RESUMEN
Full-length transcription in the majority of human genes depends on U1 snRNP (U1) to co-transcriptionally suppress transcription-terminating premature 3' end cleavage and polyadenylation (PCPA) from cryptic polyadenylation signals (PASs) in introns. However, the mechanism of this U1 activity, termed telescripting, is unknown. Here, we captured a complex, comprising U1 and CPA factors (U1-CPAFs), that binds intronic PASs and suppresses PCPA. U1-CPAFs are distinct from U1-spliceosomal complexes; they include CPA's three main subunits, CFIm, CPSF, and CstF; lack essential splicing factors; and associate with transcription elongation and mRNA export complexes. Telescripting requires U1:pre-mRNA base-pairing, which can be disrupted by U1 antisense oligonucleotide (U1 AMO), triggering PCPA. U1 AMO remodels U1-CPAFs, revealing changes, including recruitment of CPA-stimulating factors, that explain U1-CPAFs' switch from repressive to activated states. Our findings outline this U1 telescripting mechanism and demonstrate U1's unique role as central regulator of pre-mRNA processing and transcription.
Asunto(s)
Núcleo Celular/metabolismo , Factor de Especificidad de Desdoblamiento y Poliadenilación/metabolismo , División del ARN , Precursores del ARN/biosíntesis , ARN Mensajero/biosíntesis , Ribonucleoproteína Nuclear Pequeña U1/metabolismo , Transcripción Genética , Regiones no Traducidas 3' , Transporte Activo de Núcleo Celular , Sitios de Unión , Núcleo Celular/genética , Factor de Especificidad de Desdoblamiento y Poliadenilación/genética , Factor de Estimulación del Desdoblamiento/genética , Factor de Estimulación del Desdoblamiento/metabolismo , Células HeLa , Humanos , Complejos Multiproteicos , Poli A/metabolismo , Unión Proteica , Precursores del ARN/genética , ARN Mensajero/genética , Ribonucleoproteína Nuclear Pequeña U1/genéticaRESUMEN
Oral mucositis (OM) is a common side effect in patients with cancer receiving chemotherapy and radiotherapy; however, no salivary mediator is known to be associated with OM. We aimed to determine candidate salivary inflammatory mediators potentially associated with OM in patients with cancer. To this end, we compared the relationships between OM grade, oral mucosal dryness, and inflammatory mediators (Interleukin (IL)-1ß, IL-6, IL-10, IL-12p70, tumor necrosis factor (TNF), prostaglandin E2, and vascular endothelial growth factor) in patients with cancer and in healthy volunteers (HV). We collected saliva samples from 18 patients with cancer according to the following schedule: 1) within 14 days of treatment initiation, 2) within 3 days of OM occurrence, 3) when OM was improved or got worsened, and 4) within 7 days after chemotherapy completion. The oral care support team determined the OM grade at each sample collection point based on CTCAE version 5.0. Salivary inflammatory mediator concentrations were detected using cytometric bead array or enzyme-linked immunoassay. We compared oral mucosal dryness in pre- and post-index patients with cancer to that in HV (n = 33) using an oral moisture-checking device. Fourteen of eighteen patients experienced OM (four, grade 3 OM; four, grade 2 OM; six, grade 1 OM). IL-6, IL-10, and TNF salivary concentrations were significantly increased in the post-index group compared to those in the pre-index group (p = 0.0002, p = 0.0364, and p = 0.0160, respectively). Additionally, salivary IL-6, IL-10, and TNF levels were significantly higher in the post-index group than in the HV group (p < 0.0001, p < 0.05, and p < 0.05, respectively). Significant positive correlations were observed between OM grade and salivary IL-6, IL-10, and TNF levels (p = 0.0004, r = 0.4939; p = 0.0171, r = 0.3394; and p = 0007, r = 0.4662, respectively). Oral mucosal dryness was significantly higher in the HV than in the pre- and post-index groups (p < 0.001). Our findings suggest that salivary IL-6, IL-10, and TNF levels may be used as biomarkers for OM occurrence and grade in patients with cancer. Furthermore, monitoring oral mucosal dryness and managing oral hygiene before cancer treatment is essential.
Asunto(s)
Neoplasias , Estomatitis , Xerostomía , Biomarcadores/metabolismo , Humanos , Mediadores de Inflamación/metabolismo , Interleucina-10/metabolismo , Interleucina-6/metabolismo , Neoplasias/complicaciones , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Proyectos Piloto , Saliva/metabolismo , Estomatitis/etiología , Estomatitis/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Xerostomía/metabolismoRESUMEN
Stimulated cells and cancer cells have widespread shortening of mRNA 3'-untranslated regions (3'UTRs) and switches to shorter mRNA isoforms due to usage of more proximal polyadenylation signals (PASs) in introns and last exons. U1 snRNP (U1), vertebrates' most abundant non-coding (spliceosomal) small nuclear RNA, silences proximal PASs and its inhibition with antisense morpholino oligonucleotides (U1 AMO) triggers widespread premature transcription termination and mRNA shortening. Here we show that low U1 AMO doses increase cancer cells' migration and invasion in vitro by up to 500%, whereas U1 over-expression has the opposite effect. In addition to 3'UTR length, numerous transcriptome changes that could contribute to this phenotype are observed, including alternative splicing, and mRNA expression levels of proto-oncogenes and tumor suppressors. These findings reveal an unexpected role for U1 homeostasis (available U1 relative to transcription) in oncogenic and activated cell states, and suggest U1 as a potential target for their modulation.
Asunto(s)
Movimiento Celular , Neoplasias/metabolismo , Ribonucleoproteína Nuclear Pequeña U1/metabolismo , Línea Celular Tumoral , Humanos , Invasividad Neoplásica , Neoplasias/genética , Neoplasias/patología , Neoplasias/fisiopatología , Oligonucleótidos Antisentido/genética , Oligonucleótidos Antisentido/metabolismo , Empalme del ARN , ARN Mensajero/metabolismo , Ribonucleoproteína Nuclear Pequeña U1/genéticaRESUMEN
Two groups of Chinese hypertriacylglycerolemic subjects were recruited and randomized to medium- and long-chain triacylglycerols (MLCT) oil or long-chain triacylglycerols (LCT) oil. Two subgroups were divided by age at less or more 60 years in both groups. Both oils were consumed at 25-30 g daily for 8 weeks. Anthropometry, blood biochemicals, and computed tomography (CT) scanning were done at the initial and final times. In subjects of age less than 60 years on MLCT, the body weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-hip ratio (WHR), body fat, total fat area, and subcutaneous fat area were significantly lower than those of the initial values, and the change values in these indicators and visceral fat area lowered significantly as compared with those on LCT. The levels of apoB, apoA2, apoC2, and apoC3 decreased significantly, and the change in values in the levels of triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), apoA1, apoB, apoA2, apoC2, apoC3 were significantly lower on MLCT of age under 60 years as compared with those on LCT.
Asunto(s)
Grasas de la Dieta/farmacología , Ácidos Grasos/química , Hipertrigliceridemia , Triglicéridos/química , Triglicéridos/farmacología , Tejido Adiposo/efectos de los fármacos , Adulto , Distribución por Edad , Anciano , Apolipoproteínas/sangre , Pueblo Asiatico , Glucemia/metabolismo , Colesterol/sangre , Ingestión de Energía , Femenino , Humanos , Hipertrigliceridemia/sangre , Hipertrigliceridemia/enzimología , Hipertrigliceridemia/fisiopatología , Masculino , Actividad Motora , Triglicéridos/sangreRESUMEN
Telescripting is a fundamental cotranscriptional gene regulation process that relies on U1 snRNP (U1) to suppress premature 3'-end cleavage and polyadenylation (PCPA) in RNA polymerase II (Pol II) transcripts, which is necessary for full-length transcription of thousands of protein-coding (pre-mRNAs) and long noncoding (lncRNA) genes. Like U1 role in splicing, telescripting requires U1 snRNA base-pairing with nascent transcripts. Inhibition of U1 base-pairing with U1 snRNA antisense morpholino oligonucleotide (U1 AMO) mimics widespread PCPA from cryptic polyadenylation signals (PASs) in human tissues, including PCPA in introns and last exons' 3'-untranslated regions (3' UTRs). U1 telescripting-PCPA balance changes generate diverse RNAs depending on where in a gene it occurs. Long genes are highly U1-telescripting-dependent because of PASs in introns compared to short genes. Enrichment of cell cycle control, differentiation, and developmental functions in long genes, compared to housekeeping and acute cell stress response genes in short genes, reveals a gene size-function relationship in mammalian genomes. This polarization increased in metazoan evolution by previously unexplained intron expansion, suggesting that U1 telescripting could shift global gene expression priorities. We show that that modulating U1 availability can profoundly alter cell phenotype, such as cancer cell migration and invasion, underscoring the critical role of U1 homeostasis and suggesting it as a potential target for therapies. We describe a complex of U1 with cleavage and polyadenylation factors that silences PASs in introns and 3' UTR, which gives insights into U1 telescripting mechanism and transcription elongation regulation.
RESUMEN
U1 snRNP (U1) functions in splicing introns and telescripting, which suppresses premature cleavage and polyadenylation (PCPA). Using U1 inhibition in human cells, we show that U1 telescripting is selectively required for sustaining long-distance transcription elongation in introns of large genes (median 39 kb). Evidence of widespread PCPA in the same locations in normal tissues reveals that large genes incur natural transcription attrition. Underscoring the importance of U1 telescripting as a gene-size-based mRNA-regulation mechanism, small genes were not sensitive to PCPA, and the spliced-mRNA productivity of â¼1,000 small genes (median 6.8 kb) increased upon U1 inhibition. Notably, these small, upregulated genes were enriched in functions related to acute stimuli and cell-survival response, whereas genes subject to PCPA were enriched in cell-cycle progression and developmental functions. This gene size-function polarization increased in metazoan evolution by enormous intron expansion. We propose that telescripting adds an overarching layer of regulation to size-function-stratified genomes, leveraged by selective intron expansion to rapidly shift gene expression priorities.
Asunto(s)
Regulación de la Expresión Génica , Genoma Humano , Poliadenilación , Ribonucleoproteína Nuclear Pequeña U1/metabolismo , Transcripción Genética , HumanosRESUMEN
Accumulation of misfolded proteins in the endoplasmic reticulum (ER) induces the stress response to protect cells against toxicity by the unfolded protein response (UPR), heat shock response (HSR), and ER-associated degradation pathways. Here, we found that over-production of C-terminally truncated multi-transmembrane (MTM) mutant proteins triggers HSR, but not UPR, and clearance of yeast prions [PSI(+)] and [URE3]. One of the mutant MTM proteins, Dip5ΔC-v82, produces a disabled amino-acid permease. Fluorescence microscopy analysis revealed abnormal accumulation of Dip5ΔC-v82 in the ER. Importantly, the mutant defective in the GET pathway, which functions for ER membrane insertion of tail-anchored proteins, failed to translocate Dip5ΔC-v82 to the ER and disabled Dip5ΔC-v82-mediated prion clearance. These findings suggest that the GET pathway plays a pivotal role in quality assurance of MTM proteins, and entraps misfolded MTM proteins into ER compartments, leading to loss-of-prion through a yet undefined mechanism.
Asunto(s)
Degradación Asociada con el Retículo Endoplásmico/fisiología , Factores de Terminación de Péptidos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Transducción de Señal/fisiología , Respuesta de Proteína Desplegada/fisiología , Levaduras/metabolismo , Electroforesis en Gel de Poliacrilamida , Retículo Endoplásmico/metabolismo , Glutatión Peroxidasa/metabolismo , Respuesta al Choque Térmico/fisiología , Proteínas de la Membrana/metabolismo , Microscopía Fluorescente , Plásmidos , Reacción en Cadena de la Polimerasa , Priones/metabolismoRESUMEN
The cytoplasmic [PSI+] element of budding yeast represents the prion conformation of translation release factor eRF-3 (Sup35). Prions are transmissible agents caused by self-seeded highly ordered aggregates (amyloids). Much interest lies in understanding how prions are developed and transmitted. However, the cellular mechanism involved in the prion clearance is unknown. Recently we have reported that excess misfolded multi-transmembrane protein, Dip5ΔC-v82, eliminates yeast prion [PSI+]. In this study, we showed that the prion loss was caused by enlargement of prion amyloids, unsuitable for transmission, and its efficiency was affected by the cellular balance between the chaperone Hsp70-Ssa1 and Sgt2, a small cochaperone known as a regulator of chaperone targeting to different types of aggregation-prone proteins. The present findings suggest that Sgt2 is titrated by excess Dip5ΔC-v82, and the shortage of Sgt2 led to non-productive binding of Ssa1 on [PSI+] amyloids. Clearance of prion [PSI+] by the imbalance between Ssa1 and Sgt2 might provide a novel array to regulate the release factor function in yeast.
RESUMEN
A 14-day-old neonate was transferred to our university hospital because of respiratory distress and mild disturbance of consciousness. He had no history of abnormal pregnancy or delivery, but had developed apnea at 6 days old. Thereafter, respiratory distress progressed and his condition deteriorated. On admission to our hospital, several vesicles were found on the left upper arm, and moderate hepatomegaly was also present. Herpes simplex virus (HSV) type II genome was detected from serum, spinal fluid, and bone marrow. Laboratory examinations revealed typical abnormalities of disseminated intravascular coagulation, increased levels of serum ferritin, aspartate aminotransferase, and lactate dehydrogenase. Bone marrow aspiration demonstrated activated macrophages and hemophagocytosis. Spinal tap revealed numerous mononuclear cells. Meningitis and virus-associated hemophagocytic syndrome (VAHS) due to systemic HSV type II infection were thus diagnosed. Acyclovir (60 mg/kg/day) and vidarabine were promptly administered. Dexamethasone palmitate and intravenous cyclosporine were also administered for systemic inflammation due to VAHS. Finally, these aggressive therapies rescued the patient without any sequelae. In general, neonatal systemic HSV infection is life-threatening and results in poor intact survival. Our case report suggests that not only antiviral treatment for HSV, but also anti-inflammatory treatment including steroid and cyclosporine should be considered from the early phase of neonatal systemic HSV infection.
Asunto(s)
Herpes Simple/complicaciones , Herpesvirus Humano 2 , Linfohistiocitosis Hemofagocítica/complicaciones , Meningitis/complicaciones , Herpes Simple/terapia , Humanos , Recién Nacido , Linfohistiocitosis Hemofagocítica/terapia , Linfohistiocitosis Hemofagocítica/virología , Masculino , Meningitis/terapiaRESUMEN
OBJECTIVE: Patients with Parkinson's disease (PD) lose body weight primarily due to decreased body fat mass. The purpose of this study was to elucidate possible factors related to reduction in the intra-abdominal fat mass of 6-hydroxydopamine (6-OHDA)-treated rats, which are frequently used as an animal model for PD. METHODS: Sham-operated (NPD: n = 4) and unilaterally 6-OHDA-injected (PD: n = 4) 14-wk-old male Sprague-Dawley rats were fed a relatively high-fat diet for 2 wk, during which food intake and body weight were measured. After the 2-wk feeding period, intra-abdominal fat was dissected out and weighed. Carbohydrate and fat absorption-related gene expressions in the jejunum and serum insulin and glucose concentrations were analyzed. RESULTS: Although final body weights did not differ, total intra-abdominal fat weight, expressed relative to body weight, was significantly lower in the PD group than in the NPD group (P < 0.05). There were no significant differences between the two groups in the mRNA expression of carbohydrate and fat digestion/absorption-related genes in the jejunum, or in fat absorption efficacy assessed by fecal fat excretion. However, PD rats showed significantly lower serum insulin and higher glucose concentrations than NPD rats (P < 0.05). CONCLUSION: PD model rats displayed loss of intra-abdominal fat, similar to the progressive loss of fat in PD patients. Our results provide preliminary evidence that reduced lipogenesis due to lower insulin levels, rather than impaired digestion/absorption, might have been involved in this decrease in intra-abdominal fat mass.
Asunto(s)
Insulina/sangre , Grasa Intraabdominal/metabolismo , Oxidopamina/farmacología , Enfermedad de Parkinson/metabolismo , Animales , Peso Corporal , Digestión , Modelos Animales de Enfermedad , Lipogénesis , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
In contrast to the consumption of long-chain triacylglycerols (LCT), consumption of medium- and long-chain triacylglycerols (MLCT) reduces the body fat and blood triacylglycerols (TAG) level in hypertriacylglycerolemic Chinese individuals. These responses may be affected by BMI because of obesity-induced insulin resistance. We aimed to compare the effects of consuming MLCT or LCT on reducing body fat and blood TAG level in hypertriacylglycerolemic Chinese subjects with different ranges of BMI. Employing a double-blind, randomized and controlled protocol, 101 hypertriacylglycerolemic subjects (including 67 men and 34 women) were randomly allocated to ingest 25-30 g/day MLCT or LCT oil as the only cooking oil for 8 consecutive weeks. Anthropometric measurements of body weight, BMI, body fat, WC, HC, blood biochemical variables, and subcutaneous fat area and visceral fat area in the abdomen were measured at week 0 and 8. As compared to subjects with BMI 24-28 kg/m(2) in the LCT group, corresponding subjects in the MLCT group showed significantly greater decrease in body weight, BMI, body fat, WC, ratio of WC to HC, total fat area and subcutaneous fat area in the abdomen, as well as blood TAG and LDL-C levels at week 8. Based upon our results, consumption of MLCT oil may reduce body weight, body fat, and blood TAG and LDL-C levels in overweight hypertriacylglycerolemic Chinese subjects but may not induce these changes in normal or obese hypertriacylglycerolemic subjects.