~Oral Presentations~

• Ryan Herringa, MD, PhD (Click here to view presentation)
  Sleep patterns in the rhesus monkey: Links to physiological and psychological traits
• Jennifer Joeyen-Waldorf, BS (Click here to view presentation)
  Is the SERT knock-out mouse depressed? A revised behavioral and transcriptome approach
• Carissa A. Low, PhD (Click here to view presentation)
  Chronic life stress, cardiovascular reactivity, and subclinical cardiovascular disease in adolescents
• Debra M. Montrose, PhD (Click here to view presentation)
  Premorbid function and prodromal symptoms in young genetic high-risk relatives
• David Volk, MD, PhD (Click here to view presentation)
  Endocannabinoid signaling in the prefrontal cortex in schizophrenia: Role of Group I Metabotropic Glutamate Receptors

Presenter: Ryan Herringa, MD, PhD
Education: University of Wisconsin, Madison
Current Position: Resident
Principal Area of Research Interest: Pediatric sleep, anxiety, and traumatic stress
Current Research Support: None
Mentor(s): Ron Dahl, MD; Judy Cameron, PhD; Mary Phillips, MD; Neal Ryan, MD

Sleep patterns in the rhesus monkey: Links to physiological and psychological traits
Author(s): Herringa R, Ryan N, Dahl R, Cameron J
Affiliation(s): Department of Psychiatry, University of Pittsburgh School of Medicine

Study: Sleep problems often co-occur in patients with anxiety disorders or depression and are hallmark symptoms of these illnesses. We propose to use a rhesus monkey model to examine potential links between anxiety-like behaviors and sleep patterns. This model offers advantages of biological and behavioral similarities to humans, at the same time allowing for more detailed analyses in a controlled environment. The aims of this pilot study are: (1) To validate actigraphic measures of sleep-like patterns in the monkey, and (2) conduct a preliminary analysis of potential links between sleep-like patterns and anxious behaviors. We hypothesize that monkeys showing high levels of anxious behavior will tend to have poorer sleep quality.

Methods: 10 adult female rhesus monkeys were housed indoors on a 12h light/dark schedule. We collected actigraphy data from these monkeys using Actical accelerometers (Respironics, Inc, Phoenix AZ). We then tested multiple analytic parameters to define sleep-like patterns and compared to these to behaviorally-identified sleep from nighttime (infrared) and daytime video recordings. Using the optimal actigraphic sleep parameters, we then performed correlations between ‘sleep’ characteristics (e.g., latency to sleep, sleep duration, etc) and various forms of anxious behavior as determined in the Human Intruder Paradigm (HIT).

Results: Optimal actigraphy parameters for defining sleep-like patterns in monkeys differ substantially from humans. We found a duration of 12 minutes of 0 activity counts best matches behavioral sleep, showing the highest combination of sensitivity and specificity across day and night. Using Spearman’s rank correlation, we found that vigilant behavior was significantly correlated (r=0.59, p=0.04) with number of wake bouts during the night and inversely correlated with sleep efficiency.

Conclusion: Ideal parameters for defining actigraphic sleep in monkeys differ markedly from humans, likely due to the capability of monkeys to sit very still. We find preliminary evidence that anxious/vigilant behaviors are linked to poorer sleep quality in the monkey.

Significance: This study provides the first validation of actigraphic sleep measures in the monkey and provides hints that anxious temperament and poor sleep quality are linked in this animal model. This pilot is part of a larger planned study in which we hope to examine links between early anxiety and sleep patterns over puberty.

Funding Source(s): RO1 MH62568 and P60 AA010760 (PI: Judy Cameron, PhD), R24 MH067346 (PI: Ronald Dahl, MD)

Presenter: Jennifer Joeyen-Waldorf, BS
Education: Carnegie Mellon University
Current Position: Graduate Student Researcher
Principal Area of Interest: Major depression, amygdala, serotonin, serotonin transporter, animal models, unpredictable chronic mild stress, stress, mood disorders
Current Research Support: NIMH R01 MH 077159 (PI: Etienne Sibille, PhD) Mentor: Etienne Sibille, PhD

Is the SERT knock-out mouse depressed? A revised behavioral and transcriptome approach
Authors: Joeyen-Waldorf J¹, Edgar N2, Sibille E²
Affiliation(s): ¹Department of Neuroscience, University of Pittsburgh; ²Department of Psychiatry, University of Pittsburgh School of Medicine

Study: Vulnerability to develop Major Depressive Disorder (MDD) is modulated by a polymorphism in the human serotonin transporter (SERT) gene. A similar increased anxiety-like phenotype is observed in SERT knock-out mice. To address the current ambiguity as to the “depressive” quality of the SERT-KO phenotype, we hypothesized that: 1) A panel of pharmacologically-validated tests measuring anxiety-like, depressive-like and anhedonia-like behavior and acute antidepressant (AD) pharmacological efficacy will elucidate the nature of the SERT-KO emotional phenotype, and 2) Gene transcript changes between SERT-KO and wildtype (WT) will be similar to those measured in human MDD patients relative to control.

Methods: Three cohorts of C57 SERT WT and KO mice (N=10-20 per group) were tested in a panel of “emotion-related” behavioral tests. mRNAs extracted from SERT WT and KO mouse amygdala (AMY) and anterior cingulate (ACG) were hybridized to Affymetrix microarray chips (N=5 per group). Gene expression changes (p<.05, at least 20% change) between WT and KO were compared with gene expression changes from an existing human MDD and Control dataset. Microarray gene expression changes were validated by qPCR in mouse and human.

Results: Our results suggest that: 1) SERT-KO mice show increased “emotion-related” behavior in tests of anxiety-like behavior (open field, elevated plus maze), and depressive-like or anhedonia-like behavior (novelty suppressed feeding, sucrose preference test) but no change in acute tests of AD efficacy (forced swim test, tail suspension test), and 2) Some gene transcript changes (N=4-9) are conserved between the SERT-KO and human MDD (in amygdala and anterior cingulate gyrus), as measured by microarray and confirmed by qPCR. Many of the genes (such as adenylate cyclase) are related to neuronal signaling.

Conclusions: A panel of “emotion-related” behavioral tests suggests that the SERT KO mouse displays a behavioral phenotype that mimics symptoms of human MDD. Limited conserved expression changes between SERT KO/WT and human MDD/Control provide candidate genes for further studies. These common changes in gene expression suggest that the “depressive” phenotypes in mouse and human share molecular and cellular mechanisms.

Significance: This research provides support for the role of the SERT KO as a valid model to investigate the neurobiology of MDD and factors of vulnerability to develop MDD.

Funding Source(s): R01 MH 077159 (PI: Etienne Sibille, PhD).

Presenter: Carissa A. Low, PhD
Education: University of California Los Angeles
Current Position: Postdoctoral Scholar
Principal Area of Research Interest: Behavioral medicine
Current Research Support: NIMH T32 MH018269 (PI: Paul Pilkonis, PhD)
Mentor(s): Karen Matthews, PhD; Anna Marsland, PhD

Chronic life stress, cardiovascular reactivity, and subclinical cardiovascular disease in adolescents
Author(s): Low CA¹, Salomon K², Matthews KA¹
Affiliation(s): ¹Department of Psychiatry, University of Pittsburgh School of Medicine, ²Department of Psychology, University of South Florida

Study: Although cardiovascular disease generally manifests in adulthood, its pathogenesis begins in early life. Biological stress response systems also mature during adolescence, and exposure to chronic life stress during this sensitive developmental stage may be especially pernicious for adult health. The goal of the current study was to examine both cross-sectional and longitudinal relationships between chronic life stress, cardiovascular reactivity to laboratory stressors, and a marker of subclinical atherosclerosis in a multiethnic sample of adolescents.

Methods: Participants were 158 healthy adolescents (mean age = 14.5 at Time 1; 50.7% female, 50.2% Black) who completed self-report measures of chronic negative life stress as well as assessments of heart rate and blood pressure reactivity to acute laboratory stressors at two timepoints, approximately 3.3 years apart. At Time 2, carotid intima-media thickness (IMT), a measure of subclinical atherosclerosis, was also measured using B-mode ultrasonography.

Results: In hierarchical regression models adjusting for demographic variables and body mass index, chronic negative life stress at Time 2 was associated with greater diastolic blood pressure (DBP) reactivity to stress (β = .18, p = .016), and this heightened DBP reactivity was marginally associated with greater IMT (β = .14, p = .095). Moreover, a trajectory of increasing life stress from Time 1 to Time 2 was accompanied by a trajectory of increasing cardiovascular reactivity (β’s = .14 to .20, p < .05), and increasing DBP reactivity over time was also positively associated with IMT (β = .24, p = .03). Chronic life stress was not directly related to IMT.

Conclusion: Exposure to increasing levels of chronic, negative life stress during adolescence may be reflected in unhealthy changes in physiological stress reactivity. Heightened blood pressure reactivity to acute stressors is associated with greater IMT in healthy adolescents.

Significance: Adolescents exposed to chronic, negative stressors that worsen over time may be at risk for cardiovascular morbidity and represent an important target for early prevention efforts.

Funding Source: NHLBI grant R01 HL25767 (PI: Karen Matthews, PhD), NIMH grant T32 MH018269 (PI: Paul Pilkonis, PhD), and the John D. and Catherine T. MacArthur Foundation Research Network on Socioeconomic Status and Health.

Presenter: Debra M. Montrose, PhD
Education: University of Pittsburgh
Current Position: Research Program Administrator
Principal Area of Research Interest: Schizophrenia and High-risk Research
Current Research Support: NIMH R01 MH064023 (PI: Matcheri Keshavan, MD), P50 MH084053 (PI: David Lewis, MD)
Mentor: Matcheri Keshavan, MD

Premorbid function and prodromal symptoms in young genetic high-risk relatives
Author(s): Montrose DM¹, Mermon D¹, Miewald J¹, Eack S², Prasad K¹, Bangalore S¹, Diwadkar V ^{1, 3}, Abela M³, Benitez CZ³, Rajan U³, Rajarethinam R³, Keshavan MS^1,3
Affiliation(s): ¹Department of Psychiatry, University of Pittsburgh School of Medicine, ²Department of Social Work, University of Pittsburgh, ³Wayne State University, Detroit, MI

Study: Subthreshold negative symptoms and/or attenuated and brief-lasting intermittent psychotic symptoms are characteristic of the prodromal period before the onset of the psychotic phase. Since the prodrome, as currently defined, has a high rate of conversion to psychosis, it is important to predict the prodrome. Premorbid impairments, which precede the prodromal symptoms, might be the best predictors, but no studies to our knowledge have addressed this question. Studies of young relatives at high genetic risk for schizophrenia (HR) provide a valuable opportunity to examine this question.

Methods: Participants in the current analyses includes 56 first-degree relatives age 12 to 22 of an individual with schizophrenia or schizoaffective disorder. Diagnostic and clinical assessments were administered to determine Axis I psychopathology, premorbid functioning, prodromal symptoms, and general behavior.

Results: Significant relations were found between childhood premorbid functioning and prodromal symptomatology in HR subjects at baseline. Subsequent longitudinal growth curve analyses indicated that internalizing and externalizing behavior problems during childhood, but not maladjustment were significantly predictive of greater growth in prodromal symptoms over time.

Conclusion: This study provides the first evidence of an association between childhood premorbid functioning and prodromal symptoms. We also observed an association between childhood behavioral problems and growth in prodromal symptoms during follow-up.

Significance: This study highlights the potential value of premorbid functioning for predicting prodromal symptoms to “close in” on the eventual prediction of psychosis in genetically at-risk individuals. Premorbid maladjustment and behavior problems in high risk individuals is a potential target for early identification and intervention. Longitudinal data will help to study the relationship between premorbid difficulties, prodromal symptoms and eventual conversion to psychosis in genetically vulnerable individuals.

Funding Source(s): NIMH grants R01 MH064023 (PI: Matcheri Keshavan, MD) and P 50 MH045156 (PI: David Lewis, MD).

Presenter: David Volk, MD, PhD
Education: University of Pittsburgh
Current Position: Assistant Professor
Principal Area of Research Interest: Schizophrenia Current Research Support: NIMH K08 MH084016, (PI: David Volk, MD, PhD)
Mentor: David Lewis, MD

Endocannabinoid signaling in the prefrontal cortex in schizophrenia: Role of Group I Metabotropic Glutamate Receptors
Author(s): Volk DW¹, Eggan SM¹, Lewis DA ^1,2
Affiliation(s): ¹Department of Psychiatry, University of Pittsburgh School of Medicine, ²Department of Neuroscience, University of Pittsburgh

Study: Cannabis use is associated with worsening of prefrontal cortex (PFC)-related cognitive deficits in schizophrenia. Cognitive deficits in schizophrenia are linked to reduced GABA signaling in the PFC, and cannabinoid 1 receptor (CB1R) activation reduces GABA release. Thus, cannabis use may worsen cognitive deficits in schizophrenia by activating the CB1R which further impairs GABA signaling. Lower CB1R levels have been reported in the PFC in schizophrenia. However, do lower CB1R levels reflect an overall deficiency in eCB signaling in the disease, or are CB1R levels downregulated in response to excessive eCB signaling? Discriminating between these possibilities requires knowledge of the eCB ligands that bind to the CB1R. For example, the eCB 2-arachidonoylglycerol (2-AG) is synthesized by diacylglycerol lipase (DAGL) and degraded by monoglyceride lipase (MGL). Determining the levels of DAGL and MGL may help elucidate the status of 2-AG signaling in schizophrenia. Furthermore, alterations in group I metabotropic glutamate receptors (mGluR1α and mGluR5), which initiate the eCB signaling cascade, could also lead to altered 2-AG signaling.

Methods: Postmortem brain tissue from PFC area 9 from 42 subjects with schizophrenia and matched control subjects was processed by quantitative PCR to quantify relative mRNA levels for DAGL, MGL, mGluR1α, mGluR5, and other important eCB markers.

Results: No differences in mRNA levels for 2-AG synthesizing and metabolizing enzymes were found in the PFC in schizophrenia, but higher levels of mGluR1α mRNA were found in schizophrenia. These results were confirmed using multiple primer sets and did not appear to be attributable to demographic variables or treatment effects.

Conclusion: These results suggest that alterations in eCB signaling in schizophrenia may be principally occurring at the level of the CB1R. Elevated signaling through mGluR1α receptors may increase 2-AG signaling, resulting in a further deleterious reduction in GABA neurotransmission in the PFC in schizophrenia.

Significance: Alterations in eCB signaling in the PFC in schizophrenia, including increased expression of CB1R and mGluR1α, may worsen GABA signaling in the PFC and lead to further impairments in cognition in schizophrenia.

Funding Source: NIMH K08 MH084016 (PI: David Volk, MD, PhD).