RESUMEN
Skin identity is controlled by intrinsic features of the epidermis and dermis and their interactions. Modifying skin identity has clinical potential, such as the conversion of residual limb and stump (nonvolar) skin of amputees to pressure-responsive palmoplantar (volar) skin to enhance prosthesis use and minimize skin breakdown. Greater keratin 9 (KRT9) expression, higher epidermal thickness, keratinocyte cytoplasmic size, collagen length, and elastin are markers of volar skin and likely contribute to volar skin resiliency. Given fibroblasts' capacity to modify keratinocyte differentiation, we hypothesized that volar fibroblasts influence these features. Bioprinted skin constructs confirmed the capacity of volar fibroblasts to induce volar keratinocyte features. A clinical trial of healthy volunteers demonstrated that injecting volar fibroblasts into nonvolar skin increased volar features that lasted up to 5 months, highlighting a potential cellular therapy.
Asunto(s)
Refuerzo Biomédico , Bioimpresión , Dermis , Epidermis , Fibroblastos , Queratinocitos , Adulto , Femenino , Humanos , Masculino , Amputados , Diferenciación Celular , Colágeno/metabolismo , Dermis/citología , Dermis/metabolismo , Elastina/metabolismo , Epidermis/metabolismo , Fibroblastos/citología , Fibroblastos/trasplante , Mano , Queratina-9/metabolismo , Queratinocitos/citología , Queratinocitos/metabolismo , Refuerzo Biomédico/métodosRESUMEN
Tissue injury induces metabolic changes in stem cells, which likely modulate regeneration. Using a model of organ regeneration called wound-induced hair follicle neogenesis (WIHN), we identified skin-resident bacteria as key modulators of keratinocyte metabolism, demonstrating a positive correlation between bacterial load, glutamine metabolism, and regeneration. Specifically, through comprehensive multiomic analysis and single-cell RNA sequencing in murine skin, we show that bacterially induced hypoxia drives increased glutamine metabolism in keratinocytes with attendant enhancement of skin and hair follicle regeneration. In human skin wounds, topical broad-spectrum antibiotics inhibit glutamine production and are partially responsible for reduced healing. These findings reveal a conserved and coherent physiologic context in which bacterially induced metabolic changes improve the tolerance of stem cells to damage and enhance regenerative capacity. This unexpected proregenerative modulation of metabolism by the skin microbiome in both mice and humans suggests important methods for enhancing regeneration after injury.
Asunto(s)
Glutamina , Folículo Piloso , Animales , Humanos , Ratones , Glutamina/metabolismo , Queratinocitos , Regeneración , Piel/metabolismo , Cicatrización de Heridas , MicrobiotaRESUMEN
Environmental factors that enhance regeneration are largely unknown. The immune system and microbiome are attributed roles in repairing and regenerating structure but their precise interplay is unclear. Here, we assessed the function of skin bacteria in wound healing and wound-induced hair follicle neogenesis (WIHN), a rare adult organogenesis model. WIHN levels and stem cell markers correlate with bacterial counts, being lowest in germ-free (GF), intermediate in conventional specific pathogen-free (SPF), and highest in wild-type mice, even those infected with pathogenic Staphylococcus aureus. Reducing skin microbiota via cage changes or topical antibiotics decreased WIHN. Inflammatory cytokine IL-1ß and keratinocyte-dependent IL-1R-MyD88 signaling are necessary and sufficient for bacteria to promote regeneration. Finally, in a small trial, a topical broad-spectrum antibiotic also slowed skin wound healing in adult volunteers. These results demonstrate a role for IL-1ß to control morphogenesis and support the need to reconsider routine applications of topical prophylactic antibiotics.