Project description:Epitranscriptomic modifications on RNA play critical roles in stability, processing, and function, partly by influencing interactions with RNA-binding proteins and receptors. The diverse role(s) of post-transcriptional RNA modifications on cell-free small non-coding RNAs (sRNA) remain poorly understood, particularly in disease contexts. Although HDL confer many beneficial properties to health, HDL particles lose these features during atherosclerotic cardiovascular disease (ASCVD). As HDL transport sRNA fragments from classes of RNA known to harbor extensive modifications, we predicted that changes to regulatory modifications on HDL-sRNAs may contribute to HDL functionality changes in ASCVD. To assess HDL-RNA modification levels in ASCVD, total RNA were isolated from HDL of healthy subjects (CAC=0) and those with advanced atherosclerosis, as determined by coronary artery calcium (CAC) scores >21 Agatston units. HDL-RNA were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and AlkB-facilitated RNA (de)Methylation Sequencing (ARM-seq). LC-MS/MS revealed elevated levels of modified nucleosides in HDL-sRNAs from ASCVD subjects, while ARM-seq detected an enrichment of m1A-modified sRNAs-derived from parent tRNAs (tDR), particularly tDR-ArgACG-1. To assess the impact of disease HDL on immune cells, primary macrophages were treated with HDL isolated from ASCVD (CAC+) and control subjects, and results showed that ASCVD-HDL directly induced expression of genes associated with immune signaling and cell adhesion, including TMEM123, a transmembrane protein linked to immune cell migration, adhesion, and cytoskeletal organization. In addition, recombinant HDL particles loaded with m1A-tDR-ArgACG-1 were found to significantly increase TMEM123 expression in treated primary macrophages. Together, these findings propose a model in which HDL-delivered m1A-HDL-tDRs directly stimulate immune signaling, macrophage activation, and pro-inflammatory sub-phenotypes within the atherosclerotic lesion. This study highlights HDL-associated RNA modifications as previously unrecognized contributors to immune modulation, with direct implications for targeting modified HDL-tDRs as a new approach to therapy for ASCVD.

Project description:Background: Resistance to trastuzumab remains a common challenge to HER-2 positive breast cancer. Up until now, the underlying mechanism of trastuzumab resistance is still unclear. tRNA-derived small non-coding RNAs (tDRs), a new class of small non-coding RNA (sncRNAs), have been observed to play an important role in cancer progression. However, the relationship between tDRs and trastuzumab resistance is still unknown. Methods: We detected the levels of tDRs expression in normal breast epithelial cell lines, trastuzumab-sensitive and -resistant breast cancer cell lines using high-throughput sequencing. qRT-PCR was conducted to validate the differentially expressed tDRs in serums from trastuzumab-sensitive and -resistant patients. A receiver operating characteristic (ROC) curve analysis was performed to evaluate the power of specific tDRs. Progression-free survival (PFS) was analyzed using Cox-regression. Furthermore, Gene Ontology (GO) and pathway analyses indicated the potential mechanism underlying tDR-mediated trastuzumab resistance. Results: Our sequence results showed that tDRs were differentially expressed in the HBL-100, SKBR3, and JIMT-1 cell lines. tDR-1960 and tDR-1969 were found significantly upregulated in trastuzumab-resistant patients compared to sensitive individuals, and the ROC analysis showed that tDR-1960 and tDR-1969 were correlated with trastuzumab resistance. In a multivariate analysis, higher levels of tDR-1960 and tDR-1969 expression were associated with signiﬁcantly shorter PFS in patients with metastatic HER-2 positive breast cancer. Additionally, the GO analysis indicated that tDR-1960 and tDR-1969 were mainly involved in the cellular response to drug, which may partially explain the molecular mechanism underlying trastuzumab resistance in HER-2 positive breast cancer. Conclusion: we comprehensively analyzed tDRs in trastuzumab-sensitive and -resistant breast cancer. Our results suggest that tDR-1960 and tDR-1969 play important roles in trastuzumab resistance. Patients with high levels of tDR-1960 and tDR-1969 expression benefitted less from trastuzumab-based therapy than those that express lower-levels of these tDRs. tDR-1960 and tDR-1969 may be potential biomarkers and intervention targets in the clinical treatment of trastuzumab-resistant breast cancer.

Project description:Transfer RNAs (tRNAs) and their derived small RNAs (tDRs) vary across mammalian tissues, but the . We applied Ordered Two-Template Relay sequencing (OTTR-seq) to profile small RNAs in 19 tissues from adult mice, quantifying mature tRNAs and tDRs at isodecoder resolution and inferring select base‑modification signatures from reverse‑transcriptase misincorporations. We observe tissue‑biased expression of many isodecoders and identify tDRs with greater tissue specificity than their parent tRNAs. Modification‑associated mismatch profiles are largely consistent across tissues, with notable isodecoder‑specific differences at canonical sites (e.g., A34→I, G37→m1G/wybutosine, C47d→m3C). Because RT‑based signatures do not capture all modifications without chemical pretreatments, our modification inferences represent a subset of the tRNA epitranscriptome. These data provide an isodecoder‑resolved reference for tissue‑biased tRNA and tDR regulation in mice and a framework for exploring disease‑associated remodeling of the tRNA pool. Recent studies have begun to illustrate that transfer RNA (tRNA) expression, processing, and modification can vary among different mammalian tissues and cell types. The full scope of these differences and the regulatory mechanisms that modulate production of a wide variety of tRNAs and tDRs (tRNA-derived small RNAs) across tissues, cell types, and changing cellular conditions is poorly understood. Dysregulation of these transcripts has increasingly been implicated as a critical factor in disease progression; thus, a deeper understanding of the homeostatic variance across somatic tissues is vital. Here, we systematically profile the relative changes in abundance and key sites of base modification within tRNAs, tDRs, and other small RNAs using a powerful small RNA sequencing method, Ordered Two-Template Relay sequencing (OTTR-seq), across a panel of 19 mouse tissues. By analyzing a diverse range of healthy tissues, we can better recognize tissue-biased regulation of tRNAs and identify tDRs that exhibit significantly greater tissue specificity than their corresponding source tRNAs. Furthermore, we leveraged reverse transcriptase-associated base misincorporations to construct an isodecoder-specific map of select nucleotide modifications across all mouse tRNAs. Differentially modified isodecoders can alter their translation functionality, stability, and basis for production of unique tDR profiles. This dataset provides the most comprehensive view to date of the dynamic relationships between tRNAs, their modifications, and tDRs in a mammalian model, offering an important knowledgebase for understanding tissue-specific regulation and the role of these molecules in disease.

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Post-transcriptional modifications on tRNA fragments confer functional changes to high-density lipoproteins in atherosclerosis

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