title: Ciprofloxacin Therapy Results in Mitigation of ATP Loss after Irradiation Combined with Wound Trauma: Preservation of Pyruvate Dehydrogenase and Inhibition of Pyruvate Dehydrogenase Kinase 1.
abstract: Ionizing radiation exposure combined with wound injury increases animal mortalities than ionizing radiation exposure alone. Ciprofloxacin (CIP) is in the fluroquinolone family of synthetic antibiotic that are available from the strategic national stockpile for emergency use and is known to inhibit bacterial sepsis. The purpose of this study was to evaluate the efficacy of ciprofloxacin as a countermeasure to combined injury mortality and determine the signaling proteins involved in energy machinery. B6D2F1/J female mice were randomly assigned to receive either 9.75 Gy irradiation with Co-60 gamma rays followed by skin wounding (combined injury; CI) or sham procedure (sham). Either ciprofloxacin (90 mg/kg/day) or vehicle (VEH) (water) was administered orally to these mice 2 h after wounding and thereafter daily for 10 days. Determination of tissue adenosine triphosphate (ATP) was conducted, and immunoblotting for signaling proteins involved in ATP machinery was performed. Combined injury resulted in 60% survival after 10 days compared to 100% survival in the sham group. Furthermore, combined injury caused significant reductions of ATP concentrations in ileum, pancreas, brain, spleen, kidney and lung (-25% to -95%) compared to the sham group. Ciprofloxacin administration after combined injury resulted in 100% survival and inhibited reductions in ileum and kidney ATP production. Ileum protein levels of heat-shock protein 70 kDa (HSP-70, a chaperone protein involved in ATP synthesis) and pyruvate dehydrogenase (PDH, an enzyme complex crucial to conversion of pyruvate to acetyl CoA for entrance into TCA cycle) were significantly lower in the CI group (vs. sham group). Using immunoprecipitation and immunoblotting, HSP-70-PDH complex was found to be present in the ileum tissue of CI mice treated with ciprofloxacin. Furthermore, phosphorylation of serine residues of PDH resulting in inactivating PDH enzymatic activity, which occurred after combined injury, was inhibited with ciprofloxacin treatment, thus enabling PDH to increase ATP production. Increased ileum levels of pyruvate dehydrogenase kinase 1 protein (PDK1, an enzyme responsible for PDH phosphorylation) after combined injury were also prevented by ciprofloxacin treatment. Taken together, these data suggest that ciprofloxacin oral administration after combined injury had a role in sustained ileum ATP levels, and may have acted through preservation of PDH by HSP-70 and inhibition of PDK1. These molecular changes in the ileum are simply one of a host of mechanisms working in concert with one another by which ciprofloxacin treatment mitigates body weight loss and drastically enhances subsequent survival after combined injury. To this end, our findings indicate that oral treatment of ciprofloxacin is a valuable therapeutic treatment after irradiation with combined injury and warrants further analyses to elucidate the precise mechanisms involved.
authors.affiliation: a  Armed Forces Radiobiology Research Institute, Bethesda, Maryland 20889; and.|b  Departments of Military and Emergency Medicine;|c  Radiation Biology and.
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Swift
authors.affiliation: a  Armed Forces Radiobiology Research Institute, Bethesda, Maryland 20889; and.
authors.forename: Joan T
authors.initials: JT
authors.lastname: Smith
authors.affiliation: a  Armed Forces Radiobiology Research Institute, Bethesda, Maryland 20889; and.|c  Radiation Biology and.|d  Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814.
authors.forename: Juliann G
authors.initials: JG
authors.lastname: Kiang
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000284:Administration, Oral; D000818:Animals; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D005720:Gamma Rays / Q000009:adverse effects; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D007082:Ileum / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects / Q000528:radiation effects; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism*; D011833:Radiation Injuries, Experimental / Q000150:complications* / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D014947:Wounds and Injuries / Q000150:complications*
chemical_list: D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; C000631433:Pdk1 protein, mouse; D047428:Protein Kinase Inhibitors; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D011768:Pyruvate Dehydrogenase Complex; D012694:Serine; D002939:Ciprofloxacin; D000255:Adenosine Triphosphate; D017346:Protein Serine-Threonine Kinases