A major challenge in physiology is bridging the gap between molecular and integrative functions, or how processes occurring at the cell level are organized to convey systems functions. The genetic model organism C. elegans exhibits a rhythmic behavior that occurs every 45 seconds, and a variety of cell signaling processes contribute to the behavioral output. The project is designed to exploit the power of the nematode model system to explore functional interactions between these processes. The project will also study a novel mechanism for fast cell-cell communication, which forms the basis for one component of the rhythmic behavior. The investigators will employ during the course of these studies fluorescent biosensors to measure cell signaling in live worms, as well as pharmacology, genetics, and molecular techniques to address how cell signaling at the molecular level is translated into behavior in live organisms. This work could potentially transform our view of cell signaling, leading to the emergence of a new area of study with important implications for how cells communicate with one another to convey behavior. The project will provide training for two Ph.D. students and summer research opportunities for several undergraduate students, with a strong emphasis on minority applicants. As a part of this project, the investigators will also create and maintain a website that can be accessed and understood by the layperson.
Final outcomes from this project will be highlighted in two categories: broader impact and intellectual merit, as defined by NSF guidelines. Broader Impact (bulleted, with details following): Broadened participation in biomedical research of: trainees from underrepresented groups, including ethnic minorities and those with physical disabilities. trainees from predominantly undergraduate institutions. local undergraduates and high-school students engaged in honors courses. Allowed a graduate student from Brazil to complete a three-month fellowship in the lab. Resulted in a local graduate student obtaining his PhD. Trainees have gone on to both postdoctoral fellowships and tenure-track positions. The entire laboratory participated in youth outreach programs, including a summer program for high-school students run by the Life Sciences Learning Center at the University of Rochester. Our trainees from the University of Rochester included those from underrepresented ethnic backgrounds such as Native American, Latin American (x2), and African American, as well as a physically-disabled individual (paraplegic). Three undergraduate students were with us for over two years apiece and one of these students graduated with distinction in research based upon her senior honors thesis. Her work has since been published. Another is in her third year of medical school at the University of Rochester. A high-school student who worked with us for two years entered the University of Rochester as an undergraduate, continued work for several years, and has since been accepted into medical school. One of our own graduate students was awarded a PhD for his work on this project and authored six peer-reviewed manuscripts during his time in the lab. He is now a postdoctoral fellow, and another trainee obtained a tenure-track faculty position. This award also supported collaborations with labs from predominantly undergraduate universities, including Oberlin College (in conjunction with an REUI award made there) and Marquette University, as well as labs overseas, such as University College London, England and Universidade de São Paulo, Brazil. In the case of Oberlin, one of the undergraduates was granted the David S. Bruce Excellence in Undergraduate Research award by the American Physiological Society and was first author on the resulting paper. Moreover, a Brazilian student from Universidade de São Paulo visited the lab for three months in 2011, returned to Brazil with the C. elegans model system in hand and recently re-visited our lab to prepare a video-protocol for the Journal of Visual Experiments. It is important to note that all of these collaborations resulted in publications. Finally, we have designed a website that highlights the work we do in the lab (www.NehrkeLab.com). The site is always subject to enrichment, and we will continue to enhance its functionality to facilitate communication with both the public and the scientific community. Intellectual Merit (bulleted, with details following): Ten publications resulted from the past period’s funding. A WormBook chapter on Epithelial Membrane Transport is in press. Two manuscripts are in preparation C. elegans express a simple behavior whose timing is controlled by oscillatory Ca2+ signaling. The posterior cells of the intestine are the behavioral pacemaker, and the canonical signaling cascades that regulate basal, rhythmic Ca2+ oscillations in these cells have been well-characterized. However, ion transport during defecation is essential for nutrient uptake and helps to set metabolic tone. Our work has led to a more detailed understanding of the molecular processes that regulate integrative physiologic events during this rhythmic behavior and help to maintain cellular and organismal homeostasis. Specifically, findings that will have likely impact on the field include the discovery that protons can act like a fast neurotransmitter, communicating information directly between the intestine and adjacent muscle cells, and that proton secretion from the intestine occurs through a conserved family of epithelial transport proteins whose activities have never before been linked to trans-cellular communication. We have also characterized the relevant signaling pathways and mechanism through which this is regulated. Work in collaboration with students from Oberlin College led to the identification of an accessory protein that contributes to the process, and research is underway to elucidate its precise mechanism of action. Our work with the group at Marquette University led to the discovery of a novel mechanism by which the microRNA miR-786 contributes to the behavioral pacemaker. It is possible that orthologous microRNAs in mammals may act through a conserved process, which would shed light on their mechanism of action. We have also collaborated with colleagues at University College London to describe metabolic signaling cascades that are central to cell and organismal death. This latter work was highlighted by many news sources, including ScienceDaily, the Smithsonian magazine, and Scientific American.
