Morin attenuates osteoclast formation and function by suppressing the NF-κB, MAPK and calcium signalling pathways.

Morin is a natural compound isolated from moraceae family members and has been reported to possess a range of pharmacological activities. However, the effects of morin on bone-associated disorders and the potential mechanism remain unknown. In this study, we investigated the anti-osteoclastogenic effect of morin in vitro and the potential therapeutic effects on ovariectomy (OVX)-induced osteoporosis in vivo. In vitro, by using a bone marrow macrophage-derived osteoclast culture system, we determined that morin attenuated receptor activator of nuclear factor (NF)-κB ligand (RANKL)-induced osteoclast formation via the inhibition of the mitogen-activated protein kinase (MAPK), NF-κB and calcium pathways. In addition, the subsequent expression of nuclear factor of activated T cells c1 (NFATc1) and c-fos was significantly suppressed by morin. In addition, NFATc1 downregulation led to the reduced expression of osteoclastogenesis-related marker genes, such as V-ATPase-d2 and Integrin ß3. In vivo, results provided that morin could effectively attenuate OVX-induced bone loss in C57BL/6 mice. In conclusion, our results demonstrated that morin suppressed RANKL-induced osteoclastogenesis via the NF-κB, MAPK and calcium pathways, in addition, its function of preventing OVX-induced bone loss in vivo, which suggested that morin may be a potential therapeutic agent for postmenopausal osteoporosis treatment.

Morin improves functional recovery after spinal cord injury in rats by enhancing axon regeneration via the Nrf2/HO-1 pathway.

Spinal cord injury (SCI) is a devastating neurological occurrence that usually leads to a loss of motor and sensory function in patients. Axon regeneration has been reported to be crucial for recovery after trauma to the nervous system. Morin, a natural bioflavonoid obtained from the Moraceae family, has previously been reported to exert neuroprotective effects. In our study, we investigated the protective effects of morin on PC12 cells and primary neurons treated with oxygen-glucose deprivation (OGD) and its function in an SCI model. In vitro experiments showed that treating neuronal cells with morin enhanced axonal regeneration after OGD treatment by regulating microtubule stabilization and protecting mitochondrial function. Mechanistically, morin protected neuronal cells exposed to OGD by activating the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway. An in vivo study illustrated that oral morin administration improved microtubule stability and promoted axon regeneration in SCI rats. Taken together, this study showed that treatment with morin improves functional recovery after SCI and that morin may serve as a potential agent for treating SCI.

Astilbin prevents bone loss in ovariectomized mice through the inhibition of RANKL-induced osteoclastogenesis.

Osteoporosis is the most common osteolytic disease characterized by excessive osteoclast formation and resultant bone loss, which afflicts millions of patients around the world. Astilbin, a traditional herb, is known to have anti-inflammatory, antioxidant and antihepatic properties, but its role in osteoporosis treatment has not yet been confirmed. In our study, astilbin was found to have an inhibitory effect on the RANKL-induced formation and function of OCs in a dose-dependent manner without cytotoxicity. These effects were attributed to its ability to suppress the activity of two transcription factors (NFATc1 and c-Fos) indispensable for osteoclast formation, followed by inhibition of the expression of bone resorption-related genes and proteins (Acp5/TRAcP, CTSK, V-ATPase-d2 and integrin ß3). Furthermore, we examined the underlying mechanisms and found that astilbin repressed osteoclastogenesis by blocking Ca2+ oscillations and the NF-κB and MAPK pathways. In addition, the therapeutic effect of MA on preventing bone loss in vivo was further confirmed in an ovariectomized mouse model. Therefore, considering its ability to inhibit RANKL-mediated osteoclastogenesis and the underlying mechanisms, astilbin might be a potential candidate for treating osteolytic bone diseases.

Schisandrin B attenuates epidural fibrosis in postlaminectomy rats by inhibiting proliferation and extracellular matrix production of fibroblasts.

Laminectomy has been widely considered one of the most common treatments for lumbar disorders. Epidural fibrosis (EF) is a common complication after laminectomy, causing recurrent postoperative pain. Schisandrin B (Sch.B), the active ingredient extracted from Schisandra chinensis Fructus, has been found to have potent antiproliferative and antifibrotic effects on several cells. This study aimed to investigate the effects of Sch.B on the prevention of postlaminectomy EF formation. In vitro, we studied the effects of Sch.B on transforming growth factor beta 1 (TGF-ß1)-induced proliferation and extracellular matrix (ECM) production of primary fibroblasts, as well as its underlying mechanism. We found that Sch.B not only inhibited the proliferation of fibroblasts but also reduced ECM production, including that of connective tissue growth factor, fibronectin, and type I collagen, in a dose-dependent manner. Mechanistically, we found that Sch.B suppressed TGF-ß1-stimulated activation of the Smad2/3 and mitogen-activated protein kinase pathways. Moreover, the in vivo study demonstrated that Sch.B treatment attenuated the progression of EF in a postlaminectomy rat model via reducing the cell number and ECM production of scar tissue. Taken together, these data suggested that Sch.B possesses great potential value as a preventative agent for EF.

Madecassoside inhibits estrogen deficiency-induced osteoporosis by suppressing RANKL-induced osteoclastogenesis.

Osteoporosis is the most common osteolytic disease characterized by excessive osteoclast formation and resultant bone loss, which afflicts millions of patients around the world. Madecassoside (MA), isolated from Centella asiatica, was reported to have anti-inflammatory and antioxidant activities, but its role in osteoporosis treatment has not yet been confirmed. In our study, MA was found to have an inhibitory effect on the RANKL-induced formation and function of OCs in a dose-dependent manner without cytotoxicity. These effects were attributed to its ability to suppress the activity of two transcription factors (NFATc1 and c-Fos) indispensable for osteoclast formation, followed by inhibition of the expression of bone resorption-related genes and proteins (Acp5/TRAcP, CTSK, ATP6V0D2/V-ATPase-d2, and integrin ß3). Furthermore, we examined the underlying mechanisms and found that MA represses osteoclastogenesis by blocking Ca2+ oscillations and the NF-κB and MAPK pathways. In addition, the therapeutic effect of MA on preventing bone loss in vivo was further confirmed in an ovariectomized mouse model. Therefore, considering its ability to inhibit RANKL-mediated osteoclastogenesis and the underlying mechanisms, MA might be a potential candidate for treating osteolytic bone diseases.

Therapeutic Potential of Naringin for Intervertebral Disc Degeneration: Involvement of Autophagy Against Oxidative Stress-Induced Apoptosis in Nucleus Pulposus Cells.

Intervertebral disc degeneration (IDD) is a major cause of lower back pain, but few efficacious medicines have been developed for IDD. Increased nucleus pulposus cells apoptosis is a dominant pathogenesis of IDD and is considered a therapeutic target. Previously, our group proved that autophagy may protect nucleus pulposus cells against apoptosis. As one of the major bioflavonoids of citrus, naringin activates autophagy. Therefore, we hypothesize that naringin may have therapeutic potential for IDD by activating autophagy in nucleus pulposus cells. In this study, we evaluated the effects of naringin on TBHP-induced oxidative stress in nucleus pulposus cells in vitro as well as in puncture-induced rat IDD model in vivo. Our results showed that naringin could reduce the incidence of oxidative stress-induced apoptosis in nucleus pulposus cells and promoted the expression of autophagy markers LC3-II/I and beclin-1. Meanwhile, inhibition of autophagy by 3-MA may partially reverse the anti-apoptotic effect of naringin, indicating that autophagy was involved in the protective effect of naringin in nucleus pulposus cells. Further study showed that autophagy regulation of naringin may be related to AMPK signaling. Also, we found that naringin treatment can regulate the expression of collagen II, aggrecan and Mmp13 to sustain the extracellular matrix. Furthermore, our in vivo study showed that naringin can ameliorate IDD in puncture-induced rat model. In conclusion, our study suggests that naringin can protect nucleus pulposus cells against apoptosis and ameliorate IDD in vivo, the mechanism may relate to its autophagy regulation.

Upregulating mTOR/ERK signaling with leonurine for promoting angiogenesis and tissue regeneration in a full-thickness cutaneous wound model.

Wound therapy remains a clinical challenge due to the poor vascularization during the healing process and the high demand to achieve functional and aesthetically satisfactory scars. Newly-formed blood vessels are necessary for wound healing since they can deliver nutrients and oxygen to the wound area. In this study, the role of leonurine (LN), a traditional Chinese medicine isolated from Herba leonuri, in promoting angiogenesis and its function in wound healing have been investigated. The results of co-culture with human umbilical vein endothelial cells (HUVECs) demonstrated that LN treatment (5-20 µM) could promote the proliferation and migration and enhance the ability of in vitro angiogenesis through up-regulating the mTOR/ERK signaling pathway. Furthermore, a full-thickness cutaneous wound model was used to investigate the healing effect of LN in vivo. Intragastric administration of 20 mg per kg per day LN stimulated the regeneration of more blood vessels at the wound sites, which confirmed the in vitro results of promoting angiogenesis. Due to fast vascularization, the collagen matrix deposition and remodeling processes were also accelerated in LN treated wounds, resulting in efficient wound healing. In summary, LN promoted angiogenesis of endothelial cells in vitro by activating the mTOR/ERK pathway, and could efficiently enhance the angiogenesis and collagen deposition of the regenerated tissue, together with facilitating the wound healing process in vivo. This study provides evidence for LN-stimulated angiogenesis and tissue regeneration in skin wounds, especially in ischemic wounds.

Endoplasmic Reticulum Stress and NF-[Formula: see text]B Pathway in Salidroside Mediated Neuroprotection: Potential of Salidroside in Neurodegenerative Diseases.

Microglial activation leads to increased production of proinflammatory enzymes and cytokines, which is considered to play crucial role in neurodegenerative diseases, however there are only a few drugs that target microglia activation. Recent studies have indicated that the Traditional Chinese Medicine, salidroside (Sal), exerted anti-inflammatory effects. According to this evidence, our present study aims to explore the effect of the Sal (a phenylpropanoid glycoside compound which is isolated from rhodiola), on microglia activation in lipopolysaccharide (LPS)-stimulated BV-2 cells. Our results showed that Sal could significantly inhibit the excessive production of Nitric Oxide (NO) and Prostaglandin E2 (PGE2) in LPS-stimulated BV2 cells. Moreover, Sal treatment could suppress the mRNA and protein expressions of inflammatory enzymes, including Inducible Nitric Oxide Synthase (iNOS) and Cyclooxygenase-2 (COX-2). The mechanisms may be related to the inhibition of the activation of Nuclear Factor-kappaB (NF-[Formula: see text]B) and endoplasmic reticulum stress. Our study demonstrated that salidroside could inhibit lipopolysaccharide-induced microglia activation via the inhibition of the NF-[Formula: see text]B pathway and endoplasmic reticulum stress, which makes it a promising therapeutic agent for human neurodegenerative diseases.