Investigating the Pathogenic Interplay of Alpha-Synuclein, Tau, and Amyloid Beta in Lewy Body Dementia: Insights from Viral-Mediated Overexpression in Transgenic Mouse Models

Lewy body dementia (LBD) is an often misdiagnosed and mistreated neurodegenerative disorder clinically characterized by the emergence of neuropsychiatric symptoms followed by motor impairment. LBD falls within an undefined range between Alzheimer's disease (AD) and Parkinson's disease (PD) due to the potential pathogenic synergistic effects of tau, beta-amyloid (Aβ), and alpha-synuclein (αsyn). A lack of reliable and relevant animal models hinders the elucidation of the molecular characteristics and phenotypic consequences of these interactions. Here, the goal was to evaluate whether the viral-mediated overexpression of αsyn in adult hTau and APP/PS1 mice or the overexpression of tau in Line 61 hThy1-αsyn mice resulted in pathology and behavior resembling LBD. The transgenes were injected intravenously via the tail vein using AAV-PHP.eB in 3-month-old hThy1-αsyn, hTau, or APP/PS1 mice that were then aged to 6-, 9-, and 12-months-old for subsequent phenotypic and histological characterization. Although we achieved the widespread expression of αsyn in hTau and tau in hThy1-αsyn mice, no αsyn pathology in hTau mice and only mild tau pathology in hThy1-αsyn mice was observed. Additionally, cognitive, motor, and limbic behavior phenotypes were not affected by overexpression of the transgenes. Furthermore, our APP/PS1 mice experienced premature deaths starting at 3 months post-injection (MPI), therefore precluding further analyses at later time points. An evaluation of the remaining 3-MPI indicated no αsyn pathology or cognitive and motor behavioral changes. Taken together, we conclude that the overexpression of αsyn in hTau and APP/PS1 mice and tau in hThy1-αsyn mice does not recapitulate the behavioral and neuropathological phenotypes observed in LBD.

Honokiol decreases alpha-synuclein mRNA levels and reveals novel targets for modulating alpha-synuclein expression

Background

Intracytoplasmic inclusions comprised of aggregated alpha-synuclein (αsyn) represent a key histopathological feature of neurological disorders collectively termed "synucleinopathies," which includes Parkinson's disease (PD). Mutations and multiplications in the SNCA gene encoding αsyn cause familial forms of PD and a large body of evidence indicate a correlation between αsyn accumulation and disease. Decreasing αsyn expression is recognized as a valid target for PD therapeutics, with down-regulation of SNCA expression potentially attenuating downstream cascades of pathologic events. Here, we evaluated if Honokiol (HKL), a polyphenolic compound derived from magnolia tree bark with demonstrated neuroprotective properties, can modulate αsyn levels in multiple experimental models.

Methods

Human neuroglioma cells stably overexpressing αsyn, mouse primary neurons, and human iPSC-derived neurons were exposed to HKL and αsyn protein and SNCA messenger RNA levels were assessed. The effect of HKL on rotenone-induced overexpression of αsyn levels was further assessed and transcriptional profiling of mouse cortical neurons treated with HKL was performed to identify potential targets of HKL.

Results

We demonstrate that HKL can successfully reduce αsyn protein levels and SNCA expression in multiple in vitro models of PD with our data supporting a mechanism whereby HKL acts by post-transcriptional modulation of SNCA rather than modulating αsyn protein degradation. Transcriptional profiling of mouse cortical neurons treated with HKL identifies several differentially expressed genes (DEG) as potential targets to modulate SNCA expression.

Conclusion

This study supports a HKL-mediated downregulation of SNCA as a viable strategy to modify disease progression in PD and other synucleinopathies. HKL has potential as a powerful tool for investigating SNCA gene modulation and its downstream effects.

APOE2 Exacerbates TDP-43 Related Toxicity in the Absence of Alzheimer Pathology

OBJECTIVE

Recent evidence supports a link between increased TDP-43 burden and the presence of an APOE4 gene allele in Alzheimer's disease (AD); however, it is difficult to conclude the direct effect of APOE on TDP-43 pathology due to the presence of mixed AD pathologies. The goal of this study is to address how APOE isoforms impact TDP-43 pathology and related neurodegeneration in the absence of typical AD pathologies.

METHODS

We overexpressed human TDP-43 via viral transduction in humanized APOE2, APOE3, APOE4 mice, and murine Apoe-knockout (Apoe-KO) mice. Behavior tests were performed across ages. Animals were harvested at 11 months of age and TDP-43 overexpression-related neurodegeneration and gliosis were assessed. To further address the human relevance, we analyzed the association of APOE with TDP-43 pathology in 160 postmortem brains from autopsy-confirmed amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with motor neuron disease (FTLD-MND) in the Mayo Clinic Brain Bank.

RESULTS

We found that TDP-43 overexpression induced motor function deficits, neuronal loss, and gliosis in the motor cortex, especially in APOE2 mice, with much milder or absent effects in APOE3, APOE4, or Apoe-KO mice. In the motor cortex of the ALS and FTLD-MND postmortem human brains, we found that the APOE2 allele was associated with more severe TDP-43-positive dystrophic neurites.

INTERPRETATION

Our data suggest a genotype-specific effect of APOE on TDP-43 proteinopathy and neurodegeneration in the absence of AD pathology, with the strongest association seen with APOE2. ANN NEUROL 2023;93:830-843.

In Vivo Detection of Extracellular Adenosine Triphosphate in a Mouse Model of Traumatic Brain Injury

Traumatic brain injury (TBI) is traditionally characterized by primary and secondary injury phases, both contributing to pathological and morphological changes. The mechanisms of damage and chronic consequences of TBI remain to be fully elucidated, but synaptic homeostasis disturbances and impaired energy metabolism are proposed to be a major contributor. It has been proposed that an increase of extracellular (eATP) adenosine triphosphate (ATP) in the area immediately surrounding impact may play a pivotal role in this sequence of events. After tissue injury, rupture of cell membranes allows release of intracellular ATP into the extracellular space, triggering a cascade of toxic events and inflammation. ATP is a ubiquitous messenger; however, simple and reliable techniques to measure its concentration have proven elusive. Here, we integrate a sensitive bioluminescent eATP sensor known as pmeLUC, with a controlled cortical impact mouse model to monitor eATP changes in a living animal after injury. Using the pmeLUC probe, a rapid increase of eATP is observed proximal to the point of impact within minutes of the injury. This event is significantly attenuated when animals are pretreated with an ATP hydrolyzing agent (apyrase) before surgery, confirming the contribution of eATP. This new eATP reporter could be useful for understanding the role of eATP in the pathogenesis in TBI and may identify a window of opportunity for therapeutic intervention.

Incidence, survival, and risk of cardiovascular events in adult inflammatory myopathies in South Korea: a nationwide population-based study

OBJECTIVE

Epidemiological studies on inflammatory myopathies (IMs) show widely variable results, and studies on Asians are lacking. Despite emerging interest in the cardiovascular disease (CVD) risk associated with IMs, the prevalence of CVD in IM patients and its impact on mortality remain unclear. We conducted a nationwide, population-based study on the incidence, mortality, and associated major CVD events of IMs in the Republic of Korea over 11 years.

METHOD

Using the nationwide, population-based National Health Insurance claims database and the Rare Intractable Disease registration programme, we estimated incidence, mortality, and CVD occurrence. Survival was examined using the Kaplan-Meier method. Mortality rate in IMs with CVD was analysed by Cox proportional hazards regression.

RESULTS

There were 3014 incident cases, 640 of whom died during the study period. The mean annual incidence was 7.16/10⁶. Dermatomyositis (DM) and polymyositis (PM) had 5 year survival rates of 76.8% and 79.3%, respectively. Cardiovascular events occurred in 155 patients and 40.6% of IM patients with CVD died. Acute myocardial infarction in men had the highest risk of any CVD event in both DM [standardized incidence ratio (SIR) 4.2, 95% confidence interval (95% CI) 2.4-7.2] and PM (SIR 3.5, 95% CI 1.8-7.0). Haemorrhagic stroke had the highest hazard ratio (HR) in both DM (HR 2.31, 95% CI 1.13-4.70) and PM patients (HR 2.10, 95% CI 1.03-4.27) compared with the general population with CVD.

CONCLUSION

We found persistently low incidence, poor survival, and high major CVD incidence in IMs, and increased mortality in IMs with CVD.

Paediatric acute disseminated encephalomyelitis followed by optic neuritis: disease course, treatment response and outcome

BACKGROUND AND PURPOSE

Acute disseminated encephalomyelitis followed by optic neuritis (ADEM-ON) is a rare demyelinating syndrome that is different from multiple sclerosis and neuromyelitis optica spectrum disorder. The aim of this study was to describe the disease course, treatment response and outcome of children with ADEM-ON.

METHODS

Children of <18 years of age were identified from six countries of the EU Paediatric Demyelinating Disease Consortium. Patients fulfilled the diagnostic criteria for ADEM followed by at least one ON. Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies were tested in all patients.

RESULTS

In this study of 17 patients (nine boys) with ADEM-ON, anti-myelin oligodendrocyte glycoprotein (MOG) antibodies were identified in 16 patients. Age at onset was 6.1 years (interquartile range, 5.1-9.2 years). Twelve patients received oral prednisolone and 10 received maintenance immunosuppression (e.g. azathioprine, intravenous immunoglobulins, Rituximab). During a follow-up of 5.3 years (interquartile range, 1.8-10.2 years), 54 relapses occurred with a median of 3 relapses per patient (range, 1-9 per patient). Patients relapsed on all treatments but no relapses occurred on a prednisolone dose >10 mg/day. Visual and cognitive residual deficits were common in this group.

CONCLUSIONS

Acute disseminated encephalomyelitis followed by optic neuritis is an anti-MOG antibody-associated relapsing disorder that can have a heterogeneous disease course. Patients were refractory for maintenance immunosuppression and appeared to be corticosteroid-dependent. Further international collaborations are now required to unify guidelines in this difficult-to-manage group of patients.

Severe acute disseminated encephalomyelitis: a paediatric intensive care population-based study

There is a paucity of literature on the epidemiology of severe acute disseminated encephalomyelitis (ADEM). We describe a Paediatric Intensive Care Unit (PICU) population-based study to determine the epidemiology and clinical characteristics of children with ADEM requiring PICU admission or resulting in death. Anonymized data from the Paediatric Intensive Care Audit Network (PICANet) were obtained for all children under 16 years with a diagnosis of ADEM admitted to 25 PICUs in England and Wales (2004–2008). The Office for National Statistics (ONS) mortality database was also searched. In total, 27 PICANet cases (13 females:14 males; median age 4.8 years) were ascertained and all were alive on discharge. In addition, three cases were identified from the ONS mortality database. Of the 27 PICANet cases, clinical features included; seizures ( n = 5); upper airway respiratory obstruction/stridor ( n = 2); unspecified encephalopathy ( n = 27); and polyfocal neurological deficits ( n = 6). The median duration of ventilation was 3 days. Inotropic support was required in 4/27 patients, and one patient had invasive intracranial pressure monitoring. None received plasmapheresis. We conclude that the incidence of childhood ADEM admitted to the PICU in England and Wales is approximated at 0.5 per million children/year, thus representing approximately one quarter of children admitted with ADEM (denominator: 2009 Canadian surveillance data).

Nine-year audit of post-dural puncture headache in a tertiary obstetric hospital in Singapore

BACKGROUND

The KK Women's and Children's Hospital is a tertiary obstetric unit with approximately 11000 deliveries per year. Epidural analgesia is used in about 40% of laboring women. We reviewed the incidence and management of post-dural puncture headache over a nine-year period.

METHODS

A retrospective audit of labor epidural analgesia database records from 1 June 2005 to 31 May 2014 was conducted, identifying an "event" as an accidental dural puncture, an inadvertent intrathecal catheter insertion and/or development of a post-dural puncture headache.

RESULTS

A total of 43434 epidural records were reviewed. Sixty-three events were identified (an incidence of 0.15%). Women had median age of 30years and median body mass index of 27.6kg/m²; 69.8% (44/63) delivered vaginally. Procedures performed by less experienced anesthesiologists and those performed outside office hours were associated with a higher incidence of accidental dural puncture. An intrathecal catheter was inserted in 52 of 58 women (89.7%). Headache developed in 24 of 38 (63.1%) women in whom there was a witnessed accidental dural puncture. Most women who developed post-dural puncture headache presented during the primary admission (36/39; 92.3%). Paracetamol and non-steroidal anti-inflammatory drugs were the most commonly prescribed medications. Six women (9.5%) received an epidural blood patch which led to resolution of headache.

CONCLUSION

A retrospective audit over a nine-year period at a tertiary teaching hospital found the overall incidence of post-dural puncture headache and associated events to be 0.15%, with a decreasing trend coinciding with improvement in the teaching and supervision of trainees in labor epidural procedures.

Paediatric multiple sclerosis: examining utility of the McDonald 2010 criteria

The new McDonald 2010 criteria have been recommended in paediatric multiple sclerosis (PMS). We aimed to assess the utility of McDonald 2010 criteria in comparison with 2007 International Paediatric Multiple Sclerosis Study Group (IPMSSG)-recommended criteria for PMS diagnosis. Retrospective analysis of 38 PMS cases from three UK demyelination clinics was conducted. Dissemination in space (DIS) and time (DIT) for both McDonald and IPMSSG criteria were noted on initial and follow-up magnetic resonance imaging (MRI). At first MRI scan, IPMSSG DIS criteria were fulfilled in 68% of scans and McDonald DIS criteria in 84%. In total, 11/18 children given gadolinium contrast fulfilled both McDonald DIS and DIT criteria on initial scan. The 2010 McDonald criteria appear more sensitive than IPMSSG and may allow PMS diagnosis at first presentation of CIS in at least a half of cases.

Proximal hip geometry and hip fracture risk assessment in a Korean population

The association between proximal femoral geometry and hip fracture risk were investigated. The risk of intertrochanteric fractures increased 1.64-fold and 2.32-fold with 1 standard deviation (sd) increase of hip axis length and neck-shaft angle, respectively, while the risk of femur neck fracture 2.03-fold with 1 sd decrease in femoral head offset.

INTRODUCTION

The purpose of this study was to determine the association between proximal femoral geometry (PFG) and the risk of hip fracture in femur neck (FN) and intertrochanteric (IT) fractures in a Korean population.

METHODS

The study included 151 patients (57 patients with IT fractures, 43 patients with FN fractures, and 51 control patients). Data on BMD, PFG parameters (hip axis length [HAL], neck-shaft angle [NSA], neck length, femoral head offset, neck diameter, shaft diameter (SD), and demographics [age, gender, height, and body weight]) were collected. Descriptive statistics and odds ratios of PFG parameters corrected with demographic variables were obtained using logistic regressions.

RESULTS

HAL (p = 0.046) and NSA (p = 0.003) were significantly greater in the patients with IT fracture than in the control patients, while neither parameter was significantly greater in patients with FN fractures than the control patients. The femoral head offset was significantly shorter in the patients with FN fractures (p = 0.003) compared with the control patients. In patients with IT fractures, the fracture risk increased 1.64-fold (p = 0.048) with a 1 sd increase of the HAL, while it increased 2.32-fold (p = 0.003) with a 1 sd increase of the NSA. In FN fractures, the fracture risk increased 2.03-fold (p = 0.012) with a 1 sd decrease in femoral head offset.

CONCLUSIONS

Our study showed that some PFG parameters as well as BMD values predict hip fractures in a Korean population, and their evaluation may be useful in the understanding of the biomechanics of hip fractures.

Aicardi-Goutières syndrome presenting with haematemesis in infancy

Aicardi-Goutières syndrome is a genetic childhood encephalopathy characterized by basal ganglia calcification, chronic cerebrospinal lymphocytosis and elevated cerebrospinal fluid interferon-alpha, mimicking acquired congenital viral infections. As more is discovered about the pathogenesis of Aicardi-Goutières, it is becoming evident that a dysfunction of the immune system is likely to be responsible for the disease phenotype. We describe a previously healthy 2-month-old female infant who presented with haematemesis and seizures and was subsequently diagnosed with Aicardi-Goutières syndrome. To our knowledge, this is the first documented case of Aicardi-Goutières syndrome presenting with haematemesis. The gastrointestinal tract is an area of high cell loss, revealing early signs of systemic inflammation and we postulate that a systemic proinflammatory milieu occurs in Aicardi-Goutières syndrome.

CONCLUSION

Aicardi-Goutières syndrome can present with haematemesis, adding to the growing evidence that the Aicardi-Goutières syndrome spectrum encompasses an immune-mediated multisystem involvement. Gastrointestinal inflammation should also be considered in these patients and treated appropriately.

Distinct patterns of serum immunoreactivity as evidence for multiple brain-directed autoantibodies in juvenile neuronal ceroid lipofuscinosis

Autoantibodies to glutamic acid decarboxylase (GAD65) have been reported in sera from the Cln3(-/-) mouse model of juvenile neuronal ceroid lipofuscinosis (JNCL), and in individuals with this fatal paediatric neurodegenerative disorder. To investigate the existence of other circulating autoreactive antibodies, we used sera from patients with JNCL and other forms of neuronal ceroid lipofuscinosis (NCL) as primary antisera to stain rat and human central nervous system sections. JNCL sera displayed characteristic patterns of IgG, but not IgA, IgE or IgM immunoreactivity that was distinct from the other forms of NCL. Immunoreactivity of JNCL sera was not confined to GAD65-positive (GABAergic) neurons, but also stained multiple other cell populations. Preadsorption of JNCL sera with recombinant GAD65 reduced the intensity of the immunoreactivity, but did not significantly change its staining pattern. Moreover, sera from Stiff Person Syndrome and Type I Diabetes, disorders in which GAD65 autoantibodies are present, stained with profiles that were markedly different from JNCL sera. Collectively, these studies provide evidence of the presence of autoreactive antibodies within multiple forms of NCL, and are not exclusively directed towards GAD65.

Angular dependence of the dipole-dipole interaction in a nearly one-dimensional sample of Rydberg atoms

Atoms in an ultracold highly excited sample are strongly coupled through the dipole-dipole interaction. In an effort to understand and manipulate the complicated interactions in this system we are investigating their dependence on the relative orientation of the dipoles. By focusing a 480 nm beam from a tunable dye laser into a magneto-optical trap, we produce a nearly one-dimensional sample of Rydberg atoms. The trap lies at the center of four conducting rods with which we can vary the magnitude and direction of the electric field at the trap, thus controlling the orientation of the dipoles with respect to the sample axis. We have measured the strength of the interaction for a variety of relative orientations.

Electron temperature of ultracold plasmas

We study the evolution of ultracold plasmas by measuring the electron temperature. Shortly after plasma formation, competition between heating and cooling mechanisms drives the electron temperature to a value within a narrow range regardless of the initial energy imparted to the electrons. In agreement with theory predictions, plasmas exhibit values of the Coulomb coupling parameter Gamma less than 1.

Comparative analyses of multi-species sequences from targeted genomic regions

The systematic comparison of genomic sequences from different organisms represents a central focus of contemporary genome analysis. Comparative analyses of vertebrate sequences can identify coding and conserved non-coding regions, including regulatory elements, and provide insight into the forces that have rendered modern-day genomes. As a complement to whole-genome sequencing efforts, we are sequencing and comparing targeted genomic regions in multiple, evolutionarily diverse vertebrates. Here we report the generation and analysis of over 12 megabases (Mb) of sequence from 12 species, all derived from the genomic region orthologous to a segment of about 1.8 Mb on human chromosome 7 containing ten genes, including the gene mutated in cystic fibrosis. These sequences show conservation reflecting both functional constraints and the neutral mutational events that shaped this genomic region. In particular, we identify substantial numbers of conserved non-coding segments beyond those previously identified experimentally, most of which are not detectable by pair-wise sequence comparisons alone. Analysis of transposable element insertions highlights the variation in genome dynamics among these species and confirms the placement of rodents as a sister group to the primates.

Association of HLA-DR and type II collagen autoimmunity with Meniere's disease

To investigate HLA-associated genetic susceptibility to Meniere's disease in relation to type II collagen (CII) autoimmunity status, HLA-DRB1 genotyping and ELISA measurement of anti-CII antibody were performed in 41 Korean patients with Meniere's disease. In the anti-CII positive subgroup (20%) of patients, the frequency of HLA-DRB1*0405 was significantly increased (uncorrected) compared with both controls (63% vs 16%) and anti-CII negative patients (63% vs 12%). In the anti-CII negative subgroup, HLA-DRB1*1201 was significantly increased (uncorrected) (27% vs 10%) and DRB1*13 was decreased (6% vs 24%) compared with controls; these alleles appeared to confer susceptibility and resistance to the development of the disease. Association of HLA-DRB1*0405 with anti-CII positive Meniere's disease in this study suggests that it shares a specific HLA-DR sequence, QRRAA, as a genetic susceptibility factor with the anti-CII positive rheumatoid arthritis. In conclusion, whilst type II collagen autoimmunity may have a partial role in Meniere's disease, different HLA-DR alleles may also be associated with either susceptibility or resistance to the development of the disease in relation to anti-CII antibody status.

Inflammation-induced subcellular redistribution of VE-cadherin, actin, and gamma-catenin in cultured human lung microvessel endothelial cells

The inflammation-induced subcellular redistribution of key cytoskeletal and junctional proteins in cultured human lung microvessel endothelial cells is investigated as part of a study on the posttranslational regulation of paracellular permeability. Inflammatory agonist-stimulated cells are detergent fractionated into three subcellular compartments followed by quantitative immunoblot analysis. Actin, gamma-catenin, and VE-cadherin increasingly associate with the cytoskeletal fraction upon thrombin stimulation. Concomitantly, actin is reduced in the cytosol fraction, whereas gamma-catenin and VE-cadherin are reduced in the membrane fraction. alpha- and beta-catenin show baseline distributions similar to those of VE-cadherin and gamma-catenin, but do not significantly redistribute. Additionally, vimentin is found exclusively in the cytoskeletal fraction and also does not significantly redistribute following thrombin treatment. The VE-cadherin response is independent of the presence of F-actin or actin redistribution. Immunofluorescence microscopy reveals that membrane and cytoskeletal VE-cadherin is present in alternating patches along the cell junctions. Furthermore, VE-cadherin is lost from zones of interendothelial cell pore formation. A model is formulated describing these membrane-associated VE-cadherin patches as predetermined zones of potential intercellular gap formation. During inflammation, VE-cadherin is lost from these zones and sequestered at the remaining cell-cell contact sites, anchored to the cytoskeleton in an actin-independent fashion.

Formation of Rydberg atoms in an expanding ultracold neutral plasma

We study the formation of Rydberg atoms in expanding plasmas at temperatures of 1-1000 K and densities from 10(5)-10(10) cm(-3). Up to 20% of the initially free charges recombine in about 100 micros, and the binding energy of the Rydberg atoms approximately equals the increase in the kinetic energy of the remaining free electrons. Three-body recombination is expected to dominate in this regime, yet most of our results are inconsistent with this mechanism.

NFkappaB translocation in human microvessel endothelial cells using a four-compartment subcellular protein redistribution assay

Protein distribution profiles may be used to characterize both physiological and pathophysiological cellular changes, but rigorous biochemical assays for measuring such movements are lacking. This paper reports on a protein redistribution assay that combines reversible metal chelate-based total protein detection with a four-fraction subcellular detergent fractionation procedure. TNF-alpha stimulated cultured human omental microvessel endothelial cells are fractionated into cytosol, membrane/organelle, nuclear (envelope and associated), and cytoskeletal/DNA compartments. Protein fractions are separated electrophoretically and electroblotted or slot-blotted onto PVDF membranes without electrophoretic separation. A key feature is that total protein is measured and analyzed directly on the resultant PVDF membrane, using a Ferrozine/ferrous metal-chelate stain, without the added step of a prior solution-phase protein assay. As a result, factors that may adversely affect NFkappaB quantification, such as saturation of the solid-support membrane, are rigorously evaluated and controlled. Following removal of the Ferrozine/ferrous total protein stain, NFkappaB distribution is determined via standard immunodetection procedures. This assay reveals a new level of complexity regarding NFkappaB distribution and translocation. NFkappaB is shown to translocate from the cytosol to the membrane/organelle and cytoskeletal/DNA fractions, whereas trace levels of NFkappaB are observed in the nuclear (envelope and associated) fraction. Dose-curve analysis reveals that the response is initiated at 10 U/ml of TNF-alpha, plateaus at approximately 1000 U/ml, and remains essentially constant up to 2000 U/ml. Time-course analysis demonstrates a measurable response as early as 5 min and a peak response at approximately 30 min, after which the distribution begins to return to baseline. The assay should provide a valuable tool for rapid evaluation and mechanistic studies of NFkappaB redistribution.

The type II peroxiredoxin gene family of the mouse: molecular structure, expression and evolution

Peroxiredoxins (Prxs) are a newly defined family of antioxidant proteins that have been implicated, via their antioxidant activity, in a number of cellular functions, including cell proliferation and differentiation, protection of other proteins from oxidative damage, and intracellular signaling. We isolated genomic DNA sequences of the type II Prx (Prx II) gene from the mouse and analyzed their molecular genetic characteristics. In the mouse, the Prx II is found to form a small multigene family with three members. One of them, the Prx II-1 gene, is actively transcribed in a variety of adult tissues as well as in the developing embryos to produce a 1.1-kb mRNA. The Prx II-1 gene consists of six exons and five introns, and the whole transcription unit occupies about 4.5 kb in the mouse genome. The other two genes, Prx II-2 and Prx II-3, are encoded by single exons, and show 97.5 and 87% of nucleotide sequence homology with the Prx II-1 gene, respectively. Structural features of these genes and the results of RT-PCR analysis on RNAs from various tissue sources indicate that the Prx II-2 and Prx II-3 genes could be pseudogenes derived from the Prx II-1 gene by a mechanism involving retrotransposition. These results strongly suggest that only the Prx II-1 gene might be relevant for studying the function of the Prx II gene in the murine system.

Momordins inhibit both AP-1 function and cell proliferation

The activation of Jun/Fos is a crucial factor in transmitting the tumor promoting signal from the extracellular environment to nuclear transcription machinery. One of the final steps in signal transduction is the binding of Jun/Fos to the AP-1 site in order to express gene transcription. Utilizing this concept, we screened about 100 extracts of natural plants to search for a Jun-Fos function inhibitor. The methanol extract of Ampelopsis radix reduced Jun/Foc retardation remarkably. The active principles of the extract were isolated and purified by repeated column chromatography and their structures were identified as oleanolic acid glycosides known as momordin I, Id, and Ie. These compounds reduced the Jun/Fos-DNA interaction and their activities were quantitated with liquid scintillation counting of corresponding bands. Among them, momordin I had the strongest inhibitory activity, with an IC50 value of 22.8 micrograms/ml. The methanol extract and momordin I, Id and Ie also showed cell cytotoxicity against human cancer cell lines. As expected from a gel shift assay, momordin I showed the strongest cytotoxicity and its IC50 value was from 7.280 micrograms/ml to 16.05 micrograms/ml depending on the cell line. With these data, it may be concluded that the mechanism of anticancer activity of momordin I comes from its inhibitory effect on the protein-DNA interaction. The in vivo test was done only with the methanol extract. The extract showed measurable anticancer activity against murine colon cancer. The wet tumor weight reduction rate was 17.73% at 90 mg/kg dose. We suggest that the Jun/Fos-DNA interaction results in cell cytotoxicity.

A luminescent europium complex for the sensitive detection of proteins and nucleic acids immobilized on membrane supports

Certain metal complexes selectively interact with proteins immobilized on solid-phase membrane supports to form brightly colored products. Detecting the absorbance of colorimetric stains is limited by the molar extinction coefficient of the product, however. Development of light-emitting complexes should improve detection sensitivity, but fluorescent labels described to date modify free amino, carboxyl, or sulfhydryl groups often rendering proteins unsuitable for further analysis. Bathophenanthroline disulfonate (BPSA) forms a luminescent europium (Eu) complex that reversibly binds to proteins and nucleic acids. Analysis of charge-fractionated carrier ampholytes and synthetic polymers of different L-amino acids indicates that protein binding is chiefly through protonated alpha- and epsilon-amino side chains. Proteins or nucleic acids immobilized to a nitrocellulose or polyvinyl difluoride membrane by electroblotting, dot-blotting, or vacuum slot-blotting are incubated with the lanthanide complex at acidic pH. Membranes are rinsed, illuminated with UV light and the phosphorescence of BPSA-Eu is measured at 590 to 615 nm using a CCD camera or spectrofluorimeter. The linear dynamic range of the stain is 476- and 48-fold for protein and DNA, respectively. A strong chelating agent such as ethylenediaminetetraacetic acid combined with a shift to basic pH (PH 8-10) elutes BPSA-Eu from the membrane. The reversible nature of the protein staining procedure allows for subsequent biochemical analyses, such as immunoblotting, lectin staining, and mass spectrometry.

Solid-phase metal chelate assay for quantifying total protein: resistance to chemical interference

Recently, we developed reversible metal chelate stains that are fully compatible with immunoblotting and protein sequencing. Membrane supports are incubated in Ferrozine/ferrous complex followed by ferrocyanide/ferric complex (double-metal chelate [DMC] stain). Proteins are quantified by computerized densitometry. In this study, the metal chelate stains are used for routine protein quantitation. Manually applying samples to membranes leads to variable spot spreading. Better results are achieved using a slot-blot apparatus to maintain a constant application area. The Ferrozine/ferrous and DMC assays are compared to colloidal gold and bicinchroninic acid (BCA) assays with respect to chemical interference, protein-to-protein variation, dynamic linear range and sensitivity. The DMC assay provides a superior linear range (100-fold range) and BCA assays (47-fold). Though the colloidal gold assay is more sensitive, it suffers from poor reproducibility, high protein-to-protein variation and lower tolerance to interfering agents. The BCA assay has the least protein-to-protein variation but is also least sensitive and most susceptible to interfering agents.

Pyrogallol red-molybdate: a reversible, metal chelate stain for detection of proteins immobilized on membrane supports

Certain metal complexes selectively interact with proteins immobilized on solid-phase membrane supports to form brightly colored products. The metal chelates form protein-dye complexes in the presence of metal ions at acidic pH but are eluted from the proteins by immersing membranes in a solution of basic pH that contains other chelating agents. The reversible nature of the protein staining procedure allows for subsequent biochemical analyses, such as immunoblotting, N-terminal and internal protein sequencing. Among the metal complexes evaluated to date, the triazine dye-ferrous complexes (ferene S, ferrozine) and the ferrocyanide-ferric complexes provide the most sensitive detection of proteins immobilized on membranes. While the pyrogallol red-molybdate complex is commonly used in solution-based total protein assays, its utility as a reversible stain for proteins immobilized on membranes has not been reported. Pyrogallol red-molybdate complexes readily stain proteins on nitrocellulose and polyvinyl difluoride membranes with similar sensitivity as ferrozine-ferrous complexes. Analysis of charge-fractionated carrier ampholytes and synthetic polymers of different L-amino acids indicate that binding is prominently via protonated alpha and epsilon-amino side chains. Carbamylation of amino groups in bovine serum albumin substantially diminishes pyrogallol red-molybdate binding to the protein. The stain is reversible, resistant to chemical interference, and compatible with immunoblotting.

Regional effects of myocardial ischemia on epicardially recorded canine first heart sounds

To determine whether focal changes in myocardial material properties are important in determining the response of first heart sound acceleration amplitude and frequency to myocardial ischemia, cardiac vibrations were simultaneously recorded from ischemic and nonischemic regions of canine epicardium by use of ultralight acceleration transducers. Cardiac acceleration and hemodynamics were recorded before and 5 min, 15 min, 1 h, and 2 h after left circumflex coronary artery occlusion. Peak-to-peak amplitude declined transiently in the nonischemic zone during early occlusion (P < 0.05) but was not decreased at any time in the ischemic myocardium. The median frequency of first heart sound vibrations in the ischemic region increased 31% within 5 min after occlusion (P < 0.01) and remained elevated for 2 h (P < 0.05). Nonischemic zone frequency was not statistically different from baseline at any time point. The disparate regional response of first heart sound vibrational frequency to myocardial ischemia suggests that propagating mechanical transients and myocardial contractile acceleration, rather than resonant vibrations, produce the first heart sound.

Rapid reduction of left ventricular hypertrophy in acromegaly after suppression of growth hormone hypersecretion

OBJECTIVE

To examine the possible role of growth hormone as a pathogenetic factor in the development of myocardial hypertrophy in acromegaly.

DESIGN

An uncontrolled clinical trial.

SETTING

Tertiary-care medical center.

PATIENTS

Sixteen patients with acromegaly were stratified into two groups: Group I (n = 10) had left ventricular hypertrophy (LVH), and group II (n = 6) did not have LVH.

INTERVENTION

Therapy with octreotide acetate (SMS 201-995), a long-acting somatostatin analog (mean dose, 538 micrograms/d), was administered for 2 months.

MEASUREMENTS

Plasma growth hormone and insulin-like growth factor I (IGF-I) concentrations, hand volume, and echocardiographic left ventricular dimensions and mass were measured at baseline and at 1 week and 2 months after the start of therapy.

RESULTS

Before octreotide therapy, both groups had similar hand volumes and similar growth hormone and IGF-I hypersecretion. Both groups showed a reduction in growth hormone at 2 months (mean reduction, 13.7 micrograms/L in patients with LVH [P < 0.01] and 14.1 micrograms/L in patients without LVH [P < 0.05]). Plasma IGF-I was also decreased (mean reduction, 305 micrograms/L in patients with LVH [P < 0.01] and 304 micrograms/L in patients without LVH [P < 0.05]). Reduction of growth hormone and IGF-I hypersecretion in patients with LVH was associated with a rapid decrease in left ventricular mass (339 g to 299 g, P < 0.01) within 1 week, which was sustained at 2 months (274 g, P < 0.04). Patients without LVH showed no statistical change in left ventricular mass. In patients with LVH, the decrease in left ventricular mass correlated with the octreotide-induced decrease in growth hormone (r = 0.79, P less than 0.05) but not with blood pressure. Blood pressure, left ventricular dimensions, and percent of fractional shortening were not altered by therapy in either group. Hand volume decreased in both groups.

CONCLUSIONS

Normalization of growth hormone secretion is associated with reduction of left ventricular mass in acromegalic patients with LVH within 1 week of initiating therapy with octreotide.

Ischemic expansion during acute myocardial infarction and reversal by coronary reperfusion

Previous studies have shown that infarct expansion occurs at least 1 day after a large transmural infarction. To assess whether regional left ventricular expansion is evident within hours of an acute myocardial infarction, 25 adult mongrel dogs underwent left circumflex coronary artery occlusion for 2 hours and 22 of these were subsequently reperfused. Two-dimensional echocardiography was used to record left ventricular topography and function at baseline, at 2 hours of occlusion, and following reperfusion. Short-axis midpapillary echocardiograms were analyzed using a microcomputer digitizing routine by establishing a 360-degree circumferential map of the left ventricle. The central ischemic zone was defined as that region with the most depressed contractility after 2 hours of occlusion, and the normal zone was set at 180 degree away from the central ischemic zone. Endocardial and epicardial segment lengths and wall thickness were measured for both the normal zone and the central ischemic zone at end diastole. After 2 hours of occlusion, diastolic central ischemic endocardial (1.3 +/- 0.05 to 1.42 +/- 0.04 cm, p less than 0.01) and central ischemic epicardial (1.84 +/- 0.06 to 1.93 +/- 0.06 cm, p less than 0.05) segment lengths were significantly increased. There were no significant changes in segment lengths or wall thickness in the normal zone. After 2 hours of occlusion, there was significant diastolic left ventricular (LV) dilatation (LV area increased from 18.2 +/- 1.3 to 21.0 +/- 1.3 cm2, p less than 0.01). Furthermore, central ischemic endocardial and epicardial segment length changes from baseline to occlusion correlated significantly with LV dilatation (r = 0.56, p less than 0.003; r = 0.55, p less than 0.004 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler echocardiography in the evaluation of left ventricular diastolic function

The examination of diastolic filling velocities by Doppler echocardiography has provided increasing insights into the understanding of left ventricular diastolic performance in health and disease. However, several recent studies have emphasized the importance of a wide variety of physiologic variables, including heart rate, respiration, age, and loading conditions that need to be considered as potential confounding factors in the interpretation of these filling patterns. Despite this, Doppler echocardiographic assessment has been useful in the evaluation and prognostication of a variety of restrictive cardiomyopathies. Furthermore, the study of Doppler diastolic filling velocities has improved our understanding of common cardiac diseases, including hypertensive and ischemic myocardial disease. Further enhancement of our understanding of left ventricular diastolic filling in health and disease will depend on more precise elucidation of the mechanisms responsible for diastolic function.

Effect of coronary reocclusion after initial reperfusion on ventricular function and infarct size

Reocclusion of a coronary artery after thrombolytic therapy occurs in approximately 12% to 33% of patients; however, there are few experimental data concerning reocclusion. Accordingly, to compare the effects of reocclusion versus sustained occlusion on the myocardium, a canine model (n = 12) of 2 h of left circumflex artery occlusion, 1 h of reperfusion and 1 h of reocclusion was studied. In a control group (n = 11), 3 h of circumflex artery occlusion was followed by 1 h of reperfusion. As a result, both groups had the same total duration of ischemia (3 h) and reperfusion (1 h). Hemodynamic measurements, radioactive microsphere injections and two-dimensional echocardiography were performed at baseline, occlusion and reperfusion for both groups and at the end of reocclusion for the experimental group. In vivo risk area was determined with Evans blue dye and infarct size with triphenyltetrazolium staining methods. Similar decreases in myocardial blood flow after coronary occlusion and similar reperfusion blood flows occurred in both groups. Despite intervening reperfusion in the reocclusion group, no significant difference was found in the infarct size/risk area ratio between the reocclusion and control groups (54.5 +/- 6.9% vs. 48.4 +/- 5.1%, respectively, p = NS). Two-dimensional echocardiography demonstrated a similar degree and extent (159 +/- 9 degrees vs. 153 +/- 12 degrees, p = NS) of left ventricular dysfunction with both the occlusion and reocclusion. In addition, there were no significant differences in global or regional left ventricular function between the two groups. However, reocclusion after reperfusion did produce a further deterioration in ischemic zone wall thickening (9.5 +/- 2.0% to 0.7 +/- 1.8%, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Transient left ventricular filling abnormalities (diastolic stunning) after acute myocardial infarction

A variety of experimental studies suggest that diastolic left ventricular (LV) function changes after acute myocardial infarction (AMI), but limited data exist on these changes in humans. To assess diastolic filling after AMI, 60 patients underwent Doppler echocardiographic examination within 24 hours of AMI. Of 54 patients who also underwent catheterization, 45 (83%) were successfully reperfused. A subgroup of 17 patients underwent a follow-up Doppler examination at 7 days after infarction, whereas 15 patients with stable exertional angina served as control subjects. There was no significant difference in age, gender, incidence of systemic hypertension or diabetes mellitus, heart rate, mean arterial pressure or severity of coronary artery disease between the infarct and control groups. The infarct group had a lower velocity time integral total (9.9 +/- 0.4 cm vs 12.0 +/- 0.9 cm, p less than 0.001), a lower velocity time integral E (5.8 +/- 0.3 cm vs 6.8 +/- 0.5 cm, p less than 0.01) and a lower velocity time integral 0.333 (3.5 +/- 0.4 cm vs 6.1 +/- 0.5 cm, p less than 0.01) than the control group. In addition, velocity time integral A/total was significantly greater in the infarction group (0.44 +/- 0.03 vs 0.35 +/- 0.04, p less than 0.01) compared to the control group. The follow-up subgroup showed an increase in velocity time integral total (p less than 0.01), velocity time integral E (p less than 0.05) and velocity time integral 0.333/total (p less than 0.05) over the first 7 days after infarction. The final recovery values at 7 days were not significantly different from those of the coronary artery disease group.(ABSTRACT TRUNCATED AT 250 WORDS)

Posterior ciliary-artery occlusion after subcutaneous silicone-oil injection

Visual loss occurred after subcutaneous silicone-oil injection for cosmetic purposes. To our knowledge, this is the first instance of amaurosis caused by a subcutaneous foreign-material injection that spared the central retinal artery and affected portions of the posterior ciliary-artery distribution, including a probable cilioretinal artery. The visual-field defects produced allow a rare opportunity to view the distribution of the human posterior ciliary-artery circulation by means of this in vivo pathologic embolic process. The facial arterial anatomy pertinent to ocular embolism is also discussed.