The cholecystokinin receptor agonist, CCK-8, induces adiponectin production in rat white adipose tissue

Naringenin Induces HepG2 Cell Apoptosis via ROS-Mediated JAK-2/STAT-3 Signaling Pathways

Hepatocarcinoma is one of the most prevalent digestive system tumors worldwide and lacks effective therapy. Recently, naringenin has been isolated from some citrus fruits, and its anticancer effects have been tested. However, the molecular mechanisms of naringenin and the potential implications of oxidative stress in naringenin-induced cytotoxicity in HepG2 cells remain elusive. Based on the above, the present study examined the effect of naringenin on the cytotoxic and anticancer mechanisms of HepG2 cells. Naringenin-induced HepG2 cell apoptosis was confirmed via the accumulation of the sub-G1 cell population, phosphatidylserine exposure, mitochondrial transmembrane potential loss, DNA fragmentation, caspase-3 activation, and caspase-9 activation. Furthermore, naringenin enhanced cytotoxic effects on HepG2 cells and triggered intracellular reactive oxygen species; the signaling pathways of JAK-2/STAT-3 were inhibited, and caspase-3 was activated to advance cell apoptosis. These results suggest that naringenin plays an important role in inducing apoptosis in HepG2 cells and that naringenin may be a promising candidate for cancer therapy.

Krüppel-Like Factor 2 Is a Gastric Cancer Suppressor and Prognostic Biomarker

Gastric cancer (GC) is a common digestive tract tumor. Due to its complex pathogenesis, current diagnostic and therapeutic effects remain unsatisfactory. Studies have shown that KLF2, as a tumor suppressor, is downregulated in many human cancers, but its relationship and role with GC remain unclear. In the present study, KLF2 mRNA levels were significantly lower in GC compared to adjacent normal tissues, as analyzed by bioinformatics and RT-qPCR, and correlated with gene mutations. Tissue microarrays combined with immunohistochemical techniques showed downregulation of KLF2 protein expression in GC tissue, which was negatively correlated with patient age, T stage, and overall survival. Further functional experiments showed that knockdown of KLF2 significantly promoted the growth, proliferation, migration, and invasion of HGC-27 and AGS GC cells. In conclusion, low KLF2 expression in GC is associated with poor patient prognosis and contributes to the malignant biological behavior of GC cells. Therefore, KLF2 may serve as a prognostic biomarker and therapeutic target in GC.

Ginkgolide A Participates in LPS-Induced PMVEC Injury by Regulating miR-224 and Inhibiting p21 in a Targeted Manner

Most studies have focused on the protective effects of ginkgolide A against ischemia/reperfusion-induced cardiomyopathy and injury of the brain, liver, and other organs, but there are few reports about the protection of lung tissues. This study was designed to clarify the protection of ginkgolide A against lipopolysaccharide (LPS)-induced pulmonary microvascular endothelial cell (PMVEC) injury. PMVECs were extracted and fell into control, LPS, and ginkgolide A groups. Next, we delved into the growth activity and apoptosis rate of cells via the CCK-8 assay and Hoechst staining, independently. Beyond that, western blotting (WB) was implemented for measurement of the expressions of cyclin D1, cyclin-dependent kinase 4 (CDK4), and CDK inhibitor (p21) that pertained to the cell cycle. The target sites of ginkgolide A were confirmed by miRNA array and real-time quantitative PCR. The relationship between miR-224 and p21 was analyzed using dual-luciferase reporter gene assay. Compared with the control group, the LPS group and ginkgolide A group had significantly decreased cell growth activity and relative expressions of cyclin D1 and CDK4 and elevated apoptosis rate and p21 expression. Pronounced elevations were observable in the cell growth activity and expressions of cyclin D1, CDK4, and p21, while the ginkgolide A group presented with a reduced apoptosis rate in comparison with the LPS group (P < 0.05). MiR-224 was the target of ginkgolide A, which had targeted regulatory effects on p21. Ginkgolide A can modulate miR-224 expression and regulate p21 expression in a targeted manner to enhance the resistance of PMVECs to LPS-induced cell apoptosis.

Laser Additive Manufacturing of Anti-Tetrachiral Endovascular Stents with Negative Poisson’s Ratio and Favorable Cytocompatibility

Laser additive manufacturing (LAM) of complex-shaped metallic components offers great potential for fabricating customized endovascular stents. In this study, anti-tetrachiral auxetic stents with negative Poisson ratios (NPR) were designed and fabricated via LAM. Poisson’s ratios of models with different diameters of circular node (DCN) were calculated using finite element analysis (FEA). The experimental method was conducted with the LAM-fabricated anti-tetrachiral stents to validate their NPR effect and the simulation results. The results show that, with the increase in DCN from 0.6 to 1.5 mm, the Poisson ratios of anti-tetrachiral stents varied from −1.03 to −1.12, which is in line with the simulation results. The interrelationship between structural parameters of anti-tetrachiral stents, their mechanical properties and biocompatibility was demonstrated. The anti-tetrachiral stents with a DCN of 0.9 mm showed the highest absolute value of negative Poisson’s ratio, combined with good cytocompatibility. The cytocompatibility tests indicate the envisaged cell viability and adhesion of the vascular endothelial cell on the LAM-fabricated anti-tetrachiral auxetic stents. The manufactured stents exhibit great superiority in the application of endovascular stent implantation due to their high flexibility for easy maneuverability during deployment and enough strength for arterial support.

Cholecystokinin promotes functional expression of the aquaglycerol channel aquaporin 7 in adipocytes

BACKGROUND AND PURPOSE

Cholecystokinin (CCK) promotes triglyceride storage and adiponectin production in white adipose tissue (WAT), suggesting that CCK modulates WAT homeostasis. Our goal was to investigate the role of CCK in regulating the expression and function of the aquaglycerol channel aquaporin 7 (AQP7), a protein that is pivotal for maintaining adipocyte homeostasis and preserving insulin responsiveness.

EXPERIMENTAL APPROACH

The effect of the bioactive fragment of CCK, CCK-8, in regulating adipose AQP7 expression and glycerol efflux was assessed in rats as well as in pre-adipocytes. Moreover, the involvement of insulin receptors in the effects of CCK-8 was characterized in pre-adipocytes lacking insulin receptors.

KEY RESULTS

CCK-8 induced AQP7 gene expression in rat WAT, concomitantly increasing plasma glycerol concentration. In isolated pre-adipocytes, CCK-8 also enhanced both AQP7 expression and glycerol leakage. The effect of CCK-8 was independent of the lipolysis rate, as CCK-8 failed to promote fatty acid release by adipocytes. In addition, CCK-8 did not enhance hormone sensitive lipase phosphorylation, which is the rate-limiting step of lipolysis. Moreover, the effects of CCK-8 were dependent on the activation of protein kinase B and PPARγ. Silencing insulin receptor (IR) expression inhibited CCK-8-induced Aqp7 expression in pre-adipocytes. Furthermore, insulin enhanceded the effect of CCK-8.

CONCLUSIONS AND IMPLICATIONS

CCK regulates AQP7 expression and function, and this effect is dependent on insulin. Accordingly, CCK receptor agonists could be suitable for preserving and improving insulin responsiveness in WAT.

Free fatty acid receptors in the endocrine regulation of glucose metabolism: Insight from gastrointestinal-pancreatic-adipose interactions

Glucose metabolism is primarily controlled by pancreatic hormones, with the coordinated assistance of the hormones from gastrointestine and adipose tissue. Studies have unfolded a sophisticated hormonal gastrointestinal-pancreatic-adipose interaction network, which essentially maintains glucose homeostasis in response to the changes in substrates and nutrients. Free fatty acids (FFAs) are the important substrates that are involved in glucose metabolism. FFAs are able to activate the G-protein coupled membrane receptors including GPR40, GPR120, GPR41 and GPR43, which are specifically expressed in pancreatic islet cells, enteroendocrine cells as well as adipocytes. The activation of FFA receptors regulates the secretion of hormones from pancreas, gastrointestine and adipose tissue to influence glucose metabolism. This review presents the effects of the FFA receptors on glucose metabolism via the hormonal gastrointestinal-pancreatic-adipose interactions and the underlying intracellular mechanisms. Furthermore, the development of therapeutic drugs targeting FFA receptors for the treatment of abnormal glucose metabolism such as type 2 diabetes mellitus is summarized.

Ferroptosis-Inhibitory Effect and Possible Mechanisms of Ellagitannin Geraniin

The search for safe and effective ferroptosis-inhibitors has become an important topic. Geraniin, an ellagitannin bearing hexahydroxydiphenoyl (HHDP) and dehydrohexahydroxydiphenoyl (DHHDP) groups, was observed to inhibit erastin-induced ferroptosis in bone marrow-derived mesenchymal stem cells (bmMSCs). To determine the mechanism, geraniin was further analyzed using UV-vis spectra and several colorimetric assays, where its IC50 values were always much lower than that of the Trolox positive control. When interacted with several free radicals, geraniin gave no radical adduct formation (RAF) peak in the ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry. In conclusion, geraniin exhibits ferroptosis-inhibitory potential towards erastin-treated bmMSCs; such potential may mainly stem from its strong lipid peroxidation (LPO)-inhibition, Fe2+ -chelating, and antioxidant actions. Geraniin gives neither dimer nor radical adduct, owing to the bulky HHDP (or DHHDP) group; thus, it is considered as a safe and effective ferroptosis-inhibitor.

Gut-adipose tissue crosstalk: A bridge to novel therapeutic targets in metabolic syndrome?

The gut is one of the main endocrine organs in our body, producing hormones acknowledged to play determinant roles in controlling appetite, energy balance and glucose homeostasis. One of the targets of such hormones is the adipose tissue, a major energetic reservoir, which governs overall metabolism through the secretion of adipokines. Disturbances either in nutrient and metabolic sensing and consequent miscommunication between these organs constitute a key driver to the metabolic complications clustered in metabolic syndrome. Thus, it is essential to understand how the disruption of this crosstalk might trigger adipose tissue dysfunction, a strong characteristic of obesity and insulin resistance. The beneficial effects of metabolic surgery in the amelioration of glucose homeostasis and body weight reduction allowed to understand the potential of gut signals modulation as a treatment for metabolic syndrome-related obesity and type 2 diabetes. In this review, we cover the effects of gut hormones in the modulation of adipose tissue metabolic and endocrine functions, as well as their impact in tissue plasticity. Furthermore, we discuss how the modulation of gut secretome, either through surgical procedures or pharmacological approaches, might improve adipose tissue function in obesity and metabolic syndrome.

The cholecystokinin receptor agonist, CCK-8, induces adiponectin production in rat white adipose tissue

BACKGROUND AND PURPOSE

A cholecystokinin (CCK) system has been identified in white adipose tissue (WAT). Nevertheless, the endocrine actions of CCK on WAT remain unknown. Our goal was to investigate the role of CCK in regulating the production of adiponectin, an adipokine expressed in WAT, which is pivotal in preserving energy homeostasis.

EXPERIMENTAL APPROACH

The effect of the bioactive CCK fragment CCK-8 on adiponectin production was studied both in vivo and in vitro. CCK-8 effects were characterized in rats treated with selective CCK₁ and CCK₂ receptor antagonists as well as in pre-adipocytes carrying the selective silencing of either CCK₁ or CCK₂ receptors. The influence of insulin on CCK-8 responses was also analysed.

KEY RESULTS

In WAT, CCK-8 increased plasma adiponectin levels and the expression of the adiponectin gene (Adipoq). In pre-adipocytes, CCK-8 up-regulated adiponectin production. CCK-8 effects were abolished by L-365,260, a selective CCK₂ receptor antagonist. CCK₂ receptor knockdown also abolished the effects of CCK-8 in pre-adipocytes. Moreover, in vitro CCK-8 effects were blocked by triciribine, a specific inhibitor of protein kinase B (Akt) and by the PPARγ antagonist T0070907. Silencing the expression of the insulin receptor inhibited CCK-8-induced Adipoq expression in pre-adipocytes. Furthermore, insulin potentiated the effect of CCK-8.

CONCLUSION AND IMPLICATIONS

CCK-8 stimulates adiponectin production in WAT by acting on CCK₂ receptors, through a mechanism involving both Akt and PPARγ. Moreover, CCK-8 actions are only observed in the presence of insulin. Our results could have translational value in the design of new insulin-sensitizing therapies.

Potential Adiponectin Receptor Response Modifier Therapeutics

Many human diseases may benefit from adiponectin replacement therapy, but due to pharmacological disadvantages of the intact protein, druggable options focus on peptidic, and small molecule agonists of the adiponectin receptor. Peptide-based adiponectin replacement drug leads are derived from, or resemble, the active site of globular adiponectin. ADP355, the first-in-class such peptide, exhibits low nanomolar cellular activities, and clinically acceptable efficacies in a series of fibrotic and inflammation-derived diseases. The advantage of small molecule therapies, spearheaded by AdipoRon, is oral availability and extension of utility to a series of metabolic conditions. It is exactly the difficulties in the reliability and readout of the in vitro measures and the wealth of in vivo models that make comparison of the various drug classes complicated, if not impossible. While only a fewer number of maladies could take advantage of adiponectin receptor antagonists, the limited number of these available can be very useful tools in target validation studies. Alternative approaches to direct adiponectin signaling control use upstream adiponectin production inducing therapies but currently these offer relatively limited success compared to direct receptor agonists.