SPARC and idiopathic pulmonary fibrosis: Meanwhile, single-cell RNA sequencing identified increased gene expression of SPARC in the monocytes of patients with ARDS [29], and overexpression of SPARC in IPF potentially drove tissue fibrosis via induction of PAI-1 expression, leading to a pool of myofibroblasts that are resistant to apoptosis and, consequently, a dysregulated milieu in the extracellular matrix [36].