Phenotypic Screening-Based Identification of 3,4-Disubstituted Piperidine Derivatives as Macrophage M2 Polarization Modulators: An Opportunity for Treating Multiple Sclerosis

Discovery of Novel Azaindoles as Potent and Selective PI3Kδ Inhibitors for Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disorder of the central nervous system and the unmet need for MS treatment demands new therapeutic development. Particularly, PI3Kδ is a high-value target for autoimmune disease, while the investigation of PI3Kδ inhibitors for MS therapy is relatively scarce. Herein, we report a novel class of azaindoles as PI3Kδ inhibitors for MS treatment. Compound 31, designed via nitrogen bioisosterism, displayed excellent PI3Kδ inhibitory activity and selectivity. In vitro assay showed that 31 exhibited superior activity on T lymphocytes to inhibit the proliferation of CD4+, CD8+, and CD3+ T cells. In the experimental autoimmune encephalomyelitis (EAE) model, 31 showed a comparable therapeutical efficacy with Dexamethasone to significantly ameliorate EAE symptoms. Mechanistic studies showed that compound 31 could significantly inhibit the PI3K/AKT/mTOR signaling pathway and inhibited T-cell proliferation and differentiation. Overall, this work provides a new structural PI3Kδ inhibitor and a new vision for MS therapy.

Macrophage polarization: an important role in inflammatory diseases

Macrophages are crucial cells in the human body's innate immunity and are engaged in a variety of non-inflammatory reactions. Macrophages can develop into two kinds when stimulated by distinct internal environments: pro-inflammatory M1-like macrophages and anti-inflammatory M2-type macrophages. During inflammation, the two kinds of macrophages are activated alternatively, and maintaining a reasonably steady ratio is critical for maintaining homeostasis in vivo. M1 macrophages can induce inflammation, but M2 macrophages suppress it. The imbalance between the two kinds of macrophages will have a significant impact on the illness process. As a result, there are an increasing number of research being conducted on relieving or curing illnesses by altering the amount of macrophages. This review summarizes the role of macrophage polarization in various inflammatory diseases, including autoimmune diseases (RA, EAE, MS, AIH, IBD, CD), allergic diseases (allergic rhinitis, allergic dermatitis, allergic asthma), atherosclerosis, obesity and type 2 diabetes, metabolic homeostasis, and the compounds or drugs that have been discovered or applied to the treatment of these diseases by targeting macrophage polarization.

Lapachol inhibits the growth of lung cancer by reversing M2-like macrophage polarization via activating NF-κB signaling pathway

Resetting tumor-associated macrophages (TAMs) is a promising strategy to ameliorate the immunosuppressive tumor microenvironment (TME) and improve innate and adaptive antitumor immunity. Lapachol, a naturally occurring 1,4-naphthoquinone, exhibits various pharmacological activities including antitumor, anti-leishmanial, antimalarial and antiseptic. In this study, we investigated the relevance of macrophage polarization and the antitumor effect of lapachol in Lewis lung cancer (LLC) both in vitro and in vivo. This study demonstrated that lapachol significantly reversed the polarization of M2-like macrophages thus that were endowed with the ability to kill LLC cells by activating NF-κB signaling pathway. Furthermore, lapachol effectively suppressed tumor growth in C57BL/6 mice bearing lung tumors by reducing the proportion of M2-like macrophages. Overall, our findings clearly illustrated that lapachol could reverse the polarization of M2-like macrophages to improve the immunosuppressive tumor microenvironment, and had the potential to be developed as an immunomodulatory antitumor agent.

miR-124: A Promising Therapeutic Target for Central Nervous System Injuries and Diseases

Central nervous system injuries and diseases, such as ischemic stroke, spinal cord injury, neurodegenerative diseases, glioblastoma, multiple sclerosis, and the resulting neuroinflammation often lead to death or long-term disability. MicroRNAs are small, non-coding, single-stranded RNAs that regulate posttranscriptional gene expression in both physiological and pathological cellular processes, including central nervous system injuries and disorders. Studies on miR-124, one of the most abundant microRNAs in the central nervous system, have shown that its dysregulation is related to the occurrence and development of pathology within the central nervous system. Herein, we review the molecular regulatory functions, underlying mechanisms, and effective delivery methods of miR-124 in the central nervous system, where it is involved in pathological conditions. The review also provides novel insights into the therapeutic target potential of miR-124 in the treatment of human central nervous system injuries or diseases.

Physiologic Targets and Modes of Action for CBL0137, a Lead for Human African Trypanosomiasis Drug Development

CBL0137 is a lead drug for human African trypanosomiasis, caused by Trypanosoma brucei Herein, we use a four-step strategy to 1) identify physiologic targets and 2) determine modes of molecular action of CBL0137 in the trypanosome. First, we identified fourteen CBL0137-binding proteins using affinity chromatography. Second, we developed hypotheses of molecular modes of action, using predicted functions of CBL0137-binding proteins as guides. Third, we documented effects of CBL0137 on molecular pathways in the trypanosome. Fourth, we identified physiologic targets of the drug by knocking down genes encoding CBL0137-binding proteins and comparing their molecular effects to those obtained when trypanosomes were treated with CBL0137. CBL0137-binding proteins included glycolysis enzymes (aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphofructokinase, phosphoglycerate kinase) and DNA-binding proteins [universal minicircle sequence binding protein 2, replication protein A1 (RPA1), replication protein A2 (RPA2)]. In chemical biology studies, CBL0137 did not reduce ATP level in the trypanosome, ruling out glycolysis enzymes as crucial targets for the drug. Thus, many CBL0137-binding proteins are not physiologic targets of the drug. CBL0137 inhibited 1) nucleus mitosis, 2) nuclear DNA replication, and 3) polypeptide synthesis as the first carbazole inhibitor of eukaryote translation. RNA interference (RNAi) against RPA1 inhibited both DNA synthesis and mitosis, whereas RPA2 knockdown inhibited mitosis, consistent with both proteins being physiologic targets of CBL0137. Principles used here to distinguish drug-binding proteins from physiologic targets of CBL0137 can be deployed with different drugs in other biologic systems. SIGNIFICANCE STATEMENT: To distinguish drug-binding proteins from physiologic targets in the African trypanosome, we devised and executed a multidisciplinary approach involving biochemical, genetic, cell, and chemical biology experiments. The strategy we employed can be used for drugs in other biological systems.

Tanyu Tongzhi Formula Delays Atherosclerotic Plaque Progression by Promoting Alternative Macrophage Activation via PPARγ and AKT/ERK Signal Pathway in ApoE Knock-Out Mice

We previously demonstrated that the Tanyu Tongzhi Formula (TTF) significantly alleviated the clinical symptoms of patients with coronary heart disease and lowered serum lipid and inflammatory factor levels in patients with coronary heart disease and atherosclerosis model rats. However, the mechanism underlying TTF remains unknown. In this study, we examined the effect of TTF on atherosclerotic plaques in ApoE^-/- mice and underlying mechanisms involved in macrophage polarization. Sixty male ApoE^-/- mice were randomly divided into four groups. Mice in the control group were fed a regular diet, whereas experimental mice were fed a high-fat diet and received either saline (HFD group) or TTF at concentrations of 0.60 (TTF-L group) or 2.25 g/ml (TTF-H group) by daily oral gavage for 16 weeks. In the TTF-L and TTF-H groups, the levels of serum cholesterol, triglyceride, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α were decreased, lipid content was significantly decreased, and percentage area of collagen/lipid increased in atherosclerotic plaque compared to in the HFD group. Moreover, we found TTF promoted the expression of alternative macrophage markers (Fizz1, Arg1, and Mrc) and suppressed the expression of M1 macrophage markers (TNF-α, IL-1β, and IL-6) by regulating peroxisome proliferator-activated receptor γ (PPARγ) expression and AKT/extracellular signal-regulated kinase (ERK) activation. We further investigated whether alternative macrophage was reduced when PPARγ was inhibited or the AKT/ERK signaling pathway was activated. TTF delayed atherosclerotic plaque progression by promoting alternative macrophage activation through increasing PPARγ expression and inhibiting AKT/ERK phosphorylation, providing a theoretical basis for its clinical application.

Discovery of seneciobipyrrolidine derivatives for the amelioration of glucose homeostasis disorders through 4E-BP1/Akt/AMPK signaling activation

Modulating the glucose transport in skeletal muscle is a promising strategy for ameliorating glucose homeostasis disorders. However, the complicated mechanisms of glucose transport make it difficult to find compounds therapeutically relevant molecular mechanisms of action, while phenotypic screening is thought to be an alternative approach to mimic the cell state of interest. Here, we report (±)-seneciobipyrrolidine (1a) is first found to enhance glucose uptake in L6 myotubes through phenotype-based screening. Further SAR investigation led to the identfication of compound A27 (EC₅₀ = 2.7 μM). Proteomiic analysis discloses the unique function mechanism of A27 through upregulating the level of the eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), subsequently enhancing the Akt and AMPK phosphorylation, thereby promoting the glucose uptake. Chronic oral administration of A27 significantly lowers blood glucose and improves glucose tolerance in db/db mice. This work is new research on seneciobipyrrolidine derivatives, providing a promising avenue for ameliorating glucose homeostasis.

Discovery of 5,6-Bis(4-methoxy-3-methylphenyl)pyridin-2-amine as a WSB1 Degrader to Inhibit Cancer Cell Metastasis

The gain of cell motility is an essential prerequisite for cancer metastasis. The ubiquitin ligase subunit WD repeat and SOCS box-containing 1 (WSB1) has been demonstrated to regulate hypoxia-driven tumor cell migration. However, there is still a lack of methods for discovering inhibitors targeting the WSB1 axis. Here, we employed phenotypic screening models and identified compound 4 that displayed migration inhibitory activity against WSB1-overexpressing cells. Further studies indicated that it may function as a WSB1 degrader, thus leading to the accumulation of the Rho guanosine diphosphate dissociation inhibitor 2 (RhoGDI2) protein, reversing the expression of downstream F-actin and formation of membrane ruffles, and disturbing the migration capacity of cancer cells. Moreover, compound 4 exhibited a promising in vivo anticancer metastatic effects. Our findings show the discovery of a new WSB1 degrader, providing a unique solution for the treatment of cancer metastasis.

SCARF1 promotes M2 polarization of Kupffer cells via calcium-dependent PI3K-AKT-STAT3 signalling to improve liver transplantation

OBJECTIVES

This study aimed to investigate the protective effect of SCARF1 on acute rejection (AR), phagocytic clearance of Kupffer cells (KCs), M2 polarization and the exact mechanism underlying these processes.

METHODS

AAV was transfected into the portal vein of rats, and AR and immune tolerance (IT) models of liver transplantation were established. Liver tissue and blood samples were collected. The level of SCARF1 was detected via WB and immunohistochemical staining. Pathological changes in liver tissue were detected using HE staining. Apoptotic cells were detected using TUNEL staining. KC polarization was assessed via immunohistochemical staining. Primary KCs were isolated and co-cultured with apoptotic T lymphocytes. Phagocytosis of apoptotic cells and polarization of KCs were both detected using immunofluorescence. Calcium concentration was determined using immunofluorescence and a fluorescence microplate reader. The levels of PI3K, p-AKT and P-STAT3 were assessed via WB and immunofluorescence.

RESULTS

Compared to the IT group, the level of SCARF1 was significantly decreased in the AR group. Overexpression of SCARF1 in KCs improved AR and liver function markers. Enhanced phagocytosis mediated by SCARF1 is beneficial for improving the apoptotic clearance of AR and promoting M2 polarization of KCs. SCARF1-mediated enhancement of phagocytosis promotes increased calcium concentration in KCs, thus further activating the PI3K-AKT-STAT3 signalling pathway.

CONCLUSIONS

SCARF1 promotes the M2 polarization of KCs by promoting phagocytosis through the calcium-dependent PI3K-AKT-STAT3 signalling pathway.