Interleukin-6 Receptor Blockade Research Articles

The NLRP3 inflammasome is essential for IL-18 production in a murine model of macrophage activation syndrome.

Hyperinflammatory disease is associated with an aberrant immune response resulting in cytokine storm. One such instance of hyperinflammatory disease is known as macrophage activation syndrome (MAS). The pathology of MAS can be characterised by significantly elevated serum levels of interleukin-18 (IL-18) and interferon gamma (IFNγ). Given the role for IL-18 in MAS, we sought to establish the role of inflammasomes in the disease process. Using a murine model of CpG-oligonucleotide-induced MAS, we discovered that the expression of the NLRP3 inflammasome was increased and correlated with IL-18 production. Inhibition of the NLRP3 inflammasome or the downstream caspase-1 prevented MAS-mediated upregulation of IL-18 in the plasma but, interestingly, did not alleviate key features of hyperinflammatory disease including hyperferritinaemia and splenomegaly. Furthermore blockade of IL-1 receptor with its antagonist IL-1Ra did not prevent the development of CpG-induced MAS, despite being clinically effective in the treatment of MAS. These data demonstrate that, during the development of MAS, the NLRP3 inflammasome was essential for the elevation in plasma IL-18 - a key cytokine in clinical cases of MAS - but was not a driving factor in the pathogenesis of CpG-induced MAS.

Monoclonal Antibody Treatment for Relapse Prevention in Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system that can lead to devastating neurological disabilities such as blindness and impaired mobility. Given that NMOSD can cause severe neurological deteriorations even with a single episode, exploring effective relapse prevention strategies in NMOSD is imperative. Recently, various biological monoclonal antibody therapies targeting diverse mechanisms have shown efficacy in preventing relapses in NMOSD, as evidenced by clinical trials. These monoclonal antibody therapies include complement inhibition (eculizumab and ravulizumab), B-cell depletion (rituximab and inebilizumab), and interleukin-6 receptor blockade (tocilizumab and satralizumab) mechanisms. Some of these therapies are now reimbursable, and this review summarizes their mechanisms, administration methods, reimbursement status in Korea, efficacy, and safety profiles in clinical practice.

Monoclonal Antibody Treatment for Relapse Prevention in Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system that can lead to devastating neurological disabilities such as blindness and impaired mobility. Given that NMOSD can cause severe neurological deteriorations even with a single episode, exploring effective relapse prevention strategies in NMOSD is imperative. Recently, various biological monoclonal antibody therapies targeting diverse mechanisms have shown efficacy in preventing relapses in NMOSD, as evidenced by clinical trials. These monoclonal antibody therapies include complement inhibition (eculizumab and ravulizumab), B-cell depletion (rituximab and inebilizumab), and interleukin-6 receptor blockade (tocilizumab and satralizumab) mechanisms. Some of these therapies are now reimbursable, and this review summarizes their mechanisms, administration methods, reimbursement status in Korea, efficacy, and safety profiles in clinical practice.

Interleukin-6 receptor blockade with tocilizumab to reduce immune-related toxicity with ipilimumab and nivolumab in metastatic melanoma.

9538 Background: Interleukin-6(IL-6) blockade has reversed steroid-refractory immune-related toxicity in patients receiving immune checkpoint blockade (ICB). IL-6 and its downstream acute phase reactants are also associated with short survival and therapeutic resistance in patients receiving single agent or combination ICB. We undertook a phase II trial of IPI, NIVO and the IL-6 receptor blocking antibody tocilizumab (TOCI) in unresectable melanoma. Methods: In a phase II, Simon-design two-stage trial, 70 patients with untreated metastatic melanoma received IPI at 1 mg/kg and NIVO at 3 mg/kg for 4 induction doses to week 12, and TOCI at 4 mg/kg every 6 weeks up to week 24. Maintenance NIVO was administered at 240 mg intravenously (IV) from weeks 12 to 24, then at a dose of 480 mg IV every 4 weeks for up to 2 years of treatment. To proceed past the first stage of 18 patients, 12/18 RECIST responses or more and/or a grade 3-5 treatment related immune-related adverse event (irAE) rate of ≤5/18 were required. Those criteria were both fulfilled, and in the second stage 49 patients were treated, with 3 additional patients accrued. Serum and peripheral blood samples were collected for biomarker assays at baseline and week 7. Results: There were 40/70 RECIST responders with a 57% best overall response rate (BORR), (exact 95% confidence interval (CI) of 44-68%) of partial response (PR) or complete response (CR); 6 patients had stable disease (SD), 24 with progression, at a median of 2.4 years of follow-up. A total of 46 patients had clinical benefit (CR+PR+SD) = 65% (exact 95% CI 37-81%). Median progression-free survival was 13 months. The expected BORR was 47% in the randomized Checkmate-511 trial at the same doses of IPI/NIVO. There have been 16 cases of grades 3-4 irAE including 3 episodes of colitis for a total of 16/71 patients eligible for toxicity = 22% (exact 95% CI: 12-31%), all grade 3/4; the expected rate of grades 3-5 TRAEs was 34% per Checkmate-511. The rate of irAE leading to discontinuation was 14%; it was 25% for CheckMate 511. Twenty-one deaths (30%) occurred, all due to progression. All grade 3-4 irAES were reversible and no grade 5 toxicity was seen. Osteopontin+IL6+CD45RAnegclassical monocytes were associated with response, and higher levels of naive CD8 T cells were associated with progression. CD16+CD56+CD57+ mature natural killer cells were significantly lower in patients with grade 3-4 immune-related toxicity. Conclusions: Prophylactic TOCI resulted in a low rate of grade 3-4 irAEs by week 24 in patients with stage IV melanoma receiving induction IPI 1 mg/kg and NIVO 3 mg/kg while maintaining a favorable overall response rate and survival. Novel biomarkers of response and toxicity including NK cells and monocytes as well as naïve and effector memory CD8 T cells were defined by high-resolution flow cytometry. Additional correlative data will be presented. Clinical trial information: NCT03999749 .

Phase II trial of weekly or bi-weekly tocilizumab with ipilimumab and nivolumab in advanced melanoma: Clinical outcomes and biomarker analysis.

9553 Background: Combination immune-checkpoint inhibitors (ICIs) improved outcomes in a plethora of cancer subtypes. However, up to 60% of patients (pts) receiving ipilimumab (ipi) plus nivolumab (nivo) experience grade 3/4 (G 3/4) immune-related adverse events (irAEs), often leading to treatment discontinuation. We evaluated two therapeutic strategies targeting interleukin-6 receptor (IL-6R) to reduce irAEs while enhancing ICls efficacy. Methods: Phase Il trial (NCT04940299) investigating safety/efficacy of frontline tocilizumab (toci; IL-6R inhibitor) combined with ipi 3mg/kg + nivo 1mg/kg Q3 weeks (wks) for 12 wks in advanced melanoma. Initially, toci was given as 162 mg subcutaneously (SQ) bi-weekly for 6 doses (regular dosing regimen; RD). Then, we escalated to a dose dense (DD) regimen (162 mg SQ weekly for 6 wks then bi-weekly for 6 wks; 9 doses total). Primary objective was rate of G 3/4 irAEs. Secondary objectives were objective response rates (ORR) and disease control rate (DCR) per RECIST 1.1. Exploratory objectives involved immune analysis (gene expression, CyTOF, cytokine analysis) on longitudinal blood and tissue samples to identify drivers of auto- vs antitumor immunity. Results: As of Feb 2024, 35 pts were enrolled (25 pts to RD regimen; 10 pts to DD regimen). In RD group, median follow-up is 18 months (6 - 25 months). By 12 wks, 44% of pts developed G 3/4 irAEs including colitis (20%), hepatitis (16%), pancreatitis (12%), type I diabetes and serum sickness (4% each) and 20% of pts required hospitalization due to irAEs. Median time to G 3/4 irAEs onset was 7.4 wks. 16% of pts discontinued ICIs due to irAEs. ORR was 56% at 12 wks including 40% in pts with high LDH and DCR was 80%. Gene expression analysis showed a trend towards higher expression of IL-17 pathway genes in pts who developed G 3/4 irAEs, suggesting IL-6/Th17 pathway was not sufficiently inhibited. Thus, we enrolled 10 pts into the DD regimen aiming to achieve better inhibition of the IL-6/Th17 pathway. In DD group, median follow-up is 7 months (3 - 13 months). By 12 wks, 40% of pts developed G 3/4 irAEs, including colitis (10%), hepatitis (20%), and uveitis (10%) and 30% of pts required hospitalization due to irAEs. Median time to G 3/4 irAEs onset was 4.9 wks. 30% of pts discontinued ICIs due to irAEs. ORR was 70% at 12 wks including 75% in pts with high LDH and DCR was 80%. Conclusions: To our knowledge, this is the first study to investigate toci in combination with high dose ipi3/nivo1. Although our cohort is small, preliminary data suggests IL-6R blockade using the DD regimen could decrease the rate of G 3/4 irAEs while maintaining antitumor responses of ipi3/nivo1. A randomized phase ll trial investigating this strategy is underway. Ongoing immune analysis comparing treatment regimens aims to identify distinct pathways involved in auto- vs antitumor immunity and IL-6/Th17 independent pathways of toxicity. Clinical trial information: NCT04940299 .

Absence of IL-6 Receptor Blockade Effect on the Outcomes of Transplant Glomerulopathy in the Absence of Anti-HLA Donor-specific Antibodies.

Transplant glomerulopathy (TG) is the hallmark of chronic antibody-mediated rejection but often occurs without anti-HLA donor-specific antibodies (DSAs) in the assumption that other DSAs may be the effectors of the tissue injury. Recently, we reported a positive effect of interleukin-6 (IL-6) receptor blocker tocilizumab (TCZ) in TG/DSA+. In the present study, we investigate the effect of TCZ in a cohort of TG cases without detectable anti-HLA DSAs. Single-center retrospective analysis of TG cases without anti-HLA DSAs (TG/DSA) treated with TCZ for chronic antibody-mediated rejection as first-line therapy evaluated through clinical, protocol biopsies, and gene expression analyses was included. Differently from TG/DSA+, TG/DSA- showed a progressive reduction in the estimated glomerular filtration rate at 12 mo and after that with no significant modification in microvascular inflammation or C4d+. No upregulation in tight junction protein-1, aldo-keto reductase family 1 member C3, and calcium/calmodulin-dependent serine protein kinase, documented in TG/DSA+, was noted in post-TCZ biopsies. The reduction of microvascular inflammation was associated with natural killer-cell reduction in TG/DSA+, whereas TG/DSA- tends to maintain or increase periglomerular/interstitial infiltration. In the absence of anti-HLA DSAs, TG behavior seems not to be modified by IL-6 receptor blockade. These results are at variance with observational studies and previous trials with IL-6 inhibitors in TG associated with anti-HLA DSAs. These data may fuel the hypothesis of different mechanisms underlying TGs (including the potentially different roles of natural killer cells) and suggest carefully selecting patients with TG for clinical trials or off-label treatment based on their antidonor serologic status.

Effect of IL-6R blockade on plasma lipids and clinical outcomes among hospitalized patients with COVID-19 infection

Plasma lipid levels are modulated by systemic infection and inflammation; it is unknown whether these changes reflect inflammatory responses or caused directly by pathogen presence. We explored the hypothesis that anti-inflammatory intervention via interleukin 6 receptor (IL-6R) blockade would influence plasma lipid levels during severe infection and evaluated the association of plasma lipid changes with clinical outcomes. Sarilumab (monoclonal antibody blocking IL-6R) efficacy was previously assessed in patients with coronavirus disease 2019 (COVID-19) (NCT04315298). This analysis determined whether strong inflammatory reduction by sarilumab in patients with COVID-19 pneumonia of increasing severity (severe, critical, multisystem organ dysfunction) affected plasma lipid changes between day 1 and day 7 of study therapy. Baseline lipid levels reflected the presence of acute systemic infection, characterized by very low HDL-C, low LDL-C, and moderately elevated triglycerides (TGs). Disease severity was associated with progressively more abnormal lipid levels. At day 7, median lipid levels increased more in the sarilumab versus placebo group (HDL-C +10.3%, LDL-C +54.7%, TG +32% vs. HDL-C +1.7%, LDL-C +15.4%, TG +8.8%, respectively). No significant association between lipid changes and clinical outcomes was observed. In conclusion, severe-to-critical COVID-19 pneumonia causes profound HDL-C depression that is only modestly responsive to strong anti-IL-6R inflammatory intervention. Conversely, LDL-C depression is strongly responsive to IL-6R blockade, with LDL-C levels likely returning to the predisease set point. These results advance our understanding of the complex relationship between serum lipids and infection/inflammation and suggest that HDL-C depression during acute contagious disease is driven by infection and not IL-6–mediated inflammation.

IL-6 receptor antibody treatment improves muscle weakness in experimental autoimmune myasthenia gravis mouse model.

Myasthenia gravis (MG) is a chronic autoimmune disease characterized by muscle weakness and fatigue. It is caused by pathological autoantibodies against components expressed at neuromuscular junctions, such as acetylcholine receptor (AChR). Interleukin-6 (IL-6) has been suggested to play a role in the pathogenesis of MG, and IL-6 receptor (IL-6R) antibody treatment may provide a novel therapeutic option. In this study, we investigated the effects of IL-6R antibody treatment in an experimental autoimmune MG (EAMG) mouse model. We demonstrated that IL-6R antibody treatment improved muscle weakness, reduced IgG deposition at neuromuscular junctions, and the levels of AChR autoantibodies in serum. In addition, follicular helper T cells and Th17, plasma cells in lymph nodes were lower in IL-6R antibody treated mice. Our findings suggest that IL-6R blockade may be a novel and effective therapeutic strategy for the treatment of MG.

(91) - IL-6 Receptor Blockade Induces Tolerance of Heart Allografts in NHPs in a Simultaneous but Not Delayed Mixed-Chimerism Protocol

(91) - IL-6 Receptor Blockade Induces Tolerance of Heart Allografts in NHPs in a Simultaneous but Not Delayed Mixed-Chimerism Protocol

Effects of interleukin-6 signal inhibition on Treg subpopulations and association of Tregs with clinical outcomes in rheumatoid arthritis.

Anti-IL-6 receptor antibodies are clinically efficacious in the management of rheumatoid arthritis (RA) with an associated increase in regulatory T cells (Tregs); however, the role of functional Treg subsets has yet to be clarified. This study aimed to evaluate how functional Treg subsets are altered by IL-6 receptor blockade and to analyze the relationship between these Treg subsets and the clinical outcome of RA. We collected frozen peripheral blood mononuclear cells (PBMCs) from 40 patients with RA who started tocilizumab (TCZ) with or without MTX and 11 healthy controls (HCs). We fractionated Tregs with flow cytometry based on markers of phenotype and function and measured the proportions of detailed Treg subsets sequentially from baseline to week 52. The proportions of resting Tregs (rTregs) and rTregs+activated Tregs (aTregs) were significantly lower in RA patients at baseline than in HCs. The proportions of all those CD127low Tregs, rTregs, aTregs, and rTregs+aTregs were significantly increased with TCZ treatment. In patients treated with TCZ without MTX, rTreg were increased. Patients with an increase in the proportion of rTregs at week 12 had significantly less arthritis flares during the observation period. Blocking IL-6 receptor with TCZ increased the proportion of rTregs, a functional Treg subpopulation. Patients with an early increase in rTregs showed a favorable treatment course, and this increase in rTregs may reflect molecular remission induced by IL-6 signal inhibition.

Fungal microbiota sustains lasting immune activation of neutrophils and their progenitors in severe COVID-19.

Gastrointestinal fungal dysbiosis is a hallmark of several diseases marked by systemic immune activation. Whether persistent pathobiont colonization during immune alterations and impaired gut barrier function has a durable impact on host immunity is unknown. We found that elevated levels of Candida albicans immunoglobulin G (IgG) antibodies marked patients with severe COVID-19 (sCOVID-19) who had intestinal Candida overgrowth, mycobiota dysbiosis and systemic neutrophilia. Analysis of hematopoietic stem cell progenitors in sCOVID-19 revealed transcriptional changes in antifungal immunity pathways and reprogramming of granulocyte myeloid progenitors (GMPs) for up to a year. Mice colonized with C. albicans patient isolates experienced increased lung neutrophilia and pulmonary NETosis during severe acute respiratory syndrome coronavirus-2 infection, which were partially resolved with antifungal treatment or by interleukin-6 receptor blockade. sCOVID-19 patients treated with tocilizumab experienced sustained reductions in C. albicans IgG antibodies titers and GMP transcriptional changes. These findings suggest that gut fungal pathobionts may contribute to immune activation during inflammatory diseases, offering potential mycobiota-immune therapeutic strategies for sCOVID-19 with prolonged symptoms.

Long-term Effects of IL-6 Receptor Blockade Therapy on Regulatory Lymphocytes and Neutrophils in Neuromyelitis Optica Spectrum Disorder.

Neuromyelitis optica spectrum disorder (NMOSD) is a disabling autoimmune neurologic disease. Anti-IL-6 receptor (IL-6R) therapy prevents relapses in patients with anti-aquaporin 4 (AQP4)-IgG-positive NMOSD; however, it remains unclear how cellular immune components are altered by anti-IL-6R therapy. In this study, we examined the long-term effects of the anti-IL-6R monoclonal antibody tocilizumab (TCZ) on immune cell profiles in patients with NMOSD. Monthly IV injections of TCZ (8 mg/kg) were administered as an add-on therapy to 19 anti-AQP4-IgG-positive patients, who had been refractory to corticosteroids and immunosuppressive drugs. Peripheral blood was collected before infusion of TCZ for flow cytometry analysis of lymphocyte subsets. Seven patients provided whole blood samples for gene expression profiles. Patients with NMOSD had reduced numbers of lymphocyte subsets with regulatory functions, including transitional B cells, CD56high NK cells, and CD45RA-FoxP3high regulatory T cells. However, after initiating TCZ therapy, the numbers increased to normal levels within 1 year. Gene expression analysis revealed that neutrophil granule-related genes, predominated by those related to azurophil granules, were significantly upregulated in patients with NMOSD. Such alterations suggestive of accelerated myeloid turnover were not observed 1 year after TCZ therapy, and the effects of TCZ on some neutrophil genes were observed as early as 5 days after starting TCZ. In vitro analysis demonstrated that naïve T-cell division was impaired in the enrolled patients, which was fully recovered after 18 months of therapy. In patients with active NMOSD not treated with molecular targeting drugs, we observed reduction or deficiency in lymphocytes with regulatory potentials and activation of neutrophils. However, introduction of anti-IL-6R therapy accompanied by tapering concomitant drugs corrected such abnormalities, which might contribute to persistent relapse prevention. The recovery in the naïve T-cell division after starting TCZ may underlie the relatively low risk of infection in patients under anti-IL-6R therapy. University Hospital Medical Information Network Clinical Trials Registry: UMIN000005889 (July 8, 2011) and UMIN000007866 (May 1, 2012) (umin.ac.jp/ctr/index.htm). The first participant was enrolled on November 2, 2011.

Therapeutic potential of single-nucleotide polymorphism-mediated interleukin-6 receptor blockade in cancer treatment: A Mendelian randomization study

BackgroundInterleukin-6 (IL-6) is a crucial member of the cytokine network and plays a pivotal role in the pathogenesis of various diseases, including cancer. IL-6 receptor (IL-6R) blockade is widely employed as a therapeutic strategy; however, its efficacy in anticancer therapy remains ambiguous. MethodsAn inverse variance-weighted Mendelian randomization (MR) analysis was conducted to assess the causal effects exerted by IL-6R blockade in remediating cancer. Drug-targeted single-nucleotide polymorphisms (SNPs) were introduced within 300 kb of the IL-6R gene. An instrumental variable comprising 26 SNPs represented IL-6 signaling downregulation and C-reactive protein level reduction. Datasets pertaining to the 33 types of cancer investigated in this study were acquired from the FinnGen genome-wide association study. ResultsThe selected instrumental variable lowered fibrinogen levels, confirming its ability to mimic IL-6R blockade. IL-6R blockade exhibited therapeutic effects on five different cancer types documented in the FinnGen database (N = 334,364, including 76,781 cancer patients): bladder (odds ratios (OR) = 0.563), laryngeal (OR = 0.293), eye (OR = 0.098), gallbladder (OR = 0.059), and myeloid leukemia (OR = 0.442); however, it simultaneously elevated the risk of developing basal cell carcinoma (OR = 1.312) and melanoma (OR = 1.311). Sensitivity analyses did not alter the primary results. ConclusionTherefore, this study aimed to evaluate the potential and efficacy of SNP-based IL-6R blockade in treating cancer.

Feasibility of Interleukin-6 Receptor Blockade in Cardiac Antibody-mediated Rejection.

Antibody-mediated rejection (AMR) remains a significant cause of heart transplant mortality with few effective therapies. This study aimed to describe initial experience of using interleukin-6 receptor blockade with tocilizumab in the treatment of acute cardiac AMR at Barnes-Jewish Hospital/Washington University Transplant Center from July 2017 to May 2021 (n = 7). Clinical, echocardiographic, and serum alloantibody data were analyzed before and after treatment. All participants demonstrated marked improvement in functional status. Echocardiographic data following 4-6 mo of tocilizumab revealed significant improvements in biventricular systolic function for all participants. Consistent reductions in donor-specific HLA or angiotensin type I receptor antibodies were not observed, suggesting that tocilizumab may act downstream of antibody production. No patient experienced drug-related complications that necessitated discontinuation of therapy. These findings provide initial insights into the safety and efficacy of interleukin-6 receptor blockade in the treatment of cardiac AMR and support the design of larger prospective studies.

Transcriptomic and proteomic assessment of tocilizumab response in a randomized controlled trial of patients hospitalized with COVID-19

High interleukin (IL)-6 levels are associated with greater COVID-19 severity. IL-6 receptor blockade by tocilizumab (anti-IL6R; Actemra) is used globally for the treatment of severe COVID-19, yet a molecular understanding of the therapeutic benefit remains unclear. We characterized the immune profile and identified cellular and molecular pathways modified by tocilizumab in peripheral blood samples from patients enrolled in the COVACTA study, a phase 3, randomized, double-blind, placebo-controlled trial of the efficacy and safety of tocilizumab in hospitalized patients with severe COVID-19. We identified markers of inflammation, lymphopenia, myeloid dysregulation, and organ injury that predict disease severity and clinical outcomes. Proteomic analysis confirmed a pharmacodynamic effect for tocilizumab and identified novel pharmacodynamic biomarkers. Transcriptomic analysis revealed that tocilizumab treatment leads to faster resolution of lymphopenia and myeloid dysregulation associated with severe COVID-19, indicating greater anti-inflammatory activity relative to placebo and potentially leading to faster recovery in patients hospitalized with COVID-19.

Interleukin-6 receptor blockade improves bone healing following ischemic osteonecrosis in adolescent mice

ObjectiveJuvenile ischemic osteonecrosis (JIO) of the femoral head is one of the most serious hip disorders causing a permanent deformity of the femoral head in childhood. We recently reported that interleukin 6 (IL-6) is significantly increased in the hip synovial fluid of patients with JIO and that articular chondrocytes are primary source of IL-6. Adolescent JIO is particularly challenging to treat and has poor outcome. This study determined if IL-6 receptor blockade prevents bone loss and improves the bone healing in adolescent JIO. MethodAdolescent mice (12-week-old) surgically induced with JIO were treated with either saline or MR16-1, an IL-6 receptor blocker. ResultsMicro-CT assessment showed significantly increased bone volume (p ​< ​0.001, Cohen's d ​= ​2.0) and trabecular bone thickness (p ​< ​0.001, d ​= ​2.3) after the MR16-1 treatment. Histomorphometric assessment showed significantly increased osteoblast number (p ​< ​0.01, d ​= ​2.3), bone formation rate (p ​< ​0.01, d ​= ​4.3), and mineral apposition rate (p ​< ​0.01, d ​= ​4.1) after the MR16-1 treatment. The number of osteoclasts was unchanged. Histologic assessment showed significantly increased revascularization (p ​< ​0.01) and restoration of the necrotic marrow with new hematopoietic bone marrow (p ​< ​0.01). Vascular endothelial growth factor (VEGF) expression was increased in the revascularized area and the articular cartilage, and in the cultured chondrocytes treated with IL-6 receptor inhibitor. ConclusionIL-6 blockade in adolescent mice with JIO enhanced bone formation and revascularization. The findings suggest IL-6 receptor blocker as a potential medical therapy for adolescent JIO.

Interleukin 1β triggers synaptic and memory deficits in Herpes simplex virus type-1-infected mice by downregulating the expression of synaptic plasticity-related genes via the epigenetic MeCP2/HDAC4 complex

Extensive research provides evidence that neuroinflammation underlies numerous brain disorders. However, the molecular mechanisms by which inflammatory mediators determine synaptic and cognitive dysfunction occurring in neurodegenerative diseases (e.g., Alzheimer’s disease) are far from being fully understood. Here we investigated the role of interleukin 1β (IL-1β), and the molecular cascade downstream the activation of its receptor, to the synaptic dysfunction occurring in the mouse model of multiple Herpes simplex virus type-1 (HSV-1) reactivations within the brain. These mice are characterized by neuroinflammation and memory deficits associated with a progressive accumulation of neurodegenerative hallmarks (e.g., amyloid-β protein and tau hyperphosphorylation). Here we show that mice undergone two HSV-1 reactivations in the brain exhibited increased levels of IL-1β along with significant alterations of: (1) cognitive performances; (2) hippocampal long-term potentiation; (3) expression synaptic-related genes and pre- and post-synaptic proteins; (4) dendritic spine density and morphology. These effects correlated with activation of the epigenetic repressor MeCP2 that, in association with HDAC4, affected the expression of synaptic plasticity-related genes. Specifically, in response to HSV-1 infection, HDAC4 accumulated in the nucleus and promoted MeCP2 SUMOylation that is a post-translational modification critically affecting the repressive activity of MeCP2. The blockade of IL-1 receptors by the specific antagonist Anakinra prevented the MeCP2 increase and the consequent downregulation of gene expression along with rescuing structural and functional indices of neurodegeneration. Collectively, our findings provide novel mechanistic evidence on the role played by HSV-1-activated IL-1β signaling pathways in synaptic deficits leading to cognitive impairment.

Serum rescues surgical manipulation induced intestinal barrier permeability greater than interleukin 1 receptor antagonist conditioned serum in large animal model

Surgical manipulation induced intestinal barrier permeability has been previously demonstrated in rodent models and may prove crucial in the development of postoperative complications such as postoperative ileus and sepsis. However, the observation of this phenomena in a large animal model, and further understanding of mechanisms as well as potential therapeutic approaches has yet to be fully explored. The enteric glial cell population may prove to be a critical participant as they sense the intestinal environment and communicate rapidly with surrounding cell populations. Blockade of glial IL-1 receptor has proven successful in preventing postoperative ileus, a possible sequela of barrier permeability, in a rodent model. Therefore, we hypothesized that a large animal model would demonstrate surgical manipulation-induced intestinal barrier permeability, which could be prevented by luminal injection of interleukin 1 receptor antagonist conditioned serum (IRAP). Ischemia was first induced in the distal jejunum of 6–8-week-old pigs to mimic the disease process that would require intestinal surgery. Jejunum proximal and distal to the ischemic loops was then manipulated by “milking” the intestinal contents and applying friction to the serosa with sterile gauze with and without the injection of 1ml of nonconditioned porcine serum or IRAP into the proximal or distal loop. Forty-five minutes after manipulation, the tissues were collected for immunofluorescence histology and mounted on Ussing chambers to measure transepithelial electrical resistance (TEER) which directly corresponds to mucosal barrier resistance. TEER values for the manipulated proximal intestine were significantly more permeable than control tissue (p&lt;0.0001). In addition, preliminary fluorescent quantification has indicated an increase in glial marker, glial fibrillary acidic protein, in the manipulated tissue (p =0.0499). TEER values for manipulated distal tissue trended towards increased permeability compared to control tissue (p=0.1995). Addition of IRAP significantly increased the resistance of the proximal loop compared to manipulation alone (p=0.0003). Interestingly, addition of control porcine serum significantly increased the resistance of both the proximal and distal loops compared to manipulation alone, and to a greater extent than IRAP (p= &lt;0.0001 and 0.0008 respectively).While the effects of IRAP on interleukin 1 signaling may play a role in prevention of surgical manipulation induced intestinal barrier permeability, it appears than non-conditioned serum may offer therapeutic benefits. Ongoing studies will focus on determining the mechanism of this therapeutic effect on the intestinal epithelia and glia population. NIH K01 OD 028207, NIH-NICHD R01 HD095876 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Macrophage secretory IL-1β promotes docetaxel resistance in head and neck squamous carcinoma via SOD2/CAT-ICAM1 signaling.

Docetaxel (DTX) combined with cisplatin and 5-fluorouracil has been used as induction chemotherapy for head and neck squamous cell carcinoma (HNSCC). However, the development of acquired resistance remains a major obstacle to treatment response. Tumor-associated macrophages are associated with chemotherapeutic resistance. In the present study, increased infiltration of macrophages into the tumor microenvironment (TME) was significantly associated with shorter overall survival and increased resistance to chemotherapeutic drugs, particularly DTX, in patients with HNSCC. Macrophage coculture induced expression of intercellular adhesion molecule 1 (ICAM1), which promotes stemness and the formation of polyploid giant cancer cells, thereby reducing the efficacy of DTX. Both genetic silencing and pharmacological inhibition of ICAM1 sensitized HNSCC to DTX. Macrophage secretion of IL-1β was found to induce tumor expression of ICAM1. IL-1β neutralization and IL-1 receptor blockade reversed DTX resistance induced by macrophage coculture. IL-1β activated superoxide dismutase 2 and inhibited catalase, thereby modulating intracellular levels of ROS and inducing ICAM1 expression. Arsenic trioxide (ATO) reduced macrophage infiltration into the TME and impaired IL-1β secretion by macrophages. The combinatorial use of ATO enhanced the in vivo efficacy of DTX in a mouse model, which may provide a revolutionary approach to overcoming acquired therapeutic resistance in HNSCC.

Addition of interleukin-6 receptor blockade to carfilzomib-based desensitization in a highly sensitized nonhuman primate model

Sensitized patients, those who had prior exposure to foreign human leukocyte antigens, are transplanted at lower rates due to challenges in finding suitable organs. Desensitization strategies have permitted highly sensitized patients to undergo kidney transplantation, albeit with higher rates of rejection. This study assesses targeting plasma cell and interleukin (IL)-6 receptor for desensitization in a sensitized nonhuman primate kidney transplantation model. All animals were sensitized using two sequential skin transplants from maximally major histocompatibility complex-mismatched donors. Carfilzomib (CFZ)/tocilizumab (TCZ) desensitization (N=6) successfully decreased donor-specific antibody (DSA) titers and prevented the expansion of B cells compared to CFZ monotherapy (N=3). Dual desensitization further delayed, but did not prevent humoral rebound, as evidenced by a delayed increase in post-kidney transplant DSA titers. Accordingly, CFZ/TCZ desensitization conferred a significant survival advantage over CFZ monotherapy. A trend toward increased T follicular helper cells was also observed in the dual therapy group along the same timeline as an increase in DSA and subsequent graft loss. Cytomegalovirus reactivation also occurred in the CFZ/TCZ group but was prevented with ganciclovir prophylaxis. In accordance with prior studies of CFZ-based dual desensitization strategies, the addition of IL-6 receptor blockade resulted in desensitization with further suppression of posttransplant humoral response compared to CFZ monotherapy.