Project description:Primary human omental adipocytes were isolated from patients with non-cancer conditions. Subsequently, gene expression profiled in adipocytes and ovarian cancer cell line (SKOV3ip1) alone (control) or under co-culture conditions. Following co-culture cells were separated and total RNA isolated for microarray analysis.
Project description:Modifiable hydrogels have revealed tremendous insight into how physical characteristics of cells’ 3D environment drive stem cell lineage specification. However, in native tissues, cells do not passively receive signals from their niche. Instead they actively probe and modify their pericellular space to suit their needs, yet the dynamics of cells’ reciprocal interactions with their pericellular matrix when encapsulated within hydrogels remains relatively unexplored. Here, we show that human bone marrow stromal cells (hMSC) encapsulated within hyaluronic acid-based hydrogels modify their pericellular environment through degradation and/or protein secretion, imparting them with similar pericellular stiffnesses, regardless of initial hydrogel properties. These cell-secreted pericellular matrices play a role in regulating hMSC fate, with secretion of a stiff proteinaceous pericellular matrix associated with adipogenesis, and degradation with osteogenesis. Our observations suggest that hMSC participate in a bi-directional interplay between the properties of their 3D milieu and their own secreted pericellular matrix, and that this combination of interactions drives fate.
Project description:Circadian rhythms are daily physiological and behavioral changes governed by an internal molecular clock, and dysfunctions in circadian rhythms have long been associated with various neurodegenerative diseases. Abnormal sleep-wake cycle often precedes the onset of cognitive and motor symptoms in patients, while the pathological changes may further exacerbate the disturbance in circadian cycle. It is unclear whether dysregulated circadian rhythm is a consequence of, or a contributing factor for, neurodegeneration. In addition, the evidence directly connecting the neurodegeneration-associated proteins to core circadian clock gene expression remains sparse. Here we show that FUS, a RNA-binding protein implicated in the pathogenesis of ALS and frontotemporal dementia, exhibits a bi-directional regulation with circadian rhythm. Our meta-analysis of RNAseq datasets and subsequent biochemical analysis revealed FUS as a gene regulated by circadian oscillation. Furthermore, NR1D1 binds the FUS promoter and regulates the amplitude of FUS oscillation. Meanwhile, FUS is recruited by transcriptional co-repressor PSF, and is found in the same complex as Bmal-Clock to repress Per2 expression. More strikingly, in cells and brain tissues from homozygous knock-in rats, the pathogenic R521C mutant FUS significantly alters the oscillation patterns of core circadian genes even at young age. Therefore, our results have revealed a novel bi-directional mechanism whereby dysregulated circadian clock and FUS expression may exacerbate neurodegeneration via mutual influence.
Project description:Idiopathic pulmonary fibrosis (IPF) is the prototypic progressive fibrotic lung disease with a median survival of 2-4 years. Injury to and/or dysfunction of alveolar epithelium are strongly implicated in IPF disease initiation, but what factors determine why fibrosis progresses rather than normal tissue repair occurs remain poorly understood. We previously demonstrated that ZEB1-mediated epithelial-mesenchymal transition (EMT) in human alveolar epithelial type II (ATII) cells augments TGF-β-induced profibrogenic responses in underlying lung fibroblasts by paracrine signalling. Here we investigated bi-directional epithelial-mesenchymal crosstalk and its potential to drive fibrosis progression. RNA sequencing (RNA-seq) of lung fibroblasts exposed to conditioned media from ATII cells undergoing RAS-induced EMT identified many differentially expressed genes including those involved in cell migration and extracellular matrix (ECM) regulation. We confirmed that paracrine signalling between AS-activated ATII cells and fibroblasts augmented fibroblast recruitment and demonstrated that this involved a ZEB1-tissue plasminogen activator (tPA) axis. In a reciprocal fashion, paracrine signalling from TGF-β-activated lung fibroblasts or IPF fibroblasts induced RAS activation in ATII cells, at least partially via the secreted protein, SPARC. Together these data identify that aberrant bi-directional epithelial-mesenchymal crosstalk in IPF drives a chronic feedback loop that maintains a wound-healing phenotype and provides self-sustaining pro-fibrotic signals.
Project description:The cellular mechanisms by which PPARγ improves metabolism in mature human adipocytes and potential depot differences in its actions are poorly understood. To assess the global effects of PPARγ activation on human omental gene expression, we conducted microarray analysis of control vs. rosiglitazone-treated omental tissues from human subjects.
Project description:The fidelity of start codon recognition by ribosomes is paramount during protein synthesis. The textbook knowledge of eukaryotic translation initiation depicts 5’→3’ unidirectional migration of the pre-initiation complex (PIC) along the 5’UTR. In probing translation initiation from ultra-short 5’UTR, we report that an AUG triplet near the 5’ end can be selected via PIC backsliding. The bi-directional ribosome scanning is supported by competitive selection of closely spaced AUG codons and recognition of two initiation sites flanking an internal ribosome entry site. Transcriptome-wide PIC profiling reveals footprints with an oscillation pattern near the 5’ end and start codons. Depleting the RNA helicase eIF4A leads to reduced PIC oscillations and impaired selection of 5’ end start codons. Enhancing the ATPase activity of eIF4A promotes nonlinear PIC scanning and stimulates upstream translation initiation. The helicase-mediated PIC conformational switch may provide an operational mechanism that unifies ribosome recruitment, scanning, and start codon selection.
Project description:Our hypothesis is that in IBD patients intestinal bacteria translocation into the intra-abdominal fat depots affects adipocyte morphology and gene expression. The study aimed to study adipocyte gene expression of omental (OM) and mesenteric (MES) adipose tissue of ulcerative colitis (UC) and crohn's disease (CD). Total RNA was extracted from isolated adipocytes from omental and mesenteric adipose tissue of CD and UC patients. Microarray experiments were performed in duplicates of 4 different pools of RNAs extracted from adipocytes isolated from OM and MES of UC patients (n=5) and CD patients (n=5) respectively.
Project description:Technological advancements have enabled the design of increasingly complex engineered tissue constructs, which better mimic native tissue cellularity. Therefore, dissecting the bi-directional interactions between distinct cell types in 3D is necessary to understand how heterotypic interactions at the single-cell level impact tissue-level properties. We systematically interrogated the interactions between cardiomyocytes (CMs) and cardiac non-myocytes in 3D self-assembled tissue constructs in an effort to determine the phenotypic and functional contributions of cardiac fibroblasts (CFs) and endothelial cells (ECs) to cardiac tissue properties. One week after tissue formation, cardiac microtissues containing CFs exhibited improved calcium handling function compared to microtissues comprised of CMs alone or CMs mixed with ECs, and CMs cultured with CFs exhibited distinct transcriptional profiles, with increased expression of cytoskeletal and ECM-associated genes. However, one month after tissue formation, functional and phenotypic differences between heterotypic tissues were mitigated, indicating diminishing impacts of non-myocytes on CM phenotype and function over time. The combination of single-cell RNA-sequencing and calcium imaging enabled the determination of reciprocal transcriptomic changes accompanying tissue-level functional properties in engineered heterotypic cardiac microtissues.
Project description:Gestational diabetes mellitus (GDM) is considered as the early stage of type 2 diabetes mellitus. In this study, we compared the demographic and clinical data between six GDM and six NGT (healthy controls) and found the HOMA-IR was increased in GDM. Previously, many researches had proved that omental adipose tissues dysfunction could induce insulin resistance. Thus, in order to investigate the cause of the insulin resistance in GDM, label-free proteomics was used to discover differentially expressed proteins in omental adipose tissues between GDM and NGT. A total of 3529 proteins identified, including 66 significantly changed proteins. Adipocyte plasma membrane associated protein (APMAP also called C20orf3) was one of changed proteins and down regulated in GDM omental adipose tissues. Further, mature 3T3-L1 adipocytes were used to simulate omental adipocytes and we found that inhibited the expression of APMAP by RNAi would impaired the insulin signaling and activated the NFkB signaling in adipocytes. These results indicated that the decreased of APMAP in mental adipose tissues may be important in process of the insulin resistance in GDM.