Hypoxia enhances ILC3 responses through HIF-1α-dependent mechanism.

Group 3 innate lymphoid cells (ILC3) have a prominent role in the maintenance of intestine mucosa homeostasis. The hypoxia-inducible factor (HIF) is an important modulator of immune cell activation and a key mechanism for cellular adaptation to oxygen deprivation. However, its role on ILC3 is not well known. In this study, we investigated how a hypoxic environment modulates ILC3 response and the subsequent participation of HIF-1 signaling in this process. We found increased proliferation and activation of intestinal ILC3 at low oxygen levels, a response that was phenocopied when HIF-1α was chemically stabilized and was reversed when HIF-1 was blocked. The increased activation of ILC3 relied on a HIF-1α-dependent transcriptional program, but not on mTOR-signaling or a switch to glycolysis. HIF-1α deficiency in RORyt compartment resulted in impaired IL-17 and IL-22 production by ILC3 in vivo, which reflected in a lower expression of their target genes in the intestinal epithelium and an increased susceptibility to Clostridiodes difficile infection. Taken together, our results show that HIF-1α activation in intestinal ILC3 is relevant for their functions in steady state and infectious conditions.

The interplay among gut microbiota, hypertension and kidney diseases: The role of short-chain fatty acids.

The bacteria community living in the gut maintains a symbiotic relationship with the host and its unbalance has been associated with progression of a wide range of intestinal and extra intestinal conditions. Hypertension and chronic kidney disease (CKD) are closely associated diseases with high incidence rates all over the world. Increasing data have supported the involvement of gut microbiome in the blood pressure regulation and the impairment of CKD prognosis. In hypertension, the reduced number of short-chain fatty acids (SCFAs) producing bacteria is associated with modifications in gut environment, involving reduction of the hypoxic gut profile and worsening of the microbial balance, leading to a loss of epithelial barrier integrity, development of gut inflammation and the reduction of SCFAs plasma levels. These modifications compromise the blood pressure regulation and, as a consequence, favor the end organ damage, also affecting the kidneys. In CKD, impaired renal function leads to accumulation of high levels of uremic toxins that reach the intestine and cause alterations in bacteria composition and fecal metabolite profile, inducing a positive feedback that allows translocation of endotoxins into the bloodstream, which enhances local kidney inflammation and exacerbate kidney injury, compromising even more CKD prognosis. In line with these data, the use of prebiotics, probiotics and fecal microbiota transplantation are becoming efficient therapies to improve the gut dysbiosis aiming hypertension and CKD treatment. This review describes how changes in gut microbiota composition can affect the development of hypertension and the progression of kidney diseases, highlighting the importance of the gut microbial composition uncovering to improve human health maintenance and, especially, for the development of new alternative therapies.

Co-transplantation of Xenogeneic Bone Marrow-derived Mesenchymal Stem Cells Alleviates Rejection of Pancreatic Islets in Non-obese Diabetic Mice.

Bone marrow-mesenchymal stem cells (BM-MSCs) have generated a great perspective in the field of regenerative medicine, and also in the treatment of inflammatory and autoimmune diseases in the past decade due to their immunomodulatory and anti-inflammatory properties. Here, we investigated the effect of xenogeneic BM-MSCs and pancreatic islets co-transplantation obtained from Wistar rats in preventing rejection or inducing tolerance to islet transplantation in non-obese diabetic mice. Non-obese diabetic mice were treated with co-transplantation of pancreatic islets and BM-MSCs (islet + MSCs group) or pancreatic islets only (islet group). Compared to the islet group, islet + MSCs had a lower expression of inflammatory markers, such as, tumor necrosis factor- α (13.40 ± 0.57 vs. 9.90 ± 0.12, P = .01), monocyte chemoattractant protein 1 (51.30 ± 6.80 vs. 9.00 ± 1.80, P = .01), and interleukin 1ß (IL-1ß) (16.2 ± 1.65 vs. 6.80 ± 1.00, P = .04). Comparing the expression of immune tolerance markers, it is noted that animals receiving the co-transplantation showed a significantly higher expression than the islet group of IL-4 (25.60 ± 1.96 vs. 2.80 ± 0.20, P = .004), IL-10 (188.40 ± 4.60 vs. 4.55 ± 0.12, P = .0001), and forkhead box P3 (34.20 ± 1.3 vs. 1.30 ± 0.2, P = .004), respectively. These results suggest an immunomodulatory action of BM-MSC in islet xenotransplantation showing that these stem cells have the potential to mitigate the early losses of grafts, due to the regulation of the inflammatory process of transplantation.

SOCS1 favors the epithelial-mesenchymal transition in melanoma, promotes tumor progression and prevents antitumor immunity by PD-L1 expression.

Silencing of SOCS1 protein with shRNAi lentivirus (shR-SOCS1) led to partial reversion of the tumorigenic phenotype of B16F10-Nex2 melanoma cells. SOCS1 silencing inhibited cell migration and invasion as well as in vitro growth by cell cycle arrest at S phase with increased cell size and nuclei. Down-regulation of SOCS1 decreased the expression of epidermal growth factor receptor, Ins-Rα, and fibroblast growth factor receptors. The present work aimed at analyzing the SOCS1 cell signaling and expression of proteins relevant to tumor development. An RNA microarray analysis of B16F10-Nex2 melanoma cells with SOCS1 silenced by shRNAi-SOCS1 was undertaken in comparison with cells transduced with the empty vector. Among 609 differentially expressed genes, c-Kit, Met and EphA3 cytokine/tyrosine-kinase (TK) receptors were down regulated. A significant decrease in the expression of TK receptors, the phosphorylation of mediators of ERK1/2 and p38 pathways and STAT3 (S727) were observed. Subcutaneous immunization with shR-SOCS1-transduced viable tumor cells rendered protection against melanoma in a syngeneic model, with decreased expression of PD-L1 and of matrix metallo-proteinases (MMPs) and CD-10 in those cells. The present work shows the role of SOCS1 in murine melanoma development and the potential of SOCS1-silenced tumor cells in raising an effective anti-melanoma immune response.

Follicular helper T cell in immunity and autoimmunity.

The traditional concept that effector T helper (Th) responses are mediated by Th1/Th2 cell subtypes has been broadened by the recent demonstration of two new effector T helper cells, the IL-17 producing cells (Th17) and the follicular helper T cells (Tfh). These new subsets have many features in common, such as the ability to produce IL-21 and to express the IL-23 receptor (IL23R), the inducible co-stimulatory molecule ICOS, and the transcription factor c-Maf, all of them essential for expansion and establishment of the final pool of both subsets. Tfh cells differ from Th17 by their ability to home to B cell areas in secondary lymphoid tissue through interactions mediated by the chemokine receptor CXCR5 and its ligand CXCL13. These CXCR5+ CD4+ T cells are considered an effector T cell type specialized in B cell help, with a transcriptional profile distinct from Th1 and Th2 cells. The role of Tfh cells and its primary product, IL-21, on B-cell activation and differentiation is essential for humoral immunity against infectious agents. However, when deregulated, Tfh cells could represent an important mechanism contributing to exacerbated humoral response and autoantibody production in autoimmune diseases. This review highlights the importance of Tfh cells by focusing on their biology and differentiation processes in the context of normal immune response to infectious microorganisms and their role in the pathogenesis of autoimmune diseases.

Effects of acute aerobic exercise on leukocyte inflammatory gene expression in systemic lupus erythematosus.

UNLABELLED: Systemic lupus erythematosus (SLE) is an autoimmune disease with a persistent systemic inflammation. Exercise induced inflammatory response in SLE remains to be fully elucidated. The aim of this study was to assess the effects of acuteexercise on leukocyte gene expression in active (SLEACTIVE) and inactive SLE (SLEINACTIVE) patients and healthy controls(HC). METHODS: All subjects (n = 4 per group) performed a 30-min single bout of acute aerobic exercise (~70% of VO2peak) on a treadmill, and blood samples were collected for RNA extraction from circulating leukocyte at baseline, at the end of exercise, and after three hours of recovery. The expression of a panel of immune-related genes was evaluated by a quantitative PCR array assay. Moreover, network-based analyses were performed to interpret transcriptional changes occurring after the exercise challenge. RESULTS: In all groups, a single bout of acute exercise led to the down-regulation of the gene expression of innate and adaptive immunity at the end of exercise (e.g., TLR3, IFNG, GATA3, FOXP3, STAT4) with a subsequent up-regulation occurring upon recovery. Exercise regulated the expression of inflammatory genes in the blood leukocytes of the SLE patients and HC, although the SLE groups exhibited fewer modulated genes and less densely connected networks (number of nodes: 29, 40 and 58; number of edges: 29, 60 and 195; network density: 0.07, 0.08 and 0.12, for SLEACTIVE, SLEINACTIVE and HC, respectively). CONCLUSION: The leukocytes from the SLE patients, irrespective of disease activity, showed a down-regulated inflammatory geneexpression immediately after acute aerobic exercise, followed by an up-regulation at recovery. Furthermore, less organized gene networks were observed in the SLE patients, suggesting that they may be deficient in triggering a normal exercised-induced immune transcriptional response.

Follicular helper T cell in immunity and autoimmunity

The traditional concept that effector T helper (Th) responses are mediated by Th1/Th2 cell subtypes has been broadened by the recent demonstration of two new effector T helper cells, the IL-17 producing cells (Th17) and the follicular helper T cells (Tfh). These new subsets have many features in common, such as the ability to produce IL-21 and to express the IL-23 receptor (IL23R), the inducible co-stimulatory molecule ICOS, and the transcription factor c-Maf, all of them essential for expansion and establishment of the final pool of both subsets. Tfh cells differ from Th17 by their ability to home to B cell areas in secondary lymphoid tissue through interactions mediated by the chemokine receptor CXCR5 and its ligand CXCL13. These CXCR5+ CD4+ T cells are considered an effector T cell type specialized in B cell help, with a transcriptional profile distinct from Th1 and Th2 cells. The role of Tfh cells and its primary product, IL-21, on B-cell activation and differentiation is essential for humoral immunity against infectious agents. However, when deregulated, Tfh cells could represent an important mechanism contributing to exacerbated humoral response and autoantibody production in autoimmune diseases. This review highlights the importance of Tfh cells by focusing on their biology and differentiation processes in the context of normal immune response to infectious microorganisms and their role in the pathogenesis of autoimmune diseases.

Inflammatory cytokine kinetics to single bouts of acute moderate and intense aerobic exercise in women with active and inactive systemic lupus erythematosus.

The aim of this study was to evaluate changes in the cytokines INF-γ, IL-10, IL-6, TNF-α and soluble TNF receptors (sTNFR1 and sTNFR2) in response to single bouts of acute moderate and intense exercise in systemic lupus erythematosus women with active (SLE(ACTIVE)) and inactive (SLE(INACTIVE)) disease. Twelve SLE(INACTIVE) women (age: 35.3 ± 5.7 yrs; BMI: 25.6±3.4 kg/m2), eleven SLE(ACTIVE) women (age: 30.4 ± 4.5 yrs; BMI: 26.1±4.8 kg/m2), and 10 age- and BMI-matched healthy control women (HC) performed 30 minutes of acute moderate (~50% of VO(2)peak) and intense (~70% of VO(2)peak) exercise bout. Cytokines and soluble TNF receptors were assessed at baseline, immediately after, every 30 minutes up to three hours, and 24 hours after both acute exercise bouts. In response to acute moderate exercise, cytokines and soluble TNF receptors levels remained unchanged in all groups (P>0.05), except for a reduction in IL-6 levels in the SLE(ACTIVE) group at the 60th and 180th minutes of recovery (P<0.05), and a reduction in sTNFR1 levels in the HC group at the 90th, 120th, 150th, 180th minutes of recovery (P<0.05). The SLE(INACTIVE) group showed higher levels of TNF-α, sTNFR1, and sTNFR2 at all time points when compared with the HC group (P<0.05). Also, the SLE(ACTIVE) group showed higher levels of IL-6 at the 60th minute of recovery (P<0.05) when compared with the HC group. After intense exercise, sTNFR1 levels were reduced at the 150th (P=0.041) and 180th (P=0.034) minutes of recovery in the SLE(INACTIVE) group, whereas the other cytokines and sTNFR2 levels remained unchanged (P>0.05). In the HC group, IL-10, TNF-α, sTNFR1, and sTNFR2 levels did not change, whilst INF-γ levels decreased (P=0.05) and IL-6 levels increased immediately after the exercise (P=0.028), returning to baseline levels 24 hours later (P > 0.05). When compared with the HC group, the SLE(INACTIVE) group showed higher levels of TNF-α and sTNFR2 in all time points, and higher levels of sTNFR1 at the end of exercise and at the 30th minute of recovery (P<0.05). The SLE(ACTIVE) group also showed higher levels of TNF-α at all time points when compared with the HC group (P<0.05), (except after 90 min, 120 min and 24 hours of recovery) (P>0.05). Importantly, the levels of all cytokine and soluble TNF receptors returned to baseline 24 hours after the end of acute exercise, irrespective of its intensity, in all three groups (P>0.05). This study demonstrated that both the single bouts of acute moderate and intense exercise induced mild and transient changes in cytokine levels in both SLE(INACTIVE) and SLE(ACTIVE) women, providing novel evidence that acute aerobic exercise does not trigger inflammation in patients with this disease.

Impaired structural and functional regeneration of skeletal muscles from ß2-adrenoceptor knockout mice.

AIMS: ß2-adrenergic stimulation causes beneficial effects on structure and function of regenerating muscles; thus, the ß2-adrenoceptor may play an important role in the muscle regenerative process. Here, we investigated the role of the ß2 -adrenoceptor in skeletal muscle regeneration. METHODS: Tibialis anterior (TA) muscles from ß2-adrenoceptor knockout (ß2 KO) mice were cryolesioned and analysed after 1, 3, 10 and 21 days. The role of ß2-adrenoceptor on regenerating muscles was assessed through the analysis of morphological and contractile aspects, M1 and M2 macrophage profile, cAMP content, and activation of TGF-ß signalling elements. RESULTS: Regenerating muscles from ß2 KO mice showed decreased calibre of regenerating myofibres and reduced muscle contractile function at 10 days when compared with those from wild type. The increase in cAMP content in muscles at 10 days post-cryolesion was attenuated in the absence of the ß2 -adrenoceptor. Furthermore, there was an increase in inflammation and in the number of macrophages in regenerating muscles lacking the ß2-adrenoceptor at 3 and 10 days, a predominance of M1 macrophage phenotype, a decrease in TßR-I/Smad2/3 activation, and in the Smad4 expression at 3 days, while akirin1 expression increased at 10 days in muscles from ß2 KO mice when compared to those from wild type. CONCLUSIONS: Our results suggest that the ß2-adrenoceptor contributes to the regulation of the initial phases of muscle regeneration, especially in the control of macrophage recruitment in regenerating muscle through activation of TßR-I/Smad2/3 and reduction in akirin1 expression. These findings have implications for the future development of better therapeutic approaches to prevent or treat muscle injuries.

Flavonone treatment reverses airway inflammation and remodelling in an asthma murine model.

BACKGROUND AND PURPOSE: Asthma is an inflammatory disease that involves airway hyperresponsiveness and remodelling. Flavonoids have been associated to anti-inflammatory and antioxidant activities and may represent a potential therapeutic treatment of asthma. Our aim was to evaluate the effects of the sakuranetin treatment in several aspects of experimental asthma model in mice. EXPERIMENTAL APPROACH: Male BALB/c mice received ovalbumin (i.p.) on days 0 and 14, and were challenged with aerolized ovalbumin 1% on days 24, 26 and 28. Ovalbumin-sensitized animals received vehicle (saline and dimethyl sulfoxide, DMSO), sakuranetin (20 mg kg(-1) per mice) or dexamethasone (5 mg kg(-1) per mice) daily beginning from 24th to 29th day. Control group received saline inhalation and nasal drop vehicle. On day 29, we determined the airway hyperresponsiveness, inflammation and remodelling as well as specific IgE antibody. RANTES, IL-5, IL-4, Eotaxin, IL-10, TNF-α, IFN-γ and GMC-SF content in lung homogenate was performed by Bioplex assay, and 8-isoprostane and NF-kB activations were visualized in inflammatory cells by immunohistochemistry. KEY RESULTS: We have demonstrated that sakuranetin treatment attenuated airway hyperresponsiveness, inflammation and remodelling; and these effects could be attributed to Th2 pro-inflammatory cytokines and oxidative stress reduction as well as control of NF-kB activation. CONCLUSIONS AND IMPLICATIONS: These results highlighted the importance of counteracting oxidative stress by flavonoids in this asthma model and suggest sakuranetin as a potential candidate for studies of treatment of asthma.

Leptin deficiency modulates allograft survival by favoring a Th2 and a regulatory immune profile. [corrected].

Leptin, an adipose-secreted hormone, links metabolism and immunity. Our aim was to determine whether leptin affects the alloimmune response. We used an allogeneic skin transplant model as a means to analyze the allograft immune response in Lep(ob/ob) and wild-type mice. Leptin deficiency results in an increased frequency of Treg and Th2 cells and a prolonged graft survival. These effects of leptin deficiency indicate the importance of leptin and obesity in modulating the allograft immune responses. Our data suggest a possible explanation for the increased susceptibility of hyperleptinemic obese patients to acute and chronic graft rejection.

Comparison of long-term effect of thymoglobulin treatment in patients with a high risk of delayed graft function.

BACKGROUND: T-lymphocyte depletion is a strategy to reverse the impact of ischemia-reperfusion injury (IRI) in progression to chronic allograft dysfunction, especially among patients at high risk for delayed graft function (DGF). METHODS: The present work assessed the effect of thymoglobulin among a population with a high incidence of DGF. We analyzed 209 transplanted patients: 97 in the thymoglobulin and 112 in the control group. RESULTS: The main complication was DGF (59.3%), with a similar incidence in both groups (63.9% vs. 55.3%; P = .36). Acute rejection episodes (ARE) were decreased with thymoglobulin (8.2% vs. 28.5%; P < .001), but cytomegalovirus viremia was 3.4-fold more frequent (58.3% vs. 17.1%; P < .001). One-year graft function was significantly better in the thymoglobulin group (59.2 ± 17.2 vs. 51.8 ± 15.3 mL/min; P = .004), even when censored by ARE (59.7 ± 17.5 vs. 53.3 ± 14.4; P = .023). The same difference was observed at the 2-year follow-up (P = .024), even when censored for ARE (P = .045). A multivariate analysis showed thymoglobulin to be a factor strongly associated with protection of graft function (P = .039). CONCLUSION: Despite not reducing the incidence of DGF, thymoglobulin induction significantly reduced the incidence of ARE and showed a long-term profile of protection of renal graft function, independent of the reduction in ARE.

Expression of pancreatic endocrine markers by mesenchymal stem cells from human adipose tissue.

Mesenchymal stem cells (MSCs) from human adipose tissue have a great potential for use in cell therapy due to their ease of isolation, expansion, and differentiation, besides the relative acceptance from the ethical point of view. Our intention was to isolate and promote in vitro expansion and differentiation of MSCs from human adipose tissue into cells with a pancreatic endocrine phenotype. Human adipose tissue obtained from patients undergoing abdominal dermolipectomy was digested with type I collagenase. MSCs isolated by plastic adherence and characterized by cytochemistry and FACS were expanded in vitro. MSC differentiation into an endocrine phenotype was induced over 2 to 4 months with high glucose (25 mmol/L) media containing nicotinamide, exendin-4, and 2-mercaptoethanol. Insulin and glucagon expressions were analyzed by immunofluorescence. Cells isolated from human adipose tissue and expanded in vitro expressed MSC markers as confirmed by FACS and cytochemistry. Insulin but not glucagon production by differentiated cells was demonstrated by immunofluorescence. MSCs isolated from human adipose tissue were induced to differentiate in vitro into an endocrine phenotype that expressed insulin.

Leptin as a link between the immune system and kidney-related diseases: leading actor or just a coadjuvant?

Food intake and nutritional status modify the physiological responses of the immune system to illness and infection and regulate the development of chronic inflammatory processes, such as kidney disease. Adipose tissue secretes immune-related proteins called adipokines that have pleiotropic effects on both the immune and neuroendocrine systems, linking metabolism and immune physiology. Leptin, an adipose tissue-derived adipokine, displays a variety of immune and physiological functions, and participates in several immune responses. Here, we review the current literature on the role of leptin in kidney diseases, linking adipose tissue and the immune system with kidney-related disorders. The modulation of this adipose hormone may have a major impact on the treatment of several immune- and metabolic-related kidney diseases.

Prevalence and progression of chronic kidney disease after renal transplantation.

BACKGROUND: We studied the prevalence of chronic kidney disease (CKD) and its progression after kidney transplantation. METHODS: We retrospectively analyzed the evolution of renal graft function, as estimated by the Cockcroft-Gault equation in 567 patients. CKD was classified in accordance with the National Kidney Foundation/Kidney Disease Outcome Quality Initiative with progression estimated by calculating the slope over time. RESULTS: Creatinine clearance (CrCL) at 1 year after transplantation was 57.8 ± 15.5 mL/min with 61.9% patients presenting de novo chronic renal failure. The 1-year-CrCl provided the best correlation with the 3-year CrCl (R(2) = 0.58; P < .001). Medians of slope (MS) among all patients was -2.38 ± 5.7 mL/min/y (-11.9 mL/min over 5 years). Patients who reached a CrCl < 60 at 1 year after transplantation showed a MS of -3.92 ± 6.5, while the others, -2.03 ± 5.2 mL/min/y (P = .046). Similarly, patients who reached a CrCL < 60 at 3 years after transplantation displayed a MS of -1.49 ± 3.5 mL/min/y, while the others, 0.62 ± 3.0 mL/min/y (P < .001). CONCLUSIONS: The majority of renal transplant patients present de novo chronic renal failure already at 1 year posttransplantation. The rate of graft functional deterioration was 2.38 mL/min/y. It was worse among patients who displayed a CrCL less than 60 mL/min both at 1 and at 3 years. One-year CrCL was a good marker for 3-year CrCL.

Effects of ischemia and reperfusion injury on long-term graft function.

BACKGROUND: The clinical manifestation of ischemia/reperfusion injury in renal transplantation is delayed graft function (DGF), which is associated with an increase in acute rejection episodes (ARE), costs, and difficulties in immunosuppressive management. We sought to evaluated the DGF impact after renal transplant. METHODS: We evaluated a group of 628 patients undergoing deceased donor renal transplantation between 2002 and 2005 at 3 Brazilians institutions to define the main DGF characteristics. RESULTS: DGF incidence was 56.8%, being associated with elderly donors (P = .02), longer time on dialysis (P = .001), and greater cold ischemia time (CIT; P = .001). Upon multivariate analysis, time on dialysis >5 years increased DGF risk by 42% (P = .02) and CIT >24 hours increased it by 57% (P = .008). In contrast, DGF was associated with an higher incidence of ARE: 27.7% in DGF versus 18.4% in IGF patients (P = .047). The ARE risk was 46% higher among individuals with DGF (P = .02), 44% among patients >45 years old (P < .001), 50% among those with >5 years of dialysis time (P = .02), and 47% lower among the who were prescribed mycophenolate instead of azathioprine (P < .001). Patients with DGF showed worse 1-year graft function (54.6 ± 20.3 vs 59.6 ± 19.4 mL/min; P = .004), particularly those with ARE (55.5 ± 19.3 vs 60.7 ± 20.4; P = .009). One-year graft survival was 88.5% among DGF versus 94.0% among non-DGF patients. CONCLUSION: The high incidence of DGF was mainly associated with a prolonged CIT. There was a relationship between DGF and ARE, as well as with a negative influence on long-term graft function.