Figure 1.
Quantitative analysis of bone marrow adipocytes.
(a) Histology of the distal femurs of mice stained with hematoxylin and eosin. The top panels are from 6-month-old C57BL/6J male mice fed standard chow or high fat diet, and from 6-month-old ob/ob mice. The bottom panels are sections of distal femurs stained with hematoxylin and eosin from 14-month-old mice fed either standard chow or high fat diet. (b) Area of bone marrow fat infiltration as a % of total area. (c) Numbers of bone marrow fat cells (numbers/mm2 bone marrow). Fields were taken from distal femur sections of 6-month-old (C57BL/6J and ob/ob) and 14-month-old mice and calculated using ImagePro software. Data are mean ± SE of 6 to 10 mice per age group. * P< 0.05, ** P< 0.001 HFD vs. chow diet and ob/ob vs chow-fed 6-month old. P value was calculated by two tailed T-test.
Figure 2.
Diet induced obesity-mediated differential gene expression in bone marrow and epididymal adipocytes.
Bone marrow and epididymal adipocytes were isolated from the same mice (age 6 months, 14 months fed standard chow or high fat diet (HFD)). Cells from several animals were pooled to yield sufficient sample to analyze three arrays for each age and diet group and both adipocyte populations. A total of 24 arrays were included in this analysis. (a) Principal component analysis of array data before normalization showing clustering of bone marrow adipocytes as separate from epididymal adipocytes. (b) Supervised hierarchical cluster analysis of diet-induced obesity genes in 6- and 14-month-old in bone marrow and epididymal adipocytes. (c) Venn diagram of overlapped genes induced by a HFD in 6- and 14-month-old in bone marrow and epididymal adipocytes.
Figure 3.
Heat maps of adipocyte-specific pathways in bone marrow and epididymal adipocytes in response to a high fat diet.
(a) Clustering of genes involved in adipocyte differentiation (upper panel) and insulin receptor signaling (lower panel) with at least a 2-fold difference between standard chow and high fat diet in bone marrow and epididymal adipocytes. (b) Clustering of genes involved in decreased transmembrane potential of mitochondria (upper panel) and lipolysis (lower panel) with at least a 2-fold difference between standard chow and high fat diet in bone marrow and epididymal adipocytes.
Figure 4.
Heat maps of adipocyte-specific gene expression in bone marrow and epididymal adipocytes in 6-month-old diet-induced obese and ob/ob mice.
(a) Clustering of genes involved in adipocyte differentiation in 6-month old diet-induced obese (DIO) and ob/ob compared with standard chow fed lean mice in bone marrow (left) and epididymal (right) adipocytes. (b) Clustering of genes involved in lipolysis in 6-month old DIO and ob/ob mice compared with standard chow fed lean mice in bone marrow and epididymal adipocytes. (c) Clustering of genes involved in inflammation in 6-month old DIO and ob/ob mice compared with standard chow fed lean mice in bone marrow and epididymal adipocytes.