Ghrelin inhibits myocardial pyroptosis in diabetic cardiomyopathy by regulating ERS and NLRP3 inflammasome crosstalk through the PI3K/AKT pathway.

AIMS: Endoplasmic reticulum stress(ERS) can induce inflammation mediated by NLRP3 inflammatory bodies and link inflammation with oxidative stress in myocardial tissue. Ghrelin is an endogenous growth hormone-releasing peptide that has been proven to have multiple effects, such as regulating energy metabolism and inhibiting inflammation. However, the role of ghrelin in myocardial injury in diabetic rats and the mechanism have not been reported. RESULTS: We found that ghrelin could improve endoplasmic reticulum stress and inflammatory pyroptosis in the myocardial tissue of diabetic rats and reduce ERS and NLRP3 inflammasome crosstalk in H9C2 cardiomyocytes. Interestingly, ghrelin could activate the PI3K/AKT signalling pathway, playing a role in inhibiting endoplasmic reticulum stress and reducing the expression of pyroptosis-related proteins. However, these protective effects could be largely eliminated by LY294002. CONCLUSIONS: In summary, we demonstrated that ghrelin inhibited myocardial pyroptosis in diabetic cardiomyopathy by regulating ERS and NLRP3 inflammasome crosstalk through the PI3K/AKT pathway. Our results provide new insights into the mechanism of diabetic myocardial injury induced by high glucose and high palmitic acid and ghrelin-mediated anti-inflammatory protection and provide potential therapeutic targets and strategies for diabetic cardiomyopathy.

Ghrelin improves lipid metabolism but not glucose metabolism in rats with diabetic cardiomyopathy.Ghrelin improves cardiac dysfunction and structure disorder in diabetic cardiomyopathy.Ghrelin inhibits cardiomyocyte pyroptosis in diabetic cardiomyopathy by regulating myocardial endoplasmic reticulum stress and NLRP3 inflammasome activation.The protective effect mediated by ghrelin may be related to the activation of PI3K/AKT signal pathway.

Diagnostic value of DACT-2 methylation in serum of prostate cancer patients.

BACKGROUND: Currently, prostate cancer (PCa) remains a hard nut to crack for the medical community. Therefore, the identification and development of novel biomarkers that can accurately diagnose disease and predict prognosis are of paramount importance. The objective of this study was to examine the clinical value of DACT-2 promoter methylation in serum of patients with PCa, to discover a potential diagnostic marker for PCa. METHODS: We investigated the methylation status of DACT-2 in the serum of 64 patients with PCa, 22 patients with benign prostatic hyperplasia (BPH), and 47 healthy subjects by methylation-specific PCR (MSP) and real-time methylation-specific PCR (QMSP). Further, we evaluated the relationship between DACT-2 methylation and clinic pathological parameters. Receiver operating characteristic (ROC) curve analysis was applied to assess the sensitivity, specificity, and diagnostic value of DACT-2 methylation and PSA levels. RESULTS: The results of MSP and QMSP showed that the level of methylation of DACT-2 promoter in patients with PCa was significantly higher than that in patients with BPH and healthy subjects. The PCa patients Gleason score and tumor node metastasis (TNM) positively correlated with promoter methylation level of serum DACT-2. The DACT-2 methylation rate was 0.745 with a sensitivity of 81.8%, and a specificity of 75.0%, the sensitivity, and specificity of PSA was 80.1% and 59.4%. ROC curve results displayed that the diagnostic value of DACT-2 is superior to PSA. CONCLUSIONS: Our study confirms that the level of methylation of the DACT-2 promoter in patients with PCa is much higher than that in patients with benign prostatic hyperplasia (BPH) and healthy subjects, suggesting that DACT-2 methylation in serum is a potential biomarker of PCa.

Treadmill Exercise Attenuates Aß-Induced Mitochondrial Dysfunction and Enhances Mitophagy Activity in APP/PS1 Transgenic Mice.

Mitochondrial dysfunction is a hallmark of Alzheimer's disease (AD), which may be related to mitophagy failure. Previous reports suggest that treadmill exercise protects against mitochondrial dysfunction in AD. However, few studies have investigated the relationship between mitophagy and mitochondrial adaptation caused by treadmill exercise in AD. The current study aimed to investigate whether exercise-ameliorated AD is associated with changes in mitophagy activity. Both Wild-type and APP/PS1 transgenic mice were divided into sedentary (WTC and ADC) and exercise (WTE and ADE) groups (n = 9 for each group). WTE and ADE mice were subjected to treadmill exercise for 12 weeks, followed by evaluating the effect of treadmill exercise on learning and memory ability, Aß plaques, mitochondrial Aß peptide level, synaptic activity and mitochondrial function. Meanwhile, mitophagy-related proteins PINK1, Parkin, LC3II and P62 were measured in the hippocampal mitochondrial fractions. The results indicated that exercise not only restored learning and memory ability, but also reduced Aß plaque area, mitochondrial Aß peptide level, and increased levels of synaptic markers SYN and GAP43, as well as reversed mitochondrial dysfunction (defective mitochondrial ultrastructure, decreased PGC-1α, TFAM and ATP levels) in APP/PS1 transgenic mice. Moreover, exercise increased mitophagy activity as evidenced by a significant decrease in levels of P62 and PINK1 as well as an increase in levels of LC3II and Parkin in ADE mice. These findings suggest that treadmill exercise can enhance mitophagy activity in the hippocampus, which is efficient in ameliorating pathological phenotypes of APP/PS1 transgenic mice.

Downregulation of DACT-2 by Promoter Methylation and its Clinicopathological Significance in Prostate Cancer.

Backgrounds: Dapper homolog (DACT) 2, a member of DACT gene family, is frequently down-regulated in various malignancies and linked to tumor progression. However, the regulatory mechanism of DACT-2 expression and its biological role in human prostate cancer (PCa) remains elusive. Here, we investigated the expression and an epigenetic change of DACT-2 in prostate cancer, and determined if these findings were correlated with clinicopathologic characteristics of PCa. Methods: The expression profile of DACT-2 of was detected by qRT-PCR, Western blotting, and immunohistochemistry in four prostate cell lines (RWPE-1, LNCaP, PC-3 and DU145), 56 cases of frozen prostate tissues (forty-seven primary prostate carcinomas, nine paired noncancerous and cancerous prostate tissues) and a tissue microarray sets including 100 paraffin-embedded prostate samples (3 normal tissues, 2 cases of adjacent tissues and 95 cases of cancer). Subsequently, the regulatory mechanism of DACT-2 down-regulation was investigated through methylation-specific PCR (MSP) and bisulfite sequencing (BSP). The role of DACT-2 in prostate cancer cell migration and invasion was respectively examined by wound healing and transwell assay. After 5-aza-2'-deoxycytidine treatment of prostate cancer cells, qRT-PCR was used to detect whether the expression of DACT-2 gene mRNA in the cells recovered. Results: Immunohistochemical results shown that the DACT-2 protein was strongly (3+) expressed in the cytoplasm of all 5 noncancerous tissues and 12.7% (12/95) prostate cancer (PCa) tissues. Whereas 68.4% (65/95) PCa samples and 18.9% (18/95) PCa tissues respectively displayed weakly (1+) expressed and moderately (2+) expressed. In addition, DACT-2 expression was negatively associated with Gleason score in tumor specimens (p=0.029). What's more, down-regulation and promoter methylation of DACT-2 were observed in 68.1% (32/47) frozen PCa tissues and all three prostate cancer cell lines. And, the expression of DACT-2 mRNA was restored by the treatment of demethylated drug 5-aza-2'-deoxycytidine in all prostate cancer lines. Prostate cancer cells invasion and migration were significantly suppressed by ectopic expression of DACT-2 in vitro. Conclusions: Our study provides evidence that DACT-2 may be a useful biomarker for distinguishing prostate tumor tissues from non-cancerous samples and a potential target for epigenetic silencing in primary prostate Cancer.

Effects of treadmill exercise on mitochondrial fusion and fission in the hippocampus of APP/PS1 mice.

Mitochondrial dysfunction is widely recognized as an early event in the pathogenesis of Alzheimer's disease (AD). Defects in mitochondrial fusion and fission have been proposed to lead to learning and memory impairments in AD. The current study aimed to investigate whether exercise-improved learning and memory were associated with improves in mitochondrial function by increased mitochondrial fusion and decreased mitochondrial fission. APP/PS1 transgenic mice were divided into transgenic sedentary (ADC, n = 15) and transgenic exercise (ADE, n = 15) groups. Wild-type mice were also separated into sedentary (WTC, n = 15) and exercise (WTE, n = 15) groups. The WTE and ADE mice were subjected to treadmill exercise for 12 weeks. In this study, learning and memory were significantly decreased in ADC mice compared with those in WTC mice, whereas exercise improved learning and memory in APP/PS1 transgenic mice. Meanwhile, ADC mice displayed defective mitochondrial function as evidenced by a significant increase in swollen mitochondria and vacuoles, loss of mitochondrial cristae, and decreased ATP levels, as well as an imbalance in mitochondrial fusion and fission as evidenced by significantly increased Drp1 and Mff and decreased Mfn1, Mfn2, and Opa1 in the hippocampus. Interestingly, exercise mitigated mitochondrial dysfunction as evidenced by a significant reduction in swollen mitochondria and vacuoles and increased mitochondrial cristae and ATP levels in ADE mice. Coincidentally, exercise promoted the balance of mitochondrial fusion and fission as evidenced by a significantly decreased Drp1 and Mff and increased Mfn1, Mfn2, and Opa1 in the hippocampus. These findings suggest that treadmill exercise efficiently enhances learning and memory in AD by improving mitochondrial dysfunction in APP/PS1 transgenic mice.

Exosomal ephrinA2 derived from serum as a potential biomarker for prostate cancer.

Up-regulation of serum ephrinA2 is common in various malignancies and has been suggested as a potential biomarker for the diagnosis and prognosis of prostate cancer (PCa). However, the type of serum ephrinA2 expressed in PCa patients remains elusive. Furthermore, the level of exosomal ephrinA2 derived from serum is increased in patients with osteoporosis, a common complication of PCa patients undergoing androgen deprivation therapy. It is unknown whether exosomes derived from PCa patient serum contains ephrinA2. In this study, we explored the ephrinA2 expression in whole serum and tissues and identified the circulating exosomal ephrinA2 as a potential biomarker for PCa. Exosomes were isolated from patient sera by differential centrifugation and the presence of ephrinA2 was confirmed via electron microscopy and western blotting. The type of ephrinA2 in serum was evaluated by western blotting. The expression of serum ephrinA2 including secreted and cleaved ephrinA2 and exosomal ephrinA2 were detected by ELISA and western blotting. Compared with benign prostatic hyperplasia (BPH) and controls, the levels of whole serum ephrinA2 and exosomal ephrinA2 were significantly higher in PCa patients. Moreover, exosomal ephrinA2 expression was positively correlated with TNM staging and Gleason score of PCa patients. The diagnostic efficiency of exosomal ephrinA2 was superior to that of whole serum ephrinA2 and serum PSA in distinguishing PCa patients from those from BPH patents. Our study indicates that exosomal ephrinA2 has high potential as a biomarker for the presence of PCa and offers a new therapeutic target for this disease.

Eph/ephrin family anchored on exosome facilitate communications between cells.

Interactions of Ephrins and Eph receptors at cell membranes play crucial role in boundary formation and axon guidance. Extracellular vesicles (EVs), such as exosomes, are formed by cells communicating with each other in paracrine or endocrine manner. Until now, it is thought that direct cell-cell contact is necessary for ephrin and Eph receptor signal transduction. In this review, we discuss recent data that indicate the existence of a novel Eph-ephrin family anchored exosome signaling pathway in long-range intercellular communication and provide evidence that this type of signaling elicits cellular responses in cancer cells, independent of juxtacrine interactions. We emphasize that exosome-anchored Eph/ephrin involves a variety of biological processes and transduction signals, which may serve as a potential diagnostic biomarker.

Ligand-dependent EphA7 signaling inhibits prostate tumor growth and progression.

The downregulation of receptor tyrosine kinase EphA7 is frequent in epithelial cancers and linked to tumor progression. However, the detailed mechanism of EphA7-mediated prostate tumor progression remains elusive. To test the role of EphA7 receptor in prostate cancer (PCa) progression directly, we generated EphA7 receptor variants that were either lacking the cytoplasmic domain or carrying a point mutation that inhibits its phosphorylation by site-directed mutagenesis. Overexpression of wild-type (WT) EphA7 in PCa cells resulted in decreased tumor volume and increased tumor apoptosis in primary tumors. In addition, ectopic expression of WT EphA7 both can delay PCa cell proliferation and could inhibit PCa cell migration and invasion. This protein can also induce PCa cell apoptosis that correlated with increasing the protein expression levels of Bax, elevating the caspase-3 activities, reducing the protein expression levels of Bcl-2 and facilitating the dephosphorylation of Akt, which is further increased by the stimulation of ephrinA5-Fc. However, expression of these EphA7 mutants in PCa cells has no effect in vivo and in vitro. The expression of EphA7 and ephrinA5 was significantly decreased in PCa specimens compared with BPH tissues or paired normal tissues. Moreover, the phosphorylation of EphA7 was positively related with ephrinA5 expression in human prostate tissues. In sum, receptor phosphorylation of EphA7, at least in part, suppress PCa tumor malignancy through targeting PI3K/Akt signaling pathways.

Preparation, activity and structure of cross-linked enzyme aggregates (CLEAs) with nanoparticle.

Cross-linked enzyme aggregates (CLEAs) have emerged as an interesting biocatalyst design for enzyme immobilization. However, the commercialization of CLEAs is often hampered by their shortcomings, such as poor-controlled particle size, low activity and sticky characteristic. In order to overcome these drawbacks, five nanoparticles (NPs) (nano-TiO2, nano-MgO, nano-Ni, nano-Cu and nano-Fe3O4) were used to improve CLEAs activity and structure in this study. Results showed that moderate dosage of nano-TiO2 addition increased CLEAs activity, and the most increment was 15.2% relative to CLEAs without NPs. This was possibly due to more channels and smaller size particle of CLEAs after nano-TiO2 addition. Moreover, nano-TiO2 addition not only decreased fluorescence intensity but also caused the red shift in tryptophan (Trp) and tyrosine (Typ) residues. Nano-TiO2 addition decreased Km and increased Vmax of CLEAs. These changes were benefit to the activity and structure of CLEAs. However, addition of other four NPs (nano-MgO, nano-Ni, nano-Cu and nano-Fe3O4) did not increase CLEAs activity and even decrease CLEAs activity due to less amorphous cavities and larger or discrete particle size than CLEAs without NPs. In addition, FT-IR results showed that NPs addition increases the content of regular structure of CLEAs, and causes a partial transformation of ß-turn into ß-sheet. This study showed that it was potential to improve CLEAs performance by nano-TiO2 addition.

GABARAPL1 suppresses metastasis by counteracting PI3K/Akt pathway in prostate cancer.

Metastasis remains the primary cause of prostate cancer (CaP)-related death. Using a genome wide shRNA screen, we identified GABARAPL1 as a potential CaP metastasis suppressor. GABARAPL1 mRNA levels inversely correlate with the invasive potential of a panel of human CaP cell lines. Lower mRNA levels correlate with higher Gleason scores in clinical CaP tumor samples. Moreover, Kaplan-Meier curves analysis showed that GABARAPL1 down-regulation in cancer tissues is associated with decreased disease-free survival in CaP patients. Knockdown of GABARAPL1 in human LNCaP cells results in increased invasion in vitro and lymph node metastasis in vivo. Vice versa, ectopic expression of GABARAPL1 decreases the invasiveness of CWR22Rv1 cells. Our previous in vitro shRNA screening identified FOXO4, a PI3K/Akt-inactivating downstream target, as a potential CaP metastasis suppressor. We show here that silencing FOXOs leads to reduced GABARAPL1 expression and enhanced invasion in LNCaP cells. Transfection of constitutively-activated Akt (myr-Akt) increased the invasion of LNCaP cells, which is associated with the inactivation of FOXOs and decreased GABARAPL1 expression. Indeed, forced expression of GABARAPL1 reversed the increased invasiveness of LNCaP/myr-Akt cells. Finally, immunohistochemistry analysis shows that Akt phosphorylation is negatively correlated with GABARAPL1 expression in human CaP tissues. Taken together, our data indicate that the suppression of FOXOs-GABARAPL1 signaling by Akt is an important mechanism for CaP progression and metastasis.