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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

Cytosolic Ca2+ transients in cardiac myocytes from mice with heart failure (HF) 5 weeks after IV AAV8.UCn2 (HF+UCn2) or IV saline. (A and B) Basal Ca2+ released (systolic–diastolic Ca2+) was increased in cardiac myocytes from HF+UCn2 mice (p=0.0001). (A) Representative Indo-1 Ca2+ transient recordings from one heart in each group showed increased peak Ca2+ in cardiac myocytes isolated from mice with heart failure 5 weeks after UCn2 gene transfer. (B) Summary data from three mice per group are shown. (C and D) Time to Ca2+ decline (t½, Tau) was shortened in cardiac myocytes from mice with heart failure 5 weeks after UCn2 gene transfer. (C) Representative normalized Ca2+ transients from cardiac myocytes from one heart in each group. (D) Summary data from three mice per group are shown. For (A) and (C), each curve is the average of 30 cardiac myocytes from one heart from each group. For (B) and (D), summary data from 3 animals per group include analysis of 146 individual cardiac myocytes (86, saline; 60, AAV8.UCn2). For (B) and (D), bars denote mean+SE; numbers in bars denote number of cardiac myocytes; numbers above bars indicate p-values from Student's t-test (unpaired, 2-tailed). (E) Summary (top panel) of immunoblotting data (bottom panel) indicates that UCn2 gene transfer increased SERCA2a protein in LV from normal mice and from mice with heart failure. Expression and phosphorylation of phospholamban (PLB) and troponin I (TnI) were not affected. Bars denote mean+SE; numbers in bars denote group size; numbers above bars from Student's t-test (unpaired, 2-tailed vs. control).
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f3: Cytosolic Ca2+ transients in cardiac myocytes from mice with heart failure (HF) 5 weeks after IV AAV8.UCn2 (HF+UCn2) or IV saline. (A and B) Basal Ca2+ released (systolic–diastolic Ca2+) was increased in cardiac myocytes from HF+UCn2 mice (p=0.0001). (A) Representative Indo-1 Ca2+ transient recordings from one heart in each group showed increased peak Ca2+ in cardiac myocytes isolated from mice with heart failure 5 weeks after UCn2 gene transfer. (B) Summary data from three mice per group are shown. (C and D) Time to Ca2+ decline (t½, Tau) was shortened in cardiac myocytes from mice with heart failure 5 weeks after UCn2 gene transfer. (C) Representative normalized Ca2+ transients from cardiac myocytes from one heart in each group. (D) Summary data from three mice per group are shown. For (A) and (C), each curve is the average of 30 cardiac myocytes from one heart from each group. For (B) and (D), summary data from 3 animals per group include analysis of 146 individual cardiac myocytes (86, saline; 60, AAV8.UCn2). For (B) and (D), bars denote mean+SE; numbers in bars denote number of cardiac myocytes; numbers above bars indicate p-values from Student's t-test (unpaired, 2-tailed). (E) Summary (top panel) of immunoblotting data (bottom panel) indicates that UCn2 gene transfer increased SERCA2a protein in LV from normal mice and from mice with heart failure. Expression and phosphorylation of phospholamban (PLB) and troponin I (TnI) were not affected. Bars denote mean+SE; numbers in bars denote group size; numbers above bars from Student's t-test (unpaired, 2-tailed vs. control).

Mentions: Basal Ca2+ released (systolic–diastolic Ca2+) was increased in cardiac myocytes from heart failure mice that had received UCn2 gene transfer (p=0.0001; Fig. 3A and B). UCn2 gene transfer was also associated with a reduced Ca2+ decline time (t½, Tau) in cardiac myocytes from mice with heart failure 5 weeks after UCn2 gene transfer p=0.001; Fig. 3C and D). Increased UCn2 was associated with increased expression of SERCA2a mRNA and protein in normal and failing LV (Fig. 3E). However, no group differences were seen in LV protein expression and phosphorylation of PLB or TnI (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)

Cytosolic Ca2+ transients in cardiac myocytes from mice with heart failure (HF) 5 weeks after IV AAV8.UCn2 (HF+UCn2) or IV saline. (A and B) Basal Ca2+ released (systolic–diastolic Ca2+) was increased in cardiac myocytes from HF+UCn2 mice (p=0.0001). (A) Representative Indo-1 Ca2+ transient recordings from one heart in each group showed increased peak Ca2+ in cardiac myocytes isolated from mice with heart failure 5 weeks after UCn2 gene transfer. (B) Summary data from three mice per group are shown. (C and D) Time to Ca2+ decline (t½, Tau) was shortened in cardiac myocytes from mice with heart failure 5 weeks after UCn2 gene transfer. (C) Representative normalized Ca2+ transients from cardiac myocytes from one heart in each group. (D) Summary data from three mice per group are shown. For (A) and (C), each curve is the average of 30 cardiac myocytes from one heart from each group. For (B) and (D), summary data from 3 animals per group include analysis of 146 individual cardiac myocytes (86, saline; 60, AAV8.UCn2). For (B) and (D), bars denote mean+SE; numbers in bars denote number of cardiac myocytes; numbers above bars indicate p-values from Student's t-test (unpaired, 2-tailed). (E) Summary (top panel) of immunoblotting data (bottom panel) indicates that UCn2 gene transfer increased SERCA2a protein in LV from normal mice and from mice with heart failure. Expression and phosphorylation of phospholamban (PLB) and troponin I (TnI) were not affected. Bars denote mean+SE; numbers in bars denote group size; numbers above bars from Student's t-test (unpaired, 2-tailed vs. control).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4492611&req=5

f3: Cytosolic Ca2+ transients in cardiac myocytes from mice with heart failure (HF) 5 weeks after IV AAV8.UCn2 (HF+UCn2) or IV saline. (A and B) Basal Ca2+ released (systolic–diastolic Ca2+) was increased in cardiac myocytes from HF+UCn2 mice (p=0.0001). (A) Representative Indo-1 Ca2+ transient recordings from one heart in each group showed increased peak Ca2+ in cardiac myocytes isolated from mice with heart failure 5 weeks after UCn2 gene transfer. (B) Summary data from three mice per group are shown. (C and D) Time to Ca2+ decline (t½, Tau) was shortened in cardiac myocytes from mice with heart failure 5 weeks after UCn2 gene transfer. (C) Representative normalized Ca2+ transients from cardiac myocytes from one heart in each group. (D) Summary data from three mice per group are shown. For (A) and (C), each curve is the average of 30 cardiac myocytes from one heart from each group. For (B) and (D), summary data from 3 animals per group include analysis of 146 individual cardiac myocytes (86, saline; 60, AAV8.UCn2). For (B) and (D), bars denote mean+SE; numbers in bars denote number of cardiac myocytes; numbers above bars indicate p-values from Student's t-test (unpaired, 2-tailed). (E) Summary (top panel) of immunoblotting data (bottom panel) indicates that UCn2 gene transfer increased SERCA2a protein in LV from normal mice and from mice with heart failure. Expression and phosphorylation of phospholamban (PLB) and troponin I (TnI) were not affected. Bars denote mean+SE; numbers in bars denote group size; numbers above bars from Student's t-test (unpaired, 2-tailed vs. control).
Mentions: Basal Ca2+ released (systolic–diastolic Ca2+) was increased in cardiac myocytes from heart failure mice that had received UCn2 gene transfer (p=0.0001; Fig. 3A and B). UCn2 gene transfer was also associated with a reduced Ca2+ decline time (t½, Tau) in cardiac myocytes from mice with heart failure 5 weeks after UCn2 gene transfer p=0.001; Fig. 3C and D). Increased UCn2 was associated with increased expression of SERCA2a mRNA and protein in normal and failing LV (Fig. 3E). However, no group differences were seen in LV protein expression and phosphorylation of PLB or TnI (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