Biology subjects

Costa, D. L.

Publications and source records attributed to Costa, D. L..

5 recordsLinked to original sources

bioRxiv2024

Reprogramming of host energy metabolism mediated by the TNF-iNOS-HIF-1alpha axis plays a key role in host resistance to Plasmodium infection

TNF has a dual effect in Plasmodium infection, bolstering the hosts immune defense while also inducing sickness behavior. Here, we confirm that TNF signaling hampers physical activity, food intake, and energy expenditure while enhancing glucose uptake by the liver and spleen as well as controlling parasitemia in P. chabaudi (Pc)-infected mice. We also report that TNF is required for expression of inducible nitric oxide synthase (iNOS), stabilization of HIF-1, expression of glucose transporter GLUT1 and enhanced glycolysis in monocytic cells from Pc-infected mice. Importantly, Pc-infected iNOS-/-, TNFR{Delta}Lyz2 and HIF-1{Delta}Lyz2 mice show impaired release of TNF and glycolysis in monocytes, along with increased parasitemia and disease tolerance. Altogether, our results indicate that TNF-iNOS-HIF-1-induced glycolysis in monocytes plays a critical role in host defense and sickness behavior in Pc-infected mice. TeaseThe role of host energy metabolism and glycolysis in monocytes as determinant of host resistance to Plasmodium infection and tolerance to disease.

immunology↗

bioRxiv2023

The heme oxygenase-1 metalloporphyrin inhibitor stannsoporfin enhances the bactericidal activity of a novel regimen for multidrug-resistant tuberculosis in a murine model

Multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb) poses significant challenges to global tuberculosis (TB) control efforts. Host-directed therapies (HDT) offer a novel approach for TB treatment by enhancing immune-mediated clearance of Mtb. Prior preclinical studies found that inhibition of heme oxygenase-1 (HO-1), an enzyme involved in heme metabolism, with tin-protoporphyrin IX (SnPP) significantly reduced mouse lung bacillary burden when co-administered with the first-line antitubercular regimen. Here we evaluated the adjunctive HDT activity of a novel HO-1 inhibitor, stannsoporfin (SnMP), in combination with a novel MDR-TB regimen comprising a next-generation diarylquinoline, TBAJ-876 (S), pretomanid (Pa), and a new oxazolidinone, TBI-223 (O) (collectively, SPaO) in Mtb-infected BALB/c mice. After 4 weeks of treatment, SPaO + SnMP 5 mg/kg reduced mean lung bacillary burden by an additional 0.69 log10 (P=0.01) relative to SPaO alone. As early as 2 weeks post-treatment initiation, SnMP adjunctive therapy differentially altered the expression of pro-inflammatory cytokine genes, and CD38, a marker of M1 macrophages. Next, we evaluated the sterilizing potential of SnMP adjunctive therapy in a mouse model of microbiological relapse. After 6 weeks of treatment, SPaO + SnMP 10 mg/kg reduced lung bacterial burdens to 0.71 {+/-} 0.23 log10 CFU, a 0.78 log-fold greater decrease in lung CFU compared to SpaO alone (P=0.005). However, adjunctive SnMP did not reduce microbiological relapse rates after 5 or 6 weeks of treatment. SnMP was well tolerated and did not significantly alter gross or histological lung pathology. SnMP is a promising HDT candidate requiring further study in combination with regimens for drug-resistant TB.

microbiology↗

bioRxiv2022

Parasite genotype is a major predictor of mortality from visceral leishmaniasis

Abstract/SummaryO_ST_ABSBackgroundC_ST_ABSVisceral leishmaniasis (VL) is a potentially fatal disease mainly caused by Leishmania infantum in South America and L. donovani in Asia and Africa. Disease outcomes have been associated with patient genotype, nutrition, age, sex, comorbidities, and co-infections. In this study, we examine the effects of parasite genetic variation on VL disease severity in Brazil. MethodsWe collected and sequenced the genomes of 109 L. infantum isolates from patients in northeast Brazil and retrieved matching patient clinical data from medical records, including mortality, sex, HIV co-infection and laboratory data (creatinine, haemoglobin, leukocyte and platelet counts). We identified genetic differences between parasite isolates, including single nucleotide polymorphisms (SNPs), small insertions/deletions (indels), and variations in genic, intergenic, and chromosome copy numbers (copy number variants, CNVs). To describe associations between the parasite genotypes and clinical outcomes, we applied quantitative genetics methods of heritability and genome-wide association studies (GWAS), treating clinical outcomes as traits that may be influenced by parasite genotype. FindingsMultiple aspects of the genetic analysis indicate that parasite genotype affects clinical outcomes. We estimate that parasite genotype explains 83% chance of mortality (narrow sense heritability, h2 = 0{middle dot}83{+/-}0{middle dot}17), and has a significant relationship with patient sex (h2 = 0{middle dot}60{+/-}0{middle dot}27). Impacts of parasite genotype on other clinical traits are lower (h2 [≤]0{middle dot}34). GWAS analysis identified multiple parasite genetic loci that were significantly associated with clinical outcomes; 17 CNVs that were significantly associated with mortality, two with creatinine and one with bacterial co-infection, jaundice and HIV co-infection; and two SNPs/indels and six CNVs that associate with age, jaundice, HIV and bacterial co-infections, creatinine, and/or bleeding sites. InterpretationParasite genotype is an important factor in VL disease severity in Brazil. Our analysis indicates that specific genetic differences between parasites act as virulence factors, enhancing risks of severe disease and mortality. More detailed understanding of these virulence factors could be exploited for novel therapies. Author SummaryMultiple factors contribute to the risk of mortality from visceral leishmaniasis (VL), including, patient genotype, comorbidities, and nutrition. Many of these factors will be influenced by socio-economic biases 1. Our work suggests that the virulence of the infecting parasite is an important risk factor for mortality. We pinpoint some specific genomic markers that are associated with mortality, which can lead to a greater understanding of the molecular mechanisms that cause severe VL disease, to genetic markers for virulent parasites and to the development of drug and vaccine therapies.

evolutionary biology↗

bioRxiv2021

Multiple targets of balancing selection in Leishmania donovani complex parasites

The Leishmania donovani species complex are the causative agents of visceral leishmaniasis, which cause 20-40,000 fatalities a year. Here, we conduct a screen for balancing selection in this species complex. We used 387 publicly-available L. donovani and L. infantum genomes, and sequence 93 isolates of L. infantum from Brazil to describe the global diversity of this species complex. We identify five genetically-distinct populations that are sufficiently represented by genomic data to search for signatures of selection. We find that signals of balancing selection are generally not shared between populations, consistent with transient adaptive events, rather than long-term balancing selection. We then apply multiple diversity metrics to identify candidate genes with robust signatures of balancing selection, identifying a curated set of 19 genes with robust signatures. These include zeta toxin, nodulin-like and flagellum attachment proteins. This study highlights the extent of genetic divergence between L. donovani complex parasites and provides genes for further study.

evolutionary biology↗

bioRxiv2017

Toxoplasma gondii microneme proteins 1 and 4 bind to Toll-like receptors 2 and 4 N-glycans triggering innate immune response

Infection of host cells by Toxoplasma gondii is an active process, which is regulated by secretion of microneme (MICs) and rhoptry proteins (ROPs and RONs) from specialized organelles in the apical pole of the parasite. MIC1, MIC4 and MIC6 assemble into an adhesin complex, secreted on the parasite surface and function to promote infection competency. MIC1 and MIC4 are known to bind terminal sialic acid residues and galactose residues, respectively and to induce IL-12 production from splenocytes. Here we show that rMIC1- and rMIC4-stimulated dendritic cells and macrophages to produce proinflammatory cytokines, and they do so by engaging TLR2 and TLR4. This process depends on sugar recognition, since point mutations in the carbohydrate-recognition domains (CRD) of rMIC1 and rMIC4 inhibit innate immune cells activation. HEK cells transfected with TLR2 glycomutants were selectively unresponsive to MICs. Following in vitro infection, parasites lacking MIC1 or MIC4, as well as expressing MIC proteins with point mutations in their CRD, failed to induce wild-type (WT) levels of IL-12 secretion by innate immune cells. However, only MIC1 was shown to impact systemic levels of IL-12 and IFN-{gamma} in vivo. Together, our data show that MIC1 and MIC4 interact physically with TLR2 and TLR4 N-glycans to trigger IL-12 responses, and MIC1 is playing a significant role in vivo by altering T. gondii infection competency and murine pathogenesis.\n\nAUTHOR SUMMARYToxoplasmosis is caused by the protozoan Toxoplasma gondii, belonging to the Apicomplexa phylum. This phylum comprises important parasites able to infect a broad diversity of animals, including humans. A particularity of T. gondii is its ability to invade virtually any nucleated cell of all warm-blooded animals through an active process, which depends on the secretion of adhesin proteins. These proteins are discharged by specialized organelles localized in the parasite apical region, and termed micronemes and rhoptries. We show in this study that two microneme proteins from T. gondii utilize their adhesion activity to stimulate innate immunity. These microneme proteins, denoted MIC1 and MIC4, recognize specific sugars on receptors expressed on the surface of mammalian immune cells. This binding activates these innate immune cells to secrete cytokines, which promotes efficient host defense mechanisms against the parasite and regulate their pathogenesis. This activity promotes a chronic infection by controlling parasite replication during acute infection.

immunology↗