Interleukin-1 Receptor Research Articles

IL-7Rα on CD4+ T cells is required for their survival and the pathogenesis of experimental autoimmune encephalomyelitis

BackgroundThe IL-7 receptor alpha (IL-7Rα) binds both IL-7 and thymic stromal lymphopoietin (TSLP). IL-7Rα is essential for the development and survival of naive CD4+ T cells and their differentiation to effector/memory CD4+ T cells. Mice lacking IL-7Rα have severe lymphopenia and are resistant to experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis. However, it has been reported that IL-7Rα on peripheral CD4+ T cells is disposable for their maintenance and EAE pathogenesis, which does not align with the body of knowledge on the role of IL-7Rα in the biology of CD4+ T cells. Given that a definitive study on this important topic is lacking, we revisited it using a novel approach, an inducible knockout of the IL-7Rα gene in CD4+ T cells.MethodsWe generated Il7rafl/fl/CD4CreERT2 double transgenic mouse line (henceforth CD4ΔIl7ra), susceptible to tamoxifen-induced knockout of the IL-7Rα gene in CD4+ T cells. CD4ΔIl7ra mice were immunized with MOG35 − 55 for EAE induction and monitored for disease development. The expression of IL-7Rα, CD4+ T cell numbers, and MOG35 − 55-specific CD4+ T cell response was evaluated in the central nervous system (CNS) and lymphoid tissues by flow cytometry. Additionally, splenocytes of CD4ΔIl7ra mice were stimulated with MOG35 − 55 to assess their proliferative response and cytokine production by T helper cells.ResultsLoss of IL-7Rα from the surface of CD4+ T cells in CD4ΔIl7ra mice was virtually complete several days after tamoxifen treatment. The loss of IL-7Rα in CD4+ T cells led to a gradual and substantial decrease in their numbers in both non-immunized and immunized CD4ΔIl7ra mice, followed by slow repopulation up to the initial numbers. CD4ΔIl7ra mice did not develop EAE. We found a decrease in the total numbers of TNF-, IFN-γ-, IL-17 A-, and GM-CSF-producing CD4+ T cells and regulatory T cells in the spleens and CNS of immunized CD4ΔIl7ra mice. Tracking MOG35 − 55-specific CD4+ T cells revealed a significant reduction in their numbers in CD4ΔIl7ra mice and decreased proliferation and cytokine production in response to MOG35 − 55.ConclusionOur study demonstrates that IL-7Rα on peripheral CD4+ T cells is essential for their maintenance, immune response, and EAE pathogenesis.

Immunogenicity dynamics and covariate effects after satralizumab administration predicted with a hidden Markov model.

Immunogenicity is the propensity of a therapeutic protein to generate an immune response to itself. While reporting of antidrug antibodies (ADAs) is increasing, model-based analysis of such data is seldom performed. Model-based characterization of factors affecting the emergence and dissipation of ADAs may inform drug development and/or improve understanding in clinical practice. This analysis aimed to predict ADA dynamics, including the potential influence of individual covariates, following subcutaneous satralizumab administration. Satralizumab is a humanized IgG2 monoclonal recycling IL-6 receptor antagonist antibody approved for treating neuromyelitis optica spectrum disorder (NMOSD). Longitudinal pharmacokinetic (PK) and ADA data from 154 NMOSD patients in two pivotal Phase 3 studies (NCT02028884, NCT02073279) and PK data from one Phase 1 study (SA-001JP) in 72 healthy volunteers were available for this analysis. An existing population PK model was adapted to derive steady-state concentration without ADA for each patient. A mixed hidden Markov model (mHMM) was developed whereby three different states were identified: one absorbing Markov state for non-ADA developer, and two dynamic and inter-connected Markov states-transient ADA negative and positive. Satralizumab exposure and body mass index impacted transition probabilities and, therefore, the likelihood of developing ADAs. In conclusion, the mHMM model was able to describe the time course of ADA development and identify patterns of ADA development in NMOSD patients following treatment with satralizumab, which may allow for the formulation of strategies to reduce the emergence or limit the impact of ADA in the clinical setting.

Spesolimab, the first-in-class anti-IL-36R antibody: From bench to clinic.

Inflammatory diseases that are driven by several pro-inflammatory cytokines has resulted in in the development of targeted therapies across different disease settings. Interleukin (IL)-36 cytokines have been implicated in several inflammatory diseases. In this review we describe the scientific evidence surrounding the use of the IL-36 receptor (IL-36R)-targeting antibody, spesolimab, in IL-36-mediated skin diseases: generalized pustular psoriasis (GPP), palmoplantar pustulosis (PPP), hidradenitis suppurativa, and Netherton syndrome (NS). Spesolimab, a high affinity, specific, humanized, antagonistic immunoglobulin G1 antibody, targets the IL-36R at a binding site distinct from its agonists, IL-36α/β/γ, and at least one endogenous antagonist, IL-36R antagonist. Invitro and invivo data for spesolimab show effective inhibition of IL-36R-mediated signaling pathways, and six Phase I studies in healthy volunteers presented a favorable safety and pharmacokinetic (PK) profile, leading to the development of a clinical trial program to evaluate spesolimab in the treatment of IL-36R-mediated diseases. Six studies (including an expanded access program) have evaluated the efficacy, safety, PKs, and pharmacogenomics of spesolimab in patients with GPP flares. Spesolimab treatment of GPP flares resulted in rapid and sustained improvements in pustular and skin clearance, and clinically significant improvements in patient-reported symptoms and quality of life. Spesolimab also significantly reduces the risk of GPP flares and flare occurrence, preventing disease worsening and has a favorable safety profile. There have been three trials of spesolimab in PPP; further evaluation is needed to better define those patients who might benefit from the treatment. A trial of spesolimab in NS is ongoing, while other spesolimab trials suggest that IL-36 may only play a secondary role in the pathogenesis of atopic dermatitis. In conclusion, research into spesolimab has provided much needed insight into the role of IL-36 in the human immune system and the mechanism behind IL-36-mediated inflammatory diseases. Spesolimab provides an efficacious targeted treatment for GPP, a disease with a high unmet medical need.

Detection and Localization of IL-8 and CXCR1 in Rainbow Trout Larvae in Response to Pseudomonas aeruginosa Lipopolysaccharide

The salmonid industry faces challenges due to the susceptibility of fish to opportunistic pathogens, particularly in early developmental stages. Understanding the immunological capacity during these stages is crucial for developing effective disease control strategies. IL-8R, a member of the G-protein-coupled receptor family, acts as a receptor for Interleukin 8 (IL-8). The binding of IL-8 to IL-8R plays a major role in the pathophysiology of a wide spectrum of inflammatory conditions. This study focused on the immune response capacity of rainbow trout (Oncorhynchus mykiss) larvae by analyzing IL-8/CXCR1 response to lipopolysaccharide (LPS) from Pseudomonas aeruginosa. Previous research demonstrated that LPS from P. aeruginosa acts as a potent immunostimulant in teleost, enhancing pro-inflammatory cytokines. The methodology included in silico analysis and the synthesis and characterization of an omCXCR1-derived epitope peptide, which was used to produce omCXCR1-specific anti98 serum in mice. The research revealed that rainbow trout larvae 19 days post-hatching (dph) exhibited pronounced immune responses post-stimulation with 1 µg/mL of LPS. This was evidenced by the upregulated protein expression of IL-8 and omCXCR1 in trout larvae 2 and 8 h after LPS challenge, as analyzed by ELISA and immunohistochemistry. Furthermore, fluorescence microscopy successfully revealed the colocalization of IL-8 and its receptor in cells from mucosal tissues after LPS challenge in larvae 19 dph. These findings underscore the efficacy of LPS immersion as a method to activate the innate immune system in trout larvae. Furthermore, we propose IL-8 and its receptor as molecular markers for evaluating immunostimulation in the early developmental stages of salmonids.

Development of a Microfluidic Vascularized Osteochondral Model as a Drug Testing Platform for Osteoarthritis.

Osteoarthritis (OA) is a degenerative joint disease characterized by changes in cartilage and subchondral bone. To date, there are no available drugs that can counteract the progression of OA, partly due to the inadequacy of current models to recapitulate the relevant cellular complexity. In this study, an osteochondral microfluidic model is developed using human primary cells to mimic an OA-like microenvironment and this study validates it as a drug testing platform. In the model, the cartilage compartment is created by embedding articular chondrocytes in fibrin hydrogel while the bone compartment is obtained by embedding osteoblasts, osteoclasts, endothelial cells, and mesenchymal stem cells in a fibrin hydrogel enriched with calcium phosphate nanoparticles. After developing and characterizing the model, Interleukin-1β is applied to induce OA-like conditions. Subsequently, the model potential is evaluated as a drug testing platform by assessing the effect of two anti-inflammatory drugs (Interleukin-1 Receptor antagonist and Celecoxib) on the regulation of inflammation- and matrix degradation-related markers. The model responded to inflammation and demonstrated differences in drug efficacy. Finally, it compares the behavior of the "Cartilage" and "Cartilage+Bone" models, emphasizing the necessity of incorporating both cartilage and bone compartments to capture the complex pathophysiology of OA.

7657 Single Cell RNAseq And Omics Revealed Novel Role Of Liver Group 2 Innate Lymphocytes In Regulation Of Hepatic Gluconeogenesis

Abstract Disclosure: M. Fujimoto: None. T. Tanaka: None. Background: The liver is an important organ that maintains homeostasis of glucose metabolism in the body through gluconeogenesis. It is considered that gluconeogenesis in hepatocytes is particularly active around the portal vein. However, since excessive gluconeogenesis aggravates the pathogenesis of diabetes, it is necessary to elucidate the regulatory mechanism of gluconeogenesis. Although several studies revealed that group 2 innate lymphocytes (ILC2) contribute to blood glucose maintenance in adipose and pancreatic tissues, the contribution of liver ILC2s to glucose metabolism is unknown. This study aims to elucidate the contribution of liver ILC2s to glucose metabolism and its molecular mechanism. Methods: We administered IL-33, an endogenous ILC2 activator, to BALB/c and NSG mice, and measured fasting blood glucose levels and blood glucose elevation by gluconeogenic substrate pyruvate, and blood glucose levels in liver ILC2s transplanted NSG mice. Molecular mechanisms were analyzed by single cell-RNAseq (scRNA-seq) of liver ILC2s, lung ILC2s and hepatocytes, GATA3 transcription complex, ATAC-seq, GATA3-ChIP-seq, and Metabolomics of primary hepatocytes. Results: IL-33 strongly induced IL-13 production by liver ILC2s, lowered fasting blood glucose, and suppressed pyruvate-induced glucose elevation; these effects were not observed in NSG mice lacking immune cells including ILC2s. A hypoglycemic effect of IL-33 was observed in liver ILC2-transplanted NSG mice, but not in mice transplanted with IL-13-deficient ILC2s, suggesting the effect is IL-13-dependent. scRNA-seq results showed that liver ILC2s showed higher IL-13 expression than lung ILC2s, and IL-33 treatment suppressed the expression of gluconeogenic enzymes in the G6pc-high hepatocyte population. The interaction between liver ILC2s and G6pc-high hepatocytes via IL-13/IL-13 receptors was also demonstrated; co-culture of ILC2s with primary cultured hepatocytes resulted in decreased expression of hepatocyte gluconeogenic enzymes and accumulation of multiple gluconeogenic substrates. In addition, IL-13 neutralizing antibody treatment attenuated the effect of the decreased expression of gluconeogenic enzymes in hepatocytes. Transcription factor GATA3 complex analysis and GATA3-ChIPseq suggested binding of GATA3 of the AP-1 family (JunB) in liver ILC2s. Overexpression, knockdown, and scRNA-seq results suggest that AP1 may act in a GATA3-repressive manner in liver ILC2s. Discussion The functional characteristics of liver ILC2s, hepatocyte heterogeneity and subcluster were demonstrated by scRNA-seq, suggesting that liver ILC2s may directly suppress hepatocyte gluconeogenesis via IL-13. This may play a novel role in the homeostasis of hepatic glucose metabolism. Presentation: 6/1/2024

IL-13Rα2/TGF-β bispecific CAR-T cells counter TGF-β-mediated immune suppression and potentiate anti-tumor responses in glioblastoma.

Chimeric antigen receptor (CAR)-T cell therapies targeting glioblastoma (GBM)-associated antigens such as interleukin-13 receptor subunit alpha-2 (IL-13Rα2) have achieved limited clinical efficacy to date, in part due to an immunosuppressive tumor microenvironment (TME) characterized by inhibitory molecules such as transforming growth factor-beta (TGF-β). The aim of this study was to engineer more potent GBM-targeting CAR-T cells by countering TGF-β-mediated immune suppression in the TME. We engineered a single-chain, bispecific CAR targeting IL-13Rα2 and TGF-β, which programs tumor-specific T cells to convert TGF-β from an immunosuppressant to an immunostimulant. Bispecific IL-13Rα2/TGF-β CAR-T cells were evaluated for efficacy and safety against both patient-derived GBM xenografts and syngeneic models of murine glioma. Treatment with IL-13Rα2/TGF-β CAR-T cells leads to greater T-cell infiltration and reduced suppressive myeloid cell presence in the tumor-bearing brain compared to treatment with conventional IL-13Rα2 CAR-T cells, resulting in improved survival in both patient-derived GBM xenografts and syngeneic models of murine glioma. Our findings demonstrate that by reprogramming tumor-specific T-cell responses to TGF-β, bispecific IL-13Rα2/TGF-β CAR-T cells resist and remodel the immunosuppressive TME to drive potent anti-tumor responses in GBM.

IL-11-Engineered Macrophage Membrane-Coated Reactive Oxygen Species-Responsive Nanoparticles for Targeted Delivery of Doxorubicin to Osteosarcoma.

Osteosarcoma (OS) is a lethal malignant orthotopic bone tumor that primarily affects children and adolescents. Biomimetic nanocarriers have attracted wide attention as a new strategy for delivering chemotherapy agents to the OS. However, challenges such as rapid clearance and limited targeting hinder the effectiveness of OS chemotherapy. In this study, we designed reactive oxygen species (ROS)-responsive nanoparticles (NPs) coated with an interleukin (IL)11-engineered macrophage membrane (MM). The camouflage by MMs prevents clearance of IL-11-engineered MM-coated NPs loaded with doxorubicin (IL-11/MM@NPs/Dox) by the immune system. Moreover, the macrophage membrane combined with surface-expressed IL-11 not only directed IL-11/MM@NPs/Dox to OS tissues but also selectively identified IL-11 receptor alpha (IL-11Rα)-enriched OS cells. Within these cells, elevated levels of ROS triggered the controlled release of Dox from the ROS-responsive NPs. The synergistic modification of targeted ligand conjugation and cell membrane coating on the ROS-responsive NPs enhanced drug availability and reduced toxic side effects, thereby boosting the efficacy of OS chemotherapy. In summary, our findings suggest that IL-11/MM@NPs/Dox represents a promising approach to improving OS chemotherapy efficacy while ensuring excellent biocompatibility.

Ursolic Acid Regulates Immune Balance, Modulates Gut Microbial Metabolism, and Improves Liver Health in Mice.

Ursolic acid (UA) has demonstrated significant immunomodulatory and hepatoprotective effects; however, the underlying mechanisms remain unclear. This study aims to analyze the impact of UA on the gut microbiome, metabolome, and liver transcriptome, investigate UA's role in maintaining gut immune homeostasis and liver health, and evaluate the potential contributions of gut microbes and their metabolites to these beneficial effects. Our findings indicate that UA enhances immune balance in the jejunum, fortifies intestinal barrier function, and promotes overall gut health. UA modulates the intestinal microbiota and its metabolic processes, notably increasing the abundance of beneficial bacteria such as Odoribacter and Parabacteroides, along with their metabolites, including ornithine and lactucin. Additionally, UA inhibits the expression of interleukin-1 receptor 1 (IL1R1) and calcium (Ca2+) voltage-gated channel auxiliary subunit beta 2 (CACNB2) while enhancing the synthesis pathways of retinol and ascorbic acid, thereby exerting a protective influence on liver function. In summary, UA enhances intestinal immune homeostasis and promotes liver health, with these advantageous effects potentially mediated by beneficial bacteria (Odoribacter and Parabacteroides) and their metabolites (ornithine and lactucin).

Nanoenabled IL-15 Superagonist via Conditionally Stabilized Protein-Protein Interactions Eradicates Solid Tumors by Precise Immunomodulation.

Protein complexes are crucial structures that control many biological processes. Harnessing these structures could be valuable for therapeutic therapy. However, their instability and short lifespans need to be addressed for effective use. Here, we propose an innovative approach based on a functional polymeric cloak that coordinately anchors different domains of protein complexes and assembles them into a stabilized nanoformulation. As the polymer-protein association in the cloak is pH sensitive, the nanoformulation also allows targeting the release of the protein complexes to the acidic microenvironment of tumors for aiding their therapeutic performance. Building on this strategy, we developed an IL-15 nanosuperagonist (Nano-SA) by encapsulating the interleukin-15 (IL-15)/IL-15 Receptor α (IL-15Rα) complex (IL-15cx) for fostering synergistic transpresentation in tumors. Upon intravenous administration, Nano-SA stably circulated in the bloodstream, safeguarding the integrity of IL-15cx until reaching the tumor site, where it selectively released the active complex. Thus, Nano-SA significantly amplified the antitumor immune signals while diminishing systemic off-target effects. In murine colon cancer models, Nano-SA achieved potent immunotherapeutic effects, eradicating tumors without adverse side effects. These findings highlight the transformative potential of nanotechnology for advancing protein complex-based therapies.

Hypoglycemic drugs, circulating inflammatory proteins, and gallbladder diseases: A mediation mendelian randomization study

BackgroundThe relationship of hypoglycemic drugs, inflammatory proteins and gallbladder diseases remain unknown. MethodsFour hypoglycemic drugs were selected as exposure: glucagon-like peptide-1 receptor agonists (GLP-1RA), dipeptidyl peptidase-4 inhibitors (DPP-4i), sodium-glucose cotransporter 2 inhibitors (SGLT-2i), and metformin. The outcome were two gallbladder diseases: cholecystitis and cholelithiasis. Mendelian Randomization (MR) was employed to determine the association between hypoglycemic drugs and gallbladder diseases. ResultsDPP-4i and SGLT-2i had no effect on cholecystitis and cholelithiasis. However, a causal relationship was found between inhibition of ETFDH gene, a target of metformin expressed in cultured fibroblasts, and cholelithiasis (OR: 0.84, 95 %CI: (0.72,0.97), p = 0.021), as well as between GLP1R expression in the brain caudate basal ganglia and cholecystitis (OR: 1.29, 95 %CI: (1.11,1.49), p = 0.001). The effect of ETFDH inhibition on cholelithiasis through Interleukin-10 receptor subunit beta (IL-10RB) levels and Neurotrophin-3 (NT-3) levels, with a mediated proportion of 8 % and 8 %, respectively. ConclusionMetformin plays a protective role in cholelithiasis, while GLP-1RA have a harmful effect on the risk of cholecystitis. Metformin may reduce the risk of cholelithiasis by modulating the levels of Neurotrophin-3 (NT-3) and Interleukin-10 receptor subunit beta (IL-10RB). Further clinical and mechanistic studies are required to confirm these findings.

Randomized trial demonstrating no translocation of intact intestinal bacteria during hemodialysis or hemodiafiltration

IntroductionThe low incidence of intradialytic hypotension (IDH) in high-volume (HV) hemodiafiltration (HDF) may help maintaining gut perfusion during treatment. Preservation of gut endothelial integrity would limit or prevent bacterial translocation and subsequent systemic inflammation, which may contribute to the low mortality rate in HV-HDF. MethodsForty patients were cross-over randomized to S-HD, cool HD (C-HD) and HDF (low-volume [LV] and HV, convection volumes 15 L resp. ≥23 L/session), each for 2 weeks. Quantitative assessment of microbial DNA (mDNA) in blood was performed before and after dialysis by 16S-23S interspace profiling after DNA isolation. The intradialytic acute phase response (APR) was evaluated by high-sensitivity CRP (hs-CRP), IL-6 receptor (IL-6R), soluble CD14 (sCD14) and vascular-cell-adhesion molecule-1 (VCAM-1). Differences between modalities were primary objectives. ResultsMDNA was absent in all samples. IL-6R, sCD14, and VCAM-1 increased equally in all modalities (median increase resp.: 12.5%, 14.0%, 14.8%, P<0.05). Hs-CRP increased only in C-HD and HV-HDF (median increase: 12.6%, P<0.05). After correction for hemoconcentration, most APR-markers decreased (median: sCD14 -11.3% and VCAM-1 -14.4% in all modalities; IL-6R -13.4% in C-HD, LV- and HV-HDF; P<0.05). Hs-CRP only decreased in C-HD (-13.5%, P=0.004). Conclusions1) Circulating mDNA could not be demonstrated; 2) while in the crude analysis a similar APR was noted in all modalities, individual markers remained stable or declined after correction for hemoconcentration; 3) as neither bacterial translocation nor an APR was observed in either modality, it is highly unlikely that the superior survival of HV-HDF is explained by superior preservation of gut integrity.

Interleukin-2 receptor α (IL-2Rα/CD25) shedding is differentially regulated by N- and O-glycosylation

The cytokine interleukin-2 (IL-2) is a critical regulator of immune responses, with an especially well-characterized role in regulating T-cell homeostasis. IL-2 signaling involves three distinct receptor subunits: the IL-2Rα (CD25), IL-2Rβ, and IL-2Rγ. The intracellular transduction of IL-2-induced signals is strictly dependent on IL-2Rβ and IL-2Rγ, while the IL-2Rα is not directly involved in signaling. Instead, it has the highest affinity towards IL-2 and is thus responsible for regulating the affinity of a cell for IL-2. In addition to the membrane-bound IL-2Rα, a soluble form of the receptor (sIL-2Rα) has been described, which is present in the blood of healthy individuals, increased under various pathological conditions, and able to bind IL-2 and thus modulate its function. The sIL-2Rα is generated by proteolytic cleavage of the membrane-bound receptor. Here, we analyze whether glycosylation of the IL-2Rα regulates its proteolysis. We find that constitutive IL-2Rα shedding is affected by glycosylation and discover distinct roles for N- and O-glycosylation. Furthermore, we show that induced shedding by the metalloproteases ADAM10 and ADAM17 is also differentially regulated by distinct types of glycans. Finally, we identify a specific role for an N-glycan at an exosite in ADAM17-mediated proteolysis that does not affect ADAM10, indicating distinct substrate recognition mechanisms. These results further the understanding of the mechanisms leading to sIL-2Rα generation, and thus offer the opportunity to specifically modulate the generation of the soluble receptor.

Bidirectional interaction between IL and 17A/IL-17RA pathway dysregulation and α-synuclein in the pathogenesis of Parkinson’s disease

Parkinson’s disease (PD) pathogenesis is characterized by α-synuclein (α-syn) pathology, which is influenced by various factors such as neuroinflammation and senescence. Increasing evidence has suggested a pivotal role for Interleukin-17A(IL-17A) and Interleukin-17 Receptor A (IL-17RA) in PD, yet the trigger and impact of IL-17A/IL-17RA activation in PD remains elusive. This study observed an age-related increase in IL-17A and IL-17RA in the human central nervous system, accompanied by increased α-syn and senescence biomarkers. Interestingly, both levels of IL-17A and IL-17RA in PD patients were significantly elevated compared to age-matched controls, wherein the IL-17A was mainly present in neurons. This abnormal neuronal IL-17A activation in the PD brain was recapitulated in α-syn mouse models. Correspondingly, administration of recombinant IL-17A exacerbated pathological α-syn in both neuron and mouse models. Furthermore, IL-17A/IL-17RA pathway interventions via blocking antibody or shRNA-mediated knockdown can mitigate the effects of pathological α-syn. This study reveals an interplay between dysregulation of the IL-17A/IL-17RA pathway and α-syn, suggesting that regulating the IL-17A/IL-17RA pathway could modify PD progression by disrupting the detrimental cycle.

Another Notch in the Belt of Rheumatoid Arthritis.

Notch ligands and receptors, including JAG1/2, DLL1/4, and Notch1/3, are enriched on macrophages (MΦs), fibroblast-like synoviocytes (FLS), and/or endothelial cells in rheumatoid arthritis (RA) compared with normal synovial tissues (ST). Power Doppler ultrasound-guided ST studies reveal that the Notch family is highly involved in early active RA, especially during neovascularization. In contrast, the Notch family is not implicated during the erosive stage, evidenced by their lack of correlation with radiographic damage in RA ST. Toll-like receptors and tumor necrosis factor (TNF) are the common inducers of Notch expression in RA MΦs, FLS, and endothelial cells. Among Notch ligands, JAG1 and/or DLL4 are most inducible by inflammatory responses in RA MΦs or endothelial cells and transactivate their receptors on RA FLS. TNF plays a central role on Notch ligands, as anti-TNF good responders display JAG1/2 and DLL1/4 transcriptional downregulation in RA ST myeloid cells. In in vitro studies, TNF increases Notch3 expression in MΦs, which is further amplified by RA FLS addition. Specific disease-modifying antirheumatic drugs reduced JAG1 and Notch3 expression in MΦ and RA FLS cocultures. Organoids containing FLS and endothelial cells have increased expression of JAG1 and Notch3. Nonetheless, Methotrexate, interleukin-6 receptor (IL-6R) antibodies, and B cell blockers are mostly ineffective at decreasing Notch family expression. NF-κB, MAPK, and AKT pathways are involved in Notch signaling, whereas JAK/STATs are not. Although Notch blockade has been effective in RA preclinical studies, its small molecule inhibitors have failed in phase Iand II studies, suggesting that alternative strategies may be required to intercept their function.

Pharmacological inhibition reveals participation of the endocytic compartment in positive feedback IL-6 secretion in human skeletal myotubes

IL-6 is an important cytokine involved in metabolic, immunological, and cell-fate responses. It is released upon stimulation by skeletal muscle cells through partially characterized mechanisms. In some cell types, IL-6 has been reported to activate a positive feedback loop involving endocytic vesicles, but evidence is mostly based on transcription and signal transduction mechanisms and is very scarce in muscle cells. Our aim was to directly demonstrate the presence of positive feedback in the ATP-induced release of IL-6 into the supernatant of human skeletal muscle cultures. The total release (production) of IL-6 was reduced for higher volumes of supernatant, when the secreted IL-6 molecules are more diluted, and enhanced when the supernatant volume was lower. In addition, secretion was impaired both by tocilizumab, a blocker of human IL-6 receptors, and by the soluble form of the receptor. The secretion in response to ATP was also inhibited by treatment with the endocytosis inhibitor dynasore, and by disruption of the acidic gradient of the endocytic compartment using different methods (chloroquine, NH4Cl or monensin). IL-6 secretion was also impaired by NED-19, a specific inhibitor of the two pore channels receptor mediating Ca2+ release from the endolysosomal compartment. IL-6 and ATP increased IL-6 mRNA levels, an effect blocked by tocilizumab. Altogether, our results demonstrate that ATP-secreted IL-6 activates a positive loop based on IL-6 receptors, endocytosis, two pore channels and IL-6 transcription. Given the importance of muscle IL-6 as a systemic regulator and as an inflammatory mediator, our study can help to understand muscle pathophysiology.

Over Activation of IL-6/STAT3 Signaling Pathway in Juvenile Dermatomyositis.

Juvenile dermatomyositis (JDM) is characterized by persistent non-purulent inflammation in the muscle and skin. The underlying mechanisms still remain uncertain. This study aims to elucidate the mechanism of interleukin-6 (IL-6) activation of Janus kinase/signal transducer and activator of transcription 3 pathway (JAK/STAT3), contributing to the pathogenesis of JDM. Serum IL-6 levels were compared between 72 newly diagnosed patients with JDM and the same patient cohort in treatment remission. Single-cell RNA sequencing (scRNA-seq) was employed to identify differential signaling pathway expression in muscle biopsy samples from two patients with JDM and healthy controls. Immunohistochemistry was used to examine differences in STAT3 phosphorylation between JDM and control muscle tissues. In vitro, skeletal muscle cell lines were stimulated with IL-6, and the transcription levels of genes related to mitochondrial calcium channels were quantified via reverse transcription-polymerase chain reaction (RT-PCR). Reactive oxygen species (ROS) production was measured in both IL-6 treated and untreated groups. ROS levels were then compared between IL-6 receptor antagonist pre-treated skeletal muscle cells and untreated cells. IL-6 levels in newly onset patients with JDM were significantly higher compared to the same patient cohort in remission states (p < 0.0001). Serum IL-6 was significantly increased in patients with negative myositis specific antibody (MSA), positive melanoma differentiation associated protein 5 (MDA5) and positive nuclear matrix protein 2 (NXP2), yet not for JDM with positive transcriptional intermediary factor γ(TIF1γ), based on subgroup analysis. ScRNA-seq analysis of muscle biopsies from patients with MDA5-positive JDM and patients with MSA negative JDM revealed abnormal activation of the JAK/STAT3 pathway in skeletal myocytes, macrophages, and vascular endothelial cells. The phosphorylation levels of STAT3 were elevated in active JDM cases. Transcription of the calcium channel modulation gene sarcolipin (SLN) was significantly higher in JDM primary skeletal muscle cells compared to normal cells. In vitro, IL-6 enhanced SLN transcription and induced ROS production, and blocking the IL-6 receptor resulted in decreased ROS generation in skeletal muscle cells. IL-6/JAK/STAT3 signaling pathway was abnormally activated in patients with JDM. IL-6 may be involved in the pathogenesis of muscle damage by triggering the development of calcium overload and production of ROS. Blockade of the IL-6/JAK/STAT3 pathway can be a potential treatment option for JDM, especially MDA5-positive patients and those who are negative for MSA.

NMOSD and MOGAD: an evolving disease spectrum.

Neuromyelitis optica (NMO) spectrum disorder (NMOSD) is a relapsing inflammatory disease of the CNS, characterized by the presence of serum aquaporin 4 (AQP4) autoantibodies (AQP4-IgGs) and core clinical manifestations such as optic neuritis, myelitis, and brain or brainstem syndromes. Some people exhibit clinical characteristics of NMOSD but test negative for AQP4-IgG, and a subset of these individuals are now recognized to have serum autoantibodies against myelin oligodendrocyte glycoprotein (MOG)-a condition termed MOG antibody-associated disease (MOGAD). Therefore, the concept of NMOSD is changing, with a disease spectrum emerging that includes AQP4-IgG-seropositive NMOSD, MOGAD and double-seronegative NMOSD. MOGAD shares features with NMOSD, including optic neuritis and myelitis, but has distinct pathophysiology, clinical profiles, neuroimaging findings (including acute disseminated encephalomyelitis and/or cortical encephalitis) and biomarkers. AQP4-IgG-seronegative NMOSD seems to be a heterogeneous condition and requires further study. MOGAD can manifest as either a monophasic or a relapsing disease, whereas NMOSD is usually relapsing. This Review summarizes the history and current concepts of NMOSD and MOGAD, comparing epidemiology, clinical features, neuroimaging, pathology and immunology. In addition, we discuss new monoclonal antibody therapies for AQP4-IgG-seropositive NMOSD that target complement, B cells or IL-6 receptors, which might be applied to MOGAD in the near future.

Interleukin-2 receptor signaling acts as a checkpoint that influences the distribution of regulatory T cell subsets

Interleukin-2 receptor signaling acts as a checkpoint that influences the distribution of regulatory T cell subsets

Anti-thymocyte Globulin (ATG) vs. Interleukin-2 Receptor Antagonist (IL-2 RA) in Low Immunologic-Risk Kidney Transplant Recipients

Anti-thymocyte Globulin (ATG) vs. Interleukin-2 Receptor Antagonist (IL-2 RA) in Low Immunologic-Risk Kidney Transplant Recipients