Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter

Abstract

Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 μM of each tetracycline-derived compound 20 min prior to exposure to 500 μM iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs-Ringer-Hepes buffer (KRH) at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca2+ uptake was measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometery was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca2+ uptake and suppressed the Ca2+-induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca2+ uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU.

Joint toxicity of fluoroquinolone and tetracycline antibiotics to zebrafish (<i>Danio rerio</i>) based on biochemical biomarkers and histopathological observation

“…Recent observations have also shown that intracellular H 2 O 2 is markedly increased after exposure to 10 μg/mL ofloxacin for 12 hr in monolayer cultured chondrocytes (Li et al, 2010). Schwartz and co-workers found that minocycline and doxycycline could depolarize mitochondria at a high concentration and inhibit matrix metalloprotease (Schwartz et al, 2013). Zhang and coworkers reported that the 96-hr LC 50 values of tetracycline were 406.0 and 322.8 mg/L in zebrafish and carp, respectively .…”

Effect of Doxycycline on Aseptic Reperfusion Injury in Ovarian Torsion

“…It reduces apoptosis by decreasing mitochondrial Ca 2+ uptake and mitochondrial permeability transition (20). It also reduces production of reactive oxygen radicals and induces the antioxidant and cytoprotective pathways such as nuclear factor erythroid 2-related factor 2 (Nrf2) (21).…”

Minocycline decreases blood glucose and triglyceride levels and reverses histological and immunohisto-chemical alterations in pancreas, liver and kidney of alloxan-induced diabetic rats

“…Evidences (Czerny et al, 2012;Schwartz et al, 2013) demonstrated that minocycline decreased liver injury and oxidative stress, after mice hemorrhage and resuscitation, and mitigated the damage caused by ischemia/reperfusion injury in cultured rat hepatocytes. As discussed earlier, a chronic low-grade inflammation is known to be present not only in type 2, but also in type 1 diabetes (Odegaard and Chawla, 2012), and contributes to insulin resistance.…”