Influence of CK2 protein kinase activity on the interaction between Trypanosoma cruzi and its vertebrate and invertebrate hosts.

Chagas disease, endemic from Latin America, is caused by Trypanosoma cruzi and is transmitted by triatomine feces. This parasite undergoes complex morphological changes through its life cycle, promoted by significant changes in signal transduction pathways. The activity of protein kinase CK2 has been described in trypanosomatids. Using a specific peptide and radioactive ATP, we identified CK2 activity on the cellular surface and the cytoplasmic content in Trypanosoma cruzi, apart from the secreted form. Dephosphorylated casein promoted an increase of 48% in the secreted CK2 activity. Total extract of peritoneal macrophages from BALB/c and inactivated human serum promoted an increase of 67% and 36%, respectively, in this activity. The protein secreted by parasites was purified by HPLC and had shown compatibility with the catalytic subunit of mammalian CK2. Incubation of the parasites with CK2 inhibitors, added to the culture medium, prevented their growth. The opposite was observed when CK2 activators were used. Results of interaction between Trypanosoma cruzi and the gut of the vector have revealed that, in the presence of CK2 inhibitors, there is a reduction in the association rate. A similar inhibition profile was seen in the Trypanosoma cruzi-macrophages interaction, confirming the importance of this enzyme in the life cycle of this protozoan.

Phenolic glycolipid-1 of Mycobacterium leprae is involved in human Schwann cell line ST8814 neurotoxic phenotype.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae infection in Schwann cells. Axonopathy is considered a hallmark of leprosy neuropathy and is associated with the irreversible motor and sensory loss seen in infected patients. Although M. leprae is recognized to provoke Schwann cell dedifferentiation, the mechanisms involved in the contribution of this phenomenon to neural damage remain unclear. In the present work, we used live M. leprae to infect the immortalized human Schwann cell line ST8814. The neurotoxicity of infected Schwann cell-conditioned medium (SCCM) was then evaluated in a human neuroblastoma cell lineage and mouse neurons. ST8814 Schwann cells exposed to M. leprae affected neuronal viability by deviating glial 14 C-labeled lactate, important fuel of neuronal central metabolism, to de novo lipid synthesis. The phenolic glycolipid-1 (PGL-1) is a specific M. leprae cell wall antigen proposed to mediate bacterial-Schwann cell interaction. Therefore, we assessed the role of the PGL-1 on Schwann cell phenotype by using transgenic M. bovis (BCG)-expressing the M. leprae PGL-1. We observed that BCG-PGL-1 was able to induce a phenotype similar to M. leprae, unlike the wild-type BCG strain. We next demonstrated that this Schwann cell neurotoxic phenotype, induced by M. leprae PGL-1, occurs through the protein kinase B (Akt) pathway. Interestingly, the pharmacological inhibition of Akt by triciribine significantly reduced free fatty acid content in the SCCM from M. leprae- and BCG-PGL-1-infected Schwann cells and, hence, preventing neuronal death. Overall, these findings provide novel evidence that both M. leprae and PGL-1, induce a toxic Schwann cell phenotype, by modifying the host lipid metabolism, resulting in profound implications for neuronal loss. We consider this metabolic rewiring a new molecular mechanism to be the basis of leprosy neuropathy.

Host cholesterol influences the activity of sterol biosynthesis inhibitors in Leishmania amazonensis.

A significant percentage of exogenous cholesterol was found in promastigotes and amastigotes of all studied species of Leishmania, suggesting a biological role for this molecule. Previous studies have shown that promastigotes of Leishmania uptake more low-density lipoprotein (LDL) particles under pharmacological pressure and are more susceptible to ergosterol inhibition in the absence of exogenous sources of cholesterol. This work shows that the host's LDL is available to intracellular amastigotes and that the absence of exogenous cholesterol enhances the potency of sterol biosynthesis inhibitors in infected macrophages. A complete understanding of cholesterol transport to the parasitophorous vacuole can guide the development of a new drug class to be used in combination with sterol biosynthesis inhibitors for the treatment of leishmaniases.

Ouabain attenuates oxidative stress and modulates lipid composition in hippocampus of rats in lipopolysaccharide-induced hypocampal neuroinflammation in rats.

Our study aimed to analyze the effect of ouabain (OUA) administration on lipopolysaccharide (LPS)-induced changes in hippocampus of rats. Oxidative parameters were analyzed in Wistar rats after intraperitoneal injection of OUA (1.8 µg/kg), LPS (200 µg/kg), or OUA plus LPS or saline. To reach our goal, activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), in addition to levels of reduced glutathione (GSH), protein carbonyl (PCO) and lipid peroxidation (LPO) were evaluated. We also analyzed the membrane lipid profile and some important lipids for the nervous system, such as phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylinositol (PI), phosphatidic acid and sphingomyelin. The group that received only LPS showed increased oxidative stress, as evidenced by an increase in LPO (about twice), PCO (about three times) levels, and CAT activity (80%). Conversely, administration of LPS decreased GSH levels (55%), and GPx activity (30%), besides a reduction in the amount of PI (60%) and PC (45%). By other side, OUA alone increased the amount of PI (45%), PE (85%), and PC (70%). All harmful effects recorded were attenuated by OUA, suggesting a protective effect against LPS-induced oxidative stress. The relevance of our results extends beyond changes in oxidative parameters induced by LPS, because nanomolar doses of OUA may be useful in neurodegenerative models. Other studies on other cardenolides and substances related issues, as well as the development of new molecules derived from OUA, could also be useful in general oxidative and/or cellular stress, a condition favoring the appearance of neuronal pathologies.

Probiotic treatment during neonatal age provides optimal protection against experimental asthma through the modulation of microbiota and T cells.

The incidence of allergic diseases, which increased to epidemic proportions in developed countries over the last few decades, has been correlated with altered gut microbiota colonization. Although probiotics may play a critical role in the restoration of gut homeostasis, their efficiency in the control of allergy is controversial. Here, we aimed to investigate the effects of probiotic treatment initiated at neonatal or adult ages on the suppression of experimental ovalbumin (OVA)-induced asthma. Neonatal or adult mice were orally treated with probiotic bacteria and subjected to OVA-induced allergy. Asthma-like symptoms, microbiota composition and frequencies of the total CD4+ T lymphocytes and CD4+Foxp3+ regulatory T (Treg) cells were evaluated in both groups. Probiotic administration to neonates, but not to adults, was necessary and sufficient for the absolute prevention of experimental allergen-induced sensitization. The neonatally acquired tolerance, transferrable to probiotic-untreated adult recipients by splenic cells from tolerant donors, was associated with modulation of gut bacterial composition, augmented levels of cecum butyrate and selective accumulation of Treg cells in the airways. Our findings reveal that a cross-talk between a healthy microbiota and qualitative features inherent to neonatal T cells, especially in the Treg cell subset, might support the beneficial effect of perinatal exposure to probiotic bacteria on the development of long-term tolerance to allergens.

Brown adipose tissue remodelling induced by corticosterone in male Wistar rats.

NEW FINDINGS: What is the central question of this study? Does glucocorticoid excess disrupt brown adipose tissue (BAT) phenotype and function? What is the main finding and its importance? Glucocorticoid excess induced an extensive remodelling of interscapular BAT, resulting in a white-like phenotype in association with metabolic disturbances. Glucocorticoids might be an important modulator of BAT physiology and BAT may have a role in pathophysiology of metabolic disturbances induced by glucocorticoid excess. ABSTRACT: In mammals, brown adipose tissue (BAT) is centrally involved in energy metabolism. To test the hypothesis that glucocorticoid excess disrupts BAT phenotype and function, male Wistar rats were treated with corticosterone in drinking water for 21 days. To confirm induction of glucocorticoid excess and metabolic disturbances, adrenal weight, corticotrophin releasing hormone mRNA levels and corticosterone serum levels were measured and a glucose tolerance test and serum triacylglycerol analyses were performed. Adipose tissue deposits were excised, weighed and evaluated by a set of biochemical, histological and molecular procedures, including thin-layer chromatography, histochemistry, immunohistochemistry, quantitative real-time polymerase chain reaction, high-resolution oxygraphy, ATP synthesis and enzymatic activity measurements. The approach was successful in induction of glucocorticoid excess and metabolic disturbances. Lower body weight and increased adiposity were observed in corticosterone-treated rats. Interscapular brown adipose tissue (iBAT) showed higher sensitivity to glucocorticoids than other fat deposits. The treatment induced lipid accumulation, unilocular rearrangement, increased collagen content and decreased innervation in iBAT. Furthermore, expression of Prdm16 (P < 0.05), Ucp1 (P <0.05) and Slc7a10 (P <0.05) mRNA decreased, while expression of Fasn (P <0.05) and Lep (P <0.05) mRNA increased in brown adipose tissue. Also, the levels of UCP1 diminished (P <0.001, 2.5-fold). Finally, lower oxygen consumption (P <0.05), ATP synthesis (P <0.05) and mitochondrial content (P <0.05) were observed in iBAT of glucocorticoid-treated rats. Glucocorticoid excess induced an extensive remodelling of interscapular brown adipose tissue, resulting in a white-like phenotype in association with metabolic disturbances.

Bioactive lipids regulate Trypanosoma cruzi development.

Trypanosoma cruzi is the etiological agent of Chagas disease. These parasites undergo dramatic morphological and physiological changes during their life cycle. The human-infective metacyclic trypomastigotes differentiate from epimastigotes inside the midgut of the Triatominae insect vector. Our group has shown that the saliva and feces of Rhodnius prolixus contains a lysophospholipid, lysophosphatidylcholine (LPC), which modulates several aspects of T. cruzi infection in macrophages. LPC hydrolysis by a specific lysophospholipase D, autotaxin (ATX), generates lysophosphatidic acid (LPA). These bioactive lysophospholipids are multisignaling molecules and are found in human plasma ingested by the insect during blood feeding. Here, we show the role of LPC and LPA in T. cruzi proliferation and differentiation. Both lysophospholipids are able to induce parasite proliferation. We observed an increase in parasite growth with different fatty acyl chains, such as C18:0, C16:0, or C18:1 LPC. The dynamics of LPC and LPA effect on parasite proliferation was evaluated in vivo through a time- and space-dependent strategy in the vector gut. LPC but not LPA was also able to affect parasite metacyclogenesis. Finally, we determined LPA and LPC distribution in the parasite itself. Such bioactive lipids are associated with reservosomes of T. cruzi. To the best of our knowledge, this is the first study to suggest the role of surrounding bioactive lipids ingested during blood feeding in the control of parasite transmission.

The role of sphingolipid metabolism disruption on lipopolysaccharide-induced lung injury in mice.

AIM: This study assessed pulmonary outcomes generated by inhibiting key enzymes of sphingolipid metabolism pathways related to ceramide synthesis in a murine model of lung injury induced by lipopolysaccharide (LPS). METHODS: C57BL/6 male adult mice received LPS intratracheally and the expressions of acid sphingomyelinase (ASM), neutral sphingomyelinase (NSM), serine palmitoyl transferase (SPT) and dihydroceramide synthase (DS) were assessed at 2, 4, 6, 12 and 24 h after LPS instillation in lung homogenate (n = 30). The pharmacological inhibition of ASM, NSM, SPT and DS were assayed in other mice groups by three different doses of desipramine, GW4869, myriocin and fumonisin, respectively (n = 90). Their most effective doses were administered intraperitoneally 1 or 2 h before LPS to different animal groups (n = 120). Mice underwent determination of pulmonary mechanics, lung histopathological aspects and apoptosis. RESULTS: The expression levels of the enzymes reached their peak at 2-4 h after LPS administration. ASM inhibition attenuated alveolar collapse and GW4869 decreased lung elastance, proinflammatory cytokines' levels and was more effective to improve alveolar collapse than desipramine. On the other hand, SPT blockage aggravated lung lesion and no effects it was observed with fumonisin. Moreover, simultaneous administration of inhibitors (desipramine + GW4869, myriocin + fumonisin and all inhibitors together) resulted in no changes. CONCLUSION: Blockage of sphingomyelinases and the de novo pathways improved and aggravated lung injury, respectively, putatively suggesting specific targets to therapeutic strategies in LPS-induced lung injury.

Lipoproteins from vertebrate host blood plasma are involved in Trypanosoma cruzi epimastigote agglutination and participate in interaction with the vector insect, Rhodnius prolixus.

Chagas disease, infecting ca. 8 million people in Central and South America, is mediated by the protozoan parasite, Trypanosoma cruzi. The parasite is transmitted by the bite of blood sucking triatomine insects, such as Rhodnius prolixus, that had previously fed on parasite-infected vertebrate blood and voided their contaminated feces and urine into the wound. The stages of the parasite life cycle in both the insect vector and human host are well-known, but determinants of infection in the insect gut are complex and enigmatic. This paper examines the possible role of the R. prolixus gut agglutinins in the parasite life cycle. The results, derived from gut extracts made from R. prolixus fed on various diets with different vertebrate blood components, and cross adsorption experiments, showed for the first time that R. prolixus has two distinct gut agglutinins originating from their vertebrate blood meal, one for T. cruzi (the parasite agglutinin, PA) and the other for the erythrocytes (the hemagglutinin, HA). Again, uniquely, the results also demonstrate that these two agglutinins are derived, respectively, from the plasma and erythrocyte components of the vertebrate blood. Subsequent experiments, examining in more detail the nature of the plasma components forming the T. cruzi PA, used fractionated extracts of the vertebrate plasma (high density lipoprotein, HDL; low density lipoprotein, LDL, and delipidated plasma) in agglutination assays. The results confirmed the identity of the PA as a high density lipoprotein (HDL) in the plasma of the vertebrate blood meal which agglutinates parasites in the R. prolixus gut. In addition, the use of single or double labeled HDL in fluorescence and confocal microscopy showed the interaction of the labeled HDL with the parasite surface and its internalization at later times. Finally, results of T. cruzi parasitization of R. prolixus, incorporating various vertebrate blood components, resulted in highly significant increases in infectivity in the presence of HDL from the 2nd day of infection, thus confirming the important role of this molecule in T. cruzi infection of R. prolixus.

A Novel Antifouling Defense Strategy from Red Seaweed: Exocytosis and Deposition of Fatty Acid Derivatives at the Cell Wall Surface.

We investigated the organelles involved in the biosynthesis of fatty acid (FA) derivatives in the cortical cells of Laurencia translucida (Rhodophyta) and the effect of these compounds as antifouling (AF) agents. A bluish autofluorescence (with emission at 500 nm) within L. translucida cortical cells was observed above the thallus surface via laser scanning confocal microscopy (LSCM). A hexanic extract (HE) from L. translucida was split into two isolated fractions called hydrocarbon (HC) and lipid (LI), which were subjected to HPLC coupled to a fluorescence detector, and the same autofluorescence pattern as observed by LSCM analyses (emission at 500 nm) was revealed in the LI fraction. These fractions were analyzed by gas chromatography-mass spectrometry (GC-MS), which revealed that docosane is the primary constituent of HC, and hexadecanoic acid and cholesterol trimethylsilyl ether are the primary components of LI. Nile red (NR) labeling (lipid fluorochrome) presented a similar cellular localization to that of the autofluorescent molecules. Transmission and scanning electron microscopy (TEM and SEM) revealed vesicle transport processes involving small electron-lucent vesicles, from vacuoles to the inner cell wall. Both fractions (HC and LI) inhibited micro-fouling [HC, lower minimum inhibitory concentration (MIC) values of 0.1 µg ml(-1); LI, lower MIC value of 10 µg ml(-1)]. The results suggested that L. translucida cortical cells can produce FA derivatives (e.g. HCs and FAs) and secrete them to the thallus surface, providing a unique and novel protective mechanism against microfouling colonization in red algae.

Antileishmanial Activity of Ezetimibe: Inhibition of Sterol Biosynthesis, In Vitro Synergy with Azoles, and Efficacy in Experimental Cutaneous Leishmaniasis.

Leishmaniasis affects mainly low-income populations in tropical regions. Radical innovation in drug discovery is time-consuming and expensive, imposing severe restrictions on the ability to launch new chemical entities for the treatment of neglected diseases. Drug repositioning is an attractive strategy for addressing a specific demand more easily. In this project, we have evaluated the antileishmanial activities of 30 drugs currently in clinical use for various morbidities. Ezetimibe, clinically used to reduce intestinal cholesterol absorption in dyslipidemic patients, killed Leishmania amazonensis promastigotes with a 50% inhibitory concentration (IC50) of 30 µM. Morphological analysis revealed that ezetimibe caused the parasites to become rounded, with multiple nuclei and flagella. Analysis by gas chromatography (GC)-mass spectrometry (MS) showed that promastigotes treated with ezetimibe had smaller amounts of C-14-demethylated sterols, and accumulated more cholesterol and lanosterol, than untreated promastigotes. We then evaluated the combination of ezetimibe with well-known antileishmanial azoles. The fractional inhibitory concentration index (FICI) indicated synergy when ezetimibe was combined with ketoconazole or miconazole. The activity of ezetimibe against intracellular amastigotes was confirmed, with an IC50 of 20 µM, and ezetimibe reduced the IC90s of ketoconazole and miconazole from 11.3 and 11.5 µM to 4.14 and 8.25 µM, respectively. Subsequently, we confirmed the activity of ezetimibe in vivo, showing that it decreased lesion development and parasite loads in murine cutaneous leishmaniasis. We concluded that ezetimibe has promising antileishmanial activity and should be considered in combination with azoles in further preclinical and clinical studies.

The effect of gamma radiation on the lipid profile of irradiated red blood cells.

An investigation into the effects of irradiation and of the storage time on aging and quality are a relevant issue to ensure the safety and the efficiency of irradiation in the prevention of transfusion-associated graft-versus-host disease (TA-GVHD). In this work, the biochemical properties and alterations presented by erythrocyte membranes, up to 28-days post-irradiation, with a dose of 25 Gy, were studied as a function of storage and post-irradiation time. There was a considerable variation in the total of phospholipid content, when comparing the control and irradiated samples, mostly from the third day onwards; and at the same time, the effect occurred as a function on the storage time of blood bags. The levels of total cholesterol decreased 3-9 days after irradiation. TBARS levels were increased after irradiation and 7 days of storage, but no increment of catalase activity was observed after the irradiation. Furthermore, the protein profile was maintained throughout the irradiation and storage time, until the 21st day, with the presence of a protein fragmentation band of around 28 kDa on the 28th day. In conclusion, although gamma irradiation is the main agent for the prevention of TA-GVHD, a better understanding of the physical and biochemical properties of erythrocytes are necessary to better assess their viability, and to be able to issue more secure recommendations on the shelf life of blood bags, and the safe use of the irradiated red cells therein.

Trypanosoma cruzi infection modulates secreted phospholipase A2 expression in the salivary glands of Rhodnius prolixus.

Phospholipases A2 (PLA2) comprise a superfamily of enzymes that specifically catalyze hydrolysis of the ester bond at the sn-2 position of glycerophospholipids, generating lysophospholipids and fatty acids. In Rhodnius prolixus, one of the main vectors of the Chagas's disease etiologic agent Trypanosoma cruzi, it was previously shown that lysophosphatidylcholine, a bioactive lipid, found in the insect's saliva, contributes to the inhibition of platelet aggregation, and increases the production of nitric oxide, an important vasodilator. Due to its role in potentially generating LPC, here we studied the PLA2 present in the salivary glands of R. prolixus. PLA2 activity is approximately 100 times greater in the epithelium than in the contents of salivary glands. Our study reveals the role of the RpPLA2XIIA gene in the insect feeding performance and in the fatty acids composition of phospholipids extracted from the salivary glands. Knockdown of RpPLA2XIIA significantly altered the relative amounts of palmitic, palmitoleic, oleic and linoleic acids. A short-term decrease in the expression of RpPLA2III and RpPLA2XIIA in the salivary glands of R. prolixus was evident on the third day after infection by T. cruzi. Taken together, our results contribute to the understanding of the role of PLA2 in the salivary glands of hematophagous insects and show that the parasite is capable of modulating even tissues that are not colonized by it.

Unlocking the Secrets of Adipose Tissue: How an Obesity-Associated Secretome Promotes Osteoblast Dedifferentiation via TGF-ß1 Signaling, Paving the Path to an Adipogenic Phenotype.

BACKGROUND: Obesity poses a significant global health challenge, given its association with the excessive accumulation of adipose tissue (AT) and various systemic disruptions. Within the adipose microenvironment, expansion and enrichment with immune cells trigger the release of inflammatory mediators and growth factors, which can disrupt tissues, including bones. While obesity's contribution to bone loss is well established, the direct impact of obese AT on osteoblast maturation remains uncertain. This study aimed to explore the influence of the secretomes from obese and lean AT on osteoblast differentiation and activity. METHODS: SAOS-2 cells were exposed to the secretomes obtained by culturing human subcutaneous AT from individuals with obesity (OATS) or lean patients, and their effects on osteoblasts were evaluated. RESULTS: In the presence of the OATS, mature osteoblasts underwent dedifferentiation, showing an increased proliferation accompanied by a morphological shift towards a mesenchymal phenotype, with detrimental effects on osteogenic markers and the calcification capacity. Concurrently, the OATS promoted the expression of mesenchymal and adipogenic markers, inducing the formation of cytoplasmic lipid droplets in SAOS-2 cells exposed to an adipogenic differentiation medium. Additionally, TGF-ß1 emerged as a key mediator of these effects, as the OATS was enriched with this growth factor. CONCLUSIONS: Our findings demonstrate that obese subcutaneous AT promotes the dedifferentiation of osteoblasts and increases the adipogenic profile in these cells.

Long-term exposure to polychlorinated biphenyl 126 induces liver fibrosis and upregulates miR-155 and miR-34a in C57BL/6 mice.

Environmental pollutants, including polychlorinated biphenyls (PCBs), act as endocrine disruptors and impair various physiological processes. PCB 126 is associated with steatohepatitis, fibrosis, cirrhosis, and other hepatic injuries. These disorders can be regulated by microRNAs (miRNAs). Therefore, this study aimed to investigate the role of miRNAs in non-alcoholic fatty liver disease associated with exposure to PCB 126. Adult male C57BL/6 mice were exposed to PCB 126 (5 µmol/kg of body weight) for 10 weeks. The PCB group showed lipid accumulation in the liver in the presence of macro- and microvesicular steatosis and fibrosis with increased inflammatory and profibrotic gene expression, consistent with non-alcoholic steatohepatitis (NASH). PCB exposure also upregulated miR-155 and miR-34a, which induce the expression of proinflammatory cytokines and inflammation in the liver and reduce the expression of peroxisome proliferator-activated receptor α, which, in turn, impairs lipid oxidation and hepatic steatosis. Therefore, the present study showed that PCB 126 induced NASH via potential mechanisms involving miR-155 and miR-34a, which may contribute to the development of new diagnostic markers and therapeutic strategies.

Metabolic consequences of interesterified palm oil and PCB-126 co-exposure in C57BL/6 mice.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is defined as morphofunctional changes in the liver. Studies have shown that Westernized eating patterns and environmental pollutants can directly induce the development of MASLD. This study evaluates the effect of co-exposure to interesterified palm oil (IPO) and 3,3',4,4',5-pentachlorobiphenyl (PCB-126) on the progression of MASLD in an animal model. C57BL/6 mice were fed IPO and co-exposed to PCB-126 for ten weeks. The co-exposure led to an imbalance in carbohydrate metabolism, increased systemic inflammation markers, and morphofunctional changes in the liver. These liver changes included the presence of inflammatory cells, fibrosis, alterations in aspartate transaminase (AST) and alanine transaminase (ALT) enzymes, and imbalance in gene expression related to fatty acid ß-oxidation, de novo lipogenesis, mitochondrial dynamics, and endoplasmic reticulum stress. Separate exposures to IPO and PCB-126 affected metabolism and MASLD progression. Nutritional and lifestyle factors may potentiate the onset and severity of MASLD.

Mycobacterium leprae is able to infect adipocytes, inducing lipolysis and modulating the immune response.

Leprosy is a chronic infectious disease caused by the intracellular bacillus Mycobacterium leprae (M. leprae), which is known to infect skin macrophages and Schwann cells. Although adipose tissue is a recognized site of Mycobacterium tuberculosis infection, its role in the histopathology of leprosy was, until now, unknown. We analyzed the M. leprae capacity to infect and persist inside adipocytes, characterizing the induction of a lipolytic phenotype in adipocytes, as well as the effect of these infected cells on macrophage recruitment. We evaluated 3T3-L1-derived adipocytes, inguinal adipose tissue of SWR/J mice, and subcutaneous adipose tissue biopsies of leprosy patients. M. leprae was able to infect 3T3-L1-derived adipocytes in vitro, presenting a strong lipolytic profile after infection, followed by significant cholesterol efflux. This lipolytic phenotype was replicated in vivo by M. leprae injection into mice inguinal adipose tissue. Furthermore, M. leprae was detected inside crown-like structures in the subcutaneous adipose tissue of multibacillary patients. These data indicate that subcutaneous adipose tissue could be an important site of infection, and probably persistence, for M. leprae, being involved in the modulation of the innate immune control in leprosy via the release of cholesterol, MCP-1, and adiponectin.

Perimicrovillar membrane assembly: the fate of phospholipids synthesised by the midgut of Rhodnius prolixus.

In this study, we describe the fate of fatty acids that are incorporated from the lumen by the posterior midgut epithelium of Rhodnius prolixus and the biosynthesis of lipids. We also demonstrate that neutral lipids (NL) are transferred to the haemolymphatic lipophorin (Lp) and that phospholipids remain in the tissue in which they are organised into perimicrovillar membranes (PMMs). 3H-palmitic acid added at the luminal side of isolated midguts of R. prolixus females was readily absorbed and was used to synthesise phospholipids (80%) and NL (20%). The highest incorporation of 3H-palmitic acid was on the first day after a blood meal. The amounts of diacylglycerol (DG) and triacylglycerol synthesised by the tissue decreased in the presence of Lp in the incubation medium. The metabolic fates of 3H-lipids synthesised by the posterior midgut were followed and it was observed that DG was the major lipid released to Lp particles. However, the majority of phospholipids were not transferred to Lp, but remained in the tissue. The phospholipids that were synthesised and accumulated in the posterior midgut were found to be associated with Rhodnius luminal contents as structural components of PMMs.

Chemical Defense against Herbivory in the Brown Marine Macroalga Padina gymnospora Could Be Attributed to a New Hydrocarbon Compound.

Brown marine macroalga Padina gymnospora (Phaeophyceae, Ochrophyta) produces both secondary metabolites (phlorotannins) and precipitate calcium carbonate (CaCO3-aragonite) on its surface as potential defensive strategies against herbivory. Here, we have evaluated the effect of natural concentrations of organic extracts (dichloromethane-DI; ethyl acetate-EA and methanol-ME, and three isolated fractions) and mineralized tissues of P. gymnospora as chemical and physical resistance, respectively, against the sea urchin Lytechinus variegatus through experimental laboratory feeding bioassays. Fatty acids (FA), glycolipids (GLY), phlorotannins (PH) and hydrocarbons (HC) were also characterized and/or quantified in extracts and fractions from P. gymnospora using nuclear magnetic resonance (NMR) and gas chromatography (GC) coupled to mass spectrometry (CG/MS) or GC coupled to flame ionization detector (FID) and chemical analysis. Our results showed that chemicals from the EA extract of P. gymnospora were significantly important in reducing consumption by L. variegatus, but the CaCO3 did not act as a physical protection against consumption by this sea urchin. An enriched fraction containing 76% of the new hydrocarbon 5Z,8Z,11Z,14Z-heneicosatetraene exhibited a significant defensive property, while other chemicals found in minor amounts, such as GLY, PH, saturated and monounsaturated FAs and CaCO3 did not interfere with the susceptibility of P. gymnospora to L. variegatus consumption. We suggest that the unsaturation of the 5Z,8Z,11Z,14Z-heneicosatetraene from P. gymnospora is probably an important structural characteristic responsible for the defensive property verified against the sea urchin.