Experimental and computational modeling of interaction of kolaviron-kolaflavanone with aldehyde dehydrogenase

Aldehyde dehydrogenases (ALDHs) are a diverse family of enzymes that catalyze the NAD(P)⁺-dependent detoxification of toxic aldehyde compounds. ALDHs are also involved in non-enzymatic ligand binding to endobiotics and xenobiotics. Here, the enzyme crucial non-canonical and non-catalytic interaction with kolaflavanone, a component of kolaviron, and a major bioflavonoid isolated from Garcinia kola (Bitter kola) was characterized by various spectroscopic and in silico approaches under simulated physiological condition. Kolaflavanone quenched the intrinsic fluorescence of ALDH in a concentration dependent manner with an effective quenching constant (K_sv) of 1.14 × 10³ L.mol⁻¹ at 25 °C. The enzyme has one binding site for kolaflavanone with a binding constant (K_a) of 2.57 × 10⁴ L.mol⁻¹ and effective Forster resonance energy transfer (FRET) of 4.87 nm. The bonding process was enthalpically driven. The reaction was not spontaneous and was predominantly characterized by Van der Waals forces and hydrogen bond. The flavonoid bonding slightly perturbed the secondary and tertiary structures of ALDH that was ‘tryptophan-gated’. The interaction was regulated by both diffusion and ionic strength. Molecular docking showed the binding of kolaflavanone was at the active site of ALDH and the participation of some amino acid residues in the complex formation with −9.6 kcal mol⁻¹ binding energy. The profiles of atomic fluctuations indicated the rigidity of the ligand-binding site during the simulation. With these, ALDH as a subtle nano-particle determinant of kolaviron bioavailability and efficacy is hereby proposed.     

自闭症患儿肠道菌群变化及其与自闭症分级的关系

目的分析自闭症患儿肠道菌群的变化及其与疾病发展的关系。方法选择2018年6月至2019年6月我院收治的134例自闭症患儿为观察组,根据美国精神疾病分类与诊断标准(第5版)将自闭症患儿按病情严重程度分为一级组(51例)、二级组(47例)、三级组(36例)。选择同期于我院进行体检的50例健康儿童为对照组。比较各组儿童胃肠道症状和肠道菌群分布情况,采用Spearman相关性分析自闭症患儿病情分级与肠道菌群关系。结果对照组、一级组、二级组、三级组儿童胃肠道症状发生率依次上升(均P0.05)。对照组、一级组、二级组、三级组儿童肠道双歧杆菌数量依次下降,而梭状芽孢杆菌、大肠埃希菌、拟杆菌、志贺菌数量依次上升(均P0.05)。自闭症患儿肠道双歧杆菌数量与自闭症分级呈负相关(r=-0.746,P0.001),梭状芽孢杆菌、大肠埃希菌、拟杆菌、志贺菌数量与自闭症分级呈正相关(r=0.811、0.659、0.744、0.760,均P0.001)。结论自闭症患儿胃肠道疾病发生率较高,自闭症分级与肠道菌群分布情况具有显著相关性。     

Dystroglycan Binding to α-Neurexin Competes with Neurexophilin-1 and Neuroligin in the Brain

α-Neurexins (α-Nrxn) are mostly presynaptic cell surface molecules essential for neurotransmission that are linked to neuro-developmental disorders as autism or schizophrenia. Several interaction partners of α-Nrxn are identified that depend on alternative splicing, including neuroligins (Nlgn) and dystroglycan (αDAG). The trans-synaptic complex with Nlgn1 was extensively characterized and shown to partially mediate α-Nrxn function. However, the interactions of α-Nrxn with αDAG, neurexophilins (Nxph1) and Nlgn2, ligands that occur specifically at inhibitory synapses, are incompletely understood. Using site-directed mutagenesis, we demonstrate the exact binding epitopes of αDAG and Nxph1 on Nrxn1α and show that their binding is mutually exclusive. Identification of an unusual cysteine bridge pattern and complex type glycans in Nxph1 ensure binding to the second laminin/neurexin/sex hormone binding (LNS2) domain of Nrxn1α, but this association does not interfere with Nlgn binding at LNS6. αDAG, in contrast, interacts with both LNS2 and LNS6 domains without inserts in splice sites SS#2 or SS#4 mostly via LARGE (like-acetylglucosaminyltransferase)-dependent glycans attached to the mucin region. Unexpectedly, binding of αDAG at LNS2 prevents interaction of Nlgn at LNS6 with or without splice insert in SS#4, presumably by sterically hindering each other in the u-form conformation of α-Nrxn. Thus, expression of αDAG and Nxph1 together with alternative splicing in Nrxn1α may prevent or facilitate formation of distinct trans-synaptic Nrxn·Nlgn complexes, revealing an unanticipated way to contribute to the identity of synaptic subpopulations.     

Genetic and epigenetic factors associated with depression: An updated overview

Depression is a complex psychiatric disturbance involving many environmental, genetic, and epigenetic factors. Until now, genetic, and non-genetic studies are still on the way to understanding the complex mechanism of this disease, and there are still many questions that have not yet been answered. Depression includes a large spectrum of heterogeneous symptoms correlated to the deficit of a range of psychological, cognitive, and emotional processes, and it affects various age groups. It is classified into several types according to the severity of symptoms, time of occurrence, and time. Following the World Health Organization (WHO), depression attacks near 350 million persons globally. Several factors overlap in causing depression, including genetic and epigenetic factors, environmental conditions, various stresses, lack of some nutrients to which people are exposed, and excessive stress and abuse in childhood. This study included conducting surveys on depression and new treatment trends based on epigenetic factors associated with the occurrence of the disease. Epigenetic factors provide a completely novel dimension to therapeutic approaches as most diseases are not monogenic, and it is likely that the environment has a significant contribution. Epigenetic inheritance is included in many mental and psychiatric disorders such as depression. In general, epigenetic modifications could be summarized in 3 major points: DNA methylation, histone modification, and non-mediated regulation of RNA (ncRNA). This study also describes some genes associated with one of the depressive disorders using bioinformatics tools and gene bank and had the genes: SLC6A4, COMT, TPH2, FKBP5, MDD1, HTR2A, and MDD2. As in this study, the awareness of Saudi society about depression and its genetic and non-genetic causes was estimated. The results showed that an encouraging percentage of more than half of the research sample possessed correct information about this disorder.     

Detection of antinuclear and antilaminin antibodies in autistic children who received thimerosal-containing vaccines

Autism, a neurodevelopmental disorder, may involve autoimmune pathogenesis. Since mercury is potentially a risk factor for autoimmunity, we conducted a study of mercury-induced antinuclear and antilaminin antibodies in autistic and normal children who had been pre-administered with thimerosal-containing vaccines. Laboratory analysis by different immunoassays showed that the serum level of these two autoimmune markers did not significantly differ between autistic and normal children. This finding suggests that the mercury as in thimerosal-containing vaccines is likely not related to autoimmune phenomenon in autism.     

Implementation of subcellular water mapping by electron energy loss spectroscopy in a medium-voltage scanning transmission electron microscope

The water concentration in biological cells plays a predominant role in cellular life. Using electron energy loss spectroscopy, the feasibility to measure the water content in cells has already been demonstrated. In this paper, we present an upgrade of water measurement in hydrated cryosections by spectrum imaging mode in a medium-voltage scanning transmission electron microscope. The electron energy loss spectra are recorded in spectrum imaging mode in a 2ⁿ×2ⁿ pixels array. Each spectrum is processed in order to determine the water mass content in the corresponding pixel. Then a parametric image is obtained in which grey levels are related to water concentration. In this image, it is possible to recognize the different subcellular compartments. By averaging the water concentration over the relevant pixels, we can determine the water mass content in the concerned subcellular compartment. As an example, we present water mass content measurement at subcellular level in rat hepatocytes.     

The Arg473Cys-neuroligin-1 mutation modulates NMDA mediated synaptic transmission and receptor distribution in hippocampal neurons

Synapses mediate communication between neurons, thus playing a fundamental role in information processing in the CNS. Neuroligins form a family of heterophilic synaptic cell adhesion molecules, and neuroligin 1 (NL1) has been shown to be involved in the formation of excitatory synapses and have been suggested to associate indirectly with NMDA receptors by common binding to PSD95. A mutation in neuroligin 3 (Arg451Cys-NL3, human sequence numbering) identified in autistic patients is associated with altered spine density and has reduced binding capacity for its presynaptic partner beta-neurexin. Here, we investigated the role of NL1 and the homologous NL1 mutation Arg473Cys-NL1 (R473C-NL1) in excitatory synaptic transmission and NMDA receptor distribution. We demonstrate that R473C-NL1, when expressed in cultured hippocampal neurons, can induce a dramatic increase in NMDA current amplitude and that this change is accompanied by NMDA receptor clustering in the postsynaptic cell.     

Dog as a model in studies on human hereditary diseases and their gene therapy

During the last 15 years spectacular progress has been achieved in knowledge on the dog genome organization and the molecular background of hereditary diseases in this species. A majority of canine genetic diseases have their counterparts in humans and thus dogs are considered as a very important large animal model in human biomedicine. Among canine monogenic diseases with known causative gene mutations there are two large groups classified as retinal dystrophies and lysosomal storage diseases. Specific types of these diseases are usually diagnosed in a single or several breeds. A well known disorder, restricted to a single breed, is congenital stationary night blindness described in Briards. This disease is a counterpart of Leber amaurosis in children. On the other hand, one of the most common monogenic human diseases (Duchenne muscular dystrophy), has its canine counterparts in several breeds (e.g., the Golden retriever, Beagle and German short-haired pointer). For some of the canine diseases gene therapy strategy was successfully applied, e.g., for congenital stationary night blindness, rod-cone dystrophy and muccopolysaccharydoses type I, IIIB and VII. Since phenotypic variability between the breeds is exceptionally high, the dog is an interesting model to study the molecular background of congenital malformations (e.g., dwarfism and osteoporosis imperfecta). Also disorders of sexual development (DSD), especially testicular or ovotesticular DSD (78,XX; SRY-negative), which is widely distributed across dozens of breeds, are of particular interest. Studies on the genetic background of canine cancers, a major health problem in this species, are also quite advanced. On the other hand, genetic studies on canine counterparts of major human complex diseases (e.g., obesity, the metabolic syndrome and diabetes mellitus) are still in their infancy.     

Modulation of induced frontocentral theta (Fm-θ) event-related (de-)synchronisation dynamics following mindfulness-based cognitive therapy in Major Depressive Disorder

Depressive severity has been associated with attenuated neocortical frontal midline theta (Fm-θ) power/evoked activity. Mindfulness-Based Cognitive Therapy (MBCT) has shown to be a successful novel intervention for Major Depressive Disorder (MDD), albeit precise working mechanisms remain elusive. We examined the hypothesis that MBCT would have modulating effects upon evoked Fm-θ power, in addition to investigating possible mediation of induced event-related de/synchronisation (ERD/ERS) dynamics. Fifty one patients with a primary diagnosis of MDD (26 exposed to MBCT vs. 25 wait-list/WL controls) undertook a Go/NoGo task consisting of positive, negative and neutral words, further stratified into abstract versus trait adjective matrices. Depressive symptom severity and rumination were also examined. A pattern of enhanced induced Fm-θ synchronisation during the latter 400–800 ms temporal-window pre-to-post MBCT was observed; the contrary in the WL. Modulated ERD/ERS dynamics correlated to amelioration in depressive and rumination symptoms in the MBCT group. We propose the primary action pathway alluded to a neural disengagement mechanism enacting upon tonic neuronal assemblies implicated in emotional and self-related processing. Due to the complexity and presently undiscovered complete unified scientific understanding of neuro-oscillatory-dynamics, and associated clinical interplays; we hypothesise that the electro-cortical and connected clinical working pathways of MBCT in depression are multi-levelled constituting nonlinear and interdependent mechanisms, represented by mediated EEG synchronisation dynamics.     

自闭症儿童口腔正畸治疗中系统性心理预防与干预的作用

目的:评估系统性心理预防及干预在自闭症儿童口腔疾病治疗中的作用。方法:将在我医院进行正畸治疗的40例12~16岁自闭症患者按着随机分配分为对照组与实验组,每组各20例。在正畸治疗过程中,对照组实施常规心理行为预防及干预,包括:治疗前的基础准备、治疗过程中注意事项、治疗后康复方案及辅助治疗等。而对于实验组,除了实施常规的行为预防及干预外,还进行系统性心理行为预防及干预,包括:语言疏导、健康教育、辅助矫正、生命体征监测、肢体语言演示等。结果:实验组和控制组的孩子们能够完成正畸治疗,自闭症儿童治疗配合的的程度,听话依从性,显著高于对照组(P0.01),两组之间蛀牙数和牙龈指数存在差异(P0.05)。结论:系统性行为预防及干预能够提高自闭症儿童的配合合作的程度及医嘱依从性,值得在口腔正畸科门诊自闭症儿童患者中推广。