Project description:Tumor-associated neutrophils are found in many types of cancer and are often reported to contribute to negative outcomes. Several studies have shown that the presence of TGF-β in the tumor microenvironment contributes to the skewing of neutrophils to have a more pro-tumor phenotype. However, the direct effects of TGF-β on neutrophil signaling and migration are unclear. We sought to characterize TGF-β signaling in both primary human neutrophils and the neutrophil-like cell line HL-60 and determine whether TGF-β directly induces neutrophil migration. We found that TGF-β1 does not induce neutrophil migration in either a transwell or an underagarose migration assay. However, TGF-β1 does activate signals canonically through SMAD3 and noncanonically through ERK1/2 in neutrophils in a time and dose-dependent manner. Additionally, TGF-β1 present in the tumor-conditioned media (TCM) is responsible for SMAD3 activation. Moreover, we discovered that TCM from aggressive breast cancer cells induces neutrophils to secrete leukotriene B4 (LTB4), which is a lipid mediator important for amplifying neutrophil recruitment. However, we found that TGF-β1 alone does not induce secretion of LTB4. We next performed RNA-sequencing to evaluate the effects of TGF-β1 and TCM on the neutrophil transcriptome. We found that TGF-β1 and TCM result in changes in gene transcription in HL-60 cells, specifically of two pro-tumor genes OSM and VEGFA. Together, our findings characterize the effects of TGF-β1 on neutrophil signaling, migration, and gene expression that can be applied to understanding the changes in neutrophils that occur in the tumor microenvironment.
Project description:Full development of IL-17 producing CD4+ T helper cells (TH17 cells) requires the transcriptional activity of both orphan nuclear receptors RORa and RORgt. Despite this evidence, RORa is considered functionally redundant to RORgt; thus, the function and therapeutic value of RORa in TH17 cells remains underexplored. Using mouse models of autoimmune and chronic inflammation, we show that expression of RORa is required for TH17 cell pathogenicity. T-cell specific deletion of RORa reduced the development of experimental autoimmune encephalomyelitis (EAE) and colitis. Reduced inflammation was associated with decreased TH17 cell development, lower expression of tissue-homing chemokine receptors and integrins, and increased frequencies of Foxp3+ T regulatory (Treg) cells. Importantly, inhibition of RORa with a selective small molecule antagonist largely phenocopied our genetic data, potently suppressing the in vivo development of both chronic/progressive and relapsing/remitting EAE but had no effect on overall thymic cellularity. Furthermore, use of the RORa antagonist effectively inhibited human TH17 cell differentiation and memory cytokine secretion. Together, these data suggest that RORa acts independently of RORgt in programming TH17 pathogenicity and identifies RORa as a safer and more selective therapeutic target for the treatment of TH17-mediated autoimmunity.
Project description:Proper differentiation of corneal epithelial cells (CECs) from limbal stem/progenitor cells (LSCs) is required for maintaining ocular homeostasis and clear vision. Here, using a single-cell transcriptomic atlas, we delineate the comprehensive and refined molecular regulatory dynamics during human CEC development and differentiation. We find that RORA is a CEC-specific molecular switch that initiates and drives LSCs to differentiate into mature CECs by activating PITX1. RORA dictates CEC differentiation by establishing CEC-specific enhancers and chromatin interactions between CEC gene promoters and distal regulatory elements. Conversely, RORA silences LSC-specific promoters and disrupts promoter-anchored chromatin loops to turn off LSC genes. Collectively, our work provides detailed and comprehensive insights into the transcriptional dynamics and RORA-mediated epigenetic remodeling underlying human corneal epithelial differentiation.
Project description:The retinoic acid receptor-related orphan receptor a (RORa) is a member of the NR1 subfamily of orphan nuclear hormone receptors. RORa is an important regulator of various biological processes, including cerebellum development, cancer and circadian rhythm. To determine molecular mechanism by which hepatic deletion of RORa induces obesity and insulin resistance, we performed global transcriptome analysis from high-fat diet (HFD)-fed RORa f/f and RORa LKO mouse liver tissues. This analysis provides insight into molecular mechanisms for RORa in high-fat-diet condition.
Project description:Proper differentiation of corneal epithelial cells (CECs) from limbal stem/progenitor cells (LSCs) is required for maintaining ocular homeostasis and clear vision. Here, using a single-cell transcriptomic atlas, we delineate the comprehensive and refined molecular regulatory dynamics during human CEC development and differentiation. We find that RORA is a CEC-specific molecular switch that initiates and drives LSCs to differentiate into mature CECs by activating PITX1. RORA dictates CEC differentiation by establishing CEC-specific enhancers and chromatin interactions between CEC gene promoters and distal regulatory elements. Conversely, RORA silences LSC-specific promoters and disrupts promoter-anchored chromatin loops to turn off LSC genes. Collectively, our work provides detailed and comprehensive insights into the transcriptional dynamics and RORA-mediated epigenetic remodeling underlying human corneal epithelial differentiation.