Early detection of myocardial abnormalities or other ischemic heart diseases is critical for effective treatment. Here, we aimed to engineer a cell-based system to sense cardiac troponin I (cTnI), an Show more
Early detection of myocardial abnormalities or other ischemic heart diseases is critical for effective treatment. Here, we aimed to engineer a cell-based system to sense cardiac troponin I (cTnI), an early marker of acute myocardial infarction (AMI), and respond by releasing a thrombolytic agent. To detect cTnI, we engineered a chimeric troponin receptor (TropR) that contains extracellular single-chain variable fragments (scFvs) and signals via intracellular domains of interleukin 6 receptor subunit beta (IL6RB), epidermal growth factor receptor (EGFR), fibroblast growth factor receptor 1 (FGFR1), fibroblast growth factor receptor 2b (FGFR2b) or vascular endothelial growth factor receptor 2 (VEGFR2) that are associated with cardioprotective signaling. cTnI-dependent TropR functionality was confirmed in human embryonic kidney (HEK)-derived cell lines as well as iPSC-derived cardiomyocytes, and enabled rapid, reversible, tunable control of gene expression via synthetic-signaling-specific promoters. We then constructed monoclonal cell lines for cTnI-induced secretion of the thrombolytic protein tenecteplase (TNK), together with an off-switch triggered by FDA-approved doxycycline. We selected a clone, designated CardioProtect, whose sensitivity was optimized to detect human AMI-relevant cTnI levels. To validate thrombolytic efficacy, we established an ex vivo blood culture system and show that alginate-microencapsulated CardioProtect cells triggered complete lysis of fibrin clots in a strict cTnI-inducible, doxycycline-repressible manner. This closed-loop strategy serves as a proof-of-concept for using cell therapy in the early detection and treatment of AMI. Show less
Recently, we have shown that after partial hepatectomy (PHx), an increased hepatic blood flow initiates liver growth in mice by vasodilation and mechanically-triggered release of angiocrine signals. H Show more
Recently, we have shown that after partial hepatectomy (PHx), an increased hepatic blood flow initiates liver growth in mice by vasodilation and mechanically-triggered release of angiocrine signals. Here, we use mass spectrometry to identify a mechanically-induced angiocrine signal in human hepatic endothelial cells, that is, myeloid-derived growth factor (MYDGF). We show that it induces proliferation and promotes survival of primary human hepatocytes derived from different donors in two-dimensional cell culture, via activation of mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3). MYDGF also enhances proliferation of human hepatocytes in three-dimensional organoids. In vivo, genetic deletion of MYDGF decreases hepatocyte proliferation in the regenerating mouse liver after PHx; conversely, adeno-associated viral delivery of MYDGF increases hepatocyte proliferation and MAPK signaling after PHx. We conclude that MYDGF represents a mechanically-induced angiocrine signal and that it triggers growth of, and provides protection to, primary mouse and human hepatocytes. Show less
Cytokines control immune related events and are critically involved in a plethora of patho-physiological processes including autoimmunity and cancer development. In rare cases, single nucleotide polym Show more
Cytokines control immune related events and are critically involved in a plethora of patho-physiological processes including autoimmunity and cancer development. In rare cases, single nucleotide polymorphisms (SNPs) or single nucleotide variations (SNVs) in cytokine receptors eventually cause detrimental ligand-independent, constitutive activation of signal transduction. Most SNPs have, however, no or only marginal influences on gene expression, protein stability, localization and function and thereby only slightly affecting pathogenesis probability. The SNP database (dbSNP) is an archive for a broad collection of polymorphisms in which SNPs are categorized and marked with a locus accession number "reference SNP" (rs). Here, we engineered an algorithm to directly align dbSNP information to DNA and protein sequence information to clearly illustrate a genetic SNP landscape exemplified for all tall cytokine receptors of the IL-6/IL-12 family, including IL-23R, IL-12Rβ1, IL-12Rβ2, gp130, LIFR, OSMR and WSX-1. This information was complemented by a comprehensive literature summary and structural insights of relevant disease-causing SNPs in cytokine/cytokine receptor interfaces. In summary, we present a general strategy with potential to apply to other cytokine receptor networks. Show less