The ingestion of apoptotic corpses by macrophages, a process called efferocytosis, is a crucial step in inflammation resolution, since it alters macrophage phenotype toward a pro-resolving profile to foil inflammation and to favor tissue repair. Up to now, the resolving macrophages remain poorly characterized, especially in humans. Global investigations, like RNA sequencing, would be very helpful to unravel some features of these elusive cells. Nonetheless, these inquiries may be challenging in a single-species model, since the fate of ingested mRNA remains unknown and may hinder any subsequent mRNA investigations in the phagocyte. A full human model consisting of primary human neutrophil and primary human monocyte-derived macrophage co-culture was set up several decades ago to mimic in vitro the efferocytosis process. However, to our knowledge, this model has not been characterized as a suitable model to perform global mRNA investigations. Indeed, the extent of ingested neutrophil mRNA contamination has not been assessed in resolving macrophages. This work answers to this crucial question. Indeed, based on the protocols presented in this article, we demonstrate that neutrophil mRNA is severely degraded and is not able to cross-contaminate resolving macrophage mRNA, contrary to apoptotic human peripheral blood derived mononuclear cell (PBMC) or apoptotic leukemic Jurkat cell mRNA. Moreover, this allogenic co-culture system does not favor neither neutrophil activation nor macrophage pro-inflammatory cytokine release. Collectively, we highlight that this model of primary human neutrophil and primary human monocyte-derived macrophage co-culture is the best model for mRNA investigations in human resolving macrophages to help improving our knowledge on these crucial cells.

巨噬细胞摄取凋亡的尸体（称为胞吞作用）是炎症消退的关键步骤，因为它会改变巨噬细胞的表型，使其趋向于亲分解特征，从而阻止炎症并促进组织修复。到目前为止，可分辨的巨噬细胞仍然缺乏特征，特别是在人类中。像RNA测序这样的全球性研究对于揭示这些难以捉摸的细胞的某些特征将非常有帮助。但是，这些查询在单物种模型中可能具有挑战性，因为所摄入的mRNA的命运仍然未知，并且可能阻碍吞噬细胞中随后的任何mRNA研究。由初级人中性粒细胞和初级人单核细胞源性巨噬细胞共培养的完整人体模型成立了几十年前以模仿体外胞吐过程。然而，据我们所知，该模型尚未被表征为进行全局mRNA研究的合适模型。实际上，在解析巨噬细胞时尚未评估摄入的中性粒细胞mRNA污染程度。这项工作回答了这个关键问题。确实，根据本文介绍的方案，我们证明嗜中性粒细胞mRNA严重降解且不能交叉污染解析巨噬细胞mRNA，这与凋亡的人外周血单核细胞（PBMC）或凋亡的白血病Jurkat细胞mRNA相反。而且，这种同种异体共培养系统既不促进嗜中性粒细胞活化也不促进巨噬细胞促炎细胞因子的释放。总的来说，