THE ROLE OF MICROTUBULE-ASSOCIATED PROTEIN TAU IN NEURONAL EXCITABILITY AND EPILEPTOGENESIS

Tauopathies, including Alzheimer’s disease (AD), are devastating diseases with an immense burden on society which is predicted to increase in coming decades. In addition to progressive loss of memory and cognitive function, patients with tauopathies have a 6-10 fold increase in lifetime risk for seizures, and many are diagnosed with epilepsy. The presence of epileptiform activity on electroencephalogram (EEG) recordings from patients with AD predicts faster cognitive decline compared to patients without abnormal EEG readings. Electrophysiological measurements in murine models of AD have identified neuronal hyperexcitability. Furthermore, reducing tau phosphorylation or expression confers seizure resistance in animal epilepsy models. Although evidence suggests the presence of common mechanisms contributing to both tauopathy and epilepsy, more work is needed to understand how this interaction works and whether tau can be effectively targeted to improve patients’ lives. This study investigated the relationship between tauopathy using transgenic mice that expressed no tau protein (tau-/-) or expressed non-mutant, human tau protein without expressing murine tau (htau). The htau mice develop progressive tauopathy with age. Non-transgenic C57BL/6J mice were used as controls. Whole-cell patch-clamp electrophysiology was used to define tau’s role in neuronal excitability in vivo in dentate gyrus granule cells. Both transgenic mouse strains exhibited a lower frequency of evoked action potentials and reduced likelihood of neurotransmitter release from perforant pathway inputs as measured by the paired pulse ratio compared to control at 1.5 months of age, but these differences were lost with age. The similarities between the tau-/- and htau mice suggest that hyperexcitability is related to the amount of normally functioning tau rather than the presence of pathological tau, and that the presence of normal murine tau may influence the results of other studies involving models of tauopathy. Furthermore, tau’s role in epileptogenesis was studied using intrahippocampal injection of kainate (i.ie., IHK) to induce status epilepticus, a model that induces temporal lobe epileptogenesis, in tau-/-, htau, and C57BL/6J mice. The process of epileptogenesis appeared to be modified compared to control in both transgenic strains, but did not appear to be prevented. Compared to either tau-/- or C57BL/6J mice, htau mice experienced significantly greater mortality after IHK. Modifications in tau expression, wither deletion or humanization, partially abrogated synaptic excitability that developed following IHK. In conclusion, this study showed that neuronal excitability is affected similarly by either deletion or humanization of tau, with the notable exception of survival after IHK. This study provides clearer understanding of tau’s role in acquired epilepsy and suggests novel therapeutics targeting tau may be effective for the treatment of epilepsy

Manganese-Enhanced Magnetic Resonance Imaging: Overview and Central Nervous System Applications With a Focus on Neurodegeneration

Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and the brief but decorated clinical usage of chelated manganese compound mangafodipir in humans

Manganese-Enhanced Magnetic Resonance Imaging: Overview and Central Nervous System Applications With a Focus on Neurodegeneration

Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and the brief but decorated clinical usage of chelated manganese compound mangafodipir in humans

Manganese-Enhanced Magnetic Resonance Imaging: Overview and Central Nervous System Applications With a Focus on Neurodegeneration

Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and the brief but decorated clinical usage of chelated manganese compound mangafodipir in humans

Q134R: Small chemical compound with NFAT inhibitory properties improves behavioral performance and synapse function in mouse models of amyloid pathology

Inhibition of the protein phosphatase calcineurin (CN) ameliorates pathophysiologic and cognitive changes in aging rodents and mice with aging-related Alzheimer's disease (AD)-like pathology. However, concerns over adverse effects have slowed the transition of common CN-inhibiting drugs to the clinic for the treatment of AD and AD-related disorders. Targeting substrates of CN, like the nuclear factor of activated T cells (NFATs), has been suggested as an alternative, safer approach to CN inhibitors. However, small chemical inhibitors of NFATs have only rarely been described. Here, we investigate a newly developed neuroprotective hydroxyquinoline derivative (Q134R) that suppresses NFAT signaling, without inhibiting CN activity. Q134R partially inhibited NFAT activity in primary rat astrocytes, but did not prevent CN-mediated dephosphorylation of a non-NFAT target, either in vivo, or in vitro. Acute (= 3 months) oral delivery of Q134R appeared to be safe, and, in fact, promoted survival in wild-type (WT) mice when given for many months beyond middle age. Finally, chronic delivery of Q134R to APP/PS1 mice during the early stages of amyloid pathology (i.e., between 6 and 9 months) tended to reduce signs of glial reactivity, prevented the upregulation of astrocytic NFAT4, and ameliorated deficits in synaptic strength and plasticity, without noticeably altering parenchymal A beta plaque pathology. The results suggest that Q134R is a promising drug for treating AD and aging-related disorders

Q134R: Small Chemical Compound with NFAT Inhibitory Properties Improves Behavioral Performance and Synapse Function in Mouse Models of Amyloid Pathology

Inhibition of the protein phosphatase calcineurin (CN) ameliorates pathophysiologic and cognitive changes in aging rodents and mice with aging-related Alzheimer\u27s disease (AD)-like pathology. However, concerns over adverse effects have slowed the transition of common CN-inhibiting drugs to the clinic for the treatment of AD and AD-related disorders. Targeting substrates of CN, like the nuclear factor of activated T cells (NFATs), has been suggested as an alternative, safer approach to CN inhibitors. However, small chemical inhibitors of NFATs have only rarely been described. Here, we investigate a newly developed neuroprotective hydroxyquinoline derivative (Q134R) that suppresses NFAT signaling, without inhibiting CN activity. Q134R partially inhibited NFAT activity in primary rat astrocytes, but did not prevent CN-mediated dephosphorylation of a non-NFAT target, either in vivo, or in vitro. Acute (≤1 week) oral delivery of Q134R to APP/PS1 (12 months old) or wild-type mice (3–4 months old) infused with oligomeric Aβ peptides led to improved Y maze performance. Chronic (≥3 months) oral delivery of Q134R appeared to be safe, and, in fact, promoted survival in wild-type (WT) mice when given for many months beyond middle age. Finally, chronic delivery of Q134R to APP/PS1 mice during the early stages of amyloid pathology (i.e., between 6 and 9 months) tended to reduce signs of glial reactivity, prevented the upregulation of astrocytic NFAT4, and ameliorated deficits in synaptic strength and plasticity, without noticeably altering parenchymal Aβ plaque pathology. The results suggest that Q134R is a promising drug for treating AD and aging-related disorders

Broad Kinase Inhibition Mitigates Early Neuronal Dysfunction in Tauopathy

Tauopathies are a group of more than twenty known disorders that involve progressive neurodegeneration, cognitive decline and pathological tau accumulation. Current therapeutic strategies provide only limited, late-stage symptomatic treatment. This is partly due to lack of understanding of the molecular mechanisms linking tau and cellular dysfunction, especially during the early stages of disease progression. In this study, we treated early stage tau transgenic mice with a multi-target kinase inhibitor to identify novel substrates that contribute to cognitive impairment and exhibit therapeutic potential. Drug treatment significantly ameliorated brain atrophy and cognitive function as determined by behavioral testing and a sensitive imaging technique called manganese-enhanced magnetic resonance imaging (MEMRI) with quantitative R1 mapping. Surprisingly, these benefits occurred despite unchanged hyperphosphorylated tau levels. To elucidate the mechanism behind these improved cognitive outcomes, we performed quantitative proteomics to determine the altered protein network during this early stage in tauopathy and compare this model with the human Alzheimer’s disease (AD) proteome. We identified a cluster of preserved pathways shared with human tauopathy with striking potential for broad multi-target kinase intervention. We further report high confidence candidate proteins as novel therapeutically relevant targets for the treatment of tauopathy. Proteomics data are available via ProteomeXchange with identifier PXD023562

Manganese-Enhanced Magnetic Resonance Imaging: Overview and Central Nervous System Applications With a Focus on Neurodegeneration

Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and the brief but decorated clinical usage of chelated manganese compound mangafodipir in humans

Comparison of open and closed hyperthermic intraperitoneal chemotherapy: Results from the United States hyperthermic intraperitoneal chemotherapy collaborative.

BackgroundCytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) for peritoneal carcinomatosis can be performed in two ways: Open or closed abdominal technique.AimTo evaluate the impact of HIPEC method on post-operative and long-term survival outcomes.MethodsPatients undergoing CRS with HIPEC from 2000-2017 were identified in the United States HIPEC collaborative database. Post-operative, recurrence, and overall survival outcomes were compared between those who received open vs closed HIPEC.ResultsOf the 1812 patients undergoing curative-intent CRS and HIPEC, 372 (21%) patients underwent open HIPEC and 1440 (79%) underwent closed HIPEC. There was no difference in re-operation or severe complications between the two groups. Closed HIPEC had higher rates of 90-d readmission while open HIPEC had a higher rate of 90-d mortalities. On multi-variable analysis, closed HIPEC technique was not a significant predictor for overall survival (hazards ratio: 0.75, 95% confidence interval: 0.51-1.10, P = 0.14) or recurrence-free survival (hazards ratio: 1.39, 95% confidence interval: 1.00-1.93, P = 0.05) in the entire cohort. These findings remained consistent in the appendiceal and the colorectal subgroups.ConclusionIn this multi-institutional analysis, the HIPEC method was not independently associated with relevant post-operative or long-term outcomes. HIPEC technique may be left to the discretion of the operating surgeon