Acidosis is among the least studied secondary injury mechanisms associated with neurotrauma. Acute decreases in brain pH correlate with poor long‐term outcome in patients with traumatic brain injury (TBI), however, the temporal dynamics and underlying mechanisms are unclear. As key drivers of neuroinflammation, we hypothesized that microglia directly regulate acidosis after TBI, and thereby, worsen neurological outcomes. Using a controlled cortical impact model in adult male mice we demonstrate that intracellular pH in microglia and extracellular pH surrounding the lesion site are significantly reduced for weeks after injury. Microglia proliferation and production of reactive oxygen species (ROS) were also increased during the first week, mirroring the increase in extracellular ROS levels seen around the lesion site. Microglia depletion by a colony stimulating factor 1 receptor (CSF1R) inhibitor, PLX5622, markedly decreased extracellular acidosis, ROS production, and inflammation in the brain after injury. Mechanistically, we identified that the voltage‐gated proton channel Hv1 promotes oxidative burst activity and acid extrusion in microglia. Compared to wildtype controls, microglia lacking Hv1 showed reduced ability to generate ROS and extrude protons. Importantly, Hv1‐deficient mice exhibited reduced pathological acidosis and inflammation after TBI, leading to long‐term neuroprotection and functional recovery. Our data therefore establish the microglial Hv1 proton channel as an important link that integrates inflammation and acidosis within the injury microenvironment during head injury.

Sex prevalence in lung disease suggests that sex-specific hormones may contribute to the pathogenesis and/or progression of at least some lung diseases, such as lung adenocarcinoma, lymphangioleiomyomatosis (LAM) and benign metastasising leiomyoma (BML). Oestrogen is an important hormone in normal lung development and in the pathogenesis of female predominant pulmonary diseases. In vivo and in vitro studies have facilitated our understanding of disease pathogenesis and discovery of potential therapeutic targets. Oestrogen promoted disease progression in cell and animal models of lung adenocarcinoma, LAM and BML. Specifically, oestrogen enhanced tumour growth and metastasis in animal models of these diseases. Furthermore, 17β-estradiol (E2), the most abundant form of oestrogen in humans, increased the size and proliferation of cultured cells of lung adenocarcinoma and LAM. Coupled with the known mechanisms of oestrogen metabolism and signalling, these model systems may provide insights into the diverse effects of oestrogen and other hormones on lung diseases. Anti-oestrogen treatments that target key events of oestrogen synthesis or signalling, such as aromatase activity, oestrogen receptors and signalling pathways, may offer additional opportunities for clinical trials.

The perivascular astrocyte endfoot is a specialized and diffusion-limited subcellular compartment that fully ensheathes the cerebral vasculature. Despite their ubiquitous presence, a detailed understanding of endfoot physiology remains elusive, in part due to a limited understanding of the proteins that distinguish the endfoot from the greater astrocyte body. Here, we developed a technique to isolate astrocyte endfeet from brain tissue, which was used to study the endfoot proteome in comparison to the astrocyte somata. In our approach, brain microvessels, which retain their endfoot processes, were isolated from mouse brain and dissociated, whereupon endfeet were recovered using an antibody-based column astrocyte isolation kit. Our findings expand the known set of proteins enriched at the endfoot from 10 to 516, which comprised more than 1/5th of the entire detected astrocyte proteome. Numerous critical electron transport chain proteins were expressed only at the endfeet, while enzymes involved in glycogen storage were distributed to the somata, indicating subcellular metabolic compartmentalization. The endfoot proteome also included numerous proteins that, while known to have important contributions to blood-brain barrier function, were not previously known to localize to the endfoot. Our findings highlight the importance of the endfoot and suggest new routes of investigation into endfoot function.