CA9 and idiopathic pulmonary fibrosis: IHC analysis of lung tissue from mice exposed to hypoxia and receiving IPF MPCs transduced with scrambled shRNA contained more numerous human cells expressing procollagen, GPR81, and CAIX in fibrotic regions (Figure 8, M, Q, and U) compared with the lungs of mice receiving IPF MPCs in which GPR81 had been knocked down (Figure 8, O, S, and W).