The Role of DSPP in Dentine Formation and Hereditary Dentine Defects.

The dentine sialophosphoprotein (DSPP) gene is the only identified causative gene for dentinogenesis imperfecta type 2 (DGI-II), dentinogenesis imperfecta type 3 (DGI-III) and dentine dysplasia type 2 (DD-II). These three disorders may have similar molecular mechanisms involved in bridging the DSPP mutations and the resulting abnormal dentine mineralisation. The DSPP encoding proteins DSP (dentine sialoprotein) and DPP (dentine phosphoprotein) are positive regulators of dentine formation and perform a function during dentinogenesis. The present review focused on the recent findings and viewpoints regarding the relationship between DSPP and dentinogenesis as well as mineralisation from multiple perspectives, involving studies relating to spatial structure and tissue localisation of DSPP, DSP and DPP, the biochemical characteristics and biological function of these molecules, and the causative role of the proteins in phenotypes of the knockout mouse model and in hereditary dentine defects.

Podocalyxin promotes the formation of compact and chemoresistant cancer spheroids in high grade serous carcinoma.

High grade serous carcinoma (HGSC) metastasises primarily intraperitoneally via cancer spheroids. Podocalyxin (PODXL), an anti-adhesive transmembrane protein, has been reported to promote cancer survival against chemotherapy, however its role in HGSC chemoresistance is unclear. This study investigated whether PODXL plays a role in promoting chemoresistance of HGSC spheroids. We first showed that PODXL was expressed variably in HGSC patient tissues (n = 17) as well as in ovarian cancer cell lines (n = 28) that are more likely categorised as HGSC. We next demonstrated that PODXL-knockout (KO) cells proliferated more slowly, formed less compact spheroids and were more fragile than control cells. Furthermore, when treated with carboplatin and examined for post-treatment recovery, PODXL-KO spheroids showed significantly poorer cell viability, lower number of live cells, and less Ki-67 staining than controls. A similar trend was also observed in ascites-derived primary HGSC cells (n = 6)-spheroids expressing lower PODXL formed looser spheroids, were more vulnerable to fragmentation and more sensitive to carboplatin than spheroids with higher PODXL. Our studies thus suggests that PODXL plays an important role in promoting the formation of compact/hardy HGSC spheroids which are more resilient to chemotherapy drugs; these characteristics may contribute to the chemoresistant nature of HGSC.

Simple Binding and Dissociation of a Sialoglycoprotein Using Boronic Acid-Modified Functional Interfaces on Microparticles.

An overexpression of sialic acid is an indicator of metastatic cancer, and selective detection of sialic acid shows potential for cancer diagnosis. Boronic acid is a promising candidate for this purpose because of its ability to specifically bind to sialic acid under acidic conditions. Notably, the binding strength can be easily modulated by adjusting the pH, which allows for a simple dissociation of the bound sialic acid. In this study, we developed 5-boronopicolinic acid (5-BPA)-modified magnetic particles (BMPs) to selectively capture sialic acid biomolecules. We successfully captured fetuin, a well-known sialoglycoprotein, on BMPs at >104 molecules/particle using an acetate buffer (pH 5.0). Facile dissociation then occurred when the system was changed to a pH 7.6 phosphate buffer. This capture-and-release process could be repeated at least five times. Moreover, this system could enrich fetuin by more than 20 times. In summary, BMPs are functional particles for facile purification and concentration through the selective capture of sialic acid proteins and can improve detection sensitivity compared with conventional methods. This technology shows potential for the detection of sialic acid overexpression by biological particles.

Isomeric Separation of α2,3/α2,6-Linked 2-Aminobenzamide (2AB)-Labeled Sialoglycopeptides by C18-LC-MS/MS.

Determination of the relative expression levels of the α2,3/α2,6-sialic acid linkage isomers on glycoproteins is critical to the analysis of various human diseases such as cancer, inflammation, and viral infection. However, it remains a challenge to separate and differentiate site-specific linkage isomers at the glycopeptide level. Some derivatization methods on the carboxyl group of sialic acid have been developed to generate mass differences between linkage isomers. In this study, we utilized chemical derivatization that occurred on the vicinal diol of sialic acid to separate linkage isomers on a reverse-phase column using a relatively short time. 2-Aminobenzamide (2AB) labeling derivatization, including periodate oxidation and reductive amination, took only ∼3 h and achieved high labeling efficiency (>90%). Within a 66 min gradient, the sialic acid linkage isomers of 2AB-labeled glycopeptides from model glycoproteins can be efficiently resolved compared to native glycopeptides. Two different methods, neuraminidase digestion and higher-energy collision dissociation tandem mass spectrometry (HCD-MS2) fragmentation, were utilized to differentiate those isomeric peaks. By calculating the diagnostic oxonium ion ratio of Gal2ABNeuAc and 2ABNeuAc fragments, significant differences in chromatographic retention times and in mass spectral peak abundances were observed between linkage isomers. Their corresponding MS2 PCA plots also helped to elucidate the linkage information. This method was successfully applied to human blood serum. A total of 514 2AB-labeled glycopeptide structures, including 152 sets of isomers, were identified, proving the applicability of this method in linkage-specific structural characterization and relative quantification of sialic acid isomers.

[Recognition on dentin dysplasia type â ¡].

Dentin dysplasia type Ⅱ (DD-Ⅱ) is a subtype of hereditary dentin disorders. The dentin sialophosphoprotein (DSPP) gene has been revealed to be the causative gene, whose mutations could affect the normal tooth development process. The lesions involve both deciduous and permanent dentition, mainly manifested as tooth discoloration, attrition and even the subsequent malocclusion. If not treated in time, it will significantly affect the physical and psychological health of patients. The disease is difficult to be diagnosed in clinic accurately as its low incidence and hidden manifestations. The present article aims to discuss the clinical and radiographic characteristics, diagnosis, treatment of DD-Ⅱ, in order to improve the overall understanding on DD-Ⅱ for clinicians.

A novel strategy for quantification of α2,3- and α2,6-linked sialic acids in sialylated glycoproteins.

Sialic acid, a monosaccharide containing nine carbon atoms, is widely distributed in eukaryotic cells. The bound sialic acids are mainly present at the glycan ends of glycoconjugates via α2-3 or α2-6 glycosidic bonds, and alterations in their expression levels and linkage types are associated with the progress of many diseases and tumors. The present study provides a new strategy for quantification of α2,3- and α2,6-linked sialic acids in sialylated glycoproteins. In fact, quantification of α2,3-linked sialic acids were based on the difference of the bound sialic acids in the sample before and after treatment with α2-3 neuraminidase, whereas the α2,6-linked sialic acids were equal to the bound sialic acids in the α2-3 neuraminidase-treated sample. Subsequently, α2,3/6-linked sialic acids in salivary glycoproteins from healthy volunteers and diabetic patients were quantified in accordance with this method. This work provides an accurate method for the quantification of α2,3- and α2,6-linked sialic acids in the sialoglycoproteins, which is more instructive for understanding the biological roles of α2,3/6-linked sialic acid in sialoglycoproteins.

AAV6-Mediated Gene Therapy Prevents Developmental Dentin Defects in a Dentinogenesis Imperfecta Type â ¢ Mouse Model.

Dentin is a major type of hard tissue of teeth and plays essential roles for normal tooth function. Odontoblasts are responsible for dentin formation. Mutations or deficiency in various genes affect the differentiation of odontoblasts, leading to irreversible dentin developmental defects in animals and humans. Whether such dentin defects can be reversed by gene therapy for odontoblasts remains unknown. In this study, we compare the infection efficiencies of six commonly used adeno-associated virus (AAV) serotypes (AAV1, AAV5, AAV6, AAV8, AAV9, and AAVDJ) in cultured mouse odontoblast-like cells (OLCs). We show that AAV6 serotype infects OLCs with the highest efficiency among the six AAVs. Two cellular receptors, which are able to recognize AAV6, AAV receptor (AAVR), and epidermal growth factor receptor (EGFR), are strongly expressed in the odontoblast layer of mouse teeth. After local administration to mouse molars, AAV6 infects the odontoblast layer with high efficiency. Furthermore, AAV6-Mdm2 was successfully delivered to teeth and prevents the defects in odontoblast differentiation and dentin formation in Mdm2 conditional knockout mice (a mouse model of dentinogenesis imperfecta type Ⅲ). These results suggest that AAV6 can serve as a reliable and efficient vehicle for gene delivery to odontoblasts through local injection. In addition, human OLCs were also successfully infected by AAV6 with high efficiency, and both AAVR and EGFR are strongly expressed in the odontoblast layer of extracted human developing teeth. These findings suggest that AAV6-mediated gene therapy through local injection may be a promising treatment approach for hereditary dentin disorders in humans.

Bone sialoprotein promotes lung cancer osteolytic bone metastasis via MMP14-dependent mechanisms.

Bone metastases during lung cancer are common. Bone sialoprotein (BSP), a non-collagenous bone matrix protein, plays important functions in bone mineralization processes and in integrin-mediated cell-matrix interactions. Importantly, BSP induces bone metastasis in lung cancer, but the underlying mechanisms remain unclear. This study therefore sought to determine the intracellular signaling pathways responsible for BSP-induced migration and invasion of lung cancer cells to bone. Analyses of the Kaplan-Meier, TCGA, GEPIA and GENT2 databases revealed that high levels of BSP expression in lung tissue samples were associated with significantly decreased overall survival (hazard ratio = 1.17; p = 0.014) and with a more advanced clinical disease stage (F-value = 2.38, p < 0.05). We also observed that BSP-induced stimulation of matrix metalloproteinase (MMP)-14 promoted lung cancer cell migration and invasion via the PI3K/AKT/AP-1 signaling pathway. Notably, BSP promoted osteoclastogenesis in RAW 264.7 cells exposed to RANKL and BSP neutralizing antibody reduced osteoclast formation in conditioned medium (CM) from lung cancer cell lines. Finally, at 8 weeks after mice were injected with A549 cells or A549 BSP shRNA cells, the findings revealed that the knockdown of BSP expression significantly reduced metastasis to bone. These findings suggest that BSP signaling promotes lung bone metastasis via its direct downstream target gene MMP14, which reveals a novel potential therapeutic target for lung cancer bone metastases.

Spatial regulation of the glycocalyx component podocalyxin is a switch for prometastatic function.

The glycocalyx component and sialomucin podocalyxin (PODXL) is required for normal tissue development by promoting apical membranes to form between cells, triggering lumen formation. Elevated PODXL expression is also associated with metastasis and poor clinical outcome in multiple tumor types. How PODXL presents this duality in effect remains unknown. We identify an unexpected function of PODXL as a decoy receptor for galectin-3 (GAL3), whereby the PODXL-GAL3 interaction releases GAL3 repression of integrin-based invasion. Differential cortical targeting of PODXL, regulated by ubiquitination, is the molecular mechanism controlling alternate fates. Both PODXL high and low surface levels occur in parallel subpopulations within cancer cells. Orthotopic intraprostatic xenograft of PODXL-manipulated cells or those with different surface levels of PODXL define that this axis controls metastasis in vivo. Clinically, interplay between PODXL-GAL3 stratifies prostate cancer patients with poor outcome. Our studies define the molecular mechanisms and context in which PODXL promotes invasion and metastasis.

A novel DSPP frameshift mutation causing dentin dysplasia type 2 and disease management strategies.

The present study aims to investigate the mutation in a Chinese family with dentin dysplasia type II (DD-II) and to summarize mutation hotspots, clinical manifestations, and disease management strategies. Phenotype analysis, clinical intervention, mutation screening, and cosegregation analysis within the enrolled family were performed. A summary of the reported mutations in the dentin phosphoprotein (DPP) region of dentin sialophosphoprotein (DSPP) was analyzed. Pathogenicity prediction analysis of the physical properties and function of DSPP variants was performed by bioinformatic processing. Clinical management strategies are discussed. A novel pathogenic mutation (c.2035delA) in the DPP region of DSPP was identified, which was cosegregated in the family. The immature permanent teeth of patients with DD-II presented with X-shaped root canal phenotypes. Most of the identified mutations for DD-II were clustered in the DPP region between nucleotides 1686-2134. Points of differential diagnosis, clinical interventions, and management strategies are proposed. This study revealed a novel DSPP frameshift mutation and presented new clinical features of DD-II. The locus involving nucleotides 1686-2134 of DSPP may represent a mutational hotspot for the disease. Appropriate management of DD-II at different stages is important to avoid the development of secondary dental lesions.

[Mutation of dentin sialophosphoprotein and hereditary malformations of dentin].

The classification as well as the clinical manifestations of hereditary malformations of dentin are of great concern and have been deeply elucidated. The understanding of its genetic basis also increases progressively. Dentin sialophosphoprotein (DSPP) is the pathogenic gene of dentinogenesis imperfecta type Ⅱ, dentinogenesis imperfecta type Ⅲ and dentin dysplasia type Ⅱ. In this article, the classification of DSPP mutations as well as the resultant dysfunction of the mutant DSPP are summarized respectively and the corresponding clinical manifestations are analyzed. This work will provide a reference for the diagnosis and treatment of hereditary malformations of dentin.

Tubular dentin formation by TGF-ß/BMP signaling in dental epithelial cells.

OBJECTIVES: This study aimed to identify formation of tubular dentin induced by transforming growth factor-ß (TGF-ß) and bone morphogenic protein (BMP) signaling pathway in dental epithelial cells. METHODS: We collected conditioned medium (CM) of rTGF-ß1/rBMP-2-treated HAT-7 and treated to MDPC-23 cells. The expression levels of odontoblast differentiation markers, KLF4, DMP1, and DSP were evaluated by real-time PCR and Western blot analysis. To evaluate whether CM of rTGF-ß1/rBMP-2 induces tubular dentin formation, we made a beagle dog tooth defect model. RESULTS: Here, we show that Cpne7 is regulated by Smad4-dependent TGF-ß1/BMP2 signaling pathway in dental epithelial cells. CM of rTGF-ß1/rBMP-2 treated HAT-7 or rCPNE7 raises the expression levels of KLF4, DMP1, and DSP in MDPC-23 cells. When rTGF-ß1 or rBMP-2 is directly treated to MDPC-23 cells, however, expression levels of Cpne7-regulated genes remain unchanged. In a beagle dog defect model, application of rTGF-ß1/BMP2-treated CM resulted in tubular tertiary dentin mixed with osteodentin at cavity-prepared sites, while rTGF-ß1 group exhibited homogenous osteodentin. CONCLUSIONS: Taken together, Smad4-dependent TGF-ß1/BMP2 signaling regulates Cpne7 in dental epithelial cells, and CPNE7 protein secreted from pre-ameloblasts mediates odontoblast differentiation via epithelial-mesenchymal interaction.

Biodentine but not MTA induce DSPP expression of dental pulp cells with different severity of LPS-induced inflammation.

OBJECTIVES: To explore the inflammatory and differentiation response in inflamed dental pulp cells (DPCs) induced by lipopolysaccharide (LPS) under different conditions with Biodentine and mineral trioxide aggregate (MTA) treatment. MATERIALS AND METHODS: DPCs were treated with 0.001-1 µg/mL LPS for different periods to induce inflammation. Normal and inflamed DPCs were further treated with 0.14 mg/mL Biodentine or 0.13 mg/mL MTA for different periods. mRNA expression level of IL-6, IL-8 and ALP were analysed by qPCR. DSPP protein expression was detected by western blot. The data were analysed by the Mann-Whitney test, unpaired t test or two-way ANOVA. RESULTS: After treatment for different times and with different concentrations of LPS, different severity of pulp inflammation was revealed by the expressions of IL-6 and IL-8. Higher concentrations of LPS induced higher IL-6 and IL-8 expressions, and these expressions first increased and then decreased (p < 0.0001). At 96 and 192 h, Biodentine significantly suppressed IL-6 expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine suppressed ALP expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine induced DSPP expressions in both normal and inflamed DPCs (p < 0.05). CONCLUSION: Biodentine enhanced more DSPP differentiation of both normal and inflamed DPCs under different treatment durations than MTA. CLINICAL RELEVANCE: The prognosis of vital pulp therapy may depend on the severity of pulp inflammation which is difficult to be determined in clinical settings. Therefore, Biodentine may enhance odontogenic differentiation in different severity of pulp inflammation imply its clinical indications.

A Cancer-Specific Monoclonal Antibody against Podocalyxin Exerted Antitumor Activities in Pancreatic Cancer Xenografts.

Podocalyxin (PODXL) overexpression is associated with poor clinical outcomes in various tumors. PODXL is involved in tumor malignant progression through the promotion of invasiveness and metastasis. Therefore, PODXL is considered a promising target of monoclonal antibody (mAb)-based therapy. However, PODXL also plays an essential role in normal cells, such as vascular and lymphatic endothelial cells. Therefore, cancer specificity or selectivity is required to reduce adverse effects on normal cells. Here, we developed an anti-PODXL cancer-specific mAb (CasMab), PcMab-6 (IgG1, kappa), by immunizing mice with a soluble PODXL ectodomain derived from a glioblastoma LN229 cell. PcMab-6 reacted with the PODXL-positive LN229 cells but not with PODXL-knockout LN229 cells in flow cytometry. Importantly, PcMab-6 recognized pancreatic ductal adenocarcinoma (PDAC) cell lines (MIA PaCa-2, Capan-2, and PK-45H) but did not react with normal lymphatic endothelial cells (LECs). In contrast, one of the non-CasMabs, PcMab-47, showed high reactivity to both the PDAC cell lines and LECs. Next, we engineered PcMab-6 into a mouse IgG2a-type (PcMab-6-mG2a) and a humanized IgG1-type (humPcMab-6) mAb and further produced the core fucose-deficient types (PcMab-6-mG2a-f and humPcMab-6-f, respectively) to potentiate the antibody-dependent cellular cytotoxicity (ADCC). Both PcMab-6-mG2a-f and humPcMab-6-f exerted ADCC and complement-dependent cellular cytotoxicity in the presence of effector cells and complements, respectively. In the PDAC xenograft model, both PcMab-6-mG2a-f and humPcMab-6-f exhibited potent antitumor effects. These results indicated that humPcMab-6-f could apply to antibody-based therapy against PODXL-expressing pancreatic cancers.

Derivatization of sialylated glycopeptides plus based sialoglycopeptides enrichment using cation exchange media.

Glycosylation is one of the most important post-translational modifications. However, the characterizations of glycopeptides, especially the negatively charged sialoglycopeptides that are associated with various diseases, remain challenging, due to the co-existence with high abundant peptides and the low ionization efficiency of sialoglycopeptides resulting from the carboxyl groups. Therefore, it is essential to develop an efficient enrichment method for sialoglycopeptides. Here, we present a novel derivatization-based enrichment method that can (i) identify linkage isomers of sialic acids by generating mass difference, (ii) unify the net charge of peptides into zero, and (iii) introduce positive charges to sialoglycopeptides by conjugating quaternary ammonium with sialic acid. The derivatization, termed derivatization of sialylated glycopeptides plus (DOSG+), enables efficient enrichment through electrostatic interaction using weak cation exchange (WCX) media. DOSG+ -based WCX enrichment was validated and optimized with samples derived from bovine fetuin. Peptides were removed efficiently (recovery rate <1%). The signal intensity of a selected model sialoglycopeptide was increased by ∼30% (suggesting recovery rate >100%). The method was employed on human alpha-1 acid glycoprotein (AGP), and recombinant human erythropoietin (EPO), demonstrating the application of DOSG+ -based WCX enrichment on complexed N-linked and O-linked sialoglycopeptides. The method is simple, efficient, and targets small-scale sialoglycopeptide enrichment.

Platelet-derived extracellular vesicles encapsulate microRNA-34c-5p to ameliorate inflammatory response of coronary artery endothelial cells via PODXL-mediated P38 MAPK signaling pathway.

BACKGROUND AND AIMS: Low-grade chronic inflammation was reported to serve as a distinctive pathophysiologic feature of coronary artery disease (CAD), the leading cause of death around the world. Herein, the current study aimed to explore whether and how microRNA-34c-5p (miR-34c-5p), a miRNA enriched in extracellular vesicles (EVs) originated from the activated platelet (PLT-EVs), affects the inflammation of human coronary artery endothelial cells (HCAECs). METHODS AND RESULTS: HCAECs were established as an in vitro cell model using oxidized low-density lipoprotein (ox-LDL). miR-34c-5p, an abundant miRNA in PLT-EVs, can be transferred to HCAECs and target PODXL by binding to its 3'UTR. Gain- and loss-of-function experiments of miR-34c-5p and podocalyxin (PODXL) were performed in ox-LDL-induced HCAECs. Subsequently, HCAECs were subjected to co-culture with PLT-EVs, followed by detection of the expression patterns of key pro-inflammatory factors. Either miR-34c-5p mimic or PLT-EVs harboring miR-34c-5p attenuated the ox-LDL-evoked inflammation in HCAECs by suppressing interleukin-1ß (IL-1ß), IL-6 and tumor necrosis factor-α (TNF-α). By blocking the P38 MAPK signaling pathway, miR-34c-5p-mediated depletion of PODXL contributed to protection against ox-LDL-induced inflammation. In vitro findings were further validated by findings observed in ApoE knock-out mice. Additionally, miR-34c-5p in PLT-EVs showed an athero-protective role in the murine model. CONCLUSION: Altogether, our findings highlighted that miR-34c-5p in PLT-EVs could alleviate inflammation response in HCAECs by targeting PODXL and inactivation of the P38 MAPK signaling pathway.

Novel Isobaric Tagging Reagent Enabled Multiplex Quantitative Glycoproteomics via Electron-Transfer/Higher-Energy Collisional Dissociation (EThcD) Mass Spectrometry.

Protein glycosylation, covalent attachment of carbohydrates to polypeptide chains, is a highly important post-translational modification involved in many essential physiological processes. Comprehensive site-specific and quantitative analysis is crucial for revealing the diverse functions and dynamics of glycosylation. To characterize intact glycopeptides, mass spectrometry (MS)-based glycoproteomics employs versatile fragmentation methods, among which electron-transfer/higher-energy collision dissociation (EThcD) has gained great popularity. However, the inherent limitation of EThcD in fragmenting low-charge ions has prevented its widespread applications. Furthermore, there is a need to develop a high-throughput strategy for comparative glycoproteomics with a large cohort of samples. Herein, we developed isobaric N,N-dimethyl leucine-derivatized ethylenediamine (DiLeuEN) tags to increase the charge states of glycopeptides, thereby improving the fragmentation efficiency and allowing for in-depth intact glycopeptide analysis, especially for sialoglycopeptides. Moreover, the unique reporter ions of DiLeuEN-labeled glycopeptides generated in tandem MS spectra enable relative quantification of up to four samples in a single analysis, which represents a new high-throughput method for quantitative glycoproteomics.

A WWP2-PTEN-KLF5 signaling axis regulates odontoblast differentiation and dentinogenesis in mice.

WW domain-containing E3 Ubiquitin-protein ligase 2 (WWP2) has been found to positively regulate odontoblastic differentiation by monoubiquitinating the transcription factor Kruppel-like factor 5 (KLF5) in a cell culture system. However, the in vivo role of WWP2 in mouse teeth remains unknown. To explore this, here we generated Wwp2 knockout (Wwp2 KO) mice. We found that molars in Wwp2 KO mice exhibited thinner dentin, widened predentin, and reduced numbers of dentinal tubules. In addition, expression of the odontoblast differentiation markers Dspp and Dmp1 was decreased in the odontoblast layers of Wwp2 KO mice. These findings demonstrate that WWP2 may facilitate odontoblast differentiation and dentinogenesis. Furthermore, we show for the first time that phosphatase and tensin homolog (PTEN), a tumor suppressor, is expressed in dental papilla cells and odontoblasts of mouse molars and acts as a negative regulator of odontoblastic differentiation. Further investigation indicated that PTEN is targeted by WWP2 for degradation during odontoblastic differentiation. We demonstrate PTEN physically interacts with and inhibits the transcriptional activity of KLF5 on Dspp and Dmp1. Finally, we found WWP2 was able to suppress the interaction between PTEN and KLF5, which diminished the inhibition effect of PTEN on KLF5. Taken together, this study confirms the essential role of WWP2 and the WWP2-PTEN-KLF5 signaling axis in odontoblast differentiation and dentinogenesis in vivo.

A novel mannose-containing sialoprotein adhesin involved in the binding of Candida albicans cells to DMBT1.

Candida albicans colonizes the oral cavity and causes oral candidiasis and early childhood caries synergistically with cariogenic Streptococcus mutans. Colonization of oral tissues with C. albicans is an essential step in the initiation of these infectious diseases. Deleted in malignant brain tumors 1 (DMBT1), also known as salivary agglutinin or gp-340, belongs to the scavenger receptor cysteine-rich (SRCR) superfamily and has important functions in innate immunity. In the oral cavity, DMBT1 causes microbial adherence to tooth enamel and oral mucosa surfaces, but the adherence of C. albicans to DMBT1 has not been examined. In this study, we investigated the binding of C. albicans to DMBT1 and isolated the fungal components responsible for the binding. Candida albicans specifically bound to DMBT1 and strongly bound to the peptide domain SRCRP2. Binding to SRCRP2 was inhibited by N-acetylneuraminic acid and mannose and by lectins recognizing these sugars. The isolated component had a molecular mass of 25 kDa, contained sialic acid and mannose residues, and inhibited C. albicans binding to SRCRP2. The localization of the 25-kDa protein on the surface of C. albicans cell walls was confirmed by immunostaining and a cell ELISA using an antiserum to the protein, and Western blotting revealed the presence of the 25-kDa protein in the cell wall fraction of C. albicans. These results suggest that the isolated adhesin is localized on the surface of C. albicans cell walls and that sialic acid and mannose residues in the adhesin play a significant role in the binding reaction.