Monday, October 19
Small Group Activity
Impromptu Networking- Rapidly Share Challenges and Expectations, Build New Connections (20 min.)
Photo Scavenger Hunt
If you indicated that you wanted to participate in the Photo Scavenger Hunt as a part of your registration for the retreat, you have been assigned to a team. To join your team meeting, click on your team number below.
Gissell Sanchez Ingrid Ward Will Birdsong
Raymond Adili Jess Anand Douglas McMillan
Julie Finnell Liz Jaeckel Jorge Iniguez-Lluhi
Claire Shudde James Teuber Kassidy Jungles
Colin Mansfield Ramkumar Mohan Shreeya Bakshi
Hoa Phan Ian Chronis Amanda France
Kelsey Kochan Chante Liu Ruchi Bhagat
Jiayu Wang Luis Lopez-Santiago Nathalie Momplaisir
Anne Lietzke Emily Jutkiewicz Emily Scott
David Jones Megan Wickens Brian Tran
Tracy Fetterly Taylor Piper Keith Olson
Naincy Chandan Anthony Garcia Debra Paris
Alina Morales. Tenzin Ngodup Rob Goldsmith
Erwin Arias-Hervert Arun Anantharam Jacob Ormes
Lori Isom Irina Zhang Nichelle Jackson
Postdoctoral Oral Presentations
Please complete an Oral Presentation Feedback form for each of the postdoctoral talks you attend. Your feedback will be passed on to our presenters. Based on the data, one speaker will be asked to present during a Wednesday seminar during the winter term.
Session 1 (2:05-2:25 PM)
Effects of dose cocaine on the rewarding properties of a drug-associate stimulus.
Drug-associated stimuli take on rewarding properties that promote drug-seeking, drug-taking, and relapse. We examined the extent to which the dose of cocaine influenced the rewarding properties of the cocaine-associated stimulus. First, rats underwent 10 Pavlovian conditioning sessions in which they received 10 cocaine deliveries (100, 320, or 560 ug/kg/inf) and 10 stimulus presentations according to a variable time 15 min schedule. Rats assigned to the experimental group received the cocaine deliveries and stimulus presentations together (Paired), whereas the control group received cocaine deliveries and stimulus presentations according to two separate clocks (Random). Next, we assessed the rewarding properties of the cocaine-associated stimulus across 42 days during which rats were allowed to respond for the stimulus alone. We found that the conditioned reinforcing properties of the stimulus depended on an interaction between the day of testing, conditioning history, and dose. We found a main effect of dose and a main effect of conditioning, such that rats that received Paired Pavlovian conditioning at higher doses of cocaine tended to emit a higher level of responses. Effect size analyses were used to examine the persistence of responding and revealed that rats that received Paired Pavlovian conditioning with 320 ug/kg/inf showed most robust rewarding properties. These findings demonstrate that cocaine-associated stimuli maintain prolonged drug-seeking, which underscores the importance of Pavlovian conditioning processes in drug abuse.
Evaluating the effects of continuous sugar drinking on demand in obesity prone and resistant rats
1.9 Billion adults worldwide are overweight or obese. The main cause of obesity is the consumption of foods high in fats and sugar, which have been documented to produce alterations in brain motivational systems that further enhance food intake. In addition, some individuals are more susceptible to weight gain; a phenotype that is found in both human and rodent populations. However, few studies have assessed the effects of high sugar diets on food motivation in rodent models of susceptibility to obesity. Here, we assessed potential baseline differences in motivation for liquid sucrose (1 molar) between obesity-prone and obesity-resistant rats, and the behavioral effects of long-term liquid sucrose consumption. We first adapted demand procedures used to assess relationships between price (i.e. work/reinforcements) and consumption of drugs like cocaine, for use with liquid sucrose. We verified that our demand procedure is sensitive to shifts in hunger and sucrose concentration, as expected. We then found that baseline demand for 1 molar sucrose is greater in obesity-prone vs. obesity-resistant rats. This difference is maintained after continuous ad libitum liquid sucrose consumption (6 weeks). In addition, in obesity-prone rats, sucrose consumption reduced motivation for 0.25 molar sucrose, but had no such effect in obesity-resistant rats. These data suggest that homeostatic regulation of sucrose intake is maintained in obesity-prone rats following prolonged sucrose consumption, but is disrupted in obesity-resistant rats. Ongoing studies are evaluating the effect of liquid sucrose deprivation. We expect that this will enhance demand for sucrose in both groups, with larger effects in obesity-prone vs. obesity-resistant rats.
Session 2 (2:25-2:45 PM)
Input specific alterations in excitatory transmission in the NAc core following junk-food diet consumption
Alterations in brain reward circuits, including the Nucleus Accumbens (NAc), contribute to over-eating and craving which drives the development and persistence of obesity. For instance, cue-triggered food-seeking is enhanced in obesity-prone rats and this behavior is mediated by calcium-permeable AMPA receptors (CP-AMPARs) in the NAc. AMPA-type glutamate receptors provide the main source of excitation to the NAc, a small portion of which are CP-AMPARs under basal conditions. Interestingly, eating a “junk-food” diet enhances NAc CP-AMPAR transmission in obesity-prone but not obesity-resistant rats. While this demonstrates an alteration in glutamatergic transmission in the NAc following “junk-food” consumption, it does not provide any information about the specific circuits altered. The NAc receives glutamatergic input from a wide variety of brain regions, including the medial prefrontal cortex (mPFC) and basolateral amygdala (BLA). However, whether junk-food induced increases in CP-AMPAR transmission are input specific is unknown. To dissect these circuits, we used whole-cell patch clamp recordings in combination with a viral optogenetic strategy to selectively record responses in either mPFC-to-NAc or BLA-to-NAc inputs. We found that eating junk-food enhanced CP-AMPAR transmission in mPFC-to-NAc inputs, but did not alter CP-AMPAR transmission in BLA-to-NAc inputs. Thus, junk-food induced enhancements in CP-AMPARs occur at specific inputs. As both regions are involved in the motivation for food-seeking, knowing how these circuits are differentially regulated helps guide our understanding of the neurobiology of craving.
Effect of Met-Enkephalin on Excitatory and Inhibitory Synaptic Transmission in the Mouse Anterior Cingulate Cortex
In this work, the hypothesis that met-enkephalin (mEnk) promotes excitatory thalamic input to L5 pyramidal neurons (Pyr) in the anterior cingulate cortex (ACC) by preferentially attenuating the release of GABA from local interneurons presumably expressing δ-opioid receptors was tested. Bilateral stereotaxic microinjections of AAV2-hSyn-ChR2-(H134R)-EYFP into the medial thalamus of 4-week old f/m C57/BL6j mice were performed. Two weeks post-surgery, mice were euthanized under isoflurane anesthesia and 250-300 μm acute coronal brain slices were prepared. Synaptic responses of Pyr were driven by flashing 488 nm light pulses of 1-5 ms duration and assessed with whole-cell patch clamp recordings. Excitatory and inhibitory synaptic currents (EPSC and IPSC) were isolated by alternating the holding potential between -65 and +5 mV, respectively. mEnk was perfused in the bath solution at a rate of 2 ml/min for 5-7 minutes. The effect of mEnk on the EPSC and IPSC was estimated by averaging 3-5 sweeps per condition and measuring the kinetics of the averaged traces. The data shows that mEnk differentially attenuates the release of glutamate and GABA in the ACC. The IC50 for the EPSC and IPSC are 0.1666 and 0.0516 μM, respectively. mEnk produced a reversible 2-fold increase in the EPSC/IPSC ratio at doses higher than 0.1 μM (P<0.05, n=6), accompanied by a 2-fold increase in the number of action potentials fired in response to threshold stimulation. Thus, mEnk facilitates glutamatergic transmission by inhibiting the release of GABA in the mouse ACC.
Session 3 (2:45-3:05 PM)
Finding (re)Purpose(d) [drugs] Working on a Computer During a Pandemic: A Virtual screening of FDA approved drugs at 48 classical and predicted viral drug sites
The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic requires treatments with rapid clinical translatability. Several drug repurposing studies have screened FDA-approved drugs in silico at a limited number of classical antiviral sites to decrease the time needed to enter clinical testing. We hypothesized that an extensive in-silico drug repurposing screen against all SARS-COV-2 proteins could 1) identify novel antiviral drugs and 2) help elucidate mechanisms of drug action. Using the docking software GOLD1 (web ref), we docked 1268 FDA-approved small-molecule drugs into 48 known or putative drug sites across 23 SARS-COV-2 crystal structures or homology models. We selected sites based on known antiviral drug sites (i.e., polymerase or protease active sites), co-crystallized ligands, computational analysis using MOE site finder1, or protein-protein interfaces based on the crystal structures. We then prioritized the virtual hits with known anti-SARS-COV-2 activity determined in vitro from a recent drug repurposing screen at UM3. Amprenavir, a known HIV protease inhibitor, docked well with a putative allosteric site on the SARS-COV-2 Spike (S) protein, which is responsible for viral entry. This proposed allosteric site is borders the Spike’s S2’ cleavage site, which a host protease must cut for viral entry. Further, this site contains multiple residues from the critical ‘fusion peptide’ domain used during viral entry. The next steps include validating key results in purified protein systems and in vitro testing of proposed drug combinations with predicted synergy based on predicted targets.
- Verdonk, M. L., Cole, J. C., Hartshorn, M. J., Murray, C. W., & Taylor, R. D. (2003). Improved protein-ligand docking using GOLD. Proteins: Structure, Function, and Bioinformatics, 52(4), 609-623.
- Molecular Operating Environment (MOE). Montreal, QC, Canada: Chemical Computing Group 2019.01
- Mirabelli, C., Wotring, J. W., Zhang, C. J., McCarty, S. M., Fursmidt, R., Kadambi, N. S., ... & Frum, T. (2020). Morphological Cell Profiling of SARS-CoV-2 Infection Identifies Drug Repurposing Candidates for COVID-19. bioRxiv.
How the most abundant immune cells in the blood secrete NETs and avoid too much of it?
Neutrophils, the most abundant innate immune cells in blood, are endowed with the ability to sense and migrate directionally towards chemical cues such as fMLF (a bacterial peptide), which are generated by damaged and inflamed tissues. fMLF activates and polarizes neutrophils, and stimulates the secretion of one of the key secondary chemoattractant, leukotriene B4 (LTB4), packaged in extracellular vesicles (EVs). These EVs relay the chemotactic signal to distant neutrophils thereby increasing neutrophil recruitment range and the immune response. Interestingly, the formation of LTB4-containing EVs which are generated from CD63-positive vesicles initiate at the nuclear envelope, where the LTB4 synthesis machinery resides. Here we show that both primary (fMLF) and secondary (LTB4) chemoattractants stimulate nuclear envelope budding, which is dependent on nSMase mediated ceramide generation. These buds are generated from the inner nuclear membrane (INM) as suggested by presence of the INM resident protein, lamin B receptor (LBR), at the periphery of LTB4-containing cytoplasmic vesicles.
During immune surveillance of exposed tissues, such as the eye and teeth, and under bacterial/viral infection in the body, neutrophils have been shown to release Neutrophil Extracellular Traps (NETs) – a process that also occurs during autoimmune diseases and cancer. PMA-induced suicidal NET release involves the rupture of neutrophils and dispersal of NETs composed of chromatin material studded with toxic enzymes. Here we show that LTB4-induced NET release neither accompanies cell lysis nor does it requires any machinery described for suicidal NET release. Rather, vital NET release is dependent on nSMase mediate nuclear envelop budding and uses the same machinery responsible for LTB4 secretion. Interestingly, we found that inhibition of lysosomal activity increases LTB4-induced NET release, suggesting that lysosomal biogenesis is a negative feedback pathway for NET release. These findings pride a mechanistic framework for NET release and help us to understand how neutrophils balance NET secretion to maintain immunological homeostasis.
Tuesday, October 20
"Strategic DEI Planning"
Zoom Meeting: https://umich-health.zoom.us/j/98027131323?pwd=cWRpZTdaKy92amRaY1lCekVCb...
Meeting ID: 980 2713 1323
Meeting ID: 929 8851 7254
"Self-Advocacy During and Beyond Your Training"
Virtual Poster Session
A google form has been created so that all poster presenters can receive feedback on their poster and presentation. All attendees are highly encouraged to complete a survey for each poster they visit. The data will be passed on to our presenters. We will not have any judging as a part of the poster session.
Group A (2:30-3 PM)
Acetylcholine and PACAP distinctly regulate catecholamine secretion in chromaffin cells
Identification and Characterization of PDZ‐RhoGEF as a Novel Target of Gαi
Identifying regulators of β2 adrenergic receptor sorting and signaling at the endosome
Positive Allosteric Modulation of the Mu Opioid Receptor in Brain Tissue
Feedback Regulation of Cannabinoid Receptor-1 Trafficking: Exploring the Differential Effects of Cannabinoid Ligands on Receptor Trafficking
PLCe is essential for PACAP-stimulated secretion from chromaffin cells
Short Term CDK4/6 Inhibition Radiosensitizes Estrogen Receptor Positive Breast Cancers
Varying Levels of Pavlovian Conditioning Affect Cocaine Conditioned Reinforcement
Potential Involvement Of Peripheral Opioid Receptors In the Development Of Tolerance To u-Opioid Receptor Agonists
Differential hERG subunit transcription drives changes in IKr during cardiac maturation
Investigation of Golgi-resident β1-adrenergic receptor signaling to cardiac hypertrophy in cardiac myocytes in vitro and in failing hearts in vivo
Understanding the spatiotemporal regulation of neutrophil infiltration in stressed skin in vivo
Investigating the effect of site-specifically conjugated Thrombomodulin to anti-Icam in mouse with acute lung infection
Boosting TCR Signaling with a Kinase Activator
Group B (3-3:30 PM)
cocaine induced reinforcing effects are unaltered by chronic neuropathic pain in rats
Functional characterization of P450 17A1 mutations to probe for selective 17,20 lyase deficiency
Docking-Based Composite Virtual Screen for the Prediction of Putative Viral Targets of SARS-CoV-2 through Drug Repurposing
Investigating the involvement of VAMPs in GPCR exocytosis
Scn1b deletion results in sinoatrial node dysfunction, atrial remodeling, and increased susceptibility to atrial fibrillation in neonates
Effects of Cocaine on Locomotor Sensitization and Glutamatergic Plasticity in the Nucleus Accumbens
Trafficking and signaling of the mu-opioid receptor variant N40D
The role of mu-opioid phosphorylation in the development of tolerance to affective pain circuitry
Characterization of mitochondria in ES-Derived ß Cells
The use of proximity dependent labeling (PDL) to identify novel G(alpha)i-coupled effectors
Endocytic trafficking and signaling of proton-sensing receptor GPR65
Effects of High Fat Diet-Induced Obesity on Insulin Resistance in the Nucleus Accumbens
Virus-Derived Activators of T Cell Signaling Pathways
SYNERGISTIC ACTIVATION OF PLC-DEPENDENT DIACYGLYCEROL (DAG) PRODUCTION BY MU-OPIOID RECPTORS AND Gq COUPLED RECEPTOR SIGNALING
Wednesday, October 21