Derivatives of Erythropoietin That Are Tissue Protective But Not Erythropoietic
Erythropoietin (EPO) is both hematopoietic and tissue protective, putatively through interaction with different receptors. We generated receptor subtype–selective ligands allowing the separation of EPO's bioactivities at the cellular level and in animals. Carbamylated EPO (CEPO) or certain EPO mutants did not bind to the classical EPO receptor (EPOR) and did not show any hematopoietic activity in human cell signaling assays or upon chronic dosing in different animal species. Nevertheless, CEPO and various nonhematopoietic mutants were cytoprotective in vitro and conferred neuroprotection against stroke, spinal cord compression, diabetic neuropathy, and experimental autoimmune encephalomyeli…
Conversion of Nonproliferating Astrocytes into Neurogenic Neural Stem Cells: Control by FGF2 and Interferon-gamma
Abstract Conversion of astrocytes to neurons, via de-differentiation to neural stem cells (NSC), may be a new approach to treat neurodegenerative diseases and brain injuries. The signaling factors affecting such a cell conversion are poorly understood, and they are hard to identify in complex disease models or conventional cell cultures. To address this question, we developed a serum-free, strictly controlled culture system of pure and homogeneous “astrocytes generated from murine embryonic stem cells (ESC).” These stem cell derived astrocytes (mAGES), as well as standard primary astrocytes resumed proliferation upon addition of FGF. The signaling of FGF receptor tyrosine kinase converted G…
Concanavalin A?induced T-cell?Mediated hepatic injury in mice: The role of tumor necrosis factor*1
Concanavalin A activates T lymphocytes in vitro and causes T-cell-dependent hepatic injury in mice. T lymphocytes were previously identified as effector cells of concanavalin A-induced liver injury. Here we report that hepatic injury is characterized by apoptotic cell death. On concanavalin A challenge, the cytokines tumor necrosis factor-alpha (TNF alpha), interleukin-2, granulocyte macrophage-colony stimulating factor, and interferon-gamma were detectable in the circulation of the mice. Pretreatment of mice with anti-mouse TNF-alpha antiserum protected them from concanavalin A-induced liver injury. Nude mice failed to release TNF-alpha or interleukin-2 after concanavalin A challenge and w…