Work

Characteristics of Malassezia furfur at various pH and effects of Malassezia lipids on skin cells

Year: 2024

Type: article

Abstract: The skin, the largest organ in the human body, consisting of the epidermis, dermis, hair follicles, sweat glands, sebaceous glands, and fat layer, performs important physical barrier dynamics that protect the interior from various external environmental factors (de Szalay and Wertz 2023 ; Lai-Cheong and McGrath 2013 ). Most notably, when exposed to ultraviolet (UV) rays, the skin naturally produces a pigment called melanin to protect itself from the harmful rays (Brenner and Hearing 2008 ). It also plays an essential role in preventing harmful chemicals from entering the body through mechanical impacts or scratches, which can lead to skin diseases (Hänel et al. 2013 ). Interestingly, our skin, especially the epidermis, is home to various bacteria, fungi, and viruses that live in symbiosis and form a biological barrier called the skin microbiome (Grice and Segre 2011 ). Their role is to protect the skin by preventing the colonization of harmful pathogens that may invade from the outside and participating in the differentiation and regeneration of skin cells. They also positively impact skin health and immunity by producing beneficial substances or inducing the host to produce antimicrobial substances. Sometimes, an imbalance between these microorganisms can occur due to various environmental factors, causing a breakdown of the skin barrier (Harris-Tryon and Grice 2022 ). This altered host response can lead to skin diseases such as dermatitis, psoriasis, seborrheic dermatitis, alopecia areata, acne, and in the worst cases skin cancer (De Pessemier et al. 2021 ; Gaitanis et al. 2008 ). Therefore, research is actively underway to identify the composition of the skin microbiome, the centerpiece of the skin barrier, to prevent and treat various skin diseases and to positively affect the skin. In particular, the development of next-generation sequencing (NGS) technology has led to significant advances in research by fundamentally revealing the composition of the human microbiome. The traditional method of identifying microorganisms is to take skin cells from a specific location and perform actual cultures. This method has a major limitation in identifying microorganisms when culture is not possible due to complex culture conditions or the inability to realize realistic growth conditions. However, NGS technology has overcome these limitations by using microbial DNA extracted from samples rather than cultures, and it also allows us to determine their relative distribution (Hodkinson and Grice 2015 ). The human microbiome project, which aims to characterize human microorganisms based on NGS, has found that the microbiome of the body can be broadly divided into dry, moist, toenail, and sebaceous areas. In addition, it was revealed that the relative abundance of microorganisms coexisting in each area differs depending on the environment of the body part. As a result, in contrast to the rich bacterial diversity present in each skin region, the fungi present in the sebaceous areas of most skin, except two web space including toenails and plantar heels, were identified as belonging to the Malassezia genus, which have lipophilic properties (Byrd et al. 2018 ; Grice and Segre 2011 ). Although the Malassezia genus is a resident flora in the skin, it is also known as an opportunistic infectious agent due to its prevalence in dermatologic lesions such as seborrheic dermatitis, dandruff, alopecia, atopic dermatitis, and pityriasis versicolor (Huang et al. 2019 ; Park et al. 2021 ).

Source: Applied Microbiology and Biotechnology

DOI: 10.1007/s00253-024-13292-2