Interleukin 11 therapy causes acute heart failure and its use in patients should be reconsidered

Background Interleukin 11 (IL11) was initially thought important for platelet production, which led to recombinant IL11 being developed as a drug to treat thrombocytopenia. IL11 was later found to be redundant for haematopoiesis and its use in patients is associated with unexplained cardiac side effects. Here we identify previously unappreciated and direct cardiomyocyte toxicities associated with IL11 therapy. Methods We injected recombinant mouse lL11 (rmIL11) into mice and studied its molecular effects in the heart using immunoblotting, qRT-PCR, bulk RNA-seq, single nuclei RNA-seq (snRNA-seq) and ATAC-seq. The physiological impact of IL11 was assessed by echocardiography in vivo and using cardiomyocyte contractility assays in vitro . To determine the activity of IL11 specifically in cardiomyocytes we made two cardiomyocyte-specific Il11ra1 knockout mouse models using either AAV9-mediated and Tnnt2 -restricted (vCMKO) or Myh6 (m6CMKO) Cre expression and an Il11ra1 floxed mouse strain. In pharmacologic studies, we studied the effects of JAK/STAT inhibition on rmIL11-induced cardiac toxicities. Results Injection of rmIL11 caused acute and dose-dependent impairment of left ventricular ejection fraction (saline (2 µL/kg), 60.4%±3.1; rmIL11 (200 mcg/kg), 31.6%±2.0; p<0.0001, n=5). Following rmIL11 injection, myocardial STAT3 and JNK phosphorylation were increased and bulk RNA-seq revealed upregulation of pro-inflammatory pathways (TNFα, NFκB and JAK/STAT) and perturbed calcium handling. SnRNA-seq showed rmIL11-induced expression of stress factors ( Ankrd1 , Ankrd23 , Xirp2 ), activator protein-1 (AP-1) transcription factor genes and Nppb in the cardiomyocyte compartment. Following rmIL11 injection, ATAC-seq identified epigenetic enrichment of the Ankrd1 and Nppb genes and stress-responsive, AP-1 transcription factor binding sites. Cardiomyocyte-specific effects were examined in vCMKO and m6CMKO mice, which were both protected from rmIL11-induced left ventricular impairment and molecular pathobiologies. In mechanistic studies, inhibition of JAK/STAT signalling with either ruxolitinib or tofacitinib prevented rmIL11-induced cardiac dysfunction. Conclusions Injection of IL11 directly activates JAK/STAT3 in cardiomyocytes to cause acute heart failure. Our data overturn the earlier assumption that IL11 is cardioprotective and explain the serious cardiac side effects associated with IL11 therapy, which questions its continued use in patients. What is new? What are the clinical implications? ### Competing Interest Statement Stuart A. Cook is a co-inventor on a number of patent applications relating to the role of IL11 in human diseases that include the published patents: WO2017103108, WO2017103108 A2, WO 2018/109174 A2, WO 2018/109170 A2. Stuart A. Cook is also a co-founder and shareholder of Enleofen Bio PTE LTD and VVB PTE LTD. * AAV9 : Adeno-associated virus serotype 9 ANOVA : Analysis of variance AP-1 : Activator protein 1 ATACseq : Assay for transposase-accessible chromatin with sequencing Bpm : Beats per minute CM : Cardiomyocyte ECG : Electrocardiogram EGFP : Enhanced green florescent protein ERK : Extracellular signal regulated kinase FDR : False discovery rate FOSL2 : FOS like 2 GAPDH : Glyceraldehyde-3-phosphate dehydrogenase GCS : Global circumferential strain GSEA : Gene set enrichment analysis HR : heart rate IL6 : Interleukin 6 IL11 : Interleukin 11 IL11RA1 : Interleukin 11 receptor A1 IP : Intraperitoneal JAK : Janus kinase JNK : c-Jun N-terminal kinase KEGG : Kyoto encyclopaedia of genes and genomes LV : Left ventricle LVEF : Left ventricular ejection fraction PBS : Phosphate buffered saline PCR : Polymerase chain reaction PSAX : Parasternal short axis QPCR : Quantitative polymerase chain reaction rhIL11 : Recombinant human interleukin 11 RIPA : Radioimmunoprecipitation assay buffer rmIL6 : Recombinant mouse interleukin 6 rmIL11 : Recombinant mouse interleukin 11 SEM : Standard error of the mean STAT : Signal transducer and activator of transcription TNFα : Tumour necrosis factor-alpha UMAP : Uniform Manifold Approximation and Projection vCMKO : Viral mediated cardiomyocyte Il11ra1 knockout VTI : Velocity time integral WT : Wild type