Liver biomarker and in vitro assessment confirm the hepatic origin of aminotransferase elevations lacking histopathological correlate in beagle dogs treated with GABAA receptor antagonist NP260.
NP260 was designed as a first-in-class selective antagonist of α4-subtype GABAA receptors that had promising efficacy in animal models of pain, epilepsy, psychosis, and anxiety. However, development of NP260 was complicated following a 28-day safety study in dogs in which pronounced elevations of serum aminotransferase levels were observed, although there was no accompanying histopathological indication of hepatocellular injury. To further investigate the liver effects of NP260, we assayed stored serum samples from the 28-day dog study for liver specific miRNA (miR-122) as well as enzymatic biomarkers glutamate dehydrogenase and sorbitol dehydrogenase, which indicate liver necrosis. Cytotoxicity assessments were conducted in hepatocytes derived from dog, rat, and human liver samples to address the species specificity of the liver response to NP260. All biomarkers, except ALT, returned toward baseline by Day 29 despite continued drug treatment, suggesting adaptation to the initial injury. In vitro analysis of the toxicity potential of NP260 to primary hepatocytes indicated a relative sensitivity of dog>human>rat, which may explain, in part, why the liver effects were not evident in the rodent safety studies. Taken together, the data indicate that a diagnostic biomarker approach, coupled with sensitive in vitro screening strategies, may facilitate interpretation of toxicity potential when an adaptive event masks the underlying toxicity.
College of Public Health, The University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA; The Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709, USA. Electronic address: ahharrill@uams.edu.
Alison H
AH
Harrill
The Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709, USA.
John S
JS
Eaddy
The Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709, USA.
Kelly
K
Rose
College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA.
John M
JM
Cullen
QPS, Newark, DE 19711, USA.
Lakshmi
L
Ramanathan
NeuroTherapeutics Pharma, Inc., Chicago, IL 60631, USA.
Stephen
S
Wanaski
NeuroTherapeutics Pharma, Inc., Chicago, IL 60631, USA.
Stephen
S
Collins
NeuroTherapeutics Pharma, Inc., Chicago, IL 60631, USA.
Yu
Y
Ho
The Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709, USA; Schools of Pharmacy and Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Paul B
PB
Watkins
The Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709, USA.
Edward L
EL
Lecluyse
D000255:Adenosine Triphosphate / Q000378:metabolism; D000410:Alanine Transaminase / Q000097:blood*; D000818:Animals; D015415:Biomarkers / Q000097:blood; D002478:Cells, Cultured; D056486:Chemical and Drug Induced Liver Injury / Q000097:blood / Q000175:diagnosis / Q000209:etiology* / Q000235:genetics; D004796:Clinical Enzyme Tests; D004285:Dogs; D005260:Female; D058787:GABA-A Receptor Antagonists / Q000633:toxicity*; D005819:Genetic Markers; D005969:Glutamate Dehydrogenase / Q000097:blood; D022781:Hepatocytes / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D006801:Humans; D007064:L-Iditol 2-Dehydrogenase / Q000097:blood; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008297:Male; D035683:MicroRNAs / Q000097:blood; D009336:Necrosis; D011237:Predictive Value of Tests; D051381:Rats; D017207:Rats, Sprague-Dawley; D018570:Risk Assessment; D013045:Species Specificity; D013450:Sulfones / Q000633:toxicity*; D013997:Time Factors; D018675:Toxicity Tests / Q000379:methods*; D062368:meta-Aminobenzoates / Q000633:toxicity*
D015415:Biomarkers; D058787:GABA-A Receptor Antagonists; D005819:Genetic Markers; D035683:MicroRNAs; C000589285:NP260; D013450:Sulfones; D062368:meta-Aminobenzoates; D000255:Adenosine Triphosphate; D007064:L-Iditol 2-Dehydrogenase; D005969:Glutamate Dehydrogenase; D000410:Alanine Transaminase
Biomarker; Canine; GLDH; Hepatic; Hepatotoxicity; Liver; SDH; miR-122; miRNA