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Unpaired cysteine insertions favor transmembrane dimerization and induce ligand-independent constitutive cytokine receptor signaling.

Naturally occurring gain-of-function (GOF) mutants have been identified in patients for a variety of cytokine receptors. Although this constitutive activation ofcytokine receptors is strongly associated with malignant disorders, ligand-independent receptor activation is also a useful tool in synthetic biology e.g. to improve adoptive cellular therapies with genetically modified T-cells. Balanced Interleukin (IL-)7 signaling via a heterodimer of IL-7 receptor (IL-7Rα) and the common γ-chain (γc) controls T- and B-cell development and expansion, whereas uncontrolled IL-7 signaling can drive acute lymphoid leukemia (ALL) development. The ALL-driver mutation PPCL in the transmembrane domain of IL-7Rα is a mutational insertion of the four amino acids proline-proline-cysteine-leucine and leads to ligand-independent receptor dimerization and constitutive activation. We showed here in the cytokine-dependent pre-B-cell line Ba/F3 that the PPCL-insertion in a synthetic version of the IL-7Rα induced γc-independent STAT5 and ERKphosphorylation and also proliferation of the cells and that booster-stimulation by arteficial ligands additionally generated non-canonical STAT3 phosphorylation via the synthetic IL-7Rα-PPCL-receptors. Transfer of theIL-7Rα transmembrane domain with the PPCL insertion intonatural and synthetic cytokine receptor chains of the IL-6, IL-12 and Interferon families also resulted in constitutive receptor signaling. In conclusion, our data suggested that the insertion of the mutated PPCL IL-7Rα transmembrane domain is an universal approach to generate ligand-independent, constitutively active cytokine receptors.

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Advances in preclinical TCR characterization: leveraging cell avidity to identify functional TCRs.

T-cell therapy has emerged as an effective approach for treating viral infections and cancers. However, a significant challenge is the selection of T-cell receptors (TCRs) that exhibit the desired functionality. Conventionally invitro techniques, such as peptide sensitivity measurements and cytotoxicity assays, provide valuable insights into TCR potency but are labor-intensive. In contrast, measuring ligand binding properties (z-Movi technology) could provide an accelerated processing while showing robust correlations with T-cell functions. In this study, we assessed whether cell avidity can predict functionality also in the context of TCR-engineered Tcells. To this end, we developed a flexible system for TCR re-expression by generating a Jurkat-derived Tcell clone lacking TCR and CD3 expression through CRISPR-Cas9-mediated TRBC knockout. The knockin of a transgenic TCR into the TRAC locus restored TCR/CD3 expression, allowing for CD3-based purification of TCR-engineered Tcells. Subsequently, we characterized these engineered cell lines by functional readouts, and assessment of binding properties through the z-Movi technology. Our findings revealed a strong correlation between the cell avidities and functional sensitivities of Jurkat TCR-T cells. Altogether, by integrating cell avidity measurements with our versatile Tcell engineering platform, we established an accelerated system for enhancing the invitro selection of clinically relevant TCRs.

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Integrated machine learning and multimodal data fusion for patho-phenotypic feature recognition in iPSC models of dilated cardiomyopathy.

Integration of multiple data sources presents a challenge for accurate prediction of molecular patho-phenotypic features in automated analysis of data from human model systems. Here, we applied a machine learning-based data integration to distinguish patho-phenotypic features at the subcellular level for dilated cardiomyopathy (DCM). We employed a human induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) model of a DCM mutation in the sarcomere protein troponin T (TnT), TnT-R141W, compared to isogenic healthy (WT) control iPSC-CMs. We established a multimodal data fusion (MDF)-based analysis to integrate source datasets for Ca2+ transients, force measurements, and contractility recordings. Data were acquired for three additional layer types, single cells, cell monolayers, and 3D spheroid iPSC-CM models. For data analysis, numerical conversion as well as fusion of data from Ca2+ transients, force measurements, and contractility recordings, a non-negative blind deconvolution (NNBD)-based method was applied. Using an XGBoost algorithm, we found a high prediction accuracy for fused single cell, monolayer, and 3D spheroid iPSC-CM models (≥92±0.08 %), as well as for fused Ca2+ transient, beating force, and contractility models (>96±0.04 %). Integrating MDF and XGBoost provides a highly effective analysis tool for prediction of patho-phenotypic features in complex human disease models such as DCM iPSC-CMs.

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Apolipoprotein E-containing lipoproteins and their extracellular interactions with LRP1 affect LPS-induced inflammation.

The linkage between low-density lipoprotein receptor-related protein (LRP)1-mediated metabolism of apolipoprotein (apo) E-containing lipoproteins (apoE-LP) and the lipopolysaccharide (LPS)-induced inflammatory response contributes to the pathogenesis of sepsis; however, the underlying mechanisms are unclear. Therefore, in this study, the effects of apoE-LP and their constituents on the mRNA expression of interleukin (IL)-6 and LRP1 were evaluated using a culture system of human fibroblasts supplemented with LPS and apoE-containing emulsion particles (apoE-EP). The affinity of apoE-LP for LPS was examined using the interaction between fluorescence-labeled LPS and serum lipoprotein fractions. LPS-induced inflammation significantly upregulated the mRNA expression of IL-6 andLRP1. This upregulation was markedly suppressed by pre-incubation of LPS with apoE-EP or its constituents (apoE or EP). The suppressive effect of apoE-EP on IL-6 upregulation was attenuated in the presence of lactoferrin, an inhibitor of LRP1. The prepared apoE-EP and serum triglyceride-rich lipoproteins showed significant affinity for LPS. However, these affinities appeared to be lower than expected based on the extent to which IL-6 upregulation was suppressed by pre-incubation of LPS with apoE-EP. Overall, these results indicate that LPS-induced inflammation may be regulated by1) the LPS-neutralizing effect of apoE-LP, 2) anti-inflammatory effect of apoE, and 3) LRP1-mediated metabolic pathways.

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