Protective and pathogenic functions of macrophage subsets

Glial polarization in neurological diseases: Molecular mechanisms and therapeutic opportunities

Glial cell polarization plays a pivotal role in various neurological disorders. In response to distinct stimuli, glial cells undergo polarization to either mitigate neurotoxicity or facilitate neural repair following injury, underscoring the importance of glial phenotypic polarization in modulating central nervous system function. This review presents an overview of glial cell polarization, focusing on astrocytes and microglia. It explores the involvement of glial polarization in neurological diseases such as Alzheimer's disease, Parkinson's disease, stroke, epilepsy, traumatic brain injury, amyotrophic lateral sclerosis, multiple sclerosis and meningoencephalitis. Specifically, it emphasizes the role of glial cell polarization in disease pathogenesis through mechanisms including neuroinflammation, neurodegeneration, calcium signaling dysregulation, synaptic dysfunction and immune response. Additionally, it summarizes various therapeutic strategies including pharmacological treatments, dietary supplements and cell-based therapies, aimed at modulating glial cell polarization to ameliorate brain dysfunction. Future research focused on the spatio-temporal manipulation of glial polarization holds promise for advancing precision diagnosis and treatment of neurological diseases.

Peripheral monocyte subsets are altered during gestation in oocyte donation pregnancy complicated with pre-eclampsia

Oocyte donation (OD) pregnancies show a higher fetal-maternal incompatibility and a higher risk of developing pre-eclampsia (PE) than autologous pregnancies. As maternal monocytes play a role in the tolerization of the allogeneic fetus, the aim of this study was to analyse monocyte phenotypes in healthy and PE OD pregnancies. We collected maternal peripheral blood at different gestational time points in healthy (n = 10) and PE (n = 5) OD pregnancies. Fetal-maternal human leukocyte antigen (HLA) mismatches were calculated. We used a 35-colour antibody panel for Aurora spectral flow cytometry to analyse the composition and surface marker expression of monocyte subsets. Expression of CD38 on intermediate monocytes significantly increased throughout gestation in healthy OD pregnancies. Compared with the healthy group, the PE group exhibited even higher CD38 expression on monocyte subsets, with statistical significance. Immune inhibiting receptors CD85j (LILRB1) and CD85d (LILRB2), as well as monocyte recruitment regulating molecules CCR2 and CD91, also showed significantly enhanced expression on monocyte subsets during PE. When comparing healthy and PE OD only in pregnancies with high HLA mismatches, the different CD38 and CD85j expression in monocyte subsets was still significant. In conclusion, in healthy OD pregnancies, the upregulated CD38 expression might reflect a proinflammatory condition specifically at the third trimester. In PE OD pregnancies, expression of both inflammatory and immune regulatory markers is increased in maternal peripheral monocyte subsets. The elevated expression of CCR2 and CD91 on these subsets might reflect monocyte chemotaxis and the effect from systemic vascular dysfunction at the late stage of PE.

Multifunctional biosynthesized magnetosome for multimodal imaging and combined therapy of tumor

The large recruitment of tumor-associated macrophages and low exposure of tumor-associated antigens in tumor microenvironment have severely suppress the efficacy of anti-tumor immunotherapy. Herein, biosynthesized magnetosome (Mag) from bacteria was loaded with photothermal/photodynamic agent/near infrared (NIR) fluorescence dye (IR780) and further modified with lipid-PEG-c(RGDyK) through biomembrane, forming IMagRGD for fluorescence imaging, magnetic resonance imaging, immunotherapy and photodynamic/photothermal therapy. After intravenous injection into B16F10 tumor-bearing mice, IMagRGD could efficiently accumulate in tumor tissues based on near infrared (NIR) fluorescence and magnetic resonance dual-modality imaging, and repolarize tumor-associated macrophages (TAMs) from M2 phenotype to M1 phenotype, significantly improving the effect of tumor immunotherapy. Moreover, photothermal and photodynamic effect of IR780 could kill tumor cells and elicit immunogenic cell death to mediate anti-tumor immunity, promoting dendritic cells (DCs) maturation and then activating specific effector T cells to further eliminate tumor cells. This study provides a new approach for reversing the activity of tumor immunosuppressive microenvironment and strengthening the efficiency of tumor photoimmunotherapy.

Analysis of Immunological Biomarkers Associated With Rejection After Uterus Transplantation in Human

BACKGROUND

Uterus transplantation (UTx) is an emerging therapy for women with uterine infertility. However, critical questions remain with this procedure including the mechanisms involved in graft rejection.

METHODS

In this study, we analyzed the immune profile of ectocervical biopsies from 5 patients after UTx before and during their first episode of rejection using RNA sequencing, quantitative polymerase chain reaction, and imaging mass cytometry.

RESULTS

We identified 530 upregulated and 207 downregulated genes associated with graft rejection. Enrichment databases revealed abnormalities of skin-associated genes and the immune system, in particular activation of T and B lymphocytes, and macrophages. Imaging mass cytometry confirmed these observations; in cervical biopsies of 3 women, rejection was associated with the presence of B-cell structures linked to tertiary lymphoid structures, and 2 biopsies from 1 woman with severe rejection episodes and poor prognosis of graft function (repeated miscarriage and implantation failures) were associated with an accumulation of HLA-DR - macrophages, producing granzyme B at the surface of the epithelium.

CONCLUSIONS

We showed that rejection of a UTx graft was associated with major alterations of immune markers including the involvement of tertiary lymphoid structures, the most organized of which may be a sign of chronic rejection, and with an increase in HLA-DR - macrophages expressing granzyme B in the case of grade 3 rejection episodes according Mölne's classification. We identified potential emerging biomarkers to predict or diagnose graft rejection (Keratin 1 granzyme B, IL1β). These findings could lead to development of improved strategies for the identification, prevention, and/or treatment of uterus graft rejection.

The ETS domain-containing hematopoietic transcription factor PU.1 mediates the induction of arachidonate 5-lipoxygenase by multi-walled carbon nanotubes in macrophages in vitro

Exposure to fibrogenic multi-walled carbon nanotubes (MWCNTs) induces the production of proinflammatory lipid mediators (LMs) in myeloid cells to instigate inflammation. The molecular underpinnings of LM production in nanotoxicity remain unclear. Here we report that PU.1, an ETS domain-containing master regulator of hematopoiesis, critically regulates the induction of arachidonate 5-lypoxygenase (Alox5) and the production of LMs. MWCNTs (Mitsui-7) at 2.5 or 10 µg/mL induced the expression of Alox5 in murine and human macrophages at both mRNA and protein levels, accompanied by marked elevation of chemotactic LM leukotriene B4 (LTB4). Induction is comparable to those by potent M1 inducers. Carbon black, an amorphous carbon material control, did not increase Alox5 expression or LTB4 production at equivalent doses. MWCNTs induced the expression of a heterologous luciferase reporter under the control of the murine Alox5 promoter. Deletional analysis of the 2 kb promoter uncovered multiple inhibitory and activating activities. The proximal 250 bp region had the largest activation that was further increased by MWCNTs. The Alox5 promoter contains four PU box-like enhancers. PU.1 bond to each of the enhancers constitutively, which was further increased by MWCNTs. Knockdown of PU.1 using specific small hairpin-RNA blocked the basal and induced expression of Alox5 and the production of LTB4 as well as prostaglandin E2. The results demonstrate a critical role of PU.1 in mediating MWCNTs-induced expression of Alox5 and production of proinflammatory LMs, revealing a molecular framework where the hematopoietic transcription factor PU.1 is activated to orchestrate multiple proinflammatory responses to sterile particulates.

Noncoding RNAs in sepsis-associated acute liver injury: Roles, mechanisms, and therapeutic applications

Sepsis is a life-threatening syndrome characterized by organ dysfunction caused by a dysregulated host response to infection. Sepsis-associated acute liver injury (SA-ALI) is a frequent and serious complication of sepsis that considerably impacts both short-term and long-term survival outcomes. In intensive care units (ICUs), the mortality rate of patients with SA-ALI remains high, mostly due to the absence of effective early diagnostic markers and suitable therapeutic strategies. Recent studies have demonstrated the importance of non-coding RNAs (ncRNAs) in the development and progression of SA-ALI. This review focuses on the critical roles of ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), in regulating "cytokine storms", oxidative stress, mitochondrial dysfunction, and programmed cell death in SA-ALI, and summarizes the current state and limitations of existing studies on lncRNAs and circRNAs in SA-ALI. By integrating advancements in high-throughput sequencing technologies, this review provides novel insights into the dual potential of ncRNAs as diagnostic biomarkers and therapeutic targets, offers new ideas for SA-ALI diagnosis and treatment research and highlights potential challenges in clinical translation.

Ferroptosis contributes to immunosuppression

As a novel form of cell death, ferroptosis is mainly regulated by the accumulation of soluble iron ions in the cytoplasm and the production of lipid peroxides and is closely associated with several diseases, including acute kidney injury, ischemic reperfusion injury, neurodegenerative diseases, and cancer. The term "immunosuppression" refers to various factors that can directly harm immune cells' structure and function and affect the synthesis, release, and biological activity of immune molecules, leading to the insufficient response of the immune system to antigen production, failure to successfully resist the invasion of foreign pathogens, and even organ damage and metabolic disorders. An immunosuppressive phase commonly occurs in the progression of many ferroptosis-related diseases, and ferroptosis can directly inhibit immune cell function. However, the relationship between ferroptosis and immunosuppression has not yet been published due to their complicated interactions in various diseases. Therefore, this review deeply discusses the contribution of ferroptosis to immunosuppression in specific cases. In addition to offering new therapeutic targets for ferroptosis-related diseases, the findings will help clarify the issues on how ferroptosis contributes to immunosuppression.

The Immunomodulatory Activity of High Doses of Vitamin D in Critical Care Patients with Severe SARS-CoV-2 Pneumonia-A Randomized Controlled Trial

Vitamin D receptor [VDR] expression promotes LL37 expression, possibly contributing to host defense. The hypothesis was that an increase in 25 hydroxyvitamin D [25vitD] could lead to enhanced VDR expression and increased LL-37 production, thereby contributing to improved prognosis in critically ill patients. Methods: A nonblinded, randomized controlled trial was conducted. A total of 207 patients admitted to ICU with severe SARS-CoV-2 pneumonia were included and received different doses of cholecalciferol (500 MU, 3 MU/day, no cholecalciferol) during their ICU and hospital stay. 25vitD levels as well as LL37 and monocytes' VDR gene expression were evaluated on admission and after. Clinical evolution, ICU mortality, hospital mortality, and 60-day mortality were evaluated. Results: The median age was 57.7 years and the majority of patients were Caucasian [87.4%] and male [70.5%]. There was a significant difference in 25vitD levels between groups on the third [p = 0.002] and seventh [p < 0.001] days. Patients supplemented with 500 MU of cholecalciferol had a very significant increase in monocytes' VDR gene expression and showed a better clinical evolution in the ICU, with a significant correlation to evolution factors. Higher LL37 on admission had a significant negative association with hospital and ICU mortality, lost after adjustment for comorbidities to a nearly significant association with ICU, hospital, and 60-day mortality. Conclusion: Supplementation with higher doses of cholecalciferol may contribute to a significant increase in 25vitD levels but not in LL37 levels. Higher LL37 levels on admission may be related to a decrease in ICU, hospital, and 60-day mortality. VDR gene expression in monocytes is much higher in patients supplemented with higher doses of cholecalciferol.

Origin, Function, and Implications of Intestinal and Hepatic Macrophages in the Pathogenesis of Alcohol-Associated Liver Disease

Macrophages are members of the human innate immune system, and the majority reside in the liver. In recent years, they have been recognized as essential players in the maintenance of liver and intestinal homeostasis as well as key guardians of their respective immune systems, and they are increasingly being recognized as such. Paradoxically, they are also likely involved in chronic pathologies of the gastrointestinal tract and potentially in the alteration of the gut-liver axis in alcohol use disorder (AUD) and alcohol-associated liver disease (ALD). To date, the causal relationship between macrophages, the pathogenesis of ALD, and the immune dysregulation of the gut remains unclear. In this review, we will discuss our current understanding of the heterogeneity of intestinal and hepatic macrophages, their ontogeny, the potential factors that regulate their origin, and the evidence of how they are associated with the manifestation of chronic inflammation. We will also illustrate how the micro-environment of the intestine shapes the phenotypes and functionality of the macrophage compartment in both the intestines and liver and how they change during chronic alcohol abuse. Finally, we highlight the obstacles to current research and the prospects for this field.

Anatomical, subset, and HIV-dependent expression of viral sensors and restriction factors

We developed viral sensor and restriction factor-cytometry by time of flight (VISOR-CyTOF), which profiles 19 viral sensors and restriction factors (VISORs) simultaneously in single cells, and applied it to 41 postmortem tissues from people with HIV. Mucosal myeloid cells are well equipped with SAMHD1 and sensors of viral capsid and DNA while CD4+ T cells are not. In lymph node CD4+ Tfh, VISOR expression patterns reflect those favoring integration but blocking HIV gene expression, thus favoring viral latency. We also identify small subsets of bone marrow-, lung-, and gut-associated CD4+ T and myeloid cells expressing high levels of restriction factors targeting most stages of the HIV replication cycle. In vitro, HIV preferentially fuses to CD4+ T cells with a permissive VISOR profile, but early induction of select VISORs by T1IFN prevents productive HIV infection. Our findings document the diverse patterns of VISOR profiles across tissues and cellular subsets and define their association with susceptibility to HIV.

Efferocytosis: A new star of atherosclerotic plaques reversal

Efferocytosis is considered the key to eliminate apoptotic cells (ACs) under physiological and pathological conditions in vivo, mainly through different types of macrophages to achieve this process. Especially, tissue-resident macrophages (TRMs) are very significant for inflammation regression and maintenance of homeostasis in vivo. Abnormal efferocytosis will lead to the accumulation of ACs and the release of a variety of pro-inflammatory factors, which mediates the occurrence of many inflammatory diseases, including atherosclerosis (AS). AS is a chronic inflammatory vascular disease with the participation of the immune system. Defective efferocytosis will accelerate the progress of AS to a certain extent. Therefore, it is of great significance to understand the mechanism of efferocytosis and realize the prevention and treatment of AS through efferocytosis. In this review, we will briefly describe the specific process of efferocytosis, deeply discuss the possible molecular mechanism of impaired efferocytosis promoting the development of AS, and summarize the ways to prevent and treat AS through efferocytosis intervention therapy.

Antigen B from Echinococcus granulosus regulates macrophage phagocytosis by controlling TLR4 endocytosis in immune thrombocytopenia

Immune thrombocytopenia (ITP) is characterized by a reduction in platelet counts, stemming from an autoimmune-mediated process where platelets are excessively cleared by macrophages. This enhanced phagocytosis is a cardinal pathogenic mechanism in ITP. Antigen B (AgB), a principal component of the Echinococcus granulosus cyst fluid, plays a pivotal role in safeguarding the parasite from host immune defenses by modulating macrophage activation. In this study, we explored the potential of AgB to regulate macrophage activation in the context of ITP. Our observations indicated a diminished presence of M1 macrophages and a reduced phagocytic capacity in patients infected with E. granulosus sensu stricto. We isolated AgB from E. granulosus cyst fluid (EgCF) and discovered that it could suppress the polarization of M1 macrophages and weaken their phagocytic activity via Fcγ receptors, consequently alleviating thrombocytopenia in an ITP mouse model. At the molecular level, AgB was found to suppress the activation of nuclear factor kappa B (NF-κB) and interferon regulatory factor 3 (IRF3) by impeding their nuclear translocation, leading to a reduction in the generation of inflammatory cytokines. Furthermore, AgB was shown to inhibit Toll-like receptor 4 (TLR4) endocytosis and the recycling of CD14. In aggregate, our findings uncover a novel immunomodulatory mechanism of AgB, which suppresses macrophage phagocytosis by regulating TLR4 endocytosis and the subsequent activation of NF-κB and IRF3 signaling pathways. These insights shed new light on the molecular intricacies of E. granulosus-induced immune evasion and suggest that AgB may serve as a promising therapeutic agent for ITP.

Cryopreserved human alternatively activated macrophages promote resolution of acetaminophen-induced liver injury in mouse

Acute liver failure is a rapidly progressing, life-threatening condition most commonly caused by an overdose of acetaminophen (paracetamol). The antidote, N-acetylcysteine (NAC), has limited efficacy when liver injury is established. If acute liver damage is severe, liver failure can rapidly develop with associated high mortality rates. We have previously demonstrated that alternatively, activated macrophages are a potential therapeutic option to reverse acute liver injury in pre-clinical models. In this paper, we present data using cryopreserved human alternatively activated macrophages (hAAMs)-which represent a potential, rapidly available treatment suitable for use in the acute setting. In a mouse model of APAP-induced injury, peripherally injected cryopreserved hAAMs reduced liver necrosis, modulated inflammatory responses, and enhanced liver regeneration. hAAMs were effective even when administered after the therapeutic window for NAC. This cell therapy approach represents a potential treatment for APAP overdose when NAC is ineffective because liver injury is established.

The Role of the Tumor Microenvironment in T-Cell Redirecting Therapies of Large B-Cell Lymphoma: Lessons Learned from CAR-T to Bispecific Antibodies

T-cell redirecting therapies, which include chimeric antigen receptor T-cells (CAR-Ts) and bispecific antibodies (BSAs), have revolutionized the treatment of relapsed\refractory large B-cell lymphoma (LBCL). Expanding clinical experience with these advanced therapies shows the potential for the optimization of their use with combination or consolidation strategies, which necessitates the prognostic stratification of patients. While traditional clinical prognostic factors identified in the era of chemotherapy are characterized by limited value, the tumor microenvironment (TME) is becoming a new prognostic cluster. We examine how the heterogeneity of LBCL, characterized by variations in tumor parameters and differences in TME immune cell composition, immune checkpoint expression, and cytokine milieu, correlates with both positive responses and resistance to treatment. While classical parameters such as histological subtype, cell of origin, and target antigen expression lack proven prognostic value for T-cell redirecting therapies, the density and functional state of tumor-infiltrating lymphocytes, tumor-associated macrophages, and immune checkpoint molecules are shown to be critical determinants of therapeutic success, particularly in CAR-T therapy. We identify several gaps in the current knowledge and suggest that the insights gained from CAR-T experience could be instrumental in refining BSA applications. This report also highlights limitations in the current knowledge, as TME data derive from a limited number of registrational trials with varying methodologies, complicating cross-study comparisons and often focusing on immediate response metrics rather than long-term outcomes. By dissecting the complex interactions within the TME, this review aims to identify new prognostic factors and targets, ultimately fostering more effective and tailored treatment strategies for LBCL patients.

Differential pathological changes in colon microenvironments in acute and chronic mouse models of inflammatory bowel disease

Inflammatory bowel disease is a chronic condition characterized by inflammation of the gastrointestinal tract, resulting from an abnormal immune response to normal stimuli, such as food and intestinal flora. Since the etiology of this disease remains largely unknown, murine models induced by the consumption of dextran-sodium sulfate serve as a pivotal tool for studying colon inflammation. In this study, we employed both acute and chronic colitis mouse models induced by varying durations of dextran-sodium sulfate consumption to investigate the pathological and immunologic characteristics throughout the disease course. During the acute phase, activated innate inflammation marked by M1 macrophage infiltration was prominent. In contrast, the chronic phase was characterized by tissue remodeling, with a significant increase in M2 macrophages and lymphocytes. RNA-sequencing revealed genetic changes in acute and chronic colitis, marked by the maintenance of genomic integrity in the acute phase and extracellular matrix dynamics in the chronic phase. These phase-specific alterations reflect the multifaceted physiological processes involved in the initiation and progression of inflammation in the large intestine, underscoring the necessity for distinct experimental approaches for each phase. The findings demonstrate that the factors shaping the large intestinal immune microenvironment change specifically during the acute and chronic phases of experimental inflammatory bowel disease, highlighting the importance of developing therapeutic strategies that align with the disease course.

Role of macrophage polarization in diabetic foot ulcer healing: A bibliometric study

BACKGROUND

Diabetic foot ulcers (DFUs) are a significant contributor to disability and mortality in diabetic patients. Macrophage polarization and functional regulation are promising areas of research and show therapeutic potential in the field of DFU healing. However, the complex mechanism, the difficulty in clinical translation, and the large heterogeneity present significant challenges. Hence, this study was to comprehensively analyze the publication status and trends of studies on macrophage polarization and DFU healing.

AIM

To examine the relevant literature on macrophage polarization in DFU healing.

METHODS

A bibliometric analysis was conducted using the Web of Science database. Relevant literature was retrieved from the Web of Science Core Collection database between 2013 to 2023 using literature visualization and analysis software (VOSviewer and CiteSpace) and bibliometric online platforms. The obtained literature was then subjected to visualization and analysis of different countries/regions, institutions, journals, authors, and keywords to reveal the research's major trends and focus.

RESULTS

The number of publications on the role of macrophage polarization in DFU healing increased rapidly from 2013 to 2023, especially in the latter period. Chinese researchers were the most prolific in this field, with 217 publications, while American researchers had been engaged in this field for a longer period. Qian Tan of Nanjing Drum Tower Hospital and Qian Ding of Nanjing University were the first to publish in this field. Shanghai Jiao Tong University was the institution with the most publications (27). The keywords "bone marrow", "adjustment, replacement, response, tissue repair", and "activation, repair, differentiation" appeared more frequently. The study of macrophage polarization in DFU healing focused on the regulatory mechanism, gene expression, and other aspects.

CONCLUSION

This study through the bibliometric method reveals the research trends and development trends in this field of macrophage polarization in DFU healing from 2013 to 2023 in the Web of Science Core Collection database. The key hotspots in this field mainly include the regulation of macrophage activation, gene expression, wound tissue repair, and new wound materials. This study provides references for future research directions.

Synthetic Vesicle-Based Drug Delivery Systems for Oral Disease Therapy: Current Applications and Future Directions

Oral diseases such as dental caries, periodontitis, and oral cancer are prevalent and present significant challenges to global public health. Although these diseases are typically treated through procedures like dental preparation and resin filling, scaling and root planning, or surgical excision, these interventions are often not entirely effective, and postoperative drug therapy is usually required. Traditional drug treatments, however, are limited by factors such as poor drug penetration, significant side effects, and the development of drug resistance. As a result, there is a growing need for novel drug delivery systems that can enhance therapeutic efficacy, reduce side effects, and improve treatment outcomes. In recent years, drug-loaded vesicles, such as liposomes, polymersomes, and extracellular vesicles (EVs), have emerged as promising drug delivery platforms due to their high drug encapsulation efficiency, controlled release properties, and excellent biocompatibility. This review provides an in-depth examination of the characteristics, advantages, and limitations of liposomes, polymersomes, and extracellular vesicles in the context of oral disease treatment. It further explores the reasons for their advantages and limitations and discusses the specific applications, development prospects, and strategies for optimizing these vesicle-based systems for improved clinical outcomes.

The role of M1/M2 macrophage polarization in the pathogenesis of obesity-related kidney disease and related pathologies

Obesity is a rapidly growing health problem worldwide, affecting both adults and children and increasing the risk of chronic diseases such as type 2 diabetes, hypertension and cardiovascular disease (CVD). In addition, obesity is closely linked to chronic kidney disease (CKD) by either exacerbating diabetic complications or directly causing kidney damage. Obesity-related CKD is characterized by proteinuria, lipid accumulation, fibrosis and glomerulosclerosis, which can gradually impair kidney function. Among the immune cells of the innate and adaptive immune response involved in the pathogenesis of obesity-related diseases, macrophages play a crucial role in the inflammation associated with CKD. In obese individuals, macrophages enter a pro-inflammatory state known as M1 polarization, which contributes to chronic inflammation. This polarization promotes tissue damage, inflammation and fibrosis, leading to progressive loss of kidney function. In addition, macrophage-induced oxidative stress is a key feature of CKD as it also promotes cell damage and inflammation. Macrophages also contribute to insulin resistance in type 2 diabetes by releasing inflammatory molecules that impair glucose metabolism, complicating the management of diabetes in obese patients. Hypertension and atherosclerosis, which are often associated with obesity, also contribute to the progression of CKD via immune and inflammatory pathways. Macrophages influence blood pressure regulation and contribute to vascular inflammation, particularly via the renin-angiotensin system. In atherosclerosis, macrophages accumulate in arterial plaques, leading to chronic inflammation and plaque instability, which may increase the risk of CVD in CKD patients. This review focuses on the involvement of macrophages in CKD and highlights their role as a critical link between CKD and other pathologies. Targeting macrophage polarization and the ensuing macrophage-induced inflammation could be an effective therapeutic strategy for CKD and related diseases and improve outcomes for patients with obesity-related kidney disease.

ANGPTL4 induces Kupffer cell M2 polarization to mitigate acute rejection in liver transplantation

Acute rejection (AR) is a significant complication in liver transplantation, impacting graft function and patient survival. Kupffer cells (KCs), liver-specific macrophages, can polarize into pro-inflammatory M1 or anti-inflammatory M2 phenotypes, both of which critically influence AR outcomes. Angiopoietin-like 4 (ANGPTL4), a secretory protein, is recognized for its function in regulating inflammation and macrophage polarization. This study investigates the effects of ANGPTL4 on KC polarization through cellular interactions between hepatocytes (HCs) and KCs. Using a rat orthotopic liver transplantation model, we observed reduced ANGPTL4 expression during AR, whereas increased ANGPTL4 levels were linked to immune tolerance. Administration of ANGPTL4 recombinant protein improved liver function, suppressed inflammation, and promoted M2 polarization of KCs. Co-culture experiments demonstrated that hepatocyte-derived ANGPTL4 significantly modulates KC polarization and inflammatory responses, mainly by inhibiting the NF-κB signaling pathway. The results emphasize the promise of ANGPTL4 as a therapeutic target to reduce AR and improve liver transplant outcomes by influencing hepatocyte-KC interactions.

Treatment with sitagliptin exacerbates the M2 phenotype in macrophages in vitro

Macrophages (MØ) participate in the induction and the control of the host's immune response in homeostasis and during inflammatory diseases. Sitagliptin is a drug that inhibits the enzyme dipeptidyl peptidase 4 (DPP-4) and, therefore, increases the bioavailability of the incretins GIP (Gastric inhibitory polypeptide) and GLP-1 (Glucagon-like polypeptide). Thus, sitagliptin has been used to treat obesity and type II diabetes and has recently been associated with anti-inflammatory effects. It is known that the drug can modulate the immune response, however, the underlying mechanisms are not yet completely elucidated, including how they interfere with the activation and function of MØ. Here, we aimed to investigate and characterize the effects of in vitro treatment with sitagliptin on MØ polarization. Bone marrow-derived MØ were differentiated with conditioned medium from the L929 cell line. For M1, MØ were stimulated with IFN-γ and LPS, and for M2, with IL-4 and IL-13 for 24 h. Sitagliptin treatment was performed during MØ polarization. Polarized MØ were assessed for M1/M2 markers, DPP-4, GLP-1 and GIP receptors, mitochondrial dynamics and phagocytosis. Sitagliptin treatment exacerbates the M2 phenotype, featured by increased expression of CD206 and ARG1 and decreased gene expression levels of TNF-α. Sitagliptin-treated M2 altered mitochondrial dynamics with reduced membrane potential and mitochondrial reactive oxygen species production. These differences were accompanied by low gene expression levels of genes related to mitofusion, suggesting that sitagliptin treatment interferes with mitochondria function in M2, and exhibited less phagocytic capacity. In summary, our data suggest that sitagliptin exacerbates M2 profile in vitro.

Piezo1 Enhances Macrophage Phagocytosis and Pyrin Activation to Ameliorate Fungal Keratitis

Purpose

Fungal keratitis (FK) remains a treatment challenge, necessitating new therapeutic targets. Piezo1, a mechanosensitive ion channel, regulates calcium signaling and immune cell function. This study investigates its role in macrophage-mediated antifungal responses in FK.

Methods

Piezo1 and Pyrin expression in corneas and bone marrow-derived macrophages (BMDMs) were assessed by RNAseq, quantitative real-time PCR (qRT-PCR), Western blot, and immunofluorescence. Intracellular calcium ion concentration was detected by Fluo-4 AM fluorescent probe staining. Heterozygous Piezo1 deficiency (Piezo1+/-) mice and Yoda1 were performed to regulate the expression of Piezo1.

Results

Our investigation demonstrates elevated expression of Piezo1 in the corneas of patients with FK and infected mice. This upregulation of Piezo1 corresponded with the swift recruitment of macrophages via the limbus. Additionally, Piezo1+/- mice exacerbate the progression of FK in the infection model. Furthermore, Piezo1 knockdown in macrophages exhibit a notable reduction phagocytic capacity, accompanied by an increase in viable colony-forming units in an in vitro model of fungal infection. Moreover, using a pharmacologic activator of Piezo1 (Yoda1), a calcium ion (Ca2+) chelator of BAPTA or Piezo1+/- mice, we demonstrate that Piezo1 activation triggers the Pyrin inflammasome via augmented calcium ion influx, which is required for protection against FK in murine hosts.

Conclusions

Piezo1 is crucial for innate immunity in FK, enhancing macrophage recruitment, activation, and Pyrin inflammasome-mediated antifungal activity via calcium signaling. Using Piezo1+/- mice and Yoda1, we confirm Piezo1's role in fungal clearance. Targeting Piezo1 offers a novel strategy to improve FK outcomes by boosting macrophage function and immune response.

USP25 stabilizes STAT6 to promote IL-4-induced macrophage M2 polarization and fibrosis

As a leading cause of morbidity and mortality, fibrosis is the common pathway of various chronic inflammatory diseases in organs and causes death in a large number of patients. It can destroy the structure and function of organs and ultimately lead to organ failure, which is a major cause of disability and death in many diseases. However, the regulatory mechanism of organ fibrosis is not well clear and the lack of effective drugs and treatments, which seriously endangers human health and safety. In this study, we found that ubiquitin specific peptidases 25 (USP25) deficiency could protect mice from bleomycin (BLM)-induced pulmonary fibrosis and bile duct ligation (BDL)-induced liver fibrosis. Mechanistically, USP25 deficiency reduced the infiltration of M2 macrophages in the lungs and livers. USP25 inhibits signal transducer and activator of transcription 6 / peroxisome proliferator-activated receptor gamma (STAT6/PPAR-γ) signaling by reducing the K48 specific ubiquitination of STAT6, thereby promoting IL-4-induced M2 macrophages. Overall, our findings support that USP25 promotes the development of fibrosis by facilitating macrophage M2 polarization.

Progress in Designing Therapeutic Antimicrobial Hydrogels Targeting Implant-associated Infections: Paving the Way for a Sustainable Platform Applied to Biomedical Devices

Implantable biomedical devices have found widespread use in restoring lost functions or structures within the human body, but they face a significant challenge from microbial-related infections, which often lead to implant failure. In this context, antimicrobial hydrogels emerge as a promising strategy for treating implant-associated infections owing to their tunable physicochemical properties. However, the literature lacks a comprehensive analysis of antimicrobial hydrogels, encompassing their development, mechanisms, and effect on implant-associated infections, mainly in light of existing in vitro, in vivo, and clinical evidence. Thus, this review addresses the strategies employed by existing studies to tailor hydrogel properties to meet the specific needs of each application. Furthermore, this comprehensive review critically appraises the development of antimicrobial hydrogels, with a particular focus on solving infections related to metallic orthopedic or dental implants. Then, preclinical and clinical studies centering on providing quantitative microbiological results associated with the application of antimicrobial hydrogels are systematically summarized. Overall, antimicrobial hydrogels benefit from the tunable properties of polymers and hold promise as an effective strategy for the local treatment of implant-associated infections. However, future clinical investigations, grounded on robust evidence from in vitro and preclinical studies, are required to explore and validate new antimicrobial hydrogels for clinical use.

Topography immune-responsive silk films for skin regeneration

Scar formation and chronic refractory wounds pose a significant threat to public health, with abnormal immune regulation as a key characteristic. However, topography, a crucial factor influencing immune responses, has not been adequately considered in the design of wound dressings. In this study, we constructed a hierarchical structure on silk fibroin (SF) films by combining soft lithography and femtosecond laser ablation, without altering the intrinsic properties of SF. The discontinuity in the hierarchical structure induced a transformation in the morphology of macrophage RAW264.7 cells from round to spindle or pancake-like shapes, leading to phenotypic polarization toward M2 or M1. The timely transition from M1 to M2 polarization and the balance between these states promoted fibroblast L929 cells to express mRNA for FN, coll-I, TGF-β1, and α-SMA. The hierarchical structure of SF films facilitates full-thickness wound repair in vivo by regulating inflammation and promoting neovascularization and collagen deposition. Thus, hierarchical topography presents a promising strategy for the design of immunomodulatory wound dressings.

Guanylate binding protein1 alters expression of the poly I: C induced cytokines/chemokines and MAP kinases in macrophages

Guanylate binding protein 1 (GBP1) is critical in the host's innate immune response against viral infections and inflammation. Therefore, this study explored the role of GBP1 poly I: C, a synthetic analog of double-stranded RNA that mimics viral infections-induced inflammation in macrophages. Stimulation of human macrophage THP-1 and mice macrophage RAW 264.7 cell lines with 1 μg/ml of poly I: C revealed differential expression patterns of GBP1 to GBP7. Further, to know the specific role of GBP1in poly I: C induced inflammation, GBP1 gene was silenced in these two macrophage cells using small interfering RNA (siRNA), leading to significant reductions in GBP1 mRNA and protein levels. Further, the expression of key cytokines (IFN-γ, TNF-α, IL-4, IL-10, and IL-12b) and chemokines (CXCL9, CXCL10, CXCL11) after poly I: C treatment resulted in altered cytokine and chemokine expression profiles. Additionally, increased phosphorylation of ERK1/2, p38, and STAT1 transcription factors was observed in GBP1 knockdown cells. No change in the expression level of c-Jun and NF-kB was observed in response to poly I: C in GBP1 silenced cells compared to control cells. These findings provide valuable insights into the crosstalk/connection of GBP1 in poly I: C-induced immune responses in macrophages.

Innovative Hydrogel Design: Tailoring Immunomodulation for Optimal Chronic Wound Recovery

Despite significant progress in tissue engineering, the full regeneration of chronic wounds persists as a major challenge, with the immune response to tissue damage being a key determinant of the healing process's quality and duration. Post-injury, a crucial aspect is the transition of macrophages from a pro-inflammatory state to an anti-inflammatory. Thus, this alteration in macrophage polarization presents an enticing avenue within the realm of regenerative medicine. Recent advancements have entailed the integration of a myriad of cellular and molecular signals into hydrogel-based constructs, enabling the fine-tuning of immune cell activities during different phases. This discussion explores modern insights into immune cell roles in skin regeneration, underscoring the key role of immune modulation in amplifying the overall efficacy of wounds. Moreover, a comprehensive review is presented on the latest sophisticated technologies employed in the design of immunomodulatory hydrogels to regulate macrophage polarization. Furthermore, the deliberate design of hydrogels to deliver targeted immune stimulation through manipulation of chemistry and cell integration is also emphasized. Moreover, an overview is provided regarding the influence of hydrogel properties on immune traits and tissue regeneration process. Conclusively, the accent is on forthcoming pathways directed toward modulating immune responses in the milieu of chronic healing.

Primary sensory neuron-derived miR-let-7b underlies stress-elicited psoriasis

Psoriasis, a chronic autoimmune skin condition with significant global morbidity, badly impairs patients' quality of life. Stress has been identified as a prominent trigger for psoriasis, and effectively management of stress can ameliorate its pathological manifestations. However, the precise mechanisms by which stress influences psoriasis remain elusive. In this study, we found that mice subjected to chronic social defeat stress (CSDS) exhibit severer imiquimod (IMQ)-induced psoriasis with increased epidermal scaling, epidermal hyperplasia, number of epidermal ridges, itch, and skin inflammation than control mice. Mechanistic study reveals that CSDS leads to an elevated release of miR-let-7b, an endogenous ligand of Toll-like receptor 7 (TLR7), from the peripheral terminal of dorsal root ganglia (DRG) neurons into the skin. This process can stimulate skin-resident macrophages to release cytokines (such as IL-6 and TNF-a) and chemokines (such as MCP-1), subsequently promoting the recruitment of additional macrophages into the skin. Notably, the specific blockade of miR-let-7b in DRG neurons effectively relieve stress-induced exacerbations of psoriasis. Furthermore, intradermal injection of synthetic miR-let-7b can induce a psoriasis-like phenotype in wildtype mice, a phenomenon that can be countered by the application of a TLR7 antagonist. Additionally, microfluidic chamber coculture assays demonstrated that miR-let-7b released by DRG neurons activates macrophages via TLR7 expressed on these immune cells. Totally, this study found that stress-induced upregulation and release of miR-let-7b from DRG neurons stimulates macrophages to secrete more inflammatory cytokines and chemokines, thereby exacerbating skin inflammation and the psoriatic phenotype. These findings provide a potential therapeutic strategy targeting the miR-let-7b/TLR7 pathway to alleviate stress-induced exacerbation of psoriasis.

Differential effects of macrophage subtype-specific cytokines on fibroblast proliferation and endothelial cell function in co-culture system

Macrophages are involved in several critical activities associated with tissue repair and regeneration. Current approaches in regenerative medicine are focusing on leveraging the innate immune response to accelerate tissue regeneration and improve long-term healing outcomes. Of particular interest in this regard are the currently known, four main M2 macrophage subtypes: M2interleukin (IL)-4,IL-13, M2IC, M2IL-10, M2non-selective adenosine receptor agonists (NECA) (M2IL-4,IL-13 → M2NECA). In this study, rat bone marrow-derived macrophages (M0) were polarized to each of the four subtypes M2IL-4,IL-13 → M2NECA and cultured for 72 h in vitro. Luminex assay results highlighted increased production of tissue inhibitor of metalloproteinases-1 (TIMP-1) for M2IL-4,IL-13, higher amounts of transforming growth factor-beta 1 (TGF-β1) for M2IL-10, and elevated vascular endothelial growth factor A (VEGF-A) from M2NECA. Co-culture experiments performed with M2IL-10 macrophages and L929 fibroblasts highlighted the increased production of soluble collagen within the media as well as higher amounts of collagen in the extracellular matrix. Human umbilical vein endothelial cells (HUVECs) were co-cultured with M2NECA macrophages, which demonstrated an increase in intercellular adhesion molecule (ICAM) and platelet endothelial cell adhesion molecule (PECAM), as well as increased formation of endothelial tubes. The findings of this study emphasize a critical demand for further characterization and analyses of distinct M2 subtypes and careful selection of specific macrophage populations for regeneration of specific tissue types. The current, broad classification of "M2" may be sufficient in many general tissue engineering applications, but, as conditions are constantly in flux within the microenvironment in vivo, a higher degree of specificity and control over the initial M2 subtype could result in more consistent long-term outcomes where macrophages are utilized as part of an overall regenerative strategy.

The Kaposi sarcoma herpesvirus control of monocytes, macrophages, and the tumour microenvironment

Kaposi sarcoma herpesvirus (KSHV) is an oncogenic DNA virus associated with various malignancies, including tumours like Kaposi sarcoma and Primary effusion lymphoma. Recently, the importance of the tumour microenvironment in KSHV-associated tumours is being studied. New studies utilizing human primary cells, co-culture experiments with KSHV-infected cells, and modern techniques like time-resolved single cell analysis, have significantly advanced the understanding of KSHV interactions with monocytes and macrophages. These cells play key roles in shaping the tumour microenvironment. It has become clear that KSHV-infected endothelial cells regulate the growth and the differentiation of monocytes and macrophages. Monocytes and macrophages, in turn, can regulate KSHV-infected cells in tumorigenesis and cytokine secretion, leading to the pro-tumour microenvironment. Further investigations into the viral regulation of monocytes and macrophages thus have potential to lead to the discovery of novel antitumour therapeutics.

The neurorepellent SLIT2 inhibits LPS-induced proinflammatory signaling in macrophages

Macrophages are important mediators of immune responses with critical roles in the recognition and clearance of pathogens, as well as in the resolution of inflammation and wound healing. The neuronal guidance cue SLIT2 has been widely studied for its effects on immune cell functions, most notably directional cell migration. Recently, SLIT2 has been shown to directly enhance bacterial killing by macrophages, but the effects of SLIT2 on inflammatory activation of macrophages are less known. Using RNA sequencing analysis, quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay, we determined that in murine bone marrow-derived macrophages challenged with the potent proinflammatory mediator lipopolysaccharide (LPS), exposure to the bioactive N-terminal fragment of SLIT2 (NSLIT2) suppressed production of proinflammatory cytokines interleukin (IL)-6 and IL-12 and concurrently increased the anti-inflammatory cytokine IL-10. We found that NSLIT2 inhibited LPS-induced MyD88- and TRIF-mediated signaling cascades and did not inhibit LPS-induced internalization of Toll-like receptor 4 (TLR4), but instead inhibited LPS-induced upregulation of macropinocytosis. Inhibition of macropinocytosis in macrophages attenuated LPS-induced production of proinflammatory IL-6 and IL-12 and concurrently enhanced anti-inflammatory IL-10. Taken together, our results indicate that SLIT2 can selectively modulate macrophage response to potent proinflammatory stimuli, such as LPS, by attenuating proinflammatory activation and simultaneously enhancing anti-inflammatory activity. Our results highlight the role of macropinocytosis in proinflammatory activation of macrophages exposed to LPS. Given that LPS-producing bacteria cause host illness through synergistic direct bacterial infection and excessive LPS-induced systemic inflammation, our work suggests a novel therapeutic role for SLIT2 in combatting the significant morbidity and mortality of patients with Gram-negative bacterial sepsis.

Immune Cells and Intracerebral Hemorrhage: A Causal Investigation Through Mendelian Randomization

BACKGROUND

The involvement of immune cells in the pathophysiology of intracerebral hemorrhage (ICH) is becoming increasingly recognized, yet their specific causal contributions remain uncertain. The objective of this research is to uncover the potential causal interactions between diverse immune cells and ICH using Mendelian randomization (MR) analysis.

METHODS

Genetic variants associated with 731 immune cell traits were sourced from a comprehensive genome-wide association study (GWAS) involving 3757 participants. Summary statistics data for ICH were acquired from FinnGen, comprising 4056 ICH cases and 371,717 controls. The principal analytical tool utilized in our study was the inverse-variance weighted (IVW) method, incorporated as a key component of a two-sample MR approach. To mitigate potential biases and verify the stability of the conclusions drawn from the primary analytical methods, a series of sensitivity analyses were performed.

RESULTS

MR analysis elucidated 33 immune cell traits with causal associations, comprising B cells (eight traits), conventional dendritic cells (cDC, two traits), maturation stages of T cells (two traits), monocytes (two traits), myeloid cells (five traits), TBNK cells (six traits), and regulatory T cells (Treg, eight traits). DP (CD4+CD8+) %T cell (OR = 0.83, CI = 0.72-0.96, p = 0.013) exhibited the strongest protective effect. In contrast, transitional AC (OR = 1.09, CI = 1.02-1.16, p = 0.006) and IgD- CD27- %lymphocyte (OR = 1.08, CI = 1.00-1.17, p = 0.045) showed a higher tendency to increase the ICH risk. The sensitivity analyses validated the robustness and consistency of these results.

CONCLUSION

Our research provides robust evidence substantiating the causal relationship between specific immunophenotypes and ICH risk. The identification of these findings significantly enhances our understanding of the pathogenic mechanisms underlying ICH, particularly pertaining to the immune system. This breakthrough paves the way for innovative clinical and pharmaceutical research opportunities, potentially promoting the development of targeted therapies and enhanced strategies for managing and preventing ICH.

A data-driven approach to establishing cell motility patterns as predictors of macrophage subtypes and their relation to cell morphology

The motility of macrophages in response to microenvironment stimuli is a hallmark of innate immunity, where macrophages play pro-inflammatory or pro-reparatory roles depending on their activation status during wound healing. Cell size and shape have been informative in defining macrophage subtypes. Studies show pro and anti-inflammatory macrophages exhibit distinct migratory behaviors, in vitro, in 3D and in vivo but this link has not been rigorously studied. We apply both morphology and motility-based image processing approaches to analyze live cell images consisting of macrophage phenotypes. Macrophage subtypes are differentiated from primary murine bone marrow derived macrophages using a potent lipopolysaccharide (LPS) or cytokine interleukin-4 (IL-4). We show that morphology is tightly linked to motility, which leads to our hypothesis that motility analysis could be used alone or in conjunction with morphological features for improved prediction of macrophage subtypes. We train a support vector machine (SVM) classifier to predict macrophage subtypes based on morphology alone, motility alone, and both morphology and motility combined. We show that motility has comparable predictive capabilities as morphology. However, using both measures can enhance predictive capabilities. While motility and morphological features can be individually ambiguous identifiers, together they provide significantly improved prediction accuracies (75%) from a training dataset of 1000 cells tracked over time using only phase contrast time-lapse microscopy. Thus, the approach combining cell motility and cell morphology information can lead to methods that accurately assess functionally diverse macrophage phenotypes quickly and efficiently. This can support the development of cost efficient and high through-put methods for screening biochemicals targeting macrophage polarization.

Imperative role of adaptor proteins in macrophage toll-like receptor signaling pathways

Macrophages are integral part of the body's defense against pathogens and serve as vital regulators of inflammation. Adaptor molecules, featuring diverse domains, intricately orchestrate the recruitment and transmission of inflammatory responses through signaling cascades. Key domains involved in macrophage polarization include Toll-like receptors (TLRs), Src Homology2 (SH2) and other small domains, alongside receptor tyrosine kinases, crucial for pathway activation. This review aims to elucidate the enigmatic role of macrophage adaptor molecules in modulating macrophage activation, emphasizing their diverse roles and potential therapeutic and investigative avenues for further exploration.

Iron Oxide Nanoparticle-Based T1 Contrast Agents for Magnetic Resonance Imaging: A Review

This review highlights recent progress in utilizing iron oxide nanoparticles (IONPs) as a safer alternative to gadolinium-based contrast agents (GBCAs) for magnetic resonance imaging (MRI). It consolidates findings from multiple studies, discussing current T1 contrast agents (CAs), the synthesis techniques for IONPs, the theoretical principles for designing IONP-based MRI CAs, and the key factors that impact their T1 contrast efficacy, such as nanoparticle size, morphology, surface modifications, valence states, and oxygen vacancies. Furthermore, we summarize current strategies to achieve IONP-based responsive CAs, including self-assembly/disassembly and distance adjustment. This review also evaluates the biocompatibility, organ accumulation, and clearance pathways of IONPs for clinical applications. Finally, the challenges associated with the clinical translation of IONP-based T1 CAs are included.

Ruscogenin attenuates osteoarthritis by modulating oxidative stress-mediated macrophage reprogramming via directly targeting Sirt3

BACKGROUND

Synovial inflammation, Cartilage erosion, and subchondral osteosclerosis, which are collectively referred to as the triad of pathogenesis, contribute to osteoarthritis (OA) progression. Specifically, the M1 macrophage in the synovium worsens the development of the illness and is a significant factor in the deterioration and functioning of cartilage.

OBJECTIVE

To investigate whether Ruscogenin attenuates progressive degeneration of articular cartilage in rats with anterior cruciate ligament transection (ACLT)-induced osteoarthritis (OA) by modulating macrophage reprogramming and to explore its specific mechanism of action.

METHODS

In vitro, SW1353 cells and RAW264.7 cells were applied to elucidate the mechanisms by which Ruscogenin protects articular cartilage. Specifically, the expression levels of molecules related to cartilage ECM synthesis and degradation enzymes and macrophages were analysed. In vivo, a rat osteoarthritis model was established using ACLT. The protective effect of Ruscogenin on articular cartilage was observed.

RESULTS

Ruscogenin significantly reversed LPS-induced macrophage inflammatory response and promoted cartilage regeneration-related factors. In addition, Ruscogenin had a significant protective effect on the knee joint of ACLT rats, effectively preventing cartilage degeneration. These positive therapeutic effects were achieved on the one hand by Ruscogenin regulating macrophage reprogramming by targeting Sirt3, and on the other hand Ruscogenin could attenuate the ROS level of chondrocytes thereby inhibiting chondrocyte ferroptosis.

CONCLUSIONS

Ruscogenin exerts chondroprotective effects by regulating macrophage reprogramming and inhibiting chondrocyte ferroptosis.

Reprogramming tumor-associated macrophages with lipid nanosystems reduces PDAC tumor burden and liver metastasis

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) requires innovative therapeutic strategies to counteract its progression and metastatic potential. Since the majority of patients are diagnosed with advanced metastatic disease, treatment strategies targeting not only the primary tumor but also metastatic lesions are needed. Tumor-Associated Macrophages (TAMs) have emerged as central players, significantly influencing PDAC progression and metastasis. Our objective was to validate an innovative therapeutic strategy involving the reprogramming of TAMs using lipid nanosystems to prevent the formation of a pro-metastatic microenvironment in the liver.

RESULTS

In vitro results demonstrate that M2-polarized macrophages lose their M2-phenotype following treatment with lipid nanoemulsions composed of vitamin E and sphingomyelin (VitE:SM), transitioning to an M0/M1 state. Specifically, VitE:SM nanoemulsion treatment decreased the expression of macrophage M2 markers such as Arg1 and Egr2, while M1 markers such as Cd86, Il-1b and Il-12b increased. Additionally, the TGF-βR1 inhibitor Galunisertib (LY2157299) was loaded into VitE:SM nanoemulsions and delivered to C57BL/6 mice orthotopically injected with KPC PDAC tumor cells. Treated mice showed diminished primary tumor growth and reduced TAM infiltration in the liver. Moreover, we observed a decrease in liver metastasis with the nanoemulsion treatment in an intrasplenic model of PDAC liver metastasis. Finally, we validated the translatability of our VitE:SM nanosystem therapy in a human cell-based 3D co-culture model in vivo, underscoring the pivotal role of macrophages in the nanosystem's therapeutic effect in the context of human PDAC metastasis.

CONCLUSIONS

The demonstrated effectiveness and safety of our nanosystem therapy highlights a promising therapeutic approach for PDAC, showcasing its potential in reprogramming TAMs and mitigating the occurrence of liver metastasis.

The Emerging Role of Schwann Cells in the Tumor Immune Microenvironment and Its Potential Clinical Application

As the primary glial cells in the peripheral nervous system (PNS), Schwann cells (SCs) have been proven to influence the behavior of cancer cells profoundly and are involved in cancer progression through extensive interactions with cancer cells and other stromal cells. Indeed, the tumor microenvironment (TME) is a critical factor that can significantly limit the efficacy of immunotherapeutic approaches. The TME promotes tumor progression in part by reshaping an immunosuppressive state. The immunosuppressive TME is the result of the crosstalk between the tumor cells and the different immune cell subsets, including macrophages, natural killer (NK) cells, dendritic cells (DCs), lymphocytes, myeloid-derived suppressor cells (MDSCs), etc. They are closely related to the anti-tumor immune status and the clinical prognosis of cancer patients. Increasing research demonstrates that SCs influence these immune cells and reshape the formation of the immunosuppressive TME via the secretion of various cytokines, chemokines, and other effector molecules, eventually facilitating immune evasion and tumor progression. In this review, we summarize the SC reprogramming in TME, the emerging role of SCs in tumor immune microenvironment, and the underlying mechanisms involved. We also discuss the possible therapeutic strategies to selectively target SCs, providing insights and perspectives for future research and clinical studies involving SC-targeted treatment.

Vascular Smooth Muscle Cells Transdifferentiate into Chondrocyte-Like Cells and Facilitate Meniscal Fibrocartilage Regeneration

The effective and translational strategy to regenerate knee meniscal fibrocartilage remained challenging. Herein, we first identified vascular smooth muscle cells (VSMCs) transdifferentiated into fibrochondrocytes and participated in spontaneous meniscal regeneration using smooth muscle cell lineage tracing transgenic mice meniscal defect model. Then, we identified low-intensity pulsed ultrasound (LIPUS) acoustic stimulus enhanced fibrochondrogenic transdifferentiation of VSMCs in vitro and in vivo. Mechanistically, LIPUS stimulus could up-regulate mechanosensitive ion channel Piezo1 expression and then activate the transforming growth factor β1 (TGFβ1) signal, following repression of the Notch signal, consequently enhancing fibrochondrogenic transdifferentiation of VSMCs. Finally, we demonstrated that the regular LIPUS stimulus enhanced anisotropic native-like meniscal fibrocartilage tissue regeneration in a beagle canine subtotal meniscectomy model at 6 months postoperatively. The single-cell RNA sequencing analysis confirmed the role of VSMC fibrochondrogenic transdifferentiation in meniscal regeneration.

Nanotherapeutics for Macrophage Network Modulation in Tumor Microenvironments: Targets and Tools

Macrophage is an important component in the tumor immune microenvironment, which exerts significant influence on tumor development and metastasis. Due to their dual nature of promoting and suppressing inflammation, macrophages can serve as both targets for tumor immunotherapy and tools for treating malignancies. However, the abundant infiltration of tumor-associated macrophages dominated by an immunosuppressive phenotype maintains a pro-tumor microenvironment, and engineering macrophages using nanotechnology to manipulate the tumor immune microenvironment represent a feasible approach for cancer immunotherapy. Additionally, considering the phagocytic and specifically tumor-targeting capabilities of M1 macrophages, macrophages manipulated through cellular engineering and nanotechnology, as well as macrophage-derived exosomes and macrophage membranes, can also become effective tools for cancer treatment. In conclusion, nanotherapeutics targeting macrophages remains immense potential for the development of macrophage-mediated tumor treatment methods and will further enhance our understanding, diagnosis, and treatment of various malignants.

Inhibition of fibulin-3 ameliorates periodontal inflammation through reducing M1 macrophage polarization via EGFR/PI3K/AKT pathway

BACKGROUND

This study aimed to evaluate the role of fibulin-3 (FBLN3) in macrophage polarization, its mechanism, and its effect on periodontitis.

METHODS

We conducted studies on periodontitis using both clinical samples and ligature-induced mouse periodontitis model. The inflammatory state was assessed using microcomputed tomography, hematoxylin and eosin staining, immunohistochemical staining, and immunofluorescence staining. In vitro, bone marrow-derived macrophages, and RAW 264.7 macrophages were treated with lipopolysaccharide (LPS) and interleukin (IL)-4 to induce polarization. The role of FBLN3 in macrophage polarization was investigated using overexpression plasmids or siRNAs. Furthermore, local injection of adeno-associated virus was employed to suppress FBLN3 expression in periodontal tissues.

RESULTS

FBLN3 levels were greater in periodontitis tissues. FBLN3 promoted M1 polarization and suppressed M2 polarization in macrophages. The overexpression of FBLN3 promoted M1 polarization via the EGFR/PI3K/AKT signaling pathway, an effect that the epidermal growth factor receptor (EGFR) inhibitor PD153035 reversed. Suppressing FBLN3 expression improved periodontal inflammation and reduced alveolar bone loss in periodontitis.

CONCLUSIONS

FBLN3 suppression can mitigate periodontitis by decreasing the M1 macrophage ratio. FBLN3 regulates M1 macrophage polarization through the EGFR/PI3K/AKT signaling pathway.

PLAIN LANGUAGE SUMMARY

Disruption in the collaboration between extracellular matrix (ECM) and immune system is a significant pathology in periodontitis. Macrophages are a crucial part of the immune system and have unique functions, such as polarization. Fibulin-3, an ECM protein, may play a vital role in this dynamic interplay. Fibulin-3 expression is elevated in periodontitis and is closely related to immune cell function. Inhibiting fibulin-3 can alleviate periodontitis by reducing infiltration of immune cells and M1 macrophage ratio. Furthermore, fibulin-3 promoted macrophage M1 polarization by activating the PI3K/AKT signaling pathway through EGFR binding. Our findings offer a clinically relevant rationale for immune response modulation through fibulin-3.

Nanosensor quantitative monitoring of ROS/RNS homeostasis in single phagolysosomes of macrophages during bactericidal processes

Reactive oxygen and nitrogen species (ROS/RNS) in macrophages have a potent killing effect on pathogens that infect the host. Here, we achieved in situ, quantitative detection of the homeostasis of four primary ROS/RNS (ONOO-, H2O2, NO, and NO2-) and their precursors (O2˙-, NO) in phagolysosomes of single RAW 264.7 macrophages after phagocytosis of Escherichia coli with platinum-black nanoelectrodes. Enhanced bactericidal activity of the macrophages was observed by an increase in the total amount of ROS/RNS as well as the level and proportion of ONOO-, a potent bactericidal species of RNS. Moreover, both the bactericidal process and the steady-state replenishment process were dominated by the production of RNS (NO-based), revealing differences in the enzyme kinetics of the bactericidal process.

Stressor-Actuated Proximity Labeling for Reporting Cellular Interaction

Cell-cell interactions determine the activation state and function of cells. When host cells are exposed to stressors such as microorganisms, immune defense machinery is activated to release H2O2, providing direct evidence of the relevant cellular physiological processes. Inspired by the fact that peroxidase can catalyze proximity labeling in the presence of exogenous H2O2, a stressor-actuated proximity labeling (SAPL) strategy is developed to report the process information on cell-cell interactions by recording stress levels. The stressors are covalently modified with horseradish peroxidase (HRP) and the H2O2 released by the host cells in response to the stressors triggers HRP-based proximity labeling. Using a fungal mimic or live fungi as stressors, the stress levels of different host cells are compared by in situ imaging of the labeling signals. The ability to accumulate stress signals allows SAPL to more sensitively differentiate between interactions involving different macrophage phenotypes. SAPL is also a powerful tool for real-time, in situ monitoring of the effects of surface modifications on cellular interactions. Thus, the SAPL strategy represents a new perspective in the monitoring of cell-cell interactions using endogenous effector molecules.

Szabo B, Kothalawala RC, Szekelyhidi V, Nagy P, Varga Z, Panyi G, Zakany F. Inhibition of the HV1 voltage-gated proton channel compromises the viability of human polarized macrophages in a polarization- and ceramide-dependent manner

The human voltage-gated proton channel (HV1) provides an efficient proton extrusion pathway from the cytoplasm contributing to the intracellular pH regulation and the oxidative burst. Although its pharmacological inhibition was previously shown to induce cell death in various cell types, no such effects have been examined in polarized macrophages albeit HV1 was suggested to play important roles in these cells. This study highlights that 5-chloro-2-guanidinobenzimidazole (ClGBI), the most widely applied HV1 inhibitor, reduces the viability of human THP-1-derived polarized macrophages at biologically relevant doses with M1 macrophages being the most, and M2 cells the least sensitive to this compound. ClGBI may exert this effect principally by blocking HV1 since the sensitivity of polarized macrophages correlates well with their HV1 expression levels; inhibitors of other macrophage ion channels that may be susceptible for off-target ClGBI effects cause no viability reductions; and Zn2+, another non-specific HV1 blocker, exerts similar effects. As a potential mechanism behind the ClGBI-induced cell death, we identify a complex pH dysregulation involving acidification of the cytoplasm and alkalinization of the lysosomes, which eventually result in membrane ceramide accumulation. Furthermore, ClGBI effects are alleviated by ARC39, a selective acid sphingomyelinase inhibitor supporting the unequivocal significance of ceramide accumulation in the process. Altogether, our results suggest that HV1 inhibition leads to cellular toxicity in polarized macrophages in a polarization-dependent manner, which occurs due to a pH dysregulation and concomitant ceramide overproduction mainly depending on the activity of acid sphingomyelinase. The reduced macrophage viability and plausible concomitant changes in homeostatic M1-M2 balance could contribute to both the therapeutic and potential side effects of HV1 inhibitors that show great promise in the treatment of neuroinflammation and malignant diseases.

Protective effect of xylosma congesta extract on renal injury in hyperuricemic rats

Background

The purpose of this study was to investigate the protective effect of xylosma congesta extract on kidney injury in hyperuricemic rats.

Methods

The rats were fed yeast extract and intraperitoneal injections of potassium oxonate for 3 weeks to establish the hyperuricemia model. And then the rats were treated with allopurinol and different doses of oak extract. The contents of uric acid in urine and serum, creatinine, and urea nitrogen in serum were detected by biochemical methods. TUNEL was used to detect cell apoptosis in renal tissue. The protein expression of TLR4 and NF- kappa B (NF-κB) p65 and the proportion of CD68 and CD206 positive cells in renal tissue were detected by pathological method.

Results

The xylosma congesta group showed decreased renal tubular dilatation, decreased renal interstitial inflammatory cell infiltration, decreased serum creatinine content, and decreased apoptotic cell count as compared to the model group. And positive expression of TLR4 and NF-κB decreased with each dose. Additionally, the xylosma congesta groups showed a significant rise in CD206 and a considerable decrease in CD68.

Conclusion

The extract from xylosma congesta has the ability to lower serum uric acid and creatinine levels while also providing protection against kidney damage caused by hyperuricemia.

Renal cell carcinoma and macrophage research: A bibliometric analysis (2004-2023)

To analyze hotspots and trends in renal cell carcinoma (RCC)-macrophage research using bibliometric analysis, although numerous studies on macrophages in RCC have been recently reported, understanding the progressive trends in this field remains challenging. Publications focused on macrophages in RCC were extracted from the Web of Science Core Collection. VOSviewer, Citespace, and Bibliometrics online platforms were used to visualize hot topics and global trends in RCC-macrophage research. In total, 778 papers were collected. China produced the most articles; however, the United States accounted for the largest number of citations. Oncology journals published the most articles, and these were cited most frequently. Based on keyword analysis, "prognosis," "immunotherapy," "tumor microenvironment," and "immune infiltration" represented the primary research hotspots. In summary, RCC-macrophage studies have emerged as a key research focus; particularly, incorporating multiomics data and applying artificial intelligence for predictive modeling have demonstrated significant potential. Our study suggests that the resistance mechanism of immune checkpoint inhibitors and the interaction between macrophages and immune checkpoint inhibitors will be pivotal areas for future research.

The Presence and Pathogenic Roles of M(IL-33 + IL-2) Macrophages in Allergic Airway Inflammation

BACKGROUND

Macrophages, one of the most abundant immune cells in the lung, have drawn great attention in allergic asthma. Currently, most studies emphasize alternative activated (M2) polarization bias. However, macrophage function in allergic asthma is still controversial. Interleukin (IL)-9 contributes to the development and pathogenesis of allergic airway inflammation. We sought to investigate the IL-9-producing macrophage and its role in allergic asthma.

METHODS

The model of ovalbumin (OVA)-induced allergic airway inflammation was employed to evaluate IL-9 production in macrophages of lung tissues. We used 22 cytokines or stimuli to screen for IL-9-producing mouse macrophage subset in vitro. Real-time PCR, flow cytometry, ELISA, and RNA-seq to explore the subset. Conditional IL-33 receptor knockout (Lyz-ST2KO) mice and cellular adoptive transfer experiment were used to characterize the potential roles of M(IL-33 + IL-2) in allergic asthma.

RESULTS

We identified a unique pathogenic IL-9-producing macrophage in OVA-induced allergic airway inflammation. We found that only IL-33 significantly induced IL-9 production in mouse macrophages, and IL-2 collaborated with IL-33 to promote IL-9 production, referred to as M(IL-33 + IL-2). Importantly, human monocyte-derived macrophages produced IL-9 after IL-33 and IL-2 stimulation. Using Lyz-ST2KO mice and adoptive transfer of M(IL-33 + IL-2), we found that M(IL-33 + IL-2) significantly promoted pathogenesis in OVA-induced allergic airway inflammation. M(IL-33 + IL-2) has a distinctive gene expression profile with high expression of IL-9, IL-5, and IL-13 and its polarization is dependent on JAK2-STAT3-IRF1 pathway.

CONCLUSIONS

The identification of M(IL-33 + IL-2) subset extends the diversity and heterogeneity of macrophage subsets and may offer novel therapeutic strategies for the treatment of allergic inflammation.

Form-deprivation myopia promotes sclera M2-type macrophages polarization in mice

PURPOSE

To explore the phenotype of sclera macrophages in form-deprivation (FD) myopia mice and the effects of M2 macrophage in FD myopia development.

METHODS

C57BL/6 mice were under 2 weeks of unilateral FD treatment. and they were separated into two groups, including an intraperitoneally injected(IP) vehicle group and Panobinostat (LBH589) (10 mg/kg per body weight) treatment group. All biometric parameters were measured before and after treatments, and the type and density of sclera macrophages were identified by immunofluorescence and RT-qPCR. In vitro, we analyzed the M2 macrophage and primary human sclera fibroblast (HSF) co-culture system by using the transcriptome sequencing method. Gene ontology (GO) and KEGG enrichment analyses were used to pinpoint the biological functions and pathways associated with the identified Differentially Expressed Genes (DEGs). The hub genes were investigated using the STRING database and Cytoscape software and were confirmed using RT-qPCR.

RESULTS

We found that the M2-type sclera macrophage density and expression increased in FD-treated eyes. The results showed that LBH589 inhibited the M2 macrophage polarization, and reduced FDM development. GO and KEGG analyses revealed that the DEGs were predominantly involved in the synthesis and breakdown of the extracellular matrix (ECM), as well as in pathways related to ECM-receptor interaction and the PI3K-Akt signaling pathway. Five hub genes (FN-1, MMP-2, COL1A1, CD44, and IL6) were identified, and RT-qPCR validated the variation in expression levels among these genes.

CONCLUSION

M2 macrophage polarization occurred in the sclera in FDM mice. Panobinostat-mediated inhibition of M2 macrophage polarization may decrease FDM progression, as M2 macrophages are crucial in controlling ECM remodeling by HSFs.

Long-term expanded hepatic progenitor cells ameliorate D-GalN/LPS-induced acute liver failure through repolarizing M1 macrophage to M2-Like phenotype via activation of the IL-10/JAK2/STAT3 signaling pathway

Acute liver failure (ALF) is a devastating liver disease characterized by the rapid deterioration of hepatocytes, which causes a series of clinical complications, including hepatic dysfunction, coagulopathy, encephalopathy, and multiorgan failure. Cell-based therapy is a promising alternative as it can bridge patients until their livers regenerate, releasing immunomodulatory molecules to suppress inflammation. This study reports an iPSCs-derived long-term expanded hepatic progenitor cell (LTHepPCs), which can differentiate into hepatocyte-like cells (HLCs) in vivo. When introduced into drug-induced ALF models, LTHepPCs mitigate liver damage by modulating the local immune microenvironment. This is achieved by shifting macrophages/Kupffer cells towards an anti-inflammatory state, resulting in a decrease in the expression of inflammatory cytokines such as TNF-a, IL-1β, and IL-8, and an increase in the expression of anti-inflammatory cytokines such as IL-10 and ARG-1. In vitro co-culturing of THP-1 or mBMDMs with LTHepPCs suggested that LTHepPCs could activate the anti-inflammatory state of macrophages/Kupffer cells via the IL-10/JAK2/STAT3 signaling pathway. Therefore, LTHepPC transplantation is a promising therapy for ALF patients.

Single-cell view and a novel protective macrophage subset in perivascular adipose tissue in T2DM

BACKGROUND

Vasculopathy underlies diabetic complications, with perivascular adipose tissue (PVAT) playing crucial roles in its development. However, the changes in the cellular composition and function of PVAT, including the specific cell subsets and mechanisms implicated in type 2 diabetes mellitus (T2DM) vasculopathy, remain unclear.

METHODS

To address the above issues, we performed single-cell RNA sequencing on the stromal vascular fraction (SVF) of PVAT from normal and T2DM rats. Then, various bioinformatics tools and functional experiments were used to investigate the characteristic changes in the cellular profile of diabetic PVAT SVF, their implications, and the underlying mechanisms.

RESULTS

Our study reveals the single-cell landscape of the SVF of PVAT, demonstrating its considerable heterogeneity and significant alterations in T2DM, including an enhanced inflammatory response and elevated proportions of macrophages and natural killer (NK) cells. Moreover, macrophages are critical hubs for cross-talk among various cell populations. Notably, we identified a decreased Pdpn+ macrophage subpopulation in the PVAT of T2DM rats and confirmed this in mice and humans. In vitro and in vivo studies demonstrated that Pdpn+ macrophages alleviated insulin resistance and modulated adipokine/cytokine expression in adipocytes via the Pla2g2d-DHA/EPA-GPR120 pathway. This subset also enhances the function of vascular endothelial and smooth muscle cells, inhibits vascular inflammation and oxidative stress, and improves vasodilatory function, thereby protecting blood vessels.

CONCLUSION

Pdpn+ macrophages exhibit significant vascular protective effects by alleviating insulin resistance and modulating adipokine/cytokine expression in PVAT adipocytes. This macrophage subtype may therefore play pivotal roles in mitigating vascular complications in T2DM. Our findings also underscore the critical role of immune-metabolic cross-talk in maintaining tissue homeostasis.

Modulation of the central nervous system immune response and neuroinflammation via Wnt signaling in health and neurodegenerative diseases

The immune response in the central nervous system (CNS) is a highly specialized and tightly regulated process essential for maintaining neural health and protecting against pathogens and injuries. The primary immune cells within the CNS include microglia, astrocytes, T cells, and B cells. They work together, continuously monitor the CNS environment for signs of infection, injury, or disease, and respond by phagocytosing debris, releasing cytokines, and recruiting other immune cells. In addition to providing neuroprotection, these immune responses must be carefully balanced to prevent excessive inflammation that can lead to neuronal damage and contribute to neurodegenerative diseases. Dysregulated immune responses in the CNS are implicated in various neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Wnt signaling is a crucial pathway in the CNS that regulates various cellular processes critical for brain development, function, and maintenance. Despite enhancing immune responses in the health CNS, dysregulated Wnt signaling exacerbates neuroinflammation in the neurodegenerative brains. This review summarized the role of Wnt signaling in regulating immune response under different conditions. We then examined the role of immune response in healthy brains and during the development of neurodegenerative diseases. We also discussed therapeutic intervention in various neurodegenerative diseases through the modulation of the Wnt signaling pathway and neuroinflammation and highlighted challenges and limitations in current clinical trials.