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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 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Bmi-1 plays a critical role in the protection from acute tubular necrosis by mobilizing renal stem/progenitor cells

The regeneration of injured tubular cell occurs primarily from intrinsic renal stem/progenitor cells (RSCs) labeled with CD24 and CD133 after acute tubular necrosis (ATN). Bmi-1 plays a crucial role in regulating self-renewal, differentiation and aging of multiple adult stem cells and progenitor cells. Bmi-1 was rapidly elevated in the induction of adult kidney regeneration by renal injury. To determine whether Bmi-1 maintained mobilization of RSCs in the protection from ATN, glycerol-rhabdomyolysis-induced ATN were performed in wild type (WT) and Bmi-1-deficient (Bmi-1{sup −/−}) mice. Their ATN phenotypes were analyzed; CD24 and CD133 double positive (CD24{sup +}CD133{sup +}) cells were measured; and the levels of serum urea nitrogen (SUN) and serum creatinine (SCr) were detected. We found that CD24{sup +}CD133{sup +} RSCs were mobilized in WT ATN mice with the increased expression of Bmi-1; Bmi-1 deficiency led to increased tubular cast formation and necrosis, elevated levels of SUN and SCr, decreased tubular proliferation, and immobilized ratio of RSCs in ATN. These findings indicated that Bmi-1 played a critical role in the protection from ATN by maintaining mobilization of RSCs and would be a novel therapeutic target for preventing the progression of ATN.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Functional characterization of Brassica napus DNA topoisomerase Iα-1 and its effect on flowering time when expressed in Arabidopsis thaliana

Previous studies have shown that DNA topoisomerase Iα (AtTOP1α) has specific developmental functions during growth and development in Arabidopsis thaliana. However, little is known about the roles of DNA topoisomerases in the closely related and commercially important plant, rapeseed (Brassica napus). Here, the full-length BnTOP1α-1 coding sequence was cloned from the A2 subgenome of the Brassica napus inbred line L111. We determine that all BnTOP1α paralogs showed differing patterns of expression in different organs of L111, and that when expressed in tobacco leaves as a fusion protein with green fluorescent protein, BnTOP1α-1 localized to the nucleus. We further showed that ectopic expression of BnTOP1α-1 in the A. thaliana top1α-7 mutant fully complemented the early flowering phenotype of the mutant. Moreover, altered expression levels in top1α-7 seedlings of several key genes controlling flowering time were restored to wild type levels by ectopic expression of BnTOP1α-1. These results provide valuable insights into the roles of rapeseed DNA topoisomerases in flowering time, and provide a promising target for genetic manipulation of this commercially significant process in rapeseed. - Highlights: • BnTOP1α-1 was cloned from the A2 subgenome of Brassica napus inbred line L111. • BnTOP1α-1 rescued the early flowering phenotype of the Attop1α-7 mutant. • BnTOP1α-1 rescued the altered expression of flowering time genes in the Attop1α-mutant. • The functions of BnTOP1α-1 and AtTOP1α are likely conserved.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Netrin-1 promotes metastasis of gastric cancer by regulating YAP activity

Yes-associated protein (YAP) is a major downstream molecular of the Hippo pathway, which plays important role in cancer development. Netrin-1 conveys oncogenic activity in many types of malignant tumors. However, the downstream signaling of netrin-1 mediating its oncogenic effects in gastric cancer (GC) is not well defined. Here, we aim to investigate the role of netrin-1 in metastasis potential of GC by regulating YAP. In this study, we showed that netrin-1 inhibition significantly decreased migration and invasion abilities of GC cells, while netrin-1 overexpression effectively reversed this effect. We also demonstrated that netrin-1 upregulated YAP expression via its transmembrane receptor neogenin. Furthermore, our in vitro and in vivo results showed that the effect of netrin-1 on GC cells migration and invasion abilities was regulated by YAP. Collectively, our results defined netrin-1 as a positive regulator of malignant tumor metastasis in GC by activating the YAP signaling, with potential implications for new approaches to GC therapy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Glucagon-like peptide-1 contributes to increases ABCA1 expression by downregulating miR-758 to regulate cholesterol homeostasis

Abnormal regulation of lipid metabolism is associated with type 2 diabetes mellitus (T2DM). GLP-1 as a new treatment for T2DM, has unique effects in modulating cholesterol homeostasis. However, the mechanism of this effect is largely missing. The aim of this study was to determine the effects of GLP-1 on cholesterol-induced lipotoxicity in hepatocytes and examine the underlying mechanisms. The cell viability was determined, and caspase-3 was used to detect the effects of GLP-1 on cholesterol-induced apoptosis. The alterations of miR-758 and ATP-binding cassette transporter A1 (ABCA1) resulting from cholesterol incubation or GLP-1 were detected by qRT-PCR and Western blot assays. Overexpression of miR-758 abrogated the GLP-1-mediated ABCA1 expression, and conversely, down-regulation of miR-758 aggravated GLP-1's action and revealed significant promotion effects. BODIPY-Cholesterol efflux assay revealed that treatment with miR-758 inhibitor significantly enhanced ABCA1-dependent cholesterol efflux, resulting in reduced total cholesterol. Furthermore, Oil red O staining and cholesterol measurement were used to detect lipid accumulation. As a result, cholesterol significantly attenuated cell viability, promoted cell apoptosis, and facilitated lipid accumulation, and these effects were reversed by GLP-1. This study provides evidence that, in HepG2 cells, GLP-1 may affect cholesterol homeostasis by regulating the expression of miR-758 and ABCA1. These data can inform the development of biomarkers for miR-758, and potentially other drugs, on the key pathways of lipid metabolism.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

GLP-1 receptor agonist liraglutide exerts central action to induce β-cell proliferation through medulla to vagal pathway in mice

Highlights: • ICV injected GLP-1RA liraglutide and GLP-1 induce pancreatic β-cell proliferation. • This effect is induced by single shot liraglutide at low dose not touching feeding. • This effect is inhibited by atropine and hence possibly mediated by vagal efferent. • ICV liraglutide activates dorsal vagal complex (DVC), suggesting DVC-vagal reflex. • This pathway may serve to counteract β-cell reduction in diabetic patients. Endogenous GLP-1 and GLP-1 receptor agonists (GLP-1RAs) regulate glucose metabolism via common and distinct mechanisms. Postprandial release of GLP-1 is modest and it is degraded by DPP-4 within 2 min, and hence it cannot enter the brain in substantial amount. In contrast, DPP-4-resistant GLP-1RAs are administered at 10 times higher concentration than endogenous GLP-1 level, which enables them to reach several brain regions including ARC and AP, the areas implicated in glucose metabolism. Hence, some of the effects of GLP-1RAs observed clinically and experimentally, including pancreatic β-cell proliferation, are thought to involve the brain. However, the effects of centrally acting GLP-1/GLP-1RAs on glucose metabolism and underlying neural mechanism are unclear. This study aimed to establish the link of central GLP-1/GLP-1RA action to pancreatic β-cell proliferation. Both subcutaneous (SC) and intracerebroventricular (ICV) injections of liraglutide increased the number of pancreatic β-cells expressing Ki67 and PCNA, proliferation markers, in C57BL/6J mice. This effect was induced by single ICV administration of liraglutide at relatively low dose that was incapable of suppressing food intake. These SC and ICV liraglutide-induced effects were inhibited by 50% and 70%, respectively, by pretreatment with atropine, a muscarinic receptor blocker. ICV liraglutide induced c-Fos expression in the area postrema (AP), nucleus tractus solitaries (NTS), and dorsal motor nucleus of the vagus (DMX) of the brain stem. These results demonstrate that central action of liraglutide induces pancreatic β-cell proliferation via the pathway involving the brain stem AP/NTS/DMX area and vagus nerve. This route is highly sensitive to GLP-1/GLP-1RA. Hence, this brain-pancreatic β-cell pathway may operate in type 2 diabetic patients treated with GLP-RAs and serve to counteract the reduction of β-cell mass.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

IGF-1 resist oxidative damage to HaCaT and depigmentation in mice treated with H2O2

Vitiligo, an acquired pigmentary disorder of the skin, is characterized by a chronic and progressive loss of melanocyte from the epidermis and follicular reservoir. Growth factor of surrounding cells impacted on melanocytes survival. In this study, lower level of IGF-1 in the lesion was found than that in the donor area of vitiligo patients. IGF-1 improved activation of Nrf2, and inhibited ROS generation and endoplasmic reticulum dilation in HaCaT. C57BL/6 mice were treated with 5% H{sub 2}O{sub 2}, and combined with 50 μg/kg of IGF-1 pre-treatment or not once every day for 50 consecutive days. After 50 days, IGF-1 obviously ameliorated depigmentation of mice skin and reduced hair follicle length, skin thickness and Tyrosinase induced by H{sub 2}O{sub 2.} Moreover, IGF-1 significantly suppressed CD8{sup +} T cells infiltration in mice skin, inhibited the production of IL-2 and IFN-γ, and decreased the expression of CXCL10 and CXCR3. Thus, the results indicated that IGF-1 could resist oxidative damage to HaCaT, suppress CD8{sup +} T cells infiltration and pro-inflammatory cytokines secretion, and suppresses the thinning of epidermal layer in vivo. It suggests that IGF-1 inhibits oxidative damage to HaCaT and immunosuppressive effects on CD8{sup +} T cells proliferation and activation to resist depigmentation induced by H{sub 2}O{sub 2}. This disclosed its multiple roles in the vitiligo, and shed a light on developing the application potential for IGF-1 in vitiligo.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Mercury-induced vascular dysfunction is mediated by angiotensin II AT-1 receptor upregulation

Highlights: • Chronic exposure to Hg promotes Ang II AT-1 receptors upregulation in aorta. • Ang II AT-1 receptors activation induces vascular damage in rats exposed to Hg. • Upregulation of Ang II AT-1 receptors by Hg increases ROS and prostanoids levels. • Oxidative stress caused by Ang II AT-1 receptors activation reduces NO bioavailability. Low doses of mercury (Hg) promote deleterious effects on cardiovascular system, but the mechanisms implicated remain unclear. This study analyzed whether angiotensin II AT-1 receptors are involved in the vascular dysfunction caused by chronic exposure to low HgCl{sub 2} doses. For this, rats were divided into four groups and untreated (saline by im injections and tap water by gavage) or treated for 30 days as follows: Mercury (HgCl{sub 2} im, first dose of 4.6 µg kg{sup −1} and subsequent doses of 0.07 µg kg{sup −1} day{sup −1}, and tap water by gavage); Losartan (saline im and losartan, 15 mg kg{sup −1} day{sup −1}, by gavage); Losartan-Mercury (HgCl{sub 2} im and Losartan by gavage). Systolic blood pressure was measured by tail plethysmography, vascular reactivity in aorta by isolated organ bath, oxidative stress by measuring the levels of reactive oxygen species (ROS), malondialdehyde (MDA) and antioxidant capacity (FRAP) and protein expression of AT-1 receptors by Western Blot. As results, co-treatment with losartan prevented the increased aortic vasoconstrictor responses to phenylephrine (Phe), the involvement of ROS and prostanoids on the response to Phe and the reduced negative endothelial modulation by nitric oxide on these responses. Moreover, this co-treatment avoided the increase in plasmatic and vascular oxidative stress and AT-1 protein expression in aorta. In conclusion, these results suggest that AT-1 receptors upregulation might play a key role in the vascular damage induced by Hg exposure by increasing oxidative stress and probably by reducing NO bioavailability.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Castration Therapy of Prostate Cancer Results in Downregulation of HIF-1{alpha} Levels

Background and Purpose: Neoadjuvant androgen deprivation in combination with radiotherapy of prostate cancer is used to improve radioresponsiveness and local tumor control. Currently, the underlying mechanism is not well understood. Because hypoxia causes resistance to radiotherapy, we wanted to test whether castration affects the degree of hypoxia in prostate cancer. Methods and Materials: In 14 patients with locally advanced prostate cancer, six to 12 prostatic needle core biopsy specimens were taken prior to castration therapy. Bilateral orchidectomy was performed in 7 patients, and 7 were treated with a GnRH-agonist (leuprorelin). After castrationm two to four prostatic core biopsy specimens were taken, and the level of hypoxia-inducible factor-1{alpha} (HIF-1{alpha}) in cancer was determined by immunofluorescence. Results: Among biopsy specimens taken before castration, strong HIF-1{alpha} expression (mean intensity above 30) was shown in 5 patients, weak expression (mean intensity 10-30) in 3 patients, and background levels of HIF-1{alpha} (mean intensity 0-10) in 6 patients. Downregulation of HIF-1{alpha} expression after castration was observed in all 5 patients with strong HIF-1{alpha} precastration expression. HIF-1{alpha} expression was also reduced in 2 of 3 patients with weak HIF-1{alpha} precastration expression. Conclusions: Our data suggest that neoadjuvant castration decreases tumor cell hypoxia in prostate cancer, which may explain increased radiosensitivity after castration.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Intercellular Adhesion Molecule-1 and Vascular Cell Adhesion Molecule Are Induced by Ionizing Radiation on Lymphatic Endothelium

Purpose/Objectives: The goal of this study was to assess the effects of ionizing radiation on the expression of the integrin ligands ICAM-1 and VCAM that control leucocyte transit by lymphatic endothelial cells. Materials/Methods: Confluent monolayers of primary human lymphatic endothelial cells (LEC) were irradiated with single dose of 2, 5, 10 or 20 Gy, with 6 MeV-x-rays using a Linear-Accelerator. ICAM-1 and VCAM expression was determined by flow cytometry. Human tissue specimens received a single dose of 20 Gy with 15 MeV-x-rays. MC38, B16-OVA or B16-VEGF-C tumors grown in C57BL/6 mice were irradiated with single dose of 20Gy using a Linear-Accelerator fitted with a 10mm Radiosurgery collimator. Clinical samples were obtained from patients previous and 4 weeks after complete standard radiotherapy. ICAM-1 and VCAM expression was detected in all tissue specimens by confocal microscopy. To understand the role of TGFβ in this process anti-TGFβ blocking mAb were injected i.p. 30min before radiotherapy. Cell adhesion to irradiated LEC was analyzed in adhesion experiments performed in the presence or in the absence of anti- TGFβ and /or anti-ICAM1 blocking mAb. Results: We demonstrate that lymphatic endothelial cells in tumor samples experience induction of surface ICAM-1 and VCAM when exposed to ionizing radiation in a dose- and time-dependent manner. These effects can be recapitulated in cultured LEC, and are in part mediated by TGFβ. These data are consistent with increases in ICAM-1 and VCAM expression on LYVE-1+ endothelial cells in freshly explanted human tumor tissue and in mouse transplanted tumors after radiotherapy. Finally, ICAM-1 and VCAM expression accounts for enhanced adherence of human T lymphocytes to irradiated LEC. Conclusion: Our results show induction of ICAM-1 and VCAM on LVs in irradiated lesions and offer a starting point for elucidating the biological and therapeutic implications of targeting leukocyte traffic in combination to immunotherapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Hydrothermal synthesis of hierarchical titanium silicalite-1 using single template

Graphical abstract: . Hierarchical nano-crystalline TS-1 can be simply synthesized using tetrapropylammonium hydroxide as single template in presence of a 'seed' gel. Research highlights: {yields} Hierarchical nano-crystalline TS-1 can be directly synthesized using tetrapropylammonium hydroxide (TPAOH) as single template in presence of a 'seed' gel. The presence of seed favored the aggregation of TS-1 nanoparticles and thus lead to the interstitial voids that contributed to secondary mesoporosity. The presence of seed could accelerate the crystallization rate and reduce the amount of template, TPAOH. -- Abstract: Hierarchical nano-crystalline TS-1 can be directly synthesized using tetrapropylammonium hydroxide (TPAOH) as single template in the presence of a 'seed' gel. The hierarchical nano-crystalline TS-1 was characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, UV-Vis diffuse reflectance spectroscopy and nitrogen adsorption-desoprtion. Compared with the conventional TS-1, the hierarchical nano-crystalline TS-1 contained an additional porosity including supermicro/mesopores, which attributed to the interstitial voids existing between the nanocrystals. The secondary porosity in the TS-1 material provided an enhanced external surface area and high mesopore volume in favor of fast diffusion of both reactants and products, which resulted in an enhanced activity in the epoxidation of bulky molecules cyclohexene using aqueous H{sub 2}O{sub 2} solution as oxidant.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Oleanolic acid supplement attenuates liquid fructose-induced adipose tissue insulin resistance through the insulin receptor substrate-1/phosphatidylinositol 3-kinase/Akt signaling pathway in rats

Oleanolic acid, a triterpenoid contained in more than 1620 plants including various fruits and foodstuffs, has numerous metabolic effects, such as hepatoprotection. However, its underlying mechanisms remain poorly understood. Adipose tissue insulin resistance (Adipo-IR) may contribute to the development and progress of metabolic abnormalities through release of excessive free fatty acids from adipose tissue. This study investigated the effect of oleanolic acid on Adipo-IR. The results showed that supplement with oleanolic acid (25 mg/kg, once daily, by oral gavage) over 10 weeks attenuated liquid fructose-induced increase in plasma insulin concentration and the homeostasis model assessment of insulin resistance (HOMA-IR) index in rats. Simultaneously, oleanolic acid reversed the increase in the Adipo-IR index and plasma non-esterified fatty acid concentrations during the oral glucose tolerance test assessment. In white adipose tissue, oleanolic acid enhanced mRNA expression of the genes encoding insulin receptor, insulin receptor substrate (IRS)-1 and phosphatidylinositol 3-kinase. At the protein level, oleanolic acid upregulated total IRS-1 expression, suppressed the increased phosphorylated IRS-1 at serine-307, and restored the increased phosphorylated IRS-1 to total IRS-1 ratio. In contrast, phosphorylated Akt to total Akt ratio was increased. Furthermore, oleanolic acid reversed fructose-induced decrease in phosphorylated-Akt/Akt protein to plasma insulin concentration ratio. However, oleanolic acid did not affect IRS-2 mRNA expression. Therefore, these results suggest that oleanolic acid supplement ameliorates fructose-induced Adipo-IR in rats via the IRS-1/phosphatidylinositol 3-kinase/Akt pathway. Our findings may provide new insights into the mechanisms of metabolic actions of oleanolic acid. - Highlights: • Adipose insulin resistance (Adipo-IR) contributes to metabolic abnormalities. • We investigated the effect of oleanolic acid (OA) on adipo-IR in fructose-fed rats. • OA attenuated fructose-induced increase in Adipo-IR index and NEFA concentrations. • OA modulated adipose IRS-1/phosphatidylinositol 3-kinase/Akt signaling. • OA ameliorates Adipo-IR via the IRS-1/PI3K/Akt signaling pathway in rats.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Kaposi's-sarcoma-associated-herpesvirus-activated dendritic cells promote HIV-1 trans-infection and suppress CD4{sup +} T cell proliferation

Infection of Kaposi's sarcoma-associated herpesvirus (KSHV) is commonly occurred in AIDS patients. KSHV and HIV-1 act cooperatively in regulating infection with each other and in human carcinogenesis. Dendritic cells (DCs), as the pivotal cells in host immunity, may be modulated by both viruses, for immunoevasion and dissemination, therefore, the interaction between DCs and each virus has been a prior focus for pathogenesis elucidation. Here, we assessed the potential effect of KSHV on DC–HIV-1 interaction. We found that KSHV stimulation could promote maturation of monocyte-derived DCs (MDDCs) and impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells, demonstrating the immunosuppression induced by KSHV. More importantly, KSHV-stimulated MDDCs could capture more HIV-1 and efficiently transferred these infectious viruses to Hut/CCR5 T cell line. Our results reveal the novel modulation of DC-mediated HIV-1 dissemination by KSHV, and highlight the importance of studying DC–HIV-1 interaction to elucidate HIV/AIDS pathogenesis. - Highlights: ► KSHV impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells. ► KSHV stimulation matured MDDCs and enhanced HIV-1 endocytosis. ► KSHV stimulated MDDCs increased ICAM-1 expression and tighten contact with T cells. ► KSHV-stimulated MDDCs promoted HIV-1 trans-infection of CD4{sup +} T cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Acetylation of the c-MYC oncoprotein is required for cooperation with the HTLV-1 p30{sup II} accessory protein and the induction of oncogenic cellular transformation by p30{sup II}/c-MYC

The human T-cell leukemia retrovirus type-1 (HTLV-1) p30{sup II} protein is a multifunctional latency-maintenance factor that negatively regulates viral gene expression and deregulates host signaling pathways involved in aberrant T-cell growth and proliferation. We have previously demonstrated that p30{sup II} interacts with the c-MYC oncoprotein and enhances c-MYC-dependent transcriptional and oncogenic functions. However, the molecular and biochemical events that mediate the cooperation between p30{sup II} and c-MYC remain to be completely understood. Herein we demonstrate that p30{sup II} induces lysine-acetylation of the c-MYC oncoprotein. Acetylation-defective c-MYC Lys→Arg substitution mutants are impaired for oncogenic transformation with p30{sup II} in c-myc{sup −/−} HO15.19 fibroblasts. Using dual-chromatin-immunoprecipitations (dual-ChIPs), we further demonstrate that p30{sup II} is present in c-MYC-containing nucleoprotein complexes in HTLV-1-transformed HuT-102 T-lymphocytes. Moreover, p30{sup II} inhibits apoptosis in proliferating cells expressing c-MYC under conditions of genotoxic stress. These findings suggest that c-MYC-acetylation is required for the cooperation between p30{sup II}/c-MYC which could promote proviral replication and contribute to HTLV-1-induced carcinogenesis. - Highlights: • Acetylation of c-MYC is required for oncogenic transformation by HTLV-1 p30{sup II}/c-MYC. • Acetylation-defective c-MYC mutants are impaired for foci-formation by p30{sup II}/c-MYC. • The HTLV-1 p30{sup II} protein induces lysine-acetylation of c-MYC. • p30{sup II} is present in c-MYC nucleoprotein complexes in HTLV-1-transformed T-cells. • HTLV-1 p30{sup II} inhibits apoptosis in c-MYC-expressing proliferating cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Involvement of IGF-1 and MEOX2 in PI3K/Akt1/2 and ERK1/2 pathways mediated proliferation and differentiation of perivascular adipocytes

Perivascular adipocyte (PVAC) proliferation and differentiation were closely involved in cardiovascular disease. We aimed to investigate whether phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways enhance PVAC functions activated by insulin-like growth factor 1(IGF-1) and suppressed by mesenchyme homeobox 2 (MEOX2). In this study, PVACs from primary culture were cultured and induced to differentiate. Cell viability assays demonstrated that IGF-1 promoted PVAC proliferation and differentiation. However MEOX2 counteracted these IGF-1-mediated actions. Flow Cytometry revealed that IGF-1 increased S phase cells and decreased apoptosis; however, MEOX2 decreased S phase cells, increased G0–G1 phase cells, and promoted apoptosis. During PVAC proliferation and differentiation, IGF-1 activated PI3K/Akt1/2 and ERK1/2 signaling pathways, upregulated the expression of these signaling proteins and FAS, and increased PVAC lipid content. In contrast, MEOX2 constrained the phosphorylation of ERK1/2 and Akt1/2 protein, down-regulated these signaling molecules and FAS, and decreased PVAC lipid content. Instead, MEOX2 knockdown enhanced the ERK1/2 and Akt1/2 phosphorylation, augmented the expression of these signaling molecules and FAS, and increased PVAC lipid content. Our findings suggested that PI3K/Akt1/2 and ERK1/2 activation mediated by IGF-1 is essential for PVAC proliferation and differentiation, and MEOX2 is a promising therapeutic gene to intervene in the signaling pathways and inhibit PVAC functions. - Highlights: • IGF-1 activated PI3K/Akt2 and ERK1/2 pathways to mediate PVAC proliferation and differentiation. • The expression of ERK1, ERK 2, PI3K, Akt1 and Akt2 showed different change trends between PVAC proliferation and differentiation. • MEOX2 effectively expressed in PVAC, increased early and late cellular apoptosis, and inhibited its proliferation. • MEOX2 depressed PVAC differentiation and FAS expression, and decreased lipid content in PVAC. • MEOX2 repressed the effects of IGF-1 on PVAC by restraining the activation of PI3K/Akt1/2 and ERK1/2 signaling pathways.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Claudin-1 promotes TNF-α-induced epithelial-mesenchymal transition and migration in colorectal adenocarcinoma cells

Epithelial-mesenchymal transition (EMT) is an important mechanism in cancer progression and malignancy including colorectal cancer (CRC). Importantly, inflammatory mediators are critical constituents of the local tumor environment and an intimate link between CRC progression and inflammation is now validated. We and others have reported key role of the deregulated claudin-1 expression in colon carcinogenesis including colitis-associated colon cancer (CAC). However, the causal association between claudin-1 expression and inflammation-induced colon cancer progression remains unclear. Here we demonstrate, TNF-α, a pro-inflammatory cytokine, regulates claudin-1 to modulate epithelial to mesenchymal transition (EMT) and migration in colon adenocarcinoma cells. Importantly, colon cancer cells cultured in the presence of TNF-α (10 ng/ml), demonstrated a sharp decrease in E-cadherin expression and an increase in vimentin expression (versus control cells). Interestingly, TNF-α treatment also upregulated (and delocalized) claudin-1 expression in a time-dependent manner accompanied by increase in proliferation and wound healing. Furthermore, similar to our previous observation that claudin-1 overexpression in CRC cells induces ERK1/2 and Src- activation, signaling associated with colon cancer cell survival and transformation, TNF-α-treatment induced upregulation of phospho-ERK1/2 and -Src expression. The shRNA-mediated inhibition of claudin-1 expression largely abrogated the TNF-α-induced changes in EMT, proliferation, migration, p-Erk and p-Src expression. Taken together, our data demonstrate TNF-α mediated regulation of claudin-1 and tumorigenic abilities of colon cancer cells and highlights a key role of deregulated claudin-1 expression in inflammation-induced colorectal cancer growth and progression, through the regulation of the ERK and Src-signaling.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Monocyte-lymphocyte fusion induced by the HIV-1 envelope generates functional heterokaryons with an activated monocyte-like phenotype

Enveloped viruses induce cell-cell fusion when infected cells expressing viral envelope proteins interact with target cells, or through the contact of cell-free viral particles with adjoining target cells. CD4{sup +} T lymphocytes and cells from the monocyte-macrophage lineage express receptors for HIV envelope protein. We have previously reported that lymphoid Jurkat T cells expressing the HIV-1 envelope protein (Env) can fuse with THP-1 monocytic cells, forming heterokaryons with a predominantly myeloid phenotype. This study shows that the expression of monocytic markers in heterokaryons is stable, whereas the expression of lymphoid markers is mostly lost. Like THP-1 cells, heterokaryons exhibited FcγR-dependent phagocytic activity and showed an enhanced expression of the activation marker ICAM-1 upon stimulation with PMA. In addition, heterokaryons showed morphological changes compatible with maturation, and high expression of the differentiation marker CD11b in the absence of differentiation-inducing agents. No morphological change nor increase in CD11b expression were observed when an HIV-fusion inhibitor blocked fusion, or when THP-1 cells were cocultured with Jurkat cells expressing a non-fusogenic Env protein, showing that differentiation was not induced merely by cell-cell interaction but required cell-cell fusion. Inhibition of TLR2/TLR4 signaling by a TIRAP inhibitor greatly reduced the expression of CD11b in heterokaryons. Thus, lymphocyte-monocyte heterokaryons induced by HIV-1 Env are stable and functional, and fusion prompts a phenotype characteristic of activated monocytes via intracellular TLR2/TLR4 signaling. - Highlights: • Jurkat T cells expressing the HIV-1 envelope fuse with THP-1 monocytes. • Heterokaryons display a dominant myeloid phenotype and monocyte function. • Heterokaryons exhibit activation features in the absence of activation agents. • Activation is not due to cell-cell interaction but requires cell-cell fusion. • The activated monocyte-like phenotype is mediated by TLR2/TLR4 signaling.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Heme oxygenase-1 protects bone marrow mesenchymal stem cells from iron overload through decreasing reactive oxygen species and promoting IL-10 generation

Iron overload (IO) caused by frequent blood transfusion in hematological diseases has become a major concern. In this study, up-regulation of heme oxygenase-1 (HO-1), a protector against oxidative stress, was observed in bone marrow mesenchymal stem cells (BMMSCs) at the early stage of IO and had favorable prognosis in an IO mouse model. Given that the protective role of HO-1 in IO damage of BMMSCs was still unknown, the mechanism was explored in vitro and in vivo. BMMSCs were transfected with HO-1/siHO-1 in vitro, and the mouse model was established to further evaluate the effect of HO-1 on IO in vivo. As a result, HO-1 decreased the apoptotic rate of BMMSCs with IO through reducing intracellular reactive oxygen species (ROS) but increasing IL-10 secretion. In addition, IL-10 was mediated by HO-1 via the ERK pathway. Intracellular iron was down-regulated by hepcidin depending on IL-10. In conclusion, HO-1 protects BMMSCs from ROS by secreting IL-10 upon iron overload.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Discovery of 2-Indole-acylsulfonamide Myeloid Cell Leukemia 1 (Mcl-1) Inhibitors Using Fragment-Based Methods

Myeloid cell leukemia-1 (Mcl-1) is a member of the Bcl-2 family of proteins responsible for the regulation of programmed cell death. Amplification of Mcl-1 is a common genetic aberration in human cancer whose overexpression contributes to the evasion of apoptosis and is one of the major resistance mechanisms for many chemotherapies. Mcl-1 mediates its effects primarily through interactions with pro-apoptotic BH3 containing proteins that achieve high affinity for the target by utilizing four hydrophobic pockets in its binding groove. Here we describe the discovery of Mcl-1 inhibitors using fragment-based methods and structure-based design. These novel inhibitors exhibit low nanomolar binding affinities to Mcl-1 and >500-fold selectivity over Bcl-xL. Additionally, X-ray structures of lead Mcl-1 inhibitors when complexed to Mcl-1 provided detailed information on how these small-molecules bind to the target and were used extensively to guide compound optimization.

60 APPLIED LIFE SCIENCES↗