The flavonoid 7,8-DHF fosters prenatal brain proliferation potency in a mouse model of Down syndrome

Effect of Blackberry Juice Consumption by Pregnant Rats on Brain Length and Cell Density of Dentate Gyrus in Male Wistar Pups

The aim of this work was to evaluate the effect of blackberry juice consumption during pregnancy on the length of the brain, as well as on the cell density of the dentate gyrus in Wistar rat pups. Pregnant rats were divided into three groups: control (C), fed with standard diet and water ad libitum; BJ1, which received blackberry juice containing polyphenols (7.8 mg/kg) and anthocyanins (1.9 mg/kg); and BJ2, receiving blackberry juice containing polyphenols (9.3 mg/kg) and anthocyanins (3.54 mg/kg). On postnatal day 0, pups per litter, body weight, and length were measured, and cells in the dentate gyrus of male pups were quantified. Maternal body weight and pups per litter were statistically equal across experimental groups during pregnancy. Pups in BJ1 and BJ2 groups showed an increase in body weight (20%) and length (5%) when comparing to controls. An increase in brain length was observed in BJ2 group (8%) as compared to the control. A significant increase in the number of cells/mm2 was observed in the dentate gyrus of the offspring in BJ1 (21.8%) and BJ2 (23.7%) groups when compared to the control group. Given the above, blackberry juice may be considered a potential functional food during pregnancy, while further research on prenatal and postnatal development must be done.

REST Targets JAK-STAT and HIF-1 Signaling Pathways in Human Down Syndrome Brain and Neural Cells

Down syndrome (DS) is the most frequently diagnosed chromosomal disorder of chromosome 21 (HSA21) aneuploidy, characterized by intellectual disability and reduced lifespan. The transcription repressor, Repressor Element-1 Silencing Transcription factor (REST), which acts as an epigenetic regulator, is a crucial regulator of neuronal and glial gene expression. In this study, we identified and investigated the role of REST-target genes in human brain tissues, cerebral organoids, and neural cells in Down syndrome. Gene expression datasets generated from healthy controls and DS samples of human brain tissues, cerebral organoids, NPC, neurons, and astrocytes were retrieved from the Gene Ontology (GEO) and Sequence Read Archive (SRA) databases. Differential expression analysis was performed on all datasets to produce differential expression genes (DEGs) between DS and control groups. REST-targeted DEGs were subjected to functional ontologies, pathways, and network analyses. We found that REST-targeted DEGs in DS were enriched for the JAK-STAT and HIF-1 signaling pathways across multiple distinct brain regions, ages, and neural cell types. We also identified REST-targeted DEGs involved in nervous system development, cell differentiation, fatty acid metabolism and inflammation in the DS brain. Based on the findings, we propose REST as the critical regulator and a promising therapeutic target to modulate homeostatic gene expression in the DS brain.

Therapeutics for mitochondrial dysfunction-linked diseases in Down syndrome

Genome-wide deregulation contributes to mitochondrial dysfunction and impairment in oxidative phosphorylation (OXPHOS) mechanism resulting in oxidative stress, increased production of reactive oxygen species (ROS) and cell death in individuals with Down syndrome (DS). The cells, which require more energy, such as muscles, brain and heart are greatly affected. Impairment in mitochondrial network has a direct link with patho-mechanism at cellular and systemic levels at the backdrop of generalized metabolic perturbations in individuals with DS. Myriads of clinico-phenotypic features, including intellectual disability, early aging and neurodegeneration, and Alzheimer disease (AD)-related dementia are inevitable in DS-population where mitochondrial dysfunctions play the central role. Collectively, the mitochondrial abnormalities and altered energy metabolism perturbs several signaling pathways, particularly related to neurogenesis, which are directly associated with cognitive development and early onset of AD in individuals with DS. Therefore, therapeutic challenges for amelioration of the mitochondrial defects were perceived to improve the quality of life of the DS population. A number of pharmacologically active natural compounds such as polyphenols, antioxidants and flavonoids have shown convincing outcome for reversal of the dysfunctional mitochondrial network and oxidative metabolism, and improvement in intellectual skill in mouse models of DS and humans with DS.

7,8-Dihydroxyflavone attenuates the virulence of Staphylococcus aureus by inhibiting alpha-hemolysin

Staphylococcus aureus (S. aureus), a Gram-positive bacteria, is an incurable cause of hospital and community-acquired infections. Inhibition bacterial virulence is a viable strategy against S. aureus infections based on the multiple virulence factors secreted by S. aureus. Alpha-hemolysin (Hla) plays a crucial role in bacteria virulence without affecting bacterial viability. Here, we identified that 7,8-Dihydroxyflavone (7,8-DHF), a natural compound, was able to decrease the expression of and did not affect the in vitro growth of S. aureus USA300 at a concentration of 32 μg/mL. It was verified by western blot and RT-qPCR that the natural compound could inhibit the transcription and translation of Hla. Further mechanism studies revealed that 7,8-DHF has a negative effect on transcriptional regulator agrA and RNAIII, preventing the upregulation of virulence gene. Cytotoxicity assays showed that 7,8-DHF did not produce significant cytotoxicity to A549 cells. Animal experiments showed that the combination of 7,8-DHF and vancomycin had a more significant therapeutic effect on S. aureus infection, reflecting the synergistic effect of 7,8-DHF with antibiotics. In conclusion, 7,8-DHF was able to target Hla to protect host cells from hemolysis while limiting the development of bacterial resistance.

An Shen Ding Zhi Ling Ameliorates the Symptoms of Attention Deficit Hyperactivity Disorder via Modulating Brain-Derived Neurotrophic Factor-Related Signaling Pathways

Attention deficit hyperactivity disorder (ADHD) is a common childhood neurodevelopmental disorder. It may impact the cognitive and social functions throughout childhood and determine adult outcomes. Dopamine (DA) deficiency theory is the pathogenesis of ADHD that is recognized by most international literature. Existing studies have shown that DA deficiency is caused by the abnormal function of the DA transporter and an imbalance in the DA receptor functionality. Recent clinical and experimental studies have found that the brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) signaling pathway acts a pivotal part in DA vesicle circulation and ADHD pathogenesis. An Shen Ding Zhi Ling (ASDZL) is a traditional Chinese medicine (TCM) prescription, which was widely prescribed to treat ADHD in Jiangsu, China, but its therapeutic mechanism is unclear. Therefore, we constructed a spontaneously hypertensive rat (SHR) model to explain its mechanism. SHRs were randomly assigned to four groups: SHR model group (vehicle), methylphenidate hydrochloride group (MPH), ASDZL group, and 7,8-dihydroxyflavone group (7,8-DHF). At the same time, the above groups were given continuous medication for four weeks. The results show that ASDZL, MPH, and 7,8-DHF group could significantly improve the spatial memory of SHRs in the Morris water maze tests. ASDZL increased the levels of BDNF, TrkB, p75 neurotrophin receptor (p75), C-Jun N-terminal kinases 1 (JNK1), and nuclear factor kappa B (NF-κB) in the prefrontal cortex (PFC) and hippocampus synaptosome of SHRs. The results of this study suggest that ASDZL can relieve the symptoms of ADHD in SHRs by regulating the balance between the BDNF/TrkB signaling pathway (promoting vesicle circulation) and the BDNF/P75/JNK1/NF-κB signaling pathway (inhibiting vesicle circulation) within the PFC and hippocampus synaptosome to increase the DA concentration in the synaptic cleft. The BDNF/TrkB signal pathway within the PFC and hippocampus synaptosome was activated by 7,8-DHF to increase DA concentration in the synaptic cleft. Whether 7,8-DHF can activate or inhibit the BDNF/P75 signaling pathway remains unclear.

7,8-Dihydroxyflavone and Neuropsychiatric Disorders: A Translational Perspective from the Mechanism to Drug Development

7,8-Dihydroxyflavone (7,8-DHF) is a kind of natural flavonoid with the potential to cross the blood-brain barrier. 7,8-DHF effectively mimics the effect of brain-derived neurotrophic factor (BDNF) in the brain to selectively activate tyrosine kinase receptor B (TrkB) and downstream signaling pathways, thus playing a neuroprotective role. The preclinical effects of 7,8-DHF have been widely investigated in neuropsychiatric disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), depression, and memory impairment. Besides the effect on TrkB, 7,8-DHF could also function through fighting against oxidative stress, cooperating with estrogen receptors, or regulating intestinal flora. This review focuses on the recent experimental studies on depression, neurodegenerative diseases, and learning and memory functions. Additionally, the structural modification and preparation of 7,8-DHF were also concluded and proposed, hoping to provide a reference for the follow-up research and clinical drug development of 7,8-DHF in the field of neuropsychiatric disorders.

The Challenging Pathway of Treatment for Neurogenesis Impairment in Down Syndrome: Achievements and Perspectives

Down syndrome (DS), also known as trisomy 21, is a genetic disorder caused by triplication of Chromosome 21. Gene triplication may compromise different body functions but invariably impairs intellectual abilities starting from infancy. Moreover, after the fourth decade of life people with DS are likely to develop Alzheimer’s disease. Neurogenesis impairment during fetal life stages and dendritic pathology emerging in early infancy are thought to be key determinants of alterations in brain functioning in DS. Although the progressive improvement in medical care has led to a notable increase in life expectancy for people with DS, there are currently no treatments for intellectual disability. Increasing evidence in mouse models of DS reveals that pharmacological interventions in the embryonic and neonatal periods may greatly benefit brain development and cognitive performance. The most striking results have been obtained with pharmacotherapies during embryonic life stages, indicating that it is possible to pharmacologically rescue the severe neurodevelopmental defects linked to the trisomic condition. These findings provide hope that similar benefits may be possible for people with DS. This review summarizes current knowledge regarding (i) the scope and timeline of neurogenesis (and dendritic) alterations in DS, in order to delineate suitable windows for treatment; (ii) the role of triplicated genes that are most likely to be the key determinants of these alterations, in order to highlight possible therapeutic targets; and (iii) prenatal and neonatal treatments that have proved to be effective in mouse models, in order to rationalize the choice of treatment for human application. Based on this body of evidence we will discuss prospects and challenges for fetal therapy in individuals with DS as a potential means of drastically counteracting the deleterious effects of gene triplication.

Prenatal and Postnatal Pharmacotherapy in Down Syndrome: The Search to Prevent or Ameliorate Neurodevelopmental and Neurodegenerative Disorders

Those with Down syndrome (DS)-trisomy for chromosome 21-are routinely impacted by cognitive dysfunction and behavioral challenges in children and adults and Alzheimer's disease in older adults. No proven treatments specifically address these cognitive or behavioral changes. However, advances in the establishment of rodent models and human cell models promise to support development of such treatments. A research agenda that emphasizes the identification of overexpressed genes that contribute demonstrably to abnormalities in cognition and behavior in model systems constitutes a rational next step. Normalizing expression of such genes may usher in an era of successful treatments applicable across the life span for those with DS.

Impaired Brain Mitochondrial Bioenergetics in the Ts65Dn Mouse Model of Down Syndrome Is Restored by Neonatal Treatment with the Polyphenol 7,8-Dihydroxyflavone

Down syndrome (DS), a major genetic cause of intellectual disability, is characterized by numerous neurodevelopmental defects. Previous in vitro studies highlighted a relationship between bioenergetic dysfunction and reduced neurogenesis in progenitor cells from the Ts65Dn mouse model of DS, suggesting a critical role of mitochondrial dysfunction in neurodevelopmental alterations in DS. Recent in vivo studies in Ts65Dn mice showed that neonatal supplementation (Days P3–P15) with the polyphenol 7,8-dihydroxyflavone (7,8-DHF) fully restored hippocampal neurogenesis. The current study was aimed to establish whether brain mitochondrial bioenergetic defects are already present in Ts65Dn pups and whether early treatment with 7,8-DHF positively impacts on mitochondrial function. In the brain and cerebellum of P3 and P15 Ts65Dn pups we found a strong impairment in the oxidative phosphorylation apparatus, resulting in a deficit in mitochondrial ATP production and ATP content. Administration of 7,8-DHF (dose: 5 mg/kg/day) during Days P3–P15 fully restored bioenergetic dysfunction in Ts65Dn mice, reduced the levels of oxygen radicals and reinstated the hippocampal levels of PGC-1α. No pharmacotherapy is available for DS. From current findings, 7,8-DHF emerges as a treatment with a good translational potential for improving mitochondrial bioenergetics and, thus, mitochondria-linked neurodevelopmental alterations in DS.