C.S. Barrios

Immunomodulatory effects of curcumin in allergy

Recent years have witnessed a global increase in allergy and asthma, particularly in developed countries. Attempts to develop effective control measures for allergy and asthma resulted in the exploration of alternate medicines including herbal remedies traditionally used in old world countries. Turmeric is known for its multiple health restoring properties, and has been used in treating several diseases including several respiratory disorders. Turmeric is a common spice used in the culinary preparations in South and East Asian countries. The active component of turmeric is curcumin, a polyphenolic phytochemical, with anti-inflammatory, antiamyloid, antiseptic, antitumor, and antioxidative properties. Curcumin was reported to have antiallergic properties with inhibitory effect on histamine release from mast cells. The effectiveness of curcumin in allergy and asthma has been further investigated using a murine model of allergy. The results indicate a marked inhibition of allergic response in animals treated with curcumin suggesting a major role for curcumin in reducing the allergic response. The present review focuses on the results of research aimed to understand the immunomodulation induced by curcumin and its associated roles in the amelioration of allergy. These findings needed further evaluation, extrapolation, and confirmation before using curcumin for controlling allergy and asthma in humans.

Immune response modulation by curcumin in a latex allergy model

BackgroundThere has been a worldwide increase in allergy and asthma over the last few decades, particularly in industrially developed nations. This resulted in a renewed interest to understand the pathogenesis of allergy in recent years. The progress made in the pathogenesis of allergic disease has led to the exploration of novel alternative therapies, which include herbal medicines as well. Curcumin, present in turmeric, a frequently used spice in Asia has been shown to have anti-allergic and inflammatory potential.MethodsWe used a murine model of latex allergy to investigate the role of curcumin as an immunomodulator. BALB/c mice were exposed to latex allergens and developed latex allergy with a Th2 type of immune response. These animals were treated with curcumin and the immunological and inflammatory responses were evaluated.ResultsAnimals exposed to latex showed enhanced serum IgE, latex specific IgG1, IL-4, IL-5, IL-13, eosinophils and inflammation in the lungs. Intragastric treatment of latex-sensitized mice with curcumin demonstrated a diminished Th2 response with a concurrent reduction in lung inflammation. Eosinophilia in curcumin-treated mice was markedly reduced, co-stimulatory molecule expression (CD80, CD86, and OX40L) on antigen-presenting cells was decreased, and expression of MMP-9, OAT, and TSLP genes was also attenuated.ConclusionThese results suggest that curcumin has potential therapeutic value for controlling allergic responses resulting from exposure to allergens.

Mitochondria-Targeted Analogues of Metformin Exhibit Enhanced Antiproliferative and Radiosensitizing Effects in Pancreatic Cancer Cells

Metformin (Met) is an approved antidiabetic drug currently being explored for repurposing in cancer treatment based on recent evidence of its apparent chemopreventive properties. Met is weakly cationic and targets the mitochondria to induce cytotoxic effects in tumor cells, albeit not very effectively. We hypothesized that increasing its mitochondria-targeting potential by attaching a positively charged lipophilic substituent would enhance the antitumor activity of Met. In pursuit of this question, we synthesized a set of mitochondria-targeted Met analogues (Mito-Mets) with varying alkyl chain lengths containing a triphenylphosphonium cation (TPP(+)). In particular, the analogue Mito-Met10, synthesized by attaching TPP(+) to Met via a 10-carbon aliphatic side chain, was nearly 1,000 times more efficacious than Met at inhibiting cell proliferation in pancreatic ductal adenocarcinoma (PDAC). Notably, in PDAC cells, Mito-Met10 potently inhibited mitochondrial complex I, stimulating superoxide and AMPK activation, but had no effect in nontransformed control cells. Moreover, Mito-Met10 potently triggered G1 cell-cycle phase arrest in PDAC cells, enhanced their radiosensitivity, and more potently abrogated PDAC growth in preclinical mouse models, compared with Met. Collectively, our findings show how improving the mitochondrial targeting of Met enhances its anticancer activities, including aggressive cancers like PDAC in great need of more effective therapeutic options. Cancer Res; 76(13); 3904-15. ©2016 AACR.

Recombinant human T-cell leukemia virus types 1 and 2 Tax proteins induce high levels of CC-chemokines and downregulate CCR5 in human peripheral blood mononuclear cells

Human T-cell leukemia viruses types 1 (HTLV-1) and 2 (HTLV-2) produce key transcriptional regulatory gene products, known as Tax1 and Tax2, respectively. Tax1 and Tax2 transactivate multiple host genes involved in cellular immune responses within the cellular microenvironment, including induction of genes encoding expression of CC-chemokines. It is speculated that HTLV Tax proteins may act as immune modulators. In this study, recombinant Tax1 and Tax2 proteins were tested for their effects on the viability of cultured peripheral blood mononuclear cells (PBMCs), and their ability to induce expression of CC-chemokines and to downregulate the level of CCR5 expression in PBMCs. PBMCs obtained from uninfected donors were cultured in a range of Tax1 and Tax2 concentrations (10-100 pM), and supernatant fluids were harvested at multiple time points for quantitative determinations of MIP-1α/CCL3, MIP-1β/CCL4, and RANTES/CCL5. Treatment of PBMCs with Tax1 and Tax2 proteins (100 pM) resulted in a significant increase in viability over a 7-d period compared to controls (p<0.01). Both Tax1 and Tax2 induced high levels of all three CC-chemokines over the dosing range compared to mock-treated controls (p<0.05). The gated population of lymphocytes treated with Tax2, as well as lymphocytes from HTLV-2-infected donors, showed a significantly lower percentage of CCR5-positive cells compared to those of uninfected donors and from mock-treated lymphocytes, respectively (p<0.05). These results suggest that Tax1 and Tax2 could promote innate immunity in the extracellular environment during HTLV-1 and HTLV-2 infections via CC-chemokine ligands and receptors.

The costimulatory molecules CD80, CD86 and OX40l are up-regulated in Aspergillus fumigatus sensitized mice

Aspergillus fumigatus (Af) is a fungus associated with allergic bronchopulmonary aspergillosis (ABPA) and other allergic diseases. Immune responses in these diseases are due to T and B cell responses. T cell activation requires both Af‐specific engagement of the T‐cell‐receptor as well as interaction of antigen independent costimulatory molecules including CD28‐CD80/CD86 and OX40–OX40L interactions. Since these molecules and their interactions have been suggested to have a potential involvement in the pathogenesis of ABPA, we have investigated their role in a model of experimental allergic aspergillosis. BALB/c mice were primed and sensitized with Af allergens, with or without exogenous IL‐4. Results showed up‐regulation of both CD86 and CD80 molecules on lung B cells from Af‐sensitized mice (79% CD86+ and 24% CD80+) and Af/rIL‐4‐treated mice (90% CD86+ and 24% CD80+) compared to normal controls (36% and 17%, respectively). Lung macrophages in Af‐sensitized mice treated or not with IL‐4 showed enhanced expression of these molecules. OX40L expression was also up‐regulated on lung B cells and macrophages from both Af‐sensitized and Af/rIL‐4 exposed mice as compared to normal controls. All Af‐sensitized animals showed peripheral blood eosinophilia, enhanced total serum IgE and allergen‐specific IgG1 antibodies and characteristic lung inflammation. The up‐regulation of CD80, CD86 and OX40L molecules on lung B cells and macrophages from Af‐allergen exposed mice suggests a major role for these molecules in the amplification and persistence of immunological and inflammatory responses in ABPA.

Immune Response among Patients Exposed to Molds

Macrocyclic trichothecenes, mycotoxins produced by Stachybotrys chartarum, have been implicated in adverse reactions in individuals exposed to mold-contaminated environments. Cellular and humoral immune responses and the presence of trichothecenes were evaluated in patients with mold-related health complaints. Patients underwent history, physical examination, skin prick/puncture tests with mold extracts, immunological evaluations and their sera were analyzed for trichothecenes. T-cell proliferation, macrocyclic trichothecenes, and mold specific IgG and IgA levels were not significantly different than controls; however 70% of the patients had positive skin tests to molds. Thus, IgE mediated or other non-immune mechanisms could be the cause of their symptoms.

Induction of CC-chemokines with antiviral function in macrophages by the human T lymphotropic virus type 2 transactivating protein, Tax2.

Recent data provide evidence that co-infection with human immunodeficiency virus type 1 (HIV-1) and human T lymphotropic virus type 2 (HTLV-2) delays progression to AIDS compared to isolated HIV-1 infection. These results were linked to expression of the HTLV-2 transcriptional activating gene known as Tax2. Preliminary studies in lymphocytic systems suggest that Tax2 is responsible for induction of CC-chemokines, which play a major role in innate immune responses against HIV-1. In this study, the effect of Tax2 on CC-chemokines (MIP-1α/CCL3, MIP-1β/CCL4, and RANTES/CCL5) in monocyte-derived macrophages (MDMs) was evaluated. An immortalized human monocytic cell line (U937) and donor-derived MDMs were used to evaluate these interactions. These cells were cultured in vitro, allowed to mature into macrophages for 14 d, and treated with Tax2 or Tax1 (the transcriptional activator of HTLV-1) at three concentrations (1, 10, and 100 pM) daily thereafter. Extracellular bacterial extract (EBE) lacking the vector and untreated samples served as controls. An additional group of donor-derived MDMs were transduced with an adenovirus vector that expressed either Tax2 or green fluorescent protein (GFP). Liposomal transfection agents alone were used as controls. Supernatants were collected from each sample on multiple days post-maturation and evaluated for MIP-1α, MIP-1β, and RANTES, by enzyme-linked immunosorbent assay. Analysis of variance and Tukeys Honestly Significant Difference tests were used to analyze the results. In all systems, cells exposed to either Tax2 or Tax1 expressed significantly (p<0.01) higher concentrations of CC-chemokines than controls. There was no significant difference in chemokine expression between Tax1-treated and Tax2-treated samples, between EBE-treated and EBE-untreated samples, or between GFP-transduced MDMs and controls. This suggests that HTLV-2 could alter innate immune responses in macrophagic reservoirs of HIV-1 in HIV-1/HTLV-2 co-infected individuals, and could guide the development of HIV-1 treatments.

High levels of CC‐chemokine expression and downregulated levels of CCR5 during HIV‐1/HTLV‐1 and HIV‐1/HTLV‐2 coinfections

The human T‐cell lymphotropic virus type 1 (HTLV‐1) and HTLV‐2 are common copathogens among Human Immunodeficiency Virus (HIV)‐infected individuals. HTLV‐2 may confer a survival benefit among patients with HIV‐1/HTLV‐2 coinfections, along with lower plasma HIV‐1 levels and delayed rates of CD4+ T‐cell decline. These effects have been attributed to the ability of the HTLV‐2 viral transactivating Tax2 protein to induce the production of high levels of antiviral CC‐chemokines and to downregulate expression of the CCR5 receptor, resulting in impaired entry of HIV‐1 into CD4+ T‐cells. This study investigated the innate immunity of coinfected HIV/HTLV individuals by testing the ability of patient PBMCs to produce CC‐chemokines in association CCR5 receptor modulation. The cellular proliferative responses of HIV/HTLV coinfected versus HIV monoinfected individuals were also evaluated. Higher levels of MIP‐1α, MIP‐1β, and RANTES (P < 0.05) were found in HIV‐1/HTLV‐2 coinfected group compared to HIV‐1 monoinfected population. Upregulated levels of RANTES were shown in HIV‐1/HTLV‐1 after 1 and 3 days of culture (P < 0.05). Lymphocytes from HIV‐1/HTLV‐2 coinfected individuals showed significant CCR5 downregulation after 1 and 3 days of culture compared to lymphocytes from HIV‐1 and uninfected groups (P < 0.05). Lower percentages of CCR5‐positive cells were found in HIV‐1/HTLV‐1 coinfected after 3 days of incubation (P < 0.05). Levels of proliferation were significantly higher in the HIV‐1/HTLV‐1 group compared to HIV‐1 alone (P < 0.05). HTLV‐2 and HTLV‐1 infections may induce the involvement of innate immunity against HIV‐1 via stimulation of CC‐chemokines and receptors, potentially modifying CCR5/HIV‐1 binding and HIV‐1 progression in coinfected individuals. J. Med. Virol. 87:790–797, 2015.

Human T cell leukaemia virus type 2 tax protein mediates CC-chemokine expression in peripheral blood mononuclear cells via the nuclear factor kappa B canonical pathway

Retroviral co‐infections with human immunodeficiency virus type‐1 (HIV‐1) and human T cell leukaemia virus type 1 (HTLV‐1) or type 2 (HTLV‐2) are prevalent in many areas worldwide. It has been observed that HIV‐1/HTLV‐2 co‐infections are associated with slower rates of CD4+ T cell decline and delayed progression to AIDS. This immunological benefit has been linked to the ability of Tax2, the transcriptional activating protein of HTLV‐2, to induce the expression of macrophage inflammatory protein (MIP)‐1α/CCL3, MIP‐1β/CCL4 and regulated upon activation normal T cell expressed and secreted (RANTES)/CCL5 and to down‐regulate the expression of the CCR5 co‐receptor in peripheral blood mononuclear cells (PBMCs). This study aimed to assess the role of Tax2‐mediated activation of the nuclear factor kappa B (NF‐κB) signalling pathway on the production of the anti‐viral CC‐chemokines MIP‐1α, MIP‐1β and RANTES. Recombinant Tax1 and Tax2 proteins, or proteins expressed via adenoviral vectors used to infect cells, were tested for their ability to activate the NF‐κB pathway in cultured PBMCs in the presence or absence of NF‐κB pathway inhibitors. Results showed a significant release of MIP‐1α, MIP‐1β and RANTES by PBMCs after the activation of p65/RelA and p50. The secretion of these CC‐chemokines was significantly reduced (P < 0·05) by canonical NF‐κB signalling inhibitors. In conclusion, Tax2 protein may promote innate anti‐viral immune responses through the activation of the canonical NF‐κB pathway.

Recombinant Tax1 and Tax2 proteins inhibit HIV-1 replication in peripheral blood mononuclear cells

Patients with HIV-1 and HTLV-2 coinfections often exhibit a clinical course similar to HIV-1 infected long-term nonprogressors. This observation has been attributed in part to the ability of the HTLV Tax2 protein to activate production of antiviral chemokines and to downregulate the CCR5 co receptor on lymphocytes. Therefore we investigated the possibility that a recombinant Tax2 protein could suppress HIV-1 viral replication in vitro. R5-tropic HIV-1 (NLAD8)-infected-PBMCs were treated daily with recombinant Tax1 and Tax2 proteins (dosage range 1-100 pM). Culture supernatants were collected at intervals for 22 days post-infection and assayed for levels of HIV-1 p24 antigen. Treatment of PBMCs with Tax2 protein resulted in significant reduction in HIV-1 p24 antigen levels (p<0.05) at days 10, 14, and 18 post-infection compared to HIV-1-infected or mock-treated PBMCs. This was preceded by the detection of increased levels of CC-chemokines MIP-1α/CCL3, MIP-1β/CCL4, and RANTES/CCL5, on days 1-7 of infection (p<0.05). Similar, but less robust inhibition was determined in Tax1 treated PBMCs. Addition of Tax2 proteins starting 48 hours previous to infection resulted in a significant inhibition of HIV-1 p24 levels (p<0.05 at days 7 to 14 compared to the untreated, R5 infected PBMCs. In contrast, when addition of Tax2 began two days after R5 infection, significant HIV-1 p24 levels were only determined at days 7 and 10 for 1 pM and at day 7 for 10 pM (p<0.05). These results support the contention that Tax1 and Tax2 play a role in generating antiviral responses against HIV-1 in vivo and in vitro.