Changes in cytoarchitecture and mobility in B16F1 melanoma cells induced by 5-Br-2'-dU coincide with Rock2, miRNAs 138-5p and 455-3p reciprocal expressions

ROCK2 is a protein involved in the restructuring of the cytoskeleton in cell adhesion and contractibility processes. miR-138-5p and miR-455-3p regulate Rock2 expression, cell proliferation, migration, and invasion in different experimental cell models. However, their participation in the cytoarchitecture and mobility of B16F1 melanoma cells exposed to 5-Br-2'-dU is partially known. This work aimed to analyze ROCK2 and miRs 138-5p and 455-3p expression associated with morphological and mobility changes of B16F1 mouse melanoma cells exposed to the thymidine analog 5-Bromo-2'-deoxyuridine (5-Br-2'-dU). We observed an increase (2.2X n = 3, p < 0.05) in the cell area, coinciding with an increase in cell diameter (1.27X n = 3, p < 0.05), as well as greater cell granularity, capacity for circularization, adhesion, which was associated with more significant polymerization of F-actin, collapsed in the intermediate filaments of vimentin (VIM), and coinciding with a decrease in migration (87%). Changes coincided with a decrease in Rock2 mRNA expression (2.88X n = 3, p < 0.05), increased vimentin and a reciprocal decrease in miR-138-5p (1.8X), and an increase in miR-455-3p (2.39X). The Rock2 kinase inhibitor Y27632 partially rescued these changes. These results suggest ROCK2 and VIM regulate the morphological and mobility changes of B16 melanoma cells after exposure to 5-Br-2'-dU, and its expression may be reciprocally regulated, at least in part, by miR-138-5p and miR-455-3p.

Reciprocal Changes in miRNA Expression with Pigmentation and Decreased Proliferation Induced in Mouse B16F1 Melanoma Cells by L-Tyrosine and 5-Bromo-2'-Deoxyuridine

Background: Many microRNAs have been identified as critical mediators in the progression of melanoma through its regulation of genes involved in different cellular processes such as melanogenesis, cell cycle control, and senescence. However, microRNAs’ concurrent participation in syngeneic mouse B16F1 melanoma cells simultaneously induced decreased proliferation and differential pigmentation by exposure to 5-Brd-2′-dU (5’Bromo-2-deoxyuridine) and L-Tyr (L-Tyrosine) respectively, is poorly understood. Aim: To evaluate changes in the expression of microRNAs and identify which miRNAs in-network may contribute to the functional bases of phenotypes of differential pigmentation and reduction of proliferation in B16F1 melanoma cells exposed to 5-Brd-2′-dU and L-Tyr. Methods: Small RNAseq evaluation of the expression profiles of miRNAs in B16F1 melanoma cells exposed to 5-Brd-2′-dU (2.5 μg/mL) and L-Tyr (5 mM), as well as the expression by qRT-PCR of some molecular targets related to melanogenesis, cell cycle, and senescence. By bioinformatic analysis, we constructed network models of regulation and co-expression of microRNAs. Results: We confirmed that stimulation or repression of melanogenesis with L-Tyr or 5-Brd-2′-dU, respectively, generated changes in melanin concentration, reduction in proliferation, and changes in expression of microRNAs 470-3p, 470-5p, 30d-5p, 129-5p, 148b-3p, 27b-3p, and 211-5p, which presented patterns of coordinated and reciprocal co-expression, related to changes in melanogenesis through their putative targets Mitf, Tyr and Tyrp1, and control of cell cycle and senescence: Cyclin D1, Cdk2, Cdk4, p21, and p27. Conclusions: These findings provide insights into the molecular biology of melanoma of the way miRNAs are coordinated and reciprocal expression that may operate in a network as molecular bases for understanding changes in pigmentation and decreased proliferation induced in B16F1 melanoma cells exposed to L-Tyr and 5-Brd-2′-dU.

Estradiol and the control of feeding behavior

This review lays out the evidence for the role of E2 in homeostatic and hedonic feeding across several species. While significant effort has been expended on homeostatic feeding research, more studies for hedonic feeding need to be conducted (i.e. are there increases in meal size and enhanced motivation to natural food rewards). By identifying the underlying neural circuitry involved, one can better delineate the mechanisms by which E2 influences feeding behavior. By utilizing more selective neural targeting techniques, such as optogenetics, significant progress can be made toward this goal. Together, behavioral and physiological techniques will help us to better understand neural deficits that can increase the risk for obesity in the absence of E2 (menopause) and aid in developing therapeutic strategies.

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Introducción. El virus del Zika (ZIKV) es un flavivirus con envoltura, transmitido a los seres humanos principalmente por el vector Aedes aegypti. La infección por ZIKV se ha asociado con un gran neurotropismo y con efectos neuropáticos, como el síndrome de Guillain-Barré en el adulto y la microcefalia fetal y posnatal, así como con un síndrome de infección congénita similar al producido por el virus de la rubéola (RV).Objetivo. Comparar las estructuras moleculares de la proteína de envoltura E del virus del Zika (E-ZIKV) y de la E1 del virus de la rubéola (E1-RV), y plantear posibles implicaciones en el neurotropismo y en las alteraciones del sistema nervioso asociadas con el ZIKV.Materiales y métodos. La secuencia de aminoácidos de la proteína E-ZIKV (PDB: 5iZ7) se alineó con la de la glucopreteína E1 del virus de la rubéola (PDB: 4ADG). Los elementos de la estructura secundaria se determinaron usando los programas Vector NTI Advance®, DSSP y POSA, así como herramientas de gestión de datos (AlignX®). Uno de los criterios principales de comparación y alineación fue la asignación de residuos estructuralmente equivalentes, con más de 70 % de identidad.Resultados. La organización estructural de la proteína E-ZIKV (PDB: 5iZ7) fue similar a la de E1-RV (PDB: 4ADG) (70 a 80 % de identidad), y se observó una correspondencia con la estructura definida para las glucoproteínas de fusión de membrana de clase II de los virus con envoltura. E-ZIKV y E1-RV exhibieron elementos estructurales de fusión muy conservados en la región distal del dominio II, asociados con la unión a los receptores celulares de entrada del virus de la rubéola (glucoproteína de mielina del oligodendrocito, Myelin Oligodendrocyte Glycoprotein, MOG), y con los receptores celulares Axl del ZIKV y de otros flavivirus.Conclusión. La comparación de las proteínas E-ZIKV y E1-RV es un paso necesario hacia la definición de otros factores moleculares determinantes del neurotropismo y la patogenia del ZIKV, el cual puede contribuir a generar estrategias de diagnóstico, prevención y tratamiento de las complicaciones neurológicas inducidas por el ZIKV.

Ovarian steroids increase spinogenetic proteins in the macaque dorsal raphe

Dendritic spines are the basic structural units of neuronal plasticity. Intracellular signaling cascades that promote spinogenesis have centered on RhoGTPases. We found that ovarian steroids increase gene expression of RhoGTPases [Ras homolog gene family member A (RhoA), cell division control protein 42 homolog (Cdc42), and ras-related C3 botulinum toxin substrate (Rac)] in laser-captured serotonin neurons. We sought to confirm that the increases observed in gene expression translate to the protein level. In addition, a preliminary study was conducted to determine whether an increase in spines occurs via detection of the spine marker protein, postsynaptic density-95 (PSD-95). Adult ovariectomized (Ovx) monkeys were treated with estradiol (E), progesterone (P), or E+P for 1 month. Sections through the dorsal raphe nucleus were immunostained for RhoA and Cdc42 (n=3-4/group). The number and positive pixel area of RhoA-positive cells and the positive pixel area of Cdc42-positive fibers were determined. On combining E- and E+P-treated groups, there was a significant increase in the average and total cell number and positive pixel area of RhoA-positive cells. E, P, and E+P treatments, individually or combined, also increased the average and total positive pixel area of Cdc42-positive fibers. With remaining sections from two animals in each group, we conducted a preliminary examination of the regulation of PSD-95 protein expression. PSD-95, a postsynaptic scaffold protein, was examined with immunogold silver staining (n=2/group), and the total number of PSD-95-positive puncta was determined with stereology across four levels of the dorsal raphe. E, P, and E+P treatment significantly increased the total number of PSD-95-positive puncta. Together, these findings indicate that ovarian steroids act to increase gene and protein expression of two pivotal RhoGTPases involved in spinogenesis and preliminarily indicate that an increased number of spines and/or synapses result from this action. Increased spinogenesis on serotonin dendrites would facilitate excitatory glutamatergic input and in turn, increase serotonin neuronal activity throughout the brain.