Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RNA sequencing”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,603 records · Page 89Linked to original sources

Accelerated probabilistic inference of RNA structure evolution.

BACKGROUND: Pairwise stochastic context-free grammars (Pair SCFGs) are powerful tools for evolutionary analysis of RNA, including simultaneous RNA sequence alignment and secondary structure prediction, but the associated algorithms are intensive in both CPU and memory usage. The same problem is faced by other RNA alignment-and-folding algorithms based on Sankoff's 1985 algorithm. It is therefore desirable to constrain such algorithms, by pre-processing the sequences and using this first pass to limit the range of structures and/or alignments that can be considered. RESULTS: We demonstrate how flexible classes of constraint can be imposed, greatly reducing the computational costs while maintaining a high quality of structural homology prediction. Any score-attributed context-free grammar (e.g. energy-based scoring schemes, or conditionally normalized Pair SCFGs) is amenable to this treatment. It is now possible to combine independent structural and alignment constraints of unprecedented general flexibility in Pair SCFG alignment algorithms. We outline several applications to the bioinformatics of RNA sequence and structure, including Waterman-Eggert N-best alignments and progressive multiple alignment. We evaluate the performance of the algorithm on test examples from the RFAM database. CONCLUSION: A program, Stemloc, that implements these algorithms for efficient RNA sequence alignment and structure prediction is available under the GNU General Public License.

Algorithms↗

Motor coordination and behavioural deficits in a mouse model of KMT2B-related dystonia.

INTRODUCTION: Pathogenic variants in KMT2B cause early-onset dystonia, but a mouse model that has undergone comprehensive, dystonia-oriented phenotyping is lacking. METHODS: We conducted detailed phenotyping on heterozygous Kmt2b constitutive knockout mice and wild-type littermates, assessing growth, neurobehavioural traits, motor coordination, sensorimotor gating, social behaviour and metabolic parameters, combined with striatal RNA sequencing. RESULTS: Kmt2b knockout mice of both sexes were viable but significantly smaller and lighter than littermate controls. Knockouts were hyperlocomotive in the open field and showed approximately two-fold larger acoustic startle responses; unexpectedly, prepulse inhibition was enhanced rather than reduced at all prepulse intensities. On the balance beam, knockouts crossed more slowly and paused more frequently; female knockouts also paused more on the ladder rung task. Frame-by-frame video analysis revealed a claw-like hindpaw posture characterized by abnormal inward flexion of the digits. Knockout mice spent less time investigating a novel conspecific, while social recognition memory remained intact. Striatal RNA sequencing confirmed reduction of Kmt2b transcript to approximately half of control levels and identified 177 differentially expressed genes, including Maob, encoding monoamine oxidase B; gene set enrichment analysis implicated neurodevelopmental, glial and mitochondrial processes. Nociception, vision, body-weight-adjusted grip strength, and clinical chemistry and haematological measures were largely unaffected. CONCLUSION: Heterozygous Kmt2b knockout mice show hyperlocomotion, altered sensorimotor gating, impaired motor coordination with dystonic-like paw posturing and reduced sociability, alongside a striatal transcriptomic signature implicating neurodevelopmental processes. The model mirrors aspects of human KMT2B-related dystonia and provides a platform for mechanistic study; environmental or pharmacological challenge may be needed to unmask overt dystonic features.

Dystonia↗

Reverse-transcriptase-associated RNaseH activity mediates template switching during reverse transcription in vitro.

During the first steps of reverse transcription of the retroviral genome, sequences present at the extremities of the RNA are used to reconstitute a host cell PolII promoter. The assembly of the promoter occurs by template switching, which takes advantage of a direct repeat at the ends of the RNA molecule. These steps are catalysed by the viral reverse transcriptase, which carries an intrinsic RNaseH activity that is probably also involved therein. To study the role of the RNaseH activity in this first template-switching event, an in vitro system has been developed based on primer extensions of synthetic RNAs. When an RNA was reverse transcribed with wild-type reverse transcriptase in the presence of a second RNA the 3' part of which was repeated at the 5' end of the first one, extension products could be observed corresponding to a chimeric cDNA comprising both RNA species. This template switching could not be detected when a mutant reverse transcriptase lacking the RNaseH activity was used. The results show that the RNaseH activity is needed to remove the 5' RNA sequences from the cDNA:RNA hybrid thereby enabling its translocation to another RNA containing an appropriate complementary target sequence.

Endoribonucleases↗

High spontaneous mutation rate of Rous sarcoma virus demonstrated by direct sequencing of the RNA genome.

Direct and extensive sequencing of RSV RNA genome is reported. More than 10,000 nt of the T1 RNase resistant RSV RNA fragments (1) have been sequenced and shown to cover 3900 nt of RSV genome. The frequent sequence variations found indicate that RSV supports a very high incidence of spontaneous mutations in the course of replication, one very probable cause of the genetic diversity among the avian retroviruses. Sequences of the structured RSV RNAs allowed us also to precisely characterize the structured domains of the retroviral genome and show that the src gene is not structured.

Amino Acid Sequence↗

Multiomic study of cutaneous T-cell lymphoma reveals single-cell clonal evolution in progression and therapy resistance.

Cutaneous T-cell lymphoma (CTCL) remains a challenging disease due to its significant heterogeneity, therapy resistance, and relentless progression. Multiomics technologies offer the potential to provide uniquely precise views of disease progression and response to therapy. Here, we present a comprehensive multiomics view of CTCL clonal evolution, incorporating exome, whole-genome, epigenome, bulk, single-cell T-cell receptor, and single-cell RNA sequencing of 99 clinically annotated serial skin, peripheral blood, and lymph node samples from 34 patients with CTCL. We leveraged this extensive data set to define the molecular underpinnings of CTCL progression in individual patients at single-cell resolution with the goal of identifying clinically useful biomarkers and therapeutic targets. Our studies identified recurrent progression-associated clonal genomic alterations; we highlight mutation of CCR4, phosphoinositide 3-kinase inhibitor signaling, and programmed cell death protein 1 (PD-1) checkpoint pathways as evasion tactics deployed by malignant T cells. We identified a gain-of-function mutation in STAT3 (D661Y) and demonstrated, using cleavage under targets and release using nuclease (CUT&RUN) and RNA sequencing, that it enhances binding to and transcription of genes in Rho GTPase pathways. With our previous work implicating this pathway in histone deacetylase inhibitor-resistant CTCL, these data provide further support for a previously unrecognized role for Rho GTPase pathway dysregulation in CTCL progression. Recurrent progression-associated mutations were common in the epigenetic modifier EZH2, suggesting that EZH2 inhibition may benefit patients with CTCL. Our findings support an approach in which genomic analysis is widely used for improved disease monitoring, biomarker-informed clinical trial design, and genome-guided therapeutic decision-making. Moreover, these molecular changes present new opportunities for therapeutic targeting in this challenging and incurable cancer.

Multiomics↗

Degradation of ribosomal RNA during Plasmodium falciparum gametocytogenesis.

The life cycle of Plasmodium falciparum is characterized by complex regulatory changes that allow adaptation of the parasites to different environmental conditions, which are especially pronounced during transmission between the mammalian host and the insect vector. Previous studies have shown that P. falciparum uses three types of ribosomal RNAs (rRNA A, S1, and S2 types) at different stages of its life cycle. We used Oxford Nanopore Technologies direct RNA sequencing to investigate the dynamics of rRNA usage throughout the parasite's intraerythrocytic development, as well as in salivary gland sporozoites. Our study revealed a preponderance of A-type rRNAs during the intraerythrocytic cycle and gametocytogenesis, while S-type rRNAs slowly increase in abundance in mosquito stages starting 3 days post-infection. Salivary gland sporozoites showed an even proportion of all rRNA types. By examining the length distributions of rRNA molecules, we detected an extensive and specific degradation of rRNAs during gametocytogenesis, starting in stage II gametocytes and continuing until the final stages of gametocyte development. We hypothesize that rRNA degradation may be linked to the global translational repression and metabolic quiescence described in stage V gametocytes, similar to mechanisms observed in bacterial and eukaryotic stress responses.IMPORTANCEOur study uses Oxford Nanopore direct RNA sequencing of tightly synchronized blood-stage Plasmodium falciparum parasites to investigate the expression of ribosomal RNAs during asexual and sexual development. P. falciparum utilizes distinct types of rRNA during its development. However, due to the challenges of differentiating these highly similar molecules, their regulation and the mechanism underlying the switch between rRNA types remain unclear. We observe significant rRNA degradation in mature gametocytes, leading us to propose that this potentially leads to a reduced number of functional ribosomes when parasites become quiescent and translation is repressed.

Plasmodium falciparum↗

Stage-specific ROMO1 in rheumatoid arthritis: predictive immune insights into the MIF pathway and HLA-DR/IL2RA axis via integrated GWAS, transcriptomic, single-cell, and spatial profiling.

Emerging evidence links reactive oxygen species modulator 1 (ROMO1), a key mitochondrial ROS regulator, to rheumatoid arthritis (RA) pathogenesis. However, its exact mechanism remains elusive given the conflicting evidence about its specific function. We used a four-level integrative framework combining multi-omics data and literature‑supported mechanistic inference. At the genetic level, Mendelian randomization (MR) was performed to explore potential causal relationships between ROMO1, IL2RA, HLA-DR, MIF, and RA risk, followed by differential expression analysis and machine learning-based feature selection to identify key mROS genes. The temporal expression dynamics of ROMO1 were assessed in RA progression. At the cellular and tissue levels, we integrated single-cell RNA sequencing and spatial transcriptomics to map cell-type-specific expression and synovial localization of ROMO1-related immune cells and pathways. Finally, our multi-omics findings were contextualized with literature-supported mechanistic inference. (1) MR results were consistent with a potential protective effect of ROMO1 on RA (OR = 0.52) and its potential regulation of risk factors IL2RA (OR = 0.46) and HLA-DR (OR = 0.40). Conversely, IL2RA (OR = 1.42), HLA-DR (OR = 1.88), and MIF (OR = 1.17) were positively associated with RA risk. Additionally, ROMO1 was identified as a top candidate diagnostic predictor with stage-specific dynamics: downregulated in the early but upregulated in the late/remission stages. (2) Single-cell RNA sequencing showed ROMO1's cell-specific expression in CD14+ HLA-DR+ CD74+ monocytes and CD4+ IL2RA+ T cells. Cell communication analysis further suggested that these cells may participate in MIF pathway regulation. Spatial transcriptomics subsequently identified that ROMO1-related cells localized to synovial pathological regions, with MIF pathway changes correlated with RA progression. (3) Finally, literature-supported mechanistic inference suggests that ROMO1 may modulate mROS levels to promote anti-inflammatory M2 macrophage polarization, which could theoretically contribute to reduced systemic inflammation and the alleviation of multi-organ decline in RA. This integrated multi-omics investigation, supported by literature-based mechanistic inference, suggests ROMO1 as a stage-dependent biomarker candidate and potential immune regulator in RA.

Humans↗

Pan-cancer analysis identifies APOC1 as a TAM-derived modulator of adaptive immune resistance and predictor of therapeutic response.

BACKGROUND: Apolipoprotein C1 (APOC1) has been implicated in several malignancies, yet its expression patterns, clinical significance, and immunomodulatory roles across cancer types remain poorly characterized. METHODS: We performed a comprehensive multi-omic analysis of APOC1 across 33 cancer types integrating transcriptomic, proteomic, genomic, epigenomic, and pharmacogenomic data from TCGA, GTEx, CPTAC, and multiple independent external cohorts. Immune infiltration was assessed using seven complementary algorithms. Spatial transcriptomics and single-cell RNA sequencing were employed to determine the cellular source of APOC1 expression. RESULTS: APOC1 upregulation in most cancers was associated with cancer type-specific prognosis. After adjustment for clinical covariates and macrophage infiltration, high APOC1 remained an independent adverse factor in KIRC, LGG, and STAD. APOC1 expression positively correlated with genomic instability hallmarks, including homologous recombination deficiency and aneuploidy, with these associations largely independent of immune infiltration; in contrast, associations with tumor mutational burden were substantially confounded by macrophage abundance. Immune infiltration analysis revealed a pattern consistent with adaptive immune resistance: APOC1 correlated positively with immune-activating signatures (STAT1, MHC-II, TCR signaling) and immunosuppressive M2 macrophages and Tregs, yet negatively with anti-tumor effectors (activated NK cells, dendritic cells). Spatial transcriptomics and single-cell RNA sequencing identified tumor-associated macrophages (TAMs) as the primary cellular source of APOC1, with transcripts co-localizing with CD68 in tissue sections. APOC1 expression correlated with multiple immune checkpoint molecules and was elevated in responders to immune checkpoint blockade, consistent with an inflamed yet regulated tumor microenvironment. Pharmacogenomic analyses revealed that APOC1-high tumors display distinct drug response profiles, characterized by resistance to MAPK pathway inhibitors and potential sensitivity to the HDAC inhibitor Entinostat. CONCLUSION: This pan-cancer analysis establishes APOC1 as a context-dependent biomarker and a TAM-derived modulator of adaptive immune resistance, with prognostic and therapeutic implications across malignancies. APOC1-expressing TAMs represent a potential target for combination immunotherapy strategies.

APOC1↗

Identification of immune cell type-specific susceptibility genes in multiple cancers using transcriptome-wide association studies.

BACKGROUND: Transcriptome-wide association studies (TWAS) integrate gene expression and genome-wide association studies (GWAS) to identify disease susceptibility genes. Because gene expression varies substantially across cell types within tissues, cell type-specific prediction models may enhance the power of TWAS. METHODS: We conducted cell type-specific TWAS leveraging single-cell RNA sequencing data from the OneK1K cohort (14 immune cell types, 1.27 million cells) and GWAS summary statistics for 7 cancers (>290 000 cases in total). To improve prediction accuracy, we developed a modeling framework that incorporates shared gene expression effects across cell types. RESULTS: At a false discovery rate of 5%, we identified 106 (Bonferroni 5%: 13) previously unreported loci for breast cancer, 51 (4) loci for prostate cancer, 11 (4) loci for lung cancer, 39 (5) loci for melanoma, 9 (1) loci for ovarian cancer, and 2 (1) loci for diffuse large B-cell lymphoma, with most genes exhibiting cell type specificity. Gene set analyses confirmed joint associations of unreported genes with breast and prostate cancer risk in UK Biobank data. Additional lung tissue single-cell RNA sequencing data with 113 individuals validated 18 of 32 (56.3%) statistically significant genes for lung cancer. Across cancers, 139 statistically significant genes were shared by at least 2 cancer types and were primarily enriched in specific immune cell types. CONCLUSION: Cell type-specific TWAS improve the identification of novel cancer susceptibility loci and provide insights into the immune landscape of cancer etiology.

Humans↗

Ribonucleic acid-protein cross-linking within the intact Escherichia coli ribosome, utilizing ethylene glycol bis[3-(2-ketobutyraldehyde) ether], a reversible, bifunctional reagent: identification of 30S proteins.

To obtain detailed topographical information concerning the spatial arrangement of the multitude of ribosomal proteins with respect to specific sequences in the three RNA chains of intact ribosomes, a reagent capable of covalently and reversibly joining RNA to protein has been synthesized [Brewer, L.A., Goelz, S., & Noller, H. F. (1983) Biochemistry (preceding paper in this issue)]. This compound, ethylene glycol bis[3-(2-ketobutyraldehyde) ether] which we term "bikethoxal", possesses two reactive ends similar to kethoxal. Accordingly, it reacts selectively with guanine in single-stranded regions of nucleic acid and with arginine in protein. The cross-linking is reversible in that the arginine- and guanine-bikethoxal linkage can be disrupted by treatment with mild base, allowing identification of the linked RNA and protein components by standard techniques. Further, since the sites of kethoxal modification within the RNA sequences of intact subunits are known, the task of identifying the components of individual ribonucleoprotein complexes should be considerably simplified. About 15% of the ribosomal protein was covalently cross-linked to 16S RNA by bikethoxal under our standard reaction conditions, as monitored by comigration of 35S-labeled protein with RNA on Sepharose 4B in urea. Cross-linked 30S proteins were subsequently removed from 16S RNA by treatment with T1 ribonuclease and/or mild base cleavage of the reagent and were identified by two-dimensional polyacrylamide gel electrophoresis. The major 30S proteins found in cross-linked complexes are S4, S5, S6, S7, S8, S9 (S11), S16, and S18. The minor ones are S2, S3, S12, S13, S14, S15, and S17.

Aldehydes↗

Circadian control of messenger RNA stability. Association with a sequence-specific messenger RNA decay pathway.

Transcriptional and posttranscriptional regulation are well-established mechanisms for circadian gene expression. Among the latter, differential messenger RNA (mRNA) stability has been hypothesized to control gene expression in response to the clock. However, direct proof that the rate of mRNA turnover can be regulated by the clock is lacking. Previous microarray expression data for unstable mRNAs in Arabidopsis (Arabidopsis thaliana) revealed that mRNA instability is associated with a group of genes controlled by the circadian clock. Here, we show that CCR-LIKE (CCL) and SENESCENCE ASSOCIATED GENE 1 transcripts are differentially regulated at the level of mRNA stability at different times of day. In addition, the changes in CCL mRNA stability continue under free-running conditions, indicating that it is controlled by the Arabidopsis circadian clock. Furthermore, we show that these mRNAs are targets of the mRNA degradation pathway mediated by the downstream (DST) instability determinant. Disruption of the DST-mediated decay pathway in the dst1 mutant leads to aberrant circadian mRNA oscillations that correlate with alterations of the half-life of CCL mRNA relative to parental plants in the morning and afternoon. That this is due to an effect on the circadian control is evidenced by mRNA decay experiments carried out in continuous light. Finally, we show that the defects exhibited by dst mutants are reflected by an impact on circadian regulation at the whole plant level. Together, these results demonstrate that regulation of mRNA stability is important for clock-controlled expression of specific genes in Arabidopsis. Moreover, these data uncover a connection between circadian rhythms and a sequence-specific mRNA decay pathway.

Arabidopsis↗

Therapeutic Targeting of Decr1 Ameliorates Cardiomyopathy by Suppressing Mitochondrial Fatty Acid Oxidation in Diabetic Mice.

BACKGROUND: A significant increase in mitochondrial fatty acid oxidation (FAO) is now increasingly recognized as one of the metabolic alterations in diabetic cardiomyopathy (DCM). However, the molecular mechanisms underlying mitochondrial FAO impairment in DCM remain to be fully elucidated. METHODS: A type 2 diabetes (T2D) mouse model was established by a combination of high-fat diet (HFD) and streptozotocin (STZ) injection. Neonatal rat cardiomyocytes were treated with high glucose (HG) and palmitic acid (HP) to simulate diabetic cardiac injury. Gain- and loss-of-function approaches and RNA sequencing were utilized to investigate the role and mechanism of 2,4-dienoyl-CoA reductase 1 (Decr1) in DCM. RESULTS: By integrating the genomic data available in the Gene Expression Omnibus (GEO) with DCM rodents, we found that the transcriptional level of Decr1 was consistently upregulated in DCM (+255% for diabetic heart, p&#x2009;<&#x2009;0.0001; +281% for diabetic cells, p&#x2009;<&#x2009;0.0001). Cardiomyocytes-specific knockdown of Decr1 preserved cardiac function (+41% for EF, p&#x2009;<&#x2009;0.0001; +24% for FS, p&#x2009;=&#x2009;0.0052), inhibited cardiac hypertrophy (-34%, p&#x2009;<&#x2009;0.0001), fibrosis (-69%, p&#x2009;<&#x2009;0.0001), apoptosis (-56%, p&#x2009;<&#x2009;0.0001) and oxidative damage (-59%, p&#x2009;<&#x2009;0.0001) in DCM mice, while cardiomyocytes-specific overexpression of Decr1 aggravated DCM (-28% for EF, p&#x2009;=&#x2009;0.0347; -17% for FS, p&#x2009;=&#x2009;0.0014). Deletion of Decr1 prevented high glucose/palmitate (HG/HP)-induced hypertrophy (-22%, p&#x2009;=&#x2009;0.0006), mitochondrial dysfunction and apoptosis (-74%, p&#x2009;<&#x2009;0.0001) in cultured cardiomyocytes. Furthermore, RNA sequencing and functional analysis showed that Decr1 interacted with and upregulated pyruvate dehydrogenase kinase 4 (PDK4) in injured cardiomyocytes, and overexpression of PDK4 eliminated the benefits of Decr1 downregulation in DCM (-20% for EF, p&#x2009;=&#x2009;0.0071; -28% for FS, p&#x2009;=&#x2009;0.0022). Mechanistically, PDK4 acted as a kinase that induced phosphorylation and mitochondrial translocation of HDAC3. In the mitochondria, HDAC3 mediated the deacetylation of dehydrogenase trifunctional multienzyme complex &#x3b1; subunit (HADHA), contributing to excessive mitochondrial FAO and subsequent cardiac injury. From a screening of 256 natural products, we identified Atranorin and Kurarinone as potential inhibitors of Decr1, both demonstrating protective effects against DCM (Atranorin, +21% for EF, p&#x2009;=&#x2009;0.0134; +24% for FS, p&#x2009;=&#x2009;0.0006; Kurarinone, +20% for EF, p&#x2009;=&#x2009;0.0183; +27% for FS, p&#x2009;=&#x2009;0.0001). CONCLUSIONS: Our study delineates a molecular mechanism by which Decr1 potentiated higher mitochondrial lipid oxidation and cardiac damage by enhancing HADHA deacetylation through the PDK4/HDAC3 signalling pathway.

Animals↗

Epigallocatechin gallate is associated with PDGFRB downregulation and altered PI3K-AKT signaling in gastric cancer.

BACKGROUND: Gastric cancer (GC) remains a major cause of cancer-related mortality worldwide. Epigallocatechin gallate (EGCG), a natural polyphenol derived from green tea, exhibits anticancer properties; however, its molecular targets and regulatory mechanisms in GC are not fully elucidated. This study aimed to identify candidate EGCG-associated genes in GC and generate a hypothesis for future mechanistic investigation. METHODS: Differentially expressed genes (DEGs) in GC were identified and intersected with EGCG-associated targets retrieved from The Cancer Genome Atlas (TCGA) and GeneCards public databases. Least absolute shrinkage and selection operator (LASSO) regression and Cox proportional hazards analyses were performed to screen prognostically relevant genes. Diagnostic performance was evaluated using receiver operating characteristic (ROC) curves. Functional enrichment analysis was conducted to explore biological significance. Public single-cell RNA sequencing datasets were analyzed to determine the cellular localization of platelet-derived growth factor receptor beta (PDGFRB), while DepMap transcriptomic data were used to assess its expression across GC cell lines. In vitro assays, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Transwell migration, and Western blotting, were performed to evaluate the biological effects of EGCG on GC-associated signaling pathways. RESULTS: Thirty-eight EGCG-associated DEGs were identified. Enrichment analysis revealed these genes were involved in cancer-associated pathways. LASSO-Cox modelling identified four candidate genes. Among them, PDGFRB was selected for further investigation based on its prognostic relevance and favorable diagnostic performance. PDGFRB expression was significantly higher in the TCGA genomically stable (GS) subtype than in the other molecular subtypes and was predominantly localized to cancer-associated fibroblasts (CAFs) and pericytes in single-cell RNA sequencing analysis. DepMap data demonstrated heterogeneous PDGFRB expression across GC cell lines. In vitro experiments showed that EGCG inhibited proliferation, migration, and invasion, reduced PDGFRB protein expression, and was associated with apoptosis-related protein changes and altered PI3K-AKT signaling. CONCLUSIONS: Our findings suggest that EGCG treatment was associated with reduced PDGFRB expression and altered PI3K-AKT signaling in GC cells. These findings identify PDGFRB as a candidate EGCG-associated gene and provide a hypothesis for future mechanistic investigation.

Gastric cancer (GC)↗

YAP Promotes Microtubule Growth to Facilitate Sarcomere Disassembly in Adult Cardiomyocytes.

BACKGROUND: Mature mammalian cardiomyocytes (CMs) develop compact sarcomeric structures that inhibit proliferation. Consequently, CMs must dedifferentiate to a fetus-like state, which is accompanied by sarcomere disassembly, to enable successful cytokinesis. However, the regulation and coordination of CM dedifferentiation, cell cycle progression, and sarcomere reorganization remain unclear. METHODS: We generated adenovirus and adeno-associated virus (MyoAAV) vectors expressing YAP5SA and YAP5SA-S94A under Xon control for LMI070-inducible protein expression. We also developed MyoAAV-cTnT-Tuba1b-shRNA-miR30 for cardiomyocyte-specific knockdown of Tuba1b. These tools were used to investigate CM dedifferentiation and proliferation and sarcomere disassembly. We also performed Cleavage Under Targets and Release Using Nuclease to map the genome-wide binding sites of YAP5SA and YAP5SA-S94A in combination with RNA sequencing to identify YAP target genes. In addition, time-course live-imaging analysis was used to evaluate microtubule and sarcomere dynamics in adult CMs. RESULTS: We show that microtubule expression and network density decline with cardiac maturation. Overexpression of YAP5SA, a constitutively active YAP mutant, promotes microtubule growth by stabilizing microtubule dynamics, leading to CM dedifferentiation, cell cycle re-entry, and sarcomere disassembly. In contrast, colchicine blocks these processes and significantly attenuates YAP-induced cardiac regeneration. Live imaging reveals a distinct mode of sarcomere disassembly driven by enhanced microtubule polymerization, wherein microtubule plus-ends directly interact with &#x3b1;-actinin and displace &#x3b1;-actinin fragments, thereby facilitating sarcomere breakdown. Furthermore, the YAP5SA-S94A mutation, which disrupts the YAP and TEA domain interaction, significantly reduces YAP5SA-induced microtubule growth, sarcomere disassembly, and cell cycle activity. Mechanistically, cleavage under targets and release using nuclease combined with RNA sequencing identified direct YAP targets, including Ajuba and Tuba1b, which are critical for microtubule growth. CM-specific knockdown of Tuba1b attenuates YAP-driven sarcomere disassembly. CONCLUSIONS: These findings identify microtubule networks as an essential regulator modulating CM dedifferentiation and sarcomere reorganization, which is critical for CM cytokinesis and cardiac regenerative repair.

Animals↗

Analysis of the terminal sequences of the genome segments of four orbiviruses.

The RNA sequences of the terminal regions of the genome segments of 4 different orbiviruses were analysed. In 3 of these [bluetongue virus (BTV) types 1 and 20 and Ibaraki virus, a member of the epizootic hemorrhagic disease (EHD) serogroup], 1 strand of all of the genome segments analysed ends in 3'CAAUUU...5' while the other strand ends in 3'CAUUCA...5'. These conserved sequences are identical to those reported for BTV types 10 and 11. The 3' terminal sequences of segments 3 and 10 of the BTV 1 genome (including the conserved regions) were confirmed by the detection of exactly complementary sequences at the 5' termini of the ssRNA strands of opposite polarity. This also confirmed for these dsRNA segments (and by analogy for all of the genome segments of these viruses) that the dsRNA molecules are fully base-paired end to end. Using in vitro synthesised mRNA of BTV 1 in annealing experiments with the separated ssRNAs from the individual genome segments, it was shown that in each case the strand ending in 3'CAUUCA...5' is of the same polarity as the mRNA (+ve), while the strand ending in 3'CAAUUU...5' is of the opposite (-ve) polarity. The 4th virus analysed (Tilligerry, a member of the Eubenangee serogroup) only had 5 conserved bases at the 3' termini of 1 strand of each genome segment (3'CAU-CA...5') and 3 conserved bases at the 3' termini of the other strand (3'CA--U...5'). Considerable sequence homology was found in the near-terminal nonconserved regions of comparable genome segments, particularly between the different BTV types. There was little evidence however for absolute conservation of "segment specific" sequences in these regions of the RNA, as reported for rotaviruses. The percentage of sequence homology found in the terminal regions of the genome segments between members of the BTV, EHD and Eubenangee serogroups examined correlates with the serological interrelationships between these groups of viruses. The conserved terminal sequences and sequence homology in these regions of the RNA are discussed as to their role in virus replication and their significance to the reassortment of genome segments between different viruses during dual infections.

Base Sequence↗

Comparison of 18S ribosomal RNA gene sequences of Eurytrema coelmaticum and Eurytrema pancreaticum.

The partial 18S rRNA sequences of E. coelmaticum and E. pancreaticum were amplified using conserved primers and an evolutionary tree was constructed using Neighbor-Joining. The percent identity of Eurytrema species with other Dicrocoeliidae varied from 97.5 to 98.2, while the percent identity between the two Eurytrema species was up to 99.3. The tree showed that E. coelmaticum and E. pancreaticum were not situated in the same position, and they formed one cluster with L. collurioni. These results support a confirmation with molecular data that E. coelomaticum and E. pancreaticum are different species which apparently were not seriously questioned in the past.

Animals↗

Single-nucleus profiling reveals hepatocyte identity and immune features associated with corticosteroid response in severe alcohol-related hepatitis.

BACKGROUND & AIMS: Severe alcohol-related hepatitis (sAH) is associated with high short-term mortality. However, 30-40% of patients fail to respond to corticosteroids, the only proven pharmacological treatment. The pathophysiological mechanisms underlying sAH and the marked heterogeneity in treatment response remain incompletely understood. We aimed to define cellular changes associated with corticosteroid response in sAH and to identify baseline markers predictive of treatment outcome. METHODS: Single-nucleus RNA sequencing was performed on liver biopsies from patients with biopsy-proven sAH (n = 17), including paired baseline and day 8 biopsies in a subset of patients (n = 8). Patients were classified as corticosteroid responders (sAH-R; Lille score <0.45) or non-responders (sAH-NR; Lille score &#x2265;0.45). Liver biopsies from patients with acute decompensation of alcohol-related cirrhosis (AD; n = 5) and healthy controls (n = 4) were included for comparison. Findings were validated using immunohistochemistry and spatial proteomics in a large multicenter validation cohort (n = 172). RESULTS: At baseline, sAH-R exhibited a significantly higher proportion of liver-infiltrating S100A8+ monocytes compared to sAH-NR, a difference that persisted at day 8. sAH livers showed a marked reduction in mature hepatocytes and an expansion of stressed and intermediate hepatocyte populations, indicating progressive loss of mature hepatocyte identity. This loss was more pronounced in sAH-NR, who also exhibited fewer cycling hepatocytes at day 8, consistent with impaired regenerative capacity. Expression of SULT2A1, a marker of mature hepatocyte identity, was significantly reduced in sAH-NR at baseline. Finally, liver biopsies with &#x2265;50% SULT2A1-positive hepatocytes at baseline were strongly predictive of corticosteroid response. CONCLUSIONS: This study delineates distinct immune and hepatocyte changes associated with corticosteroid response in sAH. Baseline SULT2A1 expression may facilitate stratified treatment approaches in sAH. IMPACT AND IMPLICATIONS: Severe alcohol-related hepatitis (sAH) represents one of the most devastating manifestations of alcohol-related disorders. sAH is characterized by acute hepatic inflammation and high short-term mortality. Clinical management remains challenging, as corticosteroids - the only pharmacological therapy currently applied - are ineffective in a substantial proportion of patients and are associated with significant adverse effects. These limitations highlight the need for a more detailed understanding of sAH pathophysiology and for approaches that enable improved patient stratification and therapeutic decision-making. In this study, we identify distinct pre-treatment differences between corticosteroid responders and non-responders at the level of both hepatocytes and myeloid cells, providing new insight into the cellular mechanisms underlying treatment heterogeneity in sAH. Furthermore, leveraging these findings, we developed a histology-based SULT2A1 scoring system using a commercially available antibody, which predicts corticosteroid response at baseline and may support stratified treatment approaches in clinical practice.

Humans↗

ER proteostasis failure in HYOU1 deficiency alters B cells, neutrophils, and interferon signalling.

Hypoxia upregulated 1 (HYOU1) is a stress-inducible ER chaperone. We investigated 2 unrelated patients carrying biallelic HYOU1 variants and presenting with primary immunodeficiency. Patient 1, homozygous for p.Pro444His, displayed failure to thrive, hypoglycemia, B cell lymphopenia, and neutropenia. Patient 2, compound heterozygous for p.Arg262Gln and p.Pro757_Glu758insAla, exhibited recurrent infections, enteropathy, and hypogammaglobulinemia. In Patient 1, while HYOU1 transcription was preserved, the protein was severely reduced. Tunicamycin treatment of dermal fibroblasts showed a blunted unfolded protein response and defective induction of ER stress-responsive genes. Immunophenotyping showed near-absence of circulating B cells, and single-cell RNA sequencing of bone marrow identified an arrest at the pro-B cell stage. Neutrophils displayed hypogranulation and dysregulated IFN- and apoptosis-associated transcriptional signatures, unresponsive to G-CSF. HYOU1 deficiency hence results in ER stress-induced proteostasis failure that simultaneously impairs adaptive immunity through B cell developmental arrest and innate immunity through neutrophil dysfunction and IFN pathway imbalance. This work expands the spectrum of HYOU1 deficiency and further identifies ER proteostasis as a central determinant of immune homeostasis.

Journal Article↗