Cardiac contractile dysfunction in Lep/Lep obesity is accompanied by NADPH oxidase activation, oxidative modification of sarco(endo)plasmic reticulum Ca2+-ATPase and myosin heavy chain isozyme switch

Li, S.-Y.; Yang, Xiaoping; Ceylan-Isik, Asli F.; Du, Min; Nair, Sreejayan; Ren, Jun

doi:10.1007/s00125-006-0229-0

Cited by 163 publications

(159 citation statements)

References 53 publications

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“…Oxidation of SERCA2a was assessed by measuring protein carbonyls in SERCA2a as described previously (25). SERCA2a protein was immunoprecipitated with anti-SERCA2a monoclonal antibody.…”

Section: Methodsmentioning

confidence: 99%

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Protective effects of Hsp70 on the structure and function of SERCA2a expressed in HEK-293 cells during heat stress

Fu¹,

Tupling²

2009

American Journal of Physiology-Heart and Circulatory Physiology

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Fu MH, Tupling AR. Protective effects of Hsp70 on the structure and function of SERCA2a expressed in HEK-293 cells during heat stress. Am J Physiol Heart Circ Physiol 296: H1175-H1183, 2009. First published February 27, 2009 doi:10.1152/ajpheart.01276.2008.-Heat shock protein 70 (Hsp70) can physically interact with and prevent thermal inactivation of sarco(endo)plasmic reticulum Ca 2ϩ -ATPase (SERCA) 1a, the SERCA isoform expressed in adult fasttwitch skeletal muscle. This study examined whether Hsp70 could physically interact with and prevent thermal inactivation of SERCA2a, the SERCA isoform expressed in heart. HEK-293 cells were cotransfected with cDNAs encoding human Hsp70 and rabbit SERCA2a (S2a/Hsp70). Cells cotransfected with SERCA2a cDNA and pMT2 (S2a/pMT2) were used as control. One-half of the cells was heat shocked at 40°C for 1 h (HS), and one-half was maintained at 37°C before harvesting the cells and isolating microsomes. Western blot analysis showed that Hsp70 and SERCA2a were colocalized in the microsomal fraction. The levels of Hsp70 were approximately fivefold higher (P Ͻ 0.05) in S2a/Hsp70 compared with S2a/pMT2 and approximately twofold higher (P Ͻ 0.05) following HS in all cells. Coimmunoprecipitation demonstrated that Hsp70 directly binds to SERCA2a. Following HS, maximal SERCA2a activity was reduced (ϳ52%, P Ͻ 0.05) in S2a/pMT2 but was increased (ϳ33%, P Ͻ 0.05) in S2a/Hsp70. Thermal inactivation of SERCA2a in S2a/pMT2 was associated with decreased (ϳ49%, P Ͻ 0.05) binding capacity for fluorescein isothiocyanate (FITC) and increased carbonyl (ϳ42%, P Ͻ 0.05) and nitrotyrosine (ϳ40%, P Ͻ 0.05) levels in SERCA2a. By contrast, the HS-induced increase in maximal SERCA2a activity observed in S2a/Hsp70 corresponded with no change (P Ͼ 0.05) in FITC-binding capacity and reductions in carbonyl (ϳ40%, P Ͻ 0.05) and nitrotyrosine (ϳ23%, P Ͻ 0.05) levels in SERCA2a compared with S2a/pMT2. These results show that Hsp70 forms a protective interaction with SERCA2a during HS actually reducing oxidation and nitrosylation of SERCA2a thus increasing its maximal activity. coimmunoprecipitatoin; carbonyl; nitrotyrosine; nucleotide binding site SARCO(ENDO)PLASMIC reticulum Ca 2ϩ -ATPases (SERCAs) are typical of the class of P-type ATPases that bind specific ions to be transported, hydrolyze ATP to form a phosphoprotein intermediate, and undergo conformational changes resulting in ion translocation (29). SERCA pumps are 110-kDa integral membrane proteins that consist of 10 transmembrane helexes (M1-M10), three cytoplasmic domains (A, actuator; N, nucleotide-binding; P, phosphorylation), and small luminal loops (48). In humans, 3 genes (ATP2A1-3) generate multiple isoforms (SERCAla,b, SERCA2a-c, SECA3a-f) by developmental or tissue-specific alternative splicing (14). Two SERCA isoforms predominate in adult striated muscle, namely SERCA1a and SERCA2a. The SERCA1a isoform consists of 994 amino acids and accounts for Ͼ99% of the SERCA isoforms expressed in adult fast-twitch skeletal muscle, whereas SERCA2a consists...

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“…Oxidation of SERCA2a was assessed by measuring protein carbonyls in SERCA2a as described previously (25). SERCA2a protein was immunoprecipitated with anti-SERCA2a monoclonal antibody.…”

Section: Methodsmentioning

confidence: 99%

“…Protein carbonyl content provides a marker of oxidative damage of SERCA2a proteins (25). Thus it was of interest to determine if Hsp70 could minimize carbonyl formation in SERCA2a molecules during heat stress.…”

Section: Expression Of Serca2a and Hsp70 In Hek-293 Cellsmentioning

confidence: 99%

Protective effects of Hsp70 on the structure and function of SERCA2a expressed in HEK-293 cells during heat stress

Fu¹,

Tupling²

2009

American Journal of Physiology-Heart and Circulatory Physiology

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“…66, 67 The effect of AngII on SERCA pump is, at least partly, mediated through NADPH oxidase and ROS. 68 In multiple experimental models of heart failure, treatment with ACEI or ARB normalizes the intracellular calcium handling, 69-71 possibly contributing to the reduction their antiarrhythmic effects in this condition.…”

Section: Raas and Ion Channelsmentioning

confidence: 99%

The renin-angiotensin-aldosterone system (RAAS) and cardiac arrhythmias

2008

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The role of the renin-angiotensin-aldosterone system (RAAS) in many cardiovascular disorders, including hypertension, cardiac hypertrophy, and atherosclerosis is well established, whereas its relationship with cardiac arrhythmias is a new area of investigation. Atrial fibrillation and malignant ventricular tachyarrhythmias, especially in the setting of cardiac hypertrophy or failure, appear to be examples of RAAS-related arrhythmias, since treatment with RAAS modulators, including angiotensin converting enzyme inhibitors, angiotensin receptor blockers and mineralocorticoid receptor blockers, reduces the incidence of these arrhythmias. RAAS has a multitude of electrophysiological effects and can potentially cause arrhythmia through a variety of mechanisms. We review new experimental results that suggest RAAS has pro-arrhythmic effects on membrane and sarcoplasmic reticulum ion channels and that increased oxidative stress is likely contributing to the increased arrhythmic incidence. A summary of ongoing clinical trials that will address the clinical usefulness of RAAS modulators for prevention or treatment of arrhythmias is presented.

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“…At the end of the treatment schedule, mice were subjected to the intraperitoneal glucose tolerance test (GTT) as described previously (16). Briefly, the mice were fasted overnight (~12 h), and glucose challenge was initiated with intraperitoneal injection of glucose (1 g/kg).…”

Section: Glucose and Insulin Tolerance Testsmentioning

confidence: 99%

Chromium Alleviates Glucose Intolerance, Insulin Resistance, and Hepatic ER Stress in Obese Mice

Nair

Dong

Kandadi

et al. 2008

Obesity

100

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objective: Chromium has gained popularity as a nutritional supplement for diabetic patients. This study evaluated the effect of chronic administration of a chromium complex of d-phenylalanine (Cr(d-phe) 3 ) on glucose and insulin tolerance in obese mice. The study tested the hypothesis that Cr(d-phe) 3 suppresses endoplasmic reticulum (ER) stress and insulin resistance in these animals. Methods and Procedures: C57BL lean and ob/ob obese mice were randomly divided to orally receive vehicle or Cr(d-phe) 3 (3.8 µg of elemental chromium/kg/day) for 6 months. Insulin sensitivity was evaluated by glucose and insulin tolerance tests. Protein levels of phosphorylated pancreatic ER kinase (PERK), α subunit of translation initiation factor 2 (eIF2α) and inositol-requiring enzyme-1 (IRE-1), p-c-Jun, and insulin receptor substrate-1 (IRS-1) phosphoserine-307 were assessed by western blotting. In vitro ER stress was induced by treating cultured muscle cells with thapsigargin in the presence or absence of Cr(d-phe) 3 . Results: ob/ob mice showed poor glucose and insulin tolerance compared to the lean controls, which was attenuated by Cr(d-phe) 3 . Markers of insulin resistance (phospho-c-Jun and IRS-1 phosphoserine) and ER stress (p-PERK, p-IRE-1, p-eIF2α), which were elevated in ob/ob mice, were attenuated following Cr(d-phe) 3 treatment. Chromium treatment was also associated with a reduction in liver triglyceride levels and lipid accumulation. In cultured myotubes, Cr(d-phe) 3 attenuated ER stress induced by thapsigargin. Discussion: Oral Cr(d-phe) 3 treatment reduces glucose intolerance, insulin resistance, and hepatic ER stress in obese, insulin-resistant mice.

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Cardiac contractile dysfunction in Lep/Lep obesity is accompanied by NADPH oxidase activation, oxidative modification of sarco(endo)plasmic reticulum Ca2+-ATPase and myosin heavy chain isozyme switch

Cited by 163 publications

References 53 publications

Protective effects of Hsp70 on the structure and function of SERCA2a expressed in HEK-293 cells during heat stress

Protective effects of Hsp70 on the structure and function of SERCA2a expressed in HEK-293 cells during heat stress

The renin-angiotensin-aldosterone system (RAAS) and cardiac arrhythmias

Chromium Alleviates Glucose Intolerance, Insulin Resistance, and Hepatic ER Stress in Obese Mice

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