No abstract

Speech-related changes in regional cerebral blood flow (rCBF) were measured using H(2)(15)O positron-emission tomography in 9 adults with adductor spasmodic dysphonia (ADSD) before and after botulinum toxin (BTX) injection and 10 age- and gender-matched volunteers without neurological disorders. Scans were acquired at rest and during production of continuous narrative speech and whispered speech. Speech was recorded during scan acquisition for offline quantification of voice breaks, pitch breaks, and percentage aperiodicity to assess correlations between treatment-related changes in rCBF and clinical improvement. Results demonstrated that speech-related responses in heteromodal sensory areas were significantly reduced in persons with ADSD, compared with volunteers, before the administration of BTX. Three to 4 weeks after BTX injection, speech-related responses were significantly augmented in these regions and in left hemisphere motor areas commonly associated with oral-laryngeal motor control. This pattern of responses was most strongly correlated with the objective measures of clinical improvement (decreases in the frequency of voice breaks, pitch breaks, and percentage aperiodicity). These data suggest a pathophysiological model for ADSD in which BTX treatment results in more efficient cortical processing of sensory information, making this information available to motor areas that use it to more effectively regulate laryngeal movements.

No abstract

Solute carrier family 41 member A1 (SLC41A1) has been suggested to mediate magnesium (Mg 2+ ) transport by several in vitro studies. However, the physiological function of SLC41A1 remains to be elucidated. In this study, cellular Mg 2+ transport assays combined with zebrafish slc41a1 knockdown experiments were performed to disclose SLC41A1 function and its physiological relevance. The gene slc41a1 is ubiquitously expressed in zebrafish tissues and is regulated by water and dietary Mg 2+ availability. Knockdown of slc41a1 in zebrafish larvae grown in a Mg 2+ -free medium resulted in a unique phenotype characterized by a decrease in zebrafish Mg content. This decrease shows that SLC41A1 is required to maintain Mg 2+ balance and its dysfunction results in renal Mg 2+ wasting in zebrafish larvae. Importantly, the Mg content of the larvae is rescued when mouse SLC41A1 is expressed in slc41a1 -knockdown zebrafish. Conversely, expression of mammalian SLC41A1-p.Asp262Ala, harboring a mutation in the ion-conducting SLC41A1 pore, did not reverse the renal Mg 2+ wasting. 25 Mg 2+ transport assays in human embryonic kidney 293 (HEK293) cells overexpressing SLC41A1 demonstrated that SLC41A1 mediates cellular Mg 2+ extrusion independently of sodium (Na + ). In contrast, SLC41A1-p.Asp262Ala expressing HEK293 cells displayed similar Mg 2+ extrusion activities than control (mock) cells. In polarized Madin-Darby canine kidney cells, SLC41A1 localized to the basolateral cell membrane. Our results demonstrate that SLC41A1 facilitates renal Mg 2+ reabsorption in the zebrafish model. Furthermore, our data suggest that SLC41A1 mediates both Mg 2+ uptake and extrusion. Electronic supplementary material The online version of this article (10.1007/s00424-018-2234-9) contains supplementary material, which is available to authorized users.

Despite the enormous disease burden associated with dengue virus infections, a licensed antiviral drug is lacking. Here, we show that the paracetamol (acetaminophen) metabolite AM404 inhibits dengue virus replication. Moreover, we find that mutations in NS4B that were previously found to confer resistance to the antiviral compounds NITD-618 and SDM25N also render dengue virus insensitive to AM404. Our work provides further support for NS4B as a direct or indirect target for antiviral drug development. Dengue virus (DENV) is a major health concern. The virus was initially estimated to cause 50 million to 100 million infections each year (1, 2), but more recent estimates suggest even greater numbers (390 million infections, of which 96 million manifest clinically) (3). Dengue is a mosquito-transmitted infection that was once considered a tropical disease, but the virus is spreading rapidly across the globe and is now endemic in 128 countries, with up to 4 billion people at risk of infection (1, 4-7). No specific drug or licensed vaccine is available for DENV infection, leaving vector control the only option to prevent transmission, although this approach is threatened by the emergence of insecticide resistance (8-10). A specific antiviral therapeutic agent would be an important tool to inhibit virus replication and transmission and to reduce the global burden of DENV.To identify new inhibitors of DENV replication, we screened the NIH Clinical Collection, a library of small molecules with a history of use in humans, using a replicon-based assay in HeLa cells (11). In this DENV serotype 2 (DENV2) (strain New Guinea C [NGC])-based replicon (RepDVPacLuc), the structural genes are replaced by a puromycin resistance gene and a firefly luciferase (FLuc) reporter gene, which can be assessed as a readout for virus replication (11,12). AM404 (PubChem identification no. 6604822) was one of the compounds that, at a concentration of 10 M, reduced FLuc activity in HeLa DENV2 replicon cells by Ͼ50%, relative to the dimethyl sulfoxide (DMSO) control, without affecting cell viability by Ͼ20%. AM404, also known as Narachidonoylphenolamine, is an active metabolite of paracetamol (acetaminophen) (Fig. 1A) and is suggested to be responsible for all or part of its analgesic activity (13,14).To confirm the results from our screen, we analyzed an independent batch of AM404 (Tocris Bioscience; purity, 99.5% by HPLC) for antiviral activity on HeLa DENV2 replicon cells and found that AM404, but not paracetamol, reduced FLuc activity in a dose-dependent manner (50% effective concentration [EC 50 ], 3.6 M [95% confidence interval [CI], 3.0 to 4.2 M]) (Fig. 1B). As expected (15-17), the nucleoside analogue ribavirin (SigmaAldrich), which was used as a positive control, also inhibited virus replication in a dose-dependent manner (EC 50 , 2.2 M [95% CI, 1.8 to 2.6 M]) (Fig. 1B). Importantly, none of the compounds affected cell viability, as assessed by a colorimetric assay for cell metabolic activity (Fig. 1B). We next analyzed whether AM404 al...