Hint1 Overexpression Inhibits the Cell Cycle and Induces Cell Apoptosis in Human Osteosarcoma Cells.

BACKGROUND: New evidence suggests that histidine triad nucleotide-binding protein 1 (Hint1) exerts a tumor suppressor effect in various human tumors, such as colorectal cancer and gastric cancer. However, it has not been reported whether Hint1 is involved in the occurrence and development of osteosarcoma (OS). MATERIALS AND METHODS: The present study investigated the role of Hint1 in human OS cells by using cell lines, including 143B, U2OS, KHOS-240S, Saos-2 and MG-63. Cell proliferation and apoptosis were detected by flow cytometry. RESULTS: The present result revealed that Hint1 is downregulated in these cell lines. The overexpression of Hint1 by adenovirus transfection in 143B and MG63 cell lines suppressed the proliferation and cell cycle, and increased the cell apoptosis. Mechanically, it was found that Hint1 downregulated the cyclin D1 expression via FOXO1 inhibition. Furthermore, FOXO1 overexpression in the 143B and MG63 cell lines significantly blurred the effects of Hint1 on cellular proliferation and apoptosis. CONCLUSION: The present study indicates that Hint1 inhibits the development of OS by regulating FoxO1-cyclin D1, suggesting that Hint1 may be a new method for the treatment of OS.

CTRP12 Ameliorated Lipopolysaccharide-Induced Cardiomyocyte Injury.

C1q/tumor necrosis factor (TNF)-related protein 12 (CTRP12) is a secretory protein that participates in the regulation of glucose and lipid metabolism in obesity and diabetes. Its role in cardiovascular disease, particularly sepsis-induced cardiac injury, is unclear. Here, we stimulated cardiomyocytes with lipopolysaccharide (LPS) to establish an in vitro cardiomyocyte injury model and CTRP12 was overexpressed with an adenovirus delivery system. Overexpression of CTRP12 reduced the transcription and release of pro-inflammatory cytokines from LPS-stimulated cardiomyocytes, including TNFα, interleukin-1 (IL-1), and IL-6. Reactive oxygen species (ROS) level increased and the oxidation/redox system was disturbed in LPS-stimulated cardiomyocytes, as evident from the decrease in superoxide dismutase activity and an increase in reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and malondialdehyde level. CTRP12 overexpression decreased the increasing level of ROS and ameliorated the unbalance in the oxidation/redox system in LPS-stimulated cardiomyocytes. The viability of cardiomyocytes decreased after LPS stimulation, and the cells underwent apoptosis. CTRP12-overexpressing cardiomyocytes showed a decrease in the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-positive cells, and the ratio of B cell lymphoma (Bcl)-1/Bax in these cells was recovered. In comparison with the control group, LPS-stimulated cardiomyocytes showed reduced expression of nuclear factor E2-related factor 2 (NRF2), while CTRP12-overexpressing cardiomyocytes showed elevated NRF2 expression. Small-interfering RNA-mediated silencing of NRF2 expression in cardiomyocytes resulted in the inhibition of the protective effects of CTRP12. Thus, CTRP12 ameliorated injury in LPS-stimulated cardiomyocytes in an NRF2-dependent manner.

Dihydromyricetin protects against lipopolysaccharide­induced cardiomyocyte injury through the toll­like receptor­4/nuclear factor­κB pathway.

Dihydromyricetin (DHM) is a bioactive flavonoid compound extracted from the stems and leaves of Ampelopsis grossedentata. Previous studies have indicated that DHM has antioxidation and antitumor capabilities, while the effect of DHM on lipopolysaccharide (LPS)­induced cardiomyocyte injury has not been clarified. Therefore, the aim of the present study was to investigate the effect of DHM on LPS­induced cardiomyocyte injury. In the present study, cardiomyocytes were randomized to the control (PBS), LPS and DHM + LPS groups. The LPS group was treated with 10 µg/ml LPS for 12 h and the DHM + LPS group was treated with 100 or 25 µM DHM 12 h prior to treatment with LPS. The protective effect of DHM on LPS­induced cardiomyocytes injury was evaluated by Cell Counting kit­8 assay, TUNEL staining, reverse transcription­quantitative polymerase chain reaction and western blot analysis. The results demonstrated that LPS treatment led to cardiomyocyte apoptosis, and these effects were significantly attenuated by DHM. Furthermore, LPS treatment downregulated the expression of B­cell lymphoma 2 apoptosis regulator (Bcl­2) and induced increased expression of Bcl­2­associated X apoptosis regulator (Bax). Additionally, DHM treatment reversed LPS­induced changes in Bcl­2 expression and Bax expression in cardiomyocytes, and rescued cells from apoptosis. In addition, increased mRNA expression levels of tumor necrosis factor­α and interleukin­6 induced by LPS were attenuated following treatment with DHM. Further investigation demonstrated that DHM suppressed the activation of toll­like receptor­4 (TLR4), which is involved in regulating the downstream signaling pathway of nuclear factor­κB (NF­κB). DHM attenuated LPS­induced cardiomyocyte injury, the potential mechanism responsible for this effect may involve inhibition of TLR4 activation and subsequent regulation of the associated downstream signaling pathway of NF­κB. The current study indicates that DHM may protect cardiomyocytes against LPS­induced injury by inhibition of the TLR4/NF­κB signaling pathway. The results of the present study may provide support for the development DHM as a strategy for the treatment of heart failure in septic shock.

Puerarin attenuates the inflammatory response and apoptosis in LPS-stimulated cardiomyocytes.

Patients with septic shock suffer from high mortality rates, particularly when complicated by severe myocardial depression which is characterized by hypotension and a reduction in cardiac output. Inflammation is an important factor involved in the early stages of sepsis. The aim of the present study was to investigate the effect of the Chinese herbal compound puerarin (1, 5, 10, 20 and 40 µM) on cardiomyocyte inflammatory response in a sepsis model using H9c2 cardiomyocytes stimulated with 1 µg/ml lipopolysaccharide (LPS). The mRNA expression levels of tumor necrosis factor (TNF)-α and interleukin (IL)-ß were evaluated using reverse transcription-quantitative polymerase chain reaction. In addition, the protein expression levels of various factors were determined using western blot analysis. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling was used to evaluate the apoptosis rates in the various groups, and immunocytochemical analysis was employed to determine the effect of puerarin on the nuclear translocation of p65 protein. The present study demonstrated that LPS stimulation increased IL-1ß and TNF-α mRNA expression levels, as compared with the controls (P<0.05). Following treatment with various concentrations of puerarin, the expression levels of IL-1ß and TNF-α were markedly blunted, particularly in the LPS + 40 µM puerarin group (P<0.05 vs. the LPS group). Furthermore, puerarin administration significantly inhibited LPS-induced apoptosis in H9c2 cardiomyocytes, as determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining (TUNEL positive cells: LPS + 40 µM puerarin group, 5.5% vs. LPS group, 10.5%; P<0.01). In addition, puerarin significantly decreased LPS-induced phosphorylated nuclear factor (p-NF)-κB p65 and Bax expression levels, and increased the expression levels of Bcl-2, as compared with the LPS group (P<0.05). These data indicated that puerarin may serve as a valuable protective agent against cardiovascular inflammatory diseases.

Shensongyangxin protects against pressure overload­induced cardiac hypertrophy.

Shensongyangxin (SSYX) is a medicinal herb, which has long been used in traditional Chinese medicine. Various pharmacological activities of SSYX have been identified. However, the role of SSYX in cardiac hypertrophy remains to be fully elucidated. In present study, aortic banding (AB) was performed to induce cardiac hypertrophy in mice. SSYX (520 mg/kg) was administered by daily gavage between 1 and 8 weeks following surgery. The extent of cardiac hypertrophy was then evaluated by pathological and molecular analyses of heart tissue samples. In addition, in vitro experiments were performed to confirm the in vivo results. The data of the present study demonstrated that SSYX prevented the cardiac hypertrophy and fibrosis induced by AB, as assessed by measurements of heart weight and gross heart size, hematoxylin and eosin staining, cross­sectional cardiomyocyte area and the mRNA expression levels of hypertrophic markers. SSYX also inhibited collagen deposition and suppressed the expression of transforming growth factor ß (TGFß), connective tissue growth factor, fibronectin, collagen Ⅰα and collagen Ⅲα, which was mediated by the inhibition of the TGFß/small mothers against decapentaplegic (Smad) signaling pathway. The inhibitory action of SSYX on cardiac hypertrophy was mediated by the inhibition of Akt signaling. In vitro investigations in the rat H9c2 cardiac cells also demonstrated that SSYX attenuated angiotensin II­induced cardiomyocyte hypertrophy. These findings suggested that SSYX attenuated cardiac hypertrophy and fibrosis in the pressure overloaded mouse heart. Therefore, the cardioprotective effect of SSYX is associated with inhibition of the Akt and TGFß/Smad signaling pathways.

Pachymic acid protects H9c2 cardiomyocytes from lipopolysaccharide-induced inflammation and apoptosis by inhibiting the extracellular signal-regulated kinase 1/2 and p38 pathways.

Pachymic acid (PA), a lanostane-type triterpenoid and the major component of Poria cocos alcoholic extracts, has various pharmacological effects, including anti-inflammatory, anti-oxidative and anti-apoptotic. However, few studies have investigated the effects of PA on lipopolysaccharide (LPS)-induced H9c2 cell apoptosis and inflammation, or identified the possible mechanisms underlying these effects. In the present study, H9c2 cardiomyocytes were stimulated by LPS and treated with or without PA. The increased mRNA expression levels of tumor necrosis factor-α, interleukin (IL)-1 and IL-6 induced by LPS were attenuated following treatment with PA. PA also attenuated LPS-induced apoptosis, as determined by a terminal deoxynucleotidyl transferase dUTP nick end labeling assay, and regulated the LPS-induced protein expression levels of caspase 3, 8 and 9. Furthermore, the phosphorylations of extracellular-regulated kinase (Erk)1/2 and p38 in the LPS-treated H9c2 cells were inhibited by PA. These results suggested that treatment with PA prevented the LPS-induced inflammatory and apoptotic response in cardiomyocytes, which may be mediated by inhibition of the Erk1/2 and p38 pathways.

Cathepsin B deficiency attenuates cardiac remodeling in response to pressure overload via TNF-α/ASK1/JNK pathway.

Cathepsin B (CTSB), a member of the lysosomal cathepsin family that is expressed in both murine and human hearts, was previously shown to participate in apoptosis, autophagy, and the progression of certain types of cancers. Recently, CTSB has been linked to myocardial infarction. Given that cathepsin L, another member of the lysosomal cathepsin family, ameliorates pathological cardiac hypertrophy, we hypothesized that CTSB plays a role in pressure overload-induced cardiac remodeling. Here we report that CTSB was upregulated in cardiomyocytes in response to hypertrophic stimuli both in vivo and in vitro. Moreover, knockout of CTSB attenuated pressure overload-induced cardiac hypertrophy, fibrosis, dysfunction, and apoptosis. Furthermore, the aortic banding-induced activation of TNF-α, apoptosis signal-regulating kinase 1 (ASK1), c-Jun NH2-terminal kinases (JNK), c-Jun, and release of cytochrome c was blunted by CTSB deficiency, which was further confirmed in in vitro studies induced by angiotensin II. In cardiomyocytes pretreatment with SP600125, a JNK inhibitor, suppressed the cardiomyocytes hypertrophy by inhibiting the ASK1/JNK pathway. Altogether, these data indicate that the CTSB protein functions as a necessary modulator of hypertrophic response by regulating TNF-α/ASK1/JNK signaling pathway involved in cardiac remodeling.