The grease trap: uncovering the mechanism of the hydrophobic lid in Cutibacterium acnes lipase

New insights into the role of Cutibacterium acnes-derived extracellular vesicles in inflammatory skin disorders

Cutibacterium acnes (C. acnes) is one of the most prevalent bacteria that forms the human skin microbiota. Specific phylotypes of C. acnes have been associated with the development of acne vulgaris, while other phylotypes have been linked to healthy skin. In this scenario, bacterial extracellular vesicles (EVs) play a role in the interkingdom communication role with the human host. The purpose of this study was to examine the impact of EVs generated by various phylotypes of C. acnes on inflammation and sebum production using different in vitro skin cell types. The main findings of this study reveal that the proteomic profile of the cargo embodied in the EVs reflects distinct characteristics of the different C. acnes phylotypes in terms of life cycle, survival, and virulence. The in vitro skin cell types showed an extended pro-inflammatory modulation of SLST A1 EVs consistently triggering the activation of the inflammation-related factors IL-8, IL-6, TNFα and GM-CSF, in comparison to SLST H1 and SLST H2. Additionally, an acne-prone skin model utilizing PCi-SEB and arachidonic acid as a sebum inducer, was employed to investigate the impact of C. acnes EVs on sebum regulation. Our findings indicated that all three types of EVs significantly inhibited sebum production after a 24-h treatment period, with SLST H1 EVs exhibiting the most pronounced inhibitory effect when compared to the positive control. The results of this study highlight the protective nature of C. acnes SLST H1 EVs and their potential use as a natural treatment option for alleviating symptoms associated with inflammation and oily skin.

Bioprospecting the Skin Microbiome: Advances in Therapeutics and Personal Care Products

Bioprospecting is the discovery and exploration of biological diversity found within organisms, genetic elements or produced compounds with prospective commercial or therapeutic applications. The human skin is an ecological niche which harbours a rich and compositional diversity microbiome stemming from the multifactorial interactions between the host and microbiota facilitated by exploitable effector compounds. Advances in the understanding of microbial colonisation mechanisms alongside species and strain interactions have revealed a novel chemical and biological understanding which displays applicative potential. Studies elucidating the organismal interfaces and concomitant understanding of the central processes of skin biology have begun to unravel a potential wealth of molecules which can exploited for their proposed functions. A variety of skin-microbiome-derived compounds display prospective therapeutic applications, ranging from antioncogenic agents relevant in skin cancer therapy to treatment strategies for antimicrobial-resistant bacterial and fungal infections. Considerable opportunities have emerged for the translation to personal care products, such as topical agents to mitigate various skin conditions such as acne and eczema. Adjacent compound developments have focused on cosmetic applications such as reducing skin ageing and its associated changes to skin properties and the microbiome. The skin microbiome contains a wealth of prospective compounds with therapeutic and commercial applications; however, considerable work is required for the translation of in vitro findings to relevant in vivo models to ensure translatability.

Identification of natural inhibitors to inhibit C. acnes lipase through docking and simulation studies

Acne vulgaris is a common skin disease affecting 80-90% of teenagers worldwide. C. acnes producing lipases are the main virulence factor that catalyzes sebum lipid into free fatty acid that is used for C. acnes growth. Recently, computational biology and bioinformatics play a significant role in drug discovery programs and the identification of novel lead(s). In this study, potential inhibitors against the C. acnes lipase have been identified via cost-effective computational investigations. Molecular docking, MD simulations, and binding affinity analysis have been performed between the active site of C. acnes lipase protein and selected natural plant constituents. First, C. acnes lipase protein was downloaded from PDB and defined the catalytically active site. Next, 16 active natural plant constituents were shortlisted from the PubChem library (based on their pharmacokinetics, pharmacodynamics, and antibacterial activity). Docking studies identified the best five active compounds that showed significantly strong binding affinity interacted through hydrogen bonding, hydrophobic interactions, and π-stacking with the active site residues of the target protein. Furthermore, a 100 ns MD simulation run showed a stable RMSD and less fluctuating RMSF graph for luteolin and neryl acetate. In silico investigation suggested that luteolin, neryl acetate, and isotretinoin were involved in stable interactions which were maintained throughout the MD run with the C. acnes lipase enzyme, virtually. The results advocated that these could potentially inhibit lipase activity and be used in the clinical management of acne.

Action of Mangifera indica Leaf Extract on Acne-Prone Skin through Sebum Harmonization and Targeting C. acnes

(1) Background: Preclinical studies report that the ethanolic fraction from Mangifera indica leaves is a potential anti-acne agent. Nevertheless, the biological activity of Mangifera indica leaves has scarcely been investigated, and additional data are needed, especially in a clinical setting, for establishing the actual effectiveness of Mangifera indica extract as an active component of anti-acne therapy. (2) Methods: The evaluation of the biological activity of Mangifera indica extract was carried out through different experimental phases, which comprised in silico, in vitro, ex vivo and clinical evaluations. (3) Results: In silico and in vitro studies allowed us to identify the phytomarkers carrying the activity of seboregulation and acne management. Results showed that Mangifera indica extract reduced lipid production by 40% in sebocytes, and an improvement of the sebum quality was reported after the treatment in analyses performed on sebaceous glands from skin explants. The evaluation of the sebum quantity and quality using triglyceride/free fatty acid analysis conducted on Caucasian volunteers evidenced a strong improvement and a reduction of porphyrins expression. The C. acnes lipase activity from a severe acne phylotype was evaluated in the presence of Mangifera indica, and a reduction by 29% was reported. In addition, the analysis of the skin microbiota documented that Mangifera indica protected the microbiota equilibrium while the placebo induced dysbiosis. (4) Conclusions: Our results showed that Mangifera indica is microbiota friendly and efficient against lipase activity of C. acnes and supports a role for Mangifera indica in the therapeutic strategy for prevention and treatment of acne.

Comparative Proteomic Analysis of Membrane Vesicles from Clinical C. acnes Isolates with Differential Antibiotic Resistance

Purpose

Cutibacterium acnes (C. acnes) is closely associated with the pathogenesis of acne, and antibiotics targeting C. acnes have been widely used for decades. However, antibiotic resistance has been increasing rapidly. Membrane vesicles (MVs) have been found to play important roles in antibiotic resistance in some bacteria. We aimed to explore the mechanism of antibiotic resistance and the virulence components within C. acnes-derived MVs.

Materials and Methods

We isolated clinical C. acnes strains from the lesions of acne patients who were sensitive or resistant to the antibiotics erythromycin and clindamycin. We analyzed the proteome of MVs from four sensitive C. acnes isolates and three resistant isolates by LC-MS/MS.

Results

We identified 543 proteins within the MVs of clinical C. acnes strains. Several lipases, NlpC/P60, CAMP factor, and Hta domain protein were detected as virulence factors in the C. acnes-derived MVs. The levels of two lipases and FtsZ were significantly higher in resistant C. acnes-derived MVs compared with sensitive strains (p < 0.05).

Conclusion

According to the implications of this study, improper antibiotic use might not only increase antibiotic resistance in C. acnes but could also further alter the cutaneous lipid composition and aggravate host inflammation, thus resulting in worse clinical manifestations in acne patients. This study re-emphasizes that the improper use of antibiotics should be treated more seriously in clinical practice. Furthermore, to combat multidrug resistance in C. acnes, this study suggests that FtsZ inhibitors could be useful.

Aging Associated Changes in the Adult Human Skin Microbiome and the Host Factors That Affect Skin Microbiome Composition

Understanding changes in the skin microbiome and their relationship to host skin factors during aging remains largely unknown. To better understand this phenomenon, we collected samples for metagenomic and host skin factor analyses from forearm, buttock, and facial skin from 158 Caucasian females at 20-24, 30-34, 40-44, 50-54, 60-64, and 70-74 years of age. Metagenomics analysis was performed using 16S rRNA gene sequencing, while host sebocyte gland area, skin lipids, natural moisturizing factors (NMFs) and anti-microbial peptides (AMPs) measurements were also performed. These analyses demonstrated that skin bacterial diversity increased at all the skin sites with increasing age. Of the bacterial genera with average relative abundance of >1%, only Lactobacillus and Cutibacterium demonstrated a significant change (decrease) in abundance at all sampled skin sites with increasing age. Additional bacterial genera demonstrated significant age and site-specific changes in abundance. Analysis of sebocyte area, NMFs, lipids and AMPs demonstrated an age-related decrease in sebocyte area and increases in NMFs/AMPs/skin lipids, all which correlated with changes in specific bacterial genera. In conclusion, the human skin microbiome undergoes age-associated alterations that may reflect underlying age-related changes in cutaneous biology.

Nanotechnology-based formulations toward the improved topical delivery of anti-acne active ingredients

Introduction: Acne vulgaris is a chronic inflammatory skin disorder that affects an extremely concerning percentage of teenagers (ca. 85%), gathering serious negative impacts on the social life and psychological well-being of individuals. Conventional topical formulations for acne show low tolerability and side effects, such as skin irritation, leading to a decrease in the user's adherence to therapy. Nanotechnology-based formulations were developed as new strategies for topical acne management, particularly to overcome the difficulties associated with conventional treatments.Areas covered: This paper presents a critical analysis of reviewed nanosized anti-acne technological strategies, strongly supporting controlled active ingredient release, improved skin permeation, and lower skin irritation. An updated regulatory framework, considering the promising applications in nanomedicine, and the toxicity of these nanosystems are also addressed.Expert opinion: Nanosystems evidence several advantages, attending to the possibility of controlled active ingredient release, better skin permeation, and lower skin irritation. However, novel nanotechnological strategies for acne treatment and care can lead to new side effects, but also environmental nano pollution. Little is known about the toxicology of these nanotechnology-based formulations, therefore, as future trends, more studies should be conducted to assure the consumers' health and environmental safety.

Cutibacterium acnes as an Opportunistic Pathogen: An Update of Its Virulence-Associated Factors

Cutibacterium acnes is a member of the skin microbiota found predominantly in regions rich in sebaceous glands. It is involved in maintaining healthy skin and has long been considered a commensal bacterium. Its involvement in various infections has led to its emergence as an opportunist pathogen. Interactions between C. acnes and the human host, including the human skin microbiota, promote the selection of C. acnes strains capable of producing several virulence factors that increase inflammatory capability. This pathogenic property may be related to many infectious mechanisms, such as an ability to form biofilms and the expression of putative virulence factors capable of triggering host immune responses or enabling C. acnes to adapt to its environment. During the past decade, many studies have identified and characterized several putative virulence factors potentially involved in the pathogenicity of this bacterium. These virulence factors are involved in bacterial attachment to target cells, polysaccharide-based biofilm synthesis, molecular structures mediating inflammation, and the enzymatic degradation of host tissues. C. acnes, like other skin-associated bacteria, can colonize various ecological niches other than skin. It produces several proteins or glycoproteins that could be considered to be active virulence factors, enabling the bacterium to adapt to the lipophilic environment of the pilosebaceous unit of the skin, but also to the various organs it colonizes. In this review, we summarize current knowledge concerning characterized C. acnes virulence factors and their possible implication in the pathogenicity of C. acnes.