PMID- 8887272
OWN - NLM
STAT- MEDLINE
DCOM- 19970310
LR  - 20190725
IS  - 0085-2538 (Print)
IS  - 0085-2538 (Linking)
VI  - 50
IP  - 4
DP  - 1996 Oct
TI  - Modulation of hypoxia-induced calpain activity in rat renal proximal tubules.
PG  - 1150-7
AB  - The effect of the newly developed, nonpeptide, calpain inhibitor, PD 150606, on 
      hypoxia and ionomycin-induced increases in calpain activity in rat proximal 
      tubules (PT) was determined. PD150606 inhibited both hypoxia and 
      ionomycin-induced calpain activity as determined by the fluorescent substrate 
      N-succinyl-Leu-Leu-Val-Tyr-7-amido-4-methyl coumarin 
      (N-succinyl-Leu-Leu-Val-Tyr-AMC). This decrease in calpain activity was 
      accompanied by dose-dependent cytoprotection against hypoxia and 
      ionomycin-induced cell membrane damage. PD150606 had no effect on cathepsin B and 
      L activity in PT as measured by the fluorescent substrate, 
      benzyloxycarbonyl-L-phenylalanyl-L-arginine-7-amido-4-methyl coumarin 
      (Z-Phe-Arg-AMC). The effects of low intracellular pH (pHi) or low free cytosolic 
      calcium [Ca2+]i on this hypoxia-induced calpain activity were also determined. 
      Both low pHi and low [Ca2+]i attenuated the hypoxia-induced increase in calpain 
      activity. This attenuation of calpain activity was observed early before 
      hypoxia-induced membrane damage and was associated with marked reduction in the 
      typical pattern of hypoxia-induced cell membrane damage observed in this model. 
      To identify the isoform of calpain activated in rat proximal tubules, normoxic, 
      hypoxic and ionomycin treated tubules were fractionated by MONO-Q anion exchange 
      chromatography and the fractions were assayed for calpain activity. A single peak 
      of calpain activity characteristic of mu-calpain was found. The calcium 
      dependency of the calpain activity was in the nanomolar range, further confirming 
      that the activity was the low Ca(2+)-sensitive mu-calpain. The present study 
      suggests that in rat proximal tubules: (1) PD 150606 is a specific inhibitor of 
      calpain and not cathepsins B and L; (2) the cytoprotective effects of low pHi and 
      low [Ca2+]i are mediated, at least in part, by inhibition of calpain activity; 
      and (3) the predominant active form of calpain is the isoenzyme mu-calpain.
FAU - Edelstein, C L
AU  - Edelstein CL
AD  - Department of Medicine, University of Colorado School of Medicine, Denver, USA.
FAU - Yaqoob, M M
AU  - Yaqoob MM
FAU - Alkhunaizi, A M
AU  - Alkhunaizi AM
FAU - Gengaro, P E
AU  - Gengaro PE
FAU - Nemenoff, R A
AU  - Nemenoff RA
FAU - Wang, K K
AU  - Wang KK
FAU - Schrier, R W
AU  - Schrier RW
LA  - eng
GR  - DK35098/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Kidney Int
JT  - Kidney international
JID - 0323470
RN  - 0 (Acrylates)
RN  - 0 (PD 150606)
RN  - EC 1.1.1.27 (L-Lactate Dehydrogenase)
RN  - EC 3.4.- (Cathepsins)
RN  - EC 3.4.22.- (Calpain)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Acrylates/pharmacology
MH  - Analysis of Variance
MH  - Animals
MH  - Calcium/physiology
MH  - Calpain/antagonists & inhibitors/chemistry/*metabolism
MH  - Cathepsins/analysis
MH  - Dose-Response Relationship, Drug
MH  - Hydrogen-Ion Concentration
MH  - Hypoxia/*metabolism
MH  - In Vitro Techniques
MH  - Kidney Tubules, Proximal/*enzymology
MH  - L-Lactate Dehydrogenase/analysis
MH  - Male
MH  - Rats
MH  - Rats, Sprague-Dawley
EDAT- 1996/10/01 00:00
MHDA- 1996/10/01 00:01
CRDT- 1996/10/01 00:00
PHST- 1996/10/01 00:00 [pubmed]
PHST- 1996/10/01 00:01 [medline]
PHST- 1996/10/01 00:00 [entrez]
AID - S0085-2538(15)59716-0 [pii]
AID - 10.1038/ki.1996.422 [doi]
PST - ppublish
SO  - Kidney Int. 1996 Oct;50(4):1150-7. doi: 10.1038/ki.1996.422.