Structural Properties of Inverted Hexagonal Phase: A Hybrid Computational and Experimental Approach

Inverted/reverse hexagonal (H_II) phases are of special interest in several fields of research, including nanomedicine. We used molecular dynamics (MD) simulation to study H_II systems composed of dioleoylphosphatidylethanolamine (DOPE) and palmitoyloleoylphosphatidylethanolamine (POPE) at several hydration levels and temperatures. The effect of the hydration level on several H_II structural parameters, including deuterium order parameters, was investigated. We further used MD simulations to estimate the maximum hydrations of DOPE and POPE H_II lattices at several given temperatures. Finally, the effect of acyl chain unsaturation degree on the H_II structure was studied via comparing the DOPE with POPE H_II systems. In addition to MD simulations, we used deuterium nuclear magnetic resonance (²H NMR) and small-angle X-ray scattering (SAXS) experiments to measure the DOPE acyl chain order parameters, lattice plane distances, and the water core radius in H_II phase DOPE samples at several temperatures in the presence of excess water. Structural parameters calculated from MD simulations are in excellent agreement with the experimental data. Dehydration decreases the radius of the water core. An increase in hydration level slightly increased the deuterium order parameter of lipids acyl chains, whereas an increase in temperature decreased it. Lipid cylinders undulated along the cylinder axis as a function of hydration level. The maximum hydration levels of PE H_II phases at different temperatures were successfully predicted by MD simulations based on a single experimental measurement for the lattice plane distance in the presence of excess water. An increase in temperature decreases the maximum hydration and consequently the radius of the water core and lattice plane distances. Finally, DOPE formed H_II structures with a higher curvature compared to POPE, as expected. We propose a general protocol for constructing computational H_II systems that correspond to the experimental systems. This protocol could be used to study H_II systems composed of molecules other than the PE systems used here and to improve and validate force field parameters by using the target data in the H_II phase.

Ionizable amino lipid interactions with POPC: implications for lipid nanoparticle function

Lipid nanoparticles (LNPs) composed of ionizable cationic lipids are currently the leading systems for siRNA delivery in liver disease, with the major limitation of low siRNA release efficacy into the cytoplasm. Ionizable cationic lipids are known to be of critical importance in LNP structure and stability, siRNA entrapment, and endosomal disruption. However, their distribution inside the LNPs and their exact role in cytoplasmic delivery remain unclear. A recent study [Kulkarni et al., On the formation and morphology of lipid nanoparticles containing ionizable cationic lipids and siRNA, ACS Nano, 2018, 12(5), 4787-4795] on LNP-siRNA systems containing the ionizable lipid DLin-KC2-DMA (also known as KC2 with an apparent pKa of ca. 6.7) suggested that neutral KC2 segregates from other components and forms an amorphous oil droplet in the core of LNPs. In this paper, we present evidence supporting the model proposed by Kulkarni et al. We studied KC2 segregation in the presence of POPC using molecular dynamics simulation, deuterium NMR, SAXS, and cryo-TEM experiments, and found that neutral KC2 has a high tendency to separate from POPC dispersions. KC2 confinement, upon raising the pH during the formulation process, could result in rearrangement of the internal structure of LNPs. As interactions between cationic KC2 and anionic endosomal lipids are thought to be a key factor in cargo release, KC2 confinement inside the LNP may be responsible for the observed low release efficacy.

AGRICULTURAL BEST MANAGEMENT PRACTICE SENSITIVITY TO CHANGING AIR TEMPERATURE AND PRECIPITATION

Agricultural best management practices (BMPs) reduce non-point source pollution from cropland. Goals for BMP adoption and expected pollutant load reductions are often specified in water quality management plans to protect and restore waterbodies; however, estimates of needed load reductions and pollutant removal performance of BMPs are generally based on historic climate. Increasing air temperatures and changes in precipitation patterns and intensity are anticipated throughout the U.S. over the 21st century. The effects of such changes on agricultural pollutant loads have been addressed by several authors, but how these changes will affect the performance of widely promoted BMPs has received limited attention. We use the Soil and Water Assessment Tool (SWAT) to investigate potential changes in the effectiveness of conservation tillage, no-till, vegetated filter strips, grassed waterways, nutrient management, winter cover crops, and drainage water management practices under potential future temperature and precipitation patterns. We simulate two agricultural watersheds in the Minnesota Corn Belt and the Georgia Coastal Plain with different hydro-climatic settings, under recent conditions (1950-2005) and multiple potential future mid-century (2030-2059) and late-century (2070-2099) climate scenarios. Results suggest future increases in agricultural source loads of sediment, nitrogen and phosphorous. Most BMPs continue to reduce loads, but removal efficiencies generally decline due to more intense runoff events, biological responses to changes in soil moisture and temperature, and exacerbated upland loading. The coupled effects of higher upland loading and reduced BMP efficiencies suggest that wider adoption, resizing, and/or combining practices may be needed in the future to meet water quality goals for agricultural lands.

Abstract 1483: Alteration of miR-186 expression modifies inflammatory markers in normal epithelial and prostate cancer cell models

Dysregulation of miRNAs and chronic inflammation are strongly implicated in the development of various malignancies, including prostate cancer (PCa). Previously, our lab identified several inflammatory and immune response sequence variants in CCL5 and CCR5 significantly modified PCa risk. Recently, we propose an oncogenic role for miR-186-5p based on its up-regulation in serum from PCa patients and metastatic PCa cell lines. Moreover, miR-186-5p inhibition reduced proliferation, anchorage independent growth and invasion in metastatic PC cells (PC3, MDA-PCA-2b). We hypothesize dysregulation of inflammatory and immune response markers may enhance immune surveillance leading to a reduced aggressive tumor phenotype. Following modulations in miRNA-186 levels in normal prostate epithelial (RWPE1) and metastatic PCa (PC3) cell lines, we evaluated alterations in mRNA expression using micro-array analysis. Ectopic expression of miRNA-186 in the RWPE1 resulted in a 1.3-2.6-fold down-regulation in TLR2, IRAK2, CCL20, IL1RAP, IL1RAP, IL15, and IL17RD (FDR p-value ≥7.8x10-06). Whereas, inhibition of miR-186 in PC3 cells corresponded with a 1.4-fold up-regulation of IL18R1 (p=0.0095). Notably, these inflammatory markers are involved in cell invasion (TLR2), apoptosis (IL17RD), tumorigenesis (TLR2, IRAK2) and autoimmune diseases (CCL20). Validation of these targets is underway using qRT-PCR, western blots and luciferase reporter assays. We will assess the mechanism by which these miR-186 targets suppress aggressive cancer behavior using knock-out and knock-in cell and ultimately animal models. Future studies may identify inflammatory targets that may guide immune therapies for the effective treatment of aggressive prostate cancer.

Citation Format: Suman Suman, Dominique Z. Jones-Reed, M. L. Schmidt, Geoffrey J. Clark, Carolyn Klinge, Shirish Barve, Kevin S. Kimbro, La Creis R. Kidd. Alteration of miR-186 expression modifies inflammatory markers in normal epithelial and prostate cancer cell models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1483. doi:10.1158/1538-7445.AM2017-1483

Gas-phase fragmentations of N-methylimidazolidin-4-one organocatalysts

N-methylimidazolidin-4-one organocatalysts were studied in the gas phase. Protonated and sodium-cationized (sodiated) molecules are conveniently accessible by electrospray mass spectrometry. Protonation enables three different closed-shell paths of ring cleavage leading to iminium ions. The fragmentation pattern is largely unaffected by exocyclic substituents and thus is valuable to characterize the substance type as N-methylimidazolidin-4-ones. Sodiated species show a distinctly different fragmentation that is less useful for characterization purposes: apart from signal loss due to dissociation of Na⁺ , the observation of benzyl radical loss is by far predominant. Only in absence of a benzyl substituent, an analogue of the third ring cleavage (loss of [C₂ H₅ NO]) is observed. Copyright © 2017 John Wiley & Sons, Ltd.

A porcine model system of BRCA1 driven breast cancer

BRCA1 is a breast and ovarian tumor suppressor. Hereditary mutations in BRCA1 result in a predisposition to breast cancer, and BRCA1 expression is down-regulated in ~30% of sporadic cases. The function of BRCA1 remains poorly understood, but it appears to play an important role in DNA repair and the maintenance of genetic stability. Mouse models of BRCA1 deficiency have been developed in an attempt to understand the role of the gene in vivo. However, the subtle nature of BRCA1 function and the well-known discrepancies between human and murine breast cancer biology and genetics may limit the utility of mouse systems in defining the function of BRCA1 in cancer and validating the development of novel therapeutics for breast cancer. In contrast to mice, pig biological systems, and cancer genetics appear to more closely resemble their human counterparts. To determine if BRCA1 inactivation in pig cells promotes their transformation and may serve as a model for the human disease, we developed an immortalized porcine breast cell line and stably inactivated BRCA1 using miRNA. The cell line developed characteristics of breast cancer stem cells and exhibited a transformed phenotype. These results validate the concept of using pigs as a model to study BRCA1 defects in breast cancer and establish the first porcine breast tumor cell line.

Abstract 3085: MicroRNA-186 inhibition alters cell proliferation and colony formation in prostate cancer

MicroRNAs (miRs), key regulators of cancer-related genes, are dysregulated in many solid tumors, including prostate cancer. However, the role of miR-186 in prostate cancer (PCA) requires further elucidation. Previously, we observed mature miR-186-5p was significantly up-regulated in the serum collected from PCA patients (n = 15) diagnosed with aggressive PCA (stage III/IV) disease compared to disease-free men (n = 5). In addition, miR-186 expression was significantly up-regulated in metastatic PCA cells (PC3) compared to a normal prostate epithelial cell line (RWPE1). Putative and predicted miR-186 gene targets in various cancers include pro-apoptotic and tumor suppression-related genes (e.g., P2×7, FOXO1, AKAP12). We hypothesized that miR-186 inhibition will reduce the aggressive PCA phenotype.

To test this hypothesis, PC3 cells were transiently transfected with miR-186 inhibitor and scramble control for 24hrs. Cell viability and colony formation of transfected cells were evaluated via the ATPlite Luminescence assay and soft agar assay. We also evaluated expression profiles of predicted miR-186 gene targets in PCA cell lines and transiently transfected PC3 cells using qRT-PCR.

Transient inhibition of miR-186 repressed cellular proliferation and colony formation by 48-58% in 72-96hrs and 30% after 21 days, respectively. We observed a 1.6-2.24 fold up-regulation in ROCK1 gene expression in PC3 cells treated with miR-186 inhibitor. However, additional studies are needed to assess whether stable inhibition of miR-186 will increase PCA invasiveness by up-regulating ROCK1 using in vitro assays and murine models. Moreover, predicted miR-186 gene targets require validation using qRT-PCR, western blots and luciferase reporter assays. Such efforts may lead to the identification of novel biomarkers to improve diagnostic, prognostic and clinical management strategies.

Citation Format: Dominique Zilpha Jones, Katharine R. Hobbing, M. L. Schmidt, Geoffrey J. Clark, LaCreis R. Kidd. MicroRNA-186 inhibition alters cell proliferation and colony formation in prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3085. doi:10.1158/1538-7445.AM2015-3085

Significance of tumor biology compared to metastatic pattern (INSS 4 versus 4s) and age for prognosis of neuroblastoma less than 18 months of age

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Background: Neuroblastoma is a heterogeneous disease with variability in outcome among different risk groups. Historically, INSS stage 4s neuroblastoma (age less than 12 months, stage 1 or 2 primary tumor with metastases limited to liver, skin and bone marrow) has a more favorable outcome than infant stage 4 disease. The aim was to determine if metastatic pattern (4 vs 4s) predicted favorable prognosis in infants < 12 months or in toddlers aged 12–18 months when stratifying by biology. Methods: Outcome was analyzed by log rank tests and Cox models for 656 infants with stage 4s neuroblastoma and 1,019 stage 4 patients < 18 months of age in the International Neuroblastoma Risk Group database (n=8,800). Prognostic factors (tumor ploidy, histology, grade, MKI, LDH, MYCN, 11q, 1p, primary site) were tested for association with age/stage subgroups (Fisher's exact test) and in Cox models. Results: MYCNamplification, 1p aberration, diploidy, and high MKI and LDH were more frequent in infant stage 4 than infant 4s tumors. The incidence of unfavorable biology was higher in toddlers aged 12–18 months, but did not differ with stage 4 vs. 4s pattern. EFS was significantly better for infants <12 months with stage 4s than stage 4 (p=0.0004). EFS was similar for toddlers 12–18 months for stage 4 vs. 4s pattern (p=0.3893). Within the 717 patients with 4s pattern of metastases, age 12–18 months had worse EFS than <12 months (p<0.0001). After adjustment for age in 6 separate models, MYCN, 11q, 1p, MKI, and LDH were statistically significant prognostic factors. Although treatment regimens differed, EFS was similar for <12 months vs. 12–18 months for MYCN not amplified patients in both 4S pattern (p=0.8469) and stage 4 (p=0.3783). Conclusions: For patients with MYCN not amplified tumors, outcome for patients 12–18 months is similar to those <12 months regardless of the pattern of metastases. Tumor biology is more critical than metastatic pattern for prognosis of patients aged 12–18 months with stage 4 neuroblastoma. [Table: see text]

No significant financial relationships to disclose.

Spinal cord neurofibrillary pathology in Alzheimer disease and Guam Parkinsonism-dementia complex

We examined spinal cords of neurodegenerative disease patients and controls living on the Island of Guam and in the continental United States. These patients had pathologically confirmed parkinsonism dementia-complex (PDC) with or without amyotrophic lateral sclerosis (ALS), or Alzheimer disease (AD), respectively. Nearly all of the spinal cords examined from both groups of patients contained neurofibrillary tangles (NFT). The immunohistochemical profile of these NFTs indicates that they are composed of hyperphosphorylated tau protein like their counterparts in the brains of these patients. Western blot analysis confirmed this by revealing that sarcosyl insoluble tau in spinal cord extracts from patients with NFTs exhibited the presence of all 6 tau isoforms similar to that from AD and ALS/PDC cortical gray matter.

Alpha-synuclein in familial Alzheimer disease: epitope mapping parallels dementia with Lewy bodies and Parkinson disease

BACKGROUND

Alpha-synuclein is a major component of Lewy bodies (LBs) in Parkinson disease and dementia with LBs and of glial cytoplasmic inclusions in multiple system atrophy. However, epitope mapping for alpha-synuclein is distinctive in different neurodegenerative diseases. The reasons for this are poorly understood but may reflect fundamental differences in disease mechanisms.

OBJECTIVE

To investigate the alpha-synuclein epitope mapping properties of LBs in familial Alzheimer disease.

DESIGN AND SETTING

We compared LBs in familial Alzheimer disease with those in synucleinopathies by probing 6 brains of persons with familial Alzheimer disease using a panel of antibodies to epitopes spanning the alpha-synuclein protein. Results were compared with data from brains of persons with Parkinson disease, dementia with LBs, and multiple system atrophy.

RESULTS

The brains of persons with familial Alzheimer disease showed consistent staining of LBs with all antibodies, similar to Parkinson disease and dementia with LBs but different from alpha-synuclein aggregates that occurred in multiple system atrophy.

CONCLUSIONS

These data suggest that the epitope profiles of alpha-synuclein in LBs are similar, regardless of whether the biological trigger is related to synuclein or a different genetic pathway. These findings support the hypothesis that the mechanism of alpha-synuclein aggregation is the same within cell types but distinctive between cell types.

Tau isoform profile and phosphorylation state in dementia pugilistica recapitulate Alzheimer's disease

Insights into mechanisms of familial Alzheimer's disease (AD) caused by genetic mutations have emerged rapidly compared to sporadic AD. Indeed, despite identification of several sporadic AD risk factors, it remains enigmatic how or why they predispose to neurodegenerative disease. For example, traumatic brain injury (TBI) predisposes to AD, and recurrent TBI in career boxers may cause a progressive memory disorder associated with AD-like brain pathology known as dementia pugilistica (DP). Although the reasons for this are unknown, repeated TBI may cause DP by mechanisms similar to those involved in AD. To investigate this possibility, we compared the molecular profile of tau pathologies in DP with those in AD and showed that the same tau epitopes map to filamentous tau inclusions in AD and DP brains, while the abnormal tau proteins isolated from DP brains are indistinguishable from the six abnormally phosphorylated brain tau isoforms in AD brains. Thus, these data suggest that recurrent TBI may cause DP by activating pathological mechanisms similar to those that cause brain degeneration due to accumulations of filamentous tau lesions in AD, and similar, albeit attenuated, activation of these processes by a single TBI may increase susceptibility to sporadic AD decades after the event.

Differential expression in an antisense MYCN neuroblastoma model

BACKGROUND

A previously published antisense MYCN-expressing model system was utilized to identify genes whose expression is altered by the down-regulation of MYCN by AS MYCN.

RESULTS

Differential display comparing nontransfected human NB NBL-S cells to three AS MYCN-expressing cell lines (NBAS-4, -5, and -6) yielded nine differentially expressed cDNAs designated NDDE:1-9, for MYCN-dependent differential expression genes. A GenBank search revealed matches for seven of the nine cDNAs. Differential expression was confirmed for five of the cDNAs by Northern blot analysis.

RESULTS

NDDE:8 is up-regulated in the AS MYCN-expressing clones and shares homology with the EB1 clone p53-induced gene (PRG3). NDDE:2 is up-regulated in the high-expressing N-myc protein NBL-S cells and shares homology with a 27 kD heat shock protein PAN1 clone. Further analysis of all five cDNAs might further elucidate the targets of MYCN in NB.

Tau epitopes in spinal cord neurofibrillary lesions in Chamorros of Guam

We examined spinal cord sections from Guamanian Chamorros with or without amyotrophic lateral sclerosis or parkinsonism-dementia complex using immunohistochemistry and antibodies to epitopes that span the length of tau to characterize the tau epitope profile of neurofibrillary tangles in these spinal cords. Most (16/20) spinal cords, including some from Chamorros without documented clinical disease, contained tangles with a tau epitope profile similar to the tangles found in the forebrain and brain stem of these patients.

Synergy between 5' and 3' flanking regions of the human tyrosine hydroxylase gene ensures specific, high-level expression in neuroblastoma cells

Factors regulating tyrosine hydroxylase (TH) gene transcription are of major importance in the studies of malignant and degenerative diseases of catecholamine-synthesizing tissues. In this study, we used transient transfection of a reporter gene to show that high-level, tissue-specific TH expression was only achieved when the reporter gene was cloned between a 5' TH promoter sequence (-513-+1), and, a 3' TH gene flanking sequence (end of exon 14-+976). We also show that TH mRNA expression level is closely linked to the expression level of the proto-oncogene, MYCN in neuroblastoma tumor cell lines. Taken together our data indicate that MYCN may regulate TH expression in neuroblastoma cells, but not through binding to the 5' or 3' TH gene flanking sequences used in our experiments.

Long-term deep brain stimulation in a patient with essential tremor: clinical response and postmortem correlation with stimulator termination sites in ventral thalamus. Case report

Essential tremor can be suppressed with chronic, bilateral deep brain stimulation (DBS) of the ventralis intermedius nucleus (Vim), the cerebellar receiving area of the motor thalamus. The goal in this study was to correlate the location of the electrodes with the clinical efficacy of DBS in a patient with essential tremor. The authors report on a woman with essential tremor in whom chronic bilateral DBS directed to the ventral thalamus produced adequate tremor suppression until her death from unrelated causes 16 months after placement of the electrodes. Neuropathological postmortem studies of the brain in this patient demonstrated that both stimulators terminated in the Vim region of the thalamus, and that chronic DBS elicited minor reactive changes confined to the immediate vicinity of the electrode tracks. Although the authors could not identify neuropathological abnormalities specific to essential tremor, they believe that suppression of essential tremor by chronic DBS correlates with bilateral termination of the stimulators in the Vim region of the thalamus.

Alpha-synuclein cortical Lewy bodies correlate with dementia in Parkinson's disease

BACKGROUND

Dementia is a frequent complication of idiopathic parkinsonism or PD, usually occurring later in the protracted course of the illness. The primary site of neuropathologic change in PD is the substantia nigra, but the neuropathologic and molecular basis of dementia in PD is less clear. Although Alzheimer's pathology has been a frequent finding, recent advances in immunostaining of alpha-synuclein have suggested the possible importance of cortical Lewy bodies (CLBs) in the brains of demented patients with PD.

METHODS

The brains of 22 demented and 20 nondemented patients with a clinical and neuropathologic diagnosis of PD were evaluated with standard neuropathologic techniques. In addition, CLBs and dystrophic neurites were identified immunohistochemically with antibodies specific for alpha-synuclein and ubiquitin; plaques and tangles were identified by staining with thioflavine S. Associations between dementia status and pathologic markers were tested with logistic regression.

RESULTS

CLBs positive for alpha-synuclein are highly sensitive (91%) and specific (90%) neuropathologic markers of dementia in PD and slightly more sensitive than ubiquitin-positive CLBs. They are better indicators of dementia than neurofibrillary tangles, amyloid plaques, or dystrophic neurites.

CONCLUSION

CLBs detected by alpha-synuclein antibodies in patients with PD are a more sensitive and specific correlate of dementia than the presence of Alzheimer's pathology, which was present in a minority of the cases in this series.

Biologic factors determine prognosis in infants with stage IV neuroblastoma: A prospective Children's Cancer Group study

PURPOSE

A prospective Children's Cancer Group study, CCG-3881, has been completed to determine if a more accurate prediction of prognosis by biologic features can identify subgroups of infants with stage IV neuroblastoma (NBL) who require differing intensities of treatment.

PATIENTS AND METHODS

One hundred thirty-four infants were registered from June 1989 to August 1995, with a median follow-up of 47.1 months (range, 0 to 88 months). The biologic factors examined were tumor MYCN copy number, Shimada histopathologic classification, serum ferritin, and bone marrow immunocytology (sensitivity, one tumor cell per 10(5) bone marrow cells). Patients treated on CCG-3881 (n = 116) received four-drug chemotherapy for 9 months (cisplatin, cyclophosphamide, doxorubicin, and etoposide), with surgery and local radiation to residual disease. After January 1991, all subsequent infants with tumor MYCN amplification (n = 18) were transferred after one cycle of therapy to the high-risk CCG-3891 protocol (open January 1991 to April 1996) for more intensive treatment.

RESULTS

The 3-year event-free survival (EFS) and overall survival (mean +/- SD) for the 134 infants were 63% +/- 5% and 71% +/- 5%, respectively. Patients whose tumors were without MYCN amplification had a 93% +/- 4% 3-year EFS, whereas those with amplified MYCN had a 10% +/- 7% 3-year EFS (P <. 0001). Each of the other biologic features studied had prognostic significance in univariate analysis but not after stratifying by MYCN copy number.

CONCLUSION

Infants less than 1 year of age at diagnosis with stage IV NBL have a much improved outcome compared with children >/= 1 year of age. Nonamplified MYCN tumors identify a group of infants with a 93% +/- 4% EFS, whereas amplified MYCN copy number clearly identifies patients who are unlikely to survive despite intensive chemotherapy.

AMY plaques in familial AD: comparison with sporadic Alzheimer's disease

OBJECTIVE

To assess AMY expression in familial AD (FAD).

BACKGROUND

The discovery of nonbeta-amyloid (Abeta), plaque-like deposits composed of a 100-kd protein (AMY) in sporadic AD (SAD) brains prompted us to determine whether these plaques (AMY plaques) also occur in AD due to mutations of the presenilin-1 (PS-1), presenilin-2 (PS-2), or the amyloid precursor protein (APP) genes.

METHODS

We used immunohistochemistry and confocal laser scanning microscopy to probe the brains of 22 patients with FAD (13 with PS-1, 5 with PS-2, and 4 with APP mutations) and 14 patients with SAD.

RESULTS

AMY plaques were present in all SAD and FAD brains, including an FAD/PS-1 brain from an individual with preclinical disease. The morphology of AMY plaques in SAD and FAD brains was indistinguishable, but they differed from Abeta deposits because AMY plaques lacked an immunoreactive core. AMY plaques sometimes colocalized with Abeta(x-42) deposits, but they did not colocalize with Abeta(x-40) plaque cores in either SAD or FAD brains. The percent of cortical area occupied by AMY was greater in FAD than in SAD brains (mean percent area = 9.8% and 5.9%, t = 2.487, p = 0.018). In particular, APP and PS-1 cases had more AMY deposition than PS-2 or SAD cases (12.9%, 10.5%, 6.2% in APP, PS-1, and PS-2 AD).

CONCLUSIONS

AMY plaques are consistently present in familial AD due to presenilin-1 (PS-1), PS-2, and amyloid precursor protein mutations, and they can begin to accumulate before the emergence of dementia.

Spatial relationship of AMY protein deposits and different species of Abeta peptides in amyloid plaques of the Alzheimer disease brain

To further define the spatial relationship of "AMY" plaques detected by antibodies to an unidentified 100 kD AMY protein and amyloid plaques in Alzheimer disease (AD) brains, double immunofluorescence studies were performed with an anti-AMY antibody and a panel of antibodies to different species of Abeta peptides. We report substantial colocalization of AMY immunoreactive plaques with amyloid plaques labeled by antibodies to species of Abeta starting at position 3 with a pyroglutamate modified glutamic acid, however AMY immunoreactive deposits colocalized to a lesser degree with amyloid plaques labeled by antibodies to other variants of the Abeta peptide. Moreover, different immunohistochemical parameters influenced the extent to which colocalization of AMY deposits and Abeta immunoreactive plaques was demonstrable. We conclude that deposits of distinct species of Abeta peptides differentially colocalize with one another and with AMY plaques in the AD brain.

Traumatic brain injury in young, amyloid-beta peptide overexpressing transgenic mice induces marked ipsilateral hippocampal atrophy and diminished Abeta deposition during aging

Traumatic brain injury (TBI) is an epigenetic risk factor for Alzheimer's disease (AD). To test the hypothesis that TBI contributes to the onset and/or progression of AD-like beta-amyloid peptide (Abeta) deposits, we studied the long-term effects of TBI in transgenic mice that overexpress human Abeta from a mutant Abeta precursor protein (APP) minigene driven by a platelet derived (PD) growth factor promoter (PDAPP mice). TBI was induced in 4-month-old PDAPP and wild type (WT) mice by controlled cortical impact (CCI). Because Abeta begins to deposit progressively in the PDAPP brain by 6 months, we examined WT and PDAPP mice at 2, 5, and 8 months after TBI or sham treatment (i.e., at 6, 9, and 12 months of age). Hippocampal atrophy in the PDAPP mice was more severe ipsilateral versus contralateral to TBI, and immunohistochemical studies with antibodies to different Abeta peptides demonstrated a statistically significant reduction in hippocampus and cingulate cortex Abeta deposits ipsilateral versus contralateral to CCI in 9-12 month-old PDAPP mice. Hippocampal atrophy and reduced Abeta deposits were not seen in hippocampus or cingulate cortex of sham-injured PDAPP mice or in any WT mice. These data suggest that the vulnerability of brain cells to Abeta toxicity increases and that the accumulation of Abeta deposits decrease in the penumbra of CCI months after TBI. Thus, in addition to providing unique opportunities for elucidating genetic mechanisms of AD, transgenic mice that recapitulate AD pathology also may be relevant animal models for investigating the poorly understood role that TBI and other epigenetic risk factors play in the onset and/or progression of AD.

Altered expression of the MYCN oncogene modulates MRP gene expression and response to cytotoxic drugs in neuroblastoma cells

We have recently shown a close correlation between expression of the Multidrug Resistance-associated Protein (MRP) gene and the MYCN oncogene and provided evidence that high MRP expression is a powerful independent predictor of poor outcome in neuroblastoma (Norris et al., New Engl. J. Med., 334, 231-238, 1996). The effect of MYCN down-regulation on MRP expression and response to cytotoxic drugs was investigated in NBL-S neuroblastoma cells transfected with MYCN antisense RNA constructs. Concomitant with MYCN down-regulation, the level of MRP expression was decreased in the NBAS-4 and NBAS-5 antisense transfectants. These cells demonstrated significantly increased sensitivity to the high affinity MRP substrates vincristine, doxorubicin, sodium arsenate and potassium antimony tartrate, but not to the poor MRP substrates, taxol or cisplatin. Similarly, transfection of full-length MYCN cDNA into SH-EP neuroblastoma cells resulted in increased MRP expression and significantly increased resistance specifically to MRP substrates. The results provide evidence for the MYCN oncogene influencing cytotoxic drug response via regulation of MRP gene expression. Our data also provide a link between the malignant and chemoresistant phenotypes of this childhood malignancy.

Tau pathology in a family with dementia and a P301L mutation in tau

Familial forms of frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) have recently been associated with coding region and intronic mutations in the tau gene. Here we report our findings on 2 affected siblings from a family with early-onset dementia, characterized by extensive tau pathology and a Pro to Leu mutation at codon 301 of tau. The proband, a 55-year-old woman, and her 63-year-old brother died after a progressive dementing illness clinically diagnosed as Alzheimer disease. Their mother, 2 sisters, maternal aunt and uncle, and several cousins were also affected. Autopsy in both cases revealed frontotemporal atrophy and degeneration of basal ganglia and substantia nigra. Sequencing of exon 10 of the tau gene revealed a C to T transition at codon 301, resulting in a Pro to Leu substitution. Widespread neuronal and glial inclusions, neuropil threads, and astrocytic plaques similar to those seen in corticobasal degeneration were labeled with a battery of antibodies to phosphorylation-dependent and phosphorylation-independent epitopes spanning the entire tau sequence. Isolated tau filaments had the morphology of narrow twisted ribbons. Sarkosyl-insoluble tau exhibited 2 major bands of 64 and 68 kDa and a minor 72 kDa band, similar to the pattern seen in a familial tauopathy associated with an intronic tau mutation. These pathological tau bands predominantly contained the subset of tau isoforms with 4 microtubule-binding repeats selectively affected by the P301L missense mutation. Our findings emphasize the phenotypic and genetic heterogeneity of tauopathies and highlight intriguing links between FTDP-17 and other neurodegenerative diseases.

Antibodies to alpha-synuclein detect Lewy bodies in many Down's syndrome brains with Alzheimer's disease

Immunohistochemical examination of 20 Down's syndrome brains, using antibodies to alpha-, beta-, and gamma-synuclein, demonstrated many alpha-synuclein-positive Lewy bodies and dystrophic neurites in 50% of amygdala samples from Down's syndrome brains with Alzheimer's disease. Similar lesions were less common in other regions of these brains, none of which contained beta-synuclein or gamma-synuclein abnormalities. Thus, alpha-synuclein-positive Lewy bodies and neuritic processes frequently occur with Alzheimer's disease in Down's syndrome brains.

Oxidation of cytosolic proteins and expression of creatine kinase BB in frontal lobe in different neurodegenerative disorders

The presence of the biomarkers of oxidative damage, protein carbonyl formation and the inactivation of oxidatively sensitive brain creatine kinase (CK BB, cytosolic isoform), were studied in frontal lobe autopsy specimens obtained from patients with different age-related neurodegenerative diseases: Alzheimer's disease (AD), Pick's disease (PkD), diffuse Lewy body disease (DLBD), Parkinson's disease (PD), and age-matched control subjects. The CK activity was significantly reduced in the frontal lobe of AD, PkD and DLBD subjects, and CK BB-specific mRNA was significantly reduced in AD and DLBD. Protein carbonyl content was significantly increased in AD, PkD and DLBD. The results of this study confirm that the presence of biomarkers of oxidative damage is related to the presence of histopathological markers of neurodegeneration. Our data suggest that oxidative damage contributes to the development of the symptoms of frontal dysfunction in AD, PkD and DLBD. The development of frontal dysfunction in idiopathic PD might be secondary to oxidative damage and neuronal loss primarily located in the nigrostriatal system. The results of CK BB expression analysis demonstrate that the loss of the isoenzyme in different neurodegenerative diseases is likely the consequence of its posttranslational modification, possibly oxidative damage. Changes in CK BB expression may be an early indicator of oxidative stress in neurons.

A distinct familial presenile dementia with a novel missense mutation in the tau gene

We report a Japanese family with early onset hereditary frontotemporal dementia and a novel missense mutation (Ser305Asn) in the tau gene. The patients presented with personality changes followed by impaired cognition and memory as well as disorientation, but minimal Parkinsonism. Imaging studies showed fronto-temporal atrophy with ventricular dilatation more on the left, and postmortem examination of the brain revealed numerous neurofibrillary tangles (NFTs) with an unusual morphology and distribution. Silver-stained sections showed ring-shaped NFTs partially surrounding the nucleus that were most prominent in frontal, temporal, insular and postcentral cortices, as well as in dentate gyrus. Cortical NFTs were restricted primarily to layer II, and were composed of straight tubules. Numerous glial cells containing coiled bodies and abundant neuropil threads were detected in cerebral white matter, hippocampus, basal ganglia, diencephalon and brain stem, but no senile plaques or other diagnostic lesions were seen. Both the glial and neuronal tangles were stained by antibodies to phosphorylation-independent and phosphorylation-dependent epitopes in tau. Thus, this novel mutation causes a distinct familial tauopathy.

Lewy bodies contain altered alpha-synuclein in brains of many familial Alzheimer's disease patients with mutations in presenilin and amyloid precursor protein genes

Missense mutations in the alpha-synuclein gene cause familial Parkinson's disease (PD), and alpha-synuclein is a major component of Lewy bodies (LBs) in sporadic PD, dementia with LBs (DLB), and the LB variant of Alzheimer's disease (AD). To determine whether alpha-synuclein is a component of LBs in familial AD (FAD) patients with known mutations in presenilin (n = 65) or amyloid precursor protein (n = 9) genes, studies were conducted with antibodies to alpha-, beta-, and gamma-synuclein. LBs were detected with alpha- but not beta- or gamma-synuclein antibodies in 22% of FAD brains, and alpha-synuclein-positive LBs were most numerous in amygdala where some LBs co-localized with tau-positive neurofibrillary tangles. As 12 (63%) of 19 FAD amygdala samples contained alpha-synuclein-positive LBs, these inclusions may be more common in FAD brains than previously reported. Furthermore, alpha-synuclein antibodies decorated LB filaments by immunoelectron microscopy, and Western blots revealed that the solubility of alpha-synuclein was reduced compared with control brains. The presence of alpha-synuclein-positive LBs was not associated with any specific FAD mutation. These studies suggest that insoluble alpha-synuclein aggregates into filaments that form LBs in many FAD patients, and we speculate that these inclusions may compromise the function and/or viability of affected neurons in the FAD brain.

Brain trauma induces massive hippocampal neuron death linked to a surge in beta-amyloid levels in mice overexpressing mutant amyloid precursor protein

Although brain trauma is a risk factor for Alzheimer's disease, no experimental model has been generated to explore this relationship. We developed a model of brain trauma in transgenic mice that overexpress mutant human amyloid precursor protein (PDAPP) leading to the appearance of Alzheimer's disease-like beta-amyloid (Abeta) plaques beginning at 6 months of age. We induced cortical impact brain injury in the PDAPP animals and their wild-type littermates at 4 months of age, ie, before Abeta plaque formation, and evaluated changes in posttraumatic memory function, histopathology, and regional tissue levels of the Abeta peptides Abeta1-40 and Abeta1-42. We found that noninjured PDAPP mice had impaired memory function compared to noninjured wild-type littermates (P < 0.01) and that brain-injured PDAPP mice had more profound memory dysfunction than brain-injured wild-type littermates (P < 0.001). Although no augmentation of Abeta plaque formation was observed in brain-injured PDAPP mice, a substantial exacerbation of neuron death was found in the hippocampus (P < 0.001) in association with an acute threefold increase in Abeta1-40 and sevenfold increase in Abeta1-42 levels selectively in the hippocampus (P < 0.01). These data suggest a mechanistic link between brain trauma and Abeta levels and the death of neurons.

Successful management of concurrent congenital dyserythropoietic anaemia and autoimmune haemolytic anaemia with splenectomy

This first known case of concurrent congenital dyserythropoietic anaemia (CDA) and autoimmune haemolytic anaemia (AIHA) which occurred in a hispanic male and spanned 6 years from the age of 2. Light and electron microscopy of bone marrow erythroblasts and immunophenotyping confirmed CDA; serum/eluate warm autoantibodies and positive direct antiglobulin tests (DAT) associated with severe, episodic anaemias established AIHA. Cytogenetic analysis of bone marrow cells and peripheral blood lymphocytes ascertained sex chromosome aneuploidy (48 XY,+ Y,+ Y). Recurrent, life-threatening episodes of transfusion-dependent anaemia refractory to steroids and intravenous immune globulin, were put into stable remission at age 8 years when splenectomy successfully managed both disorders.

The neuropathology of a chromosome 17-linked autosomal dominant parkinsonism and dementia ("pallido-ponto-nigral degeneration")

A group of similar autosomal dominant hereditary neurodegenerative disorders have been linked to chromosome 17 in thirteen kindreds. One of these disorders, known as pallido-ponto-nigral degeneration (PPND), is characterized by extensive degeneration of the globus pallidus and substantia nigra as well as accumulation of abnormally phosphorylated tau proteins. The authors now present comprehensive data on the cellular and molecular pathology of PPND, allowing its classification among chromosome 17-linked neurodegenerative disorders as well as its classification among sporadic and other familial tauopathies. First, we showed that PPND is characterized by abundant ballooned neurons in neocortical and subcortical regions as well as by tau-rich inclusions in the cytoplasm of neurons and oligodendroglia morphologically similar to those seen in corticobasal degeneration (CBD), but in a distribution pattern resembling progressive supranuclear palsy (PSP). Second, we demonstrated that antibodies to phosphorylation-independent (Alz50, 133, 304, Tau-2, T-46) as well as phosphorylation-dependent (AT8, PHF-6, 12E8, PHF-1, T3P, pS422) epitopes in human tau proteins stain these glial and neuronal inclusions as intensely as they stain CBD or PSP inclusions. Third, we probed PPND brain by Western blots using some of the same anti-tau antibodies to reveal 2 tau immunobands with molecular weights of 69 kD and 64 kD in gray and white matter extracts, as reported for both PSP and CBD. Finally, electron microscopy showed that these abnormal tau proteins formed flat twisted ribbons with a maximum diameter of 20 nanometers (nm) and a periodicity of about 200 nm, resembling those reported in CBD. Based on this, we conclude that PPND is a hereditary neurodegenerative disorder characterized by neuronal and glial tau-rich inclusions formed from aggregated filaments and hyperphosphorylated tau proteins and, hence, can be subcategorized into the tauopathy group of chromosome 17-linked neurodegenerative disorders. Further, since the morphologic and biochemical lesions of PPND overlap with those seen in sporadic CBD and PSP, we speculate that these disorders share common pathogenetic mechanisms.

Activated recombinant human coagulation factor VII therapy for intracranial hemorrhage in patients with hemophilia A or B with inhibitors. Results of the novoseven emergency-use program

Activated recombinant human coagulation factor VII (rFVIIa) is a promising new therapeutic agent for patients with hemophilia A or B with inhibitors who experience serious bleeding episodes or who need coverage during surgical procedures. This open-label, uncontrolled, emergency-use study evaluated the efficacy and safety of rFVIIa in 11 hemophiliac patients and 1 FVII-deficient patient with life-threatening intracranial hemorrhage previously unresponsive to one or more alternative therapies. rFVIIa effectively controlled intracranial hemorrhage in 10 of the 12 patients. Patients with hemophilia A or B received an average of 96.9 rFVIIa injections over 14.7 days with a mean total administration of 153.3 mg, corresponding to 8.1 mg/kg. Most reported adverse events were considered to be unrelated to rFVIIa therapy. These findings suggest that rFVIIa is an effective and well-tolerated therapeutic option in the management of central nervous system bleeding in patients with hemophilia A or B with inhibitors.

Amyloid plaques in Guam amyotrophic lateral sclerosis/parkinsonism-dementia complex contain species of A beta similar to those found in the amyloid plaques of Alzheimer's disease and pathological aging

The Guamanian amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) is characterized by abundant neurofibrillary pathology and neuron loss. In contrast to Alzheimer's disease (AD), where extensive neurofibrillary lesions always occur with deposits of A beta in numerous amyloid plaques, A beta-rich amyloid plaques are absent or rare in most ALS/PDC patients. To characterize the amyloid plaques in the latter patients, we probed plaque-rich sections of their brains by immunohistochemistry using well-characterized antibodies to specific epitopes in the N and C termini of A beta as well as to defined epitopes in hyperphosphorylated tau (PHFtau). The results indicate that the species of A beta in the amyloid plaques of ALS/PDC patients resemble those detected in the amyloid plaques of cognitively intact subjects with pathological aging as well as patients with AD. However, the paucity of PHFtau-positive neurites in the ALS/PDC plaques suggests that they reflect pathological aging rather than AD.

Evidence that the MYCN oncogene regulates MRP gene expression in neuroblastoma

We have recently shown that expression of the multidrug resistance-associated protein (MRP) gene is a powerful prognostic indicator in childhood neuroblastoma and have suggested that the MYCN oncogene may regulate MRP gene expression. To address this hypothesis, we have examined the relationship between MYCN and MRP gene expression in neuroblastoma tumours and cell lines. MYCN and MRP gene expression were highly correlated in 60 primary untreated tumours both with (P = 0.01) and without MYCN gene amplification (P < 0.0001). Like MRP, high MYCN gene expression was significantly associated with reduced survival, both in the overall study population and in older children without MYCN gene amplification (relative hazards = 13.33 and 19.61, respectively). Inhibition of MYCN, through the introduction of MYCN antisense RNA constructs into human neuroblastoma cells in vitro, resulted in decreased MRP gene expression, determined both by RNA-PCR and Western analysis. The data are consistent with MYCN influencing neuroblastoma outcome by regulating MRP gene expression.

Monoclonal antibodies to purified cortical Lewy bodies recognize the mid-size neurofilament subunit

Lewy bodies (LBs) are filamentous intraneuronal inclusions that are hallmark lesions of Parkinson's disease, and LBs have been shown, by immunohistochemistry, to contain cytoskeletal as well as other cellular proteins. Similar LBs also occur in the cortical neurons of a subset of patients with Alzheimer's disease (AD), and cortical LBs are the predominant or sole lesions in the brains of patients with an AD-like dementia known as diffuse Lewy-body disease (DLBD). To gain insight into the biochemical composition of LBs, we generated monoclonal antibodies (mAbs) to LBs purified from the brains of patients with DLBD. Here, we describe three of these new mAbs (LB48, LB202, and LB204) that stained LBs by immunohistochemistry and recognized the medium molecular mass neurofilament (NF) protein in western blots. These results support the hypothesis that NF subunits are integral components of LBs. Continued efforts to clarify the composition of LBs are likely to lead to novel strategies for the antemortem diagnosis of LB disorders as well as to insight into the role LBs play in the degeneration of affected neurons in these disorders.

Autosomal dominant dementia with widespread neurofibrillary tangles

Several familial dementing conditions with atypical features have been characterized, but only rarely is the neuropathology dominated solely by neurofibrillary lesions. We present a Midwestern American pedigree spanning four generations in which 15 individuals were affected by early-onset dementia with long disease duration, with an autosomal dominant inheritance pattern, and with tau-rich neurofibrillary pathology found in the brain post mortem. The average age at presentation was 55 years with gradual onset and progression of memory loss and personality change. After 30 years' disease duration, the proband's neuropathologic examination demonstrated abundant intraneuronal neurofibrillary tangles (NFTs) involving the hippocampus, pallidum, subthalamic nucleus, substantia nigra, pons, and medulla. Only sparse neocortical tangles were present and amyloid plaques were absent. The tangles were recognized by antibodies specific for phosphorylation-independent (Tau-2, T46, 133, and Alz-50) and phosphorylation-dependent epitopes (AT8, T3P, PHF-1, 12E8, AT6, AT18, AT30) in tau proteins. Electron microscopy of NFTs in the dentate gyrus and midbrain demonstrated paired helical filaments. Although the clinical phenotype resembles Alzheimer's disease, and the neuropathologic phenotype resembles progressive supranuclear palsy, an alternative consideration is that this familial disorder may be a new or distinct disease entity.

Betulinic acid induces apoptosis in human neuroblastoma cell lines

Neuroblastoma has long been recognized to show spontaneous regression during fetal development and in the majority of stage 4s infants < 1 year of age with disseminated disease. Stage 4s disease regresses with no chemotherapy in 50% of the patients. The mechanism by which this occurs is not understood but may be programmed cell death or apoptosis. Betulinic acid (BA) has been reported to induce apoptosis in human melanoma with in vitro and in vivo model systems. Melanoma, like neuroblastoma, is derived from the neural crest cell. We hypothesised that neuroblastoma cells have the machinery for programmed cell death and that apoptosis could be induced by betulinic acid. Nine human neuroblastoma cell lines were treated in vitro with BA at concentrations of 0-20 micrograms/ml for 0-6 days. Profound morphological changes were noted within 3 days. Cells withdrew their axonic-like extensions, became non-adherent and condensed into irregular dense spheroids typical of apoptotic cell death (ED50 = 14-17 micrograms/ml). DNA fragmentation analysis showed ladder formation in the 100-1200 bp region in 3/3 neuroblastoma cell lines treated with BA for 24-72 h. Thus, apparently BA does induce AP in neuroblastoma in vitro. This model will be utilised to investigate the role of apoptosis-related genes in neuroblastoma proliferation and to determine the therapeutic efficacy of BA in neuroblastoma in vivo.

Desmoplastic infantile astrocytoma with metastases at presentation

A 4-month-old child presented with nystagmus and macrocephaly. He had a large tumor in the suprasellar and hypothalamic region, as well as two smaller similar masses in the posterior fossa and one in the spinal canal. A biopsy of the suprasellar mass revealed it to be a desmoplastic infantile cerebral astrocytoma. Cerebrospinal fluid obtained at surgery before tumor manipulation showed clusters of malignant cells immunopositive for glial fibrillary acidic protein. In our opinion, the smaller tumors were metastases from the large suprasellar primary astrocytoma. Review of all of the previously reported cases of desmoplastic infantile cerebral astrocytoma and of the related neoplastic entity desmoplastic infantile ganglioglioma suggested that this was a unique case, but we still recommend caution with respect to the previously accepted notion that desmoplastic infantile neuroepithelial tumors are virtually benign neoplasms.

Strategies for improving the postmortem neuropathological diagnosis of Alzheimer's disease

Despite recognition that Alzheimer's disease (AD) is a polygenic and heterogeneous dementing neurodegenerative disorder, there is continued merit in defining the AD phenotype by the presence of progressive cognitive impairments and the pathological brain lesions (senile plaques, neurofibrillary tangles) as originally formulated by Alois Alzheimer. This position paper discusses the rationale for emphasizing the detection of both beta amyloid-rich plaques and tau-rich tangles in the next iteration of the neuropathological criteria for the postmortem diagnosis of AD that has been recommended by the Working Group on Consensus Criteria for the Postmortem Diagnosis of AD. Further, it also underlines the need to exploit continuing advances in understanding the pathobiology of plaques and tangles in subsequent iterations of these criteria. It is expected that such efforts, now and in the future, will hasten the development of strategies for the early and accurate antemortem diagnosis of AD as well as the discovery of effective treatments for this common dementing illness of the elderly.

Monoclonal antibodies to a 100-kd protein reveal abundant A beta-negative plaques throughout gray matter of Alzheimer's disease brains

Here we describe the initial characterization of a 100-kd protein recognized by four new monoclonal antibodies that reveal abundant and unique plaque-like lesions throughout gray matter of Alzheimer's disease brains. This 100-kd protein and these new plaque-like lesions were identified by four monoclonal antibodies raised to immunogens extracted from Alzheimer's disease neurofibrillary abnormalities. However, these antibodies did not recognize hyperphosphorylated tau in Western blots or neurofibrillary lesions by immunohistochemistry. As all of these antibodies displayed similar properties, one, AMY117, was used to characterize the new plaque-like lesions in detail. These studies demonstrated that AMY117-positive plaques were not visualized by amyloid stains and never co-localized with A beta deposits, although AMY117-positive and A beta-positive lesions frequently occurred in the same cortical and subcortical gray matter regions. Abundant AMY117-positive plaques were found in the brains of all 32 sporadic Alzheimer's disease patients and all 6 elderly Down's syndrome subjects. Although AMY117-positive plaques also were seen in the brains of nondemented patients with numerous A beta deposits. AMY117-positive plaques were rare or absent in the brains of other elderly controls and patients with other neurodegenerative or neuropsychiatric disorders. We conclude that the AMY117-positive plaques described here for the first time are major lesions of the Alzheimer's disease brain. Thus, it will be important to elucidate the role played by the 100-kd protein and the AMY117 plaques in the etiology and pathogenesis of Alzheimer's disease.

Modulation of N-myc expression alters the invasiveness of neuroblastoma

N-myc oncogene expression plays a pivotal role in the biology of neuroblastoma, a common childhood tumor. High N-myc expression is associated with advanced disease stage, and in animal models, increased expression results in increased metastatic potential. In normal embryologic development, N-myc expression is associated with neuroblast migration out from the neural crest. To further define the relationship between N-myc and metastasis, an in vitro assay was adapted to measure tumor cell attachment, motility, and proteolytic ability in neuroblastoma cell lines. These parameters were examined in a non-amplified, uniformly N-myc overexpressing cell line and its anti-sense N-myc expressing clones. These lines have been characterized previously, and have a decrease in N-myc expression, growth rate, and tumorigenicity relative to the parent line and vector-only control transfectant. Decrease in N-myc expression resulted in a non-proportional increase of tumor cell attachment, and a proportional decrease in both tumor cell motility and proteolytic ability. In further experiments, assay of a N-myc-amplified overexpressing cell line with an intrinsic heterogeneous pattern of expression demonstrated that motile cells expressed higher amounts of N-myc relative to the general population. Together these relationships indicate that N-myc plays a causative role in the invasive phenotype, and suggest that metastasis may, in part, result from the disruption of a developmentally important normal process.

Identification of phosphorylation sites in PHF-TAU from patients with Guam amyotrophic lateral sclerosis/parkinsonism-dementia complex

Guam Amyotrophic Lateral Sclerosis/Parkinsonism-Dementia Complex (Guam ALS/PDC) is a progressive neurodegenerative disorder characterized by abundant neurofibrillary tangles (NFTs) composed of aggregated paired helical filaments (PHFs). These abnormal filaments resemble the PHFs in neurofibrillary lesions of classic Alzheimer's disease (AD), and recent studies demonstrated that tau in Guam ALS/PDC is aberrantly phosphorylated and biochemically similar to the abnormal tau proteins (PHFtau) in classic AD. However, unlike PHFtau in AD, there is little information on the specific sites of phosphorylation in PHFtau from Guam ALS/PDC. Thus, to address this important issue, we examined tangle-rich Guam ALS/PDC and AD brains by Western blot, immunoelectron microscopy and immunohistochemistry using 13 antibodies to defined phosphate-dependent or -independent epitopes distributed throughout AD PHFtau. These studies identified 7 previously unknown sites of phosphorylation in PHFtau from Guam ALS/PDC (i.e. Thr181, Thr231, Ser262, Ser396, Ser404, Ser422, and the site defined by monoclonal antibody AT10), all of which also are found in AD PHFtau. Indeed, the Western blot, light and immunoelectron microscopic data suggest that NFTs, PHFs and PHFtau in Guam ALS/PDC are very similar to their counterparts in classic AD. Thus, insights into mechanisms leading to the accumulation of neurofibrillary lesions in Guam ALS/PDC may advance understanding of the pathogenesis and biological consequences of these lesions in classic AD.

Neurofibrillary tangles in progressive supranuclear palsy contain the same tau epitopes identified in Alzheimer's disease PHFtau

Neurofibrillary tangle (NFT)-rich brain samples from patients with progressive supranuclear palsy (PSP) or Alzheimer's disease (AD) were probed with a large panel of anti-tau antibodies to compare the species of tau present in PSP and AD NFTs by immunohistochemistry and Western blot methods. These antibodies have been shown to recognize phosphate-independent or -dependent epitopes that extend from the amino to the carboxy terminal domains of normal brain tau and the abnormal tau in the paired helical filaments (PHFs) of AD NFTs (PHFtau). The immunohistochemical studies showed that all of the tau epitopes detected in brainstem PSP NFTs also were found in hippocampal AD NFTs and vice versa. While Western blots demonstrated 2 PHFtau-like immunobands in PSP brainstem, a triplet of PHFtau proteins were seen in the AD and PSP hippocampus. Despite differences in the distribution, ultrastructure and immunoblot profile of NFTs in PSP and AD, the same constellation of tau epitopes is present in the abnormal tau proteins in PSP and AD NFTs. Thus, the generation of abnormal tau proteins in PSP (PSPtau) and AD (PHFtau) may have similar adverse biological consequences in both diseases.

Convergence of Lewy bodies and neurofibrillary tangles in amygdala neurons of Alzheimer's disease and Lewy body disorders

Amygdalae of patients with Alzheimer's disease (AD), Parkinson's disease, Down's syndrome, diffuse Lewy body disease or a combination of these diseases were probed with antibodies to neurofilament proteins as well as with Lewy body (LB)- and paired helical filament-specific antibodies. The results indicate that the amygdala is severely affected by the accumulation of both neurofibrillary tangles (NFTs) and LBs in most cases of the diseases mentioned above, and that amygdala LBs have a similar epitope composition to that of LBs in the brain stem and cerebral cortex. While large numbers of both LBs and NFTs were seen in different neurons within the amygdala, these two lesions frequently occurred together in the same neurons of the amygdala. These findings are in contrast to other sites that accumulate LBs and NFTs, but rarely both lesions in the same neuron. Thus, amygdala neurons may be selectively vulnerable to developing both LBs and NFTs, and these inclusions may play a role in the massive degeneration of these neurons in AD and LB disorders of the elderly.

Paired helical filament tau (PHFtau) in Niemann-Pick type C disease is similar to PHFtau in Alzheimer's disease

Niemann-Pick Type C disease (NPC) is a cholesterol storage disease with defects in the intracellular trafficking of exogenous cholesterol derived from low density lipoproteins. In NPC cases with a chronic progressive course, neurofibrillary tangles (NFTs) that consist of paired helical filaments (PHFs) have been reported. To determine if NPC tangles contain abnormal tau proteins (known as PHFtau) similar to those found in Alzheimer's disease (AD) tangles, we examined the brains of five NPC cases by immunohistochemical and Western blot methods using a library of antibodies to defined epitopes of PHFtau. We show here that PHFtau in tangle-rich NPC brains is indistinguishable from PHFtau in AD brains. We speculate, that the generation of PHFtau in NPC may induce a cascade of pathological events that contribute to the widespread degeneration of neurons, and that these events may be similar in NPC and AD.

Association of apolipoprotein epsilon 4 allele and neuropathologic findings in patients with dementia

Apolipoprotein E (APOE) is a lipoprotein expressed in liver and brain as one of three isoforms (APOE 2, APOE 3 and APOE 4). Recent findings suggest that the presence of APOE 4 is associated with an increased risk for both familial Alzheimer's disease and late-onset Alzheimer's disease. We extended these observations by determining the frequency of APOE alleles in patients with pathologically confirmed Alzheimer's Disease (AD), Parkinson's disease (PD), diffuse Lewy Body disease (DLBD), AD with concomitant PD pathology, demented PD patients without or with concomitant AD pathology and in schizophrenics with a progressive dementia (SCHIZ+DEM). The APOE genotype was determined by restriction digestion of polymerase chain reaction-amplified DNA isolated from frozen brain samples. The frequency of the APOE epsilon 4 allele was highest among sporadic AD and DLBD patients (0.30 and 0.38, respectively) and lowest in the SCHIZ+DEM and non-demented PD patients (0.06 and 0.1, respectively). Thus, the APOE epsilon 4 allele is over-represented selectively in patients with dementias associated with plaques and tangles and/or cortical Lewy bodies, but not in demented schizophrenics or non-demented PD patients.