Interleukin 33 supports squamous cell carcinoma growth via a dual effect on tumour proliferation, migration and invasion, and T cell activation

Interleukin (IL)-33 is an important cytokine in the tumour microenvironment; it is known to promote the growth and metastasis of solid cancers, such as gastric, colorectal, ovarian and breast cancer. Our group demonstrated that the IL-33/ST2 pathway enhances the development of squamous cell carcinoma (SCC). Conversely, other researchers have reported that IL-33 inhibits tumour progression. In addition, the crosstalk between IL-33, cancer cells and immune cells in SCC remains unknown. The aim of this study was to investigate the effect of IL-33 on the biology of head and neck SCC lines and to evaluate the impact of IL-33 neutralisation on the T cell response in a preclinical model of SCC. First, we identified epithelial and peritumoural cells as a major local source of IL-33 in human SCC samples. Next, in vitro experiments demonstrated that the addition of IL-33 significantly increased the proliferative index, motility and invasiveness of SCC-25 cells, and downregulated MYC gene expression in SCC cell lines. Finally, IL-33 blockade significantly delayed SCC growth and led to a marked decrease in the severity of skin lesions. Importantly, anti-IL-33 monoclonal antibody therapy increase the percentage of CD4+IFNγ+ T cells and decreased CD4+ and CD8+ T cells secreting IL-4 in tumour-draining lymph nodes. Together, these data suggest that the IL-33/ST2 pathway may be involved in the crosstalk between the tumour and immune cells by modulating the phenotype of head and neck SCC and T cell activity. IL-33 neutralisation may offer a novel therapeutic strategy for SCC.

Fcγ receptors on aging neutrophils

OBJECTIVE

Neutrophils are key effector cells of the innate immune system. They recognize antigens through membrane receptors, which are expressed during their maturation and activation. Neutrophils express FcγRII (CD32), FcγRIII (CD16), and FcγRI (CD64) after being activated by different factors such as cytokines and bacterial products. These receptors are involved with phagocytosis of IgG-opsonized microbes and enhance defense mechanisms. Based on that, our study seeks to compare the expression of FcγRII, FcγRIII, FcγRI, and CD11b on neutrophils from elderly and young subjects and their expression after in vitro activation with cytokines and LPS.

METHODOLOGY

Neutrophils were isolated from human peripheral blood and from mice bone marrow by density gradient. After isolation, FCγRs expression was immediately analyzed by flow cytometry or after in vitro stimulation.

RESULTS

In freshly isolated cells, the percentage of FcγRIIIb+ and CD11b+ neutrophils were higher in samples from young individuals; FcγRIIIa expression was more prominent on aged neutrophils; FcγRIA expression was similar in all samples analyzed. Exposure to CXCL8 and LPS resulted in a higher percentage of FcγRIa+ neutrophils on elderly individuals' samples but lower when compared with neutrophils from young donors. We observed that LPS caused an increase in FcγRIIa expression on aging human neutrophils. In contrast, FcγRIIIb expression in response to CXCL8 and LPS stimulation was not altered in the four groups. CD11b expression was lower in neutrophils from elderly individuals even in response to LPS and CXCL8. In mice, we observed differences only regarding CD11b expression, which was increased on aged neutrophils. LPS exposure caused an increase in all FcγRs.

CONCLUSIONS

Our results suggest that, in humans, the overall pattern of FcγR expression and integrin CD11b are altered during aging and immunosenescence might contribute to age-related infection.

Increased serum levels of interleukin-6 in erythema nodosum leprosum suggest its use as a biomarker

BACKGROUND

Erythema nodosum leprosum (ENL) is a frequent complication of multibacillary leprosy that can result in significant morbidity, including peripheral nerve damage and physical disability. The identification of possible serum markers could be a valuable tool for the early detection of ENL.

AIMS

The purpose of this study was to evaluate selected serum mediators involved in the innate and adaptive immune responses to identify possible immunomarkers for ENL.

METHODS

The levels of interleukin-2, interleukin-4, interleukin-6, interleukin-10, interleukin-17, interferon-γ, tumor necrosis factor, nitric oxide and anti-phenolic glycolipid-I antibodies were measured in the sera of leprosy patients with ENL [at the beginning of reaction (M0) and 1 month later (M1)], and then compared with the levels of the same markers in patients with untreated multibacillary leprosy without ENL (controls with leprosy: CTRL) and healthy individuals (healthy controls: CTRH).

RESULTS

Significantly higher levels of serum interleukin-6 were observed in M0 than in CTRL. In addition, pairwise comparisons showed higher levels of interleukin-6 in M0 compared to M1. Levels of tumor necrosis factor were higher in M0 than in CTRL, with no significant difference between M0 and M1. There were no differences in the levels of interleukin-2, interleukin-4, interleukin-10, interleukin-17 or interferon-γ between groups. The CTRL group had higher levels of nitric oxide compared to M0 and M1. High levels of anti-phenolic glycolipid-I were observed in M0, M1 and CTRL than in CTRH.

LIMITATIONS

Three patients were not assessed at M1, decreasing the number of evaluated patients from 14 to 11.

CONCLUSION

High-serum levels of interleukin-6 were observed during ENL, primarily in patients with more severe reactions; levels decreased after specific therapy, suggesting a role for this cytokine in pathogenesis and its utility as an ENL biomarker. Further studies should explore whether interleukin-6 could also be used as a predictive marker for ENL or as a specific target for its treatment.

The Tumor Microenvironment in SCC: Mechanisms and Therapeutic Opportunities

Squamous cell carcinoma (SCC) is the second most common skin cancer worldwide and, despite the relatively easy visualization of the tumor in the clinic, a sizeable number of SCC patients are diagnosed at advanced stages with local invasion and distant metastatic lesions. In the last decade, immunotherapy has emerged as the fourth pillar in cancer therapy via the targeting of immune checkpoint molecules such as programmed cell-death protein-1 (PD-1), programmed cell death ligand-1 (PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). FDA-approved monoclonal antibodies directed against these immune targets have provide survival benefit in a growing list of cancer types. Currently, there are two immunotherapy drugs available for cutaneous SCC: cemiplimab and pembrolizumab; both monoclonal antibodies (mAb) that block PD-1 thereby promoting T-cell activation and/or function. However, the success rate of these checkpoint inhibitors currently remains around 50%, which means that half of the patients with advanced SCC experience no benefit from this treatment. This review will highlight the mechanisms by which the immune checkpoint molecules regulate the tumor microenvironment (TME), as well as the ongoing clinical trials that are employing single or combinatory therapeutic approaches for SCC immunotherapy. We also discuss the regulation of additional pathways that might promote superior therapeutic efficacy, and consequently provide increased survival for those patients that do not benefit from the current checkpoint inhibitor therapies.

Mast cells exhibit intracellular microbicidal activity against Aggregatibacter actinomycetemcomitans

BACKGROUND AND OBJECTIVE

Several studies have demonstrated that mast cells are equipped with versatile tools to combat and kill bacteria. Additionally, mast cells produce and secrete a variety of mediators, which either regulate the host's immune system or directly attack bacteria. In this study, the intracellular microbicidal capacity of mast cells against Aggregatibacter actinomycetemcomitans was evaluated.

METHODS

Murine mast cells were challenged in vitro with A actinomycetemcomitans for 3, 5, 10, and 24 hours. Subsequently, the colony-forming units were counted. Additionally, the production and release of nitric oxide and hydrogen peroxide were analyzed by DAF-FM diacetate, the Griess reaction, and the Amplex Red kit, respectively. Cell death was evaluated using FITC Annexin V and propidium iodide staining.

RESULTS

Mast cells are able to efficiently eliminate periodontopathogen, with best results after 10 hours of intracellular challenge. The production/release of nitric oxide-and to a lesser extent of hydrogen peroxide-by mast cells was in agreement with its microbicidal capacity. Ninety percent of the mast cells  maintained their cellular viability even after 24 hours of bacterial challenge.

CONCLUSIONS

This is-to the best of our knowledge-the first report to describe the intracellular microbicidal activity of mast cells against A actinomycetemcomitans, concerning the production and release of potentially bactericidal substances. Further, the low number of cell deaths confirms that the decreased number of colony-forming units was due to the higher antimicrobial activity of mast cells. The results highlight the importance of these cells in the defense mechanisms of biofilm-induced periodontal disease.

HGMB1 and RAGE as Essential Components of Ti Osseointegration Process in Mice

The release of the prototypic DAMP High Mobility Group Box 1 (HMGB1) into extracellular environment and its binding to the Receptor for Advanced Glycation End Products (RAGE) has been described to trigger sterile inflammation and regulate healing outcome. However, their role on host response to Ti-based biomaterials and in the subsequent osseointegration remains unexplored. In this study, HMGB1 and RAGE inhibition in the Ti-mediated osseointegration were investigated in C57Bl/6 mice. C57Bl/6 mice received a Ti-device implantation (Ti-screw in the edentulous alveolar crest and a Ti-disc in the subcutaneous tissue) and were evaluated by microscopic (microCT [bone] and histology [bone and subcutaneous]) and molecular methods (ELISA, PCR array) during 3, 7, 14, and 21 days. Mice were divided into 4 groups: Control (no treatment); GZA (IP injection of Glycyrrhizic Acid for HMGB1 inhibition, 4 mg/Kg/day); RAP (IP injection of RAGE Antagonistic Peptide, 4 mg/Kg/day), and vehicle controls (1.5% DMSO solution for GZA and 0.9% saline solution for RAP); treatments were given at all experimental time points, starting 1 day before surgeries. HMGB1 was detected in the Ti-implantation sites, adsorbed to the screws/discs. In Control and vehicle groups, osseointegration was characterized by a slight inflammatory response at early time points, followed by a gradual bone apposition and matrix maturation at late time points. The inhibition of HMGB1 or RAGE impaired the osseointegration, affecting the dynamics of mineralized and organic bone matrix, and resulting in a foreign body reaction, with persistence of macrophages, necrotic bone, and foreign body giant cells until later time points. While Control samples were characterized by a balance between M1 and M2-type response in bone and subcutaneous sites of implantation, and also MSC markers, the inhibition of HMGB1 or RAGE caused a higher expression M1 markers and pro-inflammatory cytokines, as well chemokines and receptors for macrophage migration until later time points. In conclusion, HMGB1 and RAGE have a marked role in the osseointegration, evidenced by their influence on host inflammatory immune response, which includes macrophages migration and M1/M2 response, MSC markers expression, which collectively modulate bone matrix deposition and osseointegration outcome.

TBX21-1993T/C polymorphism association with Th1 and Th17 response at periapex and with periapical lesions development risk

TBX21-1993T/C (rs4794067) polymorphism increases the transcriptional activity of the Tbx21, essential for interferon gamma (IFNg) transcription, but its functional impact on development Th1- response in vivo remains unclear, as well its potential influence over inflammatory osteolytic conditions, such as periapical lesions. Therefore, this study comprises a case-control and functional investigation of Tbx21 genetic variations impact on Th1 response in vivo and in vitro, and its impact on periapical lesions risk and outcome, performed with a population of healthy controls (H; N = 283) and patients presenting periapical lesions (L; N = 188) or deep caries (DC; N = 152). TBX21-1993T/C genotyping demonstrated that the polymorphic allele C, as well TC/TC+CC genotypes, was significantly less frequent in the L patients compared to H and DC groups. Additionally, gene expression analysis demonstrates that T-cell-specific T-box transcription factor (Tbet) and IFNg transcripts levels were downregulated whereas IL-17 levels were upregulated in the TBX21-1993 C carriers (TC/TC+CC) in comparison with the TT group. Also, while TT and TC+CC genotypes are equally prevalent in the lesions presenting low IFN/IL17 ratio, a significant decrease in polymorphic TC+CC genotypes was observed in lesions presenting intermediate and high IFN/IL17 ratio. In vitro experiments confirmed the predisposition to Th1 polarization associated with TBX21-1993, since PBMC CD4 T cells from T allele carriers produce higher IFNg levels upon CD3/CD28 stimulation than the C group, in both standard/neutral and Th1-polarizing culture conditions. In conclusion, the TBX21-1993 T allele and TC/CC genotypes predispose to Th1-type immune response development in vitro, influence immune response polarization in vivo, and consequently account for the risk for apical periodontitis development.

ST2/IL-33 signaling promotes malignant development of experimental squamous cell carcinoma by decreasing NK cells cytotoxicity and modulating the intratumoral cell infiltrate

Squamous cell carcinoma (SCC) is the second most common form of skin cancer and the mechanism(s) involved in the progression of this tumor are unknown. Increases in the expression of IL-33/ST2 axis components have been demonstrated to contribute to neoplastic transformation in several tumor models and interleukin-33 is correlated with poor prognosis of patients with squamous cell carcinoma of the tongue. Based on these observations, we sought to determine the role of the IL-33/ST2 pathway during the development of SCC. Our findings show that ST2-deficiency led to a marked decrease in the severity of skin lesions, suggesting that ST2 signaling contributed to tumor development. An analysis of tumor lesions in wild-type and ST2KO mice revealed that a lack of ST2 was associated with specific and significant reductions in the numbers of CD4⁺ T cells, CD8⁺ T cells, dendritic cells, and macrophages. In addition, NK cells that were isolated from ST2KO mice exhibited higher cytotoxic activity than cells isolated from wild-type mice. Notably, ST2 deficiency resulted in lower IFN-γ, TNF-α, IL-10, and IL-17 production in tumor samples. Our findings indicate that the IL-33/ST2 pathway contributes to the development of SCC by affecting leukocyte migration to tumor microenvironment and impairing NK cytotoxic activity.

Immune Checkpoints in Leprosy: Immunotherapy As a Feasible Approach to Control Disease Progression

Leprosy remains a health problem in several countries. Current management of patients with leprosy is complex and requires multidrug therapy. Nonetheless, antibiotic treatment is insufficient to prevent nerve disabilities and control Mycobacterium leprae. Successful infectious disease treatment demands an understanding of the host immune response against a pathogen. Immune-based therapy is an effective treatment option for malignancies and infectious diseases. A promising therapeutic approach to improve the clinical outcome of malignancies is the blockade of immune checkpoints. Immune checkpoints refer to a wide range of inhibitory or regulatory pathways that are critical for maintaining self-tolerance and modulating the immune response. Programmed cell-death protein-1 (PD-1), programmed cell death ligand-1 (PD-L1), cytotoxic T-lymphocyte-associated protein 4, and lymphocyte-activation gene-3 are the most important immune checkpoint molecules. Several pathogens, including M. leprae, are supposed to utilize these mechanisms to evade the host immune response. Regulatory T cells and expression of co-inhibitory molecules on lymphocytes induce specific T-cell anergy/exhaustion, leading to disseminated and progressive disease. From this perspective, we outline how the co-inhibitory molecules PD-1, PD-L1, and Th1/Th17 versus Th2/Treg cells are balanced, how antigen-presenting cell maturation acts at different levels to inhibit T cells and modulate the development of leprosy, and how new interventions interfere with leprosy development.

Recognition of Candida albicans by gingival fibroblasts: The role of TLR2, TLR4/CD14, and MyD88

Recent evidence indicates that nonprofessional immune cells such as epithelial cells, endothelial cells, and fibroblasts also contribute to innate immunity via secretion of cytokines. Fibroblasts are the principal type of cell found in the periodontal connective tissues and they are involved in the immune response during periodontal disease. The role of fibroblasts in the recognition of pathogens via Toll-like receptors (TLRs) has been established; however, few studies have been conducted concerning the involvement of innate immune receptors in the recognition of Candida albicans by gingival fibroblast. In the current study, we investigate the functional activity of TLR2, cluster of differentiation 14 (CD14), and myeloid differentiation primary response gene 88 (MyD88) molecules in the recognition of C. albicans by gingival fibroblast. First, we identified that gingival fibroblasts expressed TLR2, TLR3, and TLR4. Our results showed that TLR agonists had no effect on these receptors' expression by TLR2, MyD88, and CD14-deficient cells. Notably, C. albicans and a synthetic triacylated lipoprotein (Pam3CSK4) induced a remarkable increase of TLR3 expression on MyD88-deficient gingival fibroblasts. TLR4 expression levels were lower than TLR2 and TLR3 levels and remained unchanged after TLR agonist stimulation. Gingival fibroblasts presented morphological similarities; however, TLR2 deficiency on these cells leads to a lower proliferative response, whereas the deficiency on CD14 expression resulted in lower levels of type I collagen by these cells. In addition, the recognition of C. albicans by gingival fibroblasts had an effect on the secretion of cytokines and it was dependent on a specific recognition molecule. Specifically, tumor necrosis factor-α (TNF-α) production after the recognition of C. albicans was dependent on MyD88, CD14, and TLR2 molecules, whereas the production of interleukin-1β (IL-1β) and IL-13 was dependent on TLR2. These findings are the first to describe a role of gingival fibroblast in the recognition of C. albicans and the pathways involved in this process. An understanding of these pathways may lead to alternative treatments for patients with periodontal disease.

Effects of budlein A on human neutrophils and lymphocytes

OBJECTIVE

In this study, we evaluated whether budlein A modulates the activation of innate and adaptive immune cells such as neutrophils and lymphocytes.

MATERIAL AND METHODS

Our research group has investigated several plant species and several compounds have been isolated, identified, and their medical potential evaluated. Budlein A is a SL isolated from the species Aldama buddlejiformis and A. robusta (Asteraceae) and shows anti-inflammatory and anti-nociceptive activities. Advances in understanding how plant-derived substances modulate the activation of innate and adaptive immune cells have led to the development of new therapies for human diseases.

RESULTS

Budlein A inhibited MPO activity, IL-6, CXCL8, IL-10, and IL-12 production and induces neutrophil apoptosis. In contrast, budlein A inhibited lymphocyte proliferation and IL-2, IL-10, TGF-β, and IFN-γ production, but it did not lead to cell death.

CONCLUSIONS

Collectively, our results indicate that budlein A shows distinct immunomodulatory effects on immune cells.

Tracheal Smooth Muscle Cells Stimulated by Stem Cell Factor-c-Kit Coordinate the Production of Transforming Growth Factor-β1 and Fibroblast Growth Factor-2 Mediated by Chemokine (C-C Motif) Ligand 3

The aim of this study was to evaluate the mechanism involved in the stem cell factor (SCF)-induced production of fibroblast growth factor-2 (FGF-2), transforming growth factor-β1 (TGF-β1), and chemokine (C-C motif) ligand 3 (CCL3) in tracheal smooth muscle cells (tSMCs) and the signaling pathway involved in the process. tSMC primary cultures were stimulated with SCF and evaluated at 24 h. Cells treated with specific antibodies did not show any immunolabeling for cytokeratin or fibroblast activation protein, but were positive for α-smooth muscle actin, indicating the purity of the primary cell line. Western blot analysis showed constitutive phosphorylation of c-Kit, as well as increased total protein and phosphorylated c-Kit levels in tSMCs after SCF stimulation. Flow cytometry analysis also showed an increase in cell-surface c-Kit expression in the presence of SCF. SCF induced TGF-β mRNA expression in tSMCs, as well as the production of TGF-β1, CCL3, and FGF-2. Pretreatment with anti-CCL3 antibody blocked TGF-β1 expression and partially inhibited FGF-2 production. On the other hand, anti-c-Kit antibody blocked TGF-β1 expression and FGF-2 production. Thus, TGF-β1 and FGF-2 production were mediated by CCL3 production through c-Kit. Pretreatment with mitogen-activated protein kinase kinase 1, p38, and Jun N-terminal kinase inhibitors showed that the effects mediated by SCF were involved with the modulation of mitogen-activated protein kinase (MAPK) pathways. Development of inhibitors targeting CCL3 through MAPK activation could thus be an attractive strategy to inhibit tSMC activation during asthma.

Proteomics of Secretory-Stage and Maturation-Stage Enamel of Genetically Distinct Mice

The mechanisms by which excessive ingestion of fluoride (F) during amelogenesis leads to dental fluorosis (DF) are still not precisely known. Inbred strains of mice vary in their susceptibility to develop DF, and therefore permit the investigation of underlying molecular events influencing DF severity. We employed a proteomic approach to characterize and evaluate changes in protein expression from secretory-stage and maturation-stage enamel in 2 strains of mice with different susceptibilities to DF (A/J, i.e. ‘susceptible' and 129P3/J, i.e. ‘resistant'). Weanling male and female susceptible and resistant mice fed a low-F diet were divided into 2 F-water treatment groups. They received water containing 0 (control) or 50 mg F/l for 6 weeks. Plasma and incisor enamel was analyzed for F content. For proteomic analysis, the enamel proteins extracted for each group were separated by 2-dimensional electrophoresis and subsequently characterized by liquid-chromatography electrospray-ionization quadrupole time-of-flight mass spectrometry. F data were analyzed by 2-way ANOVA and Bonferroni's test (p < 0.05). Resistant mice had significantly higher plasma and enamel F concentrations when compared with susceptible mice in the F-treated groups. The proteomic results for mice treated with 0 mg F/l revealed that during the secretory stage, resistant mice had a higher abundance of proteins than their susceptible counterparts, but this was reversed during the maturation stage. Treatment with F greatly increased the number of protein spots detected in both stages. Many proteins not previously described in enamel (e.g. type 1 collagen) as well as some uncharacterized proteins were identified. Our findings reveal new insights regarding amelogenesis and how genetic background and F affect this process.

Activation and cytokine profile of monocyte derived dendritic cells in leprosy: in vitro stimulation by sonicated Mycobacterium leprae induces decreased level of IL-12p70 in lepromatous leprosy

Dendritic cells (DCs) play a pivotal role in the connection of innate and adaptive immunity of hosts to mycobacterial infection. Studies on the interaction of monocyte-derived DCs (MO-DCs) using Mycobacterium leprae in leprosy patients are rare. The present study demonstrated that the differentiation of MOs to DCs was similar in all forms of leprosy compared to normal healthy individuals. In vitro stimulation of immature MO-DCs with sonicated M. leprae induced variable degrees of DC maturation as determined by the increased expression of HLA-DR, CD40, CD80 and CD86, but not CD83, in all studied groups. The production of different cytokines by the MO-DCs appeared similar in all of the studied groups under similar conditions. However, the production of interleukin (IL)-12p70 by MO-DCs from lepromatous (LL) leprosy patients after in vitro stimulation with M. leprae was lower than tuberculoid leprosy patients and healthy individuals, even after CD40 ligation with CD40 ligand-transfected cells. The present cumulative findings suggest that the MO-DCs of LL patients are generally a weak producer of IL-12p70 despite the moderate activating properties ofM. leprae. These results may explain the poor M. leprae-specific cell-mediated immunity in the LL type of leprosy.

IL-4/CCL22/CCR4 axis controls regulatory T-cell migration that suppresses inflammatory bone loss in murine experimental periodontitis

Inflammatory bone resorption is a hallmark of periodontitis, and Tregs and Th2 cells are independently associated with disease progression attenuation. In this study, we employed an infection-triggered inflammatory osteolysis model to investigate the mechanisms underlying Treg and Th2 cell migration and the impact on disease outcome. Aggregatibacter actinomycetemcomitans-infected C57Bl/6 (wild-type [WT]) mice develop an intense inflammatory reaction and alveolar bone resorption, and Treg and Th2 cell migration is temporally associated with disease progression attenuation. Tregs extracted from the lesions preferentially express CCR4 and CCR8, whereas Th2 cells express CCR3, CCR4, and CCR8. The absence of CCR5 and CCR8 did not significantly impact the migration of Tregs and Th2 cells or affect the disease outcome. CCR4KO mice presented a minor reduction in Th2 cells in parallel with major impairment of Treg migration, which was associated with increased inflammatory bone loss and higher proinflammatory and osteoclastogenic cytokine levels. The blockade of the CCR4 ligand CCL22 in WT mice resulted in an increased inflammatory bone loss phenotype similar to that in the CCR4KO strain. Adoptive transfer of CCR4(+) Tregs to the CCR4KO strain revert the increased disease phenotype to WT mice-like levels; also, the in situ production of CCL22 in the lesions is mandatory for Tregs migration and the consequent bone loss arrest. The local release of exogenous CCL22 provided by poly(lactic-co-glycolic acid) (PLGA) microparticles promotes migration of Tregs and disease arrest in the absence of endogenous CCL22 in the IL-4KO strain, characterized by the lack of endogenous CCL22 production, defective migration of Tregs, and exacerbated bone loss. In summary, our results show that the IL-4/CCL22/CCR4 axis is involved in the migration of Tregs to osteolytic lesion sites, and attenuates development of lesions by inhibiting inflammatory migration and the production of proinflammatory and osteoclastogenic mediators.

Randomized controlled clinical trial of long-term chemo-mechanical caries removal using Papacarie™ gel

OBJECTIVES

Compare the effectiveness of Papacarie™ gel for the chemo-mechanical removal of carious lesions on primary teeth to conventional caries removal with a low-speed bur with regard to execution time, clinical aspects and radiographic findings.

MATERIAL AND METHODS

A randomized controlled clinical trial with a split-mouth design was carried out. The sample was composed of 20 children aged four to seven years, in whom 40 deciduous teeth were randomly divided into two groups: chemo-mechanical caries removal with Papacarie™ and removal of carious dentin with a low-speed bur. Each child underwent both procedures and served as his/her own control. Restorations were performed with glass ionomer cement. The time required to perform the procedure was also analyzed. The patients underwent longitudinal clinical and radiographic follow-up of the restorations.

RESULTS

No statistically significant difference between groups was found regarding the time required to perform the procedures and the radiographic follow up. Statistically significant differences between groups were found in the clinical evaluation at 6 and 18 months after treatment.

CONCLUSION

Papacarie™ is as effective as the traditional method for the removal of carious dentin on deciduous teeth, but offers the advantages of the preservation of sound dental tissue as well as the avoidance of sharp rotary instruments and local anesthesia.

Inflammasome activation is critical to the protective immune response during chemically induced squamous cell carcinoma

Chronic inflammation affects most stages of tumorigenesis, including initiation, promotion, malignant differentiation, invasion and metastasis. Inflammasomes have been described as involved with persistent inflammation and are known to exert both pro and antitumour effects. We evaluated the influence of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and caspase (CASP)-1 in the antitumor immune response using a multistage model of squamous cell carcinoma (SCC) development. Absence of ASC and CASP-1 resulted in an earlier incidence and increased number of papilloma. Loss of inflammassome function in mice resulted in decreased presence of natural killer (NK), dendritic (DC), CD4⁺, CD8⁺ and CD45RB⁺ T cells in the tumor lesions as well as in lymph nodes (LN) compared with WT mice. Increased percentage of CD4⁺CD25⁺Foxp3⁺ T cells was associated with association with inflammasome loss of function. Moreover, significant differences were also found with neutrophils and macrophage infiltrating the lesions. Myeloperoxidase (MPO), but not elastase (ELA), activity oscillated among the groups during the SCC development. Levels of proinflammatory cytokines IL-1β, IL-18, Tumor Necrosis Factor (TNF)-α and Interferon (IFN)-γ were decreased in the tumor microenvironment in the absence of inflammasome proteins. These observations suggest a link between inflammasome function and SCC tumorigenesis, indicating an important role for inflammasome activation in the control of SCC development.

Regulatory T cells in the actinic cheilitis

BACKGROUND

Actinic cheilitis (AC) is an oral potentially malignant lesion which is the counterpart of actinic keratosis of the skin and has potential to develop into squamous cell carcinoma. Regulatory T cells (Tregs) have a critical role in modulating the antitumor immune responses. The presence of regulatory T cells in potentially malignant lesions has not been described. We chose investigate the involvement of regulatory T cells in potentially malignant lesions.

METHODS

The frequency, phenotype, and activity of CD4+CD25+ T cells isolated from blood and lesion of AC patients were analyzed by flow cytometry. Cytokines were quantified by ELISA. Data were compared with samples from healthy subjects.

RESULTS

The frequency and suppressor activity of circulating CD4+CD25+ T cells was similar in AC patients and control subjects. However, the frequencies of IL-10-positive Tregs were higher in AC patients, and these cells inhibited interferon-gamma (IFN-γ) and increased interleukin (IL)-10 productions in co-cultures. Furthermore, CD4+CD25+ T cells accumulate in AC lesions. Lesions-derived regulatory T cells suppressed lymphocyte proliferation and pro-inflammatory cytokine production. Moreover, high levels of IL-10 and transforming growth factor-β (TGF-β), and low IFN-γ were detected in the potentially malignant lesions.

CONCLUSION

Therefore, our data show that Tregs accumulate in AC lesions, and these cells could be suppressing immune responses in a potentially malignant microenvironment.

Efficacy of Papacarie(®) in reduction of residual bacteria in deciduous teeth: a randomized, controlled clinical trial

OBJECTIVES

The aim of the present study was to analyze the efficacy of Papacarie(®) gel compared with the traditional method (low-speed bur) in reducing the counts of total bacteria, Lactobacillus, total Streptococcus and Streptococcus mutans group.

METHODS

A randomized, controlled clinical trial with a split-mouth design was performed. The sample comprised 40 deciduous teeth in 20 children (10 males and 10 females) aged four to seven years. The teeth were randomly allocated to two groups: G1, or chemomechanical caries removal with Papacarie Duo(®), and G2, or the removal of carious dentin tissue with a low-speed bur. Infected dentin was collected prior to the procedure, and the remaining dentin was collected immediately following the removal of the carious tissue. Initial and final counts of bacterial colonies were performed to determine whether there was a reduction in the number of colony-forming units (CFUs) of each microorganism studied. ClinicalTrials.gov: NCT01811420.

RESULTS

Reductions were found in the numbers of total bacteria, total Streptococcus and Streptococcus mutans group following either of the caries removal methods (p<0.05). A reduction was also noted in the number of Lactobacillus CFUs; however, this difference did not achieve statistical significance (p>0.05).

CONCLUSION

Papacarie(®) is an excellent option for the minimally invasive removal of carious tissue, achieving significant reductions in total bacteria, total Streptococcus and S. mutans with the same effectiveness as the traditional caries removal method.

CCL3 and CXCL12 production in vitro by dental pulp fibroblasts from permanent and deciduous teeth stimulated by Porphyromonas gingivalis LPS

OBJECTIVE

The aim of this study was to compare the production of the chemokines CCL3 and CXCL12 by cultured dental pulp fibroblasts from permanent (PDPF) and deciduous (DDPF) teeth under stimulation by Porphyromonas gingivalis LPS (PgLPS).

MATERIAL AND METHODS

Primary culture of fibroblasts from permanent (n=3) and deciduous (n=2) teeth were established using an explant technique. After the fourth passage, fibroblasts were stimulated by increasing concentrations of PgLPS (0-10 µg/mL) at 1, 6 and 24 h. The cells were tested for viability through MTT assay, and production of the chemokines CCL3 and CXCL12 was determined through ELISA. Comparisons among samples were performed using One-way ANOVA for MTT assay and Two-way ANOVA for ELISA results.

RESULTS

Cell viability was not affected by the antigen after 24 h of stimulation. PgLPS induced the production of CCL3 by dental pulp fibroblasts at similar levels for both permanent and deciduous pulp fibroblasts. Production of CXCL12, however, was significantly higher for PDPF than DDPF at 1 and 6 h. PgLPS, in turn, downregulated the production of CXCL12 by PDPF but not by DDPF.

CONCLUSION

These data suggest that dental pulp fibroblasts from permanent and deciduous teeth may present a differential behavior under PgLPS stimulation.

Increased hepcidin expression in multibacillary leprosy

Iron is essential for all organisms and its availability can control the growth of microorganisms; therefore, we examined the role of iron metabolism in multibacillary (MB) leprosy, focusing on the involvement of hepcidin. Erythrograms, iron metabolism parameters, pro-inflammatory cytokines and urinary hepcidin levels were evaluated in patients with MB and matched control subjects. Hepcidin expression in MB lesions was evaluated by quantitative polymerase chain reaction. The expression of ferroportin and hepcidin was evaluated by immunofluorescence in paucibacillary and MB lesions. Analysis of hepcidin protein levels in urine and of hepcidin mRNA and protein levels in leprosy lesions and skin biopsies from healthy control subjects showed elevated hepcidin levels in MB patients. Decreases in haematologic parameters and total iron binding capacity were observed in patients with MB leprosy. Moreover, interleukin-1 beta, ferritin, soluble transferrin receptor and soluble transferrin receptor/log ferritin index values were increased in leprosy patients. Hepcidin was elevated in lepromatous lesions, whereas ferroportin was more abundant in tuberculoid lesions. In addition, hepcidin and ferroportin were not colocalised in the biopsies from leprosy lesions. Anaemia was not commonly observed in patients with MB; however, the observed changes in haematologic parameters indicating altered iron metabolism appeared to result from a mixture of anaemia of inflammation and iron deficiency. Thus, iron sequestration inside host cells might play a role in leprosy by providing an optimal environment for the bacillus.

In vitro regulation of CCL3 and CXCL12 by bacterial by-products is dependent on site of origin of human oral fibroblasts

INTRODUCTION

Production of chemokines by tissue resident cells is one of the main mechanisms involved in the inflammatory infiltrate formation during inflammation. The specific ability of fibroblasts from different oral tissues such as gingiva, periodontal ligament, and dental pulp from permanent and deciduous teeth in producing the chemokines CCL3 and CXCL12 under stimulation by bacterial products commonly found in endodontic infections was investigated.

METHODS

Cultures of fibroblasts from gingiva and periodontal ligament as well as from dental pulp from permanent and deciduous teeth were established by using an explant technique and stimulated with increasing concentrations of Escherichia coli lipopolysaccharide (EcLPS) and Enterococcus faecalis lipoteichoic acid (EfLTA) for 1, 6, and 24 hours. Supernatants were tested for CCL3 and CXCL12 by enzyme-linked immunosorbent assay.

RESULTS

In general, CCL3 production was induced by EcLPS in the 4 fibroblast subtypes and by EfLTA in fibroblasts from gingiva and periodontal ligament. Constitutive CXCL12 synthesis decreased in all fibroblast subtypes especially under stimulation with EcLPS. Fibroblast from permanent deciduous teeth was the cell type presenting the most expressive reduction in CXCL12 release by both stimuli. On the basis of computational matching of CXCL12 mRNA with the microRNAs miR-141 and miR-200a, their expression was also investigated. Although detected in the fibroblasts, these molecules remained unaltered by bacterial by-product stimulation.

CONCLUSIONS

EcLPS and EfLTA induced the production of CCL3 and unbalanced the synthesis of CXCL12 in a manner dependent on the specific tissue origin of fibroblasts.

PD-1 blockage delays murine squamous cell carcinoma development

Engagement of programmed death-1 (PD-1) with its two ligands [programmed death ligand-1 (PD-L1) and PD-L2] has been associated with the suppression of tumor-reactive T cells; however, the underlying mechanism for this T-cell dysfunction is not clear. We hypothesized that PD-1 and PD-L1 signals are, in part, responsible for squamous cell carcinoma (SCC) escape from immune antitumor regulation by modulation of the tumor environment. In the present study, we used a multistage model of SCC to examine the role of PD-1/PD-L1 activation during tumor development. Tumor sites presented an increased percentage of CD4(+) and CD8(+) T cells expressing PD-1 when compared with non-tumorigenic control mice, whereas the expression of PD-L1 was particularly increased in F4/80(+) macrophages in tumor sites. Further, the systemic immune neutralization of PD-1 resulted in a decreased number and delayed incidence rate of papillomas followed by a differential expression of cytokeratins, suggesting that the PD-1-PD-L1 interaction contributes to the progression of SCC by downregulation of antitumor responses. In fact, blocking PD-1 increased the percentage of CD8(+) and CD4(+) T cells, and the levels of interferon-γ in the tumor sites. Our results indicated involvement of PD-1(+) T cells in SCC development and in the modulation of the inflammatory immune response.

Antimicrobial activity of calcium hydroxide and chlorhexidine on intratubular Candida albicans

This study investigated the efficacy of calcium hydroxide and chlorhexidine gel for the elimination of intratubular Candida albicans (C. albicans). Human single-rooted teeth contaminated with C. albicans were treated with calcium hydroxide, 2% chlorhexidine gel, calcium hydroxide plus 2% chlorhexidine gel, or saline (0.9% sodium chloride) as a positive control. The samples obtained at depths of 0–100 and 100–200 µm from the root canal system were analyzed for C. albicans load by counting the number of colony forming units and for the percentage of viable C. albicans using fluorescence microscopy. First, the antimicrobial activity of calcium hydroxide and the 2% chlorhexidine gel was evaluated by counting the number of colony forming units. After 14 days of intracanal medication, there was a significant decrease in the number of C. albicans colony forming units at a depth of 0–100 µm with chlorhexidine treatment either with or without calcium hydroxide compared with the calcium hydroxide only treatment. However, there were no differences in the number of colony forming units at the 100–200 µm depth for any of the medications investigated. C. albicans viability was also evaluated by vital staining techniques and fluorescence microscopy analysis. Antifungal activity against C. albicans significantly increased at both depths in the chlorhexidine groups with and without calcium hydroxide compared with the groups treated with calcium hydroxide only. Treatments with only chlorhexidine or chlorhexidine in combination with calcium hydroxide were effective for elimination of C. albicans.

Evidence supporting a protective role for th9 and th22 cytokines in human and experimental periapical lesions

INTRODUCTION

The development of periapical granulomas is dependent on the host response and involves Th1, Th2, Th17, and Treg-related cytokines. The discovery of new Th9 and Th22 subsets, with important immunomodulatory roles mediated by interleukin (IL)-9 and IL-22, respectively, emphasizes the need for reevaluation of current cytokine paradigms in context of periapical lesions. We investigated the expression of IL-9 and IL-22 in active and stable human granulomas and throughout experimental lesion development in mice.

METHODS

Periapical granulomas (N = 83) and control specimens (N = 24) were evaluated regarding the expression of IL-9 and IL-22 via real-time polymerase chain reaction. Experimental periapical lesions were induced in mice (pulp exposure and bacterial inoculation) and the lesions evolution correlation with IL-9 and IL-22 expression kinetics was evaluated.

RESULTS

IL-9 and IL-22 mRNA expression was higher in periapical lesions than in control samples; higher levels of IL-9 and IL-22 were observed in inactive than in active lesions. In the experimental lesions model, increasing levels of IL-9 and IL-22 mRNA were detected in the lesions, and inverse correlations were found between IL-9 and IL-22 and the increase of lesion area in the different time point intervals.

CONCLUSIONS

Our results suggest that Th9 and Th22 pathways may contribute to human and experimental periapical lesion stability.

Inflammatory events during murine squamous cell carcinoma development

Background

Squamous cell carcinoma (SCC) is one of the most common human cancers worldwide. In SCC, tumour development is accompanied by an immune response that leads to massive tumour infiltration by inflammatory cells, and consequently, local and systemic production of cytokines, chemokines and other mediators. Studies in both humans and animal models indicate that imbalances in these inflammatory mediators are associated with cancer development.

Methods

We used a multistage model of SCC to examine the involvement of elastase (ELA), myeloperoxidase (MPO), nitric oxide (NO), cytokines (IL-6, IL-10, IL-13, IL-17, TGF-β and TNF-α), and neutrophils and macrophages in tumour development. ELA and MPO activity and NO, IL-10, IL −17, TNF-α and TGF-β levels were increased in the precancerous microenvironment.

Results

ELA and MPO activity and NO, IL-10, IL −17, TNF-α and TGF-β levels were increased in the precancerous microenvironment. Significantly higher levels of IL-6 and lower levels of IL-10 were detected at 4 weeks following 7,12-Dimethylbenz(a)anthracene (DMBA) treatment. Similar levels of IL-13 were detected in the precancerous microenvironment compared with control tissue. We identified significant increases in the number of GR-1⁺ neutrophils and F4/80⁺/GR-1^- infiltrating cells in tissues at 4 and 8 weeks following treatment and a higher percentage of tumour-associated macrophages (TAM) expressing both GR-1 and F4/80, an activated phenotype, at 16 weeks. We found a significant correlation between levels of IL-10, IL-17, ELA, and activated TAMs and the lesions. Additionally, neutrophil infiltrate was positively correlated with MPO and NO levels in the lesions.

Conclusion

Our results indicate an imbalance of inflammatory mediators in precancerous SCC caused by neutrophils and macrophages and culminating in pro-tumour local tissue alterations.

Non-inflammatory destructive periodontal disease: a clinical, microbiological, immunological and genetic investigation

Periodontitis comprises a group of multifactorial diseases in which periodontopathogens accumulate in dental plaque and trigger host chronic inflammatory and immune responses against periodontal structures, which are determinant to the disease outcome. Although unusual cases of non-inflammatory destructive periodontal disease (NIDPD) are described, their pathogenesis remains unknown. A unique NIDPD case was investigated by clinical, microbiological, immunological and genetic tools. The patient, a non-smoking dental surgeon with excessive oral hygiene practice, presented a generalized bone resorption and tooth mobility, but not gingival inflammation or occlusion problems. No hematological, immunological or endocrine alterations were found. No periodontopathogens (A. actinomycetemcomitans, P. gingivalis, F. nucleatum and T. denticola) or viruses (HCMV, EBV-1 and HSV-1) were detected, along with levels of IL-1β and TNF-a in GCF compatible with healthy tissues. Conversely ALP, ACP and RANKL GCF levels were similar to diseased periodontal sites. Genetic investigation demonstrated that the patient carried some SNPs, as well HLA-DR4 (*0404) and HLA-B27 alleles, considered risk factors for bone loss. Then, a less vigorous and diminished frequency of toothbrushing was recommended to the patient, resulting in the arrest of alveolar bone loss, associated with the return of ALP, ACP and RANKL in GCF to normality levels. In conclusion, the unusual case presented here is compatible with the previous description of NIDPD, and the results that a possible combination of excessive force and frequency of mechanical stimulation with a potentially bone loss prone genotype could result in the alveolar bone loss seen in NIDPD.

Antimicrobial peptides and nitric oxide production by neutrophils from periodontitis subjects

Neutrophils play an important role in periodontitis by producing nitric oxide (NO) and antimicrobial peptides, molecules with microbicidal activity via oxygen-dependent and -independent mechanisms, respectively. It is unknown whether variation in the production of antimicrobial peptides such as LL-37, human neutrophil peptides (HNP) 1-3, and NO by neutrophils influences the pathogenesis of periodontal diseases. We compared the production of these peptides and NO by lipopolysaccharide (LPS)-stimulated neutrophils isolated from healthy subjects and from patients with periodontitis. Peripheral blood neutrophils were cultured with or without Aggregatibacter actinomycetemcomitans-LPS (Aa-LPS), Porphyromonas gingivalis-LPS (Pg-LPS) and Escherichia coli-LPS (Ec-LPS). qRT-PCR was used to determine quantities of HNP 1-3 and LL-37 mRNA in neutrophils. Amounts of HNP 1-3 and LL-37 proteins in the cell culture supernatants were also determined by ELISA. In addition, NO levels in neutrophil culture supernatants were quantitated by the Griess reaction. Neutrophils from periodontitis patients cultured with Aa-LPS, Pg-LPS and Ec-LPS expressed higher HNP 1-3 mRNA than neutrophils from healthy subjects. LL-37 mRNA expression was higher in neutrophils from patients stimulated with Aa-LPS. Neutrophils from periodontitis patients produced significantly higher LL-37 protein levels than neutrophils from healthy subjects when stimulated with Pg-LPS and Ec-LPS, but no difference was observed in HNP 1-3 production. Neutrophils from periodontitis patients cultured or not with Pg-LPS and Ec-LPS produced significantly lower NO levels than neutrophils from healthy subjects. The significant differences in the production of LL-37 and NO between neutrophils from healthy and periodontitis subjects indicate that production of these molecules might influence individual susceptibility to important periodontal pathogens.

The pattern recognition receptors expressed on neutrophils and the associated cytokine profile from different aged patients with Candida-related denture stomatitis

This study evaluated the expression of pattern recognition receptors (PRRs) and activation factors associated with salivary and blood neutrophils from different aged patients diagnosed with Candida-related denture stomatitis (DS). Expression of neutrophil PRRs was determined by flow cytometry and immunofluorescence, and the levels of selected cytokines that influence immune activation were determined by ELISA. The salivary (but not the serum derived) neutrophils of individuals with DS were found to have an increased expression of CD69 regardless of the age of the patient compared to patients without DS. However, these salivary neutrophils had a lower expression of CD66b and CD64. Expression of TLR2 was lower on the salivary- and serum-derived neutrophils from elderly individuals compared to the neutrophils of younger subjects, regardless of whether the individual had DS. Salivary interleukin (IL)-4 was elevated in both of the elderly subject groups (with or without DS). Only elderly DS patients were observed to have increased serum IL-4 levels and reduced salivary IL-12 levels. Younger DS patients showed an increase in salivary IL-10 levels, and both the saliva and the serum levels of IFN-γ were increased in all of the younger subjects. Our data demonstrated that changes in both the oral immune cells and the protein components could be associated with DS. Furthermore, changes in the blood-derived factors were more associated with age than DS status.

TNF-alpha modulates alveolar bone repair under homeostatic conditions in mice (44.1)

Cytokines have been implicated in the pathogenesis of bone diseases, but its role in bone repair process remains unknown. Our objective was to characterize the role of TNF-alpha in alveolar bone healing after tooth extraction in mice. Following the extraction of the right upper incisor of C57Bl/6(WT) and TNFp55KO strains, the maxilla containing the remaining alveolus was collected for histomorphometric and molecular (RealTimePCR) analysis. In WT mice the initial formation of clot was followed by the transient inflammatory infiltrate and a granulation tissue, gradually substituted by bone. In WT mice TNF-a mRNA was detected with an initial peak at 7 days, followed by a decreasing expression over time and a second peak at 28 days. Bone markers expression presented an initial high expression of COL-I, followed by CBFA-1 and ALP and subsequently by OCN and PHEX. TNFp55KO strain presented a delayed angiogenesis and osteogenesis processes, increased inflammatory reaction, despite of a decrease in CXCL1, CCL-2 and CCL3 levels; and increased COL-I mRNA levels and decreased CBFA-1, ALP, OCN and PHEX expression. The results presented here demonstrate that the absence of TNF-alpha interferes in alveolar bone repair through mechanisms that involve the modulation of inflammatory cell migration and osteogenic markers expression during the course of alveolar bone repair.

CD25+ T cell depletion impairs murine squamous cell carcinoma development via modulation of antitumor immune responses

Squamous cell carcinoma (SCC) constitutes a microenvironment that could modulate the antitumor immune response. Also, tumor-infiltrating lymphocytes are believed to play complex regulatory roles in antitumor immunity against SCC. The presence of regulatory T cells (Tregs) has been associated with the suppression of tumor-reactive T cells. However, the underlying mechanism for this T cell dysfunction is not clear. We used a multistage model of SCC to examine the role of Treg cells during tumor development. 7,12-dimethylbenz[a]-anthracene/phorbol 12-myristate 13-acetate treatment and systemic depletion of Treg cells using an anti-CD25 monoclonal antibody (PC61) resulted in a decrease in the number and incidence of papilloma. Furthermore, CD25 depletion increased the proportion of CD8(+) and CD4(+) T cells that were isolated from tumor lesions. The levels of interleukin (IL)-1β, IL-10, IL-12, IL-13, interferon-γ, transforming growth factor-β and tumor necrosis factor-α, but not IL-17, were increased in the tumor microenvironment after Treg depletion. Therefore, our results indicated involvement of CD25(+) T cells in SCC development and in the suppression of the inflammatory immune response.

The use of chronic gingivitis as reference status increases the power and odds of periodontitis genetic studies: a proposal based in the exposure concept and clearer resistance and susceptibility phenotypes definition

AIM

Current literature on chronic periodontitis genetics encompasses numerous single nucleotide polymorphisms-focused case-control studies with inconsistent and controversial results, which typically disregards the exposure concept embraced by case-control definition. Herein, we propose a case-control design reappraisal by clear phenotype selection, where chronic gingivitis represents a genetically resistant phenotype/genotype opposing the susceptible cohort.

MATERIAL AND METHODS

The hypothesis was tested in healthy, chronic periodontitis and gingivitis groups through Real-time PCR-based allelic discrimination of classic variants IL1B-3954, IL6-174, TNFA-308, IL10-592 and TLR4-299.

RESULTS

Observed allele/genotype frequencies characterize the healthy group with an intermediate genetic profile between periodontitis and gingivitis cohorts. When comparing genotype/allele frequencies in periodontitis versus healthy and periodontitis versus gingivitis scenarios, the number of positive associations (2-4) and the degree of association (p and odds ratio values) were significantly increased by the new approach proposed (periodontitis versus gingivitis), suggesting the association of IL1B-3954, TNFA-308, IL10-592 and TLR4-299 with periodontitis risk. Power study was also significantly improved by the new study design proposed when compared to the traditional approach.

CONCLUSIONS

The data presented herein support the use of new case-control study design based on the case-control definition and clear resistance/susceptibility phenotypes selection, which can significantly impact the study power and odds of identification of genetic factors involved in PD.

Dose-response met-RANTES treatment of experimental periodontitis: a narrow edge between the disease severity attenuation and infection control

Chemokines and chemokine receptors have been implicated in the selective migration of leukocyte subsets to periodontal tissues, which consequently influences the disease outcome. Among these chemoattractants, the chemokines CCL3, CCL4 and CCL5 and its receptors, CCR1 and CCR5, have been associated with increased disease severity in mice and humans. Therefore, in this study we investigated the modulation of experimental periodontitis outcome by the treatment with a specific antagonist of CCR1 and 5 receptors, called met-RANTES. C57Bl/6 mice was orally infected with Aggregatibacter actinomycetemcomitans and treated with 0.05, 0.1, 0.5, 1.5 and 5 mg doses of met-RANTES on alternate days, and evaluated by morphometric, cellular, enzymatic and molecular methods. At 0.5 mg up to 5 mg doses, a strong reduction in the alveolar bone loss and inflammatory cell migration were observed. Interestingly, 5 mg dose treatment resulted in the maximum inhibition of inflammatory cell migration, but resulted in a similar inhibition of bone loss when compared with the lower doses, and also resulted in increased bacterial load and CRP response. When 0.5 and 5 mg therapy regimens were compared it was observed that both therapeutic protocols were able to downregulate the levels of pro-inflammatory, Th1-type and osteoclastogenic cytokines, and CD3+ and F4/80+ cells migration to periodontal tissues, but the high dose modulates host response in a more pronounced and unspecific and excessive way, interfering also with the production of antimicrobial mediators such as MPO, iNOS and IgG, and with GR1+ and CD19+ cells migration. Our results demonstrate a thin line between beneficial immunoregulation and impaired host defense during experimental periodontitis, and the determination of the exact equilibrium point is mandatory for the improvement of immune-targeted therapy of periodontitis.

Enhanced programmed death 1 (PD-1) and PD-1 ligand (PD-L1) expression in patients with actinic cheilitis and oral squamous cell carcinoma

PD-1 and PD-L1 can be involved in tumor escape, and little is known about the role of these molecules in oral tumors or pre-malignant lesions. In the present study, we investigated the expression of PD-1 and PD-L1 in the blood and lesion samples of patients with actinic cheilitis (AC) and oral squamous cell carcinoma (OSCC). Our results showed that lymphocytes from peripheral blood and tissue samples exhibited high expression of PD-1 in both groups analyzed. Patients with AC presented higher percentage as well as the absolute numbers of CD4+PD-1+ and CD8+PD-1+ lymphocytes in peripheral blood mononuclear cells (PBMC) than healthy individuals, while patients with OSCC presented an increased frequency of CD8+PD1+ in PBMC when compared with controls. On the other hand, increased frequency of CD4+ and CD8+ T cells expressing PD-1(+) accumulate in samples from OSCC, and the expression of PD-L1 was intense in OSCC and moderate in AC lesion sites. Lower levels of IFN-γ and higher levels of TGF-β were detected in OSCC samples. Our data demonstrate that PD-1 and PD-L1 molecules are present in blood and samples of AC and OSCC patients. Further studies are required to understand the significance of PD-1 and PD-L1 in oral tumors microenvironment.

Chlorogenic acids from Tithonia diversifolia demonstrate better anti-inflammatory effect than indomethacin and its sesquiterpene lactones

ETHNOPHARMACOLOGICAL RELEVANCE

T. diversifolia (Hemsl.) A. Gray (Asteraceae) has been used in the traditional medicine in several countries as anti-inflammatory and against other illnesses. It is important to evaluate the anti-inflammatory activity of extracts from the leaves of this species, including an infusion, to identify the main constituents of the extracts, observe their effects and correlate them with the anti-inflammatory activity.

MATERIALS AND METHODS

An infusion, a leaf rinse extract (LRE) and a polar extract from the rinsed leaves (PE) were obtained and analysed by HPLC-UV-DAD and infrared spectroscopy. The major compounds of these extracts were quantified. The three obtained extracts were evaluated for their anti-inflammatory activities using the paw oedema and croton oil ear oedema assays in mice. Furthermore, neutrophil migration was measured by evaluating myeloperoxidase activity.

RESULTS

The PE consists primarily of chlorogenic acids (CAs) and lacks sesquiterpene lactones (STLs). The LRE is rich in STLs and includes a few flavonoids. The infusion is chemically similar to the PE but also contains very low amounts of STLs. The PE and LRE have better mechanisms of action than non-steroidal anti-inflammatory drugs (NSAIDs). Unlike NSAIDs, both the PE and LRE inhibit oedema and neutrophil migration. The pool of CAs from the PE of T. diversifolia has an additional mechanism of action, and its anti-inflammatory effect was greater than what is described in the literature for this class of compounds using the same evaluation models. The similar chemical compositions observed for the infusion and the PE, contrasted with the different activities observed, suggests the presence of antagonist compounds produced during the extraction procedure (infusion); the infusion did not inhibit oedema, however it inhibited neutrophil migration. It suggests that although the great majority of plants present CAs, the category of anti-inflammatory effect of their extracts depends on a suitable pool of compounds and an absence of antagonists, among other factors.

CONCLUSIONS

CAs from T. diversifolia comprise a good pool of anti-inflammatory compounds with better activity mechanisms than NSAIDs, other active compounds from the leaf extracts (STLs and flavonoids) and CAs from other plant sources. Thus, the PE of T. diversifolia has high potential for the development of new anti-inflammatory phytomedicines. The infusion probably contains antagonists, and therefore it can be useful to treat inflammation processes where neutrophil recruitment is involved and oedema is not.

Differences between salivary and blood neutrophils from elderly and young denture wearers

We previously showed that neutrophils from patients with Candida-related denture stomatitis exhibited damaged function, and the advance in age intensified this condition. Because such alterations had been determined in elderly people that were not denture wearers, the purpose of this study was to clarify functional and phenotypic characteristics of neutrophils from elderly denture wearers (EDW) and young denture wearers (YDW) without oral lesion. We enrolled 20 denture wearers (12 EDW and 8 YDW) and determined the positivity of Candida species on maxillary prosthesis and palate. Additionally, blood and salivary neutrophils were evaluated. Furthermore, cytokines and chemokines salivary levels were detected. YDW presented higher positivity of Candida albicans than elderly ones. However, blood neutrophils from EDW expressed less CXCR1, CD62L and CD11b and had lower C. albicans phagocytosis than YDW. Although myeloperoxidase and elastase activity was significantly higher in C. albicans-stimulated blood neutrophils from elderly, they produced high levels of IL-10 and low levels of Granulocyte macrophage-colony stimulating factor (GM-CSF). Despite apoptosis rate of salivary neutrophils was enhanced, these cells were at a high number in YDW. GM-CSF and IL10 were lower in saliva from elderly group. These data confirmed that ageing affects blood and salivary neutrophils and could predispose elderly to persistent oral infections.

CCR5 mediates pro-osteoclastic and osteoclastogenic leukocyte chemoattraction

Periodontal disease (PD) progression involves the selective leukocyte infiltration into periodontium, supposedly mediated by the chemokine/chemokine receptor system. In this study, we investigated the role of chemokine receptor CCR5 in the immunoregulation of experimental PD in C57BL/6 (WT) and CCR5KO mice. Aggregatibacter actinomycetem comitans infection triggered the chemoattraction of distinct CCR5+ leukocyte subpopulations (determined by flow cytometry): CCR5+F4/80+ leukocytes, which co-express CD14 , CCR2, TNF-α, and IL-1β, indicative of activated macrophages; and CCR5+CD4+ cells, which co-express CXCR3, IFN-γ, and RANKL, indicative of Th1 lymphocytes, therefore comprising pro-osteoclastic and osteoclastogenic cell subsets, respectively. CCR5KO mice presented a lower PD severity (lower inflammation and alveolar bone loss) when compared with the WT strain, since the migration of F4/80+, TNF-α+, CD4+, and RANKL+ cells specifically decreased due to the lack of CCR5. Also, ELISA analysis demonstrated that the production of TNF-α, IL-1β, IL-6, IFN-γ, and RANKL in periodontal tissues was significantly decreased in the CCR5KO strain. The periodontal bacterial load and antimicrobial patterns were unaltered in CCR5KO mice. Our results demonstrate that the chemokine receptor is involved in the migration of distinct leukocyte subpopulations throughout experimental PD, being a potential target for therapeutic intervention in PD.

Absence of TLR2 influences survival of neutrophils after infection with Candida albicans

Candida albicans is an opportunistic pathogen, which causes local and/or disseminated diseases in immunosuppressed humans. Phagocytic cells play a critical role in the immune response against C. albicans. Toll like receptors (TLR) are important in the identification of invading microorganisms and in the regulation of neutrophil survival. TLR2 has been shown to participate in the response against pathogenic yeasts and to increase the functional life span of neutrophils. In view of these observations, we studied the involvement of TLR2 in neutrophil function after C. albicans infection. The absence of TLR2 resulted in lower chemotaxis of neutrophils to the site of infection. This in turn was associated with lower levels of chemokines from neutrophils, facilitating the dissemination of the pathogen to the lymph nodes and spleen. A high frequency of apoptotic neutrophils and macrophages in the inflammatory exudates from TLR2(-/-) mice was found. In addition, the phagocytic activity of neutrophils and macrophages, nitric oxide production and myeloperoxidase activity were diminished in cells from TLR2(-/-) mice. Together, these data demonstrate the importance of TLR2 signals for neutrophils activation and survival after C. albicans infection.

Patients with oral squamous cell carcinoma are characterized by increased frequency of suppressive regulatory T cells in the blood and tumor microenvironment

Oral squamous cell carcinoma (OSCC) is a cancerous lesion with high incidence worldwide. The immunoregulatory events leading to OSCC persistence remain to be elucidated. Our hypothesis is that regulatory T cells (Tregs) are important to obstruct antitumor immune responses in patients with OSCC. In the present study, we investigated the frequency, phenotype, and activity of Tregs from blood and lesions of patients with OSCC. Our data showed that >80% of CD4(+)CD25(+) T cells isolated from PBMC and tumor sites express FoxP3. Also, these cells express surface Treg markers, such as GITR, CD45RO, CD69, LAP, CTLA-4, CCR4, and IL-10. Purified CD4(+)CD25(+) T cells exhibited stronger suppressive activity inhibiting allogeneic T-cell proliferation and IFN-gamma production when compared with CD4(+)CD25(+) T cells isolated from healthy individuals. Interestingly, approximately 25% of CD4(+)CD25(-) T cells of PBMC from patients also expressed FoxP3 and, although these cells weakly suppress allogeneic T cells proliferative response, they inhibited IFN-gamma and induced IL-10 and TGF-beta secretion in these co-cultures. Thus, our data show that Treg cells are present in OSCC lesions and PBMC, and these cells appear to suppress immune responses both systemically and in the tumor microenvironment.

The essential role of toll like receptor-4 in the control of Aggregatibacter actinomycetemcomitans infection in mice

OBJECTIVE

Aggregatibacter actinomycetemcomitans is an oral Gram-negative bacterium that contributes to periodontitis progression. Isolated antigens from A. actinomycetemcomitans could be activating innate immune cells through Toll-like receptors (TLRs). In this study, we evaluated the role of TLR4 in the control of A. actinomycetemcomitans infection.

MATERIAL AND METHODS

We examined the mechanisms that modulate the outcome of A. actinomycetemcomitans-induced periodontal disease in TLR4(-/-) mice. The production of cytokines was evaluated by ELISA. The bacterial load was determined by counting the number of colony-forming units per gram of tissue.

RESULTS

The results showed that TLR4-deficient mice developed less severe periodontitis after A. actinomycetemcomitans infection, characterized by significantly lower bone loss and inflammatory cell migration to periodontal tissues. However, the absence of TLR4 facilitated the A. actinomycetemcomitans dissemination. Myeloperoxidase activity was diminished in the periodontal tissue of TLR4(-/-) mice. We observed a significant reduction in the production of tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta in the periodontal tissue of TLR4(-/-) mice.

CONCLUSION

The results of this study highlighted the role of TLR4 in controlling A. actinomycetemcomitans infection.

Absence of functional TLR4 impairs response of macrophages after Candida albicans infection

Candida albicans is recognized by phagocytic cells through a set of recognition receptors patterns. Recently, we showed the importance of TLR2 in the regulation of neutrophil survival after C. albicans infection. In the present work, we analyzed the involvement of TLR4 in the recognition of C. albicans by neutrophils and macrophages. Our results show that the absence of functional TLR4 resulted in lower chemotaxis of neutrophils to the site of infection, lower levels of TNF-α, CXCL1 and nitric oxide, and dissemination and persistence of the pathogen in lymph nodes and spleen. In vitro, the phagocytic activity, nitric oxide production and myeloperoxidase activity, CXCL1, IL-1β production by neutrophils from TLR4-defective mice were not changed. In contrast, macrophages from TLR4-defective mice demonstrated lower phagocytosis and lower levels of CXCL1, IL-1β and TNF-α. Together, these data demonstrate that TLR4 signals are important for the recognition of C. albicans by macrophages and their absence allows persistence of the infection.

Periodontitis and arthritis interaction in mice involves a shared hyper-inflammatory genotype and functional immunological interferences

Periodontitis (PD) and rheumatoid arthritis (RA) have been found to be clinically associated and to share the chronic nature of the inflammatory reaction associated with bone resorption activity. However, the mechanisms underlying such association are unknown. Therefore, we examined the basis of Actinobacillus actinomycetemcomitans- and Porphyromonas gingivalis-induced PD and pristane-induced arthritis (PIA) interaction in mice. Higher severity PD in the genetically inflammation prone acute inflammatory reactivity maximum (AIRmax) mice strain was associated with higher levels of TNF-alpha, IL-1beta, IL-17, matrix metalloproteinase (MMP)-13, and RANKL, whereas PD/PIA co-induction resulted in even higher levels of IL-1beta, IFN-gamma, IL-17, RANKL, and MMP-13 levels. Conversely, PD/PIA co-induction in AIRmin strain did not alter the course of both pathologies. PIA/PD co-induction resulted in altered expression of T-cell subsets transcription factors expression, with T-bet and RORgamma levels being upregulated, whereas GATA-3 levels were unaltered. Interestingly, PIA induction resulted in alveolar bone loss, such response being highly dependent on the presence of commensal oral bacteria. No differences were found in PIA severity parameters by PD co-induction. Our results show that the interaction between experimental PD and arthritis in mice involves a shared hyper-inflammatory genotype and functional interferences in innate and adaptive immune responses.

Association of human T lymphotropic virus 1 amplification of periodontitis severity with altered cytokine expression in response to a standard periodontopathogen infection

BACKGROUND

Periodontal diseases (PDs) are infectious diseases in which periodontopathogens trigger chronic inflammatory and immune responses that lead to tissue destruction. Recently, viruses have been implicated in the pathogenesis of PDs. Individuals infected with human T lymphotropic virus 1 (HTLV-1) present with abnormal oral health and a marked increased prevalence of periodontal disease.

METHODS

In this study, we investigated the patterns of periodontopathogen infection and local inflammatory immune markers in HTLV-1-seropositive individuals with chronic periodontitis (CP/HTLV-1 group) compared with HTLV-1-seronegative individuals with chronic periodontitis (CP group) and periodontally healthy, HTLV-1-seronegative individuals (control group).

RESULTS

Patients in the CP/HTLV-1 group had significantly higher values of bleeding on probing, mean probing depth, and attachment loss than patients in the CP group. The expression of tumor necrosis factor alpha and interleukin (IL) 4 was found to be similar in the CP and CP/HTLV-1 groups, whereas IL-12 and IL-17 levels trended toward a higher expression in the CP/HTLV-1 group. A significant increase was seen in the levels of IL-1beta and interferon gamma in the CP/HTLV-1 group compared with the CP group, whereas expression of the regulatory T cell marker FOXp3 and IL-10 was significantly decreased in the lesions from the CP/HTLV-1 group. Interestingly, similar frequency and/or load of periodontopathogens (Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Aggregatibacter actinomycetemcomitans) and frequency of viruses (herpes simplex virus 1, human cytomegalovirus, and Epstein-Barr virus) characteristically associated with PDs were found in the CP/HTLV and CP groups.

CONCLUSIONS

HTLV-1 may play a critical role in the pathogenesis of periodontal disease through the deregulation of the local cytokine network, resulting in an exacerbated response against a standard periodontopathogen infection.