Sodium Iodate Disrupted the Mitochondrial-Lysosomal Axis in Cultured Retinal Pigment Epithelial Cells.

PURPOSE: Low doses of sodium iodate (NaIO3) impair visual function in experimental animals with selective damage to retinal pigment epithelium (RPE) and serve as a useful model to study diseases caused by RPE degeneration. Mitochondrial dysfunction and defective autophagy have been suggested to play important roles in normal aging as well as many neurodegenerative diseases. In this study, we examined whether NaIO3 treatment disrupted the mitochondrial-lysosomal axis in cultured RPE. METHODS: The human RPE cell line, ARPE-19, was treated with low concentrations (≤500 µM) of NaIO3. The expression of proteins involved in the autophagic pathway and mitochondrial biogenesis was examined with Western blot. Intracellular acidic compartments and lipofuscinogenesis were evaluated by acridine orange staining and autofluorescence, respectively. Mitochondrial mass, mitochondrial membrane potential (MMP), and mitochondrial function were quantified by MitoTracker Green staining, tetramethylrhodamine methyl ester staining, and the MTT assay, respectively. Phagocytosis and the degradation of photoreceptor outer segments (POS) were assessed by fluorescence-based approaches and Western blot against rhodopsin. RESULTS: Treatment with low concentrations of NaIO3 decreased cellular acidity, blocked autophagic flux, and resulted in increased lipofuscinogenesis in ARPE-19 cells. Despite increases in protein levels of Sirtuin 1 and PGC-1α, mitochondrial function was compromised, and this decrease was attributed to disrupted MMP. POS phagocytic activities decreased by 60% in NaIO3-treated cells, and the degradation of ingested POS was also impaired. Pretreatment and cotreatment with rapamycin partially rescued NaIO3-induced RPE dysfunction. CONCLUSIONS: Low concentrations of NaIO3 disrupted the mitochondrial-lysosomal axis in RPE and led to impaired phagocytic activities and degradation capacities.

Total Synthesis of (+)-Medicarpin.

(+)-Medicarpin has been synthesized asymmetrically for the first time in a linear scalable process with an overall yield of 11%. The two chiral centers were constructed in one step via condensation using a chiral oxazolidinone auxiliary. This method will likely accelerate research on medicarpin as an erythropoietin inducer for erythropoietin-deficient diseases.

Activating mitochondrial function and haemoglobin expression with EH-201, an inducer of erythropoietin in neuronal cells, reverses memory impairment.

BACKGROUND AND PURPOSE: Memory impairment can be progressive in neurodegenerative diseases, and physiological ageing or brain injury, mitochondrial dysfunction and oxidative stress are critical components of these issues. An early clinical study has demonstrated cognitive improvement during erythropoietin treatment in patients with chronic renal failure. As erythropoietin cannot freely cross the blood-brain barrier, we tested EH-201 (2,3,5,4'-tetrahydroxystilbene-2-O-ß-d-glucoside, also known as TSG), a low MW inducer of erythropoietin, for its therapeutic effects on memory impairment in models of neurodegenerative diseases, physiological ageing or brain injury. EXPERIMENTAL APPROACH: The effects of EH-201 were investigated in astrocytes and PC12 neuronal-like cells. In vivo, we used sleep-deprived (SD) mice as a stress model, amyloid-ß (Aß)-injected mice as a physiological ageing model and kainic acid (KA)-injected mice as a brain damage model to assess the therapeutic effects of EH-201. KEY RESULTS: EH-201 induced expression of erythropoietin, PPAR-γ coactivator 1α (PGC-1α) and haemoglobin in astrocytes and PC12 neuronal-like cells. In vivo, EH-201 treatment restored memory impairment, as assessed by the passive avoidance test, in SD, Aß and KA mouse models. In the hippocampus of mice given EH-201 in their diet, levels of erythropoietin, PGC-1α and haemoglobin were increased CONCLUSIONS AND IMPLICATIONS: The induction of endogenous erythropoietin in neuronal cells by inducers such as EH-201 might be a therapeutic strategy for memory impairment in neurodegenerative disease, physiological ageing or traumatic brain injury.

Internal ribosome entry site of bFGF is the target of thalidomide for IMiDs development in multiple myeloma.

Although new analogues of immunomodulatory drugs (IMiDs) are being developed for MM, the molecular mechanism of these drugs remains unclear. In the current study, we used MM cell lines as a model to investigate the molecular mechanism of thalidomide and to compare its potency with IMiDs such as pomalidomide. We determined that thalidomide did not inhibit cell proliferation of RPMI8226 and U266 MM cells, whereas pomalidomide showed a significant inhibitory effect on these two MM cell lines. Interestingly, we further demonstrated that although thalidomide down-regulated bFGF translation through the inhibition of IRES even at 0.1 µg/ml, pomalidomide did not have a similar affect bFGF levels. A colony formation assay demonstrated that thalidomide and the bFGF knock-down clones caused a significant reduction in the clonogenic ability of MM cells, and treatment with exogenous bFGF can recover the clonogenic ability of thalidomide-treated cells and knock-down clones, but not that of pomalidomide-treated cells. This implies that thalidomide, but not pomalidomide, targets the IRES of FGF-2. In conclusion, our results highlight a non-cytotoxic anticancer drug target for thalidomide, the IRES of bFGF, and provide the mechanistic rationale for developing IMiDs as anti-cancer therapeutics in MM patients, with improved potency and fewer side effects.

Activation of mitochondrial function and Hb expression in non-haematopoietic cells by an EPO inducer ameliorates ischaemic diseases in mice.

BACKGROUND AND PURPOSE: Many organs suffer from ischaemic injuries that reduce their ability to generate sufficient energy, which is required for functional maintenance and repair. Erythropoietin (EPO) ameliorates ischaemic injuries by pleiotropic effects. The aim of this study was to investigate the effect and mechanism of a small molecule EH-201, and found it as a potent EPO inducer and its effect in non-haematopoietic cells for therapeutic potential in ischemic disorders. EXPERIMENTAL APPROACH: Mice kidney slices, primary hepatocytes, primary cardiomyocytes and C2C12 myoblasts were treated with EH-201. The effects of this treatment on EPO, Hb expression and mitochondrial biogenesis were analysed. In vivo, doxorubicin-induced cardiomyopathic mice were treated with EH-201. The mice were subjected to an endurance test, electrocardiography and echocardiography, and a histological examination of the isolated hearts was performed. EH-201 was also administered to cisplatin-induced nephropathic mice. KEY RESULTS: In non-haematopoietic cells, EH-201 was potent at inducing EPO. EH-201 also stimulated mitochondrial biogenesis and enhanced the expression of Hb by a mechanism dependent on EPO-mediated signalling. In mechanistic studies, using EPO and EPO receptor-neutralizing antibodies, we confirmed that EH-201 enhances EPO-EPOR autocrine activity. EH-201 robustly increased the endurance performance activity of healthy and cardiomyopathic mice during hypoxic stress, enhanced myocardial mitochondrial biogenesis and Hb expression, and also improved cardiac function. EH-201 ameliorated anaemia and renal dysfunction in nephropathic mice. CONCLUSIONS AND IMPLICATIONS: The enhancement and recovery of cellular functions through the stimulation of mitochondrial activity and Hb production in non-haematopoietic cells by an inducer of endogenous EPO has potential as a therapeutic strategy for ischaemic diseases.

Activating mitochondrial regulator PGC-1α expression by astrocytic NGF is a therapeutic strategy for Huntington's disease.

Mitochondrial dysfunction plays an important role in Huntington's disease (HD). NGF gene delivery in AD patients showed an increase in brain energy metabolism and NGF has been shown neuroprotective effects against mitochondrial toxins. However, the role of NGF in regulating mitochondrial function is unclear. Here, we found that NGF-stimulated mitochondrial biogenesis in PC12 and primary neuron cells. Our results demonstrated that peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) is a downstream key target of the NGF signalling pathway. In a 3-nitropropionic acid (3-NP) cell model, NGF treatment rescued the defects in mitochondrial activity and mitochondrial membrane potential. Since NGF cannot freely cross blood-brain barrier, we found an astrocytic NGF inducer, Ganoderma lucidum (GaLu) extract. Its active constituents had potent effects on the induction of NGF in primary astrocytes. Among the identified ingredients, ganoderic acid C2 was most effective. We further found that GaLu-conditioned media can enhance mitochondrial biogenesis in PC12 cells and preventing NGF signalling using NGF antibody or PGC-1α siRNA blocked these effects. Moreover, GaLu and ganoderic acid C2-conditioned media treatment attenuated mitochondrial defects in 3-NP cell model. After 3-NP-induced behavioural impairment and striatal degeneration in mice, GaLu treatment therapeutically restored the behaviour score, sensorimotor ability and neuronal loss. We found that striatal NGF, PGC-1α expression level and succinate dehydrogenase activity were recovered in GaLu-fed mice. These results suggest that the NGF-signalling pathway connected to the mitochondrial regulator, PGC-1α, expression. This signalling triggered by astrocytic NGF with small molecule inducers may offer a therapeutic strategy for HD.

Melatonin attenuates kainic acid-induced neurotoxicity in mouse hippocampus via inhibition of autophagy and α-synuclein aggregation.

In this study, the protective effect of melatonin on kainic acid (KA)-induced neurotoxicity involving autophagy and α-synuclein aggregation was investigated in the hippocampus of C57/BL6 mice. Our data showed that intraperitoneal injection of KA (20 mg/kg) increased LC3-II levels (a hallmark protein of autophagy) and reduced mitochondrial DNA content and cytochrome c oxidase levels (a protein marker of mitochondria). Atg7 siRNA transfection prevented KA-induced LC3-II elevations and mitochondria loss. Furthermore, Atg7 siRNA attenuated KA-induced activation of caspases 3/12 (biomarkers of apoptosis) and hippocampal neuronal loss, suggesting a pro-apoptotic role of autophagy in the KA-induced neurotoxicity. Nevertheless, KA-induced α-synuclein aggregation was not affected in the Atg7 siRNA-transfected hippocampus. The neuroprotective effect of melatonin (50 mg/kg) orally administered 1 hr prior to KA injection was studied. Melatonin was found to inhibit KA-induced autophagy-lysosomal activation by reducing KA-induced increases in LC3-II, lysosomal-associated membrane protein 2 (a biomarker of lysosomes) and cathepsin B (a lysosomal cysteine protease). Subsequently, KA-induced mitochondria loss was prevented in the melatonin-treated mice. At the same time, melatonin reduced KA-increased HO-1 levels and α-synuclein aggregation. Our immunoprecipitation study showed that melatonin enhanced ubiquitination of α-synuclein monomers and aggregates. The anti-apoptotic effect of melatonin was demonstrated by attenuating KA-induced DNA fragmentation, activation of caspases 3/12, and neuronal loss. Taken together, our study suggests that KA-induced neurotoxicity may be mediated by autophagy and α-synuclein aggregation. Moreover, melatonin may exert its neuroprotection via inhibiting KA-induced autophagy and a subsequent mitochondrial loss as well as reducing α-synuclein aggregation by enhancing α-synuclein ubiquitination in the CNS.

Antiosteoporotic Activity of Dioscorea alata L. cv. Phyto through Driving Mesenchymal Stem Cells Differentiation for Bone Formation.

The aim of this study was to evaluate the effect of an ethanol extract of the rhizomes of Dioscorea alata L. cv. Phyto, Dispo85E, on bone formation and to investigate the mechanisms involved. Our results showed that Dispo85E increased the activity of alkaline phosphatase (ALP) and bone nodule formation in primary bone marrow cultures. In addition, Dispo85E stimulated pluripotent C3H10T1/2 stem cells to differentiate into osteoblasts rather than adipocytes. Our in vivo data indicated that Dispo85E promotes osteoblastogenesis by increasing ALP activity and bone nodule formation in both intact and ovariectomized (OVX) mice. Microcomputed tomography (µCT) analysis also showed that Dispo85E ameliorates the deterioration of trabecular bone mineral density (tBMD), trabecular bone volume/total volume (BV/TV), and trabecular bone number (Tb.N) in OVX mice. Our results suggested that Dispo85E is a botanical drug with a novel mechanism that drives the lineage-specific differentiation of bone marrow stromal cells and is a candidate drug for osteoporosis therapy.

Hepatocyte growth factor has a role in the amelioration of diabetic vascular complications via autophagic clearance of advanced glycation end products: Dispo85E, an HGF inducer, as a potential botanical drug.

The aim of this study was to evaluate the effect and elucidate the potential mechanism of the extract of rhizomes from Dioscorea alata L. cv. Phyto, Dispo85E, on accelerating the elimination of advanced glycation end products (AGEs) in vitro and in vivo. Primary mouse nonparenchymal cells (NPCs) were used to evaluate the drug effect on AGEs clearance and autophagic-lysosomal activity. In an animal study, we used AGEs-induced diabetic mice to evaluate the drug effect on AGEs-induced vascular complications. Our results indicated that Dispo85E enhanced the endocytosis and degradation activity of AGEs in hepatic NPCs. Furthermore, the hepatocyte growth factor (HGF) expression level was positively correlated with the clearance capacity of the AGEs in NPCs after Dispo85E treatment. In addition, the effects of Dispo85E on the degradation and uptake capability of (14)C-AGEs were abolished in the presence of an anti-HGF neutralizing antibody. We further demonstrated that recombinant mouse HGF could enhance the endocytosis and autophagic clearance of AGEs in NPCs. The in vivo data indicated that Dispo85E increased hepatic HGF messenger RNA expression levels and decreased serum AGEs level in diabetic mice. Moreover, the function of retina and kidneys was improved by Dispo85E treatment in AGEs-induced diabetic mice. These results suggest that HGF may have an important role in the elimination of AGEs. This study suggests that Dispo85E is a botanical drug with a novel mechanism that enhances the clearance of AGEs through HGF-induced autophagic-lysosomal pathway and is a candidate drug for the treatment of diabetic vascular complications.

The G-rich promoter and G-rich coding sequence of basic fibroblast growth factor are the targets of thalidomide in glioma.

Thalidomide is considered to be a potent antiangiogenic and immunomodulatory drug for cancer therapy. Earlier clinical studies have found that patients responding to this drug often had high plasma levels of basic fibroblast growth factor (bFGF). This cytokine is a proangiogenic factor overexpressed in many tumors and is also a regulator of limb development; hence, it might be a target of thalidomide. Using U-87 MG cell lines, we found that thalidomide, especially when encapsulated in a liposome, down-regulated the transcription and translation of the FGF-2 gene by interacting with G-rich regions present in the promoter and the internal ribosome entry site of its transcript at concentrations much lower than therapeutic serum concentrations. Thalidomide treatment also dramatically suppressed the anchorage-independent growth of U-87 MG and other glioma cells by over a thousand fold without affecting its anchorage-dependent growth, which may be accomplished by knocking down endogenous bFGF expression in these cells. Accordingly, the addition of recombinant bFGF partially restored the anchorage-independent growth of these cells. Our data suggest that by targeting the G-rich regions of bFGF, thalidomide (at 0.1 microg/mL) can reduce cellular bFGF levels and affect tumor anchorage-independent growth, the hallmark of tumorigenicity. Our results are promising for future clinical investigations using low doses of thalidomide.

Chinese herb Radix Polygoni Multiflori as a therapeutic drug for liver cirrhosis in mice.

Liver regeneration not only plays a functional role in directing the restoration of liver mass after resection or injury, but also may have participated in effective therapy of liver cirrhosis. Additionally, hepatocyte growth factor (HGF) appears to be a factor of great importance in liver regeneration and attenuated progression of experimental liver cirrhosis. The aim of this study is to use Radix Polygoni Multiflori (POMU) extract, a Chinese herb traditionally used for liver-protective therapy, as a reagent for the evaluation of its potential medicinal use in liver cirrhosis. We used in vitro coculture system to show that POMU could promote the expression of HGF by hepatic nonparenchymal cells, consequently the proliferation of primary liver cells and phagocytic activity of Kupffer cells using fluorescein-labeled Escherichia coli as the target, and inhibit the proliferation of stellate cells. Using dimethylnitrosamine-induced liver cirrhosis animal, POMU even at 20 mg/(kg day) dosage, was illustrated to reverse the pathogenic progression of the disease, decrease the hydroxyproline content and increases the expression of HGF messenger RNA in liver tissue. The survival rate was significantly increased in the POMU-treated animal. In conclusion, our study showed the promise of POMU in the medicinal use for the treatment of liver cirrhosis.

Oligomerization of acidic fibroblast growth factor is not a prerequisite for its cell proliferation activity.

Oligomerization of fibroblast growth factors (FGFs) induced on binding to heparin or heparan sulfate proteoglycan is considered to be crucial for receptor activation and initiation of biological responses. To gain insight into the mechanism of activation of the receptor by FGFs, in the present study we investigate the effect(s) of interaction of a heparin analog, sucrose octasulfate (SOS), on the structure, stability, and biological activities of a recombinant acidic FGF from Notophthalmus viridescens (nFGF-1). SOS is found to bind to nFGF-1 and significantly increase the thermodynamic stability of the protein. Using a variety of techniques such as size-exclusion chromatography, sedimentation velocity, and multidimensional nuclear magnetic resonance (NMR) spectroscopy, it is shown that binding of SOS to nFGF-1 retains the protein in its monomeric state. In its monomeric state (complexed to SOS), n-FGF-1 shows significant cell proliferation activity. (15)N and (1)H chemical shift perturbation and the intermolecular nuclear Overhauser effects (NOEs) between SOS and nFGF-1 reveal that the ligand binds to the dense, positively charged cluster located in the groove enclosed by beta-strands 10 and 11. In addition, molecular modeling based on the NOEs observed for the SOS-nFGF-1 complex, indicates that SOS and heparin share a common binding site on the protein. In conclusion, the results of the present study clearly show that heparin-induced oligomerization of nFGF-1 is not mandatory for its cell proliferation activity.

Induction of differentiation in rat C6 glioma cells with Saikosaponins.

The effects of saikosaponins (a, b(1), b(2), c, d), isolated from Bupleurum Radix, on the induction of differentiation in rat C6 glioma cells were studied. Saikosaponins a and d were shown to inhibit cell proliferation and alter cell morphology. In addition to cytostasis, the enzymatic activities of glutamine synthetase (GS) and 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) were also noticeably increased after treatment with saikosaponin a. Nevertheless, saikosaponin d only showed an increase of GS activity, no significant changes in CNP activity were found. These results suggest that saikosaponin a can induce the differentiation of C6 glioma cells into astrocytes and/or oligodendrocytes, but saikosaponin d can only induce the differentiation of C6 glioma cells into astrocytes.