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Gallo RL, Nakatsuji T. Microbial symbiosis with the innate immune defense system of the skin. J Invest Dermatol 2011; 131:1974-80. [PMID: 21697881 PMCID: PMC3174284 DOI: 10.1038/jid.2011.182] [Citation(s) in RCA: 226] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Skin protects itself against infection through a variety of mechanisms. Antimicrobial peptides (AMPs) are major contributors to cutaneous innate immunity, and this system, combined with the unique ionic, lipid and physical barrier of the epidermis is the first line defense against invading pathogens. However, recent studies have revealed that our skin’s innate immune system is not solely of human origin. Staphylococcus epidermidis, a major constituent of the normal microflora on healthy human skin, acts as a barrier against colonization of potentially pathogenic microbes and against overgrowth of already present opportunistic pathogens. Our resident commensal microbes produce their own AMPs, act to enhance the normal production of AMPs by keratinocytes, and are beneficial to maintaining inflammatory homeostasis by suppressing excess cytokine release after minor epidermal injury. These observations indicate that the normal human skin microflora protects skin via various modes of action, a conclusion supported by many lines of evidence associating diseases such as acne, atopic dermatitis, psoriasis and rosacea with an imbalance of the microflora even in the absence of classical infection. This review highlights recent observations on the importance of innate immune systems and the relationship with the normal skin microflora to maintain healthy skin.
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Affiliation(s)
- Richard L Gallo
- Department of Medicine, Division of Dermatology, University of California, San Diego, San Diego, California 92121, USA.
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152
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Khnykin D, Miner JH, Jahnsen F. Role of fatty acid transporters in epidermis: Implications for health and disease. DERMATO-ENDOCRINOLOGY 2011; 3:53-61. [PMID: 21695012 PMCID: PMC3117002 DOI: 10.4161/derm.3.2.14816] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 01/07/2011] [Accepted: 01/13/2011] [Indexed: 12/31/2022]
Abstract
Skin epidermis is an active site of lipid synthesis. The intercellular lipids of human stratum corneum (SC) are unique in composition and quite different from the lipids found in most biological membranes. The three major lipids in the SC are free fatty acids, cholesterol and ceramides. Fatty acids can be synthesized by keratinocytes de novo and, in addition, need to be taken up from the circulation. The latter process has been shown to be protein mediated, and several fatty acid transporters are expressed in skin. Recent studies of transgenic and knockout animal models for fatty acid transporters and the identification of fatty acid transport protein 4 (FATP4 or SLC27A4) mutations as causative for Ichthyosis Prematurity Syndrome highlight the vital roles of fatty acid transport and metabolism in skin homeostasis. This review provides an overview of our current understanding of the role of fatty acids and their transporters in cutaneous biology, including their involvement in epidermal barrier generation and skin inflammation.
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Affiliation(s)
- Denis Khnykin
- Laboratory for Immunohistochemistry and Immunopathology (LIIPAT); Department of Pathology; Oslo University Hospital-Rikshospitalet; Oslo, Norway
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153
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The coordinated response of the physical and antimicrobial peptide barriers of the skin. J Invest Dermatol 2011; 131:285-7. [PMID: 21228809 DOI: 10.1038/jid.2010.360] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Antimicrobial peptides (AMPs) are an essential and multifunctional element for immune defense of the skin during infection and injury. In this issue, Ahrens et al. characterize the response of β-defensins, a class of AMPs, following acute and chronic challenges to the permeability barrier of the skin. Their findings suggest that the antimicrobial and permeability barriers of the skin are closely linked.
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154
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Tzellos T, Zampeli V, Makrantonaki E, Zouboulis CC. Treating acne with antibiotic-resistant bacterial colonization. Expert Opin Pharmacother 2011; 12:1233-47. [PMID: 21355786 DOI: 10.1517/14656566.2011.553192] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Acne is a chronic skin disorder of the pilosebaceous unit; it has a multifactorial pathogenesis. Propionibacterium acnes within the follicle is considered to be a triggering factor of inflammation in acne. Antibiotics have been the primary treatment against P. acnes for more than 40 years. However, a gradual increase in the prevalence of antibiotic-resistant strains of P. acnes has been observed. AREAS COVERED This review discusses the pathophysiology of antibiotic-resistant acne development. It focuses on strategies to minimize the development of resistance and, most importantly, confront the development of antibiotic-resistant acne. The literature search was conducted up to August 2010, using the search terms 'acne', 'antibiotic-resistant acne' and 'bacterial resistance'. EXPERT OPINION Antibiotic-resistant acne is a real phenomenon. Strategies to prevent and confront it should include not only the use of certain treatment regimens but also rational prescribing policies, combination therapies, use of antibacterial non-antibiotic agents and treatment options targeting all the pathogenetic components of acne. Benzoyl-peroxide-based treatment is the most evidence-based approach. Oral isotretinoin remains the most efficacious option for severe acne.
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Affiliation(s)
- Thrasivoulos Tzellos
- Dessau Medical Center, Departments of Dermatology, Venereology, Allergology and Immunology, Auenweg Dessau, Germany.
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155
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Lee SE, Kim JM, Jeong SK, Jeon JE, Yoon HJ, Jeong MK, Lee SH. Protease-activated receptor-2 mediates the expression of inflammatory cytokines, antimicrobial peptides, and matrix metalloproteinases in keratinocytes in response to Propionibacterium acnes. Arch Dermatol Res 2010; 302:745-56. [PMID: 20697725 PMCID: PMC2970807 DOI: 10.1007/s00403-010-1074-z] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2010] [Revised: 07/25/2010] [Accepted: 07/28/2010] [Indexed: 12/22/2022]
Abstract
Propionibacterium acnes (P. acnes) has been known to produce various exogenous proteases, however, their role in acne pathogenesis remains largely unknown. Proteases elicit cellular responses, at least in part, via proteinase-activated receptor-2 (PAR-2), which is known to mediate inflammation and immune response. In this study, we investigated whether proteases from P. acnes could activate PAR-2 on keratinocytes and induce pro-inflammatory cytokines, antimicrobial peptides (AMPs), and matrix metalloproteinases (MMPs) via PAR-2 signaling. We examined PAR-2 expression and protease activity in acne lesions using immunofluorescence staining and in situ zymography. The effect of the culture supernatant of P. acnes on Ca(2+) signaling in immortalized keratinocytes (HaCaT) was measured using a fluorescence method. HaCaT cells were treated with P. acnes strain ATCC 6919 culture supernatant, with or without pretreatment with serine protease inhibitor or selective PAR-2 antagonist and the gene expression of pro-inflammatory cytokines, AMPs, and MMPs was detected using real-time reverse transcription-polymerase chain reaction. We found that the protease activity and PAR-2 expression were increased in acne lesions. The P. acnes culture supernatant induced calcium signaling in keratinocytes via PAR-2 and stimulated the mRNA expression of interleukin (IL)-1α, -8, tumor necrosis factor (TNF)-α, human beta defensin (hBD)-2, LL-37, MMP-1, -2, -3, -9, and -13 in keratinocytes, which was significantly inhibited by serine protease inhibitor as well as selective PAR-2 specific antagonist. These results indicate that PAR-2 plays an important role in the pathogenesis of acne by inducing inflammatory mediators in response to proteases secreted from P. acnes.
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Affiliation(s)
- Sang Eun Lee
- Department of Dermatology, Gangnam Severance Hospital, Yonsei University College of Medicine, 712 Eonjuro, Kangnam-gu, Seoul, 135-720 Korea
- Human Barrier Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Ji-Min Kim
- Department of Dermatology, Gangnam Severance Hospital, Yonsei University College of Medicine, 712 Eonjuro, Kangnam-gu, Seoul, 135-720 Korea
- Human Barrier Research Institute, Yonsei University College of Medicine, Seoul, Korea
- Brain Korea 21 Project for Medical Science, Yonsei University, Seoul, Korea
| | | | | | - Hyun-Ju Yoon
- Technology Support Part, Central Research Laboratories, Aekyung, Taejon, Korea
| | - Min-Kyung Jeong
- Department of Dermatology, Gangnam Severance Hospital, Yonsei University College of Medicine, 712 Eonjuro, Kangnam-gu, Seoul, 135-720 Korea
- Human Barrier Research Institute, Yonsei University College of Medicine, Seoul, Korea
- Brain Korea 21 Project for Medical Science, Yonsei University, Seoul, Korea
| | - Seung Hun Lee
- Department of Dermatology, Gangnam Severance Hospital, Yonsei University College of Medicine, 712 Eonjuro, Kangnam-gu, Seoul, 135-720 Korea
- Human Barrier Research Institute, Yonsei University College of Medicine, Seoul, Korea
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