Abstract 253: Pharmacological and Genetic Inhibition of Transient Receptor Potential Canonical 6 (TRPC6) as a Novel Treatment for Heart Failure and Duchenne Muscular Dystrophy (DMD) Pharmacological and Genetic Inhibition of Transient Receptor Potential Canonical 6 (TRPC6) as a Novel Treatment for Heart Failure and Duchenne Muscular Dystrophy (DMD)

Heart failure is a major cause of morbidity and mortality. The transient receptor potential canonical (TRPC) family of channels mediate pathologic cardiac remodeling. In particular, TRPC6 participates in a self-propagating circuit that amplifies cardiac hypertrophy and fibrosis. The objective of this study was to explore biventricular expression of TRPCs in advanced heart failure. Methods: Viable left (LV) and right (RV) ventricular free wall tissue was obtained from human subjects with end-stage heart failure (n=12) referred for transplantation or biventricular assist devices. Control LV and RV tissue was obtained from the National Disease Research Interchange (n=3/group). To explore TRPC expression in a murine model, adult male C57BL/6 mice underwent thoracic aortic constriction (TAC) for 10 weeks (n=6/group). Biventricular tissue was analyzed by real-time polymerase chain reaction. Results: Compared to normal LV and RV, levels of TRPC 1, 3, 4 and 6 were increased in failing LV and RV samples, respectively. Levels of TRPC1 and TRPC6 were greater in failing RV than failing LV samples. TRPC 5 and 7 expression were not consistently detected in normal or failing tissue samples. Compared to sham LV, levels of TPRC 1, 4 and 6 increased in the LV after TAC. Compared to sham RV, levels of TRPC 3, 4, and 6 increased in the RV after TAC. Levels of TRPC3 were greater in the RV than LV after TAC. Conclusions: Our results identify distinct profiles of TRPC expression in the RV versus LV in both human tissue and in a murine model of advanced biventricular failure. Levels of select TRPCs are higher in the failing RV compared to LV, suggesting a potentially important role for TRPCs in RV remodeling.

Download Full-text

Transient receptor potential channel 6 regulates abnormal cardiac S-nitrosylation in Duchenne muscular dystrophy

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1712623114 ◽

2017 ◽

Vol 114 (50) ◽

pp. E10763-E10771 ◽

Cited By ~ 8

Author(s):

Heaseung Sophia Chung ◽

Grace E. Kim ◽

Ronald J. Holewinski ◽

Vidya Venkatraman ◽

Guangshuo Zhu ◽

...

Keyword(s):

Nitric Oxide ◽

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Transient Receptor Potential ◽

Receptor Potential ◽

Left Ventricular ◽

Muscle Disease ◽

Intracellular Ca ◽

Transient Receptor ◽

The Impact

Duchenne muscular dystrophy (DMD) is an X-linked disorder with dystrophin loss that results in skeletal and cardiac muscle weakening and early death. Loss of the dystrophin–sarcoglycan complex delocalizes nitric oxide synthase (NOS) to alter its signaling, and augments mechanosensitive intracellular Ca2+ influx. The latter has been coupled to hyperactivation of the nonselective cation channel, transient receptor potential canonical channel 6 (Trpc6), in isolated myocytes. As Ca2+ also activates NOS, we hypothesized that Trpc6 would help to mediate nitric oxide (NO) dysregulation and that this would be manifest in increased myocardial S-nitrosylation, a posttranslational modification increasingly implicated in neurodegenerative, inflammatory, and muscle disease. Using a recently developed dual-labeling proteomic strategy, we identified 1,276 S-nitrosylated cysteine residues [S-nitrosothiol (SNO)] on 491 proteins in resting hearts from a mouse model of DMD (dmdmdx:utrn+/−). These largely consisted of mitochondrial proteins, metabolic regulators, and sarcomeric proteins, with 80% of them also modified in wild type (WT). S-nitrosylation levels, however, were increased in DMD. Genetic deletion of Trpc6 in this model (dmdmdx:utrn+/−:trpc6−/−) reversed ∼70% of these changes. Trpc6 deletion also ameliorated left ventricular dilation, improved cardiac function, and tended to reduce fibrosis. Furthermore, under catecholamine stimulation, which also increases NO synthesis and intracellular Ca2+ along with cardiac workload, the hypernitrosylated state remained as it did at baseline. However, the impact of Trpc6 deletion on the SNO proteome became less marked. These findings reveal a role for Trpc6-mediated hypernitrosylation in dmdmdx:utrn+/− mice and support accumulating evidence that implicates nitrosative stress in cardiac and muscle disease.

Download Full-text

Abstract 250: Canonical Transient Receptor Potential Channel 6 Ameliorates Increased Cardiac S-nitrosylation in Duchenne Muscular Dystrophy

Circulation Research ◽

10.1161/res.121.suppl_1.250 ◽

2017 ◽

Vol 121 (suppl_1) ◽

Author(s):

Grace E Kim ◽

Heaseung S Chung ◽

Ronald J Holewinski ◽

Guangshuo Zhu ◽

Vidya Venkatraman ◽

...

Keyword(s):

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Transient Receptor Potential ◽

Nitrosative Stress ◽

Mechanical Load ◽

Gene Activation ◽

Receptor Potential ◽

Left Ventricular ◽

Tissue Growth ◽

Transient Receptor

Duchenne muscular dystrophy (DMD) is an X-linked disorder that markedly weakens skeletal and cardiac muscle to cause early death. Its elimination of dystrophin disrupts nitric oxide (NO) signaling and amplifies intracellular Ca 2+ responses to mechanical load. We have shown the latter is linked to hyperstimulated transient receptor potential canonical 6 (TRPC6) cation channels. As Ca 2+ also activates NO synthase, we hypothesized TRPC6 couples to redox-dependent nitrosative stress to broadly impact protein S-nitrosylation (SNO). Using an unbiased, dual-labeling proteomic strategy we identified 1276 SNO sites on 491 proteins in DMD hearts (dystrophin/utrophin +/- ), of which 102 sites among 69 proteins were unique to DMD. Many of the targeted proteins were mitochondrial or metabolic regulators and sarcomere proteins - including titin, myosin binding protein-C, α-myosin heavy-chain, and tropomyosin α1 - that were hyper-nitrosylated. A key redox regulator peroxiredoxin1 was also hyper-nitrosylated at Cys173, a site previously shown to be a requisite regulator of its dimerization and enzymatic activity. DMD mice were then crossed into a Trpc6 -/- background, and proteomic analysis now found 70% of SNO targeted residues in DMD were reversed towards normal (p<0.01, χ 2 ). Trpc6 deletion improved left ventricular dilation (13.7±1.2mm, 22.4±3.9mm, 15.3±2.3mm; p<0.01), fractional shortening (58.5±0.5%, 50.3±1.0%, 59.6±1.2%, p<0.001), and fibrosis (2.3±0.9%, 6.2±0.9%, 3.7±0.6%; p<0.0001) in WT, DMD and DMD-TRPC6 -/- respectively (1-way ANOVA), and reversed pro-fibrotic gene activation (connective tissue growth factor, fibronectin1 and osteopontin). These results provide the first broad-based SNO analysis of the DMD heart, and support linkage between abnormal calcium via TRPC6, nitrosative stress and cardiac disease.

Download Full-text

Small-molecule activation of lysosomal TRP channels ameliorates Duchenne muscular dystrophy in mouse models

Science Advances ◽

10.1126/sciadv.aaz2736 ◽

2020 ◽

Vol 6 (6) ◽

pp. eaaz2736 ◽

Cited By ~ 3

Author(s):

Lu Yu ◽

Xiaoli Zhang ◽

Yexin Yang ◽

Dan Li ◽

Kaiyuan Tang ◽

...

Keyword(s):

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Transient Receptor Potential ◽

Trp Channels ◽

Elevated Serum ◽

Receptor Potential ◽

Small Molecule Activation ◽

Activation Of Transcription ◽

Transient Receptor

Duchenne muscular dystrophy (DMD) is a devastating disease caused by mutations in dystrophin that compromise sarcolemma integrity. Currently, there is no treatment for DMD. Mutations in transient receptor potential mucolipin 1 (ML1), a lysosomal Ca2+ channel required for lysosomal exocytosis, produce a DMD-like phenotype. Here, we show that transgenic overexpression or pharmacological activation of ML1 in vivo facilitates sarcolemma repair and alleviates the dystrophic phenotypes in both skeletal and cardiac muscles of mdx mice (a mouse model of DMD). Hallmark dystrophic features of DMD, including myofiber necrosis, central nucleation, fibrosis, elevated serum creatine kinase levels, reduced muscle force, impaired motor ability, and dilated cardiomyopathies, were all ameliorated by increasing ML1 activity. ML1-dependent activation of transcription factor EB (TFEB) corrects lysosomal insufficiency to diminish muscle damage. Hence, targeting lysosomal Ca2+ channels may represent a promising approach to treat DMD and related muscle diseases.

Download Full-text