IL-6 Production Research Articles

Anti-inflammatory effects of a methanol extract from Montanoa grandiflora DC. (Asteraceae) leaves on in vitro and in vivo models.

Montanoa grandiflora, a plant species native from Mexico to Central America, locally known as "Teresita" in Yucatán, México, is used to alleviate anxiety, rheumatism, and stomach issues. This study aims to investigate the anti-inflammatory properties of the methanol extract of Montanoa grandiflora leaves (MMG) in experimental models of inflammation. Gas chromatography-mass spectroscopy was used to characterize the MMG; cytotoxicity was assessed by MTT assay on murine macrophages and hemolysis assay. The in vitro anti-inflammatory activity was evaluated on LPS-stimulated murine macrophages by measuring of pro- and anti-inflammatory cytokines, NO and H2O2 release. The in vivo anti-inflammatory activity was evaluated using carrageenan-induced mouse paw edema, 12-O-tetradecanoylphorbol 13-acetate induced-ear edema, and 1-fluoro-2,4-dinitrobenzene induced-delayed-type hypersensitivity. In addition, the serum levels of prostaglandins and leukotrienes were assessed. The main compounds found in MMG were terpenes (i.e., β-caryophyllene, (-)-α-cubebene, alloaromadendrene, ( +)-δ-cadinene, β-eudesmol), alkaloid (( ±)-nor-β-hydrastine), cyclic polyol (quinic acid), carbohydrates and their derivatives, and fatty acids (octadecatrienoic acid and octadecanoic acid). MMG did not exhibit cytotoxic or hemolytic activity. However, it demonstrated in vitro anti-inflammatory effects by increasing the production of IL-10, decreasing the levels of TNF-α, IL-1β, IL-6, NO and H2O2. MMG significantly reduced carrageenan-induced paw edema, TPA-induced ear edema, and DNFB-induced delayed-type hypersensitivity in mice with effects comparable to those of standard drugs, as well as serum levels of prostaglandins and leukotrienes. The anti-inflammatory activity of MMG is associated with increased IL-10 levels and inhibiting inflammatory cell migration mechanisms, without causing cytotoxic or hemolytic damage in both in vitro and in vivo assays.

Toll-like receptor 2-mediated ERK activation significantly upregulates interleukin-6 expression in M2-polarized macrophages

Abstract Objectives M2-polarized macrophages and interleukin (IL)-6 significantly alter the tumor microenvironment and promote the malignant behaviors of tumor cells. This study aimed to establish M2-type macrophages from THP-1 cells, which are human leukemia monocytes, and investigate the significance of toll-like receptor 2 (TLR2) signaling in IL-6 production. Methods THP-1 cells were treated with phorbol 12-myristate 13-acetate, IL-4, and IL-13 to stimulate their differentiation into M2 macrophages. Cell differentiation was confirmed by cytokine production, marker expression, and morphological alterations. Treatment with TLR agonists induced TLR stimulation in M2 macrophages. Subsequently, secretion and expression levels of IL-6 in M2 macrophages were measured using enzyme-linked immunosorbent assay, quantitative reverse transcription-polymerase chain reaction, and western blotting. Results Myeloid differentiation factor 88, tumor necrosis factor-associated factor 6, and IL-1 receptor-associated kinase-1/4 signaling pathways contributed to IL-6 production upon TLR2 activation in M2 macrophages. While both TLR2 and TLR4 activated NF-κB in M2 macrophages, IL-6 production was mainly dependent on TLR2, not TLR4, suggesting the involvement of major mechanisms other than NF-κB in IL-6 production. Notably, TLR2-stimulated extracellular signal-regulated kinase (ERK) was necessary for abundant IL-6 production, indicating that TLR2-mediated ERK signaling plays an essential role in M2 macrophages. Conclusions These results highlight the significance of TLR2 signaling in IL-6 production by M2 macrophages and provide insights into the underlying regulatory mechanisms.

Proteomic approach to identify host cell attachment proteins provides protective Pseudomonas aeruginosa vaccine antigen FtsZ

Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that causes severe nosocomial infections in susceptible individuals due to the emergence of multidrug-resistant strains. There are no approved vaccines against P. aeruginosa infections nor candidates in active clinical development, highlighting the need for novel candidates and strategies. Using a cell-blot proteomic approach, we reproducibly identified 49 proteins involved in interactions with human lung epithelial cells across four P. aeruginosa strains. Among these were cell division protein FtsZ and outer membrane protein OpmH. Escherichia coli BL21 cells overexpressing recombinant FtsZ or rOpmH showed a 66- and 15-fold increased ability to attach to 16HBE14o− cells, further supporting their involvement in host cell attachment. Both antigens led to proliferation of NK and CD8+ cytotoxic T cells, significant increases in the production of IFN-γ, IL-17A, TNF and IL-4 in immunised mice and elicited strong antigen-specific serological IgG1 and IgG2c responses. Immunisation with FtsZ significantly reduced bacterial burden in the lungs by 1.9-log CFU and dissemination to spleen by 1.8-log CFU. The protective antigen candidate, FtsZ, would not have been identified by traditional approaches relying on either virulence mechanisms or sequence-based predictions, opening new avenues in the development of an anti-P. aeruginosa vaccine.

Fecal microbiota transplantation from protozoa-exposed donors downregulates immune response in a germ-free mouse model, its role in immune response and physiology of the intestine.

Intestinal parasites are part of the intestinal ecosystem and have been shown to establish close interactions with the intestinal microbiota. However, little is known about the influence of intestinal protozoa on the regulation of the immune response. In this study, we analyzed the regulation of the immune response of germ-free mice transplanted with fecal microbiota (FMT) from individuals with multiple parasitic protozoans (P) and non-parasitized individuals (NP). We determined the production of intestinal cytokines, the lymphocyte populations in both the colon and the spleen, and the genetic expression of markers of intestinal epithelial integrity. We observed a general downregulation of the intestinal immune response in mice receiving FMT-P. We found significantly lower intestinal production of the cytokines IL-6, TNF, IFN-γ, MCP-1, IL-10, and IL-12 in the FMT-P. Furthermore, a significant decrease in the proportion of CD3+, CD4+, and Foxp3+ T regulatory cells (Treg) was observed in both, the colon and spleen with FMT-P in contrast to FMT-NP. We also found that in FMT-P mice there was a significant decrease in tjp1 expression in all three regions of the small intestine; ocln in the ileum; reg3γ in the duodenum and relmβ in both the duodenum and ileum. We also found an increase in colonic mucus layer thickness in mice colonized with FMT-P in contrast with FMT-NP. Finally, our results suggest that gut protozoa, such as Blastocystis hominis, Entamoeba coli, Endolimax nana, Entamoeba histolytica/E. dispar, Iodamoeba bütschlii, and Chilomastix mesnili consortia affect the immunoinflammatory state and induce functional changes in the intestine via the gut microbiota. Likewise, it allows us to establish an FMT model in germ-free mice as a viable alternative to explore the effects that exposure to intestinal parasites could have on the immune response in humans.

Selenopolysaccharide Isolated from Lentinula edodes Mycelium Affects Human T-Cell Function

Lentinula edodes polysaccharides are natural immunomodulators. SeLe30, analyzed in this study, is a new mixture of selenium-enriched linear 1,4-α-glucans and 1,3-β- and 1,6-β-glucans isolated from L. edodes mycelium. In the present study, we evaluated its immunomodulatory properties in human T cells. Peripheral blood mononuclear cells (PBMCs) and T cells were isolated from healthy donors’ buffy coats. The effects of SeLe30 on CD25, CD366, and CD279 expression, the subsets of CD8+ T cells, and IFN-γ, IL-6, and TNF-α production were analyzed. SeLe30 downregulated CD25, CD279, and CD366 expression on T cells stimulated by the anti-CD3 antibody (Ab) and upregulated in unstimulated and anti-CD3/CD28-Abs-stimulated T cells. It increased the percentage of central memory CD8+ T cells in unstimulated PBMCs and naïve and central memory T cells in anti-CD3-Ab-stimulated PBMCs. SeLe30 decreased the number of central memory and naïve CD8+ T cells in anti-CD3/CD28-stimulated T cells, whereas, in PBMCs, it reduced the percentage of effector memory CD8+ T cells. Moreover, SeLe30 upregulated cytokine production. SeLe30 exhibits context-dependent effects on T cells. It acts on unstimulated T cells, affecting their activation while increasing the expression of immune checkpoints, which sensitizes them to inhibitory signals that can silence this activation. In the case of a lack of costimulation, SeLe30 exhibits an inhibitory effect, reducing T-cell activation. In cells stimulated by dual signals, its effect is further enhanced, again increasing the “safety brake” of CD366 and CD279. However, the final SeLe30 effect is mediated by its indirect impacts by altering interactions with other immune cells.

Stretched Vascular Endothelial Cells Polarized Neutrophils to N2 Type via TRPC1-IL13-STAT3 Axis.

VECs play a crucial role in regulating the function of neutrophils, which is essential for immune responses and inflammation. As stretch-sensitive cells, VECs sense mechanical stretch through surface mechanoreceptors, converting external mechanical stimuli into biochemical signals. This study aimed to explore the molecular mechanisms underlying the regulation of neutrophil behavior by stretched VECs. The key cytokine-inducing neutrophil N2 polarization in the conditioned medium from stretched vascular endothelial cells (CM-stretch) was validated through multifactorial matrix and flow cytometry. Additionally, the molecular mechanism underlying the response of vascular endothelial cells to stretch was systematically verified through layer-by-layer analysis using WB. IL13, not IL4, was ultimately identified as a key cytokine-inducing neutrophil N2 polarization in CM-stretch. Inhibition of the transient receptor potential channel (TRPC1) and siRNA-mediated knockdown of TRPC1 both significantly decreased IL13 production. Furthermore, neutralizing IL13 in the CM-stretch or inhibiting STAT3 phosphorylation inhibited neutrophil N2 polarization, as evidenced by reduced CD206 and VEGFA expression. These results demonstrate that stretched VECs initiate a signaling cascade that induces neutrophil N2 polarization through the TRPC1-IL13-STAT3 axis, suggesting that mechanical stretching of VECs could shift neutrophil function from a pro-inflammatory to a more regulatory and healing role.

Characteristics of the proinflammatory response of monocytes/macrophages in patients with metabolic syndrome, exemplified by the production of IL-6 and MCP-1

Metabolic syndrome (MS) is one of the most common socially significant diseases. Around 1.9 billion people suffer from this disease, which places an enormous burden on healthcare systems around the world. This is particularly true in connection with concomitant diseases. With the progression of MS, disorders in the function of the immune system occur in the body, including those associated with mitochondrial dysfunction, leading to the development of chronic inflammation. In particular, there is an increase in the number of circulating monocytes actively recruited to inflamed adipose tissue, where there is non-specific proinflammatory activation of innate immune cells, which adopt an M1-like phenotype and become less sensitive to anti-inflammatory stimuli. This ultimately leads to a decrease in the functional activity of monocytes/macrophages and their immunoplasticity. The subject of the study was the venous blood of patients and the CD14+ monocytes/macrophages obtained from it by immunomagnetic separation. In our work, we focused on the search for significant relationships between markers of chronic inflammation and the formation of immune tolerance of monocytes/macrophages in patients with metabolic syndrome. Biochemical parameters, basal and LPS-stimulated production of proinflammatory cytokines (IL-6 and MCP-1) were investigated by culture of monocytes/macrophages in patients with metabolic syndrome. The evaluation of biochemical parameters in blood samples from MS patients and healthy donors revealed that the levels of ALAT, AST, GGT, alkaline phosphatase, uric acid, C-reactive protein, glucose and insulin were significantly higher in MS patients than in healthy donors. The levels of P-amylase and high-density lipoprotein were significantly lower than in the control group. Within the experimental model, repeated stimulation showed a decrease in cytokine production in response to LPS compared to the first stimulation on day 7. It was also found that the response to the primary stimulus was higher in cells from patients with a body mass index (BMI) 40 kg/m2, which could indirectly indicate the presence of a phenotype associated with chronic inflammation and consequently with reduced plasticity of the monocyte/macrophage immune response.

Differential Adjuvant Activity by Flagellins from Escherichia coli, Salmonella enterica Serotype Typhimurium, and Pseudomonas aeruginosa

(1) Background: The adjuvant properties of flagellin from various bacterial species have been extensively studied; however, a systematic comparison of the immunoadjuvant effects of flagellins from different bacterial species is lacking. This study aims to analyze the amino acid sequences and structural features of flagellins from Escherichia coli (FliCE.C), Salmonella enterica serotype Typhimurium (FliCS.T), and Pseudomonas aeruginosa (FliCP.A), and to evaluate their adjuvant activities in terms of Toll-like receptor 5 (TLR5) activation, antibody production, and cytokine responses in a murine model. (2) Methods: Bioinformatics analysis was conducted to compare the amino acid sequences and structural domains (D0, D1, D2, and D3) of flagellins from the three bacterial species. PyMol atomic models were used to confirm structural differences. Toll-like receptor 5 (TLR5) activation assays were performed to measure IL-8 and TNF-α production in vitro. The IgG antibody titers against the model antigen FaeG and cytokine responses, including IL-4 and TNF-α secretion were evaluated in a murine model. (3) Results: Bioinformatics analysis revealed that the D0 and D1 domains are highly conserved, whereas the D2 and D3 domains exhibit significant variability across the three species. Structural analysis via PyMol confirmed these differences, particularly in the D2 and D3 domains. TLR5 activation assays showed that FliCS.T and FliCP.A induced higher levels of IL-8 and TNF-α production compared to FliCE.C, indicating species-specific variations in TLR5 activation. In the murine model, FliCS.T as an adjuvant produced higher antibody titers against FaeG and increased IL-4 secretion in splenocytes compared to FliCE.C and FliCP.A. FliCP.A induced higher TNF-α expression than FliCS.T and FliCE.C, suggesting FliCS.T and FliCP.A are more effective at inducing T-cell responses. (4) Conclusions: This study highlights the potential of FliCS.T and FliCP.A as potent vaccine adjuvants. The results provide insights into the structure–function relationships of these flagellins and support their application in enhancing immune responses against diverse pathogens.

Brazilian red propolis synergistically with imipenem modulates immunological parameters and the bactericidal activity of human monocytes against methicillin-resistant Staphylococcus aureus (MRSA).

Propolis is a bee product found all over the globe and has a well-known antibacterial activity. Previous findings of our group revealed that the combination of Brazilian red propolis (BRP) with a lower concentration of imipenem (IPM) exerted a bactericidal action against methicillin-resistant Staphylococcus aureus (MRSA) in vitro. Here, we aimed at investigating the effects of BRP in combination or not with IPM on human monocytes to assess a possible immunomodulatory action. Monocyte metabolic activity was analysed by MTT assay, cytokine production (TNF-α, IL-1β, IL-6, IL-8, and IL-10) by ELISA, and the expression of cell markers (TLR-2, TLR-4, HLA-DR, and CD80) by flow cytometry. The bactericidal activity of monocytes over MRSA was determined by colony-forming units' count. BRP alone or in combination with IPM exerted no cytotoxic effects on monocytes. BRP downregulated TLR-2 expression and inhibited TNF-α, IL-1β, and IL-6 production, while BRP + IPM stimulated these parameters. BPR alone or in combination increased the bactericidal activity similarly to LPS-activated monocytes. Data indicated the potential of BRP as an anti-inflammatory agent increasing the bactericidal activity of monocytes against MRSA. The combination of BRP + IPM exhibited a stimulatory profile that may be potentially useful in treating patients with MRSA infection.

Machine learning-based new classification for immune infiltration of gliomas.

Glioma is a highly heterogeneous and poorly immunogenic malignant tumor, with limited efficacy of immunotherapy. The characteristics of the immunosuppressive tumor microenvironment (TME) are one of the important factors hindering the effectiveness of immunotherapy. Therefore, this study aims to reveal the immune microenvironment (IME) characteristics of glioma and predict different immune subtypes using machine learning methods, providing guidance for immune therapy in glioma. We first performed unsupervised cluster analysis on the genes and arrays of 693 gliomas in CGGA database and 702 gliomas in TCGA database. Then establish and verify the classification model through Machine Learning (ML). Then, use DAVID to perform functional enrichment analysis for different immune subtypes. Next step, analyze the immune cell distribution, stemness maintenance, mesenchymal phenotype, neuronal phenotype, tumorigenic cytokines, molecular and clinical characteristics of different immune subtypes of gliomas. Firstly, we divide the IME of gliomas in the CGGA database into four different subtypes, namely IM1, IM2, IM3, and IM4; similarly, the IME of gliomas in the TCGA database can also be divided into four different subtypes (IMA, IMB, IMC, and IMD). Next, based on ML, we developed a highly reliable model for predicting different immune subtypes of glioma. Then, we found that Monocytic lineage, Myeloid dendritic cells, NK cells and CD8 T cells had the highest enrichment in the IM1/IMD subtypes. Cytotoxic lymphocytes were highest expressed in the IM4/IMA subtypes. Next step, Enrichment analysis revealed that the IM1-IMD subtypes were mainly closely related to the production and secretion of IL-8 and TNF signaling pathway. The IM2-IMB subtypes were strongly associated with leukocyte activation and NK cell mediated cytotoxicity. The IM3-IMC subtypes were closely related to mitotic nuclear division and mitotic cell cycle process. The IM4-IMA subtypes were strongly associated with Central Nervous System (CNS) development and striated muscle tissue development. Afterwards, Single sample gene set enrichment analysis (ssGSEA) showed that stemness maintenance phenotypes were mainly enriched in the IM4/IMA subtypes; Neuronal phenotypes were closely associated with the IM2/IMB subtypes; and mesenchymal phenotypes and tumorigenic cytokines were highly correlated with the IM2 /IMB subtypes. Finally, we found that compared with patients in the IM2/IMB and IM4/IMA subtypes, the IM1/IMD and IM3/IMC subtypes have the highest proportion of GBM patients, the shortest average overall survival of patients and the lowest proportion of patients with IDH mutation and 1p36/19q13 co-deletion. We developed a highly reliable model for predicting different immune subtypes of glioma by ML. Then, we comprehensively analyzed the immune infiltration, molecular and clinical features of different immune subtypes of gliomas and defined gliomas into four subtypes: immunogenic subtype, adaptive immune resistance subtype, mesenchymal subtype, and immune tolerance subtype, which represent different TMEs and different stages of tumor development.

The protective effect and immunomodulatory ability of orally administrated Lacticaseibacillus rhamnosus GG against Mycoplasma pneumoniae infection in BALB/c mice.

Mycoplasma pneumoniae represents one of the significant etiologies of community-acquired pneumonia in pediatric patients. However, clinical treatment of M. pneumoniae infection in children has encountered challenges due to the escalating resistance to quinolones. Numerous studies have highlighted the potential of probiotic lactobacillus administration in boosting immune responses to bacterial and viral respiratory infections. In this study, the protective efficacy of pre-oral administration of Lacticaseibacillus rhamnosus GG (LGG), Limosilactobacillus reuteri F275, Lactiplantibacillus plantarum NCIMB 8826, L. plantarum S1 or L. plantarum S2 was evaluated in the BALB/c mice model; it was observed that among these five strains of lactobacillus, the supplementation of LGG exhibited the most significant protective effect against M. pneumoniae infection. Moreover, when administered orally, both live LGG and heat-inactivated LGG have demonstrated efficacy in reducing the burden of M. pneumoniae in the lungs and alleviating pulmonary inflammation. Oral supplementation with LGG resulted in the inhibition of neutrophil recruitment into the lungs and increased recruitment of alveolar macrophages in M. pneumoniae-infected mice. Additionally, LGG supplementation led to increased production of IL-10 and secretory IgA (sIgA), while suppressing the levels of IL-1β, IL-6, IL-17A, and TNF-α in the lungs of mice infected with M. pneumoniae. The data suggests that supplementation with LGG can modulate immune responses, decrease pathogen load, and alleviate inflammatory injury in the lungs of M. pneumoniae-infected mice.

Role of SIRT-1 Gene in The Development of Diabetic Retinopathy

Background: Diabetes mellitus (DM) has had a consistent increase in global prevalence. A common microvascular disease associated with diabetes is diabetic retinopathy (DR). As a complex, progressive, as well as asymptomatic neurovascular consequence of DM, DR is the leading cause of vision impairment and blindness in working-age people. The presence of retinal neovascularization classifies diabetic retinopathy (DR) as proliferative, non-proliferative, or diabetic macular edema. Aim of the Study: to evaluate the level of expression of mRNA sirt1- gene in cases of type 2 DM that have retinopathy or vulnerable to it. Patients and Methods: In this research, 60 cases (15 patients with diabetic retinopathy, 15 diabetic cases without retinopathy (PDR), and 30 non-diabetic controls) were recruited. SIRT1 mRNA expression from the two groups was analyzed. Notably, patients with DR exhibited a decrease in the expression of SIRT1 mRNA. ELISA was also used to measure the levels of IL-17 expression in the serum. The results showed that the sera of people with DR had higher levels of IL-17 expression than the sera of healthy people. Results: The findings of this research indicate that imbalanced IL-17 & SIRT1 expression levels may play a role in the etiology of DR, with SIRT1 potentially exerting a protective effect by suppressing IL-17 production.

Dual Inhibition of Phosphodiesterase 3 and 4 Enzymes by Ensifentrine Protects against MRSA-Induced Lung Endothelial and Epithelial Dysfunction

Acute Respiratory Distress Syndrome (ARDS) is a severe lung condition with a high mortality rate for which there are no effective therapeutics. The failure of the alveolar–capillary barrier, composed of lung endothelial (EC) and alveolar epithelial (AEC) cells, is a critical factor leading to excessive inflammation and edema characteristic of acute lung injury (ALI) pathophysiology. Phosphodiesterases (PDE) are enzymes well-recognized for their roles in regulating endothelial permeability and inflammation. Although PDE inhibitors are used as therapeutics for inflammatory diseases like COPD (chronic obstructive pulmonary disease), their efficacy in treating ARDS has not yet been established. In this study, we investigated the effects of ensifentrine, an FDA-approved novel dual PDE 3/4 inhibitor, on lung endothelial and epithelial dysfunction caused by methicillin-resistant S. aureus (MRSA), a pathogen involved in bacterial ARDS. Human primary lung endothelial cells and alveolar epithelial cell lines (A549 and immortalized AEC) were treated with heat-killed MRSA, and their responses were assessed in the presence or absence of ensifentrine. Ensifentrine given either pre- or post-exposure attenuated MRSA-induced increased lung endothelial permeability. VE-cadherin junctions, which serve to stabilize the EC barrier, were disrupted by MRSA; however, ensifentrine effectively prevented this disruption. Pre-treatment with ensifentrine protected against MRSA-induced EC pro-inflammatory signaling by inhibiting the expression of VCAM-1, ICAM-1, and by reducing the IL-6 and IL-8 release. In AEC, MRSA caused the upregulation of ICAM-1, the activation of NF-kB, and the production of IL-8, all of which were inhibited by ensifentrine. These results indicate that the dual inhibition of phosphodiesterases 3 and 4 by ensifentrine is barrier protective and attenuates MRSA-induced inflammation in both lung endothelial and epithelial cells. The PDE3/4 inhibitor ensifentrine may represent a promising novel strategy for the treatment of MRSA-induced ARDS.

Gestational Diabetes Mellitus-Induced Inflammation in the Placenta via IL-1β and Toll-like Receptor Pathways

Gestational diabetes mellitus is characterised by an insufficient insulin response to hyperglycaemia and the development of insulin resistance. This state has adverse effects on the health outcomes of the mother and child. Existing hyperglycaemia triggers a state of inflammation that involves several tissues, including the placenta. In this study, we analysed the putative pathomechanism of GDM, with special emphasis on the role of chronic, sterile, pro-inflammatory pathways. The expression and regulation of the elements of IL-1β and Toll-like receptor (TLR) pathways in GDM maternal blood plasma, healthy placental explants and a choriocarcinoma cell line (BeWo cell line) stimulated with pro-inflammatory factors was evaluated. Our results indicate elevated expression of the IL-1β and TLR pathways in GDM patients. After stimulation with IL-1β or LPS, the placental explants and BeWo cell line showed increased production of pro-inflammatory IL-6, TNFa and IL-1β together with increased expression of the elements of the signalling pathways. The application of selected inhibitors of NF-ĸB, MAPK and recombinant interleukin 1 receptor antagonist (IL1RA) proved the key involvement of the IL-1β pathway and TLRs in the pathogenesis of GDM. Our results show the possible existence of loops of autocrine stimulation and a possible inflammatory pathomechanism in placentas affected by GDM.

Comparison οf Immune Responses Through Multiparametric T-Cell Cytokine Expression Profile Between Children with Convalescent COVID-19 or Multisystem Inflammatory Syndrome

Background/objectives: The immunological pathways that cause Multisystem Inflammatory Syndrome after SARS-CoV-2 infection in children (MIS-C) remain under investigation. Methods: The aim of this study was to prospectively compare the T-cell cytokine expression profile in unvaccinated children with acute MIS-C (MISC_A) before immunosuppression, convalescent MIS-C (one month after syndrome onset, MISC_C), convalescent COVID-19 (one month after hospitalization), and in healthy, unvaccinated controls. The intracellular expression of IL-4, IL-2, IL-17, IFNγ, TNF-α and Granzyme B, and the post SARS-CoV-2-Spike antigenic mix stimulation of T-cell subsets was analyzed by 13-color flow cytometry. Results: Twenty children with a median age (IQR) of 11.5 (7.25–14) years were included in the study. From the comparison of the flow cytometry analysis of the 14 markers of MISC_A with the other three groups (MISC_C, post-COVID-19 and controls), significant differences were identified as follows: 1. CD4+IL-17+/million CD3+: 293.0(256.4–870.9) vs. 50.7(8.4–140.5); p-value: 0.03, vs. 96.7(89.2–135.4); p-value: 0.03 and vs. 8.7(0.0–82.4); p-value: 0.03, respectively; 2. CD8+IL-17+/million CD3+: 335.2(225.8–429.9) vs. 78.0(31.9–128.9) vs. 84.1(0.0–204.6) vs. 33.2(0.0–114.6); p-value: 0.05, respectively; 3. CD8+IFNγ+/million CD3+: 162.2(91.6–273.4) vs. 41.5(0.0–77.4); p-value: 0.03 vs. 30.3(0.0–92.8); p-value: 0.08, respectively. Conclusions: In children presenting with MIS-C one month after COVID-19 infection, T cells were found to be polarized towards IL-17 and IFNγ production compared to those with uncomplicated convalescent COVID-19, a finding that could provide possible immunological biomarkers for MIS-C detection.

T lymphocyte-dependent IL-10 down-regulates a cytokine storm driven by Toxoplasma gondii GRA24.

As a model organism in the study of immunity to infection, Toxoplasma gondii has been instrumental in establishing key principles of host anti-microbial defense and its regulation. Here, we employed an attenuated uracil auxotroph strain of Type I Toxoplasma designated OMP to further untangle the early immune response to this parasitic pathogen. Experiments using αβ T cell-deficient Tcrb-/- mice unexpectedly revealed that an intact αβ T lymphocyte compartment was essential to survive infection with OMP. Subsequent antibody depletion and knockout mouse experiments demonstrated contributions from CD4+ T cells and most predominantly CD8+ T cells in resistance. Using transgenic knockout mice, we found only a partial requirement for IFN-γ and a lack of requirement for Toll-like receptor (TLR) adaptor MyD88 in resistance. In contrast to other studies on Toxoplasma, the ability to survive OMP infection did not require IL-12p40. Surprisingly, T cell-dependent IL-10 was found to be critical for survival, and deficiency of this cytokine triggered an abnormally high systemic inflammatory response. We also found that parasite molecule GRA24, a dense granule protein that triggers TLR-independent IL-12 production, acts as a virulence factor contributing to death of OMP-infected Tcrb-/- and IL-10-/- mice. Furthermore, resistance against OMP was restored in Tcrb-/- mice via monoclonal depletion of IL-12p40, suggesting that GRA24-induced IL-12 underlies the fatal immunopathology observed. Collectively, our studies provide insight into a novel and rapidly arising T lymphocyte-dependent anti-inflammatory response to T. gondii which operates independently of MyD88 and IL-12 and that depends on the function of parasite-dense granule protein GRA24.IMPORTANCEAs a model infectious microbe and an important human pathogen, the apicomplexan Toxoplasma gondii has provided many important insights into innate and adaptive immunity to infection. We show here that a low virulence uracil auxotrophic Toxoplasma strain emerges as a virulent parasite in the absence of an intact T cell compartment. Both CD4+ and CD8+ T lymphocytes are required for optimal protection, in line with previous findings in other models of Toxoplasma infection. Nevertheless, several novel aspects of the response were identified in our study. Protection occurs independently of IL-12 and MyD88 and only partially requires IFN-γ. This is noteworthy particularly because the cytokines IL-12 and IFN-γ have previously been regarded as essential for protective immunity to T. gondii. Instead, we identified the anti-inflammatory effects of T cell-dependent IL-10 as the critical factor enabling host survival. The parasite dense granule protein GRA24, a host-directed mitogen-activated protein kinase activator, was identified as a major virulence factor in T cell-deficient hosts. Collectively, our results provide new and unexpected insights into host resistance to Toxoplasma.

Enhanced immunomodulatory properties of ovalbumin through transglutaminase and tyrosinase/caffeic acid-catalyzed crosslinking plus galactomannan conjugation alleviates allergic asthma

Ovalbumin (OVA) is the primary allergenic protein, associated with T helper 2 (Th2)-mediated allergy reactions. Here, we studied OVA’s conformational structure, digestibility, and allergenic potency upon galactomannan (Man) conjugation along with transglutaminase-catalyzed crosslinking (TG-Man/OVA) and tyrosinase/caffeic acid-catalyzed crosslinking (Tyr-Man/OVA). Enzymatic glycosylation altered OVA’s conformation and enhanced the gastrointestinal digestibility. Stimulation of bone marrow-derived dendritic cells (BMDCs) with enzymatically glycosylated OVA reduced the expression of CD40, CD80, CD86 and MHC class II molecules. Furthermore, glycosylated OVA increased IL-10 production while suppressing proinflammatory cytokine production in BMDCs. In an OVA-induced mouse asthma model, TG-Man/OVA and Tyr-Man/OVA upregulated IFN-γ and IL-10 expression and downregulated IL-4, IL-5, and IL-13 in lungs. Crosslinked OVA diminished infiltrated cells in bronchoalveolar lavage fluid and lung and attenuated eosinophilic airway inflammation. These findings offer valuable insights into the development of a novel product with improved hypoallergenic and immunomodulatory properties and hold promise in attenuating allergic diseases.

Long-term enzyme replacement therapy in Fabry patients protects against oxidative and inflammatory process.

Fabry disease (FD) is an X-linked recessive lysosomal storage disorder, characterized by a deficiency of α-galactosidase, which causes the progressive accumulation of glycosphingolipids, especially globotriaosylsphingosine (Gb3), in lysosomes across multiple organs. Substrate deposition, associated with tissue damage in FD, also contributes to the emergence of a pro-inflammatory state presented by some patients. We investigated pro- and anti-inflammatory cytokines, and the expression of inflammation-associated genes in treated FD patients, as well as oxidative parameters. We found a decrease in the production of cytokines IL-1β, IL-6, IL-10, and TNF-α in male FD patients and a normalization of redox status in male and female FD patients, once the levels of protein, lipid oxidation, and nitrite and nitrate content were like healthy individuals. Our results suggest that long-term ERT in men with FD contributes to the reduction of a pro-inflammatory scenario and a decrease of oxidative damage in patients, reflecting greater control throughout the disease and in the multisystemic changes characteristic of this disorder. These findings lead us to believe that long-term ERT can improve the redox status and protect these individuals against oxidative and nitrative stress, as well as the inflammatory process.

Basophils Induce Pro-Tumorigenic Cytokines from A549 Lung Adenocarcinoma via Mechanisms Requiring IgE, Galectin-3, and IL-3 Priming.

Galectin-3 (Gal-3) is implicated in innate immune cell activation in a host of diseases/conditions. We identified a unique response whereby human basophils secrete IL-4/IL-13 when co-cultured with A549 cells -a lung adenocarcinoma. While displaying parameters consistent with standard IgE-dependent activation, these Galectin-3-dependent responses occurred in the absence of specific IgE/allergen and required cell-to-cell contact. We now hypothesize that this mode of activation also impacts A549 function. Our findings show that cytokines are induced in basophil/A549 co-cultures that are not detected when either cell is cultured alone, in particular IL-6. As previously shown for IL-4/IL-13, IL-6 production also required cell-to-cell contact and was dependent on A549-Gal-3, since clones deficient of this lectin induced less cytokine. Using culture-derived basophils (CDBA), we demonstrate that the IL-6 response, and production of another tumorigenic factor, VEGF-A, are induced in CDBA/A549 co-cultures but only after passively sensitizing CDBA with IgE, in a manner similar to IL-4/IL-13. However, IgE-dependent activation of basophils/CDBA cultured alone failed to induce IL-6/VEGF. Importantly, IL-3-primed basophils, even those fixed with paraformaldehyde, readily induced IL-6/VEGF-A in co-cultures, thus verifying these cytokines are derived from A549. Overall, these results suggest a complex mechanism whereby Gal-3/IgE interactions between IL-3-primed basophils and A549 have the potential to modulate cytokine production by both cells. With Gal-3 implicated in many diseases ranging from asthma to cancer, but also in normal physiological conditions, such as wound healing, these findings are predicted to provide insight into the molecular mechanisms by which this lectin (and IgE) functions in these processes.

Total synthesis, stereochemical assignment, and biological evaluation of opantimycin A and analogues thereof.

Opantimycin A, a rare antimycin-class antibiotic without the macrolide core, was isolated from Streptomyces sp. RK88-1355 in 2017. In this study, we explored the total synthesis and stereochemical assignment of opantimycin A. The synthesis of all potential diastereomers has been accomplished via traceless Staudinger ligation. A comparison of the spectroscopic data of the synthesized compounds with that reported for the natural product confirmed that the absolute configuration of the natural product was (14S,17R,21R). Two analogous compounds were prepared, where the Dhb ((Z)-dehydrobutyrine) moiety was replaced with Dha (dehydroalanine) or ΔVal moieties, respectively. The inhibitory activities of these synthetic compounds against the production of the anti-inflammatory cytokine IL-6 were evaluated, and two potential candidates for further development as anti-inflammatory agents were identified.