Biology subjects

Zook, H. N.

Publications and source records attributed to Zook, H. N..

3 recordsLinked to original sources

bioRxiv2026

Distinct viability and oxygen-sensing responses to hypoxia and reoxygenation in pancreatic islets

Early graft hypoxia limits the efficiency and success of islet transplantation. Defining the relationships among oxygen availability, exposure duration, islet survival, and oxygen sensing is therefore critical, but these relationships remain incompletely understood. We examined adult primary rat islets under continuous exposure to 1%, 5%, or 18% O2 for 48 or 96 h and under reoxygenation conditions comprising 48 h at 1% O2 followed by 48 h at 18% O2. We assessed islet size-dependent viability, morphology, mass recovery, estimated viable mass, and targeted hypoxia-responsive gene-expression signatures. Overall, 6,699 individual islets were analyzed. At 1% O2, viability decreased significantly, with most loss occurring within the first 48 h (93.0% at 0 h, 70.8% at 48 h, and 65.0% at 96 h). Overall viability remained largely preserved at 5% and 18% O2 (92.8 and 95.0% at 96h, respectively), although larger islets showed vulnerability at 5% O2. Exposure to 1% O2 caused deformation, particularly in larger islets, and reduced estimated viable mass compared with 5% and 18% O2. Reoxygenation did not fully restore viability or estimated viable mass (76.0% at 96h). Gene-expression analyses revealed sustained hypoxia-responsive signatures at both 1% and 5% O2, distinct from those at 18% O2. Reoxygenation shifted gene-expression profiles toward a normoxia-like signature. These findings suggest divergent viability and oxygen-sensing responses to hypoxia and reoxygenation. The 5% O2 condition may represent a marginal oxygen environment that preserves short-term overall survival despite sustained molecular responses to hypoxia. These data inform the oxygen targets and timing of early graft oxygenation strategies.

cell biology↗

bioRxiv2026

Oxygen-permeable microwell plates for high-throughput spheroid culture

Oxygen (O2) transport is a major limitation in high-density cell culture, particularly as three-dimensional (3D) spheroids are increasingly used to better mimic in vivo tissue environments. Here, we developed a poly(4-methyl-1-pentene) (PMP)-based microwell platform, leveraging its lower molecular absorption and greater mechanical stability than the commonly used O2-permeable polydimethylsiloxane (PDMS), while retaining high O2 permeability. We measured O2 permeability in 50-m-thick PMP membranes and found approximately 200-fold greater O2 permeability than the conventional 1-mm polystyrene culture-plate material. PMP membrane-based microwell plates with 350-m-diameter wells maintained spatial separation of pre-formed hepatocyte spheroids while supplying O2 from the plate bottom, synergistically enhancing spheroid oxygenation. Compared with non-O2-permeable plates, the platform reduced localized hypoxia and hypoxia-associated cell injury while improving spheroid viability and growth. Collectively, PMP-based O2-permeable microwell plates provide a promising, scalable, high-throughput platform for spheroid culture with multiple applications in tissue engineering, drug screening and beyond.

bioengineering↗

bioRxiv2026

A long-term organotypic slice culture model of patient high-grade glioma preserving tumor heterogeneity and architecture, and specificity of CAR T cell targeting

ABSTRACT Background: High grade glioma (HGG), encompassing IDH-wildtype glioblastoma (CNS WHO grade 4), diffuse midline glioma (CNS WHO grade 4), oligodendroglioma (IDH-mutant and 1p/19q-codeleted) CNS WHO grade 3, together with IDH-mutant astrocytoma of CNS grade 3 and grade 4, represents the most lethal group of adult diffuse gliomas. Despite significant efforts, obtaining improvements in patient survival has been limited, in part, by difficulties in comprehensive ex vivo modeling of the complexities of HGG. Although organotypic slice cultures and other platforms have shown promise, existing models often fail to capture the intrinsic cellular heterogeneity, microenvironment, and architecture of HGG, restricting investigations into their fundamental biology as well as design of novel therapeutics. Methods: We developed a patient-derived HGG organotypic slice culture (GOSC) platform demonstrating long-term preservation of intrinsic tumor characteristics. Vibratome-sectioned slices were cultured in defined medium under conditions approximating those in situ: reduced oxygen (4%), low glucose (2.5 mM), and no added growth factors. The characteristics of GOSCs after 28 days in culture, including expression of immunotherapy targets, were compared to parental tumors using histological staining, immunofluorescence, multiplexed PhenoCycler (CODEX) imaging, bulk RNA-seq expression profiling, and CAR T cell killing assays. Results: GOSCs preserved the histopathology, cell heterogeneity, tumor microenvironment, and tissue architecture of their parental tumors throughout at least 28 days in culture. Importantly, GOSCs retained parental patterns of immunotherapy target expression, and CAR T cells co-cultured with GOSCs demonstrated target-specific killing consistent with parental tumors. Conclusions: This ex vivo GOSC platform offers long-term preservation of the cellular and structural properties of parental HGG tumors, thereby providing a robust tool for extended preclinical studies, and facilitating development and evaluation of advanced tumor-targeting strategies.

cancer biology↗