Comparative whole genome analysis of face-derived Streptococcus infantis CX-4 unravels the functions related to skin barrier.

BACKGROUND: The skin microbiome is essential in guarding against harmful pathogens and responding to environmental changes by generating substances useful in the cosmetic and pharmaceutical industries. Among these microorganisms, Streptococcus is a bacterial species identified in various isolation sources. In 2021, a strain of Streptococcus infantis, CX-4, was identified from facial skin and found to be linked to skin structure and elasticity. As the skin-derived strain differs from other S. infantis strains, which are usually of oral origin, it emphasizes the significance of bacterial variation by the environment. OBJECTIVE: This study aims to explore the unique characteristics of the CX-4 compared to seven oral-derived Streptococcus strains based on the Whole-Genome Sequencing data, focusing on its potential role in skin health and its possible application in cosmetic strategies. METHODS: The genome of the CX-4 strain was constructed using PacBio Sequencing, with the assembly performed using the SMRT protocol. Comparative whole-genome analysis was then performed with seven closely related strains, utilizing web-based tools like PATRIC, OrthoVenn3, and EggNOG-mapper, for various analyses, including protein association analysis using STRING. RESULTS: Our analysis unveiled a substantial number of Clusters of Orthologous Groups in diverse functional categories in CX-4, among which sphingosine kinase (SphK) emerged as a unique product, exclusively present in the CX-4 strain. SphK is a critical enzyme in the sphingolipid metabolic pathway, generating sphingosine-1-phosphate. The study also brought potential associations with isoprene formation and retinoic acid synthesis, the latter being a metabolite of vitamin A, renowned for its crucial function in promoting skin cell growth, differentiation, and maintaining of skin barrier integrity. These findings collectively suggest the potential of the CX-4 strain in enhancing of skin barrier functionality. CONCLUSION: Our research underscores the potential of the skin-derived S. infantis CX-4 strain by revealing unique bacterial compounds and their potential roles on human skin.

Enhancement of anti-tumor activity in melanoma using arginine deiminase fused with 30Kc19α protein.

Arginine deiminase (ADI) is a microbial-derived enzyme which catalyzes the conversion of L-arginine into L-citrulline. ADI originating from Mycoplasma has been reported to present anti-tumor activity against arginine-auxotrophic tumors, including melanoma. Melanoma cells are sensitive to arginine depletion due to reduced expression of argininosuccinate synthase 1 (ASS1), a key enzyme for arginine biosynthesis. However, clinical applications of recombinant ADI for melanoma treatment present some limitations. Since recombinant ADI is not human-derived, it shows instability, proteolytic degradation, and antigenicity in human serum. In addition, there is a problem of drug resistance issue due to the intracellular expression of once-silenced ASS1. Moreover, recombinant ADI proteins are mainly expressed as inclusion body forms in Escherichia coli and require a time-consuming refolding process to turn them back into active form. Herein, we propose fusion of recombinant ADI from Mycoplasma hominis and 30Kc19α, a cell-penetrating protein which also increases stability and soluble expression of cargo proteins, to overcome these problems. We inserted matrix metalloproteinase-2 cleavable linker between ADI and 30Kc19α to increase enzyme activity in melanoma cells. Compared to ADI, ADI-LK-30Kc19α showed enhanced solubility, stability, and cell penetration. The fusion protein demonstrated selective cytotoxicity and reduced drug resistance in melanoma cells, thus would be a promising strategy for the improved efficacy in melanoma treatment. KEY POINTS: • Fusion of ADI with 30Kc19α enhances soluble expression and productivity of recombinant ADI in E. coli • 30Kc19α protects ADI from the proteolytic degradation by shielding effect, helping ADI to remain active • Intracellular delivery of ADI by 30Kc19α overcomes ADI resistance in melanoma cells by degrading intracellularly expressed arginine.

Asthma Severity and the Controller Prescription in Children at 12 Tertiary Hospitals.

PURPOSE: Guidelines need to be tailored to where they are applied. We aimed to describe the distinctive asthma severity profile and the pattern of controller prescription in Korean children. METHODS: Twelve pediatric allergists from tertiary medical centers reviewed medical records of all asthmatic children who visited their clinics between September 1 and November 30 of 2013. Controller prescriptions were re-classified into 4 categories, then the prevalence of each asthma severity category and the controller prescription patterns according to asthma severity assessed by a Western (Global Initiative for Asthma, GINA) and an Asia-Pacific (Japanese Pediatric GuideLine, JPGL) guideline were evaluated. RESULTS: A total of 840 cases were reviewed. Both GINA and JPGL revealed that 328 (39.0%) and 249 (29.6%) subjects had intermittent asthma whereas 24 (2.9%) and 21 (2.5%) subjects had severe persistent asthma, respectively. Although higher category controllers tended to be prescribed to those who had more severe asthma, there was much overlap in categories of prescribed controllers between groups with regard to asthma severities. Leukotriene receptor antagonists (LTRA) was the most frequently prescribed as a single controller (40%) or as an add-on medication (19%) in the group of asthmatic children <6 years. CONCLUSIONS: Korean children have distinctive patterns of asthma severity and management strategies with a lower prevalence of severe asthma and a preference toward LTRA rather than low dose inhaled corticosteroids (ICS) alone or add-on long-acting beta-agonist (LABA) in the group of <6 year-old asthmatics that has not been predicted in Western countries. Thus, strategies tailored to regional situations need to be developed and recommended.