A timed, keratinocyte-only deletion of the m6A writer Mettl3 produced sterile pustules on the palms and soles of mice that mirror human palmoplantar pustulosis, researchers report in late-breaking abstract LB789, slated for the Journal of Investigative Dermatology's October 2026 supplement (Volume 146, Issue 10).

A team led by Lian Cui, Yuye Wang, and Yuling Shi uses an inducible system: the gene disappears from keratinocytes only after tamoxifen is given, so the mice develop normally before the epidermis loses Mettl3. That timing separates developmental confounders from adult skin biology.

Why Mettl3? It writes N6-methyladenosine, the most common internal mRNA modification in mammals. Earlier mouse work linked epidermal Mettl3 to keratinocyte proliferation, differentiation, and inflammatory signaling, but no group had tied its loss to a PPP-like phenotype until now.

The abstract's second half is mechanistic. The team implicates the PPARα-STAT3 axis as the conduit through which Mettl3 loss drives pustule formation. They stop short of clinical claims, which is appropriate for a late-breaking preclinical readout.

Why does PPP need its own model?

Palmoplantar pustulosis has trailed the rest of inflammatory skin disease on the modeling side. Imiquimod, IL-23 injection, and several transgenic lines each capture pieces of plaque psoriasis but reproduce palmar-plantar pustules inconsistently. A clean inducible PPP model closes that gap. It also gives the field a system in which drug response can be read out on the actual affected surface, not borrowed from a plaque model.

What does this change for translational dermatology?

Two practical moves.

First, the model enables testing of PPARα agonists and STAT3 inhibitors against PPP directly. PPP is clinically distinct from plaque psoriasis. It responds poorly to many plaque-targeted biologics, and it has no FDA-approved targeted therapy. Borrowing models built for plaque psoriasis has produced mixed translational results.

Second, the PPARα-STAT3 axis is druggable today. PPARα agonists have decades of safety data in metabolic and cardiovascular indications. STAT3 inhibitors are advancing in oncology and autoimmunity. Either path offers a candidate for PPP trials — if the human tissue story lines up.

What does the abstract not yet prove?

Single-cohort mouse findings need independent replication, dose-ranging, and human confirmation. STAT3 sits downstream of IL-17, IL-22, and other cytokines implicated in PPP. Untangling cause from consequence will take more than one knockout. And Mettl3 loss is artificial — patients don't delete Mettl3. The model is a tool, not a stand-in for patient biology.

What comes next for the field?

Watch for the full manuscript, for replication by independent groups, and for PPARα and STAT3 readouts in human PPP biopsies. If those hold, expect early translational interest in repurposed metabolic drugs for a pustular disease that has almost no targeted options.