Biology subjects

Herbert, C.

Publications and source records attributed to Herbert, C..

9 recordsLinked to original sources

bioRxiv2025

Riluzole as a Dual-Targeted Radiosensitizer for Osteosarcoma: Targeting Tumor Cells and Angiogenic Vasculature to Enhance Single High Dose Radiotherapy Efficacy

Osteosarcoma is a highly aggressive bone malignancy primarily affecting children and young adults. It presents significant treatment challenges due to its inherent resistance to conventional fractionated radiotherapy (CFRT). Single high dose radiation therapy (SDRT) has promise for the treatment of radioresistant sarcomas, especially those characterized with extensive vascularity. However, its clinical application is severely constrained by toxicity to adjacent critical tissues. Radiosensitizers can enhance tumor cell susceptibility to radiation-induced DNA damage, improving therapeutic efficacy and potentially reducing collateral toxicity. Monotherapies targeting tumor vasculature alone in solid tumors have shown limited success as radiosensitizers in clinical settings. This highlights the importance of compounds that can simultaneously target both tumor cells and its associated microvasculature to maximize the therapeutic outcome to SDRT. Riluzole, the FDA-approved drug for Amyotrophic Lateral Sclerosis, is currently under investigation as a therapeutic agent for osteosarcoma. Riluzole acts to inhibit glutamate release, reduce glutathione levels in cancer cells, and mitigate tumor angiogenesis, positioning it as a potent radiosensitizing agent for the treatment of osteosarcoma. We hypothesize that Riluzole enhances osteosarcoma radiosensitivity to SDRT by simultaneously targeting intrinsic tumor radioresistance and pro-angiogenic signaling. Our findings demonstrate that Riluzole radiosensitizes osteosarcoma cells in vitro by reducing clonogenic survival and enhancing apoptosis. Mechanistically, Riluzole potentiates irradiation-induced reactive oxygen species (ROS) production, induces G2/M phase cell cycle arrest, inhibits DNA repair, and thereby amplifies radiation-induced DNA damage. Additionally, Riluzole suppresses radiation-induced Vascular Endothelial growth factor A (VEGFA) expression indicating its ability to overcome endothelial cell mediated radioresistance. Collectively, these results establish Riluzole as a promising radiosensitizer for osteosarcoma, with the potential to improve SDRT efficacy by overcoming both tumor-intrinsic and microvasculature-mediated radioresistance. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=102 SRC="FIGDIR/small/681036v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@1839ca2org.highwire.dtl.DTLVardef@1a05dcaorg.highwire.dtl.DTLVardef@16da8cborg.highwire.dtl.DTLVardef@64ce1d_HPS_FORMAT_FIGEXP M_FIG C_FIG This schematic illustrates the proposed mechanism by which Riluzole enhances SDRT efficacy in osteosarcoma by targeting both tumor cells and VEGFA-mediated pro-survival signaling in endothelial cells. Riluzole increases radiation-induced ROS levels, induces G2/M cell cycle arrest, and inhibits DNA repair in osteosarcoma cells, thereby overcoming intrinsic tumor radioresistance. It also suppresses tumor cell VEGFA expression, which may contribute to reduced pro-survival signaling in the angiogenic endothelial cells within the tumor microenvironment. Together, these effects sensitize osteosarcoma tumors to SDRT, improving therapeutic outcomes (Illustration created using BioRender (BioRender.com, 2025)).

cancer biology↗

bioRxiv2025

Gene-Corrected Basal Cells Restore CFTR In Vitro; Transplants Regenerate Epithelium in a Preclinical Sinus Model

BackgroundCystic fibrosis (CF) is caused by mutations in the CFTR gene, leading to epithelial dysfunction and progressive lung disease. Although CFTR modulators have transformed care, [~]10% of people with CF remain without effective therapy. Durable, mutation-agnostic approaches are urgently needed. MethodWe used a lentiviral (LV) vector to deliver wild-type CFTR to airway basal cells derived from 13 paediatric CF participants with a range of genotypes. Transduced cells were assessed for transgene expression, epithelial differentiation, and CFTR function using air-liquid interface (ALI) cultures. Separately, to evaluate regenerative capacity in vivo, LVGFP-transduced rabbit airway basal cells were transplanted into the denuded nasal septum of healthy New Zealand white rabbits using a biocompatible scaffold. ResultsTransduced basal cells retained multilineage differentiation capacity, forming well-organized, pseudostratified epithelium with intact barrier function and ciliary activity. CFTR channel activity was restored to levels comparable to or exceeding those achieved with elexacaftor/tezacaftor/ivacaftor (ETI), including in individuals with nonsense mutations. Combined CFTR transduction plus ETI treatment showed additive benefit. In vivo, transplanted rabbit basal cells engrafted and differentiated to regenerate a mucociliary epithelium, with improved nasal potential difference and mucociliary clearance compared to scaffold-only controls. ConclusionOur study demonstrates that LV-mediated CFTR gene addition restores CFTR function in vitro across genotypes and supports epithelial regeneration in a clinically relevant animal airway model. This two-part platform offers a scalable path toward cell therapies for all people with CF and may have broader applications in upper airway epithelial repair.

cell biology↗

bioRxiv2025

A survey of dietary effects on tRNA abundance and modifications

Transfer RNAs (tRNAs) play a central role in protein translation and are increasingly recognized as dynamic regulators of gene expression. Both physiological and environmental signals can modulate tRNA abundance and chemical modifications, yet the impact of dietary cues on the tRNA landscape remains poorly understood. Here, we investigated the effects of two distinct dietary interventions--low-protein and high-fat diets--on tRNA abundance and modification profiles across multiple mouse tissues. We conducted a comprehensive analysis of tRNA abundance and modification changes in response to these nutritional challenges using RNA mass spectrometry and Ordered Two-Template Relay sequencing (OTTR-seq), a modified-base-sensitive tRNA sequencing method. Our results reveal both shared and tissue-specific alterations in abundance and modifications of specific nuclear and mitochondrial genome-encoded tRNAs in response to dietary conditions at isotype, isoacceptor, and isodecoder levels. As many of the tissue-specific or diet-responsive tRNA modifications have been previously reported to affect decoding efficiency or translational fidelity, these results have implications for understanding translational adaptation in response to dietary conditions.

genomics↗

bioRxiv2025

A microbiome-derived transfer RNA modification underlies behavioral optimums and predator avoidance in mosquito larvae

The gut microbiome is a rich source of nutrients that are critical to the development and biology of eukaryotes. Transfer RNAs (tRNAs) are essential components of protein synthesis, and some chemical modifications to tRNA rely on the availability of microbiome-derived nutrients. In eukaryotes, the micronutrient queuosine (Q) is salvaged from the microbiome or diet and then incorporated into eukaryotic tRNA to influence the speed and efficiency of protein synthesis. Here, we examine the role of microbiome-derived Q in mosquito larval development and behavior. When mosquito larvae are grown with a microbiome incapable of synthesizing Q, there is a significant impact on tyrosine levels and processes, which correlate with defects in behavior and cuticle formation. Due to defects in movement and behavioral responses, Q-deficient larvae demonstrate impaired predator evasion, leading to higher instances of capture by predaceous beetle larvae. The broad effects of Q-deficiency in mosquito larvae highlight the importance of microbiome-derived nutrients for eukaryotic physiology and behavior.

physiology↗

bioRxiv2024

Structural basis for aminoacylation of cellular modified tRNALys3 by human lysyl-tRNA synthetase

The average eukaryotic tRNA contains 13 posttranscriptional modifications; however, their functional impact is largely unknown. Our understanding of the complex tRNA aminoacylation machinery in metazoans also remains limited. Herein, using a series of high-resolution cryo-electron microscopy (cryo-EM) structures, we provide the mechanistic basis for recognition and aminoacylation of fully-modified cellular tRNALys3 by human lysyl-tRNA synthetase (h-LysRS). The tRNALys3 anticodon loop modifications S34 (mcm5s2U) and R37 (ms2t6A) play an integral role in recognition by h-LysRS. Modifications in the T-, variable-, and D-loops of tRNALys3 are critical for ordering the metazoan-specific N-terminal domain of LysRS. The two catalytic steps of tRNALys3 aminoacylation are structurally ordered; docking of the 3'-CCA end in the active site cannot proceed until the lysyl-adenylate intermediate is formed and the pyrophosphate byproduct is released. Association of the h-LysRS-tRNALys3 complex with a multi-tRNA synthetase complex-derived peptide shifts the equilibrium towards the 3'-CCA end docked conformation and allosterically enhances h-LysRS catalytic efficiency. The insights presented here have broad implications for understanding the role of tRNA modifications in protein synthesis, the human aminoacylation machinery, and the growing catalog of metabolic and neurological diseases linked to it.

biochemistry↗

bioRxiv2024

TRMT1L-catalyzed m22G27 on tyrosine tRNA is required for efficient mRNA translation and cell survival under oxidative stress.

tRNA modifications are critical for several aspects of their functions, including decoding, folding, and stability. Using a multifaceted approach encompassing eCLIP-seq and Nanopore tRNA-seq, we show that the human tRNA methyltransferase TRMT1L interacts with component of the Rix1 ribosome biogenesis complex and binds to the 28S rRNA, as well as to a subset of tRNAs. Mechanistically, we demonstrate that TRMT1L is responsible for catalyzing m22G solely at position 27 of tRNA-Tyr-GUA. Surprisingly, TRMT1L depletion also impaired the deposition of acp3U and dihydrouridine on tRNA-Tyr-GUA, Cys-GCA, and Ala-CGC. TRMT1L knockout cells have a marked decrease in tRNA-Tyr-GUA levels, coinciding with a reduction in global translation rates and hypersensitivity to oxidative stress. Our results establish TRMT1L as the elusive methyltransferase catalyzing the m22G27 modification on tRNA Tyr, resolving a long-standing gap of knowledge and highlighting its potential role in a tRNA modification circuit crucial for translation regulation and stress response.

molecular biology↗

bioRxiv2023

Tyrosine transfer RNA levels and modifications during blood-feeding and vitellogenesis in the mosquito, Aedes aegypti

Mosquitoes such as Aedes aegypti must consume a blood meal for the nutrients necessary for egg production. Several transcriptome and proteome changes occur post blood meal that likely corresponds with codon usage alterations. Transfer RNA (tRNA) is the adapter molecule that reads messenger RNA (mRNA) codons to add the appropriate amino acid during protein synthesis. Chemical modifications to tRNA enhance codons decoding, improving the accuracy and efficiency of protein synthesis. Here, we examined tRNA modifications and transcripts associated with the blood meal and subsequent periods of vitellogenesis in A. aegypti. More specifically, we assessed tRNA transcript abundance and modification levels in the fat body at critical times post blood-feeding. Based on a combination of alternative codon usage and identification of particular modifications, we identified that increased transcription of tyrosine tRNAs is likely critical during the synthesis of egg yolk proteins in the fat body following a blood meal. Altogether, changes in both the abundance and modification of tRNA are essential factors in the process of vitellogenin production after blood-feeding in mosquitoes.

biochemistry↗

bioRxiv2021

Microenvironmental correlates of immune checkpoint inhibitor response in human melanoma brain metastases revealed by T cell receptor and single-cell RNA sequencing

Melanoma-derived brain metastases (MBM) represent an unmet clinical need due to central nervous system (CNS) progression as a frequent, end-stage site of disease. Immune checkpoint inhibition (ICI) represents a clinical opportunity against MBM; however, the MBM tumor microenvironment (TME) has not been fully elucidated in the context of ICI. To dissect unique MBM-TME elements and correlates of MBM-ICI response, we collected 32 fresh MBM and performed single cell RNA sequencing of the MBM-TME and T cell receptor clonotyping on T cells from MBM and matched blood and extracranial lesions. We observed myeloid phenotypic heterogeneity, most notably multiple distinct neutrophil states including an IL-8 expressing population that correlated with malignant cell epithelial-to-mesenchymal transition. Additionally, we observe significant relationships between intracranial T cell phenotypes and the distribution of T cell clonotypes intracranially and peripherally. We found that the phenotype, clonotype, and overall number of MBM-infiltrating T cells were associated with response to ICI, suggesting that ICI-responsive MBMs interact with peripheral blood in a manner similar to extracranial lesions. These data demonstrate unique features of the MBM-TME, which may represent potential targets to improve clinical outcomes for patients with MBM.

cancer biology↗

bioRxiv2021

Abundances of transfer RNA modifications and transcriptional levels for tRNA-modifying enzymes are sex-specific in mosquitoes

As carriers of multiple human diseases, understanding the mechanisms behind mosquito reproduction may have implications for remediation strategies. Transfer RNA (tRNA) acts as the adapter molecule of amino acids and are key components in protein synthesis and a critical factor in the function of tRNAs is chemical modifications. Here, we provide an assessment of tRNA modifications between sexes for three mosquito species and examine correlated transcript levels underlying key proteins involved in tRNA modification. Thirty-three tRNA modifications were detected among mosquito species and most of these modifications are higher in females compared to males. Analysis of previous male and female RNAseq datasets indicated a similar increase in tRNA modifying enzymes in females, supporting our observed female enrichment of tRNA modifications. Tissues-specific expressional studies revealed high transcript levels for tRNA modifying enzymes in the ovaries for Aedes aegypti, but not male reproductive tissues. These studies suggest that tRNA modifications may be critical to reproduction in mosquitoes, representing a potential novel target for control.

biochemistry↗