Tumor necrosis factor α, and agonist and antagonists of cannabinoid receptor type 1 and type 2 alter the immunophenotype of stem cells from human exfoliated deciduous teeth

ABSTRACT Objective To verify the involvement of the endocannabinoid system in the immunomodulatory profile of stem cells from human exfoliated deciduous teeth, in the presence or absence of TNF-α, and agonist and antagonists of CB1 and CB2. Methods Stem cells from human exfoliated deciduous teeth were cultured in the presence or absence of an agonist, anandamide, and two antagonists, AM251 and SR144528, of CB1 and CB2 receptors, with or without TNF-α stimulation. For analysis of immunomodulation, surface molecules linked to immunomodulation, namely human leukocyte antigen-DR isotype (HLA-DR), and programmed death ligands 1 (PD-L1) and 2 (PD-L2) were measured using flow cytometry. Results The inhibition of endocannabinoid receptors together with the proinflammatory effect of TNF-α resulted in increased HLA-DR expression in stem cells from human exfoliated deciduous teeth, as well as, in these cells acquiring an anti-inflammatory profile by enhancing the expression of PD-L1 and PD-L2. Conclusion Stem cells from human exfoliated deciduous teeth respond to the endocannabinoid system and TNF-α by altering key immune response molecules

Myeloproliferative neoplasms and the JAK/STAT signaling pathway: an overview

ABSTRACTMyeloproliferative neoplasms are caused by a clonal proliferation of a hematopoietic progenitor. First described in 1951 as 'Myeloproliferative Diseases' and reevaluated by the World Health Organization classification system in 2011, myeloproliferative neoplasms include polycythemia vera, essential thrombocythemia and primary myelofibrosis in a subgroup called breakpoint cluster region-Abelson fusion oncogene-negative neoplasms. According to World Health Organization regarding diagnosis criteria for myeloproliferative neoplasms, the presence of the JAK2 V617F mutation is considered the most important criterion in the diagnosis of breakpoint cluster region-Abelson fusion oncogene-negative neoplasms and is thus used as a clonal marker. The V617F mutation in the Janus kinase 2(JAK2) gene produces an altered protein that constitutively activates the Janus kinase/signal transducers and activators of transcription pathway and other pathways downstream as a result of signal transducers and activators of transcription which are subsequently phosphorylated. This affects the expression of genes involved in the regulation of apoptosis and regulatory proteins and modifies the proliferation rate of hematopoietic stem cells

Experimental practical activities for the Physics teaching: an investigation using the Central Nucleus Theory

Esta tese apresenta um estudo sobre as Representações Sociais de professores e estudantes do objeto social denominado Atividades Práticas Experimentais para o Ensino de Física. Reconhecendo que o tema já foi amplamente debatido pela literatura, adotamos uma tônica distinta, apoiando nossas pesquisas e análises no referencial teórico-metodológico da Teoria do Núcleo Central de Jean-Claude Abric, a qual se sustenta na Teoria das Representações Sociais de Moscovici. Além das técnicas consagradas, como análise prototípica e de similitude, que manifestam, respectivamente, a saliência e a conexidade dos possíveis constituintes da representação, inserimos indicadores, oriundos das Redes Complexas, com a intenção de corroborar no discernimento da centralidade das representações. Presumindo que a formação acadêmica pode influenciar na consolidação das representações, e que, por conseguinte, estas são elementos norteadores entre a dedicação e as estratégias escolhidas pelo professor em sua ação profissional, buscamos o mapeamento das Representações Sociais de diversos grupos. Para tal, coletamos dados com 444 respondentes, contemplando professores universitários de diversas universidades do país, professores da educação básica de diversas redes de ensino e estudantes universitários de duas instituições públicas. O questionário empregado compreendia questões relativas à caracterização dos respondentes, uma questão envolvendo a técnica de associação livre de palavras e questões dissertativas correlacionadas ao tema da pesquisa, sendo que a última foi aplicada exclusivamente aos docentes. Antes de tudo, cabe destacar que as análises dos dados mostraram plausibilidade na incorporação dos indicadores como técnica confirmatória para o estudo da centralidade das Representações Sociais. Os resultados apontaram um forte aceno positivo para a dimensão cognitivo-motivacional. Destacamos também a prevalência das atividades de cunho demonstrativo e/ou verificador, como estratégia de uso das atividades práticas, para subgrupos de professores dos diversos níveis; contudo, diagnosticamos um distanciamento entre os subgrupos de professores com e sem pós-graduação na área de ensino/educação, caracterizando, portanto, grupos sociais distintos. De forma análoga, notamos essa cisão entre estudantes de licenciatura e os demais cursos analisados. Essas rupturas derivam da incorporação, no Núcleo Central, de elementos que sinalizam a intencionalidade de adoção de estratégias investigativas e com maior interação. Evidencia-se, portanto, que as adequações nas representações, dos diversos grupos sociais, são frutos das exposições em culturas singulares, mesmo que diante de uma origem comum. Embora tenhamos a convicção de que a licenciatura seja responsável pela incorporação dos novos papéis e potencialidades das atividades práticas, ainda assim, os resultados da pesquisa apontam indícios da fragilidade na consolidação desses significados para os estudantes.This thesis shows a study on Social Representations of teachers and students of the social object denominated Experimental Practical Activities for the Physics Teaching. Considering that this subject has been widely debated in literature, we have adopted a different perspective which supports our research and analysis grounded on Jean-Claude Abric\'s theoretical-methodological framework: Central Nucleus Theory, which is based on Moscovici\'s Theory of Social Representations. Besides using well-known techniques such as the prototypical analysis and similitude analysis, which show, respectively, the salience and connectivity of possible constituents of the representation, we included indicators from Complex Networks in order to confirm the core of representations. Assuming that academic education may influence the consolidation of representations and, consequently, they may be guiding elements that mediate the dedication and choice of strategies by the teacher in your action, we seek to map the Social Representations of different groups. In order to do so, we collected data with 444 respondents, including university professors of several universities in the country, basic education teachers of different educational systems and university students of two public institutions. The questionnaire used included questions related to the respondents\' profiles, a question approaching the technique of free association of words and open questions correlated to the theme of the research. The last question was asked only of the teachers. First of all, it\'s important to point out that the data analysis indicated that the incorporation of the indicators as a confirmation technique for the study of the core of Social Representations is plausible. Results show a strong positive response linked to the cognitive-motivational dimension. We also highlight the prevalence of demonstrative and/or confirmation activities as a strategy chosen by the teachers of different educational levels when using practical activities. However, we noticed a difference in the use of these strategies between the subgroups of teachers with and without post-graduation in the area of teaching/education which characterized them as belonging to different social groups. Analogously, we noted a difference in choices made by the undergraduate students in teacher training courses and the other courses analyzed. These differences derive from the incorporation, in the Central Nucleus, of elements that signal the intentionality of adopting investigative strategies and with greater interaction. Indicating, therefore, that the adaptations in the representations, of the various social groups, are fruits of the expositions in singular cultures, even if in front of a common origin. Although we believe that being pre-service teacher education is responsible for incorporating the new roles to the use of practical activities, the results of the research point to signs of fragility in the consolidation of these meanings for the students

Low-intensity laser phototherapy enhances the proliferation of dental pulp stem cells under nutritional deficiency

Abstract Dental trauma in immature permanent teeth can damage pulp vascularization, which leads to necrosis and cessation of apexogenesis. Studies on tissue engineering using stem cells from human exfoliated deciduous teeth (SHEDs) have yielded promising results. Laser phototherapy (LPT) is able to influence the proliferation and differentiation of these cells, which could improve tissue engineering. SHEDs (eighth passage) were seeded into 96-well culture plates (103 cells/well) and were grown in culture medium supplemented with 15% defined fetal bovine serum (FBS) for 12 h. After determining the appropriate nutrition deficiency status (5% FBS), the cells were assigned into four groups: 1) G1 &#8211; 15% FBS (positive control); 2) G2 &#8211; 5% FBS (negative control); 3) G3 &#8211; 5% FBS+LPT 3 J/cm2; and 4) G4 &#8211; 5% FBS+LPT 5 J/cm2. For the LPT groups, two laser irradiations at 6 h intervals were performed using a continuous wave InGaAlP diode laser (660 nm, with a spot size of 0.028 cm2, 10 mW) in punctual and contact mode. Cell viability was assessed via an MTT reduction assay immediately after the second laser irradiation (0 h) and 24, 48, and 72 h later. We found that G3 and G4 presented a significantly higher cell growth rate when compared with G2 (p < 0.01). Moreover, G4 exhibited a similar cell growth rate as G1 throughout the entire experiment (p > 0.05). These findings indicate that LPT with 5 J/cm2 can enhance the growth of SHEDs during situations of nutritional deficiency. Therefore, LPT could be a valuable adjunct treatment in tissue engineering when using stem cells derived from the dental pulp of primary teeth

Dental pulp stem cells express proteins involved in the local invasiveness of odontogenic myxoma

Little is known about the histogenesis of the odontogenic myxoma (OM). Dental pulp stem cells could be candidate precursors of OM because both OM and the dental pulp share the same embryological origin: the dental papilla. For the purpose of comparing OM and stem cells, this study analyzed the expression of two proteins related to OM invasiveness (MMP-2 and hyaluronic acid) in human immature dental pulp stern cells (hIDPSCs). Three lineages of hIDPSCs from deciduous and permanent teeth were used in this study. Immunofluorescence revealed positive reactions for MMP-2 and hyaluronic acid (HA) in all hIDPSCs. MMP-2 appeared as dots throughout the cytoplasm, whereas HA appeared either as diffuse and irregular dots or as short fibrils throughout the cytoplasm and outside the cell bodies. The gene expression profile of each cell lineage was evaluated using RT-PCR analysis, and HA was expressed more intensively than MMP-2. HA expression was similar among the three hIDPSCs lineages, whereas MMP-2 expression was higher in DL-1 than in the other cell lines. The expression of proteins related to OM invasiveness in hIDPSCs could indicate that OM originates from dental pulp stem cells

Photobiomodulation enhancement of cell proliferation at 660 nm does not require cytochrome c oxidase

Photobiomodulation (PBM) therapy is based on the use of specific light parameters to promote tissue repair. Although demonstrated in different cell models and tissues, the mechanism by which photobiomodulation operates is not well understood. Previous studies suggested that the cell proliferation enhancement triggered by red and near-infrared PBM involves the activation of the mitochondrial respiratory chain enzyme cytochrome c oxidase (CCO). It was suggested that light in this range would displace inhibitory nitric oxide bound to CCO. To test this mechanism, we took advantage of cell lines lacking CCO, including a mouse line knockout for Cox10 (a gene required for the synthesis of heme a, the prosthetic group of CCO) and a human cell line with an mtDNA mutation in the tRNA Lysine gene, leading to mitochondrial protein synthesis impairment and the lack of three critical CCO subunits. In both models we showed the complete absence of assembled CCO. PBM (660 nm) was applied to these proliferating cells using various parameters. In most of the conditions tested, increased cell proliferation was associated with PBM in both control and CCO negative cells, demonstrating that CCO is not required for PBM enhancement of cellular proliferation. Additional experiments showed that PBM increased both ATP levels and citrate synthase activity and levels. These results showed that although metabolic changes are associated with PBM, CCO is not required for its cell proliferation enhancing effect. [Display omitted] •The mechanism of photobiomodulation is believed to involve cytochrome c oxidase (CCO).•We developed and characterized two cell models lacking CCO.•Enhanced proliferation of cells lacking CCO was still observed after PBM at 660 nm.•ATP and citrate synthase levels increased with PBM at 660 nm in cells lacking CCO.•These data show that CCO is not required for PBM at 660 nm

Expression of Extracellular Matrix Proteins in Human Dental Pulp Stem Cells Depends on the Donor Tooth Conditions

Introduction: Stem cells are characterized by the ability to renew themselves through mitotic cell division and differentiating into a diverse range of specialized cell types. An important source of adult stem cells is the dental pulp. In dentistry, regenerative strategies are of importance because of hard dental tissue damage especially as result of caries lesions, trauma, or iatrogenic procedures. The regeneration of dental tissues relies on the ability of stem cells to produce extracellular (ECM) proteins encountered in the dental pulp tissue. Thus, the aim of this study was to analyze the expression and distribution of proteins encountered in dental pulp ECM (type I collagen, fibronectin, and tenascin) in stem cells. Methods: Human immature dental pulp stem cells (hIDPSCs) from deciduous (DL-1 and DL-4 cell lines) and permanent (DL-2) teeth were used. The distribution of ECM proteins was observed using the immunofluorescence technique. The gene expression profile was evaluated using reverse transcription polymerase chain reaction (RT-PCR) analysis. Results: Positive reactions for all ECM proteins were observed independently of the hIDPSCs analyzed. Type I collagen appeared less evident in DL-2 than in other hIDPSCs. Fibronectin and tenascin were less clear in DL-4. The RT-PCR reactions showed that type I collagen was lesser expressed in the DL-2 cells, whereas fibronectin and tenascin were similarly expressed in all hIDPSCs. Conclusions: The distribution and expression of ECM proteins differ among the hIDPSCs. These differences seemed to be related to the donor tooth conditions (deciduous or permanent, retained or erupted, and degree of root reabsorption). (J Endod 2010;36:826-831)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenmvolvimento Cientifico e Tecnologico (CNPq)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (Capes