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1.  Stereologic estimates of total spinophilin-immunoreactive spine number in area 9 and the CA1 field: relationship with the progression of Alzheimer’s disease 
Neurobiology of aging  2007;29(9):1296-1307.
The loss of presynaptic markers is thought to represent a strong pathologic correlate of cognitive decline in Alzheimer’s disease (AD). Spinophilin is a postsynaptic marker mainly located to the heads of dendritic spines. We assessed total numbers of spinophilin-immunoreactive puncta in the CA1 and CA3 fields of hippocampus and area 9 in 18 elderly individuals with various degrees of cognitive decline. The decrease in spinophilin-immunoreactivity was significantly related to both Braak neurofibrillary tangle (NFT) staging and clinical severity but not Aβ deposition staging. The total number of spinophilin-immunoreactive puncta in CA1 field and area 9 were significantly related to MMSE scores and predicted 23.5% and 61.9% of its variability. The relationship between total number of spinophilin-immunoreactive puncta in CA1 field and MMSE scores did not persist when adjusting for Braak NFT staging. In contrast, the total number of spinophilin-immunoreactive puncta in area 9 was still significantly related to the cognitive outcome explaining an extra 9.6% of MMSE and 25.6% of the Clinical Dementia Rating scores variability. Our data suggest that neocortical dendritic spine loss is an independent parameter to consider in AD clinicopathologic correlations.
doi:10.1016/j.neurobiolaging.2007.03.007
PMCID: PMC2569870  PMID: 17420070
Alzheimer’s disease; cognition; synapses; tangles
2.  Association of ApoE and LRP mRNA levels with dementia and AD neuropathology 
Neurobiology of Aging  2011;33(3):628.e1-628.e14.
Inheritance of the ε4 allele of ApoE is the only confirmed and consistently replicated risk factor for late onset AD. ApoE is also a key ligand for LRP, a major neuronal LDL receptor. Despite the considerable converging evidence that implicates ApoE and LRP in the pathogenesis of AD, the precise mechanism by which ApoE and LRP modulate the risk for AD remains elusive. Moreover, studies investigating expression of ApoE and LRP in AD brain have reported variable and contradictory results. To overcome these inconsistencies, we studied the mRNA expression of ApoE and LRP in the postmortem brain of persons who died at different stages of dementia and AD-associated neuropathology relative to controls by qPCR and Western blotting. Clinical dementia rating scores were used as a measure of dementia severity, whereas, Braak neuropathological staging and neuritic plaque density were used as indices of the neuropathological progression of AD. ApoE and LRP mRNA expression was significantly elevated in the postmortem inferior temporal gyrus (area 20) and the hippocampus from individuals with dementia compared to those with intact cognition. In addition to their strong association with the progression of cognitive dysfunction, LRP and ApoE mRNA levels were also positively correlated with increasing neuropathological hallmarks of AD. Additionally, Western blot analysis of ApoE protein expression in the hippocampus showed that the differential expression observed at the transcriptional level is also reflected at the protein level. Given the critical role played by LRP and ApoE in Aβ and cholesterol trafficking, increased expression of LRP and ApoE may not only disrupt cholesterol homeostasis but may also contribute to some of the neurobiological features of AD, including plaque deposition.
doi:10.1016/j.neurobiolaging.2011.04.010
PMCID: PMC3234309  PMID: 21676498
3.  Increased expression of cholesterol transporter ABCA1 is highly correlated with severity of dementia in AD hippocampus 
Brain research  2010;1318C:167-177.
To gain insight into ATP-binding cassette transporter A1 (ABCA1) function and its potential role in AD pathology, we analyzed the expression of the cholesterol transporter ABCA1 in postmortem hippocampus from persons at different stages of dementia and AD associated neuropathology relative to cognitively intact normal donors by quantitative polymerase chain reaction (qPCR) and Western blot. In this study clinical dementia rating (CDR) scores were used as a measure of dementia severity, whereas, Braak neuropathological staging and neuritic plaque density were used as an index of the neuropathological progression of AD. Correlation analysis showed that ABCA1 mRNA expression was significantly elevated at the earliest recognizable stage of dementia compared to persons with intact cognition. ABCA1 mRNA was also positively correlated with Braak neuropathological stages and neuritic plaque density counts. Additionally, ABCA1 mRNA levels showed robust correlation with dementia severity even after controlling for the confounding contribution of accompanying neuropathological parameters to ABCA1 mRNA expression. Western blot analyses showed that the differential expression observed at the transcriptional level is also reflected at the protein level. Thus, our study provides transcriptional and translational evidence that the expression of ABCA1, a key modulator of cholesterol transport across the plasma membrane, is dysregulated in the AD brain and that this dysregulation is associated with increasing severity of AD, whether measured functionally as dementia severity or neuropathologically as increased neuritic plaque and neurofibrillary tangle density.
doi:10.1016/j.brainres.2010.01.006
PMCID: PMC2826590  PMID: 20079340
4.  Increased expression of RXRα in dementia: an early harbinger for the cholesterol dyshomeostasis? 
Background
Cholesterol content of cerebral membranes is tightly regulated by elaborate mechanisms that balance the level of cholesterol synthesis, uptake and efflux. Among the conventional regulatory elements, a recent research focus has been nuclear receptors, a superfamily of ligand-activated transcription factors providing an indispensable regulatory framework in controlling cholesterol metabolism pathway genes. The mechanism of transcriptional regulation by nuclear receptors such as LXRs involves formation of heterodimers with RXRs. LXR/RXR functions as a sensor of cellular cholesterol concentration and mediates cholesterol efflux by inducing the transcription of key cholesterol shuffling vehicles namely, ATP-binding cassette transporter A1 (ABCA1) and ApoE.
Results
In the absence of quantitative data from humans, the relevance of expression of nuclear receptors and their involvement in cerebral cholesterol homeostasis has remained elusive. In this work, new evidence is provided from direct analysis of human postmortem brain gene and protein expression suggesting that RXRα, a key regulator of cholesterol metabolism is differentially expressed in individuals with dementia. Importantly, RXRα expression showed strong association with ABCA1 and ApoE gene expression, particularly in AD vulnerable regions.
Conclusions
These findings suggest that LXR/RXR-induced upregulation of ABCA1 and ApoE levels may be the molecular determinants of cholesterol dyshomeostasis and of the accompanying dementia observed in AD.
doi:10.1186/1750-1326-5-36
PMCID: PMC2949865  PMID: 20843353

Results 1-4 (4)