Expression profile of hepatic genes related to lipid homeostasis in LSR heterozygous mice contributes to their increased response to high-fat diet

Garcinia cambogia Extract Increased Hepatic Levels of Lipolysis-Stimulated Lipoprotein Receptor and Lipids in Mice on Normal Diet

Garcinia cambogia extract (GCE) is a popular weight-loss supplement that also lowers plasma triglyceride (TG) levels. We hypothesized that GCE-mediated inhibition of ATP citrate lyase and thereby hepatic TG production could lead to compensatory mechanisms, including increased hepatic TG uptake via lipoprotein receptors. GCE (20 mg/day) administered 40 days orally to female C57BL/6Rj mice on a standard chow diet led to a decrease in both plasma fasting and post-prandial TG-rich lipoprotein levels, but with no significant change in body weight gain. Lipolysis stimulated lipoprotein receptor (LSR) protein levels, but not those of LDL-receptor, were increased as compared to controls. Mouse Hepa1-6 cells treated with the GCE active ingredient, hydroxycitrate, also led to increased LSR protein levels. Hepatic total cholesterol, TG, and muscle TG contents were higher in GCE-treated animals as compared to controls, whereas adipose TG levels were unchanged. LSR and LDL-receptor protein levels were correlated with liver total cholesterol, but only LDL-receptor was associated with liver TG. These results show that GCE treatment in mice on a standard chow diet led to significantly increased liver and muscle lipids, with no significant change in adipose tissue TG levels, which should be considered in the long-term use of GCE.

Hepatic Lipid Metabolism Disorder and Atherosclerosis

Lipid metabolism disorder plays a fundamental role in the pathogenesis of atherosclerosis. As the largest metabolic organ of the human body, liver has a key role in lipid metabolism by influencing fat production, fat decomposition, and the intake and secretion of serum lipoproteins. Numerous clinical and experimental studies have indicated that the dysfunction of hepatic lipid metabolism is closely tied to the onset of atherosclerosis. However, the identity and functional role of hepatic lipid metabolism responsible for these associations remain unknown. This review presented that cholesterol synthesis, cholesterol transport, and the metabolism of triglyceride, lipoproteins, and fatty acids are all associated with hepatic lipid metabolism and atherosclerosis. Moreover, we also discussed the roles of gut microbiota, inflammatory response, and oxidative stress in the pathological association between hepatic lipid metabolism and atherosclerosis. These significant evidences support strongly that hepatic lipid metabolism disorders may increase the risk of atherosclerosis.

Leptin Downregulates Angulin-1 in Active Crohn's Disease via STAT3

Crohn’s disease (CD) has an altered intestinal barrier function, yet the underlying mechanisms remain to be disclosed. The tricellular tight junction protein tricellulin is involved in the maintenance of the paracellular macromolecule barrier and features an unchanged expression level in CD but a shifted localization. As angulins are known to regulate the localization of tricellulin, we hypothesized the involvement of angulins in CD. Using human biopsies, we found angulin-1 was downregulated in active CD compared with both controls and CD in remission. In T84 and Caco-2 monolayers, leptin, a cytokine secreted by fat tissue and affected in CD, decreased angulin-1 expression. This effect was completely blocked by STAT3 inhibitors, Stattic and WP1066, but only partially by JAK2 inhibitor AG490. The effect of leptin was also seen at a functional level as we observed in Caco-2 cells an increased permeability for FITC-dextran 4 kDa indicating an impaired barrier against macromolecule uptake. In conclusion, we were able to show that in active CD angulin-1 expression is downregulated, which leads to increased macromolecule permeability and is inducible by leptin via STAT3. This suggests that angulin-1 and leptin secretion are potential targets for intervention in CD to restore the impaired intestinal barrier.

Anti-aging properties of Dendrobium nobile Lindl.: From molecular mechanisms to potential treatments

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium Nobile Lindl. (DNL) is one of the central herbs in traditional Chinese medicine which mainly distributes in Guizhou, Yunnan, Guangxi and other sub-tropical areas south of the Yangtze River. In the past decades, it has been used to treat tumors, hyperglycemia, hyperlipidemia, and diseases of the nervous system that may be caused by aging.

AIM OF THE REVIEW

The purpose of this review is to summarize the anti-aging information of DNL from the molecular mechanism level, including classic theories related to aging, main chemical components, pharmacological research and anti-aging theory based on traditional Chinese medicine theory, for exploring the future development and clinical treatment.

MATERIALS AND METHODS

The information in this paper has been collected from the scientific literature databases including PubMed, Google Scholar, Web of Science, Science Direct, Springer, China National Knowledge Infrastructure, published books, Ph.D. and M.S. dissertations systematically.

RESULTS

In this paper, we have reviewed the several mechanisms underlying the potential effects of DNL on the prevention of aging, including the scavenging of free radicals for oxidation, delaying of DNA impairment, inhibition of apoptosis, and alteration of DNA methylation. Together with the theory of telomeres, this review also has summarized recent research progress in the use of DNL and its traditional efficacy.

CONCLUSIONS

We conclude that "strengthening Yin and benefiting the spirit", "thickening the intestine and stomach", "lightning the body and prolonging the life-span", and delaying aging, are key effects of DNL that can be used to combat age-related diseases (ARDs) such as Alzheimer's disease, hyperlipidemia, and diabetes. This review provides a reference for future study of ARDs and the clinical application of DNL.

Relationship between apical junction proteins, gene expression and cancer

The apical junctional complex (AJC) is a cell-cell adhesion system present at the upper portion of the lateral membrane of epithelial cells integrated by the tight junction (TJ) and the adherens junction (AJ). This complex is crucial to initiate and stabilize cell-cell adhesion, to regulate the paracellular transit of ions and molecules and to maintain cell polarity. Moreover, we now consider the AJC as a hub of signal transduction that regulates cell-cell adhesion, gene transcription and cell proliferation and differentiation. The molecular components of the AJC are multiple and diverse and depending on the cellular context some of the proteins in this complex act as tumor suppressors or as promoters of cell transformation, migration and metastasis outgrowth. Here, we describe these new roles played by TJ and AJ proteins and their potential use in cancer diagnostics and as targets for therapeutic intervention.

Alkaloids of dendrobium nobile lindl. Altered hepatic lipid homeostasis via regulation of bile acids

ETHNOPHARMACOLOGICAL RELEVANCE

Accumulation of hepatic lipid promotes systemic metabolic dysfunction and results in fatty liver. Our previous studies have shown that the alkaloids of Dendrobium nobile Lindl. (DNLA) could regulate the lipid metabolism gene expression in livers of mice. However, the protective effects on hepatic lipid homeostasis and the underlying mechanisms are still unclear.

MATERIALS AND METHODS

The C57BL/6 male mice were randomly divided into four groups, including control group, model group, DNLA treatment group, and simvastatin positive control group. Mice in the control group and the other three groups were fed with control diet and high fat diet during the full course of this study, respectively. Hepatic lipid accumulation was induced by HFD in mice after 18 weeks of feeding. DNLA (15 mg/kg) and simvastatin (20 mg/kg) were administrated intragastrically in the DNLA treatment group and simvastatin positive control group for another 18 weeks, respectively. HE staining and Oil-Red-O staining of liver tissues were observed. TC and TG levels in liver were assayed. The amount of major bile acids in mice livers were quantified by UPLC-MS. Expression levels of genes were tested by the real-time PCR.

RESULTS

The results of HE staining and Oil-Red-O staining showed that DNLA could improve hepatic lipid homeostasis. DNLA significantly decreased liver TC and TG levels in the DNLA group. Moreover, the UPLC-MS analysis showed that DNLA did not only influence the hepatic bile acid quantity but did raise the hydrophilicity. Compared with the model group, DNLA decreased the hepatic levels of several free bile acids, including LCA, DCA, CA, and CDCA, and increased most important taurine-conjugated bile acids levels in liver, including TMCAs, TCDCA, TUDCA, and THDCA. In addition, DNLA also decreased the CA/CDCA ratio. The gene expression levels of Cyp27a1, Cyp3a11, Fxr, and Shp were up-regulated in DNLA treatment group.

CONCLUSION

DNLA may improve the hepatic abnormal lipid profile of HFD-fed mice via two pathways: (1) enhancing the taurine-conjugated bile acids which are highly hydrophilic and contribute to the excretion of cholesterol; (2) decreasing the CA/CDCA ratio which is positively related to cholesterol absorption.

The bicellular tensile force sorts the localization of LSRs in bicellular and tricellular junctions

Lipolysis-stimulated lipoprotein receptors (LSRs) localize to tricellular tight junctions. Recent studies have shown that changes in the localization and expression profiles of LSRs are associated with malignancy of endometrial carcinomas, although the precise mechanisms by which malignant progression induces changes in the localization of LSRs are still unknown. In this study, we found that changes in cell tension correlated with alterations in the junctional localization of LSRs in endometrial cancer Sawano cells. At high cell densities, myosin phosphatase target subunit 1 (MYPT1) localized to bicellular junctions, whereas activated myosin regulatory light chain 2 (MRLC2) was dislocated from these regions, suggesting that circumferential tensile forces decreased at high cell densities. Under these conditions, LSRs localized to tricellular junctions. In contrast, a phosphorylated form of MRLC2 localized to bicellular regions, while MYPT1 was excluded from these regions, suggesting that tensile forces formed along the circumferential edge at low cell densities. It is noteworthy that, when cells were cultured under these conditions, LSRs localized to bicellular regions. Upon treatment with a myosin inhibitor, LSR localization in bicellular junctions decreased at low cell densities. Overall, our results indicate that the modulation of cellular tension was involved in the translocation of LSRs from bicellular to tricellular tight junctions.