involucrin and Acne-Vulgaris

Forkhead box-O1 (FoxO1) is a key nutrient- and growth factor-dependent regulator of metabolism, but its functional role in human primary keratinocytes (HPKs) is less known. To investigate the role of FoxO1 in HPKs and effect of insulin-like growth factor 1 (IGF-1) and isotretinoin on FoxO1 expression, HPKs were treated with 1.2 mmol/L calcium chloride, 1-20 ng/mL IGF-1 and 0.1-10 μmol/L isotretinoin. Recombinant adenovirus expressing FoxO1 or FKHR shRNA lentivirus transfection was introduced to upregulate or silence FoxO1 expression. Epidermal FoxO1 immunostaining was lower in acne lesion than in normal skin. FoxO1 overexpression induced involucrin expression, G2/M arrest and apoptosis but suppressed proliferation, while FoxO1 silencing decreased involucrin expression but increased proliferation, S phase and viable cells in HPKs. IGF-1 downregulated FoxO1 and involucrin but upregulated p-Akt expression in HPKs, which was blocked by pretreatment with LY294002. Isotretinoin enhanced FoxO1, p53 and p21 but inhibited p-FoxO1 and involucrin expression in HPKs. These results demonstrate that FoxO1 promotes differentiation and apoptosis in HPKs. IGF-1 may reduce keratinocyte differentiation through PI3K/Akt/FoxO1 pathway, while isotretinoin can reinforce FoxO1 expression. FoxO1 may be involved in acne pathogenesis and could serve as a potential therapeutic target.

Topics: Acne Vulgaris; Apoptosis; Cell Cycle Checkpoints; Cell Differentiation; Cell Proliferation; Cell Survival; Cells, Cultured; Chromones; Dermatologic Agents; Enzyme Inhibitors; Forkhead Box Protein O1; Gene Expression; Gene Silencing; Humans; Insulin-Like Growth Factor I; Isotretinoin; Keratinocytes; Morpholines; Phosphorylation; Primary Cell Culture; Protein Precursors; Proto-Oncogene Proteins c-akt; Signal Transduction; Transfection; Tumor Suppressor Protein p53; Up-Regulation

Propionibacterium acnes is one of the most significant pathogenic factors of acne vulgaris. This bacteria relates to acne by various pathways. It has also been reported that P. acnes influences pro-inflammatory cytokine production in keratinocytes in vitro. However, the influence on the differentiation of keratinocytes by P. acnes has not been studied extensively. We analyzed the expression of keratinocyte differentiation-specific markers, keratins, and pro-inflammatory cytokines in normal human epidermal keratinocytes (NHEK) exposed to P. acnes in vitro. All P. acnes strains used in this study increased transglutaminase (TGase), keratin 17 (K17) and interleukin (IL) mRNA expression levels in NHEK, and decreased K1 and K10 expression levels. Some P. acnes strains increased involucrin and K6 mRNA expression levels in NHEK and decreased filaggrin, K6 and K16 expression levels in vitro. This experiment clarified that P. acnes influences the differentiation of NHEK in vitro. As a result, P. acnes influenced the expression of not only pro-inflammatory cytokines but also some keratinocyte differentiation-specific markers and keratins in NHEK. Our results suggest that P. acnes relates to acne pathogenesis by not only the induction of inflammation but also in the differentiation of keratinocytes. Moreover, it was considered that the reaction of NHEK to P. acnes may be different depending on the type of bacteria.

Topics: Acne Vulgaris; Base Sequence; Cell Differentiation; Cells, Cultured; DNA Primers; Filaggrin Proteins; Gene Expression; Humans; In Vitro Techniques; Interleukins; Intermediate Filament Proteins; Keratinocytes; Keratins; Propionibacterium acnes; Protein Precursors; RNA, Messenger; Transglutaminases

Acne vulgaris is the result of multifactorial disorders of the pilosebaceous duct. The initial lesion is believed to be hyper-keratinization of the infundibulum. The Rhino mouse has been used as an experimental acne model system for screening anti-keratinizing and comedolytic agents. Using this system we show that trypsin could induce desquamation and utriculi-epidermal differentiation in the absence of irritation. Following five daily trypsin treatments, the biomechanical properties of the mouse skin improved, as demonstrated by cutometer measurements and increased elastin expression. Extensive programmed cell death and apoptosis are demonstrated in the utriculi epithelium of the untreated animals. This cell death is eliminated by the trypsin treatment. We speculate that co-administration of trypsin might increase the therapeutic value of topical acne treatments and improve skin elasticity while reducing irritating effects.

Topics: Acne Vulgaris; Animals; Apoptosis; Cricetinae; Disease Models, Animal; Gene Expression; Glyceraldehyde-3-Phosphate Dehydrogenases; Hair Follicle; Keratolytic Agents; Male; Mesocricetus; Mice; Mice, Hairless; Polymerase Chain Reaction; Protein Precursors; RNA, Messenger; Skin; Skin Aging; Trypsin