Astaxanthin Protects against Hyperglycemia-Induced Oxidative and Inflammatory Damage to Bone Marrow and to Bone Marrow-Retained Stem Cells and Restores Normal Hematopoiesis in Streptozotocin-Induced Diabetic Mice.

Hyperglycemia has various adverse health effects, some of which are due to chronic oxidative and inflammatory impairment of bone marrow (BM), hematopoietic stem cells (HSCs), and mesenchymal stem cells (MSCs). Astaxanthin (ASTX) has been shown to ameliorate hyperglycemia-associated systemic complications and acute mortality, and this effect is partially associated with restoration of normal hematopoiesis. Here, the effects of ASTX on diabetes-induced complications in BM and BM stem cells were investigated, and the underlying molecular mechanisms were elucidated. Ten-week-old C57BL/6 mice received a single intraperitoneal injection of streptozotocin (STZ; 150 mg/kg) in combination with oral gavage of ASTX (12.5 mg/kg) for 30 or 60 consecutive days. Supplemental ASTX ameliorated acute mortality and restored the STZ-impaired bone mass accrual and BM microenvironment in STZ-injected mice. Oral gavage of ASTX suppressed osteoclast formation in the BM of STZ-injected mice. Specifically, supplementation with ASTX inhibited oxidative stress and senescence induction of BM HSCs and MSCs and ameliorated hematopoietic disorders in STZ-injected mice. These effects of ASTX were associated with BM restoration of angiopoietin 1, stromal cell-derived factor 1, ß-catenin, and Nrf2. Long-term ASTX gavage also recovered the STZ-induced dysfunction in migration, colony formation, and mineralization of BM-derived stromal cells. Further, a direct addition of ASTX exhibited direct and dose-dependent inhibition of osteoclastic activation without cytotoxic effects. Collectively, these results indicate that ASTX protects against diabetes-induced damage in the BM microenvironment in BM, HSCs, and MSCs and restores normal hematopoiesis and bone accrual in STZ-injected mice.

Functional improvement of collagen-based bioscaffold to enhance periodontal-defect healing via combination with dietary antioxidant and COMP-angiopoietin 1.

Scaffolds combined with bioactive agents can enhance bone regeneration at therapeutic sites. We explore whether combined supplementation with coumaric acid and recombinant human-cartilage oligomeric matrix protein-angiopoietin 1 (rhCOMP-Ang1) is an ideal approach for bone tissue engineering. We developed coumaric acid-conjugated absorbable collagen scaffold (CA-ACS) and investigated whether implanting CA-ACS in combination with rhCOMP-Ang1 facilitates ACS- or CA-ACS-mediated bone formation using a rat model of critically sized mandible defects. We examined the mechanisms by which coumaric acid and rhCOMP-Ang1 regulate behaviors of human periodontal ligament fibroblasts (hPLFs). The CA-ACS exhibits greater anti-degradation and mechanical strength properties than does ACS alone. Implanting CA-ACS loaded with rhCOMP-Ang1 greatly enhances bone regeneration at the defect via the activation of angiogenic, osteogenic, and anti-osteoclastic responses compared with other rat groups implanted with an ACS alone or CA-ACS. Treatment with both rhCOMP-Ang1 and coumaric acid increases proliferation, mineralization, and migration of cultured hPLFs via activation of the Ang1/Tie2 signaling axis at a greater rate than treatment with either of them alone. Collectively, this study demonstrates that CA-ACS impregnated with rhCOMP-Ang1 enhances bone regeneration at therapeutic sites, and this enhancement is associated with a synergistic interaction between rhCOMP-Ang1-mediated angiogenesis and coumaric acid-related antioxidant responses.

Astaxanthin Inhibits Diabetes-Triggered Periodontal Destruction, Ameliorates Oxidative Complications in STZ-Injected Mice, and Recovers Nrf2-Dependent Antioxidant System.

Numerous studies highlight that astaxanthin (ASTX) ameliorates hyperglycemic condition and hyperglycemia-associated chronic complications. While periodontitis and periodontic tissue degradation are also triggered under chronic hyperglycemia, the roles of ASTX on diabetes-associated periodontal destruction and the related mechanisms therein are not yet fully understood. Here, we explored the impacts of supplemental ASTX on periodontal destruction and systemic complications in type I diabetic mice. To induce diabetes, C57BL/6 mice received a single intraperitoneal injection of streptozotocin (STZ; 150 mg/kg), and the hyperglycemic mice were orally administered with ASTX (12.5 mg/kg) (STZ+ASTX group) or vehicle only (STZ group) daily for 60 days. Supplemental ASTX did not improve hyperglycemic condition, but ameliorated excessive water and feed consumptions and lethality in STZ-induced diabetic mice. Compared with the non-diabetic and STZ+ASTX groups, the STZ group exhibited severe periodontal destruction. Oral gavage with ASTX inhibited osteoclastic formation and the expression of receptor activator of nuclear factor (NF)-κB ligand, 8-OHdG, γ-H2AX, cyclooxygenase 2, and interleukin-1ß in the periodontium of STZ-injected mice. Supplemental ASTX not only increased the levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and osteogenic transcription factors in the periodontium, but also recovered circulating lymphocytes and endogenous antioxidant enzyme activity in the blood of STZ-injected mice. Furthermore, the addition of ASTX blocked advanced glycation end products-induced oxidative stress and growth inhibition in human-derived periodontal ligament cells by upregulating the Nrf2 pathway. Together, our results suggest that ASTX does not directly improve hyperglycemia, but ameliorates hyperglycemia-triggered periodontal destruction and oxidative systemic complications in type I diabetes.

Oral supplementation with p-coumaric acid protects mice against diabetes-associated spontaneous destruction of periodontal tissue.

OBJECTIVE: Dietary bioactive materials having anti-inflammatory and antioxidant potentials are able to inhibit diabetes-associated periodontal complications. Although numerous studies indicate that administration of p-coumaric acid (p-CA) ameliorates diabetes and diabetes-related complications, the roles of p-CA on periodontal tissue destruction in diabetic mice and the possible mechanisms therein are not completely understood. In this study, we evaluated whether supplementation with p-CA protects mice against diabetes-associated spontaneous periodontal destruction and also explored the associated mechanism therein using in vivo and in vitro experimental systems. MATERIALS AND METHODS: C57BL/6 male mice were divided into sham, streptozotocin (STZ), and STZ+CA groups (n = 5/group). Sham group was intraperitoneally injected with sodium buffer, whereas other two groups were injected with the buffer containing 160 mg/kg of STZ. STZ-induced diabetic mice received oral gavage with p-CA (50 mg/kg) (STZ+CA group) or with buffer only (STZ group) daily for 6 weeks. The effect of p-CA on diabetes-associated spontaneous periodontal destruction was evaluated using µCT analysis, hematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, and immunohistochemical staining methods. The efficacies of p-CA on cell proliferation, osteoblast differentiation, reactive oxygen species (ROS) accumulation, and antioxidant-related marker expression were examined using human periodontal ligament fibroblasts (hPLFs) cultured under high glucose condition. RESULTS: Streptozotocin group exhibited periodontal tissue destruction along with increased inflammation, oxidative stress, and osteoclast formation, as well as with decreased osteogenesis. However, oral administration with p-CA protected mice against STZ-induced periodontal destruction by inhibiting inflammation and osteoclastic activation. STZ+CA group also showed higher expression of antioxidant and osteogenic markers in periodontal tissue than did STZ group. Treatment with high glucose concentration (30 mmol/L) impaired proliferation and osteoblast differentiation of hPLFs along with cellular ROS accumulation, whereas these impairments were almost completely disappeared by supplementation with p-CA. CONCLUSION: These findings demonstrate that supplementation with p-CA inhibits diabetes-associated spontaneous destruction of periodontal tissue by enhancing anti-inflammatory, anti-osteoclastogenic, and antioxidant defense systems in STZ-treated mice.

Glycoproteins and Polysaccharides are the Main Class of Active Constituents Required for Lymphocyte Stimulation and Antigen-Specific Immune Response Induction by Traditional Medicinal Herbal Plants.

Traditional herbal remedies stimulate and modulate the immune system, and it is thought that their glycoproteins and polysaccharides are responsible for this activity. We prepared crude water, protein, and polysaccharide extracts from Atractylodes macrocephala Koidz, Helianthus annuus L., Scutellaria barbata D. Don, and Hedyotis diffusa Willd, respectively, and compared their immune-stimulating activities in vitro and in vivo. All protein and polysaccharide samples of the plants led to greater lymphocyte proliferation and TNF-α and IL-6 production in cultured splenocytes than did the crude water extracts at the same concentrations tested. In addition, the protein and polysaccharide samples did not contain lectin- or lipopolysaccharide-like molecules, so glycoproteins were deduced to be responsible for the lymphocyte stimulation. Oral administration with each of the samples enhanced the hen egg-white lysozyme (HEL)-specific humoral immune and lymphocyte proliferative responses in HEL low-responder C57BL/6 mice. Splenocytes from the mice fed the samples showed significantly greater increases in the level of IFN-γ, but not IL-4, after stimulation with HEL compared with that from the untreated control. However, higher increases in HEL-specific IgG1, IgG2b, and IgG3 rather than IgG2a were found in the mice fed the samples. These results indicate that the sample-mediated enhancement of anti-HEL-specific humoral immune responses was due to the stimulation of B lymphocytes rather than a selective priming of helper T cell populations. Collectively, we suggest that glycoproteins and/or polysaccharides of traditional herbal remedies enhance cellular and humoral immune response induction and thus could be useful for patients who need enhanced immune function.

Intestinal anti-inflammatory activity of the seeds of Raphanus sativus L. in experimental ulcerative colitis models.

ETHNOPHARMACOLOGICAL RELEVANCE: Water extract of Raphanus sativus L. (RSL) seeds was traditionally used to treat digestive inflammatory complaints in Korean culture. RSL seeds exerted antioxidant, anti-inflammatory, and anti-septic functions, suggesting their pharmacological potential for the treatment of inflammatory pathologies associated with oxidative stress such as inflammatory bowel disease. AIM OF THIS STUDY: We evaluated the intestinal anti-inflammatory effects of RSL seed water extract (RWE) in experimental rat models of trinitrobenzenesulphonic acid (TNBS)- or dextran sodium sulfate (DSS)-induced colitis. MATERIALS AND METHODS: RWE was characterized by determining the content of sinapic acid as a reference material and then assayed in the DSS and TNBS models of rat colitis. Male Sprague-Dawley rats were divided into 10 groups (n=7/group): non-colitic control, DSS or TNBS control, DSS colitis groups treated with RWE (100mg/kg) or mesalazine (25mg/kg), and TNBS colitis groups treated with various doses (10, 40, 70, and 100mg/kg) of RWE or mesalazine (25mg/kg). RWE or mesalazine treatment started the same day of colitis induction and rats were sacrificed 24h after the last treatment followed by histological and biochemical analyses. RESULTS: Oral administration with RWE suppressed intestinal inflammatory damages in both DSS- and TNBS-induced colitic rats. The treatment with 100mg/kg RWE recovered intestinal damages caused by TNBS or DSS to levels similar to that of mesalazine, decreasing the activity of myeloperoxidase activity and the secretion of tumor necrosis factor (TNF)-α and interleukin (IL)-1ß. RWE treatment inhibited malondialdehyde production and glutathione reduction in colon of colitis rats. The administration of RWE at dose of 100mg/kg also suppressed the TNBS- or DSS-stimulated expression of TNF-α, IL-1ß, monocyte chemotactic protein-1, inducible nitric oxide, and intercellular adhesion molecule-1. Furthermore, RWE inhibited p38 kinase and DNA-nuclear factor-κB binding activities, both of which were stimulated in the colitic rats. CONCLUSIONS: The current findings show that RWE ameliorates intestinal oxidative and inflammatory damages in DSS and TNBS models of rat colitis, suggesting its beneficial use for the treatment of intestinal inflammatory disorders.

Raphanus sativus L. seeds prevent LPS-stimulated inflammatory response through negative regulation of the p38 MAPK-NF-κB pathway.

The seeds of Raphanus sativus L. (RSL) have long been used as anti-inflammatory traditional medicine. However, scientific bases for the purported potential of the medicine and the associated mechanisms were barely defined. This study investigated the effects of RSL seeds on lipopolysaccharide (LPS)-stimulated inflammatory responses in vitro and in vivo. Treatment with 100 µg/ml ethyl acetate fraction (REF), which was isolated from water extract of the seeds, significantly inhibited LPS-stimulated production of nitric oxide (P < 0.05), interleukin-6 (P < 0.001), and tumor necrosis factor (TNF)-α (P < 0.001) in RAW264.7 cells. Oral supplementation with 30 mg/kg REF protected mice by 90% against LPS-induced septic death and prevented the increases of serum TNF-α and interferon-γ levels in LPS-injected mice. When REF was divided into four sub-fractions (REF-F1-F4), REF-F3 showed the greatest activity to suppress LPS-stimulated production of inflammatory mediators. We subsequently isolated an active fraction from the REF-F3 and identified sinapic acid as the main constituent. The addition of 50 µg/ml active fraction markedly inhibited LPS-stimulated production of inflammatory mediators by suppressing p38 MAPK and nuclear factor-κB activation. Furthermore, supplementation with the active fraction (10 mg/kg) improved the survival rate of LPS-injected mice by 80% of the untreated control. Additional experiments revealed that sinapic acid was the active component responsible for the anti-inflammatory potential of RSL seeds. Collectively, our current results suggest that both RSL seeds and sinapic acid may be attractive materials for treating inflammatory disorders caused by endotoxins.

A phenolic acid phenethyl urea derivative protects against irradiation-induced osteoblast damage by modulating intracellular redox state.

Because irradiation may cause osteoradionecrosis, antioxidant supplementation is often used to suppress irradiation-mediated injury. This study examined whether a synthetic phenethyl urea compound, (E)-1-(3,4-dihydroxyphenethyl)-3-(3,4-dihydroxystyryl)urea (DPDS-U), prevents irradiation-mediated cellular damage in MC3T3-E1 osteoblastic cells. A relatively high dose of irradiation (>4 Gy) decreased cell viability and proliferation and induced DNA damage and cell cycle arrest at the G(2)/M phase with the attendant increase of cyclin B1. Irradiation with 8 Gy induced intracellular reactive oxygen species (ROS) production and lipid peroxidation, and reduced glutathione content and superoxide dismutase activity in the cells. These events were significantly suppressed by treatment with 200 µM DPDS-U or 5 mM N-acetyl cysteine (NAC). DPDS-U or irradiation alone significantly increased heme oxygenase-1 (HO-1) expression and nuclear factor E2 p45-related factor-2 (Nrf2) nuclear translocation. Interestingly, pretreatment with DPDS-U facilitated irradiation-induced activation of the Nrf2/HO-1 pathway. The potential of DPDS-U to mediate HO-1 induction and protect against irradiation-mediated cellular damage was almost completely attenuated by transient transfection with Nrf2-specific siRNA or treatment with a pharmacological HO-1 inhibitor, zinc protoporphyrin IX. Additional experiments revealed that DPDS-U induced a radioprotective mechanism that differs from that induced by NAC through activation of Nrf2/HO-1 signaling. Collectively, our data suggest that DPDS-U-induced radioprotection is due to its dual function as an antioxidant to remove directly excessive intracellular ROS and as a prooxidant to stimulate intracellular redox-sensitive survival signal.

Periodontal fibroblasts modulate proliferation and osteogenic differentiation of embryonic stem cells through production of fibroblast growth factors.

BACKGROUND: Periodontal ligament fibroblasts (PLFs) maintain homeostasis of periodontal ligaments by producing paracrine factors that affect various functions of stem-like cells. It is hypothesized that PLFs induce proliferation and differentiation of stem cells more effectively than gingival fibroblasts (GFs) and skin fibroblasts (SFs). METHODS: PLFs and GFs were isolated from extracted teeth and cultured in the presence and absence of osteogenesis-inducing factors. Mouse embryonic stem (mES) cells and SFs were purchased commercially. mES cells were incubated with culture supernatants of these fibroblasts or cocultured directly with the cells. Proliferation and mineralization in mES cells were determined at various times of incubation. Immunostaining and polymerase chain reaction were performed. The activity of mitogen-activated protein kinase and alkaline phosphatase (ALP) was also measured. RESULTS: In cocultures, PLFs stimulated proliferation of mES cells more effectively than GFs or SFs. Similarly, the addition of culture supernatant of PLFs induced the most prominent proliferation of mES cells, and this was significantly inhibited by treatment with antibody against fibroblast growth factor (FGF)4 or the c-Jun N-terminal kinase inhibitor SP600125 (anthra[1,9-cd]pyrazol-6(2H)-one). Supplementation with culture supernatant from the fibroblasts induced osteogenic differentiation of mES cells in the order PLFs > GFs > SFs. These activities of PLFs were related to their potential to produce osteogenic markers, such as ALP and runt-related transcription factor-2 (Runx2), and to secrete FGF7. Pretreatment of mES cells with the extracellular signal-regulated kinase inhibitor PD98059 [2-(2-amino-3-methyoxyphenyl)-4H-1-benzopyran-4-one] or SP600125 clearly attenuated mineralization induced by culture supernatant of PLF with attendant decreases in mRNA levels of Runx2, bone sialoprotein, osteocalcin, and osteopontin. CONCLUSION: PLFs regulate the proliferation and osteogenic differentiation of mES cells more strongly than GFs and SFs via the secretion of FGF through a mechanism that involves mitogen-activated protein kinase-mediated signaling.

Acteoside suppresses RANKL-mediated osteoclastogenesis by inhibiting c-Fos induction and NF-κB pathway and attenuating ROS production.

Numerous studies have reported that inflammatory cytokines are important mediators for osteoclastogenesis, thereby causing excessive bone resorption and osteoporosis. Acteoside, the main active compound of Rehmannia glutinosa, which is used widely in traditional Oriental medicine, has anti-inflammatory and antioxidant potentials. In this study, we found that acteoside markedly inhibited osteoclast differentiation and formation from bone marrow macrophages (BMMs) and RAW264.7 macrophages stimulated by the receptor activator of nuclear factor-kappaB (NF-κB) ligand (RANKL). Acteoside pretreatment also prevented bone resorption by mature osteoclasts in a dose-dependent manner. Acteoside (10 µM) attenuated RANKL-stimulated activation of p38 kinase, extracellular signal-regulated kinases, and c-Jun N-terminal kinase, and also suppressed NF-κB activation by inhibiting phosphorylation of the p65 subunit and the inhibitor κBα. In addition, RANKL-mediated increases in the expression of c-Fos and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) and in the production of tumor necrosis factor-α, interleukin (IL)-1ß, and IL-6 were apparently inhibited by acteoside pretreatment. Further, oral acteoside reduced ovariectomy-induced bone loss and inflammatory cytokine production to control levels. Our data suggest that acteoside inhibits osteoclast differentiation and maturation from osteoclastic precursors by suppressing RANKL-induced activation of mitogen-activated protein kinases and transcription factors such as NF-κB, c-Fos, and NFATc1. Collectively, these results suggest that acteoside may act as an anti-resorptive agent to reduce bone loss by blocking osteoclast activation.

Inhibition of c-Jun N-terminal kinase sensitizes tumor cells to flavonoid-induced apoptosis through down-regulation of JunD.

Reduction of susceptibility to apoptosis signals is a crucial step in carcinogenesis. Therefore, sensitization of tumor cells to apoptosis is a promising therapeutic strategy. c-Jun NH2-terminal kinase (JNK) has been implicated in stress-induced apoptosis. However, many studies also emphasize the role of JNK on cell survival, although its mechanisms are not completely understood. Previously, we found that inhibition of JNK activity promotes flavonoid-mediated apoptosis of human osteosarcoma cells. We thus determined whether inhibition of JNK sensitizes tumor cells to a bioflavonoid-induced apoptosis, and whether this effect of JNK is a general effect. As the results, quercetin and genistein as well as a flavonoid fraction induced apoptosis of tumor cells, which was further accelerated by specific JNK inhibitor, SP600125 or by small interfering RNA specific to JNK1/2. This effect was specific to types of cells because it was further apparent in tumorigenic cell lines. Inhibition of JNK by SP600125 also reduced flavonoid-stimulated nuclear induction of JunD which was known to have protective role in apoptosis, whereas JNK inhibition alone had little effect on apoptosis. The flavonoid-induced apoptosis of tumor cells was significantly enhanced by transfecting them with antisense JunD oligonucleotides. These results suggest that inhibition of JNK facilitates flavonoid-induced apoptosis through down-regulation of JunD, which is further sensitive to tumor cells. Therefore, combination with a specific JNK inhibitor further enhances the anti-cancer and chemopreventive potential of bio-flavonoids.

Caspase-independent death of human osteosarcoma cells by flavonoids is driven by p53-mediated mitochondrial stress and nuclear translocation of AIF and endonuclease G.

Flavonoids have antioxidant and antitumor promoting effects. Rhus verniciflua Stokes (RVS) is a flavonoid-rich herbal medicine that has long been used in Korea as both a food additive and antitumor agent. It was previous reported that a purified flavonoid fraction prepared from RVS, herein named RCMF (the RVS chloroform-methanol fraction), inhibited the proliferation and induced apoptosis in human osteosarcoma (HOS) cells. This study examined the mechanisms involved in the RCMF-mediated apoptosis in HOS cells. RCMF was shown to be capable of inducing apoptosis in HOS cells by inducing p53 in the cells resulting in the decrease in Bcl-2 level, activation of Bax, and cytoplasmic release of cytochrome c, which led to the translocation of apoptosis-inducing factor (AIF) and endonuclease G (EndoG) into the nucleus. However, the RCMF-induced apoptosis was suppressed by transfecting the cells with antisense p53 oligonucleotides but not by treating them with a MAPK or caspase inhibitor. This suppression occurred through the regulation of Bcl-2 members as well as by preventing the nuclear translocation of the mitochondrial apoptogenic factors. Overall, it appears that p53-mediated mitochondrial stress and the nuclear translocation of AIF and EndoG are mainly required for the apoptosis induced by RCMF.

Flavonoids purified from Rhus verniciflua Stokes actively inhibit cell growth and induce apoptosis in human osteosarcoma cells.

Many studies have suggested that dietary flavonoids are anticancer agents that induce the apoptosis of cancer cells. However, the effects of flavonoids on the induction of apoptosis in osteosarcoma cells are unclear. Previously, a flavonoid fraction, consisting mainly of protocatechuic acid, fustin, fisetin, sulfuretin, and butein, herein named RCMF (the RVS chloroform-methanol fraction), was prepared from a crude acetone extract of Rhus verniciflua Stokes (RVS). This study evaluated the effects of RCMF on the proliferation and apoptosis using human osteosarcoma (HOS) cells. The mechanism of growth inhibition of the HOS cells by the flavonoid fraction, RCMF, was also assessed. The results demonstrated that RCMF exhibited sensitive growth inhibition and induced apoptosis in HOS cells. PARP cleavage was closely associated with the RCMF-induced apoptosis of the HOS cells. Furthermore, the activation of caspase 8 and Bax, the inhibition of Bcl-2 expression, and the release of cytochrome c are believed to be involved in the RCMF-mediated apoptosis. Collectively, these findings suggest that RCMF is an agent which may be capable of inducing sensitive growth inhibition and apoptosis in HOS cells.