DPIE [2-(1,2-diphenyl-1H-indol-3-yl)ethanamine] Augments Pro-Inflammatory Cytokine Production in IL-1β-Stimulated Primary Human Oral Cells

Clustering human dental pulp fibroblasts spontaneously activate NLRP3 and AIM2 inflammasomes and induce IL-1β secretion

Objectives

The objective of the present study was to investigate whether NOD-like receptor family pyrin domain-containing 3 (NLRP3) and absent in melanoma 2 (AIM2) inflammasomes pathways were involved in an experimental model of fibroblast activation named nemosis, which was used to mimic circumstances without bacteria stimulation.

Methods

Nemosis of human dental pulp fibroblast (DPFs) was induced by three-dimensional culture in U-shaped 96-well plates and investigated by scanning electron microscopy (SEM). DPFs monolayers were used as control. Annexin V-FITC/7-AAD apoptosis assay was performed on the DPFs spheroids by flowcytometry. Caspase-1 activity detection assay was conducted on the DPFs spheroids. Quantitative real-time polymerase chain reaction (qRT-PCR), cytokine measurements, Western blot and the effect of COX-2 inhibitor on spheroids was studied.

Results

SEM study observed human dental pulp fibroblast clusters and cell membranes damage on the surface of DPFs spheroids. The percentages of necrotic cells from DPFs spheroids gradually increased as the incubation time increased. A statistically significant increase in caspase-1 activity was observed after DPFs spheroids formation. DPFs spheroids displayed significant amounts of NLRP3, AIM2 mRNA and protein expression, caspase-1 mRNA expression and cleaved Caspase-1 protein expression and high IL-1β concentrations (P < 0.05) than DPFs monolayers. Specific COX-2 inhibitor (NS-398) decreased NLRP3 mRNA and protein expression, cleaved Caspase-1 protein expression, Caspase-1 activity and IL-1β mRNA expression and IL-1β concentrations (P < 0.05). However, Specific COX-2 inhibitor had no impact on AIM2 mRNA and protein expression, caspase-1 mRNA expression and pro-Caspase-1 protein expression.

Conclusions

In conclusion, clustering human DPFs spontaneously activated NLRP3 and AIM2 inflammasomes and induced IL-1β secretion which could be partially attenuated by COX-2 inhibitor. Thus, nemosis could become a powerful model for studying mechanisms underlying aseptic pulpitis.

The Therapeutic Prospects of Targeting IL-1R1 for the Modulation of Neuroinflammation in Central Nervous System Disorders

The interleukin-1 receptor type 1 (IL-1R1) holds pivotal roles in the immune system, as it is positioned at the “epicenter” of the inflammatory signaling networks. Increased levels of the cytokine IL-1 are a recognized feature of the immune response in the central nervous system (CNS) during injury and disease, i.e., neuroinflammation. Despite IL-1/IL-1R1 signaling within the CNS having been the subject of several studies, the roles of IL-1R1 in the CNS cellular milieu still cause controversy. Without much doubt, however, the persistent activation of the IL-1/IL-1R1 signaling pathway is intimately linked with the pathogenesis of a plethora of CNS disease states, ranging from Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS), all the way to schizophrenia and prion diseases. Importantly, a growing body of evidence is showing that blocking IL-1R1 signaling via pharmacological or genetic means in different experimental models of said CNS diseases leads to reduced neuroinflammation and delayed disease progression. The aim of this paper is to review the recent progress in the study of the biological roles of IL-1R1, as well as to highlight key aspects that render IL-1R1 a promising target for the development of novel disease-modifying treatments for multiple CNS indications.

Synthesis of DPIE [2-(1,2-Diphenyl-1H-indol-3-yl)ethanamine] Derivatives and Their Regulatory Effects on Pro-Inflammatory Cytokine Production in IL-1β-Stimulated Primary Human Oral Cells

Interleukin-1 beta (IL-1β) has diverse physiological functions and plays important roles in health and disease. In this report, we focus on its function in the production of pro-inflammatory cytokines, including IL-6 and IL-8, which are implicated in several autoimmune diseases and host defense against infection. IL-1β activity is markedly dependent on the binding affinity toward IL-1 receptors (IL-1Rs). Several studies have been conducted to identify suitable small molecules that can modulate the interactions between 1L-1β and 1L-1R1. Based on our previous report, where DPIE [2-(1,2-Diphenyl-1H-indol-3-yl)ethanamine] exhibited such modulatory activity, three types of DPIE derivatives were synthesized by introducing various substituents at the 1, 2, and 3 positions of the indole group in DPIE. To predict a possible binding pose in complex with IL-1R1, a docking simulation was performed. The effect of the chemicals was determined in human gingival fibroblasts (GFs) following IL-1β induction. The DPIE derivatives affected different aspects of cytokine production. Further, a group of the derivatives enabled synergistic pro-inflammatory cytokine production, while another group caused diminished cytokine production compared to DPIE stimulation. Some groups displayed no significant difference after stimulation. These findings indicate that the modification of the indole site could modulate IL-1β:IL1R1 binding affinity to reduce or enhance pro-inflammatory cytokine production.

Comprehensive Pan-Cancer Analyses of Pyroptosis-Related Genes to Predict Survival and Immunotherapeutic Outcome

Simple Summary

Pyroptosis is a type of programmed cell death accompanied by inflammation. Although the dysregulation of pyroptosis has been reported to be involved in carcinogenesis, its function in cancer progression and therapy remains largely unknown and controversial because of the inconsistency across different cancer types. This study provides the most complete gene set of pyroptosis-related genes (PRGs), depicts their expression changes across 31 cancer types for the first time, and constructs a novel prognostic risk model to predict cancer patient survival. In addition, the effects of pyroptosis on immune cell infiltration and immunotherapy were dissected at the pan-cancer level. Small-molecule compounds, which may be beneficial to immunotherapy, were screened on the basis of differentially expressed PRGs. These results lay the foundation for the study of pyroptosis in cancer.

Abstract

Pyroptosis is a newly characterized type of programmed cell death. However, its function in cancer progression and its response to treatments remain controversial. Here, we extensively and systematically compiled genes associated with pyroptosis, integrated multiomics data and clinical data across 31 cancer types from The Cancer Genome Atlas, and delineated the global alterations in PRGs at the transcriptional level. The underlying transcriptional regulations by copy number variation, miRNAs, and enhancers were elucidated by integrating data from the Genotype-Tissue Expression and International Cancer Genome Consortium. A prognostic risk model, based on the expression of PRGs across 31 cancer types, was constructed. To investigate the role of pyroptosis in immunotherapy, we found five PRGs associated with effectiveness by exploring the RNA-Seq data of patients with immunotherapy, and further identified two small-molecule compounds that are potentially beneficial for immunotherapy. For the first time, from a pyroptosis standpoint, this study establishes a novel strategy to predict cancer patient survival and immunotherapeutic outcomes.

Small molecule approaches to treat autoimmune and inflammatory diseases (Part III): Targeting cytokines and cytokine receptor complexes

Chronic and dysregulated cytokine signaling plays an important role in the pathogenic development of many autoimmune and inflammatory diseases. Despite intrinsic challenges in the disruption of interactions between cytokines and cytokine receptors, many first-in-class small-molecule inhibitors have been discovered over the past few years. The third part of the digest series presents recent progress in identifying such inhibitors and highlights the application of novel research tools in the fields of structural biology, computational analysis, screening methods, biophysical/biochemical assays and medicinal chemistry strategy.

N-[2-(4-Acetyl-1-Piperazinyl)Phenyl]-2-(3-Methylphenoxy)Acetamide (NAPMA) Inhibits Osteoclast Differentiation and Protects against Ovariectomy-Induced Osteoporosis

Osteoclasts are large, multinucleated cells responsible for bone resorption and are induced in response to the regulatory activity of receptor activator of nuclear factor-kappa B ligand (RANKL). Excessive osteoclast activity causes pathological bone loss and destruction. Many studies have investigated molecules that specifically inhibit osteoclast activity by blocking RANKL signaling or bone resorption. In recent years, we screened compounds from commercial libraries to identify molecules capable of inhibiting RANKL-induced osteoclast differentiation. Consequently, we reported some compounds that are effective at attenuating osteoclast activity. In this study, we found that N-[2-(4-acetyl-1-piperazinyl)phenyl]-2-(3-methylphenoxy)acetamide (NAPMA) significantly inhibited the formation of multinucleated tartrate-resistant acid phosphatase (TRAP)-positive cells from bone marrow-derived macrophages in a dose-dependent manner, without cytotoxic effects. NAPMA downregulated the expression of osteoclast-specific markers, such as c-Fos, NFATc1, DC-STAMP, cathepsin K, and MMP-9, at the transcript and protein levels. Accordingly, bone resorption and actin ring formation were decreased in response to NAPMA treatment. Furthermore, we demonstrated the protective effect of NAPMA against ovariectomy-induced bone loss using micro-CT and histological analysis. Collectively, the results showed that NAPMA inhibited osteoclast differentiation and attenuated bone resorption. It is thus a potential drug candidate for the treatment of osteoporosis and other bone diseases associated with excessive bone resorption.

Sulforaphane prevents chromium-induced lung injury in rats via activation of the Akt/GSK-3β/Fyn pathway

Chromium (Cr) is an internationally recognized carcinogenic hazard that causes serious pulmonary toxicity. However, Cr-induced pulmonary toxicity lacks effective treatment to date. Sulforaphane (SFN), a well-known organosulfur compound, has gained increasing attention because of its unique biological function. This study investigates if SFN could decrease K₂Cr₂O₇-induced pulmonary toxicity and a potential mechanism involved using a rat 35-day Cr-induced pulmonary toxicity model and the mouse alveolar type II epithelial cell line (MLE-12). The results showed that SFN prevented Cr-induced oxidative stress, histopathological lesions, inflammation, apoptosis, and changes in protein kinase B (Akt) and glycogen synthase kinase 3 beta (GSK-3β) levels in vivo and in vitro. However, SFN can not play the protective effect against K₂Cr₂O₇-induced cell injury after treating by an Akt-specific inhibitor (MK-2206 2HCl) in MLE-12 cells. Furthermore, SFN increased the expression of nuclear factor-E2-related factor-2 (Nrf2) phase II detoxification enzymes. Collectively, this study demonstrates that SFN prevents K₂Cr₂O₇-induced lung toxicity in rats through enhancing Nrf2-mediated exogenous antioxidant defenses via activation of the Akt/GSK-3β/Fyn signaling pathway. SFN may be a novel natural substance to cure Cr-induced lung toxicity.

Sulfur-containing amino acids in aged garlic extract inhibit inflammation in human gingival epithelial cells by suppressing intercellular adhesion molecule-1 expression and IL-6 secretion

Aged garlic extract (AGE) contains various biologically active sulfur-containing amino acids, such as S-allylcysteine (SAC), S-1-propenylcysteine (S1PC) and S-allylmercaptocysteine (SAMC). These amino acids have been demonstrated to lower hypertension, improve atherosclerosis and enhance immunity through their anti-inflammatory and antioxidant activities. It was recently reported that the administration of AGE alleviated gingivitis in a clinical trial. In this study, to gain insight into this effect of AGE, the authors examined whether AGE and the three above-mentioned sulfur compounds influence the effects of tumor necrosis factor-α (TNF-α) in inducing intercellular adhesion molecule-1 (ICAM-1) expression and interleukin-6 (IL-6) secretion in Ca9-22 human gingival epithelial cells. It was found that S1PC reduced the level of ICAM-1 protein induced by TNF-α possibly through post-translational levels without affecting the TNF-α-induced mRNA expression. However, SAC and SAMC had no effect. It was also confirmed the inhibitory effect of an antimicrobial peptide [human-β defensin-3 (hβD3)] and found that the inhibitory effects of hbD3 and S1PC were synergistic. On the other hand, the TNF-α-induced IL-6 secretion was attenuated by SAC and SAMC in a dose-dependent manner, whereas S1PC was ineffective. In addition, SAC and SAMC, but not S1PC inhibited the phosphorylation of the transcription factor nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB), which is involved in the expression of inflammatory molecules, suggesting that the anti-inflammatory effects of SAC and SAMC are mediated, at least partly, by NF-κB. On the whole, the findings of this study suggest that the three sulfur amino acids in AGE function synergistically in alleviating inflammation in human gingival epithelial cells.

Inhibitory Effects of N-[2-(4-acetyl-1-piperazinyl) phenyl]-2-(2-chlorophenoxy) acetamide on Osteoclast Differentiation In Vitro via the Downregulation of TRAF6

Osteoclasts are poly-nuclear cells that resorb mineral components from old or damaged bone tissue. Primary mononuclear cells are activated by receptor activator of nuclear factor kappa-Β ligand (RANKL) and differentiate into large multinucleated cells. Dysregulation of osteoclast differentiation can lead to pathological bone loss and destruction. Many studies have focused on the development of new molecules to regulate RANKL-mediated signaling. In this study, N-[2-(4-acetyl-1-piperazinyl)phenyl]-2-(2-chlorophenoxy) acetamide (PPOA-N-Ac-2-Cl) led to a significant decrease in the formation of multinucleated tartrate-resistant acid phosphatase (TRAP)-positive cells in a dose-dependent manner, without inducing significant cytotoxicity. PPOA-N-Ac-2-Cl affected the expression of osteoclast-specific marker genes, such as TRAF6, c-fos, DC-STAMP, NFATc1, MMP9, CtsK, and TRAP (Acp5), during RANKL-mediated osteoclastogenesis. Moreover, PPOA-N-Ac-2-Cl significantly attenuated the protein levels of CtsK, a critical protease involved in bone resorption. Accordingly, bone resorption activity and F-actin ring formation decreased in the presence of PPOA-N-Ac-2-Cl. In conclusion, this study shows that PPOA-N-Ac-2-Cl acts as an inhibitor of osteoclast differentiation and may serve as a potential candidate agent for the treatment of osteoclast-related bone diseases by virtue of attenuating bone resorption.

The compromise of virtual screening and its impact on drug discovery

Introduction: Docking and structure-based virtual screening (VS) have been standard approaches in structure-based design for over two decades. However, our understanding of the limitations, potential, and strength of these techniques has enhanced, raising expectations. Areas covered: Based on a survey of reports in the past five years, we assess whether VS: (1) predicts binding poses in agreement with crystallographic data (when available); (2) is a superior screening tool, as often claimed; (3) is successful in identifying chemical scaffolds that can be starting points for subsequent lead optimization cycles. Data shows that knowledge of the target and its chemotypes in postprocessing lead to viable hits in early drug discovery endeavors. Expert opinion: VS is capable of accurate placements in the pocket for the most part, but does not consistently score screening collections accurately. What matters is capitalization on available resources to get closer to a viable lead or optimizable series. Integration of approaches, subjective hit selection guided by knowledge of the receptor or endogenous ligand, libraries driven by experimental guides, validation studies to identify the best docking/scoring that reproduces experimental findings, constraints regarding receptor-ligand interactions, thoroughly designed methodologies, and predefined cutoff scoring criteria strengthen VS's position in pharmaceutical research.

Inhibitory Effects of 2N1HIA (2-(3-(2-Fluoro-4-Methoxyphenyl)-6-Oxo-1(6H)-Pyridazinyl)-N-1H-Indol-5-Ylacetamide) on Osteoclast Differentiation via Suppressing Cathepsin K Expression

Osteoclasts are large multinucleated cells which are induced by the regulation of the receptor activator of nuclear factor kappa-Β ligand (RANKL), which is important in bone resorption. Excessive osteoclast differentiation can cause pathologic bone loss and destruction. Numerous studies have targeted molecules inhibiting RANKL signaling or bone resorption activity. In this study, 11 compounds from commercial libraries were examined for their effect on RANKL-induced osteoclast differentiation. Of these compounds, only 2-(3-(2-fluoro-4-methoxyphenyl)-6-oxo-1(6H)-pyridazinyl)-N-1H-indol-5-ylacetamide (2N1HIA) caused a significant decrease in multinucleated tartrate-resistant acid phosphatase (TRAP)-positive cell formation in a dose-dependent manner, without inducing cytotoxicity. The 2N1HIA compound neither affected the expression of osteoclast-specific gene markers such as TRAF6, NFATc1, RANK, OC-STAMP, and DC-STAMP, nor the RANKL signaling pathways, including p38, ERK, JNK, and NF-κB. However, 2N1HIA exhibited a significant impact on the expression levels of CD47 and cathepsin K, the early fusion marker and critical protease for bone resorption, respectively. The activity of matrix metalloprotease-9 (MMP-9) decreased due to 2N1HIA treatment. Accordingly, bone resorption activity and actin ring formation decreased in the presence of 2N1HIA. Taken together, 2N1HIA acts as an inhibitor of osteoclast differentiation by attenuating bone resorption activity and may serve as a potential candidate in preventing and/or treating osteoporosis, or other bone diseases associated with excessive bone resorption.

Litsea japonica Leaf Extract Suppresses Proinflammatory Cytokine Production in Periodontal Ligament Fibroblasts Stimulated with Oral Pathogenic Bacteria or Interleukin-1β

Periodontal disease, a chronic disease caused by bacterial infection, eventually progresses to severe inflammation and bone loss. Regulating excessive inflammation of inflamed periodontal tissues is critical in treating periodontal diseases. The periodontal ligament (PDL) is primarily a connective tissue attachment between the root and alveolar bone. PDL fibroblasts (PDLFs) produce pro-inflammatory cytokines in response to bacterial infection, which could further adversely affect the tissue and cause bone loss. In this study, we determined the ability of Litsea japonica leaf extract (LJLE) to inhibit pro-inflammatory cytokine production in PDLFs in response to various stimulants. First, we found that LJLE treatment reduced lipopolysaccharide (LPS)-induced pro-inflammatory cytokine (interleukin-6 and interleukin-8) mRNA and protein expression in PDLFs without cytotoxicity. Next, we observed the anti-inflammatory effect of LJLE in PDLFs after infection with various oral bacteria, including Fusobacterium nucleatum, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. These anti-inflammatory effects of LJLE were dose-dependent, and the extract was effective following both pretreatment and posttreatment. Moreover, we found that LJLE suppressed the effect of interleukin-1 beta-induced pro-inflammatory cytokine production in PDLFs. Taken together, these results indicate that LJLE has anti-inflammatory activity that could be exploited to prevent and treat human periodontitis by controlling inflammation.