CD47-SIRPα Blockade Sensitizes Head and Neck Squamous Cell Carcinoma to Cetuximab by Enhancing Macrophage Adhesion to Cancer Cells.

Developing effective treatments for patients with head and neck squamous cell carcinoma (HNSCC) is a significant challenge. Cetuximab, a first-line targeted therapy for HNSCC, exhibits limited efficacy. Here, we used pooled CRISPR screening to find targets that can synergize with cetuximab and identified CD47 as the leading candidate. Rather than inhibiting cancer cell proliferation, CD47 inhibition promoted cetuximab-triggered antibody-dependent cellular phagocytosis (ADCP), thereby enhancing macrophage-mediated cancer cell removal. The combination of CD47-SIRPα blockade and cetuximab demonstrated strong anticancer activity in vivo. In addition to blocking the phagocytosis checkpoint, CD47-SIRPα inhibition upregulated CD11b/CD18 on the surface of macrophages, which accelerated intercellular adhesion between macrophages and cancer cells to enhance subsequent phagocytosis. Inhibition of the interaction between macrophage CD11b/CD18 and cancer cell ICAM1 eliminated the intercellular adhesion and phagocytosis induced by CD47-SIRPα blockade. Thus, CD47-SIRPα blockade enhances ADCP through CD11b/CD18-ICAM1-mediated intercellular adhesion and sensitizes HNSCC to cetuximab.

Candida species in periodontitis: A new villain or a new target?

OBJECTIVES: Recent research indicated that fungi might have a role in periodontitis alongside traditional periodontal pathogens. This state-of-the-art narrative review explores current concepts on the involvement of Candida species in periodontitis, and suggests the potential for ecological management of this disease. DATA, SOURCES AND STUDY SELECTION: A literature search was conducted for a narrative review on Web of Science, PubMed, Medline and Scopus about periodontitis associated with Candida species. Published articles, including case reports, case series, observational and interventional clinical trials, and critical appraisals of the literature were retrieved and reviewed. CONCLUSIONS: Several factors predispose individuals to periodontitis associated with Candida species. These include systemic diseases that lead to immunosuppression and oral environment changes such as cigarette smoking. While a consistent significant increase in the detection rate of Candida species in patients with periodontitis has not been universally observed, there is evidence linking Candida species to the severity of periodontitis and their potential to worsen the condition. Candida species may participate in the development of periodontitis in various ways, including cross-kingdom interactions with periodontal pathogens, changes in the local or systemic environment favoring the virulence of Candida species, and interactions between Candida-bacteria and host immunity. CLINICAL SIGNIFICANCE: Mechanical plaque control is the most common treatment for periodontitis, but its effectiveness may be limited, particularly when dealing with systemic risk factors. Understanding the specific role of Candida in periodontitis illuminates innovative approaches for managing the ecological balance in periodontal health.

Incorporation of PD-1 blockade into induction chemotherapy improved tumor response in patients with locoregionally advanced nasopharyngeal carcinoma in a retrospective patient cohort.

OBJECTIVE: To investigate the short-term efficacy and safety of induction chemotherapy (IC) combined with anti-PD-1 immunotherapy in locoregionally advanced nasopharyngeal carcinoma (LA-NPC). METHODS: A total of 217 patients diagnosed with LA-NPC at the First Affiliated Hospital of Nanchang University, including 67 who received IC combined with anti-PD-1 and 150 who received IC, were retrospectively enrolled. Efficacy was evaluated at the end of the IC cycles and one month after radiotherapy based on RECIST v1.1 criteria. Acute toxicities were graded based on the CTCAE v5.0 criteria. Quantitative variables were compared by unpaired t-tests, and categorical variables were evaluated by Fisher Freeman-Halton test or Pearson Chi-square test. RESULTS: At the end of all induction therapy cycles, the objective response rate (ORR) of the IC + anti-PD-1 group was 88.1 % (59/67) as opposed to 70.0 % (105/150) in the IC group. Subgroup analysis showed that patients in both stage Ⅲ and ⅣA achieved a significant improvement in ORR with the inclusion of anti-PD-1 therapy. Patients with T3-4 or N2-3 category appeared to benefit more from anti-PD-1 compared to patients with T1-2 or N0-1 category. However, neither ORR nor the complete response (CR) rate was significantly different between the two treatment groups one month after the end of radiotherapy. In addition, the frequency of Grade 3-4 adverse events were also similar in both groups. CONCLUSIONS: IC combined with anti-PD-1 immunotherapy significantly improved the ORR of LA-NPC patients after induction therapy compared to IC alone.

Secretory IgA reduced the ergosterol contents of Candida albicans to repress its hyphal growth and virulence.

Candida albicans, one of the most prevalent conditional pathogenic fungi, can cause local superficial infections and lethal systemic infections, especially in the immunocompromised population. Secretory immunoglobulin A (sIgA) is an important immune protein regulating the pathogenicity of C. albicans. However, the actions and mechanisms that sIgA exerts directly against C. albicans are still unclear. Here, we investigated that sIgA directs against C. albicans hyphal growth and virulence to oral epithelial cells. Our results indicated that sIgA significantly inhibited C. albicans hyphal growth, adhesion, and damage to oral epithelial cells compared with IgG. According to the transcriptome and RT-PCR analysis, sIgA significantly affected the ergosterol biosynthesis pathway. Furthermore, sIgA significantly reduced the ergosterol levels, while the addition of exogenous ergosterol restored C. albicans hyphal growth and adhesion to oral epithelial cells, indicating that sIgA suppressed the growth of hyphae and the pathogenicity of C. albicans by reducing its ergosterol levels. By employing the key genes mutants (erg11Δ/Δ, erg3Δ/Δ, and erg3Δ/Δ erg11Δ/Δ) from the ergosterol pathway, sIgA lost the hyphal inhibition on these mutants, while sIgA also reduced the inhibitory effects of erg11Δ/Δ and erg3Δ/Δ and lost the inhibition of erg3Δ/Δ erg11Δ/Δ on the adhesion to oral epithelial cells, further proving the hyphal repression of sIgA through the ergosterol pathway. We demonstrated for the first time that sIgA inhibited C. albicans hyphal development and virulence by affecting ergosterol biosynthesis and suggest that ergosterol is a crucial regulator of C. albicans-host cell interactions. KEY POINTS: • sIgA repressed C. albicans hyphal growth • sIgA inhibited C. albicans virulence to host cells • sIgA affected C. albicans hyphae and virulence by reducing its ergosterol levels.

Holotoxin A1 from Apostichopus japonicus inhibited oropharyngeal and intra-abdominal candidiasis by inducing oxidative damage in Candida albicans.

BACKGROUND AND PURPOSE: The holotoxin A1, isolated from Apostichopus japonicus, exhibits potent antifungal activities, but the mechanism and efficacy against candidiasis are unclear. In this study we have studied the antifungal effects and mechanism of holotoxin A1 against Candida albicans and in murine oropharyngeal and intra-abdominal candidiasis. EXPERIMENTAL APPROACH: The antifungal effect of holotoxin A1 against C. albicans was tested in vitro. To explore the antifungal mechanism of holotoxin A1, the transcriptome, ROS levels, and mitochondrial function of C. albicans was evaluated. Effectiveness and systematic toxicity of holotoxin A1 in vivo was assessed in the oropharyngeal and intra-abdominal candidiasis models in mice. KEY RESULTS: Holotoxin A1 was a potent fungicide against C. albicans SC5314, clinical strains and drug-resistant strains. Holotoxin A1 inhibited oxidative phosphorylation and induced oxidative damage by increasing intracellular accumulation of ROS in C. albicans. Holotoxin A1 induced dysfunction of mitochondria by depolarizing the mitochondrial membrane potential and reducing the production of ATP. Holotoxin A1 directly inhibited the enzymatic activity of mitochondrial complex I and antagonized with the rotenone, an inhibitor of complex I, against C. albicans. Meanwhile, the complex I subunit NDH51 null mutants showed a decreased susceptibility to holotoxin A1. Furthermore, holotoxin A1 significantly reduced fungal burden and infections with no significant systemic toxicity in oropharyngeal and intra-abdominal candidiasis in murine models. CONCLUSION AND IMPLICATIONS: Holotoxin A1 is a promising candidate for the development of novel antifungal agents against both oropharyngeal and intra-abdominal candidiasis, especially when caused by drug-resistant strains.

Omics for deciphering oral microecology.

The human oral microbiome harbors one of the most diverse microbial communities in the human body, playing critical roles in oral and systemic health. Recent technological innovations are propelling the characterization and manipulation of oral microbiota. High-throughput sequencing enables comprehensive taxonomic and functional profiling of oral microbiomes. New long-read platforms improve genome assembly from complex samples. Single-cell genomics provides insights into uncultured taxa. Advanced imaging modalities including fluorescence, mass spectrometry, and Raman spectroscopy have enabled the visualization of the spatial organization and interactions of oral microbes with increasing resolution. Fluorescence techniques link phylogenetic identity with localization. Mass spectrometry imaging reveals metabolic niches and activities while Raman spectroscopy generates rapid biomolecular fingerprints for classification. Culturomics facilitates the isolation and cultivation of novel fastidious oral taxa using high-throughput approaches. Ongoing integration of these technologies holds the promise of transforming our understanding of oral microbiome assembly, gene expression, metabolites, microenvironments, virulence mechanisms, and microbe-host interfaces in the context of health and disease. However, significant knowledge gaps persist regarding community origins, developmental trajectories, homeostasis versus dysbiosis triggers, functional biomarkers, and strategies to deliberately reshape the oral microbiome for therapeutic benefit. The convergence of sequencing, imaging, cultureomics, synthetic systems, and biomimetic models will provide unprecedented insights into the oral microbiome and offer opportunities to predict, prevent, diagnose, and treat associated oral diseases.

Development of Antibacterial Peptides with Membrane Disruption and Folate Pathway Inhibitory Activities against Methicillin-Resistant Staphylococcus aureus.

Antimicrobial peptides (AMPs) offer an opportunity to overcome multidrug resistance. Here, novel peptides were designed based on AMP fragments derived from sea cucumber hemolytic lectin to enhance anti-methicillin-resistant Staphylococcus aureus (MRSA) activity with less side effects. Two designed peptides, CGS19 (LARVARRVIRFIRRAW-NH2) and CGS20 (RRRLARRLIFFIRRAW-NH2), exhibited strong antibacterial activities against clinically isolated MRSA with MICs of 3-6 µM, but no obvious cytotoxicity was observed. Consistently, CGS19 and CGS20 exerted rapid bactericidal activity and effectively induced 5.9 and 5.8 log reduction of MRSA counts in mouse subeschar, respectively. Further, CGS19 and CGS20 kill bacteria not only through disturbing membrane integrity but also by binding formate-tetrahydrofolate ligase, a key enzyme in the folate metabolism pathway, thereby inhibiting the folate pathway of MRSA. CGS19 and CGS20 are promising lead candidates for drug development against MRSA infection. The dual mechanisms on the identical peptide sequence or scaffold might be an underappreciated manner of treating life-threatening pathogens.

Simultaneously characterization of multiple constituents in Valeriana jatamansi Jones using an online supercritical fluid extraction-high-performance liquid chromatography/supercritical fluid chromatography-mass spectrometry system.

Valeriana jatamansi Jones is a commonly used traditional Chinese medicine, boasting rich effective compositions with versatile chemical structures and wide polarity, including iridoids, chlorogenic acid, and flavonoids. Previous reports indicate that conventional high-performance liquid chromatography (HPLC) analytical methods have proven inefficient performance in comprehensively characterizing components in Valeriana jatamansi. In the present study, a hybrid online analytical platform combining supercritical fluid extraction with both conventional HPLC separation (reverse phase) and supercritical fluid chromatography (normal phase) has been established and validated. This system can provide online extraction with two different chromatographic separation modes to increase separation ability and has been connected to a mass spectrometer to acquire high-resolution mass spectrometry data. Then, the online platform was applied to screening components in Valeriana jatamansi. A total of 117 compounds were identified, including five lignans, 18 organic acids, six flavonoids, and 88 iridoids. Thirty-three compounds were reported from Valeriana jatamansi for the first time. These results enrich our understanding of the components of Valeriana jatamansi and prove that the developed online platform in this study is a robust approach for accelerating working efficiency in comprehensively analyzing complicated samples.

Stimulus-responsive biomaterials for Helicobacter pylori eradication.

BACKGROUND: Helicobacter pylori (H. pylori), the only bacterium classified as a type I (definite) carcinogen, is strongly associated with the development of gastric inflammation and adenocarcinoma. It infects the stomach of approximately half of the global population, equivalent to nearly 4.4 billion people. However, due to physiological barriers in the stomach, microbial barriers and increased antibiotic resistance, the therapeutic efficiency of standard antibiotic therapy is limited and cannot meet the clinical needs in some areas. Combining stimulus-responsive biomaterials with certain stimuli is an emerging antibacterial strategy. Stimulus-responsive biomaterials can respond to chemical, biological or physical cues in the environment with corresponding changes in their own properties and functions, highlighting a more intelligent, targeting and efficient aspect for H. pylori therapy. AIM OF REVIEW: This review describes the critical obstacles in the current treatment of H. pylori, summarizes the recent advances in stimulus-responsive biomaterials against H. pylori by elucidating their working mechanisms and antibacterial performances under different types of stimuli (pH, enzymes, light, magnetic and ultrasound irradiations), and attempts to analyze the future prospects of such smart biomaterial for H. pylori eradication. Key Scientific Concepts of Review: Any characteristic property or change in the biomilieu at the H. pylori infected site (endogenous stimuli) or specific iatrogenic conditions in vitro (exogenous stimuli) can act as cues to activate or potentiate the antibacterial activity of responsive biomaterials. The responsiveness of these materials to endogenous stimuli enhances antimicrobial targeting, and makes physiological barriers that would otherwise hinder conventional H. pylori therapies a key factor in facilitating antibacterial effects. The responsiveness to exogenous stimuli greatly prolongs the action time of antimicrobial materials and pinpoints the site of infection, thereby reducing toxic side effects. These findings pave the way for the development of more precise and effective anti-H. pylori treatment.

Lysine lactylation regulates metabolic pathways and biofilm formation in Streptococcus mutans.

In eukaryotes, lactate produced during glycolysis is involved in regulating multiple metabolic processes through lysine lactylation (Kla). To explore the potential link between metabolism and Kla in prokaryotes, we investigated the distribution of Kla in the cariogenic bacterium Streptococcus mutans during planktonic growth in low-sugar conditions and in biofilm-promoting, high-sugar conditions. We identified 1869 Kla sites in 469 proteins under these two conditions, with the biofilm growth state showing a greater number of lactylated sites and proteins. Although high sugar increased Kla globally, it reduced lactylation of RNA polymerase subunit α (RpoA) at Lys173. Lactylation at this residue inhibited the synthesis of extracellular polysaccharides, a major constituent of the cariogenic biofilm. The Gcn5-related N-acetyltransferase (GNAT) superfamily enzyme GNAT13 exhibited lysine lactyltransferase activity in cells and lactylated Lys173 in RpoA in vitro. Either GNAT13 overexpression or lactylation of Lys173 in RpoA inhibited biofilm formation. These results provide an overview of the distribution and potential functions of Kla and improve our understanding of the role of lactate in the metabolic regulation of prokaryotes.

Artemisinins inhibit oral candidiasis caused by Candida albicans through the repression on its hyphal development.

Candida albicans is the most abundant fungal species in oral cavity. As a smart opportunistic pathogen, it increases the virulence by switching its forms from yeasts to hyphae and becomes the major pathogenic agent for oral candidiasis. However, the overuse of current clinical antifungals and lack of new types of drugs highlight the challenges in the antifungal treatments because of the drug resistance and side effects. Anti-virulence strategy is proved as a practical way to develop new types of anti-infective drugs. Here, seven artemisinins, including artemisinin, dihydroartemisinin, artemisinic acid, dihydroartemisinic acid, artesunate, artemether and arteether, were employed to target at the hyphal development, the most important virulence factor of C. albicans. Artemisinins failed to affect the growth, but significantly inhibited the hyphal development of C. albicans, including the clinical azole resistant isolates, and reduced their damage to oral epithelial cells, while arteether showed the strongest activities. The transcriptome suggested that arteether could affect the energy metabolism of C. albicans. Seven artemisinins were then proved to significantly inhibit the productions of ATP and cAMP, while reduced the hyphal inhibition on RAS1 overexpression strain indicating that artemisinins regulated the Ras1-cAMP-Efg1 pathway to inhibit the hyphal development. Importantly, arteether significantly inhibited the fungal burden and infections with no systemic toxicity in the murine oropharyngeal candidiasis models in vivo caused by both fluconazole sensitive and resistant strains. Our results for the first time indicated that artemisinins can be potential antifungal compounds against C. albicans infections by targeting at its hyphal development.

Dimethylaminododecyl Methacrylate-Incorporated Dental Materials Could Be the First Line of Defense against Helicobacter pylori.

Oral cavity is an essential reservoir for H. pylori. We aimed to investigate the antibacterial effects of dimethylaminododecyl methacrylate (DMADDM) against H. pylori. Modified giomers were prepared by introducing 0%, 1.25% and 2.5% DMADDM monomers. Broth microdilution assay, spot assay, Alamer Blue assay, PMA-qPCR, crystal violet staining, scanning electron microscopy observation and live/dead bacterial staining were performed to evaluate the antibacterial and antibiofilm effects of DMADDM and modified giomers in vitro. Urease assay, qPCR, hematoxylin-eosin staining and ELISA were performed to evaluate the inflammation levels and colonization of H. pylori in vivo. In vitro experiments indicated that the minimum inhibitory concentration and minimum bactericidal concentration of DMADDM were 6.25 µg/mL and 25 µg/mL, respectively. It inhibited H. pylori in a dose- and time-dependent manner, and significantly reduced the expression of cagA, vacA, flaA and ureB. DMADDM-modified giomers inhibited the formation of H. pylori biofilm and reduced live cells within it. In vivo experiments confirmed that the pretreatment with DMADDM-modified dental resin effectively reduced the gastric colonization of oral-derived H. pylori, suppressed systemic and local gastric inflammation. DMADDM monomers and DMADDM-modified giomers possessed excellent antibacterial and antibiofilm effects on H. pylori. Pretreatment with DMADDM-modified giomers significantly inhibited the gastric infection by H. pylori.

Akkermansia muciniphila inhibited the periodontitis caused by Fusobacterium nucleatum.

Periodontitis is the most important cause of tooth loss in adults and is closely related to various systemic diseases. Its etiologic factor is plaque biofilm, and the primary treatment modality is plaque control. Studies have confirmed that Fusobacterium nucleatum can cause periodontitis through its virulence factors and copolymerizing effects with other periodontal pathogens, such as the red complex. Inhibiting F. nucleatum is an essential target for preventing periodontitis. The time-consuming and costly traditional periodontal treatment, periodontal scaling, and root planing are a significant burden on individual and public health. Antibiotic use may lead to oral microbial resistance and microbiome imbalance, while probiotics regulate microbial balance. Akkermansia muciniphila is a critical probiotic isolated from the human intestine. It can protect the integrity of the epithelial barrier, regulate and maintain flora homeostasis, improve metabolism, and colonize the oral cavity. Its abundance is inversely correlated with various diseases. We hypothesized that A. muciniphila could inhibit the effects of F. nucleatum and alleviate periodontitis. Bacterial co-culture experiments showed that A. muciniphila could inhibit the expression of the virulence gene of F. nucleatum. After treating gingival epithelial cells (GECs) with F. nucleatum and A. muciniphila, transcriptome sequencing and ELISA experiments on medium supernatant showed that A. muciniphila inhibited the inflammatory effect of F. nucleatum on GECs by inhibiting TLR/MyD88/NF-κB pathway modulation and secretion of inflammatory factors. Finally, animal experiments demonstrated that A. muciniphila could inhibit F. nucleatum-induced periodontitis in BALB/c mice.

Heavy Ion Radiation Directly Induced the Shift of Oral Microbiota and Increased the Cariogenicity of Streptococcus mutans.

Radiation caries is one of the most common complications of head and neck radiotherapy. A shift in the oral microbiota is the main factor of radiation caries. A new form of biosafe radiation, heavy ion radiation, is increasingly being applied in clinical treatment due to its superior depth-dose distribution and biological effects. However, how heavy ion radiation directly impacts the oral microbiota and the progress of radiation caries are unknown. Here, unstimulated saliva samples from both healthy and caries volunteers and caries-related bacteria were directly exposed to therapeutic doses of heavy ion radiation to determine the effects of radiation on oral microbiota composition and bacterial cariogenicity. Heavy ion radiation significantly decreased the richness and diversity of oral microbiota from both healthy and caries volunteers, and a higher percentage of Streptococcus was detected in radiation groups. In addition, heavy ion radiation significantly enhanced the cariogenicity of saliva-derived biofilms, including the ratios of the genus Streptococcus and biofilm formation. In the Streptococcus mutans-Streptococcus sanguinis dual-species biofilms, heavy ion radiation increased the ratio of S. mutans. Next, S. mutans was directly exposed to heavy ions, and the radiation significantly upregulated the gtfC and gtfD cariogenic virulence genes to enhance the biofilm formation and exopolysaccharides synthesis of S. mutans. Our study demonstrated, for the first time, that direct exposure to heavy ion radiation can disrupt the oral microbial diversity and balance of dual-species biofilms by increasing the virulence of S. mutans, increasing its cariogenicity, indicating a potential correlation between heavy ions and radiation caries. IMPORTANCE The oral microbiome is crucial to understanding the pathogenesis of radiation caries. Although heavy ion radiation has been used to treat head and neck cancers in some proton therapy centers, its correlation with dental caries, especially its direct effects on the oral microbiome and cariogenic pathogens, has not been reported previously. Here, we showed that the heavy ion radiation directly shifted the oral microbiota from a balanced state to a caries-associated state by increasing the cariogenic virulence of S. mutans. Our study highlighted the direct effect of heavy ion radiation on oral microbiota and the cariogenicity of oral microbes for the first time.

Streptococcus mutans sigX-inducing peptide inhibits the virulence of Candida albicans and oral candidiasis through the Ras1-cAMP-Efg1 pathway.

Oral candidiasis is the most common fungal infectious disease in the human oral cavity, and Candida albicans is the major pathogenic agent. Increasing drug resistance and the lack of new types of antifungals greatly increase the challenges for treating fungal infections. Targeting hyphal transition provides a promising strategy to inhibit the virulence of C. albicans and overcome drug resistance. This study aimed to investigate the effects and mechanisms of sigX-inducing peptide (XIP), a quorum-sensing signal peptide secreted by Streptococcus mutans, on C. albicans hyphal development and biofilm formation in vitro and oropharyngeal candidiasis in vivo. XIP significantly inhibited C. albicans yeast-to-hypha transition and biofilm formation in a dose-dependent manner from 0.01 to 0.1 µM. XIP significantly downregulated expression of genes from the Ras1-cAMP-Efg1 pathway (RAS1, CYR1, TPK2, EFG1 and UME6), a key pathway to regulate C. albicans hyphal development. Importantly, XIP reduced the levels of key molecules cAMP and ATP from this pathway, while the addition of exogenous cAMP and overexpression of RAS1 restored the hyphal development inhibited by XIP. XIP also lost its hyphal inhibitory effects on ras1Δ/Δ and efg1Δ/Δ strains. These results further confirmed that XIP inhibited hyphal development through downregulation of the Ras1-cAMP-Efg1 pathway. A murine oropharyngeal candidiasis model was employed to evaluate the therapeutic effects of XIP on oral candidiasis. XIP effectively reduced the infected epithelial area, fungal burden, hyphal invasion and inflammatory infiltrates. These results revealed the antifungal effects of XIP, and highlighted that XIP can be a potential antifungal peptide against C. albicans infection.

pH-responsive DMAEM Monomer for dental caries inhibition.

Previous research indicated that there is an aggregate of microorganism in oral cavity which takes part in promoting the occurrence of dental caries, but few studies on anticaries materials for these 'core microbiome' were developed. And We've found that DMAEM monomer has an obvious inhibitory effect on the growth of Streptococcus mutans and saliva biofilm, but the effect of that on the "core microbiome" of caries need further research. Thus, the objectives of this study were to explore the effect of DMAEM monomer on the core microbiota of dental caries, and to further study its anticaries effect. The changes of microbial structure and metabolic activity of the core microbiota biofilm were detected through measuring lactic acid yield, viable bacteria counts and demineralization depth, et al., and the anticaries potential in vivo of DMAEM monomer was evaluated by rat caries model. Meanwhile, high-throughput sequencing was used to analyze the microbial diversity change of saliva samples of rats. The results showed that DMAEM monomer could inhibit the growth of the core microbiota biofilm, decrease the metabolic activity and the acid production, as well as reduce the ability of demineralization under acidic conditions. Moreover, the degree of caries in the DMAEM group was significantly reduced, and the diversity and the evenness of oral microecology in the rats were statistically higher. In summary, DMAEM monomer could respond to acidic environment, significantly inhibit the cariogenic ability of the 'core microbiome' of caries, and help to maintain the microecological balance of oral cavity.

Small molecule II-6s synergises with fluconazole against Candida albicans.

BACKGROUND: Candida albicans (C. albicans) is the most common opportunistic fungal species in the oral cavity. The emergence of drug resistance of C. albicans has necessitated the development of novel antifungal agents. OBJECTIVES: This study evaluated the antifungal activity of a previously developed antimicrobial small molecule, namely II-6s, and explored its potential synergism with fluconazole against C. albicans and the underlying mechanisms. METHODS: The antifungal effects of II-6s against C. albicans were evaluated with microdilution and time-killing assays. Synergism of II-6s with fluconazole was determined by calculating the fractional inhibitory concentration index (FICI). The effects of II-6s on efflux pump, mitochondrial function and energy metabolism were examined to investigate the underlying mechanism of synergism. The antifungal mechanism of II-6s against C. albicans was further explored with RNA-seq and validated with specific mutant strains. RESULTS: II-6s exhibited a fungicidal effect against C. albicans with a minimum fungicidal concentration of 31.25 µg/mL. II-6s also inhibited C. albicans biofilm with a sessile minimum inhibitory concentration at 500 µg/mL. More importantly, II-6s showed a synergistic effect with fluconazole against a fluconazole-resistant strain of C. albicans, which expressed elevated levels of CDR1 (FICI < 0.5). II-6s inhibited the efflux pump activity of C. albicans. Consistently, II-6s inhibited energy metabolism of C. albicans by reducing the mitochondrial membrane potential and ATP generation, and inhibited utilisation of the non-fermentable carbon source. II-6s also inhibited the mitogen-activated protein kinase signal pathway, particularly HOG1, which may explain its antifungal activity against C. albicans. CONCLUSION: The small molecule II-6s inhibits the growth of C. albicans by targeting HOG1. II-6s also synergises with fluconazole by inhibiting the drug efflux pump, representing a promising antifungal agent for the control of candidiasis.

Extracellular vesicles of Candida albicans regulate its own growth through the L-arginine/nitric oxide pathway.

Candida albicans is the main conditional pathogenic fungus among the human microbiome. Extracellular vesicles (EVs) secreted by C. albicans are important for its pathogenesis. However, the effects and mechanisms of EVs on C. albicans own growth are not clear. Here, we isolated EVs from C. albicans cells grown in four culture media, including RPMI 1640, DMEM, YPD, and YNB, and measured their effects on the own growth of C. albicans in these media. All the C. albicans EVs from the four media could promote the growth of C. albicans in RPMI 1640 and DMEM media, but had no effects in YPD and YNB media, indicating that the effects of EVs on C. albicans growth were dependent on some media contents. By comparing the media contents and transcriptome analysis, arginine was identified as the key factor for the growth promotion of C. albicans EVs. EVs activated the L-arginine/nitric oxide pathway to promote the growth of C. albicans through that EVs increased the NO levels and upregulated the expression of NO dioxygenase gene YHB1 to reduce the intracellular reactive oxygen species (ROS) and cell apoptosis. During the host cell infections, C. albicans EVs synergistically enhanced the destructive effects of C. albicans to host cells, including RAW264.7, HOK, TR146, and HGEC, suggesting that the growth promotion by EVs enhanced the pathogenesis of C. albicans. Our results demonstrated the important roles of EVs on C. albicans own growth for the first time and highlight its synergism with C. albicans to increase the pathogenesis. KEY POINTS: • C. albicans extracellular vesicles (EVs) promoted its own growth. • EVs activated the l-arginine/NO pathway to reduce ROS and apoptosis of C. albicans. • EVs enhanced the damage to the host cell caused by C. albicans.

Research progress on the relationship between periodontal pathogens and colorectal cancer / 口腔疾病防治

@#With the deepening of the research on the relationship between oral microbiota and systemic diseases, researchers have found that periodontitis is closely related to diabetes, cardiovascular disease, digestive system disease and other systemic diseases. Fusobacterium nucleatum (Fn) and Porphyromonas gingivalis (Pg) are common periodontal pathogens, which play a key role in the occurrence and development of periodontitis. At present, it is also found that Fn and Pg are closely related to the occurrence and development of colorectal cancer (CRC). They can affect the occurrence and development of CRC and the therapeutic effect and prognosis of CRC patients through a variety of ways. It can promote tumor cell proliferation by regulating cell division cycle and inhibiting cell apoptosis, inhibit immune cell function to mediate immune escape and tumor metastasis, and create a pro-inflammatory microenvironment suitable for tumor survival. The study of the effect of periodontal pathogens on the occurrence and development of colorectal cancer and its mechanism also allows us to think about new methods, such as vaccine development, immune agents and antibiotic use to better prevent and treat colorectal cancer and improve the prognosis of patients with colorectal cancer.

Inducible co-stimulatory molecules participate in mesenteric vascular endothelial-mesenchymal transition and sclerosis of mesenteric vessels in spontaneously hypertensive rats / 南方医科大学学报

OBJECTIVE@#To investigate the correlation of inducible co-stimulatory molecules (ICOS) with mesenteric vascular endothelial- mesenchymal transition (EndMT) and sclerosis in spontaneously hypertensive rats (SHR).@*METHODS@#Twenty 4-week-old WKY rats and 20 SHRs of the same strain were both randomly divided into 4 groups for observation at 4, 6, 10 and 30 weeks of age. ICOS expression frequency in rat spleen CD4+T cells was analyzed using flow cytometry, and the expressions of ICOS, VE-cad, α-SMA and Col3 mRNA in rat mesentery were detected by RT-PCR. The distributions of ICOS, IL-17A and TGF-β in rat mesentery were detected by immunohistochemistry. The levels of IL-17A and TGF-β in rat plasma were measured using ELISA. The morphological changes of rat mesenteric vessels were observed with Masson staining. Spearman or Pearson correlation analyses were used to evaluate the correlation between ICOS expression and the expressions of the markers of vascular EndMT and sclerosis.@*RESULTS@#Compared with the control WKY rats, the SHRs began to show significantly increased systolic blood pressure and ICOS expression frequency on CD4+T cells at 6 weeks of age (P < 0.05). In the SHRs, the mRNA and protein expressions of ICOS, α-SMA, Col3, IL-17A and TGF-β in the mesentery were significantly higher than those in control group (P < 0.05), while the mRNA and protein expressions of VE-cad started to reduce significantly at 10 weeks of age (P < 0.05). The plasma levels of IL-17A and TGF-β were significantly increased in SHRs since 6 weeks of age (P < 0.05) with progressive worsening of mesenteric vascular sclerosis (P < 0.05). ICOS mRNA and protein expression levels in the mesenteric tissues of SHRs began to show positive correlations with α-SMA and Col3 expression levels and the severity of vascular sclerosis at 6 weeks of age (P < 0.05) and a negative correlation with VE-cad expression level at 10 weeks (P < 0.05).@*CONCLUSION@#ICOS play an important pathogenic role in EndMT and sclerosis of mesenteric vessels in essential hypertension by mediating related immune responses.