Hypoxic Preconditioning Enhances Biological Function of Endothelial Progenitor Cells via Notch-Jagged1 Signaling Pathway.

BACKGROUND Hypoxic preconditioning may be a key influence on functions of endothelial progenitor cells (EPCs). MATERIAL AND METHODS To investigate the role and mechanism of the Notch-Jagged1 pathway on endothelial progenitor cells in hypoxic preconditioning, endothelial progenitor cells were randomly allocated into 5 groups: 1 Normoxic control group; 2 Hypoxic blank group; 3 Hypoxic+25 µM DAPT group; 4 Hypoxic+50 µM DAPT group; 5 Hypoxic+100 µM DAPT group. After reoxygenation, protein and mRNA levels of Jagged1 were measured by Western blot and quantitative RT-PCR. The MTT test was used to assess proliferation. ELISA was used to measure NO and VEGF secretion. RESULTS Hypoxic preconditioning treatment significantly upregulated both protein and mRNA levels of Jagged1 in endothelial progenitor cells. It also enhanced proliferation ability and elevated secretion of NO and VEGF. Furthermore, after blocking the Notch pathway by using DAPT, Jagged1 expression and EP proliferation, migration, and secretion of NO and VEGF were decreased in a dose-dependent manner. CONCLUSIONS Our results suggest the Notch-Jagged1 pathway enhances EPCs proliferation and secretion ability during hypoxic preconditioning.

Redd1 knockdown prevents doxorubicin-induced cardiac senescence.

Regulated in development and DNA damage response-1 (Redd1) is a stress-response gene that is transcriptionally induced by diverse stressful stimuli to influence cellular growth and survival. Although evidence suggests that aging may drive Redd1 expression in skeletal muscles, the expression patterns and functions of Redd1 in senescent cardiomyocytes remain unspecified. To address this issue, in vitro and in vivo models of cardiomyocyte senescence were established by administration of doxorubicin (Dox). Redd1 overexpression and knockdown was achieved in cultured H9c2 cardiomyocytes and mouse tissues using, respectively, lentivirals and adeno-associated virus 9 (AAV9) vectors. In the hearts of both aged (24 months old) and Dox-treated mice, as well as in Dox-exposed H9c2 cardiomyocytes, high Redd1 expression accompanied the increase in both cellular senescence markers (p16INK4a and p21) and pro-inflammatory cytokine expression indicative of a stress-associated secretory phenotype (SASP). Notably, Redd1 overexpression accentuated, whereas Redd1 silencing markedly attenuated, Dox-induced cardiomyocyte senescence features both in vitro and in vivo. Notably, AAV9-shRNA-mediated Redd1 silencing significantly alleviated Dox-induced cardiac dysfunction. Moreover, through pharmacological inhibition, immunofluorescence, and western blotting, signaling pathway analyses indicated that Redd1 promotes cardiomyocyte senescence as a downstream effector of p38 MAPK to promote NF-kB signaling via p65 phosphorylation and nuclear translocation.

Honokiol antagonizes doxorubicin­induced cardiomyocyte senescence by inhibiting TXNIP­mediated NLRP3 inflammasome activation.

Senescence of cardiomyocytes is considered a key factor for the occurrence of doxorubicin (Dox)­associated cardiomyopathy. The NOD­like receptor family pyrin domain­containing 3 (NLRP3) inflammasome is reported to be involved in the process of cellular senescence. Furthermore, thioredoxin­interactive protein (TXNIP) is required for NLRP3 inflammasome activation and is considered to be a key component in the regulation of the pathogenesis of senescence. Studies have demonstrated that pretreatment with honokiol (Hnk) can alleviate Dox­induced cardiotoxicity. However, the impact of Hnk on cardiomyocyte senescence elicited by Dox and the underlying mechanisms remain unclear. The present study demonstrated that Hnk was able to prevent Dox­induced senescence of H9c2 cardiomyocytes, indicated by decreased senescence­associated ß­galactosidase (SA­ß­gal) staining, as well as decreased expression of p16INK4A and p21. Hnk also inhibited TXNIP expression and NLRP3 inflammasome activation in Dox­stimulated H9c2 cardiomyocytes. When TXNIP expression was enforced by adenovirus­mediated gene overexpression, the NLRP3 inflammasome was activated, which led to inhibition of the anti­inflammation and anti­senescence effects of Hnk on H9c2 cardiomyocytes under Dox treatment. Furthermore, adenovirus­mediated TXNIP­silencing inhibited the NLRP3 inflammasome. Consistently, TXNIP knockdown enhanced the anti­inflammation and anti­senescence effects of Hnk on H9c2 cardiomyocytes under Dox stimulation. In summary, Hnk was found to be effective in protecting cardiomyocytes against Dox­stimulated senescence. This protective effect was mediated via the inhibition of TXNIP expression and the subsequent suppression of the NLRP3 inflammasome. These results demonstrated that Hnk may be of value as a cardioprotective drug by inhibiting cardiomyocyte senescence.

Redd1 protects against post­infarction cardiac dysfunction by targeting apoptosis and autophagy.

Post­infarction remodeling is accompanied and influenced by perturbations in the mammalian target of rapamycin (mTOR) signaling. Regulated in development and DNA damage response­1 (Redd1) has been reported to be involved in DNA repair and modulation of mTOR activity. However, little is known about the role of Redd1 in the heart. In the present study the potential contribution of Redd1 overexpression to the chronic phase of heart failure after myocardial infarction (MI) was explored and the mechanisms underlying Redd1 actions were determined. Redd1 was downregulated in the mouse heart subjected to MI surgery. To determine the role of Redd1 in the process of MI, adeno­associated virus 9 mediated overexpression of Redd1 was used to enhance Redd1 content in cardiomyocytes. Redd1 overexpression improved left ventricular dysfunction and reduced the expansion index. Additionally, Redd1 overexpression resulted in suppressed myocardial apoptosis and improved autophagy. Furthermore, the studies revealed that Redd1 overexpression could inhibit the phosphorylation of mTOR and its downstream effectors P70/S6 kinase and 4EBP1. In conclusion, this study demonstrated that Redd1 overexpression protects against the development and persistence of heart failure post MI by reducing apoptosis and enhancing autophagy via the mTOR signaling pathway. The present study clearly demonstrated that Redd1 is a therapeutic target in the development of heart failure after MI.

Reduced NRF2 expression suppresses endothelial progenitor cell function and induces senescence during aging.

Aging is associated with an increased risk of cardiovascular disease. Numerical and functional declines in endothelial progenitor cells (EPCs) limit their capacity for endothelial repair and promote the development of cardiovascular disease. We explored the effects of nuclear factor (erythroid-derived 2)-like 2 (NRF2) on EPC activity during aging. Both in vitro and in vivo, the biological functioning of EPCs decreased with aging. The expression of NRF2 and its target genes (Ho-1, Nqo-1 and Trx) also declined with aging, while Nod-like receptor protein 3 (NLRP3) expression increased. Aging was associated with oxidative stress, as evidenced by increased reactive oxygen species and malondialdehyde levels and reduced superoxide dismutase activity. Nrf2 silencing impaired the functioning of EPCs and induced oxidative stress in EPCs from young mice. On the other hand, NRF2 activation in EPCs from aged mice protected these cells against oxidative stress, ameliorated their biological dysfunction and downregulated the NLRP3 inflammasome. These findings suggest NRF2 can prevent the functional damage of EPCs and downregulate the NLRP3 inflammasome through NF-κB signaling.

Nrf2 protects against diabetic dysfunction of endothelial progenitor cells via regulating cell senescence.

Diabetes is associated with an increased risk of cardiovascular disease. A decrease in the number and functionality of endothelial progenitor cells (EPCs) leads to reduced endothelial repair and the development of cardiovascular disease. The aim of the present study was to explore the effect and underlying mechanisms of nuclear factor erythroid 2­related factor 2 (Nrf2) on EPC dysfunction caused by diabetic mellitus. The biological functions of EPCs in streptozotocin­induced diabetic mice were evaluated, including migration, proliferation, angiogenesis and the secretion of vascular endothelial growth factor (VEGF), stromal­derived growth factor (SDF) and nitric oxide (NO). Oxidative stress levels in diabetic EPCs were also assessed by detecting intracellular reactive oxygen species (ROS), superoxide dismutase (SOD) and malondialdehyde (MDA). EPC senescence was evaluated by measuring p16 and b­gal expression and observing the senescence­associated secretory phenotype. In addition, the function of EPCs and level of oxidative stress were assessed following Nrf2 silencing or activation. Nrf2 silencing resulted in a decrease of EPC biological functions, accelerated cell senescence and increased oxidative stress, as indicated by ROS and MDA upregulation accompanied with decreased SOD activity. Furthermore, Nrf2 silencing inhibited migration, proliferation and secretion in EPCs, while it increased oxidative stress and cell senescence. Nrf2 activation protected diabetic EPCs against the effects of oxidative stress and cell senescence, ameliorating the biological dysfunction of EPCs derived from mice with diabetes. In conclusion, Nrf2 overexpression protected against oxidative stress­induced functional damage in EPCs derived from diabetic mice by regulating cell senescence.

[Protective effect of purariae isoflavone on apoptosis cells of nasal mocosas in ovariectomized rats].

OBJECTIVE: To study the protective effect of purariae isoflavone on apoptosis cells of atrophic nasal mucosas in ovariectomized rats. METHOD: 60 rats were divided into four groups as control, ovariectomized, ovariectomized + nylestriol (O + N) and ovariectomized + purariae isoflavone (O + P), each with 15 rats. Earlier apotosis cells of mucosas taken from nasal septum were measured with flow cytometry. RESULT: Compared with control group, and the number of apoptosis cells of mucosas increased after being ovariectomized,and the number of apoptosis cells of mucosas in O + N and O + D group didn't change. CONCLUSION: Nylestriol and purariae isoflavone might have effects on protecting cells of mucosas from lacking of estrogen by decreasing apoptosis cells in ovariectomized rats.

[Effect of the purariae-isofiavones on estrogen level in normal and ovariectomized rats].

OBJECTIVE: To study the effect of purariae isoflavone on estrogen level in ovariectomized rats. METHOD: 80 rats were divided into four groups randomly, every group with 20 rats: 1. Control group; 2. Normal + purariae isoflavone group; 3. Ovariectomized group; 4. Ovariectomized + purariae isoflavone group. Estrogen level and gonadotropin-releasing hormone level of all rats were measured. RESULT: Thirty days after being ovariectomized, E2, E3 level was significantly lower than that of the first group(P < 0.05). But Testerone, FSH, LH, PRL and GH increased(P < 0.05). After being gastrogavaged with purariae-isolfavone for thirty days, Estrogen level and gonadotropin-relasing hormone level of the second group were significantly lower in various degree than those of normal control group (P < 0.05). But in ovariectomized rats, the estrogen level was recovered (P > 0.05). The gonadotropin-releasing hormone level was increased (P < 0.05). CONCLUSION: Purariae-isoflavone can increase estrogen level to normal in ovariectomized rats by way of increasing the level of gonadotropin-releasing hormone. In normal rats, it has anti-estrogen effect.

[The ocular optic fiber used in the endoscopic sinus surgery of dacryocystorhinostomy in the treatment of chronic dacryocystitis and recurrent dacryocystitis].

OBJECTIVE: To explore a method for locating the area of lacrimal sac in dacryocystorhinostomy under endoscopy. METHOD: Sixty-eight patients were performed dacryocystorhinostomy under endoscopy. Take light spot of ocular optic fiber as the lacrimal sac projection to the lateral wall of the nasal cavity position. RESULT: With the guiding of ocular optic fiber, lacrimal sac can be located accurately. The operating time of dacryocystorhinostomy under endoscopy was shortened significantly, and the operation procedure was simplified. All patients were followed up for 2 years, only 2 recurrent cases were found. The success rate reach to 97.06% (66/68). CONCLUSION: Ocular optical fiber used in locating the lacrimal sac in dacryocystorhinostomy under endoscopy is simple and feasible, and can be widely used.

[Surgery of nasopharyngeal angiofibroma].

OBJECTIVE: To study the operations of nasopharyngeal angiofibroma. METHOD: Twenty-two patients with nasopharyngeal angiofibroma operated by various operative approaches were studied in this research. All their clinic data were collected and analyzed. RESULT: In the operation, the brooding amount was from 400 ml to 1600 ml. One case was recurred in half a year after operation. The other 21 cases didn't recur after one to two years follow-up. CONCLUSION: In order to improve the treatment, reduce the recurrence of tumor and decrease brooding in operation, better preparation before surgery, reasonable surgical route,external carotid artery delegation, embolization under digital subtraction angiography(DSA) and resecting the all tumor as possible in the operation are very important

[Protective effect of estrogens replacement on apoptosis cells of nasal mocosas in ovariectomized rats].

OBJECTIVE: To study the protective effect of nylestriol on apoptosis cells of atrophic nasal mucosas in ovariectomized rats and the difference between nasal drip and gastrogavage. METHOD: Sixty rats with atrophic rhinitis were divided into four groups at random (each with 15 rats): contrary group (Cg), ovariectomized group (Og), ovariectomized + nylestriol nasal drip group (ONNDg), and ovariectomized + nylestriol by gastrogavage (ONGg). Earlier apoptosis cells of nasal mucosas taken from nasal septum were measured with flow cytometry. RESULT: After being ovariectomized, the number of apoptosis cells of mucosas increased. In ONGg, the number of apoptosis cells of mucosas increased at 15 d after operation (P < 0.05), but it recovered at 30 d and 60 d after operation. In ONGg, the number of apoptosis cells of mucosas increased at 15 d and 30 d after operation (P < 0.05), but it recovered at 60 d after operation. CONCLUSION: Estrogen replacement by gastrogavage and via nasal drip have effects on protecting cells of mucosas from lacking of estrogen by decreasing apoptosis cells in ovariectomized rats. It might cost more time to get therapeutic effectiveness via nasal drip than by gastrogavage.

[Protective effect of daizein on apoptosis cells of nasal mucosas in ovariectomized rats].

OBJECTIVE: To study the protective effect of daizein on apoptosis cells of atrophic nasal mucosas in ovariectomized rats. METHODS: Sixty rats were divided into four groups as contrary, ovariectomized, ovariectomized + nylestriol (O + N) and ovariectomized + daizein (O + D), each with 15 rats. Earlier apotosis cells of nasal mucosas taken from nasal septum were measured with flow cytometry. RESULTS: Compared with contrary group, the number of apoptosis cells of mucosas increased after being ovariectomized, the number of apoptosis cells of mucosas in O + N and O + D groups didn't change. CONCLUSION: Estrogen replacement and daizein might have effects on protecting cells of mucosas from lacking of estrogen by decreasing apoptosis cells in ovariectomized rats.

[Distribution of calcitonin gene-related peptide in guinea pig cochlea].

OBJECTIVE: To observe the distribution of CGRP in guinea pig cochlea. METHOD: CGRP was labeled by immunostaning technique. Distribution of CGRP immunoreactivity was observed with light microscopy. RESULT: CGRP immunoreactivity was located in SGN, nerve fibers at osseous spiral lamina, stria vascularis, IHC, adjacent area of OHC and Deiters' cells. CONCLUSION: CGRP distributes extensively in guinea pig cochlea. CGRP may play an important role as neurotransmitter and/or neuromodulator to hearing function by modulating HC, supporting cells, SGN and other neurons along the process of auditory nerve. It may have effect on on cochlear blood flow, too.