Pro-inflammatory Stimulation Research Articles

Siponimod Modulates the Reaction of Microglial Cells to Pro-Inflammatory Stimulation

Siponimod (Mayzent®), a sphingosine 1-phosphate receptor (S1PR) modulator which prevents lymphocyte egress from lymphoid tissues, is approved for the treatment of relapsing-remitting and active secondary progressive multiple sclerosis. It can cross the blood-brain barrier (BBB) and selectively binds to S1PR1 and S1PR5 expressed by several cell populations of the central nervous system (CNS) including microglia. In multiple sclerosis, microglia are a key CNS cell population moving back and forth in a continuum of beneficial and deleterious states. On the one hand, they can contribute to neurorepair by clearing myelin debris, which is a prerequisite for remyelination and neuroprotection. On the other hand, they also participate in autoimmune inflammation and axonal degeneration by producing pro-inflammatory cytokines and molecules. In this study, we demonstrate that siponimod can modulate the microglial reaction to lipopolysaccharide-induced pro-inflammatory activation.

What's New in Musculoskeletal Basic Science.

What's New in Musculoskeletal Basic Science.

SARS-CoV-2 Variants Show a Gradual Declining Pathogenicity and Pro-Inflammatory Cytokine Stimulation, an Increasing Antigenic and Anti-Inflammatory Cytokine Induction, and Rising Structural Protein Instability: A Minimal Number Genome-Based Approach.

Hyper-transmissibility with decreased disease severity is a typical characteristic of the SARS-CoV-2 Omicron variant. To understand this phenomenon, we used various bioinformatics approaches to analyze randomly selected genome sequences (one each) of the Gamma, Delta, and Omicron variants submitted to NCBI from December 15 to 31, 2021. We report that the pathogenicity of SARS-CoV-2 variants decreases in the order of Wuhan > Gamma > Delta > Omicron; however, the antigenic property follows the order of Omicron > Gamma > Wuhan > Delta. The Omicron spike RBD shows lower pathogenicity but higher antigenicity than other variants. The reported decreased disease severity by the Omicron variant may be due to its decreased pro-inflammatory and IL-6 stimulation and increased IFN-γ and IL-4 induction efficacy. The mutations in the N protein are probably associated with this decreased IL-6 induction and human DDX21-mediated increased IL-4 production for Omicron. Due to the mutations, the stability of S, M, N, and E proteins decreases in the order of Omicron > Gamma > Delta > Wuhan. Although a stronger spike RBD-hACE2 binding of Omicron increases its transmissibility, the lowest stability of its spike protein makes spike RBD-hACE2 interaction weak for systemic infection and for causing severe disease. Finally, the highest instability of the Omicron E protein may also be associated with decreased viral maturation and low viral load, leading to less severe disease and faster recovery. Our findings will contribute to the understanding of the dynamics of SARS-CoV-2 variants and the management of emerging variants. This minimal genome-based method may be used for other similar viruses avoiding robust analysis.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10753-022-01734-w.

Inflammation-Driven Secretion Potential Is Upregulated in Osteoarthritic Fibroblast-Like Synoviocytes.

Osteoarthritis (OA) is one of the most common joint pathologies and a major cause of disability among the population of developed countries. It manifests as a gradual degeneration of the cartilage and subchondral part of the bone, leading to joint damage. Recent studies indicate that not only the cells that make up the articular cartilage but also the synoviocytes, which build the membrane surrounding the joint, contribute to the development of OA. Therefore, the aim of the study was to determine the response to inflammatory factors of osteoarthritic synoviocytes and to identify proteins secreted by them that may influence the progression of OA. This study demonstrated that fibroblast-like synoviocytes of OA patients (FLS-OA) respond more strongly to pro-inflammatory stimulation than cells obtained from control patients (FLS). These changes were observed at the transcriptome level and subsequently confirmed by protein analysis. FLS-OA stimulated by pro-inflammatory factors [such as lipopolysaccharide (LPS) and tumor necrosis factor alpha (TNFα) were shown to secrete significantly more chemokines (CXCL6, CXCL10, and CXCL16) and growth factors [angiopoietin-like protein 1 (ANGPTL1), fibroblast growth factor 5 (FGF5), and insulin-like growth factor 2 (IGF2)] than control cells. Moreover, the translation of proteolytic enzymes [matrix metalloprotease 3 (MMP3), cathepsin K (CTSK), and cathepsin S (CTSS)] by FLS-OA is increased under inflammatory conditions. Our data indicate that the FLS of OA patients are functionally altered, resulting in an enhanced response to the presence of pro-inflammatory factors in the environment, manifested by the increased production of the previously mentioned proteins, which may promote further disease progression.

A tendency to worse course of multisystem inflammatory syndrome in children with obesity: MultiOrgan Inflammatory Syndromes COVID-19 related study.

BackgroundA new disease entity called multisystem inflammatory syndrome in children (MIS-C) is a rare consequence of COVID-19 infection. The pathophysiology and risk factors of MIS-C are still unclear, and the clinical manifestation ranges from milder forms to cases needing intensive care unit treatment. Based on available data, obesity is linked to pro-inflammatory stimulation. Moreover, several studies showed that obesity could play a role in COVID-19 severity and its comorbidities among the adult and children’s populations. This study aimed to investigate the influence of overweightedness/obesity in childhood for the course of MIS-C in Poland.MethodsThis study presented data from the national MultiOrgan Inflammatory Syndromes COVID-19 Related Study (MOIS-CoR) collected between 4 March 2020 and 20 February 2021. Of the 371 patients that met the Polish MIS-C criteria, 306 were included for further analysis.ResultsChildren who are obese (OB with body mass index (BMI) ≥95th percentile) and overweight (OV with BMI ≥85th percentile but <95th percentile) (28 and 49 patients, respectively) represented 25.1% (n=77) of all recruited patients. Complete recovery at the time of discharge presented in 93% of normal body weight (NW) participants and 90% of OV children (p>0.05). Among OB children, 76% recovered fully, which differed from the NW group (p=0.01). Calculated odds ratio (OR) of incomplete recovery for OB children was 4.2. Irrespective of body weight, there were no differences (p>0.05) in the length of hospitalization and the duration of symptoms (for OB, 13 and 16.5 days; for OV and NW, 10 and 14 days, respectively), as well as in the frequency of cardiovascular abnormalities, necessity of oxygen therapy (OB, 26.9%; OV, 23.9%; and NW, 20.7%), and intravenous immunoglobulin and glucocorticosteroid (GCS) treatment.ConclusionThe higher risk of incomplete recovery and observed tendency toward a worsening course of MIS-C in patients with obesity suggest the need for further studies to confirm and understand our findings.

Interleukin 38 alleviates aortic valve calcification by inhibition of NLRP3.

Calcific aortic valve disease (CAVD) is common in people over the age of 65. Progressive valvular calcification is a characteristic of CAVD and due to chronic inflammation in aortic valve interstitial cells (AVICs) resulting in CAVD progression. IL-38 is a naturally occurring anti-inflammatory cytokine; here, we report lower levels of endogenous IL-38 in AVICs isolated from patients' CAVD valves compared to AVICs from non-CAVD valves. Recombinant IL-38 suppressed spontaneous inflammatory activity and calcium deposition in cultured AVICs. In mice, knockdown of IL-38 enhanced the production of inflammatory mediators in murine AVICs exposed to the proinflammatory stimulant matrilin-2. We also observed that in cultured AVICs matrilin-2 stimulation activated the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome with procaspase-1 cleavage into active caspase-1. The addition of IL-38 to matrilin-2-treated AVICs suppressed caspase-1 activation and reduced the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, runt-related transcription factor 2, and alkaline phosphatase. Aged IL-38-deficient mice fed a high-fat diet exhibited aortic valve lesions compared to aged wild-type mice fed the same diet. The interleukin-1 receptor 9 (IL-1R9) is the putative receptor mediating the anti-inflammatory properties of IL-38; we observed that IL-1R9-deficient mice exhibited spontaneous aortic valve thickening and greater calcium deposition in AVICs compared to wild-type mice. These data demonstrate that IL-38 suppresses spontaneous and stimulated osteogenic activity in aortic valve via inhibition of the NLRP3 inflammasome and caspase-1. The findings of this study suggest that IL-38 has therapeutic potential for prevention of CAVD progression.

P8. Responsiveness of patient derived intervertebral disc cells to mechanobiological treatment

P8. Responsiveness of patient derived intervertebral disc cells to mechanobiological treatment

Human repair-related Schwann cells adopt functions of antigen-presenting cells in vitro.

The plastic potential of Schwann cells (SCs) is increasingly recognized to play a role after nerve injury and in diseases of the peripheral nervous system. Reports on the interaction between immune cells and SCs indicate their involvement in inflammatory processes. However, the immunocompetence of human SCs has been primarily deduced from neuropathies, but whether after nerve injury SCs directly regulate an adaptive immune response is unknown. Here, we performed comprehensive analysis of immunomodulatory capacities of human repair-related SCs (hrSCs), which recapitulate SC response to nerve injury in vitro. We used our well-established culture model of primary hrSCs from human peripheral nerves and analyzed the transcriptome, secretome, and cell surface proteins for pathways and markers relevant in innate and adaptive immunity, performed phagocytosis assays, and monitored T-cell subset activation in allogeneic co-cultures. Our findings show that hrSCs are phagocytic, which is in line with high MHCII expression. Furthermore, hrSCs express co-regulatory proteins, such as CD40, CD80, B7H3, CD58, CD86, and HVEM, release a plethora of chemoattractants, matrix remodeling proteins and pro- as well as anti-inflammatory cytokines, and upregulate the T-cell inhibiting PD-L1 molecule upon pro-inflammatory stimulation with IFNγ. In contrast to monocytes, hrSC alone are not sufficient to trigger allogenic CD4+ and CD8+ T-cells, but limit number and activation status of exogenously activated T-cells. This study demonstrates that hrSCs possess features and functions typical for professional antigen-presenting cells in vitro, and suggest a new role of these cells as negative regulators of T-cell immunity during nerve regeneration.

Quantitative profiling of differentially expressed oxylipins in ADSCs under proinflammatory cytokine stimulation.

Mesenchymal stem cells (MSCs) have been proved to have anti-inflammatory capabilities, but the mechanisms are still under investigation. Recently, oxylipins have been identified as being related to the immuno-regulation function of MSCs, but the MSC-derived oxylipins, especially under the stimulation of versatile pro-inflammatory cytokines, have never been comprehensively analyzed. In the present research, a UPLC-MS/MS method was employed to identify and quantify the oxylipin profiles of adipose-derived mesenchymal stem cells (ADSCs) under cytokine stimulation (IL-1β, TNF-α, IFN-𝛾 and TNF-α + IFN-𝛾). The differentially produced oxylipins between experimental groups were analyzed and compared. The elevated level of lipoxygenase-15 (LOX-15) mRNA was further verified by qRT-PCR analysis. From the targeted 71 oxylipins, we detected and quantified 57 oxylipins, while 14 were not detected. Distinctive from other cytokines, ADSCs activated by the combination of IFN-𝛾 and TNF-α up-regulated LOX-15 products 7-HDHA and 15-HEPE, which were metabolized from docosahexaenoic acid (DHA) and eicosapentaenoic acid, respectively, and involved in the pro-resolution phase of inflammation. The results reported here make a first step towards a comprehensive characterization of MSC-derived oxylipins under differential proinflammatory cytokine stimulation. The findings may lay a fundamental foundation for MSC-based therapies and further determine ways to optimize the therapeutic potential of MSCs.

The Role of Mitochondrial Mutations in Chronification of Inflammation: Hypothesis and Overview of Own Data.

Chronic human diseases, especially age-related disorders, are often associated with chronic inflammation. It is currently not entirely clear what factors are responsible for the sterile inflammatory process becoming chronic in affected tissues. This process implies impairment of the normal resolution of the inflammatory response, when pro-inflammatory cytokine production ceases and tissue repair process begins. The important role of the mitochondria in the correct functioning of innate immune cells is currently well recognized, with mitochondrial signals being an important component of the inflammatory response regulation. In this work, we propose a hypothesis according to which mitochondrial DNA (mtDNA) mutations may play a key role in rendering certain cells prone to prolonged pro-inflammatory activation, therefore contributing to chronification of inflammation. The affected cells become sites of constant pro-inflammatory stimulation. The study of the distribution of atherosclerotic lesions on the surface of the arterial wall samples obtained from deceased patients revealed a focal distribution of lesions corresponding to the distribution of cells with altered morphology that are affected by mtDNA mutations. These observations support the proposed hypothesis and encourage further studies.

Pharmacologic modulation of intracellular Na+ concentration with ranolazine impacts inflammatory response in humans and mice

Changes in Ca2+ influx during proinflammatory stimulation modulates cellular responses, including the subsequent activation of inflammation. Whereas the involvement of Ca2+ has been widely acknowledged, little is known about the role of Na+. Ranolazine, a piperazine derivative and established antianginal drug, is known to reduce intracellular Na+ as well as Ca2+ levels. In stable coronary artery disease patients (n = 51) we observed reduced levels of high-sensitive C-reactive protein (CRP) 3 mo after the start of ranolazine treatment (n = 25) as compared to the control group. Furthermore, we found that in 3,808 acute coronary syndrome patients of the MERLIN-TIMI 36 trial, individuals treated with ranolazine (1,934 patients) showed reduced CRP values compared to placebo-treated patients. The antiinflammatory effects of sodium modulation were further confirmed in an atherosclerotic mouse model. LDL-/- mice on a high-fat diet were treated with ranolazine, resulting in a reduced atherosclerotic plaque burden, increased plaque stability, and reduced activation of the immune system. Pharmacological Na+ inhibition by ranolazine led to reduced express of adhesion molecules and proinflammatory cytokines and reduced adhesion of leukocytes to activated endothelium both invitro and invivo. We demonstrate that functional Na+ shuttling is required for a full cellular response to inflammation and that inhibition of Na+ influx results in an attenuated inflammatory reaction. In conclusion, we demonstrate that inhibition of Na+-Ca2+ exchange during inflammation reduces the inflammatory response in human endothelial cells invitro, in a mouse atherosclerotic disease model, and in human patients.

Insights into IL-33 on inflammatory response during in vitro infection by Trypanosoma cruzi

Inflammatory and regulatory cytokines play an important role in the immunopathogenesis of Trypanosoma cruzi infection. Interleukin (IL)-33 is a member of the IL-1 superfamily of cytokines whose expression/production is upregulated following pro-inflammatory stimulation to alert the immune system in response to tissue stress or damage. The aim of this study was to evaluate the inflammatory profile induced in cultured J774 cells stimulated or not with IL-33 (10 ng/mL), with live parasites (1 × 106 metacyclic trypomastigote forms) and/or total antigen, TcAg (100 µg/mL) and with both, IL-33 and TcAg/T. cruzi. The cultures were evaluated at 24 h and 48 h after addition of the stimuli. For this, the supernatants were collected for the measurement of TNF, IL-17, CCL2, and IL-10 by ELISA and of nitrite by the Griess method. TNF, IL-17, and CCL2 concentrations were elevated in the presence of TcAg or live T. cruzi parasites at 24 h, and the addition of IL-33 potentiated these effects at 48 h. In addition, the T. cruzi-amastigote forms reduced in those infected J774 cells stimulated with IL-33 at 48 h. In conclusion, the IL-33 elevated the production of the TNF, IL-17, and CCL2 in cultured J774 cells stimulated with T. cruzi and/or its antigen and reduced the intracellular parasites, providing impetus to new investigations on its potential actions on the parasite-induced inflammation.

Managing SARS-CoV2 Infections Through Resolution of Inflammation by Eicosanoids: A Review.

Severe Corona Virus Disease is characterized by angiocentric inflammation of lungs and cytokine storm leading to potentially fatal multiple organ failure. Several studies have shown the high levels of pro-inflammatory cytokines, indicative of a poor prognosis in COVID-19. Eicosanoids play an important role in the induction of inflammation and cytokine production, while anti-inflammatory and pro-resolving properties of some eicosanoic acid derivatives enable inflamed tissues to return to homeostasis through the resolution of inflammation by aiding the clearance of cell debris and downregulation of pro-inflammatory stimulants. This review attempts to provide an overall insight on the eicosanoids synthesis and their role in the resolution of inflammation in the context of Corona Virus infection.

Antibiotic perturbation of gut bacteria does not significantly alter host responses to ocular disease in a songbird species.

Bacterial communities in and on wild hosts are increasingly appreciated for their importance in host health. Through both direct and indirect interactions, bacteria lining vertebrate gut mucosa provide hosts protection against infectious pathogens, sometimes even in distal body regions through immune regulation. In house finches (Haemorhous mexicanus), the bacterial pathogen Mycoplasma gallisepticum (MG) causes conjunctivitis, with ocular inflammation mediated by pro- and anti-inflammatory cytokines and infection triggering MG-specific antibodies. Here, we tested the role of gut bacteria in host responses to MG by using oral antibiotics to perturb bacteria in the gut of captive house finches prior to experimental inoculation with MG. We found no clear support for an impact of gut bacterial disruption on conjunctival pathology, MG load, or plasma antibody levels. However, there was a non-significant trend for birds with intact gut communities to have greater conjunctival pathology, suggesting a possible impact of gut bacteria on pro-inflammatory cytokine stimulation. Using 16S bacterial rRNA amplicon sequencing, we found dramatic differences in cloacal bacterial community composition between captive, wild-caught house finches in our experiment and free-living finches from the same population, with lower bacterial richness and core communities composed of fewer genera in captive finches. We hypothesize that captivity may have affected the strength of results in this experiment, necessitating further study with this consideration. The abundance of anthropogenic impacts on wildlife and their bacterial communities, alongside the emergence and spread of infectious diseases, highlights the importance of studies addressing the role of commensal bacteria in health and disease, and the consequences of gut bacterial shifts on wild hosts.

Divergence of acetate uptake in proinflammatory and inflammation-resolving macrophages: implications for imaging atherosclerosis

BackgroundMetabolic divergence of macrophages polarized into different phenotypes represents a mechanistically relevant target for non-invasive characterization of atherosclerotic plaques using positron emission tomography (PET). Carbon-11 (11C)-labeled acetate is a clinically available tracer which accumulates in atherosclerotic plaques, but its biological and clinical correlates in atherosclerosis are undefined. Methods and resultsHistological correlates of 14C-acetate uptake were determined in brachiocephalic arteries of western diet-fed apoE−/− mice. The effect of polarizing stimuli on 14C-acetate uptake was determined by proinflammatory (interferon-γ + lipopolysaccharide) vs inflammation-resolving (interleukin-4) stimulation of murine macrophages and human carotid endarterectomy specimens over 2 days. 14C-acetate accumulated in atherosclerotic regions of arteries. CD68-positive monocytes/macrophages vs smooth muscle actin-positive smooth muscle cells were the dominant cells in regions with high vs low 14C-acetate uptake. 14C-acetate uptake progressively decreased in proinflammatory macrophages to 25.9 ± 4.5% of baseline (P < .001). A delayed increase in 14C-acetate uptake was induced in inflammation-resolving macrophages, reaching to 164.1 ± 21.4% (P < .01) of baseline. Consistently, stimulation of endarterectomy specimens with interferon-γ + lipopolysaccharide decreased 14C-acetate uptake to 66.5 ± 14.5%, while interleukin-4 increased 14C-acetate uptake to 151.5 ± 25.8% compared to non-stimulated plaques (P < .05). ConclusionsAcetate uptake by macrophages diverges upon proinflammatory and inflammation-resolving stimulation, which may be exploited for immunometabolic characterization of atherosclerosis.

Procalcitonin as new inflammatory mediator in cases of 1st episode drug naive major depressive disorder: a case-control study

IntroductionProcalcitonin (PCT) is the prohormone of calcitonin.Whereas calcitonin is only produced in the C cells of thethyroid gland as a result of hormonal stimulus, PCT is secreted by different cells from numerous organs in response to proinflammatory stimulation, particularly bacterial overactivity,also procalcitonin level might be elevated during the depressive episode as a result of inflammatory theory.PCT assessment is not fully studied in different psychaiatric disorders and particularly in major depressive disorder.Objectives1-To study the level of Procalcitonin level in 1st episode drug naive major depressive disorder. 2-To investigate the relation between procalcitonin level and cognitive dysfunctions in these patients 3-To illustrate the role of PCT in psychopathology of Major depressive disorderMethods1-Socio-demographic data of the target group of patients 2-Psychiatric evaluation using DSM 5 diagnostic criteria 3-Hamilton rating scale of Depression 4-Laboratory assessment of Procalcitonin level (PCT) using VIDAS® B·R·A·H·M·S PCT™ 5-Cogintive evaluation using novel battery of THINC-ITResults1-Elevated level of Procalcitonin(PCT) in the targeted patients in comparison to control group 2-The level of PCT is positively associated with the cognitive dysfuctions reported in these patients. 3-The severity of depressive psychopathology is related positively to the elevated level of PCTConclusionsProcalcitonin (PCT) assessment played an importnat role in the etiopathogenesis of 1st episode drug naive major depressive disorder,also it has a crucial role in the cognitive dysfunctions commonly reported in these patientsDisclosureNo significant relationships.

Polyphenols and Maillard Reaction Products in Dried Prunus spinosa Fruits: Quality Aspects and Contribution to Anti-Inflammatory and Antioxidant Activity in Human Immune Cells Ex Vivo.

Dried Prunus spinosa fruits (sloes) are folk phytotherapeutics applied to treat chronic inflammatory disorders. However, their pharmacological potential, activity vectors, and drying-related changes in bioactive components remain unexplored. Therefore, the present research aimed to evaluate the anti-inflammatory and antioxidant effects of dried sloes in ex vivo models of human neutrophils and peripheral blood mononuclear cells (PMBCs) and establish their main active components. It was revealed that the fruit extracts significantly and dose-dependently inhibited the respiratory burst, downregulated the production of elastase (ELA-2) and TNF-α, and upregulated the IL-10 secretion by immune cells under pro-inflammatory and pro-oxidant stimulation. The slightly reduced IL-6 and IL-8 secretion was also observed. The structural identification of active compounds, including 45 phenolics and three Maillard reaction products (MRPs) which were formed during drying, was performed by an integrated approach combining LC-MS/MS, preparative HPLC isolation, and NMR studies. The cellular tests of four isolated model compounds (chlorogenic acid, quercetin, procyanidin B2, and 5-hydroxymethylfurfural), supported by statistical correlation studies, revealed a significant polyphenolic contribution and a slight impact of MRPs on the extracts’ effects. Moreover, a substantial synergy was observed for phenolic acids, flavonoids, condensed proanthocyanidins, and MPRs. These results might support the phytotherapeutic use of dried P. spinosa fruits to relieve inflammation and establish the quality control procedure for the extracts prepared thereof.

The Hidden Side of Complement Regulator C4BP: Dissection and Evaluation of Its Immunomodulatory Activity.

C4b-binding protein (C4BP) is a well-known regulator of the complement system that holds additional and important activities unrelated to complement inhibition. Recently, we have described a novel immunomodulatory activity in the minor C4BP(β-) isoform directly acting over inflammatory phagocytes. Here we show that incorporation of the β-chain to the C4BP α-chain oligomer interferes with this immunomodulatory activity of C4BP. Moreover, an oligomeric form including only the complement control protein 6 (CCP6) domain of the C4BP α-chain (PRP6-HO7) is sufficient to “reprogram” monocyte-derived DCs (Mo-DCs) from a pro-inflammatory and immunogenic phenotype to an anti-inflammatory and tolerogenic state. PRP6-HO7 lacks complement regulatory activity but retains full immunomodulatory activity over inflammatory Mo-DCs induced by TLRs, characterized by downregulation of relevant surface markers such as CD83, HLA-DR, co-stimulatory molecules such as CD86, CD80 and CD40, and pro-inflammatory cytokines such as IL-12 and TNF-α. Furthermore, PRP6-HO7-treated Mo-DCs shows increased endocytosis, significantly reduced CCR7 expression and CCL21-mediated chemotaxis, and prevents T cell alloproliferation. Finally, PRP6-HO7 shows also full immunomodulatory activity over Mo-DCs isolated from lupus nephritis patients with active disease, even without further pro-inflammatory stimulation. Therefore PRP6-HO7, retaining the immunomodulatory activity of C4BP(β-) and lacking its complement regulatory activity, might represent a promising and novel alternative to treat autoimmune diseases.

RNA Microarray-Based Comparison of Innate Immune Phenotypes between Human THP-1 Macrophages Stimulated with Two BCG Strains.

Currently, the only available vaccine against tuberculosis is Mycobacterium bovis Bacille Calmette-Guérin (BCG). Pulmonary tuberculosis protection provided by the vaccine varies depending on the strain, the patient’s age and the evaluated population. Although the adaptive immune responses induced by different BCG strains have been widely studied, little conclusive data is available regarding innate immune responses, especially in macrophages. Here, we aimed to characterize the innate immune responses of human THP-1-derived macrophages at the transcriptional level following a challenge with either the BCG Mexico (M.BCG) or Phipps (P.BCG) strains. After a brief in vitro characterization of the bacterial strains and the innate immune responses, including nitric oxide production and cytokine profiles, we analyzed the mRNA expression patterns and performed pathway enrichment analysis using RNA microarrays. Our results showed that multiple biological processes were enriched, especially those associated with innate inflammatory and antimicrobial responses, including tumor necrosis factor (TNF)-α, type I interferon (IFN-I) and IFN-γ. However, four DEGs were identified in macrophages infected with M.BCG compared to P. BCG. These findings indicated the proinflammatory stimulation of macrophages induced by both BCG strains, at the cytokine level and in terms of gene expression, suggesting a differential expression pattern of innate immune transcripts depending on the mycobacterial strain.

Role of Tocilizumab in Down Regulating sCD163 Plasmatic Levels in a Cohort of COVID-19 Patients.

BackgroundCD163, a haptoglobin-hemoglobin scavenger receptor mostly expressed by monocytes and macrophages, is involved in the regulation of inflammatory processes. Following proteolytic cleavage after pro-inflammatory stimulation, CD163 is shed from the cell surface and its soluble form in plasma, sCD163, is a biomarker of monocyte/macrophage lineage activation.The assessment of sCD163 plasmatic levels in an early stage of the disease could have clinical utility in predicting the severity of COVID-19 pneumonia. The use of tocilizumab (monoclonal antibody anti-IL-6 receptor) in COVID-19 patients reduces lethality rate at 30 days. The aim of the study was to investigate the effect of tocilizumab on sCD163 plasmatic levels in a cohort of COVID-19 patients.MethodsIn COVID-19 patients, on hospital admission (T0), after 7 days from hospitalization (T7) and after 45 days from discharge (T45) sCD163 plasmatic levels were evaluated, along with other laboratory parameters. COVID-19 patients were stratified into tocilizumab (TCZ) and non-tocilizumab (non-TCZ) groups. TCZ group was further divided into responder (R) and non-responder (NR) groups. Patients who died or required mechanical ventilation were defined as NR. As control group, healthy donors (HD) were enrolled.ResultsSeventy COVID-19 patients and 47 HD were enrolled. At T0, sCD163 plasmatic levels were higher in COVID-19 patients compared to HD (p<0.0001) and the longitudinal evaluation showed a reduction in sCD163 plasmatic levels at T7 compared to T0 (p=0.0211). At T0, both TCZ and non-TCZ groups showed higher sCD163 plasmatic levels compared to HD (p<0.0001 and p=0.0147, respectively). At T7, the longitudinal evaluation showed a significant reduction in sCD163 plasmatic levels (p=0.0030) only in the TCZ group, reaching levels comparable to those of HD. Conversely, not statistically significance in non-TCZ group was observed and, at T7, a statistically significance was found comparing non-TCZ group to HD (p=0.0019). At T0, R and NR groups showed not statistically significance in sCD163 plasmatic levels and both groups showed higher levels compared to HD (p=0.0001 and p=0.0340, respectively). The longitudinal evaluation showed significant reductions in both groups (R: p=0.0356; NR: p=0.0273) independently of the outcome. After 45 days of follow-up sCD163 plasmatic levels remain stable.ConclusionsCD163 plasmatic levels are increased in COVID-19 pneumonia and is efficiently down-regulated by tocilizumab treatment regardless of the clinical outcome.