Dimitris G. Placantonakis, MD, PhD

Dimitris G PlacantonakisAssistant Professor of Neurosurgery
Director, Neurosurgical Laboratory for Stem Cell Research
MD/PhD, 2003 NYU School of Medicine

Skirball 5th floor, Lab 16
NYU School of Medicine
540 First Avenue
New York, NY 10016
Tel: (212) 263-6414
E-mail: dimitris.placantonakis@nyumc.org
Lab website: http://placantonakislab.med.nyu.edu/

Research Theme(s): Stem Cell Biology, Human Embryonic Stem Cells, Human Induced Pluripotent Stem Cells, Glioblastoma Stem Cells, Motor Neuron, Neurogenesis, microRNA, Glioblastoma/glioma, Schizophrenia, Epilepsy

Keywords: Stem Cells, Motor Neurons, microRNAs, Glioblastoma, Schizophrenia, Epilepsy

Research Summary:

My laboratory studies the regulation of stem cell function during neurogenesis, as well as in malignant brain tumors and neuropsychiatric diseases. By definition, stem cells possess two fundamental properties: self-renewal, the ability to preserve stemness; and pluri- or multi-potency, the ability to differentiate to different types of progeny. Our group investigates the molecular mechanisms that govern self-renewal and differentiation potential of human stem cells both in normal neural development and in disease processes, such as brain cancer and neurological disorders.
A major project in our laboratory revolves around understanding the role that microRNAs play in motor neurogenesis using human embryonic stem cells as our model. In vitro specification of human spinal motor neurons is hampered by limited yields, partly due to the fact that neural stem cells remain locked in their “stem” state. Our hypothesis is that microRNAs may be able to facilitate differentiation and suppress stemness in neural stem cells by targeting specific pro-stemness transcripts.  Indeed, our previous work identified a microRNA pool that becomes upregulated during motor neurogenesis. We use molecular genetics to test the function of different microRNA candidates in this developmental process in vitro.  Moreover, we use computational approaches to identify putative targets of microRNAs in silico, which we then test in our system in vitro. Our goal is to understand the molecular machinery underlying human motor neurogenesis and to use our knowledge to design better treatments for motor neuron disorders.

A second project in our laboratory is aimed at understanding the decision-making of stem-like cells in glioblastoma. Glioblastoma is an aggressive form of brain cancer, in which stem-like cells termed glioblastoma stem cells (GSCs) can recapitulate the entire tumor, while remaining resistant to chemotherapy and radiation. We are developing a novel model system that will allow us to  track GSCs and their progeny in vivo in the mouse brain using 2-photon microscopy (in collaboration with Dr. Wenbiao Gan at Skirball).  Moreover, we are testing novel viral vectors for their ability to specifically transduce GSCs in vitro and in vivo (in collaboration with Dr. Christian Buchholz in Germany). Our ultimate goal is to translate our findings to the clinic and develop novel therapeutic approaches for glioblastoma.

Finally, we are collaborating with clinical investigators at NYU Medical Center to develop induced pluripotent stem cell lines from patients with neuropsychiatric diseases, including schizophrenia and epilepsy. We hope that this effort will improve our understanding of neural stem cell and neuronal function in such disorders. 

Selected publications: