Expression data from human femur marrow adipose tissue (fMAT) and subcutaneous white adipose tissue of the thigh (tsWAT)

The bone marrow (BM) is a major reservoir of resting memory T cells and long-lived plasma cells, capable of providing protection against recurrent infections. Whether the age-related accumulation of adipose tissue in the BM affects the functionality and maintenance of memory cells is not well understood. For the first time, we compare human femur marrow adipose tissue (fMAT) and subcutaneous white adipose tissue of the thigh (tsWAT) obtained from the same donors. Using microarrays, we show that fMAT significantly differs from tsWAT regarding specific gene expression profiles including inflammatory responses and adipogenesis. fMAT adipocytes express increased levels of pro-inflammatory molecules concomitant with an elevated generation of reactive oxygen species (ROS) and impaired function of plasma cells in the BM. The reduced expression of adipocyte-specific genes and a less mature adipocyte phenotype in fMAT, relative to tsWAT, suggests that fMAT has more immune regulatory functions. Our findings indicate that fMAT is a unique type of adipose tissue contributing to inflammation and impairment of plasma cell function. We used microarrays to detail the gene expression profil of fMat in comparison to tsWAT in regard to the inflammatory response, adipogenesis/fatty acid metabolism, and redox regulation, and identified distinct classes of up-regulated genes. Eight human female individuals were used. From each donor we received femur marrow adipose tissue and subcutaneous white adipose tissue. Bone marrow biopsies and subcutaneous fat were fragmented, treated with collagenase to digest the tissues, and afterwards single adipocytes were isolated. To ensure high purity of adipocyte samples for microarray analysis a customized EasySep® protocol using the EasySep® purple magnet (Stemcell Technology, Cat#18000) was applied to remove residual leukocytes, erythrocytes, endothelia, and mesenchymal cells. RNA was isolated from purified bone marrow and subcutaneous adipocytes using the RNeasy Lipid Tissue Mini Kit (Qiagen) including the reagent Qiazol according to the manufactures’ protocol. Furthermore, isolated total mRNA with a RIN value >7 was used for microarray analysis which was done by Eurofins Genomics AROS from Denmark using Affymetrix® Human Gene ST Array Plate (chip type: HuGene 2.1).