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C Deficiency
S112 Journal of Cardiac Failure Vol. 25 No. 8S August 2019 most common variants are described in Table 1. The data demonstrates that hATTR amyloidosis manifests in a heterogenous manner irrespective of genotype, with many individuals having overlapping symptomatology. Individuals may develop a wide range of symptoms including but not limited to neuropathy, cardiac, and autonomic dysfunction. This highlights the importance of incorporating a multidisciplinary approach to the diagnosis and management of these individuals . Because of this, hATTR amyloidosis requires a high index of clinical suspicion and recognizing all these multisystem manifestations as clues to the diagnosis. Table 1. Frequency of hATTR Amyloidosis Signs and Symptoms Reported by Mutation.
out of angII and the water is returned to normal water to begin the recovery phase following heart failure. Mice were euthanized at different time points to observe gene expression from tissues collected from control mice, as well as week 3 and 5 (HF) and weeks 7 and 9 (recovery). Expression was represented as increase fold change compared to control. We assessed fibrosis and heart weight as surrogate markers of the degree of heart failure or recovery. PCR was used to quantitate OSKM gene expression. Results: There is a trend of overall elevated expression in OSKM genes in the weeks after the injury was removed, which are considered the recovery weeks. SOX2, OCT4, and KLF4 are expressed in a progressive way from low to high, peaking by the end of recovery. Fibrosis percentage showed a statistically significant decrease in recovery compared to HF (p-value <.05). Conclusions: The increased expression of OSKM in recovery period vs. HF suggest that Yamanaka factors might play an important role in recovery from HF. This could reflect contribution of these factors through stem cells or cell transitions (mesenchymal to endothelial) that finally mediate a recovery or antifibrotic process.
302 Dysregulated Cofilin 1/2 and Actin Depolymerization in Mouse Models of Cardiac Laminopathies and Heterozygous Lamin A/C Deficiency Zhili Shao, Sathyamangla V.N. Prasad, Sromona Mukherjee, W.H. Wilson Tang; Cleveland Clinic, Cleveland, OH Background: Lamin A/C (LMNA) gene mutations can cause LMNA cardiomyopathy which accounts for 6-8% dilated cardiomyopathy. Alternations in cardiomyocyte contractile structure especially in actin filaments might underlie the mechanisms of LMNA cardiomyopathy. As actin-depolymerizing factors, cofilins are essential for the dynamics of actin filaments and both cofilin 1 and 2 are reported involving in the pathogenesis of certain LMNA cardiomyopathy. Objectives: This study sought to investigate how cofilins and actin polymerization are dysregulated in mouse models of homozygous and heterozygous LMNA deficiency. We further explored related upstream signaling pathways. Methods: Heterozygous mice harboring the targeted Lmna null mutation, Lmnatm1Stw, were inbred. Homozygous Lmna-/- mice were selected by genotype. We homogenized mouse hearts from 1-month-old homozygous Lmna-/- (KO), heterozygous Lmna+/- (hets) and wild type (WT) mice, and compared their levels of cofilin 1/2, phospho-cofilin 1/2, slingshot protein phosphatase 1 (SSH1), ERK1/2, phospho-ERK1/2 and LIM Domain Kinase 1 (LIMK1) by western blot. F-actin/G-actin ratio was tested using an in vivo assay kit. Fluorescent staining for F-actin and G-actin was performed in paraffin-embedded mouse heart tissue sections. Results: Compared to WT, KO mice had minor decrease in total cofilin 1/2 and significant decrease in phospho-cofilin 1/2, suggesting more non-phosphorylated cofilins and more actin-depolymerizing activity. This explained the decreased F/Gactin ratio in KO mice. Hets demonstrated decreases in both total cofilin 1/ 2 and phospho-cofilin 1/2, suggesting they might not have more non-phosphorylated cofilins although cofilin phosphorylation had minor decrease compared to that of WT. This might be the reason why hets had similar F/G-actin ratio as WT. Fluorescent staining showed less F-actin and G-actin in KO heart tissue sections compared to those in WT and hets sections. In upstream study, we found significant decrease of SSH1 in hets and increase of SSH1 in KO mice. We also observed remarkable decrease of ERK2 in hets and increase of ERK1/2 in KO mice. In addition, we found notable decrease of LIMK1 in both hets and KO mice compared to WT. Conclusions: Significant decrease in cofilin phosphorylation and increased actin depolymerization was observed in Lmna KO mice, which might be driven by higher SSH1, ERK1/2 and lower LIMK1 levels. Lmna hets also had decreased cofilin phosphorylation which might be due to less LIMK1. But their total cofilin level deceased as well and some mechanisms might keep cofilin phosphorylated (lower SSH1 and ERK2 levels), which might have prevented actin over-depolymerization.
304 Presentation of Early Heart Failure Phenotypes in bII-Spectrin Conditional Knockout Mice Somayya J. Mohammad, Mohamed H. Derbala, Aaron Guo, Sakima A. Smith; The Ohio State University, Columbus, OH Background: bII spectrin is an actin associated protein which regulates the localization of cytoskeletal and plasma membrane protein complexes necessary for normal cellular function. In cardiac myocytes bII spectrin recruits ankyrin-B to the cardiac dyad and modulates the functions of Na+/Ca2+ exchanger, ryanodine receptor 2, ankyrin-B, actin, and aII spectrin. Disruption of the bII spectrin/ankyrin-B complex due to genetic mutation results in the onset of fatal arrhythmias. This was associated to the dysregulation of Ca2+ channels via ryanodine receptor 2 which forms the cardiac dyad. We hypothesize that loss of spectrin leads to acceleration of heart failure (HF), and plays a critical role in the SMAD pathway in the heart, and spectrin based arrhythmias are caused by abnormalities with the cardiac dyad. Methods: Transgenic bII conditional knockout (cKO) mice were regenerated with a cleaner genetic profile
303 Yamanaka Factors as Drivers of Recovery in a Mouse Model of Heart Failure Hernan G. Marcos-Abdala, Keith A. Youker, Guillermo Torre-Amione, Arvind Bhimaraj; Houston Methodist Hospital, Houston, TX Introduction: Yamanaka Factors (OCT3/4, SOX2, KLF4 and C-MYC-OSKM) are a group of genes recently identified by Yamanaka et al. as important for the creation of induced pluripotent stem cells (iPSC). OSKM genes have shown effects on Mesenchymal to Endothelial transition (MET), a process that leads to the transition of a fibroblast to an endothelial cell. We have previously shown in a non-ischemic HF model of recovery that the phenotype of HF can reverse with natural mechanisms with a normalization of ejection fraction and resolution of fibrosis. Hypothesis: Expression of OSKM genes is elevated in the early phase of recovery in a non-ischemic mouse model of HF recovery. Methods: We used our non-ischemic mouse model of recovery from HF which consists of implantation of an osmotic pump which delivers angiotensin II (angII), combined with the addition of L-NAME and NaCl in the drinking water to induce heart failure. At the end of 5 weeks (HF) the pump runs
Figure 1. LVEF differences between cKO vs Flox.
out of angII and the water is returned to normal water to begin the recovery phase following heart failure. Mice were euthanized at different time points to observe gene expression from tissues collected from control mice, as well as week 3 and 5 (HF) and weeks 7 and 9 (recovery). Expression was represented as increase fold change compared to control. We assessed fibrosis and heart weight as surrogate markers of the degree of heart failure or recovery. PCR was used to quantitate OSKM gene expression. Results: There is a trend of overall elevated expression in OSKM genes in the weeks after the injury was removed, which are considered the recovery weeks. SOX2, OCT4, and KLF4 are expressed in a progressive way from low to high, peaking by the end of recovery. Fibrosis percentage showed a statistically significant decrease in recovery compared to HF (p-value <.05). Conclusions: The increased expression of OSKM in recovery period vs. HF suggest that Yamanaka factors might play an important role in recovery from HF. This could reflect contribution of these factors through stem cells or cell transitions (mesenchymal to endothelial) that finally mediate a recovery or antifibrotic process.
302 Dysregulated Cofilin 1/2 and Actin Depolymerization in Mouse Models of Cardiac Laminopathies and Heterozygous Lamin A/C Deficiency Zhili Shao, Sathyamangla V.N. Prasad, Sromona Mukherjee, W.H. Wilson Tang; Cleveland Clinic, Cleveland, OH Background: Lamin A/C (LMNA) gene mutations can cause LMNA cardiomyopathy which accounts for 6-8% dilated cardiomyopathy. Alternations in cardiomyocyte contractile structure especially in actin filaments might underlie the mechanisms of LMNA cardiomyopathy. As actin-depolymerizing factors, cofilins are essential for the dynamics of actin filaments and both cofilin 1 and 2 are reported involving in the pathogenesis of certain LMNA cardiomyopathy. Objectives: This study sought to investigate how cofilins and actin polymerization are dysregulated in mouse models of homozygous and heterozygous LMNA deficiency. We further explored related upstream signaling pathways. Methods: Heterozygous mice harboring the targeted Lmna null mutation, Lmnatm1Stw, were inbred. Homozygous Lmna-/- mice were selected by genotype. We homogenized mouse hearts from 1-month-old homozygous Lmna-/- (KO), heterozygous Lmna+/- (hets) and wild type (WT) mice, and compared their levels of cofilin 1/2, phospho-cofilin 1/2, slingshot protein phosphatase 1 (SSH1), ERK1/2, phospho-ERK1/2 and LIM Domain Kinase 1 (LIMK1) by western blot. F-actin/G-actin ratio was tested using an in vivo assay kit. Fluorescent staining for F-actin and G-actin was performed in paraffin-embedded mouse heart tissue sections. Results: Compared to WT, KO mice had minor decrease in total cofilin 1/2 and significant decrease in phospho-cofilin 1/2, suggesting more non-phosphorylated cofilins and more actin-depolymerizing activity. This explained the decreased F/Gactin ratio in KO mice. Hets demonstrated decreases in both total cofilin 1/ 2 and phospho-cofilin 1/2, suggesting they might not have more non-phosphorylated cofilins although cofilin phosphorylation had minor decrease compared to that of WT. This might be the reason why hets had similar F/G-actin ratio as WT. Fluorescent staining showed less F-actin and G-actin in KO heart tissue sections compared to those in WT and hets sections. In upstream study, we found significant decrease of SSH1 in hets and increase of SSH1 in KO mice. We also observed remarkable decrease of ERK2 in hets and increase of ERK1/2 in KO mice. In addition, we found notable decrease of LIMK1 in both hets and KO mice compared to WT. Conclusions: Significant decrease in cofilin phosphorylation and increased actin depolymerization was observed in Lmna KO mice, which might be driven by higher SSH1, ERK1/2 and lower LIMK1 levels. Lmna hets also had decreased cofilin phosphorylation which might be due to less LIMK1. But their total cofilin level deceased as well and some mechanisms might keep cofilin phosphorylated (lower SSH1 and ERK2 levels), which might have prevented actin over-depolymerization.
304 Presentation of Early Heart Failure Phenotypes in bII-Spectrin Conditional Knockout Mice Somayya J. Mohammad, Mohamed H. Derbala, Aaron Guo, Sakima A. Smith; The Ohio State University, Columbus, OH Background: bII spectrin is an actin associated protein which regulates the localization of cytoskeletal and plasma membrane protein complexes necessary for normal cellular function. In cardiac myocytes bII spectrin recruits ankyrin-B to the cardiac dyad and modulates the functions of Na+/Ca2+ exchanger, ryanodine receptor 2, ankyrin-B, actin, and aII spectrin. Disruption of the bII spectrin/ankyrin-B complex due to genetic mutation results in the onset of fatal arrhythmias. This was associated to the dysregulation of Ca2+ channels via ryanodine receptor 2 which forms the cardiac dyad. We hypothesize that loss of spectrin leads to acceleration of heart failure (HF), and plays a critical role in the SMAD pathway in the heart, and spectrin based arrhythmias are caused by abnormalities with the cardiac dyad. Methods: Transgenic bII conditional knockout (cKO) mice were regenerated with a cleaner genetic profile
303 Yamanaka Factors as Drivers of Recovery in a Mouse Model of Heart Failure Hernan G. Marcos-Abdala, Keith A. Youker, Guillermo Torre-Amione, Arvind Bhimaraj; Houston Methodist Hospital, Houston, TX Introduction: Yamanaka Factors (OCT3/4, SOX2, KLF4 and C-MYC-OSKM) are a group of genes recently identified by Yamanaka et al. as important for the creation of induced pluripotent stem cells (iPSC). OSKM genes have shown effects on Mesenchymal to Endothelial transition (MET), a process that leads to the transition of a fibroblast to an endothelial cell. We have previously shown in a non-ischemic HF model of recovery that the phenotype of HF can reverse with natural mechanisms with a normalization of ejection fraction and resolution of fibrosis. Hypothesis: Expression of OSKM genes is elevated in the early phase of recovery in a non-ischemic mouse model of HF recovery. Methods: We used our non-ischemic mouse model of recovery from HF which consists of implantation of an osmotic pump which delivers angiotensin II (angII), combined with the addition of L-NAME and NaCl in the drinking water to induce heart failure. At the end of 5 weeks (HF) the pump runs
Figure 1. LVEF differences between cKO vs Flox.