ent-Verticilide B1 Inhibits Type 2 Ryanodine Receptor Channels and is Antiarrhythmic in Casq2 -/- Mice.

Intracellular Ca2+ leak from cardiac ryanodine receptor (RyR2) is an established mechanism of sudden cardiac death (SCD), whereby dysregulated Ca2+ handling causes ventricular arrhythmias. We previously discovered the RyR2-selective inhibitor ent-(+)-verticilide (ent-1), a 24-membered cyclooligomeric depsipeptide that is the enantiomeric form of a natural product (nat-(-)-verticilide). Here, we examined its 18-membered ring-size oligomer (ent-verticilide B1; "ent-B1") in RyR2 single channel and [3H]ryanodine binding assays, and in Casq2 -/- cardiomyocytes and mice, a gene-targeted model of SCD. ent-B1 inhibited RyR2 single channels and RyR2-mediated spontaneous Ca2+ release in Casq2 -/- cardiomyocytes with sub-micromolar potency. ent-B1 was a partial RyR2 inhibitor, with maximal inhibitory efficacy of less than 50%. ent-B1 was stable in plasma, with a peak plasma concentration of 1460 ng/ml at 10 minutes and half-life of 45 minutes after intraperitoneal administration of 3 mg/kg in mice. In vivo, ent-B1 significantly reduced catecholamine-induced ventricular arrhythmias in Casq2 -/- mice in a dose-dependent manner. Hence, we have identified a novel chemical entity - ent-B1 - that preserves the mechanism of action of a hit compound and shows therapeutic efficacy. These findings strengthen RyR2 as an antiarrhythmic drug target and highlight the potential of investigating the mirror-image isomers of natural products to discover new therapeutics. SIGNIFICANCE STATEMENT: The cardiac ryanodine receptor (RyR2) is an untapped target in the stagnant field of antiarrhythmic drug development. We have confirmed RyR2 as an antiarrhythmic target in a mouse model of sudden cardiac death and shown the therapeutic efficacy of a second enantiomeric natural product.

Optimized arylomycins are a new class of Gram-negative antibiotics.

Multidrug-resistant bacteria are spreading at alarming rates, and despite extensive efforts no new class of antibiotic with activity against Gram-negative bacteria has been approved in over fifty years. Natural products and their derivatives have a key role in combating Gram-negative pathogens. Here we report chemical optimization of the arylomycins-a class of natural products with weak activity and limited spectrum-to obtain G0775, a molecule with potent, broad-spectrum activity against Gram-negative bacteria. G0775 inhibits the essential bacterial type I signal peptidase, a new antibiotic target, through an unprecedented molecular mechanism. It circumvents existing antibiotic resistance mechanisms and retains activity against contemporary multidrug-resistant Gram-negative clinical isolates in vitro and in several in vivo infection models. These findings demonstrate that optimized arylomycin analogues such as G0775 could translate into new therapies to address the growing threat of multidrug-resistant Gram-negative infections.

Cardiac ryanodine receptor N-terminal region biosensors identify novel inhibitors via FRET-based high-throughput screening.

The N-terminal region (NTR) of ryanodine receptor (RyR) channels is critical for the regulation of Ca2+ release during excitation-contraction (EC) coupling in muscle. The NTR hosts numerous mutations linked to skeletal (RyR1) and cardiac (RyR2) myopathies, highlighting its potential as a therapeutic target. Here, we constructed two biosensors by labeling the mouse RyR2 NTR at domains A, B, and C with FRET pairs. Using fluorescence lifetime (FLT) detection of intramolecular FRET signal, we developed high-throughput screening (HTS) assays with these biosensors to identify small-molecule RyR modulators. We then screened a small validation library and identified several hits. Hits with saturable FRET dose-response profiles and previously unreported effects on RyR were further tested using [3H]ryanodine binding to isolated sarcoplasmic reticulum vesicles to determine effects on intact RyR opening in its natural membrane. We identified three novel inhibitors of both RyR1 and RyR2 and two RyR1-selective inhibitors effective at nanomolar Ca2+. Two of these hits activated RyR1 only at micromolar Ca2+, highlighting them as potential enhancers of excitation-contraction coupling. To determine whether such hits can inhibit RyR leak in muscle, we further focused on one, an FDA-approved natural antibiotic, fusidic acid (FA). In skinned skeletal myofibers and permeabilized cardiomyocytes, FA inhibited RyR leak with no detrimental effect on skeletal myofiber excitation-contraction coupling. However, in intact cardiomyocytes, FA induced arrhythmogenic Ca2+ transients, a cautionary observation for a compound with an otherwise solid safety record. These results indicate that HTS campaigns using the NTR biosensor can identify compounds with therapeutic potential.

Brain-penetrant cyanoindane and cyanotetralin inhibitors of G2019S-LRRK2 kinase activity.

The G2019S variant of LRRK2, which causes an increase in kinase activity, is associated with the occurrence of Parkinson's disease (PD). Potent, mutation-selective, and brain penetrant inhibitors of LRRK2 can suppress the biological effects specific to G2019S-LRRK2 that cause pathogenicity. We report the discovery of a series of cyanoindane and cyanotetralin kinase inhibitors culminating in compound 34 that demonstrated selective inhibition of phosphorylation of LRRK2 in the mouse brain. These novel inhibitors may further enable the precision medicine path for future PD therapeutics.

Leveraging web-based prediction calculators to set patient expectations for elective spine surgery: a qualitative study to inform implementation.

BACKGROUND: Prediction calculators can help set outcomes expectations following orthopaedic surgery, however effective implementation strategies for these tools are unknown. This study evaluated provider and patient perspectives on clinical implementation of web-based prediction calculators developed using national prospective spine surgery registry data from the Quality Outcomes Database. METHODS: We conducted semi-structured interviews in two health systems, Vanderbilt University Medical Center (VUMC) and Duke University Health System (DUHS) of orthopedic and neurosurgery health care providers (VUMC: n = 19; DUHS: n = 6), health care administrators (VUMC: n = 9; DUHS: n = 9), and patients undergoing elective spine surgery (VUMC: n = 16). Qualitative template analysis was used to analyze interview data, with a focus on end-user perspectives regarding clinical implementation of web-based prediction tools. RESULTS: Health care providers, administrators and patients overwhelmingly supported the use of the calculators to help set realistic expectations for surgical outcomes. Some clinicians had questions about the validity and applicability of the calculators in their patient population. A consensus was that the calculators needed seamless integration into clinical workflows, but there was little agreement on best methods for selecting which patients to complete the calculators, timing, and mode of completion. Many interviewees expressed concerns that calculator results could influence payers, or expose risk of liability. Few patients expressed concerns over additional survey burden if they understood that the information would directly inform their care. CONCLUSIONS: Interviewees had a largely positive opinion of the calculators, believing they could aid in discussions about expectations for pain and functional recovery after spine surgery. No single implementation strategy is likely to be successful, and strategies vary, even within the same healthcare system. Patients should be well-informed of how responses will be used to deliver better care, and concerns over how the calculators could impact payment and liability should be addressed prior to use. Future research is necessary to determine whether use of calculators improves management and outcomes for people seeking a surgical consult for spine pain.

Discovery of 5,6,7,8-tetrahydropyrido[3,4-d]pyrimidine inhibitors of Erk2.

The discovery and optimization of a series of tetrahydropyridopyrimidine based extracellular signal-regulated kinase (Erks) inhibitors discovered via HTS and structure based drug design is reported. The compounds demonstrate potent and selective inhibition of Erk2 and knockdown of phospho-RSK levels in HepG2 cells and tumor xenografts.

Combining Wearable Technology and Telehealth Counseling for Rehabilitation After Lumbar Spine Surgery: Feasibility and Acceptability of a Physical Activity Intervention.

OBJECTIVE: The purpose of this study was to examine the feasibility and acceptability of a wearable device and telehealth counseling physical activity intervention early after lumbar spine surgery. METHODS: Sixteen patients were randomized to an 8-session physical activity intervention or to usual postoperative care after surgery. The intervention included a wearable device (ie, Fitbit) and telehealth counseling by a licensed physical therapist. The feasibility of study procedures was assessed through recruitment, randomization, retention, and participation rates. Acceptability was assessed through a satisfaction survey and median within-participant change in objective physical activity (steps per day and time spent in moderate-to-vigorous physical activity [MVPA]) and patient-reported outcomes. RESULTS: Of 64 participants who were eligible, recruitment and randomization rates were 41 and 62%, respectively. Retention for objective physical activity and patient-reported outcomes was 94 and 100%, respectively, at 6-month follow-up. Seven (88%) participants in the intervention group completed all telehealth sessions, and 6 (75%) met step goals over the 8 sessions. All participants in the intervention group found the wearable device and telehealth counseling to be helpful and reported it much or somewhat more important than other postoperative services. Median within-participant change for steps per day improved from baseline (preoperative) to 6 months after surgery for both the intervention (1070) and usual care (679) groups, while MVPA only improved for the intervention group (2.2. minutes per day). Improvements in back and leg pain and disability were noted for both groups. No adverse events were reported in the study. CONCLUSION: Combining wearable technology and telehealth counseling is a feasible approach to promote the physical activity during the early postoperative period after spine surgery. Future randomized controlled trials are needed to investigate the efficacy of leveraging wearables and telehealth during postoperative rehabilitation. IMPACT: This study has implications for the clinical dissemination of physical activity strategies in the rehabilitation setting.

Safety of early discharge after elective lumbar spine surgery with subfascial drains and association with significant reduction in length of stay.

OBJECTIVE: After lumbar spine surgery, postoperative drain removal often delays discharge. Whether inpatient drain removal reduces the risk of surgical site infection (SSI) or hematoma remains controversial. Therefore, in patients undergoing elective lumbar spine surgery, the authors sought to determine the impact of inpatient versus outpatient drain removal on the following variables: 1) length of hospital stay (LOS), and 2) postoperative complications. METHODS: A single-center retrospective cohort study in which the authors used prospectively collected data of patients undergoing primary, elective, 1- or 2-level lumbar spine decompression and/or fusion was undertaken between 2016 and 2022. Patients with intraoperative or postoperative CSF leaks were excluded. The primary exposure variable was inpatient versus outpatient drain removal. The primary outcome was LOS, and secondary outcomes were postoperative complications, including 90-day postoperative SSI or hematoma. Multivariable logistic and linear regression were performed, controlling for age, body mass index, instrumentation, number of levels, antibiotics at discharge, and surgeons involved. RESULTS: Of 483 patients included, 325 (67.3%) had inpatient drain removal and 158 (32.7%) had outpatient drain removal. Patients with outpatient drain removal were significantly younger (58.6 ± 12.4 vs 61.2 ± 13.2 years, p = 0.040); more likely to have 1-level surgery (75.9% vs 56.6%, p < 0.001); and less likely to receive instrumentation (50.6% vs 69.5%, p < 0.001). Postoperatively, patients with outpatient drain removal had a shorter LOS (0.7 ± 0.6 vs 2.3 ± 1.6 days, p < 0.001); were more likely to be discharged home (98.1% vs 92.3%, p = 0.015); were more likely to be discharged on antibiotics (76.6% vs 3.1%, p < 0.001); were less likely to be on opioids (32.3% vs 88.3%, p < 0.001); and were more likely to have Jackson-Pratt compared to Hemovac drains (96.2% vs 34.5%, p < 0.001). No difference was found in SSI (3.7% vs 3.8%, p > 0.999) or hematoma (0.9% vs 0.6%, p > 0.999), as well as reoperation or readmission due to SSI or hematoma. On multivariable regression, outpatient drain removal was significantly associated with shorter LOS (ß = -1.15, 95% CI -1.56 to -0.73, p < 0.001). No association was found with SSI/hematoma (p > 0.05). CONCLUSIONS: Outpatient drain removal after elective lumbar spine surgery was associated with a significantly decreased LOS without a significant increase in postoperative SSI or hematoma. Although the choice of drain removal and the LOS may be subject to surgeons' preference, these results may support the feasibility and safety of outpatient drain removal, and the potential cost savings resulting from shortened hospital stays. Drawbacks may exist regarding added burden to the patient and the surgeon's team to accommodate 1-week follow-up appointments for drain removal.

Discovery of Potent, Selective, and Orally Available IRE1α Inhibitors Demonstrating Comparable PD Modulation to IRE1 Knockdown in a Multiple Myeloma Model.

The lack of selective and safe in vivo IRE1α tool molecules has limited the evaluation of IRE1α as a viable target to treat multiple myeloma. Focus on improving the physicochemical properties of a literature compound by decreasing lipophilicity, molecular weight, and basicity allowed the discovery of a novel series with a favorable in vitro safety profile and good oral exposure. These efforts culminated in the identification of a potent and selective in vivo tool compound, G-5758, that was well tolerated following multiday oral administration of doses up to 500 mg/kg. G-5758 demonstrated comparable pharmacodynamic effects to induced IRE1 knockdown as measured by XBP1s levels in a multiple myeloma model (KMS-11).

ent -Verticilide B1 inhibits type 2 ryanodine receptor channels and is antiarrhythmic in Casq2-/- mice.

Ca 2+ leak from cardiac ryanodine receptor (RyR2) is an established mechanism of sudden cardiac death (SCD), whereby dysregulated Ca 2+ handling causes ventricular arrhythmias. We previously discovered the RyR2-selective inhibitor ent- (+)-verticilide ( ent -1), a 24-membered cyclooligomeric depsipeptide that is the enantiomeric form of a natural product ( nat -(-)-verticilide). Here, we examined its 18-membered ring-size oligomer ( ent -verticilide B1; " ent -B1") in single RyR2 channel assays, [ 3 H]ryanodine binding assays, and in Casq2 -/- cardiomyocytes and mice, a gene-targeted model of SCD. ent -B1 inhibited RyR2 single-channels and [ 3 H]ryanodine binding with low micromolar potency, and RyR2-mediated spontaneous Ca 2+ release in Casq2-/- cardiomyocytes with sub-micromolar potency. ent -B1 was a partial RyR2 inhibitor, with maximal inhibitory efficacy of less than 50%. ent -B1 was stable in plasma, with a peak plasma concentration of 1460 ng/ml at 10 min and half-life of 45 min after intraperitoneal administration of 3 mg/kg in mice. Both 3 mg/kg and 30 mg/kg ent -B1 significantly reduced catecholamine-induced ventricular arrhythmia in Casq2-/- mice. Hence, we have identified a novel chemical entity - ent -B1 - that preserves the mechanism of action of a hit compound and shows therapeutic efficacy. These findings strengthen RyR2 as an antiarrhythmic drug target and highlight the potential of investigating the mirror-image isomers of natural products to discover new therapeutics. Significance statement: The cardiac ryanodine receptor (RyR2) is an untapped target in the stagnant field of antiarrhythmic drug development. We have confirmed RyR2 as an antiarrhythmic target in a mouse model of sudden cardiac death and shown the therapeutic efficacy of a second enantiomeric natural product.

Assessment of safety and effectiveness of non-neurosurgical management for minimal traumatic brain injury (TBI).

BACKGROUND: Patients with mild traumatic brain injury (TBI) and intracranial hemorrhage often receive neurosurgical consultation. However, only a small proportion of patients require intervention. Our hypothesis is that low-risk minimal TBI patients managed without immediate neurosurgical consultation will have a reasonable safety and effectiveness outcome profile. METHODS: A non-neurosurgical management protocol for adult minimal TBI was implemented at a level I trauma center as an interdisciplinary quality-improvement initiative in November 2018. Minimal TBI was defined as Glasgow Coma Scale (GCS) of 15 secondary to blunt mechanism, without anticoagulant or antiplatelet therapy, and isolated pneumocephalus and/or traumatic subarachnoid hemorrhage on head CT imaging. Safety was assessed by in-hospital mortality, neurosurgical interventions, and ED revisits within two weeks of discharge. Effectiveness was assessed by neurosurgical consult rate and length of stay. Outcomes were compared 8-months pre- and post-protocol implementation. RESULTS: A total of 97 patients were included, of which 49 were pre-protocol and 48 were post-protocol There was no difference in rates of in-hospital mortality [0 (0%) vs 0 (0%)], neurosurgical procedure [1 (2.1%) vs 0 (0%)], operations [0 (0%) vs 0 (0%)], and ED revisits [1 (2.0%) vs 2 (4.2%), p = 0.985] between the periods. There was a significant reduction in neurosurgical consults post-protocol implementation (92% vs 29%, p<0.001). CONCLUSION: A protocol for minimal TBI patients effectively reduced neurosurgical consultation without changes in safety profile. Such an interdisciplinary management protocol for low-risk neurotrauma can effectively utilize the neurosurgery consult services by stratifying neurologically stable TBI patient.

RyR2 Binding of an Antiarrhythmic Cyclic Depsipeptide Mapped Using Confocal Fluorescence Lifetime Detection of FRET.

Hyperactivity of cardiac sarcoplasmic reticulum (SR) ryanodine receptor (RyR2) Ca2+-release channels contributes to heart failure and arrhythmias. Reducing the RyR2 activity, particularly during cardiac relaxation (diastole), is a desirable therapeutic goal. We previously reported that the unnatural enantiomer (ent) of an insect-RyR activator, verticilide, inhibits porcine and mouse RyR2 at diastolic (nanomolar) Ca2+ and has in vivo efficacy against atrial and ventricular arrhythmia. To determine the ent-verticilide structural mode of action on RyR2 and guide its further development via medicinal chemistry structure-activity relationship studies, here, we used fluorescence lifetime (FLT)-measurements of Förster resonance energy transfer (FRET) in HEK293 cells expressing human RyR2. For these studies, we used an RyR-specific FRET molecular-toolkit and computational methods for trilateration (i.e., using distances to locate a point of interest). Multiexponential analysis of FLT-FRET measurements between four donor-labeled FKBP12.6 variants and acceptor-labeled ent-verticilide yielded distance relationships placing the acceptor probe at two candidate loci within the RyR2 cryo-EM map. One locus is within the Ry12 domain (at the corner periphery of the RyR2 tetrameric complex). The other locus is sandwiched at the interface between helical domain 1 and the SPRY3 domain. These findings document RyR2-target engagement by ent-verticilide, reveal new insight into the mechanism of action of this new class of RyR2-targeting drug candidate, and can serve as input in future computational determinations of the ent-verticilide binding site on RyR2 that will inform structure-activity studies for lead optimization.

Lipid Tales: Optimizing Arylomycin Membrane Anchors.

Multidrug-resistant bacteria are spreading at alarming rates, and despite extensive efforts, no new antibiotic class with activity against Gram-negative bacteria has been approved in over 50 years. LepB inhibitors (LepBi) based on the arylomycin class of natural products are a novel class of antibiotics and function by inhibiting the bacterial type I signal peptidase (SPase) in Gram-negative bacteria. One critical aspect of LepBi development involves optimization of the membrane-anchored lipophilic portion of the molecule. We therefore developed an approach that assesses the effect of this portion on the complicated equilibria of plasma protein binding, crossing the outer membrane of Gram-negative bacteria and anchoring in the bacterial inner membrane to facilitate SPase binding. Our findings provide important insights into the development of antibacterial agents where the target is associated with the inner membrane of Gram-negative bacteria.

Potent GCN2 Inhibitor Capable of Reversing MDSC-Driven T Cell Suppression Demonstrates In Vivo Efficacy as a Single Agent and in Combination with Anti-Angiogenesis Therapy.

General control nonderepressible 2 (GCN2) protein kinase is a cellular stress sensor within the tumor microenvironment (TME), whose signaling cascade has been proposed to contribute to immune escape in tumors. Herein, we report the discovery of cell-potent GCN2 inhibitors with excellent selectivity against its closely related Integrated Stress Response (ISR) family members heme-regulated inhibitor kinase (HRI), protein kinase R (PKR), and (PKR)-like endoplasmic reticulum kinase (PERK), as well as good kinome-wide selectivity and favorable PK. In mice, compound 39 engages GCN2 at levels ≥80% with an oral dose of 15 mg/kg BID. We also demonstrate the ability of compound 39 to alleviate MDSC-related T cell suppression and restore T cell proliferation, similar to the effect seen in MDSCs from GCN2 knockout mice. In the LL2 syngeneic mouse model, compound 39 demonstrates significant tumor growth inhibition (TGI) as a single agent. Furthermore, TGI mediated by anti-VEGFR was enhanced by treatment with compound 39 demonstrating the complementarity of these two mechanisms.

High-throughput screening in embryonic stem cell-derived neurons identifies potentiators of alpha-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate-type glutamate receptors.

Stem cell biology offers advantages to investigators seeking to identify new therapeutic molecules. Specifically, stem cells are genetically stable, scalable for molecular screening, and function in cellular assays for drug efficacy and safety. A key hurdle for drug discoverers of central nervous system disease is a lack of high quality neuronal cells. In the central nervous system, alpha-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate (AMPA) subtype glutamate receptors mediate the vast majority of excitatory neurotransmissions. Embryonic stem (ES) cell protocols were developed to differentiate into neuronal subtypes that express AMPA receptors and were pharmacologically responsive to standard compounds for AMPA potentiation. Therefore, we hypothesized that stem cell-derived neurons should be predictive in high-throughput screens (HTSs). Here, we describe a murine ES cell-based HTS of a 2.4 x 10(6) compound library, the identification of novel chemical "hits" for AMPA potentiation, structure function relationship of compounds and receptors, and validation of chemical leads in secondary assays using human ES cell-derived neurons. This reporting of murine ES cell derivatives being formatted to deliver HTS of greater than 10(6) compounds for a specific drug target conclusively demonstrates a new application for stem cells in drug discovery. In the future new molecular entities may be screened directly in human ES or induced pluripotent stem cell derivatives.

Early Self-directed Home Exercise Program After Anterior Cervical Discectomy and Fusion: A Pilot Study.

STUDY DESIGN: Pilot randomized controlled trial. OBJECTIVE: To examine the acceptability and preliminary safety and outcome effects of an early self-directed home exercise program (HEP) performed within the first 6 weeks after anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Little is known regarding optimal postoperative management after ACDF. METHODS: Thirty patients (mean ±â€Šstandard deviation, age = 50.6 ±â€Š11.0 years, 16 women) undergoing ACDF were randomized to receive an early HEP (n = 15) or usual care (n = 15). The early HEP was a 6-week self-directed program with weekly supportive telephone calls to reduce pain and improve activity. Treatment acceptability was assessed after the intervention period (6 weeks after surgery). Safety (adverse events, radiographic fusion, revision surgery) was determined at routine postoperative visits. Disability (Neck Disability Index), pain intensity (Numeric Rating Scale for neck and arm pain), physical and mental health (SF-12), and opioid use were assessed preoperatively, and at 6 weeks and 6 and 12 months after surgery by an evaluator blinded to group assignment. RESULTS: Participants reported high levels of acceptability and no serious adverse events with the early HEP. No difference in fusion rate was observed between groups (P > 0.05) and no participants underwent revision surgery. The early self-directed HEP group reported lower 6-week neck pain than the usual care group (F = 3.3, P = 0.04, r = 0.3, mean difference = -1.7 [-3.4; -0.05]) and lower proportion of individuals (13% vs. 47%) using opioids at 12 months (P = 0.05). No other between-group outcome differences were observed (P > 0.05). CONCLUSION: An early self-directed HEP program was acceptable to patients and has the potential to be safely administered to patients immediately after ACDF. Benefits were noted for short-term neck pain and long-term opioid utilization. However, larger trials are needed to confirm safety with standardized and long-term radiograph assessment and treatment efficacy. LEVEL OF EVIDENCE: 2.

Identification of BRaf-Sparing Amino-Thienopyrimidines with Potent IRE1α Inhibitory Activity.

Amino-quinazoline BRaf kinase inhibitor 2 was identified from a library screen as a modest inhibitor of the unfolded protein response (UPR) regulating potential anticancer target IRE1α. A combination of crystallographic and conformational considerations were used to guide structure-based attenuation of BRaf activity and optimization of IRE1α potency. Quinazoline 6-position modifications were found to provide up to 100-fold improvement in IRE1α cellular potency but were ineffective at reducing BRaf activity. A salt bridge contact with Glu651 in IRE1α was then targeted to build in selectivity over BRaf which instead possesses a histidine in this position (His539). Torsional angle analysis revealed that the quinazoline hinge binder core was ill-suited to accommodate the required conformation to effectively reach Glu651, prompting a change to the thienopyrimidine hinge binder. Resulting analogues such as 25 demonstrated good IRE1α cellular potency and imparted more than 1000-fold decrease in BRaf activity.

Discovery of Potent, Selective, and Orally Bioavailable Inhibitors of USP7 with In Vivo Antitumor Activity.

USP7 is a promising target for cancer therapy as its inhibition is expected to decrease function of oncogenes, increase tumor suppressor function, and enhance immune function. Using a structure-based drug design strategy, a new class of reversible USP7 inhibitors has been identified that is highly potent in biochemical and cellular assays and extremely selective for USP7 over other deubiquitinases. The succinimide was identified as a key potency-driving motif, forming two strong hydrogen bonds to the allosteric pocket of USP7. Redesign of an initial benzofuran-amide scaffold yielded a simplified ether series of inhibitors, utilizing acyclic conformational control to achieve proper amine placement. Further improvements were realized upon replacing the ether-linked amines with carbon-linked morpholines, a modification motivated by free energy perturbation (FEP+) calculations. This led to the discovery of compound 41, a highly potent, selective, and orally bioavailable USP7 inhibitor. In xenograft studies, compound 41 demonstrated tumor growth inhibition in both p53 wildtype and p53 mutant cancer cell lines, demonstrating that USP7 inhibitors can suppress tumor growth through multiple different pathways.

Novel, Selective Inhibitors of USP7 Uncover Multiple Mechanisms of Antitumor Activity In Vitro and In Vivo.

The deubiquitinase USP7 regulates the levels of multiple proteins with roles in cancer progression and immune response. Thus, USP7 inhibition may decrease oncogene function, increase tumor suppressor function, and sensitize tumors to DNA-damaging agents. We have discovered a novel chemical series that potently and selectively inhibits USP7 in biochemical and cellular assays. Our inhibitors reduce the viability of multiple TP53 wild-type cell lines, including several hematologic cancer and MYCN-amplified neuroblastoma cell lines, as well as a subset of TP53-mutant cell lines in vitro Our work suggests that USP7 inhibitors upregulate transcription of genes normally silenced by the epigenetic repressor complex, polycomb repressive complex 2 (PRC2), and potentiate the activity of PIM and PI3K inhibitors as well as DNA-damaging agents. Furthermore, oral administration of USP7 inhibitors inhibits MM.1S (multiple myeloma; TP53 wild type) and H526 (small cell lung cancer; TP53 mutant) tumor growth in vivo Our work confirms that USP7 is a promising, pharmacologically tractable target for the treatment of cancer.

GluN2A NMDA Receptor Enhancement Improves Brain Oscillations, Synchrony, and Cognitive Functions in Dravet Syndrome and Alzheimer's Disease Models.

NMDA receptors (NMDARs) play subunit-specific roles in synaptic function and are implicated in neuropsychiatric and neurodegenerative disorders. However, the in vivo consequences and therapeutic potential of pharmacologically enhancing NMDAR function via allosteric modulation are largely unknown. We examine the in vivo effects of GNE-0723, a positive allosteric modulator of GluN2A-subunit-containing NMDARs, on brain network and cognitive functions in mouse models of Dravet syndrome (DS) and Alzheimer's disease (AD). GNE-0723 use dependently potentiates synaptic NMDA receptor currents and reduces brain oscillation power with a predominant effect on low-frequency (12-20 Hz) oscillations. Interestingly, DS and AD mouse models display aberrant low-frequency oscillatory power that is tightly correlated with network hypersynchrony. GNE-0723 treatment reduces aberrant low-frequency oscillations and epileptiform discharges and improves cognitive functions in DS and AD mouse models. GluN2A-subunit-containing NMDAR enhancers may have therapeutic benefits in brain disorders with network hypersynchrony and cognitive impairments.