The pro-apoptotic and pro-inflammatory effects of calprotectin on human periodontal ligament cells

Role of innate host defense proteins in oral cancerogenesis

It is nowadays well accepted that chronic inflammation plays a pivotal role in tumor initiation and progression. Under this aspect, the oral cavity is predestined to examine this connection because periodontitis is a highly prevalent chronic inflammatory disease and oral squamous cell carcinomas are the most common oral malignant lesions. In this review, we describe how particular molecules of the human innate host defense system may participate as molecular links between these two important chronic noncommunicable diseases (NCDs). Specific focus is directed toward antimicrobial polypeptides, such as the cathelicidin LL-37 and human defensins, as well as S100 proteins and alarmins. We report in which way these peptides and proteins are able to initiate and support oral tumorigenesis, showing direct mechanisms by binding to growth-stimulating cell surface receptors and/or indirect effects, for example, inducing tumor-promoting genes. Finally, bacterial challenges with impact on oral cancerogenesis are briefly addressed.

Calprotectin and periostin levels in periodontitis patients with coronary artery disease

OBJECTIVE

The aim of the study was to assess the effect of non-surgical periodontal therapy (NSPT) on periodontal and cardiac parameters as well as on the expression of calprotectin and periostin levels in periodontitis patients with and without coronary artery disease (CAD).

METHODS

Ninety subjects were categorised into three groups: Group H: periodontally and systemically healthy subjects, Group P: stage III grade B periodontitis subjects with no associated systemic diseases and Group P + CAD: stage III grade B periodontitis subjects diagnosed with CAD. Demographic, periodontal and cardiac parameters were recorded at baseline (0 day) and on the 180th day after NSPT. Gingival crevicular fluid was collected from all participants at baseline (0 day) and after the 180th day. Calprotectin and periostin expression were reassessed.

RESULTS

A significant increase in the levels of calprotectin (34.05 ± 11.72) was seen at baseline in the P + CAD group, whereas on the contrary, a decreased periostin (1.59 ± 0.41) was also noted at baseline. The study also showed a significant improvement in periodontal and cardiac parameters on the 180th day following NSPT.

CONCLUSION

Detection of calprotectin and periostin expression in GCF samples could represent a link to the association of periodontitis and CAD.

Insights into the Relationship between Periodontitis and Systemic Sclerosis Based on the New Periodontitis Classification (2018): A Cross-Sectional Study

(1) Background: This study aimed to assess the periodontitis burden in systemic sclerosis patients and the possible association between them, and the degree to which some potential risk factors and two potential diagnostic biomarkers may account for this association. (2) Methods: This cross-sectional study included a test group (systemic sclerosis patients) and a control group (non-systemic sclerosis patients). Both groups benefited from medical, periodontal examination and saliva sampling to determine the salivary flow rate and two inflammatory biomarkers (calprotectin, psoriasin). A systemic sclerosis severity scale was established. (3) Results: In the studied groups, comparable periodontitis rates of 88.68% and 85.85%, respectively, were identified. There were no significant differences in the severity of periodontitis among different systemic sclerosis severity, or in the positivity for anti-centromere and anti-SCL70 antibodies. Musculoskeletal lesions were significantly more common in stage III/IV periodontitis (n = 33, 86.84%) than in those in stage I/II (n = 1, 100%, and n = 3, 37.5%, respectively) (p = 0.007). Comparable levels of the inflammatory mediators were displayed by the two groups. There were no significant differences in calprotectin and psoriasin levels between diffuse and limited forms of systemic sclerosis. (4) Conclusions: Within the limitations of the current study, no associations between systemic sclerosis and periodontitis, or between their risk factors, could be proven.

Impact of Non-Surgical Periodontal Treatment on the Concentration and Level of MRP-8/14 (Calprotectin) as an Inflammatory Biomarker in Women with Periodontitis and Rheumatoid Arthritis: A Quasi-Experimental Study

The aim of this study was to evaluate the impact of non-surgical periodontal treatment (NS-PT) on periodontal parameters and inflammatory biomarkers in the concentration and level of calprotectin (CLP) in women with periodontitis and rheumatoid arthritis (RA). In this quasi-experimental study, we evaluated 30 women (mean age: 52.0 ± 5.8 years) with periodontitis and RA who had been diagnosed and treated for RA for more than 3 years and whose activity markers remained at similar values without significant reduction over three consecutive months. Patients underwent NS-PT, which included plaque control, scaling, and root planing. Serum and saliva samples, periodontal indices, RA activity markers, Disease Activity Score-28 (DAS28), the erythrocyte sedimentation rate (ESR), and the C-reactive protein (CRP) and CLP contents were measured at the beginning of the study and 6 and 12 weeks after NS-PT. Parametric and nonparametric tests were used in the analysis. The mean age was 52.0 ± 5.8 years. Compared to the baseline results, all periodontal indices were significantly reduced 6 and 12 weeks after NS-PT (p < 0.001). DAS28 was also significantly reduced after 12 weeks (p < 0.0001). Similarly, the serum CLP concentration decreased 6 and 12 weeks after NS-PT (p < 0.0001). Of the patients, 100% presented lower levels of CRP and ESR (p < 0.0001). Overall, NS-PT reduced inflammation and disease activity, highlighting the importance of oral health in the control and treatment of systemic diseases such as RA and confirming that NS-PT effectively reduces periodontitis activity and plays a key role in modulating RA activity. Therefore, NS-PT should be considered as an adjunct treatment for RA.

S100a9 deficiency accelerates MDS-associated tumor escape via PD-1/PD-L1 overexpression

In recent studies, the tolerable safety profile and positive bone marrow (BM) response suggest a beneficial use of anti-PD-1 agents in the treatment of Myelodysplastic Syndromes (MDS), but the underlying mechanism is still unknown. MDS is mainly characterized by ineffective hematopoiesis, which may contribute to inflammatory signaling or immune dysfunction. Our previous studies focused on inflammatory signaling, and the results showed that S100a9 expression was higher in low-risk MDS and lower in high-risk MDS. In this study, we combine the inflammatory signaling and immune dysfunction. SKM-1 cells and K562 cells co-cultured with S100a9 acquire apoptotic features. Moreover, we confirm the inhibitory effect of S100a9 on PD-1/PD-L1. Importantly, PD-1/PD-L1 blockade and S100a9 can both activate the PI3K/AKT/mTOR signaling pathway. The cytotoxicity is higher in lower-risk MDS-lymphocytes than in high-risk MDS-lymphocytes, and S100a9 partially rescues the exhausted cytotoxicity in lymphocytes. Our study demonstrates that S100a9 may inhibit MDS-associated tumor escape via PD-1/PD-L1 blockade through PI3K/AKT/mTOR signaling pathway activation. Our findings indicate the possible mechanisms by which anti-PD-1 agents may contribute to the treatment of MDS. These insights may provide mutation-specific treatment as a supplementary therapy for MDS patients with high-risk mutations, such as TP53, N-RAS or other complex mutations.

Decreased S100A9 expression alleviates Clostridium perfringens beta2 toxin-induced inflammatory injury in IPEC-J2 cells

Background

S100 calcium-binding protein A9 (S100A9) is a commonly known pro-inflammatory factor involved in various inflammatory responses. Clostridium perfringens (C. perfringens ) type C is known to cause diarrhea in piglets. However, the role of S100A9 in C. perfringens type C-induced infectious diarrhea is unclear.

Methods

Here, the S100A9 gene was overexpressed and knocked down in the IPEC-J2 cells, which were treated with C. perfringens beta2 (CPB2) toxin. The role of S100A9 in CPB2 toxin-induced injury in IPEC-J2 cells was assessed by measuring the levels of inflammatory cytokines, reactive oxygen species (ROS), lactate dehydrogenase (LDH), cell proliferation, and tight junction-related proteins.

Results

The results showed elevated expression of S100A9 in diarrhea-affected piglet tissues, and the elevation of S100A9 expression after CPB2 toxin treatment of IPEC-J2 was time-dependent. In CPB2 toxin-induced IPEC-J2 cells, overexpression of S100A9 had the following effects: the relative expression of inflammatory factors IL-6, IL8, TNF-α, and IL-1β was increased; the ROS levels and LDH viability were significantly increased; cell viability and proliferation were inhibited; the G0/G1 phase cell ratio was significantly increased. Furthermore, overexpression of S100A9 reduced the expression of tight junction proteins in CPB2-induced IPEC-J2 cells. The knockdown of S100A9 had an inverse effect. In conclusion, our results confirmed that S100A9 exacerbated inflammatory injury in CPB2 toxin-induced IPEC-J2 cells, inhibited cell viability and cell proliferation, and disrupted the tight junctions between cells. Thus, decreased S100A9 expression alleviates CPB2 toxin-induced inflammatory injury in IPEC-J2 cells.

Expression of S100A9 and KL-6 in common interstitial lung diseases

By evaluating S100 calcium binding protein A9 (S100A9) and Klebs von den Lungen-6 (KL-6) expression in patients with 4 common interstitial lung diseases (ILDs), we aimed to investigate whether S100A9 or KL-6 can be of any value in the differential diagnosis of these ILDs and simultaneously signal the disease progression.We collected the data of patients diagnosed with the 4 ILDs and underwent fiber-optic bronchoscopy and BAL in the First Affiliated Hospital, China Medical University from January 2012 to December 2020. The data related to BGA, C-reactive protein, pulmonary function test, total number and fraction of cells, T lymphocyte subsets in bronchoalveolar lavage fluid (BALF), and the expression of S100A9 and KL-6 in BALF and serum were collected. We analyzed, whether S100A9 or KL-6 could serve as a biomarker for differential diagnosis between the 4 common ILDs; whether the levels of S100A9 and KL-6 correlated with each other; whether they were correlated with other clinical parameters and disease severity.This study included 98 patients, 37 patients with idiopathic pulmonary fibrosis (IPF), 12 with hypersensitivity pneumonitis, 13 with connective tissue disease-associated ILD, and 36 with sarcoidosis (SAR): stage I (18), stage II (9), stage III (5), and stage IV (4). The expression of KL-6 in BALF was significantly higher in IPF patients than other 3 groups (all P-value < .05). However, there was no significant difference in the levels of S100A9 in BALF and serum between the 4 groups (P-value > .05). The levels of S100A9 in BALF of IPF patients was positively and significantly correlated with KL-6 expression and the percentage of neutrophils in BALF (P-value < .05). Along with the stage increase of SAR patients, the level of S100A9 in BALF gradually increased, which was negatively and significantly correlated with the forced vital capacity/predicted, carbon monoxide diffusing capacity/predicted%, and PaO2 (all P-value < .05).The expression of KL-6 in BALF can be used as a biomarker to differentiate IPF from the other 3 common ILDs. While, this was not the case with expression of S100A9 in BALF and serum. However, the expression S100A9 in BALF is useful to indicate the progression of SAR. Thus, simultaneous measurement of KL-6 and S100A9 levels in BALF makes more sense in differential diagnosing of the 4 common ILDS.

The protective effect of NF-κB signaling pathway inhibitor PDTC on mice with chronic atrophic gastritis

OBJECTIVE

To understand the protective effect of NF-κB signaling pathway inhibitor pyrrolidinedithiocarbamate (PDTC) on mice with chronic atrophic gastritis (CAG).

METHODS

Helicobacter pylori (H. pylori) infection combined with high-salt diet was used to construct the CAG mouse model, and 100 or 200 mg/kg/day PDTC was intragastrically treated for 8 weeks. Then, hematoxylin and eosin (HE) and Alcian blue-periodic acid-Schiff (AB-PAS) staining were used to observe the pathology of gastric mucosa, while immunohistochemistry, quantitative real-time polymerase chain reaction (qRT-PCR), enzyme-linked immuno sorbent assay (ELISA) and western blotting were determined to detect the expression of related molecules.

RESULTS

The nuclear content of NF-κB p65 in the gastric mucosa of the CAG mice was increased accompanying by the structural disorder of the gastric mucosal epithelium, inflammatory cell infiltration, intestinal metaplasia, and increased MUC2 expression, but the symptoms were alleviated after PDTC treatment. In addition, the expressions of TNF-α, IL-1β, IL-6 and COX2 in the gastric mucosa and serum of CAG mice were higher than those control mice, which were reduced in CAG mice treated with either 100 or 200 mg/kg PDTC. Furthermore, 100 mg/kg and 200 mg/kg PDTC treatments reduced the serum PGE₂ in CAG mice with the decreased PCNA and Ki-67 expression in gastric mucosa. The therapeutic effect of 200 mg/kg PDTC was significantly better than that of 100 mg/kg PDTC.

CONCLUSION

PDTC inhibited inflammation and the excessive proliferation of gastric mucosal epithelial cells, thereby exerting a potential therapeutic effect on CAG.

S100A8 and S100A9 in saliva, blood and gingival crevicular fluid for screening established periodontitis: a cross-sectional study

Background

Periodontitis is one of major oral diseases, which has no consensus on early screening tool. This study aimed to compare the association and screening ability of S100A8 and S100A9 in saliva, blood and gingival crevicular fluid (GCF) for periodontitis status.

Methods

We recruited 149 community Korean adults, 50 no or initial periodontitis (NIPERIO) and 99 established periodontitis (PERIO). Using clinical attachment loss and a panoramic radiograph, stage II–IV of new classification of periodontitis proposed at 2018 was considered cases as PERIO. Enzyme linked immunosorbent assay kit was used to quantify S100A8 and S100A9. T-test, analysis of covariance, Mann–Whitney test and correlation analysis were applied to compare the relationship of S100A8 and S100A9 in saliva, blood, and GCF for periodontitis. Receiver operating characteristic curve was applied for screening ability.

Results

Among S100A8 and S100A9 in saliva, blood and GCF, S100A8 in saliva was significantly higher in PERIO than in NIPERIO (p < 0.05). However, S100A8 and S100A9 in GCF were higher in NIPERIO (p < 0.05). The screening ability of salivary S100A8 was 75% for PERIO, while that of GCF S100A8 was 74% for NIPERIO. Salivary S100A8 was positively correlated to blood S100A8 (p < 0.05).

Conclusion

Salivary S100A8 could be a potential diagnostic marker for established periodontitis and be useful for screening established periodontitis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01749-z.

S100A9 induces nucleus pulposus cell degeneration through activation of the NF-κB signaling pathway

Oxidative stress in the lumbar disc leads to the degeneration of nucleus pulposus (NP). However, the molecular mechanisms underlying this process remain unclear. In this study, we delineated a key calcium-binding protein, S100A9, which was induced by oxidative stress and was highly expressed in the degenerative NP. Immunofluorescence staining and Western blotting revealed that S100A9 induced NP cell apoptosis in vitro by up-regulating the expression of pro-apoptotic markers, including cleaved caspase-3, cytochrome c and Bax. Moreover, RT-PCR analyses revealed that the expression of S100A9 caused NP matrix degradation by up-regulating the expression of matrix degradation enzymes and increased the inflammatory response by up-regulating cytokine expression. Therefore, S100A9 induced NP cell degeneration by exerting pro-apoptotic, pro-degradation and pro-inflammatory effects. The detailed mechanism underlying S100A9-induced NP degeneration was explored by administering SC75741, a specific NF-κB inhibitor in vitro. We concluded that S100A9 induced NP cell apoptosis, caused matrix degradation and amplified the inflammatory response through the activation of the NF-κB signalling pathway. Inhibition of these pro-apoptotic, pro-degradation and pro-inflammatory effects induced by S100A9 in NP may be a favourable therapeutic strategy to slow lumbar disc degeneration.

Calprotectin in Lung Diseases

Calprotectin (CLP) is a heterodimer formed by two S-100 calcium-binding cytosolic proteins, S100A8 and S100A9. It is a multifunctional protein expressed mainly by neutrophils and released extracellularly by activated or damaged cells mediating a broad range of physiological and pathological responses. It has been more than 20 years since the implication of S100A8/A9 in the inflammatory process was shown; however, the evaluation of its role in the pathogenesis of respiratory diseases or its usefulness as a biomarker for the appropriate diagnosis and prognosis of lung diseases have only gained attention in recent years. This review aimed to provide current knowledge regarding the potential role of CLP in the pathophysiology of lung diseases and describe how this knowledge is, up until now, translated into daily clinical practice. CLP is involved in numerous cellular processes in lung health and disease. In addition to its anti-microbial functions, CLP also serves as a molecule with pro- and anti-tumor properties related to cell survival and growth, angiogenesis, DNA damage response, and the remodeling of the extracellular matrix. The findings of this review potentially introduce CLP in daily clinical practice within the spectrum of respiratory diseases.

Calprotectin levels in gingival crevicular fluid and serum of patients with chronic periodontitis and type 2 diabetes mellitus before and after initial periodontal therapy

BACKGROUND

This study is aimed to compare the total amount of calprotectin in gingival crevicular fluid (GCF) and the concentration of calprotectin in serum among the patients with type 2 diabetes mellitus and chronic periodontitis (DM-P), the patients with chronic periodontitis (CP) and the healthy controls, as well as the variation of these indicators before and three months after the initial periodontal therapy for the DM-P patients.

METHODS

35 patients with DM-P patients, 32 patients with CP patients, and 43 healthy controls were recruited. Calprotectin levels in serum and GCF, periodontal parameters, fasting blood glucose (FBG), and HbA1c were measured at baseline for all the groups and three months after the initial periodontal therapy for the DM-P patients.

RESULTS

At baseline, the calprotectin levels in GCF and serum were the highest in DM-P, followed by CP, and the lowest in healthy controls. GCF calprotectin was significantly and positively correlated with serum calprotectin and probing depth (PD), while serum calprotectin had a significant positive correlation with GCF calprotectin and HbA1c. Periodontal parameters, HbA1c, and serum and GCF calprotectin became significantly reduced after the initial periodontal treatment. The reduction of serum calprotectin was consistent with that of HbA1c, while the decrease of GCF calprotectin was in agreement with that of PD, attachment loss (AL), and bleeding on probing (BOP).

CONCLUSIONS

The levels of calprotectin in serum and GCF in the DM-P patients are significantly higher than those in CP patients and healthy controls, which significantly reduced 3 months after the initial periodontal therapy. Furthermore, it suggests diabetic patients might exhibit more pronounced inflammation periodontally and systemically.

S100A9 plays a pivotal role in a mouse model of herpetic neuralgia via TLR4/TNF pathway

Herpetic neuralgia is a painful condition following herpes zoster disease, which results from Varicella-zoster virus reactivation in the dorsal or trigeminal sensory ganglia. Nevertheless, the pathophysiological mechanisms involved in herpetic neuralgia are not well understood. Recently, we identified, that neuroimmune-glia interactions in the sensory ganglion is a critical mechanism for the development of herpetic neuralgia. Here, we investigate the contribution of S100A9, a well-known pro-inflammatory molecule produced by myeloid cells, for the development of herpetic neuralgia using a murine model of HSV-1 infection. We found that cutaneous HSV-1 infection results in an increase of S100A9 expression in the Dorsal Root Ganglia (DRGs). Infiltrating neutrophils into the DRGs were the main source of S100A9 post HSV-1 infection. Functionally, genetic or pharmacological inhibition of S100A9 impairs the development of HSV-1 infection-induced mechanical pain hypersensitivity. Finally, we found that the pronociceptive role of S100A9 in herpetic neuralgia depends on the TLR4/TNF pathway. These results unraveled previously unknown mechanisms involved in the pathophysiology of herpetic neuralgia and indicate that S100A9 might be an important target for novel therapies aiming acute herpetic neuralgia.

Calprotectin (S100A8/S100A9)-induced cytotoxicity and apoptosis in human gastric cancer AGS cells: Alteration in expression levels of Bax, Bcl-2, and ERK2

Calprotectin is a heterodimeric EF-hand Ca²⁺ binding protein that is typically released by infiltrating polymorphonuclear leukocytes and macrophages. This protein is a key player linking inflammation and cancer. Due to the increased levels of calprotectin in different inflammatory diseases and cancer, it is considered as a marker for diagnostic purposes. In this study, we evaluated the mechanism of cell viability and apoptotic-inducing effects of recombinant human calprotectin (rhS100A8/S100A9) on the gastric adenocarcinoma (AGS), the most common type of gastric cancer cell line. AGS cells were exposed to the different concentrations (5-100 μg/ml) of calprotectin for 24, 48, and 72 h, and cell viability was assessed through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Apoptotic-inducing effects of calprotectin were evaluated by sub-G1 cell cycle assay and Annexin V/propidium iodide double staining. Furthermore, real-time polymerase chain reaction and Western blot analysis were performed to evaluate the mechanism of action of calprotectin. Our findings indicated that calprotectin inhibits growth and viability of AGS cells in a time- and dose-dependent manner. The half-maximal inhibitory concentration values were measured as 85.77, 79.14, and 65.39 μg/ml for 24, 48, and 72 h, respectively. Additionally, we found that calprotectin downregulated the expression of antiapoptotic protein Bcl-2 and upregulated proapoptotic protein Bax in a time- and concentration-dependent fashion. Calprotectin also slightly upregulated the expression of extracellular signal-regulated protein kinase 2 (ERK2), while it significantly decreased the levels of phospho-ERK in a time-dependent manner. Overall, these findings indicated that calprotectin has cytotoxicity and apoptosis-inducing effects on AGS cell lines in high concentration by modulating Bax/Bcl-2 expression ratio accompanied by inhibition of ERK activation.

S100A9 Increases IL-6 and RANKL Expressions through MAPKs and STAT3 Signaling Pathways in Osteocyte-Like Cells

Objective

Calprotectin is a heterocomplex of S100A8 and S100A9 and is mainly secreted from neutrophils, monocytes, and chondrocytes in inflammatory condition. Calprotectin binds to RAGE and TLR4 and induces the expression of proinflammatory chemokines and cytokines in various cells. Periodontitis is a chronic inflammatory disease that leads to gingival inflammation and alveolar bone resorption. Calprotectin levels in gingival crevicular fluid of periodontitis patients are higher than healthy patients. In the present study, the effects of S100A8 and S100A9 on the expressions of proinflammatory cytokines and bone metabolism-related factors in mouse osteocyte-like cells (MLO-Y4-A2) were investigated.

Design

MLO-Y4-A2 cells were treated with S100A8 and S100A9, and the expressions of RAGE, TLR4, RANKL, and several inflammatory cytokines were analyzed by PCR and Western blotting or ELISA methods. To investigate the intracellular signaling pathways, phosphorylation of MAPK and STAT3 was determined by Western blotting, and chemical specific inhibitors and siRNAs were used.

Results

Expressions of IL-6 and RANKL were increased by treatment with S100A9 but not S100A8. However, both S100A8 and S100A9 did not change expression of IL-1β, IL-8, and TNF-α. Although RAGE and TLR4 expressions were not upregulated by S100A9 treatment, transfection of siRNA for RAGE and TLR4 significantly decreased IL-6 and RANKL expressions. In addition, S100A9 activated p38, ERK, and STAT3 signaling pathways, and inhibitors for these factors significantly decreased S100A9-induced IL-6 and RANKL expressions.

Conclusions

These results indicated that S100A9 induces IL-6 and RANKL production via engagement with RAGE and TLR4 signalings in osteocytes and suggested that S100A9 may play important roles in the periodontal alveolar bone destruction.

Role of Calprotectin as a Biomarker in Periodontal Disease

Periodontal disease (PD) is a common infectious and inflammatory disease characterised by inflammation of tissues surrounding and supporting the teeth and destruction of the associated alveolar bone, eventually resulting in tooth loss. This disease is caused by periodontopathic bacteria in plaque biofilm and resultant innate and adaptive immune responses in periodontal tissues. Calprotectin (CLP) is a calcium-binding protein of the S-100 protein family and is found to be induced by activated granulocytes, monocytes, and epithelial cells. CLP has been shown to play an important role in numerous inflammatory diseases and disorders. Increasing evidence indicates that CLP is involved in the progression of PD, and its levels may be associated with disease severity and outcome of periodontal treatments. This review will summarise recent studies regarding the presence, regulation, and function of CLP in PD. The findings indicate that CLP may be an effective biomarker for diagnosis and treatment for the PD.

Apoptosis Transcriptional Profile Induced by Porphyromonas gingivalis HmuY

This study aimed at evaluating the transcriptional profile of apoptosis-related genes after in vitro stimulation of peripheral blood mononuclear cells (PBMCs) derived from individuals with periodontitis (P) and healthy nonperiodontitis (NP) control subjects with P. gingivalis HmuY protein. PBMCs from the P and NP groups were stimulated with HmuY P. gingivalis protein, and the expression of genes related to apoptosis was assessed by custom real-time polymerase chain reaction array (Custom RT2 PCR Array). Compared with the NP group, the P group showed low relative levels of apoptosis-related gene expression, downregulated for FAS, FAS ligand, TNFSF10 (TRAIL), BAK1, CASP9, and APAF1 after P. gingivalis HmuY protein stimulation. Furthermore, the P group exhibited low levels of relative gene expression, downregulated for CASP7 when the cells were not stimulated. Our data suggest that P. gingivalis HmuY protein might participate differently in the modulation of the intrinsic and extrinsic apoptosis pathways.

Proinflammatory Effects of Calprotectin in Graves' Orbitopathy

Purpose: Early detection and control of inflammation are important to manage Graves' orbitopathy (GO). We investigated the effects of calprotectin (S100A8/A9) on orbital fibroblast inflammation and GO pathogenesis.Methods: We measured serum calprotectin, S100A8 and S100A9 mRNA expression in orbital fat/connective tissue from GO patients and healthy controls, and proinflammatory cytokines in primary cultured orbital fibroblasts.Results: The serum levels of S100A8/A9 and the expression of S100A8/A9 mRNA in orbital tissue were higher in the GO patients than in the healthy controls. The serum calprotectin levels positively correlated with the clinical activity score and serum thyroid-stimulating immunoglobulin levels. In cultured GO orbital fibroblasts, S100A8/A9 increased the expression of interleukin (IL)-6, IL-8, and monocyte chemotactic protein-1, as well as the phosphorylation of extracellular signal-regulated kinase and nuclear factor-κB.Conclusion: We demonstrated the potential of calprotectin as a biomarker of GO severity and proinflammatory responses to S100A8/A9 in GO orbital fibroblasts.

Calprotectin (S100A8/S100A9): a key protein between inflammation and cancer

BACKGROUND

Calprotectin (S100A8/S100A9), a heterodimeric EF-hand Ca²⁺ binding protein, are abundant in cytosol of neutrophils and are involved in inflammatory processes and several cancerous pathogens.

OBJECTIVE

The purpose of the present systematic review is to evaluate the pro- and anti-tumorigenic functions of calprotectin and its relation to inflammation.

MATERIALS AND METHODS

We conducted a review of studies published in the Medline (1966-2018), Scopus (2004-2018), ClinicalTrials.gov (2008-2018) and Google Scholar (2004-2018) databases, combined with studies found in the reference lists of the included studies.

RESULTS

Elevated levels of S100A8/S100A9 were detected in inflammation, neoplastic tumor cells and various human cancers. Recent data have explained that many cancers arise from sites of infection, chronic irritation, and inflammation. The inflammatory microenvironment which largely includes calprotectin, has an essential role on high producing of inflammatory factors and then on neoplastic process and metastasis.

CONCLUSION

Scientists have shown different outcomes in inflammation, malignancy and apoptosis whether the source of the aforementioned protein is extracellular or intracellular. These findings are offering new insights that anti-inflammatory therapeutic agents and anti-tumorigenic functions of calprotectin can lead to control cancer development.

MMP-12 and S100s in saliva reflect different aspects of periodontal inflammation

Matrix metalloproteinase (MMP)-12, S100A8/A9, and S100A12 are involved in innate immune responses. We addressed whether different aspects of oral health and non-disease-related covariates influence their levels in saliva. 436 participants were clinically examined, completed a health questionnaire, and provided stimulated saliva. Salivary levels of MMP-12, S100A8/A9, and S100A12 were determined by enzyme-linked immunosorbent assays. Lower MMP-12 levels were observed in individuals 40-64 years old (yo) compared to < 40 yo, and higher S100A8/A9 levels were found in individuals > 64 yo compared to 40-64 yo. Smokers exhibited lower MMP-12 and S100A12 levels compared to non-smokers. All three proteins were elevated in individuals with bleeding on probing (BOP) > 20% compared to those with BOP ≤ 20%, and the S100A8/A9 levels were higher in individuals having ≥ 10% gingival pocket depths (PPD) ≥ 4 mm compared to the ones with shallow pockets < 4 mm. The extent of alveolar bone loss or presence of manifest caries did not alter any of the markers. MMP-12, S100A8/A9, and S100A12 levels were higher in participants with high periodontal inflammatory burden. All three proteins correlated positively to BOP, PPD, and to several inflammatory mediators. The explanatory variables for MMP-12 in saliva were age, smoking, presence of any tumor, and percentage of PPD ≥ 4 mm. The determinant of salivary S100A8/A9 was percentage of BOP, while S100A12 levels were associated with percentage of BOP and presence of any tumor. Taken together, MMP-12 and the S100/calgranulin levels in saliva reflect different aspects of periodontal inflammation. Smoking and age should be taken into account in further investigation of these proteins as biomarker candidates of periodontal disease.

Proinflammatory effects and mechanisms of calprotectin on human gingival fibroblasts

BACKGROUND AND OBJECTIVE

Calprotectin (S100A8/A9) is a heterodimer of S100A8 and S100A9 and is associated with multiple inflammatory diseases, including Crohn's disease, rheumatoid arthritis and periodontitis. Levels of calprotectin are elevated in the gingival crevicular fluid of patients with periodontitis; however, the effects of calprotectin on human gingival fibroblasts (HGFs) remain unknown. This study investigated the proinflammatory activity of calprotectin on HGFs and the functional receptors and signaling pathways engaged by calprotectin.

MATERIAL AND METHODS

HGFs were stimulated by equimolar concentrations of S100A8 and/or S100A9, and the expression levels of interleukin (IL)-6 and IL-8 were detected using real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assays. The calprotectin receptors were identified by pre-incubating HGFs with the toll-like receptor (TLR) 4 inhibitor or the antibody targeting the advanced glycation end product receptor (RAGE). The involvement of reactive oxygen species (ROS) and signaling pathways were also investigated by treating HGFs with ROS inhibitor or specific pathway inhibitors, respectively.

RESULTS

S100A9 and S100A8/A9 significantly upregulated IL-6 and IL-8 expression, which was inhibited upon treatment with the TLR4 inhibitor TAK242. Pretreatment with RAGE-blocking antibodies did not affect cytokine expression. Additionally, S100A9 promoted the production of IL-6 and IL-8 from HGFs via different signaling pathways. IL-6 expression was upregulated via the NF-κB, c-Jun amino-terminal kinase (JNK) 1/2 and p38 mitogen-activated protein kinase (MAPK) pathways, and IL-8 expression was upregulated via NF-κB, p38, JNK1/2 and extracellular-regulated kinase 1/2 MAPK pathways. The release of both cytokines was dependent upon the production of ROS.

CONCLUSION

Our findings suggest that calprotectin exerts proinflammatory effects on HGFs via the S100A9 subunit and TLR4-mediated NF-κB and MAPK signaling pathways.

Calprotectin Induces IL-6 and MCP-1 Production via Toll-Like Receptor 4 Signaling in Human Gingival Fibroblasts

Calprotectin, a heterodimer of S100A8 and S100A9 molecules, is associated with inflammatory diseases such as inflammatory bowel disease. We have reported that calprotectin levels in gingival crevicular fluids of periodontitis patients are significantly higher than in healthy subjects. However, the functions of calprotectin in pathophysiology of periodontitis are still unknown. The aim of this study is to investigate the effects of calprotectin on the productivity of inflammatory cytokines in human gingival fibroblasts (HGFs). The HGFs cell line CRL-2014® (ATCC) were cultured, and total RNAs were collected to examine the expression of TLR2/4 and RAGE mRNA using RT-PCR. After the cells were treated with S100A8, S100A9, and calprotectin, supernatants were collected and the levels of IL-6 and MCP-1 were measured using ELISA methods. To examine the intracellular signals involved in calprotectin-induced cytokine production, several chemical inhibitors were used. Furthermore, after the siRNA-mediated TLR4 down-regulated cells were treated with S100A8, S100A9, and calprotectin, the levels of IL-6 and MCP-1 were also measured. HGFs showed greater expression of TLR4 mRNA, but not TLR2 and RAGE mRNA compared with human oral epithelial cells. Calprotectin increased significantly the production of MCP-1 and IL-6 in HGFs, and the cytokine productions were significantly suppressed in the cells treated with MAPKs, NF-κB, and TLR4 inhibitors. Furthermore, calprotectin-mediated MCP-1 and IL-6 production were significantly suppressed in TLR4 down-regulated cells. Taken together, calprotectin induces IL-6 and MCP-1 production in HGFs via TLR4 signaling that involves MAPK and NF-κB, resulting in the progression of periodontitis. J. Cell. Physiol. 232: 1862-1871, 2017. © 2016 Wiley Periodicals, Inc.

Programmed cell death in periodontitis: recent advances and future perspectives

Periodontitis is a highly prevalent infectious disease, characterized by destruction of the periodontium, and is the main cause of tooth loss. Periodontitis is initiated by periodontal pathogens, while other risk factors including smoking, stress, and systemic diseases aggravate its progression. Periodontitis affects many people worldwide, but the molecular mechanisms by which pathogens and risk factors destroy the periodontium are unclear. Programmed cell death (PCD), different from necrosis, is an active cell death mediated by a cascade of gene expression events and can be mainly classified into apoptosis, autophagy, necroptosis, and pyroptosis. Although PCD is involved in many inflammatory diseases, its correlation with periodontitis is unclear. After reviewing the relevant published articles, we found that apoptosis has indeed been reported to play a role in periodontitis. However, the role of autophagy in periodontitis needs further verification. Additionally, implication of necroptosis or pyroptosis in periodontitis remains unknown. Therefore, we recommend future studies, which will unravel the pivotal role of PCD in periodontitis, allowing us to prevent, diagnose, and treat the disease, as well as predict its outcomes.

Serum Calprotectin Expression as a Diagnostic Marker for Sepsis in Postoperative Intensive Care Unit Patients

The research was performed to explore the diagnosis value of dynamic serum calprotectin (SC) expression for sepsis in postoperative intensive care unit patients. One hundred sixty-three patients who met the inclusion criteria served as the study group. All cases in the study group were further divided into the sepsis subgroup (51 cases) and the nonsepsis subgroup (112 cases). Fifty healthy volunteers served as the control group. The levels of SC and other laboratory indexes including complete blood counts, leukocytes, the immature-to-total-neutrophil ratio, procalcitonin (PCT), C-reactive protein, and blood lactate were detected, cytokines [interleukin (IL)-2, IL-6, and interferon-γ] released by neutrophils were also determined. The Acute Physiology and Chronic Health Evaluation II (APACHE II) score and the Sequential Organ Failure Assessment score were calculated. The factors related to prognosis were analyzed with multivariate logistic regression analysis. The diagnostic accuracies of ΔSC [the differences of SC levels between postoperative day (POD) 1 and POD 2, 3, 5, 7] and ΔPCT (the differences of PCT levels between POD 1 and POD 2, 3, 5, 7) on sepsis were compared with other markers for sepsis. The levels of SC and cytokines were markedly increased on POD 1, 2, 3, 5, and 7 in the study group compared with the control group (P < 0.05 or P < 0.01). The same results were found in the sepsis subgroup compared with the nonsepsis subgroup (P < 0.05 or P < 0.01). Significant positive correlations between SC and cytokines were confirmed in patients of the study group (P < 0.05 or P < 0.01). APACHE II scores and the levels of SC and PCT on POD 1 were the variables significantly associated with sepsis. The diagnostic accuracies of ΔSC_1-3 (sensitivity 87%, specificity 89%) and ΔPCT_1-3 (sensitivity 89%, specificity 90%) for sepsis were greater than other ΔSCs and ΔPCTs. It appears that the dynamic changes in SC are of the predictive values for septic patients after major surgeries.

[Expression and effect of S100A9 in the periodontium of diabetic rats]

OBJECTIVE

The study seeks to investigate the expression of S100A9 and its potential role in periodontal diseases induced by diabetes.

METHODS

A diabetic SD rat model was established through intraperitoneal injection of streptozotocin (STZ). Hematoxylin-eosin (HE) staining was performed to study the structure of the periodontium of diabetic rats. Using immunohistochemical staining, the distribution of S100A9 expression was detected in the periodontium of diabetic rats. Ex-pressions of Toll-like receptor 4 (TLR4) (ligands of S100A9) and p-P65/nuclear factor κB (NF-κB) were also measured.

RESULTS

The trabecular structure of alveolar bone was sparser, and lamina dura was disappeared in diabetic rats. Obviously higher expressions of S100A9 were observed in the periodontal ligament, alveolar bone, and gingival epithelial of diabetic rats than in the control rats. TLR4 expressions in the periodontal ligament, alveolar bone and gingival epithelial of the diabetic rats were also higher as compared to the control rats. p-P65 expression was not detected in the control rats, but was detected in the periodontal ligament and alveolar bone of the diabetic rats.

CONCLUSIONS

Periodontium lesions in diabetes mellitus may be induced by the activation of TLR4 and NF-κB signaling pathway meditated by S100A9. 
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Insight into the maintenance of odontogenic potential in mouse dental mesenchymal cells based on transcriptomic analysis

Background. Mouse dental mesenchymal cells (mDMCs) from tooth germs of cap or later stages are frequently used in the context of developmental biology or whole-tooth regeneration due to their odontogenic potential. In vitro-expanded mDMCs serve as an alternative cell source considering the difficulty in obtaining primary mDMCs; however, cultured mDMCs fail to support tooth development as a result of functional failures of specific genes or pathways. The goal of this study was to identify the genes that maintain the odontogenic potential of mDMCs in culture.

Methods. We examined the odontogenic potential of freshly isolated versus cultured mDMCs from the lower first molars of embryonic day 14.5 mice. The transcriptome of mDMCs was detected using RNA sequencing and the data were validated by qRT-PCR. Differential expression analysis and pathway analysis were conducted to identify the genes that contribute to the loss of odontogenic potential.

Results. Cultured mDMCs failed to develop into well-structured tooth when they were recombined with dental epithelium. Compared with freshly isolated mDMCs, we found that 1,004 genes were upregulated and 948 were downregulated in cultured mDMCs. The differentially expressed genes were clustered in the biological processes and signaling pathways associated with tooth development. Following in vitro culture, genes encoding a wide array of components of MAPK, TGF-β/BMP, and Wnt pathways were significantly downregulated. Moreover, the activities of Bdnf, Vegfα, Bmp2, and Bmp7 were significantly inhibited in cultured mDMCs. Supplementation of VEGFα, BMP2, and BMP7 restored the expression of a subset of downregulated genes and induced mDMCs to form dentin-like structures in vivo.

Conclusions.Vegfα, Bmp2, and Bmp7 play a role in the maintenance of odontogenic potential in mDMCs.

Calprotectin in rheumatic diseases

Calprotectin is a heterodimer formed by two proteins, S100A8 and S100A9, which are mainly produced by activated monocytes and neutrophils in the circulation and in inflamed tissues. The implication of calprotectin in the inflammatory process has already been demonstrated, but its role in the pathogenesis, diagnosis, and monitoring of rheumatic diseases has gained great attention in recent years. Calprotectin, being stable at room temperature, is a candidate biomarker for the follow-up of disease activity in many autoimmune disorders, where it can predict response to treatment or disease relapse. There is evidence that a number of immunomodulators, including TNF-α inhibitors, may reduce calprotectin expression. S100A8 and S100A9 have a potential role as a target of treatment in murine models of autoimmune disorders, since the direct or indirect blockade of these proteins results in amelioration of the disease process. In this review, we will go over the biologic functions of calprotectin which might be involved in the etiology of rheumatic disorders. We will also report evidence of its potential use as a disease biomarker. Impact statement Calprotectin is an acute-phase protein produced by monocytes and neutrophils in the circulation and inflamed tissues. Calprotectin seems to be more sensitive than CRP, being able to detect minimal residual inflammation and is a candidate biomarker in inflammatory diseases. High serum levels are associated with some severe manifestations of rheumatic diseases, such as glomerulonephritis and lung fibrosis. Calprotectin levels in other fluids, such as saliva and synovial fluid, might be helpful in the diagnosis of rheumatic diseases. Of interest is also the potential role of calprotectin as a target of treatment.

Analysis of protein expression in periodontal pocket tissue: a preliminary study

Background

The periodontal disease is caused by a set of inflammatory disorders characterized by periodontal pocket formation that lead to tooth loss if untreated. The proteomic profile and related molecular conditions of pocket tissue in periodontally-affected patients are not reported in literature. To characterize the proteomic profile of periodontally-affected patients, their interproximal periodontal pocket tissue was compared with that of periodontally-healthy patients. Pocket-associated and healthy tissue samples, harvested during surgical therapy, were treated to extract the protein content. Tissues were always collected at sites where no periodontal-pathogenic bacteria were detectable. Proteins were separated using two-dimensional gel electrophoresis and identified by liquid chromatography/mass spectrometry. After identification, four proteins were selected for subsequent Western Blot quantitation both in pathological and healty tissues.

Results

A significant unbalance in protein expression between healthy and pathological sites was recorded. Thirty-two protein spots were overall identified, and four proteins (S100A9, HSPB1, LEG7 and 14-3-3) were selected for Western blot analysis of both periodontally-affected and healthy patients. The four selected proteins resulted over-expressed in periodontal pocket tissue when compared with the corresponding tissue of periodontally-healthy patients. The results of Western blot analysis are congruent with the defensive and the regenerative reaction of injured periodontal tissues.

Conclusions

The proteomic analysis was performed for the first time directly on periodontal pocket tissue. The proteomic network highlighted in this study enhances the understanding of periodontal disease pathogenesis necessary for specific therapeutic strategies setting.

Impact of nicotine on the interplay between human periodontal ligament cells and CD4+ T cells

Periodontitis is a common infectious disease associated with destruction of periodontal ligaments and alveolar bones. CD4(+) T cell-mediated immune response is involved in the progression of periodontitis. Tobacco consumption increases the risk of periodontal disease. However, the impact of nicotine on the interaction between human periodontal ligament (PDL) cells and CD4(+) T cells remains unrevealed. Our study aims to investigate the effect of nicotine on PDL cells and the cocultured CD4(+) T cells. The PDL cell cultures were established by explants from healthy individuals, exposed to nicotine or α-bungarotoxin (α-BTX), and incubated solely or in combination with CD4(+) T cells. Afterwards, cell viability, secreted cytokines, and matrix metalloproteinases (MMPs) were evaluated. In monoculture of PDL cells, nicotine dramatically repressed cell viability and increased apoptosis. Meanwhile, α-BTX largely reversed the nicotine-induced apoptosis and increased viability of PDL cells. Compared with the monoculture, MMP-1, MMP-3, interleukin (IL)-1β, IL-6, IL-17, and IL-21 in supernatant of cocultures were markedly elevated after treatment with nicotine. Moreover, α-BTX significantly attenuated nicotine-triggered production of these components either in mono- or co-cultures. In addition, PDL cell-derived CXCL12 following nicotine treatment recruited CD4(+) T cells. Above all, nicotine deteriorated periodontitis partially by promoting PDL cell-CD4(+) T cell-mediated inflammatory response and matrix degradation.

S100A9-induced release of interleukin (IL)-6 and IL-8 through toll-like receptor 4 (TLR4) in human periodontal ligament cells

S100A8, S100A9, and calprotectin (the S100A8/S100A9 complex) are calcium-binding proteins that promote extracellular pro-inflammatory functions and may play an important role in periodontal disease. Both toll-like receptor 4 (TLR4) and the receptor for advanced glycation end-products (RAGE) are thought to be important receptors for S100A8, S100A9, and calprotectin, but the specific pathways in periodontal ligament (PDL) cells are not yet clear. Our study was designed to identify the specific receptors for S100A9 in human PDL cells. Additionally, we investigated the specific pathways that activate the secretion of pro-inflammatory cytokines interleukins (IL)-6 and IL-8 in PDL cells. The role of nuclear factor (NF)-κB, mitogen-activated protein kinase (MAPK) and reactive oxygen species (ROS) in S100A9-induced pro-inflammatory cytokines were investigated through western blot analysis, dichlorodihydrofluorescein diacetate (H2DCFDA) probe and the application of specific pathway inhibitors. Our results suggest that the S100A9-induced release of IL-6 and IL-8 from human PDL cells is dependent on TLR4, but not RAGE. We provide evidence that S100A9 promotes the secretion of IL-6 and IL-8 through different pathways. Specifically, S100A9 up-regulates the secretion of IL-6 from human PDL cells through NF-κB and p38 pathways and up-regulates the release of IL-8 from human PDL cells through the NF-κB, extracellular-regulated kinase (ERK) 1/2, c-Jun amino-terminal kinase (JNK) 1/2, and p38 signaling pathways. In addition, the release of both cytokines depends on ROS production. The release of both cytokines depends on ROS production. These results suggest that S100A9 promotes pro-inflammatory responses in PDL cells through the TLR4-mediated NF-κB and MAPK signaling pathways.