Synchronous signals

Inhalation of noxious substances and bacteria or viral particles poses a critical challenge for lung tissues, as overexuberant immune reactions can cause immunopathology. In Nature, Westphalen et al. show that alveolar macrophages instigate a protective response by initiating intercellular Ca²⁺ signaling waves that are propagated by adjoining alveolar epithelial cells. Challenge with lipopolysaccharide induces transient waves of synchronous Ca²⁺ spikes that are transmitted between cells via gap junctions formed by connexin 43 (Cx43). This response triggers activation of the Ca²⁺-dependent kinase CAMKK and Akt, which prevent excessive cytokine and chemokine release. Mice lacking alveolar macrophage expression of Cx43 are more susceptible to lung injury in response to endotoxin. These findings suggest that intercellular collaboration protects delicate lung tissues.

Nature 506, 503–506 (2014)