Extract of Magnoliae Flos inhibits ovariectomy-induced osteoporosis by blocking osteoclastogenesis and reducing osteoclast-mediated bone resorption

The Protective Role of Magnoliae Flos in Preventing Ovotoxicity and Managing Ovarian Function: An In Vitro and In Vivo Study

Magnoliae Flos (MF) is a medicinal herb widely employed in traditional medicine for relieving sinusitis, allergic rhinitis, headaches, and toothaches. Here, we investigated the potential preventive effects of MF extract (MFE) against 4-vinylcyclohexene diepoxide (VCD)-induced ovotoxicity in ovarian cells and a mouse model of premature ovarian insufficiency (POI). The cytoprotective effects of MFE were assessed using CHO-K1 or COV434 cells. In vivo, B6C3F1 female mice were intraperitoneally injected with VCD for two weeks to induce POI, while MFE was orally administered for four weeks, beginning one week before VCD administration. VCD led to a significant decline in the viabilities of CHO-K1 and COV434 cells and triggered excessive reactive oxygen species (ROS) production and apoptosis specifically in CHO-K1 cells. However, pretreatment with MFE effectively prevented VCD-induced cell death and ROS generation, while also activating the Akt signaling pathway. In vivo, MFE increased relative ovary weights, follicle numbers, and serum estradiol and anti-Müllerian hormone levels versus controls under conditions of ovary failure. Collectively, our results demonstrate that MFE has a preventive effect on VCD-induced ovotoxicity through Akt activation. These results suggest that MFE may have the potential to prevent and manage conditions such as POI and diminished ovarian reserve.

Magnolia biondii flower extract attenuates UVB-induced skin damage through high-mobility group box protein B1

OBJECTIVE

Magnolia biondii, a plant containing many magnolian-like compounds in its flowers or buds, exhibits anti-inflammatory and antiallergic effects; however, no study has addressed its effect on alleviating ultraviolet light (UV)-induced skin damage. We thus aimed at studying the effects of M. biondii flower extract (MB) on UVB-induced skin damage and determine the relationship between cell damage and damage-associated molecular patterns (DAMPs).

METHODS

Reconstructed epidermal models and foreskin samples were selected to detect cellular reactions after UVB irradiation and MB treatment. MTT, haematoxylin-eosin and immunofluorescence staining were used to examine total viability, sunburned cells and expression and migration of DAMPs at 16 or 48 h. Prostaglandin E2 (PGE-2) and interleukin 8 (IL-8) levels were measured using enzyme-linked immunosorbent assays. A clinical UVB-damaged test was carried out on human arms subjected to MB pre- or post-treatment. Human skin probes were used to measure erythema, melanin, ITA° and transepidermal water loss (TEWL), while skin photos were captured using the VISIA system.

RESULTS

MB is rich in lignans such as magnolin, pinoresinol dimethyl ether and fargesin, and shows weak UV absorption at 280-320 nm. Coculturing with MB for 16 or 48 h after UVB irradiation improved the tissue viability and structure of Skinovo-Epi, and reduced the expression and migration of high mobility group box protein B1 (HMGB1) as well as the expression of IL-8 and PGE-2. In the excised foreskin treated with MB after UVB irradiation, the generation of 8-hidroxy-2-deoxyguanosine and nuclear transfer of HMGB1 were reduced. When pre-treated with MB for 3 days, UVB-induced skin erythema and ITA° were significantly decreased. When post-treated with MB for 5 days, a decrease in skin erythema, melanin and TEWL values and an increase in skin ITA° were observed.

CONCLUSIONS

Treatment with MB attenuated UVB-induced skin damage, such as erythema, pigmentation and skin barrier function, by improving the tissue viability and structure and reducing sunburned cells and skin inflammation. This effect may be related to DNA damage, which causes the migration of HMGB1 from the nucleus to the outside of the cell to induce skin inflammation.

Magnoliae flos Downregulated Lipopolysaccharide-Induced Inflammatory Responses via NF-κB/ERK-JNK MAPK/STAT3 Pathways

Background. Magnoliae flos is the dried flower bud of Magnolia biondii and related plants. It has been used as a medicinal herb for the treatment of rhinitis, sinusitis, and sinus headaches. Nevertheless, the effects of Magnoliae flos in microbial infection or sepsis remain unclear. In this study, we investigated the anti-inflammatory effects of Magnoliae flos water extract (MF) in lipopolysaccharide- (LPS-) induced septic mice and LPS-stimulated RAW264.7 macrophages. Results. We found that MF reduced the mortality of LPS-challenged mice. Enzyme immunoassays and reverse transcription polymerase chain reaction analysis revealed that MF administration attenuated mRNA expression and protein production of proinflammatory mediators, including cyclooxygenase 2, inducible nitric oxide synthase, tumor necrosis factor-α, and interleukin-6. In parallel to these results in mice, pretreatment with MF suppressed the LPS-induced production of proinflammatory mediators in RAW264.7 macrophages. In addition, we found that MF exerted its suppressive effects by inhibiting the activation of the mitogen-activated protein kinase, nuclear factor-κB, and signal transducer and activator of transcription pathways at the protein level. Conclusion. MF could be a potential therapeutic agent for regulating excessive inflammatory responses in sepsis.

Pentosan polysulfate regulates hepcidin 1-facilitated formation and function of osteoclast derived from canine bone marrow

Hepcidin which is the crucial regulator of iron homeostasis, produced in the liver in response to anemia, hypoxia, or inflammation. Recent studies have suggested that hepcidin and iron metabolism are involved in osteoporosis by inhibiting osteoblast function and promoting osteoclastogenesis. Pentosan polysulfate (PPS) is a heparin analogue and promising novel therapeutic for osteoarthritis (OA). This study was undertaken to determine whether PPS inhibits hepcidin-facilitated osteoclast (OC) differentiation and iron overload. Canine (n = 3) bone marrow mononuclear cells were differentiated to OC by macrophage colony-stimulating factor and receptor-activator of nuclear factor kappaB ligand with the treatment of hepcidin1 (200, 400, 800, 1200 nmol/L) and PPS (1, 5, 10, 20, 40 μg/mL). Differentiation and function of OC were accessed using tartrate-resistant acid phosphate staining and bone resorption assay while monitoring ferroportin1 (FPN1) and iron concentration by immunocytochemistry. Gene expression of OC for cathepsin K (CTK), matrix metallopeptidase-9, nuclear factor of activated-T-cells cytoplasmic 1 and FPN1 was examined. Hepcidin1 showed significant enhancement of OC number at 800 nmol/L (p<0.01). PPS impeded hepcidin-facilitated OC at 1, 5 and 10 μg/mL and reduction of resorption pits at 5 and 10 μg/mL (p< 0.01). All OC specific genes were downregulated with PPS, specifically in significant manner with CTK at higher concentrations. However, heparin induced FPN1 internalization and degradation was inhibited at higher concentrations of PPS while restoring iron-releasing capability of OC. We demonstrate for the first time that PPS is a novel-inhibitor of hepcidin-facilitated OC formation/function which might be beneficial for treatment of OA and osteoporosis.

Engineered synthetic cell penetrating peptide with intracellular anti-inflammatory bioactivity: An in vitro and in vivo study

Various biomaterials have been used for bone and cartilage regeneration, and inflammation associated with biomaterial implantation is also increased. A 15-mer synthetic anti-inflammatory peptide (SAP15) was designed from human β-defensin 3 to penetrate cells and induce intracellular downregulation of inflammation. The downregulation of inflammation was achieved by the binding of SAP15 to intracellular histone deacetylase (HDAC5). SAP15-mediated inhibition of inflammation was examined in vitro and in vivo using murine macrophages, human articular chondrocytes, and a collagen-induced arthritis (CIA) rat model. Surface plasmon resonance and immunoprecipitation assays indicated that SAP15 binds to HDAC5. SAP15 inhibited the lipopolysaccharide (LPS)-induced phosphorylation of intracellular HDAC5 and NF-κB p65 in murine macrophages. SAP15 treatment increased aggrecan and type II collagen expression and decreased osteocalcin expression in LPS-induced chondrocytes. Subcutaneous injection of SAP15-loaded sodium hyaluronic acid (HA) solution significantly decreased hind paw swelling, joint inflammation, and serum cytokine levels in CIA rats compared with the effects of sodium HA solution alone. The SAP15-loaded HA group exhibited preservation of cartilage and bone structure in CIA rat joints. Moreover, a more robust anti-inflammatory effect of the SAP15 loaded HA was observed than that of etanercept (an anti-tumor necrosis factor-alpha [TNF-α] antibody)-loaded HA. These findings suggest that SAP15 has an anti-inflammatory effect that is not controlled by sodium HA and is mediated by inhibiting HDAC5, unlike the anti-inflammatory mechanism of etanercept. These results demonstrate that SAP15 is useful as an inflammatory regulator of biomaterials and can be developed as a therapeutic for the treatment of inflammation.

Development of a comprehensive quality control method for the quantitative analysis of volatiles and lignans in Magnolia biondii Pamp. by near infrared spectroscopy

The quality of drug is vital to its curative effect, thus it is important to develop a comprehensive quality control method for commonly used drugs. In this study, we developed a Gas chromatography-mass spectrometry separation method for the qualitative and quantitative analysis of volatiles, together with a High-performance liquid chromatography-mass spectrometry separation method for lignans in Magnolia biondii Pamp.. 79 volatiles and 11 lignans were identified via comparing their chromatographic behavior and mass spectra data with those in the literature. The methods were then used to determine the contents of volatiles (1, 8-cineole, d-Limonene, α-terpineol, linalool, L-camphor brain and bornyl acetate) and lignans (epieudesmin, magnolin, epi-magnolin A and fargesin) in Magnolia biondii Pamp.. Subsequently, 13 qualitative models including volatiles (1, 8-cineole, d-Limonene, α-terpineol, linalool, L-camphor brain and bornyl acetate), water-soluble extractive, lignans (pinoresinol dimethyl ether, magnolin, epi-magnolin A and fargesin) and moisture were developed by Near-Infrared Spectroscopy based on partial least square regression herein. The reference values were obtained by High-performance liquid chromatography, Gas chromatography and etc., while the predicted values were attained from the NIR spectrum. Compared with the traditional detection methods, NIR technique methodology significantly improved the ability to evaluate the quality of Magnolia biondii Pamp., which had the advantages of convenience, celerity, highly efficiency, low cost, no harm to samples, no reagent consumption, and no pollution to the environment. Moreover, the systematic analysis method combined pharmaceutical analysis with pharmacochemistry was proposed to prepare volatiles, water-soluble extractive and lignans parts from the same sample. This way could extract more index components to be beneficial in the quality control of Magnolia biondii Pamp. roundly.

Lirioresinol B dimethyl ether inhibits NF-κB and COX-2 and activates IκBα expression in CCl4-induced hepatic fibrosis

Background

Inflammation is one of the key components in the initiation and progression of hepatic diseases. If not treated, inflammation may cause cell dysplasia, and ultimately cancer. In the current study, we investigated the anti-inflammatory and anti-cancer activities of plant isolated compound Lirioresinol B Dimethyl Ether (LBDE) extracted from the seeds of Magnolia fargesii CHENG (Magnoliaceae) against HepG2 cells as well as in BALB/C male mice.

Methods

We assessed the antioxidant and anti-proliferative effects of plant compounds using DPPH assay and HepG2 cell lines. Carbon tetrachloride (CCl₄) and Diethylnitrosamine (DEN) were used to induce liver cell dysplasia followed by hepatocellular carcinoma (HCC) in BALB/C male mice for 12 weeks. We investigated the underlying mechanism by using histopathology and immunoblot experiments.

Results

Intraperitoneal injection of LBDE (50 mg/kg body weight/day) inhibited CCl₄-induced HCC. Free radical scavenging assay shows the strong anti-oxidant activity of LBDE. Western blot results show that LBDE down-regulated nuclear factor kappa B (NFκB) and cyclooxygenase (COX-2) by preventing the phosphorylation of I kappa B alpha (IκBα) in CCl₄ treated group. LBDE also improved liver function by decreasing Alkaline Phosphatase (ALP), aspartate aminotransferase (AST) and Alanine Aminotransferase (ALT) levels. Histopathology results revealed that LBDE decreased granulomas and express normal morphology of hepatocytes.

Conclusions

These preliminary results show that LBDE has the potential to inhibit CCl₄-induced liver cell dysplasia and prevents cancer development by regulating NFκB/COX-2 activation.

Water extract of Cnidii Rhizoma suppresses RANKL-induced osteoclastogenesis in RAW 264.7 cell by inhibiting NFATc1/c-Fos signaling and prevents ovariectomized bone loss in SD-rat

Background

Cnidii Rhizoma is the dried root stem of Cnidium officinale Makino. Cnidii Rhizoma (CR) has been used to treat menstrual irregularity, menstrual pain, and menopause in Korea. However, the effects and mechanisms of CR on RANKL-induced osteoclastogenesis pathway remain to be elucidated. In this study, we investigated the effects of CR on the inhibition of bone resorption of osteoclast and its mechanism RANK signaling pathway.

Methods

The anti-osteoclastogenesis of water extract of CR was measured using RAW 264.7 cell. Tartrate-resistant acid phosphatase (TRAP) assay, pit assay, reverse transcription polymerase chain reaction (RT-PCR) and western blot were performed. Moreover, the effects of CR were determined with an in vivo model using ovariectomized (OVX) rats.

Results

CR extract suppressed osteoclastogenesis, its activity and bone resorption activity through decreasing gene of osteoclast-related such as nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), c-Fos, etc. Moreover, CR extract prevented the bone loss in OVX rats.

Conclusion

These results show that CR has a positive effect on menopausal osteoporosis by suppressing osteoclastogenesis.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2611-8) contains supplementary material, which is available to authorized users.

Fermented Oyster Extract Prevents Ovariectomy-Induced Bone Loss and Suppresses Osteoclastogenesis

There is growing interest in bioactive substances from marine organisms for their potential use against diverse human diseases. Osteoporosis is a skeletal disorder associated with bone loss primarily occurring through enhanced osteoclast differentiation and resorption. Recently, we reported the anti-osteoclastogenic activity of fermented Pacific oyster (Crassostrea gigas) extract (FO) in vitro. The present study focused on investigating the anti-osteoporotic efficacy of FO in bone loss prevention in an experimental animal model of osteoporosis and elucidating the mechanism underlying its effects. Oral administration of FO significantly decreased ovariectomy-induced osteoclast formation and prevented bone loss, with reduced serum levels of bone turnover biomarkers including osteocalcin and C-terminal telopeptide fragment of type I collagen C-terminus (CTX). FO significantly suppressed receptor activator of nuclear factor-κB ligand (RANKL)-induced differentiation of bone marrow-derived macrophages (BMMs) into osteoclasts and attenuated the induction of osteoclast-specific genes required for osteoclastogenesis and bone resorption. Furthermore, FO inhibited RANKL-mediated IκBα and p65 phosphorylation in BMMs. Taken together, these results demonstrate that FO effectively suppresses osteoclastogenesis in vivo and in vitro, and that FO can be considered as a potential therapeutic option for the treatment of osteoporosis and osteoclast-mediated skeletal diseases.

Antiperiodontitis Effects of Magnolia biondii Extract on Ligature-Induced Periodontitis in Rats

Over the past decades, periodontitis has become a rising health problem and caused various diseases. In the many studies shows that some extracts and compound to the prevention and treatment of periodontitis. This study focuses on the effects of inhibition of gingival damage and alveolar bone loss. The aim of this study was to evaluate the protective effects of Magnolia biondii extract (MBE) against ligature-induced periodontitis in rats. A ligature was placed around the molar teeth for 8 weeks, and MBE was administered for 8 weeks. Gingival tissue damage and alveolar bone loss were measured by microcomputed tomography (CT) analysis and histopathological examination. Serum Interluekin-1 β (IL-1β), tumor necrosis factor-α (TNF-α), cyclooxygenases-2 (COX-2), and receptor activator of nuclear factor-κB ligand (RANKL) levels were investigated using commercial kits to confirm the antiperiodontitis effects of MBE. We confirmed that ligature-induced periodontitis resulted in gingival tissue damage and alveolar bone loss. However, treatment for 8 weeks with MBE protected from periodontal tissue damage and downregulated serum inflammatory cytokine factors and RANKL levels. These results suggest that MBE exerts antiperiodontitis effects by inhibiting gingival tissue destruction and alveolar bone loss through regulation of anti-inflammatory cytokines in periodontitis-induced rats.

Inhibitory effects of sodium pentosan polysulfate on formation and function of osteoclasts derived from canine bone marrow

BACKGROUND

Sodium pentosan polysulfate (NaPPS) was testified as a chondroprotective drug in with a detailed rationale of the disease-modifying activity. This study was undertaken to determine whether anti-osteoarthritis drug, NaPPS inhibited osteoclasts (OC) differentiation and function. Canine bone marrow mononuclear cells (n = 6) were differentiated to OC by maintaining with receptor activator of nuclear factor kappa B ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) for up to 7 days with the treatment of NaPPS at concentration of 0, 0.2, 1 and 5 μg/mL. Differentiation and function of OC were accessed using tartrate-resistant acid phosphate (TRAP) staining and bone resorption assay, while monitoring actin ring formation. Invasion and colocalization patterns of fluorescence-labeled NaPPS with transcribed gene in OC were monitored. Gene expression of OC for cathepsin K (CTK), matrix metallopeptidase-9 (MMP-9), nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), c-Fos, activator protein-1(AP-1) and carbonic anhydrase II was examined using real-time PCR.

RESULTS

Significant inhibition of OC differentiation was evident at NaPPS concentration of 1 and 5 μg/mL (p < 0.05). In the presence of 0.2 to 5 μg/mL NaPPS, bone resorption was attenuated (p < 0.05), while 1 and 5 μg/mL NaPPS achieved significant reduction of actin ring formation. Intriguingly, fluorescence-labeled NaPPS invaded in to cytoplasm and nucleus while colocalizing with actively transcribed gene. Gene expression of CTK, MMP-9 and NFATc1 were significantly inhibited at 1 and 5 μg/mL (p < 0.05) of NaPPS whereas inhibition of c-Fos and AP-1 was identified only at concentration of 5 μg/mL (p < 0.05).

CONCLUSIONS

Taken together, all the results suggest that NaPPS is a novel inhibitor of RANKL and M-CSF-induced CTK, MMP-9, NFATc1, c-Fos, AP-1 upregulation, OC differentiation and bone resorption which might be a beneficial for treatment of inflammatory joint diseases and other bone diseases associated with excessive bone resorption.

Age-dependent variations of cancellous bone in response to ovariectomy in C57BL/6J mice

The ovariectomized (OVX) mouse model has been widely accepted to be suitable for the study of postmenopausal osteoporosis. However, whether C57BL/6J mice, a commonly used genetic background mouse strain, is an appropriate model for postmenopausal osteoporosis remains controversial. The present study investigated the effect of the OVX model on alterations in bone density and microarchitecture in C57BL/6J female mice of different ages. C57BL/6J mice were divided into 8-, 12- and 16-week-old groups (OVX₈, OVX₁₂ and OVX₁₆) from the beginning of OVX. At 8 weeks post-surgery, the mice were anesthetized and micro-computed tomography was used to analyze the bone density and microarchitecture. The results revealed that OVX-induced loss of cancellous bone was greatest in OVX₈, moderate in OVX₁₂, and only a weak bone loss was observed in the OVX₁₆ group when compared with the SHAM₁₆ control group. In addition, the effect of genetic backgrounds in response to the OVX model were examined. Several other strains of mice, including inbred (BALB/c) and outbred (ICR and Kunming), were used in the present study, all of which were subjected to OVX at 8 weeks of age. The present findings revealed that the highest rate of bone loss was detected in C57BL/6J female mice. In addition, treatment with estrogen (17β-estradiol, 30 µg/kg five times per week) led to a significant increase in bone density in C57BL/6J mice compared with the other strains of mice. Therefore, these results may provide novel insights into the age- and strain-associated effect of OVX on regulating turnover of bone in female mice. The present findings also suggest 8-week-old C57BL/6J mice as an animal model for postmenopausal osteoporosis and preclinical testing of potential therapies for this disease.

Polygonatum sibiricum polysaccharide inhibits osteoporosis by promoting osteoblast formation and blocking osteoclastogenesis through Wnt/β-catenin signalling pathway

Bone homeostasis is maintained by a balance between bone formation by osteoblasts and bone resorption by osteoclasts. Osteoporosis occurs when osteoclast activity surpasses osteoblast activity. Our previous studies showed the plant-derived natural polysaccharide (Polygonatum sibiricum polysaccharide or PSP) had significant anti-ovariectomy (OVX)-induced osteoporosis effects in vivo, but the mechanisms of PSP’s anti-osteoporosis effect remains unclear. In this study, we assessed PSP’s effect on the generation of osteoblast and osteoclast in vitro. This study showed that PSP promoted the osteogenic differentiation of mouse bone marrow stromal cells (BMSCs) without affecting BMPs signaling pathway. This effect was due to the increased nuclear accumulation of β-catenin, resulting in a higher expression of osteoblast-related genes. Furthermore, the study showed PSP could inhibit the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis and exert prophylatic protection against LPS-induced osteolysis in vivo. This effect was also related to the increased nuclear accumulation of β-catenin, resulting in the decreased expression of osteoclast-related genes. In conclusion, our results showed that PSP effectively promoted the osteogenic differentiation of mouse BMSCs and suppressed osteoclastogenesis; therefore, it could be used to treat osteoporosis.

Ostericum koreanum Reduces LPS-Induced Bone Loss Through Inhibition of Osteoclastogenesis

The roots of Ostericum koreanum (OK) Maximowicz have traditionally been used to produce an herbal medicine reported to possess anti-inflammatory, anti-oxidant, antimicrobial, and antitumor activities; however, its effect on bone metabolism has not yet been reported. The present study examined the effects of OK extract on lipopolysaccharide (LPS)-induced bone loss in mice by investigating bone structure and the levels of the receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) in serum and bone marrow fluid (BMF). The effects of OK extract on osteoclastogenesis were also investigated in mouse bone marrow macrophages by examining the formation of tartrate-resistant acid phosphatase (TRAP)-positive cells, the actin ring, and bone resorption activity. OK reduced LPS-induced bone destruction in vivo via a decrease in the RANKL/OPG ratio. Furthermore, it suppressed the formation of TRAP-positive cells and the actin ring, and reduced the bone-resorbing activity of mature osteoclasts. OK also significantly down-regulated the expression of various osteoclast-specific genes. However, it did not affect osteoblast differentiation, or the expression of genes involved in this process. These results demonstrated that OK prevented LPS-induced bone loss by decreasing the RANKL/OPG ratio in serum and BMF, and inhibited osteoclast differentiation and function, suggesting that OK represents a potential therapeutic drug for the treatment of osteoclast-associated bone diseases.

The effects of Lycii Radicis Cortex on RANKL-induced osteoclast differentiation and activation in RAW 264.7 cells

Post-menopausal osteoporosis is a serious age-related disease. After the menopause, estrogen deficiency is common, and excessive osteoclast activity causes osteoporosis. Osteoclasts are multinucleated cells generated from the differentiation of monocyte/macrophage precursor cells such as RAW 264.7 cells. The water extract of Lycii Radicis Cortex (LRC) is made from the dried root bark of Lycium chinense Mill. and is termed 'Jigolpi' in Korea. Its effects on osteoclastogenesis and post‑menopausal osteoporosis had not previously been tested. In the present study, the effect of LRC on receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced osteoclast differentiation was demonstrated using a tartrate-resistant acid phosphatase (TRAP) assay and pit formation assay. Moreover, in order to analyze molecular mechanisms, we studied osteoclastogenesis-related markers such as nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), c-Fos, receptor activator of NF-κB (RANK), TRAP, cathepsin K (CTK), matrix metallopeptidase-9 (MMP-9), calcitonin receptor (CTR) and carbonic anhydrase Ⅱ (CAII) using RT-qPCR and western blot analysis. Additionally, we also determined the effect of LRC on an ovariectomized (OVX) rat model. We noted that LRC inhibited RANKL-induced osteoclast differentiation via suppressing osteoclastogenesis-related markers. It also inhibited osteoporosis in the OVX rat model by decreasing loss of bone density and trabecular area. These results suggest that LRC exerts a positive effect on menopausal osteoporosis.

Aschantin targeting on the kinase domain of mammalian target of rapamycin suppresses epidermal growth factor-induced neoplastic cell transformation

Mammalian target of rapamycin (mTOR), a serine/threonine protein kinase, forms two different complexes, complex 1 and 2, and plays a key role in the regulation of Akt signaling-mediated cell proliferation and transformation. This study reveals aschantin, a natural compound abundantly found in Magnolia flos, as a novel mTOR kinase inhibitor. Aschantin directly targeted the active pocket of mTOR kinase domain by competing with adenosine triphosphate (ATP), but not PI3K and PDK1. Aschantin inhibited epidermal growth factor (EGF)-induced full activation of Akt by phosphorylation at Ser473/Thr308, resulting in inhibition of the mTORC2/Akt and Akt/mTORC1/p70S6K signaling pathways and activation of GSK3β by abrogation of Akt-mediated GSK3β phosphorylation at Ser9. The activated GSK3β inhibited cell proliferation by c-Jun phosphorylation at Ser243, which facilitated destabilization and degradation of c-Jun through the ubiquitination-mediated proteasomal degradation pathway. Notably, aschantin treatment decreased c-Jun stability through inhibition of the mTORC2-Akt signaling pathway, which suppressed EGF-induced anchorage-independent cell transformation in non-malignant JB6 Cl41 and HaCaT cells and colony growth of LNCaP and MIAPaCa-2 cancer cells in soft agar. Altogether, the results show that aschantin targets mTOR kinase and destabilizes c-Jun, which implicate aschantin as a potential chemopreventive or therapeutic agent.

15-deoxy-δ12,14-prostaglandin j2 inhibits osteolytic breast cancer bone metastasis and estrogen deficiency-induced bone loss

Breast cancer is the major cause of cancer death in women worldwide. The most common site of metastasis is bone. Bone metastases obstruct the normal bone remodeling process and aberrantly enhance osteoclast-mediated bone resorption, which results in osteolytic lesions. 15-deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) is an endogenous ligand of peroxisome proliferator-activated receptor gamma (PPARγ) that has anti-inflammatory and antitumor activity at micromolar concentrations through PPARγ-dependent and/or PPARγ-independent pathways. We investigated the inhibitory activity of 15d-PGJ₂ on the bone loss that is associated with breast cancer bone metastasis and estrogen deficiency caused by cancer treatment. 15d-PGJ₂ dose-dependently inhibited viability, migration, invasion, and parathyroid hormone-related protein (PTHrP) production in MDA-MB-231 breast cancer cells. 15d-PGJ₂ suppressed receptor activator of nuclear factor kappa-B ligand (RANKL) mRNA levels and normalized osteoprotegerin (OPG) mRNA levels in hFOB1.19 osteoblastic cells treated with culture medium from MDA-MB-231 cells or PTHrP, which decreased the RANKL/OPG ratio. 15d-PGJ₂ blocked RANKL-induced osteoclastogenesis and inhibited the formation of resorption pits by decreasing the activities of cathepsin K and matrix metalloproteinases, which are secreted by mature osteoclasts. 15d-PGJ₂ exerted its effects on breast cancer and bone cells via PPARγ-independent pathways. In Balb/c nu/nu mice that received an intracardiac injection of MDA-MB-231 cells, subcutaneously injected 15d-PGJ₂ substantially decreased metastatic progression, cancer cell-mediated bone destruction in femora, tibiae, and mandibles, and serum PTHrP levels. 15d-PGJ₂ prevented the destruction of femoral trabecular structures in estrogen-deprived ICR mice as measured by bone morphometric parameters and serum biochemical data. Therefore, 15d-PGJ₂ may be beneficial for the prevention and treatment of breast cancer-associated bone diseases.

Antiosteoporosis Activity of New Oriental Medicine Preparation (Kyungokgo Mixed with Water Extract of Hovenia dulcis) on the Ovariectomized Mice

Protective effect of new oriental medicine (Kyungokgo mixed with water extract of Hovenia dulcis, KOGHD) was assessed on the bone loss induced mice by ovariectomy. In the in vivo experiments, antiosteoporosis effect of KOGHD was investigated using ovariectomized osteoporosis mice model. After 6 weeks of treatment, the mice were euthanized, and the effect of Kyungokgo (KOG) and KOGHD on body weight, spleen weigh, thymus weight, uterine weight, serum biochemical indicators, bone weight and length, immune cell population, bone morphometric parameters, and histological stains was observed. Our results showed that KOGHD prevented the deterioration of trabecular microarchitecture caused by ovariectomy, which were accompanied by the lower levels of bone turnover markers and immune cell population as evidenced by the inhibition of RANKL-mediated osteoclast differentiation without cytotoxic effect on bone marrow derived macrophages (BMMs). Therefore, these results suggest that the Hovenia dulcis (HD) supplementation in the KOG may also prevent and treat bone loss.

Effects of Brown Rice Extract Treated with Lactobacillus sakei Wikim001 on Osteoblast Differentiation and Osteoclast Formation

Phytic acid (myo-inositol hexakisphosphate) or phytate is considered an anti-nutrient due to the formation of precipitated complexes that strongly reduces the absorption of essential dietary minerals. In this study, brown rice with reduced phytate was made by inoculation with Lactobacillus sakei Wikim001 having high phytase activity. The effects of brown rice extract treated with L. sakei Wikim001 (BR-WK) on osteoblast differentiation and osteoclast formation were investigated. The proliferation of SaOS-2 cells was measured by the MTT assay. Treatment with BR-WK increased cell proliferation by 136% at a concentration of 100 μg/mL. The Alkaline phosphate activity in SaOS-2 cells was 129% higher when BR-WK was processed at a concentration of 100 μg/mL. The proliferation of bone marrow macrophages decreased by nearly 60% in response to treatment with BR-WK. In addition, BR-WK reduced the number of tartrate-resistant acid phosphatase-positive (TRAP⁺) multinucleated cells from bone marrow macrophages. These results indicate that BR-WK stimulates bone formation through its positive action on osteoblast differentiation and function and furthermore, decreases osteoclast differentiation.

Medicinal herbs in the prevention and treatment of osteoporosis

Osteoporosis is a common disease with wide prevalence, especially in the elderly population. Osteoporosis induced fractures not only decrease the patient's life quality, but also cause heavy financial burden to the society. Although current medications for osteoporosis are effective, numerous adverse effects have been observed accompanying their clinical applications. Effective prevention and therapy strategies with high safety are critical, which benefit both individual patients and the whole society. Traditional Chinese medicines have been used for thousands of years to treat bone related diseases in China and a number of modern preparations have been developed that are currently commercially available. In addition, several medicinal herbs demonstrated therapeutic effects against osteoporosis in animal models. This paper reviewed the anti-osteoporotic effects of traditional Chinese formulas, medicinal herbs and bioactive constituents based on clinical trials and in vivo animal studies. Due to the lack of rigorous studies to compare the effectiveness with conventional interventions, traditional formulas are recommended as alternative medications or supplements to treat osteoporosis at the current stage. Although there are abundant natural resources with anti-osteoporotic effects, either in the form of medicinal herbs or bioactive components, much work need to be accomplished before they are developed into potential drugs.

Ameliorative effects of Schizandra chinensis on osteoporosis via activation of estrogen receptor (ER)-α/-β

Estrogen deficiency in menopausal women is the main cause of osteoporosis. Phytoestrogen could be a suitable candidate for treatment of post-menopausal osteoporosis. Recent studies showed that S. chinensis contains several lignans, which may be phytoestrogen. In this study, we investigated the ameliorative effects of S. chinensis on post-menopausal osteoporosis. 30% ethanol extract of S. chinensis (SC) was administered orally for 6 weeks after 7 weeks of ovariectomized-induced osteoporosis. Bone mineral density was significantly increased following increased serum osteocalcin levels by SC treatment. Histological analysis showed that SC reduced the increased growth plate of the epiphyseal plate in femur. In addition, pores within bone marrow cells filling the lateral and medial epicondyle were decreased. Serum estradiol concentration was significantly increased in the SC-treated group. The expressions of estrogen receptor-α and -β were increased in uterus and MCF-7 breast cancer cells by SC treatment. And two transcriptions of proto-oncogenes, c-fos and c-Jun, were suppressed by treatment of SC. From these data, we propose that S. chinensis attenuates post-menopausal osteoporosis with its phytoestrogenic effects. S. chinensis may have the potential to be used as an alternative for treatment of osteoporosis.

Deficiency of adiponectin protects against ovariectomy-induced osteoporosis in mice

Adipokine adiponectin (APN) has been recently reported to play a role in regulating bone mineral density (BMD). To explore the mechanism by which APN affects BMD, we investigated BMD and biomechanical strength properties of the femur and vertebra in sham-operated (Sham) and ovariectomized (OVX) APN knockout (KO) mice as compared to their operated wild-type (WT) littermates. The results show that APN deficiency has no effect on BMD but induces increased ALP activity and osteoclast cell number. While OVX indeed leads to significant bone loss in both femora and vertebras of WT mice with comparable osteogenic activity and a significant increase in osteoclast cell number when compared to that of sham control. However, no differences in BMD, ALP activity and osteoclast cell number were found between Sham and OVX mice deficient for APN. Further studies using bone marrow derived mesenchymal stem cells (MSCs) demonstrate an enhanced osteogenic differentiation and extracellular matrix calcification in APN KO mice. The possible mechanism for APN deletion induced acceleration of osteogenesis could involve increased proliferation of MSCs and higher expression of Runx2 and Osterix genes. These findings indicate that APN deficiency can protect against OVX-induced osteoporosis in mice, suggesting a potential role of APN in regulating the balance of bone formation and bone resorption, especially in the development of post-menopausal osteoporosis.

Tetrahydrofurofuran-type lignans inhibit breast cancer-mediated bone destruction by blocking the vicious cycle between cancer cells, osteoblasts and osteoclasts

Breast cancer frequently spreads to bone. The interaction between bone metastases and microenvironment, referred as the "vicious cycle", increases both tumor burden and bone destruction. Therefore, inhibition at any point in this "vicious cycle" can reduce malignant osteolytic lesions in patients with advanced breast cancer. In this study, we evaluated whether tetrahydrofurofuran-type lignans derived from Magnoliae Flos, commonly used in traditional Asian medicine to treat inflammatory diseases, could block breast cancer-mediated bone loss. Aschatin, fargesin, lirioresinol B dimethyl ether, and magnolin at noncytotoxic concentrations suppressed mRNA expression and secretion of osteolytic factor PTHrP in MDA-MB-231 metastatic human breast cancer cells. Fargesin inhibited TGF-β-stimulated cell viability, migration, and invasion and decreased TGF-β-induced PTHrP production in MDA-MB-231 cells. In addition, these lignans reduced RANKL/OPG ratio in PTHrP-treated hFOB1.19 human osteoblastic cells and inhibited RANKL-mediated osteoclast differentiation in mouse bone marrow macrophages. Aschatin, fargesin, lirioresinol B dimethyl ether, and magnolin substantially reduced bone-resorbing activity of osteoclasts by inhibiting MMP-9 and cathepsin K activities. Furthermore, orally administered fargesin inhibited tumor growth and cancer-mediated bone destruction in mice with MDA-MB-231 cells injected into calvarial tissues. Aschatin, fargesin, lirioresinol B dimethyl ether, and magnolin blocked initiation and progression of the "vicious cycle" between breast cancer metastases and bone microenvironment by inhibiting PTHrP production in breast cancer cells and osteoclastic bone resorption. Therefore, these tetrahydrofurofuran-type lignans have the potential to serve as beneficial agents to prevent and treat cancer-induced bone destruction in breast cancer patients.