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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Apparatus and method for measuring single cell and sub-cellular photosynthetic efficiency

Devices for measuring single cell changes in photosynthetic efficiency in algal aquaculture are disclosed that include a combination of modulated LED trans-illumination of different intensities with synchronized through objective laser illumination and confocal detection. Synchronization and intensity modulation of a dual illumination scheme were provided using a custom microcontroller for a laser beam block and constant current LED driver. Therefore, single whole cell photosynthetic efficiency, and subcellular (diffraction limited) photosynthetic efficiency measurement modes are permitted. Wide field rapid light scanning actinic illumination is provided for both by an intensity modulated 470 nm LED. For the whole cell photosynthetic efficiency measurement, the same LED provides saturating pulses for generating photosynthetic induction curves. For the subcellular photosynthetic efficiency measurement, a switched through objective 488 nm laser provides saturating pulses for generating photosynthetic induction curves. A second near IR LED is employed to generate dark adapted states in the system under study.

42 ENGINEERING↗
DOE OSTI2016

Particle control near reticle and optics using showerhead

A method and an apparatus to protect a reticle against particles and chemicals in an actinic EUV reticle inspection tool are presented. The method and apparatus utilizes a pair of porous metal diffusers in the form of showerheads to provide a continual flow of clean gas. The main showerhead bathes the reticle surface to be inspected in smoothly flowing, low pressure gas, isolating it from particles coming from surrounding volumes. The secondary showerhead faces away from the reticle and toward the EUV illumination and projection optics, supplying them with purge gas while at the same time creating a buffer zone that is kept free of any particle contamination originating from those optics.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Plant phenometrics systems and methods and devices related thereto

Chlorophyll fluorescence may be studied in response to a variety of environmental cues or conditions by growing phototrophic organisms under actinic illumination. Such illumination may be punctuated or disrupted to gain information about the photosynthetic properties or performance of the phototrophic organism. Instruments or devices for carrying out the method are also described.

47 OTHER INSTRUMENTATION↗
DOE OSTI2013

Photoheterotrophic growth of Physcomitrella patens

Physcomitrella patens is a model bryophyte representing an early land plant in the green plant lineage. This organism possesses many advantages as a model organism. Its genome has been sequenced, its predominant life cycle stage is the haploid gametophyte, it is readily transformable and it can integrate transformed DNA into its genome by homologous recombination. One limitation for the use of P. patens in photosynthesis research is its reported inability to grow photoheterotrophically, in the presence of sucrose and the Photosystem II inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea, which prevents linear photosynthetic electron transport. In this communication we describe the facile isolation of a P. patens strain which can grow photoheterotrophically. Additionally, we have examined a number of photosynthetic parameters for this strain grown under photoautotrophic, mixotrophic (in the presence of sucrose) and photoheterotrophic conditions, as well as the 3-(3,4-dichlorophenyl)-1,1-dimethylurea-inhibited state. In conclusion, the ability to grow P. patens photoheterotrophically should significantly facilitate its use in photosynthetic studies.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2014

Annexin A7 deficiency potentiates cardiac NFAT activity promoting hypertrophic signaling

Highlights: • Cardiac Anxa7 expression was up-regulated following TAC. • The hypertrophic response following TAC was augmented in Anxa7-deficient mice. • Silencing of Anxa7 increased indicators of HL-1 cardiomyocytes hypertrophy. • Silencing of Anxa7 induced Nfatc1 nuclear translocation. • Silencing of Anxa7 enhanced NFAT-dependent transcriptional activity. - Abstract: Annexin A7 (Anxa7) is a cytoskeletal protein interacting with Ca{sup 2+} signaling which in turn is a crucial factor for cardiac remodeling following cardiac injury. The present study explored whether Anxa7 participates in the regulation of cardiac stress signaling. To this end, mice lacking functional Anxa7 (anxa7{sup −/−}) and wild-type mice (anxa7{sup +/+}) were investigated following pressure overload by transverse aortic constriction (TAC). In addition, HL-1 cardiomyocytes were silenced with Anxa7 siRNA and treated with isoproterenol. Transcript levels were determined by quantitative RT-PCR, transcriptional activity by luciferase reporter assay and protein abundance by Western blotting and confocal microscopy. As a result, TAC treatment increased the mRNA and protein levels of Anxa7 in wild-type mice. Moreover, TAC increased heart weight to body weight ratio and the cardiac mRNA levels of αSka, Nppb, Col1a1, Col3a1 and Rcan1, effects more pronounced in anxa7{sup −/−} mice than in anxa7{sup +/+} mice. Silencing of Anxa7 in HL-1 cardiomyocytes significantly increased nuclear localization of Nfatc1. Furthermore, Anxa7 silencing increased NFAT-dependent transcriptional activity as well as αSka, Nppb, and Rcan1 mRNA levels both, under control conditions and following β-adrenergic stimulation by isoproterenol. These observations point to an important role of annexin A7 in the regulation of cardiac NFAT activity and hypertrophic response following cardiac stress conditions.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Sub-cellular force microscopy in single normal and cancer cells

This work investigates the biomechanical properties of sub-cellular structures of breast cells using atomic force microscopy (AFM). The cells are modeled as a triple-layered structure where the Generalized Maxwell model is applied to experimental data from AFM stress-relaxation tests to extract the elastic modulus, the apparent viscosity, and the relaxation time of sub-cellular structures. The triple-layered modeling results allow for determination and comparison of the biomechanical properties of the three major sub-cellular structures between normal and cancerous cells: the up plasma membrane/actin cortex, the mid cytoplasm/nucleus, and the low nuclear/integrin sub-domains. The results reveal that the sub-domains become stiffer and significantly more viscous with depth, regardless of cell type. In addition, there is a decreasing trend in the average elastic modulus and apparent viscosity of the all corresponding sub-cellular structures from normal to cancerous cells, which becomes most remarkable in the deeper sub-domain. The presented modeling in this work constitutes a unique AFM-based experimental framework to study the biomechanics of sub-cellular structures. - Highlights: • The cells are modeled as a triple-layered structure using Generalized Maxwell model. • The sub-domains include membrane/cortex, cytoplasm/nucleus, and nuclear/integrin. • Biomechanics of corresponding sub-domains are compared among normal and cancer cells. • Viscoelasticity of sub-domains show a decreasing trend from normal to cancer cells. • The decreasing trend becomes most significant in the deeper sub-domain.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Human fibrocyte-derived exosomes accelerate wound healing in genetically diabetic mice

Diabetic ulcers represent a substantial societal and healthcare burden worldwide and scarcely respond to current treatment strategies. This study was addressed to evaluate the therapeutic potential of exosomes secreted by human circulating fibrocytes, a population of mesenchymal progenitors involved in normal wound healing via paracrine signaling. The exosomes released from cells sequentially stimulated with platelet-derived growth factor-BB and transforming growth factor-β1, in the presence of fibroblast growth factor 2, did not show potential immunogenicity. These exosomes exhibited in-vitro proangiogenic properties, activated diabetic dermal fibroblasts, induced the migration and proliferation of diabetic keratinocytes, and accelerated wound closure in diabetic mice in vivo. Important components of the exosomal cargo were heat shock protein-90α, total and activated signal transducer and activator of transcription 3, proangiogenic (miR-126, miR-130a, miR-132) and anti-inflammatory (miR124a, miR-125b) microRNAs, and a microRNA regulating collagen deposition (miR-21). This proof-of-concept study demonstrates the feasibility of the use of fibrocytes-derived exosomes for the treatment of diabetic ulcers. - Highlights: • Fibrocytes have shown potent wound healing properties in vitro and in vivo. • Their clinical use is precluded by low numbers and antigen-presenting function. • We isolated exosomes with no immunogenicity potential from human fibrocytes. • Their cargo included microRNAs and proteins that are known healing promoters. • They accelerated wound closure in diabetic mice in a dose-dependent manner.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Effect of acid-sensing ion channel 1a on the process of liver fibrosis under hyperglycemia

Metabolic syndrome characterized by hyperglycemia contributes to nonalcoholic steatohepatitis-associated liver fibrosis. This study was to investigate the effects of Acid-sensing ion Channel 1a (ASIC1a) on the process of liver fibrosis under hyperglycemia. Results showed that high glucose significantly worsen the pathology of liver fibrosis in vivo. In vitro, high glucose stimulated proliferation, activation and extracellular matrix (ECM) production in HSCs, and enhanced the effect of PDGF-BB on the activation and proliferation of HSCs. These effects could be attenuated by ASIC1a specific inhibitor Psalmotoxin-1(PcTx1) or specific ShRNA for ASIC1a through Notch1/Hes-1 pathways. These data indicate that ASIC1a plays an important role in diabetes complication liver fibrosis. - Highlights: • Hyperglycemia is a risk factor for the process of liver fibrosis. • ASIC1a may be a key factor linking between high glucose and liver fibrosis. • Notch1/Hes-1 may involve to the process of liver fibrosis under hyperglycemia.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Evaluation of synthetic promoters in Physcomitrella patens

Highlights: • Cis-elements can be randomly assembled to construct short plant promoters. • Synthetic promoters have higher mRNA expression level than the endogenous PpAct7. • Synthetic promoters have similar protein expression levels to AtUBQ10 promoter. Securing a molecular toolbox including diverse promoters is essential for genome engineering. However, native promoters have limitations such as the available number or the length of the promoter. In this work, three short synthetic promoters were characterized by using the yellow fluorescent protein Venus. All of the tested promoters were active and showed higher mRNA expression than housekeeping gene PpAct7, and similar protein expression level to the AtUBQ10 promoter. This study shows that few cis-regulatory elements are enough to establish a strong promoter for continuous expression of genes in plants. Along with this, the study enhance the number of available promotors to be used in P. patens. It also demonstrates the potential to construct multiple non-native promoters on demand, which would aid to resolve one bottleneck in multiple pathway expression in P. patens and other plants.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Diallylsulfide attenuates excessive collagen production and apoptosis in a rat model of bleomycin induced pulmonary fibrosis through the involvement of protease activated receptor-2

Pulmonary fibrosis (PF) can be a devastating lung disease. It is primarily caused by inflammation leading to severe damage of the alveolar epithelial cells. The pathophysiology of PF is not yet been clearly defined, but studying lung parenchymal injury by involving reactive oxygen species (ROS) through the activation of protease activated receptor-2 (PAR-2) may provide promising results. PAR-2 is a G-protein coupled receptor is known to play an important role in the development of PF. In this study, we investigated the inhibitory role of diallylsulfide (DAS) against ROS mediated activation of PAR-2 and collagen production accompanied by epithelial cell apoptosis. Bleomycin induced ROS levels may prompt to induce the expression of PAR-2 as well as extracellular matrix proteins (ECM), such as MMP 2 and 9, collagen specific proteins HSP-47, α-SMA, and cytokines IL-6, and IL-8RA. Importantly DAS treatment effectively decreased the expression of all these proteins. The inhibitory effect of DAS on profibrotic molecules is mediated by blocking the ROS level. To identify apoptotic signaling as a mediator of PF induction, we performed apoptotic protein expression, DNA fragmentation analysis and ultrastructural details of the lung tissue were performed. DAS treatment restored all these changes to near normalcy. In conclusion, treatment of PF bearing rats with DAS results in amelioration of the ROS production, PAR-2 activation, ECM production, collagen synthesis and alveolar epithelial cell apoptosis during bleomycin induction. We attained the first evidence that treatment of DAS decreases the ROS levels and may provide a potential therapeutic effect attenuating bleomycin induced PF. - Highlights: • DAS inhibits PAR-2 activity; bleomycin stimulates PAR-2 activity. • Increase in PAR-2 activity is correlated with pulmonary fibrosis • DAS reduces pro-inflammatory activity linked to facilitating pulmonary fibrosis. • DAS inhibits apoptosis of alveolar epithelial cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

TRPM7 channel regulates PDGF-BB-induced proliferation of hepatic stellate cells via PI3K and ERK pathways

TRPM7, a non-selective cation channel of the TRP channel superfamily, is implicated in diverse physiological and pathological processes including cell proliferation. Recently, TRPM7 has been reported in hepatic stellate cells (HSCs). Here, we investigated the contribution role of TRPM7 in activated HSC-T6 cell (a rat hepatic stellate cell line) proliferation. TRPM7 mRNA and protein were measured by RT-PCR and Western blot in rat model of liver fibrosis in vivo and PDGF-BB-activated HSC-T6 cells in vitro. Both mRNA and protein of TRPM7 were dramatically increased in CCl{sub 4}-treated rat livers. Stimulation of HSC-T6 cells with PDGF-BB resulted in a time-dependent increase of TRPM7 mRNA and protein. However, PDGF-BB-induced HSC-T6 cell proliferation was inhibited by non-specific TRPM7 blocker 2-aminoethoxydiphenyl borate (2-APB) or synthetic siRNA targeting TRPM7, and this was accompanied by downregulation of cell cycle proteins, cyclin D1, PCNA and CDK4. Blockade of TRPM7 channels also attenuated PDGF-BB induced expression of myofibroblast markers as measured by the induction of α-SMA and Col1α1. Furthermore, the phosphorylation of ERK and AKT, associated with cell proliferation, decreased in TRPM7 deficient HSC-T6 cells. These observations suggested that TRPM7 channels contribute to perpetuated fibroblast activation and proliferation of PDGF-BB induced HSC-T6 cells via the activation of ERK and PI3K pathways. Therefore, TRPM7 may constitute a useful target for the treatment of liver fibrosis. - Highlights: • Upregulation of TRPM7 mRNA and protein in the fibrotic livers from CCl{sub 4}-treated rats. • Increasing expression of TRPM7 mRNA and protein during HSC activation. • Blockade of TRPM7 inhibited the PDGF-BB induced proliferation of HSC-T6 cells. • Blockade of TRPM7 decreased α-SMA and Col1α1 expressions in activated HSC-T6 cells. • TRPM7 up-regulation contributes to the activation of ERK and AKT pathways.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

TGF-β1-elevated TRPM7 channel regulates collagen expression in hepatic stellate cells via TGF-β1/Smad pathway

Transdifferentiation of hepatic stellate cells (HSCs) into myofibroblasts plays a critical role in the development of liver fibrosis, since myofibroblasts are the key cells responsible for excessive deposition of ECM proteins. Transient receptor potential melastatin 7 (TRPM7), a non-selective cation channel with protein serine/threonine kinase activity, has been demonstrated to function in the proliferation of activated HSCs. Here, we investigated the functional role of TRPM7 in collagen deposition in activated HSC-T6 cells (a rat hepatic stellate cell line). TRPM7 mRNA and protein were measured by Real-time PCR and Western blot in TGF-β1-activated HSC-T6 cells in vitro. Results demonstrated that TRPM7 protein was dramatically increased in fibrotic human livers. Stimulation of HSC-T6 cells with TGF-β1 increased TRPM7 mRNA and protein level in a time-dependent manner. Nevertheless, TGF-β1-elicited upregulation of TRPM7 in HSC-T6 cells was abrogated by SB431542 (TGF-β1 receptor blocker) or SIS3 (inhibitor of Smad3 phosphorylation). Additionally, blockade of TRPM7 channels with non-specific TRPM7 blocker 2-APB or synthetic siRNA targeting TRPM7 attenuated TGF-β1-induced expression of myofibroblast markers, as measured by the induction of α-SMA and Col1α1. Silencing TRPM7 also increased the ratio of MMPs/TIMPs by increasing MMP-13 expression and decreasing TIMP-1 and TIMP-2 levels. Strikingly, phosphorylation of p-Smad2 and p-Smad3, associated with collagen production, was decreased in TRPM7 deficient HSC-T6 cells. These observations suggested that TGF-β1 elevates TRPM7 expression in HSCs via Smad3-dependant mechanisms, which in turn contributes Smad protein phosphorylation, and subsequently increases fibrous collagen expression. Therefore, TRPM7 may constitute a useful target for the treatment of liver fibrosis. - Highlights: • Upregulation of TRPM7 protein in human fibrotic livers • Upregulation of TRPM7 by TGF-β1 elicited Smad signaling in HSC-T6 cells • Blockade of TRPM7 decreased α-SMA and Col1α1 expressions in activated HSC-T6 cells • Silencing of TRPM7 led to collagen degradation in TGF-β1 stimulated HSC-T6 cells • TRPM7 upregulation contributes to the activation of TGF-β1/Smad pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Silent information regulator 1 (SIRT1) ameliorates liver fibrosis via promoting activated stellate cell apoptosis and reversion

SIRT1 (silent information regulator 1), a conserved NAD +-dependent histone deacetylase, is closely related with various biological processes. Moreover, the important role of SIRT1 in alcoholic liver disease, nonalcoholic fatty liver and HCC had been widely reported. Recently, a novel role of SIRT1 was uncovered in organ fibrosis diseases. Here, we investigated the inhibitory effect of SIRT1 in liver fibrogenesis. SIRT1 protein was dramatically decreased in CCl4-treated mice livers. Stimulation of LX-2 cells with TGF-β1 also resulted in a significant suppression of SIRT1 protein. Nevertheless, TGF-β1-induced LX-2 cell activation was inhibited by SIRT1 plasmid, and this was accompanied by up-regulation of cell apoptosis-related proteins. Overexpression of SIRT1 also attenuated TGF-β1-induced expression of myofibroblast markers α-SMA and COL1a. However, the important characteristic of the recovery of liver fibrosis is not only the apoptosis of activated stellate cells but also the reversal of the myofibroblast-like phenotype to a quiescent-like phenotype. Restoration of SIRT1 protein was observed in the in vivo spontaneously liver fibrosis reversion model and in vitro MDI (isobutylmethylxanthine, dexamethasone, and insulin)-induced reversed stellate cells, and forced expression of SIRT1 also promoted the reversal of activated stellate cells. Furthermore, lncRNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) was increased in liver fibrosis. RNAi-mediated suppression of MALAT1 resulted in a decrease of myofibroblast markers and restoration of SIRT1 protein. These observations suggested that SIRT1 contributed to apoptosis and reversion of activated LX-2 cells and SIRT1 might be regulated by MALAT1 in liver fibrosis. Therefore, SIRT1 could be considered as a valuable therapeutic target for translational studies of liver fibrosis. - Highlights: • This is the first report of SIRT1 expression and function in liver fibrogenesis and reversion. • Aberrant expression of SIRT1 might just occur at a post-transcriptional level. • LncRNA MALAT1 might be responsible for the changes of SIRT1 in liver fibrosis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

PTP1B confers liver fibrosis by regulating the activation of hepatic stellate cells

Liver fibrosis is a reversible wound-healing response to chronic hepatic injuries. Activation of hepatic stellate cells (HSCs) plays a pivotal role in the development of hepatic fibrosis. The currently accepted mechanism for the resolution of liver fibrosis is the apoptosis and inactivation of activated HSCs. Protein tyrosine phosphatase 1B (PTP1B), a prototype of non-receptor protein tyrosine phosphatase, is proved to be a vital modulator in cardiac fibrogenesis. However, the precise role of PTP1B on liver fibrosis and HSC activation is still unclear. Our study showed that the expression of PTP1B was elevated in fibrotic liver but reduced after spontaneous recovery. Moreover, stimulation of HSC-T6 cells with transforming growth factor-β1 (TGF-β1) resulted in a dose/time-dependent increase of PTP1B mRNA and protein. Co-incubation of HSC-T6 cells with PTP1B-siRNA inhibited the cell proliferation and activation induced by TGF-β1. Additionally, both mRNA and protein of PTP1B were dramatically decreased in inactivated HSCs after treated with adipogenic differentiation mixture (MDI). Over-expression of PTP1B hindered the inactivation of HSC-T6 cells induced by MDI. These observations revealed a regulatory role of PTP1B in liver fibrosis and implied PTP1B as a potential therapeutic target. - Highlights: • The expression of PTP1B in the fibrotic livers and recovery livers • The expression of PTP1B in activated and inactivated HSCs • Blockade of PTP1B inhibited the TGF-β1-induced proliferation and activation of HSCs. • Over-expression of PTP1B abolished the inactivation of HSCs induced by MDI.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Dioscin alleviates BDL- and DMN-induced hepatic fibrosis via Sirt1/Nrf2-mediated inhibition of p38 MAPK pathway

Oxidative stress is involved in hepatic stellate cells (HSCs) activation and extracellular matrix overproduction. We previously reported the promising effects of dioscin against CCl{sub 4}-induced liver fibrosis, but its effects and mechanisms on BDL- and DMN-induced liver fibrosis remain unknown. The results in the present study indicated that dioscin significantly inhibited HSCs activation and attenuated hepatic fibrosis in rats. Furthermore, dioscin markedly up-regulated the levels of sirtuin 1 (Sirt1), HO-1, GST, GCLC and GCLM via increasing the nuclear translocation of nuclear erythroid factor 2-related factor 2 (Nrf2), which in turn inhibited mitogen-activated protein kinase 14 (p38 MAPK) phosphorylation and reduced the levels of COL1A1, COL3A1, α-SMA and fibronectin. These results were further validated by knockdown of Sirt1 and Nrf2 using siRNAs silencing, and abrogation of p38 MAPK using SB-203580 (a p38 MAPK inhibitor) in HSC-T6 and LX-2 cells. Collectively, our findings confirmed the potent effects of dioscin against liver fibrosis and also provided novel insights into the mechanisms of this compound as a candidate for the prevention of liver fibrosis in the future. - Highlights: • Dioscin showed potent effects against BDL- and DMN-induced liver fibrosis in rats. • Dioscin significantly suppressed oxidative stress. • Dioscin triggered Sirt1/Nrf2-mediated inhibition of p38 MAPK pathway. • Dioscin should be developed as a novel candidate to treat liver fibrosis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Alteration of canonical and non-canonical WNT-signaling by crystalline silica in human lung epithelial cells

Growth and development of the mature lung is a complex process orchestrated by a number of intricate developmental signaling pathways. Wingless-type MMTV-integration site (WNT) signaling plays critical roles in controlling branching morphogenesis cell differentiation, and formation of the conducting and respiratory airways. In addition, WNT pathways are often re-activated in mature lungs during repair and regeneration. WNT- signaling has been elucidated as a crucial contributor to the development of idiopathic pulmonary fibrosis as well as other hyper-proliferative lung diseases. Silicosis, a detrimental occupational lung disease caused by excessive inhalation of crystalline silica dust, is hallmarked by repeated cycles of damaging inflammation, epithelial hyperplasia, and formation of dense, hyalinized nodules of whorled collagen. However, mechanisms of epithelial cell hyperplasia and matrix deposition are not well understood, as most research efforts have focused on the pronounced inflammatory response. Microarray data from our previous studies has revealed a number of WNT-signaling and WNT-target genes altered by crystalline silica in human lung epithelial cells. In the present study, we utilize pathway analysis to designate connections between genes altered by silica in WNT-signaling networks. Furthermore, we confirm microarray findings by QRT-PCR and demonstrate both activation of canonical (β-catenin) and down-regulation of non-canonical (WNT5A) signaling in immortalized (BEAS-2B) and primary (PBEC) human bronchial epithelial cells. These findings suggest that WNT-signaling and cross-talk with other pathways (e.g. Notch), may contribute to proliferative, fibrogenic and inflammatory responses to silica in lung epithelial cells. - Highlights: • Pathway analysis reveals silica-induced WNT-signaling in lung epithelial cells. • Silica-induced canonical WNT-signaling is mediated by autocrine/paracrine signals. • Crystalline silica decreases non-canonical WNT5A signaling. • Microarray reveals WNT as a novel complex signaling network in silica-mediated injury.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Methylation of Septin9 mediated by DNMT3a enhances hepatic stellate cells activation and liver fibrogenesis

Liver fibrosis, resulting from chronic and persistent injury to the liver, is a worldwide health problem. Advanced liver fibrosis results in cirrhosis, liver failure and even hepatocellular cancer (HCC), often eventually requiring liver transplantation, poses a huge health burden on the global community. However, the specific pathogenesis of liver fibrosis remains not fully understood. Numerous basic and clinical studies have provided evidence that epigenetic modifications, especially DNA methylation, might contribute to the activation of hepatic stellate cells (HSCs), the pivotal cell type responsible for the fibrous scar in liver. Here, reduced representation bisulfite sequencing (RRBS) and bisulfite pyrosequencing PCR (BSP) analysis identified hypermethylation status of Septin9 (Sept9) gene in liver fibrogenesis. Sept9 protein was dramatically decreased in livers of CCl4-treated mice and immortalized HSC-T6 cells exposed to TGF-β1. Nevertheless, the suppression of Sept9 could be blocked by DNMT3a-siRNA and DNA methyltransferase inhibitor, 5-aza-2′-deoxycytidine (5-azadC). Overexpressed Sept9 attenuated TGF-β1-induced expression of myofibroblast markers α-SMA and Col1a1, accompanied by up-regulation of cell apoptosis-related proteins. Conversely, RNAi-mediated silencing of Sept9 enhanced accumulation of extracellular matrix. These observations suggested that Sept9 contributed to alleviate liver fibrosis might partially through promoting activated HSCs apoptosis and this anti-fibrogenesis effect might be blocked by DNMT-3a mediated methylation of Sept9. Therefore, pharmacological agents that inhibit Sept9 methylation and increase its expression could be considered as valuable treatments for liver fibrosis. - Highlights: • This is the first report of Sept9 methylation and function in liver fibrosis. • Ectopic expression of Sept9 could block the liver fibrogenesis. • DNMT3a might be responsible for the suppression of Sept9 in liver fibrosis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Morphogenesis of respiratory syncytial virus in human primary nasal ciliated epithelial cells occurs at surface membrane microdomains that are distinct from cilia

The distribution of cilia and the respiratory syncytial virus (RSV) nucleocapsid (N) protein, fusion (F) protein, attachment (G) protein, and M2-1 protein in human ciliated nasal epithelial cells was examined at between 1 and 5 days post-infection (dpi). All virus structural proteins were localized at cell surface projections that were distinct from cilia. The F protein was also trafficked into the cilia, and while its presence increased as the infection proceeded, the N protein was not detected in the cilia at any time of infection. The presence of the F protein in the cilia correlated with cellular changes in the cilia and reduced cilia function. At 5 dpi extensive cilia loss and further reduced cilia function was noted. These data suggested that although RSV morphogenesis occurs at non-cilia locations on ciliated nasal epithelial cells, RSV infection induces changes in the cilia body that leads to extensive cilia loss. - Highlights: • Respiratory syncytial virus (RSV) infects nasal ciliated epithelial cells. • Virus morphogenesis occurs within filamentous projections distinct from cilia. • The RSV N protein was not detected in the cilia at any time during infection. • Trafficking of the F protein into the cilia occurred early in infection. • Presence of the F protein in cilia correlated with impaired cilia function.

60 APPLIED LIFE SCIENCES↗