Expression of Insulin-Like Growth Factor Binding Protein-2 during Postnatal Development of the Rat Neurointermediate Pituitary

Zhou, Xinrong; Herman, James P.; Paden, Charles M.

doi:10.1159/000127214

Cited by 8 publications

(4 citation statements)

References 38 publications

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“…As demonstrated in Figure 3G, no colocalization was evident when binding of OX-42 (red, CY-3) was localized simultaneously with anti-hrIL-1␤ (green, FITC) using confocal microscopy. Similar results were obtained when binding of antisera to S100, an astrocytespecific Ca ϩϩ -binding protein (Cocchia and Miana, 1980;Zhou et al, 1997), was colocalized with binding of antihrIL-1␤. As illustrated in Figure 3H, no colocalization of S100-ir (red, CY-3) and anti-IL-1␤-ir (green, FITC) was evident.…”

Section: Il-1␤ Immunoreactivity Does Not Colocalize With Pituicytes Osupporting

confidence: 78%

Interleukin-1? immunoreactivity in identified neurons of the rat magnocellular neurosecretory system: Evidence for activity-dependent release

Watt

Hobbs

2000

J. Neurosci. Res.

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Interleukin-1beta has been demonstrated in neurons of the rat hypothalamus, including cells of the magnocellular neurosecretory system and tuberoinfundibular system (Lechan et al., [1990] Brain Res. 514:135-140). Despite its potential importance to regulation of neuroendocrine function, however, neither the specific cell types that express interleukin-1beta or the conditions that may result in its release have yet been described. Therefore, we utilized a combination of immunocytochemical and immunoelectron microscopic localization, in conjunction with Western blot analysis, on normonatremic, hypernatremic, and lactating rats to assess the site of synthesis and potential secretion characteristics of interleukin-1beta in the rat magnocellular neurosecretory system. Interleukin-1beta immunoreactivity was localized within both oxytocin and vasopressin neurons in the paraventricular, supraoptic, accessory and periventricular hypothalamic nuclei. Additionally, interleukin-1beta immunoreactive fibers were localized in the zona interna and zona externa of the median eminence and in the neurohypophysis. Immunoelectron microscopic analysis revealed that interleukin-1beta immunoreactivity is associated with small spherical structures, distinct from neurosecretory granules, in neurosecretory axons within the neurohypophysis. Furthermore, stimulation of heightened neurosecretory activity via chronic osmotic challenge and lactation resulted in a marked diminution in levels of interleukin-1beta immunoreactivity in the neurohypophysis with a subsequent return to normal levels after cessation of the stimuli. Western blot analysis confirmed the existence of interleukin-1beta protein in the neurohypophysis and provided further evidence for reduction in levels of IL-1beta immunoreactivity after stimulation of secretory activity. These results suggest an endogenous neuronal source of interleukin-1beta exists within the rat magnocellular neurosecretory system under normal physiological conditions. The potential for activity-dependent release of IL-1beta and implications for the involvement of interleukin-1beta in regulation of neurosecretory activity are discussed.

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Section: Il-1␤ Immunoreactivity Does Not Colocalize With Pituicytes Osupporting

confidence: 78%

Interleukin-1? immunoreactivity in identified neurons of the rat magnocellular neurosecretory system: Evidence for activity-dependent release

Watt

Hobbs

2000

J. Neurosci. Res.

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“…Hypertrophic astrocytes at the lesion edges of MS plaques showed enhanced expression of IGFBP‐2 and IGFBP‐4. IGFBP‐2 is highly expressed in the CNS, and is the major IGFBP in cerebrospinal fluid (Kelly et al ., 1996; Zhou et al ., 1997). We have previously shown that reactive microglia and macrophages in MS lesions also display enhanced immunoreactivity for IGFBP‐2 (Chesik et al ., 2004a).…”

Section: Discussioncontrasting

confidence: 99%

Insulin‐like growth factor binding proteins: regulation in chronic active plaques in multiple sclerosis and functional analysis of glial cells

Chesik

Keyser

Glazenburg

et al. 2006

Eur J of Neuroscience

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Studies in experimental allergic encephalomyelitis, an animal model of multiple sclerosis (MS), suggest that astrocyte-secreted insulin-like growth factor binding protein-2 (IGFBP-2) helps target IGF-1 to IGF-1 receptor-expressing oligodendrocytes and promote remyelination. We examined the presence of IGFBPs 1-6 in astrocytes in normal post-mortem human brain tissue and lesions of MS by means of immunohistochemistry. Under normal conditions all six IGFBPs were detected. Compared to controls, hypertrophic astrocytes at the borders of chronic active MS lesions displayed increased immunoreactivity for IGFBP-2 and IGFBP-4. In vitro studies were performed to analyse the effects of IGFBPs on cellular proliferation of neonatal rat glial cells. Treatment of astrocytes with IGF-1 and -2 enhanced proliferation whereas IGFBP-2 and -4 inhibited cellular growth. Interestingly, combined treatment with IGFBP-2 and IGF-1 potentiated effects on cellular proliferation whereas combined treatment with IGFBP-2 and IGF-2 inhibited growth. Unlike IGFBP-2, IGFBP-4 inhibited proliferation in combined treatment with IGF-1. In contrast, combined treatment with IGFBP-2 and IGF-1 resulted in decreased cell survival of oligodendrocyte precursor cells. Our results suggest that the up-regulation of IGFBP-2 in reactive astrocytes in MS lesions may primarily serve to enhance the IGF-1-mediated mitogenic stimulus for astrocytes rather than supporting oligodendrocyte survival.

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“…In order to further define the cell type(s) expressing the p75 NTR , we performed dual confocal fluorescence localizations pairing anti-S100, an astrocyte-specific Ca 2+ -binding protein (Cocchia and Miana 1980;Zhou et al 1997), and p75 NTR in NL. As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Upregulation of the p75 low-affinity neurotrophin receptor by phagocytically active perivascular cells in the rat neural lobe

Watt

Paden

2001

Cell and Tissue Research

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Expression of the p75 low-affinity neurotrophin receptor (p75NTR) was investigated immunocytochemically at the light and ultrastructural level during the axonal degeneration that follows partial denervation of the rat neural lobe (NL) and following systemic administration of lipopolysaccharide (LPS). A significant increase in the intensity and extent of p75NTR immunoreactivity in the NL of partially denervated animals compared with age-matched, sham-operated controls was observed at 5-10 days postdenervation, with immunoreactivity returning to control values by 35 days. Dual-label confocal comparison of p75NTR localization with that of the C3bi complement receptor, a microglial marker, and S100, an astrocyte-specific Ca2+-binding protein, revealed no colocalization. Immunoelectron-microscopic examination demonstrated that the p75NTR immunoreactivity is present in a subpopulation of cells located within the extensive perivascular space of the NL. No examples of p75NTR-immunoreactive pituicytes or endothelia were observed at the light or ultrastructural level. Dense p75NTR immunoreactivity was frequently observed surrounding endocytotic omega profiles of plasmalemma engulfing extracellular debris as well as lining vacuoles within the cytoplasm of perivascular cells. The association of p75NTR with phagocytosis was confirmed by confocal microscopy, showing the presence of p75NTR in all cells expressing the ED-1 antigen, which is restricted to the lysosomal membrane of phagocytes (Damoiseaux et al. 1994). Likewise, a marked increase in p75NTR and ED-1 immunoreactivity was observed in the NL following systemic administration of LPS. These results suggest a strong correlation between modulation of p75NTR immunoreactivity and conditions that induce high levels of phagocytic activity by perivascular cells in the NL of the rat. Implications for understanding the mechanisms by which phagocytes may support compensatory responses to neuronal injury are discussed.

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Expression of Insulin-Like Growth Factor Binding Protein-2 during Postnatal Development of the Rat Neurointermediate Pituitary

Cited by 8 publications

References 38 publications

Interleukin-1? immunoreactivity in identified neurons of the rat magnocellular neurosecretory system: Evidence for activity-dependent release

Interleukin-1? immunoreactivity in identified neurons of the rat magnocellular neurosecretory system: Evidence for activity-dependent release

Insulin‐like growth factor binding proteins: regulation in chronic active plaques in multiple sclerosis and functional analysis of glial cells

Upregulation of the p75 low-affinity neurotrophin receptor by phagocytically active perivascular cells in the rat neural lobe

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