Exploration of the Effect on Genome-Wide DNA Methylation by miR-143 Knock-Out in Mice Liver

Genes and pathways associated with fear discrimination identified by genome-wide DNA methylation and RNA-seq analyses in nucleus accumbens in mice

Fear memory is critical for individual survival. However, the maladaptive fear response is one of the hallmarks of fear-related disorders, which is characterized by the failure to discriminate threatening signals from neutral or safe cues. The biological mechanisms of fear discrimination remain to be clarified. In this study, we found that the nucleus accumbens (NAc) was indispensable for the formation of cued fear memory in mice, during which the expression of DNA methyltransferase 3a gene (DNMT3a) increased. Injection of Zebularine, a nonspecific DNMT inhibitor, into NAc immediately after conditioning induced a maladaptive fear response to neutral cue (CS^-). Using whole-genome bisulfite sequencing (WGBS), differentially methylated sites and methylated regions (DMRs) were investigated. 16,226 DMRs in the genenome were identified, in which, 214 genes with significant differences in their methylation levels and mRNA expression profiles were identified through correlation analysis. Notably, 15 genes were synaptic function-related and 8 genes were enriched in the cGMP-PKG signaling pathway. Moreover, inhibition of PKG impaired fear discrimination. Together, our results revealed the profile and role of genome-wide DNA methylation in NAc in the regulation of fear discrimination.

Upregulation of Actin-Related Protein 2 (ACTR2) Exacerbated the Malignancy of Diffuse Large B-Cell Lymphoma through Activating Wnt Signaling

This investigation mainly explores the roles of actin-related protein 2 (ACTR2) in diffuse large B-cell lymphoma (DLBCL). We first assessed the level of ACTR2 and its association with the overall survival (OS) of DLBCL. The results indicated that ACTR2 was upregulated in DLBCL and was associated with unfavorable prognosis of DLBCL. Next, the effect of ACTR2 knockdown or overexpression on DLBCL was evaluated in vitro. Our investigation revealed that ACTR2 depletion inhibited the malignant behaviors of DLBCL cells; whereas, ACTR2 abundance promoted those behaviors. Besides, ACTR2 activated the Wnt signaling in DLBCL and exerted its oncogenic influence on DLBCL through Wnt signaling in vitro and in vivo. To summarize, our study implicated that ACTR2 was a promising therapeutic target for DLBCL, which might become a novel direction to improve our understanding on DLBCL.

LPS-Induced Inhibition of miR-143 Expression in Brown Adipocytes Promotes Thermogenesis and Fever

Fever is an important part of inflammatory response to infection. Although brown adipose tissue (BAT) thermogenesis is known to be potently influenced by systemic inflammation, the role of BAT during infection-induced fever remains largely unknown. Here, we injected mice with a low dose of LPS and found that low-dose LPS can directly induce thermogenesis of brown adipocytes. It is known that miR-143 is highly expressed in the BAT, and miR-143 knockout mice exhibited stronger thermogenesis under cold exposure. Interestingly, miR-143 was negatively correlated with an LPS-induced increase of TNFα and IL-6 mRNA levels, and the IL-6 pathway may mediate the inhibition of miR-143 expression. Moreover, miR-143 is down-regulated by LPS, and overexpression of miR-143 in brown adipocytes by lentivirus could rescue the enhancement of UCP1 protein expression caused by LPS, hinting miR-143 may be an important regulator of the thermogenesis in brown adipocytes. More importantly, the knockout of miR-143 further enhanced the LPS-induced increase of body temperature and BAT thermogenesis, and this result was further confirmed by in vitro experiments by using primary brown adipocytes. Mechanistically, adenylate cyclase 9 (AC9) is a new target gene of miR-143 and LPS increases BAT thermogenesis by a way of inhibiting miR-143 expression, a negative regulator for AC9. Our study considerably improves our collective understanding of the important function of miR-143 in inflammatory BAT thermogenesis.

miR-143-null Is against Diet-Induced Obesity by Promoting BAT Thermogenesis and Inhibiting WAT Adipogenesis

Excessive energy intake is the main cause of obesity, and stimulation of brown adipose tissue (BAT) thermogenesis has emerged as an attractive tool for anti-obesity. Although miR-143 has been reported to promote white adipocyte differentiation, its role in BAT remains unclear. In our study, we found that during HFD-induced obesity, the expression of miR-143 in BAT was significantly reduced, and the expression of miR-143 in WAT first increased and then decreased. Knockout (KO) of miR-143 with CRISPR/Cas9 did not affect the energy metabolism of normal diet fed mice and brown adipocyte differentiation but inhibited the differentiation of white adipocytes. Importantly, during high fat diet-induced obesity, miR-143KO significantly reduced body weight, and improved energy expenditure, insulin sensitivity, and glucose tolerance. Further exploration showed that miR-143KO reduced the weight of adipose tissue, promoted mitochondrial number and functions, induced thermogenesis and lipolysis of BAT, increased lipolysis, and inhibited lipogenesis of white adipose tissue (WAT). Our study considerably improves our collective understanding of the function of miR-143 in adipose tissue and its potential significance in anti-obesity and provides a new avenue for the management of obesity through the inhibition of miR-143 in BAT and WAT.

miR-146a-5p promotes epithelium regeneration against LPS-induced inflammatory injury via targeting TAB1/TAK1/NF-κB signaling pathway

Intestinal inflammation often restricts the health and production of animals. MiR-146a has been proved to be an anti-inflammatory molecule in inflammatory disorders, but its role in the intestinal injury and regeneration remains unclear. The study aimed to explore the inflammatory response of intestinal epithelial cells (IECs) in intestinal tissue-specific miR-146a-5p knockout mouse models. We identified the role of miR-146a-5p in inhibiting inflammatory response and promoting proliferation under lipopolysaccharide (LPS) stimulation in vitro and vivo. LPS stimulation significantly increased the expression of TNF-α, IL6 and inhibited IPEC-J2 cell proliferation. Overexpression of miR-146a-5p can reverse the effect of LPS stimulation, and promote the proliferation of intestinal epithelial cells. In the LPS challenge experiment in intestine-specific miR-146a knock-out mice (CKO) and Floxp^+/+ mice (CON), CKO mice were more sensitive to LPS stimulation, with more weight loss and more severe intestinal morphological damage than CON mice. Also, miR-146a-5p regulated LPS-induced intestinal injury, inflammation by targeting TAB1. Taken together, miR-146a may function as an anti-inflammatory factor in IECs by targeting TAB1/TAK1-IKK-NF-κB signaling pathway. miR-146a-5p may represent a promising biomarker for inflammatory disorders, and may provide an effective therapeutic method to alleviate weaning stress in piglets and some experimental basis to improve the intestinal health of livestock.