Relationship between vitiligo and Hashimoto's thyroiditis / Relação entre vitiligo e tireoidite de Hashimoto

Introduction: vitiligo is a multifactorial acquired depigmenting disorder, characterized by a spontaneous loss of functional melanocytes from the epidermis. Vitiligo and Hashimoto's thyroiditis (HT) often occur in association and seem to be characterized by an autoimmune process. The vitiligo associated with HT suggests genetic homologies between them. Objective: to identify protein sequence homology between melanocyte protein (Pmel) and thyroid peroxidase (TPO), using bioinformatics tools, to propose an initial mechanism which could explain the production of cross-reacting autoantibodies to melanocyte and TPO. Methods: we performed a comparison between Pmel and TPO amino acids (AA) sequences, available on the National Center for Biotechnology Information (NCBI) database by BLAST (Basic Local Alignment Search Tool) in order to find local homology regions between the AA sequences. Results: the homology sequence between the Pmel and TPO ranged from 21.0 % (19 identical residues out of 90 AA in the sequence) to 55.0% (6 identical residues out of 11 AA in the sequence). The identical alignments presented relatively high E values due to presence of short alignment. Conclusion: bioinformatics data suggest a possible pathological link between Pmel and TPO. Sequence homology between Pmel and TPO may present a molecular mimicry suggesting the possibility of antigen crossover between Pmel and TPO that might represent an immunological basis for vitiligo associated with HT.

Introdução: o vitiligo é uma doença de despimentação adquirida multifatorial, caracterizada por uma perda espontânea de melanócitos funcionais da epiderme. Vitiligo e tiroidite de Hashimoto (TH) ocorrem frequentemente em associação e parecem ser caracterizados por um processo autoimune. O vitiligo associado à TH sugere homologias genéticas entre eles. Objetivo: identificar homologia das sequências de proteína entre a proteína do melanócito (Pmel) e peroxidase da tiróide (TPO), usando ferramentas de bioinformática, para propor um mecanismo inicial que poderia explicar a produção de autoanticorpos de reação cruzada entre o melanócito e a TPO. Metodologia: foi realizada uma comparação entre a sequência de aminoácidos (AA) da Pmel e da TPO, disponível no banco de dados Basic Local Alignment Search Tool (BLAST) do National Center for Biotechnology Information (NCBI), a fim de encontrar regiões de homologia locais entre as sequências de AA. Resultados: a sequência de homologia entre a Pmel e a TPO variou de 21,0% (19 resíduos idênticos na sequência de cada 90 AA na sequência) a 55,0% (6 resíduos idênticos na sequência de 11 AA). Os alinhamentos idênticos apresentaram valores relativamente altos (E) devido à presença de alinhamentos curtos. Conclusão: os dados de Bioinformática sugerem uma possível ligação patológica entre Pmel e a TPO. A sequência de homologia entre Pmel e a TPO pode apresentar um mimetismo molecular sugerindo a possibilidade de cruzamento entre antígeno da Pmel e da TPO que pode representar uma base imunológica para a associação entre o vitiligo e a TH.

Evolutionary characteristics of envelope glycoproteins in Ebora virus / 中华临床感染病杂志

Objective To study the evolutionary and mutant characteristics of Ebora virus envelope glycoprotein.Methods A total of 100 Ebora virus envelope glycoproteins amino acid sequences isolated during 1976 and 2014 were collected from National Center for Biotechnology Information (NCBI).Multiple sequence alignment and phylogenetic tree analysis were performed to investigate the evolutionary and mutant characteristics of Ebora virus envelope glycoprotein.Results Glycoprotein amino acid sequences of Ebora virus isolated during 1976 and 2014 showed only 54.00％-65.00％ homology among different subtypes,while 95.00％-100.00％ homology in same subtypes.Ebola virus isolated from different regions in 2014 showed a 99.70％-100.00％ homology of glycoprotein amino acid sequences in the same subtype.The homology of glycoprotein amino acid sequences of Ebola-Zaire virus isolated from Sierra Leone in 2014 was 100.00％,but three strains of Ebola-Zaire virus isolated from Guinea showed diversity in glycoprotein amino acid sequences.Glycoprotein amino acid sequences of Ebola virus with different subtypes were on different branches of phylogenetic tree.Glycoprotein amino acid sequences of Ebola-Zaire virus isolated from Sierra Leone in 2014 were on one branch,and those of Ebola-Zaire virus isolated from other countries during 1976 and 2014 were on the another branch.Conclusions Glycoprotein amino acid sequences of Ebora virus vary with time and region.Ebola-Zaire virus isolated from different regions in 2014 may be two variants with the same origin,and hybrid phenomenon is not observed among virus of different subtypes.