Micronutrients influencing the immune response in leprosy / Micronutrientes que influyen en la respuesta immune en la lepra

La lepra es una enfermedad infecciosa crónica causada por el Mycobacterium leprae, un bacilo intracelular de transmisión aérea. La enfermedad afecta la piel y los nervios periféricos y causa secuelas neurológicas. El bacilo se multiplica lentamente en el hospedador y posiblemente la enfermedad ocurre por el mal funcionamiento de la respuesta inmunitaria del hospedador. Esta revisión aborda el papel de algunos micronutrientes específicos en la respuesta inmunitaria, tales como las vitaminas A, D, E, C, el cinc y el selenio, detallando sus mecanismos de acción en las enfermedades infecciosas y en la lepra. La respuesta inmunitaria a los patógenos libera sustancias nocivas que producen lesión tisular. Esta revisión también aborda cómo una menor cantidad de antioxidantes puede contribuir a un aumento del estrés oxidativo y a complicaciones de las enfermedades infecciosas y la lepra. Puesto que los micronutrientes poseen un efecto regulador de la respuesta inmunitaria innata y adaptativa, es importante un equilibrio perfecto de sus concentraciones para mejorar la respuesta inmunitaria frente a los patógenos (AU)

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, an intracellular bacillus of airborne transmission. The disease affects the skin and peripheral nerves and can cause neurological sequelae. The bacillusmultiplies slowly in the host and the disease probably occurs due to malfunctioning in host immune response. This review addresses the role of some specific micronutrients in the immune response, such as Vitamins A, D, E, C, Zinc and Selenium, detailing their mechanisms of actions in infectious diseases, and in leprosy. The immune response to pathogens releases harmful substances, which lead to tissue damage. This review discusses how a decreased level of antioxidants may contribute to an increased oxidative stress and complications of infectious diseases and leprosy. As the nutrients have a regulatory effect in the innate and adaptative immune responses, a perfect balance in their concentrations is important to improve the immune response against the pathogens (AU)

Profiling microRNA expression in bovine alveolar macrophages using RNA-seq.

MicroRNAs (miRNAs) are important regulators of gene expression and are known to play a key role in regulating both adaptive and innate immunity. Bovine alveolar macrophages (BAMs) help maintain lung homeostasis and constitute the front line of host defense against several infectious respiratory diseases, such as bovine tuberculosis. Little is known, however, about the role miRNAs play in these cells. In this study, we used a high-throughput sequencing approach, RNA-seq, to determine the expression levels of known and novel miRNAs in unchallenged BAMs isolated from lung lavages of eight different healthy Holstein-Friesian male calves. Approximately 80 million sequence reads were generated from eight BAM miRNA Illumina sequencing libraries, and 80 miRNAs were identified as being expressed in BAMs at a threshold of at least 100 reads per million (RPM). The expression levels of miRNAs varied over a large dynamic range, with a few miRNAs expressed at very high levels (up to 800,000RPM), and the majority lowly expressed. Notably, many of the most highly expressed miRNAs in BAMs have known roles in regulating immunity in other species (e.g. bta-let-7i, bta-miR-21, bta-miR-27, bta-miR-99b, bta-miR-146, bta-miR-147, bta-miR-155 and bta-miR-223). The most highly expressed miRNA in BAMs was miR-21, which has been shown to regulate the expression of antimicrobial peptides in Mycobacterium leprae-infected human monocytes. Furthermore, the predicted target genes of BAM-expressed miRNAs were found to be statistically enriched for roles in innate immunity. In addition to profiling the expression of known miRNAs, the RNA-seq data was also analysed to identify potentially novel bovine miRNAs. One putatively novel bovine miRNA was identified. To the best of our knowledge, this is the first RNA-seq study to profile miRNA expression in BAMs and provides an important reference dataset for investigating the regulatory roles miRNAs play in this important immune cell type.

Innate and acquired immune responses to mycobacterial infections: involvement of IL-17A/IL-23 axis in protective immunity.

Pulmonary tuberculosis is an infectious disease caused by Mycobacterium tuberculosis, and continues to be a serious threat to human life. Since M. tuberculosis establishes intracellular parasitism in macrophages, host innate and acquired immune systems have to detect and enhance bactericidal activity against the intracellular bacteria. Understanding of interaction between pathogenic factors of M. tuberculosis and host is also important to understand how immune system copes with the pathogen. In this review, we shortly summarize the mechanisms how innate and acquired immunity recognize M. tuberculosis or M. tuberculosis-infected cells and protects hosts from the infection. Furthermore, IL-17A/IL-23 axis, a recently focused inflammatory cytokine system, is discussed in the context of anti-mycobacterial protective immunity.