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Bruton's tyrosine kinase (BTK) is a member of the Tec family of cytoplasmic tyrosine kinases involved in B-cell and myeloid cell signaling. Small molecule inhibitors of BTK are being investigated for treatment of several hematologic cancers and autoimmune diseases. GDC-0853 ((S)-2-(3'-(hydroxymethyl)-1-methyl-5-((5-(2-methyl-4-(oxetan-3-yl)piperazin-1-yl)pyridin-2-yl)amino)-6-oxo-1,6-dihydro-[3,4'-bipyridin]-2'-yl)-7,7-dimethyl-3,4,7,8-tetrahydro-2H-cyclopenta[4,5]pyrrolo[1,2-a]pyrazin-1(6H)-one) is a selective and reversible oral small-molecule BTK inhibitor in development for the treatment of rheumatoid arthritis and systemic lupus erythematosus. In Sprague-Dawley (SD) rats, administration of GDC-0853 and other structurally diverse BTK inhibitors for 7 days or longer caused pancreatic lesions consisting of multifocal islet-centered hemorrhage, inflammation, fibrosis, and pigment-laden macrophages with adjacent lobular exocrine acinar cell atrophy, degeneration, and inflammation. Similar findings were not observed in mice or dogs at much higher exposures. Hemorrhage in the peri-islet vasculature emerged between four and seven daily doses of GDC-0853 and was histologically similar to spontaneously occurring changes in aging SD rats. This suggests that GDC-0853 could exacerbate a background finding in younger animals. Glucose homeostasis was dysregulated following a glucose challenge; however, this occurred only after 28 days of administration and was not directly associated with onset or severity of pancreatic lesions. There were no changes in other common serum biomarkers assessing endocrine and exocrine pancreatic function. Additionally, these lesions were not readily detectable via Doppler ultrasound, computed tomography, or magnetic resonance imaging. Our results indicate that pancreatic lesions in rats are likely a class effect of BTK inhibitors, which may exacerbate an islet-centered pathology that is unlikely to be relevant to humans.

Dilated cardiomyopathy recently has been recognized in juvenile Portuguese Water Dogs. The purpose of this study was to evaluate unaffected and affected puppies by physical examination, electrocardiogram (ECG), echocardiogram, specific biochemical assays, and ultrastructure to document disease progression and to develop a method of early detection. Results of segregation analysis were consistent with autosomal recessive inheritance. Of 124 puppies evaluated clinically and echocardiographically, 10 were affected. No significant differences were found between unaffected and affected puppies for blood and myocardial carnitine or taurine concentrations, serum chemical variables, results of ophthalmological examinations, ECGs, or measurement of urine metabolites. Ultrastructural examination of myocardium from affected dogs revealed myofibrillar atrophy and small regions of myo‐fibrillar degeneration, most prominently at the region of the intercalated discs. Only echocardiography allowed detection of affected puppies before clinical signs became evident. Echocardiography revealed a significant difference in the shortening fraction, E point to septal separation, and the end systolic and diastolic left ventricular internal diameters. Affected puppies were detected 1–4 weeks before the development of acute congestive heart failure.

Inosine monophosphate dehydrogenase (IMPDH), a key enzyme in the de novo synthesis of guanosine nucleotides, catalyzes the irreversible nicotinamide-adenine dinucleotide dependent oxidation of inosine-5'-monophosphate to xanthosine-5'-monophosphate. Mycophenolate Mofetil (MMF), a prodrug of mycophenolic acid, has clinical utility for the treatment of transplant rejection based on its inhibition of IMPDH. The overall clinical benefit of MMF is limited by what is generally believed to be compound-based, dose-limiting gastrointestinal (GI) toxicity that is related to its specific pharmacokinetic characteristics. Thus, development of an IMPDH inhibitor with a novel structure and a different pharmacokinetic profile may reduce the likelihood of GI toxicity and allow for increased efficacy. This article will detail the discovery and SAR leading to a novel and potent acridone-based IMPDH inhibitor 4m and its efficacy and GI tolerability when administered orally in a rat adjuvant arthritis model.

Inhibitors of p38 MAP kinases show promise for the treatment of inflammatory and immunological disorders and some cancers. There is a substantial body of experimental evidence across several organ systems suggesting that p38 also mediates developmental, differentiation and proliferation processes. As a consequence of the wide-ranging regulatory role of p38 kinase in diverse cellular processes, the possibility of adverse events resulting from undesired pharmacological activity is a major concern for the p38 inhibitor drug class. Taking into consideration the limitations of experimental modeling systems, together the data may indicate that profound inhibition of p38 has the potential to impact these processes during fetal or neonatal development. The difficulty comes in extrapolating these findings to predict potential adverse effects under conditions of partial inhibition of p38 activity, and in an adult population in which these processes are typically only recapitulated during repair or adaptive responses. As such, the goal of this review of the targets of p38 activity is to bring an awareness of the those organ systems that should be monitored for potential toxicity, as well as to present a potential mechanistic basis for such monitoring or for investigation of adverse effects that may develop with administration of a p38 inhibitor.

Discovery of novel protein biomarkers is essential for successful drug discovery and development. These novel protein biomarkers may aid accelerated drug efficacy, response, or toxicity decision making based on their enhanced sensitivity and/or specificity. These biomarkers, if necessary, could eventually be converted into novel diagnostic marker assays. Proteomic platforms developed over the past few years have given us the ability to rapidly identify novel protein biomarkers in various biological matrices from cell cultures (lysates, supernatants) to human clinical samples (serum, plasma, and urine). In this article, we delineate an approach to biomarker discovery. This approach is divided into three steps, (i) identification of markers, (ii) prioritization of identified markers, and (iii) preliminary validation (qualification) of prioritized markers. Using drug-induced idiosyncratic hepatotoxicity as a case study, the article elaborates methods and techniques utilized during the three steps of biomarker discovery process. The first step involves identification of markers using multi-dimensional protein identification technology. The second step involves prioritization of a subset of marker candidates based on several criteria such as availability of reagent set for assay development and literature association to disease biology. The last step of biomarker discovery involves development of preliminary assays to confirm the bio-analytical measurements from the first step, as well as qualify the marker(s) in pre-clinical models, to initiate future marker validation and development.

Glomerular disease was diagnosed by histopathologic examination in 11 related Bullmastiff dogs, and clinical and laboratory data were collected retrospectively. Four female and seven male dogs between the ages of 2.5 and 11 years were affected. Clinical signs, including lethargy and anorexia, were nonspecific and occurred shortly before death or euthanasia. In five affected dogs serial blood samples were obtained, and dramatically elevated blood urea nitrogen and creatinine levels were demonstrated up to 2.75 years before death. Protein-creatinine ratios were elevated in six of six dogs and were above normal 3.5 years before death in one dog. The kidneys appeared grossly normal to slightly smaller than normal at necropsy. Histologic abnormalities of the kidneys were consistent with chronic glomerulonephropathy with sclerosis. Examination of the pedigrees of related affected dogs yielded evidence supporting an autosomal recessive mode of inheritance.

Transgenic mice with a targeted disruption of the tumor necrosis factor receptor 1 (TNFR1) gene were used to analyze the role of TNF-alpha in pro- and anti-inflammatory mediator production and liver injury induced by acetaminophen. Treatment of wild-type mice with acetaminophen (300 mg/kg) resulted in centrilobular hepatic necrosis. This was correlated with expression of inducible nitric oxide synthase (NOS II) and nitrotyrosine staining of the liver. Expression of macrophage chemotactic protein-1 (MCP-1), KC/gro, interleukin-1beta (IL-1beta), matrix metalloproteinase-9 (MMP-9), and connective tissue growth factor (CTGF), inflammatory mediators known to participate in tissue repair, as well as the anti-inflammatory cytokine, interleukin-10 (IL-10), also increased in the liver following acetaminophen administration. TNFR1(-/-) mice were found to be significantly more sensitive to the hepatotoxic effects of acetaminophen than wild-type mice. This was correlated with more rapid and prolonged induction of NOS II in the liver and changes in the pattern of nitrotyrosine staining. Acetaminophen-induced expression of MCP-1, IL-1beta, CTGF, and MMP-9 mRNA was also delayed or reduced in TNFR1(-/-) mice relative to wild-type mice. In contrast, increases in IL-10 were more rapid and more pronounced. These data demonstrate that signaling through TNFR1 is important in inflammatory mediator production and toxicity induced by acetaminophen.

Objective The transcription of several cytokines, cell adhesion molecules, and enzymes involved in the inflammatory and destructive mechanisms of rheumatoid arthritis is dependent on nuclear factor κB (NF-κB). Because IκB kinase (IKK) is critical in transducing the signal-inducible activation of NF-κB, we examined whether the highly selective and orally bioavailable IKK inhibitor BMS-345541 is efficacious against collagen-induced arthritis (CIA) in mice. Methods Arthritis in DBA/1LacJ male mice was induced by subcutaneous immunization with bovine type II collagen on day 0 and day 21. BMS-345541 was administered perorally daily, either prophylactically (before disease onset) or therapeutically (after disease onset). Clinical assessment of the incidence and severity of disease was conducted throughout the study, and histologic evaluation was performed at the time of study termination (day 42). Results When administered prophylactically, BMS-345541 (in a dose range of 10–100 mg/kg) was effective, in a dose-dependent manner, in reducing the incidence of disease and inhibiting clinical signs of disease. Histologic evaluation of the joints showed that both inflammation and joint destruction were blocked by the IKK inhibitor. Message levels of interleukin-1β in the joints were also dose-dependently inhibited in the mice that received BMS-345541. Dose-dependent efficacy in terms of both disease severity and histologic end points was observed with the therapeutic dosing regimen of BMS-345541, with use of the 100-mg/kg dose resulting in resolution of disease. Conclusion IKK plays a key role in CIA in mice, and inhibitors of this enzyme represent a promising target for the development of novel agents to treat rheumatoid arthritis and other inflammatory diseases. BMS-345541 represents the first example of an inhibitor of IKK that has antiinflammatory activity in vivo.

Macrophage-derived inflammatory mediators have been implicated in tissue injury induced by a number of hepatotoxicants. In the present studies, we used transgenic mice with a targeted disruption of the gene for inducible nitric oxide synthase (NOS II) to analyze the role of nitric oxide in inflammatory mediator production in the liver and in tissue injury induced by acetaminophen. Treatment of wild-type mice with acetaminophen (300 mg/kg) resulted in centrilobular hepatic necrosis, which was evident within 3 h and reached a maximum at 18 h. This was correlated with NOS II expression and nitrotyrosine staining of the liver, which was most prominent after 6 h. Expression of mRNA for tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), matrix metalloproteinase-9, and connective tissue growth factor (CTGF) also increased in the liver following acetaminophen treatment of wild-type mice. NOS II knockout mice were found to be less sensitive to the hepatotoxic effects of acetaminophen than wild-type mice. This did not appear to be due to differences in acetaminophen-induced glutathione depletion or adduct formation. In NOS II knockout mice treated with acetaminophen, hepatic expression of TNF-α, as well as CTGF, was significantly increased compared to wild-type mice. In contrast, IL-10 expression was reduced. These data demonstrate that nitric oxide is important in hepatotoxicity induced by acetaminophen. Moreover, some of its effects may be mediated by altering production of pro- and antiinflammatory cytokines and proteins important in tissue repair.

The biological effects of monocyte chemoattractant protein (MCP) 1 are mediated by binding to C-C chemokine receptor (CCR) 2. In the present studies, we used CCR2 knockout (CCR2-/-) mice to examine the role of MCP-1 in acetaminophen-induced macrophage accumulation in the liver, expression of inflammatory cytokines, and hepatotoxicity. We found that hepatic expression of CCR2 and MCP-1 was increased 10-fold and 20-fold, respectively, 12 to 72 hours after administration of acetaminophen to wild-type mice. Expression of these proteins was localized in centrilobular regions of the liver. Whereas MCP-1 was expressed by both hepatocytes and macrophages, CCR2 was identified in inflammatory macrophages. F4/80 is a marker of mature macrophages expressed in large quantities by Kupffer cells. In wild-type mice, a 75% decrease in F4/80-positive macrophages was observed 24 to 48 hours after administration of acetaminophen. In contrast, expression of macrosialin (CD68), a marker of activated macrophages, increased 2-fold 24 to 72 hours after administration of acetaminophen and was associated with inflammatory cells. Although there was a decrease in the overall severity of inflammation and in the number of macrosialin-positive macrophages 72 hours after administration of acetaminophen in CCR2-/- mice, the number of F4/80-positive cells did not change. Loss of CCR2 was also found to alter acetaminophen-induced expression of tumor necrosis factor alpha, monocyte chemoattractant protein 3, and KC/gro. However, the overall outcome of acetaminophen-induced hepatic injury was not affected. In conclusion, these data indicate that MCP-1 and CCR2 contribute to the recruitment of a subset of activated macrophages into the liver during acetaminophen-induced hepatotoxicity that may be important in resolution of tissue injury.

A novel dilated cardiomyopathy (DCM) in 12 related Portuguese Water Dogs was identified by retrospective analysis of postmortem and biopsy case records. Male and female puppies born to clinically healthy parents typically died at 13 (+/- 7.3) weeks of age (range, 2-32 weeks) because of congestive heart failure. Puppies died suddenly without previous signs or with mild depression followed by clinical signs of congestive heart failure 1-5 days before death. There was no sex predilection. The hearts were enlarged and rounded, with marked left ventricular and atrial dilation. No other significant structural cardiac defects were noted. The histologic changes in the myocardium were diffuse and characterized by myofibers of irregular sizes separated by an edematous interstitium. The myofibers had multifocal swollen, cleared segments often involving perinuclear areas that contained granular, phosphotungstic-acid-hematoxylin-positive material consistent with mitochondria. There was loss of the cross-striation pattern, and intercalated discs were difficult to identify. There was no evidence of concurrent myocardial fibrosis; rare chronic inflammatory infiltrates were noted in one dog. Noncardiac skeletal muscles were not affected. The underlying cause is unknown. From the pedigree analysis, an autosomal recessive pattern of inheritance is suspected. Based on the histologic findings, this DCM is most likely due to an underlying molecular (biochemical or structural) defect. The early onset and rapid progression of the disease makes this a clinically distinctive form of canine DCM.

The polypeptide (p)50 molecule, a subunit of nuclear factor (NF)-kappaB, is produced after proteolytic processing of the p105 precursor (NF-kappaB1). Although the p105 precursor has been postulated to play a role in the regulation of the Rel/NF-kappaB activity, its physiological relevance remains unclear. To investigate that, we generated mutant mice lacking the COOH terminal half of the p105 precursor, but expressing the p50 product (p105-/-). These mutant mice displayed an inflammatory phenotype composed of lymphocytic infiltration in lungs and liver, and an increased susceptibility to opportunistic infections. Enlargement of multiple lymph nodes, splenomegaly due to erythrocytic extramedullary hematopoiesis, and lymphoid hyperplasia were also observed in p105-/- mice. Cytokine production in p105-/- macrophages was severely impaired, whereas proliferative responses of p105-/- B cells were increased. T cell functions were only moderately impaired in mutant mice. Loss of p105 also led to enhanced constitutive p50 homodimer and inducible NF-kappaB activities in unstimulated and stimulated cells, respectively. As several genes regulated by Rel/NF-kappaB were upregulated in p105-/- thymus but downregulated in p105-/- macrophages, the enhanced p50 homodimers appear to function as transcriptional activators or repressors, depending on the cell type. Thus, the p105 precursor is indispensable in the control of p50 activity, and lack of the precursor has distinct effects on different cells.

Development of pink salmon (Oncorhynchus gorbuscha) incubating in gravel contaminated with weathered Prudhoe Bay crude oil was retarded at concentrations as low as 55.2 μg oil/g gravel. Larvae exposed to various levels of oil contamination were sampled 4 weeks before emergence, at emergence, and 13 days after emergence for histopathology (quantitative and semiquantitative) and cytochrome P4501A (CYP1A) induction (using immunohistochemical staining). A subset of postemergent fish was not fed. Hydrocarbon analysis by gas chromatography and mass spectroscopy revealed that tissue uptake of polynuclear aromatic hydrocarbons (PAH) was mediated by oil's dissolution in water, with significant biological effects when the peak total PAH concentration in water was as low as 4.4 μg/L. Oil-related effects included induction of CYP1A, development of ascites, and increased mortality. Several oil-related changes were indicative of premature emergence. Compared with control fish, for example, exposed fish of the same age and emerging on the same day had greater amounts of yolk and hepatocellular glycogen, increased apoptosis of gonadal cells and midventral skin cells, and less food in the gastrointestinal tract. Histological features were similar within groups of larvae sampled 4 weeks before and 13 days after emergence, and oil-induced changes were not affected by feeding during the first 13 days after emergence. Increased gonadal cell apoptosis may be related to later reproductive impairment documented in field studies of pink salmon up to 4 years after the Exxon Valdez oil spill.

A five-month-old male Labrador retriever presented with massive bilateral jaw and facial swelling. Ulcers were found on the buccal mucosa and palate, and the jaws were flexible on firm palpation. The dog could eat only soft food and was underweight. Renal hyperparathyroidism was diagnosed based on serum chemistry screen, parathormone concentration, radiological findings and histopathology. The dog was euthanatized because of an extremely poor prognosis.

CD137 plays an important role as a co-stimulatory molecule in activated T cells. Agonistic CD137 specific antibodies have been investigated as therapeutic agents to promote tumor-specific immune responses by direct activation of T cells. As part of the pre-clinical pharmacological evaluation of cynomolgus monkeys, monkey CD137 was cloned and characterized. The deduced amino acid sequence encoded a full-length gene of 254 amino acids 95% identical to human CD137. Sequence variants identified in monkey CD137 include four splice variants lacking the transmembrane domain. These variants were detectable in human including two previously unreported variants. Two missense single nucleotide polymorphisms were detected present in 42 and 50% of 36 monkeys tested. In both monkey and human, mRNA expression of full-length CD137 and splice variants were significantly increased in peripheral blood mononuclear cells (PBMCs) upon stimulation by anti-CD3 antibodies. Recombinant monkey CD137 protein was bound with high affinity by an agonistic anti-human CD137 antibody but not by an anti-mouse CD137 antibody. In summary, compared to human, monkey CD137 showed distinct extracellular domain amino acid sequence and sequence polymorphisms. Thus, antibodies directed against epitopes in this extracellular domain could have differences in pharmacologic activity between cynomolgus monkeys and human or across individual cynomolgus monkeys.

Toxicogenomics is considered a valuable tool for reducing pharmaceutical candidate attrition by facilitating earlier identification, prediction and understanding of toxicities. A retrospective evaluation of 3 years of routine transcriptional profiling in non-clinical safety studies was undertaken to assess the utility of toxicogenomics in drug safety assessment. Based on the analysis of studies with 33 compounds, marked global transcriptional changes (>4% transcripts at p < 0.01) were shown to be a robust biomarker for dosages considered to be toxic. In general, there was an inconsistent correlation between transcription and histopathology, most likely due to differences in sensitivity to focal microscopic lesions, to secondary effects, and to events that precede structural tissue changes. For 60% of toxicities investigated with multiple time-point data, transcriptional changes were observed prior to changes in traditional study endpoints. Candidate transcriptional markers of pharmacologic effects were detected in 40% of targets profiled. Mechanistic classification of toxicity was obtained for 30% of targets. Furthermore, data comparison to compendia of transcriptional changes provided assessments of the specificity of transcriptional responses. Overall, our experience suggests that toxicogenomics has contributed to a greater understanding of mechanisms of toxicity and to reducing drug attrition by empiric analysis where safety assessment combines toxicogenomic and traditional evaluations.

Hepatotoxicity remains a significant cause for drug failures during clinical trials. This is due, in part, to the idiosyncratic nature of toxicity in humans and inherent physiological differences between humans and preclinical species leading to limited correct prediction of adverse responses in humans. To address this issue, robust screening assays are being developed, which have heightened predictive capacity for human hepatotoxicity, and may be utilized throughout the discovery and development phases in conjunction with traditional in vivo methods, for decision making during drug selection and risk assessment. This manuscript describes an example application of in vitro-based strategies using human hepatocyte cultures in lead optimization screening in conjunction with ADME profiling, for evaluation of compound-associated CYP450 induction potential, and the identification of potentially useful biomarkers as predictors of hepatotoxicity for use in vitro, and in preclinical species and humans.

Hepatocyte proliferation represents an important part of tissue repair. In these studies, TNF receptor 1 (TNFR1) knockout mice were used to analyze the role of TNF-alpha in hepatocyte proliferation during acetaminophen-induced hepatotoxicity. Treatment of wild-type (WT) mice with acetaminophen (300 mg/kg) resulted in centrilobular hepatic necrosis. This was associated with proliferation of hepatocytes surrounding the damaged areas, which was evident at 24 h. The cell cycle regulatory proteins, cyclin D1 and cyclin A, were also up regulated in hepatocytes. In contrast, in TNFR1-/- mice, which exhibit exaggerated acetaminophen hepatotoxicity, hepatocyte proliferation, and expression of cyclin D1 and cyclin A, as well as the cyclin dependent kinases, Cdk4 and Cdk2, were reduced. The cyclin-dependent kinase inhibitor p21 was also induced in the liver following acetaminophen administration. This was greater in TNFR1-/- mice compared to WT mice. To investigate mechanisms mediating the reduced hepatic proliferative response of TNFR1-/- mice, we analyzed phosphatidyl inositol-3-kinase (PI-3K) signaling. In both WT and TNFR1-/- mice, acetaminophen caused a rapid increase in total PI-3K within 3 h. Acetaminophen also increased phosphorylated PI-3K, but this was delayed 6-12 h in TNFR1-/- mice. Expression of Akt, a downstream target of PI-3K, was increased in both WT and TNFR1-/- mice in response to acetaminophen. However, the increase was greater in WT mice. Acetaminophen-induced expression of phosphorylated STAT3, a key regulator of cytokine-induced hepatocyte proliferation, was also delayed in TNFR1-/- mice relative to WT. These data suggest that TNF-alpha signaling through TNFR1 is important in regulating hepatocyte proliferation following acetaminophen-induced tissue injury. Delayed cytokine signaling may account for reduced hepatocyte proliferation and contribute to exaggerated acetaminophen-induced hepatotoxicity in TNFR1-/- mice.

Drug-induced idiosyncratic hepatotoxicity continues to be an important safety issue for the pharmaceutical industry. This toxicity is due, in part, to the limited predictive nature of current pre-clinical study systems. A hypothesis was formed that treatment of existing in vitro hepatocyte cultures with drugs clinically linked to idiosyncratic hepatotoxicity would result in the release of extracellular protein biomarkers indicative of liver toxicity. To test this hypothesis, a combination of proteomic and immunological techniques were used to first identify, and subsequently verify, components of the protein-laden conditioned culture media from immortalized human hepatocytes which overexpressed cytochrome P450 3A4. These cells were treated separately with seven individual compounds made up of a combination of thiazolidinedione and l -tyrosine PPARγ agonists and HIV protease inhibitors, plus a vehicle control (dimethyl sulfoxide). For each drug class, clinically determined hepatotoxic and non-hepatotoxic compounds were compared. Two proteins, BMS-PTX-265 and BMS-PTX-837, were reproducibly and significantly increased in the conditioned media from cells treated with each of the toxic compounds as compared to media from cells treated with the non-toxic compounds (and vehicle). This result supported the hypothesis, and so a series of successive assays (western blots and enzyme linked immunosorbent assays) were used to measure the response of these two proteins as a function of an expanded set of 20 compounds. For all 20 drugs, elevations of BMS-PTX-265 correlated exactly with the known safety profile; whereas changes in BMS-PTX-837 correctly predicted the safety profile in 19 of 20 drugs (one false negative). In summary, the data supports both the pre-clinical in vitro method as a means to identify new biomarkers of liver toxicity, as well as the validity of the biomarkers themselves.

Tumor necrosis factor (TNF)-alpha is a macrophage-derived proinflammatory cytokine implicated in hepatotoxicity. In the present studies, p55 TNF receptor 1 (TNFR1) -/- mice were used to assess the role of TNF-alpha in acetaminophen-induced antioxidant defense. Treatment of wild-type (WT) mice with acetaminophen (300 mg/kg) resulted in centrilobular hepatic necrosis and increased serum alanine transaminases. This was correlated with a rapid depletion of hepatic glutathione (GSH). Whereas in WT mice GSH levels returned to control after 6-12 h, in TNFR1-/- mice recovery was delayed for 48 h. Delayed induction of heme oxygenase-1 and reduced expression of CuZn superoxide dismutase were also observed in TNFR1-/- compared with WT mice. This was associated with exaggerated hepatotoxicity. In WT mice, acetaminophen caused a time-dependent increase in activator protein-1 nuclear binding activity and in c-Jun expression. This response was significantly attenuated in TNFR1-/- mice. Constitutive NF-kappaB binding activity was detectable in livers of both WT and TNFR1-/- mice. A transient decrease in this activity was observed 3 h after acetaminophen in WT mice, followed by an increase that was maximal after 6-12 h. In contrast, in TNFR1-/- mice, acetaminophen-induced decreases in NF-kappaB activity were prolonged and did not return to control levels for 24 h. These data indicate that TNF-alpha signaling through TNFR1 plays an important role in regulating the expression of antioxidants in this model. Reduced generation of antioxidants may contribute to the increased sensitivity of TNFR1-/- mice to acetaminophen.

Inflammatory bowel diseases such as ulcerative colitis and Crohn's disease are characterized by chronic relapsing inflammation. The transcription of many of the proteins which mediate the pathogenesis in inflammatory bowel disease (e.g., TNFalpha, ICAM-1, VCAM-1) is NF-kappaB-dependent. IkappaB kinase is critical in transducing the signal-inducible activation of NF-kappaB and, therefore, represents a potentially promising target for the development of novel agents to treat inflammatory bowel disease and other inflammatory diseases.Here we show that BMS-345541, a highly selective inhibitor of IkappaB kinase, inhibited the TNFalpha-induced expression of both ICAM-1 and VCAM-1 in human umbilical vein endothelial cells at the same concentration range as cytokine expression is inhibited in monocytic cells (IC(50) congruent with 5 microM). Against dextran sulfate sodium-induced colitis in mice, BMS-345541 administered orally at doses of 30 and 100 mg/kg was effective in blocking both clinical and histological endpoints of inflammation and injury.This represents the first example of an inhibitor of IkappaB kinase with anti-inflammatory activity in vivo and indicates that inhibitors of IkB kinase show the promise of being highly efficacious in inflammatory disorders such as inflammatory bowel disease.

Macrophage-derived inflammatory mediators have been implicated in tissue injury induced by a number of hepatotoxicants. In the present studies, we used transgenic mice with a targeted disruption of the gene for inducible nitric oxide synthase (NOS II) to analyze the role of nitric oxide in inflammatory mediator production in the liver and in tissue injury induced by acetaminophen. Treatment of wild-type mice with acetaminophen (300 mg/kg) resulted in centrilobular hepatic necrosis, which was evident within 3 h and reached a maximum at 18 h. This was correlated with NOS II expression and nitrotyrosine staining of the liver, which was most prominent after 6 h. Expression of mRNA for tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10), matrix metalloproteinase-9, and connective tissue growth factor (CTGF) also increased in the liver following acetaminophen treatment of wild-type mice. NOS II knockout mice were found to be less sensitive to the hepatotoxic effects of acetaminophen than wild-type mice. This did not appear to be due to differences in acetaminophen-induced glutathione depletion or adduct formation. In NOS II knockout mice treated with acetaminophen, hepatic expression of TNF-alpha, as well as CTGF, was significantly increased compared to wild-type mice. In contrast, IL-10 expression was reduced. These data demonstrate that nitric oxide is important in hepatotoxicity induced by acetaminophen. Moreover, some of its effects may be mediated by altering production of pro- and antiinflammatory cytokines and proteins important in tissue repair.

To date, few animal models of chronic obstructive pulmonary disease (COPD) exist that are ideal for the evaluation of pathophysiology, as they typically require many months of cigarette smoke exposure in inhalation facilities. Here we show that pulmonary inflammation and some of the inflammatory hallmarks of COPD can be induced in mice by cigarette smoke-conditioned media (CS) administered by the intranasal route. Balb/c mice were challenged with CS for up to 40 days. At the end of smoke treatment, mice were sacrificed and bronchoalveolar lavage (BAL) fluid collected. Total cell counts and cell differentials were performed. Enzyme-linked immunosorbent assays (ELISAs) for KC and tumor necrosis factor alpha (TNF-alpha) were performed on BAL fluid. Lungs and nasal cavities were examined histologically. Intranasal CS treatment significantly increased BAL neutrophils, lymphocytes, KC, TNF-alpha, and mucin. Changes in pulmonary reactivity to methacholine were also observed in mice challenged with CS for 40 days. The model described above demonstrates that within 1 to 8 weeks of intranasal instillation of CS, mice develop pulmonary inflammation and cellular lung changes that are characteristic of human COPD and therefore may be a good short-term in vivo model that can be utilized to monitor intervention strategies targeted for COPD.

Polycystic kidney and liver disease was present in four of six female and three of five male offspring born in two matings between the same pair of West Highland White Terriers. Clinical signs were apparent and serum biochemistry analysis consistent with liver failure was evident by 5 weeks of age. Affected pups were euthanatized because of their disease. Renal cysts were confirmed to be of collecting duct origin by Dolichos bifluros agglutinin lectin histochemistry, and hepatic cysts were of biliary origin. The clinically unaffected parents were related through multiple common ancestors, and there were no reports of similar disease in related dogs. An autosomal recessive mode of inheritance is therefore suggested. This is the first report of polycystic kidney and liver disease in the West Highland White Terrier. The features of the disease in these pups are similar to those of autosomal recessive polycystic kidney disease (ARPKD) in humans. The West Highland White Terrier may therefore be a potential animal model for ARPKD.

A distinctive renal lesion consisting of glomerulonephritis, diffuse tubular necrosis with regeneration, and interstitial inflammation was found in 49 biopsy/necropsy cases obtained from 1987 to 1992. This lesion is manifested clinically as a rapidly progressive glomerular disease that was uniformily fatal. Immunemediated membranoproliferative glomerulonephritis predominated (43/49, 88%). Membranous glomerulonephritis (5/49, 10%) and amyloidosis (1/49, 2%) were also noted. Subendothelial deposits, IgG, IgM, and C3 were present along glomerular basement membranes. IgA was absent. The exact cause of the tubular necrosis is unknown. Affected dogs were significantly younger (5.6 ± 2.6 years) than dogs with other forms of glomerulonephritis (7.1 ± 3.6 years) and amyloidosis (7.8 ± 3.5 years) both in the studied population for the same period and in the reported canine population. Labrador and Golden retrievers were 6.4 and 4.9 times more likely, respectively, to develop this lesion. This is the first report of a breed predilection for spontaneous canine glomerulonephritis. Previous reports have associated this lesion with Borrelia burgdorferi exposure. All dogs in this study were from Lyme disease-endemic areas. Of 18 dogs serologically tested, all were positive for exposure. Silver stain examination of kidneys revealed rare spirochetes, suggesting that the presence of spirochetes in the kidney is apparently unrelated to lesion development. The role of vaccination in development of the renal lesion is undetermined. The association of this histologically and clinically unique lesion, Lyme nephritis, with Borrelia burgdorferi infection is significant because it is the only fatal form of canine Lyme borreliosis.

Records and pedigrees of Soft Coated Wheaten Terriers (SCWT) with protein-losing enteropathy (PLE) or protein-losing nephropathy (PLN) were studied retrospectively. Criteria for inclusion were defined based on analysis of blood (panhypoproteinemia for PLE, hypoalbuminemia for PLN) and urine (proteinuria for PLN) and histopathologic examination of tissue. Two hundred twenty-two affected dogs (female:male ratio = 1.6, P < .001) were clinically identified. Dogs were diagnosed with PLE earlier (P < .005; mean +/- SD age: 4.7+/-2.6 years, n = 76) than with PLN (6.3+/-2.0 years, n = 84) or with both diseases (5.9+/-2.2 years, n = 62). Clinical signs included vomiting, diarrhea, weight loss, pleural and peritoneal effusions, and less commonly thromboembolic disease. Dogs with PLE generally had panhypoproteinemia and hypocholesterolemia; intestinal lesions included inflammatory bowel disease, dilated lymphatics, and lipogranulomatous lymphangitis. Dogs with PLN generally had hypoalbuminemia, proteinuria, hypercholesterolemia, and azotemia; renal lesions typically showed chronic glomerulonephritis/glomerulosclerosis, and less commonly endstage renal disease. Dogs with combined PLE/PLN had intermediate mean values (P < .001) for serum total protein, albumin, globulin, and cholesterol but had a higher mean urine protein:creatinine ratio than did PLN dogs (P < .05); intestinal and renal lesions in these dogs were similar to those in the other groups. Two dogs had incidental mild renal dysplasia. Pedigree analysis from 188 dogs demonstrated a common male ancestor, although the mode of inheritance is unknown. Both PLE and PLN are common diseases in this small breed population. The prognosis is poor. Compared with previously reported intestinal and renal diseases in dogs, a new, distinctive familial predisposition for both PLE and PLN has been recognized in the SCWT breed.

MHV-A59 causes a chronic demyelinating disease in mice which is accompanied by persistence of viral genome in white matter. As part of the investigation into the mechanism of viral persistence, infection of glial cells, probable targets for chronic infection, was studied by the use of mixed glial, enriched oligodendrocyte and enriched astrocyte cultures. Following MHV-A59 infection in vitro, approximately 10% of oligodendrocytes and 30% of astrocytes expressed viral antigens in the absence of overt cytopathic effect. All cultures released infectious virus for the lifetime of the cultures, for at least 45 days in the case of mixed glial cultures. Cultures derived from previously infected mice were similar to those infected in vitro with respect to percentage of cells expressing viral antigen and levels of infectious virus produced. These results show (1) that glial cells are early sites of infection in vivo as well as sites of infection in in vitro cultures, and (2) that glial cells support a non-lytic but productive infection in vitro and thus may contribute to viral persistence in vivo.