Search

The human epidermal melanocyte (hEM) are melanin-producing cells that provide skin pigmentation and protection against ultraviolet radiation. Although purinergic signaling is involved in skin biology and pathology, the presence of NTPDase members, as well as the rate of nucleotides degradation by melanocytes were not described yet. Therefore, in this study we analyzed the expression of ectonucleotidases in hEM derived from discarded foreskin of male patients. The expression of purinergic enzymes was confirmed by mRNA and flow cytometry. Among the ectonucleotidases, ectonucleoside triphosphate diphosphohydrolasel (NTPDasel) and ecto-5'-nucleotidase were the ectoenzymes with higher expressions. The hydrolysis rate for ATP, ADP, and AMP was low in comparison to other primary cells already investigated. The amount of ATP in the culture medium was increased after a scratch wound and decreased to basal levels in 48 h, while the NTPDasel and P2X7 expressions increased. Therefore, it is possible to suggest that after cell injury, the ATP released by hEM into the extracellular space will be hydrolyzed by ectonucleotidases as the NTPDasel that will control the levels of nucleotides in the skin micro-environment. Key words: primary human epidermal melanocytes, NTPDases, CD73, NPPs, extracellular nucleotides, Introduction Melanocytes are melanin-producing neural crest-derived cells, present in the basal layer of human epidermis, in hair, eye, inner ear, brain, lungs, heart, and adipose tissue (Quevedo and Fleischmann 1980; [...]

Genetic analyses were undertaken on archived otoliths from juveniles representing historically strong year classes of northwest Atlantic redfish (Sebastes spp.) and on tissue samples from adults of known species and population of origin. The results indicated that the species composition of a year class is key information for understanding recruitment dynamics, with redfish species having distinct population-associated patterns of spatial dispersion. In the Gulf of St. Lawrence--Laurentian Channel area (GSL-LCH), the last strong year class (which supported the fishery for more than 30 years) belonged to Sebastes mentella and originated from the area. In contrast, four year classes that appeared abundant at young ages in research surveys in GSL-LCH but contributed only marginally to the adult population and the fishery of the region belonged to Sebastes fasciatus and carried the genetic signature of the adult population from the slope of the Newfoundland Grand Banks. Ocean currents and spatiotemporal trends in abundance-at-length suggest that the latter population uses the Gulf of St. Lawrence as a nursery area, with larvae and early juveniles drifting toward the Gulf of St. Lawrence and older juveniles migrating back to the slope of the Grand Banks after about 5-6 years. It is suggested that juvenile migration behaviour is a postsettlement process that plays an important role in redfish recruitment dynamics and carries both demographic and evolutionary implications. Des analyses genetiques ont ete realisees a partir d'otolithes archives appartenant aux juveniles de fortes classes d'age historiques de sebaste (Sebastes spp.) du nord-ouest Atlantique et d'echantillons de tissu preleves sur des adultes d'espece et de population d'origine connues. Les resultats ont montre que la composition specifique d'une classe d'age constitue une information clef pour la comprehension de la dynamique de recrutement, en revelant que les especes de sebaste ont des patrons de dispersion spatiale distincts et propres aux populations. Dans la region du Golfe du Saint-Laurent et du chenal Laurentien (GSL-LCH), la derniere forte classe d'age (qui a supporte la peche pendant plus de 30 ans) appartenait a Sebastes mentella et etait originaire de la region. Par contre, quatre classes d'age qui semblaient abondantes a un jeune age dans les releves de recherche du GSL-LCH, mais qui ont contribue seulement marginalement a la population adulte et a la peche de la region, appartenaient a Sebastes fasciatus et portaient la signature genetique de la population adulte distribuee le long de la pente des Grands Bancs de Terre-Neuve. Les courants oceaniques et les tendances spatiotemporelles d'abondance en fonction de l'age suggerent que cette derniere population utilise le Golfe du Saint-Laurent comme zone de nurserie; les larves et jeunes juveniles deriveraient vers le Golfe du Saint-Laurent puis, 5 a 6 ans plus tard, les juveniles plus ages retourneraient vers la pente des Grands Bancs. Il est suggere que le comportement migratoire des juveniles joue un role significatif dans la dynamique de recrutement du sebaste et possede des implications aux niveaux demographique et evolutif., Introduction Episodic recruitment is commonly observed in long-lived marine teleost species, such as Sebastes spp. (Longhurst 2002; Love et al. 2002; Planque et al. 2012; Ralston et al. 2013). The [...]

The aim of this study was to evaluate the effect of a dietary highly unsaturated fatty acid (HUFA) deficiency on winter flounder Pseudopleuronectes americanus metamorphosis by examining the growth and the expression of genes involved in some key metabolic processes: lipid digestion, oxidative stress, and growth. Three groups of fish were fed rotifers enriched with different blends of microalgae providing different HUFA profiles: (1) a diet comprising a mixture of three microalgae, Nannochloropsis oculata, Isochrysis galbana, and Pavlova lutheri (Cocktail diet), which contained a balanced combination of ecosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA); (2) the N. oculata diet (Nanno diet), with a low level of DHA; and (3) the I. galbana diet (Tiso diet), characterized by low levels of EPA and AA. The results indicate that the need for DHA increased from settlement and for EPA and AA from 15 days after settlement. The lower HUFA content in the Tiso and Nanno diets did not affect larval development or lipid reserve accumulation. The superoxide dismutase gene expression suggests a reduced oxidative stress in the Cocktail group, and overall results indicate that gh gene expression could be a valuable indicator of development at the molecular level in response to dietary HUFA quality during metamorphosis in winter flounder., Introduction In many marine fish species, metamorphosis is a critical step during which animals undergo profound physiological and morphological modifications that are controlled by a coordinated change in gene expression [...]

Twenty-two Mya arenaria samples spanning seven marine ecoregions mostly situated in the Cold Temperate Northwest Atlantic (CTNA) biogeographic province were collected between 2001 and 2010 and genotyped at seven highly polymorphic microsatellite loci to test for population differentiation. Results showed strong regional differentiation with six genetic clusters: (1) Northern Gulf of St. Lawrence (GSL), (2) Magdalen Archipelago, (3) Southern GSL, (4) Lower Atlantic Canada, (5) US Coasts and (6) Northern Europe. Population structure was supported no matter the statistical approach and generally does not reflect the geographical limits of marine ecoregions. A latitudinal cline in allelic richness provides evidence for a northward post-glacial expansion range for this species. While geographical distance explains the genetic variation detected in southern CTNA, increased heterogeneity observed in northern CTNA can be explained by isolation by distance, marine landscaping and presumable selective processes acting at the Mar5 locus. Exclusion of Mar5 from analyses resulted in the detection of three genetic clusters instead of six., Introduction Several marine invertebrate species that remain sedentary during adult stages reproduce through a pelagic larval dispersal phase (Thorson 1950; Mileikovsky 1971). The genetic structure of such species provides important [...]

Extracellular nucleotides and adenosine regulate endocrine pancreatic functions such as insulin secretion by Langerhans islet B-cells via the activation of specific P2 and P1 receptors. Membrane-bound ectonucleotidases regulate the local concentration of these ligands and consequently control the activation of their receptors. The objective of this study was to identify and localize the major ectonucleotidases, namely NTPDases and ecto-5'-nucleotidase, present in the endocrine pancreas. In addition, the potential implication of ecto-ATPase activity on insulin secretion was investigated in the rat [beta]-cell line INS-1 (832/13). The localization of ectonucleotidase activity and protein was carried out in situ by enzyme histochemistry and immunolocalization in mouse, rat, and human pancreas sections. NTPDasel was localized in all blood vessels and acini, and NTPDase2 was localized in capillaries of Langerhans islets and in peripheral conjunctive tissue, whereas NTPDase3 was detected in all Langerhans islet cell types. Interestingly, among the mammalian species tested, ecto-5'-nucleotidase was present only in rat Langerhans islet cells, where it was coexpressed with NTPDase3. Notably, the inhibition of NTPDase3 activity by BG0136 and NF279 facilitated insulin release from INS-1 (832/13) cells under conditions of low glycemia, probably by affecting P2 receptor activation. NTPDase3 activity also regulated the inhibitory effect of exogenous ATP in the presence of a high glucose concentration most likely by controlling adenosine production. In conclusion, all pancreatic endocrine ceils express NTPDase3 that was shown to modulate insulin secretion in rat INS-1 (832/13) [beta]-cells. Ecto-5'-nucleotidase is expressed in rat Langerhans islet cells but absent in human and mouse endocrine cells. nucleoside triphosphate diphosphohydrolase; ecto-5'-nucleotidase/ CD73; P2 receptors; purinergic signaling; INS-1 (832/13) doi: 10.1152/ajpendo.00126.2010.

Airway defenses are regulated by a complex purinergic signaling network located on the epithelial surfaces, where ATP stimulates the clearance of mucin and pathogens. The present study shows that the obstructive disease cystic fibrosis (CF) affects the activity, expression, and tissue distribution of two ectonucleotidases found critical for the regulation of ATP on airway surfaces: NTPDase1 and NTPDase3. Functional polarities and mRNA expression levels were determined on primary cultures of human bronchial epithelial (HBE) cells from healthy donors and CF patients. The in vitro model of the disease was completed by exposing CF HBE cultures for 4 days to supernatant of the mucopurulent material (SMM) collected from the airways of CF patients. We report that NTPDase1 and NTPDase3 are coexpressed on HBE cultures, where they regulate physiological and excess nucleotide concentrations, respectively. In aseptic conditions, CF epithelia exhibit >50% lower NTPDase1 activity, protein, and mRNA levels than normal epithelia, whereas these parameters are threefold higher for NTPDase3. Exposure to SMM induced opposite polarity shifts of the two NTPDases on both normal and CF epithelia, apical NTPDase1 being mobilized to basolateral surfaces and bilateral NTPDase3 to the apical surface. Their immunolocalization in human tissue revealed that NTPDase1 is expressed in epithelial, inflammatory, and endothelial cells, whereas NTPDase3 is restricted to epithelial cells. Furthermore, the SMM-exposed CF HBE cultures reproduced the impact of the disease on their in vivo distribution. This study provides evidence that an extensive remodeling of the enzymatic network regulating clearance occurs in the airways of CF patients. ectonucleotidase; ATP; mucociliary clearance; [P2Y.sub.2] receptors doi: 10.1152/ajplung.00019.2010.