UNASSIGNED: High interleukin-6 levels correlate with diseases like cancer, autoimmune disorders, and infections. IL-6 receptor inhibitors (IL-6Ri), used for rheumatoid arthritis and COVID-19, may have wider uses. We apply drug-target Mendelian Randomization (MR) to study IL-6Ri\'s effects.
UNASSIGNED: To simulate the effects of genetically blocking the IL-6R, we selected single nucleotide polymorphisms (SNPs) within or near the IL6R gene that show significant genome-wide associations with C-reactive protein. Using rheumatoid arthritis and COVID-19 as positive controls, our primary research outcomes included the risk of asthma, asthmatic pneumonia, cor pulmonale, non-small cell lung cancer, small cell lung cancer, Parkinson\'s disease, Alzheimer\'s disease, ulcerative colitis, Crohn\'s disease, systemic lupus erythematosus, type 1 diabetes, and type 2 diabetes. The Inverse Variance Weighted (IVW) method served as our principal analytical approach, with the hypotheses of MR being evaluated through sensitivity and colocalization analyses. Additionally, we conducted Bayesian Mendelian Randomization analyses to minimize confounding and reverse causation biases to the greatest extent possible.
UNASSIGNED: IL-6 inhibitors significantly reduced the risk of idiopathic pulmonary fibrosis (OR= 0.278, 95% [CI], 0.138-0.558; P <0.001), Parkinson\'s disease (OR = 0.354, 95% CI, 0.215-0.582; P <0.001), and positively influenced the causal relationship with Type 2 diabetes (OR = 0.759, 95% CI, 0.637-0.905; P = 0.002). However, these inhibitors increased the risk for asthma (OR = 1.327, 95% CI, 1.118-1.576; P = 0.001) and asthmatic pneumonia (OR = 1.823, 95% CI, 1.246-2.666; P = 0.002). The causal effect estimates obtained via the BWMR method are consistent with those based on the IVW approach. Similarly, sIL-6R also exerts a significant influence on these diseases.Diseases such as Alzheimer\'s disease, Crohn\'s disease, pulmonary heart disease, systemic lupus erythematosus, Type 1 diabetes, Non-small cell lung cancer and ulcerative colitis showed non-significant associations (p > 0.05) and were excluded from further analysis. Similarly, Small cell lung cancer were excluded due to inconsistent results. Notably, the colocalization evidence for asthmatic pneumonia (coloc.abf-PPH4 = 0.811) robustly supports its association with CRP. The colocalization evidence for Parkinson\'s disease (coloc.abf-PPH4 = 0.725) moderately supports its association with CRP.
UNASSIGNED: IL-6Ri may represent a promising therapeutic avenue for idiopathic pulmonary fibrosis, Parkinson\'s disease, and Type 2 diabetes.

Circular (circ) RNAs are non-coding RNAs with important functions in the nervous system, cardiovascular system, and cancer. Their role in atherosclerosis and myocardial infarction (MI) remains poorly described. We aim to investigate the potential circRNAs in immune cells during atherogenesis and examine the most regulated during MI and the modulation by interleukin (IL)-6 receptor inhibition by tocilizumab. Wild-type (WT) and ApoE-/- mice were fed an atherogenic diet for 10 weeks, and the circRNA profile was analyzed by circRNA microarray. Whole blood from patients with ST-elevated MI (STEMI) and randomized to tocilizumab (n = 21) or placebo (n = 19) was collected at admission, 3-7 days, and at 6 months, in addition to samples from healthy controls (n = 13). Primers for human circRNA were designed, and circRNA levels were measured using RT-qPCR. mRNA regulation of predicted circRNA targets was investigated by RNA sequencing. The expression of 867 circRNAs differed between atherogenic and WT mice. In STEMI patients, circUBAC2 was significantly lower than in healthy controls. CircANKRD42 and circUBAC2 levels were inversely correlated with troponin T, and for circUBAC2, an inverse correlation was also seen with final infarct size at 6 months. The predicted mRNA targets for circUBAC2 and circANKRD42 were investigated and altered levels of transcripts involved in the regulation of inflammatory/immune cells, apoptosis, and mitochondrial function were found. Finally, tocilizumab induced an up-regulation of circANKRD42 and circUBAC2 3-7 days after percutaneous coronary intervention. CircRNA levels were dysregulated in STEMI, potentially influencing the immune system, apoptosis, and mitochondrial function.

The IgG response against SARS-CoV-2 infection can persist for over six months (long response; LR). However, among 30% of those infected, the duration can be as short as three months or less (short response; SR). The present study assembled serological data on the anti-SARS-CoV-2 IgG response duration of two previous studies and integrated these results with the plasmatic cytokine levels and genetic profile of 10 immune-relevant SNPs that were also previously published, along with the plasmatic total IgG, IgA, and IgM levels, allowing for the genetic, clinical, immunological, and epidemiological aspects of the post-COVID-19 IgG response duration to be understood. The SR was associated with previous mild acute COVID-19 and with an SNP (rs2228145) in IL6R related to low gene expression. Additionally, among the SR subgroup, no statistically significant Spearman correlations were observed between the plasma levels of IL-17A and the Th17 regulatory cytokines IFN-γ (rs = 0.2399; p = 0.1043), IL-4 (rs = 0.0273; p = 0.8554), and IL-2 (rs = 0.2204; p = 0.1365), while among the LR subgroup, weaker but statistically significant Spearman correlations were observed between the plasma levels of IL-17A and IFN-γ (rs = 0.3873; p = 0.0016), IL-4 (rs = 0.2671; p = 0.0328), and IL-2 (rs = 0.3959; p = 0.0012). These results suggest that the Th17 response mediated by the IL-6 pathway has a role in the prolonged IgG response to SARS-CoV-2 infection.

Like TNFα, IL-6 is upregulated in Crohn\'s disease (CD) especially in patients associated with Mycobacterium avium paratuberculosis (MAP) infection, and both cytokines have been targeted as a therapeutic option for the treatment of the disease despite the accepted partial response in some patients. Limited response to anti-IL-6 receptor-neutralizing antibodies therapy may be related to the homeostatic dual role of IL-6. In this study, we investigated the effects and the signaling mechanism of IL-6 involved in intestinal epithelial integrity and function during MAP infection using an in vitro model that consists of THP-1, HT-29 and Caco-2 cell lines. Clinically, we determined that plasma samples from MAP-infected CD patients have higher IL-6 levels compared to controls (P-value < 0.001). In CD-like macrophages, MAP infection has significantly upregulated the secretion of IL-6 and the shedding of (IL-6R) from THP-1 macrophages, P-value < 0.05. Intestinal cell lines (Caco-2 and HT-29) were treated with the supernatant of MAP-infected THP-1 macrophages with or without a neutralizing anti-IL-6R antibody. Treating intestinal Caco-2 cells with supernatant of MAP-infected macrophages resulted in significant upregulation of intestinal damage markers including claudin-2 and SERPINE1/PAI-1. Interestingly, blocking IL-6 signaling exacerbated that damage and further increased the levels of the damage markers. In HT-29 cells, MAP infection upregulated MUC2 expression, a protective response that was reversed when IL-6R was neutralized. More importantly, blocking IL-6 signaling during MAP infection rescued damaged Caco-2 cells from MAP-induced apoptosis. The data clearly supports a protective role of IL-6 in intestinal epithelia integrity and function especially in CD patients associated with MAP infection. The findings may explain the ineffective response to anti-IL6 based therapy and strongly support a therapeutic option that restores the physiologic level of IL-6 in patient\'s plasma. A new treatment strategy based on attenuation of IL-6 expression and secretion in inflammatory diseases should be considered.

Considering the lack of consensus related to the impact of selective IL-6 receptor inhibition on bone remodeling and the scarcity of reports, especially on large bone defects, this study proposed to evaluate the biological impact of the selective inhibitor of interleukin-6 receptor (tocilizumab) in an experimental model of critical calvarial defect in rats. In this preclinical and in vivo study, 24 male Wistar rats were randomly divided into two groups (n=12/group): defect treated with collagen sponge (CG) and defect treated with collagen sponge associated with 2 mg/kg tocilizumab (TCZ). The defect in the parietal bone was created using an 8-mm diameter trephine drill. After 90 days, the animals were euthanized, and tissue samples (skull caps) were evaluated through micro-CT, histological, immunohistochemistry, cytokines, and RT-qPCR analyses. Tocilizumab reduced mononuclear inflammatory infiltration (P<0.05) and tumor necrosis factor (TNF)-α levels (P<0.01) and down-regulated tissue gene expression of BMP-2 (P<0.001), RUNX-2 (P<0.05), and interleukin (IL)-6 (P<0.05). Moreover, it promoted a stronger immunostaining of cathepsin and RANKL (P<0.05). Micro-CT and histological analyses revealed no impact on general bone formation (P>0.05). The bone cells (osteoblasts, osteoclasts, and osteocytes) in the defect area were similar in both groups (P>0.05). Tocilizumab reduced inflammatory cytokines, decreased osteogenic protein, and increased proteases in a critical bone defect in rats. Ninety days after the local application of tocilizumab in the cranial defect, we did not find a significant formation of bone tissue compared with a collagen sponge.

Cytokine release syndrome (CRS), commonly known as cytokine storm, is an acute systemic inflammatory response that is a significant global health threat. Interleukin-6 (IL-6) and interleukin-1 (IL-1) are key pro-inflammatory cytokines involved in CRS and are hence critical therapeutic targets. Current antagonists, such as tocilizumab and anakinra, target IL-6R/IL-1R but have limitations due to their long half-life and systemic anti-inflammatory effects, making them less suitable for acute or localized treatments. Here we present the de novo design of small protein antagonists that prevent IL-1 and IL-6 from interacting with their receptors to activate signaling. The designed proteins bind to the IL-6R, GP130 (an IL-6 co-receptor), and IL-1R1 receptor subunits with binding affinities in the picomolar to low-nanomolar range. X-ray crystallography studies reveal that the structures of these antagonists closely match their computational design models. In a human cardiac organoid disease model, the IL-1R antagonists demonstrated protective effects against inflammation and cardiac damage induced by IL-1β. These minibinders show promise for administration via subcutaneous injection or intranasal/inhaled routes to mitigate acute cytokine storm effects.

The cytokine interleukin-6 (IL-6) plays a crucial role in autoimmune and inflammatory diseases. Understanding the precise mechanism of IL-6 interaction at the amino acid level is essential to develop IL-6-inhibiting compounds. In this study, we employed computer-guided drug design tools to predict the key residues that are involved in the interaction between IL-6 and its receptor IL-6R. Subsequently, we generated IL-6 mutants and evaluated their binding affinity to IL-6R and the IL-6R - gp130 complex, as well as monitoring their biological activities. Our findings revealed that the R167A mutant exhibited increased affinity for IL-6R, leading to enhanced binding to IL-6R - gp130 complex and subsequently elevated intracellular phosphorylation of STAT3 in effector cells. On the other hand, although E171A reduced its affinity for IL-6R, it displayed stronger binding to the IL-6R - gp130 complex, thereby enhancing its biological activity. Furthermore, we identified the importance of R178 and R181 for the precise recognition of IL-6 by IL-6R. Mutants R181A/V failed to bind to IL-6R, while maintaining an affinity for the IL-6 - gp130 complex. Additionally, deletion of the D helix resulted in complete loss of IL-6 binding affinity for IL-6R. Overall, this study provides valuable insights into the binding mechanism of IL-6 and establishes a solid foundation for future design of novel IL-6 inhibitors.

OBJECTIVE: Interleukin 6 (IL-6) levels at hospital admission have been suggested for disease prognosis, and IL-6 antagonists have been suggested for the treatment of patients with severe COVID-19. However, less is known about the relationship between pre-COVID-19 IL-6 levels and the risk of severe COVID-19. To fill in this gap, here we extensively investigated the association of genetically instrumented IL-6 pathway components with the risk of severe COVID-19.
METHODS: We used a two-sample Mendelian randomization study design and retrieved genetic instruments for blood biomarkers of IL-6 activation, including IL-6, soluble IL-6 receptor, IL-6 signal transducer, and CRP, from respective large available GWASs. To establish associations of these instruments with COVID-19 outcomes, we used data from the Host Genetics Initiative and GenOMICC studies.
RESULTS: Our analyses revealed inverse associations of genetically instrumented levels of IL-6 and its soluble receptor with the risk of developing severe disease (OR = 0.60 and 0.94, respectively). They also demonstrated a positive association of severe disease with the soluble signal transducer level (OR = 1.13). Only IL-6 associations with severe COVID-19 outcomes reached the significance threshold corrected for multiple testing (p < 0.003; with COVID-19 hospitalization and critical illness).
CONCLUSIONS: These potential causal relationships for pre-COVID-19 IL-6 levels with the risk of developing severe symptoms provide opportunities for further evaluation of these factors as prognostic/preventive markers of severe COVID-19. Further studies will need to clarify whether the higher risk for a severe disease course with lower baseline IL-6 levels may also extend to other infectious diseases.

Protected biofactors and antioxidants (PBA), and protected biofactors and antioxidants with protected organic acids and essential oils (PBA+POAEO) have been shown to have benefits in stressed or challenged birds. Here, we describe the immunometabolic changes observed in the liver of Ross 308 broilers during feed supplementation and brief physiological stress. These studied additives contain protected essential oils, organic acids, and vitamins which may have protective effects on the liver. Thus, we aimed to determine the signaling changes induced by these supplements and the resultant immunometabolic effects in the liver. All birds received a 2X dose of live bronchitis vaccine at d 0 and a 48-h cold challenge by reducing the temperature from 30 to 32°C, to 20 to 23°C on d 3 to 5. Control birds were fed a standard diet without supplementation. Liver samples were collected to evaluate the effects of these treatments on cytokine gene expression and protein phosphorylation via kinome peptide array. ANOVA was used for statistical analysis of the gene expression data (significance at a p-value of 0.05), and PIIKA2 was used for statistical evaluation and comparative analysis of the kinome peptide array data. At d 15, the kinome peptide array analysis and gene expression data showed stimulation of the interleukin 6 receptor (IL-6R) signal transduction for host protection via heightened immune response while inducing immune modulation and reducing inflammation in both supplement treated groups. Significant changes were observed via IL-6R signaling in the metabolic profiles of both groups compared to control and no significant differences when compared to each other. In the liver, these 2 feed additives induced immunometabolic changes predominantly via the IL-6 receptor family signaling cascade. Differences between the 2 treated groups were predominantly in the metabolic pathways, centered around the mTOR pathway and the proteins AMPK, mTOR and S6K, with a more anabolic phenotype following the addition of essential oils.

BACKGROUND: M1 macrophages are closely associated with cardiac injury after myocardial infarction (MI). Increasing evidence shows that exosomes play a key role in pathophysiological regulation after MI, but the role of M1 macrophage-derived exosomes (M1-Exos) in myocardial regeneration remains unclear. In this study, we explored the impact of M1 macrophage-derived exosomes on cardiomyocytes regeneration in vitro and in vivo.
METHODS: M0 macrophages were induced to differentiate into M1 macrophages with GM-CSF (50 ng/mL) and IFN-γ (20 ng/mL). Then M1-Exos were isolated and co-incubated with cardiomyocytes. Cardiomyocyte proliferation was detected by pH3 or ki67 staining. Quantitative real-time PCR (qPCR) was used to test the level of miR-155 in macrophages, macrophage-derived exosomes and exosome-treated cardiomyocytes. MI model was constructed and LV-miR-155 was injected around the infarct area, the proliferation of cardiomyocytes was counted by pH3 or ki67 staining. The downstream gene and pathway of miR-155 were predicted and verified by dual-luciferase reporter gene assay, qPCR and immunoblotting analysis. IL-6 (50 ng/mL) was added to cardiomyocytes transfected with miR-155 mimics, and the proliferation of cardiomyocytes was calculated by immunofluorescence. The protein expressions of IL-6R, p-JAK2 and p-STAT3 were detected by Western blot.
RESULTS: The results showed that M1-Exos suppressed cardiomyocytes proliferation. Meanwhile, miR-155 was highly expressed in M1-Exos and transferred to cardiomyocytes. miR-155 inhibited the proliferation of cardiomyocytes and antagonized the pro-proliferation effect of interleukin 6 (IL-6). Furthermore, miR-155 targeted gene IL-6 receptor (IL-6R) and inhibited the Janus kinase 2(JAK)/Signal transducer and activator of transcription (STAT3) signaling pathway.
CONCLUSIONS: M1-Exos inhibited cardiomyocyte proliferation by delivering miR-155 and inhibiting the IL-6R/JAK/STAT3 signaling pathway. This study provided new insight and potential treatment strategy for the regulation of myocardial regeneration and cardiac repair by macrophages.