Suberosin inhibits proliferation of human peripheral blood mononuclear cells through the modulation of the transcription factors NF-AT and NF-kappaB

A Review of the Ethnobotanical Use, Chemistry and Pharmacological Activities of Constituents Derived from the Plant Genus Geijera (Rutaceae)

Geijera Schott is a plant genus of the Rutaceae Juss. (rue and citrus) family, comprising six species which are all native to Oceania. Of the plants belonging to this genus, the most significant species that has a customary use is Geijera parviflora, which was used by Indigenous Australians, primarily as a pain reliever. Herein, a comprehensive review of the literature published on the genus Geijera from 1930 to 2023 was conducted. This is the first review for this plant genus, and it highlights the chemical constituents reported to date, together with the range of pharmacological properties described from the various species and different parts of the plant. These properties include anti-inflammatory, anti-microbial, anti-parasitic, insect repellent, analgesic, neuroactive, and anti-cancer activities. Finally, a reflection on some of the important areas for future focused studies of this plant genus is provided.

Low levels of CD26 on certain cellular subtypes of donor harvest is associated with better clinical outcomes post allogeneic stem cell transplantation through regulation of NF-κB pathway and pro-inflammatory cytokines

BACKGROUND

We had previously reported significant association of immunoectoenzyme CD26 expression on donor harvest with acute Graft-versus-Host-Disease (aGVHD) in allogeneic stem cell transplantation (ASCT) patients. The current study was aimed at analysing CD26 signaling pathway molecules and understanding their impact on immune reconstitution and clinical outcomes post-ASCT.

SUBJECTS AND METHODOLOGY

The study cohort included 26 transplant donors/patients who underwent reduced intensity (n = 21), myeloablative (n = 4) and non-myeloablative (n = 1) ASCT for hematological malignancies. Donors were matched related donors (n = 19) and haploidentical donors (n = 7). Surface expression of CD26, CD73 and ADA, and various immune cell subtypes were assessed by multicolour-flow cytometry. Soluble CD26 (sCD26) and cytokine levels were measured in plasma samples by ELISA and Multiplex Luminex assay, respectively. Immune cells from healthy individuals were stimulated with phytohemagglutinin (PHA) in the presence or absence of CD26 inhibitor. Effect of CD26 inhibition on NF-κB localization in PHA stimulated cells was analysed by immunofluorescence and confocal microscopy. Pro-inflammatory cytokines from the culture supernatants were detected with Cytometric bead array flow cytometry. Association of all measured markers with clinical outcomes was evaluated using appropriate statistical tests.

RESULTS

CD26 surface expression on PBSC donor harvest cells showed increased risk of chronic GVHD (cGVHD, p = 0.055). Amongst the various immune cell subtypes, decreased B cells in harvest showed significant association with aGVHD (p = 0.022) whereas increased myeloid dendritic cells and CD3+T cells at Day100 in peripheral blood of transplant recipients correlated with cGVHD (p = 0.046) and aGVHD (p = 0.035), respectively. Further, high sCD26 in transplant recipients at Day100 exhibited association with reduced event-free survival (EFS) (p = 0.011). Higher CD26 expression on more & less mature NK cells, naïve & post-switched memory B cells and Treg cells in the donor harvest (p < 0.05) led to lower EFS in transplant recipients. Mechanistically, CD26 inhibitor caused dose-dependent reduction in CD26 enzyme activity and in pro-inflammatory cytokine production in post mitogen-stimulated T cell cultures.

CONCLUSION

Our study has implicated that lower CD26 expression on immune cell subtypes of the donor stem cell harvest is associated with reduced risk of GVHD and better survival. The underlying mechanism was found to be through NF-κB pathway and pro-inflammatory cytokines. Based on these observations, chemically designed or natural resources-based CD26 inhibitors can be explored further in clinical trials for improving ASCT outcomes.

Upregulation of Inflammatory Mediators in Peripheral Blood CD40+ Cells in Children with Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a common and severe neurodevelopmental disorder in early childhood, defined as social and communication deficits and repetitive and stereotypic behaviours. The aetiology is unknown in most cases. However, several studies have identified immune dysregulation as potentially promoting ASD. Among the numerous immunological findings in ASD, reports of increased pro-inflammatory markers remain the most consistently observed. C-C chemokine receptor type 1 (CCR1) activation is pro-inflammatory in several neurological disorders. Previous evidence has implied that the expression of chemokine receptors, inflammatory mediators, and transcription factors play a pivotal role in several neuroinflammatory disorders. There have also been reports on the association between increased levels of proinflammatory cytokines and ASD. In this study, we aimed to investigate the possible involvement of CCR1, inflammatory mediators, and transcription factor expression in CD40⁺ cells in ASD compared to typically developing controls (TDC). Flow cytometry analysis was used to determine the levels of CCR1-, IFN-γ-, T-box transcription factor (T-bet-), IL-17A-, retinoid-related orphan receptor gamma t (RORγt-), IL-22- and TNF-α-expressing CD40 cells in PBMCs in children with ASD and the TDC group. We further examined the mRNA and protein expression levels of CCR1 using real-time PCR and western blot analysis. Our results revealed that children with ASD had significantly increased numbers of CD40⁺CCR1⁺, CD40⁺IFN-γ⁺, CD40⁺T-bet⁺, CD40⁺IL-17A⁺, CD40⁺RORγt⁺, CD4⁺IL-22⁺, and CD40⁺TNF-α⁺ cells compared with the TDC group. Furthermore, children with ASD had higher CCR1 mRNA and protein expression levels than those in the TDC group. These results indicate that CCR1, inflammatory mediators, and transcription factors expressed in CD40 cells play vital roles in disease progression.

Identification of suberosin metabolites in human liver microsomes by high-performance liquid chromatography combined with high-resolution quadrupole-orbitrap mass spectrometer

Suberosin is a natural prenylated coumarin derivative isolated from Citropsis articulata. It has various pharmacological properties, especially as an anticoagulant, for which it has been used since antiquity. However, its metabolic pathway and metabolites have not yet been studied. Therefore, this study characterizes its metabolic pathway and metabolites in human liver microsomes (HLMs) using high-resolution quadrupole-orbitrap mass spectrometry (HRMS/MS). Eight metabolites (M1-M8) were found, including three monohydroxylated (M1-M3), one hydrated (M4), three dihydroxylated (M5-M7), and one glucuronide conjugate (M8). Furthermore, forms of cytochrome P450 (CYPs) responsible for suberosin metabolism in HLMs were characterized. CYP1A2 was identified as a major enzyme for the production of M1 and M5 metabolites. The M2, M3, and M7 metabolites were predominantly generated by CYP2B6. M8 was the only phase II metabolite, identified as a glucuronide conjugate from either M1 or M2. This glucuronide conjugate may be the only promising metabolite from phase II metabolism. Phase I metabolism, especially hydroxylation, was found to provide a predominant metabolic pathway of suberosin in HLMs. Further studies should be conducted to explore the metabolites, examining their efficacy and their toxicity in an in vivo system.

Suberosin Attenuates the Proliferation of MCF-7 Breast Cancer Cells in Combination with Radiotherapy or Hyperthermia

AIM

The aim of this study was to determine the proliferation of MCF-7 following irradiation or hyperthermia as alone or pre-treatment with suberosin.

BACKGROUND

Radiotherapy is a major therapeutic modality for the control of breast cancer. However, hyperthermia can be prescribed for relief of pain or enhancing cancer cell death. Some studies have attempted its use as an adjuvant to improve therapeutic efficiency. Suberosin is a cumarin- derived natural agent that has shown anti-inflammatory properties.

OBJECTIVE

In this in vitro study, possible sensitization effect of suberosin in combination with radiation or hyperthermia was evaluated.

METHODS

MCF-7 breast cancer cells were irradiated or received hyperthermia with or without treatment with suberosin. The incidence of apoptosis as well as viability of MCF-7 cells were observed. Furthermore, the expressions of pro-apoptotic genes such as Bax, Bcl-2, and some caspases were evaluated using real-time PCR.

RESULTS

Both radiotherapy or hyperthermia reduced the proliferation of MCF-7 cells. Suberosin amplified the effects of radiotherapy or hyperthermia for induction of pro-apoptotic genes and reducing cell viability.

CONCLUSION

Suberosin has a potent anti-cancer effect when combined with radiotherapy or hyperthermia. It could be a potential candidate for killing breast cancer cells as well as increasing the therapeutic efficiency of radiotherapy or hyperthermia.

Upregulation of interleukin (IL)-31, a cytokine producing CXCR1 peripheral immune cells, contributes to the immune abnormalities of autism spectrum disorder

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders characterized by communication deficits, impaired social interactions, and restricted stereotypical behaviors. Several immune cells are associated with immune dysfunction in ASD; however, IL-31 has not been explored in ASD. This study aims to investigate the role of inflammatory cytokines and transcription factors of the CXCR1 cells in children with ASD. In the current study, we investigated the cytokines and transcription factors produced by CXCR1⁺ cells (IL-31, IL-9, IL-21R, IL-21, NF-κB p65, RORγT, STAT1, and FoxP3) in peripheral blood mononuclear cells (PBMCs), from children with ASD and typically developing (TD) control children, using flow cytometric analysis. In addition, we measured mRNA and protein expression levels of IL-31 using quantitative real-time PCR and western blot analyses in PBMCs. In our study, children with ASD had increased CXCR1⁺IL-31⁺, CXCR1⁺IL-9⁺, CXCR1⁺IL-21R⁺, CXCR1⁺IL-21⁺, CXCR1⁺NF-κB⁺ p65, CXCR1⁺RORγT⁺, and CXCR1⁺STAT1⁺, and decreased CXCR1⁺FoxP3⁺ cells as compared with cells from the TD control samples. Similarly, children with ASD showed increased IL-31 mRNA and protein expression levels as compared to those of TD control samples. Our results suggest that upregulated production of inflammatory cytokines and transcription factors in CXCR1⁺ cells cause immunological imbalance in children with ASD. Therefore, attenuation of inflammatory cytokines/mediators and transcription factors could have a therapeutic potential in the treatment of ASD.

Involvement of CD45 cells in the development of autism spectrum disorder through dysregulation of granulocyte-macrophage colony-stimulating factor, key inflammatory cytokines, and transcription factors

Autismspectrum disorder (ASD) is a complex and multifactorial heterogeneous disorder. Previous investigations have revealed the association between the immune system and ASD, which is characterized by impaired communication skills. Inflammatory response through CD45 cells plays a key role in the pathogenesis of several autoimmune disorders; however, the molecular mechanism of CD45 cells in ASD is not clearly defined.In this study, we investigated the role of CD45 signaling in children with ASD. In this study, we aimed to investigate the possible involvement of CD45 cells expressing granulocyte-macrophage colony-stimulating factor and inflammatory transcription factors in ASD. Flow cytometric analysis, using peripheral blood mononuclear cells (PBMC), revealed the numbers of GM-CSF-, IFN-γ-, IL-6-, IL-9-, IL-22-, T-bet-, pStat3-, Helios-, and Stat6-producing CD45⁺ cells in children with ASD and children in the control group. We further evaluated the mRNA and protein expression levels of GM-CSF in PBMC by RT-PCR and western blotting analysis. Our results revealed that the children with ASD exhibited significantly higher numbers of CD45⁺GM-CSF⁺, CD45⁺IFN-γ⁺, CD45⁺IL-6⁺, CD45⁺IL-9⁺, CD45⁺IL-22⁺, CD45⁺T-bet⁺, and CD45⁺pStat3⁺ cells compared with the control group. We also found that the children with ASD showed a lower number of CD45⁺Helios⁺ and CD45⁺Stat6⁺ cells compared with the control group. Furthermore, the children with ASD showed higher GM-CSF mRNA and protein expression levels compared with the control group. These results indicated that CD45 could play an essential role in the immune abnormalities of ASD. Further investigation of the role of CD45 in neurodevelopment in ASD is warranted.

Elevated IL-16 expression is associated with development of immune dysfunction in children with autism

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairments in communication skills and social behaviors. Several studies have suggested that neuroimmune dysfunction plays a significant role in the pathogenesis of ASD; however, its exact etiology is unknown. Interleukin-16 (IL-16), a chemoattractant, is associated with various inflammatory processes. However, its role in children with ASD is unclear. This study aimed to investigate whether IL-16 expression is associated with immune dysfunction in children with ASD. We examined IL-16 expression in CD4⁺, CD8⁺, CD14⁺, CCR3⁺, and CXCR7⁺ cells in typically developing (TD) controls and children with ASD using flow cytometry in peripheral blood mononuclear cells (PBMCs). We also investigated the expression of IL-1β⁺IL-16⁺, IL-6⁺IL-16⁺, and TNF-α⁺IL-16⁺ in TD controls and children with ASD. We further explored IL-16 mRNA and protein expression using RT-PCR and western blotting. CD4⁺IL-16⁺, CD8⁺IL-16⁺, CD14⁺IL-16⁺, CCR3⁺IL-16⁺, and CXCR7⁺IL-16⁺ cells increased significantly in children with ASD compared with TD controls. We also showed that expression of IL-1β⁺IL-16⁺, IL-6⁺IL-16⁺, and TNF-α⁺IL-16⁺ was elevated in children with ASD compared with TD controls. Moreover, IL-16 mRNA and protein expression was significantly induced in children with ASD compared with TD controls. These results suggest that IL-16 expression could play an essential role in immune alteration in children with ASD.

Dysregulation of the expression of HLA-DR, costimulatory molecule, and chemokine receptors on immune cells in children with autism

Autism spectrum disorder (ASD) is a heterogeneous disorder diagnosed based on the severity of abnormalities in social skills. Several studies have acknowledged the presence of abnormal immune functions among individuals diagnosed with ASD. HLA-DR (human leukocyte antigen-antigen D related) has been shown to play a significant role in several inflammatory and neurological disorders; however, the role of HLA-DR signaling in ASD has not yet been fully clarified. In this study, we investigated the role of HLA-DR signaling in children with ASD. Flow cytometric analysis, using peripheral blood mononuclear cells (PBMCs), revealed the numbers of CD4⁺, CD8⁺, CD28⁺, CXCR4⁺, and CCR7⁺ expressing HLA-DR cells in typically developing (TD) controls and children with ASD. We also determined the numbers of IFN-γ⁺, IL-21⁺, and Foxp3⁺ expressing HLA-DR cells in TD controls and in children with ASD using PBMCs. We observed mRNA and protein expression levels of HLA-DR by RT-PCR and western blotting analysis. Our results revealed that children with ASD had significantly increased numbers of HLA-DR⁺CD4⁺, HLA-DR⁺CD8⁺, CD28⁺HLA-DR⁺, HLA-DR⁺CXCR4⁺, HLA-DR⁺CCR7⁺ cells compared with TD controls. We found that children with ASD showed increased HLA-DR⁺IFN-γ⁺ and HLA-DR⁺IL-21⁺ and decreased HLA-DR⁺Foxp3⁺ expression levels compared with TD controls. Furthermore, children with ASD showed higher HLA-DR mRNA and protein expression levels compared with TD controls. These results indicated that HLA-DR could play an essential role in the immune abnormalities associated with ASD.

Downregulation in Helios transcription factor signaling is associated with immune dysfunction in blood leukocytes of autistic children

Autism spectrum disorder (ASD) is a complex heterogeneous neurodevelopmental disorder in which immunological imbalance has been suggested to be a major etiological component. Helios, a transcription factor, has been studied extensively in the context of human T cell regulation in health and disease, yet the role of Helios signaling has not been examined in children with ASD. In the present study, we investigated the production of Helios in CD4⁺, CD8⁺, and TIM-3⁺, CXCR3⁺ cells in typically developing (TD) controls and children with ASD and in peripheral blood mononuclear cells (PBMCs). We assayed the production of IFN-γ⁺Helios⁺, IL-21⁺Helios⁺, T-bet⁺Helios⁺, and Foxp3⁺Helios⁺ cells, and determined Helios mRNA and protein expression levels in PBMCs, in TD controls and children with ASD. Our results revealed that children with ASD had lower numbers of CD4⁺Helios⁺ CD8⁺Helios⁺, TIM-3⁺Helios⁺, and CXCR3⁺Helios⁺ cells as compared to TD controls. Our results also showed that children with ASD had decreased IFN-γ⁺Helios⁺, IL-21⁺Helios⁺, T-bet⁺Helios⁺, and Helios⁺Foxp3⁺ production compared to that in TD controls. Moreover, our results indicated that children with ASD had lower Helios mRNA and protein expression levels compared to those in TD controls. These results suggest that the Helios transcription factor may be critical to immune alterations in children with ASD. Therefore, our results suggest that targeting Helios signaling might offer a strategy for developing ASD therapies.

Upregulation of IL-9 and JAK-STAT signaling pathway in children with autism

Autism spectrum disorder (ASD) gradually develops predominantly neurodevelopmental disorders, which are socially diagnosed in early childhood. Though the etiopathology of ASD is not clear, immune alteration has been suggested as autism's pathophysiological mechanism. Previous studies found that several cytokines and transcription factor activation pathways were significantly increased in ASD. IL-9 has been confirmed to play a significant role in the central nervous system (CNS). The aim of the present study was to investigate the understudied role of pro- and anti-inflammatory cytokines and the JAK-STAT signaling pathway in ASD. We examined the IL-1β, IL-4, IFN-γ, and IL-9 positive immunostaining in all cells, and CD4⁺ T cells, in ASD and normally developing control children (TD), on peripheral blood mononuclear cells (PBMCs), using flow cytometry. We explored PBMC mRNA expression levels for IL-1β, IL-4, IFN-γ, IL-9, JAK1, and STAT5, by using real-time PCR (RT-PCR). We also explored PBMC protein expression levels for IL-1β, IL-4, IL-9, pJAK1, and pSTAT5 by using western blotting. We found that the children with ASD had increased IL-1β, IL-4, IFN-γ, and IL-9 positive immunostaining in all cells, and in CD4⁺ cells, relative to the TD controls. The mRNA and protein expression for IL-1β, IL-4, IFN-γ, IL-9, JAK1, pJAK1, STAT5, and pSTAT5 were also significantly elevated in ASD relative to TD controls. These results suggested that cytokines and JAK-STAT activation signaling have an essential role in immune dysfunction in ASD.

Imbalance between the anti- and pro-inflammatory milieu in blood leukocytes of autistic children

Accumulating evidence suggests an association between immune dysfunction and autism disorders in a significant subset of children. In addition, an imbalance between pro- and anti-inflammatory pathways has been proposed to play an important role in the pathogenesis of several neurodevelopmental disorders including autism; however, the role of anti-inflammatory molecules IL-27 and CTLA-4 and pro-inflammatory cytokines IL-21 and IL-22 has not previously been explored in autistic children. In the current study, we investigated the expression of IL-21, IL-22, IL-27, and CD152 (CTLA-4) following an in-vitro immunological challenge of peripheral blood mononuclear cells (PBMCs) from children with autism (AU) or typically-developing children (TD) with phorbol-12-myristate 13-acetate (PMA) and ionomycin. In our study, cells from children with AU had increased IL-21 and IL-22 and decreased CTLA-4 expression on CD4+ T cells as compared with cells from the TD control. Similarly, AU cells showed decreased IL-27 production by CD14+ cells compared to that of TD control cells. These results were confirmed by real-time PCR and western blot analyses. Our study shows dysregulation of the immune balance in cells from autistic children as depicted by enhanced pro-inflammatory cytokines, 'IL-21/IL-22' and decreased anti-inflammatory molecules, 'IL-27/CTLA-4'. Thus, further study of this immune imbalance in autistic children is warranted in order to facilitate development of biomarkers and therapeutics.

Antileishmanial activity of prenylated coumarins isolated from Ferulago angulata and Prangos asperula

Leishmaniasis has a wide spectrum of signs and symptoms due to infection to numbers of Leishmania species and makes enormous mortality and morbidity. There are clues of antileishmanial effects of prenylated coumarins. Apiaceae family is one of the most important sources of coumarins. Air-dried aerial parts of Ferulago angulata and fruits of Prangos asperula were extracted with n-hexane, using a soxhlet apparatus. The solvents were evaporated under reduced pressure. Column chromatography and crystallization process resulted to isolation of three prenylated coumarins. ¹H-nuclear magnetic resonance, electron ionization Mass and Infrared spectra were used for elucidation of isolated compounds. Leishmanicidal activity of isolated coumarins was assessed on Leishmania major strain (MRHO/IR/75/ER) for the first time. Suberosin epoxide and suberosin were isolated from aerial parts of F. angulata and osthol was extracted from grounded fruits of P. asperula. Osthol showed a significant antileishmanial effect on promastigotes in early hours of exposure with IC₅₀ of 14.40 µg/mL but suberosin epoxide showed only a weak antileishmanial activity. IC₅₀ of osthol and suberosin epoxide after 48 h were 10.79 and 54.0 µg/mL, respectively. Suberosin showed no remarkable effect in these concentrations. This is the first report on the pharmacological activity of suberosin epoxide. Substantial difference between efficacies of two isomers, osthol and suberosin remarks the importance of prenyl substituent location on C-8.

Dysregulation of Th1, Th2, Th17, and T regulatory cell-related transcription factor signaling in children with autism

Autism is a neurodevelopmental disorder characterized by stereotypic repetitive behaviors, impaired social interactions, and communication deficits. Numerous immune system abnormalities have been described in individuals with autism including abnormalities in the ratio of Th1/Th2/Th17 cells; however, the expression of the transcription factors responsible for the regulation and differentiation of Th1/Th2/Th17/Treg cells has not previously been evaluated. Peripheral blood mononuclear cells (PBMCs) from children with autism (AU) or typically developing (TD) control children were stimulated with phorbol-12-myristate 13-acetate (PMA) and ionomycin in the presence of brefeldin A. The expressions of Foxp3, RORγt, STAT-3, T-bet, and GATA-3 mRNAs and proteins were then assessed. Our study shows that children with AU displayed altered immune profiles and function, characterized by a systemic deficit of Foxp3⁺ T regulatory (Treg) cells and increased RORγt⁺, T-bet⁺, GATA-3⁺, and production by CD4⁺ T cells as compared to TD. This was confirmed by real-time PCR (RT-PCR) and western blot analyses. Our results suggest that autism impacts transcription factor signaling, which results in an immunological imbalance. Therefore, the restoration of transcription factor signaling may have a great therapeutic potential in the treatment of autistic disorders.

Shikonin Suppresses Human T Lymphocyte Activation through Inhibition of IKK β Activity and JNK Phosphorylation

The key role of T cells has been elaborated in mediating immune responses and pathogenesis of human inflammatory and autoimmune conditions. In the current study the effect of shikonin, a compound isolated from a medicinal plant, on inhibition of T-cell activation was firstly examined by using primary human T lymphocytes isolated from buffy coat. Results showed that shikonin dose dependently suppressed T-cell proliferation, IL-2 and IFN-γ secretion, CD69 and CD25 expression, as well as cell cycle arrest activated by costimulation of PMA/ionomycin or OKT-3/CD28 monoclonal antibodies. Moreover, these inhibitory responses mediated by shikonin were found to be associated with suppression of the NF-κB signaling pathway via inhibition of the IKKα/β phosphorylation, IκB-α phosphorylation and degradation, and NF-κB nuclear translocation by directly decreasing IKKβ activity. Moreover, shikonin suppressed JNK phosphorylation in the MAPKs pathway of T cells. In this connection, we conclude that shikonin could suppress T lymphocyte activation through suppressing IKKβ activity and JNK signaling, which suggests that shikonin is valuable for further investigation as a potential immunosuppressive agent.

4-Hydroxy-17-methylincisterol from Agaricus blazei Decreased Cytokine Production and Cell Proliferation in Human Peripheral Blood Mononuclear Cells via Inhibition of NF-AT and NF-κB Activation

Agaricus blazei Murill is an edible and medicinal mushroom. In the previous study, we have proved that extracts of A. blazei inhibit human peripheral blood mononuclear cell (PBMC) proliferation activated with phytohemagglutinin (PHA). Currently, we purified 4-hydroxy-17-methylincisterol (4-HM; C21H33O3) from A. blazei investigated its regulatory effects on cytokine productions and cell proliferation of PBMC induced by PHA. The results indicated that 4-HM suppressed, in activated PBMC, the production and mRNA expression of interleukin-2 (IL-2), IL-4, tumor necrosis factor- α , and interferon- γ in a concentration-dependent manner. This inhibition was not related to cell viability. While 4-HM did not affect ERK phosphorylation and its downstream c-fos gene expression in PBMC induced by PHA, it decreased both NF-AT and NF- κ B activation. The upstream signaling of NF-AT and NF- κ B, intracellular calcium concentrations ([Ca(2+)]i), and protein kinase C theta (PKC θ ) activation in PHA-treated PBMC were reduced by 4-HM. The data demonstrated that the suppressant effects of 4-HM on cell proliferation in PBMC activated by PHA appeared to be mediated, at least in part, through inhibition of Ca(2+) mobilization and PKC θ activation, NF-AT and NF- κ B activation, and cytokine transcripts and productions of PBMC. We suggested that A. blazei contained a potential immunomodulator 4-HM.

Piperine inhibits cytokine production by human peripheral blood mononuclear cells

Piperine, an amide isolated from Piper species (Piperaceae), has been reported to exhibit central nervous system depression, anti-pyretic and anti-inflammatory activity. Immunomodulatory and anti-tumor activity of piperine has been demonstrated in mouse carcinomas. However, there is little information available concerning the effect of piperine on humans. We evaluated the immunopharmacological activity of this compound in human immune cells. Human peripheral blood mononuclear cells (PBMCs) were exposed to piperine, and cell proliferation was determined by the MTS assay. Piperine significantly inhibited phytohemagglutinin-stimulated human PBMC proliferation after exposure for 72 h. This compound inhibited PBMC activity, with an IC(50) of 100.73 ± 11.16 μg/mL. Production of interleukin-2 (IL-2) and interferon-γ (IFN-γ) was measured using an ELISA assay and RT-PCR. Piperine inhibited IL-2 and IFN-γ production in the PBMCs. RT-PCR data indicated that IL-2 and IFN-γ mRNA expression in PBMCs is suppressed by piperine. This compound significantly inhibited the production of these two cytokines by activated PBMCs in a dose-dependent manner. In conclusion, piperine appears to have potential as an immunomodulatory agent for immune system suppression.

Arctigenin from Arctium lappa inhibits interleukin-2 and interferon gene expression in primary human T lymphocytes

BACKGROUND

Arctium lappa (Niubang), a Chinese herbal medicine, is used to treat tissue inflammation. This study investigates the effects of arctigenin (AC), isolated from A. lappa, on anti-CD3/CD28 Ab-stimulated cell proliferation and cytokine gene expression in primary human T lymphocytes.

METHODS

Cell proliferation was determined with enzyme immunoassays and the tritiated thymidine uptake method. Cytokine production and gene expression were analyzed with reverse transcription-polymerase chain reaction.

RESULTS

AC inhibited primary human T lymphocytes proliferation activated by anti-CD3/CD28 Ab. Cell viability test indicated that the inhibitory effects of AC on primary human T lymphocyte proliferation were not due to direct cytotoxicity. AC suppressed interleukin-2 (IL-2) and interferon-γ (IFN-γ) production in a concentration-dependent manner. Furthermore, AC decreased the IL-2 and IFN-γ gene expression in primary human T lymphocytes induced by anti-CD3/CD28 Ab. Reporter gene analyses revealed that AC decreased NF-AT-mediated reporter gene expression.

CONCLUSION

AC inhibited T lymphocyte proliferation and decreased the gene expression of IL-2, IFN-γ and NF-AT.

Characterized polysaccharides from black soybean induce granulocyte colony-stimulated factor gene expression in a phosphoinositide 3-kinase-dependent manner

Black soybean (Glycine max L. merr.) is an edible Chinese medicine for nourishment spleen. In the present study, effects of characterized polysaccharides from black soybean (PGM) on granulocyte colony-stimulated factor (G-CSF) production in human peripheral blood mononuclear cells (PBMC) were determined and their action mechanisms were examined. The results indicated that PGM concentration-dependently enhanced G-CSF production in PBMC through modulation of mRNA expression. Data from Western blotting showed that PGM significantly induced the extracellular signal-regulated protein kinase (ERK) activation in PBMC. The nuclear factor (NF)-κB activation in PBMC was increased with PGM by modulation of IκB degradation and PKC θ activation. The levels of G-CSF mRNA in PGM-treated PBMC could be reduced by ERK inhibitor U0126 and NF-κB inhibitor pyrrolidine dithiocarbamate, respectively. Furthermore, the data showed that PGM stimulated phosphoinositide 3-kinase (PI3K)-regulated Akt phosphorylation. The PI3K inhibitor, Ly294002, blocked ERK, NF-κB, and PKC θ activation and G-CSF mRNA expression in PBMC induced by PGM. Thus, we first proved that the enhancement mechanisms of PGM on G-CSF production, appeared to be mediated, at least in part, through activation of PI3K, ERK, PKC θ, and NF-κB signaling pathways in PBMC. We suggest that PGM from black soybean is a potential G-CSF stimulator.

FIP-fve stimulates interferon-gamma production via modulation of calcium release and PKC-alpha activation

Fungal immunomodulatory protein, FIP-fve, has been isolated from Flammulina velutipes, and its immunomodulatory effects are believed to be associated with the enhanced activation of IFN-gamma-releasing Th1 cells. However, the mechanisms of FIP-fve-mediated signal transduction in the regulation of interferon-gamma (IFN-gamma) gene expression in human peripheral blood mononuclear cells (PBMCs) are still poorly understood. Using fluo-3 AM, we found that FIP-fve induces a rapid elevation in calcium concentration. ELISA, RT-PCR and Western blot assays demonstrated significant increases in the production and mRNA expression of IFN-gamma and protein kinase C-alpha (PKC-alpha) activation in activated PBMCs, which were abolished by EGTA, nifedipine and GO6976. In conclusion, Ca2+ release and PKC-alpha activation are required for IFN-gamma production induced by FIP-fve in PBMCs.

A new synthetic compound, 2-OH, enhances interleukin-2 and interferon-gamma gene expression in human peripheral blood mononuclear cells

A new synthetic compound, 6-hydroxy-2-tosylisoquinolin-1(2H)-one (2-OH), was selected for immunopharmacological activity tests. The effects of 2-OH on human peripheral blood mononuclear cell (PBMC) proliferation were determined by tritiated thymidine uptake. Compared to phytohemagglutinin (PHA; 5 μg/mL) stimulation, 2-OH significantly enhanced PBMC proliferation in a dose-dependent manner. The 50% enhancement activity (EC₅₀) for 2-OH was 4.4±0.1 μM. In addition, effects of 2-OH on interleukin-2 (IL-2) and interferon-γ (IFN-γ) production in PBMC were determined by enzyme immunoassay. Results demonstrated that 2-OH stimulated IL-2 and IFN-γ production in PBMC. Data from reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR indicated that IL-2 and IFN-γ mRNA expression in PBMC could be induced by 2-OH. Therefore, 2-OH enhanced IL-2 and IFN-γ production in PBMC by modulation their gene expression. We suggest that 2-OH may be an immunomodulatory agent.

Isolation and immunomodulatory effect of homoisoflavones and flavones from Agave sisalana Perrine ex Engelm

Three known flavones and seven known homoisoflavonoids were isolated from the methanolic extract of the leaves of Agave sisalanaPerrine ex Engelm. Their structures were elucidated on the basis of spectroscopic analysis. The isolated compounds were also evaluated for immunopharmacological activity. PBMC were used as target cells, and cell proliferation was determined by (3)H-thymidine uptake. (+/-)-3,9-Dihydroeucomin (4), dihydrobonducellin (5), and 5,7-dihydroxy-3-(4'-hydroxybenzyl)-4-chromanone (7) showed inhibitory effects on PBMC proliferation activated by PHA with IC(50) values 19.4, 73.8, and 58.8 microM, respectively. All three compounds significantly inhibited the production of IL-2 and IFN-gamma in activated PBMC in a concentration-dependent manner.

Norcantharidin reduced cyclins and cytokines production in human peripheral blood mononuclear cells

AIMS

To evaluate potential agents of therapeutic value in tissue inflammation, we studied norcantharidin (NCTD) and its derivatives for their effects on immune responses of human peripheral blood mononuclear cells (PBMC) in vitro.

MAIN METHODS

PBMC proliferation was evaluated by tritiated thymidine uptake method. The production and gene expression of cytokines were determined with enzyme immunoassays (EIA) and reverse transcription-polymerase chain reaction (RT-PCR), respectively.

KEY FINDINGS

Five derivatives from NCTD had no significant effect on cell proliferation in PBMC. NCTD inhibited PBMC proliferation induced by phytohemagglutinin (PHA) with a 50% inhibitory concentration (IC(50)) 42.1+/-2.3 microM. The inhibitory action of NCTD did not involve direct cytotoxicity. To localize the point in the PBMC proliferation where arrest occurred, a set of key regulatory events leading to the cell proliferation, including cell cycle progression, production and gene expression of interleukin-2 (IL-2), IL-4, IL-10, and interferon-gamma (IFN-gamma) and cyclins was examined. Data demonstrated NCTD arrested the cell cycle progression of activated PBMC from the G1 transition to the S phase. The cyclin D3, E, A, and B transcripts and protein production in PHA-treated PBMC was reduced by NCTD. Whereas NCTD exerted no effect on IL-4 and IFN-gamma production, it significantly alleviated the production and mRNA expression of IL-2 and IL-10 in activated PBMC.

SIGNIFICANCE

The suppressant effects of NCTD on proliferation of PBMC activated by PHA therefore appear to be mediated, at least in part, through inhibition of cyclins and IL-2 production and arrest of cell cycle progression in the cells.

Bioactive marine prostanoids from octocoral Clavularia viridis

Chemical investigation of the nonpolar extract of soft coral Clavularia viridis resulted in isolation of five new prostanoids, designated as claviridic acids A-E (1-5, resp.), in addition to the known clavulones I-III. Their structures were determined on the basis of spectroscopic techniques, especially HR-ESI-MS, CD, and 2D-NMR experiments. The isolated marine prostanoids exhibited potent inhibitory effect on PHA-induced proliferation of peripheral blood mononuclear cells (PBMC), as well as significant cytotoxic activity against human gastric cancer cells (AGS).

Tanshinlactone A from Salvia miltiorrhiza modulates interleukin-2 and interferon-gamma gene expression

Salvia miltiorrhiza Bunge (Tanshen), a traditional Chinese herbal medicine, is popularly used to treat cardiovascular disorders. In the present study, effects of tanshinlactone A (C(16)H(12)O(4); M.W. 268), newly discovered from Salvia miltiorrhiza, on phytohemagglutinin (PHA)-stimulated cell proliferation were investigated in human peripheral blood mononuclear cells (PBMC). The results indicated that tanshinlactone A inhibited PBMC proliferation activated with PHA with an IC(50) of 15.6+/-1.9 microM. Cell viability test indicated that inhibitory effects of tanshinlactone A on PBMC proliferation were not through direct cytotoxicity. Furthermore, tanshinlactone A significantly decreased the interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) gene expression in PHA-activated PBMC. It reduced the phosphorylation of mitogen-activated protein kinases (MAPK) involving extracellular signal-regulated protein kinase (ERK), P38, and c-Jun NH(2)-terminal kinase (JNK) in PHA-treated PBMC. We suggested that the inhibitory effects of tanshinlactone A on PHA-induced PBMC proliferation, appeared to be mediated, at least in part, through reduction of MAPK activation and IL-2 and IFN-gamma production. Therefore, data demonstrate for the first time that tanshinlactone A is likely an immunomodulatory agent for PBMC.