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1.
Front Pharmacol ; 13: 905711, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36034826

RESUMEN

Sociability is an essential component of the linkage structure in human and other vertebrate communication. Low sociability is defined as a poor social approach, including social withdrawal and apathy, and is implicated in a variety of psychiatric disorders. Ninjinyoeito (NYT), a traditional Japanese herbal medicine, has been used in the medical field. This study aimed to determine the effect of NYT on low sociality in NPY-KO zebrafish. NPY-KO zebrafish were fed a 3% NYT-supplemented diet for 4 days and subjected to behavioral tests. In the mirror test, NPY-KO zebrafish fed a control diet showed avoidance behavior toward their mirror counterparts. In contrast, the treatment of NPY-KO zebrafish with NYT significantly increased their interaction with their counterparts in the mirror. In addition, a 3-chambers test was conducted to confirm the effect of NYT on the low sociality of NPY-KO zebrafish. NPY-KO zebrafish fed the control diet showed less interaction with fish chambers, while NYT treatment increased the interaction. Phosphorylation of ERK, a marker of neuronal activity, was significantly reduced in the whole brain of NYT-fed NPY-KO zebrafish, compared to the control diet. NYT treatment significantly suppressed hypothalamic-pituitary-adrenal-related genes (gr, pomc, and crh) and sympathetic-adrenal-medullary-related genes (th1, th2, and cck) in NPY-KO zebrafish. NYT administration significantly reduced mRNA levels of gad1b compared to the control diet, suggesting the involvement of GABAergic neurons in NYT-induced improvement of low sociability. Furthermore, the expression of CREB was suppressed when NPY-KO zebrafish were fed NYT. Next, we attempted to identify the effective herb responsible for the NYT-induced improvement of low sociability. NPY-KO zebrafish were fed an experimental diet containing the target herb for 4 days, and its effect on sociability was evaluated using the 3-chambers test. Results showed that Cinnamon Bark and Polygala Root treatments significantly increased time spent in the fish tank area compared to the control diet, while the other 10 herbs did not. We confirmed that these two herbs suppressed the activity of HPA-, SAM-, and GABAergic neurons, as well as NYT-treated zebrafish, accompanied by downregulation of CREB signaling. This study suggests the potential use of NYT as a drug for sociability disorders.

2.
Glycoconj J ; 39(4): 499-512, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35877057

RESUMEN

Neu1 is a glycosidase that releases sialic acids from the non-reducing ends of glycoconjugates, and its enzymatic properties are conserved among vertebrates. Recently, Neu1-KO zebrafish were generated using genome editing technology, and the KO fish showed abnormal emotional behavior, such as low schooling, low aggressiveness, and excess exploratory behavior, accompanied by the downregulation of anxiety-related genes. To examine the alteration of neuronal and glial cells in Neu1-KO zebrafish, we analyzed the molecular profiles in the zebrafish brain, focusing on the midbrain and telencephalon. Using immunohistochemistry, we found that signals of Maackia amurensis (MAM) lectin that recognizes Sia α2-3 linked glycoconjugates were highly increased in Neu1-KO zebrafish brains, accompanied by an increase in Lamp1a. Neu1-KO zebrafish suppressed the gene expression of AMPA-type glutamate receptors such as gria1a, gria2a, and gria3b, and vesicular glutamate transporter 1. Additionally, Neu1-KO zebrafish induced the hyperactivation of astrocytes accompanied by an increase in Gfap and phosphorylated ERK levels, while the mRNA levels of astrocyte glutamate transporters (eaat1a, eaat1c, and eaat2) were downregulated. The mRNA levels of sypb and ho1b, which are markers of synaptic plasticity, were also suppressed by Neu1 deficiency. Abnormal activity of microglia was also revealed by IHC, and the expressions of iNOS and IL-1ß, an inflammatory cytokine, were increased in Neu1-KO zebrafish. Furthermore, drastic neuronal degeneration was detected in Neu1-KO zebrafish using Fluoro-Jade B staining. Collectively, the neuronal and glial abnormalities in Neu1-KO zebrafish may be caused by changes in the excitatory neurotransmitter glutamate and involved in the emotional abnormalities.


Asunto(s)
Neuraminidasa , Pez Cebra , Animales , Glutamatos , Glicoconjugados , Neuraminidasa/genética , Neuroglía/metabolismo , ARN Mensajero/metabolismo , Pez Cebra/genética
3.
Gene ; 836: 146667, 2022 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-35714800

RESUMEN

Neu1 is a lysosomal glycosidase that catalyzes the removal of sialic acids from glycoconjugates. Although Neu1 sialidase is highly conserved among vertebrates, the role of fish Neu1 is not fully understood because of its unique aquatic living situation. Compared to land animals, fish have a higher chance of bacterial infection, and to understand the role of fish Neu1, the susceptibility of Neu1 knockout zebrafish (Neu1-KO) was evaluated using Edwardsiella piscicida, a fish pathogen. Neu1-KO larvae showed high susceptibility to E. piscicida, despite the activation of macrophages, and presented increased lysosomal signals induced by the accumulation of Sia α2-3 linked oligosaccharides. The accumulation coincided with the signal of the macrophage marker, suggesting that the dysfunction of lysosomes in macrophages would result in a high susceptibility of Neu1-KO to E. piscicida. Chloroquine, an inhibitor of lysosomal degradation, induced high mortality of wild type zebrafish with E. piscicida infection accompanied by increased lysosomal accumulation, similar to Neu1-KO zebrafish. This study revealed that Neu1 sialidase plays a crucial role in the lysosomal degradation of macrophages with a bacterial infection.


Asunto(s)
Neuraminidasa , Pez Cebra , Animales , Edwardsiella , Lisosomas , Mucolipidosis , Neuraminidasa/genética , Neuraminidasa/metabolismo , Pez Cebra/genética , Pez Cebra/metabolismo
4.
J Obstet Gynaecol Res ; 47(11): 4093-4100, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34378271

RESUMEN

Lymphoepithelioma-like carcinoma of the uterine cervix is a rare variant of squamous cell carcinoma. Herein, we describe three cases of lymphoepithelioma-like carcinoma of the uterine cervix and review relevant literature. All three patients initially presented with postmenopausal bleeding. Gross appearances were endophytic with ulcerated mucosa in case 1, exophytic with polypoid morphology in case 2, and unremarkable even using colposcopy and hysteroscopy in case 3. Magnetic resonance imaging demonstrated well-demarcated cervical masses with high-intermediate intensity on T2-weighted images and high intensity on diffusion-weighted images in all three cases. In case 3, biopsy referring to local information from magnetic resonance images was required for preoperative diagnosis. We reviewed the literature of 59 lymphoepithelioma-like carcinoma cases in 19 papers published between 2001 and 2020. Preoperative diagnosis of lymphoepithelioma-like carcinoma is sometimes challenging, although magnetic resonance imaging findings may help determine the location of the tumor and obtain a successful biopsy.


Asunto(s)
Carcinoma de Células Escamosas , Neoplasias del Cuello Uterino , Biopsia , Cuello del Útero/diagnóstico por imagen , Cuello del Útero/cirugía , Femenino , Humanos , Imagen por Resonancia Magnética , Neoplasias del Cuello Uterino/diagnóstico por imagen , Neoplasias del Cuello Uterino/cirugía
5.
Sci Rep ; 11(1): 13477, 2021 06 29.
Artículo en Inglés | MEDLINE | ID: mdl-34188220

RESUMEN

NEU1 sialidase hydrolyzes sialic acids from glycoconjugates in lysosomes. Deficiency of NEU1 causes sialidosis with symptoms including facial dysmorphism, bone dysplasia, and neurodegeneration. However, the effects of NEU1 deficiency on emotional activity have not been explored. Here, we conducted the behavioral analysis using Neu1-knockout zebrafish (Neu1-KO). Neu1-KO zebrafish showed normal swimming similar to wild-type zebrafish (WT), whereas shoaling was decreased and accompanied by greater inter-fish distance than WT zebrafish. The aggression test showed a reduced aggressive behavior in Neu1-KO zebrafish than in WT zebrafish. In the mirror and 3-chambers test, Neu1-KO zebrafish showed more interest toward the opponent in the mirror and multiple unfamiliar zebrafish, respectively, than WT zebrafish. Furthermore, Neu1-KO zebrafish also showed increased interaction with different fish species, whereas WT zebrafish avoided them. In the black-white preference test, Neu1-KO zebrafish showed an abnormal preference for the white region, whereas WT zebrafish preferred the black region. Neu1-KO zebrafish were characterized by a downregulation of the anxiety-related genes of the hypothalamic-pituitary-adrenal axis and upregulation of lamp1a, an activator of lysosomal exocytosis, with their brains accumulating several sphingoglycolipids. This study revealed that Neu1 deficiency caused abnormal emotional behavior in zebrafish, possibly due to neuronal dysfunction induced by lysosomal exocytosis.


Asunto(s)
Conducta Animal , Emociones , Neuraminidasa/deficiencia , Conducta Social , Proteínas de Pez Cebra/deficiencia , Pez Cebra , Animales , Técnicas de Inactivación de Genes , Neuraminidasa/metabolismo , Proteínas de Pez Cebra/metabolismo
6.
Obstet Gynecol Sci ; 63(6): 709-718, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32937685

RESUMEN

OBJECTIVE: The need for tailoring ovarian cancer treatments to individual patients is increasing. This study aimed to evaluate the prognostic value of pretreatment laboratory test data for predicting the response and survival outcomes of platinumbased chemotherapy in ovarian cancer. METHODS: We enrolled 270 patients with ovarian cancer diagnosed at the Kyoto Medical Center (n=120; group A) and Kyoto University (n=150; group B). Data on 9 blood parameters (neutrophil to lymphocyte ratio [NLR], platelet to lymphocyte rate [PLR], C-reactive protein, lactate dehydrogenase [LDH], glucose, total cholesterol, high-density lipoprotein [HDL], low-density lipoprotein, and triglyceride levels), cancer pathology, cancer stage, cytoreduction outcomes, serum cancer antigen 125 levels, platinum-free interval (PFI), disease-free survival (DFS), and overall survival were assessed retrospectively. RESULTS: NLR, PLR, LDH, and HDL were significantly different in advanced stage patients (P<0.001, <0.001, 0.029, and <0.001, respectively). The Kaplan-Meier curves revealed that high LDH level (≥250 U/L) was associated with reduced PFI (P=0.037 and 0.012) and DFS (P=0.007 and 0.002) in groups A and B, respectively. High NLR (≥4) was associated with reduced DFS in both groups (P=0.036 and 0.005, respectively). LDH showed higher area under the curve (AUC) values in predicting platinum resistance with a PFI of less than 6 months and 12 months (AUC=0.606 and 0.646, respectively) than NLR. In the multivariate analysis, LDH remained significant (P=0.019) after adjusting for the 9 blood parameters. CONCLUSION: Serum LDH level may possibly predict platinum resistance and prognosis in ovarian cancer and may be useful when developing precision medicine for individual patients.

7.
Biochem J ; 477(15): 2841-2857, 2020 08 14.
Artículo en Inglés | MEDLINE | ID: mdl-32686823

RESUMEN

Mammalian sialidase Neu1 is involved in various physiological functions, including cell adhesion, differentiation, cancer metastasis, and diabetes through lysosomal catabolism and desialylation of glycoproteins at the plasma membrane. Various animal models have been established to further explore the functions of vertebrate Neu1. The present study focused on zebrafish (Danio rerio) belonging to Cypriniformes as an experimental animal model with neu1 gene deficiency. The results revealed that the zebrafish Neu1 desialyzed both α2-3 and α2-6 sialic acid linkages from oligosaccharides and glycoproteins at pH 4.5, and it is highly conserved with other fish species and mammalian Neu1. Furthermore, Neu1-knockout zebrafish (Neu1-KO) was established through CRISPR/Cas9 genome editing. Neu1-KO fish exhibited slight abnormal embryogenesis with the accumulation of pleural effusion; however, no embryonic lethality was observed. Although Neu1-KO fish were able to be maintained as homozygous, they showed smaller body length and weight than the wild-type (WT) fish, and muscle atrophy and curvature of the vertebra were observed in adult Neu1-KO fish (8 months). The expression patterns of myod and myog transcription factors regulating muscle differentiation varied between Neu1-KO and WT fish embryo. Expression of lysosomal-related genes, including ctsa, lamp1a, and tfeb were up-regulated in adult Neu1-KO muscle as compared with WT. Furthermore, the expression pattern of genes involved in bone remodeling (runx2a, runx2b, and mmp9) was decreased in Neu1-KO fish. These phenotypes were quite similar to those of Neu1-KO mice and human sialidosis patients, indicating the effectiveness of the established Neu1-KO zebrafish for the study of vertebrate Neu1 sialidase.


Asunto(s)
Neuraminidasa/genética , Neuraminidasa/metabolismo , Proteínas de Pez Cebra/genética , Pez Cebra/genética , Animales , Animales Modificados Genéticamente , Peso Corporal/genética , Sistemas CRISPR-Cas , Modelos Animales de Enfermedad , Embrión no Mamífero , Femenino , Regulación del Desarrollo de la Expresión Génica , Técnicas de Inactivación de Genes , Glicoproteínas/genética , Glicoproteínas/metabolismo , Células HEK293 , Humanos , Concentración de Iones de Hidrógeno , Masculino , Mucolipidosis/etiología , Mucolipidosis/genética , Ácido N-Acetilneuramínico/metabolismo , Osteogénesis/genética , Fenotipo , Pez Cebra/embriología , Proteínas de Pez Cebra/metabolismo
8.
J Matern Fetal Neonatal Med ; 33(19): 3286-3292, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30651015

RESUMEN

Background: Uterine atony is the leading cause of severe postpartum hemorrhage (PPH); however, the underlying cause of intractable atonic PPH unresponsive to conventional treatments (such as uterotonics and intrauterine balloon tamponade) remains unclear.Objectives: The aim of this study was to investigate whether intractable atonic PPH is associated with the type of bleeding (arterial or nonarterial) and its location, along with variations in the size and shape of the uterine cavity after delivery.Study design: This retrospective study included women who had undergone a dynamic computed tomography (CT) scan for the management of severe PPH at Kyoto University Hospital between April 2011 and March 2017. Patients' electronic medical records were reviewed, and relevant clinical information was collected. The presence of contrast extravasation (CE) on CT images in the early phase (40 s) was regarded as active arterial bleeding. Bleeding sites and size of the uterine cavity were evaluated using an xyz coordinate system. The size of the uterine cavity was compared between groups with CE into the upper and lower parts of the uterine body.Results: Of the 60 women assessed for eligibility, 30 were included in the current analysis. Contrast extravasation was detected in 19 women, with 14 showing CE in the early phase. The presence of CE in the early phase was significantly associated with the need for transarterial embolization (Fisher's exact test, p = .0017). The upper and lower parts of the uterine cavity were 97.4 ± 2.7 mm (mean ± standard error of the mean) and 87.2 ± 3.5 mm in length, respectively. The maximum anteroposterior diameters of the upper and lower parts of the uterine cavity were 23.1 ± 2.6 and 76.0 ± 3.0 mm, respectively, and the largest transverse diameters were 67.3 ± 1.9 and 81.1 ± 2.3 mm, respectively. The group that showed CE into the upper uterine cavity had significantly larger qualitative parameters of the upper uterine cavity compared to the group with CE into the lower uterine cavity. The gate from the lower uterine cavity toward the upper uterine cavity was narrow (anteroposterior diameter of 22.6 ± 2.0 mm, transverse diameter of 40.7 ± 3.3 mm), and the intrauterine balloon was always found in the lower uterine cavity on the CT scan. The upper uterine body was characterized by a flat oval-shaped cavity (xy plane), thick uterine wall, and lack of uniformity among bleeding sites (z = 62.4 ± 14.8 mm). In contrast, the lower uterine cavity was a circular shape (xy plane) with thin walls, and bleeding sites were located at lateral sides around the level of the internal os (z = -18.8 ± 4.9 mm).Conclusions: Atonic PPH has a significant subtype, named "PRACE," which is characterized by PPH, resistance to treatment, and arterial CE. The need for embolization can be predicted by the presence of arterial bleeding and its location, along with the shape of the uterine cavity.


Asunto(s)
Hemorragia Posparto , Taponamiento Uterino con Balón , Inercia Uterina , Femenino , Humanos , Hemorragia Posparto/diagnóstico por imagen , Hemorragia Posparto/terapia , Embarazo , Estudios Retrospectivos , Tomografía Computarizada por Rayos X , Resultado del Tratamiento , Inercia Uterina/diagnóstico por imagen , Inercia Uterina/terapia
9.
Eur J Pharmacol ; 782: 21-9, 2016 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-27105818

RESUMEN

Naringin, which is one of the flavonoids contained in citrus fruits, is well known to possess various healthy functions to humans. It has been reported that naringin suppresses cancer cell growth in vitro and in vivo, although the underlying mechanisms are not fully understood. Recently, the roles of glycoconjugates, such as gangliosides, in cancer cells have been focused because of their regulatory effects of malignant phenotypes. Here, to clarify the roles of naringin in the negative-regulation of cancer cell growth, the alteration of glycoconjugates induced by naringin exposure and its significance on cell signaling were investigated. Human cancer cells, HeLa and A549, were exposed to various concentrations of naringin. Naringin treatment induced the suppression of cell growth toward HeLa and A549 cells accompanied with an increase of apoptotic cells. In naringin-exposed cells, GM3 ganglioside was drastically increased compared to the GM3 content prior to the treatment. Furthermore, naringin inhibited NEU3 sialidase, a GM3 degrading glycosidase. Similarly, NEU3 inhibition activities were also detected by other flavanone, such as hesperidin and neohesperidin dihydrocalcone, but their aglycones showed less inhibitions. Naringin-treated cancer cells showed suppressed EGFR and ERK phosphorylation levels. These results suggest a novel mechanism of naringin in the suppression of cancer cell growth through the alteration of glycolipids. NEU3 inhibitory effect of naringin induced GM3 accumulation in HeLa and A549 cells, leading the attenuation of EGFR/ERK signaling accompanied with a decrease in cell growth.


Asunto(s)
Receptores ErbB/metabolismo , Flavanonas/farmacología , Gangliósido G(M3)/metabolismo , Inhibidores de Glicósido Hidrolasas/farmacología , Neuraminidasa/antagonistas & inhibidores , Transducción de Señal/efectos de los fármacos , Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Glicoconjugados/metabolismo , Células HeLa , Humanos , Fosforilación/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacos
10.
Gene ; 575(2 Pt 2): 513-523, 2016 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-26432003

RESUMEN

Desialylation in the lysosome is a crucial step for glycoprotein degradation. The abnormality of lysosomal desialylation by NEU1 sialidase is involved in diseases of mammals such as sialidosis and galactosialidosis. Mammalian Neu1 sialidase is also localized at plasma membrane where it regulates several signaling pathways through glycoprotein desialylation. In fish, on the other hand, the mechanism of desialylation in the lysosome and functions of Neu1 sialidase are still unclear. Here, to understand the significance of fish Neu1 sialidase, neu1 gene was cloned from medaka brain and the profiles of its polypeptides were analyzed. Open reading frame of medaka neu1 consisted 1,182 bp and the similarity of its deduced amino acids with human NEU1 was 57%. As this recombinant polypeptide did not show significant sialidase activity, medaka cathepsin A, known in mammals as protective protein activating Neu1, was cloned and then co-expressed with medaka Neu1 to examine whether medaka cathepsin A activates Neu1 activity. As a result, Neu1/cathepsin A showed a drastic increase of sialidase activity toward MU-NANA. Major substrate of medaka Neu1 was 3-sialyllactose and its optimal pH was 4.0. With immunofluorescence analysis, signal of overexpressed medaka Neu1 was found to coincide with Lysotracker signals (organelle marker of lysosome) and co-localized with medaka cathepsin A in fish hepatic Hepa-T1 cells. Furthermore, part of medaka Neu1 was also detected at plasma membrane. Medaka Neu1 possessed signal peptide sequence at N-terminal and incomplete lysosomal targeting sequence at C-terminus. Medaka neu1 gene was ubiquitously expressed in various medaka tissues, and its expression level was significantly higher than other sialidase genes such as neu3a, neu3b and neu4. The present study revealed the profiles of fish Neu1 sialidase and indicated its high conservation with human NEU1 for the first time, suggesting the presence of similar desialylation system in the medaka lysosome to human. Moreover, the present study showed the possibility of medaka as a model animal of human NEU1 sialidase.


Asunto(s)
Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Lisosomas/enzimología , Neuraminidasa/genética , Neuraminidasa/metabolismo , Oryzias/genética , Animales , Secuencia de Bases , Encéfalo/metabolismo , Línea Celular , Clonación Molecular , Secuencia Conservada , Células HEK293 , Humanos , Oryzias/metabolismo , Especificidad por Sustrato
11.
Fish Physiol Biochem ; 40(5): 1461-72, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24744226

RESUMEN

Glycoconjugates are known to be involved in many physiological events in vertebrates. Sialidase is one of the glycosidases, which removes sialic acid from glycoconjugates. In mammals, the properties and physiological functions of sialidases have been investigated, while there is little understanding of fish sialidase. Here, to investigate the significance of fish neu4 sialidase, neu4 gene was cloned from medaka brain mRNA and identified. Sialidase-specific motifs (GPG, YRVP and Asp-Box) were well conserved in the medaka neu4 polypeptide. Optimal pH of medaka neu4 sialidase was 4.6, but its activity was sustained even at neutral and weak alkaline pH. The neu4 considerably cleaved sialic acid from 4-methylumbelliferyl-N-acetyl-α-D-neuraminic acid and sialyllactose, but not from ganglioside and fetuin, which are good substrates for human NEU4. neu4 activity was mostly detected in mitochondria/lysosome fraction after biochemical fractionation, and indirect immunofluorescence assays revealed neu4 localization in lysosome in neu4 overexpressed cells. Next, developmental change in medaka neu4 and other sialidase mRNA levels were estimated by real-time PCR. Each sialidases showed different expression patterns in embryonic development: neu4 was up-regulated at late developmental stage in embryo, and neu3a mRNA level was quite high in 0.5 dpf. On the other hand, neu3b expression was drastically increased after hatching, suggesting that each sialidase may play a different role in embryonic development.


Asunto(s)
Encéfalo/metabolismo , Regulación del Desarrollo de la Expresión Génica/fisiología , Regulación Enzimológica de la Expresión Génica/fisiología , Lisosomas/enzimología , Neuraminidasa/genética , Oryzias/genética , ARN Mensajero/genética , Secuencias de Aminoácidos/genética , Animales , Fraccionamiento Químico , Clonación Molecular , Biología Computacional , Cartilla de ADN/genética , Técnica del Anticuerpo Fluorescente Indirecta/veterinaria , Regulación del Desarrollo de la Expresión Génica/genética , Regulación Enzimológica de la Expresión Génica/genética , Células HEK293 , Humanos , Concentración de Iones de Hidrógeno , Neuraminidasa/metabolismo , Oryzias/metabolismo , ARN Mensajero/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Especificidad por Sustrato
12.
Biochimie ; 95(2): 280-9, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23032629

RESUMEN

Mammalian Neu3 sialidases are involved in various biological processes, such as cell death and differentiation, through desialylation of gangliosides. The enzymatic profile of Neu3 seems to be highly conserved from birds to mammals. In fish, the functional properties of Neu3 sialidase are not clearly understood, with the partial exception of the zebrafish form. To cast further light on the molecular evolution of Neu3 sialidase, we identified the encoding genes in the medaka Oryzias latipes and investigated the properties of the enzyme. PCR amplification using medaka brain cDNA allowed identification of two novel medaka Neu3 genes, neu3a and neu3b. The YRIP, VGPG motif and Asp-Box, characteristic of consensus motifs of sialidases, were well conserved in the both medaka Neu3 sialidases. When each gene was transfected into HEK293 to allow cell lysates for the use of enzymatic characterization, two Neu3 sialidases showed strict substrate specificity toward gangliosides, similar to mammalian Neu3. The optimal pH values were at pH 4.2 and pH 4.0, respectively, and neu3b in particular showed a broad optimum. Immunofluorescence assays indicated neu3a localization at plasma membranes, while neu3b was found in cytosol. The tissue distribution of two genes was then investigated by estimation of mRNA expression and sialidase activity, both being dominantly expressed in the brain. In neu3a gene-transfected neuroblastoma cells, the enzyme was found to positively regulate retinoic acid-induced differentiation with the elongation of axon length. On the other hand, neu3b did not affect neurite formation. These results and phylogenetic analysis suggested that the medaka neu3a is an evolutionally conserved sialidase with regard to enzymatic properties, whereas neu3b is likely to have originally evolved in medaka.


Asunto(s)
Encéfalo/enzimología , Gangliósidos/metabolismo , Neuraminidasa/metabolismo , Oryzias/metabolismo , Secuencia de Aminoácidos , Animales , Membrana Celular/enzimología , Clonación Molecular , Secuencia Conservada , Citosol/enzimología , Evolución Molecular , Células HEK293 , Humanos , Concentración de Iones de Hidrógeno , Isoenzimas/genética , Isoenzimas/metabolismo , Cinética , Datos de Secuencia Molecular , Neuraminidasa/genética , Oryzias/genética , Filogenia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Especificidad por Sustrato , Pez Cebra/genética
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