Androgen Modulation of Neurodegeneration in Dopamine Neurons

Summary

Principal Investigator: Rebecca L Cunningham
Abstract: PROBLEM: Parkinson's disease (PD) has a higher prevalence in the human male population. PD is characterized by motor dysfunction, rigidity, and bradykinesia. Current research suggests that gender plays a role in this condition, since males have a greater incidence of PD. It is believed that the underlying mechanism of PD involves oxidative stress leading to cellular apoptosis. In many peripheral cells and some neuronal cells, androgens have been shown to increase apoptosis. PURPOSE: The goal of these studies is to determine androgen's effects on dopaminergic cells following oxidative stress by using both in vitro and in vivo methods. The central hypothesis of this proposal is that androgens increase cellular vulnerability to oxidative stress-induced neurotoxicity in dopaminergic neurons. RESEARCH QUESTIONS: The first specific aim of this proposal is to determine the apoptotic signaling pathways activated by androgens in dopaminergic N27 cells following oxidative stress (hydrogen peroxide). The second specific aim is designed to evaluate the effects of androgens on estrogen-mediated neuroprotection in dopaminergic N27 neurons following oxidative stress. These aims will be accomplished through in vitro molecular studies with and without the presence of astroglia cells and the androgen receptor antagonist, hydroxyflutamide. Lastly, the third specific aim will characterize the in vivo effects of androgens on tyrosine hydroxylaseexpression, neuronal death, and motor behavior in aged male rats exposed to 6-OHDA, which induces oxidative stress and apoptosis in the substantia nigra and striatum. In vivo hormone treatment groups will consist of gonadectomized aged males, gonadally intact aged males, and gonadectomized aged males plus replacement androgen (testosterone or dihydrotestosterone) for either a chronic (3 months) or acute (1 week) treatment time length prior to 6-OHDA lesion. Immunocytochemical and behavioral techniques will be used to accomplish this aim. OUTCOMES: This study will provide basic knowledge on how androgens modulate dopaminergic cellular vulnerability to oxidative stress. Ultimately, this knowledge can be used to provide a foundation to understanding the mechanisms underlying sex differences in neurodegenerative disorders. PHS 416-1 (Rev. 10/05) Page 2 Number pages consecutively at the bottom throughout Form Page 2 the application. Do not use suffixes such as 2a, 2b NAME OF APPLICANT (Last, first, middle initial) Kirschstein-NRSA Individual Fellowship Application Cunningham, Rebecca, L. (To be completed by applicant- follow PHS416-1 instructions) 20. GOALS FOR KIRSCHSTEIN-NRSA FELLOWSHIP TRAINING AND CAREER The training goals of this fellowship include learning scientific approach, troubleshooting, manuscript preparation, and presentation skills. I believe these goals are critical in maturing as a scientist. As a researcher it is of utmost importance to have the ability to not only design and perform an experiment, but to also have the ability to troubleshoot potential problems. The experiments contained within this proposal have been chosen for their ability to test the hypothesis and extend my knowledge in androgen's mechanisms of action by utilizing different experimental techniques and model systems. As a researcher it is imperative to answer "the question." By having a broad knowledge of the tools and techniques available in the scientific community, the reliability of the data obtained is improved. The skills I wish to acquire while undertaking this proposal include Western blot analysis, immunocytochemistry, motor behavior analysis, and stereotaxic surgery. In addition, I wish to expand my knowledge of behavioral studies into the neurodegenerative field of study and determine what impact androgens have on neurodegeneration. 21. ACTIVITIES PLANNED UNDER THIS AWARD: instructions.) Year Research First 80% Second 90% Third 90% Fourth Fifth Approximate percentage of proposed award time in activities identified below. (See Course Work Teaching Clinical 20% 0% 0% 10% 0% 0% 10% 0% 0% PREDOCTORAL FELLOWSHIPS ONLY MD/PhD FELLOWSHIPS ONLY Sixth Briefly explain activities other than research and relate them to the proposed research training. The applicant will participate in several workshops offered by UTHSCSA that include grant and manuscript writing courses. The applicant has been and plans to continue participating in the weekly department seminars and journal clubs to expand her knowledge beyond her field of expertise. During the first year of the fellowship the applicant will take a 1 semester course on Biology of Aging, which is offered by the Department of Pharmacology. 22. TRAINING SITE(S) (organization, city, state) University of Texas Health Science Center-San Antonio, Texas 23. HUMAN EMBRYONIC STEM CELLS Kl No Q Yes If the proposed project involves human embryonic stem cells, list below the registration number of the specific cell line(s) from the following list: http://stemcells.nih.qov/reqistrv/index.asp. Use continuation pages as needed. If a specific line cannot be referenced at this time, include a statement that one from the Registry will be used. Cell Line PHS 416-1 (Rev. 10/05) Page 3 Form Page 3 Kirschstein-NRSA Individual Fellowship Application NAME OF APPLICANT (Last, first, middle initial) Table of Contents Cunningham, Rebecca, L. Page Numbers (Number pages consecutively at the _ _ bottom throughout the application. Section 1 - Applicant Do not use suffixes such as6a, 6b.) Face Page 1 Sponsor's Contact Information, Description (Form Page 2) 2 Training &Career Goals, Activities Planned Under This Award, Training Site, Human Embryonic Stem Cells (Form Page 3) 3 Table of Contents (Form Page 4) 4 Biographical Sketch - Applicant/Fellow (Not toexceed four pages) 5-6 Previous Research Experience (Form Page 5) 7-9 Research Training Plan Introduction to Revised Application (not to exceed 1page) A. Specific Aims TV. ^ 10 B. Background/Significance !(......(Not to exceed 10pages) J 11 C. Preliminary Studies/Progress Report ../T | 12 D. Research Design andMethods ).. ^ 13 E. Human Subjects (Required if Item 9 on the Face Page is marked "Yes") 20 Protection of Human Subjects (Required if Item 9 on the Face Page is marked "Yes") - Data and Safety Monitoring Plan (Required if Item 9 on the Face Page is marked "Yes" and a Phase I, II, or III clinical trial is proposed - Inclusion of Women and Minorities (Required if Item 9 on the Face Page is marked "Yes" and is Clinical Research) - Targeted/Planned Enrollment Table (for new and continuing clinical research studies) - Inclusion of Children (Required if Item 9 on the Face Page is marked "Yes") - F. Vertebrate Animals (Required if Item 10on the Face Page is marked "Yes") 20 G. Literature Cited 20 H. Resource Sharing 24 I. Respective Contributions 24 J. Selection of Sponsor and Institution 24 K. Responsible Conduct of Research 24 Section 2 - Sponsor's/Co-Sponsor's Information Biographical Sketch-Sponsor 25 Research Support Available 29 Previous Trainees 31 Training Plan, Environment, Research Facilities 31 Number of Fellows/Trainees to be Supervised 32 Applicant's Qualifications and Potential 32 Checklist (Completed by Fellow/Applicant &Sponsoring Institution) 33 Section 3 - References (Minimum of 3) (See instructions for submission of references.) List full name, institution, and department of individuals submitting reference letters. 1) Marilyn Y. McGinnis, Ph.D., UTHSCSA, Pharmacology 2) William P. Clarke, Ph.D., UTHSCSA, Pharmacology 3) J. Randy Strong, Ph.D., UTHSCSA, Pharmacology Other Items (list): Personal Data Page for Fellowship Applicants Section 4 - Appendix (5 collated sets. Nopage numbering necessary. Not to exceed 3 publications;2 for predoctoral candidates.) E3 Check if Appendix is included PHS 416-1 (Rev. 10/05) Page 4 Form Page 4
Funding Period: ----------------2008 - ---------------2011-
more information: NIH RePORT

Top Publications

  1. pmc Androgen receptors, sex behavior, and aggression
    Rebecca L Cunningham
    Department of Pharmacology and Neuroscience, University of North Texas Health Science Centre at Fort Worth, Fort Worth, TX 76107, USA
    Neuroendocrinology 96:131-40. 2012
  2. pmc Oxidative stress defines the neuroprotective or neurotoxic properties of androgens in immortalized female rat dopaminergic neuronal cells
    Shaletha Holmes
    PhD, Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3400 Camp Bowie Boulevard, Fort Worth, Texas 76107 2699
    Endocrinology 154:4281-92. 2013
  3. pmc Androgens induce dopaminergic neurotoxicity via caspase-3-dependent activation of protein kinase Cdelta
    Rebecca L Cunningham
    Department of Pharmacology and the Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229, USA
    Endocrinology 150:5539-48. 2009
  4. pmc Androgens exacerbate motor asymmetry in male rats with unilateral 6-hydroxydopamine lesion
    Rebecca L Cunningham
    Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107, USA
    Horm Behav 60:617-24. 2011

Scientific Experts

Detail Information

Publications5

  1. pmc Androgen receptors, sex behavior, and aggression
    Rebecca L Cunningham
    Department of Pharmacology and Neuroscience, University of North Texas Health Science Centre at Fort Worth, Fort Worth, TX 76107, USA
    Neuroendocrinology 96:131-40. 2012
    ..Knowledge of the mechanisms for androgens' effects on behaviors through the androgen receptor will guide future studies in elucidating male reproductive and aggressive behavior repertoires...
  2. pmc Oxidative stress defines the neuroprotective or neurotoxic properties of androgens in immortalized female rat dopaminergic neuronal cells
    Shaletha Holmes
    PhD, Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3400 Camp Bowie Boulevard, Fort Worth, Texas 76107 2699
    Endocrinology 154:4281-92. 2013
    ..Overall, our results indicate that androgens are neuroprotective when oxidative stress levels are minimal, but when oxidative stress levels are elevated, androgens exacerbate oxidative stress damage. ..
  3. pmc Androgens induce dopaminergic neurotoxicity via caspase-3-dependent activation of protein kinase Cdelta
    Rebecca L Cunningham
    Department of Pharmacology and the Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229, USA
    Endocrinology 150:5539-48. 2009
    ..These results support a neurotoxic consequence of testosterone on dopaminergic neurons and may provide insight into the gender bias found in PD...
  4. pmc Androgens exacerbate motor asymmetry in male rats with unilateral 6-hydroxydopamine lesion
    Rebecca L Cunningham
    Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107, USA
    Horm Behav 60:617-24. 2011
    ..Collectively, the data support the hypothesis that androgens may underlie the gender bias observed in PD...