Jinhee Cho

Acidic polysaccharide of Panax ginseng regulates the mitochondria/caspase-dependent apoptotic pathway in radiation-induced damage to the jejunum in mice

Owing to its susceptibility to radiation, the small intestine of mice is valuable for studying radioprotective effects. When exposed to radiation, intestinal crypt cells immediately go through apoptosis, which impairs swift differentiation necessary for the regeneration of intestinal villi. Our previous studies have elucidated that acidic polysaccharide of Panax ginseng (APG) protects the mouse small intestine from radiation-induced damage by lengthening villi with proliferation and repopulation of crypt cells. In the present study, we identified the molecular mechanism involved. C57BL/6 mice were irradiated with gamma-rays with or without APG and the expression levels of apoptosis-related molecules in the jejunum were investigated using immunohistochemistry. APG pretreatment strongly decreased the radiation-induced apoptosis in the jejunum. It increased the expression levels of anti-apoptotic proteins (Bcl-2 and Bcl-XS/L) and dramatically reduced the expression levels of pro-apoptotic proteins (p53, BAX, cytochrome c and caspase-3). Therefore, APG attenuated the apoptosis through the intrinsic pathway, which is controlled by p53 and Bcl-2 family members. Results presented in this study suggest that APG protects the mouse small intestine from irradiation-induced apoptosis through inhibition of the p53-dependent pathway and the mitochondria/caspase pathway. Thus, APG may be a potential agent for preventing radiation induced injuries in intestinal cells during radio-therapy such as in cancer treatment.

Phloroglucinol protects small intestines of mice from ionizing radiation by regulating apoptosis-related molecules: a comparative immunohistochemical study.

Phloroglucinol (PG) is a phenolic compound isolated from Ecklonia cava, a brown algae abundant on Jeju island, Korea. Previous reports have suggested that PG exerts antioxidative and cytoprotective effects against oxidative stress. In this study, we confirmed that PG protected against small intestinal damage caused by ionizing radiation, and we investigated its protective mechanism in detail. Regeneration of intestinal crypts in the PG-treated irradiated group was significantly promoted compared with that in irradiated controls. The expression level of proapoptotic molecules such as p53, Bax, and Bak in the small intestine was downregulated and that of antiapoptotic molecules such as Bcl-2 and Bcl-XS/L was augmented in the PG-treated group. On histological observation of the small intestine, PG inhibited the immunoreactivity of p53, Bax, and Bak and increased that of Bcl-2 and Bcl-XS/L. These results demonstrate the protective mechanisms of PG in mice against intestinal damage from ionizing radiation, providing the benefit of raising the apoptosis threshold of jejunal crypt cells.

Blocking Glutamate Carboxypeptidase II Inhibits Glutamate Excitotoxicity and Regulates Immune Responses in Experimental Autoimmune Encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease in the murine central nervous system (CNS) and recapitulates the clinical and pathological features of human multiple sclerosis (MS). Glutamate carboxipeptidase II (GCPII), an enzyme expressed exclusively on astrocytes, is known to affect the disease progression of various neurological disorders by producing glutamate. Despite several findings indicating possible link between glutamate and MS/EAE, however, the involvement of astrocyte or GCPII on glutamate excitotoxicity has not received much attention in MS/EAE. When we examined GCPII expression during EAE progression in this study, we observed significantly elevated GCPII expression in peak stage of disease localized mainly in astrocytes. Intrigued by these results, we tried a potent GCPII inhibitor, 2‐phosphonomethyl pentanedioic acid (2‐PMPA), on EAE mice and noticed markedly attenuated EAE clinical signs along with significantly inhibited infiltration of inflammatory cells into CNS. Furthermore, 2‐PMPA dampened the function of Th1 cell lineage and down‐regulated mGluR1 expression in both periphery and CNS contributing to glutamate‐mediated immune regulation. Our observations identify a sequence of events triggering EAE through GCPII overexpression, which may offer a novel therapeutic approach to the treatment of MS.

Beetroot (Beta vulgaris) rescues mice from γ-ray irradiation by accelerating hematopoiesis and curtailing immunosuppression

Abstract Context: Beetroot [Beta vulgaris Linné (Chenopodiaceae)], a vegetable usually consumed as a food or a medicinal plant in Europe, has been reported to have antioxidant and anti-inflammatory properties. Since the lymphohematopoietic system is the most sensitive tissue to ionizing radiation, protecting it from radiation damage is one of the best ways to decrease detrimental effects from radiation exposure. Objective: In this study, we evaluated the radio-protective effects of beetroot in hematopoietic stem cells (HSCs) and progenitor cells. Materials and methods: Beetroot extract was administered at a dose of 400 mg/mouse per os (p.o.) three times into C57BL/6 mice and, at day 10 after γ-ray irradiation, diverse molecular presentations were measured and compared against non-irradiated and irradiated mice with PBS treatments. Survival of beetroot-fed and unfed irradiated animal was also compared. Results: Beetroot not only stimulated cell proliferation, but also minimized DNA damage of splenocytes. Beetroot also repopulated S-phase cells and increased Ki-67 or c-Kit positive cells in bone marrow. Moreover, beetroot-treated mice showed notable boosting of differentiation of HSCs into burst-forming units-erythroid along with increased production of IL-3. Also, beetroot-treated mice displayed enhancement in the level of hematocrit and hemoglobin as well as the number of red blood cell in peripheral blood. Beetroot diet improved survival rate of lethally exposed mice with a dose reduction factor (DRF) of 1.1. Discussion and conclusion: These results suggest that beetroot has the potency to preserve bone marrow integrity and stimulate the differentiation of HSCs against ionizing radiation.

Anti-inflammatory activities of Dangyuja (Citrus grandis Osbeck) in concanavalin A stimulated murine splenocytes and 12-O-tetradecanoylphorbol-13-acetate-induced murine skin edema

Dangyuja (Citrus grandis Osbeck), a citrus cultivated in southern Korea, has been used in traditional medicine for its anti-inflammatory effect. In this study, we investigated the anti-inflammatory potential of extract of Citrus grandis Osbeck (ECGO). In in vitro assays, ECGO treatment of concanavalin A (10μg/ml, for 24h) stimulated splenocytes showed significant reduction in CD44/CD62L+ T cell population and a marked decrease in the production of inflammatory cytokines IL-2, IFN-γ and IL-4. Interestingly, in vivo assays of ECGO topical treatment (100μg/20μl/ear) significantly mitigated the TPA (4μg/20μl/ear) induced edema induction and Myeloperoxidase activity. Anti-inflammatory potential of ECGO were further evidenced through its potent decrease in expression of inducible nitric oxide, cyclooxygenase-2, IL-1β and TNF-α and suppressed homing of CD3+ T cells and F4/80+ macrophages to site of inflammation. This study emphasizes the possibility of developing ECGO as an alternative natural topical agent to combat inflammatory diseases.

Galectin isolated from parasite inhibits remission of experimental autoimmune encephalomyelitis by up-regulating autoantibody.

Recently, parasite infections or parasite‐derived products have been suggested as a therapeutic strategy with suppression of immunopathology, which involves the induction of regulatory T cells or/and T helper type 2 (Th2) responses. In a recent study, researchers reported that constructed recombinant galectin (rTl‐gal) isolated from an adult worm of the gastrointestinal nematode parasite Toxascaris leonina attenuated clinical symptoms of inflammatory bowel disease in mice treated with dextran sulphate sodium. Noting the role of rTl‐gal in inflammatory disease, we attempted to investigate the effect of the parasite via its rTl‐gal on neuronal autoimmune disease using experimental autoimmune encephalomyelitis (EAE), a mouse inflammatory and demyelinating autoimmune disease model of human multiple sclerosis. In this model, rTl‐gal‐treated experimental autoimmune encephalomyelitis (EAE) mice failed to recover after the peak of the disease, leading to persistent central nervous system (CNS) damage, such as demyelination, gliosis and axonal damage. Further, rTl‐gal‐treated EAE mice markedly increased the number of CD45R/B220+ B cells in both infiltrated inflammation and the periphery, along with the increased production of autoantibody [anti‐myelin oligodendrocyte glycoprotein (MOG)35–55] in serum at chronic stage. Upon antigen restimulation, rTl‐gal treatment affected the release of overall cytokines, especially interferon (IFN)‐γ and tumour necrosis factor (TNF)‐α. Our results suggest that galectin isolated from a gastrointestinal parasite can deliver a harmful effect to EAE contrary to its beneficial effect on inflammatory bowel disease.

Geraniin Promotes Recovery of Hematopoietic Cells after Radiation Injury

Cells of the hematopoietic system are uniquely radiosensitive due to their rapid proliferation. Consequently, immune suppression readily and undesirably results from irradiation. Our previous studies demonstrated that geraniin isolated from Nymphaea tetragona var. angusta (water lily) had a protective effect on the splenocytes and intestinal tract of irradiated mice. This study was designed to assess the effectiveness of geraniin, an ellagitannin isolated from the water lily, in decreasing gamma ray irradiation-induced destruction of the hematopoietic system in mice. Geraniin treatment improved the survival time of bone marrow cells and maintained bone marrow integrity and also up-regulated the expression of stem cell receptors and the extent of cell mitosis. Geraniin also enhanced the proliferation and differentiation of immune cells that had been suppressed by irradiation. These results suggest geraniin is a promising agent for reconstituting hematopoietic cells after exposure to irradiation.

Potential involvement of glycogen synthase kinase (GSK)-3β in a rat model of multiple sclerosis: evidenced by lithium treatment

Glycogen synthase kinase (GSK)-3β has been known as a pro-inflammatory molecule in neuroinflammation. The involvement of GSK-3β remains unsolved in acute monophasic rat experimental autoimmune encephalomyelitis (EAE). The aim of this study was to evaluate a potential role of GSK-3β in central nervous system (CNS) autoimmunity through its inhibition by lithium. Lithium treatment significantly delayed the onset of EAE paralysis and ameliorated its severity. Lithium treatment reduced the serum level of pro-inflammatory tumor necrosis factor a but not that of interleukin 10. Western blot analysis showed that the phosphorylation of GSK-3β (p-GSK-3β) and its upstream factor Akt was significantly increased in the lithium-treated group. Immunohistochemical examination revealed that lithium treatment also suppressed the activation of ionized calcium binding protein-1-positive microglial cells and vascular cell adhesion molecule-1 expression in the spinal cords of lithium-treated EAE rats. These results demonstrate that lithium ameliorates clinical symptom of acute monophasic rat EAE, and GSK-3 is a target for the suppression of acute neuroinflammation as far as rat model of human CNS disease is involved.

Citrus hallabong [(Citrus unshiu × C. sinensis) × C. reticulata)] exerts potent anti-inflammatory properties in murine splenocytes and TPA-induced murine ear oedema model

Abstract Context: Hallabong [(Citrus unshiu × C. sinensis) X C. reticulata)] (Rutaceae) is a hybrid citrus cultivated in temperate regions of South Korea. Its fruit is well-known for pharmacological properties. Objective: This study examined the anti-inflammatory effect of 80% ethanol extract of Hallabong (HE) on concanavalin A (Con A)-stimulated splenocytes and mouse oedema model induced by 12-O-tetradecanoylphorbal acetate (TPA). Materials and methods: Murine splenocytes treated with HE were stimulated with Con A (10 μg/mL, for 24 h) were evaluated for T-cell population and production of inflammatory cytokines IL-2, IL-4 and IFN-γ. Anti-inflammatory effect of topically applied HE (100 μg/20 μL) on TPA (4 μg/20 μL/ear)-induced ear oedema was investigated in mouse model. Results: HE-treated Con A-stimulated murine splenocytes showed a marked decrease in CD44/CD62L+ memory T-cell population, an important marker for anti-inflammatory activity, and a significant inhibition in the production of IL-2 and IFN-γ. HE treatment had reduced the mouse skin oedema (47%) and myeloperoxidase (MPO) activity significantly (40%) in TPA-challenged tissues. More importantly, immunohistochemical localization revealed the suppressed (p < 0.05) expression of inducible nitric oxide (iNOS), cyclooxygenase-2 (COX2). HE decreased the infiltration of CD3+ T cells and F4/80+ macrophages to the site of inflammation and a topical application of HE significantly suppressed the expression of TNF-α (20.2%). Discussion and conclusion: A topical application of HE can exert a potential anti-inflammatory effect and HE can be explored further as a putative alternative therapeutic agent for inflammatory oedema.

Immunostimulatory effect of pepsin enzymatic extract from Porphyra yezoensis on murine splenocytes: Immunostimulatory effect of PPEE on macrophage

BACKGROUND Porphyra yezoensis is a red alga consumed mainly in Korea, Japan, and China for food. This study researches the immunological effect of pepsin extract of P. yezoensis (PPEE) on murine splenocytes. RESULTS PPEE was not toxic on murine splenocytes and dramatically increased the proliferation of splenocytes compared with untreated control. Flow cytometry assay performed to sum up the effect of PPEE (31.3 and 62.5 µg mL-1 ) on major immune cells revealed that PPEE had no effect on the function of CD3e+ CD4+ T-helper cells, CD3e+ CD8+ T-cytotoxic cells, or CD44+ CD62L- effector T cells in splenocytes compared with untreated control. More importantly, CD45+ CD11b+ macrophage and dendritic cell populations and Ly-6C+ Ly-6G+ macrophages/monocytes in splenocytes were activated by PPEE treatment compared with untreated control. Further experiments showed that PPEE treatment increased the secretion of macrophage-derived cytokines such as interleukin-1β, tumor necrosis factor-α, and interleukin-12, and macrophage-activating cytokines interferon-γ and interleukin-10 compared with untreated control. CONCLUSION Taken together, these results suggest that PPEE has an immune stimulatory effect on macrophages, dendritic cells, and memory T cells. This property signifies the potential medicinal value of PPEE in clinical implications for immune-compromised diseases.