Abstract 1129: Obesity-related Elevations in Soluble P-selectin are Derived From Endothelium and Dependent on Expression of Leukocyte P-selectin Glycoprotein Ligand-1

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Kevin J Wickenheiser ◽  
Peter F Bodary ◽  
Kristina Bahrou ◽  
Daniel T Eitzman
Keyword(s):  
Bone Marrow ◽  
Body Weight ◽  
Leptin Receptor ◽  
The Body ◽  
Wild Type ◽  
Post Transplant ◽  
Time Period ◽  
Increased Risk ◽  
Soluble P ◽  
Deficient Mice

Background : Obesity is associated with proinflammatory changes and an increased risk for vascular disease complications. The tissue source and mechanism by which soluble P-selectin (sPsel) is generated in obesity are unclear. Methods and Results : Soluble p-selectin (sPsel) levels were measured in the circulation from lean wild type and obese leptin receptor deficient mice (LepR−/−) at 4 and 10 weeks of age. In wild-type mice body weight increases from 13+/−2 to 20+/−3 grams over this time period while the body weight increases from 15+/−2 to 38+/−5 grams in LepR−/− mice. At 4 weeks of age sPsel levels were 103+/−8mg/mL in wild-type mice vs. 138+/−9 ng/mL in LepR−/− mice, p=0.048. By 10 wks of age sPsel increased to 112 +/− 2 in wild-type mice and 182 +/− 9 in LepR−/− mice, p=0.00005. In order to determine if the obesity-induced rise in sPsel is regulated by leukocyte Psgl-1, bone marrow transplantation was performed from Psgl+/+ or Psgl−/− donors into irradiated LepR−/−recipients. At 4 weeks post-transplant, sPsel levels were 166 +/−6 ng/mL in LepR−/− mice receiving Psgl+/+ marrow and 45 +/− 4 ng/mL in LepR−/− mice receiving Psgl−/− marrow, p=0.0000004. In order to determine if the sPsel in LepR−/− mice originated from the endothelium versus platelets, we transplanted Psel−/− bone marrow into irradiated LepR−/−mice. At 4 weeks post transplant, sPsel levels were 153 +/−3 ng/mL in LepR−/− mice receiving Psel−/− bone marrow and were not significantly different from LepR−/− mice receiving Psel+/+ bone marrow (166 +/−6 ng/mL, p=0.06). By 10 weeks post transplant, mice gained even more weight and levels were 377+/−51 ng/mL in LepR−/− mice receiving Psel+/+ bone marrow and 370+/−73 ng/mL in LepR−/− mice receiving Psel−/− bone marrow, p=0.87. Conclusions : These data suggest that the increase in sPsel observed in obesity is primarily derived from the endothelium and that this process is regulated by leukocyte Psgl-1.

Fetal Liver-Derived Stem Cells Ameliorate Immune Functions in Leptin Receptor-Deficient Mice

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5417-5417
Author(s):  
Ming Li ◽  
Yasushi Adachi ◽  
Susumu Ikehara
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Body Weight ◽  
Leptin Receptor ◽  
Conflicts Of Interest ◽  
Fetal Liver ◽  
The Body ◽  
Immune Functions ◽  
Glucose Levels ◽  
Blood Glucose Levels

Abstract Fetal liver (FL) contains hepatic stem cells, hematopietic stem cells, and mesenchymal stem cells, as well as pluripotent stem cells and very small embryonic-like stem cells. FL has thus been available as a source of stem cells for regenerative medicine. Our previous report suggested that combining FL cell transplantation with the transplantation of fetal thymus prevented tumor growth in tumor-bearing mice. Moreover, in animal models, intra bone marrow-bone marrow transplantation (IBM-BMT) has proven to be the best approach for allogenic BMT. We here propose that transplanting FL cells by IBM-BMT can improve immune functions in leptin receptor-deficient (db/db) mice. FL cells were collected from FLs of C57BL/6 mice at 16 days post coitum, and then transplanted by IBM-BMT to leptin receptor deficent mice, an animal model of type 2 diabetes with obesity. Our results showed that the body weight was significantly lowered in the treated db/db mice than in the sham-treated db/db mice. The plasma IL-6 level significantly decreased and adiponectin level significantly increased after the transplantation of FL cells. Blood glucose levels also significantly decreased although not to within the normal range. This is the first report that the transplantation of FL cells may improve immune function, resulting in increased adiponectin levels, and decreased body weight in db/db mice. Disclosures No relevant conflicts of interest to declare.

Roux-en-Y Gastrointestinal Bypass Promotes Activation of TGR5 and Peptide YY

2020 ◽  
Vol 20 (8) ◽  
pp. 1262-1267
Author(s):  
Haojun Yang ◽  
Hanyang Liu ◽  
YuWen Jiao ◽  
Jun Qian
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Metabolic Diseases ◽  
Peptide Yy ◽  
The Body ◽  
Wild Type ◽  
L Cells ◽  
Body Weights ◽  
Gastrointestinal Bypass ◽  
G Protein Coupled

Background: G protein-coupled bile acid receptor (TGR5) is involved in a number of metabolic diseases. The aim of this study was to identify the role of TGR5 after Roux-en-Y gastric bypass (GBP). Methods: Wild type and TGR5 knockout mice (tgr5-/-) were fed a high-fat diet (HFD) to establish the obesity model. GBP was performed. The changes in body weight and food intake were measured. The levels of TGR5 and peptide YY (PYY) were evaluated by RT-PCR, Western blot, and ELISA. Moreover, the L-cells were separated from wild type and tgr5-/- mice. The levels of PYY in L-cells were evaluated by ELISA. Results: The body weights were significantly decreased after GBP in wild type mice (p<0.05), but not tgr5-/- mice (p>0.05). Food intake was reduced after GBP in wild type mice, but also not significantly affected in tgr5-/- mice (p>0.05). The levels of PYY were significantly increased after GBP compared with the sham group (p<0.05); however, in tgr5-/- mice the expression of PYY was not significantly affected (p>0.05). After INT-777 stimulation in L-cells obtained from murine intestines, the levels of PYY were significantly increased in L-cells tgr5+/+ (p<0.05). Conclusion: Our study suggests that GBP up-regulated the expression of TGR5 in murine intestines, and increased the levels of PYY, which further reduced food intake and decreased the body weight.

scholarly journals Maternal low-protein diet programmes offspring growth in association with alterations in yolk leptin deposition and gene expression in yolk-sac membrane, hypothalamus and muscle of developing Langshan chicken embryos

2009 ◽  
Vol 102 (6) ◽  
pp. 848-857 ◽  
Author(s):  
Kaiqing Rao ◽  
Jingjing Xie ◽  
Xiaojing Yang ◽  
Lei Chen ◽  
Roland Grossmann ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Weight ◽  
Leptin Receptor ◽  
Pectoralis Major Muscle ◽  
Yolk Sac ◽  
Pectoralis Major ◽  
The Body ◽  
Low Protein ◽  
Igf I ◽  
Offspring Growth

The present study was aimed to investigate the mechanism underlying the influence of maternal low-protein (LP) diet on offspring growth in the chicken. One hundred and twenty Chinese inbred Langshan breeder hens were allocated randomly into two groups fed diets containing low (10 %, LP) or normal (15 %) crude protein levels. Low dietary protein did not affect the body weight of hens, but significantly decreased the laying rate and egg weight. The yolk leptin content was significantly lower in eggs laid by LP hens, while no differences were detected for yolk contents of corticosterone, tri-iodothyronine (T3) or thyroxine. Despite significantly lower hatch weight, the LP offspring demonstrated obviously higher serum T3 concentration, which is in accordance with the faster post-hatch growth rate achieving significantly heavier body weight and pectoralis major muscle weight 4 weeks post-hatching. Expression of 20-hydroxysteroid dehydrogenase (20-HSD) mRNA in the yolk-sac membrane was significantly down-regulated at embryonic day 14, whereas that of transthyretin and leptin receptor (LepR) was not altered. Moreover, hypothalamic expression of 20-HSD, glucocorticoid receptors, thyrotropin-releasing hormone and LepR mRNA was significantly up-regulated in the LP group compared with their control counterparts. In the pectoralis major muscle, significantly higher expression of insulin-like growth factor (IGF)-I and IGF-I receptor mRNA was observed in LP embryos. The present study provides evidence that maternal LP diet programmes post-hatch growth of the offspring. The associated alterations in yolk leptin deposition as well as in yolk-sac membrane, fetal hypothalamus and muscle gene expression may be involved in mediating such programming effect in the chicken.

Esophageal Diameters in Children Correlated to Body Weight

2018 ◽  
Vol 29 (06) ◽  
pp. 528-532
Author(s):  
Thomas Sebastian Bott ◽  
Thekla von Kalle ◽  
Alexander Schilling ◽  
Oliver Heinz Diez ◽  
Sarah Besch ◽  
...  
Keyword(s):  
Body Weight ◽  
Pediatric Surgery ◽  
The Body ◽  
Lateral Aspect ◽  
Arithmetic Average ◽  
Upper Gi ◽  
Time Period ◽  
Upper Gastrointestinal ◽  
Weight Groups ◽  
Weight Percentile

Introduction The development of stenoses after correction of an esophageal atresia or acid and lye burn of the esophagus are well-known problems in pediatric surgery. Currently, stenoses are treated in the majority of cases by repeated balloon dilatations. The diameter of the balloons used is not standardized; standard curves do not exist. The aim of this study was to evaluate the diameter of the esophagus correlated to the body weight of the children as measured in upper gastrointestinal (GI) studies to answer the important question to what extent a stenosis should be dilated. Materials and Methods Within the time period from 2011 through 2016, 60 patients with upper GI studies were selected. Evaluations were blinded to two different examiners. The diameters were measured under maximum contrast filling between the second and third rib (cranial point of measurement) and between the seventh and eighth rib (caudal point of measurement). For both, the anteroposterior and lateral aspect was examined. The diameter was calculated as the arithmetic average of both measurements within one level. The diameters were correlated to the weight of the children. Results All children (n = 38) within the 3rd to 97th weight percentile were analyzed. Linear correlation and coefficients of 0.67 at the cranial point and 0.70 at the caudal point were found. Mean diameter at the cranial point of measurement was 6.75 mm at the lowest weight (2.6 kg) and 14 mm at 74 kg. Mean weight of these children (standard deviation [SD]) was 25.3 (18.8) kg and median age was 7 years. Within weight groups (0–10 kg; 10–20 kg; 20–35 kg; 35–50 kg; >50 kg), we calculated SD and two side tested critical 95% confidence interval for all measurements (n = 74). Conclusion Although the variation in measurements is considerable, this evaluation gives a reliable hint to which extent esophageal stenoses should be dilated in relation to the body weight. To the best of our knowledge, this is the first investigation to evaluate the diameter of the esophagus in children in relation to the body weight.

scholarly journals Co-Therapy of Pegylated G-CSF and Ghrelin for Enhancing Survival After Exposure to Lethal Radiation

2021 ◽  
Vol 12 ◽  
Author(s):  
Juliann G. Kiang ◽  
Min Zhai ◽  
Bin Lin ◽  
Joan T. Smith ◽  
Marsha N. Anderson ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Body Weight ◽  
Water Consumption ◽  
Bone Marrow Cells ◽  
The Body ◽  
Photon Radiation ◽  
Vehicle Group ◽  
Spleen Weight ◽  
Histopathological Analysis ◽  
Marrow Cells

Exposure to ionizing radiation (radiation injury, RI) in nuclear-related episode is evident to be life-threatening. RI occurs at levels of organs, tissues, cytosols, or nucleus. Their mechanisms are still not fully understood. FDA approves pegylated granulocyte colony-stimulating factor (Neulasta™, Peg-G-CSF) for acute hematopoietic syndrome and has been shown to save lives after lethal RI. We aimed to test whether Ghrelin enhanced Peg-G-CSF’s efficacy to save more lives after lethal RI. B6D2F1/J female mice were used for the study. They received 9.5 Gy (LD50/30 at 0.4 Gy/min) emitted from the 60Co-γ-photon radiation facility. Peg-G-CSF was injected subcutaneously at 1 mg/kg once on days 1, 8, and 15 after irradiation. Ghrelin contains 28 amino acid and is a hunger peptide that has been shown to stimulate food intake, promote intestinal epithelial cell proliferation, elevates immunity, inhibits brain hemorrhage, and increases stress-coping. Ghrelin was injected subcutaneously at 113 μg/kg once on days 1, 2, and 3 after irradiation. Survival, body weight, water consumption, hematology, spleen weight, splenocytes, bone marrow cells, and histology of bone marrow and ileum were performed. We observed that radiation resulted in 30-days survival by 30%. RI decreased their body weights and water consumption volumes. On the 30th day post-RI, platelets and WBCs such as basophils, eosinophils, monocytes, lymphocytes, neutrophils and leukocytes were still significantly decreased in surviving mice. Likewise, their RBC, hemoglobin, hematocrit, and splenocytes remained low; splenomegaly was found in these mice. Bone marrow in surviving RI animals maintained low cellularity with high counts of fat cells and low counts of megakaryocytes. Meanwhile, ileum histology displayed injury. However, mice co-treated with both drugs 24 h after RI resulted in 30-days survival by 45% above the vehicle group. Additionally, the body-weight loss was mitigated, the acute radiation syndrome was reduced. This co-therapy significantly increased neutrophils, eosinophils, leukocytes, and platelets in circulation, inhibited splenomegaly, and increased bone marrow cells. Histopathological analysis showed significant improvement on bone marrow cellularity and ileum morphology. In conclusion, the results provide a proof of concept and suggest that the co-therapy of Peg-G-CSF and Ghrelin is efficacious to ameliorate RI.

scholarly journals Endothelial leptin receptor mutation provides partial resistance to diet-induced obesity

2012 ◽  
Vol 112 (8) ◽  
pp. 1410-1418 ◽  
Author(s):  
Weihong Pan ◽  
Hung Hsuchou ◽  
Germaine G. Cornelissen-Guillaume ◽  
Bhavvani Jayaram ◽  
Yuping Wang ◽  
...  
Keyword(s):  
Body Weight ◽  
Partial Resistance ◽  
Heat Dissipation ◽  
Leptin Receptor ◽  
Wild Type ◽  
Blood Concentrations ◽  
Leptin Signaling ◽  
Metabolic Chamber ◽  
Diet Induced Obesity ◽  
Obesity And Diabetes

Leptin, a polypeptide hormone produced mainly by adipocytes, has diverse effects in both the brain and peripheral organs, including suppression of feeding. Other than mediating leptin transport across the blood-brain barrier, the role of the endothelial leptin receptor remains unclear. We recently generated a mutant mouse strain lacking endothelial leptin receptor signaling, and showed that there is an increased uptake of leptin by brain parenchyma after its delivery by in situ brain perfusion. Here, we tested the hypothesis that endothelial leptin receptor mutation confers partial resistance to diet-induced obesity. These ELKO mice had similar body weight and percent fat as their wild-type littermates when fed with rodent chow, but blood concentrations of leptin were significantly elevated. In response to a high-fat diet, wild-type mice had a greater gain of body weight and fat than ELKO mice. As shown by metabolic chamber measurement, the ELKO mice had higher oxygen consumption, carbon dioxide production, and heat dissipation, although food intake was similar to that of the wild-type mice and locomotor activity was even reduced. This indicates that the partial resistance to diet-induced obesity was mediated by higher metabolic activity in the ELKO mice. Since neuronal leptin receptor knockout mice show obesity and diabetes, the results suggest that endothelial leptin signaling shows opposite effects from that of neuronal leptin signaling, with a facilitatory role in diet-induced obesity.

scholarly journals Distinct Roles of Lymphotoxin α and the Type I Tumor Necrosis Factor (TNF) Receptor in the Establishment of Follicular Dendritic Cells from Non–Bone Marrow–derived Cells

1997 ◽  
Vol 186 (12) ◽  
pp. 1997-2004 ◽  
Author(s):  
Mitsuru Matsumoto ◽  
Yang-Xin Fu ◽  
Hector Molina ◽  
Guangming Huang ◽  
Jinho Kim ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Dendritic Cells ◽  
Tumor Necrosis ◽  
Type I ◽  
Follicular Dendritic Cells ◽  
Wild Type ◽  
Lymphotoxin Α ◽  
Deficient Mice ◽  
Necrosis Factor

In mice deficient in either lymphotoxin α (LT-α) or type I tumor necrosis factor receptor (TNFR-I), organized clusters of follicular dendritic cells (FDC) and germinal centers (GC) are absent from the spleen. We investigated the role of LT-α and TNFR-I in the establishment of spleen FDC and GC structure by using reciprocal bone marrow (BM) transfer. When LT-α–deficient mice were reconstituted with wild-type BM, FDC organization and the ability to form GC were restored, indicating that the LT-α–expressing cells required to establish organized FDC are derived from BM. The role of LT-α in establishing organized FDC structure was further investigated by the transfer of complement receptor 1 and 2 (CR1/2)–deficient BM cells into LT-α–deficient mice. Organized FDC were identified with both the FDC-M1 and anti-CR1 monoclonal antibodies in these BM-chimeric mice, indicating that these cells were derived from the LT-α–deficient recipient. Thus, expression of LT-α in the BM-derived cells, but not in the non–BM-derived cells, is required for the maturation of FDC from non-BM precursor cells. In contrast, when TNFR-I–deficient mice were reconstituted with wild-type BM, they showed no detectable FDC clusters or GC formation. This indicates that TNFR-I expression on non–BM-derived cellular components is necessary for the establishment of these lymphoid structures. TNFR-I–deficient BM was able to restore FDC organization and GC formation in LT-α–deficient mice, indicating that formation of these structures does not require TNFR-I expression on BM-derived cells. The data in this study demonstrate that FDC organization and GC formation are controlled by both LT-α–expressing BM-derived cells and by TNFR-I-expressing non–BM-derived cells.

Reduced Dose Lenalidomide Is Safe and Effective in Deletion (5q) MDS Patients with Severe Renal Impairment: Report of Two Cases.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4624-4624
Author(s):  
Stefan Knop ◽  
Hermann Einsele ◽  
Ralf Bargou ◽  
Denise Cosgrove ◽  
Alan List
Keyword(s):  
Bone Marrow ◽  
Renal Impairment ◽  
Renal Insufficiency ◽  
Blood Cell ◽  
The Body ◽  
World Health ◽  
Recombinant Erythropoietin ◽  
Unilateral Renal Agenesis ◽  
Increased Risk ◽  
Cytogenetic Remission

Abstract Introduction: Lenalidomide (Len) is highly active in the treatment of MDS with deletion 5q (del[5q]) (List et al. NEJM 2006). Patients with renal impairment have often been excluded from Len studies because of potential for delayed excretion with increased risk for adverse events. We present 2 MDS patients with 5q− syndrome and renal impairment who were treated with Len at reduced dosage. Patient 1: A 50-year-old woman presented with shortness of breath on exertion, pallor, and tachycardia. Laboratory tests showed hemoglobin (Hb) 3.9 g/dL with significant macrocytosis; white blood cell count (WBC) of 3.2 × 109/L; and creatinine 2.66 mg/dL (normal value, < 1.1 mg/dL). Bone marrow aspirate was consistent with World Health Organization 5q− syndrome. Abdominal ultrasound revealed unilateral renal agenesis. The patient required 2 packed red blood cell (RBC) units every 2 to 3 weeks. Glomerular filtration rate (GFR) was severely impaired (23 mL/min). Len was initiated at 5 mg/d and increased to 10 mg/d after 4 weeks. The patient showed a fast and sustained hematologic response, Hb of 10–11 g/dL without exogenous erythropoietin, and achieved transfusion independence within 6 weeks. Due to decreased WBC of 1.3 × 109/L, and a platelet count (plt) of 57 × 109/L, indicating thrombocytopenia, Len was adjusted to a daily alternating dose of 5 mg and 10 mg, respectively. Complete cytogenetic remission was achieved by 6 months of treatment. Patient 2: An 83-year-old female presented with sustained anemia despite treatment with recombinant erythropoietin. Bone marrow findings and peripheral blood features were consistent with the 5q− syndrome. The patient was transfusion dependent and received a single treatment cycle with azacitidine, but developed acute renal insufficiency, accompanied by an elevation in creatinine to 4.8 mg/dL. She continued supportive care measures receiving 2 units of RBC every 4 weeks. Len was initiated at 5 mg daily. GFR at start of therapy was moderately decreased (31 mL/min). After 6 weeks of treatment the patient developed a generalized rash, occupying 30–50% of the body, which subsided with temporary therapy cessation. Laboratory studies at 6 weeks revealed a WBC of 1.58 × 109/L, with an absolute neutrophil count (ANC) of 3.5 × 109/L, Hb of 12.3 g/dL and plt of 42 × 109/L. Because of progressive decline in the patient’s Hb levels Len was resumed 5 months later at a dose of 5 mg 3 times per week. This was well tolerated. Complete cytogenetic remission was achieved after 10 months of follow-up. Conclusions: These cases show that Len can be administered safely to MDS patients with renal insufficiency and with preserved clinical activity. In addition, the present observations suggest that Len therapy could abrogate the need for use of additional erythropoietin in these patients.

Stat3β Promotes Basal Granulopoiesis and Inhibits Emergency Granulopoiesis, While Stat3α Inhibits Basal Granulopoiesis and Promotes Emergency Granulopoiesis

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3871-3871
Author(s):  
Michele Redell ◽  
S. Wen-Wen Chen ◽  
Marcos J. Ruiz ◽  
David J. Tweardy
Keyword(s):  
Bone Marrow ◽  
B Lymphocyte ◽  
Inflammatory Responses ◽  
Bone Marrow Cells ◽  
Myeloid Cells ◽  
Lymphoid Cells ◽  
Transactivation Domain ◽  
Wild Type ◽  
Alternative Mrna Splicing ◽  
Deficient Mice

Abstract Signal transducer and activator of transcription 3 (Stat3) is a key signaling intermediate that is activated by several cytokines that regulate hematopoiesis, including granulocyte-colony stimulating factor (G-CSF), interleukin 6, and stem cell factor (SCF). Studies using mice with Stat3 deletion targeted to hematopoietic cells have shown that Stat3 negatively regulates basal granulopoiesis but positively regulates emergency granulopoiesis. Stat3 also has been reported to promote B lymphocyte differentiation. Defining the hematopoietic functions of Stat3 is further complicated by the existence of two isoforms: full-length Stat3α (p92), and truncated Stat3β (p83). Stat3β is derived from alternative mRNA splicing resulting in replacement of the C-terminal transactivation domain with 7 unique amino acids (CT7), which have been demonstrated to confer markedly prolonged nuclear retention. Homozygous Stat3α-deficient mice are not viable, whereas Stat3β-deficient mice survive to adulthood and are fertile, but have increased inflammatory responses compared to wild-type mice. We compared basal granulopoiesis and lymphopoiesis, as well as emergency granulopoiesis, in homozygous Stat3β-deficient mice (βΔ/βΔ), which express only Stat3α, vs. their wild-type (+/+) littermates. We found that βΔ/βΔ mice were significantly leukopenic (2880 ± 1260/ml v. 4600 ± 1670/ml; p<0.05), with lower absolute neutrophil counts (ANC, 360 ± 180/ml v. 800 ± 380/ml, p<0.05) and B lymphocyte counts (780 ± 470/ml v. 1830 ± 1260/ml, p<0.05), compared to +/+ mice. Within the circulating B-lymphocyte population, the mature B220hi/IgM− cells were most dramatically reduced (170 ± 70/ml v. 480 ± 350/ml, p<0.05). Percentages of myeloid and lymphoid cells in the spleen and bone marrow were not significantly different between βΔ/βΔ and +/+ mice. Bone marrow from βΔ/βΔ mice generated significantly fewer myeloid colonies (CFU-GM) compared to wild-type marrow (28 ± 9 v. 42 ± 8 colonies per 20,000 cells, p<0.05). Additionally, βΔ/βΔ lineage-depleted bone marrow cells cultured in G-CSF and SCF produced significantly fewer CD11b+/Gr1+ myeloid cells compared to +/+ cells (52.8 ± 6.5% v. 68.3 ± 2.6%, p<0.05). In contrast, bone marrow from βΔ/βΔ and +/+ mice produced equal numbers of pro-B colonies in CFU assays containing the lymphopoietic cytokine IL-7. Finally, as a test of emergency granulopoiesis, we administered a single dose of G-CSF (250 μg/kg subcutaneously) or an equal volume of PBS, and 24 hr later measured the ANC, percentage of CD11b+/Gr1+ myeloid cells in the bone marrow, and CFU-GM generation. Mice of both genotypes responded to G-CSF stimulation with increases in ANC, percent of myeloid cells within the marrow, and CFU-GM. Bone marrow from βΔ/βΔ mice showed a larger G-CSF-induced increase in CFU-GM (PBS: 22 ± 5 v. G-CSF: 39 ± 1, p<0.05) compared to +/+ marrow (PBS: 24 ± 14 v. G-CSF: 31 ± 14, NS). Thus, Stat3β positively regulates basal granulopoiesis in the bone marrow, and may negatively regulate emergency granulopoiesis. This pattern is the opposite of that seen with deletion of both Stat3 isoforms, indicating that Stat3α’s function is to negatively regulate basal granulopoiesis and positively regulate emergency granulopoiesis. Stat3β also positively regulates circulating B lymphocyte numbers, via a mechanism other than B lymphocyte production in the bone marrow.

Loss of P-Selectin Promotes the Function of Aged Hematopoietic and Leukemic Stem Cells.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1577-1577
Author(s):  
Yaoyu Chen ◽  
Sullivan Con ◽  
Yiguo Hu ◽  
Linghong Kong ◽  
Cong Peng ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Flow Cytometry ◽  
Stem Cell ◽  
Bone Marrow Cells ◽  
Leukemic Stem Cells ◽  
Wild Type ◽  
Post Transplant ◽  
Marrow Cells

Abstract Abstract 1577 Hematopoiesis is a tightly regulated biological process that relies upon complicated interactions between the blood cells and their microenvironment. Adhesion molecules like P-selectin are essential to hematopoiesis, and their dysregulation has been implicated in leukemogenesis. We have previously shown a role for P-selectin in chronic myeloid leukemia and demonstrated that in its absence the disease process accelerates. Recently, there has also been speculation that P-selectin may play a role in the aging hematopoietic stem cells (HSCs), as its expression in upregulated as a mouse ages. In this study, we show that the loss of P-selectin function dysregulates the balance of stem cells and progenitors and that these differences become more pronounced with age. We compared the percentages of HSCs, long-term (LT)-HSCs, short-term (ST)-HSCs, multipotent progenitors (MPPs), CMPs, GMPs and MEPs in bone marrow by flow cytometry between wild type (WT) and Selp-/- mice. An age-dependent LT-HSC expansion was observed in WT mice. However, this expansion was prevented by the loss of Selp as observed in Selp-/-mice. Further, we demonstrate that with age LT-HSCs in particular express more elevated levels of P-selectin. LT-HSCs and ST-HSC/MPPs were isolated from the bone marrow of young (2 months old) and old (15 months old) WT mice and examined P-selectin expression by FACS. A significant increase in P-selectin expression was observed in LT-HSCs of old mice, and this increase was not observed in the ST-HSC+MPP subpopulations. We also show that the loss of P-selectin gene has profound effects of stem cell function, altering the capacity of these cells to home. Despite impaired homing capacity, stem cells lacking P-selectin possess a competitive advantage over their wild type counterparts. Using a stem cell competition assay, HSCs derived from Selp-/- mice (CD45.2+) and WT control mice (CD45.2+GFP+) were mixed in 1:1 ratio and transplanted into irradiated WT recipients (CD45.1). The initial findings were potentially indicative of the ability of cells derived from GFP mice to more efficiently home and engraft. Despite this initial advantage, cells derived from Selp-/- eventually exhibited a competitive and statistically significant advantage over the cells derived from GFP mice. At 30 days post-transplant, 49.9±1.4% of the CD45.2 subpopulation was GFP+. At 86 days post-transplant, 25.7±3.3 % of the CD45.2 cells derived from the peripheral blood were GFP+. Similarly, 23.0±3.7% of the CD45.2 cells derived from the bone marrow of these mice were GFP+. Indeed, we demonstrate that recipients of P-selectin deficient bone marrow cells more efficiently repopulate the bone marrow than controls and that this advantage extends and expands in the long-term. Finally, we demonstrate that recipients of leukemic cells lacking P-selectin develop a more accelerated form of leukemia accompanied by significant increases in stem and progenitor cells. Bone marrow cells from donor WT and Selp-/- mice were infected with retrovirus expressing BCR-ABL-GFP, and irradiated WT recipients were transplanted with 2×105 of these transduced donor cells. At 14 days post-transplant, recipient mice from each of the groups were sacrificed, and bone marrow cells were harvested and analyzed by flow cytometry. Recipients of leukemic Selp-/- cells possessed 3.5-fold more LSCs than recipients of wild-type cells. There were 3.1-fold more LT-LSCs and 3.8-fold more ST-LSCs and MPPs in recipients of Selp-/- cells than WT cells. In addition, recipients of leukemic Selp-/- cells possessed significantly more CMP (16.9-fold) and MEP (4.5-fold) cells. Because P-selectin expression increases with age on LT-HSCs, we sought to determine the role that age plays in CML development and progression. Bone marrow cells derived from 15-month-old donor Selp-/- and WT mice were transduced with BCR-ABL, respectively, followed by transplantation of the transduced cells into recipient mice. All recipients of BCR-ABL transduced Selp-/- cells died by 23 days after induction of CML and had a median survival of 19 days, whereas recipients of the transduced WT cells survived significantly longer. This pro-leukemic role for cells lacking P-selectin expression is leukemic stem cell-specific rather than stromal cell-specific and supports an essential role for P-selectin on leukemic stem cells. Disclosures: No relevant conflicts of interest to declare.

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