Antiobesity Effects of Extract from Spergularia marina Griseb in Adipocytes and High-Fat Diet-Induced Obese Rats

Obesity has recently risen and become a serious health concern in Korea according to the westernized diet and altered lifestyle. Hence, there is a growing interest in the supplementation of phytochemicals to find a safe and effective functional ingredient to treat obesity. Spergularia marina Griseb (SM) has traditionally been used as a natural herb against chronic diseases in Korea. In this study, we investigated the antiobesity effects of SM in vitro and in vivo. SM ethanol extract (SME) inhibited proliferation and differentiation in murine adipocytes and primary porcine pre-adipocytes in a dose-dependent manner. In the in vivo study, supplementation of SM powder (SMP) remarkably attenuated fat accumulation in HFD-induced obese rats. In addition, SMP supplementation improved lipid profiles in the serum and tissues of high-fat induced obese rats. Collectively, these data indicated that SME exhibited antiobesity effects by modulating adipogenesis and lipolysis. Furthermore, SMP could be developed as an obesity-induced metabolic syndrome treatment

Lowering <i>n</i>-6/<i>n</i>-3 Ratio as an Important Dietary Intervention to Prevent LPS-Inducible Dyslipidemia and Hepatic Abnormalities in <i>ob/ob</i> Mice

Obesity is closely associated with low-grade chronic and systemic inflammation and dyslipidemia, and the consumption of omega-3 polyunsaturated fatty acids (n-3 PUFAs) may modulate obesity-related disorders, such as inflammation and dyslipidemia. An emerging research question is to understand the dietary intervention strategy that is more important regarding n-3 PUFA consumption: (1) a lower ratio of n-6/n-3 PUFAs or (2) a higher amount of n-3 PUFAs consumption. To understand the desirable dietary intervention method of n-3 PUFAs consumption, we replaced lard from the experimental diets with either perilla oil (PO) or corn oil (CO) to have identical n-3 amounts in the experimental diets. PO had a lower n-6/n-3 ratio, whereas CO contained higher amounts of PUFAs; it inherently contained relatively lower n-3 but higher n-6 PUFAs than PO. After the 12-week dietary intervention in ob/ob mice, dyslipidemia was observed in the normal chow and CO-fed ob/ob mice; however, PO feeding increased the high density lipoprotein-cholesterol (HDL-C) level; further, not only did the HDL-C level increase, the low density lipoprotein-cholesterol (LDL-C) and triglyceride (TG) levels also decreased significantly after lipopolysaccharide (LPS) injection. Consequently, extra TG accumulated in the liver and white adipose tissue (WAT) of normal chow- or CO-fed ob/ob mice after LPS injection; however, PO consumption decreased serum TG accumulation in the liver and WAT. PUFAs replacement attenuated systemic inflammation induced by LPS injection by increasing anti-inflammatory cytokines but inhibiting pro-inflammatory cytokine production in the serum and WAT. PO further decreased hepatic inflammation and fibrosis in comparison with the ND and CO. Hepatic functional biomarkers (aspartate aminotransferase (AST) and alanine transaminase (ALT) levels) were also remarkably decreased in the PO group. In LPS-challenged ob/ob mice, PO and CO decreased adipocyte size and adipokine secretion, with a reduction in phosphorylation of MAPKs compared to the ND group. In addition, LPS-inducible endoplasmic reticulum (ER) and oxidative stress decreased with consumption of PUFAs. Taken together, PUFAs from PO and CO play a role in regulating obesity-related disorders. Moreover, PO, which possesses a lower ratio of n-6/n-3 PUFAs, remarkably alleviated metabolic dysfunction in LPS-induced ob/ob mice. Therefore, an interventional trial considering the ratio of n-6/n-3 PUFAs may be desirable for modulating metabolic complications, such as inflammatory responses and ER stress in the circulation, liver, and/or WAT

Nicotinamide Mononucleotide, an Intermediate of NAD⁺ Synthesis, Protects the Heart from Ischemia and Reperfusion

<div><p>Nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme for nicotinamide adenine dinucleotide (NAD⁺) synthesis, and Sirt1, an NAD⁺-dependent histone deacetylase, protect the heart against ischemia/reperfusion (I/R). It remains unknown whether Nampt mediates the protective effect of ischemic preconditioning (IPC), whether nicotinamide mononucleotide (NMN, 500 mg/kg), a product of Nampt in the NAD⁺ salvage pathway, mimics the effect of IPC, or whether caloric restriction (CR) upregulates Nampt and protects the heart through a Sirt1-dependent mechanism. IPC upregulated Nampt protein, and the protective effect of IPC against ischemia (30 minutes) and reperfusion (24 hours) was attenuated at both early and late phases in Nampt +/− mice, suggesting that Nampt plays an essential role in mediating the protective effect of IPC. In order to mimic the effect of Nampt, NMN was administered by intraperitoneal injection. NMN significantly increased the level of NAD⁺ in the heart at baseline and prevented a decrease in NAD⁺ during ischemia. NMN protected the heart from I/R injury when it was applied once 30 minutes before ischemia or 4 times just before and during reperfusion, suggesting that exogenous NMN protects the heart from I/R injury in both ischemic and reperfusion phases. The protective effect of NMN was accompanied by decreases in acetylation of FoxO1, but it was not obvious in Sirt1 KO mice, suggesting that the effect of NMN is mediated through activation of Sirt1. Compared to control diet (90% calories), CR (60% calories for 6 weeks) in mice led to a significant reduction in I/R injury, accompanied by upregulation of Nampt. The protective effect of CR against I/R injury was not significant in cardiac-specific Sirt1 KO mice, suggesting that the protective effect of CR is in part mediated through the Nampt-Sirt1 pathway. In conclusion, exogenous application of NMN and CR protects the heart by both mimicking IPC and activating Sirt1.</p></div

Yes-associated protein (YAP) mediates adaptive cardiac hypertrophy in response to pressure overload.

Cardiovascular disease (CVD) remains the leading cause of death globally, and heart failure is a major component of CVD-related morbidity and mortality. The development of cardiac hypertrophy in response to hemodynamic overload is initially considered to be beneficial; however, this adaptive response is limited and, in the presence of prolonged stress, will transition to heart failure. Yes-associated protein (YAP), the central downstream effector of the Hippo signaling pathway, regulates proliferation and survival in mammalian cells. Our previous work demonstrated that cardiac-specific loss of YAP leads to increased cardiomyocyte (CM) apoptosis and impaired CM hypertrophy during chronic myocardial infarction (MI) in the mouse heart. Because of its documented cardioprotective effects, we sought to determine the importance of YAP in response to acute pressure overload (PO). Our results indicate that endogenous YAP is activated in the heart during acute PO. YAP activation that depended upon RhoA was also observed in CMs subjected to cyclic stretch. To examine the function of endogenous YAP during acute PO, Yap+/flox;Creα-MHC (YAP-CHKO) and Yap+/flox mice were subjected to transverse aortic constriction (TAC). We found that YAP-CHKO mice had attenuated cardiac hypertrophy and significant increases in CM apoptosis and fibrosis that correlated with worsened cardiac function after 1 week of TAC. Loss of CM YAP also impaired activation of the cardioprotective kinase Akt, which may underlie the YAP-CHKO phenotype. Together, these data indicate a prohypertrophic, prosurvival function of endogenous YAP and suggest a critical role for CM YAP in the adaptive response to acute PO

NMN administration reduces I/R injury.

<p>Either NMN (500 mg/kg per injection) or vehicle (PBS) was administered (i.p. injection) to mice according to one of four different protocols (Figure S4 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098972#pone.0098972.s001" target="_blank">File S1</a>), the mice were subjected to I/R, and the extent of I/R injury was evaluated with TTC staining. In A-H, control mice were used. NMN or PBS was injected once 12 hours before I/R (A and B), once 30 minutes before I/R (C and D), once just before reperfusion (E and F) or once just before reperfusion and 3 more times every 6 hours thereafter (G and H). In I and J, NMN or PBS was injected once 30 minutes before I/R in Nampt+/− mice. Infarct area/AAR (A, C, E, G, and I) and AAR (B, D, F, H, and J) are shown. n = 4 to 7. n.s., not significant; * p<0.05, ** p<0.01.</p

Nampt expression is upregulated by ischemic preconditioning (IPC).

<p>A, The IPC protocol for wild-type mice. Mice on C57BL/6 background were subjected to 6 cycles of 3 minutes of ischemia plus 3 minutes of reperfusion. Sham groups were subjected to open chest surgery only. Arrows indicate the timing of biochemical analyses. B, Nampt mRNA expression 8 hours and 24 hours after IPC was determined by quantitative RT-PCR. n = 4. C, Nampt protein expression 20 minutes and 24 hours after IPC was determined by Western blot. D, Nampt protein expression with or without IPC in Nampt +/− mice and their wild-type littermates. E-G, Nampt +/− and littermate wild-type mice were subjected to IPC as shown in A. Five minutes or 24 hours after IPC, the mice were subjected to ischemia (30 minutes)/reperfusion (24 hours) (I/R). Some mice were subjected to I/R without IPC. Infarct size/AAR (E), AAR (F) and % reduction in infarct size compared to those without IPC (G) are shown. In E and F, ## p<0.01 vs. wild-type littermates subjected to the same surgery. n = 4 to 8. In G, ## p<0.01 vs. wild-type littermates subjected to I/R 5 minutes after IPC. In B, E, F and G, n.s., not significant; * p<0.05, ** p<0.01.</p

The cardioprotective effect of NMN depends on Sirt1 expression.

<p>A, Acetylation levels of FoxO1 after 30 minutes of ischemia or sham operation with or without NMN administration. n = 4. n.s., not significant; # p<0.05, ## p<0.01 vs. respective sham-operated group. B and C, Either NMN (500 mg/kg) or vehicle (PBS) was administered (i.p. injection) to control or cardiac-specific Sirt1 knockout (Sirt1KO) mice 30 minutes before subjecting the mice to 30 minutes of ischemia followed by 24 hours of reperfusion (I/R). The extent of infarction was evaluated with TTC staining. Infarct area/AAR (B) and AAR (C) are shown. n = 4 to 5. n.s., not significant; * p<0.05, ## p<0.01 vs. respective control mice group. D, Schematic model of the protective effect of NMN against I/R injury. IPC: ischemic preconditioning; CR: caloric restriction; NMN: nicotinamide mononucleotide; NAD: nicotinamide adenine dinucleotide; I/R: ischemia/reperfusion.</p

NAD⁺ content in the heart is reduced in Nampt +/− mice.

<p>A and B, Heart homogenates were prepared from Nampt +/− mice and their wild-type (Wt) littermates. A, NAD⁺ and NADH contents. B, NAD⁺/NADH ratio. C-E, Mice were subjected to sham procedure or IPC, as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098972#pone-0098972-g001" target="_blank">Figure 1A</a>. Mice were then subjected to either 30 minutes ischemia or sham operation 5 minutes after the sham procedure or either 5 minutes or 24 hours after IPC. C, NAD⁺ contents. D, NADH contents. E, NAD⁺/NADH ratio. In A-E, n = 4. n.s., not significant; * p<0.05, ** p<0.01.</p