Dual Specificity Phosphatase 3 (DUSP3) Knockdown Alleviates Acute Myocardial Infarction Damage via Inhibiting Apoptosis and Inflammation.

BACKGROUND: Dual Specificity Phosphatase 3 (DUSP3) regulates the innate immune response and is associated with ischemia/reperfusion (I/R). However, the precise function of DUSP3 in acute myocardial infarction (AMI) remains to be established. METHODS: In this study, the AMI model in vivo was established in mice by permanent left anterior descending coronary artery (LAD) occlusion, and primary neonatal mouse cardiomyocytes were treated with hypoxia for 12 hours to mimic AMI in vitro. Sh-DUSP3 and AAV9-sh-DUSP3 were used to knock down the DUSP3 expression. LVEF%, LVFS%, SOD1, and HO-1 level, and TTC staining were used to test the cardiac function. Flow cytometric analysis, Western blot, and TUNEL staining were used to investigate the effect of DUSP3 knockdown on apoptosis. Moreover, we detect inflammatory factors expression and oxidative stress by ELISA. Besides, we investigate DUSP3 expression by RT-qPCR. RESULTS: Our findings determined the role of DUSP3 in the progression of AMI. And demonstrated that DUSP3 knockdown alleviated oxidative stress, inflammation, and apoptosis. In addition, our results indicated that DUSP3 knockdown could regulate the expression of p-NF-κB, ICAM1, and VCAM1. CONCLUSION: Our results demonstrated that the knockdown of DUSP3 could effectively alleviate AMI symptoms and be mediated through the NF-κB signaling pathway.

MiRNA-615-3p Alleviates Oxidative Stress Injury of Human Cardiomyocytes Via PI3K/Akt Signaling by Targeting MEF2A.

BACKGROUND: Myocardial infarction, a coronary heart disease, is a serious hazard to human health. Cardiomyocyte oxidative stress and apoptosis have been considered as the main causes of myocardial infarction. Here, we aimed to investigate the role of miR-615-3p in oxidative stress and apoptosis of human cardiomyocytes. METHODS: Reverse transcription-quantitative polymerase chain reaction was performed to determine miR-615-3p or MEF2A expression in human cardiomyocytes. Apoptosis and viability of human cardiomyocytes were assessed by flow cytometry analysis and CCK-8 assay. In addition, the contents of malondialdehyde, reactive oxygen species, and superoxide dismutase were detected by corresponding commercial kits. The binding of miR-615-3p and MEF2A in human cardiomyocytes was examined by luciferase reporterassay. RESULTS: Hypoxia/reoxygenation treatment downregulated the expression level ofmiR-615-3p in human cardiomyocytes. Overexpressing miR-615-3p increased human cardiomyocyte viability and decreased human cardiomyocyte apoptosis. Moreover, miR- 615-3p mimics suppressed oxidative stress in hypoxia/reoxygenation-stimulated human cardiomyocytes. MEF2A was confirmed as a target gene of miR-615-3p and was highly expressed in hypoxia/reoxygenation-stimulated human cardiomyocytes, and its upregu-lation partially reversed the influence of miR-615-3p mimics on oxidative stress and apop-tosis of human cardiomyocytes. Moreover, miR-615-3p inactivated the P13K/Akt pathway by inhibiting MEF2A. CONCLUSIONS: Overexpression of miR-615-3p protects human cardiomyocytes from oxida-tive stress injury by targeting MEF2A via the PI3K/Akt signaling.

Saprirearine protects H9c2 cardiomyocytes against hypoxia/reoxygenation-induced apoptosis by activating Nrf2.

Myocardial infarction is a major cause of mortality and disability worldwide. Ischemia/reperfusion injury is the key factor that results in the increase in infarct size in pathogenesis. To find a novel therapy for myocardial infarction, we have evaluated saprirearine, a natural diterpenoid, using H9c2 cardiomyocytes injured by hypoxia/reoxygenation and explored the possible mechanisms. The results showed that saprirearine improved cell survival by increasing cell viability and blocking the release of lactate dehydrogenase. Meanwhile, saprirearine was found to attenuate mitochondrial dysfunction by inhibiting calcium overload, collapse of the mitochondrial membrane potential, and opening of the mitochondrial permeability transition pore. And oxidative stress resulting from hypoxia/reoxygenation was ameliorated by saprirearine through the reduction of reactive oxygen species and malondialdehyde as well as activation of superoxide dismutase and catalase. Additionally, saprirearine inactivated cysteinyl aspartate-specific proteinase-3, the up-regulated B-cell lymphoma-2 and down-regulated Bcl-2-associated X protein, to inhibit hypoxia/reoxygenation-induced apoptosis. Further research revealed saprirearine-activated nuclear factor E2-related factor-2 in H9c2 cardiomyocytes, which is closely associated with its protective effects. These findings can provide evidence for the discovery of new therapies targeting myocardial infarction and the application of saprirearine in clinical practice.

Circ_0003204 knockdown protects endothelial cells against oxidized low-density lipoprotein-induced injuries by targeting the miR-491-5p-ICAM1 pathway.

Emerging evidence indicates that circular RNA (circRNA) is implicated in the development of atherosclerosis (AS). This study investigated the effect of circ_0003204 on endothelial cell function and explored the functional mechanism of circ_0003204 in AS progression. AS cell models were constructed by treating human umbilical vein endothelial cells (HUVEC) with oxidized low-density lipoprotein (ox-LDL). The expression of circ_0003204 was detected by quantitative real-time PCR (qPCR). The releases of pro-inflammatory factors were determined by ELISA. Cell viability was checked by CCK-8 assay. Cell apoptosis was monitored by flow cytometry assay. The ability of angiogenesis was assessed by tube formation assay. The protein levels of cell development- and apoptosis-related markers were measured by western blot. The binding relationship between miR-491-5p and circ_0003204 or intercellular adhesion molecule 1 (ICAM1) was verified by dual-luciferase reporter assay or RIP assay. The expression of circ_0003204 was strengthened in ox-LDL-treated HUVECs. Circ_0003204 knockdown inhibited ox-LDL-induced inflammation and cell apoptosis, and promoted ox-LDL-depleted cell viability and tube formation ability in HUVECs. MiR-491-5p was a target of circ_0003204, and miR-491-5p directly bound to ICAM1 3'UTR. Accordingly, circ_0003204 positively regulated ICAM1 expression by targeting miR-491-5p. Rescue experiments presented that miR-491-5p inhibition reversed the effects of circ_0003204 knockdown, and ICAM1 overexpression abolished the effects of miR-491-5p restoration. Circ_0003204 knockdown protects HUVECs against ox-LDL-induced injuries by targeting the miR-491-5p-ICAM1 pathway, hinting that circ_0003204 inhibition might prevent AS development.

An Avascular Niche Created by Axitinib-Loaded PCL/Collagen Nanofibrous Membrane Stabilized Subcutaneous Chondrogenesis of Mesenchymal Stromal Cells.

Engineered cartilage derived from mesenchymal stromal cells (MSCs) always fails to maintain the cartilaginous phenotype in the subcutaneous environment due to the ossification tendency. Vascular invasion is a prerequisite for endochondral ossification during the development of long bone. As an oral antitumor medicine, Inlyta (axitinib) possesses pronounced antiangiogenic activity, owing to the inactivation of the vascular endothelial growth factor (VEGF) signaling pathway. In this study, axitinib-loaded poly(ε-caprolactone) (PCL)/collagen nanofibrous membranes are fabricated by electrospinning for the first time. Rabbit-derived MSCs-engineered cartilage is encapsulated in the axitinib-loaded nanofibrous membrane and subcutaneously implanted into nude mice. The sustained and localized release of axitinib successfully inhibits vascular invasion, stabilizes cartilaginous phenotype, and helps cartilage maturation. RNA sequence further reveals that axitinib creates an avascular, hypoxic, and low immune response niche. Timp1 is remarkably upregulated in this niche, which probably plays a functional role in inhibiting the activity of matrix metalloproteinases and stabilizing the engineered cartilage. This study provides a novel strategy for stable subcutaneous chondrogenesis of mesenchymal stromal cells, which is also suitable for other medical applications, such as arthritis treatment, local treatment of tumors, and regeneration of other avascular tissues (cornea and tendon).

Uniformly-aligned gelatin/polycaprolactone fibers promote proliferation in adipose-derived stem cells and have distinct effects on cardiac cell differentiation.

Cardiac tissue engineering is a promising technique to regenerate cardiac tissue and treat cardiovascular disease. Here we applied a modified method to generate ultrafine uniformly-aligned composite gelatin/polycaprolactone fibers that mimic functional heart tissue. We tested the physical properties of these fibers and analyzed how these composite fibrous scaffolds affected growth and cardiac lineage differentiation in rat adipose-derived stem cells (rADSCs). We found that uniformly aligned composite fiber scaffolds had an anisotropic arrangement, functional mechanical properties, and strong hydrophilicity. The anisotropic scaffolds improved cell attachment, viability, and proliferative capacity of ADSCs over randomly-aligned scaffolds. Furthermore, uniformly aligned composite fiber scaffolds increased the efficiency of cardiomyogenic differentiation, but might reduce the efficiency of cardiac conduction system cell differentiation in ADSCs compared to randomly-oriented scaffolds and tissue culture polystyrene. However, the randomly-oriented composite scaffolds showed no obviously facilitated effects over tissue culture polystyrene on the two cells' differentiation process. The above results indicate that the scaffold fiber alignment has a greater effect on cell differentiation than the composition of the scaffold. Together, the uniformly-aligned composite fibers displayed excellent physical and biocompatible properties, promoted ADSC proliferation, and played distinct roles in the differentiation of cardiomyogenic cells and cardiac conduction system cells from ADSCs. These results provide new insight for the application of anisotropic fibrous scaffolds in cardiac tissue engineering for both in vitro and in vivo research.

Catabolic Activity and Structural Diversity of Bacterial Community in Soil Covered by Halophytic Vegetation.

The catabolic activity and structural diversity of soil bacteria covered by five different halophytic vegetation types in the Yellow River Delta affected by long-term salinization were studied using Biolog-Eco technology. The result showed that soil quality, the diversity, and catabolic activity of the bacterial community of mildly salt-tolerant vegetation (Imperata cylindrical (L.) Beauv. and Apocynum venetum L.) were significantly higher than those of the bacterial community of highly salt-tolerant vegetation (Suaeda salsa (L.) Pall., Aeluropus sinensis (D.) Tzvel.), while these values were lowest for bacterial communities in bare land. The operational taxonomic units (OTUs) and diversity indexes of soil bacteria covered by Aeluropus sinensis were higher than those of soil bacteria covered by other types of vegetation, while those of soil bacteria covered by bare land were lowest. Principal component analysis (PCA) of the carbon source utilization capacity of the soil bacterial communities showed that organic acids, polymers, and amino acids were sensitive carbon sources that enabled study of the diversity of carbon metabolic functions in soil bacterial communities. And redundancy analysis (RDA) showed that D-galacturonic was significantly positively correlated with Verrucomicrobia, which further demonstrated the effect of organic acid carbon sources on metabolic functional diversity of soil bacterial communities in the Yellow River Delta.

Dapagliflozin Attenuates Cardiac Remodeling in Mice Model of Cardiac Pressure Overload.

BACKGROUND: Dapagliflozin (DAPA) is an inhibitor of sodium-glucose cotransporter 2 prescribed for type 2 diabetes mellitus. DAPA plays a protective role against cardiovascular diseases. Nevertheless, the effect and mechanism of DAPA on pressure-overload-induced cardiac remodeling has not been determined. METHODS: We used a transverse aortic constriction (TAC) induced cardiac remodeling model to evaluate the effect of DAPA. Twenty-four C57BL/6J mice were divided into 3 groups: Sham, TAC, and TAC + DAPA groups (n = 8, each). DAPA was administered by gavage (1.0 mg/kg/day) for 4 weeks in the TAC + DAPA group, and then the myocardial hypertrophy, cardiac systolic function, myocardial fibrosis, and cardiomyocyte apoptosis were evaluated. RESULTS: Mice in TAC group showed increased heart weight/body weight, left ventricular (LV) diameter, LV posterior wall thickness, and decreased LV ejection fraction and LV fractional shortening. The collagen volume fraction and perivascular collagen area/luminal area ratio were significantly greater in the TAC group; the TUNEL-positive cell number and PARP level were also increased. We found that DAPA treatment reduced myocardial hypertrophy, myocardial interstitial and perivascular fibrosis, and cardiomyocyte apoptosis. Furthermore, DAPA administration inhibited phosphorylation of P38 and JNK in TAC group. In addition, the inhibited phosphorylation of FoxO1 in the TAC mice was upregulated by DAPA administration. CONCLUSION: DAPA administration had a cardioprotective effect by improving cardiac systolic function, inhibiting myocardial fibrosis and cardiomyocyte apoptosis in a TAC mouse model, indicating that it could serve as a new therapy to prevent pathological cardiac remodeling in nondiabetics.

Differentiation of brown adipose-derived stem cells into cardiomyocyte-like cells is regulated by a combination of low 5-azacytidine concentration and bone morphogenetic protein 4.

Adipose-derived stem cells (ADSCs) could be an ideal candidate for seed cells to regenerate damaged heart tissue. This study examined and compared the cardio-myogenic differentiation efficacy of neonatal rat brown ADSCs (rbADSCs) treated with either 5-azacytidine (5-AZA), bone morphogenetic protein 4 (BMP4), or lower doses of both molecules. Briefly, by investigating the protein expression of cardiac-specific markers (i.e., cardiac troponin-I, α-sarcomeric actinin, sarcoplasmic reticulum Ca2+-ATPase, and connexin 43), our data indicated that rbADSCs could be differentiated into cardiomyocyte-like cells by all three treatments. By quantitatively measuring the number of cells with positive staining for the above markers, we found that the low-dose combined treatment showed higher differentiation efficiency compared to standard dose 5-AZA and BMP4 treatment. Similarly, the expression levels of these proteins as determined by western blotting were higher in the low-dose combination group than in the standard dose 5-AZA and BMP4 groups. Also, the combined strategy maintained the decreased cell viability caused by cytotoxicity of 5-AZA, probably through reducing the ratio of apoptotic rbADSCs. Furthermore, the extracellular regulated protein kinase (ERK) signaling pathways participate in the differentiation process, but the observed effects between the BMP4 and 5-Aza treatments are quite different.