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Results for “MESSENGER-RNA”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 361 records · Page 20
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DOE OSTI2018

Crucial role of HO-1/IRF4-dependent apoptosis induced by panobinostat and lenalidomide in multiple myeloma

Highlights: • Panobinostat led to downregulation of HO-1/IRF4/MYC mRNA and protein expressions. • The relationship between HO-1 and IRF4/MYC expressions in MM cells was analyzed. • IRF4 downregulation caused panobinostat-induced histone H3K9 acetylation. • Panobinostat synergized with lenalidomide by blocking the HO-1/IRF4/MYC axis. • Panobinostat reversed the MM cell resistance to lenalidomide partly due to IRF4. Inhibition of histone deacetylase (HDAC) is a promising therapeutic strategy for various hematologic cancers. Panobinostat has been approved for treating patients with multiple myeloma (MM) by the FDA. Since the mechanism for the resistance of panobinostat to MM remains elusive, we aimed to clarify this mechanism and the synergism of panobinostat with lenalidomide. The mRNA and protein of transcription factor IRF4 were overexpressed in CD138{sup +} mononuclear cells from MM patients compared with in those from healthy donors. Given that direct IRF4 inhibitors are clinically unavailable, we intended to explore the mechanism by which IRF4 expression was regulated in MM. Heme oxygenase-1 (HO-1) promotes the growth and drug resistance of various malignant tumors, and its expression is positively correlated with IRF4 mRNA and protein expression levels. Herein, panobinostat induced acetylation of histone H3K9 and activation of caspase-3 in MM cells, being inversely correlated with the reduction of HO-1/IRF4/MYC protein levels. Adding Z-DEVD-FMK, a caspase-3 inhibitor, abolished the HO-1/IRF4 reduction by panobinostat alone or in combination with lenalidomide, suggesting that caspase-3-mediated HO-1/IRF4/MYC degradation occurred. Given that lenalidomide stabilized cereblon and facilitated IRF4 degradation in MM cells, we combined it with LBH589, an HDAC inhibitor. LBH589 and lenalidomide exerted synergistic effects, and LBH589 reversed the efficacy of lenalidomide on the resistance of CD138{sup +} primary MM cells, in part due to simultaneous suppression of HO-1, IRF4 and MYC. The results provide an eligible therapeutic strategy for targeting MM depending on the IRF4 network and clinical testing of this drug combination in MM patients.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

E4BP4 inhibits AngII-induced apoptosis in H9c2 cardiomyoblasts by activating the PI3K-Akt pathway and promoting calcium uptake

Highlights: • E4BP4 expression in H9c2 significantly attenuates AngII-induced apoptosis. • E4BP4 inhibits AngII-induced IGF-II expression & caspase cleavage through PI3K-Akt pathway. • E4BP4 enhances calcium reuptake into SR by up-regulating p-PKA and p-PLB proteins. • E4BP4 thus acts as a survival factor in H9c2, regulating IGF-II and calcium cycling. The bZIP transcription factor E4BP4 is a survival factor that is known to be elevated in diseased heart and promote cell survival. In this study the role of E4BP4 on angiotensin-II (AngII)-induced apoptosis has been examined in in vitro cell model. H9c2 cardiomyoblast cells that overexpressed E4BP4 were exposed to AngII to observe the cardio-protective effects of E4BP4 on hypertension related apoptosis. The results from TUNEL assays revealed that E4BP4 significantly attenuated AngII-induced apoptosis. Further analysis by Western blot and RT-PCR showed that E4BP4 inhibited AngII-induced IGF-II mRNA expression and cleavage of caspase-3 through the PI3K-Akt pathway. In addition, E4BP4 enhanced calcium reuptake into the sacroplasmic reticulum by down-regulating PP2A and by up-regulating the phosphorylation of PKA and PLB proteins. Our findings indicate that E4BP4 functions as a survival factor in cardiomyoblasts by inhibiting IGF-II transcription and by regulating calcium cycling.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Up-regulated lncRNA-MSX2P1 promotes the growth of IL-22-stimulated keratinocytes by inhibiting miR-6731-5p and activating S100A7

Highlights: • High expression of MSX2P1 and S100A7 in psoriatic lesion tissues. • MSX2P1, functions as miR-6731-5p sponge, modulates S100A7 expression. • miR-6731-5p inhibits the progression of IL-22-stimulated keratinocytes by S100A7. Competitive endogenous RNAs (ceRNAs) regulate RNA transcripts by competing for shared miRNAs and play critical roles in disease development. Psoriasis is a long-lasting, recurring chronic inflammatory skin disease characterized by hyperproliferation of keratinocytes. The keratinocyte response is triggered by the activation of inflammatory cytokines, like interleukin-22 (IL-22). We used lncRNA array analysis to detect differentially expressed lncRNAs in skin (HaCaT) cells treated with or without IL-22. We used hematoxylin and eosin (H&E) staining to determine the pathological changes in skin cells and immunohistochemistry to evaluate the expression of S100A7. We used qRT-PCR and Western blotting to detect the expression levels of MSX2P1 and S100A7. We down-regulated the expression of MSX2P1 by infecting with lentiviral-vector shRNA. We measured cell proliferation, cell cycle status, and apoptosis by the CCK-8 assay, flow cytometry, and Annexin Ⅴ-FITC/PI staining, respectively. In addition, we used the luciferase reporter gene assay to determine the relationships between MSX2P1 or miR-6731-5p and S100A7, respectively. LncRNA array analysis revealed that 103 lncRNAs were up-regulated and 51 were down-regulated. Furthermore, qRT-PCR showed that the mRNAs levels of MSX2P1 was significantly altered in HaCaT cells treated with IL-22, compared with control cells; and MSX2P1 was mainly in the cytoplasm. Based on the IL-22-stimulated lncRNA-associated ceRNA network, we selected MSX2P1-miR-6731-5p-S100A7 for further study. H&E staining exhibited characteristic features specific to psoriatic lesions. Immunohistochemistry demonstrated significantly increased expression levels of S100A7 in psoriatic lesions, compared with normal skin tissue. We observed a positive correlation between lncRNA-MSX2P1 expression and S100A7 expression. In addition, miR-6731-5p suppressed proliferation, accelerated apoptosis in IL-22-stimulated keratinocytes, and decreased the expressions of S100A7, IL-12β, IL-23, HLA-C, CCHCR1, TNF-α, and NF-κB proteins. Our data demonstrated that MSX2P1 facilitate the progression and growth of IL-22-stimulated keratinocytes by inhibiting miR-6731-5p and activating S100A7. We speculate that the biological network of MSX2P1-miR-6731-5p-S100A7 is a potential novel therapeutic target for the future treatment of psoriasis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

The interaction between XBP1 and eNOS contributes to endothelial cell migration

Highlights: • Wound in EC monolayer induced XBP1 splicing, which was involved in EC migration. • XBP1s increased NOS3 mRNA stability via down-regulating microRNA miR-24. • ENOS was involved in EC migration via forming a complex with AKT and XBP1s. The X-box binding protein 1 (XBP1) is a pivotal transcription factor in the endoplasmic reticulum stress response. Our previous studies have proven that XBP1 is involved in vascular endothelial growth factor (VEGF)-mediated endothelial cell (EC) proliferation and angiogenesis. In this study, we used EC monolayer wound healing, tube formation and transwell migration models to explore the role of XBP1splicing in EC migration. We found that scratching on EC monolayer triggered XBP1splicing, which was attenuated by the presence of SU5416and LY294002, suggesting that VEGF signalling pathways may be involved. Over-expression of the spliced XBP1 (XBP1s) via Ad-XBP1s gene transfer increased while knockdown of IRE1αor XBP1 by ShRNA lentivirus suppressed EC migration. Over-expression of XBP1s up-regulated the nitric oxide synthase 3 (NOS3)mRNA through the 3’UTR-mediated stabilisation and increased eNOS protein translation. Further experiments demonstrated that miR-24 participated in the XBP1s-induced eNOSup-regulation and EC migration. Further co-IP and immunofluorescence staining assays revealed that protein kinase B (Akt), eNOS andXBP1s form a complex, resulting in Akt and eNOS nucleus relocation. These results suggest that XBP1 splicing can regulate eNOS expression and cellular location, leading to EC migration and therefore contributing to wound healing and angiogenesis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

microRNA-181a downregulates deptor for TGFβ-induced glomerular mesangial cell hypertrophy and matrix protein expression

Highlights: • TGFβ increases microRNA-181a to target deptor mRNA 3′UTR. • TGFβ-stimulated miR-181a activates Akt kinase to induce inactivating phosphorylation of mTORC1 inhibitors tuberin and PRAS40. • Increased miR-181a by TGFβ enhances mTORC1 activity via deptor downregulation. • TGFβ-induced miR-181a regulates phosphorylation of mRNA translation initiation and elongation factors. • miR-181a-targeted deptor regulates TGFβ-induced mesangial cell hypertrophy and matrix protein fibronectin expression. TGFβ contributes to mesangial cell hypertrophy and matrix protein increase in various kidney diseases including diabetic nephropathy. Deptor is an mTOR-interacting protein and suppresses mTORC1 and mTORC2 activities. We have recently shown that TGFβ-induced inhibition of deptor increases the mTOR activity. The mechanism by which TGFβ regulates deptor expression is not known. Here we identify deptor as a target of the microRNA-181a. We show that in mesangial cells, TGFβ increases the expression of miR-181a to downregulate deptor. Decrease in deptor augments mTORC2 activity, resulting in phosphorylation/activation of Akt kinase. Akt promotes inactivating phosphorylation of PRAS40 and tuberin, leading to stimulation of mTORC1. miR-181a-mimic increased mTORC1 and C2 activities, while anti-miR-181a inhibited them. mTORC1 controls protein synthesis via phosphorylation of translation initiation and elongation suppressors 4EBP-1 and eEF2 kinase. TGFβ-stimulated miR-181a increased the phosphorylation of 4EBP-1 and eEF2 kinase, resulting in their inactivation. miR-181a-dependent inactivation of eEF2 kinase caused dephosphorylation of eEF2. Consequently, miR-181a-mimic increased protein synthesis and hypertrophy of mesangial cells similar to TGFβ. Anti-miR-181a blocked these events in a deptor-dependent manner. Finally, TGFβ-miR-181a-driven deptor downregulation increased the expression of fibronectin. Our results identify a novel mechanism involving miR-181a-driven deptor downregulation, which contributes to mesangial cell pathologies in renal complications.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

LZ205, a newly synthesized flavonoid compound, exerts anti-inflammatory effect by inhibiting M1 macrophage polarization through regulating PI3K/AKT/mTOR signaling pathway

Highlights: • LZ205 reduced M1[HYPHEN]associated cytokines secretion without affecting M2 macrophages. • LZ205 significantly blocked expression of PI3K, p-Akt and p-mTOR in macrophages. • LZ205 significantly inhibited M1 macrophages polarization in DSS-induced colitis and alum-induced murine peritonitis. Macrophage polarization is involved in the process of inflammation. Regulation of macrophage polarization is considered to be an effective method for the treatment of various inflammatory diseases. In our study, we investigated the potential molecular mechanism of the flavonoid compound LZ205, which exhibits anti-inflammatory property. Results showed that LZ205 significantly reduced M1 macrophage-associated proinflammatory cytokines secretion by regulating PI3K/AKT/mTOR signaling pathway without affecting M2 macrophage-associated cytokines mRNA levels. In vivo studies showed that LZ205 significantly inhibited M1 macrophages polarization in DSS-induced colitis and alum-induced murine peritonitis. Consistent with in vitro studies, LZ205 significantly blocked expression of PI3K, p-AKT and p-mTOR in colon tissues and peritoneal macrophages. Taken together, LZ205 exerts anti-inflammatory effect by inhibiting M1 macrophage polarization via regulating PI3K/AKT/mTOR signaling pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

The EMT-related transcription factor snail up-regulates FAPα in malignant melanoma cells

Highlights: • The study finds a different regulation mechanism on FAPα expression. • Snail up-regulates expression of FAPα in malignant melanoma cells. • Snail binds to E-box in FAPα promoter to regulate FAPα expression. • Snail expression is positively correlated to FAPα expression in human cutaneous malignant melanoma. FAPα is a cell surface serine protease, mainly expressed in tumor stromal fibroblasts in more than 90% of human epithelial carcinomas. Due to its almost no expression in normal tissues and its tumor-promoting effects, FAPα has been studied as a novel potential target for antitumor therapy. However, the regulation mechanism on FAPα expression is poorly understood. In this study, we found that overexpression of snail significantly increased the mRNA and protein expression levels of FAPα in malignant melanoma B16 and SK-MEL-28 cells. Overexpression of snail increased FAPα promoter activity remarkably. Snail could directly bind to FAPα promoter to regulate FAPα expression. Moreover, snail expression was positively correlated to FAPα expression in human cutaneous malignant melanoma. Furthermore, knockdown of FAPα markedly reduced snail-induced cell migration. Overall, our findings provide a novel regulation mechanism on FAPα expression and highlight the role of snail/FAPα axis as a novel target for melanoma treatment.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Leucyl-tRNA synthetase is required for the myogenic differentiation of C2C12 myoblasts, but not for hypertrophy or metabolic alteration of myotubes

Highlights: • siRNA-mediated Lars knockdown blocked C2C12 myoblast differentiation into myotubes. • Lars knockdown decreased Igf2 mRNA expression from an early differentiation stage. • Lars knockdown decreased phosphorylated p70 S6 kinase but did not activate Akt. • Lars knockdown did not decrease phospho-mTOR nor affect hypertrophy or metabolism of myotube. Mammalian target of rapamycin (mTOR) signaling controls skeletal muscle cell differentiation, growth, and metabolism by sensing the intracellular energy status and nutrients. Recently, leucyl-tRNA synthetase (Lars) was identified as an intracellular sensor of leucine involved in the activation of mTOR signaling. However, there is still no evidence for the activation of mTOR signaling by Lars and its physiological roles in skeletal muscle cells. In this study, we determined the potential roles of Lars for the activation of mTOR signaling, skeletal muscle cell differentiation, hypertrophy, and metabolism using small interfering (si)-RNA knockdown. siRNA-mediated knockdown of Lars decreased phosphorylated p70 S6 kinase and inhibited the differentiation of C2C12 mouse myoblasts into myotubes, as evidenced by a decreased fusion index and decreased mRNA and protein expression levels of myogenic markers. Importantly, si-Lars decreased the level of Insulin-like growth factor 2 (Igf2) mRNA expression from the early stages of differentiation, indicating the possibility of an association between the mTOR–IGF2 axis and Lars. However, Lars knockdown did not decrease phosphorylated mTOR in differentiated myotubes, nor did it affect the hypertrophy of myotubes as evidenced by measuring their diameters and detecting the mRNA and protein expression of hypertrophy markers. Similarly, an extracellular flux analyzer showed that Lars knockdown did not affect the metabolism (glycolysis and mitochondrial respiration) of myotubes. These results demonstrate that Lars is required for skeletal muscle differentiation through the activation of mTOR signaling, but not for hypertrophy or metabolic alteration of myotubes.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Egr-1 mediated cardiac miR-99 family expression diverges physiological hypertrophy from pathological hypertrophy

The physiological cardiac hypertrophy is an adaptive condition without myocyte cell death, while pathological hypertrophy is a maladaptive condition associated with myocyte cell death. This study explores the miRNome of α-2M-induced physiologically hypertrophied cardiomyocytes and the role of miRNA-99 family during cardiac hypertrophy. Physiological and pathological cardiac hypertrophy was induced in H9c2 cardiomyoblast cell lines using α-2M and isoproterenol respectively. Total RNA isolation and small RNA sequencing were executed for physiological hypertrophy model. The differentially expressed miRNAs and its target mRNAs were validated in animal models. Transcription factor binding sites were predicted in the promoter of specific miRNAs and validated by ChIP-PCR. Subsequently, the selected miRNA was functionally characterized by overexpression and silencing. The effects of silencing of upstream regulator and downstream target gene were studied. Analysis of small RNA reads revealed the differential expression of a large set of miRNAs during hypertrophy, of which miR-99 family was highly downregulated upon α-2M treatment. However, this miR-99 family expression was upregulated during pathological hypertrophy and confirmed in animal models. ChIP-PCR confirms the binding of Egr-1 transcription factor to the miR-99 promoter. Further, silencing of Egr-1 decreased the expression of miR-99. The overexpression or silencing of miR-99 diverges the physiological hypertrophy to pathological hypertrophy and vice versa by regulating Akt-1 pathway. Silencing of Akt-1 replicates the effect of overexpression of miR-99.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Overexpression of miR-133 decrease primary endothelial cells proliferation and migration via FGFR1 targeting

Highlights: • FGFR1 signaling can bring about angiogenesis in cancer. • Through downregulating FGFR1, miR-133 caused reductions in bFGF activity. • Reduced bFGF activity result in diminished proliferation and migratory ability of ECs. • Overexpression of miR-133 could reduce the rate of cell division. • MiR-133 could disturb capillary network formation of transfected ECs as well. Angiogenesis is one of the essential hallmarks of cancer that is controlled by the balance between positive and negative regulators. FGFR1 signaling is crucial for the execution of bFGF-induced proliferation, migration, and tube formation of endothelial cells (ECs) and onset of angiogenesis on tumors. The purpose of this study is to identify whether or not miR-133 regulates FGFR1 expression and accordingly hypothesize if it plays a crucial role in modulating bFGF/FGFR1 activity in ECs and blocking tumor angiogenesis through targeting FGFR1. The influences of miR-133 overexpression on bFGF stimulated endothelial cells were assessed by cell growth curve, MTT assaying, tube formation, and migration assays. Forced expression of miR-133 caused significant reductions in bFGF-induced proliferation and migratory ability of ECs. MiR-133 Expression was negatively correlated with both mRNA and protein levels of FGFR1 in the transfected ECs isolated from peripheral blood. Moreover, overexpression of miR-133 drastically reduced the rate of cell division and disturbed capillary network formation of transfected ECs. These findings suggest that miR-133 plays an important function in bFGF-induced angiogenesis processes in ECs and provides a rationale for new therapeutic approaches to suppress tumor angiogenesis and cancer.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Mechano-growth factor protects against mechanical overload induced damage and promotes migration of growth plate chondrocytes through RhoA/YAP pathway

Highlights: • Cyclic mechanical stress induces MGF expression and MGF protects against mechanical overload induced apoptosis and inflammation. • MGF regulates YAP activation to induce chondrocytes migration via RhoA. • MGF promotes focal adhesion formation via RhoA-YAP pathway. Epiphyseal growth plate is highly dynamic tissue which is controlled by a variety of endocrine, paracrine hormones, and by complex local signaling loops and mechanical loading. Mechano growth factor (MGF), the splice variant of the IGF-I gene, has been discovered to play important roles in tissue growth and repair. However, the effect of MGF on the growth plate remains unclear. In the present study, we found that MGF mRNA expression of growth plate chondrocytes was upregulated in response to mechanical stimuli. Treatment of MGF had no effect on growth plate chondrocytes proliferation and differentiation. But it could inhibit growth plate chondrocytes apoptosis and inflammation under mechanical overload. Moreover, both wound healing and transwell assay indicated that MGF could significantly enhance growth plate chondrocytes migration which was accompanied with YAP activation and nucleus translocation. Knockdown of YAP with YAP siRNA suppressed migration induced by MGF, indicating the essential role of YAP in MGF promoting growth plate chondrocytes migration. Furthermore, MGF promoted YAP activation through RhoA GTPase mediated cytoskeleton reorganization, RhoA inhibition using C3 toxin abrogated MGF induced YAP activation. Importantly, we found that MGF promoted focal adhesion(FA) formation and knockdown of YAP with YAP siRNA partially suppressed the activation of FA kinase, implying that YAP is associated with FA formation. In conclusion, MGF is an autocrine growth factor which is regulated by mechanical stimuli. MGF could not only protect growth plate chondrocytes against damage by mechanical overload, but also promote migration through activation of RhoA/YAP signaling axis. Most importantly, our findings indicate that MGF promote cell migration through YAP mediated FA formation to determine the FA-cytoskeleton remodeling.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

The IRF9-SIRT1-P53 axis is involved in the growth of human acute myeloid leukemia

Highlights: • IRF9 expression is increased in human acute myeloid leukemia (AML). • IRF9 represses AML cell growth. • IRF9 induces AML cell apoptosis. • IRF9 inhibits the expression of SIRT1. • IRF9 promotes p53 deacetylation and regulates p53 target genes. Acute myeloid leukemia (AML) is a highly heterogeneous disease, with biologically and prognostically different subtypes. Although a growing number of distinct AML subsets have been increasingly characterized, patient management has remained disappointingly uniform. The molecular mechanism underlying AML needs to be further investigated. Here we identify IRF9 as a negative regulator of human AML. We show that IRF9 mRNA and protein levels are down-regulated in human AML samples compared with samples from healthy donors. IRF9 knockdown promotes proliferation, colony formation and survival of OCI/AML-2 and OCI/AML-3 cells, whereas IRF9 overexpression obtains oppose results. Mechanism analysis shows that IRF9 binds SIRT1 promoter and represses SIRT1 expression in OCI/AML-2 and OCI/AML-3 cells. In AML samples, the expression of SIRT1 is up-regulated and negatively correlated with IRF9 level. IRF9 also increases the acetylation of p53, a deacetylation substrate of SIRT1, and promotes the expression of p53 target genes. Knockdown of p53 blocks the effects of IRF9 on cell survival and growth in vitro. These findings provide evidence that IRF9 serves as an important regulator in human AML by repressing SIRT1-p53 pathway and that IRF9 may be a potential target for AML treatment.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

RNA helicase DDX5 participates in oxLDL-induced macrophage scavenger receptor 1 expression by suppressing mRNA degradation

Highlights: • RNA helicase DDX5 positively regulates macrophage lipid uptake. • Macrophages scavenger receptor 1(MSR1) mRNA is stabilized by DDX5. • The m{sup 6}a modification of MSR1 mRNA was regulated by interaction of mettl3 and DDX5. • Degradation of MSR1 mRNA was suppressed by m{sup 6}a modification on mRNA. The DEAD box protein DDX5, an ATP-dependent RNA helicase, plays an important role in transcriptional regulation and is associated with solid tumors and leukemia. However, its role in oxLDL-induced lipid uptake in macrophages remains unclear. In this study, we detected the expression of DDX5 mRNA and protein in oxidized low-density lipoprotein (oxLDL)-treated human primary macrophages that were induced from monocytes isolated from human peripheral blood with or without several chemical inhibitors using quantitative real-time PCR (qRT-PCR) or Western blotting. We found that oxLDL induced DDX5 expression to be independent of both the MAPK and NF-κB pathways. We also found that DDX5 promoted macrophage lipid uptake by evaluating the fluorescence intensity of engulfed dil-oxLDL. Various scavenger receptors that participate in lipid uptake were detected in siR-DDX5 transfected macrophages using qRT-PCR and Western blotting. Macrophage scavenger receptor A (MSR1) was found to be involved the upregulation of DDX5-mediated lipid uptake. Through the use of a dual luciferase reporter assay system and incubation with cycloheximide (CHX) MG132 and actidione (ActD), we found that DDX5 promoted MSR1 protein expression by stabilizing MSR1 mRNA. Moreover, the mechanism involved in DDX5 regulation of MSR1 mRNA was also explored using mass spectrum analysis; Immunoprecipitations (IPs) and RNA- Immunoprecipitations (R-IPs) revealed that mettl3 was involved in DDX5-mediated MSR1 mRNA stabilization. In addition, we also demonstrated that DDX5 inhibited mettl3 to catalyze m{sup 6}a methylation in MSR1 mRNA, which contributed to the maintenance of MSR1 mRNA stability. In conclusion, ox-LDL promotes DDX5 expression in macrophages, which interacts with mettl3 to stabilize MSR1 mRNA by decreasing the m{sup 6}a modification of MSR1 mRNA, ultimately promoting lipid uptake in macrophages.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Overexpression of miR-182 inhibits ossification of ligamentum flavum cells by targeting NAMPT

Ossification of the ligamentum flavum (OLF) is a debilitating disease resulting from the development of ectopic bone formation, which leads to the compression of the spinal cord. Nicotinamide phosphoribosyltransferase (NAMPT) was found to be upregulated and microRNA-182 (miR-182) was downregulated in OLF tissue. We investigated the effects of NAMPT and miR-182 expression in OLF cells and the influence on proteins associated with osteogenic differentiation. MiR-182 overexpression inhibited NAMPT, RUNX2, OCN and OPN mRNA and protein expression in OLF cells. Alkaline phosphatase (ALP) assay and Alizarin red staining confirmed reduced levels of osteogenic differentiation and mineralized nodule formation. Knockdown of NAMPT and the NAMPT inhibitor FK866 also inhibits RUNX2, OCN and OPN mRNA expression and protein levels, whereas overexpression of NAMPT promotes the expression of RUNX2, OCN and OPN and the generation of bone nodules. Dual-luciferase reporter assays revealed that miR-182 directly targets NAMPT and downregulates its expression. Transfection of OLF cells with miR-182 downregulated NAMPT and suppressed the regulation of RUNX2, OCN, and OPN by NAMPT overexpression. Overall, these data demonstrate that miR-182 suppresses OLF by downregulating NAMPT.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

MiR-155 targets PTCH1 to mediate endothelial progenitor cell dysfunction caused by high glucose

Highlights: • MiR-155 was upregulated in EPCs of patients with DFU. • High glucose–induced upregulation of miR-155 in EPCs. • MiR-155 exacerbated EPCs dysfunction induced by high glucose. • MiR-155 targeted PTCH1 in EPCs. • MiR-155 impaired EPCs function via PTCH1 suppression. Endothelial progenitor cells (EPCs) are involved in diabetes-associated complications, including diabetic foot ulcer (DFU). Recent reports showed that miR-155 downregulation promotes wound healing in diabetic rats and ameliorates endothelial injury induced by high glucose, but its role in DFU is unknown. We found that miR-155 was overexpressed in EPCs from patients with DFU and in high glucose–induced EPCs from healthy people. Reductions in cell viability, migration, tube formation and nitric oxide production, as well as increases in lactated hydrogenase, cell apoptosis, and reactive oxygen species induced by high glucose, were enhanced by miR-155 overexpression and restrained by miR-155 inhibition. Additionally, dual-luciferase reporter assay demonstrated that miR-155 directly targeted the 3′ untranslated region of patched-1 (PTCH1), a receptor of the sonic hedgehog signaling pathway, and downregulated the mRNA and protein expression of PTCH1. qRT-PCR and Western blot results revealed that the PTCH1 was downregulated in EPCs treated with high glucose. Silencing PTCH1 by PTCH1 siRNA alleviated the protective effect of anti-miR-155 on high glucose–induced EPC dysfunction. Our results indicate that miR-155 worsened high glucose–induced EPC function by downregulating PTCH1. These findings suggest that miR-155 may be a potential therapeutic target for DFU.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Chitosan oligosaccharides enhance lipid droplets via down-regulation of PCSK9 gene expression in HepG2 cells

Highlights: • COS enhance lipid droplets in HepG2 cells. • COS down-regulate the expression of PCSK9 to maintain hepatic LDLR abundance and activity. • COS inhibit HNF1α and SREBP-2 activity leading to down-regulation of PCSK9. Chitosan oligosaccharides (COS), linear polymers of N-acetyl-D-glucosamine and deacetylated glucosamine, exhibit diverse pharmacological effects such as antimicrobial, antitumor, antioxidant and anti-inflammatory activities. Here, we explored their hypocholesterolemic effects in vivo and the molecular mechanisms of COS in hepatic cells. Our in vivo study of dyslipidemic ApoE{sup -/-} male mice showed that COS treatment of 500 mg kg{sup −1} d{sup −1} for 4 weeks clearly reduced the lipid deposits in the aorta and significantly decreased the hepatic proprotein convertase subtilisin/kexin type 9 (PCSK9) protein levels versus HFD groups (p < 0.05). To elucidate the mechanisms behind these effects, the HepG2 cell line was treated with COS. We found that COS (200 μg/ml) increased the amount of cell-surface low-density lipoprotein receptor (LDLR) and enhanced the lipid droplets in HepG2 cells (p < 0.05). The mRNA levels of LDLR and HMG-CoA protein levels were not altered, and the mRNA levels of PCSK9 were down-regulated by COS treatment for 24 h. We also observed that the expression levels of SREBP-2 (125 kD) and HNF-1α were increased in total cell lysates, but nuclear SREBP-2 (nSREBP-2, 68 kD, the active subunit of SREBP-2) levels were decreased and FOXO3a levels increased in nuclear lysates after COS treatment for 24 h. We demonstrated that one of the reasons for regulation of lipid transfer with COS is that FOXO3a levels are up-regulated by COS, leading to a reduction in the PCSK9 promoter binding capacity of HNF-1α and thus suppressing PCSK9 gene expression, up-regulating LDLR levels, and enhancing the lipid droplets in HepG2 cells. In addition, decreased expression of the PCSK9 gene was also contributed to by down-regulation of SREBP-2 by COS. We further confirmed the effect of suppression of PCSK9 expression by COS by utilizing RNA interference to silence HNF-1α and SREBP-2. Finally, to the best of our knowledge, we are the first to demonstrate that PCSK9 expression and LDLR activity are synergistically changed by a combination of HNF-1α and SREBP-2 after COS treatment. Our findings indicate that COS may regulate PCSK9 to modulate hepatic LDLR abundance and activity.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Knockdown of MALAT1 enhances chemosensitivity of ovarian cancer cells to cisplatin through inhibiting the Notch1 signaling pathway

Highlights: • MALAT1 knockdown reversed CDDP resistance in CDDP-resistant ovarian cancer cells. • MALAT1 knockdown inhibits the Notch1 pathway and ABCC1 expression. • MALAT1 interacts with Notch1 in ovarian cancer cells. • Notch1 knockdown reverses CDDP resistance in CDDP-resistant ovarian cancer cells. • MALAT1 knockdown enhances cytotoxicity of CDDP in ovarian cancer cells in vivo. Long non-coding RNAs (lncRNAs) are critical regulators in chemoresistance of various tumors including ovarian cancer. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been reported to be upregulated and contributed to ovarian cancer tumorigenesis. The aim of this study was to explore the roles of MALAT1 and the underlying molecular regulatory mechanism in the chemoresistance of ovarian cancer cells. Our data demonstrated that MALAT1 and Notch1 mRNA were upregulated in ovarian cancer tissues, as well as cisplatin (CDDP)-resistant ovarian cancer cells. A positive correlation between MALAT1 and Notch1 mRNA expression was observed. MALAT1 knockdown significantly attenuated CDDP resistance, and enhanced CDDP-induced apoptosis in CDDP-resistant ovarian cancer cells. MALAT1 knockdown enhanced CDDP-induced apoptosis in vivo, as indicated by upregulation of Bax protein expression and downregulation of Bcl-2 protein expression. Additionally, MALAT1 knockdown inhibited the Notch1 pathway and ABCC1 expression in CDDP-resistant ovarian cancer cells. MALAT1 was demonstrated to interact with Notch1. Notch1 knockdown attenuated CDDP resistance, and downregulated the protein expression of ABCC1 in ovarian cancer cells. Taken together, our findings suggested that knockdown of MALAT-1 enhanced chemosensitivity of ovarian cancer cells to CDDP through inhibiting Notch1 signaling pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Leptin up-regulates microRNA-27a/b-3p level in hepatic stellate cells

Highlights: • Leptin up-regulates miR-27a/b-3p levels in hepatic stellate cells (HSCs). • Multiple signaling pathways mediate the effect of leptin on miR-27a/b-3p. • miR-27a/b-3p reduce SREBP1c and LXRα levels, and inhibit HSC activation. • miR-27a/b-3p involved in leptin-associated liver fibrosis. Obese patients, often accompanied by hyperleptinemia, are prone to liver fibrogenesis. Leptin is an adipocyte-derived hormone and plays a promotion role in liver fibrosis. Sterol regulatory element binding protein-1c (SREBP1c) exerts a crucial role in inhibiting hepatic stellate cell (HSC) activation, a key step in liver fibrogenesis. Our previous studies indicated that leptin inhibited SREBP1c expression, contributing to leptin-induced HSC activation and liver fibrosis. microRNAs (miR) have emerged as important layers of regulatory control and regulate gene expression, and are implicated in numerous diseases. The present study revealed leptin up-regulation of miR-27a/b-3p levels in HSCs in vitro and in vivo. Three signaling pathways were required for leptin regulation of miR-27a/b-3p levels. miR-27a/b-3p could reduce SREBP1c and liver x receptor α (LXRα) levels, increased α-smooth muscle actin (α-SMA, a marker for HSC activation) and α1(I)collagen levels in cultured HSCs. miR-27a/b-3p regulation of SREBP1c and LXRα were independent of 3′-untranslated region of SREBP1c and LXRα mRNA. In vivo experiments further demonstrated the miR-27a/b-3p involved in leptin-associated decrease in SREBP1 level in HSCs, HSC activation, and liver fibrosis. These data might have potential implications for our understanding of molecular mechanisms underlying leptin roles in liver fibrogenesis of obese patients with hyperleptinaemia.

60 APPLIED LIFE SCIENCES↗