Bone mesenchymal stem cells ameliorate ischemia/reperfusion-induced damage in renal epithelial cells via microRNA-223

Systems Approaches to Cell Culture-Derived Extracellular Vesicles for Acute Kidney Injury Therapy: Prospects and Challenges

Acute kidney injury (AKI) is a heterogeneous syndrome, comprising diverse etiologies of kidney insults that result in high mortality and morbidity if not well managed. Although great efforts have been made to investigate underlying pathogenic mechanisms of AKI, there are limited therapeutic strategies available. Extracellular vesicles (EV) are membrane-bound vesicles secreted by various cell types, which can serve as cell-free therapy through transfer of bioactive molecules. In this review, we first overview the AKI syndrome and EV biology, with a particular focus on the technical aspects and therapeutic application of cell culture-derived EVs. Second, we illustrate how multi-omic approaches to EV miRNA, protein, and genomic cargo analysis can yield new insights into their mechanisms of action and address unresolved questions in the field. We then summarize major experimental evidence regarding the therapeutic potential of EVs in AKI, which we subdivide into stem cell and non-stem cell-derived EVs. Finally, we highlight the challenges and opportunities related to the clinical translation of animal studies into human patients.

Exosomal miR-223-3p from bone marrow mesenchymal stem cells targets HDAC2 to downregulate STAT3 phosphorylation to alleviate HBx-induced ferroptosis in podocytes

Background: Hepatitis B virus associated-glomerulonephritis (HBV-GN) is one of the major secondary renal diseases in China, and microRNAs (miRNAs) in bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exo) can attenuate HBV-X protein (HBx)-induced ferroptosis in renal podocytes, but the exact mechanism remains unclear. This study aimed to investigate the protective mechanism of miR-223-3p in BMSC-Exo in HBx-induced ferroptosis in podocytes. Methods: The study employed human renal podocyte cells (HPCs), bone marrow-derived mesenchymal stem cells (BMSCs), as well as kidney tissue from C57BL/6 mice and HBx transgenic mice. Initially, the correlation between STAT3 phosphorylation and ferroptosis was authenticated through the administration of signal transducer and activator of transcription 3 (STAT3) phosphorylation inhibitors in both in vivo and in vitro settings. Furthermore, the effect of HDAC2 overexpression on STAT3 phosphorylation was examined. Subsequently, the association between BMSC-Exo carrying miR-223-3p, HDAC2, and the phosphorylation of STAT3 in HPCs ferroptosis and injury induced by HBx was assessed. The interaction between miR-223-3p and HDAC2 was confirmed via RNA immunoprecipitation assay. Various techniques such as cell counting kit-8 assay, western blot, RT-qPCR, immunofluorescence, flow cytometry, lipid peroxidation assay kit, iron assay kit, transmission electron microscopy, and hematoxylin-eosin staining were employed to visualize the extent of HBx-induced podocyte injury and ferroptosis in both in vivo and in vitro. Results: The attenuation of podocyte ferroptosis can be achieved by inhibiting the phosphorylation of STAT3 in podocytes induced by HBx. Conversely, the upregulation of HDAC2 can enhance STAT3 phosphorylation, thereby promoting podocyte ferroptosis. MiR-223-3p was capable of directly exerting negative regulation on HDAC2 expression. BMSC-Exo carrying miR-223-3p can effectively suppress the expression of HDAC2, ultimately leading to reduce HBx-induced ferroptosis in podocytes by targeting HDAC2 with miR-223-3p and downregulating STAT3 phosphorylation. Conclusion: This study evidences the potential of BMSC-Exo mediated delivery of miR-223-3p in mitigating HBx-induced ferroptosis in podocytes, thereby offering a novel therapeutic target and approach for treating HBV-GN and alleviating renal injury.

MicroRNAs as Biomarkers and Therapeutic Targets for Acute Kidney Injury

Acute kidney injury (AKI) is a clinical syndrome where a rapid decrease in kidney function and/or urine output is observed, which may result in the imbalance of water, electrolytes and acid base. It is associated with poor prognosis and prolonged hospitalization. Therefore, an early diagnosis and treatment to avoid the severe AKI stage are important. While several biomarkers, such as urinary L-FABP and NGAL, can be clinically useful, there is still no gold standard for the early detection of AKI and there are limited therapeutic options against AKI. miRNAs are non-coding and single-stranded RNAs that silence their target genes in the post-transcriptional process and are involved in a wide range of biological processes. Recent accumulated evidence has revealed that miRNAs may be potential biomarkers and therapeutic targets for AKI. In this review article, we summarize the current knowledge about miRNAs as promising biomarkers and potential therapeutic targets for AKI, as well as the challenges in their clinical use.

EFFECTS OF MESENCHYMAL STEM CELLS ON POSTRESUSCITATION RENAL AND INTESTINAL INJURIES IN A PORCINE CARDIAC ARREST MODEL

ABSTRACT

Objectives: Systemic ischemia-reperfusion triggered by cardiac arrest (CA) and resuscitation often causes postresuscitation multiple organ injuries. Mesenchymal stem cells (MSCs) have been proven to be a promising treatment for regional renal and intestinal ischemia reperfusion injuries. This study aimed to investigate the effects of MSCs on renal and intestinal injuries after cardiopulmonary resuscitation (CPR) in a porcine CA model. Methods: Twenty-two male pigs were randomly assigned to the sham (n = 6), CA/CPR (n = 8), and CA/CPR + MSC (n = 8) groups. Mesenchymal stem cells were differentiated from human embryonic stem cells and then intravenously administered at a dose of 2.5 × 10 6 /kg at 1.5 and 3 d before the CA/CPR procedure. The experimental model was established by 8 min of untreated CA, followed by 8 min of CPR. Renal and intestinal injuries were evaluated based on the serum levels of creatinine, serum urea nitrogen, intestinal fatty acid-binding protein, and diamine oxidase at 1, 2, 4, and 24 h after resuscitation. At the end of the experiment, pathological damage was determined by cell apoptosis and ferroptosis in the renal and intestinal tissues. Results: During CPR, five pigs in the CA/CPR group and seven pigs in the CA/CPR + MSC group were successfully resuscitated. After resuscitation, the serum levels of creatinine, serum urea nitrogen, intestinal fatty acid-binding protein, and diamine oxidase were significantly increased in the CA/CPR and CA/CPR + MSC groups compared with those in the sham group. However, MSC administration significantly decreased the levels of renal and intestinal injury biomarkers compared with those in the CA/CPR group. Cell apoptosis and ferroptosis, which were indicated by the levels of apoptotic cells, iron deposition, lipid peroxidation, antioxidants, and ferroptosis-related proteins, were observed in renal and intestinal tissues after resuscitation in the CA/CPR and CA/CPR + MSC groups. Nevertheless, both were significantly milder in the CA/CPR + MSC group than in the CA/CPR group. Conclusions: MSC administration was effective in alleviating postresuscitation renal and intestinal injuries possibly through inhibition of cell apoptosis and ferroptosis in a porcine CA model.

RNA-seq reveals the role of miR-223 in alleviating inflammation of bovine mammary epithelial cells

Bovine mammary epithelial cells (bMECs) are involved in the early defense against the invasion of intramammary pathogens and are essential for the health of bovine mammary gland. MicroRNA (MiRNA) is a key factor that regulates cell state and physiological function. In the present study, the transcriptome profiles of miR-223 inhibitor transfection group (miR-223_Inhibitor) and negative control inhibitor transfection group (NC_Inhibitor) within bMECs were detected via the RNA sequencing (RNA-seq) platform. Based on these experiments, the differentially expressed mRNAs (DE-mRNAs) of the miR-223_Inhibitor transfection group were screened, and the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional analyses of DE-mRNAs were performed. The results revealed that compared with the NC_Inhibitor, 224 differentially expressed genes (DEGs) were identified in the miR-223_Inhibitor, including 184 upregulated and 40 downregulated genes. The functional annotation of the above DEGs indicated that some of these genes are involved in the immune response generated by extracellular substance stimulation, regulation of the activity of cytokines and chemokines, and the immune signaling pathways of NF-κB and TNF. Meanwhile, miR-223_inhibitor upregulated the immune key genes IRF1 and NFκBIA, cytokines IL-6 and IL-24, as well as chemokines CXCL3, CXCL5, and CCR6, triggering a signaling cascade response that exacerbated inflammation in bMECs. These results suggested that miR-223 plays an important role in inhibiting the inflammatory response and maintaining the stability of bMECs, and is a potential target for treating mastitis in dairy cows.

Anti-apoptotic effect of HeidihuangWan in renal tubular epithelial cells via PI3K/Akt/mTOR signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Heidihuang Wan (HDHW) is a classic Chinese herbal formula, which was first recorded in the "Suwen Bingji Qiyi Baoming Collection" written by Liu Wansu during the Jin Dynasty (1115-1234 AD). It is commonly used clinically for the treatment of kidney diseases and its curative effect is stable. Previous animal experiments have confirmed that HDHW can effectively improve renal fibrosis. However, the underlying pharmacological mechanism remains unclear.

AIMS OF THIS STUDY

Renal tubular epithelial cell (RTEC) apoptosis is one of the main pathological features of renal fibrosis. This study aimed to observe the effect and underlying mechanism of HDHW on the apoptosis of RTECs to further explore the pathological mechanism of HDHW against renal fibrosis.

MATERIALS AND METHODS

We examined the HDHW composition in rat serum. In vitro, we first screened out the optimal intervention concentration of HDHW on RTECs using the MTT assay. Hypoxia/reoxygenation was then used to induce apoptosis of RTECs (H/R-RTECs), which were divided into H/R-RTEC, astragaloside IV (positive control), HDHW, and RTECs groups. After 48 h of drug intervention, apoptosis of RTECs was detected using flow cytometry and protein expression was detected by western blotting. The 5/6 nephrectomy rat model was constructed and divided into the normal control, 5/6 nephrectomy, HDHW, and astragaloside IV groups. After 8 weeks of treatment, TUNEL staining was used to detect cell apoptosis, and western blotting was used to detect protein expression.

RESULTS

HDHW downregulated the expression of pro-apoptotic proteins Bax and Caspase3, up-regulated the expression of anti-apoptotic protein Bcl-2, activated the PI3K/Akt/mTOR signaling pathway, and reversed the early apoptosis of RTECs, thereby resisting the apoptosis of RTECs.

CONCLUSION

HDHW inhibits apoptosis of RTECs by modulating the PI3K/Akt/mTOR signaling pathway. This study provides experimental evidence for the anti-fibrotic effect of HDHW on the kidneys and partially elucidates its pharmacological mechanism of action.

Circulating Extracellular Vesicles in Stroke Patients Treated With Mesenchymal Stem Cells: A Biomarker Analysis of a Randomized Trial

Background:

Mesenchymal stem cells (MSCs) secrete trophic factors and extracellular vesicles (EVs). However, the level and role of EVs after MSC therapy in patients with stroke are unknown. We investigated whether circulating EVs and trophic factors are increased after MSCs and are related to the therapeutic benefits in the STARTING-2 trial (Stem Cell Application Researches and Trials in Neurology-2) participants.

Methods:

In this prospective randomized controlled trial, patients with chronic major stroke were assigned, in a 2:1 ratio, to receive autologous MSC intravenous injection (MSC group, n=39) or standard treatment (control group, n=15) and followed for 3 months. Detailed clinical assessment and neuroplasticity on diffusion tensor image and resting-state functional magnetic resonance imaging were evaluated. Serial samples were collected, before/after MSCs therapy. The primary outcome measure was circulating factors that are associated with the clinical improvement in the Fugl-Meyer Assessment (secondary end point of the trial) and neuroplasticity on diffusion tensor image and resting-state functional magnetic resonance imaging. Additional outcome measures were microRNAs and trophic factors enriched in the plasma EVs, obtained using quantitative polymerase chain reaction and ELISA, respectively.

Results:

Circulating EV levels were increased ≈5-fold (mean±SD, from 2.7×10 9 ±2.2×10 9 to 1.3×10 10 ±1.7×10 10 EVs/mL) within 24 hours after injection of MSCs ( P =0.001). After adjustment of age, sex, baseline stroke severity, and the time interval from stroke onset to treatment, only the EV number was independently associated with improvement in motor function (odds ratio, 5.718 for EV number Log [95% CI, 1.144–28.589]; P =0.034). Diffusion tensor image and resting-state functional magnetic resonance imaging showed that integrity of the ipsilesional corticospinal tract and intrahemispheric motor network were significantly correlated with circulating EV levels, respectively ( P <0.05). MicroRNAs related to neurogenesis/neuroplasticity (eg, microRNA-18a-5p) were significantly increased in circulating EVs after MSC therapy ( P =0.0479). In contrast, trophic factor levels were not changed after MSC therapy.

Conclusions:

This trial is the first to show that treatment of ischemic stroke patients with MSCs significantly increases circulating EVs, which were significantly correlated with improvement in motor function and magnetic resonance imaging indices of plasticity.

Registration:

URL: https://www.clinical trials.gov ; Unique identifier: NCT01716481.

Stem Cell-Derived Extracellular Vesicles as Potential Therapeutic Approach for Acute Kidney Injury

Acute kidney injury is a frequent complication of hospitalized patients and significantly increases morbidity and mortality, worsening costs and length of hospital stay. Despite this impact on healthcare system, treatment still remains only supportive (dialysis). Stem cell-derived extracellular vesicles are a promising option as they recapitulate stem cells properties, overcoming safety issues related to risks or rejection or aberrant differentiation. A growing body of evidence based on pre-clinical studies suggests that extracellular vesicles may be effective to treat acute kidney injury and to limit fibrosis through direct interference with pathogenic mechanisms of vascular and tubular epithelial cell damage. We herein analyze the state-of-the-art knowledge of therapeutic approaches with stem cell-derived extracellular vesicles for different forms of acute kidney injury (toxic, ischemic or septic) dissecting their cytoprotective, regenerative and immunomodulatory properties. We also analyze the potential impact of extracellular vesicles on the mechanisms of transition from acute kidney injury to chronic kidney disease, with a focus on the pivotal role of the inhibition of complement cascade in this setting. Despite some technical limits, nowadays the development of therapies based on stem cell-derived extracellular vesicles holds promise as a new frontier to limit acute kidney injury onset and progression.

Identification of hub genes and transcription factor-miRNA-mRNA pathways in mice and human renal ischemia-reperfusion injury

Background

Renal ischemia-reperfusion injury (IRI) is a disease with high incidence rate in kidney related surgery. Micro RNA (miRNA) and transcription factors (TFs) are widely involved in the process of renal IRI through regulation of their target genes. However, the regulatory relationships and functional roles of TFs, miRNAs and mRNAs in the progression of renal IRI are insufficiently understood. The present study aimed to clarify the underlying mechanism of regulatory relationships in renal IRI.

Methods

Six gene expression profiles were downloaded from Gene Expression Omnibus (GEO). Differently expressed genes (DEGs) and differently expressed miRNAs (DEMs) were identified through RRA integrated analysis of mRNA datasets (GSE39548, GSE87025, GSE52004, GSE71647, and GSE131288) and miRNA datasets (GSE29495). miRDB and TransmiR v2.0 database were applied to predict target genes of miRNA and TFs, respectively. DEGs were applied for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, followed with construction of protein-protein interaction (PPI) network. Then, the TF-miRNA-mRNA network was constructed. Correlation coefficient and ROC analysis were used to verify regulatory relationship between genes and their diagnostic value in GSE52004. Furthermore, in independent mouse RNA-seq datasets GSE98622, human RNA-seq GSE134386 and in vitro, the expression of hub genes and genes from the network were observed and correlation coefficient and ROC analysis were validated.

Results

A total of 21 DEMs and 187 DEGs were identified in renal IRI group compared to control group. The results of PPI analysis showed 15 hub genes. The TF-miRNA-mRNA regulatory network was constructed and several important pathways were identified and further verified, including Junb-miR-223-Ranbp3l, Cebpb-miR-223-Ranbp3l, Cebpb-miR-21-Ranbp3l and Cebpb-miR-181b-Bsnd. Four regulatory loops were identified, including Fosl2-miR-155, Fosl2-miR-146a, Cebpb-miR-155 and Mafk-miR-25. The hub genes and genes in the network showed good diagnostic value in mice and human.

Conclusions

In this study, we found 15 hub genes and several TF-miRNA-mRNA pathways, which are helpful for understanding the molecular and regulatory mechanisms in renal IRI. Junb-miR-223-Ranbp3l, Cebpb-miR-223-Ranbp3l, Cebpb-miR-21-Ranbp3l and Cebpb-miR-181b-Bsnd were the most important pathways, while Spp1, Fos, Timp1, Tnc, Fosl2 and Junb were the most important hub genes. Fosl2-miR-155, Fosl2-miR-146a, Cebpb-miR-155 and Mafk-miR-25 might be the negative feedback loops in renal IRI.

Inhibition of microRNA-297 alleviates THLE-2 cell injury induced by hypoxia/reoxygenation by inhibiting NLRP3 inflammasome activation via SIRT3

It has been acknowledged that microRNAs (miRNAs/miRs) assume a critical role in hypoxia/reoxygenation (H/R)-induced hepatocyte injury. Therefore, cell experiments were performed in this study to investigate the mechanism of miR-297 in H/R-induced hepatocyte injury with the involvement of Sirtuin 3 (SIRT3) and NLRP3. Initially, THLE-2 cells were utilized for H/R challenge. After miR-297 antagomir and NLRP3 adenovirus vector delivery, THLE-2 cell proliferation and apoptosis were measured by MTT, EdU and TUNEL assays, respectively. Enzyme-linked immunosorbent assay was conducted to evaluate the levels of apoptosis-related indicators (Bax and Bcl-2) and inflammation-related indicators (IL-6 and IL-10), western blot analysis to detect NLRP3 and Cleaved Caspase-1 expression. The binding relation between miR-297 and SIRT3 was examined using dual-luciferase assay. The results showed that miR-297 antagomir repressed the apoptosis and inflammation induced by H/R treatment in THLE-2 cells. Mechanistically, miR-297 antagomir diminished the extent of IκBα and NF-κB phosphorylation and NLRP3 activation in H/R-induced THLE-2 cells by targeting SIRT3. Furthermore, NLRP3 overexpression normalized the promoting effects of miR-297 antagomir on proliferation and its inhibitory effects on apoptosis and inflammation in H/R-induced THLE-2 cells. In summary, our results elucidated that miR-297 antagomir repressed H/R-induced THLE-2 cell injury via SIRT3 promotion and NLRP3 inactivation.

Extracellular vesicles derived from mesenchymal stem cells as a potential therapeutic agent in acute kidney injury (AKI) in felines: review and perspectives

Mesenchymal stem cells (MSCs), known from their key role in the regeneration process of tissues, and their abilities to release bioactive factors like extracellular vesicles (EVs) could be considered as a potential, modern tool in the treatment of AKI (acute kidney injury) in both human and veterinary patients. The complex pathophysiology of a renal function disorder (AKI) makes difficult to find a universal therapy, but the treatment strategy is based on MSCs and derived from them, EVs seem to solve this problem. Due to their small size, the ability of the cargo transport, the ease of crossing the barriers and the lack of the ability to proliferate and differentiate, EVs seem to have a significant impact on the development such therapy. Their additional impact associated with their ability to modulate immune response and inflammation process, their strong anti-fibrotic and anti-apoptotic effects and the relation with the releasing of the reactive oxygen species (ROS), that pivotal role in the AKI development is undoubtedly, limits the progress of AKI. Moreover, the availability of EVs from different sources encourages to extend research with using EVs from MSCs in AKI treatment in felines; in that, the possibilities of kidney injuries treatment are still limited to the classical therapies burdened with dangerous side effects. In this review, we underline the significance of the processes, in whose EVs are included during the AKI in order to show the potential benefits of EVs-MSCs-based therapies against AKI in felines.

Exosomes: Emerging Therapy Delivery Tools and Biomarkers for Kidney Diseases

Exosomes are nanometer-sized small EVs coated with bilayer structure, which are released by prokaryotic and eukaryotic cells. Exosomes are rich in a variety of biologically active substances, such as proteins, nucleotides, and lipids. Exosomes are widely present in various body fluids and cell culture supernatants, and it mediates the physiological and pathological processes of the body through the shuttle of these active ingredients to target cells. In recent years, studies have shown that exosomes from a variety of cell sources can play a beneficial role in acute and chronic kidney disease. In particular, exosomes derived from mesenchymal stem cells have significant curative effects on the prevention and treatment of kidney disease in preclinical trials. Besides, some encapsulated substances are demonstrated to exert beneficial effects on various diseases, so they have attracted much attention. In addition, exosomes have extensive sources, stable biological activity, and good biocompatibility and are easy to store and transport; these advantages endow exosomes with superior diagnostic value. With the rapid development of liquid biopsy technology related to exosomes, the application of exosomes in the rapid diagnosis of kidney disease has become more prominent. In this review, the latest development of exosomes, including the biosynthesis process, the isolation and identification methods of exosomes are systematically summarized. The utilization of exosomes in diagnosis and their positive effects in the repair of kidney dysfunction are discussed, along with the specific mechanisms. This review is expected to be helpful for relevant studies and to provide insight into future applications in clinical practice.

Mesenchymal stem cell-derived exosomal miR-143-3p suppresses myocardial ischemia-reperfusion injury by regulating autophagy

AIMS

Myocardial ischemia-reperfusion (I/R) injury is considered as a major obstacle of myocardial perfusion to save acute myocardial infarction, and causes a serious threat to human health. An extensive body of evidence has unveiled that mesenchymal stem cells (MSCs) as adult stem cells play a vital role in the field of damaged myocardial regeneration and repair. However, the biological role of MSCs derived-exosomes in the protection of myocardial I/R injury has not been elucidated.

MAIN METHODS

In this study, we isolated and characterized MSCs from the bone marrow of rats femur and tibia. H9c2 cells were administrated to established the cellular hypoxia-reoxygenation (H/R) model, and co-cultured with MSCs and MSCs-derived exosomes.

KEY FINDINGS

Functional experiments revealed that MSCs and MSCs-derived exosomes inhibited H/R-induced cell apoptosis and cell autophagy. Interestingly, rapamycin as an activator of autophagy reversed the positive effects of MSCs-derived exosomes, while 3-methyladenine (3-MA) as autophagy inhibitor further promoted the effects of MSCs-derived exosomes, indicating MSCs exerted its function on H/R injury by mediating autophagy. Subsequently, we found that CHK2-Beclin2 pathway participated in H/R-induced autophagy. Mechanistically, miR-143-3p directly targeted CHK2 and negatively regulated CHK2 expression. Moreover, repression of exosomal miR-143-3p promoted H/R-induced autophagy via CHK2-Beclin2 pathway. Consistent with the results of in vitro experiments, in vivo experiments confirmed that exosomal miR-143-3p effectively reduced cell apoptosis by regulating autophagy via CHK2-Beclin2 pathway.

SIGNIFICANCE

Collectively, our results indicated that MSCs-derived exosomal miR-143-3p might represent a promising option for the treatment of I/R injury.

Delayed Contralateral Nephrectomy Halted Post-Ischemic Renal Fibrosis Progression and Inhibited the Ischemia-Induced Fibromir Upregulation in Mice

(1) Background: Ischemia reperfusion (IR) is the leading cause of acute kidney injury (AKI) and results in predisposition to chronic kidney disease. We demonstrated that delayed contralateral nephrectomy (Nx) greatly improved the function of the IR-injured kidney and decelerated fibrosis progression. Our aim was to identify microRNAs (miRNA/miR) involved in this process. (2) Methods: NMRI mice were subjected to 30 min of renal IR and one week later to Nx/sham surgery. The experiments were conducted for 7-28 days after IR. On day 8, multiplex renal miRNA profiling was performed. Expression of nine miRNAs was determined with qPCR at all time points. Based on the target prediction, plexin-A2 and Cd2AP were measured by Western blot. (3) Results: On day 8 after IR, the expression of 20/1195 miRNAs doubled, and 9/13 selected miRNAs were upregulated at all time points. Nx reduced the expression of several ischemia-induced pro-fibrotic miRNAs (fibromirs), such as miR-142a-duplex, miR-146a-5p, miR-199a-duplex, miR-214-3p and miR-223-3p, in the injured kidneys at various time points. Plexin-A2 was upregulated by IR on day 10, while Cd2AP was unchanged. (4) Conclusion: Nx delayed fibrosis progression and decreased the expression of ischemia-induced fibromirs. The protein expression of plexin-A2 and Cd2AP is mainly regulated by factors other than miRNAs.

miR-223: An Effective Regulator of Immune Cell Differentiation and Inflammation

MicroRNAs (miRNAs) play a critical role in regulating various biological processes, such as cell differentiation and immune modulation by binding to their target genes. miR-223 is a miRNA with important functions and has been widely investigated in recent years. Under certain physiological conditions, miR-223 is regulated by different transcription factors, including sirtuin1 (Sirt1), PU.1 and Mef2c, and its biological functions are mediated through changes in its cellular or tissue expression. This review paper summarizes miR-223 biosynthesis and its regulatory role in the differentiation of granulocytes, dendritic cells (DCs) and lymphocytes, macrophage polarization, and endothelial and epithelial inflammation. In addition, it describes the molecular mechanisms of miR-223 in regulating lung inflammation, rheumatoid arthritis, enteritis, neuroinflammation and mastitis to provide insights into the existing molecular regulatory networks and therapies for inflammatory diseases in humans and animals.

Hydrogen sulfide attenuates renal I/R‑induced activation of the inflammatory response and apoptosis via regulating Nrf2‑mediated NLRP3 signaling pathway inhibition

Renal ischemia/reperfusion (I/R) injury can lead to acute renal failure, delayed graft function and graft rejection. Nucleotide-binding oligomerization domain NOD-like receptor containing pyrin domain 3 (NLRP3)-mediated inflammation participates in the development of renal injury. Nrf2 accelerates NLRP3 signaling pathway activation and further regulates the inflammatory response. In addition, hydrogen sulfide serves a protective role in renal injury; however, the detailed underlying mechanism remains poorly understood. The present study investigated whether Nrf2 and NLRP3 pathway participate in hydrogen sulfide-regulated renal I/R-induced activation of the inflammatory response and apoptosis. Wild-type and Nrf2-knockout (KO) mice underwent surgery to induce renal I/R via clamping of the bilateral renal pedicles. A total of 20 mg/kg MCC950 (an NLRP3 inhibitor) was injected intraperitoneally daily for 14 days prior to surgery. Renal tissue and blood were collected from the I/R model mice to analyze NLRP3 and Nrf2 mRNA expression levels, NLRP3, PYD and CARD domain containing, caspase-1, IL-1β, Nrf2 and heme oxygenase 1 protein expression levels, cell apoptosis, the secretion of tumor necrosis factor-α, IL-1β and IL-6 cytokines and renal histopathology and function. Renal I/R activated the NLRP3 and Nrf2 signaling pathways. Conversely, MCC950 treatment inhibited activation of the NLRP3 signaling pathway, and prevented I/R-induced renal injury, release of cytokines and apoptosis in renal I/R model mice. Sodium hydrosulfide (NaHS) not only alleviated upregulation of NLRP3 protein expression levels, but also relieved renal injury, release of cytokines and cell apoptosis induced by renal I/R in wild-type mice, but not in Nrf2-KO mice. NaHS alleviated NLRP3 inflammasome activation, renal injury, the inflammatory response and cell apoptosis via the Nrf2 signaling pathway in renal I/R model mice.

Platelet-rich plasma promotes MSCs exosomes paracrine to repair acute kidney injury via AKT/Rab27 pathway

Acute kidney injury (AKI) is defined by rapid deterioration of renal function, and is a common complication in hospitalized patients. Among the recent therapeutic options, mesenchymal stem cells (MSCs) are considered a promising therapeutic strategy for damaged tissue repair. Platelet rich plasma (PRP) regulates mesenchymal cells to repair tissue damage through the release of growth factors. In this study, we proposed a possible therapeutic use of MSCs stimulated by platelet-rich plasma (PRP-MSCs) in a glycerin-induced AKI murine model. In vivo and in vitro studies, showed that PRP-MSCs could significantly attenuate serum blood urea nitrogen and creatinine levels, and reverse the histopathological kidney damage. PRP-MSCs treatment reduced renal tubular cell apoptosis stimulated by glycerin. We confirmed that PRP promoted the proliferation and reinforced the stemness of MSCs by inducing YAP nucleus expression, and that PRP promoted MSCs exosomes in a paracrine manner to repair AKI through an activated AKT/Rab27 pathway. Our results revealed that the PRP stimulated MSCs paracrine pathway could effectively alleviate glycerin-induced AKI. Therefore, PRP pretreatment may be a new method to improve the therapeutic effect of MSCs.

Oxidative Stress, Inflammation, and Autophagy: Potential Targets of Mesenchymal Stem Cells-Based Therapies in Ischemic Stroke

Ischemic stroke is a leading cause of death worldwide; currently available treatment approaches for ischemic stroke are to restore blood flow, which reduce disability but are time limited. The interruption of blood flow in ischemic stroke contributes to intricate pathophysiological processes. Oxidative stress and inflammatory activity are two early events in the cascade of cerebral ischemic injury. These two factors are reciprocal causation and directly trigger the development of autophagy. Appropriate autophagy activity contributes to brain recovery by reducing oxidative stress and inflammatory activity, while autophagy dysfunction aggravates cerebral injury. Abundant evidence demonstrates the beneficial impact of mesenchymal stem cells (MSCs) and secretome on cerebral ischemic injury. MSCs reduce oxidative stress through suppressing reactive oxygen species (ROS) and reactive nitrogen species (RNS) generation and transferring healthy mitochondria to damaged cells. Meanwhile, MSCs exert anti-inflammation properties by the production of cytokines and extracellular vesicles, inhibiting proinflammatory cytokines and inflammatory cells activation, suppressing pyroptosis, and alleviating blood–brain barrier leakage. Additionally, MSCs regulation of autophagy imbalances gives rise to neuroprotection against cerebral ischemic injury. Altogether, MSCs have been a promising candidate for the treatment of ischemic stroke due to their pleiotropic effect.

Advances of miRNAs in kidney graft injury

Kidney transplantation is the preferred treatment for patients with end-stage renal disease. However, various types of kidney graft injury after transplantation are still key factors that affect the survival of the kidney graft. Therefore, exploring the underlying mechanisms involved is very important. Current diagnostic measures for kidney graft injury (including needle biopsy, blood creatinine, eGFR, etc.) have many limiting factors such as invasiveness, insufficient sensitivity and specificity, so they cannot provide timely and effective information to clinicians. As for kidney grafts that have occurred injury, the traditional treatment has a little efficacy and many side effects. Therefore, there is an urgent need for developing new biomarkers and targeted treatment for kidney graft injury. Recently, studies have found that miRNAs are involved in the regulation of the progression of kidney graft injury. At the same time, it has high stability in blood, urine, and other body fluids, so it is suggested to have the potential as a biomarker and therapeutic target for kidney graft injury. Here, we reviewed the miRNAs involved in the pathophysiology of kidney graft injury such as ischemia/reperfusion injury, acute rejection, drug-induced nephrotoxicity, chronic allograft dysfunction, BK virus infection, and the latest advances of miRNAs as biomarkers and therapeutic targets of kidney graft injury, then summarized the specific data of miRNAs expression level in kidney graft injury, which aims to provide a reference for subsequent basic research and clinical transformation.

Hepatocyte growth factor intervention to reduce myocardial injury and improve cardiac function on diabetic myocardial infarction rats

Acute myocardial infarction (AMI) is recognized to be a severe threat to people's health conditions and life quality. The accumulation of hepatocyte growth factor (HGF) in ischemic myocardium has been observed in both processes of experimental ischemia and reperfusion (I/R) and permanent coronary artery occlusion. The aim of the study was to investigate the effect of HGF on myocardial cell apoptosis, ventricular remodeling and cardiac function after myocardial infarction (MI) in diabetic rats, and to explore whether the effect is mediated by HGF/c-Met signaling pathway. MI significantly increases LVWI and RVWI and myocardial apoptotic index, and up-regulates the expression of HGF and c-Met at mRNA and protein levels in MI control group. The LVWI and RVWI, and myocardial apoptosis were reduced by treatment with HGF, which also increased the myocardial cell viability and the expression of HGF and c-Met. In summary, HGF significantly attenuates myocardial apoptosis and improves cardiac function after AMI in diabetic rats by further enhancing the activation of HGF/c-Met pathway.

miR-132-3p priming enhances the effects of mesenchymal stromal cell-derived exosomes on ameliorating brain ischemic injury

Backgrounds/aims

Mesenchymal stromal cell-derived exosomes (MSC-EXs) could exert protective effects on recipient cells by transferring the contained microRNAs (miRs), and miR-132-3p is one of angiogenic miRs. However, whether the combination of MSC-EXs and miR-132-3p has better effects in ischemic cerebrovascular disease remains unknown.

Methods

Mouse MSCs transfected with scrambler control or miR-132-3p mimics were used to generate MSC-EXs and miR-132-3p-overexpressed MSC-EXs (MSC-EXs^miR-132-3p). The effects of EXs on hypoxia/reoxygenation (H/R)-injured ECs in ROS generation, apoptosis, and barrier function were analyzed. The levels of RASA1, Ras, phosphorylations of PI3K, Akt and endothelial nitric oxide synthesis (eNOS), and tight junction proteins (Claudin-5 and ZO-1) were measured. Ras and PI3K inhibitors were used for pathway analysis. In transient middle cerebral artery occlusion (tMCAO) mouse model, the effects of MSC-EXs on the cerebral vascular ROS production and apoptosis, cerebral vascular density (cMVD), Evans blue extravasation, brain water content, neurological deficit score (NDS), and infarct volume were determined.

Results

MSC-EXs could deliver their carried miR-132-3p into target ECs, which functionally downregulated the target protein RASA1, while upregulated the expression of Ras and the downstream PI3K phosphorylation. Compared to MSC-EXs, MSC-EXs^miR-132-3p were more effective in decreasing ROS production, apoptosis, and tight junction disruption in H/R-injured ECs. These effects were associated with increased levels of phosphorylated Akt and eNOS, which could be abolished by PI3K inhibitor (LY294002) or Ras inhibitor (NSC 23766). In the tMCAO mouse model, the infusion of MSC-EXs^miR-132-3p was more effective than MSC-EXs in reducing cerebral vascular ROS production, BBB dysfunction, and brain injury.

Conclusion

Our results suggest that miR-132-3p promotes the beneficial effects of MSC-EXs on brain ischemic injury through protecting cerebral EC functions.

Renal ischemia/reperfusion injury: An insight on in vitro and in vivo models

Optimal tissue oxygenation is essential for its normal function. Suboptimal oxygenation or ischemia contributes to increased mortalities during various pathological conditions such as stroke, acute kidney injury (AKI), cardiac failure. Despite the rapid progression of renal tissue injury, the mechanism underlying renal ischemia/reperfusion injury (IRI) remains highly unclear. Experimental in vitro and in vivo models epitomizing the fundamental process is critical to the research of the pathogenesis of IRI and the development of plausible therapeutics. In this review, we describe the in vitro and in vivo models of IRI, ranges from proximal tubular cell lines to surgery-based animal models like clamping of both renal pedicles (bilateral IRI), clamping of one renal pedicle (unilateral IRI), clamping of one/or both renal arteries/or vein, or unilateral IRI with contralateral nephrectomy (uIRIx). Also, advanced technologies like three-dimensional kidney organoids, kidney-on-a-chip are explained. This review provides thoughtful information for establishing reliable and pertinent models for studying IRI-associated acute renal pathologies.

Mesenchymal Stem Cell-Derived Extracellular Vesicles: A Novel Cell-Free Therapy for Sepsis

Sepsis remains a serious and life-threatening disease with high morbidity and mortality. Due to the unique immunomodulatory, anti-inflammatory, anti-apoptotic, anti-microbial, anti-oxidative, and reparative properties, mesenchymal stem cells (MSCs) have been extensively used in preclinical and clinical trials for diverse diseases and have shown great therapeutic potential in sepsis. However, concerns remain regarding whether MSCs can become tumorigenic or have other side effects. Extracellular vesicles (EVs) are a heterogeneous group of membrane-enclosed particles released from almost any cell and perform an important role in intercellular communication. Recently, it has emerged that EVs derived from MSCs (MSC-EVs) appear to exert a therapeutic benefit similar to MSCs in protecting against sepsis-induced organ dysfunction by delivering a cargo that includes RNAs and proteins to target cells. More importantly, compared to their parent cells, MSC-EVs have a superior safety profile, can be safely stored without losing function, and possess other advantages. Hence, MSC-EVs may be used as a novel alternative to MSC-based therapy in sepsis. Here, we summarize the properties and applications of MSC-EVs in sepsis.

Immunomodulatory and Regenerative Effects of Mesenchymal Stem Cell-Derived Extracellular Vesicles in Renal Diseases

Mesenchymal stem cells (MSCs) have immunomodulatory and regenerative effects in many organs, including the kidney. Emerging evidence has shown that the trophic effects from MSCs are mainly mediated by the paracrine mechanism rather than the direct differentiation of MSCs into injured tissues. These secretomes from MSCs include cytokines, growth factors, chemokines and extracellular vesicles (EVs) containing microRNAs, mRNAs, and proteins. Many research studies have revealed that secretomes from MSCs have potential to ameliorate renal injury in renal disease models, including acute kidney injury and chronic kidney disease through a variety of mechanisms. These trophic mechanisms include immunomodulatory and regenerative effects. In addition, accumulating evidence has uncovered the specific factors and therapeutic mechanisms in MSC-derived EVs. In this article, we summarize the recent advances of immunomodulatory and regenerative effects of EVs from MSCs, especially focusing on the microRNAs.

miRNAs in stem cell-derived extracellular vesicles for acute kidney injury treatment: comprehensive review of preclinical studies

Stem cell therapy has been applied in many fields. Basic and clinical studies on stem cell therapy for acute kidney injury (AKI) have been conducted. Stem cells have been found to exert renal protection through a variety of mechanisms, such as regulating the immune system and secreting growth factors, cytokines, and extracellular vesicles (EVs). Among them, EVs are considered to be important mediators for stem cell protection because they contain various biological components, including microRNAs (miRNAs). miRNAs are a class of small RNAs that function in posttranscriptional gene regulation. A number of studies have confirmed that miRNAs in stem cell-derived EVs can protect from AKI. miRNAs can enter the injured renal tissue through EVs released from stem cells, thereby exerting anti-inflammatory, anti-apoptotic, anti-fibrotic, and pro-angiogenesis effects on AKI. However, the stem cell sources and AKI models used in these studies have differed. This article will summarize the miRNAs that play a role in kidney protection in stem cell EVs and clarifies the treatment characteristics and mechanisms of different miRNAs. This may provide a reference for clinical practice for acute and chronic kidney diseases.

Convergence of Cell Pharmacology and Drug Delivery

Cellular therapy is enabling new approaches to tackle significant unmet needs in areas such as regenerative medicine and immunotherapy. The pharmacology of cell therapeutics becomes of critical importance to assure that these new drugs work reproducibly and effectively. Cell pharmacology can benefit from adapting principles of classical molecular drug pharmacokinetics (PK) and pharmacodynamics (PD) to quantitatively understand rate-limiting constraints of cell fate after administration. Future innovations focused on improvements in drug delivery using a PK/PD perspective can aid in designing a cell therapeutic product to overcome any pharmacological barriers for a given disease application. Herein, we present a perspective on the development of an ex vivo mesenchymal stromal therapeutic using a PK/PD framework and also present examples of general cell engineering techniques that implicitly influence the PK/PD curve by genetically modifying cells to regulate their in vivo duration, biodistribution, and activity. Stem Cells Translational Medicine 2019;8:874&879.

Silencing of SNHG12 Enhanced the Effectiveness of MSCs in Alleviating Ischemia/Reperfusion Injuries via the PI3K/AKT/mTOR Signaling Pathway

Previous studies have reported that the long non-coding RNA SNHG12 (lncRNA SNHG12) plays a critical role in regulating the function of mesenchymal stem cells (MSCs); however, the effect of lncRNA SNHG12 on MSCs in injured brain tissue has rarely been reported. We studied the effect and mechanism of lncRNA SNHG12-modified mesenchymal stem cells (MSCs) in treating brain injuries caused by ischemia/reperfusion (I/R). I/R treated rat brain microvascular endothelial cells (BMECs) were co-cultured with MSCs or I/R pretreated MSCs. Next, BMEC proliferation was detected by using CCK-8 and EdU assays, and cell apoptosis was determined by using flow cytometry and the Hoechst staining method. Autophagy of BMECs was determined using immunofluorescence and expression of associated pathway proteins were measured by western blotting. Moreover, BMEC proliferation, apoptosis, and autophagy were also determined after the BMECs had been co-cultured with shSNHG12-MSCs. In addition, a rat model of middle cerebral artery occlusion (MCAO) was used to further confirm the findings obtained with cells. I/R treatment significantly decreased the proliferation of BMECs, but increased their levels of SNHG12 expression, apoptosis, and autophagy. However, co-culturing of BMECs with MSCs markedly alleviated the reduction in BMEC proliferation and the increases in BMEC apoptosis and autophagy, as well as the phosphorylation of PI3K, AKT, and mTOR proteins in BMECs that had been induced by I/R. Furthermore, shSNHG12 remarkably enhanced the effects of MSCs. In addition, an injection MSCs reduced the infarct areas and rates of cell apoptosis in MACO rats, and reduced the phosphorylation of PI3K, AKT, and mTOR proteins. Moreover, shSNHG12 enhanced the ameliorative effect of MSCs in treating brain injuries in the MACO rats. In conclusion, silencing of SNHG12 enhanced the effects of MSCs in reducing apoptosis and autophagy of BMECs by activating the PI3K/AKT/mTOR signaling pathway.

Exosomes from human-bone-marrow-derived mesenchymal stem cells protect against renal ischemia/reperfusion injury via transferring miR-199a-3p

Renal ischemia/reperfusion (I/R) injury is the main reason for acute kidney injury (AKI) and is closely related to high morbidity and mortality. In this study, we found that exosomes from human-bone-marrow-derived mesenchymal stem cells (hBMSC-Exos) play a protective role in hypoxia/reoxygenation (H/R) injury. hBMSC-Exos were enriched in miR-199a-3p, and hBMSC-Exo treatment increased the expression level of miR-199a-3p in renal cells. We further explored the function of miR-199a-3p on H/R injury. miR-199a-3p was knocked down in hBMSCs with a miR-199a-3p inhibitor. HK-2 cells cocultured with miR-199a-3p-knockdown hBMSCs were more susceptible to H/R injury and showed more apoptosis than those cocultured with hBMSCs or miR-199a-3p-overexpressing hBMSCs. Meanwhile, we found that HK-2 cells exposed to H/R treatment incubated with hBMSC-Exos decreased semaphorin 3A (Sema3A) and activated the protein kinase B (AKT) and extracellular-signal-regulated kinase (ERK) pathways. However, HK-2 cells cocultured with miR-199a-3p-knockdown hBMSCs restored Sema3A expression and blocked the activation of the AKT and ERK pathways. Moreover, knocking down Sema3A could reactivate the AKT and ERK pathways suppressed by a miR-199a-3p inhibitor. In vivo, we injected hBMSC-Exos into mice suffering from I/R injury; this treatment induced functional recovery and histologic protection and reduced cleaved caspase-3 and Sema3A expression levels, as shown by immunohistochemistry. On the whole, this study demonstrated an antiapoptotic effect of hBMSC-Exos, which protected against I/R injury, via delivering miR-199a-3p to renal cells, downregulating Sema3A expression and thereby activating the AKT and ERK pathways. These findings reveal a novel mechanism of AKI treated with hBMSC-Exos and provide a therapeutic method for kidney diseases.

Exosomes Derived from Mesenchymal Stem Cells Ameliorate Hypoxia/Reoxygenation-Injured ECs via Transferring MicroRNA-126

Mesenchymal stem cells (MSCs) show protective effects on ischemia/reperfusion- (I/R-) induced endothelial cell (EC) injury and vascular damage. Stem cell-released exosomes (EXs) could modulate target cell functions by delivering their cargos, and exert therapeutic effects as their mother cells. miR-126 is an important regulator of EC functions and angiogenesis. In this study, we determined whether EXs released from MSC-EXs provided beneficial effects on hypoxia/reoxygenation- (H/R-) injured ECs by transferring miR-126. MSCs were transfected with a miR-126 mimic or miR-126 short hairpin RNA to obtain miR-126-overexpressing MSC-EXs (MSC-EXs^miR-126) and miR-126 knockdown MSC-EXs (MSC-EXs^SimiR-126). For functional studies, H/R-injured ECs were coincubated with various MSC-EXs. The viability, migration, tube formation ability, and apoptosis of ECs were measured. miR-126 and proangiogenic/growth factor (VEGF, EGF, PDGF, and bFGF) expressions were detected by qRT-PCR. Akt, p-Akt, p-eNOS, and cleaved caspase-3 expressions were examined by western blot. The PI3K inhibitor (LY294002) was used in pathway analysis. We found that overexpression/knockdown of miR-126 increased/decreased the proliferation of MSCs, as well as miR-126 expression in their derived MSC-EXs. MSC-EXs^miR-126 were more effective in promoting proliferation, migration, and tube formation ability of H/R-injured ECs than MSC-EXs. These effects were associated with the increase in p-Akt/Akt and p-eNOS, which could be abolished by LY294002. Besides, MSC-EXs^miR-126 were more effective than MSC-EXs in reducing the apoptosis of ECs, coupled with the decrease in cleaved caspase-3. Moreover, compared to MSC-EXs, MSC-EXs^miR-126 significantly upregulated the level of VEGF, EGF, PDGF, and bFGF in H/R-injured ECs. Downregulation of miR-126 in MSC-EXs inhibited these effects of MSC-EXs. The results suggest that MSC-EXs could enhance the survival and angiogenic function of H/R-injured ECs via delivering miR-126 to ECs and subsequently activate the PI3K/Akt/eNOS pathway, decrease cleaved caspase-3 expression, and increase angiogenic and growth factors.

Potential therapeutic roles of stem cells in ischemia-reperfusion injury

Ischemia-reperfusion injury (I/RI), produced by an initial interruption of organ blood flow and its subsequent restoration, contributes significantly to the pathophysiologies of stroke, myocardial infarction, renal I/RI, intestinal I/RI and liver I/RI, which are major causes of disability (including transplant failure) and even mortality. While the restoration of blood flow is required to restore oxygen and nutrient requirements, reperfusion often triggers local and systemic inflammatory responses and subsequently elevate the ischemic insult where the duration of ischemia determines the magnitude of I/RI damage. I/RI increases vascular leakage, changes transcriptional and cell death programs, drives leukocyte entrapment and inflammation and oxidative stress in tissues. Therapeutic approaches which reduce complications associated with I/RI are desperately needed to address the clinical and economic burden created by I/RI. Stem cells (SC) represent ubiquitous and uncommitted cell populations with the ability to self-renew and differentiate into one or more developmental 'fates'. Like immune cells, stem cells can home to and penetrate I/R-injured tissues, where they can differentiate into target tissues and induce trophic paracrine signaling which suppress injury and maintain tissue functions perturbed by ischemia-reperfusion. This review article summarizes the present use and possible protective mechanisms underlying stem cell protection in diverse forms of ischemia-reperfusion.

Bone Marrow Derived Mesenchymal Stromal Cells Ameliorate Ischemia/Reperfusion Injury-Induced Acute Kidney Injury in Rats via Secreting Tumor Necrosis Factor-Inducible Gene 6 Protein

Aims

To investigate whether bone marrow derived mesenchymal stromal cells (BMSC) have ameliorated ischemia/reperfusion injury-induced acute kidney injury (IRI-AKI) via tumor necrosis factor-inducible gene 6 protein (TSG-6) and how TSG-6 exerted this effect.

Methods

We used lentiviral vectors of short hairpin RNA (shRNA) targeting TSG-6 gene to silence TSG-6 in BMSC. And TSG-6-silenced BMSC were administrated into IRI-AKI rats. Then we analyzed serum creatinine (Scr) and renal histology of IRI-AKI rats treated with BMSC after different pretreatments. Furthermore, we explored the effect of TSG-6 on renal tubular epithelial cells proliferation in vivo and in vitro assays.

Results

The Scr levels of IRI-AKI rats treated with BMSC (73.5±7.8 μmol/L) significantly decreased compared to those of IRI-AKI rats treated without BMSC (392.5±24.8 μmol/L, P<0.05) or with DMEM (314.0±19.8 μmol/L, P<0.05). Meanwhile, the renal tissue injury in IRI-AKI rats treated with BMSC improved markedly. However, the Scr levels of IRI-AKI rats treated with TSG-6-silenced BMSC (265.1±21.2 μmol/L) significantly increased compared to those with BMSC (74.0±8.5 μmol/L, P<0.05). The proportion of Ki67-positive cells was reduced in IRI-AKI rats treated with TSG-6-silenced BMSC compared to that in IRI-AKI rats treated with BMSC (29.7±0.8% versus 43.4±3.0%, P<0.05). In vitro, the cell proliferation rate of TSG-6-stimulated NRK-52E cells under hypoxia (89.2±3.9%) increased significantly compared to that of NRK-52E cells alone under hypoxia (82.4±0.8%, P<0.05). Similarly, the proportion of Ki67-positive cells was significantly elevated in TSG-6-stimulated NRK-52E cells under hypoxia. Furthermore, TSG-6 could inhibit infiltration of neutrophils in kidney tissue of IRI-AKI.

Conclusions

TSG-6 plays a key role in the treatment of IRI-AKI with BMSC, which may be due to its effect on promoting renal tubular epithelial cells proliferation by modulating inflammation.

Are cell-based therapies for kidney disease safe? A systematic review of preclinical evidence

The number of individuals affected by acute kidney injury (AKI) and chronic kidney disease (CKD) is constantly rising. In light of the limited availability of treatment options and their relative inefficacy, cell based therapeutic modalities have been studied. However, not many efforts are put into safety evaluation of such applications. The aim of this study was to review the existing published literature on adverse events reported in studies with genetically modified cells for treatment of kidney disease. A systematic review was conducted by searching PubMed and EMBASE for relevant articles published until June 2018. The search results were screened and relevant articles selected using pre-defined criteria, by two researchers independently. After initial screening of 6894 abstracts, a total number of 97 preclinical studies was finally included for full assessment. Of these, 61 (63%) presented an inappropriate study design for the evaluation of safety parameters. Only 4 studies (4%) had the optimal study design, while 32 (33%) showed sub-optimal study design with either direct or indirect evidence of adverse events. The high heterogeneity of studies included regarding cell type and number, genetic modification, administration route, and kidney disease model applied, combined with the consistent lack of appropriate control groups, makes a reliable safety evaluation of kidney cell-based therapies impossible. Only a limited number of relevant studies included looked into essential safety-related outcomes, such as inflammatory (48%), tumorigenic and teratogenic potential (12%), cell biodistribution (82%), microbiological safety with respect to microorganism contamination and latent viruses' reactivation (1%), as well as overall well-being and animal survival (19%). In conclusion, for benign cell-based therapies, well-designed pre-clinical studies, including all control groups required and good manufacturing processes securing safety, need to be done early in development. Preferably, this should be performed side by side with efficacy evaluation and according to the official guidelines of leading health organizations.

Chrysin protects against renal ischemia reperfusion induced tubular cell apoptosis and inflammation in mice

Renal ischemia reperfusion (IR) is a major cause of acute kidney injury with no effective treatment. Chrysin is an anti-inflammatory, anti-oxidant and anti-cancer agent. However, the effect of chrysin on renal IR injury remains unknown. In this study, sham operation, IR and IR+chrysin group mice were treated with or without renal IR injury. For renal IR, bilateral renal pedicles were clamped for 30 min and then released for 48 h of reperfusion. Blood and kidney samples were collected for analysis. Results demonstrated that chrysin pretreatment remarkably decreased the levels of serum creatinine and blood urea nitrogen and attenuated morphological abnormalities in renal IR injury. Consistently, tubular cell apoptosis and inflammation were more attenuated in the chrysin pretreatment group compared with the IR group. Chrysin pretreatment decreased the expression of Bax and cleaved caspase-3 and increased the expression of Bcl-2 in renal IR injury. Furthermore, chrysin administration decreased the mRNA and protein levels of tumor necrosis factor-α, interleukin (IL)-1β, and IL-6. Furthermore, the IκBα/nuclear factor-κB signaling pathway was more suppressed in the chrysin pretreatment group compared with the IR group. In conclusion, chrysin protects against tubular cell apoptosis and inflammation in renal IR injury.

A dual-mode nanoparticle based on natural biomaterials for photoacoustic and magnetic resonance imaging of bone mesenchymal stem cells in vivo

Stem cell imaging in vivo is critical to elucidate the homing, distribution, survival, and repair mechanisms and to evaluate the therapeutic effects of engrafted stem cells. Unfortunately, unimodal imaging of stem cells does not simultaneously satisfy all current requirements owing to their intrinsic limitations. Obviously, bimodal or multimodal imaging of stem cells is a promising strategy for circumventing this issue. This study aimed to design and synthesize a novel dual-modal polyethylene glycol-modified magnetic nanoparticle (Fe³⁺-PEG-MNP) based on natural biomaterials including melanin and Fe ions for photoacoustic (PA) and magnetic resonance (MR) imaging of stem cells in vivo. The Fe³⁺-PEG-MNPs were characterized and their PA/MR imaging capability and cytotoxicity were evaluated. Bone marrow mesenchymal stem cells (BM-MSCs) labeled with Fe³⁺-PEG-MNPs were subjected to PA and MR imaging in vitro and in vivo. Consequently, Fe³⁺-PEG-MNPs displayed many superior properties, including ultra-small particle size, higher stability, water solubility, easy labeling of cells, lower cytotoxicity, high biosafety, excellent capability of PA/MR imaging, high sensitivity and long-term monitoring in vitro and in vivo. In particular, PA and MR signals of labeled BM-MSCs were maintained for at least 35 and 28 d, respectively, in vivo. Therefore, Fe³⁺-PEG-MNPs are ideal dual-modal PA/MR nanoparticles for non-invasive and effective monitoring of engrafted stem cells in vivo.

Stem cell imaging in vivo is critical to elucidate the homing, distribution, survival, and repair mechanisms and to evaluate the therapeutic effects of engrafted stem cells.

Exosomes derived from preadipocytes improve osteogenic differentiation, potentially via reduced miR‑223 expression

Insufficient bone volume remains a key issue when using dental implants. Adipose tissue-derived stem cells (ADSCs) can accelerate bone healing when combined with dental implants. To improve the application of ADSCs for dental uses, the present study aimed to identify optimal implantation conditions. Mesenchymal stem cell-derived exosomes can induce naïve stem cells to differentiate through the osteogenic lineage. In the present study, exosomes derived from 3T3L1 preadipocytes (3T3L1-exo) were purified and characterized. The effects and potential mechanisms of 3T3L1-exo on 3T3L1 cell ossification were examined by reverse transcription-quantitative polymerase chain reaction, western blotting, electron microscopy, RNA sequencing and histological analysis. The current study confirmed that 3T3L1-exo enhanced 3T3L1 preadipocyte osteogenic differentiation, as revealed by upregulation of osteogenic differentiation-associated genes and increased Alizarin Red staining. Furthermore, the microRNA (miR) expression profiles of 3T3L1-exo and 3T3L1 preadipocytes were sequenced and compared. The results of a further analysis demonstrated that miR-223 expression was reduced in 3T3L1 preadipocytes stimulated by 3T3L1-exo compared with in unstimulated cells. This finding suggested that 3T3L1-exo promoted 3T3L1 bone formation by decreasing miR-223 through a competitive mechanism, another miRNA, or another factor. The mechanism by which miR-223 is decreased warrants further investigation. In conclusion, the application of 3T3L1-exo may be useful for investigating preadipocyte-induced bone regeneration.

Serum and Lipoprotein Particle miRNA Profile in Uremia Patients

microRNAs (miRNAs) are post-transcriptional regulators of messenger RNA (mRNA), and transported through the whole organism by—but not limited to—lipoprotein particles. Here, we address the miRNA profile in serum and lipoprotein particles of healthy individuals in comparison with patients with uremia. Moreover, we quantitatively determined the cellular lipoprotein-particle-uptake dependence on the density of lipoprotein particle receptors and present a method for enhancement of the transfer efficiency. We observed a significant increase of the cellular miRNA level using reconstituted high-density lipoprotein (HDL) particles artificially loaded with miRNA, whereas incubation with native HDL particles yielded no measurable effect. Thus, we conclude that no relevant effect of lipoprotein-particle-mediated miRNA-transfer exists under in vivo conditions though the miRNA profile of lipoprotein particles can be used as a diagnostic marker.

Resveratrol improves human umbilical cord-derived mesenchymal stem cells repair for cisplatin-induced acute kidney injury

Human umbilical cord-derived mesenchymal stem cells (hucMSCs) are a promising tool for damaged tissues repair, especially for the kidney. However, their efficacy requires improvement. In order to optimize the clinical utility of hucMSCs, we adopted a strategy of treating hucMSCs with 20 μmol/L of resveratrol (Res-hucMSCs), applying it in a cisplatin-induced acute kidney injury model. Interestingly, we found that Res-hucMSCs exhibited a more efficient repairing effect than did hucMSCs. Resveratrol-promoted hucMSCs secreted platelet-derived growth factor-DD (PDGF-DD) into renal tubular cells resulting in downstream phosphorylation of extracellular signal-regulated kinase (ERK), which inhibited renal tubular cells apoptosis. In contrast, PDGF-DD knockdown impaired the renal protection of Res-hucMSCs. In addition, angiogenesis induced by PDGF-DD in endothelial cells was also involved in the renal protection of Res-hucMSCs. The conditioned medium of Res-hucMSCs accelerated proliferation and migration of vascular endothelial cells in vitro and CD31 was in a high-level expression in Res-hucMSCs group in vivo. Nevertheless, the angiogenesis was abrogated when Res-hucMSCs were treated with PDGF-DD siRNA. In conclusion, our findings showed that resveratrol-modified hucMSCs activated ERK pathway in renal tubular cells and promoted angiogenesis in endothelial cells via paracrine PDGF-DD, which could be a novel strategy for enhancing the therapy efficacy of hucMSCs in cisplatin-induced kidney injury.

AMSC-derived exosomes alleviate lipopolysaccharide/d-galactosamine-induced acute liver failure by miR-17-mediated reduction of TXNIP/NLRP3 inflammasome activation in macrophages

Background

Mesenchymal stem cell (MSC)-derived exosome administration has been considered as a novel cell-free therapy for liver diseases through cell-cell communication. This study was aimed to determine the effects and mechanisms of AMSC-derived exosomes (AMSC-Exo) for acute liver failure (ALF) treatment.

Methods

AMSC-Exo were intravenously administrated into the mice immediately after lipopolysaccharide and D-galactosamine (LPS/GalN)-exposure and their effects were evaluated by liver histological and serum biochemical analysis. To elucidate its mechanisms in ALF therapy, the expression levels of miRNAs and inflammasome-related genes in macrophages were evaluated by qPCR and Western blot analysis, respectively. The exosomes from miR-17-knockdowned AMSCs (AMSC-Exo^miR-17-KD) were used for further determine the role of miR-17 in AMSC-Exo-based therapy.

Findings

AMSC-Exo administration significantly ameliorated ALF as determined by reduced serum alanine aminotransferase and aspartate aminotransferase levels and hepatic inflammasome activation. Further experiments revealed that AMSC-Exo were colocalized with hepatic macrophages and could reduce inflammatory factor secretion by suppressing inflammasome activation in macrophages. Moreover, miR-17, which can suppress NLRP3 inflammasome activation by targeting TXNIP, was abundant in AMSC-Exo cargo. While, the therapeutic effects of AMSC-Exo^miR-17-KD on ALF were significantly abolished as they could not effectively suppress TXNIP expression and consequent inflammasome activation in vitro and in vivo.

Interpretation: Exosome-shuttled miR-17 plays an essential role in AMSC-Exo therapy for ALF by targeting TXNIP and suppressing inflammasome activation in hepatic macrophages. AMSC-Exo-based therapy may present as a promising approach for TXNIP/NLRP3 inflammasome-related inflammatory liver diseases.

Fund

Key R&D projects of Zhejiang province (2018C03019) and National Natural Science Fund (81470851 and 81500616).

BMSCs-derived miR-223-containing exosomes contribute to liver protection in experimental autoimmune hepatitis

Autoimmune hepatitis is a chronic inflammatory disease in the liver with potential to the development of liver fibrosis. Recent evidences suggest that bone marrow derived mesenchymal stem cells (BMSCs) may exert its therapeutic activity through exosomes. Moreover, miR-223 is highly expressed in BMSCs and plays an important role in autoimmune diseases. Therefore, in this study, hepatoprotective role of BMSCs and miR-223 was investigated in both mice and hepatocytes. Liver antigen S100 was used to establish autoimmune hepatitis model in mice while LPS and ATP were used to establish cell injury model in hepatocyte. Before the experiments, BMSCs were infected with pre-miR-223 and transfected with miR-223 inhibitor respectively. Exosomes from bone marrow stem cells were isolated by ultracentrifugation. Liver injury was evaluated by serum levels of ALT and AST as well as liver histology. Inflammation and cell death were examined by inflammatory cytokines and lactase dehydrogenase respectively. Both BMSCs-exo and BMSCs-exo^miR-223(+) significantly reversed either S100 or LPS/ATP induced injury in mice and hepatocytes. Meanwhile, the expressions of cytokines, NLRP3 and caspase-1 were also downregulated by BMSCs-exo and BMSCs-exo^miR-223(+) at both protein and mRNA levels in mice and hepatocytes. Moreover, BMSCs-exo^miR-223(-) reverses the effects of BMSCs-exo and BMSCs-exo^miR-223(+) in mouse AIH and in hepatocytes. In conclusion, bone marrow stem cell derived exosomes can protect liver injury in an experimental model of autoimmune hepatitis and the mechanism could be related to exosomal miR-223 regulation of NLRP3 and caspase-1.

Role of hypoxia‑mediated cellular prion protein functional change in stem cells and potential application in angiogenesis (Review)

Cellular prion protein (PrP^C) can replace other pivotal molecules due to its interaction with several partners in performing a variety of important biological functions that may differ between embryonic and mature stem cells. Recent studies have revealed major advances in elucidating the putative role of PrP^C in the regulation of stem cells and its application in stem cell therapy. What is special about PrP^C is that its expression may be regulated by hypoxia-inducible factor (HIF)-1α, which is the transcriptional factor of cellular response to hypoxia. Hypoxic conditions have been known to drive cellular responses that can enhance cell survival, differentiation and angiogenesis through adaptive processes. Our group recently reported hypoxia-enhanced vascular repair of endothelial colony-forming cells on ischemic injury. Hypoxia-induced AKT/signal transducer and activator of transcription 3 phosphorylation eventually increases neovasculogenesis. In stem cell biology, hypoxia promotes the expression of growth factors. According to other studies, aspects of tissue regeneration and cell function are influenced by hypoxia, which serves an essential role in stem cell HIF-1α signaling. All these data suggest the possibility that hypoxia-mediated PrP^C serves an important role in angiogenesis. Therefore, the present review summarizes the characteristics of PrP^C, which is produced by HIF-1α in hypoxia, as it relates to angiogenesis.