PEP-1-CAT-transduced mesenchymal stem cells acquire an enhanced viability and promote ischemia-induced angiogenesis

Enhanced Transdermal Absorption of Hyaluronic Acid via Fusion with Pep-1 and a Hyaluronic Acid Binding Peptide

It is always big challenges for hyaluronic acid (HA) in transmembrane absorbing and efficient delivering to the skin. Pep-1, as one of the cell-penetrating peptides, has been documented to permeate various substances across cellular membranes without covalent binding. Here, a novel hyaluronic acid binding peptide (named HaBP) is designed, and then combined with Pep-1 to enhance the cell-penetrating efficiency of HA. The results of ELISA and immunofluorescence assay show that HaBP could bind with HA very well, and a combination of Pep-1 and HaBP could efficiently improve the transmembrane ability of HA. Furthermore, HA gradually enters the dermis from the surface of the skin in mice when it is administrated with both HaBP and Pep-1, while there are no obvious allergies or other adverse reactions during this process. This study finds a new method to promote the efficient transmembrane and transdermal absorption of HA, and throws some light on further research on the development of hyaluronic acid and its related cosmetics or drugs.

Enhancement of the efficacy of mesenchymal stem cells in the treatment of ischemic diseases

Ischemic diseases refer to a wide range of diseases caused by reduced blood flow and a subsequently deficient oxygen and nutrient supply. The pathogenesis of ischemia is multifaceted and primarily involves inflammation, oxidative stress and an apoptotic response. Over the last decade, mesenchymal stem cells (MSCs) have been widely studied as potential cell therapy agents for ischemic diseases due to their multiple favourable functions. However, the low homing and survival rates of transplanted cells have been concerns limiting for their clinical application. Recently, increasing studies have attempted to enhance the efficacy of MSCs by various strategies including genetic modification, pretreatment, combined application and biomaterial application. The purpose of this review is to summarize these creative strategies and the progress in basic and preclinical studies.

miR-10a rejuvenates aged human mesenchymal stem cells and improves heart function after myocardial infarction through KLF4

Background

Aging is one of the key factors that regulate the function of human bone marrow mesenchymal stem cells (hBM-MSCs) and related changes in microRNA (miRNA) expression. However, data reported on aging-related miRNA changes in hBM-MSCs are limited.

Methods

We demonstrated previously that miR-10a is significantly decreased in aged hBM-MSCs and restoration of the miR-10a level attenuated cell senescence and increased the differentiation capacity of aged hBM-MSCs by repressing Krüpple-like factor 4 (KLF4). In the present study, miR-10a was overexpressed or KLF4 was downregulated in old hBM-MSCs by lentiviral transduction. The hypoxia-induced apoptosis, cell survival, and cell paracrine function of aged hBM-MSCs were investigated in vitro. In vivo, miR-10a-overexpressed or KLF4-downregulated old hBM-MSCs were implanted into infarcted mouse hearts after myocardial infarction (MI). The mouse cardiac function of cardiac angiogenesis was measured and cell survival of aged hBM-MSCs was investigated.

Results

Through lentivirus-mediated upregulation of miR-10a and downregulation of KLF4 in aged hBM-MSCs in vitro, we revealed that miR-10a decreased hypoxia-induced cell apoptosis and increased cell survival of aged hBM-MSCs by repressing the KLF4–BAX/BCL2 pathway. In vivo, transplantation of miR-10a-overexpressed aged hBM-MSCs promoted implanted stem cell survival and improved cardiac function after MI. Mechanistic studies revealed that overexpression of miR-10a in aged hBM-MSCs activated Akt and stimulated the expression of angiogenic factors, thus increasing angiogenesis in ischemic mouse hearts.

Conclusions

miR-10a rejuvenated aged hBM-MSCs which improved angiogenesis and cardiac function in injured mouse hearts.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0895-0) contains supplementary material, which is available to authorized users.

Thioredoxin-1 Protects Bone Marrow-Derived Mesenchymal Stromal Cells from Hyperoxia-Induced Injury In Vitro

Background

The poor survival rate of mesenchymal stromal cells (MSC) transplanted into recipient lungs greatly limits their therapeutic efficacy for diseases like bronchopulmonary dysplasia (BPD). The aim of this study is to evaluate the effect of thioredoxin-1 (Trx-1) overexpression on improving the potential for bone marrow-derived mesenchymal stromal cells (BMSCs) to confer resistance against hyperoxia-induced cell injury.

Methods

80% O₂ was used to imitate the microenvironment surrounding-transplanted cells in the hyperoxia-induced lung injury in vitro. BMSC proliferation and apoptotic rates and the levels of reactive oxygen species (ROS) were measured. The effects of Trx-1 overexpression on the level of antioxidants and growth factors were investigated. We also investigated the activation of apoptosis-regulating kinase-1 (ASK1) and p38 mitogen-activated protein kinases (MAPK).

Result

Trx-1 overexpression significantly reduced hyperoxia-induced BMSC apoptosis and increased cell proliferation. We demonstrated that Trx-1 overexpression upregulated the levels of superoxide dismutase and glutathione peroxidase as well as downregulated the production of ROS. Furthermore, we illustrated that Trx-1 protected BMSCs against hyperoxic injury via decreasing the ASK1/P38 MAPK activation rate.

Conclusion

These results demonstrate that Trx-1 overexpression improved the ability of BMSCs to counteract hyperoxia-induced injury, thus increasing their potential to treat hyperoxia-induced lung diseases such as BPD.

Mesenchymal Stem Cell Therapy Protects Lungs from Radiation-Induced Endothelial Cell Loss by Restoring Superoxide Dismutase 1 Expression

AIMS

Radiation-induced normal tissue toxicity is closely linked to endothelial cell (EC) damage and dysfunction (acute effects). However, the underlying mechanisms of radiation-induced adverse late effects with respect to the vascular compartment remain elusive, and no causative radioprotective treatment is available to date.

RESULTS

The importance of injury to EC for radiation-induced late toxicity in lungs after whole thorax irradiation (WTI) was investigated using a mouse model of radiation-induced pneumopathy. We show that WTI induces EC loss as long-term complication, which is accompanied by the development of fibrosis. Adoptive transfer of mesenchymal stem cells (MSCs) either derived from bone marrow or aorta (vascular wall-resident MSCs) in the early phase after irradiation limited the radiation-induced EC loss and fibrosis progression. Furthermore, MSC-derived culture supernatants rescued the radiation-induced reduction in viability and long-term survival of cultured lung EC. We further identified the antioxidant enzyme superoxide dismutase 1 (SOD1) as a MSC-secreted factor. Importantly, MSC treatment restored the radiation-induced reduction of SOD1 levels after WTI. A similar protective effect was achieved by using the SOD-mimetic EUK134, suggesting that MSC-derived SOD1 is involved in the protective action of MSC, presumably through paracrine signaling.

INNOVATION

In this study, we explored the therapeutic potential of MSC therapy to prevent radiation-induced EC loss (late effect) and identified the protective mechanisms of MSC action.

CONCLUSIONS

Adoptive transfer of MSCs early after irradiation counteracts radiation-induced vascular damage and EC loss as late adverse effects. The high activity of vascular wall-derived MSCs for radioprotection may be due to their tissue-specific action. Antioxid. Redox Signal. 26, 563-582.

Apelin promotes mesenchymal stem cells survival and vascularization under hypoxic-ischemic condition in vitro involving the upregulation of vascular endothelial growth factor

BACKGROUND

Mesenchymal stem cells (MSCs) transplantation has been regarded as an optimal therapeutic approach for cardiovascular disease. However, the inferior survival and low vascularization potential of these cells in the local infarct site reduce the therapeutic efficacy. In this study, we investigated the influence of apelin on MSCs survival and vascularization under hypoxic-ischemic condition in vitro and explored the relevant mechanism.

METHODS

MSCs were obtained from C57BL/6 mice and cultured in vitro. Cells of the third passage were divided into MSCs and MSCs+apelin groups. In the MSCs+apelin group, MSCs were stimulated with apelin-13 (5μM). The two groups experienced exposure to hypoxia (1% O₂) and serum deprivation for 24h, using normoxia (20% O₂) as a negative control during the process. Human umbilical vein endothelial cells (HUVECs) were used and incubated with conditioned media from both groups to promote vascularization for another 6h. Vascular densities were assessed and relevant biomarkers were detected thereafter.

RESULTS

Compared with MSCs group, MSCs+apelin group presented more rapid growth. The proliferation rate was much higher. Cells apoptosis percentage was significantly declined both under normoxic and hypoxic conditions. Media produced from MSCs+apelin group triggered HUVECs to form a larger number of vascular branches on matrigel. The expression and secretion of vascular endothelial growth factor (VEGF) were significantly increased.

CONCLUSION

Apelin could effectively promote MSCs survival and vascularization under hypoxic-ischemic condition in vitro, and this procedure was associated with the upregulation of VEGF. This study provides a new perspective for exploring novel approaches to enhance MSCs survival and vascularization potential.

Dual effects of VEGF-B on activating cardiomyocytes and cardiac stem cells to protect the heart against short- and long-term ischemia-reperfusion injury

Aims

To investigate whether vascular endothelial growth factor B (VEGF-B) improves myocardial survival and cardiac stem cell (CSC) function in the ischemia–reperfusion (I/R) heart and promotes CSC mobilization and angiogenesis.

Methods and results

One hour after myocardial ischemia and infarction, rats were treated with recombinant human VEGF-B protein following 24 h or 7 days of myocardial reperfusion. Twenty-four hours after myocardial I/R, VEGF-B increased pAkt and Bcl-2 levels, reduced p-p38MAPK, LC3-II/I, beclin-1, CK, CK-MB and cTnt levels, triggered cardiomyocyte protection against I/R-induced autophagy and apoptosis, and contributed to the decrease of infarction size and the improvement of heart function during I/R. Simultaneously, an in vitro hypoxia-reoxygenation (H/R)-induced H9c2 cardiomyocyte injury model was used to mimic I/R injury model in vivo; in this model, VEGF-B decreased LDH release, blocked H/R-induced apoptosis by inhibiting cell autophagy, and these special effects could be abolished by the autophagy inducer, rapamycin. Mechanistically, VEGF-B markedly activated the Akt signaling pathway while slightly inhibiting p38MAPK, leading to the blockade of cell autophagy and thus protecting cardiomyocyte from H/R-induced activation of the intrinsic apoptotic pathway. Seven days after I/R, VEGF-B induced the expression of SDF-1α and HGF, resulting in the massive mobilization and homing of c-Kit positive cells, triggering further angiogenesis and vasculogenesis in the infracted heart and contributing to the improvement of I/R heart function.

Conclusion

VEGF-B could contribute to a favorable short- and long-term prognosis for I/R via the dual manipulation of cardiomyocytes and CSCs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0847-3) contains supplementary material, which is available to authorized users.

Intravenous Injections of Human Mesenchymal Stromal Cells Modulated the Redox State in a Rat Model of Radiation Myelopathy

The main aim of the present study was to assess the antioxidative effects of human umbilical cord-derived mesenchymal stromal cells (UC-MSCs) in a rat model of radiation myelopathy. UC-MSCs were isolated from Wharton's jelly (WJ) of umbilical cords. An irradiated cervical spinal cord rat model (C2-T2 segment) was generated using a ⁶⁰Co irradiator to deliver 30 Gy of radiation. UC-MSCs were injected through the tail vein at 90 days, 97 days, 104 days, and 111 days after-irradiation. Histological damage was examined by cresyl violet/Nissl staining. The activities of two antioxidant enzymes catalase (CAT) and glutathione peroxidase (GPX) in the spinal cord were measured by the biomedical assay. In addition, the levels of vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang-2) in the spinal cord were determined by ELISA methods. Multiple injections of UC-MSCs through the tail vein ameliorated neuronal damage in the spinal cord, increased the activities of the antioxidant enzymes CAT and GPX, and increased the levels of VEGF and Ang-2 in the spinal cord. Our results suggest that multiple injections of UC-MSCs via the tail vein in the rat model of radiation myelopathy could significantly improve the antioxidative microenvironment in vivo.

Preconditioning with PEP-1-SOD1 fusion protein attenuates ischemia/reperfusion-induced ventricular arrhythmia in isolated rat hearts

PEP 1-Cu/Zn superoxide dismutase (PEP-1-SOD1) fusion protein preconditioning has been reported to protect the myocardium from ischemia/reperfusion (I/R)-induced injury by decreasing the infarct size, reducing levels of cardiomyocyte apoptosis and reducing the release of myocardial-specific biomarkers. The aim of the present study was to examine the effects of PEP-1-SOD1 pretreatment on I/R-induced ventricular arrhythmias in Langendorff-perfused rat hearts. The isolated rat hearts were pretreated with PEP-1-SOD1 prior to I/R, and the I/R-induced hemodynamic parameters, infarct size and ventricular arrhythmias were then assessed. Compared with the unprotected hearts, PEP-1-SOD1 preconditioning significantly improved the hemodynamic parameters, decreased the cardiac lactate dehydrogenase and creatine kinase-MB (CK-MB) levels, reduced the infarct size and attenuated the ventricular arrhythmia. Further investigation showed that PEP-1-SOD1 preconditioning reduced both the incidence and duration of ventricular tachycardia/ventricular fibrillation. In addition, the intracellular reactive oxygen species (ROS) levels were decreased. The results of the present study suggest that PEP-1-SOD1 preconditioning can protect the heart against I/R injury and attenuate I/R-induced arrhythmia by downregulating the generation of ROS.

Exendin-4 protects adipose-derived mesenchymal stem cells from apoptosis induced by hydrogen peroxide through the PI3K/Akt-Sfrp2 pathways

Adipose-derived mesenchymal stem cells (ADMSCs)-based therapy is a promising modality for the treatment of myocardial infarction in the future. However, the majority of transplanted cells are readily lost after transplantation because of hypoxia and oxidative stress. An efficient means to enhance the ability of ADMSCs to survive under pathologic conditions is required. In our study, we explored the effects of exendin-4 (Ex-4) on ADMSCs apoptosis in vitro induced by hydrogen peroxide, focusing in particular on mitochondrial apoptotic pathways and PI3K/Akt-secreted frizzled-related protein 2 (Sfrp2) survival signaling. We demonstrated that ADMSCs subjected to H2O2 for 12h exhibited impaired mitochondrial function and higher apoptotic rate. However, Ex-4 (1-20 nM) preconditioning for 12h could protect ADMSCs against H2O2-mediated apoptosis in a dose-dependent manner. Furthermore, Ex-4 pretreatment upregulated the levels of superoxide dismutase and glutathione as well as downregulating the production of reactive oxygen species and malondialdehyde. Western blots revealed that increased antiapoptotic proteins Bcl-2 and c-IAP1/2 as well as decreased proapoptotic proteins Bax and cytochrome c appeared in ADMSCs with Ex-4 incubation, which inhibited the caspase-9-involved mitochondrial apoptosis pathways with evidence showing inactivation of caspase-9/3 and preservation of mitochondrial membrane potential. Furthermore, we illustrated that Ex-4 enhanced Akt phosphorylation, which increased the expression of Sfrp2. Notably, blockade of the PI3K/Akt pathway or knockdown of Sfrp2 with siRNA obviously abolished the protective effects of Ex-4 on mitochondrial function and ADMSCs apoptosis under H2O2. In summary, this study confirmed that H2O2 induced ADMSCs apoptosis through mitochondria-dependent cell death pathways, and Ex-4 preconditioning may reduce such apoptosis of ADMSCs through the PI3K/Akt-Sfrp2 pathways.

Decreased SIRT3 in aged human mesenchymal stromal/stem cells increases cellular susceptibility to oxidative stress

Sirtuin3 (SIRT3) is an important member of the sirtuin family of protein deacetylases that is localized to mitochondria and linked to lifespan extension in organisms ranging from yeast to humans. As aged cells have less regenerative capacity and are more susceptible to oxidative stress, we investigated the effect of ageing on SIRT3 levels and its correlation with antioxidant enzyme activities. Here, we show that severe oxidative stress reduces SIRT3 levels in young human mesenchymal stromal/stem cells (hMSCs). Overexpression of SIRT3 improved hMSCs resistance to the detrimental effects of oxidative stress. By activating manganese superoxide dismutase (MnSOD) and catalase (CAT), SIRT3 protects hMSCs from apoptosis under stress. SIRT3 expression, levels of MnSOD and CAT, as well as cell survival showed little difference in old versus young hMSCs under normal growth conditions, whereas older cells had a significantly reduced capacity to withstand oxidative stress compared to their younger counterparts. Expression of the short 28 kD SIRT3 isoform was higher, while the long 44 kD isoform expression was lower in young myocardial tissues compared with older ones. These results suggest that the active short isoform of SIRT3 protects hMSCs from oxidative injury by increasing the expression and activity of antioxidant enzymes. The expression of this short isoform decreases in cardiac tissue during ageing, leading to a reduced capacity for the heart to withstand oxidative stress.

The green tea extract epigallocatechin-3-gallate inhibits irradiation-induced pulmonary fibrosis in adult rats

The present study evaluated the effect of epigallocatechin-3-gallate (EGCG), the most abundant catechin in green tea, on irradiation-induced pulmonary fibrosis and elucidated its mechanism of action. A rat model of irradiation-induced pulmonary fibrosis was generated using a ⁶⁰Co irradiator and a dose of 22 Gy. Rats were intraperitoneally injected with EGCG (25 mg/kg) or dexamethasone (DEX; 5 mg/kg) daily for 30 days. Mortality rates and lung index values were calculated. The severity of fibrosis was evaluated by assaying the hydroxyproline (Hyp) contents of pulmonary and lung tissue sections post-irradiation. Alveolitis and fibrosis scores were obtained from semi-quantitative analyses of hematoxylin and eosin (H&E) and Masson’s trichrome lung section staining, respectively. The serum levels of transforming growth factor β1 (TGF-β1), interleukin (IL)-6, IL-10, and tumor necrosis factor-α (TNF-α) were also measured. Surfactant protein-B (SPB) and α-SMA expression patterns were evaluated using immunohistochemistry, and the protein levels of nuclear transcription factor NF-E2-related factor 2 (Nrf-2) and its associated antioxidant enzymes heme oxygenase-1 enzyme (HO-1) and NAD(P)H:quinone oxidoreductase-1 (NQO-1) were examined via western blot analysis. Treatment with EGCG, but not DEX, reduced mortality rates and lung index scores, improved histological changes in the lung, reduced collagen depositions, reduced MDA content, enhanced SOD activity, inhibited (myo)fibroblast proliferation, protected alveolar epithelial type II (AE2) cells, and regulated serum levels of TGF-β1, IL-6, IL-10, and TNF-α. Treatment with EGCG, but not DEX, activated Nrf-2 and its downstream antioxidant enzymes HO-1 and NQO-1. Taken together, these results showed that EGCG treatment significantly inhibits irradiation-induced pulmonary fibrosis. Furthermore, the results suggested promising clinical EGCG therapies to treat this disorder.

Transduced PEP-1-heme oxygenase-1 fusion protein protects against intestinal ischemia/reperfusion injury

BACKGROUND

Heme oxygenase-1 (HO-1) has been shown to have antioxidant and anti-apoptotic properties. The present study transduced HO-1 protein into intestinal tissues using PEP-1, a cell-penetrating peptide, and investigated its potentiality in prevention against intestinal ischemia/reperfusion (I/R) injury.

MATERIALS AND METHODS

PEP-1-HO-1 fusion protein was administered intravenously to explore the time and dose characteristics through measuring serum HO-1 levels. Twenty-four male Sprague-Dawley rats were randomly divided into three groups: sham, intestinal I/R (II/R), II/R + PEP-1-HO-1 fusion protein (HO). The model was established by occluding the superior mesenteric artery for 45 min followed by 120 min reperfusion. In HO group, PEP-1-HO-1 was administered intravenously 30 min before ischemia, whereas animals in sham and II/R groups received the equal volume of physiological saline. After the experiment, the intestines were harvested for determination of histologic injury, wet/dry ratio, enzyme activity, apoptosis, and His-probe protein (one part of PEP-1-HO-1).

RESULTS

Levels of serum HO-1 were dose- and time-dependent manner after intravenous injection of PEP-1-HO-1. I/R caused deterioration of histologic characteristics and increases in histologic injury scoring, wet/dry ratio, myeloperoxidase activity, malondialdehyde, and intestinal apoptosis. These changes were also accompanied by a decrease in superoxide dismutase activity (P < 0.05). PEP-1-HO-1 treatment significantly reversed these changes (P < 0.05). Furthermore, His-probe protein expression was only detected in PEP-1-HO-1-treated animals.

CONCLUSION

Treatment of PEP-1-HO-1 attenuates intestinal I/R injury, which might be attributable to its antioxidant and anti-apoptotic roles of HO-1.