Page 143 - ebook

The Oxysterols 27-hydroxycholesterol influences

pools of hematopoietic stem and progenitor cells

Hee Seon Choi , Jayoung Kim , Soo-Yeon Woo and Dongjun Lee 1
1
1
1

1 Department of Convergence Medical Science, Pusan National University School of Medicine, Yangsan, Korea

Introduction Results

Oxysterols are oxygenated derivatives of cholesterol and, compared 27HC is crucial role for maintaining HSPC pools.

to cholesterol, contain an additional hydroxy, epoxide or ketone

group in the sterol nucleus, and/or a hydroxyl group in the side chain.

Oxysterol synthesize bile acid and steroid hormone. It regulate LK LKS HPC 10

estrogen receptor function and lipid metabolism through the liver X 2.0 *** 8 ***

receptor. Oxysterols have the cytotoxic, apoptotic, immune function. Con

But If these cholesterols’ levels go up and accumulate at the blood HSC Cell numbers (10 4 ) 1.5 Cell numbers (10 4 ) 6

vessel, It can cause atherosclerosis, heart attack and stroke. 1.0 4

27-hydroxy cholesterol(27HC) is a side chain oxysterol oxygenated at 0.5 Con Con

the 27 the carbon atom of cholesterol. 27HC also promotes Chol 2 Chol

27HC
atherosclerosis. It is associated with breast cancer metastasis, Chol 0.0 LKS 0 27HC

prostate cancer, glioblastoma, causing synaptic dysfunction in LK

hippocampal neurons, and impairing memory and cognitive abilities. 6 *** 8 ***

4 6

27HC Cell numbers (10 4 ) Cell numbers (10 4 ) 4

2 Con Con

cKit Chol 2 Chol

Sca1 CD48 CD150
0 27HC 0 27HC

HSC HPC

Representative flow cytometry analyses of HSC and HSPCs in BM cells after

24hr treatment of 27HC. The numbers of HSPCs after treatment of 27HC are

decreased.

27HC is dispensable for maintaining mature cells.

8 80
Cell numbers (10 4 )

6 60

4 Cell numbers (10 4 ) 40

2 Con 20 Con

Chol Chol

0 27HC 0 27HC

Monocytes Neutrophil

Stem cell niches are local tissue microenvironments that maintain 15 1.5

stem cells and regulate their function by producing factors that act

directly on stem cells. 10 1.0

We show that 27HC treatment in bone marrow niche can decrease Cell numbers (10 4 ) Cell numbers (10 4 )

the number of HSPCs. 27HC treatment also increased the ROS levels 5 0.5

in the HSPCs. Therefore, 27HC plays a crucial role in the HSPC Con Con

maintenance., but not affected hematopoietic mature cells. Chol Chol
0 27HC 0.0 27HC

B220 CD3

The numbers of hematopoietic mature cells after 24hr treatment of 27HC including
Methods monocytes, neutrophils, T cells, B cells were not reduced. Therefore, hematopoietic

mature cells are not affected by 27HC.

• Animals

Wild type C57BL/6J mice were used. 27HC treatment display increased levels of ROS from HSPCs.

• Flow cytometric analysis

Bone marrow cells were collected from femurs and tibias by flushing

with FACS buffer.

HSCs were detected using Sca1-PE, cKit-APC, CD150-PE-CY7 and

CD48-APC-CY7 antibodies. Progenitor cells were detected using

Sca1-PE, cKit-APC, CD34-FITC, CD16/32-PE-CY7 and CD127-APC-

eFluor780 antibodies. Lineage cells were detected using B220-PE,

CD3e-APC cy7, CD11b-PE cy7, Gr1-APC antibodies. ROS levels were

detected using DCFDA-FITC antibody.

The ROS levels were increased in hematopoietic stem and progenitor cells after

24hr treatment of 27HC.

Conclusion

✓ 27HC treatment in the hematopoietic stem and progenitor system promotes hematopoietic stem and progenitor cells diminution.

✓ 27HC treatment in bone marrow cells does not alter the numbers of hematopoietic mature cells.

✓ Therefore, 27HC is crucial role for maintain HSPC pools, not mature cells.

✓ 27HC can increase the ROS levels in hematopoietic stem and progenitor cells.