An acute rheumatic fever immune signature comprising inflammatory markers, IgG3, and Streptococcus pyogenes-specific antibodies.

Understanding the immune profile of acute rheumatic fever (ARF), a serious post-infectious sequelae of Streptococcal pyogenes (group A Streptococcus [GAS]), could inform disease pathogenesis and management. Circulating cytokines, immunoglobulins, and complement were analyzed in participants with first-episode ARF, swab-positive GAS pharyngitis and matched healthy controls. A striking elevation of total IgG3 was observed in ARF (90% > clinical reference range for normal). ARF was also associated with an inflammatory triad with significant correlations between interleukin-6, C-reactive protein, and complement C4 absent in controls. Quantification of GAS-specific antibody responses revealed that subclass polarization was remarkably consistent across the disease spectrum; conserved protein antigens polarized to IgG1, while M-protein responses polarized to IgG3 in all groups. However, the magnitude of responses was significantly higher in ARF. Taken together, these findings emphasize the association of exaggerated GAS antibody responses, IgG3, and inflammatory cytokines in ARF and suggest IgG3 testing could beneficially augment clinical diagnosis.

Effect of Insecticide Exposure Across Multiple Generations of the Earthworm Eisenia andrei.

The toxicity of neonicotinoids and many of their replacement insecticides to nontarget soil invertebrates such as earthworms has previously been established. However, the long-term effects of these substances on these organisms are largely unknown. In the field of soil ecotoxicology, lumbricid earthworms such as Eisenia andrei are used extensively due to the availability of standardized test methods and their adaptability to laboratory culture and testing. Multigenerational studies have gained popularity and attention in recent years, with a shift toward the use of long-term assays and lower concentrations of test chemicals. The use of exposure concentrations that include those measured in a monitoring program carried out by the Government of Ontario presents a realistic exposure scenario that may not show significant effects in contemporary, shorter term studies. We used current standardized test methods as a basis for the development of multigenerational studies on E. andrei. The effects of exposure to a single application of the insecticides thiamethoxam and cyantraniliprole on the survival and reproduction of E. andrei were observed over three (thiamethoxam) or two (cyantraniliprole) generations using consecutive reproduction tests. No significant impacts on adult survival were reported in any generation for either insecticide, whereas reproduction decreased between the first and second generations in the thiamethoxam test, with median effective concentration (EC50) values of 0.022 mg/kg dry weight reported for the first generation compared with 0.002 mg/kg dry weight in the second generation. For cyantraniliprole, an EC50 of 0.064 was determined for the first generation compared with 0.016 mg/kg dry weight in the second generation. A third generation was completed for the thiamethoxam test, and a significant decrease in reproduction was observed in all treatments and controls compared with previous generations. No significant difference between thiamethoxam treatments and the control treatment was reported for the third generation. Collectively, these data indicate that exposure of oligochaetes to these two insecticides at concentrations representative of field conditions may result in long-term stresses. Environ Toxicol Chem 2024;43:2058-2070. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Autoregulatory mechanism of enzyme activity by the nuclear localization signal of lysine-specific demethylase 1.

The N-terminal region of the human lysine-specific demethylase 1 (LSD1) has no predicted structural elements, contains a nuclear localization signal (NLS), undergoes multiple posttranslational modifications (PTMs), and acts as a protein-protein interaction hub. This intrinsically disordered region (IDR) extends from core LSD1 structure, resides atop the catalytic active site, and is known to be dispensable for catalysis. Here, we show differential nucleosome binding between the full-length and an N terminus deleted LSD1 and identify that a conserved NLS and PTM containing element of the N terminus contains an alpha helical structure, and that this conserved element impacts demethylation. Enzyme assays reveal that LSD1's own electropositive NLS amino acids 107 to 120 inhibit demethylation activity on a model histone 3 lysine 4 dimethyl (H3K4me2) peptide (Kiapp âˆ¼ 3.3 µM) and histone 3 lysine 4 dimethyl nucleosome substrates (IC50 ∼ 30.4 µM), likely mimicking the histone H3 tail. Further, when the identical, inhibitory NLS region contains phosphomimetic modifications, inhibition is partially relieved. Based upon these results and biophysical data, a regulatory mechanism for the LSD1-catalyzed demethylation reaction is proposed whereby NLS-mediated autoinhibition can occur through electrostatic interactions, and be partially relieved through phosphorylation that occurs proximal to the NLS. Taken together, the results highlight a dynamic and synergistic role for PTMs, intrinsically disordered regions, and structured regions near LSD1 active site and introduces the notion that phosphorylated mediated NLS regions can function to fine-tune chromatin modifying enzyme activity.

Characterization of Springtail (Arrhopalites caecus) for Use in Soil Ecotoxicity Testing.

Springtails (subclass: Collembola) represent one of the most extensively studied invertebrate groups in soil ecotoxicology. This is because of their ease of laboratory culture, significant ecological role, and sensitivity to environmental contaminants. Folsomia candida (family: Isotomidae) is a globally widespread parthenogenetic species that is prevalent in laboratory toxicity testing with springtails. Conversely, Arrhopalites caecus (family: Arrhopalitidae), a parthenogenic globular springtail species, remains untested in soil ecotoxicology. This species is found in diverse habitats, including cave systems and forest leaf litter, and has a global distribution. The sensitivity of A. caecus to environmental contaminants, such as neonicotinoid insecticides, as well as its life history and optimal culturing conditions, are largely unknown. The present study describes the establishment of a pure A. caecus laboratory culture and characterization of its life cycle and culturing conditions. We assessed the sensitivity of A. caecus to various insecticides, including exposures to the neonicotinoid thiamethoxam in soil and through a novel feeding assay as well as to clothianidin and cyantraniliprole in spiked soil exposures. In 7- and 14-day exposures to thiamethoxam in agricultural soil, the 50% lethal concentration (LC50) values were determined to be 0.129 mg/kg dry weight and 0.010 mg/kg dry weight, respectively. The 14-day LC50 for exposure to thiamethoxam via spiked food was determined to be 0.307 mg/kg dry weight. In addition, the 28-day 50% effect concentration for inhibition of juvenile production from cyantraniliprole exposure in the same soil type was 0.055 mg/kg dry weight. Challenges encountered in using this species included susceptibility to mite infestation and low adult survival rates in the 28-day cyantraniliprole test. Environ Toxicol Chem 2024;43:1820-1835. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Effect of proline content and histidine ligation on the dynamics of Ω-loop D and the peroxidase activity of iso-1-cytochrome c.

To study how proline residues affect the dynamics of Ω-loop D (residues 70 to 85) of cytochrome c, we prepared G83P and G83A variants of yeast iso-1-cytochrome c (iso-1-Cytc) in the presence and absence of a K73H mutation. Ω-loop D is important in controlling both the electron transfer function of Cytc and the peroxidase activity of Cytc used in apoptosis because it provides the Met80 heme ligand. The G83P and G83A mutations have no effect on the global stability of iso-1-Cytc in presence or absence of the K73H mutation. However, both mutations destabilize the His73-mediated alkaline conformer relative to the native state. pH jump stopped-flow experiments show that the dynamics of the His73-mediated alkaline transition are significantly enhanced by the G83P mutation. Gated electron transfer studies show that the enhanced dynamics result from an increased rate of return to the native state, whereas the rate of loss of Met80 ligation is unchanged by the G83P mutation. Thus, the G83P substitution does not stiffen the conformation of the native state. Because bis-His heme ligation occurs when Cytc binds to cardiolipin-containing membranes, we studied the effect of His73 ligation on the peroxidase activity of Cytc, which acts as an early signal in apoptosis by causing oxygenation of cardiolipin. We find that the His73 alkaline conformer suppresses the peroxidase activity of Cytc. Thus, the bis-His ligated state of Cytc formed upon binding to cardiolipin is a negative effector for the peroxidase activity of Cytc early in apoptosis.

Comparison of Established and Novel Insecticides on Survival and Reproduction of Folsomia candida.

Neonicotinoids have been among the most widely and abundantly used insecticides for most of the current century. The effects of these substances on nontarget terrestrial and aquatic organisms have resulted in a significant decrease in their use in many parts of the world. In response, the application of several novel classes of insecticides including diamides, ketoenols, pyridines, and butenolides has significantly increased. The hexapod subclass Collembola is an ecologically significant and widely distributed group of soil invertebrates often found in leaf litter and in surficial soils. We exposed the parthenogenic collembolan species Folsomia candida to six insecticides in a sandy loam soil for 28 days, including two neonicotinoids (thiamethoxam and clothianidin), a diamide (cyantraniliprole), a ketoenol (spirotetramat), a pyridine (flonicamid), and a butanolide (flupyradifurone) to assess the effect of each insecticide on survival and reproduction. Clothianidin, thiamethoxam, and cyantraniliprole (median effective concentration [EC50] values for reproduction: 0.19, 0.38, and 0.49 mg/kg soil, respectively) had a greater effect on survival and reproduction of F. candida than flupyradifurone, spirotetramat, and flonicamid (EC50 values for reproduction: 0.73, >3.08, and 5.20 mg/kg soil, respectively). All significant impacts found in our study were observed at concentrations below concentrations of the active ingredients that would be expected in agricultural soils. Environ Toxicol Chem 2023;42:1516-1528. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Shifting the trajectory of therapeutic development for neurological and psychiatric disorders.

Clinical trials for central nervous system disorders often enroll patients with unrecognized heterogeneous diseases, leading to costly trials that have high failure rates. Here, we discuss the potential of emerging technologies and datasets to elucidate disease mechanisms and identify biomarkers to improve patient stratification and monitoring of disease progression in clinical trials for neuropsychiatric disorders. Greater efforts must be centered on rigorously standardizing data collection and sharing of methods, datasets, and analytical tools across sectors. To address health care disparities in clinical trials, diversity of genetic ancestries and environmental exposures of research participants and associated biological samples must be prioritized.

A common symptom geometry of mood improvement under sertraline and placebo associated with distinct neural patterns.

Importance: Understanding the mechanisms of major depressive disorder (MDD) improvement is a key challenge to determine effective personalized treatments. Objective: To perform a secondary analysis quantifying neural-to-symptom relationships in MDD as a function of antidepressant treatment. Design: Double blind randomized controlled trial. Setting: Multicenter. Participants: Patients with early onset recurrent depression from the public Establishing Moderators and Biosignatures of Antidepressant Response in Clinical Care (EMBARC) study. Interventions: Either sertraline or placebo during 8 weeks (stage 1), and according to response a second line of treatment for 8 additional weeks (stage 2). Main Outcomes and Measures: To identify a data-driven pattern of symptom variations during these two stages, we performed a Principal Component Analysis (PCA) on the variations of individual items of four clinical scales measuring depression, anxiety, suicidal ideas and manic-like symptoms, resulting in a univariate measure of clinical improvement. We then investigated how initial clinical and neural factors predicted this measure during stage 1. To do so, we extracted resting-state global brain connectivity (GBC) at baseline at the individual level using a whole-brain functional network parcellation. In turn, we computed a linear model for each brain parcel with individual data-driven clinical improvement scores during stage 1 for each group. Results: 192 patients (127 women), age 37.7 years old (standard deviation: 13.5), were included. The first PC (PC1) capturing 20% of clinical variation was similar across treatment groups at stage 1 and stage 2, suggesting a reproducible pattern of symptom improvement. PC1 patients' scores significantly differed according to treatment during stage 1, whereas no difference of response was evidenced between groups with the Clinical Global Impressions (CGI). Baseline GBC correlated to stage 1 PC1 scores in the sertraline, but not in the placebo group. Conclusions and Relevance: Using data-driven reduction of symptoms scales, we identified a common profile of symptom improvement across placebo and sertraline. However, the neural patterns of baseline that mapped onto symptom improvement distinguished between treatment and placebo. Our results underscore that mapping from data-driven symptom improvement onto neural circuits is vital to detect treatment-responsive neural profiles that may aid in optimal patient selection for future trials.

Kappa opioid receptor antagonism protects working memory performance from mild stress exposure in Rhesus macaques.

Extensive preclinical and emerging clinical evidence point to an involvement of the kappa opioid receptor (KOR) in brain networks that promotes neurobehavioral stability. KOR expression in mesolimbic and mesocortical pathways has been the basis for characterizing the role of this receptor system in regulating motivation and emotion; however, the involvement of the KOR system in higher-order executive processes such as working memory (WM) is not well-understood. WM is readily impaired with uncontrollable stress exposure and is dysregulated in many neurobehavioral disorders. To empirically evaluate the role of the KOR system on WM performance, we administered a selective KOR antagonist, NMRA-140 (0, 0.1, 0.3, 1.0 mg/kg, intramuscular) to monkeys under both stress and non-stress conditions. In this study, NMRA-140 was co-administered with FG7142, a benzodiazepine inverse agonist, known to produce a mild stress response and to impair WM function in monkeys. NMRA-140 protected WM performance from the detrimental effects of FG7142-induced stress and exhibited no significant effect under non-stress conditions. Collectively, these data highlight the functional influence of the KOR system in mediating stress-induced dysfunction of executive processes and suggest that modulating KOR activity could offer therapeutic benefit in stress-related neurobehavioral disorders.

Mapping brain-behavior space relationships along the psychosis spectrum.

Difficulties in advancing effective patient-specific therapies for psychiatric disorders highlight a need to develop a stable neurobiologically grounded mapping between neural and symptom variation. This gap is particularly acute for psychosis-spectrum disorders (PSD). Here, in a sample of 436 PSD patients spanning several diagnoses, we derived and replicated a dimensionality-reduced symptom space across hallmark psychopathology symptoms and cognitive deficits. In turn, these symptom axes mapped onto distinct, reproducible brain maps. Critically, we found that multivariate brain-behavior mapping techniques (e.g. canonical correlation analysis) do not produce stable results with current sample sizes. However, we show that a univariate brain-behavioral space (BBS) can resolve stable individualized prediction. Finally, we show a proof-of-principle framework for relating personalized BBS metrics with molecular targets via serotonin and glutamate receptor manipulations and neural gene expression maps derived from the Allen Human Brain Atlas. Collectively, these results highlight a stable and data-driven BBS mapping across PSD, which offers an actionable path that can be iteratively optimized for personalized clinical biomarker endpoints.

Screening strategies for identifying RNA- and ribonucleoprotein-targeted compounds.

The past few years have witnessed important breakthroughs in the identification of compounds that specifically bind and regulate RNAs and in optimizing them for therapeutic use. Here, we review successful and unsuccessful approaches in screening for RNA-targeted small molecules. We discuss advantages and disadvantages of the different screening techniques and variables that affect the outcome of RNA-screening projects. We also highlight key challenges that hamper the development of quality RNA ligands, especially the still-low availability of RNA-specific compound libraries and the poor understanding of RNA structural dynamics. We conclude that the development of new RNA-targeting drugs would greatly benefit from integration of the power of high-throughput screening technologies with improved biochemical, structural, and computational characterization of RNA targets.

Differential effects of novel kappa opioid receptor antagonists on dopamine neurons using acute brain slice electrophysiology.

Activation of the kappa opioid receptor (KOR) contributes to the aversive properties of stress, and modulates key neuronal circuits underlying many neurobehavioral disorders. KOR agonists directly inhibit ventral tegmental area (VTA) dopaminergic neurons, contributing to aversive responses (Margolis et al. 2003, 2006); therefore, selective KOR antagonists represent a novel therapeutic approach to restore circuit function. We used whole cell electrophysiology in acute rat midbrain slices to evaluate pharmacological properties of four novel KOR antagonists: BTRX-335140, BTRX-395750, PF-04455242, and JNJ-67953964. Each compound concentration-dependently reduced the outward current induced by the KOR selective agonist U-69,593. BTRX-335140 and BTRX-395750 fully blocked U-69,593 currents (IC50 = 1.2 ± 0.9 and 1.2 ± 1.3 nM, respectively). JNJ-67953964 showed an IC50 of 3.0 ± 4.6 nM. PF-04455242 exhibited partial antagonist activity asymptoting at 55% blockade (IC50 = 6.7 ± 15.1 nM). In 3/8 of neurons, 1 µM PF-04455242 generated an outward current independent of KOR activation. BTRX-335140 (10 nM) did not affect responses to saturating concentrations of the mu opioid receptor (MOR) agonist DAMGO or the delta opioid receptor (DOR) agonist DPDPE, while JNJ-67953964 (10 nM) partially blocked DAMGO and DPDPE responses. Importantly, BTRX-335140 (10 nM) rapidly washed out with complete recovery of U-69,593 responses within 10 min. Collectively, we show electrophysiological evidence of key differences amongst KOR antagonists that could impact their therapeutic potential and have not been observed using recombinant systems. The results of this study demonstrate the value of characterizing compounds in native neuronal tissue and within circuits implicated in the neurobehavioral disorders of interest.

Differential Modulation of Ventral Tegmental Area Circuits by the Nociceptin/Orphanin FQ System.

The neuropeptide nociceptin/orphanin FQ (N/OFQ) can be released by stressors and is associated with disorders of emotion regulation and reward processing. N/OFQ and its receptor, NOP, are enriched in dopaminergic pathways, and intra-ventricular agonist delivery decreases dopamine levels in the dorsal striatum, nucleus accumbens (NAc), and ventral tegmental area (VTA). We used whole-cell electrophysiology in acute rat midbrain slices to investigate synaptic actions of N/OFQ. N/OFQ was primarily inhibitory, causing outward currents in both immunocytochemically identified dopaminergic (tyrosine hydroxylase positive (TH(+))) and non-dopaminergic (TH(-)) VTA neurons; effect at 1 µm: 20 ± 4 pA. Surprisingly, this effect was mediated by augmentation of postsynaptic GABAAR currents, unlike the substantia nigra pars compacta (SNc), where the N/OFQ-induced outward currents were K+ channel dependent. A smaller population, 17% of all VTA neurons, responded to low concentrations of N/OFQ with inward currents (10 nm: -11 ± 2 pA). Following 100 nm N/OFQ, the response to a second N/OFQ application was markedly diminished in VTA neurons (14 ± 10% of first response) but not in SNc neurons (90 ± 20% of first response). N/OFQ generated outward currents in medial prefrontal cortex (mPFC)-projecting VTA neurons, but inward currents in a subset of posterior anterior cingulate cortex (pACC)-projecting VTA neurons. While N/OFQ inhibited NAc-projecting VTA cell bodies, it had little effect on electrically or optogenetically evoked terminal dopamine release in the NAc measured ex vivo with fast scan cyclic voltammetry (FSCV). These results extend our understanding of the N/OFQ system in brainstem circuits implicated in many neurobehavioral disorders.

Extracellular Vesicles Mediate Neuroprotection and Functional Recovery after Traumatic Brain Injury.

The lack of effective therapies for moderate-to-severe traumatic brain injuries (TBIs) leaves patients with lifelong disabilities. Neural stem cells (NSCs) have demonstrated great promise for neural repair and regeneration. However, direct evidence to support their use as a cell replacement therapy for neural injuries is currently lacking. We hypothesized that NSC-derived extracellular vesicles (NSC EVs) mediate repair indirectly after TBI by enhancing neuroprotection and therapeutic efficacy of endogenous NSCs. We evaluated the short-term effects of acute intravenous injections of NSC EVs immediately following a rat TBI. Male NSC EV-treated rats demonstrated significantly reduced lesion sizes, enhanced presence of endogenous NSCs, and attenuated motor function impairments 4 weeks post-TBI, when compared with vehicle- and TBI-only male controls. Although statistically not significant, we observed a therapeutic effect of NSC EVs on brain lesion volume, nestin expression, and behavioral recovery in female subjects. Our study demonstrates the neuroprotective and functional benefits of NSC EVs for treating TBI and points to gender-dependent effects on treatment outcomes, which requires further investigation.

Machine Learning Models Identify Multimodal Measurements Highly Predictive of Transdiagnostic Symptom Severity for Mood, Anhedonia, and Anxiety.

BACKGROUND: Insights from neuroimaging-based biomarker research have not yet translated into clinical practice. This translational gap may stem from a focus on diagnostic classification, rather than on prediction of transdiagnostic psychiatric symptom severity. Currently, no transdiagnostic, multimodal predictive models of symptom severity that include neurobiological characteristics have emerged. METHODS: We built predictive models of 3 common symptoms in psychiatric disorders (dysregulated mood, anhedonia, and anxiety) from the Consortium for Neuropsychiatric Phenomics dataset (N = 272), which includes clinical scale assessments, resting-state functional magnetic resonance imaging (MRI), and structural MRI measures from patients with schizophrenia, bipolar disorder, and attention-deficit/hyperactivity disorder and healthy control subjects. We used an efficient, data-driven feature selection approach to identify the most predictive features from these high-dimensional data. RESULTS: This approach optimized modeling and explained 65% to 90% of variance across the 3 symptom domains, compared to 22% without using the feature selection approach. The top performing multimodal models retained a high level of interpretability that enabled several clinical and scientific insights. First, to our surprise, structural features did not substantially contribute to the predictive strength of these models. Second, the Temperament and Character Inventory scale emerged as a highly important predictor of symptom variation across diagnoses. Third, predictive resting-state functional MRI connectivity features were widely distributed across many intrinsic resting-state networks. CONCLUSIONS: Combining resting-state functional MRI with select questions from clinical scales enabled high prediction of symptom severity across diagnostically distinct patient groups and revealed that connectivity measures beyond a few intrinsic resting-state networks may carry relevant information for symptom severity.

Systems immunology reveals a linked IgG3-C4 response in patients with acute rheumatic fever.

Acute rheumatic fever (ARF) and chronic rheumatic heart disease (RHD) are autoimmune sequelae of a Group A streptococcal infection with significant global mortality and poorly understood pathogenesis. Immunoglobulin and complement deposition were observed in ARF/RHD valve tissue over 50 years ago, yet contemporary investigations have been lacking. This study applied systems immunology to investigate the relationships between the complement system and immunoglobulin in ARF. Patients were stratified by C-reactive protein (CRP) concentration into high (≥10 µg mL-1 ) and low (<10 µg mL-1 ) groups to distinguish those with clinically significant inflammatory processes from those with abating inflammation. The circulating concentrations of 17 complement factors and six immunoglobulin isotypes and subclasses were measured in ARF patients and highly matched healthy controls using multiplex bead-based immunoassays. An integrative statistical approach combining feature selection and principal component analysis revealed a linked IgG3-C4 response in ARF patients with high CRP that was absent in controls. Strikingly, both IgG3 and C4 were elevated above clinical reference ranges, suggesting these features are a marker of ARF-associated inflammation. Humoral immunity in response to M protein, an antigen implicated in ARF pathogenesis, was completely polarized to IgG3 in the patient group. Furthermore, the anti-M-protein IgG3 response was correlated with circulating IgG3 concentration, highlighting a potential role for this potent immunoglobulin subclass in disease. In conclusion, a linked IgG3-C4 response appears important in the initial, inflammatory stage of ARF and may have immediate utility as a clinical biomarker given the lack of specific diagnostic tests currently available.

Therapeutic Approaches for NOP Receptor Antagonists in Neurobehavioral Disorders: Clinical Studies in Major Depressive Disorder and Alcohol Use Disorder with BTRX-246040 (LY2940094).

Conventional antidepressants increase the efflux of biogenic amine neurotransmitters (the monoamine hypothesis of depression) in the central nervous system (CNS) and are the principle drugs used to treat major depressive disorder (MDD). However, the lack of efficacy in some patients, the slow onset of action, and the side effect profiles of existing antidepressants necessitate the exploration of additional treatment options. The discovery of the nociceptin/orphanin FQ peptide NOP receptor (N/OFQ-NOP receptor) system and its characterization in preclinical biological and pharmacological stress-related conditions supports the potential antidepressant and anti-stress properties of a NOP receptor antagonist for the treatment of neurobehavioral disorders. BTRX-246040 (formerly LY2940094) was designed to test this hypothesis in the clinic. A small clinical proof of concept study demonstrated efficacy of BTRX-246040 in MDD patients. In this study, BTRX-246040 (40 mg, p.o.) significantly reduced negative bias as assessed by the facial recognition test within 1 week of treatment and decreased depression symptoms after 8 weeks. BTRX-246040 also reduced depression symptoms in a second trial with heavy alcohol drinkers. Given the comorbidity of MDD and alcohol use disorder, a compound with such effects in patients could be a valuable addition to the medications available. A proof of concept study showed efficacy of BTRX-246040 in reducing heavy drinking and increasing the probability of abstinence in individuals diagnosed with alcohol dependence. In addition, plasma levels of gamma-glutamyl transferase were decreased by BTRX-246040 compared to placebo control implying improvement in liver function. Collectively, the clinical data reviewed within this chapter suggest that BTRX-264040 functions to normalize dysfunction in reward circuits. The overall efficacy and safety of this compound with a novel mechanism of action are encouraging of further clinical development. BTRX-246040 is currently under development for MDD by BlackThorn Therapeutics.

Dysregulated IL-1ß-GM-CSF Axis in Acute Rheumatic Fever That Is Limited by Hydroxychloroquine.

BACKGROUND: Acute rheumatic fever (ARF) and rheumatic heart disease are autoimmune consequences of group A streptococcus infection and remain major causes of cardiovascular morbidity and mortality around the world. Improved treatment has been stymied by gaps in understanding key steps in the immunopathogenesis of ARF and rheumatic heart disease. This study aimed to identify (1) effector T cell cytokine(s) that might be dysregulated in the autoimmune response of patients with ARF by group A streptococcus, and (2) an immunomodulatory agent that suppresses this response and could be clinically translatable to high-risk patients with ARF. METHODS: The immune response to group A streptococcus was analyzed in peripheral blood mononuclear cells from an Australian Aboriginal ARF cohort by a combination of multiplex cytokine array, flow cytometric analysis, and global gene expression analysis by RNA sequencing. The immunomodulatory drug hydroxychloroquine was tested for effects on this response. RESULTS: We found a dysregulated interleukin-1ß-granulocyte-macrophage colony-stimulating factor (GM-CSF) cytokine axis in ARF peripheral blood mononuclear cells exposed to group A streptococcus in vitro, whereby persistent interleukin-1ß production is coupled to overproduction of GM-CSF and selective expansion of CXCR3+CCR4-CCR6- CD4 T cells. CXCR3+CCR4-CCR6- CD4 T cells are the major source of GM-CSF in human CD4 T cells and CXCL10, a CXCR3 ligand and potent T helper 1 chemoattractant, was elevated in sera from patients with ARF. GM-CSF has recently emerged as a key T cell-derived effector cytokine in numerous autoimmune diseases, including myocarditis, and the production of CXCL10 may explain selective trafficking of these cells to the heart. We provide evidence that interleukin-1ß amplifies the expansion of GM-CSF-expressing CD4 T cells, which is effectively suppressed by hydroxychloroquine. RNA sequencing showed shifts in gene expression profiles and differentially expressed genes in peripheral blood mononuclear cells derived from patients at different clinical stages of ARF. CONCLUSIONS: Given the safety profile of hydroxychloroquine and its clinical pedigree in treating autoimmune diseases such as rheumatoid arthritis, where GM-CSF plays a pivotal role, we propose that hydroxychloroquine could be repurposed to reduce the risk of rheumatic heart disease after ARF.