| First Author | Cai ZP | Year | 2008 |
| Journal | FASEB J | Volume | 22 |
| Issue | 12 | Pages | 4248-57 |
| PubMed ID | 18728217 | Mgi Jnum | J:146044 |
| Mgi Id | MGI:3836541 | Doi | 10.1096/fj.08-105940 |
| Citation | Cai ZP, et al. (2008) Ischemic preconditioning-induced cardioprotection is lost in mice with immunoproteasome subunit low molecular mass polypeptide-2 deficiency. FASEB J 22(12):4248-57 |
| abstractText | The ubiquitin-proteasome system plays an important role in many cellular processes through degradation of specific proteins. Low molecular mass polypeptide 2 (LMP-2 or beta(1i)) is one important subunit of the immunoproteasome. Ischemic preconditioning (IPC) activates cell signaling pathways and generates cardioprotection but has not been linked to LMP-2 function previously. LMP-2 knockout mice (C57BL6 background) and wild-type C57BL6 mice were subjected to 30 min of ischemia (I-30) and 120 min of reperfusion (R-120) with or without preceding IPC (10 min of infusion and 5 min of reperfusion). IPC significantly increased left ventricular developed pressure and decreased infarct size in wild-type mice, but this protective effect of IPC was lost in LMP-2 knockout mice. IPC-mediated degradation of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) and activation of the downstream protein kinase Akt were impaired in LMP-2 knockout hearts. The impairment of PTEN degradation was associated with defective immunoproteasomes and decreased proteolytic activities. When LMP-2 knockout mice were pretreated with the PTEN inhibitor bpV(HOpic), cardiac function was significantly improved, and myocardial infarct size was significantly reduced after I-30/R-120. In conclusion, LMP-2 is required for normal proteasomal function and IPC induction in the heart. Its action may be related to PTEN protein degradation. |
