title: Natural Schistosoma mansoni Infection in the Wild Reservoir Nectomys squamipes Leads to Excessive Lipid Droplet Accumulation in Hepatocytes in the Absence of Liver Functional Impairment.
abstract: Schistosomiasis is a neglected tropical disease of a significant public health impact. The water rat Nectomys squamipes is one of the most important non-human hosts in the schistosomiasis mansoni transmission in Brazil, being considered a wild reservoir. Cellular mechanisms that contribute to the physiological adaptation of this rodent to the Schistosoma mansoni parasite are poorly understood. Here we identified, for the first time, that a hepatic steatosis, a condition characterized by excessive lipid accumulation with formation of lipid droplets (LDs) within hepatocytes, occurs in response to the natural S. mansoni infection of N. squamipes, captured in an endemic region. Significant increases of LD area in the hepatic tissue and LD numbers/hepatocyte, detected by quantitative histopathological and ultrastructural analyses, were paralleled by increased serum profile (total cholesterol and triglycerides) in infected compared to uninfected animals. Raman spectroscopy showed high content of polyunsaturated fatty acids (PUFAs) in the liver of both groups. MALDI-TOFF mass spectroscopy revealed an amplified pool of omega-6 PUFA arachidonic acid in the liver of infected animals. Assessment of liver functional activity by the levels of hepatic transaminases (ALT and AST) did not detect any alteration during the natural infection. In summary, this work demonstrates that the natural infection of the wild reservoir N. squamipes with S. mansoni elicits hepatic steatosis in the absence of liver functional harm and that accumulation of lipids, markedly PUFAs, coexists with low occurrence of inflammatory granulomatous processes, suggesting that lipid stores may be acting as a protective mechanism for dealing with the infection.
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036-900.
authors.forename: Kátia B
authors.initials: KB
authors.lastname: Amaral
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036-900.
authors.forename: Thiago P
authors.initials: TP
authors.lastname: Silva
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036-900.
authors.forename: Kássia K
authors.initials: KK
authors.lastname: Malta
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036-900.
authors.forename: Lívia A S
authors.initials: LA
authors.lastname: Carmo
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036-900.
authors.forename: Felipe F
authors.initials: FF
authors.lastname: Dias
authors.affiliation: Laboratory of Plasmonic Nanostructures, Molecular Spectroscopy and Structure Group, Department of Chemistry, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036-900.
authors.forename: Mariana R
authors.initials: MR
authors.lastname: Almeida
authors.affiliation: Laboratory of Plasmonic Nanostructures, Molecular Spectroscopy and Structure Group, Department of Chemistry, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036-900.
authors.forename: Gustavo F S
authors.initials: GF
authors.lastname: Andrade
authors.affiliation: Department of Physics, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036-900.
authors.forename: Jefferson S
authors.initials: JS
authors.lastname: Martins
authors.affiliation: Department of Physics, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036-900.
authors.forename: Roberto R
authors.initials: RR
authors.lastname: Pinho
authors.affiliation: Laboratory of Biology and Parasitology of Wild Reservoir Mammals, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Sócrates F
authors.initials: SF
authors.lastname: Costa-Neto
authors.affiliation: Laboratory of Biology and Parasitology of Wild Reservoir Mammals, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Rosana
authors.initials: R
authors.lastname: Gentile
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036-900.
authors.forename: Rossana C N
authors.identifier: http://orcid.org/0000-0003-1736-0806
authors.initials: RC
authors.lastname: Melo
mesh_terms: D000818:Animals; D003411:Arvicolinae / Q000378:metabolism / Q000469:parasitology; D043371:Fatty Acids, Omega-6 / Q000378:metabolism; D005234:Fatty Liver / Q000378:metabolism / Q000469:parasitology; D022781:Hepatocytes / Q000378:metabolism / Q000469:parasitology; D006801:Humans; D066292:Lipid Droplets / Q000378:metabolism*; D008099:Liver / Q000378:metabolism / Q000469:parasitology; D051381:Rats; D012550:Schistosoma mansoni; D012555:Schistosomiasis mansoni / Q000378:metabolism*
chemical_list: D043371:Fatty Acids, Omega-6