Evaluating protein cross-linking as a therapeutic strategy to stabilize SOD1 variants in a mouse model of familial ALS

Computational Search for Inhibitors of SOD1 Mutant Infectivity as Potential Therapeutics for ALS Disease

Familial amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the selective degeneration of motor neurons. Among the main genetic causes of ALS, over 200 mutations have been identified in the Cu/Zn superoxide dismutase (SOD1) protein, a dimeric metalloenzyme essential for converting superoxides from cellular respiration into less toxic products. Point mutations in SOD1 monomers can induce protein misfolding, which spreads to wild-type monomers through a prion-like mechanism, leading to dysfunctions that contribute to the development of the disease. Understanding the structural and functional differences between the wild-type protein and its mutated variants, as well as developing drugs capable of inhibiting the propagation of misfolding, is crucial for identifying new therapeutic strategies. In this work, seven SOD1 mutations (A4V, G41D, G41S, D76V, G85R, G93A, and I104F) were selected, and three-dimensional models of SOD1 dimers composed of one wild-type monomer and one mutated monomer were generated, along with a control dimer consisting solely of wild-type monomers. Molecular dynamics simulations were conducted to investigate conformational differences between the dimers. Additionally, molecular docking was performed using a library of ligands to identify compounds with high affinity for the mutated dimers. The study reveals some differences in the mutated dimers following molecular dynamics simulations and in the docking of the selected ligands with the various dimers.

Rare Diseases, Spotlighting Amyotrophic Lateral Sclerosis, Huntington's Disease, and Myasthenia Gravis: Insights from Landscape Analysis of Current Research

Rare diseases are a diverse group of disorders that, despite each individual condition's rarity, collectively affect a significant portion of the global population. Currently approximately 10,000 rare diseases exist globally, with 80% of these diseases being identified as having genetic origins. In this Review, we examine data from the CAS Content Collection to summarize scientific progress in the area of rare diseases. We examine the publication landscape in the area in an effort to provide insights into current advances and developments. We then discuss the evolution of key concepts in the field, genetic associations, as well as the major technologies and development pipelines of rare disease treatments. We focus our attention on three specific rare diseases: (i) amyotrophic lateral sclerosis, a terminal neurodegenerative disease affecting the central nervous system resulting in progressive loss of motor neurons that control voluntary muscles; (ii) Huntington's disease, another terminal neurodegenerative disease that causes progressive degeneration of nerve cells in the brain, with a wide impact on a person's functional abilities; and (iii) myasthenia gravis, a chronic autoimmune synaptopathy leading to skeletal muscle weakness. While the pathogenesis of these rare diseases is being elucidated, there is neither a cure nor preventative treatment available, only symptomatic treatment. The objective of the paper is to provide a broad overview of the evolving landscape of current knowledge on rare diseases and specifically on the biology and genetics of the three spotlighted diseases, to outline challenges and evaluate growth opportunities, an aim to further efforts in solving the remaining challenges.

Mass spectrometry methods and mathematical PK/PD model for decision tree-guided covalent drug development

Covalent drug discovery efforts are growing rapidly but have major unaddressed limitations. These include high false positive rates during hit-to-lead identification; the inherent uncoupling of covalent drug concentration and effect [i.e., uncoupling of pharmacokinetics (PK) and pharmacodynamics (PD)]; and a lack of bioanalytical and modeling methods for determining PK and PD parameters. We present a covalent drug discovery workflow that addresses these limitations. Our bioanalytical methods are based upon a mass spectrometry (MS) assay that can measure the percentage of drug-target protein conjugation (% target engagement) in biological matrices. Further we develop an intact protein PK/PD model (iPK/PD) that outputs PK parameters (absorption and distribution) as well as PD parameters (mechanism of action, protein metabolic half-lives, dose, regimen, effect) based on time-dependent target engagement data. Notably, the iPK/PD model is applicable to any measurement (e.g., bottom-up MS and other drug binding studies) that yields % of target engaged. A Decision Tree is presented to guide researchers through the covalent drug development process. Our bioanalytical methods and the Decision Tree are applied to two approved drugs (ibrutinib and sotorasib); the most common plasma off-target, human serum albumin; three protein targets (KRAS, BTK, SOD1), and to a promising SOD1-targeting ALS drug candidates.

Pilot Trial of Perampanel on Peritumoral Hyperexcitability in Newly Diagnosed High-grade Glioma

PURPOSE

Glutamatergic neuron-glioma synaptogenesis and peritumoral hyperexcitability promote glioma growth in a positive feedback loop. The objective of this study was to evaluate the feasibility and estimated effect sizes of the targeted AMPA receptor antagonist perampanel on peritumoral hyperexcitability.

EXPERIMENTAL DESIGN

An open-label trial was performed comparing perampanel with standard of care (SOC) in patients undergoing resection of newly diagnosed radiologic high-grade glioma. Perampanel was administered as a preoperative loading dose followed by maintenance therapy until progressive disease or up to 12 months. SOC treatment involved levetiracetam for 7 days or as clinically indicated. The primary outcome of hyperexcitability was defined by intraoperative electrocorticography high-frequency oscillation (HFO) rates. Seizure freedom and overall survival were estimated by the Kaplan-Meier method. Tissue concentrations of perampanel, levetiracetam, and correlative biomarkers were measured by mass spectrometry.

RESULTS

HFO rates were similar between patients treated with perampanel and levetiracetam. The trial was terminated early after a planned interim analysis, and outcomes assessed in 11 patients (seven perampanel treated; four treated with SOC). Over a median 281 days of postenrollment follow-up, 27% of patients had seizures, including 14% maintained on perampanel and 50% treated with SOC. Overall survival in perampanel-treated patients was similar to that in a glioblastoma reference cohort. Glutamate concentrations in surface biopsies were positively correlated with HFO rates in adjacent electrode contacts and were not significantly associated with treatment assignment or drug concentrations.

CONCLUSIONS

Glioma peritumoral glutamate concentrations correlated with high-gamma oscillation rates. Targeting glutamatergic activity with perampanel achieved similar electrocorticographic hyperexcitability levels as in levetiracetam-treated patients.

Dysregulation of ceramide metabolism causes phytoceramide-dependent induction of the unfolded protein response

The unfolded protein response (UPR) detects and mitigates the harmful effects of dysregulated endoplasmic reticulum (ER) function. The UPR has been best characterized as a protein quality control response, and the sole UPR sensor in yeast, Ire1, is known to detect misfolded ER proteins. However, recent work suggests the UPR can also sense diverse defects within the ER membrane, including increased fatty acid saturation and altered phospholipid abundance. These and other lipid-related stimuli have been referred to as lipid bilayer stress and may be sensed independently through Ire1's transmembrane domain. Here, we show that the loss of Isc1, a phospholipase that catabolizes complex ceramides, causes UPR induction, even in the absence of exogenous stress. A series of chemical and genetic approaches identified a requirement for very long-chain fatty acid (VLCFA)-containing phytoceramides for UPR induction. In parallel, comprehensive lipidomics analyses identified large increases in the abundance of specific VLCFA-containing phytoceramides in the isc1Δ mutant. We failed to identify evidence of an accompanying defect in protein quality control or ER-associated protein degradation. These results extend our understanding of lipid bilayer stress in the UPR and provide a foundation for mechanistic investigation of this fascinating intersection between ceramide metabolism, membrane homeostasis, and the UPR.

Pilot trial of perampanel on peritumoral hyperexcitability and clinical outcomes in newly diagnosed high-grade glioma

Background

Glutamatergic neuron-glioma synaptogenesis and peritumoral hyperexcitability promote glioma growth in a positive feedback loop. The objective of this study was to evaluate the feasibility and estimated effect sizes of the AMPA-R antagonist, perampanel, on intraoperative electrophysiologic hyperexcitability and clinical outcomes.

Methods

An open-label trial was performed comparing perampanel to standard of care (SOC) in patients undergoing resection of newly-diagnosed radiologic high-grade glioma. Perampanel was administered as a pre-operative loading dose followed by maintenance therapy until progressive disease or up to 12-months. SOC treatment involved levetiracetam for 7-days or as clinically indicated. The primary outcome of hyperexcitability was defined by intra-operative electrocorticography high frequency oscillation (HFO) rates. Seizure-freedom and overall survival (OS) were estimated by the Kaplan-Meier method. Tissue concentrations of perampanel, levetiracetam, and metabolites were measured by mass spectrometry.

Results

HFO rates were similar between perampanel-treated and SOC cohorts. The trial was terminated early after interim analysis for futility, and outcomes assessed in 11 patients (7 perampanel-treated, 4 SOC). Over a median 281 days of post-enrollment follow-up, 27% of patients had seizures, including 14% treated with perampanel and 50% treated with SOC. OS in perampanel-treated patients was similar to a glioblastoma reference cohort (p=0.81). Glutamate concentrations in surface biopsies were positively correlated with HFO rates in adjacent electrode contacts and were not significantly associated with treatment assignment or drug concentrations.

Conclusions

A peri-operative loading regimen of perampanel was safe and well-tolerated, with similar peritumoral hyperexcitability as in levetiracetam-treated patients. Maintenance anti-glutamatergic therapy was not observed to impact survival outcomes.