title: cAMP signaling prevents podocyte apoptosis via activation of protein kinase A and mitochondrial fusion.
abstract: Our previous in vitro studies suggested that cyclic AMP (cAMP) signaling prevents adriamycin (ADR) and puromycin aminonucleoside (PAN)-induced apoptosis in podocytes. As cAMP is an important second messenger and plays a key role in cell proliferation, differentiation and cytoskeleton formation via protein kinase A (PKA) or exchange protein directly activated by cAMP (Epac) pathways, we sought to determine the role of PKA or Epac signaling in cAMP-mediated protection of podocytes. In the ADR nephrosis model, we found that forskolin, a selective activator of adenylate cyclase, attenuated albuminuria and improved the expression of podocyte marker WT-1. When podocytes were treated with pCPT-cAMP (a selective cAMP/PKA activator), PKA activation was increased in a time-dependent manner and prevented PAN-induced podocyte loss and caspase 3 activation, as well as a reduction in mitochondrial membrane potential. We found that PAN and ADR resulted in a decrease in Mfn1 expression and mitochondrial fission in podocytes. pCPT-cAMP restored Mfn1 expression in puromycin or ADR-treated podocytes and induced Drp1 phosphorylation, as well as mitochondrial fusion. Treating podocytes with arachidonic acid resulted in mitochondrial fission, podocyte loss and cleaved caspase 3 production. Arachidonic acid abolished the protective effects of pCPT-cAMP on PAN-treated podocytes. Mdivi, a mitochondrial division inhibitor, prevented PAN-induced cleaved caspase 3 production in podocytes. We conclude that activation of cAMP alleviated murine podocyte caused by ADR. PKA signaling resulted in mitochondrial fusion in podocytes, which at least partially mediated the effects of cAMP.
authors.affiliation: Renal Division and Molecular Cell Lab for Kidney Disease, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Li
authors.affiliation: Renal Division and Molecular Cell Lab for Kidney Disease, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Tao
authors.affiliation: Renal Division and Molecular Cell Lab for Kidney Disease, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Kewei
authors.initials: K
authors.lastname: Xie
authors.affiliation: Renal Division and Molecular Cell Lab for Kidney Disease, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Ni
authors.affiliation: Renal Division and Molecular Cell Lab for Kidney Disease, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Renal Division and Molecular Cell Lab for Kidney Disease, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Wei
authors.affiliation: Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America.
authors.forename: Peter Y
authors.initials: PY
authors.lastname: Chuang
authors.affiliation: Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America; Renal Section, James J Peter Veterans Affairs Medical Center, Bronx, New York, United States of America.
authors.forename: John Cijiang
authors.initials: JC
authors.lastname: He
authors.affiliation: Renal Division and Molecular Cell Lab for Kidney Disease, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Leyi
authors.initials: L
authors.lastname: Gu
mesh_terms: D000818:Animals; D017209:Apoptosis; D016718:Arachidonic Acid / Q000494:pharmacology; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D002461:Cell Line, Transformed; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism* / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics* / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D034281:Dynamins / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000494:pharmacology; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D007668:Kidney / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D063154:Mitochondrial Dynamics / Q000187:drug effects; D009401:Nephrosis / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D050199:Podocytes / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D011692:Puromycin Aminonucleoside / Q000494:pharmacology; D052999:Quinazolinones / Q000494:pharmacology; D015398:Signal Transduction; D025721:WT1 Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C549041:3-(2,4-dichloro-5-methoxyphenyl)-2-sulfanyl-4(3H)-quinazolinone; D020536:Enzyme Activators; D052999:Quinazolinones; D025721:WT1 Proteins; D005576:Colforsin; D016718:Arachidonic Acid; D011692:Puromycin Aminonucleoside; D004317:Doxorubicin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D053148:Caspase 3; D020558:GTP Phosphohydrolases; C488750:Mfn1 protein, mouse; C486391:Dnm1l protein, mouse; D034281:Dynamins