In Ataxia-Telangiectasia, Oral Betamethasone Administration Ameliorates Lymphocytes Functionality through Modulation of the IL-7/IL-7Rα Axis Paralleling the Neurological Behavior: A Comparative Report of Two Cases.

Ataxia-Telangiectasia (A-T) is characterized by cerebellar neurodegeneration and immunodeficiency. Recent studies suggest that very low glucocorticoids (GCs) doses may help improve A-T neurological phenotype in some patients. Interestingly, in GCs studies an unexpected improvement of lymphocytes proliferation in some A-T patients has been observed. GCs are able to upregulate IL-7 Rα expression and rescue it from the recycling. In this study, we compared several immunological functions, including PBMC proliferative responses, cell activation events and IL-7/IL-7 Rα axis functionality, with the neurological behavior during an in-vivo GCs treatment between the most Responder patient to GC and the Non-Responder at all. During in-vivo GC treatment, we observed an increase of lymphocyte proliferation upon stimulation with PHA or IL-7 only in the Responder. This finding paralleled the increase in the surface expression of IL-7 R and up-regulation of the CD69 T-cell activation marker. Internalization and recycling of IL-7 R occurred properly only in the Responder. Microarray analysis revealed a remarkable difference in the DE-genes levels among Responder and Non-Responder, mostly concerning miRNAs and Multiple Complex families. Our findings suggest that the improvement of lymphocyte functionality, which correlates to the neurological behavior, is mediated through an effect of GCs on the IL-7/IL-7 Rα axis.

Features, reason for testing, and changes with time of 583 paroxysmal nocturnal hemoglobinuria clones from 529 patients: a multicenter Italian study.

In this study, we aimed at disclosing the main features of paroxysmal nocturnal hemoglobinuria (PNH) clones, their association with presentation syndromes, and their changes during follow-up. A large-scale, cooperative collection (583 clones from 529 patients) of flow cytometric and clinical data was entered into a national repository. Reason for testing guidelines were provided to the 41 participating laboratories, which followed the 2010 technical recommendations for PNH testing by Borowitz. Subsequently, the 30 second-level laboratories adopted the 2012 guidelines for high-resolution PNH testing, both upon order by the local clinicians and as an independent laboratory initiative in selected cases. Type3 and Type2 PNH clones (total and partial absence of glycosyl-phosphatidyl-inositol-anchor, respectively) were simultaneously present in 54 patients. In these patients, Type3 component was sevenfold larger than Type2 (p < 0.001). Frequency distribution analysis of solitary Type3 clone size (N = 442) evidenced two discrete patterns: small (20% of peripheral neutrophils) and large (> 70%) clones. The first pattern was significantly associated with bone marrow failure and myelodysplastic syndromes, the second one with hemolysis, hemoglobinuria, and thrombosis. Pediatric patients (N = 34) showed significant preponderance of small clones and bone marrow failure. The majority of PNH clones involved neutrophils, monocytes, and erythrocytes. Nevertheless, we found clones made exclusively by white cells (N = 13) or erythrocytes (N = 3). Rare cases showed clonal white cells restricted only to monocytes (6 cases) or neutrophils (3 cases). Retesting over 1-year follow-up in 151 cases showed a marked clone size increase in 4 cases and a decrease in 13, demonstrating that early breaking-down of PNH clones is not a rare event (8.6% of cases). This collaborative nationwide study demonstrates a clear-cut difference in size between Type2 and Type3 clones, emphasizes the existence of just two classes of PNH presentations based on Type3 clone size, depicts an asymmetric cellular composition of PNH clones, and documents the possible occurrence of changes in clone size during the follow-up.

Lipopolysaccharide-Elicited TSLPR Expression Enriches a Functionally Discrete Subset of Human CD14+ CD1c+ Monocytes.

Thymic stromal lymphopoietin (TSLP) is a cytokine produced mainly by epithelial cells in response to inflammatory or microbial stimuli and binds to the TSLP receptor (TSLPR) complex, a heterodimer composed of TSLPR and IL-7 receptor α (CD127). TSLP activates multiple immune cell subsets expressing the TSLPR complex and plays a role in several models of disease. Although human monocytes express TSLPR and CD127 mRNAs in response to the TLR4 agonist LPS, their responsiveness to TSLP is poorly defined. We demonstrate that TSLP enhances human CD14+ monocyte CCL17 production in response to LPS and IL-4. Surprisingly, only a subset of CD14+ CD16- monocytes, TSLPR+ monocytes (TSLPR+ mono), expresses TSLPR complex upon LPS stimulation in an NF-κB- and p38-dependent manner. Phenotypic, functional, and transcriptomic analysis revealed specific features of TSLPR+ mono, including higher CCL17 and IL-10 production and increased expression of genes with important immune functions (i.e., GAS6, ALOX15B, FCGR2B, LAIR1). Strikingly, TSLPR+ mono express higher levels of the dendritic cell marker CD1c. This evidence led us to identify a subset of peripheral blood CD14+ CD1c+ cells that expresses the highest levels of TSLPR upon LPS stimulation. The translational relevance of these findings is highlighted by the higher expression of TSLPR and CD127 mRNAs in monocytes isolated from patients with Gram-negative sepsis compared with healthy control subjects. Our results emphasize a phenotypic and functional heterogeneity in an apparently homogeneous population of human CD14+ CD16- monocytes and prompt further ontogenetic and functional analysis of CD14+ CD1c+ and LPS-activated CD14+ CD1c+ TSLPR+ mono.

CD200 included in a 4-marker modified Matutes score provides optimal sensitivity and specificity for the diagnosis of chronic lymphocytic leukaemia.

CD200, a transmembrane type Ia glycoprotein belonging to the immunoglobulin superfamily, has been shown to have a differential expression in B-cell neoplasms. Here, we retrospectively assessed the diagnostic relevance of CD200 on 427 patients with B-cell chronic neoplasms in leukemic phase (median age, 69 y; range, 35-97 y). The final diagnosis based on the investigator's assessment was chronic lymphocytic leukaemia (CLL) in 75% of cases and non-CLL in 25% of cases. Sensitivity and specificity for the diagnosis of CLL (vs non-CLL) were calculated for the following markers: CD200, CD5, CD22, CD23, CD79b, FMC7, and SmIg. CD23 was the only marker without a statistically significant difference between the investigator assessment and the flowcytometric analysis. The other markers were unable-when individually evaluated-to discriminate between CLL and non-CLL, requiring the integration into a scoring system. The modified score no. 1 (addition of CD200) showed superimposable sensitivity and specificity compared with the Matutes score. The substitution of CD79b (modified score no. 2), surface membrane immunoglobulins (SmIg) (modified score no. 3), and CD79b and FMC7 (modified score no. 4) with CD200 showed that only the modified score no. 4 had both higher sensitivity and higher specificity compared with standard Matutes score. In conclusion, this work defines a simplified score, compared with the classical Matutes score, for the differential diagnosis of chronic B-cell leukaemia-which only requires 4 markers instead of 5 (CD5, CD23, CD200, and SmIg).

MicroRNAs as New Biomarkers for Diagnosis and Prognosis, and as Potential Therapeutic Targets in Acute Myeloid Leukemia.

Acute myeloid leukemias (AML) are clonal disorders of hematopoietic progenitor cells which are characterized by relevant heterogeneity in terms of phenotypic, genotypic, and clinical features. Among the genetic aberrations that control disease development there are microRNAs (miRNAs). miRNAs are small non-coding RNAs that regulate, at post-transcriptional level, translation and stability of mRNAs. It is now established that deregulated miRNA expression is a prominent feature in AML. Functional studies have shown that miRNAs play an important role in AML pathogenesis and miRNA expression signatures are associated with chemotherapy response and clinical outcome. In this review we summarized miRNA signature in AML with different cytogenetic, molecular and clinical characteristics. Moreover, we reviewed the miRNA regulatory network in AML pathogenesis and we discussed the potential use of cellular and circulating miRNAs as biomarkers for diagnosis and prognosis and as therapeutic targets.

Label-Free Quantitative Proteomics in a Methylmalonyl-CoA Mutase-Silenced Neuroblastoma Cell Line.

Methylmalonic acidemias (MMAs) are inborn errors of metabolism due to the deficient activity of methylmalonyl-CoA mutase (MUT). MUT catalyzes the formation of succinyl-CoA from methylmalonyl-CoA, produced from propionyl-CoA catabolism and derived from odd chain fatty acids ß-oxidation, cholesterol, and branched-chain amino acids degradation. Increased methylmalonyl-CoA levels allow for the presymptomatic diagnosis of the disease, even though no approved therapies exist. MMA patients show hyperammonemia, ketoacidosis, lethargy, respiratory distress, cognitive impairment, and hepatomegaly. The long-term consequences concern neurologic damage and terminal kidney failure, with little chance of survival. The cellular pathways affected by MUT deficiency were investigated using a quantitative proteomics approach on a cellular model of MUT knockdown. Currently, a consistent reduction of the MUT protein expression was obtained in the neuroblastoma cell line (SH-SY5Y) by using small-interfering RNA (siRNA) directed against an MUT transcript (MUT siRNA). The MUT absence did not affect the cell viability and apoptotic process in SH-SY5Y. In the present study, we evaluate and quantify the alterations in the protein expression profile as a consequence of MUT-silencing by a mass spectrometry-based label-free quantitative analysis, using two different quantitative strategies. Both quantitative methods allowed us to observe that the expression of the proteins involved in mitochondrial oxido-reductive homeostasis balance was affected by MUT deficiency. The alterated functional mitochondrial activity was observed in siRNA_MUT cells cultured with a propionate-supplemented medium. Finally, alterations in the levels of proteins involved in the metabolic pathways, like carbohydrate metabolism and lipid metabolism, were found.

Future in the Past: Azorella glabra Wedd. as a Source of New Natural Compounds with Antiproliferative and Cytotoxic Activity on Multiple Myeloma Cells.

Multiple myeloma (MM) is the second most common hematologic malignancy and, although the development of novel agents has improved survival of patients, to date, it remains incurable. Thus, newer and more effective therapeutic strategies against this malignancy are necessary. Plant extracts play an important role in anti-tumor drug discovery. For this reason, in the investigation of novel natural anti-MM agents, we evaluated the phytochemical profiles, in vitro antioxidant activity, and effects on MM cells of Azorella glabra (AG) Wedd. Total polyphenols (TPC), flavonoids (TFC), and terpenoids (TTeC) contents were different among samples and the richest fractions in polyphenols demonstrated a higher antioxidant activity in in vitro assays. Some fractions showed a dose and time dependent anti-proliferative activity on MM cells. The chloroform fraction (CHCl3) showed major effects in terms of reduction of cell viability, induction of apoptosis, and cell cycle arrest on MM cells. The apoptosis induction was also confirmed by the activation of caspase-3. Importantly, the CHCl3 fraction exhibited a negligible effect on the viability of healthy cells. These results encourage further investigations on AG extracts to identify specific bioactive compounds and to define their potential applications in MM.

[Network references for rare diseases: state of the art for the paroxysmal nocturnal hemoglobinuria]. / I network di riferimento per le malattie rare: lo stato dell'arte per l'emoglobinuria parossistica notturna.

BACKGROUND: recently, healthcare network models have been proposed to improve general awareness of rare diseases for patients and specific knowledge about diagnosis, treatment, and management for healthcare services. Paroxysmal nocturnal hemoglobinuria (PNH) is a rare haematological disease that still has no framing in an official network. OBJECTIVES: to describe the use of network models in diagnosis, treatment, and management of PNH patients both in Italy and abroad and its impact on patients and healthcare service. DISEGN: literature search was performed using the keywords "Hemoglobinuria", "Network", "PHN", and "Screening" in both MedLine and EMBASE. Search was restricted to the articles published in the last 5 years and written in English, French or Italian language. RESULTS: from the total 251 articles of the initial search, only 21 were finally included in our review. None of the included study explicitly described a network model. In general, we were able to identify two different kind of networks implicitly described in the studies: laboratory networks for diagnostic harmonization or screening of the population at risk of PNH (10/21 studies) and PNH registry as network of clinical information to be use for better understanding of the natural history of the disease and to assess therapeutic effectiveness (11/21 studies). CONCLUSIONS: few network approaches in PNH diagnosis, treatment, and management are described in literature. Despite the scarce application of the networks, our review highlights the positive impact that networks have in both patients and healthcare services.

DiGeorge-like syndrome in a child with a 3p12.3 deletion involving MIR4273 gene born to a mother with gestational diabetes mellitus.

Chromosome 22q11.2 deletion is the most common chromosomal alteration associated with DiGeorge syndrome (DGS), even though this is not the only underlying cause of DGS. In rare patients, mutations in a single gene, TBX1, have been described resulting in a DGS phenotype. Recently, it has been reported that at least part of the TBX1 mutant phenotype is due to excessive bone morphogenetic proteins (BMP) signaling. Evidence suggests that miRNA may modulate the expression of critical T-box transcriptional regulators during midface development and Bmp-signaling. We report on a 7-year-old Caucasian male born to a mother affected with gestational diabetes (GDM) who had a 371Kb-interstitial deletion of 3p12.3 identified by array CGH, involving the ZNF717, MIR1243, and 4273 genes. The child presented with a DiGeorge anomaly (DGA) associated with unilateral renal agenesis and language delay. The immunological evaluation revealed a severe reduction and impairment of T lymphocytes. FISH analysis and TBX1 sequencing were negative. Among the miRNA-4273 predicted target genes, we found BMP3, which is involved in several steps of embryogenesis including kidney and lung organogenesis and in insulin gene expression. Since, DGA is not commonly found in newborns of diabetic mothers, we hypothesize that the pathogenesis of DGA associated with GDM is multifactorial, involving both genetic and/or epigenetic cofactors.

Multicenter validation of a simplified method for paroxysmal nocturnal hemoglobinuria screening.

BACKGROUND: Paroxysmal nocturnal hemoglobinuria (PNH) diagnostic guidelines recommend single-tube five- to six-color or two-tube four-color assays. PNH clones are detectable in only a fraction of patients at risk, and screening for new PNH cases can be complex and expensive. In this multicenter study, we have validated a simplified, one-tube two-color FLAER-based assay suitable for PNH screening. METHODS: Six laboratories received samples containing spiked PNH leukocyte clones to be analyzed in parallel with a common six-color cocktail (FLAER/CD24/CD45/CD64/CD15/CD14) and a simplified two-color mixture (FLAER/CD15), a shared calibration procedure, and a common analysis protocol. Replicate precision and sensitivity tests were performed on PNH patients, from undiluted to 1:10 000. Specificity tests were performed on normal donors to identify the possible sources of artifacts. RESULTS: The performance comparison between six-color and two-color assays showed an excellent agreement for granulocyte PNH clones. Dilution experiments showed an accurate detectability down to 0.01% sensitivity level for granulocyte PNH clones and to 1% for monocytes. Specificity experiments disclosed that basophils and platelets can contaminate the monocyte gate and generate false PNH events. CONCLUSIONS: A simplified two-color (FLAER/CD15) PNH screening test has been validated in a highly standardized multicenter study and proved feasible and effective in ongoing regional programs. Precision, sensitivity, and specificity of the simplified test for granulocytes were comparable to the more complex and expensive six-color assay and applicable for screening also in peripheral laboratories. The diagnostic confirmation of PNH should be always performed by a reference center using the established technique on all cell lineages.

Mesenchymal Stem Cell Derived Extracellular Vesicles: A Role in Hematopoietic Transplantation?

Mesenchymal stem cells (MSCs) are a heterogeneous cellular population containing different progenitors able to repair tissues, support hematopoiesis, and modulate immune and inflammatory responses. Several clinical trials have used MSCs in allogeneic hematopoietic stem cell transplantation (allo-HSCT) to prevent hematopoietic stem cell (HSC) engraftment failure, reduce aplasia post chemotherapy, and to control graft versus host disease (GvHD). The efficacy of MSCs is linked to their immune suppressive and anti-inflammatory properties primarily due to the release of soluble factors. Recent studies indicate that most of these effects are mediated by extracellular vesicles (EVs). MSC-EVs have therefore therapeutic effects in regenerative medicine, tumor inhibition, and immune-regulation. MSC-EVs may offer specific advantages for patient safety, such as lower propensity to trigger innate and adaptive immune responses. It has been also shown that MSC-EVs can prevent or treat acute-GvHD by modulating the immune-response and, combined with HSCs, may contribute to the hematopoietic microenvironment reconstitution. Finally, MSC-EVs may provide a new potential therapeutic option (e.g., transplantation, gene therapy) for different diseases, particularly hematological malignancies. In this review, we will describe MSC and MSC-EVs role in improving allo-HSCT procedures and in treating GvHD.

Extracellular Vesicles in Hematological Malignancies: From Biology to Therapy.

Extracellular vesicles (EVs) are a heterogeneous group of particles, between 15 nanometers and 10 microns in diameter, released by almost all cell types in physiological and pathological conditions, including tumors. EVs have recently emerged as particularly interesting informative vehicles, so that they could be considered a true "cell biopsy". Indeed, EV cargo, including proteins, lipids, and nucleic acids, generally reflects the nature and status of the origin cells. In some cases, EVs are enriched of peculiar molecular cargo, thus suggesting at least a degree of specific cellular packaging. EVs are identified as important and critical players in intercellular communications in short and long distance interplays. Here, we examine the physiological role of EVs and their activity in cross-talk between bone marrow microenvironment and neoplastic cells in hematological malignancies (HMs). In these diseases, HM EVs can modify tumor and bone marrow microenvironment, making the latter "stronger" in supporting malignancy, inducing drug resistance, and suppressing the immune system. Moreover, EVs are abundant in biologic fluids and protect their molecular cargo against degradation. For these and other "natural" characteristics, EVs could be potential biomarkers in a context of HM liquid biopsy and therapeutic tools. These aspects will be also analyzed in this review.

Peptide inhibitors of C3 activation as a novel strategy of complement inhibition for the treatment of paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by complement-mediated intravascular hemolysis due to the lack of CD55 and CD59 on affected erythrocytes. The anti-C5 antibody eculizumab has proven clinically effective, but uncontrolled C3 activation due to CD55 absence may result in opsonization of erythrocytes, possibly leading to clinically meaningful extravascular hemolysis. We investigated the effect of the peptidic C3 inhibitor, compstatin Cp40, and its long-acting form (polyethylene glycol [PEG]-Cp40) on hemolysis and opsonization of PNH erythrocytes in an established in vitro system. Both compounds demonstrated dose-dependent inhibition of hemolysis with IC50 ∼4 µM and full inhibition at 6 µM. Protective levels of either Cp40 or PEG-Cp40 also efficiently prevented deposition of C3 fragments on PNH erythrocytes. We further explored the potential of both inhibitors for systemic administration and performed pharmacokinetic evaluation in nonhuman primates. A single intravenous injection of PEG-Cp40 resulted in a prolonged elimination half-life of >5 days but may potentially affect the plasma levels of C3. Despite faster elimination kinetics, saturating inhibitor concentration could be reached with unmodified Cp40 through repetitive subcutaneous administration. In conclusion, peptide inhibitors of C3 activation effectively prevent hemolysis and C3 opsonization of PNH erythrocytes, and are excellent, and potentially cost-effective, candidates for further clinical investigation.

Inverse regulation of bridging integrator 1 and BCR-ABL1 in chronic myeloid leukemia.

Endocytosis is the major regulator process of tyrosine kinase receptor (RTK) functional activities. Bridging integrator 1 (BIN1) is a key protein involved in RTK intracellular trafficking. Here, we report, by studying 34 patients with chronic myeloid leukemia (CML) at diagnosis, that BIN1 gene is downregulated in CML as compared to healthy controls, suggesting an altered endocytosis of RTKs. Rab interactor 1 (RIN1), an activator of BIN1, displayed a similar behavior. Treatment of 57 patients by tyrosine kinase inhibitors caused, along with BCR-ABL1 inactivation, an increase of BIN1 and RIN1 expression, potentially restoring endocytosis. There was a significant inverse correlation between BIN1-RIN1 and BCR-ABL1 expression. In vitro experiments on both CML and nontumorigenic cell lines treated with Imatinib confirmed these results. In order to provide another proof in favor of BIN1 and RIN1 endocytosis function in CML, we demonstrated that Imatinib induced, in K562 cell line, BIN1-RIN1 upregulation accompanied by a parallel AXL receptor internalization into cytoplasmic compartment. This study shows a novel deregulated mechanism in CML patients, indicating BIN1 and RIN1 as players in the maintenance of the abnormal RTK signaling in this hematological disease.

Inhibition of PID1/NYGGF4/PCLI1 gene expression highlights its role in the early events of the cell cycle in NIH3T3 fibroblasts.

The PID1/NYGGF4/PCLI1 gene encodes for a protein with a phosphotyrosine-binding domain, which interacts with the lipoprotein receptor-related protein 1. Previous work by us and others suggested a function of the gene in cell proliferation of NIH3T3 fibroblasts and 3T3-L1 pre-adipocytes. The molecular characterization of PCLI1 protein, ectopically expressed in NIH3T3 fibroblasts, revealed two phosphorylation sites at Ser154 and Ser165. In order to clarify the functions of this gene, we analyzed the effects of its downregulation on cellular proliferation and cell cycle progression in NIH3T3 cell cultures. Downregulation of PID1/NYGGF4/PCLI1 mRNA levels by short hairpin RNAs (shRNAs) elicited decreased proliferation rate in mammalian cell lines; cell cycle analysis of serum-starved, synchronized NIH3T3 fibroblasts showed an increased accumulation of shRNA-interfered cells in the G1 phase. Decreased levels of FOS and MYC mRNAs were accordingly associated with these events. The molecular scenario emerging from our data suggests that PID1/NYGGF4/PCLI1 controls cellular proliferation and cell cycle progression in NIH3T3 cells.

High serum levels of extracellular vesicles expressing malignancy-related markers are released in patients with various types of hematological neoplastic disorders.

Many cell types release extracellular vesicles (EVs), including exosomes, microvesicles (MVs), and apoptotic bodies, which play a role in physiology and diseases. Presence and phenotype of circulating EVs in hematological malignancies (HMs) remain largely unexplored.The aim of this study was to characterize EVs in peripheral blood of HM patients compared to healthy subjects (controls). We isolated serum EVs from patients with chronic lymphocytic leukemia (CLL), non-Hodgkin's lymphoma (NHL), Waldenstrom's macroglobulinemia (WM), Hodgkin's lymphoma (HL), multiple myeloma (MM), acute myeloid leukemia (AML), myeloproliferative neoplasms (MPNs), myelodysplastic syndromes (MDS), and controls. EVs were isolated from serum of peripheral blood by ultracentrifuge steps and analyzed by flow cytometry to define count, size, and immunophenotype. MV levels were significantly elevated in WM, HL, MM, AML, and some MPNs and, though at a lesser degree, in CLL and NHL as compared to healthy controls. HL, MM, and MPNs generated a population of MVs characterized by lower size (below 0.3 µm) when compared to controls. MVs from patients specifically expressed tumor-related antigens, such as CD19 in B cell neoplasms, CD38 in MM, CD13 in myeloid tumors, and CD30 in HL. Both total and antigen-specific count of MVs significantly correlated with different HM clinical features such as Rai stage in CLL, International Prognostic Scoring System in WM, International Staging System in MM, and clinical stage in HL. MVs may represent a novel biomarker in HMs.

Hematopoietic stem/progenitor cells express myoglobin and neuroglobin: adaptation to hypoxia or prevention from oxidative stress?

Oxidative metabolism and redox signaling prove to play a decisional role in controlling adult hematopoietic stem/progenitor cells (HSPCs) biology. However, HSPCs reside in a hypoxic bone marrow microenvironment raising the question of how oxygen metabolism might be ensued. In this study, we provide for the first time novel functional and molecular evidences that human HSPCs express myoglobin (Mb) at level comparable with that of a muscle-derived cell line. Optical spectroscopy and oxymetry enabled to estimate an O2-sensitive heme-containing protein content of approximately 180 ng globin per 10(6) HSPC and a P50 of approximately 3 µM O2. Noticeably, expression of Mb mainly occurs through a HIF-1-induced alternative transcript (Mb-V/Mb-N = 35 ± 15, p < .01). A search for other Mb-related globins unveiled significant expression of neuroglobin (Ngb) but not of cytoglobin. Confocal microscopy immune detection of Mb in HSPCs strikingly revealed nuclear localization in cell subsets expressing high level of CD34 (nuclear/cytoplasmic Mb ratios 1.40 ± 0.02 vs. 0.85 ± 0.05, p < .01) whereas Ngb was homogeneously distributed in all the HSPC population. Dual-color fluorescence flow cytometry indicated that while the Mb content was homogeneously distributed in all the HSPC subsets that of Ngb was twofold higher in more immature HSPC. Moreover, we show that HSPCs exhibit a hypoxic nitrite reductase activity releasing NO consistent with described noncanonical functions of globins. Our finding extends the notion that Mb and Ngb can be expressed in nonmuscle and non-neural contexts, respectively, and is suggestive of a differential role of Mb in HSPC in controlling oxidative metabolism at different stages of commitment.

ABCG2, a novel antigen to sort luminal progenitors of BRCA1- breast cancer cells.

INTRODUCTION: Tumor-initiating cells (TICs), aka "cancer stem cells", are believed to fuel tumors and to sustain therapy resistance and systemic metastasis. Breast cancer is the first human carcinoma in which a subpopulation of cells displaying a specific CD44+/CD24-/low/ESA+ antigenic phenotype was found to have TIC properties. However, CD44+/CD24-/low/ESA+ is not a universal marker phenotype of TICs in all breast cancer subtypes. The aim of this study was to identify novel antigens with which to isolate the TIC population of the basal-A/basal-like breast cancer cell lines. METHODS: We used polychromatic flow-cytometry to characterize the cell surface of several breast cancer cell lines that may represent different tumor molecular subtypes. We next used fluorescence-activated cell sorting to isolate the cell subpopulations of interest from the cell lines. Finally, we explored the stem-like and tumorigenic properties of the sorted cell subpopulations using complementary in vitro and in vivo approaches: mammosphere formation assays, soft-agar colony assays, and tumorigenic assays in NOD/SCID mice. RESULTS: The CD44+/CD24+ subpopulation of the BRCA1-mutated basal-A/basal-like cell line HCC1937 is enriched in several stemness markers, including the ABCG2 transporter (i.e., the CD338 antigen). Consistently, CD338-expressing cells were also enriched in CD24 expression, suggesting that coexpression of these two antigenic markers may segregate TICs in this cell line. In support of ABCG2 expression in TICs, culturing of HCC1937 cells in ultra-low adherent conditions to enrich them in precursor/stem-cells resulted in an increase in CD338-expressing cells. Furthermore, CD338-expressing cells, unlike their CD338-negative counterparts, displayed stemness and transformation potential, as assessed in mammosphere and colony formation assays. Lastly, CD338-expressing cells cultured in ultra-low adherent conditions maintained the expression of CD326/EpCAM and CD49f/α6-integrin, which is a combination of antigens previously assigned to luminal progenitors. CONCLUSION: Collectively, our data suggest that CD338 expression is specific to the tumor-initiating luminal progenitor subpopulation of BRCA1-mutated cells and is a novel antigen with which to sort this subpopulation.

The complement receptor 2/factor H fusion protein TT30 protects paroxysmal nocturnal hemoglobinuria erythrocytes from complement-mediated hemolysis and C3 fragment.

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by complement-mediated intravascular hemolysis because of the lack from erythrocyte surface of the complement regulators CD55 and CD59, with subsequent uncontrolled continuous spontaneous activation of the complement alternative pathway (CAP), and at times of the complement classic pathway. Here we investigate in an in vitro model the effect on PNH erythrocytes of a novel therapeutic strategy for membrane-targeted delivery of a CAP inhibitor. TT30 is a 65 kDa recombinant human fusion protein consisting of the iC3b/C3d-binding region of complement receptor 2 (CR2) and the inhibitory domain of the CAP regulator factor H (fH). TT30 completely inhibits in a dose-dependent manner hemolysis of PNH erythrocytes in a modified extended acidified serum assay, and also prevents C3 fragment deposition on surviving PNH erythrocytes. The efficacy of TT30 derives from its direct binding to PNH erythrocytes; if binding to the erythrocytes is disrupted, only partial inhibition of hemolysis is mediated by TT30 in solution, which is similar to that produced by the fH moiety of TT30 alone, or by intact human fH. TT30 is a membrane-targeted selective CAP inhibitor that may prevent both intravascular and C3-mediated extravascular hemolysis of PNH erythrocytes and warrants consideration for the treatment of PNH patients.

Human skin-derived keratinocytes and fibroblasts co-cultured on 3D poly ε-caprolactone scaffold support in vitro HSC differentiation into T-lineage committed cells.

In humans, the thymus is the primary lymphoid organ able to support the development of T cells through its three-dimensional (3D) organization of the thymic stromal cells. Since a remarkable number of similarities are shared between the thymic epithelial cells (TECs) and skin-derived keratinocytes and fibroblasts, in this study we used human keratinocytes seeded with fibroblasts on the 3D poly ε-caprolactone scaffold to evaluate their ability to replace TECs in supporting T-cell differentiation from human haematopoietic stem cells (HSCs). We observed that in the multicellular biocomposite, early thymocytes expressing CD7(+)CD1a(+), peculiar markers of an initial T-cell commitment, were de novo generated. Molecular studies of genes selectively expressed during T-cell development revealed that TAL1 was down-regulated and Spi-B was up-regulated in the cell suspension, consistently with a T-cell lineage commitment. Moreover, PTCRA and RAG2 expression was detected, indicative of a recombinant activity, required for the generation of a T-cell receptor repertoire. Our results indicate that in the multicellular biocomposite, containing skin-derived elements in the absence of thymic stroma, HSCs do start differentiating toward a T-cell lineage commitment. In conclusion, the construct described in this study exerts some properties of a lymphoid organoid, suitable for future clinical applications in cell-based therapies.