Abstract 401: Functional Impact Of Rbfox1c In Cardiac Pathological Remodeling Through Targeted Mrna Stability Regulation

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Chen Gao ◽  
Zhaojun Xiong ◽  
Jianfang Liu ◽  
Nancy Cao ◽  
Tomohiro Yokota ◽  
...  

Post-transcriptional regulation plays a key role in transcriptome reprogramming during cardiac pathogenesis. In previous studies, we have identified that cardiac enriched RNA-binding protein, RBFox1 plays key role in cardiac hypertrophy through mRNA alternative splicing regulation in nuclei. However, RBFox1 gene also generates a cytosolic isoform (RBFox1c), suggesting additional functions of post-transcriptional regulation in heart. In adult heart, RBFox1c mRNA constituted ~ 40% of total RBFox1 level but was significantly repressed in pressure-overloaded failing mouse heart. Using CRISPR-Cas9 technology, we have established an isoform specific RBFox1c-cKO mouse. At baseline inactivation of RBFox1c led to decreased cardiac function along with induction of cardiac fibrosis. RBFox1c-cKO mice also showed macrophages infiltration into myocardium post 7days MI. In contrast, restoration of RBFox1c expression in adult intact hearts significantly reduced cardiac fibrosis post stress. RNA-seq analyses in RBFox1c expressing cardiomyocytes showed that RBFox1c specifically suppressed the expression of pro-inflammatory genes. Secondly, CLIP-Seq analysis and targeted RNA-IP showed that RBFox1c could directly interact with inflammatory pathway mRNAs. These results suggested the inflammatory mRNAs are direct downstream targets regulated by RBFox1c. Using both in vitro cultured cardiomyocytes and intact mouse hearts, we demonstrated that expression of RBFox1c reduces pro-inflammatory mRNA expression at baseline and upon hypertrophy stimulation. Lastly, we characterized the interactome of RBFox1c through proteomic analysis and found RBFox1c specifically interacted with a component of the RNA NMD machinery-Upf1. RBFox1c interaction with Upf1 in cardiomyocytes was diminished upon hypertrophic stress. Furthermore, by inactivation of Upf1 via siRNA, we demonstrated that RBFox1c mediated repression of proinflammatory genes was Upf1 dependent.RBFox1 regulates cardiac transcriptome reprogramming in two post-transcriptional processes via distinct isoforms. While the RBFox1n regulates RNA splicing, the RBFox1c functions through targeted mRNA repression of proinflammatory genes by recruitment of Upf1 mediated RNA degradation.

2017 ◽  
Vol 474 (10) ◽  
pp. 1669-1687
Author(s):  
Hiromi Motohashi ◽  
Yoshiki Mukudai ◽  
Chihiro Ito ◽  
Kosuke Kato ◽  
Toshikazu Shimane ◽  
...  

Although tumor protein D52 (TPD52) family proteins were first identified nearly 20 years ago, their molecular regulatory mechanisms remain unclear. Therefore, we investigated the post-transcriptional regulation of TPD52 family genes. An RNA immunoprecipitation (RIP) assay showed the potential binding ability of TPD52 family mRNAs to several RNA-binding proteins, and an RNA degradation assay revealed that TPD52 is subject to more prominent post-transcriptional regulation than are TPD53 and TPD54. We subsequently focused on the 3′-untranslated region (3′-UTR) of TPD52 as a cis-acting element in post-transcriptional gene regulation. Several deletion mutants of the 3′-UTR of TPD52 mRNA were constructed and ligated to the 3′-end of a reporter green fluorescence protein gene. An RNA degradation assay revealed that a minimal cis-acting region, located in the 78-280 region of the 5′-proximal region of the 3′-UTR, stabilized the reporter mRNA. Biotin pull-down and RIP assays revealed specific binding of the region to T-cell intracellular antigen 1 (TIA-1) and TIA-1-related protein (TIAR). Knockdown of TIA-1/TIAR decreased not only the expression, but also the stability of TPD52 mRNA; it also decreased the expression and stability of the reporter gene ligated to the 3′-end of the 78-280 fragment. Stimulation of transforming growth factor-β and epidermal growth factor decreased the binding ability of these factors, resulting in decreased mRNA stability. These results indicate that the 78-280 fragment and TIA-1/TIAR concordantly contribute to mRNA stability as a cis-acting element and trans-acting factor(s), respectively. Thus, we here report the specific interactions between these elements in the post-transcriptional regulation of the TPD52 gene.


2021 ◽  
Author(s):  
Jian-Rong Li ◽  
Mabel Tang ◽  
Yafang Li ◽  
Christopher I Amos ◽  
Chao Cheng

AbstractExpression quantitative trait loci (eQTLs) analyses have been widely used to identify genetic variants associated with gene expression levels to understand what molecular mechanisms underlie genetic traits. The resultant eQTLs might affect the expression of associated genes through transcriptional or post-transcriptional regulation. In this study, we attempt to distinguish these two types of regulation by identifying genetic variants associated with mRNA stability of genes (stQTLs). Specifically, we computationally inferred mRNA stability of genes based on RNA-seq data and performed association analysis to identify stQTLs. Using the Genotype-Tissue Expression (GTEx) lung RNA-Seq data, we identified a total of 142,801 stQTLs for 3,942 genes and 186,132 eQTLs for 4,751 genes from 15,122,700 genetic variants for 13,476 genes, respectively. Interesting, our results indicated that stQTLs were enriched in the CDS and 3’UTR regions, while eQTLs are enriched in the CDS, 3’UTR, 5’UTR, and upstream regions. We also found that stQTLs are more likely than eQTLs to overlap with RNA binding protein (RBP) and microRNA (miRNA) binding sites. Our analyses demonstrate that simultaneous identification of stQTLs and eQTLs can provide more mechanistic insight on the association between genetic variants and gene expression levels.Author SummaryIn the past decade, many studies have identified genetic variants associated with gene expression level (eQTLs) in different phenotypes, including tissues and diseases. Gene expression is the result of cooperation between transcriptional regulation, such as transcriptional activity, and post-transcriptional regulation, such as mRNA stability. Here, we present a computational framework that take advantage of recently developed methods to estimate mRNA stability from RNA-Seq, which is widely used to estimate gene expression, and then to identify genetic variants associated with mRNA stability (stQTLs) in lung tissue. Compared to eQTLs, we found that genetic variants that affects mRNA stability are more significantly located in the CDS and 3’UTR regions, which are known to interact with RNA-binding proteins (RBPs) or microRNAs to regulate stability. In addition, stQTLs are significantly more likely to overlap the binding sites of RBPs. We show that the six RBPs that most significantly bind to stQTLs are all known to regulate mRNA stability. This pipeline of simultaneously identifying eQTLs and stQTLs using only RNA-Seq data can provide higher resolution than traditional eQTLs study to better understand the molecular mechanisms of genetic variants on the regulation of gene expression.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Saikat Bhattacharya ◽  
Michaella J. Levy ◽  
Ning Zhang ◽  
Hua Li ◽  
Laurence Florens ◽  
...  

AbstractHeterogeneous ribonucleoproteins (hnRNPs) are RNA binding molecules that are involved in key processes such as RNA splicing and transcription. One such hnRNP protein, hnRNP L, regulates alternative splicing (AS) by binding to pre-mRNA transcripts. However, it is unclear what factors contribute to hnRNP L-regulated AS events. Using proteomic approaches, we identified several key factors that co-purify with hnRNP L. We demonstrate that one such factor, the histone methyltransferase SETD2, specifically interacts with hnRNP L in vitro and in vivo. This interaction occurs through a previously uncharacterized domain in SETD2, the SETD2-hnRNP Interaction (SHI) domain, the deletion of which, leads to a reduced H3K36me3 deposition. Functionally, SETD2 regulates a subset of hnRNP L-targeted AS events. Our findings demonstrate that SETD2, by interacting with Pol II as well as hnRNP L, can mediate the crosstalk between the transcription and the splicing machinery.


2019 ◽  
Vol 97 (1) ◽  
pp. 10-20 ◽  
Author(s):  
Laura P.M.H. de Rooij ◽  
Derek C.H. Chan ◽  
Ava Keyvani Chahi ◽  
Kristin J. Hope

Normal hematopoiesis is sustained through a carefully orchestrated balance between hematopoietic stem cell (HSC) self-renewal and differentiation. The functional importance of this axis is underscored by the severity of disease phenotypes initiated by abnormal HSC function, including myelodysplastic syndromes and hematopoietic malignancies. Major advances in the understanding of transcriptional regulation of primitive hematopoietic cells have been achieved; however, the post-transcriptional regulatory layer that may impinge on their behavior remains underexplored by comparison. Key players at this level include RNA-binding proteins (RBPs), which execute precise and highly coordinated control of gene expression through modulation of RNA properties that include its splicing, polyadenylation, localization, degradation, or translation. With the recent identification of RBPs having essential roles in regulating proliferation and cell fate decisions in other systems, there has been an increasing appreciation of the importance of post-transcriptional control at the stem cell level. Here we discuss our current understanding of RBP-driven post-transcriptional regulation in HSCs, its implications for normal, perturbed, and malignant hematopoiesis, and the most recent technological innovations aimed at RBP–RNA network characterization at the systems level. Emerging evidence highlights RBP-driven control as an underappreciated feature of primitive hematopoiesis, the greater understanding of which has important clinical implications.


2021 ◽  
Vol 22 (21) ◽  
pp. 11963
Author(s):  
Noof Aloufi ◽  
Aeshah Alluli ◽  
David H. Eidelman ◽  
Carolyn J. Baglole

Chronic obstructive pulmonary disease (COPD) is an incurable and prevalent respiratory disorder that is characterized by chronic inflammation and emphysema. COPD is primarily caused by cigarette smoke (CS). CS alters numerous cellular processes, including the post-transcriptional regulation of mRNAs. The identification of RNA-binding proteins (RBPs), microRNAs (miRNAs), and long non-coding RNAs (lncRNAs) as main factors engaged in the regulation of RNA biology opens the door to understanding their role in coordinating physiological cellular processes. Dysregulation of post-transcriptional regulation by foreign particles in CS may lead to the development of diseases such as COPD. Here we review current knowledge about post-transcriptional events that may be involved in the pathogenesis of COPD.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Maria Cimini ◽  
venkata naga srikanth garikipati ◽  
Andrea Elia ◽  
Chunlin Wang ◽  
MAY TRUONGCAO ◽  
...  

Superseding fibrosis through paracrine signals enhances the ventricular dysfunction aftermyocardial infarction (MI). We have earlier reported that within 2 days post-MI a cohort ofpodoplanin (PDPN), a platelet aggregation-inducing type I transmembrane glycoprotein,positive cells populate injured heart and enhance inflammatory response by physicalinteractions with monocytes. Here we explored whether exosomes from these cells couldindependently alter healthy heart physiology and structure. PDPN+ cells were isolated 2 daysafter MI, cultured expanded and activated with TNFα and AngiotensinII. Exosomes derived fromactivated PDPN+ cells conditioned media were used in vitro treatment of mouse cardiacendothelial cells (mCECs), mouse embryonic fibroblast (MEF) and monocytes and in vivo forthe treatment of healthy mouse hearts. PDPN+ cells derived exosomes (PDPN-exo)reprogramed mCECs to the lymphatic phenotype enhancing the expression of the majorlymphatic lineage markers and upregulated the expression of fibrotic markers suggesting anendothelial-mesenchymal transition. Furthermore, PDPN-exo drove the MEF to myo-fibroblastphenotype and monocytes toward pro-inflammatory phenotype. Proteomic analysis of PDPN-exo suggest these transitions may depend on NOTCH cleavage trough β-γSecretase. In vivo,PDPN-exo were initially injected into the left ventricle of healthy mouse hearts followed withexosomes boosters delivered by retro-orbital vein injection. Treated mice developed anextended epicardial fibrosis with a subsequent impairment in the contractility and increase ofthe end diastolic and systolic volumes. The fibrotic area was characterized by vessels doublepositive to endothelial and lymphatic endothelial markers, and infiltrating CD45+ cells. Inconclusion these data suggest that PDPN-exo alter the biology of mCECs, fibroblast andmonocytes and participate in adverse remodeling after MI; their specific cargo may representa cohort of targets for the treatment of cardiac fibrosis.


2000 ◽  
Vol 348 (2) ◽  
pp. 297-305 ◽  
Author(s):  
Shivalingappa K. SWAMYNATHAN ◽  
Ashok NAMBIAR ◽  
Ramareddy V. GUNTAKA

Y-Box proteins comprise a large family of multifunctional proteins with a wide spectrum of activities in both transcription and translational regulation of gene expression. Earlier, we have reported on the involvement of chk-YB-2 in transcriptional regulation of Rous sarcoma virus long terminal repeats and the involvement of chk-YB-1b in transcriptional regulation of alpha1(I) collagen genes. Here, we have investigated the potential role of chk-YB-2 and chk-YB-1b in RNA metabolism. We report that chk-YB-2 and chk-YB-1b are localized predominantly in the cytoplasm and that they both can bind single-stranded RNA in a sequence-specific and reversible manner. Well-conserved cold-shock domain, N-terminal proline-rich domain and the alternating clusters of acidic and basic amino acids located in the C-terminal ends of these two proteins were all found to be necessary for their RNA-binding ability. Further, we demonstrate that these two proteins inhibit translation in vitro and that binding to RNA is required for this inhibition. The significance of these results is discussed.


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