Fig. 2: OLFM2 is a marker of adipocyte commitment.

a Pipeline diagram of in vitro differentiated human preadipocytes (PA) growing into lipid-containing mature adipocytes (MA). DM-2 (first) and AM-1 (second week and thereafter) stand for differentiation and adipocyte media, respectively. b Expression dynamics of OLFM2 during adipogenesis (n = 3 biological replicates for each day of hormonal stimuli), and c dynamic changes with regard to unstimulated precursor cells (n = 4/group/time point) and the expression of the others olfactomedin family protein members²¹. d OLFM2 (red) immunofluorescent staining captures in human PA (n = 4), differentiating adipocytes (Day 7; n = 4), and MA (n = 4 biological replicates). Nuclei are stained in blue (DAPI). White arrows point at the apparent perinuclear red signal in differentiating adipocytes. e, f MA showed less OLFM2 immunofluorescent staining signal when challenged with macrophage LPS-conditioned media (MCM; n = 4), as confirmed by g measures of gene expression in MA challenged with macrophage media (MM) or MCM (n = 4 biological replicates/group). The scale bars denote 100 μm length. h The scatter plot displays the expression (microarray) of transcripts coding for OLFM1-4, adiponectin (ADIPOQ), and pro-inflammatory interleukins (IL6 and IL1β) in inflamed Simpson Golabi Behmel syndrome (SGBS)-derived adipocytes, as explained in ref. ²². Red ink in labels depicts increased levels, and green labels show transcripts decreased in inflamed adipocytes. Blue labels for transcript with no significant variation. Bar plot shows expression of OLFM2 in human PA and MA from i lean (BMI < 25 kg/m²) and j sex, age and fat depot-matched donors with obesity, and changes in MA when challenged with TGFβ for 24 h (n = 4 biological replicates/group). k Variations in MA responding to LPS in the media (n = 6 replicates/group). In bar plots, results are presented as mean ± S.E.M. The box plots in c show center line at the median, upper and lower lines bound at 75th and 25th percentiles, respectively, and whiskers at minimum and maximum values. r.u. stands for relative units. *p < 0.05, **p < 0.01 (One-way ANOVA and Tukey’s multiple comparisons test). Source data are provided with the article as a Source data file. (l) Number of transcription factors (TF) affecting human olfactomedin coding genes, and m OLFM2 gene region ChIP-seq peaks for human datasets and TF in WashU EpiGenome Browser v40.6¹¹³. Only signal values for PPARG, CEBPB, and CREB1 (listed in red in Fig. 2l) are represented. n Mean TPM (transcript per million), detectability (TPM > 0.1%), and heat map of pairwise Spearman correlation coefficients for OLFM2 (ENSG00000105088) and reference genes for different populations of adipose tissue resident cells, in the case of adipocytes (AC), ADIPOQ, LIPE and PLIN1. The lack of values for mesothelial cells (MesoC) and neutrophils (NP) in SC adipose tissue is due to the low representation of these cell types, as explained in ref. ²⁵.