The Role of the IAP Livin in Megakaryocytes Differentiation and Thrombopoiesis

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3297-3297
Author(s):  
Ihab Abd-Elrahman ◽  
Varda R Deutsch ◽  
Marjorie Pick ◽  
Sigi Kay ◽  
Tzahi Neuman ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Potential Role ◽  
Conflicts Of Interest ◽  
Cell Activity ◽  
Human Cell Line ◽  
Over Expression ◽  
Immunohistochemistry Staining ◽  
Apoptotic Activity ◽  
Apoptosis Proteins

Abstract Abstract 3297 In this study we observe that Livin plays a role in thrombopoiesis. Livin is a member of the Inhibitor of Apoptosis Proteins (IAP) family of intracellular anti-apoptotic proteins that acts by binding and inhibiting caspases. Previously we found that Livin is unique among the IAP members as upon strong apoptotic stimuli, it is specifically cleaved by caspases to produce a truncated protein (tLivin) that has a paradoxical pro-apoptotic activity. Here we have shown that Livin is expressed in normal mature bone marrow MK and in platelets. Objective: The objective of this study was to evaluate the potential role of Livin in thrombopoiesis. Methods: We studied Livin expression in normal BM using immunohistochemistry staining. We studied the ability of primary MK generated from CD34+progenitor cells over-expressing Livin to produce platelets. While, the human cell line, LAMA-84, was induced by a phorbol myristic acid (PMA) to differentiate to megakaryocytes (MK) to evaluate the potential role of Livin in thrombopoiesis. Results and conclusions: Livin over-expression in CD34+ progenitor cells induced differentiation of these cells into MK and increased the ability of these primary MK to produce platelets. LAMA-84, upon differentiation into MK, produces platelets that are functional and capable of aggregating. This thrombopoiesis was accompanied by increased Livin expression and downregulation of other IAPs: XIAP and Survivin. Our results show that Livin plays a dual role in thrombopoiesis, demonstrating both an anti and pro-apoptotic role in cell activity. Disclosures: No relevant conflicts of interest to declare.

scholarly journals SAT0014 ENDOTHELIAL PROGENITOR CELLS: ROLE IN ENDOTHELIAL DAMAGE OF INTERSTITIAL LUNG DISEASE ASSOCIATED TO RHEUMATOID ARTHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 937.1-937
Author(s):  
V. Pulito-Cueto ◽  
S. Remuzgo-Martínez ◽  
F. Genre ◽  
V. M. Mora-Cuesta ◽  
D. Iturbe Fernández ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Interstitial Lung Disease ◽  
Lung Disease ◽  
Progenitor Cells ◽  
Endothelial Progenitor Cells ◽  
Potential Role ◽  
Endothelial Damage ◽  
Research Support ◽  
Endothelial Progenitor

Background:Interstitial lung disease (ILD) is one of the most significant comorbidities of rheumatoid arthritis (RA), increasing the mortality in these patients [1,2]. Although the pathogenesis of ILD associated to RA (RA-ILD+) remains poorly defined [1], it is known that vascular tissue plays a crucial role in lung physiology [3]. In this context, a population of cells termed endothelial progenitor cells (EPC) are involved in vasculogenesis and endothelial tissue repair [4]. Previous reports suggest the implication of EPC in different conditions such as RA and idiopathic pulmonary fibrosis (IPF), the most common and destructive ILD [5,6]. Nevertheless, little is known about their specific role in RA-ILD+.Objectives:The purpose of this study was to shed light on the potential role of EPC in endothelial damage in RA-ILD+.Methods:Peripheral venous blood was collected from a total of 68 individuals (18 with RA-ILD+, 17 with RA-ILD-, 19 with IPF and 14 healthy controls). All subjects were recruited from the Rheumatology and Pneumology departments of Hospital Universitario Marqués de Valdecilla, Santander, Spain. Quantification of EPC was analyzed by the expression of surface antigens by flow cytometry. The combination of antibodies against the stem cell marker CD34, the immature progenitor marker CD133, the endothelial marker VEGF receptor 2 (CD309) and the common leukocyte antigen CD45 was used. EPC were considered as CD34+, CD45Low, CD309+and CD133+. All statistical analyses were performed using Prism software 5 (GraphPad).Results:EPC frequency was significantly increased in patients with RA-ILD+, RA-ILD-and IPF compared to controls (p=0.001, p=0.002, p< 0.0001, respectively). Nevertheless, patients with RA, both RA-ILD+and RA-ILD-, showed a lower frequency of EPC than those with IPF (p= 0.048, p= 0.006, respectively).Conclusion:Our results provide evidence for a potential role of EPC as a reparative compensatory mechanism related to endothelial damage in RA-ILD+, RA-ILD-and IPF patients. Interestingly, EPC frequency may help to establish a differential diagnostic between patients with IPF and those who have an underlying autoimmune disease (RA-ILD+).References:[1] J Clin Med 2019; 8: 2038;[2] Arthritis Rheumatol 2015; 67: 28-38;[3] Nat Protoc 2015; 10: 1697-1708;[4] Science 1997; 275: 964-966;[5] Rheumatology (Oxford) 2012; 51: 1775-1784;[6] Angiogenesis 2013; 16: 147-157.Acknowledgments:Personal funds, VP-C: PREVAL18/01 (IDIVAL); SR-M: RD16/0012/0009 (ISCIII-ERDF); LL-G: PI18/00042 (ISCIII-ERDF); RL-M: Miguel Servet type I CP16/00033 (ISCIII-ESF).Disclosure of Interests:Verónica Pulito-Cueto: None declared, Sara Remuzgo-Martínez: None declared, Fernanda Genre: None declared, Victor Manuel Mora-Cuesta: None declared, David Iturbe Fernández: None declared, Sonia Fernández-Rozas: None declared, Leticia Lera-Gómez: None declared, Pilar Alonso Lecue: None declared, Javier Rodriguez Carrio: None declared, Belén Atienza-Mateo: None declared, Virginia Portilla: None declared, David Merino: None declared, Ricardo Blanco Grant/research support from: AbbVie, MSD, Roche, Consultant of: Abbvie, Eli Lilly, Pfizer, Roche, Bristol-Myers, Janssen, UCB Pharma and MSD, Speakers bureau: Abbvie, Eli Lilly, Pfizer, Roche, Bristol-Myers, Janssen, UCB Pharma. MSD, Alfonso Corrales Speakers bureau: Abbvie, Jose Manuel Cifrián-Martínez: None declared, Raquel López-Mejías: None declared, Miguel A González-Gay Grant/research support from: Pfizer, Abbvie, MSD, Speakers bureau: Pfizer, Abbvie, MSD

Potential role of endothelial progenitor cells in the pathophysiology of heart failure: Clinical implications and perspectives

2006 ◽  
Vol 189 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Ioannis Andreou ◽  
Dimitris Tousoulis ◽  
Costas Tentolouris ◽  
Charalambos Antoniades ◽  
Christodoulos Stefanadis
Keyword(s):  
Heart Failure ◽  
Progenitor Cells ◽  
Endothelial Progenitor Cells ◽  
Potential Role ◽  
Clinical Implications ◽  
Endothelial Progenitor

Mobilization Studies in Complement-Deficient Mice Reveal That AMD3100 Mobilization Depends On Complement Cascade Activation and Suggest Involvement of “Membrane Attack Complex - MAC” in Egress of Hematopoietic Stem/Progenitor Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 367-367
Author(s):  
Marcin Wysoczynski ◽  
HakMo Lee ◽  
Rui Liu ◽  
Wan Wu ◽  
Janina Ratajczak, ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Conflicts Of Interest ◽  
Membrane Attack Complex ◽  
Classical Pathway ◽  
Compensatory Mechanism ◽  
Complement Cascade ◽  
Cxcr4 Antagonist ◽  
Hematopoietic Stem ◽  
Deficient Mice

Abstract Abstract 367 We reported that complement cascade (CC) becomes activated in bone marrow (BM) during mobilization of hematopoietic stem/progenitor cells (HSPCs) by immunoglobulin (Ig)-dependent pathway and/or by alternative Ig-independent pathway as seen during G-CSF- or Zymosan mobilization, respectively. As a result, several potent bioactive CC anaphylatoxins (C3 and C5 cleavage fragments) are released that regulate egress of HSPCs (Blood 2003;101,3784; Blood 2004;103,2071; Blood 2005;105,40, Leukemia 2009; in press.). This explains why: i) NOD/SCID and RAG-/- animals that do not activate the Ig-dependent CC classical pathway; ii) C2fB-/- and C3-/- mice that do not activate the classical and alternative CC pathways; and iii) C5-/- mice that do not activate the distal pathway of CC are all poor G-CSF- and/or Zymosan mobilizers. In this study, we evaluated the role of CC in mobilization induced by CXCR4 antagonist AMD3100. We noticed that all CC activation-deficient mice mentioned above, except C5-/- mice, mobilize normally in response to AMD3100 administration. Accordingly, the number of mobilized CD34- SKL cells, leucocytes, and CFU-GM clonogeneic progenitors in mutant mice was similar to wt littermates. More important we observed that AMD3100 mobilization of HSPCs was preceded by a massive egress of leucocytes from BM and that AMD3100 was able to stimulate in these cells i) phosphorylation of MAPKp42/44 and ii) secretion of MMP-9. At the same time, ELISA data to detect CC activation revealed that serum levels of CC cleavage fragments, which were low in the initial phase of AMD3100 mobilization during granulocyte egress, become elevated later during HSPC egress. Thus, our data show that despite a fact that G-CSF and AMD3100 mobilize HSPCs by involving different mechanisms, activation of CC is a common phenomenon occurring during mobilization induced by both compounds. This further supports a pivotal role of CC activation in the egress of HSPCs from BM; however, both compounds activate CC differently. While G-CSF administration initiates CC activation at its proximal C1q-C3 level, AMD3100 induces CC activation at the distal C5 level, pointing to a crucial role of C5 cleavage in executing mobilization. To support this, all mice employed in our studies that display defects in activation of proximal stages of CC (NOD/SCID, RAG, C2fB-/-, and C3-/-) are normal AMD3100 mobilizers. However, C5 is cleavage required for mobilization occurs in the plasma of these animals latter on - directly by proteases released from AMD3100-stimulated granulocytes that egress from the BM as a first wave of mobilized cells. This compensatory mechanism cannot occur from obvious reasons in C5-/- mice. We conclude that AMD3100-directed mobilization similarly as G-CSF-induced one depends on activation of CC; however, AMD3100 in contrast to G-CSF activates CC at distal stages – directly by proteases released from mobilized/activated granulocytes. Cleavage of C5 and release of C5a and desArgC5a create a sinusoid-permissive environment in BM for HSPCs egress. This suggests involvement of both C5 cleavage fragments as well as a potential role of downstream elements of CC activation - membrane attack complex - MAC (C5b-C9) in stem cell mobilization. Therefore, some poor AMD3100 patient responders could possess a defect in activation of the distal steps of CC. Disclosures: No relevant conflicts of interest to declare.

A HoxD11 Homeobox Gene Mutation Associated With Congenital Absent Radius But Without The Thrombocytopenia Of The TAR Syndrome Or a HoxA11 Mutation

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4837-4837
Author(s):  
Roger A. Fleischman
Keyword(s):  
Potential Role ◽  
Conflicts Of Interest ◽  
Homeobox Genes ◽  
Homeobox Gene ◽  
Incomplete Penetrance ◽  
Potential Candidate ◽  
Negative Finding ◽  
Tar Syndrome ◽  
Absent Radius

HoxA11 and HoxD11 are homeobox genes critical for normal development of the forearm and thus are potential candidate genes for involvement in the pathogenesis of the thrombocytopenia/absent radius (TAR) syndrome. However, we previously reported an absence of coding sequence mutations in either HoxA11 or HoxD11 in a series of 10 unrelated TAR syndrome patients (Fleischman RA et al., Br J Haematol., 116:367-75, 2002). Despite this negative finding, interest in the potential role of homeobox genes in the TAR syndrome has been supported by a report of a HoxA11 mutation occurring in two kindreds with amegakaryocytic thrombocytopenia and radio-ulnar synostosis, a less pronounced more proximal pattern of radial malformation (Thompson AA and Nguyen LT. Nat Genet., 26:397-8, 2000). Unlike HoxA11, however, no mutations in the human HoxD11 gene have been described thus far that would help elucidate the potential role of this paralogous gene in megakaryopoiesis or the TAR syndrome. We now describe a novel mutation in human HoxD11 that results in a polyalanine sequence expansion, (GCG)6→ (GCG)8, and report that this mutation is associated with a unilateral absent radius in the affected propositus. A familial syndrome is suggested in this kindred, moreover, by the prior observation of a bilateral absent radius in a deceased maternal aunt. This mutation was not present in more than 100 unrelated normal subjects or 8 other unrelated individuals with sporadic absence of the radius. Two other living maternal relatives also carried the mutation but did not exhibit any radial defects, a finding consistent with autosomal dominance with incomplete penetrance, an inheritance pattern reported for short polyalanine expansion mutations in the related homeobox gene HoxD13 which cause synpolydactyly. In contrast to the reported HoxA11 mutation, however, neither the propositus nor the mutation carriers of this HoxD11 mutation exhibited thrombocytopenia or any other cytopenias or congenital defect. The results suggest that at least one class of mutation in human HoxD11 may be sufficient to cause an absent radius syndrome but unlike the reported HoxA11 mutation, does not adversely affect megakaryopoiesis. The findings further suggest that additional studies of the TAR syndrome may be necessary to exclude as yet undetected non-coding mutations in promoter or enhancer sequences that alter the expression of HoxA11, HoxD11 or other homeobox genes critical for radial development and/or megakaryopoiesis. This work was supported by a VA Merit Award. Disclosures: No relevant conflicts of interest to declare.

Inhibition of Alloreactive Cytotoxic T Cell Activity by HIV-Positive Sera: Potential Role of Circulating Soluble HLA Class I Molecules

1994 ◽  
Vol 10 (9) ◽  
pp. 1061-1064 ◽  
Author(s):  
FRANCESCO PUPPO ◽  
SABRINA BRENCI ◽  
ELEONORA MONTINARO ◽  
LORELLA LANZA ◽  
PAOLA CONTINI ◽  
...  
Keyword(s):  
T Cell ◽  
Potential Role ◽  
Cell Activity ◽  
Hla Class I ◽  
Class I ◽  
Cytotoxic T Cell ◽  
Hiv Positive ◽  
Hla Class I Molecules ◽  
Soluble Hla

RNAi-Mediated Inhibition of Mcl-1 Expression Enhances Apoptosis in Imatinib-Treated CML Progenitors

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1669-1669
Author(s):  
Su Chu ◽  
Ravi Bhatia
Keyword(s):  
Flow Cytometry ◽  
Progenitor Cells ◽  
Colony Formation ◽  
Cell Expansion ◽  
Kinase Inhibitor ◽  
Conflicts Of Interest ◽  
Family Members ◽  
Control Shrna ◽  
Cd34 Cells

Abstract Abstract 1669 Tyrosine kinase inhibitor (TKI) treatment inhibits proliferation in CML stem/progenitor cells, but only modestly increases apoptosis. Residual leukemia stem cells remain a potential source of disease relapse in IM-treated patients. The Bcl-2 family of anti-apoptotic proteins plays a central role in the regulation of apoptosis. Several Bcl-2 inhibitors are being evaluated in preclinical and clinical studies and there is considerable interest in evaluating their ability to induce apoptosis in CML stem and progenitor cells. However these agents have considerable toxicity possibly related to lack of selectivity for individual family members. We performed a functional siRNA screen to determine the role of individual Bcl-2 family members in maintaining survival of in CML and normal CD34+ cells. CML and normal CD34+ cells were transfected with siRNAs targeting Bcl-2, Bcl-2L1, Bcl-2L2, Bcl-2L10, Mcl-1 and Bcl2A1. In this screen Mcl-1 knockdown resulted in significant reduction in viability of CML CD34+ cells, with or without co-treatment with IM (1uM). Significant reduction in normal CD34+ viability was not seen. These results were validated using different siRNA sequences to knockdown Mcl1 expression. Increased apoptosis of CML but not normal CD34+ cells was seen (23±8% for CML vs. 4.2±1.5% for normal CD34+ cells, n=3, p<0.5). CML CD34+ cell apoptosis was further enhanced by combination of Mcl-1 inhibition with IM treatment (48±15% for CML vs. 7.2±3% for CB progenitors, p<0.1). To further evaluate the role of Mcl-1 in regulating CML CD34+ cell growth, an anti-Mcl-1 shRNA construct was cloned into the pHIV7-SF-RFP lentivirus vector. Cord blood and CML CD34+ cells were transduced with Mcl-1 specific or control, non-specific shRNA expressing vectors. Western blotting demonstrated effective knockdown of Mcl-1 protein levels in Mcl-1 shRNA transduced CD34+cells (82% reduction in CML and 78% in normal CD34+ cells). CD34+ RFP+ cells were selected by flow cytometry and cultured in presence and absence of IM. A significant increase in apoptosis was seen in Mcl-1 knockdown CML CD34+ cells compared with control shRNA-transduced cells, and further increase in apoptosis was seen following IM treatment (4.7±0.5 for control shRNA-transduced cells VS 25.7±2.1 for Mcl-1 knockdown cells). Mcl-1 knockdown CML CD34+ cells generated fewer colonies in methylcellulose progenitor culture (93 colonies for control siRNA transduced cells vs. 31 colonies for Mcl-1 knockdown cells) and demonstrated reduced cell expansion following culture with growth factor (SCF; IL3; GM-CSF and G-CSF) compared with control shRNA transduced cells (383,750± 172,476 for control shRNA-transduced cells 224,250± 87,044 for Mcl-1 knockdown cells). Cell expansion was further reduced with IM treatment. Mcl-1 knockdown resulted in complete loss of erythroid colony formation. Analysis of cell differentiation by flow cytometry after culture for 4 or 7 days revealed that Mcl-1 knockdown resulted in reduced generation of both erythroid (GPA+) and myeloid (CD33+ and CD14+) cells. In contrast to the results of the initial siRNA studies, shRNA-mediated Mcl-1 knockdown also resulted in significantly increased apoptosis of normal CD34+ cells (12.6± 1.6% for control shRNA-transduced cells and 24.5± 0.9% for Mcl-1 knockdown cells) associated with reduced colony formation and reduced growth in culture (1.265e+006± 273,892 for control shRNA-transduced cells 589,000 ± 188,082 for Mcl-1 knockdown cells). We conclude that RNAi-mediated Mcl-1 knockdown inhibits CML CD34+ cell survival and proliferation and enhances apoptosis after IM treatment, but also reduces viability of normal CD34+ cells. Since Mcl-1 protein expression is subject to multiple levels of regulation, our results suggest that strategies to selectively target Mcl-1 regulatory mechanisms active in CML but not normal progenitors may be less toxic and have greater clinical utility than direct targeting of the protein. Disclosures: No relevant conflicts of interest to declare.

Over-expression and potential role of cyclophilin A in human periodontitis

2013 ◽  
Vol 48 (5) ◽  
pp. 615-622 ◽  
Author(s):  
L. Liu ◽  
C. Li ◽  
J. Xiang ◽  
W. Dong ◽  
Z. Cao
Keyword(s):  
Potential Role ◽  
Cyclophilin A ◽  
Over Expression
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