scholarly journals Proximal Tubular Development Is Impaired with Downregulation of MAPK/ERK Signaling, HIF-1α, and Catalase by Hyperoxia Exposure in Neonatal Rats

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Xuewen Xu ◽  
Kai You ◽  
Renge Bu
Keyword(s):  
Cell Apoptosis ◽  
Hypoxia Inducible Factor ◽  
Proximal Tubules ◽  
Mitogen Activated Protein Kinase ◽  
Erk Signaling ◽  
Protective Agent ◽  
Neonatal Rats ◽  
Hyperoxia Exposure ◽  
Proximal Tubular ◽  
Neonatal Hyperoxia

Supplemental oxygen therapy (hyperoxia) is a widely used treatment for alveolar hypoxia in preterm infants. Despite being closely monitored, hyperoxia exposure is believed to undermine neonatal nephrogenesis and renal function caused by elevated oxidative stress. Previous studies have mostly focused on the hyperoxia-induced impairment of glomerular development, while the long-term impact of neonatal hyperoxia on tubular development and the regulatory component involved in this process remain to be clarified. Here, we examined tubular histology and apoptosis, along with the expression profile of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling, hypoxia-inducible factor 1α (HIF-1α), and catalase, following hyperoxia exposure in neonatal rats. Hematoxylin and eosin (H&E) staining revealed the early disappearance of the nephrogenic zone, as well as dilated lumens and reduced epithelial cells, of mature proximal tubules following neonatal hyperoxia. A robust increase in tubular cell apoptosis caused by neonatal hyperoxia was found using a TUNEL assay. Moreover, neonatal hyperoxia altered renal MAPK/ERK signaling activity and downregulated the expression of HIF-1α and catalase in the proximal tubules throughout nephrogenesis from S-shaped bodies to mature proximal tubules. Cell apoptosis in the proximal tubules was positively correlated with HIF-1α expression on the 14th postnatal day. Our data indicates that proximal tubular development is impaired by neonatal hyperoxia, which is accompanied by altered MAPK/ERK signaling as well as downregulated HIF-1α and catalase. Therapeutic management that targets MAPK/ERK signaling, HIF-1α, or catalase may serve as a protective agent against hyperoxia-induced oxidative damage to neonatal proximal tubules.

scholarly journals Vitamin E and lycopene reduce coal burning fluorosis-induced spermatogenic cell apoptosis via oxidative stress-mediated JNK and ERK signaling pathways

2018 ◽  
Vol 38 (4) ◽  
Author(s):  
Yuan Tian ◽  
Yuehai Xiao ◽  
Bolin Wang ◽  
Chao Sun ◽  
Kaifa Tang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Vitamin E ◽  
Protein Kinase ◽  
Cell Apoptosis ◽  
Sperm Count ◽  
Mitogen Activated Protein Kinase ◽  
Spermatogenic Cell ◽  
Erk Signaling ◽  
Male Rat ◽  
Coal Burning

Although fluoride has been widely used in toothpaste, mouthwash, and drinking water to prevent dental caries, the excessive intake of fluoride can cause fluorosis which is associated with dental, skeletal, and soft tissue fluorosis. Recent evidences have drawn the attention to its adverse effects on male reproductive system that include spermatogenesis defect, sperm count loss, and sperm maturation impairment. Fluoride induces oxidative stress through the activation of mitogen activated protein kinase (MAPK) cascade which can lead to cell apoptosis. Vitamin E (VE) and lycopene are two common antioxidants, being protective to reactive oxygen species (ROS)-induced toxic effects. However, whether and how these two antioxidants prevent fluoride-induced spermatogenic cell apoptosis are largely unknown. In the present study, a male rat model for coal burning fluorosis was established and the histological lesions and spermatogenic cell apoptosis in rat testes were observed. The decreased expression of clusterin, a heterodimeric glycoprotein reported to regulate spermatogenic cell apoptosis, was detected in fluoride-treated rat testes. Interestingly, the co-administration with VE or lycopene reduced fluorosis-mediated testicular toxicity and rescued clusterin expression. Further, fluoride caused the enhanced Jun N-terminal kinase (JNK, c-Jun) and extracellular signal-regulated protein kinase (ERK) phosphorylation, which was reduced by VE or lycopene. Thus, VE and lycopene prevent coal burning fluorosis-induced spermatogenic cell apoptosis through the suppression of oxidative stress-mediated JNK and ERK signaling pathway, which could be an alternative therapeutic strategy for the treatment of fluorosis.

scholarly journals Intracellular prostaglandin E2 contributes to hypoxia-induced proximal tubular cell death

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Coral García-Pastor ◽  
Selma Benito-Martínez ◽  
Ricardo J. Bosch ◽  
Ana B. Fernández-Martínez ◽  
Francisco J. Lucio-Cazaña
Keyword(s):  
Hypoxia Inducible Factor ◽  
Renal Diseases ◽  
Prostaglandin E ◽  
Relevant Factor ◽  
Tubular Injury ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Proximal Tubular ◽  
Cox 2 ◽  
Induced Apoptosis

AbstractProximal tubular cells (PTC) are particularly vulnerable to hypoxia-induced apoptosis, a relevant factor for kidney disease. We hypothesized here that PTC death under hypoxia is mediated by cyclo-oxygenase (COX-2)-dependent production of prostaglandin E2 (PGE2), which was confirmed in human proximal tubular HK-2 cells because hypoxia (1% O2)-induced apoptosis (i) was prevented by a COX-2 inhibitor and by antagonists of prostaglandin (EP) receptors and (ii) was associated to an increase in intracellular PGE2 (iPGE2) due to hypoxia-inducible factor-1α-dependent transcriptional up-regulation of COX-2. Apoptosis was also prevented by inhibitors of the prostaglandin uptake transporter PGT, which indicated that iPGE2 contributes to hypoxia-induced apoptosis (on the contrary, hypoxia/reoxygenation-induced PTC death was exclusively due to extracellular PGE2). Thus, iPGE2 is a new actor in the pathogenesis of hypoxia-induced tubular injury and PGT might be a new therapeutic target for the prevention of hypoxia-dependent lesions in renal diseases.

scholarly journals Development of osmotic vacuolization of proximal tubular epithelial cells following treatment with sodium-glucose transport protein 2 inhibitors in type II diabetes mellitus patients-3 case reports

2021 ◽  
Author(s):  
Shun Watanabe ◽  
Naoki Sawa ◽  
Hiroki Mizuno ◽  
Masayuki Yamanouchi ◽  
Tatsuya Suwabe ◽  
...  
Keyword(s):  
Serum Creatinine ◽  
Type Ii Diabetes ◽  
Sglt2 Inhibitor ◽  
Type Ii Diabetes Mellitus ◽  
Proximal Tubules ◽  
Type Ii ◽  
Tubular Epithelial Cells ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Standard Weight

AbstractWe encountered 3 cases of acute kidney injury that occurred after treatment with a SGLT2 inhibitor. In case 1, serum creatinine increased from 1.65 to 3.0 mg/dL, in case 2, serum creatinine increased from 1.03 to 1.21 mg/dL, and in case 3, serum creatinine increased from 0.8 to 1.1 mg/dL. Renal biopsy showed isometric vacuolization on tubules, that was completely negative for Periodic acid-Schiff (PAS) stain in case 1, and was partially negative for PAS stain in case 2 and 3, consistent with osmotic vacuolization. Immunohistochemical analysis showed positive staining for CD138 and CD10 indicating the proximal tubules in the vacuolar lesions. 3 patients were obese with body mass index of more than 30, and showed an increase in serum renin. In conclusion, in type II diabetes mellitus (T2DM), individuals that remain within their standard weight range, SGLT2 inhibitor treatment does not result in osmotic vacuolization of proximal tubular epithelial cells and AKI. However, treatment with a SGLT2 inhibitor may cause damage of the proximal tubules resulting in AKI in T2DM individuals who do not remain within their standard weight range, due to an overdose lavage of sugar in the urine and dehydration.

RNA viruses and the mitogenic Raf/MEK/ERK signal transduction cascade

2008 ◽  
Vol 389 (10) ◽  
Author(s):  
Stephan Pleschka
Keyword(s):  
Signal Transduction ◽  
Rna Viruses ◽  
Rna Virus ◽  
Cell Metabolism ◽  
Mitogen Activated Protein Kinase ◽  
Erk Signaling ◽  
Control Center ◽  
Signal Transduction Cascade ◽  
Host Interaction ◽  
Differentiation And Proliferation

AbstractThe Raf/MEK/ERK signal transduction cascade belongs to the mitogen-activated protein kinase (MAPK) cascades. Raf/MEK/ERK signaling leads to stimulus-specific changes in gene expression, alterations in cell metabolism or induction of programmed cell death (apoptosis), and thus controls cell differentiation and proliferation. It is induced by extracellular agents, including pathogens such as RNA viruses. Many DNA viruses are known to induce cellular signaling via this pathway. As these pathogens partly use the DNA synthesis machinery for their replication, they aim to drive cells into a proliferative state. In contrast, the consequences of RNA virus-induced Raf/MEK/ERK signaling were less clear for a long time, but since the turn of the century the number of publications on this topic has rapidly increased. Research on this virus/host-interaction will broaden our understanding of its relevance in viral replication. This important control center of cellular responses is differently employed to support the replication of several important human pathogenic RNA viruses including influenza, Ebola, hepatitis C and SARS corona viruses.

Carbohydrate metabolism by primary cultures of rabbit proximal tubules

1989 ◽  
Vol 256 (3) ◽  
pp. C532-C539 ◽  
Author(s):  
M. J. Tang ◽  
K. R. Suresh ◽  
R. L. Tannen
Keyword(s):  
Pyruvate Kinase ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Cultured Cells ◽  
Primary Cultures ◽  
Lactate Production ◽  
Proximal Tubules ◽  
Glycolytic Metabolism ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Proximal Tubular

Renal proximal tubular epithelia were used to assess the factors responsible for the induction of glycolysis in cultured cells. Primary cultures of rabbit proximal tubules, which achieved confluency at 6 days, exhibited hormonal responsiveness and brush-border characteristics typical of proximal tubular cells. Beginning at day 4, these cultured cells exhibited increased glycolytic metabolism reflected by enhanced glucose uptake and lactate production, along with parallel increases in activity of the glycolytic enzymes, pyruvate kinase and lactate dehydrogenase. The gluconeogenic enzymes, phosphoenolpyruvate carboxykinase (PEPCK) and fructose-1,6-bisphosphatase (FDP), were downregulated, and the cultured cells exhibited lower oxygen consumption rates than fresh tubules. Cells grown on a rocker, to mitigate hypoxia, exhibited a metabolic and enzymatic profile similar to cells grown under still conditions. ATP levels in cultured cells were higher than in fresh tubules. Furthermore, pyruvate kinase activity was higher in cells grown in media containing 0.5 as contrasted with 25 mM glucose. The enhanced glycolytic metabolism exhibited by cultured proximal tubular cells appears to be a characteristic of proliferation and is not a response to hypoxia, the Pasteur effect, or environmental glucose.

Isolation of a pure suspension of rat proximal tubules

1981 ◽  
Vol 241 (4) ◽  
pp. F403-F411 ◽  
Author(s):  
P. Vinay ◽  
A. Gougoux ◽  
G. Lemieux
Keyword(s):  
Phosphoenolpyruvate Carboxykinase ◽  
Periodic Acid ◽  
Vital Staining ◽  
Staining Technique ◽  
Proximal Tubules ◽  
Periodic Acid Schiff ◽  
Homogeneous Population ◽  
Proximal Tubular ◽  
Percoll Density Gradient ◽  
Enzyme Location

A suspension of cortical tissue fragments prepared by collagenase digestion of renal cortex obtained from fed and chronically acidotic (NH4Cl) rats was separated into four bands on a Percoll density gradient. By microscopic examination, vital staining with trypan blue, and histologic staining technique (periodic acid-Schiff) the F4 band was shown to contain only (greater than 98%) proximal tubules, whereas the F1 band was significantly enriched (70%) with distal tubules contaminated by glomeruli and short segments of proximal tubules. Intra/extracellular ratios for PAH of 15 were measured in the F4 band and of 2 in F1 band. ATP was 1.4 and 2.8 mumol/g in the F4 and F1 bands, respectively, and was stable for at least 60 min. The proximal F4 band was shown to be gluconeogenic (L-glutamine or L-lactate 2.5 mM as substrate) and to adapt to metabolic acidosis. The distal F1 band was shown to be glycolytic (glucose 2.5 mM) with no changes with acid-base status. All fractions were shown to metabolize glutamine, but the metabolic fate of this amino acid was different in proximal and distal structures. A F4/F1 activity ratio for the proximal cytoplasmic phosphoenolpyruvate carboxykinase enzyme of 2.6 and 4.3 was observed in normal and acidotic rats, respectively. In contrast, a F4/F1 ratio of 0.13 and 0.22 was observed for the distal cytoplasmic hexokinase enzyme. This preparation, therefore, allows the metabolism of a homogeneous population of proximal tubular fragments to be studied and can be used to obtain information on enzyme location within the nephron.

scholarly journals Probiotic-Derived Polyphosphate Accelerates Intestinal Epithelia Wound Healing through Inducing Platelet-Derived Mediators

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Shotaro Isozaki ◽  
Hiroaki Konishi ◽  
Mikihiro Fujiya ◽  
Hiroki Tanaka ◽  
Yuki Murakami ◽  
...  
Keyword(s):  
Wound Healing ◽  
Cell Growth ◽  
Epithelial Cell ◽  
Intestinal Inflammation ◽  
Light Transmission ◽  
Platelet Rich Plasma ◽  
Mitogen Activated Protein Kinase ◽  
Erk Signaling ◽  
Intestinal Barrier Function ◽  
Ki 67

Inflammatory bowel disease (IBD), such as ulcerative colitis (UC) and Crohn’s disease (CD), is an intractable intestinal inflammation associated with the disruption of the intestinal mucosa. We previously demonstrated that Lactobacillus brevis-derived long-chain polyphosphate (poly P) improved the intestinal barrier function by the upregulation of cell adhesion and relieved intestinal inflammation, thereby exerting a curing effect on colitis in vitro, in vivo, and in an investigator-initiated clinical study of UC. However, how poly P improves mucosal defects induced by intestinal inflammation has not been elucidated. In this study, we detected the accumulation of platelets in inflamed tissues induced by poly P in a dextran sulfate sodium- (DSS-) induced colitis mouse model. A light transmission aggregometry analysis and scanning electron microscopy showed that poly P promoted the platelet aggregation. An SRB assay and ki-67 staining showed that the supernatant of poly P-treated platelet-rich plasma (PRP) increased intestinal epithelial cell growth. A wound healing assay showed that the supernatant of poly P-treated PRP, but not poly P itself, accelerated wound healing. A Western blotting analysis indicated that mitogen-activated protein kinase activation was induced by the supernatant of poly P-treated human PRP in the epithelial cells and its wound healing effect was significantly decreased by the inhibition of ERK signaling. These data suggested that platelet-derived mediators induced by poly P improved intestinal inflammation through the promotion of epithelial cell growth by the activation of the ERK signaling pathway. The mechanism is a novel host-microbe interaction through mammalian platelet-derived mediators induced by bacterial molecules.

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