Glia-derived Neurotrophic Factor Research Articles

Multi-platform analysis revealed the substance basis and mechanism of Wei-Tong-Xin in ameliorating ENS dysfunction for dyspepsia treatment

Ethnopharmacological relevanceDuodenal motility disorder is a contributing factor to dyspepsia. The traditional Chinese medicine (TCM) formula Wei-Tong-Xin (WTX), originated from the famous ancient Chinese formula “Wan Ying Yuan”, has been demonstrated efficacy in alleviating dyspepsia. Aim of the studyThe current study aims to elucidate the chemical composition of WTX to establish the pharmacodynamic material basis. On the basis of component, in depth to illuminate the mechanism by which WTX treats dyspepsia via constructing the comprehensive analysis of multi-platform. Materials and methodsThe chemical constituents of WTX were systematically analyzed by UHPLC-Q-TOF-MS/MS data processing methods. Based on this, network pharmacology was employed to predict the mechanism by which WTX improved dyspepsia. The dyspepsia mouse model was constructed, and histopathology as well as intestinal permeability were assessed using H&E staining, PAS staining and FITC-dextran assay. Protein expression was detected using Western blot, immunofluorescence, immunohistochemistry and ELISA kits. ResultsA total of 100 chemical components of WTX were preliminarily identified. Network pharmacological analysis indicated that the therapeutic mechanism of WTX in treating dyspepsia may be related to the regulation of inflammation and oxidative stress-related signaling pathways. In vivo studies showed that WTX mitigated duodenal inflammation and oxidative stress responses, repairing the intestinal mucosal barrier damaged by cisplatin (CIS). Additionally, WTX restored the number of glial cells diminished by inflammatory damage, and ameliorated the serotoninergic neuronal dysfunction caused by insufficient secretion of glia-derived neurotrophic factor (GDNF), and enhanced intestinal transit. ConclusionsIn this study, a total of 100 components of the WTX extract were identified through literature review and mass spectrometry database search. Utilizing computer technology, in conjunction with pharmacodynamic and mechanistic studies, WTX has been found to restore serotoninergic neuronal function by reducing intestinal mucosal inflammatory and oxidative damage, ultimately promoting intestinal transport and treating dyspepsia.

Glioprotective Effects of Sulforaphane in Hypothalamus: Focus on Aging Brain.

Sulforaphane is a natural compound with neuroprotective activity, but its effects on hypothalamus remain unknown. In line with this, astrocytes are critical cells to maintain brain homeostasis, and hypothalamic astrocytes are fundamental for sensing and responding to environmental changes involved in a variety of homeostatic functions. Changes in brain functionality, particularly associated with hypothalamic astrocytes, can contribute to age-related neurochemical alterations and, consequently, neurodegenerative diseases. Thus, here, we investigated the glioprotective effects of sulforaphane on hypothalamic astrocyte cultures and hypothalamic cell suspension obtained from aged Wistar rats (24months old). Sulforaphane showed anti-inflammatory and antioxidant properties, as well as modulated the mRNA expression of astroglial markers, such as aldehyde dehydrogenase 1 family member L1, aquaporin 4, and vascular endothelial growth factor. In addition, it increased the expression and extracellular levels of trophic factors, such as glia-derived neurotrophic factor and nerve growth factor, as well as the release of brain-derived neurotrophic factor and the mRNA of TrkA, which is a receptor associated with trophic factors. Sulforaphane also modulated the expression of classical pathways associated with glioprotection, including nuclear factor erythroid-derived 2-like 2, heme oxygenase-1, nuclear factor kappa B p65 subunit, and AMP-activated protein kinase. Finally, a cell suspension with neurons and glial cells was used to confirm the predominant effect of sulforaphane in glial cells. In summary, this study indicated the anti-aging and glioprotective activities of sulforaphane in aged astrocytes.

Platelet-rich plasma-derived exosomes boost mesenchymal stem cells to promote peripheral nerve regeneration

Peripheral nerve injury (PNI) remains a severe clinical problem with debilitating consequences. Mesenchymal stem cell (MSC)-based therapy is promising, but the problems of poor engraftment and insufficient neurotrophic effects need to be overcome. Herein, we isolated platelet-rich plasma-derived exosomes (PRP-Exos), which contain abundant bioactive molecules, and investigated their potential to increase the regenerative capacity of MSCs. We observed that PRP-Exos significantly increased MSC proliferation, viability, and mobility, decreased MSC apoptosis under stress, maintained MSC stemness, and attenuated MSC senescence. In vivo, PRP-Exo-treated MSCs (pExo-MSCs) exhibited an increased retention rate and heightened therapeutic efficacy, as indicated by increased axonal regeneration, remyelination, and recovery of neurological function in a PNI model. In vitro, pExo-MSCs coculture promoted Schwann cell proliferation and dorsal root ganglion axon growth. Moreover, the increased neurotrophic behaviour of pExo-MSCs was mediated by trophic factors, particularly glia-derived neurotrophic factor (GDNF), and PRP-Exos activated the PI3K/Akt signalling pathway in MSCs, leading to the observed phenotypes. These findings demonstrate that PRP-Exos may be novel agents for increasing the ability of MSCs to promote neural repair and regeneration in patients with PNI.

Protective Effects of Flavonoid Rutin Against Aminochrome Neurotoxicity.

Causes of dopaminergic neuronal loss in Parkinson's disease (PD) are subject of investigation and the common use of models of acute neurodegeneration induced by neurotoxins 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 6-hydroxydopamine, and rotenone contributed to advances in the study of PD. However, the use of study models more similar to the pathophysiology of PD is required for advances in early diagnosis and translational pharmacology. Aminochrome (AMI), a compound derived from dopamine oxidation and a precursor of neuromelanin, is able to induce all the mechanisms associated with neurodegeneration. Previously, we showed AMI is cytotoxic in primary culture of mesencephalic cells (PCMC) and induces in vitro and in vivo neuroinflammation. On the other hand, the effect of rutin in central nervous system cells has revealed anti-inflammatory, antioxidative, and neuroprotective potential. However, there have been no data studies on the effect of rutin against aminochrome neurotoxicity. Here, we show that rutin prevents lysosomal dysfunction and aminochrome-induced cell death in SHSY-5Y cells, protects PCMC against aminochrome cytotoxicity, and prevents in vivo loss of dopaminergic neurons in substantia nigra pars compacta (SNPc), as well as microgliosis and astrogliosis. Additionally, we show that rutin decreases levels of interleukin-1β (IL-1β) mRNA and increases levels of glia-derived neurotrophic factor (GDNF) and nerve-derived neurotrophic factor (NGF) mRNA. We evidence for the first time the protective effect of rutin on PD aminochrome-induced models and suggest the potential role of the anti-inflammatory activity and upregulation of NGF and GDNF in the mechanism of rutin action against aminochrome neurotoxicity.

New Concepts of the Interplay Between the Gut Microbiota and the Enteric Nervous System in the Control of Motility.

Propulsive gastrointestinal (GI) motility is critical for digestive physiology and host defense. GI motility is finely regulated by the intramural reflex pathways of the enteric nervous system (ENS). The ENS is in turn regulated by luminal factors: diet and the gut microbiota. The gut microbiota is a vast ecosystem of commensal bacteria, fungi, viruses, and other microbes. The gut microbiota not only regulates the motor programs of the ENS but also is critical for the normal structure and function of the ENS. In this chapter, we highlight recent research that has shed light on the microbial mechanisms of interaction with the ENS involved in the control of motility. Toll-like receptor signaling mechanisms have been shown to maintain the structural integrity of the ENS and the neurochemical phenotypes of enteric neurons, in part through the production of trophic factors including glia-derived neurotrophic factor. Microbiota-derived short-chain fatty acids and/or single-stranded RNA regulates the synthesis of serotonin in enterochromaffin cells, which are involved in the initiation of enteric reflexes, among other functions. Further evidence suggests a crucial role for microbial modulation of serotonin in maintaining the integrity of the ENS through enteric neurogenesis. Understanding the microbial pathways of enteric neural control sheds new light on digestive health and provides novel treatment strategies for GI motility disorders.

Sigma–1 receptor activation alleviates blood–brain barrier disruption post cerebral ischemia stroke by stimulating the GDNF–GFRα1–RET pathway

Blood–brain barrier (BBB) disruption is one of the most important pathological manifestations of ischemic stroke. Reducing BBB collapse is effective in alleviating brain parenchymal injury and cognitive dysfunction. Our previous study reported that Sigma–1 receptor (Sig–1R) activation in cerebral microvascular endothelial cells (CMECs) ameliorated BBB impairment, but the detailed mechanism remains unclear. In this study, we investigated Sig–1R activation as a BBB integrity promoter via many post ischemic stroke pathways. Sig–1R activation in BBB–associated astrocytes can increase glia–derived neurotrophic factor (GDNF) secretion in bilateral common carotid artery occlusion (BCCAO) mice. Upregulated GDNF activates its receptors in CMECs to promote BBB integrity, and activated Sig–1R in CMECs facilitates this process. In vitro experiments have found that Sig–1R activation in CMECs promotes the interaction between the GDNF α1 receptor and transduction rearrangement gene, increasing PI3K–AKT–junction protein signaling pathway expression. Sig–1R activation could be an effective therapeutic method for preventing BBB damage in ischemic stroke and other neurological conditions.

ELISA-based quantification of neurotrophic growth factors in urine from prostate cancer patients.

Non‐invasive procedures are needed for prostate cancer management, and urine represents a potential source of new biomarkers with translational value. Recent evidence has shown that the growth of new nerves in the tumor microenvironment is essential to prostate cancer progression. Neurotrophic growth factors are expressed by prostate cancer cells and contribute to prostate tumor innervation, but their presence in urine is unclear. In the present study, we have assayed the concentration of neurotrophic factors in the urine of prostate cancer patients. Urine was collected from a prospective cohort of 45 men with prostate cancer versus 30 men without cancer and enzyme‐linked immunosorbent assay was used to quantify nerve growth factor (NGF) and its precursor proNGF, brain‐derived neurotrophic factor (BDNF) and proBDNF, neurotrophin‐3, neurotrophin‐4/5, and glia‐derived neurotrophic growth factor. The results show that neurotrophic factors are detectable in various concentrations in both cancer and healthy urine, but no significant difference was found. Also, no association was observed between neurotrophic factor concentrations and prostate cancer grade. This study is the first quantification of neurotrophins in urine, and although no significant differences were observed between prostate cancer patients versus those without prostate cancer, or between prostate cancers of various grades, the potential value of neurotrophins for prostate cancer diagnosis and prognosis warrants further investigations in larger patient cohorts.

A graphene oxide-copper nanocomposite for the regeneration of the dentin-pulp complex: An odontogenic and neurovascularization-inducing material

• Well-dispersed water soluble graphene oxide-copper nanocomposites is synthesized. • The GO-Cu can promote odontogenesis of DPSCs. • Odontogenesis and neurovascularization was observed in regenerated dentin-pulp-like tissues. Dentin–pulp complex tissue engineering is a promising novel therapy in endodontics. Materials currently used in regenerative endodontics, e.g., calcium hydroxide and mineral trioxide aggregate, do not ensure full regeneration of the dentin–pulp complex, especially in terms of neurovascular induction. In this study, we fabricated a water-soluble graphene oxide–copper nanocomposite (GO-Cu) and investigated its odontogenic and neurovascularization-inducing abilities by means of dental pulp stem cells (DPSCs). Low-dose (≤10 µg/mL) GO-Cu had no effect on DPSC viability and promoted proliferation and adhesion. DPSCs treated with GO-Cu differentiated into odontoblasts and secreted larger amounts of vascular endothelial growth factor (VEGF) and glia-derived neurotrophic factor (GDNF) just as when they were cultured on a GO-Cu–coated calcium phosphate cement (CPC/GO-Cu) scaffold. Human umbilical vein endothelial cells treated with GO-Cu showed more tube formation, higher VEGF expression, and a stronger migratory ability. In addition, immunomodulatory genes, including indoleamine 2,3-dioxygenase (IDO), human leukocyte antigen G (HLA-G), and hepatocyte growth factor (HGF), were upregulated in DPSCs by the GO-Cu treatment. When CPC/GO-Cu was transplanted subcutaneously into nude mice, dentin–pulp complex–like structures formed expressing dentin sialophosphoprotein (DSPP), CD31, and GAP43, and the mineralized area and blood vessel numbers were greater in the CPC/GO-Cu group than CPC-alone group. These results show odontogenic and neurovascularization-inducing abilities of GO-Cu and suggest its promising application in regenerative endodontics.

α‑synuclein induces apoptosis of astrocytes by causing dysfunction of the endoplasmic reticulum‑Golgi compartment.

Although previous work has demonstrated that the overexpression of wild-type or mutant α-synuclein (α-syn) can induce cell death via a number of different mechanisms, including oxidative stress, dysfunction of the ubiquitin-proteasome degradation system, mitochondrial damage and endoplasmic reticulum (ER) stress, research interest has primarily focused on neurons. However, there is accumulating evidence that suggests that astrocytes may be involved in the earliest changes, as well as the progression of Parkinson's disease (PD), though the role of α-syn in astrocytes has not been widely studied. In the present study, it was revealed that the mutant α-syn (A53T and A30P) in astrocytes triggered ER stress via the protein kinase RNA-like ER kinase/eukaryotic translation initiation factor 2α signaling pathway. Astrocyte apoptosis was induced through a CCAAT-enhancer-binding protein homologous protein-mediated pathway. In addition, Golgi fragmentation was observed in the process. On the other hand, it was also demonstrated, in a primary neuronal-astroglial co-culture system, that the overexpression of α-syn significantly decreased the levels of glia-derived neurotrophic factor (GDNF) and partly inhibited neurite outgrowth. Although direct evidence is currently lacking, it was proposed that dysfunction of the ER-Golgi compartment in astrocytes overexpressing α-syn may lead to a decline of GDNF levels, which in turn would suppress neurite outgrowth. Taken together, the results of the present study offer further insights into the pathogenesis of PD from the perspective of astrocytes, which may provide novel strategies for the diagnosis and treatment of PD in the future.

Remyelination improvement after neurotrophic factors secreting cells transplantation in rat spinal cord injury.

Objective(s):Neurotrophic factors secreting cells (NTS-SCs) may be a superior cell source for cell-based therapy in neurodegenerative diseases. NTS-SCs are able to secrete some neurotrophic Such as nerve growth factor and glia-derived neurotrophic factor. Our primary aim was to assess transplantation of neurotrophic factor secreting cells derived from human adipose-derived stem cells (hADSCs) into the damaged spinal cord rats and determine the potential of these cells in remyelination.Materials and Methods:To this end, 40 adult male Wistar rats were categorized into four groups including; control, lysolecithin (Lysophosphatidylcholines or LPC), vehicle, and NTS-SCs transplan-tation. Local demyelination was induced using LPC injection into the lateral column of spinal cord. Seven days after the lysolecithin lesion, the cells transplantation was performed. The ultrastructure of myelinated fibers was examined with a transmission electron microscope to determine the extent of myelin destruction and remyelinization 4 weeks post cell transplantation. Moreover, the presence of oligodendrocyte in the lesion of spinal cord was assessed by immunohistochemistry procedure.Results:The results of current study indicated that in NTF-SCs transplantation group, the remyelination process and the mean of myelin sheath thickness as well as axonal diameters were significantly higher than other groups (P<0.001). Furthermore, immunohistochemistry analysis revealed that in NTF-SCs transplantation group more than 10 percent of transplanted cells were positive for specific markers of oligodendrocyte cells.Conclusion:NTF-SCs transplantation represents a valuable option for cell-based therapy in the nervous tissue damages.

Hippocampal Astrocyte Cultures from Adult and Aged Rats Reproduce Changes in Glial Functionality Observed in the Aging Brain.

Astrocytes are dynamic cells that maintain brain homeostasis, regulate neurotransmitter systems, and process synaptic information, energy metabolism, antioxidant defenses, and inflammatory response. Aging is a biological process that is closely associated with hippocampal astrocyte dysfunction. In this sense, we demonstrated that hippocampal astrocytes from adult and aged Wistar rats reproduce the glial functionality alterations observed in aging by evaluating several senescence, glutamatergic, oxidative and inflammatory parameters commonly associated with the aging process. Here, we show that the p21 senescence-associated gene and classical astrocyte markers, such as glial fibrillary acidic protein (GFAP), vimentin, and actin, changed their expressions in adult and aged astrocytes. Age-dependent changes were also observed in glutamate transporters (glutamate aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1)) and glutamine synthetase immunolabeling and activity. Additionally, according to in vivo aging, astrocytes from adult and aged rats showed an increase in oxidative/nitrosative stress with mitochondrial dysfunction, an increase in RNA oxidation, NADPH oxidase (NOX) activity, superoxide levels, and inducible nitric oxide synthase (iNOS) expression levels. Changes in antioxidant defenses were also observed. Hippocampal astrocytes also displayed age-dependent inflammatory response with augmentation of proinflammatory cytokine levels, such as TNF-α, IL-1β, IL-6, IL-18, and messenger RNA (mRNA) levels of cyclo-oxygenase 2 (COX-2). Furthermore, these cells secrete neurotrophic factors, including glia-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), S100 calcium-binding protein B (S100B) protein, and transforming growth factor-β (TGF-β), which changed in an age-dependent manner. Classical signaling pathways associated with aging, such as nuclear factor erythroid-derived 2-like 2 (Nrf2), nuclear factor kappa B (NFκB), heme oxygenase-1 (HO-1), and p38 mitogen-activated protein kinase (MAPK), were also changed in adult and aged astrocytes and are probably related to the changes observed in senescence marker, glutamatergic metabolism, mitochondrial dysfunction, oxidative/nitrosative stress, antioxidant defenses, inflammatory response, and trophic factors release. Together, our results reinforce the role of hippocampal astrocytes as a target for understanding the mechanisms involved in aging and provide an innovative tool for studies of astrocyte roles in physiological and pathological aging brain.

Role of c-Jun N-terminal kinase in late nerve regenerationmonitored by invivo imaging of thy1-yellow fluorescent protein transgenic mice.

The restoration of function to injured peripheral nerves separated by a gap requires regeneration across it and reinnervation to target organs. To elucidate these processes, we have established an invivo monitoring system of nerve regeneration in thy1-yellow fluorescent protein transgenic mice expressing a fluorescent protein in their nervous system. Here we demonstrated that motor and sensory nerves were regenerated in a coordinated fashion across the gap and that the functional recovery of the response to mechanical stimuli correlated well with sensory innervation to the foot. Among the mitogen-activated protein kinase inhibitors examined, only the c-Jun N-terminal kinase (JNK) inhibitors delayed functional recovery. Although it did not affect the reinnervation of the muscle, the JNK inhibitor delayed sensory nerve innervation to the skin for over 8weeks and increased the expression of activatng transcription factor 3 (ATF3), a neuronal injury marker, in the dorsal root ganglion over the same time period. Antibodies against nerve growth factor, glia-derived neurotrophic factor, and brain-derived neurotrophic factor applied to the transection site delayed the functional recovery in this order of potency. These neurotrophic factors enhanced neurite outgrowth from cultured dorsal root ganglion neurons, and the JNK inhibitor reversed their stimulatory effects. These results suggest that JNK played roles in nerve regeneration at both early and late phases. Taken together, the present study demonstrated that neurotrophic factors released from the distal nerve may accelerate motor and sensory nerve regeneration across the gap in a coordinated fashion and reinnervation of the target organs independently. The model characterized here has the advantage of invivo monitoring of the evaluation of morphological and functional recovery in the same mice for a long period of time.

Combination effect of memantine and mesenchymal stem cells on the recovery of brain damage in a rat model of brain ischemia

Whether the transplantation of neural progenitor cells (NPCs) derived from mesenchymal stem cells combined with memantine enhanced neuroprotective effects in an animal model of stroke was investigated. In combination therapy groups, significant reduction of infarct volume and improvement of neurological functions were observed at 3 days after middle cerebral artery occlusion (MCAO) compared to monotherapy. Co-administration of memantine and NPCs enhanced the antiapoptotic effect and reduced the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells compared to the NPCs alone group at 7 days after MCAO. Intracarotid transplanted NPCs were localized to the ischemic boundary zone. Moreover, the number of transplanted NPCs on day 7 with combination therapy was significantly higher than those of NPCs monotherapy. Memantine and the combination of memantine + NPCs induced the expression of endogenous neurotrophic factor genes brain-derived neurotrophic factor, nerve growth factor, and glia-derived neurotrophic factor and also upregulated Arc (activity-regulated cytoskeleton associated protein). These effects might be responsible for the induced survival of NPCs and improved functional behavior. These finding indicates that combination therapy of memantine and NPCs enhances neuroprotection against ischemic brain injury.

Antagonistic interactions between dexamethasone and fluoxetine modulate morphodynamics and expression of cytokines in astrocytes

The “plasticity hypothesis” proposes that major depression is caused by morphological and biochemical modifications in neurons and astrocytes and those beneficial pharmacological effects of selective-serotonin-reuptake-inhibitors (SSRI) are at least partially associated with modifications of cellular communications between these cells. In this study we examined effects of the antidepressant fluoxetine on cultured astrocytes that were, in some cases, pretreated with dexamethasone, a cortisol analog known to trigger depressive disorder.Primary rat astrocytes were purified and treated with dexamethasone and the SSRI fluoxetine in physiological concentrations so that both drugs did not affect cell viability. Expression of interleukin-2 (IL-2) and glia-derived-neurotrophic-factor (GDNF) were analyzed and monitored and cell viability, apoptosis, cluster formation, particle-removing capacity and cell mobility were also monitored.Pre-studies without any drugs on mixed neuron-astrocyte co-cultures suggested that astrocytes interacted with neurons and other brain cells in vitro by actively assembling them into clusters. Treatment of purified astrocytes with dexamethasone significantly decreased their mobility compared to controls but had no effect on cluster formation. Dexamethasone-treated cells removed fewer extracellular particles derived from dead cells and cell debris. Both effects were abolished by simultaneous application of fluoxetine. Intracellular IL-2 increased, while GDNF amount expression was diminished following dexamethasone treatment. Simultaneous administration of fluoxetine reversed dexamethasone-triggered IL-2 elevation but had no effect on decreased GDNF concentration.These results suggest that mobility and growth factor equilibrium of astrocytes are affected by dexamethasone and by fluoxetine and that fluoxetine could reverse some changes induced by dexamethasone.

Etifoxine promotes glia-derived neurite outgrowth in vitro and in vivo.

Peripheral nerve injuries usually require a graft to facilitate axonal regeneration into the distal nerve stump. Acellular nerve grafts are good candidates for nerve repair, but clinical outcomes from grafts are not always satisfactory. Etifoxine is a ligand of the 18-kDa translocator protein (TSPO) and has been demonstrated to serve multiple functions in nervous system. This study aimed to determine the optimal concentration of etifoxine for neurite outgrowth using PC12 cells and verify whether etifoxine could enhance in vivo peripheral nerve regeneration. PC12 cells were exposed to various concentrations of etifoxine (5, 10, 20, and 40 µM). Neuronal-like outgrowth and glia-derived neurotrophic factor (GDNF) mRNA expression were measured, and a rat sciatic nerve transection model was employed. Histological examination was used to evaluate the efficacy of nerve regeneration, and real-time polymerase chain reaction (PCR) evaluated changes in mRNA levels after etifoxine treatment. Our data show that etifoxine increased neuronal-like outgrowth in PC12 cells in a dose-dependent manner; however, GDNF expression peaked at 20 µM etifoxine (1.97-fold increase compared with control, p = 0.0046). In vivo studies demonstrated that etifoxine improved sciatic nerve regeneration, modulated immune responses, and boosted neurotrophin expression. Because of etifoxine's adverse effects, we suggest an optimal etifoxine concentration of 20 µM. Its beneficial role may lie in increased neurotrophin expression, and etifoxine may be a promising therapeutic for patients with peripheral nerve injuries.

66 Neural Stem Cell Transplantation Restored the Delayed Gastric Emptying in Apolipoprotein E-Knockout Mice

Background. Although the pathogenesis of delayed gastric emptying, namely gastroparesis, is still unclear, diabetes mellitus is major etiology of gastroparesis. Decreased neuronal nitric oxide synthase (nNOS), which induces relaxation of gastric smooth muscle through the production of nitric oxide, is supposed to be one of the mechanisms of gastroparesis (Gastroenterology 113:1535, 1997). However, the effective treatment for gastroparesis has not been developed. While dyslipidemia is a risk factor of diabetic neuropathy, the defect of apolipoprotein E (apoE), a lipid transporter secreted from glial cell, decreased the expression of nNOS in the stomach (Dig Dis Sci. 57:1504, 2012). Furthermore, transplantion of neural stem cell into gastric antral wall was reported to improve delayed gastric emptying in nNOS knockout mouse (Gastroenterology 129:1817, 2005). The aim of the present study is to explore the role of apoE on gastric emptying and evaluate the effect of neural stem cell transplantation against the model of gastroparesis. Methods. The model of type2 diabetes, db/db mice, and apoE knockout mice, which is the model of arteriosclerosis and hyperlipidemia, were used. For measurement of gastric emptying, 0.48 mg of 13C-acetic acid with 0.15 ml liquid meal (Lacol®) was orally administered. The gastric half emptying time (t1/2) measured by 13C breath test was used for evaluation. The expression levels of nNOS, pan-neuronal marker, PGP 9.5, glial fibrillary acidic protein (GFAP), and glia derived neurotrophic factor (GDNF) were examined by immunohistochemistry andWestern blotting. Neural stem cells were isolated from ffLuc-transgenic mouse, which fluorescent protein, venus, and luciferase gene was fused (BBRC 419; 188, 2012). After tertiary neurosphere was formed, it was injected into gastric antral wall by glass needle. Results. Delayed gastric emptying was observed in 27% of db/db mice, while the levels of blood glucose and body weight were not significantly different. The expression of nNOS in gastric antrum and serum level of apoE were significantly decreased in db/db mice which presented delayed gastric emptying. In apoE knockout mice, the gastric emptying was also delayed compared with control. Although, the expression of PGP 9.5 was not changed, the expression of nNOS was significantly decreased in apoE knockout mice. Furthermore, the expression levels of GFAP and GDNF were significantly decreased in apoE knockout mice. Transplantation of neural stem cell significantly improved the delayed gastric emptying in apoE knockout mice. Conclusion. Neural stem cell transplantation restored the delayed gastric emptying in apoE knockout mice, suggesting a promising application of regenerative therapy against gastroparesis.

67 Perturbing NMDA Receptor -PSD-95 Protein Interactions Prevents Selective Loss of Nitric Oxide Synthase (NOS) Containing Neuron and Improves Gastric Emptying in Diabetic Rats

Background. Although the pathogenesis of delayed gastric emptying, namely gastroparesis, is still unclear, diabetes mellitus is major etiology of gastroparesis. Decreased neuronal nitric oxide synthase (nNOS), which induces relaxation of gastric smooth muscle through the production of nitric oxide, is supposed to be one of the mechanisms of gastroparesis (Gastroenterology 113:1535, 1997). However, the effective treatment for gastroparesis has not been developed. While dyslipidemia is a risk factor of diabetic neuropathy, the defect of apolipoprotein E (apoE), a lipid transporter secreted from glial cell, decreased the expression of nNOS in the stomach (Dig Dis Sci. 57:1504, 2012). Furthermore, transplantion of neural stem cell into gastric antral wall was reported to improve delayed gastric emptying in nNOS knockout mouse (Gastroenterology 129:1817, 2005). The aim of the present study is to explore the role of apoE on gastric emptying and evaluate the effect of neural stem cell transplantation against the model of gastroparesis. Methods. The model of type2 diabetes, db/db mice, and apoE knockout mice, which is the model of arteriosclerosis and hyperlipidemia, were used. For measurement of gastric emptying, 0.48 mg of 13C-acetic acid with 0.15 ml liquid meal (Lacol®) was orally administered. The gastric half emptying time (t1/2) measured by 13C breath test was used for evaluation. The expression levels of nNOS, pan-neuronal marker, PGP 9.5, glial fibrillary acidic protein (GFAP), and glia derived neurotrophic factor (GDNF) were examined by immunohistochemistry andWestern blotting. Neural stem cells were isolated from ffLuc-transgenic mouse, which fluorescent protein, venus, and luciferase gene was fused (BBRC 419; 188, 2012). After tertiary neurosphere was formed, it was injected into gastric antral wall by glass needle. Results. Delayed gastric emptying was observed in 27% of db/db mice, while the levels of blood glucose and body weight were not significantly different. The expression of nNOS in gastric antrum and serum level of apoE were significantly decreased in db/db mice which presented delayed gastric emptying. In apoE knockout mice, the gastric emptying was also delayed compared with control. Although, the expression of PGP 9.5 was not changed, the expression of nNOS was significantly decreased in apoE knockout mice. Furthermore, the expression levels of GFAP and GDNF were significantly decreased in apoE knockout mice. Transplantation of neural stem cell significantly improved the delayed gastric emptying in apoE knockout mice. Conclusion. Neural stem cell transplantation restored the delayed gastric emptying in apoE knockout mice, suggesting a promising application of regenerative therapy against gastroparesis.

Naringin protects the nigrostriatal dopaminergic projection through induction of GDNF in a neurotoxin model of Parkinson's disease

This study investigated the effect of naringin, a major flavonoid in grapefruit and citrus fruits, on the degeneration of the nigrostriatal dopaminergic (DA) projection in a neurotoxin model of Parkinson's disease (PD) in vivo and the potential underlying mechanisms focusing on the induction of glia-derived neurotrophic factor (GDNF), well known as an important neurotrophic factor involved in the survival of adult DA neurons. 1-Methyl-4-phenylpyridinium (MPP+) was unilaterally injected into the medial forebrain bundle of rat brains for a neurotoxin model of PD in the presence or absence of naringin by daily intraperitoneal injection. To ascertain whether naringin-induced GDNF contributes to neuroprotection, we further investigated the effects of intranigral injection of neutralizing antibodies against GDNF in the MPP+ rat model of PD. Our observations demonstrate that naringin could increase the level of GDNF in DA neurons, contributing to neuroprotection in the MPP+ rat model of PD, with activation of mammalian target of rapamycin complex 1. Moreover, naringin could attenuate the level of tumor necrosis factor-α in microglia increased by MPP+-induced neurotoxicity in the substantia nigra. These results indicate that naringin could impart to DA neurons the important ability to produce GDNF as a therapeutic agent against PD with anti-inflammatory effects, suggesting that naringin is a beneficial natural product for the prevention of DA degeneration in the adult brain.

New drug treatments show neuroprotective effects in Alzheimer's and Parkinson's diseases.

Type 2 diabetes is a risk factor for Alzheimer's disease and Parkinson's disease. Insulin signaling in the brains of people with Alzheimer's disease or Parkinson's disease is impaired. Preclinical studies of growth factors showed impressive neuroprotective effects. In animal models of Alzheimer's disease and Parkinson's disease, insulin, glia-derived neurotrophic factor, or analogues of the incretin glucagon-like peptide-1 prevented neurodegenerative processes and improved neuronal and synaptic functionality in Alzheimer's disease and Parkinson's disease. On the basis of these promising findings, several clinical trials are ongoing with the first encouraging clinical results published. This gives hope for developing effective treatments for Alzheimer's disease and Parkinson's disease that are currently unavailable.

Promises of novel multi-target neuroprotective and neurorestorative drugs for Parkinson's disease

The cascade of neurotoxic events involved in neuronal degeneration suggests that it is naive to think mono-target drugs can induce disease modification by slowing the process of neurodegeneration in Parkinson's disease (PD). Employing the pharmacophore of rasagiline (N-propargyl-1-R-aminoindan), we have developed a series of novel multi-target neuroprotective drugs, including: (A) drugs [ladostigil, TV-3326 (N-propargyl-3R-aminoindan-5yl)-ethyl methylcarbamate)] with both cholinesterase-butyrylesterase (Ch-BuE) and brain-selective monamine oxidase-AB (MAO-AB) inhibitory activities and (B) iron chelator-radical scavenging drugs (M30) possessing brain-selective MAO-AB inhibitor activity and the neuroprotective-neurorescue propargylamine moiety of rasagiline. This was considered to be valid since brain MAO and iron increase in PD and aging, which could lead to oxidative stress-dependent neurodegeneration. The multi-target iron chelator, M30, has all the properties of ladostigil, but is not an acetylcholinesterase (CHE) inhibitor. However, M30 has both neuroprotective and neurorestorative activities for nigrostriatal dopamine neurons in post-lesion MPTP, lactacystin and 6-hydroxydopamine animal models of PD. The neurorestorative activity has been identified as being related to the ability of the drug to activate hypoxia-inducible factor (HIF) by inhibiting prolyl-4-hydroxylase. M30 regulates cell cycle arrest and induces the neurotrophins brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), erythropoietin (EPO), as well as glia-derived neurotrophic factor (GDNF). These unique multiple actions of M30 make it potentially useful as a disease modifying drug for the treatment of PD.