排序方式: 共有27条查询结果,搜索用时 15 毫秒
11.
Induction of renal fibrotic genes by TGF-β1 requires EGFR activation,p53 and reactive oxygen species
Rohan Samarakoon Amy D. Dobberfuhl Catherine Cooley Jessica M. Overstreet Samik Patel Roel Goldschmeding Kirstan K. Meldrum Paul J. Higgins 《Cellular signalling》2013,25(11):2198-2209
While transforming growth factor-β (TGF-β1)-induced SMAD2/3 signaling is a critical event in the progression of chronic kidney disease, the role of non-SMAD mechanisms in the orchestration of fibrotic gene changes remains largely unexplored. TGF-β1/SMAD3 pathway activation in renal fibrosis (induced by ureteral ligation) correlated with epidermal growth factor receptorY845 (EGFRY845) and p53Ser15 phosphorylation and induction of disease causative target genes plasminogen activator inhibitor-1 (PAI-1) and connective tissue growth factor (CTGF) prompting an investigation of the mechanistic involvement of EGFR and tumor suppressor p53 in profibrotic signaling. TGF-β1, PAI-1, CTGF, p53 and EGFR were co-expressed in the obstructed kidney localizing predominantly to the tubular and interstitial compartments. Indeed, TGF-β1 activated EGFR and p53 as well as SMAD2/3. Genetic deficiency of either EGFR or p53 or functional blockade with AG1478 or Pifithrin-α, respectively, effectively inhibited PAI-1and CTGF induction and morphological transformation of renal fibroblasts as did SMAD3 knockdown or pretreatment with the SMAD3 inhibitor SIS3. Reactive oxygen species (ROS)-dependent mechanisms initiated by TGF-β1 were critical for EGFRY845 and p53Ser15 phosphorylation and target gene expression. The p22Phox subunit of NADPH oxidase was also elevated in the fibrotic kidney with an expression pattern similar to p53 and EGFR. EGF stimulation alone initiated, albeit delayed, c-terminal SMAD3 phosphorylation (that required the TGF-β1 receptor) and rapid ERK2 activation both of which are necessary for PAI-1 and CTGF induction in renal fibroblasts. These data highlight the extensive cross-talk among SMAD2/3, EGFR and p53 pathways essential for expression of TGF-β1-induced fibrotic target genes. 相似文献
12.
Kalpa Wishvajith Samarakoon Kwon O-Nam Ju-Young Ko Ji-Hyeok Lee Min-Cheol Kang Daekyung Kim Joon Baek Lee Jung-Suck Lee You-Jin Jeon 《Journal of applied phycology》2013,25(5):1595-1606
Isolation of bioactive compounds and commercialization of marine microalgae sources are interesting targets in future marine biotechnology. Cultured biomass of the marine microalga, Nannochloropsis oculata, was used to purify angiotensin-I converting enzyme (ACE) inhibitory peptides using proteases including pepsin, trypsin, α-chymotrypsin, papain, alcalase, and neutrase. The pepsin hydrolysate exhibited the highest ACE inhibitory activity, compared to the other hydrolysates and then was separated into three fractions (F1, F2, and F3) using Sephadex G-25 gel filtration column chromatography. First fraction (F1) showed the highest ACE inhibitory activity and it was further purified into two fractions (F1-1 and F1-2) using reverse-phase high-performance liquid chromatography. The IC50 value of purified ACE inhibitory peptides were 123 and 173 μM and identified as novel peptides, Gly-Met-Asn-Asn-Leu-Thr-Pro (GMNNLTP; MW, 728 Da) and Leu-Glu-Gln (LEQ; MW, 369 Da), respectively. In addition, nitric oxide production level (%) was significantly increased by the purified peptide (Gly-Met-Asn-Asn-Leu-Thr-Pro) compared to the purified peptide (Leu-Glu-Gln) and other treated pepsin hydrolysate fractions on human umbilical vein endothelial cells (HUVECs). Cell viability assay showed no cytotoxicity on HUVECs with the treated purified peptides and fractions. These results suggest that the isolated peptides from cultured marine microalga, N. oculata protein sources may have potentiality to use commercially as ACE inhibitory agents in functional food industry. 相似文献
13.
14.
Kerry C. Ryan Zahra Ashkavand Shaarika Sarasija Jocelyn T. Laboy Rohan Samarakoon Kenneth R. Norman 《Aging cell》2021,20(10)
Metabolic dysfunction and protein aggregation are common characteristics that occur in age‐related neurodegenerative disease. However, the mechanisms underlying these abnormalities remain poorly understood. We have found that mutations in the gene encoding presenilin in Caenorhabditis elegans, sel‐12, results in elevated mitochondrial activity that drives oxidative stress and neuronal dysfunction. Mutations in the human presenilin genes are the primary cause of familial Alzheimer''s disease. Here, we demonstrate that loss of SEL‐12/presenilin results in the hyperactivation of the mTORC1 pathway. This hyperactivation is caused by elevated mitochondrial calcium influx and, likely, the associated increase in mitochondrial activity. Reducing mTORC1 activity improves proteostasis defects and neurodegenerative phenotypes associated with loss of SEL‐12 function. Consistent with high mTORC1 activity, we find that SEL‐12 loss reduces autophagosome formation, and this reduction is prevented by limiting mitochondrial calcium uptake. Moreover, the improvements of proteostasis and neuronal defects in sel‐12 mutants due to mTORC1 inhibition require the induction of autophagy. These results indicate that mTORC1 hyperactivation exacerbates the defects in proteostasis and neuronal function in sel‐12 mutants and demonstrate a critical role of presenilin in promoting neuronal health. 相似文献
15.
TGF-beta 1-induced PAI-1 expression is E box/USF-dependent and requires EGFR signaling 总被引:4,自引:0,他引:4
Kutz SM Higgins CE Samarakoon R Higgins SP Allen RR Qi L Higgins PJ 《Experimental cell research》2006,312(7):1093-1105
16.
Rajasekaran K Chu H Kumar P Xiao Y Tinguely M Samarakoon A Kim TW Li X Thakar MS Zhang J Malarkannan S 《The Journal of biological chemistry》2011,286(36):31213-31224
Carma1, a caspase recruitment domain-containing membrane-associated guanylate kinase, initiates a unique signaling cascade via Bcl10 and Malt1 in NK cells. Carma1 deficiency results in reduced phosphorylation of JNK1/2 and activation of NF-κB that lead to impaired NK cell-mediated cytotoxicity and cytokine production. However, the precise identities of the downstream signaling molecules that link Carma1 to these effector functions were not defined. Here we show that transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) is abundantly present in NK cells, and activation via NKG2D results in its phosphorylation. Lack of Carma1 considerably reduced TAK1 phosphorylation, demonstrating the dependence of TAK1 on Carma1 in NKG2D-mediated NK cell activations. Pharmacological inhibitor to TAK1 significantly reduced NK-mediated cytotoxicity and its potential to generate IFN-γ, GM-CSF, MIP-1α, MIP-1β, and RANTES. Conditional in vivo knockdown of TAK1 in NK cells from Mx1Cre(+)TAK1(fx/fx) mice resulted in impaired NKG2D-mediated cytotoxicity and cytokine/chemokine production. Inhibition or conditional knockdown of TAK1 severely impaired the NKG2D-mediated phosphorylation of ERK1/2 and JNK1/2 and activation of NF-κB and AP1. Our results show that TAK1 links Carma1 to NK cell-mediated effector functions. 相似文献
17.
Pubudu Saneth Samarakoon Hanne S?rmo Sorte Bj?rn Evert Kristiansen Tove Skodje Ying Sheng Geir E Tj?nnfjord Barbro Stadheim Asbj?rg Stray-Pedersen Olaug Kristin R?dningen Robert Lyle 《BMC genomics》2014,15(1)
Background
With advances in next generation sequencing technologies and genomic capture techniques, exome sequencing has become a cost-effective approach for mutation detection in genetic diseases. However, computational prediction of copy number variants (CNVs) from exome sequence data is a challenging task. Whilst numerous programs are available, they have different sensitivities, and have low sensitivity to detect smaller CNVs (1–4 exons). Additionally, exonic CNV discovery using standard aCGH has limitations due to the low probe density over exonic regions. The goal of our study was to develop a protocol to detect exonic CNVs (including shorter CNVs that cover 1–4 exons), combining computational prediction algorithms and a high-resolution custom CGH array.Results
We used six published CNV prediction programs (ExomeCNV, CONTRA, ExomeCopy, ExomeDepth, CoNIFER, XHMM) and an in-house modification to ExomeCopy and ExomeDepth (ExCopyDepth) for computational CNV prediction on 30 exomes from the 1000 genomes project and 9 exomes from primary immunodeficiency patients. CNV predictions were tested using a custom CGH array designed to capture all exons (exaCGH). After this validation, we next evaluated the computational prediction of shorter CNVs. ExomeCopy and the in-house modified algorithm, ExCopyDepth, showed the highest capability in detecting shorter CNVs. Finally, the performance of each computational program was assessed by calculating the sensitivity and false positive rate.Conclusions
In this paper, we assessed the ability of 6 computational programs to predict CNVs, focussing on short (1–4 exon) CNVs. We also tested these predictions using a custom array targeting exons. Based on these results, we propose a protocol to identify and confirm shorter exonic CNVs combining computational prediction algorithms and custom aCGH experiments.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-661) contains supplementary material, which is available to authorized users. 相似文献18.
19.
20.
Effects of root architecture, physical tree characteristics, and soil shear strength on overturning moment due to flooding
were investigated using Salix babylonica and Juglans ailanthifolia, exotic and invasive plants in Japanese rivers. Tree-pulling experiments that simulated flood action were conducted, and
the resulting damage was examined to assess the effects of physical tree characteristics and root architecture on the maximum
resistive bending moment (M
max) for overturning. In situ soil shear strength tests were conducted to measure soil strength parameters. The effects of species
differences on the M
max were examined by analyzing root architecture. S. babylonica has a heart-root system that produces a greater overturning moment due to the strong root anchorage and the large amount
of substrate that must be mobilized during overturning. J. ailanthifolia has a plate-root system that produces a smaller overturning moment. However, trees with the plate-root system may withstand
overturning better due to an increased root:shoot ratio. The results of the study show that the M
max of a tree for overturning had significant (P < 0.05) correlations with a tree’s physical characteristics, including height (H), trunk diameter at breast height (D
bh), D
bh2, height multiplied by the second power of D
bh (trunk volume index H × D
bh2), and root–soil plate depth (R
d), and root–soil plate radius (R
r). Considering the strategy of J. ailanthifolia to increase the root:shoot ratio for anchoring in the substrate, the trunk volume index (H × D
bh2) is a better parameter than D
bh2 because it indirectly involves the difference in below-ground volume and surface area. Different soil cohesion values were
found at different experimental sites, and the average M
max for overturning each species decreased linearly with increasing soil cohesion. 相似文献