Banca de DEFESA: CLARISSA LEAL SILVA E SOUZA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : CLARISSA LEAL SILVA E SOUZA
DATA : 02/12/2019
HORA: 08:00
LOCAL: Instituto Multidisciplinar em Saúde
TÍTULO:

Evaluation of the role of the monocyte / macrophage immune response induced by Staphylococcus aureus.

PALAVRAS-CHAVES:

Sexual dimorphism. 17β-estradiol. Monocytes. Macrophages. Ovariectomy. Staphylococcus aureus.

PÁGINAS: 128
GRANDE ÁREA: Ciências Biológicas
ÁREA: Fisiologia
SUBÁREA: Fisiologia de Órgãos e Sistemas
ESPECIALIDADE: Fisiologia Endócrina
RESUMO:

Clinical and experimental evidence supports the hypothesis that sex steroids regulate the immune response and thus exert effects on adverse pathological conditions such as bacterial infections. In general, the hormonal influence paradigm on the immune response stipulates that estrogen increases this response, while testosterone suppresses it. However, data in the literature are still controversial. Still, there is a gap regarding the role of estrogen in infections with Gram-positive bacteria such as S. aureus. The aim of this study was to evaluate the influence of ovariectomy and 17β-estradiol on S. aureus-induced immune response in an in vitro model of murine peritoneal macrophages (MPMs) and human peripheral blood monocytes (hPMs) and in an in vivo model. For this, female BALB / c mice were ovariectomized (OVX) or sham operated (Sham). In the animal model, females were inoculated intraperitoneally with S. aureus ATCC 25923 or sterile saline. The animals were euthanized at 7 different periods with 24-hour interval each and 10 females (n = 5 Sham / n = 5 OVX) were grouped for each period. After euthanasia, blood samples were collected for total and differential leukocyte count and quantification of S. aureus by RT-PCR. The uterus and spleen were removed and weighed. The serum was intended for evaluation of estradiol levels. The lungs were removed and fractionated for immunohistochemical analysis for macrophage detection (anti-CD68) and relative gene expression of IL-6, IL-1β and TNF-α by RT-PCR. The results showed that OVX females had splenomegaly and late monocyte response compared to shams. Intraperitoneal inoculation caused bacteremia in both groups, and OVX females presented late pulmonary recruitment of macrophages. In addition, OVX females showed higher gene expression of IL-1β, TNF-α and IL-6. Higher IL-6 expression compared to sham females was observed even in the absence of infection. In the in vitro model, thioglycolate-induced peritoneal macrophages (2 x 105 ) of female shams (n = 3), OVX (n = 3) and male (n = 3) mice were inoculated with S. aureus for 6 hours. Macrophages obtained from OVX females and males were previously treated for 24 hours with 17βestradiol (E2) (10-7 M). The macrophages were collected and destined to evaluate the relative gene expression of TNF-α, IL-1β, IL-6, IL-8 and TLR2. Results showed that E2 treatment decreased cytokines gene expression, except for IL-8, in which male MPMs showed increased expression. Also, E2 decreases TLR2 receptor gene expression. In the in vitro model of hPMs, six men and six women were selected and hPMs were isolated from peripheral blood samples of the volunteers. In women, blood was collected in both menstrual and fertile periods. After 24h in a CO2 oven, the hPMs were inoculated by S. aureus for 6 hours. After this period, the supernatant was collected for Luminex cytokine analysis and the hPMs removed for analysis of 84 genes involved in host response to bacterial infections by RT-PCR array. Compared to male hPMs, it was observed that E2-treated male hPMs produced less TNF-α, IL-1 and IL-6 and more IL-23, IL-27 and GM-CSF, and women's hPMs in the fertile period produced less TNF-α, IL-1 and produced more IL-10, IL-12, IL-23 and IL-27. Compared to hPMs from women in menstrual period, the hPMs from women in the fertile period produced more IL-12. Male hPMs treated with E2 and hPMs of women in the fertile period expressed less TRL2 than male hPMs. According to the analysis of gene expression it was possible to infer that E2 inhibited the NFκB pathway. It is concluded that estrogen acts as an immunoprotectant by modulating an antiinflammatory action on the immune response induced by S. aureus. Keywords: Sexual dimorphism. 17β-estradiol.

MEMBROS DA BANCA:
Interno - 1552395 - TELMA DE JESUS SOARES
Interno - 1561874 - LUCAS MIRANDA MARQUES
Interno - 1112111 - AMELIA CRISTINA MENDES DE MAGALHAES GUSMAO
Externo ao Programa - 2418292 - SAMIRA ITANA DE SOUZA
Externo ao Programa - 2342538 - GUILHERME BARRETO CAMPOS