Protective effect of a novel clinical-grade small molecule necrosis inhibitor against oxidative stress and inflammation during islet transplantation

Abstract

Inhibition of mitochondrial reactive oxygen species (ROS) and subsequent damage‐associated molecular patterns (DAMPs)‐induced inflammatory responses could be a novel target in clinical islet transplantation. We investigated the protective effects of NecroX‐7, a novel clinical‐grade necrosis inhibitor that specifically targets mitochondrial ROS, against primary islet graft failure. Islets from heterozygote human islet amyloid polypeptide transgenic (hIAPP+/−) mice and nonhuman primates (NHPs) were isolated or cultured with or without NecroX‐7 in serum‐deprived medium. Supplementation with NecroX‐7 during hIAPP+/− mouse islet isolation markedly increased islet viability and adenosine triphosphate content, and attenuated ROS, transcription of c‐Jun N‐terminal kinases, high mobility group box 1, interleukin‐1beta (IL‐1 β), IL‐6, and tumor necrosis factor‐alpha. Supplementation of NecroX‐7 during serum‐deprived culture also protected hIAPP+/− mouse and NHP islets against impaired viability, serum deprivation‐induced ROS, proinflammatory response, and accumulation of toxic IAPP oligomer. Supplementation with NecroX‐7 during isolation or serum‐deprived culture of hIAPP+/− mouse and NHP islets also improved posttransplant glycemia in the recipient streptozotocin‐induced diabetic hIAPP−/− mice and BALB/c‐nu/nu mice, respectively. In conclusion, pretransplant administration of NecroX‐7 during islet isolation and serum‐deprived culture suppressed mitochondrial ROS injury, generation of DAMPs‐induced proinflammatory responses, and accumulation of toxic IAPP oligomers ex vivo, and improved posttransplant glycemia in vivo.

Alleviation of hippocampal necroptosis and neuroinflammation by NecroX-7 treatment after acute seizures

“…In diverse experimental models of degenerative and inflammatory diseases including GVHD, chemotherapy-associated mucositis, atherosclerosis, and myocardial, renal, and hepatic ischemia-reperfusion injuries, NecroX-7 decreased the expression of pro-inflammatory cytokines or damage-associated molecular pattern (DAMPs), i.e., TNFα, IL-1R, IL-6, iNOS, MCP-1, or HMGB1 ( Im et al, 2015 ; Grootaert et al, 2016 ; Jin et al, 2016 ; Lee et al, 2016 ; Hwang et al, 2018 ; Im et al, 2019 ), in line with our findings of NecroX-7-mediated anti-inflammation. Moreover, NecroX-7 controlled inflammatory cellular pathways such as NF-κB, JNK 1/2, and p38 signaling ( Park et al, 2013 ; Chung et al, 2015 ; Grootaert et al, 2016 ; Hwang et al, 2018 ; Kim et al, 2021 ). As the inhibition of cytoplasmic and extracellular redistribution of HMGB1 from the nucleus is considered one of the major modes of action of NecroX-7 ( Park et al, 2012 ; Im et al, 2015 ; Grootaert et al, 2016 ; Jin et al, 2016 ; Lee et al, 2016 ; Hwang et al, 2018 ; Im et al, 2019 ; Kim et al, 2021 ), it is plausible that in SE, blocking extracellular leakage of DAMPs by NecroX-7 may interfere with the initiation of inflammatory pathways and the production of pro-inflammatory cytokines including TNFα, attenuating necroptosis and thereby promoting hippocampal neuroprotection.…”

The effect of hydroxyethyl starch as a cryopreservation agent during freezing of mouse pancreatic islets

“…Mouse islets were isolated from 10- to 12-week-old male C57BL/6 mice as described previously [ 25 ]. Briefly, 0.8 mg/mL collagenase P (Roche, Indianapolis, IN, USA, #45–11213873001) in HBSS was infused into the common bile duct for mouse pancreatic digestion.…”

Mouse models and human islet transplantation sites for intravital imaging

“…This includes CB17.Cg- Prkdc scid Lyst bg-J /Crl (SCID beige) mice, a congenic line that results in defective NK cells, T cells, and B cells through mutations in Pkrdc and Lysbtg ( 79 , 83 , 84 ). Another immunocompromised mouse model occasionally used in human islet transplants is the CAnN.Cg- Foxn1 nu /Crl (BALB/c nu/nu) mouse model ( 85 , 86 ). This mouse lacks a functional thymus, rendering the animals incapable of forming functional T cells.…”