Hyperglycemia alters N-glycans on colon cancer cells through increased production of activated monosaccharides.

Diabetes Mellitus (DM) is both, correlated and a known risk factor for colorectal cancer (CRC). Besides favoring the incidence of CRC, DM also accelerates its progression, worsening its prognosis. Previously, hyperglycemia, the DM hallmark, has been shown to lead to aberrant glycosylation of CRC cells, heightening their malignancy both in vivo and in vitro. Here we use mass spectrometry to elucidate the composition and putative structures of N-glycans expressed by MC38 cultured in normoglycemic (LG) and hyperglycemic-like conditions (HG). N-glycans, 67, were identified in MC38 cells cultured in LG and HG. The cells grown in HG showed a greater abundance of N-glycans when compared to LNG cells, without changes in the proportion of sialylated, fucosylated and mannosylated N-glycans. Among the identified N-glycans, 16 were differentially expressed, mostly mannosylated and fucosylated, with a minority of them being sialylated. Metabolomics analysis indicates that the alterations observed in the N-glycosylation may be mostly due to increase of the activated monosaccharides pool, through an increased glucose entrance into the cells. The alterations found here corroborate data from the literature regarding the progression of CRC, advocating for development or repositioning of effective treatments against CRC in diabetic patients.

Hyperglycemia exacerbates colon cancer malignancy through hexosamine biosynthetic pathway.

Hyperglycemia is a common feature of diabetes mellitus, considered as a risk factor for cancer. However, its direct effects in cancer cell behavior are relatively unexplored. Herein we show that high glucose concentration induces aberrant glycosylation, increased cell proliferation, invasion and tumor progression of colon cancer. By modulating the activity of the rate-limiting enzyme, glutamine-fructose-6-phosphate amidotransferase (GFAT), we demonstrate that hexosamine biosynthetic pathway (HBP) is involved in those processes. Biopsies from patients with colon carcinoma show increased levels of GFAT and consequently aberrant glycans' expression suggesting an increase of HBP flow in human colon cancer. All together, our results open the possibility that HBP links hyperglycemia, aberrant glycosylation and tumor malignancy, and suggest this pathway as a potential therapeutic target for colorectal cancer.

The genetic make-up of ovarian development and function: the focus on the transcription factor FOXL2.

In a 46 XY individual, the presence of the Y chromosome harboring the testis-determining factor (SRY) triggers testis determination and differentiation. In a 46 XX individual, the absence of SRY and the activation of genes associated with the female pathway lead to ovarian development. The latter process has long been considered as a default pathway. However, recent studies have cast doubts on this dogma. Here, after a brief overview of the main steps of ovarian development, we focus on three genes WNT4, RSPO1 and FOXL2 that are essential for ovarian determination, differentiation and/or maintenance. Special attention is paid to FOXL2 whose mutations are responsible for the blepharophimosis syndrome, often associated with female infertility, and for cancer. We highlight the cooperation of WNT4, RSPO1 and FOXL2 within a regulatory network and the need for further research to better understand their role in defining and maintaining ovarian identity.

Late-Onset Glycogen Storage Disease Type 2.

Glycogenosis II (GSDII) is an autosomal recessive lysosomal storage disorder resulting from acid alpha-glucosidase (GAA) deficiency, subsequent lysosomal accumulation of glycogen in muscles, impairment of autophagic processes and progressive cardiac, motor and respiratory failure. The infantile form usually appears in the first month of life, progresses rapidly and presents with severe cardiac involvement and complete deficiency of alpha-glucosidase activity (< 1% of normal controls). The late-onset form is characterized by great variability of the phenotypical spectrum. Main findings are muscle weakness and severe respiratory insufficiency while cardiac involvement may be completely absent. Residual GAA enzyme activity may correlate with severity of phenotype but many adult patients sharing the same mutations present with a wide variability in residual enzyme activity, age of onset and rate of disease progression, thus supporting a role for other factors, i.e., post-translational modifications and modifier genes, in modulating disease presentation. Enzyme replacement therapy (ERT) with alglucosidase alfa stabilizes the disease or improves muscle and/or respiratory function. However, efficacy of ERT may be influenced by several factors including age when ERT begins, extent of muscle damage, degree of defective autophagy, diversity in muscle fiber composition, difficulties in delivery of the therapeutic agent and antibody production. Further studies should be warranted to investigate factors determining the differences in clinical expression and therapeutic response in order to achieve better clinical and therapeutic management of these patients.

Role of the 9-O-acetyl GD3 in subventricular zone neuroblast migration.

In the mammalian central nervous system the subventricular zone (SVZ) is one of the few neurogenic regions that persist postnatally. Neuroblasts generated in the SVZ migrate from this region tangentially towards the olfactory bulbs via the rostral migratory stream (RMS) and give rise to interneurons. In previous studies, an important role in radial migration of cerebellar granule neurons has been attributed to the 9-O-acetylated GD3 ganglioside. Previous data demonstrated the expression of 9-O-acetyl GD3 in the rostral migratory stream in vivo as well as in chains of neuroblasts that migrate from SVZ explants in vitro. Herein, using the Jones monoclonal antibody (Jones mAb), we combined SVZ explant migration measurements and time-lapse videomicroscopy of migrating neuroblasts to show that SVZ neuroblast migration is inhibited by the antibody that recognizes 9-O-acetyl GD3 but not by A2B5, an antibody that recognizes c-series gangliosides. In addition, inhibition of ganglioside synthesis results in reduction of migratory halos around SVZ explants. Coherently, we show that most migratory neuroblasts which express the embryonic form of NCAM co-express 9acGD3. Also, we observe that some of the ganglioside positive neuroblasts also express nestin consistent with their maintained proliferative capacity. These results strongly support that the 9-O-acetyl GD3 has a pivotal role in neuroblast migration from SVZ, being fundamental for cell-cell and cell-substrate interactions in this region.

Aberrant Mid-Sagittal Fiber Tracts Visualized by Diffusion Tensor MR. A Case Report.

In hemimegalencephaly, MR imaging often reveals mid-sagittal band-like structures between the lateral ventricles. We describe the clinical presentation, morphologic abnormalities, conventional MR imaging, diffusion tensor MR and fiber tract (FT) reconstruction in a 14-year-old boy with unilateral hemimegalencephaly. We retrospectively examined MR images to determine whether these structures are aberrant mid-sagittal fibers.

Pseudotumoural Hemicerebellitis: Conventional MR Imaging and MR Spectroscopy Evolution. A Case Report.

Acute cerebellitis is an inflammatory process commonly involving both cerebellar hemispheres. Bilateral cerebellar hemispheres involvement is the most common finding. It typically occurs as a primary infectious, post-infectious or post-vaccination disorder, but is also a disease entity with heterogeneous pathogenesis including paraneoplasia. Acute cerebellitis is usually a benign, self-limiting and rarely fatal disease. Typically, cerebellar atrophy is a late consequence of the syndrome. We describe the radiological features of a case of pseudotumoural hemicerebellitis with emphasis on MRI and spectroscopy findings as non-invasive diagnostic tools to avoid unnecessary surgical procedures.

Early-onset dementia with prolonged occipital seizures: an atypical case of Kufs disease.

OBJECTIVE: Kufs disease is the adult-onset form of neuronal ceroid lipofuscinosis (NCL). Its two clinical phenotypes are type A (progressive myoclonus epilepsy with dementia) and type B (behavioral abnormalities and dementia, associated with pyramidal and extrapyramidal signs). METHODS: We describe the clinical evolution of an atypical case characterized by progressive dementia and focal occipital seizures. RESULTS: A healthy 37-year-old woman began showing memory deficits and behavioral disturbances (apathy, lack of inhibitions, untidiness). After 4 years, she developed rare clusters of tonic-clonic seizures, as well as focal seizures originating from the temporo-occipital regions, clinically associated with visual hallucinations, wandering, and agitation. When she was 44 years old, neuropsychological assessment revealed severe frontotemporal dementia. MRI showed cortical atrophy and, on T2-weighted images, hypointensity of the basal ganglia, and hyperintensity and reduction of the deep white matter. On the basis of these findings, a diagnosis of Kufs disease was hypothesized. A skin biopsy was negative, but electron microscopy examination of a right frontal lobe brain biopsy revealed the presence of typical storage material (fingerprint inclusions). The patient never developed myoclonus or extrapyramidal signs. DISCUSSION: Kufs disease is difficult to diagnose on account of its heterogeneous clinical pattern and pathologic features, and the lack of a specific genetic locus alteration. The neuropsychological pattern and MRI findings observed in patients with early-onset frontotemporal dementia and seizure disorder suggest that Kufs disease should be considered in their differential diagnosis. Extracerebral biopsy can be nondiagnostic, and when alternative diagnoses have been ruled out, cerebral biopsy should be considered.

Bilateral trigeminal enhancement on magnetic resonance imaging in a patient with multiple sclerosis and trigeminal neuralgia.

We report on clinical and instrumental findings of a multiple sclerosis (MS) patient with sudden right trigeminal neuralgia (TN). Magnetic resonance imaging (MRI), performed at TN onset, showed enlargement of both trigeminal nerves (TrN) at the root entry zone, with gadolinium enhancement of the cisternal portion. This is the first description of clinical and MRI findings indicative of peripheral involvement of the fifth cranial nerve in a MS patient complaining of TN. Our report shows the concomitant involvement of central and peripheral myelin in MS, and adds further highlights to the question regarding peripheral nerve involvement abnormalities associated with a disease considered limited to the central nervous system (CNS).

Postinfectious inflammatory disorders: subgroups based on prospective follow-up.

BACKGROUND: Acute disseminated encephalomyelitis (ADEM) refers to a monophasic acute multifocal inflammatory CNS disease. However, both relapsing and site-restricted variants, possibly associated with peripheral nervous system (PNS) involvement, are also observed, and a systematic classification is lacking. OBJECTIVE: To describe a cohort of postinfectious ADEM patients, to propose a classification based on clinical and instrumental features, and to identify subgroups of patients with different prognostic factors. METHODS: Inpatients of a Neurologic and Infectious Disease Clinic affected by postinfectious CNS syndrome consecutively admitted over 5 years were studied. RESULTS: Of 75 patients enrolled, 60 fulfilled criteria for ADEM after follow-up lasting from 24 months to 7 years. Based on lesion distribution, patients were classified as encephalitis (20%), myelitis (23.3%), encephalomyelitis (13.3%), encephalomyeloradiculoneuritis (26.7%), and myeloradiculoneuritis (16.7%). Thirty patients (50%) had a favorable outcome. Fifteen patients (25%) showed a relapsing course. Poor outcome was related with older age at onset, female gender, elevated CSF proteins, and spinal cord and PNS involvement. All but two patients received high-dose steroids as first-line treatment, with a positive response in 39 (67%). Ten of 19 nonresponders (53%) benefited from high-dose IV immunoglobulin; 9 of 10 had PNS involvement. The data were not controlled. CONCLUSIONS: A high prevalence of "atypical variants" was found in this series, with site-restricted damage or additional peripheral nervous system (PNS) involvement. Prognosis and response to steroids were generally good, except for some patient subgroups. In patients with PNS involvement and steroid failure, a favorable effect of IV immunoglobulin was observed.

Happy together: the life and times of Ty retrotransposons and their hosts.

The aim of this review is to describe the level of intimacy between Ty retrotransposons (Ty1-Ty5) and their host the yeast Saccharomyces cerevisiae. The effects of Ty location in the genome and of host proteins on the expression and mobility of Ty elements are highlighted. After a brief overview of Ty diversity and evolution, we describe the factors that dictate Ty target-site preference and the impact of targeting on Ty and adjacent gene expression. Studies on Ty3 and Ty5 have been especially informative in unraveling the role of host factors (Pol III machinery and silencing proteins, respectively) and integrase in controlling the specificity of integration. In contrast, not much is known regarding Ty1, Ty2 and Ty4, except that their insertion depends on the transcriptional competence of the adjacent Pol III gene and might be influenced by some chromatin components. This review also brings together recent findings on the regulation of Ty1 retrotransposition. A large number of host proteins (over 30) involved in a wide range of cellular processes controls either directly or indirectly Ty1 mobility, primarily at post-transcriptional steps. We focus on several genes for which more detailed analyses have permitted the elaboration of regulatory models. In addition, this review describes new data revealing that repression of Ty1 mobility also involves two forms of copy number control that act at both the trancriptional and post-transcriptional levels. Since S. cerevisiae lacks the conserved pathways for copy number control via transcriptional and post-transcriptional gene silencing found in other eukaryotes, Ty1 copy number control must be via another mechanism whose features are outlined. Ty1 response to stress also implicates activation at both transcriptional and postranscriptional steps of Ty1. Finally, we provide several insights in the role of Ty elements in chromosome evolution and yeast adaptation and discuss the factors that might limit Ty ectopic recombination.

Acute and topic anti-edematogenic fractions isolated from the seeds of Pterodon pubescens.

We previously demonstrated that alcoholic extracts from Pterodon pubescens Benth. (Sucupira branca, Leguminosae) seeds exhibit anti-arthritic activity. In the present work we show that the oleaginous extract obtained from P. pubescens seeds (OEP) exhibits acute or topic anti-edematogenic activity when tested in carrageenan-induced paw edema or in croton oil-induced ear edema assays, respectively. Four fractions were obtained from OEP by sequential liquid-liquid extraction. The anti-edematogenic properties were predominant in the hexanic fraction, which was further fractionated by HPLC, yielding three sub-fractions (PF1.1, PF1.2 and PF1.3). PF1.1 and PF1.3 showed potent acute and topic anti-edematogenic activity. The PF1.2 sub-fraction, although not active in the carrageenan assay, exhibited a potent anti-edematogenic activity in the croton oil-induced ear edema. This sub-fraction shows a maximum efficacy similar to indometacin in a lower dose. The PF1.1 sub-fraction presented a complex mixture containing furane diterpene derivatives of vouacapan. PF1.2 consists of a single substance, geranylgeraniol, as determined by GC/MS and NMR, while PF1.3 contains farnesol.

Characterization of novel structures of mannosylinositolphosphorylceramides from the yeast forms of Sporothrix schenckii.

Novel structures of glycoinositolphosphorylceramide (GIPC) from the infective yeast form of Sporothrix schenckii were determined by methylation analysis, mass spectrometry and NMR spectroscopy. The lipid portion was characterized as a ceramide composed of C-18 phytosphingosine N-acylated by either 2-hydroxylignoceric acid (80%), lignoceric (15%) or 2,3-dihydroxylignoceric acids (5%). The ceramide was linked through a phosphodiester to myo-inositol (Ins) which is substituted on position O-6 by an oligomannose chain. GIPC-derived Ins oligomannosides were liberated by ammonolysis and characterized as: Manpalpha1-->6Ins; Manpalpha1-->3Manpalpha1-->6Ins; Manpalpha1-->6Manpalpha1-->3Manpalpha1-->3Manpalpha1-->6Ins; Manpalpha1-->2Manpalpha1-->6Manpalpha1-->3Manpalpha1-->3Manpalpha1-->6Ins. These structures comprise a novel family of fungal GIPC, as they contain the Manpalpha1-->6Ins substructure, which has not previously been characterized unambigously, and may be acylated with a 2,3 dihydroxylignoceric fatty acid, a feature hitherto undescribed in fungal lipids.

Structure of O-glycosidically linked oligosaccharides from glycoproteins of Trypanosoma cruzi CL-Brener strain: evidence for the presence of O-linked sialyl-oligosaccharides.

Glycoproteins on the cell surface of Trypanosoma cruzi are known to play important roles in the interaction of the parasite with the host cells. We previously determined the structures of the O-glycan chains from the sialoglycoproteins (mucin-like molecules) of the G- and Y-strains and observed significant differences between them. We now report the structures of the sialylated and nonsialylated O-linked oligosaccharides isolated from the cell surface glycoproteins of the myotropic CL-Brener strain grown in the presence of fetal calf serum. The structures of the O-linked oligosaccharide alditols obtained by reductive beta-elimination of the sialoglycoprotein were determined by a combination of methylation analysis, fast atom bombardment-mass spectrometry and nuclear magnetic resonance spectroscopy. The presence of a beta-galactopyranose substituent on the N-acetylglucosamine O-4 position shows that these O-linked oligosaccharides from CL-Brener strain belong to the same family as those isolated from mucins expressed by T. cruzi Y strain, a reticulotropic strain. In addition, novel O-glycans, including alpha2-3 mono-sialylated species are described.

Trans-sialidase from Trypanosoma cruzi catalyzes sialoside hydrolysis with retention of configuration.

The trans -sialidase from Trypanosoma cruzi is a member of the sialidase superfamily that functions as a sialidase in the absence of a carbohydrate acceptor. We have used(1)H nuclear magnetic resonance (NMR) spectroscopy to investigate the stereospecificity of the hydrolysis of two substrates, namely, 4-methyl-umbelliferyl- N -acetylneur-aminic acid and alpha(2-3)-sialyllactose, catalyzed by a recombinant T.cruzi trans -sialidase. We demonstrate that, in aqueous solution, the thermodynamically less stable alpha-form of N -acetylneuraminic acid is the initial product of the hydrolysis; subsequent mutarotation leads eventually to an equilibrium mixture of the alpha and beta forms, in molar ratio 8:92. In a mixed water/methanol solution, the hydrolysis reaction produces also the alpha-methyl sialoside but not its beta-methyl counterpart. We also show that 4-methyl-umbelliferyl- N -acetylneuraminic acid is a significantly better substrate for the sialidase than alpha(2-3)-sialyllactose. Prolonged incubation of alpha(2-3)-sialyllactose with an excess of trans -sialidase produced a trace of 2-deoxy-2,3-didehydro- N -acetylneuraminic acid, as identified by NMR spectroscopy and by gas liquid chromatography/mass spectro-metry. In conclusion, this study shows that the stereo-selectivity of the sialidase activity of T.cruzi trans -sialidase is identical to that of bacterial, viral, and mammalian sialidases, suggesting a similar active-site architecture.

2-Pyridylarylhydrazone derivatives, a new class of platelet aggregation inhibitors.

A series of 2-pyridylarylhydrazone derivatives was synthesized and compared with a previously reported pyrazole series, i.e., 4-acylpyrazolylarylhydrazone and 5-pyrazolylarylhydrazone, which present antiplatelet aggregation activity. The structures of these pyridylarylhydrazone derivatives were designed on the basis of the known bioisosteric relationship of the heteroaromatic ring. The antiplatelet aggregation activity was measured in vitro on citrated platelet-rich rabbit plasma in which aggregation was induced with 5 microM ADP, 5 micrograms/ml collagen and 200 microM arachidonic acid. Eighteen compounds belonging to the pyridine series were tested at 1 mM concentration and none inhibited ADP-induced rabbit platelet aggregation. 2-(2-Formylfurane)pyridylhydrazone exhibited a highly potent inhibitory activity on arachidonic acid-induced aggregation, with an IC50 of 0.35 microM. These results suggest that the hydrazone unit and the 2-furyl moiety of the arylhydrazone framework are important pharmacophores for antiplatelet activity.

2-pyridylarylhydrazone derivatives, a new class of platelet aggregation inhibitors

A series of 2-pyridylarylhydrazone derivatives was synthesized and compared with a previously reported pyrazole series, i.e., 4-acylpyrazolylarylhydrazone and 5-pyrazolylarylhydrazone, which present antiplatelet aggregation activity. The structures of these pyridylarylhydrazone derivatives were designed on the basis of the known bioisosteric relationship of the heteroaromatic ring. The antiplatelet aggregation activity was measured in vitro on citrated platelet-rich rabbit plasma in which aggregation was induced with 5 muM ADP, 5 mug/ml collagen and 200 muM arachidonic acid. Eighteen compounds belonging to the pyridine series were tested at 1 mM concentration and none inhibited ADP-induced rabbit platelet aggregation. 2-(2-Formylfurane)pyridylhydrazone exhibited a highly potent inhibitory activity on arachidonic acid-induced aggregation, with an IC50 of 0.35 muM. These results suggest that the hydrazone unit and the 2-furyl moiety of the arylhydrazone framework are important pharmacophores for antiplatelet activity.