Non canonical Wnt ligands and cytokine-driven myelopoiesis

Hematopoiesis is the process of blood cell production starting from undifferentiated pluripotent stem cells and finishing with diverse highly specialized cells, such as red (erythrocytes) and white (leukocytes) cells. There are various subtypes of leukocytes and they are accountable for immune, inflammatory and infection responses. For instance, granulocytes recognize and fight invading pathogens. So do monocytes, in addition to producing molecules to initiate inflammatory responses. These cells are produced by a process called myelopoiesis, which must be tightly regulated to fulfil physiological needs throughout life. This process is chiefly dependent upon a class of molecules named cytokinesFor granulocyte and monocyte production, the cytokines IL-3 and GM-CSF are the most important. Our study indicates that a molecule called Wnt5b, which is increased in expression with ageing, can skew myeloid cell differentiation. Wnt5b was previously not linked to myelopoiesis. IL-3, in the presence of Wnt5b, induced stem-cell maintenance, whilst GM-CSF unleashed a differentiation program in the presence of Wnt5b. We also investigated whether the differentiation in the presence of GM-CSF and Wnt5b was altered with aging. We provide evidence for a role for Wnt5b in regulating myeloid progenitor senescence and this was reversed by blocking Wnt5 signaling with the antagonist Box5. Blocking Wnt5 might have therapeutic use, although its risks will have to be investigated in future studies. Collectively, our studies identify mechanisms by which Wnt5 regulates hematopoietic ageing and suggests that blocking this pathway reverses some of the ageing-associated changes in myeloid cell production

Central and Systemic Responses to Methionine-Induced Hyperhomocysteinemia in Mice

Hyperhomocysteinemia has been considered a risk factor for neuropsychiatric disorders, but the mechanisms involved in this process have not been completely elucidated. the aim of this study was to analyze the influence of hyperhomocysteinemia induction by methionine supplementation considering different levels and periods of exposure in mice. for this purpose, methionine supplementation at concentrations of 0.5 and 1% were administered in water to increase homocysteinemia in male C57BL/6 mice, and was maintained for 3 time periods (2, 4 and 6 months of treatment). the results from one-carbon metabolism parameters, brain-derived neurotrophic factor (BDNF) concentrations and behavioral evaluation were compared. the 0.5% supplementation was efficient in increasing plasma homocysteine levels after 2 and 6 months. the 1% supplementation, increased plasma homocysteine after 2, 4 and 6 months. Little influence was observed in cysteine and glutathione concentrations. Frontal cortex BDNF levels showed a lack of treatment influence in all periods; only the expected decrease due to increasing age was observed. Moreover, the only behavioral alteration observed using a novel object recognition task was that which was expected with increasing age. We found that responses to hyperhomocysteinemia varied based on how it was reached, and the length of toxicity. Moreover, hyperhomocysteinemia can affect the normal pattern of one carbon metabolism during age increase in mice. These findings allow the establishment of a reliable animal model for studies in this field.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, Dept Psychobiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psychobiol, São Paulo, BrazilFAPESP: 2010/00075-2FAPESP: 2011/15699-4Web of Scienc

Wnt-5A/B Signaling in Hematopoiesis throughout Life

Wnt signaling is well-known to play major roles in the hematopoietic system, from embryogenesis to aging and disease. In addition to the main β-catenin-dependent pathway, it is now clear that Wnt5a and the structurally related Wnt5b are essential for hematopoiesis, bone marrow colonization and the final steps of hematopoietic stem cell (HSC) maturation via β-catenin-independent signaling. Wnt5a and Wnt5b ligands prevent hematopoietic exhaustion (by maintaining quiescent, long-term HSCs), induce the proliferation of progenitors, and guide myeloid development, in addition to being involved in the development of aging-related alterations. The aim of this review is to summarize the current knowledge on these roles of Wnt5a and Wn5b signaling in the hematopoietic field

Divergent effects of Wnt5b on IL-3- and GM-CSF-induced myeloid differentiation

The multiple specialized cell types of the hematopoietic system originate from differentiation of hematopoietic stem cells and progenitors (HSPC), which can generate both lymphoid and myeloid lineages. The myeloid lineage is preferentially maintained during ageing, but the mechanisms that contribute to this process are incompletely understood. Here, we studied the roles of Wnt5a and Wnt5b, ligands that have previously been linked to hematopoietic stem cell ageing and that are abundantly expressed by both hematopoietic progenitors and bone-marrow derived niche cells. Whereas Wnt5a had no major effects on primitive cell differentiation, Wnt5b had profound and divergent effects on cytokine-induced myeloid differentiation. Remarkably, while IL-3-mediated myeloid differentiation was largely repressed by Wnt5b, GM-CSF-induced myeloid differentiation was augmented. Furthermore, in the presence of IL-3, Wnt5b enhanced HSPC self-renewal, whereas in the presence of GM-CSF, Wnt5b accelerated differentiation, leading to progenitor cell exhaustion. Our results highlight discrepancies between IL-3 and GM-CSF, and reveal novel effects of Wnt5b on the hematopoietic system

Valores de referência da atividade da enzima iduronato-2-sulfatase para o diagnóstico de mucopolissacaridose II

Mucopolissacaridoses são erros inatos do metabolismo nos quais a deficiência ou falta de uma enzima faz com que os glicosaminoglicanos não sejam degradados e se acumulem nos lisossomos. O acúmulo se dá em todos os tecidos, dessa forma, a sintomatologia é multissistêmica e de gravidade variável. Essas características, unidas à baixa frequência, fazem com que a doença seja subdiagnosticada. O estudo teve como objetivo padronizar uma técnica laboratorial para a dosagem da atividade enzimática da iduronato-2-sulfatase, enzima alterada na mucopolissacaridose de tipo II, em gota seca em papel filtro (GSPF) por método fluorimétrico, tendo como material de referência a técnica em leucócitos. Os valores obtidos dos indivíduos saudáveis variaram entre 1,830-16,860 μmol/L/h em leucócitos e entre 2,710-17,360 μmol/L/h em GSPF, contra 0,650-3,060 μmol/L/h dos afetados em GSPF, que tiveram uma atividade entre 0,020-0,000 μmol/L/h em leucócitos. O melhor valor de corte, levando em consideração sensibilidade e especificidade, foi de 3,48 μmol/L/h. Este estudo possibilitou determinar o intervalo de referência da atividade da enzima iduronato-2-sulfatase em GSPF para a população brasileira, assim como validar as técnicas em leucócitos e GSP

Avaliação da diferenciação mieloide estimulada por IL-3 e GM-CSF: modulação por Wnt

Hematopoiesis is the process in which blood cells are produced and that starts with multipotent and undifferentiated stem cells and ends with with the production of several highly specialized cells, such as red cells (erythrocytes) and white cells (leukocytes). There are several types of leukocytes and they are responsible for immune, inflammatory and response to infections. These cells are produced in myelopoiesis, a process that needs to be finely regulated in order to fulfill its physiological functions throughout life. This process depends heavily on of a class of molecules called cytokines. Among these, IL-3 and GM-CSF are the most important for the production of granulocytes and monocytes. The results indicate that Wnt5b, which has its expression increased with aging, can unbalance the differentiation of myeloid cells. Wnt5b had not been associated with myelopoiesis previously. In presence of Wn5b, IL-3 stimulated maintenance of hematopoietic stem cells, while GM-CSF launched the differentiation program in the presence of Wnt5b. Furthermore, it was investigated whether the differentiation, observed in the presence of GM-CSF and Wnt5b, was altered with aging. The results provided evidence that Wnt5b regulates the senescence of parents myeloids and that this can be reversed with the use of Wnt5, Box5. The blockade of Wnt5 may come to have therapeutic use, however its risks should be investigated in future studies. In short, our studies identified mechanisms by which Wnt5 regulates aging hematopoietic and suggests that blocking this pathway reverses some of the changes in myeloid production associated with aging.Hematopoiese é o processo em que são produzidas células sanguíneas e que se inicia com células tronco multipotentes e indiferenciadas e é finalizado com a produção de diversas células altamente especializadas, tais quais células vermelhas (eritrócitos) e brancas (leucócitos). Há diversos tipos de leucócitos e eles são responsáveis por respostas imunes, inflamatórias e de resposta a infecções. Essas células são produzidas na mielopoiese, um processo que precisa ser finamente regulado para que possa cumprir suas funções fisiológicas no decorrer na vida. Este processo fortemente depende de uma classe de moléculas chamada citocinas. Entre estas, IL-3 e GM-CSF são as mais importantes para a produção de granulócitos e monócitos. Os resultados indicam que Wnt5b, que tem sua expressão aumentada com o envelhecimento, pode desequilibrar a diferenciação de células mieloides. Wnt5b não havia sido associada à mielopoiese anteriormente. Na presença de Wn5b, IL-3 estimulou manutenção de células tronco hematopoiéticas, enquanto GM-CSF desencadeou o programa de diferenciação em presença de Wnt5b. Ademais investigou-se se a diferenciação, observada na presença de GM-CSF e Wnt5b, estava alterada com o envelhecimento. Os resultados forneceram evidências de que Wnt5b regula a senescência de progenitores mieloides e de que isso pode ser revertido com o uso do bloqueador de Wnt5, Box5. O bloqueio de Wnt5 pode vir a ter uso terapêutico, contudo seus riscos devem ser investigados em estudos futuros. Em suma, nossos estudos identificaram mecanismos pelos quais Wnt5 regula o envelhecimento hematopoiético e sugere que o bloqueio dessa via reverte algumas das alterações na produção mieloide associadas com o envelhecimento.Dados abertos - Sucupira - Teses e dissertações (2020

Lee index results over time (N = 10–22).

<p>CT = Control. M05 = Methionine 0.5%. M1 = Methionine 1%. Data presented comprise all animals at the specific time points. Data are presented as the mean ± SEM.</p

Cysteine and glutathione (μM) concentrations in plasma after 2, 4 and 6 months of water or 0.5 and 1% methionine solution treatments.

<p>CT = Control. M05 = Methionine 0.5%. M1 = Methionine 1%. (N = 9–11). *<i>p</i> = 0.03 (Tukey's <i>post hoc</i> test) when compared with CT group in same period. Data are presented as the mean ± SEM.</p

Plasma homocysteine concentration after 2, 4 and 6 months of treatment with water, methionine 0.5 and 1% solutions.

<p>(N = 9–11). CT = Control. M05 = Methionine 0.5%. M1 = Methionine 1%. * = <i>p</i>≤0.05 (Tukey's <i>post hoc</i> test) when compared with the CT group at the same period. # = <i>p</i>≤0.05 (Tukey's <i>post hoc</i> test) when compared with the M05 group at the same period. Data are presented as the mean ± SEM.</p