Author ORCID Identifier
Date of Award
Doctor of Philosophy (PhD)
Aims: Valosin-containing protein (VCP) has recently been identified as a novel mediator of mitochondrial respiration and cell survival in the heart, in which increased inducible nitric oxide synthase (iNOS) expression and activity is considered an essential mechanistic link in the cardioprotection conferred by VCP. iNOS is one of the three isoforms of nitric oxide synthase (NOS) that generates nitric oxide (NO) from L-arginine, which can then react with cysteine residues in proteins to form protein S-nitrosothiols (SNOs). The study aimed to investigate whether VCP directly mediates protein S-nitrosylation in the heart through the iNOS/NO/SNO pathway. We hypothesized that VCP plays a crucial role in mediating mitochondrial protein S-nitrosylation through an iNOS-dependent mechanism in the heart. To test this hypothesis, we utilized four distinct transgenic (TG) mouse models: cardiac-specific VCP TG mice, bigenic iNOS knockout (KO) with VCP overexpression mice (VCP TG/iNOS KO−/−), cardiac-specific dominant-negative (DN) VCP TG mice, and cardiac-specific VCP KO mice.
Methods and results: To investigate the potential impact of VCP on both overall and specific protein S-nitrosylation in mouse heart tissues, we utilized a biotin switch assay combined with streptavidin purification. Our results showed that VCP overexpression increased S-nitrosylation of both VCP and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in the heart, which was diminished by genetic iNOS deletion. Conversely, function inhibition of VCP resulted in a decrease in the S-nitrosylation levels of VCP and the mitochondrial respiration complex I, but did not affect the S-nitrosylation level of GAPDH in the heart.
Conclusion: Taken collectively, these data provide compelling evidence that VCP could serve as a novel mediator of cardiac protein S-nitrosylation through an iNOS-dependent mechanism.
Shi, Xiaomeng, "The Role of S-Nitrosylation in Valosin-Containing Protein-Mediated Cardioprotection." Dissertation, Georgia State University, 2023.