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Background: Small cell lung cancer (SCLC) is an aggressive malignancy. Current treatments yield dismal survival rates. We have previously demonstrated that histone deacetylase (HDAC) inhibitors can inhibit neuroendocrine tumor growth. Activation of the Notch1 signaling pathway also impairs SCLC cell viability. In this study, we investigated the ability of the HDAC inhibitor valproic acid (VPA) to activate Notch1 signaling and inhibit proliferation in SCLC cells. Materials and methods: DMS53 human SCLC cells were treated with VPA (0–10 mm) for 2 d. Light microscopy was used to examine changes in cell morphology. Western analysis was performed using antibodies against various Notch1 pathway proteins to assess Notch1 activation. Additionally, immunoblotting was performed for two neuroendocrine tumor markers, chromogranin A and achaete-scute complex-like 1. Finally, a cell proliferation assay was used to measure the effects of VPA on SCLC growth over 8 d. Results: After treatment with VPA, DMS53 cells underwent dramatic changes in morphology. VPA induced expression of the full-length and active forms of Notch1 protein. Furthermore, VPA suppressed levels of neuroendocrine tumor markers chromogranin A and ASLC-1. Importantly, VPA treatment led to dose-dependent inhibition of SCLC cell proliferation. Conclusions: The HDAC inhibitor VPA activates Notch1 signaling in SCLC cells. VPA induces changes in cell morphology and suppresses neuroendocrine tumor markers, indicating a change in phenotype. Additionally, VPA profoundly inhibits SCLC cell growth. These results suggest that VPA has potential as a novel therapeutic agent for SCLC. [Copyright &y& Elsevier]

Abstract: Histone deacetylases (HDACs) are key transcription regulators that function by deacetylating histones/transcription factors and modifying chromatin structure. In this work, we showed that chemical inhibition of HDACs by valproic acid (VPA) led to impaired liver development in zebrafish mainly by inhibiting specification, budding, and differentiation. Formation of exocrine pancreas but not endocrine pancreas was also inhibited. The liver defects induced by VPA correlate with suppressed total HDAC enzymatic activity, but are independent of angiogenesis inhibition. Gene knockdown by morpholino demonstrated that hdac3 is specifically required for liver formation while hdac1 is more globally required for multiple development processes in zebrafish including liver/exocrine pancreas formation. Furthermore, overexpression of hdac3 but not hdac1 partially rescued VPA induced small liver. One mechanism by which hdac3 regulates zebrafish liver growth is through inhibiting growth differentiation factor 11 (gdf11), a unique target of hdac3 and a member of the transforming growth factor β family. Simultaneous overexpression or morpholino knockdown showed that hdac3 and gdf11 function antagonistically in zebrafish liver development. These results revealed a novel and specific role of hdac3 in liver development and the distinct functions between hdac1 and hdac3 in zebrafish embryonic development. [Copyright &y& Elsevier]

Chronic antiepileptic therapy with valproic acid (VPA) is associated with increased body weight and insulin resistance in adults and children. Attempts to determine the underlying pathophysiologic mechanisms have failed. Adipocytokines have recently been defined as a link between glucose and fat metabolism. We herein demonstrate that VPA-associated overweight is accompanied by lower adiponectin and higher leptin concentrations in children. The absence of any relationship with visfatin concentration does not suggest a role of this novel insulin-mimetic hormone in VPA-associated metabolic alterations. Therefore, adiponectin and leptin but not visfatin may be considered as potential regulators of glucose and fat metabolism during VPA-therapy. [ABSTRACT FROM AUTHOR]

Therapy resistance represents a major problem for disease management in oncology. Histone deacetylase inhibitors (HDACi) have been shown to modulate the cell cycle, to induce apoptosis and to sensitize cancer cells for other chemotherapeutics. Our study shows that the HDACi valproic acid (VPA) and the ribonucleotide reductase inhibitor hydroxyurea (HU) potentiate the pro-apoptotic effects of each other towards several cancer cell lines. This correlates with the HU-induced degradation of the cyclin-dependent kinase inhibitors (CDKI) p21 and p27, mediated by the proteasome or caspase-3. Moreover, we found that caspase-3 activation is required for VPA-induced apoptosis. Remarkably, p21 and p27 can confer resistance against VPA and HU. Both CDKI interact with caspase-3 and compete with other caspase-3 substrates. Hence, p21 and p27 may contribute to chemotherapy resistance as apoptosis inhibitors. Since the biological effects of VPA and HU could be achieved at concentrations used in current treatment protocols, the combined application of these compounds might be considered as a potential strategy for cancer treatment.Oncogene (2008) 27, 732–740; doi:10.1038/sj.onc.1210677; published online 23 July 2007 [ABSTRACT FROM AUTHOR]

Abstract: Gulland''s [Gulland, J.A., 1965. Estimation of mortality rates. Annex to Arctic Fisheries Working Group Report (meeting in Hamburg, January 1965). ICES, C.M. 1965, Doc. No. 3 (mimeographed)] virtual population analysis (VPA) is commonly used for studying the dynamics of harvested fish populations. However, it necessitates the solving of a nonlinear equation for the instantaneous rate of fishing mortality of the fish in a population. Pope [Pope, J.G., 1972. An investigation of the accuracy of Virtual Population Analysis using cohort analysis. ICNAF Res. Bull. 9, 65–74. Also available in D.H. Cushing (ed.) (1983), Key Papers on Fish Populations, p. 291–301, IRL Press, Oxford, 405 p.] eliminated this necessity in his cohort analysis by approximating its underlying age- and time-dependent population model. His approximation has since become one of the most commonly used age- and time-dependent fish population models in fisheries science. However, some of its properties are not well understood. For example, many assert that it describes the dynamics of a fish population, from which the catch of fish is taken instantaneously in the middle of the year. Such an assertion has never been proven, nor has its implied instantaneous rate of fishing mortality of the fish of a particular age at a particular time been examined, nor has its implied catch equation been derived from a general catch equation. In this paper, we prove this assertion, examine its implied instantaneous rate of fishing mortality of the fish of a particular age at a particular time, derive its implied catch equation from a general catch equation, and comment on how to structure an age- and time-dependent population model to ensure its internal consistency. This work shows that Gulland''s (1965) virtual population analysis and Pope''s (1972) cohort analysis lie at the opposite end of a continuous spectrum as a general model for a seasonally occurring fishery; Pope''s (1972) approximation implies an infinitely large instantaneous rate of fishing mortality of the fish of a particular age at a particular time in a fishing season of zero length; and its implied catch equation has an undefined instantaneous rate of fishing mortality of the fish in a population, but a well-defined cumulative instantaneous rate of fishing mortality of the fish in the population. This work also highlights a need for a more careful treatment of the times of start and end of a fishing season in fish population models. [Copyright &y& Elsevier]

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Abstract: Valproic acid (VPA), a mood stabilizer and anticonvulsant, has a variety of neurotrophic functions; however, less is known about how VPA regulates neurite outgrowth. Here, using N1E-115 neuroblastoma cells as the model, we show that VPA upregulates Gadd45a to trigger activation of the downstream JNK cascade controlling neurite outgrowth. VPA induces the phosphorylation of c-Jun N-terminal kinase (JNK) and the substrate paxillin, while VPA induction of neurite outgrowth is inhibited by JNK inhibitors (SP600125 and the small JNK-binding peptide) or a paxillin construct harboring a Ser 178-to-Ala mutation at the JNK phosphorylation. Transfection of Gadd45a, acting through the effector MEKK4, leads to the phosphorylation of the JNK cascade. Conversely, knockdown of Gadd45a with siRNA reduces the effect of VPA. Taken together, these results suggest that upregulation of Gadd45a explains one of the mechanisms whereby VPA induces the neurotrophic effect, providing a new role of Gadd45a in neurite outgrowth. [Copyright &y& Elsevier]

Study Objective. To describe the dose-concentration relationship of a continuous intravenous infusion of valproic acid (VPA) in pediatric patients when a dosing protocol is used. Design. Retrospective and concurrent chart review. Setting. Tertiary care, 473-bed, academic medical center with a 120-bed, dedicated children's hospital. Patients. Twenty-six pediatric patients (< 18 yrs old) who received VPA according to the protocol for continuous intravenous infusions between January 1, 2004, and March 31, 2006, identified by using a pharmacy order-entry system. Measurements and Main Results. Patient demographics, VPA treatment regimens, clinical responses, and safety data were recorded and analyzed. Median patient age was 8.5 years (range 1.4-16 yrs). Approximately two thirds received VPA for seizures, and one third for migraines. Patients were given a mean ± SD VPA loading dose of 28.5 ± 5.2 mg/kg followed by a continuous infusion rate of 1 ± 0.2 mg/kg/hour. Mean ± SD serum concentration measured 4.5 ± 1.6 hours after the loading dose was 83.3 ± 22.8 µg/ml. Steady-state concentration at 23.3 ± 3.0 hours after the start of the continuous infusion was 80.0 ± 26.0 µg/ml. Postload and steady-state serum concentrations were within the target concentration of 50-100 µg/ml in 77% and 69% of patients, respectively. On further analysis, when the target range was expanded to 50-125 µg/ml (125 µg/ml was deemed acceptable if no adverse effects were noted), 89% and 92% of patients, respectively, had postload and steady-state VPA serum concentrations within this range. The response rate was excellent, with nearly 85% of patients achieving a complete or partial response to therapy. Adverse effects were generally mild and uncommon. Conclusions. The continuous-infusion protocol permitted rapid intravenous loading of VPA in pediatric patients while minimizing adverse events and achieving concentrations in the upper region of the therapeutic range. [ABSTRACT FROM AUTHOR]

Two of the most significant developments in fisheries science are the single species virtual population analysis (SSVPA) and multi-species virtual population analysis (MSVPA). Since its development, MSVPA and its variants have been used in fish population studies, fish stock assessment, and the management of the fisheries in many parts of the world, including the North Sea, the Baltic Sea, the Barents Sea, the Bering Sea, Georges Bank, and the Benguela Current, and have been accepted as routine and essential tools for making efficient use of the world''s major fisheries resources for food production, and for conserving and managing those resources. However, serious questions arise from the fact that some of their equations are “borrowed” straight from SSVPA, except for adding a species index. In this paper, I derive the fundamental equations of MSVPA and its variants as a system of ordinary differential equations (if the ages of fish are discrete) or as a system of first order partial differential–integral equations (if the ages of fish are continuous), both subject to appropriate constraints and boundary conditions (biological observations and data). Their formulation as well known mathematical problems has not only revealed their mathematical nature and hence laid the foundation for their speedy solution by use of a great variety of known and readily available mathematical techniques, but also revealed the logical inconsistency in the currently used MSVPA and its variants. This inconsistency highlights an urgent need to revise all past work on MSVPA and its variants, by replacing the existing equations of MSVPA and its variants with the fundamental equations derived above. Finally, I discuss (1) the conversion of data on the stomach contents of fish of different ages and of different species into their coefficients of suitability, (2) two possible extensions of the present work, (3) its general ecological and biological significance as a much needed practical method or routine for parameterizing a system of age- and time-dependent or more general Lotka–Volterra equations to understand the underlying mechanisms for the rapid changes of the ecosystems and for us to maintain a harmonious co-existence within a biological system, and (4) its significance to several areas of fisheries science, including food production, effective use and management of fisheries resources, marine and freshwater conservation, and the maintenance of a healthy aquatic environment. [Copyright &y& Elsevier]

Summary: Five oral formulations of valproic acid (VPA)/divalproex sodium are approved and commonly used in the US for treatment of epilepsy, mania/bipolar disorder and migraine prophylaxis. These formulations have unique pharmacokinetic and formulation characteristics and are designed to treat distinct patient populations. We compared the absorption characteristics of all five oral VPA/divalproex formulations currently available in the US. Plasma VPA concentration–time profiles, following single oral dose (250mg) administration of five VPA/divalproex formulations under fasting conditions, from three pharmacokinetic studies in healthy subjects (N =9–15 each) were compared. The five VPA/divalproex formulations demonstrated marked absorption differences. The rate of absorption, as characterized by maximum concentration (C max) and time to C max (T max), may be rank-ordered as: VPA syrup (34.2mg/L, 0.9h)>VPA capsule (31.4mg/L, 2.2h)>divalproex sodium sprinkle capsule (20.7mg/L, 4.0h; lag-time≅1h)≅divalproex sodium enteric-coated delayed-release tablet (26.0mg/L, 3.4h; lag-time≅2h)>divalproex sodium extended-release (divalproex-ER) tablet (11.8mg/L, 19.7h). Divalproex-ER had ∼11% lower exposure (AUC). The comparable AUC across the five formulations, when corrected for bioavailability differences, demonstrates that formulation primarily affects the drug-release and in vivo absorption of VPA. Only divalproex-ER demonstrated true sustained-release characteristics. [Copyright &y& Elsevier]

Oncolytic adenoviruses preferentially replicate in and lyse tumor cells. However, their application to cancer gene therapy has been complicated by the low levels of coxsackie and adenovirus receptor (CAR) expressed in many solid tumors. Histone deacetylase inhibitors (HDACIs) significantly up-regulate CAR expression in tumor cells and have additional antineoplastic activities. Therefore, there is a clear rationale for the combination of HDACIs and oncolytic adenoviral gene therapy. We present evidence that HDACI treatment significantly inhibits adenoviral replication, viral burst, and tumor cell kill. Valproic acid (VPA), a well-established HDACI, inhibits adenoviral replication late in the viral life cycle. We hypothesized that VPA induction of the cell-cycle-regulating protein p21WAF1/CIP1 may be partly responsible for this activity. We demonstrate that p21WAF1/CIP1 expression alone limits viral replication and decreases viral titers in different cancer cell models. We also demonstrate that VPA and replicating adenovirus mutually inhibit each other's ability to kill cells, independent of p21WAF1/CIP1 expression. These results not only identify the importance of p21WAF1/CIP1 in the biology of adenoviral replication, but also suggest that oncolytic adenoviral gene therapy will be inhibited rather than enhanced by VPA (HDACI) treatment.Molecular Therapy (2006) 14, 768–778; doi: 10.1016/j.ymthe.2006.07.009 [ABSTRACT FROM AUTHOR]

Abstract: The anti-epileptic drug valproic acid harbors anti-tumoral activity in solid and leukemic tumor cell models and is currently evaluated in clinical trials. However, the plasma trough concentrations obtained in patients by common anti-epileptic dose regimens are below concentrations required for exerting anti-tumor effects in vitro. Here, we describe the identification of three novel valproic acid derivatives with superior differentiation-inducing and anti-proliferative activities in K562 bcr/abl-positive chronic myeloid leukemia cells and HL60 promyelocytic leukemia cells at achievable therapeutic VPA concentrations. These compounds reveal potent inhibition of histone deacetylase activity, induction of p21Cip/Waf expression as well as low toxicity on CD34+ bone marrow cells. [Copyright &y& Elsevier]

Abstract: Valproic acid (VPA), a histone deacetylase inhibitor, causes differentiation in different cell lines and in a cell-specific manner; yet, its effect on megakaryocytic (MK) differentiation has not been studied. We evaluated whether VPA induces MK differentiation in a UT-7 cell line through histone acetylation in the GpIIIa gene region and activation of the ERK pathway. UT-7 cells, derived from megakaryoblastic leukemia, were treated with VPA at various concentrations, and the expression of differentiation markers as well as the gene expression profile was assessed. Flow cytometry, immunoblot analysis, and RT-PCR demonstrated that VPA induced the expression of the early MK markers GpIIIa (CD61) and GpIIb/IIIa (CD41) in a dose-dependent manner. The VPA-treated cells showed hyperacetylation of the histones H3 and H4; in particular, histone acetylation was found to have been associated with CD61 expression, in that the GpIIIa promoter showed H4 hyperacetylation, as demonstrated by the chromatin immunoprecipitation assay. Furthermore, activation of the ERK pathway was involved in VPA-mediated CD61/CD41 expression and in cell adhesion, as demonstrated by using the MEK/ERK inhibitor U0126. In conclusion, the capacity of VPA to commit UT-7 cells to MK differentiation is mediated by its inhibitory action on HDAC and the long-lived activation of ERK1/2. [Copyright &y& Elsevier]

Objective: To examine provider and type variation in social support (SS) for activity. Methods: Three hundred sixty-three fifth to eighth-grade students completed a questionnaire assessing self-reported activity and social support (SS) from 3 providers: morn, dad, and peers. Important covariates of activity were included in the analysis: age, BMI, sex, and maturation. Results: Structural equation modeling indicated peers, transportation, and praise affected activity levels. Boys reported greater SS than girls did. Maturation, age, and BMI exhibited unique affects on SS. Conclusions: Increasing positive feedback, transportation to places to be active, and peer support may prove advantageous in improving activity levels in this age-group. [ABSTRACT FROM AUTHOR]

The hydro-acoustic target strength (TS) of herring (Clupea harengus L.) was estimated from the catch composition of 19 pelagic-trawl hauls and from simultaneous recordings with a split-beam, 38kHz echosounder. The data were collected in September 2000 during a Bothnian Sea survey in the northern Baltic Sea. The dependence of TS (in dB) on fish length (L, cm) was modelled with the equation TS=alog10 L+b. The fitted model was TS=16.8log10 L−60.0. With a predefined slope of 20 the TS vs. log-fish length relationship was TS=20log10 L−63.9. The analyses suggested that TS was higher in the Bothnian Sea than is assumed in most studies in the Baltic Sea. Applying the revised TS–length dependence considerably enhanced the agreement between the biomass estimates from hydroacoustics and those from a catche-at-age analysis (VPA). [Copyright &y& Elsevier]

Abstract: This study describes the historical evolution of the biomass, fishing mortality per age group, annual recruitment, and catchability of the Campeche Bank red grouper population. This fishery is based on three fleets (the Mexican Minor, the Mexican Major or Industrial, and the Cuban) with different capacities, areas of operation, and targeting of different age groups. During the last 10 years, the Minor fleet expanded, resulting in some overlapping with the other fleets areas. The biomass of the population of the red grouper in the Campeche Bank has decreased between 1986 and 2000. This decrease is evident from the commercial landings (from 14,410 to 9797t) and in CPUE from independent research surveys (from 3.8 to 1.5kg/100 hooks). The size of the spawning stock has decreased 25% since the beginning of the period, as well as the recruitment (from 24 to 11 million, 1–2 years old), while the catchability coefficient has increased (from 0.2 to 0.4). [Copyright &y& Elsevier]

Neuroblastoma (NB), a sympathetically derived childhood tumour, shows characteristics of neuronal precursor cells, suggesting a halted differentiation process. We have previously shown that the Notch signalling cascade, a key player during normal neurogenesis, also might be involved in NB differentiation. Valproic acid (VPA), a well-tolerated antiepileptic drug, has been shown to induce differentiation and cell death of NB cells, possibly associated with its recently described HDAC inhibiting activity. Stimulation of NB cells with VPA led to increased cell death and phenotypic changes associated with differentiation, that is, neurite extension and upregulation of neuronal markers. VPA treatment also led to an activated Notch signalling cascade as shown by increased levels of intracellular Notch-1 and Hes-1, mimicking the initial phase of induced differentiation. These results reinforce that VPA potentially could be used in differentiation therapy of NB and that the effects in part could be a consequence of interference with the Notch signalling cascade. [ABSTRACT FROM AUTHOR]

Pärnu Bay is the most important fishing ground in Estonian coastal fishery where until recently, pikeperch (Stizostedion lucioperca) was, after the Baltic herring (Clupea harengus membras), the second most important commercial fish. Exploitation of pikeperch stock in Pärnu Bay is analysed in the period of the Soviet planned economy that was characterized by low market demand and fixed low price for fish, and the free market conditions of high demand and high prices for fish. The consequences of the different management regimes of the pikeperch stock at different economic situations are discussed. Under free market economy conditions, the average fishing mortality of the pikeperch was more than twice as high as under the planned economy. As a result, several strong year-classes hatched in the 1990s were fished out before legally entering the fishery. Catches decreased sharply after 1997 and the pikeperch fishery was closed in 2000. Abundant year-classes contributed to an increase in the spawning stock biomass in the period of the Soviet planned economy. Until the transition to a free market economy the fishing mortality rate was close to optimal, but since then growth-overfishing of the stock has led to an annual loss of at least 38% of the potential long-term catch. [Copyright &y& Elsevier]

The teratogenic activity of xenobiotics is usually investigated by examinating visceral and skeletal abnormalities of term fetuses. Although the rodent fetal skeleton is only partially ossified, the single stain for bone is the most commonly used method in routine teratology testing, while the double stain for evaluation of both bone and cartilage is often used only in basic research. The present work compares data obtained from rat fetuses using the two methods after exposure to the teratogenic agent sodium valproate at specific embryonic stages of development. Pregnant rats were treated with 400 mg/kg sodium valproate and sacrificed at term of pregnancy.Even if both methods were able to identify sodium valproate as a teratogenic molecule, correct and complete interpretation of data was possible only by using the double stain. Our results show the inability of the single stain to correctly discriminate between major and minor abnormalities. [Copyright &y& Elsevier]

The data sets required for constructing age-based models for the Northeast Arctic cod stock are extended back to 1930 and critically reviewed. The full data set (1930–1994) is interpreted by both a standard virtual population analysis (VPA) and a version that allows for cannibalism. The resulting extended time-series of population abundance-at-age is used to reconsider the parent stock, temperature, and predation relationships described earlier. Results from the version of the VPA with cannibalism based on the new data confirm the earlier findings that temperature and spawning-stock biomass had a significant positive effect on recruitment. This is not the case with the extended time-series as interpreted by the standard VPA because, while significant temperature and juvenile predation effects are still found, a parent stock effect is no longer statistically significant. Moreover, the general level of explanation provided by the multiple regression is far less with the extended time-series. [ABSTRACT FROM PUBLISHER]

Very long-term cyclic oxidation behavior of Re108 and In939 with and without a protective coating was evaluated at 980 and 870 °C, respectively. Re108 and In939 without a protective coating began to show a rapid weight loss at 3000 h due to scale spallation, indicating the need for an oxidation protective coating for longer than thousands of hours of oxidative life. NiAl-base coatings of a vapor phase aluminide (VPA), a pack aluminide (CODEP), and a slurry paint aluminide (SERMALOY J) were applied on Re108 and In939. The VPA and CODEP on Re108 and all three coatings on In939 showed excellent cyclic oxidation resistance out to 10,000 h. Coated alloys were annealed in an inert atmosphere to determine the loss of Al from the coating into the alloy substrate through diffusion. The Al loss from the coating through diffusion was twice as great as the Al loss through oxidation after 10,000 h of cyclic exposure. The oxidation life of VPA-coated Re108 was estimated by calculating the amount of Al initially available for protective oxidation and the amount of Al lost through oxidation and diffusion. [ABSTRACT FROM AUTHOR]

In vitro models of human liver disease often fail to mimic the complex 3D structures and cellular organizations found in vivo . Precision cut liver slices (PCLS) retain the complex physiological architecture of the native liver and therefore could be an exceptional in vitro liver model. However, the production of PCLS induces a spontaneous culture-induced fibrogenic reaction, limiting the application of PCLS to anti-fibrotic compounds. Our aim was to improve PCLS cultures to allow compound-induced fibrosis induction. Hepatotoxicity in PCLS cultures was analyzed by lactate dehydrogenase leakage and albumin secretion, while fibrogenesis was analyzed by qRT-PCR and western blot for hepatic stellate cell (HSC) activation markers and collagen 6 secretion by enzyme-linked immunosorbent assays (ELISA). We demonstrate that supplementation of 3 mm mouse PCLS cultures with valproate strongly reduces fibrosis and improves cell viability in our PCLS cultures for up to 5 days. Fibrogenesis can still be induced both directly and indirectly through exposure to TGFβ and the hepatotoxin acetaminophen, respectively. Finally, human PCLS cultures showed similar but less robust results. In conclusion, we optimized PCLS cultures to allow for drug-induced liver fibrosis modeling., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Dewyse, De Smet, Verhulst, Eysackers, Kunda, Messaoudi, Reynaert and van Grunsven.)

OBJECTIVES: Internal tandem duplications (ITDs) of the Fms-like tyrosine kinase 3 (FLT3) represent the most frequent molecular aberrations in acute myeloid leukemia (AML) and are associated with an inferior prognosis. The pattern of downstream activation by this constitutively activated receptor tyrosine kinase is influenced by the localization of FLT3-ITD depending on its glycosylation status. Different pharmacological approaches can affect FLT3-ITD-driven oncogenic pathways by the modulation of FLT3-ITD localization. AIMS: The objective of this study was to investigate the effects of N-glycosylation inhibitors (tunicamycin or 2-deoxy-D-glucose) or the histone deacetylase inhibitor valproic acid (VPA) on FLT3-ITD localization and downstream activity. We sought to determine the potential differences between the distinct FLT3-ITD variants, particularly concerning their susceptibility towards combined treatment by addressing either N-glycosylation and the heat shock protein 90 (HSP90) by 17-AAG, or by targeting the PI3K/AKT/mTOR pathway by rapamycin after treatment with VPA. METHODS: Murine Ba/F3 leukemia cell lines were stably transfected with distinct FLT3-ITD variants resulting in IL3-independent growth. These Ba/F3 FLT3-ITD cell lines or FLT3-ITD-expressing human MOLM13 cells were exposed to tunicamycin, 2-deoxy-D-glucose or VPA, and 17-AAG or rapamycin, and characterized in terms of downstream signaling by immunoblotting. FLT3 surface expression, apoptosis, and metabolic activity were analyzed by flow cytometry or an MTS assay. Proteome analysis by liquid chromatography–tandem mass spectrometry was performed to assess differential protein expression. RESULTS: The susceptibility of FLT3-ITD-expressing cells to 17-AAG after pre-treatment with tunicamycin or 2-deoxy-D-glucose was demonstrated. Importantly, in Ba/F3 cells that were stably expressing distinct FLT3-ITD variants that were located either in the juxtamembrane domain (JMD) or in the tyrosine kinase 1 domain (TKD1), response to the sequential treatments with tunicamycin and 17-AAG varied between individual FLT3-ITD motifs without dependence on the localization of the ITD. In all of the FLT3-ITD cell lines that were investigated, incubation with tunicamycin was accompanied by intracellular retention of FLT3-ITD due to the inhibition of glycosylation. In contrast, treatment of Ba/F3-FLT3-ITD cells with VPA was associated with a significant increase of FLT3-ITD surface expression depending on FLT3 protein synthesis. The allocation of FLT3 to different cellular compartments that was induced by tunicamycin, 2-deoxy-D-glucose, or VPA resulted in the activation of distinct downstream signaling pathways. Whole proteome analyses of Ba/F3 FLT3-ITD cells revealed up-regulation of the relevant chaperone proteins (e.g., calreticulin, calnexin, HSP90beta1) that are directly involved in the stabilization of FLT3-ITD or in its retention in the ER compartment. CONCLUSION: The allocation of FLT3-ITD to different cellular compartments and targeting distinct downstream signaling pathways by combined treatment with N-glycosylation and HSP90 inhibitors or VPA and rapamycin might represent new therapeutic strategies to overcome resistance towards tyrosine kinase inhibitors in FLT3-ITD-positive AML. The treatment approaches addressing N-glycosylation of FLT3-ITD appear to depend on patient-specific FLT3-ITD sequences, potentially affecting the efficacy of such pharmacological strategies. [ABSTRACT FROM AUTHOR]

Myelin consists of several layers of tightly compacted membranes that form an insulating sheath around axons. These membranes are highly enriched in cholesterol, which is essential for the myelination process. Proper myelination is crucial for various neurophysiological functions while demyelination may cause CNS disease, such as multiple sclerosis (MS). Recent studies demonstrated that demyelination occurs not only in the white matter but also in the grey matter, such as the hippocampus, which may cause cognitive deficits and mental disorders. Valproic acid (VPA) is an anticonvulsant agent prescribed for the treatment of epilepsy and seizure. Recently, VPA was reported to alter cholesterol metabolism in neural cells, suggesting that it may play an important role in myelin biogenesis. Here in this study, we found significant demyelination in the hippocampus of the mouse cuprizone model, which is accompanied by reduced cholesterol biosynthesis and increased anxiety-like behavior. VPA treatment, however, suppressed cuprizone-induced hippocampal demyelination and anxiety-like behavior by promoting cholesterol biosynthesis. These data identify an important role of VPA in the hippocampal demyelination process and the hippocampal demyelination-related behavior deficit via regulation of cholesterol biosynthesis, which provides new insights into the mechanisms of VPA as a protective agent against CNS demyelination. • Cuprizone treatment induces hippocampal demyelination and anxiety-like behavior • Cuprizone treatment suppresses hippocampal cholesterol biosynthesis • Valproic acid promotes hippocampal cholesterol biosynthesis in cuprizone-induced demyelination model • Valproic acid protects against cuprizone-induced hippocampal demyelination • Valproic acid suppresses cuprizone-induced anxiety-like behavior [ABSTRACT FROM AUTHOR]

Autism Spectrum Disorder (ASD) is one of the most frequently diagnosed neurodevelopmental disorders, characterized among others by impairments in social interactions and repetitive behavior. According to one of the leading hypotheses about its origin, ASD is caused by the imbalance of excitatory and inhibitory circuit activity. ASD-related morphological and functional changes can be observed in several brain regions i.e., in the prefrontal cortex and the hippocampus. It is well-established that prenatal valproic-acid (VPA) exposure of rats on day 12.5 leads to neurodevelopmental alterations with autism-like clinical and behavioral symptoms. The aim of this study was to investigate potential changes in the excitability of neuronal networks and individual neurons of the hippocampus elicited by prenatal VPA treatment. As there are marked sex differences in ASD, offspring of both sexes were systematically tested, using two different age groups, to elucidate eventual differences in neurodevelopment after VPA treatment. Excitatory connections and long-term synaptic plasticity as well as intrinsic excitability of CA1 pyramidal cells were examined. Pregnant female Wistar rats received saline or 500 mg/kg VPA i. p. on gestation day 12.5. Brain slices of 6-week-old and 3-month-old offspring were investigated using extra- and intracellular electrophysiological techniques. Field potential- and whole-cell patch clamp recordings were carried out to measure network excitability and single cell activity in the CA1 region hippocampus. Enhanced excitability of hippocampal networks was detected in the 6-week-old VPA-treated male rats; however, this change could not be observed in 3-month-old males. Intrinsic excitability of single neurons, however, was increased in 3-month-old males. In 6-week-old treated females, the most prominent effect of VPA was an increase in voltage sag, to a similar degree to the neurons of the older age group. In 3-month-old females, a network excitability increase could be demonstrated, in a lesser degree than in younger males. It can be concluded, that VPA treatment had diverse effects on hippocampal excitability depending on the sex and the age of the animals. We found that certain alterations manifested in 6-week-old rats were compensated later, on the other hand, other changes persisted until the age of 3 months., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Bódi, Májer, Kelemen, Világi, Szűcs and Varró.)

In compliance to animal welfare 3Rs principle there is a great demand for refined tests alternative to classical mammal teratogenicity tests. We propose a refined alternative amphibian method (R-FETAX) to evaluate chemical induced embryotoxicity. The human foetal valproate spectrum disorder (FVSD) characteristics are morphological defects (including cranio-facial, neural tube defects) and behavioural alterations due to valproate (VPA) exposure in pregnancy. Vertebrate assays to evaluate FVSD include classical and alternative mammal (implying adult sacrifice), and non-mammal developmental models (zebrafish, amphibians, chick). Among these latter only zebrafish assays report in the same test both morphological and behavioural examinations. Compared to zebrafish, the amphibian Xenopus laevis excels having a more comparable organ development and morphology to mammalian systems. We used X. laevis embryos exposed during developmental specific windows to VPA therapeutic concentrations. Different VPA effects were observed depending on the exposure window: concentration-related embryo-lethal and teratogenic effects (neural tube, facial, tail defects) were observed in groups exposed at the organogenetic phylotypic stages. Neurobehavioral deficits were described using a functional swimming test at the highest VPA concentration exposure during the phylotypic stages and at any concentration during neurocognitive competent stages. Malformations were compared to those obtained in a mammalian assay (the rat post-implantation whole embryo culture method, WEC), that we used in the past to evaluate VPA teratogenicity. R-FETAX and WEC data were modelled and their relative sensitivity was calculated. We suggest the amphibian R-FETAX as a refined windowed alternative test for the evaluation of chemicals inducing both morphological and behavioural anomalies, including VPA., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Directed differentiation of mouse embryonic stem cells (mESCs) or induced pluripotent stem cells (iPSCs) provides powerful models to dissect the molecular mechanisms leading to the formation of specific cell lineages. Treatment with histone deacetylase inhibitors can significantly enhance the efficiency of directed differentiation. However, the mechanisms are not well understood. Here, we use CUT&RUN in combination with ATAC-seq to determine changes in both histone modifications and genome-wide chromatin accessibility following valproic acid (VPA) exposure. VPA induced a significant increase in global histone H3 acetylation (H3K56ac), a core histone modification affecting nucleosome stability, as well as enrichment at loci associated with cytoskeletal organization and cellular morphogenesis. In addition, VPA altered the levels of linker histone H1 subtypes and the total histone H1/nucleosome ratio indicative of initial differentiation events. Notably, ATAC-seq analysis revealed changes in chromatin accessibility of genes involved in regulation of CDK serine/threonine kinase activity and DNA duplex unwinding. Importantly, changes in chromatin accessibility were evident at several key genomic loci, such as the pluripotency factor Lefty, cardiac muscle troponin Tnnt2, and the homeodomain factor Hopx, which play critical roles in cardiomyocyte differentiation. Massive parallel transcription factor (TF) footprinting also indicates an increased occupancy of TFs involved in differentiation toward mesoderm and endoderm lineages and a loss of footprints of POU5F1/SOX2 pluripotency factors following VPA treatment. Our results provide the first genome-wide analysis of the chromatin landscape following VPA-induced differentiation in mESCs and provide new mechanistic insight into the intricate molecular processes that govern departure from pluripotency and early lineage commitment., (© 2021. The Author(s).)

Given the sex differences evident in the prevalence of autism, there is an increased awareness of the importance of including females in autism research to determine sexual dimorphism and sex-specific treatments. Cannabinoids and endocannabinoid modulators have been proposed as potential novel treatments for autism-related symptoms; however, few studies to date have examined if these pharmacological agents elicit sex-specific effects. The aim of the present study was to use the valproic acid (VPA) model of autism to compare the behavioural responses of male and female rats and examine the effects of increasing endocannabinoid tone on the behavioural responses of VPA-exposed female rats. These data revealed that VPA-exposed male, but not female, rats exhibit reduced social responding in the three-chamber and olfactory habituation/dishabituation (OHD) test during adolescence. In comparison, VPA-exposed female, but not male, adolescent rats exhibited anxiety-like behaviour in the elevated plus maze (EPM) and open field test (OFT). In VPA-exposed female rats, increasing 2-AG levels augmented anxiety-like behaviour in the EPM and OFT, while increasing AEA levels reduced stress coping behaviour in the swim stress test. These data highlight sexual dimorphic behaviours in the VPA model and indicate that enhancing endocannabinoid levels may exacerbate negative affective behaviour in VPA-exposed females. Thus, considerations should be paid to the possible sex-specific effects of cannabinoids for the treatment of symptoms associated with autism. [ABSTRACT FROM AUTHOR]

The eastern stock of gemfish in south-eastern Australia is currently assessed to be overfished and to be depleted below the performance criterion established by the Australian Fisheries Management Authority (AFMA). Assessments of the stock indicate that there was a substantial decline in abundance during the late 1970s and early 1980s and that the year classes spawned at the end of the 1980s were much weaker than expected from the (estimated) stock–recruitment relationship. The performances of a variety of alternative management procedures are contrasted. The factors considered in the operating models include uncertainty about historical catches, the comparability of recent survey estimates, the form of the stock–recruitment relationship, whether variations in recruitment about the stock–recruitment relationship are auto-correlated, and the quantity and quality of the data available for assessment purposes. The management procedures differ in terms of their data needs (survey data only, survey and age-composition data) and their target levels. The results indicate that, even though yields from the fishery are likely to be low, the benefits of conducting annual surveys exceed the costs. The value of collecting age-composition data is less clear. Management procedures based on Virtual Population Analysis achieve more variable catches and are less likely to satisfy AFMA performance criteria than management procedures based on a Schaefer production model, but they achieve higher levels of “guaranteed” catch for the industry. [ABSTRACT FROM PUBLISHER]

A simple model relating catchability to maturity is presented, which allows for computation of annual age-specific correction factors for groundfish survey indices. The model is based on the hypothesis that mature fish are less catchable than immature fish during the spawning season and are therefore less available to groundfish surveys carried out during that period. The effect modelled is an interaction effect – its operation requires both a change in catchability at maturity and temporal changes in maturity at age in the stock. In recent years, assessments of the Icelandic cod stock have relied on VPAs calibrated (tuned) with bottom trawl c.p.u.e. data. The c.p.u.e. data are from the commercial trawler fleet and from the Marine Research Institute's annual groundfish survey conducted in March, covering the entire distribution area of the stock around Iceland. At the time of the survey, most of the year's spawners have migrated towards the spawning grounds. Independent data from commercial catches indicate that the proportions of fish mature at age in the Icelandic cod stock have increased substantially in recent years. Furthermore, comparison of proportions mature in the catches with survey indices for mature and immature fish indicate that immature fish are substantially more catchable than mature fish of the same age. The effects of changes in proportion mature on estimated stock numbers are discussed with reference to limitations in the available data. [ABSTRACT FROM PUBLISHER]

The analysis of multiple time series of indices of recruitment to fish stocks by means of calibration regression is discussed, together with the use of the relationships so fitted for the prediction of year class strength. A simple method for the combination of the estimates derived from different index series using inverse variance weighted averages is proposed, and methods for the estimation of the overall error in the prediction are discussed. The method used has been shown to perform well in simulation tests, and is well adapted for use on real datasets with time series of variable length and missing data. It has been implemented in a computer program (RCT3, superseding RCRTINX2) which is available for operational use, and has been endorsed by the ICES Working Group on the Methods of Fish Stock Assessment as being satisfactory for operational use until more complex methods have been shown to have superior performance.opyright 1997 International Council for the Exploration of the Sea [ABSTRACT FROM PUBLISHER]

The approach suggested is in the class of cohort methods; it is a new technique for processing catch-at-age data on species having short (within a year) periods of fishery. The method can also be regarded as an approximation to more general conditions when fishery varies continuously during the year. In many cases it enables a more complete extraction of information on exploited populations and fishery from the catch-at-age matrices, including the natural mortality coefficient and terminal fishing parameters, without using any auxiliary data (survey data, fishing effort series etc.). A number of numerical experiments using simulated data illustrate the methodology and demonstrate the merits of the suggested method. [ABSTRACT FROM PUBLISHER]