title: Dipeptidyl peptidase IV, aminopeptidase N and DPIV/APN-like proteases in cerebral ischemia.
abstract: BACKGROUND
  Cerebral inflammation is a hallmark of neuronal degeneration. Dipeptidyl peptidase IV, aminopeptidase N as well as the dipeptidyl peptidases II, 8 and 9 and cytosolic alanyl-aminopeptidase are involved in the regulation of autoimmunity and inflammation. We studied the expression, localisation and activity patterns of these proteases after endothelin-induced occlusion of the middle cerebral artery in rats, a model of transient and unilateral cerebral ischemia.
  
  
  METHODS
  Male Sprague-Dawley rats were used. RT-PCR, immunohistochemistry and protease activity assays were performed at different time points, lasting from 2 h to 7 days after cerebral ischemia. The effect of protease inhibitors on ischemia-dependent infarct volumes was quantified 7 days post middle cerebral artery occlusion. Statistical analysis was conducted using the t-test.
  
  
  RESULTS
  Qualitative RT-PCR revealed these proteases in ipsilateral and contralateral cortices. Dipeptidyl peptidase II and aminopeptidase N were up-regulated ipsilaterally from 6 h to 7 days post ischemia, whereas dipeptidyl peptidase 9 and cytosolic alanyl-aminopeptidase were transiently down-regulated at day 3. Dipeptidyl peptidase 8 and aminopeptidase N immunoreactivities were detected in cortical neurons of the contralateral hemisphere. At the same time point, dipeptidyl peptidase IV, 8 and aminopeptidase N were identified in activated microglia and macrophages in the ipsilateral cortex. Seven days post artery occlusion, dipeptidyl peptidase IV immunoreactivity was found in the perikarya of surviving cortical neurons of the ipsilateral hemisphere, whereas their nuclei were dipeptidyl peptidase 8- and amino peptidase N-positive. At the same time point, dipeptidyl peptidase IV, 8 and aminopeptidase N were targeted in astroglial cells. Total dipeptidyl peptidase IV, 8 and 9 activities remained constant in both hemispheres until day 3 post experimental ischemia, but were increased (+165%) in the ipsilateral cortex at day 7. In parallel, aminopeptidase N and cytosolic alanyl-aminopeptidase activities remained unchanged.
  
  
  CONCLUSIONS
  Distinct expression, localization and activity patterns of proline- and alanine-specific proteases indicate their involvement in ischemia-triggered inflammation and neurodegeneration. Consistently, IPC1755, a non-selective protease inhibitor, revealed a significant reduction of cortical lesions after transient cerebral ischemia and may suggest dipeptidyl peptidase IV, aminopeptidase N and proteases with similar substrate specificity as potentially therapy-relevant targets.
authors.affiliation: KeyNeurotek Pharmaceuticals AG, Leipziger Str. 44, D-39120 Magdeburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Röhnert
authors.forename: Werner
authors.initials: W
authors.lastname: Schmidt
authors.forename: Patrick
authors.initials: P
authors.lastname: Emmerlich
authors.forename: Alexander
authors.initials: A
authors.lastname: Goihl
authors.forename: Sabine
authors.initials: S
authors.lastname: Wrenger
authors.forename: Ute
authors.initials: U
authors.lastname: Bank
authors.forename: Karsten
authors.initials: K
authors.lastname: Nordhoff
authors.forename: Michael
authors.initials: M
authors.lastname: Täger
authors.forename: Siegfried
authors.initials: S
authors.lastname: Ansorge
authors.forename: Dirk
authors.initials: D
authors.lastname: Reinhold
authors.forename: Frank
authors.initials: F
authors.lastname: Striggow
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000150:complications / Q000188:drug therapy / Q000201:enzymology*; D018826:CD13 Antigens / Q000235:genetics / Q000378:metabolism*; D002544:Cerebral Infarction / Q000201:enzymology / Q000209:etiology; D018819:Dipeptidyl Peptidase 4 / Q000235:genetics / Q000378:metabolism*; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D007839:Functional Laterality; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006028:Glycosphingolipids / Q000627:therapeutic use; D008297:Male; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D004791:Enzyme Inhibitors; D005904:Glial Fibrillary Acidic Protein; D006028:Glycosphingolipids; D012333:RNA, Messenger; C477937:inositolphosphorylceramide; D018826:CD13 Antigens; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C527707:Dpp8 protein, rat; D018819:Dipeptidyl Peptidase 4; D010751:Phosphopyruvate Hydratase