Critical care management of chimeric antigen receptor T-cell therapy recipients.

Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapeutic treatment concept that is changing the treatment approach to hematologic malignancies. The development of CAR T-cell therapy represents a prime example for the successful bench-to-bedside translation of advances in immunology and cellular therapy into clinical practice. The currently available CAR T-cell products have shown high response rates and long-term remissions in patients with relapsed/refractory acute lymphoblastic leukemia and relapsed/refractory lymphoma. However, CAR T-cell therapy can induce severe life-threatening toxicities such as cytokine release syndrome, neurotoxicity, or infection, which require rapid and aggressive medical treatment in the intensive care unit setting. In this review, the authors provide an overview of the state-of-the-art in the clinical management of severe life-threatening events in CAR T-cell recipients. Furthermore, key challenges that have to be overcome to maximize the safety of CAR T cells are discussed.

Air Pollution-Related Neurotoxicity Across the Life Span.

Air pollution is a complex mixture of gases and particulate matter, with adsorbed organic and inorganic contaminants, to which exposure is lifelong. Epidemiological studies increasingly associate air pollution with multiple neurodevelopmental disorders and neurodegenerative diseases, findings supported by experimental animal models. This breadth of neurotoxicity across these central nervous system diseases and disorders likely reflects shared vulnerability of their inflammatory and oxidative stress-based mechanisms and a corresponding ability to produce brain metal dyshomeo-stasis. Future research to define the responsible contaminants of air pollution underlying this neurotoxicity is critical to understanding mechanisms of these diseases and disorders and protecting public health.

Cilta-cel or Standard Care in Lenalidomide-Refractory Multiple Myeloma.

BACKGROUND: Ciltacabtagene autoleucel (cilta-cel), a B-cell maturation antigen (BCMA)-directed CAR T-cell therapy, is effective in heavily pretreated patients with relapsed or refractory multiple myeloma. We investigated cilta-cel in earlier treatment lines in patients with lenalidomide-refractory disease. METHODS: In this phase 3, randomized, open-label trial, we assigned patients with lenalidomide-refractory multiple myeloma to receive cilta-cel or the physician's choice of effective standard care. All the patients had received one to three previous lines of treatment. The primary outcome was progression-free survival. RESULTS: A total of 419 patients underwent randomization (208 to receive cilta-cel and 211 to receive standard care). At a median follow-up of 15.9 months (range, 0.1 to 27.3), the median progression-free survival was not reached in the cilta-cel group and was 11.8 months in the standard-care group (hazard ratio, 0.26; 95% confidence interval [CI], 0.18 to 0.38; P<0.001). Progression-free survival at 12 months was 75.9% (95% CI, 69.4 to 81.1) in the cilta-cel group and 48.6% (95% CI, 41.5 to 55.3) in the standard-care group. More patients in the cilta-cel group than in the standard-care group had an overall response (84.6% vs. 67.3%), a complete response or better (73.1% vs. 21.8%), and an absence of minimal residual disease (60.6% vs. 15.6%). Death from any cause was reported in 39 patients and 46 patients, respectively (hazard ratio, 0.78; 95% CI, 0.5 to 1.2). Most patients reported grade 3 or 4 adverse events during treatment. Among the 176 patients who received cilta-cel in the as-treated population, 134 (76.1%) had cytokine release syndrome (grade 3 or 4, 1.1%; no grade 5), 8 (4.5%) had immune effector cell-associated neurotoxicity syndrome (all grade 1 or 2), 1 had movement and neurocognitive symptoms (grade 1), 16 (9.1%) had cranial nerve palsy (grade 2, 8.0%; grade 3, 1.1%), and 5 (2.8%) had CAR-T-related peripheral neuropathy (grade 1 or 2, 2.3%; grade 3, 0.6%). CONCLUSIONS: A single cilta-cel infusion resulted in a lower risk of disease progression or death than standard care in lenalidomide-refractory patients with multiple myeloma who had received one to three previous therapies. (Funded by Janssen and Legend Biotech; CARTITUDE-4 ClinicalTrials.gov number, NCT04181827.).

Quadriparesis and paraparesis following chimeric antigen receptor T-cell therapy in children and adolescents.

ABSTRACT: Immune effector cell-associated neurotoxicity syndrome (ICANS) is a common but potentially severe adverse event associated with chimeric antigen receptor T-cell (CART) therapy, characterized by the development of acute neurologic symptoms following CART infusion. ICANS encompasses a wide clinical spectrum typified by mild to severe encephalopathy, seizures, and/or cerebral edema. As more patients have been treated with CART, new ICANS phenomenology has emerged. We present the clinical course of 5 children who developed acute onset of quadriparesis or paraparesis associated with abnormal brain and/or spine neuroimaging after infusion of CD19- or CD22-directed CART, adverse events not previously reported in children. Orthogonal data from autopsy studies, cerebrospinal fluid (CSF) flow cytometry, and CSF proteomics/cytokine profiling demonstrated chronic white matter destruction, but a notable lack of inflammatory pathologic changes and cell populations. Instead, children with quadriparesis or paraparesis post-CART therapy had lower levels of proinflammatory cytokines, such as interferon gamma, CCL17, CCL23, and CXCL10, than those who did not develop quadriparesis or paraparesis. Taken together, these findings imply a noninflammatory source of this newly described ICANS phenomenon in children. The pathophysiology of some neurologic symptoms following CART may therefore have a more complex etiology than exclusive T-cell activation and excessive cytokine production.

HERV-K (HML-2) Envelope Protein Induces Mitochondrial Depolarization and Neurotoxicity via Endolysosome Iron Dyshomeostasis.

Human endogenous retroviruses (HERVs) are associated with the pathogenesis of amyotrophic lateral sclerosis (ALS); a disease characterized by motor neuron degeneration and cell death. The HERV-K subtype HML-2 envelope protein (HERV-K Env) is expressed in the brain, spinal cord, and cerebrospinal fluid of people living with ALS and through CD98 receptor-linked interactions causes neurodegeneration. HERV-K Env-induced increases in oxidative stress are implicated in the pathogenesis of ALS, and ferrous iron (Fe2+) generates reactive oxygen species (ROS). Endolysosome stores of Fe2+ are central to iron trafficking and endolysosome deacidification releases Fe2+ into the cytoplasm. Because HERV-K Env is an arginine-rich protein that is likely endocytosed and arginine is a pH-elevating amino acid, it is important to determine HERV-K Env effects on endolysosome pH and whether HERV-K Env-induced neurotoxicity is downstream of Fe2+ released from endolysosomes. Here, we showed using SH-SY5Y human neuroblastoma cells and primary cultures of human cortical neurons (HCNs, information on age and sex was not available) that HERV-K Env (1) is endocytosed via CD98 receptors, (2) concentration dependently deacidified endolysosomes, (3) decreased endolysosome Fe2+ concentrations, (4) increased cytosolic and mitochondrial Fe2+ and ROS levels, (5) depolarized mitochondrial membrane potential, and (6) induced cell death, effects blocked by an antibody against the CD98 receptor and by the endolysosome iron chelator deferoxamine. Thus, HERV-K Env-induced increases in cytosolic and mitochondrial Fe2+ and ROS as well as cell death appear to be mechanistically caused by HERV-K Env endocytosis, endolysosome deacidification, and endolysosome Fe2+ efflux into the cytoplasm.

How I treat unique and difficult-to-manage cases of CAR T-cell therapy-associated neurotoxicity.

With growing indications for chimeric antigen receptor (CAR) T-cell therapy, toxicity profiles are evolving. There is an urgent and unmet need of approaches to optimally manage emerging adverse events that extend beyond the standard paradigm of cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome (ICANS). Although management guidelines exist for ICANS, there is little guidance on how to approach patients with neurologic comorbidities, and how to manage rare neurotoxicity presentations, such as CAR T-cell therapy-related cerebral edema, severe motor complications or late-onset neurotoxicity. In this study, we present 3 scenarios of patients treated with CAR T cells who develop unique types of neurotoxicity, and we describe an approach for the evaluation and management based on experience because objective data are limited. The goal of this study is to develop an awareness of emerging and unusual complications, discuss treatment approaches, and help institutions and health care providers establish frameworks to navigate how to best address unusual neurotoxicities to ultimately improve patient outcomes.

Efficacy and safety of cilta-cel in patients with progressive multiple myeloma after exposure to other BCMA-targeting agents.

B-cell maturation antigen (BCMA)-targeting therapies, including bispecific antibodies (BsAbs) and antibody-drug conjugates (ADCs), are promising treatments for multiple myeloma (MM), but disease may progress after their use. CARTITUDE-2 is a phase 2, multicohort study evaluating the safety and efficacy of cilta-cel, an anti-BCMA chimeric antigen receptor T therapy, in various myeloma patient populations. Patients in cohort C progressed despite treatment with a proteasome inhibitor, immunomodulatory drug, anti-CD38 antibody, and noncellular anti-BCMA immunotherapy. A single cilta-cel infusion was given after lymphodepletion. The primary end point was minimal residual disease (MRD) negativity at 10-5. Overall, 20 patients were treated (13 ADC exposed; 7 BsAb exposed; 1 in the ADC group also had prior BsAb exposure). Sixteen (80%) were refractory to prior anti-BCMA therapy. At a median follow-up of 11.3 months (range, 0.6-16.0), 7 of 20 (35%) patients were MRD negative (7 of 10 [70.0%] in the MRD-evaluable subset). Overall response rate (95% confidence interval [CI]) was 60.0% (36.1-80.9). Median duration of response and progression-free survival (95% CI) were 11.5 (7.9-not estimable) and 9.1 (1.5-not estimable) months, respectively. The most common adverse events were hematologic. Cytokine release syndrome occurred in 12 (60%) patients (all grade 1-2); 4 had immune effector cell-associated neurotoxicity syndrome (2 had grade 3-4); none had parkinsonism. Seven (35%) patients died (3 of progressive disease, 4 of adverse events [1 treatment related, 3 unrelated]). Cilta-cel induced favorable responses in patients with relapsed/refractory MM and prior exposure to anti-BCMA treatment who had exhausted other therapies. This trial was registered at www.clinicaltrials.gov as NCT04133636.

Identification of differential m6A RNA methylomes and ALKBH5 as a potential prevention target in the developmental neurotoxicity induced by multiple sevoflurane exposures.

Sevoflurane, as a commonly used inhaled anesthetic for pediatric patients, has been reported that multiple sevoflurane exposures are associated with a greater risk of developing neurocognitive disorder. N6-Methyladenosine (m6A), as the most common mRNA modification in eukaryotes, has emerged as a crucial regulator of brain function in processes involving synaptic plasticity, learning and memory, and neurodevelopment. Nevertheless, the relevance of m6A RNA methylation in the multiple sevoflurane exposure-induced developmental neurotoxicity remains mostly elusive. Herein, we evaluated the genome-wide m6A RNA modification and gene expression in hippocampus of mice that received with multiple sevoflurane exposures using m6A-sequencing (m6A-seq) and RNA-sequencing (RNA-seq). We discovered 19 genes with differences in the m6A methylated modification and differential expression in the hippocampus. Among these genes, we determined that a total of nine differential expressed genes may be closely associated with the occurrence of developmental neurotoxicity induced by multiple sevoflurane exposures. We further found that the alkB homolog 5 (ALKBH5), but not methyltransferase-like 3 (METTL3) and Wilms tumor 1-associated protein (WTAP), were increased in the hippocampus of mice that received with multiple sevoflurane exposures. And the IOX1, as an inhibitor of ALKBH5, significantly improved the learning and memory defects and reduced neuronal damage in the hippocampus of mice induced by multiple sevoflurane exposures. The current study revealed the role of m6A methylated modification and m6A-related regulators in sevoflurane-induced cognitive impairment, which might provide a novel insight into identifying biomarkers and therapeutic strategies for inhaled anesthetic-induced developmental neurotoxicity.

Need for standardization of cytokine profiling in CAR T cell therapy.

With expansion of chimeric antigen receptor (CAR) T cell therapy and broader utilization of anti-cytokine directed therapeutics for toxicity mitigation, the routine assessment of cytokines may enhance understanding of toxicity profiles, guide therapeutic interventions, and facilitate cross-trial comparisons. As specific cytokine elevations can correlate with and provide insights into CAR T cell toxicity, mitigation strategies, and response, we explored the reporting of cytokine detection methods and assessed for the correlation of cytokines to cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) across clinical trials. In this analysis, we reviewed 21 clinical trials across 60 manuscripts that featured a US Food and Drug Administration-approved CAR T cell construct or one of its predecessors. We highlight substantial variability and limited reporting of cytokine measurement platforms and panels used across CAR T cell clinical trials. Specifically, across 60 publications, 28 (46.7%) did not report any cytokine data, representing 6 of 21 (28.6%) clinical trials. In the 15 trials reporting cytokine data, at least 4 different platforms were used. Furthermore, correlation of cytokines with ICANS, CRS, and CRS severity was limited. Considering the fundamental role of cytokines in CAR T cell toxicity, our manuscript supports the need to establish standardization of cytokine measurements as a key biomarker essential to improving outcomes of CAR T cell therapy.

Decoding the neurotoxic effects of propofol: insights into the RARα-Snhg1-Bdnf regulatory cascade.

The potential neurotoxic effects of propofol, an extensively utilized anesthetic, underline the urgency to comprehend its influence on neuronal health. Insights into the role of the retinoic acid receptor-α, small nucleolar RNA host gene 1, and brain-derived neurotrophic factor (RARα-Snhg1-Bdnf) network can offer significant advancements in minimizing these effects. The study targets the exploration of the RARα and Snhg1 regulatory network's influence on Bdnf expression in the realm of propofol-induced neurotoxicity. Harnessing the Gene Expression Omnibus (GEO) database and utilizing JASPAR and RNA-Protein Interaction Prediction (RPISeq) database for projections, the study embarks on an in-depth analysis employing both in vitro and in vivo models. The findings draw a clear link between propofol-induced neurotoxicity and the amplification of RAR signaling pathways, impacting hippocampal development and apoptosis and leading to increased RARα and Snhg1 and decreased Bdnf. Propofol is inferred to accentuate neurotoxicity by heightening RARα and Snhg1 interactions, culminating in Bdnf suppression.NEW & NOTEWORTHY This study aimed to decode propofol's neurotoxic effects on the regulatory cascade, provide insights into the RARα-Snhg1-Bdnf interaction, apply extensive validation techniques, provide a detailed analysis and exploration of propofol's neurotoxicity, and offer a comprehensive approach to understanding molecular interactions.

BTBD9 attenuates manganese-induced oxidative stress and neurotoxicity by regulating insulin growth factor signaling pathway.

Manganese (Mn) is an essential mineral, but excess exposure can cause dopaminergic neurotoxicity. Restless legs syndrome (RLS) is a common neurological disorder, but the etiology and pathology remain largely unknown. The purpose of this study was to identify the role of Mn in the regulation of an RLS genetic risk factor BTBD9, characterize the function of BTBD9 in Mn-induced oxidative stress and dopaminergic neuronal dysfunction. We found that human subjects with high blood Mn levels were associated with decreased BTBD9 mRNA levels, when compared with subjects with low blood Mn levels. In A549 cells, Mn exposure decreased BTBD9 protein levels. In Caenorhabditis elegans, loss of hpo-9 (BTBD9 homolog) resulted in more susceptibility to Mn-induced oxidative stress and mitochondrial dysfunction, as well as decreased dopamine levels and alternations of dopaminergic neuronal morphology and behavior. Overexpression of hpo-9 in mutant animals restored these defects and the protection was eliminated by mutation of the forkhead box O (FOXO). In addition, expression of hpo-9 upregulated FOXO protein levels and decreased protein kinase B levels. These results suggest that elevated Mn exposure might be an environmental risk factor for RLS. Furthermore, BTBD9 functions to alleviate Mn-induced oxidative stress and neurotoxicity via regulation of insulin/insulin-like growth factor signaling pathway.

FUS-induced neurotoxicity is prevented by inhibiting GSK-3ß in a Drosophila model of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS)-linked mutations in fused in sarcoma (FUS) lead to the formation of cytoplasmic aggregates in neurons. They are believed to play a critical role in the pathogenesis of FUS-associated ALS. Therefore, the clearance and degradation of cytoplasmic FUS aggregates in neurons may be considered a therapeutic strategy for ALS. However, the molecular pathogenic mechanisms behind FUS-associated ALS remain poorly understood. Here, we report GSK-3ß as a potential modulator of FUS-induced toxicity. We demonstrated that RNAi-mediated knockdown of Drosophila ortholog Shaggy in FUS-expressing flies suppresses defective phenotypes, including retinal degeneration, motor defects, motor neuron degeneration and mitochondrial dysfunction. Furthermore, we found that cytoplasmic FUS aggregates were significantly reduced by Shaggy knockdown. In addition, we found that the levels of FUS proteins were significantly reduced by co-overexpression of Slimb, a F-box protein, in FUS-expressing flies, indicating that Slimb is critical for the suppressive effect of Shaggy/GSK-3ß inhibition on FUS-induced toxicity in Drosophila. These findings revealed a novel mechanism of neuronal protective effect through SCFSlimb-mediated FUS degradation via GSK-3ß inhibition, and provided in vivo evidence of the potential for modulating FUS-induced ALS progression using GSK-3ß inhibitors.

Arsenic-induced neurotoxicity in patients with acute promyelocytic leukaemia.

Arsenic trioxide is an essential component of therapy for acute promyelocytic leukaemia (APL) and is currently dosed on actual body weight with no upper limit. Arsenic-induced neurotoxicity is a well-recognised complication; however, there is uncertainty about its relationship to arsenic dose and obesity. We conducted a large multicentre retrospective study of 487 patients with APL treated with arsenic-based therapy across 23 sites in Australia from 2008 to 2023. The primary outcome was incidence of neurotoxicity, and secondary outcomes included relationship of neurotoxicity to obesity and cumulative arsenic dose. Any-grade neurotoxicity occurred in 113 (23%) patients, predominantly peripheral neuropathy (91%). Most events were grade 1-2 severity (85%), with grade 3 events in 12% and grade 4-5 in 3%. The incidence of neurotoxicity increased with BMI (non-obese: 16%, obesity class I: 25%, obesity class II-III: 41%; p < 0.001). On univariable analysis, obesity class I (OR 1.81, p = 0.036), obesity class II-III (OR 3.93, p < 0.001), weight >100 kg (OR 2.72, p < 0.001), daily arsenic trioxide dose >15 mg (OR 5.05, p < 0.001) and cumulative induction dose >500 mg (OR 3.95, p < 0.001) were all significantly associated with neurotoxicity. Obesity class II-III and induction dose >500 mg remained significant on multivariable analysis. Our study highlights the strong association between BMI, arsenic trioxide dose and neurotoxicity. Pre-emptive dose reductions should be considered for obese patients receiving high doses of arsenic.

Older age, CNS leukaemic involvement and induction tumour lysis increases the risk of methotrexate (MTX)-induced neurotoxicity in childhood acute lymphoblastic leukaemia/lymphoma: Experience from a tertiary care centre in South India.

Methotrexate (MTX), although an indispensable part of contemporary treatment protocols for childhood acute lymphoblastic leukaemia (ALL)/lymphomas (LBL) in improving outcomes, can lead to serious neurotoxicity with long-term consequences. The aetiopathogenesis, predisposing factors and treatment for MTX-induced neurotoxicity are not yet well defined. The aim of our study was to detect the incidence, risk factors and to assess the overall outcomes of MTX-induced neurotoxicity among large cohort of paediatric ALL/LBL patients treated on a uniform protocol. We conducted retrospective audit of medical records of 622 consecutive children (≤14 years) diagnosed with ALL and LBL between January 2018 and December 2022 and treated on modified BFM-95 protocol at the Department of Pediatric Oncology, Regional Cancer Centre, Thiruvananthapuram. Risk factors predisposing to MTX-induced neurotoxicity were identified using binary logistic regression analysis. Forty-three children were diagnosed with MTX-induced neurotoxicity with an incidence rate of 6.9%. More than two-thirds of them had high-grade MTX-induced neurotoxicity CTCAE v5.0 with a median age of 9 years (range: 9 months to 14 years). Almost half of them developed MTX neurotoxicity during Protocol M followed by Phase-Ib consolidation (15%). Majority of these patients (84%, 36/43) were challenged again with MTX, with 11% (4/36) developing recurrence. Fifteen per cent had persistent neurological deficits at last follow-up. Univariate analysis found older age (age > 5 years) (p < 0.001), T-cell phenotype (p = 0.040), tumour lysis syndrome during induction (p < 0.001), baseline renal problems prior to MTX exposure (p < 0.001) and CNS leukaemic involvement (p < 0.003) to be significantly associated with MTX neurotoxicity. On multivariate analysis, older age (>5 years), tumour lysis during induction and CNS leukaemia retained statistical significance (p < 0.05). Methotrexate-induced neurotoxicity during paediatric acute lymphoblastic leukaemia/lymphoma therapy is a transient phenomenon in majority and re-challenge with MTX is generally safe. Older age children who develop tumour lysis during induction and CNS leukaemic involvement are at increased risk for MTX-induced neurotoxicity during ALL/LBL treatment.

Non-cytotoxic nanomolar concentration of arctigenin protects neuronal cells from chemotherapy-induced ferroptosis by regulating SLC7A11-cystine-cysteine axis.

Neurotoxicity is a common side effect of certain types of therapeutic drugs, posing a major hurdle for their clinical application. Accumulating evidence suggests that ferroptosis is involved in the neurotoxicity induced by these drugs. Therefore, targeting ferroptosis is considered to be a reasonable approach to prevent such side effect. Arctigenin (ATG) is a major bioactive ingredient of Arctium lappa L., a popular medicinal plant in Asia, and has been reported to have multiple bioactivities including neuroprotection. However, the mechanisms underlying the neuroprotection of ATG has not been well elucidated. The purpose of this study was to investigate whether the neuroprotection of ATG was associated with its ability to protect neuronal cells from ferroptosis. Using neuronal cell ferroptosis model induced by either classic ferroptosis induces or therapeutic drugs, we demonstrated for the first time that ATG in the nanomolar concentration range effectively prevented neuronal cell ferroptosis induced by classic ferroptosis inducer sulfasalazine (SAS) and erastin (Era), or therapeutic drug oxaliplatin (OXA) and 5-fluorouracil (5-FU). Mechanistically, we uncovered that the anti-ferroptotic effect of ATG was attributed to its ability to activate SLC7A11-cystine-cysteine axis. The findings of the present study implicate that ATG holds great potential to be developed as a novel agent for preventing SLC7A11 inhibition-mediated neurotoxicity.

Associations of granulocyte colony-stimulating factor with toxicities and efficacy of chimeric antigen receptor T-cell therapy in relapsed or refractory B-cell acute lymphoblastic leukemia.

Few studies have reported the associations of granulocyte colony-stimulating factor (G-CSF) with cytokine release syndrome (CRS), neurotoxic events (NEs) and efficacy after chimeric antigen receptor (CAR) T-cell therapy for relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). We present a retrospective study of 67 patients with R/R B-ALL who received anti-CD19 CAR T-cell therapy, 41 (61.2%) patients received G-CSF (G-CSF group), while 26 (38.8%) did not (non-G-CSF group). Patients had similar duration of grade 3-4 neutropenia between the two groups. The incidences of CRS and NEs were higher in G-CSF group, while no differences in severity were found. Further stratified analysis showed that the incidence and severity of CRS were not associated with G-CSF administration in patients with low bone marrow (BM) tumor burden. None of the patients with low BM tumor burden developed NEs. However, there was a significant increase in the incidence of CRS after G-CSF administration in patients with high BM tumor burden. The duration of CRS in patients who used G-CSF was longer. There were no significant differences in response rates at 1 and 3 months after CAR T-cell infusion, as well as overall survival (OS) between the two groups. In conclusion, our results showed that G-CSF administration was not associated with the incidence or severity of CRS in patients with low BM tumor burden, but the incidence of CRS was higher after G-CSF administration in patients with high BM tumor burden. The duration of CRS was prolonged in G-CSF group. G-CSF administration was not associated with the efficacy of CAR T-cell therapy.

Parkinson's disease-derived α-synuclein assemblies combined with chronic-type inflammatory cues promote a neurotoxic microglial phenotype.

Parkinson's disease (PD) is a common age-related neurodegenerative disorder characterized by the aggregation of α-Synuclein (αSYN) building up intraneuronal inclusions termed Lewy pathology. Mounting evidence suggests that neuron-released αSYN aggregates could be central to microglial activation, which in turn mounts and orchestrates neuroinflammatory processes potentially harmful to neurons. Therefore, understanding the mechanisms that drive microglial cell activation, polarization and function in PD might have important therapeutic implications. Here, using primary microglia, we investigated the inflammatory potential of pure αSYN fibrils derived from PD patients. We further explored and characterized microglial cell responses to a chronic-type inflammatory stimulation combining PD patient-derived αSYN fibrils (FPD), Tumor necrosis factor-α (TNFα) and prostaglandin E2 (PGE2) (TPFPD). We showed that FPD hold stronger inflammatory potency than pure αSYN fibrils generated de novo. When combined with TNFα and PGE2, FPD polarizes microglia toward a particular functional phenotype departing from FPD-treated cells and featuring lower inflammatory cytokine and higher glutamate release. Whereas metabolomic studies showed that TPFPD-exposed microglia were closely related to classically activated M1 proinflammatory cells, notably with similar tricarboxylic acid cycle disruption, transcriptomic analysis revealed that TPFPD-activated microglia assume a unique molecular signature highlighting upregulation of genes involved in glutathione and iron metabolisms. In particular, TPFPD-specific upregulation of Slc7a11 (which encodes the cystine-glutamate antiporter xCT) was consistent with the increased glutamate response and cytotoxic activity of these cells toward midbrain dopaminergic neurons in vitro. Together, these data further extend the structure-pathological relationship of αSYN fibrillar polymorphs to their innate immune properties and demonstrate that PD-derived αSYN fibrils, TNFα and PGE2 act in concert to drive microglial cell activation toward a specific and highly neurotoxic chronic-type inflammatory phenotype characterized by robust glutamate release and iron retention.

In situ PEGylation of CAR T cells alleviates cytokine release syndrome and neurotoxicity.

Chimeric antigen receptor T (CAR T) cell immunotherapy is successful at treating many cancers. However, it often induces life-threatening cytokine release syndrome (CRS) and neurotoxicity. Here, we show that in situ conjugation of polyethylene glycol (PEG) to the surface of CAR T cells ('PEGylation') creates a polymeric spacer that blocks cell-to-cell interactions between CAR T cells, tumour cells and monocytes. Such blockage hinders intensive tumour lysing and monocyte activation by CAR T cells and, consequently, decreases the secretion of toxic cytokines and alleviates CRS-related symptoms. Over time, the slow expansion of CAR T cells decreases PEG surface density and restores CAR T cell-tumour-cell interactions to induce potent tumour killing. This occurs before the restoration of CAR T cell-monocyte interactions, opening a therapeutic window for tumour killing by CAR T cells before monocyte overactivation. Lethal neurotoxicity is also lower when compared with treatment with the therapeutic antibody tocilizumab, demonstrating that in situ PEGylation of CAR T cells provides a materials-based strategy for safer cellular immunotherapy.

Employing a Toxic Aging Coin approach to assess hexavalent chromium (Cr[VI])-induced neurotoxic effects on behavior: Heads for age differences.

We are facing a rapidly growing geriatric population (65+) that will live for multiple decades and are challenged with environmental pollution far exceeding that of previous generations. Consequently, we currently have a poor understanding of how environmental pollution will impact geriatric health distinctly from younger populations. Few toxicology studies have considered age differences with geriatric individuals. Critically, all top ten most prevalent age-related diseases are linked to metal exposures. Hexavalent chromium [Cr(VI)] is a metal of major environmental health concern that can induce aging phenotypes and neurotoxicity. However, there are many knowledge gaps for Cr(VI) neurotoxicity, including how Cr(VI) impacts behavior. To address this, we exposed male rats across three ages (3-, 7-, and 18-months old) to Cr(VI) in drinking water (0, 0.05, 0.1 mg/L) for 90 days. These levels reflect the maximum contaminant levels determined by the World Health Organization (WHO) and the U.S. Environmental Protection Agency (US EPA). Here, we report how these Cr(VI) drinking water levels impacted rat behaviors using a battery of behavior tests, including grip strength, open field assay, elevated plus maze, Y-maze, and 3-chamber assay. We observed adult rats were the most affected age group and memory assays (spatial and social) exhibited the most significant effects. Critically, the significant effects were surprising as rats should be particularly resistant to these Cr(VI) drinking water levels due to the adjustments applied in risk assessment from rodent studies to human safety, and because rats endogenously synthesize vitamin C in their livers (vitamin C is a primary reducer of Cr[VI] to Cr[III]). Our results emphasize the need to broaden the scope of toxicology research to consider multiple life stages and suggest the current regulations for Cr(VI) in drinking water need to be revisited.

Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT): A Preventable Cerebellar Disorder.

We report a case study of a 60-year-old man with bipolar disorder on stable lithium treatment who developed severe toxicity while admitted to ICU with sepsis and multiorgan failure. Despite unchanged lithium administration, his serum levels escalated due to renal dysfunction, resulting in lithium toxicity. After regaining consciousness, he exhibited a cerebellar syndrome marked by ataxia, tremor, and scanning speech. MRI revealed cerebellar atrophy. Following discontinuation of lithium and hemodialysis, the patient's symptoms remained static. The patient was diagnosed with syndrome of irreversible lithium-effectuated neurotoxicity (SILENT), a chronic cerebellar disorder characterized by persistent ataxia, nystagmus, and gait abnormalities extending beyond two months post-lithium exposure. The disorder has a predilection for cerebellar and basal ganglia dysfunction. MRI findings include cerebellar gliosis and atrophy and leptomeningeal enhancement. This case report highlights that SILENT is both preventable and permanent, urging heightened awareness among clinicians to facilitate early detection and intervention. Patients on lithium with compromised renal function or fever necessitate vigilant lithium level monitoring, dose adjustment, or cessation, to forestall enduring morbidity. This case emphasizes the significance of recognizing and managing SILENT, particularly in critical care settings, to mitigate long-term cerebellar impairment and optimize patient outcomes.