The foam cell-derived exosomal miRNA Novel-3 drives neuroinflammation and ferroptosis during ischemic stroke.

Large artery atherosclerosis (LAA) is a prevalent cause of acute ischemic stroke (AIS). Understanding the mechanisms linking atherosclerosis to stroke is essential for developing appropriate intervention strategies. Here, we found that the exosomal miRNA Novel-3 is selectively upregulated in the plasma of patients with LAA-AIS. Notably, Novel-3 was predominantly expressed in macrophage-derived foam cells, and its expression correlated with atherosclerotic plaque vulnerability in patients undergoing carotid endarterectomy. Exploring the function of Novel-3 in a mouse model of cerebral ischemia, we found that Novel-3 exacerbated ischemic injury and targeted microglia and macrophages expressing ionized calcium-binding adapter molecule 1 in peri-infarct regions. Mechanistically, Novel-3 increased ferroptosis and neuroinflammation by interacting with striatin (STRN) and downregulating the phosphoinositide 3-kinase-AKT-mechanistic target of rapamycin signaling pathway. Blocking Novel-3 activity or overexpressing STRN provided neuroprotection under ischemic conditions. Our findings suggest that exosomal Novel-3, which is primarily derived from macrophage-derived foam cells, targets microglia and macrophages in the brain to induce neuroinflammation and could serve as a potential therapeutic target for patients with stroke who have atherosclerosis.

Systematic Druggable Genome-Wide Mendelian Randomization Identifies Therapeutic Targets for Functional Outcome After Ischemic Stroke.

BACKGROUND: Stroke is a leading cause of death worldwide, with a lack of effective treatments for improving the prognosis. The aim of the present study was to identify novel therapeutic targets for functional outcome after ischemic stroke . METHODS AND RESULTS: Cis-expression quantitative trait loci data for druggable genes were used as instrumental variables. The primary outcome was the modified Rankin Scale score at 3 months after ischemic stroke, evaluated as a dichotomous variable (3-6 versus 0-2) and also as an ordinal variable. Drug target Mendelian randomization, Steiger filtering analysis, and colocalization analysis were performed. Additionally, phenome-wide Mendelian randomization analysis was performed to identify the safety of the drug target genes at the genetic level. Among >2600 druggable genes, genetically predicted expression of 16 genes (ABCC2, ATRAID, BLK, CD93, CHST13, NR1H3, NRBP1, PI3, RIPK4, SEMG1, SLC22A4, SLC22A5, SLCO3A1, TEK, TLR4, and WNT10B) demonstrated the causal associations with ordinal modified Rankin Scale (P<1.892×10-5) or poor functional outcome (modified Rankin Scale 3-6 versus 0-2, P<1.893×10-5). Steiger filtering analysis suggested potential directional stability (P<0.05). Colocalization analysis provided further support for the associations between genetically predicted expression of ABCC2, NRBP1, PI3, and SEMG1 with functional outcome after ischemic stroke. Furthermore, phenome-wide Mendelian randomization revealed additional beneficial indications and few potential safety concerns of therapeutics targeting ABCC2, NRBP1, PI3, and SEMG1, but the robustness of these results was limited by low power. CONCLUSIONS: The present study revealed 4 candidate therapeutic targets for improving functional outcome after ischemic stroke, while the underlying mechanisms need further investigation.

Single-cell analysis of anti-BCMA CAR T cell therapy in patients with central nervous system autoimmunity.

Chimeric antigen receptor (CAR) T cell immunotherapy for the treatment of neurological autoimmune diseases is promising, but CAR T cell kinetics and immune alterations after treatment are poorly understood. Here, we performed single-cell multi-omics sequencing of paired cerebrospinal fluid (CSF) and blood samples from patients with neuromyelitis optica spectrum disorder (NMOSD) treated with anti-B cell maturation antigen (BCMA) CAR T cells. Proliferating cytotoxic-like CD8+ CAR T cell clones were identified as the main effectors in autoimmunity. Anti-BCMA CAR T cells with enhanced features of chemotaxis efficiently crossed the blood-CSF barrier, eliminated plasmablasts and plasma cells in the CSF, and suppressed neuroinflammation. The CD44-expressing early memory phenotype in infusion products was potentially associated with CAR T cell persistence in autoimmunity. Moreover, CAR T cells from patients with NMOSD displayed distinctive features of suppressed cytotoxicity compared with those from hematological malignancies. Thus, we provide mechanistic insights into CAR T cell function in patients with neurological autoimmune disease.

Ldl-stimulated microglial activation exacerbates ischemic white matter damage.

The role of microglia in triggering the blood-brain barrier (BBB) impairment and white matter damage after chronic cerebral hypoperfusion is unclear. Here we demonstrated that the vessel-adjacent microglia were specifically activated by the leakage of plasma low-density lipoprotein (LDL), which led to BBB breakdown and ischemic demyelination. Interestingly, we found that LDL stimulation enhanced microglial phagocytosis, causing excessive engulfment of myelin debris and resulting in an overwhelming lipid burden in microglia. Surprisingly, these lipid-laden microglia exhibited a suppressed profile of inflammatory response and compromised pro-regenerative properties. Microglia-specific knockdown of LDLR or systematic medication lowering circulating LDL-C showed protective effects against ischemic demyelination. Overall, our findings demonstrated that LDL-stimulated vessel-adjacent microglia possess a disease-specific molecular signature, characterized by suppressed regenerative properties, which is associated with the propagation of demyelination during ischemic white matter damage.

B cell lineage reconstitution underlies CAR-T cell therapeutic efficacy in patients with refractory myasthenia gravis.

B-cell maturation antigen (BCMA), expressed in plasmablasts and plasma cells, could serve as a promising therapeutic target for autoimmune diseases. We reported here chimeric antigen receptor (CAR) T cells targeting BCMA in two patients with highly relapsed and refractory myasthenia gravis (one with AChR-IgG, and one with MuSk-IgG). Both patients exhibited favorable safety profiles and persistent clinical improvements over 18 months. Reconstitution of B-cell lineages with sustained reduced pathogenic autoantibodies might underlie the therapeutic efficacy. To identify the possible mechanisms underlying the therapeutic efficacy of CAR-T cells in these patients, longitudinal single-cell RNA and TCR sequencing was conducted on serial blood samples post infusion as well as their matching infusion products. By tracking the temporal evolution of CAR-T phenotypes, we demonstrated that proliferating cytotoxic-like CD8 clones were the main effectors in autoimmunity, whereas compromised cytotoxic and proliferation signature and profound mitochondrial dysfunction in CD8+ Te cells before infusion and subsequently defect CAR-T cells after manufacture might explain their characteristics in these patients. Our findings may guide future studies to improve CAR T-cell immunotherapy in autoimmune diseases.

Causal association between the peripheral immunity and the risk and disease severity of multiple sclerosis.

Background: Growing evidence links immunological responses to Multiple sclerosis (MS), but specific immune factors are still unclear. Methods: Mendelian randomization (MR) was performed to investigate the association between peripheral hematological traits, MS risk, and its severity. Then, further subgroup analysis of immune counts and circulating cytokines and growth factors were performed. Results: MR revealed higher white blood cell count (OR [95%CI] = 1.26 [1.10,1.44], P = 1.12E-03, P adjust = 3.35E-03) and lymphocyte count (OR [95%CI] = 1.31 [1.15,1.50], P = 5.37E-05, P adjust = 3.22E-04) increased the risk of MS. In further analysis, higher T cell absolute count (OR [95%CI] = 2.04 [1.36,3.08], P = 6.37E-04, P adjust = 2.19E-02) and CD4+ T cell absolute count (OR [95%CI] = 2.11 [1.37,3.24], P = 6.37E-04, P adjust = 2.19E-02), could increase MS risk. While increasing CD25++CD4+ T cell absolute count (OR [95%CI] = 0.75 [0.66,0.86], P = 2.12E-05, P adjust = 1.72E-03), CD25++CD4+ T cell in T cell (OR [95%CI] = 0.79[0.70,0.89], P = 8.54E-05, P adjust = 5.29E-03), CD25++CD4+ T cell in CD4+ T cell (OR [95%CI] = 0.80[0.72,0.89], P = 1.85E-05, P adjust = 1.72E-03), and CD25++CD8+ T cell in T cell (OR [95%CI] = 0.68[0.57,0.81], P = 2.22E-05, P adjust = 1.72E-03), were proved to be causally defensive for MS. For the disease severity, the suggestive association between some traits related to CD4+ T cell, Tregs and MS severity were demonstrated. Moreover, elevated levels of IL-2Ra had a detrimental effect on the risk of MS (OR [95%CI] = 1.22 [1.12,1.32], P = 3.20E-06, P adjust = 1.34E-04). Conclusions: This study demonstrated a genetically predicted causal relationship between elevated peripheral immune cell counts and MS. Subgroup analysis revealed a specific contribution of peripheral immune cells, holding potential for further investigations into the underlying mechanisms of MS and its severity.

Single-cell analysis of refractory anti-SRP necrotizing myopathy treated with anti-BCMA CAR-T cell therapy.

Immune-mediated necrotizing myopathy (IMNM) is an autoimmune disorder associated with the presence of autoantibodies, characterized by severe clinical presentation with rapidly progressive muscular weakness and elevated levels of creatine kinase, while traditional pharmacological approaches possess varying and often limited effects. Considering the pathogenic role of autoantibodies, chimeric antigen receptor (CAR)-T cells targeting B cell maturation antigen (BCMA) have emerged as a promising therapeutic strategy. We reported here a patient with anti-signal recognition particle IMNM refractory to multiple available therapies, who was treated with BCMA-targeting CAR-T cells, exhibited favorable safety profiles, sustained reduction in pathogenic autoantibodies, and persistent clinical improvements over 18 mo. Longitudinal single-cell RNA, B cell receptor, T cell receptor sequencing analysis presented the normalization of immune microenvironment after CAR-T cell infusion, including reconstitution of B cell lineages, replacement of T cell subclusters, and suppression of overactivated immune cells. Analysis on characteristics of CAR-T cells in IMNM demonstrated a more active expansion of CD8+ CAR-T cells, with a dynamic phenotype shifting pattern similar in CD4+ and CD8+ CAR-T cells. A comparison of CD8+ CAR-T cells in patients with IMNM and those with malignancies collected at different timepoints revealed a more NK-like phenotype with enhanced tendency of cell death and neuroinflammation and inhibited proliferating ability of CD8+ CAR-T cells in IMNM while neuroinflammation might be the distinct characteristics. Further studies are warranted to define the molecular features of CAR-T cells in autoimmunity and to seek higher efficiency and longer persistence of CAR-T cells in treating autoimmune disorders.

Soluble TREM2 triggers microglial dysfunction in neuromyelitis optica spectrum disorders.

Microglia-mediated neuroinflammation contributes to acute demyelination in neuromyelitis optica spectrum disorders (NMOSD). Soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in the CSF has been associated with microglial activation in several neurodegenerative diseases. However, the basis for this immune-mediated attack and the pathophysiological role of sTREM2 in NMOSD remain to be elucidated. Here, we performed Mendelian randomization analysis and identified a genetic association between increased CSF sTREM2 and NMOSD risk. CSF sTREM2 was elevated in patients with NMOSD and was positively correlated with neural injury and other neuroinflammation markers. Single-cell RNA sequencing of human macrophage/microglia-like cells in CSF, a proxy for microglia, showed that increased CSF sTREM2 was positively associated with microglial dysfunction in patients with NMOSD. Furthermore, we demonstrated that sTREM2 is a reliable biomarker of microglial activation in a mouse model of NMOSD. Using unbiased transcriptomic and lipidomic screens, we identified that excessive activation, overwhelmed phagocytosis of myelin debris, suppressed lipid metabolism and enhanced glycolysis underlie sTREM2-mediated microglial dysfunction, possibly through the nuclear factor kappa B (NF-κB) signalling pathway. These molecular and cellular findings provide a mechanistic explanation for the genetic association between CSF sTREM2 and NMOSD risk and indicate that sTREM2 could be a potential biomarker of NMOSD progression and a therapeutic target for microglia-mediated neuroinflammation.

TREM2-IGF1 Mediated Glucometabolic Enhancement Underlies Microglial Neuroprotective Properties During Ischemic Stroke.

Microglia, the major resident immune cells in the central nervous system, serve as the frontline soldiers against cerebral ischemic injuries, possibly along with metabolic alterations. However, signaling pathways involved in the regulation of microglial immunometabolism in ischemic stroke remain to be further elucidated. In this study, using single-nuclei RNA sequencing, a microglial subcluster up-regulated in ischemic brain tissues is identified, with high expression of Igf1 and Trem2, neuroprotective transcriptional signature and enhanced oxidative phosphorylation. Microglial depletion by PLX3397 exacerbates ischemic brain damage, which is reversed by repopulating the microglia with high Igf1 and Trem2 phenotype. Mechanistically, Igf1 serves as one of the major down-stream molecules of Trem2, and Trem2-Igf1 signaling axis regulates microglial functional and metabolic profiles, exerting neuroprotective effects on ischemic stroke. Overexpression of Igf1 and supplementation of cyclocreatine restore microglial glucometabolic levels and cellular functions even in the absence of Trem2. These findings suggest that Trem2-Igf1 signaling axis reprograms microglial immunometabolic profiles and shifts microglia toward a neuroprotective phenotype, which has promising therapeutic potential in treating ischemic stroke.

Modulation of microglial metabolism facilitates regeneration in demyelination.

Microglia exhibit diverse phenotypes in various central nervous system disorders and metabolic pathways exert crucial effects on microglial activation and effector functions. Here, we discovered two novel distinct microglial clusters, functionally associated with enhanced phagocytosis (PEMs) and myelination (MAMs) respectively, in human patients with multiple sclerosis by integrating public snRNA-seq data. Microglia adopt a PEMs phenotype during the early phase of demyelinated lesions, predominated in pro-inflammatory responses and aggravated glycolysis, while MAMs mainly emerged during the later phase, with regenerative signatures and enhanced oxidative phosphorylation. In addition, microglial triggering receptor expressed on myeloid cells 2 (Trem2) was greatly involved in the phenotype transition in demyelination, but not indispensable for microglia transition toward PEMs. Rosiglitazone could promote microglial phenotype conversion from PEMs to MAMs, thus favoring myelin repair. Taken together, these findings provide insights into therapeutic interventions targeting immunometabolism to switch microglial phenotypes and facilitate regenerative capacity in demyelination.

Haste makes waste: staged suppression of autophagic-lysosomal pathway in microglia promotes the efficient clearance of myelin debris.

The autophagic-lysosomal pathway of microglia plays a key role in myelin debris removal in white matter damage. As the lipid-rich myelin debris are engulfed by microglia, the cellular autophagic level increases, accompanied by lysosomal dysfunction. However, several issues such as how to regulate this pathway to ensure the effective degradation of myelin debris, and maintain the balance of lipid metabolism are still to be elucidated. Recently, we have demonstrated that the excessive activation of macroautophagy/autophagy leads to lipid overload in lysosomes and lipid droplets accumulation, which could be the initiator of microglial dysfunction and secondary inflammatory white matter damage. Interestingly, staged suppression of autophagic activation in the acute phase of demyelination could benefit microglia allowing them to regain the lipid metabolism balance, and reduce the excessive accumulation of lipids, thus promoting the removal of myelin debris. The neuroprotective effects of microglial autophagy regulation may be related to intracellular linoleic acid (LA) production and PPARG pathway activation.

Anti-BCMA CAR T-cell therapy CT103A in relapsed or refractory AQP4-IgG seropositive neuromyelitis optica spectrum disorders: phase 1 trial interim results.

Chimeric antigen receptor (CAR) T-cell therapy that targets B-cell maturation antigen (BCMA) have great potentials in autoimmune diseases and could be novel therapeutics for relapsed/refractory neuromyelitis optica spectrum disorder (NMOSD). To evaluate the safety and efficacy of the CT103A, a self-developed BCMA-targeting CAR construct against BCMA, in patients with AQP4-IgG seropositive NMOSD, an ongoing, investigator-initiated, open-label, single-arm, phase 1 clinical trial is conducted at our center. In total, 12 patients were administered with a CAR-BCMA infusion. Ten of the 12 patients dosed were women (83.3%), with a median age of 49.5 years (range, 30-67). were The most common events of grade 3 or higher were hematologic toxic effects. Seven patients (58%) developed infections, but no grade 4 infections occurred. Cytokine release syndrome was reported in all patients with only events of grade 1 or 2 observed. During the follow-up of a median 5.5 months, 11 patients had no relapse; all patients generally reported improvement in disabilities and quality-of-life outcomes; 11 patients' AQP-4 antibodies in serum showed a downward trend by the cutoff date. CAR T-cell expansion was associated with responses, and persisted more than 6 months post-infusion in 17% of the patients. In summary, CAR T-cell therapy shows a manageable safety profile and therapeutic potentials for patients with relapsed/refractory AQP4-IgG seropositive NMOSD. Another expansion phase is currently underway to determine the safety and efficacy of CAR T-BCMA infusion in patients with other neuro-inflammatory diseases.

Staged suppression of microglial autophagy facilitates regeneration in CNS demyelination by enhancing the production of linoleic acid.

Microglia play a critical role in the clearance of myelin debris, thereby ensuring functional recovery from neural injury. Here, using mouse model of demyelination following two-point LPC injection, we show that the microglial autophagic-lysosomal pathway becomes overactivated in response to severe demyelination, leading to lipid droplet accumulation and a dysfunctional and pro-inflammatory microglial state, and finally failed myelin debris clearance and spatial learning deficits. Data from genetic approaches and pharmacological modulations, via microglial Atg5 deficient mice and intraventricular BAF A1 administration, respectively, demonstrate that staged suppression of excessive autophagic-lysosomal activation in microglia, but not sustained inhibition, results in better myelin debris degradation and exerts protective effects against demyelination. Combined multi-omics results in vitro further showed that enhanced lipid metabolism, especially the activation of the linoleic acid pathway, underlies this protective effect. Supplementation with conjugated linoleic acid (CLA), both in vivo and in vitro, could mimic these effects, including attenuating inflammation and restoring microglial pro-regenerative properties, finally resulting in better recovery from demyelination injuries and improved spatial learning function, by activating the peroxisome proliferator-activated receptor (PPAR-γ) pathway. Therefore, we propose that pharmacological inhibition targeting microglial autophagic-lysosomal overactivation or supplementation with CLA could represent a potential therapeutic strategy in demyelinated disorders.

CSF sTREM2 in neurological diseases: a two-sample Mendelian randomization study.

BACKGROUND: Soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in cerebrospinal fluid (CSF) has been described as a biomarker for microglial activation, which were observed increased in a variety of neurological disorders. OBJECTIVE: Our objective was to explore whether genetically determined CSF sTREM2 levels are causally associated with different neurological diseases by conducting a two-sample Mendelian randomization (MR) study. METHODS: Single nucleotide polymorphisms significantly associated with CSF sTREM2 levels were selected as instrumental variables to estimate the causal effects on clinically common neurological diseases, including stroke, Alzheimer's diseases, Parkinson's diseases, amyotrophic lateral sclerosis, multiple sclerosis, and epilepsy and their subtypes. Summary-level statistics of both exposure and outcomes were applied in an MR framework. RESULTS: Genetically predicted per 1 pg/dL increase of CSF sTREM2 levels was associated with higher risk of multiple sclerosis (OR = 1.038, 95%CI = 1.014-1.064, p = 0.002). Null association was found in risk of other included neurological disorders. CONCLUSIONS: These findings provide support for a potential causal relationship between elevated CSF sTREM2 levels and higher risk of multiple sclerosis.

Two sets of acupoint combination of similar functions engage shared neural representation: a functional magnetic resonance imaging study.

OBJECTIVE: To investigate whether the neural representations underlying alternating two acupoint combinations (ACs) are the same or not. METHODS: In this functional magnetic resonance imaging study, two sets of analgesia ACs were utilized, including Waiguan (TE5) and Qiuxu (GB40) for Group A, and Neiguan (PC6) and Taichong (LR3) for Group B, which are the most commonly adopted in clinical treatment. Each group had 20 healthy subjects. An experimental design was proposed, which consisted of a pre-needling resting phase, a needling phase and a post-needling resting phase. This paradigm optimally mimics the clinical protocol as well as focuses on both the stimulation and the resting periods. The results were subjected to general linear model analysis, conjunction analysis and the functional connectivity analysis. RESULTS: The rostral anterior cingulated cortex was engaged in the initiative period of the acupuncture effect in both groups, and it was chosen as the seed region for the functional connectivity analysis for the following resting period. The results showed that several shared brain regions were involved in both groups, in particular the insula, amygdala and hypothalamus. Moreover, significant differences were located at the posterior cingulated cortex as revealed by a two sample -test (P<0.05, corrected). Other regions showed no significant differences. This finding was further supported by the spatial correlation analysis that the two groups were significantly correlated (r =0.51, P<0.01). CONCLUSION: This preliminary research helps us understand the neurophysiological mechanisms of acupuncture when following clinical guidelines on ACs, as well as provides an important opportunity to develop better treatment strategies for reducing, or even preventing pain.

The role of dorsal anterior cingulate cortex in the regulation of craving by reappraisal in smokers.

RATIONALE AND OBJECTIVE: Drug cues can induce craving for drugs of abuse. Dysfunctional regulation of emotion and motivation regarding rewarding objects appears to be an integral part of addiction. It has been found that cognitive strategies decreased the intensity of craving in addicts. Reappraisal strategy is a type of cognitive strategy that requires participants to reinterpret the meaning of an emotional situation. In addition, studies have found that activation of the dorsal anterior cingulate cortex (dACC) is associated with the selection and application of cognitive reappraisal. In present study, we sought to determine whether such cognitive regulation engages the dACC and improves inhibition of craving in smokers. METHODS: Sixteen smokers underwent functional magnetic resonance imaging (fMRI) during performance of a cigarette reward-conditioning procedure with cognitive reappraisal. We focused our analyses on the dACC as a key structure of cognitive control of craving. Cue induced craving under different conditions was obtained. Correlational analysis between the functional response in the dACC and the subjective craving was performed. RESULTS: We found that using a cognitive reappraisal was successful in decreasing the conditioned craving. Right dACC (BA 24/32) engaged in the cognitive reappraisal. In addition, the individual's subjective craving was negatively correlated with the right dACC activation. CONCLUSIONS: These findings suggest that the dACC are important substrates of Inhibition of cue induced craving in smokers. Cognitive regulation by cognitive reappraisal may help addicted individuals avoid the anticipated situations where they are exposed to conditioned cues.

[Application of 3D-CT angiography in the diagnosis and post-operative evaluation of intracranial aneurysms].

OBJECTIVE: To assess the values of three-dimensional CT (3D-CT) angiography (3D-CTA) in the diagnosis and operative follow up of intracranial aneurysms after clip. METHODS: 3D-CTA and DSA were performed on 32 patients with clinical manifestations suggestive of harboring intracranial aneurysms. DSA and operation were regarded as gold standards. Five patients who had been treated with clip underwent CTA both preoperatively and postoperatively to evaluate the effects of aneurysm clipping. RESULTS: According to DSA results and surgical findings, the sensitivity, specificity, and the accuracy of 3D-CTA for the detection of aneurysms were 100%, 100%, and 93.9% respectively. The detection rate of aneurysm with a diameter<3 mm of CTA, with the smallest diameter of 2 mm, was higher than that of DSA, however, there was no significant difference in the detection rate of aneurysm with the diameter>3 mm between CTA and DSA. Postoperative CTA displayed a remnant of aneurysm body in one case. CONCLUSION: With satisfying sensitivity and specificity, 3D-CTA is a quick, reliable, and relatively noninvasive diagnostic tool for intracranial aneurysms. 3D-CTA combined with VR delineates the aneurysmal morphology in detail, and provides useful information for choosing and planning microsurgical or endovascular treatment.