Heme oxygenase-1 induction by (S)-enantiomer of YS-51 (YS-51S), a synthetic isoquinoline alkaloid, inhibits nitric oxide production and nuclear factor-kappaB translocation in ROS 17/2.8 cells activated with inflammatory stimulants

Euphorbia factor L3 ameliorates rheumatoid arthritis by suppressing the inflammatory response by targeting Rac family small GTPase 1

Euphorbia factor L3 (EFL3) is extracted from Euphorbia lathyris and is known for its anti-inflammatory properties. This study focused on the potential anti-inflammatory and therapeutic effects of EFL3 on rheumatoid arthritis (RA) using fibroblast-like synoviocytes (FLSs) and arthritis animal models. Functional analysis showed that EFL3 could ameliorate the inflammatory phenotype of FLSs derived from RA patients, as evidenced by the decreases in cell viability, migration, invasion and cytokine production. Luciferase activity, Western blotting and immunofluorescence assays demonstrated that EFL3 inhibited the nuclear translocation of the p65 subunit and the subsequent activation of the nuclear factor kappa-Β (NF-κB) pathway. Furthermore, the therapeutic effects of EFL3 against arthritic progression were evidenced by decreases in joint swelling, arthritis scores, inflammatory factor production, synovial hyperplasia, and bone destruction in collagen-induced arthritis (CIA) and tumor necrosis factor-α (TNF-α) transgenic (TNF-tg) mouse models. Molecular analysis identified Rac family small GTPase 1 (Rac1) as the potential target that was required for EFL3-mediated suppression of the inflammatory RA FLS phenotype. In summary, this study uncovered the therapeutic potential of EFL3 in RA, which suggests its future clinical use.

Apoptosis, Autophagy, NETosis, Necroptosis, and Pyroptosis Mediated Programmed Cell Death as Targets for Innovative Therapy in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that can lead to clinical manifestations of systemic diseases. Its leading features include chronic synovial inflammation and degeneration of the bones and joints. In the past decades, multiple susceptibilities for rheumatoid arthritis have been identified along with the development of a remarkable variety of drugs for its treatment; which include analgesics, glucocorticoids, nonsteroidal anti-inflammatory medications (NSAIDs), disease-modifying anti-rheumatic drugs (DMARDs), and biologic response modifiers (bDMARDs). Despite the existence of many clinical treatment options, the prognosis of some patients remains poor due to complex mechanism of the disease. Programmed cell death (PCD) has been extensively studied and ascertained to be one of the essential pathological mechanisms of RA. Its dysregulation in various associated cell types contributes to the development of RA. In this review, we summarize the role of apoptosis, cell death-associated neutrophil extracellular trap formation, necroptosis, pyroptosis, and autophagy in the pathophysiology of RA to provide a theoretical reference and insightful direction to the discovery and development of novel therapeutic targets for RA.

The Pathogenic Role of Foam Cells in Atherogenesis: Do They Represent Novel Therapeutic Targets?

BACKGROUND

Foam cells, mainly derived from monocytes-macrophages, contain lipid droplets essentially composed of cholesterol in their cytoplasm. They infiltrate the intima of arteries, contributing to the formation of atherosclerotic plaques.

PATHOGENESIS

Foam cells damage the arterial cell wall via the release of proinflammatory cytokines, free radicals, and matrix metalloproteinases, enhancing the plaque size up to its rupture.

THERAPY

A correct dietary regimen seems to be the most appropriate therapeutic approach to minimize obesity, which is associated with the formation of foam cells. At the same time, different types of antioxidants have been evaluated to arrest the formation of foam cells, even if the results are still contradictory. In any case, a combination of antioxidants seems to be more efficient in the prevention of atherosclerosis.

HO-1 in Bone Biology: Potential Therapeutic Strategies for Osteoporosis

Osteoporosis is a prevalent bone disorder characterized by bone mass reduction and deterioration of bone microarchitecture leading to bone fragility and fracture risk. In recent decades, knowledge regarding the etiological mechanisms emphasizes that inflammation, oxidative stress and senescence of bone cells contribute to the development of osteoporosis. Studies have demonstrated that heme oxygenase 1 (HO-1), an inducible enzyme catalyzing heme degradation, exhibits anti-inflammatory, anti-oxidative stress and anti-apoptosis properties. Emerging evidence has revealed that HO-1 is critical in the maintenance of bone homeostasis, making HO-1 a potential target for osteoporosis treatment. In this Review, we aim to provide an introduction to current knowledge of HO-1 biology and its regulation, focusing specifically on its roles in bone homeostasis and osteoporosis. We also examine the potential of HO-1-based pharmacological therapeutics for osteoporosis and issues faced during clinical translation.

Costimulation of Murine Osteoblasts with Interferon-γ and Tumor Necrosis Factor-α Induces Apoptosis through Downregulation of Bcl-2 and Release of Cytochrome c from Mitochondria

During chronic inflammation from diseases, such as periodontal disease, the proinflammatory cytokines interferon-gamma (IFNγ) and tumor necrosis factor-α (TNFα) alter bone remodeling. To elucidate the underlying molecular mechanisms, we investigated the effect of IFNγ and TNFα on the proliferation and survival of clonal MC3T3-E1 mouse osteoblasts. We found that although IFNγ or TNFα alone affected cell growth and survival only marginally, costimulation with both synergistically inhibited cell growth and reduced cell viability. The diminished cell viability was due to apoptosis, as indicated by increased TUNEL staining and elevated caspase 3, 8, and 9 activities. Western blot also showed that costimulation with IFNγ and TNFα elicited cytochrome c release and downregulated B cell lymphoma 2 (Bcl-2) expression without affecting Bcl-2-associated X (Bax) protein expression. Furthermore, stable Bcl-2 overexpression significantly alleviated cell death following costimulation. Collectively, these results suggested that IFNγ and TNFα elicited osteoblast apoptosis via cytochrome c release from damaged mitochondria, caspase activation, and Bcl-2 downregulation.

(S)YS-51, a novel isoquinoline alkaloid, attenuates obesity-associated non-alcoholic fatty liver disease in mice by suppressing lipogenesis, inflammation and coagulation

Obesity-associated non-alcoholic fatty liver disease (NAFLD) increases coagulation and inflammation. We hypothesized that (S)YS-51, an agent found to be beneficial in animal models of sepsis, may reduce NAFLD in high-fat diet (HFD) mice by reducing coagulation and inflammation. C57BL/6 mice were fed either a chow diet or HFD and each was supplemented with or without (S)YS-51 (10mg/kg, daily, i.p.) for 16 weeks. The results showed that HFD caused significant increases in lipogenesis [CD36, fatty acid synthase (FAS) and sterol response element binding protein (SREBP)-1c mRNA and protein], inflammation [monocyte chemotactic protein (MCP)-1, tumor necrosis factor (TNF)-α, intercellular cell adhesion molecule-1 (ICAM-1), TGF-β, and procollagen type 1 mRNA, macrophage infiltration] and coagulation [tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) mRNA and thrombin antithrombin complex (TAT)] in the liver, adipose tissue and serum, which were significantly reduced by (S)YS-51. These results of (S)YS-51 were accompanied by significant reduction of weight gain, liver size, hepatic steatosis and fibrosis, blood cholesterol, hepatic triglyceride, and macrophage infiltration and inflammatory cytokines in adipose tissue without affecting food intake in HFD mice. Interestingly, (S)YS-51 increased SIRT1 mRNA and protein and AMPK expression in the liver of HFD mice by increasing both NAD(+)/NADH ratio and LKB1 phosphorylation. In HepG2 cells, (S)YS-51 activated SIRT1 followed by AMPK. Finally, (S)YS-51 improved glucose tolerance and insulin resistance in HFD mice. We concluded that (S)YS-51 attenuates NAFLD and insulin resistance in HFD mice by, at least, activation of SIRT1/AMPK signals. Thus, (S)YS-51 may be beneficial in NAFLD treatment.

2-Acetyl-7-hydroxy-6-methoxy-1-methyl-1,2,3,4,-tetrahydroisoquinoline exhibits anti-inflammatory properties and protects the nigral dopaminergic neurons

Parkinson's disease (PD) is a neurodegenerative disorder characterized by degeneration of dopamine(DA)ergic neurons. Neuroinflammation caused by microglial activation is believed to be involved in the pathogenesis of neurodegenerative diseases including PD. In the present study, we tested the effects of a novel compound 2-acetyl-7-hydroxy-6-methoxy-1-methyl-1,2,3,4,-tetarhydroisoquinoline (AMTIQ) on neuroinflammatory response and DAergic neurodegeneration. In lipopolysaccharide-activated BV-2 microglial cells, AMTIQ lowered nitric oxide and tetrahydrobiopterin levels and downregulated gene expression of inducible nitric oxide synthase and GTP cyclohydrolase I. AMTIQ also repressed gene expression of the proinflammatory cytokines IL-1β and TNF-α, and attenuated nuclear translocation of NF-κB. AMTIQ was stable against liver microsomal enzymes from human and mouse and did not interfere with activities of the cytochrome p450 enzymes 1A2, 2D6, 2C9, 2C19 and 3A4. Pharmacokinetic studies revealed the brain to plasma ratio of AMTIQ to be 45%, suggesting it can penetrate the blood brain barrier. In 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mouse PD model, AMTIQ led to decreased microglial activation, increased survival of DAergic neurons and their fibers, and improved behavioral scores on rotarod and vertical grid tests. Taken together, these results suggest that AMTIQ might serve as a candidate preventive-therapeutic agent for neurodegenerative diseases such as PD.

Antioxidative nanofullerol prevents intervertebral disk degeneration

Compelling evidence suggests that reactive oxygen species (ROS) play a pivotal role in disk degeneration. Fullerol nanoparticles prepared in aqueous solution have been demonstrated to have outstanding ability to scavenge ROS. In this report, in vitro and in vivo models were used to study the efficacy of fullerol in preventing disk degeneration. For in vitro experiments, a pro-oxidant H₂O₂ or an inflammatory cytokine interleukin (IL)-1β was employed to induce degenerated phenotypes in human nucleus pulposus cells encapsulated in alginate beads, and fullerol was added in the culture medium. For the animal study, an annulus-puncture model with rabbit was created, and fullerol was injected into disks. It was shown that cytotoxicity and cellular ROS level induced by H₂O₂ were significantly diminished by fullerol. IL-1β-induced nitric oxide generation in culture medium was suppressed by fullerol as well. Gene-profile and biochemical assays showed that fullerol effectively reversed the matrix degradation caused by either H₂O₂ or IL-1β. The animal study delineated that intradiskal injection of fullerol prevented disk degeneration, increasing water and proteoglycan content and inhibiting ectopic bone formation. These results suggest that antioxidative fullerol may have a potential therapeutic application for disk degeneration.

BMD values and GSTM3 gene polymorphisms in combination with GSTT1/GSTM1 genes: a genetic association study in Slovenian elderly

BACKGROUND

Much research suggests that oxidative stress is associated with osteoporosis development. Glutathione S-transferases mu3 (GSTM3) are an important group of detoxifying enzymes that eliminate oxidative stress-related products.

OBJECTIVES

To examine the associations of functional GSTM3 gene polymorphisms (Val224Ile and insdelAGG), their haplotypes and, in combination with GSTT1-null and GSTM1-null polymorphisms, with bone mineral density (BMD) measured at femoral neck (_fn), lumbar spine (_ls) and total hip (_th) and biochemical bone turnover markers in 593 Slovenian elderly women and 119 Slovenian elderly men.

METHODS

GSTM3, GSTT1-null and GSTM1-null gene polymorphisms using sizing denaturing high-performance liquid chromatography, triplex PCR method or real-time PCR; BMD_fn, BMD_ls, BMD_th values using dual energy X-ray absorptiometry, and plasma osteocalcin, serum bone alkaline phosphatase and free soluble tumor necrosis factor (ligand) superfamily, member 11 (sRANKL) concentrations using a solid-phase, two-site chemiluminescent enzyme-labeled immunometric assay, radioimmunoassay or enzyme immunoassay were determined. Statistical analysis was performed using one-way and two-way ANCOVA with adjustment for potential confounders (age, height and weight).

RESULTS

The (borderline) significant differences in BMD_th and BMD_fn values between genotype subgroups of Val224Ile polymorphism of GSTM3 gene (p = 0.057 and 0.053, respectively) with the lowest BMD values among heterozygotes and between 224Ile-insAGG haplotype subgroups (p = 0.048 and 0.019, respectively) were found. Significant differences of BMD_fn between the 224Ile-delAGG haplotype subgroups were observed (p = 0.012). Association of 224Val-insAGG with BMD_fn was of borderline significance (p = 0.062).

CONCLUSION

The results of our study demonstrate the genetic association between detoxifying enzyme GSTM3 and BMD variation, suggesting that the Val224Ile polymorphism and 224Ile-insAGG haplotype could be used for further evaluation of the impact of GSTs gene polymorphisms on osteoporosis, using larger cohorts in searching for osteoporosis risk markers.

Upregulation of heme oxygenase-1 inhibits the maturation and mineralization of osteoblasts

Heme-oxygenase-1 (HO-1), an important enzyme involved in vascular disease, transplantation, and inflammation, catalyzes the degradation of heme into carbon monoxide and biliverdin. It has been reported that overexpression of HO-1 inhibits osteoclastogenesis. However, the effect of HO-1 on osteoblast differentiation is still not clear. We here used adenoviral vector expressing recombinant human HO-1 and HO-1 inducer hemin to study the effects of HO-1 in primary cultured osteoblasts. The results showed that induction of HO-1 inhibited the maturation of osteoblasts including mineralized bone nodule formation, alkaline phosphatase activity and decreased mRNA expression of several differentiation markers such as alkaline phosphatase, osteocalcin, and RUNX2. Furthermore, downstream products of HO-1, bilirubin, carbon monoxide, and iron, are involved in the inhibitory action of HO-1. HO-1 can be induced by H(2)O(2), lipopolysaccharide and inflammatory cytokines such as TNF-alpha and IL-1beta in osteoblasts and also in STZ-induced diabetic mice. In addition, endogenous PPARgamma ligand, 15-deoxy-Delta(12,14)-prostaglandin-J2 (15d-PGJ2) markedly increased both mRNA and protein levels of HO-1 in osteoblasts via PI3K-Akt and MAPK pathways. Blockade of HO activity by ZnPP IX antagonized the inhibitory action on osteocalcin expression by hemin and 15d-PGJ2. Our results indicate that upregulation of HO-1 inhibits the maturation of osteoblasts and HO-1 may be involved in oxidative- or inflammation-induced bone loss.

The Role of Nrf2 in Cellular Innate Immune Response to Inflammatory Injury

Nuclear factor erythroid derived 2-related factor-2 (Nrf2) is a master transcription regulator of antioxidant and cytoprotective proteins that mediate cellular defense against oxidative and inflammatory stresses. Disruption of cellular stress response by Nrf2 deficiency causes enhanced susceptibility to infection and related inflammatory diseases as a consequence of exacerbated immuneediated hypersensitivity and autoimmunity. The cellular defense capacity potentiated by Nrf2 activation appears to balance the population of CD4⁺ and CD8⁺ of lymph node cells for proper innate immune responses. Nrf2 can negatively regulate the activation of pro-inflammatory signaling molecules such as p38 MAPK, NF-KB, and AP-1. Nrf2 subsequently functions to inhibit the production of pro-inflammatory mediators including cytokines, chemokines, cell adhesion molecules, matrix metalloprotein-ases, COX-2 and iNOS. Although not clearly elucidated, the antioxidative function of genes targeted by Nrf2 may cooperatively regulate the innate immune response and also repress the expression of proinflammatory mediators.

PCI-24781 induces caspase and reactive oxygen species-dependent apoptosis through NF-kappaB mechanisms and is synergistic with bortezomib in lymphoma cells

PURPOSE

We investigated the cytotoxicity and mechanisms of cell death of the broad-spectrum histone deacetylase (HDAC) inhibitor PCI-24781, alone and combined with bortezomib in Hodgkin lymphoma and non-Hodgkin lymphoma cell lines and primary lymphoproliferative (CLL/SLL) cells.

EXPERIMENTAL DESIGN

Apoptosis, mitochondrial membrane potential, cell cycle analysis, and reactive oxygen species (ROS) were measured by flow cytometry, whereas caspase activation was determined by Western blot. Nuclear factor kappaB (NF-kappaB)-related mRNAs were quantified by reverse transcription-PCR, NF-kappaB-related proteins by Western blotting, and NF-kappaB DNA-binding activity by electromobility shift assay. Finally, gene expression profiling was analyzed.

RESULTS

PCI-24781 induced concentration-dependent apoptosis that was associated with prominent G(0)/G(1) arrest, decreased S-phase, increased p21 protein, and increased ROS in Hodgkin lymphoma and non-Hodgkin lymphoma cell lines. Dose-dependent apoptosis with PCI-24781 was also seen among primary CLL/SLL cells. PCI-24781-induced apoptosis was shown to be ROS- and caspase-dependent. Combined PCI-24781/bortezomib treatment resulted in strong synergistic apoptosis in all non-Hodgkin lymphoma lines (combination indices, 0.19-0.6) and was additive in Hodgkin lymphoma and primary CLL/SLL cells. Further, PCI-24781/bortezomib resulted in increased caspase cleavage, mitochondrial depolarization, and histone acetylation compared with either agent alone. Gene expression profiling showed that PCI-24781 alone significantly down-regulated several antioxidant genes, proteasome components, and NF-kappaB pathway genes, effects that were enhanced further with bortezomib. Reverse transcription-PCR confirmed down-regulation of NF-kappaB1 (p105), c-Myc, and IkappaB-kinase subunits, where NF-kappaB DNA binding activity was decreased.

CONCLUSION

We show that PCI-24781 results in increased ROS and NF-kappaB inhibition, leading to caspase-dependent apoptosis. We also show that bortezomib is synergistic with PCI-24781. This combination or PCI-24781 alone has potential therapeutic value in lymphoma.

YS 49, 1-(alpha-naphtylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, regulates angiotensin II-stimulated ROS production, JNK phosphorylation and vascular smooth muscle cell proliferation via the induction of heme oxygenase-1

Overexpression of the gene for heme oxygenase (HO)-1 leads to a reduction in pressor responsiveness to angiotensin II (Ang II) in experimental animals. Using rat vascular smooth muscle cells (VSMCs), we tested whether YS 49 [1-(alpha-naphtylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline] inhibits Ang II-stimulated proliferation of VSMCs via induction of HO-1. YS 49 induced HO-1 protein production in a dose-and time-dependent manner in VSMCs. Treatment with YS 49 significantly and dose-dependently inhibited Ang II-induced VSMC proliferation, ROS production, and phosphorylation of JNK, but not P38 MAP kinase or ERK1/2. The antiproliferation effect of YS 49 was reversed by pretreatment with the HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX), or with hemoglobin, a carbon monoxide (CO) scavenger. Similarly, VSMC proliferation, ROS production and phosphorylation of JNK by Ang II were significantly inhibited in VSMCs transfected with the HO-1 gene. Thus, HO-1 and the HO-1 product CO play, at least in part, a crucial role in Ang II-stimulated VSMC proliferation through the regulation of ROS production and JNK phosphorylation. Therefore, YS 49 has potential as a therapeutic strategy for the pathogenesis of Ang II-related vascular diseases such as hypertension and atherosclerosis, via the induction of HO-1 gene activity.