SEARCH · Search NASA
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Highlights: • CD95 triggers death as well as non-death activities - e.g. proliferation, invasion and inflammation. • The CD95-Fc fusion protein, APG101, can serve as a tool to manipulate CD95-mediated non-death and death events. • The manipulation of the new immunological Annexin checkpoint system has an impact on peripheral tolerance towards apoptotic cells.
Retinal microvascular abnormality is an important pathological feature of diabetic retinopathy. Herein, we report the role of lncRNA-RNCR3 in diabetes mellitus-induced retinal microvascular abnormalities. We show that RNCR3 is significantly up-regulated upon high glucose stress in vivo and in vitro. RNCR3 knockdown alleviates retinal vascular dysfunction in vivo, as shown by decreased acellular capillaries, decreased vascular leakage, and reduced inflammatory response. RNCR3 knockdown decreases retinal endothelial cell proliferation, and reduces cell migration and tube formation in vitro. RNCR3 regulates endothelial cell function through RNCR3/KLF2/miR-185-5p regulatory network. RNCR3 inhibition may be a treatment option for the prevention of diabetes mellitus-induced retinal microvascular abnormalities. - Highlights: • RNCR3 expression is significantly up-regulated upon high glucose stress. • RNCR3 knockdown alleviates retinal vascular dysfunction in vivo. • RNCR3 regulates retinal endothelial cell function in vitro. • RNCR3 regulates retinal endothelial cell function via RNCR3/KLF2/miR-185-5p pathway.
Recently, long non-coding RNAs (lncRNAs) have been shown to have critical regulatory roles in tumourigenesis. Increasing evidence has suggested that lncRNA NEAT1 has been implicated in various types of human cancer. However, the potential biological roles and regulatory mechanisms of NEAT1 in pancreatic cancer (PC) remains unclear. Here, we found that the expression level of NEAT1 was higher in PC tissues compared to the corresponding non-tumor tissues. Besides, our findings indicate that high NEAT1 expression level is closely correlated with tumor progression and poor survival in PC patients. Furthermore, we also found that knockdown of NEAT1 remarkably suppressed cell proliferation by inducing cell cycle arrest and apoptosis promotion in PC cells. Moreover, bioinformatics analysis and luciferase reporter assay revealed that NEAT1 directly bound to the miR-506-3p, which has been reported to act as a tumor suppressor in diverse cancers. Additionally, our results confirmed that the tumor-promoting effects of NEAT1 in PC cells is at least partly through negative modulation of miR-506-3p. Overall, our results suggested that NEAT1 functions as an oncogenic lncRNA in PC, which could be a novel diagnostic and therapeutic target for PC. - Highlights: • Upregulation of NEAT1 expression was significantly associated with the poor survival in PC patients. • Knockdown of NEAT1 can suppress PC cells growth by inducing cell cycle arrest and apoptosis promotion in vitro study. • NEAT1 functions as an oncogene in pancreatic cancer by acting as a competing endogenous RNA for miR-506-3p. • The tumor-suppressive effects of NEAT1 knockdown in PC cells was partially reversed by miR-506-3p inhibitor.
Parkinson's disease (PD) is a progressive neurodegenerative disorder in which dopamine (DA) neurons in the substantia nigra pars compacta (SNpc) region are selectively destroyed. Sonic hedgehog (Shh) has been well known to play a key role in a variety of processes such as embryogenesis, cell proliferation and protection, and tissue repair during inflammation. However, the evidences for the innate role of Shh in adult brain injury are presently lacking and studies have been needed to unveil the importance of Shh in the process of neurodegeneration. Here, we investigated the role of Shh in the pathologic progress of Parkinson's disease in MPTP-induced animal model system. Interestingly, we observed that Shh expression was gradually increased in MPTP affected SNpc region. Activated microglia exclusively expressed SHH in vivo and we could recapitulate Shh induction in activated cultured primary microglia cells. Using the SHH responsive Cre-loxP binary genetic reporter transgenic mouse system, we also found that most of the cell types except for oligodendrocyte in the SNpc region reacted to the SHH by MPTP injection. Taken together, activated microglia induced Shh expression and most neural cells except oligodendrocyte responded to microglia-derived SHH in MPTP-treated SN. These results suggest that SHH in activated microglia by MPTP-injection might be involved in the innate processes of recovery from neurotoxin induced injury in the PD animal model system. - Highlights: • Sonic hedgehog (Shh) was induced by MPTP neurotoxin at the Substantia Nigra (SN) in vivo. • Activated microglia are major cell type for SHH expression in vivo and in vitro. • Different types of cells in the brain, except oligodendrocyte, respond to microglia-derived SHH in SN region.
Betulin, a natural product isolated from the bark of the birch trees, exhibits multiple anticancer effects. Activation of mTOR signaling pathway has been found in numerous cancers, including renal cell carcinoma (RCC). Here, we attempted to study whether mTOR signaling was essential for betulin to treat RCC. Based on cell survival and colony formation assays, we found that mTOR hyperactive RCC cell line 786-O cells were more sensitive to betulin treatment compared with mTOR-inactive Caki-2 cells. Knockdown of TSC2 in Caki-2 cells had similar results to 786-O cells, and mTOR silencing in 786-O cells rescued the inhibitory effect of betulin, indicating that betulin inhibited RCC cell proliferation in an mTOR-dependent manner. Furthermore, betulin treatment decreases the levels of glucose consumption and lactate production in 786-O cells, while minimal effects were observed in Caki-2 cells. In addition, betulin significantly inhibited the expression of PKM2 and HK2 in 786-O cells. Finally, knockdown of PKM2 or HK2 in 786-O reversed the anti-proliferative effects of betulin, and overexpression of PKM2 or HK2 in Caki-2 cells enhanced the sensitivity to betulin treatment. Taken together, these findings demonstrated the critical role of mTOR activation in RCC cells to betulin treatment, suggesting that betulin might be valuable for targeted therapies in RCC patients with mTOR activation.
ASPP2 is a tumor suppressor that works, at least in part, through enhancing p53-dependent apoptosis. We now describe a new ASPP2 isoform, ΔN-ASPP2, generated from an internal transcription start site that encodes an N-terminally truncated protein missing a predicted 254 amino acids. ΔN-ASPP2 suppresses p53 target gene transactivation, promoter occupancy, and endogenous p53 target gene expression in response to DNA damage. Moreover, ΔN-ASPP2 promotes progression through the cell cycle, as well as resistance to genotoxic stress-induced growth inhibition and apoptosis. Additionally, we found that ΔN-ASPP2 expression is increased in human breast tumors as compared to adjacent normal breast tissue; in contrast, ASPP2 is suppressed in the majority of these breast tumors. Together, our results provide insight into how this new ASPP2 isoform may play a role in regulating the ASPP2-p53 axis. - Highlights: • ΔN-ASPP2 is a N-terminal truncated ASPP2 isoform. • ΔN-ASPP2 antagonizes p53 transactivation and p53 promoter occupancy after cellular stress. • ΔN-ASPP2 promotes cell proliferation and suppresses cytotoxic damage-induced growth inhibition and apoptosis. • ΔN-ASPP2 is overexpressed in human breast tumors compared to adjacent normal breast tissue.
IgE is a key effector molecule in atopic diseases; however, the regulation mechanisms of IgE production in IgE B cells remain poorly understood. In the present study, we demonstrate that JSI-124 (cucurbitacin I), a selective STAT3 inhibitor, selectively inhibits production of IgE by a human IgE B cell line, CRL-8033 cells, while does not affect the IgG production by IgG B cell lines. In the aspect of molecular mechanism, we found that Igλ, but not Ighe, gene expression was suppressed by JSI-124. The above effects of JSI-124 were not mediated by affecting cellular proliferation or apoptosis. Furthermore, multiple B cell differentiation-related genes expression was not significantly affected by JSI-124. Taken together, we demonstrate a potential strategy of therapeutically suppressing IgE production without affecting IgG production in atopic patients. - Highlights: • JSI-124 inhibits IgE production in an IgE B cell line, CRL-8033 cells. • JSI-124 does not affect IgG production by IgG B cell lines. • JSI-124 inhibits IgE production mainly by suppressing transcription of Igλ.
Because of the high nutrient consumption and inadequate vascularization, solid tumor constantly undergoes metabolic stress during tumor development. Oncogenes and tumor suppressor genes participated in cancer cells' metabolic reprogramming. N-Myc downstream regulated gene 2 (NDRG2) is a recently identified tumor suppressor gene, but its function in cancer metabolism, particularly during metabolic stress, remains unclear. In this study, we found that NDRG2 overexpression significantly reduced hepatoma cell proliferation and enhanced cell apoptosis under glucose limitation. Moreover, NDRG2 overexpression aggravated energy imbalance and oxidative stress by decreasing the intracellular ATP and NADPH generation and increasing ROS levels. Strikingly, NDRG2 inhibited the activation of fatty acid oxidation (FAO), which preserves ATP and NADPH purveyance in the absence of glucose. Finally, mechanistic investigation showed that NDRG2 overexpression suppressed the glucose-deprivation induced AMPK/ACC pathway activation in hepatoma cells, whereas the expression of a constitutively active form of AMPK abrogated glucose-deprivation induced AMPK activation and cell apoptosis. Thus, as a negative regulator of AMPK, NDRG2 disturbs the induction of FAO genes by glucose limitation, leading to dysregulation of ATP and NADPH, and thus reduces the tolerance of hepatoma cells to glucose limitation. - Highlights: • NDRG2 overexpression reduces the tolerance of hepatoma cells to glucose limitation. • NDRG2 overexpression aggravates energy imbalance and oxidative stress under glucose deprivation. • NDRG2 overexpression disturbs the activation of FAO in hepatoma cells under glucose limitation. • NDRG2 overexpression inhibits the activation of AMPK/ACC pathway in hepatoma cells during glucose starvation.
Since the leading cause of death are cardiac diseases, engineered heart tissue (EHT) is one of the most appealing topics defined in tissue engineering and regenerative medicine fields. The importance of EHT is not only for heart regeneration but also for in vitro developing of cardiology. Cardiomyocytes could grow and commit more naturally in their microenvironment rather than traditional cultivation. Thus, this research tried to develop a set up on-a-chip to produce EHT based on chitosan hydrogel. Micro-bioreactor was hydrodynamically designed and simulated by COMSOL and produced via soft lithography process. Chitosan hydrogel was also prepared, adjusted, and assessed by XRD, FTIR and also its degradation rate and swelling ratio were determined. Finally, hydrogels in which mice cardiac progenitor cells (CPC) were loaded were injected into the micro-device chambers and cultured. Each EHT in every chamber was evaluated separately. Prepared EHTs showed promising results that expanded in them CPCs and work as an integrated syncytium. High cell density culture was the main accomplishment of this study. - Highlights: • An engineered heart tissue in its microenvironment at a perfused micro-bioreactor is proposed. • Cell proliferation of cardiac cells in high cell density is achievable in setup while sacrificing hydrogel is degrading. • 16 distinct heart tissue constructs in each run reduce the time and cost and increase the test results accuracy.
Insulin receptor substrates (IRSs) are phosphorylated by IGF-I receptor tyrosine kinase in a ligand-dependent manner. In turn, they bind to and activate effector proteins such as PI3K, leading to various cell responses including cell proliferation. We had reported that ubiquitin ligase Nedd4 induces mono-ubiquitination of IRS-2, thereby enhancing IRS-2 tyrosine phosphorylation, leading to increased IGF signaling and mitogenic activity. Here we show that ubiquitin-specific protease 15 (USP15) antagonizes the effect of Nedd4 on IRS-2. We identified USP15 as a protein that preferentially bound to IRS-2 when IRS-2 was conjugated with ubiquitin. In HEK293 cells, Nedd4 overexpression induced IRS-2 ubiquitination, which was decreased by USP15 co-expression while increased by USP15 knockdown. Nedd4 overexpression enhanced IGF-I-dependent IRS-2 tyrosine phosphorylation, and USP15 co-expression suppressed it. Conversely, USP15 knockdown increased IRS-2 tyrosine phosphorylation and downstream signaling in prostate cancer PC-3 cells. We concluded that USP15 attenuates IGF-I signaling by antagonizing Nedd4-induced IRS-2 ubiquitination. - Highlights: • Nedd4-induced mono-ubiquitination of IRS-2 enhances IRS-2-mediated IGF-I signaling. • We found that USP15 antagonizes Nedd4-induced IRS-2 ubiquitination. • We also found that USP15 attenuates IRS-2-mediated IGF-I signaling. • IRS-2 (de)ubiquitination by Nedd4 and USP15 determines IGF-I signal intensity.
Insights into the role of the mitogen-activated protein kinase (MAPK) pathway and immune checkpoints have led combined targeted therapy and immunotherapy to be a promising regimen. Trametinib, as a mitogen-activated extracellular signal-regulated kinase (MEK) inhibitor, has demonstrated effectiveness in patients with advanced melanoma. T cell immunoglobulin- and mucin-domain-containing molecule-3 (Tim-3), an immune checkpoint molecule, participates in multiple negative regulation of antitumor immunity. We for the first time to our knowledge reported the combination of trametinib and anti-Tim-3 monoclonal antibody (mAb) in treating B16-F10 melanoma mice. We discovered that trametinib remarkably promoted apoptosis and inhibited cell proliferation while inhibition of MEK improved the expression of Tim-3 and caused the decrease of CD8{sup +} T cells; to the contrary, anti-Tim-3 mAb enhanced antitumor immunity by stimulating CD8{sup +} T cells, thus the combined therapy produced potent antitumor effect cooperatively. Taken together, our study provides compelling evidence for combining trametinib and anti-Tim-3 mAb as a potential valuable regimen in treating melanoma. - Highlights: • The potent antitumor efficacy of combined trametinib and anti-Tim-3 mAb. • MEK inhibitor involves in up-regulation of Tim-3. • The combined medication provides new insights into melanoma treatment.
Background and objective: As a member of the epidermal growth factor family, amphiregulin contributes to the regulation of cell proliferation. Amphiregulin was reported to be upregulated in damaged lung tissues in patients with chronic obstructive pulmonary disease and asthma and in lung epithelial cells in a ventilator-associated lung injury model. In this study, we investigated the effect of amphiregulin on lipopolysaccharide (LPS)-induced acute lung injury in mice. Methods: Acute lung injury was induced by intranasal instillation of LPS in female C57BL/6 mice, and the mice were given intraperitoneal injections of recombinant amphiregulin or phosphate-buffered saline 6 and 0.5 h before and 3 h after LPS instillation. The effect of amphiregulin on apoptosis and apoptotic pathways in a murine lung alveolar type II epithelial cell line (LA-4 cells) were examined using flow cytometry and western blotting, respectively. Results: Recombinant amphiregulin suppressed epithelial cell apoptosis in LPS-induced lung injury in mice. Western blotting revealed that amphiregulin suppressed epithelial cell apoptosis by inhibiting caspase-8 activity. Conclusion: Amphiregulin signaling may be a therapeutic target for LPS-induced lung injury treatment through its prevention of epithelial cell apoptosis. - Highlights: • Amphiregulin suppresses epithelial cell apoptosis in LPS-induced lung injury in mice. • The mechanism relies on inhibiting caspase-8 activity. • Amphiregulin signaling may be a therapeutic target for LPS-induced lung injury.
Expansion of PD-1-expressing CD8{sup +} cytotoxic T lymphocytes (CTLs) and associated CTL exhaustion are chief issues for ineffective virus-elimination in chronic infectious diseases. PD-1 blockade using antagonistic anti-PD-L1 antibodies results in a moderate conversion of CTL exhaustion. We previously demonstrated that CD40L signaling of ovalbumin (OVA)-specific vaccine, OVA-Texo, converts CTL exhaustion via the activation of the mTORC1 pathway in OVA-expressing adenovirus (AdVova)-infected B6 mice showing CTL inflation and exhaustion. Here, we developed AdVova-infected B6 and transgenic CD11c-DTR (termed AdVova-B6 and AdVova-CD11c-DTR) mice with chronic infection, and assessed a potential effect of CD40 agonist on the conversion of CTL exhaustion and on a potential enhancement of PD-1 antagonist action in rescuing exhausted CTLs in our chronic infection models. We demonstrate that a single dose of anti-CD40 alone can effectively convert CTL exhaustion by activating the mTORC1 pathway, leading to CTL proliferation, up-regulation of an effector-cytokine IFN-γ and the cytolytic effect in AdVova-B6 mice. Using anti-CD4 antibody and diphtheria toxin (DT) to deplete CD4{sup +} T-cells and dendritic cells (DCs), we discovered that the CD40 agonist-induced conversion in AdVova-B6 and AdVova-CD11c-DTR mice is dependent upon host CD4{sup +} T-cell and DC involvements. Moreover, CD40 agonist significantly enhances PD-1 antagonist effectiveness in rescuing exhausted CTLs in chronic infection. Taken together, our data demonstrate the importance of CD40 signaling in the conversion of CTL exhaustion and its ability to enhance PD-1 antagonist action in rescuing exhausted CTLs in chronic infection. Therefore, our findings may positively impact the design of new therapeutic strategies for chronic infectious diseases. - Highlights: • Anti-CD40 agonistic Ab can convert CTL exhaustion in chronically infected mice. • The conversion relies on the activation of the mTORC1 pathway in exhausted CTLs. • The conversion depends on the involvement of host DCs and CD4{sup +} T cells. • Anti-CD40 Ab enhances the effect of PD-1 blockade in rescuing CTL exhaustion.
IL-6 exerts its pleiotropic activities on its target cells via the IL-6 alpha-receptor (IL-6R), which is expressed on a limited number of cell types. IL-6 can further signal via soluble forms of its receptor (sIL-6R), a process that has been termed trans-signaling. Recently, CD5 was described as an alternative alpha-receptor for IL-6 on B cells leading to the phosphorylation of the transcription factor STAT3 via the signal-transducing β-receptor gp130 in a Jak2-dependent manner. In this study, we sought to investigate whether IL-6 was also able to signal via soluble CD5 (sCD5) analogous to IL-6 trans-signaling. We show that IL-6 indeed binds to sCD5, but that this does not lead to the activation of signal transduction or cell proliferation. Furthermore, sCD5 did also not interfere with IL-6 classic signaling, suggesting that the affinity between the two proteins was too weak to provoke a biological effect. Thus, trans-signaling of IL-6 can only occur via sIL-6R, but not sCD5. - Highlights: • IL-6 binds to sCD5, albeit with less affinity compared to sIL-6R. • IL-6/sCD5 is not able to perform IL-6 trans-signaling. • sCD5 does not act as an inhibitory decoy receptor for IL-6.
25-hydroxycholesterol (25-HC) is enzymatically produced by cholesterol 25-hydorxylase in various organs and is involved in many processes, including lipid metabolism, inflammation and the immune response. However, the role of 25-HC in the migration and invasion of lung adenocarcinoma (ADC) cells remains largely unknown. In this study, we demonstrated that 0.1 μM 25-HC promoted ADC cell migration and invasion without affecting cell proliferation, especially after coculture with THP1-derived macrophages. Further investigation showed that 0.1 μM 25-HC significantly stimulated interleukin-1β (IL-1β) secretion in a coculture system and increased the expression of LXR and Snail. IL-1β also mimicked the effect of 25-HC. LXR knockdown notably blocked the 25-HC-induced Snail expression, migration and invasion in both the monoculture system and the coculture system, but it did not impact the effect of IL-1β, which suggested that IL-1β functioned in an LXR-independent manner. These results suggested that 25-HC promoted ADC cell migration and invasion in an LXR-dependent manner in the monoculture system but that in the coculture system, the 25-HC-induced IL-1β secretion enhanced the effect of 25-HC in an LXR-independent manner. - Highlights: • 25-hydroxycholesterol (25-HC) promoted ADC cells migration and invasion. • 25-HC induced IL-1β release in coculture of ADC cells and THP1-derived macrophage. • 25-HC induced a LXR-dependent Snail expression in ADC cells monoculture. • 25-HC-induced IL-1β in coculture system led to a LXR-independent Snail expression.
Smaller recombinant antibody fragments are now emerging as alternatives of conventional antibodies. Especially, immunoglobulin (Ig) constant CH2 domain and engineered CH2 with improved stability are promising as scaffolds for selection of specific binders to various antigens. We constructed a yeast display library based on an engineered human IgG1 CH2 scaffold with diversified loop regions. A group of CH2 binders were isolated from this yeast display library by panning against nucleolin, which is a tumor-associated antigen involved in cell proliferation, tumor cell growth and angiogenesis. Out of 20 mutants, we selected 3 clones exhibiting relatively high affinities to nucleolin on yeasts. However, recombinant CH2 mutants aggregated when they were expressed. To find the mechanism of the aggregation, we employed computational prediction approaches through structural homology models of CH2 binders. The analysis of potential aggregation prone regions (APRs) and solvent accessible surface areas (ASAs) indicated two hydrophobic residues, Val{sub 264} and Leu{sub 309}, in the β-sheet, in which replacement of both charged residues led to significant decrease of the protein aggregation. The newly identified CH2 binders could be improved to use as candidate therapeutics or research reagents in the future. - Highlights: • Novel engineered CH2 domains to nucleolin were identified from the yeast display CH2-based library. • Aggregation prone regions (APRs) were predicted through structural homology models CH2 domains. • The replacement of two hydrophobic residues in APRs significantly led to decrease of the CH2 aggregation.
Tumor cell metabolism is a promising target for various cancer treatments. Apart from aerobic glycolysis, cancer cell growth is dependent on glutamine (Gln) supply, leading to their survival and differentiation. Therefore, we examined whether treatment with TNF-related apoptosis-inducing ligand (TRAIL) sensitizes MDA-MB-231 cells to apoptosis under Gln deprivation condition (TRAIL/Gln deprivation). Gln deprivation decreased cell proliferation as expected, but did not induce remarkable cell death. TRAIL/Gln deprivation, however, significantly increased growth inhibition and morphological shrinkage of MDA-MB-231 cells compared to those induced by treatment with either Gln deprivation or TRAIL alone. Moreover, TRAIL/Gln deprivation upregulated the apoptotic sub-G{sub 1} phase accompanied with a remarkable decrease of pro-caspase-3, pro-caspase-9, and anti-apoptotic xIAP, and Bcl-2. Increased cleavage of PARP and pro-apoptotic Bid protein expression suggests that TRAIL/Gln deprivation triggers mitochondrion-mediated apoptosis in MDA-MB-231 cells. Additionally, TRAIL/Gln deprivation upregulated the expression of endoplasmic reticulum (ER) stress markers such as ATF4 and phosphorylated eIF2α, thereby enhancing the C/EBP homologous protein (CHOP) protein level. Transient knockdown of CHOP partically reversed TRAIL/Gln deprivation-mediated apoptosis. Accordingly, TRAIL/Gln deprivation enhanced the expression of death receptor 5 (DR5) and transient knockdown of DR5 completely restored TRAIL/Gln deprivation-mediated apoptosis. Taken together, our results suggest that Gln deprivation conditions can be used for the development of new therapies for TRAIL-resistant cancers.
Objectives: To investigate whether the activation of pancreatic stellate cells (PSCs) leads to pancreatic β-cell dysfunction in type 2 diabetes mellitus (T2DM). Methods: The pancreases of Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an animal model of T2DM, and patient with T2DM were analyzed. And the in vitro and in vivo effects of pirfenidone, an antifibrotic agent, on PSC activation, islet fibrosis, and β-cells were studied. Results: The extent of islet fibrosis and the percentage of activated PSCs, positive for α-smooth muscle actin, in the islets were significantly greater in OLETF rats compared with non-diabetic rats. Also, the extent of islet fibrosis in patients with T2DM was slightly greater compared with age- and BMI-matched non-diabetic patients. In rat PSCs cultured with high glucose for 72 h, pirfenidone produced decreases in cell proliferation, release of collagen, and the expression of fibronectin and connective tissue growth factor. Treatment of OLETF rats with pirfenidone for 16 weeks decreased the activation of PSCs and the extent of islet fibrosis, but did not enhance glucose tolerance, pancreatic insulin content, or β-cell mass. Conclusions: Activated PSCs in islets might lead to islet fibrosis in T2DM. However, PSC activation itself might not contribute significantly to progressive β-cell failure in T2DM. - Highlights: • Islet fibrosis developed progressively in OLETF rats, a model of type 2 diabetes. • PSCs in the islets became activated in OLETF rats. • Islet fibrosis was increased in patients with type 2 diabetes. • Pirfenidone attenuated the activation of PSCs and islet fibrosis in OLETF rats. • Pirfenidonet had no effects on glucose tolerance or on β-cells in OLETF rats.