%0 Journal Article %J J Alzheimers Dis %D 2018 %T VEGFR1 and VEGFR2 in Alzheimer's Disease. %A Harris, Rachel %A Miners, James Scott %A Allen, Shelley %A Love, Seth %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Brain %K Case-Control Studies %K Endothelial Cells %K Female %K Gene Expression Regulation %K Humans %K Male %K Middle Aged %K Neovascularization, Pathologic %K RNA, Messenger %K Signal Transduction %K Vascular Endothelial Growth Factor A %K Vascular Endothelial Growth Factor Receptor-1 %K Vascular Endothelial Growth Factor Receptor-2 %X

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor. Despite upregulation of VEGF in the brain in Alzheimer's disease (AD), probably in response to amyloid-β, vasoconstriction, and tissue hypoxia, there is no consequent increase in microvessel density. VEGF binds to and activates VEGF receptor 2 (VEGFR2), but also binds to VEGF receptor 1 (VEGFR1), which exists in less-active membrane-bound and inactive soluble (sVEGFR1) forms and inhibits pro-angiogenic signaling. We have investigated whether altered expression of VEGF receptors might account for the lack of angiogenic response to VEGF in AD. We assessed the cellular distribution and protein level of VEGFR1 and VEGFR2 in parietal cortex from 50 AD and 36 age-matched control brains, and related the findings to measurements of VEGF and von Willebrand factor level (a marker of microvessel density) in the same tissue samples. VEGFR2 was expressed by neurons, astrocytes and endothelial cells. VEGFR1 was expressed predominantly neuronally and was significantly reduced in AD (p = 0.02). Western blot analysis on a subset of brains showed reduction in VEGFR1:sVEGFR1 in AD (p = 0.046). The lack of angiogenesis despite cerebral hypoperfusion in AD is not explained by altered expression of VEGFR2 or total VEGFR1; indeed, the downregulation of VEGFR1 may represent a pro-angiogenic response to the hypoperfusion. However, the relative increase in sVEGFR1 would be expected to have an anti-angiogenic effect which may be a factor in AD.

%B J Alzheimers Dis %V 61 %P 741-752 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29226875?dopt=Abstract %R 10.3233/JAD-170745 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Effects of Hypertension and Anti-Hypertensive Treatment on Amyloid-β (Aβ) Plaque Load and Aβ-Synthesizing and Aβ-Degrading Enzymes in Frontal Cortex. %A Ashby, Emma L %A Miners, James S %A Kehoe, Patrick G %A Love, Seth %K Aged %K Aged, 80 and over %K Amyloid Precursor Protein Secretases %K Antihypertensive Agents %K Female %K Frontal Lobe %K Humans %K Hypertension %K Immunohistochemistry %K Insulysin %K Male %K Neprilysin %K Peptidyl-Dipeptidase A %K Plaque, Amyloid %K Retrospective Studies %X

Epidemiological data associate hypertension with a predisposition to Alzheimer's disease (AD), and a number of postmortem and in vivo studies also demonstrate that hypertension increases amyloid-β (Aβ) pathology. In contrast, anti-hypertensive medications reportedly improve cognition and decrease the risk of AD, while certain classes of anti-hypertensive drugs are associated with decreased AD-related pathology. We investigated the effects of hypertension and anti-hypertensive treatment on Aβ plaque load in postmortem frontal cortex in AD. Aβ load was significantly increased in hypertensive (n = 20) relative to normotensive cases (n = 62) and was also significantly higher in treated (n = 9) than untreated hypertensives (n = 11). We then looked into mechanisms by which hypertension and treatment might increase Aβ load, focusing on Aβ-synthesizing enzymes, β- and γ-secretase, and Aβ-degrading enzymes, angiotensin-converting enzyme (ACE), insulin-degrading enzyme (IDE) and neprilysin. ACE and IDE protein levels were significantly lower in hypertensive (n = 21) than normotensive cases (n = 64), perhaps translating to decreased Aβ catabolism in hypertensives. ACE level was significantly higher in treated (n = 9) than untreated hypertensives (n = 12), possibly reflecting feedback upregulation of the renin-angiotensin system. Prospective studies in larger cohorts stratified according to anti-hypertensive drug class are needed to confirm these initial findings and to elucidate the interactions between hypertension, anti-hypertensive treatments, and Aβ metabolism.

%B J Alzheimers Dis %V 50 %P 1191-203 %8 2016 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/26836178?dopt=Abstract %R 10.3233/JAD-150831 %0 Journal Article %J PLoS One %D 2010 %T Genetic evidence implicates the immune system and cholesterol metabolism in the aetiology of Alzheimer's disease. %A Jones, Lesley %A Holmans, Peter A %A Hamshere, Marian L %A Harold, Denise %A Moskvina, Valentina %A Ivanov, Dobril %A Pocklington, Andrew %A Abraham, Richard %A Hollingworth, Paul %A Sims, Rebecca %A Gerrish, Amy %A Pahwa, Jaspreet Singh %A Jones, Nicola %A Stretton, Alexandra %A Morgan, Angharad R %A Lovestone, Simon %A Powell, John %A Proitsi, Petroula %A Lupton, Michelle K %A Brayne, Carol %A Rubinsztein, David C %A Gill, Michael %A Lawlor, Brian %A Lynch, Aoibhinn %A Morgan, Kevin %A Brown, Kristelle S %A Passmore, Peter A %A Craig, David %A McGuinness, Bernadette %A Todd, Stephen %A Holmes, Clive %A Mann, David %A Smith, A David %A Love, Seth %A Kehoe, Patrick G %A Mead, Simon %A Fox, Nick %A Rossor, Martin %A Collinge, John %A Maier, Wolfgang %A Jessen, Frank %A Schürmann, Britta %A Heun, Reinhard %A Kölsch, Heike %A van den Bussche, Hendrik %A Heuser, Isabella %A Peters, Oliver %A Kornhuber, Johannes %A Wiltfang, Jens %A Dichgans, Martin %A Frölich, Lutz %A Hampel, Harald %A Hüll, Michael %A Rujescu, Dan %A Goate, Alison M %A Kauwe, John S K %A Cruchaga, Carlos %A Nowotny, Petra %A Morris, John C %A Mayo, Kevin %A Livingston, Gill %A Bass, Nicholas J %A Gurling, Hugh %A McQuillin, Andrew %A Gwilliam, Rhian %A Deloukas, Panos %A Al-Chalabi, Ammar %A Shaw, Christopher E %A Singleton, Andrew B %A Guerreiro, Rita %A Mühleisen, Thomas W %A Nöthen, Markus M %A Moebus, Susanne %A Jöckel, Karl-Heinz %A Klopp, Norman %A Wichmann, H-Erich %A Rüther, Eckhard %A Carrasquillo, Minerva M %A Pankratz, V Shane %A Younkin, Steven G %A Hardy, John %A O'Donovan, Michael C %A Owen, Michael J %A Williams, Julie %K Alzheimer Disease %K Apolipoproteins E %K Cholesterol %K Chromosome Mapping %K Genetic Predisposition to Disease %K Genome, Human %K Genome-Wide Association Study %K Humans %K Immune System %K Polymorphism, Single Nucleotide %X

BACKGROUND: Late Onset Alzheimer's disease (LOAD) is the leading cause of dementia. Recent large genome-wide association studies (GWAS) identified the first strongly supported LOAD susceptibility genes since the discovery of the involvement of APOE in the early 1990s. We have now exploited these GWAS datasets to uncover key LOAD pathophysiological processes.

METHODOLOGY: We applied a recently developed tool for mining GWAS data for biologically meaningful information to a LOAD GWAS dataset. The principal findings were then tested in an independent GWAS dataset.

PRINCIPAL FINDINGS: We found a significant overrepresentation of association signals in pathways related to cholesterol metabolism and the immune response in both of the two largest genome-wide association studies for LOAD.

SIGNIFICANCE: Processes related to cholesterol metabolism and the innate immune response have previously been implicated by pathological and epidemiological studies of Alzheimer's disease, but it has been unclear whether those findings reflected primary aetiological events or consequences of the disease process. Our independent evidence from two large studies now demonstrates that these processes are aetiologically relevant, and suggests that they may be suitable targets for novel and existing therapeutic approaches.

%B PLoS One %V 5 %P e13950 %8 2010 %G eng %N 11 %1 http://www.ncbi.nlm.nih.gov/pubmed/21085570?dopt=Abstract %R 10.1371/journal.pone.0013950