Soraya Mezouar

By Soraya Mezouar and Jean-Louis Mege

The placenta is a unique temporary organ essential for growth of the fetus, which determines the success of pregnancy. Its originality relies on a combination of nutritive, endocrine and immunological functions that control maternal immune tolerance to fetus. In the present chapter, we review gene expression programs of placenta from placenta tissue to isolated cells using high throughput transcriptomic approach. Beside trophoblasts, we focused on immune cells including macrophages, dendritic cells and mast cells. From the gene expression signatures, we identify key pathways for the different trimesters of the normal pregnancy and pathological alterations including preeclampsia and gestational diabetes mellitus.

Part of the book: Placenta

By Soraya Mezouar and Jean-Louis Mege

Macrophages are tissue immune cells involved in homeostasis and are considered as the first line of defense during bacterial infections. They are resident cells but may be recruited during inflammation and/or infection. Hence, their study is necessary not only to decipher innate immune mechanisms involved in bacterial infections but also to follow infected patients. Among the numerous functions of macrophages, their polarization into microbicidal or permissive cells has been an interesting concept to describe their responses to bacterial aggression. Numerous in vitro studies, including ours, have shown the ability of bacteria to induce different patterns of macrophage polarization. However, the studies of patients during infections have produced less convincing results. We propose in this review to take stock of the tools for studying the polarization of macrophages and to show their limits. We make recommendations for using macrophage polarization as a biomarker for measuring severity and response to treatment in bacterial infectious diseases.

Part of the book: Macrophages

By Perla Abou Atmeh, Soraya Mezouar and Jean-Louis Mège

The role of macrophages in viral infections is well documented. Their activation status also called macrophage polarization categorized by the dichotomy of M1 and M2 phenotype remained poorly investigated. Recent studies have shown the complexity of macrophage polarization in response to viral infection and the limits of its use in infected individuals. The aim of this chapter is to reappraise the concept of macrophage polarization in viral infectious diseases, which are more complicated than the models of macrophage-virus interaction. If this concept has been largely used to describe activation status of myeloid cells in experimental conditions, it has to be assessed in light of high-throughput technologies at molecular and phenotypic levels. We update knowledge on macrophage polarization in viral infectious diseases with a special attention for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection leading to coronavirus disease (COVID-19). Hence, we propose an overview of the concept of macrophages as targets for therapeutic intervention in viral infectious disease. Finally, we tempted to focus our approach on patient investigation restricting the use of in vitro experiments and animal models to mechanistic questions.

Part of the book: Macrophages