The Potential Use of Mitochondrial Extracellular Vesicles as Biomarkers or Therapeutical Tools

Mitochondria in aging and age-associated diseases

Mitochondria, essential for cellular energy, are crucial in neurodegenerative disorders (NDDs) and their age-related progression. This review highlights mitochondrial dynamics, mitovesicles, homeostasis, and organelle communication. We examine mitochondrial impacts from aging and NDDs, focusing on protein aggregation and dysfunction. Prospective therapeutic approaches include enhancing mitophagy, improving respiratory chain function, maintaining calcium and lipid balance, using microRNAs, and mitochondrial transfer to protect function. These strategies underscore the crucial role of mitochondrial health in neuronal survival and cognitive functions, offering new therapeutic opportunities.

HSP90 N-terminal inhibition promotes mitochondria-derived vesicles related metastasis by reducing TFEB transcription via decreased HSP90AA1-HCFC1 interaction in liver cancer

Cancer cells compensate with increasing mitochondria-derived vesicles (MDVs) to maintain mitochondrial homeostasis, when canonical MAP1LC3B/LC3B (microtubule associated protein 1 light chain 3 beta)-mediated mitophagy is lacking. MDVs promote the transport of mitochondrial components into extracellular vesicles (EVs) and induce tumor metastasis. Although HSP90 (heat shock protein 90) chaperones hundreds of client proteins and its inhibitors suppress tumors, HSP90 inhibitors-related chemotherapy is associated with unexpected metastasis. Herein, we find that HSP90 inhibitor causes mitochondrial damage but stimulates the low LC3-induced MDVs and the release of MDVs-derived EVs. However, why LC3 decreases and what is the transcriptional regulatory mechanism of MDVs formation under HSP90 inhibition remain unknown. Because TFEB (transcription factor EB) is the most important mitophagy transcription factor, and the HSP90 client HCFC1 (host cell factor C1) regulates TFEB transcription, there should be a hidden connection between TFEB, HCFC1 and HSP90 in MDVs formation. Our results support the idea that HSP90 N-terminal inhibition reduces TFEB transcription via decreased HSP90AA1-HCFC1 interaction, which prevents HCFC1 from binding to the TFEB proximal promoter region. Decreased TFEB transcription and consequently reduced LC3, ultimately promoted MDVs formation. Blocking MDVs formation with the microtubule inhibitor nocodazole (NOC) activates the HCFC1-TFEB-LC3 axis, weakens HSP90 inhibitors-induced MDVs and the release of MDVs-derived EVs, inhibits the growth of tumor cell spheres and primary liver tumors, and reduces the extravasation of cancer cells to secondary metastatic sites. Taken together, these data suggest that combination therapy should be used to reduce the metastatic risk of low TFEB-triggered-MDVs formation caused by HSP90 inhibitors.Abbreviation: ACIs: ATP-competitive inhibitors; BaFA1: bafilomycin A1; CCCP: carbonyl cyanide 3-chlorophenylhydrazone; ChIP: chromatin immunoprecipitation; CHX: cycloheximide; CTD: C-terminal domain; EVs: extracellular vesicles; HCFC1: host cell factor C1; HSP90: heat shock protein 90; ILVs: intralumenal vesicles; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MD: middle domain; MDVs: mitochondria-derived vesicles; MQC: mitochondrial quality control; ΔΨm: mitochondrial membrane potential; MVBs: multivesicular bodies; NB: novobiocin; TEM: transmission electron microscopy; TFEB: transcription factor EB; TFs: transcription factors. NOC: nocodazole; NTD: N-terminal nucleotide binding domain; OCR: oxygen consumption rate; RFP: red fluorescent protein; ROS: reactive oxygen species; STA9090: Ganetespib; VPS35: VPS35 retromer complex component.

"Whole genome bisulfite sequencing of serum extracellular vesicle DNA identifies alterations in mitochondrial DNA methylation in early onset preeclampsia"

Early-onset preeclampsia (EOPE) is a serious pregnancy complication. Understanding its underlying mechanisms could lead to improved diagnosis and management. Genome-wide DNA methylation changes in circulating Extracellular Vesicle DNA (EV-DNA) from women with EOPE could serve as a non-invasive approach to identify key regions and genes that could serve as biomarkers to understand placental pathophysiology. In this case-control study, serum extracellular vesicles were isolated from 3rd trimester pregnant women and characterized using Nanoparticle Tracking Analysis and Transmission Electron Microscopy. The circulating EV-DNA samples were subjected to Whole Genome Bisulfite Sequencing analysis (WGBS) to identify differentially methylated CpGs (DMCs) sites in EOPE cases compared to control. A total of 154 DMCs were identified in EV-DNA, of which 131 were hypomethylated and 23 were hypermethylated. Majority of DMCs were of mitochondrial origin. Previously, it has been reported that oxidative stress, decreased trophoblast differentiation, and invasion are linked to preeclampsia pathogenesis and are related to mitochondrial dysfunction. Therefore, DMCs of the mitochondrial genes like MT-ND1, MT-ND4, MT-CO2, MT-CO3, and MT-RNR1 were selected for validation and showed a similar trend by pyrosequencing. The expression of these genes were also altered in circulating extracellular vesicles. Our study shows changes in the DNA methylation patterns of circulating EV-DNA in women with EOPE. These changes, especially in mitochondrial genes, could lead to mitochondrial dysfunction and contribute EOPE pathogenesis. These findings suggest that these alterations could be explored as non-invasive approach to better understand placental health and improve disease management.

Inter- and intracellular mitochondrial communication: signaling hubs in aging and age-related diseases

Mitochondria are versatile and complex organelles that can continuously communicate and interact with the cellular milieu. Deregulated communication between mitochondria and host cells/organelles has significant consequences and is an underlying factor of many pathophysiological conditions, including the process of aging. During aging, mitochondria lose function, and mitocellular communication pathways break down; mitochondrial dysfunction interacts with mitochondrial dyscommunication, forming a vicious circle. Therefore, strategies to protect mitochondrial function and promote effective communication of mitochondria can increase healthy lifespan and longevity, which might be a new treatment paradigm for age-related disorders. In this review, we comprehensively discuss the signal transduction mechanisms of inter- and intracellular mitochondrial communication, as well as the interactions between mitochondrial communication and the hallmarks of aging. This review emphasizes the indispensable position of inter- and intracellular mitochondrial communication in the aging process of organisms, which is crucial as the cellular signaling hubs. In addition, we also specifically focus on the status of mitochondria-targeted interventions to provide potential therapeutic targets for age-related diseases.

Immune System-Related Plasma Pathogenic Extracellular Vesicle Subpopulations Predict Osteoarthritis Progression

Certain molecules found on the surface or within the cargo of extracellular vesicles (EVs) are linked to osteoarthritis (OA) severity and progression. We aimed to identify plasma pathogenic EV subpopulations that can predict knee radiographic OA (rOA) progression. We analyzed the mass spectrometry-based proteomic data of plasma EVs and synovial fluid (SF) EVs from knee OA patients (n = 16, 50% female). The identified surface markers of interest were further evaluated in plasma EVs from an independent cohort of knee OA patients (n = 30, 47% female) using flow cytometry. A total of 199 peptides with significant correlation between plasma and SF EVs were identified. Of these, 41.7% were linked to immune system processes, 15.5% to inflammatory responses, and 16.7% to the complement system. Crucially, five previously identified knee rOA severity-indicating surface markers-FGA, FGB, FGG, TLN1, and AMBP-were confirmed on plasma EV subpopulations in an independent cohort. These markers' baseline frequencies on large plasma EVs predicted rOA progression with an AUC of 0.655-0.711. Notably, TLN1 was expressed in OA joint tissue, whereas FGA, FGB, FGG, and AMBP were predominantly liver derived. These surface markers define specific pathogenic EV subpopulations, offering potential OA prognostic biomarkers and novel therapeutic targets for disease modification.

Role of mitochondria in reno-cardiac diseases: A study of bioenergetics, biogenesis, and GSH signaling in disease transition

Acute kidney injury (AKI) and chronic kidney disease (CKD) are global health burdens with rising prevalence. Their bidirectional relationship with cardiovascular dysfunction, manifesting as cardio-renal syndromes (CRS) types 3 and 4, underscores the interconnectedness and interdependence of these vital organ systems. Both the kidney and the heart are critically reliant on mitochondrial function. This organelle is currently recognized as a hub in signaling pathways, with emphasis on the redox regulation mediated by glutathione (GSH). Mitochondrial dysfunction, including impaired bioenergetics, redox, and biogenesis pathways, are central to the progression of AKI to CKD and the development of CRS type 3 and 4. This review delves into the metabolic reprogramming and mitochondrial redox signaling and biogenesis alterations in AKI, CKD, and CRS. We examine the pathophysiological mechanisms involving GSH redox signaling and the AMP-activated protein kinase (AMPK)-sirtuin (SIRT)1/3-peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α) axis in these conditions. Additionally, we explore the therapeutic potential of GSH synthesis inducers in mitigating these mitochondrial dysfunctions, as well as their effects on inflammation and the progression of CKD and CRS types 3 and 4.

Mitochondrial Extracellular Vesicles: A Promising Avenue for Diagnosing and Treating Lung Diseases

Mitochondria, pivotal organelles governing cellular biosynthesis, energy metabolism, and signal transduction, maintain dynamic equilibrium through processes such as biogenesis, fusion, fission, and mitophagy. Growing evidence implicates mitochondrial dysfunction in a spectrum of respiratory diseases including acute lung injury/acute respiratory distress syndrome, bronchial asthma, pulmonary fibrosis, chronic obstructive pulmonary disease, and lung cancer. Consequently, identifying methods capable of ameliorating damaged mitochondrial function is crucial for the treatment of pulmonary diseases. Extracellular vesicles (EVs), nanosized membrane vesicles released by cells into the extracellular space, facilitate intercellular communication by transferring bioactive substances or signals between cells or organs. Recent studies have identified abundant mitochondrial components within specific subsets of EVs, termed mitochondrial extracellular vesicles (mitoEVs), whose contents and compositions vary with disease progression. Moreover, mitoEVs have demonstrated reparative mitochondrial functions in injured recipient cells. However, a comprehensive understanding of mitoEVs is currently lacking, limiting their clinical translation prospects. This Review explores the biogenesis, classification, functional mitochondrial cargo, and biological effects of mitoEVs, with a focus on their role in pulmonary diseases. Emphasis is placed on their potential as biological markers and innovative therapeutic strategies in pulmonary diseases, offering fresh insights for mechanistic studies and drug development in various pulmonary disorders.

Immune system-related plasma extracellular vesicles in healthy aging

Objectives

To identify age-related plasma extracellular vehicle (EVs) phenotypes in healthy adults.

Methods

EV proteomics by high-resolution mass spectrometry to evaluate EV protein stability and discover age-associated EV proteins (n=4 with 4 serial freeze-thaws each); validation by high-resolution flow cytometry and EV cytokine quantification by multiplex ELISA (n=28 healthy donors, aged 18-83 years); quantification of WI-38 fibroblast cell proliferation response to co-culture with PKH67-labeled young and old plasma EVs. The EV samples from these plasma specimens were previously characterized for bilayer structure, intra-vesicle mitochondria and cytokines, and hematopoietic cell-related surface markers.

Results

Compared with matched exo-EVs (EV-depleted supernatants), endo-EVs (EV-associated) had higher mean TNF-α and IL-27, lower mean IL-6, IL-11, IFN-γ, and IL-17A/F, and similar mean IL-1β, IL-21, and IL-22 concentrations. Some endo-EV and exo-EV cytokine concentrations were correlated, including TNF-α, IL-27, IL-6, IL-1β, and IFN-γ, but not IL-11, IL-17A/F, IL-21 or IL-22. Endo-EV IFN-γ and exo-EV IL-17A/F and IL-21 declined with age. By proteomics and confirmed by flow cytometry, we identified age-associated decline of fibrinogen (FGA, FGB and FGG) in EVs. Age-related EV proteins indicated predominant origins in the liver and innate immune system. WI-38 cells (>95%) internalized similar amounts of young and old plasma EVs, but cells that internalized PKH67-EVs, particularly young EVs, underwent significantly greater cell proliferation.

Conclusion

Endo-EV and exo-EV cytokines function as different biomarkers. The observed healthy aging EV phenotype reflected a downregulation of EV fibrinogen subpopulations consistent with the absence of a pro-coagulant and pro-inflammatory condition common with age-related disease.

The Research Progress of Mitochondrial Transplantation in the Treatment of Mitochondrial Defective Diseases

Mitochondria are double-membrane organelles that are involved in energy production, apoptosis, and signaling in eukaryotic cells. Several studies conducted over the past decades have correlated mitochondrial dysfunction with various diseases, including cerebral ischemia, myocardial ischemia-reperfusion, and cancer. Mitochondrial transplantation entails importing intact mitochondria from healthy tissues into diseased tissues with damaged mitochondria to rescue the injured cells. In this review, the different mitochondrial transplantation techniques and their clinical applications have been discussed. In addition, the challenges and future directions pertaining to mitochondrial transplantation and its potential in the treatment of diseases with defective mitochondria have been summarized.

Immunometabolism, extracellular vesicles and cardiac injury

Recent evidence from our lab and others suggests that metabolic reprogramming of immune cells drives changes in immune cell phenotypes along the inflammatory-to-reparative spectrum and plays a critical role in mediating the inflammatory responses to cardiac injury (e.g. hypertension, myocardial infarction). However, the factors that drive metabolic reprogramming in immune cells are not fully understood. Extracellular vesicles (EVs) are recognized for their ability to transfer cargo such as microRNAs from remote sites to influence cardiac remodeling. Furthermore, conditions such as obesity and metabolic syndrome, which are implicated in the majority of cardiovascular disease (CVD) cases, can skew production of EVs toward pro-inflammatory phenotypes. In this mini-review, we discuss the mechanisms by which EVs may influence immune cell metabolism during cardiac injury and factors associated with obesity and the metabolic syndrome that can disrupt normal EV function. We also discuss potential sources of cardio-protective and anti-inflammatory EVs, such as brown adipose tissue. Finally, we discuss implications for future therapeutics.

Platelet and mitochondrial RNA is decreased in plasma-derived extracellular vesicles in women with preeclampsia-an exploratory study

BACKGROUND

Circulating extracellular vesicles (EVs) are increased in preeclampsia (PE) and are associated with severity and progression. We examined in this exploratory cohort study if the mRNAs and long noncoding RNAs (lncRNAs) in plasma-derived EVs were dysregulated in PE compared to normal pregnancy and display different temporal patterns during gestation.

METHODS

We isolated EVs from plasma at weeks 22-24 and 36-38 in women with and without PE (n=7 in each group) and performed RNA-seq, focusing on mRNAs and lncRNAs. We validated highly expressed mitochondrial and platelet-derived RNAs discovered from central pathways in 60 women with/without PE. We examined further one of the regulated RNAs, noncoding mitochondrially encoded tRNA alanine (MT-TA), in leukocytes and plasma to investigate its biomarker potential and association with clinical markers of PE.

RESULTS

We found abundant levels of platelet-derived and mitochondrial RNAs in EVs. Expression of these RNAs were decreased and lncRNAs increased in EVs from PE compared to without PE. These findings were further validated by qPCR for mitochondrial RNAs MT-TA, MT-ND2, MT-CYB and platelet-derived RNAs PPBP, PF4, CLU in EVs. Decreased expression of mitochondrial tRNA MT-TA in leukocytes at 22-24 weeks was strongly associated with the subsequent development of PE.

CONCLUSIONS

Platelet-derived and mitochondrial RNA were highly expressed in plasma EVs and were decreased in EVs isolated from women with PE compared to without PE. LncRNAs were mostly increased in PE. The MT-TA in leukocytes may be a useful biomarker for prediction and/or early detection of PE.

The Role of Extracellular Vesicles in Aging and Disease

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