Biology subjects

Geltink, R. I. K.

Publications and source records attributed to Geltink, R. I. K..

3 recordsLinked to original sources

bioRxiv2026

Versatile electroporation protocols enable reproducible CRISPR-RNP delivery across multiple primary mouse cells of the hematopoietic lineage

Genetic engineering of primary hematopoietic cells is essential for mechanistic immunology studies, however the development of cell-based therapies yet remains constrained by two major factors: the fragility of many primary lineages and challenges of viral delivery platforms that are costly, time-intensive, and biologically confounding. Here, we optimized scalable, non-viral CRISPR-Cas9 electroporation workflows using the ExPERT platform across three primary mouse hematopoietic cell types: OT-I CD8 T cells, bone marrow-derived macrophages (BMDMs), and hematopoietic stem cells (HSCs). In activated OT-I CD8 T cells, two electroporation programs supported high-efficiency mRNA and RNP delivery with minimal impact on cell viability or proliferative capacity, with subtle activation-state-dependent sensitivity at higher energy settings. Extending optimization to myeloid and stem cell lineages, we found that BMDMs maintained high viability following electroporation, and a high-performing electroporation program supported robust RNP delivery and efficient target gene knockout while preserving macrophage differentiation. In HSCs, the same program enabled consistent RNP delivery, sustained viability, and reproducible gene knockout. Together, these findings establish ExPERT electroporation as a robust, reproducible, and modular platform for non-viral genome editing across primary mouse hematopoietic lineages, lowering barriers to rapid genetic perturbation for both discovery and translational applications.

cell biology↗

bioRxiv2023

Inducing an oxidized redox-balance improves anti-tumor CD8+ T cell function

Cancer immunotherapy using antigen-specific CD8+ T cells depends on long-lasting anti-tumor function of the in vitro expanded T cells. T cell function is intricately linked to the activity of many metabolic pathways directly impacting the ability of CD8+ T cells to kill tumor cells. Metabolic conditioning in vitro better prepares CD8+ T cells for in vivo survival, tumor infiltration and tumor clearance. The mechanism underlying in vitro metabolic conditioning-induced augmented in vivo T cell function remains poorly understood. Here we show that metabolic conditioning of CD8+ effector T cells induces an oxidized cellular redox balance at least in part mediated by increased mitochondrial reactive oxygen species (ROS). This redox shift contributes to enhanced in vivo persistence and tumor clearance. In human tumour-infiltrating T cells, altering the redox balance ex-vivo reinvigorated pro-inflammatory cytokine production. Therefore, we believe that redox alterations present a targetable pathway to increase T cell-based anti-tumor immunotherapy efficacy.

immunology↗

bioRxiv2022

PTEN is required for human Treg suppression of costimulation

Regulatory T cell (Treg) therapy is under clinical investigation for the treatment of transplant rejection, autoimmune disease, and graft-versus-host disease. With the advent of genome editing, attention has turned to reinforcing Treg function for therapeutic benefit. A hallmark of Tregs is dampened activation of PI3K-AKT signalling, of which PTEN is a major negative regulator. Loss-of-function studies of PTEN, however, have not conclusively shown a requirement for PTEN in upholding Treg function and stability. Using CRISPR-based genome editing in human Tregs, we show that PTEN ablation does not cause a global defect in Treg function and stability; rather, it selectively blocks their ability to suppress antigen-presenting cells. PTEN-KO Tregs exhibit elevated glycolytic activity, upregulate FOXP3, maintain a Treg phenotype, and have no discernable defects in lineage stability. Functionally, PTEN is dispensable for human Treg-mediated inhibition of T cell activity in vitro and in vivo but is required for suppression of costimulatory molecule expression by antigen-presenting cells. These data are the first to define a role for a signalling pathway in controlling a subset of human Treg activity. Moreover, they point to the functional necessity of PTEN-regulated PI3K-AKT activity for optimal human Treg function.

immunology↗