S53Poster Presentations/ Experimental Hematology 42 (2014) S23–S68

P1120 - PROMISING CELL THERAPY ACHIEVES IMPROVEMENT

OUTCOMES

Laila Montaser and Sherin Fawzy

Menoufia University, College of Medicine, Shebin El-Kom, Egypt

Stem cell research is perhaps the most exciting medical technology of the twenty-first

century. The stem cell effort consists of technology development aimed at the produc-

tion, expansion, and differentiation of stem cells. Stem cells are progenitor cells that

are capable of self-renewal and differentiation into many different cell lineages. Stem

cells survive well and show stable division in culture, making them ideal targets for in

vitro manipulation. The researchers suggest potential future benefits of stem cells in

many fields of medicine. The potential application of stem cells is to form cells and

tissues for medical therapies. Stem cells offer a viable source of replacement cells to

treat diseases and can potentially reduce the morbidity and mortality for those await-

ing transplants. By directing stem cells to differentiate into specialized cell types,

there is the exciting possibility to provide a renewable source of replacement cells

for those suffering from diseases. Stem cells hold the promise of treatments and cures

for more than 70 major diseases and conditions that affect millions of people,

including diabetes, liver disease, arthritis, nerve disease, Alzheimer’s, cancer, multi-

ple sclerosis, spinal cord injuries, blindness, and HIV, as well as numerous genetic

disorders. This paper presents synopsis draws on some research studies to document

examples of researches on the application of cell therapy in some diseases.

P1121 - VERY LOW DOSES OF g-RADIATION LEAD TO LONG TERM

DEFECTS OF HEMATOPOIETIC STEM CELLS FUNCTIONS

Sarah Moreira, Daniel Lewandowski, Francoise Hoffschir, Stephanie Moreno,

Nathalie Gault, and Paul-Henri Romeo

CEA, Fontenay-aux-Roses, France

After exposure to g-radiation, hematopoietic stem cells (HSCs) are more prone to

survive than hematopoietic progenitors or mature cells. This radio-resistance is ac-

counted for by a strong activation of p53-mediated DNA Damage Response, and

by DNA repair through non-homologous end joining that leads to genomic instability.

These studies focused on the effects of moderate/high doses of g-radiation on HSCs,

but the effects of low doses (!0.1Gy) on HSCs are unknown. Here, we report HSCs

hyper-radiosensitivity at very low doses (0.02Gy) not associated with early DNA

damage, chromosomic aberration and apoptosis. Gene expression analysis of irradi-

ated LT-HSCs showed that the early response to low doses was p53 independent and

specifically regulated a set of genes linked to the Keap1/Nrf2 pathway, to adhesion

and to mitochondria function. In line with these results, Nrf2-/- LT-HSCs displayed

enhanced hyper-radiosensitivity, LT-HSCs irradiated at 0.02Gy have an initial

abnormal homing in vivo after transplantation, and a higher mitochondrial activity.

Finally, we showed that g-radiation of HSCs at 0.02Gy caused multiple long-term

defects in HSCs functions such as a decrease of the LT-HSCs pool without modifica-

tion of multilineage potential in the reconstituted bone marrow of recipient mice after

secondary transplantation and reduced tolerance to 5-FU treatment of the primary

transplanted mice. In contrast to high doses, the long-term effects of a 0.02Gy irra-

diation of LT-HSCs were not accounted for by genomic instability, but by a persistent

oxidative stress in LT-HSCs associated with an HSCs-transcriptional aging signature.

Altogether, these results showed, for the first time, the long term effects of doses of g-

irradiation as low as 0.02Gy on HSCs maintenance and suggested that low doses can

impair LT-HSCs function by altering mitochondria function, homing capacity and

ROS detoxification leading to a premature aging of LT-HSC. These alterations might

prime the stem cell to differentiate rather than self-renew leading to an exhaustion of

the LT-HSCs compartment.

P1122 - UNDERSTANDING THE MOLECULAR REGULATION OF

EOSINOPHIL PRODUCTION: A BASIS FOR INTERVENTION IN

INFLAMMATORY DISEASE

Clare Morgan1, Tracey Baldwin1, Marthe D’Ombrain1, Carolyn de Graaf2,

Jarny Choi1, Aaron Robinson1, Kerry Ramsay1, Don Metcalf1, Warren Alexander1,

and Douglas Hilton1

1Molecular Medicine, Walter & Eliza Hall Institute of Medical Research, Parkville,

Victoria, Australia; 2The Netherlands Cancer Institute, Amsterdam, Netherlands

Eosinophils are rare, specialized pro-inflammatory granulocytes. In the blood and pe-

ripheral organs of healthy individuals, eosinophils are important innate immune ef-

fectors, particularly for control of helminth and other parasitic infections. An

uncontrolled excess of tissue eosinophils can, however, cause considerable tissue

damage and this is responsible for disease pathology in asthma and other inflamma-

tory diseases. Increased numbers of eosinophils are common in the lungs and periph-

eral blood of asthma patients and there is strong evidence that eosinophils have an

active role in asthma pathogenesis. Some anti-eosinophil therapeutics have shown

promise in clinical trials; however, drug targets that entirely suppress eosinophil-

mediated inflammation remain to be identified. Despite their key roles in health

and disease, the cell biology and molecular regulation of eosinophil production

and function remain poorly characterized. We have refined the identity and potential

of cells committed to eosinophil development in vivo using detailed immunopheno-

typic characterization and have further defined the lineage potential of purified pop-

ulations of these progenitor subsets in in vitro semi-solid clonal cultures.

Additionally, we have generated detailed transcriptional profiles of eosinophil pro-

genitors and maturing eosinophils. Comparison of these data with profiles from other

haematopoietic lineages has yielded a suite of genes whose expression is enriched in

eosinophils. We are currently utilizing RNAi technology as part of a screen to iden-

tify novel regulators of eosinophil production and will present data from these exper-

iments. Candidate genes may themselves serve as new drug targets or as novel entry

points for development of anti-eosinophil therapeutics in asthma and other eosino-

phil-mediated inflammatory diseases.

P1123 - EFFECTS OF ADIPOGENIC CONDITIONS ON THE IN VITRO

GROWTH OF HUMAN HEMATOPOIETIC STEM AND PROGENITOR

CELLS FROM UMBILICAL CORD BLOOD

Angelica Mu~niz-Rivera-Cambas, Patricia Flores-Guzman, and Hector Mayani

IMSS National Medical Center, Mexico City, D.F., Mexico

It has been clearly demonstrated that the in vitro growth of hematopoietic stem and

progenitor cells (HSPC) depends on particular culture conditions that include the

presence of a variety of cytokines that promote their proliferation, expansion and dif-

ferentiation. To date, however, it is not known whether such cells are able to grow

under non-hematopoietic conditions. In trying to address this issue, the aim of this

study was to explore the effects of adipogenic conditions on the growth of human

HSPC from umbilical cord blood. A CD34+ CD38- Lin- cell population was obtained

and cultured for 21 days under four different protocols: 1) Adipogenic medium

throughout the whole culture period; 2) Hematopoietic medium for the first 7 days

and adipogenic medium for the rest of the culture period; 3) Hematopoietic medium

for the first 7 days, followed by 7 days under FBS-supplemented culture medium, and

adipogenic medium for the last 7 days; 4) Hematopoietic medium throughout the

entire culture. We found that, as compared to cultures in which hematopoietic me-

dium was present for the entire 21 days, cells grown in the presence of adipogenic

medium, under any of the indicated protocols, showed deficient proliferation and

expansion. In terms of the generation of cells with adipogenic features (intracellular

lipid content and expression of adipogenic genes), we found no differences between

cells grown in adipogenic conditions and those grown in hematopoietic conditions.

Indeed, cells under any of the conditions showed the presence of intracellular lipids

and mild expression of adipogenic genes (LPL and PPAR2). Interestingly, when a

pure macrophage cell population was assessed, similar results were obtained, sug-

gesting that macrophages were the cells responsible for these phenomena, and that

phagocytosis of lipids coming from death cells took place in culture. These results

indicate that, under our culture conditions, there seems to be no transdifferentiation

of human HSPC from umbilical cord blood into the adipogenic lineage.