Banca de QUALIFICAÇÃO: PAULO RICARDO PORFÍRIO DO NASCIMENTO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: PAULO RICARDO PORFÍRIO DO NASCIMENTO
DATA: 11/03/2016
HORA: 14:00
LOCAL: Sala de reuniões do Instituto de Medicina Tropical
TÍTULO:

Antigen processing and presention as a mechanism to modulate canine visceral leishmaniasis: an rna-seq approach.

PALAVRAS-CHAVES:

Dog, Transcriptome, Visceral leishmaniasis.

PÁGINAS: 28
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Background: Leishmaniasis is a complex disease that affect 300,000 people each year and another 12 million are at risk of infection throughout 90 countries in 4 continents. Dog is the main domestic reservoir of Leishmania infantum and shows a wide spectrum of clinical manifestations, varying from mild weight loss to severe hepatosplenomegaly and body spread lesions, classical signs of canine visceral leishmaniasis (CVL). The goal of this study was to evaluate the gene expression profile of spleen and peripheral blood cells from Leishmania-infected dogs and investigate microstructural alterations in spleen, liver, gut and skin in order to determine possible molecular pathways and histopathological process underlying the mechanisms related to disease progression and resistance.

Methodology: 21 animals were recruited to this study at Zoonotic Control Center in Natal-RN and a sub group was selected for transcriptomic studies. Spleen fragments were obtained from 5 mongrel dogs, one of them showing negative serology for SLA, two animals were classified as asymptomatic and other two as symptomatic. In addition, spleen, liver, gut and blood parasitism were estimated by qPCR. Total RNA was extracted and cDNA libraries were constructed and sequenced in an Illumina platform. The reads obtained were filtered and aligned against Canis familiaris genome using Bowtie. Differential gene expression was analyzed using the Cufflinks workflow, functional annotation and molecular features for each gene was obtained from Gene Ontology and KEGG database using STRINGdb. A fragment of liver, gut, skin and another spleen fragment were collected, processed and stained by HE and immunofluorescence for histopathological analysis.

 Results: We observed a marked difference in gene expression profile through FPKM value for each gene and by logFC among each comparison between spleen and peripheral blood samples from dogs with low parasite load and asymptomactic infection and against those with high parasitism and active disease. Approximately, 2,700 genes were upregulated and 2,800 downregulated in highly parasited animals. Through enrichment analysis for molecular pathways associated to visceral leishmaniasis pathogenesis, we found that NK cells activation, toll-like and NOD-like receptors pathways is highly expressed in the spleen of symptomatic ones, while GPI-anchors synthesis and immuneprotesome activation related genes is clearly downregulated in spleen of dogs with active disease and upregulated in animals with asymptomatic infection. Associated to this, we found that during active disease the classical red and white pulp spleen structure is altered, beyond an intense inflammatory infiltrate in the liver, gut and skin.

Conclusions: Taken together, these results suggests that misregulation of mechanisms classically described as acting in innate immunity is involved in CVL pathogenesis and an efficient antigen presentation maybe decisive for resistance to clinical signs development and tissue integrity during L. infantum infection in dogs.

MEMBROS DA BANCA:
Presidente - 1549705 - ADRIANA FERREIRA UCHOA
Externo ao Programa - 1164160 - IARA MARQUES DE MEDEIROS
Externo ao Programa - 1939184 - SANDRO JOSE DE SOUZA