Here, we present a modification of a previously reported method that allows for the isolation of high quality and purified mitochondria from smaller quantities of mouse skeletal muscle. This procedure results in highly coupled mitochondria that respire with high function during microplate based respirometirc assays.
Dysfunksjonelle skjelettmuskel mitokondrier spille en rolle i endret metabolisme observert med aldring, overvekt og type II diabetes. Mitokondrie respirometrisk analysene fra preparater av isolerte mitokondrier tillate vurdering av mitokondriell funksjon, så vel som bestemmelse av mekanismen (e) av virkningen av narkotika og proteiner som modulerer metabolisme. Nåværende isoleringsprosedyrer krever ofte store mengder av vev for å gi høy kvalitet mitokondrier er nødvendige for respirometrisk analyser. Metodene som presenteres heri beskriver hvordan høy kvalitet renset mitochondria (~ 450 ug) kan isoleres fra minimale mengder (~ 75 til 100 mg) av mus skjelettmuskulatur for anvendelse ved høy gjennomstrømning respirasjonsmålinger. Vi fastslått at vår isolasjonsmetoden gir 92,5 ± 2,0% intakt mitokondriene ved å måle citratsyntaseaktivitet spektrofotometrisk. I tillegg, Western blot-analyse i isolerte mitokondrier resulterte i svak ekspresjon av cytosolic protein, GAPDH og robust uttrykk for mitokondrie protein, COXIV. Fraværet av en fremtredende GAPDH bånd i de isolerte mitokondrier er indikativ for lite forurensning fra ikke-mitokondrielle kilder under isoleringsprosedyren. Viktigst, måling av O 2 forbruk hastighet med micro-plate basert teknologi og bestemme luftkontrollforholdet (RCR) for koblede respirometrisk analyser viser svært kombinert (RCR;> 6 for alle analyser) og funksjonelle mitokondrier. Som konklusjon, tilsetning av et separat hakking trinn og betydelig redusere motordrevet homogenisering hastigheten til en tidligere rapportert fremgangsmåte har tillatt isoleringen av høy kvalitet og renset mitokondrier fra mindre mengder av mus skjelettmuskulatur som resulterer i sterkt koplet mitokondrier som respirere med høy funksjon under mikro basert respirometirc analyser.
The primary function of mitochondria is to produce ATP from oxidative phosphorylation. However, mitochondria have many other important cellular functions including but not limited to: the production and detoxification of reactive oxygen species, the regulation of cytoplasmic and mitochondrial calcium, organelle trafficking, ionic homeostasis, and involvement in apoptosis1,2. Therefore, it is not surprising that dysfunctional mitochondria play a role in many disease pathologies, such as aging, neurodegenerative diseases, cardiovascular disease, cancer, obesity, and diabetes3,4. Importantly, skeletal muscle mitochondria specifically are involved in many of these pathologies3-5.
Mitochondrial respiration assays using isolated mitochondria allow for the assessment of electron transport chain and oxidative phosphorylation function, and the determination of mechanism(s) of action of drugs and proteins that modulate metabolism. Mitochondrial isolation procedures exist for multiple tissue and cell types for a variety of species6,7. However, these procedures often require large quantities of tissue/cells for a high quality mitochondria yield necessary for classic respirometric assays.
Microplate based respirometirc assays allow for high throughput measurements using minimal quantities of isolated mitochondria, often just several µg per well8. Therefore, we present a modification of previously published methods7 to allow for high quality mitochondria to be isolated from smaller quantities of mouse skeletal muscle for use in microplate based respirometirc assays. In addition, methods are provided to establish the quality of the mitochondrial isolation preparation and the integrity of the mitochondrial membranes. Given that skeletal muscle mitochondria are involved in many pathological conditions, the measurement of O2 consumption in mechanistically driven studies is becoming more prevalent in biomedical research9,10.
Metodene som presenteres heri, gir en detaljert beskrivelse av en mitokondriell isoleringsprosedyren fra minimale mengder (~ 75 til 100 mg) av mus skjelettmuskel. Denne isolasjonen prosedyren er i stand til å gi høyt fungerende, ren mitokondrier (~ 450 mikrogram) som gjenspeiles av O 2 forbruk priser, RCR verdier, maksimal citratsyntaseaktivitet og protein expression fra immunoblotting. Viktigere, kan mitokondriene isolert fra denne fremgangsmåten kan brukes for flere respirometirc analyser med mikroplateb…
The authors have nothing to disclose.
The Fralin Life Science Research Institute and The Metabolic Phenotyping Core at Virginia Tech supported this work.
Essentially Fatty | Sigma Aldrich | A6003 | N/A |
Acid Free- BSA | |||
Tris/HCl | Promega | H5123 | N/A |
KCL | Sigma Aldrich | P9541 | N/A |
Tris Base | Promega | H5135 | N/A |
EDTA | Sigma Aldrich | E6511 | N/A |
EGTA | Sigma Aldrich | E4378 | N/A |
Sucrose | Sigma Aldrich | S7903 | N/A |
D-Mannitol | Sigma Aldrich | 63559 | N/A |
Trypsin-EDTA (0.25%), phenol red | Thermo Scientific | 25200-056 | N/A |
Sodium Chloride White Crystals or Crystalline Powder ≥99.0 % |
Fisher Scientific | BP3581 | N/A |
Sodium dodecyl sulfate | Sigma Aldrich | L3771 | N/A |
Sodium deoxycholate | Sigma Aldrich | D6750 | N/A |
Polyoxyethylene (12) nonylphenyl ether, branched | Sigma Aldrich | 238651 | N/A |
Single Edge Razor Blades | Fisher Scientific | 12-640 | N/A |
Falcon- 100 uM Nylon Cell Strainers | Fisher Scientific | 352360 | N/A |
Halt Protease & Phosphatse Inhibitor Cocktail | Thermo Scientific | 1861284 | N/A |
1.5mL microcentrifuge tubes with screw cap | Thermo Scientific | 3474 | N/A |
Zirconium Oxide beads | Fisher Scientific | C9012112 | N/A |
GAPDH antibody (1D4) | Santa Cruz Biotechnology | sc-59540 | N/A |
Anti- COXIV antibody | Cell Signaling | 4844s | Any mitochondrial inner membrane protein will suffice |
Peroxidase conjugated affinipure Donkey, Anti Rabbit IgG (H+L) | Jackson ImmunoResearh | 711-035-152 | N/A |
Peroxidase conjugated affinipure Goat, Anti Mouse IgG (H+L) | Jackson ImmunoResearh | 115-001-003 | N/A |
Triton-X100 | Sigma Aldrich | X100 | N/A |
Pierce BCA Protein Assay Kit | Thermo Scientific | 23225 | N/A |
Pyruvic Acid, 98% | Sigma Aldrich | 107360 | Store at 4°C,pH to 7.4 with KOH prior to use in respirometric assay |
Succinic Acid | Sigma Aldrich | S9512 | Store at room temperature, pH to 7.4 with KOH prior to use in respirometric assay |
L(-) Malic Acid, BioXtra, ≥95% | Sigma Aldrich | M6413 | Store at room temperature, to 7.4 with KOH prior to use in respirometric assay |
L-Glutamic acid | Sigma Aldrich | G1251 | Store at room temperature, to 7.4 with KOH prior to use in respirometric assay, to 7.4 with KOH prior to use in respirometric assay |
Palmitoyl L-carnitine chloride | Sigma Aldrich | P1645 | Store at -20°C |
Oligomycin A, ≥ 95% (HPLC) | Sigma Aldrich | 75351 | Store at -20°C |
Carbonyl cyanide 4-(trifluoromethoxy) | Sigma Aldrich | C2920 | Store at 2-8°C |
phenylhydrazone | |||
≥98% (TLC), powder [FCCP] | |||
Antimycin A from streptomyces sp. | Sigma Aldrich | A8674 | Store at -20°C |
Adenosine 5′-diphosphate monopotassium salt dehydrate [ADP] | Sigma Aldrich | A5285 | Store at -20°C, to 7.4 with KOH prior to use in respirometric assay |
Rotenone | Sigma Aldrich | R8875 | Store at room temperature |