Vol 5-3 Mini Review

Microtubule Electrical Oscillations and Hippocampal Function

Maria del Rocio Cantero, Horacio F. Cantiello

Laboratorio de Canales Iónicos, Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD, CONICET-UNSE) Santiago del Estero, Argentina

Microtubules (MTs) are long cylindrical structures of the cytoskeleton that control cell division, vesicular transport, and the shape of cells. MTs are highly charged and behave as nonlinear electrical transmission lines. However, comparatively little is known about the role(s) these nonlinear electrical properties of MTs play in cell function. MTs form bundles, which are particularly prominent in neurons, where they help developmentally define axons and dendrites. The present review summarizes recent work from our laboratory which demonstrated that 1) bundles of rat brain MTs spontaneously generate electrical oscillations and bursts of electrical activity similar to action potentials; 2) actin filaments control electrostatically the oscillatory response of brain MTs; and 3) neurites of cultured mouse hippocampal neurons generate and propagate electrical oscillations thus, providing a cellular correlate to the isolated MT oscillations. Electrical oscillations are an intrinsic property of brain MT bundles, which may have important implications in the control of various neuronal functions, including a contribution to the intrinsic oscillatory modes of neurons, and thus to higher brain functions, including the formation of memory and the onset of consciousness.

DOI: 10.29245/2572.942X/2020/3.1267 View / Download Pdf
Vol 5-3 Research Article

Gulf War Illness: C-Reactive Protein is Associated with Reduction of the Volume of Hippocampus and Decreased Fractional Anisotropy of the Fornix

Peka Christova1,2, Lisa M. James1,2,3, Adam F. Carpenter1,4, Scott M. Lewis1,4, Rachel A. Johnson1, Brian E. Engdahl1,2,5, Apostolos P. Georgopoulos1,2,3,4*

1Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN, 55417, USA

2Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA

3Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN 55455, US

4Department of Neurology, University of Minnesota Medical School, Minneapolis, MN 55455, USA

5Department of Psychology, University of Minnesota Medical School, Minneapolis, MN 55455, USA

Memory and mood impairments are among the most commonly reported symptoms in veterans with Gulf War Illness (GWI), suggesting hippocampal involvement. Several studies have also documented evidence of inflammation in GWI. The aim of the present study was to evaluate the association between C-reactive protein (CRP), a marker of inflammation, and hippocampal volume and microstructural alterations of its major output, the fornix. Sixty-three veterans with GWI provided blood samples for evaluation of CRP and underwent a 3T magnetic resonance imaging scan from which hippocampal volume and fornix fractional anisotropy (FA) were obtained. Results demonstrated that CRP was significantly and negatively associated with hippocampal volume and fornix FA in GWI. Given the known closely interwoven associations between inflammation and neurodegeneration, it is possible that the effects we observed could be due to neurodegeneration, secondary to chronic neuroinflammation. Finally, given the known association of hippocampus to memory and mood disorders, our findings provide new insights into memory and mood alterations associated with GWI.

DOI: 10.29245/2572.942X/2020/3.1272 View / Download Pdf
Vol 5-3 Research Article

Human Leukocyte Antigen (HLA) Alleles Prevent Metabolically-Induced Inflammation and Cerebrocortical Thinning in Gulf War Illness

Peka Christova1,2, Lisa M. James1,2,3, Adam F. Carpenter1,4, Scott M. Lewis1,4, Brian E. Engdahl1,5, Apostolos P. Georgopoulos1,2,3,4*

1Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN, 55417, USA

2Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA

3Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN 55455, USA

4Department of Neurology, University of Minnesota Medical School, Minneapolis, MN 55455, USA

5Department of Psychology, University of Minnesota Medical School, Minneapolis, MN 55455, USA

Independent lines of research have demonstrated that GWI is associated with elevated inflammatory markers, metabolic disruptions, and alterations in brain morphometry. Possessing specific Class II human leukocyte antigen (HLA) alleles, on the other hand, has been shown to protect against GWI and to be inversely associated with symptom severity in a dose-dependent manner. The aim of the present study was to evaluate the association between C-reactive protein (CRP), a marker of inflammation, body mass index (BMI), and brain morphometry in GWI veterans with and without a protective HLA allele. Sixty-three veterans with GWI provided blood samples for evaluation of CRP and HLA, height and weight for calculating BMI, and underwent a 3T magnetic resonance imaging scan from which the volume, surface area, and cortical thickness of 68 cortical regions of interest (ROI) were determined. Results demonstrated that the CRP was highly significantly associated with BMI and cortical thinning in veterans lacking protective HLA alleles but not in those possessing a protective HLA allele. Given the role of HLA in antibody production against foreign antigens, the findings suggest that persistent foreign antigens stemming from lack of immunogenetic protection against them contribute to inflammation, metabolic disruption, and cortical thinning in GWI. The findings are discussed in terms of GW-related exposures that are known to result in inflammation.

DOI: 10.29245/2572.942X/2020/3.1273 View / Download Pdf