Porphyromonas gingivalis gingipains cause defective macrophage migration towards apoptotic cells and inhibit phagocytosis of primary apoptotic neutrophils

Colorimetric sensing for translational applications: from colorants to mechanisms

Colorimetric sensing offers instant reporting via visible signals. Versus labor-intensive and instrument-dependent detection methods, colorimetric sensors present advantages including short acquisition time, high throughput screening, low cost, portability, and a user-friendly approach. These advantages have driven substantial growth in colorimetric sensors, particularly in point-of-care (POC) diagnostics. Rapid progress in nanotechnology, materials science, microfluidics technology, biomarker discovery, digital technology, and signal pattern analysis has led to a variety of colorimetric reagents and detection mechanisms, which are fundamental to advance colorimetric sensing applications. This review first summarizes the basic components (e.g., color reagents, recognition interactions, and sampling procedures) in the design of a colorimetric sensing system. It then presents the rationale design and typical examples of POC devices, e.g., lateral flow devices, microfluidic paper-based analytical devices, and wearable sensing devices. Two highlighted colorimetric formats are discussed: combinational and activatable systems based on the sensor-array and lock-and-key mechanisms, respectively. Case discussions in colorimetric assays are organized by the analyte identities. Finally, the review presents challenges and perspectives for the design and development of colorimetric detection schemes as well as applications. The goal of this review is to provide a foundational resource for developing colorimetric systems and underscoring the colorants and mechanisms that facilitate the continuing evolution of POC sensors.

Periodontal pathogens and cancer development

Increasing evidence suggests a significant association between periodontal disease and the occurrence of various cancers. The carcinogenic potential of several periodontal pathogens has been substantiated in vitro and in vivo. This review provides a comprehensive overview of the diverse mechanisms employed by different periodontal pathogens in the development of cancer. These mechanisms induce chronic inflammation, inhibit the host's immune system, activate cell invasion and proliferation, possess anti-apoptotic activity, and produce carcinogenic substances. Elucidating these mechanisms might provide new insights for developing novel approaches for tumor prevention, therapeutic purposes, and survival improvement.

Sialidase facilitates Porphyromonas gingivalis immune evasion by reducing M1 polarization, antigen presentation, and phagocytosis of infected macrophages

Background

Porphyromonas gingivalis (P. gingivalis), a major pathogen of periodontitis, can evade host immune defenses. Previously, we found that P. gingivalis W83 sialidase gene mutant strain (ΔPG0352) was more easily cleared by macrophages. The aims of this study were to investigate the effects of sialidase in P. gingivalis on the polarization, antigen presentation, and phagocytosis of infected macrophages and to clarify the mechanism of P. gingivalis immune evasion.

Methods

Human monocytes U937 were differentiated to macrophages and infected with P. gingivalis W83, ΔPG0352, comΔPG0352, and Escherichia coli (E. coli). The phagocytosis of macrophages was observed by transmission electron microscopy and flow cytometry. ELISA or Griess reaction were used to examine the levels of interleukin-12 (IL-12), inducible nitric oxide synthase (iNOS) and interleukin-10 (IL-10), and the expressions of CD68, CD80 and CD206 were determined by flow cytometry. The expression of major histocompatibility complex-II (MHC-II) was detected by immunofluorescence. A rat periodontitis model was established to determine the M1 and M2 polarization of macrophages.

Results

Compare with P. gingivalis W83, ΔPG0352 increased the levels of IL-12, iNOS, CD80, and MHC-II and inhibited the levels of IL-10 and CD206. Macrophages phagocytosed 75.4% of ΔPG0352 and 59.5% of P. gingivalis W83. In the rat periodontitis model, the levels of M1 and M2 macrophages in P. gingivalis W83 group were both higher than those in ΔPG0352 group, while the ratio of M1/M2 was higher in the ΔPG0352 group. Alveolar bone absorption was lower in ΔPG0352 group.

Conclusion

Sialidase facilitates P. gingivalis immune evasion by reducing M1 polarization, antigen presentation, and phagocytosis of infected macrophages.

Porphyromonas gingivalis regulates atherosclerosis through an immune pathway

Atherosclerosis (AS) is a chronic inflammatory disease, involving a pathological process of endothelial dysfunction, lipid deposition, plaque rupture, and arterial occlusion, and is one of the leading causes of death in the world population. The progression of AS is closely associated with several inflammatory diseases, among which periodontitis has been shown to increase the risk of AS. Porphyromonas gingivalis (P. gingivalis), presenting in large numbers in subgingival plaque biofilms, is the “dominant flora” in periodontitis, and its multiple virulence factors are important in stimulating host immunity. Therefore, it is significant to elucidate the potential mechanism and association between P. gingivalis and AS to prevent and treat AS. By summarizing the existing studies, we found that P. gingivalis promotes the progression of AS through multiple immune pathways. P. gingivalis can escape host immune clearance and, in various forms, circulate with blood and lymph and colonize arterial vessel walls, directly inducing local inflammation in blood vessels. It also induces the production of systemic inflammatory mediators and autoimmune antibodies, disrupts the serum lipid profile, and thus promotes the progression of AS. In this paper, we summarize the recent evidence (including clinical studies and animal studies) on the correlation between P. gingivalis and AS, and describe the specific immune mechanisms by which P. gingivalis promotes AS progression from three aspects (immune escape, blood circulation, and lymphatic circulation), providing new insights into the prevention and treatment of AS by suppressing periodontal pathogenic bacteria.

PD-1/PD-L1 pathway: A double-edged sword in periodontitis

Periodontitis is a disease caused by infection and immunological imbalance, which often leads to the destruction of periodontal tissue. Programmed death protein 1 (PD-1) and its ligand: programmed death ligand 1 (PD-L1) are important "immune checkpoint" proteins that have a negative regulatory effect on T cells and are targets of immunotherapy. Studies have shown that the expression of PD-1 and PD-L1 in patients with periodontitis is higher than that in healthy individuals. The keystone pathogen Porphyromonas gingivalis (P. gingivalis) is believed to be the main factor driving the upregulation of PD-1/PD-L1. High expression of PD-1/PD-L1 can inhibit the inflammatory response and reduce the destruction of periodontal supporting tissues, but conversely, it can promote the "immune escape" of P. gingivalis, thus magnifying infections. In addition, the PD-1/PD-L1 pathway is also associated with various diseases, such as cancer and Alzheimer's disease. In this review, we discuss the influence and mechanism of the PD-1/PD-L1 pathway as a "double-edged sword" affecting the occurrence and development of periodontitis, as well as its function in periodontitis-related systemic disorders. The PD-1/PD-L1 pathway could be a new avenue for periodontal and its related systemic disorders therapy.

COR388 (atuzaginstat): an investigational gingipain inhibitor for the treatment of Alzheimer disease

INTRODUCTION

Evidence from in vitro and in vivo studies demonstrates that amyloid beta (Aβ) oligomers have potent, broad-spectrum antimicrobial properties created by fibrils that entrap pathogens and disrupt their membranes. Data suggest that Aβ may play a protective role in the innate immune response to microbial infections and that Aβ in the brain plays a damaging role when the inflammatory response is not well controlled.

AREAS COVERED

This paper describes the relationship between periodontal disease and Alzheimer disease (AD), the role of Porphyromonas gingivalis and its secreted gingipains in AD, and the potential of the gingipain inhibitor atuzaginstat (COR388) to modulate AD neuropathologies.

EXPERT OPINION

P. gingivalis is opsonized by Aβ42, is capable of entering the brain, and is an accelerant of neuropathologies in rodent models of AD. Thus, in our opinion, this bacteria is highly likely to be a pathogen capable of initiating or precipitating the progression of AD, which agrees with the pathogen hypothesis of clinical AD development.

Targeting the succinate receptor effectively inhibits periodontitis

Periodontal disease (PD) is one of the most common inflammatory diseases in humans and is initiated by an oral microbial dysbiosis that stimulates inflammation and bone loss. Here, we report an abnormal elevation of succinate in the subgingival plaque of subjects with severe PD. Succinate activates succinate receptor-1 (SUCNR1) and stimulates inflammation. We detected SUCNR1 expression in the human and mouse periodontium and hypothesize that succinate activates SUCNR1 to accelerate periodontitis through the inflammatory response. Administration of exogenous succinate enhanced periodontal disease, whereas SUCNR1 knockout mice were protected from inflammation, oral dysbiosis, and subsequent periodontal bone loss in two different models of periodontitis. Therapeutic studies demonstrated that a SUCNR1 antagonist inhibited inflammatory events and osteoclastogenesis in vitro and reduced periodontal bone loss in vivo. Our study reveals succinate’s effect on periodontitis pathogenesis and provides a topical treatment for this disease.

Periodontitis is the most prevalent adult oral disease. Guo et al. show elevation of succinate in periodontitis, which aggravates the disease through the succinate receptor (SUCNR1). They developed a gel formulation of a small compound specifically blocking SUCNR1 to prevent and treat periodontitis by inhibiting dysbiosis, inflammation, and bone loss.

Proteolytic Activity-Independent Activation of the Immune Response by Gingipains from Porphyromonas gingivalis

Porphyromonas gingivalis, a keystone pathogen in periodontitis (PD), produces cysteine proteases named gingipains (RgpA, RgpB, and Kgp), which strongly affect the host immune system. The range of action of gingipains is extended by their release as components of outer membrane vesicles, which efficiently diffuse into surrounding gingival tissues. However, away from the anaerobic environment of periodontal pockets, increased oxygen levels lead to oxidation of the catalytic cysteine residues of gingipains, inactivating their proteolytic activity. In this context, the influence of catalytically inactive gingipains on periodontal tissues is of significant interest. Here, we show that proteolytically inactive RgpA induced a proinflammatory response in both gingival keratinocytes and dendritic cells. Inactive RgpA is bound to the cell surface of gingival keratinocytes in the region of lipid rafts, and using affinity chromatography, we identified RgpA-interacting proteins, including epidermal growth factor receptor (EGFR). Next, we showed that EGFR interaction with inactive RgpA stimulated the expression of inflammatory cytokines. The response was mediated via the EGFR–phosphatidylinositol 3-kinase (PI3K)-protein kinase B (AKT) signaling pathway, which when activated in the gingival tissue rich in dendritic cells in the proximity of the alveolar bone, may significantly contribute to bone resorption and the progress of PD. Taken together, these findings broaden our understanding of the biological role of gingipains, which in acting as proinflammatory factors in the gingival tissue, create a favorable milieu for the growth of inflammophilic pathobionts.

The Effects of Porphyromonas gingivalis on Atherosclerosis-Related Cells

Atherosclerosis (AS), one of the most common types of cardiovascular disease, has initially been attributed to the accumulation of fats and fibrous materials. However, more and more researchers regarded it as a chronic inflammatory disease nowadays. Infective disease, such as periodontitis, is related to the risk of atherosclerosis. Porphyromonas gingivalis (P. gingivalis), one of the most common bacteria in stomatology, is usually discovered in atherosclerotic plaque in patients. Furthermore, it was reported that P. gingivalis can promote the progression of atherosclerosis. Elucidating the underlying mechanisms of P. gingivalis in atherosclerosis attracted attention, which is thought to be crucial to the therapy of atherosclerosis. Nevertheless, the pathogenesis of atherosclerosis is much complicated, and many kinds of cells participate in it. By summarizing existing studies, we find that P. gingivalis can influence the function of many cells in atherosclerosis. It can induce the dysfunction of endothelium, promote the formation of foam cells as well as the proliferation and calcification of vascular smooth muscle cells, and lead to the imbalance of regulatory T cells (Tregs) and T helper (Th) cells, ultimately promoting the occurrence and development of atherosclerosis. This article summarizes the specific mechanism of atherosclerosis caused by P. gingivalis. It sorts out the interaction between P. gingivalis and AS-related cells, which provides a new perspective for us to prevent or slow down the occurrence and development of AS by inhibiting periodontal pathogens.

Macrophages in Microbial Pathogenesis: Commonalities of Defense Evasion Mechanisms

Macrophages are key arsenals of the immune system against invaders. After compartmental isolation of a pathogen in phagosomes, the host immune response attempts to neutralize the pathogen. However, pathogens possess the ability to subvert these assaults and can also convert macrophages into their replicative niche. The multiple host defense evasion mechanisms employed by these pathogens like phagosome maturation arrest, molecular mimicry through secretory antigens, interference with host signaling, active radical neutralization, inhibition of phagosome acidification, alteration of programmed cell death and many other mechanisms. Macrophage biology as a part of the host-pathogen interaction has expanded rapidly in the past decade. The present review aims to shed some light upon the macrophage defense evasion strategies employed by infecting pathogens. We have also incorporated recent knowledge in the field of macrophage dynamics during infection and evolutionary perspectives of macrophage dynamics.

Porphyromonas gingivalis survival skills: Immune evasion

Periodontitis is a chronic inflammatory condition that destroys the tooth-supporting tissues and eventually leads to tooth loss. As one of the most prevalent oral conditions, periodontitis endangers the oral health of 70% of people throughout the world. Periodontitis is also related to various systemic diseases, such as diabetes mellitus, atherosclerosis, and rheumatoid arthritis, which not only has a great impact on population health status and the quality of life but also increases the social burden. Porphyromonas gingivalis (P. gingivalis) is a gram-negative oral anaerobic bacterium that plays a key role in the pathogenesis of periodontitis. Porphyromonas gingivalis can express various of virulence factors to overturn innate and adaptive immunities, which makes P. gingivalis survive and propagate in the host, destroy periodontal tissues, and have connection to systemic diseases. Porphyromonas gingivalis can invade into and survive in host tissues by destructing the gingival epithelial barrier, internalizing into the epithelial cells, and enhancing autophagy in epithelial cells. Deregulation of complement system, degradation of antibacterial peptides, and destruction of phagocyte functions facilitate the evasion of P. gingivalis. Porphyromonas gingivalis can also suppress adaptive immunity, which allows P. gingivalis to exist in the host tissues and cause the inflammatory response persistently. Here, we review studies devoted to understanding the strategies utilized by P. gingivalis to escape host immunity. Methods for impairing P. gingivalis immune evasion are also mentioned.

Intersection between macrophages and periodontal pathogens in periodontitis

Periodontitis is a chronic infectious disease characterized by loss of periodontal attachment and resorption of alveolar bone. Dysregulated oral microbial community is the initial factor of periodontitis and causes excessive infiltration of immune cells in periodontal tissues. Macrophage, as an important part of the innate immune system, interacts continually with oral pathogens. Macrophages can recognize and phagocytize pathogens and apoptotic neutrophils and produce the specialized pro-resolving mediators (SPMs) playing an important role in maintaining the homeostasis of tissue microenvironment. However, macrophages may also induce abnormal immune responses with the overstimulation from pathogens, leading to the destruction of periodontal tissues and alveolar bone. Looking for targeted drugs that can regulate the activities of oral pathogens and the functions of macrophages provides a new idea for periodontitis treatment. This review summarizes the interaction between macrophages and periodontal pathogens in periodontitis, focusing on the pro-inflammation and anti-inflammation phenotypes of macrophages, and briefly concludes potential new methods of periodontitis therapy targeted at oral pathogens and macrophages.

Virulence mechanisms used in the pathogenesis of periodontal diseases caused by Porphyromonas gingivalis

Periodontal diseases are characterized by progressive inflammation that destroys the tooth-supporting tissues, leading to gum bleeding and tooth loss. Porphyromonas gingivalis is considered one of the main etiological agents responsible for the initiation and progression of chronic periodontitis. This gram-negative, anaerobic bacterium is a part of a multi-species oral biofilm. P. gingivalis does not have the full pathway of protoporphyrin IX synthesis, nor does it produce siderophores. Therefore, for survival and proliferation, it requires heme as a source of iron and protoporphyrin IX. In order to obtain heme, P. gingivalis uses a number of mechanisms that affect the ability of this bacterium to initiate a pathological condition. This review presents the current knowledge regarding the best-known and characterized systems involved in heme acquisition by P. gingivalis. We focused on processes occurring in the initial states of infection, where gingipain, hemagglutinins, and hemolysins play a crucial role. The mechanisms encoded by hmu, iht and hus operons, including proteins with hemophore-like properties, as well as TonB-dependent outer membrane receptors are described. We present their function and participation in the progression of the infection. In addition, we describe mechanisms produced by P. gingivalis and other periodontopathogens in synergistic processes promoting the growth and virulence of P. gingivalis. We also describe processes regulating iron and heme homeostasis, including the homolog of the Fur protein, the two-component system HaeSR, as well as the OxyR, SigH, and PgDps proteins.

Exercise Promotes the Osteoinduction of HA/β-TCP Biomaterials via the Wnt Signaling Pathway

To investigate the osteoinductive mechanism triggered by hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) biomaterials in mice which keep exercising. Methods: The HA/β-TCP biomaterials were implanted in the muscle of bilateral thighs (non-osseous sites) of eighty Balb/C mice. All animals were then randomly divided into 4 groups (n = 20). In group 1 (negative control group), the mice were fed routinely. In group 2 (running group), all mice were put on a treadmill which was set to a 60-degree incline. The mice ran 20 min thrice each day. A 5-minute break was included in the routine from day three onwards. In group 3 (weight-bearing group), all mice underwent weight-bearing running. The mice in this group performed the same routine as group 2 while carrying 5 g rubber weights. In group 4 (positive control group), dexamethasone was injected in the implanted sites of the biomaterials from the day of the operation. All mice were injected once per week and received a total of 8 injections. One and eight weeks after surgery, the blood serum was collected to detect inflammatory and immunological factors by ELISA. In addition to this, biomaterial specimens were obtained to observe inflammatory and osteogenic levels via histological staining and to facilitate analysis of the osteogenic mechanism by Western Blot. Results: The inflammation indexes caused by surgery were alleviated through running or weight-bearing running: The tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were significantly reduced in groups 2 and 3 at week 8. Exercise also enhanced the secretion of interferon-γ (IFN-γ) in mice; this can strengthen their immunity. The new bone tissues were observed in all groups; however, the area percentage of new bone tissues and the number of osteoblasts were highest in the weight-bearing group. Furthermore, the key proteins of wingless/integrated (Wnt) signaling pathway, Wnt1, Wnt3a, and β-catenin, were up-regulated during osteoinduction. This up-regulation activated runt-related transcription factor-2 (Runx2), increased the expression of osteopontin (OPN) and osteocalcin (OCN). Conclusion: Weight-bearing exercise can promote the bone and bone marrow formation through the Wnt signaling pathway: Observations documented here suggest that the proper exercise is beneficial to the recovery of bone damage.

Integrating complement into the molecular pathogenesis of Hidradenitis Suppurativa

Complement inhibition has been identified as a potential therapeutic target for multiple inflammatory disorders including Hidradenitis Suppurativa (HS). It is currently unclear how complement integrates into our current model of molecular pathogenesis in HS and whether it represents a central component of pathogenesis, or a neutrophil-associated bystander. Levels of C5a in serum and tissue correlate with disease activity and degree of neutrophilic infiltrates in HS. C5a has been associated with Th17 immune axis activation in psoriasis, rheumatoid arthritis and Crohn's disease with strong similarities to TH17 activation in HS. Porphyromonas species (which are identified in the HS microbiome) are able to cleave inactive C5 into C5a implicating the cutaneous microbiome as an activator of complement. C3a and C5a are associated with activation of the NLRP3 inflammasome, implicated in the inflammatory drive in HS. Complement receptors are present upon dendritic cells, monocytes, fibroblasts and adipocytes, which may broaden the potential contribution of complement to multiple aspects of HS pathogenesis. Dysregulation of complement receptor pathways has been documented in obesity, insulin resistance and polycystic ovarian syndrome leading to the possibility that complement may explain the epidemiological associations between these conditions and HS. The therapeutic potential of complement inhibitors in HS may be related to the therapeutic target (complement receptor or complement subunit) and the presence of alternate receptors (such as C5aR2) or ligands (including C3a, PAMPs and DAMPs). Integrating complement into the known pathogenesis of HS may aid in explaining the contradictory results between Phase 2 studies of C5a antagonists. It also allows for the identification of existing knowledge gaps to target further clinical investigation and research.

Activation of calcium signaling in human gingival fibroblasts by recombinant Porphyromonas gingivalis RgpB protein

Arginine-specific cysteine proteinases, such as Arg-gingipain B (RgpB), mediate inflammation by activating protease-activated receptors (PARs). Arg-gingipain B is produced by Porphyromonas gingivalis, and is implicated in the causation of periodontal disease. The purpose of the present study was to observe the influence of recombinant RgpB protein (rRgpB) on PAR activation by monitoring intracellular Ca2+ ion concentration ([Ca2+]i) and inositol-1,4,5-triphosphate (IP3) levels in human gingival fibroblasts (HGFs). Our findings showed that rRgpB could cause a transient increase in [Ca2+]i. This increase in [Ca2+]i was completely suppressed by vorapaxar, a PAR-1 antagonist. Recombinant Arg-gingipain B increased the concentration of IP3, reaching a maximum at 60 s after treatment; this was completely inhibited by vorapaxar. We therefore conclude that rRgpB-induced calcium signaling in HGFs is mainly caused by PAR-1 activation. This suggests that PAR-1 activation plays a significant role in chronic inflammatory periodontal disease induced by P. gingivalis RgpB.

Expression of human and Porphyromonas gingivalis glutaminyl cyclases in periodontitis and rheumatoid arthritis-A pilot study

OBJECTIVES

Human glutaminyl cyclases (QC and isoQC) play an important role in maintaining inflammatory conditions. Meanwhile a glutaminyl cyclase synthesized by Porphyromonas gingivalis (PgQC), a key pathogen in developing periodontitis and a potential link of periodontitis with rheumatoid arthritis (RA), was discovered. This study was aimed to determine the expression of QC, isoQC and PgQC in patients with chronic periodontitis (CP) and RA.

DESIGN

Thirty volunteers were enrolled in a pilot study and divided into 3 groups (healthy, CP and RA individuals). Blood samples, biofilm and gingival crevicular fluid (GCF) were analysed for mRNA expression of QC, isoQC and P. gingivalis QC. Major bacteria being associated with periodontal disease were quantified in subgingival biofilm and protein levels for monocyte chemoattractant protein (MCP)-1, MCP-3 and interleukin (IL)-1β) were determined in the GCF. Expression of PgQC on the mRNA and protein levels was assessed in two P. gingivalis strains.

RESULTS

PgQC is expressed in P. gingivalis strains and the protein seems to be located mainly in peri-plasmatic space. mRNA expression of QC was significantly increased in the peripheral blood from RA patients vs. healthy subjects and CP patients (p = 0.013 and p = 0.003, respectively). In GCF of RA patients, QC mRNA was detected more frequently than in healthy controls (p = 0.043). In these samples IL-1β levels were also elevated compared to GCF from periodontally healthy individuals (p = 0.003). PgQC was detected in eight out of the 13 P. gingivalis positive biofilm samples.

CONCLUSION

Activity of QC may play a supportive role in maintaining chronic periodontal inflammation and destruction in RA. PgQC is expressed in vivo but further research is needed to evaluate biological importance of this enzyme and if it constitutes a potential target in periodontal antimicrobial therapy.

Fetal Membrane Inflammation Induces Preterm Birth Via Toll-Like Receptor 2 in Mice With Chronic Gingivitis

Inflammation is associated with preterm birth. We previously described a mouse model of chronic inflammation-induced preterm birth after dental Porphyromonas gingivalis infection. The aim of this study was to employ this model system to investigate the mechanisms through which enhanced uterine contractility induces preterm birth. Messenger RNA (mRNA) encoding contraction-associated proteins, such as oxytocin receptors, was measured at various gestational time points by real-time polymerase chain reaction (PCR). Spontaneous and oxytocin-induced uterine contractile activity at gestational day 18 was assessed using a tissue organ bath. The expression levels of Toll-like receptor 2 (TLR2), TLR4, cyclooxygenase (COX)-2, nuclear factor-kappa B (NF-κB) p65, and p38 mitogen-activated protein kinase (MAPK) on gestational day 18 were also determined by real-time PCR or Western blotting. Messenger RNA encoding contraction-associated proteins was increased at gestational day 18, and the spontaneous contractile activity (1.6-fold greater area under the contraction curve) and sensitivity to oxytocin (EC₅₀: 8.8 nM vs 2.2 nM) were enhanced in the P gingivalis group compared to those in the control group. In the P gingivalis group, COX-2 mRNA expression was not elevated in the placenta or myometrium but was upregulated 2.3-fold in the fetal membrane. The TLR2 mRNA levels in the fetal membrane were 2.7-fold higher in the P gingivalis group, whereas TLR4 levels were not elevated. Activation of the NF-κB p65 and p38 MAPK pathways was enhanced in the fetal membrane of the P gingivalis group. Thus, in mice with chronic dental P gingivalis infection, TLR2-induced inflammation in the fetal membrane leads to upregulation of uterine contractility, leading to preterm birth.

Hesperetin and it nanocrystals ameliorate social behavior deficits and oxido-inflammatory stress in rat model of autism

Prenatal exposure to valproic acid (VPA) induces behavioral disorders and enhancement of oxido-inflammatory stress in Autism Spectrum Disorders (ASDs). The aim of this study was to investigate the comparative effects of hesperetin (Hst) and nano-hesperetin on social behavior deficits and oxido-inflammatory indexes in prenatally valproic acid-exposed rat offspring. Pregnant Wistar rats on embryonic day 0 (E0) were segregated into six groups; Group-1 served as vehicle, received distillated water orally (PO) from E1 until the end of lactation and saline intraperitoneally (i.p) on E12.5. Group-2 received sodium valproate (500 mg/kg in 0.9% saline, i.p) on E12.5 was considered as VPA-exposed group, Group-3 to 6 were VPA-exposed which received hesperetin and nano-hesperetin (10 and 20 mg/kg/day, PO) from E0 until the end of lactation respectively. Social interaction and open field tests were conducted on postnatal day 28 (PND 28) and PND 30, cerebral antioxidant enzymes activity and biochemical indexes, the level of inflammatory factors in plasma and histopathology of cerebellum were estimated on PND 28 and PND 30. Prenatal valproic acid-exposed rat exhibited poor sociability and high level of anxiety-like behaviors (P <  0.05). In addition, increased level of oxidative stress and inflammation were found by determining different oxido-inflammatory markers. Hesperetin and nano-hesperetin treatment improved the behavioral disorder and reduced the oxidative stress in brain and significantly (p <  0.05) plasma's inflammation indexes. In conclusion, it can be state that nano-hesperetin exerts neuroprotective action in comparison with hesperetin and could be efficacious for treatment of VPA animal model of autism during pregnancy and lactation.

Cytosolic DNA Sensing Promotes Macrophage Transformation and Governs Myocardial Ischemic Injury

BACKGROUND

Myocardium irreversibly injured by ischemic stress must be efficiently repaired to maintain tissue integrity and contractile performance. Macrophages play critical roles in this process. These cells transform across a spectrum of phenotypes to accomplish diverse functions ranging from mediating the initial inflammatory responses that clear damaged tissue to subsequent reparative functions that help rebuild replacement tissue. Although macrophage transformation is crucial to myocardial repair, events governing this transformation are poorly understood.

METHODS

Here, we set out to determine whether innate immune responses triggered by cytoplasmic DNA play a role.

RESULTS

We report that ischemic myocardial injury, along with the resulting release of nucleic acids, activates the recently described cyclic GMP-AMP synthase-stimulator of interferon genes pathway. Animals lacking cyclic GMP-AMP synthase display significantly improved early survival after myocardial infarction and diminished pathological remodeling, including ventricular rupture, enhanced angiogenesis, and preserved ventricular contractile function. Furthermore, cyclic GMP-AMP synthase loss of function abolishes the induction of key inflammatory programs such as inducible nitric oxide synthase and promotes the transformation of macrophages to a reparative phenotype, which results in enhanced repair and improved hemodynamic performance.

CONCLUSIONS

These results reveal, for the first time, that the cytosolic DNA receptor cyclic GMP-AMP synthase functions during cardiac ischemia as a pattern recognition receptor in the sterile immune response. Furthermore, we report that this pathway governs macrophage transformation, thereby regulating postinjury cardiac repair. Because modulators of this pathway are currently in clinical use, our findings raise the prospect of new treatment options to combat ischemic heart disease and its progression to heart failure.

Oral Biofilms from Symbiotic to Pathogenic Interactions and Associated Disease -Connection of Periodontitis and Rheumatic Arthritis by Peptidylarginine Deiminase

A wide range of bacterial species are harbored in the oral cavity, with the resulting complex network of interactions between the microbiome and host contributing to physiological as well as pathological conditions at both local and systemic levels. Bacterial communities inhabit the oral cavity as primary niches in a symbiotic manner and form dental biofilm in a stepwise process. However, excessive formation of biofilm in combination with a corresponding deregulated immune response leads to intra-oral diseases, such as dental caries, gingivitis, and periodontitis. Moreover, oral commensal bacteria, which are classified as so-called “pathobionts” according to a now widely accepted terminology, were recently shown to be present in extra-oral lesions with distinct bacterial species found to be involved in the onset of various pathophysiological conditions, including cancer, atherosclerosis, chronic infective endocarditis, and rheumatoid arthritis. The present review focuses on oral pathobionts as commensal and healthy members of oral biofilms that can turn into initiators of disease. We will shed light on the processes involved in dental biofilm formation and also provide an overview of the interactions of P. gingivalis, as one of the most prominent oral pathobionts, with host cells, including epithelial cells, phagocytes, and dental stem cells present in dental tissues. Notably, a previously unknown interaction of P. gingivalis bacteria with human stem cells that has impact on human immune response is discussed. In addition to this very specific interaction, the present review summarizes current knowledge regarding the immunomodulatory effect of P. gingivalis and other oral pathobionts, members of the oral microbiome, that pave the way for systemic and chronic diseases, thereby showing a link between periodontitis and rheumatoid arthritis.

Missing pieces of the puzzle to effectively control digital dermatitis

Since the first report of bovine digital dermatitis (DD) in 1974, there is a large body of the literature published; however, effective prevention and control of the disease remain elusive. Although many aspects of the pathogenesis of DD have been investigated, even some of the most basic questions such as the aetiology of this disease remain under debate. Treponema spp. have been strongly associated with DD lesions and occur in abundance in advanced lesions; however, efforts to induce disease with pure cultures of these organisms have been largely underwhelming and inconsistent. Furthermore, although the disease has been presented for several decades, there is limited scientific evidence regarding effective treatment of DD. Apparent discrepancies between effectiveness in vitro and in vivo have challenged the scientific community to identify new potential treatment options. With no treatment resulting in a 100% cure rate, the current expectation is manageable control, but prospects for the eradication of the disease are unlikely using current approaches. In order to develop more effective approaches to control DD on-farm, there is a critical need for a deeper understanding regarding the causation, ecology, transmission and treatment of this disease. In this article, we attempt to provide insights into specific research needs related to DD in order to assist the industry, researchers, pharmaceutical companies and research sponsors with decision-making and identified research gaps.

Immunomodulatory effect of photodynamic therapy in Galleria mellonella infected with Porphyromonas gingivalis

Porphyromonas gingivalis is an important pathogen in the development of periodontal disease. Our study investigated if the treatment with antimicrobial photodynamic therapy (aPDT) that employs a nontoxic dye, followed by irradiation with harmless visible light can attenuate the experimental infection of P. gingivalis in Galleria mellonella. Firstly, different concentrations of P. gingivalis ranging from 10² to 10⁶ cells/larva were injected into the animal to obtain a lethal concentration. Next, the following groups of G. mellonella infected with P. gingivalis were evaluated: inoculation of the photosensitizer and application of laser (P + L+), inoculation of physiologic solution and application of laser (P-L+), inoculation the photosensitizer without laser (P + L-) and inoculation of physiologic solution without Laser (P-L-). The effects of aPDT on infection by P. gingivalis were evaluated by survival curve analysis and hemocytes count. A lethal concentration of 10⁶ cells/larva was adopted for evaluating the effects of aPDT on experimental infection with P. gingivalis. We found that after 120 s of PDT application, the death of G. mellonella was significantly lower compared to the control groups (p = 0.0010). Moreover, the hemocyte density in the P+L+ group was increased by 9.6 × 10⁶ cells/mL (2.62-fold increase) compared to the infected larvae with no treatment (L-P- group) (p = 0.0175). Finally, we verified that the aPDT led to a significant reduction of the number of P. gingivalis cells in G. mellonella hemolymph. In conclusion, PDT application was effective against P. gingivalis infection by increasing the survival of G. mellonella and was able to increase the circulating hemocytes indicating that PDT activates the G. mellonella immune system.