Plasma apolipoprotein M predicts overall survival in metastatic breast cancer patients.

PURPOSE: Apolipoprotein M (APOM) is a plasma apolipoprotein closely involved with lipid metabolism and inflammation. In vitro studies suggest that APOM may also have a tumor-suppressive role in breast cancer. In the present study, we aimed to evaluate the impact of plasma APOM levels on the prognosis of breast cancer patients. METHODS: We measured APOM levels using an enzyme-linked immunosorbent assay in 75 patients with ER-positive/HER2-negative metastatic breast cancer. The endpoint was overall survival (OS) at 24 months. RESULTS: During the 24-month follow-up period, 34.7% of the patients died. Baseline APOM levels were significantly reduced in patients who deceased during follow-up compared to survivors (42.7 ± 14.5 µg/mL versus 52.2 ± 13.8 µg/mL; P = 0.003). Cox regression analysis showed a hazard ratio of 0.30 [95% confidence interval 0.15-0.61]; P < 0.001 per doubling of APOM levels. Correction for age, C-reactive protein, menopausal state, histology of the primary tumor, metastatic site, number of metastases, endocrine resistance, scheduled therapy line, and kind of scheduled therapy indicated that circulating APOM predicted OS independently of these parameters (HRper doubling = 0.23 [0.09-0.56; P = 0.001). CONCLUSIONS: Our study suggests that circulating APOM is significantly linked with reduced mortality in metastatic breast cancer patients.

ApoM suppresses kidney renal clear cell carcinoma growth and metastasis via the Hippo-YAP signaling pathway.

Renal cell carcinoma is one of the most common malignancies worldwide, and kidney renal clear cell carcinoma (KIRC) is the most common histopathological type of renal cell carcinoma. However, the mechanism of KIRC progression remains poorly understood. Apolipoprotein M (ApoM) is a plasma apolipoprotein and a member of the lipid transport protein superfamily. Lipid metabolism is essential for tumor progression, and its related proteins can be used as therapeutic targets for tumors. ApoM influences the development of several cancers, but its relationship with KIRC remains unclear. In this study, we aimed to investigate the biological function of ApoM in KIRC and to reveal its potential molecular mechanisms. We found that ApoM expression was significantly reduced in KIRC and was strongly correlated with patient prognosis. ApoM overexpression significantly inhibited KIRC cell proliferation in vitro, suppressed the epithelial mesenchymal transition (EMT) of KIRC cells, and decreased their metastatic capacity. Additionally, the growth of KIRC cells was inhibited by ApoM overexpression in vivo. In addition, we found that overexpression of ApoM in KIRC attenuated Hippo-YAP protein expression and YAP stability and thus inhibited KIRC growth and progression. Therefore, ApoM may be a potential target for the treatment of KIRC.

Apolipoprotein M supports S1P production and conservation and mediates prolonged Akt activation via S1PR1 and S1PR3.

Sphingosine 1-phosphate (S1P) is one of the lipid mediators involved in diverse physiological functions. S1P circulates in blood and lymph bound to carrier proteins. Three S1P carrier proteins have been reported, albumin, apolipoprotein M (ApoM) and apolipoprotein A4 (ApoA4). The carrier-bound S1P exerts its functions via specific S1P receptors (S1PR1-5) on target cells. Previous studies showed several differences in physiological functions between albumin-bound S1P and ApoM-bound S1P. However, molecular mechanisms underlying the carrier-dependent differences have not been clarified. In addition, ApoA4 is a recently identified S1P carrier protein, and its functional differences from albumin and ApoM have not been addressed. Here, we compared the three carrier proteins in the processes of S1P degradation, release from S1P-producing cells and receptor activation. ApoM retained S1P more stable than albumin and ApoA4 in the cell culture medium when compared in the equimolar amounts. ApoM facilitated theS1P release from endothelial cells most efficiently. Furthermore, ApoM-bound S1P showed a tendency to induce prolonged activation of Akt via S1PR1 and S1PR3. These results suggest that the carrier-dependent functional differences of S1P are partly ascribed to the differences in the S1P stability, S1P-releasing efficiency and signaling duration.

Sphingosine 1-Phosphate and Apolipoprotein M Levels and Their Correlations with Inflammatory Biomarkers in Patients with Untreated Familial Hypercholesterolemia.

High-density lipoprotein (HDL)-bound apolipoprotein M/sphingosine 1-phosphate (ApoM/S1P) complex in cardiovascular diseases serves as a bridge between HDL and endothelial cells, maintaining a healthy endothelial barrier. To date, S1P and ApoM in patients with untreated heterozygous familial hypercholesterolemia (HeFH) have not been extensively studied. Eighty-one untreated patients with HeFH and 32 healthy control subjects were included in this study. Serum S1P, ApoM, sCD40L, sICAM-1, sVCAM-1, oxLDL, and TNFα concentrations were determined by ELISA. PON1 activities were measured spectrophotometrically. Lipoprotein subfractions were detected by Lipoprint. We diagnosed FH using the Dutch Lipid Clinic Network criteria. Significantly higher serum S1P and ApoM levels were found in HeFH patients compared to controls. S1P negatively correlated with large HDL and positively with small HDL subfractions in HeFH patients and the whole study population. S1P showed significant positive correlations with sCD40L and MMP-9 levels and PON1 arylesterase activity, while we found significant negative correlation between sVCAM-1 and S1P in HeFH patients. A backward stepwise multiple regression analysis showed that the best predictors of serum S1P were large HDL subfraction and arylesterase activity. Higher S1P and ApoM levels and their correlations with HDL subfractions and inflammatory markers in HeFH patients implied their possible role in endothelial protection.

Propofol promotes migration, alleviates inflammation, and apoptosis of lipopolysaccharide-induced human pulmonary microvascular endothelial cells by activating PI3K/AKT signaling pathway via upregulating APOM expression.

Propofol (PRO), a clinical potent intravenous anesthetic, plays a significant role in relieving inflammatory diseases by repressing the release of inflammatory cytokines. The present study was aimed to reveal a novel mechanism by which PRO alleviates acute lung injury (ALI). Lipopolysaccharide (LPS) was utilized to induce human pulmonary microvascular endothelial cells (HPMECs) so as to simulate the microenvironment of ALI, and the expression of apolipoprotein M (APOM) was examined with western blotting. Then, APOM was silenced and profopol was used to treat the LPS-injured HPMECs. The cell viability, migration, and apoptosis were respectively observed after the processes of cell counting kit-8, wound healing, transwell, and TUNEL assay. Meanwhile, the inflammatory response was detected by determining the contents of inflammatory cytokines. Subsequently, the relationship between phosphoinositide-3 kinase (PI3K)/protein kinase B (AKT) signaling pathway and PRO was analyzed by western blotting. PI3K/AKT inhibitor LY294002 was employed to evaluate whether the effects of PRO on LPS-challenged HPMECs injury were mediated by this pathway. Results revealed that APOM was notably downregulated in HPMECs after LPS exposure. PRO treatment promoted cell proliferation and migration while alleviated inflammation and apoptosis of LPS-treated HPMECs, which was reversed by APOM-downregulation. PRO brought about the upregulation of proteins in PI3K/AKT signaling pathway, and LY294002 intervention further accentuated the impacts of APOM-knockdown on LPS-challenged HPMECs injury. To conclude, PRO promotes migration and alleviates inflammation and apoptosis of LPS-treated HPMECs by PI3K/AKT signaling pathway via upregulating APOM, which laid an experimental foundation for the future study and clinical application of PRO.

The effects and possible mechanism of action of apolipoprotein M on the growth of breast cancer cells.

BACKGROUND: To investigate the effects and mechanism of action of apolipoprotein M (ApoM) on the growth of breast cancer (BC) cells. METHODS AND RESULTS: Bioinformatics, cell experiments and animal experiments were used to verify the effect of ApoM on breast cancer cell lines and breast tumor growth in vivo. ApoM expression was significantly reduced in BC tissues, and patients with lower ApoM mRNA expression had a poorer prognosis (P < 0.0001). Besides, ApoM can partially inhibit the proliferative, migratory and invasive processes of BC cells. In vivo, the difference between ApoM-OE and NC groups was no significant. The level of vitamin D receptor (VDR) protein in MDA-MB-231 cells was increased by overexpression of ApoM (P < 0.05), while in MCF-7 cells, VDR levels decreased (P < 0.05). CONCLUSIONS: ApoM can partially inhibit the growth of BC cells. VDR may play a role, but is not the main pathway.

Isoform-Dependent Effects of Apolipoprotein E on Sphingolipid Metabolism in Neural Cells.

BACKGROUND: Sphingosine 1-phosphate (S1P) and ceramides have been implicated in the development of Alzheimer's disease. Apolipoprotein E (ApoE) isoforms are also involved in the development of Alzheimer's disease. OBJECTIVE: We aimed at elucidating the potential association of the ApoE isoforms with sphingolipid metabolism in the central nervous system. METHODS: We investigated the modulations of apolipoprotein M (apoM), a carrier of S1P, S1P, and ceramides in Apoeshl mice, which spontaneously lack apoE, and U251 cells and SH-SY5Y cells infected with adenovirus vectors encoding for apoE2, apoE3, and apoE4. RESULTS: In the brains of Apoeshl mice, the levels of apoM were lower, while those of ceramides were higher. In U251 cells, cellular apoM and S1P levels were the highest in the cells overexpressing apoE2 among the apoE isoforms. The cellular and medium contents of ceramides decreased in the order of the cells overexpressing apoE3 > apoE2 and increased in the cells overexpressing apoE4. In SH-SY5Y cells, apoM mRNA and medium S1P levels were also the highest in the cells overexpressing apoE2. The cellular contents of ceramides decreased in the order of the cells overexpressing apoE3 > apoE2 = apoE4 and those in medium decreased in the order of the cells overexpressing apoE3 > apoE2, while increased in the cells overexpressing apoE4. CONCLUSION: The modulation of apoM and S1P might partly explain the protective effects of apoE2 against Alzheimer's disease, and the modulation of ceramides might be one of the mechanisms explaining the association of apoE4 with the development of Alzheimer's disease.

Plasma components to protect the endothelial barrier after shock: A role for sphingosine 1-phosphate.

BACKGROUND: Hemorrhagic shock leads to endothelial glycocalyx shedding, endothelial cellular inflammation, and increased vascular permeability. Early plasma administration improves survival in severely injured patients; this may be due in part to its ability to ameliorate this trauma-induced endotheliopathy. The protective effect of early plasma administration may be due to its sphingosine 1-phosphate content. Principle carriers of plasma sphingosine 1-phosphate include apolipoprotein M and albumin. The relative roles of these carriers on sphingosine 1-phosphate protective effects are unknown and were studied in an in vitro model of microcirculation. METHODS: Endothelial cell monolayers were established in microfluidic perfusion devices and exposed to control or biomimetic shock conditions. Sphingosine 1-phosphate, albumin + sphingosine 1-phosphate, or apolipoprotein M + sphingosine 1-phosphate were added later to the perfusate. Biomarkers of endothelial and glycocalyx activation and damage were then determined. RESULTS: Sphingosine 1-phosphate preserved endothelial and glycocalyx barrier function after exposure to conditions of shock in the microcirculation. The protective effect was related to sphingosine 1-phosphate chaperones; the apolipoprotein M loaded with sphingosine 1-phosphate had the most profound effect. CONCLUSION: Carrier-based sphingosine 1-phosphate may be a useful adjunct in early hemorrhagic shock resuscitation.

Adipose-Derived Lipid-Binding Proteins: The Good, the Bad and the Metabolic Diseases.

Adipose tissue releases a large range of bioactive factors called adipokines, many of which are involved in inflammation, glucose homeostasis and lipid metabolism. Under pathological conditions such as obesity, most of the adipokines are upregulated and considered as deleterious, due to their pro-inflammatory, pro-atherosclerotic or pro-diabetic properties, while only a few are downregulated and would be designated as beneficial adipokines, thanks to their counteracting properties against the onset of comorbidities. This review focuses on six adipose-derived lipid-binding proteins that have emerged as key factors in the development of obesity and diabetes: Retinol binding protein 4 (RBP4), Fatty acid binding protein 4 (FABP4), Apolipoprotein D (APOD), Lipocalin-2 (LCN2), Lipocalin-14 (LCN14) and Apolipoprotein M (APOM). These proteins share structural homology and capacity to bind small hydrophobic molecules but display opposite effects on glucose and lipid metabolism. RBP4 and FABP4 are positively associated with metabolic syndrome, while APOD and LCN2 are ubiquitously expressed proteins with deleterious or beneficial effects, depending on their anatomical site of expression. LCN14 and APOM have been recently identified as adipokines associated with healthy metabolism. Recent findings on these lipid-binding proteins exhibiting detrimental or protective roles in human and murine metabolism and their involvement in metabolic diseases are also discussed.

Apolipoprotein M promotes cholesterol uptake and efflux from mouse macrophages.

Apolipoprotein M (ApoM) exhibits various anti-atherosclerotic functions as a component of high-density lipoprotein (HDL) particles. Scavenger receptor class B type I (SR-BI) is a classic HDL receptor that mediates selective cholesterol uptake and enhances the efflux of cellular cholesterol to HDL. However, the effect of ApoM on cholesterol transport in macrophages remains unclear. In this study, we identified for the first time that ApoM is expressed in mouse macrophages and is involved in cholesterol uptake, similar to SR-BI. NBD-cholesterol uptake and efflux in cells were characterized using fluorescence spectrophotometry. The uptake ratios of cholesterol by macrophages from ApoM-/- SR-BI-/- mice were significantly lower than those from ApoM+/+ SR-BI-/- and ApoM-/- SR-BI+/+ mice. Real-time fluorescence quantitative PCR was used to analyze the expression of cholesterol transport-related genes involved in cholesterol uptake. ApoM-enriched HDL (ApoM+ HDL) facilitated more cholesterol efflux from murine macrophage Ana-1 cells than ApoM-free HDL (ApoM- HDL). However, recombinant human ApoM protein inhibited the ability of ApoM- HDL to induce cholesterol efflux. In conclusion, ApoM promotes cholesterol uptake and efflux in mouse macrophages. A better understanding of ApoM function may lead to the development of novel therapeutic strategies for treating atherosclerotic diseases.

Revealing the Role of High-Density Lipoprotein in Colorectal Cancer.

Colorectal cancer (CRC) is a highly prevalent malignancy with multifactorial etiology, which includes metabolic alterations as contributors to disease development. Studies have shown that lipid status disorders are involved in colorectal carcinogenesis. In line with this, previous studies have also suggested that the serum high-density lipoprotein cholesterol (HDL-C) level decreases in patients with CRC, but more recently, the focus of investigations has shifted toward the exploration of qualitative properties of HDL in this malignancy. Herein, a comprehensive overview of available evidences regarding the putative role of HDL in CRC will be presented. We will analyze existing findings regarding alterations of HDL-C levels but also HDL particle structure and distribution in CRC. In addition, changes in HDL functionality in this malignancy will be discussed. Moreover, we will focus on the genetic regulation of HDL metabolism, as well as the involvement of HDL in disturbances of cholesterol trafficking in CRC. Finally, possible therapeutic implications related to HDL will be presented. Given the available evidence, future studies are needed to resolve all raised issues concerning the suggested protective role of HDL in CRC, its presumed function as a biomarker, and eventual therapeutic approaches based on HDL.

Apolipoprotein M inhibits proliferation and migration of larynx carcinoma cells.

Prior studies have shown that apolipoprotein M (APOM) is involved in the development of some cancers. Here we investigated the effects of APOM on larynx cancer (LC). 20 patients with vocal cord polyps and 18 patients with LC were included in this study. The protein and mRNA levels of the samples were analysed using the Wes-ProteinSimple system (or traditional Western blot) and PCR technology, respectively. APOM protein level in cancer tissues was lower than that in paracarcinomatous (P = 0.0003) and polyp tissues (P < 0.0001). APOM overexpression significantly inhibited TU686 cell proliferation (P < 0.0001) and migration (P < 0.01), and increased expression of vitamin D receptor (VDR, P < 0.0001) as well as nuclear factor erythroid 2-like 3 (NFE2L3, P = 0.0215). In addition, matrix metalloproteinase-10 (MMP-10) mRNA level was significantly reduced in the APOM overexpression group (P = 0.0077). However, Western blot analysis showed that APOM overexpression did not change VDR, NFE2L3 and MMP-10 protein levels (P > 0.05). In summary, APOM inhibits the proliferation and migration of LC cells, but may not be related to VDR, NFE2L3 and MMP-10, which needs further study.

The apoM-S1P axis in hepatic diseases.

Liver dysfunction is always accompanied by lipid metabolism dysfunction. Apolipoprotein M (apoM), a member of the apolipoprotein family, is primarily expressed and secreted from the liver. apoM is the main chaperone of sphingosine-1-phosphate (S1P), a small signalling molecule associated with numerous physiologic and pathophysiologic processes. In addition to transport, apoM also influences the biologic effects of S1P. Most recently, numerous studies have investigated the potential role of the apoM-S1P axis in a variety of hepatic diseases. These include liver fibrosis, viral hepatitis B and C infection, hepatobiliary disease, non-alcoholic and alcoholic steatohepatitis, acute liver injury and hepatocellular carcinoma. In this review, the roles of apoM and S1P in the development of hepatic diseases are summarized, and novel insights into the diagnosis and treatment of hepatic diseases are discussed.

Berberine reduces gut-vascular barrier permeability via modulation of ApoM/S1P pathway in a model of polymicrobial sepsis.

AIMS: The hyperpermeability of gut-vascular barrier (GVB) plays a role in gut-derived sepsis. The goal of this study was to evaluate if berberine might improve hepatic apolipoprotein M (ApoM) generation and raise plasma ApoM level to protect the compromised GVB. MATERIALS AND METHODS: The compromised GVB was induced by sepsis. Hepatic ApoM mRNA and phosphoenolpyruvate carboxykinase (PEPCK) mRNA and plasma ApoM level were assayed by qRT-PCR and ELISA, respectively. The permeability of intestinal capillary in vivo and of rat intestinal microvascular endothelial cells (RIMECs) in vitro was assayed by FITC-dextran. The blood glucose was detected by a glucometer. Plasma insulin, TNF-α and IL-1ß were assayed by ELISA. The plasmalemma vesicle-associated protein-1 (PV1), ß-catenin and occludin in RIMECs were assayed by Western blot. KEY FINDINGS: Sepsis decreased hepatic ApoM mRNA and plasma ApoM level, but raised hepatic PEPCK mRNA and plasma glucose, insulin, TNF-α, and IL-1ß levels. The increased vascular endothelial permeability was abrogated by recombinant rat ApoM in vivo or ApoM-bound S1P in vitro. ApoM-bound S1P decreased PV1 but increased occludin and ß-catenin expression in LPS-treated RIMECs. Berberine in a dose-dependent manner raised hepatic ApoM mRNA and plasma ApoM level, but decreased septic hyperglycemia, insulin resistance and plasma TNF-α and IL-1ß levels. Berberine reduced sepsis-induced PEPCK and TLR4 mRNA overexpression in the liver. SIGNIFICANCE: This study demonstrated berberine inhibited TLR4-mediated hyperglycemia, insulin resistance and proinflammatory molecule production, thereby increasing ApoM gene expression and plasma ApoM. Berberine protected the damaged GVB via modulation of ApoM/S1P pathway.

Modulation of sphingosine 1-phosphate by hepatobiliary cholesterol handling.

Hepatobiliary cholesterol handling, mediated by Niemann-Pick C1-like 1 protein (NPC1L1) and ABCG5/8, is well-known to contribute to the homeostasis of cholesterol. We attempted to elucidate the impact of hepatobiliary cholesterol handling on the homeostasis of sphingolipids and lysophospholipids, especially sphingosine 1-phosphate (S1P). We induced the overexpression of NPC1L1 or ABCG5/8 in the mouse liver. Hepatic NPC1L1 overexpression increased the plasma and hepatic S1P levels, while it decreased the biliary S1P levels, and all of these changes were inhibited by ezetimibe. The ability of HDL to activate Akt in the endothelial cells was augmented by hepatic NPC1L1 overexpression. NPC1L1-mediated S1P transport was confirmed by both in vitro and in vivo studies conducted using C17 S1P, an exogenous S1P analog. Upregulation of apolipoprotein M (apoM) was involved in these modulations, although apoM was not necessary for these modulations. Moreover, the increase in the plasma S1P levels also observed in ABCG5/8-overexpressing mice was dependent on the elevation of the plasma apoM levels. In regard to other sphingolipids and lysophospholipids, ceramides were similarly modulated by NPC1L1 to S1P, while other lipids were differently influenced by NPC1L1 or ABCG5/8 from S1P. Hepatobiliary cholesterol handling might also regulate the functional lipids, such as S1P.

Increased expression levels of inflammatory cytokines and adhesion molecules in lipopolysaccharide­induced acute inflammatory apoM­/­ mice.

Apolipoprotein M (apoM) may serve a protective role in the development of inflammation. Nuclear factor­κB (NF­κB) and its downstream factors (including a number of inflammatory cytokines and adhesion molecules) are essential for the regulation of inflammatory processes. In the present study, the importance of apoM in lipopolysaccharide (LPS)­induced acute inflammation and its potential underlying mechanisms, were investigated using an apoM­knockout mouse model. The levels of inducible nitric oxide synthase (iNOS), NF­κB, interleukin (IL)­1ß, intercellular adhesion molecule 1 (ICAM­1) and vascular cell adhesion protein 1 (VCAM­1) were detected using reverse transcription­quantitative PCR and western blotting. The serum levels of IL­6 and IL­10 were detected using Luminex technology. The results demonstrated that the protein levels of iNOS, NF­κB, IL­1ß, ICAM­1 and VCAM­1 were significantly increased in apoM­/­ mice compared with those in apoM+/+ mice. In addition, two­way ANOVA revealed that the interaction between apoM and LPS had a statistically significant effect on a number of factors, including the mRNA expression levels of hepatic iNOS, NF­κB, IL­1ß, ICAM­1 and VCAM­1. Notably, the effects of apoM and 10 mg/kg LPS on the levels of IL­6 and IL­10 were the opposite of those induced by 5 mg/kg LPS, which could be associated with the dual anti­ and pro­inflammatory effects of IL­6 and IL­10. Collectively, the results of the present study revealed that apoM is an important regulator of inflammatory cytokine and adhesion molecule production in LPS­induced inflammation, which may consequently be associated with the severity of inflammation. These findings indicated that the anti­inflammatory effects of apoM may partly result from the inhibition of the NF­κB pathway.

HDL-S1P protects endothelial function and reduces lung injury during sepsis in vivo and in vitro.

OBJECTIVE: In sepsis, the protection of the vascular endothelium is essential and the maintenance of its function is critical to prevent further deterioration. High-density lipoprotein (HDL)-associated sphingosine-1-phosphate (S1P) is a bioactive lipid in plasma and its role in sepsis has not been extensively studied. This study aimed to investigate the effects of HDL-S1P on sepsis in cellular and animal models, as well as human plasma samples. MEASUREMENTS: We established an animal model of sepsis with different severities achieved by caecal ligation and puncture (CLP) and lipopolysaccharide (LPS) injection, and then explored the relationship between HDL-S1P and lung endothelial dysfunction in vivo. To determine the effects of HDL-S1P in the pulmonary endothelium of septic rats, we then injected HDL-S1P into septic rats to find out if it can reduce the lung injury caused by sepsis. Further, we explored the mechanism in vitro by studying the role of S1P-specific receptor agonists and inhibitors in LPS-stimulated human umbilical vein endothelial cells. We also explored the relationship between plasma HDL-S1P content and sepsis severity in septic patients by analysing their plasma samples. RESULTS: HDL-S1P concentrations in plasma were negatively correlated with endothelial functional damage in sepsis, both in the animal model and in the septic patients in our study. In vivo, HDL-S1P injection significantly reduced pulmonary oedema and endothelial leakage in septic rats. In vitro, cell experiments showed that HDL-S1P effectively protected the proliferation and migration abilities of endothelial cells, which could be partly explained by its biased activation of the S1P receptor 1. CONCLUSION: Our study preliminary explored the function of HDL-S1P in sepsis in cellular and animal models, as well as human subjects. The results indicate HDL-S1P protected endothelial functions in septic patients. Thus, it has therapeutic potential and can be used for the clinical treatment of sepsis.

LncRNA TUG1 regulates ApoM to promote atherosclerosis progression through miR-92a/FXR1 axis.

This study aims to explore the possible mechanism of TUG1 regulating ApoM in AS. To this end, expression levels of TUG1 and ApoM were measured in high fat dieted C57BL/6J mice, normal dieted C57BL/6J mice, ob/ob mice and db/db mice. LV-TUG1 or sh-TUG1 was injected into C57BL/6J mice before isolating peritoneal macrophages to measure cholesterol efflux (CE) and expression levels of ABCA1, ABCG1 and SR-BI. Meanwhile, CE in RAW264.7 cells was also measured after cell transfection. Dual luciferase reporter assay and anti-AGO2 RIP were applied to verify the relationship among TUG1, FXR1 and miR-92a. Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterin (LDL-C), high-density lipoprotein cholesterol (HDL-C) as well as expressions of inflammatory cytokines (TNF-α, IL-1ß and IL-6) in plasma were measured. Knock-down or expressed TUG1, FXR1 or miR-92a in NCTC 1469 cells or in ApoE-/- AS mice to determine the alteration on ApoM and plaque size. TUG1 was highly expressed while ApoM was down-regulated in high fat dieted C57BL/6J mice, b/ob and db/db mice. Overexpression of TUG1 could reduce the expression of ApoM, ABCA1 and ABCG1 in addition to slowing down CE rate. Reversed expression pattern was found in cells with knock-down of TUG1. TUG1 can compete with FXR1 to bind miR-92a. FXR1 negatively target ApoM. Overexpression of TUG1 in ApoE-/- mice can increase plaque size and enhance macrophage contents accordingly. TUG1 can inhibit ApoM in both liver tissues and plasma to inhibit CE through regulating miR-92a/ FXR1 axis. TUG1 is a promising target for AS treatment.

LncRNA HCG11 suppresses laryngeal carcinoma cells progression via sponging miR-4469/APOM axis.

OBJECTIVE: Longnon-coding RNAs (lncRNAs) have been reported to participate in the regulatory mechanisms of various cancers. Therefore, the aim of this study was to investigate the functional role of lncRNA HLA complex group 11 (HCG11) in laryngeal carcinoma. MATERIALS AND METHODS: The laryngeal carcinoma cell lines SNU46, SNU899, AMC-HN-8, and normal human nasopharyngeal epithelial cells NP69 were purchased. The expression of HCG11, miR-4469, and apolipoprotein M (APOM) was detected by quantitative Real Time-PCR (qRT-PCR) in tissues and cells. Cell proliferation was detected by Cell Counting Kit-8 (CCK-8) assay and colony formation assays. The protein expression of Bax and Bcl-2 was detected by Western blot. Besides, the mechanism assays were conducted to observe the interaction between miR-449 and HCG11 or APOM. The apoptosis in each group was detected by TUNEL assay. RESULTS: In this research, low expression of HCG11 was discovered in laryngeal carcinoma tissues and cells. Overexpression of HCG11 retarded cell proliferation and enhanced cell apoptosis. Later, we found that APOM was also downregulated in laryngeal carcinoma tissues and cell lines, and inhibited laryngeal carcinoma progression. HCG11 positively regulated APOM at the post-transcriptional level. MiR-4469 was predicted to have the binding sites of HCG11 and APOM. Furthermore, it was demonstrated that HCG11 absorbed miR-4469 to upregulate APOM expression. Finally, it was indicated that the repression of APOM rescued the effects of HCG11 overexpression on cell proliferation and cell apoptosis. CONCLUSIONS: This study uncovered that HCG11 sponged miR-4469 to suppress laryngeal carcinoma progression by upregulating APOM expression.

Apolipoprotein M overexpression through adeno-associated virus gene transfer improves insulin secretion and insulin sensitivity in Goto-Kakizaki rats.

AIMS/OBJECTIVE: The development of type 2 diabetes is a result of insulin resistance in various tissues, including skeletal muscle and liver. Apolipoprotein M (ApoM) plays an important role in the function of high-density lipoprotein, and also affects hepatic lipid and glucose metabolism. In this study, we aimed to investigate whether ApoM overexpression modulates glucose metabolism and improves insulin sensitivity. MATERIALS AND METHODS: The Goto-Kakizaki (GK) rats were transfected with adeno-associated virus (AAV) encoding rat ApoM gene or control blank. The oral glucose tolerance test (OGTT) and hyperinsulinemic-euglycemic clamp (HEC) experiment were used to assess the insulin sensitivity of GK rats. RESULTS: The results show that ApoM messenger ribonucleic acid and protein were significantly overexpressed in the pancreatic tissues. Overexpression of ApoM decreased fasting blood glucose and random blood glucose, improved glucose tolerance, and increased bodyweight and insulin levels in GK rats. The glucose infusion rate of rats in the AAV encoding rat ApoM gene group during HEC test was 1.04-, 1.23- and 1.95-fold higher than that in the AAV control blank group at 1-3 weeks after injection of AAV, respectively. A Wes-ProteinSimple assay and quantification was carried out to assess phosphorylated protein kinase B/protein kinase B protein levels in the muscle tissues of ApoM-overexpressing GK rats, and they were found to be higher than those of the control group at the seventh week after AAV injection. CONCLUSIONS: ApoM overexpression through adeno-associated virus gene transfer might improve insulin secretion and insulin sensitivity in GK rats.