Biology subjects

Brazda, P.

Publications and source records attributed to Brazda, P..

7 recordsLinked to original sources

bioRxiv2026

Platform-Imprinted Transcriptional and Clonal Remodeling of αβ and γδT Cells After Allogeneic Transplantation

Immune reconstitution after allogeneic hematopoietic stem cell transplantation is influenced by graft-composition and viral reactivation, but the combined long-term impact on {beta} and {gamma}{delta}T cells remains unclear. We analyzed a cohort of 213 patients receiving either {beta}T cell-depleted grafts (n=146; graft engineering that removes donor {beta}T cells) or T cell-replete grafts (n=67; containing donor T cells). Longitudinal immune phenotyping was integrated with bulk and single-cell TCR repertoire and transcriptomic profiling. CMV reactivation was associated with expansion of CD8+ {beta}T cells across both transplant types and with numerical dominance of V{delta}2- {gamma}{delta}T cells specifically in {beta}T cell-depleted recipients. V{delta}2- {gamma}{delta}T cells underwent early polyclonal expansion followed by repertoire focusing, independent of CMV, whereas {beta}T cells remained clonally restricted. Reduced early V{delta}2+ {gamma}{delta}TCR diversity was associated with EBV reactivation. Single-cell and TCR tracking analyses revealed long-term persistence of donor-derived V{delta}2+ {gamma}{delta}TCRs, whereas V{delta}1+ {gamma}{delta} and {beta}T cell repertoires were predominantly rebuilt de novo. Despite de novo rebuilding, {beta}TCR repertoire diversity diverged by platform at one year: {beta}T cell-depleted recipients exhibited marked (hyper)expansion of {beta}TCR clonotypes and lower diversity than T cell-replete recipients, indicating a durable imprint of graft engineering on {beta}TCR-clonality. Transcriptomic profiling showed that post-transplant T cells predominantly adopted effector programs, with platform-dependent polarization toward cytotoxic signatures in {beta}T cell-depleted recipients and toward AREG-associated tissue-repair signatures in T cell-replete recipients, consistent with wound-healing functions. In conclusion, transplantation platforms imprint durable clonal and transcriptional remodeling of {beta} and {gamma}{delta}T cells, while viral reactivation primarily amplifies expansion without fundamentally reshaping repertoire architecture. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/704768v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@88f136org.highwire.dtl.DTLVardef@944f13org.highwire.dtl.DTLVardef@d3835corg.highwire.dtl.DTLVardef@5548ef_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

Functional γδT-omics pipeline reveals compartmentalization of Vδ1⁺ T cell migration, tumor-reactivity, and clonality in human colorectal cancer

{gamma}{delta}T cells play a pivotal role in cancer immune surveillance, yet the current knowledge of their function across the compartments in solid tumors is meager. To address this gap, we developed a comprehensive {gamma}{delta}T-omics platform that integrates functional screening, biomimetic migration assays, {gamma}{delta}TCR repertoire analysis, and transcriptomic profiling. Using matched samples from 31 patients with microsatellite-stable colorectal cancer (CRC), we analyzed {gamma}{delta}T cells from peripheral blood (PBLs{gamma}{delta}), adjacent colon (LPLs{gamma}{delta}), primary tumors (pTILs{gamma}{delta}), and liver metastases (mTILs{gamma}{delta}). This approach uncovered striking compartmentalization of {gamma}{delta}T cell phenotypes, clonality, and function. Tumor-reactive, clonally expanded V{delta}1 {gamma}{delta}T cells were enriched in primary tumors and shared transcriptional and functional features with lamina propria lymphocytes (LPLs). In contrast, V{delta}1 {gamma}{delta}T cells from liver metastases lacked tumor reactivity, exhibited distinct {gamma}{delta}TCR repertoires, and expressed transcriptional signatures associated with TGF-{beta}-mediated suppression and cellular quiescence, suggesting they are shaped by tissue-specific environmental cues. CXCL16 secretion by tumor cells initiated V{delta}1 LPLs{gamma}{delta} migration, which was further amplified by {gamma}{delta}TCR-mediated CCL5 induction from pTILs{gamma}{delta}, leading to CCR5 downregulation and subsequent entrapment of pTILs{gamma}{delta} within the tumor microenvironment. Accordingly, our clinical data from an independent second cohort of 69 patients showed that infiltration by pTILs{gamma}{delta}, but not mTILs{gamma}{delta}, is associated with a protective effect against CRC progression. In summary, our study offers a compartment-resolved perspective on {gamma}{delta}T cell behavior in CRC, revealing key trafficking and functional mechanisms, and enabling the identification of novel tumor-reactive {gamma}{delta}TCRs and migratory cues to inform immunotherapeutic strategies for both primary and metastatic CRC. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=179 SRC="FIGDIR/small/671055v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@ff3bborg.highwire.dtl.DTLVardef@14a7e1forg.highwire.dtl.DTLVardef@19e4de4org.highwire.dtl.DTLVardef@bc600_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

Podocalyxin and ciliary neurotrophic factor receptor are novel components of the surfaceome of chondrogenic cells

BackgroundOsteoarthritis is a degenerative joint disease characterized by progressive loss of articular cartilage and limited capacity for intrinsic repair. A major barrier to developing effective regenerative strategies is the incomplete understanding of the molecular mechanisms regulating chondrogenesis and cartilage maintenance. Cell surface proteins are key mediators of extracellular communication, adhesion, and signaling, yet the chondrogenic surfaceome remains incompletely mapped, with prior studies focusing primarily on mature or cytokine-activated chondrocytes. The aim of this study was to provide a temporal profile of the surfaceome during in vitro chondrogenic differentiation and to identify novel membrane proteins with potential roles in cartilage biology. MethodsWe applied a sialoglycoprotein-targeted glycocapture strategy to selectively enrich plasma membrane proteins from chick embryonic limb bud-derived micromass cultures undergoing chondrogenesis. Enriched samples underwent high-resolution shotgun proteomic analysis, and differentially expressed candidates were validated by western blotting, immunocytochemistry, and transient gene silencing. Functional effects on extracellular matrix gene regulation were assessed by quantitative RT-PCR and matrix histochemistry. ResultsThis approach generated the first temporal surfaceome map of chondrogenic progenitors. Among identified candidates, two proteins not previously linked to chondrogenesis, podocalyxin (PODXL) and ciliary neurotrophic factor receptor (CNTFR), were detected at the plasma membrane and confirmed at the protein and transcript levels. Both proteins exhibited time-dependent downregulation during differentiation. Targeted knockdown revealed differential regulation of the fibrocartilage marker COL1A1 expression, indicating non-redundant roles in cell-matrix signaling and survival pathways. Single-cell transcriptomic meta-analysis confirmed expression of both proteins in discrete human articular chondrocyte subpopulations. ConclusionsThis study expands the molecular framework of chondrogenesis, identifying PODXL and CNTFR as novel, temporally regulated surfaceome components with distinct roles in extracellular matrix signaling. These findings complement prior proteomic analyses of cytokine-activated mature articular chondrocytes and suggest new candidates for developmental cartilage biomarkers and therapeutic targets for osteoarthritis. Our results provide a resource for future cross-species surfaceome studies and highlight key pathways for further investigation into cartilage lineage specification and matrix adaptation. Plain English SummaryOsteoarthritis is the most common joint disease worldwide, causing pain, stiffness, and reduced mobility as the smooth cartilage that covers the ends of bones gradually breaks down. Cartilage has a very limited ability to heal itself, and there are currently no treatments that can stop or reverse the disease. Scientists are working on new ways to repair or replace damaged cartilage, but to do this effectively, they need to understand the molecular "language" that cartilage-forming cells use to develop and maintain healthy tissue. In this study, we examined the set of proteins that are present on the surface of cartilage-forming cells, known as the "surfaceome." These surface proteins play important roles in how cells connect to their surroundings, receive signals, and work together to build the cartilage matrix. Using a method to selectively capture and analyze these proteins, we discovered two that had never been linked to cartilage development: podocalyxin and ciliary neurotrophic factor receptor. We found that these two proteins may have opposite effects on cartilage quality. Because they can be detected on the outside of cells, they could be developed into markers for early osteoarthritis detection or as targets for new therapies. Our findings open the door to new strategies for diagnosing and treating joint disease by focusing on cell-surface communication.

cell biology↗

bioRxiv2024

Sensitivity to Vγ9Vδ2TCR T cells is imprinted after single mutations during early oncogenesis

V{gamma}9V{delta}2T cells have the unique ability to recognize a broad range of malignant transformed cells. The tumor targeting event involving BTN2A1 and BTN3A1 dimers on the tumor cell surface is critical, leading to full activation of the TCR. Although the molecular mechanisms governing TCR engagement and T cell activation are well-characterized, the role of V{gamma}9V{delta}2 T cells in cancer immune surveillance remains to be fully elucidated, particularly the mechanisms that enable these cells to discriminate between healthy and malignant cells at an early stage of malignant transformation. We employed two independent, genetically engineered step-wise mutagenesis models of human colorectal and breast cancer that mimic the transformation steps leading to tumor formation. We demonstrate that various single oncogenic mutations introduced into healthy organoids or cells, are sufficient to upregulate surface expressed BTN2A1 and enable V{gamma}9V{delta}2 TCR binding to tumor cells. However, full activation of T cells through a V{gamma}9V{delta}2TCR required additional subsequent phosphorylation of juxtamembrane (JTM) amino acids of BTN3A1, leading to the activating heterodimerization of BTN2A1 and 3A1. Using a protein interactome mapping pipeline, we identified PHLDB2, SYNJ2 and CARMIL1 as key players in controlling these delicate dual surface dynamics of BTN2A1 and 3A1 during early transformation. This mode of action allowed V{gamma}9V{delta}2TCR T cells to control tumors in vitro and in vivo, emphasizing the crucial role of these molecules from early mutagenesis, to advanced cancer stages, and highlighting the therapeutic potential of a V{gamma}9V{delta}2TCR.

cancer biology↗

bioRxiv2022

Extensive patient-to-patient single nuclei transcriptome heterogeneity in pheochromocytomas and paragangliomas

Pheochromocytomas (PC) and paragangliomas (PG) are rare neuroendocrine tumors of varied genetic makeup, associated with high cardiovascular morbidity and a variable risk of malignancy. The source of the transcriptional heterogeneity of the disease and the underlying biological processes determining the outcome in PCPG remains largely unclear. We focused on PCPG tumors with germline SDHB and RET mutations, representing distinct prognostic groups with worse or better prognoses, respectively. We applied single-nuclei RNA sequencing (snRNA-seq) on tissue samples from 11 patients and found high patient-to-patient transcriptome heterogeneity of the neuroendocrine tumor cells. The tumor microenvironment also showed heterogeneous profiles mainly contributed by macrophages of the immune cell clusters and Schwann cells of the stroma. Performing non-negative matrix factorization we identified common transcriptional programs active in RET and SDHB as well as distinct modules? including neuronal development, hormone synthesis and secretion, and DNA replication. Comparison of the SDHB and RET transcriptomes with that of developmental stages of adrenal gland formation suggests different developmental stages at which PC and PG tumors appear to be arrested.

cancer biology↗

bioRxiv2022

Longitudinal single-cell transcriptomics reveals distinct patterns of recurrence in acute myeloid leukemia

The heterogeneity and evolution of AML blasts can render therapeutic interventions ineffective in a yet poorly understood patient-specific manner. To gain insight into the clonal heterogeneity of diagnosis (Dx) and relapse (Re) pairs, we employed whole-exome sequencing and single-cell RNA-seq to longitudinally profile two t(8;21) (AML1-ETO = RUNX1-RUNX1T1), and four FLT3-ITD AML cases. The single cell RNA data underpinned the tumor heterogeneity amongst patient blasts. The Dx-Re transcriptomes of high risk FLT3-ITD pairs formed a continuum from extensively changed in the absence of significantly mutational changes in AML-associated genes to rather similar Dx-Re pair of an intermediate risk FLT3-ITD. In one high risk FLT3-ITD pair, a pathway switched from an AP-1 regulated network in Dx to mTOR signaling in Re. The distinct AML1-ETO pairs comprise clusters that share genes related to hematopoietic stem cell maintenance and cell migration suggesting that the Re leukemic stem cell-like (LSC-like) cells probably evolved from the Dx LSC-like cells. In summary, our study revealed a continuum from drastic transcriptional changes to extensive similarities between respective Dx-Re pairs that are poorly explained by the well-established model of clonal evolution. Our results suggest alternative and currently unappreciated and unexplored mechanisms leading to therapeutic resistance and AML recurrence.

cancer biology↗

bioRxiv2021

Behavioral-transcriptomic landscape of engineered T cells targeting human cancer organoids

Cellular immunotherapies are rapidly gaining clinical importance, yet predictive platforms for modeling their mode of action are lacking. Here, we developed a dynamic immuno-organoid 3D imaging-transcriptomics platform; BEHAV3D, to unravel the behavioral and underlying molecular mechanisms of solid tumor targeting. Applied to an emerging cancer metabolome-sensing immunotherapy: TEGs, we first demonstrate targeting of multiple breast cancer subtypes. Live-tracking of over 120,000 TEGs revealed a diverse behavioral landscape and identified a super engager cluster with serial killing capability. Inference of single-cell behavior with transcriptomics identified the gene signature of super engager killer TEGs, which contained 27 genes with no previously described T cell function. Furthermore, guided by a dynamic type 1 interferon (IFN-I) signaling module induced by high TEG-sensitive organoids, we show that IFN-I can prime resistant organoids for TEG-mediated killing. Thus, BEHAV3D characterizes behavioral-phenotypic heterogeneity of cellular immunotherapies and holds promise for improving solid tumor-targeting in a patient-specific manner.

cancer biology↗