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Chronic inflammation is a major cause of disease. Inflammation resolution is in part directed by the differential stability of mRNAs encoding pro-inflammatory and anti-inflammatory factors. In particular, tristetraprolin (TTP)-directed mRNA deadenylation destabilizes AU-rich element (ARE)-containing mRNAs. However, this mechanism alone cannot explain the variety of mRNA expression kinetics that are required to uncouple degradation of pro-inflammatory mRNAs from the sustained expression of anti-inflammatory mRNAs. Here, we show that the RNA-binding protein CPEB4 acts in an opposing manner to TTP in macrophages: it helps to stabilize anti-inflammatory transcripts harboring cytoplasmic polyadenylation elements (CPEs) and AREs in their 3'-UTRs, and it is required for the resolution of the lipopolysaccharide (LPS)-triggered inflammatory response. Coordination of CPEB4 and TTP activities is sequentially regulated through MAPK signaling. Accordingly, CPEB4 depletion in macrophages impairs inflammation resolution in an LPS-induced sepsis model. We propose that the counterbalancing actions of CPEB4 and TTP, as well as the distribution of CPEs and AREs in their target mRNAs, define transcript-specific decay patterns required for inflammation resolution. Thus, these two opposing mechanisms provide a fine-tuning control of inflammatory transcript destabilization while maintaining the expression of the negative feedback loops required for efficient inflammation resolution; disruption of this balance can lead to disease. We thank the Biostatistics/Bioinformatics, Histopathology, Mouse Mutant, and Functional Genomics facilities at IRB Barcelona. The Flow Cytometry Facility of the UB/PCB and the CRG Genomic Unit are also acknowledged. We thank Dr. Mercedes Fernández and members of the labs of Dr. Angel Nebreda and Dr. Raul Méndez for useful discussion. This work was supported by grants from the Spanish Ministry of Economy and Competitiveness (MINECO, BFU2017-83561-P), the Fundación BBVA, the Fundación Bancaria 'la Caixa,' the Fundació La Marató TV3, and the Scientific Foundation of the Spanish Association Against Cancer (AECC). CS is the recipient of an FPI-Severo Ochoa fellowship from MINECO. IRB Barcelona is the recipient of a Severo Ochoa Award of Excellence from MINECO (Government of Spain) and was supported by the CERCA Programme (Catalan Government).

Summary Transcription and translation are two main pillars of gene expression. Due to the different timings, spots of action, and mechanisms of regulation, these processes are mainly regarded as distinct and generally uncoupled, despite serving a common purpose. Here, we sought for a possible connection between transcription and translation. Employing an unbiased screen of multiple human promoters, we identified a positive effect of TATA box on translation and a general coupling between mRNA expression and translational efficiency. Using a CRISPR-Cas9-mediated approach, genome-wide analyses, and in vitro experiments, we show that the rate of transcription regulates the efficiency of translation. Furthermore, we demonstrate that m6A modification of mRNAs is co-transcriptional and depends upon the dynamics of the transcribing RNAPII. Suboptimal transcription rates lead to elevated m6A content, which may result in reduced translation. This study uncovers a general and widespread link between transcription and translation that is governed by epigenetic modification of mRNAs., Graphical Abstract, Highlights • Transcription rates of mRNAs positively correlate with rates of their translation • Dynamics of RNA polymerase II impact the deposition of m6A on mRNAs • Suboptimal transcription enhances m6A modification of mRNAs • Excessive m6A modification is detrimental for the translation process, Slowly transcribed mRNAs show increased levels of N6-adenosine methylation and reduced translation efficiency, setting up a nuclear control on protein abundance.

BACKGROUND & AIMS: Vascular endothelial growth factor (VEGF) regulates angiogenesis, yet therapeutic strategies to disrupt VEGF signaling can interfere with physiologic angiogenesis. In a search for ways to inhibit pathologic production or activities of VEGF without affecting its normal production or functions, we investigated the post-transcriptional regulation of VEGF by the cytoplasmic polyadenylation element-binding proteins CPEB1 and CPEB4 during development of portal hypertension and liver disease. METHODS: We obtained transjugular liver biopsies from patients with hepatitis C virus-associated cirrhosis or liver tissues removed during transplantation; healthy human liver tissue was obtained from a commercial source (control). We also performed experiments with male Sprague-Dawley rats and CPEB-deficient mice (C57BL6 or mixed C57BL6/129 background) and their wild-type littermates. Secondary biliary cirrhosis was induced in rats by bile duct ligation, and portal hypertension was induced by partial portal vein ligation. Liver and mesenteric tissues were collected and analyzed in angiogenesis, reverse transcription polymerase chain reaction, polyA tail, 3' rapid amplification of complementary DNA ends, Southern blot, immunoblot, histologic, immunohistochemical, immunofluorescence, and confocal microscopy assays. CPEB was knocked down with small interfering RNAs in H5V endothelial cells, and translation of luciferase reporters constructs was assessed. RESULTS: Activation of CPEB1 promoted alternative nuclear processing within noncoding 3'-untranslated regions of VEGF and CPEB4 messenger RNAs in H5V cells, resulting in deletion of translation repressor elements. The subsequent overexpression of CPEB4 promoted cytoplasmic polyadenylation of VEGF messenger RNA, increasing its translation; the high levels of VEGF produced by these cells led to their formation of tubular structures in Matrigel assays. We observed increased levels of CPEB1 and CPEB4 in cirrhotic liver tissues from patients, compared with control tissue, as well as in livers and mesenteries of rats and mice with cirrhosis or/and portal hypertension. Mice with knockdown of CPEB1 or CPEB4 did not overexpress VEGF or have signs of mesenteric neovascularization, and developed less-severe forms of portal hypertension after portal vein ligation. CONCLUSIONS: We identified a mechanism of VEGF overexpression in liver and mesentery that promotes pathologic, but not physiologic, angiogenesis, via sequential and nonredundant functions of CPEB1 and CPEB4. Regulation of CPEB4 by CPEB1 and the CPEB4 autoamplification loop induces pathologic angiogenesis. Strategies to block the activities of CPEBs might be developed to treat chronic liver and other angiogenesis-dependent diseases. This work was supported by grants from the Spanish Ministry of Economy and Competitiveness (MINECO; SAF2011-29491 and SAF2014-55473-R to MF; BFU2011-30121, BFU2014-54122-P and Consolider RNAREG CSD2009-00080 to RM; PI13/00341 to JB; PI11/01562 and PI14/00125 to PN), Generalitat de Catalunya (SGR1436 to RM; SGR1108 to JB), Fundación Botín by Banco Santander through its Santander Universities Global Division (to RM), AECC Scientific Foundation (to RM and MF), Worldwide Cancer Research (to RM and MF) and RETIC Cancer RD12/0036/0051/FEDER to PN. GFM is funded by a Juan de la Cierva contract from MINECO. IRB Barcelona is the recipient of a Severo Ochoa Award of Excellence from MINECO (Government of Spain). CIBERehd is an initiative from the Instituto de Salud Carlos III. We also thank Dr Francisco X Real for his contribution to knockout mice generation.