Musaad A. Alshammari

Parallel fiber to Purkinje cell synaptic impairment in a mouse model of spinocerebellar ataxia type 27

Genetically inherited mutations in the fibroblast growth factor 14 (FGF14) gene lead to spinocerebellar ataxia type 27 (SCA27), an autosomal dominant disorder characterized by heterogeneous motor and cognitive impairments. Consistently, genetic deletion of Fgf14 in Fgf14−/− mice recapitulates salient features of the SCA27 human disease. In vitro molecular studies in cultured neurons indicate that the FGF14F145S SCA27 allele acts as a dominant negative mutant suppressing the FGF14 wild type function and resulting in inhibition of voltage-gated Na+ and Ca2+ channels. To gain insights in the cerebellar deficits in the animal model of the human disease, we applied whole-cell voltage-clamp in the acute cerebellar slice preparation to examine the properties of parallel fibers (PF) to Purkinje neuron synapses in Fgf14−/− mice and wild type littermates. We found that the AMPA receptor-mediated excitatory postsynaptic currents evoked by PF stimulation (PF-EPSCs) were significantly reduced in Fgf14−/− animals, while short-term plasticity, measured as paired-pulse facilitation (PPF), was enhanced. Measuring Sr2+-induced release of quanta from stimulated synapses, we found that the size of the PF-EPSCs was unchanged, ruling out a postsynaptic deficit. This phenotype was corroborated by decreased expression of VGLUT1, a specific presynaptic marker at PF-Purkinje neuron synapses. We next examined the mGluR1 receptor-induced response (mGluR1-EPSC) that under normal conditions requires a gradual build-up of glutamate concentration in the synaptic cleft, and found no changes in these responses in Fgf14−/− mice. These results provide evidence of a critical role of FGF14 in maintaining presynaptic function at PF-Purkinje neuron synapses highlighting critical target mechanisms to recapitulate the complexity of the SCA27 disease.

Genetic deletion of fibroblast growth factor 14 recapitulates phenotypic alterations underlying cognitive impairment associated with schizophrenia.

Cognitive processing is highly dependent on the functional integrity of gamma-amino-butyric acid (GABA) interneurons in the brain. These cells regulate excitability and synaptic plasticity of principal neurons balancing the excitatory/inhibitory tone of cortical networks. Reduced function of parvalbumin (PV) interneurons and disruption of GABAergic synapses in the cortical circuitry result in desynchronized network activity associated with cognitive impairment across many psychiatric disorders, including schizophrenia. However, the mechanisms underlying these complex phenotypes are still poorly understood. Here we show that in animal models, genetic deletion of fibroblast growth factor 14 (Fgf14), a regulator of neuronal excitability and synaptic transmission, leads to loss of PV interneurons in the CA1 hippocampal region, a critical area for cognitive function. Strikingly, this cellular phenotype associates with decreased expression of glutamic acid decarboxylase 67 (GAD67) and vesicular GABA transporter (VGAT) and also coincides with disrupted CA1 inhibitory circuitry, reduced in vivo gamma frequency oscillations and impaired working memory. Bioinformatics analysis of schizophrenia transcriptomics revealed functional co-clustering of FGF14 and genes enriched within the GABAergic pathway along with correlatively decreased expression of FGF14, PVALB, GAD67 and VGAT in the disease context. These results indicate that Fgf14−/− mice recapitulate salient molecular, cellular, functional and behavioral features associated with human cognitive impairment, and FGF14 loss of function might be associated with the biology of complex brain disorders such as schizophrenia.

Improved Methods for Fluorescence Microscopy Detection of Macromolecules at the Axon Initial Segment

The axonal initial segment (AIS) is the subcellular compartment required for initiation of the action potential in neurons. Scaffolding and regulatory proteins at the AIS cluster with ion channels ensuring the integrity of electrical signaling. Interference with the configuration of this protein network can lead to profound effects on neuronal polarity, excitability, cell-to-cell connectivity and brain circuit plasticity. As such, the ability to visualize AIS components with precision provides an invaluable opportunity for parsing out key molecular determinants of neuronal function. Fluorescence-based immunolabeling is a sensitive method for morphological and molecular characterization of fine structures in neurons. Yet, even when combined with confocal microscopy, detection of AIS elements with immunofluorescence has been limited by the loss of antigenicity caused by fixative materials. This technical barrier has posed significant limitations in detecting AIS components alone or in combination with other markers. Here, we designed improved protocols targeted to confocal immunofluorescence detection of the AIS marker fibroblast growth factor 14 (FGF14) in combination with the cytoskeletal-associated protein Ankyrin-G, the scaffolding protein βIV-spectrin, voltage-gated Na+ (Nav) channels (especially the Nav1.6 isoform) and critical cell type-specific neuronal markers such as parvalbumin, calbindin, and NeuN in the mouse brain. Notably, we demonstrate that intracardiac perfusion of animals with a commercially available solution containing 1% formaldehyde and 0.5% methanol, followed by brief fixation with cold acetone is an optimal and sensitive protocol for FGF14 and other AIS marker detection that guarantees excellent tissue integrity. With variations in the procedure, we also significantly improved the detection of Nav1.6, a Nav isoform known for its fixative-sensitivity. Overall, this study provides an ensemble of immunohistochemical recipes that permit excellent staining of otherwise invisible molecules within well-preserved tissue architecture. While improving the specific investigation of AIS physiology and cell biology, our thorough study can also serve as a roadmap for optimizing immunodetection of other fixative-sensitive proteins expanding the repertoire of enabling methods for brain studies.

Apremilast reversed carfilzomib-induced cardiotoxicity through inhibition of oxidative stress, NF-κB and MAPK signaling in rats

Abstract Carfilzomib (CFZ), is a potent, selective second generation proteasome inhibitor, used for the treatment of multiple myeloma. The aim of the present study was to investigate the possible protective effect of apremilast (AP) on the CFZ -induced cardiotoxicity. Rats were randomly divided into four groups: Group 1, served as the control group, received normal saline. Group 2, served as the toxic group, received CFZ (4 mg/kg, intraperitoneally [i.p.]). Groups 3 and 4, served as treatment groups, and received CFZ with concomitant oral administration of AP in doses of 10 and 20 mg/kg/day, respectively. In the present study, administration of CFZ resulted in a significant increase in serum aspartate transaminase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and creatine kinase-MB (CK-MB), which were reversed by treatment with AP. CFZ resulted in a significant increase in heart malondialdehyde (MDA) contents and decrease in cardiac glutathione (GSH) level and catalase (CAT) enzyme activity which were significantly reversed by treatment with AP. Induction of cardiotoxicity by CFZ significantly increased caspase-3 enzyme activity which were reversed by treatment with AP. RT-PCR analysis revealed an increased mRNA expression of NF-κB, ERK and JNK which were reversed by treatment with AP in cardiac tissues. Western blot analysis revealed an increased expression of caspase-3 and NF-κB p65 and a decrease expression of inhibitory kappa B-alpha (Iκbα) with CFZ, which were reversed by treatment with AP. In conclusion, apremilast showed protective effect against CFZ-induced cardiotoxicity.

Fibroblast Growth Factor 14 Modulates the Neurogenesis of Granule Neurons in the Adult Dentate Gyrus

Adult neurogenesis, the production of mature neurons from progenitor cells in the adult mammalian brain, is linked to the etiology of neurodegenerative and psychiatric disorders. However, a thorough understanding of the molecular elements at the base of adult neurogenesis remains elusive. Here, we provide evidence for a previously undescribed function of fibroblast growth factor 14 (FGF14), a brain disease-associated factor that controls neuronal excitability and synaptic plasticity, in regulating adult neurogenesis in the dentate gyrus (DG). We found that FGF14 is dynamically expressed in restricted subtypes of sex determining region Y-box 2 (Sox2)-positive and doublecortin (DCX)-positive neural progenitors in the DG. Bromodeoxyuridine (BrdU) incorporation studies and confocal imaging revealed that genetic deletion of Fgf14 in Fgf14−/− mice leads to a significant change in the proportion of proliferating and immature and mature newly born adult granule cells. This results in an increase in the late immature and early mature population of DCX and calretinin (CR)-positive neurons. Electrophysiological extracellular field recordings showed reduced minimal threshold response and impaired paired-pulse facilitation at the perforant path to DG inputs in Fgf14−/− compared to Fgf14+/+ mice, supporting disrupted synaptic connectivity as a correlative read-out to impaired neurogenesis. These new insights into the biology of FGF14 in neurogenesis shed light into the signaling pathways associated with disrupted functions in complex brain diseases.

Resveratrol attenuates pro-inflammatory cytokines and activation of JAK1-STAT3 in BTBR T + Itpr3 tf /J autistic mice

&NA; Autism is a neurodevelopmental disorder characterized by qualitative impairment in communication, social interaction, and repetitive stereotypic behavior. Resveratrol plays a role in several disorders such as neuroimmune, autoimmune, and allergic disorders. BTBR T+ Itpr3tf/J (BTBR) mice, a model for autism, show several behavioral deficits that are physiological characteristics similar to those observed in patients with autism. Previous studies have shown that JAK‐STAT signaling pathway is associated with many neurodevelopmental disorders. We investigated the possible role of resveratrol on IL‐6+, TNF‐&agr;+, IFN‐&ggr;+, and STAT3+ in CD4+ T spleen cells in BTBR mice as compared to C57BL/6J mice. We also assessed the effect of resveratrol treatment on IL‐6, TNF‐&agr;, IFN‐&ggr;, JAK1, and STAT3 mRNA expression levels in the brain tissue. We further assessed IL‐6, IFN‐&ggr;, TNF‐&agr;, phosphorylated (p) JAK1, and pSTAT3 (Tyr705) protein expression levels in the brain tissue. Resveratrol (20 and 40 mg/kg)‐treated mice had significantly decreased in IL‐6+, TNF‐&agr;+, IFN‐&ggr;+, and STAT3+ in CD4+ spleen cells as compared with BTBR control mice. Resveratrol treatment also decreased IL‐6, TNF‐&agr;, IFN‐&ggr;, JAK1, and STAT3 mRNA expression levels as compared with BTBR control mice in the brain tissue. Moreover, resveratrol treatment resulted in decreased protein expression levels of IL‐6, IFN‐&ggr;, TNF‐&agr;, pJAK1, and pSTAT3 (Tyr705) as compared with BTBR control mice in the brain tissues. Taken together, these results indicate the efficacy of resveratrol in reducing cytokines and JAK‐1/STAT3 signaling in BTBR mice, which is a novel and important finding and might be important for future therapies in neuroimmune dysfunction.

Functional Modulation of Voltage-Gated Sodium Channels by a FGF14-Based Peptidomimetic

Protein-protein interactions (PPI) offer unexploited opportunities for CNS drug discovery and neurochemical probe development. Here, we present ZL181, a novel peptidomimetic targeting the PPI interface of the voltage-gated Na+ channel Nav1.6 and its regulatory protein fibroblast growth factor 14 (FGF14). ZL181 binds to FGF14 and inhibits its interaction with the Nav1.6 channel C-tail. In HEK-Nav1.6 expressing cells, ZL181 acts synergistically with FGF14 to suppress Nav1.6 current density and to slow kinetics of fast inactivation, but antagonizes FGF14 modulation of steady-state inactivation that is regulated by the N-terminal tail of the protein. In medium spiny neurons in the nucleus accumbens, ZL181 suppresses excitability by a mechanism that is dependent upon expression of FGF14 and is consistent with a state-dependent inhibition of FGF14. Overall, ZL181 and derivatives could lay the ground for developing allosteric modulators of Nav channels that are of interest for a broad range of CNS disorders.

Inhibitory Effect of Ginseng on Breast Cancer Cell Line Growth Via Up-Regulation of Cyclin Dependent Kinase Inhibitor, p21 and p53

Objective: Breast cancer is global female health problem worldwide. Most of the currently used agents for breast cancer treatment have toxic side-effects. Ginseng root, an oriental medicine, has many health benefits and may exhibit direct anti-cancer properties. This study was performed to assess the effects of ginseng on breast cancer cell lines. Materials and Methods: Cytotoxicity of ginseng extract was measured by MTT assay after exposure of MDA-MB-231, MCF-10A and MCF-7 breast cancer cells to concentrations of 0.25, 0.5, 1, 1.5, 2 and 2.5 mg/well. Expression levels of p21WAF, p16INK4A, Bcl-2, Bax and P53 genes were analyzed by quantitative real time PCR. Results: The treatment resulted in inhibition of cell proliferation in a dose-and time-dependent manner. p53, p21WAF1and p16INK4A expression levels were up-regulated in ginseng treated MDA-MB-231 and MCF-7 cancer cells compared to untreated controls and in MCF-10A cells. The expression levels of Bcl2 in the MDA-MB-231 and MCF-7 cells were down-regulated. In contrast, that of Bax was significantly up-regulated. Conclusion: The results of this study revealed that ginseng may inhibit breast cancer cell growth by activation of the apoptotic pathway.

Increased oxidative stress in the cerebellum and peripheral immune cells leads to exaggerated autism-like repetitive behavior due to deficiency of antioxidant response in BTBR T + tf/J mice

ABSTRACT Autism is a neurodevelopmental disorder that affects social cognitive abilities resulting in communication or sensory deficits, and stereotyped behaviors in millions of people worldwide. Oxidant‐antioxidant imbalance contributes significantly to the neurobehavioral dysregulations and severity of symptoms in patients with autism, however it has not been explored earlier whether it affects autism‐like behavior directly. Therefore, we investigated oxidant‐antioxidant balance in peripheral immune cells (neutrophils and CD3+ T cells) and cerebellum of BTBR T+tf/J (BTBR) mice which show autism‐like behavior and the social C57BL/6J (C57) mice. Further, we utilized buthionine sulfoximine (BSO), a glutathione depleting agent to assess the impact of oxidant‐antioxidant dysregulation on autism‐like behavior. Our study shows that BTBR mice have increased lipid/protein oxidation products in cerebellum and neutrophils/CD3+ T cells along with increased NADPH oxidase (NOX2) and inducible nitric oxide synthase (iNOS) expression. This was concurrent with lower levels of glutathione and enzymatic antioxidants such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the cerebellum and peripheral immune cells. BSO administration led to further lowering of glutathione with a concurrent upregulation of iNOS, and NOX2 in cerebellum and peripheral immune cells. However, there was deficiency of an adaptive antioxidant response which was associated with exaggerated repetitive behaviors in BTBR mice. On the other hand, C57 mice also had increased oxidative stress after BSO treatment, however there was an enzymatic antioxidant response both in cerebellum and periphery. Overall, this study suggests that BTBR mice have increased oxidative stress with a deficient enzymatic antioxidant response that is associated with autism‐like repetitive behaviors. HIGHLIGHTSBTBR mice have increased peripheral/cerebellar oxidative stress as compared to C57 mice.BTBR mice have deficiency of antioxidant response after induction of oxidative stress.Increased oxidative stress is associated with autism‐like behavior in BTBR mice.

Apremilast prevent doxorubicin-induced apoptosis and inflammation in heart through inhibition of oxidative stress mediated activation of NF-κB signaling pathways

BACKGROUND Doxorubicin is an effective, potent and commonly used anthracycline-related anticancer drug; however, cardiotoxicity compromises its therapeutic potential. Apremilast, a novel phosphodiesterase type 4-inhibitor, reported to have anti-inflammatory effects and modulating many inflammatory mediators. METHODS The present study investigated the influence of apremilast against doxorubicin-induced cardiotoxicity in male Wistar rats. A total, 24 animals were divided into four groups of six animal each. Group 1, served as control and received normal saline. Group 2 animals, received doxorubicin (20 mg kg-1, ip). Group 3 and 4, treatment group, received doxorubicin (20 mg kg-1, ip) with the same schedule as group-2, plus apremilast (10 and 20 mg kg-1 day-1, po) respectively. Oxidative stress, caspase-3 enzyme activity, gene expression and protein expression were tested. RESULTS The results of the present study demonstrated that administration of apremilast reversed doxorubicin-induced cardiotoxicity. CONCLUSION These findings suggested that apremilast can attenuate doxorubicin-induced cardiotoxicity via inhibition of oxidative stress mediated activation of nuclear factor-kappa B signaling pathways.BACKGROUND Doxorubicin is an effective, potent and commonly used anthracycline-related anticancer drug; however, cardiotoxicity compromises its therapeutic potential. Apremilast, a novel phosphodiesterase type 4-inhibitor, reported to have anti-inflammatory effects and modulating many inflammatory mediators. METHODS The present study investigated the influence of apremilast against doxorubicin-induced cardiotoxicity in male Wistar rats. A total, 24 animals were divided into four groups of six animal each. Group 1, served as control and received normal saline. Group 2 animals, received doxorubicin (20mgkg-1, ip). Group 3 and 4, treatment group, received doxorubicin (20mgkg-1, ip) with the same schedule as group-2, plus apremilast (10 and 20mgkg-1day-1, po) respectively. Oxidative stress, caspase-3 enzyme activity, gene expression and protein expression were tested. RESULTS The results of the present study demonstrated that administration of apremilast reversed doxorubicin-induced cardiotoxicity. CONCLUSION These findings suggested that apremilast can attenuate doxorubicin-induced cardiotoxicity via inhibition of oxidative stress mediated activation of nuclear factor-kappa B signaling pathways.