Mesenchymal stem cells attenuate acute liver failure by promoting expansion of regulatory T cells in an indoleamine 2,3-dioxygenase-dependent manner

© 2020, University of Kragujevac, Faculty of Science. All rights reserved. The influence of mesenchymal stem cells (MSCs) on the phenotype and function of CD4+CD49b+FoxP3-regulatory cells has not been elucidated. We used Concanavalin A (ConA)-and α-galactosylceramide (α-GalCer)-induced acute liver injury to estimate the effects of MSCs on liver-infiltrating CD4+CD49b+FoxP3-regulatory cells. MSCs significantly reduced ConA-and α-GalCer-mediated liver injury in C57BL/6 mice, as demonstrated by biochemical tests, reduced influx of inflammatory CD4+ T cells, and increased presence of CD4+CD49b+FoxP3-regulatory cells in the injured livers. The number of CD4+CD49b+FoxP3-regulatory cells was also significantly increased in α-GalCer-treated mice that received MSC-derived condi-tioned medium (MSC-CM). The presence of 1-methyltryp-tophan, a specific inhibitor of indoleamine 2,3-dioxygenase (IDO), in MSC-CM completely abrogated the hepatopro-tective effect of MSCs and significantly decreased the total number of liver-infiltrated CD4+CD49b+FoxP3-regulatory cells, indicating the crucial importance of MSC-derived IDO for the expansion of CD4+CD49b+FoxP3-regulatory cells and the consequent MSC-dependent attenuation of acute liver injury

“Derived Multiple Allogeneic Protein Paracrine Signaling (d-MAPPS)” Enhances T Cell-Driven Immune Response to Murine Mammary Carcinoma

Breast cancer is considered refractory to immunotherapy. Accordingly, there is an urgent need for the therapeutic use of new immunostimulatory agents which would enhance antitumor immune response against breast cancer cells. “Derived Multiple Allogeneic Protein Paracrine Signaling (d-MAPPS)” is a biological product whose activity is based on chemokines and cytokines that modulate homing and phenotype of immune cells. d-MAPPS contains high concentration of dendritic cell (DC) and T cell-attracting chemokine CXCL16 and potent T cell-activating cytokine IL-27 which enhance DC:T cell cross-talk in inflamed tissues. Herewith, we used 4T1 murine model of breast cancer to analyze d-MAPPS-dependent enhancement of T cell-driven antitumor immunity. 4T1+d-MAPPS-treated mice showed delayed mammary tumor appearance compared to 4T1+saline-treated animals. d-MAPPS significantly reduced tumor weight and volume and improved survival of 4T1-treated mice. Significantly increased concentration of CXCL16, IL-27, IFN-γ, and IL-17 and decreased concentration of immunosuppressive TGF-β and IL-10 were measured in serum samples and tumor tissues of 4T1+d-MAPPS-treated mice. d-MAPPS enhanced production of IL-12 and increased expression of MHC class II and costimulatory molecules on tumor-infiltrated DC, significantly improving their antigen-presenting properties. d-MAPPS in CXCL16-dependent manner promoted recruitment of antitumorigenic IFN-γ/IL-17-producing CD4+Th1/Th17 cells and in IL-27-dependent manner induced expansion of tumoricidal CD178+granzyme B-expressing CD8+CTLs and inhibited generation of tolerogenic DC, IL-10, and TGF-β-producing FoxP3-expressing T regulatory cells. In summing up, d-MAPPS, in CXL16- and IL-27-dependent manner, enhanced T cell-driven antitumor immune response and suppressed breast cancer growth in experimental mice

Highly potent antioxidant Olea europaea L. leaf extract affects carotid and renal haemodynamics in experimental hypertension

Haemodynamic alterations in carotid and renal arteries are associated with the severity of target organ damage in patients with hypertension. Dietary habits, such as the Mediterranean diet, regulate blood pressure and oxidative stress, thus reduce the mortality rate due to cardiovascular diseases. In this study, our aim was to evaluate the reducing activity, antioxidant capacity and metal chelating ability of standardized Olea europaea L. leaf extract (OLE), and to test its (5, 25, 50 mg/kg) acute in vivo effects, as well as oleuropein’s (OP, 10 mg/kg) on oxidative stress, carotid, renal and systemic haemodynamic parameters (blood pressure, heart rate, cardiac output, peripheral resistance) in spontaneously hypertensive rats (SHR). OLE has a higher antioxidative capacity than BHT, higher reducing ability than vitamin C, and 23 times lower capacity for metal ion chelation than EDTA. All three doses of OLE, and OP, improved oxidative stress in SHR. OLE5 improved carotid and renal haemodynamics, without significant effects on systemic haemodynamics. Two different mechanisms of antihypertensive responses to OLE were observed, OLE25 was most effective in reducing cardiovascular risks by improving systemic and regional (carotid and renal) haemodynamics, peripheral and regional vascular resistance. OLE50 causes the improvement of blood pressure and cardiac performances, but tends to retain elevated vascular resistance, therefore, reducing the inflow of blood into the brain and kidneys of the SHR. The OP did not alter systemic or regional haemodynamics, suggesting others constituents responsible for changes of cardiac function, as well as carotid and renal haemodynamics in response to OLE50

Therapeutic efficacy of mesenchymal stem cells for cardiovascular diseases

Despite the improvements in pharmacological and surgical treatments, cardiovascular diseases (CVDs) are the number one cause of death worldwide. During the last two decades, the search for new therapies has been revolutionized with the growing knowledge of stem cell biology. Due to their huge differentiation capacity and paracrine effects, mesenchymal stem cells (MSCs) are a promising tool for the treatment of CVDs. The encouraging outcomes of preclinical studies using MSCs as a treatment for diseased myocardium have set the scene for worldwide clinical trials. In this review, we overview either complete or ongoing clinical trials using MSCs for the therapy of CVDs. In particular, we analyze the biological properties of MSCs, elucidate recent clinical findings and clinical trial phases of investigation, highlight clinical therapeutic effects of MSCs, and discuss challenges towards the clinical use of these cells in the therapy of CVDs

The Effects of Mesenchymal Stem Cells on Antimelanoma Immunity Depend on the Timing of Their Administration.

There is still a lively debate about whether mesenchymal stem cells (MSCs) promote or suppress antitumor immune response. Although several possible explanations have been proposed, including different numbers of injected and engrafted MSCs, heterogeneity in phenotype, and function of tumor cells, the exact molecular mechanisms responsible for opposite effects of MSCs in modulation of antitumor immunity are still unknown. Herewith, we used a B16F10 murine melanoma model to investigate whether timing of MSC administration in tumor-bearing mice was crucially important for their effects on antitumor immunity. MSCs, intravenously injected 24 h after melanoma induction (B16F10+MSC1d-treated mice), significantly enhanced natural killer (NK) and T cell-driven antitumor immunity, suppressed tumor growth, and improved survival of melanoma-bearing animals. Significantly higher plasma levels of antitumorigenic cytokines (TNF-α and IFN-γ), remarkably lower plasma levels of immunosuppressive cytokines (TGF-β and IL-10), and a significantly higher number of tumor-infiltrating, IFN-γ-producing, FasL- and granzyme B-expressing NK cells, IL-17-producing CD4+Th17 cells, IFN-γ- and TNF-α-producing CD4+Th1 cells, and CD8+cytotoxic T lymphocytes (CTLs) were observed in B16F10+MSC1d-treated mice. On the contrary, MSCs, injected 14 days after melanoma induction (B16F10+MSC14d-treated mice), promoted tumor growth by suppressing antigen-presenting properties of tumor-infiltrating dendritic cells (DCs) and macrophages and by reducing tumoricidal capacity of NK cells and T lymphocytes. Significantly higher plasma levels of TGF-β and IL-10, remarkably lower plasma levels of TNF-α and IFN-γ, and significantly reduced number of tumor-infiltrating, I-A-expressing, and IL-12-producing macrophages, CD80- and I-A-expressing DCs, granzyme B-expressing CTLs and NK cells, IFN-γ- and IL-17-producing CTLs, CD4+Th1, and Th17 cells were observed in B16F10+MSC14d-treated animals. In summing up, the timing of MSC administration into the tumor microenvironment was crucially important for MSC-dependent modulation of antimelanoma immunity. MSCs transplanted during the initial phase of melanoma growth exerted tumor-suppressive effect, while MSCs injected during the progressive stage of melanoma development suppressed antitumor immunity and enhanced tumor expansion

Molecular and Cellular Mechanisms Responsible for Beneficial Effects of Mesenchymal Stem Cell-Derived Product "Exo-d-MAPPS" in Attenuation of Chronic Airway Inflammation.

Mesenchymal stem cells (MSCs), due to their potential for differentiation into alveolar epithelial cells and their immunosuppressive characteristics, are considered a new therapeutic agent in cell-based therapy of inflammatory lung disorders, including chronic obstructive pulmonary disease (COPD). Since most of the MSC-mediated beneficent effects were the consequence of their paracrine action, herewith, we investigated the effects of a newly designed MSC-derived product "Exosome-derived Multiple Allogeneic Protein Paracrine Signaling (Exo-d-MAPPS)" in the attenuation of chronic airway inflammation by using an animal model of COPD (induced by chronic exposure to cigarette smoke (CS)) and clinical data obtained from Exo-d-MAPPS-treated COPD patients. Exo-d-MAPPS contains a high concentration of immunomodulatory factors which are capable of attenuating chronic airway inflammation, including soluble TNF receptors I and II, IL-1 receptor antagonist, and soluble receptor for advanced glycation end products. Accordingly, Exo-d-MAPPS significantly improved respiratory function, downregulated serum levels of inflammatory cytokines (TNF-α, IL-1β, IL-12, and IFN-γ), increased serum concentration of immunosuppressive IL-10, and attenuated chronic airway inflammation in CS-exposed mice. The cellular makeup of the lungs revealed that Exo-d-MAPPS treatment attenuated the production of inflammatory cytokines in lung-infiltrated macrophages, neutrophils, and natural killer and natural killer T cells and alleviated the antigen-presenting properties of lung-infiltrated macrophages and dendritic cells (DCs). Additionally, Exo-d-MAPPS promoted the expansion of immunosuppressive IL-10-producing alternatively activated macrophages, regulatory DCs, and CD4+FoxP3+T regulatory cells in inflamed lungs which resulted in the attenuation of chronic airway inflammation. In a similar manner, as it was observed in an animal model, Exo-d-MAPPS treatment significantly improved the pulmonary status and quality of life of COPD patients. Importantly, Exo-d-MAPPS was well tolerated since none of the 30 COPD patients reported any adverse effects after Exo-d-MAPPS administration. In summing up, we believe that Exo-d-MAPPS could be considered a potentially new therapeutic agent in the treatment of chronic inflammatory lung diseases whose efficacy should be further explored in large clinical trials

Utjecaj autohtonih bakterija mliječne kiseline na proteolizu, mikrostrukturu i senzorska svojstva niskomasnih UF sireva tijekom zrenja

The influence of commercial bacteria Lactococcus lactis ssp. lactis and Lactococcus lactis ssp. cremoris (cheese A) and combinations of autochthonous lactic acid bacteria (LAB) strains Lactobacillus paracasei ssp. paracasei 08, Lactococcus lactis ssp. cremoris 656, Lactococcus lactis ssp. lactis 653 (cheese B and C) on composition, proteolysis, microstructure and sensory properties of low fat cheeses during ripening was investigated. Low fat cast ultra-filtered (UF) cheeses were produced according to the defined production procedure by mixing UF milk protein powder, skim milk and cream. Significant influence of different LAB strains on composition, primary proteolysis and microstructure was not found. Cheeses made with autochthonous LAB showed a higher rate of secondary proteolysis, as well as higher flavour scores, and were more acceptable than control cheese.U radu je utvrđen utjecaj komercijalnih Lactococcus lactis ssp. lactis i Lactococcus lactis ssp. cremoris (sir A) i kombinacija autohtonih bakterija mliječne kiseline (BMK) Lactobacillus paracasei ssp. paracasei 08, Lactococcus lactis ssp. cremoris 656, Lactococcus lactis ssp. lactis 653 i (sir B i C) na sastav, proteolizu, mikrostrukturu i senzorska svojstva niskomasnih sireva tijekom zrenja. Niskomasni sirevi od ultrafiltriranog mlijeka (UF) proizvedeni su prema definiranom tehnološkom postupku proizvodnje miješanjem UF proteina mlijeka u prahu, obranog mlijeka i vrhnja. Nije utvrđen značajan utjecaj različitih BMK na sastav, primarnu proteolizu i mikrostrukturu. Sirevi sa autohtonim BMK odlikovali su se višim stupnjem sekundarne proteolize, kao i boljim senzorskim svojstvima u odnosu na kontrolni sir

Cigarette smoke attenuates mesenchymal stem cell-based suppression of immune cell-driven acute liver failure.

Detrimental effects of smoking on mesenchymal stem cell (MSC)-dependent immunosuppression and hepatoprotection are unknown. Herewith, by using α-galactosylceramide (α-GalCer)-induced liver injury, a well-established murine model of fulminant hepatitis, we examined molecular mechanisms which were responsible for negative effects of cigarette smoke on MSC-dependent immunomodulation. MSC which were grown in cigarette smoke-exposed medium (MSCWS-CM) obtained pro-inflammatory phenotype, were not able to optimally produce hepatoprotective and immunosuppressive cytokines (TGF-β, HGF, IL-10, NO, KYN), and secreted significantly higher amounts of inflammatory cytokines (IFN-γ, TNF-α, IL-17, IL-6) than MSC that were cultured in standard medium never exposed to cigarette smoke (MSCCM). In contrast to MSCCM, which efficiently attenuated α-GalCer-induced hepatitis, MSCWS-CM were not able to prevent hepatocyte injury and liver inflammation. MSCWS-CM had reduced capacity for the suppression of liver-infiltrated inflammatory macrophages, dendritic cells (DCs) and lymphocytes. Although significantly lower number of IL-12-producing macrophages and DCs, TNF-α, IFN-γ or IL-17-producing CD4+ and CD8+T lymphocytes, NK and NKT cells were noticed in the livers of α-GalCer+MSCCM-treated mice compared to α-GalCer+saline-treated animals, this phenomenon was not observed in α-GalCer-injured mice that received MSCWS-CM. MSCWS-CM could not induce expansion of anti-inflammatory IL-10-producing FoxP3+CD4+ and CD8+ T regulatory cells and were not able to create immunosuppressive microenvironment in the liver as MSCCM. Similarly as it was observed in mice, MSCWS-CM were not able to optimally inhibit production of inflammatory and hepatototoxic cytokines in activated human Th1/Th17 and NKT1/NKT17 cells, confirming the hypothesis that cigarette smoke significantly attenuates therapeutic potential of MSC in cell-based immunotherapy of inflammatory liver diseases