The Protective Effects of the Proteasome Inhibitor Bortezomib (Velcade) on Ischemia-Reperfusion Injury in the Rat Retina

Abstract

PurposeTo evaluate the protective effects of bortezomib (Velcade) on ischemia-reperfusion (IR) injury in the rat retina.MethodsThe rats were randomized to receive treatment with saline, low-dose bortezomib (0.05 mg/kg), or high-dose bortezomib (0.2 mg/kg) before the induction of IR injury. Electroretinography (ERG) was used to assess functional changes in the retina. The expression of inflammatory mediators (iNOS, ICAM-1, MCP-1, TNF-α), anti-oxidant proteins (heme oxygenase, thioredoxin, peroxiredoxin), and pro-apoptotic proteins (p53, bax) were quantified by PCR and western blot analysis. An immunofluorescence study was performed to detect the expression of iNOS, oxidative markers (nitrotyrosine, 8-OHdG, acrolein), NF-κB p65, and CD 68. Apoptosis of retinal cells was labeled with in situ TUNEL staining. Neu-N staining was performed in the flat-mounted retina to evaluate the density of retinal ganglion cells.ResultsERG showed a decreased b-wave after IR injury, and pretreatment with bortezomib, especially the high dosage, reduced the functional impairment. Bortezomib successfully reduced the elevation of inflammatory mediators, anti-oxidant proteins, pro-apoptotic proteins and oxidative markers after IR insult in a dose-dependent manner. In a similar fashion, NF-κB p65- and CD 68-positive cells were decreased by bortezomib treatment. Retinal cell apoptosis in each layer was attenuated by bortezomib. The retinal ganglion cell density was markedly decreased in the saline and low-dose bortezomib groups but was not significantly changed in the high-dose bortezomib group.ConclusionsBortezomib had a neuro-protective effect in retinal IR injury, possibly by inhibiting the activation of NF-κB related to IR insult and reducing the inflammatory signals and oxidative stress in the retina.

Single cell imaging of the heat shock response during proteasome inhibitor-induced apoptosis in colon cancer cells suggests that magnitude and length rather than time of onset determines resistance to apoptosis

“…In fact, there was minimal cell death induced in the concentration range of 0-30 nM epoxomicin. Indeed, this is in line with previous studies that demonstrate that the use of low concentrations or reversible proteasome inhibitors can induce cytoprotection to subsequent stimuli (Bardag-Gorce et al, 2011;Chen et al, 2013;Stankova et al, 2013). Only at higher concentrations (40-50 nM), when the maximum threshold for HSP70 promoter activity was reached, did significant increases in levels of cell death occur.…”

Albumin Cys34 adducted by acrolein as a marker of oxidative stress in ischemia-reperfusion injury during hepatectomy

“…Others have demonstrated that ACR is released after I/R damage in the heart [37] and in the retina of rats [38]. Here, we first demonstrated, to our knowledge, that ACR is the main RCS formed during liver reperfusion in humans.…”

Impact of proteasome inhibitor MG‑132 on expression of NF‑κB, IL‑1β and histological remodeling after myocardial infarction

“…Santos et al (10) reported that the proteasome inhibitor MLN519 inhibits the activation of NF-κB, thus reducing the expression of inflammatory cytokines TNF-α, IL-1β and IL-6 and reducing myocardial ischemia-reperfusion injury. Chen et al (11) obtained similar results with carbobenzoxy-Leu-Leu-leucinal (MG-132). However, to the best of our knowledge, no previous study has reported on the application of proteasome inhibitors toward post-MI myocardial remodeling.…”

“…The present study also demonstrated that after MG-132 was applied, the expression of MMP-2 reduced in parallel with the decrease of NF-κB, IL-1β and the deposition of total collagen, type I collagen and type I/III collagen in the non-MI zone was significantly reduced, indicating that this pathway improves collagen remodeling in the non-MI zone. While previous studies reported that MG-132 attenuated myocardial hypertrophy and collagen remodeling by decreasing the expression of IL-1β, no direct evidence regarding inhibition of NF-κB was ever provided (4,11). In the present study, by measuring the gene and protein expression of NF-κB and its downstream products IL-1β and MMP-2 and analyzing their association with myocardial remodeling in the non-MI zone, it was confirmed that the mechanisms by which MG-132 inhibited post-MI myocardial remodeling included the reduction of NF-κB activation and the downregulation of inflammatory factors.…”