Protective mitochondrial fission induced by stress-responsive protein GJA1-20k

The Connexin43 gap junction gene GJA1 has one coding exon, but its mRNA undergoes internal translation to generate N-terminal truncated isoforms of Connexin43 with the predominant isoform being only 20 kDa in size (GJA1-20k). Endogenous GJA1-20k protein is not membrane bound and has been found to increase in response to ischemic stress, localize to mitochondria, and mimic ischemic preconditioning protection in the heart. However, it is not known how GJA1-20k benefits mitochondria to provide this protection. Here, using human cells and mice, we identify that GJA1-20k polymerizes actin around mitochondria which induces focal constriction sites. Mitochondrial fission events occur within about 45 s of GJA1-20k recruitment of actin. Interestingly, GJA1-20k mediated fission is independent of canonical Dynamin-Related Protein 1 (DRP1). We find that GJA1-20k-induced smaller mitochondria have decreased reactive oxygen species (ROS) generation and, in hearts, provide potent protection against ischemia-reperfusion injury. The results indicate that stress responsive internally translated GJA1-20k stabilizes polymerized actin filaments to stimulate non-canonical mitochondrial fission which limits ischemic-reperfusion induced myocardial infarction.

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Therapeutic hypothermia cardioprotection via Akt- and nitric oxide-mediated attenuation of mitochondrial oxidants

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00994.2009 ◽

2010 ◽

Vol 298 (6) ◽

pp. H2164-H2173 ◽

Cited By ~ 68

Author(s):

Zuo-Hui Shao ◽

Willard W. Sharp ◽

Kimberly R. Wojcik ◽

Chang-Qing Li ◽

Mei Han ◽

...

Keyword(s):

Nitric Oxide ◽

Therapeutic Hypothermia ◽

Mitochondrial Membrane ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

No Synthase ◽

Ros Generation ◽

Oxygen Species ◽

Lactate Dehydrogenase Release ◽

Hsp27 Phosphorylation

Therapeutic hypothermia (TH) is a promising cardioprotective treatment for cardiac arrest and acute myocardial infarction, but its cytoprotective mechanisms remain unknown. In this study, we developed a murine cardiomyocyte model of ischemia-reperfusion injury to better determine the mechanisms of TH cardioprotection. We hypothesized that TH manipulates Akt, a survival kinase that mediates mitochondrial protection by modulating reactive oxygen species (ROS) and nitric oxide (NO) generation. Cardiomyocytes, isolated from 1- to 2-day-old C57BL6/J mice, were exposed to 90 min simulated ischemia and 3 h reperfusion. For TH, cells were cooled to 32°C during the last 20 min of ischemia and the first hour of reperfusion. Cell viability was evaluated by propidium iodide and lactate dehydrogenase release. ROS production was measured by 6-carboxy-2′,7′-dichlorodihydrofluorescein diacetate and mitochondrial membrane potential (ΔΨm) by 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazoly-carbocyanine iodide (JC-1). Phospho (p)-Akt (Thr308), p-Akt (Ser473), and phosphorylated heat shock protein 27 (p-HSP27) (Ser82) were analyzed by Western blot analysis. TH attenuated reperfusion ROS generation, increased NO, maintained ΔΨm, and decreased cell death [19.3 ± 3.3% ( n = 11) vs. 44.7 ± 2.7% ( n = 10), P < 0.001]. TH also increased p-Akt during ischemia before reperfusion. TH protection and attenuation of ROS were blocked by the inhibition of Akt and NO synthase but not by a cGMP inhibitor. HSP27, a regulator of Akt, also exhibited increased phosphorylation (Ser82) during ischemia with TH. We conclude that TH cardioprotection is mediated by enhanced Akt/HSP27 phosphorylation and enhanced NO generation, resulting in the attenuation of ROS generation and the maintenance of ΔΨm following ischemia-reperfusion.

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Mitochondrial fission and mitophagy are independent mechanisms regulating ischemia/reperfusion injury in primary neurons

Cell Death and Disease ◽

10.1038/s41419-021-03752-2 ◽

2021 ◽

Vol 12 (5) ◽

Author(s):

Anthony R. Anzell ◽

Garrett M. Fogo ◽

Zoya Gurm ◽

Sarita Raghunayakula ◽

Joseph M. Wider ◽

...

Keyword(s):

Cortical Neurons ◽

Ischemia Reperfusion Injury ◽

Mitochondrial Dynamics ◽

Ischemia Reperfusion ◽

Mitochondrial Fission ◽

Conditional Knockout ◽

Mitochondrial Morphology ◽

Primary Neurons ◽

Mitochondrial Fragmentation

AbstractMitochondrial dynamics and mitophagy are constitutive and complex systems that ensure a healthy mitochondrial network through the segregation and subsequent degradation of damaged mitochondria. Disruption of these systems can lead to mitochondrial dysfunction and has been established as a central mechanism of ischemia/reperfusion (I/R) injury. Emerging evidence suggests that mitochondrial dynamics and mitophagy are integrated systems; however, the role of this relationship in the context of I/R injury remains unclear. To investigate this concept, we utilized primary cortical neurons isolated from the novel dual-reporter mitochondrial quality control knockin mice (C57BL/6-Gt(ROSA)26Sortm1(CAG-mCherry/GFP)Ganl/J) with conditional knockout (KO) of Drp1 to investigate changes in mitochondrial dynamics and mitophagic flux during in vitro I/R injury. Mitochondrial dynamics was quantitatively measured in an unbiased manner using a machine learning mitochondrial morphology classification system, which consisted of four different classifications: network, unbranched, swollen, and punctate. Evaluation of mitochondrial morphology and mitophagic flux in primary neurons exposed to oxygen-glucose deprivation (OGD) and reoxygenation (OGD/R) revealed extensive mitochondrial fragmentation and swelling, together with a significant upregulation in mitophagic flux. Furthermore, the primary morphology of mitochondria undergoing mitophagy was classified as punctate. Colocalization using immunofluorescence as well as western blot analysis revealed that the PINK1/Parkin pathway of mitophagy was activated following OGD/R. Conditional KO of Drp1 prevented mitochondrial fragmentation and swelling following OGD/R but did not alter mitophagic flux. These data provide novel evidence that Drp1 plays a causal role in the progression of I/R injury, but mitophagy does not require Drp1-mediated mitochondrial fission.

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Kolaviron attenuates ischemia/reperfusion injury in the stomach of rats

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2017-0138 ◽

2018 ◽

Vol 43 (1) ◽

pp. 30-37 ◽

Cited By ~ 5

Author(s):

Olugbenga Adeola Odukanmi ◽

Adeola Temitope Salami ◽

Onaara Peter Ashaolu ◽

Adeoti Gbemisola Adegoke ◽

Samuel Babafemi Olaleye

Keyword(s):

Acid Secretion ◽

Gastric Acid Secretion ◽

Gastric Acid ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Oxygen Species ◽

Male Adult ◽

Garcinia Kola ◽

Neutrophil Lymphocyte Ratio ◽

Nitric Oxide Level

Kolaviron (KV), an active complex of at least 3 compounds in Garcinia kola seed, which is known for its antioxidant and anti-inflammatory activity, was investigated for its gastro-protective effect in the stomach of rats subjected to ischemia/reperfusion-induced gastric ulceration. Male adult Wistar rats (180–210 g) were randomized into 6 groups (n = 15) as follows: (i) control, (ii) ulcerated untreated (UU), (iii) KV alone (KVA), (iv) KV + ulcer (KVU), (v) ulcer + KV (UKV), and (vi) ulcer + omeprazole (20 mg/kg). Ulcer was induced through ischemia/reperfusion method after 2 weeks of daily oral KV (100 mg/kg). Rats were weighed daily, and gastric acid secretion, ulcer scores, hematological, biochemical, and histological variables were assessed 1 h after induction at 3 and 7 days post-ulceration. Body weight decreased in KVA (179.1 ± 1.6 g), and KVU (170.1 ± 2.2 g) compared with UU (199.0 ± 1.4 g). Gastric acid secretion decreased significantly in KVU after 1 h and 3 days post-ulceration (0.27 ± 0.03 mEq/L; 0.49 ± 0.02 mEq/L) compared with UU (0.60 ± 0.06 mEq/L; 0.85 ± 0.29 mEq/L), respectively. There was significant reduction in neutrophil/lymphocyte ratio of KVA (0.29 ± 0.06) and KVU (0.35 ± 0.02) compared with UU (0.54 ± 0.04). Malondialdehyde level decreased significantly with concomitant increase in anti-oxidative activities and nitric oxide level in the KV treated groups (KVA, KVU, UKV) compared with UU. In conclusion, treatment with KV protects the stomach by reducing gastric acid secretion, promoting antioxidant activity and suppressing action of reactive oxygen species.

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Mitochondrial fission in endothelial cells after simulated ischemia/reperfusion: role of nitric oxide and reactive oxygen species

Free Radical Biology and Medicine ◽

10.1016/j.freeradbiomed.2011.10.491 ◽

2012 ◽

Vol 52 (2) ◽

pp. 348-356 ◽

Cited By ~ 64

Author(s):

Randy J. Giedt ◽

Changjun Yang ◽

Jay L. Zweier ◽

Anastasios Matzavinos ◽

B. Rita Alevriadou

Keyword(s):

Nitric Oxide ◽

Reactive Oxygen Species ◽

Endothelial Cells ◽

Ischemia Reperfusion ◽

Mitochondrial Fission ◽

Reactive Oxygen ◽

Oxygen Species ◽

Simulated Ischemia

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Mesenchymal Stromal Cells Derived Extracellular Vesicles Ameliorate Acute Renal Ischemia Reperfusion Injury by Inhibition of Mitochondrial Fission through miR-30

Stem Cells International ◽

10.1155/2016/2093940 ◽

2016 ◽

Vol 2016 ◽

pp. 1-12 ◽

Cited By ~ 52

Author(s):

Di Gu ◽

Xiangyu Zou ◽

Guanqun Ju ◽

Guangyuan Zhang ◽

Erdun Bao ◽

...

Keyword(s):

Reperfusion Injury ◽

Extracellular Vesicles ◽

Mesenchymal Stromal Cells ◽

Stromal Cells ◽

Ischemia Reperfusion Injury ◽

Mitochondrial Dynamics ◽

Ischemia Reperfusion ◽

Mitochondrial Fission ◽

Apoptosis Pathway ◽

Acute Renal Ischemia

Background. The immoderation of mitochondrial fission is one of the main contributors in ischemia reperfusion injury (IRI) and mesenchymal stromal cells (MSCs) derived extracellular vesicles have been regarded as a potential therapy method. Here, we hypothesized that extracellular vesicles (EVs) derived from human Wharton Jelly mesenchymal stromal cells (hWJMSCs) ameliorate acute renal IRI by inhibiting mitochondrial fission through miR-30b/c/d.Methods. EVs isolated from the condition medium of MCS were injected intravenously in rats immediately after monolateral nephrectomy and renal pedicle occlusion for 45 minutes. Animals were sacrificed at 24 h after reperfusion and samples were collected. MitoTracker Red staining was used to see the morphology of the mitochondria. The expression of DRP1 was measured by western blot. miR-30 in EVs and rat tubular epithelial cells was assessed by qRT-PCR. Apoptosis pathway was identified by immunostaining.Results. We found that the expression of miR-30 in injured kidney tissues was declined and mitochondrial dynamics turned to fission. But they were both restored in EVs group in parallel with reduced cell apoptosis. What is more, when the miR-30 antagomirs were used to reduce the miRNA levels, all the related effects of EVs reduced remarkably.Conclusion. A single administration of hWJMSC-EVs could protect the kidney from IRI by inhibition of mitochondrial fission via miR-30.

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c-Jun DNAzymes Inhibit Myocardial Inflammation, ROS Generation, Infarct Size, and Improve Cardiac Function After Ischemia-Reperfusion Injury

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvbaha.109.189753 ◽

2009 ◽

Vol 29 (11) ◽

pp. 1836-1842 ◽

Cited By ~ 31

Author(s):

Xiao Luo ◽

Hong Cai ◽

Jun Ni ◽

Ravinay Bhindi ◽

Harry C. Lowe ◽

...

Keyword(s):

Cardiac Function ◽

Infarct Size ◽

Reperfusion Injury ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Ros Generation ◽

Myocardial Inflammation

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Abstract P311: Blocking Succinate Release Enhances Mitochondrial Reactive Oxygen Species Generation And Worsens Ischemia-reperfusion Injury

Circulation Research ◽

10.1161/res.129.suppl_1.p311 ◽

2021 ◽

Vol 129 (Suppl_1) ◽

Author(s):

Alexander S Milliken ◽

Sergiy M Nadtochiy ◽

Paul S Brookes

Keyword(s):

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Reactive Oxygen Species Generation ◽

Ros Generation ◽

Ros Production ◽

Succinate Oxidation ◽

Fluorescence Measurements ◽

Mitochondrial Ros ◽

The Impact ◽

Infarction Heart

Succinate is a metabolite that plays a central role in ischemia-reperfusion (IR) injury,which is relevant to myocardial infarction (heart attack) and stroke. Succinateaccumulates during ischemia and is rapidly consumed at reperfusion driving reactiveoxygen species (ROS) generation at complex-I (Cx-I) and III of the mitochondrial electrontransport chain. This ROS production triggers cell-death, leading to tissue necrosis.Although succinate oxidation has been extensively studied and exploited as a noveltherapeutic target, only 1/3 of the succinate accumulated in ischemia is oxidized atreperfusion, with the remaining 2/3 being released from the cell via monocarboxylatetransporter 1 (MCT1). Extracellular succinate is thought to be pro-inflammatory, and ithas been proposed that preventing succinate release may be therapeutically beneficial.To determine the impact of preventing succinate release on IR injury, we comparedfunctional recovery (i.e. rate x pressure product, RPP) and infarction (i.e. tissue necrosis)of Langendorff perfused mouse hearts treated with an MCT1 inhibitor, AR-C155858,versus vehicle control. This revealed that succinate retention worsens IR injury (i.e.increased infarction and decreased functional recovery) likely due to increased ROS. Totest this hypothesis, we utilized a Langendorff apparatus positioned within aspectrofluorimeter, which permits real-time fluorescence measurements in beatingmouse hearts. Using the mitochondria targeted superoxide probe, MitoSOX red tomeasure ROS production at reperfusion + AR-C155858, demonstrated that succinateretention leads to enhanced mitochondrial ROS generation at the onset of reperfusion.Overall, these results suggest that inhibiting succinate release in the context of IR injurymay not be a viable therapeutic approach, regardless of any downstream anti-inflammatory effects.

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LncRNA PVT1 Mediated by ZFP36L2 Regulates Myocardial Ischemia/Reperfusion Injury and Attenuates Mitochondrial Fusion and Fission via Activating miR-21-5p/MARCH5 Axis

10.21203/rs.3.rs-108063/v1 ◽

2020 ◽

Author(s):

Weifeng Huang ◽

Qin Tan ◽

Yong Guo ◽

Yongmei Cao ◽

Jiawei Shang ◽

...

Keyword(s):

Zinc Finger Protein ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Mitochondrial Fission ◽

Tumor Biology ◽

Luciferase Reporter ◽

Mitochondrial Morphology ◽

Mrna Levels

Abstract BackgroundAmong several leading cardiovascular disorders, ischemia-reperfusion (I/R) injury causes severe manifestations including acute heart failure, inflammation, and systemic dysfunction. Recently, there has been increasing evidence suggesting that alterations in mitochondrial morphology play a role in the prognoses of cardiac disorders. Long non-coding RNAs (lncRNAs) form major regulatory networks to modify gene transcription and translation. While several roles of lncRNAs have been explored in cancer and tumor biology, their implications on mitochondrial morphology and functions remain to be elucidated. MethodsThe functional roles of ZFP36L2 and lncRNA PVT1 were determined by a series of cardiomyocyte hypoxia/ reoxygenation (H/R) in vitro and myocardial I/R injury in vivo experiments. Quantitative Reverse transcription-polymerase chain reaction (qRT-PCR) and western blot analysis were used to detect the mRNA levels of ZFP36L2 and mitochondrial fission and fusion markers in the myocardial tissues and cardiomyocyte. Cardiac function was determined by immunohistochemistry, H&E, Masson’s staining and echocardiogram. Ultrastructural analysis of mitochondrial fission was performed using transmission electron microscopy (TEM). The mechanistic model of PVT1 with ZFP36L2 and miR-21-5p with MARCH5 was detected by subcellular fraction, RNA pull down, FISH, and luciferase reporter assays.ResultsIn this study, we report a novel regulatory axis involving lncRNA PVT1, microRNA miR-21-5p, and E3 ubiquitin ligase MARCH5, which alters mitochondrial morphology during myocardial I/R injury. Using an in vivo I/R injury mouse model and in vitro cardiomyocyte H/R model, we observed that zinc finger protein ZFP36L2 directly associated with PVT1 and altered mitochondrial fission and fusion. PVT1 also interacted with miR-21-5p and suppressed its expression and activity. Furthermore, we identified MARCH5 as a modifier of miR-21-5p, and expression of MARCH5 and its effect on mitochondrial fission and fusion were directly proportional to PVT1 expression during H/R injury. ConclusionsOur findings demonstrated that manipulation of PVT1-miR-21-5p-MARCH5-mediated mitochondrial fission and fusion via ZFP36L2 may be a novel therapeutic approach to regulate myocardial I/R injury.

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Cannabinoid CB1 receptor agonist ACEA alleviates brain ischemia/reperfusion injury via CB1–Drp1 pathway

Cell Death Discovery ◽

10.1038/s41420-020-00338-3 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Shuai Yang ◽

Bin Hu ◽

Zongming Wang ◽

Changming Zhang ◽

Haosen Jiao ◽

...

Keyword(s):

Reperfusion Injury ◽

Brain Ischemia ◽

Receptor Agonist ◽

Ischemia Reperfusion Injury ◽

Infarct Volume ◽

Ischemia Reperfusion ◽

Mitochondrial Fission ◽

Cb1 Receptor ◽

Cannabinoid Cb1 Receptor ◽

Neuroprotective Effects

Abstract Activation of the cannabinoid CB1 receptor induces neuroprotection against brain ischemia/reperfusion injury (IRI); however, the mechanism is still unknown. In this study, we used oxygen-glucose deprivation/reoxygenation (OGD/R)-induced injury in neuronal cells and middle cerebral artery occlusion (MCAO)-induced brain IRI in rats to mimic ischemic brain injury, and hypothesized that the CB1 receptor agonist arachidonyl-2-chloroethylamide (ACEA) would protect ischemic neurons by inhibiting mitochondrial fission via dynamin-related protein 1 (Drp1). We found that OGD/R injury reduced cell viability and mitochondrial function, increased lactate dehydrogenase (LDH) release, and increased cell apoptosis, and mitochondrial fission. Notably, ACEA significantly abolished the OGD/R-induced neuronal injuries described above. Similarly, ACEA significantly reversed MCAO-induced increases in brain infarct volume, neuronal apoptosis and mitochondrial fission, leading to the recovery of neurological functions. The neuroprotective effects of ACEA were obviously blocked by coadministration of the CB1 receptor antagonist AM251 or by the upregulation of Drp1 expression, indicating that ACEA alleviates brain IRI via the CB1–Drp1 pathway. Our findings suggest that the CB1 receptor links aberrant mitochondrial fission to brain IRI, providing a new therapeutic target for brain IRI treatment.

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