Our lab is interested in the effects of neurotrophin signaling on the onset and progression of neurodegenerative diseases. A current aim of our research is to elucidate signaling cascades mediated by the p75 neurotrophin receptor (p75NTR) in dopaminergic neurons, a cell population that is vulnerable to oxidative stress and progressive neurodegeneration in individuals with Parkinson's disease. We use a variety of research methods in molecular biology to investigate the effects of p75NTR signaling on neurite degeneration and apoptosis of dopaminergic neurons in both cell culture and animal models of Parkinson's disease.
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Neurodegenerative disorders are diseases resulting from the progressive deterioration or death of cells within the nervous system. Parkinson’s disease (PD) is the second most common neurodegenerative disorder after Alzheimer’s disease and is a major cause of disability among the elderly, affecting an estimated 1.5% of individuals over the age of 65 globally. In the nervous system of individuals with PD, a group of neurons that communicate using the neurotransmitter dopamine begins to progressively degenerate. During early stages of PD, the deterioration of these dopaminergic neurons begins at the tips of their axons, the long threadlike projections that neurons use to send outgoing signals to other cells. In a process termed axonal degeneration, the long axons become dysfunctional and fragmented. The dopaminergic neurons also begin to undergo oxidative stress, a condition in which toxic and reactive molecules accumulate and interfere with the function of proteins, lipids, and DNA within the cells. The damage continues to spread to the round cell body of the neurons, and the neurons eventually die. The progressive death of dopaminergic neurons leads to a variety of debilitating motor and cognitive impairments in PD patients. Unfortunately, current treatment options for PD are only palliative and do not impact final outcomes on cognition and mortality. Thus, there is an urgent need for research that reveals the molecular basis of neurodegeneration, thereby facilitating development of novel treatment strategies.
Although the set of causes of most neurodegenerative diseases are poorly understood, a protein termed the p75 neurotrophin receptor (p75NTR) has been implicated in neurodegeneration caused by multiple types of neurological conditions. For example, p75NTR signaling has been demonstrated to promote death of neurons in mice subjected to spinal cord crush, seizures, or stroke. Remarkably, inhibiting p75NTR signaling protects neurons from death caused by these injuries. A known mechanism through which p75NTR becomes activated is by its cleavage into smaller protein fragments that are released from the membrane to interact with other signaling molecules. Recently, our laboratory has obtained data indicating that dopaminergic neurons produce p75NTR and that cleavage of p75NTR is triggered when the neurons are subjected to oxidative stress. Thus, p75NTR signaling may play a critical role in promoting the degeneration of dopaminergic neurons in individuals with Parkinson’s disease. We are currently using a combination of cell line models and mouse models to evaluate the effects of p75NTR signaling on dopaminergic neurodegeneration associated with PD.
Although the set of causes of most neurodegenerative diseases are poorly understood, a protein termed the p75 neurotrophin receptor (p75NTR) has been implicated in neurodegeneration caused by multiple types of neurological conditions. For example, p75NTR signaling has been demonstrated to promote death of neurons in mice subjected to spinal cord crush, seizures, or stroke. Remarkably, inhibiting p75NTR signaling protects neurons from death caused by these injuries. A known mechanism through which p75NTR becomes activated is by its cleavage into smaller protein fragments that are released from the membrane to interact with other signaling molecules. Recently, our laboratory has obtained data indicating that dopaminergic neurons produce p75NTR and that cleavage of p75NTR is triggered when the neurons are subjected to oxidative stress. Thus, p75NTR signaling may play a critical role in promoting the degeneration of dopaminergic neurons in individuals with Parkinson’s disease. We are currently using a combination of cell line models and mouse models to evaluate the effects of p75NTR signaling on dopaminergic neurodegeneration associated with PD.
Methods
Examples of techniques used by our laboratory are listed below:
- Cardiac perfusion
- Tissue dissection (ie. hippocampus, cerebral cortex, superior cervical ganglia, cerebellum)
- Cryosectioning
- Immunofluorescence staining
- Confocal microscopy
- Cell culture (establishment of primary neuronal cultures from cerebral cortex, hippocampus, or superior cervical ganglia, as well as use of various cell lines)
- Spectrophotometric assays (ie. XTT assay for quantification of cell viability and metabolism; Bradford or BCA assay for protein estimation)
- Gel electrophoresis and western blot analysis
- PCR
- Intracranial drug administration
- Quantification of neurite degeneration in 2d culture systems
Contact InformationKRAEMER LAB
Shelby Center for Science and Technology Room 338 301 Sparkman Drive NW Huntsville, AL 35899 OFFICE Room 369P Shelby Center (256) 824-6272 [email protected] (same as [email protected]) |