Gut commensal Limosilactobacillus reuteri induces atypical memory-like phenotype in human dendritic cells in vitro.

Memory-like responses in innate immune cells confer nonspecific protection against secondary exposures. A number of microbial agents have been found to induce enhanced or diminished recall responses in innate cells, however, studies investigating the ability of probiotic bacteria to trigger such effects are lacking. Here, we show that priming of human monocytes with a secretome from the gut probiotic bacterium Limosilactobacillus (L.) reuteri induces a mixed secondary response phenotype in monocyte-derived dendritic cells (mo-DCs), with a strong IL-6 and IL-1ß response but low TNFα, IL-23 and IL-27 secretion. Instead, blood DC priming with L. reuteri-secretome resembles a tolerant state upon secondary exposure. A similar pattern was found in conventional and gut-like (retinoic acid exposed) DCs, although retinoic acid hampered TNFα and IL-6 production and enrichment of histone modifications in L. reuteri-secretome primed mo-DC cultures. Further, we show that the memory-like phenotype of mo-DCs, induced by priming stimuli, is important for subsequent T helper (Th) cell differentiation pathways and might determine the inflammatory nature of Th cells. We also show enhanced recall responses characterized by robust inflammatory cytokines and lactate production in the gut-like mo-DCs derived from ß-glucan primed monocytes. Such responses were accompanied with enriched histone modifications at the promoter of genes associated with a trained phenotype in myeloid cells. Altogether, we demonstrate that a gut commensal-derived secretome prompts recall responses in human DCs which differ from that induced by classical training agents such as ß-glucan. Our results could be beneficial for future therapeutic interventions where T cell responses are needed to be modulated.

Antagonising Chromatin Remodelling Activities in the Regulation of Mammalian Ribosomal Transcription.

Ribosomal transcription constitutes the major energy consuming process in cells and is regulated in response to proliferation, differentiation and metabolic conditions by several signalling pathways. These act on the transcription machinery but also on chromatin factors and ncRNA. The many ribosomal gene repeats are organised in a number of different chromatin states; active, poised, pseudosilent and repressed gene repeats. Some of these chromatin states are unique to the 47rRNA gene repeat and do not occur at other locations in the genome, such as the active state organised with the HMG protein UBF whereas other chromatin state are nucleosomal, harbouring both active and inactive histone marks. The number of repeats in a certain state varies on developmental stage and cell type; embryonic cells have more rRNA gene repeats organised in an open chromatin state, which is replaced by heterochromatin during differentiation, establishing different states depending on cell type. The 47S rRNA gene transcription is regulated in different ways depending on stimulus and chromatin state of individual gene repeats. This review will discuss the present knowledge about factors involved, such as chromatin remodelling factors NuRD, NoRC, CSB, B-WICH, histone modifying enzymes and histone chaperones, in altering gene expression and switching chromatin states in proliferation, differentiation, metabolic changes and stress responses.

The chromatin-remodeling complexes B-WICH and NuRD regulate ribosomal transcription in response to glucose.

Regulation of ribosomal transcription is under tight control from environmental stimuli, and this control involves changes in the chromatin structure. The underlying mechanism of how chromatin changes in response to nutrient and energy supply in the cell is still unclear. The chromatin-remodeling complex B-WICH is involved in activating the ribosomal transcription, and we show here that knock down of the B-WICH component WSTF results in cells that do not respond to glucose. The promoter is less accessible, and RNA pol I and its transcription factors SL1/TIF-1B and RRN3/TIF-1A, as well as the proto-oncogene c-MYC and the activating deacetylase SIRT7 do not bind upon glucose stimulation. In contrast, the repressive chromatin state that forms after glucose deprivation is reversible, and RNA pol I factors are recruited. WSTF knock down results in an accumulation of the ATPase CHD4, a component of the NuRD chromatin remodeling complex, which is responsible for establishing a repressive poised state at the promoter. The TTF-1, which binds and affect the binding of the chromatin complexes, is important to control the association of activating chromatin component UBF. We suggest that B-WICH is required to allow for a shift to an active chromatin state upon environmental stimulation, by counteracting the repressive state induced by the NuRD complex.

Decoding colorectal cancer epigenomics.

Colorectal cancer (CRC) is very heterogeneous and presents different types of epigenetic alterations including DNA methylation, histone modifications and microRNAs. These changes are considered as characteristics of various observed clinical phenotypes. Undoubtedly, the discovery of epigenetic pathways with novel epigenetic-related mechanisms constitutes a promising advance in cancer biomarker discovery. In this review, we provide an evidence-based discussing of the current understanding of CRC epigenomics and its role in initiation, epithelial-to-mesenchymal transition and metastasis. We also discuss the recent findings regarding the potential clinical perspectives of these alterations as potent biomarkers for CRC diagnosis, prognosis, and therapy in the era of liquid biopsy.

Helicobacter pylori outer membrane protein Q genotypes and their susceptibility to anti-adhesive phytotherapeutic agents.

OBJECTIVE: Helicobacter pylori is a Gram-negative organism. Its outer membrane protein Q (HopQ) mediates host-pathogen interactions; HopQ genotypes 1 and 2 are found associating with gastroduodenal pathologies. The authors measured the anti-adhesion effects of the extracts of Abelmoschus esculentus, Zingiber officinale, Trachyspermum ammi, Glycyrrhiza glabra, Curcuma longa and Capsicum annum against HopQ genotypes and H. pylori cytotoxin-associated gene A (CagA). METHODS: DNA was extracted by polymerase chain reaction of the HopQ genotypes (i.e., type 1, type 2 and CagA) from 115 H. pylori strains. The effect of the extracts from selected dietary ingredients was determined using a gastric adenocarcinoma cell line and a quantitative DNA fragmentation assay. The anti-adhesive effect of these extracts on H. pylori was tested using an anti-adhesion analysis. RESULTS: C. annum, C. longa and A. esculentus showed prominent anti-adhesion effects with resultant values of 17.3% ± 2.9%, 14.6% ± 3.7%, 13.8% ± 3.6%, respectively, against HopQ type 1 and 13.1% ± 1.7%, 12.1% ± 2%, 11.1% ± 1.6%, respectively, against HopQ type 2. C. longa (93%), C. annum (89%) and A. esculentus (75%) had better anti-adhesive activity against H. pylori with HopQ type 1 compared to HopQ type 2 with respective values of 70%, 64% and 51%. Extracts of C. annum (14.7% ± 4.1%), A. esculentus (12.3% ± 4.1%) and Z. officinale (8.4% ± 2.8%) had an anti-adhesion effect against CagA-positive H. pylori strains compared to CagA-negative strains. CONCLUSION: The anti-adhesion properties of the tested phytotherapeutic dietary ingredients were varied with HopQ genotypes. HopQ type 1 was found to be more sensitive to extracts of C. annum, C. longa and A. esculentus compared to the HopQ type 2 genotype.

Cytokine changes in gastric and colonic epithelial cell in response to Planta ovata extract.

Background Psyllium (Planta ovata, Ispaghul) seed and husk are used for treatment of altered bowel habit, i. e. constipation and diarrhea. We studied the effect of Ispaghul extract on secretion of interleukin-1 beta (IL-1ß) by AGS (ATCC CRL 1739) and SW480 (ATCC CCL-227) epithelial cell lines and determined whether Ispaghul extract has an effect on IL-1ß secretion by Helicobacter pylori (H. pylori)-stimulated AGS cell and Escherichia coli K-12 (E. coli K-12)-stimulated SW480 cells in vitro. Methods The AGS cells and SW480 cells were pretreated with Ispaghul extract in concentrations, i. e. 3.5 and 7 µg/mL prior to infection with H. pylori and E. coli K-12. Results DNA fragmentation in AGS and SW480 cells treated with Ispaghul extract was not significant (2.3±0.8 %) compared with untreated cells (2.2±0.6 %). Ispaghul extract decreased the H. pylori-stimulated secretion of IL-1ß by AGS cell (p<0.0001). This effect did not increase as the concentration of extract was increased. Ispaghul extract also decreased E. coli K-12-stimulated IL-1ß secretion by SW480 cell (p<0.0001). This effect increased as the concentration of extracts was increased. Conclusions Ispaghul extract had an effect on stimulated secretion of IL-1ß by the AGS and SW480 cell. It decreased pro-inflammatory reaction from both cell lines stimulated by bacteria.

Sporadic Early Onset Colorectal Cancer in Pakistan: a Case- Control Analysis of Microsatellite Instability.

BACKGROUND: Early onset sporadic colorectal cancer (CRC) is a biologically and clinically distinct entity hypothesized to exhibit differences in histological features and microsatellite instability (MSI) as compared to typical onset CRC. This study compared the MSI status, mismatch repair enzyme deficiency and clinicopathological features of early onset (aged ≤45 years) with controls (>45 years). MATERIALS AND METHODS: A total of 30 cases and 30 controls were analyzed for MSI status using the Bethesda marker panel. Using antibodies against hMLH1, hMSH2 and hMSH6, mismatch repair protein expression was assessed by immunohistochemistry. Molecular characteristics were correlated with clinicopathological features. RESULTS: The early onset sporadic CRCs were significantly more poorly differentiated tumors, with higher N2 nodal involvement and greater frequency of signet ring phenotype than the typical onset cases. MSI was observed in 18/30 cases, with 12/18 designated as MSI-high (MSI-H) and 6/18 designated as MSI-low (MSI-L). In the control group, 14 patients exhibited MSI, with 7 MSI-H and 7 MSI-L. MSI tumors in both cases and controls exhibited loss of hMLH1, hMSH2 and hMSH6. MSS tumors did not exhibit loss of expression of MMR proteins, except hMLH1 protein in 3 controls. No statistically significant difference was noted in MSI status or expression of MMR proteins in cases versus controls. CONCLUSIONS: Microsatellite status is comparable between early and typical onset sporadic CRC patients in Pakistan suggesting that differences in clinicopathological features between these two subsets are attributable to other molecular mechanisms.

Colorectal cancer carcinogenesis: a review of mechanisms.

Colorectal cancer (CRC) is the second most common cancer in women and the third most common in men globally. CRC arises from one or a combination of chromosomal instability, CpG island methylator phenotype, and microsatellite instability. Genetic instability is usually caused by aneuploidy and loss of heterozygosity. Mutations in the tumor suppressor or cell cycle genes may also lead to cellular transformation. Similarly, epigenetic and/or genetic alterations resulting in impaired cellular pathways, such as DNA repair mechanism, may lead to microsatellite instability and mutator phenotype. Non-coding RNAs, more importantly microRNAs and long non-coding RNAs have also been implicated at various CRC stages. Understanding the specific mechanisms of tumorigenesis and the underlying genetic and epigenetic traits is critical in comprehending the disease phenotype. This paper reviews these mechanisms along with the roles of various non-coding RNAs in CRCs.

Exposure assessment of lead from food and airborne dusts and biomonitoring in pregnant mothers, their fetus and siblings in Karachi, Pakistan and Shimotsuke, Japan.

AIM: Exposure assessment of lead (Pb) and Arsenic (As) from food, water, and house dust intake were assessed among pregnant women, their children and fetuses in Pakistan and Japan, as well as their body burden of the metals in their blood. METHOD: Fifty families which included a pregnant woman, a fetus and the 1-3-year-old siblings were recruited in Karachi and Khairpur in Pakistan, and Shimotsuke and Asahikawa in Japan, respectively. Their dietary exposure to Pb and As was measured in 3-day food duplicates and drinking water by ICP-MP. Pb in house dust and respirable dust was evaluated with an energy dispersive X-ray fluorescence spectrometry. Non-radioactive isotope Pb profiles of blood specimens will be compared with those of the exposure origins, such as food duplicates, respirable house dust, the soils nearby, and gasoline. RESULTS: Judging from the data collected and analyzed so far, contribution from dietary intake is highly correlated to higher body burden of Pb among Pakistani mothers. Additional data analyses will reveal the status of Pb and As body burden in Pakistani mothers, fetuses and their siblings, and causal sources of high body burden is delineated by Pb isotope profile analysis of different sources of Pb exposure.

Immunomodulatory Effects of Psyllium Extract on Helicobacter pylori Interaction With Gastric Epithelial Cells.

Natural plant product Psyllium has anti-inflammatory activity that can modulate the function of cytokines. We determined the effect of Psyllium husk extract on interleukin (IL)-8 and NF-κB secretion by gastric epithelial cells in response to Helicobacter pylori Human gastric adenocarcinoma cell line (AGS) cells were pretreated with Psyllium extract in different concentrations before H pylori infection. Cell culture supernatant was analyzed for IL-8 and NF-κB by ELISA. RNA from cells was used for real-time polymerase chain reaction for messenger RNA expression of IL-8. Psyllium extract 5 and 10 µg/mL markedly (P < .001) lowered basal IL-8 by 64.71% and 74.51%, respectively, and H pylori-stimulated IL-8 was also (P < .001) lowered by 41.67% and 66.67%, respectively. Psyllium 5 and 10 µg/mL also reduced (P < .0001) cagA-positive H pylori-induced IL-8 mRNA expression by 42.3% and 67.6%, respectively. Psyllium also reduced (P = .0001) NF-κB in response to H pylori strains confirming its role as an anti-inflammatory agent.