Browsing by Author "Sumien, Nathalie"
Now showing 1 - 20 of 70
- Results Per Page
- Sort Options
Item Acute sex difference in response to repeated mild traumatic brain injury in mice(2023) Kuo, Aaron; Schreihofer, Derek; Sumien, Nathalie; Vann, Philip; Ahmed, AffanAcute sex difference in response to repeated mild traumatic brain injury in mice Aaron Kuo, Philip Vann, Nathalie Sumien, Ahmed Affan, Derek Schreihofer Background: Repetitive mild traumatic brain injury (rmTBI), such as that occurring in contact sports, is associated with the development of neurodegenerative diseases of aging. Severe TBI and repetitive concussions are associated with chronic traumatic encephalopathy (CTE), Alzheimer’s disease (AD), and Parkinson’s disease (PD), among others. However, less severe injuries may also lead to delayed neurological disfunction if repeated often and without sufficient rest time between injuries. Previously, we found that the progression of behavioral deficits in males and female mice differed from 5 to 15 weeks after 25 rmTBI. Both sexes showed motor deficits at 5 weeks, but only males showed affective and cognitive deficits at 15 weeks. Purpose: This study tested the hypothesis that rmTBI neurological deficits in male mice will appear earlier after rmTBI than in female mice. Methods: C57BL/6 male and female mice (8 wk old) were assigned to sham and rmTBI groups (n=20/group). Lightly anesthetized mice received 7 mild head injuries, once a day (M-F) using a weight drop model (75 g from 1 meter) that included a free fall with rotational injury. Five minutes after the final injury, mice were tested on a balance beam. Additional behavioral assessments began the following day. Results: No sex differences in balance beam performance were observed 5 minutes after the final injury. There were no significant effects of rmTBI on vestibular motor function assessed with a rotarod; cognition assessed with the Morris water maze; or affective behavior assessed with the elevated plus maze. However, in the open field test there was a significant increase in total distance traveled in rmTBI mice (F1,35 = 6.47, P=0.016). Post-hoc analysis revealed that this effect was only significant in male mice (Fisher LSD, P<0.05), supporting the hypothesis that males exhibit earlier deficits than females. Conclusion: At extended time points following rmTBI, both male and female mice develop motor deficits. However, up to 15 weeks after injury, only male mice experience cognitive and affective deficits. The current study reveals that male mice also display hyperactivity in the week after rmTBI that is not observed in female mice. Thus, sex differences in response to rmTBI are apparent both in the acute and chronic phase of injury and suggest that interventions to reduce brain injury may require different timing for males and females. Ongoing studies are examining potential differences in biochemical and histological responses in the brains of male and female mice. AUP: 2021-0035Item Administration of 5-methoxyindole-2-carboxylic acid that potentially targets mitochondrial dihydrolipoamide dehydrogenase confers cerebral preconditioning against ischemic stroke injury(2018-03-14) Li, Rongrong; Li, Wenjun; Ren, Ming; Thangthaeng, Nopporn; Sumien, Nathalie; Liu, Ran; Yang, Shaohua; Simpkins, James; Forster, Michael J.; Yan, Liang-Jun; Wu, JinziPurpose: The purpose of this study was to investigate a possible role of mitochondrial dihydrolipoamide dehydrogenase (DLDH) as a chemical preconditioning target for neuroprotection against ischemic injury. Methods: We used 5-methoxyindole-2-carboxylic acid (MICA), a reportedly reversible DLDH inhibitor, as the preconditioning agent and administered MICA to rats mainly via dietary intake. Upon completion of 4 week's MICA treatment, rats underwent 1 h transient ischemia and 24 h reperfusion followed by tissue collection. Results: Our results show that MICA protected the brain against ischemic stroke injury as the infarction volume of the brain from the MICA-treated group was significantly smaller than that from the control group. Data were then collected without or with stroke surgery following MICA feeding. It was found that in the absence of stroke following MICA feeding, DLDH activity was lower in the MICA treated group than in the control group, and this decreased activity could be partly due to DLDH protein sulfenation. Moreover, DLDH inhibition by MICA was also found to upregulate the expression of NAD(P)H-ubiquinone oxidoreductase 1(NQO1) via the Nrf2 signaling pathway. In the presence of stroke following MICA feeding, decreased DLDH activity and increased Nrf2 signaling were also observed along with increased NQO1 activity, decreased oxidative stress, decreased cell death, and increased mitochondrial ATP output. We also found that MICA had a delayed preconditioning effect four weeks post MICA treatment. Conclusion: Our study indicates that administration of MICA confers chemical preconditioning and neuroprotection against ischemic stroke injury.Item AMP-Activated Protein Kinase (AMPK) signaling regulates the age-related decline of hippocampal neurogenesis(2018-05) Wang, Brian S.; Jin, Kunlin; Hodge, Lisa M.; Singh, Meharvan; Sumien, Nathalie; Yang, ShaohuaAging is the progressive decline of physiological function and increased vulnerability to disease and death. By the year 2050, 2 billion people will be over the age of 60. Accompanying this, the incidence of age-associated neurological diseases is expected to rise. Thus, there is an urgent need to find therapies to promote healthy brain aging. The finding that neurogenesis continues into adulthood allows us to target endogenous neurogenesis as a potential therapeutic. However, the number of stem cells can decrease by about 80% in the aged brain and is a main cause for the decrease in brain function. The reasons for the age-related decline in neurogenesis can be due to intrinsic factors such as cell metabolism, which have been studied but its role in neurogenesis remains largely unexplored. Interestingly, neural stem cells (NSCs) possess metabolically different characteristics from their differentiated progeny, suggesting the need for a shift in cellular metabolism to accommodate the requirements for neurogenesis. In the process of the metabolic shift, the AMP-activated protein kinase (AMPK) plays a pivotal role for controlling stem cell proliferation and differentiation as a cell's master metabolic regulator. Additionally, AMPK has been reported to control the functions of signaling pathways that regulate the aging process, which suggests its potential involvement in the age-related decline of neurogenesis. Therefore, we hypothesize that inhibition of AMPK signaling activation (phosphorylation) in the old brain will cause a concomitant increase in hippocampal neurogenesis. Our specific aim is to establish whether AMPK signaling plays a critical role in the age-related decline of hippocampal neurogenesis. Our objectives for this aim are to (i) determine the expression pattern of AMPK in the subgranular and subventricular zones of young-adult and old mice using immunohistochemistry and Western blotting; and (ii) examine the impact of loss or gain of AMPK activation on hippocampal neurogenesis in young-adult and old mice using pharmacological agents Compound C (AMPK inhibitor) and 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR, AMPK activator). Our results show that (i) AMPK subunit isoforms are differentially expressed in the neurogenic regions – most are localized to the cytoplasm in the subgranular zone (SGZ) with the exception of α2 and β1, while most isoforms are found in the nucleus in the subventricular zone (SVZ) except α1; (ii) AMPK signaling activation was significantly increased in the SGZ and SVZ; and (iii) short-term but not long-term pharmacological inhibition of AMPK signaling could partially rescue hippocampal neurogenesis in the old brain. Taken together, these results indicate that AMPK is a critical mediator in the regulation of downstream processes for the age-related decline in hippocampal neurogenesis.Item ApoE Genotype-Dependent Response to Antioxidant and Exercise Interventions on Brain Function(MDPI, 2020-06-25) Chaudhari, Kiran; Wong, Jessica M.; Vann, Philip H.; Como, Tori; O'Bryant, Sid E.; Sumien, NathalieThis study determined whether antioxidant supplementation is a viable complement to exercise regimens in improving cognitive and motor performance in a mouse model of Alzheimer's disease risk. Starting at 12 months of age, separate groups of male and female mice expressing human Apolipoprotein E3 (GFAP-ApoE3) or E4 (GFAP-ApoE4) were fed either a control diet or a diet supplemented with vitamins E and C. The mice were further separated into a sedentary group or a group that followed a daily exercise regimen. After 8 weeks on the treatments, the mice were administered a battery of functional tests including tests to measure reflex and motor, cognitive, and affective function while remaining on their treatment. Subsequently, plasma inflammatory markers and catalase activity in brain regions were measured. Overall, the GFAP-ApoE4 mice exhibited poorer motor function and spatial learning and memory. The treatments improved balance, learning, and cognitive flexibility in the GFAP-ApoE3 mice and overall the GFAP-ApoE4 mice were not responsive. The addition of antioxidants to supplement a training regimen only provided further benefits to the active avoidance task, and there was no antagonistic interaction between the two interventions. These outcomes are indicative that there is a window of opportunity for treatment and that genotype plays an important role in response to interventions.Item Assessment of Sex Differences Following Repeated Mild Head Injuries(2022) Duggal, Aakaash; Vann, Philip; Metzger, Daniel; Ahmed, Affan; Sumien, Nathalie; Schreihofer, DerekBackground: Traumatic brain injury (TBI) is a major cause of disability, morbidity, and mortality in the U.S. Although there is a growing understanding of the effects of moderate and severe TBI, less is understood about the effects of repetitive mild TBI (rmTBI). Nevertheless, some studies show that long term participants in contact sports have an increased risk for neurodegenerative disease. In addition, there is limited information about sex differences in TBI, despite some studies suggesting females participating in contact sports experience more head injuries than males. With an increasing number of females participating in contact sports, it's important to explore the effects of rmTBI in females. Purpose: This study will test the hypothesis that rmTBI will lead to more severe neurological deficits in female mice than in male mice. Methods: C57BL/6 female mice were assigned to sham and rmTBI groups (n=30/group). Lightly anesthetized mice received 25 mild head injuries, once a day (M-F) over 5 weeks using a weight drop model that included a free fall with rotational injury. Acute effects of injury were assessed by righting reflex and balance beam tests weekly. Chronic effects were tested with rotarod, Morris water maze (MWM), elevated plus maze (EPM), and T-maze beginning 5 or 25 weeks after the last injury. Effects in female mice will be compared to previously collected data in male mice. Inflammation and white matter injury will be assessed with western blotting and immunohistochemistry, respectively. Results: Acutely, rmTBI female mice performed worse than sham injured mice on the balance beam (F (1,28) =4.309, P=0.0472) whereas there was no difference in males. Five weeks after injury, both male and female mice in the rmTBI group performed significantly (T-test P< 0.01) worse on the Rotarod. Neither males nor females displayed deficits in cognition on the T-Maze or learning phase of the MWM, although males had a significant impairment on MWM memory (Probe T-test P< 0.05). Neither sex showed deficits in the EPM. Fifteen weeks after injury, male mice displayed significant deficits in learning in the MWM (T-test P< 0.05) and EPM (T-test P< 0.05). Male mice in the rmTBI group also showed increased astrogliosis and Tau phosphorylation in the cerebral cortex compared to sham injured mice. Additional assessments of white matter injury are planned, but assessment of female mice 15 weeks after injury is incomplete at this time. Conclusion: Acutely, female mice showed balance deficits that were not apparent in males. Five weeks after injury, both sexes continued to show motor deficits on the rotarod, but only males had mild deficits in cognition. Ongoing studies will assess whether these differences persist or new differences between males and females appear chronically. AUP: 2021-0035Item Assessment of Sex Differences Following Repeated Mild Head Injuries(2022-05) Duggal, Aakaash; Schreihofer, Derek A.; Sumien, Nathalie; Luedtke, Robert R.There is limited information about sex differences in mRHI, despite some studies suggesting females participating in contact sports experience more head injuries than males. This study will test the hypothesis that mRHI will lead to more severe neurological deficits in female mice than in male mice. C57BL/6 female mice were assigned to sham and mRHI groups (n=30/group). Lightly anesthetized mice received 25 mild head injuries, once a day (M-F) over 5 weeks using a weight drop model that included a free fall with rotational injury. Acutely, mRHI female mice performed worse than sham injured mice on the balance beam (F (1,28) =4.309, P=0.0472) whereas there was no difference in males. 5 weeks and 15 weeks after injury mice underwent a 3-week series of behavioral tests. Both male and female mice in the mRHI groups performed significantly (T-test P< 0.01) worse on the Rotarod than uninjured controls. Only males in MWM showed significant impairment on memory for 5-week and significant impairment on spatial learning and memory for 15-week (Probe T-test P< 0.05). Only 15-week male mice showed deficits in elevated plus maze (EPM) (T-test P< 0.05). Acutely, female mice showed balance deficits that were not apparent in males. Fifteen weeks after mRHI, males no longer displayed deficits in the rotarod, but female mice continued to have a decrease in performance compared to controls (T-test, P<0.05). Unlike the males, female mice did not display any significant deficits in the MWM and EPM.Item Association of Pain Sensitivity with Outcome Measures for Quality of Life, Functional Ability and Current Pain Intensity in Chronic Low Back Pain(2021-05) Doud, Ronnie L.; Sumien, Nathalie; Licciardone, John C.; Kearns, Cathleen; Phillips, Nicole R.Pain sensitivity, as measured by the self-reported Pain Sensitivity Questionnaire (PSQ), was investigated using data from the PRECISION Pain Research Registry. Outcome measures for quality of life, functional ability, and current pain intensity were found to be significantly associated with PSQ Total in participants reporting chronic low back pain, even when controlling for age, sex, race, ethnicity, smoking status, and body mass index. Higher reported pain sensitivity correlated with reported higher pain intensity, lower quality of life, and increased physical disability.Item Astrocyte HIV-1 Tat Differentially Modulates Behavior and Brain MMP/TIMP Balance During Short and Prolonged Induction in Transgenic Mice(Frontiers Media S.A., 2020-12-15) Joshi, Chaitanya R.; Stacy, Satomi; Sumien, Nathalie; Ghorpade, Anuja; Borgmann, KathleenDespite effective antiretroviral therapy (ART), mild forms of HIV-associated neurocognitive disorders (HAND) continue to afflict approximately half of all people living with HIV (PLWH). As PLWH age, HIV-associated inflammation perturbs the balance between brain matrix metalloproteinases (MMPs) and their tissue inhibitors of metalloproteinases (TIMPs), likely contributing to neuropathogenesis. The MMP/TIMP balance is associated with cognition, learning, and memory, with TIMPs eliciting neuroprotective effects. Dysregulation of the MMP/TIMP balance was evident in the brains of PLWH where levels of TIMP-1, the inducible family member, were significantly lower than non-infected controls, and MMPs were elevated. Here, we evaluated the MMP/TIMP levels in the doxycycline (DOX)-induced glial fibrillary acidic protein promoter-driven HIV-1 transactivator of transcription (Tat) transgenic mouse model. The HIV-1 protein Tat is constitutively expressed by most infected cells, even during ART suppression of viral replication. Many studies have demonstrated indirect and direct mechanisms of short-term Tat-associated neurodegeneration, including gliosis, blood-brain barrier disruption, elevated inflammatory mediators and neurotoxicity. However, the effects of acute vs. prolonged exposure on Tat-induced dysregulation remain to be seen. This is especially relevant for TIMP-1 as expression was previously shown to be differentially regulated in human astrocytes during acute vs. chronic inflammation. In this context, acute Tat expression was induced with DOX intraperitoneal injections over 3 weeks, while DOX-containing diet was used to achieve long-term Tat expression over 6 months. First, a series of behavior tests evaluating arousal, ambulation, anxiety, and cognition was performed to examine impairments analogous to those observed in HAND. Next, gene expression of components of the MMP/TIMP axis and known HAND-relevant inflammatory mediators were assessed. Altered anxiety-like, motor and/or cognitive behaviors were observed in Tat-induced (iTat) mice. Gene expression of MMPs and TIMPs was altered depending on the duration of Tat expression, which was independent of the HIV-associated neuroinflammation typically implicated in MMP/TIMP regulation. Collectively, we infer that HIV-1 Tat-mediated dysregulation of MMP/TIMP axis and behavioral changes are dependent on duration of exposure. Further, prolonged Tat expression demonstrates a phenotype comparable to asymptomatic to mild HAND manifestation in patients.Item Astrocyte TIMP-1: Regulation and Gene Delivery in HAND(2018-12) Joshi, Chaitanya R.; Ghorpade, Anuja; Clark, Abbot F.; He, Johnny J.; Sumien, Nathalie; Rickards, Caroline A.Despite antiretroviral therapy, HIV-associated neurocognitive disorders (HAND) persist in 30-70% of patients. During HAND, elevated matrix metalloproteinases (MMPs) in the brain exacerbate the disease by blood-brain barrier breakdown, neuroinflammation and direct neurotoxicity. Tissue inhibitors of metalloproteinases (TIMPs) counter MMP activity. In the brain, TIMP-1 is primarily produced by astrocytes in response to injury or inflammation. However, TIMP-1 is downregulated during chronic inflammation in astrocytes and in HIV encephalitis brain tissues. We propose that restoring astrocyte TIMP-1 levels could mitigate neurodegeneration due to its MMP-inhibitory and -independent neuroprotective functions. HIV-1 non-productively infects astrocytes, which express viral proteins such as transactivator of transcription (Tat). As Tat mimics aspects of HAND by direct and indirect mechanisms, glial fibrillary acidic protein (GFAP) promoter-restricted Tat expressing (GT-Tg) mice were used to model HAND in our studies. Prolonged astrocyte Tat expression in GT-Tg mice resulted in HAND-relevant behavioral impairments characterized by higher anxiety, lower ambulation, impaired spatial learning, and memory. Importantly, behavioral deficits were accompanied by altered brain MMP/TIMP balance. Our data from GT-Tg mouse model confirmed neurocognitive decline and TIMP-1 dysregulation in the context of HAND. As TIMP-1 was downregulated with prolonged Tat expression in mice, we focused on replenishing TIMP-1 via gene delivery to the brain using cationic polymers. Polyethylenimine (PEI) is a highly efficient polymer for transfecting mammalian cells, however, high cytotoxicity restricts its use. Hence, PEI was modified using arginine (A) and stabilized with polyethylene glycol (P) to produce multiple AnPn analogues. AnPn analogues were biocompatible and successfully delivered reporter genes to primary neural cells. Select AnPn led to sustained reporter gene expression in human astrocytes and in mouse brains. In order to restrict gene expression to astrocytes, truncated GFAP promoters were used to drive gene expression. Subsequently, GFAP promoters were modified enhancing their activity and increasing gene expression. Lastly, successful polymer-mediated GFAP promoter-driven TIMP-1 gene delivery was demonstrated in human astrocytes. Overall, these findings enhance our understanding HIV-1 Tat-mediated TIMP-1 regulation, provide a novel therapeutic TIMP-1 gene delivery system, and pave the way for future investigations geared towards preclinical translation of TIMP-1-based HAND therapy.Item Carisoprodol's Pharmacological Properties at GABAA Receptors, In-vitro and In-silico Studies(2021-05) Claudio, Maria del Carmen; Sumien, Nathalie; Huang, Ren-Qi; Gonzales, Eric B.; Dillon, Glenn H.; Mathew, Porunelloor A.Carisoprodol (CSP) is a centrally-acting prescription muscle relaxant that can directly activate, allosterically modulate and inhibit GABAA receptors. The GABAA receptor is a pentameric chloride ion channel in the cys-loop receptor family. The mechanism of GABAA's inhibitory role in the central nervous system lies in the resulting hyperpolarized state of the cell following chloride ion influx upon ligand binding. GABAA receptors are the target of many different clinically prescribed compounds because of the role they play in regulating the central nervous system. We used pharmacological and computational approaches to investigate the underlying mechanism mediating carisoprodols effects at GABAA receptors, with the ultimate goal of generating a new subunit selective compound related to the structure of carisoprodol and gaining a more thorough understanding of the molecular interaction governing carisoprodol's pharmacoglogical effects. Our evaluation of novel compounds related to the structure of carisoprodol did not yield promising leads, though the potential still remains for development of a novel carisoprodol-related compound with a unique selectivity profile. Probe for a binding site mediating carisoprodols postive modulatory effects and evaluation of additional novel compounds was eventually hindered by time. Our investigaiton into carisoprodol's direct gating effects involved a previously reported single amino acid residue, L415, located at the top of the fourth transmembrane domain (TM4) in the ɑ1 subunit of the GABAA receptor that is critical to carisoprodol's direct gating. Whether the residue is involved in a carisoprodol binding site remained unsolved. In studies probing for a binding site for carisprodol's direct activation of GABAA receptors, promising computaitonal docking data was not able to be validated with elecrophysiology and site-directed mutatgenesis studies, indicating that the residues revealed in docking studies do not form a binding pocket for carisprodol's direct activation effect. Our site directed mutagenesis, electrophysiology and molecular dynamic simulation studies to investigate carisoprodol's inhibitory effects at GABAA receptors revealed a binding site at the Cl- channel pore, in a mechanism similar to picrotoxin, providing a mechanism of action for carisoprodol's inhibitory effects at GABAA receptors.Item Catwalk analysis: a novel approach to profiling age differences in gait(2016-03-23) Wong, Jessica; Vann, Phillip; Forster, Michael; Sumien, Nathalie; Mock, J.The Catwalk is a validated video-based gait analysis tool for quantitative analysis of both static and dynamic differences in rodent gait and weight-bearing. The Catwalk has been used to analyze disease states such as stroke, sciatic nerve crush and osteoarthritis, however age-related changes in rodent gait are not well characterized. Motor impairments have been associated with dysregulated cellular redox state, namely levels of reduced to oxidized glutathione. Glutamate-cysteine ligase modifier (gclm) is a key enzyme sub-unit in the production of glutathione (GSH), and knocking it out reduces GSH levels by 85%. The gclm -/- mice are a potential model of accelerated aging and should develop impairments earlier than wild-type mice. Our hypothesis was that gait measures would decrease with advanced age and that impairments would occur sooner in gclm -/- mice. Wild-type (wt) and gclm-/- male and female mice were tested at 4, 10 or 17 months of age (n = 8-11/group). All testing was done in pitch black and a camera below the illuminated transparent platform captured each paw print as animals walked across the platform. Paw prints were automatically labeled according to left/right or front/hind then manually checked. A criterion for a good run was set as less than 60% speed variation within the run and less than 10% speed variation between runs. Two to five runs per animal were used for two-way analyses of variance of the dependent measures collected using Genotype and Age as in between factors. The dependent measures were gait speed (SP), front and hind base of support (BoSf, BoSh), front and hind stride length (SLf, SLh), front and hind stride speed (SSf, SSh), front and hind step cycle (SCf, SCh), and front and hind duty cycle (DCf, DCh). Gait speed decreased with age in both genotypes. BoS decreased in front legs and increased in hind legs in both genotypes. Stride length was decreased with age, and more prominently in the gclm-/-, while stride speed decreased with age and was higher in gclm-/-. Step cycles increased with age in the wt but not in the gclm-/-. Duty cycles increased with age, especially in the gclm-/-. These preliminary data suggest that age leads to measurable changes in mouse gait and that GSH dysregulation had only minor effects on gait. In conclusion, Catwalk analysis is sufficiently sensitive to measure subtle age-related changes in gait across several age-ranges, and can be added to the current battery of behavioral tests.Item Chronic testosterone deprivation sensitizes the middle-aged rat brain to damaging effects of testosterone replacement(2020) Vann, Philip; Wong, Jessica; Sumien, Nathalie; Cunningham, Rebecca; Metzger, Daniel; Schreihofer, Derek; Oppong-Gyebi, Anthony; Contreras Garza, Jo; Kasanga, Ella; Smith, CharityHypothesis: We hypothesized that a delay in testosterone replacement therapy (TRT) following castration in middle-aged male rats would result in increased oxidative stress and a reduction in the neuroprotective effects of testosterone following stroke. Background: Levels of the hormone testosterone (T) fall in aging men. Recently, the number of men obtaining TRT has increased dramatically. However, other consequences of aging, such as oxidative stress, may result in detrimental effects when combined with TRT, including stroke risk. Methods: Twelve-month old male Fischer 344 rats were divided into 5 groups (n=9-14): 1) gonad Intact sham stroke (SH), 2) Intact stroke (IN), 3) short term castrate + T (ST), 4) long term castrate (LC), and 5) long term castrate + T (LCT). Rats were castrated 2 weeks (ST) or 10 weeks (LT, LCT) prior to T. Middle cerebral artery occlusion (Stroke) done via stereotaxic injection of endothelin 1 (ET1). Three, 7, and 14 days after stroke several behavior tests were done. Rats were humanely euthanized, and blood/brains were collected. Results: Plasma oxidative stress measured by Advanced Oxidative Protein Products (AOPP) was significantly negatively correlated with T levels. Long-term hypogonadism in middle-aged male Fischer 344 rats TRT exacerbated the detrimental behavioral effects of experimental focal cerebral ischemia. Conclusion: Data suggest that TRT after long-term hypogonadism can exacerbate functional recovery after focal cerebral ischemia.Item Cocaine-induced stroke susceptibility: motor and cognitive outcomes(2018-03-14) Taylor, Cynthia; Li, Wenjun; Forster, Michael; Yang, Shaohua; Sumien, Nathalie; Vann, PhilipTitle: Cocaine-induced stroke susceptibility: motor and cognitive outcomes Presenters: Philip Vann, Cynthia Taylor, Wenjun Li, Michael J. Forster, Shaohua Yang, Nathalie Sumien Purpose: Epidemiological findings suggest that the number of young individuals suffering from stroke seems to be increasing, and one of the most common cause for such an increase is the use of illicit drugs. Prior work in our laboratory suggested that life-long cocaine intake impaired cognitive function and that short-term intake induces brain changes conferring vulnerability. In this study, we tested the hypothesis that repeated cocaine use will induce brain vulnerability to ischemic stroke. Methods: Fifty seven young male Sprague-Dawley rats (3 months) were injected i.p. with cocaine (10mg/kg) or saline (3 times/wk) for 4 weeks. From each treatment group, half of the rats received an ischemic stroke (transient Middle Cerebral Artery Occlusion) and the other half a sham surgery. After a one month recovery period, the rats were subjected to a behavioral battery of tests measuring balance, motor function, spatial learning and long term memory (locomotor activity, bridge walking, rotorod, and Morris water maze). Once behavioral testing was finalized the rats were euthanized and brain regions were collected for further biochemical analyses. Data were analyzed using 2- or 3-way ANOVAs followed by pairwise comparisons. Results: The stroke surgery resulted in decreased body weights and increased overall activity (total distance travelled and horizontal activity). Maximum performance on the rotorod was lower for the stroked rats than for the shams, and treatment with cocaine did not affect the outcome. However, during training the cocaine-treated rats had higher latencies than the controls. On the bridge walking test, the stroke surgery did not seem to affect performance, however the cocaine-treated stroke rats performed the worst. The stroked rats took longer path length and latencies to reach the platform, and cocaine seem to exacerbate the impairment, more specifically at the end of training and during retention. Conclusions: While preliminary, these results suggest that cocaine-treated rats were more vulnerable to stroke than the saline-treated ones but exhibiting exacerbated impairments on balance and spatial learning and memory. Studies to identify the underlying mechanisms of this vulnerability are underway. IACUC 2016-0022 Intramural grant UNTHSC RI10014Item Computational Pharmacology Towards RGS12 Inhibitors(2021-05) Dadeboe, Ian R.; Siderovski, David; Sumien, Nathalie; Schreihofer, Derek A.Background/Introduction: "Regulator of G protein Signaling" proteins, also referred to as RGS proteins, inhibit signal transduction by accelerating the hydrolysis of guanosine triphophate (GTP) to guanosine diphosphate (GDP) on the G-alpha subunit of G protein-coupled receptors (GPCRs). Sequence variations of RGS12, which is a member of the RGS protein superfamily, have been observed in some genetic profiles of people with attention-deficit hyperactivity disorder (ADHD), bipolar disorder, and schizophrenia. Hence the purpose of this study was to perform an in silico exploration of the structure/function correlation of small molecule inhibitors of the RGS12 RGS-box domain predicted to inhibit RGS12. Using these small molecule inhibitors in the mouse or rat brain would provide information on whether inhibition of RGS12 can lead to brain changes and/or behavioral changes similar to the human mental health disorders of ADHD, bipolar disorder, or schizophrenia. Method: In silico visualization and exploration of predicted small molecule inhibitors of the RGS box of RGS proteins were evaluated using the Schrodinger software suite (version 2020-3). Ninety-six predicted inhibitors underwent ligand preparation (e.g., tautomer resolution) and Glide docking within structural models of RGS4, RGS12 and RGS14. The resulting ligand and receptor interactions were quantified using Schrodinger Maestro (2020-3). In parallel, all 96 compounds were sent to BellBrook Labs for in vitro testing of GAP inhibitory activity. Results: Three compounds Z##6112, Z##0043, and Z##6197 with shared chemical features, i.e., thioether linkages, and linked sulfur and nitrogen heteroatoms, were observed to inhibit RGS12's GAP activity at least three standard deviations away from the average assay signal. Two unique features of the Z##6197 compound, a carboxylic acid group and a halogenated, ether-coupled phenolic ring, were found to inhibit in silico Glide docking or be docked in varied poses with differing chemical-bond engagements within the RGS-box receptor grids, respectively. Conclusions: Discrepancies between the in silico Glide docking and in vitro biochemical results bring into question the validity of the Glide algorithm to correctly predict the geometry and chemical-bonding character of RGS-box / small molecule inhibitor engagement. Further testing of the three identified compounds in other in vitro assays and in establishing three-dimensional structural models of their RGS-box engagement will assist in resolving these discrepancies and reveal both shared and unique determinants of RGS12 inhibition necessary for future in vivo and clinical applications.Item CURCUMIN SUPPLEMENTATION IMPROVES CERTAIN ASPECTS OF COGNITION AND ALLEVIATES INFLAMMATION, INDEPENDENT OF ADIPOSITY(2014-03) Sarker, Marjana R.; Franks, Susan F.; Sumien, Nathalie; Filipetto, Frank; Forster, MichaelThe study was designed to investigate the effects of curcumin on blood based biomarkers and mental health in a chronic mid-life obese state. 3 groups were studied, mice on a regular diet, on a calorically restricted diet and on a regular diet supplemented with curcumin. These mice were kept on their respective diets for 12 weeks. Two behavioral studies to investigate mental health in particular memory, were utilized. Our results conclude that curcumin dietary treatment positively affects specific domains of mental health possibly by the lowering of inflammation but this effect is independent of fat loss. Purpose (a): Midlife obesity has been recently associated with cognitive impairment that may be attributed to chronic, obesity-related inflammation and oxidative stress. Commonly used laboratory mice fed ad libitum are an analogue of weight gain in middle aged humans, since accumulating fat is more often the result of food intake exceeding energy expenditure and not solely because of a high fat diet. The current study addressed the hypothesis that curcumin supplementation, by attenuating obesity and adiposity -related inflammation, would improve cognition in a midlife obesity animal model. Methods (b): C57BL/6J male mice were maintained under ad libitum (AL) feeding until they reached peak weight at 15 months of age, as a model of inactivity-related weight gain. The mice were subsequently assigned in groups of 19 to: (i) remain on AL, (ii) receive 30% caloric restriction (CR) or (iii) receive curcumin in their AL diet (1000 mg/kg diet, CURC) for 12 weeks. Mice underwent tail bleeds for the inflammatory markers, interleukin 6 (IL-6) and C-reactive protein (CRP) and, after 8 weeks of dietary treatment, spatial cognitive function was tested using a Morris water maze, followed by testing for cognitive flexibility using a discriminated avoidance, serial reversal task. Visceral (VAT) and subcutaneous (SAT) adipose tissue was collected after 12 weeks of the treatments. Results (c): Mice maintained on CR weighed significantly less than mice on the CURC and AL diets by the third week of treatment. Food intake of the CURC group was significantly higher than AL. Mice on CR and CURC diets took fewer trials than AL to reach criterion during the second reversal session of discriminated avoidance, suggesting that both conditions improved cognitive flexibility. However, there were no significant differences between the groups in their spatial cognitive performance. Mice maintained on CR had significantly less VAT and SAT compared to mice on CURC and AL. Curcumin supplementation did not significantly impact IL-6 levels but it did reduce CRP relative to AL mice. Conclusions (d): Results suggest that in a midlife obesity animal model, curcumin supplementation has positive effects on frontal cortical functions that may be linked to an anti-inflammatory action. It appears that these effects may be independent of adiposity. Curcumin intake may also facilitate energy expenditure or diminish efficiency, as suggested by the increase in energy intake in the absence of weight loss in the CURC mice. Future studies will determine the metabolic and cognitive consequences of higher curcumin doses.Item Development of a mouse model to study the long-term effects of chemotherapy on brain function(2023) Trinh, Oanh; Vann, Philip; Davis, Delaney; Luedtke, Robert R.; Basha, Riyaz; Singh, Meharvan; Sumien, NathaliePurpose: While remaining an effective life-saving intervention for cancer patients, chemotherapy has been associated with many neurotoxic side effects, including chemotherapy-related cognitive impairments (CRCI). Chemotherapy exposure leads to a decline in learning, memory, processing speed, attention, and executive functions, which may persist for more than 20 years post-treatment, impairing the quality of daily lives of survivors. Childhood cancer survivors are particularly vulnerable to chemotherapy and have been impacted in their educational achievements, employment, social relationships, and even life expectancy. Most common childhood cancers are often treated with the folate-inhibitor methotrexate (MTX). Our study aimed at establishing a tumor-free mouse model of MTX-induced brain impairments. We hypothesized that early exposure to MTX would induce impairment in cognition, as well as motor and affective functions. Methods: Male and female C57BL6/J postnatal day 15 pups received intraperitoneal injections of saline or MTX (2 mg/kg) once a day for 3 days. Pups were weaned on PND21, and subsets were behaviorally characterized at 1 or 7 months after MTX exposure (n=6-8 for 1.5 months old, and n=11-13 for 8 months old) for motor, affective and cognitive functions using a comprehensive behavioral test battery. Results: At 1.5 months, coordination and motor learning was significantly impaired in males and improved in females. All other measures did not reveal any other significant effects, however trends of impaired motor and cognitive functions could be discerned. At 8 months, there were no effects of MTX on motor, affective and some cognitive functions. However, MTX exposure led to an impairment on spatial learning and memory and increased swimming speed. Conclusions: Studies at 1.5 months will need to be repeated to increase power and ascertain conclusions on brain functions. Early exposure to MTX treatment led to long-term impairments in both male and female mice and could be used as a model to test interventions to limit CRCI.Item Dietary Curcumin And Caloric Restriction As Interventions For The Reversal Of Age Associated Functional Decline(2015-12-01) Sarker, Marjana R.; Forster, Michael J.; Franks, Susan; Sumien, NathalieAugmentation and exacerbation of oxidative stress and low-grade chronic systemic inflammation during mid-life has been proposed as modifiable causative factors for neurobehavioral decline reported with normal aging. Physiologically, the imbalance of pro-oxidants and endogenous antioxidants leads to an increase in tissue- damaging oxidative stress. Aging has also been associated with chronic systemic inflammation that can damage healthy tissues and diminish cognitive and motor capacity. The overall hypothesis of this project is that caloric restriction and dietary curcumin, via their strong anti-oxidant and anti-inflammatory properties; can delay the onset or ameliorate cognitive and motor decline in middle aged and aged mice respectively. Study 1: Fifteen month-old male C57BL/6 mice were tested as a model of sedentary mid-life obesity for the pilot study. They underwent dietary treatment for 12 weeks and were subjected to cognitive tests at the 8th week of treatment. Dietary treatments included regular chow fed ad libitum (AL), curcumin (1g/kg of diet) fed ad libitum (CURAL) and 30% to weight stable caloric restriction (CR). Mice were tested for spatial learning and cognitive flexibility testing. Blood was collected to measure inflammation and oxidative stress. Results from the pilot study indicated a significant weight loss and reduced adiposity in the CR group; whereas CURAL mice maintained stable weight throughout the treatment, consumed more food than the AL mice, and did not show a reduction of adipose tissue. However, both the CR and CURAL groups took fewer trials than AL to reach criterion during the reversal sessions of the active avoidance task, suggesting an improvement in cognitive flexibility. The AL mice had higher levels of CRP compared to CURAL and CR, and reduced glutathione as well as the GSH/GSSG ratio were increased during curcumin intake, suggesting a reducing shift in the redox state. Study 2: In the subsequent study, 15 and 20 month old female and male C57BL/6 mice were used as a normal aging model to study functional decline. This study included all of the dietary interventions from the pilot study and an additional combination diet of CR and curcumin (CURCR). Curcumin was added to the diet at 7g/kg of diet with mice under CURCR receiving 7.2g/kg of diet, adjusted to take difference in food intake into account. The mice underwent dietary treatments for 4 months, and cognitive and motor behavior tests were conducted at 8 weeks of treatment. Mice were tested on multiple tasks that are sensitive to age associated cognitive and motor dysfunction. Results from the second study indicated females to be more active than males. Mice under CR and CURCR performed better in the motor tests compared to their age matched controls, which included coordinated running, wire suspension and bridge walking. Cognitive flexibility was significantly better for middle-aged males under CR and CURAL compared to AL but not under CURCR, suggesting an antagonistic interaction. On the other hand, middle aged and aged female experimental groups did significantly better than AL. No interaction of CR and CUR was observed in aged males, with CURAL and CR yielding comparable benefits. None of the treatments had a significant effect on hippocampus- dependent rate of learning in middle age or the aged; however middle aged males under the CURCR intervention had poorer probe performance compared to their age matched controls. Data from both projects suggest that independent of weight loss; dietary curcumin and CR have positive effects on fronto-cortical functions in late middle age and senescence that could be linked to anti-inflammatory or antioxidant actions. These effects were similar across different behavioral tasks and were non-additive or antagonistic in a sex dependent manner, suggesting that they could involve the same or similar mechanisms including an influence of sex hormones. Therefore, curcumin intake may mimic the neurobehavioral outcomes of CR that could be age dependent, but the mechanism of action underlying the outcomes of the CR and curcumin combination treatments need to be further examined.Item Does the use of indocyanine green fluorescent dye (ICG) reduce the false negative rates in sentinel lymph node (SLN) biopsy for melanoma cases?(2022-05) Kwizera, Alain; Sumien, Nathalie; Mathew, Stephen O.; Martits-Chalangari, KatalinWith MSLT 1& 2, sunbelt melanoma trials showing the importance and prognostic significance of sentinel node biopsies this study set out to reduce the false negative rates in SLNB using fluorescent dye ICG in increasing the accuracy of confirming sentinel nodes. We injected 2.5 mg of ICG intradermally near the primary melanoma sites and followed NCCN guidelines to plan the sentinel node biopsy site. The Near infrared imaging (NIF) cameras were then used to visually confirm the radiotracer mapped nodes. This study had a total of 60 patients and 26 were eligible for a 2 year follow up to determine the false negative rate. In this study ICG confirmed radiotracer mapped nodes in 100% of the cases and there was no recurrence/ false negative result.Item EFFECT OF ANTIOXIDANTS SUPPLEMENTATION AND MODERATE EXERCISE ON MOTOR FUNCTION IN YOUNG AND OLD MICE(2014-03) Sidhu, Akram; Vann, Philip; Wong, Jessica; Sumien, NathalieThe present study provided an assessment of the effect of exercise and/or vitamins on anxiety, coordinated running and motor function in young and old mice. Our data indicate that the effect of exercise and antioxidant supplementation may vary depending the age of the subject. Furthermore, there seem to be an increase their beneficial outcomes on motor function, when exercise is combined with antioxidant supplementation. Purpose (a): Aging is associated with a decline in psychomotor functioning and ability to learn new motor learning skills. Interventions such as exercise and antioxidants supplementation when investigated independently seem to have a beneficial impact on motor function in both human and animal subjects. A large number of health conscious individuals often combine exercise with vitamin supplementation, anticipating a synergistic effect maximizing their performance. Recent studies have also indicated a potential for an antagonistic action of the antioxidants on the beneficial effects of exercise. To date, it has not been well established what the nature of the interaction between antioxidant supplementation and exercise is in terms of functional outcomes and whether age will influence the outcomes. This study investigated the effects of moderate exercise and antioxidant supplementation on the motor performance of young and old mice. Methods (b): Separate groups of young (4 months), and old (20 months) male C57BL/6J mice were placed under one of the following treatments: Sedentary/control diet (SedCon), Sedentary/antioxidant-rich diet (vitamin E (128 IU/kg/d of body weight) and vitamin C (189 mg/kg/d of body weight); SedEC); Exercise/control diet (ExCon); Exercise/antioxidant-rich diet (ExEC). After 8 weeks of pre-treatment, the mice underwent a series of behavioral tests while remaining on their respective condition (elevated plus maze, spontaneous activity; coordinated running, wire suspension, and bridge walking). Results (c): Our preliminary data suggested that the time spent in the closed arms was increased in all treated mice compared to controls, and that the increase seemed more evident in the young mice. The latency to fall from a rotating rod seemed to be increased in the ExEC young and old mice when compared to all the other groups. The ExCon group had higher latency to fall while the other treatment groups seemed to have lower latencies when compared to SedCon within the young group. In the old group, only the ExEC group had higher latencies that the SedCon group while the others did not seem to differ. Latencies to fall from the bridge were increased in young groups where mice exercised (ExCon and ExEC), while they were decreased in SedEC and ExCon old mice compared to controls. Conclusions (d): Our data indicated that exercise and antioxidant supplementation can affect motor performance of young and old mice. Though preliminary, there seemed to be a differential effect dependent on the age of the mice. Lastly, there seem to be some type of interaction between antioxidant supplementation and exercise that may increase their beneficial outcomes.Item Effect of creatine on nociception in a mouse model of inflammatory pain(2015-05-01) Izurieta Munoz, Haydee S.; Sumien, Nathalie; Gonzales, Eric B.; Gatch, Michael B.The objective of this study was to evaluate creatine as an anti-nociceptive compound in an animal model of thermal and inflammatory pain. Creatine has the structural potential to interact with acid-sensing ion channel 3 (ASIC3), which have been involved in pain sensation modulation. Our hypothesis was that creatine will interact with ASIC3 leading to decreased nociception. Male and female C57BL/6J mice were supplemented with creatine (6.25g/kg diet) and tested for thermal hyperalgesia and inflammatory pain response. The latency to withdraw the tail during the thermal hyperalgesia test was unaffected by sex or diet. For the formalin test, males and females responded differently to the stimulus, and the female mice supplemented with creatine seemed to recover faster than the controls. These preliminary data suggest a potential effect of creatine and sex on inflammation-based nociception and can be used as a stepping stone for the development of ASIC-based therapeutics