Mouse psychosocial stress reduces motivation and cognitive function in operant reward tests:A model for reward pathology with effects of agomelatine

A major domain of depression is decreased motivation for reward. Translational automated tests can be applied in humans and animals to study operant reward behaviour, aetio-pathophysiology underlying deficits therein, and effects of antidepressant treatment. Three inter-related experiments were conducted to investigate depression-relevant effects of chronic psychosocial stress on operant behaviour in mice. (A) Non-manipulated mice were trained on a complex reversal learning (CRL) test with sucrose reinforcement; relative to vehicle (VEH), acute antidepressant agomelatine (AGO, 25mg/kg p.o.) increased reversals. (B) Mice underwent chronic social defeat (CSD) or control handling (CON) on days 1-15, and were administered AGO or VEH on days 10-22. In a progressive ratio schedule motivation test for sucrose on day 15, CSD mice made fewer responses; AGO tended to reverse this effect. In a CRL test on day 22, CSD mice completed fewer reversals; AGO tended to increase reversals in CSD mice associated with an adaptive increase in perseveration. (C) Mice with continuous operant access to water and saccharin solution in the home cage were exposed to CSD or CON; CSD mice made fewer responses for saccharin and water and drank less saccharin in the active period, and drank more water in the inactive period. In a separate CSD cohort, repeated AGO was without effect on these home cage operant and consummatory changes. Overall, this study demonstrates that psychosocial stress in mice leads to depression-relevant decreases in motivation and cognition in operant reward tests; partial reversal of these deficits by AGO provides evidence for predictive validity

Two first-in-human studies of xentuzumab, a humanised insulin-like growth factor (IGF)-neutralising antibody, in patients with advanced solid tumours

BACKGROUND: Xentuzumab, an insulin-like growth factor (IGF)-1/IGF-2-neutralising antibody, binds IGF-1 and IGF-2, inhibiting their growth-promoting signalling. Two first-in-human trials assessed the maximum-tolerated/relevant biological dose (MTD/RBD), safety, pharmacokinetics, pharmacodynamics, and activity of xentuzumab in advanced/metastatic solid cancers. METHODS: These phase 1, open-label trials comprised dose-finding (part I; 3 + 3 design) and expansion cohorts (part II; selected tumours; RBD [weekly dosing]). Primary endpoints were MTD/RBD. RESULTS: Study 1280.1 involved 61 patients (part I: xentuzumab 10–1800 mg weekly, n = 48; part II: 1000 mg weekly, n = 13); study 1280.2, 64 patients (part I: 10–3600 mg three-weekly, n = 33; part II: 1000 mg weekly, n = 31). One dose-limiting toxicity occurred; the MTD was not reached for either schedule. Adverse events were generally grade 1/2, mostly gastrointestinal. Xentuzumab showed dose-proportional pharmacokinetics. Total plasma IGF-1 increased dose dependently, plateauing at ~1000 mg/week; at ≥450 mg/week, IGF bioactivity was almost undetectable. Two partial responses occurred (poorly differentiated nasopharyngeal carcinoma and peripheral primitive neuroectodermal tumour). Integration of biomarker and response data by Bayesian Logistic Regression Modeling (BLRM) confirmed the RBD. CONCLUSIONS: Xentuzumab was well tolerated; MTD was not reached. RBD was 1000 mg weekly, confirmed by BLRM. Xentuzumab showed preliminary anti-tumour activity

Two first-in-human studies of xentuzumab, a humanised insulin-like growth factor (IGF)-neutralising antibody, in patients with advanced solid tumours

Background Xentuzumab, an insulin-like growth factor (IGF)-1/IGF-2-neutralising antibody, binds IGF-1 and IGF-2, inhibiting their growth-promoting signalling. Two first-in-human trials assessed the maximum-tolerated/relevant biological dose (MTD/RBD), safety, pharmacokinetics, pharmacodynamics, and activity of xentuzumab in advanced/metastatic solid cancers. Methods These phase 1, open-label trials comprised dose-finding (part I; 3 + 3 design) and expansion cohorts (part II; selected tumours; RBD [weekly dosing]). Primary endpoints were MTD/RBD. Results Study 1280.1 involved 61 patients (part I: xentuzumab 10–1800 mg weekly, n = 48; part II: 1000 mg weekly, n = 13); study 1280.2, 64 patients (part I: 10–3600 mg three-weekly, n = 33; part II: 1000 mg weekly, n = 31). One dose-limiting toxicity occurred; the MTD was not reached for either schedule. Adverse events were generally grade 1/2, mostly gastrointestinal. Xentuzumab showed dose-proportional pharmacokinetics. Total plasma IGF-1 increased dose dependently, plateauing at ~1000 mg/week; at ≥450 mg/week, IGF bioactivity was almost undetectable. Two partial responses occurred (poorly differentiated nasopharyngeal carcinoma and peripheral primitive neuroectodermal tumour). Integration of biomarker and response data by Bayesian Logistic Regression Modeling (BLRM) confirmed the RBD. Conclusions Xentuzumab was well tolerated; MTD was not reached. RBD was 1000 mg weekly, confirmed by BLRM. Xentuzumab showed preliminary anti-tumour activity. Clinical trial registration NCT01403974; NCT01317420

Phase I dose-escalation study of volasertib in pediatric patients with acute leukemia or advanced solid tumors

Background: Volasertib induces mitotic arrest and apoptosis by targeting Polo-like kinases. In this phase I dose-escalation study, the maximum tolerated dose (MTD), pharmacokinetics (PK), and preliminary efficacy of volasertib were determined in pediatric patients. Methods: Patients aged 2 to <18 years with relapsed/refractory acute leukemia/advanced solid tumors (ST) without available effective treatments were enrolled—cohort C1 (aged 2 to <12 years); cohort C2 (aged 12 to <18 years). The patients received volasertib intravenously (starting dose: 200 mg/m2 body surface area on day 1, every 14 days). The primary endpoint was the pediatric MTD for further development. Results: Twenty-two patients received treatment (C1: leukemia, n = 4; ST, n = 8; C2: leukemia, n = 3; ST, n = 7). No dose-limiting toxicities (DLTs) occurred up to 300 mg/m2 volasertib in C1; two patients in C2, at 250 mg/m2 volasertib, had DLTs in cycle 1, one of which led to death; therefore, the MTD of volasertib in C2 was 200 mg/m2. The most common grade 3/4 adverse events (all patients) were febrile neutropenia, thrombocytopenia, and neutropenia (41% each). Stable disease (SD) was the best objective response (leukemia, n = 5; ST, n = 2); the duration of SD was short in all patients, except in one with an ST. PK profiles were generally comparable across dose groups and were consistent with those in adults. Conclusion: The pediatric MTD/dose for further development was identified. There were no unexpected safety or PK findings; limited antitumor/antileukemic activity was demonstrated

Mouse chronic social stress increases blood and brain kynurenine pathway activity and fear behaviour: both effects are reversed by inhibition of indoleamine 2,3-dioxygenase

Psychosocial stress is a major risk factor for mood and anxiety disorders, in which excessive reactivity to aversive events/stimuli is a major psychopathology. In terms of pathophysiology, immune-inflammation is an important candidate, including high blood and brain levels of metabolites belonging to the kynurenine pathway. Animal models are needed to study causality between psychosocial stress, immune-inflammation and hyper-reactivity to aversive stimuli. The present mouse study investigated effects of psychosocial stress as chronic social defeat (CSD) versus control-handling (CON) on: Pavlovian tone-shock fear conditioning, activation of the kynurenine pathway, and efficacy of a specific inhibitor (IDOInh) of the tryptophan-kynurenine catabolizing enzyme indoleamine 2,3-dioxygenase (IDO1), in reversing CSD effects on the kynurenine pathway and fear. CSD led to excessive fear learning and memory, whilst repeated oral escitalopram (antidepressant and anxiolytic) reversed excessive fear memory, indicating predictive validity of the model. CSD led to higher blood levels of TNF-α, IFN-γ, kynurenine (KYN), 3-hydroxykynurenine (3-HK) and kynurenic acid, higher KYN and 3-HK in amygdala and hippocampus. However, CSD was without effect on IDO1 gene or protein expression in spleen, ileum and liver, whilst increasing liver TDO2 gene expression. Nonetheless, oral IDOInh reduced blood and brain levels of KYN and 3-HK in CSD mice to CON levels, and we therefore infer that CSD increases IDO1 activity by increasing its post-translational activation. Furthermore, repeated oral IDOInh reversed excessive fear memory in CSD mice to CON levels. IDOInh reversal of CSD-induced hyper-activity in the kynurenine pathway and fear system contributes significantly to the evidence for a causal pathway between psychosocial stress, immune-inflammation and the excessive fearfulness that is a major psychopathology in stress-related neuropsychiatric disorders

CD40-TNF activation in mice induces extended sickness behavior syndrome co-incident with but not dependent on activation of the kynurenine pathway

The similarity between sickness behavior syndrome (SBS) in infection and autoimmune disorders and certain symptoms in major depressive disorder (MDD), and the high co-morbidity of autoimmune disorders and MDD, constitutes some of the major evidence for the immune-inflammation hypothesis of MDD. CD40 ligand-CD40 immune-activation is important in host response to infection and in development of autoimmunity. Mice given a single intra-peritoneal injection of CD40 agonist antibody (CD40AB) develop SBS for 2-3days characterized by weight loss and increased sleep, effects that are dependent on the cytokine, tumor necrosis factor (TNF). Here we report that CD40AB also induces behavioral effects that extend beyond acute SBS and co-occur with but are not mediated by kynurenine pathway activation and recovery. CD40AB led to decreased saccharin drinking (days 1-7) and decreased Pavlovian fear conditioning (days 5-6), and was without effect on physical fatigue (day 5). These behavioral effects co-occurred with increased plasma and brain levels of kynurenine and its metabolites (days 1-7/8). Co-injection of TNF blocker etanercept with CD40AB prevented each of SBS, reduced saccharin drinking, and kynurenine pathway activation in plasma and brain. Repeated oral administration of a selective indoleamine 2,3-dioxygenase (IDO) inhibitor blocked activation of the kynurenine pathway but was without effect on SBS and saccharin drinking. This study provides novel evidence that CD40-TNF activation induces deficits in saccharin drinking and Pavlovian fear learning and activates the kynurenine pathway, and that CD40-TNF activation of the kynurenine pathway is not necessary for induction of the acute or extended SBS effects

Differential effects of peripheral and brain tumor necrosis factor on inflammation, sickness, emotional behavior and memory in mice

Tumor necrosis factor alpha (TNF) is increased in depression and clinical-trial evidence indicates that blocking peripheral TNF has some antidepressant efficacy. In rodents, peripheral or intracerebroventricular TNF results in sickness e.g. reduced body weight, altered emotional behavior and impaired memory. However, the underlying pathways and responsible brain regions are poorly understood. The aim of this mouse study was to increase understanding by comparing the effects of sustained increases in TNF in the circulation, in brain regions impacted by increased circulating TNF, or specific brain regions. Increased peripheral TNF achieved by repeated daily injection (IP-TNF) or osmotic pump resulted in decreased body weight, decreased saccharin (reward) consumption, and increased memory of an aversive conditioned stimulus. These effects co-occurred with increased plasma interleukin-6 and increased IP-derived TNF in brain peri-ventricular regions. An adenovirus-associated viral TNF vector (AAV-TNF) was constructed, brain injection of which resulted in dose-dependent, sustained and region-specific TNF expression, and was without effect on blood cytokine levels. Lateral ventricle AAV-TNF yielded increased TNF in the same brain regions as IP-TNF. In contrast to IP-TNF it was without effect on body weight, saccharin consumption and fear memory, although it did increase anxiety. Hippocampal AAV-TNF led to decreased body weight. It increased conditioning to but not subsequent memory of an aversive context, suggesting impaired consolidation; it also increased anxiety. Amygdala AAV-TNF was without effect on body weight and aversive stimulus learning-memory, but reduced saccharin consumption and increased anxiety. This study adds significantly to the evidence that both peripheral and brain region-specific increases in TNF lead to both sickness and depression- and anxiety disorder-relevant behavior and do so via different pathways. It thereby highlights the complexity in terms of indirect and direct pathways via which increased TNF can act and which need to be taken into account when considering it as a therapeutic target

Depletion of nucleus accumbens dopamine leads to impaired reward and aversion processing in mice: Relevance to motivation pathologies

Dopamine (DA) neurotransmission, particularly the ventral tegmental area-nucleus accumbens (VTA-NAcc) projection, underlies reward and aversion processing, and deficient DA function could underlie motivational impairments in psychiatric disorders. 6-hydroxydopamine (6-OHDA) injection is an established method for chronic DA depletion, principally applied in rat to study NAcc DA regulation of reward motivation. Given the increasing focus on studying environmental and genetic regulation of DA function in mouse models, it is important to establish the effects of 6-OHDA DA depletion in mice, in terms of reward and aversion processing. This mouse study investigated effects of 6-OHDA-induced NAcc DA depletion using the operant behavioural test battery of progressive ratio schedule (PRS), learned non-reward (LNR), learned helplessness (LH), treadmill, and in addition Pavlovian fear conditioning. 6-OHDA NAcc DA depletion, confirmed by ex vivo HPLC-ED, reduced operant responding: for gustatory reward under effortful conditions in the PRS test; to a stimulus recently associated with gustatory non-reward in the LNR test; to escape footshock recently experienced as uncontrollable in the LH test; and to avoid footshock by physical effort in the treadmill test. Evidence for specificity of effects to NAcc DA was provided by lack of effect of medial prefrontal cortex DA depletion in the LNR and LH tests. These findings add significantly to the evidence that NAcc DA is a major regulator of behavioural responding, particularly at the motivational level, to both reward and aversion. They demonstrate the suitability of mouse models for translational study of causation and reversal of pathophysiological DA function underlying motivation psychopathologies

Adenosine-to-inosine RNA editing controls cathepsin S expression in atherosclerosis by enabling HuR-mediated post-transcriptional regulation

Adenosine-to-inosine (A-to-I) RNA editing, which is catalyzed by a family of adenosine deaminase acting on RNA (ADAR) enzymes, is important in the epitranscriptomic regulation of RNA metabolism. However, the role of A-to-I RNA editing in vascular disease is unknown. Here we show that cathepsin S mRNA (CTSS), which encodes a cysteine protease associated with angiogenesis and atherosclerosis, is highly edited in human endothelial cells. The 3' untranslated region (3' UTR) of the CTSS transcript contains two inverted repeats, the AluJo and AluSx(+) regions, which form a long stem-loop structure that is recognized by ADAR1 as a substrate for editing. RNA editing enables the recruitment of the stabilizing RNA-binding protein human antigen R (HuR; encoded by ELAVL1) to the 3' UTR of the CTSS transcript, thereby controlling CTSS mRNA stability and expression. In endothelial cells, ADAR1 overexpression or treatment of cells with hypoxia or with the inflammatory cytokines interferon-γ and tumor-necrosis-factor-α induces CTSS RNA editing and consequently increases cathepsin S expression. ADAR1 levels and the extent of CTSS RNA editing are associated with changes in cathepsin S levels in patients with atherosclerotic vascular diseases, including subclinical atherosclerosis, coronary artery disease, aortic aneurysms and advanced carotid atherosclerotic disease. These results reveal a previously unrecognized role of RNA editing in gene expression in human atherosclerotic vascular diseases