Biology subjects

Polansky, J.

Publications and source records attributed to Polansky, J..

3 recordsLinked to original sources

bioRxiv2025

Clinical development of gene edited tacrolimus-resistant Treg (FKBP12KO-Treg) to enable simultaneous immunosuppression and support of immune regulation

Background: Unwanted immune responses play a central role in the pathogenesis of solid organ allograft rejection. These are managed by life-long immunosuppression with considerable burden for the patient and society. Adoptive therapy with regulatory T-cells (Treg) is a promising approach to restore sustainable immune balance and avoid long-term adverse effects of immunosuppression. While Treg effectively inhibit activation of unwanted immune responses, they are less effective in controlling pre-existing/activated memory effector T-cells (Teff). Thus, co-administration of Treg with immunosuppressants is required to achieve a sustainable organ acceptance. Calcineurin inhibitors (CNI) are powerful in controlling de novo generated and preformed Teff. However, CNI also dampen Treg immunoregulatory function. Thus, we hypothesize improved results of adoptive Treg therapy in immunosuppressed patients applying tacrolimus-resistant Treg. Methods: While retaining CNI modulation of Teff with tacrolimus, we knocked-out FKBP12 in Treg (FKBP12KO-Treg) by gene-editing using ribonucleoprotein-based CRISPR/Cas9 technology to generate tacrolimus-resistant Treg and characterised them using flow cytometry, functional assays and in-depth phenotyping. Results: This detailed in vitro analysis showed FKBP12KO-Treg were comparable to non-gene edited Treg and impervious to tacrolimus while maintaining immunoregulatory function and sensitivity to alternative CNIs raising no safety concerns. Furthermore, we aligned our methodology to achieve GMP compliance laying the basis for a manufacturing license in preparation of a clinical trial. Conclusion: Based on the presented preclinical dataset implying safety and efficacy of FKBP12KO-Treg, we are now seeking to undertake a proof-of-concept clinical trial to evaluate the co-administrationof FKBP12KO-Treg and tacrolimus to enhance the management of living donor kidney transplant recipients.

immunology↗

bioRxiv2024

Fetal Liver-like Organoids Recapitulate Blood-Liver Niche Development and Multipotent Hematopoiesis from Human Pluripotent Stem Cells

The fetal liver is a hematopoietic organ, hosting a diverse and evolving progenitor population. While human liver organoids derived from pluripotent stem cells (PSCs) mimic aspects of embryonic and fetal development, they typically lack the complex hematopoietic niche and the interaction between hepatic and hematopoietic development. We describe the generation of human Fetal Liver-like Organoids (FLOs), that model human hepato-hematopoietic interactions previously characterized in mouse models. Developing FLOs first integrate a yolk sac-like hemogenic endothelium into hepatic endoderm and mesoderm specification. As the hepatic and hematopoietic lineages differentiate, the FLO culture model establishes an autonomous niche capable of driving subsequent progenitor differentiation without exogenous factors. Consistent with yolk sac-derived waves, hematopoietic progenitor cells (HPCs) within FLOs exhibit multipotency with a preference for myeloid lineage commitment, while retaining fetal B and T cell differentiation potential. We reconstruct in FLOs the embryonic monocyte-to-macrophage and granulocyte immune trajectories within the FLO microenvironment and assess their functional responses in the liver niche. In vivo, FLOs demonstrate a liver engraftment bias of hematopoietic cells, recapitulating a key phenomenon of human hematopoietic ontogeny. Our findings highlight the intrinsic capacity of liver organoids to support hematopoietic development, establishing FLOs as a platform for modeling and manipulating human blood-liver niche interactions during critical stages of development and disease.

developmental biology↗

bioRxiv2017

Progressive change in killer-like receptor and GPR56 expression defines cytokine production of human CD4+ T memory cells

Memory T cells mount an accelerated response upon re-challenge but are heterogeneous in phenotype and function. Traditionally memory T cells were classified into central memory, effector memory and terminally differentiated effector memory (TEMRA) cells based on expression of CCR7 and CD45RA. Functional heterogeneity even within these subsets demonstrated the need for more suitable markers. We applied bulk and single gene expression profiling of human CD4+ memory T cells and identified surface markers, KLRB1, KLRG1, GPR56 and KLRF1, allowing classification into \"low\", \"high\" or \"exhausted\" cytokine producers. In contrast to common understanding KLRG1 expression was not associated with exhaustion and highest production of multiple cytokines was observed in KLRB1+KLRG1+GPR56+ T cells. Only additional KLRF1 expression was associated with a decline in cytokine production. The superiority of KLRF1 to define exhausted cytokine producers compared to classical TEMRA identification was best exemplified for intrahepatic T cells in patients with inflammatory liver diseases.

immunology↗