Curcumin promotes exosomes/microvesicles secretion that attenuates lysosomal cholesterol traffic impairment

Ellagic acid and its metabolites urolithins A/B ameliorate most common disease phenotypes in cellular and mouse models for lysosomal storage disorders by enhancing extracellular vesicle secretion

Niemann Pick diseases types A (NPDA) and C (NPDC) are lysosomal storage disorders (LSDs) leading to cognitive impairment, neurodegeneration, and early death. NPDA and NPDC have different genetic origins, being caused by mutations in the acid sphingomyelinase (ASM) or the cholesterol transport protein NPC1, respectively. However, they share a common pathological hallmark in the accumulation of lipids in the endolysosomal compartment. Here, we tested the hypothesis that polyphenols reduce lipid overload in NPD cells by enhancing the secretion of extracellular vesicles (ECVs). We show that among the polyphenols tested, the ellagic acid metabolites, urolithin A and B, were the safest and most efficient in increasing ECV secretion. They reduced levels of accumulating lipids and lysosomal size and permeabilization in cultured bone marrow-derived macrophages and neurons from ASMko and NPC1 mutant mice, which mimic NPDA and NPDC, respectively. Moreover, oral treatment with ellagic acid reduced lipid levels, ameliorated lysosomal alterations, and diminished microglia activation in the brain of NPD mice. These results support the therapeutic value of ECV secretion and polyphenols for NPDs, which may also help treat other LSDs characterized by intracellular lipid overload.

Curcumin Has Beneficial Effects on Lysosomal Alpha-Galactosidase: Potential Implications for the Cure of Fabry Disease

Fabry disease is a lysosomal storage disease caused by mutations in the GLA gene that encodes alpha-galactosidase (AGAL). The disease causes abnormal globotriaosylceramide (Gb3) storage in the lysosomes. Variants responsible for the genotypic spectrum of Fabry disease include mutations that abolish enzymatic activity and those that cause protein instability. The latter can be successfully treated with small molecules that either bind and stabilize AGAL or indirectly improve its cellular activity. This paper describes the first attempt to reposition curcumin, a nutraceutical, to treat Fabry disease. We tested the efficacy of curcumin in a cell model and found an improvement in AGAL activity for 80% of the tested mutant genotypes (four out of five tested). The fold-increase was dependent on the mutant and ranged from 1.4 to 2.2. We produced evidence that supports a co-chaperone role for curcumin when administered with AGAL pharmacological chaperones (1-deoxygalactonojirimycin and galactose). The combined treatment with curcumin and either pharmacological chaperone was beneficial for four out of five tested mutants and showed fold-increases ranging from 1.1 to 2.3 for DGJ and from 1.1 to 2.8 for galactose. Finally, we tested a long-term treatment on one mutant (L300F) and detected an improvement in Gb3 clearance and lysosomal markers (LAMP-1 and GAA). Altogether, our findings confirmed the necessity of personalized therapies for Fabry patients and paved the way to further studies and trials of treatments for Fabry disease.

3,4-Dihydroxybenzalacetone Inhibits the Propagation of Hydrogen Peroxide-Induced Oxidative Effect via Secretory Components from SH-SY5Y Cells

The polyphenol derivative 3,4-dihydroxybenzalacetone (DBL) is the primary antioxidative component of the medicinal folk mushroom Chaga (Inonotus obliquus (persoon) Pilat). In this study, we investigated whether the antioxidative effect of DBL could propagate to recipient cells via secreted components, including extracellular vesicles (EVs), after pre-exposing SH-SY5Y human neuroblastoma cells to DBL. First, we prepared EV-enriched fractions via sucrose density gradient ultracentrifugation using conditioned medium from SH-SY5Y cells exposed to 100 µM hydrogen peroxide (H₂O₂) for 24 h, with and without 1 h of 5 µM DBL pre-treatment. CD63 immuno-dot blot analysis demonstrated that fractions with density of 1.06-1.09 g/cm³ had CD63-like immuno-reactivities. Furthermore, the 2,2-diphenyl-1-picrylhydrazyl assay revealed that the radical scavenging activity of fraction 11 (density of 1.06 g/cm³), prepared after 24-h H₂O₂ treatment, was significantly increased compared to that in the control group (no H₂O₂ treatment). Notably, 1 h of 5 µM DBL pre-treatment or 5 min of heat treatment (100 °C) diminished this effect, although concentrating the fraction by 100 kDa ultrafiltration enhanced it. Overall, the effect was not specific to the recipient cell types. In addition, the uptake of fluorescent Paul Karl Horan-labeled EVs in concentrated fraction 11 was detected in all treatment groups, particularly in the H₂O₂-treated group. The results suggest that cell-to-cell communication via bioactive substances, such as EVs, in conditioned SH-SY5Y cell medium, propagates the H₂O₂-induced radical scavenging effect, whereas pre-conditioning with DBL inhibits it.

Exosome-Containing Extracellular Vesicles Contribute to the Transport of Resveratrol Metabolites in the Bloodstream: A Human Pharmacokinetic Study

Exosomes are extracellular vesicles (EVs) that regulate intercellular signaling by transferring small RNAs, proteins, nucleic acids, lipids, and other metabolites to local or distant organs, including the brain, by crossing the blood–brain barrier. However, the transport of (poly)phenols in human EVs has not yet been described. Therefore, we aimed here to explore (i) whether resveratrol and (or) its derived metabolites are found in the cargo of human plasma exosome-containing EVs (E-EVs), (ii) when this incorporation occurs, and (iii) whether resveratrol intake stimulates the release of E-EVs. Thus, in a pharmacokinetic study, healthy volunteers (n = 16) consumed 1 capsule (420 mg resveratrol) in the evening before attending the clinic and one more capsule on the day of the pharmacokinetics. The plasma and the isolated E-EVs were analyzed using UPLC-ESI-QTOF-MS. Of 17 metabolites in the plasma, 9 were identified in the E-EVs, but not free resveratrol. The kinetic profiles of resveratrol metabolites were similar in the plasma and the E-EVs, a higher metabolite concentration being detected in the plasma than in the E-EVs. However, the plasma/E-EVs ratio decreased in the gut microbial metabolites, suggesting their better encapsulation efficiency in E-EVs. In addition, glucuronide conjugates of resveratrol, dihydroresveratrol, and lunularin were incorporated into the E-EVs more efficiently than their corresponding sulfates despite glucuronides reaching lower plasma concentrations. Notably, more E-EVs were detected 10 h after resveratrol consumption. This exploratory study provides the first evidence that (i) resveratrol metabolites are transported by E-EVs, with a preference for glucuronide vs. sulfates, (ii) the gut microbial metabolites concentration and kinetic profiles are closely similar in E-EVs and plasma, and (iii) resveratrol intake elicits E-EVs secretion. Overall, these results open new research avenues on the possible role of E-EVs in (poly)phenol health effects.

Rottlerin Stimulates Exosome/Microvesicle Release via the Increase of Ceramide Levels Mediated by Ampk in an In Vitro Model of Intracellular Lipid Accumulation

Exosomes/microvesicles originate from multivesicular bodies that allow the secretion of endolysosome components out of the cell. In the present work, we investigated the effects of rottlerin, a polyphenol, on exosome/microvesicle secretion in a model of intracellular lipid trafficking impairment, and elucidated the mechanism of action. In a model of lipid trafficking impairment in C6 glia cells, rottlerin increased ceramide levels, while decreasing hexosylceramide content. This was accompanied by increased exosome/microvesicle secretion, thereby reducing the concentration of lipids in the endolysosomal compartment. The reduction of hexosylceramide levels by rottlerin was attributed to the increase of β-glucosidase (glucosylceramidase) activity, and the effects of rottlerin were abrogated by β-glucosidase inhibitors such as isofagomine D-tartrate and AMP-deoxynojirimycin. Moreover, treatment with ML-266, a potent activator of the β-glucosidase enzyme, recapitulated the effects of rottlerin on the sphingolipid profile and exosome/microvesicle secretion. Finally, inhibition of AMPK (AMP-activated protein kinase) using compound C prevented both exosome/microvesicle secretion and the elimination of endolysosome lipids, which were promoted by rottlerin. The results showed that the decrease in intracellular lipid deposition induced by rottlerin was mediated by β-glucosidase activation and exosome/microvesicle release via the AMPK pathway. Rottlerin consumption could represent an additional health benefit in lysosomal deposition diseases.

Hormone-sensitive lipase deficiency affects the expression of SR-BI, LDLr, and ABCA1 receptors/transporters involved in cellular cholesterol uptake and efflux and disturbs fertility in mouse testis

Hormone-sensitive lipase (HSL) hydrolyse acylglycerols, cholesteryl and retinyl esters. HSL is a key lipase in mice testis, as HSL deficiency results in male sterility. The present work study the effects of the deficiency and lack of HSL on the localization and expression of SR-BI, LDLr, and ABCA1 receptors/transporters involved in uptake and efflux of cholesterol in mice testis, to determine the impact of HSL gene dosage on testis morphology, lipid homeostasis and fertility. The results of this work show that the lack of HSL in mice alters testis morphology and spermatogenesis, decreasing sperm counts, sperm motility and increasing the amount of Leydig cells and lipid droplets. They also show that there are differences in the localization of HSL, SR-BI, LDLr and ABCA1 in HSL+/+, HSL+/- and HSL-/- mice. The deficiency or lack of HSL has effects on protein and mRNA expression of genes involved in lipid metabolisms in mouse testis. HSL-/- testis have augmented expression of SR-BI, LDLr, ABCA1 and LXRβ, a critical sterol sensor that regulate multiple genes involved in lipid metabolism; whereas LDLr expression decreased in HSL+/- mice. Plin2, Abca1 and Ldlr mRNA levels increased; and LXRα (Nr1h3) and LXRβ (Nr1h2) decreased in testis from HSL-/- compared with HSL+/+; with no differences in Scarb1. Together these data suggest that HSL deficiency or lack in mice testis induces lipid homeostasis alterations that affect the cellular localization and expression of key receptors/transporter involved in cellular cholesterol uptake and efflux (SR-BI, LDRr, ABCA1); alters normal cellular function and impact fertility.

Polyphenols and Stem Cells for Neuroregeneration in Parkinson's Disease and Amyotrophic Lateral Sclerosis

Parkinson's disease (PD) and Amyotrophic lateral sclerosis (ALS) are neurological disorders, pathologically characterized by chronic degeneration of dopaminergic neurons and motor neurons respectively. There is still no cure or effective treatment against the disease progression and most of the treatments are symptomatic. The present review offers an overview of the different factors involved in the pathogenesis of these diseases. Subsequently, we focused on the recent advanced studies of dietary polyphenols and stem cell therapies, which have made it possible to slow down the progression of neurodegeneration. To date, stem cells and different polyphenols have been used for the directional induction of neural stem cells into dopaminergic neurons and motor neurons. We have also discussed their involvement in the modulation of different signal transduction pathways and growth factor levels in various in vivo and in vitro studies. Likewise stem cells, polyphenols also exhibit the potential of neuroprotection by their anti-apoptotic, anti-inflammatory, anti-oxidant properties regulating the growth factors levels and molecular signaling events. Overall this review provides a detailed insight into recent strategies that promise the use of polyphenol with stem cell therapy for the possible treatment of PD and ALS.

Curcumin as Prospective Anti-Aging Natural Compound: Focus on Brain

The nutrients and their potential benefits are a new field of study in modern medicine for their positive impact on health. Curcumin, the yellow polyphenolic compound extracted from Curcuma longa species, is widely used in traditional Ayurvedic medicine to prevent and contrast many diseases, considering its antioxidant, immunomodulatory, anti-inflammatory, anti-microbial, cardio-protective, nephron-protective, hepato-protective, anti-neoplastic, and anti-rheumatic proprieties. In recent years, the investigations of curcumin have been focused on its application to aging and age-associated diseases. Aging is a physiological process in which there is a decreasing of cellular function due to internal or external stimuli. Oxidative stress is one of the most important causes of aging and age-related diseases. Moreover, many age-related disorders such as cancer, neuroinflammation, and infections are due to a low-grade chronic systemic inflammation. Curcumin acting on different proteins is able to contrast both oxidative stress than inflammation. In the brain, curcumin is able to modulate inflammation induced by microglia. Finally in brain tumors curcumin is able to reduce tumor growth by inhibition of telomerase activity. This review emphasizes the anti-aging role of curcumin focusing on its mechanism to counteract aging in the brain. Moreover, new formulations to increase the bioavailability of curcumin are discussed.

Extracellular Vesicles in Innate Immune Cell Programming

Extracellular vesicles (EV) are a heterogeneous group of bilipid-enclosed envelopes that carry proteins, metabolites, RNA, DNA and lipids from their parent cell of origin. They mediate cellular communication to other cells in local tissue microenvironments and across organ systems. EV size, number and their biologically active cargo are often altered in response to pathological processes, including infection, cancer, cardiovascular diseases and in response to metabolic perturbations such as obesity and diabetes, which also have a strong inflammatory component. Here, we discuss the broad repertoire of EV produced by neutrophils, monocytes, macrophages, their precursor hematopoietic stem cells and discuss their effects on the innate immune system. We seek to understand the immunomodulatory properties of EV in cellular programming, which impacts innate immune cell differentiation and function. We further explore the possibilities of using EV as immune targeting vectors, for the modulation of the innate immune response, e.g., for tissue preservation during sterile injury such as myocardial infarction or to promote tissue resolution of inflammation and potentially tissue regeneration and repair.

Exosomes as Naturally Occurring Vehicles for Delivery of Biopharmaceuticals: Insights from Drug Delivery to Clinical Perspectives

Exosomes as nanosized vesicles are emerging as drug delivery systems for therapeutics owing to their natural origin, their ability to mediate intercellular communication, and their potential to encapsulate various biological molecules such as proteins and nucleic acids within the lipid bilayer membrane or in the lumen. Exosomes contain endogenous components (proteins, lipids, RNA) that could be used to deliver cargoes to target cells, offering an opportunity to diagnose and treat various diseases. Owing to their ability to travel safely in extracellular fluid and to transport cargoes to target cells with high efficacy, exosomes offer enhanced delivery of cargoes in vivo. However, several challenges related to the stabilization of the exosomes, the production of sufficient amounts of exosomes with safety and efficacy, the efficient loading of drugs into exosomes, the clearance of exosomes from circulation, and the transition from the bench scale to clinical production may limit their development and clinical use. For the clinical use of exosomes, it is important to understand the molecular mechanisms behind the transport and function of exosome vesicles. This review exploits techniques related to the isolation and characterization of exosomes and their drug delivery potential to enhance the therapeutic outcome and stabilization methods. Further, routes of administration, clinical trials, and regulatory aspects of exosomes will be discussed in this review.

One-year dietary supplementation with walnuts modifies exosomal miRNA in elderly subjects

PURPOSE

Epidemiological studies and clinical trials support the association of nut consumption with a lower risk of prevalent non-communicable diseases, particularly cardiovascular disease. However, the molecular mechanisms underlying nut benefits remain to be fully described. MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression and play a pivotal role in health and disease. Exosomes are extracellular vesicles released from cells and mediate intercellular communication. Whether nut consumption modulates circulating miRNAs (c-miRNAs) transported in exosomes is poorly described.

METHODS

Cognitively healthy elderly subjects were randomized to either control (n = 110, abstaining from walnuts) or daily supplementation with walnuts (15% of their total energy, ≈30-60 g/day, n = 101) for 1-year. C-miRNAs were screened in exosomes isolated from 10 samples, before and after supplementation, and identified c-miRNA candidates were validated in the whole cohort. In addition, nanoparticle tracking analysis and lipidomics were assessed in pooled exosomes from the whole cohort.

RESULTS

Exosomal hsa-miR-32-5p and hsa-miR-29b-3p were consistently induced by walnut consumption. No major changes in exosomal lipids, nanoparticle concentration or size were found.

CONCLUSION

Our results provide novel evidence that certain c-miRNAs transported in exosomes are modulated by walnut consumption. The extent to which this finding contributes to the benefits of walnuts deserves further research.

Mediterranean diet enriched in extra-virgin olive oil or nuts modulates circulating exosomal non-coding RNAs

PURPOSE

Exosomes are extracellular vesicles secreted by cells, which can transport different molecules, including nucleic acids. Dietary habits may induce gene regulation through the modulation of exosomal RNAs. We aimed at characterizing exosomal lncRNAs, mRNA and miRNAs modulation after a 1-year adherence to a low-fat diet (LFD) or to Mediterranean-based diets enriched in extra-virgin olive oil (MedDiet + EVOO) or in a mixture of nuts (MedDiet + Nuts).

METHODS

Plasma samples were collected, at baseline and after 1 year of dietary interventions, from 150 participants included in the PREDIMED study (Reus Center). LncRNAs, mRNAs and miRNAs were isolated from plasma exosomes and screened. RT-qPCR validation was performed for miRNAs.

RESULTS

Compared with LFD, 413 lncRNAs and 188 mRNAs, and 476 lncRNAs and 235 mRNAs were differentially modulated in response to the MedDiet + EVOO and MedDiet + Nuts interventions, respectively. In addition, after 1 year of dietary interventions, 26 circulating miRNAs were identified as differentially expressed between groups. After 1 year of intervention, 11 miRNAs significantly changed in LFD group, while 8 and 21 were modulated in response to the MedDiet enriched with EVOO or nuts, respectively. Bioinformatic analyses of differentially expressed miRNAs and their validated target genes suggest certain metabolic pathways are modulated by LFD (PI3K-Akt and AMPK), MedDiet + EVOO (PI3K-Akt, NF-kappa B, HIF-1, and insulin resistance), and MedDiet-Nuts (FoxO, PI3K-Akt, AMPK, p53 and HIF-1) interventions.

CONCLUSION

Results show that 1-year MedDiet + Nuts and MedDiet + EVOO dietary interventions modulate exosomal RNA content, with the former affecting a higher number of miRNAs. The modulation of exosomal RNAs could help explain how the adherence to a Mediterranean diet may lead to beneficial effects and deserves further investigation.

Exosomes transport trace amounts of (poly)phenols

(Poly)phenols have varied biological activities that may account for the beneficial effects of fruits and vegetables as part of a healthy diet. Although their cellular absorption and their many mechanisms of action have been partly elucidated, their transport through the systemic circulation, other than their binding to albumin, is poorly described. We aimed at determining whether (poly)phenols can be transported by extracellular vesicles. We supplemented rats with a dietary grape seed polyphenol extract (GSPE) and we quantified (poly)phenols and their metabolites at 3 and 7 h post-gavage. After quantitative LC-MS/MS analysis of circulating aglycones, and microbial-derived, or phase II-derived metabolites we recorded a quantitatively very modest transport of (poly)phenols in plasma exosomes when isolated by commercial ultracentrifugation or precipitation kits. Our data suggest that GSPE-derived (poly)phenols are minimally, if at all, transported by exosomes.

Cargo and cell-specific differences in extracellular vesicle populations identified by multiplexed immunofluorescent analysis

Extracellular vesicles (EVs) have been implicated in a wide variety of biological activities, have been implicated in the pathogenesis of numerous diseases, and have been proposed to serve as potential biomarkers of disease in human patients and animal models. However, characterization of EV populations is often performed using methods that do not account for the heterogeneity of EV populations and require comparatively large sample sizes to facilitate analysis. Here, we describe an imaging-based method that allows for the multiplexed characterization of EV populations at the single EV level following centrifugation of EV populations directly onto cover slips, allowing comprehensive analysis of EV populations with relatively small samples. We observe that canonical EV markers are present on subsets of EVs which differ substantially in a producer cell and cargo specific fashion, including differences in EVs containing different HIV-1 proteins previously reported to be incorporated into pathogenic EVs. We also describe a lectin binding assay to interrogate EVs based on their glycan content, which we observe to change in response to pharmacological modulation of secretory autophagy pathways. These studies collectively reveal that a multiplexed analysis of EV populations using fluorescent microscopy can reveal differences in specific EV populations that may be used to understand the biogenesis of specific EV populations and/or to interrogate small subsets of EVs of interest within larger EV populations in biological samples.

Curcumin stimulates exosome/microvesicle release in an in vitro model of intracellular lipid accumulation by increasing ceramide synthesis

Curcumin, a hydrophobic polyphenol found in the rhizome of Curcuma longa, has been shown to reduce intracellular lipid accumulation in mouse models of lysosomal storage diseases such as Niemann-Pick type C. Exosomes are small extracellular vesicles secreted by cells in response to changes in intracellular ceramide composition. Curcumin can induce exosome/microvesicle release in cellular models of lipid deposition; however, the mechanism by which curcumin stimulates this release is unknown. In a model of lipid trafficking impairment in C6 glia cells, we show that curcumin stimulated ceramide synthesis by increasing the intracellular concentration of ceramide-dihydroceramide. Ceramide overload increased exosome/microvesicle secretion 10-fold, thereby reducing the concentration of lipids in the endolysosomal compartment. These effects were blocked by inhibitors of serine palmitoyltransferase (myriocin) and ceramide synthase (fumonisin B1). It is concluded that the decrease in intracellular lipid deposition induced by curcumin is mediated by increased ceramide synthesis and exosome/microvesicle release. This action may represent an additional health benefit of curcumin.

Antidiabetic Properties of Curcumin I: Evidence from In Vitro Studies

Type 2 diabetes mellitus (T2DM) is a growing metabolic disease characterized by insulin resistance and hyperglycemia. Current preventative and treatment strategies for T2DM and insulin resistance lack in efficacy resulting in the need for new approaches to prevent and manage/treat the disease better. In recent years, epidemiological studies have suggested that diets rich in fruits and vegetables have beneficial health effects including protection against insulin resistance and T2DM. Curcumin, a polyphenol found in turmeric, and curcuminoids have been reported to have antioxidant, anti-inflammatory, hepatoprotective, nephroprotective, neuroprotective, immunomodulatory and antidiabetic properties. The current review (I of II) summarizes the existing in vitro studies examining the antidiabetic effects of curcumin, while a second (II of II) review summarizes evidence from existing in vivo animal studies and clinical trials focusing on curcumin’s antidiabetic properties.

The Pancreatic Cancer-Initiating Cell Marker CD44v6 Affects Transcription, Translation, and Signaling: Consequences for Exosome Composition and Delivery

Pancreatic cancer-initiating cells (PaCIC) express CD44v6 and Tspan8. A knockdown (kd) of these markers hinders the metastatic capacity, which can be rescued, if the cells are exposed to CIC-exosomes (TEX). Additional evidence that CD44v6 regulates Tspan8 expression prompted us to explore the impact of these PaCIC markers on nonmetastatic PaCa and PaCIC-TEX. We performed proteome, miRNA, and mRNA deep sequencing analyses on wild-type, CD44v6kd, and Tspan8kd human PaCIC and TEX. Database comparative analyses were controlled by qRT-PCR, Western blot, flow cytometry, and confocal microscopy. Transcriptome analysis of CD44 versus CD44v6 coimmunoprecipitating proteins in cells and TEX revealed that Tspan8, several signal-transducing molecules including RTK, EMT-related transcription factors, and proteins engaged in mRNA processing selectively associate with CD44v6 and that the membrane-attached CD44 intracytoplasmic tail supports Tspan8 and NOTCH transcription. Deep sequencing uncovered a CD44v6 contribution to miRNA processing. Due to the association of CD44v6 with Tspan8 in internalization prone tetraspanin-enriched membrane domains (TEM) and the engagement of Tspan8 in exosome biogenesis, most CD44v6-dependent changes were transferred into TEX such that the input of CD44v6 to TEX activities becomes largely waved in both a CD44v6kd and a Tspan8kd. Few differences between CD44v6kd- and Tspan8kd-TEX rely on CD44v6 being also recovered in non-TEM derived TEX, highlighting distinct TEX delivery from individual cells that jointly account for TEX-promoted target modulation. This leads us to propose a model in which CD44v6 strongly supports tumor progression by cooperating with signaling molecules, altering transcription of key molecules, and through its association with the mRNA processing machinery. The association of CD44v6 with Tspan8, which plays a crucial role in vesicle biogenesis, promotes metastases by transferring CD44v6 activities into TEM and TEM-independently derived TEX. Further investigations of the lead position of CD44v6 in shifting metastasis-promoting activities into CIC-TEX may offer a means of targeting TEX-CD44v6 in therapeutic applications.

Insight into the Role of Extracellular Vesicles in Lysosomal Storage Disorders

Extracellular vesicles (EVs) have received increasing attention over the last two decades. Initially, they were considered as just a garbage disposal tool; however, it has progressively become clear that their protein, nucleic acid (namely miRNA and mRNA), and lipid contents have signaling functions. Besides, it has been established that cells release different types of vesicular structures for which characterization is still in its infancy. Many stress conditions, such as hypoxia, senescence, and oncogene activation have been associated with the release of higher levels of EVs. Further, evidence has shown that autophagic–lysosomal pathway abnormalities also affect EV release. In fact, in neurodegenerative diseases characterized by the accumulation of toxic proteins, although it has not become clear to what extent the intracellular storage of undigested materials itself has beneficial/adverse effects, these proteins have also been shown to be released extracellularly via EVs. Lysosomal storage disorders (LSDs) are characterized by accumulation of undigested substrates within the endosomal–lysosomal system, due either to genetic mutations in lysosomal proteins or to treatment with pharmacological agents. Here, we review studies investigating the role of lysosomal and autophagic dysfunction on the release of EVs, with a focus on studies exploring the release of EVs in LSD models of both genetic and pharmacological origin. A better knowledge of EV-releasing pathways activated in lysosomal stress conditions will provide information on the role of EVs in both alleviating intracellular storage of undigested materials and spreading the pathology to the neighboring tissue.

Carnosine induces intestinal cells to secrete exosomes that activate neuronal cells

Recently, we showed that imidazole dipeptide such as carnosine contained abundantly in chicken breast meat improves brain function in a double-blind randomized controlled trial. However, the underlying molecular mechanisms remain unknown. Here, we investigated whether carnosine activates intestinal epithelial cells and induces the secretion of factors that activate brain function. We focused on exosomes derived from intestinal epithelial cells as mediators of brain-gut interaction. Results showed that exosomes derived from Caco-2 cells treated with carnosine significantly induced neurite growth in SH-SY5Y cells. To clarify the molecular basis of this finding, we performed integrated analysis of microRNAs (miRNAs) with altered expression in exosomes in response to carnosine treatment and mRNAs with altered expression in target cells in response to exosome treatment to identify related miRNAs and their target genes. The combination of miR-6769-5p and its target gene ATXN1 was found to be involved in the exosome-induced activation of neuronal cells.

First-Generation Antipsychotic Haloperidol Alters the Functionality of the Late Endosomal/Lysosomal Compartment in Vitro

First- and second-generation antipsychotics (FGAs and SGAs, respectively), have the ability to inhibit cholesterol biosynthesis and also to interrupt the intracellular cholesterol trafficking, interfering with low-density lipoprotein (LDL)-derived cholesterol egress from late endosomes/lysosomes. In the present work, we examined the effects of FGA haloperidol on the functionality of late endosomes/lysosomes in vitro. In HepG2 hepatocarcinoma cells incubated in the presence of 1,1'-dioctadecyl-3,3,3,3'-tetramethylindocarbocyanineperchlorate (DiI)-LDL, treatment with haloperidol caused the enlargement of organelles positive for late endosome markers lysosome-associated membrane protein 2 (LAMP-2) and LBPA (lysobisphosphatidic acid), which also showed increased content of both free-cholesterol and DiI derived from LDL. This indicates the accumulation of LDL-lipids in the late endosomal/lysosomal compartment caused by haloperidol. In contrast, LDL traffic through early endosomes and the Golgi apparatus appeared to be unaffected by the antipsychotic as the distribution of both early endosome antigen 1 (EEA1) and coatomer subunit β (β-COP) were not perturbed. Notably, treatment with haloperidol significantly increased the lysosomal pH and decreased the activities of lysosomal protease and β-d-galactosidase in a dose-dependent manner. We conclude that the alkalinization of the lysosomes' internal milieu induced by haloperidol affects lysosomal functionality.

Curcumin Mitigates the Intracellular Lipid Deposit Induced by Antipsychotics In Vitro

SCOPE

First- and second-generation antipsychotics (FGAs and SGAs, respectively), both inhibit cholesterol biosynthesis and impair the intracellular cholesterol trafficking, leading to lipid accumulation in the late endosome/lysosome compartment. In this study we examined if curcumin, a plant polyphenol that stimulates exosome release, can alleviate antipsychotic-induced intracellular lipid accumulation.

METHODS

HepG2 hepatocarcinoma cells were treated with antipsychotics or placebo and DiI-labelled LDL for 18 h and then exposed to curcumin for the last 2 h. Cells and media were collected separately and used for biochemical analyses, electron microscopy and immunocytochemistry. Exosomes were isolated from the incubation medium by ultracentrifugation.

RESULTS

Curcumin treatment reduced the number of heterolysosomes and shifted their subcellular localization to the periphery, as revealed by electron microscopy, and stimulated the release of lysosomal β-hexosaminidase and exosome markers flotillin-2 and CD63 into the media. The presence of DiI in exosomes released by cells preloaded with DiI-LDL demonstrated the endolysosomal origin of the microvesicles. Furthermore, curcumin increased the secretion of cholesterol as well as LDL-derived DiI and [3H]-cholesterol, in association with a decrease of intracellular lipids. Thus, the disruption of lipid trafficking induced by FGAs or SGAs can be relieved by curcumin treatment. This polyphenol, however, did not mitigate the reduction of cholesterol esterification induced by antipsychotics.

CONCLUSION

Curcumin stimulates exosome release to remove cholesterol (and presumably other lipids) accumulated within the endolysosomal compartment, thereby normalizing intracellular lipid homeostasis. This action may help minimize the adverse metabolic effects of antipsychotic treatment, which should now be evaluated in clinical trials.

Curcumin retunes cholesterol transport homeostasis and inflammation response in M1 macrophage to prevent atherosclerosis

Lipoprotein cholesterol metabolism dysfunction in the arterial wall is a major contributor to atherosclerosis, and excessive lipid intake and failed cholesterol homeostasis may accelerate the atherogenic process. Curcumin exerts multiple effects by alleviating inflammation, hyperlipidemia, and atherosclerosis; however, its role in cholesterol transport homeostasis and its underlying impact on inflammatory M1 macrophages are poorly understood. This work aimed to investigate the effect of curcumin on cholesterol transport, the inflammatory response and cell apoptosis in M1 macrophages. RAW264.7 macrophages (M0) were induced with LPS plus IFN-γ for 12 h to develop a M1 subtype and were then incubated with curcumin at different concentrations (6.25 and 12.5 μmol/L) in the presence or absence of oxLDL. Then, cholesterol influx/efflux and foam cell formation as well as inflammation and apoptosis were evaluated. It was found that curcumin increased cholesterol uptake measured by the Dil-oxLDL binding assay, and simultaneously increased cholesterol efflux carried out by Apo-A1 and HDL in M1 cells. Curcumin further reinforced ox-LDL-induced cholesterol esterification and foam cell formation as determined by Oil Red O and BODIPY staining. Moreover, curcumin dramatically reduced ox-LDL-induced cytokine production such as IL-1β, IL-6 as well as TNF-α and M1 cell apoptosis. We also found that curcumin upregulated CD36 and ABCA1 in M1 macrophages. Curcumin increased PPARγ expression, which in turn promoted CD36 and ABCA1 expression. In conclusion, curcumin may increase the ability of M1 macrophages to handle harmful lipids, thus promoting lipid processing, disposal and removal, which may support cholesterol homeostasis and exert an anti-atherosclerotic effect.

BCM-95 and (2-hydroxypropyl)-β-cyclodextrin reverse autophagy dysfunction and deplete stored lipids in Sap C-deficient fibroblasts

Saposin (Sap) C deficiency is a rare variant form of Gaucher disease caused by impaired Sap C expression or accelerated degradation, and associated with accumulation of glucosylceramide and other lipids in the endo/lysosomal compartment. No effective therapies are currently available for the treatment of Sap C deficiency. We previously reported that a reduced amount and enzymatic activity of cathepsin (Cath) B and Cath D, and defective autophagy occur in Sap C-deficient fibroblasts. Here, we explored the use of two compounds, BCM-95, a curcumin derivative, and (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD), to improve lysosomal function of Sap C-deficient fibroblasts. Immunofluorescence and biochemical studies documented that each compound promotes an increase of the expression levels and activities of Cath B and Cath D, and efficient clearance of cholesterol (Chol) and ceramide (Cer) in lysosomes. We provide evidence that BCM-95 and HP-β-CD enhance lysosomal function promoting autophagic clearance capacity and lysosome reformation. Our findings suggest a novel pharmacological approach to Sap C deficiency directed to treat major secondary pathological aspects in this disorder.

Curcumin increases gelatinase activity in human neutrophils by a p38 mitogen-activated protein kinase (MAPK)-independent mechanism

Curcumin has been found to possess anti-inflammatory activities and neutrophils, key players in inflammation, were previously found to be important targets to curcumin in a few studies. For example, curcumin was found to induce apoptosis in neutrophils by a p38 mitogen-activated protein kinase (MAPK)-dependent mechanism. However, the role of curcumin on the biology of neutrophils is still poorly defined. To study the role of curcumin on neutrophil degranulation and to determine the role of p38 MAPK, human neutrophils were freshly isolated from healthy individuals and incubated in vitro with curcumin. Degranulation was studied at three levels: surface expression of granule markers by flow cytometry; release of matrix metallopeptidase-9 (MMP-9 or gelatinase B) enzyme into supernatants by Western blot; and gelatinase B activity by zymography. Activation of p38 MAPK was studied by monitoring its tyrosine phosphorylation levels by western blot and its role by the utilization of a pharmacological inhibitor. The results indicate that curcumin increased the cell surface expression of CD35 (secretory vesicle), CD63 (azurophilic granules), and CD66b (gelatinase granules) in neutrophils. Also, curcumin increased the release and enzymatic activity of gelatinase B in the extracellular milieu and activated p38 MAP kinase in these cells. However, in contrast to fMLP, curcumin-induced enzymatic activity and secretion of gelatinase B were not reversed by use of a p38 inhibitor. Finally, it was found that curcumin was able to enhance phagocytosis. Taken together, the results here demonstrate that curcumin induced degranulation in human neutrophils and that the increased gelatinase activity is not dependent on p38 MAPK activation. Therefore, degranulation is another human neutrophil function that could be modulated by curcumin, as well as phagocytosis.

Curcumin-primed exosomes mitigate endothelial cell dysfunction during hyperhomocysteinemia

AIM

Exosomes, the nano-units (<200 nm), released from diverse cell types in the extracellular body fluid, possess non-immunogenic property and ability to cross the blood-brain barrier (BBB). Since exosomes carry biological information from their cells of origin, we hypothesize that priming cells with potential therapeutic agents release improved cellular contents through exosomes. Curcumin possesses anti-oxidative and anti-inflammatory properties and provides a promising treatment for cerebral diseases and therefore, the aim of the study is to establish that mouse brain endothelial cells (MBECs) when primed with curcumin (7.5 μM), release an alleviated exosome population that can help recover the endothelial cell (EC) layer permeability.

MAIN METHODS

Homocysteine is a well-known causative factor of BBB disruption; therefore, homocysteine-treated ECs were used as a model of BBB disruption and curcumin-primed exosomes were utilized to check their potential for mitigating EC disruption. MBECs were treated with curcumin and exosomes were isolated by using ultracentrifugation and immunoprecipitation. Expression levels of junction proteins were detected by Western blot and immunocytochemistry assays. Endothelial cell permeability was analyzed with Fluorescein isothiocyanate-Bovine serum albumin (FITC-BSA) leakage assay using transwell permeable supports.

KEY FINDINGS

Exosomes derived from curcumin-treated (primed) cells (CUR-EXO) alleviated oxidative stress, tight junctions (ZO-1, claudin-5, occludin), adherent junction (VE-cadherin) proteins and EC layer permeability induced during EC damage due to high homocysteine levels (hyperhomocysteinemia).

SIGNIFICANCE

In conclusion, the study potentiates the use of CUR-EXO for cerebral diseases where drug delivery is still a challenge. The results also pave the way to novel translational therapies for cerebral diseases by maintaining and establishing therapeutic conservatories via primed exosomes.

Incidence of hypothyroidism after 131I therapy for hyperthyroidism. Relation to pretherapy serum levels of T3, T4 and thyroid antibodies

A correlation is reported between serum levels of triiodothyronine (S-T3) and thyroxine (S-T4) before treatment, as well as levels of thyroid antibodies before treatment, and the development of hypothyroidism following 131I therapy in 86 patients with hyperthyroidism. Patients with marked elevation of S-T3 or S-T4 had demonstrable antibodies to thyroid cytoplasmic antigen more often than those with normal or moderately elevated levels, and patients with markedly elevated levels of S-T3 also had a higher incidence of hypothyroidism after treatment. Patients with nodular thyroid glands and with markedly elevated levels of S-T3 required a larger number of 131I doses before no signs of hyperthyroidism persisted in comparison to those with moderately elevated levels.