Occludin is a key tight junction protein that contributes to epithelial barrier integrity and inflammatory regulation. Although its structural roles are well characterized, the physiological relevance of its C-terminal domain in airway inflammation remains poorly defined. Occludin expression was statistically reduced in inflamed human lung tissues. In BEAS-2B cells, occludin overexpression suppressed LPS-induced IL-8 release, restored barrier integrity, and reduced F-actin remodeling, whereas C-terminal deletion abolished these effects. The C-terminal occludin peptide (391∼412) significantly decreased IL-8 production, improved barrier function, and suppressed cytoskeletal changes, while a mutant peptide was ineffective. Transcriptomic analyses identified occludin as a central suppressor of inflammatory signaling. Mechanistically, the peptide inhibited p38 activation, preserved mitochondrial structure, and reduced mtROS production. In vivo, peptide pretreatment improved survival, lowered IL-1β, IL-6, IL-8, and TNF-α levels, and reduced goblet cell hyperplasia and inflammatory infiltration. Immune profiling further revealed restored T-cell populations, reduced myeloid expansion, and enhanced M2 alveolar macrophage polarization. The occludin C-terminal–derived peptide exerts robust anti-inflammatory, barrier-protective effects, and a modulator of mitochondrial redox balance representing a promising therapeutic candidate for LPS-induced and potentially broader inflammatory lung diseases.
Background Macrophage polarization plays a crucial role in the immune response, and gangliosides regulate macrophage function. In this study, we investigated the role of gangliosides in modulating macrophage morphology and function in response to M2 polarization induced by interleukin (IL)-4 and IL-13. Methods The mouse monocyte/macrophage cell line RAW264.7 and bone marrow macrophages were used to assess the role of gangliosides in macrophages. Additionally, St3gal5 knockdown was achieved using small interfering RNA constructs for further examinations. Results Elongation of M2-polarized macrophages in the presence of IL-4 and IL-13 was associated with increased ganglioside synthesis, as shown by reverse transcription-polymerase chain reaction and immunoblot analyses. Pretreatment with D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol and St3gal5 knockdown significantly reduced elongation, indicating that gangliosides play a substantial role in this process. Flow cytometry revealed that ganglioside monosialodihexosylganglioside (GM3) and ganglioside disialodihexosylganglioside (GD3) expression was significantly upregulated in M2-polarized macrophages. Moreover, transwell migration assays demonstrated that GM3 promoted macrophage migration, and this effect was abrogated by St3gal5 knockdown. Despite increased elongation and migration, phagocytic activity was reduced in elongated macrophages, as measured by the phagocytosis index using latex beads, which was reversed upon St3gal5 knockdown. Additionally, GM3 treatment activated the protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) signaling pathways, as confirmed by immunoblot analysis, demonstrating their role in ganglioside-induced elongation. Conclusions Our findings highlight the crucial role of gangliosides in regulating the morphological plasticity of macrophages via AKT and ERK activation to promote elongation, which results in increased migration and reduced phagocytosis. This study provides insights into the mechanism by which gangliosides influence macrophage function and immune responses.
Taste buds, the neuroepithelial organs responsible for the detection of gustatory stimuli in the oral cavity, arise from stem/progenitor cells among nearby basal keratinocytes. Using genetic lineage tracing, Lgr5 and Lgr6 were suggested as the specific markers for the stem/progenitor cells of taste buds, but recent evidence implied that taste buds may arise even in the absence of these markers. Thus, we wanted to verify the genetic lineage tracing of lingual Lgr5- and Lgr6-expressing cells. Unexpectedly, we found that antibody staining revealed more diverse Lgr5-expressing cells inside and outside the taste buds of circumvallate papillae than was previously suggested. We also found that, while tamoxifen-induced genetic recombination occurred only in cells expressing the Lgr5 reporter GFP, we did not see any increase in the number of recombined daughter cells induced by consecutive injections of tamoxifen. Similarly, we found that cells expressing Lgr6, another stem/progenitor cell marker candidate and an analog of Lgr5, also do not generate recombined clones. In contrast, Lgr5-expressing cells in fungiform papillae can transform into Lgr5-negative progeny. Together, our data indicate that lingual Lgr5- and Lgr6-expressing cells exhibit diversity in their capacity to transform into Lgr5- and Lgr6-negative cells, depending on their location. Our results complement previous findings that did not distinguish this diversity.
The gram-negative bacterium lipopolysaccharide (LPS) is frequently administered to generate models of systemic inflammation. However, there are several side effects and no effective treatment for LPS-induced systemic inflammation. PEGylated PDZ peptide based on zonula occludens-1 (ZO-1) was analyzed for its effects on systemic inflammation induced by LPS. PDZ peptide administration led to the restoration of tissue injuries (kidney, liver, and lung) and prevented alterations in biochemical plasma markers. The production of pro-inflammatory cytokines was significantly decreased in the plasma and lung BALF in the PDZ-administered mice. Flow cytometry analysis revealed the PDZ peptide significantly inhibited inflammation, mainly by decreasing the population of M1 macrophages, and neutrophils (immature and mature), and increasing M2 macrophages. Using RNA sequencing analysis, the expression levels of the NF-κB-related proteins were lower in PDZ-treated cells than in LPS-treated cells. In addition, wild-type PDZ peptide significantly increased mitochondrial membrane integrity and decreased LPS-induced mitochondria fission. Interestingly, PDZ peptide dramatically could reduce LPS-induced NF-κB signaling, ROS production, and the expression of M1 macrophage marker proteins, but increased the expression of M2 macrophage marker proteins. These results indicated that PEGylated PDZ peptide inhibits LPS-induced systemic inflammation, reducing tissue injuries and reestablishing homeostasis, and may be a therapeutic candidate against systemic inflammation.
Skeletal muscle loss leads to decreased quality of life, increased incidence of chronic disease and mortality. To identify functional food materials to alleviate muscle atrophy, we built a multitarget-based machine learning system to identify novel phytochemicals that can inhibit TGF-ss, which induce muscle weakness, and increase PGC-1a, a target of exercise mimetics. The multitarget-based machine learning system is built as an ensemble model of four algorithms with each optimal input representation. Citrusinol was identified by our model, and its anti-atrophy effects were validated using C2C12 cells. Citrusinol enhanced protein synthesis via AKT/mTORC1 pathway, increased myogenic differentiation, and increased PGC-1a and its downstream regulators, MEF2A and TFAM. Citrusinol attenuated CT26-induced myotube atrophy by blocking TGF-ss, p-SMAD3, MAFbx, and TGF ss-induced MuRF1 and p-SMAD3. These results suggest that the proposed model can effectively identify functional foods to manage muscle atrophy; additionally, citrusinol was demonstrated as a promising candidate for future animal experiments.
Aging is a complex series of multi-organ processes that occur in various organisms. As such, an in vivo study using an animal model of aging is necessary to define its exact mechanisms and identify anti-aging substances. Using Drosophila as an in vivo model system, we identified Crataegus pinnatifida extract (CPE) as a novel anti-aging substance. Regardless of sex, Drosophila treated with CPE showed a significantly increased lifespan compared to those without CPE. In this study, we also evaluated the involvement of CPE in aging-related biochemical pathways, including TOR, stem cell generation, and antioxidative effects, and found that the representative genes of each pathway were induced by CPE administration. CPE administration did not result in significant differences in fecundity, locomotion, feeding amount, or TAG level. These conclusions suggest that CPE is a good candidate as an anti-aging food substance capable of promoting a healthy lifespan.
Endometriosis is a gynecological disease prevalent in women of reproductive age, and it is characterized by the ectopic presence and growth of the eutopic endometrium. The pathophysiology and diagnostic biomarkers of endometriosis have not yet been comprehensively determined. To discover molecular markers and pathways underlying the pathogenesis of endometriosis, we identified differentially expressed genes (DEGs) in three Gene Expression Omnibus microarray datasets (GSE11691, GSE23339, and GSE7305) and performed gene set enrichment analysis (GSEA) and protein–protein interaction (PPI) network analyses. We also validated the identified genes via immunohistochemical analysis of tissues obtained from patients with endometriosis or healthy volunteers. A total of 118 DEGs (79 upregulated and 39 downregulated) were detected in each dataset with a lower (fold change) FC cutoff (log2|FC| > 1), and 17 DEGs (11 upregulated and six downregulated) with a higher FC cutoff (log2|FC| > 2). KEGG and GO functional analyses revealed enrichment of signaling pathways associated with inflammation, complement activation, cell adhesion, and extracellular matrix in endometriotic tissues. Upregulation of seven genes (C7, CFH, FZD7, LY96, PDLIM3, PTGIS, and WISP2) out of 17 was validated via comparison with external gene sets, and protein expression of four genes (LY96, PDLIM3, PTGIS, and WISP2) was further analyzed by immunohistochemistry and western blot analysis. Based on these results, we suggest that TLR4/NF-κB and Wnt/frizzled signaling pathways, as well as estrogen receptors, regulate the progression of endometriosis. These pathways may be therapeutic and diagnostic targets for endometriosis.
Research using experimental animals has substantially contributed to advances in science and medicine. Animal experiments are nearly essential for biomedical research and development efforts. Because many animals are sacrificed, researchers should consider the welfare of experimental animals and related ethical issues, along with the successful results of their experiments. This review introduces the criteria that should be considered in terms of experimental animal ethics, based on the principles of the 3 R’s: replacement, representing careful consideration of the need for animal experiments; reduction, representing the use of the minimal number of animals to obtain meaningful experimental results; and refinement, representing continuous effects to find alternative methods to reduce pain and distress in experimental animals. Based on these principles, the following points should be considered when planning experiments: the necessity of animal experiments; alternatives to animal experiments; the relevance of the species and numbers of experimental animals; appropriate assessment and management of pain; the proper usage of sedatives, painkillers, and anesthesia; and valid timing for humane endpoints and euthanasia. These criteria are beneficial for both experimental animals and researchers because careful handling to ensure experimental animal welfare guarantees that scientific research will yield convincing, repeatable, and accurate results.
Olfactory receptors (ORs) account for 49% of all G protein-coupled receptors (GPCRs), which are important targets for drug discovery, and hence ORs may also be potential drug targets. Various ORs are expressed in breast cancer cells; however, most of them are orphan receptors, and thus, their functions are unknown. Herein, we present an experimental strategy using a surface plasmon resonance (SPR) system and a cell-based assay that allowed the identification of orphan OR6M1 as a new anticancer target in the MCF-7 breast cancer cell line. After the construction of stable OR6M1-expressing cells, the SPR-based screening of 108 chemicals for ligand activity was performed against OR6M1-expressing whole cells (primary screening) or membrane fragments (secondary screening). As a result, anthraquinone (AQ) and rutin were discovered to be new OR6M1 ligands. Based on calcium imaging in OR6M1-expressing Hana3A cells, AQ and rutin were classified as an OR6M1 agonist and antagonist, respectively. Cell viability and live/dead assays showed that AQ induced the death of MCF-7 cells, which was inhibited by rutin. Therefore, OR6M1 may be considered an anticancer target, and AQ may be considered a chemotherapeutic agent. This combined method can be widely used to discover the ligands and functions of other orphan GPCRs.
Soy isoflavones are popular ingredients with anti-adipogenic and anti-lipogenic properties. The anti-adipogenic and anti-lipogenic properties of genistein are well-known, but those of genistin and glycitein remain unknown, and those of daidzein are characterized by contrasting data. Therefore, the purpose of our study was to investigate the effects of daidzein, glycitein, genistein, and genistin on adipogenesis and lipogenesis in 3T3-L1 cells. Proliferation of 3T3-L1 preadipocytes was unaffected by genistin and glycitein, but it was affected by 50 and 100 µM genistein and 100 µM daidzein for 48 h. Among the four isoflavones, only 50 and 100 µM genistin and genistein markedly suppressed lipid accumulation during adipogenesis in 3T3-L1 cells through a similar signaling pathway in a dose-dependent manner. Genistin and genistein suppress adipocyte-specific proteins and genes, such as peroxisome proliferator-activated receptor γ (PPARγ), CCAAT-enhancer-binding protein α (C/EBPα), and adipocyte binding protein 2 (aP2)/fatty acid-binding protein 4 (FABP4), and lipogenic enzymes such as ATP citrate lyase (ACL), acetyl-CoA carboxylase 1 (ACC1), and fatty acid synthase (FAS). Both isoflavones also activate AMP-activated protein kinase α (AMPKα), an essential factor in adipocyte differentiation, and inhibited sterol regulatory element-binding transcription factor 1c (SREBP-1c). These results indicate that genistin is a potent anti-adipogenic and anti-lipogenic agent.
Age-related macular degeneration (AMD) is a major cause of irreversible loss of vision with 80–90% of patients demonstrating dry type AMD. Dry AMD could possibly be prevented by polyphenol-rich medicinal foods by the inhibition of N-retinylidene-N-retinylethanolamine (A2E)-induced oxidative stress and cell damage. Arctium lappa L. (AL) leaves are medicinal and have antioxidant activity. The purpose of this study was to elucidate the protective effects of the extract of AL leaves (ALE) on dry AMD models, including in vitro A2E-induced damage in ARPE-19 cells, a human retinal pigment epithelial cell line, and in vivo light-induced retinal damage in BALB/c mice. According to the total phenolic contents (TPCs), total flavonoid contents (TFCs) and antioxidant activities, ALE was rich in polyphenols and had antioxidant efficacies on 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and 2′,7′-dichlorofluorescin diacetate (DCFDA) assays. The effects of ALE on A2E accumulation and A2E-induced cell death were also monitored. Despite continued exposure to A2E (10 μM), ALE attenuated A2E accumulation in APRE-19 cells with levels similar to lutein. A2E-induced cell death at high concentration (25 μM) was also suppressed by ALE by inhibiting the apoptotic signaling pathway. Furthermore, ALE could protect the outer nuclear layer (ONL) in the retina from light-induced AMD in BALB/c mice. In conclusion, ALE could be considered a potentially valuable medicinal food for dry AMD.
:Background: The fruits of Momordica charantia, commonly known as bitter melon, have been used as a traditional medicine in several countries. Some studies have reported its pharmacological effects in various disorders. Objectives: Because there have been little reports on charantin's role as an analgesic, we evaluated its pain relief effect to determine if it could be a novel pain killer candidate. Materials and Methods: We established post-operative and neuropathic pain models, which represent acute and chronic pain, respectively. Mechanical withdrawal threshold assay and ultrasonic vocalization analysis were used as behavioral tests. Results: The administration of charantin reduced both the post-operative and neuropathic pain. The application of charantin did not make a difference in the activation of action potentials of dorsal root ganglion (DRG) neurons. However, charantin inhibited the induction of the pro-inflammatory cytokines interleukin IL-12 and IL-1β in DRG neurons. Conclusion: Our findings indicate that charantin seems to relieve pain by inhibiting the inflammatory process rather than by directly influencing the activity of neurons. We conclude that charantin, the commercially available extract from M. charantia, has great efficacy as a novel analgesic compound.
Cnidium officinale, widely cultivated in East Asia, has been reported to exhibit pharmacological efficacy in various disorders. However, little has been reported on its role as a pain killer. In this study, we reveal that the C. officinale extract (COE) has great efficacy as a novel analgesic in various in vivo pain models. Administration of COE attenuated hypersensitivity in all postoperative, neuropathic, and menopausal pain models. Decreased hyperalgesia was confirmed by a mechanical withdrawal threshold assay and ultrasonic vocalization call analysis. In addition, application of COE inhibited the induction of the proinflammatory cytokines and calpain-3 on dorsal root ganglion neurons in a spared nerve injury rat model. Treatment with ferulic acid, which was identified as one of the components of COE by HPLC analysis, alleviated nociceptive behaviors. Our findings suggest that ferulic acid is an active compound from COE, and COE is a potential phytomedical source for pain relief by inhibiting the process of inflammation.
Gramine is an alkaloid found in giant reed and maple. Many reports discuss the health-beneficial effects of gramine in inflammation, angiogenesis, and cell growth. However, the physiological role of gramine in the odorant-induced signal transduction pathway has not yet been investigated. Therefore, in this study, we aimed to evaluate the effects of gramine on odorant-stimulated non-neuronal 3T3-L1 cells endogenously expressing the murine eugenol receptor, olfr73. We showed that gramine inhibited the eugenol-induced calcium influx and cyclic AMP (cAMP) elevation in the 3T3-L1 cells without any toxicity. In addition, gramine decreased the phosphorylation of protein kinase A and cAMP response element binding protein (CREB), which are known as downstream targets of cAMP, in eugenolstimulated 3T3-L1 cells. These results indicate that gramine suppresses the eugenol-induced signal transduction pathway in non-neuronal 3T3-L1 cells by modulating calcium influx, cAMP levels, and CREB phosphorylation.
This study was performed to assess the effect of plasma-discharged water recycling technology as irrigation water on soybean sprout production. Two different types of irrigation water were used individually for cultivation, including plasma discharged water as a source of oxides of nitrogen and tap water, irrigation water was recycled for every 30 minutes. Plasma discharged irrigation water reduced overall 4.3 log CFU/ml aerobic microbe and 7.0 log CFU/ml of artificially inoculated S. Typhimurium within 5 minutes and 2 minutes, respectively, therefore sprout production occurs in a hygienic environment. Using of plasma-discharged water for cultivation, increases the amount of ascorbate, asparagine, and γ-aminobutyric acid (GABA) significantly (p < 0.05), in the part of cotyledon and hypocotyl of soybean sprout during 1 to 4 days of farming. A NO scavenger, 2-(4-carboxy-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxy-3-oxide (cPTIO), was added in irrigation water to elucidate the roles of the oxides of nitrogen such as NO3−, NO2− generated in plasma discharged water. It was observed that all three nutrients decreased in the cotyledon part, whereas ascorbate and GABA contents increased in the hypocotyl and radicle part of bean sprout for the same duration of farming. The addition of NO scavenger in the irrigation water also reduced growth and overall yield of the soybean sprouts. A recycling water system with plasma-discharged water helped to reduce the amount of water consumption and allowed soybean sprouts growth in a hygienic environment during the hydroponic production.
Animals discriminate nutritious food from toxic substances using their sense of taste. Since taste perception requires taste receptor cells to come into contact with water-soluble chemicals, it is a form of contact chemosensation. Concurrent with that contact, mechanosensitive cells detect the texture of food and also contribute to the regulation of feeding. Little is known, however, about the extent to which chemosensitive and mechanosensitive circuits interact. Here, we show Drosophila prefers soft food at the expense of sweetness and that this preference requires labellar mechanosensory neurons (MNs) and the mechanosensory channel Nanchung. Activation of these labellar MNs causes GABAergic inhibition of sweet-sensing gustatory receptor neurons, reducing the perceived intensity of a sweet stimulus. These findings expand our understanding of the ways different sensory modalities cooperate to shape animal behaviour.
Although the five basic taste qualities-sweet, sour, bitter, salty and umami-can be recognized by the respective gustatory system, interactions between these taste qualities are often experienced when food is consumed. Specifically, the umami taste has been investigated in terms of whether it enhances or reduces the other taste modalities. These studies, however, are based on individual perception and not on a molecular level. In this study we investigated umami-sweet taste interactions using umami compounds including monosodium glutamate (MSG), 5'-mononucleotides and glutamyl-dipeptides, glutamate-glutamate (Glu-Glu) and glutamate-aspartic acid (Glu-Asp), in human sweet taste receptor hT1R2/hT1R3-expressing cells. The sensitivity of sucrose to hT1R2/hT1R3 was significantly attenuated by MSG and umami active peptides but not by umami active nucleotides. Inhibition of sweet receptor activation by MSG and glutamyl peptides is obvious when sweet receptors are activated by sweeteners that target the extracellular domain (ECD) of T1R2, such as sucrose and acesulfame K, but not by cyclamate, which interact with the T1R3 transmembrane domain (TMD). Application of umami compounds with lactisole, inhibitory drugs that target T1R3, exerted a more severe inhibitory effect. The inhibition was also observed with F778A sweet receptor mutant, which have the defect in function of T1R3 TMD. These results suggest that umami peptides affect sweet taste receptors and this interaction prevents sweet receptor agonists from binding to the T1R2 ECD in an allosteric manner, not to the T1R3. This is the first report to define the interaction between umami and sweet taste receptors.