Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of oxidative stress in mercuric chloride (HgCl2)-induced nephrotoxicity is uncertain and controversial. We demonstrate that I.L.C-PK1 cells, exposed to HgCl2, generate massive amounts of hydrogen peroxide, the latter completely quenched by the hydrogen peroxide scavenger, pyruvate. HgCl2 exerts a dose-dependent cytotoxicity which is attenuated by pyruvate and catalase. Cellular generation of hydrogen peroxide arises, at least in part, from mitochondria since mitochondrial rates of generation of hydrogen peroxide increase in response to HgCl2; HgCl2 also provokes a shift in absorbance spectra in rhodamine 123 loaded-mitochondria and stimulates mitochondrial state 4 respiration. HgCl2, applied for one hour, impairs cellular vitality as demonstrated by the MTT assay, an assay dependent in part on mitochondrial function. HgCl2 impairs function in other organelles such as lysosomes that maintain a transmembrane proton gradient; these latter effects are partially attenuated by pyruvate. We complement these in vitro findings with in vivo evidence demonstrating that HgCl2 stimulates renal generation of hydrogen peroxide. The functional significance of such generation of hydrogen peroxide was evaluated in rats deficient in selenium and vitamin E, a nutrient deficiency that impairs the scavenging of hydrogen peroxide and promotes the toxicity of this oxidant. In these rats serum creatinine values were significantly higher on sequential days following the administration of HgCl2. To probe the renal response to oxidative stress induced by HgCl2, we examined hydrogen peroxide-scavenging enzymes and redox-sensitive genes. Catalase activity was unaltered whereas glutathione peroxidase activity was decreased, effects that may contribute to the net renal generation of hydrogen peroxide. The redox sensitive enzyme, heme oxygenase, was markedly up-regulated in the kidney in response to HgCl2. HgCl2 also induced members of the bcl family, bcl2 and bclx, genes that protect against apoptosis and oxidant injury. In another model of oxidant-induced renal injury, the glycerol model, bcl2 mRNA was not induced at 6 and 24 hours after the administration of glycerol. In summary, we demonstrate that HgCl2 potently stimulates renal generation of hydrogen peroxide in vitro and in vivo and such generation of peroxide contributes to renal dysfunction in vitro and in vivo. We also demonstrate that in response to HgCl2, redox sensitive genes are expressed including heme oxygenase and members of the bcl family.
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PMID:Renal oxidant injury and oxidant response induced by mercury. 887 81

In this study, we attempted to investigate the response of polarized cells to inappropriate interaction with the extracellular matrix. Cell lines of epithelial [Madin-Darby canine kidney (MDCK) and LLC-PK1], endothelial [bovine aortic endothelial cells (BAEC)], and mesenchymal (ESK-4 and NIH/3T3) origins were employed. With collagen gel overlay, MDCK cells underwent membrane remodeling and gradually developed lumen formation within 24 h. Apoptosis could also be observed following cell remodeling. The ratio of apoptosis was enhanced from 12.1 +/- 2.4% within 24 h to 58.4 +/- 9.8% at day 3, and finally the monolayer was disintegrated. Collagen gel overlay-induced apoptosis was not a result of physical stress, since agarose gel overlay did not induce any morphological alterations. All epithelial and endothelial cells examined developed apoptosis in response to collagen overlay. In contrast, collagen overlay did not affect growth of fibroblasts at all, although their growth under agarose gel was slightly hindered due to physical stress. Collagen overlay-induced apoptosis seems to be a unique phenomenon for polarized cells and thus is defined as "disoriented cell death." Furthermore, anti-alpha2-integrin antibody could abolish collagen overlay-induced morphological changes and apoptosis in MDCK cells, indicating that signals through alpha2-integrin on the apical membrane are required for disoriented cell death. Finally, Bcl-2 overexpression prolonged survival of MDCK cells in response to collagen overlay, but these cells eventually developed apoptosis due to downregulation of Bcl-2 protein. These findings indicate that inappropriate cell-matrix interaction results in apoptosis, which may account for cell death mechanisms during developmental processes or under pathological conditions.
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PMID:Collagen gel overlay induces apoptosis of polarized cells in cultures: disoriented cell death. 975 45

In primary cultures of porcine proximal tubular kidney cells and LLC-PK1 cells cisplatin (5 - 50 microM) caused apoptosis and cell detachment; in both systems cell detachment occurred, preceded by a loss of cytoskeletal F-actin stress fibers within 4 - 6 h, and a reduction of mRNA encoding for fibronectin, collagen a2 type (IV) and laminin B2 within 17 - 41 h. Prevention of F-actin damage by phalloidin prevented nuclear fragmentation, suggesting a relation between F-actin damage and apoptosis. Overexpression of Bcl-2 also prevented apoptosis, but did not prevent damage to the F-actin skeleton or the reduction of mRNA expression of the matrix proteins. These results suggest that Bcl-2 overexpression interferes with apoptotic signals downstream of F-actin. The relevance of these results for cell detachment in kidney toxicity is discussed.
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PMID:Cisplatin effects on F-actin and matrix proteins precede renal tubular cell detachment and apoptosis in vitro. 1020 May 15

The nephrotoxicity of trichloroethylene and dichloroacetylene has previously been linked to mitochondrial dysfunction induced by the metabolite S-(1,2-dichlorovinyl)-l-cysteine (DCVC). In this study, we examined whether key biochemical steps associated with mitochondria occur in DCVC-induced apoptosis in cultured porcine proximal tubular LLC-PK1 cells. DCVC caused a decrease in mitochondrial membrane potential (mt Delta Psi) beginning at 4 h and a release of cytochrome c into the cytoplasm at 6 h. Caspase-3-like activity was detected at 6 h and extensive DNA fragmentation was observed at 8 h. Decreases in cellular ATP were not evident until 8 h and later, even though electron microscopy showed that the mitochondria were extensively swollen. Aminooxyacetic acid (AOAA), an inhibitor of cysteine-conjugate beta-lyase, protected against mitochondrial changes and apoptosis. Overexpression of the antiapoptotic Bcl-2 protein desensitized LLC-PK1 cells to DCVC-induced apoptosis. These results support the interpretation that mitochondrial release of cyt c and cyt c-dependent activation of caspase-3 could have a central role in nephrotoxicity due to haloalkene-derived cysteine S-conjugates.
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PMID:Role of mitochondrial dysfunction in S-(1,2-dichlorovinyl)-l-cysteine-induced apoptosis. 1116 82

Bcl-2 protein family members are among the key regulators of the apoptosis effector phase. Therefore, we investigated the ability of synthetic peptides derived from proteins of the Bcl-2 family, namely, the NH2-terminal region of Bcl-2 (Bcl2_syn), a central domain of Bax (Bax_syn), and a central domain of Bak (Bak_syn) to interfere with the apoptotic process in LLC-PK1 cells. Apoptosis was induced by tacrolimus or lipopolysaccharide treatment, and microinjection of Bcl2_syn into stimulated LLC-PK1 cells significantly reduced the percentage of apoptotic cells detected within 4 h after the treatment. Microinjection of Bax_syn or Bax_syn, in contrast, induced apoptosis in otherwise untreated LLC-PK1 cells during the same period of time. A random sequence control peptide (Control_syn), which served as a negative control, as well as FITC-labeled dextran, which was coinjected in all experiments for visualization, were ineffective in either preventing or inducing apoptosis. These results suggest that synthetic peptides mimicking the functional domains of proteins of the Bcl-2 family are capable of regulating apoptosis when microinjected into LLC-PK1 cells in vivo. Analogs to these regulatory peptides could therefore provide valuable lead compounds in the therapeutical context.
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PMID:Effects of microinjection of synthetic Bcl-2 domain peptides on apoptosis of renal tubular epithelial cells. 1206 Jun 1

The addition of tumor necrosis factor (TNF)-alpha into the cultured porcine kidney LLC-PK1 cells caused apoptosis concomitantly with caspase-3 activation and the inductions of an endogenous Bcl-2 protein. An SDS-polyacrylamide electrophoretic analysis revealed that a 37-kDa protein in a nuclear fraction was increased during TNF-alpha-induced apoptosis. Partial amino acid sequence of the protein was A-L-T-G-H-L-E-E-V, perfectly matching that of annexin I. Immunocytochemistry revealed that annexin I migrated to the nucleus and/or peri-nucleus region upon exposure to TNF-alpha. Overexpression of Bcl-2 proteins inhibited the nuclear localization of annexin I during TNF-alpha-induced apoptosis. Antisense oligodeoxynucleotides complementary to annexin I-inhibited TUNEL (terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labelling) staining in TNF-alpha-treated cells, suggesting that annexin I expression is a possible prerequisite for the induction of apoptosis by the cytokine. Thus, it is first time to show that annexin I is regulated by an anti-apoptotic Bcl-2 protein in TNF-alpha-induced renal apoptotic events.
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PMID:Overexpression of Bcl-2 inhibits nuclear localization of annexin I during tumor necrosis factor-alpha-mediated apoptosis in porcine renal LLC-PK1 cells. 1554 40

We reported previously that radiocontrast medium induces caspase-dependent apoptosis and that cAMP analogs inhibit cell injury in cultured renal tubular cells. In the present study, cellular mechanisms underlying the protective effects of cAMP were determined. Ioversol, a radiocontrast medium, caused cell injury accompanied by decreases in Bcl-2, increases in Bax, and caspase activation in LLC-PK1 cells. Both cell injury and cellular events induced by ioversol were inhibited by dibutyryl cAMP and the prostacyclin analog beraprost. Dibutyryl cAMP increased phosphorylation of Akt and CREB, both of which were reversed by H89, wortmannin and the Akt inhibitor SH-6. The protective effect of dibutyryl cAMP was also reversed by these kinase inhibitors. In dominant-negative CREB-transfected cells, dibutyryl cAMP no longer prevented cell injury or inhibited changes in mRNA expression of Bcl-2 and Bax. In mice with unilateral renal occlusion, ioversol increased urinary excretion of N-acetyl-beta-d-glucosaminidase with concomitant decreases in Bcl-2 mRNA, increases in Bax mRNA, activation of caspase-3, and induction of apoptosis in tubular and interstitial cells. Beraprost completely reversed these in vivo effects of ioversol. These findings suggest that elevation of endogenous cAMP effectively prevents radiocontrast nephropathy through activation of A kinase/PI 3-kinase/Akt followed by CREB phosphorylation and enhanced expression of Bcl-2.
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PMID:A prostacyclin analog prevents radiocontrast nephropathy via phosphorylation of cyclic AMP response element binding protein. 1585 35

Nephrotoxicity is common with the use of the chemotherapeutic agent cisplatin, but the cellular mechanisms that modulate the extent of injury are unknown. Cisplatin downregulates expression of the taurine transporter gene (TauT) in LLC-PK1 proximal tubular renal cells, and forced overexpression of TauT protects against cisplatin-induced apoptosis in vitro. Because the S3 segments of proximal tubules are the sites of both cisplatin-induced injury and adaptive regulation of the taurine transporter, we hypothesized that TauT functions as an anti-apoptotic gene and protects renal cells from cisplatin-induced nephrotoxicity in vivo. Here, we studied the regulation of TauT in cisplatin nephrotoxicity in a human embryonic kidney cell line and in LLC-PK1 cells, as well as in TauT transgenic mice. Cisplatin-induced activation of p53 repressed TauT and overexpression of TauT prevented the progression of cisplatin-induced apoptosis and renal dysfunction in TauT transgenic mice. Although cisplatin activated p53 and PUMA (a p53-responsive proapoptotic Bcl-2 family protein) in the kidneys of both wildtype and TauT transgenic mice, only wildtype animals demonstrated acute kidney injury. These data suggest that functional TauT plays a critical role in protecting against cisplatin-induced nephrotoxicity, possibly by attenuating a p53-dependent pathway.
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PMID:Functional TauT protects against acute kidney injury. 1942 93

Lithium, a prophylactic drug for the treatment of bipolar disorder, is prescribed with caution due to its side effects, including renal damage. In this study porcine LLC-PK1 renal tubular cells were used to establish the direct toxicity of lithium on proximal cells and gain insights into the molecular mechanisms involved. In the presence of LiCl, cell proliferation exhibited insignificant decreases in a concentration-dependent manner, but once confluent, constant cell numbers were observed. Cell cycle studies indicated a small dose-dependent accumulation of cells in the G2/M stage after 24 h, as well as an increase in cells in the G0/G1 phase after treatment with 1-10 mM LiCl, but not at 20 mM LiCl. No evidence of apoptosis was observed based on cell morphology or DNA fragmentation studies, or evidence of protein expression changes for Bax, Bcl-2, and p53 proteins using immunocytochemistry. In addition caspases 3, 8 and 9 activity remained unaltered between control and lithium-treated cultures. To conclude, exposure to high concentrations of lithium did not result in overt toxic effects to LLC-PK1 renal cells, although LiCl did alter some aspects of cell behaviour, which could potentially influence function over time.
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PMID:Porcine proximal tubular cells (LLC-PK1) are able to tolerate high levels of lithium chloride in vitro: assessment of the influence of 1-20 mM LiCl on cell death and alterations in cell biology and biochemistry. 1994 24

Cordyceps Sobolifera (CS), an economic traditional Chinese herb, may ameliorate nephrotoxicity-induced renal dysfunction in the rat via antioxidant, anti-apoptosis, and anti-autophagy mechanisms. We investigated the water extract of fermented whole broth of CS on lipopolysaccharide (LPS)-induced renal cell injury in vitro and in vivo. CS effect on LPS-induced epithelial Lilly pork kidney (PK1) and Madin-Darby canine kidney epithelial (MDCK) cell death was detected with MTT assay. Two-month treatment of CS effects on renal blood flow (RBF), glomerular filtration rate (GFR), plasma blood urea nitrogen, creatinine level and leukocytes (WBC) count were determined in the LPS-treated rats. We further examined the effects of CS supplement on renal tubular oxidative stress, endoplasmic reticulum stress, apoptosis and autophagy by Western blot analysis. LPS dose-dependently induced PK1 and MDCK cell death, which can be ameliorated by CS treatment. LPS significantly decreased RBF and GFR and increased blood leukocyte counts, plasma blood urea nitrogen and creatinine level in the rat after 24 hours of injury. LPS enhanced renal tubular ER stress, autophagy and apoptosis via by increase protein expressions of GRP78, caspase 12, Beclin-1 and Bax/Bcl-2 ratio. These findings are associated with the significant staining in renal proximal and distal tubular ED-1, GRP78, Beclin-1 autophagy, and TUNEL apoptosis in the LPS-treated kidneys. Two months of CS supplement significantly improved RBF, GFR and WBC values and reduced ED-1, GRP78, Beclin-1 autophagy and TUNEL apoptosis in the LPS-treated kidneys. Long-term CS treatment reduced LPS-induced stress responses and tissue damage possibly via blocking LPS-triggered signaling pathways.
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PMID:Cordyceps sobolifera extract ameliorates lipopolysaccharide-induced renal dysfunction in the rat. 2159 19


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