Essential role of the CCL2-CCR2 axis in Mayaro virus-induced disease.

Mayaro virus (MAYV) is an emerging arbovirus member of the Togaviridae family and Alphavirus genus. MAYV infection causes an acute febrile illness accompanied by persistent polyarthralgia and myalgia. Understanding the mechanisms involved in arthritis caused by alphaviruses is necessary to develop specific therapies. In this work, we investigated the role of the CCL2/CCR2 axis in the pathogenesis of MAYV-induced disease. For this, wild-type (WT) C57BL/6J and CCR2-/- mice were infected with MAYV subcutaneously and evaluated for disease development. MAYV infection induced an acute inflammatory disease in WT mice. The immune response profile was characterized by an increase in the production of inflammatory mediators, such as IL-6, TNF, and CCL2. Higher levels of CCL2 at the local and systemic levels were followed by the significant recruitment of CCR2+ macrophages and a cellular response orchestrated by these cells. CCR2-/- mice showed an increase in CXCL-1 levels, followed by a replacement of the macrophage inflammatory infiltrate by neutrophils. Additionally, the absence of the CCR2 receptor protected mice from bone loss induced by MAYV. Accordingly, the silencing of CCL2 chemokine expression in vivo and the pharmacological blockade of CCR2 promoted a partial improvement in disease. Cell culture data support the mechanism underlying the bone pathology of MAYV, in which MAYV infection promotes a pro-osteoclastogenic microenvironment mediated by CCL2, IL-6, and TNF, which induces the migration and differentiation of osteoclast precursor cells. Overall, these data contribute to the understanding of the pathophysiology of MAYV infection and the identification future of specific therapeutic targets in MAYV-induced disease.IMPORTANCEThis work demonstrates the role of the CCL2/CCR2 axis in MAYV-induced disease. The infection of wild-type (WT) C57BL/6J and CCR2-/- mice was associated with high levels of CCL2, an important chemoattractant involved in the recruitment of macrophages, the main precursor of osteoclasts. In the absence of the CCR2 receptor, there is a mitigation of macrophage migration to the target organs of infection and protection of these mice against bone loss induced by MAYV infection. Much evidence has shown that host immune response factors contribute significantly to the tissue damage associated with alphavirus infections. Thus, this work highlights molecular and cellular targets involved in the pathogenesis of arthritis triggered by MAYV and identifies novel therapeutic possibilities directed to the host inflammatory response unleashed by MAYV.

The impact of arthritogenic viruses in oral tissues.

Arthritis and periodontitis are inflammatory diseases that share several immunopathogenic features. The expansion in the study of virus-induced arthritis has shed light on how this condition could impact other parts of the human body, including the mouth. Viral arthritis is an inflammatory joint disease caused by several viruses, most notably the alphaviruses Chikungunya virus (CHIKV), Sindbis virus (SINV), Ross River virus (RRV), Mayaro virus (MAYV), and O'nyong'nyong virus (ONNV). These viruses can induce an upsurge of matrix metalloproteinases and immune-inflammatory mediators such as Interleukin-6 (IL6), IL-1ß, tumor necrosis factor, chemokine ligand 2, and receptor activator of nuclear factor kappa-B ligand in the joint and serum of infected individuals. This can lead to the influx of inflammatory cells to the joints and associated muscles as well as osteoclast activation and differentiation, culminating in clinical signs of swelling, pain, and bone resorption. Moreover, several data indicate that these viral infections can affect other sites of the body, including the mouth. The human oral cavity is a rich and diverse microbial ecosystem, and viral infection can disrupt the balance of microbial species, causing local dysbiosis. Such events can result in oral mucosal damage and gingival bleeding, which are indicative of periodontitis. Additionally, infection by RRV, CHIKV, SINV, MAYV, or ONNV can trigger the formation of osteoclasts and upregulate pro-osteoclastogenic inflammatory mediators, interfering with osteoclast activation. As a result, these viruses may be linked to systemic conditions, including oral manifestations. Therefore, this review focuses on the involvement of alphavirus infections in joint and oral health, acting as potential agents associated with oral mucosal inflammation and alveolar bone loss. The findings of this review demonstrate how alphavirus infections could be linked to the comorbidity between arthritis and periodontitis and may provide a better understanding of potential therapeutic management for both conditions.

Tumour necrosis factor plays a deleterious role in the pathogenesis of chikungunya virus infection.

Arthralgia is a hallmark of chikungunya virus (CHIKV) infection and can be very debilitating and associated with a robust local inflammatory response. Many pathophysiological aspects associated with the disease remain to be elucidated. Here, we describe a novel model of CHIKV infection in immunocompetent mice and evaluate the role of tumour necrosis factor in the pathogenesis of the disease. C57BL/6 wild type (WT) or TNF receptor 1 deficient (TNFR1-/- ) mice were inoculated with 1 × 106 PFU of CHIKV in the paw. Alternatively, etanercept was used to inhibit TNF in infected WT mice. Hypernociception, inflammatory and virological analysis were performed. Inoculation of CHIKV into WT mice induced persistent hypernociception. There was significant viral replication in target organs and local production of inflammatory mediators in early time-points after infection. CHIKV infection was associated with specific humoral IgM and IgG responses. In TNFR1-/- mice, there was a decrease in the hypernociception threshold, which was associated with a milder local inflammatory response in the paw but delayed viral clearance. Local or systemic treatment with etanercept reduced CHIKV-induced hypernociception. This is the first study to describe hypernociception, a clinical correlation of arthralgia, in immunocompetent mice infected with CHIKV. It also demonstrates the dual role of TNF in contributing to viral clearance but driving tissue damage and hypernociception. Inhibition of TNF may have therapeutic benefits but its role in viral clearance suggests that viral levels must be monitored in CHIKV-infected patients and that TNF inhibitors should ideally be used in combination with anti-viral drugs.

TNF/iNOS/NO pathway mediates host susceptibility to endothelial-dependent circulatory failure and death induced by betacoronavirus infection.

Poor disease outcomes and lethality are directly related to endothelial dysfunction in betacoronavirus infections. Here, we investigated the mechanisms underlying the vascular dysfunction caused by the betacoronaviruses MHV-3 and SARS-CoV-2. Wild-type C57BL/6 (WT) and knockout mice for inducible nitric oxide synthase (iNOS-/-) or TNF receptor 1 (TNFR1-/-) were infected with MHV-3, and K18-hACE2 transgenic mice expressing human ACE2 were infected with SARS-CoV-2. Isometric tension was used to evaluate vascular function. Protein expression was determined by immunofluorescence. Tail-cuff plethysmography and Doppler were used to assess blood pressure and flow, respectively. Nitric oxide (NO) was quantified with the DAF probe. ELISA was used to assess cytokine production. Survival curves were estimated using Kaplan-Meier. MHV-3 infection reduced aortic and vena cava contractility, arterial blood pressure, and blood flow, resulting in death. Resistance mesenteric arteries showed increased contractility. The contractility of the aorta was normalized by removing the endothelium, inhibiting iNOS, genetically deleting iNOS, or scavenging NO. In the aorta, iNOS and phospho-NF-kB p65 subunit expression was enhanced, along with basal NO production. TNF production was increased in plasma and vascular tissue. Genetic deletion of TNFR1 prevented vascular changes triggered by MHV-3, and death. Basal NO production and iNOS expression were also increased by SARS-CoV-2. In conclusion, betacoronavirus induces an endothelium-dependent decrease in contractility in macro-arteries and veins, leading to circulatory failure and death via TNF/iNOS/NO. These data highlight the key role of the vascular endothelium and TNF in the pathogenesis and lethality of coronaviruses.

Blocking the HGF-MET pathway induces resolution of neutrophilic inflammation by promoting neutrophil apoptosis and efferocytosis.

Inflammation resolution is an active process that involves cellular events such as apoptosis and efferocytosis, which are key steps in the restoration of tissue homeostasis. Hepatocyte growth factor (HGF) is a growth factor mostly produced by mesenchymal-origin cells and has been described to act via MET receptor tyrosine kinase. The HGF/MET axis is essential for determining the progression and severity of inflammatory and immune-mediated disorders. Here, we investigated the effect of blocking the HGF/MET signalling pathway by PF-04217903 on the resolution of established models of neutrophilic inflammation. In a self-resolving model of gout induced by MSU crystals, HGF expression on periarticular tissue peaked at 12 h, the same time point that neutrophils reach their maximal accumulation in the joints. The HGF/MET axis was activated in this model, as demonstrated by increased levels of MET phosphorylation in neutrophils (Ly6G+ cells). In addition, the number of neutrophils was reduced in the knee exudate after PF-04217903 treatment, an effect accompanied by increased neutrophil apoptosis and efferocytosis and enhanced expression of Annexin A1, a key molecule for inflammation resolution. Reduced MPO activity, IL-1ß and CXCL1 levels were also observed in periarticular tissue. Importantly, PF-04217903 reduced the histopathological score and hypernociceptive response. Similar findings were obtained in LPS-induced neutrophilic pleurisy. In human neutrophils, the combined use of LPS and HGF increased MET phosphorylation and provided a prosurvival signal, whereas blocking MET with PF-04217903 induced caspase-dependent neutrophil apoptosis. Taken together, these data demonstrate that blocking HGF/MET signalling may be a potential therapeutic strategy for inducing the resolution of neutrophilic inflammatory responses.

SOCS2 regulates alveolar bone loss in Aggregatibacter actinomycetemcomitans-induced periodontal disease.

INTRODUCTION: The role of suppressor of cytokine signaling 2 (SOCS2) in Aggregatibacter actinomycetemcomitans (Aa)-induced alveolar bone loss is unknown; thus, it was investigated in this study. METHODS: Alveolar bone loss was induced by infecting C57BL/6 wild-type (WT) and Socs2-knockout (Socs2-/-) mice with Aa. Bone parameters, bone loss, bone cell counts, the expression of bone remodeling markers, and cytokine profile were evaluated by microtomography, histology, qPCR, and/or ELISA. Bone marrow cells (BMC) from WT and Socs2-/- mice were differentiated in osteoblasts or osteoclasts for analysis of the expression of specific markers. RESULTS: Socs2-/- mice intrinsically exhibited irregular phenotypes in the maxillary bone and an increased number of osteoclasts. Upon Aa infection, SOCS2 deficiency resulted in the increased alveolar bone loss, despite decreased proinflammatory cytokine production, in comparison to the WT mice. In vitro, SOCS2 deficiency resulted in the increased osteoclasts formation, decreased expression of bone remodeling markers, and proinflammatory cytokines after Aa-LPS stimulus. CONCLUSIONS: Collectively, data suggest that SOCS2 is a regulator of Aa-induced alveolar bone loss by controlling the differentiation and activity of bone cells, and proinflammatory cytokines availability in the periodontal microenvironment and an important target for new therapeutic strategies. Thus, it can be helpful in preventing alveolar bone loss in periodontal inflammatory conditions.

A suitable model to investigate acute neurological consequences of coronavirus infection.

OBJECTIVE AND DESIGN: The present study aimed to investigate the neurochemical and behavioral effects of the acute consequences after coronavirus infection through a murine model. MATERIAL: Wild-type C57BL/6 mice were infected intranasally (i.n) with the murine coronavirus 3 (MHV-3). METHODS: Mice underwent behavioral tests. Euthanasia was performed on the fifth day after infection (5 dpi), and the brain tissue was subjected to plaque assays for viral titration, ELISA, histopathological, immunohistochemical and synaptosome analysis. RESULTS: Increased viral titers and mild histological changes, including signs of neuronal degeneration, were observed in the cerebral cortex of infected mice. Importantly, MHV-3 infection induced an increase in cortical levels of glutamate and calcium, which is indicative of excitotoxicity, as well as increased levels of pro-inflammatory cytokines (IL-6, IFN-γ) and reduced levels of neuroprotective mediators (BDNF and CX3CL1) in the mice brain. Finally, behavioral analysis showed impaired motor, anhedonia-like and anxiety-like behaviors in animals infected with MHV-3. CONCLUSIONS: In conclusion, the data presented emulate many aspects of the acute neurological outcomes seen in patients with COVID-19. Therefore, this model may provide a preclinical platform to study acute neurological sequelae induced by coronavirus infection and test possible therapies.

Fcγ RIIb protects from reperfusion injury by controlling antibody and type I IFN-mediated tissue injury and death.

Intestinal ischemia and reperfusion (I/R) is accompanied by an exacerbated inflammatory response characterized by deposition of IgG, release of inflammatory mediators, and intense neutrophil influx in the small intestine, resulting in severe tissue injury and death. We hypothesized that Fcγ RIIb activation by deposited IgG could inhibit tissue damage during I/R. Our results showed that I/R induction led to the deposition of IgG in intestinal tissue during the reperfusion phase. Death upon I/R occurred earlier and was more frequent in Fcγ RIIb-/- than WT mice. The higher lethality rate was associated with greater tissue injury and bacterial translocation to other organs. Fcγ RIIb-/- mice presented changes in the amount and repertoire of circulating IgG, leading to increased IgG deposition in intestinal tissue upon reperfusion in these mice. Depletion of intestinal microbiota prevented antibody deposition and tissue damage in Fcγ RIIb-/- mice submitted to I/R. We also observed increased production of ROS on neutrophils harvested from the intestines of Fcγ RIIb-/- mice submitted to I/R. In contrast, Fcγ RIII-/- mice presented reduced tissue damage and neutrophil influx after reperfusion injury, a phenotype reversed by Fcγ RIIb blockade. In addition, we observed reduced IFN-ß expression in the intestines of Fcγ RIII-/- mice after I/R, a phenotype that was also reverted by blocking Fcγ RIIb. IFNAR-/- mice submitted to I/R presented reduced lethality and TNF release. Altogether our results demonstrate that antibody deposition triggers Fcγ RIIb to control IFN-ß and IFNAR activation and subsequent TNF release, tailoring tissue damage, and death induced by reperfusion injury.

A Biosafety Level 2 Mouse Model for Studying Betacoronavirus-Induced Acute Lung Damage and Systemic Manifestations.

The emergence of life-threatening zoonotic diseases caused by betacoronaviruses, including the ongoing coronavirus disease 19 (COVID-19) pandemic, has highlighted the need for developing preclinical models mirroring respiratory and systemic pathophysiological manifestations seen in infected humans. Here, we showed that C57BL/6J wild-type mice intranasally inoculated with the murine betacoronavirus murine hepatitis coronavirus 3 (MHV-3) develop a robust inflammatory response leading to acute lung injuries, including alveolar edema, hemorrhage, and fibrin thrombi. Although such histopathological changes seemed to resolve as the infection advanced, they efficiently impaired respiratory function, as the infected mice displayed restricted lung distention and increased respiratory frequency and ventilation. Following respiratory manifestation, the MHV-3 infection became systemic, and a high virus burden could be detected in multiple organs along with morphological changes. The systemic manifestation of MHV-3 infection was also marked by a sharp drop in the number of circulating platelets and lymphocytes, besides the augmented concentration of the proinflammatory cytokines interleukin 1 beta (IL-1ß), IL-6, IL-12, gamma interferon (IFN-γ), and tumor necrosis factor (TNF), thereby mirroring some clinical features observed in moderate and severe cases of COVID-19. Importantly, both respiratory and systemic changes triggered by MHV-3 infection were greatly prevented by blocking TNF signaling, either via genetic or pharmacologic approaches. In line with this, TNF blockage also diminished the infection-mediated release of proinflammatory cytokines and virus replication of human epithelial lung cells infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Collectively, results show that MHV-3 respiratory infection leads to a large range of clinical manifestations in mice and may constitute an attractive, lower-cost, biosafety level 2 (BSL2) in vivo platform for evaluating the respiratory and multiorgan involvement of betacoronavirus infections. IMPORTANCE Mouse models have long been used as valuable in vivo platforms to investigate the pathogenesis of viral infections and effective countermeasures. The natural resistance of mice to the novel betacoronavirus SARS-CoV-2, the causative agent of COVID-19, has launched a race toward the characterization of SARS-CoV-2 infection in other animals (e.g., hamsters, cats, ferrets, bats, and monkeys), as well as adaptation of the mouse model, by modifying either the host or the virus. In the present study, we utilized a natural pathogen of mice, MHV, as a prototype to model betacoronavirus-induced acute lung injure and multiorgan involvement under biosafety level 2 conditions. We showed that C57BL/6J mice intranasally inoculated with MHV-3 develops severe disease, which includes acute lung damage and respiratory distress that precede systemic inflammation and death. Accordingly, the proposed animal model may provide a useful tool for studies regarding betacoronavirus respiratory infection and related diseases.

cis-Aconitic Acid, a Constituent of Echinodorus grandiflorus Leaves, Inhibits Antigen-Induced Arthritis and Gout in Mice.

cis-Aconitic acid is a constituent from the leaves of Echinodorus grandiflorus, a medicinal plant traditionally used in Brazil to treat inflammatory conditions, including arthritic diseases. The present study aimed to investigate the anti-arthritic effect of cis-aconitic acid in murine models of antigen-induced arthritis and monosodium urate-induced gout. The possible underlying mechanisms of action was evaluated in THP-1 macrophages. Oral treatment with cis-aconitic acid (10, 30, and 90 mg/kg) reduced leukocyte accumulation in the joint cavity and C-X-C motif chemokine ligand 1 and IL-1ß levels in periarticular tissue. cis-Aconitic acid treatment reduced joint inflammation in tissue sections of antigen-induced arthritis mice and these effects were associated with decreased mechanical hypernociception. Administration of cis-aconitic acid (30 mg/kg p. o.) also reduced leukocyte accumulation in the joint cavity after the injection of monosodium urate crystals. cis-Aconitic acid reduced in vitro the release of TNF-α and phosphorylation of IκBα in lipopolysaccharide-stimulated THP-1 macrophages, suggesting that inhibition of nuclear factor kappa B activation was an underlying mechanism of cis-aconitic acid-induced anti-inflammatory effects. In conclusion, cis-aconitic acid has significant anti-inflammatory effects in antigen-induced arthritis and monosodium urate-induced arthritis in mice, suggesting its potential for the treatment of inflammatory diseases of the joint in humans. Additionally, our findings suggest that this compound may contribute to the anti-inflammatory effect previously reported for E. grandiflorus extracts.

Absence of CCR2 Promotes Proliferation of Alveolar Macrophages That Control Lung Inflammation in Acute Respiratory Distress Syndrome in Mice.

Acute respiratory distress syndrome (ARDS) consists of uncontrolled inflammation that causes hypoxemia and reduced lung compliance. Since it is a complex process, not all details have been elucidated yet. In a well-controlled experimental murine model of lipopolysaccharide (LPS)-induced ARDS, the activity and viability of macrophages and neutrophils dictate the beginning and end phases of lung inflammation. C-C chemokine receptor type 2 (CCR2) is a critical chemokine receptor that mediates monocyte/macrophage activation and recruitment to the tissues. Here, we used CCR2-deficient mice to explore mechanisms that control lung inflammation in LPS-induced ARDS. CCR2-/- mice presented higher total numbers of pulmonary leukocytes at the peak of inflammation as compared to CCR2+/+ mice, mainly by enhanced influx of neutrophils, whereas we observed two to six-fold lower monocyte or interstitial macrophage numbers in the CCR2-/-. Nevertheless, the time needed to control the inflammation was comparable between CCR2+/+ and CCR2-/-. Interestingly, CCR2-/- mice presented higher numbers and increased proliferative rates of alveolar macrophages from day 3, with a more pronounced M2 profile, associated with transforming growth factor (TGF)-ß and C-C chemokine ligand (CCL)22 production, decreased inducible nitric oxide synthase (Nos2), interleukin (IL)-1ß and IL-12b mRNA expression and increased mannose receptor type 1 (Mrc1) mRNA and CD206 protein expression. Depletion of alveolar macrophages significantly delayed recovery from the inflammatory insult. Thus, our work shows that the lower number of infiltrating monocytes in CCR2-/- is partially compensated by increased proliferation of resident alveolar macrophages during the inflammation control of experimental ARDS.

Effect of the Hydroethanolic Extract from Echinodorus grandiflorus Leaves and a Fraction Enriched in Flavone-C-Glycosides on Antigen-Induced Arthritis in Mice.

The leaves of Echinodorus grandiflorus are traditionally used in Brazil to treat several inflammatory conditions, including arthritis. This study aimed to investigate the antiarthritis activity of the 70% ethanol extract of E. grandiflorus leaves and a standardized flavonoid-rich fraction in an antigen-induced arthritis model in mice. Previously immunized mice were treated per os with saline (control group), 70% ethanol extract (100-1000 mg/kg), or a flavonoid-rich fraction (0.7-7.2 mg/kg) 40 minutes before and 3 and 6 hours after the challenge with antigen into the knee joint. The administration of the 70% ethanol extract and flavonoid-rich fraction to mice significantly reduced neutrophil recruitment to the joint cavity and in periarticular tissue. The levels of chemokine (C-X-C motif) ligand 1, tumor necrosis factor-α, and interleukin-1ß quantified by the enzyme-linked immunosorbent assay (ELISA) in the periarticular tissue were also diminished in mice treated with the 70% ethanol extract and flavonoid-rich fraction, as well as mechanical hypernociception. Histological analysis confirmed that both the 70% ethanol extract and flavonoid-rich fraction suppressed joint inflammation and inhibited cartilage and bone destruction when compared to the control group. Our results demonstrate, for the first time, that E. grandiflorus has anti-inflammatory activity in an experimental arthritis model and highlights the role of flavonoids in the observed response.

Evaluation of carbon nanotubes functionalized with sodium hyaluronate in the inflammatory processes for oral regenerative medicine applications.

OBJECTIVES: The objectives of this study were to assess the effects of hyaluronic acid (HY), multi-walled carbon nanotubes (MWCNT), and MWCNT functionalized with HY (HY-MWCNT) on the resolution of neutrophilic inflammation in the pleural cavity of LPS-challenged mice and to assess the influence of these materials in the inflammatory process of bone repair of tooth sockets of rats. MATERIALS AND METHODS: C57Bl/6 mice were intra-pleurally injected with HY, MWCNT, HY-MWCNT, phosphate-buffered saline (PBS), or LPS. The animals were euthanized after 8 and 24 h, and cells were harvested for total and differential cell counting. The tooth sockets of Wistar rats were filled with HY, MWCNT, HY-MWCNT, or blood clot (control). After 1, 3, and 7 days, histological and morphometric analyses evaluated the number of cell nuclei and blood vessels, and bone trabeculae formation in the sockets. Myeloperoxidase (MPO) activity quantified neutrophil accumulation in the sockets. RESULTS: HY, MWCNT, and HY-MWCNT increased neutrophilic recruitment at 8 h and reduced the inflammatory process at 24 h in the pleural cavity. Histological and morphometric analyses and MPO activity showed no significant differences in the recruitment of inflammatory cells in the tooth sockets. HY increased the number of blood vessels, and HY and HY-MWCNT increased bone trabeculae formation at 7 days of tooth extraction. CONCLUSIONS: HY, MWCNT, and HY-MWCNT resolved the neutrophilic inflammation in the pleural cavity of the mice. However, these materials did not modulate the inflammatory process in the early stages of bone repair of the tooth sockets, thereby excluding this action as a possible mechanism by which these biomaterials accelerate bone repair. CLINICAL RELEVANCE: HY-MWCNT is capable of accelerating bone repair/regeneration without affecting the inflammatory phase during the bone healing process.

Arthritis-induced alveolar bone loss is associated with changes in the composition of oral microbiota.

Rheumatoid arthritis (RA) and periodontitis (PD) are chronic inflammatory disorders that cause bone loss. PD tends to be more prevalent and severe in RA patients. Previous experimental studies demonstrated that RA triggers alveolar bone loss similarly to PD. The aim of this study was to investigate if arthritis-induced alveolar bone loss is associated with modification in the oral microbiota. Checkerboard DNA-DNA hybridization was employed to analyze forty oral bacterial species in 3 groups of C57BL/6 mice: control (n = 12; without any challenge); Y4 (n = 8; received oral inoculation of Aggregatibacter Actinomycetemcomitans strain FDC Y4) and AIA group (n = 12; chronic antigen-induced arthritis). The results showed that AIA and Y4 group exhibited similar patterns of bone loss. The AIA group exhibited higher counts of most bacterial species analyzed with predominance of Gram-negative species similarly to infection-induced PD. Prevotella nigrescens and Treponema denticola were detected only in the Y4 group whereas Campylobacter showae, Streptococcus mitis and Streptococcus oralis were only found in the AIA group. Counts of Parvimonas micra, Selenomonas Noxia and Veillonella parvula were greater in the AIA group whereas Actinomyces viscosus and Neisseira mucosa were in large proportion in Y4 group. In conclusion, AIA is associated with changes in the composition of the oral microbiota, which might account for the alveolar bone loss observed in AIA mice.

Effects of angiotensin II type I receptor blocker losartan on orthodontic tooth movement.

INTRODUCTION: Drugs that block the renin-angiotensin system (RAS) are widely used for treating hypertension, heart and kidney failure, and the harmful effects of diabetes. Components of the RAS have been identified in various organs, but little is known of their effects on bone remodeling. The aim of this study was to evaluate whether the blockage of the RAS influences strain-induced bone remodeling in a model of orthodontic tooth movement. METHODS: An orthodontic appliance was placed in C57BL6/J mice that were randomly divided into 2 groups: vehicle-treated mice (VH) and mice treated with losartan (an angiotensin II receptor blocker). Orthodontic tooth movement and the number of tartrate-resistant acid phosphatase-positive cells were determined by histopathologic analysis. The expression of mediators involved in bone remodeling was evaluated by quantitative real-time polymerase chain reaction. Blood pressure was measured before and during the experimental period. RESULTS: Orthodontic tooth movement and tartrate-resistant acid phosphatase-positive cells were significantly reduced in the losartan group compared with the VH group. mRNA levels of osteoclast markers (RANK, RANKL, cathepsin K, and metalloproteinase 13) were lower in the losartan mice than in the VH group, whereas the expressions of osteoblast markers and negative regulators of bone resorption (periostin, dentin matrix protein, alkaline phosphatase, collagen 1A1, semaphorin 3A3, metalloproteinase 2, and osteoprotegerin) were higher in the VH group. CONCLUSIONS: Blockage of the RAS system decreases osteoclast differentiation and activity and, consequently, results in decreased strain-induced bone remodeling in orthodontic tooth movement.

Effect of low-level laser therapy on inflammatory mediator release during chemotherapy-induced oral mucositis: a randomized preliminary study.

Patients undergoing hematopoietic stem cell transplantation (HSCT) are submitted to a conditioning regimen of high-dose chemotherapy, with or without radiation therapy, which usually results in oral ulcerations and mucosal barrier breakdown. Oral mucositis (OM) is a common and debilitating toxicity side effect of autologous and allogeneic HSCT. The aim of this study was to evaluate the effect of low-level laser therapy (LLLT) on the severity of OM and inflammatory mediator (TNF-α, IL-6, IL-1ß, IL-10, TGF-ß, metalloproteinases, and growth factors) levels in saliva and blood of HSCT patients. Thirty patients were randomly assigned to two groups: control (n = 15) and laser (n = 15). LLLT was applied from the first day of the conditioning regimen until day 7 post-HSCT (D + 7). Saliva and blood were collected from patients on admission (AD), D-1, D + 3, D + 7, and on marrow engraftment day (ME). Clinical results showed less severe OM in the laser group (p < 0.05). The LLLT group showed increased matrix metalloproteinase 2 (MMP-2) levels in saliva on D + 7 (p = 0.04). Significant differences were also observed for IL-10 on D + 7 and on ME in blood plasma, when compared to the control group (p < 0.05). No significant differences were seen in saliva or blood for the other inflammatory mediators investigated. LLLT was clinically effective in reducing the severity of chemotherapy-induced OM in HSCT patients, and its mechanism of action does not seem to be completely linked to the modulation of pro- or anti-inflammatory cytokines, growth factors or matrix metalloproteinases.

Brain-derived neurotrophic factor in chronic periodontitis.

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophic factor family. Outside the nervous system, BDNF has been shown to be expressed in various nonneural tissues, such as periodontal ligament, dental pulp, and odontoblasts. Although a role for BDNF in periodontal regeneration has been suggested, a function for BDNF in periodontal disease has not yet been studied. The aim of this study was to analyze the BDNF levels in periodontal tissues of patients with chronic periodontitis (CP) and periodontally healthy controls (HC). All subjects were genotyped for the rs4923463 and rs6265 BDNF polymorphisms. Periodontal tissues were collected for ELISA, myeloperoxidase (MPO), and microscopic analysis from 28 CP patients and 29 HC subjects. BDNF levels were increased in CP patients compared to HC subjects. A negative correlation was observed when analyzing concentration of BDNF and IL-10 in inflamed periodontium. No differences in frequencies of BDNF genotypes between CP and HC subjects were observed. However, BDNF genotype GG was associated with increased levels of BDNF, TNF-α, and CXCL10 in CP patients. In conclusion, BDNF seems to be associated with periodontal disease process, but the specific role of BDNF still needs to be clarified.

The glycosaminoglycan-binding chemokine fragment CXCL9(74-103) reduces inflammation and tissue damage in mouse models of coronavirus infection.

Introduction: Pulmonary diseases represent a significant burden to patients and the healthcare system and are one of the leading causes of mortality worldwide. Particularly, the COVID-19 pandemic has had a profound global impact, affecting public health, economies, and daily life. While the peak of the crisis has subsided, the global number of reported COVID-19 cases remains significantly high, according to medical agencies around the world. Furthermore, despite the success of vaccines in reducing the number of deaths caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there remains a gap in the treatment of the disease, especially in addressing uncontrolled inflammation. The massive recruitment of leukocytes to lung tissue and alveoli is a hallmark factor in COVID-19, being essential for effectively responding to the pulmonary insult but also linked to inflammation and lung damage. In this context, mice models are a crucial tool, offering valuable insights into both the pathogenesis of the disease and potential therapeutic approaches. Methods: Here, we investigated the anti-inflammatory effect of the glycosaminoglycan (GAG)-binding chemokine fragment CXCL9(74-103), a molecule that potentially decreases neutrophil transmigration by competing with chemokines for GAG-binding sites, in two models of pneumonia caused by coronavirus infection. Results: In a murine model of betacoronavirus MHV-3 infection, the treatment with CXCL9(74-103) decreased the accumulation of total leukocytes, mainly neutrophils, to the alveolar space and improved several parameters of lung dysfunction 3 days after infection. Additionally, this treatment also reduced the lung damage. In the SARS-CoV-2 model in K18-hACE2-mice, CXCL9(74-103) significantly improved the clinical manifestations of the disease, reducing pulmonary damage and decreasing viral titers in the lungs. Discussion: These findings indicate that CXCL9(74-103) resulted in highly favorable outcomes in controlling pneumonia caused by coronavirus, as it effectively diminishes the clinical consequences of the infections and reduces both local and systemic inflammation.

Annexin A1 improves immune responses and control of tissue parasitism during Leishmania amazonensis infection in BALB/c mice.

Leishmaniases, a group of diseases caused by the species of the protozoan parasite Leishmania, remains a significant public health concern worldwide. Host immune responses play a crucial role in the outcome of Leishmania infections, and several mediators that regulate inflammatory responses are potential targets for therapeutic approaches. Annexin A1 (AnxA1), an endogenous protein endowed with anti-inflammatory and pro-resolving properties, has emerged as a potential player. We have shown that during L. braziliensis infection, deficiency of AnxA1 exacerbates inflammatory responses but does not affect parasite burden. Here, we have investigated the role of AnxA1 in L. amazonensis infection, given the non-healing and progressive lesions characteristic of this infectious model. Infection of AnxA1 KO BALB/c mice resulted in increased lesion size and tissue damage associated with higher parasite burdens and enhanced inflammatory response. Notably, therapeutic application of the AnxA1 peptidomimetic Ac2-26 improves control of parasite replication and increases IL-10 production in vivo and in vitro, in both WT and AnxA1 KO mice. Conversely, administration of WRW4, an inhibitor of FPR2/3, resulted in larger lesions and decreased production of IL-10, suggesting that the effects of AnxA1 during L. amazonensis infection are associated with the engagement of these receptors. Our study illuminates the role of AnxA1 in L. amazonensis infection, demonstrating its impact on the susceptibility phenotype of BALB/c mice. Furthermore, our results indicate that targeting the AnxA1 pathway by using the Ac2-26 peptide could represent a promising alternative for new treatments for leishmaniasis.

Effect of photobiomodulation on inflammatory cytokines produced by HaCaT keratinocytes.

Objective: to evaluate the effects of the red and near-infrared wavelength lasers in isolated and simultaneous way on the modulation of inflammatory cytokines produced by human keratinocytes (HaCaT) challenged by cytokines of human monocytes stimulated by lipopolysaccharide from Escherichia coli. Design: HaCaT cells was previously exposed to the laser with wavelengths red (660 nm), near-infrared (808 nm). Then, HaCat cells were stimulated with the supernatant of lipopolysaccharide-challenged peripheral blood cells. The cytokines expressed by HaCat cells were measured using multiplex CBA assay. Results: HaCaT cells increased the production of inflammatory cytokines when stimulated with infrared laser compared to the control group (IFN-α2, IFN-γ, TNF-α, MCP-1, IL-6, IL-8, IL-10, IL -12p70, IL -17A, IL-23, IL-33), the red laser group (IFN-γ and IL-23) and the group of two lasers used simultaneously (IFN-α2, IFN-γ, IL-6 and IL-8, IL-17A, IL-18 and IL-23) (p < 0.05). The red laser also stimulated an increase in the expression of IFN-α2 by HaCaT cells in relation to the control group (p < 0.05). Conclusion: Infrared laser, with an energy density of 5 J/cm2, appear to be able to modulate inflammatory cytokines produced by HaCaT cells challenged by human monocyte cytokines.