Betaine-The dark knight of the brain

The role of betaine in the liver and kidney has been well documented, even from the cellular and molecular point of view. Despite literature reporting positive effects of betaine supplementation in Alzheimer's, Parkinson's and schizophrenia, the role and function of betaine in the brain are little studied and reviewed. Beneficial effects of betaine in neurodegeneration, excitatory and inhibitory imbalance and against oxidative stress in the central nervous system (CNS) have been collected and analysed to understand the main role of betaine in the brain. There are many 'dark' aspects needed to complete the picture. The understanding of how this osmolyte is transported across neuron and glial cells is also controversial, as the expression levels and functioning of the known protein capable to transport betaine expressed in the brain, betaine-GABA transporter 1 (BGT-1), is itself not well clarified. The reported actions of betaine beyond BGT-1 related to neuronal degeneration and memory impairment are the focus of this work. With this review, we underline the scarcity of detailed molecular and cellular information about betaine action. Consequently, the requirement of detailed focus on and study of the interaction of this molecule with CNS components to sustain the therapeutic use of betaine

Neuromuscular magnetic stimulation counteracts muscle decline in ALS patients: results of a randomized, double-blind, controlled study

The aim of the study was to verify whether neuromuscular magnetic stimulation (NMMS) improves muscle function in spinal-onset amyotrophic lateral sclerosis (ALS) patients. Twenty-two ALS patients were randomized in two groups to receive, daily for two weeks, NMMS in right or left arm (referred to as real-NMMS, rNMMS), and sham NMMS (sNMMS) in the opposite arm. All the patients underwent a median nerve conduction (compound muscle action potential, CMAP) study and a clinical examination that included a handgrip strength test and an evaluation of upper limb muscle strength by means of the Medical Research Council Muscle Scale (MRC). Muscle biopsy was then performed bilaterally on the flexor carpi radialis muscle to monitor morpho-functional parameters and molecular changes. Patients and physicians who performed examinations were blinded to the side of real intervention. The primary outcome was the change in the muscle strength in upper arms. The secondary outcomes were the change from baseline in the CMAP amplitudes, in the nicotinic ACh currents, in the expression levels of a selected panel of genes involved in muscle growth and atrophy, and in histomorphometric parameters of ALS muscle fibers. The Repeated Measures (RM) ANOVA with a Greenhouse-Geisser correction (sphericity not assumed) showed a significant effect [F(3, 63) = 5.907, p < 0.01] of rNMMS on MRC scale at the flexor carpi radialis muscle, thus demonstrating that the rNMMS significantly improves muscle strength in flexor muscles in the forearm. Secondary outcomes showed that the improvement observed in rNMMS-treated muscles was associated to counteracting muscle atrophy, down-modulating the proteolysis, and increasing the efficacy of nicotinic ACh receptors (AChRs). We did not observe any significant difference in pre- and post-stimulation CMAP amplitudes, evoked by median nerve stimulation. This suggests that the improvement in muscle strength observed in the stimulated arm is unlikely related to reinnervation. The real and sham treatments were well tolerated without evident side effects. Although promising, this is a proof of concept study, without an immediate clinical translation, that requires further clinical validation

Trafficking of the glutamate transporter is impaired in LRRK2-related Parkinson's disease

The Excitatory Amino Acid Transporter 2 (EAAT2) accounts for 80% of brain glutamate clearance and is mainly expressed in astrocytic perisynaptic processes. EAAT2 function is finely regulated by endocytic events, recycling to the plasma membrane and degradation. Noteworthy, deficits in EAAT2 have been associated with neuronal excitotoxicity and neurodegeneration. In this study, we show that EAAT2 trafficking is impaired by the leucine-rich repeat kinase 2 (LRRK2) pathogenic variant G2019S, a common cause of late-onset familial Parkinson’s disease (PD). In LRRK2 G2019S human brains and experimental animal models, EAAT2 protein levels are significantly decreased, which is associated with elevated gliosis. The decreased expression of the transporter correlates with its reduced functionality in mouse LRRK2 G2019S purified astrocytic terminals and in Xenopus laevis oocytes expressing human LRRK2 G2019S. In LRRK2 G2019S knock-in mouse brain, the correct surface localization of the endogenous transporter is impaired, resulting in its interaction with a plethora of endo-vesicular proteins. Mechanistically, we report that pathogenic LRRK2 kinase activity delays the recycling of the transporter to the plasma membrane via Rabs inactivation, causing its intracellular re-localization and degradation. Taken together, our results demonstrate that pathogenic LRRK2 interferes with the physiology of EAAT2, pointing to extracellular glutamate overload as a possible contributor to neurodegeneration in PD

Novel approaches to study the involvement of α7-nAChR in human diseases

The alpha7 nicotinic acetylcholine receptor (α7 nAChR) is widely distributed in the human brain and has been implicated in a number of human central nervous system (CNS) diseases, including Alzheimer's and Parkinson's disease, schizophrenia and autism. Recently, new roles for α7 nAChRs in lung cancer and heart disease have been elucidated. Despite the importance of this receptor in human pathology, many technical difficulties are still encountered when investigating the role of α7 nAChRs. Electrophysiological analysis of the receptor upon heterologous expression or in human tissues was limited by the fast desensitization of α7-mediated nicotinic currents and by tissue availability. In addition, animal models for the human diseases related to α7 nAChRs have long been unavailable. The recent development of new imaging and analysis approaches such as PET and receptor microtransplantation have rendered the study of α7 nAChRs increasingly feasible, paving new roads to the design of therapeutic drugs. This review summarizes the current knowledge and recent findings obtained by these novel approaches. © 2012 Bentham Science Publishers

The &ldquo;www&rdquo; of Xenopus laevis Oocytes: The Why, When, What of Xenopus laevis Oocytes in Membrane Transporters Research

After 50 years, the heterologous expression of proteins in Xenopus laevis oocytes is still essential in many research fields. New approaches and revised protocols, but also classical methods, such as the two-electrode voltage clamp, are applied in studying membrane transporters. New and old methods for investigating the activity and the expression of Solute Carriers (SLC) are reviewed, and the kinds of experiment that are still useful to perform with this kind of cell are reported. Xenopus laevis oocytes at the full-grown stage have a highly efficient biosynthetic apparatus that correctly targets functional proteins at the defined compartment. This small protein factory can produce, fold, and localize almost any kind of wild-type or recombinant protein; some tricks are required to obtain high expression and to verify the functionality. The methodologies examined here are mainly related to research in the field of membrane transporters. This work is certainly not exhaustive; it has been carried out to be helpful to researchers who want to quickly find suggestions and detailed indications when investigating the functionality and expression of the different members of the solute carrier families

Modulation of GABAA receptors in the treatment of epilepsy

A variety of evidence suggested that an imbalance in excitatory and inhibitory neurotransmission could be one of the pathophysiological mechanisms underlying the occurrence and progression of seizures. Understanding the causes of this imbalance may provide essential insight into the basic mechanisms of epilepsy and may uncover novel targets for future drug therapies. Accordingly, GABA is the most important inhibitory neurotransmitter in the CNS and its receptors (e.g., GABAARs) can still be relevant targets of new antiepileptic drugs (AEDs).BACKGROUND: A variety of evidence suggested that an imbalance in excitatory and inhibitory neurotransmission could be one of the pathophysiological mechanisms underlying the occurrence and progression of seizures. Understanding the causes of this imbalance may provide essential insight into the basic mechanisms of epilepsy and may uncover novel targets for future drug therapies. Accordingly, GABA is the most important inhibitory neurotransmitter in the CNS and its receptors (e.g., GABAARs) can still be relevant targets of new antiepileptic drugs (AEDs). METHODS: Up to now, a variety of modulating agents that directly or indirectly act at GABAARs have been proposed for restoring the physiological balance of excitation and inhibition in the epileptogenic brain. While benzodiazepine, barbiturates and allosteric modulators of GABAARs are well-known for their anticonvulsant effect, new compounds as modulators of chloride homeostasis or phytocannabinoids are not completely unraveled and their antiepileptic action is still matter of debate. In addition, several inflammatory mediators as cytokines and chemokines play an important role in the modulation of GABAAR function, even if further research is needed to translate these new findings from the bench to the bedside. Finally yet importantly, a new frontier in epilepsy research is represented by the observation that specific small noncoding RNAs, namely miRNAs, may regulate GABAAR function paving the road to therapeutic approaches based on the modulation of gene expression. CONCLUSION: Here, we review key physiological, neuropathological and functional studies that altogether strengthen the role of modulation of GABAARs function as therapeutic target. The discovery of the novel molecular mechanisms underlying the GABAergic transmission in epilepsy represents another heavy piece in the "epileptic puzzle". Even if GABAAR is an old story in the pharmacology of the epilepsy, the reviewed findings suggest that new players in the scenario need to be considered

Physiological characterization of human muscle acetylcholine receptors from ALS patients

Amyotrophic lateral sclerosis (ALS) is characterized by progressive degeneration of motor neurons leading to muscle paralysis. Research in transgenic mice suggests that the muscle actively contributes to the disease onset, but such studies are difficult to pursue in humans and in vitro models would represent a good starting point. In this work we show that tiny amounts of muscle from ALS or from control denervated muscle, obtained by needle biopsy, are amenable to functional characterization by two different technical approaches: "microtransplantation" of muscle membranes into Xenopus oocytes and culture of myogenic satellite cells. Acetylcholine (ACh)-evoked currents and unitary events were characterized in oocytes and multinucleated myotubes. We found that ALS acetylcholine receptors (AChRs) retain their native physiological characteristics, being activated by ACh and nicotine and blocked by alpha-bungarotoxin (alpha-BuTX), d-tubocurarine (dTC), and galantamine. The reversal potential of ACh-evoked currents and the unitary channel behavior were also typical of normal muscle AChRs. Interestingly, in oocytes injected with muscle membranes derived from ALS patients, the AChRs showed a significant decrease in ACh affinity, compared with denervated controls. Finally, riluzole, the only drug currently used against ALS, reduced, in a dose-dependent manner, the ACh-evoked currents, indicating that its action remains to be fully characterized. The two methods described here will be important tools for elucidating the role of muscle in ALS pathogenesis and for developing drugs to counter the effects of this disease

Physiological characterization of human muscle acetylcholine receptors from ALS patients

Amyotrophic lateral sclerosis (ALS) is characterized by progressive degeneration of motor neurons leading to muscle paralysis. Research in transgenic mice suggests that the muscle actively contributes to the disease onset, but such studies are difficult to pursue in humans and in vitro models would represent a good starting point. In this work we show that tiny amounts of muscle from ALS or from control denervated muscle, obtained by needle biopsy, are amenable to functional characterization by two different technical approaches: "microtransplantation" of muscle membranes into Xenopus oocytes and culture of myogenic satellite cells. Acetylcholine (ACh)-evoked currents and unitary events were characterized in oocytes and multinucleated myotubes. We found that ALS acetylcholine receptors (AChRs) retain their native physiological characteristics, being activated by ACh and nicotine and blocked by alpha-bungarotoxin (alpha-BuTX), d-tubocurarine (dTC), and galantamine. The reversal potential of ACh-evoked currents and the unitary channel behavior were also typical of normal muscle AChRs. Interestingly, in oocytes injected with muscle membranes derived from ALS patients, the AChRs showed a significant decrease in ACh affinity, compared with denervated controls. Finally, riluzole, the only drug currently used against ALS, reduced, in a dose-dependent manner, the ACh-evoked currents, indicating that its action remains to be fully characterized. The two methods described here will be important tools for elucidating the role of muscle in ALS pathogenesis and for developing drugs to counter the effects of this disease

Same riot/demo, different views (guest blog)

By Shakuntala Banaji In riposte to various UK newspapers’ and news channels’ conservative versions of reality, I would like to give an alternative account of what happened on the November 10th NUS and UCU demonstration against student fees and on the break-away part of it at 30 Millbank, the Conservative party HQ