Nanoparticles used to stimulate growth of new neurons in adult brain

May 20 2009

University at Buffalo researchers have identified a new mechanism that plays a central role in adult brain stem cell development and prompts brain stem cells to differentiate into neurons.

Their discovery, known as Integrative FGFR1 Signaling (INFS), has fundamentally challenged the prevailing ideas of how signals are processed in cells during neuronal development.

The INFS mechanism is considered capable of repopulating degenerated brain areas, raising possibilities for new treatments for Parkinson's disease, Alzheimer's disease and other neurodegenerative disorders, and may be a promising anti-cancer therapy.

Michal Stachowiak, Ph.D., director of the Molecular and Structural Neurobiology and Gene Therapy Program at UB, lead the research team that discovered INFS.

Results of the research appear in a recent issue of Integrative Biology at http://xlink.rsc.org/?doi=B902617G.

The approach uses gene engineering and nanoparticles for gene delivery to activate the INFS mechanism directly and promote neuronal development. The INFS-targeting gene can prompt these stem cells to differentiate into neurons.

Stachowiak, UB associate professor of pathology and anatomical sciences in the UB School of Medicine and Biomedical Sciences, said the research team set out to see if it is possible to generate a wave of new neurons from stem cells and direct them to the affected areas using a mouse model.

"In this way, targeting the INFS potentially could be used to cure certain brain diseases, particularly in the case of a stroke or injuries that happen as a single episode and are not continuously attacking the brain," he said.

"This study provides proof of concept for a novel approach to the treatment of neuronal loss by means of therapeutic gene transfer. This is a particularly attractive alternative to viral-mediated gene transfer.

"The health risks associated with using viruses to carry genes in this type of gene transfer have led to the search for safer means of gene delivery," noted Stachowiak. "Nanotechnology offers an unprecedented advantage in enhancing the efficacy of non-viral gene delivery."

Stachowiak and his wife, Ewa K. Stachowiak, Ph.D., research assistant professor of pathology and anatomical sciences, along with their postdoctoral fellows and graduate students, have spent more than 15 years studying the mechanisms controlling natural neurogenesis, the creation of new neurons.

Brain injuries, stroke and progressive chronic diseases such as Parkinson's or Alzheimer's disease result in an extensive loss of neurons, accompanied by functional deterioration in the affected brain tissue. Such neurodegenerative diseases are a major health concern, given the rising aging population worldwide.

In addition, neurodevelopmental disorders, such as autism and schizophrenia, diminish the production of neurons and disrupt the brain's cellular structure.

"Manipulation of pre-existing adult stem cells to repopulate diseased areas of the brain holds the key towards the treatment of these neurodegenerative and, possibly, neurodevelopmental disorders," said Michal Stachowiak.

"However, after birth, the ability of the brain's stem cells to form the necessary new neurons normally is greatly diminished, and the mechanisms controlling natural neurogenesis are not well understood."

The neurogenic potential of targeting INFS was described initially in cultured stem cells in vitro by the Stachowiak team. Following these initial studies, together with a team of UB chemists that included Indrajit Roy, Ph.D., Dhruba Bharali, Ph.D., and Paras N. Prasad, Ph.D., Stachowiak's group investigated the use of organically modified silica nanoparticles as gene delivery vehicles into the stem cells of the brain in vivo.

Prasad is executive director of the UB Institute for Lasers, Photonics and Biophotonics and SUNY Distinguished Professor in the departments of Chemistry, Physics, Electrical Engineering and Medicine. Roy is an assistant research professor in the institute; Bharali was a research associate.

Injae Shin, Ph.D., an expert in genetics at Yonsei University, Seoul, Korea, in an online article on the Chemical Biology Web site, called the work "exciting." He noted that it has the potential to treat neurological diseases, but pointed out the need for further development of gene delivery methods for the treatment of neuronal loss.

Stachowiak and colleagues currently are working on such approaches.

"Targeting the INFS mechanisms by small molecules could potentially replace the need for gene transfers and create a classical drug therapy for the neuronal loss," said Ewa Stachowiak. "Now that we know the mechanism, we can search effectively for the means to control it."

Additional contributing authors working at the Molecular and Structural Neurobiology and Gene Therapy Program are Yu-Wei Lee, a UB graduate student in pathology and anatomical sciences; Mariolina Capacchietti, a visiting graduate student from Camerino, Italy; and John M. Aletta, from CH3 Biosystems LLC, an independent biotechnology startup company with facilities in UB's New York State Center of Excellence in Bioinformatics and Life Sciences. The research was supported by a grant from The John R. Oishei Foundation to Prasad and Michal Stachowiak, and by grants from the UB Interdisciplinary Research and Creative Activities Fund and New York Stem Cell Science (NYSTEM) to Stachowiak.

The University at Buffalo is a premier research-intensive public university, a flagship institution in the State University of New York system and its largest and most comprehensive campus. UB's more than 28,000 students pursue their academic interests through more than 300 undergraduate, graduate and professional degree programs. Founded in 1846, the University at Buffalo is a member of the Association of American Universities.