No abstract

We investigated the role of the NFE2L3 transcription factor in inflammation-induced colorectal cancer. Our studies revealed that Nfe2l3−/− mice exhibit significantly less inflammation in the colon, reduced tumor size and numbers, and skewed localization of tumors with a more pronounced decrease of tumors in the distal colon. CIBERSORT analysis of RNA-seq data from normal and tumor tissue predicted a reduction in mast cells in Nfe2l3−/− animals, which was confirmed by toluidine blue staining. Concomitantly, the transcript levels of Il33 and Rab27a, both important regulators of mast cells, were reduced and increased, respectively, in the colorectal tumors of Nfe2l3−/− mice. Furthermore, we validated NFE2L3 binding to the regulatory sequences of the IL33 and RAB27A loci in human colorectal carcinoma cells. Using digital spatial profiling, we found that Nfe2l3−/− mice presented elevated FOXP3 and immune checkpoint markers CTLA4, TIM3, and LAG3, suggesting an increase in Treg counts. Staining for CD3 and FOXP3 confirmed a significant increase in immunosuppressive Tregs in the colon of Nfe2l3−/− animals. Also, Human Microbiome Project (HMP2) data showed that NFE2L3 transcript levels are higher in the rectum of ulcerative colitis patients. The observed changes in the tumor microenvironment provide new insights into the molecular differences regarding colon cancer sidedness. This may be exploited for the treatment of early-onset colorectal cancer as this emerging subtype primarily displays distal/left-sided tumors.

Background: Epigenetic dysregulation has been proposed as a key mechanism for arsenic-related cardiovascular disease (CVD). We evaluated differentially methylated positions (DMPs) as potential mediators on the association between arsenic and CVD. Methods: Blood DNA methylation was measured in 2321 participants (mean age 56.2, 58.6% women) of the Strong Heart Study, a prospective cohort of American Indians. Urinary arsenic species were measured using high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry. We identified DMPs that are potential mediators between arsenic and CVD. In a cross-species analysis, we compared those DMPs with differential liver DNA methylation following early-life arsenic exposure in the apoE knockout (apoE −/− ) mouse model of atherosclerosis. Results: A total of 20 and 13 DMPs were potential mediators for CVD incidence and mortality, respectively, several of them annotated to genes related to diabetes. Eleven of these DMPs were similarly associated with incident CVD in 3 diverse prospective cohorts (Framingham Heart Study, Women’s Health Initiative, and Multi-Ethnic Study of Atherosclerosis). In the mouse model, differentially methylated regions in 20 of those genes and DMPs in 10 genes were associated with arsenic. Conclusions: Differential DNA methylation might be part of the biological link between arsenic and CVD. The gene functions suggest that diabetes might represent a relevant mechanism for arsenic-related cardiovascular risk in populations with a high burden of diabetes.

BACKGROUND: Epidemiologic studies indicate that early life arsenic exposures are linked to an increased risk of cardiovascular diseases. Different oxidation and methylation states of arsenic exist in the environment and are formed in vivo via the action of arsenic (+3 oxidation state) methyltransferase (As3MT). Methylated arsenicals are pro-atherogenic postnatally, but pre-and perinatal effects are unclear. This is particularly important because methylated arsenicals are known to cross the placenta. OBJECTIVES: We tested the effects of early life exposure to inorganic and methylated arsenicals on atherosclerotic plaque formation and its composition in apolipoprotein E knock-out (apoE −= − ) mice and evaluated whether apoE −= − mice lacking As3MT expression were susceptible to this effect. METHODS: We exposed apoE −= − or apoE −= − =As3MT −= − mice to 200 ppb inorganic or methylated arsenic in the drinking water from conception to weaning and assessed atherosclerotic plaques in the offspring at 18 wk of age. Mixed regression models were used to estimate the mean difference in each outcome relative to controls, adjusting for sex and including a random effects term to account for within-litter clustering. RESULTS: Early life exposure to inorganic arsenic, and more profoundly methylated arsenicals, resulted in significantly larger plaques in the aortic arch and sinus in both sexes. Lipid levels in these plaques were higher without a substantial difference in macrophage numbers. Smooth muscle cell content was not altered, but collagen content was lower. Importantly, there were sex-specific differences in these observations, where males had higher lipids and lower collagen in the plaque, but females did not. In mice lacking As3MT, arsenic did not alter the plaque size, although the size was highly variable. In addition, control apoE −= − =As3MT −= − mice had significantly larger plaque size compared with control apoE −= − . CONCLUSION: This study shows that early life exposure to inorganic and methylated arsenicals is pro-atherogenic with sex-specific differences in plaque composition and a potential role for As3MT in mice.

Arsenic exposure is correlated with atherosclerosis in epidemiological studies and in animal models. We have previously shown that arsenic exposure enhanced atherosclerotic plaque size, increased plaque lipid content and decreased plaque smooth muscle cell and collagen contents in apoE-/- mice. However, the percentage of plaque-resident macrophages, the primary drivers of atherosclerosis remained unchanged. Therefore, we hypothesized that while arsenic does not change the quantity of macrophages, it alters macrophage transcriptome towards a pro-atherogenic state. To test this hypothesis, we used bone marrow-derived macrophages, polarized them to either IFN-ɣ stimulated, pro-inflammatory or IL-4 stimulated, alternatively-activated macrophages in the presence or absence of 0.67 µM (50 ppb) arsenic and performed RNA sequencing. Arsenic exposure altered the gene expression of the macrophages in a subtype-specific manner. Most differentially expressed genes (88%) were altered specifically in either IFN-ɣ- or IL-4-stimulated macrophages, while in the remaining 12% genes that changed in both cell types, did so in opposite directions. In IL-4-stimulated macrophages, arsenic significantly downregulated the genes involved in cholesterol biosynthesis and the chemokines, CCL17/CCL22. Whereas, in IFN-ɣ-stimulated macrophages, genes associated with liver X receptor (LXR) pathway were downregulated by arsenic. Using a bone marrow transplant experiment, we validated that deletion of LXRα from the hematopoietic compartment rescued arsenic-enhanced atherosclerosis in apoE-/- mouse model. Together, these data suggest that arsenic modulates subtype-specific transcriptomic changes in macrophages and further emphasize the need to define macrophage heterogeneity in atherosclerotic plaques in order to evaluate pro-atherogenic role of arsenic.

Domingo-Relloso et al.

Effect of various surface sterilisation treatments on medicinal plants Salvadora persica andSolanum surattense has been studied for in-vitro propagation. Surface sterilisation treatment was appliedby physical, chemical and physiochemical means. Chemical sterilisation was done with sodium hypochlorite,physically with sonication and physiochemically with combination of both. Sodium hypochlorite alonewas found to be effective for smooth textured plant i.e., Salvadora persica, whereas for rough texturedplant Solanum surattense a combination of both physiochemical means yielded good results. However,sonication alone did not render the effective way of surface sterilisation. Moreover, for Salvadora persica,10% sodium hypochlorite was effective in eliminating bacterial or fungal growth whereas in Solanumsurattense, a concentration of 15% sodium hypochlorite proved to be effective. In general, best resultswere achieved in the combined treatment by physiochemical means.