Colleen Hegg, PhD

Director, Comparative Medicine & Integrative Biology Program and Associate Department Chair (CVM)
Pharmacology & Toxicology

Bio

My research program is exploring the interface between toxicology and stem cell biology. I am a trained neurotoxicologist. I investigated heavy metal neurotoxicity during my graduate studies. I joined Stan Thayer’s lab as a postdoctoral fellow and studied the adverse effects of opioids and cannabinoids in the hippocampus in the context of HIV-1 AIDS dementia complex. I entered the field of chemical senses in 2000 in Mary Lucero’s lab where I investigated the physiological responses of the olfactory epithelium to modulatory factors, gaining experience with a model of adult neurogenesis. I integrated these experiences combining toxicity studies with neuroregenerative models when I began my independent career. Recent projects in my lab examined how mature cells derived from human induced pluripotent stem cells (hiPSCs) were altered by the effects of environmental air pollutants (mold-produced toxicants and concentrated ambient particles. The underlying themes were to determine key signaling components that regulate stem cell maturation and to examine alterations in the identified signaling components following environmental exposure. I realized my passion was in nurturing the next generation of scientists, particularly minoritized students, and that I could have a bigger impact if I focused my time on graduate student mentoring. Thus, I became the director of the Comparative Medicine and Integrative Biology Graduate program in 2019.

Colleges

• College of Veterinary Medicine

Programs

• Environmental & Integrative Toxicological Sciences Training Program

Education

• PhD, Environmental Toxicology, University of Wisconsin–Madison ()
• BA, Chemistry, Kalamazoo College ()

Funding

• Neurogenesis and chronic cannabinoid exposure, National Institute on Drug Abuse (2013-01-01—2015-12-31)
• Purinergic Receptors in Olfactory System, National Institute on Deafness and Other Communication Disorders (2001-08-01—2004-07-31)
• Injury-Evoked Regeneration Mechanism in Olfactory System, National Institute on Deafness and Other Communication Disorders (2004-07-01—2011-06-30)
• Short-term biomedical research training program for veterinary students, Office of the Director (2002-08-01—2028-08-31)
• Neural stem cell susceptibility to ambient particulate matter over the lifespan, National Institute of Environmental Health Sciences (2012-08-07—2014-07-31)
• Interdisciplinary Training in Leadership and Animal Biosecurity (IT-LAB), National Institute of Food and Agriculture (2022-11-01—2027-10-31)

Works

• An endocannabinoid system is present in the mouse olfactory epithelium but does not modulate olfaction. Neuroscience (2015)
• Defects in neural stem cell proliferation and olfaction in Chd7 deficient mice indicate a mechanism for hyposmia in human CHARGE syndrome. Human Molecular Genetics (2009-06-01)
• Satratoxin G–Induced Apoptosis in PC-12 Neuronal Cells is Mediated by PKR and Caspase Independent. Toxicological Sciences (2008)
• Diminished blocking effect of acute lead exposure on high-threshold voltage-gated calcium currents in PC12 cells chronically exposed to the heavy metal. Neurotoxicology (1998-06-01)
• ATP Mediates Neuroprotective and Neuroproliferative Effects in Mouse Olfactory Epithelium following Exposure to Satratoxin G In Vitro and In Vivo. Toxicological Sciences ()
• ATP differentially upregulates fibroblast growth factor 2 and transforming growth factor alpha in neonatal and adult mice: effect on neuroproliferation. Neuroscience ()
• Activation of Human Microglial Cells by HIV-1 gp41 and Tat Proteins. Clinical Immunology ()
• Activation of Purinergic Receptor Subtypes Modulates Odor Sensitivity. The Journal of Neuroscience ()
• Activation of purinergic receptors induces proliferation and neuronal differentiation in Swiss Webster mouse olfactory epithelium. Neuroscience ()
• Acute exposure to inorganic lead modifies high-threshold voltage-gated calcium currents in rat PC 12 cells. Brain Research ()
• An IP3R3- and NPY-Expressing Microvillous Cell Mediates Tissue Homeostasis and Regeneration in the Mouse Olfactory Epithelium. PLoS ONE ()
• Calcium store‐mediated signaling in sustentacular cells of the mouse olfactory epithelium. Glia ()
• Cannabinoid receptor signaling induces proliferation but not neurogenesis in the mouse olfactory epithelium. Neurogenesis ()
• Chronic exposure to inorganic lead increases high-threshold voltage-gated calcium currents in rat pheochromocytoma (PC12) cells. Brain Research ()
• Diazepam inhibits HIV-1 Tat-induced migration of human microglia. Journal of Neurovirology ()
• Dopamine Reduces Odor- and Elevated-K⁺-Induced Calcium Responses in Mouse Olfactory Receptor Neurons In Situ. Journal of Neurophysiology ()
• Effect of IP3R3 and NPY on age-related declines in olfactory stem cell proliferation. Neurobiology of Aging ()
• Electrical Coupling in Sustentacular Cells of the Mouse Olfactory Epithelium. Journal of Neurophysiology ()
• Induction of temporally dissociated morphological and physiological differentiation of N1E-115 cells. Brain Research Bulletin ()
• Ionic conductances in sustentacular cells of the mouse olfactory epithelium. The Journal of Physiology ()
• Mechanisms of constitutive and ATP-evoked ATP release in neonatal mouse olfactory epithelium. BMC Neuroscience ()
• Microvillous cells expressing IP3 receptor type 3 in the olfactory epithelium of mice. European Journal of Neuroscience ()
• Monocytic cells secrete factors that evoke excitatory synaptic activity in rat hippocampal cultures. European Journal of Pharmacology ()
• Morphine inhibits human microglial cell production of, and migration towards, RANTES. Journal of Psychopharmacology ()
• NPY mediates ATP-induced neuroproliferation in adult mouse olfactory epithelium. Neurobiology of Disease ()
• Neuropeptide Y and extracellular signal-regulated kinase mediate injury-induced neuroregeneration in mouse olfactory epithelium. Molecular and Cellular Neuroscience ()
• Nickel Sulfate Induces Location-Dependent Atrophy of Mouse Olfactory Epithelium: Protective and Proliferative Role of Purinergic Receptor Activation. Toxicological Sciences ()
• PACAP Is Present in the Olfactory System and Evokes Calcium Transients in Olfactory Receptor Neurons. Journal of Neurophysiology ()
• Purinergic receptor activation evokes neurotrophic factor NPY release from mouse olfactory epithelial slices. The FASEB Journal ()
• Purinergic receptor antagonists inhibit odorant‐induced heat shock protein 25 induction in mouse olfactory epithelium. Glia ()
• β-Chemokines and human immunodeficiency virus type-1 proteins evoke intracellular calcium increases in human microglia. Neuroscience ()

Employment

• Associate Professor, Michigan State University (2006)