JAK inhibition ameliorated experimental autoimmune encephalomyelitis by blocking GM-CSF-driven inflammatory signature of monocytes.

Monocytes are key effectors in autoimmunity-related diseases in the central nervous system (CNS) due to the critical roles of these cells in the production of proinflammatory cytokines, differentiation of T-helper (Th) cells, and antigen presentation. The JAK-STAT signaling is crucial for initiating monocytes induced immune responses by relaying cytokines signaling. However, the role of this pathway in modulating the communication between monocytes and Th cells in the pathogenesis of multiple sclerosis (MS) is unclear. Here, we show that the JAK1/2/3 and STAT1/3/5/6 subtypes involved in the demyelination mediated by the differentiation of pathological Th1 and Th17 and the CNS-infiltrating inflammatory monocytes in experimental autoimmune encephalomyelitis (EAE), a model for MS. JAK inhibition prevented the CNS-infiltrating CCR2-dependent Ly6Chi monocytes and monocyte-derived dendritic cells in EAE mice. In parallel, the proportion of GM-CSF+CD4+ T cells and GM-CSF secretion were decreased in pathological Th17 cells by JAK inhibition, which in turns converted CNS-invading monocytes into antigen-presenting cells to mediate tissue damage. Together, our data highlight the therapeutic potential of JAK inhibition in treating EAE by blocking the GM-CSF-driven inflammatory signature of monocytes.

A synthetic derivative of bioactive constituents from Isatis indigotica ameliorates hypersensitivity and arthritis by inhibiting JAK2-STAT3 pathway in mice.

The JAK-STAT pathway plays a crucial role in the signaling cascade associated with various cytokines that have been implicated in the pathogenesis of inflammatory diseases and myeloproliferative neoplasms (MPN). Among the isoforms of JAKs, the JAK2 subtype is primarily responsible for the function of hematopoietic system cells, making it a significant target in the treatment of MPN. However, the precise regulatory role of JAK2 in inflammatory diseases requires further investigation and confirmation. The current study employed a selective JAK2 inhibitor, ZT55, derived from Isatis indigotica roots, to examine its regulatory effects on inflammatory and immune responses in delayed-type hypersensitivity (DTH) and arthritis in mice. To evaluate the efficacy of ZT55 treatment, DNFB-induced DTH and collagen-induced arthritis (CIA) mouse models were utilized. T cells were cultured and subsequently analyzed for proliferation and activation using flow cytometry and EdU assay. Additionally, the maturation and function of dendritic cells were assessed through flow cytometry and ELISA. Our findings indicate that ZT55 significantly reduced DNFB-induced DTH and attenuated inflammation, cartilage degradation, and bone destruction in CIA mice. Moreover, ZT55 was found to inhibit the proliferation and activation of T cells and the maturation of dendritic cells by regulating the JAK2-STAT3 signaling pathway. These results suggest that selectively targeting the JAK2 isoform could have anti-inflammatory and immunosuppressive effects by regulating the adaptive and innate immune responses via the JAK2-STAT3 signaling pathway. Therefore, ZT55 has the potential to be a promising pharmaceutical candidate for the treatment of inflammatory and autoimmune diseases.

Bone-derived MSCs encapsulated in alginate hydrogel prevent collagen-induced arthritis in mice through the activation of adenosine A2A/2B receptors in tolerogenic dendritic cells.

Tolerogenic dendritic cells (tolDCs) facilitate the suppression of autoimmune responses by differentiating regulatory T cells (Treg). The dysfunction of immunotolerance results in the development of autoimmune diseases, such as rheumatoid arthritis (RA). As multipotent progenitor cells, mesenchymal stem cells (MSCs), can regulate dendritic cells (DCs) to restore their immunosuppressive function and prevent disease development. However, the underlying mechanisms of MSCs in regulating DCs still need to be better defined. Simultaneously, the delivery system for MSCs also influences their function. Herein, MSCs are encapsulated in alginate hydrogel to improve cell survival and retention in situ, maximizing efficacy in vivo. The three-dimensional co-culture of encapsulated MSCs with DCs demonstrates that MSCs can inhibit the maturation of DCs and the secretion of pro-inflammatory cytokines. In the collagen-induced arthritis (CIA) mice model, alginate hydrogel encapsulated MSCs induce a significantly higher expression of CD39+CD73+ on MSCs. These enzymes hydrolyze ATP to adenosine and activate A2A/2B receptors on immature DCs, further promoting the phenotypic transformation of DCs to tolDCs and regulating naïve T cells to Tregs. Therefore, encapsulated MSCs obviously alleviate the inflammatory response and prevent CIA progression. This finding clarifies the mechanism of MSCs-DCs crosstalk in eliciting the immunosuppression effect and provides insights into hydrogel-promoted stem cell therapy for autoimmune diseases.

Celastrol Targets Cullin-Associated and Neddylation-Dissociated 1 to Prevent Fibroblast-Myofibroblast Transformation against Pulmonary Fibrosis.

Celastrol (CEL), a pentacyclic triterpene compound, has been proven to have a definite antipulmonary fibrosis effect. However, its direct targets for antipulmonary fibrosis remain unknown. In this study, we designed and synthesized a series of celastrol-based probes to identify the direct targets in human pulmonary fibroblasts using an activity-based protein profiling strategy. Among many fished targets, we identified a key protein, cullin-associated and neddylation-dissociated 1 (CAND1), which was involved in fibroblast-myofibroblast transformation (FMT). More importantly, we found that the inhibitory effect of celastrol on FMT is dependent on CAND1, through improving the interactions between CAND1 and Cullin1 to promote the activity of Skp1/Cullin1/F-box ubiquitin ligases. In silico studies and cysteine mutation experiments further demonstrated that Cys264 of CAND1 is the site for conjugation of celastrol. This reveals a new mechanism of celastrol against pulmonary fibrosis and may provide a novel therapeutic option for antipulmonary fibrosis.

A highly selective JAK3 inhibitor is developed for treating rheumatoid arthritis by suppressing γc cytokine-related JAK-STAT signal.

Janus kinases (JAKs) play a critical role in immune responses by relaying signals from more than 50 cytokines, making them attractive therapeutic targets for autoimmune diseases. Although approved JAK inhibitors have demonstrated clinical efficacy, they target a broad spectrum of cytokines, which results in side effects. Therefore, next-generation inhibitors maintain efficacy, while sparing adverse events need to be developed. Among members of the JAK family, JAK3 only regulates a narrow spectrum of γc cytokines and becomes a potentially ideal target. Here, a highly JAK3-selective inhibitor Z583 is developed, which showed a potent inhibition of JAK3 with an IC50 of 0.1 nM and exhibited a 4500-fold selectivity for JAK3 than other JAK subtypes. Furthermore, Z583 completely inhibited the γc cytokine signaling and sufficiently blocked the development of inflammatory response in RA model, while sparing hematopoiesis. Collectively, the highly selective JAK3 inhibitor Z583 is a promising candidate with significant therapeutic potential for autoimmune diseases.

Quercetin Impedes Th17 Cell Differentiation to Mitigate Arthritis Involving PPARγ-Driven Transactivation of SOCS3 and Redistribution Corepressor SMRT from PPARγ to STAT3.

SCOPE: Quercetin (QU) is one of the most abundant flavonoids in plants and has attracted the attention of researchers because of its remarkable antirheumatoid arthritis (RA) effects and extremely low adverse reactions. However, the underlying mechanism needs further study. METHODS AND RESULTS: Flow cytometry, immunofluorescence, enzyme linked immunosorbent assay （ELISA）, and quantitative real-time polymerase chain reaction （qRT-PCR） reveal the obvious inhibitory effects of QU on Th17 cell differentiation in arthritic mice. More importantly, QU markedly limits the development of Th17 cell polarization, which is virtually compromised by the treatment with peroxisome proliferator activated receptor γ (PPARγ) inhibitor GW9662 and knockdown of PPARγ. Additionally, molecular dynamics simulation and immunofluorescence exhibit QU directly binds to PPARγ and increases PPARγ nuclear translocation. Besides, QU confers its moderation effect on suppressor of cytokine signaling protein (SOCS3)/signal transducer and activator of transcription 3 (STAT3) axis partially depending on PPARγ. Furthermore, coimmunoprecipitation shows QU redistributes the corepressor silencing mediator for retinoid and thyroid-hormone receptors (SMRT) from PPARγ to STAT3. Finally, the inhibition of Th17 response and the antiarthritic effect of QU are nullified by GW9662 treatment in arthritic mice. CONCLUSION: QU targets PPARγ and consequently inhibits Th17 cell differentiation by dual inhibitory activity of STAT3 to exert antiarthritic effect. The findings facilitate its development and put forth a stage for uncovering the mechanism of other naturally occurring compounds with chemical structures similar to QU.

JAK3 inhibitors for the treatment of inflammatory and autoimmune diseases: a patent review (2016-present).

INTRODUCTION: Up to now, a total of eight Janus kinase (JAK) inhibitors have been approved for the treatment of autoimmune and myeloproliferative disease. The JAK family belongs to the non-receptor tyrosine kinase family, consisting of JAK1, JAK2, JAK3, and Tyk2. Among these four subtypes, only JAK3 is mainly expressed in hematopoietic tissue cells and is exclusively associated with the cytokines shared in the common gamma-chain receptor subunit. Due to its specific tissue distribution and functional characteristics that distinguish it from the other JAKs family subtypes, JAK3 is a promising target for the treatment of autoimmune disease. AREAS COVERED: This study aimed to provide a comprehensive review of the available patent literature on JAK-family inhibitors published from 2016 to the present. In addition, an overview of the clinical activities of selective JAK3 inhibitors in recent years was provided. EXPERT OPINION: To date, no selective JAK3 inhibitors have been approved for use in clinics. Over the last 5 years, an increasing number of studies on JAK3 inhibitors, particularly ritlecitinib by Pfizer, have demonstrated their promising therapeutic potential. In this review, recent studies reported that selective JAK3 inhibitors may offer valid, interesting, and promising therapeutic potential in inflammatory and autoimmune diseases.

Studies of Interaction Mechanism between Pyrido [3,4-d] Pyrimidine Inhibitors and Mps1.

Monopolar spindle 1 (Mps1), a dual-specific kinase, is related to the proper execution of chromosome biorientation and mitotic checkpoint signaling. The overexpression of Mps1 promotes the occurrence of cancer or the survival of aneuploid cancer cells, in other words, the reduction of Mps1 will severely reduce the viability of human cancer cells. Therefore, Mps1 is a potential target for cancer treatment. Recently, a series of novel pyrido [3,4-d] pyrimidine derivatives targeting Mps1 with high biological activity were synthesized. The crystal structure of Mps1 in complex with pyrido [3,4-d] pyrimidine derivatives was also reported, but there were no specific mechanism studies for this series of small molecule inhibitors. In this study, complexes binding modes were probed by molecular docking and further validated by molecular dynamics simulations and the molecular mechanics/generalized Born surface area (MM/GBSA) method. The results indicated that the van der Waals interactions and the nonpolar solvation energies were responsible to the basis for favorable binding free energies, all inhibitors interacted with residues I531, V539, M602, C604, N606, I607, L654, I663, and P673 of Mps1. By analyzing the hydrogen bonds, we found the residues G605 and K529 in Mps1 formed stable hydrogen bonds with compounds, it was more conducive to activities of Mps1 inhibitors. According to the above analysis, we further designed five new compounds. We found that compounds IV and V were better potential Mps1 inhibitors through docking and ADMET prediction. The obtained new insights not only were helpful in understanding the binding mode of inhibitors in Mps1, but also provided important references for further rational design of Mps1 inhibitors.

Divanillyl sulfone suppresses NLRP3 inflammasome activation via inducing mitophagy to ameliorate chronic neuropathic pain in mice.

BACKGROUND: Chronic neuropathic pain is a frequent sequel to peripheral nerve injury and maladaptive nervous system function. Divanillyl sulfone (DS), a novel structural derivative of 4,4'-dihydroxydibenzyl sulfoxide from a traditional Chinese medicine Gastrodia elata with anti-nociceptive effects, significantly alleviated neuropathic pain following intrathecal injection. Here, we aimed to investigate the underlying mechanisms of DS against neuropathic pain. METHODS: A chronic constrictive injury (CCI) mouse model of neuropathic pain induced by sciatic nerve ligation was performed to evaluate the effect of DS by measuring the limb withdrawal using Von Frey filament test. Immunofluorescence staining was used to assess the cell localizations and expressions of Iba-1, ASC, NLRP3, and ROS, the formation of autolysosome. The levels of NLRP3-related proteins (caspase-1, NLRP3, and IL-1ß), mitophagy-related proteins (LC3, Beclin-1, and p62), and apoptosis-related proteins (Bcl-XL and Bax) were detected by Western blotting. The apoptosis of BV-2 cell and caspase activity were evaluated by flow cytometry. RESULTS: DS significantly alleviated the neuropathic pain by increasing the mechanical withdrawal threshold and inhibiting the activation of NLRP3 in CCI-induced model mice. Our findings indicated that DS promoted the mitophagy by increasing the LC3II and Beclin 1 and decreasing the levels of p62 protein in BV-2 cell. This is accompanied by the inhibition of NLRP3 activation, which was shown as inhibited the expression of NLRP3 in lysates as well as the secretion of mature caspase-1 p10 and IL-1ß p17 in supernatants in cultured BV-2 microglia. In addition, DS could promote mitophagy-induced improvement of dysfunctional mitochondria by clearing intracellular ROS and restoring mitochondrial membrane potential. CONCLUSION: Together, our findings demonstrated that DS ameliorate chronic neuropathic pain in mice by suppressing NLRP3 inflammasome activation induced by mitophagy in microglia. DS may be a promising therapeutic agent for chronic neuropathic pain.

Therapeutic potential of the target on NLRP3 inflammasome in multiple sclerosis.

Inflammasomes are multi-protein macromolecular complexes that typically comprise of three units, a sensor, an adaptor and procaspase-1. The assembly of each inflammasome is dictated by a unique pattern recognition receptors (PRRs) in response to pathogen-associated molecular patterns (PAMPs) or other endogenous danger-associated molecular patterns (DAMPs) in the cytosol of the host cells, and promote the maturation and secretion of IL-1ß and IL-18 during the inflammatory process. Specific inflammasomes are involved in the host defense response against different pathogens, and the latter have evolved multiple corresponding mechanisms to inhibit inflammasome activation. The nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain-containing 3 (NLRP3) inflammasome is the best understood in terms of molecular mechanisms, and is a promising therapeutic target in immune-related disorders. Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory demyelination of white matter in the central nervous system, increased levels of IL-1ß in the cerebrospinal fluid (CSF) of relapsed patients, and deposition of caspase-1 in the spinal cord. The direct involvement of the NLRP3 inflammasome in the occurrence and development of MS was ascertained in the experimental autoimmune encephalomyelitis (EAE) animal model. In this review, we have focused on the mechanisms underlying activation of the NLRP3 inflammasome in MS or EAE, as well as inhibitors that specifically target the complex and alleviate disease progression, in order to unearth new therapeutic strategies against MS.

Emerging small-molecule inhibitors of the Bruton's tyrosine kinase (BTK): Current development.

Therapy based on Bruton's tyrosine kinase (BTK) inhibitors one of the major treatment options currently recommended for lymphoma patients. The first generation of BTK inhibitor, Ibrutinib, achieved remarkable progress in the treatment of B-cell malignancies, but still has problems with drug-resistance or off-target induced serious side effects. Therefore, numerous new BTK inhibitors were developed to address this unmet medical need. In parallel, the effect of BTK inhibitors against immune-related diseases has been evaluated in clinical trials. This review summarizes recent progress in the research and development of BTK inhibitors, with a focus on structural characteristics and structure-activity relationships. The structure-refinement process of representative pharmacophores as well as their effects on binding affinity, biological activity and pharmacokinetics profiles were analyzed. The advantages and disadvantages of reversible/irreversible BTK inhibitors and their potential implications were discussed to provide a reference for the rational design and development of novel potent BTK inhibitors.

Exploring a novel triptolide derivative possess anti-colitis effect via regulating T cell differentiation.

Inflammatory bowel disease (IBD) is generally characterized by chronic inflammatory disorders of the gastrointestinal tract that are known as ulcerative colitis (UC) or Crohn's disease (CD). Although the underlying mechanism of action of IBD is unclear and because of the lack of satisfactory treatment, increasing evidence has indicated that pro-inflammatory cytokines that activate JAK-STAT signaling pathway regulate the differentiation of naïve T cells towards T helper (Th)1 and Th17 cell subsets and contribute to the development of IBD. ZT01 is a newly obtained triptolide derivative with strong anti-inflammatory effects and low toxicity. In this study, we evaluated the effects of ZT01 on DSS-induced colitis and investigated the underlying mechanism of action involved. Mice with DSS-induced acute or chronic colitis were used to assess the efficacy of ZT01 treatment, and T cells were cultured to analyze the differentiation of Th1 and Th17 cell by flow cytometry. In addition, intestinal epithelial barrier function, macrophage polarization, activation of the JAK-STAT signaling pathway, and the expression of cytokines and transcription factors were measured to assess the possible mechanisms of ZT01. We found that ZT01 had an obviously beneficial effect on DSS-induced colitis by improving the symptoms of bloody diarrhea, weight loss, and a shortened colon, thereby preserving the epithelial barrier function in the mouse colon. Furthermore, ZT01 significantly inhibited T cell differentiation into Th1 and/or Th17 cell subsets and macrophage polarization towards into an inflammatory phenotype via regulating the JAK-STAT signaling pathway. Thus, our findings suggested that ZT01 might be a potential pharmaceutical candidate that deserves to be further investigated as a treatment for IBD patients.

Methotrexate enhances antigen presentation and maturation of tumour antigen-loaded dendritic cells through NLRP3 inflammasome activation: a strategy for dendritic cell-based cancer vaccine.

BACKGROUND: Dendritic cells (DCs) are antigen-presenting cells that play a pivotal role in adaptive cell-mediated immunity by priming and activating T cells against specific tumour and pathogenic antigens. Methotrexate (MTX), a folate derivative, functions as an immunoregulatory agent. However, the possible effect of MTX on tumour antigen-loaded DCs has not yet been investigated. METHODS: We analysed the effect of MTX on the maturation and function of DCs along with tumour cell lysates (TCLs). Using bone marrow-derived DCs, we investigated the effect of MTX combined TCL-loaded DCs on T cells priming and proliferation. We also tested the anti-tumour immune effect on DCs when treated with MTX and/or TCL in vivo. RESULTS: MTX combined with TCL not only enhanced DC maturation and stimulated cytokine release but also promoted CD8+ T cell activation and proliferation. The latter was associated with increased tumour antigen uptake and cross-presentation to T cells. Mechanistically, DC maturation and antigen presentation were partly modulated by NLRP3 inflammasome activation. Furthermore, immunisation of mice with MTX and TCL-pulsed DCs before a tumour challenge significantly delayed tumour onset and retarded its growth. This protective effect was due to priming of IFN-γ releasing CD8+ T cells and enhanced killing of tumour cells by cytotoxic T lymphocytes isolated from these immunised mice. CONCLUSION: MTX can function as a potent adjuvant in DC vaccines by increasing antigen presentation and T cell priming. Our findings provide a new strategy for the application of DC-based anti-tumour immunotherapy.

Novel 1H-pyrazolo[3,4-d]pyrimidin-6-amino derivatives as potent selective Janus kinase 3 (JAK3) inhibitors. Evaluation of their improved effect for the treatment of rheumatoid arthritis.

Selective JAK3 inhibitors have been shown to have a potential benefit in the treatment of autoimmune disorders. Here we report the identification of a series of pyrazolopyrimidine derivatives as potent JAK3 inhibitors that exploit a unique cysteine (Cys909) residue in JAK3. Most of these compounds (13k, 13n and 13 t), displayed stronger anti-JAK3 kinase activity and selectivity than tofacitinib. Furthermore, the most active inhibitor 13t (IC50 = 0.1 nM), also exhibited favourable selectivity for JAK3 in a panel of 9 kinases which contain the same cysteine. In a series of cytokinestimulated cellular analysis, compound 13 t, could potently block the JAK3-STAT signaling pathway. Further biological studies, including cellular antiproliferative activity assays and a rat adjuvant-induced arthritis model for in vivo evaluation, also indicated its efficacy and low toxicity in the treatment of rheumatoid arthritis. The results of these experimental explorations suggested that 13t is a promising lead compound for the development of selective JAK3 inhibitor with therapeutic potential in rheumatoid arthritis.

A novel triptolide derivative ZT01 exerts anti-inflammatory effects by targeting TAK1 to prevent macrophage polarization into pro-inflammatory phenotype.

Sepsis is a main reason for death in intensive care units, inflammation is closely related to sepsis. Anti-inflammation plays an important role in treating of sepsis. ZT01 is a triptolide derivative with strong anti-inflammatory activity and low toxicity. The purpose of this study is to evaluate the anti-inflammatory activity of ZT01 under the sepsis condition and explore the underlying molecular mechanisms. Two in vivo model of sepsis, caecal ligation and puncture or intraperitoneal injection of LPS in C57BL/6, were used to evaluate the therapeutic effects of ZT01. In vitro, the anti-inflammatory properties of ZT01 were assessed in IFN-γ or LPS-induced macrophages by ELISA, RT-PCR, western blotting and co-immunoprecipitation. Macrophages were used to investigate the polarization phenotype by flow cytometry. The results showed, ZT01 significantly attenuated inflammatory response of sepsis in serum or lung tissue by inhibiting production of pro-inflammatory factors and improved the survival rate of septic mice in vivo. In cultured macrophages, ZT01 not only decreased the levels of TNF-α and IL-6 but also prevented the TKA1-TAB1 complex formation, thereby inhibiting the phosphorylation expression of MKK4 and JNK, which were all stimulated by LPS. Moreover, ZT01 inhibited the LPS-induced polarization of macrophages into pro-inflammatory phenotype. Adoptive transfer ZT01 pretreated bone marrow-derived macrophages obviously reduced the pro-inflammatory factors in mice after LPS challenge. Our findings suggested that ZT01 exhibited anti-inflammation activity via preventing the pro-inflammatory phenotype of macrophages by blocking the formation of the TAK1-TAB1 complex and subsequently phosphorylation of MKK4 and JNK.

Novel nitric oxide-releasing derivatives of triptolide as antitumor and anti-inflammatory agents: Design, synthesis, biological evaluation, and nitric oxide release studies.

A series of novel triptolide/furoxans hybrids were designed and synthesized as analogues of triptolide, which is a naturally derived compound isolated from the thunder god vine (Tripterygium wilfordii Hook. F). Some of these synthesized compounds exhibited antiproliferative activities in the nanomolar range. Among them, compound 33 exhibited both good antiproliferative activity and NO-releasing ability and the acute toxicity of compound 33 decreased more than 160 times (LD50 = 160.9 mg/kg) than triptolide. Moreover, compound 33 significantly inhibited the growth of melanoma at a low dose (0.3 mg/kg) and showed strong anti-inflammatory activity in vitro and in vivo. These results indicate that compound 33 could be a promising candidate for further study.

Design, synthesis, and pharmacological evaluation of 4- or 6-phenyl-pyrimidine derivatives as novel and selective Janus kinase 3 inhibitors.

As non-receptor tyrosine kinases, Janus kinases (JAKs) have become an attractive target for the treatment of autoimmune diseases and cancers. JAKs play a pivotal role in innate immunity, inflammation, and hematopoiesis by mediating the signaling of numerous cytokines, growth factors, and interferons (IFNs). Selective inhibitors of a variety of JAK members are expected to inhibit pro-inflammatory cytokine-mediated inflammation and immune responses, while preventing targeting other subtypes of JAKs. In this work, poorly selective compounds based on 4- or 6-phenyl-pyrimidine derivatives have been improved to highly potent and selective compounds by designing a covalent binding tether, which attaches to the unique cysteine (Cys909) residue in JAK3. Compound 12 exhibited potent JAK3 inhibitory activity (IC50 = 1.7 nM) with an excellent selectivity profile when compared to the other JAK isoforms (>588-fold). In a cellular assay, compound 12 strongly inhibited JAK3-dependent signaling and T cell proliferation. Moreover, in vivo data revealed that compound 12 significantly suppressed oxazolone (OXZ)-induced delayed hypersensitivity responses in Balb/c mice. Compound 12 also displayed decent pharmacokinetic properties and was suitable for in vivo use. Taken together, these results indicated that compound 12 may be a promising tool compound as a selective JAK3 inhibitor for treating autoimmune diseases.

Isotalatizidine, a C19-diterpenoid alkaloid, attenuates chronic neuropathic pain through stimulating ERK/CREB signaling pathway-mediated microglial dynorphin A expression.

BACKGROUND: Isotalatizidine is a representative C19-diterpenoid alkaloid extracted from the lateral roots of Aconitum carmichaelii, which has been widely used to treat various diseases on account of its analgesic, anti-inflammatory, anti-rheumatic, and immunosuppressive properties. The aim of this study was to evaluate the analgesic effect of isotalatizidine and its underlying mechanisms against neuropathic pain. METHODS: A chronic constrictive injury (CCI)-induced model of neuropathic pain was established in mice, and the limb withdrawal was evaluated by the Von Frey filament test following isotalatizidine or placebo administration. The signaling pathways in primary or immortalized microglia cells treated with isotalatizidine were analyzed by Western blotting and immunofluorescence. RESULTS: Intrathecal injection of isotalatizidine attenuated the CCI-induced mechanical allodynia in a dose-dependent manner. At the molecular level, isotalatizidine selectively increased the phosphorylation of p38 and ERK1/2, in addition to activating the transcription factor CREB and increasing dynorphin A production in cultured primary microglia. However, the downstream effects of isotalatizidine were abrogated by the selective ERK1/2 inhibitor U0126-EtOH or CREB inhibitor of KG-501, but not by the p38 inhibitor SB203580. The results also were confirmed in in vivo experiments. CONCLUSION: Taken together, isotalatizidine specifically activates the ERK1/2 pathway and subsequently CREB, which triggers dynorphin A release in the microglia, eventually leading to its anti-nociceptive action.

Machine Learning Models Based on Molecular Fingerprints and an Extreme Gradient Boosting Method Lead to the Discovery of JAK2 Inhibitors.

Developing Janus kinase 2 (JAK2) inhibitors has become a significant focus for small-molecule drug discovery programs in recent years because the inhibition of JAK2 may be an effective approach for the treatment of myeloproliferative neoplasm. Here, based on three different types of fingerprints and Extreme Gradient Boosting (XGBoost) methods, we developed three groups of models in that each group contained a classification model and a regression model to accurately acquire highly potent JAK2 kinase inhibitors from the ZINC database. The three classification models resulted in Matthews correlation coefficients of 0.97, 0.94, and 0.97. Docking methods including Glide and AutoDock Vina were employed to evaluate the virtual screening effectiveness of our classification models. The R2 of three regression models were 0.80, 0.78, and 0.80. Finally, 13 compounds were biologically evaluated, and the results showed that the IC50 values of six compounds were identified to be less than 100 nM. Among them, compound 9 showed high activity and selectivity in that its IC50 value was less than 1 nM against JAK2 while 694 nM against JAK3. The strategy developed may be generally applicable in ligand-based virtual screening campaigns.

Discovery of novel selective Janus kinase 2 (JAK2) inhibitors bearing a 1H-pyrazolo[3,4-d]pyrimidin-4-amino scaffold.

Janus kinases (JAKs) regulate various cancers and immune responses and are targets for the treatment of cancers and immune diseases. A new series of 1H-pyrazolo[3,4-d]pyrimidin-4-amino derivatives were synthesized and optimized by introducing a functional 3,5-disubstituted-1H-pyrazole moiety into the C-3 moiety of pyrazole template, and then were biologically evaluated as potent Janus kinase 2 (JAK2) inhibitors. Among these molecules, inhibitors 11f, 11g, 11h and 11k displayed strong activity and selectivity against the JAK2 kinase, with IC50 values of 7.2 nM, 6.5 nM, 8.0 nM and 9.7 nM, respectively. In particular, the cellular inhibitory assay and western blot analysis further support the JAK2 selectivity of compound 11g also in cells. Furthermore, compound 11g also exhibited potent inhibitory activity in lymphocytes proliferation assay and delayed hypersensitivity assay. Taken together, the novel JAK2 selective inhibitors discovered in this study may be potential lead compounds for new drug discovery via further development of more potent and selective JAK2 inhibitors.