A novel small-molecule tumor necrosis factor α inhibitor attenuates inflammation in a hepatitis mouse model

Decoy peptides that inhibit TNF signaling by disrupting the TNF homotrimeric oligomer

Tumor necrosis factor (TNF) is a pro-inflammatory cytokine and its functional homotrimeric form interacts with the TNF receptor (TNFR) to activate downstream apoptotic, necroptotic, and inflammatory signaling pathways. Excessive activation of these pathways leads to various inflammatory diseases, which makes TNF a promising therapeutic target. Here, 12-mer peptides were selected from the interface of TNF-TNFR based upon their relative binding energies and were named 'TNF-inhibiting decoys' (TIDs). These decoy peptides inhibited TNF-mediated secretion of cytokines and cell death, as well as activation of downstream signaling effectors. Effective TIDs inhibited TNF signaling by disrupting the formation of TNF's functional homotrimeric form. Among derivatives of TIDs, TID3c showed slightly better efficacy in cell-based assays by disrupting TNF trimer formation. Moreover, TID3c oligomerized TNF to a high molecular weight configuration. In silico modeling and simulations revealed that TID3c and its parent peptide, TID3, form a stable complex with TNF through hydrogen bonds and electrostatic interactions, which makes them the promising lead to develop peptide-based anti-TNF therapeutics.

CTRP13-Mediated Effects on Endothelial Cell Function and Their Potential Role in Obesity

BACKGROUND

Obesity, a major component of cardiometabolic syndrome, contributes to the imbalance between pro- and anti-atherosclerotic factors via dysregulation of adipocytokine secretion. Among these adipocytokines, the C1q/TNF-related proteins (CTRPs) play a role in the modulation of atherosclerosis development and progression. Here, we investigated the vascular effects of CTRP13.

RESULTS

CTRP13 is not only expressed in adipose tissue but also in vessels/endothelial cells (ECs) of mice, rats, and humans. Obese individuals (mice, rats, and humans) showed higher vascular CTRP13 expression. Human Umbilical Vein Endothelial Cells (HUVECs), cultured in the presence of serum from obese mice, mimicked this obesity-associated effect on CTRP13 protein expression. Similarly, high glucose conditions and TNF-alpha, but not insulin, resulted in a strong increase in CTRP13 in these cells. Recombinant CTRP13 induced a reduction in EC proliferation via AMPK. In addition, CTRP13 reduced cell cycle progression and increased p53 phosphorylation and p21 protein expression, but reduced Rb phosphorylation, with the effects largely depending on alpha-2 AMPK as suggested by adenoviral overexpression of dominant-negative (DN) or wild-type (WT) alpha 1/alpha 2 AMPK.

CONCLUSION

The present study demonstrates that CTRP13 expression is induced in ECs under diabetic conditions and that CTRP13 possesses significant vaso-modulatory properties which may have an impact on vascular disease progression in patients.

The Exacerbating Effects of the Tumor Necrosis Factor in Cardiovascular Stenosis: Intimal Hyperplasia

TNF-α functions as a master regulator of inflammation, and it plays a prominent role in several immunological diseases. By promoting important cellular mechanisms, such as cell proliferation, migration, and phenotype switch, TNF-α induces its exacerbating effects, which are the underlying cause of many proliferative diseases such as cancer and cardiovascular disease. TNF-α primarily alters the immune component of the disease, which subsequently affects normal functioning of the cells. Monoclonal antibodies and synthetic drugs that can target TNF-α and impair its effects have been developed and are currently used in the treatment of a few select human diseases. Vascular restenosis is a proliferative disorder that is initiated by immunological mechanisms. In this review, the role of TNF-α in exacerbating restenosis resulting from neointimal hyperplasia, as well as molecular mechanisms and cellular processes affected or induced by TNF-α, are discussed. As TNF-α-targeting drugs are currently not approved for the treatment of restenosis, the summation of the topics discussed here is anticipated to provide information that can emphasize on the use of TNF-α-targeting drug candidates to prevent vascular restenosis.

Discovery of the First-in-Class Inhibitors of Hypoxia Up-Regulated Protein 1 (HYOU1) Suppressing Pathogenic Fibroblast Activation

Fibroblasts are key regulators of inflammation, fibrosis, and cancer. Targeting their activation in these complex diseases has emerged as a novel strategy to restore tissue homeostasis. Here, we present a multidisciplinary lead discovery approach to identify and optimize small molecule inhibitors of pathogenic fibroblast activation. The study encompasses medicinal chemistry, molecular phenotyping assays, chemoproteomics, bulk RNA-sequencing analysis, target validation experiments, and chemical absorption, distribution, metabolism, excretion and toxicity (ADMET)/pharmacokinetic (PK)/in vivo evaluation. The parallel synthesis employed for the production of the new benzamide derivatives enabled us to a) pinpoint key structural elements of the scaffold that provide potent fibroblast-deactivating effects in cells, b) discriminate atoms or groups that favor or disfavor a desirable ADMET profile, and c) identify metabolic "hot spots". Furthermore, we report the discovery of the first-in-class inhibitor leads for hypoxia up-regulated protein 1 (HYOU1), a member of the heat shock protein 70 (HSP70) family often associated with cellular stress responses, particularly under hypoxic conditions. Targeting HYOU1 may therefore represent a potentially novel strategy to modulate fibroblast activation and treat chronic inflammatory and fibrotic disorders.

Photoaffinity labeling coupled with proteomics identify PDI-ADAM17 module is targeted by (-)-vinigrol to induce TNFR1 shedding and ameliorate rheumatoid arthritis in mice

Various biological agents have been developed to target tumor necrosis factor alpha (TNF-α) and its receptor TNFR1 for the rheumatoid arthritis (RA) treatment, whereas small molecules modulating such cytokine receptors are rarely reported in comparison to the biologicals. Here, by revealing the mechanism of action of vinigrol, a diterpenoid natural product, we show that inhibition of the protein disulfide isomerase (PDI, PDIA1) by small molecules activates A disintegrin and metalloprotease 17 (ADAM17) and then leads to the TNFR1 shedding on mouse and human cell membranes. This small-molecule-induced receptor shedding not only effectively blocks the inflammatory response caused by TNF-α in cells, but also reduces the arthritic score and joint damage in the collagen-induced arthritis mouse model. Our study indicates that targeting the PDI-ADAM17 signaling module to regulate the shedding of cytokine receptors by the chemical approach constitutes a promising strategy for alleviating RA.

Anti-inflammatory effects of TNF-α and ASK1 inhibitory compounds isolated from Schkuhria pinnata used for the treatment of dermatitis

ETHNO-PHARMACOLOGICAL RELEVANCE

The Andean Schkuhria pinnata species commonly known as 'Canchalagua' is used as an infusion in Andean countries to treat various anti-inflammatory and skin-related pathologies.

AIM OF THE STUDY

This study determined the anti-inflammatory activity of the aqueous extract from Schkuhria pinnata, identified compounds with high biological activity and performed a structure-activity relationship analysis to determine their binding mechanism.

MATERIALS AND METHODS

A bio-guided isolation of the active compounds of Schkuhria pinnata was carried out by selecting the most active sub-extracts and fractions to test their anti-inflammatory activity against the ASK1 and TNF-α cytokines.

RESULTS

Three compounds were obtained, and their structures were elucidated by nuclear magnetic resonance. The compounds were (3R,4R)-4-(3,4-dimethoxybenzyl)-3-(4-hydroxy-3-methoxybenzyl) dihydrofuran-2(3H)-one (1), N-[2,3-dihydro-1,3-dimethyl-6-[(2R)-2-methyl-1-piperazinyl]-2-oxo-1H-benzimidazol-5-yl]-2-methoxybenzamide (2), and N-hydroxy-1-cyclopentene-1-carboxamide (3). Regarding their anti-inflammatory activity, the three compounds inhibited the TNF-α and ASK1 cytokines, however, compound 2 was the most active, with an IC50 of 19.08 and 8.94 nM, respectively.

CONCLUSION

The anti-inflammatory activity of the aqueous extract of Schkuhria pinnata was evaluated, followed by the isolation of three compounds and the study of their pharmacological activity. The three compounds have been shown as promising treatment against dermatitis, confirming at the same time their traditional use.

Serum interα-trypsin inhibitor heavy chain H4 may be an anti-inflammatory marker reflecting disease risk, activity and treatment outcome of ankylosing spondylitis

Interα-trypsin inhibitor heavy chain H4 (ITIH4) modulates inflammation and immunity, which take part in the pathogenesis of ankylosing spondylitis (AS). The current research intended to discover the clinical value of serum ITIH4 quantification for AS management. Serum ITIH4 among 80 AS patients before current treatment initiation (baseline) at weeks (W) 4, 8 and 12 after treatment was detected by ELISA. Serum ITIH4 from 20 disease controls (DCs) and 20 healthy controls (HCs) was detected. ITIH4 expression was lower in AS patients than in DCs (p = 0.002) and HCs (p < 0.001). Among AS patients, ITIH4 was negatively associated with C-reactive protein (CRP) (r = -0.311, p = 0.005), bath AS disease activity index (BASDAI) (r = -0.223, p = 0.047), total pack pain (r = -0.273, p = 0.014) and AS disease activity score (ASDAS) (CRP) (r = -0.265, p = 0.018). Meanwhile, ITIH4 was negatively related to tumor necrosis factor (TNF)-α (r = -0.364, p = 0.001), interleukin (IL)-1β (r = -0.251, p = 0.025), IL-6 (r = -0.292, p = 0.009) and IL-17A (r = -0.254, p = 0.023). After treatment, the assessment of the spondylitis arthritis international society 40 response rate was 28.7% at W4, 46.3% at W8 and 55.0% at W12; ITIH4 showed an increasing trend from baseline to W12 (p < 0.001). Furthermore, ITIH4 at W8 (p = 0.020) and W12 (p = 0.035), but not at baseline or W4 (both p > 0.05), was enhanced in response patients vs. nonresponse patients. Additionally, ITIH4 at W12 was increased in AS patients receiving TNF inhibitors vs. those receiving nonsteroidal anti-inflammatory drugs (NSAIDs) (p = 0.024). Serum ITIH4 increases after treatment, and its augmentation is correlated with lower disease activity, decreased inflammation and enhanced treatment response in AS patients.

Cooperative NF-κB and Notch1 signaling promotes macrophage-mediated MenaINV expression in breast cancer

Metastasis is a multistep process that leads to the formation of clinically detectable tumor foci at distant organs and frequently to patient demise. Only a subpopulation of breast cancer cells within the primary tumor can disseminate systemically and cause metastasis. To disseminate, cancer cells must express MenaINV, an isoform of the actin regulatory protein Mena, encoded by the ENAH gene, that endows tumor cells with transendothelial migration activity, allowing them to enter and exit the blood circulation. We have previously demonstrated that MenaINV mRNA and protein expression is induced in cancer cells by macrophage contact. In this study, we discovered the precise mechanism by which macrophages induce MenaINV expression in tumor cells. We examined the promoter of the human and mouse ENAH gene and discovered a conserved NF-κB transcription factor binding site. Using live imaging of an NF-κB activity reporter and staining of fixed tissues from mouse and human breast cancer, we further determined that for maximal induction of MenaINV in cancer cells, NF-κB needs to cooperate with the Notch1 signaling pathway. Mechanistically, Notch1 signaling does not directly increase MenaINV expression, but it enhances and sustains NF-κB signaling through retention of p65, an NF-κB transcription factor, in the nucleus of tumor cells, leading to increased MenaINV expression. In mice, these signals are augmented following chemotherapy treatment and abrogated upon macrophage depletion. Targeting Notch1 signaling in vivo decreased NF-κB signaling activation and MenaINV expression in the primary tumor and decreased metastasis. Altogether, these data uncover mechanistic targets for blocking MenaINV induction that should be explored clinically to decrease cancer cell dissemination and improve survival of patients with metastatic disease.

Biosensor-based active ingredient recognition system for screening TNF-α inhibitors from lotus leaves

Erhuangquzhi granules (EQG) have been clinically proven to be effective in nonalcoholic steatohepatitis (NASH) treatment. However, the active components and molecular mechanisms remain unknown. This study aimed to screen active components targeting tumor necrosis factor α (TNF-α) in EQG for the treatment of NASH by a surface plasmon resonance (SPR) biosensor-based active ingredient recognition system (SPR-AIRS). The amine-coupling method was used to immobilize recombinant TNF-α protein on an SPR chip, the specificity of the TNF-α-immobilized chip was validated, and nine medicinal herbs in EQG were prescreened. Nuciferine (NF), lirinidine (ID), and O-nornuciferine (NNF) from lotus leaves were found and identified as TNF-α ligands by UPLC‒MS/MS, and the affinity constants of NF, ID, and NNF to TNF-α were determined by SPR experiments (Kd = 61.19, 31.02, and 20.71 µM, respectively). NF, ID, and NNF inhibited TNF-α-induced apoptosis in L929 cells, the levels of secreted IL-6 and IL-1β were reduced, and the phosphorylation of IKKβ and IκB was inhibited in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. In conclusion, a class of new active small-molecule TNF-α inhibitors was discovered, which also provides a valuable reference for the material basis and mechanism of EQG action in NASH treatment.

Cooperative NF-κB and Notch1 signaling promotes macrophage-mediated MenaINV expression in breast cancer

Metastasis is a multistep process that leads to the formation of clinically detectable tumor foci at distant organs and frequently patient demise. Only a subpopulation of breast cancer cells within the primary tumor can disseminate systemically and cause metastasis. To disseminate, cancer cells must express MenaINV, an isoform of the actin-regulatory protein Mena encoded by the ENAH gene that endows tumor cells with transendothelial migration activity allowing them to enter and exit the blood circulation. We have previously demonstrated that MenaINV mRNA and protein expression is induced in cancer cells by macrophage contact. In this study, we discovered the precise mechanism by which macrophages induce MenaINV expression in tumor cells. We examined the promoter of the human and mouse ENAH gene and discovered a conserved NF-κB transcription factor binding site. Using live imaging of an NF-κB activity reporter and staining of fixed tissues from mouse and human breast cancer we further determined that for maximal induction of MenaINV in cancer cell NF-κB needs to cooperate with the Notch1 signaling pathway. Mechanistically, Notch1 signaling does not directly increase MenaINV expression, but it enhances and sustains NF-κB signaling through retention of p65, an NF-κB transcription factor, in the nucleus of tumor cells, leading to increased MenaINV expression. In mice, these signals are augmented following chemotherapy treatment and abrogated upon macrophage depletion. Targeting Notch1 signaling in vivo decreased NF-κB signaling and MenaINV expression in the primary tumor and decreased metastasis. Altogether, these data uncover mechanistic targets for blocking MenaINV induction that should be explored clinically to decrease cancer cell dissemination and improve survival of patients with metastatic disease.

Sympathetic modulation of tumor necrosis factor alpha-induced nociception in the presence of oral squamous cell carcinoma

ABSTRACT

Head and neck squamous cell carcinoma (HNSCC) causes more severe pain and psychological stress than other types of cancer. Despite clinical evidence linking pain, stress, and cancer progression, the underlying relationship between pain and sympathetic neurotransmission in oral cancer is unknown. We found that human HNSCC tumors and mouse tumor tissue are innervated by peripheral sympathetic and sensory nerves. Moreover, β-adrenergic 1 and 2 receptors (β-ARs) are overexpressed in human oral cancer cell lines, and norepinephrine treatment increased β-AR2 protein expression as well as cancer cell proliferation in vitro. We have recently demonstrated that inhibition of tumor necrosis factor alpha (TNFα) signaling reduces oral cancer-induced nociceptive behavior. Norepinephrine-treated cancer cell lines secrete more TNFα which, when applied to tongue-innervating trigeminal neurons, evoked a larger Ca 2+ transient; TNF-TNFR inhibitor blocked the increase in the evoked Ca 2+ transient. Using an orthotopic xenograft oral cancer model, we found that mice demonstrated significantly less orofacial cancer-induced nociceptive behavior during systemic β-adrenergic inhibitory treatment with propranolol. Furthermore, chemical sympathectomy using guanethidine led to a significant reduction in tumor size and nociceptive behavior. We infer from these results that sympathetic signaling modulates oral cancer pain through TNFα secretion and tumorigenesis. Further investigation of the role of neurocancer communication in cancer progression and pain is warranted.

An orally active, small-molecule TNF inhibitor that disrupts the homotrimerization interface improves inflammatory arthritis in mice

Excessive signaling by the proinflammatory cytokine TNF is involved in several autoimmune diseases, including rheumatoid arthritis (RA). However, unlike the approved biologics currently used to treat this and other conditions, commercially available small-molecule inhibitors of TNF trimerization are cytotoxic or exhibit low potency. Here, we report a TNF-inhibitory molecule (TIM) that reduced TNF signaling in vitro and was an effective treatment in a mouse model of RA. The initial lead compound, TIM1, attenuated TNF-induced apoptosis of human and mouse cells by delaying the induction of proinflammatory NF-κB and MAPK signaling and caspase 3– and caspase 8–dependent apoptosis. TIM1 inhibited the secretion of the proinflammatory cytokines IL-6 and IL-8 by disrupting TNF homotrimerization, thereby preventing its association with the TNF receptor. In a mouse model of collagen-induced polyarthritis, the more potent TIM1 analog TIM1c was orally bioavailable and reduced paw swelling, histological indicators of knee joint pathology, inflammatory infiltration of the joint, and the overall arthritis index. Orally delivered TIM1c showed immunological effects similar to those elicited by intraperitoneal injection of the FDA-approved TNF receptor decoy etanercept. Thus, TIM1c is a promising lead compound for the development of small-molecule therapies for the treatment of RA and other TNF-dependent systemic inflammation disorders.

A Small Molecule Selected from a DNA-Encoded Library of Natural Products That Binds to TNF-α and Attenuates Inflammation In Vivo

Tumor necrosis factor α (TNF-α) inhibitors have shown great success in the treatment of autoimmune diseases. However, to date, approved drugs targeting TNF-α are restricted to biological macromolecules, largely due to the difficulties in using small molecules for pharmaceutical intervention of protein-protein interactions. Herein the power of a natural product-enriched DNA-encoded library (nDEL) is exploited to identify small molecules that interfere with the protein-protein interaction between TNF-α and the cognate receptor. Initially, to select molecules capable of binding to TNF-α , "late-stage" DNA modification method is applied to construct an nDEL library consisted of 400 sterically diverse natural products and pharmaceutically active chemicals. Several natural products, including kaempferol, identified not only show direct interaction with TNF-α, but also lead to the blockage of TNF-α/TNFR1 interaction. Significantly, kaempferol attenuates the TNF-α signaling in cells and reduces the 12-O-tetradecanoylphorbol-13-acetateinduced ear inflammation in mice. Structure-activity-relationship analyses demonstrate the importance of substitution groups at C-3, C-7, and C-4' of kaempferol. The nDEL hit, kaempferol, represents a novel chemical scaffold capable of specifically recognizing TNF-α and blocking its signal transduction, a promising starting point for the development of a small molecule TNF-α inhibitor for use in the clinical setting.

The anti-inflammatory effects of apigenin and genistein on the rat intestinal epithelial (IEC-6) cells with TNF-α stimulation in response to heat treatment

The aims of the present study were to investigate the anti-inflammatory function of two flavonoids apigenin and genistein in rat intestinal epithelial (IEC-6) cells stimulated by tumor necrosis factor-alpha (TNF-α) and to clarify whether the heat treatment of the flavonoids might affect flavonoid activity. The flavonoids at lower dosage (e.g. 5 μmol/L) had no toxic effect but growth promotion on the cells. Meanwhile, the flavonoid pretreatment of the cells before TNF-α stimulation could maintain cellular morphology, decrease the production of prostaglandin E₂ and two pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-6, but increase the production of two anti-inflammatory cytokines IL-10 and transforming growth factor-β. Additionally, the flavonoids could block off the nuclear translocation of nuclear factor-kappaB (NF-κB) p65, and suppress the expression of phosphorylated IκBα and p65 induced by TNF-α. Meanwhile, the NF-κB inhibitor BAY 11-7082 shared a similar function with the flavonoids to mediate the production of IL-6/IL-10. Furthermore, in silico analysis also declared that the flavonoids could interact with the IκBα-NF-κB complex at the binding pockets to yield the binding energies ranging from -31.7 to -34.0 kJ/mol. However, the heated flavonoids were consistently less effective than the unheated counterparts to perform these anti-inflammatory effects. It is thus proposed that both apigenin and genistein have anti-inflammatory potential to the TNF-α-stimulated IEC-6 cells by inactivating the NF-κB pathway, while heat treatment of the flavonoids caused a negative impact on these assessed anti-inflammatory effects.

Discovery of First-in-Class TAK1-MKK3 Protein-Protein Interaction (PPI) Inhibitor for the Treatment of Ulcerative Colitis through Modulating TNF-α Production

Tumor necrosis factor α (TNF-α) has been demonstrated to be a therapeutic target for autoimmune diseases. However, this biological therapy exhibits some inevitable disadvantages, such as risk of infection. Thus, small-molecule alternatives by targeting TNF-α production signaling pathway are still in demand. Herein, we describe the design, synthesis, and structure-activity relationships of 3-aryindanone compounds regarding their modulation of TNF-α production. Among them, (R)-STU104 exhibited the most potent inhibitory activity on TNF-α production, which suppressed the TAK1/MKK3/p38/MnK1/MK2/elF4E signal pathways through binding with MKK3 and disrupting the TAK1 phosphorylating MKK3. As a result, (R)-STU104 demonstrated remarkable dose-effect relationships on both acute and chronic mouse UC models. In addition to its good pharmacokinetic (PK) and safety profile, (R)-STU104 showed better anti-UC efficacy in vivo at 10 mg/kg/d than mesalazine at the dose of 50 mg/kg/d. These results suggested that TAK1-MKK3 interaction inhibitors could be potentially utilized for the treatment of UC.

TNF-α signaling in non-alcoholic steatohepatitis and targeted therapies

Nonalcoholic steatohepatitis (NASH), an inflammatory subtype of nonalcoholic fatty liver disease (NAFLD), is featured by significantly elevated levels of various pro-inflammatory cytokines. Among numerous pro-inflammatory factors that contribute to NASH pathogenesis, the secreted protein, tumor necrosis factor-alpha (TNF-α) plays an essential role in multiple facets of NASH progression and is therefore considered as a potential therapeutic target. In this review, we will first systematically describe the preclinical studies on the biochemical function of TNF-α and its intracellular downstream signaling mechanisms through its receptors. Moreover, we extensively discuss its functions in regulating inflammation, cell death, and fibrosis of liver cells in the pathogenesis of NASH, and the molecular mechanism that TNF-α expression was regulated by NF-κB and other upstream master regulators during NASH progression. As TNF-α is one of the causal factors that remarkably contributes to NASH progression, combination of therapeutic modalities, including TNF-α-based therapies may lead to resolution of NASH via multiple pathways and thus generate clinical benefits. For translational studies, we summarize recent advances in strategies targeting TNF-α and its signaling pathway, which paves the way for potential therapeutic treatments for NASH in future.

A mechanistic perspective, clinical applications, and phage-display-assisted discovery of TNFα inhibitors

TNFα participates in a variety of physiological processes, but at supra-physiological concentrations it has been implicated in the pathology of inflammatory and autoimmune diseases. Therefore, much attention has been devoted to the development of strategies that overcome the effects of aberrant TNFα concentration. Promising strategies include drugs that destabilize the active (trimeric) form of TNFα and antagonists of TNFα receptor type I. Underpinning these strategies is the successful application of phage-display technology to identify anti-TNFα peptides and antibodies. Here, we review the development of inhibitors of the TNFα-TNF receptor system, with particular focus on the phage-display-assisted identification of molecules that interfere with this system by acting as inhibitors of TNFα or by sequestering TNFα away from its receptor.

A Novel Competitive Binding Screening Assay Reveals Sennoside B as a Potent Natural Product Inhibitor of TNF-α

Natural products (NPs) have played a significant role in drug discovery for diverse diseases, and numerous attempts have been made to discover promising NP inhibitors of tumor necrosis factor α (TNF-α), a major therapeutic target in autoimmune diseases. However, NP inhibitors of TNF-α, which have the potential to be developed as new drugs, have not been reported for over a decade. To facilitate the search for new promising inhibitors of TNF-α, we developed an efficient competitive binding screening assay based on analytical size exclusion chromatography coupled with liquid chromatography-tandem mass spectrometry. Application of this screening method to the NP library led to the discovery of a potent inhibitor of TNF-α, sennoside B, with an IC₅₀ value of 0.32 µM in TNF-α induced HeLa cell toxicity assays. Surprisingly, the potency of sennoside B was 5.7-fold higher than that of the synthetic TNF-α inhibitor SPD304. Molecular docking was performed to determine the binding mode of sennoside B to TNF-α. In conclusion, we successfully developed a novel competition binding screening method to discover small molecule TNF-α inhibitors and identified the natural compound sennoside B as having exceptional potency.

Rationally designed TNF-α inhibitors: Identification of promising cytotoxic agents

Design and synthesis of new indole derivatives as tumor growth inhibiting agents via inhibiting the TNF-α is described. The preliminary results showed the inhibition of LPS induced production of NO, TNF-α and IL-6 by these compounds out of which compounds 2d and 2g exhibited appreciable cytotoxicity against the 60 cell lines panel of human cancer. The rationale behind the design of the molecules and the results of their biological studies are presented. 2009 Elsevier Ltd. All rights reserved.

Tumor Necrosis Factor Alpha-Mediated Inflammation and Remodeling of the Extracellular Matrix Underlies Aortic Stiffening Induced by the Common Chemotherapeutic Agent Doxorubicin

[Figure: see text].

TNFα promotes oral cancer growth, pain, and Schwann cell activation

Oral cancer is very painful and impairs a patient's ability to eat, talk, and drink. Mediators secreted from oral cancer can excite and sensitize sensory neurons inducing pain. Cancer mediators can also activate Schwann cells, the peripheral glia that regulates neuronal function and repair. The contribution of Schwann cells to oral cancer pain is unclear. We hypothesize that the oral cancer mediator TNFα activates Schwann cells, which further promotes cancer progression and pain. We demonstrate that TNFα is overexpressed in human oral cancer tissues and correlates with increased self-reported pain in patients. Antagonizing TNFα reduces oral cancer proliferation, cytokine production, and nociception in mice with oral cancer. Oral cancer or TNFα alone increases Schwann cell activation (measured by Schwann cell proliferation, migration, and activation markers), which can be inhibited by neutralizing TNFα. Cancer- or TNFα-activated Schwann cells release pro-nociceptive mediators such as TNFα and nerve growth factor (NGF). Activated Schwann cells induce nociceptive behaviors in mice, which is alleviated by blocking TNFα. Our study suggests that TNFα promotes cancer proliferation, progression, and nociception at least partially by activating Schwann cells. Inhibiting TNFα or Schwann cell activation might serve as therapeutic approaches for the treatment of oral cancer and associated pain.

Development and characterization of a novel, megakaryocyte NF-κB reporter cell line for investigating inflammatory responses

Essentials An easily detectable readout in megakaryocyte cell lines will enhance inflammatory research in these cells. Here, we report the development and characterization of a novel megakaryocyte NF-κB-reporter cell line (Meg-01R). Multiple inflammatory molecules modulate NF-κB activity in Meg-01R cells. Meg-01R cells respond to small molecule inhibitors such as IMD0354 and C87 that are known to inhibit NF-κB activity upon stimulation with TNFα. ABSTRACT: Background Because of the difficulties in acquiring large numbers of megakaryocytes, the impact of inflammatory responses on these cells and their ability to produce fully functional platelets under various pathological conditions has not been investigated in detail. Objectives The primary objective of this study is to develop and functionally characterize a novel megakaryocyte nuclear factor κB (NF-κB) reporter cell line to determine the effects of various inflammatory molecules on megakaryocytes and their signalling pathways. Methods A Meg-01-NF-κB-GFP-Luc (Meg-01R) cell line was developed by inserting a reporter NF-κB-GFP-Luc cassette into normal Meg-01 cells to produce luciferase following activation of NF-κB to enable easy detection of pro-inflammatory and reparative signalling. Results and conclusions Meg-01 and Meg-01R cells have comparable characteristics, including the expression of both GPIbα and integrin β3 . Meg-01R cells responded to various inflammatory molecules as measured by NF-κB-dependent bioluminescence. For example, inflammatory molecules such as tumor necrosis factor-α and Pam3CSK4 increased NF-κB activity, whereas an antimicrobial peptide, LL37, reduced its activity. Meg-01R cells were also found to be sensitive to inhibitors (IMD0354 and C87) of inflammatory pathways. Notably, Meg-01R cells were able to respond to lipopolysaccharide (LPS; non-ultrapure), although it was not able to react to ultrapure LPS because of the lack of sufficient TLR4 molecules on their surface. For the first time, we report the development and characterization of a novel megakaryocyte NF-κB reporter cell line (Meg-01R) as a robust tool to study the inflammatory responses/signalling of megakaryocytes upon stimulation with a broad range of inflammatory molecules that can affect NF-κB activity.

A Rational Insight into the Effect of Dimethyl Sulfoxide on TNF-α Activity

Direct inhibition of tumor necrosis factor-alpha (TNF-α) action is considered a promising way to prevent or treat TNF-α-associated diseases. The trimeric form of TNF-α binds to its receptor (TNFR) and activates the downstream signaling pathway. The interaction of TNF-α with molecular-grade dimethyl sulfoxide (DMSO) in an equal volumetric ratio renders TNF-α inert, in this state, TNF-α fails to activate TNFR. Here, we aimed to examine the inhibition of TNF-α function by various concentrations of DMSO. Its higher concentration led to stronger attenuation of TNF-α-induced cytokine secretion by fibroblasts, and of their death. We found that this inhibition was mediated by a perturbation in the formation of the functional TNF-α trimer. Molecular dynamics simulations revealed a transient interaction between DMSO molecules and the central hydrophobic cavity of the TNF-α homodimer, indicating that a brief interaction of DMSO with the TNF-α homodimer may disrupt the formation of the functional homotrimer. We also found that the sensitizing effect of actinomycin D on TNF-α-induced cell death depends upon the timing of these treatments and on the cell type. This study will help to select an appropriate concentration of DMSO as a working solvent for the screening of water-insoluble TNF-α inhibitors.

Noncompetitive Allosteric Antagonism of Death Receptor 5 by a Synthetic Affibody Ligand

Fatty acid-induced upregulation of death receptor 5 (DR5) and its cognate ligand, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), promotes hepatocyte lipoapoptosis, which is a key mechanism in the progression of fatty liver disease. Accordingly, inhibition of DR5 signaling represents an attractive strategy for treating fatty liver disease. Ligand competition strategies are prevalent in tumor necrosis factor receptor antagonism, but recent studies have suggested that noncompetitive inhibition through perturbation of the receptor conformation may be a compelling alternative. To this end, we used yeast display and a designed combinatorial library to identify a synthetic 58-amino acid affibody ligand that specifically binds DR5. Biophysical and biochemical studies show that the affibody neither blocks TRAIL binding nor prevents the receptor-receptor interaction. Live-cell fluorescence lifetime measurements indicate that the affibody induces a conformational change in transmembrane dimers of DR5 and favors an inactive state of the receptor. The affibody inhibits apoptosis in TRAIL-treated Huh-7 cells, an in vitro model of fatty liver disease. Thus, this lead affibody serves as a potential drug candidate, with a unique mechanism of action, for fatty liver disease.

Microglia-Triggered Plasticity of Intrinsic Excitability Modulates Psychomotor Behaviors in Acute Cerebellar Inflammation

Cerebellar dysfunction relates to various psychiatric disorders, including autism spectrum and depressive disorders. However, the physiological aspect is less advanced. Here, we investigate the immune-triggered hyperexcitability in the cerebellum on a wider scope. Activated microglia via exposure to bacterial endotoxin lipopolysaccharide or heat-killed Gram-negative bacteria induce a potentiation of the intrinsic excitability in Purkinje neurons, which is suppressed by microglia-activity inhibitor and microglia depletion. An inflammatory cytokine, tumor necrosis factor alpha (TNF-α), released from microglia via toll-like receptor 4, triggers this plasticity. Our two-photon FRET ATP imaging shows an increase in ATP concentration following endotoxin exposure. Both TNF-α and ATP secretion facilitate synaptic transmission. Region-specific inflammation in the cerebellum in vivo shows depression- and autistic-like behaviors. Furthermore, both TNF-α inhibition and microglia depletion revert such behavioral abnormality. Resting-state functional MRI reveals overconnectivity between the inflamed cerebellum and the prefrontal neocortical regions. Thus, immune activity in the cerebellum induces neuronal hyperexcitability and disruption of psychomotor behaviors in animals.

Structural insight into TNF-α inhibitors through combining pharmacophore-based virtual screening and molecular dynamic simulation

Tumor Necrosis Factor-alpha (TNF-α), a multifunctional cytokine responsible for providing resistance against infections, inflammation, and cancers. TNF-α has emerged as a promising drug target against several autoimmune and inflammatory disorders. Several synthetic antibodies (Infliximab, Etanercept, and Adalimumab) are available, but their potential to cause severe side effects has prompted them to develop alternative small molecules-based therapies for inhibition of TNF-α. In the present study, combined in silico approaches based on pharmacophore modeling, virtual screening, molecular docking, and molecular dynamics studies were employed to understand significant direct interactions between TNF-α protein and small molecule inhibitors. Initially, four different small molecule libraries (∼17.5 million molecules) were virtually screened against the selected pharmacophore model. The identified hits were further subjected to molecular docking studies. The three potent lead compounds (ZINC05848961, ZINC09402309, ZINC04502991) were further subjected to 100 ns molecular dynamic studies to examine their stability. Our docking and molecular dynamic analysis revealed that the selected lead compounds target the TNF receptor (TNFR) and efficiently block the production of TNF. Moreover, in silico ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) analysis revealed that all the predicted compounds have good pharmacokinetic properties with high gastrointestinal absorption and a decent bioavailability score. Furthermore, toxicity profiles further evidenced that these compounds have no risk of being mutagenic, tumorigenic, reproductive and irritant except ZINC11915498. In conclusion, the present study could serve as the starting point to develop new therapeutic regimens to treat various TNF- related diseases. Communicated by Ramaswamy H. Sarma.

Fibroblast transdifferentiation promotes conversion of M1 macrophages and replenishment of cardiac resident macrophages following cardiac injury in mice

Resident cardiac macrophages play important roles in homeostasis, maintenance of cardiac function, and tissue repair. After cardiac injury, monocytes infiltrate the tissue, undergo phenotypic and functional changes, and are involved in inflammatory injury and functional remodelling. However, the fate of cardiac infiltrating/polarized macrophages and the relationship between these cells and resident cardiac macrophage replenishment following injury remain unclear. Our results showed that angiotensin II induces cardiac fibroblast transdifferentiation into cardiac myofibroblasts (MFBs). In cocultures with MFBs and murine macrophages, the MFBs promoted macrophage polarization to M1 phenotype, followed by selective apoptosis, which was associated with TNF/TNFR1 axis and independent of NO production. Surprisingly, after 36 h of coculture, the surviving macrophages were converted to M2 phenotype and settled in heart, which was dependent on leptin produced by MFBs or polarized macrophages via the PI3K or Akt pathway. CCR2⁺ CD45.2⁺ cells adoptively transferred into CD45.1⁺ mice with viral myocarditis, differentiated into CD45.2⁺ CCR2⁺ CX3CR1⁺ M2 cells during the resolution of inflammation and settled within the heart. Our data highlight a novel mechanism related to the renewal or replenishment of cardiac resident macrophages following cardiac injury; and suggest that transdifferentiation of cardiac fibroblasts may promote the resolution of inflammation.

Protein-protein interactions: a structural view of inhibition strategies and the IL-23/IL-17 axis

Protein-protein interactions are central to biology and provide opportunities to modulate disease with small-molecule or protein therapeutics. Recent developments in the understanding of the tractability of protein-protein interactions are discussed with a focus on the ligandable nature of protein-protein interaction surfaces. General principles of inhibiting protein-protein interactions are illustrated with structural biology examples from six members of the IL-23/IL-17 signaling family (IL-1, IL-6, IL-17, IL-23 RORγT and TNFα). These examples illustrate the different approaches to discover protein-protein interaction inhibitors on a target-specific basis that has proven fruitful in terms of discovering both small molecule and biologic based protein-protein interaction inhibitors.

Overexpression of the C-domain of angiotensin-converting enzyme reduces melanoma growth by stimulating M1 macrophage polarization

Angiotensin-converting enzyme (ACE) can hydrolyze many peptides and plays a central role in controlling blood pressure. Moreover, ACE overexpression in monocytes and macrophages increases resistance of mice to tumor growth. ACE is composed of two independent catalytic domains. Here, to investigate the specific role of each domain in tumor resistance, we overexpressed either WT ACE (Tg-ACE mice) or ACE lacking N- or C-domain catalytic activity (Tg-NKO and Tg-CKO mice) in the myeloid cells of mice. Tg-ACE and Tg-NKO mice exhibited strongly suppressed growth of B16-F10 melanoma because of increased ACE expression in macrophages, whereas Tg-CKO mice resisted melanoma no better than WT animals. The effect of ACE overexpression reverted to that of the WT enzyme with an ACE inhibitor but not with an angiotensin II type 1 (AT1) receptor antagonist. ACE C-domain overexpression in macrophages drove them toward a pronounced M1 phenotype upon tumor stimulation, with increased activation of NF-κB and signal transducer and activator of transcription 1 (STAT1) and decreased STAT3 and STAT6 activation. Tumor necrosis factor α (TNFα) is important for M1 activation, and TNFα blockade reverted Tg-NKO macrophages to a WT phenotype. Increased ACE C-domain expression increased the levels of reactive oxygen species (ROS) and of the transcription factor C/EBPβ in macrophages, important stimuli for TNFα expression, and decreased expression of several M2 markers, including interleukin-4Rα. Natural ACE C-domain-specific substrates are not well-described, and we propose that the peptide(s) responsible for the striking ACE-mediated enhancement of myeloid function are substrates/products of the ACE C-domain.

Sertraline ameliorates inflammation in CUMS mice and inhibits TNF-α-induced inflammation in microglia cells

Evidence indicates that inflammation plays a crucial role in depression. Therefore, new antidepressants might be identified by screening drugs for their anti-inflammatory actions. Sertraline hydrochloride (SERT), a widely used antidepressant, has anti-inflammatory effects in clinical studies, but the mechanism involved is unclear. In this study, we used cell and molecular biology to determine the possible anti-inflammatory mechanism of SERT in vivo and in vitro. Experimental data from the in vivo study showed that mice exposed to chronic unpredictable mild stress (CUMS) had significantly higher levels of major inflammatory cytokines (tumor necrosis factor-α [TNF-α], interleukin-1β [IL-1β] and inducible nitric oxide synthase [iNOS]) in peripheral and central tissues compared with the control group. Treatment of CUMS mice with SERT significantly reduced the levels of these inflammatory cytokines and inhibited the phosphorylation of nuclear factor-κB (NF-κB) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκB-α). Moreover, SERT reduced serum levels of transaminase in CUMS mice. Our in vitro study revealed that SERT suppressed TNF-α-induced NF-κB activation in a dose-dependent manner. SERT also inhibited the TNF-α-induced nuclear translocation of NF-κB by inhibiting IκB-α phosphorylation. Furthermore, SERT inhibited TNF-α-induced inflammatory cytokines in BV2 microglia cells. SERT directly bound to TNF-α and TNF-α receptor 1 (TNFR1) to potently block TNF-α/TNFR1-triggered signaling. These results indicate that SERT might treat depression by inhibiting the activation of microglia via the NF-κB signaling pathway. This study provides a basis for the research and development of antidepressants that act to reduce inflammation and the expression of inflammatory mediators.

Incorporation of macrophages into engineered skeletal muscle enables enhanced muscle regeneration

Adult skeletal muscle has a robust capacity for self-repair, owing to synergies between muscle satellite cells and the immune system. In vitro models of muscle self-repair would facilitate the basic understanding of muscle regeneration and the screening of therapies for muscle disease. Here, we show that the incorporation of macrophages into muscle tissues engineered from adult-rat myogenic cells enables near-complete structural and functional repair after cardiotoxic injury in vitro. First, we show that-in contrast with injured neonatal-derived engineered muscle-adult-derived engineered muscle fails to properly self-repair after injury, even when treated with pro-regenerative cytokines. We then show that rat bone-marrow-derived macrophages or human blood-derived macrophages resident within the in vitro engineered tissues stimulate muscle satellite cell-mediated myogenesis while significantly limiting myofibre apoptosis and degeneration. Moreover, bone-marrow-derived macrophages within engineered tissues implanted in a mouse dorsal window-chamber model augmented blood vessel ingrowth, cell survival, muscle regeneration and contractile function.

Tumor necrosis factor alpha secreted from oral squamous cell carcinoma contributes to cancer pain and associated inflammation

Patients with oral cancer report severe pain during function. Inflammation plays a role in the oral cancer microenvironment; however, the role of immune cells and associated secretion of inflammatory mediators in oral cancer pain has not been well defined. In this study, we used 2 oral cancer mouse models: a cell line supernatant injection model and the 4-nitroquinoline-1-oxide (4NQO) chemical carcinogenesis model. We used the 2 models to study changes in immune cell infiltrate and orofacial nociception associated with oral squamous cell carcinoma (oSCC). Oral cancer cell line supernatant inoculation and 4NQO-induced oSCC resulted in functional allodynia and neuronal sensitization of trigeminal tongue afferent neurons. Although the infiltration of immune cells is a prominent component of both oral cancer models, our use of immune-deficient mice demonstrated that oral cancer-induced nociception was not dependent on the inflammatory component. Furthermore, the inflammatory cytokine, tumor necrosis factor alpha (TNFα), was identified in high concentration in oral cancer cell line supernatant and in the tongue tissue of 4NQO-treated mice with oSCC. Inhibition of TNFα signaling abolished oral cancer cell line supernatant-evoked functional allodynia and disrupted T-cell infiltration. With these data, we identified TNFα as a prominent mediator in oral cancer-induced nociception and inflammation, highlighting the need for further investigation in neural-immune communication in cancer pain.

Synthesis of Chiral cis-Cyclopropane Bearing Indole and Chromone as Potential TNFα Inhibitors

Conformationally restricted analogues of SPD-304, the first small-molecule TNFα inhibitor, in which two heteroaryl groups, indole and chromone, are connected by chiral methyl- or ethyl- cis-cyclopropane, were designed. Synthesis of these molecules was achieved via Suzuki-Miyaura or Stille coupling reactions with chiral bromomethylenecyclopropane or iodovinyl- cis-cyclopropane as the substrate, both of which were prepared from chiral methylenecyclopropane as a common intermediate, constructing the heteroaryl-methyl or -ethyl- cis-cyclopropane structures as key steps. This study presents an efficient synthesis of a series of chiral cis-cyclopropane conjugates with two heteroaryl groups.

TNF Receptor Type II as an Emerging Drug Target for the Treatment of Cancer, Autoimmune Diseases, and Graft-Versus-Host Disease: Current Perspectives and In Silico Search for Small Molecule Binders

There is now compelling evidence that TNF receptor type II (TNFR2) is predominantly expressed on CD4⁺Foxp3⁺ regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs), and plays a major role in the expansion and function of Tregs and MDSCs. Consequently, targeting of TNFR2 by either antagonists or agonists may represent a novel strategy in the treatment of cancer and autoimmune diseases, by downregulating or upregulating suppressor cell activity. The advance in the understanding of complex structure of TNFR2 and its binding with TNF at molecular levels offers opportunity for structure-guided drug discovery. This article reviews the current evidences regarding the decisive role of TNFR2 in immunosuppressive function of Tregs and MDSCs, and the current effort to develop novel TNFR2-targeting therapeutic agents in the treatment of cancer, autoimmune diseases, and graft-versus-host disease. To shed light on the potential TNFR2-targeting small molecules, we for the first time performed virtual screening of 400,000 natural compounds against the two TNF-binding sites, regions 3 and 4, of TNFR2. Our result showed that the top hits at region 4 had slightly higher docking energies than those at region 3. Nevertheless, free energy calculation from the TNF–TNFR2 molecular dynamics simulation revealed that the binding strength of TNF in region 3 is only one-tenth of that in region 4. This suggests that region 3 is a potentially more viable binding site to be targeted by small molecules than region 4. Therefore, the effectiveness in targeting region 3 of TNFR2 deserves further investigation.

A New Venue of TNF Targeting

The first Food and Drug Administration-(FDA)-approved drugs were small, chemically-manufactured and highly active molecules with possible off-target effects, followed by protein-based medicines such as antibodies. Conventional antibodies bind a specific protein and are becoming increasingly important in the therapeutic landscape. A very prominent class of biologicals are the anti-tumor necrosis factor (TNF) drugs that are applied in several inflammatory diseases that are characterized by dysregulated TNF levels. Marketing of TNF inhibitors revolutionized the treatment of diseases such as Crohn’s disease. However, these inhibitors also have undesired effects, some of them directly associated with the inherent nature of this drug class, whereas others are linked with their mechanism of action, being pan-TNF inhibition. The effects of TNF can diverge at the level of TNF format or receptor, and we discuss the consequences of this in sepsis, autoimmunity and neurodegeneration. Recently, researchers tried to design drugs with reduced side effects. These include molecules with more specificity targeting one specific TNF format or receptor, or that neutralize TNF in specific cells. Alternatively, TNF-directed biologicals without the typical antibody structure are manufactured. Here, we review the complications related to the use of conventional TNF inhibitors, together with the anti-TNF alternatives and the benefits of selective approaches in different diseases.

Design, Synthesis, and Evaluation of Dihydrobenzo[cd]indole-6-sulfonamide as TNF-α Inhibitors

Tumor necrosis factor-α (TNF-α) plays a pivotal role in inflammatory response. Dysregulation of TNF can lead to a variety of disastrous pathological effects, including auto-inflammatory diseases. Antibodies that directly targeting TNF-α have been proven effective in suppressing symptoms of these disorders. Compared to protein drugs, small molecule drugs are normally orally available and less expensive. Till now, peptide and small molecule TNF-α inhibitors are still in the early stage of development, and much more efforts should be made. In a previously study, we reported a TNF-α inhibitor, EJMC-1 with modest activity. Here, we optimized this compound by shape screen and rational design. In the first round, we screened commercial compound library for EJMC-1 analogs based on shape similarity. Out of the 68 compounds tested, 20 compounds showed better binding affinity than EJMC-1 in the SPR competitive binding assay. These 20 compounds were tested in cell assay and the most potent compound was 2-oxo-N-phenyl-1,2-dihydrobenzo[cd]indole-6-sulfonamide (S10) with an IC₅₀ of 14 μM, which was 2.2-fold stronger than EJMC-1. Based on the docking analysis of S10 and EJMC-1 binding with TNF-α, in the second round, we designed S10 analogs, purchased seven of them, and synthesized seven new compounds. The best compound, 4e showed an IC₅₀-value of 3 μM in cell assay, which was 14-fold stronger than EJMC-1. 4e was among the most potent TNF-α organic compound inhibitors reported so far. Our study demonstrated that 2-oxo-N-phenyl-1,2-dihydrobenzo[cd]indole-6-sulfonamide analogs could be developed as potent TNF-α inhibitors. 4e can be further optimized for its activity and properties. Our study provides insights into designing small molecule inhibitors directly targeting TNF-α and for protein–protein interaction inhibitor design.

Computer-aided design of short peptide ligands targeting tumor necrosis factor-alpha for adsorbent applications

A peptide ligand (T1: Ac-RKEM-NH₂) designed by a computer-aided method can enhance TNF-α adsorption from the plasma of rats with sepsis to PVA.

Metabolic regulations of a decoction of Hedyotis diffusa in acute liver injury of mouse models

Background

Dysfunctional metabolisms are contributed to LPS/GALN-induced hepatitis. However, whether Hedyotis diffusa (HD) employs metabolic strategies against hepatitis is unknown.

Methods

We use the cytokines expression, levels of serum alanine transaminase and aspartate transaminase, survival and histological analysis to measure the effect of decoction of HD on acute severe hepatitis of mouse induced by LPS/GALN. Meanwhile, we utilize GC/MS-based metabolomics to characterize the variation of metabolomes.

Results

The present study shows the relieving liver damage in HD decoction-treated mice. Metabolic category using differential metabolites indicates the lower percentage of carbohydrates in LPS/GALN + HD group than LPS/GALN group, revealing the value of carbohydrate metabolism in HD decoction-administrated mouse liver. Further pathway enrichment analysis proposes that citrate cycle, galactose metabolism, and starch and sucrose metabolism are three important carbohydrate metabolisms that involve in the protective effect of decoction of HD during acute hepatitis. Furthermore, other important enrichment pathways are biosynthesis of unsaturated fatty acids, alanine, aspartate and glutamate metabolism, and arginine and proline metabolism. Fatty acids or amino acids involved in above-mentioned pathways are also detected in high loading distribution on IC01 and IC02, thereby manifesting the significance of these metabolites. Other key metabolites detect in ICA analysis were cholesterol, lactic acid and tryptophan.

Conclusions

The variation tendency of above-mentioned metabolites is totally consistent with the protective nature of decoction of HD. These findings give a viewpoint that HD decoction-effected metabolic strategies are linked to underlying mechanisms of decoction of HD and highlight the importance of metabolic mechanisms against hepatitis.

Electronic supplementary material

The online version of this article (10.1186/s13020-017-0159-4) contains supplementary material, which is available to authorized users.

Identification of an in vivo orally active dual-binding protein-protein interaction inhibitor targeting TNFα through combined in silico/in vitro/in vivo screening

TNFα is a homotrimeric pro-inflammatory cytokine, whose direct targeting by protein biotherapies has been an undeniable success for the treatment of chronic inflammatory diseases. Despite many efforts, no orally active drug targeting TNFα has been identified so far. In the present work, we identified through combined in silico/in vitro/in vivo approaches a TNFα direct inhibitor, compound 1, displaying nanomolar and micromolar range bindings to TNFα. Compound 1 inhibits the binding of TNFα with both its receptors TNFRI and TNFRII. Compound 1 inhibits the TNFα induced apoptosis on L929 cells and the TNFα induced NF-κB activation in HEK cells. In vivo, oral administration of compound 1 displays a significant protection in a murine TNFα-dependent hepatic shock model. This work illustrates the ability of low-cost combined in silico/in vitro/in vivo screening approaches to identify orally available small-molecules targeting challenging protein-protein interactions such as homotrimeric TNFα.

Discovery of Novel Ligands for TNF-α and TNF Receptor-1 through Structure-Based Virtual Screening and Biological Assay

Tumor necrosis factor α (TNF-α) is overexpressed in various diseases, and it has been a validated therapeutic target for autoimmune diseases. All therapeutics currently used to target TNF-α are biomacromolecules, and limited numbers of TNF-α chemical inhibitors have been reported, which makes the identification of small-molecule alternatives an urgent need. Recent studies have mainly focused on identifying small molecules that directly bind to TNF-α or TNF receptor-1 (TNFR1), inhibit the interaction between TNF-α and TNFR1, and/or regulate related signaling pathways. In this study, we combined in silico methods with biophysical and cell-based assays to identify novel antagonists that bind to TNF-α or TNFR1. Pharmacophore model filtering and molecular docking were applied to identify potential TNF-α antagonists. In regard to TNFR1, we constructed a three-dimensional model of the TNF-α-TNFR1 complex and carried out molecular dynamics simulations to sample the conformations. The residues in TNF-α that have been reported to play important roles in the TNF-α-TNFR1 complex were removed to form a pocket for further virtual screening of TNFR1-binding ligands. We obtained 20 virtual hits and tested them using surface plasmon resonance-based assays, which resulted in one ligand that binds to TNFR1 and four ligands with different scaffolds that bind to TNF-α. T1 and R1, the two most active compounds with Kd values of 11 and 16 μM for TNF-α and TNFR1, respectively, showed activities similar to those of known antagonists. Further cell-based assays also demonstrated that T1 and R1 have similar activities compared to the known TNF-α antagonist C87. Our work has not only produced several TNF-α and TNFR1 antagonists with novel scaffolds for further structural optimization but also showcases the power of our in silico methods for TNF-α- and TNFR1-based drug discovery.

Multifactorial Experimental Design to Optimize the Anti-Inflammatory and Proangiogenic Potential of Mesenchymal Stem Cell Spheroids

Mesenchymal stem cell therapies promote wound healing by manipulating the local environment to enhance the function of host cells. Aggregation of mesenchymal stem cells (MSCs) into three-dimensional spheroids increases cell survival and augments their anti-inflammatory and proangiogenic potential, yet there is no consensus on the preferred conditions for maximizing spheroid function in this application. The objective of this study was to optimize conditions for forming MSC spheroids that simultaneously enhance their anti-inflammatory and proangiogenic nature. We applied a design of experiments (DOE) approach to determine the interaction between three input variables (number of cells per spheroid, oxygen tension, and inflammatory stimulus) on MSC spheroids by quantifying secretion of prostaglandin E₂ (PGE₂ ) and vascular endothelial growth factor (VEGF), two potent molecules in the MSC secretome. DOE results revealed that MSC spheroids formed with 40,000 cells per spheroid in 1% oxygen with an inflammatory stimulus (Spheroid 1) would exhibit enhanced PGE₂ and VEGF production versus those formed with 10,000 cells per spheroid in 21% oxygen with no inflammatory stimulus (Spheroid 2). Compared to Spheroid 2, Spheroid 1 produced fivefold more PGE₂ and fourfold more VEGF, providing the opportunity to simultaneously upregulate the secretion of these factors from the same spheroid. The spheroids induced macrophage polarization, sprout formation with endothelial cells, and keratinocyte migration in a human skin equivalent model-demonstrating efficacy on three key cell types that are dysfunctional in chronic non-healing wounds. We conclude that DOE-based analysis effectively identifies optimal culture conditions to enhance the anti-inflammatory and proangiogenic potential of MSC spheroids. Stem Cells 2017;35:1493-1504.

Synthesis of tumor necrosis factor α for use as a mirror-image phage display target

Tumor Necrosis Factor alpha (TNFα) is an inflammatory cytokine that plays a central role in the pathogenesis of chronic inflammatory disease. Here we describe the chemical synthesis of l-TNFα along with the mirror-image d-protein for use as a phage display target. The synthetic strategy utilized native chemical ligation and desulfurization to unite three peptide segments, followed by oxidative folding to assemble the 52 kDa homotrimeric protein. This synthesis represents the foundational step for discovering an inhibitory d-peptide with the potential to improve current anti-TNFα therapeutic strategies.

Modulation of Protein-Protein Interactions for the Development of Novel Therapeutics

Protein-protein interactions (PPIs) underlie most biological processes. An increasing interest to investigate the unexplored potential of PPIs in drug discovery is driven by the need to find novel therapeutic targets for a whole range of diseases with a high unmet medical need. To date, PPI inhibition with small molecules is the mechanism that has most often been explored, resulting in significant progress towards drug development. However, also PPI stabilization is gradually gaining ground. In this review, we provide a focused overview of a number of PPIs that control critical regulatory pathways and constitute targets for the design of novel therapeutics. We discuss PPI-modulating small molecules that are already pursued in clinical trials. In addition, we review a number of PPIs that are still under preclinical investigation but for which preliminary data support their use as therapeutic targets.

An overview of developing TNF-α targeted therapy for the treatment of psoriasis

INTRODUCTION

Three biologic drugs targeting TNF-α are approved to treat moderate-to-severe cutaneous psoriasis. These are adalimumab, etanercept and infliximab. These drugs are given by subcutaneous injection or intravenous infusion, and while generally safe and effective, they are expensive with potential for side effects. Thus, numerous new drug candidates are under development that also target TNF-α.

AREAS COVERED

In this review, the authors detail several drugs under development that target TNF-α, focusing on those drugs in preclinical, Phase I and II trials. The authors describe emerging biologic psoriasis therapies, including biosimilars and novel biologics, in addition to several synthetic and naturally derived small-molecule drug candidates.

EXPERT OPINION

The currently approved TNF-α antagonists benefit from over 10 years of safety and efficacy data. The expense and method of administration of these biologics, however, can be cumbersome, and less expensive alternatives have the potential to benefit patients with psoriasis. It is inevitable, despite the introduction of new anti-IL-17 therapies, that established TNF-α targeted therapies, as well as newcomers targeting TNF-α, will continue to play an important role in the lifelong management of psoriasis.

Structure-based rational design of peptide hydroxamic acid inhibitors to target tumor necrosis factor-α converting enzyme as potential therapeutics for hepatitis

The human tumor necrosis factor-α converting enzyme (TACE) has recently been raised as a new and promising therapeutic target of hepatitis and other inflammatory diseases. Here, we reported a successful application of the solved crystal structure of TACE complex with a peptide-like ligand INN for rational design of novel peptide hydroxamic acid inhibitors with high potency and selectivity to target and inhibit TACE. First, the intermolecular interactions between TACE catalytic domain and INN were characterized through an integrated bioinformatics approach, with which the key substructures of INN that dominate ligand binding were identified. Subsequently, the INN molecular structure was simplified to a chemical sketch of peptide hydroxamic acid compound, which can be regarded as a linear tripeptide capped by a N-terminal carboxybenzyl group (chemically protective group) and a C-terminal hydroxamate moiety (coordinated to the Zn(2+) at TACE active site). Based on the sketch, a virtual combinatorial library containing 180 peptide hydroxamic acids was generated, from which seven samples were identified as promising candidates by using a knowledge-based protein-peptide affinity predictor and were then tested in vitro with a standard TACE activity assay protocol. Consequently, three designed peptide hydroxamic acids, i.e. Cbz-Pro-Ile-Gln-hydroxamic acid, Cbz-Leu-Ile-Val-hydroxamic acid and Cbz-Phe-Val-Met-hydroxamic acid, exhibited moderate or high inhibitory activity against TACE, with inhibition constants Ki of 36 ± 5, 510 ± 46 and 320 ± 26 nM, respectively. We also examined the structural basis and non-bonded profile of TACE interaction with a designed peptide hydroxamic acid inhibitor, and found that the inhibitor ligand is tightly buried in the active pocket of TACE, forming a number of hydrogen bonds, hydrophobic forces and van der Waals contacts at the interaction interface, conferring both stability and specificity for TACE-inhibitor complex architecture.

Role of tumor necrosis factor alpha in the pathogenesis of atrial fibrillation: A novel potential therapeutic target?

Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice and a major cause of morbidity and mortality. Although the fundamental mechanisms underlying AF remain incompletely understood, atrial remodeling, including structural, electrical, contractile, and autonomic remodeling, has been demonstrated to contribute to the substrate for AF maintenance. Accumulating evidence shows that tumor necrosis factor alpha (TNF-α) plays exceedingly important roles in atrial remodeling. This article reviews recent advances in the roles of TNF-α in the pathogenesis of AF, elucidates the related mechanisms, and exploits its potential usefulness as a novel therapeutic target.