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Exercise Mitigates Calpain 1 Induced Cardiac Dysfunction Through PCP4 in Diabetes
Author(s) -
Chaturvedi Pankaj,
Kunkel George H,
Familtseva Anastasia,
Kalani Anuradha,
Tyagi Suresh C
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.954.1
Subject(s) - calpain , calpastatin , calmodulin , medicine , calcium , endocrinology , protein kinase a , microbiology and biotechnology , diabetic cardiomyopathy , downregulation and upregulation , kinase , biology , chemistry , biochemistry , heart failure , cardiomyopathy , enzyme , gene
Calpain 1 is a ubiquitous calcium dependent cysteine protease and found in cytoplasm as well as mitochondria. We have reported earlier that active calpain 1 is translocated from cytosol to mitochondria and activates MMP9. Although studies have reported that activation of calpain 1 is deleterious to the heart in various aspects but there are no reports whether calpain 1 can degrade purkinje cell protein (PCP4) and affect cardiac rhythm in diabetes. Therefore, we hypothesize that calpain 1 degrades PCP4 in diabetes to cause cardiac dysfunction and exercise can mitigate this. To test this hypothesis we recruited four groups of mice 1)db/+ control, 2)db/+ control with exercise, 3)db/db, 4)db/db with exercise. The mice were exercised on treadmill at 7m/min for 300m for 8 weeks and in agreement with the American Veterinary Research Guidelines. HL‐1 atrial cell line for in vitro studies and isolated cardiomyocytes for ex‐vivo studies were used. To evaluate whether activation of calpain can degrade PCP4 we treated the isolated cardiomyocytes with high calcium (40mM) till they lose their shape and evaluated the expression of PCP4, calmodulin, calmodulin kinase and calpastatin with Western blots and real time PCR. The induction of high levels of calpain 1 significantly downregulated PCP4 along with upregulated levels of calmodulin and calmodulin kinase. We used the CRISPR/Cas9 plasmid to knock down calpain in HL‐1 myocytes which restored the levels of PCP4 along with calmodulin and calmodulin kinase. In vivo, we found upregulated levels of calpain 1 in db/db mice as compared to controls which were mitigated in the exercised mice. Exercise also mitigated the levels of PCP4, calmodulin and calmodulin kinase in db/db mice. Conclusively our data strongly suggests that in diabetes there is high induction of calpain 1 with degrades PCP4, a protein important for cardiac rhythm and exercise can mitigate arrhythmias. Support or Funding Information Acknowledgements: This work was supported by NIH grants HL‐74185 and HL‐108621 and AHA grant 15POST23110021