Mark Wojnarowicz

Chronic Traumatic Encephalopathy in Blast-Exposed Military Veterans and a Blast Neurotrauma Mouse Model

Blast exposure is associated with chronic traumatic encephalopathy, impaired neuronal function, and persistent cognitive deficits in blast-exposed military veterans and experimental animals. Blast Brain: An Invisible Injury Revealed Traumatic brain injury (TBI) is the “signature” injury of the conflicts in Afghanistan and Iraq and is associated with psychiatric symptoms and long-term cognitive disability. Recent estimates indicate that TBI may affect 20% of the 2.3 million U.S. servicemen and women deployed since 2001. Chronic traumatic encephalopathy (CTE), a tau protein–linked neurodegenerative disorder reported in athletes with multiple concussions, shares clinical features with TBI in military personnel exposed to explosive blast. However, the connection between TBI and CTE has not been explored in depth. In a new study, Goldstein et al. investigate this connection in the first case series of postmortem brains from U.S. military veterans with blast exposure and/or concussive injury. They report evidence for CTE neuropathology in the military veteran brains that is similar to that observed in the brains of young amateur American football players and a professional wrestler. The investigators developed a mouse model of blast neurotrauma that mimics typical blast conditions associated with military blast injury and discovered that blast-exposed mice also demonstrate CTE neuropathology, including tau protein hyperphosphorylation, myelinated axonopathy, microvascular damage, chronic neuroinflammation, and neurodegeneration. Surprisingly, blast-exposed mice developed CTE neuropathology within 2 weeks after exposure to a single blast. In addition, the neuropathology was accompanied by functional deficits, including slowed axonal conduction, reduced activity-dependent long-term synaptic plasticity, and impaired spatial learning and memory that persisted for 1 month after exposure to a single blast. The investigators then showed that blast winds with velocities of more than 330 miles/hour—greater than the most intense wind gust ever recorded on earth—induced oscillating head acceleration of sufficient intensity to injure the brain. The researchers then demonstrated that blast-induced learning and memory deficits in the mice were reduced by immobilizing the head during blast exposure. These findings provide a direct connection between blast TBI and CTE and indicate a primary role for blast wind–induced head acceleration in blast-related neurotrauma and its aftermath. This study also validates a new blast neurotrauma mouse model that will be useful for developing new diagnostics, therapeutics, and rehabilitative strategies for treating blast-related TBI and CTE. Blast exposure is associated with traumatic brain injury (TBI), neuropsychiatric symptoms, and long-term cognitive disability. We examined a case series of postmortem brains from U.S. military veterans exposed to blast and/or concussive injury. We found evidence of chronic traumatic encephalopathy (CTE), a tau protein–linked neurodegenerative disease, that was similar to the CTE neuropathology observed in young amateur American football players and a professional wrestler with histories of concussive injuries. We developed a blast neurotrauma mouse model that recapitulated CTE-linked neuropathology in wild-type C57BL/6 mice 2 weeks after exposure to a single blast. Blast-exposed mice demonstrated phosphorylated tauopathy, myelinated axonopathy, microvasculopathy, chronic neuroinflammation, and neurodegeneration in the absence of macroscopic tissue damage or hemorrhage. Blast exposure induced persistent hippocampal-dependent learning and memory deficits that persisted for at least 1 month and correlated with impaired axonal conduction and defective activity-dependent long-term potentiation of synaptic transmission. Intracerebral pressure recordings demonstrated that shock waves traversed the mouse brain with minimal change and without thoracic contributions. Kinematic analysis revealed blast-induced head oscillation at accelerations sufficient to cause brain injury. Head immobilization during blast exposure prevented blast-induced learning and memory deficits. The contribution of blast wind to injurious head acceleration may be a primary injury mechanism leading to blast-related TBI and CTE. These results identify common pathogenic determinants leading to CTE in blast-exposed military veterans and head-injured athletes and additionally provide mechanistic evidence linking blast exposure to persistent impairments in neurophysiological function, learning, and memory.

Roles of the 15-kDa selenoprotein (Sep15) in redox homeostasis and cataract development revealed by the analysis of Sep 15 knockout mice.

The 15-kDa selenoprotein (Sep15) is a thioredoxin-like, endoplasmic reticulum-resident protein involved in the quality control of glycoprotein folding through its interaction with UDP-glucose:glycoprotein glucosyltransferase. Expression of Sep15 is regulated by dietary selenium and the unfolded protein response, but its specific function is not known. In this study, we developed and characterized Sep15 KO mice by targeted removal of exon 2 of the Sep15 gene coding for the cysteine-rich UDP-glucose:glycoprotein glucosyltransferase-binding domain. These KO mice synthesized a mutant mRNA, but the shortened protein product could be detected neither in tissues nor in Sep15 KO embryonic fibroblasts. Sep15 KO mice were viable and fertile, showed normal brain morphology, and did not activate endoplasmic reticulum stress pathways. However, parameters of oxidative stress were elevated in the livers of these mice. We found that Sep15 mRNA was enriched during lens development. Further phenotypic characterization of Sep15 KO mice revealed a prominent nuclear cataract that developed at an early age. These cataracts did not appear to be associated with severe oxidative stress or glucose dysregulation. We suggest that the cataracts resulted from an improper folding status of lens proteins caused by Sep15 deficiency.

Concussion, microvascular injury, and early tauopathy in young athletes after impact head injury and an impact concussion mouse model

The mechanisms underpinning concussion, traumatic brain injury (TBI) and chronic traumatic encephalopathy (CTE) are poorly understood. Using neuropathological analyses of brains from teenage athletes, a new mouse model of concussive impact injury, and computational simulations, Tagge et al. show that head injuries can induce TBI and early CTE pathologies independent of concussion.

Considerations for Experimental Animal Models of Concussion, Traumatic Brain Injury, and Chronic Traumatic Encephalopathy—These Matters Matter

Animal models of concussion, traumatic brain injury (TBI), and chronic traumatic encephalopathy (CTE) are widely available and routinely deployed in laboratories around the world. Effective animal modeling requires careful consideration of four basic principles. First, animal model use must be guided by clarity of definitions regarding the human disease or condition being modeled. Concussion, TBI, and CTE represent distinct clinical entities that require clear differentiation: concussion is a neurological syndrome, TBI is a neurological event, and CTE is a neurological disease. While these conditions are all associated with head injury, the pathophysiology, clinical course, and medical management of each are distinct. Investigators who use animal models of these conditions must take into account these clinical distinctions to avoid misinterpretation of results and category mistakes. Second, model selection must be grounded by clarity of purpose with respect to experimental questions and frame of reference of the investigation. Distinguishing injury context (“inputs”) from injury consequences (“outputs”) may be helpful during animal model selection, experimental design and execution, and interpretation of results. Vigilance is required to rout out, or rigorously control for, model artifacts with potential to interfere with primary endpoints. The widespread use of anesthetics in many animal models illustrates the many ways that model artifacts can confound preclinical results. Third, concordance between key features of the animal model and the human disease or condition being modeled is required to confirm model biofidelity. Fourth, experimental results observed in animals must be confirmed in human subjects for model validation. Adherence to these principles serves as a bulwark against flawed interpretation of results, study replication failure, and confusion in the field. Implementing these principles will advance basic science discovery and accelerate clinical translation to benefit people affected by concussion, TBI, and CTE.

Aβ-POTENTIATED AND Aβ-INDEPENDENT AGE RELATED CHANGES IN THE LENS OF THE EYE IN WILD-TYPE AND ALZHEIMER’S DISEASE MICE

primary neural cell culture. Results: We found that cognitive deficits in middle-aged PS1V97L trangenic AD mice were mainly caused by the accumulation of nonameric and dodecameric soluble Ab oligomers, which could be produced and duplicated in astrocytes to accelerate neuronal injury by activating b-secretase and apolipoprotein E. Conclusions: Taken together, our results suggest that the astrocytes could augment the production of nonamer and dodecamer leading to neuronal injury and cognitive deficits associated with AD. P1-192 Ab-POTENTIATEDANDAb-INDEPENDENT AGERELATEDCHANGES IN THE LENS OF THE EYE IN WILD-TYPE AND ALZHEIMER’S DISEASE MICE Juliet A. Moncaster, Mark W. Wojnarowicz, Rebecca Zeng, Olga Minaeva, Lee Goldstein, Boston University School of Medicine, Boston, MA, USA; Boston University, Boston, MA, USA. Contact e-mail: jmon@bu.edu

CONCUSSION, MICROVASCULAR INJURY, AND EARLY TAUOPATHY IN YOUNG ATHLETES AFTER IMPACT HEAD INJURY AND AN IMPACT CONCUSSION MOUSE MODEL

tauopathy in young athletes after impact head injury and an impact concussion mouse model 5 Chad A. Tagge,* Andrew M. Fisher,* Olga V. Minaeva,* Amanda GaudreauBalderrama, Juliet A. Moncaster, Xiao-Lei Zhang, Mark W. Wojnarowicz, Noel Casey, Haiyan Lu, Olga N. Kokiko-Cochran, Sudad Saman, Maria Ericsson, Kristen D. Onos, Ronel Veksler, Vladimir V. Senatorov, Jr, Asami Kondo, Xiao Z. Zhou, Omid Miry, Linnea R. Vose, Katisha R. Gopaul, Chirag Upreti, 10 Christopher J. Nowinski, Robert C. Cantu, Victor E. Alvarez, Audrey M. Hildebrandt, Erich S. Franz, Janusz Konrad, James A. Hamilton, Ning Hua, Yorghos Tripodis, Andrew T. Anderson, Gareth R. Howell, Daniela Kaufer, Garth F. Hall, Kun P. Lu, Richard M. Ransohoff,7,z Robin O. Cleveland, Neil W. Kowall, Thor D. Stein, Bruce T. Lamb, Bertrand R. Huber, 15 William C. Moss, Alon Friedman, Patric K. Stanton, Ann C. McKee, Lee E. Goldstein

Aβ-INDEPENDENT AND Aβ-POTENTIATED AGE-RELATED CHANGES IN THE LENS OF WILD-TYPE AND ALZHEIMER’S DISEASE TG2576 MICE

a Meso Scale Discovery SECTOR 6000. Results:All following results are presented as the average of day 100 and 200 6 standard error. Variation in absolute biomarker concentrations was within acceptable limits for Ab (7.9%CV60.5), but high for Ttau (16.8%CV61.8). Inductions of the same cell line displayed variation similar to that between cell lines. However, ratios of Ab peptides were highly consistent over time (3.4%CV60.3). All control lines secreted Ab in similar ratios (Ab42:40 1⁄4 0.16<0.1, Ab42:381⁄4 0.46<0.1, Ab40:381⁄4 4.06<0.1). Versus controls, APP cells demonstrated increased Ab42:40 (0.26<0.1), slightly increased Ab42:38 (0.56<0.1), and decreased Ab40:38 (2.56<0.1). PSEN1 intron 4 deletion cells had increased Ab42:40 (0.26<0.1), increased Ab42:38 (1.26<0.1) and increased Ab40:38 (5.36<0.1). PSEN1 M139V cells had increased Ab42:40 (0.26<0.1), increased Ab42:38 (0.96<0.1), and slightly increased Ab40:38 (4.46<0.1). Ab:T-tau ratios were highly variable (23.8% CV6<1.8) and yielded little distinction between cell lines, although tau decreased in relation to Ab over the time course. Conclusions: Human cortical neurons harbouring specific fAD mutations all increased Ab42:40 secretion into the extracellular space (by approximately two-fold) versus controls. The Ab40:38 ratio distinguished well between different mutations, and may shed light on the question of g-secretase cleavage pathways for the generation of Ab.

Mechanistic pathobiology of acute concussion, traumatic brain injury, and chronic traumatic encephalopathy in mouse models of blast neurotrauma and impact concussion

(active form), while had no effect on the level of Tyrosine-307phosphorylated PP-2A. Unexpectedly, 5-HT1A agonist 8-OHDPAT did not decrease forskolin-induced tau hyperphophorylation. Conclusions:Escitalopram could protect forskolin-induced tau hyperphosphorylation at multiple AD-related sites, and the mechanism involves inactivation of GSK-3b. Our findings suggest that escitalopram could be a promising therapeutic target for AD-like tau hyperphosphorylation, this may support a potential effective role of antidepressants, at least of the SSRI class, in the prevention of dementia associated with depression in patients.

Metallomic imaging mass and optical spectrometry (MIMOS) of the murine and human eye and brain in Alzheimer's disease and normal aging

correlation using conventional and advanced mri imaging techniques in differentiating the subtypes of progressive supranuclear palsy (PSP) i.e psp-p and psp richardson subtypes. Methods: This was a prospective study comprising of 24 patients of PSP (psp P 1⁄4 11 and psp-rs1⁄4 13) and 26 matched healthy controls. routine mri imaging and planimetry were used to diffrentiate.VBM analysis for both gray matter with t1 weighted image and white matter using DTI was performed.advanced TBSS analysis was also perfrmed and Fractionalanisotropy, mean diffusivity (MD), axial diffusivity, andradial diffusivity (RD) changes were studied in theWM of these PSP patients to identify relative severity of WM changes as well as identify spatial distribution of the differences. Clinicoradiological correlation was done to determine the strength of correlation between WM abnormalities.minerlarisation was also evaluated used r2 relaxometry. Results: The frontoparietal cerebral WM, thalamus, midbrain tectum,superior cerebellar peduncle, and cerebellar WM showed significant abnomality. Compared to PSP-P, the patients of PSP-RS had more spatial abnormalities localized to the frontal WM. Conclusions: PSP-RS showed more severe white matter abnormality compared to the PSP-P subtype.

High-resolution multi-elemental metallomic mapping of the human eye in Alzheimer's disease and normal aging

Background:We previously identified amyloid-b (Ab) deposition, amyloid pathology, and co-localizing supranuclear cataracts in the lens of the eye in Alzheimer’s disease (AD) and Down Syndrome (DS) [Goldstein, 2003; Moncaster, 2010]. Interaction of Ab and biometals represents a major pathogenic pathway in AD and provides the basis for clinical effective disease-modifying therapy (Duce and Bush, 2010; Lannfelt, 2008). To date, mapping the ocular metallome has been limited by technical barriers. Here we developed a new technique, High-Resolution Metallomic Imaging Mass Spectrometry (HR-MIMS), to perform the first high-resolution multielemental and isotopic distribution maps of the metallome of the adult human eye in AD and age-matched controls. Methods: Human eyes were obtained through the Boston University Alzheimer’s Disease Center and NDRI (Philadelphia, PA). Eyes were flash frozen and analyzed by metallomic imagingmass spectrometry (MIMSmapping) using a custom cryogenic cell coupled to nanosecond ultraviolet laser ablation (NULA) and hyphenated high-resolution magnetic sector field ICP-MS at the Boston University Center for Biometals & Metallomics, Boston, MA. Laser wavelength, 213 nm; rate, 5-50 mms-1; spot size: 10 micron (high resolution) to 100 micron (scanning resolution). MIMS analysis was conducted on surround to establish elemental background and calibrated with NIST standards. Results: High resolutionmetallomic maps generated fromAD and age-matched control eyes demonstrated unique elemental and isotopic distribution patterns. Zinc was confirmed in the subequatorial supranucleus of the lens, the same region implicated in AD-linked Ab accumulation and cataractogenesis. Retinal zinc demonstrated a laminar distribution corresponding to cytoarchitectonic organization. Retinal iron revealed a vascular distribution pattern. Simultaneous metallomic maps of the same lenses revealed distinctive elemental and isotopic distribution patterns for other important biometals, including copper (Cu), iron (Fe), selenium (Se), molybdenum (Mo), manganese (Mn), and other elements. Conclusions: We deployed HR-MIMS analysis to generate detailed quantitative high-resolution spatial distribution maps of essential and trace elements and isotopes in adult human eyes in AD and age-matched controls at 10-100 micron spatial resolution. This study strongly supports a role for zinc in AD-linked lens pathology.