Attenuated Disease Severity Research Articles

Inflammatory Markers and Severity in COVID-19 Patients with Clostridioides Difficile Co-Infection: A Retrospective Analysis Including Subgroups with Diabetes, Cancer, and Elderly.

The interplay of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and Clostridioides difficile infection (CDI) poses a critical clinical challenge. The resultant inflammatory milieu and its impact on outcomes remain incompletely understood, especially among vulnerable subgroups such as elderly patients, those with diabetes, and individuals with cancer. This study aimed to characterize inflammatory markers and composite inflammatory severity scores-such as Acute Physiology and Chronic Health Evaluation II (APACHE II), Confusion, Urea, Respiratory rate, Blood pressure, and age ≥ 65 years (CURB-65), National Early Warning Score (NEWS), and the Systemic Immune-Inflammation Index (SII)-in hospitalized Coronavirus Disease 2019 (COVID-19) patients with and without CDI, and to evaluate their prognostic implications across key clinical subgroups. We conducted a retrospective, single-center study of 240 hospitalized adults with Reverse Transcription Polymerase Chain Reaction (RT-PCR)-confirmed COVID-19 between February 2021 and March 2023. Of these, 98 had concurrent CDI. We collected baseline demographics, comorbidities, and laboratory parameters including C-reactive protein (CRP), Interleukin-6 (IL-6), ferritin, neutrophil and lymphocyte counts, albumin, platelet counts, and calculated indices (C-reactive protein to Albumin Ratio (CAR), Neutrophil-to-Lymphocyte Ratio (NLR), Prognostic Nutritional Index (PNI), SII). Patients were stratified by CDI status and analyzed for inflammatory marker distributions, severity scores (APACHE II, CURB-65, NEWS), and outcomes (Intensive Care Unit (ICU) admission, mechanical ventilation, mortality). Subgroup analyses included diabetes, elderly (≥65 years), and cancer patients. Statistical comparisons employed t-tests, chi-square tests, and logistic regression models. Patients with CDI demonstrated significantly higher CRP, IL-6, SII, and CAR, coupled with lower albumin and PNI (p < 0.05). They also had elevated APACHE II, CURB-65, and NEWS scores. CDI-positive patients experienced increased ICU admission (38.8% vs. 20.5%), mechanical ventilation (24.5% vs. 12.9%), and mortality (22.4% vs. 10.6%, all p < 0.05). Subgroup analyses revealed more pronounced inflammatory derangements and worse outcomes in elderly, diabetic, and cancer patients with CDI. Concurrent CDI intensifies systemic inflammation and adverse clinical trajectories in hospitalized COVID-19 patients. Elevations in inflammatory markers and severity scores predict worse outcomes, especially in high-risk subgroups. Early recognition and targeted interventions, including infection control and supportive measures, may attenuate disease severity and improve patient survival.

Dysregulated nicotinamide adenine dinucleotide metabolome in patients hospitalized with COVID-19.

Nicotinamide adenine dinucleotide (NAD+) depletion has been postulated as a contributor to the severity of COVID-19; however, no study has prospectively characterized NAD+ and its metabolites in relation to disease severity in patients with COVID-19. We measured NAD+ and its metabolites in 56 hospitalized patients with COVID-19 and in two control groups without COVID-19: (1) 31 age- and sex-matched adults with comorbidities, and (2) 30 adults without comorbidities. Blood NAD+ concentrations in COVID-19 group were only slightly lower than in the control groups (p < 0.05); however, plasma 1-methylnicotinamide concentrations were significantly higher in patients with COVID-19 (439.7 ng/mL, 95% CI: 234.0, 645.4 ng/mL) than in age- and sex-matched controls (44.5 ng/mL, 95% CI: 15.6, 73.4) and in healthy controls (18.1 ng/mL, 95% CI 15.4, 20.8; p < 0.001 for each comparison). Plasma nicotinamide concentrations were also higher in COVID-19 group and in controls with comorbidities than in healthy control group. Plasma concentrations of 2-methyl-2-pyridone-5-carboxamide (2-PY), but not NAD+, were significantly associated with increased risk of death (HR = 3.65; 95% CI 1.09, 12.2; p = 0.036) and escalation in level of care (HR = 2.90, 95% CI 1.01, 8.38, p = 0.049). RNAseq and RTqPCR analyses of PBMC mRNA found upregulation of multiple genes involved in NAD+ synthesis as well as degradation, and dysregulation of NAD+-dependent processes including immune response, DNA repair, metabolism, apoptosis/autophagy, redox reactions, and mitochondrial function. Blood NAD+ concentrations are modestly reduced in COVID-19; however, NAD+ turnover is substantially increased with upregulation of genes involved in both NAD+ biosynthesis and degradation, supporting the rationale for NAD+ augmentation to attenuate disease severity.

Myelin-reactive B cells exacerbate CD4+ T cell-driven CNS autoimmunity in an IL-23-dependent manner

B cells and T cells collaborate in multiple sclerosis (MS) pathogenesis. IgH[MOG] mice possess a B cell repertoire skewed to recognize myelin oligodendrocyte glycoprotein (MOG). Here, we show that upon immunization with the T cell-obligate autoantigen, MOG[35-55], IgH[MOG] mice develop rapid and exacerbated experimental autoimmune encephalomyelitis (EAE) relative to wildtype (WT) counterparts, characterized by aggregation of T and B cells in the IgH[MOG] meninges and by CD4+ T helper 17 (Th17) cells in the CNS. Production of the Th17 maintenance factor IL-23 is observed from IgH[MOG] CNS-infiltrating and meningeal B cells, and in vivo blockade of IL-23p19 attenuates disease severity in IgH[MOG] mice. In the CNS parenchyma and dura mater of IgH[MOG] mice, we observe an increased frequency of CD4+PD-1+CXCR5- T cells that share numerous characteristics with the recently described T peripheral helper (Tph) cell subset. Further, CNS-infiltrating B and Tph cells from IgH[MOG] mice show increased reactive oxygen species (ROS) production. Meningeal inflammation, Tph-like cell accumulation in the CNS and B/Tph cell production of ROS were all reduced upon p19 blockade. Altogether, MOG-specific B cells promote autoimmune inflammation of the CNS parenchyma and meninges in an IL-23-dependent manner.

POLR3A-related disorders: From spastic ataxia to generalised dystonia and long-term efficacy of deep brain stimulation.

While biallelic POLR3A loss-of-function variants are traditionally linked to hypomyelinating leukodystrophy, patients with a specific splice variant c.1909+22G>A manifest as adolescent-onset spastic ataxia without overt leukodystrophy. In this study, we reported eight new cases, POLR3A-related disorder with c.1909+22 variant. One of these patients showed expanded phenotypic spectrum of generalised dystonia and her sister remained asymptomatic except for hypodontia. Two patients with dystonic arm tremor responded to deep brain stimulation. In our systemic literature review, we found that POLR3A-related disorder with c.1909+22 variant has attenuated disease severity but frequency of dystonia and upper limb tremor did not differ among genotypes.

Complement Activation Is Associated With Disease Severity in Multiple Sclerosis.

Histopathologic studies have identified immunoglobulin (Ig) deposition and complement activation as contributors of CNS tissue damage in multiple sclerosis (MS). Intrathecal IgM synthesis is associated with higher MS disease activity and severity, and IgM is the strongest complement-activating immunoglobulin. In this study, we investigated whether complement components (CCs) and complement activation products (CAPs) are increased in persons with MS, especially in those with an intrathecal IgM synthesis, and whether they are associated with disease severity and progression. CC and CAP levels were quantified in plasma and CSF of 112 patients with clinically isolated syndrome (CIS), 127 patients with MS (90 relapsing-remitting, 14 primary progressive, and 23 secondary progressive), 31 inflammatory neurologic disease, and 44 symptomatic controls from the Basel CSF databank study. Patients with CIS/MS were followed in the Swiss MS cohort study (median 6.3 years). Levels of CC/CAP between diagnosis groups were compared; in CIS/MS, associations of CC/CAP levels with intrathecal Ig synthesis, baseline Expanded Disability Status Scale (EDSS) scores, MS Severity Score (MSSS), and neurofilament light chain (NfL) levels were investigated by linear regression, adjusted for age, sex, and albumin quotient. CSF (but not plasma) levels of C3a, C4a, Ba, and Bb were increased in patients with CIS/MS, being most pronounced in those with an additional intrathecal IgM production. In CIS, doubling of C3a and C4a in CSF was associated with 0.31 (CI 0.06-0.56; p = 0.016) and 0.32 (0.02-0.62; p = 0.041) increased EDSS scores at lumbar puncture. Similarly, doubling of C3a and Ba in CIS/MS was associated with 0.61 (0.19-1.03; p < 0.01) and 0.74 (0.18-1.31; p = 0.016) increased future MSSS. In CIS/MS, CSF levels of C3a, C4a, Ba, and Bb were associated with increased CSF NfL levels, e.g., doubling of C3a was associated with an increase of 58% (Est. 1.58; CI 1.37-1.81; p < 0.0001). CNS-compartmentalized activation of the classical and alternative pathways of complement is increased in CIS/MS and associated with the presence of an intrathecal IgM production. Increased complement activation within the CSF correlates with EDSS, future MSSS, and NfL levels, supporting the concept that complement activation contributes to MS pathology and disease progression. Complement inhibition should be explored as therapeutic target to attenuate disease severity and progression in MS.

NAD+ affects differentially expressed genes-MBOAT2-SLC25A21-SOX6 in experimental autoimmune encephalomyelitis model

Background Nicotinamide adenine dinucleotide (NAD+) plays a key role in neuroinflammation and neurodegeneration and provides anti-inflammatory and neuroprotective effects in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). Aim In this study, we aimed to investigate whether NAD+ affects differentially expressed genes (DEGs) in splenocytes of EAE mice to reveal candidate genes for the pathogenesis of MS. Methods The EAE model was used to perform an intervention on NAD+ to investigate its potential as a protective agent in inflammation and demyelination. Transcriptome analysis of nerve tissue was carried out to gain better insights into NAD+ function. Effects of NAD+ on DEGs in the splenocytes of EAE mice were investigated to determine its anti-inflammatory effect. Results NAD+ in EAE mice showed the clinical score was significantly improved (EAE 3.190 ± 0.473 vs. NAD+ 2.049 ± 0.715). DEGs (MBOAT2, SLC25A21, and SOX6) between the EAE and the EAE + NAD+ groups showed that SOX6 was significantly improved after NAD+ treatment compared with the EAE group, and other indicators were improved but did not reach statistical significance. NAD+ exhibited clinical scores in EAE mice, and key inflammation was ameliorated in EAE mice spleen after NAD+ intervention, while transcriptome analysis between EAE and EAE + NAD+ groups showed several DEGs in the underlying mechanism. Conclusion NAD+ on DEGs attenuates disease severity in EAE. Transcriptome analysis on nerve tissue reveals several protein targets in the underlying mechanisms. However, NAD+ does not significantly improve DEGs in the splenocytes of the EAE model.

A chlorogenic acid-conjugated nanomicelle attenuates disease severity in experimental arthritis.

Rheumatoid arthritis (RA) is a systemic immune disorder marked by synovitis, bone damage, and cartilage erosion, leading to increased socio-economic burdens and reduced quality of life. Despite its unknown cause, advancements in understanding its pathophysiology have facilitated novel therapeutic approaches. Current treatments, including disease-modifying anti-rheumatic drugs (DMARDs) and biologics, often result in low efficacy and unnecessary side effects. To address the limitations of these drugs, carrier-based drug delivery systems, such as nanomicelles, have emerged as a promising solution. In this study, nanomicelles were synthesised utilizing PLGA (poly(lactic-co-glycolic acid)) as a backbone; this backbone is conjugated with chlorogenic acid (CGA), which is known for suppressing inflammation, and incorporates methotrexate (MTX), a model drug that is established for RA treatment. The nanomicelles were extensively characterized in terms of size, charge, drug loading, and drug-release behaviour. The in vivo assessment of MTX-PLGA-b-CGA nanomicelles in a collagen-induced arthritis model demonstrated a remarkable reduction in joint swelling, cartilage erosion, and disease severity. Furthermore, histological findings confirmed cartilage integrity and reduced expression of key pro-inflammatory markers, including receptor activator of nuclear factor kappa beta ligand (RANKL) and tumor necrosis factor (TNF-α). The approach based on the MTX-PLGA-b-CGA nanomicelles presents a biocompatible and potentially effective therapeutic strategy for management of the severity and progression of RA, providing a hopeful alternative for RA treatment.

Cyclin D-CDK4 Disulfide Bond Attenuates Pulmonary Vascular Cell Proliferation.

Pulmonary hypertension (PH) is a chronic vascular disease characterized, among other abnormalities, by hyperproliferative smooth muscle cells and a perturbed cellular redox and metabolic balance. Oxidants induce cell cycle arrest to halt proliferation; however, little is known about the redox-regulated effector proteins that mediate these processes. Here, we report a novel kinase-inhibitory disulfide bond in cyclin D-CDK4 (cyclin-dependent kinase 4) and investigate its role in cell proliferation and PH. Oxidative modifications of cyclin D-CDK4 were detected in human pulmonary arterial smooth muscle cells and human pulmonary arterial endothelial cells. Site-directed mutagenesis, tandem mass-spectrometry, cell-based experiments, in vitro kinase activity assays, in silico structural modeling, and a novel redox-dead constitutive knock-in mouse were utilized to investigate the nature and definitively establish the importance of CDK4 cysteine modification in pulmonary vascular cell proliferation. Furthermore, the cyclin D-CDK4 oxidation was assessed in vivo in the pulmonary arteries and isolated human pulmonary arterial smooth muscle cells of patients with pulmonary arterial hypertension and in 3 preclinical models of PH. Cyclin D-CDK4 forms a reversible oxidant-induced heterodimeric disulfide dimer between C7/8 and C135, respectively, in cells in vitro and in pulmonary arteries in vivo to inhibit cyclin D-CDK4 kinase activity, decrease Rb (retinoblastoma) protein phosphorylation, and induce cell cycle arrest. Mutation of CDK4 C135 causes a kinase-impaired phenotype, which decreases cell proliferation rate and alleviates disease phenotype in an experimental mouse PH model, suggesting this cysteine is indispensable for cyclin D-CDK4 kinase activity. Pulmonary arteries and human pulmonary arterial smooth muscle cells from patients with pulmonary arterial hypertension display a decreased level of CDK4 disulfide, consistent with CDK4 being hyperactive in human pulmonary arterial hypertension. Furthermore, auranofin treatment, which induces the cyclin D-CDK4 disulfide, attenuates disease severity in experimental PH models by mitigating pulmonary vascular remodeling. A novel disulfide bond in cyclin D-CDK4 acts as a rapid switch to inhibit kinase activity and halt cell proliferation. This oxidative modification forms at a critical cysteine residue, which is unique to CDK4, offering the potential for the design of a selective covalent inhibitor predicted to be beneficial in PH.

Endurance Exercise Attenuates Established Progressive Experimental Autoimmune Encephalomyelitis and Is Associated with an Amelioration of Innate Immune Responses in NOD Mice

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease causing axonal degeneration and demyelination. Exercise in mice with active monophasic experimental autoimmune encephalomyelitis (EAE) attenuates disease severity associated with diverse impacts on T cell-mediated immunity. However, studies have so far focused on preventive approaches. In this study, we investigated the impact of endurance exercise on established EAE disease in a model of secondary progressive MS. When the exercise program on motorized running wheels was started at disease manifestation, the disease course was significantly ameliorated. This was associated with a significant decrease in B cell, dendritic cell, and neutrophil cell counts in the central nervous system (CNS). Furthermore, we observed an increased expression of major histocompatibility complex class II (MHC-II) as well as alterations in costimulatory molecule expression in CNS B cells and dendritic cells. In contrast, T cell responses were not altered in the CNS or periphery. Thus, exercise training is capable of attenuating the disease course even in established secondary progressive EAE, potentially via modulation of the innate immune compartment. Further studies are warranted to corroborate our findings and assess the potential of this lifestyle intervention as a complementary therapeutic strategy in secondary progressive MS patients.

Integrin α3 promotes TH17 cell polarization and extravasation during autoimmune neuroinflammation.

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) caused by CNS-infiltrating leukocytes, including TH17 cells that are critical mediators of disease pathogenesis. Although targeting leukocyte trafficking is effective in treating autoimmunity, there are currently no therapeutic interventions that specifically block encephalitogenic TH17 cell migration. Here, we report integrin α3 as a TH17 cell-selective determinant of pathogenicity in experimental autoimmune encephalomyelitis. CNS-infiltrating TH17 cells express high integrin α3, and its deletion in CD4+ T cells or Il17a fate-mapped cells attenuated disease severity. Mechanistically, integrin α3 enhanced the immunological synapse formation to promote the polarization and proliferation of TH17 cells. Moreover, the transmigration of TH17 cells into the CNS was dependent on integrin α3, and integrin α3 deficiency enhanced the retention of CD4+ T cells in the perivascular space of the blood-brain barrier. Integrin α3-dependent interactions continuously maintain TH17 cell identity and effector function. The requirement of integrin α3 in TH17 cell pathogenicity suggests integrin α3 as a therapeutic target for MS treatment.

High-Dose Influenza Vaccine Is Associated With Reduced Mortality Among Older Adults With Breakthrough Influenza Even When There Is Poor Vaccine-Strain Match.

High-dose (HD) influenza vaccine offers improved protection from influenza virus infection among older adults compared with standard-dose (SD) vaccine. Here, we explored whether HD vaccine attenuates disease severity among older adults with breakthrough influenza. This was a retrospective cohort study of US claims data for influenza seasons 2016-2017, 2017-2018, and 2018-2019, defined as 1 October through 30 April, among adults aged ≥65 years. After adjusting the different cohorts for the probability of vaccination conditional on patients' characteristics, we compared 30-day mortality rate post-influenza among older adults who experienced breakthrough infection after receipt of HD or SD influenza vaccines and among those not vaccinated (NV). We evaluated 44 456 influenza cases: 23 109 (52%) were unvaccinated, 15 037 (33.8%) received HD vaccine, and 6310 (14.2%) received SD vaccine. Significant reductions in mortality rates among breakthrough cases were observed across all 3 seasons for HD vs NV, ranging from 17% to 29% reductions. A significant mortality reduction of 25% was associated with SD vaccination vs NV in the 2016-2017 season when there was a good match between circulating influenza viruses and selected vaccine strains. When comparing HD vs SD cohorts, mortality reductions were higher among those who received HD in the last 2 seasons when mismatch between vaccine strains and circulating H3N2 viruses was documented, albeit not significant. HD vaccination was associated with lower post-influenza mortality among older adults with breakthrough influenza, even during seasons when antigenically drifted H3N2 circulated. Improved understanding of the impact of different vaccines on attenuating disease severity is warranted when assessing vaccine policy recommendations.

THE ORAL GLUTMATE CARBOXYPEPTIDASE II INHIBITOR (S)-IBD3540 ROBUSTLY ATTENUATES INFLAMMATION IN SPONTANEOUS IL10 COLITIS

Glutamate carboxypeptidase II (GCPII) is elevated in active inflamed biopsies of both Crohn’s disease and ulcerative colitis patients and is a promising therapeutic target for the treatment of IBD. We have previously presented the development and characterization of a first-in-class, gut-restricted, and orally active GCPII inhibitor, (S)-IBD3540, and have shown that oral (S)-IBD3540 attenuates disease severity in multiple murine colitis models, including acute dextran sulfate sodium (DSS)-induced colitis. Here, we extend our knowledge regarding (S)-IBD3540’s anti-inflammatory effects in spontaneously occurring colitis of interleukin 10 (IL10-/-) mice by performing longitudinal measurement of inflammatory biomarker fecal lipocalin 2 (LCN2) and terminal colon cytokine and chemokine measurements.

Lacticaseibacillus rhamnosus dfa1 Attenuate Cecal Ligation-Induced Systemic Inflammation through the Interference in Gut Dysbiosis, Leaky Gut, and Enterocytic Cell Energy.

Despite an uncommon condition, the clinical management of phlegmon appendicitis (retention of the intra-abdominal appendiceal abscess) is still controversial, and probiotics might be partly helpful. Then, the retained ligated cecal appendage (without gut obstruction) with or without oral Lacticaseibacillus rhamnosus dfa1 (started at 4 days prior to the surgery) was used as a representative model. At 5 days post-surgery, the cecal-ligated mice demonstrated weight loss, soft stool, gut barrier defect (leaky gut using FITC-dextran assay), fecal dysbiosis (increased Proteobacteria with reduced bacterial diversity), bacteremia, elevated serum cytokines, and spleen apoptosis without kidney and liver damage. Interestingly, the probiotics attenuated disease severity as indicated by stool consistency index, FITC-dextran assay, serum cytokines, spleen apoptosis, fecal microbiota analysis (reduced Proteobacteria), and mortality. Additionally, impacts of anti-inflammatory substances from culture media of the probiotics were demonstrated by attenuation of starvation injury in the Caco-2 enterocyte cell line as indicated by transepithelial electrical resistance (TEER), inflammatory markers (supernatant IL-8 with gene expression of TLR4 and NF-κB), cell energy status (extracellular flux analysis), and the reactive oxygen species (malondialdehyde). In conclusion, gut dysbiosis and leaky-gut-induced systemic inflammation might be helpful clinical parameters for patients with phlegmon appendicitis. Additionally, the leaky gut might be attenuated by some beneficial molecules from probiotics.

THE ORAL GLUTMATE CARBOXYPEPTIDASE II INHIBITOR (S)-IBD3540 ROBUSTLY ATTENUATES INFLAMMATION IN SPONTANEOUS IL10 COLITIS

Abstract BACKGROUND &amp; AIMS Glutamate carboxypeptidase II (GCPII) is elevated in active inflamed biopsies of both Crohn’s disease and ulcerative colitis patients and is a promising therapeutic target for the treatment of IBD. We have previously presented the development and characterization of a first-in-class, gut-restricted, and orally active GCPII inhibitor, (S)-IBD3540, and have shown that oral (S)-IBD3540 attenuates disease severity in multiple murine colitis models, including acute dextran sulfate sodium (DSS)-induced colitis. Here, we extend our knowledge regarding (S)-IBD3540’s anti-inflammatory effects in spontaneously occurring colitis of interleukin 10 (IL10-/-) mice by performing longitudinal measurement of inflammatory biomarker fecal lipocalin 2 (LCN2) and terminal colon cytokine and chemokine measurements. METHODS Female BALB/cAnNTac-Il10em7Tac mice (Taconic, Germantown, NY) were acquired at 4 weeks of age and monitored three times weekly for the onset of clinical signs, including alterations in stool consistency. Following onset of symptoms, groups were randomized and treatment was initiated with vehicle or 100 mg/kg eq. (S)-IBD3540 once daily by oral gavage. Prior to treatment, and biweekly thereafter, fecal LCN2 was quantified using a mouse Lipocalin-2/NGAL DuoSet ELISA (R&amp;D Systems). Upon study termination, proximal colon homogenates were prepared and analyzed by a mouse Cytokine/Chemokine 31-Plex Discovery Assay Array (Eve Technologies). RESULTS Impressively, despite initiating treatment in highly symptomatic mice 100 mg/kg oral (S)-IBD3540 was found to reverse abnormalities in stool consistency. Additionally, (S)-IBD3540 had potent anti-inflammatory effects. As expected, fecal LCN2 was observed to increase throughout the study period in vehicle treated mice, however, fecal LCN2 was significantly decreased in (S)-IBD3540 treated mice (p&amp;lt;0.05). Similarly, colon multiplex analysis identified significant reductions in multiple cytokines and chemokines implicated in IL10 colitis pathobiology, with notable reductions in cytokines TNFa, IL-12p40, and IL-17, and chemokines IP-10 and MIP-2. CONCLUSION (S)-IBD3540 is a novel, gut-restricted, GCPII inhibitor that has robust anti-inflammatory activity in IL10-/- colitis. Encouragingly, we have now found that in this model (S)-IBD3540 reduces pro-inflammatory cytokines/chemokines that are the targets of existing IBD medications. Studies to compare efficacy to one of these agents, anti-IL-12p40, are in progress.

Impact of Phospholipase C Gamma 2 Alzheimer's Disease Variants on Microglial Biology and Disease Pathogenesis

AbstractBackgroundAlzheimer’s disease (AD) and other neurodegenerative diseases are typified by a robust microglial‐mediated immune response. Phospholipase C gamma 2 (PLCG2), whose variants confer altered risk for AD, is a critical signaling element for various immune receptors and is a key regulatory hub gene for immune signaling. A functional hypermorphic P522R variant (rs72824905) of PLCG2 has been identified to be protective against AD (OR= 0.68, p=5.83‐10). Significantly, we identified a novel SNP (rs617749044) associated with elevated AD risk (OR=1.164; p=0.047) encoding the PLCG2 M28L variant.MethodTo investigate the impact of PLCG2 AD risk variants on microglial biology and disease pathogenesis, we have generated mice bearing either the M28L risk or the P522R protective PLCG2 variant, all crossed onto the 5XFAD amyloidogenic murine model of AD.ResultHere, we provide comprehensive analysis of PLCG2 action in mouse models of AD. We demonstrate that PLCG2 variants regulate protein‐protein interaction, alter microglial phenotypes in 5XFAD mice, regulate cytokine levels, drive distinct transcriptional phenotypes of microglia, and affect plaque pathology. Our data demonstrate that the M28L variant results in accelerated and exacerbated disease‐related pathology, and conversely, the P522R variant appeared to attenuate disease severity and progression.ConclusionTogether, our finding provides evidence that PLCG2 play an important role in AD pathophysiology, indicating PLCG2 as a potential new therapeutic target for AD.

MTORC1 links pathology in experimental models of Still’s disease and macrophage activation syndrome

Still’s disease is a severe inflammatory syndrome characterized by fever, skin rash and arthritis affecting children and adults. Patients with Still’s disease may also develop macrophage activation syndrome, a potentially fatal complication of immune dysregulation resulting in cytokine storm. Here we show that mTORC1 (mechanistic target of rapamycin complex 1) underpins the pathology of Still’s disease and macrophage activation syndrome. Single-cell RNA sequencing in a murine model of Still’s disease shows preferential activation of mTORC1 in monocytes; both mTOR inhibition and monocyte depletion attenuate disease severity. Transcriptomic data from patients with Still’s disease suggest decreased expression of the mTORC1 inhibitors TSC1/TSC2 and an mTORC1 gene signature that strongly correlates with disease activity and treatment response. Unrestricted activation of mTORC1 by Tsc2 deletion in mice is sufficient to trigger a Still’s disease-like syndrome, including both inflammatory arthritis and macrophage activation syndrome with hemophagocytosis, a cellular manifestation that is reproduced in human monocytes by CRISPR/Cas-mediated deletion of TSC2. Consistent with this observation, hemophagocytic histiocytes from patients with macrophage activation syndrome display prominent mTORC1 activity. Our study suggests a mechanistic link of mTORC1 to inflammation that connects the pathogenesis of Still’s disease and macrophage activation syndrome.

Targeting transmembrane-domain-less MOG expression to platelets prevents disease development in experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system with no cure yet. Here, we report genetic engineering of hematopoietic stem cells (HSCs) to express myelin oligodendrocyte glycoprotein (MOG), specifically in platelets, as a means of intervention to induce immune tolerance in experimental autoimmune encephalomyelitis (EAE), the mouse model of MS. The platelet-specific αIIb promoter was used to drive either a full-length or truncated MOG expression cassette. Platelet-MOG expression was introduced by lentivirus transduction of HSCs followed by transplantation. MOG protein was detected on the cell surface of platelets only in full-length MOG-transduced recipients, but MOG was detected in transmembrane-domain-less MOG1-157-transduced platelets intracellularly. We found that targeting MOG expression to platelets could prevent EAE development and attenuate disease severity, including the loss of bladder control in transduced recipients. Elimination of the transmembrane domains of MOG significantly enhanced the clinical efficacy in preventing the onset and development of the disease and induced CD4+Foxp3+ Treg cells in the EAE model. Together, our data demonstrated that targeting transmembrane domain-deleted MOG expression to platelets is an effective strategy to induce immune tolerance in EAE, which could be a promising approach for the treatment of patients with MS autoimmune disease.

Comparative study of clinical features and vaccination status in Omicron and non-Omicron infected patients during the third wave in Mumbai, India.

The Omicron variant-mediated COVID-19 wave is responsible for a global tsunami of cases. There is scarce data about the clinical and epidemiological characteristic analyses of the third wave. We present the data of COVID-19 patients from Mumbai region during the early third wave by taking S-gene target failure (SGTF) as a proxy for probable Omicron cases. We collected retrospective data of RT-PCR-confirmed (COVID-19) patients, and measured the proportion of possible Omicron cases by SGTF. We segregated and analyzed the clinical and lab data of patients with outcomes such as differing symptoms, vaccination coverage, previous infection, and travel history. We also performed a trend analysis of Mumbai's COVID-19 data before and during the third wave. All patients had mild clinical symptoms while few were asymptomatic. Myalgia was more significantly present in SGTF/Omicron cases compared to non-SGTF/Delta patients. Out of the total 101 COVID-positive individuals, 94 individuals (93%) had taken two doses of COVID vaccine. Among these 94 individuals, 9 (8.9%) had been previously infected with COVID 19 in the first or second waves. 77.7% of the previously infected were now infected with Omicron variant and only 22.3% by a non-Omicron variant. Rapid rise and fall during the third wave in Mumbai was due to Omicron cases gradually replacing Delta. The overall milder clinical spectrum in both Omicron and Delta cases imply that vaccines might not be effective against re-infection but can attenuate disease severity and mortality, as evident by high coverage of vaccination in the country.

Clozapine reduces chemokine-mediated migration of lymphocytes by targeting NF-κB and AKT phosphorylation

Multiple sclerosis is a disease characterised by demyelination of axons in the central nervous system. The atypical antipsychotic drug clozapine has been shown to attenuate disease severity in experimental autoimmune encephalomyelitis (EAE), a mouse model that is useful for the study of multiple sclerosis. However, the mechanism of action by which clozapine reduces disease in EAE is poorly understood. To better understand how clozapine exerts its protective effects, we investigated the underlying signalling pathways by which clozapine may reduce immune cell migration by evaluating chemokine and dopamine receptor-associated signalling pathways. We found that clozapine inhibits migration of immune cells by reducing chemokine production in microglia cells by targeting NF-κB phosphorylation and promoting an anti-inflammatory milieu. Furthermore, clozapine directly targets immune cell migration by changing Ca2+ levels within immune cells and reduces the phosphorylation of signalling protein AKT. Linking these pathways to the antagonising effect of clozapine on dopamine and serotonin receptors, we provide insight into how clozapine alters immune cells migration by directly targeting the underlying migration-associated pathways.

Early report on the severity of COVID-19 in hematologic patients infected with the SARS-CoV2 omicron variant.

IntroductionPatients with hematologic disease are at high risk of morbidity and mortality from COVID‐19 due to disease‐inherent and therapy‐related immunodeficiency. Whether infection with the SARS‐CoV2 omicron variant leads to attenuated disease severity in these patients is currently unknown.MethodsWe assessed clinical and laboratory parameters in 61 patients with underlying hematologic conditions with a SARS‐CoV2 omicron variant infection confirmed by nucleic acid amplification testing.ResultsFifty patients reported symptoms of COVID‐19, most commonly fatigue (37 patients, 60.66%) and cough (32 patients, 52.46%). 39.34% of patients reported fever. Dyspnea was reported by 10 patients and 7 patients (11.48%) required oxygen therapy. Anosmia and ageusia were relatively rare, occurring in less than 10% of patients. Severity of SARS‐CoV2 infection could be assessed in 60 patients. Five cases of critical illness leading to ICU admission occurred during the observation period. Overall mortality was 9.84% in this patient cohort, with heterogeneous causes of death. The majority of omicron‐infected hematologic patients experienced mild symptoms or remained asymptomatic.DiscussionIn this study, symptoms of COVID‐19 tended to be milder than described for previous SARS‐CoV2 variants. However, the extent to which attenuated severity of omicron‐variant SARS‐CoV2 infection is caused by altered viral pathogenicity or pre‐existing host immunity cannot be inferred from our data and should be investigated in larger prospective studies.