The World’s First Acne Dysbiosis-like Model of Human 3D Ex Vivo Sebaceous Gland Colonized with Cutibacterium acnes and Staphylococcus epidermidis

Abstract

Acne-prone skin is associated with dysbiosis involving Cutibacterium acnes (C. acnes) and Staphylococcus epidermidis (S. epidermidis) causing increased seborrhea in sebaceous glands (SG) and inflammation. Human primary sebocytes were cultivated using 1.106 UFC/mL C. acnes Type IA (facial acne, ATCC6919) and/or 1.105 UFC/mL S. epidermidis (unknown origin, ATCC12228) for 48 h in our SEB4GLN-optimized media without antibiotics. Bacteria and sebocytes were enumerated and assessed to determine their viability. Lipid production was imaged and quantified via Nile Red staining. SG with hair follicles were microdissected from healthy skin and cultured using 1.105 UFC/mL C. acnes Type 1A and/or 1.104 UFC/mL S. epidermidis (wild-type facial skin strain) through prior fixation and immunostaining for MC5R, C. acnes and nuclei (DAPI) via Z-stack confocal microscopy bioimaging (Leica SP5X & FIJI software, Version 2.9.0). C. acnes growth was not impacted when co-cultivated with sebocytes (2D) or SG (3D) models. Phylotype IA stimulated sebocyte lipid production, which had no impact on viability. The S. epidermidis reference strain overproliferated, inducing sebocyte mortality. For 3D SG model, culture conditions were optimized using a wild-type facial skin strain at a lower concentration, 1:10 ratio to C. acnes, reduced contact time, sequential inoculation and rinsing step. Bioimaging revealed strong C. acnes labeling in the active areas of the pilosebaceous unit. S. epidermidis formed biofilm, which was distributed across the SG via non-specific fluorescence imaging. We developed an innovative model of a sebaceous gland that mimics acne-prone skin with lipid overproduction and virulent phylotype IA C. acnes inoculation.