Biology subjects

Curi, R.

Publications and source records attributed to Curi, R..

3 recordsLinked to original sources

bioRxiv2023

Early inflammatory response mediated by Angiotensin II in cardiac arteries of normotensive mice.

To verify if a low dose of angiotensin II (Ang II) can induce an inflammatory response in cardiac arteries, even though blood pressure remains at normal values. Were used C57Bl/6J male mice treated with a low dose of Ang II (30ng/kg IP) and AT1R blockers. Blood pressure was recorded after 10, 30, 60min, 2 and 6hours after Saline or Ang II injection. Time curve (30 and 60min, 2, 6, 12, 24, and 48hours after treatment) for expression of inflammatory markers was evaluated in cardiac arteries (TGF-{beta}, IL-1{beta}, IL-6, TNF- and ICAM-1) by immunohistochemistry and western blot. Serum TNF- and IL-6 were analyzed by ELISA. Although Ang II did not alter blood pressure, local TGF- and IL-6 presented an early increase in cardiac arteries. IL-1{beta} and ICAM-1 participated in a late response to Ang II (12 hours). Ang II group showed a systemic increase of IL-6 30 to 60 minutes after treatment. AT1 and AT2 receptor blockers (losartan, 20mg/kg, and PD123.319, 15mg/kg) were given alone or concomitant to Ang II. This combination showed that Ang II increases TGF-{beta} and IL-6 by acting on the AT1 receptor in a fast response. IL-1{beta} regulation by Ang II seems to be mediated by both AT1 and AT2 receptors. The results suggest that, independently of hemodynamic influences, Ang II, acting on AT1R, leads to the expression of inflammatory markers in cardiac vessels. AT2 receptor seems to be involved in the counterbalance of AT1R during modulation of IL-1{beta} production in cardiac arteries.

physiology↗

bioRxiv2021

Fatty acid oxidation participates of the survival to starvation, cell cycle progression and differentiation in the insect stages of Trypanosoma cruzi

During its complex life cycle, Trypanosoma cruzi colonizes different niches in its insect and mammalian hosts. This characteristic determined the types of parasites that adapted to face challenging environmental cues. The primary environmental challenge, particularly in the insect stages, is poor nutrient availability. These T. cruzi stages could be exposed to fatty acids originating from the degradation of the perimicrovillar membrane. In this study, we revisit the metabolic fate of fatty acid breakdown in T. cruzi. Herein, we show that during parasite proliferation, the glucose concentration in the medium can regulate the fatty acid metabolism. At the stationary phase, the parasites fully oxidize fatty acids. [U-14C]-palmitate can be taken up from the medium, leading to CO2 production via beta-oxidation. Lastly, we also show that fatty acids are degraded through beta-oxidation. Additionally, through beta-oxidation, electrons are fed directly to oxidative phosphorylation, and acetyl-CoA is supplied to the tricarboxylic acid cycle, which can be used to feed other anabolic pathways such as the de novo biosynthesis of fatty acids. Author SummaryTrypanosoma cruzi is a protist parasite with a life cycle involving two types of hosts, a vertebrate one (which includes humans, causing Chagas disease) and an invertebrate one (kissing bugs, which vectorize the infection among mammals). In both hosts, the parasite faces environmental challenges such as sudden changes in the metabolic composition of the medium in which they develop, severe starvation, osmotic stress and redox imbalance, among others. Because kissing bugs feed infrequently in nature, an intriguing aspect of T. cruzi biology (it exclusively inhabits the digestive tube of these insects) is how they subsist during long periods of starvation. In this work, we show that this parasite performs a metabolic switch from glucose consumption to lipid oxidation, and it is able to consume lipids and the lipid-derived fatty acids from both internal origins as well as externally supplied compounds. When fatty acid oxidation is chemically inhibited by etomoxir, a very well-known drug that inhibits the translocation of fatty acids into the mitochondria, the proliferative insect stage of the parasites has dramatically diminished survival under severe metabolic stress and its differentiation into its infective forms is impaired. Our findings place fatty acids in the centre of the scene regarding their extraordinary resistance to nutrient-depleted environments.

biochemistry↗

bioRxiv2020

Sensing soluble uric acid by Naip1-Nlrp3 platform

The immune system can recognize microbes and sterile tissue damage. Among the damage-associated molecular patterns (DAMPs), uric acid is considered a major component which can trigger inflammation. It represents a breakpoint in the evolutionary history of humans as our ancestors lost the uricase gene, the enzyme responsible for its cleavage. High soluble uric acid (sUA) concentration is able to increase IL-1{beta} in murine, but not human macrophages. We observed that sUA increased the mRNA expression of Naip1 in murine macrophages, and, therefore, we hypothesized that the recognition of sUA can be made by a Naip1-Nlrp3 inflammasome platform. Additionally, we used genome-wide transcriptome analysis, functional analyses and structural modeling predictions and observed that virus-transduction of murine Naip1 into human macrophages induced IL-1{beta} after sUA stimulus, besides leading to fatty acid production and an inflammation-related response. Moreover, pharmacologic inhibition and genetic loss of Nlrp3 led to decreased IL-1{beta} production upon sUA stimulus. Surface plasmon resonance and quartz crystal microbalance showed that sUA is able to interact with Naip1. Naip could be a lost receptor for sUA in the evolutionary process and a better understanding of the immune modulatory function of sUA could lead to design rational novel anti-hyperuricemic therapies.

immunology↗