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Bio

Heather graduated with a BS in Microbiology with an emphasis in Biotechnology from Florida Atlantic University. She is a Life Science Research Professional that joined the Department of Psychiatry in 2000, exploring genetic markers in antidepressant treatment and smoking cessation, gene expression in Alzheimer’s disease transgenic mouse models, cytokine expression in primary microglia and microglial-hippocampal organotypic co-cultures, and organizing a database of mood disorders subjects across labs to facilitate collaboration. She recently shifted focus to clinical research and is excited to be involved with the human side of the DNA she has been studying. She is looking forward to contributing to the advance of treatment options for depression and other mood disorders.

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  • Stanford Accelerated Intelligent Neuromodulation Therapy for Treatment-Resistant Depression. The American journal of psychiatry Cole, E. J., Stimpson, K. H., Bentzley, B. S., Gulser, M., Cherian, K., Tischler, C., Nejad, R., Pankow, H., Choi, E., Aaron, H., Espil, F. M., Pannu, J., Xiao, X., Duvio, D., Solvason, H. B., Hawkins, J., Guerra, A., Jo, B., Raj, K. S., Phillips, A. L., Barmak, F., Bishop, J. H., Coetzee, J. P., DeBattista, C., Keller, J., Schatzberg, A. F., Sudheimer, K. D., Williams, N. R. 2020: appiajp201919070720

    Abstract

    New antidepressant treatments are needed that are effective, rapid acting, safe, and tolerable. Intermittent theta-burst stimulation (iTBS) is a noninvasive brain stimulation treatment that has been approved by the U.S. Food and Drug Administration for treatment-resistant depression. Recent methodological advances suggest that the current iTBS protocol might be improved through 1) treating patients with multiple sessions per day at optimally spaced intervals, 2) applying a higher overall pulse dose of stimulation, and 3) precision targeting of the left dorsolateral prefrontal cortex (DLPFC) to subgenual anterior cingulate cortex (sgACC) circuit. The authors examined the feasibility, tolerability, and preliminary efficacy of Stanford Accelerated Intelligent Neuromodulation Therapy (SAINT), an accelerated, high-dose resting-state functional connectivity MRI (fcMRI)-guided iTBS protocol for treatment-resistant depression.Twenty-two participants with treatment-resistant depression received open-label SAINT. fcMRI was used to individually target the region of the left DLPFC most anticorrelated with sgACC in each participant. Fifty iTBS sessions (1,800 pulses per session, 50-minute intersession interval) were delivered as 10 daily sessions over 5 consecutive days at 90% resting motor threshold (adjusted for cortical depth). Neuropsychological testing was conducted before and after SAINT.One participant withdrew, leaving a sample size of 21. Nineteen of 21 participants (90.5%) met remission criteria (defined as a score <11 on the Montgomery-Åsberg Depression Rating Scale). In the intent-to-treat analysis, 19 of 22 participants (86.4%) met remission criteria. Neuropsychological testing demonstrated no negative cognitive side effects.SAINT, an accelerated, high-dose, iTBS protocol with fcMRI-guided targeting, was well tolerated and safe. Double-blinded sham-controlled trials are needed to confirm the remission rate observed in this initial study.

    View details for DOI 10.1176/appi.ajp.2019.19070720

    View details for PubMedID 32252538

  • Attenuation of Antidepressant Effects of Ketamine by Opioid Receptor Antagonism Williams, N. R., Heifets, B. D., Blasey, C., Sudheimer, K., Pannu, J., Pankow, H., Hawkins, J., Birnbaum, J., Lyons, D. M., Rodriguez, C. I., Schatzberg, A. F. AMER PSYCHIATRIC PUBLISHING, INC. 2018: 1205–15

    View details for DOI 10.1176/appi.ajp.2018.18020138

    View details for Web of Science ID 000451749000012

  • Attenuation of Antidepressant Effects of Ketamine by Opioid Receptor Antagonism. The American journal of psychiatry Williams, N. R., Heifets, B. D., Blasey, C., Sudheimer, K., Pannu, J., Pankow, H., Hawkins, J., Birnbaum, J., Lyons, D. M., Rodriguez, C. I., Schatzberg, A. F. 2018: appiajp201818020138

    Abstract

    OBJECTIVE: In addition to N-methyl-d-aspartate receptor antagonism, ketamine produces opioid system activation. The objective of this study was to determine whether opioid receptor antagonism prior to administration of intravenous ketamine attenuates its acute antidepressant or dissociative effects.METHOD: In a proposed double-blind crossover study of 30 adults with treatment-resistant depression, the authors performed a planned interim analysis after studying 14 participants, 12 of whom completed both conditions in randomized order: placebo or 50 mg of naltrexone preceding intravenous infusion of 0.5 mg/kg of ketamine. Response was defined as a reduction ≥50% in score on the 17-item Hamilton Depression Rating Scale (HAM-D) score on postinfusion day 1.RESULTS: In the interim analysis, seven of 12 adults with treatment-resistant depression met the response criterion during the ketamine plus placebo condition. Reductions in 6-item and 17-item HAM-D scores among participants in the ketamine plus naltrexone condition were significantly lower than those of participants in the ketamine plus placebo condition on postinfusion days 1 and 3. Secondary analysis of all participants who completed the placebo and naltrexone conditions, regardless of the robustness of response to ketamine, showed similar results. There were no differences in ketamine-induced dissociation between conditions. Because naltrexone dramatically blocked the antidepressant but not the dissociative effects of ketamine, the trial was halted at the interim analysis.CONCLUSIONS: The findings suggest that ketamine's acute antidepressant effect requires opioid system activation. The dissociative effects of ketamine are not mediated by the opioid system, and they do not appear sufficient without the opioid effect to produce the acute antidepressant effects of ketamine in adults with treatment-resistant depression.

    View details for PubMedID 30153752

  • KETAMINE'S ANTIDEPRESSANT EFFECT IS BLOCKED BY A MU-OPIOID RECEPTOR ANTAGONIST IN HUMANS AND MICE Heifets, B. D., Williams, N., Sudheimer, K., Pankow, H., Blasey, C., Lyons, D., Schatzberg, A. F. LIPPINCOTT WILLIAMS & WILKINS. 2018: 343

    View details for Web of Science ID 000460106500197

  • Corticotropin-releasing factor 1 receptor haplotype and cognitive features of major depression. Translational psychiatry Davis, E. G., Keller, J., Hallmayer, J., Pankow, H. R., Murphy, G. M., Gotlib, I. H., Schatzberg, A. F. 2018; 8 (1): 5

    Abstract

    Corticotropin-releasing factor signaling through CRF receptor type 1 (CRF1) has been shown to contribute to learning and memory function. A haplotype of alleles T-A-T in a set of common polymorphisms in the gene encoding for CRF1(CRHR1) has been associated with both depression vulnerability and alterations in cognitive functioning. The present study investigated the relations between the TAT haplotype and specific symptoms of depression, self-reported ruminative behaviors, and neuropsychological performance on a learning and memory task. Participants were adults with major depression with and without psychotic features (N = 406). Associations were examined between TAT haplotype and endorsement of depression symptoms from diagnostic interviews, scores on the rumination response scale (RRS), and verbal memory performance on the California Verbal Learning Test-II (CVLT-II). All analyses included depression subtype, age, and sex as covariates; CVLT-II analyses also included evening cortisol levels. Across the entire sample, carriers of more copies of the TAT haplotype reported greater endorsement of the symptom describing difficulty concentrating and making decisions. In separate subsamples, TAT homozygotes had higher rumination scores on the RRS, both brooding and reflection subscales, and more TAT copies were associated with poorer CVLT-II performance in both total learning and free recall trials. These data demonstrate that the CRHR1 TAT haplotype is associated with cognitive features of depression including difficulty with decision-making, higher rumination, and poorer learning and memory. It will be important in future research to identify the specific molecular mechanisms for CRF1signaling that contribute to depression-related cognitive dysfunction.

    View details for PubMedID 29317606

    View details for PubMedCentralID PMC5802461

  • Response to Transdermal Selegiline Smoking Cessation Therapy and Markers in the 15q24 Chromosomal Region. Nicotine & tobacco research Sarginson, J. E., Killen, J. D., Lazzeroni, L. C., Fortmann, S. P., Ryan, H. S., Ameli, N., Schatzberg, A. F., Murphy, G. M. 2015; 17 (9): 1126-1133

    Abstract

    Current treatments for smoking cessation have limited efficacy. A potential pharmaceutical treatment for smoking cessation is selegiline, a selective and irreversible monoamine oxidase B inhibitor. A few clinical trials have been carried out using selegiline but the results have been mixed. We sought to determine if genetic markers in cholinergic loci in the 15q24 chromosomal region predict response to smoking cessation therapy with selegiline.We performed an 8-week double-blind, placebo-controlled clinical trial of the selegiline transdermal system (STS) in heavy smokers, with follow-up at weeks 25 and 52. Eight single nucleotide polymorphisms (SNPs) in the 15q24 region, which contains the genes for the nicotinic acetylcholine receptor subunits CHRNA5, CHRNA3, and CHRNB4, were investigated for association with treatment response.The CHRNB4 promoter SNP rs3813567 was associated with both point prevalence abstinence (PPA) and post-quit craving. Carriers of the minor C allele treated with selegiline showed lower rates of abstinence and higher levels of craving than selegiline-treated non-carriers, indicating that the rs3813567 C allele adversely affects abstinence in selegiline-treated smokers. This effect was not present among placebo-treated smokers. Selegiline-treated smokers with the CHRNA5 rs680244 GG genotype had lower post-quit craving, and unlike placebo-treated GG-carrying smokers, did not experience a post-quit increase in depressive symptoms.Variants in genes encoding cholinergic receptors affect abstinence, craving and mood in selegiline-treated smokers. Selegiline primarily affects dopamine levels in the brain, but cholinergic input affects nicotine-induced dopaminergic activity. These markers may have value in identifying those likely to respond to selegiline for smoking cessation.

    View details for DOI 10.1093/ntr/ntu273

    View details for PubMedID 25572450

  • ABCB1 (MDR1) predicts remission on P-gp substrates in chronic depression PHARMACOGENOMICS JOURNAL Ray, A., Tennakoon, L., Keller, J., Sarginson, J. E., Ryan, H. S., Murphy, G. M., Lazzeroni, L. C., Trivedi, M. H., Kocsis, J. H., Debattista, C., Schatzberg, A. F. 2015; 15 (4): 332-339

    Abstract

    The hypothesis that allelic variation in the multidrug resistance-1 (MDR1 or ABCB1) gene encoding the P-glycoprotein (P-gp) blood-brain barrier efflux pump is associated with remission and side effects was tested in chronic major depression patients treated with P-gp substrates. In 83 patients from the REVAMP trial, frequency of and time to remission as well as side effects was tested among genotype groups at 6 ABCB1 single nucleotide polymorphisms (SNPs). These six SNPs are significantly associated with remission and time to remission, with minor allele carriers on rs2235040 and rs9282564 attaining statistical significance after controlling for the other ABCB1 SNPs. The six ABCB1 SNPs are also significantly associated with the average side effects. However, here common homozygotes on rs2235040 and rs9282564 demonstrated significantly higher side effects after controlling for the effects of the other ABCB1 SNPs. These findings confirm and extend previous observations that minor alleles of two ABCB1 SNPs predict remission to treatment with substrates and demonstrate that common homozygotes on these SNPs experience greater side effects. Results point to the potential importance of ABCB1 variation for personalized medicine approaches to treating depression.The Pharmacogenomics Journal advance online publication, 9 December 2014; doi:10.1038/tpj.2014.72.

    View details for DOI 10.1038/tpj.2014.72

    View details for Web of Science ID 000358448500007

  • ABCB1 (MDR1) predicts remission on P-gp substrates in chronic depression. The pharmacogenomics journal Ray, A., Tennakoon, L., Keller, J., Sarginson, J. E., Ryan, H. S., Murphy, G. M., Lazzeroni, L. C., Trivedi, M. H., Kocsis, J. H., DeBattista, C., Schatzberg, A. F. 2014

    Abstract

    The hypothesis that allelic variation in the multidrug resistance-1 (MDR1 or ABCB1) gene encoding the P-glycoprotein (P-gp) blood-brain barrier efflux pump is associated with remission and side effects was tested in chronic major depression patients treated with P-gp substrates. In 83 patients from the REVAMP trial, frequency of and time to remission as well as side effects was tested among genotype groups at 6 ABCB1 single nucleotide polymorphisms (SNPs). These six SNPs are significantly associated with remission and time to remission, with minor allele carriers on rs2235040 and rs9282564 attaining statistical significance after controlling for the other ABCB1 SNPs. The six ABCB1 SNPs are also significantly associated with the average side effects. However, here common homozygotes on rs2235040 and rs9282564 demonstrated significantly higher side effects after controlling for the effects of the other ABCB1 SNPs. These findings confirm and extend previous observations that minor alleles of two ABCB1 SNPs predict remission to treatment with substrates and demonstrate that common homozygotes on these SNPs experience greater side effects. Results point to the potential importance of ABCB1 variation for personalized medicine approaches to treating depression.The Pharmacogenomics Journal advance online publication, 9 December 2014; doi:10.1038/tpj.2014.72.

    View details for PubMedID 25487678

  • BDNF and CREB1 genetic variants interact to affect antidepressant treatment outcomes in geriatric depression. Pharmacogenetics and genomics Murphy, G. M., Sarginson, J. E., Ryan, H. S., O'Hara, R., Schatzberg, A. F., Lazzeroni, L. C. 2013; 23 (6): 301-313

    Abstract

    Brain-derived neurotrophic factor (BDNF) is associated with antidepressant response on the cellular level, in animal models, and in clinical studies. A common variant in the BDNF gene results in a substitution of a methionine (Met) for a valine at the amino acid position 66. Previous studies reported that the Met variant results in enhanced response to antidepressant medications. These findings may be at odds with studies indicating that on a cellular level the Met variant impairs the secretion of BDNF.We examined the effects of BDNF single nucleotide polymorphisms (SNPs) in response to the antidepressants paroxetine and mirtazapine in a sample of 246 geriatric patients with major depression, treated in a double-blind, randomized, 8-week clinical trial. We also examined the effects of genetic variation at the BDNF-related loci neurotrophic tyrosine kinase receptor 2, cyclic AMP responsive element binding protein 1 (CREB1), and CREB binding protein. A total of 53 SNPs were genotyped.BDNF genetic variation had a significant effect on the efficacy of paroxetine, with patients carrying the Met allele showing impaired response. SNPs at the CREB1 locus, which encodes a transcription factor important in BDNF signaling, also predicted response to paroxetine. Furthermore, we found a significant gene-gene interaction between BDNF and CREB1 that affected response to paroxetine. Because BDNF has been associated with cognitive function, we tested the effects of BDNF SNPs on change in a wide variety of cognitive tests over the 8-week trial, but there were no significant effects of genotype on cognition.These results provide new evidence for the importance of the BDNF pathway in antidepressant response in geriatric patients. The negative effect of the Met66 allele on antidepressant outcomes is consistent with basic science findings indicating a negative effect of this variant on BDNF activity in the brain. Further, the effect of BDNF genetic variation on antidepressant treatment is modified by variation in the gene encoding the downstream effector CREB1.

    View details for DOI 10.1097/FPC.0b013e328360b175

    View details for PubMedID 23619509

  • Markers in the 15q24 Nicotinic Receptor Subunit Gene Cluster (CHRNA5-A3-B4) Predict Severity of Nicotine Addiction and Response to Smoking Cessation Therapy AMERICAN JOURNAL OF MEDICAL GENETICS PART B-NEUROPSYCHIATRIC GENETICS Sarginson, J. E., Killen, J. D., Lazzeroni, L. C., Fortmann, S. P., Ryan, H. S., Schatzberg, A. F., Murphy, G. M. 2011; 156B (3): 275-284

    Abstract

    Stopping smoking is difficult even with treatment. Many patients prescribed pharmacologic treatments for smoking cessation experience side effects or lack of efficacy. We performed a pharmacogenetic study of the efficacy and tolerability of bupropion and transdermal nicotine (TN), two treatments for smoking cessation. Samples were drawn from two studies. In the first study (Maintenance 1, MT1), 301 smokers received bupropion plus TN for 11 weeks, followed by 14 weeks of placebo or bupropion. In the second study (MT2), 276 smokers received bupropion and TN for 8 weeks. We focused on eight SNPs in the 15q24 region, which contains the genes for the nicotinic cholinergic receptor subunits CHRNA5, CHRNA3, and CHRNB4, and has previously been implicated in nicotine addiction and smoking cessation. Analyses of baseline smoking quantity (SQ) identified an association between SQ and both the functional CHRNA5 SNP rs16969968 (D398N) and the CHRNA3 SNP rs1051730 (Y215Y) in a combined cohort containing MT1 and MT2. An association between SQ and ethnicity was also identified in the combined cohort. Pharmacogenetic analysis showed a significant association between rs8192475 (R37H) in CHRNA3 and both higher craving after quitting and increased withdrawal symptoms over time in MT2. Two markers for point prevalence abstinence, CHRNA5 SNP rs680244 and CHRNB4 SNP rs12914008, were also identified in MT2, with the strongest findings at week 52. These results provide further support for the role of the CHRNA5/A3/B4 subunits in determining number of cigarettes smoked and response to smoking cessation therapy.

    View details for DOI 10.1002/ajmg.b.31155

    View details for Web of Science ID 000288332600003

    View details for PubMedID 21268243

  • ABCB1 ( MDR1) polymorphisms and antidepressant response in geriatric depression PHARMACOGENETICS AND GENOMICS Sarginson, J. E., Lazzeroni, L. C., Ryan, H. S., Ershoff, B. D., Schatzberg, A. F., Murphy, G. M. 2010; 20 (8): 467-475

    Abstract

    Variation in the ATP-binding cassette, subfamily B, member 1 transporter (ABCB1) (multidrug-resistance gene 1) gene has been investigated as a predictor of response to treatment with a variety of medications such as antiarrhythmics, chemotherapeutic agents, anti-HIV medications, and some psychotropics. The ABCB1 gene product, P-glycoprotein, affects the transport of drugs out of many cell types, including endothelial cells at the blood-brain barrier. We sought to determine if ABCB1 polymorphisms predict response to antidepressant treatment in geriatric patients.We compared the effects of ABCB1 genetic variation on the therapeutic response to paroxetine, a P-glycoprotein substrate, and to mirtazapine, which is not thought to be transported by ABCB1, in a sample of 246 elderly patients with major depression treated in a clinical trial setting. A total of 15 single nucleotide polymorphisms in the ABCB1 gene were assessed in each patient. Two of these ABCB1 single nucleotide polymorphisms were earlier reported to predict treatment response in patients prescribed with P-glycoprotein substrate antidepressants.The two earlier identified ABCB1 markers for antidepressant response predicted time to remission in our paroxetine-treated patients, but not in the mirtazapine-treated patients. These results replicate the published findings of others. If a Bonferroni correction for type I error is made, our results do not reach the criteria for statistical significance. However, the Bonferroni correction may be too conservative given the strong linkage disequilibrium among some of the markers and our aim to replicate the earlier published findings.Our study provides confirmation that certain ABCB1 polymorphisms predict response to substrate medications in geriatric patients.

    View details for DOI 10.1097/FPC.0b013e32833b593a

    View details for Web of Science ID 000279865400001

    View details for PubMedID 20555295

  • FKBP5 Polymorphisms and Antidepressant Response in Geriatric Depression AMERICAN JOURNAL OF MEDICAL GENETICS PART B-NEUROPSYCHIATRIC GENETICS Sarginson, J. E., Lazzeroni, L. C., Ryan, H. S., Schatzberg, A. F., Murphy, G. M. 2010; 153B (2): 554-560

    Abstract

    Genetic variation at the FKBP5 locus has been reported to affect clinical outcomes in patients treated with antidepressant medications in several studies. However, other reports have not confirmed this association. FKBP5 may regulate the sensitivity of the hypothalamic-pituitary-adrenal axis. We tested two FKBP5 single nucleotide polymorphisms (rs1360780 and rs3800373) in a sample of 246 geriatric patients treated for 8 weeks in a double-blind randomized comparison trial of paroxetine and mirtazapine. These two polymorphisms had previously been reported to predict efficacy in depressed patients treated with selective serotonin reuptake inhibitors such as paroxetine, and those treated with mirtazapine, an agent with both serotonergic and noradrenergic actions. However, we found no significant associations between these FKBP5 genetic variants and clinical outcomes. Neither mean Hamilton Depression Rating Scale scores nor time to remission or response were predicted by FKBP5 genetic variation. These results suggest that FKBP5 is unlikely to play a major role in determining antidepressant treatment outcomes in geriatric patients.

    View details for DOI 10.1002/ajmg.b.31019

    View details for Web of Science ID 000275377900023

    View details for PubMedID 19676097

    View details for PubMedCentralID PMC2897151

  • A beta peptide conformation determines uptake and interleukin-1 alpha expression by primary microglial cells NEUROBIOLOGY OF AGING Parvathy, S., Rajadas, J., Ryan, H., Vaziri, S., Anderson, L., Murphy, G. M. 2009; 30 (11): 1792-1804

    Abstract

    Microglia clear amyloid beta (Abeta) after immunization. The interaction of Abeta with the microglial cell surface also results in cytokine expression. Soluble oligomers and protofibrils of Abeta may be more neurotoxic than Abeta fibrils. We investigated the effects of oligomeric, protofibrillar and fibrillar Abeta40 and Abeta42 peptides on uptake and IL-1alpha expression by primary microglia. Abeta peptide assemblies were extensively characterized. Primary microglial cells were exposed to different Abeta40 and Abeta42 assemblies and IL-1alpha expression was quantified. To study uptake, microglial cells were exposed to different assemblies of Cy3-labeled Abeta. We found that Abeta42 and Abeta40 oligomers and fibrils induced IL-1alpha expression, but protofibrils did not. We also observed that all forms of Abeta42 (oligomer, protofibril and fibril) and Abeta40 fibrils were taken up by the microglial cells. These results demonstrate that microglial cells can take up non-fibrillar Abeta and that oligomeric peptide induces an inflammatory response. The uptake of oligomeric and protofibrillar Abeta by microglia merits further investigation as a potential means for removing these neurotoxic species from the brain.

    View details for DOI 10.1016/j.neurobiolaging.2008.01.011

    View details for PubMedID 18339452

  • Gene expression profile of the PDAPP mouse model for Alzheimer's disease with and without Apolipoprotein E NEUROBIOLOGY OF AGING Selwood, S. P., Parvathy, S., Cordell, B., Ryan, H. S., Oshidari, F., Vincent, V., Yesavage, J., Lazzeroni, L. C., Murphy, G. M. 2009; 30 (4): 574-590

    Abstract

    The APOE epsilon 4 allele is a strong risk factor for Alzheimer's disease (AD). However, the molecular basis for this effect remains unclear. We examined expression of approximately 12,000 genes and expressed sequence tags in the hippocampus and cortex of PDAPP (APP(V717)) mice modeling AD that show extensive amyloid beta (A beta) deposition, and in PDAPP mice lacking murine APOE expression, which show marked attenuation of A beta deposition in the brain. Wild type and APOE knockout animals were also examined. Expression levels were determined at the initial stage of A beta deposition, as well as in older animals showing extensive neuropathological changes. Fifty-four transcripts were identified using our statistical analysis as differentially regulated between the PDAPP and PDAPP/APOE ko mice, whereas 31 transcripts were classified as differentially regulated among PDAPP mice and WT animals, and seven transcripts were identified as regulated between the PDAPP/APOE ko animals and the APOE ko animals. Interestingly, many of the differentially regulated genes we detected can be related to biological processes previously shown to be important in AD pathophysiology, including inflammation, calcium homeostasis, cholesterol transport and uptake, kinases and phosphatases involved in tau phosphorylation and dephosphorylation, mitochondrial energy metabolism, protein degradation, neuronal growth, endoplasmic reticulum (ER) stress related proteins, antioxidant activity, cytoskeletal organization, and presenilin binding proteins. Regulated genes also included some not directly associated with AD in the past but likely to be involved in known AD pathophysiologic mechanisms, and others that may represent completely novel factors in the pathogenesis of AD. These results provide a global molecular profile of hippocampal and cortical gene expression during the initial and intermediate stages Abeta deposition, and the effects of APOE deletion on this process.

    View details for DOI 10.1016/j.neurobiolaging.2007.08.006

    View details for PubMedID 17904698

  • Microglia overexpressing the macrophage colony-stimulating factor receptor are neuroprotective in a microglial-hippocampal organotypic coculture system JOURNAL OF NEUROSCIENCE Mitrasinovic, O. M., Grattan, A., Robinson, C. C., Lapustea, N. B., Poon, C., Ryan, H., Phong, C., Murphy, G. M. 2005; 25 (17): 4442-4451

    Abstract

    Microglia with increased expression of the macrophage colony-stimulating factor receptor (M-CSFR; c-fms) are found surrounding plaques in Alzheimer's disease (AD) and in mouse models for AD and after ischemic or traumatic brain injury. Increased expression of M-CSFR causes microglia to adopt an activated state that results in proliferation, release of cytokines, and enhanced phagocytosis. To determine whether M-CSFR-induced microglial activation affects neuronal survival, we assembled a coculture system consisting of BV-2 microglia transfected to overexpress the M-CSFR and hippocampal organotypic slices treated with NMDA. Twenty-four hours after assembly of the coculture, microglia overexpressing M-CSFR proliferated at a higher rate than nontransfected control cells and exhibited enhanced migration toward NMDA-injured hippocampal cultures. Surprisingly, coculture with c-fms-transfected microglia resulted in a dramatic reduction in NMDA-induced neurotoxicity. Similar results were observed when cocultures were treated with the teratogen cyclophosphamide. Biolistic overexpression of M-CSFR on microglia endogenous to the organotypic culture also rescued neurons from excitotoxicity. Furthermore, c-fms-transfected microglia increased neuronal expression of macrophage colony-stimulating factor (M-CSF), the M-CSFR, and neurotrophin receptors in the NMDA-treated slices, as determined with laser capture microdissection. In the coculture system, direct contact between the exogenous microglia and the slice was necessary for neuroprotection. Finally, blocking expression of the M-CSF ligand by exogenous c-fms-transfected microglia with a hammerhead ribozyme compromised their neuroprotective properties. These results demonstrate a protective role for microglia overexpressing M-CSFR in our coculture system and suggest under certain circumstances, activated microglia can help rather than harm neurons subjected to excitotoxic and teratogen-induced injury.

    View details for DOI 10.1523/JNEUROSCI.0514-05.2005

    View details for Web of Science ID 000228702900025

    View details for PubMedID 15858070

  • Sleep and circadian abnormalities in a transgenic mouse model of Alzheimer's disease: A role for cholinergic transmission NEUROSCIENCE Wisor, J. P., Edgar, D. M., Yesavage, J., Ryan, H. S., McCormick, C. M., Lapustea, N., Murphy, G. M. 2005; 131 (2): 375-385

    Abstract

    The Tg2576 mouse model of Alzheimer's disease (AD) exhibits age-dependent amyloid beta (Abeta) deposition in the brain. We studied electroencephalographically defined sleep and the circadian regulation of waking activities in Tg2576 mice to determine whether these animals exhibit sleep abnormalities akin to those in AD. In Tg2576 mice at all ages studied, the circadian period of wheel running rhythms in constant darkness was significantly longer than that of wild type mice. In addition, the increase in electroencephalographic delta (1-4 Hz) power that occurs during non-rapid eye movement sleep after sleep deprivation was blunted in Tg2576 mice relative to controls at all ages studied. Electroencephalographic power during non-rapid eye movement sleep was shifted to higher frequencies in plaque-bearing mice relative to controls. The wake-promoting efficacy of the acetylcholinesterase inhibitor donepezil was lower in plaque-bearing Tg2576 mice than in controls. Sleep abnormalities in Tg2576 mice may be due in part to a cholinergic deficit in these mice. At 22 months of age, two additional deficits emerged in female Tg2576 mice: time of day-dependent modulation of sleep was blunted relative to controls and rapid eye movement sleep as a percentage of time was lower in Tg2576 than in wild type controls. The rapid eye movement sleep deficit in 22 month-old female Tg2576 mice was abolished by brief passive immunization with an N-terminal antibody to Abeta. The Tg2576 model provides a uniquely powerful tool for studies on the pathophysiology of and treatments for sleep deficits and associated cholinergic abnormalities in AD.

    View details for DOI 10.1016/j.neuroscience.2004.11.018

    View details for Web of Science ID 000227258400011

    View details for PubMedID 15708480

  • Analysis of neuronal gene expression with laser capture microdissection JOURNAL OF NEUROSCIENCE RESEARCH Vincent, V. A., DeVoss, J. J., Ryan, H. S., Murphy, G. M. 2002; 69 (5): 578-586

    Abstract

    The brain is a heterogeneous tissue in which the numbers of neurons, glia, and other cell types vary among anatomic regions. Gene expression studies performed on brain homogenates yield results reflecting mRNA abundance in a mixture of cell types. Therefore, a method for quantifying gene expression in individual cell populations would be useful. Laser capture microdissection (LCM) is a new technique for obtaining pure populations of cells from heterogeneous tissues. Most studies thus far have used LCM to detect DNA sequences. We developed a method to quantify gene expression in hippocampal neurons from mouse brain using LCM and real-time reverse transcriptase-polymerase chain reaction (RT-PCR). This method was optimized to permit histochemical or immunocytochemical visualization of nerve cells during LCM while minimizing RNA degradation. As an example, gene expression was quantified in hippocampal neurons from the Tg2576 mouse model for Alzheimer's disease.

    View details for DOI 10.1002/jnr.10329

    View details for Web of Science ID 000177745500002

    View details for PubMedID 12210823

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