Biology subjects

Brzezinski, C.

Publications and source records attributed to Brzezinski, C..

3 recordsLinked to original sources

bioRxiv2025

Rational redesign of antigen binding domain improves in vivo efficacy of CD22-CAR T cells

Chimeric antigen receptor (CAR) T cells targeted to CD19 are an effective therapy for B-lineage malignancies. However, about half of patients relapse and this therapeutic, often with antigen-negative disease, warranting the targeting of other antigens. CD22 represents another promising target, with highly restricted but ubiquitous expression across the B-lineage. However, despite promising preclinical work by several groups with CD22-targeted CAR T cells targeting of this antigen in the clinic has proven difficult, with many patients relapsing with CD22Lo leukemia, contrasting to complete loss of CD19 expression post CD19-CAR. While prior work has demonstrated that a CAR with so-called "tonic" antigen-independent signaling properties has proven to be highly efficacious, tonic signaling has been shown be detrimental to long-term T cell function. Here, we demonstrate a balance between binding affinity and antigen-independent tonic signaling (as determined by length of flexible linker) in determining CAR function. We show that maximal CAR function in the settings CD22Lo and WT leukemia is maintained by boosting binding affinity without shortening flexible linker to induce tonic signaling, establishing rational modification of antigen binding domain as an important approach for modulating the function of cellular therapeutics. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=179 HEIGHT=200 SRC="FIGDIR/small/643183v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1d543e3org.highwire.dtl.DTLVardef@5bf226org.highwire.dtl.DTLVardef@76cd2forg.highwire.dtl.DTLVardef@198fd37_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2023

Developmental Characterization of Neuronal Migration Anomalies and Axon Proliferation in mTOR pathway-associated Malformations of Cortical Development

Drug-resistant epilepsy (DRE) is a prevalent problem in children that can lead to abnormal development and various psychiatric comorbidities. Malformations of cortical development (MCD) include focal cortical dysplasia, tuberous sclerosis complex and hemimegalencephaly, which are the most common pathologies among children who undergo surgical resection for treatment of DRE. These disorders share many histopathological features, including dyslamination of the cerebral cortex and enlarged neuronal somata. Recently, genetic mutations in the mammalian target of rapamycin (mTOR) signaling cascade have been shown to underpin most MCDs. Rodent models, including the RhebCA model, recapitulate histologic and physiologic aspects of human DRE. However, there have been few studies characterizing the developmental time point of the histological changes seen in MCDs. In this study, we use in utero electroporation to upregulate the Rheb protein (directly upstream of mTOR) in a focal area of the neocortex. We demonstrate that mTOR dysregulation leads to focal dyslamination and increased neuronal size that is histologically similar to MCD, which correlates to spontaneous recurrent seizures. We used immunohistochemistry to investigate neuronal lamination at several time points during development between E18 and P21 and show early differences in lamination that persisted through development. Furthermore, the increased axonal length associated with mTOR upregulation occurs early in development. Our study provides a time frame for the initial development of abnormal neuronal migration and cellular growth that occurs in MCDs, and our data supports that these anatomical changes may contribute to the formation of epileptic networks.

neuroscience↗

bioRxiv2022

Characterizing the diversity of L2/3 human neocortical neurons in epilepsy

In the current study, we performed whole-cell current clamp recordings from human cortical neurons in layer 2/3 of the human neocortex in order to characterize the diversity of L2/3 human neocortical neurons in epileptic foci with various etiologies in order to begin to elucidate the underlying mechanisms of hyperexcitability which are still mostly unknown. We differentiated neuronal subtypes based on their firing patterns and AHP kinetics or epilepsy subtype (malformation of cortical development (MCD) vs. other (non-MCD)). We found that L2/3 pyramidal neurons have diverse firing properties and action potential kinetics, with some neurons looking remarkably similar to LTS interneurons. We also saw that L2/3 pyramidal neurons could be split into those with fast AHPs and those without, medium AHPs (mAHPs). Based on these parameters, we were unable to significantly differentiate neurons based on firing properties indicating that AHP component kinetics alone do not dictate L2/3 pyramidal neuron firing in human epileptic cortical slices. We also report significant differences in intrinsic properties between MCD and non-MCD and control L2/3 pyramidal neurons and are the first to characterize that wash on of the proconvulsant drug, 4-aminopyridine (4-AP), leads to increased AP duration, less firing rate (FR) accommodation, and slowed down AHPs. Overall, the present study is the first to characterize the large variability of L2/3 human neocortical pyramidal neurons, to compare between L2/3 pyramidal neurons within the epileptic foci between MCD and non-MCD cases, to use control tissue from tumor patients without incidence of seizure, and to determine the influence of 4-AP on L2/3 pyramidal neuron intrinsic properties.

neuroscience↗