Project description:Human adipose tissue derived stem cells were differentiated to adipocytes in vitro. At the end of differentiation, cells were treated with siRNA targeting CD248 followed by exposure to 1% oxygen levels. Microarray analysis were performed to identify differentially regulated genes.
Project description:In the obese state, as adipose tissue expands, adipocytes become hypoxic and dysfunctional, leading to changes in the pattern of secreted proteins. To better understand the role of hypoxia in the mechanisms linked to obesity, we comparatively analyzed the secretome of differentiated 3T3-L1 adipocytes exposed to normoxia or hypoxia for 24 h. Proteins secreted into the culture media were precipitated using trichloroacetic acid and then digested by trypsin. Peptides were labeled by dimethyl labeling and analyzed by reversed phase nanoscale liquid chromatography coupled to a quadrupole Orbitrap mass spectrometer. Among factors downregulated in hypoxic conditions, we identified Decorin, a member of the leucine-rich proteoglycan family, Tissue Inhibitor of Metalloproteinase-2, Thrombospondin 1 and 2, all multifunctional proteins involved in extracellular matrix (ECM) homeostasis, and angiogenesis. Most findings were confirmed by expression studies of the relative genes in parallel experiments in vitro, in differentiated 3T3-L1 adipocytes, and in vivo, in fat tissues from obese vs. lean rats. Our observations are compatible with the concept that hypoxia may be an early trigger for ECM remodeling and angiogenesis in adipose tissue.
Project description:Obesity is characterised by expansion of white adipose tissue, accompanied by an inflamatory response. It has been proposed that the inflammatory state observed may be linked to relative hypoxia in clusters of adipocytes distant from vasculature. Adipose tissue hypoxia has been observed in both animal models and human studies in obesity, and has been linked to insulin resistance. This study has used Agilent whole-genome microarrays to examine the effects of acute hypoxia on the global gene expression in human adipocytes. Human adipocytes (Zen-bio cells) were incubated in hypoxic conditions (1% O2) for 24 h. Control human adipocytes were incubated under normoxic conditions (21% O2). Eight biological replicates were prepared for each experimental condition, and RNA was pooled from two biological replicates, giving a total of n=4 array replicates.
Project description:To investigate the function of YBX1 in the regulation of brown adipose aging, differentiated C3H10T1/2 brown adipocytes were transfected with specific siRNAs targeting YBX1 or control siRNA. Total RNA was extracted at 48h after transfection to performed gene expression profiling analysis by high throughput RNA-seq.
Project description:<p>Cell culture is generally considered to be hyperoxic. However, the importance of cellular oxygen consumption is often underappreciated, with rates of oxygen consumption often sufficient to cause hypoxia at cell monolayers. We initially focused on cultured adipocytes as a terminally differentiated cell-type with substantial oxygen consumption rates to support diverse cellular functions. Under standard conditions, cultured adipocytes are hypoxic and highly glycolytic. Increasing oxygen diverted glucose flux toward mitochondria and resulted in thousands of gene expression changes that pointed toward alleviated physiological transcriptional responses to hypoxia. Phenotypically, providing more oxygen increased adipokine secretion and rendered adipocytes more sensitive to insulin and lipolytic stimuli. The functional benefits of increasing pericellular oxygen were transferable to other cellular systems including hPSC-derived hepatocytes and cardiac organoids. Our findings suggest that oxygen is limiting in many terminally-differentiated cell culture systems, and that controlling oxygen availability can improve the quality and translatability of cell models.</p>
Project description:Post-injury remodeling is a complex process involving temporal specific cellular interactions in the injured tissue where the resident fibroblasts play multiple roles, including inflammation induction and tissue remodeling. To dissect the molecular basis of these interactions, we performed single-cell and spatial transcriptome analysis in human and mouse hearts after myocardial infarction. A subset of fibroblasts identified by unique high expression of CD248 was strongly correlated with collagen synthesis and remodeling, and genetic deletion of CD248 in fibroblast ameliorated cardiac fibrosis and dysfunction following ischemia/reperfusion, highlighting the functional importance of CD248 positive fibroblasts in post-injury pathological remodeling. CD248 stabilizes TGF-βR Ⅰ protein and activates ACKR3 expression in fibroblast, leading to enhanced T cell adhesion and retention. This CD248 mediated fibroblast-T cell interaction is required to sustain fibroblast activation and scar expansion in injured heart. Disruption of this interaction using monoclonal antibody or Chimeric antigen receptor T cell reduces T cell infiltration, ameliorates ischemia/reperfusion-induced cardiac fibrosis and improves heart function. Therefore, single cell and spatial molecular profiling in post-injury heart has uncovered a CD248 specific subclass of fibroblast with a critical role in fibroblast-T cell interaction and a new potential therapy to treat tissue fibrosis.
Project description:Obesity is characterised by expansion of white adipose tissue, accompanied by an inflamatory response. It has been proposed that the inflammatory state observed may be linked to relative hypoxia in clusters of adipocytes distant from vasculature. Adipose tissue hypoxia has been observed in both animal models and human studies in obesity, and has been linked to insulin resistance. This study has used Agilent whole-genome microarrays to examine the effects of acute hypoxia on the global gene expression in human adipocytes.
Project description:Adipose tissue in the mammary gland undergoes dramatic remodeling during reproduction. Adipocytes are replaced by mammary alveolar structures during pregnancy and lactation, then reappear upon weaning. Here, we reveal that adipocytes in the mammary gland de-differentiate into Pdgfrα+ preadipocyte- and fibroblast-like cells during pregnancy, and remain de-differentiated during lactation. Upon weaning, de-differentiated fibroblasts proliferate and re-differentiate into adipocytes. In order to determine the molecular signature of these de-differentiated adipocytes in the mammary gland, we compared these cells with classical adipocytes. Using the AdipoChaser-mT/mG system, we pre-labeled mature adipocytes with GFP expression to characterize the features of these de-differentiated adipocytes (Figure 4A), and then purified CD31-/CD45-/PDGFRα+/Tomato+ and CD31-/CD45-/PDGFRα+/GFP+ cells from the stromal vascular fraction (SVF) of lactating mammary gland at the peak of lactation through FACS. Gene expression analyses showed that the CD31-/CD45-/PDGFRα+/Tomato+ cells were indeed enriched with Tomato expression, while the CD31-/CD45-/PDGFRα+/GFP+ cells were enriched with GFP expression (Figure 4C). We then collected CD31-/CD45-/PDGFRα+/GFP+ cells as single cells for subsequent single cell RNA-sequencing analysis (Figure 4D-G, Supplemental. Figure S1A-G). After the flow sorting and single cell RNA amplification, 26 CD31-/CD45-/PDGFRα+/GFP+ cells passed the quality control, and these cells were used for single-cell RNA-sequencing analysis. Due to technical difficulties in sorting single mature white adipocyte through flow cytometry, adipocytes differentiated from the immortalized murine-derived brown pre-adipocyte cell line were used as mature adipocyte control (Pradhan et al., 2017). Additionally, we also included population RNA-seq experiments, i.e. three mature white adipocyte samples, two GFP+, and six GFP- ones.