Quercitrin ameliorates the development of systemic lupus erythematosus-like disease in a chronic graft-versus-host murine model

T cell dysregulation in rheumatoid arthritis: Recent advances and natural product interventions

Autoimmune diseases result from chronic and dysregulated activation of the immune system, culminating in pathological self-tissue damage. These disorders are primarily driven by adaptive immune responses, particularly those mediated by T and B lymphocytes, which mistakenly target self-antigens expressed in host tissues. In rheumatoid arthritis (RA), the pathogenesis is closely associated with the emergence of tissue-invasive effector T cells and the functional impairment of regulatory T cells (Tregs), both of which play pivotal roles in disease progression. Therapeutic interventions targeting these dysregulated T cell populations have emerged as a promising strategy for RA management. Although synthetic immunosuppressants remain the mainstay of RA treatment, their long-term application is often hampered by adverse effects, diminished therapeutic efficacy, and poor patient adherence. These limitations highlight the critical need for the development of novel therapeutic approaches. Natural compounds derived from medicinal plants have been widely utilized in the clinical management of RA, with growing evidence supporting their immunomodulatory potential, particularly in restoring T cell-mediated immune tolerance. This review aims to provide a comprehensive overview of recent advances in understanding T cell dysregulation in RA and to elucidate the mechanisms through which natural compounds regulate immune responses. By integrating current findings, this work seeks to offer a theoretical foundation for the optimized use of natural compounds in the treatment of RA, while exploring their potential in advancing precision medicine and personalized therapeutic strategies.

Development, optimization and comparison of solid-liquid and liquid-liquid microextraction for the determination of four flavonols in Schinus molle L. using high-performance liquid chromatography coupled with second-order data modeling

Flavonoids are particularly interesting because they have a broad spectrum of biological effects, including antioxidant and free radical scavenging activities. In this work, solid-liquid microextraction and dispersive liquid-liquid microextraction enhanced by ultrasound were developed and compared with the conventional method (Soxhlet extraction) to optimize the extraction of four flavonoids: rutin, quercitrin, quercetin, and myricetin in samples of Schinus molle (Aguaribay). During the development of the analytical method, different chemometric tools were used to optimize the microextraction procedure. In addition, an analytical method based on high-performance liquid chromatography with diode array detector (HPLC-DAD) and second order calibration using multivariate curve resolution-alternating least square (MCR-ALS) is presented to quantify the flavonoids with limits of quantification between 0.011 and 0.082 µg mL-1. Finally, solid-liquid microextraction using 4.00 mL water/ethanol (54.3:45.7%), 14 s vortex, and 45 min was selected as the most suitable method due to its high recovery rate and environmental friendliness (with a greenness score of 0.78). After the optimization step, the concentrations found in the plant samples were 1825.3, 632.6, 110.2, and 18.9 µg g-1 for rutin, quercitrin, quercetin, and myricetin, respectively. The present work is the first achievement of simultaneously determining these four analytes with exceptional sensitivity, demonstrating lower LOQs compared to previous reports.

Pharmacological Mechanism of Chinese Medicine in Systemic Lupus Erythematosus: A Narrative Review

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder affecting multiple systems, characterized by the development of harmful autoantibodies and immune complexes that lead to damage in organs and tissues. Chinese medicine (CM) plays a role in mitigating complications, enhancing treatment effectiveness, and reducing toxicity of concurrent medications, and ensuring a safe pregnancy. However, CM mainly solves the disease comprehensively through multi-target and multi-channel regulation process, therefore, its treatment mechanism is often complicated, involving many molecular links. This review introduces the research progress of pathogenesis of SLE from the aspects of genetics, epigenetics, innate immunity and acquired immunity, and then discusses the molecular mechanism and target of single Chinese herbal medicine and prescription that are commonly used and effective in clinic to treat SLE.

Metabolism of quercitrin in the colon and its beneficial regulatory effects on gut microbiota

BACKGROUND

Quercitrin is a dietary flavonoid widely found in plants with various physiological activities. However, whether quercitrin alters gut microbiota in vivo is not well understood. The aim of this study was to investigate metabolism of quercitrin in the colon and its regulation on gut microbiota in mice.

RESULTS

Herein, 22 flavonoids related to quercitrin metabolism were identified based on ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). Gas chromatography and 16S rDNA gene sequencing were used to investigate short-chain fatty acid (SCFA) content and diversity of composition of gut microbiota, respectively. The results showed that quercitrin significantly alters the beta-diversity of the gut microbiota, probiotics such as Akkermansia and Lactococcus were significantly increased, and the production of propanoate, isovalerate and hexanoate of the quercitrin group were enhanced significantly. The Spearman's association analysis provided evidence that Gardnerella and Akkermansia have obvious correlations with most of quercitrin metabolites and SCFAs.

CONCLUSION

Quercitrin and its metabolites in the colon altered the structure of the mice gut microbiota and increased the content of SCFAs. Our experiments provide valuable insights into quercitrin research and application. © 2024 Society of Chemical Industry.

Roles of macrophages in lupus nephritis

LN is a serious complication of systemic lupus erythematosus (SLE), affecting up to 60% of patients with SLE and may lead to end-stage renal disease (ESRD). Macrophages play multifaceted roles in the pathogenesis of LN, including clearance of immune complexes, antigen presentation, regulation of inflammation, and tissue repair. Macrophages are abundant in the glomeruli and tubulointerstitium of LN patients and are positively correlated with serum creatinine levels and the severity of renal pathology. It has been shown that the infiltration of macrophages is closely associated with several clinical indicators, such as serum creatinine and complement C3 levels, anti-dsDNA antibody titers, Austin score, interstitial fibrosis and renal tubular atrophy. Moreover, cytokines expressed by macrophages were upregulated at LN onset and downregulated after remission, suggesting that macrophages may serve as markers of LN pathogenesis and remission. Therapies targeting macrophages have been shown to alleviate LN. There are two main types of macrophages in the kidney: kidney-resident macrophages (KRMs) and monocyte-derived macrophages (MDMs). KRMs and MDMs play different pathological roles in LN, with KRMs promoting leukocyte recruitment at sites of inflammation by expressing monocyte chemokines, while MDMs may exacerbate autoimmune responses by presenting immune complex antigens. Macrophages exhibit high plasticity and can differentiate into various phenotypes in response to distinct environmental stimuli. M1 (proinflammatory) macrophages are linked to the progression of active SLE, whereas the M2 (anti-inflammatory) phenotype is observed during the remission phase of LN. The polarization of macrophages in LN can be manipulated through multiple pathways, such as the modulation of signaling cascades including TLR 2/1, S1P, ERS, metabolic reprogramming, and HMGB1. This paper provides a comprehensive overview of the role of macrophages in the progression of lupus nephritis (LN), and elucidates how these cells and their secretory products function as indicators and therapeutic targets for the disease in the context of diagnosis and treatment of LN.

The Multifaceted Aspects of Oxidative Stress in the Skin and Other Tissues

Different tissues experience various levels of oxidative stress based on their function and protection from outside environments [...].

Gasdermin D deficiency aborts myeloid calcium influx to drive granulopoiesis in lupus nephritis

Gasdermin D (GSDMD) is emerging as an important player in autoimmune diseases, but its exact role in lupus nephritis (LN) remains controversial. Here, we identified markedly elevated GSDMD in human and mouse LN kidneys, predominantly in CD11b+ myeloid cells. Global or myeloid-conditional deletion of GSDMD was shown to exacerbate systemic autoimmunity and renal injury in lupus mice with both chronic graft-versus-host (cGVH) disease and nephrotoxic serum (NTS) nephritis. Interestingly, RNA sequencing and flow cytometry revealed that myeloid GSDMD deficiency enhanced granulopoiesis at the hematopoietic sites in LN mice, exhibiting remarkable enrichment of neutrophil-related genes, significant increases in total and immature neutrophils as well as granulocyte/macrophage progenitors (GMPs). GSDMD-deficient GMPs and all-trans-retinoic acid (ATRA)-stimulated human promyelocytes NB4 were further demonstrated to possess enhanced clonogenic and differentiation abilities compared with controls. Mechanistically, GSDMD knockdown promoted self-renewal and granulocyte differentiation by restricting calcium influx, contributing to granulopoiesis. Functionally, GSDMD deficiency led to increased pathogenic neutrophil extracellular traps (NETs) in lupus peripheral blood and bone marrow-derived neutrophils. Taken together, our data establish that GSDMD deletion accelerates LN development by promoting granulopoiesis in a calcium influx-regulated manner, unraveling its unrecognized critical role in LN pathogenesis.

Quercitrin improves cardiac remodeling following myocardial infarction by regulating macrophage polarization and metabolic reprogramming

The death and disability caused by myocardial infarction is a health problem that needs to be addressed worldwide, and poor cardiac repair and fibrosis after myocardial infarction seriously affect patient recovery. Postmyocardial infarction repair by M2 macrophages is of great significance for ventricular remodeling. Quercitrin (Que) is a common flavonoid in fruits and vegetables that has antioxidant, anti-inflammatory, antitumor and other effects, but whether it has a role in the treatment of myocardial infarction is unclear. In this study, we constructed a mouse myocardial infarction model and administered Que. We found through cardiac ultrasound that Que administration improved cardiac ejection fraction and reduced ventricular remodeling. Staining of heart sections and detection of fibrosis marker protein levels revealed that Que administration slowed fibrosis after myocardial infarction. Flow cytometry showed that the proportion of M2 macrophages in the mouse heart was increased and that the expression levels of M2 macrophage markers were increased in the Que-treated group. Finally, we identified by metabolomics that Que reduces glycolysis, increases aerobic phosphorylation, and alters arginine metabolic pathways, polarizing macrophages toward the M2 phenotype. Our research lays the foundation for the future application of Que in myocardial infarction and other cardiovascular diseases.

Restoration of aberrant gene expression of monocytes in systemic lupus erythematosus via a combined transcriptome-reversal and network-based drug repurposing strategy

BACKGROUND

Monocytes -key regulators of the innate immune response- are actively involved in the pathogenesis of systemic lupus erythematosus (SLE). We sought to identify novel compounds that might serve as monocyte-directed targeted therapies in SLE.

RESULTS

We performed mRNA sequencing in monocytes from 15 patients with active SLE and 10 healthy individuals. Disease activity was assessed with the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2 K). Leveraging the drug repurposing platforms iLINCS, CLUE and L1000CDS², we identified perturbagens capable of reversing the SLE monocyte signature. We identified transcription factors and microRNAs (miRNAs) that regulate the transcriptome of SLE monocytes, using the TRRUST and miRWalk databases, respectively. A gene regulatory network, integrating implicated transcription factors and miRNAs was constructed, and drugs targeting central components of the network were retrieved from the DGIDb database. Inhibitors of the NF-κB pathway, compounds targeting the heat shock protein 90 (HSP90), as well as a small molecule disrupting the Pim-1/NFATc1/NLRP3 signaling axis were predicted to efficiently counteract the aberrant monocyte gene signature in SLE. An additional analysis was conducted, to enhance the specificity of our drug repurposing approach on monocytes, using the iLINCS, CLUE and L1000CDS² platforms on publicly available datasets from circulating B-lymphocytes, CD4⁺ and CD8⁺ T-cells, derived from SLE patients. Through this approach we identified, small molecule compounds, that could potentially affect more selectively the transcriptome of SLE monocytes, such as, certain NF-κB pathway inhibitors, Pim-1 and SYK kinase inhibitors. Furthermore, according to our network-based drug repurposing approach, an IL-12/23 inhibitor and an EGFR inhibitor may represent potential drug candidates in SLE.

CONCLUSIONS

Application of two independent - a transcriptome-reversal and a network-based -drug repurposing strategies uncovered novel agents that might remedy transcriptional disturbances of monocytes in SLE.

Integrated LC-MS/MS and network pharmacology approach for predictingactive ingredients and pharmacological mechanisms of Tribulus terrestris L. against cardiac diseases

Tribulus terrestris L. (Gokshura) is a medicinal herb used for treating cardiac diseases and several other diseases. However, the active ingredients and the possible mechanism of action for treating cardiac diseases remain unclear. Hence, the study was designed to identify the active ingredients and to explore the potential mechanism of action of Tribulus terrestris L. for treating cardiac diseases by an integrated approach of metabolomics and network pharmacology. We performed HPLC-QTOF-MS/MS analysis to identify putative compounds and network pharmacology approach for predictive key targets and pathways. Using molecular docking and molecular dynamics simulation, we identified the active ingredients in Tribulus terrestris L. that can act as putative lead compounds to treat cardiac diseases. A total of 55 putative compounds were identified using methanolic extract of Tribulus terrestris L. using HPLC-QTOF-MS/MS analysis. Network pharmacology analysis predicted 32 human protein targets from 25 secondary metabolites, which have shown direct interaction with cardiac diseases. Based on the degrees of interaction, the hub targets such as TACR1, F2, F2R, ADRA1B, CHRM5, ADRA1A, ADRA1D, HTR2B, and AVPR1A were identified. In silico molecular docking and simulation resulted in the identification of active ingredients such as Kaempferol 3-rutinoside 7-glucuronide, Keioside, rutin, moupinamide, aurantiamide, quercetin-3-o-α-rhamnoside, tribuloside, and 3'',6''- Di-O-p-coumaroyltrifolin against hub protein targets. Hence, these compounds could be potential lead compounds for treating cardiac diseases. A further assessment of its efficacy can be made based on in vivo and in vitro studies for better understanding and strong assertion.Communicated by Ramaswamy H. Sarma.

Potential Targets and Mechanisms of Jiedu Quyu Ziyin Decoction for Treating SLE-GIOP: Based on Network Pharmacology and Molecular Docking

Background

Systemic lupus erythematosus (SLE) is characterized by poor regulation of the immune response leading to chronic inflammation and multiple organ dysfunction. Glucocorticoid (GC) is currently one of the main treatments. However, a high dose or prolonged use of GC may result in glucocorticoid-induced osteoporosis (GIOP). Jiedu Quyu Ziyin decoction (JP) is effective in treating SLE and previous clinical studies have proved that JP can prevent and treat SLE steroid osteoporosis (SLE-GIOP). We aim to examine JPs main mechanism on SLE-GIOP through network pharmacology and molecular docking.

Methods

TCMSP and TCMID databases were used to screen potential active compounds and targets of JP. The SLE-GIOP targets are collected from GeneCards, OMIM, PharmGkb, TTD, and DrugBank databases. R software was used to obtain the cross-targets of JP and SLE-GIOP and to perform GO and KEGG enrichment analysis. Cytoscape software was used to make the Chinese Medicines-Active Ingredient-Intersection Targets network diagram. STRING database construct protein-protein interaction network and obtain the core targets. Auto Dock Tools and Pymol software were used for docking.

Results

Fifty eight targets overlapped between JP and SLE-GIOP were suggested as potential targets of JP in the treatment of SLE-GIOP. Network topology analysis identified five core targets. GO enrichment analysis was obtained 1,968 items, and the top 10 biological process, closeness centrality, and molecular function were displayed. A total of 154 signaling pathways were obtained by KEGG enrichment analysis, and the top 30 signaling pathways were displayed. JP was well bound by MAPK1, TP53, and MYC according to the molecular docking results.

Conclusion

We investigated the potential targets and signaling pathways of JP against SLE-GIOP in this study. It shows that JP is most likely to achieve the purpose of treating SLE-GIOP by promoting the proliferation and differentiation of osteoblasts. A solid theoretical foundation will be provided for the future study of clinical and experimental topics.

Lupus Recipe inhibits cGVHD-induced lupus nephritis in mice and promote renal LC3-associated autophagy

Lupus nephritis (LN) is one of the most severe manifestations of systemic lupus erythematosus (SLE). The chronic graft versus host disease (cGVHD) mouse model is a well-established model of SLE. LC3-associated autophagy plays a critical role in extracellular particle clearance, including pathogens and apoptotic cells. Lupus Recipe (LR) is a Chinese herbal compound that has been proven to be effective in treating SLE. In the study, we investigated the protective effects of LR or LR combined with prednisone on cGVHD mouse model and LC3-associated autophagy in the kidney. The mice were subjected to six groups. The LR treatment group received LR at the dosage of 1.15 and 2.3 g/kg/day, respectively. The corticosteroid treatment group received prednisone at a dosage of 5 mg/kg/day. The combination treatment group received LR at a dosage of 2.3 g/kg/day, and prednisone at 2.5 mg/kg/day. LR treatment reduced proteinuria and serum triglyceride levels, as well as spleen weight. LR also alleviated pathologic damage and immunoglobulin G deposition in the kidney. LR combined with a low dose of prednisone significantly improved kidney function and decreased serum triglyceride, total cholesterol, and spleen weight. In addition, combination treatment relieved kidney injury more effectively than LR alone. Western blot revealed that LR treatment or LR combined with prednisone increased the LC3-associated autophagy protein of Rubicon and Nox2, as well as LC3I levels in the kidney tissues. In conclusion, LR inhibited the manifestation of cGVHD-induced LN, which may attribute to the increased levels of LC3-associated autophagy.

Flavonoids of Haloxylon salicornicum (Rimth) prevent cisplatin-induced acute kidney injury by modulating oxidative stress, inflammation, Nrf2, and SIRT1

Cisplatin (CIS) is an effective chemotherapeutic drug used for the treatment of many types of cancers, but its use is associated with adverse effects. Nephrotoxicity is a serious side effect of CIS and limits its therapeutic utility. Haloxylon salicornicum is a desert shrub used traditionally in the treatment of inflammatory disorders, but neither its flavonoid content nor its protective efficacy against CIS nephrotoxicity has been investigated. In this study, seven flavonoids were isolated from H. salicornicum methanolic extract (HSE) and showed in silico binding affinity with NF-κB, Keap1, and SIRT1. The protective effect of HSE against CIS nephrotoxicity was investigated. Rats received HSE (100, 200, and 400 mg/kg) for 14 days followed by a single injection of CIS. The drug increased Kim-1, BUN, and creatinine and caused multiple histopathological changes. CIS-administered rats showed an increase in renal ROS, MDA, NO, TNF-α, IL-1β, and NF-κB p65. HSE prevented tissue injury, and diminished ROS, NF-κB, and inflammatory mediators. HSE enhanced antioxidants and Bcl-2 and downregulated pro-apoptosis markers. These effects were associated with downregulation of Keap1 and microRNA-34a, and upregulation of SIRT1 and Nrf2/HO-1 signaling. In conclusion, H. salicornicum is rich in flavonoids, and its extract prevented oxidative stress, inflammation, and kidney injury, and modulated Nrf2/HO-1 and SIRT1 signaling in CIS-treated rats.

Molecular mechanism of QH-BJ drug pair in the treatment of systemic lupus erythematosus based on network pharmacology and molecular docking

To analyze the molecular mechanism of Qinghao-Biejia (QH-BJ) drug pair in the treatment of systemic lupus erythematosus (SLE) based on the method of network pharmacology and molecular docking technology. The components and related targets of QH-BJ drug pair, as well as SLE-related targets, were obtained. Intersection targets of QH-BJ drug pair and SLE were screened to construct the protein-protein interaction network, conduct gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, and establish the component-target-pathway network. The core active components and core targets of QH-BJ drug pair for the treatment of SLE were selected, and molecular docking was carried out between the ligand components and the receptor target proteins. The core active components of QH-BJ drug pair for the treatment of SLE are luteolin, quercetin, and kaempferol; the core targets are PTGS2, HSP90AA1, RELA, MAPK1, MAPK14, AKT1, JUN, TNF, TP53. The ligand components can spontaneously bind to the receptor target proteins. Besides, QH-BJ drug pair is likely to act on PI3K/Akt signal pathway, interleukin-17 signal pathway, and TNF signal pathway in the treatment of SLE. The study indicates that QH-BJ drug pair might play a role in the treatment of SLE through multi-components, multi-targets, and multi-pathways.

The key player in the pathogenesis of environmental influence of systemic lupus erythematosus: Aryl hydrocarbon receptor

The aryl hydrocarbon receptor was previously known as an environmental receptor that modulates the cellular response to external environmental changes. In essence, the aryl hydrocarbon receptor is a cytoplasmic receptor and transcription factor that is activated by binding to the corresponding ligands, and they transmit relevant information by binding to DNA, thereby activating the transcription of various genes. Therefore, we can understand the development of certain diseases and discover new therapeutic targets by studying the regulation and function of AhR. Several autoimmune diseases, including systemic lupus erythematosus (SLE), have been connected to AhR in previous studies. SLE is a classic autoimmune disease characterized by multi-organ damage and disruption of immune tolerance. We discuss here the homeostatic regulation of AhR and its ligands among various types of immune cells, pathophysiological roles, in addition to the roles of various related cytokines and signaling pathways in the occurrence and development of SLE.

Drug Candidates for Autoimmune Diseases

Most of the immunosuppressive drugs used in the clinic to prevent organ rejection or to treat autoimmune disorders were originally isolated from fungi or bacteria. Therefore, in addition to plants, these are valuable sources for identification of new potent drugs. Many side effects of established drugs limit their usage and make the identification of new immunosuppressants necessary. In this review, we present a comprehensive overview of natural products with potent anti-inflammatory activities that have been tested successfully in different models of chronic inflammatory autoimmune diseases. Some of these candidates already have passed first clinical trials. The anti-inflammatory potency of these natural products was often comparable to those of established drugs, and they could be used at least in addition to standard therapy to reduce their dose to minimize unwanted side effects. A frequent mode of action is the inhibition of classical inflammatory signaling pathways, such as NF-κB, in combination with downregulation of oxidative stress. A drawback for the therapeutic use of those natural products is their moderate bioavailability, which can be optimized by chemical modifications and, in addition, further safety studies are necessary. Altogether, very interesting candidate compounds exist which have the potential to serve as starting points for the development of new immunosuppressive drugs.

Flavonoids in Treatment of Chronic Kidney Disease

Chronic kidney disease (CKD) is a progressive systemic disease, which changes the function and structure of the kidneys irreversibly over months or years. The final common pathological manifestation of chronic kidney disease is renal fibrosis and is characterized by glomerulosclerosis, tubular atrophy, and interstitial fibrosis. In recent years, numerous studies have reported the therapeutic benefits of natural products against modern diseases. Substantial attention has been focused on the biological role of polyphenols, in particular flavonoids, presenting broadly in plants and diets, referring to thousands of plant compounds with a common basic structure. Evidence-based pharmacological data have shown that flavonoids play an important role in preventing and managing CKD and renal fibrosis. These compounds can prevent renal dysfunction and improve renal function by blocking or suppressing deleterious pathways such as oxidative stress and inflammation. In this review, we summarize the function and beneficial properties of common flavonoids for the treatment of CKD and the relative risk factors of CKD.

Medicinal Plant Extracts and Natural Compounds for the Treatment of Cutaneous Lupus Erythematosus: A Systematic Review

Cutaneous lupus erythematosus (CLE) is a group of autoimmune connective tissue disorders that significantly impact quality of life. Current treatment approaches typically use antimalarial medications, though patients may become recalcitrant. Other treatment options include general immunosuppressants, highlighting the need for more and more targeted treatment options. The purpose of this systematic review was to identify potential compounds that could be repurposed for CLE from natural products since many rheumatologic drugs are derived from natural products, including antimalarials. This study was registered with PROSPERO, the international prospective register of systematic reviews (registration number CRD42021251048). We comprehensively searched Ovid Medline, Cochrane Library, and Scopus databases from inception to April 27th, 2021. These terms included cutaneous lupus erythematosus; general plant, fungus, bacteria terminology; selected plants and plant-derived products; selected antimalarials; and JAK inhibitors. Our search yielded 13,970 studies, of which 1,362 were duplicates. We screened 12,608 abstracts, found 12,043 to be irrelevant, and assessed 565 full-text studies for eligibility. Of these, 506 were excluded, and 59 studies were included in the data extraction. The ROBINS-I risk of bias assessment tool was used to assess studies that met our inclusion criteria. According to our findings, several natural compounds do reduce inflammation in lupus and other autoimmune skin diseases in studies using in vitro methods, mouse models, and clinical observational studies, along with a few randomized clinical trials. Our study has cataloged evidence in support of potential natural compounds and plant extracts that could serve as novel sources of active ingredients for the treatment of CLE. It is imperative that further studies in mice and humans are conducted to validate these findings.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=251048.

Chemistry, pharmacokinetics, pharmacological activities, and toxicity of Quercitrin

Quercitrin is a naturally available type of flavonoid that commonly functions as the dietary ingredient and supplement. So far, a wide spectrum of bioactivities of quercitrin have been revealed, including antioxidative stress, antiinflammation, anti-microorganisms, immunomodulation, analgesia, wound healing, and vasodilation. Based on these various pharmacological activities, increasing studies have focused on the potency of quercitrin in diverse diseases in recent years, such as bone metabolic diseases, gastrointestinal diseases, cardiovascular and cerebrovascular diseases, and others. In this paper, by collecting and summarizing publications from the recent years, the natural sources, pharmacological activities and roles in various diseases, pharmacokinetics, structure-activity relationship, as well as the toxicity of quercitrin were systematically reviewed. In addition, the underlying molecular mechanisms of quercitrin in treating related diseases, the dose-effect relationships, and the novel preparations were discussed on the purpose of broadening the application prospect of quercitrin as functional food and providing reference for its clinical application. Notably, clinical studies of quercitrin are insufficient at present, further high-quality studies are needed to firmly establish the clinical efficacy of quercitrin.

Quercitrin protects human bronchial epithelial cells from oxidative damage

Chronic obstructive pulmonary disease (COPD) is mainly caused by cigarette smoking (CS), with oxidative stress being one key component during its pathogenesis. This study aimed to investigate the effects of quercitrin (QE) on cigarette smoke extract (CSE)-induced cell apoptosis and oxidative stress in human bronchial epithelial cells (HBECs) and its underlying mechanism. HBECs were treated with 2% CSE for 24 h to establish in vitro COPD cellular models. CCK-8 assay and flow cytometry analysis were performed to evaluate cell viability and apoptosis, respectively. Western blotting was applied to examine protein levels and ELISA kits were used to examine contents of the indicated oxidant/antioxidant markers. The results demonstrated that CSE promoted apoptosis and suppressed viability of HBECs and QE reversed these effects. CSE caused increase in T-AOC, superoxide dismutase, and glutathione (GSH) peroxidase contents and decrease in MDA, reactive oxygen species , and GSH contents in HBECs, which were rescued by QE treatment. The CSE-induced Nrf2 nuclear translocation and elevation of NAD(P)H: quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1) expression were also reversed by QE in HBECs. The mitogen-activated protein kinase (MAPK) signaling was activated by CSE and further suppressed by QE in HBECs. Collectively, QE exerts a protective role in HBECs against cell apoptosis and oxidative damage via inactivation of the Nrf2/HO-1/NQO1 pathway and the MAPK/ERK pathway.

Investigating the Molecular Mechanism of Xijiao Dihuang Decoction for the Treatment of SLE Based on Network Pharmacology and Molecular Docking Analysis

Objective

To elucidate the main mechanism of Xijiao Dihuang decoction (XJDHT) for the treatment of systemic lupus erythematosus (SLE).

Methods

TCMSP, BATMAN-TCM, ETCM, and TCMID databases and literature search were used to screen the potential active compounds of XJDHT, and TCMSP and SwissProt databases were searched to predict the targets of the compounds. The targets of SLE were obtained from Genegards, OMIM, and DisGeNET databases, and Venn online platform was used to obtain the intersection targets of XJDHT and SLE. Afterwards, the PPI network was constructed by using the STRING database, and the core targets were identified by network topology analysis. GO and KEGG enrichment analyses were performed through R software, and molecular docking of the top three core targets and their corresponding compounds were accomplished by Autodock Vina and Pymol softwares.

Results

There were 30 potential active ingredients, 289 potential targets, and 129 intersection targets screened from the above databases. Network topology analysis identified 23 core targets, such as AKT1, TNF, IL6, IL1B, and INS. GO enrichment analysis obtained 2555 terms and mainly clustering on the react to lipopolysaccharide, membrane raft, and ubiquitin-like protein ligase binding. KEGG enrichment analysis obtained 187 signaling pathways, mainly concentrating on the lipid and atherosclerosis, AGE-RAGE signaling pathway in diabetic complications, fluid shear stress, and atherosclerosis. Molecular docking verified that the active compounds of XJDHT have the strong binding activity to the core targets.

Conclusion

This study preliminarily uncovers the mechanism of XJDHT acting on SLE through a “multicompound, multitarget, and multipathway” manner. XJDHT may achieve the treatment of SLE by inhibiting the proinflammatory factors, inflammatory signal cvtokines, proliferation, injury, and apoptosis processes. In summary, the present study would provide a promising theoretical basis for further clinical and experimental studies.

Diet and Hygiene in Modulating Autoimmunity During the Pandemic Era

The immune system is an efficiently toned machinery that discriminates between friends and foes for achieving both host defense and homeostasis. Deviation of immune recognition from foreign to self and/or long-lasting inflammatory responses results in the breakdown of tolerance. Meanwhile, educating the immune system and developing immunological memory are crucial for mounting defensive immune responses while protecting against autoimmunity. Still to elucidate is how diverse environmental factors could shape autoimmunity. The emergence of a world pandemic such as SARS-CoV-2 (COVID-19) not only threatens the more vulnerable individuals including those with autoimmune conditions but also promotes an unprecedented shift in people's dietary approaches while urging for extraordinary hygiene measures that likely contribute to the development or exacerbation of autoimmunity. Thus, there is an urgent need to understand how environmental factors modulate systemic autoimmunity to better mitigate the incidence and or severity of COVID-19 among the more vulnerable populations. Here, we discuss the effects of diet (macronutrients and micronutrients) and hygiene (the use of disinfectants) on autoimmunity with a focus on systemic lupus erythematosus.

Potential Implications of Quercetin in Autoimmune Diseases

Autoimmune diseases are a worldwide health problem with growing rates of morbidity, and are characterized by breakdown and dysregulation of the immune system. Although their etiology and pathogenesis remain unclear, the application of dietary supplements is gradually increasing in patients with autoimmune diseases, mainly due to their positive effects, relatively safety, and low cost. Quercetin is a natural flavonoid that is widely present in fruits, herbs, and vegetables. It has been shown to have a wide range of beneficial effects and biological activities, including anti-inflammation, anti-oxidation, and neuroprotection. In several recent studies quercetin has reportedly attenuated rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, and systemic lupus erythematosus in humans or animal models. This review summarizes the evidence for the pharmacological application of quercetin for autoimmune diseases, which supports the view that quercetin may be useful for their prevention and treatment.

Toxicity of Melastoma dodecandrum Lour. and its effects on lipopolysaccharide-induced inflammation and oxidative stress

Melastoma dodecandrum Lour. (MDL) is component used in traditional Chinese medicine that is widely distributed throughout southern China. MDL has been long utilized in clinical treatment for various conditions, such as inflammation. However, the toxicity and underlying anti-inflammatory mechanism of MDL remain to be elucidated. In the present study, Sprague-Dawley rats received intragastric administration of MDL for 2 months, and the toxicity of MDL was investigated. The rats were treated with lipopolysaccharide (LPS) for 8 h to determine the potential anti-inflammatory mechanism of MDL. The results demonstrated that MDL alone did not affect the expression levels of factors associated with inflammation (IL-1β, IL-6 and TNF-α) and oxidative stress [malondialdehyde (MDA), superoxide dismutase (SOD) and nitric oxide (NO)] in the rat serum and exerted no effects on rat liver and kidneys. By contrast, MDL attenuated LPS-induced inflammation and oxidative stress by regulating specific cytokines, such as IL-1β, IL-6, TNF-α, MDA, SOD and NO in the rat serum and alleviated LPS-induced liver and kidney damage. Additionally, compared with the LPS group, MDL inhibited CD4⁺ T cell differentiation into Th1 and Th17 cells and enhanced CD4⁺ T cell differentiation into Th2 and Treg cells. MDL also suppressed reactive oxygen species (ROS) production and mitochondrial apoptosis by modulating mitochondrial apoptosis-related proteins in spleen CD4⁺ T cells. In conclusion, the results of the present study demonstrated the non-toxic nature of MDL and revealed that it alleviated LPS-induced inflammation and oxidative stress by regulating differentiation and ROS production in CD4⁺ T cells.

Sulfation of Quercitrin, Epicatechin and Rutin by Human Cytosolic Sulfotransferases (SULTs): Differential Effects of SULT Genetic Polymorphisms

Radix Bupleuri is one of the most widely used herbal medicines in China for the treatment of fever, pain, and/or chronic inflammation. Quercitrin, epicatechin, and rutin, the flavonoids present in Radix Bupleuri, have been reported to display anti-inflammatory, antitumor, and antioxidant biological activities among others. Sulfation has been reported to play an important role in the metabolism of flavonoids. In this study, we aimed to systematically identify the human cytosolic sulfotransferase enzymes that are capable of catalyzing the sulfation of quercitrin, epicatechin, and rutin. Of the thirteen known human cytosolic sulfotransferases, three (cytosolic sulfotransferase 1A1, cytosolic sulfotransferase 1C2, and cytosolic sulfotransferase 1C4) displayed sulfating activity toward quercitrin, three (cytosolic sulfotransferase 1A1, cytosolic sulfotransferase 1A3, and cytosolic sulfotransferase 1C4) displayed sulfating activity toward epicatechin, and six (cytosolic sulfotransferase 1A1, cytosolic sulfotransferase 1A2, cytosolic sulfotransferase 1A3, cytosolic sulfotransferase 1B1, cytosolic sulfotransferase 1C4, and cytosolic sulfotransferase 1E1) displayed sulfating activity toward rutin. The kinetic parameters of the cytosolic sulfotransferases that showed the strongest sulfating activities were determined. To investigate the effects of genetic polymorphisms on the sulfation of quercitrin, epicatechin, and rutin, individual panels of cytosolic sulfotransferase allozymes previously prepared were analyzed and shown to display differential sulfating activities toward each of the three flavonoids. Taken together, these results provided a biochemical basis underlying the metabolism of quercitrin, epicatechin, and rutin through sulfation in humans.

Quercitrin Ameliorates Hyperlipidemia and Hepatic Steatosis in Ovariectomized Mice

Nonalcoholic fatty liver disease (NAFLD) is associated with progressive metabolic diseases. Estrogen deficiency increases the NAFLD risk among postmenopausal women. Thus, effective agents to prevent and treat NAFLD in postmenopausal women are required. Quercitrin (Quer) is a natural glycosylated flavonoid with antimicrobial, anti-inflammatory, and hypolipidemic effects. This study investigated whether Quer improves dysregulated lipid metabolism and suppresses hepatic steatosis in ovariectomized (OVX) mice as an experimental model mimicking postmenopausal women. Mice were assigned to the following four groups: SHAM, OVX, OVX + β-estradiol (0.4 mg/kg diet), and OVX + Quer (500 mg/kg diet). Mice were administered a diet with or without Quer for three months. OVX mice displayed significantly higher body mass, epidermal fat, and liver weights than those of SHAM mice. However, these levels were reduced in Quer-treated mice. Quer treatment reduced the levels of serum lipid metabolites, including triglycerides, total cholesterol, and low-density lipoprotein cholesterol. Furthermore, Quer reduced liver lipid steatosis and inhibited the expression of proinflammatory cytokines, such as tumor necrosis factor-α, IL-6, and IL-1β. The results of the present study indicate that Quer improves dysregulated lipid metabolism and reduces hepatic steatosis and inflammation by compensating for estrogen deficiency, suggesting that Quer may potentially exert protective effects during hepatic steatosis in postmenopausal women.

Potential Molecular Mechanisms of Zhibai Dihuang Wan in Systemic Lupus Erythematosus Based on Network Biology

Systemic lupus erythematosus (SLE) is a refractory autoimmune disease. Zhibai Dihuang Wan (ZDW) has frequently been used for treating SLE in China and been proved to have a prominent role in decreasing SLE patients’ morality rate. However, the active substances in ZDW and the molecular mechanisms of ZDW in SLE remain unclear. This study identified the bioactive compounds and delineated the molecular targets and potential pathways of ZDW by using a network biology approach. First, we collected putative targets of ZDW based on TCMSP, GeneCards, and STITCH databases and built a network containing the interactions between the putative targets of ZDW and known therapeutic targets of SLE. Then, the key hubs were imported to DAVID Bioinformatics Resources 6.7 to perform gene ontology biological process (GOBP) and pathway enrichment analysis. A total of 95 nodes including 73 putative targets of ZDW were determined as major hubs in terms of their node degree. The results of GOBP and pathway enrichment analysis indicated that putative targets of ZDW mostly were involved in various pathways associated with inflammatory response and apoptosis. More importantly, eleven putative targets of ZDW (CASP3, BCL2, BAX, CYCS, NFKB1, NFKBIA, IL-6, IL-1β, PTGS2, CCL2, and TNF-α) were recognized as active factors involved in the main biological functions of treatment, implying the underlying mechanisms of ZDW acting on SLE. This study provides novel insights into the mechanisms of ZDW in SLE, from the molecular level to the pathway level.

Targeting T Cell Activation and Lupus Autoimmune Phenotypes by Inhibiting Glucose Transporters

CD4⁺ T cells have numerous features of over-activated cellular metabolism in lupus patients and mouse models of the disease. This includes a higher glycolysis than in healthy controls. Glucose transporters play an essential role in glucose metabolism by controlling glucose import into the cell from the extracellular environment. We have previously shown that treatment of lupus-prone mice with 2-deoxy-D-glucose, which inhibits the first step of glycolysis was sufficient to prevent autoimmune activation. However, direct targeting of glucose transporters has never been tested in a mouse model of lupus. Here, we show that CG-5, a novel glucose transporter inhibitor, ameliorated autoimmune phenotypes in a spontaneous lupus-prone mouse model, B6.NZM2410.Sle1.Sle2.Sle3 (Triple-congenic, TC), and in a chronic graft- vs. host-disease (cGVHD) model of induced lupus. In vitro, CG-5 blocked glycolysis in CD4⁺ T cells, and limited the expansion of CD4⁺ T cells induced by alloreactive stimulation. CG-5 also modulated CD4⁺ T cell polarization by inhibiting Th1 and Th17 differentiation and promoting regulatory T (Treg) induction. Moreover, CG-5 treatment reduced lupus phenotypes including the expansion of germinal center B (GC B) cells, as well as the production of autoantibodies in both TC mice and cGVHD models. Finally, CG-5 blocked glycolysis in human T cells. Overall, our data suggest that blocking glucose uptake with a small molecule inhibitor ameliorates autoimmune activation, at least partially due to its inhibition of glycolysis in CD4⁺ T cells.

Inonotus sanghuang Polyphenols Attenuate Inflammatory Response Via Modulating the Crosstalk Between Macrophages and Adipocytes

Aims: Obesity is characterized as a chronic state of low-grade inflammation with progressive immune cell infiltration into adipose tissue. Adipose tissue macrophages play a critical role in the establishment of chronic inflammatory states and metabolic dysfunctions. Inonotus (I.) sanghuang and its extract polyphenols exhibit anti-carcinogenesis, anti-inflammatory, and anti-oxidant activities. However, the action of I. sanghuang polyphenols in obesity-related inflammation has not been reported. The aim of this study was to explore the anti-inflammatory action of polyphenols from I. sanghuang extract (ISE) in macrophages and the interaction between macrophages and adipocytes.

Materials and Methods: RAW264.7 macrophages were stimulated with LPS or conditioned medium of hypertrophied 3T3-L1 adipocytes or cocultured with differentiated adipocytes in the presence of different doses of ISE. The inflammatory cytokines were evaluated by ELISA, the MAPK, NF-κB, and IL-6/STAT3 signals were determined by immunoblotting, and the migrated function of macrophages was determined by migration assay.

Results: ISE suppressed the inflammatory mediators including NO, TNF-α, IL-6, and MCP-1 induced by either LPS or conditioned medium derived from 3T3-L1 adipocytes. ISE also decreased the production of these inflammatory mediators in cocultures of 3T3-L1 adipocytes and RAW264.7 macrophages. Furthermore, ISE blocked RAW264.7 macrophages migration toward 3T3-L1 adipocytes in cocultures. Finally, this effect of ISE might be mediated via inhibiting ERK, p38, and STAT3 activation.

Conclusions: Our findings indicate the possibility that ISE suppresses the interaction between macrophages and adipocytes, attenuates chronic inflammation in adipose tissue and improves obesity-related insulin resistance and complication, suggesting that ISE might be a valuable medicinal food effective in improving insulin resistance and metabolic syndrome.

Flavonoids in Kidney Health and Disease

This review summarizes the latest advances in knowledge on the effects of flavonoids on renal function in health and disease. Flavonoids have antihypertensive, antidiabetic, and antiinflammatory effects, among other therapeutic activities. Many of them also exert renoprotective actions that may be of interest in diseases such as glomerulonephritis, diabetic nephropathy, and chemically-induced kidney insufficiency. They affect several renal factors that promote diuresis and natriuresis, which may contribute to their well-known antihypertensive effect. Flavonoids prevent or attenuate the renal injury associated with arterial hypertension, both by decreasing blood pressure and by acting directly on the renal parenchyma. These outcomes derive from their interference with multiple signaling pathways known to produce renal injury and are independent of their blood pressure-lowering effects. Oral administration of flavonoids prevents or ameliorates adverse effects on the kidney of elevated fructose consumption, high fat diet, and types I and 2 diabetes. These compounds attenuate the hyperglycemia-disrupted renal endothelial barrier function, urinary microalbumin excretion, and glomerular hyperfiltration that results from a reduction of podocyte injury, a determinant factor for albuminuria in diabetic nephropathy. Several flavonoids have shown renal protective effects against many nephrotoxic agents that frequently cause acute kidney injury (AKI) or chronic kidney disease (CKD), such as LPS, gentamycin, alcohol, nicotine, lead or cadmium. Flavonoids also improve cisplatin- or methotrexate-induced renal damage, demonstrating important actions in chemotherapy, anticancer and renoprotective effects. A beneficial prophylactic effect of flavonoids has been also observed against AKI induced by surgical procedures such as ischemia/reperfusion (I/R) or cardiopulmonary bypass. In several murine models of CKD, impaired kidney function was significantly improved by the administration of flavonoids from different sources, alone or in combination with stem cells. In humans, cocoa flavanols were found to have vasculoprotective effects in patients on hemodialysis. Moreover, flavonoids develop antitumor activity against renal carcinoma cells with no toxic effects on normal cells, suggesting a potential therapeutic role in patients with renal carcinoma.

An update on lupus animal models

PURPOSE OF REVIEW

The complexity and heterogeneity of the clinical presentation in systemic lupus of erythematosus (SLE), combined to the inherent limitations of clinical research, have made it difficult to investigate the cause of this disease directly in patients. Various mouse models have been developed to dissect the cellular and genetic mechanisms of SLE, as well as to identify therapeutic targets and to screen treatments. The purpose of this review is to summarize the major spontaneous and induced mouse models of SLE and to provide an update on the major advances they have contributed to the field.

RECENT FINDINGS

Mouse models of SLE have continued to contribute to understand the cellular, signaling and metabolic mechanisms contributing to the disease and how targeting these pathways can provide therapeutic targets. Whenever possible, we discuss the advantage of using one model over the others to test a specific hypothesis.

SUMMARY

Spontaneous and induced models of lupus models are useful tools for the study of the cause of the disease, identify therapeutic targets and screen treatments in preclinical studies. Each model shares specific subsets of attributes with the disease observed in humans, which provides investigators a tool to tailor to their specific needs.

Protective effects of quercetin treatment in a pristane-induced mouse model of lupus nephritis

INTRODUCTION

Lupus nephritis (LN) is one of the most severe complications of systemic lupus erythematosus. As murine models of LN are valuable tools to better understand its pathophysiology and to search for new effective treatments, we investigated the effects of the bioflavonoid quercetin on pristane-induced LN mice through histomorphological analyses.

METHODS

Immunofluorescence and biochemical assays were used to evaluate the expression of markers of inflammation (interleukin-6, IL-6; tumour necrosis factor-α, TNF-α), oxidative stress (catalase, CAT; superoxide dismutase 1, SOD1; thiobarbituric acid reactive substances, TBARS), apoptosis (Bax), and fibrosis (transforming growth factor-β1, TGF-β1). Glomerular and tubular ultrastructure was analysed, and tissue messenger RNA of podocin, podoplanin and α3β1-integrin were quantified using the real-time polymerase chain reaction.

RESULTS

Pristane-induced LN mice showed severe kidney injury, characterized by increased proteinuria, glomerular mesangial expansion and inflammation, high expression of the pro-fibrotic, apoptotic and prooxidant markers and reduction of antioxidants. In the kidney ultrastructure, foot process (FP) effacement, apoptotic mesangial cells and abnormal mitochondria with disrupted cristae were observed, along with suppressed tissue mRNA of podocin, podoplanin and α3β1-integrin. Treatment with quercetin in the pristane-induced LN mice model was nephroprotective, decreasing proteinuria levels and significantly lowering tissue expression of IL-6, TNF-α, TGF-β1, Bax and TBARS. Simultaneously, quercetin significantly increased CAT and SOD1 expressions in these mice. In addition, it was observed improvement of the kidney ultrastructure, and tissue mRNA of podocin, but not podoplanin and α3β1-integrin, was restored to the levels found in the control mice.

CONCLUSION

In conclusion, these findings provide experimental evidence of the renoprotective effects of quercetin in the pristane-induced LN mice model. We suggest that quercetin effectively ameliorates the kidney damage caused by pristane, a bioflavonoid to be further evaluated as a new therapeutic strategy in this disease.