Coregulation of Neurite Outgrowth and Cell Survival by Amphoterin and S100 Proteins through Receptor for Advanced Glycation End Products (RAGE) Activation

Abstract

Amphoterin is a protein enhancing process extension and migration in embryonic neurons and in tumor cells through binding to receptor for advanced glycation end products (RAGE), a multiligand transmembrane receptor. S100 proteins, especially S100B, are abundantly expressed in the nervous system and are suggested to function as cytokines with both neurotrophic and neurotoxic effects. However, the cell surface receptor for the cytokine function of S100B has not been identified. Here we show that two S100 family proteins, S100B and S100A1, activate RAGE in concert with amphoterin inducing neurite outgrowth and activation of transcription factor NF-B. Furthermore, activation of RAGE by amphoterin and S100B promotes cell survival through increased expression of the anti-apoptotic protein Bcl-2. However, whereas nanomolar concentrations of S100B induce trophic effects in RAGE-expressing cells, micromolar concentrations of S100B induce apoptosis in an oxidant-dependent manner. Both trophic and toxic effects are specific for cells expressing full-length RAGE since cells expressing a cytoplasmic domain deletion mutant of RAGE are unresponsive to these stimuli. These findings suggest that activation of RAGE by multiple ligands is able to promote trophic effects whereas hyperactivation of RAGE signaling pathways promotes apoptosis. We suggest that RAGE is a signal-transducing receptor for both trophic and toxic effects of S100B.Receptor for advanced glycation end products (RAGE) 1 is a member of the immunoglobulin superfamily of cell surface proteins interacting with a range of ligands, including advanced glycation end products (AGE) (1), amyloid-␤ peptide (2), amphoterin (3), and members of the S100 family (4). Whereas AGE and amyloid-␤ peptide are known to induce cellular perturbation through their interaction with RAGE, amphoterin and S100 proteins are considered to be physiological ligands of RAGE in migratory and inflammatory cellular responses. However, mechanistically it is not understood how RAGE-mediated cellular responses can change from trophic to toxic.Amphoterin is a heparin-binding, neurite outgrowth-promoting protein that is highly expressed in embryonic and transformed cells (5-7). RAGE has been shown to mediate neurite outgrowth of cortical neurons and neuroblastoma cells on amphoterin-coated substrates (3, 8). Furthermore, amphoterin and RAGE co-localize at the leading edge of advancing neurites in the developing central nervous system (3). Our previous results suggesting that amphoterin might be a more general regulator of cell migration (reviewed in Ref. 9) are supported by the recent findings showing that blockade of amphoterin-RAGE interaction decreases invasion and growth of both implanted and spontaneously developing tumors (10). S100B is a member of a multigenic family of Ca 2ϩ -regulated proteins of the EF-hand type that has been implicated in the regulation of protein phosphorylation, the dynamics of cytoskeleton constituents, the cell cycle, and some enzymes (11,12). S100B is abundant in the n...

Amphoterin Stimulates Myogenesis and Counteracts the Antimyogenic Factors Basic Fibroblast Growth Factor and S100B via RAGE Binding

“…We also show that the Ca 2ϩ -modulated protein S100B, which is another RAGE ligand (20,23), which, however, inhibits L6 myoblast differentiation in a RAGE-independent manner (51), counteracts the stimulatory activity of amphoterin (Fig. 5).…”

“…Experiments were performed on wild-type (WT), mock-transfected, L6/RAGE, and L6/RAGE⌬cyto myoblasts in 2% FBS unless stated otherwise. Recombinant S100B was expressed, purified, and characterized as described previously (23). bFGF was from Sigma Chemical.…”

“…S100B was shown to bring about these inhibitory effects by inactivating p38 MAPK. While in other cell types responsive to S100B such as neurons and microglia the receptor for advanced glycation end products (RAGE) was demonstrated to bind S100B and to transduce the regulatory effects of S100B (20,23) and while myoblasts were observed to express RAGE (mRNA and protein) constitutively (51), no such role for RAGE could be documented in the case of the inhibitory effects of S100B on myoblasts. In fact, S100B inhibited myoblast differentiation and myotube formation in L6 myoblasts stably overexpressing either full-length RAGE (L6/RAGE myoblasts) or a RAGE mutant lacking the cytoplasmic and transducing domain (L6/ RAGE⌬cyto myoblasts) (51).…”

“…In fact, other members of the immunoglobulin superfamily have been shown to play a role in neuronal and skeletal muscle development (6,27,41,46). Besides transducing effects of AGEs and ␤-amyloid (34,60,65), RAGE has been shown to transduce the effects of amphoterin (HMGB1), a protein with both intracellular and extracellular regulatory activities (38,58), on neurons and astrocytes (21)(22)(23)54), and S100A12, another member of the S100 protein family (11,19), on inflammatory cells (20). It is known that RAGE is expressed in several cell types during development, is repressed or down-regulated at completion of development, and is reexpressed in adulthood in the course of certain pathological conditions, including neurodegeneration, inflammation, and cancer (48,49).…”

Calcium-Binding Proteins S100A8 and S100A9 as Novel Diagnostic Markers in Human Prostate Cancer

“…For several members of the S100 protein family, a function as ligands for the receptor for advanced glycation end products (RAGE) has been discussed (25,26). RAGE is a cell surface molecule that has been described as a multiligand receptor of the immunoglobulin superfamily.…”