Lipid droplets (LD) are evolutionarily conserved lipid-enriched organelles with a diverse array of cell- and stimulus-regulated proteins. Accumulating evidence demonstrates that intracellular pathogens exploit LD as energy sources, replication sites, and part of the mechanisms of immune evasion. Nevertheless, LD can also favor the host as part of the immune and inflammatory response to pathogens. The functions of LD in the central nervous system have gained great interest due to their presence in various cell types in the brain and for their suggested involvement in neurodevelopment and neurodegenerative diseases. Only recently have the roles of LD in neuroinfections begun to be explored. Recent findings reveal that lipid remodelling and increased LD biogenesis play important roles for Zika virus (ZIKV) replication and pathogenesis in neural cells. Moreover, blocking LD formation by targeting DGAT-1 in vivo inhibited virus replication and inflammation in the brain. Therefore, targeting lipid metabolism and LD biogenesis may represent potential strategies for anti-ZIKV treatment development. Here, we review the progress in understanding LD functions in the central nervous system in the context of the host response to Zika infection.

ABSTRACT Cissampelos sympodialis Eichler, Menispermaceae, a Brazilian medicinal plant and its alkaloid warifteine present immunomodulatory activity on asthma experimental model by reducing antigen-specific IgE levels, eosinophil infiltration and lung hyperactivity. Allergic rhinitis is a chronic inflammatory disorder of the nasal tissue that affect the quality of life and it is a risk factor for asthma exacerbation. This study evaluated the effect of inhaled warifteine in an allergic ovalbumin rhinitis model. Inhaled warifteine (2 mg/ml) treatment of ovalbumin-sensitized BALB/c mice significant decreased total and differential number of cells on the nasal cavity and decreased ovalbumin-specific IgE serum levels. Hematoxylin & eosin staining of histological preparations of ovalbumin nasal tissues showed changes such as congestion and a massive cell infiltration in the perivascular and subepithelial regions characterizing the nasal inflammatory process. However, inhaled warifteine or dexamethasone treatment decreased cell infiltration into the perivascular regions and it was observed an intact nasal tissue. Periodic acidic staining of nasal epithelium of ovalbumin animals demonstrated high amount of mucus production by goblet cells and inhaled warifteine or dexamethasone treatment modulated the mucus production. In addition, toluidine blue staining of the nasal epithelium of ovalbumin animals demonstrated an increase of mast cells on the tissue and inhaled warifteine or dexamethasone treatment decreased in average of 1.4 times the number of these cells on the nasal epithelium. Taken these data together we postulate that warifteine, an immunomodulatory alkaloid, can be a medicinal molecule prototype to ameliorate the allergic rhinitis conditions.

Leprosy is an infectious disease caused by Mycobacterium leprae that affects the skin and nerves, presenting a singular clinical picture. Across the leprosy spectrum, lepromatous leprosy (LL) exhibits a classical hallmark: the presence of a collection of M. leprae-infected foamy macrophages/Schwann cells characterised by their high lipid content. The significance of this foamy aspect in mycobacterial infections has garnered renewed attention in leprosy due to the recent observation that the foamy aspect represents cells enriched in lipid droplets (LD) (also known as lipid bodies). Here, we discuss the contemporary view of LD as highly regulated organelles with key functions in M. leprae persistence in the LL end of the spectrum. The modern methods of studying this ancient disease have contributed to recent findings that describe M. leprae-triggered LD biogenesis and recruitment as effective mycobacterial intracellular strategies for acquiring lipids, sheltering and/or dampening the immune response and favouring bacterial survival, likely representing a fundamental aspect of M. leprae pathogenesis. The multifaceted functions attributed to the LD in leprosy may contribute to the development of new strategies for adjunctive anti-leprosy therapies.

Lipid bodies, inducible lipid-rich cytoplasmic inclusions, are characteristically abundant in cells associated with inflammation, including eosinophils. Here we reviewed the formation and function of lipid bodies in human eosinophils. We now have evidence that the formation of lipid bodies is not attributable to adverse mechanisms, but is centrally mediated by specific signal transduction pathways. Arachidonic acid and other cis fatty acids by an NSAID-inhibitable process, diglycerides, and PAF by a 5-lipoxygenase dependent pathway are potent stimulators of lipid body induction. Lipid body formation develops rapidly by processes that involve PKC, PLC, and de novo mRNA and protein synthesis. These structures clearly serve as repositoires of arachidonyl-phospholipids and are more than inert depots. Specific enzymes, including cytosolic phospholipase A2, MAP kinases, lipoxygenases and cyclooxygenases, associate with lipid bodies. Lipid bodies appear to be dynamic, organelle-like structures involved in intracellular pathways of lipid mobilization and metabolism. Indeed, increases in lipid body numbers correlated with enhanced production of both lipoxygenase- and cyclooxygenase-derived eicosanoids. We hypothesize that lipid bodies are distinct inducible sites for generating eicosanoids as paracrine mediators with varied activities in inflammation. The capacity of lipid body formation to be specifically and rapidly induced in leukocytes enhances eicosanoid mediator formation, and conversely pharmacologic inhibition of lipid body induction represents a potential novel and specific target for anti-inflammatory therapy.