Dong-Kwon Rhee

Conventional immunization methods such as intramuscular injections lack effective mucosal protection against pathogens that enter through the mucosal surfaces. Moreover, conventional therapy often leads to adverse events and compromised immunity, followed by complicated outcomes, leading to the need to switch to other options. Thus, a need to develop safe and effective treatment with long-term beneficial outcomes to reduce the risk of relapse is mandatory. Mucosal vaccines administered across mucosal surfaces, such as the respiratory or intestinal mucosa, to prompt robust localized and systemic immune responses to prevent the public from acquiring pathogenic diseases. Mucosal immunity contains a unique immune cell milieu that selectively identify pathogens and limits the transmission and progression of mucosal diseases, such as allergic dermatitis and inflammatory bowel disease (IBD). It also offers protection from localized infection at the site of entry, enables the clearance of pathogens on mucosal surfaces, and leads to the induction of long-term immunity with the ability to shape regulatory responses. Regulatory T (Treg) cells have been a promising strategy to suppress mucosal diseases. To find advances in mucosal treatment, we investigated the therapeutic effects of intranasal pep27 mutant immunization. Nasal immunization protects mucosal surfaces, but nasal antigen presentation appears to entail the need for an adjuvant to stimulate immunogenicity. Here, a novel method is developed to induce Tregs via intranasal immunization without an adjuvant to potentially overcome allergic diseases and gut and lung inflammation using lung–gut axis communication in animal models. The implementation of the pep27 mutant for these therapies should be preceded by studies on Treg resilience through clinical translational studies on dietary changes.

Mucosal vaccines can target specific mucosal surfaces, such as the respiratory, genital, or intestinal mucosa. Conventional systemic immunization, such as intramuscular injections, do not provide mucosal immunity, including IgA, nor do they prevent pathogens from entering the mucous membranes. Nasal immunization protects mucosal membranes, but nasal antigen presentation appears to entail adjuvant to stimulate immunogenicity. Current treatments for mucosal diseases such as inflammatory bowel disease (IBD) and allergic dermatitis only aimed to temporarily relieve symptoms. Moreover, these treatments not only have drug resistance or side effects, but the disease can recur, leading to switching to other treatments. Therefore, there is a need to develop safe and effective treatments that provide better long-term outcomes to reduce the risk of recurrence. Regulatory T (Treg) cells have been used to suppress inflammation. To find advances in mucosal treatment, we investigated the therapeutic effects of intranasal pep27 mutant immunization. Here, a new method of Treg induction through intranasal immunization without adjuvant has been developed to potentially overcome allergies and mucosal inflammation of the lung-gut axis in animal models. The implementation of the pep27 mutant for these therapies should be preceded by studies of Treg resilience through clinical translational studies of dietary changes.

Inflammatory bowel disease (IBD) is a highly prevalent gut inflammatory disorder. Complicated clinical outcomes prolong the use of conventional therapy and often lead to compromised immunity followed by adverse events and high relapse rates. Thus, a profound medical intervention is required. Previously, intranasal immunization of pneumococcal pep27 mutant (Δpep27) exhibited long-lasting protection against immune-related disorders. System biology analysis has predicted an inverse correlation between Δpep27 immunization and gastroenteritis. Recently, we established that Δpep27-elicited Tregs repressed Wnt5a expression and enhanced barrier integrity, suggesting the restoration of immunological tolerance. Therefore, we evaluated whether Δpep27 can alleviate IBD. Δpep27 dose-dependent response was analyzed in dextran sulfate sodium-induced mice using transcriptome analysis. Pro- and anti-inflammatory signatures were cross-correlated by quantitative PCR and western blot analyses. To address the hierarchy regulating the activity of caspase-14, an undefined marker in IBD, and regulatory T cells (Tregs), antibody-based neutralization studies were conducted. Fecal microbiome profiles were analyzed by 16S rRNA pyrosequencing. Δpep27 significantly attenuated dextran sulfate sodium-induced oxidative stress parameters, proinflammatory cytokines, caspase-14 expression level, and upregulated tight junction, anti-inflammatory genes IL-10 and TGF-β1 via upregulation of Tregs to restore healthy gut microbiota. Neutralization studies unveiled that ∆pep27 had a remedial effect via Treg upregulation. Caspase-14, being an important mediator in the pathogenesis of IBD, can be an alternate therapeutic target in IBD. ∆pep27-increased Tregs repressed caspase-14 expression and reversed gut microbial dysbiosis, aiding to re-establish immunological tolerance.

Jae Ik Yu, Ji-Hoon Kim, Ki-El Nam, Wonsik Lee, and Dong-Kwon Rhee. J. Microbiol. Biotechnol. 2022;32:709-17. https://doi.org/10.4014/jmb.2203.03006

Aims: Inflammatory bowel disease (IBD) is a highly prevalent gut inflammatory disorder. Complicated clinical outcomes prolong the use of conventional therapy and often lead to compromised immunity followed by adverse events and high relapse rates. Thus, a profound medical intervention is required. Previously, intranasal immunization of pneumococcal pep27 mutant (Δpep27) exhibited long-lasting protection against immune-related disorders. System biology analysis has predicted an inverse correlation between Δpep27 immunization and gastroenteritis. Therefore, we evaluated whether Δpep27 can alleviate IBD. Main methods: Δpep27 dose-dependent response was analyzed in dextran sulfate sodium-induced mice using transcriptome analysis. Pro- and anti-inflammatory signatures were cross-correlated by quantitative PCR and western blot analyses. To address the hierarchy regulating the activity of caspase-14, an undefined marker in IBD, and regulatory T cells (Tregs), antibody-based neutralization studies were conducted. Fecal microbiome profiles were analyzed by 16S rRNA pyrosequencing. Key findings: Δpep27 significantly attenuated dextran sulfate sodium-induced oxidative stress parameters, proinflammatory cytokines, caspase-14 expression level, and upregulated tight junction, anti-inflammatory genes IL-10 and TGF-β1 via upregulation of Tregs to restore healthy gut microbiota. Neutralization studies unveiled that ∆pep27 had a remedial effect via Treg upregulation. Significance: ∆pep27-increased Tregs repressed caspase-14 expression and reversed gut microbial dysbiosis aiding to re-establish immunological tolerance. Caspase-14, being important mediator in the pathogenesis of IBD, can be an alternate therapeutic target in IBD.

Sang-Sang Park, Sangho Lee, and Dong-Kwon Rhee. Mol. Cells 2021;44:179-85. https://doi.org/10.14348/molcells.2021.2235