Age-related Morphofunctional Changes in Sickle Cell Mice Bone Marrow Mesenchymal Stromal Cells.

BACKGROUND AND OBJECTIVES: Bone marrow mesenchymal stromal cells (BM-MSCs) are key elements of the hematopoietic niche and participate in the regulatory mechanisms of hematopoietic stem cells (HSCs). Hematological diseases can affect MSCs and their functions. However, the dysregulations caused by sickle cell disease (SCD) are not fully elucidated. This work explored changes in BM-MSCs and their relationship with age using sickle cell mice (Townes-SS). MATERIALS AND METHODS: BM-MSCs were isolated from Townes-SS, and control groups 30- and 60-day-old Townes-AA and C57BL/6 J. RESULTS: The BM-MSCs showed no morphological differences in culture and demonstrated a murine MSC-like immunophenotypic profile (Sca-1+, CD29+, CD44+, CD90.2+, CD31-, CD45-, and CD117-). Subsequently, all BM-MSCs were able to differentiate into adipocytes and osteocytes in vitro. Finally, 30-day-old BM-MSCs of Townes-SS showed higher expression of genes related to the maintenance of HSCs (Cxcl12, Vegfa, and Angpt1) and lower expression of pro-inflammatory genes (Tnfa and Il-6). However, 60-day-old BM-MSCs of Townes-SS started to show expression of genes related to reduced HSC maintenance and increased expression of pro-inflammatory genes. CONCLUSION: These results indicates age as a modifying factor of gene expression of BM-MSCs in the context of SCD.

Immunological Balance Is Associated with Clinical Outcome after Autologous Hematopoietic Stem Cell Transplantation in Type 1 Diabetes.

Autologous hematopoietic stem cell transplantation (AHSCT) increases C-peptide levels and induces insulin independence in patients with type 1 diabetes. This study aimed to investigate how clinical outcomes may associate with the immunological status, especially concerning the balance between immunoregulation and autoreactivity. Twenty-one type 1 diabetes patients were monitored after AHSCT and assessed every 6 months for duration of insulin independence, C-peptide levels, frequencies of islet-specific autoreactive CD8+ T cells (CTL), regulatory lymphocyte subsets, thymic function, and T-cell repertoire diversity. In median follow-up of 78 (range 15-106) months, all patients became insulin-independent, resuming insulin after median of 43 (range 6-100) months. Patients were retrospectively divided into short- or prolonged-remission groups, according to duration of insulin independence. For the entire follow-up, CD3+CD4+ T-cell numbers remained lower than baseline in both groups, whereas CD3+CD8+ T-cell levels did not change, resulting in a CD4/CD8 ratio inversion. Memory CTL comprehended most of T cells detected on long-term follow-up of patients after AHSCT. B cells reconstituted to baseline levels at 2-3 months post-AHSCT in both patient groups. In the prolonged-remission-group, baseline islet-specific T-cell autoreactivity persisted after transplantation, but regulatory T cell counts increased. Patients with lower frequencies of autoreactive islet-specific T cells remained insulin-free longer and presented greater C-peptide levels than those with lower frequencies of these cells. Therefore, immune monitoring identified a subgroup of patients with superior clinical outcome of AHSCT. Our study shows that improved immunoregulation may balance autoreactivity endorsing better metabolic outcomes in patients with lower frequencies of islet-specific T cells. Development of new strategies of AHSCT is necessary to increase frequency and function of T and B regulatory cells and decrease efficiently autoreactive islet-specific T and B memory cells in type 1 diabetes patients undergoing transplantation.

Immunological correlates of favorable long-term clinical outcome in multiple sclerosis patients after autologous hematopoietic stem cell transplantation.

High dose immunosuppression followed by autologous hematopoietic stem cell transplantation (AHSCT) induces prolonged clinical remission in multiple sclerosis (MS) patients. However, how patient immune profiles are associated with clinical outcomes has not yet been completely elucidated. In this study, 37 MS patients were assessed for neurological outcomes, thymic function and long-term immune reconstitution after AHSCT. Patients were followed for a mean (SD) of 68.5 (13.9) months post-transplantation and were retrospectively clustered into progression- and non-progression groups, based on Expanded Disease Status Scale (EDSS) outcomes at last visit. After AHSCT, both patient groups presented increased regulatory T-cell subset counts, early expansion of central- and effector-memory CD8(+)T-cells and late thymic reactivation. However, the non-progression group presented early expansion of PD-1(+)CD8(+)T-cells and of PD-1-expressing CD19(+) B-cells. Here, we suggest that along with increased numbers of regulatory T-cell subsets, PD-1 inhibitory signaling is one possible immunoregulatory mechanism by which AHSCT restores immune tolerance in MS patients.

Bone marrow mesenchymal stromal cells isolated from multiple sclerosis patients have distinct gene expression profile and decreased suppressive function compared with healthy counterparts.

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system, due to an immune reaction against myelin proteins. Multipotent mesenchymal stromal cells (MSCs) present immunosuppressive effects and have been used for the treatment of autoimmune diseases. In our study, gene expression profile and in vitro immunomodulatory function tests were used to compare bone marrow-derived MSCs obtained from MS patients, at pre- and postautologous hematopoietic stem cell transplantation (AHSCT) with those from healthy donors. Patient MSCs comparatively exhibited i) senescence in culture; ii) similar osteogenic and adipogenic differentiation potential; iii) decreased expression of CD105, CD73, CD44, and HLA-A/B/C molecules; iv) distinct transcription at pre-AHSCT compared with control MSCs, yielding 618 differentially expressed genes, including the downregulation of TGFB1 and HGF genes and modulation of the FGF and HGF signaling pathways; v) reduced antiproliferative effects when pre-AHSCT MSCs were cocultured with allogeneic T-lymphocytes; vi) decreased secretion of IL-10 and TGF-ß in supernatants of both cocultures (pre- and post-AHSCT MSCs); and vii) similar percentages of regulatory cells recovered after MSC cocultures. The transcriptional profile of patient MSCs isolated 6 months posttransplantation was closer to pre-AHSCT samples than from healthy MSCs. Considering that patient MSCs exhibited phenotypic changes, distinct transcriptional profile and functional defects implicated in MSC immunomodulatory and immunosuppressive activity, we suggest that further MS clinical studies should be conducted using allogeneic bone marrow MSCs derived from healthy donors. We also demonstrated that treatment of MS patients with AHSCT does not reverse the transcriptional and functional alterations observed in patient MSCs.

Hydroxycarbamide modulates components involved in the regulation of adenosine levels in blood cells from sickle-cell anemia patients.

Recent studies have demonstrated the role of adenosine (ADO) in sickle-cell anemia (SCA). ADO is produced by CD39 and CD73 and converted to inosine by adenosine deaminase (ADA). We evaluated the effects of hydroxycarbamide (HU) treatment on the modulation of adenosine levels in SCA patients. The expressions of CD39, CD73, and CD26 were evaluated by flow cytometry on blood cells in 15 HU-treated and 17 untreated patients and 10 healthy individuals. RNA was extracted from monocytes, and ADA gene expression was quantified by real-time PCR. ADA activity was also evaluated. We found that ADA transcripts were two times higher in monocytes of HU-treated patients, compared with untreated (P = 0.039). Monocytes of HU-treated patients expressed CD26, while monocytes of controls and untreated patients did not (P = 0.023). In treated patients, a lower percentage of T lymphocytes expressed CD39 compared with untreated (P = 0.003), and the percentage of T regulatory (Treg) cells was reduced in the treated group compared with untreated (P = 0.017) and controls (P = 0.0009). Besides, HU-treated patients displayed increased ADA activity, compared with untreated. Our results indicate a novel mechanism of action of HU mediated by the reduction of adenosine levels and its effects on pathophysiological processes in SCA.

Maturation of human iDCs by IL-18 plus PGE2, but not by each stimulus alone, induced migration toward CCL21 and the secretion of IL-12 and IFN-γ.

Dendritic cells (DCs) are potent antigen-presenting cells that initiate the primary immune response and whose functional properties in vivo depend on the maturation stimulus. We describe the functional properties of human monocyte-derived DCs after the maturation of immature DCs (iDCs) for 2 days with LPS (100 ng/ml), PGE2 (1 µg/ml), CD40L (1 µg/ml) or IL-18 (200 ng/ml) and with CD40L+PGE2 and IL-18+PGE2 mixtures at the same concentrations as above. Neither IL-18 nor PGE2 alone stimulated IL-12 or IFN-γ secretion. When administered simultaneously to 1×10(6)iDCs/ml, IL-18+PGE2 induced the secretion of 131.4±6.7 pg IL-12/ml and 355±87 pg IFN-γ/ml but there was no detectable IL-10 secretion. However, PGE2 alone stimulated the secretion of 208±89 pg IL-10/ml whereas IL-18 alone did not stimulate the secretion of IL-10, IL-12, TNF-α or INF-γ. When the mixture of CD40L+PGE2 was used, only migration toward CCL19 and CCL21 was induced. CD40L did not stimulate the secretion of IL-10, IL-12, TNF-α or IFN-γ and did not stimulate migration toward CCL19 or CCL21. The extent of stimulation of T cell proliferation was essentially the same for all stimuli at the concentrations given above. New properties such as IL-12 and INF-γ secretion and migration toward CCL21 emerged when a mixture of IL-18+PGE2 was employed. These data show that when the pairs of stimuli reported here were used simultaneously their effect was not additive. This system can be used to prepare mDCs with properties useful for cell therapy and also as a model to investigate the mechanisms of cytokine secretion and cell migration.

Deregulation of apoptosis-related genes is associated with PRV1 overexpression and JAK2 V617F allele burden in Essential Thrombocythemia and Myelofibrosis.

BACKGROUND: Essential Thrombocythemia (ET) and Primary Myelofibrosis (PMF) are Chronic Myeloproliferative Neoplasms (MPN) characterized by clonal myeloproliferation/myeloaccumulation without cell maturation impairment. The JAK2 V617F mutation and PRV1 gene overexpression may contribute to MPN physiopathology. We hypothesized that deregulation of the apoptotic machinery may also play a role in the pathogenesis of ET and PMF. In this study we evaluated the apoptosis-related gene and protein expression of BCL2 family members in bone marrow CD34+ hematopoietic stem cells (HSC) and peripheral blood leukocytes from ET and PMF patients. We also tested whether the gene expression results were correlated with JAK2 V617F allele burden percentage, PRV1 overexpression, and clinical and laboratory parameters. RESULTS: By real time PCR assay, we observed that A1, MCL1, BIK and BID, as well as A1, BCLW and BAK gene expression were increased in ET and PMF CD34+ cells respectively, while pro-apoptotic BAX and anti-apoptotic BCL2 mRNA levels were found to be lower in ET and PMF CD34+ cells respectively, in relation to controls. In patients' leukocytes, we detected an upregulation of anti-apoptotic genes A1, BCL2, BCL-XL and BCLW. In contrast, pro-apoptotic BID and BIMEL expression were downregulated in ET leukocytes. Increased BCL-XL protein expression in PMF leukocytes and decreased BID protein expression in ET leukocytes were observed by Western Blot. In ET leukocytes, we found a correlation between JAK2 V617F allele burden and BAX, BIK and BAD gene expression and between A1, BAX and BIK and PRV1 gene expression. A negative correlation between PRV1 gene expression and platelet count was observed, as well as a positive correlation between PRV1 gene expression and splenomegaly. CONCLUSIONS: Our results suggest the participation of intrinsic apoptosis pathway in the MPN physiopathology. In addition, PRV1 and JAK2 V617F allele burden were linked to deregulation of the apoptotic machinery.

Human hepatic stellate cell line (LX-2) exhibits characteristics of bone marrow-derived mesenchymal stem cells.

The LX-2 cell line has characteristics of hepatic stellate cells (HSCs), which are considered pericytes of the hepatic microcirculatory system. Recent studies have suggested that HSCs might have mesenchymal origin. We have performed an extensive characterization of the LX-2 cells and have compared their features with those of mesenchymal cells. Our data show that LX-2 cells have a phenotype resembling activated HSCs as well as bone marrow-derived mesenchymal stem cells (BM-MSCs). Our immunophenotypic analysis showed that LX-2 cells are positive for activated HSC markers (αSMA, GFAP, nestin and CD271) and classical mesenchymal makers (CD105, CD44, CD29, CD13, CD90, HLA class-I, CD73, CD49e, CD166 and CD146) but negative for the endothelial marker CD31 and endothelial progenitor cell marker CD133 as well as hematopoietic markers (CD45 and CD34). LX-2 cells also express the same transcripts found in immortalized and primary BM-MSCs (vimentin, annexin 5, collagen 1A, NG2 and CD140b), although at different levels. We show that LX-2 cells are capable to differentiate into multilineage mesenchymal cells in vitro and can stimulate new blood vessel formation in vivo. LX-2 cells appear not to possess tumorigenic potential. Thus, the LX-2 cell line behaves as a multipotent cell line with similarity to BM-MSCs. This line should be useful for further studies to elucidate liver regeneration mechanisms and be the foundation for development of hepatic cell-based therapies.

A DNA vaccine candidate encoding the structural prM/E proteins elicits a strong immune response and protects mice against dengue-4 virus infection.

A DNA vaccine expressing dengue-4 virus premembrane (prM) and envelope (E) genes was produced by inserting these genes into a mammalian expression plasmid (pCI). Following a thorough screening, including confirmation of protein expression in vitro, a recombinant clone expressing these genes was selected and used to immunize BALB/c mice. After 3 immunizations all the animals produced detectable levels of neutralizing antibodies against dengue-4 virus. The cytokines levels and T cell proliferation, detected ex vivo from the spleen of the immunized mice, showed that our construction induced substantial immune stimulation after three doses. Even though the antibody levels, induced by our DNA vaccine, were lower than those obtained in mice immunized with dengue-4 virus the levels of protection were high with this vaccine. This observation is further supported by the fact that 80% of the vaccine immunized group was protected against lethal challenge. In conclusion, we developed a DNA vaccine employing the genes of the prM and E proteins from dengue-4 virus that protects mice against this virus.

Maturation of dendritic cells following exposure to different maturational stimuli / Maturação das células dendríticas após exposição a diversos estímulos

Dendritic cells (DCs) are professional antigen-presenting cells that are highly effective to immunize against pathogens and tumor antigens. In order to obtain mature DCs several in vitro methods have been reported. Selecting the most efficient and effective method of generating morphologic and phenotypic DCs within 7 days of culture is an essential prerequisite for success in immunotherapy strategies. Herein, we report a method of obtaining an enriched monocyte population from blood donors and performed a comparison of DC maturation in response to four agents. Monocyte populations with 91 percent ± 5 of purity were obtained from 15 healthy donors. The resulting monocyte populations were cultured in the presence of GM-CSF and IL-4 during 5 days. At day 5 different maturation conditions were performed and morphological and phenotypical changes were analyzed. Our study demonstrates that TNF-alpha or PGE1 by themselves can induce the expression of CD1a 2.4 and 2.7 times respectively more than DC cultures in the absence of maturing agents. On the other hand, for other costimulatory or accessory molecules (CD80, CD86, CD83 and CD40) TNF-alpha was more potent in the induction of expression than PGE1, although in the presence of TNF-alpha plus PGE1 this effect is more pronounced compared to TNF-alpha alone. Under TNF-alpha plus PGE1 treatment the phenotypical maturation of immature DCs are comparable to LPS and therefore TNF-alpha+ PGE1 might be useful for generating ex-vivo DCs to use in protocols of cell vaccination. Further functional evaluation of these mature DCs is warranted.

Células dendríticas (CDs) são células apresentadoras de antígenos altamente eficientes para a imunização contra patógenos e antígenos tumorais. A obtenção de CDs maturis tem sido descrita por diferentes métodos. Portanto, a escolha do método mais apropriado para gerar CDs em cultura de sete dias é pré-requisito essencial para as estratégias imunoterápicas. Aqui relatamos um método de obtenção de uma população enriquecida em monócitos de doadores de sangue e comparamos a maturação das CDs sob o estímulo de quatro agentes. Uma população de monócitos, com pureza de 91 por cento ± 5, foi obtida de 15 doadores. A população monocitária foi mantida em cultura por cinco dias com GM- CSF e IL - 4. No 5° dia, após diferentes condições de maturação, foram analisadas as modificações morfológicas e fenotípicas. Nossos estudos demonstram que o TNF-alfa ou o PGE1 por si só podem induzir a expressão de CD1a de 2.4 a 2.7 vezes, respectivamente, mais do que culturas de CDs com ausência dos agentes de maturação. Alternativamente, para com outras moléculas coestimuladoras ou acessórias (CD80, CD86, CD83 e CD 40) o TNF-alfa foi mais potente na expressão do que o PGE1, embora na presença de ambos o efeito seja mais pronunciado. A maturação fenotípica sob TNF-alfa + PGE1 pode ser comparável ao LPS, concluindo que o TNF-alfa + PGE1 pode ser útil para geração ex-vivo de CDs e útil para protocolos de vacinação celular. Avaliação funcional das CDs é recomendável.