PINK1-Parkin Pathway Research Articles

Duck Tembusu virus induced mitophagy in vacuolate spermatogenic cells is mediated by PINK1-Parkin pathway.

As a significant emerging and re-emerging pathogen in China, the widely spread of Duck Tembusu virus (DTMUV) caused enormous economic losses to poultry industry. On account of DTMUV diseases' main symptoms on haemorrhagic oophoritis, intensive attentions were focused on female reproductive organ. Nevertheless, the DTMUV infection of sperm and testis manifested that testis was an important vector for vertical transmission of DTMUV. In the present study, histopathology, immunofluorescence and transmission electron microscopy (TEM) analysis of DTMUV-infected duck testis revealed that DTMUV infection induced seminiferous epithelium injury via spermatogenic cells vacuolization. After DTMUV infection, the expression of autophagy-related genes and proteins in testis were significantly up-regulated. Further TEM analysis discovered that different stages of autophagic and mitophagy structures were visible in cytoplasm of spermatogenic cells after DTMUV infection. And more notably, the testicular protein expression of PINK1 and Parkin were significantly increased after DTMUV infection. In summary, our study discovered that, after DTMUV infection, PINK1-Parkin pathway mediated mitophagy were activated and then induced spermatogenic cells vacuolization.

Di Huang Yi Zhi Fang improves cognitive function in APP/PS1 mice by inducing neuronal mitochondrial autophagy through the PINK1-parkin pathway.

Alzheimer's disease (AD) is an irreversible age-related neurodegenerative condition characterized by the deposition of amyloid-β (Aβ) peptides and neurofibrillary tangles. Di Huang Yi Zhi (DHYZ) formula, a traditional Chinese herbal compound comprising several prescriptions, demonstrates properties that improve cognitive abilities in clinical. Nonetheless, its molecular mechanisms on treating AD through improving neuron cells mitochondria function have not been deeply investigated. This study administered DHYZ to APP/PS1 mice to explore its potential therapeutic mechanisms in AD treatment. APP/PS1 transgenic mice were given DHYZ (L, M, H), donepezil, or distilled water for a consecutive 12-week period. The Morris water maze test was used to assess memory capacity, transmission electron microscopy was used to observe mitochondrial and synaptic structures, immunohistochemistry and western blot detected proteins involved in the mitochondrial autophagy pathway, ELISA measured serum Aβ content, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assessed neuronal cell apoptosis. DHYZ demonstrates a notable therapeutic impact on mice with AD, effectively improving cognitive and memory impairments. DHYZ decreases Aβ accumulation in the hippocampus by reducing BACE1 activity and enhancing Aβ clearance through the blood-brain barrier. Additionally, DHYZ significantly suppresses neuronal apoptosis, enhances synaptic structure, and increases synapse numbers, processes strongly linked to the activation of mitochondrial PINK1-Parkin autophagy. DHYZ enhances cognitive function in APP/PS1 mice by stimulating neuronal mitochondrial autophagy through the PINK1-Parkin pathway.

SQYC formula improves the efficacy of PD-1 monoclonal antibodies in MSS colorectal cancer by regulating dendritic cell mitophagy via the PINK1-Parkin pathway.

Microsatellite stable (MSS) colorectal carcinomas (CRCs) exhibit poor responsiveness to immunotherapy such as immune checkpoint inhibitors (ICIs). In the realm of clinical cancer treatment, traditional Chinese medicines (TCMs) are extensively utilized for their immunomodulatory properties. Shen Qi Yi Chang (SQYC), a clinical prescription for CRC treatment, improve the life quality of CRC patients and enhance their immune function. This study was to reveal the effect and mechanism of SQYC in improving the effect of PD-1 inhibitors in the treatment of MSS-type CRC. CT26-luc in situ CRC tumor model and human CRC organoid model was established to evaluate the anti-tumor efficacy of SQYC combined with PD-1 inhibitor. Flow cytometry analysis was utilized to investigate the effect of SQYC on the infiltration and immune function of TILs and DCs in the immune microenvironment. Following this, RNA sequencing analysis, seahorse, TEM and immunofluorescence were performed to regulation of SQYC on mitophagy in DCs cells. UPLC-Q-TOF/MS and molecular docking were used to reveal the key blood-entering components of SQYC-regulated PINK1-parkin pathway. The SQYC-containing serum improved the efficacy of sintilimab in MSS CRC organoid model. After combined administration of 11.4 g/kg/day SQYC extract and 5 mg/kg α-PD-1, it was observed that SQYC enhanced the efficacy of PD-1 inhibitor against MSS CRC. Flow cytometry and immunofluorescence analysis revealed an augmented infiltration of tumor-infiltrating lymphocytes (TILs) and an improved antigen presentation function of dendritic cells (DCs). Notably, RNA sequencing analysis demonstrated an evident correlation with mitochondrial function related pathways following SQYC treatment. Mechanistically, SQYC promoted mitophagy in DCs via the PINK1-Parkin pathway, thereby improving mitochondrial quality, energy metabolism, and mitochondrial dynamics. Evaluation of the blood components of SQYC coupled with molecular docking, demonstrated good binding affinity with PINK1/PARKIN/LC3. Our findings highlight SQYC as a promising candidate for improving immunotherapy in MSS CRC, suggesting that targeting PINK1-Parkin in DCs could represent a novel strategy for improving the efficacy of ICIs. Furthermore, it provides new theoretical and scientific underpinnings to enhance the clinical efficacy of immunosuppressants.

Fasting enhances the efficacy of Sorafenib in breast cancer via mitophagy mediated ROS-driven p53 pathway.

The multi-kinase inhibitor sorafenib has shown potential to inhibit tumor cell growth and intra-tumoral angiogenesis by targeting several kinases, including VEGFR2 and RAF. Abnormal activation of the Ras/Raf/MAPK/ERK kinase cascade and the VEGF pathway is a common feature in breast cancer. However, the efficacy of sorafenib in breast cancer treatment remains limited. Recently, fasting has emerged as a promising non-pharmacological approach to modulate cancer metabolism and enhance the effectiveness of cancer therapies. In this study, we found that fasting significantly enhances the anti-cancer effects of sorafenib monotherapy and its combination with immunotherapy in breast cancer models without causing obvious side effects. This combined treatment effectively inhibits tumor cell proliferation and intra-tumoral angiogenesis. The fasting-induced reduction in peripheral blood glucose levels strongly correlated with enhanced sensitivity to sorafenib. Mechanistically, the combined treatment induced mitophagy, characterized by mitochondrial dysfunction and activation of the PINK1-Parkin pathway. Consequently, increased mitochondrial ROS levels promoted p53 expression, amplifying cell cycle arrest and apoptosis in breast cancer cells. Furthermore, fasting reduced lactate levels within the tumor, and the consequent glucose limitation synergized with sorafenib to activate AMPK, which in turn elevated PD-L1 expression in tumor cells, potentially enhancing their sensitivity to immunotherapy. In summary, our findings demonstrate that fasting and sorafenib, as a rational combination therapy, induce mitophagy, thereby enhancing sorafenib's efficacy in treating breast cancer through the ROS-driven p53 pathway. This study underscores the potential of fasting in breast cancer therapy and provides a foundation for optimizing the clinical application of sorafenib.

Mitophagy and its regulatory mechanisms in the biological effects of nanomaterials.

Mitophagy is a selective cellular process critical for the removal of damaged mitochondria. It is essential in regulating mitochondrial number, ensuring mitochondrial functionality, and maintaining cellular equilibrium, ultimately influencing cell destiny. Numerous pathologies, such as neurodegenerative diseases, cardiovascular disorders, cancers, and various other conditions, are associated with mitochondrial dysfunctions. Thus, a detailed exploration of the regulatory mechanisms of mitophagy is pivotal for enhancing our understanding and for the discovery of novel preventive and therapeutic options for these diseases. Nanomaterials have become integral in biomedicine and various other sectors, offering advanced solutions for medical uses including biological imaging, drug delivery, and disease diagnostics and therapy. Mitophagy is vital in managing the cellular effects elicited by nanomaterials. This review provides a comprehensive analysis of the molecular mechanisms underpinning mitophagy, underscoring its significant influence on the biological responses of cells to nanomaterials. Nanoparticles can initiate mitophagy via various pathways, among which the PINK1-Parkin pathway is critical for cellular defense against nanomaterial-induced damage by promoting mitophagy. The role of mitophagy in biological effects was induced by nanomaterials, which are associated with alterations in Ca2+ levels, the production of reactive oxygen species, endoplasmic reticulum stress, and lysosomal damage.

ABALON regulates mitophagy and 5-FU sensitivity in colorectal cancer via PINK1-Parkin pathway.

Growing evidence demonstrated that long non-coding RNAs (lncRNAs) are closely related with chemoresistance in colorectal cancer (CRC). Mitophagy serves as an essential factor to maintain the quality of tumor cells. However, it is unclear whether lncRNAs are involved in mitophagy regulation in CRC. The aim of this study is to evaluate whether lncRNAs are involved in regulating mitophagy and chemoresistance in CRC. In this study, gain/loss of function was used to analyze the biological function influenced by apoptotic BCL2L1-antisense long non-coding RNA (ABALON). Western blot and JC-1 probe were carried out for detecting mitophagy. Chemosensitivity of CRC cells to 5-fluorouracil (5-FU) was determined using cell counting kit-8 (CCK-8), flow cytometry, colony formation and trans well assays. We found that ABALON expression was increased in CRC, especially in consensus molecular subtype 1 (CMS1) and highly expressed ABALON was related with tumor differentiation, tumor node metastasis (TNM) staging, and lymph node metastasis (P<0.05). ABALON knockdown led to impaired proliferation and enhanced apoptosis in CRC. Mitophagy variations primed by ABALON enhanced mitochondrial homeostasis. The half maximal inhibitory concentration (IC50) of 5-FU in ABALON interference groups declined, while ABALON overexpression elevated IC50. Furthermore, defective mitophagy not only rescued the proliferation, metastasis, and apoptosis induced by ABALON overexpression, but also, enhanced the anti-tumor effect of 5-FU in vivo. Collectively, our study proposed that ABALON potentiates CRC progression via PINK1/Parkin mediated mitophagy, and ABALON is a promising therapeutic target in reversing 5-FU resistance.

Sestrin2 balances mitophagy and apoptosis through the PINK1-Parkin pathway to attenuate severe acute pancreatitis

Mitophagy serves as a mitochondrial quality control mechanism to maintain the homeostasis of mitochondria and the intracellular environment. Studies have shown that there is a close relationship between mitophagy and apoptosis. Sestrin2 (Sesn2) is a highly conserved class of stress-inducible proteins that play important roles in reducing oxidative stress damage, inflammation, and apoptosis. However, the potential mechanism of how Sesn2 regulates mitophagy and apoptosis in severe acute pancreatitis (SAP) remains unclear. In the study, RAW264.7 (macrophage cell Line) cellular inflammation model established by lipopolysaccharide (LPS) treatment as well as LPS and CAE-induced SAP mouse model (wild-type and Sen2 Knockout mouse) were used. Our study showed that LPS stimulation significantly increased the level of Sesn2 in RAW264.7 cells, Sesn2 increased mitochondrial membrane potential, decreased inflammation levels, mitochondrial superoxide levels and apoptosis, and also promoted monocyte macrophages toward the M2 anti-inflammatory phenotype, suggesting a protective effect of Sesn2 on mitochondria. Further, Sesn2 increased mitophagy and decreased apoptosis via modulating the PINK1-Parkin signaling. Meanwhile, knockout of Sesn2 exacerbated pancreatic, mitochondrial damage and inflammation in a mouse model of SAP. In addition, the protective effect of Sesn2 against SAP was shown to be associated with mitophagy conducted by the PINK1-Parkin pathway via inhibiting apoptosis. These findings reveal that Sesn2 in balancing mitochondrial autophagy and apoptosis by modulating the PINK1-Parkin signaling may present a new therapeutic strategy for the treatment of SAP.

Retinal G-protein-coupled receptor deletion exacerbates AMD-like changes via the PINK1-parkin pathway under oxidative stress.

The intake of high dietary fat has been correlated with the progression of age-related macular degeneration (AMD), affecting the function of the retinal pigment epithelium through oxidative stress. A high-fat diet (HFD) can lead to lipid metabolism disorders, excessive production of circulating free fatty acids, and systemic inflammation by aggravating the degree of oxidative stress. Deletion of the retinal G-protein-coupled receptor (RGR-d) has been identified in drusen. In this study, we investigated how the RGR-d exacerbates AMD-like changes under oxidative stress, both invivo and invitro. Fundus atrophy became evident, at 12 months old, particularly in the RGR-d + HFD group, and fluorescence angiography revealed narrower retinal vessels and a reduced perfusion area in the peripheral retina. Although rod electroretinography revealed decreasing trends in the a- and b-wave amplitudes in the RGR-d + HFD group at 12 months, the changes were not statistically significant. Mice in the RGR-d + HFD group showed a significantly thinner and more fragile retinal morphology than those in the WT + HFD group, with disordered and discontinuous pigment distribution in the RGR-d + HFD mice. Transmission electron microscopy revealed a thickened Bruch's membrane along the choriocapillaris endothelial cell wall in the RGR-d + HFD mice, and the outer nuclear layer structure appeared disorganized, with reduced nuclear density. Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated significantly lower levels of 25(OH)-vitamin D3 metabolites in the RGR-d + HFD group. Under oxidative stress, RGR-d localized to the mitochondria and reduced the levels of the PINK1-parkin pathway. RGR-d mice fed an HFD were used as a new animal model of dry AMD. Under high-fat-induced oxidative stress, RGR-d accumulated in the mitochondria, disrupting normal mitophagy and causing cellular damage, thus exacerbating AMD-like changes both invivo and invitro.

Nitidine Chloride Alleviates Hypoxic Stress via PINK1-Parkin-Mediated Mitophagy in the Mammary Epithelial Cells of Milk Buffalo.

Hypoxia in the mammary gland epithelial cells of milk buffalo (BMECs) can affect milk yield and composition, and it can even cause metabolic diseases. Nitidine chloride (NC) is a natural alkaloid with antioxidant properties that can scavenge excessive reactive oxygen species (ROS). However, the effect of NC on the hypoxic injury of BMECs and its molecular mechanisms are still unknown. Here, an immunofluorescence assay, transmission electron microscopy (TEM), and flow cytometry, combined with untargeted metabolomics, were used to investigate the protective effect of NC on hypoxic stress injury in BMECs. It was found that NC can significantly reduce cell activity (p < 0.05) and inhibit cellular oxidative stress (p < 0.05) and cell apoptosis (p < 0.05). A significant decrease in mitophagy mediated by the PINK1-Parkin pathway was observed after NC pretreatment (p < 0.05). In addition, a metabolic pathway enrichment analysis demonstrated that the mechanisms of NC against hypoxic stress may be related to the downregulation of pathways involving aminoacyl tRNA biosynthesis; arginine and proline metabolism; glycine, serine, and threonine metabolism; phenylalanine, tyrosine, and tryptophan biosynthesis; and phenylalanine metabolism. Thus, NC has a protective effect on hypoxic mitochondria, and it can regulate amino acid metabolism in response to hypoxic stress. The present study provides a reference for the application of nitidine chloride to regulate the mammary lactation function of milk buffalo.

The role of PINK1-Parkin in mitochondrial quality control.

Mitophagy mediated by the recessive Parkinson's disease genes PINK1 and Parkin responds to mitochondrial damage to preserve mitochondrial function. In the pathway, PINK1 is the damage sensor, probing the integrity of the mitochondrial import pathway, and activating Parkin when import is blocked. Parkin is the effector, selectively marking damaged mitochondria with ubiquitin for mitophagy and other quality-control processes. This selective mitochondrial quality-control pathway may be especially critical for dopamine neurons affected in Parkinson's disease, in which the mitochondrial network is widely distributed throughout a highly branched axonal arbor. Here we review the current understanding of the role of PINK1-Parkin in the quality control of mitophagy, including sensing of mitochondrial distress by PINK1, activation of Parkin by PINK1 to induce mitophagy, and the physiological relevance of the PINK1-Parkin pathway.

Effect of Spermidine on Endothelial Function in Systemic Lupus Erythematosus Mice.

Endothelial dysfunction is common in Systemic Lupus Erythematosus (SLE), even in the absence of cardiovascular disease. Evidence suggests that impaired mitophagy contributes to SLE. Mitochondrial dysfunction is also associated with impaired endothelial function. Spermidine, a natural polyamine, stimulates mitophagy by the PINK1-parkin pathway and counters age-associated endothelial dysfunction. However, the effect of spermidine on mitophagy and vascular function in SLE has not been explored. To address this gap, 9-week-old female lupus-prone (MRL/lpr) and healthy control (MRL/MpJ) mice were randomly assigned to spermidine treatment (lpr_Spermidine and MpJ_Spermidine) for 8 weeks or as control (lpr_Control and MpJ_Control). lpr_Control mice exhibited impaired endothelial function (e.g., decreased relaxation to acetylcholine), increased markers of inflammation, and lower protein content of parkin, a mitophagy marker, in the thoracic aorta. Spermidine treatment prevented endothelial dysfunction in MRL-lpr mice. Furthermore, aortas from lpr_Spermidine mice had lower levels of inflammatory markers and higher levels of parkin. Lupus phenotypes were not affected by spermidine. Collectively, these results demonstrate the beneficial effects of spermidine treatment on endothelial function, inflammation, and mitophagy in SLE mice. These results support future studies of the beneficial effects of spermidine on endothelial dysfunction and cardiovascular disease risk in SLE.

Deficiency in the mitophagy mediator Parkin accelerates murine skin allograft rejection

Alterations in mitochondrial function and associated quality control programs, including mitochondrial-specific autophagy, termed mitophagy, are gaining increasing recognition in the context of disease. However, the role of mitophagy in organ transplant rejection remains poorly understood. Using mice deficient in Parkin, a ubiquitin ligase that tags damaged or dysfunctional mitochondria for autophagic clearance, we assessed the impact of Parkin-dependent mitophagy on skin-graft rejection. We observed accelerated graft loss in Parkin-deficient mice across multiple skin graft models. Immune cell distributions posttransplant were largely unperturbed compared to wild-type; however, the CD8+ T cells of Parkin-deficient mice expressed more T-bet, IFNγ, and Ki67, indicating greater priming toward effector function. This was accompanied by increased circulating levels of IL-12p70 in Parkin-deficient mice. Using a mixed leukocyte reaction, we demonstrated that naïve Parkin-deficient CD4+ and CD8+ T cells exhibit enhanced activation marker expression and proliferative responses to alloantigen, which were attenuated with administration of a pharmacological mitophagy inducer (p62-mediated mitophagy inducer), known to increase mitophagy in the absence of a functional PINK1-Parkin pathway. These findings indicate a role for Parkin-dependent mitophagy in curtailing skin-graft rejection.

Macrophage migration inhibitory factor (MIF) suppresses mitophagy through disturbing the protein interaction of PINK1-Parkin in sepsis-associated acute kidney injury

Damage to renal tubular epithelial cells (RTECs) signaled the onset and progression of sepsis-associated acute kidney injury (SA-AKI). Recent research on mitochondria has revealed that mitophagy plays a crucial physiological role in alleviating injury to RTECs and it is suppressed progressively by the inflammation response in SA-AKI. However, the mechanism by which inflammation influences mitophagy remains poorly understood. We examined how macrophage migration inhibitory factor (MIF), a pro-inflammatory protein, influences the PINK1-Parkin pathway of mitophagy by studying protein–protein interactions when MIF was inhibited or overexpressed. Surprisingly, elevated levels of MIF were found to directly bind to PINK1, disrupting its interaction with Parkin. This interference hindered the recruitment of Parkin to mitochondria and impeded the initiation of mitophagy. Furthermore, this outcome led to significant apoptosis of RTECs, which could, however, be reversed by an MIF inhibitor ISO-1 and/or a new mitophagy activator T0467. These findings highlight the detrimental impact of MIF on renal damage through its disruption of the interaction between PINK1 and Parkin, and the therapeutic potential of ISO-1 and T0467 in mitigating SA-AKI. This study offers a fresh perspective on treating SA-AKI by targeting MIF and mitophagy.

Canagliflozin Mitigates Diabetic Cardiomyopathy through Enhanced PINK1-Parkin Mitophagy.

Diabetic cardiomyopathy (DCM) is a major determinant of mortality in diabetic populations, and the potential strategies are insufficient. Canagliflozin has emerged as a potential cardioprotective agent in diabetes, yet its underlying molecular mechanisms remain unclear. We employed a high-glucose challenge (60 mM for 48 h) in vitro to rat cardiomyocytes (H9C2), with or without canagliflozin treatment (20 µM). In vivo, male C57BL/6J mice were subjected to streptozotocin and a high-fat diet to induce diabetes, followed by canagliflozin administration (10, 30 mg·kg-1·d-1) for 12 weeks. Proteomics and echocardiography were used to assess the heart. Histopathological alterations were assessed by the use of Oil Red O and Masson's trichrome staining. Additionally, mitochondrial morphology and mitophagy were analyzed through biochemical and imaging techniques. A proteomic analysis highlighted alterations in mitochondrial and autophagy-related proteins after the treatment with canagliflozin. Diabetic conditions impaired mitochondrial respiration and ATP production, alongside decreasing the related expression of the PINK1-Parkin pathway. High-glucose conditions also reduced PGC-1α-TFAM signaling, which is responsible for mitochondrial biogenesis. Canagliflozin significantly alleviated cardiac dysfunction and improved mitochondrial function both in vitro and in vivo. Specifically, canagliflozin suppressed mitochondrial oxidative stress, enhancing ATP levels and sustaining mitochondrial respiratory capacity. It activated PINK1-Parkin-dependent mitophagy and improved mitochondrial function via increased phosphorylation of adenosine monophosphate-activated protein kinase (AMPK). Notably, PINK1 knockdown negated the beneficial effects of canagliflozin on mitochondrial integrity, underscoring the critical role of PINK1 in mediating these protective effects. Canagliflozin fosters PINK1-Parkin mitophagy and mitochondrial function, highlighting its potential as an effective treatment for DCM.

Acupotomy alleviates knee osteoarthritis in rabbit by regulating chondrocyte mitophagy Pink1-Parkin pathway.

To investigate the effect of acupotomy, on mitophagy and the Pink1-Parkin pathway in chondrocytes from rabbits with knee osteoarthritis (KOA). A KOA model was established via the modified Videman method. Rabbits were randomly divided into a control group (CON), KOA group and KOA + acupotomy group (Acu). Rabbits in the acupotomy group were subjected to acupotomy for 4 weeks after model establishment. The behavior of the rabbits before and after intervention was recorded. Cartilage degeneration was evaluated by optical microscopy and fluorescence microscopy. The level of mitophagy was evaluated by transmission electron microscopy, immunofluorescence and enzyme-linked immunosorbent assay (ELISA). The expression of phosphatase and tensin homolog (PTEN)-induced kinase 1 (Pink1)-Parkin mitophagy pathway components was evaluated by immunofluorescence, Western blotting and real-time polymerase chain reaction. In rabbits with KOA, joint pain, mobility disorders and cartilage degeneration were observed, the Mankin score was increased, collagen type Ⅱ (Col-Ⅱ) expression was significantly decreased, mitophagy was inhibited, mitochondrial function was impaired, and factors associated with the Pink1-Parkin pathway were inhibited. Acupotomy regulated the expression of Pink1-Parkin pathway-related proteins, the mitophagy-related protein microtubule-associated protein-1 light chain-3, the translocase of the outer membrane, and the inner mitochondrial membrane 23; increased the colocalization of mitochondria and autophagosomes; promoted the removal of damaged mitochondria; restored mitochondrial adenosine-triphosphate (ATP) production; and alleviated cartilage degeneration in rabbits with KOA. Acupotomy played a role in alleviating KOA in rabbits by activating mitophagy in chondrocytes via the regulation of proteins that are related to the Pink1-Parkin pathway.

Mitochondrial transfer mediates endothelial cell engraftment through mitophagy.

Ischaemic diseases such as critical limb ischaemia and myocardial infarction affect millions of people worldwide1. Transplanting endothelial cells (ECs) is a promising therapy in vascular medicine, but engrafting ECs typically necessitates co-transplanting perivascular supporting cells such as mesenchymal stromal cells (MSCs), which makes clinical implementation complicated2,3. The mechanisms that enable MSCs to facilitate EC engraftment remain elusive. Here we show that, under cellular stress, MSCs transfer mitochondria to ECs through tunnelling nanotubes, and that blocking this transfer impairs EC engraftment. We devised a strategy to artificially transplant mitochondria, transiently enhancing EC bioenergetics and enabling them to form functional vessels in ischaemic tissues without the support of MSCs. Notably, exogenous mitochondria did not integrate into the endogenous EC mitochondrial pool, but triggered mitophagy after internalization. Transplanted mitochondria co-localized with autophagosomes, and ablation of the PINK1-Parkin pathway negated the enhanced engraftment ability of ECs. Our findings reveal a mechanism that underlies the effects of mitochondrial transfer between mesenchymal and endothelial cells, and offer potential for a new approach for vascular cell therapy.

The Mst1/2-BNIP3 axis is required for mitophagy induction and neuronal viability under mitochondrial stress

Mitophagy induction upon mitochondrial stress is critical for maintaining mitochondrial homeostasis and cellular function. Here, we found that Mst1/2 (Stk3/4), key regulators of the Hippo pathway, are required for the induction of mitophagy under various mitochondrial stress conditions. Knockdown of Mst1/2 or pharmacological inhibition by XMU-MP-1 treatment led to impaired mitophagy induction upon CCCP and DFP treatment. Mechanistically, Mst1/2 induces mitophagy independently of the PINK1-Parkin pathway and the canonical Hippo pathway. Moreover, our results suggest the essential involvement of BNIP3 in Mst1/2-mediated mitophagy induction upon mitochondrial stress. Notably, Mst1/2 knockdown diminishes mitophagy induction, exacerbates mitochondrial dysfunction, and reduces cellular survival upon neurotoxic stress in both SH-SY5Y cells and Drosophila models. Conversely, Mst1 and Mst2 expression enhances mitophagy induction and cell survival. In addition, AAV-mediated Mst1 expression reduced the loss of TH-positive neurons, ameliorated behavioral deficits, and improved mitochondrial function in an MPTP-induced Parkinson’s disease mouse model. Our findings reveal the Mst1/2-BNIP3 regulatory axis as a novel mediator of mitophagy induction under conditions of mitochondrial stress and suggest that Mst1/2 play a pivotal role in maintaining mitochondrial function and neuronal viability in response to neurotoxic treatment.

Cloflucarban Illuminates Specificity and Context-Dependent Activation of the PINK1-Parkin Pathway by Mitochondrial Complex Inhibition.

The PTEN-induced kinase 1 (PINK1)-Parkin pathway plays a vital role in maintaining a healthy pool of mitochondria in higher eukaryotic cells. While the downstream components of this pathway are well understood, the upstream triggers remain less explored. In this study, we conducted an extensive analysis of inhibitors targeting various mitochondrial electron transport chain (ETC) complexes to investigate their potential as activators of the PINK1-Parkin pathway. We identified cloflucarban, an antibacterial compound, as a novel pathway activator that simultaneously inhibits mitochondrial complexes III and V, and V. RNA interference (RNAi) confirmed that the dual inhibition of these complexes activates the PINK1-Parkin pathway. Intriguingly, we discovered that albumin, specifically bovine serum albumin (BSA) and human serum albumin (HSA) commonly present in culture media, can hinder carbonyl cyanide m-chlorophenyl hydrazone (CCCP)-induced pathway activation. However, cloflucarban's efficacy remains unaffected by albumin, highlighting its reliability for studying the PINK1-Parkin pathway. This study provides insights into the activation of the upstream PINK1-Parkin pathway and underscores the influence of culture conditions on research outcomes. Cloflucarban emerges as a promising tool for investigating mitochondrial quality control and neurodegenerative diseases.

CURTAIN—A unique web-based tool for exploration and sharing of MS-based proteomics data

To facilitate analysis and sharing of mass spectrometry (MS)-based proteomics data, we created online tools called CURTAIN (https://curtain.proteo.info) and CURTAIN-PTM (https://curtainptm.proteo.info) with an accompanying series of video tutorials (https://www.youtube.com/@CURTAIN-me6hl). These are designed to enable non-MS experts to interactively peruse volcano plots and deconvolute primary experimental data so that replicates can be visualized in bar charts or violin plots and exported in publication-ready format. They also allow assessment of overall experimental quality by correlation matrix and profile plot analysis. After making a selection of protein "hits", the user can analyze known domain structure, AlphaFold predicted structure, reported interactors, relative expression as well as disease links. CURTAIN-PTM permits analysis of all identified PTM sites on protein(s) of interest with selected databases. CURTAIN-PTM also links with the Kinase Library to predict upstream kinases that may phosphorylate sites of interest. We provide examples of the utility of CURTAIN and CURTAIN-PTM in analyzing how targeted degradation of the PPM1H Rab phosphatase that counteracts the Parkinson's LRRK2 kinase impacts cellular protein levels and phosphorylation sites. We also reanalyzed a ubiquitylation dataset, characterizing the PINK1-Parkin pathway activation in primary neurons, revealing data of interest not highlighted previously. CURTAIN and CURTAIN-PTM are free to use and open source, enabling researchers to share and maximize the impact of their proteomics data. We advocate that MS data published in volcano plot format be reported containing a shareable CURTAIN weblink, thereby allowing readers to better analyze and exploit the data.

Mitophagy activation by rapamycin enhances mitochondrial function and cognition in 5×FAD mice

Alzheimer's disease (AD) is the most prevalent form of dementia, characterized by severe mitochondrial dysfunction, which is an intracellular process that is significantly compromised in the early stages of AD. Mitophagy, the selective removal of damaged mitochondria, is a potential therapeutic strategy for AD. Rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, augmented autophagy and mitigated cognitive impairment. Our study revealed that rapamycin enhances cognitive function by activating mitophagy, alleviating neuronal loss, and improving mitochondrial dysfunction in 5 ×FAD mice. Interestingly, the neuroprotective effect of rapamycin in AD were negated by treatment with 3-MA, a mitophagy inhibitor. Overall, our findings suggest that rapamycin ameliorates cognitive impairment in 5 ×FAD mice via mitophagy activation and its downstream PINK1-Parkin pathway, which aids in the clearance of amyloid-β (Aβ) and damaged mitochondria. This study reveals a novel mechanism involving mitophagy regulation underlying the therapeutic effect of rapamycin in AD. This study provides new insights and therapeutic targets for rapamycin in the treatment of AD. However, there are still some shortcomings in this topic; if we can further knock out the PINK1/Parkin gene in animals or use siRNA technology, we can further confirm the experimental results.