Pleiotrophin Improves Survival Following Radiation-Induced Myelosuppression and Mediates HSC Expansion Via Induction Of Ras Signaling

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1205-1205
Author(s):  
Heather A Himburg ◽  
Phuong L. Doan ◽  
Mamle Quarmyne ◽  
Mai Nakamura ◽  
Nelson J. Chao ◽  
...  
Keyword(s):  
Total Body Irradiation ◽  
Target Genes ◽  
Conflicts Of Interest ◽  
Therapeutic Potential ◽  
Erk Signaling ◽  
Ras Signaling ◽  
Heparin Binding ◽  
Total Body ◽  
Deficient Mice

Abstract Discovery of the mechanisms through which the bone marrow microenvironment stimulates hematopoietic regeneration following myelosuppression could lead to therapies to accelerate hematopoietic reconstitution in patients receiving chemotherapy, total body irradiation and stem cell transplantation. We have previously shown that treatment with pleiotrophin (PTN), a heparin-binding growth factor which is secreted by BM endothelial cells (ECs), causes a 10-fold expansion of murine long term-HSCs in culture (Himburg et al. Nat Med 2010). More recently, we demonstrated that PTN-deficient mice have a >10-fold deficit in LT-HSCs and hematopoietic regenerative capacity compared to PTN+/+ mice, suggesting an important role for PTN in maintaining the HSC pool in vivo (Himburg et al. Cell Reports 2012). In keeping with this, 100% of PTN-deficient mice died prior to day +30 following 700 cGy total body irradiation (TBI) compared to 30% mortality in irradiated, PTN+/+ mice (P<0.0001). In order to determine the therapeutic potential of PTN as a systemically deliverable agent to accelerate hematopoietic recovery following myelosuppression, we irradiated C57Bl6 mice with 700 cGy TBI followed by every other day dosing with PTN or saline through day +14. At day +30, 80% of the PTN-treated mice were alive compared to 30% survival in the irradiated, saline-treated group (P=0.03). Interestingly, systemic administration of PTN was equally effective at promoting the survival of irradiated mice when administered as late as 96 hrs post-TBI, suggesting that PTN promotes HSC regeneration after injury. Mechanistically, PTN treatment significantly decreased HSC apoptosis following ionizing radiation exposure (P=0.007), which may explain, at least in part, the mitigative effects of PTN treatment on survival from radiation injury. Furthermore, we have discovered that PTN treatment strongly induces elements of the Ras/MEK/ERK signaling cascade in HSCs, including phosphorylation of Grb2 and ERK1/2, while also increasing levels of the ERK1/2 target genes, phospho-Erf1 and Fra-1. Consistent with this finding, PTN-deficient mice have significantly decreased levels of phospho-ERK1/2 in BM HSCs, suggesting that deficient Ras/MEK/ERK signaling may explain, at least in part, the HSC deficit observed in PTN-deficient mice. Importantly, pharmacologic inhibition of Ras or MEK1/2 proteins or genetic inhibition of KRas in BM KSL cells significantly abrogated PTN-mediated expansion of BM KSL cells and CFU-GEMMs in culture (P<0.01 for total KSL cells and CFU-GEMMs). Taken together, these results suggest that PTN-mediated expansion of HSCs may be dependent upon activation of the Ras/MEK/ERK pathway and provide the basis for further studies to delineate the role of this pathway in mediating PTN effects on the HSC pool in vitro and in vivo. Disclosures: No relevant conflicts of interest to declare.

Extreme Heterogeneity Of Myeloablative Total Body Irradiation (TBI) Techniques Across Europe: A Survey Of Acute Leukemia Working Party Of The EBMT

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4565-4565
Author(s):  
Sebastian Giebel ◽  
Leszek Miszczyk ◽  
Krzysztof Slosarek ◽  
Leila Moukhtari ◽  
Fabio Ciceri ◽  
...  
Keyword(s):  
Total Body Irradiation ◽  
Conflicts Of Interest ◽  
Working Party ◽  
Treatment Modalities ◽  
In Vivo Dosimetry ◽  
Treatment Unit ◽  
Hematopoietic Stem ◽  
Total Body ◽  
Methodological Aspects

Background Total body irradiation (TBI) is widely used for conditioning prior to both allogeneic and autologous hematopoietic stem cell transplantation. Myeloablatitve doses of TBI are considered highly effective but also associated with relevant toxicity. Both, the efficacy and toxicity may depend on many methodological aspects of TBI. The goal of the survey was to explore current practice across centers collaborating in the European Group for Blood and Marrow Transplantation (EBMT). Methods The questionnaire sent to all EBMT centers included 19 questions regarding the doses used for myeloabaltive TBI, the way of fractionation, the modes of delivering the dose, type of immobilization, methods of dosimetry and organ shielding. 56 centers from 23 countries responded. Results All centers differ with regard at least one of the methodological aspects. The total dose of TBI used for myeloablative transplantation ranges from 8 to 14.4 Gy, the number of fractions ranges from 1 to 8, while the dose per fraction is 1.65 – 8 Gy. Altogether 16 modalities of dosing/fractionation have been identified with 6 x 2 Gy being the most frequent one (n=36, 64%). The dose rate in the axis of the beam ranges from 4.5 – 30 cGy/min (27 modalities; most frequently 18 cGy/min, 5%). The treatment unit is regular linac (n=51, 91%) or cobalt unit (n=5, 9%). Beams used for regular linac are 6 to 23 MV (most frequently 6 MV, n=26, 51%). The most frequent technique used for irradiation is “patient in one field” using two fields per fraction and two patient positions per fraction (n=36, 64%), however, altogether 11 modalities were described with regard to the technique, number of fields and positions per fraction. Source to surface distance is 2 to 5 m (most frequently 4 m; n=10, 18%). In 23 (41%) centers patients are immobilized during TBI, using 9 different types of device. Fifty-two centers (93%) measure acquired dose of irradiation using 5 types of detectors for in vivo dosimetry (most frequently semiconductors; n=37, 66%). Accepted discrepancy between planned and measured dose ranges from 1.5 to 10%. In 47 (84%) centers lungs are shielded during irradiation and lung density is considered for treatment planning. Maximum accepted dose for lungs ranges from 6 to 12 Gy. Additionally, in some centers lenses (14%), thyroid gland (7%), larynx (4%), kidneys (4%) and/or salivary glands (2%) are shielded. Conclusions TBI is an extremely heterogeneous treatment modality. Differences between centers regard all methodological aspects. Our findings should warrant caution in interpretation of clinical studies involving TBI. Further investigation is needed to evaluate whether differences between treatment modalities influence the efficacy and safety of the TBI procedure. Finally, efforts to standardize the method should be considered. Disclosures: No relevant conflicts of interest to declare.

Abstract 625: Targeting of Heparin Binding EGF-like Growth Factor (HBEGF) Suppresses Hyperlipidemia and Atherosclerosis in LDL Receptor Deficient Mice

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Sangderk Lee ◽  
Richard Lee ◽  
Mark Graham ◽  
Lihua Yang ◽  
Seonwook Kim ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Target Genes ◽  
Regulatory Element ◽  
Atherosclerotic Lesion ◽  
Cell System ◽  
Heparin Binding ◽  
Regulated Gene Expression ◽  
Deficient Mice

Objective: Elevation of apoB-containing lipoproteins is a well-established risk factor for the development of atherosclerosis. Previous reports showed that expression of heparin-binding EGF-like growth factor (HBEGF), a ligand of epidermal growth factor receptor (EGFR), is associated with atherosclerosis development. In this study, we examined in vivo effects of HBEGF targeting on hyperlipidemia-induced atherosclerosis by suppressing HBEGF expression using antisense oligonucleotide (ASO). Methods and Results: Female and male LDLR deficient mice were fed a high fat diet (HFD; 21% fat, 0.2% cholesterol) throughout the study. After 8 weeks of HFD feeding, mice were injected intraperitoneally with either control or HBEGF ASOs weekly for 12 weeks. At termination, we measured circulating lipid concentrations and atherosclerotic lesion size in the aorta. Compared to control ASO group, HBEGF ASO group had a significant reduction of circulating total cholesterol, triglyceride, and apoB-containing lipoprotein concentrations but no change of high-density lipoprotein (HDL) concentration. Importantly, HBEGF ASO injection significantly suppressed atherosclerosis in the aortic arch, thoracic, and abdominal aorta. HBEGF ASO suppressed sterol synthetic gene expression in the liver but elevated lipid contents in the liver. HBEGF gene silencing in a liver cell system induced downregulation of sterol regulatory element binding protein (SREBP) target genes including LDLR and Insig1. Conclusion: Targeting HBEGF using ASOs is an efficient approach to suppress dyslipidemia and hyperlipidemia-induced atherosclerosis. The differential gene expression analysis suggests that HBEGF ASO administration suppresses SREBP-regulated gene expression in the liver leading to downregulation of circulating cholesterol and TG concentrations.

Homeostasis and regeneration of the hematopoietic stem cell pool are altered in SHIP-deficient mice

Blood ◽  
2003 ◽  
Vol 102 (10) ◽  
pp. 3541-3547 ◽  
Author(s):  
Cheryl D. Helgason ◽  
Jennifer Antonchuk ◽  
Caroline Bodner ◽  
R. Keith Humphries
Keyword(s):  
Negative Regulator ◽  
Wild Type Littermate ◽  
Hematopoietic Stem ◽  
Cell Pool ◽  
Multipotent Progenitors ◽  
Important Negative Regulator ◽  
Total Body ◽  
Deficient Mice

AbstractSH2-containing inositol 5-phosphatase (SHIP) is an important negative regulator of cytokine and immune receptor signaling. SHIP-deficient mice have a number of hematopoietic perturbations, including enhanced cytokine responsiveness. Because cytokines play an important role in the maintenance/expansion of the primitive hematopoietic cell pool, we investigated the possibility that SHIP also regulates the properties of cells in these compartments. Primitive hematopoietic cells were evaluated in SHIP-deficient mice and wild-type littermate controls using the colony-forming unit-spleen (CFU-S) and competitive repopulating unit (CRU) assays for multipotent progenitors and long-term lympho-myeloid repopulating cells, respectively. Absence of SHIP was found to affect homeostasis of CFU-S and CRU compartments. Numbers of primitive cells were increased in extramedullary sites such as the spleen of SHIP-deficient mice, although total body numbers were not significantly changed. In vivo cell cycle status of the CRU compartment was further evaluated using 5-fluorouracil (5-FU). SHIP-deficient CRUs were more sensitive to 5-FU killing, indicating a higher proliferative cell fraction. More strikingly, SHIP was found to regulate the ability of primitive cells to regenerate in vivo, as CRU recovery was approximately 30-fold lower in mice that received transplants of SHIP-deficient cells compared with controls. These results support a major role for SHIP in modulating pathways important in homeostasis and regeneration of hematopoietic stem cells, and emphasize the importance of negative cytokine regulation at the earliest stages of hematopoiesis. (Blood. 2003;102:3541-3547)

scholarly journals Enhancing c-MYC degradation via 20S proteasome activation induces in vivo anti-tumor efficacy

2020 ◽  
Author(s):  
Evert Njomen ◽  
Theresa A. Lansdell ◽  
Allison Vanecek ◽  
Vanessa Benham ◽  
Matt P. Bernard ◽  
...  
Keyword(s):  
Therapeutic Strategy ◽  
Target Genes ◽  
Intrinsically Disordered Proteins ◽  
Therapeutic Potential ◽  
Human Cancer ◽  
Disordered Proteins ◽  
20S Proteasome ◽  
Intrinsically Disordered

SUMMARYEnhancing proteasome activity is a potential new therapeutic strategy to prevent the accumulation of aberrant high levels of protein that drive the pathogenesis of many diseases. Herein, we examine the use of small molecules to activate the 20S proteasome to reduce aberrant signaling by the undruggable oncoprotein c-MYC, to treat c-MYC driven oncogenesis. Overexpression of c-MYC is found in more than 50% of all human cancer but remains undruggable because of its highly dynamic intrinsically disordered 3-D conformation, which renders traditional therapeutic strategies largely ineffective. We demonstrate herein that small molecule activation of the 20S proteasome targets dysregulated intrinsically disordered proteins (IDPs), including c-MYC, and reduces cancer growth in vitro and in vivo models of multiple myeloma, and is even effective in bortezomib resistant cells and unresponsive patient samples. Genomic analysis of various cancer pathways showed that proteasome activation results in downregulation of many c-MYC target genes. Moreover, proteasome enhancement was well tolerated in mice and dogs. These data support the therapeutic potential of 20S proteasome activation in targeting IDP-driven proteotoxic disorders, including cancer, and demonstrate that this new therapeutic strategy is well tolerated in vivo.

Abstract W P93: MiR-122 Improves Stroke Outcomes after Middle Cerebral Artery Occlusion in Rats

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
DaZhi Liu ◽  
Glen C Jickling ◽  
Bradley P Ander ◽  
Heather Hull ◽  
Xinhua Zhan ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Messenger Rna ◽  
Target Genes ◽  
Conflicts Of Interest ◽  
Neurological Impairment ◽  
Artery Occlusion ◽  
Neuroprotective Effects ◽  
Genomic Studies

MicroRNA (miRNA) are recently discovered small (~22 nucleotides), non-coding RNA that regulate translation of messenger RNA (mRNA) to protein. Though there are only hundreds of miRNAs, each of them can potentially regulate hundreds of target genes, via base-pairing with complementary sequences in mRNA. This provides one approach that targets a single miRNA to have effects on multiple genes. Our previous genomic studies have demonstrated that miR-122 decreased significantly in blood of experimental strokes produced by middle cerebral artery (MCA) occlusion in rats as well as in blood of patients with ischemic strokes. Therefore, we hypothesized that elevating blood miR-122 has the potential for treating stroke. Using the newly developed in vivo polyethylene glycol-liposome based miRNA transfection system and rat suture MCAO occlusion model, we show that injection of chemically modified mimic miR-122 (600ug/rat, i.v.) through tail vein immediately after MCAO occlusion significantly decreases the neurological impairment and significantly attenuates brain infarct volumes. Ongoing studies are identifying the target genes that are associated with the neuroprotective effects of miR-122 following stroke. Acknowledgements: This study was supported by NIH grant R01NS066845 (FRS). There were no conflicts of interest.

SU-FF-T-260: In Vivo Dose Measurements for Total Body Irradiation Using Optically Stimulated Luminescent Dosimeters

2009 ◽  
Vol 36 (6Part12) ◽  
pp. 2580-2580 ◽  
Author(s):  
C Esquivel ◽  
M Smith ◽  
S Stathakis ◽  
A Gutiérrez ◽  
C Shi ◽  
...  
Keyword(s):  
Total Body Irradiation ◽  
Total Body ◽  
Optically Stimulated Luminescent Dosimeters ◽  
Dose Measurements

SU-E-T-85: Total Body Irradiation (TBI) Optically Stimulated Luminescence In Vivo Dosimetry

2013 ◽  
Vol 40 (6Part11) ◽  
pp. 223-223 ◽  
Author(s):  
C Holloway ◽  
S Mahendra ◽  
D Kaurin ◽  
L Sweeney
Keyword(s):  
Total Body Irradiation ◽  
Optically Stimulated Luminescence ◽  
In Vivo Dosimetry ◽  
Total Body

Abnormal Distribution of Erythroid Progenitors Populations in Mice Lacking p45 NF-E2.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1988-1988
Author(s):  
Jadwiga Gasiorek ◽  
Gregory Chevillard ◽  
Zaynab Nouhi ◽  
Volker Blank
Keyword(s):  
Bone Marrow ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Conflicts Of Interest ◽  
Globin Genes ◽  
Erythroid Progenitors ◽  
Erythroid Progenitor ◽  
Adult Mice ◽  
Deficient Mice

Abstract Abstract 1988 Poster Board I-1010 The NF-E2 transcription factor is a heterodimer composed of a large hematopoietic-specific subunit called p45 and widely expressed 18 to 20-kDa small Maf subunits. In MEL (mouse erythroleukemia) cells, a model of erythroid differentiatin, the absence of p45 is inhibiting chemically induced differentiation, including induction of globin genes. In vivo, p45 knockout mice were reported to show splenomegaly, severe thrompocytopenia and mild erythroid abnormalities. Most of the mice die shortly after birth due to haemorrhages. The animals that survive display increased bone, especially in bony sites of hematopoiesis. We confirmed that femurs of p45 deficient mice are filled with bone, thus limiting the space for cells. Hence, we observed a decrease in the number of hematopoietic cells in the bone marrow of 3 months old mice. In order to analyze erythroid progenitor populations we performed flow cytometry using the markers Ter119 and CD71. We found that p45 deficient mice have an increased proportion of early erythroid progenitors (proerythroblasts) and a decreased proportion of late stage differentiated red blood cells (orthochromatic erythroblasts and reticulocytes) in the spleen, when compared to wild-type mice. We showed that the liver of p45 knockout adult mice is also becoming a site of red blood cell production. The use of secondary sites, such as the spleen and liver, suggests stress erythropoiesis, likely compensating for the decreased production of red blood cells in bone marrow. In accordance with those observations, we observed about 2 fold increased levels of erythropoietin in the serum of p45 knockout mice.Overall, our data suggest that p45 NF-E2 is required for proper functioning of the erythroid compartment in vivo. Disclosures: No relevant conflicts of interest to declare.

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