ABSTRACT
Resumen Los microRNA (miRNA) son pequeños RNA no codificantes de aproximadamente 17 a 24 nucleótidos de longitud, los cuales se unen complementaria y principalmente en las regiones 3' UTR (región no traducida) de diversos RNA mensajeros (mRNA, messenger RNA). Su función general es regular negativamente la expresión génica a nivel postranscripcional, inhibiendo la traducción. Perfiles de expresión de miRNA alterados han sido identificados en diferentes líquidos, células y tejidos humanos afectados con diversas enfermedades autoinmunes y algunos se han propuestos potencialmente como biomarcadores de diagnóstico, pronóstico, actividad, etcétera, en estas patologías. Adicionalmente, variantes comunes del genoma humano, denominados polimorfismos de un solo nucleótido (SNP, single nucleotide polymorphisms) localizados en genes de miRNA han sido asociados con susceptibilidad, gravedad, y actividad en estas enfermedades. El objetivo de esta revisión es describir la biogénesis de los miRNA, su función, así como los perfiles de expresión y SNP en genes de miRNA asociados con diversas enfermedades autoinmunes, incluyendo tiroiditis autoinmune (tiroiditis de Hashimoto y enfermedad de Graves), lupus eritematoso sistémico, artritis reumatoide y síndrome de Sjögren primario.
Abstract MicroRNAs (miRNAs) are small non-coding RNAs of approximately 17-24 nucleotides in length, which complementarily and mainly bind in 3' UTR (untranslated region) regions of different messenger RNAs (mRNAs). Their general function is to negatively regulate gene expression at the posttranscriptional level, thus inhibiting translation. miRNA abnormal expression profiles of have been found in different human fluids, cells and tissues affected by different autoimmune diseases, and some of them have been proposed as potential biomarkers of diagnosis, prognosis, activity etc. in these pathologies. In addition, common variants of the human genome, called single-nucleotide polymorphisms (SNPs), located within miRNA genes, have been associated with susceptibility, severity and activity in these diseases. The purpose of this review is to describe miRNA biogenesis and function, as well as the expression profiles and SNPs in miRNA genes that are associated with different autoimmune diseases, including autoimmune thyroiditis (HashimotoMs thyroiditis and Gravess disease), systemic lupus erythematosus, rheumatoid arthritis and primary Sjögren's syndrome.
Subject(s)
Humans , Autoimmune Diseases/genetics , Gene Expression Regulation , MicroRNAs/genetics , Autoimmune Diseases/physiopathology , Autoimmune Diseases/immunology , Severity of Illness Index , Polymorphism, Single NucleotideABSTRACT
OBJECTIVE: To evaluate cytology laboratories and the performance of cytotechnologists for establishing efficient external quality control for Mexico's National Program for the Prevention and Control of Cervical Cancer. MATERIAL AND METHODS: During January and February 1998, an onsite evaluation of all cytology laboratories of the Ministry of Health found that only 70 of the microscopes were in adequate working conditions, reagents were out of date, and working conditions were sub-optimal. A program for external quality control based on proficiency testing was established for cytotechnologists. Fifty slide sets with 20 Papanicolaou slides and 10 photographic slides were prepared. The sets were given to the cytotechnologists for evaluation and again one year later by courier. RESULTS: Twenty-one percent of microscopes were repaired and 9 replaced; reagents were distributed and laboratory facilities improved. Only 16 of cytotechnologists passed the initial proficiency test. Cytotechnologists received a refresher training course: one year later 67 of them passed the proficiency test. To ascertain that each slide was correctly diagnosed, 41 sets were rescreened by expert cytopathologists or cytologists and their diagnoses compared to the original ones. Thirty-seven sets had 86 to 96 concordance. CONCLUSIONS: This new system for external quality control of cervical cytology allowed the opportune and reliable evaluation of the performance of cytotechnologists.