JMIR Publications

ABSTRACT

Background:

Myelodysplastic syndrome (MDS) is a group of highly heterogeneous myeloid diseases. In the early stage of MDS, the infiltration density of macrophages and the iron load increased, and the expression level of IL-6 was up-regulated in bone marrow mesenchymal stem cells (BMSCs). We hypothesised that iron-overload macrophages are related to the expression of MSC-derived IL-6 and can mediate the survival and differentiation of aging and hematopoietic stem cells (HSCs) or hematopoietic progenitor cells (HPCs).

Objective:

This study aims to 1) clarify the phenotype and function of erythroid hematopoietic island macrophages; 2) determine whether iron-overloaded macrophages up-regulate the expression of IL-6 derived from MSCs and promote their senescence through the Keap1/Nrf2/ARE pathway, thereby affecting the survival and differentiation of HSCs/HPCs.

Methods:

H–E staining will be used to observe the basic morphology of bone marrow tissues, and Perls staining will be used to detect the iron staining intensity of macrophages. The expression of CD68+CD 169 +VCAM-1+ macrophages and EMPs in bone marrow tissues will be detected by confocal immunofluorescence microscopy and/or immunohistochemistry. The correlation between the results and clinical laboratory data will be analysed. Exosomes derived from iron-overloaded macrophages will be prepared. In addition, BMSCs will be cultured. The effects of 5 and 10 μg/mL of iron-overloaded macrophages and exosomes on IL-6 secretion, as well as the aging of BMSCs, will be observed. The expression of Keap1, Nrf2 and ARE in BMSCs will be also detected, and the changes in the expression level of iron-overloaded macrophages and exosomes, as well as the intervention of Nrf2 inhibitors, DRB transcriptional inhibitors 5, 6-dichloro-1-b-D- ribofuranosylbenzimidazole or dimethyl fumarate, will be observed. Descriptive statistical analysis will be expressed as mean ± standard deviation. Significant differences between two groups will be compared by using a t-test. Non-parametric testing will be used for non-normally distributed data.

Results:

Clinical and laboratory data is collecting.

Conclusions:

We intend to explore whether iron overload in macrophages mediates the expression and senescence of MSC-derived IL-6 through the Keap1/Nrf2/ARE pathway, thereby affecting the survival and differentiation of HSCs/HPCs. This is of great significance for clarifying the molecular mechanism of anemia in MDS and providing a theoretical basis for formulating diagnosis and treatment strategies for MDS.