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Iron (Fe) homeostasis control is important for both pathogen and the host. During infection, the host reduces the access of microorganisms to iron, however, studies have shown that virulent pathogens are capable to sequester Fe from host proteins, and establish the infection. M. abscessus subsp. massiliense (Mycma), that is resistant to most drugs used against tuberculosis, was responsible for outbreaks around the world showing increased virulence when compared to other rapidly growing mycobacteria. The goal of this study was to determine whether Mycma produce siderophores and if the mycma_1113 gene expression, a putative homolog of M. tuberculosis mbtB gene located in the mbt gene cluster, is related to the synthesis of these molecules. For that, the effect of different iron concentrations on the growth of Mycma, the expression of mycma_1113 gene, and the production of siderophores was evaluated in vitro and in vivo. It is shown that Mycma produce siderophores under iron deprivation conditions and mycma_1113 gene expression was influenced by iron availability. The mycma_1113 gene expression was also increased after macrophage or in vivo infection indicating that mycobactin synthesis by Mycma could participate in the Fe sequestration from the host during infection. In conclusion, we show that Mycma produces siderophores under iron deprivation conditions and that the mycma_1113 gene is involved in this process, furthermore, this gene expression is induced during infection.

Drug delivery systems based on nanotechnology exhibit a number of advantages over traditional pharmacological formulations. Polymeric nanoparticles are commonly used as delivery systems and consist of synthetic or natural polymers that protect drugs from degradation in physiological environments. In this context, indolamine melatonin has been associated with several biological functions, including antioxidant, antitumor, immunoregulatory, neuroprotective, and cardioprotective effects. However, its availability, half-life, and absorption depend upon the route of administration, and this can limit its therapeutic potential. An alternative is the use of polymeric nanoparticle formulations associated with melatonin to increase its bioavailability and therapeutic dose at sites of interest. Thus, the objective of this review is to provide a general and concise approach to the therapeutic association between melatonin and polymeric nanoparticles applied to different biological disorders and to also highlight its advantages and potential applications compared to those of the typical drug formulations that are available.