Chunmei Ma

Human mesenchymal stem cell transplantation protects against cerebral ischemic injury and upregulates interleukin-10 expression in Macacafascicularis

Mesenchymal stem cell (MSC) transplantation has been reported to improve neurologic function after ischemic injury. However, the detailed mechanisms by which MSCs promote functional recovery are not fully understood. Interleukin-10 (IL-10) is a well-known anti-inflammatory cytokine with neuroprotective effects with respect to brain injury. In this study, a non-human primate ischemia model was used to test the hypothesis that transplanted human bone-marrow-derived MSCs (hBMSCs) exert a neuroprotective effects on cerebral ischemia and upregulate IL-10 expression. We also assessed neuronal apoptosis and astroglial activity in the area around the ischemic lesion and proliferating cells in the subventricular zone (SVZ). Results showed that hBMSC transplantation in ischemic tissues improved the neurological functions and induced an increase in IL-10 expression. In addition, neuronal apoptosis and astroglial activity in the peri-ischemic area decreased, and the number of proliferating cells in the SVZ increased. These results provide a novel therapeutic strategy for improving neurologic function after cerebral ischemia.

Transgenic expression of human P-selectin glycoprotein ligand-1 is not sufficient for enterovirus 71 infection in mice

Human PSGL-1 is a receptor for EV71 that facilitates EV71 entry and replication in mouse cells. We have evaluated the role of human PSGL-1 in EV71 infection in vivo using a transgenic mouse line. Expression of human PSGL-1 failed to enhance infectivity of clinical EV71 strains in mice; however, it promoted replication and symptom severity at an earlier stage in mice upon infection with a mouse-adapted EV71 strain. We therefore conclude that human PSGL-1 alone is not sufficient to modulate infection with the clinical EV71 strains of genotype C4 in mice.

Pathological lesions and viral localization of Influenza A (H5N1) virus in experimentally infected Chinese rhesus macaques: implications for pathogenesis and viral transmission

Chinese rhesus macaques infected with influenza virus A/Tiger/Harbin/01/2002 (H5N1) developed acute interstitial pneumonia with diffuse alveolar damage. The results of virus isolation, reverse transcriptase polymerase chain reaction, immunohistochemistry, and in situ hybridization showed that the lung was the major target organ of the H5N1 virus infection. No virus was detected in the extrapulmonary organs. The results of immunohistochemistry and in situ hybridization also showed that pneumocytes and macrophages of the lower airway, not the ciliary epithelium of the trachea and bronchi, were the chief target cells in the lung tissue of the infected Chinese rhesus macaque. Our data indicate that the Chinese rhesus macaque is suitable as a new primate model for H5N1 virus research, especially for the study of H5N1 virus transmission. The predilection of the H5N1 virus to infect the lower airway suggests that the failure of the virus to attach to the ciliary epithelium of the trachea and bronchi may be a limiting factor in human-to-human transmissibility of the H5N1 virus.

G-protein-coupled receptor kinase 5, overexpressed in the α-synuclein up-regulation model of Parkinson's disease, regulates bcl-2 expression

G protein-coupled receptor kinase 5 (GRK5) has been reported to accumulate in Lewy bodies (LBs), a histological hallmark of Parkinsons disease. Recent findings propose that GRK5 might function in Parkinsons disease via phosphorylation of alpha-synuclein, a major component of LBs. In this study, the changes of the expression levels of GRK5 and its possible effects in Parkinsons disease were evaluated in cell lines and transgenic mice model of alpha-synuclein overexpression. Both the expression levels of cytoplasmic and nuclear distributed GRK5 were induced an increase via alpha-synuclein overexpression in vivo and in vitro. The observations that the levels of alpha-synuclein phosphorylated at Ser-129 (pS129-alpha-synuclein) remain unchanged despite the downregulation of GRK5 by short hairpin ribonucleic acid (shRNA) transfection suggest that GRK5 is not the sole kinase involved in phosphorylating alpha-synuclein in Parkinsons disease. In addition, the findings that nuclear accumulation of GRK5 inhibits bcl-2 transcription and expression, at least in part by enhancing histone deacetylase (HDAC) activity, show an unexpected role for nuclear GRK5 in the regulation of an apoptosis-related gene. The present study suggests that GRK5 may be extensively involved in the mechanism of Parkinsons disease.

Long-term naringin consumption reverses a glucose uptake defect and improves cognitive deficits in a mouse model of Alzheimer's disease

Naringin, a bioflavonoid, has been reported to have potent neuro-protective effects, but its preventive effects on amyloid-β (Aβ) induced, Alzheimers disease (AD) related, cognitive impairment, and the underlying mechanisms of these effects have not been well characterised. Three-month-old APPswe/PSΔE9 transgenic mice were randomly assigned to a vehicle group, two naringin (either 50 or 100 mg/kg/day) groups, or an Aricept (2 mg/kg/day) group. After 16 weeks of treatment, we observed beneficial effects of naringin (100 mg/kg/day), including lessening learning and memory deficits, improving locomotor activity, reducing scattered senile plaques, and ameliorating disturbances in brain energy metabolism. Furthermore, GSK-3β phosphorylation significantly increased in the naringin-treated (100 mg/kg/day) group. These findings suggest that a reduction in plaque burden and an increase in glucose uptake through the inhibition of GSK-3β activity may be one of the mechanisms by which naringin improves cognitive functioning in the APPswe/ PSΔE9 transgenic mouse model of Alzheimers disease.

Genomic Polymorphism of the Pandemic A (H1N1) Influenza Viruses Correlates with Viral Replication, Virulence, and Pathogenicity In Vitro and In Vivo

The novel pandemic A (H1N1) virus was first identified in Mexico in April 2009 and quickly spread worldwide. Like all influenzas, the H1N1 strain-specific properties of replication, virulence, and pathogenicity are a result of the particular genomic sequence and concerted expression of multiple genes. Thus, specific mutations may support increased virulence and may be useful as biomarkers of potential threat to human health. We performed comparative genomic analysis of ten strains of the 2009 pandemic A (H1N1) influenza viruses to determine whether genotypes associated with clinical phenotypes, which ranged from mild to severe illness and up to lethal. Virus replication capacity was tested for each strain in vitro using cultured epithelial cells, while virulence and pathogenicity were investigated in vivo using the BALB/c mouse model. The results indicated that A/Sichuan/1/2009 strain had significantly higher replication ability and virulence than the other strains, and five unique non-synonymous mutations were identified in important gene-encoding sequences. These mutations led to amino acid substitutions in HA (L32I), PA (A343T), PB1 (K353R and T566A), and PB2 (T471M), and may be critical molecular determinants for replication, virulence, and pathogenicity. Our results suggested that the replication capacity in vitro and virulence in vivo of the 2009 pandemic A (H1N1) viruses were not associated with the clinical phenotypes. This study offers new insights into the transmission and evolution of the 2009 pandemic A (H1N1) virus.

The effect of PN-1, a Traditional Chinese Prescription, on the Learning and Memory in a Transgenic Mouse Model of Alzheimer’s Disease

Traditional Chinese Medicine (TCM) is a complete medical system that has been practiced for more than 3000 years. Prescription number 1 (PN-1) consists of several Chinese medicines and is designed according to TCM theories to treat patients with neuropsychiatric disorders. The evidence of clinical practice suggests the benefit effects of PN-1 on cognitive deficits of dementia patients. We try to prove and explain this by using contemporary methodology and transgenic animal models of Alzheimers disease (AD). The behavioral studies were developed to evaluate the memory of transgenic animals after intragastric administration of PN-1 for 3 months. Amyloid beta-protein (Aβ) neuropathology was quantified using immunohistochemistry and ELISA. The western blotting was used to detect the levels of plasticity associated proteins. The safety of PN-1 on mice was also assessed through multiple parameters. Results showed that PN-1 could effectively relieve learning and memory impairment of transgenic animals. Possible mechanisms showed that PN-1 could significantly reduce plaque burden and Aβ levels and boost synaptic plasticity. Our observations showed that PN-1 could improve learning and memory ability through multiple mechanisms without detectable side effects on mice. We propose that PN-1 is a promising alternative treatment for AD in the future.

Regional and cell-type specific distribution of HDAC2 in the adult mouse brain.

The effects of epigenetics on brain functions are not completely understood, but histone deacetylases (HDACs) are known to affect brain function and dysfunction by mediating the acetylation status of target proteins, thereby affecting gene expression. The current study used immunochemistry to illuminate the regional distribution of one member of the HDAC family, HDAC2, in the C57BL/6J mouse brain. Our data show that HDAC2 is ubiquitously expressed throughout the mouse brain and is localized primarily within the cell nucleus. Using double-immunofluorescence, we demonstrated HDAC2 expression in neuronal cells, including cholinergic, serotonergic and catecholaminergic neurons, as well as postsynaptic glutamatergic and GABAergic neurons. HDAC2 was also observed in oligodendrocytes, but not in astrocytes or microglia. These detailed immunological studies illuminate the distribution of HDAC2 throughout the mouse brain and will facilitate investigation of the roles of HDAC2 in brain function and neurological disorders.

Migration and differentiation of human mesenchymal stem cells in the normal rat brain

Abstract Objectives: Transplanted mesenchymal stem cells migrate toward brain lesions and differentiate into neurons, glial cells, and neural stem cells in diseased or injured animal models. The migratory routes and differentiation patterns of mesenchymal stem cells in normal rats are, however, unknown. Here, labelled human mesenchymal stem cells (or saline) were transplanted into the striatum of adult rats to observe their migration and differentiation. Methods: Labelled human mesenchymal stem cells were transplanted into the right striatum of adults rats (n = 24). Brain sections were examined for migratory routes of labelled human mesenchymal stem cells by immunohistochemistry method, fluorescence microscope and laser scanning confocal microscopy observation, and Prussian blue staining. Moreover, the differentiation of human mesenchymal stem cells was detected by double immunohistochemistry. Results: After 3 days, most human mesenchymal stem cells resided around the injection sites. Human mesenchymal stem cells were found in or around the corpus callosum and the subependymal layer after 7 days. A great number of human mesenchymal stem cells were detected throughout the brain on both ipsilateral and contralateral sides after 14 days. A high concentration of donor cells persisted in the corpus callosum, the external capsule and the subventricular zone. In addition, the incorporated human mesenchymal stem cells were neuronal nuclei- and glial fibrillary acidic protein-positive. Conclusion: Human mesenchymal stem cells migrate throughout the brain mainly along with the axis of corpus callosum external capsule and the subependymal layer, and differentiate into neurons and astrocytes rather than neural stem cells.

Cardiotrophin-1 (CTF1) ameliorates glucose-uptake defects and improves memory and learning deficits in a transgenic mouse model of Alzheimer's disease

Cardiotrophin-1 (CTF1) has been reported to act as a trophic factor for a few neurons, such as sensory, cholinergic, dopaminergic, motor and cortical neurons. Studies have indicated that CTF1 delays degenerative disease progression in motor neuron disease. However, little is known about the effects of CTF1 on degenerative disease in the brain. We have shown that expression of CTF1 is strongly down-regulated in the brain of the APPswe/PS1dE9 transgenic mouse model of Alzheimers disease (AD). Transgenic mice with brain tissue-specific CTF1 expression alone or in combination with APPswe/PS1dE9 transgenic mice were produced to study the effects of CTF1 on AD. CTF1 expressing APPswe/PS1dE9 transgenic mice exhibited improvements in learning and memory, less severe abnormalities in locomotor activity, reduced scattered senile plaques and ameliorated disturbances of brain energy metabolism compared to APPswe/PS1dE9 transgenic mice. Furthermore, CTF1 inhibited the activity of glycogen synthase kinase-3β (GSK-3β) in SH-SY5Y cell line and in the brain tissues of APPswe/PS1dE9 transgenic mice. The transgenic expression of CTF1 compensated for the loss of CTF1 expression and brought about a marked improvement on cognitive functioning in the APPswe/PS1dE9 transgenic mouse model of Alzheimers disease, suggesting that the inhibition of GSK-3β activity might play an important role.