Breast cancer (BC) has surpassed lung cancer as the most commonly diagnosed cancer among women in the US, as well as globally. A number of factors evidently contribute to the risk of developing BC, including age, physical activity, overweight/obesity, alcohol consumption, etc. It is of particular importance to study the role of body fatness and its potential influence on the risk of developing BC, as the number of individuals with obesity has increased with an alarming rate worldwide in recent decades. Epigenetics alterations are reversible, and do not alter the DNA sequence; however, they can affect gene expression via modifiable factors, including lifestyle and environmental factors. The present review article, in addition to providing overall reviews of obesity and BC in association with public health, concentrated on the epigenetic phenomena, with a focus on the well-studied DNA methylation, and its role in the association between obesity and BC. The present review aimed to provide insight into the understanding of the paradoxical effects of obesity on pre-vs. post-menopausal BC (pre-BC vs. post-BC), and describe the mechanisms through which folate metabolism/DNA methylation may be responsible for the protective effects of obesity on pre-BC. The literature presented in the present review article indicates that the epigenetic alterations represent a mediator in the association between obesity and BC; however, the mechanisms through which obesity differentially affects pre-vs. post-BC remain unclear. Further studies using animal models and the analyses of human tissue biopsies are thus required to delineate the paradoxical effects of obesity on BC. Contents1. Obesity and breast cancer 2. Epigenetic alterations in breast cancer 3. Obesity and DNA methylation 4. Obesity, DNA methylation and breast cancer 5. Folate metabolism in obesity and breast cancer 6. Conclusions and future perspectives Obesity and breast cancerPrevalence of breast cancer (BC). BC has surpassed lung cancer as the most commonly diagnosed type of cancer among women, with ~2.26 million new cases and ~685,000 deaths recorded globally in 2020. These numbers represent 24.5% of all new cancer cases and 15.5% of cancer-attributed mortality in women, respectively (1). In the US, the new cases of BC have also markedly increased, reaching top levels among all new cancer cases among women, with ~282,000 cases estimated in 2021 (30%); BC also represents the 2nd leading cause of cancer-related mortality, with 43,600 deaths (15%), coming only second following lung cancer (2).The BC incidence rates have consistently increased during the decades between 1970-2000 in a number of industrialized countries, likely reflecting changes in lifestyle associated with civilization and increased detection via mammographic screening. In the 2000s, the incidence rates had reached a

IntroductionExaiptasia diaphana is a popular model organism for exploring the symbiotic relationship observed between cnidarians and their microsymbionts. While physiological roles of algal photosymbionts (Symbiodinaceae) are well studied, the contributions of bacterial communities are less defined in this system.MethodsWe investigated microbial variation between distinct parts of the body and symbiotic state across four genets held in identical environmental conditions using 16s rRNA gene amplicon sequencing.ResultsWe found differentially abundant taxa between body part and symbiotic state that highlight the roles these bacteria may play in holobiont heterotrophy and nutrient cycling. Beta-diversity analysis revealed distinct communities between symbiotic states consistent with previous studies; however, we did not observe the presence of previously reported core microbiota. We also found community differences across clonal lines, despite years of identical rearing conditions. ConclusionThese findings suggest the Exaiptasia bacterial microbiome is greatly influenced by host genetics and unpredictable environmental influences.

Enteroviral infections are implicated in islet autoimmunity and type 1 diabetes (T1D) pathogenesis. Significant β-cell stress and damage occur with viral infection, leading to cells that are dysfunctional and vulnerable to destruction. Human stem cell-derived β (SC-β) cells are insulin-producing cell clusters that closely resemble native β cells. To better understand the events precipitated by enteroviral infection of β cells, we investigated transcriptional and proteomic changes in SC-β cells challenged with coxsackie B virus (CVB). We confirmed infection by demonstrating that viral protein colocalized with insulin-positive SC-β cells by immunostaining. Transcriptome analysis showed a decrease in insulin gene expression following infection, and combined transcriptional and proteomic analysis revealed activation of innate immune pathways, including type I interferon (IFN), IFN-stimulated genes, nuclear factor-kappa B (NF-κB) and downstream inflammatory cytokines, and major histocompatibility complex (MHC) class I. Finally, insulin release by CVB4-infected SC-β cells was impaired. These transcriptional, proteomic, and functional findings are in agreement with responses in primary human islets infected with CVB ex vivo. Human SC-β cells may serve as a surrogate for primary human islets in virus-induced diabetes models. Because human SC-β cells are more genetically tractable and accessible than primary islets, they may provide a preferred platform for investigating T1D pathogenesis and developing new treatments.

Type 1 diabetes is a chronic autoimmune disease, characterized by the immune-mediated destruction of insulin-producing b cells of pancreatic islets. Essential components of the innate immune antiviral response, including type I IFN and IFN receptor (IFNAR)-mediated signaling pathways, likely contribute to human type 1 diabetes susceptibility. We previously showed that LEW.1WR1 Ifnar1 À/À rats have a significant reduction in diabetes frequency following Kilham rat virus (KRV) infection. To delineate the impact of IFNAR loss on immune cell populations in KRV-induced diabetes, we performed flow cytometric analysis in spleens from LEW.1WR1 wild-type (WT) and Ifnar1 À/À rats after viral infection but before the onset of insulitis and diabetes. We found a relative decrease in CD8 + T cells and NK cells in KRV-infected LEW.1WR1 Ifnar1 À/À rats compared with KRV-infected WT rats; splenic regulatory T cells were diminished in WT but not Ifnar1 À/À rats. In contrast, splenic neutrophils were increased in KRV-infected Ifnar1 À/À rats compared with KRV-infected WT rats. Transcriptional analysis of splenic cells from KRV-infected rats confirmed a reduction in IFN-stimulated genes in Ifnar1 À/À compared with WT rats and revealed an increase in transcripts related to neutrophil chemotaxis and MHC class II. Single-cell RNA sequencing confirmed that MHC class II transcripts are increased in monocytes and macrophages and that numerous types of splenic cells harbor KRV. Collectively, these findings identify dynamic shifts in innate and adaptive immune cells following IFNAR disruption in a rat model of autoimmune diabetes, providing insights toward the role of type I IFNs in autoimmunity.

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