Retinoic acid released from self-assembling peptide activates cardiomyocyte proliferation and enhances repair of infarcted myocardium.

The limited cardiomyocyte proliferation is insufficient for repair of the myocardium. Therefore, activating cardiomyocyte proliferation might be a reasonable option for myocardial regeneration. Here, we investigated effect of retinoic acid (RA) on inducing adult cardiomyocyte proliferation and assessed efficacy of self-assembling peptide (SAP)-released RA in activating regeneration of the infarcted myocardium. Effect of RA on inducing cardiomyocyte proliferation was examined with the isolated cardiomyocytes. Expression of the cell cycle-associated genes and paracrine factors in the infarcted myocardium was examined at one week after treatment with SAP-carried RA. Cardiomyocyte proliferation, myocardial regeneration and improvement of cardiac function were assessed at four weeks after treatment. In the adult rat myocardium, expression of RA synthetase gene Raldh2 and RA concentration were decreased significantly. After treatment with RA, the proliferated cardiomyocytes were increased. The formulated SAP could sustainedly release RA. After treatment with SAP-carried RA, expression of the pro-proliferative genes in cell cycle and paracrine factors in the infarcted myocardium were up-regulated. Myocardial regeneration was enhanced, and cardiac function was improved significantly. These results demonstrate that RA can induce adult cardiomyocytes to proliferate effectively. The sustained release of RA with SAP is a promise strategy to enhance repair of the infarcted myocardium.

Lymphangiogenesis, a potential treatment target for myocardial injury.

The lymphatic vascular system is crucial for the regulation of tissue fluid homeostasis, lipid metabolism, and immune function. Cardiac injury quickly leads to myocardial edema, cardiac lymphatic dysfunction, which ultimately results in myocardial fluid imbalance and cardiac dysfunction. Therefore, lymphangiogenesis-targeted therapy may improve the recovery of myocardial function post cardiac ischemia as observed in myocardial infarction (MI). Indeed, a promising strategy for the clinical treatment of MI relies on vascular endothelial growth factor-C (VEGF-C)-targeted therapy, which promotes lymphangiogenesis. However, much effort is needed to identify the mechanisms of lymphatic transport in response to heart disease. This article reviews regulatory factors of lymphangiogenesis, and discusses the effects of lymphangiogenesis on cardiac function after cardiac injury and its regulatory mechanisms. The involvement of stem cells on lymphangiogenesis was also discussed as stem cells could differentiate into lymphatic endothelial cells (LECs) and stimulate phenotype of LECs.

Notoginsenoside R1-loaded mesoporous silica nanoparticles targeting the site of injury through inflammatory cells improves heart repair after myocardial infarction.

Notoginsenoside R1 (NGR1) is the main monomeric component extracted from the dried roots and rhizomes of Panax notoginseng, and exerts pharmacological action against myocardial infarction (MI). Owing to the differences in compound distribution, absorption, and metabolism in vivo, exploring a more effective drug delivery system with a high therapeutic targeting effect is crucial. In the early stages of MI, CD11b-expressing monocytes and neutrophils accumulate at infarct sites. Thus, we designed a mesoporous silica nanoparticle-conjugated CD11b antibody with loaded NGR1 (MSN-NGR1-CD11b antibody), which allowed NGR1 precise targeted delivery to the heart in a noninvasively manner. By increasing targeting to the injured myocardium, intravenous injection of MSN-NGR1-CD11b antibody nanoparticle in MI mice improved cardiac function and angiogenesis, reduced cell apoptosis, and regulate macrophage phenotype and inflammatory factors and chemokines. In order to further explore the mechanism of NGR1 protecting myocardium, cell oxidative stress model and oxygen-glucose deprivation (OGD) model were established. NGR1 protected H9C2 cells and primary cardiomyocytes against oxidative injury induced by H2O2 and OGD treatment. Further network pharmacology and molecular docking analyses suggested that the AKT, MAPK and Hippo signaling pathways were involved in the regulation of NGR1 in myocardial protection. Indeed, NGR1 could elevate the levels of p-Akt and p-ERK, and promote the nuclear translocation of YAP. Furthermore, LY294002 (AKT inhibitor), U0126 (ERK1/2 inhibitor) and Verteporfin (YAP inhibitor) administration in H9C2 cells indicated the involvement of AKT, MAPK and Hippo signaling pathways in NGR1 effects. Meanwhile, MSN-NGR1-CD11b antibody nanoparticles enhanced the activation of AKT and MAPK signaling pathways and the nuclear translocation of YAP at the infarcted site. Our research demonstrated that MSN-NGR1-CD11b antibody nanoparticle injection after MI enhanced the targeting of NGR1 to the infarcted myocardium and improved cardiac function. More importantly, our pioneering research provides a new strategy for targeting drug delivery systems to the ischemic niche.

Thymosin ß4 released from functionalized self-assembling peptide activates epicardium and enhances repair of infarcted myocardium.

The epicardium plays an important role in cardiomyogenesis during development, while it becomes quiescent in adult heart during homeostasis. This study investigates the efficiency of thymosin ß4 (Tß4) release with RPRHQGVM conjugated to the C-terminus of RADA16-I (RADA-RPR), the functionalized self-assembling peptide (SAP), to activate the epicardium and repairing the infarcted myocardium. Methods: The functionalized SAP was constituted with self-assembling motif, Tß4-binding site, and cell adhesive ligand. Myocardial infarction (MI) models of the transgenic mice were established by ligation of the left anterior descending coronary artery. At one week after intramyocardial injection of Tß4-conjugated SAP, the activation of the epicardium was assessed. At four weeks after implantation, the migration and differentiation of epicardium-derived cells (EPDCs) as well as angiogenesis, lymphangiogenesis and myocardial regeneration were examined. Results: We found that the designer RADA-RPR bound Tß4 and adhered to EPDCs and that Tß4 released from the functionalized SAP could effectively activate the epicardium and induce EPDCs to differentiate towards cardiovascular cells as well as lymphatic endothelial cells. Moreover, SAP-released Tß4 (SAP-Tß4) promoted proliferation of cardiomyocytes. Furthermore, angiogenesis, lymphangiogenesis and myocardial regeneration were enhanced in the MI models at 4 weeks after delivery of SAP-Tß4 along with attenuation of adverse myocardial remodeling and significantly improved cardiac function. Conclusions: These results demonstrate that sustained release of Tß4 from the functionalized SAP can activate the epicardium and effectively enhance the repair of infarcted myocardium. We believe the delivery of SAP-Tß4 may be a promising strategy for MI therapy.

Guanxin Danshen Formulation improved the effect of mesenchymal stem cells transplantation for the treatment of myocardial infarction probably via enhancing the engraftment.

Although intravenous injection is the most convenient and feasible approach for mesenchymal stem cells (MSCs) delivery, the proportion of donor stem cells in the target myocardium after transplantation is small. It is believed that TCM enhances the effect of stem cell therapy by improving the hostile microenvironment and promoting the migration and survival of stem cells. Guanxin Danshen (GXDS) formulation is one of the main prescriptions for clinical treatment of ischemic heart diseases in China. The purpose of this study was to evaluate the effects of GXDS formulation administration combined with MSCs transplantation on cardiac function improvement, apoptosis, angiogenesis and survival of transplanted cells in an acute model of acute myocardial infarction (MI). After being labeled with GFP, MSCs were transplanted via intravenous injection. Meanwhile, GXDS dripping pills were given by intragastric administration for 4 weeks from 2 days before MI. Echocardiography showed moderate improvement in cardiac function after administration of GXDS formulation or intravenous transplantation of MSCs. However, GXDS formulation combined with MSCs transplantation significantly improved cardiac function after MI. The myocardial infarct size in rats treated with MSCs was similar to that in rats treated with GXDS formulation. However, GXDS formulation combined with MSCs transplantation significantly reduced infarction area. In addition, GXDS formulation combined with MSCs transplantation not only decreased cell apoptosis according to the TUNEL staining, but also enhanced angiogenesis in the peri-infarction and infarction area. Interestingly, the use of GXDS formulation increased the number of injected MSCs in the infarct area. Furthermore, GXDS formulation combined with MSCs transplantation increased SDF-1 levels in the infarcted area, but did not affect the expression of YAP. Our study provided a more feasible and accessible strategy to enhance the migration of stem cells after intravenous injection by oral administration of GXDS formulation. The combination of GXDS formulation and stem cell therapy has practical significance and application prospects in the treatment of ischemic cardiomyopathy such as MI.

Self-assembling peptide modified with QHREDGS as a novel delivery system for mesenchymal stem cell transplantation after myocardial infarction.

The lower cell survival and retention in the hostile microenvironment after transplantation has been implicated as a major bottleneck in the advancement of stem cell therapy for myocardial infarction (MI). In this study, we designed a novel self-assembling peptide (SAP) by attaching prosurvival peptide QHREDGS derived from angiopoeitin-1 to the known SAP, RADA16-I. The mesenchymal stem cells (MSCs) were harvested from male rats and cytoprotective effect of this designer SAP (DSAP) on cultured MSCs was detected by Hoechst 33342 staining after being exposed to oxygen and glucose deprivation (OGD). The cytoprotective effect of MSCs seeded in DSAP (DSAP-MSCs) on OGD treated cardiomyocytes was examined by TUNEL staining, phosphorylated (p-) protein kinase B (Akt) level, and ELISA. The therapeutic potential of MSC transplantation carried in DSAP was evaluated in a female rat MI model. PBS, MSCs alone, MSCs seeded in SAP (SAP-MSCs), or DSAP-MSCs were transplanted into the border of the infarcted area, respectively. DSAP not only increased the proliferation of MSCs and decreased apoptosis of MSCs after OGD treatment but also promoted the secretion of IGF-1 and HGF in MSCs. Treatment with culture supernatant of DSAP-MSCs markedly reduced the percentage of apoptotic cardiomyocytes and increased the level of p-Akt. Compared with the MSC group and SAP-MSC group, DSAP-MSC injection improved cardiac function and reduced infarct size, collagen content, and cell apoptosis. The number of Y chromosome-positive cells and microvessels in the DSAP-MSC group was higher than those in the MSC group and SAP-MSC group. Moreover, DSAP-MSC transplantation down-regulated the expression of IL-6 and IL-1ß and up-regulated the level of VEGF and HGF. Interestingly, miR-21 was enriched in DSAP-MSC-derived exosomes (DSAP-MSC-Exos) and the protection against cardiomyocyte apoptosis by DSAP-MSC-Exos was inhibited when miR-21 was knocked down. Furthermore, miR-21 contributed to the improvement of cardiac function after DSAP-MSC-Exo injection in a rat model of MI. Additionally, the combination of DSAP and cardiotrophin-1 (Ctf1) pretreatment further improved the survival of MSCs and the efficiency of MSC transplantation. We proposed QHREDGS-modified SAP as an effective cell delivery system and demonstrated that MSC transplantation in this DSAP promoted angiogenesis and paracrine, thereby reducing scar size and cell apoptosis as well as improving cardiac function probably via exosome-mediated miR-21 after MI. Furthermore, for the first time, we proposed that DSAP, especially working together with Ctf1 pretreatment, could be a valuable way to improve the survival of MSCs and the efficiency of MSC transplantation after MI.-Cai, H., Wu, F.-Y., Wang, Q.-L., Xu, P., Mou, F.-F., Shao, S.-J., Luo, Z.-R., Zhu, J., Xuan, S.-S., Lu, R., Guo, H.-D. Self-assembling peptide modified with QHREDGS as a novel delivery system for mesenchymal stem cell transplantation after myocardial infarction.

Exosomes derived from hypoxia-preconditioned mesenchymal stromal cells ameliorate cognitive decline by rescuing synaptic dysfunction and regulating inflammatory responses in APP/PS1 mice.

Administration of exosomes derived from mesenchymal stromal cells (MSCs) could improve some neurologic conditions by transferring functional biomolecules to recipient cells. Furthermore, exosomes from hypoxic progenitor cells exerted better therapeutic effects in organ injury through specific cargoes. However, there are no related reports about whether exosomes derived from MSCs or hypoxia-preconditioned MSCs (PC-MSCs) could prevent memory deficits in Alzheimer disease (AD). In this study, the exosomes derived from MSCs or PC-MSCs were systemically administered to transgenic APP/PS1 mice. The expression of miR-21 in MSCs was significantly increased after hypoxic treatment. Injection of exosomes from normoxic MSCs could rescue cognition and memory impairment according to results of the Morris water maze test, reduced plaque deposition, and Aß levels in the brain; could decrease the activation of astrocytes and microglia; could down-regulate proinflammatory cytokines (TNF-α and IL-1ß); and could up-regulate anti-inflammatory cytokines (IL-4 and -10) in AD mice, as well as reduce the activation of signal transducer and activator of transcription 3 (STAT3) and NF-κB. Compared to the group administered exosomes from normoxic MSCs, in the group administered exosomes from PC-MSCs, learning and memory capabilities were significantly improved; the plaque deposition and Aß levels were lower, and expression of growth-associated protein 43, synapsin 1, and IL-10 was increased; and the levels of glial fibrillary acidic protein, ionized calcium-binding adaptor molecule 1, TNF-α, IL-1ß, and activation of STAT3 and NF-κB were sharply decreased. More importantly, exosomes from PC-MSCs effectively increased the level of miR-21 in the brain of AD mice. Additionally, replenishment of miR-21 restored the cognitive deficits in APP/PS1 mice and prevented pathologic features. Taken together, these findings suggest that exosomes from PC-MSCs could improve the learning and memory capabilities of APP/PS1 mice, and that the underlying mechanism may lie in the restoration of synaptic dysfunction and regulation of inflammatory responses through regulation of miR-21.-Cui, G.-H., Wu, J., Mou, F.-F., Xie, W.-H., Wang, F.-B., Wang, Q.-L., Fang, J., Xu, Y.-W., Dong, Y.-R., Liu, J.-R., Guo, H.-D. Exosomes derived from hypoxia-preconditioned mesenchymal stromal cells ameliorate cognitive decline by rescuing synaptic dysfunction and regulating inflammatory responses in APP/PS1 mice.

Thymosin ß4 promotes the survival and angiogenesis of transplanted endothelial progenitor cells in the infarcted myocardium.

The survival of transplanted stem cells in ischemic tissue is poor. In the present study, the effects of thymosin ß4 (Tß4) on the survival and angiogenesis of endothelial progenitor cells (EPCs) and improvement in cardiac functions after transplantation of Tß4-treated EPCs in the infarcted myocardium were investigated. EPCs were isolated from bone marrow of adult male rats and incubated in Endothelial Basal Medium-2. Then the cells were treated with Tß4 at different concentrations (0.05, 0.1 and 0.2 µM), and cells incubated with DMEM were set as controls. MTT assay, Transwell assay and tube formation in Matrigel were used to detect cell viability, migration and angiogenesis, respectively. For examining the protective effect of Tß4 on EPCs, the cells were also incubated in the condition of hypoxia and serum deprivation. p-Akt expression was also examined using western blot analysis. Rat models of myocardial infarction (MI) were established by ligation of the anterior descending branch of the left coronary artery. At four weeks after intramyocardial injection of Tß4-treated EPCs, the changes in cardiac functions, size of the scar tissue and density of microvessels were examined by echocardiography, Masson's trichrome staining, immunohistochemistry and fluorescence in situ hybridization (FISH) for the Y-chromosome. Tß4 enhanced EPC viability, protected the cells from apoptosis in hypoxia and serum deprivation, and promoted the proliferation and migration of the cells and formation of capillary-like structures in the cells. Moreover, Tß4 increased p-Akt expression in the cells. The cytoprotective and proangiogenic effects of Tß4 were in a dose-dependent manner. Tß4-treated EPCs improved cardiac function, enhanced the repair of the infarcted myocardium, and promoted angiogenesis after transplantation in the infarcted myocardium. In conclusion, pretreatment of EPCs with Tß4 is a novel strategy for the repair of ischemic tissue after transplantation in MI.

Mesenchymal stem cell-loaded cardiac patch promotes epicardial activation and repair of the infarcted myocardium.

Cardiac patch is considered a promising strategy for enhancing stem cell therapy of myocardial infarction (MI). However, the underlying mechanisms for cardiac patch repairing infarcted myocardium remain unclear. In this study, we investigated the mechanisms of PCL/gelatin patch loaded with MSCs on activating endogenous cardiac repair. PCL/gelatin patch was fabricated by electrospun. The patch enhanced the survival of the seeded MSCs and their HIF-1α, Tß4, VEGF and SDF-1 expression and decreased CXCL14 expression in hypoxic and serum-deprived conditions. In murine MI models, the survival and distribution of the engrafted MSCs and the activation of the epicardium were examined, respectively. At 4 weeks after transplantation of the cell patch, the cardiac functions were significantly improved. The engrafted MSCs migrated across the epicardium and into the myocardium. Tendency of HIF-1α, Tß4, VEGF, SDF-1 and CXCL14 expression in the infarcted myocardium was similar with expression in vitro. The epicardium was activated and epicardial-derived cells (EPDCs) migrated into deep tissue. The EPDCs differentiated into endothelial cells and smooth muscle cells, and some of EPDCs showed to have differentiated into cardiomyocytes. Density of blood and lymphatic capillaries increased significantly. More c-kit+ cells were recruited into the infarcted myocardium after transplantation of the cell patch. The results suggest that epicardial transplantation of the cell patch promotes repair of the infarcted myocardium and improves cardiac functions by enhancing the survival of the transplanted cells, accelerating locality paracrine, and then activating the epicardium and recruiting endogenous c-kit+ cells. Epicardial transplantation of the cell patch may be applied as a novel effective MI therapy.

Stem cell-loaded nanofibrous patch promotes the regeneration of infarcted myocardium with functional improvement in rat model.

Myocardial infarction (MI) leads to the loss of cardiomyocytes, followed by left ventricular (LV) remodeling and cardiac dysfunction. The authors hypothesize that an elastic, biodegradable nanofibrous cardiac patch loaded with mesenchymal stem cells (MSC) could restrain LV remodeling and improve cardiac function after MI. Poly(ε-caprolactone)/gelatin (PG) nanofibers were fabricated by electrospinning, and the nanofibers displayed a porous and uniform nanofibrous structure with a diameter of 244±51nm. An MI model was established by ligation of the left anterior descending coronary artery of female Sprague-Dawley rats. The PG nanofibrous patch seeded with MSC, isolated from rat bone marrow, was implanted on the epicardium of the infarcted region of the LV wall of the heart. After transplantation, the PG-cell patch restricted the expansion of the LV wall effectively and reduced the scar size, and the density of the microvessels increased. Cells within the patch were able to migrate towards the scar tissue, and promoted new blood vessel formation at the infarct site. Angiogenesis and the cardiac functions improved significantly after 4weeks of implantation. The MSC-seeded PG nanofibrous patches are demonstrated to provide sufficient mechanical support, to induce angiogenesis and to accelerate cardiac repair in a rat model of MI. The study highlights the positive impact of implantation of an MSC-seeded PG nanofibrous patch as a novel constituent for MI repair.

Anion-triggered substituent-dependent conformational switching of salicylanilides. New hints for understanding the inhibitory mechanism of salicylanilides.

A series of salicylanilides (1a-h) bearing varied substituents at the 3'- or 4'-position of the anilino moiety (substituent = p-OCH3, p-CH3, m-CH3, H, p-Cl, m-Cl, p-CO2CH3, and p-CN) were synthesized. In acetonitrile all of the substituted salicylanilides 1a-h predominantly adopt the "closed-ring" conformation facilitated by a strong intramolecular OH...O=C hydrogen bond. In the presence of H2PO4-, the conformation of 1a-h was found to be modulated by the substituent. With our proposed proton-transfer fluorescence probing method, we were able to show that the conformation of 1a-f bearing a not highly electron-withdrawing substituent was switched to the "open-ring" form by H2PO4-, whereas 1h bearing a highly electron-withdrawing substituent, p-CN, remained in the "closed-ring" conformation. The significance of these findings for understanding, from a molecular structural point of view, the mechanism of salicylanilide-based inhibitors for inhibiting the protein tyrosine kinase epidermal growth factor receptor was discussed.

[Exploitation of a signal collection system of a novel intelligent clinical patient monitor based on SoC].

A novel intelligent clinical monitoring system has been exploited based on SoC chip, with the integration of multiple parameters detecting techniques, the combination of the sensor technology and electric circuit technology.