Pattern-Recognition Receptor Signaling Regulator mRNA Expression in Humans and Mice, and in Transient Inflammation or Progressive Fibrosis

The cell type-, organ-, and species-specific expression of the
pattern-recognition receptors (PRRs) are well described but little
is known about the respective expression profiles of their negative
regulators. We therefore determined the mRNA expression levels of
A20, CYLD, DUBA, ST2, CD180, SIGIRR, TANK, SOCS1, SOCS3, SHIP,
IRAK-M, DOK1, DOK2, SHP1, SHP2, TOLLIP, IRF4, SIKE, NLRX1, ERBIN,
CENTB1, and Clec4a2 in human and mouse solid organs. Humans and
mice displayed significant differences between their respective
mRNA expression patterns of these factors. Additionally, we
characterized their expression profiles in mononuclear blood cells
upon bacterial endotoxin, which showed a consistent induction of
A20, SOCS3, IRAK-M, and Clec4a2 in human and murine cells.
Furthermore, we studied the expression pattern in transient kidney
ischemia-reperfusion injury versus post-ischemic atrophy and
fibrosis in mice. A20, CD180, ST2, SOCS1, SOCS3, SHIP, IRAK-M,
DOK1, DOK2, IRF4, CENTB1, and Clec4a2 were all induced, albeit at
different times of injury and repair. Progressive fibrosis was
associated with a persistent induction of these factors. Thus, the
organ- and species-specific expression patterns need to be
considered in the design and interpretation of studies related to
PRR-mediated innate immunity, which seems to be involved in tissue
injury, tissue regeneration and in progressive tissue scarring.