PDGF-BB exhibited therapeutic effects on rat model of bisphosphonate-related osteonecrosis of the jaw by enhancing angiogenesis and osteogenesis.

The mechanism and effective treatment of bisphosphonate-related osteonecrosis of the jaw (BRONJ) are still uncertain. Our previous study revealed that zoledronate (ZOL) preferentially inhibited osteoclasts formation and platelet-derived growth factor-BB (PDGF-BB) secretion, causing suppression of angiogenesis and osteogenesis in vitro. The present study aimed to elucidate whether PDGF-BB had therapeutic effects on rat model of BRONJ by enhancing angiogenesis and angiogenesis. Firstly, rat model of BRONJ was established by ZOL and dexamethasone administration, followed by teeth extraction. The occurrence of BRONJ was confirmed and detected dead bone formation by maxillae examination, micro-CT scan and HE staining (10/10). Compared to control rats (0/10), both angiogenesis and mature bone formation were suppressed in BRONJ-like rats, evidenced by enzyme-linked immunosorbent assay (ELISA) for VEGF (P < 0.01), immunohistochemistry of CD31 (P < 0.05) and OCN (P < 0.01). Moreover, in the early stage of bone healing, the number of preosteoclasts (P < 0.001) and PDGF-BB secretion (P < 0.05) were significantly decreased in bisphosphonates-treated rats, along with the declined numbers of microvessels (P < 0.05) and osteoblasts (P < 0.05). In vitro study, CCK8 assay, alizarin red S staining and western blot assay showed that mandible-derived bone marrow mesenchymal stem cells (BMMSCs) in BRONJ-like rats presented suppressed functions of proliferation, osteogenesis and angiogenesis. Interestingly, recombinant PDGF-BB was able to rescue the impaired functions of BMMSCs derived from BRONJ-like rats at more than 10 ng/ml. Then fibrin sealant with or without recombinant PDGF-BB were tamped into the socket after debridement in BRONJ rats. After 8 weeks, fibrin sealant containing PDGF-BB showed significant therapeutic effects on BRONJ-like rats (bone healing: 8/10 vs 3/10, P < 0.05) with enhancing microvessels and mature bone formation. Our study suggested that the inhibition of angiogenesis and osteogenesis, the potential mechanisms of BRONJ, might partly result from suppression of PDGF-BB secretion in the early stage of bone healing. PDGF-BB local treatment after debridement might avail the healing of BRONJ by increasing angiogenesis and osteogenesis.

EGAR, A Food Protein-Derived Tetrapeptide, Reduces Seizure Activity in Pentylenetetrazole-Induced Epilepsy Models Through α-Amino-3-Hydroxy-5-Methyl-4-Isoxazole Propionate Receptors.

A primary pathogeny of epilepsy is excessive activation of α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors (AMPARs). To find potential molecules to inhibit AMPARs, high-throughput screening was performed in a library of tetrapeptides in silico. Computational results suggest that some tetrapeptides bind stably to the AMPAR. We aligned these sequences of tetrapeptide candidates with those from in vitro digestion of the trout skin protein. Among salmon-derived products, Glu-Gly-Ala-Arg (EGAR) showed a high biological affinity toward AMPAR when tested in silico. Accordingly, natural EGAR was hypothesized to have anticonvulsant activity, and in vitro experiments showed that EGAR selectively inhibited AMPAR-mediated synaptic transmission without affecting the electrophysiological properties of hippocampal pyramidal neurons. In addition, EGAR reduced neuronal spiking in an in vitro seizure model. Moreover, the ability of EGAR to reduce seizures was evaluated in a rodent epilepsy model. Briefer and less severe seizures versus controls were shown after mice were treated with EGAR. In conclusion, the promising experimental results suggest that EGAR inhibitor against AMPARs may be a target for antiepilepsy pharmaceuticals. Epilepsy is a common brain disorder characterized by the occurrence of recurring, unprovoked seizures. Twenty to 30 % of persons with epilepsy do not achieve adequate seizure control with any drug. Here we provide a possibility in which a natural and edible tetrapeptide, EGAR, can act as an antiepileptic agent. We have combined computation with in vitro experiments to show how EGAR modulates epilepsy. We also used an animal model of epilepsy to prove that EGAR can inhibit seizures in vivo. This study suggests EGAR as a potential pharmaceutical for the treatment of epilepsy.

Silibinin inhibits acetylcholinesterase activity and amyloid ß peptide aggregation: a dual-target drug for the treatment of Alzheimer's disease.

Alzheimer's disease (AD) is characterized by amyloid ß (Aß) peptide aggregation and cholinergic neurodegeneration. Therefore, in this paper, we examined silibinin, a flavonoid extracted from Silybum marianum, to determine its potential as a dual inhibitor of acetylcholinesterase (AChE) and Aß peptide aggregation for AD treatment. To achieve this, we used molecular docking and molecular dynamics simulations to examine the affinity of silibinin with Aß and AChE in silico. Next, we used circular dichroism and transmission electron microscopy to study the anti-Aß aggregation capability of silibinin in vitro. Moreover, a Morris Water Maze test, enzyme-linked immunosorbent assay, immunohistochemistry, 5-bromo-2-deoxyuridine double labeling, and a gene gun experiment were performed on silibinin-treated APP/PS1 transgenic mice. In molecular dynamics simulations, silibinin interacted with Aß and AChE to form different stable complexes. After the administration of silibinin, AChE activity and Aß aggregations were down-regulated, and the quantity of AChE also decreased. In addition, silibinin-treated APP/PS1 transgenic mice had greater scores in the Morris Water Maze. Moreover, silibinin could increase the number of newly generated microglia, astrocytes, neurons, and neuronal precursor cells. Taken together, these data suggest that silibinin could act as a dual inhibitor of AChE and Aß peptide aggregation, therefore suggesting a therapeutic strategy for AD treatment.