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

Multiparameter diagnostic model using S100A9, CCL5 and blood biomarkers for nasopharyngeal carcinoma

This study aimed to analyze S100A9 and CCL5 levels in patients with nasopharyngeal carcinoma (NPC) and evaluate their predictive value as blood-based indicators for NPC diagnosis. Serum S100A9 and CCL5 levels were measured in 123 patients newly diagnosed with NPC and 107 patients without NPC. Additionally, 38 patients (19 with NPC and 19 without) were recruited from Xiangya Hospital as an external validation cohort. Logistic regression was used to identify risk factors for NPC. Variable selection was conducted using least absolute shrinkage and selection operator (LASSO) regression. NPC prediction models were developed using four machine-learning algorithms, and their performance was evaluated with ROC curves. Calibration curves, decision curve analysis (DCA), and Shapley additive explanation plots were employed for further evaluation and interpretation. Serum S100A9 and CCL5 levels were significantly elevated in patients with NPC compared with patients without NPC. Multivariate logistic regression identified S100A9, CCL5, TP, and ALB as independent predictors of NPC. ROC analysis demonstrated that S100A9 had superior diagnostic performance compared to CCL5 and other blood indicators, effectively differentiating NPC from non-NPC cases. A machine-learning-based logistic regression model incorporating S100A9, CCL5, ALB, GLB, and PLR demonstrated a reliable diagnostic value for NPC, achieving an Area under the curve (AUC) of 0.877 in the training cohort. The calibration curve showed excellent agreement between predicted and actual probabilities; in contrast, the DCA curve highlighted strong clinical utility. The model also performed well in the external validation cohort, with an AUC of 0.817. Serum levels of S100A9, CCL5, and other indicators such as GLB, ALB, and PLR have diagnostic values for NPC. The logistic regression model based on these biomarkers demonstrated robust predictive performance and clinical utility for NPC diagnosis.

S100A8 regulates postoperative responses following tooth extraction in rats

The reduction in alveolar ridge height and width after tooth extraction poses a substantial challenge for dental implant restoration. This study aimed to observe the roles of S100A8 in the inflammatory response and bone resorption following tooth extraction. Rat mandibular second molars were extracted. Western blotting, micro-computed tomography, tartrate-resistant acid phosphatase staining, immunohistochemistry, scanning electron microscopy (SEM), and immunofluorescence were applied to observe inflammatory responses and bone resorption after rat mandibular second molar extraction. S100A8 was overexpressed in RAW 246.7 cells, and transfection efficiency was confirmed using western blotting and immunofluorescence. Receptor Activator for Nuclear Factor-κB Ligand (RANKL)-induced osteoclastogenesis of RAW 246.7 cells and a lipopolysaccharide-stimulated environment were chosen to evaluate the roles and related mechanisms of S100A8. An increase in S100A8 expression was observed 2 weeks after molar extraction compared to normal gingival tissues. Subsequently, S100 expression decreased between the second and third weeks, coinciding with the progression of inflammatory response following tooth extraction. Positive S100A8 expression was detected in the infiltrating cells and osteoclasts. S100A8 overexpression in RAW 246.7 cells promoted tumor necrosis factor-α expression and osteoclast formation by activating nuclear factor (NF)-κB p65 signaling. In summary, S100A8 was involved in inflammatory responses and bone resorption following tooth extraction by activating NF-κB p65 signaling. Interventions targeted to decrease S100A8 levels may have therapeutic implications for minimizing post-extraction bone loss.

Polypeptide of Inonotus hispidus extracts alleviates periodontitis through suppressing inflammatory bone loss

This study aimed to characterize and evaluate the effects of a novel polypeptide isolated from Inonotus hispidus (IH) against periodontitis. The polypeptides extracted and purified from the fruiting body of IH had a uniform molar mass, including 23 types of peptides. IH polypeptide (IHP) exerted antimicrobial activity against Porphyromonas gingivalis (P. gingivalis) by damaging the cell walls and membranes of microorganisms, disturbing energy metabolism, and regulating the expression of virulence factors. IHP significantly inhibited inflammation in lipopolysaccharides (LPS)-stimulated Raw264.7 cells evidenced by the regulation of inflammatory cytokine levels. In rats with ligature-induced periodontitis, IHP treatment ameliorated alveolar bone destruction and preserved the balance between oral flora and gut microbes. The interaction between oral and intestinal flora possibly affected the relevant metabolites. Proteomics combined with confirmation experiment revealed that the β-catenin/ nuclear factor-kappa B (NF-κB) signaling may be involved in IHP-mediated anti-periodontitis in rats, which helps reduce the secretion of pro-inflammatory factors and inhibit inflammatory osteoclastic response in the periodontal tissue. Additionally, IHP improved clinical parameters, including the plaque index (PLI), pocket depth (PD), bleeding on probing (BOP), and average probing depth in individuals with periodontitis. These findings augment the understanding of the potential role of IHP in treating periodontitis.

Trained innate immunity as a potential link between preeclampsia and future cardiovascular disease

Preeclampsia (PE) is a complex pregnancy syndrome characterized by hypertension with or without proteinuria, affecting 2-6% of pregnancies globally. PE is characterized by excessive release of damage-associated molecular patterns (DAMPs) into the maternal circulation. This DAMP-rich milieu acts on innate immune cells, inducing a proinflammatory state characterized by elevated cytokines such as IL-1β and IL-18. This proinflammatory state in the mother and placenta results in the endothelial dysfunction strongly associated with cardiovascular disorders. While the immediate maternal and fetal risks of PE are well-documented, accumulating evidence indicates that PE also confers long-term cardiovascular risks to the mother, including hypertension, coronary heart disease, stroke, and heart failure. The underlying mechanisms connecting PE to these chronic cardiovascular conditions remain unclear. This article explores the potential role of trained innate immunity (TRIM) as a mechanistic link between PE and increased long-term cardiovascular risk. We propose that the persistent exposure to DAMPs during PE may epigenetically reprogram maternal innate immune cells and their progenitors, leading to TRIM. This reprogramming enhances the inflammatory response to subsequent stimuli, potentially contributing to endothelial dysfunction and chronic inflammation that predispose women to cardiovascular diseases later in life. Understanding the role of TRIM in PE could provide novel insights into the pathophysiology of PE-related cardiovascular complications and identify potential targets for therapeutic intervention. Further research is warranted to investigate the epigenetic and metabolic alterations in innate immune cells induced by PE and to determine how these changes may influence long-term maternal cardiovascular health.

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.

Anti-inflammatory effects of hesperidin on human gingival fibroblasts stimulated by lipopolysaccharide of Porphyromonas gingivalis in vitro

Periodontal disease is an inflammatory disease caused by periodontopathogenic bacteria, the inflammatory response generated against them, and host factors. Furthermore, environmental factors can lead to disease progression. Using lipopolysaccharide (LPS)-stimulated human gingival fibroblast (HGF), this study investigated the bioactivity of HGF after exposure to hesperidin (Hesp) and the anti-inflammatory activity of Hesp against early periodontitis. HGF were cultured in Dulbecco's modified Eagle's medium containing 15% fetal bovine serum. They were exposed to LPS for 6 h, followed by Hesp (1, 10, 30, and 50 µM) exposure for 4 h. Cell proliferation was evaluated using reduction staining with alamerBlue™. Inflammatory cytokines [interleukin (IL)-6 and IL-8] and Toll-like receptor 4 (TLR4) levels were assessed using reverse transcription quantitative polymerase chain reaction. Hesp 50 µM + LPS inhibited cell proliferation. The Hesp exposure group inhibited the expression of IL-8 and IL-6. No significant difference in TLR4 expression was observed. Hesp significantly suppressed IL-6 and IL-8 expression by inhibiting downstream signaling without inhibiting TLR4 activation.

Role of serum calprotectin in identifying familial Mediterranean fever attacks

BACKGROUND/AIM

The aim of the study was to evaluate serum calprotectin (CLP) levels in familial Mediterranean fever (FMF) patients and to investigate the utility of CLP in distinguishing patients with attack from patients without attack.

MATERIAL AND METHOD

FMF patients, rheumatoid arthritis (RA) patients, and healthy controls were included. Serum calprotectin levels were quantified utilizing the enzyme-linked immunosorbent assay (ELISA) method. Receiver operating characteristic (ROC) curve analysis was used to identify the cut-off value of serum CLP level to differentiate FMF patients with attack from those without. Logistic regression analysis was performed to identify predictors.

RESULTS

Significant differences were observed among the three groups concerning white blood cell (WBC), neutrophil, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum CLP levels (p = 0.003, p = 0.004, p < 0.001, p < 0.001, and p = 0.002, respectively). Higher ESR, CRP, and serum CLP levels were observed in FMF patients with attacks than those without (all, p < 0.001). Serum CLP was significantly higher in RA patients than in FMF patients in remission (p < 0.001). ROC analysis identified a threshold CLP concentration in FMF with an attack to be 47.1 pg/mL (83.3% sensitivity, 60.6% specificity, AUC = 0.74, 95% CI = 0.63-0.85, p < 0.001). In univariate logistic regression analysis, CLP (β = 1.045, 95% CI = 1.017-1.073, p = 0.001) was predictive of FMF patients experiencing an attack.

CONCLUSION

Serum CLP proves to be as productive as ESR in illustrating inflammation and demonstrating the existence of attacks in FMF patients.

Calprotectin as a new inflammatory marker of abdominal aortic aneurysm: A pilot study

INTRODUCTION

Abdominal aortic aneurysm (AAA) is a relevant clinical problem due to the risk of rupture of progressively dilated infrarenal aorta. It is characterized by degradation of elastic fibers, extracellular matrix, and inflammation of the arterial wall. Though neutrophil infiltration is a known feature of AAA, markers of neutrophil activation are scarcely analyzed; hence, the main objective of this study.

METHODS

Plasma levels of main neutrophil activation markers were quantified in patients with AAA and a double control group (CTL) formed by healthy volunteers (HV) and patients with severe atherosclerosis submitted for carotid endarterectomy (CE). Calprotectin, a cytoplasmic neutrophil protein, was quantified, by Western blot, in arterial tissue samples from patients with AAA and organ donors. Colocalization of calprotectin and neutrophil elastase was assessed by immunofluorescence.

RESULTS

Plasma calprotectin and IL-6 were both elevated in patients with AAA compared with CTL (p ⩽ 0.0001) and a strong correlation was found between both molecules (p < 0.001). This difference was maintained when comparing with HV and CE for calprotectin but only with HV for IL-6. Calprotectin was also elevated in arterial tissue samples from patients with AAA compared with organ donors (p < 0.0001), and colocalized with neutrophils in the arterial wall.

CONCLUSIONS

Circulating calprotectin could be a specific AAA marker and a potential therapeutical target. Calprotectin is related to inflammation and neutrophil activation in arterial wall and independent of other atherosclerotic events.

Roles of S100A8, S100A9 and S100A12 in infection, inflammation and immunity

S100 proteins are small proteins that are only expressed in vertebrates. They are widely expressed in many different cell types and are involved in the regulation of calcium homeostasis, glucose metabolism, cell proliferation, apoptosis, inflammation and tumorigenesis. As members of the S100 protein subfamily of myeloid-related proteins, S100A8, S100A9 and S100A12 play a crucial role in resisting microbial infection and maintaining immune homeostasis. These proteins chelate the necessary metal nutrients of pathogens invading the host by means of 'nutritional immunity' and directly inhibit the growth of pathogens in the host. They interact with receptors on the cell surface to initiate inflammatory signal transduction, induce cytokine expression and participate in the inflammatory response and immune regulation. Furthermore, the increased content of these proteins during the pathological process makes them useful as disease markers for screening and detecting related diseases. This article summarizes the structure and function of the proteins S100A8, S100A9 and S100A12 and lays the foundation for further understanding their roles in infection, immunity and inflammation, as well as their potential applications in the prevention and treatment of infectious diseases.

Inhibition of S100A9 alleviates neurogenic pulmonary edema after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Neurogenic pulmonary edema (NPE) frequently arises as a complication subsequent to subarachnoid hemorrhage (SAH). Heterodimers of S100A8 and S100A9 are commonly formed, thereby initiating an inflammatory reaction through receptor binding on the cell surface. Paquinimod serves as a specific inhibitor of S100A9. The objective of this investigation is to assess the impact of Paquinimod administration and S100A9 knockout on NPE following SAH.

METHODS

In this study, SAH models of C57BL/6J wild-type (WT) and S100A9 knockout mice were established through intravascular perforation. These models were then divided into several groups, including the WT-sham group, S100A9-KO-sham group, WT-SAH group, WT-SAH + Paquinimod group, and S100A9-KO-SAH group. After 24 h of SAH induction, pulmonary edema was assessed using the lung wet-dry weight method and Hematoxylin and eosin (HE) staining. Additionally, the expression levels of various proteins, such as interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α), occludin, claudin-3, Bax, Bcl-2, TLR4, MYD88, and pNF-κB, in lung tissue were analyzed using western blot and immunofluorescence staining. Lung tissue apoptosis was detected by TUNEL staining.

RESULTS

Firstly, our findings indicate that the knockout of S100A9 has a protective effect on early brain injury following subarachnoid hemorrhage (SAH). Additionally, the reduction of brain injury after SAH can also alleviate neurogenic pulmonary edema (NPE). Immunofluorescence staining and western blot analysis revealed that compared to SAH mice with wild-type S100A9 expression (WT-SAH), the lungs of S100A9 knockout SAH mice (S100A9-KO-SAH) and mice treated with Paquinimod exhibited decreased levels of inflammatory molecules (IL-1β and TNF-α) and increased levels of tight junction proteins. Furthermore, the knockout of S100A9 resulted in upregulated expression of the apoptotic-associated protein Bax and down-regulated expression of Bcl-2. Furthermore, a decrease in TLR4, MYD88, and phosphorylated pNF-κB was noted in S100A9-KO-SAH and Paquinimod treated mice, indicating the potential involvement of the TLR4/MYD88/NF-κB signaling pathway in the inhibition of the protective effect of S100A9 on NPE following SAH.

CONCLUSION

The knockout of S100A9 not only ameliorated initial cerebral injury following subarachnoid hemorrhage (SAH), but also mitigated SAH-associated neurogenic pulmonary edema (NPE). Additionally, Paquinimod was found to diminish NPE. These findings imply a correlation between the central nervous system and peripheral organs, highlighting the potential of safeguarding the brain to mitigate harm to peripheral organs.

Decreased expression of S100A8/A9 in V30M related ATTRv amyloidosis

INTRODUCTION

Hereditary Transthyretin Amyloidosis is a rare, progressive and life-threatening systemic disease with predominant peripheral and autonomic nervous system involvement caused by mutation of the transthyretin protein. The most common TTR mutation regarding to ATTRv is a substitution of a Methionine for a Valine at position 30 that predisposes TTR to form aggregates and fibrils.

METHODS

S100A8 protein levels were measured in plasma samples from ATTRV30M patients and healthy donors. Additionally, S100A8/9 levels were measured in Schwann cells after incubation with human WT or V30M TTR. Moreover, bone marrow derived macrophages of either genetic background were generated and the expression of S100A8/9 was measured in response to toll like receptors agonists.

RESULTS

S100A8/A9 mRNA levels are decreased in HSF V30M mice as compared with the WT. Moreover, S100A8 protein levels were found downregulated in plasma samples from ATTRV30M patients. Furthermore, we provide evidence for a dysregulated S100 expression by Schwann cells in response to TTRV30M and by mutated macrophages in response to toll like receptors agonists.

CONCLUSION

The presence of TTRV30M impacts S100 expression, possibly contributing to the impaired immune activation of Schwann cells in nerves from ATTRV30M patients. This may be linked to the diminished immune cellular infiltration in these nerves, contributing in this way for the neuronal dysfunction present in the disease.

Glutamine supplementation accelerates functional recovery of EDL muscles after injury by modulating the expression of S100 calcium-binding proteins

The aim of the current study was to investigate the effect of glutamine supplementation on the expression of HSP70 and the calcium-binding proteins from the S100 superfamily in the recovering extensor digitorum longus (EDL) muscle after injury. Two-month-old Wistar rats were subjected to cryolesion of the EDL muscle and then randomly divided into two groups (with or without glutamine supplementation). Starting immediately after the injury, the supplemented group received daily doses of glutamine (1 g/kg/day, via gavage) for 3 and 10 days orally. Then, muscles were subjected to histological, molecular, and functional analysis. Glutamine supplementation induced an increase in myofiber size of regenerating EDL muscles and prevented the decline in maximum tetanic strength of these muscles evaluated 10 days after injury. An accelerated upregulation of myogenin mRNA levels was detected in glutamine-supplemented injured muscles on day 3 post-cryolesion. The HSP70 expression increased only in the injured group supplemented with glutamine for 3 days. The increase in mRNA levels of NF-κB, the pro-inflammatory cytokines IL-1β and TNF-α, and the calcium-binding proteins S100A8 and S100A9 on day 3 post-cryolesion in EDL muscles was attenuated by glutamine supplementation. In contrast, the decrease in S100A1 mRNA levels in the 3-day-injured EDL muscles was minimized by glutamine supplementation. Overall, our results suggest that glutamine supplementation accelerates the recovery of myofiber size and contractile function after injury by modulating the expression of myogenin, HSP70, NF-κB, pro-inflammatory cytokines, and S100 calcium-binding proteins.

Role of lymphoid lineage cells aberrantly expressing alarmins S100A8/A9 in determining the severity of COVID-19

BACKGROUND

Alarmins S100A8 and S100A9 are recognized as hallmarks of severe COVID-19 and are primarily produced in myeloid cells, such as monocytes and neutrophils. As single-cell RNA-sequencing (scRNA-seq) data from patients with COVID-19 revealed the expression of S100A8/A9 in lymphoid cells in patients with severe COVID-19.

OBJECTIVE

We investigated the characteristics of lymphoid cells expressing S100A8/A9 in COVID-19 patients.

METHODS

Publicly available scRNA-seq data from patients with mild (N = 12) or severe (N = 7) COVID-19 were reanalyzed. The data were further divided into the following two groups based on the time of sample collection (from infection-onset): within 6 days (early phase) and after 6 days (late phase). Differential expression and gene set enrichment analyses were performed between S100A8/A9^High and S100A8/A9^Low lymphoid cells. Finally, cell-cell interaction analysis was performed to investigate the role of lymphoid cells expressing high levels of S100A8/A9 in COVID-19.

RESULTS

S100A8/A9 overexpression was observed in lymphoid cells, including B cells, T cells, and NK cells, in patients with severe COVID-19 (compared to patients with mild COVID-19). Cells exhibiting strong interferon/cytokine responses were found to be associated with the severity of COVID-19. Furthermore, differences in S100A8/A9-TLR4/RAGE interactions were confirmed between patients with severe and mild disease.

CONCLUSIONS

Lymphoid cells overexpressing S100A8/A9 contribute to the dysregulation of the innate immune response in patients with severe COVID-19, specifically during the early phase of infection. This study fosters a better understanding of the hyper-induction of pro-inflammatory cytokine expression and the generation of a cytokine storm in response to COVID-19 infection.

Effects of Candidalysin Derived from Candida albicans on the Expression of Pro-Inflammatory Mediators in Human Gingival Fibroblasts

Candida albicans (Ca) is frequently detected in the peri-implant sulcus with peri-implantitis, a major postoperative complication after oral implant therapy. However, the involvement of Ca in the pathogenesis of peri-implantitis remains unclear. In this study, we aimed to clarify Ca prevalence in the peri-implant sulcus and investigated the effects of candidalysin (Clys), a toxin produced by Ca, on human gingival fibroblasts (HGFs). Peri-implant crevicular fluid (PICF) was cultured using CHROMagar and Ca colonization rate and colony numbers were calculated. The levels of interleukin (IL)-1β and soluble IL-6 receptor (sIL-6R) in PICF were quantified by enzyme-linked immunosorbent assay (ELISA). Pro-inflammatory mediator production and intracellular signaling pathway (MAPK) activation in HGFs were measured by ELISA and Western blotting, respectively. The Ca colonization rate and the average number of colonies in the peri-implantitis group tended to be higher than those in the healthy group. IL-1β and sIL-6R levels in the PICF were significantly higher in the peri-implantitis group than in the healthy group. Clys significantly induced IL-6 and pro-matrix metalloproteinase (MMP)-1 productions in HGFs, and co-stimulation with Clys and sIL-6R increased IL-6, pro-MMP-1, and IL-8 production levels in HGFs compared with Clys stimulation alone. These findings suggest that Clys from Ca plays a role in the pathogenesis of peri-implantitis by inducing pro-inflammatory mediators.

S100A8 alarmin supports IL-6 and metalloproteinase-9 production by fibroblasts in the synovial microenvironment of peripheral spondyloarthritis

Introduction

Spondyloarthritis (SpA) is a common autoinflammatory disease. S100A8/ S100A9 alarmin is strongly expressed in the synovial sublining layers of psoriatic arthritis. S100A8/ S100A9 is the most abundant protein in rheumatoid arthritis synovial fluid (SF) and has a key role in promoting IL-6 expression in fibroblast-like synoviocytes (FLS). The molecular mechanisms and the role of S100-alarmins in the synovial microenvironment of SpA have never been demonstrated.

Methods and Results

Here, we confirm the effect of the synovial microenvironment of peripheral SpA on interleukin-6 (IL-6) and metalloproteinase (MMP)-9 production by FLS. MMP-9 expression and activity were detected, which were reduced in the presence of anti-IL-6R. Analyzing cell signaling mechanisms, we found that stimulation with IL-6 co-triggered MMP-9 and IL-10 secretion. MMP-9 secretion depended on JNK and p38 MAPKs, whereas IL-10 secretion was dependent on the JAK pathway as a potential feedback mechanism controlling IL-6-induced MMP-9 expression. Using a proteomic approach, we identified S100A8 in the peripheral SpA SF. This presence was confirmed by immunoblotting. S100A8 increased the IL-6 secretion via ERK and p38 MAPK pathways. Furthermore, anti-S100A8/A9 reduced both IL-6 and MMP-9 production induced by SpA SF in FLS.

Discussion

Our data reveal a marked relationship between S100A8 alarmin with IL-6 and MMP-9 secretion by FLS in the real synovial microenvironment of peripheral SpA. These results identify a mechanism linking S100A8 to the pathogenesis of peripheral SpA.

Fibroblast ferroptosis is involved in periodontitis-induced tissue damage and bone loss

Periodontitis causes inflammatory destructions of tooth-supporting tissue and constitutes a significant burden on public health. Failing to reserve the tissue damage and bone loss by any of the currently available therapies has left periodontitis uncurable thus far. Understanding the molecular mechanism in the inflammatory process is crucial to elucidating the pathogenesis and enlightening new therapeutic strategies for periodontitis. This study was to investigate whether and how ferroptosis, a newly-discovered form of cell death, was involved in the pathogenesis of periodontitis. Healthy and periodontitis human gingiva samples were collected and ligature-induced periodontitis murine models were constructed to investigate the role of ferroptosis in periodontitis. Single-cell RNA sequencing data was analyzed to identify the cell type that underwent ferroptosis. The susceptibility of human gingival fibroblasts to ferroptosis was investigated by in vitro cell cultures. We found that gingival fibroblasts undergo ferroptosis in periodontitis, and that periodontitis-induced tissue damage and bone loss were alleviated by inhibition of ferroptosis. Periodontitis-induced pro-inflammatory immune responses was featured by profound elevation of fibroblast-derived Interleukin-6, which was attenuated by ferroptosis inhibition. These results indicated fibroblast ferroptosis as a new clue to unveiling the cellular and molecular basis for periodontitis-induced tissue damage. Involvement of ferroptosis/Interleukin-6 signaling in the pathogenic process suggested a potential target for immunopharmacological approaches to curing periodontitis.

Interleukin 6/gp130 axis promotes neural invasion in pancreatic cancer

BACKGROUND

Nerve invasion (N-inv) is an important prognostic factor in pancreatic ductal adenocarcinoma (PDAC). Elucidation of circulating N-inv stimulators could provide deeper insights and novel perspectives for PDAC therapy. The interleukin (IL)-6/gp130 axis was evaluated in this study as a candidate N-inv stimulator.

METHODS

A human pancreatic cancer (PC) cell, Capan-1, was confirmed to have the stimulant activity of IL-6/gp130 axis through the evaluation of mRNA, cell surface protein and intracellular protein levels and chemotaxis and wound healing assay. The upregulation of IL-6/gp130 axis was evaluated using tumor-derived IL-6 level and intratumoral pSTAT3 expression in N-inv of murine sciatic nerves by intraneural injection of Capan-1 cell (N-inv model) and using resected pancreatic cancer tissue and clinical data from 46 PDAC patients.

RESULTS

mRNA and protein expressions of IL-6 and IL-6 receptor were found in whole cell lysate and condition medium from PC cell. Cell surface protein expression of gp130 were clearly detected on PC cell. IL-6 promoted migration and chemotaxis of PC cell. Serum IL-6 and tumoral IL-6 mRNA levels in N-inv model mice were significantly higher than those in subcutaneous tumor mice (p = 0.004 and p = 0.002, respectively). Silencing of IL-6 and gp130 on PC cell and administration of an anti-IL-6 receptor antibody, tocilizumab, suppressed N-inv, compared to each control (p = 0.070, p = 0.118 and p = 0.122, respectively). In PDAC patients, the high-N-inv group showed poor prognosis (p =0.059) and elevated serum levels of IL-6 and C-reactive protein, synthesis of which is promoted by IL-6, compared to those in the low-N-inv group (p = 0.006 and p = 0.075, respectively). Tumoral gp130 expression at N-inv was higher than that in the primary pancreatic tumor (p = 0.026).

CONCLUSION

Biological activity of IL-6/gp130 axis promoted N-inv in murine model and was upregulated in PDAC patients with severe N-inv. This study is the first evidence that the IL-6/gp130 axis offers a potential therapeutic target in PDAC with N-inv.

Biological Roles of Fibroblasts in Periodontal Diseases

Periodontal diseases include periodontitis and gingival overgrowth. Periodontitis is a bacterial infectious disease, and its pathological cascade is regulated by many inflammatory cytokines secreted by immune or tissue cells, such as interleukin-6. In contrast, gingival overgrowth develops as a side effect of specific drugs, such as immunosuppressants, anticonvulsants, and calcium channel blockers. Human gingival fibroblasts (HGFs) are the most abundant cells in gingival connective tissue, and human periodontal ligament fibroblasts (HPLFs) are located between the teeth and alveolar bone. HGFs and HPLFs are both crucial for the remodeling and homeostasis of periodontal tissue, and their roles in the pathogenesis of periodontal diseases have been examined for 25 years. Various responses by HGFs or HPLFs contribute to the progression of periodontal diseases. This review summarizes the biological effects of HGFs and HPLFs on the pathogenesis of periodontal diseases.

A single-dose Qβ VLP vaccine against S100A9 protein reduces atherosclerosis in a preclinical model

The standard therapy for cardiovascular disease (CVD) is the administration of statins to reduce plasma cholesterol levels, but this requires lifelong treatment. We developed a CVD vaccine candidate that targets the pro-inflammatory mediator calprotectin by eliciting antibodies against the S100A9 protein. The vaccine, based on bacteriophage Qβ virus-like particles (VLPs) displaying S100A9 peptide epitopes, was formulated as a slow-release PLGA:VLP implant by hot-melt extrusion. The single-dose implant elicited S100A9-specific antibody titers comparable to a three-dose injection schedule with soluble VLPs. In an animal model of CVD (ApoE-/- mice fed on a high-fat diet), the implant reduced serum levels of calprotectin, IL-1β, IL-6 and MCP-1, resulting in less severe aortic lesions. This novel implant was therefore able to attenuate atherosclerosis over a sustained period and offers a novel and promising strategy to replace the repetitive administration of statins for the treatment of CVD.

Antimicrobial peptides: Defending the mucosal epithelial barrier

The recent epidemic caused by aerosolized SARS-CoV-2 virus illustrates the importance and vulnerability of the mucosal epithelial barrier against infection. Antimicrobial proteins and peptides (AMPs) are key to the epithelial barrier, providing immunity against microbes. In primitive life forms, AMPs protect the integument and the gut against pathogenic microbes. AMPs have also evolved in humans and other mammals to enhance newer, complex innate and adaptive immunity to favor the persistence of commensals over pathogenic microbes. The canonical AMPs are helictical peptides that form lethal pores in microbial membranes. In higher life forms, this type of AMP is exemplified by the defensin family of AMPs. In epithelial tissues, defensins, and calprotectin (complex of S100A8 and S100A9) have evolved to work cooperatively. The mechanisms of action differ. Unlike defensins, calprotectin sequesters essential trace metals from microbes, which inhibits growth. This review focuses on defensins and calprotectin as AMPs that appear to work cooperatively to fortify the epithelial barrier against infection. The antimicrobial spectrum is broad with overlap between the two AMPs. In mice, experimental models highlight the contribution of both AMPs to candidiasis as a fungal infection and periodontitis resulting from bacterial dysbiosis. These AMPs appear to contribute to innate immunity in humans, protecting the commensal microflora and restricting the emergence of pathobionts and pathogens. A striking example in human innate immunity is that elevated serum calprotectin protects against neonatal sepsis. Calprotectin is also remarkable because of functional differences when localized in epithelial and neutrophil cytoplasm or released into the extracellular environment. In the cytoplasm, calprotectin appears to protect against invasive pathogens. Extracellularly, calprotectin can engage pathogen-recognition receptors to activate innate immune and proinflammatory mechanisms. In inflamed epithelial and other tissue spaces, calprotectin, DNA, and histones are released from degranulated neutrophils to form insoluble antimicrobial barriers termed neutrophil extracellular traps. Hence, calprotectin and other AMPs use several strategies to provide microbial control and stimulate innate immunity.

Effect of add-on hydroxychloroquine therapy on serum proinflammatory cytokine levels in patients with systemic lupus erythematosus

We investigated the effect of hydroxychloroquine (HCQ) as an add-on treatment to immunosuppressants on the expression of proinflammatory cytokines in patients with systemic lupus erythematosus. Serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-6, IL-8, vascular endothelial growth factor (VEGF)-A, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), and interleukin 1 receptor antagonist (IL-1ra) were measured immediately before and 3 months after treatment with oral HCQ. Among the 51 patients enrolled in the study, HCQ treatment led to significantly reduced serum levels of TNF-α, IL-6, IL-8, VEGF-A, IL-1ra, and IL-2 (p < 0.0001; p = 0.0006; p = 0.0460, p = 0.0177; p < 0.0001; p = 0.0282, respectively) and to decreased (but not significantly) levels of MIP-1α (p = 0.0746). No significant changes were observed in the serum MCP-1 levels before and after HCQ administration (p = 0.1402). Our results suggest that an add-on HCQ treatment modulates the expression of proinflammatory cytokines even in systemic lupus erythematosus patients with low disease activity.

Anti-inflammatory effects of differential molecular weight Hyaluronic acids on UVB-induced calprotectin-mediated keratinocyte inflammation

BACKGROUND

The biological functions of Hyaluronic acid are related to its molecular weight and binding to its receptor, Toll-like receptor4 (TLR4) or CD44. Recent studies have shown that low-molecular-weight Hyaluronic acid (LMW-HA) exhibits proinflammatory effects, while high-molecular-weight Hyaluronic acid (HMW-HA) functions as an anti-inflammatory factor. UVB-induced epidermal inflammation is mainly mediated by endogenous molecules, such as damage-associated molecular patterns (DAMPs), that cause severe skin damage by activating TLR signaling pathways.

OBJECTIVE

Since both LMW- and HMW-HA have inhibitory functions on TLR-mediated macrophage inflammation, HA is assumed to suppress UVB-induced DAMP-mediated inflammation in the skin. In this study, both Ultra- low-molecular-weight Hyaluronic acid (uLMW-HA) and HMW-HA were found to inhibit UVB-induced keratinocyte inflammation.

METHODS

HaCaT cells were treated with medium containing Hyaluronic acid at the appropriate concentration after 15 mJ/cm² irradiation. Secreted protein levels were determined with ELISA kits. Expression levels of proteins downstream of TLR4 were detected by Simple Western system.

RESULTS

By competitively binding to TLR4, uLMW-HA downregulated Calprotectin-induced TRAF6 expression, which might be the direct process by which uLMW-HA decreased UVB-induced IL-6 secretion. Reduced　CD44 variant (CD44v) expression in keratinocytes attenuated the inhibitory effect of both uLMW-HA and HMW-HA on UVB-induced inflammation, which indicated the involvement of CD44v in HA-regulated anti-inflammatory activity.

CONCLUSION

Overall, this research indicates that Hyaluronic acid is more than a moisturizer; it is also a biologically effective material that can prevent the excessive skin inflammation caused in daily life, especially in the late stages after sunburn.

Comparison of salivary calprotectin levels in periodontitis associated with diabetes mellitus after low-level laser therapy as an adjunct to scaling and root planing: A randomized clinical trial

Context and Aims:

Calprotectin is a myeloid protein, exerting pro-inflammatory effects on various cells and are shown to be elevated in inflammatory diseases. Periodontal therapy has been shown to decrease the levels of calprotectin in body fluids. Hence, the present study was aimed at assessing salivary calprotectin levels in periodontitis associated with diabetes mellitus after low-level laser therapy (LLLT) as an adjunct to scaling and root planing (SRP).

Materials and Methods:

Sixty-four participants were divided into Groups A (periodontitis) and B (periodontitis associated with type 2 diabetes mellitus [T2DM]) based on probing depth of ≥5 mm, clinical attachment level (CAL) of >2 mm, and history of T2DM. Based on assigned treatments, the groups were subdivided into A1, A2, B1, and B2 where A1 and B1 were subjected to SRP alone and A2 and B2 received LLLT as an adjunct to SRP, respectively. The parameters assessed included probing pocket depth, CAL, bleeding on probing (BOP), plaque index (PI), and salivary calprotectin. All the values were subjected for comparison at baseline and 8 weeks.

Statistical Analysis Used:

Multiple group comparisons were done using analysis of variance; intragroup comparisons were made using t-test. The level of significance was assessed at P < 0.05 for all tests.

Results:

All parameters showed a significant difference within the groups from baseline to 8 weeks. Intergroup comparison of PI, BOP, and salivary calprotectin showed a significant difference (P < 0.05).

Conclusions:

Reduction in calprotectin levels was noticed with LLLT when used as an adjunct to SRP. Calprotectin may be used as a prognostic marker for periodontitis.

RASSF1A and p16 promoter methylation and treatment response in chronic hepatitis C genotype 1b patients treated with pegylated interferon/ribavirin

Prevention of chronic hepatitis C (CHC) and its complications is based on antiviral therapy and early detection of reliable molecular markers in persons under risk. We investigated whether the methylation status of RASSF1A and p16 genes, alone or in combination with host and viral factors, affects the response to therapy with pegylated interferon/ribavirin (PEGIFN/ RBV). Methylation-specific polymerase chain reaction (MSP) was used to determine the methylation status of the target promoter sequences of RASSF1A and p16 in circulating-free DNA from the peripheral blood of 49 patients with CHC genotype 1b. The methylation status of the examined genes did not affect the response to therapy. However, the simultaneous presence of either RASSF1A or p16 methylation and the CC genotype of IL28B was significantly related to a sustained virologic response (P=0.009 and P=0.032, respectively). After Bonferroni correction, only the result concerning the RASSF1A gene remained significant (P<0.0125). Methylation of RASSF1A was associated with the CC genotype of the IL28B gene (P=0.024) and a higher viral load (?400 000 IU/mL, P=0.009). Our results suggest that combined analysis of RASSF1A gene methylation and IL28B rs12979860 polymorphism could potentially help in the prediction of therapy response in CHC genotype 1b patients.

Activation of GATA-binding protein 4 regulates monocyte chemoattractant protein-1 and chemotaxis in periodontal ligament cells

BACKGROUND AND OBJECTIVES

Periodontitis is a chronic inflammatory disease of periodontal supporting tissues. The persistent inflammatory reaction depends on the release of chemokines to continuously recruit inflammation cells. GATA-binding protein 4 (GATA4) exerts effects on senescence and inflammation, while its role in periodontitis is far from clear. The present study aims to address the effect of GATA4 on regulating chemokines and the chemotaxis in periodontitis.

MATERIAL AND METHODS

Periodontitis rat models were constructed to detect the expression of GATA4 and the chemokine monocyte chemoattractant protein-1 (MCP-1) by immunohistochemistry. Lipopolysaccharide (LPS)-stimulated human periodontal ligament (PDL) cells and GATA4-knockdown by siRNA transient transfection PDL cells were used to explore the correlation between GATA4 and chemokines. Transwell assay was performed to detect the role of GATA4 for the recruitment effect of chemokines on macrophages. Mitogen-activated protein kinase (MAPK) inhibitors were scheduled to intervene in LPS-stimulated PDL cells to examine the association between MAPK signaling pathways and GATA4. The expression of GATA4, chemokines, or MAPK signaling molecules was determined by quantitative real-time polymerase chain reaction, western blotting, or cell immunofluorescence.

RESULTS

The expression of GATA4 and MCP-1 was significantly increased in periodontitis rat models and in LPS-stimulated PDL cells. Knockdown GATA4 inhibited the expression of GATA4 and MCP-1 as well as suppressed the recruitment of macrophage in LPS-stimulated PDL cells. Inhibitors of p38 and ERK1/2 signaling pathways significantly downregulated the increased expression of GATA4 and MCP-1 induced by LPS in PDL cells.

CONCLUSIONS

GATA-binding protein 4 could act as an upstream regulator of MCP-1 and as a downstream regulator of p38 and ERK1/2 signaling pathways to initiate inflammation response and regulate chemotaxis during the progression of periodontitis.

Appendiceal inflammation in colectomy is independently correlated with early pouchitis following ileal pouch anal anastomosis in ulcerative colitis and indeterminate colitis

BACKGROUND

Appendiceal inflammation in colectomy is one of the histologic predictors of pouchitis in ulcerative colitis (UC) following ileal pouch anal anastomosis (IPAA). Fecal calprotectin level has been shown to increase 2 months prior to the onset of pouchitis. We evaluated whether inflammation and calprotectin expression in appendiceal specimens correlate with early-onset pouchitis in UC and indeterminate colitis (IC).

MATERIALS AND METHODS

IPAA (2000-2018) cases with appendix blocks available in colectomy specimens were identified (n = 93, 90 UC, 3 IC). Histologic features thought to predict pouchitis were evaluated. The degree of appendiceal inflammation was scored. Calprotectin immunostain was performed on the appendix blocks and the extent of mucosal staining was quantified. Electronic medical records were reviewed for demographics, smoking history, clinical pouchitis, time of onset of pouchitis, and clinical and endoscopic components of the Pouchitis Disease Activity Index (PDAI) score. Follow-up pouch biopsies were reviewed and scored to generate histologic PDAI score, when available.

RESULTS

Among the patients with clinical pouchitis (n = 73), moderate to severe appendiceal inflammation independently correlated with earlier pouchitis compared to no/mild inflammation (median time to pouchitis 12.0 vs. 23.8, log rank p = 0.016). Calprotectin staining correlated with inflammatory scores of the appendix (Spearman's rho, r = 0.630, p < 0.001) but not with early pouchitis (p > 0.05).

CONCLUSIONS

The presence of moderate to severe appendiceal inflammation at the time of colectomy was associated with a shorter time to pouchitis following IPAA. Calprotectin immunostain may be used to demonstrate the presence of inflammation in the appendix but its role in predicting early pouchitis remains limited.

Estrogen Receptor β as a Candidate Regulator of Sex Differences in the Maternal Immune Activation Model of ASD

Interestingly, more males are diagnosed with autism spectrum disorder (ASD) than females, yet the mechanism behind this difference is unclear. Genes on the sex chromosomes and differential regulation by sex steroid hormones and their receptors are both candidate mechanisms to explain this sex-dependent phenotype. Nuclear receptors (NRs) are a large family of transcription factors, including sex hormone receptors, that mediate ligand-dependent transcription and may play key roles in sex-specific regulation of immunity and brain development. Infection during pregnancy is known to increase the probability of developing ASD in humans, and a mouse model of maternal immune activation (MIA), which is induced by injecting innate immune stimulants into pregnant wild-type mice, is commonly used to study ASD. Since this model successfully recaptures the behavioral phenotypes and male bias observed in ASD, we will discuss the potential role of sex steroid hormones and their receptors, especially focusing on estrogen receptor (ER)β, in MIA and how this signaling may modulate transcription and subsequent inflammation in myeloid-lineage cells to contribute to the etiology of this neurodevelopmental disorder.

Fisetin attenuates periodontitis through FGFR1/TLR4/NLRP3 inflammasome pathway

The purpose of the present study was to investigate the pharmacological effect of Fisetin on experimental periodontitis in rats and explore its potential mechanism. The ligature/LPS method was used to induce periodontitis in rats. LPS was employed to cause inflammation in Human gingival fibroblasts (HGF). The transfections with FGFR1 SiRNA, NLRP3 SiRNA and the selective TLR4 inhibitor TAK242 were used to investigate the mechanism of Fisetin-mediated inflammatory reaction in LPS-induced HGF. As a result, Fisetin reduced the alveolar bone gap, reversed histopathological lesion and inhibited serum inflammatory cytokine concentration in periodontitis rats. Fisetin decreased the inflammatory cytokine contents in the supernatant of LPS-induced HGF. The inhibitory effect of Fisetin might be attributed to FGFR1/TLR4/NLRP3 inflammasome pathway both in vivo and in vitro. The suppressions of FGFR1, TLR4 and NLRP3 proved that FGFR1/TLR4/NLRP3 signaling was involved in the Fisetin-mediated inflammatory response. Fisetin also inhibited NLRP3 priming. The data demonstrated that Fisetin attenuated periodontitis by inhibiting inflammatory reaction via FGFR1/TLR4/NLRP3 inflammasome pathway.

Impact of Exercise Intensity on Calprotectin Levels in Healthy Volunteers and Patients with Inflammatory Rheumatic Diseases

Exercise influences inflammatory response and immune system performance. The regular practice of a moderate activity positively regulates immunity and the inflammatory process, while intensive training depresses it and enhances inflammatory marker secretion. Calprotectin is involved in the inflammatory process, promoting neutrophil recruitment, cell degranulation, and inflammatory mediators. Furthermore, calprotectin has been associated with various inflammatory diseases, including inflammatory rheumatic diseases. The present review explores the effect of exercise on calprotectin levels in both healthy and inflammatory rheumatic conditions. Data show that the intensity duration and the type of exercise modulate calprotectin levels and participant inflammatory status. The exact role of calprotectin in the exercise response is yet unknown. Calprotectin could constitute an interesting biomarker for monitoring both the effect of exercise on the inflammatory process in healthy volunteers and the efficiency of exercise treatment programs in a patient with inflammatory rheumatic disease.

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.

Emerging roles of neutrophil-borne S100A8/A9 in cardiovascular inflammation

Elevated neutrophil count is associated with higher risk of major adverse cardiac events including myocardial infarction and early development of heart failure. Neutrophils contribute to cardiac damage through a number of mechanisms, including attraction of other immune cells and release of inflammatory mediators. Recently, a number of independent studies have reported a causal role for neutrophil-derived alarmins (i.e. S100A8/A9) in inducing inflammation and cardiac injury following myocardial infarction (MI). Furthermore, a positive correlation between serum S100A8/A9 levels and major adverse cardiac events (MACE) in MI patients was also observed implying that targeting neutrophils or their inflammatory cargo could be beneficial in reducing heart failure. However, contradictory to this idea, neutrophils and neutrophil-derived S100A8/A9 also seem to play a vital role in the resolution of inflammation. Thus, a better understanding of how neutrophils balance these seemingly contrasting functions would allow us to develop effective therapies that preserve the inflammation-resolving function while restricting the damage caused by inflammation. In this review, we specifically discuss the mechanisms behind neutrophil-derived S100A8/A9 in promoting inflammation and resolution in the context of MI. We also provide a perspective on how neutrophils could be potentially targeted to ameliorate cardiac inflammation and the ensuing damage.

Neutrophil calprotectin identifies severe pulmonary disease in COVID-19

Severe cases of coronavirus disease 2019 (COVID-19) are regularly complicated by respiratory failure. Although it has been suggested that elevated levels of blood neutrophils associate with worsening oxygenation in COVID-19, it is unknown whether neutrophils are drivers of the thrombo-inflammatory storm or simple bystanders. To better understand the potential role of neutrophils in COVID-19, we measured levels of the neutrophil activation marker S100A8/A9 (calprotectin) in hospitalized patients and determined its relationship to severity of illness and respiratory status. Patients with COVID-19 (n = 172) had markedly elevated levels of calprotectin in their blood. Calprotectin tracked with other acute phase reactants including C-reactive protein, ferritin, lactate dehydrogenase, and absolute neutrophil count, but was superior in identifying patients requiring mechanical ventilation. In longitudinal samples, calprotectin rose as oxygenation worsened. When tested on day 1 or 2 of hospitalization (n = 94 patients), calprotectin levels were significantly higher in patients who progressed to severe COVID-19 requiring mechanical ventilation (8039 ± 7031 ng/ml, n = 32) as compared to those who remained free of intubation (3365 ± 3146, P < 0.0001). In summary, serum calprotectin levels track closely with current and future COVID-19 severity, implicating neutrophils as potential perpetuators of inflammation and respiratory compromise in COVID-19.

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.

Neutrophil calprotectin identifies severe pulmonary disease in COVID-19

Severe cases of coronavirus disease 2019 (COVID-19) are regularly complicated by respiratory failure. While it has been suggested that elevated levels of blood neutrophils associate with worsening oxygenation in COVID-19, it is unknown whether neutrophils are drivers of the thrombo-inflammatory storm or simple bystanders. To better understand the potential role of neutrophils in COVID-19, we measured levels of the neutrophil activation marker S100A8/A9 (calprotectin) in hospitalized patients and determined its relationship to severity of illness and respiratory status. Patients with COVID-19 (n=172) had markedly elevated levels of calprotectin in their blood. Calprotectin tracked with other acute phase reactants including C-reactive protein, ferritin, lactate dehydrogenase, and absolute neutrophil count, but was superior in identifying patients requiring mechanical ventilation. In longitudinal samples, calprotectin rose as oxygenation worsened. When tested on day 1 or 2 of hospitalization (n=94 patients), calprotectin levels were significantly higher in patients who progressed to severe COVID-19 requiring mechanical ventilation (8039 +/- 7031 ng/ml, n=32) as compared to those who remained free of intubation (3365 +/- 3146, p<0.0001). In summary, serum calprotectin levels track closely with current and future COVID-19 severity, implicating neutrophils as potential perpetuators of inflammation and respiratory compromise in COVID-19.

Quantitative proteomic characterization of microvesicles/exosomes from the cerebrospinal fluid of patients with acute bilirubin encephalopathy

Severe hyperbilirubinemia causes neurotoxicity and may lead to acute bilirubin encephalopathy (ABE) during the critical period of central nervous system development. The aim of the present study was to identify differentially expressed proteins (DEPs) in microvesicles/exosomes (MV/E) isolated from the cerebrospinal fluid (CSF) of patients with ABE. Co-precipitation was used to isolate the MV/E from the CSF of patients with ABE and age-matched controls. Isobaric tagging for relative and absolute quantification-based proteomic technology combined with liquid chromatography/tandem mass spectrometry was used to identify DEPs in the MV/E. Bioinformatics analysis was subsequently performed to investigate Gene Ontology functional annotation and Kyoto Encyclopedia of Genes and Genomes enriched signaling pathways of these DEPs. A total of four proteins were selected for further validation via western blotting. A total of 291 dysregulated proteins were identified by comparing the patients with ABE with the controls. Bioinformatics analysis indicated the involvement of immune-inflammation-associated cellular processes and signaling pathways in the pathophysiology of ABE. In conclusion, the present study identified the proteomic profile of MV/E isolated from the CSF of patients with ABE. These results may provide an improved understanding of the pathogenesis of ABE and may help to identify early diagnostic biomarkers and therapeutic targets.

PE_PGRS31-S100A9 Interaction Promotes Mycobacterial Survival in Macrophages Through the Regulation of NF-κB-TNF-α Signaling and Arachidonic Acid Metabolism

Mycobacterium tuberculosis (M. tb) evades the surveillance of immune responses for survival in macrophages. However, the precise mechanism and toxins/proteins encoded by M. tb involved in the bacterial escape remain elusive. The function of Rv1768 protein (also referred to as PE_PGRS31, belonging to the PE_PGRS family) encoded by the region of deletion 14 (RD-14) in the virulent M. tb H37Rv strain has not, to the best of our knowledge, been reported previously. Here, we found that Rv1768 remarkably promotes bacterial survival in macrophages. Compared to wild type (WT) H37Rv, the Rv1768 deficient strain (H37RvΔ1768) showed significantly decreased colony-forming units in the lungs, spleen, and liver of the murine M. tb infection model. The bacterial burdens of WT H37Rv in WT macrophages and C57BL/6 mice were significantly higher than those in S100A9 deficiency cells and mice, but there were no significant differences for H37RvΔRv1768. Rv1768 binds S100A9 with the proline-glutamic acid domain (PE domain) and blocks the interaction between S100A9 and Toll-like receptor 4 (TLR4), and suppresses TLR4-myeloid differentiation factor 88-nuclear factor-kappa B (NF-κB)-tumor necrosis factor α (TNF-α) signaling in macrophages. Interestingly, Rv1768 binding to S100A9 also disturbs the metabolism of arachidonic acid by activating 5-lipoxygenase, increasing lipotoxin A4, and down-regulating cyclooxygenase-2 and prostaglandin E2 expression, thus, promoting mycobacterial survival. Our results revealed that M. tb Rv1768 promotes mycobacterial survival in macrophages by regulating NF-κB-TNF-α signaling and arachidonic acid metabolism via S100A9. Disturbing the interaction between Rv1768 and S100A9 may be a potential therapeutic target for tuberculosis.

The predictive role of serum calprotectin on mortality in hemodialysis patients with high phosphoremia

Background

The inflammatory mediator calprotectin (CPT, myeloid-related protein 8/14) is known as an endogenous ligand contributing to pathophysiology in inflammatory diseases. Serum CPT reportedly became a potential biomarker in these conditions, though there is no report predicting the prognosis in hemodialysis patients. The aim of this study is to investigate the predictive role of serum CPT on mortality in hemodialysis patients.

Methods

We conducted a multicenter, observational cohort study of 388 Japanese subjects undergoing hemodialysis. Serum CPT were measured using an ELISA. The potential associations between serum CPT and clinical variables were cross-sectionally examined. Multivariate Cox regression was used to estimate the association between serum CPT, high-sensitivity C reactive protein (hs-CRP), white blood cell (WBC) count and mortality. Median follow-up was 6.6 years.

Results

The median CPT level was 6108 ng/ml (median in healthy subjects, 2800) at baseline. Serum CPT positively correlated with WBC count (ρ = 0.54, P < 0.001) and hs-CRP values (ρ = 0.35, P < 0.001). In multivariate analysis, hs-CRP was an independent predictor of all-cause mortality after adjusting confounding factors (middle vs. low: hazard ratio [HR] 2.09, 95% confidence interval [CI] 1.23–3.66; high vs. low: 2.47, 1.40–4.47). In the analysis by stratum of phosphate levels, elevated CPT levels were significantly associated with all-cause mortality in the highest tertile (18.1; 3.15–345.9) among the high-phosphate group, but not among the low-phosphate group.

Conclusions

Serum CPT would become a potential predictive marker on mortality in hemodialysis patients with high-phosphate levels.

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.

S100 family proteins in inflammation and beyond

The S100 family proteins possess a variety of intracellular and extracellular functions. They interact with multiple receptors and signal transducers to regulate pathways that govern inflammation, cell differentiation, proliferation, energy metabolism, apoptosis, calcium homeostasis, cell cytoskeleton and microbial resistance. S100 proteins are also emerging as novel diagnostic markers for identifying and monitoring various diseases. Strategies aimed at targeting S100-mediated signaling pathways hold a great potential in developing novel therapeutics for multiple diseases. In this chapter, we aim to summarize the current knowledge about the role of S100 family proteins in health and disease with a major focus on their role in inflammatory conditions.

Extracellular Trap-Mimicking DNA-Histone Mesostructures Synergistically Activate Dendritic Cells

Extracellular traps (ETs), such as neutrophil extracellular traps, are a physical mesh deployed by immune cells to entrap and constrain pathogens. ETs are immunogenic structures composed of DNA, histones, and an array of variable protein and peptide components. While much attention has been paid to the multifaceted function of these structures, mechanistic studies of ETs remain challenging due to their heterogeneity and complexity. Here, a novel DNA-histone mesostructure (DHM) formed by complexation of DNA and histones into a fibrous mesh is reported. DHMs mirror the DNA-histone structural frame of ETs and offer a facile platform for cell culture studies. It is shown that DHMs are potent activators of dendritic cells and identify both the methylation state of DHMs and physical interaction between dendritic cells and DHMs as key tuning switches for immune stimulation. Overall, the DHM platform provides a new opportunity to study the role of ETs in immune activation and pathophysiology.

Time-Course Transcriptome Analysis for Drug Repositioning in Fusobacterium nucleatum-Infected Human Gingival Fibroblasts

Fusobacterium nucleatum (F. nucleatum) is a crucial periodontal pathogen and human gingival fibroblasts (GFs) are the first line of defense against oral pathogens. However, the research on potential molecular mechanisms of host defense and effective treatment of F. nucleatum infection in GFs remains scarce. In this study, we undertook a time-series experiment and performed an RNA-seq analysis to explore gene expression profiles during the process of F. nucleatum infection in GFs. Differentially expressed genes (DEGs) could be divided into three coexpression clusters. Functional analysis revealed that the immune-related signaling pathways were more overrepresented at the early stage, while metabolic pathways were mainly enriched at the late stage. We computationally identified several U.S. Food and Drug Administration (FDA)-approved drugs that could protect the F. nucleatum infected GFs via a coexpression-based drug repositioning approach. Biologically, we confirmed that six drugs (etravirine, zalcitabine, wortmannin, calcium D-pantothenate, ellipticine, and tanespimycin) could significantly decrease F. nucleatum-induced reactive oxygen species (ROS) generation and block the Protein Kinase B (PKB/AKT)/mitogen-activated protein kinase signaling pathways. Our study provides more detailed molecular mechanisms of the process by which F. nucleatum infects GFs and illustrates the value of the cogena-based drug repositioning method and the potential therapeutic application of these tested drugs in the treatment of F. nucleatum infection.

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.

The molecular mechanisms driving physiological changes after long duration space flights revealed by quantitative analysis of human blood proteins

BACKGROUND

The conditions of space flight have a significant effect on the physiological processes in the human body, yet the molecular mechanisms driving physiological changes remain unknown.

METHODS

Blood samples of 18 Russian cosmonauts who had conducted long-duration missions to the International Space Station were collected 30 days before launch and on the first and seventh days after landing.

RESULTS

A panel of 125 proteins in the blood plasma was quantitated by a well-established and highly regarded targeted mass spectrometry approach. This method involves the monitoring of multiple reactions in conjunction with stable isotope-labeled standards at the University of Victoria - Genome BC Proteomics Centre.

CONCLUSIONS

Reduction of circulating plasma volume during space flight and activation of fluid retention at the final stage of the flight affect the changes in plasma protein concentrations present in the first days after landing. Using an ANOVA approach, it was revealed that only 1 protein (S100A9) reliably responded to space flight conditions. This protein plays an important role in the functioning of the endothelium and can serve as a marker for activation of inflammatory reactions. Concentrations of the proteins of complement, coagulation cascades, and acute phase reactants increase in the blood of cosmonauts as measured the first day after landing. Most of these proteins' concentrations continue to increase by the 7th day after space flight. Similar dynamics are observed for proteases and their inhibitors. Thus, there is a shift in proteolytic blood systems, which is necessary for the restoration of muscle tissue and maintenance of oncotic homeostasis.

Understanding the pathophysiology behind chairside diagnostics and genetic testing for IL-1 and IL-6

In order for chairside diagnostic testing to make an impact on dental therapy, practitioners require a better understanding of genetic mutations contributing to the pathophysiology of periodontal disease. Commensal and pathogenic bacterial colonization in oral cavity tissues produces a cascade of proinflammatory signaling pathways ultimately detrimental to host tissues. Resolving inflammation is a multifactorial process involving the downregulation of proinflammatory cytokines while allowing commensal bacterial levels to return to normal. Because of the complicated nature of commensal bacteria and oral health homeostasis, the emphasis of dental therapy should place renewed focus on limiting destructive inflammation rather than solely eliminating bacteria. Salivary diagnostics are an easy, non-invasive way to assess inflammatory markers. Inflammatory cytokine levels can help determine the subclinical health of a patient, showing the transition from health to gingivitis, or periodontitis, prior to clinical presentation. Single nucleotide polymorphism mutations can aid in determining increased risk of developing periodontitis. Taken together, and alongside regular clinical evaluations, chairside diagnostics help individualize treatment plans to slow, or halt, the progression of disease-before tissue destruction can take place. While more studies are needed analyzing specific mutations across periodontal categories, chairside diagnostics present an exciting adjunct to improve patient care.

Salivary S100 proteins screen periodontitis among Korean adults

AIM

This study aims to evaluate the association of salivary S100A8 and A9 proteins with periodontitis and its screening ability for periodontitis cross-sectionally.

MATERIAL AND METHODS

We selected 326 participants from the Yangpyeong Cohort: 218 participants with periodontitis and 108 participants without periodontitis. Stage II-IV periodontitis according to the modification of new international classification of periodontitis was considered as periodontitis. S100A8 and A9 were assayed using enzyme-linked immunosorbent assay kit. Age, sex, education, smoking, drinking, exercise, and metabolic syndrome were factored as confounders. Analyses of covariance and logistic regression analysis were applied to evaluate the association of S100A8 and A9 with periodontitis. Receiver operating characteristic curve was applied for screening ability.

RESULTS

Those with periodontitis compared to those without periodontitis showed higher adjusted amount of S100A8 (3694 versus 6757 ng/ml, p < 0.001), but less adjusted amount of S100A9 (1341 versus 1030 ng/ml, p = 0.015). The screening ability of S100A8 and A9 on periodontitis was c-statistics of 0.69 (p < 0.001) for both S100A8 and A9, 0.67 for S100A8 and 0.63 (p < 0.001) for S100A9.

CONCLUSIONS

Overall, salivary S100A8 and S100A9 could be practical markers for periodontitis. Its screening ability for periodontitis could be beneficial in clinics and at home.

Loss of the adhesion G-protein coupled receptor ADGRF5 in mice induces airway inflammation and the expression of CCL2 in lung endothelial cells

Background

Adhesion G-protein coupled receptor F5 (ADGRF5) was recently identified as an essential regulator of pulmonary surfactant homeostasis in alveolar type II cells. We previously showed that in addition to abnormal surfactant accumulation, Adgrf5-deficient (Adgrf5^−/−) mice exhibit emphysema-like signs, suggesting a possible role for ADGRF5 in immune regulation. Here, we extended the phenotypic analysis of Adgrf5^−/− mice to help understand its biological role in the lung, and especially in immune regulation.

Methods

Histological features of lungs were evaluated by Alcian blue and Masson’s trichrome staining. Quantitative real-time PCR (qPCR) and western blot analyses were performed to analyze the differential expression of genes/proteins related to airway inflammation in lungs between wildtype and Adgrf5^−/− mice. Acid–base status was assessed by performing blood gas tests and urine pH measurements. Inflammatory cell counting was performed using Giemsa-stained bronchoalveolar lavage cells. Serum IgE concentrations were determined by enzyme-linked immunosorbent assay. The expression of Ccl2, S100a8, S100a9, and Saa3 in primary lung endothelial cells (ECs) was determined by qPCR and/or western blotting. Finally, the effect of administrating RS504393 to 2-week-old Adgrf5^−/− mice on gene expression in the lungs was analyzed by qPCR.

Results

Adgrf5^−/− mice exhibited several features of chronic airway inflammation (mucous cell metaplasia, mucus hyperproduction, subepithelial fibrosis, respiratory acidosis, high serum IgE, mast cell accumulation, and neutrophilia) in parallel with elevated expression of genes involved in mucous cell metaplasia (Muc5ac, Muc5b, Slc26a4, and Clca1), fibrosis (Tgfb1, Col1a1, Fn1, and Tnc), and type 2 immune response (Il4, Il5, Il13, IL-25, and IL-33) at 12 and/or 30 weeks of age. In contrast, mRNA expression of Ccl2, S100a8, and S100a9 was upregulated in embryonic or neonatal Adgrf5^−/− lungs as well as in lung ECs of Adgrf5^−/− mice at 1 week of age. RS504393 treatment suppressed the upregulation of S100a8, S100a9, Slc26a4, and Il5 in Adgrf5^−/− lungs.

Conclusions

Targeted disruption of ADGRF5 results in the development of airway inflammation, which is likely mediated by the type 2 immune response and possibly CCL2-mediated inflammation. ADGRF5 also has a potential role in the regulation of genes encoding CCL2 in lung ECs, thereby maintaining immune homeostasis.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-0973-6) contains supplementary material, which is available to authorized users.

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.