Hypoxia-induced HIF1α activation regulates small extracellular vesicle release in human embryonic kidney cells

High-Yield Bioproduction of Extracellular Vesicles from Stem Cell Spheroids via Millifluidic Vortex Transport

Extracellular vesicles (EVs) are emerging as novel therapeutics, particularly in cancer and degenerative diseases. Nevertheless, from both market and clinical viewpoints, high-yield production methods using minimal cell materials are still needed. Herein, a millifluidic cross-slot chip is proposed to induce high-yield release of biologically active EVs from less than three million cells. Depending on the flow rate, a single vortex forms in the outlet channels, exposing transported cellular material to high viscous stresses. Importantly, the chip accommodates producer cells within their physiological environment, such as human mesenchymal stem cells (hMSCs) spheroids, while facilitating their visualization and individual tracking within the vortex. This precise control of viscous stresses at the spheroid level allows for the release of up to 30000 EVs per cell at a Reynolds number of ≈400, without compromising cellular integrity. Additionally, it reveals a threshold initiating EV production, providing evidence for a stress-dependent mechanism governing vesicle secretion. EVs mass-produced at high Reynolds displayed pro-angiogenic and wound healing capabilities, as confirmed by proteomic and cytometric analysis of their cargo. These distinct molecular signatures of these EVs, compared to those derived from monolayers, underscore the critical roles of the production method and the 3D cellular environment in EV generation.

Lung cancer cell-derived exosomes: progress on pivotal role and its application in diagnostic and therapeutic potential

Lung cancer is frequently detected in an advanced stage and has an unfavourable prognosis. Conventional therapies are ineffective for the treatment of metastatic lung cancer. While certain molecular targets have been identified as having a positive response, the absence of appropriate drug carriers prevents their effective utilization. Lung cancer cell-derived exosomes (LCCDEs) have gained attention for their involvement in the development of cancer, as well as their potential for use in diagnosing, treating, and predicting the outcome of lung cancer. This is due to their biological roles and their inherent ability to transport biomolecules from the donor cells. Lung cancer-associated cell-derived extracellular vesicles (LCCDEVs) have the ability to enhance cell proliferation and metastasis, influence angiogenesis, regulate immune responses against tumours during the development of lung cancer, control drug resistance in lung cancer treatment, and are increasingly recognised as a crucial element in liquid biopsy evaluations for the detection of lung cancer. Therapeutic exosomes, which possess inherent intercellular communication capabilities, are increasingly recognised as effective vehicles for targeted drug delivery in precision medicine for tumours. This is due to their exceptional biocompatibility, minimal immunogenicity, low toxicity, prolonged circulation in the bloodstream, biodegradability, and ability to traverse different biological barriers. Currently, multiple studies are being conducted to create new means of diagnosing and predicting outcomes using LCCDEs, as well as to develop techniques for utilizing exosomes as effective carriers for medication delivery. This paper provides an overview of the current state of lung cancer and the wide range of applications of LCCDEs. The encouraging findings and technologies suggest that the utilization of LCCDEs holds promise for the clinical treatment of lung cancer patients.

Hypoxia Pathways in Parkinson's Disease: From Pathogenesis to Therapeutic Targets

The human brain is highly dependent on oxygen, utilizing approximately 20% of the body's oxygen at rest. Oxygen deprivation to the brain can lead to loss of consciousness within seconds and death within minutes. Recent studies have identified regions of the brain with spontaneous episodic hypoxia, referred to as "hypoxic pockets". Hypoxia can also result from impaired blood flow due to conditions such as heart disease, blood clots, stroke, or hemorrhage, as well as from reduced oxygen intake or excessive oxygen consumption caused by factors like low ambient oxygen, pulmonary diseases, infections, inflammation, and cancer. Severe hypoxia in the brain can manifest symptoms similar to Parkinson's disease (PD), including cerebral edema, mood disturbances, and cognitive impairments. Additionally, the development of PD appears to be closely associated with hypoxia and hypoxic pathways. This review seeks to investigate the molecular interactions between hypoxia and PD, emphasizing the pathological role of hypoxic pathways in PD and exploring their potential as therapeutic targets.

Stress-induced extracellular vesicles: insight into their altered proteomic composition and probable physiological role in cancer

EVs (extracellular vesicles) are phospholipid bilayer vesicles that can be released by both prokaryotic and eukaryotic cells in normal as well as altered physiological conditions. These vesicles also termed as signalosomes, possess a distinctive cargo comprising nucleic acids, proteins, lipids, and metabolites, enabling them to play a pivotal role in both local and long-distance intercellular communication. The composition, origin, and release of EVs can be influenced by different physiological conditions and a variety of stress factors, consequently affecting the contents carried within these vesicles. Therefore, identifying the modified contents of EVs can provide valuable insights into their functional role in stress-triggered communication. Particularly, this is important when EVs released from tumor microenvironment are investigated for their role in the development and dissemination of cancer. This review article emphasizes the importance of differential EV shedding and altered proteomic content in response to reduced oxygen concentration, altered levels of glucose and glutamine, pH variations, oxidative stress and Ca2+ ion concertation and it is subsequent effects on the behavior of recipient cells.

Extracellular Vesicles from Adipose Tissue-Derived Stromal Cells Stimulate Angiogenesis in a Scaffold-Dependent Fashion

BACKGROUND

The extracellular vesicles (EVs) secreted by adipose tissue-derived stromal cells (ASC) are microenvironment modulators in tissue regeneration by releasing their molecular cargo, including miRNAs. However, the influence of ASC-derived extracellular vesicles (ASC-EVs) on endothelial cells (ECs) and vascularisation is poorly understood. The present study aimed to determine the pro-angiogenic effects of ASC-EVs and explore their miRNA profile.

METHODS

EVs were isolated from normoxic and hypoxic cultured ASC conditioned culture medium. The miRNA expression profile was determined by miRseq, and EV markers were determined by Western blot and immunofluorescence staining. The uptake dynamics of fluorescently labelled EVs were monitored for 24 h. ASC-EVs' pro-angiogenic effect was assessed by sprouting ex vivo rat aorta rings in left ventricular-decellularized extracellular matrix (LV dECM) hydrogel or basement membrane hydrogel (Geltrex®).

RESULTS

ASC-EVs augmented vascular network formation by aorta rings. The vascular network topology and stability were influenced in a hydrogel scaffold-dependent fashion. The ASC-EVs were enriched for several miRNA families/clusters, including Let-7 and miR-23/27/24. The miRNA-1290 was the highest enriched non-clustered miRNA, accounting for almost 20% of all reads in hypoxia EVs.

CONCLUSION

Our study revealed that ASC-EVs augment in vitro and ex vivo vascularisation, likely due to the enriched pro-angiogenic miRNAs in EVs, particularly miR-1290. Our results show promise for regenerative and revascularisation therapies based on ASC-EV-loaded ECM hydrogels.

Regulation of Cancer-Associated miRNAs Expression under Hypoxic Conditions

Solid tumors frequently experience hypoxia or low O2 levels. In these conditions, hypoxia-inducible factor 1 alpha (HIF-1α) is activated and acts as a transcription factor that regulates cancer cell adaptation to O2 and nutrient deprivation. HIF-1α controls gene expression associated with various signaling pathways that promote cancer cell proliferation and survival. MicroRNAs (miRNAs) are 22-nucleotide noncoding RNAs that play a role in various biological processes essential for cancer progression. This review presents an overview of how hypoxia regulates the expression of multiple miRNAs in the progression of cancer cells.

Mesenchymal stem cell‐derived extracellular vesicles: Recent therapeutics and targeted drug delivery advances

The targeted drug delivery field is rapidly advancing, focusing on developing biocompatible nanoparticles that meet rigorous criteria of non‐toxicity, biocompatibility, and efficient release of encapsulated molecules. Conventional synthetic nanoparticles (SNPs) face complications such as elevated immune responses, complex synthesis methods, and toxicity, which restrict their utility in therapeutics and drug delivery. Extracellular vesicles (EVs) have emerged as promising substitutes for SNPs, leveraging their ability to cross biological barriers, biocompatibility, reduced toxicity, and natural origin. Notably, mesenchymal stem cell‐derived EVs (MSC‐EVs) have garnered much curiosity due to their potential in therapeutics and drug delivery. Studies suggest that MSC‐EVs, the central paracrine contributors of MSCs, replicate the therapeutic effects of MSCs. This review explores the characteristics of MSC‐EVs, emphasizing their potential in therapeutics and drug delivery for various diseases, including CRISPR/Cas9 delivery for gene editing. It also delves into the obstacles and challenges of MSC‐EVs in clinical applications and provides insights into strategies to overcome the limitations of biodistribution and target delivery.

Expression profiles and gene set enrichment analysis of the transcriptomes from the cancer tissue, white adipose tissue and paracancer tissue with colorectal cancer

Background

Colorectal cancer (CRC) is one of the most common cancers worldwide and is related to diet and obesity. Currently, crosstalk between lipid metabolism and CRC has been reported; however, the specific mechanism is not yet understood. In this study, we screened differentially expressed long non-coding RNAs (lncRNAs) and mRNAs from primary cancer, paracancer, and white adipose tissue of CRC patients. We screened and analyzed the genes differentially expressed between primary and paracancer tissue and between paracancer and white adipose tissue but not between primary and white adipose tissue. According to the results of the biological analysis, we speculated a lncRNA (MIR503HG) that may be involved in the crosstalk between CRC and lipid metabolism through exosome delivery.

Methods

We screened differentially expressed long non-coding RNAs (lncRNAs) and mRNAs from primary cancer, paracancer, and white adipose tissue of CRC patients. We screened and analyzed the genes differentially expressed between primary and paracancer tissue and between paracancer and white adipose tissue but not between primary and white adipose tissue.

Results

We speculated a lncRNA (MIR503HG) that may be involved in the crosstalk between CRC and lipid metabolism through exosome delivery.

Conclusions

In this study, the findings raise the possibility of crosstalk between lipid metabolism and CRC through the exosomal delivery of lncRNAs.

Purinergic enzymes on extracellular vesicles: immune modulation on the go

An increase in the extracellular concentration of ATP as a consequence of cellular stress or cell death results in the activation of immune cells. To prevent inflammation, extracellular ATP is rapidly metabolized to adenosine, which deploys an anti-inflammatory signaling cascade upon binding to P1 receptors on immune cells. The ectonucleotidases necessary for the degradation of ATP and generation of adenosine are present on the cell membrane of many immune cells, and their expression is tightly regulated under conditions of inflammation. The discovery that extracellular vesicles (EVs) carry purinergic enzyme activity has brought forward the concept of EVs as a new player in immune regulation. Adenosine-generating EVs derived from cancer cells suppress the anti-tumor response, while EVs derived from immune or mesenchymal stem cells contribute to the restoration of homeostasis after infection. Here we will review the existing knowledge on EVs containing purinergic enzymes and molecules, and discuss the relevance of these EVs in immune modulation and their potential for therapy.

Functional EPAS1/HIF2A missense variant is associated with hematocrit in Andean highlanders

Hypoxia-inducible factor pathway genes are linked to adaptation in both human and nonhuman highland species. EPAS1, a notable target of hypoxia adaptation, is associated with relatively lower hemoglobin concentration in Tibetans. We provide evidence for an association between an adaptive EPAS1 variant (rs570553380) and the same phenotype of relatively low hematocrit in Andean highlanders. This Andean-specific missense variant is present at a modest frequency in Andeans and absent in other human populations and vertebrate species except the coelacanth. CRISPR-base-edited human cells with this variant exhibit shifts in hypoxia-regulated gene expression, while metabolomic analyses reveal both genotype and phenotype associations and validation in a lowland population. Although this genocopy of relatively lower hematocrit in Andean highlanders parallels well-replicated findings in Tibetans, it likely involves distinct pathway responses based on a protein-coding versus noncoding variants, respectively. These findings illuminate how unique variants at EPAS1 contribute to the same phenotype in Tibetans and a subset of Andean highlanders despite distinct evolutionary trajectories.

Co-culture engineering: a promising strategy for production of engineered extracellular vesicle for osteoarthritis treatment

The therapeutic effects of extracellular vesicles (EVs) have been identified as a significant factor in intercellular communication in different disease treatments, including osteoarthritis (OA). Compared to the conventional approaches in treating OA, EV therapy is a non-invasive and cell-free method. However, improving the yield of EVs and their therapeutic effects are the main challenges for clinical applications. In this regard, researchers are using the EV engineering potential to overcome these challenges. New findings suggest that the co-culture strategy as an indirect EV engineering method efficiently increases EV production and quality. The co-culture of mesenchymal stem cells (MSCs) and chondrocytes has improved their chondrogenesis, anti-inflammatory effects, and regenerative properties which are mediated by EVs. Hence, co-culture engineering by considerable systems could be useful in producing engineered EVs for different therapeutic applications. Here, we review various co-culture approaches, including diverse direct and indirect, 2D and 3D cell cultures, as well as static and dynamic systems. Meanwhile, we suggest and discuss the advantages of combined strategies to achieve engineered EVs for OA treatment.

Inorganic Nanoparticles Change Cancer-Cell-Derived Extracellular Vesicle Secretion Levels and Cargo Composition, Resulting in Secondary Biological Effects

Over the past decades, the medical exploitation of nanotechnology has been largely increasing and finding its way into translational research and clinical applications. Despite their biomedical potential, uncertainties persist regarding the intricate role that nanomaterials may play on altering physiology in healthy and diseased tissues. Extracellular vesicles (EVs) are recognized as an important pathway for intercellular communication and known to be mediators of cellular stress. EVs are currently explored for targeted delivery of therapeutic agents, including nanoformulations, to treat and diagnose cancer or other diseases. Here, we aimed to investigate whether nanomaterials could have a possible impact on EV functionality, their safety, and whether EVs can play a role in nanomaterial toxicity profiles. To evaluate this, the impact of inorganic nanomaterial administration on EVs derived from murine melanoma and human breast cancer cells was tested. Cells were incubated with subtoxic concentrations of 4 different biomedically relevant inorganic nanoparticles (NPs): gold, silver, silicon dioxide, or iron oxide. The results displayed a clear NP and cell-type-dependent effect on increasing or decreasing EV secretion. Furthermore, the expression pattern of several EV-derived miRNAs was significantly changed upon NP exposure, compared to nontreated cells. Detailed pathway analysis and additional studies confirmed that EVs obtained from NP-exposed cells could influence immunological responses and cellular physiology. Together, these data reveal that NPs can have wide-ranging effects which can result in toxicity concerns or enhanced therapeutic potential as a secondary enhanced effect mediated and enhanced by EVs.

Update on current and potential application of extracellular vesicles in kidney transplantation

Kidney transplantation (KT) is the best treatment for end-stage kidney disease. However, early diagnosis of graft injury remains challenging, mainly because of the lack of accurate and noninvasive diagnostic techniques. Improving graft outcomes is equally demanding, as is the development of innovative therapies. Many research efforts are focusing on extracellular vesicles, cellular particles free in each body fluid that have shown promising results as precise markers of damage and potential therapeutic targets in many diseases, including the renal field. In fact, through their receptors and cargo, they act in damage response and immune modulation. In transplantation, they may be used to determine organ quality and aging, the presence of delayed graft function, rejection, and many other transplant-related pathologies. Moreover, their low immunogenicity and safe profile make them ideal for drug delivery and the development of therapies to improve KT outcomes. In this review, we summarize current evidence about extracellular vesicles in KT, starting with their characteristics and major laboratory techniques for isolation and characterization. Then, we discuss their use as potential markers of damage and as therapeutic targets, discussing their promising use in clinical practice as a form of liquid biopsy.

Hypoxic regulation of extracellular vesicles: Implications for cancer therapy

Extracellular vesicles (EVs) play a pivotal role in intercellular communication and have been implicated in cancer progression. Hypoxia, a pervasive hallmark of cancer, is known to regulate EV biogenesis and function. Hypoxic EVs contain a specific set of proteins, nucleic acids, lipids, and metabolites, capable of reprogramming the biology and fate of recipient cells. Enhancing the intrinsic therapeutic efficacy of EVs can be achieved by strategically modifying their structure and contents. Moreover, the use of EVs as drug delivery vehicles holds great promise for cancer treatment. However, various hurdles must be overcome to enable their clinical application as cancer therapeutics. In this review, we aim to discuss the current knowledge on the hypoxic regulation of EVs. Additionally, we will describe the underlying mechanisms by which EVs contribute to cancer progression in hypoxia and outline the progress and limitations of hypoxia-related EV therapeutics for cancer.

Acute Kidney Injury by Ischemia/Reperfusion and Extracellular Vesicles

Acute kidney injury (AKI) is often caused by ischemia-reperfusion injury (IRI). IRI significantly affects kidney metabolism, which elicits pro-inflammatory responses and kidney injury. The ischemia/reperfusion of the kidney is associated with transient high mitochondrial-derived reactive oxygen species (ROS) production rates. Excessive mitochondrial-derived ROS damages cellular components and, together with other pathogenic mechanisms, elicits a range of acute injury mechanisms that impair kidney function. Mitochondrial-derived ROS production also stimulates epithelial cell secretion of extracellular vesicles (EVs) containing RNAs, lipids, and proteins, suggesting that EVs are involved in AKI pathogenesis. This literature review focuses on how EV secretion is stimulated during ischemia/reperfusion and how cell-specific EVs and their molecular cargo may modify the IRI process. Moreover, critical pitfalls in the analysis of kidney epithelial-derived EVs are described. In particular, we will focus on how the release of kidney epithelial EVs is affected during tissue analyses and how this may confound data on cell-to-cell signaling. By increasing awareness of methodological pitfalls in renal EV research, the risk of false negatives can be mitigated. This will improve future EV data interpretation regarding EVs contribution to AKI pathogenesis and their potential as biomarkers or treatments for AKI.

Mitochondrial reactive oxygen species modify extracellular vesicles secretion rate

Extracellular vesicle (EV) secretion rate is stimulated by hypoxia that causes increased reactive oxygen species (ROS) production by the mitochondrial electron transport chain (ETC) and hypoxia-induced factor (HIF)-1 signaling; however, their contribution to the increased EV secretion rate is unknown. We found that the EV marker secretion rate in our EV reporter cell line CD9truc-EGFP was unaffected by the HIF-1α stabilizer roxadustat; yet, ETC stimulation by dichloroacetic acid (DCA) significantly increased EV secretion. The DCA-induced EV secretion was blocked by the antioxidant TEMPO and rotenone, an inhibitor of the ETC's Complex I. Under hypoxic conditions, the limited oxygen reduction impedes the ETC's Complex III. To mimic this, we inhibited Complex III with antimycin A, which increased ROS-dependent EV secretion. The electron transport between Complex I and III is accomplished by coenzyme Q created by the mevalonate pathway and tyrosine metabolites. Blocking an early step in the mevalonate pathway using pitavastatin augmented the DCA-induced EV secretion, and 4-nitrobenzoate-an inhibitor of the condensation of the mevalonate pathway with tyrosine metabolites-increased ROS-dependent EV secretion. Our findings indicate that hypoxia-mimetics targeting the ETC modify EV secretion and that ROS produced by the ETC is a potent stimulus for EV secretion.

Energetic Stress-Induced Metabolic Regulation by Extracellular Vesicles

Recent studies have demonstrated that extracellular vesicles (EVs) serve powerful and complex functions in metabolic regulation and metabolic-associated disease, although this field of research is still in its infancy. EVs are released into the extracellular space from all cells and carry a wide range of cargo including miRNAs, mRNA, DNA, proteins, and metabolites that have robust signaling effects in receiving cells. EV production is stimulated by all major stress pathways and, as such, has a role in both restoring homeostasis during stress and perpetuating disease. In metabolic regulation, the dominant stress signal is a lack of energy due to either nutrient deficits or damaged mitochondria from nutrient excess. This stress signal is termed "energetic stress," which triggers a robust and evolutionarily conserved response that engages major cellular stress pathways, the ER unfolded protein response, the hypoxia response, the antioxidant response, and autophagy. This article proposes the model that energetic stress is the dominant stimulator of EV release with a focus on metabolically important cells such as hepatocytes, adipocytes, myocytes, and pancreatic β-cells. Furthermore, this article will discuss how the cargo in stress-stimulated EVs regulates metabolism in receiving cells in both beneficial and detrimental ways. © 2023 American Physiological Society. Compr Physiol 13:5051-5068, 2023.

Hypoxia promotes EV secretion by impairing lysosomal homeostasis in HNSCC through negative regulation of ATP6V1A by HIF-1α

Tumour cells under hypoxia tend to modulate the number and contents of extracellular vesicles (EVs) to regulate the tumour microenvironment (TME) and thus promote tumour progression. However, the mechanism of how hypoxia influences the secretion of EVs remains to be elucidated. Here, we confirm the increased production of EVs in head and neck squamous cell carcinoma (HNSCC) cells under hypoxia, where endosome-derived EVs are the main subtype affected by insufficient O2 . The accumulation of hypoxia-inducible factor-1α (HIF-1α) under hypoxia directly downregulates the expression of ATP6V1A, which is pivotal to maintain the homeostasis of lysosomes. Subsequently, impaired lysosomal degradation contributes to the reduced fusion of multivesicular bodies (MVBs) with lysosomes and enables the secretion of intraluminal vesicles (ILVs) as EVs. These findings establish a HIF-1α-regulated lysosomal dysfunction-EV release axis and provide an exquisite framework to better understand EV biogenesis.

The effects of intravenous remifentanil on umbilical artery serum-derived exosomes in parturients undergoing epidural anesthesia: a randomized trail

BACKGROUND

Umbilical artery serum-derived exosomes (UEs) serve as messengers for maternal-fetal information exchange and cellular regulation. Intravenous remifentanil could be considered as an effective adjunct to epidural anesthesia in providing a favorable analgesia effect for cesarean section (C-section), but its effects on UEs are currently unknown.

METHODS

From 01/12/2021 to 30/06/2022, eligible parturients scheduled for repeated C-section at the First Affiliated Hospital of Wenzhou Medical University were randomized to receive either an intravenous bolus (0.15 μg/kg) followed by a continuous infusion (0.075 μg/kg/min) of remifentanil or normal saline throughout the procedure. The primary outcome was the number of UEs. Secondary outcomes included the size and protein amount of UEs, the vital signs, visceral pain score, sedation score, maternal satisfaction score, Apgar score, the incidence of neonatal asphyxia, umbilical arterial pH, and the presence of complications.

RESULTS

Nanoparticle tracking analysis indicated similar size of UEs between the two groups, but the number and protein amount of UEs were increased in the remifentanil group  compared to the control group (P < 0.05). In parturients receiving remifentanil, visceral pain scores were decreased, which was accompanied by the increased scores of maternal satisfaction with the anesthetic method (P < 0.05). Other maternal and neonatal outcomes were comparable between the two groups (P > 0.05).

CONCLUSION

The intravenous administration of remifentanil increased the number of UEs in parturients undergoing repeated C-section under epidural anesthesia, with improved birth experience and minimal neonatal complications.

Extracellular Vesicles from Human Umbilical Cord-Derived MSCs Affect Vessel Formation In Vitro and Promote VEGFR2-Mediated Cell Survival

Mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) have emerged as novel tools in regenerative medicine. Angiogenesis modulation is widely studied for the treatment of ischaemic diseases, wound healing, and tissue regeneration. Here, we have shown that EVs from human umbilical cord-derived MSCs can affect VEGFR2 signalling, a master regulator of angiogenesis homeostasis, via altering the phosphorylation of AKT. This translates into an inhibition of apoptosis, promoting exclusively cell survival, but not proliferation, in human microvascular endothelial cells. Interestingly, when comparing EVs from normoxic cells to those obtained from hypoxia (1% O₂) preconditioned cells, hypoxia-derived EVs appear to have a slightly enhanced effect. Furthermore, when studied in a longer term endothelial-fibroblast co-culture angiogenesis model in vitro, both EV populations demonstrated a positive effect on vessel formation, evidenced by increased vessel networks with tubes of significantly larger diameters. Our data reveals that EVs selectively target components of the angiogenic pathway, promoting VEGFR2-mediated cell survival via enhancement of AKT activation. Our data show that EVs are able to enhance specific components of the VEGF signalling pathway and may have therapeutic potential to support endothelial cell survival.

Co-aggregation of MSC/chondrocyte in a dynamic 3D culture elevates the therapeutic effect of secreted extracellular vesicles on osteoarthritis in a rat model

Extracellular vesicles (EVs) have therapeutic effects on osteoarthritis (OA). Some recent strategies could elevate EV's therapeutic properties including cell aggregation, co-culture, and 3D culture. It seems that a combination of these strategies could augment EV production and therapeutic potential. The current study aims to evaluate the quantity of EV yield and the therapeutic effect of EVs harvested from rabbit mesenchymal stem cells (MSCs) aggregates, chondrocyte aggregates, and their co-aggregates in a dynamic 3D culture in a rat osteoarthritis model. MSC and chondrocytes were aggregated and co-aggregated by spinner flasks, and their conditioned medium was collected. EVs were isolated by size exclusion chromatography and characterized in terms of size, morphology and surface markers. The chondrogenic potential of the MSC-ag, Cho-ag and Co-ag EVs on MSC micromass differentiation in chondrogenic media were assessed by qRT-PCR, histological and immunohistochemical analysis. 50 μg of MSC-ag-EVs, Cho-ag-EVs and Co-ag-EVs was injected intra-articularly per knee of OA models established by monoiodoacetate in rats. After 8 weeks follow up, the knee joints were harvested and analyzed by radiographic, histological and immunohistochemical features. MSC/chondrocyte co-aggregation in comparison to MSC or chondrocyte aggregation could increase EV yield during dynamic 3D culture by spinner flasks. Although MSC-ag-, Cho-ag- and Co-ag-derived EVs could induce chondrogenesis similar to transforming growth factor-beta during in vitro study, Co-ag-EV could more effectively prevent OA progression than MSC-ag- and Cho-ag-EVs. Our study demonstrated that EVs harvested from the co-aggregation of MSCs and chondrocytes could be considered as a new therapeutic potential for OA treatment.

Exosome biogenesis: machinery, regulation, and therapeutic implications in cancer

Exosomes are well-known key mediators of intercellular communication and contribute to various physiological and pathological processes. Their biogenesis involves four key steps, including cargo sorting, MVB formation and maturation, transport of MVBs, and MVB fusion with the plasma membrane. Each process is modulated through the competition or coordination of multiple mechanisms, whereby diverse repertoires of molecular cargos are sorted into distinct subpopulations of exosomes, resulting in the high heterogeneity of exosomes. Intriguingly, cancer cells exploit various strategies, such as aberrant gene expression, posttranslational modifications, and altered signaling pathways, to regulate the biogenesis, composition, and eventually functions of exosomes to promote cancer progression. Therefore, exosome biogenesis-targeted therapy is being actively explored. In this review, we systematically summarize recent progress in understanding the machinery of exosome biogenesis and how it is regulated in the context of cancer. In particular, we highlight pharmacological targeting of exosome biogenesis as a promising cancer therapeutic strategy.

Hypoxia-Nitric Oxide Axis and the Associated Damage Molecular Pattern in Cutaneous Melanoma

Hypoxia was intensively studied in cancer during the last few decades, being considered a characteristic of the tumor microenvironment. The aim of the study was to evaluate the capacity of tumor cells to adapt to the stress generated by limited oxygen tissue in cutaneous melanoma. We developed a case-control prospective study that included 52 patients with cutaneous melanoma and 35 healthy subjects. We focused on identifying and monitoring hypoxia, the dynamic of nitric oxide (NO) serum metabolites and posttranslational metabolic disorders induced by NO signaling according to the clinical, biological and tumoral characteristics of the melanoma patients. Our study showed high levels of hypoxia-inducible factor-1a (HIF-1a) and hypoxia-inducible factor-2a (HIF-2a) in the melanoma patients. Hypoxia-inducible factors (HIFs) control the capacity of tumor cells to adapt to low levels of oxygen. Hypoxia regulated the nitric oxide synthase (NOS) expression and activity. In the cutaneous melanoma patients, disorders in NO metabolism were detected. The serum levels of the NO metabolites were significantly higher in the melanoma patients. NO signaling influenced the tumor microenvironment by modulating tumoral proliferation and sustaining immune suppression. Maintaining NO homeostasis in the hypoxic tumoral microenvironment could be considered a future therapeutic target in cutaneous melanoma.

Strategies to Convert Cells into Hyaline Cartilage: Magic Spells for Adult Stem Cells

Damaged hyaline cartilage gradually decreases joint function and growing pain significantly reduces the quality of a patient's life. The clinically approved procedure of autologous chondrocyte implantation (ACI) for treating knee cartilage lesions has several limits, including the absence of healthy articular cartilage tissues for cell isolation and difficulties related to the chondrocyte expansion in vitro. Today, various ACI modifications are being developed using autologous chondrocytes from alternative sources, such as the auricles, nose and ribs. Adult stem cells from different tissues are also of great interest due to their less traumatic material extraction and their innate abilities of active proliferation and chondrogenic differentiation. According to the different adult stem cell types and their origin, various strategies have been proposed for stem cell expansion and initiation of their chondrogenic differentiation. The current review presents the diversity in developing applied techniques based on autologous adult stem cell differentiation to hyaline cartilage tissue and targeted to articular cartilage damage therapy.