Improved culture conditions stimulate gluconeogenesis in primary cultures of renal proximal tubule cells

Nowak, Grażyna; Schnellmann, Rick G.

doi:10.1152/ajpcell.1995.268.4.c1053

Cited by 91 publications

(83 citation statements)

References 17 publications

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“…It is not conclusive that glycolytic enzyme activity changes that are measured in the whole cortex are in the proximal tubules; however, the possibility of such notion was raised by in vitro observation. In primary cultures of proximal tubular cells, the activities of key enzymes of gluconeogenic pathway decrease, together with an increase in the rate of glycolysis and glycolytic enzyme activities (38,39). Therefore, the use of HK2 cells in culture may be an appropriate and representative model for DN in vivo.…”

Section: Discussionmentioning

confidence: 99%

Therapeutic Approach for Diabetic Nephropathy Using Gene Delivery of Translocase of Inner Mitochondrial Membrane 44 by Reducing Mitochondrial Superoxide Production

Zhang¹,

Wada²,

Hashimoto³

et al. 2006

Journal of the American Society of Nephrology

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Hyperglycemia-induced overproduction of mitochondrial reactive oxygen species has emerged as a major player in diabetic vascular complications. Mammalian translocase of inner mitochondrial membrane 44 (TIM44) was identified by upregulation in diabetic mouse kidneys. TIM44 functions as a membrane anchor of mitochondrial heat-shock protein 70 (mtHsp70) to TIM23 complex and is involved in the import of mitochondria-targeted preproteins into mitochondrial matrix. The process is dependent on inner membrane potential and ATP hydrolysis on ATPase domain of mitochondrial heat-shock protein 70. Hemagglutination virus of Japan-envelope vector that carries pcDNA3.1 plasmid that contains the full-length cDNA of TIM44 and control plasmid were injected weekly into the tail vein of uninephrectomized streptozotocin-induced diabetic CD-1 mice. The gene delivery alleviated proteinuria and renal hypertrophy at 8 wk after the injection, inhibited renal cell proliferation and apoptosis, and suppressed superoxide production. In vitro experiments, using human proximal tubular (HK2) cells, revealed that the gene delivery of TIM44 reversed high glucose-induced metabolic and cellular abnormalities such as enhanced reactive oxygen species production, increased ATP contents, alterations in inner membrane potential, increased cell proliferation, and apoptosis. Transfection with siRNA and expressing vector of TIM44 revealed that TIM44 facilitates import of antioxidative enzymes such as superoxide dismutase and glutathione peroxidase into mitochondria. The gene delivery of TIM44 therefore seems to be beneficial for the maintenance of mitochondrial function and is a novel therapeutic approach for diabetic nephropathy.

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Section: Discussionmentioning

confidence: 99%

Therapeutic Approach for Diabetic Nephropathy Using Gene Delivery of Translocase of Inner Mitochondrial Membrane 44 by Reducing Mitochondrial Superoxide Production

Zhang¹,

Wada²,

Hashimoto³

et al. 2006

Journal of the American Society of Nephrology

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“…oxygen (9)(10)(11)(12)(13)(14)(15); (2) exposure to 1% O 2 /5% CO 2 (balance consisting of N 2 ) in a tightly sealed modular incubator chamber (Billups-Rothenberg, Del Mar, CA) for 24 to 48 hours at 378C; (3) treatment with dimethyloxalylglycine (DMOG) to specifically block prolyl hydroxylation, and therefore lead to HIF-1a accumulation; (4) treatment with cobalt chloride (CoCl 2 ), a hypoxia mimetic; and (5) combinations of the above conditions as a means of testing for additive or synergistic effects. The cells were incubated in media containing 3% FBS for a minimum of 24 hours before each experiment.…”

Section: Clinical Relevancementioning

confidence: 99%

Role of Oxygen Availability in CFTR Expression and Function

Guimbellot¹,

Fortenberry²,

Siegal³

et al. 2008

Am J Respir Cell Mol Biol

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The cystic fibrosis transmembrane conductance regulator (CFTR) serves a pivotal role in normal epithelial homeostasis; its absence leads to destruction of exocrine tissues, including those of the gastrointestinal tract and lung. Acute regulation of CFTR protein in response to environmental stimuli occurs at several levels (e.g., ion channel phosphorylation, ATP hydrolysis, apical membrane recycling). However, less information is available concerning the regulatory pathways that control levels of CFTR mRNA. In the present study, we investigated regulation of CFTR mRNA during oxygen restriction, examined effects of hypoxic signaling on chloride transport across cell monolayers, and related these findings to a possible role in the pathogenesis of chronic hypoxic lung disease. CFTR mRNA, protein, and function were robustly and reversibly altered in human cells in relation to hypoxia. In mice subjected to low oxygen in vivo, CFTR mRNA expression in airways, gastrointestinal tissues, and liver was repressed. CFTR mRNA expression was also diminished in pulmonary tissues taken from hypoxemic subjects at the time of lung transplantation. Environmental factors that induce hypoxic signaling regulate CFTR mRNA and epithelial Cl 2 transport in vitro and in vivo.

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“…We used rabbit RPTC in our studies because they grow in the absence of exogenous growth factors, and the culture conditions have been improved such that the cells exhibit normal rates of aerobic metabolism, are gluconeogenic, and have a greater degree of differentiation that most other in vitro cellular models (35). Furthermore, RPTC undergo migration and proliferation following plating and mechanical injury in an EGF receptor-dependent manner (60).…”

mentioning

confidence: 99%

Heparin-binding epidermal growth factor and Src family kinases in proliferation of renal epithelial cells

Zhuang

Kinsey²,

Rasbach³

et al. 2008

American Journal of Physiology-Renal Physiology

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Our recent studies have shown that proliferation of renal proximal tubular cells (RPTC) in the absence of growth factors requires activation of the epidermal growth factor (EGF) receptor. We sought to identify the endogenous EGF receptor ligand and investigate the mechanism(s) by which RPTC proliferate in different models. RPTC expressed both pro- and cleaved forms of heparin-binding epidermal growth factor (HB-EGF) and several metalloproteinases (MMP-2, -3, -9, and ADAM10, ADAM17) that have been reported to cleave HB-EGF. Treatment of RPTC with CRM 197, an inhibitor of HB-EGF binding to the EGF receptor, or downregulation of HB-EGF with small interfering RNA inhibited RPTC proliferation following plating. Furthermore, GM6001 (pan-MMP inhibitor), tumor-necrosis factor protease inhibitor-1 (TAPI-1; MMP and ADAM17 inhibitor), and GW280264X (ADAM10 and -17 inhibitor), but not GI254023X (ADAM10 inhibitor), attenuated the proliferation after plating. Although EGF receptor activation is required for RPTC proliferation after oxidant injury, CRM197, GM6001, and TAPI-1 did not block this response. In contrast, inhibition of Src with PP1 blocked EGF receptor activation and RPTC proliferation after oxidant injury. In addition, PP1 treatment attenuated HB-EGF-enhanced RPTC proliferation. We suggest that RPTC proliferation after plating is mediated by HB-EGF produced through an autocrine/paracrine mechanism and RPTC proliferation following oxidant injury is mediated by Src without involvement of HB-EGF.

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Improved culture conditions stimulate gluconeogenesis in primary cultures of renal proximal tubule cells

Cited by 91 publications

References 17 publications

Therapeutic Approach for Diabetic Nephropathy Using Gene Delivery of Translocase of Inner Mitochondrial Membrane 44 by Reducing Mitochondrial Superoxide Production

Therapeutic Approach for Diabetic Nephropathy Using Gene Delivery of Translocase of Inner Mitochondrial Membrane 44 by Reducing Mitochondrial Superoxide Production

Role of Oxygen Availability in CFTR Expression and Function

Heparin-binding epidermal growth factor and Src family kinases in proliferation of renal epithelial cells

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