The Anti-Inflammatory Effects of Oral-Formulated Tacrolimus in Mice with Experimental Autoimmune Encephalomyelitis

Multiple sclerosis (MS) is a T-lymphocyte-mediated autoimmune disease that is characterized by inflammation in the central nervous system (CNS). Although many disease-modifying therapies (DMTs) are presumed effective in patients with MS, studies on the efficacy and safety of DMTs for preventing MS relapse are limited. Therefore, we tested the immunosuppressive anti-inflammatory effects of oral-formulated tacrolimus (FK506) on MS in a mouse model of experimental autoimmune encephalomyelitis (EAE). The mice were randomly divided into 3 experimental groups: an untreated EAE group, a low-dose tacrolimus-treated EAE group, and a high-dose tacrolimus-treated EAE group. After autoimmunization of the EAE mice with myelin oligodendrocyte glycoprotein, symptom severity scores, immunohistochemistry of the myelination of the spinal cord, and western blotting were used to evaluate the EAE mice. After the autoimmunization, the symptom scores of each EAE group significantly differed at times. The group treated with the larger tacrolimus dose had the lowest symptom scores. The tacrolimus-treated EAE groups exhibited less demyelination and inflammation and weak immunoreactivity for all of the immunization biomarkers. Our results revealed that oral-formulated tacrolimus inhibited the autoimmunization in MS pathogenesis by inactivating inflammatory cells.

Modulation of SOD1 Subcellular Localization by Transfection with Wild- or Mutant-type SOD1 in Primary Neuron and Astrocyte Cultures from ALS Mice

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder characterized by selective degeneration of motor neurons. Mutant superoxide dismutase 1 (SOD1) is often found as aggregates in the cytoplasm in motor neurons of various mouse models and familial ALS patients. The interplay between motor neurons and astrocytes is crucial for disease outcome, but the mechanisms underlying this phenomenon remain unknown. In this study, we investigated whether transient transfection with wild-type and mutant-type SOD1 may lead to amplification of mutant SOD1-mediated toxicity in cortical neurons and astrocytes derived from wild-type and mutant-type (human G93A-SOD1) mice. In transgenic mice expressing either wild- or mutant-type SOD1, we found that green fluorescent protein (GFP)-wtSOD1 was present in the cytoplasm and nuclei of wild-type cortical neurons and astrocytes, whereas GFP-mutant SOD1 was mainly cytoplasmic in wild- and mutant-type cortical neurons and astrocytes. These findings indicate that intracellular propagation of misfolding of GFP-wt or mtSOD1 are possible mediators of toxic processes involved in initiating mislocalization and aggregation. Here, we provide evidence that cytoplasmic aggregates induce apoptosis in G93A-SOD1 mouse cortical neurons and astrocytes and that the toxicity of mutant SOD1 in astrocytes is similar to the pathological effects of ALS on neurons in vitro. Collectively, our results indicate that mtSOD1 probably interacts with wtSOD1 via an unknown mechanism to produce augmented toxicity and may influence aggregate formation and apoptosis.

Neuroprotective Effect of Rapamycin (Autophagy Enhancer) in Transgenic SOD1-G93A Mice of Amyotrophic Lateral Sclerosis / 대한임상신경생리학회지

BACKGROUND: The autophagy is the major route for lysosomal degradation of misfolded protein aggregates and oxidative cell components. We hypothesized that rapamycin (autophagy enhancer) would prolong the survival of motor neuron and suppress the disease progression in amyotrophic lateral sclerosis (ALS). METHODS: A total of 24 transgenic mice harboring the human G93A mutated SOD1 gene were used. The clinical status involving rotarod test and survival, and biochemical study of ALS mice model were evaluated. RESULTS: The onset of symptoms was significantly delayed in the rapamycin administration group compared with the control group. However, after the clinical symptom developed, the rapamycin exacerbated the disease progression and shortened the survival of ALS mice model, and apoptosis signals were up-regulated compared with control group. CONCLUSIONS: Even though further detailed studies on the relevancy between autophagy and ALS will be needed, our results revealed that the rapamycin administration was not effective for being novel promising therapeutic strategy in ALS transgenic mice and exacerbated the apoptosis.

Immunohistochemical Study on the TfBP Expression in the Embryonic Chick Cerebellum / 대한해부학회지

We have previously demonstrated that transferrin binding protein (TfBP) is a reliable marker for mature oligoden-drocytes (OLGs) in the avian central nervous system (CNS). Unlike mammalian CNS in which OLGs are generated largely postnatally, avian OLGs are differentiated during embryonic development of CNS. In this study, several aspects of TfBP(+/-) OLG development were immunohistochemically examined in the embryonic chick cerebellum : (1) change in shapes of immature cells with respect to time and to location within the cerebellum, (2) possible sites of origin, and (3) pathways of precursor cell migration. Our results indicate that TfBP expression gradually increases and extends from the deep portion of the white matter to gray matter with proportion to progress of cerebellar development. A few TfBP? cells were first observed in the deep portion of the cerebellum at E9. At E13, TfBP(+/-) cells were distributed evenly within the white matter. At E17, many TfBP(+/-) OLGs were located at granular layer and at the near place of Purkinje cell layer. At E20, a large number of TfBP cells appeared at the granular layer with a few in the molecular layer. Our data demonstrated distinct patterns of morphology and location of TfBP(+/-) OLGs in the cerebellum during development and suggest a role of TfBP in OLG development.

The Alteration of Avian Retinal Microglia Induced by Optic Nerve Transection / 대한해부학회지

Retina, a part of CNS, has served valuable and accessible tissue for elucidating the cellular properties of neurons and glia due to its similarity to brain. Unlike mammalian counterpart, avian retina is devoid of vessels and astrocytes. However little is known about glial reaction to neuronal injuries in this species. Therefore, this study was performed to investigate the microglial responses in the quail retina following neuronal injuries. The retinae from normal and optic nerve transected adult quails were studied immunohistochemically with anti-QH1, a marker known to be specific for microglia. In the normal retina, QH1-labeled microglial cells displayed typical feature of ramified (resting) form and were localized mainly in the inner plexiform layer. After optic nerve transection (ONT) morphology of microglial cells changed from the ramified to the amoeboid form. This feature of microglial cells maintained throughout the post operational periods until 28 days after ONT. Particularly, at 14 and 21 days after ONT amoeboid microglia displayed cell bodies with stout and bushy processes, suggesting active phagocytosis. The distribution pattern of microglia also changed in accord to ganglion cell degeneration: they gradually moved to layers of ganglion cells and optic nerve fibers where ganglion cell bodies and axons were under degeneration. This change of microglial distribution was most prominent at 14 days of ONT. The result of this study is generally consistent with that reported in mammalian counterpart and this similarity between the avascular avian retina and the vascularized mammalian counterpart suggests that processes of microglial activation, such as migration and phagocytosis, can occur in the vessel-free CNS tissue.

Carbonic anhydrase II immunostaining in the cerebellum of postnatal mice / 대한해부학회지

The carbonic anhydrase II (CA-II) is specifically expressed in oligodendrocytes, the cells responsible for myelination in the central nervous system. However no direct evidence on relationship between myelin formation and CA-II immunoreactivity has been described. The aims of these studies are to investigate the relationship between CA-II and myelination during cerebellar development of mouse. Myelin staining was found on postnatal (P) 14, and its intensity increased in proportion to developmental age. CA-II positive oligodendrocytes were observed in the white matter of cerebellum on P 14 day. CA-II positive oligoden-drocytes also occured in the granular layer and Purkinje cell layers in the later stage of dvelopment. The parallel development in the CA-II expression and myelination during development suggests that CA-II in oligoendrocyte play a role to myelination.