A Negative Regulatory Mechanism Involving 14-3-3ζ Limits Signaling Downstream of ROCK to Regulate Tissue Stiffness in Epidermal Homeostasis

ROCK signaling causes epidermal hyper-proliferation by increasing ECM production, elevating dermal stiffness, and enhancing Fak-mediated mechano-transduction signaling. Elevated dermal stiffness in turn causes ROCK activation, establishing mechano-reciprocity, a positive feedback loop that can promote tumors. We have identified a negative feedback mechanism that limits excessive ROCK signaling during wound healing and is lost in squamous cell carcinomas (SCCs). Signal flux through ROCK was selectively tuned down by increased levels of 14-3-3ζ, which interacted with Mypt1, a ROCK signaling antagonist. In 14-3-3ζ−/− mice, unrestrained ROCK signaling at wound margins elevated ECM production and reduced ECM remodeling, increasing dermal stiffness and causing rapid wound healing. Conversely, 14-3-3ζ deficiency enhanced cutaneous SCC size. Significantly, inhibiting 14-3-3ζ with a novel pharmacological agent accelerated wound healing 2-fold. Patient samples of chronic non-healing wounds overexpressed 14-3-3ζ, while cutaneous SCCs had reduced 14-3-3ζ. These results reveal a novel 14-3-3ζ-dependent mechanism that negatively regulates mechano-reciprocity, suggesting new therapeutic opportunities. [Display omitted] •14-3-3ζ deficiency or inhibition enhances signaling flux through ROCK•Increased signaling via ROCK boosts mechano-reciprocity, accelerating wound healing•14-3-3ζ binds Mypt1, promoting its function and enhancing pMlc dephosphorylation•14-3-3ζ deficiency increases tumor size ROCK signaling increases dermal stiffness by inside-out mechanical signaling. Resulting integrin ligation further activates ROCK by outside-in signaling, establishing a mechano-reciprocal vicious cycle. Kular, Scheer et al. show that in a negative feedback mechanism, 14-3-3ζ limits ROCK signaling in the skin and moderates mechano-reciprocity, with implications for healing and cancer.