RESUMO
Antimicrobial peptides (AMPs) are mainly produced by epithelial cells and macrophages to eliminate infecting mycobacteria through direct antimicrobial activity and immunomodulation. Indeed, it has been described that this line of defense is essential to control infection. However, Mycobacterium tuberculosis (Mtb) has developed mechanisms to avoid AMPs activity, for instance lysX adds lysine residues to surface phospholipids changing their net charge, leading to the repelling of the AMPs. In the present study, we determined that lysX gene is differentially expressed among Mtb strains. To achieve this aim we used several well-characterized Mtb clinical isolates, lysX mutated strains and reference strains. Our results showed that in the presence of AMPs, lysX expression increased significantly. Strains with higher lysX expression showed increased levels of intracellular survival in vivo and in vitro and induced more severe lesion related with pneumonia. Results showed that ability of Mtb to replicate intracellularly was directly correlated to the level of lysX expression showing that the amount of lysX produced by the bacterial cell is an important variable for the modulation of Mtb virulence.
Assuntos
Proteínas de Bactérias/genética , Lisina-tRNA Ligase/genética , Mutação , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/patogenicidade , Tuberculose Pulmonar/microbiologia , Células A549 , Animais , Peptídeos Catiônicos Antimicrobianos , Antituberculosos/farmacologia , Proteínas de Bactérias/metabolismo , Catelicidinas/genética , Catelicidinas/metabolismo , Catelicidinas/farmacologia , Modelos Animais de Doenças , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Regulação Bacteriana da Expressão Gênica , Genótipo , Interações Hospedeiro-Patógeno , Humanos , Pulmão/metabolismo , Pulmão/microbiologia , Lisina-tRNA Ligase/metabolismo , Macrófagos/metabolismo , Macrófagos/microbiologia , Camundongos Endogâmicos BALB C , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/crescimento & desenvolvimento , Fagocitose , Fenótipo , Tuberculose Pulmonar/tratamento farmacológico , Tuberculose Pulmonar/metabolismo , Virulência , beta-Defensinas/genética , beta-Defensinas/metabolismoRESUMO
Aging is a major health issue due to the increased susceptibility of elderly people to infectious, autoimmune, and cardiovascular diseases. Innate immunity is an important mechanism to avoid primary infections; therefore, decreasing of its activity may lead to development of infections. Antimicrobial peptides (AMPs) are effector molecules of innate immunity that can eliminate microbial invaders. The role that cytokines play in the regulation of these innate immune mechanisms needs to be explored. Serum determinations of Th1, Th2, and Th17 cytokines were performed in order to evaluate their association with AMPs human beta-defensin (HBD)-2 and LL-37 in young adults, elder adults, and elder adults with recurrent infections. Our results showed differences in interleukin (IL)-10 and IL-6 among the different groups. Inverse correlations in serum cytokine levels and HBD-2 production were identified for IL-10, IL-2, IL-4, tumor necrosis factor-α, and IL-6. Also inverse correlations were identified for IL-10, IL-4, and cathelicidin (LL-37). Such results could impact the development of immunomodulators that promote AMP production to prevent and/or contain infectious diseases in this population.
Assuntos
Envelhecimento/imunologia , Peptídeos Catiônicos Antimicrobianos/metabolismo , Infecções/imunologia , Células Th1/imunologia , Células Th17/imunologia , Células Th2/imunologia , beta-Defensinas/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Peptídeos Catiônicos Antimicrobianos/sangue , Células Cultivadas , Citocinas/metabolismo , Humanos , Imunidade Inata , Pessoa de Meia-Idade , Recidiva , Adulto Jovem , CatelicidinasRESUMO
Diabetes mellitus (DM)-2 patients have an increased susceptibility to develop pulmonary tuberculosis; this is partly due to the impairment of the innate immunity because of their higher glucose concentrations. In the present study, we determined the effect of the glucose concentrations in the LL-37 expression in infected and non-infected macrophages. Our results showed that the increasing glucose concentrations correlates with the low cathelicidin expression in non-infected cells, however in Mycobacterium tuberculosis infected cells, LL-37 expression was substantially increased in higher glucose concentrations, nevertheless the mycobacterial burden also increased, this phenomena can be associated with the cathelicidin immunomodulatory activity. Further evaluation for LL-37 needs to be done to determine whether this peptide can be used as a biomarker of tuberculosis progression in DM2 patients.
Assuntos
Peptídeos Catiônicos Antimicrobianos/metabolismo , Glucose/metabolismo , Macrófagos/imunologia , Mycobacterium tuberculosis/imunologia , Carga Bacteriana , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Células U937 , CatelicidinasRESUMO
Tuberculosis is one of the most important infectious diseases worldwide. The susceptibility to this disease depends to a great extent on the innate immune response against mycobacteria. Host defense peptides (HDP) are one of the first barriers to counteract infection. Cathelicidin (LL-37) is an HDP that has many immunomodulatory effects besides its weak antimicrobial activity. Despite advances in the study of the innate immune response in tuberculosis, the immunological role of LL-37 during M. tuberculosis infection has not been clarified. Monocyte-derived macrophages were infected with M. tuberculosis strain H37Rv and then treated with 1, 5, or 15 µg/ml of exogenous LL-37 for 4, 8, and 24 h. Exogenous LL-37 decreased tumor necrosis factor alpha (TNF-α) and interleukin-17 (IL-17) while inducing anti-inflammatory IL-10 and transforming growth factor ß (TGF-ß) production. Interestingly, the decreased production of anti-inflammatory cytokines did not reduce antimycobacterial activity. These results are consistent with the concept that LL-37 can modulate the expression of cytokines during mycobacterial infection and this activity was independent of the P2X7 receptor. Thus, LL-37 modulates the response of macrophages during infection, controlling the expression of proinflammatory and anti-inflammatory cytokines.
Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Fatores Imunológicos/farmacologia , Macrófagos/efeitos dos fármacos , Mycobacterium tuberculosis/efeitos dos fármacos , Linhagem Celular , Relação Dose-Resposta Imunológica , Expressão Gênica , Humanos , Imunidade Inata , Interleucina-10/genética , Interleucina-10/imunologia , Interleucina-17/genética , Interleucina-17/imunologia , Macrófagos/imunologia , Macrófagos/microbiologia , Mycobacterium tuberculosis/crescimento & desenvolvimento , Mycobacterium tuberculosis/imunologia , Fagocitose/efeitos dos fármacos , Cultura Primária de Células , Receptores Purinérgicos P2X7/genética , Receptores Purinérgicos P2X7/imunologia , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/imunologia , CatelicidinasRESUMO
Diabetic foot ulcers (DFU) are one of the most common diabetes-related cause of hospitalization and often lead to severe infections and poor healing. It has been recently reported that patients with DFU have lower levels of antimicrobial peptides (AMPs) at the lesion area, which contributes with the impairment of wound healing. The aim of this study was to determine whether 1,25-dihydroxyvitamin D3 (1,25 (OH)2 D3) and L-isoleucine induced HBD-2 and LL-37 in primary cultures from DFU. We developed primary cell cultures from skin biopsies from 15 patients with DFU and 15 from healthy donors. Cultures were treated with 1,25 (OH)2D3 or L-isoleucine for 18 h. Keratinocytes phenotype was identified by western blot and flow cytometry. Real time qPCR for DEFB4, CAMP and VDR gene expression was performed as well as an ELISA to measure HBD-2 and LL-37 in supernatant. Antimicrobial activity, in vitro, wound healing and proliferation assays were performed with conditioned supernatant. The results show that primary culture from DFU treated with 1,25(OH)2D3, increased DEFB4 and CAMP gene expression and increased the production of HBD-2 and LL-37 in the culture supernatant. These supernatants had antimicrobial activity over E. coli and induced remarkable keratinocyte migration. In conclusion the 1,25(OH)2D3 restored the production of AMPs in primary cell from DFU which were capable to improve the in vitro wound healing assays, suggesting their potential therapeutic use on the treatment of DFU.
Assuntos
Catelicidinas/biossíntese , Pé Diabético/metabolismo , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Vitamina D/análogos & derivados , beta-Defensinas/biossíntese , Adulto , Idoso , Idoso de 80 Anos ou mais , Peptídeos Catiônicos Antimicrobianos/biossíntese , Peptídeos Catiônicos Antimicrobianos/genética , Biópsia , Estudos de Casos e Controles , Catelicidinas/genética , Movimento Celular/efeitos dos fármacos , Proliferação de Células , Células Cultivadas , Meios de Cultivo Condicionados , Pé Diabético/diagnóstico , Pé Diabético/genética , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Fenótipo , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo , Vitamina D/farmacologia , Cicatrização , beta-Defensinas/genéticaRESUMO
The increasing number of people with type 2 diabetes (DM2) is alarming and if it is taken into account that the relative odds of developing tuberculosis in diabetic patients ranges from 2.44 to 8.33 compared with non-diabetic patients, thus in developing countries where these two diseases are encountering face to face, there is a need for prophylaxis strategies. The role of vitamin D has been widely implicated in growth control of Mycobacterium tuberculosis (Mtb) during primary infection mainly through the induction of certain antimicrobial peptides (AMPs). In this study we evaluated the vitamin D serum levels, CYP27B1-hydroxylase enzyme, vitamin D receptor (VDR) and AMPs gene expression in Healthy donors, DM2 and TB patients. Results showed that DM2 group has lower VDR and AMPs expression levels. When Monocytes Derived Macrophages (MDM) from DM2 patients with low VDR expression were supplemented with vitamin D, MDMs eliminate efficiently M. tuberculosis. This preliminary study suggests the use of vitamin D as prophylaxis for tuberculosis in high DM2 endemic countries.