Biao Ren

Sichuan University | SCU · State Key Laboratory of Oral Diseases

Objectives Gingivitis is the initial stage of periodontitis, one of the most common oral diseases and the primary cause of tooth loss. This study aims to evaluate the effect of toothpaste containing 2% zinc citrate on gingival health and the abundance of three bacteria related to gingivitis and periodontitis. Methods and Materials Eleven volunteer...

Four new polyketides, heterocornol Y (1), stemphyindan (2), pestalospirane C (3), and stemphyspyrane (4), along with five known ones (5–9) were isolated from the endophytic fungus Stemphylium globuliferum 17035 (SG17035) based on the One Strain Many Compounds (OSMAC) strategy allied with an LC-MS approach. These structures were elucidated through e...

Background The unbalanced oral microbiome is considered the key pathogenic agent for root caries, the most common tooth disease in elderly individuals; however, the bacteriome and mycobiome at different stages of root caries, especially from the same individual, are not clear. Results In this study, superficial and deep root caries plaques from th...

Background NETs, a unique neutrophil immune mechanism, are vital in defending against microbial invasions. Understanding the mechanisms of co-infection by Candida albicans and Staphylococcus aureus, which often leads to higher mortality and poorer prognosis, is crucial for studying infection progression. Methods In our study, we established a mous...

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 i...

Background: Emerging research demonstrates the regulatory effects of c-di-AMP, a bacterial-derived small molecule secondary messenger, on host immune responses and promoting resistance against infection-related diseases. This study aims to elucidate the role of c-di-AMP in the occurrence and development of periodontitis. Methods: We established lig...

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 e...

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....

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 m...

This study developed a novel pH-responsive monomer, DMAEM. It acts as a fungicide under acidic pH and suppresses filamentation under neutral pH, this dual mode of action provides therapeutic benefits in host environments with varying pH levels.

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 t...

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...

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, scannin...

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...

Background and Purpose: The holotoxin A1, isolated from Apostichopus japonicus, has shown potent antifungal activities with unclear mechanism and efficacy against candidiasis. This study aimed to reveal the antifungal effects and mechanism of holotoxin A1 against Candida albicans in vitro and in candidiasis murine models for the first time. Experim...

Background and Purpose: The holotoxin A1, isolated from Apostichopus japonicus, has shown potent antifungal activities with unclear mechanism and efficacy against candidiasis. This study aimed to reveal the antifungal effects and mechanism of holotoxin A1 against Candida albicans in vitro and in candidiasis murine models for the first time. Experim...

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 heav...

Nano-hydroxyapatite (nHAP) is considered a biocompatible agent that promotes the remineralization of dental hard tissue; however, its antibacterial efficacy is under scientific discussion. Therefore, this investigation aimed to specify the inhibitory effects of disaggregated nano-hydroxyapatite (DnHAP) on regrown biofilms and demineralization. Regr...

Oral candidiasis is the most common fungal infectious disease in human oral cavity and Candida albicans is the major pathogenic agent. The rising 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 C. albicans vi...

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...

Background: Candida albicans is the most common opportunistic fungal species in the oral cavity. The emergence of drug resistance of Candida albicans necessities the development of novel antifungal agents. Objectives: The current study evaluated the antifungal activity of a previously developed antimicrobial small molecule by our group, namely I...

The properties of titanium implants are affected by bio-aging due to long-term exposure to the oral microenvironment. This study aimed to investigate probable changes in titanium plates after different biofilm bio-aging processes, representing various oral status. Titanium plates with different surface treatments were used, including polish, sandbl...

Dental calculus has long been considered as a vital contributing factor of periodontal diseases. Our review focuses on the role of dental calculus as a repository and discusses the bioinformation recently reported to be concealed in dental calculus from three perspectives: time-varying oral condition, systemic diseases, and anthropology at various...

Untreated dental caries, tooth trauma and dental anatomical variations such as dens invaginatus can result in pulpitis. However, standard root canal therapy cannot treat immature permanent teeth due to an open apical foramen and thin dentinal walls. Thus, regenerative endodontics treatment (RET) following a disinfection step with pulp regeneration...

Oral bacteria directly affect the disease status of dental caries and periodontal diseases. The dynamic oral microbiota cooperates with the host to reflect the information and status of immunity and metabolism through two-way communication along the oral cavity and the systemic organs. The oral cavity is one of the most important interaction window...

Nasopharyngeal carcinoma (NPC) is a common head and neck cancer with a poor prognosis. There is an urgent need to develop a simple and convenient screening tool for early detection and risk screening of NPC. 139 microbial samples were collected from 40 healthy people and 39 patients with nasopharyngeal biopsy. A total of 40 and 39 oral, eight and 2...

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 1...

Candida albicans is a symbiotic fungus that commonly colonizes on oral mucosal surfaces and mainly affects immuno-compromised individuals. Polymicrobial interactions between C. albicans and oral microbes influence the cellular and biochemical composition of the biofilm, contributing to change clinically relevant outcomes of biofilm-related oral dis...

Persistent apical periodontitis is a critical challenge for endodontists. Developing root canal filling materials with continuous antibacterial effects and tightly sealed root canals are essential strategies to avoid the failure of root canal therapy and prevent persistent apical periodontitis. We modified the EndoREZ root canal sealer with the ant...

(1) Background: Enterococcus faecalis and Candida albicans are often isolated from infected root canals. The interaction between these two species is not clear enough. Therefore, the objective of this study was to investigate the effect of E. faecalis on the biofilm formation, hyphal morphogenesis and virulence gene expression of C. albicans. (2) M...

The cross-kingdom interactions between Candida albicans and Streptococcus mutans have played important roles in early childhood caries (ECC). However, the key pathways of C. albicans promoting the cariogenicity of S. mutans are still unclear. Here, we found that C. albicans CHK1 gene was highly upregulated in their dual-species biofilms. C. albican...

Background: Secondary caries often result in a high failure rate of resin composite restoration. Herein, we studied the dodecylmethylaminoethyl methacrylate-modified resin adhesive (DMAEM@RA) to investigate its pH-responsive antimicrobial effect on Streptococcus mutans and Candida albicans dual-species biofilms and on secondary caries. Methods:...

In the human body, each microbial habitat exhibits a different microbial population pattern, and these distinctive microflorae are highly related to the development of diseases. The microbial interactions from host different niches are becoming crucial regulators to shape the microbiota and their physiological or pathological functions. The oral ca...

Oral cavity is an ideal habitat for more than 1,000 species of microorganisms. The diverse oral microbes form biofilms over the hard and soft tissues in the oral cavity, affecting the oral ecological balance and the development of oral diseases, such as caries, apical periodontitis, and periodontitis. Currently, antibiotics are the primary agents a...

Background Oral squamous cell carcinoma (OSCC) is the most common tumor in the oral cavity. Methicillin-resistant Staphylococcus aureus (MRSA) were highly detected in OSCC patients; however, the interactions and mechanisms between drug-resistant bacteria (MRSA) and OSCC are not clear. Aim The aim of this study was to investigate the promotion of M...

The cross-kingdom interactions between Candida albicans and Actinomyces viscosus play critical roles in root caries. However, the key pathway by which C. albicans regulates its interactions with A. viscosus is unclear. Here, we first employed 39 volunteers with root caries and 37 caries-free volunteers, and found that the abundances of C. albicans...

Cross-kingdom interactions between Candida albicans and oral streptococci such as Streptococcus gordonii have been reported. However, their interactions in a low-fermentable-carbohydrate environment like saliva is not clear.

Fungal infection threatens human health worldwide due to the limited arsenal of antifungals and the rapid emergence of resistance. Epidermal growth factor receptor (EGFR) is demonstrated to mediate epithelial cell endocytosis of the leading human fungal pathogen, Candida albicans. However, whether EGFR inhibitors act on fungal cells remains unknown...

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been raging across the world for over two years, but the daily reported numbers of new infections and deaths are still increasing. The newly identified Omicron variant has significant changes in its transmissibility and pa...

Objective: To study the effects of CD47-targted immunotherapy on the oral-gut microbiota of immune-competent mice. Methods: A peritoneal metastatic colon cancer model was constructed in immune-competent mice. Anti-CD47 monoclonal antibody was intraperitoneally administered to the mice in the treatment group, while PBS was administered to mice in...

Malaria, caused by Plasmodium, is a global life-threatening infectious disease. However, the dynamic interactions between intestinal microbiota and host immunity during the infections are still unclear. Here, we investigated the change of intestinal microbiome and transcriptome during Plasmodium yoelii infection in mice. The mice were infected with...

The phenotypic traits of Streptococcus mutans , such as fluoride tolerance, are usually associated with genotypic alterations. The aim of this study was to identify adaptive mutations of S. mutans to gradient fluoride concentrations and possible relationships between the mutations and fluoride tolerance. We identified a highly resistant S. mutans s...

Background: COVID-19 is a novel coronavirus infectious disease associated with the severe acute respiratory syndrome. More and more patients are being cured due to the development of clinical guidelines for COVID-19 pneumonia diagnosis, treatment, and vaccines. However, the long-term impact of COVID-19 on patients after recovery is unclear. Current...

Genome editing technology has progressed rapidly in recent years. Although traditional gene-editing methods, including homologous recombination, zinc finger endonucleases, and transcription activator-like effector nucleases, have substantial implications for research in genetics and molecular biology, but they have remarkable limitations, including...

Peri-implantitis are a major problem causing implant failure these days. Accordingly, anti-infection during the early stage and subsequent promotion of osseointegration are two main key factors to solve this issue. Micro-arc oxidation (MAO) treatment is a way to form an oxidation film on the surface of metallic materials. The method shows good oste...

Background The shift of oral microbiota is a critical factor of radiation caries in head and neck cancer patients after the radiotherapy. However, the direct effects of irradiation on the genome and virulence of cariogenic bacteria are poorly described. Here we investigated the genomic mutations and virulence change of Streptococcus mutans ( S. mut...

Oral Microbiology is a vital component of the basic science of stomatology and an important compulsory course for undergraduate students of stomatology, focusing on the oral microbiology and microecology, the pathogenesis of oral infectious diseases, and the relationship between oral microbes and human health. Our faculty team have made reforms of...

A biologically active microbial strain, designated as LS462, was isolated from a soil sample collected from Yaoli Virgin Forest of Jiangxi Province, China. The strain was able to produce a high yield of echinomycin (172 mg/L) even under non-optimized culture conditions and proposed to serve as a promising source of echinomycin. In this study, echin...

Aims: COVID-19 pandemic caused by SARS-CoV-2 has become a public health crisis worldwide. In this study we aimed at demonstrating the neutralizing potential of the IgY produced after immunizing chicken with a recombinant SARS-CoV-2 spike protein S1 subunit. Methods and results: E. coli BL21 carrying plasmid pET28a-S1 was induced with IPTG for th...

Smoking is considered a key risk factor for implant survival; however, how it interacts with the pathogens in peri-implant infections is not clear. Here, we identified that nicotine, the key component of cigarette smoking, can interact with Staphylococcus aureus and synergistically induce peri-implant infections in a rat osteolysis model. The nicot...

Cancer is a significant global health problem and is characterized by a consistent increase in incidence and mortality rate. Deciphering the etiology and risk factors are essential parts of cancer research. Recently, the altered microbiome has been identified within the tumor microenvironment, tumor tissue, and even nonadjacent environments, which...

Introduction The oral squamous cell carcinoma (OSCC) is detrimental to patients’ physical and mental health. The prognosis of OSCC depends on the early diagnosis of OSCC in large populations. Objectives Here, the present study aimed to develop an early diagnostic model based on the relationship between OSCC and oral microbiota. Methods Overall, 1...

The mixed species of Staphylococcus aureus and Candida albicans can cause infections on skin, mucosa or bloodstream; however, mechanisms of their cross-kingdom interactions related to pathogenesis and drug resistance are still not clear. Here an increase of S. aureus proliferation and biofilm formation was observed in S. aureus and C. albicans dual...

Objectives Pit and fissure sealant is used in the prevention of dental caries. However, commercial pit and fissure sealant lacks persistent antibacterial properties. Dimethylaminododecyl methacrylate (DMADDM) was added to pit and fissure sealants to give it sustainable antibacterial properties and anti-microbial aging properties. Methods Resin-bas...

Objectives Microleakage is a determinant factor of failures in sealant application. In this study, DMAEM (dodecylmethylaminoethyl methacrylate), a pH-responsive antibacterial agent, was incorporated into resin-based sealant for the first time. The objectives of this study were to: (1) investigate the long-term performance of DMAEM-modified sealants...

Candida albicans, which can cause superficial and life-threatening systemic infections, is the most common opportunistic fungal pathogen in the human microbiome. The two-component system is one of the most important C. albicans signal transduction pathways, regulating the response to oxidative and osmotic stresses, adhesion, morphogenesis, cell wal...

Fungal terpenoids catalyzed by bifunctional terpene synthases (BFTSs) possess interesting bioactive and chemical properties. In this study, an integrated approach of genome mining, heterologous expression, and in vitro enzymatic activity assay was used, and these identified a unique BFTS sub-clade critical to the formation of a 5-15 trans-fused bic...

Genome editing technology develop fast in recent years. The traditional gene-editing methods, including homologous recombination, zinc finger endonuclease, and transcription activator-like effector nuclease and so on, which have greatly promoted the research of genetics and molecular biology, have gradually showed their limitations such as low effi...

Mucosa protects the body against external pathogen invasion. However, pathogen colonies on the mucosa can invade the mucosa when the immunosurveillance is compromised, causing mucosal infection and subsequent diseases. Therefore, it is necessary to timely and effectively monitor and control pathogenic microorganisms through mucosal immunity. Candid...

The infection of Enterococcus faecalis and its interacting microorganisms in the root canal could cause persistent apical periodontitis (AP). Antibacterial root canal sealer has favorable prospects to inhibit biofilms. The purpose of this study was to investigated the antibacterial effect of root canal sealer containing dimethylaminododecyl methacr...

Marine microbes provide an important resource to discover new chemical compounds with biological activities beneficial to drug discovery. In our study, two new polyene macrolides, pyranpolyenolides A (1) and B (2), and one new natural cyclic peptide (9), together with two known polyenes (7 and 8) and three known cyclic peptides (10–12), were isolat...

Oral candidiasis, especially caused by Candida albicans, is the most common fungal infection in the oral cavity. The increase of drug resistance and lack of new antifungal agents call for new strategies of fungal treatment. This study repurposed artemisinin (Art) as a potentiator to amphotericin B (AmB) and characterized their synergistic mechanism...