Identification of genes regulated by mir-363*, a regulator of bone marrow endothelial cell properties

As células estaminais hematopoiéticas residem na medula óssea e possuem capacidade para se auto-renovar e dar origem a todos os tipos de células sanguíneas. O endotélio da medula óssea é constituído por células endoteliais de medula óssea (BMEC) e compreende dois nichos com funções distintas: o nicho osteoblástico e o nicho vascular. O nicho osteoblásctico proporciona condições para a quiescência de células estaminais hematopoiéticas, enquanto no nicho vascular ocorre proliferação e diferenciação das mesmas. Quando ocorre um desequilíbrio na expressão de genes que codificam para proteínas envolvidas na mobilização de células do nicho osteoblástico para o nicho vascular – factores angiócrinos – ocorre uma desestabilização do microambiente medular, que se pode traduzir num processo tumoral. Os microRNAs (miRNAs) são uma classe de RNAs não codificantes, de cadeia simples, que regula a expressão génica. Os miRNAs são sequências endógenas de RNA que possuem entre 19 e 25 nucleótidos de tamanho. Os miRNAs são reguladores da expressão genica, induzindo o silenciamento a nível da pós-transcrição, através da sua ligação com uma sequência específica para a qual possuem afinidade, na região 3’ não traduzida (3’ UTR) dos seus mRNA alvo, conduzindo à inibição da tradução ou à sua degradação. Os miRNAs estão envolvidos na regulação de genes de diversas vias afectando processos fundamentais como hematopoiese, apoptose, proliferação celular e tumorigénese. Os níveis de expressão dos miRNAs estão alterados no cancro, podendo actuar directamente como supressores de tumor ou como oncogenes, sendo neste caso denominados de oncomirs. Os perfis dos níveis de expressão de vários miRNAs foram estudados, tendo-se verificado que se alteram durante o processo de carcinogénese, podendo actuar directamente como supressores de tumor ou como oncogenes, sendo neste caso denominados de oncomirs. Apesar do miR-363* estar envolvido na regulação da expressão de genes que regulam propriedades das células endoteliais e medula óssea, os genes sobre os quais exerce a sua função ainda não foram identificados.O objectivo do presente estudo é a identificação dos genes directamente regulados pelo miR-363* (genes alvo) e a sua relevância para a disfunção medular e a sua caracterização nos síndromes mielodisplásicos. A estratégia usada baseou-se na redução ou aumento forçados dos níveis de miR-363* em células endoteliais e subsequente análise da expressão génica através de microarrays de cDNA do genoma humano. A redução do miR-363* vai implicar o aumento da expressão dos seus genes alvo, assim como o aumento dos níveis do miR-363* vai induzir a degradação e consequente redução dos seus genes alvos. A intersecção dos dados gerados através do estudo da expressão com bases de dados que possuem algoritmos para previsão de genes alvo directos dos miRNAs (miRBase e MicroCosm Targets) permitiu restringir os genes a analisar a sete genes, nomeadamente BST1, ESAM, FCER1G, IKBKG, SELE, THBS3 e TIMP1. A interacção directa destes candidatos a alvos directos do miR-363* foi posteriormente validada. Para tal, as 3’UTR dos genes foram clonadas num vector que contém o gene da luciferase. Uma vez as clonagens realizadas, efectuaram-se ensaios funcionais em células endoteliais, nomeadamente HUVEC, nas quais se co-transfectaram os vectores gerados, anti-miRs ou pre-miRs (para diminuir ou aumentar o nível de miRNA) e o plasmídeo controlo da Renilla para normalização dos ensaios de luciferase. A variação da luminescência obtida em presença do aumento ou redução do miR-363* deu uma forte indicação da regulação directa do miR-363* nesses alvos. No entanto, a confirmação desta interacção directa foi efectuada através de ensaios de mutagénese, nos quais de induziram mutações na 3’UTR nos locais de ligação do miRNA, seguidos dos ensaios funcionais como acima descritos. Esta estratégia sugere que o TIMP1, inibidor da metaloprotease-9 (MMP-9), é regulado directamente pelo miR-363*. Adicionalmente, os níveis de expressão dos alvos directos do miR-363* foram estudados em 17 amostras de aspirados de medula óssea de doentes com síndromes mielodisplásicos. Os síndromes mielodisplásicos são caracterizados como um grupo heterogéneo de condições, que apresentam citopenias (produção deficiente de eritrócitos, leucócitos e/ou megacariócitos) e medula óssea displástica e hipercelular. A escalonagem dos doentes foi feita de acordo com o sistema de prognóstico IPSS elaborado pela Organização Mundial de Saúde, e que consiste numa tabela de risco de progressão de síndromes mielodisplásicos para leucemia mielóide aguda (LMA) e que agrupa os doentes em baixo risco – que compreende os níveis baixo e intermédio 1 – e em alto risco – que compreende os níveis intermédio 2 e alto. Dos genes regulados pelo miR-363*, o destacam-se o TIMP1, estando aumentando em doentes com mau prognóstico, e o THBS3 que apresenta um aumento nos doentes com prognóstico intermédio. Em suma, os estudos realizados permitiram a identificação de genes regulados pelo miR-363* e contribuiram para o conhecimento de como o miR-363* contribui para a disfunção medular, particularmente em síndromes mielodisplásicos, pela desregulação das propriedades endoteliais.

Identification of renin progenitors in the mouse bone marrow that give rise to B-cell leukaemia

cell of origin and triggering events for leukaemia are mostly unknown. Here we show that the bone marrow contains a progenitor that expresses renin throughout development and possesses a B-lymphocyte pedigree. This cell requires RBP-J to differentiate. Deletion of RBP-J in these renin-expressing progenitors enriches the precursor B-cell gene programme and constrains lymphocyte differentiation, facilitated by H3K4me3 activating marks in genes that control the pre-B stage. Mutant cells undergo neoplastic transformation, and mice develop a highly penetrant B-cell leukaemia with multi-organ infiltration and early death. These reninexpressing cells appear uniquely vulnerable as other conditional models of RBP-J deletion do not result in leukaemia. The discovery of these unique renin progenitors in the bone marrow and the model of leukaemia described herein may enhance our understanding of normal and neoplastic haematopoiesis.

Bone marrow chimeric mice reveal a role for CX3CR1 in maintenance of the monocyte-derived cell population in the olfactory neuroepithelium

Macrophages in the olfactory neuroepithelium are thought to play major roles in tissue homeostasis and repair. However, little information is available at present about possible heterogeneity of these monocyte-derived cells, their turnover rates, and the role of chemokine receptors in this process. To start addressing these issues, this study used Cx3cr1gfp mice, in which the gene sequence for eGFP was knocked into the CX3CR1 gene locus in the mutant allele. Using neuroepithelial whole-mounts from Cx3cr1gfp/+ mice, we show that eGFP+ cells of monocytic origin are distributed in a loose network throughout this tissue and can be subdivided further into two immunophenotypically distinct subsets based on MHC-II glycoprotein expression. BM chimeric mice were created using Cx3cr1gfp/+ donors to investigate turnover of macrophages (and other monocyte-derived cells) in the olfactory neuroepithelium. Our data indicate that the monocyte-derived cell population in the olfactory neuroepithelium is actively replenished by circulating monocytes and under the experimental conditions, completely turned over within 6 months. Transplantation of Cx3cr1gfp/gfp (i.e., CX3CR1-deficient) BM partially impaired the replenishment process and resulted in an overall decline of the total monocyte-derived cell number in the olfactory epithelium. Interestingly, replenishment of the CD68lowMHC-II+ subset appeared minimally affected by CX3CR1 deficiency. Taken together, the established baseline data about heterogeneity of monocyte-derived cells, their replenishment rates, and the role of CX3CR1 provide a solid basis to further examine the importance of different monocyte subsets for neuroregeneration at this unique frontier with the external environment.

Novel characterization of monocyte-derived cell populations in the meninges and choroid plexus and their rates of replenishment in bone marrow chimeric mice

The mouse dura mater, pia mater, and choroid plexus contain resident macrophages and dendritic cells (DCs). These cells participate in immune surveillance, phagocytosis of cellular debris, uptake of antigens from the surrounding cerebrospinal fluid and immune regulation in many pathologic processes. We used Cx3cr1 knock-in, CD11c-eYFP transgenic and bone marrow chimeric mice to characterize the phenotype, density and replenishment rate of monocyte-derived cells in the meninges and choroid plexus and to assess the role of the chemokine receptor CX3CR1 on their number and tissue distribution. Iba-1 major histocompatibility complex (MHC) Class II CD169 CD68 macrophages and CD11c putative DCs were identified in meningeal and choroid plexus whole mounts. Comparison of homozygous and heterozygous Cx3cr1 mice did not reveal CX3CR1-dependancy on density, distribution or phenotype of monocyte-derived cells. In turnover studies, wild type lethally irradiated mice were reconstituted with Cx3cr1/-positive bone marrow and were analyzed at 3 days, 1, 2, 4 and 8 weeks after transplantation. There was a rapid replenishment of CX3CR1-positive cells in the dura mater (at 4 weeks) and the choroid plexus was fully reconstituted by 8 weeks. These data provide the foundation for future studies on the role of resident macrophages and DCs in conditions such as meningitis, autoimmune inflammatory disease and in therapies involving irradiation and hematopoietic or stem cell transplantation.

Graft versus host disease in a rat small bowel transplant model after T-cell depleted donor specific bone marrow infusion

Baixas doses de irradiação associadas à infusão de células da medula óssea não previnem a ocorrência da reação do enxerto versus hospedeiro após o transplante intestinal. OBJETIVO: Neste estudo foi avaliado a potencial vantagem em estender o regime imunossupressor associado a infusão de células de medula óssea do doador depletadas de células T na prevenção da reação do enxerto versus hospedeiro após o transplante intestinal. MÉTODOS: Transplante heterotópico de intestino delgado foi realizado em ratos Lewis como receptores e da como doadores, distribuídos em cinco grupos de acordo com a duração da imunossupressão, irradiação e do uso de medula óssea normal ou depletada: G1 (n=6), sem irradiação e G2 (n=9), G3 (n=4), G4 (n=5) e G5 (n=6) foram irradiados com 250 rd. Grupos1, 2, 4 e G3 e 5 foram infundidos com 100 x 10(6) células da medula normal e depletada respectivamente. Animais no G1,2,3 foram imunossuprimidos com 1mg/kg/FK506/ IM por cinco dias e G4 e cinco por 15 dias. Anticorpos monoclonais contra células CD3 e colunas magnéticas foram utilizadas para a depleção da medula óssea. Os animais foram examinados para a presença de rejeição, reação do enxerto versus hospedeiro, chimerismo e biópsias intestinais e da pele. RESULTADOS: Rejeição mínima foi observada em todos os grupos; entretanto, a reação do enxerto versus hospedeiro somente nos animais irradiados. Extensão da imunossupressão alterou a gravidade da reação nos animais dos G4 e 5. Rejeição foi a causa mortis no G1 e a reação do enxerto versus hospedeiro nos Grupos 2,3,4 e 5, não controlada com a infusão de medula óssea depletada. O chimerismo total e de células T do doador foi estatisticamente maior nos grupos irradiados em comparação ao G1. CONCLUSÃO: A extensão do regime de imunossupressão associado a baixas doses de irradiação diminui a gravidade da reação do enxerto versus hospedeiro, não abolida pelo uso de medula óssea depletada.

Microscopic Evidences That Bone Marrow Mononuclear Cell Treatment Improves Sciatic Nerve Regeneration After Neurorrhaphy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Clinical outcome in chronic myeloid leukemia after allogeneic hematopoietic stem cell transplantation: The experience of the Bone Marrow Transplantation Unit of FUNFARME/BRAZIL using FISH

Investigation of the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in chronic myeloid leukemia patients is essential to predict prognosis and survival. In 20 patients treated at the Bone Marrow Transplantation Unit of São José do Rio Preto (São Paulo, Brazil), we used fluorescence in situ hybridization (FISH) to investigate the frequency of cells with BCR/ABL rearrangement at diagnosis and at distinct intervals after allo-HSCT until complete cytogenetic remission (CCR). We investigated the disease-free survival, overall survival in 3 years and transplant-related mortality rates, too. Bone marrow samples were collected at 1, 2, 3, 4, 6, 12, and 24 months after transplantation and additional intervals as necessary. Success rate of the FISH analyses was 100%. CCR was achieved in 75% of the patients, within on average of 3.9 months; 45% patients showed CCR within 60 days after HSCT. After 3 years of the allo-HSCT, overall survival rate was 60%, disease-free survival was 50% and the transplant-related mortality rate was 40%. The study demonstrated that the BCR-ABL FISH assay is useful for follow-up of chronic myeloid leukemia patients after HSCT and that the clinical outcome parameters in our patient cohort were similar to those described for other bone marrow transplantation units. ©FUNPEC-RP.

Influence of Delivery Method on Neuroprotection by Bone Marrow Mononuclear Cell Therapy following Ventral Root Reimplantation with Fibrin Sealant

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Long-Term Spinal Ventral Root Reimplantation, but not Bone Marrow Mononuclear Cell Treatment, Positively Influences Ultrastructural Synapse Recovery and Motor Axonal Regrowth

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cardiomyopathy and cell therapy: ejection fraction improvement and cardiac muscle mass increasing, after a year of bone marrow stem cells transplantation, by magnetic resonance image

The idiopathic dilated cardiomyopathy (IDC) is one of the major public health problems in the western world. Patients with IDC in functional class IV (New York Health Association - NYHA), even after therapeutic optimization, have high mortality. Stem cell therapy has emerged as a potential therapeutic option for cell death-related heart diseases and several positive effects were assigned to cell therapy in cardiomyopathy. The aim of this study was identify short-term result of cell transplantation in idiopathic dilated cardiomyopathy patients (IDC) who were treated by transplantation of autologous bone marrow mononuclear cells (BMMC). Intracoronary injections of autologous BMMC were performed in eight patients with severe ventricle dysfunction (mean of left ventricle ejection fraction – LEVF=20.03%), cardiac mass muscle around 156.2 g and NYHA between III and IV grades, other 8 IDC patients received placebo. The IDCs were followed - up for one and two years, by magnetic resonance imaging (MRI). The results after one year showed significant improvement in LVEF (mean=181.4) and muscle mass increasing (mean=181.4 g), after two years the LVEF continued improving, reaching a mean of 32.69% and the cardiac muscle mass kept stable (mean=179.4 g). Excepted for one patient, all the other had improvement in the NYHA functional class. The placebo group did not show any improvement. We believe that BMMC implant may be a beneficial therapeutic option for IDC patients.

Protective effects of bone marrow mononuclear cell therapy on lung and heart in an elastase-induced emphysema model

We hypothesized that bone marrow-derived mononuclear cell (BMDMC) therapy protects the lung and consequently the heart in experimental elastase-induced emphysema. Twenty-four female C57BL/6 mice were intratracheally instilled with saline (C group) or porcine pancreatic elastase (E group) once a week during 4 weeks. C and E groups were randomized into subgroups receiving saline (SAL) or male BMDMCs (2 x 10(6), CELL) intravenously 3 h after the first saline or elastase instillation. Compared to E-SAL group, E-CELL mice showed, at 5 weeks: lower mean linear intercept, neutrophil infiltration, elastolysis, collagen fiber deposition in alveolar septa and pulmonary vessel wall, lung cell apoptosis, right ventricle wall thickness and area, higher endothelial growth factor and insulin-like growth factor mRNA expressions in lung tissue, and reduced platelet-derived growth factor, transforming growth factor-beta, and caspase-3 expressions. In conclusion, BMDMC therapy was effective at modulating the inflammatory and remodeling processes in the present model of elastase-induced emphysema. (c) 2012 Elsevier B.V. All rights reserved.

Detection of the Epstein-Barr virus in blood and bone marrow mononuclear cells of patients with aggressive B-cell non-Hodgkin's lymphoma is not associated with prognosis

The Epstein-Barr virus (EBV) is associated with a large spectrum of lymphoproliferative diseases. Traditional methods of EBV detection include the immunohistochemical identification of viral proteins and DNA probes to the viral genome in tumoral tissue. The present study explored the detection of the EBV genome, using the BALF5 gene, in the bone marrow or blood mononuclear cells of patients with diffuse large B-cell lymphomas (DLBCL) and related its presence to the clinical variables and risk factors. The results show that EBV detection in 21.5% of patients is not associated with age, gender, staging, B symptoms, international prognostic index scores or any analytical parameters, including lactate dehydrogenase (LDH) or beta-2 microglobulin (B2M). The majority of patients were treated with R-CHOP-like (rituximab. cyclophosphamide, doxorubicin, vincristine and prednisolone or an equivalent combination) and some with CHOP-like chemotherapy. Response rates [complete response (CR) + partial response (PR)] were not significantly different between EBV-negative and -positive cases, with 93.2 and 88.9%, respectively. The survival rate was also similar in the two groups, with 5-year overall survival (OS) rates of 64.3 and 76.7%, respectively. However, when analyzing the treatment groups separately there was a trend in EBV-positive patients for a worse prognosis in patients treated with CHOP-like regimens that was not identified in patients treated with R-CHOP-like regimens. We conclude that EBV detection in the bone marrow and blood mononuclear cells of DLBC patients has the same frequency of EBV detection on tumoral lymphoma tissue but is not associated with the risk factors, response rate and survival in patients treated mainly with immunochemotherapy plus rituximab. These results also suggest that the addition of rituximab to chemotherapy improves the prognosis associated with EBV detection in DLBCL.