Antagonism of cysteinyl leukotriene receptor 1 (cysLTR1) by montelukast suppresses cell senescence of chondrocytes

SIRT3 Activation a Promise in Drug Development? New Insights into SIRT3 Biology and Its Implications on the Drug Discovery Process

Sirtuins catalyze deacetylation of lysine residues with a NAD+-dependent mechanism. In mammals, the sirtuin family is composed of seven members, divided into four subclasses that differ in substrate specificity, subcellular localization, regulation, as well as interactions with other proteins, both within and outside the epigenetic field. Recently, much interest has been growing in SIRT3, which is mainly involved in regulating mitochondrial metabolism. Moreover, SIRT3 seems to be protective in diseases such as age-related, neurodegenerative, liver, kidney, heart, and metabolic ones, as well as in cancer. In most cases, activating SIRT3 could be a promising strategy to tackle these health problems. Here, we summarize the main biological functions, substrates, and interactors of SIRT3, as well as several molecules reported in the literature that are able to modulate SIRT3 activity. Among the activators, some derive from natural products, others from library screening, and others from the classical medicinal chemistry approach.

P53: A Key Target in the Development of Osteoarthritis

Osteoarthritis (OA), a chronic degenerative disease characterized mainly by damage to the articular cartilage, is increasingly relevant to the pathological processes of senescence, apoptosis, autophagy, proliferation, and differentiation of chondrocytes. Clinical strategies for osteoarthritis can only improve symptoms and even along with side effects due to age, sex, disease, and other factors. Therefore, there is an urgent need to identify new ideas and targets for current clinical treatment. The tumor suppressor gene p53, which has been identified as a potential target for tumor therapeutic intervention, is responsible for the direct induction of the pathological processes involved in OA modulation. Consequently, deciphering the characteristics of p53 in chondrocytes is essential for investigating OA pathogenesis due to p53 regulation in an array of signaling pathways. This review highlights the effects of p53 on senescence, apoptosis, and autophagy of chondrocytes and its role in the development of OA. It also elucidates the underlying mechanism of p53 regulation in OA, which may help provide a novel strategies for the clinical treatment of OA.

Potential Mechanisms Underlying the Therapeutic Roles of Gancao fuzi Decoction in Cold-dampness Obstruction Syndrome-type Knee Osteoarthritis

BACKGROUND

The key active components and potential molecular mechanism of Gancao Fuzi decoction (GFD) in the treatment of cold-dampness obstruction-type knee osteoarthritis (KOA) remain unclear.

OBJECTIVES

To explore the mechanism of GFD in the treatment of cold-dampness obstruction syndrome-type KOA by network pharmacology.

METHODS

The potential active components and targets of the four herbs in GFD (Fuzi, Guizhi, Baizhu, and Gancao) were screened using the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. The targets of KOA were obtained with the Comparative Toxicogenomics Database (CTD), the GeneCards database, and the DisGeNET database, and the common targets of the drugs and disease were ultimately obtained. Cytoscape (v.3.7.1) was used to draw the active component-target network, and the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) (v.11.0) database was used to construct the protein interaction network. The Database for Annotation, Visualization, and Integrated Discovery (DAVID) was used for the Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the intersecting targets.

RESULTS

A total of 102 potential active components and 208 targets of GFD in the treatment of cold-dampness obstruction syndrome-type KOA were screened. GFD treatment was found to be closely related to many inflammatory signalling pathways in the treatment of KOA.

CONCLUSION

The effect of GFD on cold-dampness obstruction syndrome-type KOA is mediated by multicomponent, multitarget, and multichannel mechanisms, which provides the basis for further experimental study of its pharmacodynamic material basis and mechanism.

The role of cellular senescence in skin aging and age-related skin pathologies

Aging is the result of a gradual functional decline at the cellular, and ultimately, organismal level, resulting in an increased risk of developing a variety of chronic illnesses, such as cardiovascular disease, stroke, cancer and diabetes. The skin is the largest organ of the human body, and the site where signs of aging are most visible. These signs include thin and dry skin, sagging, loss of elasticity, wrinkles, as well as aberrant pigmentation. The appearance of these features is accelerated by exposure to extrinsic factors such as ultraviolet (UV) radiation or pollution, as well as intrinsic factors including time, genetics, and hormonal changes. At the cellular level, aging is associated with impaired proteostasis and an accumulation of macromolecular damage, genomic instability, chromatin reorganization, telomere shortening, remodelling of the nuclear lamina, proliferation defects and premature senescence. Cellular senescence is a state of permanent growth arrest and a key hallmark of aging in many tissues. Due to their inability to proliferate, senescent cells no longer contribute to tissue repair or regeneration. Moreover, senescent cells impair tissue homeostasis, promote inflammation and extracellular matrix (ECM) degradation by secreting molecules collectively known as the "senescence-associated secretory phenotype" (SASP). Senescence can be triggered by a number of different stimuli such as telomere shortening, oncogene expression, or persistent activation of DNA damage checkpoints. As a result, these cells accumulate in aging tissues, including human skin. In this review, we focus on the role of cellular senescence during skin aging and the development of age-related skin pathologies, and discuss potential strategies to rejuvenate aged skin.

Montelukast induces beneficial behavioral outcomes and reduces inflammation in male and female rats

Background

Accumulative data links inflammation and immune dysregulation to the pathophysiology of mental disorders; little is known regarding leukotrienes’ (LTs) involvement in this process. Circumstantial evidence suggests that treatment with leukotriene modifying agents (LTMAs) such as montelukast (MTK) may induce adverse neuropsychiatric events. Further methodic evaluation is warranted.

Objective

This study aims to examine behavioral effects, as well as inflammatory mediator levels of chronic MTK treatment in male and female rats.

Methods

Depression-like phenotypes were induced by exposing male and female rats to a chronic unpredictable mild stress (CUMS) protocol for four weeks. Thereafter, rats were treated (intraperitoneally) once daily, for two weeks, with either vehicle (dimethyl sulfoxide 0.2 ml/rat) or 20 mg/kg MTK. Following treatment protocols, behavioral tests were conducted and brain regions were evaluated for inflammatory mediators including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and prostaglandin (PG) E2.

Results

Overall, MTK did not invoke negative behavioral phenotypes (except for an aggression-inducing effect in males). Numerous positive behavioral outcomes were observed, including reduction in aggressive behavior in females and reduced manic/hyperactive-like behavior and increased sucrose consumption (suggestive of antidepressant-like effect) in males. Furthermore, in control males, MTK increased IL-6 levels in the hypothalamus and TNF-α in the frontal cortex, while in control females it generated a robust anti-inflammatory effect. In females that were subjected to CUMS, MTK caused a prominent reduction in TNF-α and IL-6 in brain regions, whereas in CUMS-subjected males its effects were inconsistent.

Conclusion

Contrary to prior postulations, MTK may be associated with select beneficial behavioral outcomes. Additionally, MTK differentially affects male vs. female rats in respect to brain inflammatory mediators, plausibly explaining the dissimilar behavioral phenotypes of sexes under MTK treatment.

Lipids as Regulators of Cellular Senescence

Lipids are key macromolecules that perform a multitude of biological functions ranging from maintaining structural integrity of membranes, energy storage, to signaling molecules. Unsurprisingly, variations in lipid composition and its levels can influence the functional and physiological state of the cell and its milieu. Cellular senescence is a permanent state of cell cycle arrest and is a hallmark of the aging process, as well as several age-related pathologies. Senescent cells are often characterized by alterations in morphology, metabolism, chromatin remodeling and exhibit a complex pro-inflammatory secretome (SASP). Recent studies have shown that the regulation of specific lipid species play a critical role in senescence. Indeed, some lipid species even contribute to the low-grade inflammation associated with SASP. Many protein regulators of senescence have been well characterized and are associated with lipid metabolism. However, the link between critical regulators of cellular senescence and senescence-associated lipid changes is yet to be elucidated. Here we systematically review the current knowledge on lipid metabolism and dynamics of cellular lipid content during senescence. We focus on the roles of major players of senescence in regulating lipid metabolism. Finally, we explore the future prospects of lipid research in senescence and its potential to be targeted as senotherapeutics.

MOntelukast as a potential CHondroprotective treatment following Anterior cruciate ligament reconstruction (MOCHA Trial): study protocol for a double-blind, randomized, placebo-controlled clinical trial

BACKGROUND

After anterior cruciate ligament (ACL) reconstruction, patient-reported outcomes are improved 10 years post-surgery; however, cytokine concentrations remain elevated years after surgery with over 80% of those with combined ACL and meniscus injuries having posttraumatic osteoarthritis (PTOA) within 10-15 years. The purpose of this multicenter, randomized, placebo-controlled trial is to assess whether a 6-month course of oral montelukast after ACL reconstruction reduces systemic markers of inflammation and biochemical and imaging biomarkers of cartilage degradation.

METHODS

We will enroll 30 individuals undergoing primary ACL reconstruction to participate in this IRB-approved multicenter clinical trial. This trial will target those at greatest risk of a more rapid PTOA onset (age range 25-50 with concomitant meniscus injury). Patients will be randomly assigned to a group instructed to take 10 mg of montelukast daily for 6 months following ACL reconstruction or placebo. Patients will be assessed prior to surgery and 1, 6, and 12 months following surgery. To determine if montelukast alters systemic inflammation following surgery, we will compare systemic concentrations of prostaglandin E2, monocyte chemoattractant protein-1, and pro-inflammatory cytokines between groups. We will also compare degradative changes on magnetic resonance imaging (MRI) collected 1 and 12 months following surgery between groups with reductions in early biomarkers of cartilage degradation assessed with urinary biomarkers of type II collagen breakdown and bony remodeling.

DISCUSSION

There is a complex interplay between the pro-inflammatory intra-articular environment, underlying bone remodeling, and progressive cartilage degradation. PTOA affects multiple tissues and appears to be more similar to rheumatoid arthritis than osteoarthritis with respect to inflammation. There is currently no treatment to delay or prevent PTOA after ACL injury. Since there is a larger and more persistent inflammatory response after ACL reconstruction than the initial insult of injury, treatment may need to be initiated after surgery, sustained over a period of time, and target multiple mechanisms in order to successfully alter the disease process. This study will assess whether a 6-month postoperative course of oral montelukast affects multiple PTOA mechanisms. Because montelukast administration can be safely sustained for long durations and offers a low-cost treatment option, should it be proven effective in the current trial, these results can be immediately incorporated into clinical practice.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04572256 . Registered on October 1, 2020.

Montelukast attenuates interleukin IL-1β-induced oxidative stress and apoptosis in chondrocytes by inhibiting CYSLTR1 (Cysteinyl Leukotriene Receptor 1) and activating KLF2 (Kruppel Like Factor 2)

Montelukast is a cysteinyl leukotriene receptor 1 (CysLTR1) antagonist widely used to suppress the inflammatory response in asthma and allergic rhinitis. This study aimed to investigate the potential impacts of montelukast on osteoarthritis (OA) progression. To determine the role of montelukast in OA, the expression of CysLTR1 was first examined by quantitative reverse transcription PCR (RT-qPCR) and western blot in IL-1β-induced ATDC5 cells treated with or without montelukast. Subsequently, the impacts of montelukast on cell viability and oxidative stress were measured by Cell-Counting-Kit-8 (CCK-8), commercial kits and western blot. Oxidative stress-related protein expressions were determined by western blot analysis in Il-1β-induced ATDC5 cells. Cell apoptosis and cartilage degradation were examined by TdT-mediated dUTP Nick-End Labeling (TUNEL) assay, western blot and RT-qPCR. KLF2 expression was measured in IL-1β-induced ATDC5 cells treated with montelukast. After interference with small interfering RNA (siRNA)-KLF2 in ATDC5 cells, the loss-of-function assays were also performed in same ways. CysLTR1 expression was elevated in IL-1β-induced ATDC5 cells but inhibited significantly by montelukast. Montelukast attenuated the oxidative stress and apoptosis, improved cell viability. Moreover, montelukast enhanced KLF2 expression. After transfected with siRNA-KLF2, montelukast attenuated cell injury, oxidative stress, apoptosis and cartilage degradation in IL-1β-induced ATDC5 cells by activating KLF2.In summary, this work elaborates the evidence that montelukast could attenuate oxidative stress and apoptosis in IL-1β-induced chondrocytes by inhibiting CysLTR1 and activating KLF2, which can guide the therapeutic strategies of montelukast for OA development in the future.

Feprazone Mitigates IL-1β-Induced Cellular Senescence in Chondrocytes

The proinflammatory cytokine interleukin-1 β (IL-1β)-mediated cellular senescence in chondrocytes is involved in the development and pathological progression of osteoarthritis (OA). Feprazone, a nonsteroidal anti-inflammatory drug (NSAID) and a cyclooxygenase (COX) inhibitor, is widely used in clinics. This study aims to investigate whether Feprazone has a protective effect against IL-1β-induced cellular senescence in human chondrocytes. In this study, C-28/I2 chondrocytes were stimulated with IL-1β (10 ng/mL) in the presence or absence of Feprazone (10 and 20 μM). Cellular senescence was assessed using senescence-associated β-galactosidase (SA-β-Gal) staining. The cell cycle was examined using flow cytometry. Gene and protein expressions were determined with real-time polymerase chain reaction (PCR) and western blot analysis. We found that treatment with Feprazone ameliorated IL-1β-induced increase in cellular senescence. Feprazone increased telomerase activity and prevented cell cycle arrest in the G0/G1 phase. We also found that Feprazone reduced the expressions of plasminogen activator inhibitor-1 (PAI-1) and p21, two important regulators of cellular senescence. Additionally, treatment with Feprazone reduced the expressions of matrix metalloprotein (MMP-13) and a disintegrin-like and metalloproteinase with thrombospondin type-1 motif-5 (ADAMTS-5). Interestingly, Feprazone prevented the activation of nuclear factor kappa-B (NF-κB) by preventing nuclear translocation of NF-κB p65 and the luciferase activity of the NF-κB promoter. The results also show that Feprazone increased nuclear levels of nuclear factor erythroid 2-related factor-2 (Nrf2) and reduced the production of reactive oxygen species (ROS). Importantly, silencing of Nrf2 abolished the protective effects of Feprazone against IL-1β-induced NF-κB activation and cellular senescence. These findings shed light on the potential use of Feprazone in the treatment of OA based on a novel mechanism.

Salicin prevents TNF-α-induced cellular senescence in human umbilical vein endothelial cells (HUVECs)

Cellular senescence is strongly tied to vascular disease. The current study aims to examine ways that endothelial cellular senescence can be prevented and the mechanisms by which prevention of senescence occurs. Human umbilical vein endothelial cells were exposed to TNF-α to induce senescence; then salicin was administered in two doses - 50 and 100 µM - to establish a dose-dependent effect of salicin on SA-β-Gal, G1 cell cycle arrest, expression of p21 and PAI-1, p53 acetylation at K382, NRF2 and oxidative stress. NRF2 was examined as a mediating mechanism of salicin's impact on cellular senescence and was found to account for salicin's impact on SA-β-Gal, p21, PAI-1 and p53. Together, these results provide a compelling case that salicin has a substantial impact on numerous factors tied to cellular senescence in human endothelial cells. Thus, treatment with salicin may hold promise as a means of preventing aging-related vascular disease. Furthermore, salicin appears to operate via a functional pathway that is different from that affected by anti-inflammatory drugs (e.g. aspirin).

Protective effect of vildagliptin on TNF-α-induced chondrocyte senescence

Osteoarthritis (OA) is a common age-related disorder. Chondrocytes in joint tissue play a critical role in normal articular cartilage function and tissue homeostasis. Local inflammatory cytokine-induced chondrocyte senescence contributes to the development and progression of OA. Various dipeptidyl peptidase-4 (DPP-4) inhibitors have been widely used to treat type 2 diabetes. Here, we report a novel pharmacological role of the DPP-4 inhibitor vildagliptin in chondrocyte senescence. Our data indicate that DPP-4 is an inducible factor responsive to tumor necrosis factor-α (TNF-α) treatment in chondrocytes. The inhibition of DPP-4 by vildagliptin ameliorates TNF-α-induced chondrocyte senescence as determined by cellular senescence-associated β-galactosidase (SA-β-Gal) activity. Vildagliptin displayed protective capabilities against TNF-α-induced chondrocyte cell cycle arrest in the G1 phase. Moreover, vildagliptin suppresses the three major TNF-α-induced chondrocyte senescence proteins including p53, p21, and plasminogen activator inhibitor-1 (PAI-1). Vildagliptin also suppresses TNF-α-induced p53 acetylation at K382. Consistently, our findings demonstrate the inhibitory effect of vildagliptin on p53 acetylation, which is mediated by sirtuin 1 (SIRT1) as the inhibition of SIRT1 negated the inhibitory action of vildagliptin on p53 acetylation. Furthermore, we found that the effect of vildagliptin on SIRT1 protection is adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) dependent, and the inhibition of AMPK activity negated the protection of vildagliptin against SIRT1 and chondrocytes senescence. In conclusion, our study explored the molecular mechanism and protective effect of the antidiabetic drug vildagliptin against chondrocyte senescence, and our findings imply that vildagliptin has a therapeutic potential in OA. © 2019 IUBMB Life, 1-2, 2019.

The senescence-associated secretory phenotype and its regulation

The senescence-associated secretory phenotype (SASP) defines the ability of senescent cells to express and secrete a variety of extracellular modulators that includes cytokines, chemokines, proteases, growth factors and bioactive lipids. The role of the SASP depends on the context. The SASP reinforces the senescent cell cycle arrest, stimulates the immune-mediated clearance of potentially tumorigenic cells, limits fibrosis and promotes wound healing and tissue regeneration. On the other hand, the SASP can mediate chronic inflammation and stimulate the growth and survival of tumor cells. The regulation of the SASP occurs at multiple levels including chromatin remodelling, activation of specific transcription factors such as C/EBP and NF-κB, control of mRNA translation and intracellular trafficking. Several SASP modulators have already been identified setting the stage for future research on their clinical applications.

[Association of cytoplasmic phospholipase A2 gene polymorphism with bronchial asthma and response to montelukast in children]

OBJECTIVE

To study the association of cytoplasmic phospholipase A2 (PLA2G4) rs932476 polymorphism with the development of bronchial asthma and the response to montelukast, a leukotriene receptor antagonist, in children.

METHODS

A total of 128 children with bronchial asthma were enrolled as case group, and 100 healthy children were enrolled as control group. The genotype and allele frequencies of PLA2G4 rs932476 were compared between the two groups. The children in the case group were administered with montelukast except routine treatment for 2 months, and the changes in serum levels of leukotriene B4 (LTB4), interleukin-4 (IL-4), immunoglobulin E (IgE), and interferon gamma (IFN-γ), pulmonary function and fractional exhaled nitric oxide (FeNO) after treatment were observed.

RESULTS

There were no significant differences in the genotype and allele frequencies of PLA2G4 rs932476 between the case and control groups, as well as between the groups with different severities of asthma (P>0.05). After treatment, the children with AA genotype had a significantly higher overall response rate than those with GG genotype. After treatment, the case group had significant reductions in the serum levels of IgE and IL-4 and a significant increase in the level of IFN-γ (P<0.05). After treatment, the children with GG genotype had a higher serum level of IL-4 and a lower level of IFN-γ than those with AA genotype. After treatment, the case group had significant increases in pulmonary function parameters, and the children with AA genotype had significantly higher parameters than those with GG genotype. The case group had a significant reduction in the level of FeNO, and the children with AA genotype had a significantly lower level than those with GG genotype after treatment. The case group had a significantly higher serum level of LTB4 than the control group before treatment (P<0.05). After treatment the case group had a significant reduction in the serum level of LTB4 (P<0.05). The children with GG genotype had a significantly higher level of LTB4 than those with AA genotype after treatment (P<0.05).

CONCLUSIONS

PLA2G4 rs932476 polymorphism is not associated with the susceptibility and severity of bronchial asthma in children, but it may has certain influence on children's response to the leukotriene receptor antagonist montelukast, possibly by affecting the level of LTB4.

SIRT3 Activation by Dihydromyricetin Suppresses Chondrocytes Degeneration via Maintaining Mitochondrial Homeostasis

Mitochondrial dysfunction is an important contributor to the development of osteoarthritis (OA). Sirtuin 3 (SIRT3) regulates diverse mitochondrial proteins to maintain mitochondrial homeostasis, and dihydromyricetin (DHM) is reported as a potential SIRT3 activator. This study aims to explore the relevance of SIRT3 and OA, as well as the therapeutic effects of DHM on mitochondrial homeostasis in TNF-α-treated chondrocytes. The relationship between SIRT3 and OA was confirmed by detecting SIRT3 level in vitro and in vivo. Mitochondrial dysfunction was evaluated in chondrocytes with or without SIRT3 knockdown. Furthermore, the effects of DHM on mitochondrial homeostasis were performed in TNF-α-treated rat chondrocytes in vitro. In this study, our results showed that the SIRT3 level was decreased in mouse OA cartilage, corresponding to the reduced SIRT3 level in TNF-α-treated chondrocytes in vitro. SIRT3 knockdown induced mitochondrial dysfunction in chondrocytes. Moreover, our study demonstrated that DHM might activate SIRT3 to protect rat chondrocytes from TNF-α-induced degeneration and protective effects of DHM on mitochondrial homeostasis in chondrocytes attributed to enhanced SIRT3. Collectively, SIRT3 deficiency is implicated in OA development and DHM exerts anti-degeneration effect by maintaining mitochondrial homeostasis via a SIRT3-dependent manner in chondrocytes.

Montelukast attenuates rotenone-induced microglial activation/p38 MAPK expression in rats: Possible role of its antioxidant, anti-inflammatory and antiapoptotic effects

Montelukast (MK),a cysteinyl leukotriene (CysLT1) receptor antagonist, latterly exhibited a remarkable neuroprotective activity in various neurodegenerative disorders. This study aims to elucidate the neuroprotective effect of MK in rotenone-induced Parkinson's disease(PD) model in rats. Ninety six male rats were split into four groups: vehicle control (0.2 ml/kg/48 h, sc), MK (10 mg/kg/day, ip), rotenone (1.5 mg/kg/48 h, sc.) and rotenone pretreated with MK. Rotenone treatment led to significant reduction in motor functioning and elevation in oxidative stress markers. Additionally, upregulation of p38 mitogen-activated protein kinase (p38 MAPK) and CysLT1 receptor expressions were anchored with enhanced striatal microglial activation generating a severe neuro-inflammatory milieu. Furthermore, an augmentation in p53 expression and cleaved caspases-3 activity increased apoptotic neurodegeneration synchronized with reduction of striatal tyrosine hydroxylase (TH) content. Changes in neuronal morphology was also noted. MK administration significantly mitigated motor impairment and rise in oxidative stress mediators. As well, the anti-inflammatory activity of MK was manifested by hindering the principal controller of inflammatory pathway, nuclear factor-kappa B, followed by its downstream pro-inflammatory cytokines (tumor necrosis factor-alpha and interleukin-1 beta), by attenuating striatal microglial activation and hampering the expression of both p38 MAPK and CysLT1. Moreover, MK revealed a decline in p53 expression with its downstream cleaved caspases-3 which resulted in preservation of striatal TH terminals as verified by increased striatal TH content and improvement in the histopathological changes incited by rotenone. In conclusion, MK endowed neuroprotective effects in rotenone-induced PD animal model via attenuation of microglial cell activation and p38 MAPK expression.

Role of the Inflammation-Autophagy-Senescence Integrative Network in Osteoarthritis

Osteoarthritis is the most common musculoskeletal disease causing chronic disability in adults. Studying cartilage aging, chondrocyte senescence, inflammation, and autophagy mechanisms have identified promising targets and pathways with clinical translatability potential. In this review, we highlight the most recent mechanistic and therapeutic preclinical models of aging with particular relevance in the context of articular cartilage and OA. Evidence supporting the role of metabolism, nuclear receptors and transcription factors, cell senescence, and circadian rhythms in the development of musculoskeletal system degeneration assure further translational efforts. This information might be useful not only to propose hypothesis and advanced models to study the molecular mechanisms underlying joint degeneration, but also to translate our knowledge into novel disease-modifying therapies for OA.