A novel combination treatment for fragile X syndrome predicted using computational methods.

Fragile X syndrome is a neurodevelopmental disorder caused by silencing of the fragile X messenger ribonucleotide gene. Patients display a wide spectrum of symptoms ranging from intellectual and learning disabilities to behavioural challenges including autism spectrum disorder. In addition to this, patients also display a diversity of symptoms due to mosaicism. These factors make fragile X syndrome a difficult syndrome to manage and suggest that a single targeted therapeutic approach cannot address all the symptoms. To this end, we utilized Healx's data-driven drug discovery platform to identify a treatment strategy to address the wide range of diverse symptoms among patients. Computational methods identified the combination of ibudilast and gaboxadol as a treatment for several pathophysiological targets that could potentially reverse multiple symptoms associated with fragile X syndrome. Ibudilast is an approved broad-spectrum phosphodiesterase inhibitor, selective against both phosphodiesterase 4 and phosphodiesterase 10, and has demonstrated to have several beneficial effects in the brain. Gaboxadol is a GABAA receptor agonist, selective against the delta subunit, which has previously displayed encouraging results in a fragile X syndrome clinical trial. Alterations in GABA and cyclic adenosine monophosphate metabolism have long since been associated with the pathophysiology of fragile X syndrome; however, targeting both pathways simultaneously has never been investigated. Both drugs have a good safety and tolerability profile in the clinic making them attractive candidates for repurposing. We set out to explore whether the combination of ibudilast and gaboxadol could demonstrate therapeutic efficacy in a fragile X syndrome mouse model. We found that daily treatment with ibudilast significantly enhanced the ability of fragile X syndrome mice to perform a number of different cognitive assays while gaboxadol treatment improved behaviours such as hyperactivity, aggression, stereotypy and anxiety. Importantly, when ibudilast and gaboxadol were co-administered, the cognitive deficits as well as the aforementioned behaviours were rescued. Moreover, this combination treatment showed no evidence of tolerance, and no adverse effects were reported following chronic dosing. This work demonstrates for the first time that by targeting multiple pathways, with a combination treatment, we were able to rescue more phenotypes in a fragile X syndrome mouse model than either ibudilast or gaboxadol could achieve as monotherapies. This combination treatment approach holds promise for addressing the wide spectrum of diverse symptoms in this heterogeneous patient population and may have therapeutic potential for idiopathic autism.

Structure-Based Exploration of Selectivity for ATM Inhibitors in Huntington's Disease.

Our group has recently shown that brain-penetrant ataxia telangiectasia-mutated (ATM) kinase inhibitors may have potential as novel therapeutics for the treatment of Huntington's disease (HD). However, the previously described pyranone-thioxanthenes (e.g., 4) failed to afford selectivity over a vacuolar protein sorting 34 (Vps34) kinase, an important kinase involved with autophagy. Given that impaired autophagy has been proposed as a pathogenic mechanism of neurodegenerative diseases such as HD, achieving selectivity over Vps34 became an important objective for our program. Here, we report the successful selectivity optimization of ATM over Vps34 by using X-ray crystal structures of a Vps34-ATM protein chimera where the Vps34 ATP-binding site was mutated to approximate that of an ATM kinase. The morpholino-pyridone and morpholino-pyrimidinone series that resulted as a consequence of this selectivity optimization process have high ATM potency and good oral bioavailability and have lower molecular weight, reduced lipophilicity, higher aqueous solubility, and greater synthetic tractability compared to the pyranone-thioxanthenes.

Optimization of Potent and Selective Ataxia Telangiectasia-Mutated Inhibitors Suitable for a Proof-of-Concept Study in Huntington's Disease Models.

Genetic and pharmacological evidence indicates that the reduction of ataxia telangiectasia-mutated (ATM) kinase activity can ameliorate mutant huntingtin (mHTT) toxicity in cellular and animal models of Huntington's disease (HD), suggesting that selective inhibition of ATM could provide a novel clinical intervention to treat HD. Here, we describe the development and characterization of ATM inhibitor molecules to enable in vivo proof-of-concept studies in HD animal models. Starting from previously reported ATM inhibitors, we aimed with few modifications to increase brain exposure by decreasing P-glycoprotein liability while maintaining potency and selectivity. Here, we report brain-penetrant ATM inhibitors that have robust pharmacodynamic (PD) effects consistent with ATM kinase inhibition in the mouse brain and an understandable pharmacokinetic/PD (PK/PD) relationship. Compound 17 engages ATM kinase and shows robust dose-dependent inhibition of X-ray irradiation-induced KAP1 phosphorylation in the mouse brain. Furthermore, compound 17 protects against mHTT (Q73)-induced cytotoxicity in a cortical-striatal cell model of HD.

Supervivencia de vibrio cholerae O1 en hielo / Survival of vibrio cholerae O1 in ice

El hielo fue el vehículo de transmisión del cólera en uno de los peores brotes ocurridos en Latinoamerica en la última década, El presente estudio tuvo como objeto evaluar la supervivencia del Vibrio cholerae O1 en 20 muestras de hielo comercial almacenadas a -5ºC y -20ºC. La calidad microbiológica del hielo se determinó mediante el recuento de microorganismos aerobios mesófilos, coliformes totales, coliformes fecales y detección de V.cholerae O1. Para estudiar la supervivencia de V.cholerae O1 en hielo, poblaciones de 10 elevado a 9 ufc/ml de este microorganismo fueron inoculadas en muestras de hielo previamente descongeladas y sometidas a un proceso de congelación rápida y almacenamiento a -5ºC y -20ºC. La enumeración de las células sobrevivientes de V.cholerae O1 se realizó mediante la técnica del número más probable (NMP) usando agua peptonada alcalina como caldo de enriquecimiento, estriado en agar tiosulfato-citrato-sales biliares-sacarosa (TCBS) y confirmación de las colonias típicas mediante pruebas bioquímicas y serológicas. La población inoculada se redujo entre 6 y 7 ciclos logarítmicos después de 21 , días de almacenamiento en congelación y la eliminación total de células viables se produjo a los 30 días, siendo el proceso de congelación a -5ºC la causa de muerte del mayor número de células de Vibrio cholerae O1 (p<0,05). Por razón el consumo de hielo elaborado sin las medidas sanitarias adecuadas representa un riesgo para la transmisión del cólera, sobre todo cuando se utilizan temperaturas de -20ºC durante el proceso de congelación