Md. Nabiul Islam

Interaction of ataxin-3 with huntingtin-associated protein 1 through Josephin domain.

Huntingtin-associated protein 1 (HAP1) is an essential component of the stigmoid body (STB) and known as a possible neuroprotective interactor with causative proteins for Huntingtons disease, spinal and bulbar muscular atrophy, spinocerebellar ataxia type 17 (SCA17), and Joubert syndrome. To clarify what other causative molecules HAP1/STB could interact with, we cloned normal causative genes for several neural disorders from human brain RNA library and evaluated their subcellular interaction with HAP1/STB by immunocytochemistry and immunoprecipitation after cotransfection into Neuro2a cells. The results clearly showed that HAP1/STB interacts with the normal ataxin-3 through Josephin domain and polyglutamine-expanded mutants derived from SCA3 as well. The findings suggest that HAP1/STB could modify the physiological function of normal ataxin-3 and pathogenesis of SCA3 attributable to the mutant ataxin-3.

Intracellular colocalization of HAP1/STBs with steroid hormone receptors and its enhancement by a proteasome inhibitor

The stigmoid body (STB) is a cytoplasmic inclusion containing huntingtin-associated protein 1 (HAP1), and HAP1/STB formation is induced by transfection of the HAP1 gene into cultured cells. In the present study, we examined the intracellular colocalization of HAP1/STBs with steroid hormone receptors (SHRs), including the androgen receptor (AR), estrogen receptor, glucocorticoid receptor (GR), and mineralocorticoid receptor, in COS-7 cells cotransfected with HAP1 and each receptor. We found that C-terminal ligand-binding domains of all SHRs had potential for colocalization with HAP1/STBs, whereas only AR and GR were clearly colocalized with HAP1/STBs when each full-length SHR was coexpressed with HAP1. In addition, it appeared that HAP1/STBs did not disrupt GR and AR functions because the receptors on HAP1/STBs maintained nuclear translocation activity in response to their specific ligands. When the cells were treated with a proteasome inhibitor, GR and AR localized outside HAP1/STBs translocated into the nucleus, whereas the receptors colocalized with HAP1/STBs persisted in their colocalization even after treatment with their ligands. Therefore, HAP1/STBs may be involved in cytoplasmic modifications of the nuclear translocation of GR and AR in a ubiquitin-proteasome system.

Detection of immunoglobulins containing plasma cells in the thymus, bursa of Fabricius and spleen of vaccinated broiler chickens with Newcastle disease virus vaccine

Abstract Mobilization of immunoglobulins (Igs)-containing plasma cells (IgA, IgG and IgM) in the spleen, bursa of Fabricius and thymus was investigated in broiler chickens that were vaccinated with Newcastle disease virus (NDV) vaccine. In the thymus, the Igs-containing plasma cells were distributed in the cortex and medulla. Their frequency and distribution were higher at D14 and at D28. The number of IgG- and IgM-positive cells was greater than IgA-positive cells in thymus. In the bursa of Fabricius, Igs-containing plasma cells were distributed beneath the capsules; within and around the bursal follicles. Their frequency of occurrence significantly peaked at D14 and at D28 in comparison to day-old chickens, and IgG-positive cells were significantly greater than the IgA- and IgM-positive cells in the bursa of vaccinated chickens. In the spleen, Igs-containing plasma cells were distributed in the white pulp, around the trabeculae, and in the periarterial lymphatic sheath. In this secondary lymphatic tissue, IgG- and IgM-positive cell numbers significantly greater than IgA-positive cells. In conclusion, mobilization of more Igs-positive cells in lymphoid tissues of broiler chickens is due to the effect of NDV vaccine as well as the advancement of age.

Ontogenic development of immunoglobulins (Igs)-positive lymphocytes in the lymphoid organs of native chickens of Bangladesh

Abstract The first appearance, distribution and frequency of immunoglobulins (Igs)-positive lymphocytes were investigated in the lymphoid organs of native chicken’s embryos from embryonic day (ED) 8 to ED 20. The tissues from the lymphoid organs were dehydrated in alcohol, cleared in xylene, embedded in different grades of paraffin and 6-micron thick sections were immunostained by the indirect immunoperoxidase method using antichicken immunoglobulins. IgM-positive lymphocytes were first identified in the follicles of bursa of Fabricius at ED 10, in the white pulp of the spleen at ED 14 and in the lamina propria of the cecal tonsil at ED 20. Their frequencies of populations were statistically significant from ED 14 to ED 20. IgG-positive lymphocytes were first appeared in the bursa of Fabricius and spleen at ED 20. In the bursa IgG-positive lymphocytes were located in the medulla and cortical part of the follicles, whereas, in the spleen these immune cells were located around the white pulp. IgA-positive lymphocytes were not observed in any of the developing lymphoid organs of the present study. When the data for bursa of Fabricius, spleen, thymus and cecal tonsil were statistically compared, it was observed that both IgM- and IgG-positive lymphocytes were significantly higher in bursa of Fabricius.

Androgen receptor expression in the preoptic and anterior hypothalamic areas of the adult Wistar rat and C57BL/6 mouse

cess of the severe stress response. To study the physiological roles of OT in the hypothalamo–neurohypophysial system, we adopted the experimental paradigm of SPS. In this paradigm, Sprague-Dawley male rats were exposed to SPS (immobilization for 2 hr, forced swimming for 20 min, followed by ether anesthesia). The rats were then maintained in an undisturbed condition for either 3-day or 7-day recovery period. Fluorescent immunohistochemistry for OT, in combination with morphometrical analysis, revealed that the OT immunoreactivity in magnocellular neurons in the SON was significantly decreased by Day 7. Neuronal OT levels in the SON on Day 7 were reduced by about 21% compared with those of control. This study suggests that SPS exposure causes long-term suppression of OT expression in the SON neurons. Further studies on expression and function of central OT in SPS-exposed rats will lead to a better understanding of patho-physiological roles of OT in stress-related mental disorders.

Immunohistochemical analysis of huntingtin-associated protein 1 in adult rat spinal cord and its regional relationship with androgen receptor

Huntingtin-associated protein 1 (HAP1) is a neuronal interactor with causatively polyglutamine (polyQ)-expanded huntingtin in Huntingtons disease and also associated with pathologically polyQ-expanded androgen receptor (AR) in spinobulbar muscular atrophy (SBMA), being considered as a protective factor against neurodegenerative apoptosis. In normal brains, it is abundantly expressed particularly in the limbic-hypothalamic regions that tend to be spared from neurodegeneration, whereas the areas with little HAP1 expression, including the striatum, thalamus, cerebral neocortex and cerebellum, are targets in several neurodegenerative diseases. While the spinal cord is another major neurodegenerative target, HAP1-immunoreactive (ir) structures have yet to be determined there. In the current study, HAP1 expression was immunohistochemically evaluated in light and electron microscopy through the cervical, thoracic, lumbar, and sacral spinal cords of the adult male rat. Our results showed that HAP1 is specifically expressed in neurons through the spinal segments and that more than 90% of neurons expressed HAP1 in lamina I-II, lamina X, and autonomic preganglionic regions. Double-immunostaining for HAP1 and AR demonstrated that more than 80% of neurons expressed both in laminae I-II and X. In contrast, HAP1 was specifically lacking in the lamina IX motoneurons with or without AR expression. The present study first demonstrated that HAP1 is abundantly expressed in spinal neurons of the somatosensory, viscerosensory, and autonomic regions but absent in somatomotor neurons, suggesting that the spinal motoneurons are, due to lack of putative HAP1 protectivity, more vulnerable to stresses in neurodegenerative diseases than other HAP1-expressing neurons probably involved in spinal sensory and autonomic functions.