oxalylglycine and Acute-Disease

Although epilepsy is a common neurological disorder, its mechanism(s) are still not completely understood. Hypoxia can lead to neuronal cell death and angiogenesis, and the same mechanisms were also found in epilepsy. Hypoxia-inducible factor-1α (HIF-1α) is an important transcription protein that regulates gene expression in the brain and other tissues in response to decreases in oxygen availability. However, little is known regarding the expression of HIF-1α in the epileptic brain and whether HIF-1α interventions affect the epileptic process. The aims of this study are to investigate the expression profile of HIF-1α in rat models and to explore the role of HIF-1α in epilepsy. We performed Western blots and immunofluorescence in a lithium-pilocarpine rat epilepsy model. To determine the role of HIF-1α in epilepsy, we used the HIF-1α agonist DMOG and inhibitor KC7F2 to detect changes in the animal behavior in pentylenetetrazole (PTZ) and lithium-pilocarpine epilepsy models. The expression of HIF-1α was significantly increased after pilocarpine-induced status epilepticus. DMOG significantly prolonged the latent period in the PTZ kindling model and decreased the rate of spontaneous recurrent seizures during the chronic stage in the lithium-pilocarpine model. Conversely, the inhibitor KC7F2 produced an opposite behavioral change. Interestingly, both KC7F2 and DMOG had no effect on the acute stage of pilocarpine model and PTZ convulsive model. Our study suggests that upregulated HIF-1α may be involved in the process of epileptogenesis but not in the acute stage of epilepsy. The modulation of HIF-1α may offer a novel therapeutic target in epilepsy.

Topics: Acute Disease; Amino Acids, Dicarboxylic; Animals; Brain; Central Nervous System Agents; Chronic Disease; Disease Models, Animal; Disulfides; Epilepsy; Hypoxia-Inducible Factor 1, alpha Subunit; Lithium Compounds; Male; Pentylenetetrazole; Pilocarpine; Random Allocation; Rats, Sprague-Dawley; Seizures; Status Epilepticus; Sulfonamides

Myeloid cells recruited to sites of bacterial inflammation are exposed to low oxygen tension, hypoxia, and high concentrations of inflammatory cytokines that significantly affect myeloid cell function. Therefore, we analyzed the direct consequences of acute and severe hypoxia on monocytic adhesion to the endothelium in coculture experiments. Marked upregulation of monocytic ICAM-1, but no other monocytic adhesion molecule, was responsible for an approximately 50-fold increase in adhesion of the monocytic cells THP-1 to human and rat endothelial cells. ICAM-1 expression was rapidly induced after the onset of severe hypoxia, but it decreased after 4 h. Knockdown of ICAM-1 by siRNA in endothelial and monocytic cells abolished the adhesion, indicating that ICAM-1 expression on both cell types was indispensable for hypoxia-induced adhesion of monocytes to the endothelium. siRNA-mediated knockdown of hypoxia inducible factor (HIF)-1alpha, HIF-2alpha, and the NF-kappaB family member p65 revealed that hypoxic upregulation of ICAM-1 resulted from hypoxic NF-kappaB induction but not from activation of HIFs. Within the leukocyte-adhesion cascade, our results provide evidence for prolyl hydroxylase-dependent but HIF-independent activation of hypoxia-induced monocyte-endothelial adhesion and assign a new function to monocytic ICAM-1 under acute hypoxic conditions.

Topics: Acute Disease; Amino Acids, Dicarboxylic; Animals; Basic Helix-Loop-Helix Transcription Factors; Cell Adhesion; Cell Hypoxia; Cell Line; Cell Line, Tumor; Coculture Techniques; Endothelium, Vascular; Enzyme Activation; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Intercellular Adhesion Molecule-1; Monocytes; NF-kappa B; Procollagen-Proline Dioxygenase; Rats; RNA, Messenger; Up-Regulation