Anti-inflammatory effects of Morus alba Linne bark on the activation of toll-like receptors and imiquimod-induced ear edema in mice

A new MAS-related G protein-coupled receptor X2 cell membrane chromatography analysis model based on HALO-tag technology and its applications

Cell membrane chromatography (CMC) is an effective method for studying receptors with multiple transmembrane structure such as MAS-related G protein-coupled receptor X2 (MrgX2). CMC relies on the maintenance of the complete biological structure of a membrane receptor; however, it needs to be further improved to obtain a more convenient and stable CMC model. In the present study, the haloalkane dehalogenase protein tag (HALO-tag) technology was used to construct a new MrgX2/CMC model. The fusion receptors of MrgX2 with HALO-tag at the C terminus were expressed in HEK293 cells. The silica gel was modified with a substrate of HALO-tag (chloroalkanes) via one-step acylation for the rapid capture of fusion receptors. The new CMC model (MrgX2-HALO-tag/CMC model) was not only quicker to prepare but also more stable and had a longer lifespan than a previous MrgX2-SNAP-tag/CMC model. In combination with the high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) system, the MrgX2-HALO-tag/CMC model was used to screen and identify bioactive components in traditional Chinese medicine. Using this combination, sanggenon C and morusin were identified from Mori Cortex as anti-pseudo-allergic components. The MrgX2-HALO-tag/CMC model alone was also applied to analyze ligand-receptor interaction. The affinity order of four ligands to MrgX2 was as follows: desipramine < imipramine < amitriptyline < clomipramine. This was consistent with the results obtained using the MrgX2-SNAP-tag/CMC model. The MrgX2-HALO-tag/CMC model provides ideas and application prospects for the immobilization of cell membrane that contains receptors with more transmembrane structures.

Piper retrofractum ameliorates imiquimod-induced skin inflammation via modulation of TLR4 axis and suppression of NF-κB activity

Chronic inflammation is a significant concern due to its association with various pathological conditions. As a result, extensive research has been conducted to identify new natural products that can effectively treat acute inflammation, which has the potential to inhibit the chronic inflammation. In our study, we aimed to identify Indonesian medicinal plants with the ability to inhibit proinflammatory agents, specifically targeting NF-κB, a crucial regulator of gene transcription involved in the production of proinflammatory proteins/cytokines. Through a series of identification processes, we found that Piper retrofractum (Javanese chili) extract demonstrated promising inhibitory effects on NF-κB and proinflammatory molecules. Further investigation was conducted using a variety of assays, including reporter assay, viability test, ELISA, and Western blotting. The results revealed that the extract significantly reduced LPS, NO, COX-2, IL-6, IL-1, and NF-κB through the TLR4 axis. Notably, Piper retrofractum extract was found to enhance the survival of human keratinocytes by protecting them from cell death induced by TRAIL, a member of the TNF superfamily. Moreover, immunohistochemistry analysis in an Imiquimod-induced skin inflammation mice model showed downregulation of COX-2 and IL-1β expression upon treatment with the extract. In conclusion, our findings suggest that Piper retrofractum extract possesses anti-inflammatory properties by reducing proinflammatory cytokine production through inhibition of NF-κB signaling pathway. These promising results highlight the potential of Piper retrofractum extract as a candidate for future drug development in the clinical treatment of inflammation-related conditions, offering hope for the advancement of therapeutic interventions.

Morus alba fruits attenuates atopic dermatitis symptoms and pathology in vivo and in vitro via the regulation of barrier function, immune response and pruritus

BACKGROUND

Morus alba fruits (MAF) belong to the Moraceae family, which are known to be effective in treating diabetic, autoimmune, and hormonal diseases owing to its low toxicity. MAF, as excerpted from Donguibogam, a representative Korean medical encyclopedia protected by UNESCO, has been widely used to treat lumbago, arthritis, and diabetes. Based on these effects, MAF is investigated for unidentified effects of atopic dermatitis, characterized by complex etiology of skin barrier dysfunction, inflammation, and chronic pruritus.

METHODS

The antioxidant, inflammatory, and immunomodulatory properties of MAF and its bioactive compounds have been widely reported. According to an examination of 1-chloro-2,4-dinitrobenzene-induced AD-like skin lesions in NC/Nga mice, AD symptoms, such as increased dermatitis score, scratching frequency, immunoglobulin E, trans-epidermal water loss, epidermal thickness, and infiltration of mast cells, were relieved by topical MAF administration. They effectively attenuated cytokines and chemokines, such as interleukin (IL)-4, IL-5, IL-6, IL-8, IL-13, IL-17A, IL-22, IL-1β, tumor necrosis factor-α, thymic stromal lymphopoietin (TSLP), thymic- and activation-regulated chemokine, normal T cell expression, and macrophage-derived chemokine secretion at the mRNA level in TNF-α/IFN-γ induced HaCaT (human immortalized keratinocyte) cells.

RESULTS

Both in vivo and in vitro models, MAF increased the expression of filaggrin, involucrin, and loricrin, as well as inhibited the activation of Janus kinase 2, signal transducer and activator of transcription proteins 1, and mitogen-activated protein kinase pathways, including extracellular signal-regulated kinase, c-jun N-terminal kinase, and p38. Moreover, MAF reduced the expression of TSLP and periostin, which play important roles in skin pruritus as chronic pruritogenic factors.

CONCLUSION

These data indicate that MAF could be used as a potential treatment for AD-like skin lesions by regulating the inflammatory response, improving physical skin barriers, and relieving symptomatic pruritus.

Dendritic Cells and CCR7 Expression: An Important Factor for Autoimmune Diseases, Chronic Inflammation, and Cancer

Chemotactic cytokines-chemokines-control immune cell migration in the process of initiation and resolution of inflammatory conditions as part of the body's defense system. Many chemokines also participate in pathological processes leading up to and exacerbating the inflammatory state characterizing chronic inflammatory diseases. In this review, we discuss the role of dendritic cells (DCs) and the central chemokine receptor CCR7 in the initiation and sustainment of selected chronic inflammatory diseases: multiple sclerosis (MS), rheumatoid arthritis (RA), and psoriasis. We revisit the binary role that CCR7 plays in combatting and progressing cancer, and we discuss how CCR7 and DCs can be harnessed for the treatment of cancer. To provide the necessary background, we review the differential roles of the natural ligands of CCR7, CCL19, and CCL21 and how they direct the mobilization of activated DCs to lymphoid organs and control the formation of associated lymphoid tissues (ALTs). We provide an overview of DC subsets and, briefly, elaborate on the different T-cell effector types generated upon DC-T cell priming. In the conclusion, we promote CCR7 as a possible target of future drugs with an antagonistic effect to reduce inflammation in chronic inflammatory diseases and an agonistic effect for boosting the reactivation of the immune system against cancer in cell-based and/or immune checkpoint inhibitor (ICI)-based anti-cancer therapy.