The mechanisms of the chronic pain and depression comorbidity have gained significant attention in recent years. The complement system, widely involved in central nervous system diseases and mediating non-specific immune mechanisms in the body, remains incompletely understood in its involvement in the comorbidity mechanisms of chronic pain and depression. This review aims to consolidate the findings from recent studies on the complement system in chronic pain and depression, proposing that it may serve as a promising shared therapeutic target for both conditions. Complement proteins C1q, C3, C5, as well as their cleavage products C3a and C5a, along with the associated receptors C3aR, CR3, and C5aR, are believed to have significant implications in the comorbid mechanism. The primary potential mechanisms encompass the involvement of the complement cascade C1q/C3-CR3 in the activation of microglia and synaptic pruning in the amygdala and hippocampus, the role of complement cascade C3/C3a-C3aR in the interaction between astrocytes and microglia, leading to synaptic pruning, and the C3a-C3aR axis and C5a-C5aR axis to trigger inflammation within the central nervous system. We focus on studies on the role of the complement system in the comorbid mechanisms of chronic pain and depression.

Neuroinflammation induced by engulfment of synapses by phagocytic microglia plays a crucial role in neuropathic pain. Stauntonia chinensis is extracted from Stauntonia chinensis DC, which has been used as a traditional Chinese medicine to control trigeminal neuralgia or sciatica. However, the specific anti-neuralgia mechanism of Stauntonia chinensis is unknown. In this study, the analgesic effect of Stauntonia chinensis injection (SCI) in mice with neuropathic pain and the possible mechanisms are explored. We find that a local injection of 0.1 mL Stauntonia chinensis for 14 days can considerably relieve mechanical hyperalgesia and thermal hyperalgesia in mice with sciatic chronic constriction injury (CCI). Immunofluorescence staining shows that SCI reduces neuroinflammation in the spinal cord of CCI mice. RNA sequencing reveals that the expression of postsynaptic density protein 95 (PSD-95), a postsynaptic scaffold protein, is downregulated in the spinal cord of CCI mice, but upregulated after SCI administration. Immunofluorescence experiments also demonstrate that SCI administration reverses microglia proliferation and PSD-95 downregulation in CCI mice. These data suggest that SCI relieves neuropathic pain by increasing the expression of PSD-95 and reducing the proliferation of phagocytic microglia.

The molecular mechanisms of refractory pain in postherpetic neuralgia (PHN) patients are not fully understood. PHN may be related to skin abnormality after herpes zoster induced skin lesions. We previously reported 317 differentially expressed microRNAs (miRNAs) in PHN skin compared with the contralateral normal mirror skin. In this study, 19 differential miRNAs were selected and the expression was validated in other 12 PHN patients. The expression levels of miR-16-5p, miR-20a-5p, miR-505-5p, miR-3664-3p, miR-4714-3p and let-7a-5p are lower in PHN skin, which is the same as those in microarray experiment. To evaluate the effects of cutaneous miRNA on PHN, the expression of candidate miRNAs is further observed in resiniferatoxin (RTX) induced PHN-mimic mice model. In the plantar skin of RTX mice, miR-16-5p and let-7a-5p are downregulated, with the same expression trend of PHN patients. In addition, intraplantar injection of agomir-16-5p reduced mechanical hyperalgesia, and improved thermal hypoalgesia in RTX mice. Furthermore, agomir-16-5p down-regulated the expression levels of Akt3, which is the target gene of agomir-16-5p. These results suggest that intraplantar miR-16-5p may alleviate RTX induced PHN-mimic pain by inhibiting the expression of Akt3 in the skin.

Background: Neoatherosclerosis (NA) is associated with stent failure. However, systematic studies on the manifestations of NA and neovascularization (NV) at different stages after drug-eluting stent (DES) implantation are lacking. Moreover, the relationship between NA and NV in in-stent restenosis (ISR) has not been reported. This study aimed to characterize NA and NV in patients with ISR at different post-DES stages and compare the association between NA and NV in ISR lesions. Methods: A total of 227 patients with 227 lesions who underwent follow-up optical coherence tomography before percutaneous coronary intervention for DES ISR were enrolled and divided into early (E-ISR: <1 year), late (L-ISR: 1-5 years), and very-late (VL-ISR: >5 years) ISR groups. Furthermore, ISR lesions were divided into NV and non-NV groups according to the presence of NV. Results: The prevalence of NA and NV was 52.9% and 41.0%, respectively. The prevalence of lipidic NA (E-ISR, 32.7%; L-ISR, 50.0%; VL-ISR, 58.5%) and intimal NV (E-ISR, 14.5%; L-ISR, 30.8%; VL-ISR, 38.3%) increased with time after stenting. NA was higher in ISR patients with NV lesions than in those without (p < 0.001). Patients with both ISR and NV had a higher incidence of macrophage infiltration, thin-cap fibroatheroma, intimal rupture, and thrombosis (p < 0.01). Conclusions: Progression of lipidic NA was associated with L-ISR and VL-ISR but may not be related to calcified NA. NA was more common in ISR lesions with NV; its formation may substantially promote NA progression and plaque instability.

目的 探讨以问题为导向的教学(PBL)联合以病例为基础的教学(CBL)模式在心内科住院医师规范化培训中的应用效果.方法 选取在本院心内科轮转的68名内科规培学员随机分为对照组(n=34)和观察组(n=34),对照组进行传统的教学方法,而观察组进行CBL联合PBL的教学模式,3个月后,对两组学生进行理论知识及实践技能考核并同时对带教老师和规培医师发放调查问卷进行满意度调查.结果 (1)观察组的理论成绩和专业技能成绩均显著高于对照组(P<0.001);(2)观察组的带教老师和规培医师对PBL联合CBL教学模式的反馈评价更高(P<0.05).结论 PBL联合CBL教学法有助于提高心内科规培医师的临床综合能力,提高临床带教质量,该方法值得在临床实践中推广.

SCN5 A基因编码心脏钠离子通道Nav1.5的α亚基,主要与心脏动作电位的快速去极化有关,是最早研究的离子通道之一.SCN5 A的突变和众多遗传性心脏疾病的电生理和结构表型有很大的相关性.其功能丧失突变与Brugada综合征、进行性心脏传导障碍、病窦综合征、特发性心室颤动和心房静止有关,而功能获得突变与长QT综合征3型相关.其他与SCN5 A相关的疾病,如心房颤动,婴儿猝死综合征,扩张型心肌病,以及致心律失常性右室心肌病,重叠综合症,都有更复杂的病理生理机制,涉及多种分子表型的变化.随着膜片钳技术和诱导多能干细胞定向分化为心肌细胞(iPSC-CMS)技术的发展,SCN5A基因突变导致遗传性心脏疾病的致病机制已取得较大进展,根据最近的发现,本文主要对近年来SCN5 A基因突变导致各种遗传性心脏疾病中的研究进展做一总结.

目的 骨髓间充质干细胞(BMSCs)能够在多种心血管疾病病理过程中发挥重要作用,但其对支架内再狭窄的影响有待进一步研究.文中旨在探讨BMSCs源外泌体对大鼠颈动脉球囊损伤后新生内膜增殖的影响及circRNA和microRNA表达变化.方法 采用差速超速离心法提取大鼠BMSCs源外泌体,并使用Western blot及透射电镜对其进行鉴定.采用球囊损伤大鼠颈动脉的方法建立血管内膜增生动物模型,将36只成年雄性SD大鼠随机分为:假手术组、损伤组、外泌体组(400μL);假手术组大鼠只分离颈左总动脉血管,其余各组大鼠的左颈总动脉均行球囊损伤,外泌体组行球囊损伤后立即原位注射400μL BMSCs源外泌体并用微型血管夹夹闭血管5 min.采用HE染色检测内膜增生情况,DCFH-DA染色检测血管活性氧(ROS)释放情况.采用circRNA和microRNA芯片筛查差异表达的circRNA和microRNA,并以每组3个样本对其中显著差异的8个circRNA和7个microRNA进行qRT-PCR验证,并筛选出BMSCs源外泌体处理后差异表达的circRNA和microRNA;生物信息学方法预测差异microRNA的靶基因,并进行GO分析和KEGG通路分析,构建circRNA-microRNA-mRNA共表达网络,对其潜在分子机制进行探讨.结果 透射电镜及Western blot验证提取的囊泡状物质为外泌体;HE染色结果显示:损伤组较假手术组新生内膜增殖明显,其内膜/中膜面积比(1.902±0.217)较假手术组(1.000±0.000)显著增加(P<0.05);外泌体组较损伤组新生内膜增殖程度有所减低,其内膜/中膜面积比(0.982±0.067)较损伤组明显减低(P<0.05).DCFH-DA染色结果显示:与假手术组DCFHA红色荧光强度(4.730±0.104)相比,损伤组(16.800±0.380)明显增强(P<0.05);与损伤组相比,外泌体组DCFHA红色荧光强度(12.810±0.094)明显减弱(P<0.05).circRNA芯片显示差异性表达的circRNA共1683个(Fold change≥2,P<0.05).与假手术组相比,损伤组中上调的有631个,下调的有1052个.microRNA芯片显示有差异microRNA共44个(Fold change≥2,P<0.05),且均在损伤组上调.GO分析和KEGG分析表明,microRNA的预测靶基因参与了细胞生物学进程正向调控、细胞间紧密连接、激酶活性等方面有关,并在MAPK信号通路、Ras信号通路、Hippo信号通路等等中富集.结合芯片和qRT-PCR结果,筛选出BMSCs源外泌体处理后损伤颈动脉组织中差异表达明显的有circRNA_004976、circRNA_008565、circRNA_017449以及miR-20a-5p、miR-146a-5p、miR-21-5p(P<0.05).结论 BMSCs源外泌体可以抑制大鼠颈动脉球囊损伤后内膜增生,其潜在机制可能与circRNA_004976、circRNA_008565以及miR-20a-5p、miR-21-5p等分子调控细胞增殖、迁移有关.

Background: The in-hospital mortality of patients with ST-segment elevation myocardial infarction (STEMI) increases to more than 50% following a cardiogenic shock (CS) event. This study highlights the need to consider the risk of delayed calculation in developing in-hospital CS risk models. This report compared the performances of multiple machine learning models and established a late-CS risk nomogram for STEMI patients. Methods: This study used logistic regression (LR) models, least absolute shrinkage and selection operator (LASSO), support vector regression (SVM), and tree-based ensemble machine learning models [light gradient boosting machine (LightGBM) and extreme gradient boosting (XGBoost)] to predict CS risk in STEMI patients. The models were developed based on 1,598 and 684 STEMI patients in the training and test datasets, respectively. The models were compared based on accuracy, the area under the curve (AUC), recall, precision, and Gini score, and the optimal model was used to develop a late CS risk nomogram. Discrimination, calibration, and the clinical usefulness of the predictive model were assessed using C-index, calibration plotd, and decision curve analyses. Results: A total of 2282 STEMI patients recruited between January 1, 2016 and May 31, 2020, were included in the complete dataset. The linear models built using LASSO and LR showed the highest overall predictive power, with an average accuracy over 0.93 and an AUC above 0.82. With a C-index of 0.811 [95% confidence interval (CI): 0.769-0.853], the LASSO nomogram showed good differentiation and proper calibration. In internal validation tests, a high C-index value of 0.821 was achieved. Decision curve analysis (DCA) and clinical impact curve (CIC) examination showed that compared with the previous score-based models, the LASSO model showed superior clinical relevance. Conclusions: In this study, five machine learning methods were developed for in-hospital CS prediction. The LASSO model showed the best predictive performance. This nomogram could provide an accurate prognostic prediction for CS risk in patients with STEMI.

OBJECTIVE:To assess the expression of inflammatory cytokines in the affected and normal skin of postherpetic neuralgia (PHN) patients.METHODS:Affected skin and normal skin samples were collected from PHN patients. Inflammatory cell infiltration in the dermis were evaluated by hematoxylin-eosin (HE) staining. A human inflammatory protein array containing 40 cytokines was used to assess expression differences between PHN and control skin. Enzyme linked immunosorbent assay (ELISA) kits were used to confirm cytokine expression in 10 PHN patients.RESULTS:HE staining showed that the epidermis of PHN skin was thicker than that of contralateral normal skin. Compared with normal skin, there was more infiltration of inflammatory cells into the dermis of PHN skin. The cytokine array detected the presence of 21/40 cytokines; however, only interleukin (IL)-1α showed differential expression between PHN skin and normal skin. ELISA results for IL-1α, IL-16, intercellular adhesion molecule-1, and monocyte chemoattractant protein-1 were consistent with those of cytokine arrays.CONCLUSIONS:Expression of inflammatory cytokines in PHN skin was not significantly altered compared with normal skin. Chronic refractory pain in PHN is not necessarily associated with increased inflammation in the affected skin.

Objective To investigate the effect of long noncoding RNA (LncRNA) LOC100360491 on apoptosis of H9c2 cardiomyocytes induced by hypoxia-reoxygenation injury and explore the possible mechanism. Methods H9c2 cells were infected with lentiviral vectors carrying LOC100360491 gene or its inhibitor (shLncRNA) or with a negative control vector, and the changes in LOC100360491 expression in the cells were detected by qRT-PCR. The infected H9c2 cells were exposed to hypoxia for 24 h followed by reoxygenation for 6 h, and early apoptosis and reactive oxygen species (ROS) production of the cells were analyzed by flow cytometry. The expression of pro-caspase-3, cleaved caspase-3, Bax, and Bcl-2 proteins in the cells were detected using Western blotting; the cellular expression levels of PAK3 and CNNM2 mRNA were detected using qRT-PCR. Results The results of qRT-PCR confirmed successful overexpression or inhibition of LOC100360491 in H9c2 cells (P < 0.05). Compared with the cells infected with the control lentiviral vector, the cells with lentivirus-mediated LOC100360491 overexpression showed significantly decreased early apoptosis and ROS production with obviously down-regulated expressions of cleaved caspase-3 and Bax and up-regulated Bcl-2 expression following hypoxia-reoxygenation (P < 0.05). Inhibition of LOC100360491 in H9c2 cells resulted in the opposite changes, which were not significant compared with negative control group. Compared with the cells infected with the negative control vector, the cells with LOC100360491 suppression showed significantly down-regulated expressions of PAK3 and CNNM2 mRNA (P < 0.05), while LOC100360491 overexpression resulted in obviously up-regulated PAK3 expression (P < 0.05) without significantly affecting CNNM2 expression. Conclusion Overexpression of LOC100360491 inhibits apoptosis of H9c2 cells induced by hypoxia-reoxygenation possibly by inhibiting mitochondrial release of ROS through upregulating the transcription of PAK3.

目的 研究对心内科实习护士实施WPBL教学模式的效果.方法 选取医院心内科实习护士45例展开研究,时间跨度为2018年5月—2018年9月,按模式差异分为对照(常规教学)和观察组(WPBL模式),对比分析两组实习护士学习效果、对心内科理论知识和护理技能掌握程度.结果 观察组带教后心内科疾病认知和兴趣(8.11±1.01)分,自主学习能力(7.36±1.11)分,学习效率(7.24±1.21)分,独立思考能力(7.75±1.36)分,护患沟通能力(8.11±1.11)分,临床基础能力(8.44±1.03)分,自身批判性行为(7.25±1.44)分学习效果各项评分明显较对照组高,P<0.05.观察组理论知识掌握度95.5％,护理技能掌握度95.5％,对照组分别为73.9％和69.6％,P<0.05.结论 对心内科实习护士实施WPBL教学效果显著,值得推广.

Objective To investigate the regulatory effect of bone marrow mesenchymal stem cells (BMSCs) derived exosomes on intimal hyperplasia and expression of long non-coding RNAs (lncRNAs) in rat model of carotid artery balloon injury and its potential mechanism. Methods Rat BMSCs-derived exosomes were extracted from male SD rats by differential centrifugation, and then identified by Western blotting and transmission electron microscopy. Then a total of 36 male SD rats were randomly divided into sham-operation group, model group (carotid artery balloon injury), and model+exosome treatment group (in situ injection of 400 μL 0.25 μg/μL exosomes), with 12 rats in each group. In 14 d after the treatment, all rats were sacrificed to harvest the carotid artery. HE staining was used to observe the intima/media (I/M) area ratio of carotid artery. Immunohistochemical assay was used to detect the expression of PCNA, and Western blotting was applied for the expression of the proteins involved in the intimal proliferation and phenotypic transformation. LncRNA-mRNA co-expression microarray and bioinformatics analysis were employed to analyze the differentially expressed lncRNAs and mRNAs in carotid artery tissues of the rats from the sham operation group and the model group for the potential molecular mechanism. qRT-PCR was performed to detect the expression of candidate lncRNAs in the carotid artery tissues. Results Transmission electron microscopy displayed that the BMSCs-derived exosomes presented "coaster-like" changes. Western blotting results confirmed that CD63, Alix and HSP70 were expressed in the extracted exosomes. The treatment of BMSCs-derived exosomes resulted in significant reduce in the I/M area ratio of carotid artery (P < 0.05) and decreased expression of proliferation-related proteins PCNA and Cyclin D1 (P < 0.05). The results of lncRNA-mRNA co-expression microarray showed that there were 1 083 up- and 629 down-regulated lncRNAs, and 2 004 up- and 2 487 down-regulated mRNA (Fold change>2.0, P < 0.05) in the model group when compared with the sham operation group. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that these multiple lncRNAs were correlated with mRNAs, and the corresponding target mRNAs are involved in many biological processes, such as vascular smooth muscle contraction, actin cytoskeleton regulation and cell cycle, which are related to the mechanism of vascular restenosis after balloon injury. In combination with bioinformatics analysis, qRT-PCR detected 7 lncRNAs with significant differential expression, and the results showed that XR_593268 was up-regulated (P < 0.05), and XR_602080, XR_602012 and XR_591017 were down-regulated (P < 0.05) in the exosome treatment group compared with the model group. Conclusion The BMSCs-derived exosomes inhibit intimal hyperplasia in rats after balloon injury of carotid artery. The potential mechanism may be related to the regulation of smooth muscle cell cycle changes by lncRNAs XR_602080 and XR_591017 through Gsk3b, Cdkn2b and Ccna2.

Exosomes play critical roles in mediating cell-to-cell communication by delivering noncoding RNAs (including miRNAs, lncRNAs, and circRNAs). Our previous study found that cardiomyocytes (CMs) subjected to hypoxia released circHIPK3-rich exosomes to regulate oxidative stress damage in cardiac endothelial cells. However, the role of exosomes in regulating angiogenesis after myocardial infarction (MI) remains unknown. The aim of this study was to establish the effects of exosomes derived from hypoxia-induced CMs on the migration and angiogenic tube formation of cardiac endothelial cells. Here, we reported that hypoxic exosomes (HPC-exos) can effectively reduce the infarct area and promote angiogenesis in the border surrounding the infarcted area. HPC-exos can also promote cardiac endothelial cell migration, proliferation, and tube formation in vitro. However, these effects were weakened after silencing circHIPK3 in hypoxia-induced CMs. We further verified that silencing and overexpressing circHIPK3 changed cardiac endothelial cell proliferation, migration, and tube formation in vitro by regulating the miR-29a expression. In addition, exosomal circHIPK3 derived from hypoxia-induced CMs first led to increased VEGFA expression by inhibiting miR-29a activity and then promoted accelerated cell cycle progression and proliferation in cardiac endothelial cells. Overexpression of miR-29a mimicked the effect of silencing circHIPK3 on cardiac endothelial cell activity in vitro. Thus, our study provides a novel mechanism by which exosomal circRNAs are involved in the communication between CMs and cardiac endothelial cells.

Background: Mechanisms of neuropathic pain are not fully understood. Molecular changes in spinal dorsal horn take part in the initiation and development of neuropathic pain. Methods: To detect the transcriptome changes in the dorsal spinal cord of neuropathic pain rat, sciatic nerve chronic constriction injury (CCI) rats were used. Then, the CCI ipsilateral dorsal spinal cords of lumbar L3-L5 segments were collected at 14th day post-CCI and subjected to microRNA and long non-coding RNA (lncRNA)/mRNA microarray. To evaluate functions of differential mRNAs, bioinformatics methods including gene ontology (GO) and KEGG pathway analysis were conducted for significantly up- and downregulated mRNAs. Results: MicroRNA microarrays showed that 13 microRNAs were differently expressed between CCI and sham-operated rats (fold change >= 2.0). Six of them were upregulated, and the other seven were downregulated in CCI group. MicroRNA-1b overexpressed 18.7 times after CCI. LncRNA/mRNA microarray detected 876 lncRNAs with significant differential expression (fold change >= 2.0). Among them, 339 were significantly upregulated, and 537 were downregulated in CCI group. Sixteen of them differentially expressed more than 10 times and the 1ncRNA XR_356687 overexpressed as high as 53 times. In addition, 950 mRNAs were differentially expressed (fold change >= 2.0), including 405 upregulated and 545 downregulated in CCI group. Ten of these mRNAs with changed expressions of more than 10 times. The Hspa1b (encodes heat shock protein 70) overexpressed 24 times in CCI rats. Gene ontology analysis revealed that hundreds of differentially expressed mRNAs involved in the biological processes, cellular component, and molecular function. In addition, these genes significantly enriched into 32 KEGG pathways, including the TNF, FoxO, cytokine-cytokine receptor interaction, and calcium signaling pathways. Conclusion: Neuropathic pain induced comprehensive changes of transcription profile in the dorsal spinal cord. These differentially expressed transcripts in spinal cord could be potential targets in defeating neuropathic pain.

目的:探讨急性冠状动脉综合征(ACS)患者冠状动脉(冠脉)闭塞与非闭塞的临床特征及院内预后差异.方法:将ACS患者分为冠脉闭塞组及冠脉非闭塞组,收集患者的临床资料并进行统计分析.结果:共有ACS患者592例,其中66例(11％)继发性ACS患者被排除,最后526例患者(闭塞组303例,非闭塞组223例)纳入分析.与冠脉闭塞组相比,非闭塞组胸痛时间(20.87±57.74)h∶(10.38±11.58)h、收缩压(128.15±25.02) mmHg∶(122.06±23.57) mmHg、血脂异常(18％∶ 11％)、阿司匹林(96％∶87％)、P2Y12抑制剂(96％;87％)、他汀类药物(97％∶90％)、β受体阻断剂(74％∶63％)、左室射血分数(EF)(50.68±11.05)％∶(46.98±11.12)％、LAD病变(62％∶45％)及输血(2％∶0)更高,均P＜0.05;而Mb(408.24±617.75)ng/L∶(628.22±755.60) ng/L、RCA病变(19％∶38％)、PTCA(2％∶ 7％)、血栓抽吸(6％∶21％)、替罗非班(60％∶79％)、支架直径(3.07±0.48) mm∶(3.16±0.45)mm、全因死亡(0∶5％)、再次心梗(0∶3％)、心力衰竭(4％∶12％)、心源性休克(4％∶9％)及全因事件(16％∶32％)更低,均P＜0.05.结论:与冠脉闭塞患者相比,冠脉非闭塞的ACS患者胸痛时间、收缩压、血脂异常病史、药物使用(阿司匹林、P2Y12抑制剂、他汀类药物及β受体阻断剂)及LAD病变更高,院内预后更好.

Mechanisms of postherpetic neuralgia (PHN) are still not clear. Transcripts such as microRNA (miRNA) and circular RNA (circRNA) in the affected skin may take part in the initiation and development of this neuropathic pain; however, their expression profiles in skins of PHN patients have not been reported. The PHN affected skin and the mirror skin were collected and subjected to miRNA and circRNA microarray, and expression profiles were comparatively analyzed. There were 317 differently expressed miRNAs in PHN affected skin compared with mirror skin (fold change >= 2.0), and 13 of them showed fold change >10 in the PHN skin. Only one circRNA, hsa_circRNA_405463 showed fold change >2 in PHN skin, however, 31 circRNAs with fold change >= 1.5. To evaluate functions of differential miRNAs, their target mRNAs were predicted and bioinformatics analyses including gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway were conducted. Target mRNAs significantly (P<0.05) enriched in 85 pathways, such as FoxO, AMPK, MAPK and pathway. These data reported for the first time that miRNA and circRNA differentially expressed in the PHN skin and these transcripts with abnormal expression could be potential targets to treat PHN.

AIM:To explore the effect of microRNA (miR)-21 on proliferation, migration and differentiation abilities of c-Kit+ cardiac stem cells (CSCs). METHODS:c-Kit+ CSCs were cultured and selected by the methods of en-zyme digestion and magnetic bead separation. miR-21 mimics (50 nmol/L) and mimics negative control ( MNC) were transfected into c-Kit+CSCs with Lipofectamine?2000. The cells was divided into 3 groups:control group:c-Kit+ CSCs without any pretreatment; MNC group:the cells were transfected with MNC for 48 h; mimics group:the cells were trans-fected with miR-21 mimics for 48 h. qPCR was used to assess the expression of miR-21 in each group. CCK-8 and EdU as-says were used to determine the cell proliferation. qPCR and immunofluorescence were used to detect the differentiation in each group. Scratch assay was adopted to explore the migration ability of the cells. RESULTS:The expression of c-Kit in the c-Kit+ CSCs were 90.8%, with 0.6% of CD45 and 0.5% of CD34. A significant increase in miR-21 expression was observed when the cells were transfected with miR-21 mimics for 48 h ( P<0.05). CCK-8 and EdU assays showed that miR-21 significantly increased cell proliferation as compared with MNC group and control group (P<0.05). No difference in the expression of Nkx2.5, CD31 and α-SMA at mRNA and protein levels was observed, and no difference of the migra-tion ability in 3 groups of the c-Kit+ CSCs was found. CONCLUSION:Over-expression of miR-21 significantly promotes the proliferation of c-Kit+ CSCs, without any effect on the cell migration and differentiation.

Stem cell (SC) therapy for ischemic cardiomyopathy is hampered by poor survival of the implanted cells. Recently, SC-derived exosomes have been shown to facilitate cell proliferation and survival by transporting various proteins and non-coding RNAs (such as microRNAs and lncRNAs). In this study, miR-21 was highly enriched in exosomes derived from bone marrow mesenchymal stem cells (MSCs). Interestingly, exosomes collected from hydrogen peroxide (H2O2)-treated MSCs (H-Exo) contained higher levels of miR-21 than exosomes released from MSCs under normal conditions (N-Exo). The pre-treatment of C-kit+ cardiac stem cells (CSCs) with H-Exos resulted in significantly increased levels of miR-21 and phosphor-Akt (pAkt) and decreased levels of PTEN, which is a known target of miR-21. AnnexinV-FITC/PI analysis further demonstrated that the degree of oxidative stress-induced apoptosis was markedly lower in H-Exo-treated C-kit+ CSCs than that in N-Exo-treated cells. These protective effects could be blocked by both a miR-21 inhibitor and the PI3K/Akt inhibitor LY294002. Therefore, exosomal miR-21 derived from H2O2-treated MSCs could be transported to C-kit+ cardiac stem cells to functionally inhibit PTEN expression, thereby activating PI3K/AKT signaling and leading to protection against oxidative stress-triggered cell death. Thus, exosomes derived from MSCs could be used as a new therapeutic vehicle to facilitate C-kit+ CSC therapies in the ischemic myocardium.

Cardiac stem cells (CSCs) have emerged as one of the most promising stem cells for cardiac protection. Recently, exosomes from bone marrow-derived mesenchymal stem cells (BMSCs) have been found to facilitate cell proliferation and survival by transporting various bioactive molecules, including microRNAs (miRs). In this study, we found that BMSC-derived exosomes (BMSC-exos) significantly decreased apoptosis rates and reactive oxygen species (ROS) production in CSCs after oxidative stress injury. Moreover, a stronger effect was induced by exosomes collected from BMSCs cultured under hypoxic conditions (Hypoxic-exos) than those collected from BMSCs cultured under normal conditions (Nor-exos). We also observed greater miR-214 enrichment in Hypoxic-exos than in Nor-exos. In addition, a miR-214 inhibitor or mimics added to modulate miR-214 levels in BMSC-exos revealed that exosomes from miR-214-depleted BMSCs partially reversed the effects of hypoxia-induced exosomes on oxidative damage in CSCs. These data further confirmed that miR-214 is the main effector molecule in BMSC-exos that protects CSCs from oxidative damage. miR-214 mimic and inhibitor transfection assays verified that CaMKII is a target gene of miR-214 in CSCs, with exosome-pretreated CSCs exhibiting increased miR-214 levels but decreased CaMKII levels. Therefore, the miR-214/CaMKII axis regulates oxidative stress-related injury in CSCs, such as apoptosis, calcium homeostasis disequilibrium, and excessive ROS accumulation. Collectively, these findings suggest that BMSCs release miR-214-containing exosomes to suppress oxidative stress injury in CSCs through CaMKII silencing.