Background: Pregnant individuals who participate in physical activity throughout gestation have been shown to experience a wide spectrum of health benefits, along with the fetus. In nonpregnant populations, PA influences the polarization state of tissue resident macrophages, resulting in increased regulatory and decreased inflammatory profiles. The effects of PA on placenta-resident macrophages, or Hofbauer cells (HBCs), remains unknown. My thesis aimed to explore this novel area. Methods: The first objective of my thesis was to identify any associations between gestational PA and HBC polarization. PA was objectively measured in both mid (24-28 weeks) and late (34-38 weeks) pregnancy using accelerometry. Immunofluorescent localization of the panmacrophage marker CD68 and the anti-inflammatory macrophage marker CD206 was used to assess polarization states. Protein and gene expression of CD68 and CD206 were assessed using Western blot and qPCR, respectively. The second objective was to explore the relationships between gestational PA, HBC polarization, and angiogenic factors in the placenta. Western blot measured the relative protein expression of FGF2 and SPRY2, and the localization of FGF2, SPRY2, and VEGF within HBCs was explored using immunofluorescent colocalization in term placenta tissue and primary HBC cultures. Results: While there were no differences in the absolute numbers of total or CD206+ HBCs, the proportion of CD206+ HBCs was elevated in active individuals. There were no significant differences in the gene expression of CD68 or CD206, nor in the gene expression of CD206; however, CD206 protein expression was observed to be lower in active participants. Both CD206+ and CD206- HBCs expressed VEGF. Active individuals had significantly higher low molecular weight-FGF2. There were no differences in the protein expression of SPRY2, total FGF2, or high molecular weight FGF2 based on PA. HBCs both in vitro and in vivo of all polarizations expressed VEGF, SPRY2, and FGF2, and were observed to create intracellular junctions and multi-nucleated giant cells. Conclusions: In conclusion, PA was associated with a higher proportion of CD206+ HBCs and reduced levels of CD206 protein. In combination with the lack of significant difference in CD206 mRNA based on PA levels, this suggests a potential effect mediated by PA on the transcriptional regulation of CD206. HBCs were seen to express SPRY2, VEGF, and FGF2, identifying them as potential players in angiogenesis regulation in the placenta. The elevated levels of low molecular weight FGF2 in active individuals suggests the PA may play a role in the modulation of placental angiogenesis. Future research should continue to explore the relationships between PA, HBC polarization, and angiogenesis.

O Zika vírus (ZIKV) pertence à família flaviviridae que inclui espécies transmitidas principalmente por mosquitos Aedes sp. No Brasil, casos de microcefalia fetal foram associados à infecção congênita por ZIKV. Vários mecanismos de imunorregulação operantes durante a gestação como a inflamação gerada e resposta antiviral são vitais para o entendimento da infecção congênita do ZIKV. Desta forma, é proposto avaliar se a inflamação via ativação do receptor Toll-like 4 (TLR4-LPS) em vilos placentários humanos e em modelo murino interfere na infecção por ZIKV. Para isso, explantes de vilos placentários humanos de 3o trimestre foram ativados com LPS e posteriormente infectados com ZIKV. Nossos achados mostram que a ativação com LPS é capaz de aumentar a replicação de ZIKV em vilos placentários e de elevar a atividade enzimática da lactato desidrogenase, indicativo de ativação celular. A replicação viral foi inibida com o tratamento dos explantes com um antioxidante, Naringenina, mostrando potencial terapêutico. A ativação placentária com LPS inibiu a via IRF-3, diminuindo a atividade antiviral e aumentando a clivagem proteica do componente da via de autofagia LC3, sendo que estes mecanismos podem estar relacionados com o aumento da replicação viral. Em paralelo, foi detectado aumento da produção de citocinas inflamatórias e hiperplasia das células de Hofbauer nos explantes inflamados e infectados, indicando que estes macrófagos fetais podem ser um nicho de replicação viral. Em modelo murino, evidenciamos que a inoculação intravaginal de LPS em fêmeas prenhas previamente à infecção com ZIKV é capaz de promover o aumento de carga viral no cérebro das mães e da prole, com agravamento do quadro de microcefalia nos fetos. Em conjunto, os dados mostram que em modelo de explante placentário humano e, in vivo , em camundongos, a inflamação é fator predisponente da replicação do ZIKV. As estratégias imunomoduladoras mostram potencial terapêutico, atenuando a resposta inflamatória e a diminuição da replicação viral. / The Zika virus (ZIKV) belongs to the flaviviridae family that includes species transmitted mainly by mosquitoes Aedes sp. In Brazil, cases of fetal microcephaly were associated with ZIKV congenital infection. Several mechanisms of immunoregulation operative during gestation as the inflammation generated and antiviral response are vital for the understanding of congenital ZIKV infection. Thus, it is proposed to evaluate whether inflammation via Toll-like receptor 4 (TLR4-LPS) activation in human and murine placental villi interferes with ZIKV infection. For this, human placental explants of 3rd trimester were activated with LPS and later infected with ZIKV. Our findings show that LPS activation is capable of increasing ZIKV replication in placental villi and elevating the enzymatic activity of lactate dehydrogenase, indicative of cellular activation. Viral replication was inhibited with the treatment of explants with an antioxidant, Naringenin, showing therapeutic potential. LPS placental activation inhibited the IRF-3 pathway, decreasing antiviral activity and increasing protein cleavage of the autophagy pathway component LC3, and these mechanisms may be related to increased viral replication. In parallel, increased production of inflammatory cytokines and Hofbauer cell hyperplasia were detected in inflamed and infected explants, indicating that these fetal macrophages may be a niche for viral replication. In the murine model, we demonstrated that the intravaginal inoculation of LPS in pregnant females prior to infection with ZIKV is able to promote the increase of viral load in the brains of mothers and offspring, with worsening of the microcephaly in fetuses. Together, the data show that in the model of human placental explant and, in vivo, in mice, inflammation is a predisposing factor of ZIKV replication. Immunomodulatory strategies show therapeutic potential, attenuating the inflammatory response and decreasing viral replication.

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La thérapie antirétrovirale (TAR) réduit drastiquement la transmission verticale du VIH. Cependant, des études récentes démontrent une association entre l'utilisation de la TAR pendant la grossesse, particulièrement à base d’inhibiteurs de protéases (IP), et les issues adverses, notamment l’accouchement prématuré. Les objectifs principaux de mon mémoire étaient de caractériser le profil immunitaire/inflammatoire au niveau placentaire et systémique chez les personnes enceintes vivant avec le VIH (PEVVIH) et les comparer en fonction du statut VIH et de la classe de TAR. Au niveau placentaire, l'immunotypage des cellules Hofbauer a révélé que les placentas des PEVVIH contenaient un niveau significativement plus élevé de leucocytes CD45+ attribuable à une augmentation du nombre de cellules Hofbauer que le groupe contrôle. Les analyses multivariables ont révélé que cette augmentation des cellules immunitaires était associée à un profil prédominant CD163+ dans tous les sous-groupes de TAR par rapport au groupe de contrôle. Au niveau systémique, la quantification de 12 médiateurs inflammatoires dans le plasma périphérique a révélé que la TAR à base d'IP est associée à une libération de cytokines pro-inflammatoires et antivirales significativement plus élevée par rapport à la TAR à base d'InSTI aux deux trimestres étudiés, en plus d’être associée à l’accouchement prématuré et une charge virale plus élevée au deuxième trimestre. Ces résultats suggèrent que la classe de TAR n'affecte pas intrinsèquement la sélection des cellules Hofbauer CD163+ et CD68+ au niveau placentaire, mais que la TAR à base d'IP est associée à une réponse immunologique distincte qui augmente le risque d'accouchement prématuré. / Antiretroviral therapy (ART) drastically reduces vertical transmission of HIV. However, recent studies demonstrate an association between the use of ART during pregnancy, particularly protease inhibitor (PI)-based ART, and adverse outcomes, including preterm delivery. The main objectives of my dissertation were to characterize the inflammatory profile at the placental and systemic levels in pregnant people living with HIV (PPLWH) and compare them according to HIV status and ART class. At the placental level, Hofbauer cell immunotyping revealed that placentas of PPLWH contained a significantly higher number of CD45+ leukocytes due to an increase in Hofbauer cells compared to controls. Multivariate analyses revealed that this increase in immune cells was associated with a predominantly CD163+ profile in all ART subgroups compared with the control group. At the systemic level, the quantification of 12 inflammatory mediators in peripheral plasma revealed that PI-based ART was associated with significantly higher pro-inflammatory and antiviral cytokine release compared to InSTI-based ART in both trimesters studied, in addition to being associated with preterm delivery and higher viral load. These results suggest that the class of ART does not intrinsically affect the selection of CD163+ and CD68+ Hofbauer cells in the placenta, but that PI-based ART is associated with a distinct immunological response which may increase the risk of preterm delivery.