Palmitate induces insulin resistance and a pro-atherogenic phenotype in monocytes

The present study investigated the effect of the two most abundant FFA in plasma – palmitate and oleate – on insulin sensitivity and vascular function (monocyte phenotype and adhesion to endothelium) using in vitro cell culture models and Wistar rats. Palmitate at 300µM for 6h induced insulin resistance in THP-1 monocytes and L6 monocytes. The ceramide synthesis pathway partly accounted for the palmitate-induced insulin resistance in THP-1 monocytes but not for L6 myotubes. Oleate treatment did not induce insulin resistance in either cell type and co-incubation with oleate protected cells from palmitate-induced insulin resistance. Palmitate at 300µN for 24h significantly increased cell surface CD11b and CD36 expression in U937 monocytes. The increase in CD11b and CD36 expression was effectively inhibited by Fumonisin B1, an inhibitor of ceramide synthesis. Oleate treatment did not show any effect on CD11b and CD36 expression and co-incubation with oleate antagonised the effect of palmitate on CD11b and CD36 expression in U937 monocytes. The increase in CD11b expression did not affect U937 monocyte adhesion to ICAM-1. Treating Wistar rats with palmitate for 6h caused a transient delay in glucose disposal and an increase in adhesion of U937 monocytes to the aortic endothelium, particularly at bifurcations. In conclusion, the present study demonstrates that the saturated free fatty acid palmitate induces insulin resistance and a pro-atherogenic phenotype for monocytes, whereas the unsaturated free fatty acid oleate does not. In vivo studies also confirmed that palmitate induces insulin resistance and an increase in monocyte adhesion to aorta

Palmitate induces insulin resistance and a pro-atherogenic phenotype in monocytes

The present study investigated the effect of the two most abundant FFA in plasma – palmitate and oleate – on insulin sensitivity and vascular function (monocyte phenotype and adhesion to endothelium) using in vitro cell culture models and Wistar rats. Palmitate at 300µM for 6h induced insulin resistance in THP-1 monocytes and L6 monocytes. The ceramide synthesis pathway partly accounted for the palmitate-induced insulin resistance in THP-1 monocytes but not for L6 myotubes. Oleate treatment did not induce insulin resistance in either cell type and co-incubation with oleate protected cells from palmitate-induced insulin resistance. Palmitate at 300µN for 24h significantly increased cell surface CD11b and CD36 expression in U937 monocytes. The increase in CD11b and CD36 expression was effectively inhibited by Fumonisin B1, an inhibitor of ceramide synthesis. Oleate treatment did not show any effect on CD11b and CD36 expression and co-incubation with oleate antagonised the effect of palmitate on CD11b and CD36 expression in U937 monocytes. The increase in CD11b expression did not affect U937 monocyte adhesion to ICAM-1. Treating Wistar rats with palmitate for 6h caused a transient delay in glucose disposal and an increase in adhesion of U937 monocytes to the aortic endothelium, particularly at bifurcations. In conclusion, the present study demonstrates that the saturated free fatty acid palmitate induces insulin resistance and a pro-atherogenic phenotype for monocytes, whereas the unsaturated free fatty acid oleate does not. In vivo studies also confirmed that palmitate induces insulin resistance and an increase in monocyte adhesion to aorta

Berberine regulates endocrine function in mice with polycystic ovary syndrome through PI3K/Akt/GSK-3β insulin signaling pathway

Purpose: To study the influence of berberine on endocrine status in mice with polycystic ovary syndrome (PCOS), and the underlying mechanism of action. Methods: A total of 80 mice were used in this research. Sixteen mice were randomly selected to serve as control. The remaining 64 mice were subcutaneously given dehydroepiandrosterone (DHEA) injection to establish a mouse model of PCOS. The PCOS mice were randomly divided into model group, and low-dose-, medium-dose and high-dose berberine groups. Oral glucose tolerance test (OGTT) and expression levels of PI3K/Akt/GSK-3 signaling pathway related proteins (PI3K 85, Akt2, p-GSK-3 Tyr216, p-GSK-3β Ser9, and GSK-3) were evaluated. Results: At 60 and 120 min, OGTT blood glucose level of model group was significantly higher than that of blank control group, but it was significantly lower in the berberine dose groups than in model group (p < 0.05). There were significantly higher protein expression levels of pi3k85, AKT2 and p-GSK-3β tyr116 in berberine dose groups than in model mice, but the protein levels of p-GSK-3β ser9 in berberine dose groups were significantly lower than that in model mice. Conclusion: Berberine improved endocrine function in PCOS mice through a mechanism involving regulation of the key proteins of PI3K/Akt/GSK-3 β insulin signaling pathway. Thus, berberine may potentially play a similar role in humans with PCOS functions. However, clinical trials need to be carried out first

Chinese Celebrities’ Political Signaling on Weibo

In China, celebrities can dominate public discourse and shape popular culture, but they are under the state’s close gaze. Recent studies have revealed how the state disciplines and co-opts celebrities to promote patriotism, foster traditional values, and spread political propaganda. However, how do celebrities adapt to the changing political environment? Focusing on political signaling on Weibo, we analyze a novel dataset and find that the vast majority of top celebrities repost from official accounts of government agencies and state media outlets, though there are variations. Younger celebrities with more followers tend to repost from official accounts more. Celebrities from Taiwan tend to repost less than those from the mainland and Hong Kong, despite being subject to the same rules. However, the frequent political signaling by the most influential celebrities among younger generations suggests that the state has co-opted celebrity influence on social media to broadly promote its political objectives

The Transgressive Rhetoric of Standup Comedy in China

Public discourse under authoritarian rule is not monolithic. Yet how popular rhetoric engages with the hegemonic rhetoric in the same discursive space remains understudied. This article examines the rhetoric of a standup comedy show in China, streamed online and widely popular among Chinese millennials, to understand how alternative views on social issues can coexist with the hegemonic rhetoric. Using critical discourse analysis, it argues that some standup comedy performances transgress the hegemonic rhetoric of positive energy without outright subversion. Comedians use subversive affirmation, self-deprecation, ambiguity, absurd fantasy, and irony to present alternative viewpoints on social issues of broad interest, such as the neoliberal work culture and gender norms. The subtle yet powerful transgressions introduce previously marginal views into the public discourse, diminishing the aura of wide acceptance and authority assumed by the hegemonic rhetoric. The standup comedy performances thus open up new discursive pathways towards non-state-sanctioned views on important social issues