Exposure to diethylstilbestrol during pregnancy modulates microRNA expression profile in mothers and fetuses reflecting oncogenic and immunological changes

Prenatal exposure to diethylstilbestrol (DES) is known to cause an increased susceptibility to a wide array of clinical disorders in humans. Previous studies from our laboratory demonstrated that prenatal exposure to DES induces thymic atrophy and apoptosis in the thymus. In the current study, we investigated if such effects on the thymus result from alterations in the expression of microRNA (miR). To that end, pregnant C57BL/6 mice who were exposed to DES and miR profiles in thymocytes of both the mother and fetuses on postnatal day 3 (gestation day 17) were studied. Of the 609 mouse miRs examined, we noted 59 altered miRs that were common for both mothers and fetuses, whereas 107 altered miRs were specific to mothers only and 101 altered miRs were specific to fetuses only. Upon further analyses in the fetuses, we observed that DES-mediated changes in miR expression may regulate genes involved in important functions, such as apoptosis, autophagy, toxicity, and cancer. Of the miRs that showed decreased expression following DES treatment, miR-18b and miR-23a were found to possess complementary sequences and binding affinity for 3' untranslated regions of the Fas ligand (FasL) and Fas, respectively. Transfection studies confirmed that DES-mediated downregulation of miR-18b and miR-23a led to increased FasL and Fas expression. These data demonstrated that prenatal DES exposure can cause alterations in miRs, leading to changes in the gene expression, specifically, miR-mediated increased expression in FasL and Fas causing apoptosis and thymic atrophy.

Single Nucleotide Polymorphisms in IL-10, IL-12p40, and IL-13 Genes and Susceptibility to Glioma

Glioma is one of the most aggressive and most common tumors of the central nervous system (CNS) in humans. The exact causes of glioma are not well known, but evidence suggests the involvement of genetic factors in addition to environmental risk factors. The present study aimed to determine whether polymorphisms in IL-10-1082A/G, IL-12p40 1188C/A, and IL-13+2044G/A (rs20541) are associated with the incidence of glioma in Iraqi patients. Ninety-six patients with different grades of glioma and 40 apparently healthy individuals were recruited. A blood sample and genomic DNA were collected from all subjects. The amplification refractory mutation system and sequence-specific primer polymerase chain reaction (PCR) were used for genotyping of IL-10-1082A/G and IL-12p40 1188C/A, respectively; whereas, the IL-13+2044G/A was detected by DNA sequencing after amplification of the genes by PCR. All SNPs were within Hardy-Weinberg equilibrium and each appeared in three genotypes in patients and controls. In IL-10-1082A/G, these genotypes frequencies were AA (75%), AG (22.93%) and GG (2.07%) in patients as compared to similar frequencies (62.5%), (27.5%) and (10%) respectively, in controls. The variant IL-12p40 1188C/A genotype was AA (72.92%), AC (23.96%), and CC (3.13%%) in patients as compared to 65%, 30%, and 5%, respectively, in controls. The frequencies of IL-13+2044G/A genotypes (GG, GA, and AA) were 89.58%, 9.37%, and 1.04% among patients versus 47.5%, 32.5% and 20%, respectively, among controls. These results suggest a protective role of mutant alleles G and A in IL-10-1082A/G and IL-13+2044G/A against gliomas. Further studies with more rigorous parameter designs will be needed to confirm the current findings.

Mononuclear iron(iii) complexes of tridentate ligands with efficient nuclease activity and studies of their cytotoxicity

Mono- and bis-chelated iron(iii) complexes derived from phenolato-based tridentate ligands have been synthesised and characterized. These complexes show electrostatic DNA interactions and efficient DNA cleavage via OH˙ radicals, and induce cytotoxicity in MCF7 cell lines.

Supramolecular assemblies of benzene-1,3,5-tricarboxylic acid and 3,5-substituted pyrazoles: formation and structural analysis

Reaction of benzene-1,3,5-tricarboxylic acid (H3BTC) with various 3,5-substituted pyrazoles resulted in different host guest assemblies. Theoretical calculations were used to calculate the interaction energy and their comparison with the experimental data obtained through thermogravimetric analysis.

miR-155 deficiency protects mice from experimental colitis by reducing T helper type 1/type 17 responses

Inflammatory bowel disease (IBD), a chronic intestinal inflammatory condition that affects millions of people worldwide, results in high morbidity and exorbitant health-care costs. The critical features of both innate and adaptive immunity are to control inflammation and dysfunction in this equilibrium is believed to be the reason for the development of IBD. miR-155, a microRNA, is up-regulated in various inflammatory disease states, including IBD, and is a positive regulator of T-cell responses. To date, no reports have defined a function for miR-155 with regard to cellular responses in IBD. Using an acute experimental colitis model, we found that miR-155(-/-) mice, as compared to wild-type control mice, have decreased clinical scores, a reversal of colitis-associated pathogenesis, and reduced systemic and mucosal inflammatory cytokines. The increased frequency of CD4+ lymphocytes in the spleen and lamina propria with dextran sodium sulphate induction was decreased in miR-155(-/-) mice. Similarly, miR-155 deficiency abrogated the increased numbers of interferon-γ expressing CD4+ T cells typically observed in wild-type mice in this model. The frequency of systemic and mucosal T helper type 17-, CCR9-expressing CD4+ T cells was also reduced in miR-155(-/-) mice compared with control mice. These findings strongly support a role for miR-155 in facilitating pro-inflammatory cellular responses in this model of IBD. Loss of miR-155 also results in decreases in T helper type 1/type 17, CD11b+) and CD11c+ cells, which correlated with reduced clinical scores and severity of disease. miR-155 may serve as a potential therapeutic target for the treatment of IBD.

Exercise effects on polyp burden and immune markers in the ApcMin/+ mouse model of intestinal tumorigenesis

Many observational epidemiologic studies suggest an association between exercise and colon cancer risk. The mechanisms contributing to a preventative effect of exercise on colon cancer are complex and multifaceted. Altered immune system function is one possible mechanism that has been largely unexplored. Therefore, the purpose of this study was to examine the effects of exercise on markers associated with macrophages and select T cell populations in a mouse model of intestinal tumorigenesis and to relate this to polyp characteristics. Male Apc^Min/+ mice were randomly assigned to either sedentary (Sed) or exercise (Ex) treatment (n=6–9/group). The exercise treatment consisted of treadmill running for 1 h/day and 6 days a week at 15 m/min from 4 until 16 weeks of age. Intestinal polyps were counted and categorized by size. Mucosal tissue was analyzed for mRNA expression of overall macrophages (F4/80), for genes associated with M1 (IL-12, IL-23 and Nos2) and M2 (CD206, IL-10, IL-4, CCL17, CCL22 and Arg-1) macrophages and the macrophage chemoattractants MCP-1, fetuin A and CXCL14. Markers for cytotoxic T cells (CTLs) and regulatory T cells were also examined by measuring mRNA expression of CD8 and Foxp3, respectively. While there was no significant difference in overall polyp number between the groups (Sed, 23.3±4.3; and Ex, 16.5±4.3), Ex did have a reduction in the number of large polyps (Sed, 6.1±1.1; and Ex, 3.0±0.6) (P<0.05). This was consistent with a decrease in spleen weight (P<0.05). Similarly, Ex reduced mRNA expression of overall macrophages (F4/80) as well as markers associated with both M1 (IL-12) and M2 (CD206, CCL22 and Arg-1) subtypes (P<0.05) but there was no significant decrease in macrophage chemoattractants. CD8 expression was increased while Foxp3 expression was decreased with Ex (P<0.05). Overall the data provide important new information on immune regulation as a possible mechanism for the documented benefits of exercise training on reducing colon cancer progression.

Role of microRNAs in resveratrol-mediated mitigation of colitis-associated tumorigenesis in Apc(Min/+) mice

The pleiotropic effects of resveratrol include anti-inflammatory, antioxidant, and anticancer activities, and thus unique possibilities exist to explore mechanistic pathways of chemoprevention. The aim of this study was to investigate the role of microRNA (miRNA) alterations induced by resveratrol in the context of chemopreventive mechanisms against dextran sodium sulfate (DSS)-induced colitis-associated tumorigenesis in the Apc(Min/+) mouse. To that end, Apc(Min/+) mice were exposed to 2% DSS to enhance intestinal inflammation and polyp development. Concurrently, mice received either vehicle or resveratrol treatment via oral gavage for 5 weeks. Interestingly, treatment of DSS-exposed mice with resveratrol resulted in decreased number and size of polyps, fewer histologic signs of cell damage, and decreased proliferating epithelial cells in intestinal mucosa compared with vehicle. Resveratrol treatment dramatically reversed the effects of DSS on the numbers of specific inflammatory CD4(+) T cells, CD8(+) T cells, B cells, natural killer T cells, and myeloid-derived suppressor cells in mesenteric lymph nodes. Resveratrol treatment also decreased interleukin-6 (IL-6) and tumor necrosis factor-α protein levels and reduced IL-6 and cyclooxygenase-2 mRNA expression. Microarray analysis revealed 104 miRNAs exhibiting >1.5-fold differences in expression in the intestinal tissue of resveratrol-treated mice. Among them, two miRNAs with anti-inflammatory properties, miRNA-101b and miRNA-455, were validated to be upregulated with resveratrol treatment by reverse-transcription polymerase chain reaction. Pathway analysis revealed that numerous differentially regulated miRNAs targeted mRNAs associated with inflammatory processes with known roles in intestinal tumorigenesis. These results suggest that resveratrol mediates anti-inflammatory properties and suppresses intestinal tumorigenesis through miRNA modulation.

Comparative study of seasonal variation in bacterial flora concomitant with farm raised fingerlings of Cyprinus carpio at tarai region of Uttarakhand

The bacterial infection is an important economic and limiting factor in intensive fish production. The present study focuses on investigation of the bacterial population associated with farmed common carp fingerlings, its environment and limnological quality of pond, during winter and summer season. It was found that the bacterial count in the pond sediment (6.40 cfu x 10(4)) was about 10 times higher in comparison of pond water (6.93 cfu x 10(3)). Further, the intestinal bacterial count was about 100 times higher (6.67 cfu x 10(5)) during winter and 1000 times higher (2.33 cfu x 10(6)) during summer season in comparison to the surfacial skin of fish during winter and summer (3.39 and 8.87 cfu x 10(3)), respectively. The isolated bacteria were both Gram negative and Gram positive, mostly aerobic rods. Furthermore, the temperature showed a significant relation with the bacterial counts of pond water. In the summer season, higher bacterial counts (8.72 cfu x 10(3)) were recorded as compared to winter (5.13 cfu x 10(3)). The dominant bacteria isolated from the sample of pond water, pond sediment and fish were identified as Aeromonas hydrophila, Pseudomonas fluorescens, Pseudomonas sp., Flavobacter sp., Bacillus sp., Micrococcus sp., Corynebacterium sp. Moreover, the bacterial density was dependent on C:N values, and the optimum range of C: N ratio was found between 16-23, for the carp culture ponds. Among the isolated bacterial flora, the presence of strains which were well known for their probiotic properties suggested an autochthonous source for use in aquaculture. Further, analysis of various physico-chemical parameters of pond water revealed that they were within the suitable range for the freshwater fish culture throughout farming phase.

Nonlinear growth kinetics of breast cancer stem cells: implications for cancer stem cell targeted therapy

Cancer stem cells (CSCs) have been identified in primary breast cancer tissues and cell lines. The CSC population varies widely among cancerous tissues and cell lines, and is often associated with aggressive breast cancers. Despite of intensive research, how the CSC population is regulated within a tumor is still not well understood so far. In this paper, we present a mathematical model to explore the growth kinetics of CSC population both in vitro and in vivo. Our mathematical models and supporting experiments suggest that there exist non-linear growth kinetics of CSCs and negative feedback mechanisms to control the balance between the population of CSCs and that of non-stem cancer cells. The model predictions can help us explain a few long-standing questions in the field of cancer stem cell research, and can be potentially used to predict the efficicacy of anti-cancer therapy.

The emerging role of leptin antagonist as potential therapeutic option for inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic relapsing immune-mediated inflammatory disorder that affects millions of people around the world. Leptin is a satiety hormone produced primarily by adipose tissue and acts both centrally and peripherally. Leptin has been shown to play a major role in regulating metabolism, which increases during IBD progression. Leptin mediates several physiological functions including elevated blood pressure, tumorogenesis, cardiovascular pathologies and enhanced immune response in many autoimmune diseases. Recent development of a leptin mutant antagonist that blocks leptin activity raises great hope and opens up new possibilities for therapy in many autoimmune diseases including IBD. To this end, preliminary data from an ongoing study in our laboratory on pegylated leptin antagonist mutant L39A/D40A/F41A (PEG-MLA) treatment shows an inhibition of chronic colitis in IL-10-/- mice. PEG-MLA effectively attenuates the overall clinical scores, reverses colitis-associated pathogenesis including a decrease in body weight, and decreases systemic leptin level. PEG-MLA induces both central and peripheral leptin deficiency by mediating the cellular immune response. In summary, after blocking leptin activity, the correlative outcome between leptin-mediated cellular immune response, systemic leptin levels, and amount of adipose tissue together may provide new strategies for therapeutic intervention in autoimmune diseases, especially for intestinal inflammation.

Impact of single nucleotide polymorphism in IL-4, IL-4R genes and systemic concentration of IL-4 on the incidence of glioma in Iraqi patients

Glioma is the most common and believed to be one of the most aggressive tumors of the central nervous system (CNS) in humans. Very little information is available on the etiology and pathogenesis of these tumors to date. A significant gap remains in our current understanding of the molecular pathways involved in the genesis, progression and clinical behavior of these tumors. Recently, several single nucleotide polymorphisms (SNPs) have been identified in cytokine gene sequences, particularly within the promoter region of these genes, and have been shown to be associated with the development of different types of brain tumors. The present study investigates the association of C-33T SNP in the interleukin-4 (IL-4) gene with systemic IL-4 level and the S503P SNP in the IL-4R gene with the incidence of glioma. Blood samples were collected from 100 histologically confirmed adult patients with glioma, and 30 apparently healthy individuals from the same area. DNA was extracted from each blood sample, and the IL-4 and IL-4R genes were amplified using polymerase chain reaction (PCR) with gene-specific primers. Systemic IL-4 concentration was assessed in serum samples from each participant by enzyme-linked immunosorbent assay (ELISA). We observed a negative association between the homozygous genotype (CC) of the SNP C-33T of the IL-4 gene with the incidence of glioma (OR=0.19, 95% CI=0.035-1.02), while the T allele of the SNP demonstrated a significant protective association against glioma. Similarly, the heterozygous (CT) and homozygous mutant (CC) of the SNP S503P of the IL-4R gene demonstrated a significant association with glioma development (OR=0.405, 95% CI=0.17-0.969 and OR=0.147, 95% CI=0.036-0.6 respectively), while the C allele exhibited a highly significant association with protection from glioma formation. These findings suggest that the T allele of the SNP C-33T in the IL-4 gene and the C allele of the SNP S503P in IL-4R may have a protective role against glioma development.

Leptin antagonist ameliorates chronic colitis in IL-10⁻/⁻ mice

BACKGROUND

Although the etiology of two major forms of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC) are unknown and evidence suggests that chronic intestinal inflammation is caused by an excessive immune response to mucosal antigens. Previous studies support the role for TGF-β1 through 3 in the initiation and maintenance of tolerance via the induction of regulatory T cells (Tregs) to control intestinal inflammation. Leptin, a satiety hormone produced primarily by adipose tissue, has been shown to increase during colitis progression and is believed to contribute to disease genesis and/or progression.

AIM

We investigated the ability of a pegylated leptin antagonist (PG-MLA) to ameliorate the development of chronic experimental colitis.

RESULTS

Compared to vehicle control animals, PG-MLA treatment of mice resulted in an (1) attenuated clinical score; (2) reversed colitis-associated pathogenesis including a decrease in body weight; (3) reduced systemic and mucosal inflammatory cytokine expression; (4) increased insulin levels and (5) enhanced systemic and mucosal Tregs and CD39⁺ Tregs in mice with chronic colitis. The percentage of systemic and mucosal TGF-β1, -β2 and -β3 expressing CD4⁺ T cells were augmented after PG-MLA treatment. The activation of STAT1 and STAT3 and the expression of Smad7 were also reduced after PG-MLA treatment in the colitic mice. These findings clearly suggest that PG-MLA treatment reduces intestinal Smad7 expression, restores TGF-β1-3 signaling and reduces STAT1/STAT3 activation that may increase the number of Tregs to ameliorate chronic colitis.

CONCLUSION

This study clearly links inflammation with the metabolic hormone leptin suggesting that nutritional status influences immune tolerance through the induction of functional Tregs. Inhibiting leptin activity through PG-MLA might provide a new and novel therapeutic strategy for the treatment of IBD.

The severity of experimental autoimmune cystitis can be ameliorated by anti-CXCL10 Ab treatment

Background

Interstitial cystitis (IC), more recently called painful bladder syndrome (PBS) is a complex disease associated with chronic bladder inflammation that primarily affects women. Its symptoms include frequent urinary urgency accompanied by discomfort or pain in the bladder and lower abdomen. In the United States, eight million people, mostly women, have IC/PBS. New evidence that autoimmune mechanisms are important in the pathogenesis of IC/PBS triggered interest.

Methodology/Principal Findings

SWXJ mice immunized with a homogenate of similar mice’s urinary bladders develop an autoimmune phenotype comparable to clinical IC with functional and histological alterations confined to the urinary bladder. Using the murine model of experimental autoimmune cystitis (EAC), we found that serum levels of CXCR3 ligand and local T helper type 1 (Th1) cytokine are elevated. Also, IFN-γ-inducible protein10 (CXCL10) blockade attenuated overall cystitis severity scores; reversed the development of IC; decreased local production of CXCR3 and its ligands, IFN-γ, and tumor necrosis factor-α (TNF-α); and lowered systemic levels of CXCR3 ligands. Urinary bladder CD4⁺ T cells, mast cells, and neutrophils infiltrates were reduced following anti-CXCL10 antibody (Ab) treatment of mice. Anti-CXCL10 Ab treatment also reversed the upregulated level of CXCR3 ligand mRNA at urinary bladder sites. The decreased number and percentage of systemic CD4⁺ T cells in EAC mice returned to normal after anti-CXCL10 Ab treatment.

Conclusion/Significance

Taken together, our findings provide important new information about the mechanisms underlying EAC pathogenesis, which has symptoms similar to those of IC/PBS. CXCL10 has the potential for use in developing new therapy for IC/PBS.

Distinct microRNA expression profile and targeted biological pathways in functional myeloid-derived suppressor cells induced by Δ9-tetrahydrocannabinol in vivo: regulation of CCAAT/enhancer-binding protein α by microRNA-690

Δ(9)-Tetrahydrocannabinol (THC), the major bioactive component of marijuana, has been shown to induce functional myeloid-derived suppressor cells (MDSCs) in vivo. Here, we studied the involvement of microRNA (miRNA) in this process. CD11b(+)Gr-1(+) MDSCs were purified from peritoneal exudates of mice administered with THC and used for genome-wide miRNA profiling. Expression of CD31 and Ki-67 confirmed that the THC-MDSCs were immature and proliferating. THC-induced MDSCs exhibited distinct miRNA expression signature relative to various myeloid cells and BM precursors. We identified 13 differentially expressed (>2-fold) miRNA in THC-MDSCs relative to control BM precursors. In silico target prediction for these miRNA and pathway analysis using multiple bioinformatics tools revealed significant overrepresentation of Gene Ontology clusters within hematopoiesis, myeloid cell differentiation, and regulation categories. Insulin-like growth factor 1 signaling involved in cell growth and proliferation, and myeloid differentiation pathways were among the most significantly enriched canonical pathways. Among the differentially expressed, miRNA-690 was highly overexpressed in THC-MDSCs (∼16-fold). Transcription factor CCAAT/enhancer-binding protein α (C/EBPα) was identified as a potential functional target of miR-690. Supporting this, C/EBPα expression was attenuated in THC-MDSCs as compared with BM precursors and exhibited an inverse relation with miR-690. miR-690 knockdown using peptide nucleic acid-antagomiR was able to unblock and significantly increase C/EBPα expression establishing the functional link. Further, CD11b(+)Ly6G(+)Ly6C(+) and CD11b(+)Ly6G(-)Ly6C(+) purified subtypes showed high levels of miR-690 with attenuated C/EBPα expression. Moreover, EL-4 tumor-elicited MDSCs showed increased miR-690 expression. In conclusion, miRNA are significantly altered during the generation of functional MDSC from BM. Select miRNA such as miR-690 targeting genes involved in myeloid expansion and differentiation likely play crucial roles in this process and therefore in cannabinoid-induced immunosuppression.

Linking obesity to colorectal cancer: recent insights into plausible biological mechanisms

PURPOSE OF REVIEW

This review will examine the recent scientific literature on the mechanisms that are thought to link obesity to colorectal cancer (CRC) risk.

RECENT FINDINGS

Obesity has emerged as a leading environmental risk factor for the development of CRC. However, the mechanisms underlying this relationship have not yet been fully elucidated. Recent literature has focused on inflammatory processes, adipokines, and estrogen. Obesity-enhanced inflammation is largely orchestrated by increases in adipose tissue macrophages leading to the secretion of inflammatory cytokines including tumor necrosis factor-α, monocyte chemoattractant protein-1, and interleukin-6, all of which are linked to CRC. Adiponectin is decreased with obesity and has been reported to be negatively associated with CRC, whereas leptin, which is increased, is positively associated with the disease. Estrogen has been shown to influence CRC, although its role remains controversial; some studies have implicated estrogen as being protective, whereas others have suggested it to be a risk factor. We highlight the most important recent advances that have been made on the aforementioned mechanisms that are thought to link obesity to CRC.

SUMMARY

A better understanding of the mechanisms linking obesity to CRC risk is necessary for the design of effective treatment approaches in future clinical trials.