Roles of oxidative stress/JNK/ERK signals in paraquat-triggered hepatic apoptosis.

Paraquat (PQ), a toxic and nonselective bipyridyl herbicide, is one of the most extensively used pesticides in agricultural countries. In addition to pneumotoxicity, the liver is an important target organ for PQ poisoning in humans. However, the mechanism of PQ in hepatotoxicity remains unclear. In this study, we found that exposure of rat hepatic H4IIE cells to PQ (0.1-2 mM) induced significant cytotoxicity and apoptosis, which was accompanied by mitochondria-dependent apoptotic signals, including loss of mitochondrial membrane potential (MMP), cytosolic cytochrome c release, and changes in the Bcl-2/Bax mRNA ratio. Moreover, PQ (0.5 mM) exposure markedly induced JNK and ERK1/2 activation, but not p38-MAPK. Blockade of JNK and ERK1/2 signaling by pretreatment with the specific pharmacological inhibitors SP600125 and PD98059, respectively, effectively prevented PQ-induced cytotoxicity, mitochondrial dysfunction, and apoptotic events. Additionally, PQ exposure stimulated significant oxidative stress-related signals, including reactive oxygen species (ROS) generation and intracellular glutathione (GSH) depletion, which could be reversed by the antioxidant N-Acetylcysteine (NAC). Buffering the oxidative stress response with NAC also effectively abrogated PQ-induced hepatotoxicity, MMP loss, apoptosis, and phosphorylation of JNK and ERK1/2 protein, however, the JNK or ERK inhibitors did not suppress ROS generation in PQ-treated cells. Collectively, these results demonstrate that PQ exposure induces hepatic cell toxicity and death via an oxidative stress-dependent JNK/ERK activation-mediated downstream mitochondria-regulated apoptotic pathway.

One-stage reconstruction of extensive exposed tibia on malnourished patient using single-layer Integra and amino acid supplements: A case report and literature review.

RATIONALE: Extremity injuries resulting from motor vehicle collisions, especially those leading to bone-exposed wounds, present challenges for achieving effective wound coverage. Such injuries are susceptible to complications including infections, osteomyelitis, and unexpected amputations due to inadequate blood supply. Severe traumatic degloving injuries often entail damage to the surrounding blood vessels, making local or free flaps impractical choices in many cases. Consequently, treatment options may vary based on distinct clinical scenarios, with no standardized guidelines available. Our study introduces an integrated approach utilizing dermal substitutes and skin grafts as a safer treatment modality for managing large-area tibial exposure resulting from traffic accidents. PATIENT CONCERNS: A 66-year-old male with a compromised nutritional status was struck by a car while riding a motorcycle. Previous attempts using double-layer Integra and negative pressure wound therapy (NPWT) for two-stage reconstruction have been unsuccessful. DIAGNOSES: Computed tomography imaging studies revealed multiple comminuted and displaced fractures involving the left femoral shaft, left proximal tibia, left patella, and proximal fibula, as well as a fracture of the right fibular shaft and an avulsion fracture of the right distal medial femur. The patient's condition corresponded to Type 3B in the Gustilo classification for open fractures, and the patient had an Injury Severity Score of 25. INTERVENTIONS: We applied a one-stage reconstruction involving single-layer Integra, split-thickness skin grafts, NPWT, and nutritional supplements containing various amino acids. OUTCOMES: By implementing an integrated treatment approach and providing diligent wound care over a total of 2 months, the patient achieved successful healing and expressed satisfaction with the postoperative results. LESSONS: This study offers insights into the effectiveness of employing one-stage reconstruction for traumatic injuries with extensive exposed tibias. In addition, it underscores the impact of a patient's nutritional status on wound healing and introduces a potential solution for similar challenging cases.

Healing of a bone-exposed soft tissue defect after surgical correction of traumatic patellar dislocation: A case report.

RATIONALE: Reconstructive surgery is widely considered the primary treatment for soft tissue defects around the knee owing to its high flexibility. However, in our recent case study, we explored an alternative approach using decellularized collagen dressings, which proved highly effective in healing a soft tissue defect involving bone exposure following surgical correction of a traumatic patellar dislocation. PATIENT CONCERNS: A 65-year-old male with a traumatic patellar dislocation in the lower extremity failed to approximate the wound after surgical correction. The patient refused additional surgical reconstruction because of the potential risks of multiple operative complications. DIAGNOSES: Traumatic patellar dislocation complicated by exposed bone following surgical treatment was made. INTERVENTIONS: The procedure was performed using ABCcolla® Collagen Matrix (ACRO Biomedical, Taiwan), an acellular dermal matrix made from a decellularized native porcine collagen scaffold dressing. Collagen dressings were applied to the soft tissue defect, and biointegration was observed in the wound area of bone exposure. OUTCOMES: Through the application of ABCcolla® Collagen Matrix (ACRO Biomedical, Taiwan) and diligent wound care for a total of 105 days, the patient healed successfully and achieved partial functional recovery after undergoing rehabilitation. During recent outpatient clinic visits, the patient is now able to ambulate independently with the aid of crutches. LESSONS: Collagen dressings circumvent the potential risks and complications associated with multiple surgical procedures. We believe that the utilization of collagen dressings, combined with careful wound management, could serve as a promising alternative treatment option for patients with soft tissue defects around the knee in the future.

Unawareness of hepatitis B infection and lack of surveillance are associated with severity of hepatocellular carcinoma.

Unawareness of hepatitis B virus (HBV) infection and lack of surveillance may serve as major barriers to HBV control and contributors to severe hepatocellular carcinoma (HCC) at presentation. This study evaluated the risk of HBV unawareness and its relationship with HCC severity. This retrospective study was conducted in a tertiary hospital in Taiwan. Patients with HBV-related HCC diagnosed from 2011 to 2021 were enrolled. The demographic, clinical, and HCC characteristics were collected and compared between patients with HBV unawareness and awareness with and without surveillance. Of 501 HBV-related HCC patients enrolled, 105 (21%) patients were unaware of HBV infection at the time of HCC diagnosis. Patients with HBV unawareness were significantly younger and had poorer liver function than those with HBV awareness. Patients with HBV unawareness also had a significantly higher rate of detectable HBV DNA and an advanced stage of HCC. Ninety-one (23%) of the HBV-aware patients did not receive regular surveillance. Patients with HBV unawareness and awareness without surveillance shared similar clinical characteristics with more severe HCC status. Further regression analysis demonstrated that HBV awareness with periodic surveillance was associated with early stage HCC. Meanwhile, we observed that there was no change in the proportion of HBV awareness over the past 10 years. Patients with surveillance also had better HCC survival than patients without surveillance or unawareness. HBV unawareness and lack of regular surveillance correlated with advanced HCC at presentation. Efforts to improve HBV education, disease awareness, and HCC surveillance are needed.

Rat Bait, Not Healthy Rice!

Bromadiolone, a potent, long-acting anticoagulant rodenticide is frequently tinted to a red or pink color and mixed with cereals as rat bait. Six peoples working in a small factory suffered from a severe bleeding tendency several weeks after consuming a rice meal that was tainted with bromadiolone mistaken to be healthy food. High serum levels of bromadiolone and excessive bleeding were found in these individuals, and they needed vitamin K1 therapy for weeks. These cases indicated that long-acting anticoagulant rodenticide might induce cumulative toxicity in repeated, low-dose exposure, and the blood levels of bromadiolone might be an indicator for antidote therapy if available.

Chlorpyrifos induces neuronal cell death via both oxidative stress and Akt activation downstream-regulated CHOP-triggered apoptotic pathways.

Chlorpyrifos (CPF) is one of the most abundant and widely used organophosphate pesticides for agricultural, industrial, and household purposes in the world. Epidemiological studies have reported that CPF can induce neurotoxic impairments in mammalian, which is linked to an important risk factor for development of neurodegenerative diseases (NDs). However, limited information is available on CPF-induced neurotoxicity, with the underlying exact mechanism remains unclear. In this study, CPF exposure (10-400 µM) significantly reduced Neuro-2a cell viability and induced apoptotic events, including the increase in caspase-3 activity, apoptotic cell population, and cleavage of caspase-3/-7 and PARP. Exposure of Neuro-2a cells to CPF also triggered CHOP activation. Transfection with CHOP-specific siRNA markedly suppressed the expression of CHOP, and attenuated cytotoxicity and apoptotic events in CPF-exposed Neuro-2a cells. Furthermore, CPF exposure obviously evoked the phosphorylation of Akt as well as ROS generation in a time-dependent manner. Pretreatment with LY294002 (an Akt inhibitor) effectively attenuated the CPF-induced Akt phosphorylation, CHOP activation, and apoptotic events, but not that ROS production. Of note, buffering the ROS generation with antioxidant N-acetylcysteine effectively prevented the CPF-induced ROS generation, CHOP activation, and apoptotic events, but not that the Akt phosphorylation. Collectively, these findings indicate that CPF exposure exerts neuronal cytotoxicity via the independent pathways of ROS generation and Akt activation downstream-regulated CHOP-triggered apoptosis, ultimately leading to neuronal cell death.

Involvement of AMPKα and MAPK-ERK/-JNK Signals in Docetaxel-Induced Human Tongue Squamous Cell Carcinoma Cell Apoptosis.

Cancers of the oral cavity can develop in the anatomic area extending from the lip, gum, tongue, mouth, and to the palate. Histologically, about 85-90% of oral cavity cancers are of the type squamous cells carcinomas (SCCs). The incidence of oral tongue SCC is higher in the tongue than any other anatomic area of the oral cavity. Here, we investigated the therapeutic effects and molecular mechanisms of docetaxel, which is a paclitaxel antitumor agent, on the cell growth of a human tongue SCC-derived SAS cell line. The results showed that docetaxel (10-300 nM) induced cytotoxicity and caspase-3 activity in SAS cells. Moreover, docetaxel (100 nM) promoted the expression of apoptosis-related signaling molecules, including the cleavages of caspase-3, caspase-7, and poly (ADP-ribose) polymerase (PARP). In mitochondria, docetaxel (100 nM) decreased the mitochondrial membrane potential (MMP) and Bcl-2 mRNA and protein expression and increased cytosolic cytochrome c protein expression and Bax mRNA and protein expression. In terms of mitogen-activated protein kinase (MAPK) and adenosine monophosphate-activated protein kinase (AMPK) signaling, docetaxel increased the expression of phosphorylated (p)-extracellular signal-regulated kinase (ERK), p-c-Jun N-terminal kinase (JNK), and p-AMPKα protein expression but not p-p38 protein expression. Moreover, the increase in caspase-3/-7 activity and Bax protein expression and decreased Bcl-2 protein expression and MMP depolarization observed in docetaxel-treated SAS cells could be reversed by treatment with either SP600125 (a JNK inhibitor), PD98059 (an MEK1/2 (mitogen-activated protein kinase kinase 1/2) inhibitor), or compound c (an AMPK inhibitor). The docetaxel-induced increases in p-JNK, p-ERK, and p-AMPKα protein expression could also be reversed by treatment with either SP600125, PD98059, or compound c. These results indicate that docetaxel induces human tongue SCC cell apoptosis via interdependent MAPK-JNK, MAPK-ERK1/2, and AMPKα signaling pathways. Our results show that docetaxel could possibly exert a potent pharmacological effect on human oral tongue SCC cell growth.

Norketamine, the Main Metabolite of Ketamine, Induces Mitochondria-Dependent and ER Stress-Triggered Apoptotic Death in Urothelial Cells via a Ca2+-Regulated ERK1/2-Activating Pathway.

Ketamine-associated cystitis is characterized by suburothelial inflammation and urothelial cell death. Norketamine (NK), the main metabolite of ketamine, is abundant in urine following ketamine exposure. NK has been speculated to exert toxic effects in urothelial cells, similarly to ketamine. However, the molecular mechanisms contributing to NK-induced urothelial cytotoxicity are almost unclear. Here, we aimed to investigate the toxic effects of NK and the potential mechanisms underlying NK-induced urothelial cell injury. In this study, NK exposure significantly reduced cell viability and induced apoptosis in human urinary bladder epithelial-derived RT4 cells that NK (0.01-0.5 mM) exhibited greater cytotoxicity than ketamine (0.1-3 mM). Signals of mitochondrial dysfunction, including mitochondrial membrane potential (MMP) loss and cytosolic cytochrome c release, were found to be involved in NK-induced cell apoptosis and death. NK exposure of cells also triggered the expression of endoplasmic reticulum (ER) stress-related proteins including GRP78, CHOP, XBP-1, ATF-4 and -6, caspase-12, PERK, eIF-2α, and IRE-1. Pretreatment with 4-phenylbutyric acid (an ER stress inhibitor) markedly prevented the expression of ER stress-related proteins and apoptotic events in NK-exposed cells. Additionally, NK exposure significantly activated JNK, ERK1/2, and p38 signaling and increased intracellular calcium concentrations ([Ca2+]i). Pretreatment of cells with both PD98059 (an ERK1/2 inhibitor) and BAPTA/AM (a cell-permeable Ca2+ chelator), but not SP600125 (a JNK inhibitor) and SB203580 (a p38 inhibitor), effectively suppressed NK-induced mitochondrial dysfunction, ER stress-related signals, and apoptotic events. The elevation of [Ca2+]i in NK-exposed cells could be obviously inhibited by BAPTA/AM, but not PD98059. Taken together, these findings suggest that NK exposure exerts urothelial cytotoxicity via a [Ca2+]i-regulated ERK1/2 activation, which is involved in downstream mediation of the mitochondria-dependent and ER stress-triggered apoptotic pathway, consequently resulting in urothelial cell death. Our findings suggest that regulating [Ca2+]i/ERK signaling pathways may be a promising strategy for treatment of NK-induced urothelial cystitis.

Methylmercury Induces Mitochondria- and Endoplasmic Reticulum Stress-Dependent Pancreatic ß-Cell Apoptosis via an Oxidative Stress-Mediated JNK Signaling Pathway.

Methylmercury (MeHg), a long-lasting organic pollutant, is known to induce cytotoxic effects in mammalian cells. Epidemiological studies have suggested that environmental exposure to MeHg is linked to the development of diabetes mellitus (DM). The exact molecular mechanism of MeHg-induced pancreatic ß-cell cytotoxicity is still unclear. Here, we found that MeHg (1-4 µM) significantly decreased insulin secretion and cell viability in pancreatic ß-cell-derived RIN-m5F cells. A concomitant elevation of mitochondrial-dependent apoptotic events was observed, including decreased mitochondrial membrane potential and increased proapoptotic (Bax, Bak, p53)/antiapoptotic (Bcl-2) mRNA ratio, cytochrome c release, annexin V-Cy3 binding, caspase-3 activity, and caspase-3/-7/-9 activation. Exposure of RIN-m5F cells to MeHg (2 µM) also induced protein expression of endoplasmic reticulum (ER) stress-related signaling molecules, including C/EBP homologous protein (CHOP), X-box binding protein (XBP-1), and caspase-12. Pretreatment with 4-phenylbutyric acid (4-PBA; an ER stress inhibitor) and specific siRNAs for CHOP and XBP-1 significantly inhibited their expression and caspase-3/-12 activation in MeHg-exposed RIN-mF cells. MeHg could also evoke c-Jun N-terminal kinase (JNK) activation and reactive oxygen species (ROS) generation. Antioxidant N-acetylcysteine (NAC; 1mM) or 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox; 100 µM) markedly prevented MeH-induced ROS generation and decreased cell viability in RIN-m5F cells. Furthermore, pretreatment of cells with SP600125 (JNK inhibitor; 10 µM) or NAC (1 mM) or transfection with JNK-specific siRNA obviously attenuated the MeHg-induced JNK phosphorylation, CHOP and XBP-1 protein expression, apoptotic events, and insulin secretion dysfunction. NAC significantly inhibited MeHg-activated JNK signaling, but SP600125 could not effectively reduce MeHg-induced ROS generation. Collectively, these findings demonstrate that the induction of ROS-activated JNK signaling is a crucial mechanism underlying MeHg-induced mitochondria- and ER stress-dependent apoptosis, ultimately leading to ß-cell death.

Quercetin induces tongue squamous cell carcinoma cell apoptosis via the JNK activation-regulated ERK/GSK-3α/ß-mediated mitochondria-dependent apoptotic signaling pathway.

Tongue squamous cell carcinoma (SCC) is a most common type of oral cancer. Due to its highly invasive nature and poor survival rate, the development of effective pharmacological therapeutic agents is urgently required. Quercetin (3,3',4',5,7-pentahydroxyflavone) is a polyphenolic flavonoid found in plants and is an active component of Chinese herbal medicine. The present study investigated the pharmacological effects and possible mechanisms of quercetin on apoptosis of the tongue SCC-derived SAS cell line. Following treatment with quercetin, cell viability was assessed via the MTT assay. Apoptotic and necrotic cells, mitochondrial transmembrane potential and caspase-3/7 activity were analyzed via flow cytometric analyses. A caspase-3 activity assay kit was used to detect the expression of caspase-3 activity. Western blot analysis was performed to examine the expression levels of proteins associated with the MAPKs, AMPKα, GSK3-α/ß and caspase-related signaling pathways. The results revealed that quercetin induced morphological alterations and decreased the viability of SAS cells. Quercetin also increased apoptosis-related Annexin V-FITC fluorescence and caspase-3 activity, and induced mitochondria-dependent apoptotic signals, including a decrease in mitochondrial transmembrane potential and Bcl-2 protein expression, and an increase in cytosolic cytochrome c, Bax, Bak, cleaved caspase-3, cleaved caspase-7 and cleaved poly (ADP-ribose) polymerase protein expression. Furthermore, quercetin significantly increased the protein expression levels of phosphorylated (p)-ERK, p-JNK1/2 and p-GSK3-α/ß, but not p-p38 or p-AMPKα in SAS cells. Pretreatment with the pharmacological JNK inhibitor SP600125 effectively reduced the quercetin-induced apoptosis-related signals, as well as p-ERK1/2 and p-GSK3-α/ß protein expression. Both ERK1/2 and GSK3-α/ß inhibitors, PD98059 and LiCl, respectively, could significantly prevent the quercetin-induced phosphorylation of ERK1/2 and GSK3-α/ß, but not JNK activation. Taken together, these results suggested that quercetin may induce tongue SCC cell apoptosis via the JNK-activation-regulated ERK1/2 and GSK3-α/ß-mediated mitochondria-dependent apoptotic signaling pathway.

Arsenic induces autophagy-dependent apoptosis via Akt inactivation and AMPK activation signaling pathways leading to neuronal cell death.

Inorganic arsenic (As3+), a well-known worldwide industrial and environmental pollutant, has been linked to neurodegenerative disorders (NDs). Autophagy plays an important role in controlling neuronal cell survival/death. However, limited information is available regarding the toxicological mechanism at the interplay between autophagy and As3+-induced neurotoxicity. The present study found that As3+ exposure induced a concomitant activation of apoptosis and autophagy in Neuro-2a cells, which was accompanied with the increase of phosphatidylserine exposure on outer membrane leaflets and apoptotic cell population, and the activation of caspase-3, -7, and PARP as well as the elevation of protein expressions of LC3-II, Atg-5, and Beclin-1, and the accumulation of autophagosome. Pretreatment of cells with autophagy inhibitor 3-MA, but not that of Z-VAD-FMK (a pan-caspase inhibitor), effectively prevented the As3+-induced autophagic and apoptotic responses, indicating that As3+-triggered autophagy was contributing to neuronal cell apoptosis. Furthermore, As3+ exposure evoked the dephosphorylation of Akt. Pretreatment with SC79, an Akt activator, could significantly attenuated As3+-induced Akt inactivation as well as autophagic and apoptotic events. Expectedly, inhibition of Akt signaling with LY294002 obviously enhanced As3+-triggered autophagy and apoptosis. Exposure to As3+ also dramatically increased the phosphorylation level of AMPKα. Pretreatment of AMPK inhibitor (Compound C) could markedly abrogate the As3+-induced phosphorylated AMPKα expression, and autophagy and apoptosis activation. Taken together, these results indicated that As3+ exerted its cytotoxicity in neuronal cells via the Akt inactivation/AMPK activation downstream-regulated autophagy-dependent apoptosis pathways, which ultimately lead to cell death. Our findings suggest that the regulation of Akt/AMPK signals may be a promising intervention to against As3+-induced neurotoxicity and NDs.

4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene, a Major Active Metabolite of Bisphenol A, Triggers Pancreatic ß-Cell Death via a JNK/AMPKα Activation-Regulated Endoplasmic Reticulum Stress-Mediated Apoptotic Pathway.

4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), a major active metabolite of bisphenol A (BPA), is generated in the mammalian liver. Some studies have suggested that MBP exerts greater toxicity than BPA. However, the mechanism underlying MBP-induced pancreatic ß-cell cytotoxicity remains largely unclear. This study demonstrated the cytotoxicity of MBP in pancreatic ß-cells and elucidated the cellular mechanism involved in MBP-induced ß-cell death. Our results showed that MBP exposure significantly reduced cell viability, caused insulin secretion dysfunction, and induced apoptotic events including increased caspase-3 activity and the expression of active forms of caspase-3/-7/-9 and PARP protein. In addition, MBP triggered endoplasmic reticulum (ER) stress, as indicated by the upregulation of GRP 78, CHOP, and cleaved caspase-12 proteins. Pretreatment with 4-phenylbutyric acid (4-PBA; a pharmacological inhibitor of ER stress) markedly reversed MBP-induced ER stress and apoptosis-related signals. Furthermore, exposure to MBP significantly induced the protein phosphorylation of JNK and AMP-activated protein kinase (AMPK)α. Pretreatment of ß-cells with pharmacological inhibitors for JNK (SP600125) and AMPK (compound C), respectively, effectively abrogated the MBP-induced apoptosis-related signals. Both JNK and AMPK inhibitors also suppressed the MBP-induced activation of JNK and AMPKα and of each other. In conclusion, these findings suggest that MBP exposure exerts cytotoxicity on ß-cells via the interdependent activation of JNK and AMPKα, which regulates the downstream apoptotic signaling pathway.

Roles of ERK/Akt signals in mitochondria-dependent and endoplasmic reticulum stress-triggered neuronal cell apoptosis induced by 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene, a major active metabolite of bisphenol A.

Bisphenol A (BPA) is recognized as a harmful pollutant in the worldwide. Growing studies have reported that BPA can cause adverse effects and diseases in human, and link to a potential risk factor for development of neurodegenerative diseases (NDs). 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), which generated in the mammalian liver after BPA exposure, is a major active metabolite of BPA. MBP has been suggested to exert greater toxicity than BPA. However, the molecular mechanism of MBP on the neuronal cytotoxicity remains unclear. In this study, MBP exposure significantly reduced Neuro-2a cell viability and induced apoptotic events that MBP (5-15 µM) exhibited greater neuronal cytotoxicity than BPA (50-100 µM). The mitochondria-dependent apoptotic signals including the decrease in mitochondrial membrane potential (MMP) and the increase in cytosolic apoptosis-induced factor (AIF), cytochrome c release, and Bax protein expression were involved in MBP (10 µM)-induced Neuro-2a cell death. Exposure of Neuro-2a cells to MBP (10 µM) also triggered endoplasmic reticulum (ER) stress through the induction of several key molecules including glucose-regulated protein (GRP)78, C/EBP homologous protein (CHOP), X-box binding protein (XBP)-1, protein kinase R-like ER kinase (PERK), eukaryotic initiation factor 2α (eIF2α), inositol-requiring enzyme(IRE)-1, activation transcription factor(AFT)4 and ATF6, and caspase-12. Pretreatment with 4-PBA (an ER stress inhibitor) and specific siRNAs for GRP78, CHOP, and XBP-1 significantly suppressed the expression of these ER stress-related proteins and the activation of caspase-12/-3/-7 in MBP-exposed Neuro-2a cells. Furthermore, MBP (10 µM) exposure dramatically increased the activation of extracellular regulated protein (ERK)1/2 and decreased Akt phosphorylation. Pretreatment with PD98059 (an ERK1/2 inhibitor) and transfection with the overexpression of activation of Akt1 (myr-Akt1) effectively suppressed MBP-induced apoptotic and ER stress-related signals. Collectively, these results demonstrate that MBP exposure exerts neuronal cytotoxicity via the interplay of ERK activation and Akt inactivation-regulated mitochondria-dependent and ER stress-triggered apoptotic pathway, which ultimately leads to neuronal cell death.

Ultrafine silicon dioxide nanoparticles cause lung epithelial cells apoptosis via oxidative stress-activated PI3K/Akt-mediated mitochondria- and endoplasmic reticulum stress-dependent signaling pathways.

Silicon dioxide nanoparticles (SiO2NPs) are widely applied in industry, chemical, and cosmetics. SiO2NPs is known to induce pulmonary toxicity. In this study, we investigated the molecular mechanisms of SiO2NPs on pulmonary toxicity using a lung alveolar epithelial cell (L2) model. SiO2NPs, which primary particle size was 12 nm, caused the accumulation of intracellular Si, the decrease in cell viability, and the decrease in mRNAs expression of surfactant, including surfactant protein (SP)-A, SP-B, SP-C, and SP-D. SiO2NPs induced the L2 cell apoptosis. The increases in annexin V fluorescence, caspase-3 activity, and protein expression of cleaved-poly (ADP-ribose) polymerase (PARP), cleaved-caspase-9, and cleaved-caspase-7 were observed. The SiO2NPs induced caspase-3 activity was reversed by pretreatment of caspase-3 inhibitor Z-DEVD-FMK. SiO2NPs exposure increased reactive oxygen species (ROS) production, decreased mitochondrial transmembrane potential, and decreased protein and mRNA expression of Bcl-2 in L2 cells. SiO2NPs increased protein expression of cytosolic cytochrome c and Bax, and mRNAs expression of Bid, Bak, and Bax. SiO2NPs could induce the endoplasmic reticulum (ER) stress-related signals, including the increase in CHOP, XBP-1, and phospho-eIF2α protein expressions, and the decrease in pro-caspase-12 protein expression. SiO2NPs increased phosphoinositide 3-kinase (PI3K) activity and AKT phosphorylation. Both ROS inhibitor N-acetyl-l-cysteine (NAC) and PI3K inhibitor LY294002 reversed SiO2NPs-induced signals described above. However, the LY294002 could not inhibit SiO2NPs-induced ROS generation. These findings demonstrated first time that SiO2NPs induced L2 cell apoptosis through ROS-regulated PI3K/AKT signaling and its downstream mitochondria- and ER stress-dependent signaling pathways.

Cr(VI) induces ROS-mediated mitochondrial-dependent apoptosis in neuronal cells via the activation of Akt/ERK/AMPK signaling pathway.

Hexavalent chromium (Cr(VI)), a well-known toxic industrial and environmental pollutant, has been shown to cause serious toxic and health effects. However, limited information is available on Cr(VI)-induced neurotoxic potential, with the underlying toxicological mechanisms remain mostly unclear. The present study demonstrated that the mitochondria-dependent apoptosis pathway was involved in Cr(VI)-induced SH-SY5Y cell (the human neuroblastoma cell line) death, which was accompanied by the appearance of cell shrinkage, increased mitochondrial membrane potential (MMP) depolarization and cytochrome c release, and the activation of caspase cascades and poly (ADP-ribose) polymerase (PARP). Cr(VI) treatment also increased the generation of intracellular reactive oxygen species (ROS). Pretreatment of SH-SY5Y cells with antioxidant N-acetylcysteine (NAC) effectively attenuated ROS production and reversed these Cr(VI)-induced cytotoxicity and apoptotic responses. Furthermore, exposure to Cr(VI) significantly increased the phosphorylation levels of Akt, extracellular regulated kinase (ERK)1/2, and AMP-activated protein kinase (AMPK)α. NAC and the pharmacological inhibitor of Akt (LY294002), ERK1/2 (PD980590), and AMPKα (Compound C) markedly abrogated the Cr(VI)-induced activation of Akt, ERK1/2, and AMPKα signal, respectively, with the concomitant inhibition of mitochondrial dysfunction and caspase activation. Additionally, all these inhibitors suppressed Cr(VI)-induced phosphorylation of Akt, ERK1/2, and AMPKα and of each other. Collectively, these results suggest that Cr(VI) exerts its cytotoxicity on neuronal cells by inducing mitochondria-dependent apoptosis through the interdependent activation of Akt, ERK1/2, and AMPKα, which are mainly mediated by ROS generation.

Challenges in the diagnosis of Boerhaave syndrome: A case report.

RATIONALE: Acute chest pain remains one of the most challenging complaints of patients presenting to emergency departments (EDs). The diverse etiologies of chest pain frequently lead to diagnostic and therapeutic challenges. Esophageal perforation is a rare but potentially life-threatening disease. It results in delayed diagnosis and an estimated mortality risk of 20% to 40%. Prompt diagnosis and immediate therapeutic interventions are key factors for a good prognosis. PATIENT CONCERNS: Case 1 involved a 66-year-old man who presented to the ED with acute chest pain radiating to the back and hematemesis. Emergent contrast thoracic computerized tomography (CT) indicated the presence of a massive pneumothorax with pleural effusion. The continuous drainage of a dark-red bloody fluid following emergent thoracic intubation led to the discovery that the patient had experienced severe vomiting after whiskey consumption before admission to the hospital. Re-evaluation of the CT indicated spontaneous pneumomediastinum, whereas barium esophagography confirmed the presence of an esophageal perforation. Case 2 involved an 18-year-old Vietnamese man admitted to our ED with acute chest pain and swelling of the neck after vomiting due to beer consumption. A chest x-ray indicated diffuse subcutaneous emphysema of the neck and upper thorax. Contrast CT indicated pneumomediastinum with extensive emphysema and air in the paraspinal region and spinal canal. DIAGNOSES: Both of the 2 cases were diagnosed as spontaneous perforation of the esophagus (Boerhaave syndrome [BS]). INTERVENTIONS: Case 1 received surgical interventions, whereas case 2 decided not to avail our medical services. OUTCOMES: Case 1 was discharged after a good recovery. Case 2 lost to follow-up. LESSONS: We recommend all physicians in the ED to raise their index of suspicion for BS when dealing with patients having acute chest pain, dyspnea, confirmed pneumothorax, or newly-developed pleural effusion.