RESUMO
Human papillomavirus (HPV) infection can lead to the development of productive epithelial lesions and cervical cancer. Most cervical HPV infections are solved by cell-mediated immunity within 1-2 years, and it is known that chronic inflammation predisposes to lesions progression and tumour development. In this context, we highlight the CC chemokine receptor 5 (CCR5) which is involved in leucocytes chemotaxis to sites of inflammation, controlling the immune response. The CCR5 rs333 genotyping of 164 HPV infected women and 185 non-infected women was performed using polymerase chain reaction (PCR). HPV infection was more frequent among women under 34 years old (p < 0.001), single (p = 0.001), that received 1 minimum wage or less (p = 0.002), tobacco smokers (p = 0.007), who had the first sexual intercourse before 17 years old (p = 0.038) and that had 4 or more sexual partners during lifetime (p = 0.001). No significant difference regarding genotypes and alleles distribution according to HPV infection was observed. CCR5/CCR5 genotype was observed in 94.1% of HPV non-infected women and in 89% of infected ones, CCR5/Δ32 in 5.9% of HPV infected and in 10.4% of non-infected women, and Δ32/Δ32 was observed in only one (0.6%) infected patient. CCR5 genotypes were also not associated with cervical lesions development among HPV infected women (p = 0.167). Since CCR5 may control the antitumour immune response and cervical lesions and the studied rs333 polymorphism is not very frequent, other studies are necessary, in order to establish CCR5 role on HPV infection and squamous intraepithelial lesions development.
Assuntos
Variação Genética , Infecções por Papillomavirus/complicações , Receptores CCR5/genética , Displasia do Colo do Útero/epidemiologia , Displasia do Colo do Útero/etiologia , Neoplasias do Colo do Útero/epidemiologia , Neoplasias do Colo do Útero/etiologia , Adulto , Idoso , Alelos , Brasil/epidemiologia , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Pessoa de Meia-Idade , Infecções por Papillomavirus/virologia , Polimorfismo Genético , Medição de Risco , Fatores de Risco , Displasia do Colo do Útero/patologia , Neoplasias do Colo do Útero/patologiaRESUMO
A beta-glucosidase-like enzyme-encoding gene (bglH) of an endophytic Bacillus pumilus strain (CL16) was cloned using a shotgun genomic library constructed in Escherichia coli. The nucleotide sequence of the entire cloned fragment (2484 bp) was determined and characterized. An incomplete open reading frame (ORF) of 534 bp (ORF1) designated bglP and a complete ORF of 1419 bp (ORF2) designated bglH, located in the fragment, are organized in an operon. The protein deduced from 1419 bp (ORF2) had 472 amino acid residues without a characteristic signal peptide sequence, suggesting that the enzyme is localized in the cytoplasm. The amino acid sequence deduced from bglH gene had high similarity with beta-glucosidases from the glycosyl hydrolase family 1. Over-expression of the B. pumilus bglH gene in E. coli showed a 54 kDa protein whose identity was confirmed by mass spectrometry (MALDI-TOF).
RESUMO
It has been known for decades that exogenous RNAs are able to induce cytotoxic T lymphocytes (CTLs) and immunological reactivity to a wide variety of antigens. The molecular events responsible for these effects remain unclear for more than two decades. It has been decided to revisit this phenomenon in the light of new concepts that are just emerging in Molecular Biology, such as the regulation of gene expression by noncoding RNAs, named regulatory RNAs. The immunological effects observed in lymphocytes treated with RNAs obtained from lymph nodes of immunized animals with different types of antigens including synthetic peptides of the human immunodeficiency virus type 1 (HIV-1) have been investigated. Our recent results showed that regulatory RNAs are involved in this phenomenon, which is due to the activation of the RNA-dependent protein kinase (PKR) by regulatory RNAs with subsequent activation of the transcription factor NF-kappaB. The RNA-dependent protein kinase (PKR) is a serine/threonine kinase and contains two RNA-binding domains (RBD-I and RBD-II) within the N-terminal region. PKR is activated by viral double-stranded RNA (dsRNA) and highly structured single-stranded RNAs. This review will focus on the structure and functions of PKR including its role in HIV-1 infection. Special emphasis will be placed on a regulatory RNA, named p9-RNA, isolated from lymphocytes of animals immunized with the synthetic peptide p9 (pol: 476-484) of HIV-1. It was found that the regulatory p9-RNA induces CTLs and production of IFN-gamma. These findings showed for the first time that transcriptional control of gene expression by a regulatory RNA can be mediated by PKR through the activation of the transcription factor NF-kappaB. A model for the mechanism of action of the regulatory p9-RNA responsible for the production of IFN-gamma is proposed. Elucidating the molecular mechanism of p9-RNA may contribute to determining the rationale for the use of this regulatory RNA as an immunomodulator in HIV-infected patients.
Assuntos
Infecções por HIV/imunologia , Linfócitos/enzimologia , Linfócitos/imunologia , RNA não Traduzido/fisiologia , eIF-2 Quinase/metabolismo , Animais , Humanos , Linfócitos/metabolismo , RNA , eIF-2 Quinase/químicaRESUMO
Previous results with p9-RNA, obtained from lymph nodes of animals immunized with the peptide p9 of HIV-1, suggested that its effects on lymphocytes could be mediated by RNA-dependent protein kinase (PKR). Here we report that p9-RNA activates PKR leading to the degradation of the inhibitor I-kappaB alpha and the concomitant nuclear factor kappa B (NF-kappaB) activation. The fractionation of p9-RNA by affinity chromatography indicates that the poly A(+) p9-RNA is the fraction responsible for PKR activation. We also found that p9-RNA induces the production of interferon-gamma (IFN-gamma), but not interleukin (IL-4) since only IFN-gamma gene promoter contains NF-kappaB binding site. This study provides the first evidence that transcriptional control of gene expression by regulatory RNAs can be mediated by PKR through NF-kappaB activation. A model for the mechanism of action of poly A(+) p9-RNA is proposed.
Assuntos
Interferon gama/metabolismo , Interleucina-4/metabolismo , Linfócitos/metabolismo , NF-kappa B/fisiologia , RNA/metabolismo , eIF-2 Quinase/fisiologia , Sequência de Aminoácidos , Animais , Células Cultivadas , Feminino , Humanos , Proteínas I-kappa B/efeitos dos fármacos , Proteínas I-kappa B/metabolismo , Interferon gama/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , NF-kappa B/efeitos dos fármacos , Poli A , RNA/farmacologia , Proteínas Virais/genética , eIF-2 Quinase/efeitos dos fármacosRESUMO
Exogenous RNA molecules can be incorporated into eukaryotic cells and can exert a variety of biological effects. We have previously showed that exogenous RNAs obtained from lymphoid organs of animals immunized with synthetic peptides of HIV-1 are able to induce cell-mediated immune responses. In this study, animals were immunized with a synthetic peptide (pol: 476-484) of HIV-1, referred to as p9, which is a cytotoxic T lymphocyte (CTL) epitope. The RNA extracted from the lymphoid organs of animals immunized with p9 was termed p9-RNA. We have demonstrated that p9-RNA is active in inducing human CTL. The p9-RNA was also able to activate the RNA-dependent protein kinase (PKR) of human lymphocytes. The polyA(+) p9-RNA was the fraction responsible for the activation of this protein kinase. We also found that p9-RNA activates the transcription factor nuclear kappa B (NF-kappaB) by inducing the degradation of its inhibitor I-kappaB. Thus, these findings suggest that p9-RNA may act as a regulatory RNA and that the induction of CTL activity by p9-RNA could be mediated by PKR through NF-kappaB activation. It is known that CTL activity plays an important role in host defense against HIV-1 infection. Elucidating the molecular mechanism of p9-RNA could contribute to determining the basis for the use of p9-RNA as an immunomodulator in HIV-infected patients.
Assuntos
Antígenos HIV/imunologia , RNA/imunologia , Linfócitos T Citotóxicos/enzimologia , Linfócitos T Citotóxicos/imunologia , eIF-2 Quinase/metabolismo , Animais , Western Blotting , Ativação Enzimática , Epitopos de Linfócito T/imunologia , Cobaias , Humanos , Camundongos , Camundongos Endogâmicos , NF-kappa B/metabolismo , Peptídeos/síntese química , Peptídeos/imunologia , Fosforilação , RNA/isolamento & purificaçãoRESUMO
Our previous results showed that L-RNA, extracted from lipopolysaccharide-stimulated macrophages, induces interleukin-1, interleukin-8 and tumor necrosis factor-alpha (TNF-alpha) in resident macrophages. It was demonstrated the promoter of these cytokine genes contain nuclear factor-kB (NF-kappa B) binding sites. We hypothesized that this effect of L-RNA is mediated by RNA-dependent protein kinase (PKR) through NF-kappa B activation. We found that L-RNA activates PKR and induces NF-kappa B activation through degradation of its inhibitor I-kappa B alpha. These data support the idea that L-RNA acts as a regulatory RNA. A model for the mechanism of action of L-RNA is proposed.