Five Hypotheses on the Origins of Temperature Dependence of 77Se NMR Shifts in Diselenides.

Notable thermal shifts in diselenides have been documented in 77Se NMR for more than 50 years, but no satisfactory explanation has been found. Here, five hypotheses are considered as possible explanations for the large temperature dependence of the 77Se chemical shifts of diaryl and dialkyl diselenides compared to monoselenides and selenols. Density functional theory calculations are provided to bolster hypotheses and better understand the effects of barrier height and dipole energies. It is proposed that the temperature dependence of diselenide 77Se NMR chemical shifts is due to rotation around the Se-Se bond and sampling of twisted conformers at higher temperatures. The molecular twisting is solvent dependent; here, DMSO-d6 and toluene-d8 were evaluated. No correlation was established between para-substituents on diaryl diselenides and the magnitude of the change in the 77Se NMR shift (Δδ) with temperature.

Theoretical basis for interpreting heterodyne chirality-selective sum frequency generation spectra of water.

Chirality-selective vibrational sum frequency generation (chiral SFG) spectroscopy has emerged as a powerful technique for the study of biomolecular hydration water due to its sensitivity to the induced chirality of the first hydration shell. Thus far, water O-H vibrational bands in phase-resolved heterodyne chiral SFG spectra have been fit using one Lorentzian function per vibrational band, and the resulting fit has been used to infer the underlying frequency distribution. Here, we show that this approach may not correctly reveal the structure and dynamics of hydration water. Our analysis illustrates that the chiral SFG responses of symmetric and asymmetric O-H stretch modes of water have opposite phase and equal magnitude and are separated in energy by intramolecular vibrational coupling and a heterogeneous environment. The sum of the symmetric and asymmetric responses implies that an O-H stretch in a heterodyne chiral SFG spectrum should appear as two peaks with opposite phase and equal amplitude. Using pairs of Lorentzian functions to fit water O-H stretch vibrational bands, we improve spectral fitting of previously acquired experimental spectra of model ß-sheet proteins and reduce the number of free parameters. The fitting allows us to estimate the vibrational frequency distribution and thus reveals the molecular interactions of water in hydration shells of biomolecules directly from chiral SFG spectra.

LassoHTP: A High-Throughput Computational Tool for Lasso Peptide Structure Construction and Modeling.

Lasso peptides are a subclass of ribosomally synthesized and post-translationally modified peptides with a slipknot conformation. With superior thermal stability, protease resistance, and antimicrobial activity, lasso peptides are promising candidates for bioengineering and pharmaceutical applications. To enable high-throughput computational prediction and design of lasso peptides, we developed a software, LassoHTP, for automatic lasso peptide structure construction and modeling. LassoHTP consists of three modules, including the scaffold constructor, mutant generator, and molecular dynamics (MD) simulator. With a user-provided sequence and conformational annotation, LassoHTP can either generate the structure and conformational ensemble as is or conduct random mutagenesis. We used LassoHTP to construct eight known lasso peptide structures de novo and to simulate their conformational ensembles for 100 ns MD simulations. For benchmarking, we calculated the root mean square deviation (RMSD) of these ensembles with reference to their experimental crystal or NMR PDB structures; we also compared these RMSD values against those of the MD ensembles that are initiated from the PDB structures. Dihedral principal component analysis was also conducted. The results show that the LassoHTP-initiated ensembles are similar to those of the PDB-initiated ensembles. LassoHTP offers a computational platform to develop strategies for lasso peptide prediction and design.

The ReFRAME library as a comprehensive drug repurposing library and its application to the treatment of cryptosporidiosis.

The chemical diversity and known safety profiles of drugs previously tested in humans make them a valuable set of compounds to explore potential therapeutic utility in indications outside those originally targeted, especially neglected tropical diseases. This practice of "drug repurposing" has become commonplace in academic and other nonprofit drug-discovery efforts, with the appeal that significantly less time and resources are required to advance a candidate into the clinic. Here, we report a comprehensive open-access, drug repositioning screening set of 12,000 compounds (termed ReFRAME; Repurposing, Focused Rescue, and Accelerated Medchem) that was assembled by combining three widely used commercial drug competitive intelligence databases (Clarivate Integrity, GVK Excelra GoStar, and Citeline Pharmaprojects), together with extensive patent mining of small molecules that have been dosed in humans. To date, 12,000 compounds (∼80% of compounds identified from data mining) have been purchased or synthesized and subsequently plated for screening. To exemplify its utility, this collection was screened against Cryptosporidium spp., a major cause of childhood diarrhea in the developing world, and two active compounds previously tested in humans for other therapeutic indications were identified. Both compounds, VB-201 and a structurally related analog of ASP-7962, were subsequently shown to be efficacious in animal models of Cryptosporidium infection at clinically relevant doses, based on available human doses. In addition, an open-access data portal (https://reframedb.org) has been developed to share ReFRAME screen hits to encourage additional follow-up and maximize the impact of the ReFRAME screening collection.

Cell-specific discrimination of desmosterol and desmosterol mimetics confers selective regulation of LXR and SREBP in macrophages.

Activation of liver X receptors (LXRs) with synthetic agonists promotes reverse cholesterol transport and protects against atherosclerosis in mouse models. Most synthetic LXR agonists also cause marked hypertriglyceridemia by inducing the expression of sterol regulatory element-binding protein (SREBP)1c and downstream genes that drive fatty acid biosynthesis. Recent studies demonstrated that desmosterol, an intermediate in the cholesterol biosynthetic pathway that suppresses SREBP processing by binding to SCAP, also binds and activates LXRs and is the most abundant LXR ligand in macrophage foam cells. Here we explore the potential of increasing endogenous desmosterol production or mimicking its activity as a means of inducing LXR activity while simultaneously suppressing SREBP1c-induced hypertriglyceridemia. Unexpectedly, while desmosterol strongly activated LXR target genes and suppressed SREBP pathways in mouse and human macrophages, it had almost no activity in mouse or human hepatocytes in vitro. We further demonstrate that sterol-based selective modulators of LXRs have biochemical and transcriptional properties predicted of desmosterol mimetics and selectively regulate LXR function in macrophages in vitro and in vivo. These studies thereby reveal cell-specific discrimination of endogenous and synthetic regulators of LXRs and SREBPs, providing a molecular basis for dissociation of LXR functions in macrophages from those in the liver that lead to hypertriglyceridemia.

Repurposing isoxazoline veterinary drugs for control of vector-borne human diseases.

Isoxazolines are oral insecticidal drugs currently licensed for ectoparasite control in companion animals. Here we propose their use in humans for the reduction of vector-borne disease incidence. Fluralaner and afoxolaner rapidly killed Anopheles, Aedes, and Culex mosquitoes and Phlebotomus sand flies after feeding on a drug-supplemented blood meal, with IC50 values ranging from 33 to 575 nM, and were fully active against strains with preexisting resistance to common insecticides. Based on allometric scaling of preclinical pharmacokinetics data, we predict that a single human median dose of 260 mg (IQR, 177-407 mg) for afoxolaner, or 410 mg (IQR, 278-648 mg) for fluralaner, could provide an insecticidal effect lasting 50-90 days against mosquitoes and Phlebotomus sand flies. Computational modeling showed that seasonal mass drug administration of such a single dose to a fraction of a regional population would dramatically reduce clinical cases of Zika and malaria in endemic settings. Isoxazolines therefore represent a promising new component of drug-based vector control.

Harnessing electronic medical records to advance research on multiple sclerosis.

BACKGROUND: Electronic medical records (EMR) data are increasingly used in research, but no studies have yet evaluated similarity between EMR and research-quality data and between characteristics of an EMR multiple sclerosis (MS) population and known natural MS history. OBJECTIVES: To (1) identify MS patients in an EMR system and extract clinical data, (2) compare EMR-extracted data with gold-standard research data, and (3) compare EMR MS population characteristics to expected MS natural history. METHODS: Algorithms were implemented to identify MS patients from the University of California San Francisco EMR, de-identify the data and extract clinical variables. EMR-extracted data were compared to research cohort data in a subset of patients. RESULTS: We identified 4142 MS patients via search of the EMR and extracted their clinical data with good accuracy. EMR and research values showed good concordance for Expanded Disability Status Scale (EDSS), timed-25-foot walk, and subtype. We replicated several expected MS epidemiological features from MS natural history including higher EDSS for progressive versus relapsing-remitting patients and for male versus female patients and increased EDSS with age at examination and disease duration. CONCLUSION: Large real-world cohorts algorithmically extracted from the EMR can expand opportunities for MS clinical research.

Dissociated sterol-based liver X receptor agonists as therapeutics for chronic inflammatory diseases.

Liver X receptor (LXR), a nuclear hormone receptor, is an essential regulator of immune responses. Activation of LXR-mediated transcription by synthetic agonists, such as T0901317 and GW3965, attenuates progression of inflammatory disease in animal models. However, the adverse effects of these conventional LXR agonists in elevating liver lipids have impeded exploitation of this intriguing mechanism for chronic therapy. Here, we explore the ability of a series of sterol-based LXR agonists to alleviate inflammatory conditions in mice without hepatotoxicity. We show that oral treatment with sterol-based LXR agonists in mice significantly reduces dextran sulfate sodium colitis-induced body weight loss, which is accompanied by reduced expression of inflammatory markers in the large intestine. The anti-inflammatory property of these agonists is recapitulated in vitro in mouse lamina propria mononuclear cells, human colonic epithelial cells, and human peripheral blood mononuclear cells. In addition, treatment with LXR agonists dramatically suppresses inflammatory cytokine expression in a model of traumatic brain injury. Importantly, in both disease models, the sterol-based agonists do not affect the liver, and the conventional agonist T0901317 results in significant liver lipid accumulation and injury. Overall, these results provide evidence for the development of sterol-based LXR agonists as novel therapeutics for chronic inflammatory diseases.-Yu, S., Li, S., Henke, A., Muse, E. D., Cheng, B., Welzel, G., Chatterjee, A. K., Wang, D., Roland, J., Glass, C. K., Tremblay, M. Dissociated sterol-based liver X receptor agonists as therapeutics for chronic inflammatory diseases.

Spoxazomicin D and Oxachelin C, Potent Neuroprotective Carboxamides from the Appalachian Coal Fire-Associated Isolate Streptomyces sp. RM-14-6.

The isolation and structure elucidation of six new bacterial metabolites [spoxazomicin D (2), oxachelins B and C (4, 5), and carboxamides 6-8] and 11 previously reported bacterial metabolites (1, 3, 9-12a, and 14-18) from Streptomyces sp. RM-14-6 is reported. Structures were elucidated on the basis of comprehensive 1D and 2D NMR and mass spectrometry data analysis, along with direct comparison to synthetic standards for 2, 11, and 12a,b. Complete 2D NMR assignments for the known metabolites lenoremycin (9) and lenoremycin sodium salt (10) were also provided for the first time. Comparative analysis also provided the basis for structural revision of several previously reported putative aziridine-containing compounds [exemplified by madurastatins A1, B1, C1 (also known as MBJ-0034), and MBJ-0035] as phenol-dihydrooxazoles. Bioactivity analysis [including antibacterial, antifungal, cancer cell line cytotoxicity, unfolded protein response (UPR) modulation, and EtOH damage neuroprotection] revealed 2 and 5 as potent neuroprotectives and lenoremycin (9) and its sodium salt (10) as potent UPR modulators, highlighting new functions for phenol-oxazolines/salicylates and polyether pharmacophores.

Targeted Delivery of an Anti-inflammatory PDE4 Inhibitor to Immune Cells via an Antibody-drug Conjugate.

Phosphodiesterase 4 (PDE4) inhibitors are approved for the treatment of some moderate to severe inflammatory conditions. However, dose-limiting side effects in the central nervous system and gastrointestinal tract, including nausea, emesis, headache, and diarrhea, have impeded the broader therapeutic application of PDE4 inhibitors. We sought to exploit the wealth of validation surrounding PDE4 inhibition by improving the therapeutic index through generation of an antibody-drug conjugate (ADC) that selectively targets immune cells through the CD11a antigen. The resulting ADC consisted of a human αCD11a antibody (based on efalizumab clone hu1124) conjugated to an analog of the highly potent PDE4 inhibitor GSK256066. Both the human αCD11a ADC and a mouse surrogate αCD11a ADC (based on the M17 clone) rapidly internalized into immune cells and suppressed lipololysaccharide (LPS)-induced TNFα secretion in primary human monocytes and mouse peritoneal cells, respectively. In a carrageenan-induced air pouch inflammation mouse model, treatment with the ADC significantly reduced inflammatory cytokine production in the air pouch exudate. Overall, these results provide compelling evidence for the feasibility of delivering drugs with anti-inflammatory activity selectively to the immune compartment via CD11a and the development of tissue-targeted PDE4 inhibitors as a promising therapeutic modality for treating inflammatory diseases.

An immunosuppressive antibody-drug conjugate.

We have developed a novel antibody-drug conjugate (ADC) that can selectively deliver the Lck inhibitor dasatinib to human T lymphocytes. This ADC is based on a humanized antibody that selectively binds with high affinity to CXCR4, an antigen that is selectively expressed on hematopoietic cells. The resulting dasatinib-antibody conjugate suppresses T-cell-receptor (TCR)-mediated T-cell activation and cytokine expression with low nM EC50 and has minimal effects on cell viability. This ADC may lead to a new class of selective immunosuppressive drugs with improved safety and extend the ADC strategy to the targeted delivery of kinase inhibitors for indications beyond oncology.

Adult-onset glutaric aciduria type I presenting with white matter abnormalities and subependymal nodules.

A 55-year-old female presented with a 6-year history of paresthesias, incontinence, spasticity, and gait abnormalities. Neuroimaging revealed white matter abnormalities associated with subependymal nodules. Biochemical evaluation noted increased serum C5-DC glutarylcarnitines and urine glutaric and 3-hydroxyglutaric acids. Evaluation of the glutaryl-CoA dehydrogenase (GCDH) gene revealed compound heterozygosity consisting of a novel variant (c.1219C>G; p.Leu407Val) and pathogenic mutation (c.848delT; p.L283fs). Together, these results were consistent with a diagnosis of adult-onset type I glutaric aciduria.

Targeted Delivery of LXR Agonist Using a Site-Specific Antibody-Drug Conjugate.

Liver X receptor (LXR) agonists have been explored as potential treatments for atherosclerosis and other diseases based on their ability to induce reverse cholesterol transport and suppress inflammation. However, this therapeutic potential has been hindered by on-target adverse effects in the liver mediated by excessive lipogenesis. Herein, we report a novel site-specific antibody-drug conjugate (ADC) that selectively delivers a LXR agonist to monocytes/macrophages while sparing hepatocytes. The unnatural amino acid para-acetylphenylalanine (pAcF) was site-specifically incorporated into anti-CD11a IgG, which binds the α-chain component of the lymphocyte function-associated antigen 1 (LFA-1) expressed on nearly all monocytes and macrophages. An aminooxy-modified LXR agonist was conjugated to anti-CD11a IgG through a stable, cathepsin B cleavable oxime linkage to afford a chemically defined ADC. The anti-CD11a IgG-LXR agonist ADC induced LXR activation specifically in human THP-1 monocyte/macrophage cells in vitro (EC50-27 nM), but had no significant effect in hepatocytes, indicating that payload delivery is CD11a-mediated. Moreover, the ADC exhibited higher-fold activation compared to a conventional synthetic LXR agonist T0901317 (Tularik) (3-fold). This novel ADC represents a fundamentally different strategy that uses tissue targeting to overcome the limitations of LXR agonists for potential use in treating atherosclerosis.

A small molecule MST1/2 inhibitor accelerates murine liver regeneration with improved survival in models of steatohepatitis.

Dysfunctional liver regeneration following surgical resection remains a major cause of postoperative mortality and has no therapeutic options. Without targeted therapies, the current treatment paradigm relies on supportive therapy until homeostasis can be achieved. Pharmacologic acceleration of regeneration represents an alternative therapeutic avenue. Therefore, we aimed to generate a small molecule inhibitor that could accelerate liver regeneration with an emphasis on diseased models, which represent a significant portion of patients who require surgical resection and are often not studied. Utilizing a clinically approved small molecule inhibitor as a parent compound, standard medicinal chemistry approaches were utilized to generate a small molecule inhibitor targeting serine/threonine kinase 4/3 (MST1/2) with reduced off-target effects. This compound, mCLC846, was then applied to preclinical models of murine partial hepatectomy, which included models of diet-induced metabolic dysfunction-associated steatohepatitis (MASH). mCLC846 demonstrated on target inhibition of MST1/2 and reduced epidermal growth factor receptor inhibition. The inhibitory effects resulted in restored pancreatic beta-cell function and survival under diabetogenic conditions. Liver-specific cell-line exposure resulted in Yes-associated protein activation. Oral delivery of mCLC846 perioperatively resulted in accelerated murine liver regeneration and improved survival in diet-induced MASH models. Bulk transcriptional analysis of regenerating liver remnants suggested that mCLC846 enhanced the normal regenerative pathways and induced them following liver resection. Overall, pharmacological acceleration of liver regeneration with mCLC846 was feasible, had an acceptable therapeutic index, and provided a survival benefit in models of diet-induced MASH.

Small-molecule inducer of ß cell proliferation identified by high-throughput screening.

The identification of factors that promote ß cell proliferation could ultimately move type 1 diabetes treatment away from insulin injection therapy and toward a cure. We have performed high-throughput, cell-based screens using rodent ß cell lines to identify molecules that induce proliferation of ß cells. Herein we report the discovery and characterization of WS6, a novel small molecule that promotes ß cell proliferation in rodent and human primary islets. In the RIP-DTA mouse model of ß cell ablation, WS6 normalized blood glucose and induced concomitant increases in ß cell proliferation and ß cell number. Affinity pulldown and kinase profiling studies implicate Erb3 binding protein-1 and the IκB kinase pathway in the mechanism of action of WS6.

Vaccine response in people with multiple sclerosis treated with fumarates.

People with multiple sclerosis (pwMS) have an increased risk of infection. As disease-modifying therapies (DMTs) and other treatments may interact with the immune system, there may be concerns about vaccine efficacy and safety. Therefore, it is important to evaluate possible interactions between DMTs and vaccines. The fumarates, dimethyl fumarate, diroximel fumarate, and monomethyl fumarate, are approved for the treatment of relapsing multiple sclerosis. This review assesses the evidence on vaccine response in pwMS treated with fumarates, with a particular focus on COVID-19 vaccines. Treatment with fumarates does not appear to result in blunting of humoral responses to vaccination; for COVID-19 vaccines, particularly RNA-based vaccines, evidence indicates antibody responses similar to those of healthy recipients. While data on the effect of fumarates on T-cell responses are limited, they do not indicate any significant blunting. COVID-19 vaccines impart a similar degree of protection against severe COVID-19 infection for pwMS on fumarates as in the general population. Adverse reactions following vaccination are generally consistent with those observed in the wider population; no additional safety signals have emerged in those on fumarates. Additionally, no increase in relapse has been observed in pwMS following vaccination. In pwMS receiving fumarates, vaccination is generally safe and elicits protective immune responses.

Real-World Efficacy of COVID-19 Pre-Exposure Prophylaxis with Tixagevimab/Cilgavimab in People with Multiple Sclerosis.

Vaccines against the SARS-CoV-2 virus were authorized for use by the Food and Drug Administration (FDA) in the United States and have proven effective for the prevention of morbidity and death from COVID-19. Certain immunosuppressant medications prevent the development of protective immunity following COVID-19 vaccination. In December 2021, the FDA issued an emergency use authorization (EUA) for a monoclonal-antibody combination of tixagevimab and cilgavimab, under the brand name Evusheld, for pre-exposure prophylaxis (PrEP) against COVID-19 for individuals with moderate-to-severe immune compromise. While a 77% reduction in symptomatic COVID-19 was observed in the PROVENT study, the trial was conducted prior to emergence of the B.1.1.529 Omicron variant. We suspected reduced efficacy of PrEP against Omicron subvariants. We conducted a retrospective cohort study comparing the prevalence of symptomatic COVID-19 infections between 1 January 2022 and 1 July 2022 in eligible patients treated with PrEP versus untreated using a questionnaire administered with the REDCap survey tool. Responses from 235 participants were included in the final analysis, with 176 untreated respondents and 59 in the PrEP cohort. Symptomatic COVID-19 infections were reported in 50 (28.4%) untreated participants and only 9 (15.3%) of those who received PrEP (p = 0.0557; OR 0.4536; 95% CI 0.2046 to 0.9599). Only two participants were hospitalized for COVID-19 infection, both in the untreated cohort. The reduction in COVID-19 infections did not achieve statistical significance, indicating diminished efficacy against Omicron variants.

COVID-19 Vaccine Response in People with Multiple Sclerosis Treated with Dimethyl Fumarate, Diroximel Fumarate, Natalizumab, Ocrelizumab, or Interferon Beta Therapy.

BACKGROUND: Some multiple sclerosis (MS) disease-modifying therapies (DMTs) impair responses to vaccines, emphasizing the importance of understanding COVID-19 vaccine immune responses in people with MS (PwMS) receiving different DMTs. METHODS: This prospective, open-label observational study enrolled 45 participants treated with natalizumab (n = 12), ocrelizumab (n = 16), fumarates (dimethyl fumarate or diroximel fumarate, n = 11), or interferon beta (n = 6); ages 18-65 years inclusive; stable on DMT for at least 6 months. Responder rates, anti-SARS-CoV-2 spike receptor-binding domain IgG (anti-RBD) geometric mean titers (GMTs), antigen-specific T cells, and vaccination-related adverse events were evaluated at baseline and 8, 24, 36, and 48 weeks after first mRNA-1273 (Moderna) dose. RESULTS: At 8 weeks post vaccination, all natalizumab-, fumarate-, and interferon beta-treated participants generated detectable anti-RBD IgG titers, compared to only 25% of the ocrelizumab cohort. At 24 and 36 weeks post vaccination, natalizumab-, fumarate-, and interferon beta-treated participants continued to demonstrate detectable anti-RBD IgG titers, whereas participants receiving ocrelizumab did not. Anti-RBD GMTs decreased 81.5% between 8 and 24 weeks post vaccination for the non-ocrelizumab-treated participants, with no significant difference between groups. At 36 weeks post vaccination, ocrelizumab-treated participants had higher proportions of spike-specific T cells compared to other treatment groups. Vaccine-associated side effects were highest in the ocrelizumab arm for most symptoms. CONCLUSIONS: These results suggest that humoral response to mRNA-1273 COVID-19 vaccine is preserved and similar in PwMS treated with natalizumab, fumarate, and interferon beta, but muted with ocrelizumab. All DMTs had preserved T cell response, including the ocrelizumab cohort, which also had a greater risk of vaccine-related side effects.

Identification of small-molecule inducers of pancreatic beta-cell expansion.

To identify small molecules that can induce beta-cell replication, a large chemical library was screened for proliferation of growth-arrested, reversibly immortalized mouse beta cells by using an automated high-throughput screening platform. A number of structurally diverse, active compounds were identified, including phorbol esters, which likely act through protein kinase C, and a group of thiophene-pyrimidines that stimulate beta-cell proliferation by activating the Wnt signaling pathway. A group of dihydropyridine (DHP) derivatives was also shown to reversibly induce beta-cell replication in vitro by activating L-type calcium channels (LTCCs). Our data suggest that the LTCC agonist 2a affects the expression of genes involved in cell cycle progression and cellular proliferation. Furthermore, treatment of beta cells with both LTCC agonist 2a and the Glp-1 receptor agonist Exendin-4 showed an additive effect on beta-cell replication. The identification of small molecules that induce beta-cell proliferation suggests that it may be possible to reversibly expand other quiescent cells to overcome deficits associated with degenerative and/or autoimmune diseases.

Advances in the Treatment of Neuromyelitis Optica Spectrum Disorder.

Neuromyelitis optica spectrum disorder (NMOSD) is a rare, relapsing-remitting neuroinflammatory disorder of the central nervous system. Advances in the understanding of NMOSD pathogenesis and identification of the NMO-specific pathogenic anti-AQP4 autoantibody have led to the development of highly effective disease-modifying strategies. Five placebo-controlled, randomized trials for NMOSD have been successfully completed as of 2020. These trials support the efficacy of rituximab and tocilizumab and led to the FDA approval of eculizumab, satralizumab and inebilizumab for NMOSD. Our review provides an update on these evidence-based disease-modifying therapies and discussed the treatment of acute relapses in NMOSD.