Curcumin suppresses T cell activation by blocking Ca2+ mobilization and nuclear factor of activated T cells (NFAT) activation

Immunomodulatory Effects of Curcumin on CAR T-Cell Therapy

Chimeric Antigen Receptor (CAR) T-cell therapy has revolutionized the treatment of hematological malignancies, demonstrating high efficacy in targeting and eliminating cancer cells. However, its clinical application can be associated with the risk of acute adverse effects, including cytokine release syndrome (CRS), a severe inflammatory response caused by excessive cytokine production. While anti-cytokine therapies are available to manage CRS, additional strategies are needed to optimize CAR T-cell efficacy with reduced toxicities. Curcumin, a bioactive polyphenol known for its anti-inflammatory and antioxidant properties, represents a promising adjunct for CAR T-cell therapy. In this study, we investigated the effects of curcumin on anti-CD19 CAR T-cells in vitro. Our results show that curcumin enhances the cytotoxic activity of CAR T-cells against Nalm-6, a B-cell acute lymphoblastic leukemia model, while reducing the production of pro-inflammatory cytokines, including IL-2 and IFN-γ. To explore its underlying mechanisms, network pharmacology and molecular docking analyses were performed, which revealed that curcumin interacts with key signaling pathways involved in T-cell activation and cytokine regulation. These findings support the potential of curcumin as a therapeutic adjunct to improve CAR T-cell efficacy while mitigating inflammatory toxicity.

The Dynamic Role of Curcumin in Mitigating Human Illnesses: Recent Advances in Therapeutic Applications

Herbal medicine, particularly in developing regions, remains highly popular due to its cost-effectiveness, accessibility, and minimal risk of adverse effects. Curcuma longa L., commonly known as turmeric, exemplifies such herbal remedies with its extensive history of culinary and medicinal applications across Asia for thousands of years. Traditionally utilized as a dye, flavoring, and in cultural rituals, turmeric has also been employed to treat a spectrum of medical conditions, including inflammatory, bacterial, and fungal infections, jaundice, tumors, and ulcers. Building on this longstanding use, contemporary biochemical and clinical research has identified curcumin-the primary active compound in turmeric-as possessing significant therapeutic potential. This review hypothesizes that curcumin's antioxidant properties are pivotal in preventing and treating chronic inflammatory diseases, which are often precursors to more severe conditions, such as cancer, and neurological disorders, like Parkinson's and Alzheimer's disease. Additionally, while curcumin demonstrates a favorable safety profile, its anticoagulant effects warrant cautious application. This article synthesizes recent studies to elucidate the molecular mechanisms underlying curcumin's actions and evaluates its therapeutic efficacy in various human illnesses, including cancer, inflammatory bowel disease, osteoarthritis, atherosclerosis, peptic ulcers, COVID-19, psoriasis, vitiligo, and depression. By integrating diverse research findings, this review aims to provide a comprehensive perspective on curcumin's role in modern medicine and its potential as a multifaceted therapeutic agent.

Impact of a varied set of stimuli on a suite of immunological parameters within peripheral blood mononuclear cells: toward a non-animal approach for assessing immune modulation by materials intended for human use

Introduction: In toxicology, steps are being taken towards more mechanism-focused and human relevant approaches to risk assessment, requiring new approaches and methods. Additionally, there is increasing emphasis by regulators on risk assessment of immunotoxicity. Methods: Here we present data from a peripheral blood mononuclear cell (PBMC) system whereby a varied set of stimuli, including those against the TCR and Toll-like receptors, enable readouts of cytokine and prostaglandin E2 (PGE2) production with monocyte, T cell and B cell viability, proliferation, and associated activation markers. In addition to results on the impact of the stimuli used, initial profiling data for a case study chemical, curcumin, is presented, illustrating how the system can be used to generate information on the impact of exogenous materials on three major constituent immune cell subsets for use in risk assessment and to direct follow-on studies. Results: The different stimuli drove distinct responses, not only in relation to the "quantity" of the response but also the "quality". Curcumin had a limited impact on the B cell parameters measured, with the stimuli used, and it was noted that in contrast to T cells where there was either no impact or a reduction in viability and proliferation with increasing concentration, for B cells there was a small but significant increase in both measurements at curcumin concentrations below 20 µM. Similarly, whilst expression of activation markers by T cells was reduced by the highest concentration of curcumin, they were increased in B cells. Curcumin only impacted the viability of stimulated monocytes at the highest concentration and had differential impact on different activation markers. Levels of all cytokines and PGE2 were reduced at higher concentrations. Discussion: Although the platform has certain limitations, it nevertheless enables assessment of healthy baseline monocyte, T-, and B-cell responses, and scrutiny of the impact of different stimuli to detect potential immune suppression or enhancement from exogenous materials. In the case of curcumin, a pattern of responses indicative of immune suppressive / anti-inflammatory effects was detected. It is an accessible, highly modifiable system that can be used to screen materials and guide further studies, providing a holistic, integrated picture of effects.

The role of Ca2+-signaling in the regulation of epigenetic mechanisms

Epigenetic mechanisms regulate multiple cell functions like gene expression and chromatin conformation and stability, and its misregulation could lead to several diseases including cancer. Epigenetic drugs are currently under investigation in a broad range of diseases, but the cellular processes involved in regulating epigenetic mechanisms are not fully understood. Calcium (Ca2+) signaling regulates several cellular mechanisms such as proliferation, gene expression, and metabolism, among others. Moreover, Ca2+ signaling is also involved in diseases such as neurological disorders, cardiac, and cancer. Evidence indicates that Ca2+ signaling and epigenetics are involved in the same cellular functions, which suggests a possible interplay between both mechanisms. Ca2+-activated transcription factors regulate the recruitment of chromatin remodeling complexes into their target genes, and Ca2+-sensing proteins modulate their activity and intracellular localization. Thus, Ca2+ signaling is an important regulator of epigenetic mechanisms. Moreover, Ca2+ signaling activates epigenetic mechanisms that in turn regulate genes involved in Ca2+ signaling, suggesting possible feedback between both mechanisms. The understanding of how epigenetics are regulated could lead to developing better therapeutical approaches.

Role of curcumin in the treatment of acute kidney injury: research challenges and opportunities

BACKGROUND

Acute kidney injury (AKI) is a common complication in clinical inpatients, and it continues a high morbidity and mortality rate despite many clinical treatment measures. AKI is triggered by infections, surgery, heavy metal exposure and drug side effects, but current chemical drugs often fall short of expectations for AKI treatment and have toxic side effects. Therefore, finding new interventions and treatments, especially of natural origin, is of remarkable clinical significance and application. The herbal monomer curcumin is a natural phenolic compound extracted from the plant Curcuma longa and showed various biological activities, including AKI. Furthermore, recent studies have shown that curcumin restores renal function by modulating the immune system and the release of inflammatory mediators, scavenging oxygen free radicals, reducing apoptosis and improving mitochondrial dynamics. However, curcumin has a low bioavailability, which limits its clinical application. For this reason, it is essential to investigate the therapeutic effects and molecular mechanisms of curcumin in AKI, as well as to improve its bioavailability for curcumin formulation development and clinical application.

PURPOSE

This review summarizes the sources, pharmacokinetics, and limitations in the clinical application of curcumin and explores methods to optimize its bioavailability using nanotechnology. In particular, the therapeutic effects and molecular mechanisms of curcumin on AKI are highlighted to provide a theoretical basis for AKI treatment in clinical practices.

METHODS

This review was specifically searched by means of a search of three databases (Web of Science, PubMed and Science Direct), till December 2021. Search terms were "Curcumin", "Acute kidney injury", "AKI", " Pharmacokinetics", "Mitochondria" and "Nano formulations". The retrieved data followed PRISMA criteria (preferred reporting items for systematic review) RESULTS: Studies have shown that curcumin responded to AKI-induced renal injury and restored renal tubular epithelial cell function by affecting multiple signaling pathways in AKI models induced by factors such as cisplatin, lipopolysaccharide, ischemia/reperfusion, gentamicin and potassium dichromate. Curcumin was able to affect NF-κB signaling pathway and reduce the expression of IL-1β, IL-6, IL-8 and TNF-α, thus preventing renal inflammatory injury. In the prevention of renal tubular oxidative damage, curcumin reduced ROS production by activating the activity of Nrf2, HO-1 and PGC-1α. In addition, curcumin restored mitochondrial homeostasis by upregulating OPA1 and downregulating DRP1 expression, while reducing apoptosis by inhibiting the caspase-3 apoptotic pathway. In addition, due to the low bioavailability and poor absorption of curcumin in vivo, curcumin nanoformulations including nanoparticles, liposomes, and polymeric micelles are formulated to improve the bioavailability.

CONCLUSION

This review provides new ideas for the use of curcumin in the prevention and treatment of AKI by modulating the molecular targets of several different cellular signaling pathways.

Engineering Curcumin Biosynthesis in Poplar Affects Lignification and Biomass Yield

Lignocellulosic biomass is recalcitrant toward deconstruction into simple sugars mainly due to the presence of lignin. By engineering plants to partially replace traditional lignin monomers with alternative ones, lignin degradability and extractability can be enhanced. Previously, the alternative monomer curcumin has been successfully produced and incorporated into lignified cell walls of Arabidopsis by the heterologous expression of DIKETIDE-CoA SYNTHASE (DCS) and CURCUMIN SYNTHASE2 (CURS2). The resulting transgenic plants did not suffer from yield penalties and had an increased saccharification yield after alkaline pretreatment. Here, we translated this strategy into the bio-energy crop poplar. Via the heterologous expression of DCS and CURS2 under the control of the secondary cell wall CELLULOSE SYNTHASE A8-B promoter (ProCesA8-B), curcumin was also produced and incorporated into the lignified cell walls of poplar. ProCesA8-B:DCS_CURS2 transgenic poplars, however, suffered from shoot-tip necrosis and yield penalties. Compared to that of the wild-type (WT), the wood of transgenic poplars had 21% less cellulose, 28% more matrix polysaccharides, 23% more lignin and a significantly altered lignin composition. More specifically, ProCesA8-B:DCS_CURS2 lignin had a reduced syringyl/guaiacyl unit (S/G) ratio, an increased frequency of p-hydroxyphenyl (H) units, a decreased frequency of p-hydroxybenzoates and a higher fraction of phenylcoumaran units. Without, or with alkaline or hot water pretreatment, the saccharification efficiency of the transgenic lines was equal to that of the WT. These differences in (growth) phenotype illustrate that translational research in crops is essential to assess the value of an engineering strategy for applications. Further fine-tuning of this research strategy (e.g., by using more specific promoters or by translating this strategy to other crops such as maize) might lead to transgenic bio-energy crops with cell walls more amenable to deconstruction without settling in yield.

Promising role of curcumin against viral diseases emphasizing COVID-19 management: A review on the mechanistic insights with reference to host-pathogen interaction and immunomodulation

Curcumin has already acknowledged immense interest from both medical and scientific research because of its multifaceted activity. To date, the promising effects of curcumin were perceived against numerous inflammatory diseases. Besides, curcumin's role as a medicine has been studied in many virus infections like influenza, HIV, etc. There is a need to analyze the cellular mechanisms of curcumin including host-pathogen interaction and immunomodulatory effects, to explore the role of curcumin against COVID-19. With this background, our study suggests that curcumin can prevent COVID-19 infections by inhibiting the pathogen entry, viral genome replication and steps in the endosomal pathway along with inhibition of T-cell signalling by impairing the autophagy-mediated antigen-presenting pathway. This review explicit the possible mechanisms behind curcumin-induced cellular immunity and a therapeutive dosage of curcumin suggesting a preventive strategy against COVID-19.

Curcumin Prevents Cerebellar Hypoplasia and Restores the Behavior in Hyperbilirubinemic Gunn Rat by a Pleiotropic Effect on the Molecular Effectors of Brain Damage

Bilirubin toxicity to the central nervous system (CNS) is responsible for severe and permanent neurologic damage, resulting in hearing loss, cognitive, and movement impairment. Timely and effective management of severe neonatal hyperbilirubinemia by phototherapy or exchange transfusion is crucial for avoiding permanent neurological consequences, but these therapies are not always possible, particularly in low-income countries. To explore alternative options, we investigated a pharmaceutical approach focused on protecting the CNS from pigment toxicity, independently from serum bilirubin level. To this goal, we tested the ability of curcumin, a nutraceutical already used with relevant results in animal models as well as in clinics in other diseases, in the Gunn rat, the spontaneous model of neonatal hyperbilirubinemia. Curcumin treatment fully abolished the landmark cerebellar hypoplasia of Gunn rat, restoring the histological features, and reverting the behavioral abnormalities present in the hyperbilirubinemic rat. The protection was mediated by a multi-target action on the main bilirubin-induced pathological mechanism ongoing CNS damage (inflammation, redox imbalance, and glutamate neurotoxicity). If confirmed by independent studies, the result suggests the potential of curcumin as an alternative/complementary approach to bilirubin-induced brain damage in the clinical scenario.

Localized Immunosuppression With Tannic Acid Encapsulation Delays Islet Allograft and Autoimmune-Mediated Rejection

Type 1 diabetes (T1D) is an autoimmune disease of insulin-producing β-cells. Islet transplantation is a promising treatment for T1D, but long-term graft viability and function remain challenging. Oxidative stress plays a key role in the activation of alloreactive and autoreactive immunity toward the engrafted islets. Therefore, targeting these pathways by encapsulating islets with an antioxidant may delay immune-mediated rejection. Utilizing a layer-by-layer approach, we generated nanothin encapsulation materials containing tannic acid (TA), a polyphenolic compound with redox scavenging and anti-inflammatory effects, and poly(N-vinylpyrrolidone) (PVPON), a biocompatible polymer. We hypothesize that transplantation of PVPON/TA-encapsulated allogeneic C57BL/6 islets into diabetic NOD mice will prolong graft function and elicit localized immunosuppression. In the absence of systemic immunosuppression, diabetic recipients containing PVPON/TA-encapsulated islets maintained euglycemia and delayed graft rejection significantly longer than those receiving nonencapsulated islets. Transplantation of PVPON/TA-encapsulated islets was immunomodulatory because gene expression and flow cytometric analysis revealed significantly decreased immune cell infiltration, synthesis of reactive oxygen species, inflammatory chemokines, cytokines, CD8 T-cell effector responses, and concomitant increases in alternatively activated M2 macrophage and dendritic cell phenotypes. Our results provide evidence that reducing oxidative stress following allotransplantation of PVPON/TA-encapsulated islets can elicit localized immunosuppression and potentially delay graft destruction in future human islet transplantation studies.

Biochemistry, Safety, Pharmacological Activities, and Clinical Applications of Turmeric: A Mechanistic Review

Turmeric (Curcuma longa L.) is a popular natural drug, traditionally used for the treatment of a wide range of diseases. Its root, as its most popular part used for medicinal purposes, contains different types of phytochemicals and minerals. This review summarizes what is currently known on biochemistry, safety, pharmacological activities (mechanistically), and clinical applications of turmeric. In short, curcumin is considered as the fundamental constituent in ground turmeric rhizome. Turmeric possesses several biological activities including anti-inflammatory, antioxidant, anticancer, antimutagenic, antimicrobial, antiobesity, hypolipidemic, cardioprotective, and neuroprotective effects. These reported pharmacologic activities make turmeric an important option for further clinical research. Also, there is a discussion on its safety and toxicity.

Co-delivery of rituximab targeted curcumin and imatinib nanostructured lipid carriers in non-Hodgkin lymphoma cells

The aim of the present study was production of nanostructured lipid carriers (NLCs) of curcumin and imatinib for co-administration in non-Hodgkin lymphoma cells. NLCs were prepared and conjugated to rituximab to target CD20 receptors of lymphoma cell lines. Oleic acid or Labrafac and glyceryl monostearate or lecithin were used for production of NLCs. The antibody coupling efficiency to NLCs and their physical characteristics were studied. The cytotoxicity of NLCs on Jurkat T cells (CD20 receptor negative) and Ramos B cells (CD20 receptor positive) was studied by MTT assay. The cellular uptake was determined by fluorescent microscopy. The results indicated both curcumin and imatinib targeted NLCs had a significant cytotoxic effect much higher than the free drugs and non-targeted NLCs on Ramos cells. In both cell lines, the cytotoxicity of the co-administrated drugs was significantly higher than each drug alone. In Ramos cells the co-administration of curcumin (15 μg/ml)/imatinib (5 μg/ml) decreased the free curcumin IC₅₀ from 8.3 ± 0.9 to 1.9 ± 0.2 μg/ml, and curcumin targeted NLCs from 6.7 ± 0.1 to 1.3 ± 0.2 μg/ml. In this case the IC₅₀ of imatinib was reduced from 11.1 ± 0.7 to 2.3 ± 0.1 μg/ml and imatinib targeted NLCs from 4.3 ± 0.1 to 1.4 ± 0.0 μg/ml. The co-administration of ritoximab conjugated NLCs of curcumin and imatinib may enhance cytotoxicity of imatinib in treatment of non-Hodgkin lymphoma.

Curcumin Attenuates Both Acute and Chronic Immune Nephritis

Curcumin is known to have immunomodulatory potential in addition to anti-oxidant, anti-inflammatory and anti-carcinogenic effects. The aim of the present study is to investigate the therapeutic effects of curcumin on immune-mediated renal disease in an anti-glomerular basement membrane (GBM) model (representing acute kidney Injury, AKI) and murine lupus model (representing chronic kidney disease, CKD). In the AKI model, female anti-GBM 129/svj mice were administered with curcumin right before disease induction. In the CKD model, female MRL.lpr mice at the age of 8-10 weeks old were treated with curcumin or placebo via oral gavage daily for two months. After treatment, serum autoantibody levels, splenomegaly and spleen cellularity were reduced in murine lupus. Collectively, curcumin ameliorated kidney disease in the two mouse models with either acute or chronic nephritis, as marked by reduced proteinuria, blood urea nitrogen, glomerulonephritis, crescent formation, tubule-interstitial disease, and renal infiltration by lymphocytes. In addition, curcumin treatment reduced activation of the NFkB, MAPK, AKT and pBAD pathways either systemically, or within the inflamed kidneys. These findings suggest that natural food supplements could become an alternative approach to ameliorating immune-mediated kidney diseases.

Curcumin mediates attenuation of pro-inflammatory interferon γ and interleukin 17 cytokine responses in psoriatic disease, strengthening its role as a dietary immunosuppressant

Curcumin exhibits anti-inflammatory properties and has been used for centuries in traditional medicine and as dietary supplement. Data from clinical trials has strengthened the notion that curcumin may exert an anti-inflammatory and immunosuppressive role in patients with psoriatic disease, but its mode of action has remained elusive. We hypothesized that curcumin could inhibit interferon (IFN)-γ and interleukin (IL)-17 production in peripheral blood mononuclear cells from patients with psoriasis and psoriatic arthritis (PsA). To this end, we assessed the in vitro effect of curcumin on IFN-γ production by cluster differentiation (CD)4(+), CD8(+) T cells, natural killer (NK) and NKT cells and on IL-17 production by CD4(+) T cells from 34 patients with psoriatic disease (22 with psoriasis and 12 with PsA); 15 normal subjects were included as healthy controls. We also assessed the effect of curcumin on signal transducer and activator of transcription (STAT)3 activation. Curcumin significantly decreased, in a dose dependent manner, IFNγ-production by CD4(+) and CD8(+) T cells, and NK and NKT cells in patients with psoriatic disease and healthy controls. It also decreased IL-17 production by CD4(+) T cells (Th17). At the molecular level, curcumin increased STAT3 serine 727 phosphorylation intensity and p-STAT3(+) CD4(+) T cells in patients with PsA and psoriasis. In conclusion, curcumin in vitro inhibits pro-inflammatory IFN-γ and IL-17 production in psoriatic disease, and this may strengthen its role as a dietary immunosuppressant in patients with this disease.

Curcumin Elevates TFH Cells and Germinal Center B Cell Response for Antibody Production in Mice

Curcumin is a natural product extracted from Curcuma longa. It has been reported as a potent antioxidant and anti-inflammatory compound. Previous studies have demonstrated that curcumin suppresses pro-inflammatory cytokine production via inhibition of NF-κB in macrophages. However, its role in adaptive immune cells such as T cells, in vivo, has not clearly been elucidated. Here, we examined the effects of curcumin in T follicular helper (T_FH) cells and on Ab production during NP-ovalbumin immunization in mice. The results revealed that curcumin administered daily significantly increased CXCR5⁺B-cell lymphoma 6⁺ T_FH cells and CD95⁺GL-7⁺ germinal center (GC) B cells in draining lymph nodes. In addition, curcumin treatment in mice induced total Ab production as well as high affinity IgG1 and IgG2b Ab production. Collectively, these results suggest that curcumin has positive regulatory roles in T_FH cell functions and GC responses. Thus, this could be an advantageous supplement to enhance humoral immunity against infectious diseases and cancer.

Hyaluronic acid-curcumin conjugate suppresses the fibrotic functions of myofibroblasts from contractive joint by the PTGER2 demethylation

Joint contracture is a fibrotic complication induced by joint immobilization and trauma, which is characterized as excessive myofibroblast proliferation in joint capsule. The treatments of joint contracture are unsatisfied and patients are suffered from joint dysfunction. Our previous study has shown that curcumin can inhibit myofibroblast proliferation in vitro, but the major challenge is the low aqueous solubility and biological activity of curcumin. In this study, hyaluronic acid-curcumin (HA-Cur) conjugate was synthesized to suppress myofibroblasts in joint contracture. Cells were isolated from the joint capsules of joint contracture patients and induced to active myofibroblasts by transforming growth factor-β (TGF-β). The anti-fibrotic function and mechanisms of HA-Cur were investigated by immunohistochemistry, reverse transcription-quantitative polymerase chain reaction (PCR), methylation-specific PCR, western blot, transwell migration assay and proliferation assay. Results showed that 30 μM HA-Cur significantly attenuated the fibrotic functions of myofibroblast in joint contracture in vitro by regulating the methylation of prostaglandin E receptor 2 (PTGER2) and inhibiting TGF-β signaling. This may provide a mechanism for the treatment of joint contracture, and provide a molecular target PTGER2 for therapy during the pathogenesis of joint contracture.

Albumin evokes Ca2+-induced cell oxidative stress and apoptosis through TRPM2 channel in renal collecting duct cells reduced by curcumin

In proteinuric nephropathies of chronic kidney disease, the epithelial cells of the nephron including the collecting duct are exposed to high concentrations of luminal albumin. Albumin is taken up from collecting duct cells by endocytosis causing excessive reactive oxygen species (ROS) production and a proinflammatory response. Curcumin used in the traditional medicine possesses anti-inflammatory and antioxidant effects. ROS and ADP-ribose (ADPR) activate the cation channel TRPM2. We hypothesize, that albumin-induced cell stress and proinflammatory response are mediated by Ca²⁺ and can be reduced by curcumin. The cortical collecting duct (CCD) cells mpkCCD_c14 exhibit spontaneous and inducible Ca²⁺ oscillations, which can be blocked by pre-treatment with curcumin. Curcumin accumulates in plasma membrane and intracellular vesicles, where it interferes with TRPM2 and decreases the influx of Ca²⁺. Albumin reduces cell viability and increases apoptosis, NF-κB activation, and mitochondrial membrane depolarization via Ca²⁺-dependent signaling, which results in increased ROS production. Albumin-induced cell stress is diminished by the inhibition of TRPM2 after administration of curcumin and ADPR (PARP1) inhibitors. Curcumin did not reduce the Ca2+ elevation induced by thapsigargin in Ca²⁺-free medium, but it reduced the function of store-operated Ca²⁺ channels and ATP-evoked Ca²⁺ response. In conclusion, albumin-induced oxidative stress is mediated by Ca²⁺-dependent signaling via TRPM2 and leads to cell damage and a proinflammatory response, strengthening the role of CCD cells in the progression of chronic kidney disease.

Curcumin inhibits NF-kB and Wnt/β-catenin pathways in cervical cancer cells

Curcumin is a natural non-toxic phenol which is isolated from Curcumin longa L. Mounting evidence has revealed the anticancer properties of curcumin in various tumors, but the underlying molecular mechanisms of this suppression in cervical cancer is still remained unclear. Here we assessed the antitumor effects of curcumin compared with 5-Fluorouracil in Hella cells in spheroids models and monolayer cell cultures. The anti-proliferative effects of curcumin and 5-Fluorouracil were as examined in spheroid and monolayer models. The expression levels of Wnt/β-catenin and NF-kB pathways as well as the influence of the cell cycle were evaluated. Curcumin inhibited cell growth in Hella cells through the regulation of NF-kB and Wnt pathways. Also, cells developed a G2/M cell cycle arrest followed by sub-G1 apoptosis with 5-Fluorouracil and curcumin. It was also shown that curcumin either considerably affects the Wnt/β-catenin and NF-kB pathways. We showed that curcumin inhibits invasion and proliferation of cervical cancer cells via impairment of NF-kB and Wnt/β-catenin pathways, proposing further studies on the potential impacts of this compound on cancer therapy.

Targeting the balance of T helper cell responses by curcumin in inflammatory and autoimmune states

CD4+ T helper (Th) cells are a crucial player in host defense but under certain conditions can contribute to the pathogenesis of inflammatory and autoimmune diseases. Beside the Th1/Th2 subset, several additional Th subsets have been identified, each with a distinctive transcription factor, functional properties, signature cytokine profile, and possible role in the pathophysiology of diseases. These newer Th subsets include Th17, regulatory Th cells (Tregs), and more recently, Th9, Th22, and follicular T helper cells. Interestingly, imbalance of Th subsets contributes to the immunopathology of several disease states. Therefore, targeting the imbalance of Th subsets and their signature cytokine profiles by a safe, effective and inexpensive nutraceutical agent such as curcumin could be helpful to treat autoimmune and inflammatory diseases. In this study different Th subsets and how the imbalance of these subsets could promote pathology of several diseases has been reviewed. Furthermore, the role of curcumin in this process will be discussed and the impact of targeting Th subsets by curcumin.

A Phase 2 Study to Assess the Immunomodulatory Capacity of a Lecithin-based Delivery System of Curcumin in Endometrial Cancer

Curcumin is a botanical with anti-tumor and immunomodulatory properties. We hypothesized that curcumin supplementation might influence inflammatory biomarker levels in endometrial carcinoma (EC). In this open-label, non-randomized phase 2 study (NCT02017353), seven EC patients consumed 2 g/day Curcumin Phytosome (CP) orally for 2 weeks. Blood was taken at baseline, days 1, 7, 14, and 21. The following analytes were measured: curcuminoids and metabolites, 56 inflammatory biomarkers, COX-2, frequencies of myeloid-derived suppressor cells, dendritic cells and NK cells, expression of MHC molecules on leukocytes and monocytes and activation/memory status of T cells. Patients completed quality of life (QoL) questionnaires at baseline and end of treatment. Curcumin metabolites were detectable in plasma upon CP intake. CP downregulated MHC expression levels on leukocytes (P = 0.0313), the frequency of monocytes (P = 0.0114) and ICOS expression by CD8⁺ T cells (P = 0.0002). However, CP upregulated CD69 levels on CD16⁻ NK cells (P = 0.0313). No differences were observed regarding inflammatory biomarkers, frequencies of other immune cell types, T cell activation and COX-2 expression. A non-significant trend to improved QoL was observed. Overall, CP-induced immunomodulatory effects in EC were modest without significant QoL changes. Given the small population and the observed variability in inter-patient biomarker levels, more research is necessary to explore whether benefits of CP can be obtained in EC by different supplementation regimens.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT02017353; www.clinicaltrialsregister.eu, identifier 2013-001737-40.

Curcumin exerts anti-inflammatory and vasoprotective effects through amelioration of NFAT-dependent endothelin-1 production in mice with acute Chagas cardiomyopathy

BACKGROUND

The anti-inflammatory and cardioprotective properties of curcumin (Cur), a natural polyphenolic flavonoid isolated from the rhizomes of Curcuma longa, are increasingly considered to have beneficial effects on the progression of Chagas heart disease, caused by the protozoan parasite Trypanosoma cruzi.

OBJECTIVE

To evaluate the effects of oral therapy with Cur on T. cruzi-mediated cardiovasculopathy in acutely infected mice and analyse the in vitro response of parasite-infected human microvascular endothelial cells treated with this phytochemical.

METHODS

Inflammation of heart vessels from Cur-treated and untreated infected mice were analysed by histology, with benznidazole (Bz) as the reference compound. Parasitaemia was monitored by the direct method. Capillary permeability was visualised by Evans-blue assay. Myocardial ET-1, IL-6, and TNF-α mRNA expressions were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Microvascular endothelial HMEC-1 cells were infected in vitro with or without addition of Cur or Bz. Induction of the Ca2+/NFAT pathway was assessed by fluorometry, immunoblotting, and reporter assay.

FINDINGS

Oral Cur therapy of recently infected mice reduced inflammatory cell infiltration of myocardial arteries without lowering parasite levels. Compared to that of the phosphate-buffered saline-receiving group, hearts from Cur-treated mice showed significantly decreased vessel inflammation scores (p < 0.001), vascular permeabilities (p < 0.001), and levels of IL-6/TNF-α (p < 0.01) and ET-1 (p < 0.05) mRNA. Moreover, Cur significantly (p < 0.05 for transcript; p < 0.01 for peptide) downregulated ET-1 secretion from infected HMEC-1 cells. Remarkably, Cur addition significantly (p < 0.05 at 27.0 μM) interfered with T. cruzi-dependent activation of the Ca2+/NFATc1 signalling pathway that promotes generation of inflammatory agents in HMEC-1 cells.

CONCLUSIONS

Oral treatment with Cur dampens cardiovasculopathy in acute Chagas mice. Cur impairs the Ca2+/NFATc1-regulated release of ET-1 from T. cruzi-infected vascular endothelium. These findings identify new perspectives for exploring the potential of Cur-based interventions to ameliorate Chagas heart disease.

Cancer-selective cytotoxic Ca2+ overload in acute myeloid leukemia cells and attenuation of disease progression in mice by synergistically acting polyphenols curcumin and carnosic acid

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy characterized by extremely heterogeneous molecular and biologic abnormalities that hamper the development of effective targeted treatment modalities. While AML cells are highly sensitive to cytotoxic Ca²⁺ overload, the feasibility of Ca²⁺- targeted therapy of this disease remains unclear. Here, we show that apoptotic response of AML cells to the synergistically acting polyphenols curcumin (CUR) and carnosic acid (CA), combined at low, non-cytotoxic doses of each compound was mediated solely by disruption of cellular Ca²⁺ homeostasis. Specifically, activation of caspase cascade in CUR+CA-treated AML cells resulted from sustained elevation of cytosolic Ca²⁺ (Ca²⁺_cyt) and was not preceded by endoplasmic reticulum stress or mitochondrial damage. The CUR+CA-induced Ca²⁺_cyt rise did not involve excessive influx of extracellular Ca²⁺ but, rather, occurred due to massive Ca²⁺ release from intracellular stores concomitant with inhibition of Ca²⁺_cyt extrusion through the plasma membrane. Notably, the CUR+CA combination did not alter Ca²⁺ homeostasis and viability in non-neoplastic hematopoietic cells, suggesting its cancer-selective action. Most importantly, co-administration of CUR and CA to AML-bearing mice markedly attenuated disease progression in two animal models. Collectively, our results provide the mechanistic and translational basis for further characterization of this combination as a prototype of novel Ca²⁺-targeted pharmacological tools for the treatment of AML.

Activation of Neutrophils via IP3 Pathway Following Exposure to Demodex-Associated Bacterial Proteins

Rosacea is a chronic inflammatory condition that predominantly affects the skin of the face. Sera from rosacea patients display elevated reactivity to proteins from a bacterium (Bacillus oleronius) originally isolated from a Demodex mite from a rosacea patient suggesting a possible role for bacteria in the induction and persistence of this condition. This work investigated the ability of B. oleronius proteins to activate neutrophils and demonstrated activation via the IP3 pathway. Activated neutrophils displayed increased levels of IP1 production, F-actin formation, chemotaxis, and production of the pro-inflammatory cytokines IL-1β and IL-6 following stimulation by pure and crude B. oleronius protein preparations (2 μg/ml), respectively. In addition, neutrophils exposed to pure and crude B. oleronius proteins (2 μg/ml) demonstrated increased release of internally stored calcium (Ca(2+)), a hallmark of the IP3 pathway of neutrophil activation. Neutrophils play a significant role in the inflammation associated with rosacea, and this work demonstrates how B. oleronius proteins can induce neutrophil recruitment and activation.

Cardioprotective actions of curcumin on the pathogenic NFAT/COX-2/prostaglandin E2 pathway induced during Trypanosoma cruzi infection

BACKGROUND

Diverse cardiovascular signaling routes have been considered critical for Chagas cardiomyopathy caused by the protozoan parasite Trypanosoma cruzi. Along this line, T. cruzi infection and endothelin-1 (ET-1) have been shown to cooperatively activate the Ca²⁺/NFAT cascade in cardiomyocytes, leading to cyclooxygenase type 2 (COX-2) induction and increased release of prostanoids and prohypertrophic peptides.

PURPOSE

To determine whether the well-known cardioprotective and anti-inflammatory effects of curcumin (Cur) could be helpful to interfere with this key machinery for pathogenesis of Chagas myocarditis.

STUDY DESIGN

Cur treatment was evaluated through in vivo studies using a murine model of acute T. cruzi infection and in vitro experiments using ET-1-stimulated and parasite-infected mouse cardiomyocytes.

METHODS

Cur-treated and untreated infected mice were followed-up to estimate survival postinfection and heart tissues from both groups were analyzed for inflammatory infiltration by histopathology, whereas parasite load, induction of arachidonic acid pathway and natriuretic peptide expression were determined by real-time PCR. Molecular analysis of Cur myocardial targets included intracellular calcium measurement, NFAT and COX-2 induction in transfected cells, and assessment of NFAT, COX-2 and microsomal prostaglandin E synthase-1 (mPGES-1) levels by immunoblotting, prostaglandin E₂ (PGE₂) by ELISA, b-type natriuretic peptide (BNP) by real-time PCR, and PGE₂/EP4 receptor/BNP interaction by transwell experiments.

RESULTS

Cur treatment of acute Chagas mice enhanced survival and proved to hinder relevant inflammatory processes in the heart, including leukocyte recruitment, activation of the eicosanoid pathway and BNP overexpression, without modifying parasite burden in the organ. Cur was capable of blocking Ca²⁺-dependent NFATc1 transcriptional activity, COX-2 and mPGES-1 induction, and subsequent PGE₂ production in ET-1-stimulated and parasite-infected cardiomyocytes. Furthermore, the decline of cardiomyocyte-derived prostaglandin levels achieved upon Cur treatment impaired effective PGE₂/EP4 receptor interaction, resulting in attenuated expression of BNP, a strong indicator of cardiac pathogenesis in Chagas disease, in both infected and uninfected cells.

CONCLUSION

Our current study shows a putative mechanism of action of Cur involving inhibition of the Ca²⁺/NFAT-dependent, pathogenic COX-2/mPGES-1/PGE₂ pathway in T. cruzi-infected myocytes, underlying cardioprotection achieved in Cur-treated infected mice. With a view to the limited therapeutic possibilities available, Cur represents a promising approach for the treatment of Chagas heart disease.

Curcumin attenuates cyclosporine A‑induced renal fibrosis by inhibiting hypermethylation of the klotho promoter

Chronic kidney disease is increasingly considered to be a worldwide public health problem and usually leads to renal fibrosis. In the present study, curcumin, a polyphenol pigment extracted from turmeric, was demonstrated to exert protective effects on renal fibrosis via the suppression of transforming growth factor‑β (TGF‑β) downstream signaling, such as plasminogen activator inhibitor‑1 (PAI‑1), α‑smooth muscle actin (α‑SMA) and collagen I (Col I) downregulation. The present findings demonstrate that curcumin exerted a protective effect on cyclosporine A‑induced renal fibrosis via a klotho (KL)‑dependent mechanism, which inhibits the TGF‑β signaling pathway. Further research indicated that curcumin induced KL expression in HK‑2 tubular epithelial cells by inhibiting CpG hypermethylation in the KL promoter, which mediates the loss of expression in cells. Methylation‑specific polymerase chain reaction (PCR) combined with bisulfite sequencing identified numerous key CpG sites, such as 249, 240 and 236, whose methylation statuses are important for KL expression. A PCR reporter assay was utilized to further confirm these findings. In addition, the effects of curcumin on the regulation of DNA methyltransferase 1 (Dnmt1) expression were evaluated, and the data suggest that curcumin inhibits Dnmt1 expression and restricts CpG hypermethylation. Thus, the current study reveals that curcumin attenuated renal fibrosis by suppressing CpG methylation in the KL promoter, thus inducing KL expression, which inhibited TGF‑β signaling, which may provide a novel therapeutic approach for the treatment of renal fibrosis.

A systems biology pipeline identifies new immune and disease related molecular signatures and networks in human cells during microgravity exposure

Microgravity is a prominent health hazard for astronauts, yet we understand little about its effect at the molecular systems level. In this study, we have integrated a set of systems-biology tools and databases and have analysed more than 8000 molecular pathways on published global gene expression datasets of human cells in microgravity. Hundreds of new pathways have been identified with statistical confidence for each dataset and despite the difference in cell types and experiments, around 100 of the new pathways are appeared common across the datasets. They are related to reduced inflammation, autoimmunity, diabetes and asthma. We have identified downregulation of NfκB pathway via Notch1 signalling as new pathway for reduced immunity in microgravity. Induction of few cancer types including liver cancer and leukaemia and increased drug response to cancer in microgravity are also found. Increase in olfactory signal transduction is also identified. Genes, based on their expression pattern, are clustered and mathematically stable clusters are identified. The network mapping of genes within a cluster indicates the plausible functional connections in microgravity. This pipeline gives a new systems level picture of human cells under microgravity, generates testable hypothesis and may help estimating risk and developing medicine for space missions.

Curcumin Reduces the Noise-Exposed Cochlear Fibroblasts Apoptosis

Introduction The structural changes underlying permanent noise-induced hearing loss (NIHL) include loss of the sensory hair cells, damage to their stereocilia, and supporting tissues within the cochlear lateral wall.

Objective The objective of this study is to demonstrate curcumin as a safe and effective therapeutic agent in the prevention and treatment for fibroblasts damage within the cochlear supporting tissues and lateral wall through cell death pathway.

Methods We divided 24 Rattus norvegicus into 4 groups, Group 1: control; Group 2: noise (+); Group 3: noise (+), 50 mg/day curcumin (+); Group 4: noise (+), 100 mg/day curcumin (+). We provided the noise exposure dose at 100 dB SPL for two hours over two weeks and administered the curcumin orally over two weeks. We examined all samples for the expressions of calcineurin, nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), and apoptotic index of cochlear fibroblasts.

Results We found significant differences for the expressions of calcineurin (p < 0.05) in all groups, significant differences for the expressions of NFATc1 (p < 0.05) in all groups, except in Groups 1 and 4, and significant differences for the apoptotic index (p < 0.05) in all groups.

Conclusion Curcumin proved to be potentially effective in the prevention and treatment for fibroblasts damage within the cochlear supporting tissues and lateral wall regarding the decreased expression of calcineurin, NFATc1, and apoptotic index of cochlear fibroblasts.

Curcumin Ameliorates Memory Decline via Inhibiting BACE1 Expression and β-Amyloid Pathology in 5×FAD Transgenic Mice

Alzheimer's disease (AD) is the most common dementia and the trigger of its pathological cascade is widely believed to be the overproduction and accumulation of β-amyloid protein (Aβ) in the affected brain. However, effective AD remedies are still anxiously awaited. Recent evidence suggests that curcumin may be a potential agent for AD treatment. In this study, we used 5×FAD transgenic mice as an AD model to investigate the effects of curcumin on AD. Our results showed that curcumin administration (150 or 300 mg/kg/day, intragastrically, for 60 days) dramatically reduced Aβ production by downregulating BACE1 expression, preventing synaptic degradation, and improving spatial learning and memory impairment of 5×FAD mice. These findings suggest that curcumin is a potential candidate for AD treatment.

Curcumin Ingestion Inhibits Mastocytosis and Suppresses Intestinal Anaphylaxis in a Murine Model of Food Allergy

IgE antibodies and mast cells play critical roles in the establishment of allergic responses to food antigens. Curcumin, the active ingredient of the curry spice turmeric, has anti-inflammatory properties, and thus may have the capacity to regulate Th2 cells and mucosal mast cell function during allergic responses. We assessed whether curcumin ingestion during oral allergen exposure can modulate the development of food allergy using a murine model of ovalbumin (OVA)-induced intestinal anaphylaxis. Herein, we demonstrate that frequent ingestion of curcumin during oral OVA exposure inhibits the development of mastocytosis and intestinal anaphylaxis in OVA-challenged allergic mice. Intragastric (i.g.) exposure to OVA in sensitized BALB/c mice induced a robust IgE-mediated response accompanied by enhanced OVA-IgE levels, intestinal mastocytosis, elevated serum mMCP-1, and acute diarrhea. In contrast, mice exposed to oral curcumin throughout the experimental regimen appeared to be normal and did not exhibit intense allergic diarrhea or a significant enhancement of OVA-IgE and intestinal mast cell expansion and activation. Furthermore, allergic diarrhea, mast cell activation and expansion, and Th2 responses were also suppressed in mice exposed to curcumin during the OVA-challenge phase alone, despite the presence of elevated levels of OVA-IgE, suggesting that curcumin may have a direct suppressive effect on intestinal mast cell activation and reverse food allergy symptoms in allergen-sensitized individuals. This was confirmed by observations that curcumin attenuated the expansion of both adoptively transferred bone marrow-derived mast cells (BMMCs), and inhibited their survival and activation during cell culture. Finally, the suppression of intestinal anaphylaxis by curcumin was directly linked with the inhibition of NF-κB activation in curcumin-treated allergic mice, and curcumin inhibited the phosphorylation of the p65 subunit of NF-κB in BMMCs. In summary, our data demonstrates a protective role for curcumin during allergic responses to food antigens, suggesting that frequent ingestion of this spice may modulate the outcome of disease in susceptible individuals.

The multifaceted role of curcumin in cancer prevention and treatment

Despite significant advances in treatment modalities over the last decade, neither the incidence of the disease nor the mortality due to cancer has altered in the last thirty years. Available anti-cancer drugs exhibit limited efficacy, associated with severe side effects, and are also expensive. Thus identification of pharmacological agents that do not have these disadvantages is required. Curcumin, a polyphenolic compound derived from turmeric (Curcumin longa), is one such agent that has been extensively studied over the last three to four decades for its potential anti-inflammatory and/or anti-cancer effects. Curcumin has been found to suppress initiation, progression, and metastasis of a variety of tumors. These anti-cancer effects are predominantly mediated through its negative regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other oncogenic molecules. It also abrogates proliferation of cancer cells by arresting them at different phases of the cell cycle and/or by inducing their apoptosis. The current review focuses on the diverse molecular targets modulated by curcumin that contribute to its efficacy against various human cancers.

NFAT as cancer target: mission possible?

The NFAT signaling pathway regulates various aspects of cellular functions; NFAT acts as a calcium sensor, integrating calcium signaling with other pathways involved in development and growth, immune response, and inflammatory response. The NFAT family of transcription factors regulates diverse cellular functions such as cell survival, proliferation, migration, invasion, and angiogenesis. The NFAT isoforms are constitutively activated and overexpressed in several cancer types wherein they transactivate downstream targets that play important roles in cancer development and progression. Though the NFAT family has been conclusively proved to be pivotal in cancer progression, the different isoforms play distinct roles in different cellular contexts. In this review, our discussion is focused on the mechanisms that drive the activation of various NFAT isoforms in cancer. Additionally, we analyze the potential of NFAT as a valid target for cancer prevention and therapy.

Adaptive cellular stress pathways as therapeutic targets of dietary phytochemicals: focus on the nervous system

During the past 5 decades, it has been widely promulgated that the chemicals in plants that are good for health act as direct scavengers of free radicals. Here we review evidence that favors a different hypothesis for the health benefits of plant consumption, namely, that some phytochemicals exert disease-preventive and therapeutic actions by engaging one or more adaptive cellular response pathways in cells. The evolutionary basis for the latter mechanism is grounded in the fact that plants produce natural antifeedant/noxious chemicals that discourage insects and other organisms from eating them. However, in the amounts typically consumed by humans, the phytochemicals activate one or more conserved adaptive cellular stress response pathways and thereby enhance the ability of cells to resist injury and disease. Examplesof such pathways include those involving the transcription factors nuclear factor erythroid 2-related factor 2, nuclear factor-κB, hypoxia-inducible factor 1α, peroxisome proliferator-activated receptor γ, and forkhead box subgroup O, as well as the production and action of trophic factors and hormones. Translational research to develop interventions that target these pathways may lead to new classes of therapeutic agents that act by stimulating adaptive stress response pathways to bolster endogenous defenses against tissue injury and disease. Because neurons are particularly sensitive to potentially noxious phytochemicals, we focus on the nervous system but also include findings from other cell types in which actions of phytochemicals on specific signal transduction pathways have been more thoroughly studied.

Immune regulation and anti-inflammatory effects of isogarcinol extracted from Garcinia mangostana L. against collagen-induced arthritis

Isogarcinol is a natural compound that we extracted from Garcinia mangostana L., and we were the first to report that it is a new immunosuppressant. In the present study, we investigated the immune regulation and anti-inflammatory effects of isogarcinol on collagen-induced arthritis (CIA) and explored its potential mechanism in the treatment of rheumatoid arthritis. The oral administration of isogarcinol significantly reduced clinical scores, alleviated cartilage and bone erosion, and reduced the levels of serum inflammatory cytokines in CIA mice. Isogarcinol inhibited xylene-induced mouse ear edema in vivo. In vitro, isogarcinol decreased iNOS and COX-2 mRNA expression and NO content by inhibiting NF-κB expression. Furthermore, isogarcinol decreased the activity of NFAT and inhibited IL-2 expression. The mechanism of action of isogarcinol is associated with down-regulation of both autoimmune and inflammatory reactions.

Immunotherapy of cancer via mediation of cytotoxic T lymphocytes by methionine enkephalin (MENK)

The aim of this study was to investigate the immunological mechanisms by which synthetic methionine enkephalin (MENK) exerts therapeutic effects on tumor growth. Our findings in vivo or in vitro show that MENK treatment either in vivo or in vitro could up-regulate the percentages of CD8+T cells, induce markers of activated T cells, increased cytotoxic activity against mouse S180 tumor cells and increase secretion of IFNγ. In addition, the adoptively transferred CD8+T cells, after either in vitro or in vivo treatment with MENK, result in significantly increased survival of S180 tumor-bearing mice and significant shrinkage in tumor growth. Opioid receptors are detected on normal CD8+T cells and exposure to MENK leads to increased expression of opioid receptors. Interaction between MENK and the opioid receptors on CD8+T cells appears to be essential for the activation of CTL, since the addition of naltrexone (NTX), an opioid receptor antagonist, significantly inhibits all of the effects of MENK. The evidence obtained indicates that the MENK-induced T cell signaling is associated with a significant up-regulation of Ca2+ influx into the cytoplasm and the translocation of NFAT2 into nucleus, and these signaling effects are also inhibited by naltrexone.

Curcuma Contra Cancer? Curcumin and Hodgkin's Lymphoma

Curcumin, a phytochemical isolated from curcuma plants which are used as coloring ingredient for the preparation of curry powder, has several activities which suggest that it might be an interesting drug for the treatment or prevention of cancer. Curcumin targets different pathways which are involved in the malignant phenotype of tumor cells, including the nuclear factor kappa B (NFKB) pathway. This pathway is deregulated in multiple tumor entities, including Hodgkin’s lymphoma (HL). Indeed, curcumin can inhibit growth of HL cell lines and increases the sensitivity of these cells for cisplatin. In this review we summarize curcumin activities with special focus on possible activities against HL cells.

Caloric restriction favorably impacts metabolic and immune/inflammatory profiles in obese mice but curcumin/piperine consumption adds no further benefit

Background

Obesity is associated with low-grade inflammation and impaired immune response. Caloric restriction (CR) has been shown to inhibit inflammatory response and enhance cell-mediated immune function. Curcumin, the bioactive phenolic component of turmeric spice, is proposed to have anti-obesity and anti-inflammation properties while piperine, another bioactive phenolic compound present in pepper spice, can enhance the bioavailability and efficacy of curcumin. This study sought to determine if curcumin could potentiate CR’s beneficial effect on immune and inflammatory responses in obesity developed in mice by feeding high-fat diet (HFD).

Methods

Mice were fed a HFD for 22 wk and then randomized into 5 groups: one group remained on HFD ad libitum and the remaining 4 groups were fed a 10% CR (reduced intake of HFD by 10% but maintaining the same levels of micronutrients) in the presence or absence of curcumin and/or piperine for 5 wk, after which CR was increased to 20% for an additional 33 wk. At the end of the study, mice were sacrificed, and spleen cells were isolated. Cells were stimulated with T cell mitogens, anti-CD3/CD28 antibodies, or lipopolysaccharide to determine T cell proliferation, cytokine production, and CD4⁺ T cell subpopulations.

Results

Compared to HFD control group, all CR mice, regardless of the presence of curcumin and/or piperine, had lower body weight and fat mass, lower levels of blood glucose and insulin, and fewer total spleen cells but a higher percentage of CD4⁺ T cells. Additionally, they demonstrated lower production of pro-inflammatory cytokines IL-1β and TNF-α, a trend toward lower IL-6, and lower production of PGE₂, a lipid molecule with pro-inflammatory and T cell-suppressive properties. Mice with CR alone had higher splenocyte proliferation and IL-2 production, but this effect of CR was diminished by spice supplementation. CR alone or in combination with spice supplementation had no effect on production of cytokines IL-4, IL-10, IFN-γ, and IL-17, or the proportion of different CD4⁺ T cell subsets.

Conclusion

CR on an HFD favorably impacts both metabolic and immune/inflammatory profiles; however, the presence of curcumin and/or piperine does not amplify CR’s beneficial effects.

Inhibition of L-type Ca(2+) channels by curcumin requires a novel protein kinase-theta isoform in rat hippocampal neurons

Curcumin, a major active compound of Curcuma longa, has been reported to have potent neuroprotective activities. However to date, the relevant mechanisms still remain unclear. In this study, we report that curcumin selectively inhibits L-type Ca(2+) channel currents in cultured rat hippocampal neurons. Whole-cell currents were recorded using 10mM barium as a charge carrier. Curcumin reversibly inhibited high-voltage-gated Ca(2+) channel (HVGCC) currents (IBa) in a concentration-dependent manner but had no apparent effects on the cells treated with nifedipine, a specific L-type Ca(2+) channel blocker. Curcumin did not markedly affect the activation of L-type Ca(2+) channels while significantly shifted the inactivation curve in the hyperpolarizing direction. Pretreatment of cells with the classical and novel PKC antagonists GF109203X and calphostin C completely abolished curcumin-induced IBa inhibition, whereas the classical PKC antagonist Gö6976 or inhibition of PKA activity elicited no such effects. Moreover, the curcumin-induced IBa response was abolished by intracellular application of the PKC-θ inhibitory peptide PKC-θ-IP or by siRNA knockdown of PKC-θ in cultured rat hippocampal neurons. In these neurons, novel isoforms of PKC including delta (PKC-δ), epsilon (PKC-ɛ) and theta (PKC-θ), but not eta (PKC-η), were endogenously expressed. Taken together, these results suggest that curcumin selectively inhibits IBavia a novel PKC-θ-dependent pathway, which could contribute to its neuroprotective effects in rat hippocampal neurons.