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Overweight and obesity are typical conditions of chronic low-intensity systemic inflammatory responses, and both have become more common in recent decades, which emphasizes the necessity for healthier diet intake. Fruits such as grapes are rich in anthocyanins, one of which is delphinidin, a promising chemopreventive agent with anti-inflammatory properties. Considering that polymorphonuclear cells (PMNs) are rapidly mobilized to tissues when the inflammatory process is initiated, this study aimed to understand the impact of grape juice intake and delphinidin on the migration properties of PMNs. Overweight women ingested 500 mL of grape juice for 28 days, and then lipid and inflammatory profiles, as well as the white blood cell count (WBC), were evaluated. Additionally, the gene expression of inflammatory markers and quantified migration molecules such as CD11/CD18, ICAM-1 and VCAM-1 were evaluated in PMNs. The influence of delphinidin-3-O-glucoside in vitro on some migration properties was also evaluated. Grape juice intake did not influence the lipid profile or affect the WBC. However, NFκB gene expression was reduced in PMNs, also reducing the circulating values of IL-8, sICAM-1, and sVCAM-1. The in vitro results demonstrated that delphinidin significantly reduced the migration potential of cells and reduced CD11-/CD18-positive cells, the gene expression of ICAM-1, and the phosphorylation and gene expression of NFκB. Additionally, delphinidin also reduced the production of IL-6, IL-8, and CCL2. Grape juice, after 28 days of intervention, influenced some properties related to cell migration, and delphinidin in vitro can modify the cell migration properties.

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Branched-chain amino acids (BCAA) are essential for maintaining intestinal mucosal integrity. However, only a few studies have explored the role of BCAA in the modulation of intestinal inflammation. In this study, we investigated in vitro effects of BCAA on the inflammatory response induced by lipopolysaccharide (LPS) (1 µg/mL) in Caco-2 cells. Caco-2 cells were assigned to six groups: control without BCAA (CTL0), normal BCAA (CTL; 0.8 mM leucine, 0.8 mM isoleucine, and 0.8 mM valine); leucine (LEU; 2 mM leucine), isoleucine (ISO; 2 mM isoleucine), valine (VAL; 2 mM valine), and high BCAA (LIV; 2 mM leucine, 2 mM isoleucine, and 2 mM valine). BCAA was added to the culture medium 24 h before LPS stimulation. Our results indicated that BCAA supplementation did not impair cell viability. The amino acids leucine and isoleucine attenuated the synthesis of IL-8 and JNK and NF-kB phosphorylation induced by LPS. Furthermore, neither BCAA supplementation nor LPS treatment modulated the activity of glutathione peroxidase or the intracellular reduced glutathione/oxidized glutathione ratio. Therefore, leucine and isoleucine exert anti-inflammatory effects in Caco-2 cells exposed to LPS by modulating JNK and NF-kB phosphorylation and IL-8 production. Further in vivo studies are required to validate these findings and gather valuable information for potential therapeutic or dietary interventions.

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Protein malnourishment (PM) is common among the elderly, but how aging and PM impact hematopoiesis is not fully understood. This study aimed to assess how aging and PM affect the hematopoietic regulatory function of bone marrow (BM) mesenchymal stem cells (MSCs). Young and aged male C57BL/6J mice were fed with normoproteic or hypoproteic diets and had their nutritional, biochemical, and hematological parameters evaluated. BM MSCs were characterized and had their secretome, gene expression, autophagy, reactive oxygen species production (ROS), and DNA double-stranded breaks evaluated. The modulation of hematopoiesis by MSCs was assayed using in vitro and in vivo models. Lastly, BM invasiveness and mice survival were evaluated after being challenged with leukemic cells of the C1498 cell line. Aging and PM alter biochemical parameters, changing the peripheral blood and BM immunophenotype. MSC autophagy was affected by aging and the frequencies for ROS and DNA double-stranded breaks. Regarding the MSCs' secretome, PM and aging affected CXCL12, IL-6, and IL-11 production. Aging and PM up-regulated Akt1 and PPAR-γ while down-regulating Cdh2 and Angpt-1 in MSCs. Aged MSCs increased C1498 cell proliferation while reducing their colony-forming potential. PM and aging lowered mice survival, and malnourishment accumulated C1498 cells at the BM. Finally, aged and/or PM MSCs up-regulated Sox2, Nanog, Pou5f1, and Akt1 expression while down-regulating Cdkn1a in C1498 cells. Together, aging and PM can induce cell-intrinsic shifts in BM MSCs, creating an environment that alters the regulation of hematopoietic populations and favoring the development of malignant cells.

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The bone marrow is responsible for producing an incredible number of cells daily in order to maintain blood homeostasis through a process called hematopoiesis. Hematopoiesis is a greatly demanding process and one entirely dependent on complex interactions between the hematopoietic stem cell (HSC) and its surrounding microenvironment. Zinc (Zn2+) is considered an important trace element, playing diverse roles in different tissues and cell types, and zinc finger proteins (ZNF) are proteins that use Zn2+ as a structural cofactor. In this way, the ZNF structure is supported by a Zn2+ that coordinates many possible combinations of cysteine and histidine, with the most common ZNF being of the Cys2His2 (C2H2) type, which forms a family of transcriptional activators that play an important role in different cellular processes such as development, differentiation, and suppression, all of these being essential processes for an adequate hematopoiesis. This review aims to shed light on the relationship between ZNF and the regulation of the hematopoietic tissue. We include works with different designs, including both in vitro and in vivo studies, detailing how ZNF might regulate hematopoiesis.

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There has been a global increase in the older population in recent decades and, as age advances, complex metabolic and epigenetic changes occur in the organism, and these may trigger some health complications commonly found among this population. Additionally, several changes occur in older people that can reduce the dietary intake or the process of nutrient absorption. In this way, tissues with high nutrient requirements are more affected. Hematopoiesis is the process of formation, development, and maturation of blood cells and is a process with a high turnover. This high demand makes the integrity of the hematopoietic process susceptible to various factors that impair physiological function, such as aging and micronutrient bioavailability. Among these micronutrients, Zinc is considered an important micronutrient, playing diverse roles across various tissues and cell types. Some of the alterations in hematopoiesis that appear as a consequence of aging and due to insufficient micronutrient intake are well described in the literature; however, not much is known about how zinc deficiency contributes towards the development of diseases seen in aging. Considering the importance of zinc to act on several biological processes, this narrative review discusses several studies related to the physiological requirements, deficiency, or excess of zinc, including studies in experimental models and humans, and aimed to shed light on the relationship between zinc and the regulation of hematopoietic tissue, exploring possible links between this mineral with common disorders that appear during aging.

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Blood orange consumption presents potential health benefits and may modulate epigenetic mechanisms such as microRNAs (miRNAs) expression. MiRNAs are non-coding RNAs responsible for post-transcriptional gene regulation, and these molecules can also be used as biomarkers in body fluids. This study was designed to investigate the effect of chronic blood orange juice (BOJ) intake on the inflammatory response and miRNA expression profile in plasma and blood cells in overweight women. The study cohort was comprised of twenty women aged 18-40 years old, diagnosed as overweight, who consumed 500 mL/d of BOJ for four weeks. Clinical data were collected at baseline and after 4 weeks of juice consumption, e.g., anthropometric and hemodynamic parameters, food intake, blood cell count, and metabolic and inflammatory biomarkers. BOJ samples were analyzed and characterized. Additionally, plasma and blood cells were also collected for miRNA expression profiling and evaluation of the expression of genes and proteins in the MAPK and NFκB signaling pathways. BOJ intake increased the expression of miR-144-3p in plasma and the expression of miR-424-5p, miR-144-3p, and miR-130b-3p in peripheral blood mononuclear cells (PBMC). Conversely, the beverage intake decreased the expression of let-7f-5p and miR-126-3p in PBMC. Computational analyses identified different targets of the dysregulated miRNA on inflammatory pathways. Furthermore, BOJ intake increased vitamin C consumption and the pJNK/JNK ratio and decreased the expression of IL6 mRNA and NFκB protein. These results demonstrate that BOJ regulates the expression of genes involved in the inflammatory process and decreases NFкB-protein expression in PBMC.

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OBJECTIVE: Anthocyanins are polyphenols that are promising chemopreventive agents. They stand out for their anti-inflammatory properties, with specific modulatory actions on the immune system. Additionally, regarding the immune system, a group of cells identified as mesenchymal stem cells (MSCs) have been attracting attention, mainly because of their capacity to migrate to sites of inflammation and produce potent immunomodulatory effects. Considering the ability of these cells to act on the immune system, as well as the properties of anthocyanins, especially delphinidin, in modulating the immune system, the aim of this study was to investigate the effects of delphinidin in influencing some immunoregulatory properties of MSCs. METHODS: MSCs were cultivated in the presence of delphinidin 3-O-ß-d-glycoside and cell viability, the cell cycle and the production of soluble factors (interleukin [IL]-1ß, IL-6, IL-10, transforming growth factor [TGF]-ß, prostaglandin E2 [PGE2] and nitric oxide [NO]) were evaluated, as was the expression of the transcription factors nuclear factor (NF)-κB and STAT3. Additionally, the effects of conditioned media from MSCs on macrophage activation were assessed. RESULTS: Delphinidin at 50 µM does not affect cell viability. In association with lipopolysaccharide, delphinidin was able to induce MSC proliferation. Additionally, delphinidin modulated the MSC immune response, showing increased levels of anti-inflammatory cytokines such as IL-10 and TGF-ß as well as lower expression of NF-κB. Furthermore, conditioned media from MSCs inhibited macrophage metabolism, reducing the production of IL-1ß, IL-12, and TNF-α and increasing IL-10. CONCLUSIONS: Overall, this work showed that delphinidin can modify the immunomodulatory properties of MSCs, increasing the IL-10 production by macrophages.

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Malnutrition is considered one of the most common problems in the elderly population worldwide and can significantly interfere in health evolution in these individuals, predisposing them to increased infection susceptibility. The immune response triggered by infections comprises several mechanisms, and macrophages play important roles in this response. This study aimed to evaluate mechanisms related to macrophage function in a model of protein malnutrition in the elderly. Two age groups (young: 3-5 months and elderly: 18-19 months) male C57BL/6NTac mice were subjected to protein malnutrition with a low-protein diet (2 %). The nutritional status, hemogram and number of peritoneal cells were affected by both age and nutritional status. Additionally, the spreading capacity as well as the phagocytic and fungicidal activity of peritoneal macrophages were affected by the nutritional status and age of the animal. Interestingly, the percentages of F4/80+/CD11b+ and CD86+ cells were reduced mostly in elderly animals, while the TLR-4+ population was more affected by nutritional status than by age. The production of pro-inflammatory cytokines such as TNF-α, IL-1α, and IL-6 was also influenced by nutritional status and/or by age, and malnourished animals of advanced age produced higher amounts of the anti-inflammatory cytokine IL-10. Furthermore, the phosphorylation ratio of the transcription factor NFκB (pNFκB/NFκB) was directly affected by the nutritional status, independently of age. Thus, these results allow us to conclude that aging and protein malnutrition compromise macrophage function, likely affecting their immune function, and in aged protein-malnourished animals, this impairment tends to be more pronounced.

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Reliable serological tests for the detection of SARS-CoV-2 antibodies among infected or vaccinated individuals are important for epidemiological and clinical studies. Low-cost approaches easily adaptable to high throughput screenings, such as Enzyme-Linked Immunosorbent Assays (ELISA) or electrochemiluminescence immunoassay (ECLIA), can be readily validated using different SARS-CoV-2 antigens. A total of 1,119 serum samples collected between March and July of 2020 from health employees and visitors to the University Hospital at the University of São Paulo were screened with the Elecsys® Anti-SARS-CoV-2 immunoassay (Elecsys) (Roche Diagnostics) and three in-house ELISAs that are based on different antigens: the Nucleoprotein (N-ELISA), the Receptor Binding Domain (RBD-ELISA), and a portion of the S1 protein (ΔS1-ELISA). Virus neutralization test (CPE-VNT) was used as the gold standard to validate the serological assays. We observed high sensitivity and specificity values with the Elecsys (96.92% and 98.78%, respectively) and N-ELISA (93.94% and 94.40%, respectively), compared with RBD-ELISA (90.91% sensitivity and 88.80% specificity) and the ΔS1-ELISA (77.27% sensitivity and 76% specificity). The Elecsys® proved to be a reliable SARS-CoV-2 serological test. Similarly, the recombinant SARS-CoV-2 N protein displayed good performance in the ELISA tests. The availability of reliable diagnostic tests is critical for the precise determination of infection rates, particularly in countries with high SARS-CoV-2 infection rates, such as Brazil. Collectively, our results indicate that the development and validation of new serological tests based on recombinant proteins may provide new alternatives for the SARS-CoV-2 diagnostic market.

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PURPOSE: Dietary protein deficiency is common in the elderly, compromising hematopoiesis and the immune response, and may cause a greater susceptibility to infections. Mesenchymal stem cells (MSCs) have immunomodulatory properties and are essential to hematopoiesis. Therefore, this study aimed to investigate, in an aging model subjected to malnutrition due a reduced protein intake, aspects related to the immunomodulatory capacity of MSCs. METHODS: Male C57BL/6 mice from young and elderly groups were fed with normoproteic or hypoproteic diets (12% and 2% of protein, respectively) and nutritional, biochemical and hematological parameters were evaluated. MSCs from bone marrow were isolated, characterized and their secretory parameters evaluated, along with gene expression. Additionally, the effects of aging and protein malnutrition on MSC immunomodulatory properties were assessed. RESULTS: Malnourished mice lost weight and demonstrated anemia, leukopenia, and bone marrow hypoplasia. MSCs from elderly animals from both groups showed reduced CD73 expression and higher senescence rate; also, the malnourished state affected CD73 expression in young animals. The production of IL-1ß and IL-6 by MSCs was affected by aging and malnutrition, but the IL-10 production not. Aging also increased the expression of NFκB, reducing the expression of STAT-3. However, MSCs from malnourished groups, regardless of age, showed decreased TGF-ß and PGE2 production. Evaluation of the immunomodulatory capacity of MSCs revealed that aging and malnutrition affected, mainly in lymphocytes, the production of IFN-γ and IL-10. CONCLUSION: Aging and reduced protein intake are factors that, alone or together, influence the immunomodulatory properties of MSCs and provide basic knowledge that can be further investigated to explore whether MSCs' therapeutic potential may be affected.

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The conditions of aquatic environments have a great influence on the microbiota of several animals, many of which are a potential source of microorganisms of biotechnological interest. In this study, bacterial strains isolated from aquatic environments were bioprospected to determine their probiotic profile and antimicrobial effect against fish and food pathogens. Two isolates, identified via 16S rRNA sequencing as Lactococcus lactis (L1 and L2) and one as Enterococcus faecium 135 (EF), produced a bacteriocin-like antimicrobial substance (BLIS), active against Listeria monocytogenes, Salmonella Choleraesuis and Salmonella Typhimurium. Antimicrobial activity of BLIS was reduced when exposed to high temperatures and proteolytic enzymes (trypsin, pepsin, papain and pancreatin). All strains were sensitive to 7 types of antibiotics (vancomycin, clindamycin, streptomycin, gentamicin, chloramphenicol, rifampicin and ampicillin), exhibited a high rate of adherence to Caco-2 cells and expressed no hemolysin and gelatinase virulence factors. EF showed some resistance at pH 2.5 and 3.0, and L2/EF showed higher resistance to the action of bile salts. Finally, the presence of bacteriocin genes encoding for proteins, including Nisin (L1 and L2), Enterocin A, B, P, and Mundticin KS (EF) was detected. The molecular and physiological evidence suggests that the bacterial isolates in this study could be used as natural antimicrobial agents and may be considered safe for probiotic application.

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Purpose: This study aimed to evaluate the radiation-induced direct and bystander (BYS) responses of mesenchymal stem cells (MSCs) and to characterize these cells radiobiologically.Methods and materials: MSCs were irradiated (IR) and parameters related to DNA damage and cellular signaling were verified in a dose range from 0.5 to 15 Gy; also a transwell insert co-culture system was used to study medium-mediated BYS effects.Results: The main effects on directly IR cells were seen at doses higher than 6 Gy: induction of cell death, cell cycle arrest, upregulation of p21, and alteration of redox status. Irrespective of a specific dose, induction of micronuclei formation, H2AX phosphorylation, and decreased Akt expression also occurred. Thus, mTOR expression, cell senescence, nitric oxide generation, and calcium levels, in general were not significantly modulated by radiation. Data from the linear-quadratic model showed a high alpha/beta ratio, which is consistent with a more exponential survival curve. BYS effects from the unirradiated MSCs placed into companion wells with the directly IR cells, were not observed.Conclusions: The results can be interpreted as a positive outcome, meaning that the radiation damage is restricted to the directed IR MSCs not leading to off-target cell responses.

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In the course of infection and intense endotoxemia processes, induction of a catabolic state leading to weight loss is observed in mice and humans. However, the late effects of acute inflammation on energy homeostasis, regulation of body weight and glucose metabolism are yet to be elucidated. Here, we addressed whether serial intense endotoxemia, characterized by an acute phase response and weight loss, could be an aggravating or predisposing factor to weight gain and associated metabolic complications. Male Swiss Webster mice were submitted to 8 consecutive doses of lipopolysaccharide (10 mg/kg LPS), followed by 10 weeks on a high-fat diet (HFD). LPS-treated mice did not show changes in weight when fed standard chow. However, when challenged by a high-fat diet, LPS-treated mice showed greater weight gain, with larger fat depot areas, increased serum leptin and insulin levels and impaired insulin sensitivity when compared to mice on HFD only. Acute endotoxemia caused a long-lasting increase in mRNA expression of inflammatory markers such as TLR-4, CD14 and serum amyloid A (SAA) in the adipose tissue, which may represent the key factors connecting inflammation to increased susceptibility to weight gain and impaired glucose homeostasis. In an independent experimental model, and using publicly available microarray data from adipose tissue from mice infected with Gram-negative bacteria, we performed gene set enrichment analysis and confirmed upregulation of a set of genes responsible for cell proliferation and inflammation, including TLR-4 and SAA. Together, we showed that conditions leading to intense and recurring endotoxemia, such as common childhood bacterial infections, may resound for a long time and aggravate the effects of a western diet. If confirmed in humans, infections should be considered an additional factor contributing to obesity and type 2 diabetes epidemics.

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Anemia is a common feature of chronic kidney disease (CKD). It is a process related to erythropoietin deficiency, shortened erythrocyte survival, uremic erythropoiesis inhibitors, and disordered iron homeostasis. Animal models of CKD-induced anemia are missing and would be desirable in order to study anemia mechanisms and facilitate the development of novel therapeutic tools. We induced three different models of CKD in mice and evaluated the development of anemia characteristics. Mice were subjected to unilateral ischemia-reperfusion or received repeated low doses of cisplatin or folic acid to induce nephropathy. Renal function, kidney injury and fibrotic markers were measured to confirm CKD. Moreover, serum hemoglobin, ferritin and erythropoietin were analyzed. Renal mRNA levels of HIF-2α, erythropoietin, hepcidin, GATA-2, and GATA-2 target genes were also determined. All three CKD models presented increased levels of creatinine, urea, and proteinuria. Renal up-regulation of NGAL, KIM-1, and TNF-α mRNA levels was observed. Moreover, the three CKD models developed fibrosis and presented increased fibrotic markers and α-SMA protein levels. CKD induced decreased hemoglobin and ferritin levels and increased erythropoietin levels in the serum. Renal tissue showed decreased erythropoietin and HIF-2α mRNA levels, while an increase in the iron metabolism regulator hepcidin was observed. GATA-2 transcription factor (erythropoietin repressor) mRNA levels were increased in all CKD models, as well as its target genes. We established three models of CKD-induced anemia, regardless of the mechanism and severity of kidney injury.

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The perivascular adipose tissue (PVAT) differs from other fat depots and exerts a paracrine action on the vasculature. The spleen has an important role in the immune response, and it was observed to have either a protective role or a contribution to obesity-related diseases. However, the relation between spleen and PVAT is elusive in obesity. We investigated the role of spleen in the inflammatory profile of the mesenteric PVAT (mPVAT) from mice fed a high-fat diet (HFD) for 16 weeks. Male C57Bl/6 mice were sham-operated or splenectomized (SPX) and fed a HFD for 16 weeks. mPVAT morphology was evaluated by hematoxylin and eosin staining, infiltrated immune cells were evaluated by flow cytometry, inflammatory cytokines were evaluated by ELISA and the splenic cell chemotaxis mediated by mPVAT was evaluated using a transwell assay. In SPX mice, HFD induced adipocyte hypertrophy and increased immune cell infiltration and proinflammatory cytokine levels in mPVAT. However, none of these effects were observed in mPVAT from sham-operated mice. Spleen from HFD fed mice presented reduced total leukocytes and increased inflammatory markers when compared to the spleen from control mice. Chemotaxis of spleen cells mediated by mPVAT of HFD fed mice was reduced in relation to standard diet fed mice. The spleen protects mPVAT against the effects of 16-week HFD. This information was missing, and it is important because PVAT is different from other fat depots and data cannot be extrapolated from any type of adipose tissue to PVAT.

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Although branched-chain amino acids (BCAA) are commonly used as a strategy to recover nutritional status of critically ill patients, recent findings on their role as immunonutrients have been associated with unfavorable outcomes, especially in obese patients. The present study aimed to explore the effects of different BCAA supplementation protocols in the inflammatory response of LPS-stimulated RAW 264.7 macrophages. Cell cultures were divided into five groups, with and without BCAA supplementation, (2 mmol/L of each amino acid). Then, cell cultures followed three different treatment protocols, consisting of a pretreatment (PT), an acute treatment (AT), and a chronic treatment (CT) with BCAA and LPS stimulation (1 µg/mL). Cell viability was analyzed by MTT assay, NO production was assessed by the Griess reaction and IL-6, IL-10, TNF-α and PGE2 synthesis, was evaluated by ELISA. BCAA significantly increased cell viability in AT and CT protocols, and NO and IL-10 synthesis in all treatment protocols. IL-6 synthesis was only increased in PT and CT protocols. TNF-α and PGE2 synthesis were not altered in any of the protocols and groups. BCAA supplementation was able to increase both pro and anti-inflammatory mediators synthesis by RAW 264.7 macrophages, which was influenced by the protocol applied. Moreover, these parameters were significantly increased by isoleucine supplementation, highlighting a potential research field for future studies.

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Protein malnutrition causes anemia and leukopenia as it reduces hematopoietic precursors and impairs the production of mediators that regulate hematopoiesis. Hematopoiesis occurs in distinct bone marrow niches that modulate the processes of differentiation, proliferation and self-renewal of hematopoietic stem cells (HSCs). Mesenchymal stem cells (MSCs) contribute to the biochemical composition of bone marrow niches by the secretion of several growth factors and cytokines, and they play an important role in the regulation of HSCs and hematopoietic progenitors. In this study, we investigated the effect of protein malnutrition on the hematopoietic regulatory function of MSCs. C57BL/6NTaq mice were divided into control and protein malnutrition groups, which received, respectively, a normal protein diet (12% casein) and a low protein diet (2% casein). The results showed that protein malnutrition altered the synthesis of SCF, TFG-ß, Angpt-1, CXCL-12, and G-CSF by MSCs. Additionally, MSCs from the protein malnutrition group were not able to maintain the lymphoid, granulocytic and megakaryocytic-erythroid differentiation capacity compared to the MSCs of the control group. In this way, the comprehension of the role of MSCs on the regulation of the hematopoietic cells, in protein malnutrition states, is for the first time showed. Therefore, we infer that hematopoietic alterations caused by protein malnutrition are due to multifactorial alterations and, at least in part, the MSCs' contribution to hematological impairment.

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BACKGROUND & AIMS: Magnesium (Mg2+) is able to modulate the differentiation and proliferation of cells. Mg2+ restriction can trigger neutrophilia, but the processes that result in this change have yet to be investigated and are not fully understood. Hematopoiesis is a complex process that is regulated by many factors, including cytokines and growth factors, and is strongly influenced by nutrient availability. In this context, our objective was to investigate the impact of the short-term restriction of dietary Mg2+ on bone marrow hematopoietic and peripheral blood cells, especially in processes related to granulocyte differentiation and proliferation. METHODS: Male C57BL/6 mice were fed a Mg2+ restricted diet (50 mg Mg2+/kg diet) for 4 weeks. Cell blood count and bone marrow cell count were evaluated. Bone marrow cells were also characterized by flow cytometry. Gene expression and cytokine production were evaluated, and a colony-forming cell assay related to granulocyte differentiation and proliferation was performed. RESULTS: Short-term dietary restriction of Mg2+ resulted in peripheral neutrophilia associated with an increased number of granulocytic precursors in the bone marrow. Additionally, Mg2+ restriction resulted in an increased number of granulocytic colonies formed in vitro. Moreover, the Mg2+ restricted group showed increased expression of CSF3 and CEBPα genes as well as increased production of G-CSF in association with increased expression of STAT3 protein. CONCLUSION: Short-term dietary restriction of Mg2+ induces granulopoiesis by increasing G-CSF production and activating the CEBPα and STAT-3 pathways, resulting in neutrophilia in peripheral blood.

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BACKGROUND: The role of myeloid-derived suppressor cells (MDSCs) in patients with severe tuberculosis who suffer from uncontrolled pulmonary inflammation caused by hypervirulent mycobacterial infection remains unclear. METHODS: This issue was addressed using C57BL/6 mice infected with highly virulent Mycobacterium bovis strain MP287/03. RESULTS: CD11b+GR1int population increased in the bone marrow, blood and lungs during advanced disease. Pulmonary CD11b+GR1int (Ly6GintLy6Cint) cells showed granularity similar to neutrophils and expressed immature myeloid cell markers. These immature neutrophils harbored intracellular bacilli and were preferentially located in the alveoli. T-cell suppression occurred concomitantly with CD11b+GR1int cell accumulation in the lungs. Furthermore, lung and bone marrow GR1+ cells suppressed both T-cell proliferation and interferon γ production in vitro. Anti-GR1 therapy given when MDSCs infiltrated the lungs prevented expansion and fusion of primary pulmonary lesions and the development of intragranulomatous caseous necrosis, along with increased mouse survival and partial recovery of T-cell function. Lung bacterial load was reduced by anti-GR1 treatment, but mycobacteria released from the depleted cells proliferated extracellularly in the alveoli, forming cords and clumps. CONCLUSIONS: Granulocytic MDSCs massively infiltrate the lungs during infection with hypervirulent mycobacteria, promoting bacterial growth and the development of inflammatory and necrotic lesions, and are promising targets for host-directed therapies.

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Ionizing radiation (IR) is an important medical tool. Despite the effects associated with high-dose radiation during or after treatment, as well as in accidental exposures, the direct or indirect effect of low-dose IR in cells remain poorly documented. IR can affect the tissue microenvironment, including mesenchymal stem cells (MSCs), which have high regenerative and immunomodulatory capacities. This study aimed to investigate the effect of low-dose IR in association with the inflammatory stimuli of TNF-α on the immunomodulatory capacity of MSCs. MSCs were irradiated with a low-dose IR, stimulated with TNF-α, and cultivated in a bystander system with murine spleen cells. The results showed that TNF-R1 is expressed in MSCs and is not affected, even in irradiated MSCs. However, irradiated MSCs produced reduced amounts of IL-6 and increased amounts of IL-10. The levels of PGE2 and NO• in MSCs were also increased when stimulated with TNF-α. Furthermore, conditioned media from irradiated MSCs reduced the proliferation of bystander lymphocytes and reduced the metabolic activity of macrophages. In addition, conditioned media from irradiated MSCs modulated the profile of cytokines in bystander spleen cells (lymphocytes and macrophages), reducing inflammatory and increasing anti-inflammatory cytokines, also increasing Treg cells. In conclusion, low-dose IR in association with an inflammatory stimulus affects the immunomodulatory properties of MSCs. In this way, the immunosuppressive capability of MSCs can be explored for several disease treatments where IR usually part of the context of the treatment. However, a complete understanding of the mechanisms underlying these interactions need further investigation. Graphical Abstract.

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