2006 — 2010 |
Barresi, Michael |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Rui: the Role of Slits and Robos During Axon and Glial Cell Guidance in the Forebrain
Communication between the left and right hemispheres of the brain requires precisely positioned commissures made up of neuronal processes called axons that cross the midline. The guidance of axons across the midline occurs during embryonic development, and this guidance is controlled by an elaborate communication system between the pathfinding axons and their growth environment. The growth environment provides both the necessary growth substrate as well as strategically positioned attractive and repellent cues that all together direct specific pathfinding axons across the midline in the correct position. The main goal of this research is to understand how the diversity of Slit-Robo signaling controls the positioning of commissures as well as their glial growth substrate in the vertebrate forebrain. To accomplish this goal the Barresi lab has characterized a simple system in the zebrafish forebrain to simultaneously assay commissural axons, their astroglial growth substrate, and the Slit-Robo guidance system. The experiments outlined in this proposal will fully exploit the embryological, molecular and genetic techniques available in zebrafish to breakdown the synergistic roles of the Slit-Robo guidance system during astroglial bridge assembly and commissure formation in the diencephalon. Recently Dr. Barresi and colleagues have shown that commissural axons grow along a bridge-like structure made of astroglial cells. In addition, both repellent and potentially positive Slit cues function not only to guide axons across the forebrain, but also to set up the correct positioning of the midline astroglial bridge. One aim of this proposal is to test whether a particular Slit family member, slit1a, is sufficient to attract commissural axons and astroglial cells to the midline. Assaying this novel function will be accomplished by temporally and spatially misexpressing slit1a in the diencephalon of wild type embryos as well as in you-too (Gli2) mutant embryos that have a reduction in slit1a expression. Interestingly, roundabouts (robo), the Slit receptors, are differentially expressed in both commissural neurons and the astroglial bridge. The remaining proposed experiments are designed to decipher which of the four Robos (robo1, 2, 3 or 4) individually or synergistically function to mediate Slit repulsion or attraction for either commissural axons or astroglial cells within the diencephalon. This will be accomplished through the use of anti-sense Morpholino oligonucleotide gene knock-down techniques designed specifically against the four different robos, and by utilizing two mutant fish lines that have a loss of astray (robo2) or twitch-twice (robo3) gene function. Completion of these aims will help us to better understand the molecular (Slit-Robos) and cellular (astroglial) cues that influence midline axon crossing.
At Smith College, the Barresi lab is committed to involving undergraduate students in this research, in particular woman and woman from underrepresented groups will be the main contributors carrying out these studies.
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1 |
2008 — 2011 |
Briggs, Richard Barresi, Michael |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Mri: New Instrumentation For High Resolution 4d Imaging
A grant has been awarded to Smith College under the supervision of Dr. Michael J. Barresi and Co-PI, Dr. Richard Briggs to acquire high-resolution microscopy for research in live cell imaging. The Center for Microscopy and Imaging at Smith will house the NSF supported acquisition of Leica?s SP5 Laser Scanning Confocal Microscope with live cell imaging capabilities. Researchers at Smith College, as well as the other institutions participating in the Five College Consortium (Amherst, Mount Holyoke, and Hampshire College, and the University of Massachusetts), will enter a new frontier of biological research, studying molecules, cells and tissues in the living state. The remarkable flexibility of this confocal microscope will support a diverse array of research topics that represent three unifying themes of investigation based on scale: the study of specific molecular mechanisms; understanding unicellular structure, function and behavior; and analysis of whole organism development and physiology. The proposed instrumentation will directly impact the research programs of 18 faculty from the Five Colleges listed above as well as an estimated 30 graduate students and 80 undergraduates.
Smith College is the nation?s largest liberal arts college for women and is among the top schools producing the greatest number of woman pursuing careers in science. Therefore, one of the main purposes of this newly funded instrumentation will be training highly motivated, diverse undergraduates, many from underrepresented groups, including first-generation college students. This modern microscope system will also serve as a focal point for various outreach activities to area schools and summer science programs targeting young women from underrepresented minority groups. Lastly, because of the strong Five College support for this instrument, this confocal microscope will be an important catalyst for inter-college collaborations that would not typically develop. Such interactions can help stimulate new directions and open doors for students to pursue careers in science and research. Because this instrumentation will provide whole new levels of analysis previously unavailable, the most exciting impacts will probably be those scientific findings that cannot even be predicted.
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1 |
2009 |
Barresi, Michael Joseph |
R15Activity Code Description: Supports small-scale research projects at educational institutions that provide baccalaureate or advanced degrees for a significant number of the Nation’s research scientists but that have not been major recipients of NIH support. The goals of the program are to (1) support meritorious research, (2) expose students to research, and (3) strengthen the research environment of the institution. Awards provide limited Direct Costs, plus applicable F&A costs, for periods not to exceed 36 months. This activity code uses multi-year funding authority; however, OER approval is NOT needed prior to an IC using this activity code. |
The Role of Eg5 in Radial Glial Development in the Zebrafish Spinal Cord
DESCRIPTION (provided by applicant): In the developing vertebrate central nervous system, radial glial cells play critical roles in supporting brain architecture and, more recently discovered, possess self-renewing capabilities as well as gliogenic and neurogenic potential. Radial glial cells have been known since the time of Cajal, but over the last few decades the increase of available markers particularly glial fibrillary acidic protein has made their identification as astroglial cells increasingly easier. Much of our understanding of radial glial cells originates from their function as a scaffold for the migration of newly born neurons in the developing mammalian cerebral cortex. However, current knowledge of the stem cell-like potential of radial glial cells is very limited, and in particular what the surrounding radial glial niche of the embryonic ventricular zone looks like. What glial or neuronal cell types are derived from radial glia in the embryonic spinal cord? Do radial glia have a unique intrinsic regulator of cell division to carry out the mechanics of continued self-renewal? The investigator proposes to fully exploit the embryological, molecular, and genetic techniques that are in some cases uniquely amenable to zebrafish to address these questions. He proposes to (1) establish a three-dimensional map of astroglia and radial glia within the embryonic spinal cord, and (2) determine whether the eg5 kinesin motor protein is required cell autonomously for radial glial cell division. By combining both a gfap transgenic line driving the expression of GFP with elegant gastrula staged transplantations, The investigator will target clusters of scattered gfap:GFP+ cells into a non-transgenic spinal cord. Imaging of these astroglial cells with high resolution confocal microscopy will provide a full cellular morphological analysis, shedding light on the types of astroglia present in the embryonic spinal cord and how they interact with other cell types. Furthermore, the investigator identified an eg5 zebrafish mutant that exhibits cell proliferative defects in radial glial cells. By utilizing this mutant as well as testing several anti-cancer drugs targeting Eg5, he will determine how this gene regulates radial glial cell division and whether other cell types derived from radial glia are also affected by the loss of Eg5. In this revitalized field of glial biology and a model system lacking foundational data on astroglial development, these results will provide fundamental information of radial glial development that can be the springboard for many new avenues of research. Understanding the role of Eg5 in the developing embryo will also provide critical information regarding the use of anti-cancer drugs targeting Eg5 in humans especially for glial derived tumors, such as congenital gliomas.
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0.958 |
2011 — 2017 |
Barresi, Michael |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Career: the Role of Axon-Glial Cell Interactions During Commissure Formation in the Zebrafish Forebrain.
Communication between the left and right hemispheres of the brain requires precisely positioned neuronal cells with extensions called axons that span the midline of the organism. During embryogenesis these midline-crossing neurons are formed through an elaborate process of cell guidance that instructs pathfinding axons across the midline prior to reaching their synaptic targets. This process of "axon guidance" requires important cell-to-cell interactions between the pathfinding axon and the cells in its local environment. The Barresi Lab seeks to determine what the cell types are that make up the growth substrate for pathfinding axons, define the live interactions that occur, and determine whether a protein called Slit1a mediates these interactions at the midline.
The Barresi lab has characterized a simple system to assay midline-crossing axons interacting with a glial cells functioning as a growth substrate in the developing forebrains of living zebrafish zebrafish embryos. Using this system, they will also test the role Slit-Roundabout molecular signaling plays in regulating this interaction. They propose to exploit the embryological, molecular and genetic techniques available with the zebrafish model system to test directly whether glial cells play a role in midline crossing of these axons. Additionally, they will test whether Slit1a positively mediates axon-glial interactions. Barresi hypothesizes that distinct populations of astroglia are required for midline crossing through a Slit1a-Robo1 mediated mechanism of axon-glial interaction. This work will provide a molecular, cellular and behavioral understanding of how neuron-glial interactions occur in the live developing brain, which could change our current understanding of brain development that is mostly based on fixed tissue analysis.
Importantly, Barresi has also created a collaborative outreach program between an underserved public high school, a biotech company, and Smith College to train high school teachers and students in molecular and developmental biology. This effort is aimed to excite and prepare underrepresented students to consider and succeed in the pursuit of higher education in STEM related fields.
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1 |
2015 |
Barresi, Michael Joseph |
R15Activity Code Description: Supports small-scale research projects at educational institutions that provide baccalaureate or advanced degrees for a significant number of the Nation’s research scientists but that have not been major recipients of NIH support. The goals of the program are to (1) support meritorious research, (2) expose students to research, and (3) strengthen the research environment of the institution. Awards provide limited Direct Costs, plus applicable F&A costs, for periods not to exceed 36 months. This activity code uses multi-year funding authority; however, OER approval is NOT needed prior to an IC using this activity code. |
Wnt Pathway Crosstalk Regulates Neural Stem Cell Proliferation During Spinal Cord Development in Zebrafish.
? DESCRIPTION (provided by applicant): Congenital brain disorders and many central nervous system cancers are in part caused by the misregulation of neural stem cells during embryonic and fetal development. In all vertebrates radial glial cells serve as the neural stem cell during these early periods of development. The brain is built through the proper regulation of radial glia division rates and differentiation of their progeny and alterations to radial glial development is suggested to be one of the primary modules of brain evolution. Understanding what the mechanisms are that regulate radial glial development will have broad implications to nervous system construction, disease states, tumorogenesis, and potentially the ability to unlock regenerative capabilities to treat CNS trauma and degenerative diseases. The fundamental process underling the ability of radial glial cells to build the nervous system and respond to disease or trauma is cell division, yet much still remains to be learned about the molecular mechanism that regulate radial glial division and differentiation. We study the developing zebrafish spinal cord as a simple model of neurogenesis, in which the role of radial glial cells and their progeny can be investigated at the tissue, cellular, and genetic levels. Previously during an insertional mutagenesis screen we identified a class of genes required for proper radial glial development in the spinal cord. With my first NIH R15 award, we investigated the role of kif11 as an intrinsic regulator of radial glial division during neural tube development. We showed Kif11 was necessary for radial glial progression through mitosis, which revealed reductions in specific neuronal and glial lineages dependent upon radial glia for their derivation. For this proposed competitive renewal we will focus on wnt5b, which causes increases to the number of mitotic radial glia like kif11 mutants but functions as a potential external regulator of radial glial cell proliferation. I present preliminary data that lends support for the central hypothesis that Wnt5b functions as a negative regulator of canonical Wnt/?-Catenin signaling, which results in alterations to the proliferation rate of radial glial cells that further impacts neurogenesis during development of the spinal cord. We will use a variety of combinatorial loss and gain of function approaches of both Wnt5b and Wnt/?-Catenin signaling to (1) characterize how the cell cycle in radial glia is influenced by wnt5b, (2) test which cells in the neural stem cll niche require wnt5b function, and (3) determine whether Wnt5b functions through Wnt/?-Catenin signaling to regulate radial glial division and differentiation. This investigation is particularly innovative for several reasons. We will take full advantage of the power of zebrafish genetics to manipulate the function of multiple genes with temporal control, visualize specific stem and post-mitotic cell populations in the live developing embryo, and detect changes in pathway response at the cellular level. We have uniquely adapted the use of Geographic Information Systems to apply spatial statistics to visual data sets for the highest level of objective quantification. Lastly, analysis of Wnt5b regulation of radial glial cell division will b guided by our mathematical modeling to shed light on the parameters of cell cycle control most related to changes in Wnt5b function. The comprehensive nature of this work ensures its broad impact upon the field of developmental biology. From the study of live radial glial cell behaviors during development to the molecular dissection of Wnt signaling pathways in the regulation of radial glial cell cycle control, there promises to be far reaching advances to our understanding of neural stem cells in both development and disease. One of the most important impacts will be to the education of students across the hierarchy of academia, which includes the direct participation of graduate students, the foundational contributions of the undergraduate research scientists in my lab, and the hundreds of primary and secondary education students that directly benefit yearly from my Student Scientists outreach program. Ultimately it is the fully committed integration of research and education, which will yield productive contributions to our knowledge of stem cell development in ways that impact a wide range of human health related needs while inspiring and training the next generation of problem solving scientists and medical professionals.
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0.958 |
2017 — 2021 |
Barresi, Michael |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Ios- Abr: Rui: Investigating Astroglial Development in the Zebrafish Forebrain.
Historically, the field of neuroscience has been neuron-centric, which has left a large gap in our understanding of the development and function of the other cells in the nervous system, called glia. Glial cells were traditionally thought to passively support neurons. The present research tries to answer foundational questions about how glial cells are involved in brain development, such as what the differences are among the types of glial cells that exist in developing brains, how glial cells support the actively-dividing cell populations that build the brain (neural stem cells), the role that glial cells play in the development of the blood-brain-barrier, and how glial cells affect the intricate pattern of connections that form in the developing brain. Zebrafish are used for this research because of the ease with which these questions can be studied in a vertebrate animal that is optically clear. This work combines the advantages of zebrafish genetics and embryology together with high resolution 5D microscopy (3 spatial dimensions followed over time for several different cell-marking colors) to precisely measure glial cell development, and to assess the role that an important molecule involved in cell-cell communication called Roundabout4 plays in these processes. In addition to greatly furthering scientific understanding of glial cell biology and development, this award will support the recruitment of a diverse set of student scientists through the establishment of a peer mentor training program, and the continuation of a primary and secondary education outreach program using zebrafish called Student Scientists.
This project explores the hypotheses that heterogeneous astroglia exist in the zebrafish embryonic forebrain to guide cell types at the midline that build neurons, commissures, blood vessels, and cartilage, and that Slit-Robo4 signaling underlies this astroglial mechanism of cell guidance. These hypotheses will be tested in three specific ways. First, the developmental ontogeny of forebrain astroglia will be characterized in detail. New transgenic reporters will be used to track every astroglial cell in the diencephalon with time lapse Lightsheet microcopy, and live cell behaviors will be used to chart the developmental derivation of forebrain astroglia during neurogenesis, commissure and blood vessel formation. Next, experiments will be carried out to see if Robo4 is required cell-autonomously for astroglial guidance during neural stem cell niche, postoptic commissure, and blood-brain barrier formation. A newly-created robo4 knockout will be used to determine exactly which cell populations require Robo4 function for progenitor cell generation in the stem cell niche, for the midline crossing of axons, and for astroglial-endothelial cell interactions during blood-brain-barrier development. Finally, Robo4 functions downstream of Slit signaling will be examined during commissure formation. Because Roundabout receptors mediate Slit signaling, functional interactions between Robo4 and Slit1a/2 will be investigated to see if they are responsible for Robo4-dependent astroglial behaviors.
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1 |
2019 |
Barresi, Michael Joseph |
R15Activity Code Description: Supports small-scale research projects at educational institutions that provide baccalaureate or advanced degrees for a significant number of the Nation’s research scientists but that have not been major recipients of NIH support. The goals of the program are to (1) support meritorious research, (2) expose students to research, and (3) strengthen the research environment of the institution. Awards provide limited Direct Costs, plus applicable F&A costs, for periods not to exceed 36 months. This activity code uses multi-year funding authority; however, OER approval is NOT needed prior to an IC using this activity code. |
The Bioelectrics of Axis Determination During Zebrafish Embryonic Development
PROJECT SUMMARY Bioelectric mechanisms are emerging to be novel regulators of organ specification, growth and patterning during normal as well as regenerative development of organisms. Bioelectric properties of cells are determined by membrane localized channels that regulate entry of charged ions. Our interest in this topic stems from original findings that indicate membrane potentials of cells in gastrula stage zebrafish embryos appear to be in different states over distinct regions of the embryo. We are interested in understanding how these distinct bioelectric states may be generated and what is their significance. Gastrulation is a complex developmental stage when the dorsal-ventral and animal-vegetal axes are specified and cells begin to acquire specific fates. During this stage diverse morphogens and their effectors interact with each other to restrict their zones of influence and induce cell differentiation. We have determined that phenotypes induced by chemical inhibition of FGF by SU 5402 could be rescued by global increase in membrane depolarization across the embryo. We hypothesize that modulation of membrane potential could be altering the threshold for the specific inhibited FGF effector. To dissect this our project aims to define whether there is any specific membrane channel that is regulating a FGF effector or conversely and whether there is a membrane channel being regulated by FGF. To achieve our desired aims in a systematic manner, we first propose to characterize the pattern of voltage membrane potentials across the zebrafish gastrula over time with voltage sensitive dyes and the use of genetically encoded voltage indicators. We then plan to define the specific ion transporters mediating these bioelectric patterns as well as determine if they can influence the expression of core morphogenetic pathways during axis determination. Lastly, we will interrogate the interactions that bioelectric signaling has with Fgf signaling during axis determination and elongation. Most importantly, this study will be primarily accomplished with the support of undergraduate researchers who are all women and 50% of who first generation or researchers of color.
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0.958 |