Novel mitochondrial transition pore inhibitor N‐methyl‐4‐isoleucine cyclosporin is a new therapeutic option in acute pancreatitis

Abstract

Key points •Bile acids, ethanol and fatty acids affect pancreatic ductal fluid and bicarbonate secretion via mitochondrial damage, ATP depletion and calcium overload. •Pancreatitis‐inducing factors open the membrane transition pore (mPTP) channel via cyclophilin D activation in acinar cells, causing calcium overload and cell death; genetic or pharmacological inhibition of mPTP improves the outcome of acute pancreatitis in animal models. •Here we show that genetic and pharmacological inhibition of mPTP protects mitochondrial homeostasis and cell function evoked by pancreatitis‐inducing factors in pancreatic ductal cells. •The results also show that the novel cyclosporin A derivative NIM811 protects mitochondrial function in acinar and ductal cells, and it preserves bicarbonate transport mechanisms in pancreatic ductal cells. •We found that NIM811 is highly effective in different experimental pancreatitis models and has no side‐effects. NIM811 is a highly suitable compound to be tested in clinical trials. Abstract Mitochondrial dysfunction plays a crucial role in the development of acute pancreatitis (AP); however, no compound is currently available with clinically acceptable effectiveness and safety. In this study, we investigated the effects of a novel mitochondrial transition pore inhibitor, N‐methyl‐4‐isoleucine cyclosporin (NIM811), in AP. Pancreatic ductal and acinar cells were isolated by enzymatic digestion from Bl/6 mice. In vitro measurements were performed by confocal microscopy and microfluorometry. Preventative effects of pharmacological [cylosporin A (2 µm), NIM811 (2 µm)] or genetic (Ppif−/−/Cyp D KO) inhibition of the mitochondrial transition pore (mPTP) during the administration of either bile acids (BA) or ethanol + fatty acids (EtOH+FA) were examined. Toxicity of mPTP inhibition was investigated by detecting apoptosis and necrosis. In vivo effects of the most promising compound, NIM811 (5 or 10 mg kg−1 per os), were checked in three different AP models induced by either caerulein (10 × 50 µg kg−1), EtOH+FA (1.75 g kg−1 ethanol and 750 mg kg−1 palmitic acid) or 4% taurocholic acid (2 ml kg−1). Both genetic and pharmacological inhibition of Cyp D significantly prevented the toxic effects of BA and EtOH+FA by restoring mitochondrial membrane potential (Δψ) and preventing the loss of mitochondrial mass. In vivo experiments revealed that per os administration of NIM811 has a protective effect in AP by reducing oedema, necrosis, leukocyte infiltration and serum amylase level in AP models. Administration of NIM811 had no toxic effects. The novel mitochondrial transition pore inhibitor NIM811 thus seems to be an exceptionally good candidate compound for clinical trials in AP.

Knockout of the Mitochondrial Calcium Uniporter Strongly Suppresses Stimulus-Metabolism Coupling in Pancreatic Acinar Cells but Does Not Reduce Severity of Experimental Acute Pancreatitis

“…Genetic inhibition of MPTP by global knock-out of cyclophilin D, which is a regulator of MPTP complex [ 79 , 80 ], was shown to protect animals against AP in all three models used in the present study [ 6 ]. Similar results were obtained with pharmacological cyclophilin D/MPTP inhibitors [ 81 ]. Mitochondrial Ca 2+ entry is a prominent inducer of MPT in the acinar cells [ 37 , 38 ].…”

“…We therefore hypothesized that ablation of the MCU (primary mediator of mitochondrial Ca 2+ entry) would reduce the severity of AP. Our finding that MCU knock-out does not protect against AP in vivo was unexpected but highlights the importance of mitochondrial function in reducing the severity of AP, as achieved by MPTP inhibition [ 6 , 81 ]. It should be noted that our results are similar to the observed lack of protection of cardiac tissue against ischemia-reperfusion in MCU −/− mice [ 53 ] and MCU dominant negative mice [ 82 ].…”

Multifactorial Scores and Biomarkers of Prognosis of Acute Pancreatitis: Applications to Research and Practice

“…However, there is recent evidence that not only the acinar but ductal cell is also involved in the initial events of pancreatic damage and in the development of the inflammatory process [17]. The main function of the pancreatic duct is the bicarbonate and fluid secretion, which can be influenced by alcohol, fatty acids, and bile acids [16,18,19]. The changes in either fluid or bicarbonate secretion are related to changes in cystic fibrosis transmembrane conductance regulator (CFTR) function and expression [17].…”

“…Systemic Inflammatory Response Syndrome (SIRS) is a result of all these events, which may advance to multiorgan disfunction, as well as infection of pancreatic necrosis and sepsis. CFTR: Cystic Fibrosis Transmembrane Conductance Regulator; PMN: polymorphonuclear; SIRS: Systemic Inflammatory Response Syndrome; MODS: Multiple Organ Dysfunction Syndrome [6,10,[16][17][18][19][20][21][22][23].…”

Drug discovery and formulation development for acute pancreatitis

“…Mitochondrial permeability transition pore inhibition provides a promising approach to suppress mitochondrial dysfunction, which was beneficial for acute pancreatitis treatment. Mitochondrial transition pore inhibitor, 3,5-seco-4-nor-cholestan-5-one oxime-3-ol (TRO40303) and N-methyl-4-isoleucine cyclosporin (NIM811) were proved to be beneficial to overcoming acute pancreatitis by inhibiting mitochondrial dysfunction and reducing cell necrosis (Javed et al., 2018 ; Tóth et al., 2019 ). Thus, inhibiting mitochondrial transition pore might provide new sight for acute pancreatitis treatment.…”