The fact that PBT2 is an 8-OHQ analog does give it anti-fungal and antibacterial properties.
There was some talk this year about immune involvement in AD. Especially the comment by John Hardy where he said the two take aways from this year's conference were 1- Tanzi's innovative and groundbreaking model and 2-immune involvement in AD. Below is just a sampling of some of the 60 or so immune-related presentations.
Cellular Modeling of Inflammation Relevant to Alzheimer's Disease: Molecular and Cytokine Analysis of Host Responses Following Chlamydial Infection of Human THP-1 Monocytes
Abstract:
Christine J Hammond, MS;Jonathan M Anzmann, MS;Abhi P Jain, DPT, MEd;Susan T Hingley, PhD and Brian J Balin, PhD, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, USA
Background: Our previous investigations have identified an association between brain infection with Chlamydia pneumoniae (Cpn) and late-onset Alzheimer disease (AD). We have demonstrated that Cpn is detectable in AD brain tissues in a variety of cell types including neurons, glia, endothelial cells, and perivascular macrophages. In addition, Cpn has been identified within monocytes from human blood samples from geriatric patients who have demonstrated cognitive change. As we have seen Cpn infection in both peripheral cells and in autopsy brain tissues, this study sought to further understand the initiation of neuroinflammation by using our in vitro infection model. Methods: Human THP-1 monocytes were infected with Cpn to establish acute (24hr) to chronic/persistent (120hr) infections. Host responses following infection were analyzed using ELISA for inflammatory cytokines. Molecular analysis consisted of evaluating host gene transcript changes using commercial human neuroinflammation and inflammasome real time PCR Arrays and specific changes using IDO1, IDO2, CCL2, AIM2 and IL-1beta primer sets. The infection was analyzed using immunofluorescence microscopy and real time PCR for Chlamydial gene transcripts. Results: Immunofluorescence microscopy revealed Cpn infection of the monocytes at all times post-infection with at least 50% of cells infected at any time point. Inflammatory cytokines for IL-1 beta and IL-18 were increased in infected THP-1 monocytes when compared to uninfected THP-1. Real time PCR analysis revealed upregulation of gene transcripts for numerous host inflammatory and inflammasome genes, many of which have been previously correlated to AD such as CCL2, IL-1beta, IL-6, Caspases, and NFKB1. These transcript changes were consistent with cytokine detection. Conclusions: Infection of THP-1 monocytes with Chlamydia pneumoniae results in unregulated host gene transcripts and increased cytokine production similar to those seen in sporadic late-onset Alzheimer disease samples. These findings support the AD infection hypothesis whereby infection can be a prominent initiating component in AD neurodegeneration.
Chlamydia Pneumoniae-infected Astrocytes Alter Their Expression of ADAM10, BACE1, and Presenilin-1 Proteases
Abstract:
Zein Al-Atrache;Ahmad Cader, MS and Denah M Appelt, PhD, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, USA
Background: Utilizing β-amyloid precursor protein (βAPP) as a substrate, α-, β-, and γ-secretases are responsible for sequential cleavage events leading to the formation of β-amyloid, the classic pathologic hallmark of Alzheimer’s Disease. Members of this class of proteases also catalyze the activation of numerous other membrane-localized proteins implicated in cell growth and neuroinflammation such as NOTCH and the Interleukin/TNF-receptor family, respectively. This investigation addresses if an in vitro Chlamydia pneumoniae infection of human astrocytes affects the processing of βAPP through modifying the protein expression of the following βAPP processing proteases: A Disintegrin and Metalloproteinase-10 (ADAM10), βAPP cleaving enzyme-1 (BACE1), and presenilin-1 (PSEN1). Methods: Human astrocytoma cells (CCF-STTG1) were infected in vitro with Chlamydia pneumoniae strain AR39 (MOI=1). At 6-72 hours post infection, protein level of β-amyloid, ADAM10, BACE1, and presenilin-1 N-terminal fragment (NTF) relative to uninfected controls were detected by immunofluorescence and quantified by western blot analysis. Results: Cytoplasmic labeling of Aβ1-42 was increased in infected cells relative to that of uninfected cells. Membrane-localized labeling of BACE1 and cytoplasmic labeling of PSEN1 NTF was also enhanced at earlier (6 hrs.) and later (48/72 hrs.) time points post infection relative to that of uninfected astrocytes. Increases in quantified BACE1 and PSEN1, but not ADAM10, followed a similar temporal increase most notable at 48 hrs. post infection. Conclusions: These data indicate that infection of human astrocytes with Chlamydia pneumoniae strain AR39 promotes the processing of βAPP characteristic of Alzheimer’s Disease through enhancing BACE1 and PSEN1, but not ADAM10, protein levels. Increases in active secretase protein may coincide with the 24-48 hr. lifecycle of Chlamydial intracellular growth and replication and the consequent astrocytic inflammatory response.
Integrative Analysis of GWAS Summary Data and Functional Annotations Highlights Signal Enrichment in Immune-Related DNA Elements for Late-Onset Alzheimer’s Disease
Abstract:
Qiongshi Lu1;Shubhabrata Mukherjee, PhD2;Paul K Crane, MD, MPH2 and Hongyu Zhao, PhD1, (1)Yale University, New Haven, CT, USA, (2)University of Washington, Seattle, WA, USA
Backgroundespite the success of late-onset Alzheimer’s disease (LOAD) genome-wide association studies (GWAS), our understanding of its genetic architecture and disease etiology is still far from complete. Recent advancements in integrative genomic functional annotations, coupled with statistical techniques to partition heritability by these annotations, have provided insights to human complex diseases. Here we apply state-of-the-art methods to identify tissue- and cell type-specific functional DNA elements enriched for LOAD GWAS signals. Methods:We analyzed Stage I genome-wide meta-analysis summary statistics from the International Genomics of Alzheimer’s Project (IGAP) using LD score regression and GenoSkyline tissue-specific functional annotations. We defined enrichment as the ratio between the percentage of heritability explained by variants in each annotated category and the percentage of variants covered by that category. We developed cell-type-specific annotations for all 23 immune cells in the Roadmap Epigenomics Project through integrative analysis of epigenomic marks from ChIP-seq data. We applied LD score regression to these annotations to identify relevant cell types whose functional regions are relatively enriched for LOAD genetic associations. Results: Variants located in blood-specific functional regions, which account for 8.4% of the variants in the IGAP data, could explain 81.6% of LOAD heritability (enrichment=9.6; p-value=9.6×10-7). The signal enrichment for blood-specific elements was substantially stronger than the enrichment for brain-specific elements (p-value=2.0×10-2) and for other tissue types. On the cell level, we observed strong enrichment in many cells, including primary neutrophils from peripheral blood (p-value=7.9×10-5), primary hematopoietic stem cells from males or females mobilized with G-CSF (p-values=3.8×10-4 and 4.2×10-4), primary B cells from peripheral blood (p-value=2.2×10-3), and primary monocytes from peripheral blood (p-value=4.4×10-3). Analysis based on refined annotation categories further revealed that the enrichment in primary neutrophils could be explained by shared functional elements with hematopoietic stem cells. T cells showed weaker signal enrichment compared with other immune cells. Conclusions: Tissue-specific enrichment analyses of IGAP Stage I data identified strong signal enrichment in blood, suggesting a crucial role for the immune system in LOAD etiology. Our findings provide additional support to the notion that microglial biology may be critically relevant in LOAD etiology, and suggest a previously unsuspected role for neutrophils.
PBT Price at posting:
9.9¢ Sentiment: Buy Disclosure: Held
espite the success of late-onset Alzheimer’s disease (LOAD) genome-wide association studies (GWAS), our understanding of its genetic architecture and disease etiology is still far from complete. Recent advancements in integrative genomic functional annotations, coupled with statistical techniques to partition heritability by these annotations, have provided insights to human complex diseases. Here we apply state-of-the-art methods to identify tissue- and cell type-specific functional DNA elements enriched for LOAD GWAS signals. Methods:We analyzed Stage I genome-wide meta-analysis summary statistics from the International Genomics of Alzheimer’s Project (IGAP) using LD score regression and GenoSkyline tissue-specific functional annotations. We defined enrichment as the ratio between the percentage of heritability explained by variants in each annotated category and the percentage of variants covered by that category. We developed cell-type-specific annotations for all 23 immune cells in the Roadmap Epigenomics Project through integrative analysis of epigenomic marks from ChIP-seq data. We applied LD score regression to these annotations to identify relevant cell types whose functional regions are relatively enriched for LOAD genetic associations. Results: Variants located in blood-specific functional regions, which account for 8.4% of the variants in the IGAP data, could explain 81.6% of LOAD heritability (enrichment=9.6; p-value=9.6×10-7). The signal enrichment for blood-specific elements was substantially stronger than the enrichment for brain-specific elements (p-value=2.0×10-2) and for other tissue types. On the cell level, we observed strong enrichment in many cells, including primary neutrophils from peripheral blood (p-value=7.9×10-5), primary hematopoietic stem cells from males or females mobilized with G-CSF (p-values=3.8×10-4 and 4.2×10-4), primary B cells from peripheral blood (p-value=2.2×10-3), and primary monocytes from peripheral blood (p-value=4.4×10-3). Analysis based on refined annotation categories further revealed that the enrichment in primary neutrophils could be explained by shared functional elements with hematopoietic stem cells. T cells showed weaker signal enrichment compared with other immune cells. Conclusions: Tissue-specific enrichment analyses of IGAP Stage I data identified strong signal enrichment in blood, suggesting a crucial role for the immune system in LOAD etiology. Our findings provide additional support to the notion that microglial biology may be critically relevant in LOAD etiology, and suggest a previously unsuspected role for neutrophils.
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