Introduction
Materials and methods
Animals
Histopathology and mitochondrial ultrastructure
Myosin heavy-chain immunohistochemistry
Respiratory-chain enzyme activities
Serum parameters
Single-fiber mtDNA copy numbers
Microarray analysis
Statistics
Results
Zidovudine induces a respiratory-chain myopathy
Complete soleus muscle | Control (n= 10) | Zidovudine (n= 10) | P value | |||
---|---|---|---|---|---|---|
Soleus muscle fiber diameter (median μm) | 58.3 (IQR 54.2, 62.3) | 41.1 (IQR 37.5, 47.1) | <0.001 | |||
Serum creatine kinase (U/L) | 724 ± 480 | 548 ± 257 | 0.3 | |||
Serum creatinine (mg/L) | 3.6 ± 0.34 | 3.1 ± 0.11 | <0.001 | |||
Serum glucose (mg/L) | 1,760 ± 100 | 1,680 ± 220 | 0.055 | |||
Serum resting lactate (mM) | 4.5 ± 1.8 | 5.0 ± 1.6 | 0.9 | |||
Serum alanine aminotransferase (U/L) | 66 ± 8 | 56 ± 7 | 0.1 | |||
Serum aspartate aminotransferase (U/L) | 125 ± 35 | 101 ± 13 | 0.09 | |||
mtDNA copy number (mean copies/myonucleus) | 559 ± 46 | 399 ± 78 | <0.001 | |||
NADH DH (μmoles min-1 g muscle protein-1 ) | 684 ± 254 | 474 ± 236 | 0.042 | |||
COX (μmoles min-1 g muscle protein-1 ) | 28 ± 8 | 18 ± 9 | 0.026 | |||
SDH (μmoles min-1 g muscle protein-1 ) | 36 ± 6 | 35 ± 10 | 0.7 | |||
NADH DH/SDH-ratio (% of control mean) | 100 ± 28 | 72 ± 20 | 0.027 | |||
COX/SDH-ratio (% of control mean) | 100 ± 27 | 67 ± 26 | 0.016 | |||
Single-fiber soleus muscle | Control | Zidovudine | p-value | |||
Fiber type | Fast | Slow | Fast | Slow | Fast | Slow |
Fiber-type proportion (% of all fibers) | 5.2 ± 3.0 | 94.8 ± 3.0 | 13.3 ± 5.1 | 86.7 ± 5.1 | <0.001 | <0.001 |
Fiber diameter (mean μm) | 54.8 ± 5.8 | 65.5 ± 10.6 | 37.3 ± 9.3 | 51.8 ± 6.2 | <0.001 | 0.006 |
mtDNA copy number (mean copies/myonucleus) | 617 ± 91 | 683 ± 94 | 384 ± 91 | 206 ± 97 | <0.001 | <0.001 |
Type II fibers are enhanced in mitochondrial myopathy
Enhanced fast-fiber and repressed slow-fiber transcripts
Gene description (gene symbol) | FC | P value | qvalue |
---|---|---|---|
Respiratory chain complex I | |||
NADH dehydrogenase (ubiquinone) 1α subcomplex, 4 (Ndufa4) | -1.1 | 0.007 | 0.999 |
NADH dehydrogenase (ubiquinone) 1α/β subcomplex, 1 (Ndufab1) | 1.0 | 0.507 | 0.999 |
NADH dehydrogenase (ubiquinone) 1α subcomplex, assembly factor 1 (Ndufaf1) | -1.1 | 0.110 | 0.999 |
NADH dehydrogenase (ubiquinone) 1β subcomplex 3 (Ndufb3) | -1.0 | 0.772 | 0.999 |
NADH dehydrogenase (ubiquinone) 1β subcomplex, 5 (Ndufb5) | -1.1 | 0.036 | 0.999 |
NADH dehydrogenase (ubiquinone) 1 β subcomplex, 9 (Ndufb9) | -1.0 | 0.286 | 0.999 |
NADH dehydrogenase (ubiquinone) 1, subcomplex unknown, 1 (Ndufc1) | -1.1 | 0.167 | 0.999 |
NADH dehydrogenase (ubiquinone) Fe-S protein 1 (Ndufs1) | -1.1 | 0.045 | 0.999 |
NADH dehydrogenase subunit 1 (mt-ND1) | -1.1 | 0.267 | 0.999 |
NADH dehydrogenase subunit 2 (mt-ND2) | -1.1 | 0.087 | 0.999 |
NADH dehydrogenase subunit 4L (mt-ND4l) | -1.1 | 0.004 | 0.999 |
NADH dehydrogenase subunit 5 (mt-ND5) | -1.1 | 0.002 | 0.999 |
NADH dehydrogenase subunit 6 (mt-ND6) | -1.2 | 0.364 | 0.999 |
Respiratory chain complex II | |||
Succinate dehydrogenase complex, subunit B, iron sulfur (Ip) (Sdhb) | -1.4 | 0.00001 | 0.139 |
Respiratory chain complex III | |||
Ubiquinol-cytochrome c reductase binding protein (Uqcrb) | -1.1 | 0.003 | 0.999 |
Ubiquinol-cytochrome c reductase core protein I (Uqcrc1) | -1.0 | 0.677 | 0.999 |
Ubiquinol cytochrome c reductase core protein 2 (Uqcrc2) | -1.1 | 0.039 | 0.999 |
Respiratory chain complex IV | |||
Cytochrome c oxidase, subunit Va (Cox5a) | -1.1 | 0.205 | 0.999 |
Cytochrome c oxidase subunit Vb (Cox5b) | -1.0 | 0.442 | 0.999 |
Cytochrome c oxidase, subunit VIa, polypeptide 2 (Cox6a2) | -1.1 | 0.096 | 0.999 |
Cytochrome c oxidase, subunit VIc (Cox6c) | -1.1 | 0.144 | 0.999 |
Cytochrome c oxidase subunit VIIb (Cox7b) | 1.0 | 0.501 | 0.999 |
Cytochrome c oxidase, subunit VIIa 2 (Cox7a2) | -1.1 | 0.006 | 0.999 |
Cytochrome c oxidase subunit VIIa polypeptide 2 like (Cox7a2l) | -1.2 | 0.002 | 0.999 |
Cytochrome c oxidase subunit I (mt-Co1) | -1.1 | 0.000 | 0.999 |
Cytochrome c oxidase subunit II (mt-Co2) | -1.1 | 0.028 | 0.999 |
Respiratory chain complex V | |||
ATP synthase, F1 complex, γ polypeptide 1 (Atp5c1) | 1.0 | 0.807 | 0.999 |
ATP synthase, F0 complex, subunit C3 (subunit 9) (Atp5g3) | -1.1 | 0.080 | 0.999 |
ATP synthase GA binding protein transcription factor, α subunit: (Gabpa: Atp5j) | -1.2 | 0.005 | 0.999 |
ATP synthase, F0 complex, subunit F2 (Atp5j2) | 1.0 | 0.548 | 0.999 |
ATP synthase F0 subunit 6 (mt-atp6) | -1.3 | 0.739 | 0.999 |
ATP synthase F0 subunit 8 (mt-atp8) | -1.1 | 0.016 | 0.999 |
Glycolysis | |||
Phosphofructokinase, muscle (Pfkm) | 2.1 | 1.00E-35 | 1.00E-35 |
Pyruvate kinase, muscle (Pkm2) | 2.7 | 1.00E-35 | 1.00E-35 |
6-Phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (Pfkfb3) | 2.9 | 1.19E-13 | 3.26E-09 |
Glycogenolysis | |||
Phosphorylase, glycogen, muscle (Pygm) | 1.3 | 1.78E-14 | 4.88E-10 |
Phosphoglucomutase 1 (Pgm1) | 2.8 | 1.00E-35 | 1.00E-35 |
Phosphoglucomutase 2-like 1 (Pgm2l1) | 2.2 | 1.19E-13 | 3.25E-09 |
Fatty acid ß-oxidation | |||
Carnitine palmitoyltransferase 1b, muscle (CPT1b) | -1.4 | 3.52E-07 | 0.009 |
Hydroxyacyl-Coenzyme A dehydrogenase (Hadh) | -1.6 | 2.02E-07 | 0.005 |
Regulator genes (muscle fiber-type switch) | |||
SRY (sex-determining region Y)-box 6 (Sox6) | 5.2 | 1.00E-35 | 1.00E-35 |
Myogenic differentiation 1 (Myod1) | 4.4 | 1.11E-16 | 3.06E-12 |
Myogenin (Myog) | -3.7 | 1.78E-09 | 4.82E-05 |
Regulator of calcineurin 1 (Rcan1) | -4.6 | 3.51E-13 | 9.61E-09 |
SIX homeobox 1 (Six1) | 2.0 | 5.68E-12 | 1.55E-07 |
SIX homeobox 2 (Six2) | 5.0 | 9.39E-13 | 2.57E-08 |
Myostatin (Mstn) | 4.4 | 3.74E-13 | 1.03E-08 |
Estrogen-related receptor γ (Esrrg) | -2.1 | 1.07E-10 | 2.91E-06 |
NFAT activating protein with ITAM motif 1 (Nfam1) | -1.7 | 3.34E-08 | 8.96E-04 |