bims-tofagi 2023-09-10 papers

on Mitophagy

Issue of 2023–09–10
sixteen papers selected by
Michele Frison, University of Cambridge and Aitor Martínez Zarate, Euskal Herriko Unibertsitatea

Yi Mai granules improve energy supply of endothelial cells in atherosclerosis rat model via miRNA-125a-5p regulating mitochondrial autophagy through Pink1-Mfn2-Parkin pathway.
ROS-mediated mitophagy and necroptosis regulate osteocytes death caused by TCP particles in MLO-Y4 cells.
SGLT2 inhibitor empagliflozin alleviates cardiac remodeling and contractile anomalies in a FUNDC1-dependent manner in experimental Parkinson's disease.
Nanomicelle curcumin-induced testicular toxicity: Implications for altered mitochondrial biogenesis and mitophagy following redox imbalance.
Damaged mitochondria recruit the effector NEMO to activate NF-κB signaling.
Sulforaphane ameliorated podocyte injury according to regulation of the Nrf2/PINK1 pathway for mitophagy in diabetic kidney disease.
New insights into brain injury in chickens induced by bisphenol A and selenium deficiency-Mitochondrial reactive oxygen species and mitophagy-apoptosis crosstalk homeostasis.
Activation of ULK1 to trigger FUNDC1-mediated mitophagy in heart failure: Effect of Ginsenoside Rg3 intervention.
New insights into Microalgal astaxanthin's effect on Lambda-cyhalothrin-induced lymphocytes immunotoxicity in Cyprinus carpio: Involving miRNA-194-5p-FoxO1-mediated-mitophagy and pyroptosis.
MitoQ combats tumor cell progression in Ehrlich ascites carcinoma mice: A crosstalk between mitochondrial oxidative status, mitophagy, and NF-κB signaling.
UCHL1 alleviates apoptosis in chondrocytes via upregulation of HIF‑1α‑mediated mitophagy.
Fighting Against Drug-resistant Tumor by The Induction of Excessive Mitophagy with Transferrin Nanomedicine.
Effects of DJ‑1 on apoptosis and mitophagy of glomerular podocytes.
Exploring a new mechanism between lactate and VSMC calcification: PARP1/POLG/UCP2 signaling pathway and imbalance of mitochondrial homeostasis.
BCL2L13 promotes mitophagy through DNM1L-mediated mitochondrial fission in glioblastoma.
Mammalian autophagosomes form from finger-like phagophores.

J Ethnopharmacol. 2023 Sep 05. pii: S0378-8741(23)00982-0. [Epub ahead of print] 117114

Yi Mai granules improve energy supply of endothelial cells in atherosclerosis rat model via miRNA-125a-5p regulating mitochondrial autophagy through Pink1-Mfn2-Parkin pathway.

De Zhao Kong, Peng Sun, Yi Lu, Ye Yang, Dong Yu Min, Si Cheng Zheng, Yi Yang, Zhe Zhang, Guan Lin Yang, Jun Wen Jiang.

   ETHNOPHARMACOLOGICAL RELEVANCE: Yi Mai granules (YMG) consists of two classic Chinese medicine formulas used to treat cardiovascular disease for centuries. The Pink1-Mfn2-Parkin pathway, a well-recognized mechanism that mediates mitochondrial autophagy, plays a big part in mitochondrial quality control and the maintenance of heart function. However, the effects of YMG on endothelial dysfunction and mitochondrial autophagy remain unknown.
AIM OF THE STUDY: Here, we focused on the therapeutic effects of YMG in improving mitochondrial autophagy and the mechanism of YMG against cardiovascular disease.
MATERIALS AND METHODS: In this study, rats were fed high-fat diet (HFD) for 21 weeks and were given high, medium, and low doses of YMG in stomach. The open field test was used to evaluate the rats' behavior. Atherosclerotic plaques, blood lipids, and cytokine levels were measured. Mitochondrial autophagy changes were observed by Transmission electron microscope (TEM). Human umbilical vein endothelial cells (HUVECs) were injured by angiotensinⅡ(AngⅡ) and were given high, medium, and low doses of YMG medicated serum in cell culture medium. Pink1-Mfn2-Parkin expression and miRNA 125a-5p expression were measured by RT-PCR and Western blot.
RESULTS: We demonstrated that the atherosclerosis model group tended to exhibit reduced vitality behaviors. We proved that the atherosclerosis model group showed obvious atherosclerotic plaques, endothelial cells destruction, and high level of blood lipid and cytokines (including hs-CRP, ET). Mitochondria were reduced, and mitophagy was inhibited in aortic cells of the model group. MiRNA-125a-5p was up-regulated; at the same time, Pink1-Mfn2-Parkin-mediated mitochondrial autophagy was prevented. We also proved that AngⅡinjured HUVEC showed obviously low mRNA levels of Pink1, Mfn2, and Parkin. Interestingly, we found that miRNA-125a-5p was significantly down regulated in Ang II-induced HUVECs. In addition, YMG reversed the low expression of Pink1, Mfn2, and Parkin induced by AngⅡand miRNA-125a-5p mimic.
CONCLUSION: Our finding indicated that Pink1-Mfn2-Parkin-mediated mitochondrial autophagy plays a crucial role in alleviating atherosclerosis. YMG alleviated atherosclerosis by potentially activating mitochondrial autophagy may via miRNA-125a-5p, regulating Pink1-Mfn2-Parkin pathway, and regulating proinflammatory factors, vasoconstriction cytokine, and blood lipids.

Keywords:  Atherosclerosis; Mitochondria autophagy; Pink1-Mfn2-parkin; Yi mai granules (YMG); miRNA125a

DOI:  https://doi.org/10.1016/j.jep.2023.117114
Toxicology. 2023 Sep 05. pii: S0300-483X(23)00214-7. [Epub ahead of print] 153627

ROS-mediated mitophagy and necroptosis regulate osteocytes death caused by TCP particles in MLO-Y4 cells.

Pei Yang, Bingbing Xu, Ruirong Zhu, Tao Zhang, Zihan Wang, Qiao Lin, Ming Yan, Zhangsen Yu, Hongjiao Mao, Yun Zhang.

  Our previous data have revealed TCP particles caused cell death of osteocytes, comprising over 95% of all bone cells, which contribute to periprosthetic osteolysis, joint loosening and implant failure, but its mechanisms are not fully understood. Here, we reported that TCP particles inhibited cell viability of osteocytes MLO-Y4, and caused cell death. TCP particles caused mitochondrial impairment and increased expressions of LC-3 II, Parkin and PINK 1, accompanied by the elevation of autophagy flux and intracellular acidic components, the accumulation of LC-3II, PINK1 and Parkin in damaged mitochondria, and p62 reduction. The increased LC-3II expression and cell death extent were significantly enhanced by the autophagy inhibitor Baf A1, compared with Baf A1 (or TCP particles) alone, indicating that TCP particles increase autophagic flux and lead to cell even death of MLO-Y4 cells, closely associated with mitophagy. Furthermore, TCP particles induced propidium iodide (PI) uptake and the phosphorylation of RIP1, RIP3 and MLKL, thereby increasing necroptosis in MLO-Y4 cells. The pro-necroptotic effect was alleviated by the RIP1 inhibitor Nec-1 or the MLKL inhibitor NSA. Additionally, TCP particles promoted the production of intracellular reactive oxygen species (ROS) and mitochondrial ROS (mtROS), and increased TXNIP expression, but decreased protein levels of TRX1, Nrf2, HO-1 and NQO1, leading to oxidative stress. The ROS scavenger NAC remarkably reversed mitophagy and necroptosis caused by TCP particles, suggesting that ROS is responsible for mitophagy and necroptosis. Collectively, ROS-mediated mitophagy and necroptosis regulate osteocytes death caused by TCP particles in MLO-Y4 cells, which enhances osteoclastogenesis and periprosthetic osteolysis.

Keywords:  TCP particles; mitophagy; necroptosis; osteocytes; reactive oxygen species

DOI:  https://doi.org/10.1016/j.tox.2023.153627
Acta Pharmacol Sin. 2023 Sep 07.

SGLT2 inhibitor empagliflozin alleviates cardiac remodeling and contractile anomalies in a FUNDC1-dependent manner in experimental Parkinson's disease.

Wei Yu, Lin Wang, Wei-Ying Ren, Hai-Xia Xu, Ne N Wu, Dong-Hui Yu, Russel J Reiter, Wen-Liang Zha, Qing-Dong Guo, Jun Ren.

  Recent evidence shows a close link between Parkinson's disease (PD) and cardiac dysfunction with limited treatment options. Mitophagy plays a crucial role in the control of mitochondrial quantity, metabolic reprogramming and cell differentiation. Mutation of the mitophagy protein Parkin is directly associated with the onset of PD. Parkin-independent receptor-mediated mitophagy is also documented such as BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) and FUN14 domain containing 1 (FUNDC1) for receptor-mediated mitophagy. In this study we investigated cardiac function and mitophagy including FUNDC1 in PD patients and mouse models, and evaluated the therapeutic potential of a SGLT2 inhibitor empagliflozin. MPTP-induced PD model was established. PD patients and MPTP mice not only displayed pronounced motor defects, but also low plasma FUNDC1 levels, as well as cardiac ultrastructural and geometric anomalies (cardiac atrophy, interstitial fibrosis), functional anomalies (reduced E/A ratio, fractional shortening, ejection fraction, cardiomyocyte contraction) and mitochondrial injury (ultrastructural damage, UCP2, PGC1α, elevated mitochondrial Ca2+ uptake proteins MCU and VDAC1, and mitochondrial apoptotic protein calpain), dampened autophagy, FUNDC1 mitophagy and apoptosis. By Gene set enrichment analysis (GSEA), we found overtly altered glucose transmembrane transport in the midbrains of MPTP-treated mice. Intriguingly, administration of SGLT2 inhibitor empagliflozin (10 mg/kg, i.p., twice per week for 2 weeks) in MPTP-treated mice significantly ameliorated myocardial anomalies (with exception of VDAC1), but did not reconcile the motor defects or plasma FUNDC1. FUNDC1 global knockout (FUNDC1-/- mice) did not elicit any phenotype on cardiac geometry or function in the absence or presence of MPTP insult, but it nullified empagliflozin-caused cardioprotection against MPTP-induced cardiac anomalies including remodeling (atrophy and fibrosis), contractile dysfunction, Ca2+ homeostasis, mitochondrial (including MCU, mitochondrial Ca2+ overload, calpain, PARP1) and apoptotic anomalies. In neonatal and adult cardiomyocytes, treatment with PD neurotoxin preformed fibrils of α-synuclein (PFF) caused cytochrome c release and cardiomyocyte mechanical defects. These effects were mitigated by empagliflozin (10 μM) or MCU inhibitor Ru360 (10 μM). MCU activator kaempferol (10 μM) or calpain activator dibucaine (500 μM) nullified the empagliflozin-induced beneficial effects. These results suggest that empagliflozin protects against PD-induced cardiac anomalies, likely through FUNDC1-mediated regulation of mitochondrial integrity.

Keywords:  FUNDC1; MCU; Parkinson’s disease; cardiac dysfunction; empagliflozin; mitochondria

DOI:  https://doi.org/10.1038/s41401-023-01144-0
Biomed Pharmacother. 2023 Sep 01. pii: S0753-3322(23)01154-X. [Epub ahead of print]166 115363

Nanomicelle curcumin-induced testicular toxicity: Implications for altered mitochondrial biogenesis and mitophagy following redox imbalance.

Zafer Yönden, Farzaneh Bonyadi, Yavar Yousefi, Amin Daemi, Seyyedeh Touran Hosseini, Sana Moshari.

  The purpose of this study was to examine the effects of nano-micelle curcumin (NMC)-induced redox imbalance on mitochondrial biogenesis and mitophagy. For this purpose, 24 mature male Wistar rats were divided into control and NMC-received groups (7.5, 15, and 30 mg/kg) groups. After 48 days, the Nrf1, Nrf2, and SOD (Cu/Zn) expression levels, as well as GSH/GSSG, NADP+ /NADPH relative balances (elements involved in redox homeostasis) were analyzed. Moreover, to explore the effect of NMC on mitochondrial biogenesis, the expression levels of Mfn1, Mfn2, OPA1, Fis1, and Drp1 were investigated. Finally, the expression levels of Parkin/PARK and PINK (genes involved in mitochondrial quality control), as well as LC3-I/II (mitophagy marker), were analyzed. Observations showed that NMC, dose-dependently, altered GSH/GSSG, NADP+ /NADPH relative balances, suppressed SOD expression and diminished its biochemical level, and repressed Nrf1 and Nrf2 expression levels. Moreover, it could change the Mfn1, Mfn2, OPA1, Fis1, and Drp1 expression pattern and stimulate the Parkin/PARK and PINK as well as LC3-I/II expression levels, dose-dependently. In conclusion, chronic and high-dose NMC is able to suppress the redox capacity by down-regulating the Nrf1 and Nrf2 expression. Finally, at high-dose levels, it is able to trigger mitophagy signaling in the testicles.

Keywords:  Biogenesis; Mitochondria; Mitophagy; Nano-micelle curcumin; Oxidative stress

DOI:  https://doi.org/10.1016/j.biopha.2023.115363
Mol Cell. 2023 Sep 07. pii: S1097-2765(23)00641-X. [Epub ahead of print]83(17): 3188-3204.e7

Damaged mitochondria recruit the effector NEMO to activate NF-κB signaling.

Olivia Harding, Elisabeth Holzer, Julia F Riley, Sascha Martens, Erika L F Holzbaur.

  Failure to clear damaged mitochondria via mitophagy disrupts physiological function and may initiate damage signaling via inflammatory cascades, although how these pathways intersect remains unclear. We discovered that nuclear factor kappa B (NF-κB) essential regulator NF-κB effector molecule (NEMO) is recruited to damaged mitochondria in a Parkin-dependent manner in a time course similar to recruitment of the structurally related mitophagy adaptor, optineurin (OPTN). Upon recruitment, NEMO partitions into phase-separated condensates distinct from OPTN but colocalizing with p62/SQSTM1. NEMO recruitment, in turn, recruits the active catalytic inhibitor of kappa B kinase (IKK) component phospho-IKKβ, initiating NF-κB signaling and the upregulation of inflammatory cytokines. Consistent with a potential neuroinflammatory role, NEMO is recruited to mitochondria in primary astrocytes upon oxidative stress. These findings suggest that damaged, ubiquitinated mitochondria serve as an intracellular platform to initiate innate immune signaling, promoting the formation of activated IKK complexes sufficient to activate NF-κB signaling. We propose that mitophagy and NF-κB signaling are initiated as parallel pathways in response to mitochondrial stress.

Keywords:  ALS; NEMO; NF-κB; NF-κB effector molecule; Parkin; Parkinson’s disease; SQSTM1/p62; amyotrophic lateral sclerosis; cell stress; innate immunity; mitophagy; neurodegeneration; neuroinflammation; optineurin nuclear factor kappa B; phase separation; ubiquitin

DOI:  https://doi.org/10.1016/j.molcel.2023.08.005
Eur J Pharmacol. 2023 Sep 01. pii: S0014-2999(23)00554-X. [Epub ahead of print] 176042

Sulforaphane ameliorated podocyte injury according to regulation of the Nrf2/PINK1 pathway for mitophagy in diabetic kidney disease.

Yanyan Wang, Yanan Xu, Qingzhu Wang, Feng Guo, Yi Song, Xunjie Fan, Mingwei Shao, Duo Chen, Wei Zhang, Guijun Qin.

  Mitophagy, a mechanism of self-protection against oxidative stress, plays a critical role in podocyte injury caused by diabetic kidney disease (DKD). Sulforaphane (SFN), an isothiocyanate compound, is a potent antioxidant that affords protection against diabetes mellitus-mediated podocyte injury. However, its role and underlying mechanism in DKD especially in diabetic podocytopathy is not clearly defined. In the current study, we demonstrated SFN remarkably activated mitophagy in podocytes, restored urine albumin to creatinine ration, and prevented the glomerular hypertrophy and extensive foot process fusion in diabetic mice. Simultaneously, nephroprotective effects of SFN on kidney injury were abolished in podocyte-specific Nuclear factor erythroid 2-related factor 2 (Nrf2) conditional knockout mouse (cKO), indicating that SFN alleviating DM-induced podocyte injury dependent on Nrf2. In vitro study, supplement with SFN augmented the expression of PTEN induced kinase 1(PINK1) and mediated the activation of mitophagy in podocytes treated with high glucose. Further study revealed that SFN treatment enabled Nrf2 translocate into nuclear and bind to the specific site of PINK1 promoter, ultimately reinforcing the transcription of PINK1. Moreover, SFN failed to confer protection to podocytes treated with high glucose in presence of PINK1 knockdown. On the contrary, exogenous overexpression of PINK1 reversed mitochondrial abnormalities in Nrf2 cKO diabetic mice. In conclusion, SFN alleviated podocyte injury in DKD through activating Nrf2/PINK1 signaling pathway and balancing mitophagy, thus maintaining the mitochondrial homeostasis.

Keywords:  Diabetic kidney disease; Mitophagy; Nrf2; PINK1; Podocyte; Sulforaphane

DOI:  https://doi.org/10.1016/j.ejphar.2023.176042
Sci Total Environ. 2023 Sep 06. pii: S0048-9697(23)05515-8. [Epub ahead of print] 166890

New insights into brain injury in chickens induced by bisphenol A and selenium deficiency-Mitochondrial reactive oxygen species and mitophagy-apoptosis crosstalk homeostasis.

Huanyi Liu, Hongjin Lin, Tong Xu, Xu Shi, Yujie Yao, Pervez Ahmed Khoso, Zhihui Jiang, Shiwen Xu.

  Bisphenol A (BPA), a component of plastic products, can penetrate the blood-brain barrier and pose a threat to the nervous system. Selenium (Se) deficiency can also cause nervous system damage. Resulting from the rapid industrial development, BPA pollution and Se deficiency often coexist. However, it is unclear whether brain damage in chickens caused by BPA exposure and Se deficiency is related to the crosstalk disorder between mitophagy and apoptosis. In this study, 60 chickens (1 day old) were fed with a diet that contained 20 mg/kg BPA but was insufficient in Se (only 0.039 mg/kg) for 42 days to establish a chicken brain injury model. In vitro, the primary chicken embryo brain neurons were treated for 24 h with Se-deficient medium containing 75 μM BPA. The results showed that BPA exposure and Se deficiency inhibited the expression of the mitochondrial respiratory chain complex in brain neurons, and a large number of mitochondrial reactive oxygen species were released. Furthermore, the expression levels of mitochondrial fusion proteins (OPA1, Mfn1, and Mfn2) decreased, while the expression levels of mitochondrial fission proteins (Drp1, Mff, and Fis1) increased, thus exacerbating mitochondrial division. In addition, the results of immunofluorescence and flow cytometry analysis, as well as the elevated expressions of mitophagy related genes (PINK1, Parkin, ATG5, and LC3II/I) and pro-apoptotic markers (Bax, Cytc, Caspase3, and Caspase9) indicated that BPA exposure and Se deficiency disrupted the crosstalk homeostasis between mitophagy and apoptosis. However, this crosstalk homeostasis was restored after Mito-Tempo and Rapamycin treatment. In contrast, 3-methyladenine treatment exacerbated this crosstalk disorder. In conclusion, BPA exposure and Se deficiency can induce mitochondrial reactive oxygen species bursts and disorders of mitochondrial dynamics by destroying the mitochondrial respiratory chain complex. The result is indicative of an imbalance in mitochondrial autophagy and apoptosis crosstalk homeostasis, which damages the chicken brain.

Keywords:  Bisphenol A; Chicken brain; Mitochondrial reactive oxygen species; Mitophagy-apoptosis crosstalk homeostasis; Selenium deficiency

DOI:  https://doi.org/10.1016/j.scitotenv.2023.166890
Phytomedicine. 2023 Aug 19. pii: S0944-7113(23)00403-8. [Epub ahead of print]120 155042

Activation of ULK1 to trigger FUNDC1-mediated mitophagy in heart failure: Effect of Ginsenoside Rg3 intervention.

Xiaoping Wang, Guanjing Ling, Yan Wei, Weili Li, Yawen Zhang, Nannan Tan, Wei Li, Haijing Li, Qi Qiu, Wei Wang, Yong Wang.

   BACKGROUND: Although the development of therapies for heart failure (HF) continues apace, clinical outcomes are often far from ideal. Unc51-like-kinase 1 (ULK1)-mediated mitophagy prevents pathological cardiac remodeling and heart failure (HF). Molecularly ULK1-targeted agent to enhance mitophagy is scanty.
HYPOTHESIS/PURPOSE: This study aimed to investigate whether Ginsenoside Rg3 (Rg3) can activate ULK1 to trigger FUNDC1-mediated mitophagy for protecting heart failure.
METHODS: Molecular docking and surface plasmon resonance were used to detect the ULK1 binding behavior of Rg3. Established HF model in rats and transcriptome sequencing were used to evaluate the therapeutic effect and regulatory mechanism of Rg3. Loss-of-function approaches in vivo and in vitro were performed to determine the role of ULK1 in Rg3-elicited myocardial protection against HF. FUNDC1 recombinant plasmid of site mutation was applied to elucidate more in-depth mechanisms.
RESULTS: Structurally, a good binding mode was unveiled between ULK1 and Rg3. In vivo, Rg3 improved cardiac dysfunction, adverse remodeling, and mitochondrial damage in HF rats. Furthermore, Rg3 promoted Ulk1-triggered mitophagy both in vivo and in vitro, manifested by the impetus of downstream Fundc1-Lc3 interaction. Of note, the protective effects conferred by Rg3 against mitophagy defects, pathological remodeling, and cardiac dysfunction were compromised by Ulk1 gene silencing both in vivo and in vitro. Mechanistically, Rg3 activated mitophagy by inducing ULK1-mediated phosphorylation of FUNDC1 at the Ser17 site, not the Ser13 site.
CONCLUSION: Together these observations demonstrated that Rg3 acts as a ULK1 activator for the precise treatment of HF, which binds to ULK1 to activate FUNDC1-mediated mitophagy.

Keywords:  Ginsenoside Rg3; Heart failure; Mitophagy; ULK1

DOI:  https://doi.org/10.1016/j.phymed.2023.155042
Fish Shellfish Immunol. 2023 Sep 01. pii: S1050-4648(23)00532-6. [Epub ahead of print]141 109046

New insights into Microalgal astaxanthin's effect on Lambda-cyhalothrin-induced lymphocytes immunotoxicity in Cyprinus carpio: Involving miRNA-194-5p-FoxO1-mediated-mitophagy and pyroptosis.

Jingzeng Cai, Haoyue Guan, Di Li, Bendong Shi, Yangyang Jiang, Senqiu Qiao, Qiaohan Liu, Cheng Fang, Ziwei Zhang.

  Lambda-cyhalothrin (LC), a pyrethroid insecticide widely used in agriculture, causes immunotoxicity to aquatic organisms in the aquatic environment. Microalgal astaxanthin (MA) is a natural carotenoid that enhances viability of a variety of fish. To investigate the immunotoxicity of LC and the improvement effect of MA in lymphocytes (Cyprinus carpio), lymphocytes were treated with LC (80 M) and/or MA (50 M) for 24 h. Firstly, CCK8 combined with PI staining results showed that MA significantly attenuated the LC-induced lymphocyte death rate. Secondly, LC exposure resulted in excessively damaged mitochondrial and mtROS, diminished mitochondrial membrane potential and ATP content, which could be improved by MA. Thirdly, MA upregulated the levels of mitophagy-related regulatory factors (Beclin1, LC3, ATG5, Tom20 and Lamp2) induced by LC. Importantly, MA decreased the levels of pyroptosis-related genes treated with LC, including NLRP3, Cas-4, GSDMD and active Cas-1. Further study indicated that LC treatment caused excessive miRNA-194-5p and reduced levels of FoxO1, PINK1 and Parkin, which was inhibited by MA treatment. Overall, we concluded that MA could enhance damaged mitochondrial elimination by promoting the miRNA-194-5p-FoxO1-PINK1/Parkin-mitophagy in lymphocytes, which reduced mtROS accumulation and alleviated pyroptosis. It offers insights into the importance of MA application in aquaculture as well as the defense of farmed fish against agrobiological hazards in fish under LC.

Keywords:  Lambda-cyhalothrin; Lymphocytes in fish; Microalgal astaxanthin; Mitophagy; Pyroptosis

DOI:  https://doi.org/10.1016/j.fsi.2023.109046
Life Sci. 2023 Sep 02. pii: S0024-3205(23)00698-7. [Epub ahead of print] 122063

MitoQ combats tumor cell progression in Ehrlich ascites carcinoma mice: A crosstalk between mitochondrial oxidative status, mitophagy, and NF-κB signaling.

Mamdouh A Oraby, Ola Elazazy, Heba M Karam, Doaa S Fadaly, Ayman A Ibrahim.

  Despite the clinical advances in cancer treatment, the high mortality rate is still a great challenge, requiring much effort to find new and efficient cancer therapies.
AIMS: The present evidence investigated the potential antiproliferative impact of the mitochondrial-targeted antioxidant, Mitoquinol (MitoQ), on a mouse model of Ehrlich ascites carcinoma (EAC).
MAIN METHODS: Mice-bearing tumors were administered two doses of MitoQ (0.3 mg & 0.5 mg/kg; i.p daily) or doxorubicin (2 mg/kg; i.p daily) for 20 days.
KEY FINDINGS: EAC mice revealed exacerbated mitochondrial reactive oxygen species (mtROS) and impaired mitochondrial membrane potential (△Ψm). Dysfunctional mitophagy was observed in EAC mice, along with boosting aerobic glycolysis. In addition, tumor cells exhibited higher proliferation rates, thereby stimulating cell cycle, invasion, and angiogenesis biomarkers together with suppressing proapoptotic proteins, events that might be correlated with activation of NF-κB signaling. The administration of MitoQ combated tumor cell survival and dissemination in EAC mice as evidenced by reducing tumor volumes and weights and increasing the number of necrotic areas in histopathological assessment. MitoQ also repressed tumor cell cycle, invasion, and angiogenesis via preventing cyclin D1 mRNA, MMP-1, and CD34 levels as well as VEGF protein expression. These observations were associated with the abrogation of mtROS overproduction and enhancement of the mitophagy proteins, PINK1/Parkin levels, followed by inhibition of NADH dehydrogenase. Notably, NF-κB signaling was modulated.
SIGNIFICANCE: This study suggests that MitoQ combated tumor cell survival and progression in EAC mice by maintaining mtROS and restoring mitophagy, thereby attenuation of NF-κB activation.

Keywords:  Doxorubicin; Ehrlich ascites carcinoma; MitoQ; Mitophagy; Mitoquinol; Solid tumor

DOI:  https://doi.org/10.1016/j.lfs.2023.122063
Int J Mol Med. 2023 Oct;pii: 99. [Epub ahead of print]52(4):

UCHL1 alleviates apoptosis in chondrocytes via upregulation of HIF‑1α‑mediated mitophagy.

Qiqian Yan, Shanwei Shi, Yang Ge, Shuangquan Wan, Mingfei Li, Maoquan Li.

  Stem cell‑based tissue engineering has shown significant potential for rapid restoration of injured cartilage tissues. Stem cells frequently undergo apoptosis because of the prevalence of oxidative stress and inflammation in the microenvironment at the sites of injury. Our previous study demonstrated that stabilization of hypoxia‑inducible factor 1α (HIF‑1α) is key to resisting apoptosis in chondrocytes. Recently, it was reported that Ubiquitin C‑terminal hydrolase L1 (UCHL1) can stabilize HIF‑1α by abrogating the ubiquitination process. However, the effect of UCHL1 on apoptosis in chondrocytes remains unclear. Herein, adipose‑derived stem cells were differentiated into chondrocytes. Next, the CRISPR activation (CRISPRa) system, LDN‑57444 (LDM; a specific inhibitor for UCHL1), KC7F2 (a specific inhibitor for HIF‑1α), and 3‑methyladenine (a specific inhibitor for mitophagy) were used to activate or block UCHL1, HIF‑1α, and mitophagy. Mitophagy, apoptosis, and mitochondrial function in chondrocytes were detected using immunofluorescence, TUNEL staining, and flow cytometry. Moreover, the oxygen consumption rate of chondrocytes was measured using the Seahorse XF 96 Extracellular Flux Analyzer. UCHL1 expression was increased in hypoxia, which in turn regulated mitophagy and apoptosis in the chondrocytes. Further studies revealed that UCHL1 mediated hypoxia‑regulated mitophagy in the chondrocytes. The CRISPRa module was utilized to activate UCHL1 effectively for 7 days; endogenous activation of UCHL1 accelerated mitophagy, inhibited apoptosis, and maintained mitochondrial function in the chondrocytes, which was mediated by HIF‑1α. Taken together, UCHL1 could block apoptosis in chondrocytes via upregulation of HIF‑1α-mediated mitophagy and maintain mitochondrial function. These results indicate the potential of UCHL1 activation using the CRISPRa system for the regeneration of cartilage tissue.

Keywords:  ADSCs; CRISPR; HIF‑1α; UCHL1; apoptosis; mitophagy

DOI:  https://doi.org/10.3892/ijmm.2023.5302
Macromol Biosci. 2023 Sep 07. e2300116

Fighting Against Drug-resistant Tumor by The Induction of Excessive Mitophagy with Transferrin Nanomedicine.

Yuanxiang Yu, Sijin Chen, Yupeng Wang, Dongfang Zhou, Dehua Wu.

  The effectiveness of chemotherapy is primarily hindered by drug resistance, and autophagy plays a crucial role in overcoming this resistance. In this project, we have developed a human transferrin nanomedicine known as HTf@DOX/Qu NPs, which contains quercetin (a drug to induces excessive autophagy) and doxorubicin. The purpose of this nanomedicine is to enhance mitophagy and combating drug-resistant cancer. Through in vitro studies, we have demonstrated that HTf@DOX/Qu NPs can effectively downregulate cyclooxygenase-2 (COX-2), leading to an excessive promotion of mitophagy and subsequent mitochondrial dysfunction via the PINK1/Parkin axis. Additionally, HTf@DOX/Qu NPs can upregulate proapoptotic proteins to induce cellular apoptosis, thereby effectively reversing drug resistance. Furthermore, in vivo results have shown that HTf@DOX/Qu NPs exhibit prolonged circulation in the bloodstream, enhanced drug accumulation in tumors, and superior therapeutic efficacy compared to individual chemotherapy in a drug-resistant tumor model. This study presents a promising strategy for combating multidrug-resistant cancers by exacerbating mitophagy through the use of transferrin nanoparticles. This article is protected by copyright. All rights reserved.

Keywords:  cancer therapy; excessive mitophagy; multidrug resistance; quercetin; transferrin nanoparticles

DOI:  https://doi.org/10.1002/mabi.202300116
Exp Ther Med. 2023 Oct;26(4): 463

Effects of DJ‑1 on apoptosis and mitophagy of glomerular podocytes.

Jing Xiao, Junjie Tan, Li Yu, Guosheng Liu, Shengyou Yu.

  By studying the effects of DJ-1 overexpression and silencing on the morphological structure and mitophagy of glomerular podocytes, the present study aimed to identify the effects of DJ-1 on glomerular podocyte apoptosis and mitophagy. MPC5 mouse glomerular podocytes were cultured in vitro and divided into four groups: Control, DJ-1 overexpression, empty vector and DJ-1 silencing. DJ-1 gene overexpression and silencing models were prepared, the morphological structures of podocytes and mitochondria in each group were observed, and podocyte apoptosis and DJ-1/PTEN expression were subsequently detected in each group. The experimental results showed reduced volume, retracted foot processes, loosened intercellular connections, presence of dead cells, increased apoptotic rate, increased expression of PTEN, and swollen mitochondria due to the number of vacuoles and autophagosomes in podocytes in the DJ-1 silencing group. The surface areas of podocytes in the DJ-1 overexpression group were greater than those in the control group. Moreover, the structure of the foot processes was more obvious, the number of cells was greater, the intercellular connections were closer, the apoptotic rate was reduced, the expression of PTEN was decreased, the mitochondrial structure was more obvious and the mitochondrial cristae were more whole. Notably, there were no differences between the empty vector and control groups. In conclusion, these results indicated that DJ-1 may regulate podocyte apoptosis and mitophagy through the DJ-1/PTEN pathway, and could maintain the stability of the normal morphology, structure and function of glomerular podocytes.

Keywords:  DJ-1; PTEN; autophagy; mitochondria; podocytes; proteinuria

DOI:  https://doi.org/10.3892/etm.2023.12162
Cell Death Dis. 2023 Sep 07. 14(9): 598

Exploring a new mechanism between lactate and VSMC calcification: PARP1/POLG/UCP2 signaling pathway and imbalance of mitochondrial homeostasis.

Yi Zhu, Jia-Li Zhang, Xue-Jiao Yan, Yuan Ji, Fang-Fang Wang.

Lactate leads to the imbalance of mitochondria homeostasis, which then promotes vascular calcification. PARP1 can upregulate osteogenic genes and accelerate vascular calcification. However, the relationship among lactate, PARP1, and mitochondrial homeostasis is unclear. The present study aimed to explore the new molecular mechanism of lactate to promote VSMC calcification by evaluating PARP1 as a breakthrough molecule. A coculture model of VECs and VSMCs was established, and the model revealed that the glycolysis ability and lactate production of VECs were significantly enhanced after incubation in DOM. Osteogenic marker expression, calcium deposition, and apoptosis in VSMCs were decreased after lactate dehydrogenase A knockdown in VECs. Mechanistically, exogenous lactate increased the overall level of PARP and PARylation in VSMCs. PARP1 knockdown inhibited Drp1-mediated mitochondrial fission and partially restored PINK1/Parkin-mediated mitophagy, thereby reducing mitochondrial oxidative stress. Moreover, lactate induced the translocation of PARP1 from the nucleus to the mitochondria, which then combined with POLG and inhibited POLG-mediated mitochondrial DNA synthesis. This process led to the downregulation of mitochondria-encoded genes, disturbance of mitochondrial respiration, and inhibition of oxidative phosphorylation. The knockdown of PARP1 could partially reverse the damage of mitochondrial gene expression and function caused by lactate. Furthermore, UCP2 was upregulated by the PARP1/POLG signal, and UCP2 knockdown inhibited Drp1-mediated mitochondrial fission and partially recovered PINK1/Parkin-mediated mitophagy. Finally, UCP2 knockdown in VSMCs alleviated DOM-caused VSMC calcification in the coculture model. The study results thus suggest that upregulated PARP1 is involved in the mechanism through which lactate accelerates VSMC calcification partly via POLG/UCP2-caused unbalanced mitochondrial homeostasis.

DOI: https://doi.org/10.1038/s41419-023-06113-3
Cell Death Dis. 2023 09 02. 14(9): 585

BCL2L13 promotes mitophagy through DNM1L-mediated mitochondrial fission in glioblastoma.

Jiwei Wang, Anbin Chen, Zhiwei Xue, Junzhi Liu, Ying He, Guowei Liu, Zhimin Zhao, Wenjie Li, Qing Zhang, Anjing Chen, Jian Wang, Xingang Li, Xinyu Wang, Bin Huang.

There is an urgent need for novel diagnostic and therapeutic strategies for patients with Glioblastoma multiforme (GBM). Previous studies have shown that BCL2 like 13 (BCL2L13) is a member of the BCL2 family regulating cell growth and apoptosis in different types of tumors. However, the clinical significance, biological role, and potential mechanism in GBM remain unexplored. In this study, we showed that BCL2L13 expression is significantly upregulated in GBM cell lines and clinical GBM tissue samples. Mechanistically, BCL2L13 targeted DNM1L at the Ser616 site, leading to mitochondrial fission and high mitophagy flux. Functionally, these alterations significantly promoted the proliferation and invasion of GBM cells both in vitro and in vivo. Overall, our findings demonstrated that BCL2L13 plays a significant role in promoting mitophagy via DNM1L-mediated mitochondrial fission in GBM. Therefore, the regulation and biological function of BCL2L13 render it a candidate molecular target for treating GBM.

DOI: https://doi.org/10.1038/s41419-023-06112-4
Dev Cell. 2023 Aug 30. pii: S1534-5807(23)00410-0. [Epub ahead of print]

Mammalian autophagosomes form from finger-like phagophores.

Claudia Puri, Matthew J Gratian, David C Rubinsztein.

  The sequence of morphological intermediates that leads to mammalian autophagosome formation and closure is a crucial yet poorly understood issue. Previous studies have shown that yeast autophagosomes evolve from cup-shaped phagophores with only one closure point, and mammalian studies have inferred that mammalian phagophores also have single openings. Our superresolution microscopy studies in different human cell lines in conditions of basal and nutrient-deprivation-induced autophagy identified autophagosome precursors with multifocal origins that evolved into unexpected finger-like phagophores with multiple openings before becoming more spherical structures. Compatible phagophore structures were observed with whole-mount and conventional electron microscopy. This sequence of events was visualized using advanced SIM2 superresolution live microscopy. The finger-shaped phagophore apertures remained open when ESCRT function was compromised. The efficient closure of autophagic structures is important for their release from the recycling endosome. This has important implications for understanding how autophagosomes form and capture various cargoes.

Keywords:  CHMP2A; ESCRT complex; RAB11A; VPS4A; autophagosome; autophagy; mitophagy; phagophore; recycling endosome; superresolution microscopy

DOI:  https://doi.org/10.1016/j.devcel.2023.08.016