Lithium is a drug used to treat mood disorders and also has many side effects, including central nervous system (CNS) complications (such as cognitive dulling), associated with its use. The mechanism of its action still remains unknown. Over the years, many leads have started emerging. It has been shown to inhibit several enzymes in the cell and has been implicated in altering many neurotransmitter systems and signal transduction pathways (serotonin, dopamine and norepinephrine neurotransmissions). Effect of exposure to therapeutic levels of lithium on mature glutamatergic synapses is being studied and several changes in glutamate receptor subtypes have already been reported. Effects of lithium on developing glutamatergic synapses have not been studied. The thesis tries to document and understand the changes brought about by long term lithium treatment on developing glutamatergic synapses in vitro in hippocampal neuronal cultures. In the present work, patch clamp technique was used to monitor the changes in the postsynapse and fluorescence imaging to study the presynaptic changes. The hippocampal neuronal cultures were treated with 1 mM lithium for 6 days during the synaptogenesis stage (DIV 4-10) and termed as chronic Li treatment (CLi). Following CLi treatment the changes occurring in amplitude and rectification property of the AMPA receptor (AMPAR), a subtype of glutamate ionotropic receptor, mediated miniature excitatory postsynaptic currents (mEPSCs) have been reported (Chapter III). Lithium inhibits protein kinase A (PKA), glycogen synthase kinase–3β (GSK-3β) and glutamate reuptake. Effect of inhibiting PKA, GSK-3β and glutamate reuptake was also studied with a view to understand the molecular basis of lithium action on AMPAR mEPSCs (Chapter IV). It was found that chronic lithium treatment (CLi) caused a reduction in the mean amplitude of mEPSCs mediated by AMPARs and also changed the rectification property of these receptors from being more outwardly rectifying to being more inwardly rectifying, an indication probably of increase in contribution of Ca2+-permeable AMPARs to the synaptic events. AMPAR events in chronic lithium treated cultures were more sensitive to both N-acetyl spermine (NASPM) application and di-fluoro-methyl-ornithine (DFMO) treatment, both specific to Ca2+-permeable AMPARs, indicating that there was an increase in the contribution from Ca2+-permeable AMPARs to the synaptic events. PKA inhibition with H-89 treatment (starting from DIV 4 (for 6 days)) reduced the mean amplitude of AMPAR mEPSCs and increased the mean rectification index (RI). GSK-3β inhibition with SB415286 (starting from DIV 4 (for 6 days)) did not alter the mean mEPSC amplitude but reduced the mean RI. Transient (24 hrs) glutamate reuptake inhibition with threo-β-Hydroxy-Aspartic-Acid (THA) at DIV 4 followed by a period of recovery led to smaller amplitudes but no change in RI. The 24 hr glutamate reuptake block on DIV 4 had long term effects. It led to an increase in AMPAR mEPSC frequency while AMPAR mEPSC amplitudes were reduced. The mean RI decrease seen when glutamate reuptake was blocked for 24 hrs on DIV 10, was absent in DIV 4 THA treated neurons. However, when the neuronal cultures were maintained in the presence of PKA and GSK-3β inhibitors, the DIV 4 THA treated neurons showed AMPAR mEPSC characteristics similar to CLi neurons. Thus, it was seen that individual inhibition of PKA, GSK-3β and glutamate reuptake did not lead to changes in AMPAR mEPSCs similar to that seen in lithium treated neurons. The effect of lithium exposure during synapse development on AMPARs could be reproduced closely by co-inhibiting PKA, GSK-3β and glutamate reuptake. Using the styryl dye FM1-43, the changes induced in presynaptic release by a similar chronic lithium treatment was studied (Chapter V). It was found that lithium exposure (1 mM, DIV 4-10) brought down the extent of dye loading, destaining and also slowed down the rate of dye loss in response to high KCl stimulation (the τfast component of destaining was significantly slower). Minimum loading experiments did not reveal any difference in mode of exocytosis (kiss and run/full-collapse) in control and lithium treated cultures. Chlorpromazine treatment (that inhibits clathrin-mediated endocytosis) affected dye loading to a lesser extent in lithium treated cultures as compared to control. Surprisingly, exposure to hyperosmotic solution 10 minutes after dye wash out boosted the extent of dye loading and destaining in lithium treated cultures (a phenomenon not seen in control). This could happen if the FM1-43 is trapped away from the wash solution during the wash period. This would be possible if endocytosis in CLi takes place, differently from control, through a process involving membrane infoldings similar to bulk endocytosis albeit a slower/compromised one. Taken together, the data presented here indicates that lithium treatment during synaptogenesis affects vesicular recycling mostly at the endocytosis and docking/priming steps (mobilization of vesicles for release). Lithium treated cultures also did not show the high KCl associated presynaptic potentiation observed in control which is a significant finding. In conclusion, chronic lithium treatment affected both the presynaptic and postsynaptic compartments of the glutamatergic synapse. The effect of lithium on AMPAR mEPSC could not be reproduced by individual inhibitions of biochemical effectors but by multiple inhibitions. Thus, the study done here underscores the need to look at the manifold effect of lithium in an integrated way. The study also might have implications in understanding the CNS complications seen in patients taking lithium treatment and in babies perinatally exposed to lithium.

<p>  </p> <p>Polypharmacy in older adults presents several challenges, such as suboptimal therapeutic outcomes and increased adverse effects. Deprescribing, a clinically supervised process of decreasing dosage or stopping the medication when risks outweigh benefits, has emerged as one possible solution to these problems. However, the literature describing deprescribing intervention frameworks is heterogenous regarding targeted medications to deprescribe, population characteristics, clinical settings, and measured outcomes. This dissertation utilizes Linsky et al.'s deprescribing conceptual model, which details factors influencing decisions regarding initiating deprescribing interventions and their direct impact on the process. </p> <p>This dissertation utilizes a multimethod approach to investigate factors that facilitate and improve the deprescribing of anticholinergic medications for older adults, addressing gaps in this population's anticholinergic medication use. The three studies included in this dissertation provide a comprehensive understanding of deprescribing anticholinergic medications for this population, each contributing unique insights and results. </p> <p>The first study explores the feasibility of in-person and remote Home Medication Inventory Method (HMIM) approaches to evaluate over-the-counter (OTC) and prescription medication possession and use, including anticholinergics. Results demonstrate that both methods can accurately assess anticholinergic medication usage patterns, providing healthcare providers with reproducible methods and detailed medication profiles to make informed deprescribing decisions based on complete medication lists.</p> <p>The second study examined the intertwined roles of social determinants of health and health beliefs in predicting older adults' self-reported deprescribing behaviors, proposing the Deprescribing Health Belief Model (DeRx-HBM) framework that can be utilized for these efforts. These results emphasize the importance of considering these elements when creating a patient-centric and culturally sensitive intervention since they significantly shape deprescribing behaviors.</p> <p>In the third study, we explored the use of a symptom-specific scale for measuring the symptom burden in older adults during the deprescribing of anticholinergic medications prescribed for urinary incontinence, depression, and pain management. This research introduces a validated scale for assessing anticholinergic symptom burden prior to, throughout, and following the deprescribing attempt. The implementation of this scale has the potential to enhance the reproducibility and standardization of deprescribing decisions. Furthermore, it can improve communication between healthcare professionals and patients, as well as monitor the effectiveness of interventions during and after the deprescribing process.</p> <p>Collectively, these studies provide invaluable insights into factors influencing deprescribing decisions, obstacles to implementing deprescribing practices, and potential strategies to optimize medication management in older adults. The major takeaway from these studies is that addressing these factors leads to more informed decisions among healthcare professionals and patients - potentially leading to improved patient outcomes, ensure the ongoing effectiveness of deprescribing initiatives among older adults, and the promotion of health equity throughout the deprescribing process.</p>

<p dir="ltr"><b>Background</b></p><p dir="ltr">Heart failure (HF) is a chronic clinical syndrome characterized by symptoms including breathlessness, fatigue, swelling of the ankles, and signs such as edema pulmonary crackles etc. During HF, pathogenic mechanisms including hemodynamic overload, ventricular remodeling, aberrant calcium handling, excessive neurohormonal stimulation contribute to the worsening and progression of the condition. Ventricular arrhythmias are the common cause of sudden cardiac death (SCD) in HF patients.</p><p dir="ltr">Hyperactivation of the sympathetic nervous system (SNS), a characteristic of HF, causes an increase in circulating catecholamines which becomes detrimental to-adrenergic receptors (-AR) leading to signaling dysfunction, and decrease in contractility and the ionotropic reserve. Expression of calcium/calmodulin-dependent protein kinase II (CaMKII), a downstream effector of-AR and a key regulator of calcium homeostasis, has been shown to be enhanced in HF. CaMKII-mediated mechanisms have been demonstrated to contribute to cardiac remodeling, arrhythmias by pathological regulation of ion channels, and contractile dysfunction.</p><p dir="ltr">The human ether-a-go-go related gene (hERG) encodes the pore-forming subunit of the voltage-gated potassium channel that conduct the rapid component of the delayed rectifier potassium current, <i>I</i>_Kr. The gating kinetics of <i>I</i>_Krmakes it a crucial determinant of the duration of the plateau phase of atrial and ventricular action potential (AP). Reduced <i>I</i>_Kr density due to loss-of-function mutations or pharmacological blockage of hERG channels precipitate arrhythmias. Downregulation of <i>I</i>_Kr density and protein have been reported in HF. Recent studies suggest that microRNAs (miRNAs) are involved in pathological downregulation of hERG.</p><p dir="ltr">miRNA are small non-coding RNAs of approximately 22 nucleotides in length that function as gene expression regulatory elements by repression translation. Aberrant miRNA expression has associated with cancer, cardiovascular, autoimmune, and inflammatory disorders.</p><p dir="ltr"><b>Objective</b></p><p dir="ltr">The overarching objective of this study is to investigate the mechanisms of CaMKII-mediated regulation of hERG function, including assessment of an interplay with miR-362-3p during sustained β-AR stimulation. In Specific Aim 1, the effect of CaMKII activation through sustained β-AR stimulation on hERG function and miR-362-3p expression will be assessed. The mechanism of miR-362-3p upregulation will be evaluated in Specific Aim 2, and in Specific Aim 3, the interactome of miR-362-3p and binding sites will be characterized and predicted, respectively.</p><p dir="ltr"><b>Methods</b></p><p dir="ltr">Whole-cell, voltage clamp electrophysiology experiments were performed in HEK 293 cells stably expressing hERG (hERG-HEK) and both hERG and wild-type CaMKIIδ<br>(hERG/CaMKII-HEK) following treatment with isoproterenol for 48 hours, and after transfection with miR-362-3p. The effect of CaMKII activation on miR-362-3p was assessed using real-time quantitative polymerase chain reaction (RT-qPCR). Total RNA was isolated 48 hours after isoproterenol treatment and the TaqMan assay was used to reverse transcribe and analyze miR-362-3p expression. Cells were transfected with cJun siRNA and precursor miR-362-3p to assess the role of cJun miR-362-3p upregulation during sustained β-AR stimulation with isoproterenol. The interactome of miR-362-3p was assessed in both cell lines using enhanced crosslinking immunoprecipitation (eCLIP) assay. miR-362-3p binding sites were predicted using RNAStructure Duplexfold after identification of miR-362-3p chimeric molecules from eCLIP experiment. Interaction analysis was performed using GeneMania in Cytoscape to identify genes that were potentially downregulated by miR-362-3p and been reported to interact with hERG.</p><p dir="ltr"><b>Results</b></p><p dir="ltr">In Specific Aim 1, the effect of sustained β-AR stimulation on hERG currents and endogenous miR-362-3p was assessed in hERG-HEK and hERG/CaMKII-HEK cells. Using whole-cell voltage clamp electrophysiology, we demonstrated that 48 hours treatment with 100 nM isoproterenol reduced hERG currents in hERG/CaMKII-HEK cells (p = 0.032) but had no effect on the voltage dependence of activation (p = 0.61) relative to control vehicle. Isoproterenol treatment for 48 hours, however, had no effect on hERG currents (p = 0.58) and the voltage dependence of activation (p = 0.99) in hERG-HEK cells. The effect of sustained isoproterenol treatment on miR-362-3p was also assessed using RT-qPCR. In hERG/CaMKII cells, 48 hours isoproterenol treatment increased miR-362-3p expression (2.3 folds; p = 0.038) relative to control vehicle. hERG/CaMKII-HEK cells were also treated with 500 nM KN-93 or its inactive analogue, KN-92, in an attempt to reverse CaMKII effect on miR-362-3p expression. Treatment with KN-93 decreased miR-362-3p expression (0.5-fold; p = 0.002) relative KN-92 treatment. Isoproterenol treatment had no effect on miR-362-3p expression in hERG-HEK cells (p = 0.38).</p><p dir="ltr">The regulatory mechanism of miR-362-3p expression was evaluated in Specific Aim 2. The role of an activator protein-1 (AP-1)-like sequence located at 98 base pairs upstream of miR-362-3p transcription start site was probed using siRNA inhibition of cJun, a central protein of the AP-1 complex, and deletion of the site sequence. The effect of exogenous miR-362-3p on hERG currents were first assessed. Precursor miR-362-3p decreased hERG currents (p = 0.003) compared to control plasmid. The effect of CaMKII overexpression was also assessed on exogenous miR-363-3p expression. Isoproterenol treatment in hERG/CaMKII-HEK cells transfected with precursor miR-362-3p increased mature miR-362-3p expression (0.029) compared to control vehicle treatment. Inhibition of cJun inhibition with cJun-specific siRNA decreased mature miR-362-3p expression (0.5-fold; p = 0.027) compared to scramble siRNA in hERG-HEK cells. In hERG-HEK cells transfected with mutated precursor miR-362-3p (AP-1-like site deleted), cJun inhibition with siRNA had no effect on miR-362-3p expression (p = 0.40).</p><p dir="ltr">The focus of Specific Aim 3 was to characterize the interactome of miR-362-3p as well as predict the miRNA response element (MRE) of its target mRNAs using enhanced crosslinking immunoprecipitation. A network analysis was also performed to identify miR-362-3p targets that have been reported to interact with hERG. Approximately 23% of miR-362-3p mRNA targets from the eCLIP assay have also been catalogued in miRNA database, TargetScanHuman, as miR-362-3p targets. miR-362-3p chimeric molecules with 853 unique targets, of which 75 were identified to interact with hERG through the network analysis. Four unique chimeric molecules between miR-362-3p and hERG mRNA were identified, but the interactions were non-canonical (located in the coding sequence of hERG and outside the seed region of miR-362-3p). Thirty five of the 75 miR-362-3p targets that were identified to interact had a chimeric read ≥ 3, a cutoff number indicating non-random chimeric formation. Using RNAStructure DuplexFold, miR-362-3p was predicted to form canonical binding with 12 of 35 mRNA targets. HSPA4, a heat shock protein involved in the maturation and trafficking of hERG, was identified in a canonical interaction (8-mer) with miR-362-3p.</p><p dir="ltr"><b>Conclusion</b>:</p><p dir="ltr">Sustained β-AR stimulation increases miR-362-3p expression and decreases hERG currents in CaMKII overexpressing cells. cJun mediates miR-362-3p upregulation by interacting with an AP-1-like sequence upstream of miR-362-3p transcription start site. Pathological regulation of <i>I</i>_Kr by CaMKII mediated by miR-362-3p during sustained-AR may contribute to increased risk of arrhythmias in states of increase catecholaminergic activity, such as HF.</p>

<p>Despite advancements in therapies, such as surgery, irradiation (IR) and chemotherapy, outcome for patients suffering from glioblastoma (GBM) remains fatal; the median survival time is only about 15 months. Even with novel therapeutic targets, networks and signaling pathways being discovered, monotherapy with such agents targeting such pathways has been disappointing in clinical trials. Poor prognosis for GBM can be attributed to several factors, including failure of drugs to cross the blood-brain-barrier (BBB), tumor heterogeneity, invasiveness, and angiogenesis. Development of tumor resistance, particularly to temozolomide (TMZ) and IR, creates a substantial clinical challenge.</p><p> </p><p>The primary focus of the work described herein was to develop a modeling and simulation approach that could be applied to rationally develop novel combination therapies and dose regimens that mitigate resistance development. Specifically, TMZ was combined with small molecule inhibitors that are either currently in clinical trials or are approved drugs for other cancer types, and which target the disease at various resistance signaling pathways that are induced in response to TMZ monotherapy. To accomplish this objective, an integrated PKPD modeling approach was used. A PK model for each drug was first defined. PK models were subsequently linked to a PD model description of tumor growth dynamics in the presence of a single drug or combinations of drugs. A key outcome of these combined PKPD models was tumor static concentration (TSC) curves of TMZ in combination with small molecule inhibitors that identify combination drug exposures predicted to arrest tumor growth. This approach was applied to TMZ in combination with abemaciclib (a dual CDK4/6 small molecule inhibitor) based on data from a published study evaluating abemaciclib (ACB) efficacy in combination with TMZ in a U87 GBM xenograft model. TSC was also constructed for TMZ in combination with RG7388 (MDM2 inhibitor) based on the data from an in-vivo study that evaluated effects on tumor growth suppression of these small molecule inhibitors in combination with TMZ in GBM 10 patient derived xenografts.</p><p>In GBM 43 mouse xenografts, emergence of resistance to TMZ treatment was identified. Thus, a resistance integrated PKPD model was developed to predict tumor growth kinetics after treatment with TMZ in GBM 43 tumors. Population PK models in immune deficient NOD.Cg-<em>Prkdc^scid Il2rg^tm1Wjl</em>/SzJ (NSG) mice for TMZ and small molecule inhibitors (GDC0068/RG7112) were developed based on a combination of data obtained from an in-vivo study and published sources. Subsequently, PK models were linked to tumor volume data obtained from GBM 43 subcutaneous xenografts. Model parameters quantifying tumor volume dynamics were precisely estimated (coefficient of variation < 40%) compared to a base tumor growth inhibition model in GBM 43 that did not incorporate resistance development. Graphical diagnostics of the resistance incorporated PKPD tumor growth inhibition model demonstrated a superior fit compared to the base model, and accurately captured the emergence of resistance to the TMZ monotherapy treatment observed in the GBM 43 patient derived xenograft model.</p>

<p>The following thesis will focus on understanding the downstream behavioral effects of δORmediated β-arrestinsignaling. δORagonists have been implicated as effective targets for a variety of diseases, however detrimental side effects of opioid-targeting agonists limit their clinical use. δORagonists specifically can induce seizures, however the underlying mechanism contributing to this  behavior  is  unknown.  We  review  this  phenomenon  in  more  detail,  highlighting  current agonists known to induce seizures and potential circuits and pathways involved. Our work suggests β-arrestinsignaling  is  involved,  specifically β-arrestin2  mediated  signaling  may  be  largely contributing  to δORagonist-induced  seizure  behavior.  As  it  is  possible  the β-arrestinisoforms have unique roles in seizure behavior, we also analyzed methods in which to provoke β-arrestinisoform bias of δORtargeting compounds. Though the full mechanism relating δORagonists with seizures remains unknown, our work provides foundational detail of this behavior, implicating the importance of β-arrestinisoform signaling through δOR; allowing for future studies to full define this seizure pathway and develop δORsafer agonists.  </p>

<p>Biotherapeutic compounds such as monoclonal antibodies help millions of people worldwide.  Currently, one of the most popular ways to deliver these compounds is via subcutaneous (SC)  injection. While it is understood that SC drug delivery does change with respect to injection  location, it is not understood why, as how the composition of SC changes as a function of location  is unknown. In this study, liquid chromatography mass spectrometry was used to understand and  describe how the SC tissue space changes on a molecular level. SC tissue from three different  locations, belly, breast, and behind the ear, of Yucatan minipigs was harvested and analyzed to  understand if and how SC tissue changes when anatomical location changes. It was determined  that there were distinct differences between the proteins identified in the three anatomical  locations. These differences included differences in relative cell populations, indicating that  different anatomical locations of SC tissue have different functions. Additionally, an ex vivo human SC tissue model was used to identify a core human proteome, as well as determine  compositional differences between female and male SC tissues. This model was also compared to  the Yucatan minipig model to determine compositional similarities between all groups. Finally,  proteomics were also used to ascertain whether the mass of SC tissue used affected the proteomic  results of the sample. These results indicated that human SC identifies the same number of proteins  down to samples of 10mg. This information can be used to design a proteomic experiment that  uses core needle biopsies to determine what gauge needle should be used in a wide scale clinical  study characterizing the human SC proteome. </p>