Research progress in ferroptosis pathways and ubiquitination modification of ferroptosis-related molecules / 中国药理学通报

Ferroptosis is an iron-dependent cell death caused by phospholipid peroxidation damage of polyunsaturated fatty acids on cell membranes and involves several pathways, including the iron homeostasis regulatory pathway, the cystine glutamate reverse transporter (system Xc) pathway and the voltage-dependent anion channel (VDAC) pathway. Ferroptosis is involved in the development of several diseases (e. g. myocardial infarction, stroke, cancer and degenerative diseases). The ubiquitination is an important post-translational modification of various protein molecules in the organism. Studies have shown that regulating the ubiquitination of ferroptosis pathway-related molecules can control cellular ferroptosis. Targeting the ubiquitination of ferroptosis pathway-related molecules can effectively promote or inhibit ferroptosis, which is expected to be a new strategy for the treatment of cancer or cardiovascular diseases. In this paper we review the progress of the ferroptosis pathways and the ubiquitination modification of ferroptosis-related molecules.

N-Methyl-(2S, 4R)-trans-4-hydroxy-L-proline, the major bioactive compound from Sideroxylon obtusifolium, attenuates pilocarpine-induced injury in cultured astrocytes

Glial cells have been implicated in temporal lobe epilepsy in humans and in its models. Astrocytes are lost in several brain regions after acute seizures induced by pilocarpine and may suffer hyperplasia at subsequent time points. This study investigated the effect of N-methyl-(2S,4R)-trans-4-hydroxy-L-proline (NMP) on astrocytes exposed to cytotoxic concentrations of pilocarpine. Astrocytes were incubated with pilocarpine (half maximal inhibitory concentration (IC50)=31.86 mM) for 24 h. Afterwards, they were treated with NMP at concentrations ranging from 3.12 to 100 μg/mL for 24 h. Cell viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cytoplasmic reactive oxygen species (ROS) and mitochondrial transmembrane potential (ΔΨm) were analyzed by flow cytometry using 2',7'-dichlorofluorescein diacetate (DCFH-DA) and rhodamine-123 (Rho123), respectively. Expression of glial fibrillary acidic protein (GFAP) and voltage-dependent anion channel-1 (VDAC-1) were measured by western blot. Pilocarpine significantly decreased cell viability and mitochondrial potential and increased ROS concentration significantly by 6.7 times compared to the control. NMP concentrations ≥25 µg/mL protected astrocytes against pilocarpine-induced injury in a concentration-dependent manner. Concomitantly, NMP reduced cytoplasmic ROS accumulation to 27.3, 24.8, and 12.3% in the groups treated with 25, 50, and 100 µg/mL NMP, respectively. NMP also protected mitochondria from pilocarpine-induced depolarization. These effects were associated with improvement of pilocarpine-induced GFAP and VDAC-1 overexpression, which are important biomarkers of astrocyte dysfunction. In conclusion, the improvement of ROS accumulation, VDAC-1 overexpression, and mitochondrial depolarization are possible mechanisms of the NMP protective action on reactive astrocytes.

Study on the mechanism of Wuzi-Yanzong-Wan-medicated serum interfering with the mitochondrial permeability transition pore in the GC-2 cell induced by atractyloside / 中国天然药物

Wuzi-Yanzong-Wan (WZYZW) is a classic prescription for male infertility. Our previous investigation has demonstrated that it can inhibit sperm apoptosis via affecting mitochondria, but the underlying mechanisms are unclear. The purpose of the present study was to explore the actions of WZYZW on mitochondrial permeability transition pore (mPTP) in mouse spermatocyte cell line (GC-2 cells) opened by atractyloside (ATR). At first, WZYZW-medicated serum was prepared from rats following oral administration of WZYZW for 7 days. GC-2 cells were divided into control group, model group, positive group, as well as 5%, 10%, 15% WZYZW-medicated serum group. Cyclosporine A (CsA) was used as a positive control. 50 μmol·L-1 ATR was added after drugs incubation. Cell viability was assessed using CCK-8. Apoptosis was detected using flow cytometry and TUNEL method. The opening of mPTP and mitochondrial membrane potential (MMP) were detected by Calcein AM and JC-1 fluorescent probe respectively. The mRNA and protein levels of voltage-dependent anion channel 1 (VDAC1), cyclophilin D (CypD), adenine nucleotide translocator (ANT), cytochrome C (Cyt C), caspase 3, 9 were detected by RT-PCR (real time quantity PCR) and Western blotting respectively. The results demonstrated that mPTP of GC-2 cells was opened after 24 hours of ATR treatment, resulting in decreased MMP and increased apoptosis. Pre-protection with WZYZ-medicated serum and CsA inhibited the opening of mPTP of GC-2 cells induced by ATR associated with increased MMP and decreased apoptosis. Moreover, the results of RT-qPCR and WB suggested that WZYZW-medicated serum could significantly reduce the mRNA and protein levels of VDAC1 and CypD, Caspase-3, 9 and CytC, as well as a increased ratio of Bcl/Bax. However, ANT was not significantly affected. Therefore, these findings indicated that WZYZW inhibited mitochondrial mediated apoptosis by attenuating the opening of mPTP in GC-2 cells. WZYZW-medicated serum inhibited the expressions of VDAC1 and CypD and increased the expression of Bcl-2, which affected the opening of mPTP and exerted protective and anti-apoptotic effects on GC-2 cell induced by ATR.

Effect of intermittent fasting on the cognitive dysfunction induced by irradiation / 中华放射医学与防护杂志

Objective:To investigate the protective effect of intermittent fasting on radiation-induced cognitive impairment and the possible underlying mechanism.Methods:A total of 36 male 7-week old c57BL/6J mice were divided into Sham-irradiation and ad libitum (Sham-AL) group, irradiation and ad libitum (IR-AL) group, and irradiation add intermittent fasting (IR-IF) group according to the random number table method, with 12 mice in each group. The cognitive function of mice was assessed by novel object recognition task. The expressions of autophagy gene 5 (ATG5), microtubulesas sociated protein light chain II (LC3II), voltage dependent anion channel protein 1 (VDAC1), interleukin-1β (IL-1β), synaptophysin (SYP), synapsin I (SYN-1), and postsynaptic density 95 (PSD95) were tested by Western blot. The location of VDAC1 in mice hippocampus was detected by immunofluorescence.Results:The discrimination index (-22.45 ± 16.76) of IR-AL group was significantly ( t=3.032, P<0.05) lower than that of Sham-AL group (30.02 ± 9.05). Compared to Sham-AL group, IR-AL group had a decreased expressions of autophagy-related proteins (ATG5 and LC3II), mitochondrial marker (VDAC1), inflammatory factors (IL-1β) as well as synapse-associated proteins SYP, SYN-1 and PSD95 ( t=2.49, 2.19, 2.40, 3.47, 2.87, 2.25, 2.17, 2.31, P<0.05). Compared to IR-AL group, IR-IF group had an increased discrimination index (21.22 ± 5.62) and the increased expressions of ATG5, LC3II, VDAC1, IL-1β, SYP, SYN-1, and PSD95 ( t=2.70, 2.88, 2.71, 3.18, 3.18, 3.11, 3.30, 3.35, 2.53, P<0.05). The immunofluorescence assay revealed that VDAC1 was co-expressed with the markers of astrocytes (GFAP) and microglia (IBA-1), but not with neurons (NEUN). Conclusions:Intermittent fasting could greatly improve the cognitive function of irradiated mice possibly by upregulating VDAC1 expression, induce autophagy, and inhibit the release of inflammatory factors and protecting the synapticplasticity in the hippocampus.

Research progress of mitochondrial anion channel as a potential drug target for Alzheimer's disease / 药学学报

Voltage-dependent anion channels (VDACs), which are located at the mitochondrial outer membrane, playing an important role in the regulation of mitochondrial energy metabolism and mitochondria- mediated apoptotic events, are considered as potential targets for tumor therapy. Studies have indicated that neurodegenerative diseases such as Alzheimer's disease (AD) generally lead to mitochondrial dysfunction. During this process, VDAC1, changing in expression, interacting with disease-related molecules, was involved in the occurrence and development of diseases. This review summarizes the characteristics and physiological functions of VDAC1, common important structural units and its role in apoptosis. The focus is on the research progress of VDAC1 in AD, as well as the effects in learning and memory related functions by modulating VDAC1 expression or function.

Effect of high-level spinal cord injury on expression of mitochondrial voltage-dependent anion channel 2 in rat cardiomyocytes / 中华麻醉学杂志

Objective To evaluate the effect of high-level spinal cord injury(SCI)on the expression of mitochondrial voltage-dependent anion channel 2(VDAC2)in rat cardiomyocytes.Methods Forty-eight pathogen-free healthy adult male Sprague-Dawley rats,weighing 200-250 g,were divided into 2 groups(n=24 each)using a random number table:sham operation group(group S)and high-level SCI group(group H).The animals were anesthetized with intraperitoneal chloral hydrate and subjected to SCI using the modified Allen weight-drop method in group H.The spinal cord was only exposed in group S.At 6,12,24 and 48 h after SCI(T1-4),6 rats in each group were randomly selected and sacrificed,and myocardial specimens were collected from the cardiac apex for microscopic examination of the cell morphology(with a transmission electron microscope) and for determination of cell apoptosis(by TUNEL assay),expression of Bax,Bcl-2 and VDAC2 protein and mRNA in cardiomyocytes(by Western blot and real-time polymerase chain reaction,respectively).The apoptosis rate and ratios of Bax/Bcl-2 protein and mRNA were calculated.Results Compared with group S,the apoptosis rate and ratios of Bax/Bcl-2 protein and mRNA were significantly increased at T1-4,the expression of VDAC2 protein and mRNA was significantly down-regulated at T2-4(P<0.05 or 0.01),and the pathologic changes of cardiomyocytes were aggravated in group H.Conclusion The mechanism of myocardial damage is related to down-regulation of mitochondrial VDAC2 expression in cardiomyocytes and promotion of cell apoptosis in rats with high-level SCI.