Type 3 Inflammation-Specific Keratinocyte Glutaminolysis Promotes Skin Inflammation.

Inflammatory cytokines reprogram keratinocyte metabolism, but the metabolic pathways that couple immune signals to pathological epidermal growth remain incompletely defined. Here, we identify GLS1-mediated glutaminolysis as a metabolic program preferentially induced in keratinocytes under type 3 inflammatory conditions. Integrated transcriptomic, metabolomic, genetic, and functional analyses showed that IL-17A induced GLS1 expression and glutaminolysis in keratinocytes. Keratinocyte-specific Gls1 deletion reduced the intracellular availability of arginine, proline, and methionine, impaired amino acid-dependent mTORC1 activation, disrupted redox homeostasis, and limited keratinocyte proliferation. Amino acid or antioxidant supplementation partially rescued these defects, whereas rapamycin blocked the amino acid-mediated proliferative rescue. Gls1 deletion did not impair steady-state skin development or homeostasis and did not alter MC903-induced type 2 dermatitis, but it delayed wound re-epithelialization and attenuated IMQ-induced psoriasiform inflammation. Loss of keratinocyte GLS1 also reduced epidermal chemokine expression and the accumulation of neutrophils and IL-17A-producing γδ T cells, revealing a role for glutaminolysis in amplifying epithelial-immune crosstalk. These findings define GLS1-mediated glutaminolysis as a context-specific metabolic checkpoint linking type 3 inflammation to keratinocyte proliferation and cutaneous immune amplification, and support locally or temporally controlled GLS1 inhibition as a potential therapeutic strategy for psoriasis.