Professor
Neuroscience and Pharmacology
3213 WBSB

Phone: (615) 327-6358

dhood@mmc.edu

The research program of Darryl B. Hood is in the area of Environmental Health and Toxicology with a particular interest in the effects of exposure to environmental toxicants during critical periods of CNS development and the subsequent effects on behavioral learning in the offspring. The specific compounds of interest are polycyclic aromatic hydrocarbons (PAHs). The environmental contaminants of immediate concern to minority communities are released as emission by-products from industrial environmental polluters. Dr. Hood’s laboratory has been investigating and characterizing the health effects of polycyclic aromatic hydrocarbon exposure using various exposure regimens for over a decade. The long-term goal is to determine the mechanistic connection between environmental insults to experience-dependent neural activity and alterations in gene expression during the postnatal period when synapses are forming for the first time (PND7-14). The recent finding by a group at Vanderbilt [Morrow et al., (2008)] has illuminated the fact that deletions of certain genes that are regulated by neuronal activity or that certain regions of these genes are potentially involved in regulation of gene expression in environmental exposure-induced disease. This work has served to spotlight Dr. Hood’s studies where he is testing hypotheses of prenatal toxicant-induced insult to activity-dependent gene expression being causative for behavioral deficits in the neuropathology of at least a subset of environmental exposure-induced behavioral learning disorders.

Dr. Darryl B. Hood is a nationally recognized expert in the area of Neurotoxicology, with an intense focus on the effects of exposure to environmental pollutants on the developing brain and the resulting consequences on early-life cognitive processes. The specific environmental pollutants of interest in his studies are polycyclic aromatic hydrocarbons. These environmental pollutants are primarily released as emissions from combustion processes and from industrial polluters throughout the United States and disproportionately affect minority populations in urban areas. Dr. Hood’s laboratory has been investigating, characterizing and publishing the health effects resulting from in utero exposure to polycyclic aromatic hydrocarbons for well over a decade. 

New aspects of Dr. Hood’s research as a result of the recent receipt of the prestigious Simons Foundation Autism Research Initiative Award include understanding how in utero exposures during critical windows of brain development produce negative effects on neural function and behavior in offspring. Reconstituting neural currents that are suppressed during critical periods of development as a result of in utero exposure may be possible as a targeted therapy at birth-as a means to preserve the development of normal circuitry and thus normal behavior. These new aspects of Dr. Hood’s research offers the promise of advancing our ability to establish gene x environment connections between exposure-induced neurodegenerative states due to environmental insult during critical periods of brain development.

Dr. Hood has been continuously funded over the past decade by the National Institutes of Health. A grant entitled "Environmental Ah Receptor Agonists and Cognition" funded Dr. Hood’s studies at the level of 1.9 million dollars from 2000 to 2006 and was a part of a larger 5.4 million dollar Meharry Medical College initiative from the National Institute of Neurological Diseases and Stroke. 

Currently, Dr. Hood is the Principal Investigator of a $4-million dollar National Institutes of Environmental Health Sciences funded Meharry Medical College-Vanderbilt University School of Medicine Advanced Research Cooperation in Environmental Health Consortium. The title of this program project activity is “Mechanisms of Polycyclic Aromatic Hydrocarbon Toxicity”.

The overarching goal of ongoing research conducted in Dr. Hood’s laboratory at Meharry Medical College is to contribute to understanding of the etiology of a number of environmental-exposure influenced neurological disorders such as 1) autism spectrum disorder and 2) cognitive deficits observed in infants and children in communities located near landfills, industrial polluters, or other toxic waste sites.  Thus far, studies from Dr. Hood’s laboratory have provided mechanistic data that support associations between in utero environmental exposures, dysregulation of central nervous system development and behavioral deficits. From a cumulative risk-assessment perspective, data from Dr. Hood’s laboratory has contributed to the database that addresses why low income and medically underserved populations that work, reside, attend school, and play in environmentally contaminated neighborhoods have disproportionate adverse cognitive health outcomes.

Consistent with the Healthy People 2010 initiative, work from Dr. Hood’s laboratory over the past 10-years has contributed to the formulation of prevention and intervention strategies and public policy changes that have resulted in the reassessment by the EPA for maximum allowable ambient levels of polycyclic aromatic hydrocarbon emissions from industrial smokestacks. These public policy changes serve to decrease the adverse health effects associated with in utero environmental exposures in minority populations.  This is exemplified by his recent appointments to the Environmental Protection Agency’s Science Advisory Board Exposure and Human Health Committee and the National Environmental Justice Advisory Committee. Also, the National Institutes of Environmental Health Sciences Environmental Health Sciences Review Committee.

1. Hood, DB, Ramesh, A and Aschner, M (2009) Polycyclic Aromatic Hydrocarbons: Exposure from Emission Products and from Terrorist Attacks on US Targets-Implications for Developmental Central Nervous System Toxicity In: Handbook of the Toxicology of Chemical Warfare Agents. Vol. 3; Edited by Ramesh Gupta, Academic Press (London) pp.229-244.


2. Ford GD, Ford BD, Steele EC Jr, Gates A, Hood DB, Matthews MA, Mirza S, Macleish PR. (2008) Analysis of transcriptional profiles and functional clustering of global cerebellar gene expression in PCD3J mice. Biochem Biophys. Res. Commun. 2008 Dec 12;377(2):556-61.


3. Harris DL, Hood DB, and Ramesh A. (2008) Vehicle-dependent disposition kinetics of fluoranthene in Fisher-344 rats. Int. J. Environ. Res. Public Health 5(1):41-8.


4. Ramesh A, Inyang F, Lunstra DD, Niaz MS, Kopsombut PM, Jones KM, Hood DB, Hills ER, and Archibong AE. (2008) Alteration of fertility indices in adult F-344 rats by subchronic exposure to inhaled benzo(a)pyrene. Exp. Toxic. Pathol, 60(4-5):269-80.


5. McCallister MM, Maguire M, Ramesh R, Sheng L, Qiao A, Khoshbouei H, Aschner M, Ebner FF and Hood DB (2008) Prenatal Exposure to Benzo(a)pyrene Impairs Later-Life Cortical Neuronal Function. NeuroToxicology 29, 846-854.


6. Hood, D.B., Campbell, D., and Levitt, P. (2009) An Emerging Gene-Environment Interaction Model: Autism Spectrum Disorder Phenotypes Resulting from Exposure to Environmental Contaminants During Gestation. In; Developmental Neurotoxicology Research: Principles, Models, Techniques, Strategies and Mechanisms Vol. 1; Edited by Pessah, Isaac (Ed) John Wiley and Sons (London) (in press)


7. Stokes SC, Zokovitch J, Hood DB, and Close FT (2009) An Environmental Justice Community’s Approach to Risk Communication: Part I, The Plan. Journal of Health Care for the Poor and Underserved (in press)


8. Stokes SC, Zokovitch J, Hood DB, and Close FT (2009) An Environmental Justice Community’s Approach to Risk Communication Part II, The Implementation. Journal of Health Care for the Poor and Underserved (in press)