The Modulation of Septic Shock: A Proteomic Approach.

Sepsis poses a significant challenge due its lethality, involving multiple organ dysfunction and impaired immune responses. Among several factors affecting sepsis, monocytes play a crucial role; however, their phenotype, proteomic profile, and function in septic shock remain unclear. Our aim was to fully characterize the subpopulations and proteomic profiles of monocytes seen in septic shock cases and discuss their possible impact on the disease. Peripheral blood monocyte subpopulations were phenotype based on CD14/CD16 expression by flow cytometry, and proteins were extracted from the monocytes of individuals with septic shock and healthy controls to identify changes in the global protein expression in these cells. Analysis using 2D-nanoUPLC-UDMSE identified 67 differentially expressed proteins in shock patients compared to controls, in which 44 were upregulated and 23 downregulated. These proteins are involved in monocyte reprogramming, immune dysfunction, severe hypotension, hypo-responsiveness to vasoconstrictors, vasodilation, endothelial dysfunction, vascular injury, and blood clotting, elucidating the disease severity and therapeutic challenges of septic shock. This study identified critical biological targets in monocytes that could serve as potential biomarkers for the diagnosis, prognosis, and treatment of septic shock, providing new insights into the pathophysiology of the disease.

Novel Clinical, Immunological, and Metabolic Features Associated with Persistent Post-Acute COVID-19 Syndrome.

The coronavirus disease 2019 (COVID-19) survivors are frequently observed to present persistent symptoms constituting what has been called "post-acute COVID-19 syndrome" (PACS) or "long COVID-19". Some clinical risk factors have been identified to be associated with PACS development; however, specific mechanisms responsible for PACS pathology remain unknown. This study investigates clinical, immunological, and metabolomic risk factors associated with post-acute COVID-19 syndrome (PACS) in 51 patients, assessed 7-19 months after acute infection. Among the participants, 62.7% were male and 37.2% were female, with an average age of 47.8 years. At the follow-up, 37.2% met the criteria for PACS, revealing significant differences in immunological and metabolomic profiles at the time of acute infection. Patients with PACS were characterized by elevated levels of mature low-density granulocytes (LDGs), interleukin-8 (IL-8), pyruvate, pseudouridine, and cystine. Baseline multivariate analysis showed increased pyruvate and decreased alpha tocopherol levels. At follow-up, there was a decrease in absolute B lymphocytes and an increase in non-classical monocytes and 3-hydroxyisovaleric acid levels. These findings suggest that specific immunological and metabolomic markers during acute infection can help identify patients at higher risk of developing persistent PACS.

Involvement of Expression of miR33-5p and ABCA1 in Human Peripheral Blood Mononuclear Cells in Coronary Artery Disease.

MicroRNAs (miRs) are small non-coding RNAs that regulate gene expression post-transcriptionally and are crucial in lipid metabolism. ATP-binding cassette transporter A1 (ABCA1) is essential for cholesterol efflux from cells to high-density lipoprotein (HDL). Dysregulation of miRs targeting ABCA1 can affect cholesterol homeostasis and contribute to coronary artery disease (CAD). This study aimed to investigate the expression of miRs targeting ABCA1 in human monocytes, their role in cholesterol efflux, and their relationship with CAD. We included 50 control and 50 CAD patients. RT-qPCR examined the expression of miR-33a-5p, miR-26a-5p, and miR-144-3p in monocytes. Logistic regression analysis explored the association between these miRs and CAD. HDL's cholesterol acceptance was analyzed using the J774A.1 cell line. Results showed that miR-26a-5p (p = 0.027) and ABCA1 (p = 0.003) expression levels were higher in CAD patients, while miR-33a-5p (p < 0.001) levels were lower. Downregulation of miR-33a-5p and upregulation of ABCA1 were linked to a lower CAD risk. Atorvastatin upregulated ABCA1 mRNA, and metformin downregulated miR-26a-5p in CAD patients. Decreased cholesterol efflux correlated with higher CAD risk and inversely with miRs in controls. Reduced miR-33a-5p expression and increased ABCA1 expression are associated with decreased CAD risk. miR deregulation in monocytes may influence atherosclerotic plaque formation by regulating cholesterol efflux. Atorvastatin and metformin could offer protective effects by modulating miR-33a-5p, miR-26a-5p, and ABCA1, suggesting potential therapeutic strategies for CAD prognosis and treatment.

Food grade titanium dioxide (E171) interferes with monocyte-macrophage cell differentiation and their phagocytic capacity.

Food grade titanium dioxide E171 has been used in products such as confectionery, doughs and flours to enhance organoleptic properties. The European Union has warned about adverse effects on humans due to oral consumption. After oral exposure, E171 reaches the bloodstream which raises the concern about effects on blood cells such as monocytes. One of the main functions of these cells is the differentiation of macrophages leading to the phagocytosis of foreign particles. The aim of this study was to evaluate the effect of E171 exposure on the phagocytic capacity and differentiation process of monocytes (THP-1) into macrophages. Physicochemical E171 properties were evaluated, and THP-1 monocytes were exposed to 4, 40 and 200 µg/ml. Cell viability, uptake capacity, cytokine release, the differentiation process, cytoskeletal arrangement and E171 internalization were assayed. Results showed that E171 particles had an amorphous shape with a mean of hydrodynamic size of ∼46 nm in cell culture media. Cell viability decreased until the 9th day of exposure, while the uptake capacity decreased up to 62% in a concentration dependent manner in monocytes. Additionally, the E171 exposure increased the proinflammatory cytokines release and decreased the cell differentiation by a 61% in macrophages. E171 induced changes in cytoskeletal arrangement and some of the E171 particles were located inside the nuclei. We conclude that E171 exposure in THP-1 monocytes induced an inflammatory response, impaired the phagocytic capacity, and interfered with cell differentiation from monocytes to macrophages.

Alveolar macrophages and monocyte subpopulations during Plasmodium berghei NK65 experimental malaria-associated acute respiratory distress syndrome.

Alveolar macrophages (AM) and monocytes (MO) are myeloid cells that play a substantial role in the development and establishment of the innate and adaptive immune response. These cells are crucial for host defense against various pathogens, but their role in malaria is poorly understood. Here, we characterize the dynamics of AMs and recruited leukocytes subpopulations in the airways during experimental Plasmodium berghei NK65-NY (PbNK65). We show that PbNK65 infection induces an increased pulmonary vascular permeability that provides Ly6Clow MOs, neutrophils (NEU), CD4+ and CD8+ lymphocytes in the airways. This inflammatory environment resulted in an increase in the population and alteration of the activation state of the AMs. Taken together, the data presented provide new insights into airway inflammation associated with pulmonary malaria.

PIWI pathway: bridging acute myeloid leukemia stemness and cellular differentiation.

PIWI proteins are stem cell-associated RNA-binding proteins crucial for survival of germ stem cells. In cancer, PIWI proteins are overexpressed. Specifically, PIWIL4 is highly expressed in multiple cancers with the highest levels found in acute myeloid leukemia (AML), an aggressive malignancy propagated by a population of leukemia stem cells (LSCs). Bamezai et al. (Blood Journal, blood, 2023, 142, 90-105) demonstrated that PIWIL4 supports AML blasts and LSCs but is not necessary for healthy human hematopoietic progenitor stem cells (HSPCs) function in vivo. PIWIL4 in AML acts by preventing the accumulation of R-loops in key genes for LSCs persistence implicated in: DNA damage, replicative stress, and transcription arrest. We report that PIWIL4 expression significantly decreases in THP-1 monocytes exposed to a differentiating agent, suggesting a potential role for PIWIL4 in maintaining the undifferentiated state of myeloid cells. PIWIL4 overexpression could lead to the emergence of LSCs, driving leukemia propagation and maintenance. Our findings correlate with the persistent overexpression of PIWIL4 in myeloid cancers as reported by Bamezai et al., and suggest that PIWIL4 may be involved in myeloid cell differentiation. In this perspective, we highlight recent findings on the implication of PIWI pathway in maintaining AML stemness. Additionally, we propose further investigation on the role of PIWI pathway in oncogenesis and cellular differentiation as a strategy to identify biomarkers and therapeutic targets for AML.

Cytotoxicity, pro-inflammatory cytokines gene expression and antioxidant activity of Acmella oleracea extract treated with active charcoal.

This work reports for the first time the evaluation of the cytotoxicity and inflammatory potential of Acmella oleracea extract treated with active charcoal in THP-1 monocytes. A. oleracea flower ethanolic extract was treated with 4% activated charcoal (TCEE). Later, THP-1 human monocyte cytotoxicity assay was performed using resazurin fluorometric method. Gene expression of inflammatory cytokines in THP-1 cells were evaluated through RT-PCR by ΔΔCt method using IL-1ß, IL-6, IL-8, and TNF genes primers. Finally, antioxidant assay was carried out with DPPH radical scavenging method. TCEE had a LD50 of 592.5 µg/mL and did not induce pro-inflammatory gene expression in THP-1 cells after 6 h of treatment. Lastly, TCEE (AA% of 69.4 ± 1.4%) and CEE (AA% of 63.0 ± 0.9%) showed moderate antioxidant activity. A. oleracea treated flower extract showed low cytotoxicity in THP-1 monocytes and does not induce inflammation in THP-1 cells, in addition to presenting antioxidant potential.

Extracellular vesicles from primary human macrophages stimulated with VIP or PACAP mediate anti-SARS-CoV-2 activities in monocytes through NF-κB signaling pathway.

Infection by SARS-CoV-2 is associated with uncontrolled inflammatory response during COVID-19 severe disease, in which monocytes are one of the main sources of pro-inflammatory mediators leading to acute respiratory distress syndrome. Extracellular vesicles (EVs) from different cells play important roles during SARS-CoV-2 infection, but investigations describing the involvement of EVs from primary human monocyte-derived macrophages (MDM) on the regulation of this infection are not available. Here, we describe the effects of EVs released by MDM stimulated with the neuropeptides VIP and PACAP on SARS-CoV-2-infected monocytes. MDM-derived EVs were isolated by differential centrifugation of medium collected from cells cultured for 24 h in serum-reduced conditions. Based on morphological properties, we distinguished two subpopulations of MDM-EVs, namely large (LEV) and small EVs (SEV). We found that MDM-derived EVs stimulated with the neuropeptides inhibited SARS-CoV-2 RNA synthesis/replication in monocytes, protected these cells from virus-induced cytopathic effects and reduced the production of pro-inflammatory mediators. In addition, EVs derived from VIP- and PACAP-treated MDM prevented the SARS-CoV-2-induced NF-κB activation. Overall, our findings suggest that MDM-EVs are endowed with immunoregulatory properties that might contribute to the antiviral and anti-inflammatory responses in SARS-CoV-2-infected monocytes and expand our knowledge of EV effects during COVID-19 pathogenesis.

Myeloproliferative Neoplasms Transcriptome Reveals Pro-Inflammatory Signature and Enrichment in Peripheral Blood Monocyte-Related Genes.

Myeloproliferative neoplasms (MPN) are hematological diseases associated with genetic driver mutations in the JAK2, CALR, and MPL genes and exacerbated oncoinflammatory status. Analyzing public microarray data from polycythemia vera (n = 41), essential thrombocythemia (n = 21), and primary myelofibrosis (n = 9) patients' peripheral blood by in silico approaches, we found that pro-inflammatory and monocyte-related genes were differentially expressed in MPN patients' transcriptome. Genes related to cell activation, secretion of pro-inflammatory and pro-angiogenic mediators, activation of neutrophils and platelets, coagulation, and interferon pathway were upregulated in monocytes compared to controls. Together, our results suggest that molecular alterations in monocytes may contribute to oncoinflammation in MPN.

Thirty days of double-strain probiotic supplementation increases monocyte phagocytosis in marathon runners.

Marathon runners, subjected to intense training regimens and prolonged, exhaustive exercises, often experience a compromised immune response. Probiotic supplementation has emerged as a potential remedy to mitigate the impact of prolonged exercise on athletes. Consequently, this study sought to assess the influence of probiotic supplementation on monocyte functionality both before and after the official marathon race. Twenty-seven runners were randomly and double-blindly assigned to two groups: placebo (n 13) and probiotic (PRO) (n 14). Over 30 d, both groups received supplements - placebo sachets containing maltodextrin (5 g/d) and PRO sachets containing 1 × 1010 colony-forming unit Lactobacillus acidophilus and 1 × 1010 colony-forming unit Bifidobacterium bifidum subsp. lactis. Blood samples were collected, and immunological assays, including phagocytosis, hydrogen peroxide production, cytokine levels and monocyte immunophenotyping, were conducted at four different intervals: baseline (start of supplementation/30 d pre-marathon), 24 h-before (1 d pre-marathon), 1 h-after (1 h post-marathon) and 5 d-after (5 d post-marathon). Monocyte populations remained consistent throughout the study. A notable increase in phagocytosis was observed in the PRO group after 30 d of supplementation. Upon lipopolysaccharide stimulation, both PRO and placebo groups exhibited decreased IL-8 production. However, after the marathon race, IL-15 stimulation demonstrated increased levels of 5 d-after, while IL-1-ß, IL-8, IL-10, IL-15 and TNF-α varied across different intervals, specifically within the PRO group. Probiotic supplementation notably enhanced the phagocytic capacity of monocytes. However, these effects were not sustained post-marathon.

Transcriptomic signatures of classical monocytes reveal pro-inflammatory modules and heterogeneity in polyarticular juvenile idiopathic arthritis.

Introduction: Polyarticular juvenile idiopathic arthritis (pJIA) is a childhood-onset autoimmune disease. Immune cells contribute to persistent inflammation observed in pJIA. Despite the crucial role of monocytes in arthritis, the precise involvement of classical monocytes in the pathogenesis of pJIA remains uncertain. Here, we aimed to uncover the transcriptomic patterns of classical monocytes in pJIA, focusing on their involvement in disease mechanism and heterogeneity. Methods: A total of 17 healthy subjects and 18 premenopausal women with pJIA according to ILAR criteria were included. Classical monocytes were isolated, and RNA sequencing was performed. Differential expression analysis was used to compare pJIA patients and healthy control group. Differentially expressed genes (DEGs) were identified, and gene set enrichment analysis (GSEA) was performed. Using unsupervised learning approach, patients were clustered in two groups based on their similarities at transcriptomic level. Subsequently, these clusters underwent a comparative analysis to reveal differences at the transcriptomic level. Results: We identified 440 DEGs in pJIA patients of which 360 were upregulated and 80 downregulated. GSEA highlighted TNF-α and IFN-γ response. Importantly, this analysis not only detected genes targeted by pJIA therapy but also identified new modulators of immuno-inflammation. PLAUR, IL1B, IL6, CDKN1A, PIM1, and ICAM1 were pointed as drivers of chronic hyperinflammation. Unsupervised learning approach revealed two clusters within pJIA, each exhibiting varying inflammation levels. Conclusion: These findings indicate the pivotal role of immuno-inflammation driven by classical monocytes in pJIA and reveals the existence of two subclusters within pJIA, regardless the positivity of rheumatoid factor and anti-CCP, paving the way to precision medicine.

Elevated glycolytic metabolism of monocytes limits the generation of HIF1A-driven migratory dendritic cells in tuberculosis.

During tuberculosis (TB), migration of dendritic cells (DCs) from the site of infection to the draining lymph nodes is known to be impaired, hindering the rapid development of protective T-cell-mediated immunity. However, the mechanisms involved in the delayed migration of DCs during TB are still poorly defined. Here, we found that infection of DCs with Mycobacterium tuberculosis (Mtb) triggers HIF1A-mediated aerobic glycolysis in a TLR2-dependent manner, and that this metabolic profile is essential for DC migration. In particular, the lactate dehydrogenase inhibitor oxamate and the HIF1A inhibitor PX-478 abrogated Mtb-induced DC migration in vitro to the lymphoid tissue-specific chemokine CCL21, and in vivo to lymph nodes in mice. Strikingly, we found that although monocytes from TB patients are inherently biased toward glycolysis metabolism, they differentiate into poorly glycolytic and poorly migratory DCs compared with healthy subjects. Taken together, these data suggest that because of their preexisting glycolytic state, circulating monocytes from TB patients are refractory to differentiation into migratory DCs, which may explain the delayed migration of these cells during the disease and opens avenues for host-directed therapies for TB.

PLGA-LEC/F127 hybrid nanoparticles loaded with curcumin and their modulatory effect on monocytes.

Aim: To investigate the effect of surfactant type on curcumin-loaded (CUR) PLGA nanoparticles (NPs) to modulate monocyte functions. Materials & methods: The nanoprecipitation method was used, and PLGA NPs were designed using Pluronic F127 (F127) and/or lecithin (LEC) as surfactants. Results: The Z-average of the NPs was <200 nm, they had a spherical shape, Derjaguin-Muller-Toporov modulus >0.128 MPa, they were stable during storage at 4°C, ζ-potential ∼-40 mV, polydispersity index <0.26 and % EE of CUR >94%. PLGA-LEC/F127 NPs showed favorable physicochemical and nanomechanical properties. These NPs were bound and internalized mainly by monocytes, suppressed monocyte-induced reactive oxygen species production, and decreased the ability of monocytes to modulate T-cell proliferation. Conclusion: These results demonstrate the potential of these NPs for targeted therapy.

This study explores how different surfactants affect curcumin-loaded PLGA nanoparticles, a biodegradable polymer. The nanoparticles were designed using Pluronic F127 and/or lecithin as surfactants. They are less than 200 nm and spherical. They are stable when stored at 4 °C, with a surface charge of about -40 mV, and can encapsulate more than 94% of curcumin.The results of this study are promising, showing that PLGA nanoparticles using a mixture of lecithin and Pluronic F127 as surfactants have favorable properties toward monocyte adhesion. They are primarily taken up by monocytes, a type of white blood cell, and demonstrate a remarkable ability to reduce the production of reactive oxygen species, which can cause cell damage, as well as the ability of monocytes to stimulate the proliferation of T cells. This underscores the potential of these nanoparticles in targeted therapy, particularly in diseases where monocytes play a pivotal role, such as chronic inflammatory conditions.

Listeria monocytogenesy mecanismo de caballo de Troya a través de la barrera hematoencefálica / isteria monocytogenesand Trojan horse mechanism across the blood-brain barrier

Las infecciones del sistema nervioso central son potencialmente mortales, causadas por patógenos, como bacterias, virus y hongos. Para llegar hasta el cerebro, los microorganismos utilizan diversas vías y formas. Este patogeno es una bacteria grampositiva corta, flagelar e intracelular, con la capacidad de inducir su internalización en células fagocíticas (monocitos/macrófagos) y no fagocíticas (células endoteliales). Al infectar los macrófagos, estos microorganismos se valen de su capacidad de fijación, adhesión y migración transendotelial, para cruzar la barrera hematoencefálica, finalmente, generando meningitis bacteriana. En esta revisión describimos el mecanismo de caballo de Troya usado por Listeria monocytogenespara invadir el cerebro en el desarrollo de enfermedades infecciosas e incorporamos nuevos conocimientos sobre moléculas que intervienen en dicho mecanismo(AU)

Central nervous system infections are life-threatening, caused by pathogens such as bacteria, viruses and fungi. To access the brain, microorganisms use various mechanisms. Listeria monocytogenes is a short, flagellar and intracellular gram-positive bacterium, with the ability to induce its internalization in phagocytic (monocytes/macrophages) and non-phagocytic (endothelial cells) cells. By infecting macrophages, these microorganisms take advantage of their binding, adhesion, and transendothelial migrationcapacity to cross the blood-brain barrier, finally generating bacterial meningitis. In this review we describe the Trojan horse mechanism used by Listeria monocytogenesto invade the brain in the development of infectious diseases and we incorporate new knowledge about molecules that intervene in this mechanism(AU)

Leishmania braziliensis enhances monocyte responses to promote anti-tumor activity.

Innate immune cells can undergo long-term functional reprogramming after certain infections, a process called trained immunity (TI). Here, we focus on antigens of Leishmania braziliensis, which induced anti-tumor effects via trained immunity in human monocytes. We reveal that monocytes exposed to promastigote antigens of L. braziliensis develop an enhanced response to subsequent exposure to Toll-like receptor (TLR)2 or TLR4 ligands. Mechanistically, the induction of TI in monocytes by L. braziliensis is mediated by multiple pattern recognition receptors, changes in metabolism, and increased deposition of H3K4me3 at the promoter regions of immune genes. The administration of L. braziliensis exerts potent anti-tumor capabilities by delaying tumor growth and prolonging survival of mice with non-Hodgkin lymphoma. Our work reveals mechanisms of TI induced by L. braziliensis in vitro and identifies its potential for cancer immunotherapy.

Human metapneumovirus respiratory infection affects both innate and adaptive intestinal immunity.

Introduction: Respiratory infections are one of the leading causes of morbidity and mortality worldwide, mainly in children, immunocompromised people, and the elderly. Several respiratory viruses can induce intestinal inflammation and alterations in intestinal microbiota composition. Human metapneumovirus (HMPV) is one of the major respiratory viruses contributing to infant mortality in children under 5 years of age worldwide, and the effect of this infection at the gut level has not been studied. Methods: Here, we evaluated the distal effects of HMPV infection on intestinal microbiota and inflammation in a murine model, analyzing several post-infection times (days 1, 3, and 5). Six to eight-week-old C57BL/6 mice were infected intranasally with HMPV, and mice inoculated with a non-infectious supernatant (Mock) were used as a control group. Results: We did not detect HMPV viral load in the intestine, but we observed significant changes in the transcription of IFN-γ in the colon, analyzed by qPCR, at day 1 post-infection as compared to the control group. Furthermore, we analyzed the frequencies of different innate and adaptive immune cells in the colonic lamina propria, using flow cytometry. The frequency of monocyte populations was altered in the colon of HMPV -infected mice at days 1 and 3, with no significant difference from control mice at day 5 post-infection. Moreover, colonic CD8+ T cells and memory precursor effector CD8+ T cells were significantly increased in HMPV-infected mice at day 5, suggesting that HMPV may also alter intestinal adaptive immunity. Additionally, we did not find alterations in antimicrobial peptide expression, the frequency of colonic IgA+ plasma cells, and levels of fecal IgA. Some minor alterations in the fecal microbiota composition of HMPV -infected mice were detected using 16s rRNA sequencing. However, no significant differences were found in ß-diversity and relative abundance at the genus level. Discussion: To our knowledge, this is the first report describing the alterations in intestinal immunity following respiratory infection with HMPV infection. These effects do not seem to be mediated by direct viral infection in the intestinal tract. Our results indicate that HMPV can affect colonic innate and adaptive immunity but does not significantly alter the microbiota composition, and further research is required to understand the mechanisms inducing these distal effects in the intestine.

Janus kinase inhibitors modify the fatty acid profile of extracellular vesicles and modulate the immune response.

Background: Janus kinase inhibitors (jakinibs) are immunomodulators used for treating malignancies, autoimmune diseases, and immunodeficiencies. However, they induce adverse effects such as thrombosis, lymphocytosis, and neutropenia that could be mediated by extracellular vesicles (EVs). These particles are cell membrane-derived structures that transport cellular and environmental molecules and participate in intercellular communication. Jakinibs can modify the content of EVs and enable them to modulate the activity of different components of the immune response. Objective: to evaluate the interactions between immune system components of healthy individuals and EVs derived from monocytic and lymphoid lineage cells generated in the presence of baricitinib (BARI) and itacitinib (ITA) and their possible effects. Methods: EVs were isolated from monocytes (M) and lymphocytes (L) of healthy individuals, as well as from U937 (U) and Jurkat (J) cells exposed to non-cytotoxic concentrations of BARI, ITA, and dimethyl sulfoxide (DMSO; vehicle control). The binding to and engulfment of EVs by peripheral blood leukocytes of healthy individuals were analyzed by flow cytometry using CFSE-stained EVs and anti-CD45-PeCy7 mAb-labeled whole blood. The effect of EVs on respiratory burst, T-cell activation and proliferation, cytokine synthesis, and platelet aggregation was evaluated. Respiratory burst was assessed in PMA-stimulated neutrophils by the dihydrorhodamine (DHR) test and flow cytometry. T-cell activation and proliferation and cytokine production were assessed in CFSE-stained PBMC cultures stimulated with PHA; expression of the T-cell activation markers CD25 and CD69 and T-cell proliferation were analyzed by flow cytometry, and the cytokine levels were quantified in culture supernatants by Luminex assays. Platelet aggregation was analyzed in platelet-rich plasma (PRP) samples by light transmission aggregometry. The EVs' fatty acid (FA) profile was analyzed using methyl ester derivatization followed by gas chromatography. Results: ITA exposure during the generation of EVs modified the size of the EVs released; however, treatment with DMSO and BARI did not alter the size of EVs generated from U937 and Jurkat cells. Circulating neutrophils, lymphocytes, and monocytes showed a 2-fold greater tendency to internalize ITA-U-EVs than their respective DMSO control. The neutrophil respiratory burst was attenuated in greater extent by M-EVs than by L-EVs. Autologous ITA-M-EVs reduced T-cell proliferation by decreasing IL-2 levels and CD25 expression independently of CD69. A higher accumulation of pro-inflammatory cytokines was observed in PHA-stimulated PBMC cultures exposed to M-EVs than to L-EVs; this difference may be related to the higher myristate content of M-EVs. Platelet aggregation increased in the presence of ITA-L/M-EVs by a mechanism presumably dependent on the high arachidonic acid content of the vesicles. Conclusions: Cellular origin and jakinib exposure modify the FA profile of EVs, enabling them, in turn, to modulate neutrophil respiratory burst, T-cell proliferation, and platelet aggregation. The increased T-cell proliferation induced by BARI-L/M-EVs could explain the lymphocytosis observed in patients treated with BARI. The higher proportion of arachidonic acid in the FA content of ITA-L/M-EVs could be related to the thrombosis described in patients treated with ITA. EVs also induced a decrease in the respiratory burst of neutrophils.

Classical monocytes-low expressing HLA-DR is associated with higher mortality rate in SARS-CoV-2+ young patients with severe pneumonia.

Aims: This study aimed to investigate whether monocyte dysregulation and hyperinflammation serve as predictive markers for mortality in young patients with SARS-CoV-2 severe pneumonia. Methods: A prospective cohort study was conducted in a tertiary-level public University Hospital in Colombia. Forty young adults (18-50 years of age) with severe pneumonia and SARS-CoV-2 infection confirmed by qPCR, were enrroled. Serum cytokines and the monocyte phenotype profile, including PDL1/HLA-DR expression, were determined during the first 24 h of hospitalization. Routine laboratory parameters were measured throughout patient follow-up until either death or hospital discharge. We also included a cohort of twenty-five healthy control subjects. Key findings: Elevated levels of IL-10, IL-8, and IL-6 cytokines emerged as robust predictors of mortality in young adults with severe pneumonia due to SARS-CoV-2 infected. A descriptive analysis revealed a cumulative mortality rate of 30 % in unvaccinated and ICU-admitted patients. Patients who died had significantly lower expression of HLA-DR on their classical monocytes subsets (CD14+CD16-) than survivors and healthy controls. Lower expression of HLA-DR was associated with greater clinical severity (APACHE≥12) and bacterial coinfection (relative risk 2.5 95%CI [1.18-5.74]). Notably, the expression of HLA-DR in 27.5 % of CD14+/CD16- monocytes was associated with a significantly lower probability of survival. Significance: The early reduction in HLA-DR expression within classical monocytes emerged as an independent predictor of mortality, irrespective of comorbidities. Together with PD-L1 expression and cytokine alterations, these findings support the notion that monocyte immunosuppression plays a fundamental role in the pathogenesis and mortality of young patients infected with SARS-CoV-2. These findings hold significant implications for risk assessment and therapeutic strategies in managing critically ill young adults with SARS-CoV-2 infection.

Effect of photobiomodulation on inflammatory cytokines produced by HaCaT keratinocytes.

Objective: to evaluate the effects of the red and near-infrared wavelength lasers in isolated and simultaneous way on the modulation of inflammatory cytokines produced by human keratinocytes (HaCaT) challenged by cytokines of human monocytes stimulated by lipopolysaccharide from Escherichia coli. Design: HaCaT cells was previously exposed to the laser with wavelengths red (660 nm), near-infrared (808 nm). Then, HaCat cells were stimulated with the supernatant of lipopolysaccharide-challenged peripheral blood cells. The cytokines expressed by HaCat cells were measured using multiplex CBA assay. Results: HaCaT cells increased the production of inflammatory cytokines when stimulated with infrared laser compared to the control group (IFN-α2, IFN-γ, TNF-α, MCP-1, IL-6, IL-8, IL-10, IL -12p70, IL -17A, IL-23, IL-33), the red laser group (IFN-γ and IL-23) and the group of two lasers used simultaneously (IFN-α2, IFN-γ, IL-6 and IL-8, IL-17A, IL-18 and IL-23) (p < 0.05). The red laser also stimulated an increase in the expression of IFN-α2 by HaCaT cells in relation to the control group (p < 0.05). Conclusion: Infrared laser, with an energy density of 5 J/cm2, appear to be able to modulate inflammatory cytokines produced by HaCaT cells challenged by human monocyte cytokines.