Mitochondrial tRNA-derived fragments link mtDNA variation to metastatic burden [lung]
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE324706 | GEO | 2026/08/07
REPOSITORIES: GEO
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Project description:How mitochondrial DNA (mtDNA) polymorphisms influence complex phenotypes remains poorly understood. Using Mitochondrial-Nuclear eXchange (MNX) mice, we previously showed that mtDNA single nucleotide polymorphisms (SNP) modify metastasis, cardiovascular disease, and epigenetic marks independently of metabolic differences, suggesting a role for non-protein-coding loci. The only SNP correlating with these phenotypes resides in the gene encoding mitochondrial tRNA-Arginine (mt-tRNAArg (UCG), mt-TR). Here we identify and preliminarily characterize previously undescribed tRNA-derived fragments (tRF) generated from mt-TR. Northern blotting revealed distinct tRF that are differentially expressed between lung and liver and between sexes. Small RNA sequencing failed to capture these tRF unless samples were pre-treated to enzymatically remove non-canonical RNA termini and base methylation. Focusing on fragments with complete homology to mt-TR, the two most abundant tRF align uniquely to the mitochondrial genome and share conserved cleavage sites. Together, these findings uncover mitochondrial-derived tRF as a previously unrecognized small RNA metastasis modifiers and expand the functional output of the mitochondrial genome, supporting a model in which mtDNA-encoded tRF contribute to phenotype modification.
2026-08-07 | GSE324681 | GEO
Project description:In this study, we discovered cytosolic and mitochondrial fragments resulting from tRNA and mt-tRNA cleavage, which may act as new regulators of cellular and metabolic functions. We selected the mt-tRF-LeuTAA fragment for further investigation, as its level is altered in the islets diabetes-susceptible animal models, while being abundant in ß-cells. mt-tRF-LeuTAA fragment is derived from the cleavage of tRNA-LeuTAA encoded by the mitochondrial genome. We demonstrated that mt-tRF-LeuTAA acts as a key regulator of mitochondrial OXPHOS functions, mitochondrial membrane potential, the insulin secretory capacity of ß-cells, and the insulin sensitivity of myotube muscle cells. To gain a comprehensive understanding, we conducted transcriptomic and proteomic analyses on rat islets with silenced mt-tRF-LeuTAA for 72 hours. We transfected rat islet cells with an antisense oligonucleotides (antisense oligonucleotides to reduce mt-tRF-LeuTAA levels versus control oligos). These oligos specifically decreased the levels of the fragment (anti-tRF-LeuTAA) by more than 95% without affecting the host full-length tRNA mt-tRNA-LeuTAA. Inhibiting mt-tRF-LeuTAA led to significant differential expression of 4843 mRNA transcripts, cut-off adjusted P ≤ 0.05. To further investigate the cellular rearrangement associated with the inhibition of mt-tRF-LeuTAA, we conducted enrichment analysis using Gene Ontology Molecular Function terms on RNA-sequencing. At the transcriptomic level, we observed enrichment of pathways related to ion transport and various enzymatic activities, including mitochondrial oxidoreductase activity, when the mitochondrial fragment was repressed in rat islets.
2024-05-14 | GSE240395 | GEO
Project description:In this study, we discovered cytosolic and mitochondrial fragments resulting from tRNA and mt-tRNA cleavage, which may act as new regulators of cellular and metabolic functions. We selected the mt-tRF-LeuTAA fragment derived from a tRNA encoded by the mitochondrial genome for further investigation, as its level is reduced in the islets of diabetes-susceptible animal models, while being abundant in ß-cells. mt-tRF-LeuTAA fragment is derived from the cleavage of tRNA-LeuTAA encoded by the mitochondrial genome. We demonstrated that mt-tRF-LeuTAA acts as a key regulator of mitochondrial OXPHOS functions, mitochondrial membrane potential, the insulin secretory capacity of ß-cells, and the insulin sensitivity of myotube muscle cells. We sought to investigate the downstream mechanisms activated by this fragment. To gain a comprehensive understanding, we conducted proteomic analyses on rat islets with silenced mt-tRF-LeuTAA for 72 hours. Inhibiting mt-tRF-LeuTAA led to significant differential expression of 642 proteins, cut-off adjusted p ≤ 0.05. To further investigate the cellular rearrangement associated with the inhibition of mt-tRF-LeuTAA, we conducted enrichment analysis using Gene Ontology Molecular Function terms on mass spectrometry data. At the protein level, there was a significant enrichment of mitochondrial pathways, such as oxidoreductase activity, ATPase activity, hydrogen transport, NADH dehydrogenase activity, cytochrome-c oxidase activity, and oxygen transport. To elucidate the mechanisms by which mt-tRF-LeuTAA operates, we also conducted pull-down experiments in insulin-secreting INS832/13 cells, followed by mass spectrometry using 3'-biotinylated mimic sequence oligonucleotides of mt-tRF-LeuTAA. Our analysis unveiled interactions between mt-tRF-LeuTAA and 24 proteins, meeting the criteria of a fold change ≥ 6 and an adjusted p-value ≤ 0.05. Notably, among these proteins, 13 are localized within the mitochondria and play significant roles in mitochondrial oxidative functions. Some of these key proteins include Suclg2, Nme3, Sdha, Lrpprc, and Ndufa12. Pathway enrichment analysis of the binding partners associated with the mitochondrial fragment mt-tRF-LeuTAA indicates an over-representation of signaling pathways crucial to maintaining mitochondrial metabolism. These pathways include oxidative phosphorylation (OXPHOS), ROS-induced stress responses, the tricarboxylic acid (TCA) cycle, calcium homeostasis regulation, lipid metabolism, RNA splicing, and mitochondrial import, which all contribute fundamentally to the maintenance of mitochondrial metabolism. These findings collectively provide insights into the essential mechanisms underlining the functionality of mitochondrially-encoded tRNA-derived fragments with the view to sustaining mitochondrial metabolism.
2024-06-16 | PXD046117 | Pride
Project description:In this study, we discovered cytosolic and mitochondrial fragments resulting from tRNA and mt-tRNA cleavage, which may act as new regulators of cellular and metabolic functions. The so-called LP rat model consists of 22-day-old rats whose mothers have been subjected to a low protein diet during gestation and lactation. These offspring have impaired pancreatic development with reduced ß-cell mass, glucose-stimulated insulin secretion defect and are more prone to develop diabetes in adulthood. We identified hundreds of these fragments as being changed in the pancreatic islets of LP rats and compared them to chow diet (CD) exposed rats. In our analysis, we identified 6164 tRFs in the islets of LP rats, among which 256 exhibited significant changes (≥ 2 fold; adjusted p value ≤ 0.05) compared to controls. Of these, 113 tRFs showed increased levels, while 143 tRFs showed decreased levels in the LP rats. We focused our investigations on mitochondrial tRFs (mt-tRFs) that show significant alterations in both, adult pre-diabetic mice (db/db) and LP rats. We selected the mt-tRF-LeuTAA fragment for further investigation, as its level is reduced in the islets of db/db mice and LP rats, while being abundant in ß-cells. mt-tRF-LeuTAA fragment is derived from the cleavage of tRNA-LeuTAA encoded by the mitochondrial genome. We demonstrated that mt-tRF-LeuTAA acts as a key regulator of mitochondrial OXPHOS functions, mitochondrial membrane potential, the insulin secretory capacity of ß-cells, and the insulin sensitivity of myotube muscle cells.
2024-05-14 | GSE239981 | GEO
Project description:In this study, we discovered cytosolic and mitochondrial fragments resulting from tRNA and mt-tRNA cleavage, which may act as new regulators of cellular and metabolic functions. We analyzed hundreds of these fragments in the pancreatic islets of db/db mice and compared them to heterozygous control db/+ mice. At 16 weeks of age, db/db mice exhibit obesity, insulin resistance, and glucose intolerance. In our analysis, we identified 3858 tRFs in the islets of db/db mice, among which 342 exhibited significant changes (≥ 2 fold; adjusted p value ≤ 0.05) compared to controls. Of these, 199 tRFs showed increased levels, while 170 tRFs showed decreased levels in the pre-diabetic mice. Notably, a striking majority (147 out of 170) of the tRFs with reduced abundance in the islets of db/db mice were derived from the cleavage of tRNAs encoded by the mitochondrial genome. Our findings reveal a significant reshaping of mitochondrial tRFs in pre-diabetic conditions, coinciding with a well-established mitochondrial metabolic defect under these conditions. Specifically, we demonstrated that a fragment (named mt-tRF-LeuTAA) resulting from the cleavage of mt-tRNA-LeuTAA, encoded by the mitochondrial genome and found to be reduced in the islets of db/db mice, acts as a key regulator of mitochondrial OXPHOS functions, mitochondrial membrane potential, the insulin secretory capacity of ß-cells, and the insulin sensitivity of myotube muscle cells.
2024-05-14 | GSE239786 | GEO
Project description:Mitochondria are organelles that generate most of the energy in eukaryotic cells in the form of ATP via oxidative phosphorylation in eukaryote. Twenty-two species of mitochondrial (mt-)tRNAs encoded in mtDNA are required to translate essential subunits of the respiratory chain complexes involved in oxidative phosphorylation. mt-tRNAs contain post-transcriptional modifications introduced by nuclear-encoded tRNA-modifying enzymes. These modifications are required for deciphering genetic code accurately, as well as stabilizing tRNA. Loss of tRNA modifications frequently results in severe pathological consequences. We performed a comprehensive analysis of post-transcriptional modifications of all human mt-tRNAs, including 14 previously-uncharacterized species, and revised the modification status of some of the previously studied species. In total, we found 17 kinds of RNA modifications at 137 positions (8.7% in 1,575 nucleobases) in 22 species of human mt-tRNAs. An up-to-date list of 34 genes responsible for human mt-tRNA modifications are provided. We here demonstrated that both QTRT1 and QTRT2 are required for biogenesis of queuosine (Q) at position 34 of four mt-tRNAs. Our results provide insight into the molecular mechanisms underlying the mitochondrial decoding system, and could help to elucidate the molecular pathogenesis of human mitochondrial diseases caused by aberrant tRNA modifications.
2020-08-28 | GSE150439 | GEO
Project description:Background: As couples struggle with infertility and livestock producers wish to rapidly improve genetic merit in their herd, assisted reproductive technologies (ART) have become increasingly popular in human medicine as well as the livestock industry. Utilizing ART can cause an increased risk of congenital overgrowth syndromes, such as Large Offspring Syndrome (LOS) in ruminants. A dysregulation of transcripts has been observed in bovine fetuses with LOS, which is suggested to be a cause of the phenotype. Our recent study identified variations in tRNA expression in LOS individuals, leading us to hypothesize that variations in tRNA expression can influence the availability of their processed regulatory products, tRNA-derived fragments (tRFs). Due to their resemblance in size to microRNAs, studies suggest that tRFs target mRNA transcripts and regulate gene expression. Thus, we have sequenced small RNA isolated from skeletal muscle and liver of day 105 bovine fetuses to elucidate the mechanisms contributing to LOS. Moreover, we have utilized our previously generated tRNA sequencing data to analyze the contribution of tRNA availability to tRF abundance. Results: 22,289 and 7,737 unique tRFs were predicted in the liver and muscle tissue respectively. The greatest number of reads originated from 5′ tRFs in muscle and 5′ halves in liver. In addition, mitochondrial (MT) and nuclear derived tRF expression was tissue-specific with most MT-tRFs and nuclear tRFs derived from LysUUU and iMetCAU in muscle, and AsnGUU and GlyGCC in liver. Despite variation in tRF abundance within treatment groups, we identified differentially expressed (DE) tRFs across Control-AI, ART-Normal, and ART-LOS groups with the most DE tRFs between ART-Normal and ART-LOS groups. Many DE tRFs target transcripts enriched in pathways related to growth and development in the muscle and tumor development in the liver. Finally, we found positive correlation coefficients between tRNA availability and tRF expression in muscle (R = 0.47) and liver (0.6). Conclusion: Our results highlight the dysregulation of tRF expression and its regulatory roles in LOS. These tRFs were found to target both imprinted and non-imprinted genes in muscle as well as genes linked to tumor development in the liver. Furthermore, we found that tRNA transcription is a highly modulated event that plays a part in the biogenesis of tRFs. This study is the first to investigate the relationship between tRNA and tRF expression in combination with ART-induced LOS.
2022-11-15 | GSE213525 | GEO
Project description:Background: Colorectal liver metastases (CRLM) are the leading cause of colorectal cancer (CRC)-related mortality. Transfer RNA-derived fragments (tRFs), a novel class of small non-coding RNAs (sncRNA), regulate gene expression, stress response, and immune functions in cancer. While tRFs are increasingly implicated in CRC progression, their prognostic significance in CRLM remains unknown. This study investigates the abundance and prognostic value of genomic (ge) and mitochondrial (mt) tRFs in CRLM. Methods: This single-center retrospective cohort study included all CRLM patients who underwent curative liver resection between January 2012 and December 2015. Small RNA sequencing (sRNA-seq) quantified ge- and mt-tRF expression in tumor samples. Event-free survival (EFS) was the primary outcome, and the impact of tRFs on EFS was assessed using Cox regression, spline modeling of the effects of tRFs on EFS, and network analysis. Results: Among 588 screened samples, 40 met eligibility criteria (18 females [45%], median age 64 [42-79]). A total of 432 tRFs were identified, with ge-tRFs (67%) being more abundant than mt-tRFs (33%). Using spline regressions, tRFs were classified into 10 ten prognostic groups. High ge-tRF abundance correlated predominantly with unfavorable EFS (FDR<0.2; 94%), whereas mt-tRFs were significantly (p<0.001; χ2 test) more often associated with favorable EFS (FDR<0.2; 26%). Network analysis of tRF abundance correlations revealed a significantly higher intra-mitochondrial network density compared to the intra-genomic tRF network. However, no significant differences in network structure were observed between prognostically significant vs. non-significant or favorable vs. unfavorable tRFs. Finally, key tRF candidates, such as tRHalve3-His-CAU (mt-tRF) or tRNAleader-Gln-UUG (mt-tRF) paired with tRFmisc-Tyr-GTA (ge-tRF), remained independent prognostic markers after adjustment for clinical covariates. Conclusion: This study provides the first comprehensive characterization of tRF expression in CRLM, revealing distinct prognostic roles for ge- and mt-tRFs. While ge-tRFs were predominantly associated with unfavorable prognosis, a subset of mt-tRFs demonstrated a favorable impact on EFS. These findings highlight the potential of tRFs as novel prognostic biomarkers and therapeutic targets in CRLM, warranting validation in prospective studies.
2025-07-16 | GSE293849 | GEO
Project description:Mitochondrial DNA (mtDNA) mutations cause multisystem disorders, involving gastrointestinal (GI) dysfunction. However, the mechanism underlying the selection against mutant mtDNA and the impact of pathogenic mtDNA mutations on intestinal epithelial cells (IECs) remain unclear. Here, we employed mitochondrial single-cell assay for transposase-accessible chromatin with sequencing (mtscATAC-seq) to examine the heteroplasmy of IECs in m.G5081A (mt-tRNA) and m.G12918A (mt-mRNA) mutant mouse models over a two-year lifespan. Our findings reveal age-dependent purifying selection against mutant mtDNA across nine IEC subtypes, a process originating in intestinal stem cells (ISCs) that does not strengthen during cellular differentiation. Combining the analysis of single-cell RNA sequencing, we found that young mice with high m.G5081A mutation loads exhibit IEC dysfunction, including impaired enterocyte differentiation and defective Paneth cell granule formation. The m.G5081A mutant mice exhibit increased susceptibility to DSS-induced acute colitis due to compromised intestinal barrier function and impaired wound healing caused by the mtDNA mutation. Collectively, our findings reveal the cellular dynamics of mtDNA selection in IECs and demonstrate the functional consequences of mitochondrial dysfunction on intestinal health, providing insights relevant to mitochondrial disease pathogenesis and management.
2026-07-30 | GSE318907 | GEO
Project description:Mitochondrial DNA (mtDNA) mutations cause multisystem disorders, involving gastrointestinal (GI) dysfunction. However, the mechanism underlying the selection against mutant mtDNA and the impact of pathogenic mtDNA mutations on intestinal epithelial cells (IECs) remain unclear. Here, we employed mitochondrial single-cell assay for transposase-accessible chromatin with sequencing (mtscATAC-seq) to examine the heteroplasmy of IECs in m.G5081A (mt-tRNA) and m.G12918A (mt-mRNA) mutant mouse models over a two-year lifespan. Our findings reveal age-dependent purifying selection against mutant mtDNA across nine IEC subtypes, a process originating in intestinal stem cells (ISCs) that does not strengthen during cellular differentiation. Combining the analysis of single-cell RNA sequencing, we found that young mice with high m.G5081A mutation loads exhibit IEC dysfunction, including impaired enterocyte differentiation and defective Paneth cell granule formation. The m.G5081A mutant mice exhibit increased susceptibility to DSS-induced acute colitis due to compromised intestinal barrier function and impaired wound healing caused by the mtDNA mutation. Collectively, our findings reveal the cellular dynamics of mtDNA selection in IECs and demonstrate the functional consequences of mitochondrial dysfunction on intestinal health, providing insights relevant to mitochondrial disease pathogenesis and management.
2026-07-30 | GSE318904 | GEO