Jinsha Huang

VEGF-expressing human umbilical cord mesenchymal stem cells, an improved therapy strategy for Parkinson’s disease

The umbilical cord provides a rich source of primitive mesenchymal stem cells (human umbilical cord mesenchymal stem cells (HUMSCs)), which have the potential for transplantation-based treatments of Parkinsons Disease (PD). Our pervious study indicated that adenovirus-associated virus-mediated intrastriatal delivery of human vascular endothelial growth factor 165 (VEGF 165) conferred molecular protection to the dopaminergic system. As both VEGF and HUMSCs displayed limited neuroprotection, in this study we investigated whether HUMSCs combined with VEGF expression could offer enhanced neuroprotection. HUMSCs were modified by adenovirus-mediated VEGF gene transfer, and subsequently transplanted into rotenone-lesioned striatum of hemiparkinsonian rats. As a result, HUMSCs differentiated into dopaminergic neuron-like cells on the basis of neuron-specific enolase (NSE) (neuronal marker), glial fibrillary acidic protein (GFAP) (astrocyte marker), nestin (neural stem cell marker) and tyrosine hydroxylase (TH) (dopaminergic marker) expression. Further, VEGF expression significantly enhanced the dopaminergic differentiation of HUMSCs in vivo. HUMSC transplantation ameliorated apomorphine-evoked rotations and reduced the loss of dopaminergic neurons in the lesioned substantia nigra (SNc), which was enhanced significantly by VEGF expression in HUMSCs. These findings present the suitability of HUMSC as a vector for gene therapy and suggest that stem cell engineering with VEGF may improve the transplantation strategy for the treatment of PD.

Mitochondrial complex I inhibitor rotenone-induced toxicity and its potential mechanisms in Parkinson’s disease models

The etiology of Parkinson’s disease (PD) is attributed to both environmental and genetic factors. The development of PD reportedly involves mitochondrial impairment, oxidative stress, α-synuclein aggregation, dysfunctional protein degradation, glutamate toxicity, calcium overloading, inflammation and loss of neurotrophic factors. Based on a link between mitochondrial dysfunction and pesticide exposure, many laboratories, including ours, have recently developed parkinsonian models by utilization of rotenone, a well-known mitochondrial complex I inhibitor. Rotenone models for PD appear to mimic most clinical features of idiopathic PD and recapitulate the slow and progressive loss of dopaminergic (DA) neurons and the Lewy body formation in the nigral-striatal system. Notably, potential human parkinsonian pathogenetic and pathophysiological mechanisms have been revealed through these models. In this review, we summarized various rotenone-based models for PD and discussed the implied etiology of and treatment for PD

Potential autophagy enhancers attenuate rotenone-induced toxicity in SH-SY5Y.

Recent studies have shown that autophagy upregulation may be a tractable therapeutic intervention for clearing the disease-causing proteins, including α-synuclein, ubiquitin, and other misfolded or aggregated proteins in Parkinsons disease (PD). In this study, we explored a novel pharmacotherapeutic approach to treating PD by utilizing potential autophagy enhancers valproic acid (VPA) and carbamazepine (CBZ). Pretreatment with VPA (3 mM) and CBZ (50 μM) along with positive control rapamycin (Rap, 0.2 μM) or lithium (LiCl, 10 mM) significantly enhanced cell viability, decreased rotenone-induced nuclear fragmentation and apoptosis, ameliorated the decrease in mitochondrial membrane potential, reduced reactive oxygen species generation in the human neuroblastoma SH-SY5Y cells. Specifically, the numbers of lysosomes and autophagic vacuolar organelles were increased and the microtubule-associated protein 1 light chain 3-II (LC3-II) expression was up-regulated by VPA, CBZ, Rap, and LiCl (53%, 31%, 72%, and 63%), suggesting that these agents activated autophagic pathways. Moreover, pretreatment with the autophagy inhibitor chloroquine (Chl, 10 μM) remarkably strengthened rotenone toxicity in these cells. Our results suggest that VPA and CBZ, the most commonly used anti-epilepsy and mood-stabilizing medications with low-risk and easy administration might be potential therapeutics for PD.

Stereotaxical Infusion of Rotenone: A Reliable Rodent Model for Parkinson's Disease

A clinically-related animal model of Parkinsons disease (PD) may enable the elucidation of the etiology of the disease and assist the development of medications. However, none of the current neurotoxin-based models recapitulates the main clinical features of the disease or the pathological hallmarks, such as dopamine (DA) neuron specificity of degeneration and Lewy body formation, which limits the use of these models in PD research. To overcome these limitations, we developed a rat model by stereotaxically (ST) infusing small doses of the mitochondrial complex-I inhibitor, rotenone, into two brain sites: the right ventral tegmental area and the substantia nigra. Four weeks after ST rotenone administration, tyrosine hydroxylase (TH) immunoreactivity in the infusion side decreased by 43.7%, in contrast to a 75.8% decrease observed in rats treated systemically with rotenone (SYS). The rotenone infusion also reduced the DA content, the glutathione and superoxide dismutase activities, and induced alpha-synuclein expression, when compared to the contralateral side. This ST model displays neither peripheral toxicity or mortality and has a high success rate. This rotenone-based ST model thus recapitulates the slow and specific loss of DA neurons and better mimics the clinical features of idiopathic PD, representing a reliable and more clinically-related model for PD research.

Morin exerts neuroprotective actions in Parkinson disease models in vitro and in vivo.

AbstractAim:To investigate the neuroprotective effects of morin on 1-methyl-4-phenylpyridinium ion (MPP+)-induced apoptosis in neuronal differentiated PC12 cells as well as in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson disease (PD).Methods:PC12 cells were challenged with MPP+ in the presence or absence of morin. Cell viability was determined using MTT assay. Cell apoptosis was measured using flow cytometry. Generation of reactive oxygen species (ROS) was assayed using fluorescence assay. In an MPTP mouse model of PD, behavioral deficits, striatal dopamine content, and number of dopaminergic neurons were measured.Results:MPP+ induced apoptosis and ROS formation in PC12 cells. Concomitant treatment with morin (5-50 μmol/L) significantly attenuated the loss of cell viability and apoptosis when compared with MPP+ treatment alone. Morin also attenuated ROS formation induced by MPP+. MPTP induced permanent behavioral deficits and nigrostriatal lesions in mice. When administered prior to MPTP, morin (20 to 100 mg/kg) attenuated behavioral deficits, dopaminergic neuronal death and striatal dopamine depletion in the MPTP mouse model.Conclusion:The findings suggest that morin has neuroprotective actions both in vitro and in vivo, and may provide a novel therapeutic agent for the treatment of PD and other neurodegenerative diseases.

Dl-3-n-butylphthalide, a natural antioxidant, protects dopamine neurons in rotenone models for Parkinson's disease

In the absence of a cure for Parkinsons disease, development of preventive medications for this devastating disease is particularly encouraged. Dl-3-n-butylphthalide (NBP), an established natural antioxidant for clinical stroke treatment in China, can reportedly reduce beta-amyloid-induced neuronal toxicity in cultured neuronal cells, and attenuate neurodegenerative changes in aged rats. However, whether or not NBP confers neuroprotection in parkinsonian models is still unknown. In this study, we investigated the effects of NBP in rotenone models for Parkinsons diseases. In a cellular model, pretreatment with NBP enhanced cell viability by decreasing nuclear fragmentation, retaining mitochondrial membrane potential, and preventing reactive oxygen species (ROS) from generation. In a rodent model, 2-week treatment with NBP was able to ameliorate apomorphine-evoked rotations by 48% and rescue dopaminergic (DA) neurons by 30% and striatal DA terminal by 49%. Furthermore, NBP upregulated the vesicular monoamine transporter 2 gene expression in vitro and in vivo. Together, NBP protects DA neurons likely by reducing oxidative stress, offering an alternative neuroprotective medication for Parkinsons disease.

Involvement of glyceraldehyde-3-phosphate dehydrogenase in rotenone-induced cell apoptosis: relevance to protein misfolding and aggregation.

The hallmarks of Parkinsons disease (PD) are the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the presence of intracellular inclusion bodies in surviving neurons. Although the specific etiology and pathogenesis of sporadic PD remains unknown, neuronal death was proven to be associated with mitochondrial dysfunction and protein misfolding. However, molecular links between mitochondrial dysfunction and protein misfolding remains obscure. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a classical glycolytic enzyme, is responsible for carbohydrate metabolism under normal circumstances. When translocated to the nucleus, GAPDH promotes neuron apoptosis in several neurodegenerative disorders. But it seems that GAPDH translocation is not the sole mechanism responsible for neuronal apoptosis. We found that rotenone, a common mitochondrial complex I inhibitor used to produce experimental parkinsonism, cannot only induce GAPDH translocation but also trigger intermolecular disulfide bonding and result in the formation of intracytoplasmic aggregates of GAPDH. This suggests a link between mitochondrial dysfunction and protein misfolding, and sheds light on the pathophysiology of Lewy body formation in Parkinsons disease.

The role of autophagy in Parkinson's disease: rotenone-based modeling

BackgroundAutophagy-mediated self-digestion of cytoplasmic inclusions may be protective against neurodegenerative diseases such as Parkinson’s disease (PD). However, excessive autophagic activation evokes autophagic programmed cell death.MethodsIn this study, we aimed at exploring the role of autophagy in the pathogenesis of rotenone-induced cellular and animal models for PD.ResultsReactive oxygen species over-generation, mitochondrial membrane potential reduction or apoptosis rate elevation occurred in a dose-dependent fashion in rotenone-treated human neuroblastoma cell line SH-SY5Y. The time- and dose-dependent increases in autophagic marker microtubule-associated protein1 light chain 3 (LC3) expression and decreases in autophagic adaptor protein P62 were observed in this cellular model. LC3-positive autophagic vacuoles were colocalized with alpha-synuclein-overexpressed aggregations. Moreover, the number of autophagic vacuoles was increased in rotenone-based PD models in vitro and in vivo.ConclusionsThese data, along with our previous finding showing rotenone-induced toxicity was prevented by the autophagy enhancers and was aggravated by the autophagy inhibitors in SH-SY5Y, suggest that autophagy contributes to the pathogenesis of PD, attenuates the rotenone toxicity and possibly represents a new subcellular target for treating PD.

Edaravone guards dopamine neurons in a rotenone model for Parkinson's disease.

3-methyl-1-phenyl-2-pyrazolin-5-one (edaravone), an effective free radical scavenger, provides neuroprotection in stroke models and patients. In this study, we investigated its neuroprotective effects in a chronic rotenone rat model for Parkinsons disease. Here we showed that a five-week treatment with edaravone abolished rotenones activity to induce catalepsy, damage mitochondria and degenerate dopamine neurons in the midbrain of rotenone-treated rats. This abolishment was attributable at least partly to edaravones inhibition of rotenone-induced reactive oxygen species production or apoptotic promoter Bax expression and its up-regulation of the vesicular monoamine transporter 2 (VMAT2) expression. Collectively, edaravone may provide novel clinical therapeutics for PD.

Exosomes and Their Therapeutic Potentials of Stem Cells

Exosomes, a group of vesicles originating from the multivesicular bodies (MVBs), are released into the extracellular space when MVBs fuse with the plasma membrane. Numerous studies indicate that exosomes play important roles in cell-to-cell communication, and exosomes from specific cell types and conditions display multiple functions such as exerting positive effects on regeneration in many tissues. It is widely accepted that the therapeutic potential of stem cells may be mediated largely by the paracrine factors, so harnessing the paracrine effects of stem and progenitor cells without affecting these living, replicating, and potentially pluripotent cell populations is an advantage in terms of safety and complexity. Ascending evidence indicated that exosomes might be the main components of paracrine factors; thus, understanding the role of exosomes in each subtype of stem cells is far-reaching. In this review, we discuss the functions of exosomes from different types of stem cells and emphasize the therapeutic potentials of exosomes, providing an alternative way of developing strategies to cure diseases.