Sulforaphane reduces lipopolysaccharide-induced inflammation and enhances myogenic differentiation of mouse embryonic myoblasts via the toll-like receptor 4 and NLRP3 pathways.

BACKGROUND: Muscle loss and muscle weakness are manifestations of infection-induced sepsis, a condition that can lead to organ failure and death. Toll-like receptor 4 (TLR4) signaling and the NLRP3 inflammasome are involved in the inflammatory storm and the development of sarcopenia during sepsis. They are also potential targets for sepsis treatment. OBJECTIVES: To explore the effects and molecular mechanisms of sulforaphane (SFN) on sepsis-associated inflammation and sarcopenia. MATERIAL AND METHODS: Mouse C2C12 embryonic myoblasts were treated with lipopolysaccharide (LPS) to simulate sepsis-induced sarcopenia. Molecular mechanisms were investigated using quantitative real-time polymerase chain reaction (qRT-PCR), western blot, immunofluorescence, and enzyme-linked immunosorbent assay (ELISA). RESULTS: Sulforaphane significantly reduced the secretion of the inflammatory cytokine interleukin-1ß (IL-1ß) by C2C12 cells after LPS treatment, and inhibited the production of intracellular reactive oxygen species (ROS). It also increased the expression of E-myosin heavy chain, myosin ID heavy chain, and myogenin, and induced myogenic differentiation of LPS-treated C2C12 cells. Mechanistically, SFN reduced messenger ribonucleic acid and protein levels of TLR4, NLRP3, apoptosis-associated speck-like protein, and Caspase-1 in C2C12 cells, thereby inhibiting the inflammatory response and promoting myogenic differentiation. In addition, the TLR4 inhibitor TAK-242 induced myogenic differentiation in LPS-pretreated C2C12 cells in a similar manner. CONCLUSIONS: Sulforaphane can reduce sepsis-induced inflammatory responses and enhance myogenic differentiation by regulating the TLR4 and NLRP3 inflammasome pathways.

Key circular RNAs identified in male osteoporosis patients by whole transcriptome sequencing.

BACKGROUND: Osteoporosis (OP) is a systemic disease with bone loss and microstructural deterioration. Numerous noncoding RNAs (ncRNAs) have been proved to participate in various diseases, especially circular RNAs (circRNAs). However, the expression profile and mechanisms underlying circRNAs in male osteoporosis have not yet been explored. METHODS: The whole transcriptome expression profile and differences in mRNAs, circRNAs, and microRNAs (miRNAs) were investigated in peripheral blood samples of patients with osteoporosis and healthy controls consisting of males ≥ 60-years-old. RESULTS: A total of 398 circRNAs, 51 miRNAs, and 642 mRNAs were significantly and differentially expressed in osteoporosis compared to healthy controls. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the host genes of significantly differentially expressed circRNAs were mainly enriched in the regulation of cell cycle process: biological process (BP), organelle part cellular components (CC), protein binding molecular function (MF), Toll-like receptor signaling pathway, tumor necrosis factor (TNF) signaling pathway, and thyroid hormone signaling pathway. circRNA-miRNA-mRNA regulatory network was constructed using the differentially expressed RNAs. Moreover, key circRNAs (hsa_circ_0042409) in osteoporosis were discovered and validated by qPCR. CONCLUSIONS: The key cicrRNAs plays a major role in the pathogenesis of osteoporosis and could be used as potential biomarkers or targets in the diagnosis and treatment of osteoporosis.

Overexpression of Dnmt3a ameliorates diabetic muscle atrophy by modulating the Pten/Akt pathway.

NEW FINDINGS: What is the central question of this study? Does Dnmt3a play a crucial role in regulating diabetic muscle atrophy? What is the main finding and its importance? Muscle atrophy is one of the major long-term complications of diabetes mellitus. However, little is known about the molecular mechanism involved. In this paper, we demonstrated that Dnmt3a overexpression effectively improves the diabetic muscle health in mice and documented the underlying mechanisms. DNMT3A might become a promising target to prevent muscle atrophy in patients with diabetes. ABSTRACT: Muscle atrophy is one of the major long-term complications of diabetes mellitus, which greatly affects the mobility of patients. Epigenetic processes mediated by DNA methyltransferases (DNMTs) play crucial roles in the locomotor system, but little is known about the functions of DNMTs in diabetic muscle atrophy. Here, we investigated the function of Dnmt3a in diabetic muscle atrophy and explored the mechanisms involved. Adeno-associated virus AAV2 overexpressing Dnmt3a or its vector control was injected into the tibialis anterior muscle of streptozotocin-induced diabetic mice. Muscle mass and muscle cross-sectional area were used to evaluate muscle atrophy. In vitro, adeno-associated virus AAV2 overexpressing Dnmt3a or its vector control was transfected into C2C12 myoblasts. Horse serum was used to induce differentiation and palmitate to stimulate the C2C12 myoblasts. The expressions of myogenic regulatory factors were examined by real-time PCR and western blot analysis. Overexpression of Dnmt3a attenuated muscle atrophy in diabetic mice and promoted myotube formation of C2C12 myoblasts. Overexpression of Dnmt3a restored the expressions of myogenic regulatory factors atrogin-1, MuRF1, Pax7, Myod1 and myogenin, both in vivo and in vitro. Moreover, overexpression of Dnmt3a activated the phosphorylation of Akt by inhibiting the activation of Pten. This study demonstrates that overexpression of Dnmt3a prevents diabetic muscle atrophy by modulating the Pten/Akt pathway.

Downregulation of miR­16 protects H9c2(2­1) cells against hypoxia/reoxygenation damage by targeting CIAPIN1 and regulating the NF­κB pathway.

The aim of the present study was to determine the function of microRNA­16 (miR­16) in myocardial hypoxia/reoxygenation (H/R)­induced cardiomyocyte injury and the possible mechanism underlying its involvement. An H/R model was constructed using H9c2(2­1) cells in vitro. The results of reverse transcription­quantitative PCR demonstrated that the expression levels of miR­16 were significantly upregulated in H9c2(2­1) cells in the H/R group compared with the sham group (1.53±0.09 vs. 1.0±0.08; P=0.0019). Cell Counting Kit­8 assays revealed that the relative proliferative ability of H9c2(2­1) cells was significantly decreased in the H/R + negative control (NC) group compared with the sham group (0.53±0.05 vs. 1.0±0.08; P=0.00005). Upregulation of miR­16 using miR­16 mimics further decreased the proliferative ability of cells (0.31±0.03 vs. 0.53±0.05; P=0.0097), whereas downregulation of miR­16 using an miR­16 inhibitor increased the proliferative ability of cells compared with the H/R+NC group (0.89±0.08 vs. 0.53±0.05; P=0.000385). Flow cytometric analysis found that the apoptotic rate of H9c2(2­1) cells was increased significantly following H/R compared with the sham group (25.86±2.62% vs. 9.29±0.82%, P=0.000014). Upregulation of miR­16 further increased the apoptotic rate (38.62±2.04% vs. 25.86±2.62%; P=0.000099), whereas downregulation of miR­16 decreased the apoptotic rate compared with the H/R+NC group (15.14±0.92% vs. 25.86±2.62%; P=0.000343). miR­16 directly bound to the 3'­untranslated region of cytokine­induced apoptosis inhibitor 1 (CIAPIN1) and negatively modulated CIAPIN1 expression. Overexpression of CIAPIN1 reversed the changes in the expression of apoptosis­associated proteins caused by H/R. Western blot analysis revealed that the levels of phospho­(p­)nuclear factor­κB (NF­κB) and p­NF­κB inhibitor α (IκBα) were upregulated following H/R (1.82±0.11 vs. 1.0±0.08; P=0.000152; and 1.77±0.07 vs. 1.0±0.00; P=0.000024, respectively), and these changes were further enhanced when miR­16 expression levels were increased (3.10±0.14 vs. 1.82±0.11; P=0.000006; and 2.19±0.10 vs. 1.77±0.07; P=0.0017, respectively). Downregulation of miR­16 exhibited the opposite effect on p­NF­κB and p­IκBα expression levels. The present study illustrates that downregulation of miR­16 may protect against H/R­induced injury partially by targeting CIAPIN1 and the NF­κB signaling pathway.

Exogenous H2S reduces the acetylation levels of mitochondrial respiratory enzymes via regulating the NAD+-SIRT3 pathway in cardiac tissues of db/db mice.

Hydrogen sulfide (H2S), a gaseous molecule, is involved in modulating multiple physiological functions, such as antioxidant, antihypertension, and the production of polysulfide cysteine. H2S may inhibit reactive oxygen species generation and ATP production through modulating respiratory chain enzyme activities; however, the mechanism of this effect remains unclear. In this study, db/db mice, neonatal rat cardiomyocytes, and H9c2 cells treated with high glucose, oleate, and palmitate were used as animal and cellular models of type 2 diabetes. The mitochondrial respiratory rate, respiratory chain complex activities, and ATP production were decreased in db/db mice compared with those in db/db mice treated with exogenous H2S. Liquid chromatography with tandem mass spectrometry analysis showed that the acetylation level of proteins involved in the mitochondrial respiratory chain were increased in the db/db mice hearts compared with those with sodium hydrosulfide (NaHS) treatment. Exogenous H2S restored the ratio of NAD+/NADH, enhanced the expression and activity of sirtuin 3 (SIRT3) and decreased mitochondrial acetylation level in cardiomyocytes under hyperglycemia and hyperlipidemia. As a result of SIRT3 activation, acetylation of the respiratory complexe enzymes NADH dehydrogenase 1 (ND1), ubiquinol cytochrome c reductase core protein 1, and ATP synthase mitochondrial F1 complex assembly factor 1 was reduced, which enhanced the activities of the mitochondrial respiratory chain activity and ATP production. We conclude that exogenous H2S plays a critical role in improving cardiac mitochondrial function in diabetes by upregulating SIRT3.

Identification of Potential Key lncRNAs and Genes Associated with Aging Based on Microarray Data of Adipocytes from Mice.

Objective. This study aimed to screen potential crucial lncRNAs and genes involved in aging. Methods. The data of 9 peripheral white adipocytes, respectively, taken from male C57BL/6J mice (6 months, 14 months, and 18 months of age) in GSE25905 were used in this study. Differentially time series expressed lncRNA genes (DE-lncRNAs) and mRNA genes (DEGs) were identified. After cluster analysis of lncRNAs expression pattern, target genes of DE-lncRNAs were predicted from the DEGs, and functional analysis for target genes was conducted. Results. A total of 8301 time series-related DEGs and 43 time series-related DE-lncRNAs were identified. Among them, 41 DE-lncRNAs targeted 1880 DEGs. The DEGs positively regulated by DE-lncRNAs were mainly related to the development of blood vessel and the pathways of cholesterol biosynthesis and elastic fibre formation. Furthermore, the DEGs negatively regulated by DE-lncRNAs were correlated with protein metabolism. Conclusion. These DE-lncRNAs and DEGs are potentially involved in the process of aging.

Amyloid beta-derived diffusible ligands (ADDLs) induce abnormal expression of insulin receptors in rat hippocampal neurons.

Amyloid beta (Aß) is an important pathogenic factor in Alzheimer's disease (AD). In this study, we investigated the hypothesis that administration of amyloid-derived diffusible ligands (ADDLs) prepared from a synthetic Aß(1-42) amyloid peptide can cause defective expression of insulin receptors (IRs). To this end, primary rat hippocampal neurons were treated with various concentrations of ADDLs and expression levels of IRs were measured using real-time PCR and western blots. In these experiments, the expression of IRs significantly increased following treatment with low concentrations of Aß(1-42). In contrast, when higher concentrations of Aß(1-42) were applied, the number of apoptotic cells present increased, and expression of IRs significantly decreased. In combination, these results suggest that ADDLs is able to induce abnormal expression of IRs and interrupt normal insulin signaling, thereby potentially contributing to central insulin resistance that can occur during progression of AD.

Whole blood viscosity is negatively associated with bone mineral density in postmenopausal women with osteoporosis.

Osteoporosis (OP) is associated with cardiovascular disease. Moreover, osteoporosis has been shown to be an independent predictor of cardiovascular mortality. Recent studies revealed that altered blood rheology plays a critical role in atherosclerosis. A study confirmed that whole blood viscosity (WBV) is a predictor of cardiovascular events. However, little research has been conducted to investigate the relationship between blood viscosity and osteoporosis. In this cross-sectional study, we investigated the relationship between the rheological parameters and bone mineral density (BMD) in 481 subjects in the International Physical Examination and Healthy Center of the Second Affiliated Hospital, Harbin, China. Different biochemical stress and physical activity are correlated to lumbar spine BMD. Stepwise multivariate linear regression analysis revealed that WBV was a significant factor for decreased BMD (ß=-0.513; P<0.001 for lumbar spine L2-4 BMD; ß=-0.157; P=0.003 for femoral neck BMD). In conclusion, The findings show that WBV is elevated in osteoporosis and negatively correlated with BMD. Further studies are warranted to investigate whether antiosteoporosis medication could normalize whole blood viscosity in postmenopausal women with osteoporosis.

[Study of the correlation about IGF-I receptor and ß-amyloid in Alzheimer's disease].

OBJECTIVE: To detect the expression of IGF-I receptor in the hippocampus neuron of rat treated by Aß(1-42), and thus from the receptor level explore the disorder of central nervous insulin signaling and the possible molecular mechanism of Alzheimer disease. METHODS: Cultured primary hippocampus neurons were treated with different concentrations of Aß(1-42), apoptosis rate was detected by flow cytometry, real-time quantitative PCR and Western blot were used to detect IGF-I receptor expression. RESULTS: Primary cultured cells mature in 7(th) days; after detected by flow cytometry, early apoptosis rate in Aß(1-42) 0, 30, 60, 100 µmol/L groups showed a concentration-dependent increase. PCR results showed that, in 30 (1.72 ± 0.33) and 60 µmol/L (1.86 ± 0.36) treatment groups levels of the IGF-I receptor gene were significantly higher than the control group (regarded as 1) (P < 0.01), 100 µmol/L group (0.70 ± 0.15) was significantly lower than the control group (P < 0.05). Results of Western blot showed 30 and 60 µmol/L protein level of the treatment groups are 1.08 ± 0.04, 1.74 ± 0.08 (P < 0.01) and 100 µmol/L group was 0.79 ± 0.11(P < 0.05), which had same trend with PCR. CONCLUSIONS: Aß(1-42) induced altered expression of IGF-I receptors in rat hippocampus cells, maybe one of the molecule mechanisms of Alzheimer disease.

Post-conditioning protects cardiomyocytes from apoptosis via PKC(epsilon)-interacting with calcium-sensing receptors to inhibit endo(sarco)plasmic reticulum-mitochondria crosstalk.

The intracellular Ca(2+) concentration ([Ca(2+)](i)) is increased during cardiac ischemia/reperfusion injury (IRI), leading to endo(sarco)plasmic reticulum (ER) stress. Persistent ER stress, such as with the accumulation of [Ca(2+)](i), results in apoptosis. Ischemic post-conditioning (PC) can protect cardiomyocytes from IRI by reducing the [Ca(2+)](i) via protein kinase C (PKC). The calcium-sensing receptor (CaR), a G protein-coupled receptor, causes the production of inositol phosphate (IP(3)) to increase the release of intracellular Ca(2+) from the ER. This process can be negatively regulated by PKC through the phosphorylation of Thr-888 of the CaR. This study tested the hypothesis that PC prevents cardiomyocyte apoptosis by reducing the [Ca(2+)](i) through an interaction of PKC with CaR to alleviate [Ca(2+)](ER) depletion and [Ca(2+)](m) elevation by the ER-mitochondrial associated membrane (MAM). Cardiomyocytes were post-conditioned after 3 h of ischemia by three cycles of 5 min of reperfusion and 5 min of re-ischemia before 6 h of reperfusion. During PC, PKC(epsilon) translocated to the cell membrane and interacted with CaR. While PC led to a significant decrease in [Ca(2+)](i), the [Ca(2+)](ER) was not reduced and [Ca(2+)](m) was not increased in the PC and GdCl(3)-PC groups. Furthermore, there was no evident psi(m) collapse during PC compared with ischemia/reperfusion (I/R) or PKC inhibitor groups, as evaluated by laser confocal scanning microscopy. The apoptotic rates detected by TUNEL and Hoechst33342 were lower in PC and GdCl(3)-PC groups than those in I/R and PKC inhibitor groups. Apoptotic proteins, including m-calpain, BAP31, and caspase-12, were significantly increased in the I/R and PKC inhibitor groups. These results suggested that PKC(epsilon) interacting with CaR protected post-conditioned cardiomyocytes from programmed cell death by inhibiting disruption of the mitochondria by the ER as well as preventing calcium-induced signaling of the apoptotic pathway.

[Abnormal expression of insulin receptor induced by Aß(1-42) in rat hippocampus neuron].

OBJECTIVE: To detect the expression change of insulin receptor under the induction of Aß(1-42) in rat hippocampus neuron and thus from the receptor level explore the disorder of central nervous insulin signaling and molecular mechanism of Alzheimer's disease. METHODS: Cultured primary hippocampus neuron was treated with different concentrations of Aß(1-42). Apoptosis was detected by flow cytometry. And real-time quantitative PCR (polymerase chain reaction) and Western blot were used to detect the expression of insulin receptor. RESULTS: Primary cultured cells, mature at Day 7, were identified as hippocampal cells. After the treatment with different concentrations of Aß(1-42) (0 - 150 µmol/L), the ≥ 30 µmol/L treatment groups had greater early apoptosis rates (32.4%, 36.1%, 51.0%, 53.6%) than that in the control group (13.4%) in a concentration-dependent fashion. The PCR results showed that the levels of insulin receptor gene were significantly higher in 30 (2.56 ± 0.19) and 60 µmol/L (3.44 ± 0.23) treatment groups than that the control group (regarded as 1) (P < 0.01) while the 100µmol/L group (0.74 ± 0.15) was significantly lower than the control group (P < 0.01). And the results of Western blot had the same trend with those of PCR. The 30 and 60 µmol/L protein level of the treatment groups were 1.27 ± 0.13, 1.82 ± 0.10 (P < 0.01) and 100µmol/L group was 0.82 ± 0.08 (P < 0.05). CONCLUSIONS: Aß(1-42) induces an altered expression of insulin receptors in rat hippocampus cells and results in its functional defects. It may cause insulin resistance in center nervous system.

Human thioredoxin exerts cardioprotective effect and attenuates reperfusion injury in rats partially via inhibiting apoptosis.

BACKGROUND: Thioredoxin is one of the most important redox regulating proteins. Although thioredoxin has been shown to protect cells against different kinds of oxidative stress, the role of thioredoxin in myocardial ischemia and reperfusion injury has not been fully understood. This study was conducted to explore the protective role of human thioredoxin on myocardial ischemia and reperfusion injury and its potential mechanisms. METHODS: Purified human thioredoxin was injected into adult Wistar rats, which were subjected to 30 minutes of myocardial ischemia followed by 2 or 24 hours of reperfusion. We detected 1) the infarct size; 2) the level of malondisldehyde (MDA) in serum; 3) the expression of caspase-9, and cytochrome c in/out of mitochondria by Western blotting; 4) apoptosis by terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) assay and caspase-3 and its protein by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting; 5) the expression of bcl-2 and bax in cardium by immunohistochemical (IHC) assay. RESULTS: Human thioredoxin reduced myocardial ischemia/reperfusion injury as evidenced by significant decrease of myocardial infarct size (P < 0.01), notable reduction of myocyte apoptosis (P < 0.01), lower systemic oxidative stress level (P < 0.01) after reperfusion for 2 hours, and few inflammatory cell infiltration after reperfusion for 24 hours in rats. Furthermore, treatment with human thioredoxin significantly reduced the release of mitochondrial cytochrome C (P < 0.05), and inhibited the activity of caspase-9 (P < 0.05) and caspase-3 (P < 0.01 in mRNA and P < 0.05 at protein level). Meanwhile, human thioredoxin markedly increased bcl-2 expression (P < 0.05). CONCLUSIONS: These results strongly suggest that human thioredoxin has cardioprotective effects on myocardial ischemia/reperfusion and its anti-apoptotic role may be mediated by modulating bcl-2 and the mitochondria-dependent apoptotic signaling pathway.

[Phosphorylation of PKCdelta participates in the toxicity of 6-hydroxydopamine on dopaminergic neuroblastoma cell].

OBJECTIVE: To investigate the role of phosphorylation of protein kinase C (PKC) delta in the toxicity of 6-hydroxydopamine (6-OHDA) to the death of dopaminergic neurons. METHODS: Human neuroblastoma cells of the line SH-SY5Y were cultured 6-OHDA of the concentrations of 0, 50, 100, 200, and 400 micromol/L was added to observe its toxicity. Rottlerin (PKCdelta inhibitor, 2 micromol/L), bisindolylmaleimide (Bis, general PKC inhibitor, 10 nmol/L), Gö6976 (calcium-dependent PKC inhibitor, 5 nmol/L), and phobol-12-myristate-13-acetate (PMA, PKC activator, 100 nmol/L) were added into the culture fluid of another SH-SY5Y cells respectively, and then (1) culture fluid of equal volume was added for 18 h so as to observe there effects on the survival of the SH-SY5Y cells, or (2) 100 micromol/L 6-OHDA was added to observe the effects of intervention on PKC on the survival of the SH-SY5Y cells by using MTT assay. Cell lysis solution with phosphatase inhibitor was used to lyse the culture cells to extract plasma protein. Western blotting was used to detect the expression of phosphorylated PKCdelta. RESULTS: MTT assay showed that all different concentrations (50 - 400 micromol/L) of 6-OHDA significantly and dose-dependently caused cell death with an EC50 of 92 micromol/L. Pretreatment with rottlerin and Bis alone did not influence the survival of the cells significantly,. However, the survival rate of the cells pretreated by Gö6976 alone was 92.3% +/- 3.2% that of the control group (P < 0.01), and the survival rate of the cells pretreated by PMA was 49.5% +/- 1.0% that of the control group (P < 0.01) Pretreatment of rottlerin decreased the death rate of the cells treated with 6-OHDA to 30.4% +/- 1.6% and conferred significant protection against 6-OHDA neurotoxicity by 57% +/- 6% compared to that of the cells treated by 6-OHDA alone (P < 0.01). However, Bis and Gö6976 did not affect the 6-OHDA-induced cell damage. Pretreatment of PMA increased the death rate of the cells treated with 6-OHDA to 67.1% +/- 2.2% and significantly aggravated 6-OHDA-induced cell toxicity by 66% +/- 9% (P < 0.01). Western blotting showed that 6-OHDA administration increased the expression of phosphorylated PKCdelta, pretreatment with Rottlerin inhibited such increase, PMA promoted such increase, and Bis and Gö6976 did not influence such increase. CONCLUSION: Inhibition of PKCdelta phosphorylation with rottlerin ameliorates the neurotoxicity evoked by 6-OHDA, and activation of PKCdelta phosphorylation by PMA aggravates neurotoxicity, which implicating that this kinase participates in the 6-OHDA-induced neurotoxicity and Parkinsonian neurodegeneration.