Calcium dependence of integrity of the actin cytoskeleton of proximal tubule cell microvilli

Sogabe, Keizo; Roeser, Nancy F.; Davis, Julie; Nurko, Saul; Venkatachalam, Manjeri A.; Weinberg, Joel M.

doi:10.1152/ajprenal.1996.271.2.f292

Cited by 19 publications

(34 citation statements)

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“…morphological changes and membrane permeabilising activity) induced by diC14-amidine are related. The disturbance in membrane integrity may induce an elevation of the Ca 2+ level in the cytosol, which was shown by others to cause actin filament disassembly [27]. Observation of the morphology of the actin cytoskeleton (with TRITC-phalloidin) showed neither the changes related to the membrane morphology nor visible changes in actin filament density (data not shown).…”

Section: Resultsmentioning

confidence: 81%

Higly fusogenic cationic liposomes transiently permeabilize the plasma membrane of HeLa cells

Stebelska

Wyrozumska

Gubernator³

et al. 2007

Cellular and Molecular Biology Letters

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Cationic liposomes can efficiently carry nucleic acids into mammalian cells. This property is tightly connected with their ability to fuse with negatively charged natural membranes (i.e. the plasma membrane and endosomal membrane). We used FRET to monitor and compare the efficiency of lipid mixing of two liposomal preparations -one of short-chained diC14-amidine and one of long-chained unsaturated DOTAP -with the plasma membrane of HeLa cells. The diC14-amidine liposomes displayed a much higher susceptibility to lipid mixing with the target membranes. They disrupted the membrane integrity of the HeLa cells, as detected using the propidium iodide permeabilization test. Morphological changes were transient and essentially did not affect the viability of the HeLa cells. The diC14-amidine liposomes were much more effective at either inducing lipid mixing or facilitating transfection.

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Section: Resultsmentioning

confidence: 81%

Higly fusogenic cationic liposomes transiently permeabilize the plasma membrane of HeLa cells

Stebelska

Wyrozumska

Gubernator³

et al. 2007

Cellular and Molecular Biology Letters

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“…[31][32][33] Without extra protective substrates during hypoxia or reoxygenation, the majority of tubules showed little or no recovery at the end of reoxygenation (Figure 3e). With addition of ␣KG/ASP during reoxygenation, most tubules recovered a normal appearance of F-actin and fodrin (Figure 3f).…”

Section: Resultsmentioning

confidence: 99%

“…28,32,33 Tubules were suspended at 3.0 to 5.0 mg of tubule protein/ml in a 95% O 2 /5% CO 2 5.0 sodium butyrate, 3% dialyzed dextran (T-40, Pharmacia), and 2 glycine. Medium A was also supplemented with 0.5 mg/ml of bovine gelatin (75 bloom) to suppress aggregation of the isolated tubules during the prolonged experimental incubation periods.…”

Section: Isolation Of Tubulesmentioning

confidence: 99%

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Energetic Determinants of Tyrosine Phosphorylation of Focal Adhesion Proteins during Hypoxia/Reoxygenation of Kidney Proximal Tubules

Weinberg¹,

Venkatachalam²,

Roeser³

et al. 2001

The American Journal of Pathology

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Anaerobic mitochondrial metabolism of ␣-ketoglutarate and aspartate or ␣-ketoglutarate and malate can prevent and reverse severe mitochondrial dysfunction during reoxygenation after 60 minutes of hypoxia in kidney proximal tubules. 34 The present studies demonstrate that, during hypoxia, paxillin, focal adhesion kinase, and p130 cas migrated faster by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, their phosphotyrosine (pY) content decreased to ϳ5% of that in oxygenated tubules without changes in total protein, and the normally basal immunostaining of ␤1 and ␣6 integrin subunits, pY, and paxillin was lost or markedly decreased. During reoxygenation without supplemental substrates, recovery of pY and basal localization of the focal adhesion proteins was poor. ␣-Ketoglutarate and aspartate, which maintained slightly higher levels of ATP during hypoxia, also maintained 2.5-fold higher levels of pY during this period, and promoted full recovery of pY content and basal localization of focal adhesion proteins during subsequent reoxygenation. Similarly complete recovery was made possible by provision of ␣-ketoglutarate and aspartate or ␣-ketoglutarate and malate only during reoxygenation. These data emphasize the importance of very low energy thresholds for maintaining the integrity of key structural and biochemical components required for cellular survival and reaffirm the value of approaches aimed at conserving or generating energy in cells injured by hypoxia or ischemia. Ischemic and related forms of acute renal failure result from a complex interplay of vascular and tubular events that can vary in their relative contributions depending on characteristics of the specific clinical situation or experimental model. Although the process is frequently also termed acute tubular necrosis, much of the tubule cell damage in both animal models and human acute renal failure is sublethal and reversible within affected cells. [1][2][3][4][5][6] Effects on multiple subcellular structures have been described including loss of brush border microvilli and simplification of the basolateral membrane, 1-3 disruption of the normal polar distribution of major membrane-associated proteins including Na ϩ ,K ϩ -ATPase and its associated cytoskeletal proteins, 7,8 disruption of tight junctions and adherens junctions, 5,9 -13 and abnormalities of integrin distribution and function, 14 -19 all of which can contribute to impaired barrier function and vectorial transport by the epithelium. ATP depletion and the resulting protein dephosphorylation 10 -13,20,21 are the primary processes initiating these events.Proximal tubules have relatively little or no glycolytic capacity making them dependent on mitochondrial metabolism for ATP synthesis. 22,23 Freshly isolated proximal tubules rapidly develop lethal damage when subjected to hypoxia or other ATP-depleting maneuvers, 24 -27 which has limited their utility for studying reversible structural and metabolic alterations. This situation has improved with recognition that much of their se...

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“…Several studies have demonstrated that ischemic changes lead to ATP depletion and cause cytoskeletal alterations. 31,32,[34][35][36] Thus, both a direct action of the venom and an indirect ischemic mechanism may induce morphologic and functional renal alterations. Ischemia has been associated with changes in arterial pressure and the deposition of fibrin thrombi in renal capillaries, neither of which was observed with B. moojeni venom.…”

Section: Discussionmentioning

confidence: 99%

Histologic and functional renal alterations caused by Bothrops moojeni snake venom in rats.

Bôer¹,

Gontijo²,

Cruz‐Höfling³

1999

The American Journal of Tropical Medicine and Hygiene

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Abstract. Acute renal failure (ARF) is the main cause of death following snake bites by Bothrops species. In this study, we investigated the morphologic and functional renal disturbances caused by Bothrops moojeni venom in rats. Renal function was assessed based on creatinine and lithium clearances and on histologic examination of renal tissue 5 hr after the intravenous administration of 0.2 mg of venom/kg and 5 hr, 16 hr, and 48 hr after 0.4 mg of venom/ kg. A venom dose of 0.4 mg/kg produced renal tubule disturbances, including acute impairment of proximal and post-proximal tubule sodium handling associated with acute tubule necrosis. The glomerular filtration rate (GFR) decreased significantly and was accompanied by severe morphologic disturbances in the renal glomeruli. These functional and morphologic findings were observed in the absence of any change in mean arterial blood pressure. The decrease in GFR was not related to the presence of fibrin deposits in the glomerular capillary loops. These results suggest an early nephrotoxic action of B. moojeni venom involving significant morphologic and functional changes similar to those observed in snakebite-induced ARF in humans. Envenomation following snakebite is a health problem in tropical regions of the world. The genus Bothrops contains many species distributed from Mexico to Argentina. 1 Of the 20,000 snakebite accidents per year in Brazil, about 90% are attributed to the genus Bothrops. 2 Bothrops moojeni is the most common cause of snakebite in central Brazil (Cardoso JLC, unpublished data). In common with other Bothrops venoms, 3-7 B. moojeni venom contains blood-clotting, hemorrhagic, phospholipase A 2 , and proteolytic activities. 8 Envenomation by Bothrops species leads to local and systemic effects that develop simultaneously. The local lesions include edema, pain, erythema, ecchymosis, bullae, cyanosis, necrosis, and cellulitis. The most serious systemic change and primary cause of death is acute renal failure (ARF) secondary to acute tubular necrosis and, occasionally, glomerulonephritis. 3,4,7,[9][10][11][12][13][14] Thus, elucidation of the mechanisms involved in this nephrotoxicity is important. Experimental models used to investigate the pathogenesis of renal lesions caused by bothropic venoms have shown hemodynamic changes and hemolysis prior to renal ischemia. 4,6,15 Ischemia caused by massive fibrin deposition in the glomerular capillaries as well as intravascular hemolysis appear to have a crucial role in the physiopathology of renal failure. 16 However a direct nephrotoxic action of the venom cannot be excluded.In this work, we studied the pathogenesis of the alterations in renal function and morphology in rats after a single intravenous injection of B. moojeni venom. Experimental protocol. One group of rats was injected with venom (V 1 ) and another, which served as the control group, received 0.15 M NaCl solution (S 1 ). The renal function of both groups was evaluated 5 hr (V, n ϭ 7; S, n ϭ 5), 16 hr (V, n ϭ 6; S, n ϭ 4), and 48 hr (V,...

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Calcium dependence of integrity of the actin cytoskeleton of proximal tubule cell microvilli

Cited by 19 publications

References 0 publications

Higly fusogenic cationic liposomes transiently permeabilize the plasma membrane of HeLa cells

Higly fusogenic cationic liposomes transiently permeabilize the plasma membrane of HeLa cells

Energetic Determinants of Tyrosine Phosphorylation of Focal Adhesion Proteins during Hypoxia/Reoxygenation of Kidney Proximal Tubules

Histologic and functional renal alterations caused by Bothrops moojeni snake venom in rats.

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