All Publications

  • Preclinical evaluation of genome-informed therapy for osteosarcoma using patient-derived xenografts Sayles, L., Breese, M., Koehne, A., Stan, L., Neyssa, M., Sheri, S., Alex, L., Spillinger, A., Dubois, S., Avedian, R., Hawkins, D., David, M., Sweet-Cordero, A. AMER ASSOC CANCER RESEARCH. 2018: 68
  • Mandibular odontoameloblastoma in a rat and a horse. Journal of veterinary diagnostic investigation Murphy, B., Bell, C., Koehne, A., Dubielzig, R. R. 2017: 1040638717711996-?


    Odontoameloblastoma (OA) is a mixed odontogenic tumor that is an ameloblastoma with concurrent histologic evidence of odontoma differentiation. As a mixed tumor, OA is a tripartite lesion comprised of neoplastic odontogenic epithelium, induced dental ectomesenchyme (dental pulp), and mineralized dental matrix. Although rare, OA represents a diagnostic conundrum, as it is histologically closely related to 2 other mixed odontogenic tumors: odontoma (complex and compound) and ameloblastic fibro-odontoma. Herein we describe an OA arising from the mandible of a 4-mo-old Fischer 344 rat that had been exposed in utero to the mutagen ENU (N-ethyl-N-nitrosourea), and a naturally occurring lesion in a 2-y-old Appaloosa horse. In order to satisfy the diagnostic criteria for this lesion, mineralized dental matrix in relationship to neoplastic odontogenic epithelium must be identifiable within the OA lesion. This group of odontogenic tumors is differentiated by the degree to which the dental matrix is organized and the relative proportions of pulp ectomesenchyme, odontogenic matrix, and odontogenic epithelium.

    View details for DOI 10.1177/1040638717711996

    View details for PubMedID 28545325

  • Influence of Genetic Background on Hematologic and Histopathologic Alterations during Acute Granulocytic Anaplasmosis in 129/SvEv and C57BL/6J Mice Lacking Type I and Type II Interferon Signaling COMPARATIVE MEDICINE Johns, J. L., Discipulo, M. L., Koehne, A. L., Moorhead, K. A., Nagamine, C. M. 2017; 67 (2): 127-137


    The role of host type I IFN signaling and its interaction with other immune pathways during bacterial infections is incompletely understood. Type II IFN signaling plays a key role during numerous bacterial infections including granulocytic anaplasmosis (GA) caused by Anaplasma phagocytophilum infection. The function of combined type I and type II IFN signaling and their potential synergism during GA and similar tick-borne diseases is a topic of current research investigation. The goal of this study was to evaluate 2 mouse models of absent type I/type II IFN signaling in experimental A. phagocytophilum infection to determine the effects of background strain. Mice lacking both type I and type II IFN receptor signaling (IFNAR-/-/IFNGR-/-) on either the 129/SvEv or C57BL/6J genetic background were evaluated at days 0, 6, 8, and 12 of infection. Pathogen burden in multiple organs was largely similar between strains of infected mice, with few significant differences. Background strain influenced the immune response to infection. Mice of the 129/SvEv strain developed more severe hematologic abnormalities, particularly more severe leukocytosis with marked neutrophilia and lymphocytosis, throughout acute infection. Histopathologic changes occurred in infected mice of both strains and varied in severity by organ. 129/SvEv mice developed more severe pathologic changes in spleen and bone marrow, whereas C57BL/6J mice developed more severe renal pathology. This work highlights the importance of mouse background strain in dictating pathophysiologic response to infection and informs future work regarding the loss of type I and type II IFN signaling on the immune response during GA.

    View details for Web of Science ID 000398880200006

    View details for PubMedID 28381313

  • Ectopic pregnancy with associated gestational choriocarcinoma in a California sea lion (Zalophus californianus) DISEASES OF AQUATIC ORGANISMS Fravel, V. A., Lowenstine, L. J., Koehne, A. 2016; 120 (2): 159-164


    A wild-born, captive-reared, 14 yr old, primiparous female California sea lion Zalophus californianus presented for anorexia of 14 d duration and abdominal distention. Routine complete blood cell count revealed leukocytosis with a neutrophilia, and serum chemistry revealed hypoalbumenemia and hyponatremia. Treatment with broad spectrum antibiotics and non-steroidal anti-inflammatories were started, but the animal continued to decline. Abdominal radiographs revealed a mature mineralized fetal skull and spine in the caudal abdomen and abdominal ultrasound revealed ascites but could not confirm the fetus. The patient was taken to surgery where a full term fetus was found outside of the uterus but within the fetal membranes, representing a secondary ectopic pregnancy. The patient passed away during surgery and was taken to necropsy. Gross necropsy revealed a diffuse peritonitis with yellow deposits over the serosal surfaces of the abdominal organs. The uterus appeared intact grossly and the ovaries appeared abnormal. The mesenteric, renal, and sub-lumbar nodes were enlarged and edematous. Histopathology revealed choriocarcinoma in the right uterine horn with evidence of chronic uterine rupture and protrusion of the placental tissue into the abdomen. The choriocarcinoma had metastasized locally as well as to the liver, spleen and lung. Choriocarcinoma is a highly malignant trophoblastic neoplasm that is rare in domestic animals. This case represents, to the authors' knowledge, the first report of gestational choriocarcinoma causing secondary ectopic pregnancy in a California sea lion and presents questions regarding pregnancy monitoring and management in a population of captive, minimally trained California sea lions.

    View details for DOI 10.3354/dao03014

    View details for Web of Science ID 000381105400007

    View details for PubMedID 27409239

  • Glucose Uptake and Intracellular pH in a Mouse Model of Ductal Carcinoma In situ (DCIS) Suggests Metabolic Heterogeneity. Frontiers in cell and developmental biology Lobo, R. C., Hubbard, N. E., Damonte, P., Mori, H., Pénzváltó, Z., Pham, C., Koehne, A. L., Go, A. C., Anderson, S. E., Cala, P. M., Borowsky, A. D. 2016; 4: 93-?


    Mechanisms for the progression of ductal carcinoma in situ (DCIS) to invasive breast carcinoma remain unclear. Previously we showed that the transition to invasiveness in the mammary intraepithelial neoplastic outgrowth (MINO) model of DCIS does not correlate with its serial acquisition of genetic mutations. We hypothesized instead that progression to invasiveness depends on a change in the microenvironment and that precancer cells might create a more tumor-permissive microenvironment secondary to changes in glucose uptake and metabolism. Immunostaining for glucose transporter 1 (GLUT1) and the hypoxia marker carbonic anhydrase 9 (CAIX) in tumor, normal mammary gland and MINO (precancer) tissue showed differences in expression. The uptake of the fluorescent glucose analog dye, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG), reflected differences in the cellular distributions of glucose uptake in normal mammary epithelial cells (nMEC), MINO, and Met1 cancer cells, with a broad distribution in the MINO population. The intracellular pH (pHi) measured using the fluorescent ratio dye 2',7'-bis(2-carboxyethyl)-5(6)-155 carboxyfluorescein (BCECF) revealed expected differences between normal and cancer cells (low and high, respectively), and a mixed distribution in the MINO cells, with a subset of cells in the MINO having an increased rate of acidification when proton efflux was inhibited. Invasive tumor cells had a more alkaline baseline pHi with high rates of proton production coupled with higher rates of proton export, compared with nMEC. MINO cells displayed considerable variation in baseline pHi that separated into two distinct populations: MINO high and MINO low. MINO high had a noticeably higher mean acidification rate compared with nMEC, but relatively high baseline pHi similar to tumor cells. MINO low cells also had an increased acidification rate compared with nMEC, but with a more acidic pHi similar to nMEC. These findings demonstrate that MINO is heterogeneous with respect to intracellular pH regulation which may be associated with an acidified regional microenvironment. A change in the pH of the microenvironment might contribute to a tumor-permissive or tumor-promoting progression. We are not aware of any previous work showing that a sub-population of cells in in situ precancer exhibits a higher than normal proton production and export rate.

    View details for DOI 10.3389/fcell.2016.00093

    View details for PubMedID 27630987

    View details for PubMedCentralID PMC5005977

  • The Influence of Dietary Fat Source on Life Span in Calorie Restricted Mice JOURNALS OF GERONTOLOGY SERIES A-BIOLOGICAL SCIENCES AND MEDICAL SCIENCES Lopez-Dominguez, J. A., Ramsey, J. J., Tran, D., Imai, D. M., Koehne, A., Laing, S. T., Griffey, S. M., Kim, K., Taylor, S. L., Hagopian, K., Villalba, J. M., Lopez-Lluch, G., Navas, P., McDonald, R. B. 2015; 70 (10): 1181-1188


    Calorie restriction (CR) without malnutrition extends life span in several animal models. It has been proposed that a decrease in the amount of polyunsaturated fatty acids (PUFAs), and especially n-3 fatty acids, in membrane phospholipids may contribute to life span extension with CR. Phospholipid PUFAs are sensitive to dietary fatty acid composition, and thus, the purpose of this study was to determine the influence of dietary lipids on life span in CR mice. C57BL/6J mice were assigned to four groups (a 5% CR control group and three 40% CR groups) and fed diets with soybean oil (high in n-6 PUFAs), fish oil (high in n-3 PUFAs), or lard (high in saturated and monounsaturated fatty acids) as the primary lipid source. Life span was increased (p < .05) in all CR groups compared to the Control mice. Life span was also increased (p < .05) in the CR lard mice compared to animals consuming either the CR fish or soybean oil diets. These results indicate that dietary lipid composition can influence life span in mice on CR, and suggest that a diet containing a low proportion of PUFAs and high proportion of monounsaturated and saturated fats may maximize life span in animals maintained on CR.

    View details for DOI 10.1093/gerona/glu177

    View details for Web of Science ID 000363481600002

    View details for PubMedID 25313149

    View details for PubMedCentralID PMC4612357

  • Japanese Bobtail: vertebral morphology and genetic characterization of an established cat breed JOURNAL OF FELINE MEDICINE AND SURGERY Pollard, R. E., Koehne, A. L., Peterson, C. B., Lyons, L. A. 2015; 17 (8): 719-726


    Several cat breeds are defined by morphological variation of the tail. The Japanese Bobtail is a breed that has been accepted for registration only within the past 50 years; however, the congenital kinked tail variants defining this breed were documented in the Far East centuries ago and the cats are considered 'good luck' in several Asian cultures. The recent discovery of the mutation for the tailless Manx phenotype has demonstrated that the Japanese Bobtail does not have a causative mutation in the same gene (T-Box). Here, a simple segregation analysis of cats bred from a pedigreed Japanese Bobtail demonstrated a simple autosomal dominant mode of inheritance with variable expression of the tail length and kink placement. Unexpectedly, radiological examinations of the entire vertebral column of kink-tailed cats indicated variation from the normal vertebral feline formula (C7, T13, L7, S3, Cd20-24), including cats with mostly one reduction of thoracic vertebrae (C7, T12, L7, S3), and an average of 15.8 caudal vertebrae. A few cats had variation in the number of cervical vertebrae. Several transitional vertebrae and anomalous ribs were noted. One cat had a bifid vertebra in the tail. Most cats had hemivertebrae that were usually included in the tail kink, one of which was demonstrated by gross pathology and histopathology. The abnormal vertebral formula or the placement of the kink in the tail did not coincide with morbidity or mortality.

    View details for DOI 10.1177/1098612X14558147

    View details for Web of Science ID 000358443100008

    View details for PubMedID 25488973

  • Factors influencing adverse skin responses in rats receiving repeated subcutaneous injections and potential impact on neurobehavior. Current neurobiology Levoe, S. N., Flannery, B. M., Brignolo, L., Imai, D. M., Koehne, A., Austin, A. T., Bruun, D. A., Tancredi, D. J., Lein, P. J. 2014; 5 (1-2): 1-10


    Repeated subcutaneous (s.c.) injection is a common route of administration in chronic studies of neuroactive compounds. However, in a pilot study we noted a significant incidence of skin abnormalities in adult male Long-Evans rats receiving daily s.c. injections of peanut oil (1.0 ml/kg) in the subscapular region for 21 d. Histopathological analyses of the lesions were consistent with a foreign body reaction. Subsequent studies were conducted to determine factors that influenced the incidence or severity of skin abnormalities, and whether these adverse skin reactions influenced a specific neurobehavioral outcome. Rats injected daily for 21 d with food grade peanut oil had an earlier onset and greater incidence of skin abnormalities relative to rats receiving an equal volume (1.0 ml/kg/d) of reagent grade peanut oil or triglyceride of coconut oil. Skin abnormalities in animals injected daily with peanut oil were increased in animals housed on corncob versus paper bedding. Comparison of animals obtained from different barrier facilities exposed to the same injection paradigm (reagent grade peanut oil, 1.0 ml/kg/d s.c.) revealed significant differences in the severity of skin abnormalities. However, animals from different barrier facilities did not perform differently in a Pavlovian fear conditioning task. Collectively, these data suggest that environmental factors influence the incidence and severity of skin abnormalities following repeated s.c. injections, but that these adverse skin responses do not significantly influence performance in at least one test of learning and memory.

    View details for PubMedID 25705100

    View details for PubMedCentralID PMC4334164

  • The Influence of Shc Proteins on Life Span in Mice JOURNALS OF GERONTOLOGY SERIES A-BIOLOGICAL SCIENCES AND MEDICAL SCIENCES Ramsey, J. J., Tran, D., Giorgio, M., Griffey, S. M., Koehne, A., Laing, S. T., Taylor, S. L., Kim, K., Cortopassi, G. A., Lloyd, K. C., Hagopian, K., Tomilov, A. A., Migliaccio, E., Pelicci, P. G., McDonald, R. B. 2014; 69 (10): 1177-1185


    The signaling molecule p66Shc is often described as a longevity protein. This conclusion is based on a single life span study that used a small number of mice. The purpose of the present studies was to measure life span in a sufficient number of mice to determine if longevity is altered in mice with decreased Shc levels (ShcKO). Studies were completed at UC Davis and the European Institute of Oncology (EIO). At UC Davis, male C57BL/6J WT and ShcKO mice were fed 5% or 40% calorie-restricted (CR) diets. In the 5% CR group, there was no difference in survival curves between genotypes. There was also no difference between genotypes in prevalence of neoplasms or other measures of end-of-life pathology. At 40% calorie restriction group, 70th percentile survival was increased in ShcKO, while there were no differences between genotypes in median or subsequent life span measures. At EIO, there was no increase in life span in ShcKO male or female mice on C57BL/6J, 129Sv, or hybrid C57BL/6J-129Sv backgrounds. These studies indicate that p66Shc is not a longevity protein. However, additional studies are needed to determine the extent to which Shc proteins may influence the onset and severity of specific age-related diseases.

    View details for DOI 10.1093/gerona/glt198

    View details for Web of Science ID 000343410000001

    View details for PubMedID 24336818

    View details for PubMedCentralID PMC4172037

  • To the Root of the Curl: A Signature of a Recent Selective Sweep Identifies a Mutation That Defines the Cornish Rex Cat Breed PLOS ONE Gandolfi, B., Alhaddad, H., Affolter, V. K., Brockman, J., Haggstrom, J., Joslin, S. E., Koehne, A. L., Mullikin, J. C., Outerbridge, C. A., Warren, W. C., Lyons, L. A. 2013; 8 (6)


    The cat (Felis silvestris catus) shows significant variation in pelage, morphological, and behavioral phenotypes amongst its over 40 domesticated breeds. The majority of the breed specific phenotypic presentations originated through artificial selection, especially on desired novel phenotypic characteristics that arose only a few hundred years ago. Variations in coat texture and color of hair often delineate breeds amongst domestic animals. Although the genetic basis of several feline coat colors and hair lengths are characterized, less is known about the genes influencing variation in coat growth and texture, especially rexoid - curly coated types. Cornish Rex is a cat breed defined by a fixed recessive curly coat trait. Genome-wide analyses for selection (di, Tajima's D and nucleotide diversity) were performed in the Cornish Rex breed and in 11 phenotypically diverse breeds and two random bred populations. Approximately 63K SNPs were used in the analysis that aimed to localize the locus controlling the rexoid hair texture. A region with a strong signature of recent selective sweep was identified in the Cornish Rex breed on chromosome A1, as well as a consensus block of homozygosity that spans approximately 3 Mb. Inspection of the region for candidate genes led to the identification of the lysophosphatidic acid receptor 6 (LPAR6). A 4 bp deletion in exon 5, c.250_253_delTTTG, which induces a premature stop codon in the receptor, was identified via Sanger sequencing. The mutation is fixed in Cornish Rex, absent in all straight haired cats analyzed, and is also segregating in the German Rex breed. LPAR6 encodes a G protein-coupled receptor essential for maintaining the structural integrity of the hair shaft; and has mutations resulting in a wooly hair phenotype in humans.

    View details for DOI 10.1371/journal.pone.0067105

    View details for Web of Science ID 000321150000027

    View details for PubMedID 23826204

    View details for PubMedCentralID PMC3694948

  • Selective Kv1.3 channel blocker as therapeutic for obesity and insulin resistance PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Upadhyay, S. K., Eckel-Mahan, K. L., Mirbolooki, M. R., Tjong, I., Griffey, S. M., Schmunk, G., Koehne, A., Halbout, B., Iadonato, S., Pedersen, B., Borrelli, E., Wang, P. H., Mukherjee, J., Sassone-Corsi, P., Chandy, K. G. 2013; 110 (24): E2239-E2248


    Obesity is an epidemic, calling for innovative and reliable pharmacological strategies. Here, we show that ShK-186, a selective and potent blocker of the voltage-gated Kv1.3 channel, counteracts the negative effects of increased caloric intake in mice fed a diet rich in fat and fructose. ShK-186 reduced weight gain, adiposity, and fatty liver; decreased blood levels of cholesterol, sugar, HbA1c, insulin, and leptin; and enhanced peripheral insulin sensitivity. These changes mimic the effects of Kv1.3 gene deletion. ShK-186 did not alter weight gain in mice on a chow diet, suggesting that the obesity-inducing diet enhances sensitivity to Kv1.3 blockade. Several mechanisms may contribute to the therapeutic benefits of ShK-186. ShK-186 therapy activated brown adipose tissue as evidenced by a doubling of glucose uptake, and increased β-oxidation of fatty acids, glycolysis, fatty acid synthesis, and uncoupling protein 1 expression. Activation of brown adipose tissue manifested as augmented oxygen consumption and energy expenditure, with no change in caloric intake, locomotor activity, or thyroid hormone levels. The obesity diet induced Kv1.3 expression in the liver, and ShK-186 caused profound alterations in energy and lipid metabolism in the liver. This action on the liver may underlie the differential effectiveness of ShK-186 in mice fed a chow vs. an obesity diet. Our results highlight the potential use of Kv1.3 blockers for the treatment of obesity and insulin resistance.

    View details for DOI 10.1073/pnas.1221206110

    View details for Web of Science ID 000320930100014

    View details for PubMedID 23729813

    View details for PubMedCentralID PMC3683782

  • Mutant mice derived by ICSI of evaporatively dried spermatozoa exhibit expected phenotype REPRODUCTION Li, M., Baridon, B., Trainor, A., Djan, E., Koehne, A., Griffey, S. M., Biggers, J. D., Toner, M., Lloyd, K. C. 2012; 143 (4): 449-453


    Apolipoprotein E (Apoe)-deficient knockout mice were used to test the hypothesis that mutant mice preserved as evaporatively dried (ED) spermatozoa, stored at -80 °C for 6 months, and then recovered by ICSI will exhibit the same phenotype as before preservation. The birth rate of mice recovered by ICSI of evaporatively dried spermatozoa was lower than that of fresh spermatozoa (17.5 vs 38.0%). Progeny of mice preserved using evaporatively dried spermatozoa were reproductively sound. From these, the second generation of mice produced by natural mating showed lesions typical of APOE deficiency, including severe hypercholesterolemia, hypertriglyceridemia, markedly increased plasma low-density lipoprotein level, and extensive and severe atherosclerotic lesions in the aorta. We conclude that the expected phenotype caused by an induced genetic mutation can be faithfully recapitulated and sustained in subsequent generations of mice preserved and stored as ED spermatozoa and recovered using ICSI. Because it is simpler, faster, and cheaper than conventional (cryopreservation) and nonconventional (freeze-drying) preservation procedures, evaporative drying is a viable, cost-effective, and efficient method for preserving and storing valuable mutant mouse strains.

    View details for DOI 10.1530/REP-12-0005

    View details for Web of Science ID 000302956600004

    View details for PubMedID 22274886

    View details for PubMedCentralID PMC3738174