RESUMO
Post-transcriptional modifications are added to ribosomal RNAs (rRNAs) to govern ribosome biogenesis and to fine-tune protein biosynthesis. In Escherichia coli and related bacteria, RlhA uniquely catalyzes formation of a 5-hydroxycytidine (ho5C) at position 2501 of 23S rRNA. However, the molecular and biological functions as well as the regulation of ho5C2501 modification remain unclear. We measured growth curves with the modification-deficient ΔrlhA strain and quantified the extent of the modification during different conditions by mass spectrometry and reverse transcription. The levels of ho5C2501 in E. coli ribosomes turned out to be highly dynamic and growth phase-dependent, with the most effective hydroxylation yields observed in the stationary phase. We demonstrated a direct effect of ho5C2501 on translation efficiencies in vitro and in vivo. High ho5C2501 levels reduced protein biosynthesis which however turned out to be beneficial for E. coli for adapting to oxidative stress. This functional advantage was small under optimal conditions or during heat or cold shock, but becomes pronounced in the presence of hydrogen peroxide. Taken together, these data provided first functional insights into the role of this unique 23S rRNA modification for ribosome functions and bacterial growth under oxidative stress.
Assuntos
Proteínas de Escherichia coli/metabolismo , Escherichia coli/genética , RNA Bacteriano/metabolismo , RNA Ribossômico 23S/metabolismo , Ribossomos/metabolismo , Estresse Oxidativo , Processamento Pós-Transcricional do RNARESUMO
The present study aimed to investigate how playing positions differ in specific body composition variables in professional soccer players with respect to specific field zones and tactical lines. Five hundred and six Serie A and B professional soccer players were included in the study and analyzed according to their playing positions: goalkeepers (GKs), central backs (CBs), fullbacks (FBs), central midfielders (MIDs), wide midfielders (WMs), attacking midfielders (AMs), second strikers (SSs), external strikers (ESs), and central forwards (CFs), as well as their field zones (central and external) and tactical lines (defensive, middle, and offensive). Anthropometrics (stature and body mass) of each player were recorded. Then, body composition was obtained by means of bioelectric impedance analysis (BIA). GKs and CFs were the tallest and heaviest players, with no differences from each other. Likewise, GKs and CFs, along with CBs, were apparently more muscular (for both upper and lower limbs) and fatter at the same time compared with the other roles. Overall, players of the defensive line (CBs and FBs), along with those playing in central field zones (CBs, MIDs, AMs, SSs, and CFs), were significantly (p < 0.05) superior in almost all anthropometric and body composition variables than those of middle and offensive line and external zones, respectively.
RESUMO
The importance of non-coding RNAs for regulating gene expression has been uncovered in model systems spanning all three domains of life. More recently, their involvement in modulating signal transduction, cell proliferation, tumorigenesis and cancer progression has also made them promising tools and targets for oncotherapy. Recent studies revealed a class of highly conserved small ncRNAs, namely vault RNAs, as regulators of several cellular homeostasis mechanisms. The human genome encodes four vault RNA paralogs that share significant sequence and structural similarities, yet they seem to possess distinct roles in mammalian cells. The alteration of vault RNA expression levels has frequently been observed in cancer tissues, thus hinting at a putative role in orchestrating pro-survival characteristics. Over the last decade, significant advances have been achieved in clarifying the relationship between vault RNA and cellular mechanisms involved in cancer development. It became increasingly clear that vault RNAs are involved in controlling apoptosis, lysosome biogenesis and function, as well as autophagy in several malignant cell lines, most likely by modulating signaling pathways (e.g., the pro-survival MAPK cascade). In this review, we discuss the identified and known functions of the human vault RNAs in the context of cell proliferation, tumorigenesis and chemotherapy resistance.
RESUMO
The small non-coding VTRNA1-1 (vault RNA 1-1) is known to confer resistance to apoptosis in several malignant cell lines and to also modulate the macroautophagic/autophagic flux in hepatocytes, thus highlighting its pro-survival role. Here we describe a new function of VTRNA1-1 in regulating in vitro and in vivo tumor cell proliferation, tumorigenesis and chemoresistance. Knockout (KO) of VTRNA1-1 in human hepatocellular carcinoma cells reduced nuclear localization of TFEB (transcription factor EB), leading to a downregulation of the coordinated lysosomal expression and regulation (CLEAR) network genes and lysosomal compartment dysfunction. We demonstrate further that impaired lysosome function due to loss of VTRNA1-1 potentiates the anticancer effect of conventional chemotherapeutic drugs. Finally, loss of VTRNA1-1 reduced drug lysosomotropism allowing higher intracellular compound availability and thereby significantly reducing tumor cell proliferation in vitro and in vivo. These findings reveal a so far unknown role of VTRNA1-1 in the intracellular catabolic compartment and describe its contribution to lysosome-mediated chemotherapy resistance.Abbreviations: ATP6V0D2: ATPase H+ transporting V0 subunit d2; BafA: bafilomycin A1; CLEAR: coordinated lysosomal expression and regulation; CQ: chloroquine; DMSO: dimethyl sulfoxide; GST-BHMT: glutathionine S-transferase N-terminal to betaine-homocysteine S-methyltransferase; HCC: hepatocellular carcinoma; LAMP1: lysosomal associated membrane protein 1; LLOMe: L-leucyl-L-leucine methyl ester; MAP1LC3B/LC3: microtubule associated protein 1 light chain 3 beta; MAPK: mitogen-activated protein kinase; MITF: melanocyte inducing transcription factor; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; ncRNA: non-coding RNA; RNP: ribonucleoprotein; SF: sorafenib; SQSTM1/p62: sequestosome 1; STS: staurosporine; tdRs: tRNA-derived RNAs; TFE3: transcription factor binding to IGHM enhancer 3; TFEB: transcription factor EB; vtRNA: vault RNA transcript.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Autofagia , Carcinogênese/genética , Carcinogênese/metabolismo , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Lisossomos/metabolismo , RNA/metabolismoRESUMO
Prevalence, clinical correlates, and use of glucose-lowering drugs were comprehensively evaluated among 863 nursing home older patients with diabetes (mean age 82.9 ± 2.1 years): functional dependence and cognitive impairment were present in 84.1% and 68% of patients, respectively, and 66.3% of patients had 2-4 comorbidities. HbA1c values < 7.0% were documented in 54.9% of diabetic; significantly lower HbA1c levels were observed in demented patients than in nondemented subjects. Documented hypoglycemic episodes were reported for 57 patients (6.6%), without significant association with age, functional dependence, cognitive impairment, or HbA1c levels. About one-fifth of older long-term facilities residents have diabetes, with concomitant poor health conditions and high prevalence of cognitive impairment and functional dependence. Roughly three-fourths of these older and frail diabetic patients have HbA1c values lower than optimal, suggesting a potential for hypoglycemic harm especially among patients with severe cognitive impairment.
Assuntos
Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Assistência de Longa Duração , Idoso de 80 Anos ou mais , Envelhecimento , Glicemia/análise , Índice de Massa Corporal , Transtornos Cognitivos/sangue , Demência/complicações , Diabetes Mellitus Tipo 2/epidemiologia , Feminino , Idoso Fragilizado , Hemoglobinas Glicadas/metabolismo , Humanos , Hipoglicemia/sangue , Masculino , Prevalência , Estudos ProspectivosRESUMO
The aim of the present study was to evaluate the possible association between occurrence of soft tissue sarcomas in Verona (Italy) and residence near a steel foundry, whose emissions of dioxin-like compounds may be relevant. Exposure to total suspended particulate (TSP) emitted from the plant as estimated by ADMS-urban dispersion model was used as an indirect index of exposure to dioxin-like compounds. Verona municipality was divided in six subareas according to the decreasing levels of estimated TSP exposure, and soft tissue sarcomas cases were mapped according to residence at time of diagnosis. Standardized incidence ratios were computed. No statistically significant departures between observed and expected cases were detected as illustrated by trend-test results.