Biology subjects

Park, J. E.

Publications and source records attributed to Park, J. E..

16 recordsLinked to original sources

bioRxiv2026

PSEN1 mutant marmoset fibroblasts mimic multi-omic signatures of Alzheimer's disease

INTRODUCTIONThe slow, age-related development of Alzheimers disease (AD) and inaccessibility of early-stage brain tissue necessitates model studies to understand its origins and progression. Non-human primate models can provide a platform for linking molecular changes to translatable phenotypes. Here, we assess fibroblast lines derived from marmosets with engineered variants in the PSEN1 gene. METHODSFibroblast cultures were obtained from 10 animals and assayed using a NanoString AD gene expression panel and label-free proteomics. We compared mutant expression changes to human AD signatures in human iPSC-derived neurons and postmortem brains to assess disease relevance. RESULTSGene products involved in amyloid-beta interaction and regulation were differentially expressed, providing evidence for the functional relevance of the engineered fibroblasts. Both gene and protein expression changes in the undifferentiated fibroblasts correlated with human iPSCs from AD donors reprogrammed into neuronal lineages, as well as postmortem brains derived from case-control cohorts. Altered expression profiles were noted based on marmoset donor sex and mutation status, highlighting underlying sex-specific biology relevant to Alzheimers disease. DISCUSSIONThese findings demonstrate that disease-relevant pathways and processes are altered in fibroblasts from mutant marmosets, emphasize the complementarity of transcriptomic and proteomic profiling in AD, and provide a roadmap for more advanced molecular studies of AD in aging marmosets and marmoset-derived cell models.

genomics↗

bioRxiv2026

A Complete Genome for the Common Marmoset

The common marmoset is a New World monkey (NWM) commonly used as a model organism to investigate questions in primate evolution and human disease, including Alzheimers and other neurodegenerative diseases, as well as neuropsychiatric disorders. Here we present the first telomere-to-telomere (T2T) reference genome for the common marmoset, adding over 88 Mb of sequence and resolving challenging genomic regions. An additional near-T2T assembly from a second unrelated individual yields a total of four high-quality haplotypes for analysis. The improved contiguity and accuracy of these assemblies enable unprecedented insights into complex and rapidly evolving genomic regions such as centromeres, sex chromosomes, ribosomal DNA (rDNA) structure, and the major histocompatibility complex (MHC). We fully resolved all marmoset centromeres, uncovering dimeric alpha satellites with chromosomal specificity and stratified inactive layers documenting ancestral centromere turnover. We assembled six acrocentric autosomes with gene-poor, satellite-rich short arms and provide evidence that most of them can harbor rDNA and all of them share large pseudo-homologous regions (PHRs). The Y chromosome, but not the X chromosome, carries active rDNA and PHRs, and the rDNA copy number is sexually dimorphic. Chromosomes that share PHRs also share closely related centromeric satellite DNA, supporting a model of ongoing recombinational exchange between heterologous chromosomes facilitated by rDNA. We discovered multiple novel, marmoset-specific MHC genes that are predicted to protect against pathogens encountered in its environment. Leveraging this complete reference, we further identified over 500 transcribed genes with transcript models or expansions specific to the marmoset lineage. Together with additional long-read marmoset assemblies, these genomes were used to construct a marmoset pangenome, providing a robust reference framework for short-read mapping across diverse individuals. This resource will improve the utility of the common marmoset as a biomedical model organism and fill key gaps in our understanding of primate evolution.

genomics↗

bioRxiv2024

Key Regulatory Elements of the TGFbeta-LRRC15 Axis Predict Disease Progression and Immunotherapy Resistance Across Cancer Types

Transforming growth factor-beta (TGF{beta}) has dual roles in cancer, initially suppressing tumors but later promoting metastasis and immune evasion. Efforts to inhibit TGF{beta} have been largely unsuccessful due to significant toxicity and indiscriminate immunosuppression. Leucine-rich repeat-containing protein 15 (LRRC15) is a TGF{beta}-regulated antigen expressed by mesenchymal-derived cancer cells and cancer-associated fibroblasts (CAFs). In preclinical studies, ablation of TGF{beta}-driven LRRC15+ CAFs increased tumor infiltration of CD8+ T cells. However, the underlying pathobiological mechanisms prompting TGF{beta}s upregulation of LRRC15 expression are unclear. Using an integrated approach combining functional compound screening with single-cell RNA sequencing, we reveal key genomic features regulating TGF{beta}s ability to increase LRRC15 expression on cancer cells. Construction of gene regulatory networks converged our analyses on four key genes--MMP2, SPARC, TGF{beta}R2, and WNT5B--central to TGF{beta}-induced LRRC15 pathobiology. Validation of these genes in cell models and their use in predicting immunotherapy responses highlight their potential in refining immunotherapy strategies and personalizing co-treatment options.

pharmacology and toxicology↗

bioRxiv2024

Protein-protein interactions with G3BPs drive stress granule condensation and gene expression changes under cellular stress

Stress granules (SGs) are macromolecular assemblies that form under cellular stress. Formation of these condensates is driven by the condensation of RNA and RNA-binding proteins such as G3BPs. G3BPs condense into SGs following stress-induced translational arrest. Three G3BP paralogs (G3BP1, G3BP2A, and G3BP2B) have been identified in vertebrates. However, the contribution of different G3BP paralogs to stress granule formation and stress-induced gene expression changes is incompletely understood. Here, we identified key residues for G3BP condensation such as V11. This conserved amino acid is required for formation of the G3BP-Caprin-1 complex, hence promoting SG assembly. Total RNA sequencing and ribosome profiling revealed that disruption of G3BP condensation corresponds to changes in mRNA levels and ribosome engagement during the integrated stress response (ISR). Moreover, we found that G3BP2B preferentially condenses and promotes changes in mRNA expression under endoplasmic reticulum (ER) stress. Together, this work suggests that stress granule assembly promotes changes in gene expression under cellular stress, which is differentially regulated by G3BP paralogs.

cell biology↗

bioRxiv2024

Development of a LRRC15-Targeted Radio-Immunotheranostic Approach to Deplete Pro-tumorigenic Mechanisms and Immunotherapy Resistance

Leucine-rich repeat containing 15 (LRRC15) has emerged as an attractive biomarker and target for cancer therapy. We have developed a humanized monoclonal antibody (mAb), DUNP19, that specifically binds to a phylogenetically conserved LRRC15 epitope and is internalized by target-expressing cancer and stromal cells. In xenograft mouse models, Lutetium-177 labeled DUNP19 ([177Lu]-DUNP19) enables non-invasive imaging and precise radiotherapy to LRRC15-expressing cancer cells and murine cancer-associated fibroblasts (CAFs), halting tumor progression and prolonging survival with minimal toxicity. Transcriptomic analyses of [177Lu]-DUNP19-treated tumors reveal a loss of pro-tumorigenic mechanisms, including a transforming growth factor beta (TGF{beta})-driven and LRRC15+ signature associated with immunotherapy resistance. Together, these results demonstrate that radio-theranostic targeting of LRRC15 with DUNP19 is a compelling precision medicine platform for image-guided diagnosis, eradication, and reprogramming of LRRC15+ tumor tissue that drives immuno-resistance and aggressive disease. SIGNIFICANCEWe introduce a pioneering LRRC15-guided radio-theranostic approach integrating clinical imaging and radioimmunotherapy. Our strategy utilizes a mAb, DUNP19, to target LRRC15-expressing cancer cells and fibroblasts, demonstrating significant tumor reduction, prolonged survival, and reversal of TGF{beta}-driven treatment resistance. This approach offers a promising strategy for improving outcomes in aggressive cancers.

pharmacology and toxicology↗

bioRxiv2022

Complementary CRISPR screen highlights the contrasting role of membrane-bound and soluble ICAM-1 in regulating antigen specific tumor cell killing by cytotoxic T cells

Cytotoxic CD8+ T lymphocytes (CTLs) are key players of adaptive anti-tumor immunity based on their ability to specifically recognize and destroy tumor cells. Many cancer immunotherapies rely on unleashing CTL function. However, tumors can evade killing through strategies which are not yet fully elucidated. To provide deeper insight into tumor evasion mechanisms in an antigen-dependent manner, we established a human co-culture system composed of tumor and primary immune cells. Using this system, we systematically investigated intrinsic regulators of tumor resistance by conducting a complementary CRISPR screen approach. By harnessing CRISPR activation (CRISPRa) and CRISPR knockout (KO) technology in parallel, we investigated gene gain-of-function as well as loss-of-function across genes with annotated function. CRISPRa and CRISPR KO screens uncovered 186 and 704 hits respectively, with 60 gene hits overlapping between both. These data confirmed the role of interferon-{gamma} (IFN-{gamma}), tumor necrosis factor (TNF-) and autophagy pathways and uncovered new genes implicated in tumor resistance to killing. Notably, we discovered that ILKAP encoding the integrin-linked kinase-associated serine/threonine phosphatase 2C, a gene previously unknown to play a role in antigen specific CTL-mediated killing, mediate tumor resistance independently from regulating antigen presentation, IFN-{gamma} or TNF- responsiveness. Moreover, our work describes the contrasting role of soluble and membrane-bound ICAM-1 in regulating tumor cell killing. The deficiency of membrane-bound ICAM-1 (mICAM-1) or the overexpression of soluble ICAM-1 (sICAM-1) induced resistance to CTL killing, whereas PD-L1 overexpression had no impact. These results highlight the essential role of ICAM-1 at the immunological synapse between tumor and CTL and the antagonist function of sICAM-1.

cancer biology↗

bioRxiv2022

Assessing Functional Androgen Receptor Pathway Activity in Response to Radiotherapy Using hK2-targeted PET Imaging

External beam radiotherapy (EBRT) remains a common treatment for all stages of PCa, but DNA damage induced by EBRT upregulates androgen receptor (AR) pathway activity to promote therapeutic resistance. [89Zr]11B6-PET is a novel modality targeting prostate-specific protein human kallikrein 2 (hK2), which is a surrogate biomarker for AR activity. Here, we studied if [89Zr]11B6-PET can accurately assess EBRT-induced AR activity. PCa mouse models received EBRT (2-50 Gy) and treatment response was monitored by [89Zr]11B6-PET/CT. Radiotracer uptake and expression of AR and AR target genes was quantified in resected tissue. EBRT increased AR pathway activity in LNCaP-AR tumors. EBRT increased prostate-specific [89Zr]11B6 uptake and hK2 levels in PCa-bearing mice (Hi-Myc x Pb_KLK2) with no significant changes in uptake in healthy (Pb_KLK2) mice. Thus, [89Zr]11B6-PET specifically detects activation of AR pathway activity after EBRT in PCa. Further clinical evaluation of hK2-PET for monitoring EBRT is warranted.

cancer biology↗

bioRxiv2021

A merger between compatible but divergent genomes supports allopolyploidization in the Brassicaceae family

Hybridization and polyploidization are pivotal to plant evolution. Genetic crosses between distantly related species rarely occur in nature mainly due to reproductive barriers but how such hurdles can be overcome is largely unknown. xBrassicoraphanus is a fertile intergeneric allopolyploid synthesized between Brassica rapa and Raphanus sativus in the Brassicaceae family. Genomes of B. rapa and R. sativus are diverged enough to suppress synapsis formation between non-homologous progenitor chromosomes during meiosis, and we found that both genomes reside in the single nucleus of xBrassicoraphanus without genome loss or rearrangement. Expressions of syntenic orthologs identified in B. rapa and R. sativus were adjusted to a hybrid nuclear environment of xBrassicoraphanus, which necessitates reconfiguration of transcription network by rewiring cis-trans interactions. B. rapa coding sequences have a higher level of gene-body methylation than R. sativus, and such methylation asymmetry is maintained in xBrassicoraphanus. B. rapa-originated transposable elements were transcriptionally silenced in xBrassicoraphanus, rendered by gain of CHG methylation in trans via small RNAs derived from the same sequences of R. sativus subgenome. Our work proposes that not only transcription compatibility but also a certain extent of genome divergence supports hybrid genome stabilization, which may explain great diversification and expansion of angiosperms during evolution.

plant biology↗

bioRxiv2020

Increased isoDGR motifs in plasma fibronectin are associated with atherosclerosis through facilitation of vascular fibrosis

Abnormal matrix deposition on vessels and recruitment of inflammatory cells into the arterial wall are critical events in atherosclerotic plaque formation. Fibronectin protein is a key matrix component that exhibits high levels of deamidation in atherosclerotic plaques and blood plasma, but it is unclear how this structural change impacts on endothelial function or modifies interactions with recruited leukocytes. This study aimed to determine how deamidation-induced isoDGR motifs in fibronectin influence extracellular matrix accumulation on endothelial cells, and to investigate possible effects on integrin outside-in signalling in matrix-bound monocytes which are key mediators of human atherosclerosis. Blood plasma fibrinogen and fibronectin displayed marked accumulation of isoDGR motifs in ischemic heart disease (IHD) as determined by ELISA analysis of patients undergoing coronary artery bypass grafting compared with age-matched healthy controls. Biochemical and functional assays confirmed that isoDGR-containing fibronectin promoted activation of integrin {beta}1 in monocytes and facilitated protein deposition and fibrillogenesis on endothelial cell layers. In addition, isoDGR interactions with integrins on the monocyte cell surface triggered an ERK:AP-1 signalling cascade that induced potent secretion of chemotactic mediators (including CCL2, CCL4, IL-8, and TNF), that promoted further leukocyte recruitment to the assembling plaque. Fibronectin deamidation forms isoDGR motifs that increase binding to {beta}1 integrins on the surface of endothelial cells and monocytes. Subsequent activation of integrin outside-in signalling pathways elicits a range of potent cytokines and chemokines that drive additional leukocyte recruitment to the developing atherosclerotic matrix and likely constitutes a key early event in progression to IHD.

biochemistry↗

bioRxiv2020

Precise and programmable C:G to G:C base editing in genomic DNA

Many genetic diseases are caused by single-nucleotide polymorphisms (SNPs). Base editors can correct SNPs at single-nucleotide resolution, but until recently, only allowed for C:G to T:A and A:T to G:C transition edits, addressing four out of twelve possible DNA base substitutions. Here we developed a novel class of C:G to G:C Base Editors (CGBEs) to create single-base genomic transversions in human cells. Our CGBEs consist of a nickase CRISPR-Cas9 (nCas9) fused to a cytosine deaminase and base excision repair (BER) proteins. Characterization of >30 CGBE candidates and 27 guide RNAs (gRNAs) revealed that CGBEs predominantly perform C:G to G:C editing (up to 90% purity), with rAPOBEC-nCas9-rXRCC1 being the most efficient (mean C:G to G:C edits at 15% and up to 37%). CGBEs target cytosine in WCW, ACC or GCT sequence contexts and within a precise two-nucleotide window of the target protospacer. We further targeted genes linked to dyslipidemia, hypertrophic cardiomyopathy, and deafness, showing the therapeutic potential of CGBE in interrogating and correcting human genetic diseases.

synthetic biology↗

bioRxiv2020

TuNR: Orthogonal Control of Mean and Variability of Endogenous Genes in a Human Cell Line

Stochastic fluctuations at the transcriptional level contribute to isogenic cell-to-cell heterogeneity in mammalian cell populations. However, we still have no clear understanding of the repercussions of this heterogeneity, given the lack of tools to independently control mean expression and variability of a gene. Here, we engineered a synthetic circuit to independently modulate mean expression and heterogeneity of transgenes and endogenous human genes. The circuit, a Tunable Noise Rheostat (TuNR), consists of a transcriptional cascade of two inducible transcriptional activators, where the output mean and variance can be modulated by two orthogonal small molecule inputs. In this fashion, different combinations of the inputs can achieve the same mean but with different population variability. With TuNR, we achieve low basal expression, over 1000-fold expression of a transgene product, and up to 7-fold induction of the endogenous gene NGFR. Importantly, for the same mean expression level, we are able to establish varying degrees of heterogeneity in expression within an isogenic population, thereby decoupling gene expression noise from its mean. TuNR is therefore a modular tool that can be used in mammalian cells to enable direct interrogation of the implications of cell-to-cell variability.Competing Interest StatementThe authors have declared no competing interest.View Full Text

synthetic biology↗

bioRxiv2020

Cancer-specific loss of TERT activation sensitizes glioblastoma to DNA damage

Most glioblastomas (GBMs) achieve cellular immortality by acquiring a mutation in the telomerase reverse transcriptase (TERT) promoter. TERT promoter mutations create a binding site for a GA binding protein (GABP) transcription factor complex, whose assembly at the promoter is associated with TERT reactivation and telomere maintenance. Here, we demonstrate increased binding of a specific GABPB1L isoform-containing complex to the mutant TERT promoter. Furthermore, we find that TERT promoter mutant GBM cells, unlike wild-type cells, exhibit a critical near-term dependence on GABPB1L for proliferation, both in cell culture and post-tumor establishment in vivo. Upregulation of the protein paralogue GABPB2, which is normally expressed at very low levels, can rescue this dependence. More importantly, when combined with frontline temozolomide (TMZ) chemotherapy, inducible GABPB1L knockdown and the associated TERT reduction led to an impaired DNA damage response that resulted in profoundly reduced growth of intracranial GBM tumors. Together, these findings provide new insights into the mechanism of cancer-specific TERT regulation, uncover rapid effects of GABPB1L-mediated TERT suppression in GBM maintenance, and establish GABPB1L inhibition in combination with chemotherapy as a novel therapeutic strategy for TERT promoter mutant GBM.

cancer biology↗

bioRxiv2019

ERO1α promotes hypoxic tumour progression and is associated with poor prognosis in pancreatic cancer

Pancreatic cancer is a leading cause of mortality worldwide due to difficulty detecting early-stage disease and our poor understanding of the mediators that drive the progression of hypoxic solid tumours. We, therefore, used a heavy isotope pulse/trace proteomic approach to determine how hypoxia alters pancreatic tumour expression of proteins that confer treatment resistance, promote metastasis, and suppress host immunity. Using this method, we identified that hypoxia stress stimulates pancreatic cancer cells to rapidly translate proteins that enhance metastasis (NOTCH2, NCS1, CD151, NUSAP1), treatment resistant (ABCB6), immune suppression (NFIL3,WDR4), angiogenesis (ANGPT4, ERO1, FOS), alter cell metabolic activity (HK2, ENO2), and mediate growth-promoting cytokine responses (CLK3, ANGPTL4). Database mining confirmed that elevated gene expression of these hypoxia-induced mediators is significantly associated with poor patient survival in various stages of pancreatic cancer. Among these proteins, the oxidoreductase enzyme ERO1 was highly sensitive to induction by hypoxia stress across a range of different pancreatic cancer cell lines and was associated with particularly poor prognosis in human patients. Consistent with these data, genetic deletion of ERO1 substantially reduced growth rates and colony formation in pancreatic cancer cells when assessed in a series of functional assays in vitro. Accordingly, when transferred into a mouse xenograft model, ERO1-deficient tumour cells exhibited severe growth restriction and negligible disease progression in vivo. Together, these data indicate that ERO1 is potential prognostic biomarker and novel drug target for pancreatic cancer therapy.

cancer biology↗

bioRxiv2019

Dynamics of murine brain protein synthesis in vivo identify the hippocampus, cortex and cerebellum as highly active metabolic sites

Identification of proteins that are synthesized de novo in response to specific microenvironmental cues is critical to understanding the molecular mechanisms that underpin key physiological processes and pathologies. Here we report that a brief period of pulsed SILAC diet (Stable Isotope Labelling by Amino acids in Cell culture) enables determination of biological functions corresponding to actively translating proteins in the mouse brain. Our data demonstrate that the hippocampus, cortex and cerebellum are highly active sites of protein synthesis, rapidly expressing key mediators of nutrient sensing and lipid metabolism, as well as critical regulators of synaptic function, axon guidance, and circadian entrainment. Together, these findings confirm that protein metabolic activity varies significantly between brain regions in vivo and indicate that pSILAC-based approaches can identify specific anatomical sites and biological pathways likely to be suitable for drug targeting in neurodegenerative disorders.\n\nAbbreviationsApoA1: Apolipoprotein A1, ApoA4: Apolipoprotein A4, ApoE: Apolipoprotein E, ApoJ/Clu: Apolipoprotein J/Clusterin, App: Amyloid-{beta} precursor/A4 protein: App, HDL: high density lipoprotein, Lrp1: Low density lipoprotein receptor-related protein 1, pSILAC: pulsed SILAC, pSIVOM: pulsed-SILAC in vivo labelling in mouse, SILAC: Stable Isotope Labelling by Amino acids in Cell culture)

neuroscience↗

bioRxiv2018

In silico Drug Repositioning of bortezomib to reverse metastatic effect of GALNT14 in lung cancer

Although many molecular targets for cancer therapy have been discovered, they often show poor druggability, which is a major obstacle to develop targeted drugs. As an alternative route to drug discovery, we adopted an in silico drug repositioning (in silico DR) approach based on large-scale gene expression signatures, with the goal of identifying inhibitors of lung cancer metastasis. Our analysis of clinicogenomic data identified GALNT14, an enzyme involved in O-linked N-acetyl galactosamine glycosylation, as a putative driver of lung cancer metastasis leading to poor survival. To overcome the poor druggability of GALNT14, we leveraged Connectivity Map approach, an in silico screening for drugs that are likely to revert the metastatic expression patterns. It leads to identification of bortezomib (BTZ) as a potent metastatic inhibitor, bypassing direct inhibition of poorly druggable target, GALNT14. The anti-metastatic effect of BTZ was verified in vitro and in vivo. Notably, both BTZ treatment and GALNT14 knockdown attenuated TGF{beta}-mediated gene expression and suppressed TGF{beta}-dependent metastatic genes, suggesting that BTZ acts by modulating TGF{beta} signalingTaken together, these results demonstrate that our in silico DR approach is a viable strategy to identify a candidate drug for undruggable targets, and to uncover its underlying mechanisms.

cancer biology↗

bioRxiv2017

Dynamic expression of tRNA-derived small RNAs define cellular states

Transfer RNA (tRNA)-derived small RNAs (tsRNAs) have recently emerged as important regulators of protein translation and shown to have diverse biological functions. However, the underlying cellular and molecular mechanisms of tsRNA function in the context of dynamic cell-state transitions remain unclear. Here we report the identification of a set of tsRNAs upregulated in differentiating mouse embryonic stem cells (mESCs). Mechanistic analyses revealed primary functions of tsRNAs in regulating polysome assembly and translation. Notably, interactome studies with differentially-enriched tsRNAs revealed a switch in associations with effector RNPs and target mRNAs in different cell-states. We also demonstrate that a specific pool of tsRNAs can interact with Igf2bp1, an RNA-binding protein, to influence the expression of the pluripotency-promoting factor-c-Myc, thereby providing evidence for tsRNAs in modulating stem cell-states in mESCs. Finally, tsRNA expression analyses in distinct, heterologous cell and tissue models of stem/transformed versus differentiated/normal states reveal that tsRNA-mediated regulation of protein translation may represent a global biological phenomenon associated with cell-state transitions.\n\nOne Sentence SummaryIdentification and functional characterization of tRNA-derived small RNAs (tsRNAs) in cell state switches.

molecular biology↗