Identification of signaling pathways mediating cell cycle arrest and apoptosis induced by Porphyromonas gingivalis in human trophoblasts

Intratumoral microbiota: a new force in the development and treatment of esophageal cancer

Esophageal cancer (EC) ranks among the most prevalent cancers worldwide, with a particularly high incidence in the Asian population. Due to the inconspicuous nature of early symptoms, patients with esophageal cancer are typically diagnosed in the middle to late stages, resulting in suboptimal overall treatment outcomes. Consequently, there is an urgent need to explore and refine therapeutic strategies. Microorganisms have been identified in numerous tumor tissues, including EC, and these microorganisms are referred to as the intratumoral microbiome. Intratumoral microbiota and their metabolic byproducts can influence the progression and treatment of esophageal cancer through various mechanisms, such as modulating tumor cell metabolism and local immune responses. Therefore, the intratumoral microbiota may potentially serve as a target for the treatment of esophageal cancer. This review delineates the composition, origin, and diagnostic significance of intratumoral microbiota in esophageal cancer tissue, and discusses the mechanisms by which intratumoral microbiota contribute to the onset of esophageal cancer. In addition, the impact of intratumoral microbiota on the treatment of esophageal cancer and its intervention measures are also addressed.

Group B streptococcus induces cellular senescence in human amnion epithelial cells through a partial interleukin-1-mediated mechanism

Group B streptococcus (GBS) infection is a significant public health concern associated with adverse pregnancy complications and increased neonatal mortality and morbidity. However, the mechanisms underlying the impact of GBS on the fetal membrane, the first line of defense against pathogens, are not fully understood. Here, we propose that GBS induces senescence and inflammatory factors (IL-6 and IL-8) in the fetal membrane through interleukin-1 (IL-1). Utilizing the existing transcriptomic data on GBS-exposed human fetal membrane, we showed that GBS affects senescence-related pathways and genes. Next, we treated primary amnion epithelial cells with conditioned medium from the choriodecidual layer of human fetal membrane exposed to GBS (GBS collected choriodecidual [CD] conditioned medium) in the absence or presence of an IL-1 receptor antagonist (IL-1Ra). GBS CD conditioned medium significantly increased β-galactosidase activity, IL-6 and IL-8 release from the amnion epithelial cells. Cotreatment with IL1Ra reduced GBS-induced β-galactosidase activity and IL-6 and IL-8 secretion. Direct treatment with IL-1α or IL-1β confirmed the role of IL-1 signaling in the regulation of senescence in the fetal membrane. We further showed that GBS CD conditioned medium and IL-1 decreased cell proliferation in amnion epithelial cells. In summary, for the first time, we demonstrate GBS-induced senescence in the fetal membrane and present evidence of IL-1 pathway signaling between the choriodecidua and amnion layer of fetal membrane in a paracrine manner. Further studies will be warranted to understand the pathogenesis of adverse pregnancy outcomes associated with GBS infection and develop therapeutic interventions to mitigate these complications.

Porphyromonas gingivalis outer membrane vesicles shape trophoblast cell metabolism impairing functions associated to adverse pregnancy outcome

Periodontitis is proposed as a risk factor for preterm delivery, fetal growth restriction, and preeclampsia with severe consequences for maternal and neonatal health, but the biological mechanisms involved are elusive. Porphyromonas gingivalis gain access to the placental bed and impair trophoblast cell function, as assessed in murine and human pregnancy, suggesting a pathogenic role in adverse pregnancy and neonatal outcomes. P. gingivalis releases outer membrane vesicles (P. gingivalis OMV) during growth that spread to distant tissues and are internalized in host cells as described in metabolic, neurological, and vascular systemic diseases. Here we tested the hypothesis that P. gingivalis OMV internalized in trophoblast cells disrupt their metabolism leading to trophoblast and placenta dysfunction and adverse pregnancy outcomes. An in vitro design with human trophoblast cells incubated with P. gingivalis OMV was used together with ex vivo and in vivo approaches in pregnant mice treated with P. gingivalis OMV. P. gingivalis OMV modulated human trophoblast cell metabolism by reducing glycolytic pathways and decreasing total reactive oxygen species with sustained mitochondrial activity. Metabolic changes induced by P. gingivalis OMV did not compromise cell viability; instead, it turned trophoblast cells into a metabolic resting state where central functions such as migration and invasion were reduced. The effects of P. gingivalis OMV on human trophoblast cells were corroborated ex vivo in mouse whole placenta and in vivo in pregnant mice: P. gingivalis OMV reduced glycolytic pathways in the placenta and led to lower placental and fetal weight gain in vivo with reduced placental expression of the glucose transporter GLUT1. The present results point to OMV as a key component of P. gingivalis involved in adverse pregnancy outcomes, and even more, unveil a metabolic cue in the deleterious effect of P. gingivalis OMV on trophoblast cells and mouse pregnancy, providing new clues to understand pathogenic mechanisms in pregnancy complications and other systemic diseases.

The effect of oral bacterial infection on DNA damage response in host cells

Maintaining and transferring intact genomes from one generation to another plays a pivotal role in all living organisms. DNA damage caused by numerous endogenous and exogenous factors must be adequately repaired, as unrepaired and accumulated DNA mutations can cause severe deleterious effects, such as cell death and cancer. To prevent adverse consequences, cells have established DNA damage response mechanisms that address different forms of DNA damage, including DNA double-strand breaks, mismatches, nucleotide excision, and base excision. Among several sources of exogenous DNA damage, bacterial infections cause inflammation in the host, generating reactive oxygen species (ROS) and causing oxidative DNA damage. Recent studies have revealed the importance of the oral microbiome in inflammation and several systemic host diseases. Dysbiosis of oral bacteria can induce chronic inflammation, which enhances ROS-induced DNA damage, and improperly repaired damage can lead to carcinogenesis. This review describes the various DNA repair pathways that are affected by chronic inflammation and the discovery of the DNA damage response induced by oral bacteria such as Porphyromonas gingivalis and Fusobacterium nucleatum.

Identification of key transcription factors and their functional role involved in Salmonella typhimurium infection in chicken using integrated transcriptome analysis and bioinformatics approach

Salmonella enterica serovar typhimurium is the cause of significant morbidity and mortality worldwide that causes economic losses to poultry and is able to cause infection in humans. Indigenous chicken breeds are a potential source of animal protein and have the added advantage of being disease resistant. An indigenous chicken, Kashmir favorella and commercial broiler were selected for understanding the mechanism of disease resistance. Following infection in Kashmir favorella, three differentially expressed genes Nuclear Factor Kappa B (NF-κB1), Forkhead Box Protein O3 (FOXO3) and Paired box 5 (Pax5) were identified. FOXO3, a transcriptional activator, is the potential marker of host resistance in Salmonella infection. NF-κB1 is an inducible transcription factor which lays the foundation for studying gene network of the innate immune response of Salmonella infection in chicken. Pax5 is essential for differentiation of pre-B cells into mature B cell. The real time PCR analysis showed that in response to Salmonella Typhimurium infection a remarkable increase of NF-κB1 (P˂0.01)_, FOXO3 (P˂0.01) gene expression in liver and Pax5 (P˂0.01) gene expression in spleen of Kashmir favorella was observed. The protein-protein interaction (PPI) and protein-TF interaction network by STRINGDB analysis suggests that FOXO3 is a hub gene in the network and is closely related to Salmonella infection along with NF-κB1. All the three differentially expressed genes (NF-κB1, FOXO3 and PaX5) showed their influence on 12 interacting proteins and 16 TFs, where cyclic adenosine monophosphate Response Element Binding protein (CREBBP), erythroblast transformation-specific (ETSI), Tumour-protein 53(TP53I), IKKBK, lymphoid enhancer-binding factor-1 (LEF1), and interferon regulatory factor-4 (IRF4) play role in immune responses. This study shall pave the way for newer strategies for treatment and prevention of Salmonella infection and may help in increasing the innate disease resistance.

Chinese medicine formula 'Baipuhuang Keli' inhibits triple-negative breast cancer by hindering DNA damage repair via MAPK/ERK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Baipuhuang Keli (BPH, constituted by Bai Tou Weng (Pulsatilla chinensis (Bunge) Regel), Pu Gong Ying (Taraxacum mongolicum Hand.-Mazz.), Huang Qin (Scutellaria baicalensis Georgi), Huang Bo (Phellodendron amurense Rupr.)) is a Chinese herbal formula with clearing heat and cooling blood, and removing toxin effects, which is suit for the case of breast cancer.

AIM OF THE STUDY

Here, we aim to explore the effects of BPH on triple-negative breast cancer (TNBC) and its potential mechanisms.

MATERIALS AND METHODS

In this study, cell viability assay, colony formation assay, soft agar assay, cell proliferation curve assay, and EdU assay were employed to determine the anti-proliferation effect induced by BPH. Cell cycle distribution was detected by flow cytometry. DNA damage in cells treated with BPH was indicated by comet assay, immunofluorescence, and Western Blot. Both the 4T1 orthotopic tumor model and the MDA-MB-231 subcutaneous tumor model were used to assess in vivo effect of BPH (312.5, and 625 mg/kg). The protein expression levels of the DNA damage response (DDR) pathway and the MAPK/ERK pathway were detected by Western Blot.

RESULTS

Our results indicated that TNBC cells were more sensitive to BPH than mammary epithelial cells. Cell proliferation of TNBC cells was significantly inhibited by BPH in a dose-dependent manner. Moreover, BPH induced DNA damage in TNBC cells in a concentration and time-dependent manner. DDR of TNBC cells was inhibited by BPH. MAPK/ERK pathway was inhibited in cells treated with BPH, and DNA damage can be reversed while EGF was added to activate MAPK/ERK pathway. The 4T1 orthotopic tumor model and the MDA-MB-231 subcutaneous tumor model further confirmed that BPH inhibited TNBC proliferation via inhibition of DDR and MAPK/ERK pathway in vivo.

CONCLUSIONS

Collectively, we proved that BPH is a potential anticancer Chinese herbal formula for TNBC in the manner of in vitro and in vivo experiments.

Periodontal Pathogens Promote Oral Squamous Cell Carcinoma by Regulating ATR and NLRP3 Inflammasome

Periodontitis is closely related to oral cancer, but the molecular mechanism of periodontal pathogens involved in the occurrence and development of oral cancer is still inconclusive. Here, we demonstrate that, in vitro, the cell proliferation ability and S phase cells of the periodontitis group (colonized by Porphyromonas gingivalis and Fusobacterium nucleatum, P+) significantly increased, but the G1 cells were obviously reduced. The animal models with an in situ oral squamous cell carcinoma (OSCC) and periodontitis-associated bacteria treatment were constructed, and micro-CT showed that the alveolar bone resorption of mice in the P+ group (75.3 ± 4.0 μm) increased by about 53% compared with that in the control group (48.8 ± 1.3 μm). The tumor mass and tumor growth rate in the P+ group were all higher than those in the blank control group. Hematoxylin-eosin (H&E) staining of isolated tumor tissues showed that large-scale flaky necrosis was found in the tumor tissue of the P+ group, with lots of damaged vascular profile and cell debris. Immunohistochemistry (IHC) of isolated tumor tissues showed that the expression of Ki67 and the positive rate of cyclin D1 were significantly higher in tumor tissues of the P+ group. The qRT-PCR results of the expression of inflammatory cytokines in oral cancer showed that periodontitis-associated bacteria significantly upregulated interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-18, apoptosis-associated speck-like protein containing a CARD (ASC) (up to six times), and caspase-1 (up to four times), but it downregulated nuclear factor (NF)-κB, NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3), and IL-1β (less than 0.5 times). In addition, the volume of spleen tissue and the number of CD4+ T cells, CD8+ T cells, and CD206+ macrophages in the P+ group increased significantly. IHC and Western blotting in tumor tissues showed that expression levels of γ-H2AX, p-ATR, RPA32, CHK1, and RAD51 were upregulated, and the phosphorylation level of CHK1 (p-chk1) was downregulated. Together, we identify that the periodontitis-related bacteria could promote tumor growth and proliferation, initiate the overexpressed NLRP3, and activate upstream signal molecules of ATR-CHK1. It is expected to develop a new molecular mechanism between periodontitis-related bacteria and OSCC.

Association between metabolic syndrome and periodontitis: The role of lipids, inflammatory cytokines, altered host response, and the microbiome

Periodontitis has been associated with many systemic diseases and conditions, including metabolic syndrome. Metabolic syndrome is a cluster of conditions that occur concomitantly and together they increase the risk of cardiovascular disease and double the risk of type 2 diabetes. In this review, we focus on the association between metabolic syndrome and periodontitis; however, we also include information on diabetes mellitus and cardiovascular disease, since these two conditions are significantly intertwined with metabolic syndrome. With regard to periodontitis and metabolic syndrome, to date, the vast majority of studies point to an association between these two conditions and also demonstrate that periodontitis can contribute to the development of, or can worsen, metabolic syndrome. Evaluating the effect of metabolic syndrome on the salivary microbiome, data presented herein support the hypothesis that the salivary bacterial profile is altered in metabolic syndrome patients compared with healthy patients. Considering periodontitis and these three conditions, the vast majority of human and animal studies point to an association between periodontitis and metabolic syndrome, diabetes, and cardiovascular disease. Moreover, there is evidence to suggest that metabolic syndrome and diabetes can alter the oral microbiome. However, more studies are needed to fully understand the influence these conditions have on each other.

Metabolic plasticity enables lifestyle transitions of Porphyromonas gingivalis

Our understanding of how the oral anaerobe Porphyromonas gingivalis can persist below the gum line, induce ecological changes, and promote polymicrobial infections remains limited. P. gingivalis has long been described as a highly proteolytic and asaccharolytic pathogen that utilizes protein substrates as the main source for energy production and proliferation. Here, we report that P. gingivalis displays a metabolic plasticity that enables the exploitation of non-proteinaceous substrates, specifically the monocarboxylates pyruvate and lactate, as well as human serum components, for colonization and biofilm formation. We show that anabolism of carbohydrates from pyruvate is powered by catabolism of amino acids. Concomitantly, the expression of fimbrial adhesion is upregulated, leading to the enhancement of biofilm formation, stimulation of multispecies biofilm development, and increase of colonization and invasion of the primary gingival epithelial cells by P. gingivalis. These studies provide the first glimpse into the metabolic plasticity of P. gingivalis and its adaptation to the nutritional condition of the host niche. Our findings support the model that in response to specific nutritional parameters, P. gingivalis has the potential to promote host colonization and development of a pathogenic community.

Roles of Porphyromonas gulae proteases in bacterial and host cell biology

Porphyromonas gulae, an animal-derived periodontal pathogen, expresses several virulence factors, including fimbria, lipopolysaccharide (LPS) and proteases. We previously reported that its invasive efficiency was dependent on fimbriae types. In addition, P. gulae LPS increased inflammatory responses via toll-like receptors. The present study was conducted to investigate the involvement of P. gulae proteases in bacterial and host cell biology. Porphyromonas gulae strains showed an ability to agglutinate mouse erythrocytes and also demonstrated co-aggregation with Actinomyces viscosus, while the protease inhibitors antipain, PMSF, TLCK and leupeptin diminished P. gulae proteolytic activity, resulting in inhibition of haemagglutination and co-aggregation with A. viscosus. In addition, specific proteinase inhibitors were found to reduce bacterial cell growth. Porphyromonas gulae inhibited Ca9-22 cell proliferation in a multiplicity of infection- and time-dependent manner. Additionally, P. gulae-induced decreases in cell contact and adhesion-related proteins were accompanied by a marked change in cell morphology from well spread to rounded. In contrast, inhibition of protease activity prevented degradation of proteins, such as E-cadherin, β-catenin and focal adhesion kinase, and also blocked inhibition of cell proliferation. Together, these results indicate suppression of the amount of human proteins, such as γ-globulin, fibrinogen and fibronectin, by P. gulae proteases, suggesting that a novel protease complex contributes to bacterial virulence.

MNSFβ Promotes the Proliferation and Migration of Human Extravillous Trophoblast Cells and the Villus Expression Level of MNSFβ Is Decreased in Recurrent Miscarriage Patients

AIMS

The invasion of extravillous trophoblast (EVT) cells into maternal decidua is essential for the establishment and maintenance of pregnancy. Derangement of EVT cell invasion might cause pregnancy complications including recurrent miscarriage (RM). We previously reported that deficiency of monoclonal nonspecific suppressor factor beta (MNSFβ) led to the early pregnancy failure in mice and the decidual MNSFβ expression level in RM patients was significantly decreased, but the underlying molecular mechanism of the role that MNSFβ played at the maternal-fetal interface remains unclear. Thus, in the present study, we determined effects of downregulated MNSFβ expression on human EVT cell activities.

METHODS

The MNSFβ expression in first-trimester human decidual and placental villus tissues was detected, respectively, by immunofluorescence or immunohistochemical analyses. The MNSFβ expression level in the immortalized first-trimester human EVT cell line HTR8/SVneo was downregulated by transfecting the small interfering RNA against MNSFβ and upregulated by transfecting the recombinant pDsRed-MNSFβ plasmids. The proliferation, migration, invasion, and apoptosis activities of HTR8/SVneo cells were, respectively, determined by cytometry assay, scratch test, transwell assay, and FITC/PI staining. The expression levels of P53, RhoA, Bcl-2, Bax, and MMP-9 in HTR8/SVneo cells, as well as the expression levels of MNSFβ and RhoA in placental villi of RM patients and physically normal pregnant women (NP), were examined by Western blot analysis.

RESULTS

MNSFβ protein signals were observed in first-trimester human villus and extravillous trophoblast cells. The downregulated MNSFβ expression significantly attenuated the proliferation, migration, and invasion abilities of HTR8/SVneo cells, accompanied with the obviously decreased expression levels of P53, RhoA, Bcl-2, Bax, and MMP-9, whereas the upregulated MNSFβ expression in HTR8/SVneo cells represented the inverse effects. Furthermore, expression levels of MNSFβ and RhoA in first-trimester human placental villus tissues of RM patients were significantly decreased compared to that of NP women.

CONCLUSION

These data suggested that MNSFβ promotes proliferation and migration of human EVT cells, probably via the P53 signaling pathway, and the deficiency of MNSFβ in placental villi might lead to early pregnancy loss by reducing proliferation and invasion activities of EVTs.

The mechanism of Mitogen-Activated Protein Kinases to mediate apoptosis and immunotoxicity induced by Benzo[a]pyrene on hemocytes of scallop Chlamys farreri in vitro

Benzo [a]pyrene (B [a]P) has received widespread attention for serious pollution in the sea, which may reduce immunity and lead to the outbreak of disease in bivalves. However, the mechanism of immunotoxicity induced by B [a]P in bivalves was still unclear. Previous studies have found that Mitogen-Activated Protein Kinases (MAPKs) including three classic pathways (ERK, p38 and JNK) play an important role in mediating this process. Thus, in order to explore the mechanism of immunotoxicity induced by B [a]P in scallop Chlamys farreri, hemocytes were treated with PD98059 (ERK inhibitor), SB203580 (p38 inhibitor) and SP600125 (JNK inhibitor) for 1 h and then incubation with B [a]P for 24 h at 1 μg/mL. Indexes including oxidative damage, apoptotic rate, and immune indicators were detected in the present study. The results showed that the increase of Reactive Oxygen Species (ROS) and DNA damage induced by B [a]P was inhibited with PD98059 and SB203580. Besides, lysosomal membrane stability (LMS) damage was promoted by PD98059, while it was opposite when treated with SB203580. Moreover, the ascended apoptosis rate induced by B [a]P was increased significantly after treatment with PD98059, but it was remarkably attenuated by SB203580 and SP600125. However, the opposite pattern was showed in phagocytosis compared with apoptosis rate in all of three inhibitors. In addition, antibacterial activity and bacteriolytic activity were enhanced by SB203580 while inhibited by PD98059. Therefore, these results showed that MAPKs directly or indirectly mediate the decrease of oxidative damage, apoptosis and immune defense ability of C. farreri hemocytes, which suggesting ERK/p38/JNK pathways have different functions in the apoptosis and immunity of C. farreri hemocytes after B [a]P exposure. In conclusion, this study intended to enrich the theoretical basis for immunotoxicology of bivalves exposed to pollutants.

BMAL1-Downregulation Aggravates Porphyromonas Gingivalis-Induced Atherosclerosis by Encouraging Oxidative Stress

RATIONALE

Atherosclerotic cardiovascular diseases are the leading cause of mortality worldwide. Atherosclerotic cardiovascular diseases are considered as chronic inflammation processes. In addition to risk factors associated with the cardiovascular system itself, pathogenic bacteria such as the periodontitis-associated Porphyromonas gingivalis (P gingivalis) are also closely correlated with the development of atherosclerosis, but the underlying mechanisms are still elusive.

OBJECTIVE

To elucidate the mechanisms of P gingivalis-accelerated atherosclerosis and explore novel therapeutic strategies of atherosclerotic cardiovascular diseases.

METHODS AND RESULTS

Bmal1-/- (brain and muscle Arnt-like protein 1) mice, ApoE-/- mice, Bmal1-/-ApoE-/- mice, conditional endothelial cell Bmal1 knockout mice (Bmal1fl/fl; Tek-Cre mice), and the corresponding jet-legged mouse model were used. Pgingivalis accelerates atherosclerosis progression by triggering arterial oxidative stress and inflammatory responses in ApoE-/- mice, accompanied by the perturbed circadian clock. Circadian clock disruption boosts P gingivalis-induced atherosclerosis progression. The mechanistic dissection shows that P gingivalis infection activates the TLRs-NF-κB signaling axis, which subsequently recruits DNMT-1 to methylate the BMAL1 promoter and thus suppresses BMAL1 transcription. The downregulation of BMAL1 releases CLOCK, which phosphorylates p65 and further enhances NF-κB signaling, elevating oxidative stress and inflammatory response in human aortic endothelial cells. Besides, the mouse model exhibits that joint administration of metronidazole and melatonin serves as an effective strategy for treating atherosclerotic cardiovascular diseases.

CONCLUSIONS

P gingivalis accelerates atherosclerosis via the NF-κB-BMAL1-NF-κB signaling loop. Melatonin and metronidazole are promising auxiliary medications toward atherosclerotic cardiovascular diseases.

RAS/MAPK signaling functions in oxidative stress, DNA damage response and cancer progression

Mitogen-activated protein kinase (MAPK) signaling pathways organize a great constitution network that regulates several physiological processes, like cell growth, differentiation, and apoptotic cell death. Due to the crucial importance of this signaling pathway, dysregulation of the MAPK signaling cascades is involved in the pathogenesis of various human cancer types. Oxidative stress and DNA damage are two important factors which in common lead to carcinogenesis through dysregulation of this signaling pathway. Reactive oxygen species (ROS) are a common subproduct of oxidative energy metabolism and are considered to be a significant physiological modulator of several intracellular signaling pathways including the MAPK pathway. Studies demonstrated that the MAP kinases extracellular signal-regulated kinase (ERK) 1/2 and p38 were activated in response to oxidative stress. In addition, DNA damage is a partly common circumstance in cell life and may result in mutation, cancer, and even cell death. Recently, accumulating evidence illustrated that the MEK/ERK pathway is associated with the suitable performance of cellular DNA damage response (DDR), the main pathway of tumor suppression. During DDR, the MEK/ERK pathway is regularly activated, which contributes to the appropriate activation of DDR checkpoints to inhibit cell division. Therefore, the aim of this review is to comprehensively discuss the critical function of MAPK signaling in oxidative stress, DNA damage, and cancer progression.

Porphyromonas gingivalis degrades integrin β1 and induces AIF-mediated apoptosis of epithelial cells

Background: Porphyromonas gingivalis, a major pathogen of chronic periodontitis, adheres to and invades epithelial cells via an interaction between fimbriae and integrin. P. gingivalis proliferation and infection may affect the survival of cells. In this study, we further examined alternative signaling pathways mediating epithelial-cell death induced by P. gingivalis and the role of the cell-adhesion molecule integrin. Methods: Human epithelial KB cells interacted with P. gingivalis to evaluate cell death by Annexin V-propidium iodide (PI) staining. JC-1 staining was used to measure mitochondrial membrane potential (MMP). The mRNA and protein of integrin β1, apoptosis-inducing factor (AIF) and caspase-3 were detected by real-time PCR and western blot. Caspase-3 activity was analyzed by spectrophotometry. Results: P. gingivalis infection downregulated integrin β1 and led to cell detachment in a dose and time-dependent manner. Large amount of P. gingivalis induced MMP depolarization and apoptosis in KB cells. Moreover, P. gingivalis up-regulated AIF, but not activate caspase-3 during apoptosis. In addition, AIF inhibitor N-Phenylmaleimide almost inhibited the P. gingivalis-induced apoptosis. Conclusions: P. gingivalis disrupts epithelial-cell adhesion by degrading integrin β1 and induces caspase-independent, AIF-mediated mitochondrial apoptosis, which may promote the damage of oral tissue.

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.

Adhesion and invasion of gingival epithelial cells by Porphyromonas gulae

Porphyromonas gulae, an animal periodontal pathogen, possess fimbriae classified into three genotypes (A-C) based on the diversity of fimA genes encoding FimA. Accumulating evidence suggests that P. gulae strains with type C fimbriae are more virulent as compared to those with other types. The ability of these organisms to adhere to and invade gingival epithelial cells has yet to be examined. P. gulae showed the greatest levels of adhesion and invasion at a multiplicity of infection of 100 for 90 min. P. gulae type C and some type B strains invaded gingival epithelial cells at significantly greater levels than the other strains, at the same level of efficiency as P. gingivalis with type II fimbriae. Adhesion and invasion of gingival epithelial cells by P. gulae were inhibited by cytochalasin D and sodium azide, indicating the requirements of actin polymerization and energy metabolism for those activities. Invasion within gingival epithelial cells was blocked by staurosporine, whereas those inhibitors showed little effects on adhesion, while nocodazole and cycloheximide had negligible effects on either adhesion or invasion. P. gulae proteases were found to be essential for adhesion and invasion of gingival epithelial cells, while its DNA and RNA, and protein synthesis were unnecessary for those activities. Additionally, α5β1 integrin antibodies significantly inhibited adhesion and invasion by P. gulae. This is the first report to characterize P. gulae adhesion and invasion of human gingival epithelial cells.

Down-regulation of DKK1 and Wnt1/β-catenin pathway by increased homeobox B7 resulted in cell differentiation suppression of intrauterine fetal growth retardation in human placenta

OBJECTIVE

This study aimed to test the influence of homeobox B7 (HoxB7) on the proliferation, invasion, and migration of human trophoblast cells and to reveal the down-regulation of HoxB7 on the transcriptional suppression of Dick Kopf-related protein1 (DKK1) and of Cysteine-rich glycosylated wingless protein 1 (Wnt1)/β-catenin in intrauterine fetal growth retardation (FGR).

METHODS

Quantitative measurement of HoxB7, DKK1, Wnt1, and β-catenin was performed in human placentas collected from normal pregnancies and from FGR with quantitative real time PCR (qRT-PCR). Cultured HTR-8/SVneo cells, transfected with a lentiviral plasmid that in-frame expresses human HoxB7 gene, were applied to functional assessment to study the biological impact of HoxB7 gene on DKK1, Wnt1, and β-catenin. Counting Kit-8, Transwell invasion assays, and flow cytometry were applied for the functional measurements.

RESULTS

The expression of HoxB7 was significantly increased, and of DKK1, Wnt1, and β-catenin was decreased, in FGR placenta tissues and in HTR-8/SVneo cells. Function studies revealed that overexpression of HoxB7 inhibited proliferation, migration, and invasion in HTR-8/SVneo cells. DKK1, Wnt1, and β-catenin were down-regulated in HTR-8/SVneo cells, inversely correlated with HoxB7 expression. Overexpression of HoxB7 showed a suppressive effect on proliferation, migration, and invasion in the HTR-8/SVneo cells.

CONCLUSIONS

Our results indicate that HoxB7 inhibited human trophoblast cell differentiation by down-regulating DKK1 expression and that it may affect transcription of Wnt1/β-catenin. The activation of HoxB7 might suppress the cell differentiation in HTR-8/SVneo cell cultures. The Wnt/β-catenin signaling pathway may play a significant role in the pathogenesis of FGR by regulating the invasion and proliferation of trophoblasts.

An insight into the role of the death receptor CD95 throughout pregnancy: Guardian, facilitator, or foe

The prototype death receptor CD95 (Fas) and its ligand, CD95L (FasL), have been thoroughly studied due to their role in immune homeostasis and elimination of infected and transformed cells. The fact that CD95 is present in female reproductive cells and modulated during embryogenesis and pregnancy has raised interest in its role in immune tolerance to the fetoplacental unit. CD95 has been shown to be critical for proper embryonic formation and survival. Moreover, altered expression of CD95 or its ligand causes autoimmunity and has also been directly involved in recurrent pregnancy losses and pregnancy disorders. The objective of this review is to summarize studies that evaluate the mechanisms involved in the activation of CD95 to provide an updated global view of its effect on the regulation of the maternal immune system. Modulation of the CD95 system components may be the immune basis of several common pregnancy disorders.

Periodontal infection with Porphyromonas gingivalis induces preterm birth and lower birth weight in rats

Preterm birth (PTB), accompanied by low birth weight (LBW) or not, is a syndrome with tremendous risk factors and long-term health consequences for children. In recent decades, overwhelming studies have shown that periodontitis contributes to prematurity and LBW. This study was conducted to determine the link between maternal periodontitis and the pathogenesis of PTB and/or LBW through a rat infection model induced by Porphyromonas gingivalis, an important periodontopathic bacterium. The murine model was established by surgically ligating the left mandibular first molars and inoculating with P. gingivalis, and then all female rats initiated mating 6 weeks post infection. The gestational day and birth weight were recorded, and blood, amniotic fluid, and placental specimens were collected. Rats with a PTB and LBW newborns were observed in the P. gingivalis-infected group. Additionally, P. gingivalis infection significantly increased the maternal serum levels of interferon-γ and interleukin-1β, whereas no significant difference in the cytokine response was observed in the amniotic fluid. Moreover, with the translocation of P. gingivalis to placentas, remarkable changes in gestational tissues were found, followed by significantly enhanced expression of Toll-like receptor 2 (TLR2) as well as Fas and Fas ligand (FasL). These results support the concept that severe cases of periodontitis caused by P. gingivalis infection may be indicative of rats being more susceptible to PTB/LBW, probably through the activation of the TLR2 and Fas/FasL pathways within the placental tissues. This study gave us new insight into how maternal periodontopathogens might be linked to placental damage and premature pathogenesis.

Cell Cycle Arrest and Apoptosis Induced by Porphyromonas gingivalis Require Jun N-Terminal Protein Kinase- and p53-Mediated p38 Activation in Human Trophoblasts

Porphyromonas gingivalis, a periodontal pathogen, has been implicated as a causative agent of preterm delivery of low-birth-weight infants. We previously reported that P. gingivalis activated cellular DNA damage signaling pathways and ERK1/2 that lead to G₁ arrest and apoptosis in extravillous trophoblast cells (HTR-8 cells) derived from the human placenta. In the present study, we further examined alternative signaling pathways mediating cellular damage caused by P. gingivalis. P. gingivalis infection of HTR-8 cells induced phosphorylation of p38 and Jun N-terminal protein kinase (JNK), while their inhibitors diminished both G₁ arrest and apoptosis. In addition, heat shock protein 27 (HSP27) was phosphorylated through both p38 and JNK, and knockdown of HSP27 with small interfering RNA (siRNA) prevented both G₁ arrest and apoptosis. Furthermore, regulation of G₁ arrest and apoptosis was associated with p21 expression. HTR-8 cells infected with P. gingivalis exhibited upregulation of p21, which was regulated by p53 and HSP27. These results suggest that P. gingivalis induces G₁ arrest and apoptosis via novel molecular pathways that involve p38 and JNK with its downstream effectors in human trophoblasts.

Galectin-3 Plays an Important Role in Preterm Birth Caused by Dental Infection of Porphyromonas gingivalis

Dental infection is risk for preterm birth (PTB) through unclear mechanisms. We established a dental infection-induced PTB mouse model, in which Porphyromonas gingivalis (P.g.) induced PTB by 2 days. We analysed pathogenic factors contributing to PTB and their effects on trophoblasts in vitro. TNF-α, IL-8, and COX-2 were upregulated in P.g.-infected placenta. Galectin-3 (Gal-3), an immune regulator, was significantly upregulated in placenta, amniotic fluid, and serum. In vitro, P.g.-lipopolysaccharide (P.g.-LPS) increased TNF-α and Gal-3 in trophoblasts via NF-κB/MAPK signalling. Gal-3 inhibition significantly downregulated P.g.-LPS-induced TNF-α production. TNF-α upregulated Gal-3. Gal-3 also increased cytokines and Gal-3 through NF-κB/MAPK signalling. Moreover, Gal-3 suppressed CD-66a expression at the maternal-foetal interface. Co-stimulation with Gal-3 and P.g.-LPS upregulated cytokine levels, while Gal-3 plus Aggregatibacter actinomycetemcomitans (A.a.)- or Escherichia coli (E. coli)-LPS treatment downregulated them, indicating the critical role of Gal-3 especially in P.g. dental infection-induced PTB. P.g.-dental infection induced PTB, which was associated with Gal-3-dependent cytokine production. New therapies and/or diagnostic systems targeting Gal-3 may reduce PTB.

Porphyromonas gingivalis and adverse pregnancy outcome

Porphyromonas gingivalis is a Gram-negative, anaerobic bacterium considered to be an important pathogen of periodontal disease that is also implicated in adverse pregnancy outcome (APO). Until recently, our understanding of the role of P. gingivalis in APO has been limited and sometimes contradictory. The purpose of this review is to provide an overview of past and current research on P. gingivalis that addresses some of the controversies concerning the role of this organism in the pathogenesis of APO.

Molecular mechanisms of Porphyromonas gingivalis-host cell interaction on periodontal diseases

Porphyromonas gingivalis (P. gingivalis) is a major oral pathogen and associated with periodontal diseases including periodontitis and alveolar bone loss. In this review, we indicate that two virulence factors, which are hemoglobin receptor protein (HbR) and cysteine proteases “gingipains”, expressed by P. gingivalis have novel functions on the pathogenicity of P. gingivalis. P. gingivalis produces three types of gingipains and concomitantly several adhesin domains. Among the adhesin domains, hemoglobin receptor protein (HbR), also called HGP15, has the function of induction of interleukin-8 (IL-8) expression in human gingival epithelial cells, indicating the possibility that HbR is associated with P. gingivalis-induced periodontal inflammation. On bacteria-host cells contact, P. gingivalis induces cellular signaling alteration in host cells. Phosphatidylinositol 3-kinase (PI3K) and Akt are well known to play a pivotal role in various cellular physiological functions including cell survival and glucose metabolism in mammalian cells. Recently, we demonstrated that gingipains attenuate the activity of PI3K and Akt, which might have a causal influence on periodontal diseases by chronic infection to the host cells from the speculation of molecular analysis. In this review, we discuss new molecular and biological characterization of the virulence factors from P. gingivalis.

Role of Maternal Periodontitis in Preterm Birth

In the last two decades, many studies have focused on whether periodontitis is a risk factor for preterm birth (PTB). However, both epidemiological investigation and intervention trials have reached contradictory results from different studies. What explains the different findings, and how should future studies be conducted to better assess this risk factor? This article reviews recent epidemiological, animal, and in vitro studies as well as intervention trials that evaluate the link between periodontitis and PTB. Periodontitis may act as a distant reservoir of microbes and inflammatory mediators and contribute to the induction of PTB. Animal studies revealed that maternal infections with periodontal pathogens increase levels of circulating IL-1β, IL-6, IL-8, IL-17, and TNF-α and induce PTB. In vitro models showed that periodontal pathogens/byproducts induce COX-2, IL-8, IFN-γ, and TNF-α secretion and/or apoptosis in placental tissues/cells. The effectiveness of periodontal treatment to prevent PTB is influenced by the diagnostic criteria of periodontitis, microbial community composition, severity of periodontitis, treatment strategy, treatment efficiency, and the period of treatment during pregnancy. Although intervention trials reported contradictory results, oral health maintenance is an important part of preventive care that is both effective and safe throughout pregnancy and should be supported before and during pregnancy. As contradictory epidemiological and intervention studies continue to be published, two new ideas are proposed here: (1) severe and/or generalized periodontitis promotes PTB and (2) periodontitis only promotes PTB for pregnant women who are young or HIV-infected or have preeclampsia, pre-pregnancy obesity, or susceptible genotypes.

Expression of long non-coding RNA-HOTAIR in oral squamous cell carcinoma Tca8113 cells and its associated biological behavior

As a long noncoding RNA, HOX transcript antisense intergenic RNA (HOTAIR) is highly expressed in many types of tumors. However, its expression and function in oral squamous cell carcinoma (OSCC) cells and tissues remains largely unknown. We herein studied the biological functions of HOTAIR in OSCC Tca8113 cells. Real-time quantitative PCR showed that HOTAIR, p21 and p53 mRNA expressions in doxorubicin (DOX)-treated or γ-ray-irradiated Tca8113 cells were up-regulated. Knockdown of p53 expression inhibited DOX-induced HOTAIR up-regulation, suggesting that DNA damage-induced HOTAIR expression may be associated with p53. Transfection and CCK-8 assays showed that compared with the control group, overexpression of HOTAIR promoted the proliferation of Tca8113 cells, while interfering with its expression played an opposite role. Flow cytometry exhibited that HOTAIR overexpression decreased the rate of DOX-induced apoptosis. When HOTAIR expression was inhibited by siRNA, the proportions of cells in G₂/M and S phases increased and decreased respectively. Meanwhile, the rate of DOX-induced apoptosis rose. DNA damage-induced HOTAIR expression facilitated the proliferation of Tca8113 cells and decreased their apoptosis. However, whether the up-regulation depends on p53 still needs in-depth studies.

Porphyromonas gingivalis induces IL-8 and IFN-gamma secretion and apoptosis in human extravillous trophoblast derived HTR8/SVneo cells via activation of ERK1/2 and p38 signaling pathways

INTRODUCTION

Preterm birth is a major cause for infant mortality and morbidity. A large number of studies have suggested a link between periodontal disease and preterm birth. The purpose of this study was to investigate the interaction between a periodontopathic bacterium Porphyromonas gingivalis and human extravillous trophoblast derived HTR8/SVneo cells.

METHODS

Production of cytokines in HTR8 cells was measured via ELISA. Annexin V/PI flow cytometry was performed to assess apoptosis. Protein expression was measured by western blot. Specific pharmacological inhibitors were used to inactivate relevant signaling pathways (p38 MAPK, SB203580; ERK1/2, U0126; JNK, SP600125; NF-κB, JSH-23) to determine their roles in inflammation and apoptosis.

RESULTS

HTR8 cells released significant amounts of IL-8 and IFN-γ during exposure to P. gingivalis. Meanwhile, the percentages of both early and late apoptotic cells increased significantly in response to P. gingivalis. The most significant effect on inflammation was found using SB203580 and U0126, followed by SP600125 and JSH-23. Moreover, U0126 and SB203580 both partially but significantly suppressed P. gingivalis-induced apoptosis, with a large effect by U0126. Additionally, both heat-killed P. gingivalis and P. gingivalis lipopolysaccharide significantly induced IL-8 production.

CONCLUSION

P. gingivalis induces inflammation and apoptosis in HTR8 cells, and we demonstrated for the first time that activation of ERK1/2 and p38 MAPK pathways participates in P. gingivalis-induced inflammation and apoptosis. The abnormal regulation of inflammation and apoptosis in human trophoblasts by P. gingivalis infection may give new insights into how maternal periodontal disease and periodontal pathogens might be linked to preterm birth.

Presence of Porphyromonas gingivalis in esophagus and its association with the clinicopathological characteristics and survival in patients with esophageal cancer

Background

Mounting evidence suggests a causal relationship between specific bacterial infections and the development of certain malignancies. However, the possible role of the keystone periodontal pathogen, Porphyromonas gingivalis, in esophageal squamous cell carcinoma (ESCC) remains unknown. Therefore, we examined the presence of P. gingivalis in esophageal mucosa, and the relationship between P. gingivalis infection and the diagnosis and prognosis of ESCC.

Methods

The presence of P. gingivalis in the esophageal tissues from ESCC patients and normal controls was examined by immunohistochemistry using antibodies targeting whole bacteria and its unique secreted protease, the gingipain Kgp. qRT-PCR was used as a confirmatory approach to detect P. gingivalis 16S rDNA. Clinicopathologic characteristics were collected to analyze the relationship between P. gingivalis infection and development of ESCC.

Results

P. gingivalis was detected immunohistochemically in 61 % of cancerous tissues, 12 % of adjacent tissues and was undetected in normal esophageal mucosa. A similar distribution of lysine-specific gingipain, a catalytic endoprotease uniquely secreted by P. gingivalis, and P. gingivalis 16S rDNA was also observed. Moreover, statistic correlations showed P. gingivalis infection was positively associated with multiple clinicopathologic characteristics, including differentiation status, metastasis, and overall survival rate.

Conclusion

These findings demonstrate for the first time that P. gingivalis infects the epithelium of the esophagus of ESCC patients, establish an association between infection with P. gingivalis and the progression of ESCC, and suggest P. gingivalis infection could be a biomarker for this disease. More importantly, these data, if confirmed, indicate that eradication of a common oral pathogen could potentially contribute to a reduction in the overall ESCC burden.

Electronic supplementary material

The online version of this article (doi:10.1186/s13027-016-0049-x) contains supplementary material, which is available to authorized users.

Noncanonical activation of β-catenin by Porphyromonas gingivalis

Porphyromonas gingivalis is an established pathogen in periodontal disease and an emerging pathogen in serious systemic conditions, including some forms of cancer. We investigated the effect of P. gingivalis on β-catenin signaling, a major pathway in the control of cell proliferation and tumorigenesis. Infection of gingival epithelial cells with P. gingivalis did not influence the phosphorylation status of β-catenin but resulted in proteolytic processing. The use of mutants deficient in gingipain production, along with gingipain-specific inhibitors, revealed that gingipain proteolytic activity was required for β-catenin processing. The β-catenin destruction complex components Axin1, adenomatous polyposis coli (APC), and GSK3β were also proteolytically processed by P. gingivalis gingipains. Cell fractionation and Western blotting demonstrated that β-catenin fragments were translocated to the nucleus. The accumulation of β-catenin in the nucleus following P. gingivalis infection was confirmed by immunofluorescence microscopy. A luciferase reporter assay showed that P. gingivalis increased the activity of the β-catenin-dependent TCF/LEF promoter. P. gingivalis did not increase Wnt3a mRNA levels, a finding consistent with P. gingivalis-induced proteolytic processing causing the increase in TCF/LEF promoter activity. Thus, our data indicate that P. gingivalis can induce the noncanonical activation of β-catenin and disassociation of the β-catenin destruction complex by gingipain-dependent proteolytic processing. β-Catenin activation in epithelial cells by P. gingivalis may contribute to a proliferative phenotype.

Attenuation of the phosphatidylinositol 3-kinase/Akt signaling pathway by Porphyromonas gingivalis gingipains RgpA, RgpB, and Kgp

Porphyromonas gingivalis is a major pathogen of periodontal diseases, including periodontitis. We have investigated the effect of P. gingivalis infection on the PI3K/Akt (protein kinase B) signaling pathway in gingival epithelial cells. Here, we found that live P. gingivalis, but not heat-killed P. gingivalis, reduced Akt phosphorylation at both Thr-308 and Ser-473, which implies a decrease in Akt activity. Actually, PI3K, which is upstream of Akt, was also inactivated by P. gingivalis. Furthermore, glycogen synthase kinase 3α/β, mammalian target of rapamycin, and Bad, which are downstream proteins in the PI3K/Akt cascade, were also dephosphorylated, a phenomenon consistent with Akt inactivation by P. gingivalis. However, these events did not require direct interaction between bacteria and host cells and were independent of P. gingivalis invasion into the cells. The use of gingipain-specific inhibitors and a gingipain-deficient P. gingivalis mutant KDP136 revealed that the gingipains and their protease activities were essential for the inactivation of PI3K and Akt. The associations between the PI3K regulatory subunit p85α and membrane proteins were disrupted by wild-type P. gingivalis. Moreover, PDK1 translocation to the plasma membrane was reduced by wild-type P. gingivalis, but not KDP136, indicating little production of phosphatidylinositol 3,4,5-triphosphate by PI3K. Therefore, it is likely that PI3K failed to transmit homeostatic extracellular stimuli to intracellular signaling pathways by gingipains. Taken together, our findings indicate that P. gingivalis attenuates the PI3K/Akt signaling pathway via the proteolytic effects of gingipains, resulting in the dysregulation of PI3K/Akt-dependent cellular functions and the destruction of epithelial barriers.

[Recent advances in the field of oral bacteriology]

The oral cavity is inhabited by more than 600 bacterial species; these species compete for nutrients or coexist in order to survive along with the indigenous population. Extreme conditions are prevalent in the oral cavity, and these conditions are influenced by our immunity and variations in nutrition, temperature, and pH. Pathogens that cause dental caries or periodontal disease can survive in these extreme environments; these pathogens are virulent and can cause several diseases. Therefore, research on oral bacteriology is warranted to analyze the virulence factors of these bacteria as well as to ascertain environmental stress responses, interactions between bacteria and human immunity, comparisons of bacterial genomes, and oral microflora. In this review, we provide new data in the fields of bacteriology, immunology, and genomics and describe recent advances in the field of oral bacteriology.

Future directions of clinical laboratory evaluation of pregnancy

In recent years, our understanding of how the immune system interacts with the developing fetus and placenta has greatly expanded. There are many laboratories that provide tests for diagnosis of pregnancy outcome in women who have recurrent pregnancy loss (RPL) or pre-eclampsia. These tests are based on the premise that immune response to the fetus is equivalent to the adaptive immune response to a transplant. New understanding leads to the concept that the activated innate response is vital for pregnancy and this can result in more effective testing and treatment to prevent an abnormal pregnancy in the future. We describe here only three such areas for future testing: one area involves sperm and semen and factors necessary for successful fertilization; another area would determine conditions for production of growth factors necessary for implantation in the uterus; finally, the last area would be to determine conditions necessary for the vascularization of the placenta and growing fetus by activated natural killer (NK) cells (combinations of killer cell immunoglobulin-like receptor (KIR) family genes with HLA-C haplotypes) that lead to capability of secreting angiogenic growth factors. These areas are novel but understanding their role in pregnancy can lead to insight into how to maintain and treat pregnancies with complicating factors.

Porphyromonas gingivalis-induced autophagy suppresses cell proliferation through G1 arrest in oral cancer cells

OBJECTIVES

We investigated the response of oral cancer cells to intracellular invasion of Porphyromonas gingivalis to define changes in the biological characteristics of oral cancer cells evoked by the presence of oral pathogenic bacteria within a tumour microenvironment.

DESIGNS

The proliferative activity, cell cycle, and autophagic response were evaluated in oral cancer cells infected with P. gingivalis 381. ROS generation was detected in these cells by DCFDA assay, and its role in the responses of oral cancer cells to P. gingivalis infection was further investigated.

RESUTLS

P. gingivalis inhibited proliferation of oral cancer cells by inducing G1 cell cycle arrest, but had no effect on apoptosis. Following infection with P. gingivalis, the expression of cyclin D1 and cdk4 was decreased in oral cancer cells, whereas p21, a Cdk inhibitor, was upregulated, in comparison with non-infected controls. Autophagy was prominently enhanced in these infected cells, presumably contributing to the suppressed proliferation. Further experiments revealed that such autophagic response was activated by the formation of reactive oxygen species, as evidenced by the lack of autophagic response and cell proliferation upon removal of reactive oxygen species.

CONCLUSIONS

These findings provide a novel insight into the mechanism by which cancer cells are influenced by tumour microenvironment including oral bacteria.

Review of Ets1 structure, function, and roles in immunity

The Ets1 transcription factor is a member of the Ets gene family and is highly conserved throughout evolution. Ets1 is known to regulate a number of important biological processes in normal cells and in tumors. In particular, Ets1 has been associated with regulation of immune cell function and with an aggressive behavior in tumors that express it at high levels. Here we review and summarize the general features of Ets1 and describe its roles in immunity and autoimmunity, with a focus on its roles in B lymphocytes. We also review evidence that suggests that Ets1 may play a role in malignant transformation of hematopoietic malignancies including B cell malignancies.