Jiayu Diao

This study aimed to evaluate the effect of lncDlx6os1 on high glucose (HG)‐induced oxidative stress and the involvement of the parkin pathway. Methods: Short hairpin RNA of lncDlx6‐os1 (sh‐lncDlx6os1) and small interfering RNA of Parkin (si‐Parkin) were used to inhibit the expression of lncDlx6‐os1 and Parkin in cardiomyocytes, respectively. qRT‐PCR, western blotting, and flow cytometry were performed to investigate the underlying mechanism. Results: sh‐lncDlx6os1 inhibited HG‐induced reactive oxygen species (ROS) generation and increased the expression of HO‐1 and NRF2 in HG‐treated cardiomyocytes. sh‐lncDlx6os1 significantly suppressed the expression of the apoptotic molecule caspase3, and increased the expression of the anti‐apoptotic molecule Bcl‐2, thereby inhibiting HG‐induced apoptosis. Meanwhile, sh‐lncDlx6os1 increased the expression of Sirt1, PINK1, Parkin, and LC3II/LC3I in HG‐treated cardiomyocytes. Suppression of Parkin by si‐Parkin weakened the regulatory effect of sh‐lncDlx6os1 on apoptosis and caspase3 and Bcl‐2 expression. si‐Parkin also attenuated the inhibitory effect of sh‐lncDlx6os1 on ROS generation and increased HO‐1 and NRF2 expressions in HG‐treated cardiomyocytes. Conclusion: Our study revealed that the suppression of lncDlx6os1 significantly alleviated HG‐induced oxidative stress, which was partially mediated by parkin in cardiomyocytes.

Luteolin (LUT) belongs to a kind of flavonoid, which has protective effects on myocardial ischemia/reperfusion (I/R) injury. Sirt3 is located in mitochondria and interacts with Foxo3a to protect mitochondrial function against stress. Mitophagy is an important form of mitochondrial quality control. However, whether LUT regulates mitophagy to alleviate myocardial I/R injury via the Sirt3/Foxo3a pathway is rarely reported. In this study, 3‐(1H‐1,2,3‐triazol‐4‐yl) pyridine (3‐TYP) is used to inhibit the Sirt3/Foxo3a pathway. Male adult rats are divided into four groups: Sham group, I/R group, I/R+LUT group, and I/R+LUT+3‐TYP group. The I/R rats model is established by ligating the left anterior descending coronary artery for 30 min, then releasing the ligature for 24 h. Indexes of left ventricular function, myocardial damage, oxidative stress, and mitophagy are detected. It is found that LUT treatment activated Sirt3/Foxo3a pathway, improves left ventricular function, decreases myocardial infarction size, inhibits myocardial apoptosis and oxidative stress, and initiates mitophagy in I/R rats. Moreover, these protective effects of LUT are weakened when Sirt3 is inhibited. Together, LUT regulates mitophagy to alleviate myocardial I/R injury via the Sirt3/Foxo3a pathway.

Background. Diabetic neuropathic osteoarthropathy (DNOAP) is a rare and easily missed complication for diabetes that leads to increased morbidity and mortality. DNOAP is characterized by progressive destruction of bone and joint, but its pathogenesis remains elusive. We herein aimed to investigate the pathological features and pathogenesis of the cartilages damage in DNOAP patients. Methods. The articular cartilages of eight patients with DNOAP and eight normal controls were included. Masson staining and safranine O/fixed green staining (S‐O) were used to observe the histopathological characteristics of cartilage. The ultrastructure and morphology of chondrocytes were detected by electron microscopy and toluidine blue staining. Chondrocytes were isolated from DNOAP group and control group. The expression of receptor activator of nuclear factor kappaB ligand (RANKL), osteoprotegerin (OPG), interleukin‐1 beta (IL‐1β), interleukin‐6 (IL‐6), tumor necrosis factor‐alpha (TNF‐α), and Aggrecan protein was evaluated by western blot. Reactive oxygen species (ROS) levels were measured using a 2′,7′‐dichlorofluorescin diacetate (DCFH‐DA) probe. The percentage of apoptotic cells was determined by flow cytometry (FCM). The chondrocytes were cultured with different glucose concentrations to observe the expression of RANKL and OPG. Results. Compared with the control group, the DNOAP group showed fewer chondrocytes, subchondral bone hyperplasia, and structural disorder, and a large number of osteoclasts formed in the subchondral bone area. Moreover, mitochondrial and endoplasmic reticulum swellings were observed in the DNOAP chondrocytes. The chromatin was partially broken and concentrated at the edge of nuclear membrane. The ROS fluorescence intensity of chondrocyte in DNOAP group was higher than that in normal control group (28.1 ± 2.3 vs. 11.9 ± 0.7; P < 0.05). The expression of RANKL, TNF‐α, IL‐1β, and IL‐6 protein in DNOAP group was higher than that in normal control group, whereas OPG and Aggrecan protein were lower than that in normal control group (both P < 0.05). FCM showed that the apoptotic rate of chondrocyte in DNOAP group was higher than that in normal control group (P < 0.05). The RANKL/OPG ratio showed significant upward trend when the concentration of glucose was over than 15 mM. Conclusions. DNOAP patients tend to have severe destruction of articular cartilage and collapse of organelle structure including mitochondrion and endoplasm reticulum. Indicators of bone metabolism (RANKL and OPG) and inflammatory cytokines (IL‐1β, IL‐6, and TNF‐α) play an important role in promoting the pathogenesis of DNOAP. The glucose concentration higher than 15 mM made the RANKL/OPG ratio change rapidly.

评估迷迭香酸对高糖培养下心肌细胞线粒体自噬水平以及细胞肥大的影响。 体外培养H9c2大鼠心肌母细胞，分为对照组（葡萄糖5.5 mmol/L）、高糖组（葡萄糖25 mmol/L）、高糖+迷迭香酸组（葡萄糖25 mmol/L+迷迭香酸50 μmol/L）、高糖+迷迭香酸+Parkin-siRNA组（葡萄糖25 mmol/L+迷迭香酸50 μmol/L+Parkin-siRNA转染）；Western blot法测定PINK1、Parkin、LC3II/LC3I蛋白表达水平，透射电子显微镜下观察线粒体自噬体形成情况，流式细胞术检测活性氧物质（ROS）与凋亡水平，分光光度法检测细胞线粒体呼吸链复合酶活性，荧光酶标法检测线粒体膜电位水平，3H-亮氨酸标记法检测细胞蛋白质合成速率，光学显微镜下检测心肌细胞表面积。 迷迭香酸可提高高糖培养下心肌细胞内PINK1、Parkin、LC3-II/LC3-I蛋白表达水平（P < 0.05），增多线粒体自噬体数量，并抑制高糖诱导的ROS生成、恢复线粒体呼吸链复合酶活性与线粒体膜电位水平（P < 0.05），抑制高糖诱导的细胞凋亡（P < 0.05），并降低心肌细胞表面积与蛋白质合成速率（P < 0.05）。利用Parkin-siRNA抑制心肌细胞线粒体自噬，则阻断了迷迭香酸对高糖培养下心肌细胞氧化应激与心肌细胞肥大的保护作用（P < 0.05）。 迷迭香酸可通过激活Parkin介导的线粒体自噬，对高糖诱导心肌细胞的氧化应激损伤有保护作用，并改善心肌细胞肥大。

Atherosclerosis is a severe cardiovascular disease characterized by narrowing of the lumen, plaque formation, and blood flow turbulence as a result of cholesterol and lipid accumulation in the inner lining of arteries. Bishkhapra (Trianthema portulacastrum Linn.) is a well-known common weed belonging to the family Aizoaceae. Several bioactive compounds have been isolated from this weed and widely used against several diseases. The present study evaluated the protective and therapeutic efficacies of T. portulacastrum against atherosclerosis in a rat model. The animals were divided into the sham, control (diabetes- + atherosclerosis-inducing diet), 100 mg/kg T. portulacastrum treatment, 200 mg/kg T. portulacastrum treatment, and positive control groups. Blood glucose, cholesterol, triglyceride, and other lipid parameters, as well as the expression of G-protein-coupled receptor 124 (GPR124), were measured. Glucose, cholesterol, and triglycerides were significantly reduced to near normal levels. The serum levels of fibrinogen, sVCAM-1, and oxidized low density lipoproteins were substantially increased in control rats. Treatment with the T. portulacastrum extract reversed these levels to near normal levels. The mRNA expression of GPR124 was increased by 150% in the control group. However, treatment with T. portulacastrum extract decreased the mRNA expression up to 40% compared with the control group. Rats treated with 100 and 200 mg/kg T. portulacastrum extract showed a decrease in GPR124 protein expression by 9.5% and 33.3%, respectively. Taken together, the results suggest that an extract of T. portulacastrum is effective against atherosclerosis in streptozotocin-induced diabetic rats.

Mitochondrial dysfunction is essential in the development and prognosis of diabetic cardiomyopathy (DCM). Resveratrol (RES) is thought as a mitochondrial protector. In this study, we hypothesized that RES may ameliorate mitochondrial function and consequently improve cardiac function in diabetic rats, and uncoupling protein 2 (UCP2) was involved in the protective effects of RES on DCM. Thirty rats were divided into three groups: normal control, DCM, and DCM+RES groups. DCM was induced by high-fat diet and streptozotocin (STZ) intraperitoneal injection, the rats in DCM+RES group received RES gavage for 16 weeks. RES improved the insulin resistance, and reduced the level of triglyceride, cholesterol, and low density lipoprotein cholesterol (LDLc) in DCM rats (all P < 0.05). Echocardiographic and hemodynamic studies revealed that RES treatment reversed the impaired diastolic and systolic cardiac function in DCM rats. Meanwhile, RES improved myocardial structural disorder and fibrosis, reserved mitochondrial membrane potential level (P < 0.05), and suppressed myocardial apoptosis in DCM rats (P < 0.05). Myocardial mitochondrial respiratory enzyme activities were improved by RES treatment in DCM rats (P < 0.05), accompanied with attenuated reactive oxygen species (ROS) generation (P < 0.05). The expression of UCP2 was further increased by RES treatment both in the myocardium of DCM rats (P < 0.05) and in the H9c2 cardiomyocytes incubated with high-glucose (P < 0.05). The protective effects of RES on high glucose-induced ROS generation, MPTP opening, Cyto c release, and cell apoptosis were all blunted by inhibiting the expression of UCP2 (all P < 0.05). In conclusion, RES treatment improved cardiac function and inhibited cardiomyocyte apoptosis, involving in ameliorating mitochondrial function in diabetic rats. UCP2 mediated the protective effects of RES on diabetic hearts.

To observe the expression of uncoupling protein (UCP2) and its effect on modulation of mitochondrial function and apoptosis of cardiomyocytes exposed to high-glucose. AC16 cardiomyoctyes were randomly divided into normal-glucose group (NG), high-glucose group (HG), HG+ UCP2 siRNA group and HG+ negative control siRNA group.The expression of UCP2, succinodehydrogenase(SDH) activity, ATP content, reactive oxygen species (ROS) generation, cell apoptotic rate, caspase-3 activity and cell viability were detected. Compared with the cardiomyocytes in NG group, the ROS production, apoptotic rate and caspase-3 activity were significantly increased in HG group, accompanying with the decreases in SDH activity, ATP content and cell viability.The expression of UCP2 was increased in HG group. Furthermore, UCP2 siRNA inhibited the expression of UCP2 and aggravated high-glucose induced the ROS production (37.96±1.08 vs 27.68±0.60, P<0.05), cell apoptosis ((25.68±0.78)% vs (17.80±0.99)%, P<0.05), caspase-3 activity ((2.71±0.13)% vs (2.14±0.28)%, P<0.05) and cell inactivation (0.74±0.04 vs 0.62±0.03, P<0.05), but had no impact on SDH activity and ATP content in cardiomyocytes. The up-regulation of UCP2 expression in cardiomyocytes, induced by high-glucose, maybe a protective mechanism for the mitochondrial damage, and UCP2 may inhibit high-glucose induced cardiomyocytes apoptosis.