Monocyte Inflammatory Responses Research Articles

A loss of tuning of both pro-coagulant and inflammatory responses in monocytes in patients with preeclampsia

An imbalance between pro- and anti-angiogenesis is one of the leading causes of preeclampsia (PE). Monocytes, known as regulators of angiogenesis during immune responses, cooperate with platelets, but the specifics of these responses during pregnancy remain unclear. In this study, we investigated the relationship between pro-coagulant responses on monocytes [platelet activation marker CD61 as a monocyte-platelet aggregate (MPA), tissue factor (CD142), etc.], inflammatory responses [soluble CD40 ligand (sCD40L), soluble suppression of tumorigenesis-2 (sST2), etc.], and the balance of angiogenesis [soluble Fms-related receptor tyrosine kinase 1/placental growth factor (sFlt-1/PLGF) ratio]. In PE, markers of pro-coagulant and inflammatory responses were higher than those in normal pregnancy (NP). Interestingly, in NP, these markers harmonized with the sFlt-1/PLGF ratio, but not in PE. Furthermore, ex vivo examinations showed that upregulation of CD142 induced by additional platelet activation with adenosine diphosphate was diminished in PE. Conversely, low-dose aspirin, which is used as a preventive treatment for PE, could inhibit the increase of CD61 and sST2 under inflammatory stimuli and platelet activation in NP but not in PE. These results indicate that monocytes in PE upregulate basal activity and lose responsiveness to stimulation. The elevation of pro-coagulant and inflammatory responses may be mitigated by prophylaxis with low-dose aspirin. Therefore, the findings suggesting a loss of tuning of both pro-coagulant and inflammatory responses on monocytes help in understanding the pathology of PE. The harmonization between pro-coagulant responses, inflammatory responses, and angiogenesis may serve as useful indicators for the prediction and preventive treatment of PE.

Effect of statin administration on the inflammatory response of monocytes in patients with atherosclerosis

Currently, statins are the main preparations of anti-atherosclerotic therapy due to a number of effects that reduce the progression of atherosclerosis, including anti-inflammatory effectiveness. The purpose of this study was to evaluate the inflammatory response of monocytes in patients with severe atherosclerosis during therapy with hydrophilic and lipophilic statins, as well as in patients with atherosclerosis not receiving lipid-lowering therapy. A total of 60 patients with severe atherosclerosis of the coronary arteries were included in the study in three groups: 1) receiving atovastatin therapy for at least 12 months before inclusion in the study, n = 20; 2) receiving rosuvastatin therapy for at least 12 months before inclusion in the study, n = 20; and 3) those who had not received statin therapy within a year before inclusion in the study, n = 20. The primary culture of monocytes from study participants was obtained by gradient centrifugation followed by immunomagnetic separation of CD14+ monocytes. The isolated cells were cultured for 7 days without stimulation and with pro-inflammatory stimulation using lipopolysaccharide (LPS). The level of basal, LPS-stimulated and re-stimulated secretion of TNFα and IL-1β was determined by enzyme immunoassay. Basal secretion of TNFα and IL-1β in patients receiving statins was lower than in patients who did not receive statins for a year; the secretion of both cytokines was significantly lower in the rosuvastatin group. LPS-stimulated TNFα secretion was significantly lower in the groups of patients receiving statins; IL-1β secretion was significantly lower in the atorvastatin and rosuvastatin groups compared to the group without statins. Re-stimulated IL-1β secretion did not differ significantly between groups; re-stimulated TNFα secretion was significantly lower in the rosuvastatin group compared to the atorvastatin and non-statin groups. Thus, the results of the study demonstrate the anti-inflammatory effectiveness of rosuvastatin, expressed in a decrease in the secretion of pro-inflammatory cytokines by cultured monocytes/macrophages of patients with severe coronary atherosclerosis.

CEACAM1-engineered MSCs have a broad spectrum of immunomodulatory functions and therapeutic potential via cell-to-cell interaction

Mesenchymal stem cells (MSCs) have garnered attention for their regenerative and immunomodulatory capabilities in clinical trials for various diseases. However, the effectiveness of MSC-based therapies, especially for conditions like graft-versus-host disease (GvHD), remains uncertain. The cytokine interferon (IFN)-γ has been known to enhance the immunosuppressive properties of MSCs through cell-to-cell interactions and soluble factors. In this study, we observed that IFN-γ-treated MSCs upregulated the expression of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), associated with immune evasion through the inhibition of natural killer (NK) cell cytotoxicity. To co-opt this immunomodulatory function, we generated MSCs overexpressing CEACAM1 and found that CEACAM1-engineered MSCs significantly reduced NK cell activation and cytotoxicity via cell-to-cell interaction, independent of NKG2D ligand regulation. Furthermore, CEACAM1-engineered MSCs effectively inhibited the proliferation and activation of T cells along with the inflammatory responses of monocytes. In a humanized GvHD mouse model, CEACAM1-MSCs, particularly CEACAM1-4S-MSCs, demonstrated therapeutic potential by improving survival and alleviating symptoms. These findings suggest that CEACAM1 expression on MSCs contributes to MSC-mediated regulation of immune responses and that CEACAM1-engineered MSC could have therapeutic potential in conditions involving immune dysregulation.

Effects of the nerve growth factor and its carrier protein on the inflammatory response from human monocytes.

The nerve growth factor (NGF) has been previously shown to be involved in cellular proliferation, differentiation, survival, or wound healing. This factor displays a variety of biological effects that yet remain to be explored. Previous data on cell lines show a pro-inflammatory role of NGF on monocytes. The objective of the study was to investigate the pro-inflammatory effect of NGF, using a model of fresh human monocytes. Monocytes obtained from PBMC were exposed to NGF at various concentrations. Alternatively, monocytes were exposed to BSA, the NGF carrier protein without the NGF. Gene expression and cytokine release in the supernatant were monitored. We found that NGF increased the expression of pro-inflammatory, chemotactic, and remodeling genes such as interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and C-X-C motif ligand (CXCL)8. The protein levels of CXCL8 and matrix metalloproteinase (MMP)-9 were also increased in the cell supernatants following NGF exposure. BSA alone was found to drive part of this response, bringing nuance to the inflammatory potential of the NGF. These data suggest that NGF is able to enhance monocyte inflammatory responses once cells are stimulated with another signal but is possibly not able to directly activate it. This could have implications for example in patients with bacterial infections, where NGF could worsen the local inflammation by over-activating immune cells.

Monocyte response to SARS-CoV-2 protein ORF8 is associated with severe COVID-19 infection in patients with chronic lymphocytic leukemia.

The open reading frame 8 (ORF8) protein, encoded by the SARS-CoV-2 virus after infection, stimulates monocytes/macrophages to produce pro-inflammatory cytokines. We hypothesized that a positive ex vivo monocyte response to ORF8 protein pre-COVID-19 would be associated with subsequent severe Coronavirus disease 2019 (COVID-19). We tested ORF8 ex vivo on peripheral blood mononuclear cells from 26 anonymous healthy blood donors and measured intracellular cytokine/ chemokine levels in monocytes by flow cytometry. The percentage of positive monocyte staining in the sample and change in mean fluorescence intensity (ΔMFI) after ORF8 were used to calculate the adjusted MFI for each cytokine. We then tested pre-COVID-19 peripheral blood mononuclear cell samples from 60 chronic lymphocytic leukemia (CLL) patients who subsequently developed COVID-19 infection. Severe COVID-19 was defined as hospitalization due to COVID-19. In the 26 normal donor samples, the adjusted MFI for interleukin (IL)-1β, IL-6, IL-8, and CCL-2 were significantly different with ORF8 stimulation versus controls. We next analyzed monocytes from pre-COVID-19 PBMC samples from 60 CLL patients. The adjusted MFI to ORF8 stimulation of monocyte intracellular IL-1β was associated with severe COVID-19 and a reactive ORF8 monocyte response was defined as an IL-1β adjusted MFI ≥0.18 (sensitivity 67%, specificity 75%). The median time to hospitalization after infection in CLL patients with a reactive ORF8 response was 12 days versus not reached for patients with a non-reactive ORF8 response with a hazard ratio of 7.7 (95% confidence interval: 2.4-132; P=0.005). These results provide new insight on the monocyte inflammatory response to virus with implications in a broad range of disorders involving monocytes.

The association of TNF-alpha secretion and mtDNA copy number in CD14+ monocytes of patients with obesity and CHD.

Mitochondrial dysfunction may be one of the causes of inflammatory activation of monocytes and macrophages, which leads to excessive secretion of inflammatory mediators and the development of chronic inflammation. The study was aimed to evaluate the secretion of inflammatory cytokine tumor necrosis factor-α (TNF-α) in the primary culture of monocytes, and to analyze its relationship with the number of mitochondrial DNA (mtDNA) copies in the blood of patients with coronary heart disease (CHD) and obesity. 108 patients with obesity and concomitant CHD and a control group of 25 participants were included in the study. CD14+ monocytes were isolated by a standard method in a ficoll-urographin gradient, followed by separation using magnetic particles. The number of mtDNA copies was estimated using qPCR. It was demonstrated that the number of mtDNA copies was significantly increased in groups of patients with CHD and obesity + CHD in comparison with control group. mtDNA copy number positively correlated with basal and LPS-stimulated TNF-α secretion, the most significant correlation was found in the group of patients with CHD and obesity. Thus, the change in mtDNA copy number in CD14+ monocytes which indicates the presence of mitochondrial dysfunction, confirm the direct involvement of mitochondria in the violation of the inflammatory response of monocytes revealed in this study as an increased secretion of inflammatory cytokine TNF-α.

Features of the monocyte inflammatory response in patients with premature coronary artery disease monocyte inflammatory response in premature CAD

Features of the monocyte inflammatory response in patients with premature coronary artery disease monocyte inflammatory response in premature CAD

Flavonoid diversity and roles in the lipopolysaccharide-mediated inflammatory response of monocytes and macrophages.

Targeting lipopolysaccharide (LPS)/toll-like receptor4 signaling in mononuclear phagocytes has been explored for the treatment of inflammation and inflammation-related disorders. However, only a few key targets have been translated into clinical applications. Flavonoids, a class of ubiquitous plant secondary metabolites, possess a privileged scaffold which serves as a valuable template for designing pharmacologically active compounds directed against diseases with inflammatory components. This perspective provides a general overview of the diversity of flavonoids and their multifaceted mechanisms that interfere with LPS-induced signaling in monocytes and macrophages. Focus is placed on flavonoids targeting MD-2, IκB kinases, c-Jun N-terminal kinases, extracellular signal-regulated kinase, p38 MAPKand PI3K/Akt or modulating LPS-related gene expression.

Inflammatory Status of Monocytes in Type 2 Diabetes Mellitus

Сhronic inflammation is considered as a key factor in the development of type 2 diabetes mellitus. Impaired tolerance of the inflammatory response of monocytes is regarded as an important mechanism in the pathogenesis of chronic inflammation. In this work, we study the inflammatory activation and tolerance of the immune response of monocytes in diabetes. In total, 40 patients with newly diagnosed diabetes and 40 control group participants were included in the study. The level of basal, LPS-stimulated and re-stimulated secretion of the TNF-α, IL-1β, and MCP-1 cytokines was assessed in a monocyte culture isolated from the blood by immunomagnetic separation of CD14+ cells. The level of basal, LPS-stimulated and re-stimulated TNF-α secretion was significantly higher in patients with diabetes; the level of IL-1β secretion did not differ significantly between the groups; basal and re-stimulated MCP-1 secretion was also significantly higher in the diabetes group. Re-stimulated secretion of TNF-α and IL-1β was reduced compared to primary-stimulated secretion in both groups, demonstrating the tolerance of the macrophage immune response to these cytokines. Re-stimulated secretion of MCP-1 in 42% of diabetes patients was higher than primary stimulated secretion, thus revealing an impaired tolerance of the immune response of macrophages. A correlation was found between TNF-α secretion and body mass index, r=0.631, p<0.001, and with glycemic level, r=0.427, p=0.037. The results obtained demonstrate inflammatory activation of monocytes with hypersecretion of TNF-α and MCP-1, impaired tolerance of the immune response of monocytes in diabetes regarding the secretion of MCP-1, as well as a correlation of TNF-α secretion with body mass index and glycemic level. This indicates an important role of TNF-α and MCP-1 in the pathogenesis of chronic inflammation in type 2 diabetes, thus allowing these cytokines to be considered as potential therapeutic targets for pathogenetic therapy of type 2 diabetes.

Macrocystis pyrifera Lipids Reduce Cytokine-Induced Pro-Inflammatory Signalling and Barrier Dysfunction in Human Keratinocyte Models.

Atopic dermatitis is a chronic condition where epidermal barrier dysfunction and cytokine production by infiltrating immune cells exacerbate skin inflammation and damage. A total lipid extract from Macrocystis pyrifera, a brown seaweed, was previously reported to suppress inflammatory responses in monocytes. Here, treatment of human HaCaT keratinocytes with M. pyrifera lipids inhibited tumour necrosis factor (TNF)-α induced TNF receptor-associated factor 2 and monocyte chemoattractant protein (MCP)-1 protein production. HaCaT cells stimulated with TNF-α, interleukin (IL)-4, and IL-13 showed loss of claudin-1 tight junctions, but little improvement was observed following lipid pre-treatment. Three-dimensional cultures of HaCaT cells differentiated at the air-liquid interface showed increased MCP-1 production, loss of claudin-1 tight junctions, and trans-epidermal leakage with TNF-α, IL-4, and IL-13 stimulation, with all parameters reduced by lipid pre-treatment. These findings suggest that M. pyrifera lipids have anti-inflammatory and barrier-protective effects on keratinocytes, which may be beneficial for the treatment of atopic dermatitis or other skin conditions.

KSHV vIL-6 enhances inflammatory responses by epigenetic reprogramming.

Kaposi sarcoma-associated herpesvirus (KSHV) inflammatory cytokine syndrome (KICS) is a newly described chronic inflammatory disease condition caused by KSHV infection and is characterized by high KSHV viral load and sustained elevations of serum KSHV-encoded IL-6 (vIL-6) and human IL-6 (hIL-6). KICS has significant immortality and greater risks of other complications, including malignancies. Although prolonged inflammatory vIL-6 exposure by persistent KSHV infection is expected to have key roles in subsequent disease development, the biological effects of prolonged vIL-6 exposure remain elusive. Using thiol(SH)-linked alkylation for the metabolic (SLAM) sequencing and Cleavage Under Target & Release Using Nuclease analysis (CUT&RUN), we studied the effect of prolonged vIL-6 exposure in chromatin landscape and resulting cytokine production. The studies showed that prolonged vIL-6 exposure increased Bromodomain containing 4 (BRD4) and histone H3 lysine 27 acetylation co-occupancies on chromatin, and the recruitment sites were frequently co-localized with poised RNA polymerase II with associated enzymes. Increased BRD4 recruitment on promoters was associated with increased and prolonged NF-κB p65 binding after the lipopolysaccharide stimulation. The p65 binding resulted in quicker and sustained transcription bursts from the promoters; this mechanism increased total amounts of hIL-6 and IL-10 in tissue culture. Pretreatment with the BRD4 inhibitors, OTX015 and MZ1, eliminated the enhanced inflammatory cytokine production. These findings suggest that persistent vIL-6 exposure may establish a chromatin landscape favorable for the reactivation of inflammatory responses in monocytes. This epigenetic memory may explain the greater risk of chronic inflammatory disease development in KSHV-infected individuals.

Developmental Differences between Neonatal and Adult Platelets in Regard to Immune Protein Content and Regulation of Monocyte Inflammatory Responses

Preterm neonates frequently receive platelet transfusions (PTx), owing to their high incidence of thrombocytopenia and bleeding. However, a recent large randomized trial found a significantly higher incidence of death or major bleeding among more liberally transfused preterm neonates. The mechanisms underlying these deleterious effects are unknown, but it has been suggested that they are related to the developmental differences between adult and neonatal platelets, and to a potential “developmental mismatch” occurring when adult platelets (comparatively hyperreactive) are transfused into neonates. While most studies so far have focused on the hemostatic effects of PTx, it is now clear that platelets are key modulators of immune and inflammatory responses. We hypothesized that adult platelets would be more pro-inflammatory than neonatal platelets. To test this hypothesis, we first compared the proteome of resting cord blood (CB, n=9) and adult (n=7) platelets. Using data-independent acquisition mass spectrometry, we identified 4173 high-confidence proteins present in both adult and neonatal platelets. In a principal component analysis, neonatal and adult platelets clustered separately, and 359 proteins were present at significantly different relative abundances between the two groups (≥1.5-fold change, p<0.05). Pathway analysis of the 169 proteins significantly more abundant in the adult platelet proteome revealed enrichment for immune and inflammatory pathways, while neonatal platelets were enriched for pathways involved in metabolic processes. Next, we compared the effects of neonatal and adult platelets on the inflammatory response of human neonatal monocytes. Platelets and monocytes were isolated from healthy adult blood or full-term CB (n=6/group). Platelet P-selectin surface expression was determined by flow cytometry, and key platelet-derived immune regulators (RANTES, β-2 Microglobulin [β2M], and TGF-β) were quantified in the supernatant of resting and activated platelets by ELISA. After washing, neonatal and adult platelets had similarly low P-selectin surface expression levels. Following thrombin activation, P-selectin surface expression was significantly higher in adult than in neonatal platelets (MFI 4010±1645 vs. 1987±816, p=0.04). Thrombin activation increased RANTES and TGF-β release from adult and neonatal platelets to similar levels. In contrast, β2M levels were significantly higher in the supernatant from activated adult compared to neonatal platelets (37.9±10.2 vs 17.9±5.0 ng/mL, p=0.0004). Next, we co-cultured activated adult or neonatal platelets with neonatal monocytes and quantified the pro-inflammatory cytokines IL-8 and MCP-1 (CCL2) in the supernatants after 18 hours. The presence of activated platelets significantly increased IL-8 production from neonatal monocytes compared to monocytes alone, 2.9±1.2-fold when neonatal platelets were added and 4.2±1.8-fold with addition of adult platelets (p=0.01 and p=0.001, respectively). MCP-1 increased to similar levels with the addition of either neonatal or adult platelets. In a regression model, both P-selectin expression and platelet-released β2M levels were significantly associated with monocyte-produced IL-8 levels (p=0.001 and p=0.04, respectively). In summary, we found that proteins related to inflammatory and immune responses are more abundant in adult compared to neonatal platelets, and that activated adult platelets express more P-selectin and release more β2M than neonatal platelets, resulting in higher IL8 production by neonatal monocytes. These findings support the hypothesis that the pro-inflammatory effects of adult platelets might contribute to the increased morbidity and mortality associated with neonatal PTx.

Comparative effects of CFTR modulators on phagocytic, metabolic and inflammatory profiles of CF and nonCF macrophages

Macrophage dysfunction has been well-described in Cystic Fibrosis (CF) and may contribute to bacterial persistence in the lung. Whether CF macrophage dysfunction is related directly to Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) in macrophages or an indirect consequence of chronic inflammation and mucostasis is a subject of ongoing debate. CFTR modulators that restore CFTR function in epithelial cells improve global CF monocyte inflammatory responses but their direct effects on macrophages are less well understood. To address this knowledge gap, we measured phagocytosis, metabolism, and cytokine expression in response to a classical CF pathogen, Pseudomonas aeruginosa in monocyte-derived macrophages (MDM) isolated from CF F508del homozygous subjects and nonCF controls. Unexpectedly, we found that CFTR modulators enhanced phagocytosis in both CF and nonCF cohorts. CFTR triple modulators also inhibited MDM mitochondrial function, consistent with MDM activation. In contrast to studies in humans where CFTR modulators decreased serum inflammatory cytokine levels, modulators did not alter cytokine secretion in our system. Our studies therefore suggest modulator induced metabolic effects may promote bacterial clearance in both CF and nonCF monocyte-derived macrophages.

Inhibition of Cyclin-Dependent Kinases 8/19 Restricts Bacterial and Virus-Induced Inflammatory Responses in Monocytes.

Hyperactivation of the immune system remains a dramatic, life-threatening complication of viral and bacterial infections, particularly during pneumonia. Therapeutic approaches to counteract local and systemic outbreaks of cytokine storm and to prevent tissue damage remain limited. Cyclin-dependent kinases 8 and 19 (CDK8/19) potentiate transcriptional responses to the altered microenvironment, but CDK8/19 potential in immunoregulation is not fully understood. In the present study, we investigated how a selective CDK8/19 inhibitor, Senexin B, impacts the immunogenic profiles of monocytic cells stimulated using influenza virus H1N1 or bacterial lipopolysaccharides. Senexin B was able to prevent the induction of gene expression of proinflammatory cytokines in THP1 and U937 cell lines and in human peripheral blood-derived mononuclear cells. Moreover, Senexin B substantially reduced functional manifestations of inflammation, including clustering and chemokine-dependent migration of THP1 monocytes and human pulmonary fibroblasts (HPF).

Mycobacterium manresensis induces trained immunity in vitro

The COVID-19 pandemic posed a global health crisis, with new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants weakening vaccine-driven protection. Trained immunity could help tackle COVID-19 disease. Our objective was to analyze whether heat-killed Mycobacterium manresensis (hkMm), an environmental mycobacterium, induces trained immunity and confers protection against SARS-CoV-2 infection. To this end, THP-1 cells and primary monocytes were trained with hkMm. The increased secretion of tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-1β, and IL-10, metabolic activity, and changes in epigenetic marks suggested hkMm-induced trained immunity invitro. Healthcare workers at risk of SARS-CoV-2 infection were enrolled into the MANRECOVID19 clinical trial (NCT04452773) and were administered Nyaditum resae (NR, containing hkMm) or placebo. No significant differences in monocyte inflammatory responses or the incidence of SARS-CoV-2 infection were found between the groups, although NR modified the profile of circulating immune cell populations. Our results show that M.manresensis induces trained immunity invitro but not invivo when orally administered as NR daily for 14days.

Inflammatory and Immunologic Biomarkers Associated with Cognitive Impairment in Pediatric and Adolescent Patients with HIV in Lusaka, Zambia: A Sub-Study of the HIV-Associated Neurocognitive Disorders in Zambia (HANDZ) (P4-8.005)

<h3>Objective:</h3> Examine differences in monocyte populations and activated platelet-monocyte complexes between HIV-infected and HIV-exposed uninfected (HEU) populations Determine whether soluble biomarkers (including IL-6, sCD163, sCD14, CRP, TNFα, TNFR1, and TNFR2) are associated with cognitive function at baseline Determine whether soluble biomarkers are associated with neurocognitive changes over time <h3>Background:</h3> In 2018, 66,000 children in Zambia under 15 were HIV-positive. HIV is associated with neurocognitive impairment, and current antiretroviral therapy is not protective against some neurological impacts of chronic HIV infection, likely due to CNS inflammation. Though biomarkers conferring risk for neurocognitive impairment are unknown, biomarkers that have implications in monocyte activation and inflammatory response are strong candidates for investigation. Non-classical monocytes and activated platelet-monocyte complexes also play a role in chronic inflammation in the context of HIV, making them strong investigatory candidates, too. <h3>Design/Methods:</h3> This is a sub-study of the HIV-Associated Neurocognitive Disorders in Zambia (HANDZ) longitudinal prospective study, through which blood is collected annually. Soluble biomarker quantities were measured by Ella Multiplex Cytokine Analyzer. Classical, intermediate, and non-classical monocyte populations, and platelet-monocyte complexes were determined with flow cytometry. Cognitive function was assessed via a comprehensive neuropsychological testing battery and represented by NPZ8 scores. <h3>Results:</h3> Biomarkers sCD163, sCD14, CRP, and TNFα were significantly higher in concentration (p &lt; 0.05) in the HIV-infected cohort than in the HEU cohort. In contrast, TNF-R1, TNF-R2, and IL-6 were significantly higher in concentration (p &lt; 0.05) in the HEU cohort. When stratified by cognitive performance within cohorts, sCD163, CRP, TNF-R1, TNF-R2, and IL-6 were all found in significantly greater concentration (p &lt; 0.05) in neurocognitively impaired participants. <h3>Conclusions:</h3> Perinatally-acquired HIV is associated with increased levels of several inflammatory serum biomarkers, and biomarker profile characterized by high levels of inflammation and immune activation is associated with poorer cognitive outcomes in HIV-infected youth. <b>Disclosure:</b> Ms. Shah has nothing to disclose. Miss Kabwe has nothing to disclose. Ms. Molinaro has nothing to disclose. Dr. Metro has nothing to disclose. Esau G. Mbewe has received research support from Research was supported by the National Institute Of Neurological Disorders And Stroke of the National Institutes of Health under Award Number K23NS117310. . Pelekelo Kabundula has nothing to disclose. Milimo Mweemba has nothing to disclose. Sylvia Mwanza-Kabaghe has nothing to disclose. The institution of Heather Adams has received research support from Current: NIH; Past: Abeona; Batten Research Alliance; American University Centers on Disabilities. An immediate family member of Heather Adams has received publishing royalties from a publication relating to health care. Heather Adams has received personal compensation in the range of $500-$4,999 for serving as a Consultant with Critical Path Institute. An immediate family member of Dr. Birbeck has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Various. Dr. Birbeck has a non-compensated relationship as a Ambassador for Zambia with RSTMH that is relevant to AAN interests or activities. Dr. Bearden has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen. Dr. Bearden has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Praxis. Dr. Bearden has received personal compensation in the range of $100,000-$499,999 for serving as an Expert Witness for law firms.

Thiosulfinate-Enriched Allium sativum Extract Exhibits Differential Effects between Healthy and Sepsis Patients: The Implication of HIF-1α

Garlic (Allium sativum) has historically been associated with antioxidant, immunomodulatory, and microbiocidal properties, mainly due to its richness in thiosulfates and sulfur-containing phytoconstituents. Sepsis patients could benefit from these properties because it involves both inflammatory and refractory processes. We evaluated the effects of thiosulfinate-enriched Allium sativum extract (TASE) on the immune response to bacterial lipopolysaccharide (LPS) by monocytes from healthy volunteers (HVs) and patients with sepsis. We also explored the TASE effects in HIF-1α, described as the key transcription factor leading to endotoxin tolerance in sepsis monocytes through IRAK-M expression. Our results showed TASE reduced the LPS-triggered reactive oxygen species (ROS) production in monocytes from both patients with sepsis and HVs. Moreover, this extract significantly reduced tumor necrosis factor (TNF)-α, interleukin-1β, and interleukin-6 production in LPS-stimulated monocytes from HVs. However, TASE enhanced the inflammatory response in monocytes from patients with sepsis along with increased expression of human leukocyte antigen-DR. Curiously, these dual effects of TASE on immune response were also found when the HV cohort was divided into low- and high-LPS responders. Although TASE enhanced TNFα production in the LPS-low responders, it decreased the inflammatory response in the LPS-high responders. Furthermore, TASE decreased the HIF-1α pathway-associated genes IRAK-M, VEGFA and PD-L1 in sepsis cells, suggesting HIF-1α inhibition by TASE leads to higher cytokine production in these cells as a consequence of IRAK-M downregulation. The suppression of this pathway by TASE was confirmed in vitro with the prolyl hydroxylase inhibitor dimethyloxalylglycine. Our data revealed TASE's dual effect on monocyte response according to status/phenotype and suggested the HIF-1α suppression as the possible underlying mechanism.

Inflammatory and differentiation cellular response to calcium silicate cements: An in vitro study.

Inflammatory-regenerative cell interaction is believed to mediate hard tissue formation. This study aimed to investigate the interaction between human inflammatory monocytes with human regenerative fibroblasts after exposure to different calcium silicate materials. Human monocytes were cultured on three materials, polystyrene (PS), mineral trioxide aggregates (MTA) and biodentine (BD), in the presence or absence of lipopolysaccharide (LPS). Half of the monocyte-conditioned media (MoCM) of each group was used to analyse inflammatory cytokine secretion, namely TNF-α, IL-1β, IL-1RA and IL-6. The remaining MoCM was used to culture recipient fibroblasts, measuring the cell number (proliferation) and levels of alkaline phosphatase (differentiation) and lactic acid dehydrogenase (cytotoxicity). In absence of LPS, MTA was associated with higher secretion of TNF-α and lower secretion of IL-1β, while BD triggered higher secretions of both cytokines when both materials were compared to control (PS). When LPS was added, higher levels of all analysed cytokines were observed in the PS and BD groups, whereas for the MTA group, only TNF-α and IL-6 were increased. Fibroblasts responded differently to the MoCM from the different groups, revealing significant increases in proliferation and differentiation capacities, particularly when cultured in CM from monocytes exposed to MTA. The morphological evaluation revealed different patterns of fibroblast shape and spread in the different MoCM groups. Calcium silicate materials modulate the monocyte inflammatory response, which subsequently induce differential effects on the recipient fibroblasts. MTA appears to promote the secretion of prodifferentiation signals from the monocytes, which are received by fibroblasts, promoting their proliferation and differentiation. The model represents a promising tool to evaluate the interaction of different cells in response to different materials.

Endotoxin tolerance and low activation of TLR-4/NF-κB axis in monocytes of COVID-19 patients.

Higher endotoxin in the circulation may indicate a compromised state of host immune response against coinfections in severe COVID-19 patients. We evaluated the inflammatory response of monocytes from COVID-19 patients after lipopolysaccharide (LPS) challenge. Whole blood samples of healthy controls, patients with mild COVID-19, and patients with severe COVID-19 were incubated with LPS for 2h. Severe COVID-19 patients presented higher LPS and sCD14 levels in the plasma than healthy controls and mild COVID-19 patients. In non-stimulated in vitro condition, severe COVID-19 patients presented higher inflammatory cytokines and PGE-2 levels and CD14 + HLA-DRlow monocytes frequency than controls. Moreover, severe COVID-19 patients presented higher NF-κB p65 phosphorylation in CD14 + HLA-DRlow, as well as higher expression of TLR-4 and NF-κB p65 phosphorylation in CD14 + HLA-DRhigh compared to controls. The stimulation of LPS in whole blood of severe COVID-19 patients leads to lower cytokine production but higher PGE-2 levels compared to controls. Endotoxin challenge with both concentrations reduced the frequency of CD14 + HLA-DRlow in severe COVID-19 patients, but the increases in TLR-4 expression and NF-κB p65 phosphorylation were more pronounced in both CD14 + monocytes of healthy controls and mild COVID-19 patients compared to severe COVID-19 group. We conclude that acute SARS-CoV-2 infection is associated with diminished endotoxin response in monocytes. KEY MESSAGES: Severe COVID-19 patients had higher levels of LPS and systemic IL-6 and TNF-α. Severe COVID-19 patients presented higher CD14+HLA-DRlow monocytes. Increased TLR-4/NF-κB axis was identified in monocytes of severe COVID-19. Blunted production of cytokines after whole blood LPS stimulation in severe COVID-19. Lower TLR-4/NF-κB activation in monocytes after LPS stimulation in severe COVID-19.

Retraction notice for: "miR-141 is negatively correlated with TLR4 in neonatal sepsis and regulates LPS-induced inflammatory responses in monocytes" [Braz J Med Biol Res (2021) 54(7): e10603

[This retracts the article doi: 10.1590/1414-431x2020e10603].