6-7-dihydroxyflavone and Cognition-Disorders

Brain-derived neurotrophic factor (BDNF) and its high-affinity receptor, tropomyosin receptor kinase B (TrkB) signaling plays a key role in the brain neurodevelopment. The exposure of pregnant mice to polyinosinic-polycytidylic acid [poly(I:C)] causes cognitive deficits in adult offspring. Supplementation with a TrkB agonist, 7,8-dihydroxyflavone, in poly(I:C)-treated pregnant mice from pregnancy to weaning could prevent the onset of cognitive deficits and reduced BDNF-TrkB signaling in the prefrontal cortex of their adult offspring. These findings suggest that supplementation with a TrkB agonist in pregnant women with an ultra-high risk of psychosis may reduce the development of psychosis in their offspring.

Topics: Analysis of Variance; Animals; Brain; Brain-Derived Neurotrophic Factor; Cognition Disorders; Disease Models, Animal; Drug Administration Schedule; Female; Flavones; Interferon Inducers; Locomotion; Male; Mice; Poly I-C; Pregnancy; Prenatal Exposure Delayed Effects; Receptor, trkB; Recognition, Psychology; Signal Transduction

Brain radiotherapy is frequently used successfully to treat brain tumors. However, radiotherapy is often associated with declines in short-term and long-term memory, learning ability, and verbal fluency. We previously identified a downregulation of the brain-derived neurotrophic factor (BDNF) following cranial irradiation in experimental animals. In the present study, we investigated whether targeting the BDNF high affinity receptor, tropomysin receptor kinase B (TrkB), could mitigate radiation-induced cognitive deficits. After irradiation, chronic treatment with a small molecule TrkB agonist, 7,8-dihydroxyflavone (DHF) in mice led to enhanced activation of TrkB and its downstream targets ERK and AKT, both important factors in neuronal development. DHF treatment significantly restored spatial, contextual, and working memory, and the positive effects persisted for at least 3months after completion of the treatment. Consistent with preservation of cognitive functions, chronic DHF treatment mitigated radiation-induced suppression of hippocampal neurogenesis. Spine density and major components of the excitatory synapses, including glutamate receptors and postsynaptic density protein 95 (PSD-95), were also maintained at normal levels by DHF treatment after irradiation. Taken together, our results show that chronic treatment with DHF after irradiation significantly mitigates radiation-induced cognitive defects. This is achieved most likely by preservation of hippocampal neurogenesis and synaptic plasticity.

Topics: Animals; Brain; Brain-Derived Neurotrophic Factor; Cognition Disorders; Down-Regulation; Flavones; Hippocampus; Male; Memory, Short-Term; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinase Kinases; Neurogenesis; Neuronal Plasticity; Oncogene Protein v-akt; Radiation Injuries; Receptor, trkB; Receptors, Glutamate; Spatial Memory; Synapses

Fragile X syndrome (FXS) is characterized by immature dendritic spine architectures and cognitive impairment. 7, 8-Dihydroxyflavone (7, 8-DHF) has recently been identified as a high affinity tropomyosin receptor kinase B (TrkB) agonist. The purpose of this paper was to examine the utility of 7, 8-DHF as an effective pharmacotherapeutic agent that targets dendritic pathology and cognitive impairments in FXS mutant. We synthesized pharmacologic, behavioral, and biochemical approaches to examine the effects of 7, 8-DHF on spatial and fear memory functions, and morphological spine abnormalities in fragile X mental retardation 1 (Fmr1) gene knock-out mice. The study found that 4 weeks of treatment with 7, 8-DHF improved spatial and fear memory, and ameliorated morphological spine abnormalities including the number and elongation of spines in the hippocampus and amygdala. Further mechanism analysis revealed that 7, 8-DHF enhanced the expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) GluA1 receptor, but reduced the normal levels of GluA2 at the synapses in Fmr1. Potentially related to drug-induced changes in AMPA receptor subunits, 7, 8-DHF at the synapses led to phosphorylation of specific serine sites on subunits Ser818 and Ser813 of GluA1, and Ser880 of GluA2, as well as phosphorylation of TrkB, calcium/calmodulin-dependent protein kinase II, and protein kinase C. However, 7, 8-DHF neither affected behavioral performance nor increased TrkB phosphorylation in WT mice, which suggested that it had FXS-specific correcting effect. Altogether, these results demonstrated that 7, 8-DHF improved learning and memory, and reduced abnormalities in spine morphology, thus providing a potential pharmacotherapeutic strategy for FXS.

Topics: Animals; Cognition Disorders; Dendritic Spines; Disease Models, Animal; Flavones; Fragile X Syndrome; Gene Expression Regulation; Male; Mice; Mice, Knockout; Receptors, AMPA; Synapses

Traumatic brain injury (TBI) is followed by a state of metabolic dysfunction, affecting the ability of neurons to use energy and support brain plasticity; there is no effective therapy to counteract the TBI pathology. Brain-derived neurotrophic factor (BDNF) has an exceptional capacity to support metabolism and plasticity, which highly contrasts with its poor pharmacological profile. We evaluated the action of a flavonoid derivative 7,8-dihydroxyflavone (7,8-DHF), a BDNF receptor (TrkB) agonist with the pharmacological profile congruent for potential human therapies. Treatment with 7,8-DHF (5mg/kg, ip, daily for 7 days) was effective to ameliorate the effects of TBI on plasticity markers (CREB phosphorylation, GAP-43 and syntaxin-3 levels) and memory function in Barnes maze test. Treatment with 7,8-DHF restored the decrease in protein and phenotypic expression of TrkB phosphorylation after TBI. In turn, intrahippocampal injections of K252a, a TrkB antagonist, counteracted the 7,8-DHF induced TrkB signaling activation and memory improvement in TBI, suggesting the pivotal role of TrkB signaling in cognitive performance after brain injury. A potential action of 7,8-DHF on cell energy homeostasis was corroborated by the normalization in levels of PGC-1α, TFAM, COII, AMPK and SIRT1 in animals subjected to TBI. Results suggest a potential mechanism by which 7,8-DHF counteracts TBI pathology via activation of the TrkB receptor and engaging the interplay between cell energy management and synaptic plasticity. Since metabolic dysfunction is an important risk factor for the development of neurological and psychiatric disorders, these results set a precedent for the therapeutic use of 7,8-DHF in a larger context.

Topics: Animals; Brain Injuries; Carbazoles; Cognition Disorders; Cyclic AMP Response Element-Binding Protein; Energy Metabolism; Flavones; GAP-43 Protein; Immunoblotting; Indole Alkaloids; Male; Maze Learning; Memory; Microscopy, Fluorescence; Mitochondria; Phosphorylation; Qa-SNARE Proteins; Rats, Sprague-Dawley; Receptor, trkB; Signal Transduction

Accumulation of stressful events can render individuals susceptible to develop epilepsy and comorbidities. Whether such vulnerability can be predicted and reversed is not known. Here we show that social defeat, although not producing depression by itself, produced in 50% of rats reduced threshold for status epilepticus (SE), accelerated epileptogenesis, and once epilepsy was induced, depression-like profile and cognitive deficits. Low serum brain-derived neurotrophic factor (BDNF) levels measured before SE identified this vulnerable population. Treatment with a BDNF analog before SE prevented the occurrence of comorbidities. Thus, vulnerability to comorbidities after epilepsy onset due to unresolved past stressful events may be predicted and reversed.

Topics: Allostasis; Animals; Brain-Derived Neurotrophic Factor; Cognition Disorders; Depression; Disease Models, Animal; Epilepsy; Excitatory Amino Acid Agonists; Flavones; Hypothalamo-Hypophyseal System; Kainic Acid; Male; Pituitary-Adrenal System; Rats; Rats, Sprague-Dawley; Social Environment; Status Epilepticus; Stress, Psychological

Cognitive deficits are the core symptoms of schizophrenia and major contributors to disability in schizophrenic patients, but effective treatments are still lacking. Previous studies have demonstrated that impaired BDNF/TrkB signaling is associated with the cognitive impairments of schizophrenia. 7,8-Dihydroxyflavone (7,8-DHF) has recently been identified as a specific TrkB agonist that crosses the blood-brain barrier after oral or intraperitoneal administration. The present study aimed to assess the effect of 7,8-DHF on the cognitive and synaptic impairments of schizophrenia. A brief disruption of NMDA receptors with MK-801 during early development serves as an animal model for cognitive deficits of schizophrenia. We found that MK-801-treated rats showed significant deficits in working learning ability and hippocampal synaptic plasticity, as well as reduction of BDNF, TrkB, and phosphorylated TrkB in the hippocampus. After intraperitoneal administration with 7,8-DHF (5 mg/kg) once daily for a consecutive 14days, we found that chronic 7,8-DHF treatment significantly enhanced the activation of phosphorylated TrkB at the Y515 and Y816 sites, increased the phosphorylation levels of TrkB downstream signal cascades including ERK1/2, CaMKII, CREB and GluR1, and promoted hippocampal synaptic plasticity, which in turn rescued performance in spatial working learning. Our results thus demonstrate that activation of TrkB signaling can reverse the cognitive deficits of schizophrenia and strongly suggest a potential usefulness for 7,8-DHF or a TrkB agonist in treating schizophrenia-related cognitive impairments.

Topics: Animals; Cognition Disorders; Disease Models, Animal; Dizocilpine Maleate; Flavones; Hippocampus; Male; Neuronal Plasticity; Organ Culture Techniques; Random Allocation; Rats; Rats, Sprague-Dawley; Receptor, trkB; Schizophrenia

7,8-dihydroxyflavone (7,8-DHF) has recently been identified as a potential TrkB agonist that crosses the blood-brain barrier after i.p. administration. We previously demonstrated that 7,8-DHF in vitro rescues long-term synaptic plasticity in the hippocampus of aged rats. This study assessed the rescue effect of 7,8-DHF in vivo on aging-related cognitive impairment in rats, and further determined whether the effect of 7,8-DHF is age dependent. Aged rats at 22 and 30 months of age were pretested for spatial memory in Morris water maze. The aged-impaired rats were retested twice during 7,8-DHF or vehicle treatment, which started 3 weeks after the completion of the pretest. In the 22-month-old rats, daily i.p. administration of 7,8-DHF for 2 weeks improved spatial memory. The improvement in behavioral tests was associated with increases in synapse formation and facilitation of synaptic plasticity in the hippocampus, as well as the activation of several proteins crucial to synaptic plasticity and memory. A more extended treatment paradigm with 7,8-DHF was required to achieve a significant memory improvement in the severely impaired 30-month-old rats. Moreover, 7,8-DHF moderately facilitated the synaptic plasticity, modified the density but not number of spines in the hippocampus of the oldest rats. Taken together, our results suggest that 7,8-DHF can act in vivo to counteract aging-induced declines in spatial memory and synaptic plasticity and morphological changes of hippocampal neurons. The effect of 7,8-DHF is more pronounced in relatively younger impaired rats than in those of more advanced age. These findings demonstrate the reversal of age-dependent memory impairment by in vivo 7,8-DHF application and support the benefit of early treatment for cognitive aging.

Topics: Aging; Animals; Blotting, Western; Cognition Disorders; Dendritic Spines; Electric Stimulation; Electrophysiological Phenomena; Excitatory Postsynaptic Potentials; Flavones; Hippocampus; Injections, Intraperitoneal; Maze Learning; Memory; Nerve Tissue Proteins; Neuronal Plasticity; Rats; Receptor, trkB