Microbiota association and profiling o 1 fgingival sulci and root canals of teeth with primary or secondary/persistent endodontic infections.

INTRODUCTION: Microbiota associated with primary (PEI) and secondary/persistent (SPEI) endodontic infections must be characterized to elucidate pathogenesis in apical periodontitis and bacterial biomarkers identified for diagnostic and therapeutic applications. METHODS: This study analyzed the microbial community profiles of root canals and gingival sulci (sulcus-E) for teeth with PEI (n = 10) or SPEI (n = 10), using the Illumina MiSeq platform. Bacterial samples from gingival sulci (sulcus-C) of healthy contralateral teeth served as controls. RESULTS: There were 15 phyla, 177 genera, and 340 species identified. The number and diversity of bacteria in root canals did not differ significantly between PEI and SPEI. Proteobacteria, Firmicutes, Fusobacteria, Bacteroidetes, and Actinobacteria were the dominant phyla in both groups. At the genus level, Lancefieldella, Bifidobacterium, Stomatobaculum, and Schaalia were enriched in root canals with SPEI. Of significance, Lancefieldella was observed in both root canals and sulcus-E of teeth with SPEI. At the species level, Neisseria macacae, Streptococcus gordonii, Bifidobacterium dentium, Stomatobaculum longum, and Schaalia odontolytica were increased significantly in root canals with SPEI compared to PEI. Oribacterium species, Streptococcus salivarius, Lancefieldella parvula, Prevotella denticola, and Oribacterium asaccharolyticum were more abundant in sulcus-E of teeth with SPEI compared to PEI. CONCLUSIONS: There were distinctive and differing predominant bacterial species associated with the root canals and gingival sulci between teeth with PEI and SPEI. Specific bacteria identified in sulcus-E and root canals of teeth with SPEI could serve as non-invasive diagnostic biomarkers for detecting SPEI.

Photosynthetic responses of Larix kaempferi and Pinus densiflora seedlings are affected by summer extreme heat rather than by extreme precipitation.

The frequency and intensity of summer extreme climate events are increasing over time, and have a substantial negative effect on plants, which may be evident in their impact on photosynthesis. Here, we examined the photosynthetic responses of Larix kaempferi and Pinus densiflora seedlings to extreme heat (+ 3 °C and + 6 °C), drought, and heavy rainfall by conducting an open-field multifactor experiment. Leaf gas exchange in L. kaempferi showed a decreasing trend under increasing temperature, showing a reduction in the stomatal conductance, transpiration rate, and net photosynthetic rate by 135.2%, 102.3%, and 24.8%, respectively, in the + 6 °C treatment compared to those in the control. In contrast, P. densiflora exhibited a peak function in the stomatal conductance and transpiration rate under + 3 °C treatment. Furthermore, both species exhibited increased total chlorophyll contents under extreme heat conditions. However, extreme precipitation had no marked effect on photosynthetic activities, given the overall favorable water availability for plants. These results indicate that while extreme heat generally reduces photosynthesis by triggering stomatal closure under high vapor pressure deficit, plants employ diverse stomatal strategies in response to increasing temperature, which vary among species. Our findings contribute to the understanding of mechanisms underlying the photosynthetic responses of conifer seedlings to summer extreme climate events.

Bacillus subtilis Induces Human Beta Defensin-2 Through its Lipoproteins in Human Intestinal Epithelial Cells.

Human intestinal epithelial cells (IECs) play an important role in maintaining gut homeostasis by producing antimicrobial peptides (AMPs). Bacillus subtilis, a commensal bacterium, is considered a probiotic. Although its protective effects on intestinal health are widely reported, the key component of B. subtilis responsible for its beneficial effects remains elusive. In this study, we tried to identify the key molecules responsible for B. subtilis-induced AMPs and their molecular mechanisms in a human IEC line, Caco-2. B. subtilis increased human beta defensin (HBD)-2 mRNA expression in a dose- and time-dependent manner. Among the B. subtilis microbe-associated molecular patterns, lipoprotein (LPP) substantially increased the mRNA expression and protein production of HBD-2, whereas lipoteichoic acid and peptidoglycan did not show such effects. Those results were confirmed in primary human IECs. In addition, both LPP recognition and HBD-2 secretion mainly took place on the apical side of fully differentiated and polarized Caco-2 cells through Toll-like receptor 2-mediated JNK/p38 MAP kinase/AP-1 and NF-κB pathways. HBD-2 efficiently inhibited the growth of the intestinal pathogens Staphylococcus aureus and Bacillus cereus. Furthermore, LPPs pre-incubated with lipase or proteinase K decreased LPP-induced HBD-2 expression, suggesting that the lipid and protein moieties of LPP are crucial for HBD-2 expression. Q Exactive Plus mass spectrometry identified 35 B. subtilis LPP candidates within the LPP preparation, and most of them were ABC transporters. Taken together, these results suggest that B. subtilis promotes HBD-2 secretion in human IECs mainly with its LPPs, which might enhance the protection from intestinal pathogens.

Serotype-Dependent Inhibition of Streptococcus pneumoniae Growth by Short-Chain Fatty Acids.

Streptococcus pneumoniae (pneumococcus) is an opportunistic pathogen that can cause severe infectious diseases such as pneumonia, meningitis, and otitis media. Despite the availability of antibiotics and pneumococcal vaccines against some invasive serotypes, pneumococcal infection remains a tremendous clinical challenge due to the increasing frequency of infection by antimicrobial resistant, nonencapsulated, and/or non-vaccine serotype strains. Short-chain fatty acids (SCFAs), which are produced at various mucosal sites in the body, have potent antimicrobial activity, including inhibition of pathogen growth and/or bacterial biofilm formation. In this study, we investigated the antimicrobial activity of SCFAs (acetate, propionate, and butyrate) against various serotypes pneumococci. Propionate generally inhibited the growth of S. pneumoniae serotypes included in the pneumococcal conjugate vaccine (PCV) 13, except for serotypes 3 and 7F, though butyrate and acetate showed no or low inhibition, depending on the serotypes. Of note, butyrate showed strong inhibition against serotype 3, the most prevalent invasive strain since the introduction of the PCV. No SCFAs showed inhibitory effects against serotype 7F. Remarkably, the nonencapsulated pneumococcal strain had more sensitivity to SCFAs than encapsulated parental strains. Taken together, these results suggest that propionate showing the most potent inhibition of pneumococcal growth may be used as an alternative treatment for pneumococcal infection, and that butyrate could be used against serotype 3, which is becoming a serious threat.

Antimicrobial activity, surface properties, and cytotoxicity of microencapsulated phytochemicals incorporated into three-dimensionally printable dental polymers.

OBJECTIVES: This study aimed to investigate the antimicrobial properties of three dimensionally-printed dental polymers (3DPs) incorporated with microencapsulated phytochemicals (MPs) and to assess their surface characteristics and cytotoxicity. METHODS: MPs derived from phytoncide oil and their specific chemical components were introduced into suspensions of three microbial species: Streptococcus gordonii, Streptococcus oralis, and Candida albicans. Optical density was measured to determine the microbial growth in the presence of MPs for testing their antimicrobial activity. MPs at 5% (w/w) were mixed with dental polymers and dispersants to 3DP discs. These microbial species were then seeded onto the discs and incubated for 24 h. The antibacterial and antifungal activities of MP-containing 3DPs were evaluated by counting the colony-forming units (n = 3). The biofilm formation on the 3DP was assessed by crystal violet staining assay (n = 3). Microbial viability was determined using a live-dead staining and CLSM observation (n = 3). Surface roughness and water contact angle were assessed (n = 10). Cytotoxicity of MP-containing 3DPs for human gingival fibroblast was evaluated by MTT assay. RESULTS: MPs, particularly (-)-α-pinene, suppressed the growth of all tested microbial species. MP-containing 3DPs significantly reduced the colony count (P ≤ 0.001) and biofilm formation (P ≤ 0.009), of all tested microbial species. Both surface roughness (P < 0.001) and water contact angle (P < 0.001) increased. The cytotoxicity remained unchanged after incorporating MPs to the 3DPs (P = 0.310). CONCLUSIONS: MPs effectively controlled the microbial growth on 3DPs as evidenced by the colony count, biofilm formation, and cell viability. Although MPs modified the surface characteristics, they did not influence the cytotoxicity of 3DPs. CLINICAL SIGNIFICANCE: Integration of MPs into 3DPs could produce dental prostheses or appliances with antimicrobial properties. This approach not only provides a proactive solution to reduce the risk of oral biofilm-related infection but also ensures the safety and biocompatibility of the material, thereby improving dental care.

Lipoproteins are key immunostimulatory components of Bacillus species for dendritic cell maturation and activation.

Dendritic cells (DCs) play an important role in immunity by sensing and responding to invasive microbes. Bacillus species are rod-shaped sporulating bacteria that include the pathogenic Bacillus cereus and commensal Bacillus subtilis. Although the interaction between DC and these two Bacillus species has been studied, their key structural component that prompts DC activation is poorly understood. Here, we investigated the two Bacillus species in DC activation by whole cells and their representative microbe-associated molecular patterns (MAMPs). MAMPs including lipoteichoic acid (LTA), lipoprotein (LPP), and peptidoglycan (PGN) were purified from the two Bacillus species. Among the MAMPs, LPP from both species most potently induced the maturation and activation of DCs while PGN, but not LTA, moderately stimulated DCs. LPPs from both Bacillus species enhanced the expression of DC maturation markers including CCR7, CD40, CD80, CD83, CD86, CD205, MHC-I, and MHC-II. Among the MAMPs from B. cereus, PGN most considerably lowered the endocytic capacity of DCs implying DC maturation whereas PGN from B. subtilis lowered it to a similar degree to its LPP. Furthermore, DCs sensitized with LPPs from both Bacillus species and PGN from B. subtilis moderately induced TNF-α and IL-6 production. Notably, a combination of MAMPs did not show any synergistic effect on DC activation. Taken together, our results demonstrate that LPP is the key structural component in B. cereus and B. subtilis that leads to DC activation.

Pinostilbene inhibits full-length and splice variant of androgen receptor in prostate cancer.

Prostate cancer is the most prevalent cancer in men worldwide and is promoted by the sex hormone androgen. Expression of androgen from the testis can be significantly reduced through castration. However, as most prostate cancer patients acquire castration resistance, additional therapeutic solutions are necessary. Although anti-androgens, such as enzalutamide, have been used to treat castration-resistant prostate cancer (CRPC), enzalutamide-resistant CRPC (Enz-resistant CRPC) has emerged. Therefore, development of novel treatments for Enz-resistant CRPC is urgent. In this study, we found a novel anti-androgen called pinostilbene through screening with a GAL4-transactivation assay. We confirmed that pinostilbene directly binds to androgen receptor (AR) and inhibits its activation and translocalization. Pinostilbene treatment also reduced the protein level and downstream gene expression of AR. Furthermore, pinostilbene reduced the protein level of AR variant 7 in the Enz-resistant prostate cancer cell line 22Rv1 and inhibited cell viability and proliferation. Our results suggest that pinostilbene has the potential to treat Enz-resistant CRPC.

Lipoteichoic acid inhibits osteoclast differentiation and bone resorption via interruption of gelsolin-actin dissociation.

Bone resorption can be caused by excessive differentiation and/or activation of bone-resorbing osteoclasts. While microbe-associated molecular patterns can influence the differentiation and activation of bone cells, little is known about the role of lipoteichoic acid (LTA), a major cell wall component of Gram-positive bacteria, in the regulation of bone metabolism. In this study, we investigated the effect of LTA on bone metabolism using wild-type Staphylococcus aureus and the LTA-deficient mutant strain. LTA-deficient S. aureus induced higher bone loss and osteoclast differentiation than wild-type S. aureus. LTA isolated from S. aureus (SaLTA) inhibited osteoclast differentiation from committed osteoclast precursors in the presence of various osteoclastogenic factors by downregulating the expression of NFATc1. Remarkably, SaLTA attenuated the osteoclast differentiation from committed osteoclast precursors of TLR2-/- or MyD88-/- mice and from the committed osteoclast precursors transfected with paired immunoglobulin-like receptor B-targeting siRNA. SaLTA directly interacted with gelsolin, interrupting the gelsolin-actin dissociation which is a critical process for osteoclastogenesis. Moreover, SaLTA suppressed the mRNA expression of dendritic cell-specific transmembrane protein, ATPase H+ transporting V0 subunit D2, and Integrin, which encode proteins involved in cell-cell fusion of osteoclasts. Notably, LTAs purified from probiotics, including Bacillus subtilis, Enterococcus faecalis, and Lactobacillus species, also suppressed Pam2CSK4- or RANKL-induced osteoclast differentiation. Taken together, these results suggest that LTAs have anti-resorptive activity through the inhibition of osteoclastogenesis by interfering with the gelsolin-actin dissociation and may be used as effective therapeutic agents for the prevention or treatment of inflammatory bone diseases.

The eGFR Decline as a Risk Factor for Metabolic Syndrome in the Korean General Population: A Longitudinal Study of Individuals with Normal or Mildly Reduced Kidney Function.

Metabolic syndrome (MS) is a risk factor for the development and progression of chronic kidney disease (CKD). However, it is unclear whether decreased renal function affects MS. Through a longitudinal study, we investigated the effect of estimated glomerular filtration rate (eGFR) changes on MS in participants with an eGFR above 60 mL/min/1.73 m2. A cross-sectional (n = 7107) and a 14-year longitudinal study (n = 3869) were conducted to evaluate the association between MS and eGFR changes from the Korean Genome and Epidemiology Study data. The participants were categorized by their eGFR levels (60-75, 75-90, and 90-105 versus ≥ 105 mL/min/1.73 m2). In a cross-sectional analysis, the MS prevalence was significantly increased with a decline in the eGFR in a fully adjusted model. The odds ratio of individuals with an eGFR of 60-75 mL/min/1.73 m2 was observed to be the highest (2.894; 95% confidence interval (CI), 1.984-4.223). In the longitudinal analysis, incident MS significantly increased with an eGFR decline in all the models, with the highest hazard ratio in the lowest eGFR group (1.803; 95% CI, 1.286-2.526). In joint interaction analysis, all covariates showed a significant joint effect with an eGFR decline on the incident MS. MS incidents are associated with eGFR changes in the general population without CKD.

SH3YL1 Protein Predicts Renal Outcomes in Patients with Type 2 Diabetes.

NADPH oxidase (NOX)-derived oxidative stress is an important factor in renal progression, with NOX4 being the predominant NOX in the kidney. Recently, Src homology 3 (SH3) domain-containing YSC84-like 1 (SH3YL1) was reported to be a regulator of NOX4. In this study, we tested whether the SH3YL1 protein could predict 3-year renal outcomes in patients with type 2 diabetes. A total of 131 patients with type 2 diabetes were enrolled in this study. Renal events were defined as a 15% decline in the estimated glomerular filtration rate (eGFR) from the baseline, the initiation of renal replacement therapy, or death during the 3 years. The levels of the urinary SH3YL1-to-creatinine ratio (USCR) were significantly different among the five stages of chronic kidney disease (CKD) and the three groups, based on albuminuria levels. The USCR levels showed a significant negative correlation with eGFR and a positive correlation with the urinary albumin-to-creatinine ratio (UACR). Plasma SH3YL1 levels were significantly correlated with UACR. The highest tertile group of USCR and plasma SH3YL1 had a significantly lower probability of renal event-free survival. Furthermore, the highest tertile group of USCR showed a significant association with the incidence of renal events after full adjustment: adjusted hazard ratio (4.636: 95% confidence interval, 1.416-15.181, p = 0.011). This study suggests that SH3YL1 is a new diagnostic biomarker for renal outcomes in patients with type 2 diabetes.

Lipoteichoic acid of Streptococcus gordonii as a negative regulator of human dendritic cell activation.

Streptococcus gordonii, an opportunistic Gram-positive bacterium, causes an infective endocarditis that could be fatal to human health. Dendritic cells (DCs) are known to be involved in disease progression and immune responses in S. gordonii infection. Since lipoteichoic acid (LTA) is a representative virulence factor of S. gordonii, we here investigated its role in the activation of human DCs stimulated with LTA-deficient (ΔltaS) S. gordonii or S. gordonii LTA. DCs were differentiated from human blood-derived monocytes in the presence of GM-CSF and IL-4 for 6 days. DCs treated with heat-killed ΔltaS S. gordonii (ΔltaS HKSG) showed relatively higher binding and phagocytic activities than those treated with heat-killed wild-type S. gordonii (wild-type HKSG). Furthermore, ΔltaS HKSG was superior to wild-type HKSG in inducing phenotypic maturation markers including CD80, CD83, CD86, PD-L1, and PD-L2, antigen-presenting molecule MHC class II, and proinflammatory cytokines such as TNF-α and IL-6. Concomitantly, DCs treated with the ΔltaS HKSG induced better T cell activities, including proliferation and activation marker (CD25) expression, than those treated with the wild-type. LTA, but not lipoproteins, isolated from S. gordonii weakly activated TLR2 and barely affected the expression of phenotypic maturation markers or cytokines in DCs. Collectively, these results demonstrated that LTA is not a major immuno-stimulating agent of S. gordonii but rather it interferes with bacteria-induced DC maturation, suggesting its potential role in immune evasion.

Estrogen Mediates the Sexual Dimorphism of GT1b-Induced Central Pain Sensitization.

We have previously reported that the intrathecal (i.t.) administration of GT1b, a ganglioside, induces spinal cord microglia activation and central pain sensitization as an endogenous agonist of Toll-like receptor 2 on microglia. In this study, we investigated the sexual dimorphism of GT1b-induced central pain sensitization and the underlying mechanisms. GT1b administration induced central pain sensitization only in male but not in female mice. Spinal tissue transcriptomic comparison between male and female mice after GT1b injection suggested the putative involvement of estrogen (E2)-mediated signaling in the sexual dimorphism of GT1b-induced pain sensitization. Upon ovariectomy-reducing systemic E2, female mice became susceptible to GT1b-induced central pain sensitization, which was completely reversed by systemic E2 supplementation. Meanwhile, orchiectomy of male mice did not affect pain sensitization. As an underlying mechanism, we present evidence that E2 inhibits GT1b-induced inflammasome activation and subsequent IL-1ß production. Our findings demonstrate that E2 is responsible for sexual dimorphism in GT1b-induced central pain sensitization.

Butyrate potentiates Enterococcus faecalis lipoteichoic acid-induced inflammasome activation via histone deacetylase inhibition.

Enterococcus faecalis, a Gram-positive opportunistic pathogen having lipoteichoic acid (LTA) as a major virulence factor, is closely associated with refractory apical periodontitis. Short-chain fatty acids (SCFAs) are found in the apical lesion and may affect inflammatory responses induced by E. faecalis. In the current study, we investigated inflammasome activation by E. faecalis LTA (Ef.LTA) and SCFAs in THP-1 cells. Among SCFAs, butyrate in combination with Ef.LTA markedly enhanced caspase-1 activation and IL-1ß secretion whereas these were not induced by Ef.LTA or butyrate alone. Notably, LTAs from Streptococcus gordonii, Staphylococcus aureus, and Bacillus subtilis also showed these effects. Activation of TLR2/GPCR, K+ efflux, and NF-κB were necessary for the IL-1ß secretion induced by Ef.LTA/butyrate. The inflammasome complex comprising NLRP3, ASC, and caspase-1 was activated by Ef.LTA/butyrate. In addition, caspase-4 inhibitor diminished IL-1ß cleavage and release, indicating that non-canonical activation of the inflammasome is also involved. Ef.LTA/butyrate induced Gasdermin D cleavage, but not the release of the pyroptosis marker, lactate dehydrogenase. This indicated that Ef.LTA/butyrate induces IL-1ß production without cell death. Trichostatin A, a histone deacetylase (HDAC) inhibitor, enhanced Ef.LTA/butyrate-induced IL-1ß production, indicating that HDAC is engaged in the inflammasome activation. Furthermore, Ef.LTA and butyrate synergistically induced the pulp necrosis that accompanies IL-1ß expression in the rat apical periodontitis model. Taken all these results together, Ef.LTA in the presence of butyrate is suggested to facilitate both canonical- and non-canonical inflammasome activation in macrophages via HDAC inhibition. This potentially contributes to dental inflammatory diseases such as apical periodontitis, particularly associated with Gram-positive bacterial infection.

Muramyl dipeptide alleviates estrogen deficiency-induced osteoporosis through canonical Wnt signaling.

Wnt signaling is a positive regulator of bone formation through the induction of osteoblast differentiation and down-regulation of osteoclast differentiation. We previously reported that muramyl dipeptide (MDP) increases bone volume by increasing osteoblast activity and attenuating osteoclast activity in receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoporotic model mice. In this study, we investigated whether MDP could alleviate post-menopausal osteoporosis through Wnt signaling regulation in an ovariectomy (OVX)-induced mouse osteoporosis model. MDP-administered OVX mice exhibited higher bone volume and bone mineral density than mice of the control group. MDP significantly increased P1NP in the serum of OVX mice, implying increased bone formation. The expression of pGSK3ß and ß-catenin in the distal femur of OVX mice was lower than that in the distal femur of sham-operated mice. Yet, the expression of pGSK3ß and ß-catenin was increased in MDP-administered OVX mice compared with OVX mice. In addition, MDP increased the expression and transcriptional activity of ß-catenin in osteoblasts. MDP inhibited the proteasomal degradation of ß-catenin via the down-regulation of its ubiquitination by GSK3ß inactivation. When osteoblasts were pretreated with Wnt signaling inhibitors, DKK1 or IWP-2, the induction of pAKT, pGSK3ß, and ß-catenin was not observed. In addition, nucleotide oligomerization domain-containing protein 2-deficient osteoblasts were not sensitive to MDP. MDP-administered OVX mice exhibited fewer tartrate-resistant acid phosphatase (TRAP)-positive cells than did OVX mice, attributed to a decrease in the RANKL/OPG ratio. In conclusion, MDP alleviates estrogen deficiency-induced osteoporosis through canonical Wnt signaling and could be an effective therapeutic for the treatment of post-menopausal bone loss. © 2023 The Pathological Society of Great Britain and Ireland.

A novel defined TLR3 agonist as an effective vaccine adjuvant.

Synthetic double-stranded RNA analogs recognized by Toll-like receptor 3 (TLR3) are an attractive adjuvant candidate for vaccines, especially against intracellular pathogens or tumors, because of their ability to enhance T cell and antibody responses. Although poly(I:C) is a representative dsRNA with potent adjuvanticity, its clinical application has been limited due to heterogeneous molecular size, inconsistent activity, poor stability, and toxicity. To overcome these limitations, we developed a novel dsRNA-based TLR3 agonist named NexaVant (NVT) by using PCR-coupled bidirectional in vitro transcription. Agarose gel electrophoresis and reverse phase-HPLC analysis demonstrated that NVT is a single 275-kDa homogeneous molecule. NVT appears to be stable since its appearance, concentration, and molecular size were unaffected under 6 months of accelerated storage conditions. Moreover, preclinical evaluation of toxicity under good laboratory practices showed that NVT is a safe substance without any signs of serious toxicity. NVT stimulated TLR3 and increased the expression of viral nucleic acid sensors TLR3, MDA-5, and RIG-1. When intramuscularly injected into C57BL/6 mice, ovalbumin (OVA) plus NVT highly increased the migration of dendritic cells (DCs), macrophages, and neutrophils into inguinal lymph node (iLN) compared with OVA alone. In addition, NVT substantially induced the phenotypic markers of DC maturation and activation including MHC-II, CD40, CD80, and CD86 together with IFN-ß production. Furthermore, NVT exhibited an appropriate adjuvanticity because it elevated OVA-specific IgG, in particular, higher levels of IgG2c (Th1-type) but lower IgG1 (Th2-type). Concomitantly, NVT increased the levels of Th1-type T cells such as IFN-γ+CD4+ and IFN-γ+CD8+ cells in response to OVA stimulation. Collectively, we suggest that NVT with appropriate safety and effectiveness is a novel and promising adjuvant for vaccines, especially those requiring T cell mediated immunity such as viral and cancer vaccines.

Regulation of BRCA1 stability through the tandem UBX domains of isoleucyl-tRNA synthetase 1.

Aminoacyl-tRNA synthetases (ARSs) have evolved to acquire various additional domains. These domains allow ARSs to communicate with other cellular proteins in order to promote non-translational functions. Vertebrate cytoplasmic isoleucyl-tRNA synthetases (IARS1s) have an uncharacterized unique domain, UNE-I. Here, we present the crystal structure of the chicken IARS1 UNE-I complexed with glutamyl-tRNA synthetase 1 (EARS1). UNE-I consists of tandem ubiquitin regulatory X (UBX) domains that interact with a distinct hairpin loop on EARS1 and protect its neighboring proteins in the multi-synthetase complex from degradation. Phosphomimetic mutation of the two serine residues in the hairpin loop releases IARS1 from the complex. IARS1 interacts with BRCA1 in the nucleus, regulates its stability by inhibiting ubiquitylation via the UBX domains, and controls DNA repair function.

Propionate Attenuates Growth of Oral Streptococci through Enhancing Methionine Biosynthesis.

Oral streptococci are considered as an opportunistic pathogen associated with initiation and progression of various oral diseases. However, since the currently-available treatments often accompany adverse effects, alternative strategy is demanded to control streptococci. In the current study, we investigated whether short-chain fatty acids (SCFAs), including sodium acetate (NaA), sodium propionate (NaP), and sodium butyrate (NaB), can inhibit the growth of oral streptococci. Among the tested SCFAs, NaP most potently inhibited the growth of laboratory and clinically isolated strains of Streptococcus gordonii under anaerobic culture conditions. However, the growth inhibitory effect of NaP on six different species of other oral streptococci was different depending on their culture conditions. Metabolic changes such as alteration of methionine biosynthesis can affect bacterial growth. Indeed, NaP enhanced intracellular methionine levels of oral streptococci as well as the mRNA expression level of methionine biosynthesis-related genes. Collectively, these results suggest that NaP has an inhibitory effect on the growth of oral streptococci, which might be due to alteration of methionine biosynthesis. Thus, NaP can be used an effective bacteriostatic agent for the prevention of oral infectious diseases caused by oral streptococci.

Anti-allergic function of the cell wall (DeinoWall) from Deinococcus radiodurans.

Deinococcus radiodurans is an extremophile, well known to be extremely resistant to external stresses due to its unique physiological system and structure of cellular components. Although the proportion of D. radiodurans has been reported to be negatively correlated with atopic dermatitis, the exact function of D. radiodurans in allergic diseases and its precise mechanisms have not been studied. In the present study, we hypothesize that D. radiodurans or its cellular constituents play a critical role in the skin to prevent allergic inflammatory responses by modulating immunity. Heat-killed D. radiodurans inhibited the production of Th2 cytokines, such as IL-4 and IL-5, induced by ovalbumin (OVA) stimulation in splenocytes from OVA-sensitized mice. Among the cellular constituents of D. radiodurans, such as cell wall (DeinoWall), cell membrane (DeinoMem), and exopolysaccharide (DeinoPol), only DeinoWall inhibited the production of Th2 cytokines and 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD), a Th2-predominant allergic disease in mice. Moreover, serum IgE levels and infiltration of mast cells into skin lesions, the markers of Th2 response induced by DNCB application, were significantly inhibited by treatment with DeinoWall. Remarkably, DeinoWall induced the maturation of bone marrow-derived dendritic cells (BMDCs) that promote Th1-biased immunity, which might balance Th1/Th2 and regulate allergic inflammatory responses. Collectively, these results suggest that DeinoWall acts as a major cellular constituent in the negative regulation of allergic inflammatory responses by D. radiodurans and might be a viable candidate for the treatment of allergic diseases.

Development of Live Attenuated Salmonella Typhimurium Vaccine Strain Using Radiation Mutation Enhancement Technology (R-MET).

Salmonella enterica is a leading cause of food-borne diseases in humans worldwide, resulting in severe morbidity and mortality. They are carried asymptomatically in the intestine or gallbladder of livestock, and are transmitted predominantly from animals to humans via the fecal-oral route. Thus, the best preventive strategy is to preemptively prevent transmission to humans by vaccinating livestock. Live attenuated vaccines have been mostly favored because they elicit both cellular and humoral immunity and provide long-term protective immunity. However, developing these vaccines is a laborious and time-consuming process. Therefore, most live attenuated vaccines have been mainly used for phenotypic screening using the auxotrophic replica plate method, and new types of vaccines have not been sufficiently explored. In this study, we used Radiation-Mutation Enhancement Technology (R-MET) to introduce a wide variety of mutations and attenuate the virulence of Salmonella spp. to develop live vaccine strains. The Salmonella Typhimurium, ST454 strain (ST WT) was irradiated with Cobalt60 gamma-irradiator at 1.5 kGy for 1 h to maximize the mutation rate, and attenuated daughter colonies were screened using in vitro macrophage replication capacity and in vivo mouse infection assays. Among 30 candidates, ATOMSal-L6, with 9,961-fold lower virulence than the parent strain (ST454) in the mouse LD50 model, was chosen. This vaccine candidate was mutated at 71 sites, and in particular, lost one bacteriophage. As a vaccine, ATOMSal-L6 induced a Salmonella-specific IgG response to provide effective protective immunity upon intramuscular vaccination of mice. Furthermore, when mice and sows were orally immunized with ATOMSal-L6, we found a strong protective immune response, including multifunctional cellular immunity. These results indicate that ATOMSal-L6 is the first live vaccine candidate to be developed using R-MET, to the best of our knowledge. R-MET can be used as a fast and effective live vaccine development technology that can be used to develop vaccine strains against emerging or serotype-shifting pathogens.

8-Methoxybutin inhibits α-MSH induced melanogenesis and proliferation of skin melanoma by suppression of the transactivation activity of microphthalmia-associated transcription factor.

Microphthalmia-associated transcription factor (MITF) is highly expressed in melanocytes and is the main regulator of melanogenesis and melanocyte cell fate. Although MITF is important for the differentiation and development of melanocytes, it is also considered an oncogene of skin melanoma. Based on these findings, MITF could be an attractive therapeutic target for skin cancer intervention. This study identified 8-methoxybutin as an inhibitor of MITF and investigated the underlying mechanism. 8-Methoxybutin inhibited α-MSH-induced melanogenesis in murine melanoma cells (B16F10) and skin melanoma proliferation by reducing melanogenic gene expression via blockade of the transactivation activity of MITF. In silico docking analysis and pull-down analysis suggested that 8-methoxybutin binds to the DNA-binding domain of MITF and further inhibits its binding to the E-box in the promoter of target genes, including tyrosinase. In addition, 8-methoxybutin suppressed growth of skin melanoma in a xenograft mouse model. These results indicate that 8-methoxybutin has potential as a therapeutic agent for hyperpigmentation disorder and skin cancer. SIGNIFICANCE STATEMENT: 8-Methoxybutin inhibits MITF transactivation activity resulting suppression of melanogenesis and skin melanoma growth.