Elaboración de un kit de separación magnética de células CD3+

Las técnicas de separación magnética son cada vez más importantes, con un amplio rango de aplicaciones en el campo de la biomedicina. La propiedad más notable y atractiva de los materiales magnéticos es que pueden ser aislados de una solución al aplicar un campo magnético externo. El principal objetivo de este proyecto es desarrollar un kit de separación celular utilizando nanopartículas magnéticas (NPm) de Gennova, conjugadas con el anticuerpo anti-CD3 (marcador específico de linfocitos T). Este proceso se realizará mediante la metodología AUTOMACS de Miltenyi. Tomando como referencia los resultados obtenidos por este método, intentaremos mejorarlo utilizando las NPm de Gennova. La primera tarea realizada en este proyecto es la activación de las NP. Partimos de NPm de 100nm, cubiertas por una matriz de polímeros con grupos terminales hidroxilos. Estas NPm deben ser funcionales y para ello son activadas con un novedoso reactivo de Gennova, denominado Smart-Link. Una vez activadas, pueden ser conjugadas con anticuerpos (en nuestro caso anti-CD3). Se utiliza un protocolo de acoplamiento que permite que el anticuerpo se una al reactivo Smart-Link por la región Fb, para que así la región Fab pueda reconocer el marcador celular de interés. A partir de este momento el complejo estará listo para su aplicación. La suspensión celular se obtiene de una cantidad de sangre concentrada (Buffy Coat). Realizaremos una separación en gradiente de densidad utilizando Ficoll para extraer las células mononucleares (nos interesan los linfocitos T). Los linfocitos T expresan en su superficie CD3. Al incubar las células con las NPm conjugadas con anticuerpos, se producirá la unión de ambas, ya que el anticuerpo reconocería al marcador de superficie celular. La separación magnética se realiza utilizando un equipo denominado AUTOMACS. Este dispositivo recoge toda la suspensión celular y separa las células en una fracción positiva (linfocitos T) y una fracción negativa (resto de células), usando un campo magnético. Nos quedaremos con la fracción positiva y realizaremos un recuento celular en la cámara de Neubauer para conocer la cantidad de células separadas. A día de hoy aún no se han obtenido resultados concluyentes pero en un futuro próximo se espera conseguir una separación eficiente de linfocitos T con el uso de las NPm de Gennova y así poder desarrollar el Kit de separación celular correspondiente

Sensitivity of hematopoietic stem cells to mitochondrial dysfunction by SdhD gene deletion

It is established that hematopoietic stem cells (HSC) in the hypoxic bone marrow have adapted their metabolism to oxygen-limiting conditions. This adaptation includes suppression of mitochondrial activity, induction of anerobic glycolysis, and activation of hypoxia-inducible transcription factor 1α (Hif1α)-dependent gene expression. During progression of hematopoiesis, a metabolic switch towards mitochondrial oxidative phosphorylation is observed, making this organelle essential for determining cell fate choice in bone marrow. However, given that HSC metabolism is essentially oxygen-independent, it is still unclear whether functional mitochondria are absolutely required for their survival. To assess the actual dependency of these undifferentiated cells on mitochondrial function, we have performed an analysis of the hematopoiesis in a mouse mutant, named SDHD-ESR, with inducible deletion of the mitochondrial protein-encoding SdhD gene. This gene encodes one of the subunits of the mitochondrial complex II (MCII). In this study, we demonstrate that, in contrast to what has been previously established, survival of HSC, and also myeloid and B-lymphoid progenitors, depends on proper mitochondrial activity. In addition, gene expression analysis of these hematopoietic lineages in SDHD-ESR mutants calls into question the proposed activation of Hif1α in response to MCII dysfunction.Ministerio de Ciencia e Innovación SAF2009-06970Junta de Andalucía CTS-4589Instituto de Salud Carlos III PI-0355-201

Role of drug transporters in the sensitivity of acute myeloid leukemia to sorafenib

[EN]Chemoresistance often limits the success of the pharmacological treatment in acute myeloid leukemia (AML) patients. Although positive results have been obtained with tyrosine kinase inhibitors (TKIs), such as sorafenib, especially in patients with Fms-like tyrosine kinase 3 (FLT3)-positive AML, the success of chemotherapy is very heterogeneous.The sensitivity to sorafenib-induced cell death (MTT test and anexin V/7-AAD method) was evaluated in five different cell lines: MOLM-13, OCI-AML2, HL-60, HEL and K-562. The transportome was characterized by measuring mRNA using RT-qPCR. Drug uptake/efflux was determined by flow cytometry using specific substrates and inhibitors. The cytostatic response to sorafenib was: MOLM-13»OCI-AML2>HL- 60>HEL≈K-562. Regarding efflux pumps, MDR1 was highly expressed in HEL>K- 562≈MOLM-13, but not in OCI-AML2 and HL-60. BCRP and MPR3 expression was low in all cell lines, whereas MRP4 and MRP5 expression was from moderate to high. Flow cytometry studies demonstrated that MRP4, but not MRP5, was functional

Selection of Tumor-Specific Cytotoxic T Lymphocytes in Acute Myeloid Leukemia Patients Through the Identification of T-Cells Capable to Establish Stable Interactions With the Leukemic Cells: “Doublet Technology”

The relevance of the immune system in cancer has long been studied. Autologous adoptive T cell therapies, based on the use of tumor infiltrating lymphocytes (TILs), have made great progress in recent years for the treatment of solid tumors, especially melanoma. However, further work is needed to isolate tumor-reactive T cells among patients diagnosed with hematologic malignancies. The dynamics of the interaction between T cells and antigen presenting cells (APC) dictate the quality of the immune responses. While stable joints between target cells and T lymphocytes lead to the induction of T cell activation and immune response, brief contacts contribute to the induction of immune-tolerance. Taking advantage of the strong interaction between target cell and activated T-cells, we show the feasibility to identify and isolate tumor-specific cytotoxic T lymphocytes (CTLs) from acute myeloid leukemia (AML) patients by flow cytometry. Using this technology, CTLs bound through T cell receptor (TCR) to tumor cells can be identified in peripheral blood and bone marrow and subsequently selected and isolated by FACS-based cell sorting. These CTLs display higher percentage of effector cells and marked cytotoxic activity against AML blasts. In conclusion, we have developed a new procedure to identify and select specific cytotoxic T cells in patients diagnosed with acute myeloid leukemia.Instituto de Salud Carlos III PFIS-FI12/00189Instituto de Salud Carlos III ISCIII PI14/02074Instituto de Salud Carlos III PI11/02366Instituto de Salud Carlos III PI17/02177European Union (ERDF/ESF, Investing in your future)CIBER CB16/12/0048

Biocompatibility of two model elastin‐like recombinamer‐based hydrogels formed through physical or chemical cross‐linking for various applications in tissue engineering and regenerative medicine

Producción CientíficaBiocompatibility studies, especially innate immunity induction, in vitro and in vivo cytotoxicity, and fibrosis, are often lacking for many novel biomaterials including recombinant protein‐based ones, such as elastin‐like recombinamers (ELRs), and has not been extensively explored in the scientific literature, in contrast to traditional biomaterials. Herein, we present the results from a set of experiments designed to elucidate the preliminary biocompatibility of 2 types of ELRs that are able to form extracellular matrix‐like hydrogels through either physical or chemical cross‐linking both of which are intended for different applications in tissue engineering and regenerative medicine. Initially, we present in vitro cytocompatibility results obtained upon culturing human umbilical vein endothelial cells on ELR substrates, showing optimal proliferation up to 9 days. Regarding in vivo cytocompatibility, luciferase‐expressing hMSCs were viable for at least 4 weeks in terms of bioluminescence emission when embedded in ELR hydrogels and injected subcutaneously into immunosuppressed mice. Furthermore, both types of ELR‐based hydrogels were injected subcutaneously in immunocompetent mice and serum TNFα, IL‐1β, IL‐4, IL‐6, and IL‐10 concentrations were measured by enzyme‐linked immunosorbent assay, confirming the lack of inflammatory response, as also observed upon macroscopic and histological evaluation. All these findings suggest that both types of ELRs possess broad biocompatibility, thus making them very promising for tissue engineering and regenerative medicine‐related applications.European Commission (NMP-2014-646075, HEALTH-F4-2011-278557, PITN-GA-2012-317306 and MSCA-ITN-2014-642687)Ministerio de Economía, Industria y Competitividad (Projects MAT2016-78903-R, MAT2016-79435-R, MAT2013-42473-R, MAT2013-41723-R and MAT2012-38043)Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref.VA244U13 and VA313U14)Centro en Red de Medicina Regenerativa y Terapia Celular de Castilla y LeónInstituto de Salud Carlos III (grant RD12/0019/0017 )Fundação para a Ciência e Tecnologia (SFRH/BD/86451/ 2012

Human Bone Marrow Stromal Cells Differentiate Into Corneal Tissue and Prevent Ocular Graft-Versus-Host Disease in Mice

Clinical trials have assessed the use of human bone marrow stromal cells (hBMSCs) for the treatment of immune-related disorders such as graft-versus-host disease (GVHD). In the current study, we show that GFP+-transduced hBMSCs generated from bone marrow migrate and differentiate into corneal tissue after subconjunctival injection in mice. Interestingly, these hBMSCs display morphological features of epithelial, stromal, and endothelial cells and appear at different layers and with different morphologies depending on their position within the epithelium. Furthermore, these cells display ultrastructural properties, such as bundles of intermediate filaments, interdigitations, and desmosomes with GFP- cells, which confirms their differentiation into corneal tissues. GFP+-transduced hBMSCs were injected at different time points into the right eye of lethally irradiated mice undergoing bone marrow transplantation, which developed ocular GVHD (oGVHD). Remarkably, hBMSCs massively migrate to corneal tissues after subconjunctival injection. Both macroscopic and histopathological examination showed minimal or no evidence of GVHD in the right eye, while the left eye, where no hBMSCs were injected, displayed features of GVHD. Thus, in the current study, we confirm that hBMSCs may induce their therapeutic effect at least in part by differentiation and regeneration of damaged tissues in the host. Our results provide experimental evidence that hBMSCs represent a potential cellular therapy to attenuate oGVHD

Caspase-8 inhibition represses initial human monocyte activation in septic shock model

In septic patients, the onset of septic shock occurs due to the over-activation of monocytes. We tested the therapeutic potential of directly targeting innate immune cell activation to limit the cytokine storm and downstream phases. We initially investigated whether caspase-8 could be an appropriate target given it has recently been shown to be involved in microglial activation. We found that LPS caused a mild increase in caspase-8 activity and that the caspase-8 inhibitor IETD-fmk partially decreased monocyte activation. Furthermore, caspase-8 inhibition induced necroptotic cell death of activated monocytes. Despite inducing necroptosis, caspase-8 inhibition reduced LPS-induced expression and release of IL-1β and IL-10. Thus, blocking monocyte activation has positive effects on both the pro and anti-inflammatory phases of septic shock. We also found that in primary mouse monocytes, caspase-8 inhibition did not reduce LPS-induced activation or induce necroptosis. On the other hand, broad caspase inhibitors, which have already been shown to improve survival in mouse models of sepsis, achieved both. Thus, given that monocyte activation can be regulated in humans via the inhibition of a single caspase, we propose that the therapeutic use of caspase-8 inhibitors could represent a more selective alternative that blocks both phases of septic shock at the source.Unión Europea, Ministerio de Economía y Competitividad SAF2012-39029Unión Europea, Ministerio de Economía y Competitividad SAF2015-64171REspaña,Junta de Andalucía P10-CTS-649

Mesenchymal stromal cells (MSC) from JAK2+ myeloproliferative neoplasms differ from normal MSC and contribute to the maintenance of neoplastic hematopoiesis

[EN]There is evidence of continuous bidirectional cross-talk between malignant cells and bone marrow-derived mesenchymal stromal cells (BM-MSC), which favors the emergence and progression of myeloproliferative neoplastic (MPN) diseases. In the current work we have compared the function and gene expression profile of BM-MSC from healthy donors (HDMSC) and patients with MPN (JAK2V617F), showing no differences in the morphology, proliferation and differentiation capacity between both groups. However, BM-MSC from MPN expressed higher mean fluorescence intensity (MIF) of CD73, CD44 and CD90, whereas CD105 was lower when compared to controls. Gene expression profile of BM-MSC showed a total of 169 genes that were differentially expressed in BM-MSC from MPN patients compared to HD-MSC. In addition, we studied the ability of BM-MSC to support the growth and survival of hematopoietic stem/progenitor cells (HSPC), showing a significant increase in the number of CFU-GM colonies when MPN-HSPC were co-cultured with MPN-MSC. Furthermore, MPN-MSC showed alteration in the expression of genes associated to the maintenance of hematopoiesis, with an overexpression of SPP1 and NF-kB, and a downregulation of ANGPT1 and THPO. Our results suggest that BM-MSC from JAK2+ patients differ from their normal counterparts and favor the maintenance of malignant clonal hematopoietic cell

Cannabinoid derivatives exert a potent anti-myeloma activity both in vitro and in vivo

12 p.-6 fig.-1 tab.Although hematopoietic and immune system show high levels of the cannabinoid receptor CB2, the potential effect of cannabinoids on hematologic malignancies has been poorly determined. Here we have investigated their anti-tumor effect in multiple myeloma (MM). We demonstrate that cannabinoids induce a selective apoptosis in MM cell lines and in primary plasma cells of MM patients, while sparing normal cells from healthy donors, including hematopoietic stem cells. This effect was mediated by caspase activation, mainly caspase-2, and was partially prevented by a pan-caspase inhibitor. Their pro-apoptotic effect was correlated with an increased expression of Bax and Bak, a decrease of Bcl-xL and Mcl-1, a biphasic response of Akt/PKB and an increase in the levels of ceramide in MM cells. Inhibition of ceramide synthesis partially prevented apoptosis, indicating that these sphingolipids play a key role in the pro-apoptotic effect of cannabinoids in MM cells. Remarkably, blockage of the CB2 receptor also inhibited cannabinoid-induced apoptosis. Cannabinoid derivative WIN-55 enhanced the anti-myeloma activity of dexamethasone and melphalan overcoming resistance to melphalan in vitro. Finally, administration of cannabinoid WIN-55 to plasmacytoma-bearing mice significantly suppressed tumor growth in vivo. Together, our data suggest that cannabinoids may be considered as potential therapeutic agents in the treatment of MM.Grant sponsor: Junta de Andalucía; Grant numbers: PI-0355–2013 and AC-0062–2013; Grant sponsor: Instituto de Salud Carlos III;Grant numbers: PI14/02074 and CP12/03273.Peer reviewe

Depletion of alloreactive T-cells in vitro using the proteasome inhibitor bortezomib preserves the immune response against pathogens

Current graft-versus-host disease (GVHD) inhibition approaches lead to abrogation of pathogen-specific T-cell responses. We propose an approach to inhibit GVHD without hampering immunity against pathogens: in vitro depletion of alloreactive T cells with the preoteasome inhibitor bortezomib. We show that PBMCs stimulated with allogeneic cells and treated with bortezomib greatly reduce their ability to produce IFN-γ when re-stimulated with the same allogeneic cells, but mainly preserve their ability to respond to citomegalovirus stimulation. Unlike in vivo administration of immunosuppressive drugs or other strategies of allodepletion, in vitro allodepletion with bortezomib maintains pathogen-specific T cells, representing a promising alternative for GVHD prophylaxis. © 2011 Elsevier Ltd.Belén Blanco was supported by a fellowship from the Fondo de Investigación Sanitaria and by a grant of Gerencia Regional de Salud de Castilla y León.Peer Reviewe