Protection from diclofenac-induced small intestinal injury by the JNK inhibitor SP600125 in a mouse model of NSAID-associated enteropathy

2009 ◽  
Vol 297 (5) ◽  
pp. G990-G998 ◽  
Author(s):  
Veronica Ramirez-Alcantara ◽  
Amanda LoGuidice ◽  
Urs A. Boelsterli

Small intestinal ulceration, bleeding, and inflammation are major adverse effects associated with the use of diclofenac (DCF) or other nonsteroidal anti-inflammatory drugs (NSAIDs). The underlying mechanisms of DCF enteropathy are poorly understood, but there is increasing evidence that topical effects are involved. The aim of this study was to explore the role of c-Jun- N-terminal kinase (JNK) in DCF-induced enterocyte death because JNK not only regulates mitochondria-mediated apoptosis but also is a key node where many of the proximal stress signals converge. Male C57BL/6J mice were injected intraperitoneally with DCF or vehicle (Solutol HS-15), and the extent of small intestinal ulceration was determined. A single dose of DCF (60 mg/kg) produced numerous ulcers in the third and fourth quartiles of the jejunum and ileum, with maximal effects after 18 h and extensive recovery after 48 h. To study the molecular pathways leading to enterocyte injury, we isolated villi-enriched mucosal fractions from DCF-treated mice. Immunoblot studies with a phosphospecific JNK antibody revealed that JNK1/2 (p46) was activated at 6 h, leading to phosphorylation of the downstream target c-Jun. The levels of the JNK-regulated proapoptotic transcription factor C/EBP homologous protein (CHOP) were also increased after DCF. The selective JNK inhibitor SP600125 (30 mg/kg ip), given both 1 h before and 1 h after DCF, blocked JNK kinase activity and afforded significant protection against DCF enteropathy. In conclusion, these data demonstrate that the JNK pathway is critically involved in the pathogenesis of DCF-induced enteropathy and suggest a potential application of JNK inhibitors in the prevention of NSAID-induced enteropathy.

Metallomics ◽  
2021 ◽  
Vol 13 (3) ◽  
Author(s):  
Shi-Yong Zhu ◽  
Li-Li Liu ◽  
Yue-Qiang Huang ◽  
Xiao-Wei Li ◽  
Milton Talukder ◽  
...  

Abstract Selenoprotein N (SEPN1) is critical to the normal muscular physiology. Mutation of SEPN1 can raise congenital muscular disorder in human. It is also central to maturation and structure of skeletal muscle in chicken. However, human SEPN1 contained an EF-hand motif, which was not found in chicken. And the biochemical and molecular characterization of chicken SEPN1 remains unclear. Hence, protein domains, transcription factors, and interactions of Ca2+ in SEPN1 were analyzed in silico to provide the divergence and homology between chicken and human in this work. The results showed that vertebrates’ SEPN1 evolved from a common ancestor. Human and chicken's SEPN1 shared a conserved CUGS-helix domain with function in antioxidant protection. SEPN1 might be a downstream target of JNK pathway, and it could respond to multiple stresses. Human's SEPN1 might not combine with Ca2+ with a single EF-hand motif in calcium homeostasis, and chicken SEPN1 did not have the EF-hand motif in the prediction, indicating the EF-hand motif malfunctioned in chicken SEPN1.


2021 ◽  
Vol 22 (2) ◽  
pp. 866
Author(s):  
Joie L. Behrens ◽  
Nadine Schnepel ◽  
Kathrin Hansen ◽  
Karin Hustedt ◽  
Marion Burmester ◽  
...  

The intestinal absorption of phosphate (Pi) takes place transcellularly through the active NaPi-cotransporters type IIb (NaPiIIb) and III (PiT1 and PiT2) and paracellularly by diffusion through tight junction (TJ) proteins. The localisation along the intestines and the regulation of Pi absorption differ between species and are not fully understood. It is known that 1,25-dihydroxy-vitamin D3 (1,25-(OH)2D3) and phosphorus (P) depletion modulate intestinal Pi absorption in vertebrates in different ways. In addition to the apical uptake into the enterocytes, there are uncertainties regarding the basolateral excretion of Pi. Functional ex vivo experiments in Ussing chambers and molecular studies of small intestinal epithelia were carried out on P-deficient goats in order to elucidate the transepithelial Pi route in the intestine as well as the underlying mechanisms of its regulation and the proteins, which may be involved. The dietary P reduction had no effect on the duodenal and ileal Pi transport rate in growing goats. The ileal PiT1 and PiT2 mRNA expressions increased significantly, while the ileal PiT1 protein expression, the mid jejunal claudin-2 mRNA expression and the serum 1,25-(OH)2D3 levels were significantly reduced. These results advance the state of knowledge concerning the complex mechanisms of the Pi homeostasis in vertebrates.


Digestion ◽  
2010 ◽  
Vol 82 (3) ◽  
pp. 167-172 ◽  
Author(s):  
Shunji Fujimori ◽  
Yoko Takahashi ◽  
Tsuguhiko Seo ◽  
Katya Gudis ◽  
Akihito Ehara ◽  
...  

2017 ◽  
Vol 313 (3) ◽  
pp. C340-C351 ◽  
Author(s):  
Chongxu Zhang ◽  
Crystal Adamos ◽  
Myung-Jin Oh ◽  
Jugajyoti Baruah ◽  
Manuela A. A. Ayee ◽  
...  

Oxidized modifications of LDL (oxLDL) play a key role in the development of endothelial dysfunction and atherosclerosis. However, the underlying mechanisms of oxLDL-mediated cellular behavior are not completely understood. Here, we compared the effects of two major types of oxLDL, copper-oxidized LDL (Cu2+-oxLDL) and lipoxygenase-oxidized LDL (LPO-oxLDL), on proliferation of human aortic endothelial cells (HAECs). Cu2+-oxLDL enhanced HAECs’ proliferation in a dose- and degree of oxidation-dependent manner. Similarly, LPO-oxLDL also enhanced HAEC proliferation. Mechanistically, both Cu2+-oxLDL and LPO-oxLDL enhance HAEC proliferation via activation of Rho, Akt phosphorylation, and a decrease in the expression of cyclin-dependent kinase inhibitor 1B (p27kip1). Both Cu2+-oxLDL or LPO-oxLDL significantly increased Akt phosphorylation, whereas an Akt inhibitor, MK2206, blocked oxLDL-induced increase in HAEC proliferation. Blocking Rho with C3 or its downstream target ROCK with Y27632 significantly inhibited oxLDL-induced Akt phosphorylation and proliferation mediated by both Cu2+- and LPO-oxLDL. Activation of RhoA was blocked by Rho-GDI-1, which also abrogated oxLDL-induced Akt phosphorylation and HAEC proliferation. In contrast, blocking Rac1 in these cells had no effect on oxLDL-induced Akt phosphorylation or cell proliferation. Moreover, oxLDL-induced Rho/Akt signaling downregulated cell cycle inhibitor p27kip1. Preloading these cells with cholesterol, however, prevented oxLDL-induced Akt phosphorylation and HAEC proliferation. These findings provide a new understanding of the effects of oxLDL on endothelial proliferation, which is essential for developing new treatments against neovascularization and progression of atherosclerosis.


1983 ◽  
Vol 23 (7) ◽  
pp. 652
Author(s):  
Peter Mucha ◽  
Michael B. Farnell ◽  
Richard S. Bryan

Development ◽  
1995 ◽  
Vol 121 (8) ◽  
pp. 2255-2263 ◽  
Author(s):  
A.M. Murphy ◽  
T. Lee ◽  
C.M. Andrews ◽  
B.Z. Shilo ◽  
D.J. Montell

To investigate the molecular mechanisms responsible for the temporal and spatial control of cell movements during development, we have been studying the migration of a small group of follicle cells, called the border cells, in the Drosophila ovary. Timely initiation of border cell migration requires the product of the slow border cells (slbo) locus, which encodes the Drosophila homolog of the transcription factor C/EBP. Here we report evidence that one target of C/EBP in the control of border cell migration is the FGF receptor homolog encoded by the breathless (btl) locus. btl expression in the ovary was border cell-specific, beginning just prior to the migration, and this expression was reduced in slbo mutants. btl mutations dominantly enhanced the border cell migration defects found in weak slbo alleles. Furthermore, C/EBP-independent btl expression was able to rescue the migration defects of hypomorphic slbo alleles. Purified Drosophila C/EBP bound eight sites in the btl 5′ flanking region by DNAse I footprinting. Taken together these results suggest that btl is a key, direct target for C/EBP in the regulation of border cell migration.


Development ◽  
2001 ◽  
Vol 128 (3) ◽  
pp. 321-330 ◽  
Author(s):  
Y. Liu ◽  
D.J. Montell

Epithelial to mesenchymal transitions and cell migration are important features of embryonic development and tumor metastasis. We are employing a systematic genetic approach to study the border cells in the Drosophila ovary, as a simple model for these cellular behaviors. Previously we found that expression of the basic-region/leucine zipper transcription factor, C/EBP, is required for the border cells to initiate their migration. Here we report the identification of a second nuclear factor, named JING (which means ‘still’), that is required for initiation of border cell migration. The jing locus was identified in a screen for mutations that cause border cell migration defects in mosaic clones. The jing mutant phenotype resembles that of slbo mutations, which disrupt the Drosophila C/EBP gene, but is distinct from other classes of border cell migration mutants. Expression of a jing-lacZ reporter in border cells requires C/EBP. Moreover, expression of jing from a heat-inducible promoter rescues the border cell migration defects of hypomorphic slbo mutants. The JING protein is most closely related to a mouse protein, AEBP2, which was identified on the basis of its ability to bind a small regulatory sequence within the adipocyte AP2 gene to which mammalian C/EBP also binds. We propose that the need to coordinate cell differentiation with nutritional status may be the link between mammalian adipocytes and Drosophila border cells that led to the conservation of C/EBP and AEBP2.


2020 ◽  
Vol 103 (1) ◽  
pp. 24-35
Author(s):  
Rebecca A Holton ◽  
Abigail M Harris ◽  
Barenya Mukerji ◽  
Tanu Singh ◽  
Ferdusy Dia ◽  
...  

Abstract The number and quality of oocytes, as well as the decline in both of these parameters with age, determines reproductive potential in women. However, the underlying mechanisms of this diminution are incompletely understood. Previously, we identified novel roles for CHTF18 (Chromosome Transmission Fidelity Factor 18), a component of the conserved Replication Factor C-like complex, in male fertility and gametogenesis. Currently, we reveal crucial roles for CHTF18 in female meiosis and oocyte development. Chtf18−/− female mice are subfertile and have fewer offspring beginning at 6 months of age. Consistent with age-dependent subfertility, Chtf18−/− ovaries contain fewer follicles at all stages of folliculogenesis than wild type ovaries, but the decreases are more significant at 3 and 6 months of age. By 6 months of age, both primordial and growing ovarian follicle pools are markedly reduced to near depletion. Chromosomal synapsis in Chtf18−/− oocytes is complete, but meiotic recombination is impaired resulting in persistent DNA double-strand breaks, fewer crossovers, and early homolog disjunction during meiosis I. Consistent with poor oocyte quality, the majority of Chtf18−/− oocytes fail to progress to metaphase II following meiotic resumption and a significant percentage of those that do progress are aneuploid. Collectively, our findings indicate critical functions for CHTF18 in ensuring both the quantity and quality of the mammalian oocyte pool.


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