Loss of TDP-43 splicing repression occurs early in the aging population and is associated with Alzheimer's disease neuropathologic changes and cognitive decline.

LATE-NC, the neuropathologic changes of limbic-predominant age-related TAR DNA-binding protein 43 kDa (TDP-43) encephalopathy are frequently associated with Alzheimer's disease (AD) and cognitive impairment in older adults. The association of TDP-43 proteinopathy with AD neuropathologic changes (ADNC) and its impact on specific cognitive domains are not fully understood and whether loss of TDP-43 function occurs early in the aging brain remains unknown. Here, using a large set of autopsies from the Baltimore Longitudinal Study of Aging (BLSA) and another younger cohort, we were able to study brains from subjects 21-109 years of age. Examination of these brains show that loss of TDP-43 splicing repression, as judged by TDP-43 nuclear clearance and expression of a cryptic exon in HDGFL2, first occurs during the 6th decade, preceding by a decade the appearance of TDP-43+ neuronal cytoplasmic inclusions (NCIs). We corroborated this observation using a monoclonal antibody to demonstrate a cryptic exon-encoded neoepitope within HDGFL2 in neurons exhibiting nuclear clearance of TDP-43. TDP-43 nuclear clearance is associated with increased burden of tau pathology. Age at death, female sex, high CERAD neuritic plaque score, and high Braak neurofibrillary stage significantly increase the odds of LATE-NC. Faster rates of cognitive decline on verbal memory (California Verbal Learning Test immediate recall), visuospatial ability (Card Rotations Test), mental status (MMSE) and semantic fluency (Category Fluency Test) were associated with LATE-NC. Notably, the effects of LATE-NC on verbal memory and visuospatial ability are independent of ADNC. However, the effects of TDP-43 nuclear clearance in absence of NCI on the longitudinal trajectories and levels of cognitive measures are not significant. These results establish that loss of TDP-43 splicing repression is an early event occurring in the aging population during the development of TDP-43 proteinopathy and is associated with increased tau pathology. Furthermore, LATE-NC correlates with high levels of ADNC but also has an impact on specific memory and visuospatial functions in aging that is independent of AD.

The TNF-Alpha Inducing Protein is Associated With Gastric Inflammation and Hyperplasia in a Murine Model of Helicobacter pylori Infection.

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that colonizes the human stomach leading to the development of chronic gastritis, peptic ulcers and gastric adenocarcinoma. A combination of host, environment and bacterial virulence factors contribute to disease development. The H. pylori TNFα inducing protein (Tipɑ) is a virulence factor shown to induce multiple pro-inflammatory cytokines in addition to TNFα in vitro. The goal of the present study was to elucidate the role of Tipα in promoting inflammation in vivo and to identify the molecular pathways associated with Tipα associated virulence. Mice were infected with wild-type Sydney strain (SS1) or a tipα mutant (Δtipα) for 1 month and 4 months. We also completed a second 4 months infection including a 1:1 SS1 to Δtipα co-infected group in addition to SS1 and Δtipα infected groups. The expression of TNFα, and KC were significantly higher in the SS1 infected group compared to both uninfected control (naïve) and Δtipα groups. Mice infected with Tipα expressing SS1 induced more severe histological gastritis and developed hyperplasia compared to Δtipα infected mice. Microarray analysis of gastric epithelial cells co-cultured with recombinant Tipα (rTipα) demonstrates up-regulation of the NFκB pathway. This data suggest Tipα plays an important role in H. pylori induced inflammation.

SARS-CoV-2 invades cognitive centers of the brain and induces Alzheimer's-like neuropathology.

The neurotropism of SARS-CoV-2 and the phenotypes of infected neurons are still in debate. Long COVID manifests with "brain diseases" and the cause of these brain dysfunction is mysterious. Here, we analyze 34 age- and underlying disease-matched COVID-19 or non-COVID-19 human brains. SARS-CoV-2 RNA, nucleocapsid, and spike proteins are present in neurons of the cognitive centers of all COVID-19 patients, with its non-structural protein NSF2 detected in adult cases but not in the infant case, indicating viral replications in mature neurons. In adult COVID-19 patients without underlying neurodegeneration, SARS-CoV-2 infection triggers Aß and p-tau deposition, degenerating neurons, microglia activation, and increased cytokine, in some cases with Aß plaques and p-tau pretangles. The number of SARS-CoV-2 + cells is higher in patients with neurodegenerative diseases than in those without such conditions. SARS-CoV-2 further activates microglia and induces Aß and p-tau deposits in non-Alzheimer's neurodegenerative disease patients. SARS-CoV-2 infects mature neurons derived from inducible pluripotent stem cells from healthy and Alzheimer's disease (AD) individuals through its receptor ACE2 and facilitator neuropilin-1. SARS-CoV-2 triggers AD-like gene programs in healthy neurons and exacerbates AD neuropathology. An AD infectious etiology gene signature is identified through SARS-CoV-2 infection and silencing the top three downregulated genes in human primary neurons recapitulates the neurodegenerative phenotypes of SARS-CoV-2. Thus, our data suggest that SARS-CoV-2 invades the brain and activates an AD-like program.

Impact of Andrographolide and Melatonin Combinatorial Drug Therapy on Metastatic Colon Cancer Cells and Organoids.

BACKGROUND: The death rate (the number of deaths per 100 000 people per year) of colorectal cancer (CRC) has been dropping since 1980 due to increased screening, lifestyle-related risk factors, and improved treatment options; however, CRC is the third leading cause of cancer-related deaths in men and women in the United States. Therefore, successful therapy for CRC is an unmet clinical need. This study aimed to investigate the impacts of andrographolide (AGP) and melatonin (MLT) on CRC and the underlying mechanism. METHODS: To investigate AGP and MLT anticancer effects, a series of metastatic colon cancer cell lines (T84, Colo 205, HT-29, and DLD-1) were selected. In addition, a metastatic patient-derived organoid model (PDOD) was used to monitor the anticancer effects of AGP and MLT. A series of bioassays including 3D organoid cell culture, MTT, colony formation, western blotting, immunofluorescence, and quantitative polymerase chain reaction (qPCR) were performed. RESULTS: The dual therapy significantly promotes CRC cell death, as compared with the normal cells. It also limits CRC colony formation and disrupts the PDOD membrane integrity along with decreased Ki-67 expression. A significantly higher cleaved caspase-3 and the endoplasmic reticulum (ER) stress proteins, IRE-1 and ATF-6 expression, by 48 hours were found. This combinatorial treatment increased reactive oxygen species (ROS) levels. Apoptosis signaling molecules BAX, XBP-1, and CHOP were significantly increased as determined by qPCR. CONCLUSIONS: These findings indicated that AGP and MLT associated ER stress-mediated apoptotic metastatic colorectal cancer (mCRC) cell death through the IRE-1/XBP-1/CHOP signaling pathway. This novel combination could be a potential therapeutic strategy for mCRC cells.

Synergistic potential of dual andrographolide and melatonin targeting of metastatic colon cancer cells: Using the Chou-Talalay combination index method.

Colorectal cancer (CRC) mortality has diminished for decades due to new and improved treatment profiles. However, CRC still ranks as the third most diagnosed cancer in the US. Therefore, a new therapeutic approach is needed to overcome colospheroids inhibition and drug resistance. It is well documented that andrographolide (AGP) and melatonin (MLT) have anti-carcinogenic properties. Our goal was to evaluate their synergistic effects on metastatic colon cancer cells (mCRC) and colospheroids. HT-29 and HCT-15 mCRC cells were simultaneously treated with serial dilutions of AGP and MLT for 24, 48 and 72 h. Cell viability was monitored using the MTT assay. The Chou-Talalay method for drug combination is based on the median effect equation, providing a theoretical basis for the combination index and the isobologram equation. This allows quantitative determination of drug interactions using the CompuSyn software, where CI < 1, = 1, and >1 indicates synergistic, additive, and antagonistic effects respectively. Our results demonstrate that AGP and MLT in combination show synergism with CI values of 0.35293 and 0.34152 for HT-29 and HCT-15 respectively and a fractional inhibition of Fa = 0.50-0.90, as shown by the Fa-CI plot and isobologram. The synergism value was validated in colospheroids (HT-29-s and HCT-15-s) based on morphology, viability, and colony formation and in 5-FU drug resistant cell (HT-29R and HCT-116R) viability. The mechanism(s) of decreased cell viability are due to the induction of ER stress proteins and angiogenic inhibition. Our results provide rationale for using AGP in combination with MLT on mCRC.

Crosstalk between endoplasmic reticulum stress and anti-viral activities: A novel therapeutic target for COVID-19.

The outbreak of COVID-19 caused by 2019-nCov/SARS-CoV-2 has become a pandemic with an urgent need for understanding the mechanisms and identifying a treatment. Viral infections including SARS-CoV are associated with increased levels of reactive oxygen species, disturbances of Ca++ caused by unfolded protein response (UPR) mediated by endoplasmic reticulum (ER) stress and is due to the exploitation of virus's own protein i.e., viroporins into the host cells. Several clinical trials are on-going including testing Remdesivir (anti-viral), Chloroquine and Hydroxychloroquine derivatives (anti-malarial drugs) etc. Unfortunately, each drug has specific limitations. Herein, we review the viral protein involvement to activate ER stress transducers (IRE-1, PERK, ATF-6) and their downstream signals; and evaluate combination therapies for COVID-19 mediated ER stress alterations. Melatonin is an immunoregulator, anti-pyretic, antioxidant, anti-inflammatory and ER stress modulator during viral infections. It enhances protective mechanisms for respiratory tract disorders. Andrographolide, isolated from Andrographis paniculata, has versatile biological activities including immunomodulation and determining SARS-CoV-2 binding site. Considering the properties of both compounds in terms of anti-inflammatory, antioxidant, anti-pyrogenic, anti-viral and ER stress modulation and computational approaches revealing andrographolide docks with the SARS-CoV2 binding site, we predict that this combination therapy may have potential utility against COVID-19.

Causes of Sudden Unexpected Death in Schizophrenia Patients: A Forensic Autopsy Population Study.

BACKGROUND: Schizophrenia is a detrimental psychiatric disorder, with an increased mortality from natural and nonnatural causes. METHODS: This study was a retrospective review of autopsy cases of all the individuals with history of schizophrenia investigated by the Office of the Chief Medical Examiner, State of Maryland, for a 5-year period from 2008 to 2012. RESULT: A total of 391 schizophrenia patients were autopsied at the Office of the Chief Medical Examiner because they died suddenly and unexpectedly. Their age ranged from 15 to 100 years with the mean age of 49.5 years. Of the 391 deaths, 191 (48.8%) were white, 185 (47.3%) were African American, and 15 (3.9%) were either Hispanic or Asian. The male and female ratio was 1.5:1. The majority of deaths (64.2%) were caused by natural diseases, 12.0% deaths were accidents, 11.5% deaths were suicides, and 9.7% deaths were homicides. The manner of death remained undetermined in 38 cases (9.7%). Of the 251 natural deaths, 198 cases (78.9%) were owing to cardiovascular diseases. Cause of death was listed as cardiac arrhythmia in 11 cases. This diagnosis of cardiac arrhythmia was made by exclusion based on death scene investigation, review of medical history, complete autopsy, and toxicological tests. Drug intoxication was the second most common cause of death. CONCLUSIONS: The study shows high fatality caused by cardiovascular diseases and drug intoxication among schizophrenia patients, which calls attention of the medical community to closely monitor the high risk factors of sudden death among schizophrenia patients.

Inflammation, Immunity, and Vaccine Development for the Gastric Pathogen Helicobacter pylori.

It has been over 30 years since a link was established between H. pylori infection of the gastric mucosa and the development of chronic gastric diseases. Research in rodent models supported by data from human tissue demonstrated that the host immune response to H. pylori is limited by host regulatory T cells. Immunization has been shown to induce a potent Th1- and Th17-mediated immune response capable of eradicating or at least significantly reducing the bacterial load of H. pylori in the stomach in small animal models. These results have not translated well to humans. Clinical trials employing many of the strategies used in rodents for oral immunization including the use of a mucosal adjuvant such as Escherichia coli LT or delivery by attenuated enteric bacteria have failed to limit H. pylori infection and have highlighted the potential toxicity of exotoxin-based mucosal adjuvants. A recent study, however, utilizing a recombinant fusion protein of H. pylori urease and the subunit B of E. coli LT, was performed on over 4000 children. Efficacy of over 70% was demonstrated against naturally acquired infection compared to control volunteers one year post-immunization. Efficacy was reduced, but still above 50% at three years. This study provided new insight into the strategies for developing an improved vaccine for widespread use in countries with high infection rates and where gastric cancer (GC) remains one of the most common causes of death due to cancer.

Identification of Cross Talk between FoxM1 and RASSF1A as a Therapeutic Target of Colon Cancer.

Metastatic colorectal cancer (mCRC) is characterized by the expression of cellular oncogenes, the loss of tumor suppressor gene function. Therefore, identifying integrated signaling between onco-suppressor genes may facilitate the development of effective therapy for mCRC. To investigate these pathways we utilized cell lines and patient derived organoid models for analysis of gene/protein expression, gene silencing, overexpression, and immunohistochemical analyses. An inverse relationship in expression of oncogenic FoxM1 and tumor suppressor RASSF1A was observed in various stages of CRC. This inverse correlation was also observed in mCRC cells lines (T84, Colo 205) treated with Akt inhibitor. Inhibition of FoxM1 expression in mCRC cells as well as in our ex vivo model resulted in increased RASSF1A expression. Reduced levels of RASSF1A expression were found in normal cells (RWPE-1, HBEpc, MCF10A, EC) stimulated with exogenous VEGF165. Downregulation of FoxM1 also coincided with increased YAP phosphorylation, indicative of tumor suppression. Conversely, downregulation of RASSF1A coincided with FoxM1 overexpression. These studies have identified for the first time an integrated signaling pathway between FoxM1 and RASSF1A in mCRC progression, which may facilitate the development of novel therapeutic options for advanced colon cancer therapy.

Upregulation of RASSF1A in Colon Cancer by Suppression of Angiogenesis Signaling and Akt Activation.

BACKGROUND/AIMS: Silencing of tumor suppressor genes (TSGs) and promotion of angiogenesis are associated with tumor development and metastasis. However, little is known if angiogenic molecules directly control TSGs and vice versa. METHODS: A regulatory link between angiogenesis and down regulation of TSGs was evaluated using an anti-cancer agent, andrographolide (AGP) in cancer cells, mouse xenograft tissues and patient derived organoids through gene/protein expression, gene silencing, and immunohistochemical analyses. RESULTS: AGP treatment demonstrated significant expression of RASSF1A and PTEN TSGs in colon cancer and other cancer cells, mouse tissues and organoids. Depletion of RASSF1A with siRNA limited cyclin D1 and BAX expression. SiRNA depletion of PTEN, upstream regulator of RASSF1A resulted in a 50% reduction in RASSF1A expression. Histopathological analysis of the AGP treated tumor sections showed significant reduction in vessel size, microvascular density and tumor mitotic index suggesting suppression of angiogenesis. This was corroborated by protein analysis demonstrating significant reductions in angiogenesis signaling pathway molecules VEGF165, FOXM1, and pAkt, but significant elevation of the endogenous angiogenesis inhibitor Tsp-2. Treatment of cells with exogenous VEGF prevented the suppression of angiogenesis signaling by AGP, resulting in sustained expression of pAkt, an upstream down-regulator of RASSF1A. RASSF1A expression remained low in VEGF treated cells despite the addition of AGP. CONCLUSION: Our results demonstrate for the first time that AGP induces RASSF1A expression in colon cancer cells and is dependent on angiogenesis signaling events. Therefore, our research may facilitate novel therapeutic options for advanced colon cancer therapy.

Host response genes associated with nodular gastritis in Helicobacter pylori infection.

BACKGROUND: Chronic Helicobacter pylori infection in children induces lymphoid hyperplasia called nodular gastritis (NG) at the antral gastric mucosa. The aim of this study was to evaluate genes in gastric biopsy on microarray analysis, to identify molecules associated with NG on comparison with NG-negative pediatric corpus tissue and with H. pylori-infected adult tissue with atrophic gastritis (AG). METHODS: Eight pediatric and six adult H. pylori-infected patients, as well as six pediatric and six adult uninfected patients were evaluated. All infected adults had AG. NG was observed in the antrum of all eight pediatric patients and in the corpus of three patients. Adult and uninfected patients were free of NG; that is, only pediatric H. pylori-infected patients had NG. Total RNA was purified from gastric biopsy, and microarray analysis was performed to compare gene expression between groups. The three infected children with NG in both the antrum and corpus were excluded from analysis of corpus samples. RESULTS: The number of genes significantly up- or downregulated (fold change >3, P < 0.01) compared with uninfected controls varied widely: 72 in pediatric antrum, 45 in pediatric corpus, 103 in adult antrum and 71 in adult corpus. Nineteen genes had significantly altered expression in the antrum of NG tissue compared with NG-negative pediatric corpus tissue and adult AG tissue. The CD20 B-cell specific differentiation antigen had the most pronounced increase. Previously described regulators of NG development were not predominantly upregulated in the NG mucosa. CONCLUSIONS: CD20 overexpression may play an important role in lymphoid follicle enlargement and NG.

Identification of Helicobacter pylori and the evolution of an efficacious childhood vaccine to protect against gastritis and peptic ulcer disease.

Establishment of Helicobacter pylori infection as an etiologic agent of peptic ulcer disease and other gastric pathologies marked a revolution in gastroenterology which spurred an enormous interest in gastric physiology and immunology research. The association was soon also demonstrated in children as well. Application of antimicrobial therapies have proven remarkably efficacious in eradicating H. pylori and curing pediatric patients of duodenal ulcers as well as gastritis, negating a lifetime of ineffective therapy and life-threatening disease. Countries with high H. pylori prevalence and where H. pylori associated gastric cancer remains a primary cause of death due to cancer however would benefit from childhood vaccination. Studies in rodents and humans utilizing oral vaccination with bacterial exotoxin adjuvants demonstrated potential for limiting H. pylori colonization in the stomach. Almost 25 y of vaccine research recently culminated in a phase III clinical trial of over 4,000 children aged 6-15 y old to test an oral vaccine consisting of the H. pylori urease B subunit genetically fused to the E. coli heat labile toxin. Vaccination was demonstrated to have an efficacy of over 70%. Vaccination may now serve as an effective strategy to significantly reduce H. pylori associated disease in children throughout the world.

Endoplasmic reticulum stress and IRE-1 signaling cause apoptosis in colon cancer cells in response to andrographolide treatment.

The plant metabolite andrographolide induces cell cycle arrest and apoptosis in cancer cells. The mechanism(s) by which andrographolide induces apoptosis however, have not been elucidated. The present study was performed to determine the molecular events that promote apoptosis in andrographolide treated cells using T84, HCT116 and COLO 205 colon cancer cell lines. Andrographolide was determined to limit colony formation and Ki67 expression, alter nuclear morphology, increase cytoplasmic histone-associated-DNA-fragments, and increase cleaved caspase-3 levels. Andrographolide also induced significantly higher expression of endoplasmic reticulum (ER) stress proteins GRP-78 and IRE-1 by 48 h but not PERK or ATF6. Apoptosis signaling molecules BAX, spliced XBP-1 and CHOP were also significantly increased. Moreover, chemical inhibition of ER stress or IRE-1 depletion with siRNA in andrographolide treated cells significantly limited expression of IRE-1 and CHOP as determined by immunofluorescence staining, real time PCR, or immunobloting. This was accompanied by a decreased BAX/Bcl-2 ratio. Andrographolide significantly promotes cancer cell death compared to normal cells. These data demonstrate that andrographolide associated ER stress contributes to apoptosis through the activation of a pro-apoptotic GRP-78/IRE-1/XBP-1/CHOP signaling pathway.

Early Molecular Events in Murine Gastric Epithelial Cells Mediated by Helicobacter pylori CagA.

BACKGROUND: Murine models of Helicobacter pylori infection are used to study host-pathogen interactions, but lack of severe gastritis in this model has limited its usefulness in studying pathogenesis. We compared the murine gastric epithelial cell line GSM06 to the human gastric epithelial AGS cell line to determine whether similar events occur when cultured with H. pylori. MATERIALS AND METHODS: The lysates of cells infected with H. pylori isolates or an isogenic cagA-deficient mutant were assessed for translocation and phosphorylation of CagA and for activation of stress pathway kinases by immunoblot. RESULTS: Phosphorylated CagA was detected in both cell lines within 60 minutes. Phospho-ERK 1/2 was present within several minutes and distinctly present in GSM06 cells at 60 minutes. Similar results were obtained for phospho-JNK, although the 54 kDa phosphoprotein signal was dominant in AGS, whereas the lower molecular weight band was dominant in GSM06 cells. CONCLUSION: These results demonstrate that early events in H. pylori pathogenesis occur within mouse epithelial cells similar to human cells and therefore support the use of the mouse model for the study of acute CagA-associated host cell responses. These results also indicate that reduced disease in H. pylori-infected mice may be due to lack of the Cag PAI, or by differences in the mouse response downstream of the initial activation events.

Mucosal-Associated Invariant T Cells in the Human Gastric Mucosa and Blood: Role in Helicobacter pylori Infection.

Mucosal-associated invariant T (MAIT) cells represent a class of antimicrobial innate-like T cells that have been characterized in human blood, liver, lungs, and intestine. Here, we investigated, for the first time, the presence of MAIT cells in the stomach of children, adults, and the elderly undergoing routine endoscopy and assessed their reactivity to Helicobacter pylori (H. pylori - Hp), a major gastric pathogen. We observed that MAIT cells are present in the lamina propria compartment of the stomach and display a similar memory phenotype to blood MAIT cells. We then demonstrated that gastric and blood MAIT cells are able to recognize H. pylori. We found that CD8(+) and CD4(-)CD8(-) (double negative) MAIT cell subsets respond to H. pylori-infected macrophages stimulation in a MR-1 restrictive manner by producing cytokines (IFN-γ, TNF-α, IL-17A) and exhibiting cytotoxic activity. Interestingly, we observed that blood MAIT cell frequency in Hp(+ve) individuals was significantly lower than in Hp(-ve) individuals. However, gastric MAIT cell frequency was not significantly different between Hp(+ve) and Hp(-ve) individuals, demonstrating a dichotomy between blood and gastric tissues. Further, we observed that the majority of gastric MAIT cells (>80%) expressed tissue-resident markers (CD69(+) CD103(+)), which were only marginally present on PBMC MAIT cells (<3%), suggesting that gastric MAIT cells are readily available to respond quickly to pathogens. These results contribute important new information to the understanding of MAIT cells function on peripheral and mucosal tissues and its possible implications in the host response to H. pylori.

Current Status and Prospects for a Helicobacter pylori Vaccine.

Helicobacter pylori infection contributes to a variety of gastric diseases. H pylori-associated gastric cancer is diagnosed in advanced stages, and a vaccine against H pylori is desirable in parts of the world where gastric cancer remains a common form of cancer. Some of the strategies of vaccine development used in animals have been tested in several phase 3 clinical trials; these trials have been largely unsuccessful, although H pylori-specific immune responses have been induced. New insights into promoting immunity and overcoming the immunosuppressive nature of H pylori infection are required to improve the efficacy of an H pylori vaccine.

Inflammatory and Immune Activation in Intestinal Myofibroblasts Is Developmentally Regulated.

We previously demonstrated that intestinal myofibroblasts from immature tissue produce excessive IL-8 in response to Escherichia coli lipopolysaccharide (LPS) compared to cells from mature tissue. However, it is unknown whether other cytokines and TLR agonists contribute to this developmentally regulated response. The aim of this study was to further characterize differences in inflammatory signaling in human primary intestinal fibroblasts from fetal (FIF) and infant (IIF) tissue and examine their potential to activate the adaptive immune response in vitro. Cytokine profiles of LPS-stimulated FIF and IIF were assessed by cytokine profile array. IL-8, IL-6, and IL-10 production in response to TLR2, TLR2/6, TLR4, and TLR5 agonists was determined by quantitative ELISA. The potential of activated myofibroblasts to activate adaptive immunity was determined by measuring surface class II MHC expression using flow cytometry. LPS-stimulated FIF produced a distinct proinflammatory cytokine profile consisting of MCP-1, GRO-alpha, IL-6, and IL-8 expression. FIF produced significant IL-8 and IL-6 in response to TLR4 agonist. IIF produced significant levels of IL-8 and IL-6 in the presence of TLR5 and TLR2 agonists. IFN-γ-treated FIF expressed greater HLA-DR levels compared to unstimulated controls and IFN-γ- and LPS-treated IIF. Activated FIF produce a more diverse inflammatory cytokine profile and greater levels of IL-8 and IL-6 in response to TLR4 stimulation compared to IIF. FIF express class II MHC proteins associated with activation of the adaptive immune response. These data suggest that FIF may contribute to bacterial-associated gut inflammation in the immature intestine.

Genetic regulation of MUC1 expression by Helicobacter pylori in gastric cancer cells.

Helicobacter pylori infection of the stomach is associated with the development of gastritis, peptic ulcers, and gastric adenocarcinomas, but the mechanisms are unknown. MUC1 is aberrantly overexpressed by more than 50% of stomach cancers, but its role in carcinogenesis remains to be defined. The current studies were undertaken to identify the genetic mechanisms regulating H. pylori-dependent MUC1 expression by gastric epithelial cells. Treatment of AGS cells with H. pylori increased MUC1 mRNA and protein levels, and augmented MUC1 gene promoter activity, compared with untreated cells. H. pylori increased binding of STAT3 and MUC1 itself to the MUC1 gene promoter within a region containing a STAT3 binding site, and decreased CpG methylation of the MUC1 promoter proximal to the STAT3 binding site, compared with untreated cells. These results suggest that H. pylori upregulates MUC1 expression in gastric cancer cells through STAT3 and CpG hypomethylation.

Vaccinating against Helicobacter pylori in the developing world.

Helicobacter pylori infects more than half the world's population and in developing nations the incidence can be over 90%. The morbidity and mortality associated with H. pylori-associated diseases including ulcers and gastric cancer therefore, disproportionately impact the developing world. Mice have been used extensively to demonstrate the feasibility of developing a vaccine for H. pylori infection, and for testing antigens, routes of immunization, dose, and adjuvants. These successes however, have not translated well in clinical trials. Although there are examples where immune responses have been activated, there are few instances of achieving a reduced bacterial load. In vivo and in vitro analyses in both mice and humans demonstrates that the host responds to H. pylori infection through the activation of immunoregulatory mechanisms designed to suppress the anti-H. pylori response. Improved vaccine efficacy therefore, will require the inclusion of factors that over-ride or re-program these immunoregulatory rersponse mechanisms.

Th1-mediated immunity against Helicobacter pylori can compensate for lack of Th17 cells and can protect mice in the absence of immunization.

Helicobacter pylori (H. pylori) infection can be significantly reduced by immunization in mice. Th17 cells play an essential role in the protective immune response. Th1 immunity has also been demonstrated to play a role in the protective immune response and can compensate in the absence of IL-17. To further address the potential of Th1 immunity, we investigated the efficacy of immunization in mice deficient in IL-23p19, a cytokine that promotes Th17 cell development. We also examined the course of Helicobacter infection in unimmunized mice treated with Th1 promoting cytokine IL-12. C57BL/6, IL-12 p35 KO, and IL-23 p19 KO mice were immunized and challenged with H. pylori. Protective immunity was evaluated by CFU determination and QPCR on gastric biopsies. Gastric and splenic IL-17 and IFNγ levels were determined by PCR or by ELISA. Balb/c mice were infected with H. felis and treated with IL-12 therapy and the resulting gastric bacterial load and inflammatory response were assessed by histologic evaluation. Vaccine induced reductions in bacterial load that were comparable to wild type mice were observed in both IL-12 p35 and IL-23 p19 KO mice. In the absence of IL-23 p19, IL-17 levels remained low but IFNγ levels increased significantly in both immunized challenged and unimmunized/challenged mice. Additionally, treatment of H. felis-infected Balb/c mice with IL-12 resulted in increased gastric inflammation and the eradication of bacteria in most mice. These data suggest that Th1 immunity can compensate for the lack of IL-23 mediated Th17 responses, and that protective Th1 immunity can be induced in the absence of immunization through cytokine therapy of the infected host.