The Emerging Role of Neutrophils in Repair after Acute Lung Injury

Abstract

Neutrophils are key players in acute lung injury. Once recruited from the circulation, these cells release cytotoxic molecules that lead to tissue disruption, so their blockade has been advocated to prevent lung damage. However, lung injury also occurs during neutropenia and usually involves a very poor outcome. There is emerging evidence that neutrophils not only contribute to that early damage but also orchestrate later repair. Neutrophils promote epithelial proliferation and are a source of proteases, which are required for the processing of the collagen scar and facilitation of cell migration. This article reviews the effects of neutrophils in repair after acute lung injury, focusing on their role as biovectors for proteases and other molecules involved in tissue remodeling.

More friend than foe: the emerging role of neutrophils in tissue repair

“…In this early phase, neutrophil-induced tissue damage might be inevitable in light of the important task at hand and might even be necessary to initiate proper tissue restoration. Neutrophils phagocytose cellular debris but then importantly contribute to neovascularization and promote normal collagen deposition and remodeling (69,145). The view of neutrophils as unrestrained killers seems evolutionarily flawed, and we would argue that neutrophils both partake in the proinflammatory response to tissue injury and also pave the way for its antiinflammatory and repair phases.…”

Pulmonary natural killer cells control neutrophil intravascular motility and response to acute inflammation

“…A better understanding of the interaction of leukocytes in the lung is required for us to find new pathways to influence the outcome of lung inflammation. Lung pathology in response to infection is mainly caused by neutrophil-driven tissue damage after infiltration but neutrophils are also required for the effective elimination of pathogens and the repair of lung tissue (18). Whereas NK cells are important anti-tumour cells (2), neutrophils have been implicated in every stage of cancer development including metastasis to the lung (19,20).…”

Airway-associated macrophages in homeostasis and repair

“…For example, at 1 and 3dpP we detected an increase in neutrophils, monocytes and macrophages. Neutrophils are thought to be key in modulating the cytokine environment to foster recruitment and differentiation of other immune players (Blázquez-Prieto et al, 2018;Kaplanski et al, 2003;Lechner et al, 2017;Mindt et al, 2018;Ricardo-Gonzalez et al, 2018). In the monocyte and macrophage compartment, we observed a shift toward M2-like polarization of macrophages.…”