Effect of growth factors and steroids on transglutaminase activity and expression in primary astroglial cell cultures

Abstract

Type-2 transglutaminase (TG-2) is a multifunctional enzyme involved in the regulation of cell differentiation and survival that recently has been shown to play an emerging role in astrocytes, where it is involved in both proliferation and differentiation processes. Growth factors (GFs) such as EGF, basic fibroblast growth factor, insulin-like growth factor-I (IGF-I), and insulin (INS) are trophic and mitogenic peptides that participate in neuron-glia interactions and stimulate neuronal and astroglial proliferation and differentiation. Steroid hormones such as glucocorticoids and estrogens also play a pivotal role in neuronal and astroglial proliferation and differentiation and are key hormones in neurodegenerative and neuroprotective processes. We investigated the effects of the interaction of GFs with dexamethasone (DEX) or 17beta-estradiol (E(2)) on TG-2 activity and their expression in cultured astrocytes. We observed a significant increase in TG-2 activity and expression in astroglial cells treated for 24 hr with IGF-I, EGF, or INS. Priming of the cells with DEX or E(2), for 48 hr also led to an increase in TG-2 levels. When growth factors were present in the last 24 hr of the steroid treatment, a reduction in TG-2 expression and activity and a different subcellular TG-2 distribution were found. Our data indicate that steroid hormone-GF interaction may play an important role in astroglial function. The effect on TG-2 could be part of the regulation of intracellular pathways associated with the astrocyte response observed in physiological conditions and, possibly, also in neuropathological diseases.

Serum deprivation alters lipid profile in HN9.10e embryonic hippocampal cells

“…Serum deprivation is able to enhance spontaneous or growth factor-induced differentiation in neural cells, including astrogial cells [16,17] but no data exist on the effect of serum deprivation on lipid profile so far. In the present paper, we have investigated this aspect in HN9.10e cells by UFLC-MS/MS.…”

Complete transglutaminase 2 ablation results in reduced stroke volumes and astrocytes that exhibit increased survival in response to ischemia

“…In neurons, TG2 was found to be protective against ischemic cell death both in vitro and in vivo (Filiano et al, 2008; Filiano et al, 2010). Although TG2 is present in astrocytes and is upregulated in response to different stressors (Caccamo et al, 2005; Campisi et al, 2008; Campisi et al, 2004; Monsonego et al, 1997), how TG2 affects survival of astrocytes in response to ischemia has not been investigated. Astrocytes likely play a critical role in the pathogenesis of ischemia-induced neuronal cell death (Takano et al, 2009); therefore it is important to understand how TG2 impacts cell death processes in both neurons and astrocytes.…”

Effect of Acetylcholine Precursors on Proliferation and Differentiation of Astroglial Cells in Primary Cultures

“…In our previous researches [5,6,9] we reported findings showing growth rate and differentation of astroglial cells in culture. In particular, it has been evaluated DNA and RNA lobeling and ERK1 immunoactiviy in astrocyte cultures preatrated with growth factors (GFs) and treated with astroglial conditioned media (ACM) [5] and it has been found an up and down regulation of nucleic acid labelling.…”