct-3/4, Nanog, Klf4.
Identification of natural products with anticancer and chemopreventive activities
Additional research in the lab, led by Linda Saxe Einbond, Ph.D., provides insights into the roles of genetic and dietary factors in human cancer causation, with the ultimate-goal of cancer prevention. The methods employed include cell culture, microarray, RT-PCR, Western blot, RNAi and immunohistochemical studies of human tumors. In recent studies, we elucidated mechanisms by which black cohosh and other naturally occurring compounds (digitoxin from foxglove, carnosic acid from rosemary, curcumin from turmeric, traditional preparations of kava) inhibit growth and induce apoptosis in human breast, colon and cervical cancer cells. Collaborators: Dr. Michael Balick, The New York Botanical Garden; Drs. Morando Soffritti and Fabiana Manservisi, The Ramazzini Institute.
Mechanism of action of curcumin: Transcriptomic analysis of liver tissue after treating rats with turmeric containing 74% curcumin indicates curcumin alters the immune response, angiogenesis and fatty acid synthesis; combination of curcumin with the statin simvastatin shows curcumin synergizes with simvastatin on colon cancer cells.
In addition to current projects described above, team members of the Redenti Lab are involved in collaborative work to investigate and in silico model molecular cell-cell signaling influencing neural tissue development and regeneration. In addition, in collaboration with pharmacology and biochemistry groups, we are analyzing novel compounds for application in neuroprotection and neuroblastoma treatment. We welcome email contact, collaborations and inquiries.
