The role of intestine in metabolic dysregulation in murine Wilson disease

BACKGROUND

The clinical manifestations of Wilson disease (WD) are related to copper accumulation in the liver and the brain, but little is known about other tissue involvement regarding metabolic changes in WD. In vitro studies suggested that the loss of intestinal ATP7B affects metabolic dysregulation in WD. We tested this hypothesis by evaluating the gut microbiota and lipidome in 2 mouse models of WD and by characterizing a new mouse model with a targeted deletion of Atp7b in the intestine.

METHODS

Cecal content 16S sequencing and untargeted hepatic and plasma lipidome analyses in the Jackson Laboratory toxic-milk and the Atp7b null global knockout mouse models of WD were profiled and integrated. Intestine-specific Atp7b knockout mice (Atp7bΔIEC) were generated and characterized using targeted lipidome analysis following a high-fat diet challenge.

RESULTS

Gut microbiota diversity was reduced in animal models of WD. Comparative prediction analysis revealed amino acid, carbohydrate, and lipid metabolism functions to be dysregulated in the WD gut microbial metagenome. Liver and plasma lipidomic profiles showed dysregulated triglyceride and diglyceride, phospholipid, and sphingolipid metabolism in WD models. However, Atp7bΔIEC mice did not show gut microbiome differences compared to wild type. When challenged with a high-fat diet, Atp7bΔIEC mice exhibited profound alterations to fatty acid desaturation and sphingolipid metabolism pathways as well as altered APOB48 distribution in intestinal epithelial cells.

CONCLUSIONS

Gut microbiome and lipidome underlie systemic metabolic manifestations in murine WD. Intestine-specific ATP7B deficiency affected both intestinal and systemic response to a high-fat challenge but not the microbiome profile, at least at early stages. WD is a systemic disease in which intestinal-specific ATP7B loss and diet influence the phenotype and the lipidome profile.

Systematic Evaluation of Copper(II)-Loaded Immobilized Metal Affinity Chromatography For Selective Enrichment of Copper-Binding Species in Human Serum and Plasma

Copper is essential in a host of biological processes, and disruption of its homeostasis is associated with diseases including neurodegeneration and metabolic disorders. Extracellular copper shifts in its speciation between healthy and disease states, and identifying molecular components involved in these perturbations could widen the panel of biomarkers for copper status. While there have been exciting advances in approaches for studying the extracellular proteome with mass-spectrometry-based methods, the typical workflows disrupt metal-protein interactions due to the lability of these bonds either during sample preparation or in gas-phase environments. We sought to develop and apply a workflow to enrich for and identify protein populations with copper-binding propensities in extracellular fluids using an immobilized metal affinity chromatography (IMAC) resin. The strategy was optimized using human serum to allow for maximum quantity and diversity of protein enrichment. Protein populations could be differentiated based on protein load on the resin, likely on account of differences in abundance and affinity. The enrichment workflow was applied to plasma samples from patients with Wilson disease (WD) and protein IDs and differential abundancies compared to healthy subjects were compared to those yielded from a traditional proteomic workflow. While the IMAC workflow preserved differential abundance and protein ID information from the traditional workflow, it identified several additional proteins being differentially abundant including those involved in lipid metabolism, immune system, and antioxidant pathways. Our results suggest the potential for this IMAC workflow to identify new proteins as potential biomarkers in copper-associated disease states.

DNA Hydroxymethylation in Smoking-Associated Cancers

5-hydroxymethylcytosine (5-hmC) was first detected in mammalian DNA five decades ago. However, it did not take center stage in the field of epigenetics until 2009, when ten-eleven translocation 1 (TET1) was found to oxidize 5-methylcytosine to 5-hmC, thus offering a long-awaited mechanism for active DNA demethylation. Since then, a remarkable body of research has implicated DNA hydroxymethylation in pluripotency, differentiation, neural system development, aging, and pathogenesis of numerous diseases, especially cancer. Here, we focus on DNA hydroxymethylation in smoking-associated carcinogenesis to highlight the diagnostic, therapeutic, and prognostic potentials of this epigenetic mark. We describe the significance of 5-hmC in DNA demethylation, the importance of substrates and cofactors in TET-mediated DNA hydroxymethylation, the regulation of TETs and related genes (isocitrate dehydrogenases, fumarate hydratase, and succinate dehydrogenase), the cell-type dependency and genomic distribution of 5-hmC, and the functional role of 5-hmC in the epigenetic regulation of transcription. We showcase examples of studies on three major smoking-associated cancers, including lung, bladder, and colorectal cancers, to summarize the current state of knowledge, outstanding questions, and future direction in the field.

Attention Deficits and ADHD Symptoms in Adults with Fabry Disease-A Pilot Investigation

The present pilot study examines subjective reported symptoms of attention-deficit/hyperactivity (AD/H) in adults with Fabry disease (FD) in comparison with existing normative control data. Existing data from 69 adults with FD via the Achenbach System of Empirically Based Assessment Adult Self-Report questionnaire were analyzed. The results demonstrated a higher prevalence of AD/H symptoms in adults with FD than in the general United States population, with a roughly equal endorsement of Inattention/Attention Deficit symptoms (AD), Hyperactivity-Impulsivity (H-I) symptoms, and Combined Inattention/hyperactivity-impulsivity (C) symptoms. No gender differences were observed. While all subjects endorsing H-I symptoms fell into the symptomatic range on the AD/H scale, only two-thirds of subjects endorsing AD did so. This suggests that attention difficulties with FD are not solely explained by ADHD. Adults with FD who endorsed the AD, H-I, and C symptoms were also more likely to report mean adaptive functioning difficulties. These findings support the growing literature regarding attention difficulties in adults with FD, as well as suggesting a previously unrecognized risk of AD/H symptoms. Future research involving the objective assessment of ADHD in adults with FD is recommended. When serving adults with FD clinically, healthcare professionals should address multiple areas of care, including physical, psychological, and cognitive arenas.

Correction to: Stingray spear injury to the pediatric spinal cord: case report and review of the literature

The original version of this article unfortunately contained an error in the spelling of the last name of one of the co-authors. The corresponding author did not notice that the last name of one of the co-authors, Nathan Shlobin, was misspelled as "Schlobin". The correct spelling of his last name is "Shlobin". Given in this article is the corrected author name.

Stingray spear injury to the pediatric spinal cord: case report and review of the literature

Stingray injuries are rare, mostly causing injuries to the lower extremities but occasionally fatal if there is direct puncture of the thorax, abdomen, or neck. Direct combined stingray injury to the central nervous system has not been reported in the literature. Herein we present the case of a 12-year-old boy who, while wading at the seashore of the Costa Rica's Pacific Ocean, sustained a combined oblique penetrating injury to the C6 vertebra caused by a Stingray. He initially presented to the hospital with a complete asymmetric right C6/left T1 ASIA A examination, priapism, and loss of anal sphincter tone. Imaging revealed fracture of the posterior elements of C6 with an oblique trajectory into the left radicular foramen. T2W images did not reveal anatomical section but rather edema and minor bleeding in the epidural space. The patient underwent medical management and serial imaging. During the next 3 months, there was recovery of sensation on the right hemi body, bilateral paresthesias and asymmetric progressive improvement in strength on both legs. Acute care management and midterm term follow up are provided, along with a review of the literature for salient management considerations when evaluating and treating combined penetrating and envenomation injuries caused by stingrays. To our knowledge, this is the first report of such injury to the spine.

FRI0056 LUNG COMPROMISE SCREENING IN PATIENTS WITH EARLY RA. A MULTICENTRIC CROSS SECTIONAL STUDY

Background:

Rheumatoid arthritis (RA) affects 0.4-1.3% of general population (1). It can affect lungs in different ways, with interstitial lung disease (ILD) as the most severe. Clinically evident ILD has been reported in 10-42% of patients, with a great impact in prognosis (2).

Objectives:

Toidentify the prevalence of lung involvement in early rheumatoid arthritis patients (ERA) without previous known lung disease and describe the association between high resolution computed tomography (HRCT), lung functional tests (LFT) and clinical findings.

Methods:

Cross sectional multicentric study. We included ERA patients (1 year or less since diagnose) consecutively. Patients with previous RA related lung disease or biologic/targeted synthetic Dmard treatment were excluded. HRCT, immunological tests (rheumatoid factor, anti-CCP, ANA), LFT and clinical evaluation were performed.

Results:

We included 74 patients, 63 (85,1%) woman, mean (SD) of 47 (17,7) years. Thirty-seven patients (50%) were current or former smokers. Abnormal findings in HRCT were found in 62 patients (88,6%): ILD in 6 (8,6%), airway involvement in 40 (70%) and emphysema in 7 (10%). Ten patients (13,5%) had abnormal auscultation (2 sibilances, 2 roncus, and 6 crackles). Six patients (8,1%) had digital clubbing. Regarding immunological tests, 54/61 (88,5%) patients were positive for Anti CCP, and 53/61 (86,9%) were positive for FR. We compared features of patients with findings related to RA in HRCT (interstitial and/or airway) with those without them. We found no differences in the mean (SD) of DAS-28 [4,74 (1,38) vs 4,32 (1,39); p= 0,27]. The prevalence of anti- CCP was not higher in patients with abnormal HRCT [38/44 (86,3%) vs 16/17 (94,1%); p=0,39]. Patients with abnormal HRCT were older [median (IQR) 50,5 years (44,5-59,5) vs 43 years (32-51); p=0,008) and showed higher VSG values [mean (SD) 39,09 (24,03) vs 27,38 (17,6); p= 0,043]. Abnormal physical examination or dyspnea (class 2 mMRC or higher) was significantly associated with HRCT abnormalities [26 (50%) vs 3 (13,6%); p=0.003) and the presence of ILD on HRCT was significantly associated with crackles on the auscultation [4/68(6,25%) vs 2/6 (33,33%); p 0,023].

Conclusion:

This study shows a high prevalence of lung involvement in ERA patients of less 1 year from diagnosis. Also, we showed a significant association between HRCT and physical examination findings. This data highlights the importance of the clinical examination in Rheumatoid Arthritis patients. More studies with bigger samples and longitudinal follow up are needed to confirm and complete our results.

References:

[1]Rooney BK, Silman AJ. Epidemiology of the rheumatic diseases. Curr Opin Rheumatol [Internet]. 1999 Mar [cited 2016 Jul 19];11(2):91–7. Available from:http://www.ncbi.nlm.nih.gov/pubmed/10319210.

[2]Antin-Ozerkis D, Evans J, Rubinowitz A, Homer RJ, Matthay RA. Pulmonary Manifestations of Rheumatoid Arthritis. Clin Chest Med [Internet]. 2010;31(3):451–78. Available from:http://dx.doi.org/10.1016/j.ccm.2010.04.003.

Disclosure of Interests:

None declared

Hypomethylation of LINE-1 repeat elements and global loss of DNA hydroxymethylation in vapers and smokers

The outbreak of vaping-related severe lung injuries and deaths and the epidemic of teen vaping in the U.S. underscore the urgent need for determining the biological consequences of electronic cigarette (e-cig) use. We have investigated the association between vaping and epigenetic changes by quantifying DNA methylation levels in Long Interspersed Nucleotide Element 1 (LINE-1) and global DNA hydroxymethylation (5-hmC) levels and measuring the expression level of enzymes catalysing the respective processes in peripheral blood of exclusive vapers, smokers, and controls, matched for age, gender, and race (n = 45). Both vapers and smokers showed significant loss of methylation in LINE-1 repeat elements in comparison to controls (P = 0.00854 and P = 0.03078, respectively). Similarly, vapers and smokers had significant reductions in 5-hmC levels relative to controls (P = 0.04884 and P = 0.0035, respectively). Neither the LINE-1 methylation levels nor the global 5-hmC levels were different between vapers and smokers. There was a direct correlation between methylation levels in the LINE-1 elements and global 5-hmC levels in the study subjects (r = 0.31696, P = 0.03389). Inverse and statistically significant correlations were found between both the LINE-1 methylation levels and the global 5-hmC levels and various vaping/smoking metrics in the study subjects. There were modest but not statistically significant changes in transcription of DNA methyltransferases and ten-eleven translocation enzymes in both vapers and smokers relative to controls. Our findings support follow-up genome-wide investigations into the epigenetic effects of vaping, which may further clarify the health consequences of e-cig use.

ABBREVIATIONS

5-mC: 5-methylcytosine; 5-hmC: 5-hydroxymethylcytosine; 8-OHdG: 8-hydroxy-2'-deoxyguanosine; ACTIN: actin beta; ANOVA: Analysis of Variance; BER: base excision repair; BMI: body mass index; CO: carbon monoxide; COHb: carboxyhaemoglobin; COBRA: combined bisulphite restriction analysis; COPD: chronic obstructive pulmonary disease; DNMT1: DNA methyltransferase 1; DNMT3A: DNA methyltransferase 3A; DNMT3B: DNA methyltransferase 3B; e-cigs: electronic cigarettes; ELISA: enzyme-linked immunosorbent assay; ENDS: electronic nicotine delivery systems; FDA: Food and Drug Administration; GAPDH; glyceraldehyde-3-phosphate dehydrogenase; HPLC: high-performance liquid chromatography; LINE-1: Long Interspersed Nucleotide Element 1; PBS: phosphate-buffered saline; RFU: relative fluorescence units; RT-qPCR: quantitative reverse-transcription polymerase chain reaction; ROS: reactive oxygen species; SAM, S-adenosylmethionine; SE: standard error; TET1: ten-eleven translocation 1; TET2: ten-eleven translocation 2; TET3: ten-eleven translocation 3.

Surface Attachment Enhances the Thermodynamic Stability of Protein L

Despite the importance of protein-surface interactions in both biology and biotechnology, our understanding of their origins is limited due to a paucity of experimental studies of the thermodynamics behind such interactions. In response, we have characterized the extent to which interaction with a chemically well-defined macroscopic surface alters the stability of protein L. To do so, we site-specifically attached a redox-reporter-modified protein variant to a hydroxy-terminated monolayer on a gold surface and then used electrochemistry to monitor its guanidine denaturation and determine its folding free energy. Comparison with the free energy seen in solution indicates that interaction with this surface stabilizes the protein by 6 kJ mol^-1 , a value that is in good agreement with theoretical estimates of the entropic consequences of surface-induced excluded volume effects, thus suggesting that chemically specific interactions with this surface (e.g., electrostatic interactions) are limited in magnitude.

Cystosonographic measurements of canine bladder tumours

The purpose of this study was to evaluate the variability of cystosonographic bladder tumor measurements with both operator and bladder volume changes. Ten dogs with bladder tumors were included. In each dog, three operators determined tumor dimensions for three different bladder volumes. Intraclass correlation coefficient was used to assess operator reliability. Response Evaluation Criteria in Solid Tumors (RECIST) and greater than or equal to 50% differences in tumor measurements were used as guidelines. Poor to fair correlations between operators were found for the different tumor dimensions (r(I) = 0.4 - 0.7). The percent differences in tumor dimensions with operator and bladder volume changes were significant enough to misclassify the tumors into the categories of partial response (PR) or progressive disease (PD). These results suggest that cystosonographic measurements of bladder tumors are affected by both changes in operator and bladder volume, and the discrepancies are significant enough to change response classification.

Extended pelvic resections for recurrent uterine and cervical cancer: out-of-the-box surgery

Patients with recurrent uterine and cervical cancer have poor prognoses. The objective of this study was to analyze the outcomes of patients with recurrent uterine and cervical cancer who had undergone attempted curative resection of pelvic bone, sidewall muscle, major blood vessels, and/or nerves. We reviewed the records of all 14 patients with recurrent uterine and cervical cancer who had extended pelvic resections at our institution between June 2000 and November 2006. Primary sites of disease were the uterus (11 patients) and cervix (3 patients). Tumor histology was as follows: adenocarcinoma, seven; squamous cell carcinoma, three; leiomyosarcoma, three; and adenosarcoma, one. Previous treatment included hysterectomy, 11; pelvic radiation, 9; chemotherapy, 9; and total pelvic exenteration, 2. Extended pelvic resections included removal of pelvic sidewall muscle, five; bone, five; common and/or external iliac vessel, five; femoral nerve, two; lumbosacral nerve root, one; and obturator nerve, one. Other procedures included total pelvic exenteration, three; posterior exenteration, two; and anterior exenteration, one. Complete resection with negative margins was obtained in 11 (78%) of 14 patients. Seven patients (50%) received high-dose rate intraoperative radiation therapy. Reconstructive procedures included continent or incontinent urinary diversion, four; femoral-femoral arterial bypass, two; myocutaneous flap, two; and urinary ileal interposition, one. Median total operating time was 628 min (range, 345-935 min) and median estimated blood loss was 900 mL (range, 300-16,000 mL). Seven patients (50%) had one or more major complication(s), including pelvic abscess, three; colonic fistula, two; massive intraoperative hemorrhage, one; postoperative bladder perforation, one; thrombosed femoral-femoral graft, one; and disruption of appendicocutaneous urinary anastomosis, one. At a median follow-up of 26 months (range, 5-84 months), ten patients (71%) are alive and four patients (29%) have died of disease at 8, 13, 33, and 42 months postoperatively.

Furanocoumarins from the aerial parts of Dorstenia contrajerva

A new glycosylated furanocoumarin, alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranosyl-bergaptol (1), has been isolated from Dorstenia contrajerva together with three known furanocoumarins, catechin and epicatechin. Their structures were established using high field 2D NMR techniques.

Evidence for the involvement of Tiam1 in axon formation

In cultured neurons, axon formation is preceded by the appearance in one of the multiple neurites of a large growth cone containing a labile actin network and abundant dynamic microtubules. The invasion-inducing T-lymphoma and metastasis 1 (Tiam1) protein that functions as a guanosine nucleotide exchange factor for Rac1 localizes to this neurite and its growth cone, where it associates with microtubules. Neurons overexpressing Tiam1 extend several axon-like neurites, whereas suppression of Tiam1 prevents axon formation, with most of the cells failing to undergo changes in growth cone size and in cytoskeletal organization typical of prospective axons. Cytochalasin D reverts this effect leading to multiple axon formation and penetration of microtubules within neuritic tips devoid of actin filaments. Taken together, these results suggest that by regulating growth cone actin organization and allowing microtubule invasion within selected growth cones, Tiam1 promotes axon formation and hence participates in neuronal polarization.

Tau protein function in axonal formation

Tau protein is a predominantly neuronal microtubule-associated protein that is enriched in axons and is capable of promoting microtubule assembly and stabilization. In the present article we review some of the key experiments directed to obtain insights about tau protein function in developing neurons. Aspects related to whether or not tau has essential, unique, or complementary functions during axonal formation are discussed.

Studies on the constituents of Gliricidia sepium (Leguminosae) leaves and roots: isolation and structure elucidation of new triterpenoid saponins and aromatic compounds

Our research program on the Central American fooder plant Gliricidia sepium led to the discovery of two new triterpene saponins (1 and 2) and known aromatic compounds. The new compounds possess 3beta,21beta, 24-trihydroxy-22-oxoolean-12-ene as an aglycon. The oligosaccharide moiety linked to C-3 of the aglycon contained two pyranoses (glucuronic acid and xylose); in addition the glucose residue of both 1 and 2 is also linked to C-21. Structure elucidation of these new compounds through the extensive use of 1D and 2D NMR techniques have provided detailed information about the sapogenin and the saccharide chains, inclusive of sugar sequence and the position of glycosylation.

New 12a-hydroxyrotenoids from gliricidia sepium bark

The investigation of a methanolic extract of Gliricidia sepium bark afforded, in addition to vestitol and 2'-O-methylvestitol, three new 12a-hydroxyrotenoids, gliricidol (1), 2-methoxygliricidol (2), and gliricidin (3). The structures of 1-3 were elucidated by analysis of their spectroscopic data. Compounds 1-3 exhibited activity against Artemia salina larvae.

Iridoids from Lippia graveolens

An investigation of the leaves of Lippia graveolens from Guatemala provided 10 iridoid and secoiridoid glucosides as well as their ester derivatives. Minor constituents were loganin, secologanin, secoxyloganin, dimethylsecologanoside, loganic acid, 8-epi-loganic acid and caryoptoside. Major constituents were the novel iridoids caryoptosidic acid and lippioside I and II consisting of caryoptosidic acid esterified at the C-6 position of glucose with p-coumaroyl or caffeoyl residues, respectively. Their structures were mainly elucidated by NMR spectroscopy.

Kinesin-mediated organelle translocation revealed by specific cellular manipulations

The distribution of membrane-bound organelles was studied in cultured hippocampal neurons after antisense oligonucleotide suppression of the kinesin-heavy chain (KHC). We observed reduced 3,3'-dihexyloxacarbocyanine iodide (DiOC6(3)) fluorescent staining in neurites and growth cones. In astrocytes, KHC suppression results in the disappearance of the DiOC6(3)-positive reticular network from the cell periphery, and a parallel accumulation of label within the cell center. On the other hand, mitochondria microtubules and microfilaments display a distribution that closely resembles that observed in control cells. KHC suppression of neurons and astrocytes completely inhibited the Brefeldin A-induced spreading and tubulation of the Golgi-associated structure enriched in mannose-6-phosphate receptors. In addition, KHC suppression prevents the low pH-induced anterograde redistribution of late endocytic structures. Taken collectively, these observations suggest that in living neurons, kinesin mediates the anterograde transport of tubulovesicular structures originated in the central vacuolar system (e.g., the endoplasmic reticulum) and that the regulation of kinesin-membrane interactions may be of key importance for determining the intracellular distribution of selected organelles.

Molecular karyotype variation in Leishmania (Viannia) peruviana: indication of geographical populations in Peru distributed along a north-south cline

Forty-one Leishmania peruviana isolates were selected along a north-south transect which crossed areas endemic for uta in three different biogeographical regions in the Peruvian Andes. The isolates were analysed by molecular karyotyping and hybridization with three chromosome-derived DNA probes. All the isolates could be distinguished from L. braziliensis by their pLb-134 hybridization patterns. However, the patterns with the other probes (pLb-168 and -22) could be used to cluster the Peruvian isolates in discrete groups (karyodemes) which varied in their level of similarity with L. braziliensis. The geographical distribution of these karyodemes supports the hypothesis that eco-graphical isolation has contributed to the heterogeneity of L. peruviana.

Intraneuronal compartments of the amyloid precursor protein

The amyloid precursor protein (APP) is the parent molecule from which beta-amyloid protein is cleaved and deposits as amyloid fibrils in the senile plaques of Alzheimer's disease. Its primary structure resembles a receptor; however, no ligand has been identified. In growing hippocampal neurons APP is localized to growth cones. APP immunoreactivity was highly enriched in the axons of mature cultured neurons, where it appears as a specialization of the axonal membrane. Its anterograde translocation occurs via a kinesin-based motor. Following cytosolic acidification, APP colocalizes with late endosomes that get redistributed from the neuronal cell body to the processes. APP colocalizes in cultured hippocampal neurons to clathrin-immunoreactive clusters of vesicular-like structures. The finding lends additional credence to the possibility that APP could function as a receptor.

Suppression of MAP2 in cultured cerebellar macroneurons inhibits minor neurite formation

We show here that antisense MAP2 oligonucleotides inhibit neurite outgrowth in cultured cerebellar macroneurons. Unlike control neurons, which first extend a lamellipodial veil followed by a consolidation phase during which the cells extend minor neurites, MAP2-suppressed cells persist with lamellipodia and later become rounded. The induction of microtubules containing tyrosinated tubulin, which parallels neurite outgrowth in control neurons, was blocked under antisense conditions. The small but significant increase in acetylated microtubules was not affected. In contrast, the suppression of tau, which selectively blocks axonal elongation, completely prevented the increase of acetylated microtubules, but did not modify the induction of labile microtubules. These results suggest that MAP2 and tau have different functions: the initial establishment of neurites depends upon MAP2, whereas further neurite elongation depends upon tau and microtubule stabilization.

Expression of the class III beta-tubulin isotype in developing neurons in culture

The expression of the class III beta-tubulin isotype was studied in cultured brain neurons by means of a monoclonal antibody (TuJ1). The results obtained indicate that during early axonal outgrowth most of the class III beta-tubulin is not incorporated into microtubules, a phenomenon which is also observed under conditions which alter the rate and extent of the neurite outgrowth response. On the other hand, a dramatic increase in its incorporation into microtubules is observed after the neurons have differentiated their neurites as axons and dendrites. In addition, the appearance of colchicine-resistant microtubules containing this isotype, a phenomenon which occurs late in neurite development, is highly coincident with the appearance of stable microtubules containing high molecular weight microtubule-associated proteins (MAPs). This pattern is different from that of the accumulation and incorporation of other beta-tubulin isotypes into microtubules. Taken collectively, our results indicate that differences exist in the in vivo utilization of tubulin isotypes in developing brain neurons and suggest that the class III beta-tubulin isotype is not a primary factor involved in the regulation of microtubule assembly during early neurite outgrowth, but that it may be important for maintaining further neurite elongation and/or determining some unique binding property of MAPs to specific microtubule subsets.

The effect of tau antisense oligonucleotides on neurite formation of cultured cerebellar macroneurons

Tau, a microtubule-associated protein (MAP) enriched in axons, may have a role in the generation and maintenance of an axonal morphology. Neurons from embryonic day 15 rat cerebellum in culture elaborate two morphologically distinct neurite populations--one with nontapering, elongated axonlike neurites and the other with tapered dendritelike neurites that branch frequently and are selectively stained with antibodies to MAP2. Tau antisense oligonucleotides were utilized in two ways: (1) continuous application of antisense every 24 hr for variable periods of time or (2) application of antisense that was delayed until neurite differentiation was underway. In both cases, 24 hr after the administration of the antisense, tau protein was not detected immunocytochemically. When the antisense was given continuously directly after plating, the neurites persisted as simple minor outgrowths. When antisense was added 72 hr after plating, axonlike neurites were lost, while the remaining neurites continued to grow and increase in complexity. We concluded that the initial establishment of an elongated axonlike neurite is a prerequisite for further neurite maturation; however, once the axon is established, the remaining neurites are able to grow independently and assume a tapered dendritelike appearance.

Plants used in Guatemala for the treatment of respiratory diseases. 1. Screening of 68 plants against gram-positive bacteria

Respiratory ailments are important causes of morbidity and mortality in developing countries. Ethnobotanical surveys and literature reviews conducted in Guatemala during 1986-88 showed that 234 plants from 75 families, most of them of American origin, have been used for the treatment of respiratory ailments. Three Gram-positive bacteria causing respiratory infections (Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus pyogenes) were used to screen 68 of the most commonly used plants for activity. Twenty-eight of these (41.2%) inhibited the growth of one or more of the bacteria tested. Staphylococcus aureus was inhibited by 18 of the plant extracts, while 7 extracts were effective against Streptococcus pyogenes. Plants of American origin which exhibited antibacterial activity were: Gnaphalium viscosum, Lippia alba, Lippia dulcis, Physalis philadelphica, Satureja brownei, Solanum nigrescens and Tagetes lucida. These preliminary in vitro results provide scientific basis for the use of these plants against bacterial respiratory infections.

Estrogen-enhanced neurite growth: evidence for a selective induction of Tau and stable microtubules

Estrogen stimulates the neurite outgrowth response of medial basal hypothalamic neurons maintained in culture. We show here that one effect of estrogen is to promote an increase in tau, but not in tubulin, microtubule-associated protein 1a (MAP-1a), or MAP-2 protein levels. This response precedes and accompanies an increase in stable microtubules and in neurite length. Taken collectively, our data suggest that estrogen-enhanced neurite growth is mediated by a selective induction of microtubule-stabilizing factors, namely, the tau proteins.

Tau protein and the establishment of an axonal morphology

Dissociated neuronal cultures from several regions of the nervous system elaborate two populations of neurites which have features of axons and dendrites. The microtubule-associated protein tau appears to segregate to the axon in some of these culture systems, however it does not do so until after the development of morphological polarity. Despite this observation, tau very likely has some role in the development of polarity because in cultured cerebellar macroneurons taken from the rat embryonic day 15 primordial cerebellum, the inhibition of tau expression by antisense techniques resulted in the failure of a single minor neurite to elongate and form an axon-like neurite. Tau antisense given continuously for up to 72 h kept neurons locked in a stage with minor neurites only; however when released from the effects of the antisense they fully recovered. The administration of tau antisense after the development of polarity resulted in the loss of the axon-like neurite, while dendrite-like neurites continued to grow. Together these results suggest that dendritic differentiation in cerebellar macroneurons requires the prior elaboration of an axon-like structure.

Tyrosinated and detyrosinated microtubules in axonal processes of cerebellar macroneurons grown in culture

We have used the monoclonal antibody YL 1/2 (Tyr) specific for tyrosinated tubulin, and a polyclonal antibody (Glu) specific for detyrosinated tubulin to visualize the distribution of microtubules and microtubule assembly sites during axonal outgrowth. Cerebellar macroneurons growing in culture initially extend several short and thin neurites which have the potential to differentiate either as axons or dendrites (Ferreira and Caceres: Developmental Brain Research 49:205-213, 1989). At the onset of axonal outgrowth the Tyr antibody labels the minor neurites, the axon, and its growth cone, while the Glu antibody only shows immunoreactivity in the axonal shaft. After nocodazole treatment, the Tyr staining disappears, whereas that produced by the Glu antibody remains practically unchanged. When nocodazole was removed, tyrosinated microtubules reappeared first at the tip of the axon, in a more distal region than that occupied by detyrosinated microtubules; another focal site of tyrosinated tubulin incorporation was detected in the cell body. Incorporation of tyrosinated tubulin into growing axons was also studied after taxol treatment. After long incubation periods in the presence of taxol, the Tyr staining disappeared from the axon but remained in the cell body; however, immunoreactivity in this site was negative when the cells were preincubated in the presence of protein synthesis inhibitors. Release from taxol results in the reappearance of Tyr immunoreactivity at the distal end of the axon. Taken collectively, the present results indicate 1) that in cerebellar macroneurons axonal differentiation is accompanied by a temporal and spatial differentiation of microtubules and 2) that there is an active site of tyrosinated tubulin assembly at the tip of axonal processes, and they suggest that the highly tyrosinated domain in this region is a consequence of rapid microtubule turnover and tubulin tyrosine ligase activity.

Nerve growth factor potentiates the neurotoxicity of beta amyloid

The role of growth factors in the pathogenesis of Alzheimer disease is unknown. The beta-amyloid protein accumulates abnormally in the brain in Alzheimer disease and is neurotoxic to differentiated hippocampal neurons in culture. Nerve growth factor (NGF) increased the neurotoxic potency of a beta-amyloid polypeptide by a factor of approximately 100,000, which resulted in a reduction of the beta-amyloid neurotoxic EC50 from 0.1 microM to 1 pM. This potentiating effect of NGF was reversed by a monoclonal antibody against NGF and was not observed for a variety of other neurotrophic growth factors. Exposure of hippocampal neurons to very low concentrations of beta amyloid alone resulted in a marked induction of immunoreactive NGF receptors. Addition of NGF with beta amyloid resulted in the appearance of neurodegenerative changes in NGF receptor-positive neurons. The early and profound degeneration of hippocampal and basal forebrain cholinergic neurons that occurs in Alzheimer disease may result from a neurotoxic interaction of beta amyloid with NGF.

Coexpression of lactosyl and gangliotetraosyl gangliosides in rat cerebellar radial glial cells in culture

The expression of gangliosides of the lactosylceramide (LC) and of the gangliotetraosylceramide (GTC) series on the surface of cells from rat embryonic cerebellar tissue was investigated by double-color indirect immunofluorescence. GD3 was assumed to be representative of LC and was detected using a specific monoclonal antibody. GM1 was assumed to be representative of GTC and was detected using the binding of cholera toxin followed by the binding of cholera toxin antibodies. The expression of polysialosylated GTC (polysialosyl-GTC) was detected using the cholera toxin-cholera toxin antibody experimental approach after conversion of polysialosyl-GTC to GM1 by treatment of the cells with neuraminidase. To distinguish the major neural cell types present in the cultures the expression of the following cell type-specific markers was investigated: neuron-specific enolase and microtubule-associated protein-2 (MAP-2) as probes for neuronal cells and the intermediate filament protein glial fibrillar acidic protein (GFAP) as a probe for astroglial cells. More than 80% of cells dissociated from cerebellar tissue of 15-day-old rat embryos (E15) are positive for the expression of GD3 and about 50% for the expression of GM1 and polysialosyl-GTC, but most are negative for the expression of neuron-specific enolase, MAP-2, and GFAP. After culturing for 4 days (E15 + 4) most cells that show characteristics of neuronal cells are positive for the expression of polysialosyl-GTC and "inactivate" the expression of GD3. Most cells with characteristics of radial and stellate glial cells are also positive for the expression of polysialosyl-GTC, but unlike neuron-like cells, they do not "inactivate" the expression of GD3.

Inhibition of neurite polarity by tau antisense oligonucleotides in primary cerebellar neurons

Neurons in culture can have fundamentally distinct morphologies which permit their cytological identification and the recognition of their neurites as axons or dendrites. Microtubules may have a role in determining morphology by the selective stabilization of spatially distinct microtubule subsets. The plasticity of a neurite correlates inversely with the stability of its component microtubules: microtubules in growth cones are very dynamic, and in initial neurites there is continuous incorporation of labelled subunits, whereas in mature neurites, microtubules are highly stabilized. The binding of microtubule-associated proteins to the microtubules very probably contributes to this stability. Cerebellar neurons in dissociated culture initially extend exploratory neurites and, after a relatively constant interval, become polarized. Polarity becomes evident when a single neurite exceeds the others in length. These stable neurites cease to undergo the retractions and extensions characteristic of initial neurites and assume many features of axons and dendrites. We have now studied the role of the neuronal microtubule-associate protein tau in neurite polarization by selectively inhibiting tau expression by the addition of antisense oligonucleotides to the culture media. Although the extension of initial exploratory neurites occurred normally, neurite asymmetry was inhibited by the failure to elaborate an axon.

Ganglioside-enhanced neurite growth: evidence for a selective induction of high-molecular-weight MAP-2

Neuroblastoma cells maintained in serum-free medium exhibit a significant induction of MAP-1a and Tau proteins, but not MAP-2; the time course of these inductions is highly correlated with an increase in microtubule mass which parallels neurite growth. Bovine brain gangliosides (BBG) enhance the neurite outgrowth response of these cells. We report here that one effect of gangliosides is the selective and dramatic induction of MAP-2 expression. Our results also indicate a strong parallelism between this induction and the increase in microtubule mass which accompanies the appearance of more numerous, longer, and highly branched neurites. These observations suggest that MAP-2 induction in neuroblastoma cells may lead to a further differentiation of neurites equivalent to that observed in mature brain neurons. Finally, our results indicate that gangliosides per se are not neuritogenic factors but rather substances capable of enhancing cell-derived influences which affect the neurite outgrowth response of neuroblastoma cells and the type of MAP that they express.

Immunocytochemical localization of tubulin and the high molecular weight microtubule-associated protein 2 in Purkinje cell dendrites deprived of climbing fibers

The modifications in the localization of tubulin and the high molecular weight microtubule-associated protein 2 were studied in the cerebellum after partial denervation. Both proteins were localized in 40 micron sections using monoclonal antibodies against beta-tubulin (clones Tu9B and Tu12) or microtubule-associated protein 2 (clones AP9 and AP13), and polyclonal antisera against alpha- and beta-tubulin or microtubule-associated protein 2, visualized with the immunoperoxidase method of Sternberger [Sternberger (1979) Immunocytochemistry; Sternberger and Sternberger (1983) Proc. natn. Acad. Sci. U.S.A. 80 6126-6130] or a biotin-avidin system. The destruction of the inferior olive was performed in adult male rats by electrocoagulation or by intraperitoneal administration of 3-acetylpyridine. One day after chemical destruction of the inferior olive, anti-microtubule-associated protein 2 staining with either of the monoclonal antibodies or with the polyclonal antiserum was almost identical to that observed in the cerebellum of non-denervated animals. Specific staining was intense in the cell somata and dendrites and absent in myelinated tracts and in parallel fibers. However, 3 days after the lesion anti-microtubule-associated protein 2 staining showed a clear decrease, both in the proximal and the distal portions of thick secondary and tertiary dendritic trunks of the Purkinje cell. The intensity of the staining was also considerably reduced in the fine dendritic ramifications. By 8 days post-lesion, microtubule-associated protein 2 immunoreactivity began to increase, but only in the portions of the dendrites deprived of the climbing fibre; on the contrary, low immunoreactivity was found in the fine dendritic ramifications which are contacted by normal parallel fibers; microtubule-associated protein 2 immunoreactivity increased considerably by 11 days post-lesion, giving a pattern quite similar to that of non-denervated Purkinje cells. The alterations in microtubule-associated protein 2 immunoreactivity were also accompanied by a dramatic decrease in the immunostaining for tubulin, beginning on day-3 post-lesion and lasting until day-15 post-lesion. These changes were observed with either the monoclonal antibodies against beta-tubulin or with the polyclonal antiserum against alpha- and beta-tubulin. The changes in both molecules were also observed in animals in which the inferior olive was destroyed by electrocoagulation, ruling out the possibility of a direct action of 3-acetylpyridine on dendritic microtubular proteins.(ABSTRACT TRUNCATED AT 400 WORDS)

Heterogeneity of microtubule-associated protein 2 during rat brain development

The electrophoretic pattern of the large microtubule-associated protein, MAP2, changes during rat brain development. Immunoblots of NaDodSO4 extracts obtained from the cerebral cortex, cerebellum, and thalamus at 10-15 days after birth reveal only a single electrophoretic species when probed with any of three MAP2 monoclonal antibodies. By contrast, adult MAP2 contains two immunoreactive species, MAP2a and MAP2b. The single band of MAP2 from immature brain electrophoretically comigrates with adult MAP2b. Between postnatal days 17 and 18, immature MAP2 simultaneously resolves into two species in both the cerebellum and cerebral cortex. Immunoblots of NaDodSO4 extracts from spinal cord demonstrate the adult complement of MAP2 by day 10, indicating that MAP2 does not change coordinately throughout the entire central nervous system. In vitro cAMP-dependent phosphorylation of immature MAP2 causes a band split reminiscent of that seen during brain development in vivo. The possibility that the developmentally regulated changes observed in MAP2 during brain maturation are due to timed phosphorylation events is discussed.