Table 1.

The origins and target cells of AMPs in the pathogenesis of psoriasis.

AMPs	Origins	Target cells	Potential mechanism in the pathogenesis of psoriasis
Cathelicidin (LL-37)	Keratinocytes Neutrophils T cells Monocytes NK-cells Mast cells	Keratinocytes pDCs mDCs Monocytes/ macrophages Neutrophils CD4+ T cells CD8+ T cells	Forming complex with DNA/RNA to activate pDCs or mDCs through TLR dependent manner[27–30]; Priming keratinocytes for inflammation[25,34–36]; Serving as an autoantigen directly activating CD4+ and/or CD8+ T cells[17]; Driving monocyte polarization toward the CD14highCD16+ subset.[42]
Human β-defensin 2	Keratinocytes LCs	Keratinocytes pDCs Macrophages	Inducing keratinocyte proliferation and secretion[50]; Promoting the uptake of self-DNA or CpG DNA by pDCs and enhance IFN-α production[54]; Promoting type I IFN production in macrophages.[57]
Human β-defensin 3	Epithelial cells (keratinocytes)	Keratinocytes pDCs mDCs LCs Monocytes/ macrophages	Inducing keratinocyte proliferation and secretion[50]; Promoting the uptake of self-DNA or CpG DNA by pDCs and enhance IFN-α production[54]; Activating mDCs in via TLR1/2[55]; Promoting type I IFN production in macrophages[58]; Increasing CD86 expression on monocytes by stimulating the ATP-gated channel P2X7.[59]
Psoriasin (S100A7)	Keratinocytes Monocytes/ macrophages	Keratinocytes Monocytes/ macrophages Neutrophils	Inducing cytokines production of keratinocytes[67]; Chemoattractant.[87]
S100A8/A9	Keratinocytes Monocytes/ macrophages Neutrophils mDCs Endothelial cells	Keratinocytes Neutrophils CD8+ T cells	Priming keratinocytes for inflammation[85]; Promoting excessive proliferation and abnormal differentiation of keratinocytes[73,82,86]; Chemoattracting and activating neutrophils[87,88]; Promoting the development of autoreactive CD8+ T cells[89]; Filling to inhibit self-activity by forming the (S100A8/S100A9)2 tetramer and activating TLR4/MD2-mediated local inflammation.[90]
S100A15	Keratinocytes	Keratinocytes	Inducing cytokines production of keratinocytes.[67]
Lipocalin 2	Neutrophils Keratinocytes mDCs Monocytes/ macrophages Aortic smooth muscle cells Adipose tissue Hepatocytes	Neutrophils	Inducing chemotaxis and cytokine secretion in neutrophils via the 24p3R and downstream p38-MAPK and ERK-1/2 signaling pathways.[15,103]
RNase 7	Keratinocytes	Keratinocytes pDCs	Promoting the sensing of self-DNA by human pDCs and keratinocytes through TLR regulation[126,127]

AMPs: Antimicrobial peptides; pDCs: Plasmacytoid dendritic cells; mDCs: Myeloid dendritic cells; LCs: Langerhans cells.