Microvesicles from Mesenchymal Stem Cells Overexpressing MiR-34a Ameliorate Renal Fibrosis In Vivo

INTRODUCTION

We recently discovered that microvesicles (MVs)  derived from mesenchymal stem cells (MSCs) overexpressing  miRNA-34a can alleviate experimental kidney injury in mice. In  this study, we further explored the effects of miR34a-MV on renal  fibrosis in the unilateral ureteral obstruction (UUO) models.  Methods. Bone marrow MSCs were modified by lentiviruses  overexpressing miR-34a, and MVs were collected from the  supernatants of MSCs. C57BL6/J mice were divided into control,  unilateral ureteral obstruction (UUO), UUO + MV, UUO + miR-34aMV and UUO + miR-34a-inhibitor-MV groups. MVs were injected  to mice after surgery. The mice were then euthanized on day 7  and 14 of modeling, and renal tissues were collected for further  analyses by Hematoxylin and eosin, Masson's trichrome,  and Immunohistochemical (IHC) staining.  Results. The UUO + MV group exhibited a significantly reduced  degree of renal interstitial fibrosis with inflammatory cell infiltration,  tubular epithelial cell atrophy, and vacuole degeneration compared  with the UUO group. Surprisingly, overexpressing miR-34a enhanced  these effects of MSC-MV on the UUO mice.  Conclusion. Our study demonstrates that miR34a further enhances  the effects of MSC-MV on renal fibrosis in mice through the  regulation of epithelial-to-mesenchymal transition (EMT) and  Notch pathway. miR-34a may be a candidate molecular therapeutic  target for the treatment of renal fibrosis. DOI: 10.52547/ijkd.7673.

Cell-mimicking nanodecoys neutralize SARS-CoV-2 and mitigate lung injury in a non-human primate model of COVID-19

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has grown into a global pandemic, and only a few antiviral treatments have been approved to date. Angiotensin-converting enzyme 2 (ACE2) plays a fundamental role in SARS-CoV-2 pathogenesis because it allows viral entry into host cells. Here we show that ACE2 nanodecoys derived from human lung spheroid cells (LSCs) can bind and neutralize SARS-CoV-2 and protect the host lung cells from infection. In mice, these LSC-nanodecoys were delivered via inhalation therapy and resided in the lungs for over 72 h post-delivery. Furthermore, inhalation of the LSC-nanodecoys accelerated clearance of SARS-CoV-2 mimics from the lungs, with no observed toxicity. In cynomolgus macaques challenged with live SARS-CoV-2, four doses of these nanodecoys delivered by inhalation promoted viral clearance and reduced lung injury. Our results suggest that LSC-nanodecoys can serve as a potential therapeutic agent for treating COVID-19.

Microvesicles derived from human umbilical cord mesenchyme promote M2 macrophage polarization and ameliorate renal fibrosis following partial nephrectomy via hepatocyte growth factor

The intraoperative ischemia in partial nephrectomy (PN) often leads to postoperative renal function impairment and fibrosis, which can be regulated by macrophage polarization. We have previously demonstrated that microvesicles derived from human Wharton's Jelly mesenchymal stromal cells (hWJMSC-MVs) attenuated renal ischemia-induced renal fibrosis and contained a substantial quantity of hepatocyte growth factor (HGF). Herein, we investigated whether MSC-MVs regulate macrophage polarization and ameliorate renal fibrosis following ischemia-PN via transferring HGF. A rat model of ischemia-PN was established by 45 min of left renal ischemia followed by removal of 1/3 upper left kidney. MSC-MVs were injected through the tail vein immediately after ischemia. Renal injury biomarkers were measured and histologic analysis was performed to analyze renal injury. A co-culture model of THP-1 macrophages and MSC-MVs was utilized. The expression of M1 markers and M2 markers were determined to evaluate macrophage polarization. MSC-MV administration significantly ameliorated renal inflammation, lesions, and fibrosis in ischemia-PN rats, and promoted M2 macrophage polarization both in rat remnant renal tissues and LPS-treated THP-1 cells. These effects of MSC-MVs were compromised when HGF expression was downregulated in MSC-MVs. Collectively, MSC-MVs promote M2 macrophage polarization and attenuate renal fibrosis following ischemia-PN via transferring HGF.

Membrane particles from mesenchymal stromal cells reduce the expression of fibrotic markers on pulmonary cells

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a devastating lung disease with limited treatment options in which the telomere shortening is a strong predictive factor of poor prognosis. Mesenchymal stromal cells (MSC) administration is probed in several experimental induced lung pathologies; however, MSC might stimulate fibrotic processes. A therapy that avoids MSC side effects of transformation would be an alternative to the use of living cells. Membranes particles (MP) are nanovesicles artificially generated from the membranes of MSC containing active enzymes involved in ECM regeneration. We aimed to investigate the anti-fibrotic role of MP derived from MSC in an in vitro model of pulmonary fibrosis.

METHODS

Epithelial cells (A549) and lung fibroblasts, from IPF patients with different telomere length, were co-cultured with MP and TGF-β for 48h and gene expression of major pro-fibrotic markers were analyzed.

RESULTS

About 90% of both types of cells effectively took up MP without cytotoxic effects. MP decreased the expression of profibrotic proteins such as Col1A1, Fibronectin and PAI-1, in A549 cells. In fibroblasts culture, there was a different response in the inhibitory effect of MP on some pro-fibrotic markers when comparing fibroblast from normal telomere length patients (FN) versus short telomere length (FS), but both types showed an inhibition of Col1A1, Tenascin-c, PAI-1 and MMP-1 gene expression after MP treatment.

CONCLUSIONS

MP conserve some of the properties attributed to the living MSC. This study shows that MP target lung cells, via which they may have a broad anti-fibrotic effect.

The Multifunctionality of Exosomes; from the Garbage Bin of the Cell to a Next Generation Gene and Cellular Therapy

Exosomes are packaged with a variety of cellular cargo including RNA, DNA, lipids and proteins. For several decades now there has been ongoing debate as to what extent exosomes are the garbage bin of the cell or if these entities function as a distributer of cellular cargo which acts in a meaningful mechanistic way on target cells. Are the contents of exosomes unwanted excess cellular produce or are they selective nucleic acid packaged nanoparticles used to communicate in a paracrine fashion? Overexpressed RNAs and fragments of DNA have been shown to collect into exosomes which are jettisoned from cells in response to particular stimuli to maintain homeostasis suggesting exosomes are functional trash bins of the cell. Other studies however have deciphered selective packaging of particular nucleic acids into exosomes. Nucleic acids packaged into exosomes are increasingly reported to exert transcriptional control on recipient cells, supporting the notion that exosomes may provide a role in signaling and intracellular communication. We survey the literature and conclude that exosomes are multifunctional entities, with a plethora of roles that can each be taken advantage to functionally modulate cells. We also note that the potential utility of developing exosomes as a next generation genetic therapy may in future transform cellular therapies. We also depict three models of methodologies which can be adopted by researchers intending to package nucleic acid in exosomes for developing gene and cell therapy.

Platelet Extracellular Vesicles: Beyond the Blood

Extracellular vesicles (EVs) are a means of cell-to-cell communication and can facilitate the exchange of a broad array of molecules between adjacent or distant cells. Platelets are anucleate cells derived from megakaryocytes and are primarily known for their role in maintaining hemostasis and vascular integrity. Upon activation by a variety of agonists, platelets readily generate EVs, which were initially identified as procoagulant particles. However, as both platelets and their EVs are abundant in blood, the role of platelet EVs in hemostasis may be redundant. Moreover, findings have challenged the significance of platelet-derived EVs in coagulation. Looking beyond hemostasis, platelet EV cargo is incredibly diverse and can include lipids, proteins, nucleic acids, and organelles involved in numerous other biological processes. Furthermore, while platelets cannot cross tissue barriers, their EVs can enter lymph, bone marrow, and synovial fluid. This allows for the transfer of platelet-derived content to cellular recipients and organs inaccessible to platelets. This review highlights the importance of platelet-derived EVs in physiological and pathological conditions beyond hemostasis.

Exosomes Derived from Bone Marrow Mesenchymal Stem Cells as Treatment for Severe COVID-19

This prospective nonrandomized open-label cohort study addresses the safety and efficacy of exosomes (ExoFlo™) derived from allogeneic bone marrow mesenchymal stem cells as treatment for severe COVID-19. During April 2020, ExoFlo was provided to 24 SARS-CoV-2 polymerase chain reaction-positive patients at a single hospital center, all of whom met criteria for severe COVID-19 as well as moderate-to-severe acute respiratory distress syndrome. Patients received a single 15 mL intravenous dose of ExoFlo and were evaluated for both safety and efficacy from days 1 to 14 post-treatment. All safety endpoints were met with no adverse events observed within 72 h of ExoFlo administration. A survival rate of 83% was observed. In total, 17 of 24 (71%) patients recovered, 3 of 24 (13%) patients remained critically ill though stable, and 4 of 24 (16%) patients expired for reasons unrelated to the treatment. Overall, after one treatment, patients' clinical status and oxygenation improved with an average pressure of arterial oxygen to fraction of inspired oxygen ratio (PaO2/FiO2) increase of 192% (P < 0.001). Laboratory values revealed significant improvements in absolute neutrophil count [mean reduction 32% (P value <0.001)] and lymphopenia with average CD3+, CD4+, and CD8+ lymphocyte counts increasing by 46% (P < 0.05), 45% (P < 0.05), and 46% (P < 0.001), respectively. Likewise, acute phase reactants declined, with mean C-reactive protein, ferritin, and D-dimer reduction of 77% (P < 0.001), 43% (P < 0.001), and 42% (P < 0.05), respectively. In conclusion, owing to its safety profile, capacity to restore oxygenation, downregulate cytokine storm, and reconstitute immunity, ExoFlo is a promising therapeutic candidate for severe COVID-19. Future randomized controlled trials (RCTs) are needed to determine ExoFlo therapeutic potential.

Microvesicles isolated from 5-azacytidine-and-resveratrol-treated mesenchymal stem cells for the treatment of suspensory ligament injury in horse-a case report

BACKGROUND

In athlete horses, suspensory ligament (SL) injuries are the most common cause of lameness. Healing of SL injury is still problematic, and even proper rehabilitation and pharmacological therapy do not guarantee returning to the initial performance level. In our previous studies, we have shown that a combination of 5-azacytidine (AZA) and resveratrol (RES) exerts beneficial, rejuvenating effects on metabolic syndrome derived adipose-derived stem cells (ASCs). Thus, in the presented research, we investigate whether not only rejuvenated ASC but also microvesicles (MVsAZA/RES) secreted by them possess enhanced regenerative properties in SL injury.

METHODS

In the presented study, a 6-year-old Dutch Warmblood gelding, working in jumping, was diagnosed with SL injury using ultrasonography, Doppler, real-time elastography and thermography. As a therapeutic strategy, the affected animal was treated with extracellular microvesicles derived from ASC treated with the combination of 5-azacytydine (AZA) and resveratrol (RES) (MVsAZA/RES). RESULTS: First, anti-apoptotic effects of MVsAZA/RES were tested in co-culture with metabolic syndrome derived ASC. The proliferation of cells and expression of pro-apoptotic genes were investigated. Then, MVsAZA/RES were injected directly into the injured SL of the Dutch Warmblood gelding. In vitro assays revealed that MVsAZA/RES enhance the proliferation of ASC and exert an anti-apoptotic effect. In the affected horse, the application of MVsAZA/RES resulted in increased lesion filling and improvement of angiogenesis and elasticity in injured tissue.

CONCLUSIONS

As MVsAZA/RES mimic several of the biological actions exerted by ASC, they have become an alternative for stem cell-based therapies and can be effectively applied for the treatment of SL injury in horses.

Human extracellular microvesicles from renal tubules reverse kidney ischemia-reperfusion injury in rats

Hypoxic acute kidney injury, a major unresolved problem, initiates, or aggravates, renal functional and structural decline. There is no treatment for hypoxic acute renal injury and its sequelae. We tested the hypothesis that human kidney tubular cells, or their extracellular vesicles (exosomes), prevent renal injury when infused intravenously 24 hours after 50 minutes of bilateral renal ischemia in Nude rats. Cells and their exosomes were from harvested human kidneys declined for transplantation. Injections of either cells or exosomes, given after 24 and 48 hours of reperfusion, preserved renal function and structure in both treatment groups. However, exosomes were superior to cells; and maintained renal vascular and epithelial networks, prevented renal oxidant stress, and apoptosis; and restrained activation of pro-inflammatory and pro-fibrogenic pathways. Exosomes worked in 24 hours, consistent with functional rather than regenerative activity. Comprehensive proteomic analysis identified 6152 renal proteins from all cellular compartments; and 628 were altered by ischemia at all cell levels, while 377 were significantly improved by exosome infusions. We conclude that renal damage from severe ischemia was broad, and human renal exosomes prevented most protein alterations. Thus, exosomes seem to acutely correct a critical and consequential abnormality during reperfusion. In their absence, renal structure and cells transition to a chronic state of fibrosis and extensive renal cell loss.

Macrophage Immunomodulation: The Gatekeeper for Mesenchymal Stem Cell Derived-Exosomes in Pulmonary Arterial Hypertension?

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by remodeling of the pulmonary arteries, increased pulmonary infiltrates, loss of vascular cross-sectional area, and elevated pulmonary vascular resistance. Despite recent advances in the management of PAH, there is a pressing need for the development of new tools to effectively treat and reduce the risk of further complications. Dysregulated immunity underlies the development of PAH, and macrophages orchestrate both the initiation and resolution of pulmonary inflammation, thus, manipulation of lung macrophage function represents an attractive target for emerging immunomodulatory therapies, including cell-based approaches. Indeed, mesenchymal stem cell (MSC)-based therapies have shown promise, effectively modulating the macrophage fulcrum to favor an anti-inflammatory, pro-resolving phenotype, which is associated with both histological and functional benefits in preclinical models of pulmonary hypertension (PH). The complex interplay between immune system homeostasis and MSCs remains incompletely understood. Here, we highlight the importance of macrophage function in models of PH and summarize the development of MSC-based therapies, focusing on the significance of MSC exosomes (MEx) and the immunomodulatory and homeostatic mechanisms by which such therapies may afford their beneficial effects.

Mesenchymal stromal cell-derived exosome-rich fractionated secretome confers a hepatoprotective effect in liver injury

BACKGROUND

Mesenchymal stromal cells (MSCs) are an attractive therapeutic agent in regenerative medicine. Recently, there has been a paradigm shift from differentiation of MSCs to their paracrine effects at the injury site. Several reports elucidate the role of trophic factors secreted by MSCs toward the repair of injured tissues. We hypothesize that fractionating the MSC secretome will enrich exosomes containing soluble bioactive molecules, improving its therapeutic potential for liver failure.

METHODS

Rat bone marrow MSCs were isolated and the conditioned media filtered, concentrated and ultracentrifuged to generate fractionated secretome. This secretome was characterized for the presence of exosomes and recovery from liver injury assessed in in-vitro liver injury models. The results were further validated in vivo.

RESULTS

Studies on in-vitro liver injury models using acetaminophen and hydrogen peroxide show better cell recovery and reduced cytotoxicity in the presence of fractionated as opposed to unfractionated secretome. Further, the cells showed reduced oxidative stress in the presence of fractionated secretome, suggesting a potential antioxidative effect. These results were further validated in vivo in liver failure models, wherein improved liver regeneration in the presence of fractionated secretome (0.819 ± 0.035) was observed as compared to unfractionated secretome (0.718 ± 0.042).

CONCLUSIONS

The work presented is a proof of concept that fractionating the secretome enriches certain bioactive molecules involved in the repair and recovery of injured liver tissue. Exosome enriched mesenchymal stromal cell-derived fractionated secretome potentiates recovery upon injection in injured liver.

Pathogenic or Therapeutic Extracellular Vesicles in Rheumatic Diseases: Role of Mesenchymal Stem Cell-Derived Vesicles

Extracellular vesicles (EVs) are important mediators of cell-to-cell communication pathways via the transport of proteins, mRNA, miRNA and lipids. There are three main types of EVs, exosomes, microparticles and apoptotic bodies, which are classified according to their size and biogenesis. EVs are secreted by all cell types and their function reproduces that of the parental cell. They are involved in many biological processes that regulate tissue homeostasis and physiopathology of diseases. In rheumatic diseases, namely osteoarthritis (OA) and rheumatoid arthritis (RA), EVs have been isolated from synovial fluid and shown to play pathogenic roles contributing to progression of both diseases. By contrast, EVs may have therapeutic effect via the delivery of molecules that may stop disease evolution. In particular, EVs derived from mesenchymal stem cells (MSCs) reproduce the main functions of the parental cells and therefore represent the ideal type of EVs for modulating the course of either disease. The aim of this review is to discuss the role of EVs in OA and RA focusing on their potential pathogenic effect and possible therapeutic options. Special attention is given to MSCs and MSC-derived EVs for modulating OA and RA progression with the perspective of developing innovative therapeutic strategies.

The secretome of periodontal ligament stem cells from MS patients protects against EAE

Manipulation of stem cells or stem cells-derived secretome has emerged as a novel alternative therapeutic option for multiple sclerosis (MS). Here we show that human periodontal ligament stem cells (hPDLSCs)-derived conditioned medium (hPDLSCs-CM) and purified exosomes/microvesicles (hPDLSCs-EMVs) obtained from Relapsing Remitting (RR)-MS patients and healthy donors block experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, by inducing anti-inflammatory and immunosuppressive effects in spinal cord and spleen, and reverse disease progression by restoring tissue integrity via remyelination in the spinal cord. We show that hPDLSCs-CM and hPDLSCs-EMVs reduce pro-inflammatory cytokines IL-17, IFN-γ, IL-1β, IL-6, TNF-α, and induce anti-inflammatory IL-10. In addition, apoptosis related STAT1, p53, Caspase 3, and Bax expressions were attenuated. Our findings unravel the immunosuppressive effects of hPDLSCs-CM and hPDLSCs-EMVs in EAE mice, and suggest simple alternative autologous source for patient-customized cell-free targeting treatment in MS patients.

Platelet-derived microvesicles are involved in cardio-protective effects of remote preconditioning

The ischemia-protective mechanism of remote precondition has been a mystery for a long time. Little was known about details of the inter-organ cardio-protective. Microvesicles, also known as microparticles (MPs), are small membrane-vesicles budding from the plasma membrane of cell. Recent studies have indicated MPs to be an important messenger in various biological processes. Our research mainly examined the hypothesis that remote ischemic conditioning can attenuate heart infarction in a rat after they were subjected to 30 min ischemia and 180 min reperfusion (I/R) by MPs. MPs were extracted from three groups of rat: 1) healthy rats, 2) healthy rats that underwent hindlimb ischemia-reperfusion preconditioning (RIPC) immediately, 3) healthy rats that underwent RIPC in 6 hours. Isolated MPs were transfused into rats that had undergone I/R without RIPC. The transfusion of MPs from rats that underwent RIPC immediately resulted in an increase in platelet-derived MPs in blood and reduction in infarction size, confirmed by 2-3-5-triphenyltetrazolium chloride staining. We further observed the contractile function in hearts after they were subjected to different treatments. However, no significant difference was observed in transfusion of MPs from rats that underwent RIPC in 6 hours. RIPC induces an increase in MPs, and platelet-derived MPs may confer at least part of the remote protective effect against cardiac ischemic-reperfusion injury.

Angiogenic microvascular endothelial cells release microparticles rich in tissue factor that promotes postischemic collateral vessel formation

OBJECTIVE

Therapeutic angiogenesis is a promising strategy for treating ischemia. Our previous work showed that endogenous endothelial tissue factor (TF) expression induces intracrine signaling and switches-on angiogenesis in microvascular endothelial cells (mECs). We have hypothesized that activated mECs could exert a further paracrine regulation through the release of TF-rich microvascular endothelial microparticles (mEMPs) and induce neovascularization of ischemic tissues.

APPROACH AND RESULTS

Here, we describe for the first time that activated mECs are able to induce reparative neovascularization in ischemic zones by releasing TF-rich microparticles. We show in vitro and in vivo that mEMPs released by both wild-type and TF-upregulated-mECs induce angiogenesis and collateral vessel formation, whereas TF-poor mEMPs derived from TF-silenced mECs are not able to trigger angiogenesis. Isolated TF-bearing mEMPs delivered to nonperfused adductor muscles in a murine hindlimb ischemia model enhance collateral flow and capillary formation evidenced by MRI. TF-bearing mEMPs increase angiogenesis operating via paracrine regulation of neighboring endothelial cells, signaling through the β1-integrin pathway Rac1-ERK1/2-ETS1 and triggering CCL2 (chemokine [C-C motif] ligand 2) production to form new and competent mature neovessels.

CONCLUSIONS

These findings demonstrate that TF-rich mEMPs released by microvascular endothelial cells can overcome the consequences of arterial occlusion and tissue ischemia by promoting postischemic neovascularization and tissue reperfusion.