Malassezia Research Articles

PH-Dependent Expression, Stability, and Activity of Malassezia restricta MrLip5 Lipase.

BackgroundThe lipophilic yeasts Malassezia spp. are normally resident on the surface of the human body, and often associated with various skin diseases. Of the 18 known Malassezia spp., Malassezia restricta is the most predominantly identified Malassezia sp. found on the human skin. Malassezia possesses a large number of genes encoding lipases to degrade human sebum triglycerides into fatty acids, which are required not only for their growth, but also trigger skin diseases. Previously, we have shown that MrLIP5 (MRET_0930), one of the 12 lipase genes in the genome of M. restricta, and is the most frequently expressed lipase gene in the scalp of patients with dandruff.ObjectiveIn this study, we aimed to analyze the activity, stability, and expression of MrLip5, with particular focus on pH.MethodsWe heterologously expressed MrLip5 in Escherichia coli, and purified and analyzed its activity and expression under different pH conditions.ResultsWe found that MrLip5 was most active and stable and highly expressed under alkaline conditions, which is similar to that of the diseased skin surface.ConclusionOur results suggest that the activity and expression of MrLip5 are pH-dependent, and that this lipase may play an essential role at the M. restricta-host interface during disease progression.

Supragingival mycobiome and inter-kingdom interactions in dental caries

ABSTRACT Background: Recent studies have reveled the presence of a complex fungal community (mycobiome) in the oral cavity. However, the role of oral mycobiome in dental caries and its interaction with caries-associated bacteria is not yet clear. Methods: Whole-mouth supragingival plaque samples from 30 children (6–10 years old) with no caries, early caries, or advanced caries were sequenced for internal transcribed spacer 2 (ITS-2). The mycobiome profiles were correlated with previously published bacteriome counterparts. Interaction among selected fungal and bacterial species was assessed by co-culture or spent media experiments. Results: Fungal load was extremely low. Candida, Malassezia, Cryptococcus, and Trichoderma spp. were the most prevalent/abundant taxa. Advanced caries was associated with significantly higher fungal load and prevalence/abundance of Candida albicans. Cryptococcus neoformans and Candida sake were significantly over-abundant in early caries, while Malassezia globosa was significantly enriched in caries-free subjects. C. albicans correlated with Streptococcus mutans and Scardovia wiggsiae among other caries-associated bacteria, while M. globosa inversely correlated with caries-associated bacteria. In-vitro, M. globosa demonstrated inhibitory properties against S. mutans. Conclusions: the results substantiate the potential role of the oral mycobiome, primarily Candida species, in dental caries. Inter-kingdom correlations and inhibition of S. mutans by M. globosa are worth further investigation.

Guinea pig seborrheic dermatitis model of Malassezia restricta and the utility of luliconazole.

Seborrheic dermatitis (SD) is a multifactorial disease in which Malassezia restricta has been proposed as the predominant pathogenic factor. However, experimental evidence supporting this hypothesis is limited. A guinea pig SD model using a clinical isolate of M. restricta was used to elucidate the pathogenicity of M. restricta. Also, the efficacy of 1% luliconazole (LLCZ) cream, a topical imidazole derivative, against M. restricta was compared with that of a 2% ketoconazole (KCZ) cream in the same guinea pig model. Dorsal skin hairs of guinea pig were clipped and treated with M. restricta by single or repeated inoculations without occlusion. Skin manifestations were examined macroscopically and histologically. A quantitative polymerase chain reaction (PCR) assay was also performed for mycological evaluation. An inflammatory response mimicking SD occurred after repeated as well as single inoculation but not in abraded skin. The inflammation score attained its maximum on day 11 and persisted until day 52. The yeast form of the fungal elements was distributed on the surface of stratum corneum and around the follicular orifices, and an epidermal and dermal histological reaction was observed. Application of 1% LLCZ or 2% KCZ cream significantly improved the skin manifestations and decreased the quantity of M. restricta rDNA in the skin lesions. The efficacy of topical antifungal drugs suggested that M. restricta is a pathogenic factor contributing to SD.

Fungal involvement (Pityrosporum) in ocular allergy

AbstractAllergic conjunctivitis to atmospheric molds is well documented, Alternaria being by far the most common. However, the role of microbiota fungi in conjunctivitis is less documented. Several old reports until the seventies have underlined the implication of allergy to Candida albicans in some chronic conjunctivitis. Pityrosporum orbiculare allergy has been well documented in head and neck atopic dermatitis in adults, but there is no report showing the involvement of this fungi in chronic conjunctivitis, even if some authors suspected his involvement in blepharitis. Here we describe some case‐reports of atopic keratoconjunctivitis associated with IgE sensitization to Pityrosporum in adults with seborrheic dermatitis or head and neck dermatitis. Patients was initially treated by ciclosporin since no sensitization to aeroallergens have been highlighted. After local and systemic anti‐fungal treatment, ciclosporin was stopped and sustained improvement was observed under discontinuous treatment. When no sensitization to aeroallergens has been highlighted in atopic keratoconjunctivitis, we suggest to seek for sensitization to microbiota fungi particularly Pityrosporum spp. and Candida a. in patients with head skin lesions.

Fungal and bacterial diversity of Svalbard subglacial ice

The composition of fungal and bacterial communities in three polythermal glaciers and associated aquatic environments in Kongsfjorden, Svalbard was analysed using a combination of cultivation and amplicon sequencing. 109 fungal strains belonging to 30 mostly basidiomycetous species were isolated from glacial samples with counts up to 103 CFU/100 ml. Glaciozyma-related taxon and Phenoliferia psychrophenolica were the dominant species. Unexpectedly, amplicon sequencing uncovered sequences of Chytridiomycota in all samples and Rozellomycota in sea water, lake water, and tap water. Sequences of Malassezia restricta and of the extremely halotolerant Hortaea werneckii were also found in subglacial habitats for the first time. Overall, the fungal communities within a glacier and among glaciers were diverse and spatially heterogenous. Contrary to this, there was a large overlap between the bacterial communities of different glaciers, with Flavobacterium sp. being the most frequently isolated. In amplicon sequencing Actinobacteria and Proteobacteria sequences were the most abundant.

Longitudinal study of the bacterial and fungal microbiota in the human sinuses reveals seasonal and annual changes in diversity

There is a pressing need for longitudinal studies which examine the stability of the sinonasal microbiota. In this study, we investigated bacterial and fungal community composition of the sinuses of four healthy individuals every month for one year, then once every three months for an additional year to capture seasonal variation. Sequencing of bacterial 16S rRNA genes and fungal ITS2 revealed communities that were mainly dominated by members of Actinobacteria and Basidiomycota, respectively. We observed overall shifts in both bacterial and fungal community diversity that were attributable to a combination of individual, seasonal and annual changes. The results suggest that each of the subjects possessed a strong bacterial sinonasal signature, but that fungal communities were less subject specific. Differences in fungal and bacterial diversity between subjects, and which OTUs may be correlated with seasonal differences, were investigated. A small core community that persisted throughout the two year sampling period was identified: Corynebacterium, Propionibacterium and Staphylococcus, and one type of fungus, Malassezia restricta. It is likely that bacterial and fungal airway microbiomes are dynamic and experience natural shifts in diversity with time. The underlying reasons for these shifts appear to be a combination of changes in environmental climate and host factors.

ANÁLISES DE QUALIDADE DE XAMPUS DE CETOCONAZOL 2% MANIPULADOS EM FARMÁCIAS MAGISTRAIS DE PORTO VELHO, RO, BRASIL

Os xampus são produtos para a limpeza ou fixação de substâncias com ação dermatológica. Xampus de Cetoconazol têm a finalidade de tratar e prevenir infecções fúngicas causadas por Malassezia globosa. Por serum xampu de alto consumo pela população, faz-se necessária a confirmação da qualidade dos produtos manipulados nas farmácias magistrais. O objetivo deste trabalho foi realizar análises de qualidade dos xampus de cetoconazol manipulados em farmácias magistrais de Porto Velho, RO. Foram realizadas análises organolépticas,potencial hidrogeniônico (pH), determinação da densidade, viscosidade, potencial espumante, teste de centrifugação e doseamento espectrofotométrico. Após analisar as cinco amostras manipuladas todas foram satisfatórias quanto à análise organoléptica; em relação ao pH, apenas a amostra B mostrou-se dentro dos padrões. Na determinação da densidade, as amostras A e C se mostraram satisfatórias. Quanto àviscosidade, apenas a E se mostrou insatisfatória; o poder espumante e o doseamento não foi aceitável para as amostras D e E. No teste de centrifugação, as formulações A, D e E formaram precipitados.

Identification of yeasts present in artisanal yoghurt and traditionally fermented milks consumed in the northern part of Cameroon

Abstract Bacteria generally ferment milk but, sometimes, yeasts are found in fermented milks. The presence of these yeasts in the microbial community of some fermented milks could be intentional or accidental. The Diversity of yeasts in the products was investigated using a molecular technique employing variable regions of 26S rDNA profiles generated by PCR-DGGE (Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis). Two types of samples: artisanal or handcraft yoghurt and traditionally fermented milks were collected in three towns of the three regions of the northern part of Cameroon. Firstly, a comparison was made between the 16 traditionally fermented milks collected in Maroua, Garoua and Ngaoundre each of the 3 regions. Secondly, it was between 26 artisanal fermented milks of each region and finally, between the two types of products. The different PCR-DGGE 26S rDNA profiles obtained were analyzed and DNA sequencing was used to compare yeasts from each method of production. Twelve (12) species of Yeasts were identified as: Malassezia globosa, Hanseniaspora uvarum, Galactomyces candidum, Candida tropicalis, Aureobasidium pullulans, Torulaspora globosa, Saccharomyces cerevisiae/paradoxus, Pichia kluyveri, Candida parapsilosis, Torulaspora delbrueckii, Kluyveromyces marxianus, Candida orthopsilosis and Pseudozyma sp. Yeast diversity was higher for artisanal fermented milks (yoghurt) with at least 10 species, while for traditionally non packed fermented milks only 5 species were identified with a predominance strain of Galactomyces candidum, Candida parapsilosis, Torulaspora delbrueckii, Saccharomyces cerevisiae/paradoxus and Kluyveromyces marxianus. The different species of yeast might be introduced accidentally in artisanal yoghurt; however, for traditionally fermented milks their presence might be associated to the starter.

Anion Inhibition Profile of the β-Carbonic Anhydrase from the Opportunist Pathogenic Fungus Malassezia Restricta Involved in Dandruff and Seborrheic Dermatitis.

Carbonic anhydrases (CAs, EC 4.2.1.1) are ubiquitous metalloenzymes, which catalyze the crucial physiological CO2 hydration/dehydration reaction (CO2 + H2O ⇌ HCO3− + H+) balancing the equilibrium between CO2, H2CO3, HCO3− and CO32−. It has been demonstrated that their selective inhibition alters the equilibrium of the metabolites above affecting the biosynthesis and energy metabolism of the organism. In this context, our interest has been focalized on the fungus Malassezia restricta, which may trigger dandruff and seborrheic dermatitis altering the complex bacterial and fungal equilibrium of the human scalp. We investigated a rather large number of inorganic metal-complexing anions (a well-known class of CA inhibitors) for their interaction with the β-CA (MreCA) encoded by the M. restricta genome. The results were compared with those obtained for the two human α-CA isoforms (hCAI and hCAII) and the β-CA from Malassezia globosa. The most effective MreCA inhibitors were diethyldithiocarbamate, sulfamide, phenyl arsenic acid, stannate, tellurate, tetraborate, selenocyanate, trithiocarbonate, and bicarbonate. The different KI values obtained for the four proteins investigated might be attributed to the architectural features of their catalytic site. The anion inhibition profile is essential for better understanding the inhibition/catalytic mechanisms of these enzymes and for designing novel types of inhibitors, which may have clinical applications for the management of dandruff and seborrheic dermatitis.

Molecular detection of fungal and bacterial DNA from pustules in patients with palmoplantar pustulosis: special focus on Malassezia species.

Palmoplantar pustulosis (PPP) is a distinct, chronic skin disorder characterized by intraepidermal pustules on the palms and soles. It is hypothesized that microorganisms on the skin might induce the symptoms of PPP via inflammatory cell activation. However, the microbiota has not been studied in detail because of the assumption that the pustules in PPP are sterile. To elucidate the role of microorganisms in pathogenesis of PPP. PCR analysis was performed of microbial DNA fragments in the pustules of patients with PPP. The sequence of the D1/D2 LSU 26s rRNA gene and that of the 16S rRNA gene was used for fungal and bacterial DNA detection, respectively. In total, 71 samples were carefully collected from the pustules of patients with PPP. Fungal DNA bands were detected in 68 samples, and fungi including Malassezia spp. were identified in 30 of 71 samples (42.3%). Malassezia restricta was the most frequently encountered fungus (14/71; 19.7%). However, bacterial DNA was not detected by the methods used. Furthermore, identical fungal DNA was not detected in the outer lid of the pustules, suggesting that the fungi detected within the pustule did not derive from contamination via the skin surface. In the present study, we demonstrated for the first time that certain pustules in patients with PPP contain fungal DNA fragments, especially those of Malassezia spp. Our findings provide new insights on the role of skin microbiota in the pathogenesis of PPP.

Cloning, Purification, and Characterization of a β-Carbonic Anhydrase from Malassezia restricta, an Opportunistic Pathogen Involved in Dandruff and Seborrheic Dermatitis.

The cloning, purification, and initial characterization of the β-carbonic anhydrase (CA, EC 4.2.1.1) from the genome of the opportunistic pathogen Malassezia restricta (MreCA), which a fungus involved in dandruff and seborrheic dermatitis (SD), is reported. MreCA is a protein consisting of 230 amino acid residues and shows high catalytic activity for the hydration of CO2 into bicarbonate and protons, with the following kinetic parameters: kcat of 1.06 × 106 s−1 and kcat/KM of 1.07 × 108 M−1 s−1. It is also sensitive to inhibition by the sulfonamide acetazolamide (KI of 50.7 nM). Phylogenetically, MreCA and other CAs from various Malassezia species seem to be on a different branch, distinct from that of other β-CAs found in fungi, such as Candida spp., Saccharomyces cerevisiae, Aspergillus fumigatus, and Sordaria macrospora, with only Cryptococcus neoformans and Ustilago maydis enzymes clustering near MreCA. The further characterization of this enzyme and the identification of inhibitors that may interfere with its life cycle might constitute new strategies for fighting dandruff and SD.

Comparison of fluorescent staining versus KOH wet-mount microscopy for detection of superficial fungal infection

Objective To compare the diagnostic value of fluorescent staining versus KOH wet-mount microscopy in detecting superficial fungal infection. Methods Totally, 600 specimens from cases of clinically diagnosed superficial fungal infections and 102 from cases of clinically diagnosed Malassezia infection (including 54 cases of pityriasis versicolor and 48 cases of Malassezia folliculitis) were collected from the dermatology clinic of Tenth People′s Hospital of Tongji University between July 2017 and February 2018. These specimens were subjected to fluorescent staining and KOH wet mount separately followed by direct microscopy, and the positive rate and average time for slide reading were compared between the two methods. Culture served as the gold standard method, and the missed diagnosis rate was compared between the two methods. Statistical analysis was carried out using chi-square test or Fisher′s exact test for comparing enumeration data, and paired t test for comparing emeasurement data. Results Of the 600 specimens from clinically diagnosed superficial fungal infection cases, fungi were detected in 546 (91.00%) and 489 (81.50%) by fluorescent staining and KOH wet-mount microscopy respectively (χ2 = 22.83, P 0.05) , with the average reading time being 38.36 ± 8.79 s and 41.25 ± 15.67 s respectively (t = 1.14, P > 0.05) . Of the 48 specimens from Malassezia infection cases, 43 (89.58%) and 11 (22.92%) specimens were detected to be positive for fungi by fluorescent staining and KOH wet-mount microscopy respectively (χ2 = 43.34, P < 0.05) , and fluorescent staining showed shorter average reading time (42.14 ± 12.61 s) compared with KOH wet-mount microscopy (103.56 ± 9.48 s, t = 17.83, P < 0.05) . Among the 600 specimens from superficial fungal infection cases, culture yielded fungi in 479. Moreover, 476 specimens were found positive by fluorescent staining, and 3 were found negative (0.63%) , while KOH wet-mount microscopy showed 465 positive results and 14 negative results (2.92%) . There was a significant difference in the missed diagnosis rate between the two methods (χ2 = 7.25, P < 0.05) . Conclusion Compared with KOH wet-mount microscopy, fluorescent staining can increase the detection rate, reduce missed diagnosis rate and shorten reading time. Key words: Tinea; Tinea versicolor; Malassezia; Clinical laboratory techniques; Fluorescent staining; KOH method

Important skin microbiota associated with the occurrence of acne

Skin microbiota begin to form shortly after birth, with a wide variety and huge quantity, and are closely related to skin health. Acne is a common skin disorder associated with microbial infections. Propionibacterium acnes, Staphylococcus, Malassezia, etc., are three species of microorganisms currently known to be most closely associated with the occurrence of acne. This review summarizes the relationship between the above three species of microorganisms and the occurrence of acne, and mainly includes the pathogenicity of bacteria or fungi of different types, the relationship between these bacteria or fungi and the pathogenesis of acne, the difference in host immune responses induced by these bacteria or fungi, so as to provide evidence for developing new strategies for the treatment of acne. Key words: Acne vulgaris; Microbial consortia; Propionibacterium acnes; Staphylococcus; Malassezia

In vitro efficacy of antifungal agents alone and in shampoo formulation against dandruff‐associated Malassezia spp. and Staphylococcus spp.

Dandruff is a complex skin condition characterized by unpleasant itching and flaking of the scalp. It is primarily attributed to the over colonization of Malassezia yeasts such as Malassezia globosa and Malassezia restricta. Some studies also suggest the involvement of staphylococci bacteria in dandruff disease pathogenesis. We aimed to access the effectiveness of anti-dandruff treatments by determining the efficacy of the active antifungal agents alone or in commercial shampoo formulations against Malassezia and Staphylococcus. The minimum inhibitory concentrations of three anti-dandruff shampoo antifungals (zinc pyrithione, ketoconazole and ciclopirox) and the witch hazel extract, hamamelitannin were tested against commensal Malassezia and Staphylococcus species using broth microdilution methods. In experiments simulating shampoo exposure and washing conditions on the scalp, we also tested the ability of the above agents in shampoo formulation (Head and Shoulders® (H&S), Ketomed® , Sebiprox® , Erol Healthcare Hair Shampoo® respectively) along with a generic over-the-shelf shampoo to inhibit microbial growth. Ketomed® and H&S shampoo were the most effective treatments against Malassezia in invitro assays and washing simulation experiments. Erol Healthcare Hair Shampoo® was less effective against Malassezia as it required a longer contact time to achieve growth inhibition for some species. Sebiprox® showed variable efficacy in washing and contact time experiments whereas the generic over-the-shelf shampoo was the least effective in inhibiting Malassezia and Staphylococcus growth. From these findings, it is reasonable that patients with dandruff may benefit from applying specific antifungal shampoo although results may vary with microbial species, time of contact and shampoo formulation components.

Antifungal Mechanism of Action of Lauryl Betaine Against Skin-Associated Fungus Malassezia restricta

Betaine derivatives are considered major ingredients of shampoos and are commonly used as antistatic and viscosity-increasing agents. Several studies have also suggested that betaine derivatives can be used as antimicrobial agents. However, the antifungal activity and mechanism of action of betaine derivatives have not yet been fully understood. In this study, we investigated the antifungal activity of six betaine derivatives against Malassezia restricta, which is the most frequently isolated fungus from the human skin and is implicated in the development of dandruff. We found that, among the six betaine derivatives, lauryl betaine showed the most potent antifungal activity. The mechanism of action of lauryl betaine was studied mainly using another phylogenetically close model fungal organism, Cryptococcus neoformans, because of a lack of available genetic manipulation and functional genomics tools for M. restricta. Our genome-wide reverse genetic screening method using the C. neoformans gene deletion mutant library showed that the mutants with mutations in genes for cell membrane synthesis and integrity, particularly ergosterol synthesis, are highly sensitive to lauryl betaine. Furthermore, transcriptome changes in both C. neoformans and M. restricta cells grown in the presence of lauryl betaine were analyzed and the results indicated that the compound mainly affected cell membrane synthesis, particularly ergosterol synthesis. Overall, our data demonstrated that lauryl betaine influences ergosterol synthesis in C. neoformans and that the compound exerts a similar mechanism of action on M. restricta.

Implicating Dysbiosis of the Gut Fungal Microbiome in Uveitis, an Inflammatory Disease of the Eye.

In this study, the gut fungal microbiome of uveitis (UVT) patients was generated and compared with healthy controls (HC) to identify dysbiosis in UVT patients and ascertain the role of gut fungal microbiome in disease pathology. In the present study, gut fungal microbiomes were analyzed in the fecal samples of HC (n = 24) and UVT patients (n = 14) using high-throughput Illumina sequencing of ITS2 region of the fungal ribosomal RNA. QIIME and R software were used for data analysis. The gut fungal richness and diversity were significantly decreased in UVT patients compared to HC. Our analyses showed enrichment of several pathogenic fungi including Malassezia restricta, Candida albicans, Candida glabrata, and Aspergillus gracilis in UVT patients. Heatmap and discriminatory OTUs further confirmed the disparities between UVT and HC microbiomes. This is the first study demonstrating dysbiosis in the gut fungal communities of UVT patients indicating the importance of fungal microbiome in the disease pathology. These initial findings might warrant further investigation into the fungal microbiome, especially interactions between fungal and bacterial that then might give further insight into how probiotics or fecal transplants might benefit.

Dysbiosis of Skin Microbiota in Psoriatic Patients: Co-occurrence of Fungal and Bacterial Communities.

Psoriasis is a chronic inflammatory skin disease, whose pathogenesis involves dysregulated interplay among immune cells, keratinocytes and environmental triggers, including microbiota. Bacterial and fungal dysbiosis has been recently associated with several chronic immune-mediated diseases including psoriasis. In this comprehensive study, we investigated how different sampling sites and methods reflect the uncovered skin microbiota composition. After establishing the most suitable approach, we further examined correlations between bacteria and fungi on the psoriatic skin. We compared microbiota composition determined in the same sample by sequencing two distinct hypervariable regions of the 16S rRNA gene. We showed that using the V3V4 region led to higher species richness and evenness than using the V1V2 region. In particular, genera, such as Staphylococcus and Micrococcus were more abundant when using the V3V4 region, while Planococcaceae, on the other hand, were detected only by the V1V2 region. We performed a detailed analysis of skin microbiota composition of psoriatic lesions, unaffected psoriatic skin, and healthy control skin from the back and elbow. Only a few discriminative features were uncovered, mostly specific for the sampling site or method (swab, scraping, or biopsy). Swabs from psoriatic lesions on the back and the elbow were associated with increased abundance of Brevibacterium and Kocuria palustris and Gordonia, respectively. In the same samples from psoriatic lesions, we found a significantly higher abundance of the fungus Malassezia restricta on the back, while Malassezia sympodialis dominated the elbow mycobiota. In psoriatic elbow skin, we found significant correlation between occurrence of Kocuria, Lactobacillus, and Streptococcus with Saccharomyces, which was not observed in healthy skin. For the first time, we showed here a psoriasis-specific correlation between fungal and bacterial species, suggesting a link between competition for niche occupancy and psoriasis. However, it still remains to be elucidated whether observed microbial shift and specific inter-kingdom relationship pattern are of primary etiological significance or secondary to the disease.

Malassezia restricta plays CARDs in the gut.

This study shows that Malassezia restricta in the gut acts via CARD9S12N, a risk factor for Crohn’s disease, to promote the production of inflammatory cytokines in myeloid phagocytes and exacerbate colitis.

Malassezia Is Associated with Crohn’s Disease and Exacerbates Colitis in Mouse Models

Inflammatory bowel disease (IBD) is characterized by alterations in the intestinal microbiota and altered immuneresponses to gut microbiota. Evidence is accumulating that IBD is influenced by not only commensal bacteria but also commensal fungi. We characterized fungi directly associated with the intestinalmucosa in healthy people and Crohn's disease patients and identified fungi specifically abundant in patients. One of these, the common skin resident fungus Malassezia restricta, is also linked to the presence of an IBD-associated polymorphism in the gene for CARD9, a signaling adaptor important for anti-fungal defense. M.restricta elicits innate inflammatory responses largely through CARD9 and is recognized by Crohn's disease patient anti-fungal antibodies. This yeast elicits strong inflammatory cytokine production from innate cells harboring the IBD-linked polymorphism in CARD9 and exacerbates colitis via CARD9 in mouse models of disease. Collectively, these results suggest that targeting specific commensal fungi may be a therapeutic strategy for IBD.

Identification and Evaluation of Inhibitors of Lipase from Malassezia restricta using Virtual High-Throughput Screening and Molecular Dynamics Studies

Recent studies revealed the role of lipase in the pathogenicity of Malassezia restricta in dandruff and seborrheic dermatitis (D/SD). The lipase from M. restricta (Mrlip1) is considered a potential target for dandruff therapy. In this work, we performed structure-based virtual screening in Zinc database to find the natural bioactive inhibitors of Mrlip1. We identified three compounds bearing superior affinity and specificity from the Traditional Chinese Medicine database (~60,000 compounds), and their binding patterns with Mrlip1 were analyzed in detail. Additionally, we performed three sets of 100 ns MD simulations of each complex in order to understand the interaction mechanism of Mrlip1 with known inhibitor RHC80267 and the newly identified compounds such as ZINC85530919, ZINC95914464 and ZINC85530320, respectively. These compounds bind to the active site cavity and cause conformational changes in Mrlip1. The Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) studies suggested that the average binding energy was stronger in the case of Mrlip1-ZINC85530919 and Mrlip1-ZINC95914464. The selected natural inhibitors might act as promising lead drugs against Mrlip1. Further, the present study will contribute to various steps involved in developing and creating potent drugs for several skin diseases including dandruff.