Biology subjects

Olive, M. E.

Publications and source records attributed to Olive, M. E..

6 recordsLinked to original sources

bioRxiv2025

Congenital CMV infection drives oligoclonal expansion of cytotoxic γδ T cells from early fetal progenitors

Gamma delta T cells ({gamma}{delta} T cells) emerge early during human gestation and are uniquely equipped to protect the fetus and infant following in utero infection with viruses such as cytomegalovirus (CMV). Previous research showed that fetal {gamma}{delta} T cells in early gestation are transcriptionally pre-programmed for effector functions in the thymus. Infants with congenital CMV infection (cCMV) exhibit expansions of {gamma}{delta} T cells with CMV-reactive TCRs; however, the functional and transcriptional programming of these innate-like effector cells has not been characterized. Here, we analyzed cord blood mononuclear cells from cCMV+ and uninfected neonates in Uganda using flow cytometry and single-cell RNA and TCR sequencing. We find that {gamma}{delta} T cells in cCMV+ neonates are more differentiated, activated, cytotoxic, and proliferative. TCR repertoires of cCMV+ infants exhibit oligoclonal expansions with an enrichment of {gamma}{delta}TCRs that possess shorter CDR3 lengths and fewer N additions, which suggest they arise from early fetal progenitor cells. These expanded {gamma}{delta} T cell clonotypes in cCMV+ infants are more frequently public and exhibit cytotoxic transcriptional programming. These findings demonstrate that cCMV infection drives an oligoclonal expansion of highly cytotoxic effector {gamma}{delta} T cells with fetal-like TCR features, underscoring their specialized roles in early-life immunity.

immunology↗

bioRxiv2025

Inhibitory NK receptors regulate the γδ T cell response to malaria

Gamma delta ({gamma}{delta}) T cells are important mediators of the immune response to childhood malaria infection. Human V{gamma}9+V{delta}2+ T cells possess intrinsic, HLA-independent responsiveness to Plasmodium falciparum phosphoantigens produced in the blood stage of malaria infection. Engagement of the {gamma}{delta} T cell receptor (TCR) by phosphoantigen-bound butyrophilin molecules results in V{gamma}9+V{delta}2+ T cell expansion, pro-inflammatory cytokine production, and release of cytotoxic granules that mediate parasite killing. Repeated malaria infection, however, leads to a reduction in circulating V{gamma}9+V{delta}2+ T cells and upregulation of immunomodulatory molecules, including NK receptors, that correlates with less severe symptoms upon infection. We explore phenotypic and functional differences of {gamma}{delta} T cells in Ugandan children with high versus low malaria exposure, utilizing high-parameter spectral flow cytometry analysis of PBMCs. We observed significant differences in expression of inhibitory NK receptors - KIR2DL1, KIR2DL2/3, KIR3DL1, LILRB1, and NKG2A - on {gamma}{delta} T cell subsets, with V{gamma}9+V{delta}2+ T cells exhibiting a divergent mechanism of control compared to other subsets. We found that NKG2A and KIR3DL1 expression associated with potent V{gamma}9+V{delta}2+ T cell responses to TCR- and Fc receptor (FcR)-mediated stimulation while KIR2DL1, KIR2DL2/3 and LILRB1 associated with reduced degranulation and cytokine production. These results identify a new role for inhibitory NK receptors expressed on {gamma}{delta} T cells, exerting a finely tuned balance of activating and inhibitory signals to regulate the response to malaria-related antigens. AUTHOR SUMMARYMalaria remains one of the deadliest infectious diseases, disproportionately affecting young children in sub-Saharan Africa who succumb to sequelae of Plasmodium falciparum infection. However, children living in highly endemic areas experience repeated malaria infection and develop naturally acquired-but not sterilizing-immunity which leads to an asymptomatic reinfection pattern. The immune factors that determine the balance of inflammatory and tolerogenic functions seen in non-sterilizing malaria immunity are yet to be fully understood. Here, we focus on the phenotypic and functional differences in one cell type between children with a history of low versus high malaria exposure. We identified a group of inhibitory surface receptors that improved the antimalarial function of this cell, and another group that worsened their function. Our study clarifies the immune landscape in highly malaria-exposed individuals and illuminates one potential system of regulating the cellular response to repeat infection.

immunology↗

bioRxiv2023

Proteome-wide base editor screens to assess phosphorylation site functionality in high-throughput

Signaling pathways that drive gene expression are typically depicted as having a dozen or so landmark phosphorylation and transcriptional events. In reality, thousands of dynamic post-translational modifications (PTMs) orchestrate nearly every cellular function, and we lack technologies to find causal links between these vast biochemical pathways and genetic circuits at scale. Here, we describe "signaling-to-transcription network" mapping through the development of PTM-centric base editing coupled to phenotypic screens, directed by temporally-resolved phosphoproteomics. Using T cell activation as a model, we observe hundreds of unstudied phosphorylation sites that modulate NFAT transcriptional activity. We identify the phosphorylation-mediated nuclear localization of the phosphatase PHLPP1 which promotes NFAT but inhibits NF{kappa}B activity. We also find that specific phosphosite mutants can alter gene expression in subtle yet distinct patterns, demonstrating the potential for fine-tuning transcriptional responses. Overall, base editor screening of PTM sites provides a powerful platform to dissect PTM function within signaling pathways.

systems biology↗

bioRxiv2022

Arginine-dependent hypusination of the eukaryotic translation initiation factor (eIF)5A drives erythroid lineage differentiation

Metabolic programs contribute to hematopoietic stem and progenitor cell (HSPC) fate but it is not known whether the metabolic regulation of protein synthesis controls HSPC differentiation. We discovered that SLC7A1/CAT1-dependent arginine uptake and its catabolism to spermidine control the erythroid specification of HSPCs via activation of eukaryotic translation initiation factor 5A (eIF5A). eIF5A activity is dependent on the metabolism of spermidine to hypusine and inhibiting hypusine synthesis abrogates erythropoiesis and diverts EPO-stimulated HSPCs to a myeloid fate. Proteomic profiling reveals mitochondrial translation to be a critical target of hypusinated eIF5A and induction of mitochondrial function partially rescues erythropoiesis in the absence of hypusine. Within the hypusine network, ribosomal proteins are highly enriched and we identify defective eIF5A hypusination in erythroid pathologies caused by abnormal ribosome biogenesis. Thus, eIF5A-dependent protein synthesis is critical in the branching of erythro-myeloid differentiation and attenuated eIF5A activity characterizes ribosomal protein-linked disorders of ineffective erythropoiesis.

physiology↗

bioRxiv2021

MONTE enables serial immunopeptidome, ubiquitylome, proteome, phosphoproteome, acetylome analyses of sample-limited tissues

Serial multiomic analyses of proteome, phosphoproteome and acetylome provides functional insights into disease pathology and drug effects while conserving precious human material. To date, ubiquitylome and HLA peptidome analyses have required separate samples for parallel processing each using distinct protocols. Here we present MONTE, a highly-sensitive multi-omic native tissue enrichment workflow that enables serial, deepscale analysis of HLA-I and HLA-II immunopeptidome, ubiquitylome, proteome, phosphoproteome and acetylome from the same tissue samples. We demonstrate the capabilities of MONTE in a proof-of-concept study of primary patient lung adenocarcinoma(LUAD) tumors. Depth of coverage and quantitative precision at each of the omes is not compromised by serialization, and the addition of HLA immunopeptidomics enables identification of putative immunotherapeutic targets such as cancer/testis antigens and neoantigens. MONTE can provide insights into disease-specific changes in antigen presentation, protein expression, protein degradation, cell signaling, cross-talk and epigenetic pathways involved in disease pathology and treatment.

cancer biology↗

bioRxiv2021

Automating UbiFast for High-throughput and Multiplexed Ubiquitin Enrichment

Robust methods for deep-scale enrichment and site-specific identification of ubiquitylation sites is necessary for characterizing the myriad roles of protein ubiquitylation. To this end we previously developed UbiFast, a sensitive method for highly multiplexed ubiquitylation profiling where K-{varepsilon}-GG peptides are enriched with anti-K-{varepsilon}-GG antibody and labeled on-antibody with isobaric labeling reagents for sample multiplexing. Here, we present robotic automation of the UbiFast method using a magnetic bead-conjugated K-{varepsilon}-GG antibody (mK-{varepsilon}-GG) and a magnetic particle processor. We report the identification of [~]20,000 ubiquitylation sites from a TMT10-plex with 500 g input per sample processed in [~]2 hours. Automation of the UbiFast method greatly increased the number of identified and quantified ubiquitylation sites, improved reproducibility and significantly reduced processing time. The workflow enables processing of up to 96 samples in a single day making it suitable to study ubiquitylation in large sample sets. Here we demonstrate the applicability of this method to profile small amounts of tissue using breast cancer patient-derived xenograft (PDX) tissue samples.

biochemistry↗