Advanced oxidative protein products induced human keratinocyte apoptosis through the NOX–MAPK pathway

PINK1/Parkin-mediated mitophagy inhibits osteoblast apoptosis induced by advanced oxidation protein products

Osteoblast apoptosis plays an important role in age-related bone loss and osteoporosis. Our previous study revealed that advanced oxidation protein products (AOPPs) could induce nicotinamide adenine dinucleotide phosphate oxidase (NOX)-derived reactive oxygen species (ROS) production, cause mitochondrial membrane potential (ΔΨm) depolarization, trigger the mitochondria-dependent intrinsic apoptosis pathway, and lead to osteoblast apoptosis and ultimately osteopenia and bone microstructural destruction. In this study, we found that AOPPs also induced mitochondrial ROS (mtROS) generation in osteoblastic MC3T3-E1 cells, which was closely related to NOX-derived ROS, and aggravated the oxidative stress condition, thereby further promoting apoptosis. Removing excessive ROS and damaged mitochondria is the key factor in reversing AOPP-induced apoptosis. Here, by in vitro studies, we showed that rapamycin further activated PINK1/Parkin-mediated mitophagy in AOPP-stimulated MC3T3-E1 cells and significantly alleviated AOPP-induced cell apoptosis by eliminating ROS and damaged mitochondria. Our in vivo studies revealed that PINK1/Parkin-mediated mitophagy could decrease the plasma AOPP concentration and inhibit AOPP-induced osteoblast apoptosis, thus ameliorating AOPP accumulation-related bone loss, bone microstructural destruction and bone mineral density (BMD) loss. Together, our study indicated that therapeutic strategies aimed at upregulating osteoblast mitophagy and preserving mitochondrial function might have potential for treating age-related osteoporosis.

PINK1/Parkin-mediated mitophagy inhibits osteoblast apoptosis induced by advanced oxidation protein products

Osteoblast apoptosis plays an important role in age-related bone loss and osteoporosis. Our previous study revealed that advanced oxidation protein products (AOPPs) could induce nicotinamide adenine dinucleotide phosphate oxidase (NOX)-derived reactive oxygen species (ROS) production, cause mitochondrial membrane potential (ΔΨm) depolarization, trigger the mitochondria-dependent intrinsic apoptosis pathway, and lead to osteoblast apoptosis and ultimately osteopenia and bone microstructural destruction. In this study, we found that AOPPs also induced mitochondrial ROS (mtROS) generation in osteoblastic MC3T3-E1 cells, which was closely related to NOX-derived ROS, and aggravated the oxidative stress condition, thereby further promoting apoptosis. Removing excessive ROS and damaged mitochondria is the key factor in reversing AOPP-induced apoptosis. Here, by in vitro studies, we showed that rapamycin further activated PINK1/Parkin-mediated mitophagy in AOPP-stimulated MC3T3-E1 cells and significantly alleviated AOPP-induced cell apoptosis by eliminating ROS and damaged mitochondria. Our in vivo studies revealed that PINK1/Parkin-mediated mitophagy could decrease the plasma AOPP concentration and inhibit AOPP-induced osteoblast apoptosis, thus ameliorating AOPP accumulation-related bone loss, bone microstructural destruction and bone mineral density (BMD) loss. Together, our study indicated that therapeutic strategies aimed at upregulating osteoblast mitophagy and preserving mitochondrial function might have potential for treating age-related osteoporosis.

Advanced oxidation protein products mediate human keratinocytes apoptosis by inducing cell autophagy through the mTOR-Beclin-1 pathway

Excessive keratinocyte apoptosis leads to impaired wound healing. Recently, advanced oxidation protein products (AOPP) have been recognized as a marker of oxidative stress and a potent inducer of apoptosis. Previously, we have demonstrated that extracellular AOPP accumulation induced keratinocyte apoptosis, and we discovered that autophagy was involved. To further elucidate the role and mechanism of autophagy in AOPP-induced-apoptosis of keratinocytes, we treated HaCaT cells with increasing concentrations of AOPP-human serum albumin or with AOPP-human serum albumin for increasing durations. Cyto-ID solution staining was used to assess cell autophagy using confocal laser scanning microscopy. Autophagy-related protein interactions were investigated using western blot analysis. Exposure of HaCaT cells to AOPP decreased the expression of mammalian target of rapamycin (mTOR) and increased the expression of autophagy-related proteins Beclin-l and LC3, and eventually led to autophagy. Furthermore, an autophagy agonist significantly decreased the expression of apoptosis-related proteins. Taken together, we showed that accumulation of extracellular AOPP induced autophagy in HaCaT cells via a reactive oxygen species-dependent, mTOR-Beclin-1-mediated pathway, and that excessive autophagy-mediated apoptosis, which resulted in delayed wound healing.

TI: NLRP3 Inflammasome-Dependent Pyroptosis in CNS Trauma: A Potential Therapeutic Target

Central nervous system (CNS) trauma, including traumatic brain injury (TBI) and traumatic spinal cord injury (SCI), is characterized by high morbidity, disability, and mortality. TBI and SCI have similar pathophysiological mechanisms and are often accompanied by serious inflammatory responses. Pyroptosis, an inflammation-dependent programmed cell death, is becoming a major problem in CNS post-traumatic injury. Notably, the pyrin domain containing 3 (NLRP3) inflammasome is a key protein in the pyroptosis signaling pathway. Therefore, underlying mechanism of the NLRP3 inflammasome in the development of CNS trauma has attracted much attention. In this review, we briefly summarize the molecular mechanisms of NLRP3 inflammasome in pyroptosis signaling pathway, including its prime and activation. Moreover, the dynamic expression pattern, and roles of the NLRP3 inflammasome in CNS post-traumatic injury are summarized. The therapeutic applications of NLRP3 inflammasome activation inhibitors are also discussed.

Advanced Oxidation Protein Products Induce G1/G0-Phase Arrest in Ovarian Granulosa Cells via the ROS-JNK/p38 MAPK-p21 Pathway in Premature Ovarian Insufficiency

The mechanism underlying the role of oxidative stress and advanced oxidation protein products (AOPPs) in the aetiology of premature ovarian insufficiency (POI) is poorly understood. Here, we investigated the plasma AOPP level in POI patients and the effects of AOPPs on granulosa cells both in vitro and in vivo. KGN cells were treated with different AOPP doses, and cell cycle distribution, intracellular reactive oxygen species (ROS), and protein expression levels were measured. Sprague–Dawley (SD) rats were treated daily with PBS, rat serum albumin, AOPP, or AOPP+ N-acetylcysteine (NAC) for 12 weeks to explore the effect of AOPPs on ovarian function. Plasma AOPP concentrations were significantly higher in both POI and biochemical POI patients than in controls and negatively correlated with anti-Müllerian hormone and the antral follicle count. KGN cells treated with AOPP exhibited G1/G0-phase arrest. AOPP induced G1/G0-phase arrest in KGN cells by activating the ROS-c-Jun N-terminal kinase (JNK)/p38 mitogen-activated protein kinase (MAPK)-p21 pathway. Pretreatment with NAC, SP600125, SB203580, and si-p21 blocked AOPP-induced G1/G0-phase arrest. In SD rats, AOPP treatment increased the proportion of atretic follicles, and NAC attenuated the adverse effects of AOPPs in the ovary. In conclusion, we provide mechanistic evidence that AOPPs may induce cell cycle arrest in granulosa cells via the ROS-JNK/p38 MAPK-p21 pathway and thus may be a novel biomarker of POI.

NOX2 Expression Is Increased in Keratinocytes After Burn Injury

Reepithelialization is crucial for effective wound repair in burn wounds. Reactive oxygen species (ROS) have shown to be important in this. Recent studies suggest that NOX proteins produce ROS in keratinocytes. In the present study, we have studied NOX proteins in burn wounds, including the effect of C1-esterase inhibitor (C1inh) hereon, which is the endogenous inhibitor of complement activity whereof we have shown previously that it also increased the rate of reepithelialization in burn wounds. Skin tissue derived from healthy control Wistar rats (n = 6) were compared with burn-injured rats, with (n = 7) or without C1inh treatment (n = 7). After 14 days, rats were terminated. From the burn-injured rats, the entire wound and nonburned skin from the hind leg, that is, internal control was excised. From the control rats, dorsal skin was excised. In these skin samples, NOX2 and NOX4 were analyzed immunohistochemically. In nonburned rats, NOX2 was found in keratinocytes in both the basal layer and suprabasal layer of the epidermis; and the number of NOX2-positive keratinocytes was 367/mm2 (254-378). In burned rats, the number of NOX2-positive keratinocytes was significantly increased in the newly forming epidermis in the burned area to 1019/mm2 (649-1172), especially in the suprabasal layer, but significantly decreased in remote nonburned skin to 22/mm2 (6-89). C1inh treatment counteracted these changes in epidermal NOX2 expression in burned rats, both in the burned area as in remote nonburned skin. No NOX4 expression was found in the epidermis in none of the groups. NOX2 expression was increased in keratinocytes in newly forming epidermis after burn injury. C1inh, a drug that increases the rate of reepithelialization, counteracted this effect. These results suggest a role for NOX2 in the reepithelialization of burn wounds.

The Viability and Growth of HaCaT Cells After Exposure to Bioactive Glass S53P4-Containing Cell Culture Media

HYPOTHESIS

Bioactive glass (BG) S53P4 reduces the viability of epidermal keratinocyte-derived immortalized cell line, HaCaT in sufficient concentrations in vitro.

BACKGROUND

Although used in mastoid obliteration surgery, there is no data available on whether BG S53P4 granules have an inhibitory or excitatory effect on keratinocytes, found in normal skin and ear cholesteatoma in vivo.

METHODS

HaCaT cell cultures were incubated with a direct BG S53P4 granule contact. Microscopic evaluation of the cultures was performed and interleukin-6 (IL-6) and -8 (IL-8) concentrations were measured from the medium samples. In addition, BG granules were incubated in two cell culture media for 6 days and the pure media were used in confluent HaCaT cultures preceding cell viability assay. Finally, a scratch assay test was performed to reveal the possible BG effect on HaCaT cultures.

RESULTS

Eight to ten cell thick layers of dead HaCaT cells were noticed after a 2-day BG granule contact. With a BG concentration of 2.5%, IL-6 and IL-8 concentrations were smaller compared with the control group without BG after 2 days' incubation. Overall, HaCaT cell viability decreased when BG was incubated in keratinocyte growth medium, but did not change in Dulbecco's modified Eagle's medium. In a scratch assay test, cell regrowth in the scratch area was notable in cultures without BG.

CONCLUSIONS

BG S53P4 seems to have an inhibitory effect on HaCaT cell growth. Although further studies are needed, this observation seems advantageous for cholesteatoma treatment.

Protein Kinase-Mediated Decision Between the Life and Death

Protein kinases are intracellular signaling enzymes that catalyze the phosphorylation of specific residues in their target substrate proteins. They play important role for regulation of life and death decisions. The complexity of the relationship between death receptors and protein kinases' cell death decision-making mechanisms create many difficulties in the treatment of various diseases. The most of fifteen different cell death pathways, which are reported by Nomenclature Committee on Cell Death (NCCD) are protein kinase signal transduction-mediated negative or positive selections. Tumor necrosis factor (TNF) as a main player of death pathways is a dual-functioning molecule in that it can promote both cell survival or cell death. All apoptotic and necrotic signal transductions are conveyed through death domain-containing death receptors, which are expressed on the surface of nearly all human cells. In humans, eight members of the death receptor family have been identified. While the interaction of TNF with TNF Receptor 1 (TNFR1) activates various signal transduction pathways, different death receptors activate three main signal transduction pathways: nuclear factor kappa B (NF-ĸB)-mediated differentiation or pro-inflammatory cytokine synthesis, mitogen-activated protein kinase (MAPK)-mediated stress response and caspase-mediated apoptosis. The link between the NF-ĸB and the c-Jun NH₂-terminal kinase (JNK) pathways comprise another check-point to regulate cell death. TNF-α also promotes the "receptor-interacting serine/threonine protein kinase 1" (RIPK1)/RIPK3/ mixed lineage kinase domain-like pseudokinase (MLKL)-dependent necrosis. Thus, necrosome is mainly comprised of MLKL, RIPK3 and, in some cases, RIPK1. In fact, RIPK1 is at the crossroad between life and death, downstream of various receptors as a regulator of endoplasmic reticulum stress-induced death. TNFR1 signaling complex (TNF-RSC), which contains multiple kinase activities, promotes phosphorylation of transforming growth factor β-activated kinase 1 (TAK1), inhibitor of nuclear transcription factor κB (IκB) kinase (IKK) α/IKKβ, IκBα, and NF-κB. IKKs affect cell-survival pathways in NF-κB-independent manner. Toll-like receptor (TLR) stimulation triggers various signaling pathways dependent on myeloid differentiation factor-88 (MyD88), Interleukin-1 receptor (IL-1R)-associated kinase (IRAK1), IRAK2 and IRAK4, lead to post-translational activation of nucleotide and oligomerization domain (NLRP3). Thereby, cell fate decisions following TLR signaling is parallel with death receptor signaling. Inhibition of IKKα/IKKβ or its upstream activators sensitize cells to death by inducing RIPK1-dependent apoptosis or necroptosis. During apoptosis, several kinases of the NF-κB pathway, including IKK1 and NF-κB essential modulator (NEMO), are cleaved by cellular caspases. This event can terminate the NF-κB-derived survival signals. In both canonical and non-canonical pathways, IKK is key to NF-κB activation. Whereas, the activation process of IKK, the functions of NEMO ubiquitination, IKK-related non-canonical pathway and the nuclear transportation of NEMO and functions of IKKα are still debated in cell death. In addition, cluster of differentiation 95 (CD95)-mediated non-apoptotic signaling and CD95- death-inducing signaling complex (DISC) interactions are waiting for clarification.

Burn injury induces elevated inflammatory traffic: the role of NF-κB

A burn insult generally sustains a hypovolemic shock due to a significant loss of plasma from the vessels. The burn injury triggers the release of various mediators, such as reactive oxygen species (ROS), cytokines, and inflammatory mediators. Damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs), stemming from foreign microbial discharge and damaged tissue or necrotic cells from the burn-injured site, enter the systemic circulation, activate toll-like receptors (TLRs), and trigger the excessive secretion of cytokines and inflammatory mediators. Inflammation plays a vital role in remodeling an injured tissue, detoxifying toxins, and helps in the healing process. A transcription factor, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), contributes to a variety of physiological and pathological conditions, including immune response, cell death, cell survival, and inflammatory processes. During the pathogenesis of a burn wound, upregulation of various cytokines and growth factors lead to undesirable tissue inflammation. Thus, NF-κB, a dominant moderator of inflammation, needs to be altered to prove beneficial to the treatment of burns or other inflammation-associated diseases. This review addresses the relationship between NF-κB and elevated inflammation in a burn condition that could potentially be altered to induce an early wound-healing mechanism of burn wounds.

Engagement of MicroRNA-155 in Exaggerated Oxidative Stress Signal and TRPA1 in the Dorsal Horn of the Spinal Cord and Neuropathic Pain During Chemotherapeutic Oxaliplatin

Oxaliplatin (OXL) is a third-generation chemotherapeutic agent commonly used to treat metastatic digestive tumors, but one of the main limiting complications of OXL is painful peripheral neuropathy. The present study was to examine the inhibitory effects of blocking microRNA-155 (miR-155) in the dorsal horn of the spinal cord on neuropathic pain induced by OXL in rats and the underlying mechanisms. Behavioral test was performed to examine mechanical pain and cold sensitivity in rats. Real-time RT-PCR and ELISA were employed to determine miR-155 and products of oxidative stress 8-isoprostaglandin F2α (8-iso PGF2α) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the dorsal horn. Western blot analysis was used to examine expression of Nrf2-antioxidant response element (Nrf2-ARE), NADPH oxidases (NOXs), and transient receptor potential ankyrin 1 (TRPA1). In results, intrathecal administration of miR-155 inhibitor attenuated mechanical allodynia and cold hyperalgesia in rats with OXL therapy and this was accompanied with restoring of impaired Nrf2-ARE in the dorsal horn. A blockade of miR-155 also attenuated expression of NOX subtype 4 (NOX4) and thereby decreased the levels of 8-iso PGF2α/8-OHdG in the dorsal horn of OXL rats. In addition, inhibiting NOX4 decreased products of oxidative stress in the dorsal horn and attenuated upregulation of TRPA1 induced by OXL. In conclusion, data show the critical role of miR-155 in regulating OXL-induced neuropathic pain likely via oxidative stress-TRPA1 signal pathway, indicating that inhibition of miR-155 has potential benefits in preventing neuropathic pain development during intervention of OXL.

The Essential Role of Ca2+ Signals in UVB-Induced IL-1β Secretion in Keratinocytes

UVB-induced skin damage is attributable to reactive oxygen species, which are triggered by intracellular Ca²⁺ signals. However, exactly how the reactive oxygen species are triggered by intracellular Ca²⁺ upon UVB irradiation remains obscure. Here, we show that UVB induces Ca²⁺ signals via sequential generation of the following Ca²⁺ messengers: inositol 1,4,5-trisphosphate, nicotinic acid adenine dinucleotide phosphate, and cyclic ADP-ribose. UVB induced H₂O₂ production through NADPH oxidase 4 activation, which is downstream to inositol 1,4,5-trisphosphate and nicotinic acid adenine dinucleotide phosphate. H₂O₂ derived from NADPH oxidase 4 activated CD38 to produce cyclic ADP-ribose. UVB first evoked the pannexin channel to release ATP, which acts on P2X7 receptor to generate inositol 1,4,5-trisphosphate. Inhibitors of these messengers, as well as antioxidants, blocked UVB-induced Ca²⁺ signals and IL-1β secretion in keratinocytes. Furthermore, ablation of CD38 and NADPH oxidase 4 protected against UVB-induced inflammation and IL-1β secretion in the murine epidermis. These results show that UVB induces IL-1β secretion through cross-talk between Ca²⁺ and reactive oxygen species, providing insight towards potential targets against UVB-induced inflammation.

NADPH Oxidases and Their Roles in Skin Homeostasis and Carcinogenesis

SIGNIFICANCE

Skin protects the body from dehydration, pathogens, and external mutagens. NADPH oxidases are central components for regulating the cellular redox balance. There is increasing evidence indicating that reactive oxygen species (ROS) generated by members of this enzyme family play important roles in the physiology and pathophysiology of the skin. Recent Advances: NADPH oxidases are active producers of ROS such as superoxide and hydrogen peroxide. Different isoforms are found in virtually all tissues. They play pivotal roles in normal cell homeostasis and in the cellular responses to various stressors. In particular, these enzymes are integral parts of redox-sensitive prosurvival and proapoptotic signaling pathways, in which they act both as effectors and as modulators. However, continuous (re)activation of NADPH oxidases can disturb the redox balance of cells, in the worst-case scenario in a permanent manner. Abnormal NADPH oxidase activity has been associated with a wide spectrum of diseases, as well as with aging and carcinogenesis.

CRITICAL ISSUES

Sunlight with its beneficial and deleterious effects induces the activation of NADPH oxidases in the skin. Evidence for the important roles of this enzyme family in skin cancer and skin aging, as well as in many chronic skin diseases, is now emerging.

FUTURE DIRECTIONS

Understanding the precise roles of NADPH oxidases in normal skin homeostasis, in the cellular responses to solar radiation, and during carcinogenesis will pave the way for their validation as therapeutic targets not only for the prevention and treatment of skin cancers but also for many other skin-related disorders. Antioxid. Redox Signal. 28, 1238-1261.

Advanced oxidation protein products induce hepatocyte epithelial-mesenchymal transition via a ROS-dependent, TGF-β/Smad signaling pathway

Epithelial-mesenchymal transition (EMT) occurs during the progression of liver fibrosis in response to chronic liver injury. However, the molecular mechanism underlying the regulation of hepatocyte EMT remains unclear. The aim of this study was to determine whether advanced oxidation protein products (AOPP) had an effect on hepatocyte EMT. The human L02 hepatocyte cell line and hepatocytes from normal Sprague-Dawley rats were challenged with AOPP treatment in both in vitro and in vivo studies. The expression of cell and molecular markers of EMT in L02 hepatocytes were studied using Western blotting, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assays. Hepatocyte migratory potential was analyzed using a wound healing assay. Intracellular reactive oxygen species (ROS) were detected using the dichlorofluorescein (DCF) assay. In liver tissue sections, expression of EMT markers was evaluated using immunohistochemistry, and collagen was assessed using histochemical staining with Masson's trichrome. The findings were that AOPP treatment resulted in EMT in hepatocytes, which was associated with reduced expression of E-cadherin, increased expression of vimentin, increased deposition of collagen protein, and enhanced cell migration in vivo and in vitro. AOPP was also found to promote migration in L02 cells, and to promote the production of ROS and the activation of TGF-βR and Smad signaling. Inhibition of the generation of intracellular ROS and TGF-β receptor blocking could reverse AOPP-induced EMT in hepatocytes. This study has identified a novel mechanism in the regulation of hepatocyte EMT, and the findings may have implications for the control of liver fibrosis.

Advanced Oxidative Protein Products Cause Pain Hypersensitivity in Rats by Inducing Dorsal Root Ganglion Neurons Apoptosis via NADPH Oxidase 4/c-Jun N-terminal Kinase Pathways

Pain hypersensitivity is the most common category of chronic pain and is difficult to cure. Oxidative stress and certain cells apoptosis, such as dorsal root ganglion (DRG) neurons, play an essential role in the induction and development of pain hypersensitivity. The focus of this study is at a more specific molecular level. We investigated the role of advanced oxidative protein products (AOPPs) in inducing hypersensitivity and the cellular mechanism underlying the proapoptotic effect of AOPPs. Normal rats were injected by AOPPs-Rat serum albumin (AOPPs–RSA) to cause pain hypersensitivity. Primary cultured DRG neurons were treated with increasing concentrations of AOPPs–RSA or for increasing time durations. The MTT, flow cytometry and western blot analyses were performed in the DRG neurons. A loss of mitochondrial membrane potential (MMP) and an increase in intracellular reactive oxygen species (ROS) were observed. We found that AOPPs triggered DRG neurons apoptosis and MMP loss. After AOPPs treatment, intracellular ROS generation increased in a time- and dose-dependent manner, whereas, N-acetyl-L-cysteine (NAC), a specific ROS scavenger could inhibit the ROS generation. Proapoptotic proteins, such as Bax, caspase 9/caspase 3, and PARP-1 were activated, whereas anti-apoptotic Bcl-2 protein was down-regulated. AOPPs also increased Nox4 and JNK expression. Taken together, these findings suggest that AOPPs cause pain hypersensitivity in rats, and extracellular AOPPs accumulation triggered Nox4-dependent ROS production, which activated JNK, and induced DRG neurons apoptosis by activating caspase 3 and PARP-1.

IKKα regulates human keratinocyte migration through surveillance of the redox environment

Although the functions of H₂O₂ in epidermal wound repair are conserved throughout evolution, the underlying signaling mechanisms are largely unknown. In this study we used human keratinocytes (HEK001) to investigate H₂O₂-dependent wound repair mechanisms. Scratch wounding led to H₂O₂ production in two or three cell layers at the wound margin within ∼30 min and subsequent cysteine modification of proteins via sulfenylation. Intriguingly, exogenous H₂O₂ treatment resulted in preferential sulfenylation of keratinocytes that adopted a migratory phenotype and detached from neighboring cells, suggesting that one of the primary functions of H₂O₂ is to stimulate signaling factors involved in cell migration. Based on previous findings that revealed epidermal growth factor receptor (EGFR) involvement in H₂O₂-dependent cell migration, we analyzed oxidation of a candidate upstream target, the inhibitor of κB kinase α (IKKα; encoded by CHUK), as a mechanism of action. We show that IKKα is sulfenylated at a conserved cysteine residue in the kinase domain, which correlates with de-repression of EGF promoter activity and increased EGF expression. Thus, this indicates that IKKα promotes migration through dynamic interactions with the EGF promoter depending on the redox state within cells.

Summary: This study provides a newly identified mechanism by which H₂O₂-dependent oxidation of the inhibitor of κB kinase α and de-repression of epidermal growth factor promoter activity stimulates keratinocyte migration.

Tricholoma matsutake Aqueous Extract Induces Hepatocellular Carcinoma Cell Apoptosis via Caspase-Dependent Mitochondrial Pathway

Tricholoma matsutake, one of widely accepted functional mushrooms, possesses various pharmacological activities, and its antitumor effect has become an important research point. Our study aims to evaluate the cytotoxicity activities of T. matsutake aqueous extract (TM) in HepG2 and SMMC-7721 cells. In in vitro experiments, TM strikingly reduced cell viability, promoted cell apoptosis, inhibited cell migration ability, induced excessive generation of ROS, and caused caspases cascade and mitochondrial membrane potential dissipation in hepatocellular carcinoma cells. In in vivo experiments, 14-day TM treatment strongly suppressed tumor growth in HepG2 and SMMC-7721-xenografted nude mice without influence on their body weights and liver function. Furthermore, TM increased the levels of cleaved poly-ADP-ribose polymerase (PARP), Bad, and Bax and reduced the expressions of B-cell lymphoma 2 (Bcl-2) in treated cells and tumor tissues. All aforementioned results suggest that caspase-dependent mitochondrial apoptotic pathways are involved in TM-mediated antihepatocellular carcinoma.

Tricholoma matsutake Aqueous Extract Induces Hepatocellular Carcinoma Cell Apoptosis via Caspase-Dependent Mitochondrial Pathway

Tricholoma matsutake, one of widely accepted functional mushrooms, possesses various pharmacological activities, and its antitumor effect has become an important research point. Our study aims to evaluate the cytotoxicity activities of T. matsutake aqueous extract (TM) in HepG2 and SMMC-7721 cells. In in vitro experiments, TM strikingly reduced cell viability, promoted cell apoptosis, inhibited cell migration ability, induced excessive generation of ROS, and caused caspases cascade and mitochondrial membrane potential dissipation in hepatocellular carcinoma cells. In in vivo experiments, 14-day TM treatment strongly suppressed tumor growth in HepG2 and SMMC-7721-xenografted nude mice without influence on their body weights and liver function. Furthermore, TM increased the levels of cleaved poly-ADP-ribose polymerase (PARP), Bad, and Bax and reduced the expressions of B-cell lymphoma 2 (Bcl-2) in treated cells and tumor tissues. All aforementioned results suggest that caspase-dependent mitochondrial apoptotic pathways are involved in TM-mediated antihepatocellular carcinoma.

Cinnamaldehyde ameliorates LPS-induced cardiac dysfunction via TLR4-NOX4 pathway: The regulation of autophagy and ROS production

Cinnamaldehyde (CA), a major bioactive compound extracted from the essential oil of Cortex Cinnamomi, exhibits anti-inflammatory activity on endotoxemia. Accumulating evidence indicates reactive oxygen species (ROS) and autophagy play a vital role in the cardiac dysfunction during endotoxemia. The aim of this study was to unveil the mechanism of CA on ROS production and autophagy during endotoxemia. Male Sprague-Dawley rats were stimulated by LPS (20mg/kg i.v.) with or without treatment of CA. Cardiac function and histopathological staining were preformed 4h after LPS stimulation. The levels of TNF-α, IL-1β and IL-6 were detected by ELISA. The expression of p-JNK, p-ERK, p-p38, TLR4, NOX4, NOX2, ATG5 and LC3 proteins were determined by Western blot. The results showed that CA inhibited cardiac dysfunction, inflammatory infiltration and the levels of TNF-α, IL-1β and IL-6 in LPS stimulated rats by blocking the TLR4, NOX4, MAPK and autophagy signalings. In order to obtain further confirmation of the mechanism of CA on endotoxemia in vitro, a limited time-course study was firstly performed by Western blot. TLR4, NOX4 and LC3 were significantly increased after 4h LPS stimulation. CA reversed the intracellular ROS production and MAPK signaling activation induced by LPS. Electron microscopy, mRFP-GFP-LC3 transfection and western blot results revealed autophagic flux were attenuated after CA treatment. The siRNA and molecular docking results suggest that CA can suppress both TLR4 and NOX4 during endotoxemia. Our data revealed that CA ameliorated LPS-induced cardiac dysfunction by inhibiting ROS production and autophagy through TLR4-NOX4 pathway.