The effects of CaMKII signaling on neuronal viability

Indiana University-Purdue University Indianapolis (IUPUI).Calcium/calmodulin-dependent protein kinase II (CaMKII) is a critical modulator of synaptic function, plasticity, and learning and memory. In neurons and astrocytes, CaMKII regulates cellular excitability, cytoskeletal structure, and cell metabolism. A rapid increase in CaMKII activity is observed within the first few minutes of ischemic stroke in vivo; this calcium-dependent process is also observed following glutamate stimulation in vitro. Activation of CaMKII during pathological conditions is immediately followed by inactivation and aggregation of the kinase. The extent of CaMKII inactivation is directly correlated with the extent of neuronal damage. The studies presented here show that these fluctuations in CaMKII activity are not correlated with neuronal death; rather, they play a causal role in neuronal death. Pharmacological inhibition of CaMKII in the time immediately surrounding glutamate insult protects cultured cortical neurons from excitotoxicity. Interestingly, pharmacological inhibition of CaMKII during excitotoxic insult also prevents the aggregation and prolonged inactivation of the kinase, suggesting that CaMKII activity during excitotoxic glutamate signaling is detrimental to neuronal viability because it leads to a prolonged loss of CaMKII activity, culminating in neuronal death. In support of this, CaMKII inhibition in the absence of excitotoxic insult induces cortical neuron apoptosis by dysregulating intracellular calcium homeostasis and increasing excitatory glutamate signaling. Blockade of the NMDA-receptors and enzymatic degradation of the extracellular glutamate signal affords neuroprotection from CaMKII inhibition-induced toxicity. Co-cultures of neurons and glutamate-buffering astrocytes also exhibit this slow-induced excitotoxicity, as CaMKII inhibitors reduce glutamate uptake within the astrocytes. CaMKII inhibition also dysregulates calcium homeostasis in astrocytes and leads to increased ATP release, which was neurotoxic when applied to naïve cortical neurons. Together, these findings indicate that during aberrant calcium signaling, the activation of CaMKII is toxic because it supports aggregation and prolonged inactivation of the kinase. Without CaMKII activity, neurons and astrocytes release stores of transmitters that further exacerbate neuronal toxicity

HIV-1 Tat Promotes Age-Related Cognitive, Anxiety-like, and Antinociceptive Impairments in Mice that are Moderated by Aging Endocrine Status

Graduate students: Alaa N. Qrareya, Department of BioMolecular Sciences, School of Pharmacy; Fakhri Mahdi, Department of BioMolecular Sciences, School of Pharmacy; Marc Kaufman, Translational Imaging Center, The McLean Hospital, Department of Psychiatry, Harvard University; Nicole M. Ashpole, Department of BioMolecular Sciences, Research Institute of Pharmaceutical ScienceMajor/Minor: Major: Biology, Neuroscience MinorFaculty advisor: Jason J. Paris, Department of BioMolecular Sciences,Research Institute of Pharmaceutical Science, School of Pharmacyhttps://egrove.olemiss.edu/neuro_showcase/1008/thumbnail.jp

R02. HIV-1 Tat Promotes Age-Related Anxiety-like, Antinociceptive, and Neuromuscular Impairments in Aged Male Mice

Corresponding author (BioMolecular Sciences): Alaa Qrareya, [email protected]://egrove.olemiss.edu/pharm_annual_posters/1001/thumbnail.jp

Small molecule inhibitors of PSD95-nNOS protein-protein interactions as novel analgesics.

Aberrant increases in NMDA receptor (NMDAR) signaling contributes to central nervous system sensitization and chronic pain by activating neuronal nitric oxide synthase (nNOS) and generating nitric oxide (NO). Because the scaffolding protein postsynaptic density 95kDA (PSD95) tethers nNOS to NMDARs, the PSD95-nNOS complex represents a therapeutic target. Small molecule inhibitors IC87201 (EC5O: 23.94 µM) and ZL006 (EC50: 12.88 µM) directly inhibited binding of purified PSD95 and nNOS proteins in AlphaScreen without altering binding of PSD95 to ErbB4. Bot

R10. First in class (S,E)-11-[2-(arylmethylene)hydrazono]-PBD analogs as selective CB2 modulators targeting neurodegenerative disorders

Corresponding author (NCNPR): Mohamed A. Ibrahim, [email protected]://egrove.olemiss.edu/pharm_annual_posters/1009/thumbnail.jp

Effective inhibition of SARS-CoV-2 entry by heparin and enoxaparin derivatives

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) has caused a pandemic of historic proportions and continues to spread globally, with enormous consequences to human health. Currently there is no vaccine, effective therapeutic, or prophylactic. As with other betacoronaviruses, attachment and entry of SARS-CoV-2 are mediated by the spike glycoprotein (SGP). In addition to its well-documented interaction with its receptor, human angiotensin-converting enzyme 2 (hACE2), SGP has been found to bind to glycosaminoglycans like heparan sulfate, which is found on the surface of virtually all mammalian cells. Here, we pseudotyped SARS-CoV-2 SGP on a third-generation lentiviral (pLV) vector and tested the impact of various sulfated polysaccharides on transduction efficiency in mammalian cells. The pLV vector pseudotyped SGP efficiently and produced high titers on HEK293T cells. Various sulfated polysaccharides potently neutralized pLV-S pseudotyped virus with clear structure-based differences in antiviral activity and affinity to SGP. Concentration-response curves showed that pLV-S particles were efficiently neutralized by a range of concentrations of unfractionated heparin (UFH), enoxaparin, 6-O-desulfated UFH, and 6-O-desulfated enoxaparin with 50% inhibitory concentrations (IC50s) of 5.99mg/liter, 1.08mg/liter, 1.77mg/liter, and 5.86mg/liter, respectively. In summary, several sulfated polysaccharides show potent anti-SARS-CoV-2 activity and can be developed for prophylactic as well as therapeutic purposes. IMPORTANCE The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV-2) in Wuhan, China, in late 2019 and its subsequent spread to the rest of the world has created a pandemic situation unprecedented in modern history. While ACE2 has been identified as the viral receptor, cellular polysaccharides have also been implicated in virus entry. The SARS-CoV-2 spike glycoprotein (SGP) binds to glycosaminoglycans like heparan sulfate, which is found on the surface of virtually all mammalian cells. Here, we report structure-based differences in antiviral activity and affinity to SGP for several sulfated polysaccharides, including both well-characterized FDA-approved drugs and novel marine sulfated polysaccharides, which can be developed for prophylactic as well as therapeutic purposes

Visualization of conventional outflow tissue responses to netarsudil in living mouse eyes

AbstractVisual impairment due to glaucoma currently impacts 70 million people worldwide. While disease progression can be slowed or stopped with effective lowering of intraocular pressure, current medical treatments are often inadequate. Fortunately, three new classes of therapeutics that target the diseased conventional outflow tissue responsible for ocular hypertension are in the final stages of human testing. The rho kinase inhibitors have proven particularly efficacious and additive to current therapies. Unfortunately, non-contact technology that monitors the health of outflow tissue and its response to conventional outflow therapy is not available clinically. Using optical coherence tomographic (OCT) imaging and novel segmentation software, we present the first demonstration of drug effects on conventional outflow tissues in living eyes. Topical netarsudil (formerly AR-13324), a rho kinase/ norepinephrine transporter inhibitor, affected both proximal (trabecular meshwork and Schlemm’s Canal) and distal portions (intrascleral vessels) of the mouse conventional outflow tract. Hence, increased perfusion of outflow tissues was reliably resolved by OCT as widening of the trabecular meshwork and significant increases in cross-sectional area of Schlemm’s canal following netarsudil treatment. These changes occurred in conjunction with increased outflow facility, increased speckle variance intensity of outflow vessels, increased tracer deposition in conventional outflow tissues and decreased intraocular pressure. This is the first report using live imaging to show real-time drug effects on conventional outflow tissues and specifically the mechanism of action of netarsudil in mouse eyes. Advancements here pave the way for development of a clinic-friendly OCT platform for monitoring glaucoma therapy

Age-related Neuroendocrine, Cognitive, and Behavioral Co-Morbidities Are Promoted by HIV-1 Tat Expression in Male Mice

Presenter: Alaa Qraeyahttps://egrove.olemiss.edu/pharm_annual_posters_2021/1004/thumbnail.jp

Age-dependent hormesis-like effects of the synthetic cannabinoid CP55940 in C57BL/6 mice

Abstract Use of cannabis and cannabinoid-containing substances is increasing among geriatric patients, despite relatively sparse preclinical evidence in aged models. To better understand the effects of exogenous cannabinoids on aging male and female rodents, we compared the age- and dose-dependent physiological and behavioral effects of the synthetic cannabinoid CP55940 in young–adult and aged C57BL/6 mice. Locomotion, body temperature, thermal nociception, and fecal output were measured following CP55940 administration. Our findings indicate that CP55940 is more potent and efficacious in older mice, evidenced by exaggerated antinociception and locomotor inhibition when compared to younger adult mice. In addition, we report that low doses of CP55940 paradoxically stimulate locomotion in young–adult (4 m) mice; however, this hormesis-like response is not as evident in aged animals (21–24 m). These bidirectional effects appear to be mediated via the endocannabinoid CB1 and CB2 receptors