Dong Liang Ma

Duke-NUS Graduate Medical School Singapore, Tumasik, Singapore

Are you Dong Liang Ma?

Claim your profile

Publications (6)17.35 Total impact

  • Xin Li Xiao, Dong Liang Ma, Jing Wu, Feng Ru Tang
    [Show abstract] [Hide abstract]
    ABSTRACT: Metabotropic glutamate receptor 5 (mGluR5) is involved in neural stem cell self-renewal, proliferation, differentiation and survival. In this study, we aimed to further determine the role of mGluR5 in the development of hippocampus using mGluR5 deficit (mGluR5(-/-)) and wild type (mGluR5(+/+)) mice at different developmental ages. We showed that the number of BrdU, NeuroD and DCX immunopositive cells was reduced significantly in mGluR5(-/-) than in mGluR5(+/+) mice from postnatal 7 days (P7) to P28, but not at P60. The length and intensity of DCX immunopositive apical dendrites in the dentate gyrus of mGluR5(-/-) mice were much shorter and lower than in mGluR5(+/+) mice respectively at P14, P21 and P28. NeuN immunostaining indicated an accelerated maturation of hippocampal neurons in mGluR5(-/-) mice. When mGluR5(+/+) mice were treated with 2-methyl-6-(phenylethynyl) pyridine (MPEP), a selective antagonist of mGluR5, decreased proliferation of progenitor cells was observed in the hippocampus at early postnatal developmental stages. At P14, there were more BrdU(+) cells in the stratum granulosum and subgranular layer of the dentate gyrus in mGluR5(+/+) than in mGluR5(-/-) mice, but the percentage of BrdU(+)+NeuroD(+)/BrdU(+) in the dentate gyrus did not change significantly between the two genotypes of mice. Western Blot study suggested that programmed neuronal death was p53-dependent apoptosis in the developmental hippocampus in mGluR5(+/+) mice.
    Brain research 11/2012; 1493. DOI:10.1016/j.brainres.2012.11.015 · 2.83 Impact Factor
  • Jing Wu, Dong Liang Ma, Eng Ang Ling, Feng Ru Tang
    [Show abstract] [Hide abstract]
    ABSTRACT: We investigated the cellular localization and progressive changes of corticotropin releasing factor (CRF) in the mouse hippocampus, during and after pilocarpine induced status epilepticus (PISE) and subsequent epileptogenesis. We found that CRF gene expression was up-regulated significantly at 2h during and 1d after PISE in comparison to control mice. Immunohistochemical analysis showed that the number of CRF and Fos immunoreactive cells was increased significantly in the strata oriens and pyramidale of CA1 area and in the stratum pyramidale of CA3 area at 2h during and 1d after PISE. CRF was induced in calbindin (CB) or calretinin (CR) immunoreactive interneurons in stratum oriens at 2h during PISE. It suggests that induced CRF may be related to the over excitation of hippocampal neurons and occurrence of status epilepticus. It may also cause excitoneurotoxicity and delayed loss of CA3 and CA1 pyramidal neurons, leading to the onset of epilepsy.
    Neuroscience Letters 03/2012; 512(2):83-8. DOI:10.1016/j.neulet.2012.01.057 · 2.06 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The goal of this study was to examine the morpho-physiologic changes in the dorsal subiculum network in the mouse model of temporal lobe epilepsy using extracellular recording, juxtacellular and immunofluorescence double labeling, and anterograde tracing methods. A significant loss of total dorsal subicular neurons, particularly calbindin, parvalbumin (PV) and immunopositive interneurons, was found at 2 months after pilocarpine-induced status epilepticus (SE). However, the sprouting of axons from lateral entorhinal cortex (LEnt) was observed to contact with surviving subicular neurons. These neurons had two predominant discharge patterns: bursting and fast irregular discharges. The bursting neurons were mainly pyramidal cells, and their dendritic spine density and bursting discharge rates were increased significantly in SE mice compared with the control group. Fast irregular discharge neurons were PV-immunopositive interneurons and had less dendritic spines in SE mice when compared with the control mice. When LEnt was stimulated, bursting and fast irregular discharge neurons had much shorter latency and stronger excitatory response in SE mice compared with the control group. Our results illustrate that morpho-physiologic changes in the dorsal subiculum could be part of a multilevel pathologic network that occurs simultaneously in many brain areas to contribute to the generation of epileptiform activity.
    Brain Pathology 03/2009; 20(1):80-95. DOI:10.1111/j.1750-3639.2009.00243.x · 4.35 Impact Factor
  • Dong Liang Ma, Yong Cheng Tang, Feng Ru Tang
    [Show abstract] [Hide abstract]
    ABSTRACT: With the mouse pilocarpine model of temporal lobe epilepsy (TLE), we showed a progressive loss of both principal cells and calbindin (CB)-, calretinin (CR)-, and parvalbumin (PV)-immunopositive interneurons in layers II-III of lateral entorhinal cortex (LEnt) from 2 months to 1 year after pilocarpine-induced status epilepticus (PISE). In the efferent pathway of LEnt, more Phaseolus vulgaris leucoagglutinin (PHA-L)-labelled en passant and terminal boutons with larger diameters were shown in the hippocampus and subiculum; in the prefrontal, piriform, and perirhinal cortices; and in the amygdaloid complex in experimental mice at the two time points compared with the control after iontophoretical injection of an anterograde tracer PHA-L into the LEnt. Furthermore, the numbers of CB- or CR-immunopositive neurons contacted by PHA-L-labelled en passant and terminal boutons decreased in most of these areas at 2 months or 1 year after PISE. In the afferent pathway of LEnt, the numbers of retrogradely labelled neurons were reduced significantly in the ipsilateral piriform cortex and endopiriform nucleus at 2 months and 1 year and in the reuniens thalamic nucleus only at 1 year after injection of a retrograde tracer cholera toxin B subunit (CTB) into the LEnt. The percentages of the number of CTB and CB or CR double-labelled neurons of all the retrogradely labelled neurons were also decreased in the reunions thalamic nucleus at 1 year after PISE. It is concluded that both cytoarchitectonic change and reorganization of afferent and efferent pathways in LEnt may be involved in the occurrence of TLE.
    Journal of Neuroscience Research 05/2008; 86(6):1324-42. DOI:10.1002/jnr.21583 · 2.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the present in situ hybridization and immunocytochemical studies in the mouse central nervous system (CNS), a strong expression of spastin mRNA and protein was found in Purkinje cells and dentate nucleus in the cerebellum, in hippocampal principal cells and hilar neurons, in amygdala, substantia nigra, striatum, in the motor nuclei of the cranial nerves and in different layers of the cerebral cortex except piriform and entorhinal cortices where only neurons in layer II were strongly stained. Spastin protein and mRNA were weakly expressed in most of the thalamic nuclei. In selected human brain regions such as the cerebral cortex, cerebellum, hippocampus, amygdala, substania nigra and striatum, similar results were obtained. Electron microscopy showed spastin immunopositive staining in the cytoplasma, dendrites, axon terminals and nucleus. In the mouse pilocarpine model of status epilepticus and subsequent temporal lobe epilepsy, spastin expression disappeared in hilar neurons as early as at 2h during pilocarpine induced status epilepticus, and never recovered. At 7 days and 2 months after pilocarpine induced status epilepticus, spastin expression was down-regulated in granule cells in the dentate gyrus, but induced expression was found in reactive astrocytes. The demonstration of widespread distribution of spastin in functionally different brain regions in the present study may provide neuroanatomical basis to explain why different neurological, psychological disorders and cognitive impairment occur in patients with spastin mutation. Down-regulation or loss of spastin expression in hilar neurons may be related to their degeneration and may therefore initiate epileptogenetic events, leading to temporal lobe epilepsy.
    Neurochemistry International 01/2007; 49(7):651-64. DOI:10.1016/j.neuint.2006.05.008 · 2.65 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We showed that when CA3 pyramidal neurons in the caudal 80% of the dorsal hippocampus had almost disappeared completely, the efferent pathway of CA3 was rarely detectable. We used the mouse pilocarpine model of temporal lobe epilepsy (TLE), and injected iontophoretically the anterograde tracer phaseolus vulgaris leucoagglutinin (PHA-L) into gliotic CA3, medial septum and the nucleus of diagonal band of Broca, median raphe, and lateral supramammillary nuclei, or the retrograde tracer cholera toxin B subunit (CTB) into gliotic CA3 area of hippocampus. In the afferent pathway, the number of neurons projecting to CA3 from medial septum and the nucleus of diagonal band of Broca, median raphe, and lateral supramammillary nuclei increased significantly. In the hippocampus, where CA3 pyramidal neurons were partially lost, calbindin, calretinin, parvalbumin immunopositive back-projection neurons from CA1-CA3 area were observed. Sprouting of Schaffer collaterals with increased number of large boutons in both sides of CA1 area, particularly in the stratum pyramidale, was found. When CA3 pyramidal neurons in caudal 80% of the dorsal hippocampus have almost disappeared completely, surviving CA3 neurons in the rostral 20% of the dorsal hippocampus may play an important role in transmitting hyperactivity of granule cells to surviving CA1 neurons or to dorsal part of the lateral septum. We concluded that reorganization of CA3 area with its downstream or upstream nuclei may be involved in the occurrence of epilepsy.
    Journal of Neuroscience Research 02/2006; 83(2):318-31. DOI:10.1002/jnr.20731 · 2.73 Impact Factor