The Role of Short-Chain Fatty Acids in Myocardial Ischemia-Reperfusion Injury.

PURPOSE OF REVIEW: This study aims to review the effects of short-chain fatty acids (SCFAs) in regulating the myocardial ischemia-reperfusion injury (MIRI). RECENT FINDINGS: Coronary heart disease (CHD) is a well-known leading cause of death and disability worldwide. Cardiac substrate metabolism plays the determinant role in assessing the severity of heart injury due to the abruptly shifted energy production during the MIRI. Fatty acids are the main energy fuels for the heart, which are classified into long-, medium- and short chain fatty acids by the length of carbon chain. SCFAs are the main metabolites derived from the anaerobic bacterial fermentation of fiber-rich diets, which are shown to play a protective role in cerebrovascular disease previously. Meanwhile, accumulating evidences suggest that SCFAs can also play a crucial role in cardiac energy metabolism. Results of various studies revealed the cardioprotective effects of SCFAs by displaying anti-inflammatory and anti-ferroptotic function, connecting gut-brain neural circuit and regulating the intestinal flora.

Research Progress on Flavonoids in Traditional Chinese Medicine to Counteract Cardiotoxicity Associated with Anti-Tumor Drugs.

The development of anti-tumor drugs has notably enhanced the survival rates and quality of life for patients with malignant tumors. However, the side effects of these drugs, especially cardiotoxicity, significantly limit their clinical application. The cardiotoxicity associated with anti-tumor drugs has been a subject of extensive attention and research. Traditional to mitigate these side effects have included reducing drug dosages, shortening treatment duration, modifying administration methods, and opting for drugs with lower toxicity. However, either approach may potentially compromise the anti-tumor efficacy of the medications. Therefore, exploring other effective methods for anti-cardiotoxicity will be the focus of future research. The potential of traditional Chinese medicine (TCM) in managing cardiovascular diseases and cancer treatment has gained widespread recognition. TCM is valued for its minimal side effects, affordability, and accessibility, offering promising avenues in the prevention and treatment of cardiotoxicity caused by anti-tumor drugs. Among its constituents, flavonoids, which are present in many TCMs, are particularly notable. These monomeric compounds with distinct structural components have been shown to possess both cardiovascular protective properties and anti-tumor capabilities. In this discussion, we will delve into the classification of anti-tumor drugs and explore the underlying mechanisms of their associated cardiotoxicity. Additionally, we will examine flavonoids found in TCM and investigate their mechanisms of cardiovascular protection. This will include an analysis of how these natural compounds can mitigate the cardiac side effects of anti-tumor therapies while potentially enhancing overall patient health and treatment outcomes.

Evaluation of Radiotherapy Efficacy and Prognostic Analysis for Solid and Cystic Brain Metastases.

OBJECTIVES: Brain metastases (BMs) are commonly categorized into cystic and solid. However, the difference in the prognosis of patients with either cystic or solid BMs following radiotherapy remains poorly understood. We used a retrospective design to elucidate the disparities in survival between these two patient groups undergoing radiotherapy and to identify factors influencing the overall survival (OS) of patients with BMs. METHODS: This retrospective study encompasses 212 patients diagnosed with BMs. We meticulously analyzed the clinical characteristics, radiation therapy modalities, and risk factors influencing the OS among these patients, categorized by BMs type, post-brain radiation therapy. RESULTS: A statistically significant difference in mOS was observed between the two cohorts (Solid vs Cystic: 23.1 vs 14.6 months). Subgroup analysis unveiled distinctions in mOS, particularly in patients with EGFR-mutant lung adenocarcinoma (Solid vs Cystic: 23.1 vs 6.43 months). The volume of BMs and the biological effective dose (BED) emerged as significantly prognostic factors for patients with cystic BMs. For patients with solid BMs, fraction dose, BED, and the number of BMs were identified as independent prognostic factors for survival. CONCLUSION: Brain radiotherapy shows superior survival benefits for lung cancer patients with solid BMs compared to those with cystic BMs, particularly in EGFR-mutant lung cancer. In particular, patients receiving BED ≥60 Gy have a more favorable prognosis than those receiving BED <60 Gy, regardless of the type of BM (solid or cystic) in lung cancer.

Unravelling CD4+ T cell diversity and tissue adaptation of Tregs in abdominal aortic aneurysms through single-cell sequencing.

Immune cell infiltration is a significant pathological process in abdominal aortic aneurysms (AAA). T cells, particularly CD4+ T cells, are essential immune cells responsible for substantial infiltration of the aorta. Regulatory T cells (Tregs) in AAA have been identified as tissue-specific; however, the time, location, and mechanism of acquiring the tissue-specific phenotype are still unknown. Using single-cell RNA sequencing (scRNA-seq) on CD4+ T cells from the AAA aorta and spleen, we discovered heterogeneity among CD4+ T cells and identified activated, proliferating and developed aorta Tregs. These Tregs originate in the peripheral tissues and acquire the tissue-specific phenotype in the aorta. The identification of precursors for Tregs in AAA provides new insight into the pathogenesis of AAA.

Recent advances in potential targets for myocardial ischemia reperfusion injury: Role of macrophages.

Myocardial ischemia-reperfusion injury (MIRI) is a complex process that occurs when blood flow is restored after myocardium infarction (MI) with exacerbated tissue damage. Macrophages, essential cell type of the immune response, play an important role in MIRI. Macrophage subpopulations, namely M1 and M2, are distinguished by distinct phenotypes and functions. In MIRI, macrophages infiltrate in infarcted area, shaping the inflammatory response and influencing tissue healing. Resident cardiac macrophages interact with monocyte-derived macrophages in MIRI, and influence injury progression. Key factors including chemokines, cytokines, and toll-like receptors modulate macrophage behavior in MIRI. This review aims to address recent findings on the classification and the roles of macrophages in the myocardium, spanning from MI to subsequent MIRI, and highlights various signaling pathways implicated in macrophage polarization underlining the complexity of MIRI. This article will shed light on developing advanced therapeutic strategies for MIRI management.

Fulvic acid alleviates the stress of low nitrogen on maize by promoting root development and nitrogen metabolism.

The potential of fulvic acid (FA) to improve plant growth has been acknowledged, but its effect on plant growth and nutrient uptake under nutrient stress remains unclear. This study investigated the effects of different FA application rates on maize growth and nitrogen utilization under low nitrogen stress. The results showed that under low nitrogen stress, FA significantly stimulated maize growth, particularly root development, biomass, and nitrogen content. The enhanced activity levels of key enzymes in nitrogen metabolism were observed, along with differential gene expression in maize, which enriched nitrogen metabolism, amino acid metabolism and plant hormone metabolism. The application of FA regulated the hormones' level, reduced abscisic acid content in leaves and Me-JA content in roots, and increased auxin and zeatin ribose content in leaves. This study concludes that, by promoting root development, nitrogen metabolism, and hormone metabolism, an appropriate concentration of FA can enhance plant tolerance to low nitrogen conditions and improve nitrogen use efficiency.

Single-cell profile reveals the landscape of cardiac immunity and identifies a cardio-protective Ym-1hi neutrophil in myocardial ischemia-reperfusion injury.

Myocardial ischemia-reperfusion injury (MIRI) is a major hindrance to the success of cardiac reperfusion therapy. Although increased neutrophil infiltration is a hallmark of MIRI, the subtypes and alterations of neutrophils in this process remain unclear. Here, we performed single-cell sequencing of cardiac CD45+ cells isolated from the murine myocardium subjected to MIRI at six-time points. We identified diverse types of infiltrating immune cells and their dynamic changes during MIRI. Cardiac neutrophils showed the most immediate response and largest changes and featured with functionally heterogeneous subpopulations, including Ccl3hi Neu and Ym-1hi Neu, which were increased at 6 h and 1 d after reperfusion, respectively. Ym-1hi Neu selectively expressed genes with protective effects and was, therefore, identified as a novel specific type of cardiac cell in the injured heart. Further analysis indicated that neutrophils and their subtypes orchestrated subsequent immune responses in the cardiac tissues, especially instructing the response of macrophages. The abundance of Ym-1hi Neu was closely correlated with the therapeutic efficacy of MIRI when neutrophils were specifically targeted by anti-Lymphocyte antigen 6 complex locus G6D (Ly6G) or anti-Intercellular cell adhesion molecule-1 (ICAM-1) neutralizing antibodies. In addition, a neutrophil subtype with the same phenotype as Ym-1hi Neu was detected in clinical samples and correlated with prognosis. Ym-1 inhibition exacerbated myocardial injury, whereas Ym-1 supplementation significantly ameliorated injury in MIRI mice, which was attributed to the tilt of Ym-1 on the polarization of macrophages toward the repair phenotype in myocardial tissue. Overall, our findings reveal the anti-inflammatory phenotype of Ym-1hi Neu and highlight its critical role in myocardial protection during the early stages of MIRI.

The combination of Tanshinone IIA and Astragaloside IV attenuates myocardial ischemia-reperfusion injury by inhibiting the STING pathway.

BACKGROUND: Astragaloside IV (As-IV) and Tanshinone IIA (Ta-IIA) are the main ingredients of traditional Chinese medicinal Astragalus membranaceus (Fisch.) Bunge and Salvia miltiorrhiza Bunge, respectively, both of which have been employed in the treatment of cardiovascular diseases. Nevertheless, the efficacy of the combination (Co) of Ta-IIA and As-IV for cardiovascular diseases remain unclear and warrant further investigation. This study aimed to investigate the efficacy and the underlying molecular mechanism of Co in treating myocardial ischemia-reperfusion injury (MIRI). METHODS: In order to assess the efficacy of Co, an in vivo MIRI mouse model was created by temporarily blocking the coronary arteries for 30 min and then releasing the blockage. Parameters such as blood myocardial enzymes, infarct size, and ventricular function were measured. Additionally, in vitro experiments were conducted using HL1 cells in both hypoxia-reoxygenation model and oxidative stress models. The apoptosis rate, expression levels of apoptosis-related proteins, oxidative stress indexes, and release of inflammatory factors were detected. Furthermore, molecular docking was applied to examine the binding properties of Ta-IIA and As-IV to STING, and western blotting was performed to analyze protein expression of the STING pathway. Additionally, the protective effect of Ta-IIA, As-IV and Co via inhibiting STING was further confirmed in models of knockdown STING by siRNA and adding STING agonist. RESULTS: Both in vitro and in vivo data demonstrated that, compared to Ta-IIA or As-IV alone, the Co exhibited superior efficacy in reducing the area of myocardial infarction, lowering myocardial enzyme levels, and promoting the recovery of myocardial contractility. Furthermore, the Co showed more potent anti-apoptosis, antioxidant, and anti-inflammation effects. Additionally, the Co enhanced the inhibitory effects of Ta-IIA and As-IV on STING phosphorylation and the activation of STING signaling pathway. However, the administration of a STING agonist attenuated the protective effects of the Co, Ta-IIA, and As-IV by compromising their anti-apoptotic, antioxidant, and anti-inflammatory effects in MIRI. CONCLUSION: Compared to the individual administration of Ta-IIA or As-IV, the combined treatment demonstrated more potent ability in inhibiting apoptosis, oxidative stress, inflammation, and the STING signaling pathway in the context of MIRI, indicating a more powerful protective effect against MIRI.

Amphiregulin improves ventricular remodeling after myocardial infarction by modulating autophagy and apoptosis.

Myocardial infarction (MI) is defined as sudden ischemic death of myocardial tissue. Amphiregulin (Areg) regulates cell survival and is crucial for the healing of tissues after damage. However, the functions and mechanisms of Areg after MI remain unclear. Here, we aimed to investigate Areg's impact on myocardial remodeling. Mice model of MI was constructed and Areg-/- mice were used. Expression of Areg was analyzed using western blotting, RT-qPCR, flow cytometry, and immunofluorescence staining. Echocardiographic analysis, Masson's trichrome, and triphenyltetrazolium chloride staining were used to assess cardiac function and structure. RNA sequencing was used for unbiased analysis. Apoptosis and autophagy were determined by western blotting, TUNEL staining, electron microscopy, and mRFP-GFP-LC3 lentivirus. Lysosomal acidity was determined by Lysotracker staining. Areg was elevated in the infarct border zone after MI. It was mostly secreted by macrophages. Areg deficiency aggravated adverse ventricular remodeling, as reflected by worsening cardiac function, a lower survival rate, increased scar size, and interstitial fibrosis. RNA sequencing analyses showed that Areg related to the epidermal growth factor receptor (EGFR), phosphoinositide 3-kinase/protein kinase B (PI3K-Akt), mammalian target of rapamycin (mTOR) signaling pathways, V-ATPase and lysosome pathways. Mechanistically, Areg exerts beneficial effects via increasing lysosomal acidity to promote autophagosome clearance, and activating the EGFR/PI3K/Akt/mTOR signaling pathway, subsequently inhibiting excessive autophagosome formation and apoptosis in cardiomyocytes. This study provides a novel evidence for the role of Areg in inhibiting ventricular remodeling after MI by regulating autophagy and apoptosis and identifies Areg as a potential therapeutic target in ventricular remodeling after MI.

Bioinformatics and experimental studies jointly reveal that Sacubitril Valsartan improves myocardial oxidative stress and inflammation by regulating the MAPK signaling pathway to treat chemotherapy related cardiotoxicity.

BACKGROUND: CRC is a common but serious complication or sequela of tumor treatment, and new coping strategies are urgently needed. SV is a classic clinical cardiovascular protective drug, which has been widely used in the treatment of heart failure, hypertension and other diseases. It has good therapeutic effect in other cardiovascular diseases such as diabetes cardiomyopathy, ischemic cardiomyopathy and vascular disease, but it has not been proved by research that SV can prevent and treat CRC. METHOD: In this study, DOX was used to induce a rat CRC model and evaluate the therapeutic effect of SV on it. Subsequently, R software was applied to analyze the control group, SV group, and DOX group in databases GSE207283 and GSE22369, and to screen for common differentially expressed genes. Use the DAVID website for enrichment analysis and visualization. Use STRING website to analyze and visualize protein interaction networks of key genes. Finally, experimental verification was conducted on key genes. RESULT: Our research results show that SV has a protective effect on DOX induced myocardial injury by alleviating Weight loss, increasing Ejection fraction, and reducing the level of biomarkers of myocardial injury. Meanwhile, SV can effectively alleviate the above abnormalities. Bioinformatics and KEGG pathway analysis showed significant enrichment of metabolic and MAPK signaling pathways, suggesting that they may be the main regulatory pathway for SV treatment of CRC. Subsequent studies have also confirmed that SV can inhibit DOX induced myocardial injury through the MAPK signaling pathway, and alleviate DOX induced oxidative stress and inflammatory states. CONCLUSION: Our research indicates that SV is a potential drug for treating CRC and preliminarily elucidates its molecular mechanism of regulating the MAPK pathway to improve oxidative stress and inflammation.

JAK-STAT signaling in inflammation and stress-related diseases: implications for therapeutic interventions.

The Janus kinase-signal transducer and transcription activator pathway (JAK-STAT) serves as a cornerstone in cellular signaling, regulating physiological and pathological processes such as inflammation and stress. Dysregulation in this pathway can lead to severe immunodeficiencies and malignancies, and its role extends to neurotransduction and pro-inflammatory signaling mechanisms. Although JAK inhibitors (Jakinibs) have successfully treated immunological and inflammatory disorders, their application has generally been limited to diseases with similar pathogenic features. Despite the modest expression of JAK-STAT in the CNS, it is crucial for functions in the cortex, hippocampus, and cerebellum, making it relevant in conditions like Parkinson's disease and other neuroinflammatory disorders. Furthermore, the influence of the pathway on serotonin receptors and phospholipase C has implications for stress and mood disorders. This review expands the understanding of JAK-STAT, moving beyond traditional immunological contexts to explore its role in stress-related disorders and CNS function. Recent findings, such as the effectiveness of Jakinibs in chronic conditions such as rheumatoid arthritis, expand their therapeutic applicability. Advances in isoform-specific inhibitors, including filgotinib and upadacitinib, promise greater specificity with fewer off-target effects. Combination therapies, involving Jakinibs and monoclonal antibodies, aiming to enhance therapeutic specificity and efficacy also give great hope. Overall, this review bridges the gap between basic science and clinical application, elucidating the complex influence of the JAK-STAT pathway on human health and guiding future interventions.

Early-life maternal deprivation in rats increases sensitivity to the subsequent stressors: a pilot study.

Early life experiences, particularly maternal deprivation (MD), have long-lasting implications on emotional and cognitive development. Using Wistar rats as a model, this study explores the impact of MD followed by predator stress exposure (PSS) to simulate aspects of post-traumatic stress disorder (PTSD). A cohort of 41 male rat pups underwent MD from postnatal days 2 to 14, followed by PSS at day 90. Female rat pups were not included in the experiment. Behavior was subsequently assessed using the Elevated Plus Maze test 14 days post-PSS. While MD led to subtle changes such as decreased activity and increased anxiety-like behavior, PSS induced pronounced anxiogenic effects. Notably, PSS after MD resulted in decreased basal corticosterone levels, mirroring conditions observed in PTSD. The findings suggest that although MD itself does not induce significant behavioral changes, it predisposes individuals to heightened sensitivity to subsequent stressors. This study underscores the utility of a two-stage PSS model for more accurately reflecting the complexities inherent in stress-related disorders, including PTSD.

Latency-associated peptide (LAP)+CD4+ regulatory T cells prevent atherosclerosis by modulating macrophage polarization.

RATIONALE: A persistent autoimmune and inflammatory response plays a critical role in the progression of atherosclerosis. The transcription factor forkhead box P3 (Foxp3)+CD4+ regulatory T cells (Foxp3+ Tregs) attenuate atherosclerosis. Latency-associated peptide (LAP)+CD4+ T cells are a new class of Tregs whose role in atherosclerosis is unknown. OBJECTIVE: To investigate the function of CD4+LAP+ Tregs in inhibiting inflammation and preventing atherosclerosis. METHODS AND RESULTS: Depletion of CD4+LAP+ Tregs results in aggravated inflammation and atherosclerotic lesions. Mechanistically, CD4+LAP+ Treg depletion was associated with decreased M2-like macrophages and increased Th1 and Th17 cells, characterized by increased unstable plaque promotion and decreased expression of inflammation-resolving factors in both arteries and immune organs. In contrast, adoptive transfer of CD4+LAP+ Tregs to ApoE-/- mice or CD4-/-ApoE-/- mice led to decreased atherosclerotic lesions. Compared with control animals, adoptive transfer of CD4+LAP+ Tregs induced M2-like macrophage differentiation within the atherosclerotic lesion and spleen, associated with increased collagen and α-SMA in plaques and decreased expression of MMP-2 and MMP-9. Mechanistic studies reveal that isolated CD4+LAP+ Tregs exhibit a tolerance phenotype, with increased expression of inhibitory cytokines and coinhibitory molecules. After coculture with CD4+LAP+ Tregs, monocytes/macrophages display typical features of M2 macrophages, including upregulated expression of CD206 and Arg-1 and decreased production of MCP-1, IL-6, IL-1ß and TNF-α, which was almost abrogated by transwell and partially TGF-ß1 neutralization. RNA-seq analysis showed different gene expression profiles between CD4+LAP+ Tregs and LAP-CD4+ T cells and between CD4+LAP+ Tregs of ApoE-/- mice and CD4+LAP+ Tregs of C57BL/6 mice, of which Fancd2 and IL4i1 may contribute to the powerful inhibitory properties of CD4+LAP+ Tregs. Furthermore, the number and the suppressive properties of CD4+LAP+ Tregs were impaired by oxLDL. CONCLUSIONS: Our data indicate that the remaining CD4+LAP+ Tregs play a protective role in atherosclerosis by modulating monocyte/macrophage differentiation and regulatory factors, which may partly explain the protective effect of T cells tolerance in atherosclerosis. Moreover, adoptive transfer of CD4+LAP+ Tregs constitutes a novel approach to treat atherosclerosis.

Genome-Wide Identification and Functional Analysis of Nitrate Transporter Genes (NPF, NRT2 and NRT3) in Maize.

Nitrate is the primary form of nitrogen uptake in plants, mainly transported by nitrate transporters (NRTs), including NPF (NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER FAMILY), NRT2 and NRT3. In this study, we identified a total of 78 NPF, seven NRT2, and two NRT3 genes in maize. Phylogenetic analysis divided the NPF family into eight subgroups (NPF1-NPF8), consistent with the results in Arabidopsis thaliana and rice. The NRT2 family appears to have evolved more conservatively than the NPF family, as NRT2 genes contain fewer introns. The promoters of all NRTs are rich in cis-acting elements responding to biotic and abiotic stresses. The expression of NRTs varies in different tissues and developmental stages, with some NRTs only expressed in specific tissues or developmental stages. RNA-seq analysis using Xu178 revealed differential expression of NRTs in response to nitrogen starvation and nitrate resupply. Moreover, the expression patterns of six key NRTs genes (NPF6.6, NPF6.8, NRT2.1, NRT2.5 and NRT3.1A/B) varied in response to alterations in nitrogen levels across distinct maize inbred lines with different nitrogen uptake rates. This work enhances our understanding of the structure and expression of NRTs genes, and their roles in nitrate response, paving the way for improving maize nitrogen efficiency through molecular breeding.

zma-miR159 targets ZmMYB74 and ZmMYB138 transcription factors to regulate grain size and weight in maize.

Endosperm cell number is critical in determining grain size in maize (Zea mays). Here, zma-miR159 overexpression led to enlarged grains in independent transgenic lines, suggesting that zma-miR159 contributes positively to maize grain size. Targeting of ZmMYB74 and ZmMYB138 transcription factor genes by zma-miR159 was validated using 5' RACE and dual-luciferase assay. Lines in which ZmMYB74 was knocked out using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) presented a similar enlarged grain phenotype as those with zma-miR159 overexpression. Downstream genes regulating cell division were identified through DNA affinity purification sequencing using ZmMYB74 and ZmMYB138. Our results suggest that zma-miR159-ZmMYB modules act as an endosperm development hub, participating in the division and proliferation of endosperm cells.

Involved site radiation therapy in stage I-III nasopharyngeal carcinoma with limited lymph node burden (ISRT-NPC) or elective region irradiation: a study protocol for a multicenter non-inferiority randomized controlled phase III clinical trial.

BACKGROUND: Current radiotherapy guidelines and consensus statements uniformly recommend elective region irradiation (ERI) as the standard strategy for nasopharyngeal carcinoma (NPC). However, given the scarcity of skip-metastasis, the improved assessment accuracy of nodal involvement, and the striking advancements in chemotherapy for NPC, a one-fits-all delineation scheme for clinical target volumes of the nodal region (CTVn) may not be appropriate anymore, and modifications of the CTVn delineation strategy may be warranted. Involved site irradiation (ISI) covering merely the initially involved nodal site and potential extranodal extension has been confirmed to be as effective as ERI with decreased radiation-related toxicities in some malignancies, but has not yet been investigated in NPC. This study aims to compare the regional control, survival outcomes, radiation-related toxicities, and quality of life (QoL) of ISI with conventional ERI in NPC patients with a limited nodal burden. METHODS: ISRT-NPC is a prospective, multicenter, open-label, noninferiority, phase III randomized controlled trial. A total of 414 patients will be randomly assigned in a 1:1 ratio to receive ISI or ERI. Randomization will be stratified by institution scale and N stage. Generally, in the ISI group, the high-risk CTV1 (dose: 60 Gy) includes a 1-cm expansion of the positive LN as well as the VIIa and the retrostyloid space above the bilateral transverse process of the atlantoaxial spine (C1), regardless of N status. The low-risk CTV2 (dose: 50 Gy) covers the cervical nodal region with a 3-cm caudal expansion below the transverse process of C1 for N0 disease and a 3-cm expansion below the positive LN for positive LNs. DISCUSSION: The results of this trial are expected to confirm that ISI is a non-inferior strategy to ERI in stage I-III patients with low LN burden, enabling the minimization of treatment-related toxicity and improvement of long-term QoL without compromising regional control. TRIAL REGISTRATION: ClinicalTrails.gov, NCT05145660. Registered December 6, 2021.

Sequence Variation of Candida albicans Sap2 Enhances Fungal Pathogenicity via Complement Evasion and Macrophage M2-Like Phenotype Induction.

Candida albicans (C. albicans) is an opportunistic pathogen increasingly causing candidiasis worldwide. This study aims to investigate the pattern of systemic immune responses triggered by C. albicans with disease associated variation of Sap2, identifying the novel evasion strategies utilized by clinical isolates. Specifically, a variation in clinical isolates is identified at nucleotide position 817 (G to T). This homozygous variation causes the 273rd amino acid exchange from valine to leucine, close to the proteolytic activation center of Sap2. The mutant (Sap2-273L) generated from SC5314 (Sap2-273V) background carrying the V273L variation within Sap2 displays higher pathogenicity. In comparison to mice infected with Sap2-273V strain, mice infected with Sap2-273L exhibit less complement activation indicated by less serum C3a generation and weaker C3b deposition in the kidney. This inhibitory effect is mainly achieved by Sap2273L -mediated stronger degradation of C3 and C3b. Furthermore, mice infected with Sap2-273L strain exhibit more macrophage phenotype switching from M0 to M2-like and more TGF-ß release which further influences T cell responses, generating an immunosuppressed cellular microenvironment characterized by more Tregs and exhausted T cell formation. In summary, the disease-associated sequence variation of Sap2 enhances pathogenicity by complement evasion and M2-like phenotype switching, promoting a more efficient immunosuppressed microenvironment.

Quercetin serves as the major component of Xiang-lian Pill to ameliorate ulcerative colitis via tipping the balance of STAT1/PPARγ and dictating the alternative activation of macrophage.

ETHNOPHARMACOLOGICAL RELEVANCE: The traditional Chinese herbal formula, Xiang-lian Pill (XLP), is commonly prescribed for ulcerative colitis (UC) patients to relieve their clinical symptom. Nonetheless, the underlying cellular and molecular mechanisms of XLP's anti-UC effect remain incompletely understood. AIM OF THE STUDY: To evaluate the therapeutic effect and elucidate the possible working mechanisms of XLP in UC treatment. The major active component of XLP was also characterized. MATERIALS AND METHODS: Colitis was induced in C57BL/6 mice with 3% dextran sulfate sodium (DSS) dissolved in drinking water for 7 consecutive days. The UC mice were grouped and treated with XLP (3640 mg/kg) or vehicle orally during the procedure of DSS induction. Mouse body weight, disease activity index (DAI) score and colon length were recorded. Histopathological changes and inflammatory cell infiltration were evaluated by pathological staining and flow cytometric analysis (FACS). Network pharmacology, bioinformatic analysis, widely targeted and targeted metabolomics analysis were performed to screen the potential effective ingredients and key targets. Bone marrow derived macrophages (BMDMs), peripheral blood mononuclear cells (PBMCs), RAW264.7 and THP-1 cells were used to dissect the anti-inflammatory effect of XLP. RESULTS: Oral administration of XLP ameliorated DSS induced mouse colitis, as evidenced by reduced DAI and colonic inflammatory destruction. FACS results demonstrated that XLP treatment effectively restored immune tolerance in colon, inhibited the generation of monocyte derived macrophages and skewed macrophage polarization into M2 phenotype. Network pharmacology analysis suggested that innate effector modules related to macrophage activation comprise the major targets of XLP, and the counter-regulatory STAT1/PPARγ signaling possibly serves as the critical downstream pathway. Subsequent experiments unveiled an imbalance of STAT1/PPARγ signaling in monocytes derived from UC patients, and validated that XLP suppressed LPS/IFN-γ induced macrophage activation (STAT1 mediated) but facilitated IL-4 induced macrophage M2 polarization (PPARγ dependent). Meanwhile, our data showed that quercetin served as the major component of XLP to recapitulate the regulatory effect on macrophages. CONCLUSION: Our findings revealed that quercetin serves as the major component of XLP that regulates macrophage alternative activation via tipping the balance of STAT1/PPARγ, which provides a mechanistic explanation for the therapeutic effect of XLP in UC treatment.