The influence of association between aging and reduced protein intake on some immunomodulatory aspects of bone marrow mesenchymal stem cells: an experimental study.

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.

Effects of different branched-chain amino acids supplementation protocols on the inflammatory response of LPS-stimulated RAW 264.7 macrophages.

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.

A Review of the Action of Magnesium on Several Processes Involved in the Modulation of Hematopoiesis.

Magnesium (Mg2+) is an essential mineral for the functioning and maintenance of the body. Disturbances in Mg2+ intracellular homeostasis result in cell-membrane modification, an increase in oxidative stress, alteration in the proliferation mechanism, differentiation, and apoptosis. Mg2+ deficiency often results in inflammation, with activation of inflammatory pathways and increased production of proinflammatory cytokines by immune cells. Immune cells and others that make up the blood system are from hematopoietic tissue in the bone marrow. The hematopoietic tissue is a tissue with high indices of renovation, and Mg2+ has a pivotal role in the cell replication process, as well as DNA and RNA synthesis. However, the impact of the intra- and extracellular disturbance of Mg2+ homeostasis on the hematopoietic tissue is little explored. This review deals specifically with the physiological requirements of Mg2+ on hematopoiesis, showing various studies related to the physiological requirements and the effects of deficiency or excess of this mineral on the hematopoiesis regulation, as well as on the specific process of erythropoiesis, granulopoiesis, lymphopoiesis, and thrombopoiesis. The literature selected includes studies in vitro, in animal models, and in humans, giving details about the impact that alterations of Mg2+ homeostasis can have on hematopoietic cells and hematopoietic tissue.

Gemfibrozil Induces Anemia, Leukopenia and Reduces Hematopoietic Stem Cells via PPAR-α in Mice.

Hypercholesterolemia, also called high cholesterol, is a form of hyperlipidemia, which may be a consequence of diet, obesity or diabetes. In addition, increased levels of low-density lipoprotein (LDL) and reduced levels of high-density lipoprotein (HDL) cholesterol are associated with a higher risk of atherosclerosis and coronary heart disease. Thus, controlling cholesterol levels is commonly necessary, and fibrates have been used as lipid-lowering drugs. Gemfibrozil is a fibrate that acts via peroxisome proliferator-activated receptor alpha to promote changes in lipid metabolism and decrease serum triglyceride levels. However, anemia and leukopenia are known side effects of gemfibrozil. Considering that gemfibrozil may lead to anemia and that gemfibrozil acts via peroxisome proliferator-activated receptor alpha, we treated wild-type and peroxisome proliferator-activated receptor alpha-knockout mice with gemfibrozil for four consecutive days. Gemfibrozil treatment led to anemia seven days after the first administration of the drug; we found reduced levels of hemoglobin, as well as red blood cells, white blood cells and a reduced percentage of hematocrits. PPAR-alpha-knockout mice were capable of reversing all of those reduced parameters induced by gemfibrozil treatment. Erythropoietin levels were increased in the serum of gemfibrozil-treated animals, and we also observed an increased expression of hypoxia-inducible factor-2 alpha (HIF-2α) and erythropoietin in renal tissue, while PPAR-alpha knockout mice treated with gemfibrozil did not present increased levels of serum erythropoietin or tissue HIF-2α and erythropoietin mRNA levels in the kidneys. We analyzed bone marrow and found that gemfibrozil reduced erythrocytes and hematopoietic stem cells in wild-type mice but not in PPAR-alpha-knockout mice, while increased colony-forming units were observed only in wild-type mice treated with gemfibrozil. Here, we show for the first time that gemfibrozil treatment leads to anemia and leukopenia via peroxisome proliferator-activated receptor alpha in mice.

Exogenous glutamine impairs neutrophils migration into infections sites elicited by lipopolysaccharide by a multistep mechanism.

Glutamine (GLN) is the most abundant free amino acid in the body, and is considered as a conditionally essential amino acid under stress conditions, acting as an important modulator of the immune response. We here investigated the role of exogenous GLN treatment on leukocyte migration after the onset of endotoxemia and the intracellular mechanisms of GLN actions on neutrophils. Two in vivo models of endotoxemia caused by lipopolysaccharide of Escherichia coli (LPS) injection were carried out in male outbred Balb/C mice 2-3 months old, as follow: (1) LPS (50 µg/kg) was intravenously injected 1 h prior to intravenous injection of GLN (0.75 mg/kg) and samples were collected 2 h later to investigate the role of GLN on the acute lung inflammation; (2) LPS (1 mg/kg) was intraperitoneally injected 1 h prior to intravenous injection of GLN (0.75 mg/kg) and samples were collected 18 h later to measure the effects of GLN on local and later phases of inflammation in the peritoneum. Results showed that GLN administration reduced the number of neutrophils in the inflamed lungs, partially recovery of the reduced number of leukocytes in the blood; reduced adhesion molecules on lung endothelium and on circulating neutrophils. Moreover, GLN treatment diminished the number of neutrophils, levels of chemotactic cytokine CXCL2 in the inflamed peritoneum, and neutrophils collected from the peritoneum of GLN-treated mice presented lower levels of Rho, Rac, and JNK. Together, our data show novel mechanisms involved in the actions of GLN on neutrophils migration.

A review of select minerals influencing the haematopoietic process.

Micronutrients are indispensable for adequate metabolism, such as biochemical function and cell production. The production of blood cells is named haematopoiesis and this process is highly consuming due to the rapid turnover of the haematopoietic system and consequent demand for nutrients. It is well established that micronutrients are relevant to blood cell production, although some of the mechanisms of how micronutrients modulate haematopoiesis remain unknown. The aim of the present review is to summarise the effect of Fe, Mn, Ca, Mg, Na, K, Co, iodine, P, Se, Cu, Li and Zn on haematopoiesis. This review deals specifically with the physiological requirements of selected micronutrients to haematopoiesis, showing various studies related to the physiological requirements, deficiency or excess of these minerals on haematopoiesis. The literature selected includes studies in animal models and human subjects. In circumstances where these minerals have not been studied for a given condition, no information was used. All the selected minerals have an important role in haematopoiesis by influencing the quality and quantity of blood cell production. In addition, it is highly recommended that the established nutrition recommendations for these minerals be followed, because cases of excess or deficient mineral intake can affect the haematopoiesis process.

Effects of glutamine, taurine and their association on inflammatory pathway markers in macrophages.

The immune system is essential for the control and elimination of infections, and macrophages are cells that act as important players in orchestrating the various parts of the inflammatory/immune response. Amino acids play important role in mediating functionality of the inflammatory response, especially mediating macrophages functions and cytokines production. We investigated the influence of glutamine, taurine and their association on the modulation of inflammatory pathway markers in macrophages. The RAW 264.7 macrophage cell line was cultivated in the presence of glutamine and taurine and proliferation rates, cell viability, cell cycle phases, IL-1α, IL-6, IL-10 and TNF-α as well as H2O2 production and the expression of the transcription factor, NFκB, and its inhibitor, IκBα, were evaluated. Our results showed an increase in viable cells and increased proliferation rates of cells treated with glutamine concentrations over 2 mM, as well as cells treated with both glutamine and taurine. The cell cycle showed a higher percentage of cells in the phases S, G2 and M when they were treated with 2 or 10 mM glutamine, or with glutamine and taurine in cells stimulated with lipopolysaccharide. The pNFκB/NFκB showed reduced ratio expression when cells were treated with 10 mM of glutamine or with glutamine in association with taurine. These conditions also resulted in reduced TNF-α, IL-1α and H2O2 production, and higher production of IL-10. These findings demonstrate that glutamine and taurine are able to modulate macrophages inflammatory pathways, and that taurine can potentiate the effects of glutamine, illustrating their immunomodulatory properties.

Annexin A1 Is a Physiological Modulator of Neutrophil Maturation and Recirculation Acting on the CXCR4/CXCL12 Pathway.

Neutrophil production and traffic in the body compartments is finely controlled, and the strong evidences support the role of CXCL12/CXCR4 pathway on neutrophil trafficking to and from the bone marrow (BM). We recently showed that the glucocorticoid-regulated protein, Annexin A1 (AnxA1) modulates neutrophil homeostasis and here we address the effects of AnxA1 on steady-state neutrophil maturation and trafficking. For this purpose, AnxA1(-/-) and Balb/C wild-type mice (WT) were donors of BM granulocytes and mesenchymal stem cells and blood neutrophils. In vivo treatments with the pharmacological AnxA1 mimetic peptide (Ac2-26) or the formyl peptide receptor (FPR) antagonist (Boc-2) were used to elucidate the pathway of AnxA1 action, and with the cytosolic glucocorticoid antagonist receptor RU 38486. Accelerated maturation of BM granulocytes was detected in AnxA1(-/-) and Boc2-treated WT mice, and was reversed by treatment with Ac2-26 in AnxA1(-/-) mice. AnxA1 and FPR2 were constitutively expressed in bone marrow granulocytes, and their expressions were reduced by treatment with RU38486. Higher numbers of CXCR4(+) neutrophils were detected in the circulation of AnxA1(-/-) or Boc2-treated WT mice, and values were rescued in Ac2-26-treated AnxA1(-/-) mice. Although circulating neutrophils of AnxA1(-/-) animals were CXCR4(+) , they presented reduced CXCL12-induced chemotaxis. Moreover, levels of CXCL12 were reduced in the bone marrow perfusate and in the mesenchymal stem cell supernatant from AnxA1(-/-) mice, and in vivo and in vitro CXCL12 expression was re-established after Ac2-26 treatment. Collectively, these data highlight AnxA1 as a novel determinant of neutrophil maturation and the mechanisms behind blood neutrophil homing to BM via the CXCL12/CXCR4 pathway. J. Cell. Physiol. 231: 2418-2427, 2016. © 2016 Wiley Periodicals, Inc.

The effects of protein malnutrition on the TNF-RI and NF-κB expression via the TNF-α signaling pathway.

Malnutrition is a nutritional condition that can affect many aspects of the immunological response, including by decreasing cell migration and stimulating phagocytosis; the bactericidal response; changes in reactive oxygen and nitrogen species production; and the production of proinflammatory cytokines, such as tumor necrosis factor alpha (TNF-α). This cytokine is primarily produced by macrophages and is associated with a wide range of biological activities, including inflammatory processes, growth, differentiation, and apoptosis. TNF-α acts through the activation of TNF receptors, and mainly receptor I (TNF-RI), which is responsible for most of the effects of TNF-α. This activation triggers a series of intracellular events that result in the activation of the transcription factor NF-κB. In this study, we evaluated the expression of the transcription factor NF-κB, mediated by TNF-α through TNF-RI, in a protein malnutrition (PM) model. Adult male BALB/c mice were submitted to PM, and after loss of approximately 20% of their body weight, their peritoneal macrophages were collected and cultivated with or without TNF-α. The expression of TNF-RI and proteins in its signaling pathway (TRADD, TRAF, RIP, IKK, IKB-α, pIKB-α, NF-κB, and pNF-κB) were evaluated, as well as cytokine production (IL-1α, IL-1ß, IL-6, and IL-12). The compiled results highlight that the malnourished animals presented anemia, leukopenia, and decreased peritoneal cellularity. TNF-RI expression was reduced in the malnourished animals, and NF-κB phosphorylation was also reduced, in association with reduced production of IL-1ß and IL-12. In this study, we observed aspects related to the innate immune response, and the outcome data allowed us to conclude that nutritional status interferes with the macrophage activation and the response capabilities of these cells.

Yerba Mate (Ilex paraguariensis) modulates NF-kappaB pathway and AKT expression in the liver of rats fed on a high-fat diet.

To investigate the effect of Yerba Mate (YM) aqueous extract intake on the NF-kB pathway and AKT expression in the liver, muscle, and adipose tissue of rats submitted to a high-fat diet (HFD). Male Wistar rats were fed a control (CON) (n = 24) or a HFD (n = 24) for 12 weeks. Afterwards, rats received YM daily (1 g/kg body weight) for 4 weeks. Intake of YM aqueous extract reduced body weight gain (p < 0.05) and total blood cholesterol (p < 0.05) in the HFD group in comparison to the non-treated HFD group. HFD group demonstrated an increased glycemic response at 5 and 10 min after insulin injection. YM decreased the ratio between phosphorylated and total kinase inhibitor of κB (IKK), increased the ratio of phosphorylated to total form of protein kinase B (AKT) and reduced NF-κB phosphorylation in the liver of the HFD group. Our data suggest a beneficial role of YM in improving metabolic dysfunctions induced by HFD.

Reduced protein intake and aging affects the sustainment of hematopoiesis by impairing bone marrow mesenchymal stem cells.

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.

Effects of Branched-Chain Amino Acids on the Inflammatory Response Induced by LPS in Caco-2 Cells.

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.

Effects of grape juice intake on the cell migration properties in overweight women: Modulation mechanisms of cell migration in vitro by delphinidin-3-O-glucoside.

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.

Modulation of the nuclear factor-kappa B (NF-κB) signalling pathway by glutamine in peritoneal macrophages of a murine model of protein malnutrition.

BACKGROUND AND AIMS: Protein malnutrition affects resistance to infection by impairing the inflammatory response, modifying the function of effector cells, such as macrophages. Recent studies have revealed that glutamine-a non-essential amino acid, which could become conditionally essential in some situations like trauma, infection, post-surgery and sepsis-is able to modulate the synthesis of cytokines. The aim of this study was to evaluate the effect of glutamine on the expression of proteins involved in the nuclear factor-kappa B (NF-κB) signalling pathway of peritoneal macrophages from malnourished mice. METHODS: Two-month-old male Balb/c mice were submitted to protein-energy malnutrition (n = 10) with a low-protein diet containing 2 % protein, whereas control mice (n = 10) were fed a 12 % protein-containing diet. The haemogram and analysis of plasma glutamine and corticosterone were evaluated. Peritoneal macrophages were pre-treated in vitro with glutamine (0, 0.6, 2 and 10 mmol/L) for 24 h and then stimulated with 1.25 µg LPS for 30 min, and the synthesis of TNF-α and IL-1α and the expression of proteins related to the NF-κB pathway were evaluated. RESULTS: Malnourished animals had anaemia, leucopoenia, lower plasma glutamine and increased corticosterone levels. TNF-α production of macrophages stimulated with LPS was significantly lower in cells from malnourished animals when cultivated in supraphysiological (2 and 10 mmol/L) concentrations of glutamine. Further, glutamine has a dose-dependent effect on the activation of macrophages, in both groups, when stimulated with LPS, inducing a decrease in TNF-α and IL-1α production and negatively modulating the NF-κB signalling pathway. CONCLUSIONS: These data lead us to infer that the protein malnutrition state interferes with the activation of macrophages and that higher glutamine concentrations, in vitro, have the capacity to act negatively in the NF-κB signalling pathway.

The effect of mate tea (Ilex paraguariensis) on metabolic and inflammatory parameters in high-fat diet-fed Wistar rats.

This study investigated the effects of mate tea (Ilex paraguariensis) aqueous extract consumption on metabolic indicators and inflammatory response of peritoneal macrophages in rats fed a high-fat diet (HFD). Male Wistar rats were fed a control diet or a HFD for 12 weeks. At the end of this period, rats received, or not, daily doses of yerba maté for 4 weeks. The consumption of yerba maté promoted weight loss, attenuated the HFD-detrimental effects on adiposity and insulin sensitivity and decreased blood levels of the inflammatory biomarkers (p < 0.05). Concerning peritoneal macrophages, mate tea consumption decreased the production of interleukin (IL)-6, but did not influence the production of IL-1ß, tumour necrosis factor-α and nitric oxide; cytokine mRNA expression; or the activation of the nuclear factor-κB signalling pathway. In summary, the consumption of mate tea had no consistent effect in the inflammatory response of peritoneal macrophages, but reduced cardiometabolic risk markers.

A review of the role of zinc finger proteins on hematopoiesis.

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.

Zinc and aging: a narrative review of the effects on hematopoiesis and its link with diseases.

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.

Delphinidin-3-O-glucoside in vitro suppresses NF-κB and changes the secretome of mesenchymal stem cells affecting macrophage activation.

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.

Protein restriction impairs the response activation/responsivity of MAPK signaling pathway of hematopoietic stem cells.

Protein restriction (PR) leads to bone marrow hypoplasia with changes in stromal cellularity components of the extracellular matrix in hematopoietic stem cells (HSCs). However, the underlying signaling mechanisms are poorly understood. We hypothesize that PR impairs the HSC mitogen-activated protein kinase (MAPK) signaling pathway response activation. Our aim is to evaluate the activation of MAPK and interleukin-3 (IL-3) proteins in HSC to explain PR-induced bone marrow hypoplasia, which causes altered proliferation and differentiation. C57BL/6 male mice were subjected to a low-protein diet (2% protein) or normoproteic (12% protein). PKC, PLCγ2, CaMKII, AKT, STAT3/5, ERK1/2, JNK, and p38d phosphorylation were evaluated by flow cytometry, and GATA1/2, PU.1, C/EBPα, NF-E2, and Ikz-3 genes (mRNAs) assessed by quantitative real-time-polymerase chain reaction. Pathway proteins, such as PLCγ2, JAK2, STAT3/5, PKC, and RAS do not respond to the IL-3 stimulus in PR, leading to lower activation of ERK1/2 and Ca2+ signaling pathways, consequently lowering the production of hematopoietic transcription factors. Colony forming units granulocyte-macrophage and colony forming units macrophage formation are impaired in PR even after being stimulated with IL-3. Long-term hematopoietic stem cells, short-term hematopoietic stem cells, granulocyte myeloid progenitor, and megakaryocyte-erythroid progenitor cells were significantly reduced in PR animals. This study shows for the first time that activation of MAPK pathway key proteins in HSCs is impaired in cases of PR. Several pathway proteins, such as PLCγ2, JAK2, STAT3, PKC, and RAS do not respond to IL-3 stimulation, leading to lower activation of extracellular signal-regulated protein kinase 1/2 and consequently lower production of hematopoietic transcription factors GATA1/2, PU.1, C/EBPa, NF-E2, and Ikz3. These changes result in a reduction in colony-forming units, proliferation, and differentiation, leading to hypocellularity.

The interaction between aging and protein malnutrition modulates peritoneal macrophage function: An experimental study in male mice.

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.