Multi-component cord blood banking: a proof-of-concept international exercise.

BACKGROUND: Most public cord blood (CB) banks currently discard more than 80% of umbilical CB units not suitable for hemopoietic stem cell transplant due to low stem cell count. Although CB platelets, plasma, and red blood cells have been used for experimental allogeneic applications in wound healing, corneal ulcer treatment, and neonatal transfusion, no standard procedures for their preparation have been defined internationally. MATERIALS AND METHODS: A network of 12 public CB banks in Spain, Italy, Greece, the UK, and Singapore developed a protocol to validate a procedure for the routine production of CB platelet concentrate (CB-PC), CB platelet-poor plasma (CB-PPP), and CB leukoreduced red blood cells (CB-LR-RBC) using locally available equipment and the commercial BioNest ABC and EF medical devices. CB units with >50 mL volume (excluding anticoagulant) and ≥150×109/L platelets were double centrifuged to obtain CB-PC, CB-PPP, and CB-RBC. The CB-RBC were diluted with saline-adenine-glucose-mannitol (SAGM), leukoreduced by filtration, stored at 2-6°C, and tested for hemolysis and potassium (K+) release over 15 days, with gamma irradiation performed on day 14. A set of acceptance criteria was pre-defined. This was for CB-PC: volume ≥5 mL and platelet count 800-1,200×109/L; for CB-PPP: platelet count <50×109/L; and for CB-LR-RBC: volume ≥20 mL, hematocrit 55-65%, residual leukocytes <0.2×106/unit, and hemolysis ≤0.8%. RESULTS: Eight CB banks completed the validation exercise. Compliance with acceptance criteria was 99% for minimum volume and 86.1% for platelet count in CB-PC, and 90% for platelet count in CB-PPP. Compliance in CB-LR-RBC was 85.7% for minimum volume, 98.9% for residual leukocytes, and 90% for hematocrit. Compliance for hemolysis ≤0.8% decreased from 89.0 to 63.2% from day 0 to 15. K+ release increased from 3.0±1.8 to 25.0±7.0 mmol/L from day 0 to 15, respectively. DISCUSSION: The MultiCord12 protocol was a useful tool to develop preliminary standardization of CB-PC, CB-PPP, and CB-LR-RBC.

Optimal large-scale CD34+ enrichment from a leukapheresis collection using the clinimacs prodigy platform.

Optimization of Hematology Patient's treatment: It is possible to obtain a 100% CD34+ recovery after CD34+ selection using the CliniMACS Prodigy.

Impaired LXRα Phosphorylation Attenuates Progression of Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) is a very common indication for liver transplantation. How fat-rich diets promote progression from fatty liver to more damaging inflammatory and fibrotic stages is poorly understood. Here, we show that disrupting phosphorylation at Ser196 (S196A) in the liver X receptor alpha (LXRα, NR1H3) retards NAFLD progression in mice on a high-fat-high-cholesterol diet. Mechanistically, this is explained by key histone acetylation (H3K27) and transcriptional changes in pro-fibrotic and pro-inflammatory genes. Furthermore, S196A-LXRα expression reveals the regulation of novel diet-specific LXRα-responsive genes, including the induction of Ces1f, implicated in the breakdown of hepatic lipids. This involves induced H3K27 acetylation and altered LXR and TBLR1 cofactor occupancy at the Ces1f gene in S196A fatty livers. Overall, impaired Ser196-LXRα phosphorylation acts as a novel nutritional molecular sensor that profoundly alters the hepatic H3K27 acetylome and transcriptome during NAFLD progression placing LXRα phosphorylation as an alternative anti-inflammatory or anti-fibrotic therapeutic target.

Granulocyte-derived TNFα promotes vascular and hematopoietic regeneration in the bone marrow.

Endothelial cells are a critical component of the bone marrow (BM) stromal network, which maintains and regulates hematopoietic cells. Vascular regeneration precedes, and is necessary for, successful hematopoietic stem cell (HSC) transplantation, the only cure for most hematopoietic diseases. Recent data suggest that mature hematopoietic cells regulate BM stromal-cell function. Whether a similar cross-talk regulates the BM vasculature is not known. Here we found that donor hematopoietic cells act on sinusoidal endothelial cells and induce host blood vessel and hematopoietic regeneration after BM transplantation in mice. Adoptive transfer of BM, but not peripheral, granulocytes prevented the death of mice transplanted with limited numbers of HSCs and accelerated recovery of host vessels and hematopoietic cells. Moreover, selective granulocyte ablation in vivo impaired vascular and hematopoietic regeneration after BM transplantation. Gene expression analyses indicated that granulocytes are the main source of the cytokine TNFα, whereas its receptor TNFR1 is selectively upregulated in regenerating blood vessels. In adoptive transfer experiments, wild type, but not Tnfa-/-, granulocytes induced vascular recovery, and wild-type granulocyte transfer did not prevent death or promote vascular regeneration in Tnfr1-/-; Tnfr2-/- mice. Thus, by delivering TNFα to endothelial cells, granulocytes promote blood vessel growth and hematopoietic regeneration. Manipulation of the cross-talk between granulocytes and endothelial cells may lead to new therapeutic approaches to improve blood vessel regeneration and increase survival and hematopoietic recovery after HSC transplantation.

BKV-specific T cells in the treatment of severe refractory haemorrhagic cystitis after HLA-haploidentical haematopoietic cell transplantation.

BACKGROUND: Haemorrhagic cystitis caused by BK virus (BKV) is a known complication of allogeneic haematopoietic cell transplantation (HCT) and is relatively common following HLA-haploidentical transplantation. Adoptive immunotransfer of virus-specific T cells from the donor is a promising therapeutic approach, although production of these cells is challenging, particularly when dealing with low-frequency T cells such as BKV-specific T cells. CASE REPORT: Here, we present a patient who, following haploidentical HCT, developed severe BKV haemorrhagic cystitis, resistant to standard therapy. He responded well to adoptive transfer of donor cells enriched in BKV-specific T cells using the new second-generation CliniMACS Prodigy and the Cytokine Capture System from Miltenyi Biotec. Treatment led to full resolution of both the symptoms and viraemia without unwanted complications. CONCLUSION: Our observations suggest that use of products enriched with BKV-specific T cells generated using this system is safe and efficient in HLA-haploidentical HCT where BKV cystitis can be a serious complication.

Macrophages and c-Myc cross paths.

The c-Myc transcription factor has recently been proposed as a bona fide M2 macrophage marker. Although this finding represents a major step forward in the identification of different macrophage subsets, it also opens up the potential for speculation concerning the possible functions of c-Myc in macrophages and the implications for health and disease.

The nuclear receptor LXR modulates interleukin-18 levels in macrophages through multiple mechanisms.

IL-18 is a member of the IL-1 family involved in innate immunity and inflammation. Deregulated levels of IL-18 are involved in the pathogenesis of multiple disorders including inflammatory and metabolic diseases, yet relatively little is known regarding its regulation. Liver X receptors or LXRs are key modulators of macrophage cholesterol homeostasis and immune responses. Here we show that LXR ligands negatively regulate LPS-induced mRNA and protein expression of IL-18 in bone marrow-derived macrophages. Consistent with this being an LXR-mediated process, inhibition is abolished in the presence of a specific LXR antagonist and in LXR-deficient macrophages. Additionally, IL-18 processing of its precursor inactive form to its bioactive state is inhibited by LXR through negative regulation of both pro-caspase 1 expression and activation. Finally, LXR ligands further modulate IL-18 levels by inducing the expression of IL-18BP, a potent endogenous inhibitor of IL-18. This regulation occurs via the transcription factor IRF8, thus identifying IL-18BP as a novel LXR and IRF8 target gene. In conclusion, LXR activation inhibits IL-18 production through regulation of its transcription and maturation into an active pro-inflammatory cytokine. This novel regulation of IL-18 by LXR could be applied to modulate the severity of IL-18 driven metabolic and inflammatory disorders.

Isolation, Culture, and Polarization of Murine Bone Marrow-Derived and Peritoneal Macrophages.

Macrophages are the most specialized phagocytic cells, and acquire specific phenotypes and functions in response to a variety of external triggers. Culture of bone marrow-derived or peritoneal macrophages from mice represents an exceptionally powerful technique to investigate macrophage phenotypes and functions in response to specific stimuli, resembling as much as possible the conditions observed in various pathophysiological settings. This chapter outlines protocols used to isolate and culture murine bone marrow-derived and peritoneal macrophages. Furthermore, we describe how these macrophages can be "polarized" to obtain specific macrophage subsets with special relevance to atherosclerosis.

Nitric oxide prevents aortic neointimal hyperplasia by controlling macrophage polarization.

OBJECTIVE: Nitric oxide synthase 3 (NOS3) prevents neointima hyperplasia by still unknown mechanisms. To demonstrate the significance of endothelial nitric oxide in the polarization of infiltrated macrophages through the expression of matrix metalloproteinase (MMP)-13 in neointima formation. APPROACH AND RESULTS: After aortic endothelial denudation, NOS3 null mice show elevated neointima formation, detecting increased mobilization of LSK (lineage-negative [Lin]-stem-cell antigen 1 [SCA1]+KIT+) progenitor cells, and high ratios of M1 (proinflammatory) to M2 (resolving) macrophages, accompanied by high expression of interleukin-5, interleukin-6, MCP-1 (monocyte chemoattractant protein), VEGF (vascular endothelial growth factor), GM-CSF (granulocyte-macrophage colony stimulating factor), interleukin-1ß, and interferon-γ. In conditional c-Myc knockout mice, in which M2 polarization is defective, denuded aortas showed extensive wall thickening as well. Conditioned medium from NOS3-deficient endothelium induced extensive repolarization of M2 macrophages to an M1 phenotype, and vascular smooth muscle cells proliferated and migrated faster in conditioned medium from M1 macrophages. Among the different proteins participating in cell migration, MMP-13 was preferentially expressed by M1 macrophages. M1-mediated vascular smooth muscle cell migration was inhibited when macrophages were isolated from MMP-13-deficient mice, whereas exogenous administration of MMP-13 to vascular smooth muscle cell fully restored migration. Excess vessel wall thickening in mice lacking NOS3 was partially reversed by simultaneous deletion of MMP-13, indicating that NOS3 prevents neointimal hyperplasia by preventing MMP-13 activity. An excess of M1-polarized macrophages that coexpress MMP-13 was also detected in human carotid samples from endarterectomized patients. CONCLUSIONS: These findings indicate that at least M1 macrophage-mediated expression of MMP-13 in NOS3 null mice induces neointima formation after vascular injury, suggesting that MMP-13 may represent a new promising target in vascular disease.

Inhibition of MYC in macrophages: tumor vs inflammation-related diseases.

Inhibition of MYC has been postulated as one of the most promising anti-tumoral therapies. However, if some anti-inflammatory cells express MYC, would an anti-tumoral treatment targeting MYC facilitate subsequent inflammation-related disorders?

Role of c-MYC in tumor-associated macrophages and cancer progression.

Transcription factors of the MYC family regulate several homeostatic cell functions, and their role as proto-oncogenes has been the focus of interest for decades. We have recently demonstrated that c-MYC is expressed by tumor-associated macrophages (TAMs) and regulates their phenotype and pro-tumor activities in vivo.

Aryl hydrocarbon receptor contributes to the MEK/ERK-dependent maintenance of the immature state of human dendritic cells.

Dendritic cells (DCs) promote tolerance or immunity depending on their maturation state, which is enhanced or accelerated upon MEK-ERK signaling pathway inhibition. We have determined the contribution of MEK-ERK activation to the profile of gene expression of human immature monocyte-derived dendritic cells (MDDCs) and peripheral blood myeloid DCs. ERK inhibition altered the expression of genes that mediate Chemokine (C-C motif) ligand 19 (CCL19)-directed migration (CCR7) and low-density lipoprotein (LDL) binding (CD36, SCARB1, OLR1, CXCL16) by immature DCs. In addition, ERK upregulated CCL2 expression while impairing the expression of DC maturation markers (RUNX3, ITGB7, IDO1). MEK-ERK-regulated genes exhibited an overrepresentation of cognate sequences for the aryl hydrocarbon receptor (AhR) transcription factor, whose transcriptional and DNA-binding activities increased in MDDCs upon exposure to the MEK1/2 inhibitor U0126. Therefore, the MEK-ERK signaling pathway regulates antigen capture, lymph node homing, and acquisition of maturation-associated genes, and its contribution to the maintenance of the immature state of MDDCs and myeloid DCs is partly dependent on the activity of AhR. Since pharmacologic modulation of the MEK-ERK signaling pathway has been proposed as a potential therapeutic strategy for cancer, our findings indicate that ERK inhibitors might influence antitumor responses through regulation of critical DC effector functions.

Inactivation of nuclear factor-Y inhibits vascular smooth muscle cell proliferation and neointima formation.

OBJECTIVE: Atherosclerosis and restenosis are multifactorial diseases associated with abnormal vascular smooth muscle cell (VSMC) proliferation. Nuclear factor-Y (NF-Y) plays a major role in transcriptional activation of the CYCLIN B1 gene (CCNB1), a key positive regulator of cell proliferation and neointimal thickening. Here, we investigated the role of NF-Y in occlusive vascular disease. APPROACH AND RESULTS: We performed molecular and expression studies in cultured cells, animal models, and human tissues. We find upregulation of NF-Y and cyclin B1 expression in proliferative regions of murine atherosclerotic plaques and mechanically induced lesions, which correlates with higher binding of NF-Y to target sequences in the CCNB1 promoter. NF-YA expression in neointimal lesions is detected in VSMCs, macrophages, and endothelial cells. Platelet-derived growth factor-BB, a main inductor of VSMC growth and neointima development, induces the recruitment of NF-Y to the CCNB1 promoter and augments both CCNB1 mRNA expression and cell proliferation through extracellular signal-regulated kinase 1/2 and Akt activation in rat and human VSMCs. Moreover, adenovirus-mediated overexpression of a NF-YA-dominant negative mutant inhibits platelet-derived growth factor-BB-induced CCNB1 expression and VSMC proliferation in vitro and neointimal lesion formation in a mouse model of femoral artery injury. We also detect NF-Y expression and DNA-binding activity in human neointimal lesions. CONCLUSIONS: Our results identify NF-Y as a key downstream effector of the platelet-derived growth factor-BB-dependent mitogenic pathway that is activated in experimental and human vasculoproliferative diseases. They also identify NF-Y inhibition as a novel and attractive strategy for the local treatment of neointimal formation induced by vessel denudation.

Role of platelets as mediators that link inflammation and thrombosis in atherosclerosis.

Platelets, crucial mediators of the acute complications of atherosclerosis that cause life-threatening ischemic events at late stages of the disease, are also key effectors of inflammation throughout plaque development through their interaction with endothelial and immune cells in the injured vessel wall. During the first steps of atherosclerosis, blood inflammatory leukocytes interact with the damaged endothelium in areas rich in platelet aggregates. In late stages of the disease, platelets secrete several inflammatory molecules, even without forming aggregates. These molecules exacerbate the inflammation and induce the transition from chronic to acute disease, featuring increased instability of the atherosclerotic lesion that results in plaque rupture and thrombosis. Moreover, platelets play an important role in vascular wall remodeling induced by chronic inflammation by controlling vascular cell differentiation and proliferation. In this review, we discuss the role of platelets as cell mediators that link inflammation and thrombosis in atherosclerotic disease and their potential in the development of new therapeutic tools to fight cardiovascular disease.

In vivo inhibition of c-MYC in myeloid cells impairs tumor-associated macrophage maturation and pro-tumoral activities.

Although tumor-associated macrophages (TAMs) are involved in tumor growth and metastasis, the mechanisms controlling their pro-tumoral activities remain largely unknown. The transcription factor c-MYC has been recently shown to regulate in vitro human macrophage polarization and be expressed in macrophages infiltrating human tumors. In this study, we exploited the predominant expression of LysM in myeloid cells to generate c-Myc(fl/fl) LysM(cre/+) mice, which lack c-Myc in macrophages, to investigate the role of macrophage c-MYC expression in cancer. Under steady-state conditions, immune system parameters in c-Myc(fl/fl) LysM(cre/+) mice appeared normal, including the abundance of different subsets of bone marrow hematopoietic stem cells, precursors and circulating cells, macrophage density, and immune organ structure. In a model of melanoma, however, TAMs lacking c-Myc displayed a delay in maturation and showed an attenuation of pro-tumoral functions (e.g., reduced expression of VEGF, MMP9, and HIF1α) that was associated with impaired tissue remodeling and angiogenesis and limited tumor growth in c-Myc(fl/fl) LysM(cre/+) mice. Macrophage c-Myc deletion also diminished fibrosarcoma growth. These data identify c-Myc as a positive regulator of the pro-tumoral program of TAMs and suggest c-Myc inactivation as an attractive target for anti-cancer therapy.

Macrophage proliferation and apoptosis in atherosclerosis.

PURPOSE OF REVIEW: Atherosclerosis is driven by cardiovascular risk factors that cause the recruitment of circulating immune cells beneath the vascular endothelium. Infiltrated monocytes differentiate into different macrophage subtypes with protective or pathogenic activities in vascular lesions. We discuss current knowledge about the molecular mechanisms that regulate lesional macrophage proliferation and apoptosis, two processes that occur during atherosclerosis development and regulate the number and function of macrophages within the atherosclerotic plaque. RECENT FINDINGS: Lesional macrophages in early phases of atherosclerosis limit disease progression by phagocytizing modified lipoproteins, cellular debris and dead cells that accumulate in the plaque. However, macrophages in advanced lesions contribute to a maladaptive, nonresolving inflammatory response that can lead to life-threatening acute thrombotic diseases (myocardial infarction or stroke). Macrophage-specific manipulation of genes involved in cell proliferation and apoptosis modulates lesional macrophage accumulation and atherosclerosis burden in mouse models, and studies are beginning to elucidate the underlying mechanisms. SUMMARY: Despite recent advances in our understanding of macrophage proliferation and apoptosis in atherosclerotic plaques, it remains unclear whether manipulating these processes will be beneficial or harmful. Advances in these areas may translate into more efficient therapies for the prevention and treatment of atherothrombosis.

Role of c-MYC in alternative activation of human macrophages and tumor-associated macrophage biology.

In response to microenvironmental signals, macrophages undergo different activation, including the "classic" proinflammatory phenotype (also called M1), the "alternative" activation induced by the IL-4/IL-13 trigger, and the related but distinct heterogeneous M2 polarization associated with the anti-inflammatory profile. The latter is induced by several stimuli, including IL-10 and TGF-ß. Macrophage-polarized activation has profound effects on immune and inflammatory responses and in tumor biology, but information on the underlying molecular pathways is scarce. In the present study, we report that alternative polarization of macrophages requires the transcription factor c-MYC. In macrophages, IL-4 and different stimuli sustaining M2-like polarization induce c-MYC expression and its translocation to the nucleus. c-MYC controls the induction of a subset (45%) of genes associated with alternative activation. ChIP assays indicate that c-MYC directly regulates some genes associated with alternative activation, including SCARB1, ALOX15, and MRC1, whereas others, including CD209, are indirectly regulated by c-MYC. c-MYC up-regulates the IL-4 signaling mediators signal transducer and activator of transcription-6 and peroxisome proliferator-activated receptorγ, is also expressed in tumor-associated macrophages, and its inhibition blocks the expression of protumoral genes including VEGF, MMP9, HIF-1α, and TGF-ß. We conclude that c-MYC is a key player in alternative macrophage activation, and is therefore a potential therapeutic target in pathologies related to these cells, including tumors.