acid-phosphatase and Alzheimer-Disease

Prostatic Acid Phosphatase (PAP) is an enzyme that is produced primarily in the prostate and functions as a cell growth regulator and potential tumor suppressor. Understanding the genetic regulation of this enzyme is important because PAP plays an important role in prostate cancer and is expressed in other tissues such as the brain.. We tested association between 5.8 M SNPs and PAP levels in cerebrospinal fluid across 543 individuals in two datasets using linear regression. We then performed meta-analyses using METAL =with a significance threshold of p < 5 × 10(-8) and removed SNPs where the direction of the effect was different between the two datasets, identifying 289 candidate SNPs that affect PAP cerebrospinal fluid levels. We analyzed each of these SNPs individually and prioritized SNPs that had biologically meaningful functional annotations in wANNOVAR (e.g. non-synonymous, stop gain, 3' UTR, etc.) or had a RegulomeDB score less than 3.. Thirteen SNPs met our criteria, suggesting they are candidate causal alleles that underlie ACPP regulation and expression.. Given PAP's expression in the brain and its role as a cell-growth regulator and tumor suppressor, our results have important implications in brain health such as cancer and other brain diseases including neurodegenerative diseases (e.g., Alzheimer's disease and Parkinson's disease) and mental health (e.g., anxiety, depression, and schizophrenia).

Topics: Acid Phosphatase; Aged; Aged, 80 and over; Alleles; Alzheimer Disease; Brain; Brain Neoplasms; Gene Expression Regulation, Enzymologic; Gene Frequency; Genome-Wide Association Study; Genotype; Humans; Linear Models; Meta-Analysis as Topic; Middle Aged; Neurodegenerative Diseases; Polymorphism, Single Nucleotide; Risk Factors

Elevated levels of circulating cholesterol are extrinsic factors contributing to the pathogenesis of sporadic Alzheimer's disease (AD). We showed previously that rabbits fed a cholesterol-enriched diet exhibited blood-brain barrier (BBB) dysfunction, increased accumulation of apolipoprotein B (ApoB) in brain neurons, and endolysosomes in brain had disturbed structures and functions. These effects were linked to increased amyloid beta (Aβ) production, increased tau-pathology, and disrupted synaptic integrity. Because pathological changes to endolysosomes represent a very early event in sporadic AD, we determined here the extent to which ApoB-containing LDL cholesterol altered the structure and function of endolysosomes and contributed to the development of AD-like pathology in primary cultured neurons.. Cholesterol distribution and endolysosome morphology were determined histologically. Endolysosome pH was measured ratio-metrically with LysoSensor dye. Endolysosome enzyme activity was measured for acid phosphatase, cathepsins B and D, and beta-site APP cleaving enzyme 1 (BACE-1). AD-like pathologies, including increased production of Aβ, increased tau-pathology, and disrupted synaptic integrity were determined using ELISA, immunoblotting, and immunostaining techniques.. Treatment of neurons with ApoB-containing LDL cholesterol increased endolysosome accumulation of cholesterol, enlarged endolysosomes, and elevated endolysosome pH. In addition, ApoB-containing LDL cholesterol increased endolysosome accumulation of BACE-1, enhanced BACE-1 activity, increased Aβ levels, increased levels of phosphorylated tau, and decreased levels of synaptophysin.. Our findings suggest strongly that alterations in the structure and function of endolysosomes play a key role in the exhibition of pathological features of AD that result from neuronal exposure to ApoB-containing LDL cholesterol.

Topics: Acid Phosphatase; Alzheimer Disease; Amyloid beta-Peptides; Amyloid Precursor Protein Secretases; Animals; Apolipoproteins B; Aspartic Acid Endopeptidases; Cathepsin B; Cathepsin D; Cells, Cultured; Cholesterol, LDL; DNA Primers; Enzyme-Linked Immunosorbent Assay; Humans; Hydrogen-Ion Concentration; Immunoblotting; Immunohistochemistry; Lysosomes; Neurons; Rats; Real-Time Polymerase Chain Reaction; tau Proteins

We have previously reported that the activity of low molecular weight (LMW) acid phosphatase, which can remove tyrosine-linked phosphates of epidermal growth factor receptor, was significantly decreased in Alzheimer brains. In the present study, a specific antibody was prepared to analyze the protein level of this enzyme. Western blot analysis indicated that the level of LMW acid phosphatase protein was significantly reduced, whereas the activity of LMW acid phosphatase per enzyme molecule was not changed in Alzheimer brains. These results suggest that the reduction of LMW acid phosphatase activity in Alzheimer brains is due to its decreased protein level in Alzheimer's disease.

Topics: Acid Phosphatase; Aged; Alzheimer Disease; Antibodies; Humans; Immunoblotting; Molecular Weight

Ammonia is a natural lysosomotropic compound. Concentrations of ammonium acetate > 2 mM impaired the phagocytic activity of BV-2 cells, an immortalized microglial cell line, as was determined by the uptake of fluorescent latex microspheres of different sizes. In contrast, an increase in the uptake of fluorescent dextran was observed with the elevation in ammonium acetate concentrations. This indicates that ammonia affects phagocytotic and pinocytotic activities of BV-2 cells differently. Interferon-gamma- and polyinosinic-polycytidylic acid-stimulated secretion of IL1 alpha as well as LPS-stimulated secretion of IL6 decreased with an elevation in ammonium acetate concentrations. The constitutive secretion of IL1 alpha was not significantly affected by ammonium acetate. However, an increase in LPS-stimulated IL1 alpha secretion was observed at 10 mM and 20 mM ammonium acetate. High concentrations of ammonia affected the activity of lysosomal enzymes of the BV-2 cells. Acid phosphatase and alpha-glucosidase activities increased with the increase in ammonium acetate up to 20 mM. The activity of cathepsin D was increased at 5 mM, but decreased at higher ammonia concentrations. The effects of ammonia on microglial functions are discussed with respect to pathogenetic mechanisms of dementia of the Alzheimer type.

Topics: Acetates; Acid Phosphatase; Alzheimer Disease; Ammonia; Animals; beta-Glucosidase; Cathepsin D; Cell Line; Cytokines; Endocytosis; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Humans; Interleukin-1; Interleukin-6; Lysosomes; Mice; Microglia; Phagocytosis; Tumor Necrosis Factor-alpha

The origin of the various components of senile plaques in Alzheimer's disease (AD) continues to be a focus of intense research scrutiny. Lysosomal enzyme activity within the plaques is of particular interest because of its possible relevance to a presumed abnormal processing of precursor molecules that may lead to the formation of plaque amyloid. Histochemical evidence of acid phosphatase (ACP), a lysosomal hydrolase, activity in senile plaques has been documented long before many of the current biochemical data regarding plaque pathogenesis became available. Recent evidence suggests the presence of neuronal membrane abnormalities that may allow "leakage" of some intracellular molecules, including enzymes, into the perineuronal environment and from there, possibly, to the cerebrospinal fluid (CSF). In the course of investigating this hypothesis, we decided to readdress the issue of ACP activity in AD by assaying the enzyme both in brain tissue sections as well as in CSF samples from neuropathologically confirmed cases of AD and from normal control subjects. Brain frozen sections from five cases with AD and five control subjects were histochemically stained for ACP using the alpha-naphthylphosphate hydrolysis method. Frozen CSF samples from 15 cases with AD and 19 control subjects were assayed for ACP activity using the thymolphthalein monophosphate hydrolysis method. In all cases studied, CSFs were cytologically unremarkable. Neurons in normal and AD brains were strongly positive for ACP. In AD, numerous senile plaques showed strong ACP activity with both granular and diffuse patterns. The CSFs from six of 15 AD cases (40%) showed ACP activity with values ranging from 0.04 to 0.4 U/L. No ACP activity was detected in any of the 19 control CSFs analyzed. The exact source of ACP in senile plaques and CSF of patients with AD cannot be established based on these data alone but the ACP may have originated from neurons with oxidative stress or oxygen free radical-mediated membrane damage. The data encourage further investigation of this hypothesis.

Topics: Acid Phosphatase; Aged; Aged, 80 and over; Alzheimer Disease; Brain; Humans

Recent studies in Alzheimer brains have shown aberrant protein phosphorylation, suggesting an alteration in protein kinases and/or phosphoprotein phosphatases. In the present study, the activity of acid phosphatase was investigated in samples prepared from postmortem normal human and Alzheimer brains. p-Nitrophenyl phosphate, a nonprotein phosphoester, was used as a substrate for acid phosphatase. The separation profile on Sephadex G-100 gel filtration chromatography revealed that two major forms of high-molecular-weight and low-molecular-weight acid phosphatase were present in the crude extracts of both rat and human brains. Another class of zinc ion (Zn2+)-dependent acid p-nitrophenyl phosphatase was also detected in rat and human brains. In Alzheimer brains, the low-molecular-weight acid phosphatase activity was significantly decreased compared to that in control brains; however, the high-molecular-weight and Zn(2+)-dependent acid phosphatase activity in control and Alzheimer brains was not different. These results suggest that reduced activity of the low-molecular-weight acid phosphatase, which possesses phosphotyrosine protein phosphatase activity, might be linked to aberrant protein tyrosine phosphorylation found in Alzheimer brains.

Topics: Acid Phosphatase; Aged; Aged, 80 and over; Alzheimer Disease; Analysis of Variance; Animals; Brain; Chromatography, Gel; Enzyme Stability; Hippocampus; Humans; Isoenzymes; Kinetics; Middle Aged; Molecular Weight; Postmortem Changes; Rats; Reference Values; Temporal Lobe

The authors have previously shown that amyloid precursor protein (APP) accumulates in neurites present in senile plaques of Alzheimer's disease (AD). In this ultrastructural immunocytochemical study, we describe the subcellular site of APP accumulation. Vibratome sections of glutaraldehyde-paraformaldehyde fixed hippocampi from five cases of AD were pretreated with methanol and immunostained with an antibody raised against recombinant APP 770 by using either indirect immunogold or peroxidase methods. Immunolabeling was localized in cell processes filled with amorphous, irregular-shaped materials, which were identified as dense bodies deformed by postmortem autolysis and methanol treatment, as well as multilamellar membranous bodies. Identification of these bodies was obtained with comparative ultrastructural examination of biopsy and autopsy tissue fixed with and without methanol treatment. These electron-dense organellae were positive for the lysosomal marker, acid phosphatase. At light microscopy, acid phosphatase and APP colocalized to the same cell processes in senile plaques. Many of those cell processes contained abnormal straight or paired helical filaments supporting their neuritic nature. These results suggest that APP accumulates in the lysosomal system of the dystrophic neurites present in senile plaques and are consistent with a neuronal origin of the APP forming the amyloid in senile plaques.

Topics: Acid Phosphatase; Alzheimer Disease; Amyloid beta-Protein Precursor; Hippocampus; Humans; Immunoenzyme Techniques; Immunohistochemistry; Methanol; Microscopy, Electron; Neurites; Postmortem Changes; Subcellular Fractions; tau Proteins

Alz-50 is a monoclonal antibody that detects antigens enriched in the brain tissue of Alzheimer's disease (AD) patients. Although Alz-50 recognizes tau, an identified integral constituent of the AD paired helical filament (PHF), the exact nature of the antigenic site is unknown. An immunoblot analysis demonstrated that the antigenic sites to Alz-50 are diminished by acid phosphatase treatment. Consistent with this finding, Alz-50 antigens were more concentrated in brain homogenates prepared with phosphatase inhibitors. The epitope in tau with which Alz-50 reacts is located in the carboxy terminus within a 14-amino acid region from just beyond the microtubule-binding repeats to the carboxy terminus. An isolated carboxy-terminal chymotryptic peptide from bovine brain tau reactive with Alz-50 was analyzed by fast-atom-bombardment mass spectroscopy (FAB-MS) and was found to be present as both a monophosphopeptide and a nonphosphorylated peptide. The immunohistological analysis has demonstrated that Alz-50 staining of neurofibrillary tangles (NFTs) is sensitive to acid phosphatase but not to alkaline phosphatase. Furthermore, Alz-50 staining of NFTs was effectively adsorbed by a high concentration of phosphoserine but not by serine or phosphothreonine. These results strongly suggest that Alz-50 recognizes a phosphorylated epitope in the carboxy terminus of tau which has not been previously detected by using alkaline phosphatase. The strong Alz-50 staining in AD samples may represent another association between a phosphorylation state and neurofibrillary lesions. As a marker of the inchoate tangle-bearing neuron, the characterization of the Alz-50 epitope in tau offers a partial molecular basis for the modifications that contribute to the assembly of PHFs.

Topics: Acid Phosphatase; Alzheimer Disease; Amino Acid Sequence; Antibodies, Monoclonal; Blotting, Western; Brain; Chromatography, High Pressure Liquid; Epitopes; Humans; Immunohistochemistry; Mass Spectrometry; Microtubule-Associated Proteins; Molecular Sequence Data; Molecular Weight; Neurofibrils; Phosphorylation; Phosphoserine; tau Proteins

Rabbits were injected intracerebrally with aluminum salt leading to experimental neurofibrillary change formation as a model of Alzheimer neurofibrillary change. Eleven days after the injection, the brain tissues were excised from the cortex, hippocampus, and cervical region of spinal cord. Five lysosomal enzymes (cathepsin D, beta-glucuronidase, acid phosphatase, acid DNase, alkaline DNase) were assayed and compared with the control. Cathepsin D, acid DNase and beta-glucuronidase activities increased significantly in all 3 areas of aluminum-injected brain. On the other hand, acid phosphatase and alkaline DNase activities remained at the same level. The results showed the lysosomal enzymes did not change in parallel after aluminum administration, suggesting a role of the increased enzymes in the brain with neurofibrillary changes.

Topics: Acid Phosphatase; Aluminum; Alzheimer Disease; Animals; Brain; Cathepsin D; Deoxyribonucleases; Glucuronidase; Hydrolases; Lysosomes; Neurofibrils; Rabbits

Using immunohistochemical and enzyme histochemical methods, we have investigated the presence of mononuclear phagocytic cells around senile plaques in six brains from patients with senile dementia of the Alzheimer type (SDAT). It is generally supposed that reactive microglial cells are involved in amyloid formation "as representatives of the reticuloendothelial system in the brain." We used different monoclonal antibodies directed against cells of the mononuclear phagocyte lineage, antibodies against the macrophage markers alpha 1-antichymotrypsin and lysozyme, and the lectin WGA, in addition to enzyme histochemical staining for nonspecific esterase and acid phosphatase. It was concluded that no macrophages of the mononuclear phagocyte lineage are involved in plaque formation. The role of glial cells in amyloid formation is discussed.

Topics: Acid Phosphatase; Aged; Alzheimer Disease; Brain; Glial Fibrillary Acidic Protein; Humans; Immunoenzyme Techniques; Neurons

The water-soluble proteins of the cerebral gray matter and some enzyme systems (cholinesterase, acetylcholinesterase, lactate dehydrogenase, malate dehydrogenase, acid phosphatase) were studied in 9 autopsy cases of Alzheimer's presenile or senile dementia, 1 case of Pick's disease and 1 case of cerebral arteriosclerosis. The proteins and enzyme patterns were visualized on polyacrylamide gradient gels after electrophoresis. In all patients studied, the profiles of cerebral gray-matter proteins were normal. In the patients with advanced dementia, the enzyme patterns usually were abnormal. Particularly in Alzheimer's disease, the activity of malate dehydrogenase was markedly increased.

Topics: Acetylcholinesterase; Acid Phosphatase; Aged; Alzheimer Disease; Brain; Brain Chemistry; Cholinesterases; Dementia; Female; Humans; Intracranial Arteriosclerosis; L-Lactate Dehydrogenase; Malate Dehydrogenase; Male; Nerve Tissue Proteins