Can phylogeny predict chemical diversity and potential medicinal activity of plants? A case study of amaryllidaceae

Background During evolution, plants and other organisms have developed a diversity of chemical defences, leading to the evolution of various groups of specialized metabolites selected for their endogenous biological function. A correlation between phylogeny and biosynthetic pathways could offer a predictive approach enabling more efficient selection of plants for the development of traditional medicine and lead discovery. However, this relationship has rarely been rigorously tested and the potential predictive power is consequently unknown.
Results We produced a phylogenetic hypothesis for the medicinally important plant subfamily Amaryllidoideae (Amaryllidaceae) based on parsimony and Bayesian analysis of nuclear, plastid, and mitochondrial DNA sequences of over 100 species. We tested if alkaloid diversity and activity in bioassays related to the central nervous system are significantly correlated with phylogeny and found evidence for a significant phylogenetic signal in these traits, although the effect is not strong.
Conclusions Several genera are non-monophyletic emphasizing the importance of using phylogeny for interpretation of character distribution. Alkaloid diversity and in vitro inhibition of acetylcholinesterase (AChE) and binding to the serotonin reuptake transporter (SERT) are significantly correlated with phylogeny. This has implications for the use of phylogenies to interpret chemical evolution and biosynthetic pathways, to select candidate taxa for lead discovery, and to make recommendations for policies regarding traditional use and conservation priorities.

ABCB1 polymorphism predicts escitalopram dose needed for remission in major depression

The ATP-binding cassette family of transporter proteins, subfamily B (MDR/TAP), member 1 (ABCB1) (P-glycoprotein) transporter is a key component of the blood–brain barrier. Many antidepressants are subject to ABCB1 efflux. Functional polymorphisms of ABCB1 may influence central nervous system bioavailability of antidepressants subject to efflux. Single-nucleotide polymorphisms (SNPs) at rs1045642 (C3435T) of ABCB1 have been associated with efflux pump efficiency. This may explain part of the interindividual variation in antidepressant dose needed to remit. Individuals (N=113) with DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) major depressive disorder (MDD) were treated with escitalopram (ESC) or venlafaxine (VEN) over 8 weeks. The17-item Hamilton Depression Rating Scale was assessed serially, blind to genotype. SNP rs1045642 of ABCB1 along with two SNPs previously reported to be in linkage disequilibrium with it (rs2032582 and rs1128503) were genotyped. Demographic features, clinical features, P450 metabolizer status and 5-HTTLPR (serotonin-transporter-linked promoter region) genotype were controlled for. Carriers of rs1045642 TT needed on average 11 mg of ESC to remit, whereas TC and CC carriers required 24 and 19 mg, respectively (P=0.0001). This equates to a 2.0- (95% confidence interval=1.5–3.4; P<0.001) fold greater ESC dose needed to remit for C carriers compared with TT carriers at rs1045642. Of VEN-treated subjects carrying TT genotype at rs1045642, 73.3% remitted compared with 12.5% for CC genotype (odds ratio=6.69; 95% confidence interval=1.72–25.9, P=0.006). These data suggest that antidepressant dose needed to remit can be predicted by an ABCB1 SNP. This has the potential clinical translation implications for dose selection and remission from MDD.

Rapid detection of SMARCB1 sequence variation using high resolution melting

Background : Rhabdoid tumors are rare cancers of early childhood arising in the kidney, central nervous system and other organs. The majority are caused by somatic inactivating mutations or deletions affecting the tumor suppressor locus SMARCB1 [OMIM 601607]. Germ-line SMARCB1 inactivation has been reported in association with rhabdoid tumor, epitheloid sarcoma and familial schwannomatosis, underscoring the importance of accurate mutation screening to ascertain recurrence and transmission risks. We describe a rapid and sensitive diagnostic screening method, using high resolution melting (HRM), for detecting sequence variations in SMARCB1. Methods : Amplicons, encompassing the nine coding exons of SMARCB1, flanking splice site sequences and the 5' and 3' UTR, were screened by both HRM and direct DNA sequencing to establish the reliability of HRM as a primary mutation screening tool. Reaction conditions were optimized with commercially available HRM mixes. Results : The false negative rate for detecting sequence variants by HRM in our sample series was zero. Nine amplicons out of a total of 140 (6.4%) showed variant melt profiles that were subsequently shown to be false positive. Overall nine distinct pathogenic SMARCB1 mutations were identified in a total of 19 possible rhabdoid tumors. Two tumors had two distinct mutations and two harbored SMARCB1 deletion. Other mutations were nonsense or frame-shifts. The detection sensitivity of the HRM screening method was influenced by both sequence context and specific nucleotide change and varied from 1: 4 to 1:1000 (variant to wild-type DNA). A novel method involving digital HRM, followed by re-sequencing, was used to confirm mutations in tumor specimens containing associated normal tissue. Conclusions : This is the first report describing SMARCB1 mutation screening using HRM. HRM is a rapid, sensitive and inexpensive screening technology that is likely to be widely adopted in diagnostic laboratories to facilitate whole gene mutation screening.

Localization of copper and copper transporters in the human brain

Disturbances in brain copper result in rare and severe neurological disorders and may play a role in the pathogenesis and progression of multiple neurodegenerative diseases. Our current understanding of mammalian brain copper transport is based on model systems outside the central nervous system and no data are available regarding copper transport systems in the human brain. To address this deficit, we quantified regional copper concentrations and examined the distribution and cellular localization of the copper transport proteins Copper transporter 1, Atox1, ATP7A, and ATP7B in multiple regions of the human brain using inductively coupled plasma-mass spectrometry, Western blot and immunohistochemistry. We identified significant relationships between copper transporter levels and brain copper concentrations, supporting a role for these proteins in copper transport in the human brain. Interestingly, the substantia nigra contained twice as much copper than that in other brain regions, suggesting an important role for copper in this brain region. Furthermore, ATP7A levels were significantly greater in the cerebellum, compared with other brain regions, supporting an important role for ATP7A in cerebellar neuronal health. This study provides novel data regarding copper regulation in the human brain, critical to understand the mechanisms by which brain copper levels can be altered, leading to neurological disease.

ADAMTS4 and ADAMTS5 knockout mice are protected from versican but not aggrecan or brevican proteolysis during spinal cord injury

The chondroitin sulfate proteoglycans (CSPGs) aggrecan, versican, and brevican are large aggregating extracellular matrix molecules that inhibit axonal growth of the mature central nervous system (CNS). ADAMTS proteoglycanases, including ADAMTS4 and ADAMTS5, degrade CSPGs, representing potential targets for ameliorating axonal growth-inhibition by CSPG accumulation after CNS injury. We investigated the proteolysis of CSPGs in mice homozygous for Adamts4 or Adamts5 null alleles after spinal cord injury (SCI). ADAMTS-derived 50-60 kDa aggrecan and 50 kDa brevican fragments were observed in Adamts4-/-, Adamts5-/-, and wt mice but not in the sham-operated group. By contrast Adamts4-/- and Adamts5-/- mice were both protected from versican proteolysis with an ADAMTS-generated 70 kDa versican fragment predominately observed in WT mice. ADAMTS1, ADAMTS9, and ADAMTS15 were detected by Western blot in Adamts4-/- mice' spinal cords after SCI. Immunohistochemistry showed astrocyte accumulation at the injury site. These data indicate that aggrecan and brevican proteolysis is compensated in Adamts4-/- or Adamts5-/- mice by ADAMTS proteoglycanase family members but a threshold of versican proteolysis is sensitive to the loss of a single ADAMTS proteoglycanase during SCI. We show robust ADAMTS activity after SCI and exemplify the requirement for collective proteolysis for effective CSPG clearance during SCI.

A five-gene hedgehog signature developed as a patient preselection tool for hedgehog inhibitor therapy in medulloblastoma

Purpose: 

Medulloblastoma Down Under 2013 : a report from the third annual meeting of the International Medulloblastoma Working Group.

Medulloblastoma is curable in approximately 70% of patients. Over the past decade, progress in improving survival using conventional therapies has stalled, resulting in reduced quality of life due to treatment-related side effects, which are a major concern in survivors. The vast amount of genomic and molecular data generated over the last 5-10 years encourages optimism that improved risk stratification and new molecular targets will improve outcomes. It is now clear that medulloblastoma is not a single-disease entity, but instead consists of at least four distinct molecular subgroups: WNT/Wingless, Sonic Hedgehog, Group 3, and Group 4. The Medulloblastoma Down Under 2013 meeting, which convened at Bunker Bay, Australia, brought together 50 leading clinicians and scientists. The 2-day agenda included focused sessions on pathology and molecular stratification, genomics and mouse models, high-throughput drug screening, and clinical trial design. The meeting established a global action plan to translate novel biologic insights and drug targeting into treatment regimens to improve outcomes. A consensus was reached in several key areas, with the most important being that a novel classification scheme for medulloblastoma based on the four molecular subgroups, as well as histopathologic features, should be presented for consideration in the upcoming fifth edition of the World Health Organization's classification of tumours of the central nervous system. Three other notable areas of agreement were as follows: (1) to establish a central repository of annotated mouse models that are readily accessible and freely available to the international research community; (2) to institute common eligibility criteria between the Children's Oncology Group and the International Society of Paediatric Oncology Europe and initiate joint or parallel clinical trials; (3) to share preliminary high-throughput screening data across discovery labs to hasten the development of novel therapeutics. Medulloblastoma Down Under 2013 was an effective forum for meaningful discussion, which resulted in enhancing international collaborative clinical and translational research of this rare disease. This template could be applied to other fields to devise global action plans addressing all aspects of a disease, from improved disease classification, treatment stratification, and drug targeting to superior treatment regimens to be assessed in cooperative international clinical trials.

Mind and body: how the health of the body impacts on neuropsychiatry

It has long been established in traditional forms of medicine and in anecdotal knowledge that the health of the body and the mind are inextricably linked. Strong and continually developing evidence now suggests a link between disorders which involve Hypothalamic-Pituitary-Adrenal axis (HPA) dysregulation and the risk of developing psychiatric disease. For instance, adverse or excessive responses to stressful experiences are built into the diagnostic criteria for several psychiatric disorders, including depression and anxiety disorders. Interestingly, peripheral disorders such as metabolic disorders and cardiovascular diseases are also associated with HPA changes. Furthermore, many other systemic disorders associated with a higher incidence of psychiatric disease involve a significant inflammatory component. In fact, inflammatory and endocrine pathways seem to interact in both the periphery and the central nervous system (CNS) to potentiate states of psychiatric dysfunction. This review synthesizes clinical and animal data looking at interactions between peripheral and central factors, developing an understanding at the molecular and cellular level of how processes in the entire body can impact on mental state and psychiatric health.

Therapeutic approaches to disease modifying therapy for multiple sclerosis in adults: an Australian and New Zealand perspective: part 1 historical and established therapies

Multiple sclerosis (MS) is a potentially life-changing immune mediated disease of the central nervous system. Until recently, treatment has been largely confined to acute treatment of relapses, symptomatic therapies and rehabilitation. Through persistent efforts of dedicated physicians and scientists around the globe for 160 years, a number of therapies that have an impact on the long term outcome of the disease have emerged over the past 20 years. In this three part series we review the practicalities, benefits and potential hazards of each of the currently available and emerging treatment options for MS. We pay particular attention to ways of abrogating the risks of these therapies and provide advice on the most appropriate indications for using individual therapies. In Part 1 we review the history of the development of MS therapies and its connection with the underlying immunobiology of the disease. The established therapies for MS are reviewed in detail and their current availability and indications in Australia and New Zealand are summarised. We examine the evidence to support their use in the treatment of MS.

Serum levels of brain-derived neurotrophic factor in patients with schizophrenia and bipolar disorder.

There is evidence that major psychiatric discords such as schizophrenia (SZ) and bipolar disorder (BD) are associated with dysregulation of synaptic plasticity with downstream alterations of neurotrophins. Brain-derived neurotrophic factor (BDNF) is the most widely distributed neurotrophin in the central nervous system (CNS), and performs many biological functions such as promoting the survival, differentiation, and plasticity of neurons. Variants in the BDNF gene increase the risk of SZ and bipolar disorder. Chronic administration of drugs used to treat SZ and BD, such as lithium, valproate, quetiapine, clozapine, and olanzapine, increases BDNF expression in rat brain. To examine serum BDNF, three groups of chronically medicated DSM-IV SZ patients, on treatment with clozapine (n=27), typical (n=14), and other atypical antipsychotics (n=19), 30 euthymic BD patients, and 26 healthy control had 5 ml blood samples collected by venipuncture. Serum BDNF levels were significantly higher in SZ patients (p<0.001) when compared to either controls or euthymic BD patients. Increased BDNF in SZ patients might be related to the course of illness or to treatment variables. Prospective studies are warranted.

Nanomedicine based nanoparticles for neurological disorders

Human health is severely hampered by a majority of the neurological disorders such as the brain tumors, degenerative Alzheimer's disease, Parkinson's disease and those involving inflammatory component. Owing to the stringent protection offered by the blood brain barrier, conventional therapeutics gain limited access and therefore, are therapeutically suboptimal. Hence, research has now focused to develop the novel drug delivery systems with a prime motto of maintaining therapeutic drug levels inside the brain, avoiding non-specific tissue distribution. The introduction of nanotechnology has addressed few of these objectives and opened up new avenues for even more improvization. To some extent, nanodelivery systems were successful in crossing the blood brain barrier and accessing the remote areas of the brain. They also have shown tremendous potential in delivering the therapeutic and diagnostic aids following systemic administration. What revolutionised the nano applications is the development of "smart" nanosystems, whose surface is tailor made for the effective theranostic delivery. However, a detailed understanding of the long term nanoformulation toxicities, along with the neuropathology, is the critical future question to be addressed. In this review, a brief introduction of the prominent neurological disorders and detailed applications of nanotechnology are discussed.

Mitochondrial dysfunction in the pathophysiology of bipolar disorder: effects of pharmacotherapy

Bipolar disorder is a common, chronic, and complex mental illness. Bipolar disorder is frequently comorbid with primary mitochondrial and metabolic disorders, and studies have implicated mitochondrial dysfunction in its pathophysiology. In the brains of people with bipolar disorder, high-energy phosphates are decreased, lactate is elevated and pH decreased, which together suggest a shift toward glycolysis for energy production. Furthermore, oxidative stress is increased, and calcium signalling dysregulated. Additionally there is downregulation of the expression of mitochondrial complexes, especially complex I. The therapeutic effects of some bipolar disorder drugs have recently been shown to be related to these mechanisms. In this review we will evaluate current research on the interactions between mitochondrial dysfunction and bipolar disorder pathology. We will then appraise the current literature describing the effects of bipolar disorder drugs on mitochondrial function, and discuss ramifications for future research.

Metabotropic glutamate receptors as targets for novel antipsychotic treatments

In recent years metabotropic glutamate receptors have emerged as key targets for the design of new antipsychotic medications for schizophrenia, in particular mGluR5 and mGluR2/3. These receptors exhibit diverse interactions with other neurotransmitter receptors and critical elements of intracellular signalling cascades known to be important to the pharmacotherapy of schizophrenia. In addition, mGluR5 and mGluR2/3 are intimately involved in behavioural domains related to the symptoms of this disorder. Both animal and clinical studies using novel drugs targeting these receptors have provided encouraging results. The number of patents registered for drugs targeting metabotropic glutamate receptors has grown dramatically, and positive allosteric modulators for both receptors show particular promise.

Aptamer-targeted oligonucleotide theranostics: a smarter approach for brain delivery and the treatment of neurological diseases

Aptamers represent the novel class of oligonucleotides holding multiple applications in the area of biomedicine. The advancements introduced with the Systematic Evolution of Ligands by EXponential enrichment (SELEX) approach further eased the scope of producing modified aptamers within a short span yet retaining the properties of stability and applicability. In the recent times, aptamers were identified to have the potential for penetrating into the deep human crevices and thus can be utilized in addressing the issues of complex neurological disorders. Considering the specificity and stability enhancement by chemical modifications, aptamer-based nanotechnologies may have great potential for future therapeutics and diagnostics (theranostics). The research community has already witnessed success with the approval of macugen (an anti-vascular endothelial growth factor aptamer) for treating degenerating eye disease, and hopefully those that are in the clinical trials will soon be translated for human application. Herein, we have summarized the aptamer chemistry, aptamer-nanoconjugates and their applications against neurological diseases.

Analysis of phasic and tonic electromyographic signal characteristics: electromyographic synthesis and comparison of novel morphological and linear-envelope approaches

The pattern of tonic and phasic components in an EMG signal reflects the underlying behaviour of the central nervous system (CNS) in controlling the musculature. One avenue for gaining a better understanding of this behaviour is to seek a quantitative characterisation of these phasic and tonic components. We propose that these signal characteristics can range between unvarying, tonic and intermittent, phasic activation through a continuum of EMG amplitude modulation. In this paper, we present two new algorithms for quantifying amplitude modulation: a linear-envelope approach, and a mathematical morphology approach. In addition we present an algorithm for synthesising EMG signals with known amplitude modulation. The efficacy of the synthesis algorithm is demonstrated using real EMG data. We present an evaluation and comparison of the two algorithms for quantifying amplitude modulation based on synthetic data generated by the proposed synthesis algorithm. The results demonstrate that the EMG synthesis parameters represent 91.9% and 96.2% of the variance of linear-envelopes extracted from lumbo-pelvic muscle EMG signals collected from subjects performing a repetitive-movement task. This depended, however, on the muscle and movement-speed considered (F=4.02, p<0.001). Coefficients of determination between input and output amplitude modulation variables were used to quantify the accuracy of the linear-envelope and morphological signal processing algorithms. The linear-envelope algorithm exhibited higher coefficients of determination than the most accurate morphological approach (and hence greater accuracy, T=8.16, p<0.001). Similarly, the standard deviation of the coefficients of determination was 1.691 times smaller (p<0.001). This signal processing algorithm represents a novel tool for the quantification of amplitude modulation in continuous EMG signals and can be used in the study of CNS motor control of the musculature in repetitive-movement tasks.