Shane E Kruse

University of Washington Seattle | UW · Department of Radiology

Significance Mitochondria meet the majority of living cells’ demand for ATP and, as important regulators of redox homeostasis, metabolite levels, and calcium buffering, are a critical link between cell energetics and signaling. Disruption of these processes can induce adaptive or pathological signaling responses to stress and under severe stress pr...

Fig. S1 Protein half‐life is modified with age and is dependent on muscle type (B). Fig. S2 EDL and SOL Tissue Weights. Fig. S3 Minimal Inverse Correlation between Protein Abundance and Half‐life. Fig. S4 Oxidative State of Skeletal Muscle: Muscle Fiber H2O2 Production, Protein Carbonyl content and GSH‐modified Proteins. Table S1 Ingenuity Path...

Changes in mitochondrial function with age vary between different muscle types, and mechanisms underlying this variation remain poorly defined. We examined whether the rate of mitochondrial protein turnover contributes to this variation. Using heavy label proteomics, we measured mitochondrial protein turnover and abundance in slow-twitch soleus (SO...

The mitochondrial respiratory chain (RC) produces most of the cellular ATP and requires strict quality-control mechanisms. To examine RC subunit proteostasis in vivo, we measured RC protein half-lives (HLs) in mice by liquid chromatography-tandem mass spectrometry with metabolic [(2)H3]-leucine heavy isotope labeling under divergent conditions. We...

Mitochondrial dysfunction plays a key pathogenic role in aging skeletal muscle resulting in significant healthcare costs in the developed world. However, there is no pharmacologic treatment to rapidly reverse mitochondrial deficits in the elderly. Here we demonstrate that a single treatment with the mitochondrial targeted peptide SS-31 restores in...

Anesthetics are in routine use, yet the mechanisms underlying their function are incompletely understood. Studies in vitro demonstrate that both GABA(A) and NMDA receptors are modulated by anesthetics, but whole animal models have not supported the role of these receptors as sole effectors of general anesthesia. Findings in C. elegans and in childr...

Leigh syndrome (LS) is a subacute necrotizing encephalomyelopathy with gliosis in several brain regions that usually results in infantile death. Loss of murine Ndufs4, which encodes NADH dehydrogenase (ubiquinone) iron-sulfur protein 4, results in compromised activity of mitochondrial complex I as well as progressive neurodegenerative and behaviora...

Intracellular amyloid beta (Aβ) oligomers and extracellular Aβ plaques are key players in the progression of sporadic Alzheimer's disease (AD). Still, the molecular signals triggering Aβ production are largely unclear. We asked whether mitochondrion-derived reactive oxygen species (ROS) are sufficient to increase Aβ generation and thereby initiate...

Functional classification of genes differentially regulated in SOD1−/− mice. Bars show the percentage of genes in the GO categories significantly overrepresented in the genes over expressed (A) or under expressed (B) in SOD1−/− relative to WT in the EDL muscle using the GO FAT categories in NIH DAVID. Dark bars indicate categories associated with m...

Heart rate (A) and arterial hemoglobin oxygen saturation (B) were measured before (0 days), after one week (7 days) and following two weeks of PQ treatment (14 days). There was no significant effect of PQ treatment on either variable at any time point. Data means±SEM, n = 5. (TIF)

List of genes differentially expressed in the EDL of SOD1−/− mice compared to WT. Genes are grouped into those uregulated and downregulated in SOD1−/− and sorted by false discovery rate adjusted p-value (fdr_p). All genes are p<0.05. (XLS)

(A) A significant decrease in resting myoglobin (Mb) saturation with PQ treatment indicates an increased mitochondrial demand on oxygen delivery systems with uncoupling. n = 8–9, * p<0.05. (B) There is a significant negative correlation between resting myoglobin saturation and in vivo mitochondrial oxygen consumption in PQ mice (p<0.0001). (TIF)

Oxidative stress has the same effect on the in vivo metabolism of male mice as female mice. Treatment with 20 mg/kg PQ per week for two weeks leads to (A) decreased coupling of oxidative phosphorylation as measured by P/O ratio and (B) increased energy stress as measured by PCr/ATP ratio in male mice. Data means±SEM, n = 3, * p<0.05. (TIF)

The absence of SOD1 leads to an increase in oxidative stress in skeletal muscle, as measured by F2-Isoprostanes in the gastrocnemius of female SOD1−/− mice. Data means±SEM, n = 4, * p<0.05. Significance determined using one-tailed t-test. (TIF)

NIH DAVID Functional classification of genes listed in Table S1. GO categories containing more than five members with p<0.05 are listed. All categories, including redundant categories, are listed in the table. Data in the % column was used to generate Figure S5. (XLS)

Detailed explanation of methods used to acquire data presented in Figures S1 and S5 and Tables S1 and S2. (DOC)

Oxidative stress and mitochondrial function are at the core of many degenerative conditions. However, the interaction between oxidative stress and in vivo mitochondrial function is unclear. We used both pharmacological (2 week paraquat (PQ) treatment of wild type mice) and transgenic (mice lacking Cu, Zn-superoxide dismutase (SOD1(-/-))) models to...

Mitochondrial complex I (CI) is a multi-subunit enzyme that forms the major entry point of nicotinamide adenine dinucleotide (NADH) electrons into the respiratory chain. Mutations in the NDUFS4 gene, encoding an accessory subunit of this complex, cause a Leigh-like phenotype in humans. To study the nature and penetrance of the CI defect in differen...

To explore the lethal, ataxic phenotype of complex I deficiency in Ndufs4 knockout (KO) mice, we inactivated Ndufs4 selectively in neurons and glia (NesKO mice). NesKO mice manifested the same symptoms as KO mice including retarded growth, loss of motor ability, breathing abnormalities, and death by approximately 7 wk. Progressive neuronal deterior...

Inhibition of mitochondrial complex I is one of the leading hypotheses for dopaminergic neuron death associated with Parkinson's disease (PD). To test this hypothesis genetically, we used a mouse strain lacking functional Ndufs4, a gene encoding a subunit required for complete assembly and function of complex I. Deletion of the Ndufs4 gene abolishe...

To study effects of mitochondrial complex I (CI, NADH:ubiquinone oxidoreductase) deficiency, we inactivated the Ndufs4 gene, which encodes an 18 kDa subunit of the 45-protein CI complex. Although small, Ndufs4 knockout (KO) mice appeared healthy until approximately 5 weeks of age, when ataxic signs began, progressing to death at approximately 7 wee...

As dysfunction of cerebral cholinergic neurotransmission is one of the main features in patients with Alzheimer's disease, in vivo imaging of the vesicular acetylcholine transporter (VAChT) can be of great value for the early diagnosis of this disease. Two series of positional isomers of m-iodobenzyltrozamicol (MIBT): 3-hydroxy-4-(N-phenylpiperazin...

Our goal was to synthesize new stereospecific benzovesamicol analogues, which could potentially be used as SPECT or PET radioligands for the vesicular acetylcholine transporter (VAChT). This paper describes the chemical synthesis, resolution and determination of binding affinity for four enantiomeric pairs of derivatives. Their intrinsic affinities...