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Smoking is identified as a risk factor for periodontitis. Carbon monoxide (CO)-releasing molecule-3 (CORM-3) is a compound that has demonstrated anti-inflammatory effects in vitro and in vivo studies. The present study aimed to investigate the effects of CORM-3 on the expression of inflammatory and osteoclastogenic cytokines in human periodontal ligament cells (PDLCs) stimulated by nicotine and lipopolysaccharide (LPS). The cells were pretreated with CORM-3 and then cultured in medium in the presence of nicotine and LPS. The mRNA and protein expression levels of prostaglandin E2 (PGE2), cyclooxygenase-2 (COX‑2), osteoprotegerin (OPG), receptor activator of nuclear factor-κB ligand (RANKL) and heme oxygenase-1 (HO-1) were evaluated using reverse transcription-quantitative polymerase chain reaction and western blot analysis. The mRNA and protein expression levels of these cytokines were also evaluated in PDLCs transiently transfected with HO-1 small interfering RNA (siRNA) in response to nicotine and LPS stimulation. CORM-3 attenuated the LPS- and nicotine-induced production of PGE2, COX-2 and RANKL in human PDLCs by releasing CO, and upregulated the expression of OPG. However, these effects of CORM-3 were abrogated when HO-1 siRNA was transiently transfected into the cells. These results demonstrate that CORM-3 exerts anti-inflammatory and anti-osteoclastogenic effects on nicotine- and LPS-stimulated human PDLCs via the HO-1 pathway, which suggests its promising potential for use in the treatment of inflammatory periodontal disease.

Histone deacetylase (HDAC) inhibitors have been widely shown to result in cancer cell death. The present study investigated the mechanisms underlying the antitumor effects of the phytochemical trichostatin A (TSA), a classic pan-HDAC inhibitor, in 5,637 urinary bladder cancer cells. It was found that TSA caused cell cycle arrest at the G2/M and G1 phase accompanied by reduced expression of cyclin D1 and upregulated induction of p21. In addition, TSA induced morphological changes, reduced cell viability and apoptotic cell death in 5,637 cells through caspase-3 activation followed by PARP cleavage. The loss of mitochondrial membrane potential (MMP) indicated that TSA induced apoptosis in 5,637 cells through the intrinsic mitochondrial pathway. TSA significantly suppressed Akt activity at 12 h after treatment, suggesting that the apoptosis in the early phase was mediated by Akt inhibition. In addition, the protein level of transcription factor Sp1 was decreased at 24 h after TSA treatment, which likely led to the downregulation of survivin gene expression, and then contributed to the antitumor activity of TSA. Taken together, the present study delineated that TSA-induced growth inhibition and apoptosis in 5,637 cells was associated with pAKT inhibition and MMP loss at the early phase, followed by downregulation of Sp1 and survivin at the late phase of treatment.

The present study was performed to investigate the role of p38 mitogen‑activated protein kinase (MAPK) in the resorption of herniated intervertebral discs in 30 rats. In the non‑contained and p38 MAPK inhibition (p38i) groups, two coccygeal intervertebral discs (IVDs) were removed and wounded prior to relocation into the subcutaneous space of the skin of the back. In the contained group, the cartilage endplates maintained their integrity. Furthermore, SB203580 was injected intraperitoneally into the p38i group, whereas saline was injected into the other two groups. In the non‑contained group, the weight of the relocated IVDs decreased to a greater extent over time when compared with the contained and p38i groups. Phosphorylated p38, tumor necrosis factor‑α, and interleukin‑1β were observed to exhibit higher expression levels in the non‑contained group compared with the contained and p38i groups, at weeks 1 and 4 post‑surgery. The expression level of caspase‑3 and the densities of apoptotic disc cells were significantly higher in the non‑contained group compared with the contained and p38i groups at 4 weeks post‑surgery. In conclusion, p38 MAPK induces apoptosis in IVDs, while also accelerating the resorption of the relocated IVDs. Thus, p38 MAPK may be important in spontaneous resorption of IVDs.

Hydrogen sulfide (H(2)S) has recently been identified as an endogenous gaseous signaling molecule. In the vascular system, the formation of H(2)S is catalyzed by cystathionine γ‑lyase (CSE). Previous studies have demonstrated the protective effects of H(2)S on ischemic injury in various types of tissue. However,, little is known about the role of H(2)S in diabetes-associated vascular diseases. Thus, the aim of the present study was to examine the possible role of H(2)S in high glucose-induced vascular dysfunction, and to explore the underlying mechanisms. Human umbilical vein endothelial cells (HUVECs) were isolated from human umbilical veins. The levels of H(2)S following treatment with various levels of glucose were determined and the secretion of endothelin-1 (ET-1) was measured by ELISA. The mRNA and protein expression of CSE in the HUVECs was determined by real-time RT-PCR and western blot analysis, respectively. Treatment with high glucose (25 mmol/l) for 48 h significantly increased the secretion of ET-1 by HUVECs, with the concomitant suppression of H(2)S production and CSE protein expression. The increase in exogenous H(2)S levels through the administration of sodium hydrosulfide (NaHS) attenuated the high glucose-induced downregulation of CSE protein expression, and significantly inhibited the secretion of ET-1. These results suggest that the downregulation of CSE protein expression and the subsequent decrease in H(2)S production play a role in high glucose-induced vascular dysfunction possibly by increasing the secretion of ET-1 by endothelial cells.

The p38 pathway, which is important in mitogen-activated protein kinase (MAPK) family protein signaling, leads to mitochondrial dysfunction and activation of caspase-3. B-cell lymphoma 2 (Bcl‑2) family members are involved in the regulation of activities associated with the survival and death of neurons through apoptosis and have important functions in most types of apoptosis. In the present study, the effects of the p38 MAPK inhibitor SB203580 on N-methyl-d-aspartate (NMDA)-induced cerebral cortical neuron apoptosis were observed to further analyze the possible mechanisms of NMDA-induced neuronal death. Cultured primary cortical neurons were randomly divided into five groups: A control group, NMDA group and three SB203580 interventional groups. The lactate dehydrogenase (LDH) and MTT assays were employed to investigate the effects of the drugs on apoptosis. The morphology of apoptotic cells was observed using acridine orange/ethidium bromide (AO/EB) fluorescence staining. The expression levels of phospho‑(p)‑p38MAPK, Bcl‑2 and Bcl-2-associated X (Bax) were assessed by immunohistochemical methods and western blot analysis to investigate the possible underlying protective mechanisms. The cell viability markedly decreased following incubation with NMDA. The protein levels of cell death repressor Bcl-2 and the levels of Bcl-2/Bax were downregulated. The protein levels of p‑p38MAPK and cell death promoter Bax increased significantly in cells with NMDA treatment. However, these changes were inhibited by SB203580 treatment, particularly in the high‑dose group. Neuronal death induced by NMDA in primary cortical neurons was caused in part by apoptosis, which was mediated through the activation of the p38 signaling pathway by NMDA. SB203580 has neuroprotective effects against NMDA‑induced apoptosis.

Indirubin is the active component of Dang Gui Long Hui Wan, a traditional Chinese herbal medicine used as therapy for chronic myelogenous leukemia (CML). In clinical studies, indirubin seldom caused major side-effects. However, the functional effect of indirubin on acute lymphoblastic leukemia (ALL) is unclear. Therefore, we investigated the effects of indi- rubin-3'-monoxime (I3M) on the ALL cell line JM1 and the CML cell line K562 (control). The anti-leukemia effects and mechanisms of I3M were similar on ALL and CML cells. I3M significantly and dose-dependently decreased cell viability. The G2/M cell cycle phase was arrested and the sub-G1 propor- tion was relatively increased. In addition, caspase-3 activation led to poly(ADP-ribose) polymerase (PARP)-1 cleavage and the progression of apoptosis. Notably, I3M induced autophagy. However, I3M had no effect on necrosis in either cell line. We specifically found that I3M only marginally affected the survival of primary mature lymphocytes, and was not cytotoxic to granulocytes. Since I3M induced apoptosis and autophagy in human lymphocytic leukemia cells and caused few side-effects in healthy lymphocytes and granulocytes, I3M may be useful for clinical anti-ALL therapy.

Glucose-regulated protein 75 (Grp75), also known as mortalin/mthsp70/PBP74, is a member of the heat-shock protein 70 (HSP70) family. Grp75 is known to protect cells from stress-induced injury. Previous studies have shown that the expression of Grp75 is upregulated by a low dose of ionizing radiation (IR). To evaluate the protective role of Grp75 on cell proliferation in response to IR, Grp75 was overexpressed in a rat adrenal pheochromocytoma cell line (PC12). It was revealed that Grp75 overexpression desensitized PC12 cells to IR-mediated cell injury. In addition, the expression of topoisomerase IIα (Topo IIα) was downregulated in PC12 cells following γ-ray IR. The effect of Grp75 overexpression on Topo IIα expression was examined. It was revealed that Grp75 overexpression reversed the inhibitory effect of IR on Topo IIα expression. In conclusion, the data indicated that Grp75 overexpression attenuates IR-induced injury in PC12 cells by maintaining the expression of Topo IIα.