SUMMARY An inducible gene expression program is a hallmark of the host inflammatory response. Recently, long intergenic non-coding RNAs (lincRNAs) have been shown to regulate the magnitude, duration, and resolution of these responses. Among these is lincRNA- Cox2, a dynamically regulated gene that broadly controls immune gene expression. To evaluate the in vivo functions of this lincRNA, we characterized multiple models of lincRNA-Cox2-deficient mice. LincRNA- Cox2-deficient macrophages and murine tissues had altered expression of inflammatory genes. Tran- scriptomic studies from various tissues revealed that deletion of the lincRNA-Cox2 locus also strongly impaired the basal and inducible expression of the neighboring gene prostaglandin-endoperoxide synthase (Ptgs2), encoding cyclooxygenase-2, a key enzyme in the prostaglandin biosynthesis pathway. By utilizing different genetic manipulations in vitro and in vivo, we found that lincRNA-Cox2 functions through an enhancer RNA mechanism to regulate Ptgs2. More importantly, lincRNA-Cox2 also functions in trans, independently of Ptgs2, to regulate critical innate immune genes in vivo.

Long non-coding RNAs are important regulators of biological processes including immune responses. The immunoregulatory functions of lncRNAs have been revealed primarily in murine models with limited understanding of lncRNAs in human immune responses. Here, we identify lncRNA LUCAT1 which is upregulated in human myeloid cells stimulated with lipopolysaccharide and other innate immune stimuli. Targeted deletion of LUCAT1 in myeloid cells increases expression of type I interferon stimulated genes in response to LPS. By contrast, increased LUCAT1 expression results in a reduction of the inducible ISG response. In activated cells, LUCAT1 is enriched in the nucleus where it associates with chromatin. Further, LUCAT1 limits transcription of interferon stimulated genes by interacting with STAT1 in the nucleus. Together, our study highlights the role of the lncRNA LUCAT1 as a post-induction feedback regulator which functions to restrain the immune response in human cells.

The nuclear long non-coding RNA LUCAT1 has previously been identified as a negative feedback regulator of type I interferon and inflammatory cytokine expression in human myeloid cells. Here, we define the mechanistic basis for the suppression of inflammatory gene expression by LUCAT1. Using comprehensive identification of RNA-binding proteins by mass spectrometry as well as RNA immunoprecipitation, we identified proteins important in processing and alternative splicing of mRNAs as LUCAT1-binding proteins. These included heterogeneous nuclear ribonucleoprotein C, M, and A2B1. Consistent with this finding, cells lacking LUCAT1 have altered splicing of selected immune genes. In particular, upon lipopolysaccharide stimulation, the splicing of the nuclear receptor 4A2 (NR4A2) gene was particularly affected. As a consequence, expression of NR4A2 was reduced and delayed in cells lacking LUCAT1. NR4A2-deficient cells had elevated expression of immune genes. These observations suggest that LUCAT1 is induced to control the splicing and stability of NR4A2, which is in part responsible for the anti-inflammatory effect of LUCAT1. Furthermore, we analyzed a large cohort of patients with inflammatory bowel disease as well as asthma and chronic obstructive pulmonary disease. In these patients, LUCAT1 levels were elevated and in both diseases, positively correlated with disease severity. Collectively, these studies define a key molecular mechanism of LUCAT1-dependent immune regulation through post-transcriptional regulation of mRNAs highlighting its role in the regulation of inflammatory disease.

Cancer metabolism is an intergrative ensemble of disrupted enzyme kinetics and dysregulated metabolite utilization leading to loss of normal cellular function that is the result of a multi-factorial yet coordinated breakdown in vascular, immune, cell cycle, apoptotic, and ECM components. In actively metabolizing cancer, the switch from mitochondrial OXPHOS to anaerobic glycolysis is very well characterized and understood. Global cellular changes in response to metabolic switch have either been overlooked or not been primary interest or relevance to cancer metabolism. We describe a novel systems biology/engineering approach encompassing cell models that are conditioned under various oncogenic perturbations or environments and then coupled with functional bioenergetic read out such as employing the XF24 Seahorse Bioscience analyzer, ATP assays, and ROS production. The OCR and ECAR measurements generated by XF24 analyzer enabled quantifying the switch from aerobic to the anerobic mode of energy metabolism. Cellular profiles were captured in the form of multi-omic (proteomic, genomic, proteomic) signatures using high-throughput mass spectrometry based protocols. Analyses were performed on oncogenic breast, prostate, liver, pancreatic, skin (melanoma, squamous cell carcinoma) and were compared to normal fibroblasts, keratinocytes, hepatocytes, kidney cells, adipocytes, and human aortic and endothelial cells. High throughput data cascades from various cancer states were integrated with the metabolic data from the XF24 analyzer using an AI-based data mining platform to generate causal network based on bayesian models (REFS™ model). The output enables the understanding of differential mechanisms that drive glycolysis and mitochondrial OXPHOS in a cancer versus normal environment. Further validation of prominent hub of activity as they partake as key drivers of metabolic end points by siRNA knockdown experiments followed by measurement using the XF24 analyzer confirmed the relevance of these hubs in cancer metabolism and their relevance as potential therapeutic targets and biomarkers for diagnostics development. The data output presented herein strongly suggest that the Interrogative Biology® platform is a key tool in deciphering differential network analysis pertinent to disease pathophysiology and bioenergetics. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4933. doi:1538-7445.AM2012-4933

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