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Background and purpose:Illegal ‘ecstasy’ tablets frequently contain 3,4-methylenedioxymethamphetamine (MDMA)-like compounds of unknown pharmacological activity. Since monoamine transporters are one of the primary targets of MDMA action in the brain, a number of MDMA analogues have been tested for their ability to inhibit [3H]noradrenaline uptake into rat PC12 cells expressing the noradrenaline transporter (NET) and [3H]5-HT uptake into HEK293 cells stably transfected with the 5-HT transporter (SERT).Experimental approach:Concentration–response curves for the following compounds at both NET and SERT were determined under saturating substrate conditions: 4-hydroxy-3-methoxyamphetamine (HMA), 4-hydroxy-3-methoxymethamphetamine (HMMA), 3,4-methylenedioxy-N-hydroxyamphetamine (MDOH), 2,5-dimethoxy-4-bromophenylethylamine (2CB), 3,4-dimethoxymethamphetamine (DMMA), 3,4-methylenedioxyphenyl-2-butanamine (BDB), 3,4-methylenedioxyphenyl-N-methyl-2-butanamine (MBDB) and 2,3-methylenedioxymethamphetamine (2,3-MDMA).Key results:2,3-MDMA was significantly less potent than MDMA at SERT, but equipotent with MDMA at NET. 2CB and BDB were both significantly less potent than MDMA at NET, but equipotent with MDMA at SERT. MBDB, DMMA, MDOH and the MDMA metabolites HMA and HMMA, were all significantly less potent than MDMA at both NET and SERT.Conclusions and implications:This study provides an important insight into the structural requirements of MDMA analogue affinity at both NET and SERT. It is anticipated that these results will facilitate understanding of the likely pharmacological actions of structural analogues of MDMA.British Journal of Pharmacology (2007) 152, 1121–1130; doi:10.1038/sj.bjp.0707473; published online 24 September 2007 [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting motor neurons, with a typical lifespan of 3-5 years. Altered metabolism is a key feature of ALS that strongly influences prognosis, with an increase in whole-body energy expenditure and changes in skeletal muscle metabolism, including greater reliance on fat oxidation. Dyslipidemia has been described in ALS as part of the metabolic dysregulation, but its role in the pathophysiology of the disease remains controversial. Among the lipids, cholesterol is of particular interest as a vital component of cell membranes, playing a key role in signal transduction and mitochondrial function in muscle. The aim of this study was to investigate whether motor dysfunction in ALS might be associated with dysregulation of muscle cholesterol metabolism. We determined cholesterol content and analyzed the expression of key determinants of the cholesterol metabolism pathway in muscle biopsies from thirteen ALS patients and ten asymptomatic ALS-mutation gene carriers compared to sixteen controls. Using human control primary myotubes, we further investigated the potential contribution of cholesterol dyshomeostasis to reliance on mitochondrial fatty acid. We found that cholesterol accumulates in the skeletal muscle of ALS patients and that cholesterol overload significantly correlates with disease severity evaluated by the Revised ALS Functional Rating Scale. These defects are associated with overexpression of the genes of the lysosomal cholesterol transporters Niemann-Pick type C1 (NPC1) and 2 (NPC2), which are required for cholesterol transfer from late endosomes/lysosomes to cellular membranes. Most notably, a significant increase in NPC2 mRNA levels could be detected in muscle samples from asymptomatic ALS-mutation carriers, long before disease onset. We found that filipin-stained unesterified cholesterol accumulated in the lysosomal compartment in ALS muscle samples, suggesting dysfunction of the NPC1/2 system. Accordingly, we report here that experimental NPC1 inhibition or lysosomal pH alteration in human primary myotubes was sufficient to induce the overexpression of NPC1 and NPC2 mRNA. Finally, acute NPC1 inhibition in human control myotubes induced a shift towards a preferential use of fatty acids, thus reproducing the metabolic defect characteristic of ALS muscle. We conclude that cholesterol homeostasis is dysregulated in ALS muscle from the presymptomatic stage. Targeting NPC1/2 dysfunction may be a new therapeutic strategy for ALS to restore muscle energy metabolism and slow motor symptom progression., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Six genes encoding putative high molecular weight penicillin-binding proteins (Pbp) are present in the genome of the β-lactam-resistant strain Corynebacterium jeikeium K411. In this study, we show that pbp2c , one of these six genes, is present in resistant strains of Corynebacteriaceae but absent from sensitive strains. The molecular study of the pbp2c locus from C. jeikeium and its heterologous expression in Corynebacterium glutamicum allowed us to show that Pbp2c confers high levels of β-lactam resistance to the host and is under the control of a β-lactam-induced regulatory system encoded by two adjacent genes, jk0410 and jk0411 . The detection of this inducible resistance may require up to 48 h of incubation, particularly in Corynebacterium amycolatum . Finally, the Pbp2c-expressing strains studied were resistant to all the β-lactam antibiotics tested, including carbapenems, ceftaroline, and ceftobiprole., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Lavollay, Buon, Le Moigne, Compain, Guyonvarch and Fonvielle.)

Congenital myasthenic syndromes (CMS) are a clinically and genetically heterogeneous group of rare diseases due to mutations in neuromuscular junction (NMJ) protein-coding genes. Until now, many mutations encoding postsynaptic proteins as Agrin, MuSK and LRP4 have been identified as responsible for increasingly complex CMS phenotypes. The majority of mutations identified in LRP4 gene causes bone diseases including CLS and sclerosteosis-2 and rare cases of CMS with mutations in LRP4 gene has been described so far. In the French cohort of CMS patients, we identified a novel LRP4 homozygous missense mutation (c.1820A > G; p.Thy607Cys) within the β1 propeller domain in a patient presenting CMS symptoms, including muscle weakness, fluctuating fatigability and a decrement in compound muscle action potential in spinal accessory nerves, associated with congenital agenesis of the hands and feet and renal malformation. Mechanistic expression studies show a significant decrease of AChR aggregation in cultured patient myotubes, as well as altered in vitro binding of agrin and Wnt11 ligands to the mutated β1 propeller domain of LRP4 explaining the dual phenotype characterized clinically and electoneuromyographically in the patient. These results expand the LRP4 mutations spectrum associated with a previously undescribed clinical association involving impaired neuromuscular transmission and limb deformities and highlighting the critical role of a yet poorly described domain of LRP4 at the NMJ. This study raises the question of the frequency of this rare neuromuscular form and the future diagnosis and management of these cases., (© 2023. Springer Nature Limited.)

The development of the neuromuscular junction (NMJ) requires dynamic trans-synaptic coordination orchestrated by secreted factors, including Wnt family morphogens. To investigate how these synaptic cues in NMJ development are transduced, particularly in the regulation of acetylcholine receptor (AChR) accumulation in the postsynaptic membrane, we explored the function of Van Gogh-like protein 2 (Vangl2), a core component of Wnt planar cell polarity signaling. We found that conditional, muscle-specific ablation of Vangl2 in mice reproduced the NMJ differentiation defects seen in mice with global Vangl2 deletion. These alterations persisted into adulthood and led to NMJ disassembly, impaired neurotransmission, and deficits in motor function. Vangl2 and the muscle-specific receptor tyrosine kinase MuSK were functionally associated in Wnt signaling in the muscle. Vangl2 bound to and promoted the signaling activity of MuSK in response to Wnt11. The loss of Vangl2 impaired RhoA activation in cultured mouse myotubes and caused dispersed, rather than clustered, organization of AChRs at the postsynaptic or muscle cell side of NMJs in vivo. Our results identify Vangl2 as a key player of the core complex of molecules shaping neuromuscular synapses and thus shed light on the molecular mechanisms underlying NMJ assembly.

Objective: To report the identification of 2 new homozygous recessive mutations in the synaptotagmin 2 ( SYT2 ) gene as the genetic cause of severe and early presynaptic forms of congenital myasthenic syndromes (CMSs)., Methods: Next-generation sequencing identified new homozygous intronic and frameshift mutations in the SYT2 gene as a likely cause of presynaptic CMS. We describe the clinical and electromyographic patient phenotypes, perform ex vivo splicing analyses to characterize the effect of the intronic mutation on exon splicing, and analyze the functional impact of this variation at the neuromuscular junction (NMJ)., Results: The 2 infants presented a similar clinical phenotype evoking first a congenital myopathy characterized by muscle weakness and hypotonia. Next-generation sequencing allowed to the identification of 1 homozygous intronic mutation c.465+1G>A in patient 1 and another homozygous frameshift mutation c.328_331dup in patient 2, located respectively in the 5' splice donor site of SYT2 intron 4 and in exon 3. Functional studies of the intronic mutation validated the abolition of the splice donor site of exon 4 leading to its skipping. In-frame skipping of exon 4 that encodes part of the C2A calcium-binding domain of SYT2 is associated with a loss-of-function effect resulting in a decrease of neurotransmitter release and severe pre- and postsynaptic NMJ defects., Conclusions: This study identifies new homozygous recessive SYT2 mutations as the underlying cause of severe and early presynaptic form of CMS expanding the genetic spectrum of recessive SYT2 -related CMS associated with defects in neurotransmitter release., (Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

The neuromuscular junction (NMJ) is one of the best-studied cholinergic synapses. Inherited defects of peripheral neurotransmission result in congenital myasthenic syndromes (CMSs), a clinically and genetically heterogeneous group of rare diseases with fluctuating fatigable muscle weakness as the clinical hallmark. Whole-exome sequencing and Sanger sequencing in six unrelated families identified compound heterozygous and homozygous mutations in SLC5A7 encoding the presynaptic sodium-dependent high-affinity choline transporter 1 (CHT), which is known to be mutated in one dominant form of distal motor neuronopathy (DHMN7A). We identified 11 recessive mutations in SLC5A7 that were associated with a spectrum of severe muscle weakness ranging from a lethal antenatal form of arthrogryposis and severe hypotonia to a neonatal form of CMS with episodic apnea and a favorable prognosis when well managed at the clinical level. As expected given the critical role of CHT for multisystemic cholinergic neurotransmission, autonomic dysfunctions were reported in the antenatal form and cognitive impairment was noticed in half of the persons with the neonatal form. The missense mutations induced a near complete loss of function of CHT activity in cell models. At the human NMJ, a delay in synaptic maturation and an altered maintenance were observed in the antenatal and neonatal forms, respectively. Increased synaptic expression of butyrylcholinesterase was also observed, exposing the dysfunction of cholinergic metabolism when CHT is deficient in vivo. This work broadens the clinical spectrum of human diseases resulting from reduced CHT activity and highlights the complexity of cholinergic metabolism at the synapse., (Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Purinergic receptor P2X3 has been linked to analgesia in a number of pre-clinical models of pain, and is expressed in the human pain perception pathway. Only few P2X3-selective antagonists have been reported to date. This Letter describes the SAR and in vivo analgesic profile of a novel scaffold of selective P2X3 antagonists., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

1. This study examined the effects of chronic exposure of rats to 3,4-methylenedioxymethamphetamine (MDMA) on [(3)H]5-hydroxytryptamine ([(3)H]5-HT) re-uptake into purified rat brain synaptosomes, 5-HT-induced isometric contraction of aortic rings and [(3)H]5-HT re-uptake into rat aorta. 2. Rats were administered MDMA (20 mg kg(-1) i.p.) twice daily over 4 days. One, 7, 14 or 21 days post treatment, whole brain synaptosomes and descending thoracic aortic rings were prepared for investigation. 3. Chronic MDMA treatment significantly reduced the maximum rate (V(max)) of specific high-affinity [(3)H]5-HT re-uptake 1 day after treatment and for up to 21 days post-final administration of MDMA. Direct application of MDMA (100 microM) abolished synaptosomal re-uptake of [(3)H]5-HT in vitro. 4. Chronic MDMA administration significantly reduced the maximum contraction (E(max)) to 5-HT at 1 and 7 days after treatment, but not at 14 or 21 days. 5. Chronic MDMA administration had no effect on sodium-dependent [(3)H]5-HT re-uptake into aorta 1 day after treatment, nor did 100 microM MDMA have any direct effect on [(3)H]5-HT uptake into aortic rings in vitro. 6. These results show, for the first time, an altered responsiveness of vascular tissue to MDMA after chronic administration. In addition, they demonstrate a difference in the sensitivity of central and peripheral 5-HT uptake systems to chronic MDMA exposure, and suggest that the action of MDMA in the cardiovascular system does not arise from a direct effect of MDMA on peripheral 5-HT transport.