Effects of novel fragment-warhead adducts in situ and in vitro with glutaredoxin orthologs.

Fragment-based drug design (FBDD) is a method of pharmaceutical research involving characterization of small “fragment” molecule interactions with a target protein. These fragments are optimized with the addition of a nucleophilic “warhead” moiety. Several novel fragment-warhead adducts have been synthesized in house by group member Ram Khattri Ph.D. The experiment investigates reactivity of these adducts with glutaredoxin protein (Grx) orthologs from Homo sapiens, Pseudomonas aeruginosa and Brucella melitensis. Three novel fragment-warhead adducts have been identified to cause weakly bacteriostatic and bacteriocidal effects, most with minimum inhibitory concentration values near 1.28 mg/mL. Discussed herein are molecular effects of these fragment-warhead compounds on Grx, such as their association in inducing Grx oligomerization. Further investigation of the fragment-warhead adduct coumarin acrylamide was performed due to its fluorescent properties. Use of Grx as a druggable candidate for development of a putative antibiotic has been a relatively untapped target until recently. These results may help further characterize Grx, and its ability to mediate bacterial survivability, to aid in the fight against multi-drug resistant and opportunistic bacterial infections such as pneumonia and brucellosis

Magnetic resonance-guided focused ultrasound treatment for essential tremor shows sustained efficacy: a meta-analysis

Although magnetic resonance-guided focused ultrasound (MRgFUS) is a viable treatment option for essential tremor, some studies note a diminished treatment benefit over time. A PubMed search was performed adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were included if hand tremor scores (HTS), total Clinical Rating Scale for Tremor (CRST) scores, or Quality of Life in Essential Tremor Questionnaire (QUEST) scores at regular intervals following MRgFUS treatment for essential tremor were documented. Data analyses included a random effects model of meta-analysis and mixed-effects model of meta-regression. Twenty-one articles reporting HTS for 395 patients were included. Mean pre-operative HTS was 19.2 ± 5.0. Mean HTS at 3 months post-treatment was 7.4 ± 5.0 (61.5% improvement, p \u3c 0.001). Treatment effect was mildly decreased at 36 months at 9.1 ± 5.4 (8.8% reduction). Meta-regression of time since treatment as a modifier of HTS revealed a downward trend in effect size, though this was not statistically significant (p = 0.208). Only 4 studies included follow-up ≥ 24 months. Thirteen included articles reported total CRST scores with standardized follow-up for 250 patients. Mean pre-operative total CRST score decreased by 46.2% at 3 months post-treatment (p \u3c 0.001). Additionally, mean QUEST scores at 3 months post-treatment significantly improved compared to baseline (p \u3c 0.001). HTS is significantly improved from baseline ≥ 24 months post-treatment and possibly ≥ 48 months post-treatment. There is a current paucity of long-term CRST and QUEST score reporting in the literature

An NMR-Guided Screening Method for Selective Fragment Docking and Synthesis of a Warhead Inhibitor

Selective hits for the glutaredoxin ortholog of Brucella melitensis are determined using STD NMR and verified by trNOE and (15)N-HSQC titration. The most promising hit, RK207, was docked into the target molecule using a scoring function to compare simulated poses to experimental data. After elucidating possible poses, the hit was further optimized into the lead compound by extension with an electrophilic acrylamide warhead. We believe that focusing on selectivity in this early stage of drug discovery will limit cross-reactivity that might occur with the human ortholog as the lead compound is optimized. Kinetics studies revealed that lead compound 5 modified with an ester group results in higher reactivity than an acrylamide control; however, after modification this compound shows little selectivity for bacterial protein versus the human ortholog. In contrast, hydrolysis of compound 5 to the acid form results in a decrease in the activity of the compound. Together these results suggest that more optimization is warranted for this simple chemical scaffold, and opens the door for discovery of drugs targeted against glutaredoxin proteins-a heretofore untapped reservoir for antibiotic agents

An NMR-Guided Screening Method for Selective Fragment Docking and Synthesis of a Warhead Inhibitor

Selective hits for the glutaredoxin ortholog of Brucella melitensis are determined using STD NMR and verified by trNOE and 15N-HSQC titration. The most promising hit, RK207, was docked into the target molecule using a scoring function to compare simulated poses to experimental data. After elucidating possible poses, the hit was further optimized into the lead compound by extension with an electrophilic acrylamide warhead. We believe that focusing on selectivity in this early stage of drug discovery will limit cross-reactivity that might occur with the human ortholog as the lead compound is optimized. Kinetics studies revealed that lead compound 5 modified with an ester group results in higher reactivity than an acrylamide control; however, after modification this compound shows little selectivity for bacterial protein versus the human ortholog. In contrast, hydrolysis of compound 5 to the acid form results in a decrease in the activity of the compound. Together these results suggest that more optimization is warranted for this simple chemical scaffold, and opens the door for discovery of drugs targeted against glutaredoxin proteins—a heretofore untapped reservoir for antibiotic agents