In our studies, Tuj1+ pericytes are also localized in close proximity to Arg1+ pro-fibrotic macrophages within fibrotic regions, and the absence of Tuj1 in pericytes exacerbates pulmonary fibrosis following fibrotic stimuli, suggesting that Tuj1+ pericytes negatively regulate these macrophages through CXCL10. The gene discussed is ARG1; the disease is pulmonary fibrosis.