The Role of Notch Signaling in Macrophages during Inflammation and Infection: Implication in Rheumatoid Arthritis?

Canonical notch activation in patients with scrub typhus: association with organ dysfunction and poor outcome

PURPOSE

The mechanisms that control inflammation in scrub typhus are not fully elucidated. The Notch pathways are important regulators of inflammation and infection, but have not been investigated in scrub typhus.

METHODS

Plasma levels of the canonical Notch ligand Delta-like protein 1 (DLL1) were measured by enzyme immunoassay and RNA expression of the Notch receptors (NOTCH1, NOTCH2 and NOTCH4) in whole blood was analyzed by real-time PCR in patients with scrub typhus (n = 129), in patients with similar febrile illness without O. tsutsugamushi infection (n = 31) and in healthy controls (n = 31); all from the same area of South India.

RESULTS

Our main results were: (i) plasma DLL1 was markedly increased in scrub typhus patients at hospital admission with a significant decrease during recovery. (ii) RNA expression of NOTCH4 was decreased at admission in whole blood. (iii) A similar pattern for DLL1 and NOTCH4 was seen in febrile disease controls. (iv) Admission DLL1 in plasma was associated with disease severity and short-term survival. (vi) Regulation of Notch pathways in O. tsutsugamushi-infected monocytes as evaluated by public repository data revealed enhanced canonical Notch activation with upregulation of DLL1 and downregulation of NOTCH4.

CONCLUSION

Our findings suggest that scrub typhus patients are characterized by enhanced canonical Notch activation. Elevated plasma levels of DLL1 were associated with organ dysfunction and poor outcomes in these patients.

DAP12 interacts with RER1 and is retained in the secretory pathway before assembly with TREM2

DNAX-activating protein of 12 kDa (DAP12) is a transmembrane adapter protein expressed in lymphoid and myeloid lineage cells. It interacts with several immunoreceptors forming functional complexes that trigger intracellular signaling pathways. One of the DAP12 associated receptors is the triggering receptor expressed on myeloid cells 2 (TREM2). Mutations in both DAP12 and TREM2 have been linked to neurodegenerative diseases. However, mechanisms involved in the regulation of subcellular trafficking and turnover of these proteins are not well understood. Here, we demonstrate that proteasomal degradation of DAP12 is increased in the absence of TREM2. Interestingly, unassembled DAP12 is also retained in early secretory compartments, including the endoplasmic reticulum (ER) and the ER-Golgi intermediate compartment (ERGIC), thereby preventing its transport to the plasma membrane. We also show that unassembled DAP12 interacts with the retention in ER sorting receptor 1 (RER1). The deletion of endogenous RER1 decreases expression of functional TREM2-DAP12 complexes and membrane proximal signaling, and resulted in almost complete inhibition of phagocytic activity in THP-1 differentiated macrophage-like cells. These results indicate that RER1 acts as an important regulator of DAP12 containing immunoreceptor complexes and immune cell function.

Lignin-cellulose complexes derived from agricultural wastes for combined antibacterial and tissue engineering scaffolds for cutaneous leishmaniasis wounds

Bacterial infections in wounds significantly impair the healing process. The use of natural antibacterial products over synthetic antibiotics has emerged as a new trend to address antimicrobial resistance. An ideal tissue engineering scaffold to treat infected wounds should possess antibacterial properties, while simultaneously promoting tissue regrowth. Synthesis of hydrogel scaffolds with antibacterial properties using hemp shive (HT1/HT2) lignin, sugarcane bagasse (SCB) lignin and cellulose was carried out. All lignin samples had low molecular weights and were constituted of G-type β-5 dimers, linked by β-O-4 bonds, as determined by MALDI-TOF-MS. Hemp lignin was more cytotoxic to mouse fibroblasts (L929) compared to SCB lignin. All lignin samples demonstrated antibacterial properties against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis, with greater efficiency against Gram-negative strains. 3D hydrogels were engineered by crosslinking SCB lignin with SCB cellulose in varying weight ratios in the presence of epichlorohydrin. The stiffness of the hydrogels could be tailored by varying the lignin concentration. All hydrogels were biocompatible; however, better fibroblast adhesion was observed on the blended hydrogels compared to the 100% cellulose hydrogel, with the cellulose : lignin 70 : 30 hydrogel showing the highest L929 proliferation and best antibacterial properties with a 24-hour bacterial growth reduction ranging from 30.8 to 57.3%.

New Therapeutic Strategies for the Inflammatory Rheumatoid Arthritis Disease: Emphasizing Mesenchymal Stem Cells and Associated exo-miRNA or exo-lncRNA

The most prevalent inflammatory arthritis and a leading contributor to disability is rheumatoid arthritis (RA). Although it may not have arrived in Europe until the 17th century, it was present in early Native American communities several thousand years ago. Exosomes released by mesenchymal stem cells (MSCs) are highly immunomodulatory due to the origin of the cell. As a cell-free therapy, MSCs-exosomes are less toxic and elicit a weakened immune response than cell-based therapies. Exosomal noncoding RNAs (ncRNAs) are closely associated with a number of biological and functional facets of human health, especially microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). Various exo-miRNAs and lncRNAs such as HAND2-AS1, miR-150-5p, miRNA-124a, and miR-320a lodged with MSC could be appropriate therapeutic ways for RA treatment. These MSC-derived exosomes affect RA disorders via different molecular pathways such as NFK-β, MAPK, and Wnt. The purpose of this review is to review the research that has been conducted since 2020 so far in the field of RA disease treatment with MSC-loaded exo-miRNAs and exo-lncRNAs.

RBPJ Knockdown Promotes M2 Macrophage Polarization Through Mitochondrial ROS-mediated Notch1-Jagged1-Hes1 Signaling Pathway in Uveitis

Uveitis is an autoimmune eye disease that can be involved in the entire body and is one of the leading causes of blindness. Therefore, comprehending the mechanisms underlying the development and regulation of ocular immune responses in uveitis is crucial for designing effective therapeutic interventions. In this study, we investigated how RBPJ regulates macrophage polarization in uveitis. We demonstrated that targeted RBPJ knockdown (RBPJKD) promotes M2 macrophage polarization and ameliorates uveitis through the mtROS-mediated Notch1-Jagged1-Hes1 signaling pathway. Real-time quantitative (Q-PCR) analysis revealed that the Notch1-Jagged1-Hes1 signaling pathway was active in the eye tissues of experimental autoimmune uveitis (EAU) rats. Immunofluorescence double staining confirmed enhanced signaling primarily occurring in macrophages, establishing a correlation between the Notch1 signaling pathway and macrophages. Transmission electron microscopy evaluated the morphological and functional changes of mitochondria in each group's eye tissues. It demonstrated significant swelling and disorganization in the EAU group, which were effectively restored upon RBPJ knockdown intervention. Finally, by employing an antioxidant N-acetyl-L-cysteine (NAC) to eliminate mtROS in vivo, we observed a decrease in the M2 macrophage polarization level, which prevented the cytoprotective effect conferred by RBPJKD. These findings underscore the relevance of the Notch signaling pathway to the immune system while highlighting the potential role of mtROS as a therapeutic target for inflammation and other related diseases.

The role of the Notch signaling pathway in bacterial infectious diseases

The Notch signaling pathway is the most crucial link in the normal operation and maintenance of physiological functions of mammalian life processes. Notch receptors interact with ligands and this leads to three cleavages and goes on to enter the nucleus to initiate the transcription of target genes. The Notch signaling pathway deeply participates in the differentiation and function of various cells, including immune cells. Recent studies indicate that the outcomes of Notch signaling are changeable and highly dependent on different bacterial infection. The Notch signaling pathway plays a different role in promoting and inhibiting bacterial infection. In this review, we focus on the latest research findings of the Notch signaling pathway in bacterial infectious diseases. The Notch signaling pathway is critically involved in a variety of development processes of immunosuppression of different APCs. The Notch signaling pathway leads to functional changes in epithelial cells to aggravate tissue damage. Specifically, we illustrate the regulatory mechanism of the Notch signaling pathway in various bacterial infections, such as Mycobacterium tuberculosis, Mycobacterium avium paratuberculosis, Mycobacterium leprae, Helicobacter pylori, Klebsiella pneumoniae, Bacillus subtilis, Staphylococcus aureus, Ehrlichia chaffeensis and sepsis. Collectively, this review will not only help beginners intuitively and systematically understand the Notch signaling pathway in bacterial infectious diseases but also help experts to generate fresh insight in this field.

Immunomodulatory effects of curcumin on macrophage polarization in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by synovial inflammation, cartilage destruction, pannus formation and bone erosion. Various immune cells, including macrophages, are involved in RA pathogenesis. The heterogeneity and plasticity of macrophages render them pivotal regulators of both the induction and resolution of the inflammatory response. Predominantly, two different phenotypes of macrophages have been identified: classically activated M1 macrophages exacerbate inflammation via the production of cytokines, chemokines and other inflammatory mediators, while alternatively activated M2 macrophages inhibit inflammation and facilitate tissue repair. An imbalance in the M1/M2 macrophage ratio is critical during the initiation and progression of RA. Macrophage polarization is modulated by various transcription factors, epigenetic elements and metabolic reprogramming. Curcumin, an active component of turmeric, exhibits potent immunomodulatory effects and is administered in the treatment of multiple autoimmune diseases, including RA. The regulation of macrophage polarization and subsequent cytokine production as well as macrophage migration is involved in the mechanisms underlying the therapeutic effect of curcumin on RA. In this review, we summarize the underlying mechanisms by which curcumin modulates macrophage function and polarization in the context of RA to provide evidence for the clinical application of curcumin in RA treatment.

Large-scale computational modelling of the M1 and M2 synovial macrophages in rheumatoid arthritis

Macrophages play an essential role in rheumatoid arthritis. Depending on their phenotype (M1 or M2), they can play a role in the initiation or resolution of inflammation. The M1/M2 ratio in rheumatoid arthritis is higher than in healthy controls. Despite this, no treatment targeting specifically macrophages is currently used in clinics. Thus, devising strategies to selectively deplete proinflammatory macrophages and promote anti-inflammatory macrophages could be a promising therapeutic approach. State-of-the-art molecular interaction maps of M1 and M2 macrophages in rheumatoid arthritis are available and represent a dense source of knowledge; however, these maps remain limited by their static nature. Discrete dynamic modelling can be employed to study the emergent behaviours of these systems. Nevertheless, handling such large-scale models is challenging. Due to their massive size, it is computationally demanding to identify biologically relevant states in a cell- and disease-specific context. In this work, we developed an efficient computational framework that converts molecular interaction maps into Boolean models using the CaSQ tool. Next, we used a newly developed version of the BMA tool deployed to a high-performance computing cluster to identify the models' steady states. The identified attractors are then validated using gene expression data sets and prior knowledge. We successfully applied our framework to generate and calibrate the M1 and M2 macrophage Boolean models for rheumatoid arthritis. Using KO simulations, we identified NFkB, JAK1/JAK2, and ERK1/Notch1 as potential targets that could selectively suppress proinflammatory macrophages and GSK3B as a promising target that could promote anti-inflammatory macrophages in rheumatoid arthritis.

Targeting Pathways and Integrated Approaches to Treat Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic symmetrical systemic disorder that not only affects joints but also other organs such as heart, lungs, kidney, and liver. Approximately there is 0.5%-1% of the total population affected by RA. RA pathogenesis still remains unclear due to which its appropriate treatment is a challenge. Further, multitudes of factors have been reported to affect its progression i.e. genetic factor, environmental factor, immune factor, and oxidative factor. Therapeutic approaches available for the treatment of RA include NSAIDs, DMARDs, enzymatic, hormonal, and gene therapies. But most of them provide the symptomatic relief without treating the core of the disease. This makes it obligatory to explore and reach the molecular targets for cure and long-term relief from RA. Herein, we attempt to provide extensive overlay of the new targets for RA treatment such as signaling pathways, proteins, and receptors affecting the progression of the disease and its severity. Precise modification in these targets such as suppressing the notch signaling pathway, SIRT 3 protein, Sphingosine-1-phosphate receptor and stimulating the neuronal signals particularly efferent vagus nerve and SIRT 1 protein may offer long term relief and potentially diminish the chronicity. To target or alter the novel molecules and signaling pathway a specific delivery system is required such as liposome, nanoparticles and micelles and many more. Present review paper discusses in detail about novel targets and delivery systems for treating RA.

Polarization of M2 Tumor-Associated Macrophages (TAMs) in Cancer Immunotherapy

We have witnessed in the last decade new milestones in the treatment of various resistant cancers with new immunotherapeutic modalities. These advances have resulted in significant objective durable clinical responses in a subset of cancer patients. These findings strongly suggested that immunotherapy should be considered for the treatment of all subsets of cancer patients. Accordingly, the mechanisms underlying resistance to immunotherapy must be explored and develop new means to target these resistant factors. One of the pivotal resistance mechanisms in the tumor microenvironment (TME) is the high infiltration of tumor-associated macrophages (TAMs) that are highly immunosuppressive and responsible, in large part, of cancer immune evasion. Thus, various approaches have been investigated to target the TAMs to restore the anti-tumor immune response. One approach is to polarize the M2 TAMS to the M1 phenotype that participates in the activation of the anti-tumor response. In this review, we discuss the various and differential properties of the M1 and M2 phenotypes, the molecular signaling pathways that participate in the polarization, and various approaches used to target the polarization of the M2 TAMs into the M1 anti-tumor phenotype. These approaches include inhibitors of histone deacetylases, PI3K inhibitors, STAT3 inhibitors, TLR agonists, and metabolic reprogramming. Clearly, due to the distinct features of various cancers and their heterogeneities, a single approach outlined above might only be effective against some cancers and not others. In addition, targeting by itself may not be efficacious unless used in combination with other therapeutic modalities.

Exploring the causal relationship between inflammatory cytokines and inflammatory arthritis: A Mendelian randomization study

OBJECTIVES

Previous studies have reported an association between inflammatory cytokines and inflammatory arthritis, including Ankylosing spondylitis (AS), rheumatoid arthritis (RA), and psoriatic arthritis (PsA). This study aims to explore the causal relationship between inflammatory cytokines and AS, RA, and PsA using Mendelian randomization (MR).

METHODS

We conducted a bidirectional two-sample MR analysis using genetic summary data from a publicly available genome-wide association study (GWAS) that included 41 genetic variations of inflammatory cytokines, as well as genetic variant data for AS, RA, and PsA from the FinnGen consortium. The main analysis method used was Inverse variance weighted (IVW) to investigate the causal relationship between exposure and outcome. Additionally, other methods such as MR Egger, weighted median (WM), simple mode, and weighted mode were employed to strengthen the final results. Sensitivity analysis was also performed to ensure the reliability of the findings.

RESULTS

The results showed that macrophage colony-stimulating factor (MCSF) was associated with an increased risk of AS (OR = 1.163, 95 % CI = 1.016-1.33, p = 0.028). Conversely, high levels of TRAIL and beta nerve growth factor (β-NGF) were associated with a decreased risk of AS (OR = 0.892, 95 % CI = 0.81-0.982, p = 0.002; OR = 0.829, 95 % CI = 0.696-0.988, p = 0.036). Four inflammatory cytokines were found to be associated with an increased risk of PsA: vascular endothelial growth factor (VEGF) (OR = 1.161, 95 % CI = 1.057-1.275, p = 0.002); Interleukin 12p70 (IL12p70) (OR = 1.189, 95 % CI = 1.049-1.346, p = 0.007); IL10 (OR = 1.216, 95 % CI = 1.024-1.444, p = 0.026); IL13 (OR = 1.159, 95 % CI = 1.05-1.28, p = 0.004). Interleukin 1 receptor antagonist (IL-1rα) was associated with an increased risk of seropositive RA (OR = 1.181, 95 % CI = 1.044-1.336, p = 0.008). Similarly, genetic susceptibility to inflammatory arthritis was found to be causally associated with multiple inflammatory cytokines. Lastly, the sensitivity analysis supported the robustness of these findings.

CONCLUSIONS

This study provides additional insights into the relationship between inflammatory cytokines and inflammatory arthritis, and may offer new clues for the etiology, diagnosis, and treatment of inflammatory arthritis.

Insights into the Notch signaling pathway in degenerative musculoskeletal disorders: Mechanisms and perspectives

Degenerative musculoskeletal disorders are a group of age-related diseases of the locomotive system that severely affects the patient's ability to work and cause adverse sequalae such as fractures and even death. The incidence and prevalence of degenerative musculoskeletal disorders is rising owing to the aging of the world's population. The Notch signaling pathway, which is expressed in almost all organ systems, extensively regulates cell proliferation and differentiation as well as cellular fate. Notch signaling shows increased activity in degenerative musculoskeletal disorders and retards the progression of degeneration to some extent. The review focuses on four major degenerative musculoskeletal disorders (osteoarthritis, intervertebral disc degeneration, osteoporosis, and sarcopenia) and summarizes the pathophysiological functions of Notch signaling in these disorders, especially its role in stem/progenitor cells in each disorder. Finally, a conclusion will be presented to explore the research and application of the perspectives on Notch signaling in degenerative musculoskeletal disorders.

MiR-223-3p attenuates M1 macrophage polarization via suppressing the Notch signaling pathway and NLRP3-mediated pyroptosis in experimental autoimmune uveitis

Autoimmune uveitis is an intraocular inflammatory disease with a high blindness rate in developed countries such as the United States. It is pressing to comprehend the pathogenesis of autoimmune uveitis and develop novel schemes for its treatment. In the present research, we demonstrated that the Notch signaling pathway was activated, and the level of miR-223-3p was significantly reduced in rats with experimental autoimmune uveitis (EAU) compared with the level of normal rats. To investigate the relationship between miR-223-3p and Notch signaling, EAU rats received miR-223-3p-carrying lentivirus, miR-223-3p vector-carrying lentivirus (miR-223-3p-N), and γ-secretase inhibitor (DAPT), respectively. The results of Q-PCR, immunological experiments, and flow cytometry analysis all support the hypothesis that both miR-223-3p and DAPT, a Notch signaling pathway inhibitor, had similar inhibitory effects on the EAU pathological process. That is to say, they could both inhibit the activation of the Notch signaling pathway via modulating recombination signal binding protein-Jκ (RBPJ) to restore the polarization imbalance of M/M2 macrophages in EAU rats. In addition, miR-223-3p could also inhibit NLRP3 inflammasome activation and inflammasome-induced pyroptosis in ocular tissues. Taken together, our findings indicate that miR-223-3p serves as an important regulator in M1 macrophage polarization and pyroptosis, thereby alleviating the inflammatory response in uveitis.

Exploration of the shared genetic biomarkers in Alzheimer's disease and chronic kidney disease using integrated bioinformatics analysis

In order to investigate the potential link between Alzheimer's disease (AD) and chronic kidney disease (CKD), we conducted a comprehensive analysis using a bioinformatics approach. We downloaded AD and CKD datasets from the Gene Expression Omnibus database and analyzed differentially expressed genes and weighted gene co-expression networks to identify candidate genes for AD and CKD. We used a combination of the least absolute shrinkage and selection operator and random forest algorithms to select the shared genes. Subsequently, we shared genes and performed an immune infiltration analysis to investigate the association between different immune cell types and shared genes. Finally, we elucidated the relationship between the expression levels of the shared genes in disease samples and cells using single-cell analysis. Our analysis identified 150 candidate genes that may be primarily involved in immune inflammatory responses and energy metabolism pathways. We found that JunD Proto-Oncogene, ALF transcription elongation factor 1, and ZFP36 Ring Finger Protein Like 1 were the best co-diagnostic markers for AD and CKD based on the results of Least Absolute Shrinkage Selection Operator analysis and the random forest algorithm. Based on the results of immune infiltration analysis, macrophages and T-cells play a significant role in the progression of AD and CKD. Our scRNA-sequencing data showed that the 3 shared genes in AD were significantly expressed in astrocytes, excitatory neurons, oligodendrocytes, and MAIT cells. The 3 shared genes in CKD were significantly expressed in oligodendrocytes, neutrophils, fibroblasts, astrocytes, and T-cells. JunD Proto-Oncogene, ALF transcription elongation factor 1, and ZFP36 Ring Finger Protein Like 1 genes are the best diagnostic markers for AD and CKD.

PCLLA-nanoHA Bone Substitute Promotes M2 Macrophage Polarization and Improves Alveolar Bone Repair in Diabetic Environments

The utilization of bioresorbable synthetic bone substitutes with immunomodulatory properties has gained significant attention in dental clinical applications for the absorption of alveolar bone induced by orthodontic treatment. In this study, we developed two distinct materials: a conventional hydroxyapatite (HA) bone powder comprised of hydroxyapatite particles and nanoHA embedded within a poly(caprolactone-co-lactide) (PCLLA) elastomeric matrix. We assessed the physicochemical characteristics of the bone substitute, specifically focusing on its composition and the controlled release of ions. Our findings show that PCLLA-nanoHA has deformable properties under 40 N, and a significant release of Ca and P elements was noted after 7 days in aqueous settings. Moreover, at the protein and gene expression levels, PCLLA-nanoHA enhances the capacity of macrophages to polarize towards an M2 phenotype in vitro. In vivo, PCLLA-nanoHA exhibits comparable effects to standard HA bone powder in terms of promoting alveolar bone regeneration. Extensive investigations reveal that PCLLA-nanoHA surpasses the commonly employed HA bone powder in stimulating bone tissue repair in diabetic mice. We have identified that PCLLA-nanoHA regulates macrophage M2 polarization by activating the PI3K/AKT and peroxisome proliferator-activated receptor gamma (PPAR) signaling pathways, thereby facilitating a favorable local immune microenvironment conducive to bone repair and regeneration. Our findings suggest that PCLLA-nanoHA presents itself as a promising bioresorbable bone substitute with properties that promote macrophage M2 polarization, particularly in the context of regulating the local microenvironment of alveolar bone in diabetic mice, potentially facilitating bone tissue regeneration.

The Notch signaling-regulated angiogenesis in rheumatoid arthritis: pathogenic mechanisms and therapeutic potentials

Angiogenesis plays a key role in the pathological process of inflammation and invasion of the synovium, and primarily drives the progression of rheumatoid arthritis (RA). Recent studies have demonstrated that the Notch signaling may represent a new therapeutic target of RA. Although the Notch signaling has been implicated in the M1 polarization of macrophages and the differentiation of lymphocytes, little is known about its role in angiogenesis in RA. In this review, we discourse the unique roles of stromal cells and adipokines in the angiogenic progression of RA, and investigate how epigenetic regulation of the Notch signaling influences angiogenesis in RA. We also discuss the interaction of the Notch-HIF signaling in RA's angiogenesis and the potential strategies targeting the Notch signaling to improve the treatment outcomes of RA. Taken together, we further suggest new insights into future research regarding the challenges in the therapeutic strategies of RA.

Delta- like ligand 4- expressing macrophages and human diseases: Insights into pathophysiology and therapeutic opportunities

Macrophages are key players in the immune response and have been implicated in various human diseases, including atherosclerosis, cancer, and chronic inflammatory disorders. While numerous studies have delved into the nuances of macrophage behavior in these conditions, there remains a gap in understanding the specific role of Delta-like ligand 4 (Dll4)-expressing macrophages and their overarching implications across these diseases. Among the plethora of factors expressed by macrophages, Dll4 has emerged as a molecule of particular interest. Recent studies have highlighted its unique role in modulating macrophage functions and its potential implications in various diseases. This review seeks to consolidate existing knowledge, address this gap, and present a comprehensive overview of Dll4-expressing macrophages in the context of these disorders and highlight their potential as therapeutic targets. We examined the involvement of Dll4-expressing macrophages in multiple human diseases such as atherosclerosis, cancer and chronic inflammatory diseases, emphasizing their influence on disease progression. We also discussed the challenges, limitations, and emerging research areas in targeting Dll4-expressing macrophages and provide an outlook on potential therapeutic strategies for the treatment of these diseases. By addressing the previously existing research gap, we've provided a roadmap that brings together fragmented insights, paving the way for more holistic research and potentially more effective therapeutic strategies centered on Dll4-expressing macrophages.

Signaling pathways in macrophages: molecular mechanisms and therapeutic targets

Macrophages play diverse roles in development, homeostasis, and immunity. Accordingly, the dysfunction of macrophages is involved in the occurrence and progression of various diseases, such as coronavirus disease 2019 and atherosclerosis. The protective or pathogenic effect that macrophages exert in different conditions largely depends on their functional plasticity, which is regulated via signal transduction such as Janus kinase-signal transducer and activator of transcription, Wnt and Notch pathways, stimulated by environmental cues. Over the past few decades, the molecular mechanisms of signaling pathways in macrophages have been gradually elucidated, providing more alternative therapeutic targets for diseases treatment. Here, we provide an overview of the basic physiology of macrophages and expound the regulatory pathways within them. We also address the crucial role macrophages play in the pathogenesis of diseases, including autoimmune, neurodegenerative, metabolic, infectious diseases, and cancer, with a focus on advances in macrophage-targeted strategies exploring modulation of components and regulators of signaling pathways. Last, we discuss the challenges and possible solutions of macrophage-targeted therapy in clinical applications. We hope that this comprehensive review will provide directions for further research on therapeutic strategies targeting macrophage signaling pathways, which are promising to improve the efficacy of disease treatment.

GBP2 promotes M1 macrophage polarization by activating the notch1 signaling pathway in diabetic nephropathy

Background

Diabetic nephropathy (DN) is one of the most common diabetic complications, which has become the primary cause of end-stage renal disease (ESRD) globally. Macrophage infiltration has been proven vital in the occurrence and development of DN. This study was designed to investigate the hub genes involved in macrophage-mediated inflammation of DN via bioinformatics analysis and experimental validation.

Methods

Gene microarray datasets were obtained from the Gene Expression Omnibus (GEO) public website. Integrating the CIBERSORT, weighted gene co-expression network analysis (WGCNA) and DEGs, we screened macrophage M1-associated key genes with the highest intramodular connectivity. Subsequently, the Least Absolute Shrinkage and Selection Operator (LASSO) regression was utilized to further mine hub genes. GSE104954 acted as an external validation to predict the expression levels and diagnostic performance of these hub genes. The Nephroseq online platform was employed to evaluate the clinical implications of these hub genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed to elucidate the dominant biological functions and signal pathways. Finally, we conducted experiments to verify the role of GBP2 in M1 macrophage-mediated inflammatory response and the underlying mechanism of this role.

Results

Sixteen DEGs with the highest connectivity in M1 macrophages-associated module (paleturquoise module) were determined. Subsequently, we identified four hub genes through LASSO regression analysis, including CASP1, MS4A4A, CD53, and GBP2. Consistent with the training set, expression levels of these four hub genes manifested memorably elevated and the ROC curves indicated a good diagnostic accuracy with an area under the curve of greater than 0.8. Clinically, enhanced expression of these four hub genes predicted worse outcomes of DN patients. Given the known correlation between the first three hub genes and macrophage-mediated inflammation, experiments were performed to demonstrate the effect of GBP2, which proved that GBP2 contributed to M1 polarization of macrophages by activating the notch1 signaling pathway.

Conclusion

Our findings detected four hub genes, namely CASP1, MS4A4A, CD53, and GBP2, may involve in the progression of DN via pro-inflammatory M1 macrophage phenotype. GBP2 could be a promising prognostic biomarker and intervention target for DN by regulating M1 polarization.

Molecular mechanisms of COVID-19-induced pulmonary fibrosis and epithelial-mesenchymal transition

As the outbreak of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) first broke out in Hubei Province, China, at the end of 2019. It has brought great challenges and harms to global public health. SARS-CoV-2 mainly affects the lungs and is mainly manifested as pulmonary disease. However, one of the biggest crises arises from the emergence of COVID-19-induced fibrosis. At present, there are still many questions about how COVID-19 induced pulmonary fibrosis (PF) occurs and how to treat and regulate its long-term effects. In addition, as an important process of fibrosis, the effect of COVID-19 on epithelial-mesenchymal transition (EMT) may be an important factor driving PF. This review summarizes the main pathogenesis and treatment mechanisms of COVID-19 related to PF. Starting with the basic mechanisms of PF, such as EMT, transforming growth factor-β (TGF-β), fibroblasts and myofibroblasts, inflammation, macrophages, innate lymphoid cells, matrix metalloproteinases and tissue inhibitors of metalloproteinases, hedgehog pathway as well as Notch signaling. Further, we highlight the importance of COVID-19-induced EMT in the process of PF and provide an overview of the related molecular mechanisms, which will facilitate future research to propose new clinical therapeutic solutions for the treatment of COVID-19-induced PF.

Overexpression of sirtuin 1 attenuates calcium oxalate-induced kidney injury by promoting macrophage polarization

Sirtuin 1 (SIRT1) protein is involved in macrophage differentiation, while NOTCH signaling affects inflammation and macrophage polarization. Inflammation and macrophage infiltration are typical processes that accompany kidney stone formation. However, the role and mechanism of SIRT1 in renal tubular epithelial cell injury caused by calcium oxalate (CaOx) deposition and the relationship between SIRT1 and the NOTCH signaling pathway in this urological disorder are unclear. This study investigated whether SIRT1 promotes macrophage polarization to inhibit CaOx crystal deposition and reduce renal tubular epithelial cell injury. Public single-cell sequencing data, RT-qPCR, immunostaining approaches, and Western blotting showed decreased SIRT1 expression in macrophages treated with CaOx or exposed to kidney stones. Macrophages overexpressing SIRT1 differentiated towards the anti-inflammatory M2 phenotype, significantly inhibiting apoptosis and alleviating injury in the kidneys of mice with hyperoxaluria. Conversely, decreased SIRT1 expression in CaOx-treated macrophages triggered Notch signaling pathway activation, promoting macrophage polarization towards the pro-inflammatory M1 phenotype. Our results suggest that SIRT1 promotes macrophage polarization towards the M2 phenotype by repressing the NOTCH signaling pathway, which reduces CaOx crystal deposition, apoptosis, and damage in the kidney. Therefore, we propose SIRT1 as a potential target for preventing disease progression in patients with kidney stones.

Drivers of heterogeneity in synovial fibroblasts in rheumatoid arthritis

Inflammation of non-barrier immunologically quiescent tissues is associated with a massive influx of blood-borne innate and adaptive immune cells. Cues from the latter are likely to alter and expand activated states of the resident cells. However, local communications between immigrant and resident cell types in human inflammatory disease remain poorly understood. Here, we explored drivers of fibroblast-like synoviocyte (FLS) heterogeneity in inflamed joints of patients with rheumatoid arthritis using paired single-cell RNA and ATAC sequencing, multiplexed imaging and spatial transcriptomics along with in vitro modeling of cell-extrinsic factor signaling. These analyses suggest that local exposures to myeloid and T cell-derived cytokines, TNF, IFN-γ, IL-1β or lack thereof, drive four distinct FLS states some of which closely resemble fibroblast states in other disease-affected tissues including skin and colon. Our results highlight a role for concurrent, spatially distributed cytokine signaling within the inflamed synovium.

Tibetan medicine Qi-Sai-Er-Sang-Dang-Song Decoction inhibits TNF-α-induced rheumatoid arthritis in human fibroblast-like synoviocytes via regulating NOTCH1/NF-κB/NLRP3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Qi-Sai-Er-Sang-Dang-Song Decoction (QSD, ཆུ་སེར་སེང་ལྡེང་སུམ་ཐང་།), a Tibetan classical herbal formula, is commonly used in Tibetan hospital preparation for the treatment of rheumatoid arthritis (RA). Its efficacy is to relieve inflammation, dispel cold, remove dampness, and alleviate pain. However, its anti-RA mechanism is still unclear.

AIM OF THE STUDY

This study aimed to investigate the effect of QSD on rheumatoid arthritis and explore its anti-inflammatory mechanism against human fibroblast-like synoviocytes (HFLSs) by regulating the notch family of receptors (NOTCH1)/Nuclear factor-κB (NF-κB)/nucleotide-binding (NLRP3) pathway.

MATERIALS AND METHODS

We used ultra-performance liquid chromatography coupled with Q-TOF mass spectrometry (UPLC-Q-TOF-MS) to identify the chemical composition of QSD. Then, HFLSs were exposed to drug-containing serum. The effect of QSD drug-containing serum on HFLS viability was detected using the cell counting kit-8 (CCK-8) assay. Next, we explored the anti-inflammatory effect of QSD using enzyme-linked immunosorbent assay (ELISA) for inflammatory factors, such as interleukin-18 (IL-18), interleukin-1β (IL-1β), and interleukin-6 (IL-6). The expression of NOTCH-related proteins, a member of the NOTCH1, Cleaved NOTCH1, hairy and enhancer of split-1 (HES-1), NF-κB p65, NF-κB pp65, NLRP3, and delta-like 1 (DLL-1), was examined using western blotting. Furthermore, the relative mRNA expression levels of NOTCH1, NF-κB p65, NLRP3, DLL-1, and HES-1 were detected using real-time quantitative (RT-qPCR). To explore the mechanism underlying the anti-RA effect of QSD, we the used the NOTCH signaling pathway inhibitor LY411575 and transfection with a NOTCH1 siRNA. In addition, we employed immunofluorescence to determine the expression of HES-1 and NF-κB p65 in vitro.

RESULT

Our results revealed that QSD ameliorated inflammation in HFLSs. Compared with the model group, the QSD drug-containing serum group had obviously down-regulated levels of IL-18, IL-1β, and IL-6. Consistently, the CCK-8 results showed that the QSD drug-containing serum had no obvious toxicity towards HFLSs. Moreover, both LY411575 and siNOTCH1, QSD could reduce NOTCH1, NLRP3, and HES-1 protein expression levels, and LY411575 could significantly inhibit the expression levels of NF-κB p65, NF-κB pp65, and Cleaved NOTCH1 (p < 0.05). siNOTCH1 could also suppress the expression of DLL-1. The RT-qPCR results indicated that QSD could downregulate the relative mRNA expression levels of NOTCH1, NF-κB p65, NLRP3, DLL-1, and HES-1 in HFLSs (p < 0.05). In the immunofluorescence experiment, the fluorescence intensities of HES-1 and NF-κB p65 in HFLSs were found to decrease after exposure to QSD drug-containing serum (p < 0.05). Ultimately, 44 chemical components were detected in QSD using UPLC-Q-TOF-MS.

CONCLUSION

This study reveals that the QSD can markedly ameliorate inflammation induced by TNF-α on HFLS. The effect of QSD on HFLS may be exerted by inhibition of the NOTCH1/NF-κB/NLRP3 signaling pathway.

Macrophages in immunoregulation and therapeutics

Macrophages exist in various tissues, several body cavities, and around mucosal surfaces and are a vital part of the innate immune system for host defense against many pathogens and cancers. Macrophages possess binary M1/M2 macrophage polarization settings, which perform a central role in an array of immune tasks via intrinsic signal cascades and, therefore, must be precisely regulated. Many crucial questions about macrophage signaling and immune modulation are yet to be uncovered. In addition, the clinical importance of tumor-associated macrophages is becoming more widely recognized as significant progress has been made in understanding their biology. Moreover, they are an integral part of the tumor microenvironment, playing a part in the regulation of a wide variety of processes including angiogenesis, extracellular matrix transformation, cancer cell proliferation, metastasis, immunosuppression, and resistance to chemotherapeutic and checkpoint blockade immunotherapies. Herein, we discuss immune regulation in macrophage polarization and signaling, mechanical stresses and modulation, metabolic signaling pathways, mitochondrial and transcriptional, and epigenetic regulation. Furthermore, we have broadly extended the understanding of macrophages in extracellular traps and the essential roles of autophagy and aging in regulating macrophage functions. Moreover, we discussed recent advances in macrophages-mediated immune regulation of autoimmune diseases and tumorigenesis. Lastly, we discussed targeted macrophage therapy to portray prospective targets for therapeutic strategies in health and diseases.

Epsin1-mediated exosomal sorting of Dll4 modulates the tubular-macrophage crosstalk in diabetic nephropathy

Tubular epithelial cells (TECs) play critical roles in the development of diabetic nephropathy (DN), and can activate macrophages through the secretion of exosomes. However, the mechanism(s) of TEC-exosomes in macrophage activation under DN remains unknown. By mass spectrometry, 1,644 differentially expressed proteins, especially Dll4, were detected in the urine exosomes of DN patients compared with controls, which was confirmed by western blot assay. Elevated Epsin1 and Dll4/N1ICD expression was observed in kidney tissues in both DN patients and db/db mice and was positively associated with tubulointerstitial damage. Exosomes from high glucose (HG)-treated tubular cells (HK-2) with Epsin1 knockdown (KD) ameliorated macrophage activation, TNF-α, and IL-6 expression, and tubulointerstitial damage in C57BL/6 mice in vivo. In an in vitro study, enriched Dll4 was confirmed in HK-2 cells stimulated with HG, which was captured by THP-1 cells and promoted M1 macrophage activation. In addition, Epsin1 modulated the content of Dll4 in TEC-exosomes stimulated with HG. TEC-exosomes with Epsin1-KD significantly inhibited N1ICD activation and iNOS expression in THP-1 cells compared with incubation with HG alone. These findings suggested that Epsin1 could modulate tubular-macrophage crosstalk in DN by mediating exosomal sorting of Dll4 and Notch1 activation.

NOTCH signaling inhibition after DAPT treatment exacerbates alveolar echinococcosis hepatic fibrosis by blocking M1 and enhancing M2 polarization

Alveolar echinococcosis (AE) is a lethal helminthic liver disease caused by persistent infection with Echinococcus multilocularis (E. multilocularis). Although more and more attention has been paid to the macrophages in E. multilocularis infection, the mechanism of macrophage polarization, a critical player in liver immunity, is seldom studied. NOTCH signaling is involved in cell survival and macrophage-mediated inflammation, but the role of NOTCH signaling in AE has been equally elusive. In this study, liver tissue samples from AE patients were collected and an E. multilocularis infected mouse model with or without blocking NOTCH signaling was established to analyze the NOTCH signaling, fibrotic and inflammatory response of the liver after E. multilocularis infection. Changes in polarization and origin of hepatic macrophages were analyzed by flow cytometry. In vitro qRT-PCR and Western blot assays were performed to analyze key receptors and ligands in NOTCH signaling. Our data demonstrated that hepatic fibrosis develops after AE, and the overall blockade of NOTCH signaling caused by DAPT treatment exacerbates the levels of hepatic fibrosis and alters the polarization and origin of hepatic macrophages. Blocking NOTCH signaling in macrophages after E. multilocularis infection downregulates M1 and upregulates M2 expression. The downregulation of NTCH3 and DLL-3 in the NOTCH signaling pathway is significant. Therefore, NOTCH3/DLL3 may be the key pathway in NOTCH signaling regulating macrophage polarization affecting fibrosis caused by AE.

Signaling pathways in rheumatoid arthritis: implications for targeted therapy

Rheumatoid arthritis (RA) is an incurable systemic autoimmune disease. Disease progression leads to joint deformity and associated loss of function, which significantly impacts the quality of life for sufferers and adds to losses in the labor force. In the past few decades, RA has attracted increased attention from researchers, the abnormal signaling pathways in RA are a very important research field in the diagnosis and treatment of RA, which provides important evidence for understanding this complex disease and developing novel RA-linked intervention targets. The current review intends to provide a comprehensive overview of RA, including a general introduction to the disease, historical events, epidemiology, risk factors, and pathological process, highlight the primary research progress of the disease and various signaling pathways and molecular mechanisms, including genetic factors, epigenetic factors, summarize the most recent developments in identifying novel signaling pathways in RA and new inhibitors for treating RA. therapeutic interventions including approved drugs, clinical drugs, pre-clinical drugs, and cutting-edge therapeutic technologies. These developments will hopefully drive progress in new strategically targeted therapies and hope to provide novel ideas for RA treatment options in the future.

Regulation of Notch Signaling Pathway to Innate Lymphoid Cells in Patients with Acute Myocardial Infarction

The Notch signaling pathway is an important regulator in fate decisions and immune responses of innate lymphoid cells (ILCs). However, the function of Notch signaling in ILCs in acute coronary syndrome is still not fully elucidated. Thirty-one unstable angina pectoris (UAP) patients, 21 acute myocardial infarction (AMI) patients, and 20 controls were included in this study. Peripheral blood mononuclear cells (PBMCs) were isolated. The mRNA expression levels of Notch receptors and ligands were measured by real-time PCR, while ILC subsets were measured by flow cytometry. Lin^- cells were purified and stimulated with γ-secretase inhibitor (GSI). ILC subsets, transcription factors, and secreted cytokines were assessed. Notch receptor and ligand mRNA levels were elevated in PBMCs and peripheral lin^- cells from AMI patients. There was no significant difference in total lin^-CD45⁺CD161⁺CD127⁺ ILC frequency among three groups. The CRTH2^-CD117^- ILC1 subset was down-regulated, while the CRTH2⁺ ILC2 subset was up-regulated in AMI patients. The CRTH2^-CD117⁺ ILC3 subpopulation was comparable among the three groups. ILC1% was negatively correlated with Notch1 and Notch2 in AMI patients. Inhibition of Notch signaling pathway by GSI induced elevations in ILC1 frequency, T-bet mRNA expression, and interferon-γ secretion and reduced ILC2 frequency, GATA3 mRNA levels, and interleukin-5/interleukin-13 production by lin^- cells from AMI patients. The current data indicated that activation of Notch signaling pathway might contribute to ILC1-to-ILC2 shift in peripheral blood in AMI patients.

The role of Notch signaling pathway in metabolic bone diseases

Metabolic bone diseases is the third most common endocrine diseases after diabetes and thyroid diseases. More than 500 million people worldwide suffer from metabolic bone diseases. The generation and development of bone metabolic diseases is a complex process regulated by multiple signaling pathways, among which the Notch signaling pathway is one of the most important pathways. The Notch signaling pathway regulates the differentiation and function of osteoblasts and osteoclasts, and affects the process of cartilage formation, bone formation and bone resorption. Genetic mutations in upstream and downstream of Notch signaling genes can lead to a series of metabolic bone diseases, such as Alagille syndrome, Adams-Oliver syndrome and spondylocostal dysostosis. In this review, we analyzed the mechanisms of Notch ligands, Notch receptors and signaling molecules in the process of signal transduction, and summarized the progress on the pathogenesis and clinical manifestations of bone metabolic diseases caused by Notch gene mutation. We hope to draw attention to the role of the Notch signaling pathway in metabolic bone diseases and provide new ideas and approaches for the diagnosis and treatment of metabolic bone diseases.

Quantitative Proteomics Indicate Radical Removal of Non-Small Cell Lung Cancer and Predict Outcome

Non-small cell lung cancer (NSCLC) is associated with low survival rates, often due to late diagnosis and lack of personalized medicine. Diagnosing and monitoring NSCLC using blood samples has lately gained interest due to its less invasive nature. In the present study, plasma was collected at three timepoints and analyzed using proximity extension assay technology and quantitative real-time polymerase chain reaction in patients with primary NSCLC stages IA-IIIA undergoing surgery. Results were adjusted for patient demographics, tumor, node, metastasis (TNM) stage, and multiple testing. Major histocompatibility (MHC) class 1 polypeptide-related sequence A/B (MIC-A/B) and tumor necrosis factor ligand superfamily member 6 (FASLG) were significantly increased post-surgery, suggesting radical removal of cancerous cells. Levels of hepatocyte growth factor (HGF) initially increased postoperatively but were later lowered, potentially indicating radical removal of malignant cells. The levels of FASLG in patients who later died or had a relapse of NSCLC were lower at all three timepoints compared to surviving patients without relapse, indicating that FASLG may be used as a prognostic biomarker. The biomarkers were confirmed using microarray data. In conclusion, quantitative proteomics could be used for NSCLC identification but may also provide information on radical surgical removal of NSCLC and post-surgical prognosis.

Cytokine storm-calming property of the isoquinoline alkaloids in Coptis chinensis Franch

Coronavirus disease (COVID-19) has spread worldwide and its effects have been more devastating than any other infectious disease. Importantly, patients with severe COVID-19 show conspicuous increases in cytokines, including interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, IL-8, tumor necrosis factor (TNF)-α, IL-1, IL-18, and IL-17, with characteristics of the cytokine storm (CS). Although recently studied cytokine inhibitors are considered as potent and targeted approaches, once an immunological complication like CS happens, anti-viral or anti-inflammation based monotherapy alone is not enough. Interestingly, certain isoquinoline alkaloids in Coptis chinensis Franch. (CCFIAs) exerted a multitude of biological activities such as anti-inflammatory, antioxidant, antibacterial, and immunomodulatory etc, revealing a great potential for calming CS. Therefore, in this timeline review, we report and compare the effects of CCFIAs to attenuate the exacerbation of inflammatory responses by modulating signaling pathways like NF-ĸB, mitogen-activated protein kinase, JAK/STAT, and NLRP3. In addition, we also discuss the role of berberine (BBR) in two different triggers of CS, namely sepsis and viral infections, as well as its clinical applications. These evidence provide a rationale for considering CCFIAs as therapeutic agents against inflammatory CS and this suggestion requires further validation with clinical studies.

Macrophages in Renal Injury, Repair, Fibrosis Following Acute Kidney Injury and Targeted Therapy

Acute kidney injury (AKI) is a renal disease with a high incidence and mortality. Currently, there are no targeted therapeutics for preventing and treating AKI. Macrophages, important players in mammalian immune response, are involved in the multiple pathological processes of AKI. They are dynamically activated and exhibit a diverse spectrum of functional phenotypes in the kidney after AKI. Targeting the mechanisms of macrophage activation significantly improves the outcomes of AKI in preclinical studies. In this review, we summarize the role of macrophages and the underlying mechanisms of macrophage activation during kidney injury, repair, regeneration, and fibrosis and provide strategies for macrophage-targeted therapies.

Inhibition of Notch Signaling Stimulates Osteoclastogenesis From the Common Trilineage Progenitor Under Inflammatory Conditions

Osteoclasts, macrophages and dendritic cells (DCs) can be derived from a common trilineage myeloid progenitor of hematopoietic origin. Progenitor commitment is susceptible to regulation through Notch signaling. Our aim was to determine the effects of Notch modulation on trilineage progenitor commitment and functional properties of differentiated cells under inflammatory conditions. We used the conditional inducible CX3CR1CreERT2 mouse strain to achieve overexpression of the Notch 1 intracellular domain (NICD1) or to inhibit Notch signaling via deletion of the transcription factor RBP-J in a bone marrow population, used as a source of the trilineage progenitor (CD45+Ly6G−CD3−B220−NK1.1−CD11b–/loCD115+). Cre-recombinase, under the control of the CX3CR1 promoter, expressed in the monocyte/macrophage lineage, was induced in vitro by 4-hydroxytamoxifen. Differentiation of osteoclasts was induced by M-CSF/RANKL; macrophages by M-CSF; DCs by IL-4/GM-CSF, and inflammation by LPS. Functionally, DCs were tested for the ability to process and present antigen, macrophages to phagocytose E. coli particles, and osteoclasts to resorb bone and express tartrate-resistant acid phosphatase (TRAP). We found that Notch 1 signal activation suppressed osteoclast formation, whereas disruption of the Notch canonical pathway enhanced osteoclastogenesis, resulting in a higher number and size of osteoclasts. RANK protein and Ctsk gene expression were upregulated in osteoclastogenic cultures from RBP-J+ mice, with the opposing results in NICD1+ mice. Notch modulation did not affect the number of in vitro differentiated macrophages and DCs. However, RBP-J deletion stimulated Il12b and Cd86 expression in macrophages and DCs, respectively. Functional assays under inflammatory conditions confirmed that Notch silencing amplifies TRAP expression by osteoclasts, whereas the enhanced phagocytosis by macrophages was observed in both NICD1+ and RBP-J+ strains. Finally, antigen presentation by LPS-stimulated DCs was significantly downregulated with NICD1 overexpression. This experimental setting allowed us to define a cell-autonomous response to Notch signaling at the trilineage progenitor stage. Although Notch signaling modulation affected the activity of all three lineages, the major effect was observed in osteoclasts, resulting in enhanced differentiation and function with inhibition of canonical Notch signaling. Our results indicate that Notch signaling participates as the negative regulator of osteoclast activity during inflammation, which may be relevant in immune and bone diseases.

Altered expression of Notch signaling, Tlr receptors, and surfactant protein expression after prostaglandin inhibition may be associated with the delayed labor in LPS-induced mice

PURPOSE

This study aims to investigate whether indomethacin (IND) delays preterm birth by regulating the Notch pathway, Tlr receptors, and Sp-A in the placenta in lipopolysaccharide (LPS)-induced preterm labor (PTL) model.

METHODS

CD-1 mice were distributed to the pregnant control (PC), Sham, PBS, IND (2 mg/kg; i.p.), LPS (25 μg/100 μl; intrauterine), and LPS + IND groups. The injections were performed on day 14.5 of pregnancy. Placentae were collected on day 15.5 of pregnancy, and immunohistochemical analyzes were performed. Differences in staining intensities between the Cox-1, Notch-1 (N1), Dll-1, Jagged-2 (Jag-2), Tlr-2, and Tlr-4 proteins were compared.

RESULTS

Preterm labor rates were 100% and 66% (preterm delivery delayed 5 h) in the LPS and LPS + IND groups, respectively. In LPS-treated mice, a general morphological deterioration was observed in the placenta. Total placental mid-sagittal measurement was significantly reduced in the LPS-treated group, while it was similar to the PC group in the LPS + IND group. Cox-1 expression in the LZ increased, and Sp-A expression decreased after LPS injection, and IND administration diminished this increase. N1 expression increased in the labyrinth zone (LZ) and the junctional zone (JZ). Dll-1 and Jag-2 expression increased in the JZ after LPS injection (p < 0.0001). IND administration diminished Tlr-2 expression in the LZ and Tlr-4 expression in the JZ after LPS injection.

CONCLUSION

In conclusion, PG (prostaglandin) inhibition may alter Notch signaling, Tlr, and Sp-A protein expression and may be associated with delayed labor in LPS-induced mice.

Ganoderma atrum polysaccharide modulates the M1/M2 polarization of macrophages linked to the Notch signaling pathway

Macrophages could be polarized into two major sub-populations including classically activated (M1) and alternatively activated (M2) macrophages. The present study aimed to investigate the effects of Ganoderma atrum polysaccharide (PSG-1) on the regulation of macrophage polarization and further explored the associated molecular mechanisms. In this work, a lipopolysaccharide (LPS) plus IFN-γ and IL-4 were used to establish an in vitro model of two extreme states, namely pro-inflammatory M1 and anti-inflammatory M2. The results showed that PSG-1 had effects on the behavior modification of macrophage polarization by reducing CD80 expression in LPS plus IFN-γ-induced M1 macrophages, and attenuating CD23 expression in IL-4-induced M2 macrophages. Further study revealed that PSG-1-modulated M1 and M2 macrophage polarization was associated with controlling phagocytosis, reactive oxygen species generation, NO and cytokines (IL-1β, IL-6 and IL-10). Subsequently, the treatment of M1 macrophages with a combination of PSG-1 and a Notch-response inhibitor (DAPT) did not alter CD80 expression compared with DAPT alone, while several pro-inflammatory parameters were considerably decreased, suggesting that the Notch signaling pathway partly mediated the effects of PSG-1 on modulating macrophage polarization. Together, our findings suggested that PSG-1 could repair the chaos in the polarization of M1/M2 macrophages and the molecular mechanism linked to the Notch signaling pathway.

miR-223 in exosomes from bone marrow mesenchymal stem cells ameliorates rheumatoid arthritis via downregulation of NLRP3 expression in macrophages

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease with major clinical manifestations of human limb joint invasion, joint synovitis, and symmetrical lesions. In recent years, bone marrow mesenchymal stem cells (BMSCs) have been found to have low immunogenicity and immunomodulatory effects, which can regulate other types of cells through exosomes. However, the effect of BMSCs on immune response in the progression of RA has not been fully elucidated.

AIMS

The current research aimed to investigate the therapeutic effect of microRNA (miR)-223 in exosomes secreted by BMSCs on immune response in the progression of RA.

METHODS

Firstly, BMSCs were isolated and extracted, and then the influence of BMSCs on the level of inflammatory cytokines was detected by enzyme linked immunosorbent assay (ELISA). Exosomes from BMSCs were extracted and characterized. Some key autoimmune response genes and their protein products were detected in vivo and in vitro by real-time quantitative PCR, western blot and ELISA. Finally, the targeting relationship between miR-223 and NLR family pyrin domain-containing 3 (NLRP3) was predicted by bioanalytical software and verified by luciferase reporter assay and rescue experiments in vitro.

RESULTS

Exosomes from BMSCs could inhibit the release of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interleukin-18 (IL-18), and NLRP3 activation in macrophages and RA rats. In addition, we predicted online that miR-223 could target NLRP3 and provided a possible regulation pathway for the anti-inflammatory effects of BMSCs-secreted exosomes. Furthermore, we further confirmed that miR-223 could target and inhibit the expression of NLRP3.

CONCLUSION

Taken together, these findings suggest that miR-223 carried by BMSCs-derived exosomes targets NLRP3 to regulate the activation of inflammasomes, which therefore can be served as a possible therapy for RA.

Excessive Activation of Notch Signaling in Macrophages Promote Kidney Inflammation, Fibrosis, and Necroptosis

Diabetic nephropathy (DN) is one of the main causes of end-stage renal disease (ESRD). Existing treatments cannot control the progression of diabetic nephropathy very well. In diabetic nephropathy, Many monocytes and macrophages infiltrate kidney tissue. However, the role of these cells in the pathogenesis of diabetic nephropathy has not been fully elucidated. In this study, we analyzed patient kidney biopsy specimens, diabetic nephropathy model animals. Meanwhile, we cocultured cells and found that in diabetic nephropathy, damaged intrinsic renal cells (glomerular mesangial cells and renal tubular epithelial cells) recruited monocytes/macrophages to the area of tissue damage to defend against and clear cell damage. This process often involved the activation of different types of macrophages. Interestingly, the infiltrating macrophages were mainly M1 (CD68+iNOS+) macrophages. In diabetic nephropathy, crosstalk between the Notch pathway and NF-κB signaling in macrophages contributed to the polarization of macrophages. Hyperpolarized macrophages secreted large amounts of inflammatory cytokines and exacerbated the inflammatory response, extracellular matrix secretion, fibrosis, and necroptosis of intrinsic kidney cells. Additionally, macrophage depletion therapy with clodronate liposomes and inhibition of the Notch pathway in macrophages alleviated the pathological changes in kidney cells. This study provides new information regarding diabetic nephropathy-related renal inflammation, the causes of macrophage polarization, and therapeutic targets for diabetic nephropathy.

Dextran sulfate-based MMP-2 enzyme-sensitive SR-A receptor targeting nanomicelles for the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is an ordinarily occurring autoimmune disease with systemic inflammatory. Targeted drug delivery systems have many successful applications in the treatment of rheumatoid arthritis. In order to develop nanoparticles for targeted delivery of Celastrol (Cel) to rheumatoid arthritis and specific drug release, the dextran sulfate (DS) was modified as the targeting molecular by binding to the scavenger receptor of macrophage. The dextran-sulfate-PVGLIG-celastrol (DS-PVGLIG-Cel), named DPC, amphiphilic polymeric prodrug was synthesized and characterized. The resulting DPC@Cel micelles had the average size of 189.9 nm. Moreover, the micelles had ultrahigh entrapment efficiency (about 44.04%) and zeta potential of −11.91 mV. In the in vitro release study, due to the excessive production of matrix metalloproteinase-2 (MMP-2) at the inflammatory joint, the MMP-2 reactive peptide was used to crack in the inflammatory microenvironment to accelerate the release of Cel. The results have shown that the nanoparticles can effectively deliver Cel to activated macrophages and significantly improve the bioavailability. In vivo experiments showed that DPC@Cel have better anti-rheumatoid arthritis effects and lower systemic toxicity than free Cel. This study provided a new therapeutic strategy for the treatment of RA.

Nucleic Acids for Potential Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a common systemic inflammatory autoimmune disease that severely affects the life quality of patients. Current therapeutics in clinic mainly focus on alleviating the development of RA or relieving the pain of patients. The emerging biological disease-modifying antirheumatic drugs (DMARDs) require long-term treatment to achieve the expected efficacy. With the development of bionanotechnology, nucleic acids fulfill characters as therapeutics or nanocarriers and can therefore be alternatives to combat RA. This review summarizes the therapeutic RNAs developed through RNA interference (RNAi), nucleic acid aptamers, DNA nanostructures-based drug delivery systems, and nucleic acid vaccines for the applications in RA therapy and diagnosis. Furthermore, prospects of nucleic acids for RA therapy are intensively discussed as well.

Notch1 and Notch3 coordinate for pericyte-induced stabilization of vasculature

The Notch pathway regulates complex patterning events in many species and is critical for the proper formation and function of the vasculature. Despite this importance, how the various components of the Notch pathway work in concert is still not well understood. For example, NOTCH1 stabilizes homotypic endothelial junctions, but the role of NOTCH1 in heterotypic interactions is not entirely clear. NOTCH3, on the other hand, is essential for heterotypic interactions of pericytes with the endothelium, but how NOTCH3 signaling in pericytes impacts the endothelium remains elusive. Here, we use in vitro vascular models to investigate whether pericyte-induced stabilization of the vasculature requires the cooperation of NOTCH1 and NOTCH3. We observe that both pericyte NOTCH3 and endothelial NOTCH1 are required for the stabilization of the endothelium. Loss of either NOTCH3 or NOTCH1 decreases the accumulation of VE-cadherin at endothelial adherens junctions and increases the frequency of wider, more motile junctions. We found that DLL4 was the key ligand for simulating NOTCH1 activation in endothelial cells and observed that DLL4 expression in pericytes is dependent on NOTCH3. Altogether, these data suggest that an interplay between pericyte NOTCH3 and endothelial NOTCH1 is critical for pericyte-induced vascular stabilization.

Relationship of Notch Signal, Surfactant Protein A, and Indomethacin in Cervix During Preterm Birth: Mast Cell and Jagged-2 May Be Key in Understanding Infection-mediated Preterm Birth

Although it is thought that there is a close relationship between Notch signal and preterm birth, the functioning of this mechanism in the cervix is unknown. The efficacy of surfactants and prostaglandin inhibitors in preterm labor is also still unclear. In this study, 48 female CD-1 mice were distributed to pregnant control (PC), Sham, PBS, indomethacin (2 mg/kg; intraperitoneally), lipopolysaccharides (LPS) (25 μg/100 μl; intrauterine), LPS + IND, and Surfactant Protein A Block (SP-A Block: SP-A B; the anti-SP-A antibody was applied 20 µg/100μl; intrauterine) groups. Tissues were examined by immunohistochemistry, immunofluorescence, and Western blot analysis. LPS administration increased the expression of N1 Dll-1 and Jagged-2 (Jag-2). Although Toll-like receptor (Tlr)-2 significantly increased in the LPS-treated and SP-A-blocked groups, Tlr-4 significantly increased only in the LPS-exposed groups. It was observed that Jag-2 is specifically expressed by mast cells. Overall, this experimental model shows that some protein responses increase throughout the uterus, starting at a specific point on the cervix epithelium. Surfactant Protein A, which we observed to be significantly reduced by LPS, may be associated with the regulation of the epithelial response, especially during preterm delivery due to infection. On the contrary, prostaglandin inhibitors can be considered an option to delay infection-related preterm labor with their dose-dependent effects. Finally, the link between mast cells and Jag-2 could potentially be a control switch for preterm birth.

Transcriptomic and Lipidomic Mapping of Macrophages in the Hub of Chronic Beta-Adrenergic-Stimulation Unravels Hypertrophy-, Proliferation-, and Lipid Metabolism-Related Genes as Novel Potential Markers of Early Hypertrophy or Heart Failure

Sympathetic nervous system overdrive with chronic release of catecholamines is the most important neurohormonal mechanism activated to maintain cardiac output in response to heart stress. Beta-adrenergic signaling behaves first as a compensatory pathway improving cardiac contractility and maladaptive remodeling but becomes dysfunctional leading to pathological hypertrophy and heart failure (HF). Cardiac remodeling is a complex inflammatory syndrome where macrophages play a determinant role. This study aimed at characterizing the temporal transcriptomic evolution of cardiac macrophages in mice subjected to beta-adrenergic-stimulation using RNA sequencing. Owing to a comprehensive bibliographic analysis and complementary lipidomic experiments, this study deciphers typical gene profiles in early compensated hypertrophy (ECH) versus late dilated remodeling related to HF. We uncover cardiac hypertrophy- and proliferation-related transcription programs typical of ECH or HF macrophages and identify lipid metabolism-associated and Na⁺ or K⁺ channel-related genes as markers of ECH and HF macrophages, respectively. In addition, our results substantiate the key time-dependent role of inflammatory, metabolic, and functional gene regulation in macrophages during beta-adrenergic dependent remodeling. This study provides important and novel knowledge to better understand the prevalent key role of resident macrophages in response to chronically activated beta-adrenergic signaling, an effective diagnostic and therapeutic target in failing hearts.

MOSES: A New Approach to Integrate Interactome Topology and Functional Features for Disease Gene Prediction

Disease gene prediction is to date one of the main computational challenges of precision medicine. It is still uncertain if disease genes have unique functional properties that distinguish them from other non-disease genes or, from a network perspective, if they are located randomly in the interactome or show specific patterns in the network topology. In this study, we propose a new method for disease gene prediction based on the use of biological knowledge-bases (gene-disease associations, genes functional annotations, etc.) and interactome network topology. The proposed algorithm called MOSES is based on the definition of two somewhat opposing sets of genes both disease-specific from different perspectives: warm seeds (i.e., disease genes obtained from databases) and cold seeds (genes far from the disease genes on the interactome and not involved in their biological functions). The application of MOSES to a set of 40 diseases showed that the suggested putative disease genes are significantly enriched in their reference disease. Reassuringly, known and predicted disease genes together, tend to form a connected network module on the human interactome, mitigating the scattered distribution of disease genes which is probably due to both the paucity of disease-gene associations and the incompleteness of the interactome.

The Notch signaling pathway regulates macrophage polarization in liver diseases

The liver is not only the main metabolic site of exogenous compounds and drugs, but also an important immune organ in the human body. When a large number of nonself substances (such as drugs, alcohol, pathogens, microorganisms and their metabolites) enter the liver, they will cause serious liver diseases, including liver fibrosis, liver cirrhosis, liver failure, and hepatocellular carcinoma (HCC). Macrophages are the first line of defense against the invasion of exogenous pathogens and significant cellular components of the innate immune system. Macrophages have strong heterogeneity and plasticity. When different pathogens invade the body, they cause different types of polarization of macrophages through different molecular mechanisms. Notch signaling is considered to be the key regulator of the biological function of macrophages. Activating Notch signaling can regulate the differentiation of macrophages into M1 and play a role in promoting inflammation and antitumor activity, while blocking Notch signaling can polarize macrophages to M2, suppressing inflammation and promoting tumor growth. However, there are few studies on regulation of macrophage polarization by the Notch signaling pathway in liver diseases. Therefore, in this review, we will introduce the role of the Notch signaling pathway in regulating macrophage polarization in liver diseases.

Notch Signaling Ligand Jagged1 Enhances Macrophage-Mediated Response to Helicobacter pylori

Helicobacter pylori (H. pylori) is one of the gram-negative bacteria that mainly colonize the stomach mucosa and cause many gastrointestinal diseases, such as gastritis, peptic ulcer, and gastric cancer. Macrophages play a key role in eradicating H. pylori. Recent data have shown that Notch signaling could modulate the activation and bactericidal activities of macrophages. However, the role of Notch signaling in macrophages against H. pylori remains unclear. In the present study, in the co-culture model of macrophages with H. pylori, the inhibition of Notch signaling using γ-secretase decreased the expression of inducible nitric oxide synthase (iNOS) and its product, nitric oxide (NO), and downregulated the secretion of pro-inflammatory cytokine and attenuated phagocytosis and bactericidal activities of macrophages to H. pylori. Furthermore, we identified that Jagged1, one of Notch signaling ligands, was both upregulated in mRNA and protein level in activated macrophages induced by H. pylori. Clinical specimens showed that the number of Jagged1⁺ macrophages in the stomach mucosa from H. pylori-infected patients was significantly higher than that in healthy control. The overexpression of Jagged1 promoted bactericidal activities of macrophages against H. pylori and siRNA-Jagged1 presented the opposite effect. Besides, the addition of exogenous rJagged1 facilitated the pro-inflammatory mediators of macrophages against H. pylori, but the treatment of anti-Jagged1 neutralizing antibody attenuated it. Taken together, these results suggest that Jagged1 is a promoting molecule for macrophages against H. pylori, which will provide insight for exploring Jagged1 as a novel therapeutic target for the control of H. pylori infection.

Macrophage Related Chronic Inflammation in Non-Healing Wounds

Persistent hyper-inflammation is a distinguishing pathophysiological characteristic of chronic wounds, and macrophage malfunction is considered as a major contributor thereof. In this review, we describe the origin and heterogeneity of macrophages during wound healing, and compare macrophage function in healing and non-healing wounds. We consider extrinsic and intrinsic factors driving wound macrophage dysregulation, and review systemic and topical therapeutic approaches for the restoration of macrophage response. Multidimensional analysis is highlighted through the integration of various high-throughput technologies, used to assess the diversity and activation states as well as cellular communication of macrophages in healing and non-healing wound. This research fills the gaps in current literature and provides the promising therapeutic interventions for chronic wounds.

The Notch Pathway: A Link Between COVID-19 Pathophysiology and Its Cardiovascular Complications

COVID-19 is associated with a large number of cardiovascular sequelae, including dysrhythmias, myocardial injury, myocarditis and thrombosis. The Notch pathway is one likely culprit leading to these complications due to its direct role in viral entry, inflammation and coagulation processes, all shown to be key parts of COVID-19 pathogenesis. This review highlights links between the pathophysiology of SARS-CoV2 and the Notch signaling pathway that serve as primary drivers of the cardiovascular complications seen in COVID-19 patients.