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Intravenous AAV8 Encoding Urocortin-2 Increases Function of the Failing Heart in Mice.

Lai NC, Gao MH, Giamouridis D, Suarez J, Miyanohara A, Parikh J, Hightower S, Guo T, Dillmann W, Kim YC, Diaz-Juarez J, Hammond HK - Hum. Gene Ther. (2015)

Bottom Line: UCn2 gene transfer was associated with increased peak systolic Ca(2+) transient amplitude and rate of Ca(2+) decline and increased SERCA2a expression.We conclude that a single IV injection of AAV8.UCn2 increases function of the failing heart.The simplicity of IV injection of a vector encoding a gene with beneficial paracrine effects to increase cardiac function is an attractive potential clinical strategy.

View Article: PubMed Central - PubMed

Affiliation: 1 VA San Diego Healthcare System , San Diego, CA 92161.

ABSTRACT
Urocortin-2 (UCn2) peptide infusion increases cardiac function in patients with heart failure, but chronic peptide infusion is cumbersome, is costly, and provides only short-term benefits. Gene transfer would circumvent these shortcomings. We previously showed that a single intravenous (IV) injection of AAV8.UCn2 increases plasma UCn2 and left ventricular (LV) systolic and diastolic function for at least 7 months in normal mice. Here we test the hypothesis that IV delivery of AAV8.UCn2 increases function of the failing heart. Myocardial infarction (MI, by coronary ligation) was used to induce heart failure, which was assessed by echocardiography 3 weeks after MI. Mice with LV ejection fraction (EF) <25% received IV delivery of AAV8.UCn2 (5×10(11) gc) or saline, and 5 weeks later echocardiography showed increased LV EF in mice that received UCn2 gene transfer (p=0.01). In vivo physiological studies showed a 2-fold increase in peak rate of LV pressure development (LV +dP/dt; p<0.0001) and a 1.6-fold increase in peak rate of LV pressure decay (LV -dP/dt; p=0.0007), indicating increased LV systolic and diastolic function in treated mice. UCn2 gene transfer was associated with increased peak systolic Ca(2+) transient amplitude and rate of Ca(2+) decline and increased SERCA2a expression. In addition, UCn2 gene transfer reduced Thr286 phosphorylation of Cam kinase II, and increased expression of cardiac myosin light chain kinase, findings that would be anticipated to increase function of the failing heart. We conclude that a single IV injection of AAV8.UCn2 increases function of the failing heart. The simplicity of IV injection of a vector encoding a gene with beneficial paracrine effects to increase cardiac function is an attractive potential clinical strategy.

No MeSH data available.


Related in: MedlinePlus

Cardiac myocyte cAMP-PKA signaling. LV samples (A, C, D) or cardiac myocytes (B) were obtained from mice with heart failure (HF) and from mice with HF that had received AAV8.UCn2 (UCn2). Cyclic AMP and PKA activity were assessed in the unstimulated (basal) state and after stimulation with isoproterenol (Iso, 10 μM, 10 min) and, in separate experiments, NKH477 (NKH, 10 μM, 10 min), a water-soluble forskolin analog that stimulates adenylate cyclase independent of β-adrenergic receptors. Numbers in bars denote group size. (A) cAMP production: no group differences were seen in basal, Iso, or NKH477-stimulated cAMP production. (B) PKA activity: no group differences were seen in basal, Iso, or NKH477-stimulated conditions. (C) CamK II expression and phosphorylation: UCn2 gene transfer was associated with reduced Thr286 phosphorylation of CamK II (left panel, normalized to GAPDH). Total CamK II was unchanged. (D) Cardiac myosin light chain kinase: UCn2 gene transfer was associated with increased cardiac myosin light chain kinase (cMLCK) protein (left panel, normalized to GAPDH). In all graphs, bars denote mean+SE; numbers in bars denote group size, numbers above bars from Student's t-test (unpaired, 2-tailed vs. control groups).
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f4: Cardiac myocyte cAMP-PKA signaling. LV samples (A, C, D) or cardiac myocytes (B) were obtained from mice with heart failure (HF) and from mice with HF that had received AAV8.UCn2 (UCn2). Cyclic AMP and PKA activity were assessed in the unstimulated (basal) state and after stimulation with isoproterenol (Iso, 10 μM, 10 min) and, in separate experiments, NKH477 (NKH, 10 μM, 10 min), a water-soluble forskolin analog that stimulates adenylate cyclase independent of β-adrenergic receptors. Numbers in bars denote group size. (A) cAMP production: no group differences were seen in basal, Iso, or NKH477-stimulated cAMP production. (B) PKA activity: no group differences were seen in basal, Iso, or NKH477-stimulated conditions. (C) CamK II expression and phosphorylation: UCn2 gene transfer was associated with reduced Thr286 phosphorylation of CamK II (left panel, normalized to GAPDH). Total CamK II was unchanged. (D) Cardiac myosin light chain kinase: UCn2 gene transfer was associated with increased cardiac myosin light chain kinase (cMLCK) protein (left panel, normalized to GAPDH). In all graphs, bars denote mean+SE; numbers in bars denote group size, numbers above bars from Student's t-test (unpaired, 2-tailed vs. control groups).

Mentions: LV samples and cardiac myocytes isolated from hearts of both groups showed no differences in cAMP or PKA activity (Fig. 4). Cyclic AMP production and PKA activity were assessed before and after stimulation with isoproterenol or NKH477, a water-soluble forskolin analog that stimulates adenylate cyclase independently of β-adrenergic receptors. No group differences were seen in basal, Iso, or NKH477-stimulated cAMP production (Fig. 4A) or in PKA activity (Fig. 4B). Expression of PKA family proteins (catalytic α unit and regulatory α and β subunits and their phosphorylation) was not altered (data not shown).


Intravenous AAV8 Encoding Urocortin-2 Increases Function of the Failing Heart in Mice.

Lai NC, Gao MH, Giamouridis D, Suarez J, Miyanohara A, Parikh J, Hightower S, Guo T, Dillmann W, Kim YC, Diaz-Juarez J, Hammond HK - Hum. Gene Ther. (2015)

Cardiac myocyte cAMP-PKA signaling. LV samples (A, C, D) or cardiac myocytes (B) were obtained from mice with heart failure (HF) and from mice with HF that had received AAV8.UCn2 (UCn2). Cyclic AMP and PKA activity were assessed in the unstimulated (basal) state and after stimulation with isoproterenol (Iso, 10 μM, 10 min) and, in separate experiments, NKH477 (NKH, 10 μM, 10 min), a water-soluble forskolin analog that stimulates adenylate cyclase independent of β-adrenergic receptors. Numbers in bars denote group size. (A) cAMP production: no group differences were seen in basal, Iso, or NKH477-stimulated cAMP production. (B) PKA activity: no group differences were seen in basal, Iso, or NKH477-stimulated conditions. (C) CamK II expression and phosphorylation: UCn2 gene transfer was associated with reduced Thr286 phosphorylation of CamK II (left panel, normalized to GAPDH). Total CamK II was unchanged. (D) Cardiac myosin light chain kinase: UCn2 gene transfer was associated with increased cardiac myosin light chain kinase (cMLCK) protein (left panel, normalized to GAPDH). In all graphs, bars denote mean+SE; numbers in bars denote group size, numbers above bars from Student's t-test (unpaired, 2-tailed vs. control groups).
© Copyright Policy - open-access
Related In: Results  -  Collection

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f4: Cardiac myocyte cAMP-PKA signaling. LV samples (A, C, D) or cardiac myocytes (B) were obtained from mice with heart failure (HF) and from mice with HF that had received AAV8.UCn2 (UCn2). Cyclic AMP and PKA activity were assessed in the unstimulated (basal) state and after stimulation with isoproterenol (Iso, 10 μM, 10 min) and, in separate experiments, NKH477 (NKH, 10 μM, 10 min), a water-soluble forskolin analog that stimulates adenylate cyclase independent of β-adrenergic receptors. Numbers in bars denote group size. (A) cAMP production: no group differences were seen in basal, Iso, or NKH477-stimulated cAMP production. (B) PKA activity: no group differences were seen in basal, Iso, or NKH477-stimulated conditions. (C) CamK II expression and phosphorylation: UCn2 gene transfer was associated with reduced Thr286 phosphorylation of CamK II (left panel, normalized to GAPDH). Total CamK II was unchanged. (D) Cardiac myosin light chain kinase: UCn2 gene transfer was associated with increased cardiac myosin light chain kinase (cMLCK) protein (left panel, normalized to GAPDH). In all graphs, bars denote mean+SE; numbers in bars denote group size, numbers above bars from Student's t-test (unpaired, 2-tailed vs. control groups).
Mentions: LV samples and cardiac myocytes isolated from hearts of both groups showed no differences in cAMP or PKA activity (Fig. 4). Cyclic AMP production and PKA activity were assessed before and after stimulation with isoproterenol or NKH477, a water-soluble forskolin analog that stimulates adenylate cyclase independently of β-adrenergic receptors. No group differences were seen in basal, Iso, or NKH477-stimulated cAMP production (Fig. 4A) or in PKA activity (Fig. 4B). Expression of PKA family proteins (catalytic α unit and regulatory α and β subunits and their phosphorylation) was not altered (data not shown).

Bottom Line: UCn2 gene transfer was associated with increased peak systolic Ca(2+) transient amplitude and rate of Ca(2+) decline and increased SERCA2a expression.We conclude that a single IV injection of AAV8.UCn2 increases function of the failing heart.The simplicity of IV injection of a vector encoding a gene with beneficial paracrine effects to increase cardiac function is an attractive potential clinical strategy.

View Article: PubMed Central - PubMed

Affiliation: 1 VA San Diego Healthcare System , San Diego, CA 92161.

ABSTRACT
Urocortin-2 (UCn2) peptide infusion increases cardiac function in patients with heart failure, but chronic peptide infusion is cumbersome, is costly, and provides only short-term benefits. Gene transfer would circumvent these shortcomings. We previously showed that a single intravenous (IV) injection of AAV8.UCn2 increases plasma UCn2 and left ventricular (LV) systolic and diastolic function for at least 7 months in normal mice. Here we test the hypothesis that IV delivery of AAV8.UCn2 increases function of the failing heart. Myocardial infarction (MI, by coronary ligation) was used to induce heart failure, which was assessed by echocardiography 3 weeks after MI. Mice with LV ejection fraction (EF) <25% received IV delivery of AAV8.UCn2 (5×10(11) gc) or saline, and 5 weeks later echocardiography showed increased LV EF in mice that received UCn2 gene transfer (p=0.01). In vivo physiological studies showed a 2-fold increase in peak rate of LV pressure development (LV +dP/dt; p<0.0001) and a 1.6-fold increase in peak rate of LV pressure decay (LV -dP/dt; p=0.0007), indicating increased LV systolic and diastolic function in treated mice. UCn2 gene transfer was associated with increased peak systolic Ca(2+) transient amplitude and rate of Ca(2+) decline and increased SERCA2a expression. In addition, UCn2 gene transfer reduced Thr286 phosphorylation of Cam kinase II, and increased expression of cardiac myosin light chain kinase, findings that would be anticipated to increase function of the failing heart. We conclude that a single IV injection of AAV8.UCn2 increases function of the failing heart. The simplicity of IV injection of a vector encoding a gene with beneficial paracrine effects to increase cardiac function is an attractive potential clinical strategy.

No MeSH data available.


Related in: MedlinePlus