Activated M2 Macrophages Research Articles

Survivin inhibition ameliorates liver fibrosis by inducing hepatic stellate cell senescence and depleting hepatic macrophage population.

Persistent activation of hepatic stellate cells (HSCs) in the injured liver leads to the progression of liver injury from fibrosis to detrimental cirrhosis. In a previous study, we have shown that survivin protein is upregulated during the early activation of HSCs, which triggers the onset of liver fibrosis. However, the therapeutic potential of targeting survivin in a fully established fibrotic liver needs to be investigated. In this study, we chemically induced hepatic fibrosis in mice using carbon tetrachloride (CCl4) for 6weeks, which was followed by treatment with a survivin suppressant (YM155). We also evaluated survivin expression in fibrotic human liver tissues, primary HSCs, and HSC cell line by histological analysis. αSMA+ HSCs in human and mice fibrotic liver tissues showed enhanced survivin expression, whereas the hepatocytes and quiescent (qHSCs) displayed minimal expression. Alternatively, activated M2 macrophage subtype induced survivin expression in HSCs through the TGF-β-TGF-β receptor-I/II signaling. Inhibition of survivin in HSCs promoted cell cycle arrest and senescence, which eventually suppressed their activation. In vivo, YM155 treatment increased the expression of cell senescence makers in HSCs around fibrotic septa such as p53, p21, and β-galactosidase. YM155 treatment in vivo also reduced the hepatic macrophage population and inflammatory cytokine expression in the liver. In conclusion, downregulation of survivin in the fibrotic liver decreases HSC activation by inducing cellular senescence and modulating macrophage cytokine expression that collectively ameliorates liver fibrosis.

Interleukin 28A aggravates Con A-induced acute liver injury by promoting the recruitment of M1 macrophages.

Immune-mediated acute hepatic injury is characterized by the destruction of a large number of hepatocytes and severe liver function damage. Interleukin-28A (IL-28A), a member of the IL-10 family, is notable for its antiviral properties. However, despite advances in our understanding of IL-28A, its role in immune-mediated acute injury remains unclear. The present study investigated the role of IL-28A in concanavalin A (Con A)-induced acute immune liver injury. After Con A injection in mice, IL-28A level significantly increased. IL-28A deficiency was found to protect mice from acute liver injury, prolong survival time, and reduce serum aspartate aminotransferase and alanine aminotransferase levels. In contrast, recombinant IL-28A aggravated liver injury in mice. The proportion of activated M1 macrophages was significantly lower in the IL-28A-deficiency group than in the wild-type mouse group. In adoptive transfer experiments, M1 macrophages from WT could exacerbate mice acute liver injury symptoms in the IL-28A deficiency group. Furthermore, the expression of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), IL-12, IL-6, and IL-1β, by M1 macrophages decreased significantly in the IL-28A-deficiency group. Western blotting demonstrated that IL-28A deficiency could limit M1 macrophage polarization by modulating the nuclear factor (NF)-κB, mitogen-activated protein kinase (MAPK), and interferon regulatory factor (IRF) signaling pathways. In summary, IL-28A deletion plays an important protective role in the Con A-induced acute liver injury model and IL-28A deficiency inhibits the activation of M1 macrophages by inhibiting the NF-κB, MAPK, and IRF signaling pathways. These results provide a potential new target for the treatment of immune-related hepatic injury.

Paediatric sepsis survivors are resistant to sepsis-induced long-term immune dysfunction.

Sepsis-surviving adult individuals commonly develop immunosuppression and increased susceptibility to secondary infections, an outcome mediated by the axis IL-33/ILC2s/M2 macrophages/Tregs. Nonetheless, the long-term immune consequences of paediatric sepsis are indeterminate. We sought to investigate the role of age in the genesis of immunosuppression following sepsis. Here, we compared the frequency of Tregs, the activation of the IL-33/ILC2s axis in M2 macrophages and the DNA methylation of epithelial lung cells from post-septic infant and adult mice. Likewise, sepsis-surviving mice were inoculated intranasally with Pseudomonas aeruginosa or by subcutaneous inoculation of the B16 melanoma cell line. Finally, blood samples from sepsis-surviving patients were collected and the concentration of IL-33 and Tregs frequency were assessed. In contrast to 6-week-old mice, 2-week-old mice were resistant to secondary infection and did not show impairment in tumour controls upon melanoma challenge. Mechanistically, increased IL-33 levels, Tregs expansion, and activation of ILC2s and M2-macrophages were observed in 6-week-old but not 2-week-old post-septic mice. Moreover, impaired IL-33 production in 2-week-old post-septic mice was associated with increased DNA methylation in lung epithelial cells. Notably, IL-33 treatment boosted the expansion of Tregs and induced immunosuppression in 2-week-old mice. Clinically, adults but not paediatric post-septic patients exhibited higher counts of Tregs and seral IL-33 levels. These findings demonstrate a crucial and age-dependent role for IL-33 in post-sepsis immunosuppression. Thus, a better understanding of this process may lead to differential treatments for adult and paediatric sepsis.

The Vagus Nerve Regulates Immunometabolic Homeostasis in the Ovine Fetus near Term: The Impact on Terminal Ileum.

Glucosensing elements are widely distributed throughout the body and relay information about circulating glucose levels to the brain via the vagus nerve. However, while anatomical wiring has been established, little is known about the physiological role of the vagus nerve in glucosensing. The contribution of the vagus nerve to inflammation in the fetus is poorly understood. Increased glucose levels and inflammation act synergistically when causing organ injury, but their interplay remains incompletely understood. We hypothesized that vagotomy (Vx) will trigger a rise in systemic glucose levels and this will be enhanced during systemic and organ-specific inflammation. Efferent vagus nerve stimulation (VNS) should reverse this phenotype. Near-term fetal sheep (n = 57) were surgically prepared using vascular catheters and ECG electrodes as the control and treatment groups (lipopolysaccharide (LPS), Vx + LPS, Vx + LPS + selective efferent VNS). The experiment was started 72 h postoperatively to allow for post-surgical recovery. Inflammation was induced with LPS bolus intravenously (LPS group, 400 ng/fetus/day for 2 days; n = 23). For the Vx + LPS group (n = 11), a bilateral cervical vagotomy was performed during surgery; of these n = 5 received double the LPS dose, LPS800. The Vx + LPS + efferent VNS group (n = 8) received cervical VNS probes bilaterally distal from Vx in eight animals. Efferent VNS was administered for 20 min on days 1 and 2 +/10 min around the LPS bolus. Fetal arterial blood samples were drawn on each postoperative day of recovery (-72 h, -48 h, and -24 h) as well as at the baseline and seven selected time points (3-54 h) to profile inflammation (ELISA IL-6, pg/mL), insulin (ELISA), blood gas, and metabolism (glucose). At 54 h post-LPS, a necropsy was performed, and the terminal ileum macrophages' CD11c (M1 phenotype) immunofluorescence was quantified to detect inflammation. The results are reported for p < 0.05 and for Spearman R2 > 0.1. The results are presented as the median (IQR). Across the treatment groups, blood gas and cardiovascular changes indicated mild septicemia. At 3 h in the LPS group, IL-6 peaked. That peak was decreased in the Vx + LPS400 group and doubled in the Vx + LPS800 group. The efferent VNS sped up the reduction in the inflammatory response profile over 54 h. The M1 macrophage activity was increased in the LPS and Vx + LPS800 groups only. The glucose and insulin concentrations in the Vx + LPS group were, respectively, 1.3-fold (throughout the experiment) and 2.3-fold higher vs. control (at 3 h). The efferent VNS normalized the glucose concentrations. The complete withdrawal of vagal innervation resulted in a 72-h delayed onset of a sustained increase in glucose for at least 54 h and intermittent hyperinsulinemia. Under the conditions of moderate fetal inflammation, this was related to higher levels of gut inflammation. The efferent VNS reduced the systemic inflammatory response as well as restored both the concentrations of glucose and the degree of terminal ileum inflammation, but not the insulin concentrations. Supporting our hypothesis, these findings revealed a novel regulatory, hormetic, role of the vagus nerve in the immunometabolic response to endotoxin in near-term fetuses.

Targeting STAT3 in tumor-associated antigen-presenting cells as a strategy for kidney and bladder cancer immunotherapy.

Immune checkpoint blockade (ICB) improved clinical outcomes in renal and bladder cancer patients, but the response rates remain limited especially in metastatic disease. While STAT3 transcription factor is well-known master regulator of tumor immune evasion, little is known about the role of STAT3 in the resistance of renal or bladder cancers to immunotherapy. To better understand immune alterations associated with ICB resistance, we assessed blood biomarkers in renal cancer patients classified as responders or non-responders to first line nivolumab/ipilimumab immunotherapy. We observed that non-responders showed elevated levels of proinflammatory mediators, such as IL-1RA, IL-6, IL-8 and to lesser extent IL-10, which are associated with STAT3 activation and tumor immunosuppression. In addition, we found STAT3 activation primarily in circulating myeloid immune cells such as tolerogenic MDSCs. To assess whether STAT3 inhibition within these cell subsets can promote antitumor immune responses and/or enhance sensitivity to ICB in vivo, we used an original antisense oligonucleotide (ASO) strategy for myeloid-cell selective STAT3 knockdown (CpG-STAT3ASO). Our results in syngeneic models of renal and bladder cancers in mice demonstrated potent antitumor activity of CpG-STAT3ASO alone in contrast to PD1 blockade alone in both models. The CpG-STAT3ASO/anti-PD1 combination improved therapeutic efficacy especially against bladder tumors. Therapeutic efficacy correlated with activation of dendritic cells (DCs) and M1 macrophages in the tumor microenvironment, reduced percentages of regulatory T cells (Tregs) and the expansion of CD8 T cells in both tumor models. Our study underscores the potential of using myeloid-cell targeted CpG-STAT3 inhibitors for genitourinary cancer therapy to disrupt tolerogenic signaling, restore immune cell activity and sensitivity to immune checkpoint inhibitors and/or T cell-based immunotherapies.

Glutamine Protects against Mouse Abdominal Aortic Aneurysm through Modulating VSMC Apoptosis and M1 Macrophage Activation.

Glutamine (Gln), known as the most abundant free amino acid, is widely spread in human body. In this study, we demonstrated the protective effects of glutamine against mouse abdominal aortic aneurysm (AAA) induced by both angiotensin II (AngII) and calcium phosphate (Ca3(PO4)2) in vivo, which was characterized with lower incidence of mouse AAA. Moreover, histomorphological staining visually presented more intact elastic fiber and less collagen deposition in abdominal aortas of mice treated by glutamine. Further, we found glutamine inhibited the excessive production of reactive oxide species (ROS), activity of matrix metalloproteinase (MMP), M1 macrophage activation, and apoptosis of vascular smooth muscle cells (VSMCs) in suprarenal abdominal aortas of mice, what's more, the high expressions of MMP-2 protein, MMP-9 protein, pro-apoptotic proteins, and IL-6 as well as TNF-α in protein and mRNA levels in cells treated by AngII were down-regulated by glutamine. Collectively, these results revealed that glutamine protected against mouse AAA through inhibiting apoptosis of VSMCs, M1 macrophage activation, oxidative stress, and extracellular matrix degradation.

Analysis of clinical cure outcome, macrophages number, cytokines levels and expression of annexin-A1 in the cutaneous infection in patients with Leishmania braziliensis.

Leishmania braziliensis, a protozoan prevalent in Brazil, is the known causative agent of cutaneous leishmaniasis (CL). The activation of M1 macrophages is a pivotal factor in the host's ability to eliminate the parasite, whereas M2 macrophages may facilitate parasite proliferation. This study analyzed the clinical outcomes of CL and the patients' immunological profiles, focusing on the prevalence of M1 and M2 macrophages, cytokine production, and annexin-A1 (ANXA1) expression in the lesion. Data were obtained by polymerase chain reaction (PCR) and histopathological, immunofluorescence, and cytokine analyses. Patients with exudative and cellular reaction-type (ECR)-type lesions that healed within 90 days showed a significant increase in M1. Conversely, patients with ECR and exudative and granulomatous reaction (EGR)types, who healed within 180 days, showed an elevated number of M2. Cytokines interferon (IFN)-γ and tumor necrosis factor (TNF)-α were higher in ECR lesions that resolved within 90 days (P<0.05). In contrast, IL-9 and IL-10 levels significantly increased in both ECR and EGR lesions that healed after 180 days (P<0.001). The production of IL-21, IL-23 and TGF-β was increased in patients with ECR or EGR lesions that healed after 180 days (P<0.05). The expression of ANXA1 was higher in M2 within ECR-type lesions in patients who healed after 180 days (P<0.05). These findings suggest that the infectious microenvironment induced by L. braziliensis affects the differentiation of M1 and M2 macrophages, cytokine release, and ANXA1 expression, thereby influencing the healing capacity of patients. Therefore, histopathological and immunological investigations may improve the selection of CL therapy.

A responsive hydrogel modulates innate immune cascade fibrosis to promote ocular surface reconstruction after chemical injury

Following an ocular chemical injury, the release of neutrophil extracellular traps (NETs) triggers an innate immune cascade fibrotic effect involving macrophages (Mø), which limits corneal repair. However, the interplay and mechanisms between NETs and macrophages, as well as the coordination between the innate immunity and corneal repair, remain challenging issues. Using a co-culture system, we report that chemical stimulation exacerbates the accumulation of reactive oxygen species (ROS) within the polymorphonuclear neutrophils, leading to NET formation and the activation of M2 macrophages, ultimately inducing pathological fibrosis of the ocular surface through the IL-10/STAT3/TGF-β1/Smad2 axis. Inspired by the locally formed acidic microenvironment mediated by innate acute inflammatory stimulation, we further integrate sericin with oxidized chitosan nanoparticles loaded with black phosphorus quantum dots (BPQDs) using Schiff base chemistry to construct a functional pH-responsive hydrogel. Following corneal injury, the hydrogel selectively releases BPQDs in response to the acidic environment, inhibiting the innate immune cascade fibrosis triggered by the PMN-ROS-NETs. Thus, corneal pathological fibrosis is alleviated and reshaping of the ocular surface takes place. These results represent a refinement of the mechanism of inherent immune effector cell interactions, and provide new research ideas for the construction of nano biomaterials that regulate pathological fibrosis.

Targeting the serum marker interleukin 9 improves the underlying characterization and immune homeostasis in rheumatoid arthritis.

Rheumatoid factor (RF) and anti-citrullinated peptide antibodies (ACPA) are serological markers used for diagnosing rheumatoid arthritis (RA), an autoimmune disease characterized by inflammatory joint damage. However, there is a subset of RA patients who test negative for both RF and ACPA, known as seronegative rheumatoid arthritis (SNRA). The levels of serum markers were examined in both clinical samples and a rat model of type II collagen-induced RA (CIA). The effect of interleukin 9 (IL-9) on RA was investigated using recombinant rat IL-9 (rrIL-9), anti-rat IL-9 neutralizing monoclonal antibody (mAb), and control IgG antibody in the CIA rat. The severity of arthritis was assessed. Treg and Th17 cells, M1 and M2 macrophages, and inflammatory cytokine levels were analyzed. We observed higher levels of IL-9 in clinical samples from SNRA patients compared to the normal group. Rat models of CIA exhibit increased arthritis scores, weight loss, paw swelling, and severe joint damage. IL-9 was the most sensitive serum marker for the diagnosis of RA in serum assays of CIA rats. IL-9 increased arthritis scores and cartilage damage, whereas treatment with IL-9 inhibitors produced the opposite effect. IL-9 inhibitors promoted Treg/Th17 homeostasis, decreased M1 macrophages, increased M2 macrophages, and decreased levels of inflammatory cytokines in joint tissues. These results suggest that IL-9 has potential as a diagnostic marker for SNRA. Inhibition of IL-9 could reduce the severity of arthritis in CIA rats by ameliorating inflammation and modulating the Treg/Th17 immune balance, M2 and M1 macrophage activation.

The Effect Mechanism of N6-adenosine Methylation (m6A) in Melatonin Regulated LPS-induced Colon Inflammation.

Colon inflammation is characterized by disturbances in the intestinal microbiota and inflammation. Melatonin (Mel) can improve colon inflammation. However, the underlying mechanism remains unclear. Recent studies suggest that m6A methylation modification may play an important role in inflammatory responses. This study aimed to explore the effects of melatonin and LPS-mediated m6A methylation on colon inflammation. Our study found that melatonin inhibits M1 macrophages, activates M2 macrophages, inhibit the secretion of pro-inflammatory factors, maintain colon homeostasis and improves colon inflammation through MTNR1B. In addition, the increased methylation level of m6A is associated with the occurrence of colon inflammation, and melatonin can also reduce the level of colon methylation to improve colon inflammation. Among them, the main methylated protein METTL3 can be inhibited by melatonin through MTNR1B. In a word, melatonin regulates m6A methylation by improving abnormal METTL3 protein level to reshape the microflora and activate macrophages to improve colon inflammation, mainly through MTNR1B.

Ion-incorporated titanium implants for staged regulation of antibacterial activity and immunoregulation-mediated osteogenesis.

Antibacterial properties and osteogenic activity are considered as two crucial factors for the initial healing and long-term survivability of orthopedic implants. For decades, various drug-loaded implants to enhance biological activities have been investigated extensively. More importantly, to control the drug release timing is equally significant due to the sequential biological processes after implantation. Hence, developing a staged regulation system on the titanium surface is practically significant. Here, we prepared TiO2 nanotubes (TiO2 NTs) on the titanium surface by anodization, followed by the incorporation of zinc (Zn) and strontium (Sr) sequentially through a hydrothermal process. Surface characterization confirmed the successful fabrication of Zn and Sr-incorporated TiO2 NTs (Zn-Sr/TiO2) on the titanium surface. The ion release results exhibited the differential releasecharacteristicof Zn and Sr, which meant the early-stage release of Zn and the long-term release of Sr. It was exactly in accord withthe biological process after implantation, laying the basis of staged regulation after implantation. Zn-Sr/TiO2 showed favorable anti-early infection properties both in vitro and in vivo. Its inhibition effect on bacterial biofilm formation was attributed to the resistance against bacteria's initial adhesion and the killing effect on planktonic bacteria. Additionally, the release of Sr could alleviate infection-induced damage via immunoregulation. The biocompatibility and osteogenic activity mediated by M2 macrophage activation were confirmed with in vitro and in vivo studies. Therefore, it exhibited great potential in staged regulation for antibacterial activity in the early stage and the M2 activation-mediated osteogenic activity in the late stage. The staged regulation process was based on the differential release of Zn and Sr to achieve the early antibacterial effect and the long-term immune-induced osteogenic activity, to prevent implant-related infection and achieve better osseointegration. These two kinds of ions played their roles synergistically and complement mutually. This work is expected to provide an innovative idea for realizing sequential regulation after implantation.

Immunotherapeutic IL-6R and targeting the MCT-1/IL-6/CXCL7/PD-L1 circuit prevent relapse and metastasis of triple-negative breast cancer.

Rationale: Multiple copies in T-cell malignancy 1 (MCT-1) is a prognostic biomarker for aggressive breast cancers. Overexpressed MCT-1 stimulates the IL-6/IL-6R/gp130/STAT3 axis, which promotes epithelial-to-mesenchymal transition and cancer stemness. Because cancer stemness largely contributes to the tumor metastasis and recurrence, we aimed to identify whether the blockade of MCT-1 and IL-6R can render these effects and to understand the underlying mechanisms that govern the process. Methods: We assessed primary tumor invasion, postsurgical local recurrence and distant metastasis in orthotopic syngeneic mice given the indicated immunotherapy and MCT-1 silencing (shMCT-1). Results: We found that shMCT-1 suppresses the transcriptomes of the inflammatory response and metastatic signaling in TNBC cells and inhibits tumor recurrence, metastasis and mortality in xenograft mice. IL-6R immunotherapy and shMCT-1 combined further decreased intratumoral M2 macrophages and T regulatory cells (Tregs) and avoided postsurgical TNBC expansion. shMCT-1 also enhances IL-6R-based immunotherapy effectively in preventing postsurgical TNBC metastasis, recurrence and mortality. Anti-IL-6R improved helper T, cytotoxic T and natural killer (NK) cells in the lymphatic system and decreased Tregs in the recurrent and metastatic tumors. Combined IL-6R and PD-L1 immunotherapies abridged TNBC cell stemness and M2 macrophage activity to a greater extent than monotherapy. Sequential immunotherapy of PD-L1 and IL-6R demonstrated the best survival outcome and lowest postoperative recurrence and metastasis compared with synchronized therapy, particularly in the shMCT-1 context. Multiple positive feedforward loops of the MCT-1/IL-6/IL-6R/CXCL7/PD-L1 axis were identified in TNBC cells, which boosted metastatic niches and immunosuppressive microenvironments. Clinically, MCT-1high/PD-L1high/CXCL7high and CXCL7high/IL-6high/IL-6Rhigh expression patterns predict worse prognosis and poorer survival of breast cancer patients. Conclusion: Systemic targeting the MCT-1/IL-6/IL-6R/CXCL7/PD-L1 interconnections enhances immune surveillance that inhibits the aggressiveness of TNBC.

Иммунные механизмы нейтрофильного воспаления при бронхиальной астме

This review presents an analysis of scientific publications in recent years devoted to the study of cellular and molecular mechanisms of neutrophilic airway inflammation as potential therapeutic targets in the treatment of severe, poorly controlled asthma of the neutrophil phenotype, the presence of which is still debated and there is no generally accepted definition. The conditional term "neutrophilic asthma" implies the existence of a certain asthma endotype, in which neutrophils are the main type of cells mediating the pathophysiology and disease symptoms. The involvement of the inverted protein response associated with endoplasmic reticulum (ER) stress and the sensory signal transduction protein in the endoplasmic reticulum membrane in the deregulation of the T helper 17 (Th17) cells function and neutrophilic airway inflammation is considered. Polarization and activation of M1 macrophages play an important role in the neutrophilic inflammation immunopathogenesis, in particular, in asthma associated with obesity. Soluble suppression of tumorigenicity 2 protein is considered as a receptor that promotes neutrophil activation and neutrophilic inflammation. The involvement of neutrophil extracellular traps and the respiratory tract microbiome in the neutrophilic inflammation progression, in particular, the role of bacterial outer membrane vesicles, is discussed. KEYWORDS: neutrophils, neutrophilic inflammation, asthma, Th17 cells, M1 macrophages, suppression of tumorigenicity 2 protein, neutrophil extracellular traps, respiratory tract microbiome. FOR CITATION: Kuzubova N.A., Lebedeva E.S. Immune mechanisms of neutrophilic inflammation in asthma. Russian Medical Inquiry. 2024;8(8):453–458 (in Russ.). DOI: 10.32364/2587-6821-2024-8-8-2.

Inhibition of cGAS-STING pathway by stress granules after activation of M2 macrophages by human mesenchymal stem cells against drug induced liver injury

ObjectiveCells can produce stress granules (SGs) to protect itself from damage under stress. The cGAS-STING pathway is one of the important pattern recognition pathways in the natural immune system. This study was investigated whether human mesenchymal stem cells (hMSCs) could protect the liver by inducing M2 macrophages to produce SGs during acute drug induced liver injury (DILI) induced by acetaminophen (APAP). MethodsAfter intragastric administration of APAP in vivo to induce DILI mice model, hMSCs were injected into the tail vein. The co-culture system of hMSCs and M2 macrophages was established in vitro. It was further use SGs inhibitor anisomicin to intervene M2 macrophages. The liver histopathology, liver function, reactive oxygen species (ROS) level, apoptosis pathway, endoplasmic reticulum stress (ERS) level, SGs markers (G3BP1/TIA-1), cGAS-STING pathway, TNF-α, IL-6, IL-1β mRNA levels in liver tissue and M2 macrophages were observed. ResultsIn vivo experiments, it showed that hMSCs could alleviate liver injury, inhibite the level of ROS, apoptosis and ERS, protect liver function in DILI mice. The mount of M2 was increased in the liver. hMSCs could also induce the production of SGs, inhibit the cGAS-STING pathway and reduce TNF-α, IL-6, IL-1β mRNA expression. The results in vitro showed that hMSCs could induce the production of SGs in macrophages, inhibit the cGAS-STING pathway, promote the secretion of IL-4 and IL-13, and reduce TNF-α, IL-6, IL-1β mRNA level in cells. In the process of IL-4 inducing M2 macrophage activation, anisomycin could inhibit the production of SGs, activate the cGAS-STING pathway, and promote the inflammatory factor TNF-α, IL-6, IL-1β mRNA expression in cells. ConclusionsHMSCs had a protective effect on acute DILI in mice induced by APAP. Its mechanism might involve in activating M2 type macrophages, promoting the production of SGs, inhibiting the cGAS-STING pathway, and reducing the expression of pro-inflammatory factors in macrophages, to reduce hepatocytes damage.

Targeting acid ceramidase enhances antitumor immune response in colorectal cancer

IntroductionAcid ceramidase (hereafter referred as ASAH1) is an enzyme in sphingolipid metabolism that converts pro-survival ceramide into sphingosine. ASAH1 has been shown to be overexpressed in certain cancers. However, the role of ASAH1 in colorectal cancer still remain elusive. ObjectiveThe present study is aimed to understand how ASAH1 regulates colorectal cancer (CRC) progression and resistance to checkpoint inhibitor therapy. MethodsBoth pharmacological and genetic silencing of ASAH1 was used in the study. In vitro experiments were done on human and mouse CRC cell lines. The in vivo studies were conducted in NOD-SCID and BALB/c mice models. The combination of ASAH1 inhibitor and checkpoint inhibitor was tested using a syngeneic tumor model of CRC. Transcriptomic and metabolomic analyses were done to understand the effect of ASAH1 silencing. ResultsASAH1 is overexpressed in human CRC cases, and silencing the expression resulted in the induction of immunological cell death (ICD) and mitochondrial stress. The ASAH1 inhibitor (LCL-521), either as monotherapy or in combination with an anti-PD-1 antibody, resulted in reduction of tumors and, through induction of type I and II interferon response, activation of M1 macrophages and T cells, leading to enhanced infiltration of cytotoxic T cells. Our findings supported that the combination of LCL-521 and ICIs, which enhances the antitumor responses, and ASAH1 can be a druggable target in CRC.

ADAR1 regulates macrophage polarization and is protective against liver ischemia and reperfusion injury

Liver ischemia and reperfusion injury (LIRI) is a major risk for the poor prognosis of patients receiving liver transplantation. The molecular mechanism involved in LIRI is complex and related to various cellular components. We previously reported that adenosine deaminase acting on RNA 1 (ADAR1) alleviated the allogeneic skin graft rejection by regulating macrophage polarization. However, the regulatory effects of ADAR1 on liver macrophages after LIRI remain largely unknown. In this study, we mainly adopted a mouse model of LIRI and cellular experiments with hypoxia and reoxygenation (HR) treatment to explore the regulatory roles of ADAR1 on liver macrophages under LIRI conditions. We found that IRI caused decreased ADAR1 in liver tissues and remarkable changes of liver macrophage polarization and profiles. ADAR1 supplementation alleviated the pathological injury caused by IRI and accelerated the activation of M2 macrophages in the liver of IRI mice. Increased hypoxia duration reduced ADAR1 expression levels in murine RAW264.7 macrophages at the transcriptional level. Further overexpression of ADAR1 significantly increased the expressions of anti-inflammatory cytokines and promoted M2 polarization of macrophages under HR exposure. ADAR1 knockdown exhibited opposite effects on macrophage polarization. Hence, ADAR1 promotes the M2 polarization of liver macrophages that may further alleviate LIRI. The protective effects of ADAR1 against LIRI provide a novel insight into the prevention and treatment of LIRI.

Activation of GPER1 in macrophages ameliorates UUO-induced renal fibrosis

Numerous studies have proven the critical role of macrophages in the renal fibrosis process. Notably, G Protein-coupled Estrogen Receptor 1 (GPER1), a novel estrogen receptor, has been shown to play a ubiquitous role in regulating macrophage activities and proinflammatory pathways. However, the precise role of GPER1 in macrophage-mediated renal fibrosis is unknown. In this study, we aimed to investigate the function of macrophage GPER1 in the UUO-induced renal fibrosis model. Compared to vehicle-treated ovariectomized (OVX) female and male unilateral ureteral obstruction (UUO) models, we observed that G-1 (GPER1 agonist)-treated OVX female and male UUO mice had fewer renal fibrotic lesions and less M1 and M2 macrophage infiltration in the kidney tissues. Conversely, Gper1 deletion in male UUO mice accelerated renal fibrosis and increased inflammation. In vitro studies also revealed that GPER1 activation reduced M0 macrophage polarization towards M1 or M2 phenotypes. The RNA-sequencing analysis and immunoblotting indicated that GPER1 activation was primarily involved in downregulating immune pathways activation and inactivating MAPK pathways. Tubular epithelial cells co-cultured with G-1-pretreated M1 macrophages exhibited fewer injuries and immune activation. In addition, fibroblasts co-cultured with G-1-pretreated M2 macrophages showed downregulated extracellular matrix expression. Overall, this is the first study to demonstrate the effect of GPER1 on macrophage-mediated renal fibrosis via inhibition of M1 and M2 macrophage activation. These findings indicate that GPER1 may be a promising therapeutic target for treating renal fibrosis.

Abstract A022: Immunotherapy of IL-6R Prevents Relapse and Metastasis of Triple-Negative Breast Cancer

Abstract Multiple Copies in T-cell Malignancy-1 (MCT-1 or MCTS1) is a prognostic biomarker for aggressive breast cancers. Overexpressed MCT-1 stimulates the IL-6/IL-6R/gp130/STAT3 axis, promoting epithelial-to-mesenchymal transition, cancer cell stemness and tumor progression. To study the mechanism underlying TNBC immunity and aggressiveness, TNBC cell lines with different MCT-1 expression levels were evaluated. Primary tumor invasion and postsurgical local recurrence and distant metastasis were assessed in orthotopic syngeneic mice given indicated immunotherapy and/or MCT-1 silencing (shMCT-1). We found that shMCT-1 suppresses the transcriptome of inflammatory response and metastatic signaling in TNBC cells and inhibits TNBC progression, metastasis and mortality in xenograft mice. Combined IL-6R immunotherapy and shMCT-1 effect further decreased intratumoral M2 macrophages and T regulatory cells (Tregs) and avoided postsurgical TNBC expansion. Multiple positive feedback loops of the MCT-1/IL-6/IL-6R/CXCL7/PD-L1 axis were identified in TNBC cells, which boost metastatic niches and immunosuppressive microenvironments. MCT-1high/PD-L1high/CXCL7high and CXCL7high/IL-6high/IL-6Rhigh expression patterns predict worse prognosis and poorer survival in breast cancer patients. IL-6R-based immunotherapy more effectively prevented postsurgical TNBC metastasis, recurrence and mortality than anti-PD-L1 immunotherapy. Anti-IL-6R improved helper T, cytotoxic T and natural killer (NK) cells in lymphatic system and decreased Tregs in the recurrent and metastatic tumors, but anti-PD-L1 incapably elevated NK cells. Combined IL-6R and PD-L1 immunotherapies abridged TNBC cell stemness and M2 macrophage activity better than monotherapy. Sequential immunotherapy of PD-L1 and IL-6R demonstrated the best survival outcome, lowest postoperative recurrence and metastasis than synchronized therapy, particularly in shMCT-1 context. Conclusion: Systemic targeting of the MCT-1/IL-6/IL-6R/CXCL7/PD-L1 interconnection enhances the immune surveillance that inhibits aggressiveness of TNBC. Citation Format: Aushia Tanzih Al Haq, Pao-Pao Yang, Christopher Jin, Jou-Ho Shih, Li-Mei Chen, Lu-Hai Wang, Michael P. Snyder, Hsin-Ling Hsu. Immunotherapy of IL-6R Prevents Relapse and Metastasis of Triple-Negative Breast Cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2023 Oct 1-4; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Cancer Immunol Res 2023;11(12 Suppl):Abstract nr A022.

Mesenchymal stem cell therapy modulates macrophage dynamics in ARDS-associated liver injury in rats

Acute Respiratory Distress Syndrome (ARDS) is a life-threatening pulmonary condition characterized by severe hypoxemia and respiratory failure. Beyond its devastating impact on the lungs, ARDS often triggers systemic responses affecting vital organs throughout the body. One such organ commonly affected is the liver, which experiences various degrees of injury during the course of ARDS. Pathophysiological changes in liver during ARDS, particularly polarization of Kupffer cells during the disease and its treatment, have drawn increasing attention. Purpose. To explore the macrophage transformation in liver injury associated with ARDS and investigate the potential of mesenchymal stem cell (MSC) therapy as a means to modulate macrophage responses and mitigate liver injury. Materials and methods. 72 mature male Wistar rats were randomly allocated to nine experimental groups as follows: the control group, groups assessed at 3 days, 7 days, and 28 days following intranasal LPS administration, groups that received 24 hours of LPS followed by 2 days of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs), groups exposed to 4 days of LPS and 3 days of hUC-MSCs, groups subjected to 14 days of LPS and 14 days of hUC-MSCs, groups treated with LPS 21 days and 7 days with hUC-MSCs injection, and a control group assessed 3 days after hUC-MSCs injection. For the administration of hUC-MSCs, intraperitoneal injections were performed at a dose of 1∙106 cells/kg body weight. Immunohistochemistry was employed to analyze macrophage subpopulations in liver tissues. Animal experiments adhered to ethical guidelines. Results. Early ARDS stages showed increased M1 macrophages, indicating pro-inflammatory responses, while later stages showed M2 macrophage activation, suggestive of anti-inflammatory and tissue repair roles. MSC administration facilitated the transition from M1 to M2 macrophages, promoting an anti-inflammatory milieu. Conclusions. MSCs demonstrate the potential to modulate macrophage polarization into M2 anti-inflammatory phenotype. Such findings reflect one of the mechanisms of MSC action which holds practical significance for future ARDS therapies, aiming to mitigate excessive inflammation and enhance tissue repair.

Cytokine and Mutation Profiling Reveal Patterns of Complete Remission Rates with Lenzilumab Combination Therapy in Chronic Myelomonocytic Leukemia

Introduction: Chronic myelomonocytic leukemia (CMML) is characterized by accumulation of classical CD14+CD16- inflammatory monocytes driven in part by hypersensitivity to granulocyte-macrophage colony-stimulating factor (GM-CSF), a pro-inflammatory cytokine. Standard of care in CMML includes hypomethylating agents such as azacytidine (AZA), with complete response (CR) rates of 16-21% 1,2 and no reliable biomarkers that predict response. The complete pro-inflammatory profile of CMML is unknown and no treatment addresses the hematologic aberrations of CMML. Lenzilumab (LENZ; Humanigen, Inc., Short Hills, NJ) is a proprietary Humaneered ® first-in-class monoclonal antibody with best-in-class off-rate and affinity that neutralizes GM-CSF. The interim analysis of the PREcision Approach to CHronic Myelomonocytic Leukemia (PREACH-M; ACTRN12621000223831) trial showed LENZ/AZA treatment in 11 subjects with RAS-pathway ( NRAS/ KRAS/ CBL) mutations resulted in 8 subjects with complete response or optimal marrow response and improvements in hematological parameters. This report describes the cytokine profiles and systemic C-reactive protein levels of these subjects. Methods: PREACH-M is a Phase 2/3 non-randomized, open-label trial in 72 subjects, aged at least 18 years, with newly diagnosed CMML based on the WHO 2016 criteria; and RAS-pathway mutations at a variant allele frequency ≥3%. Subjects received 24 cycles (every 28 days) of AZA (SC; 75 mg/m 2 for 7 days) and LENZ (IV; 552 mg; d1 &amp; d15 of cycle 1 and d1 only for all subsequent cycles). Subjects without RAS-pathway mutations received the same AZA regimen and sodium ascorbate (IV; 30g for 7 days (15g for 1st dose only; 30g thereafter if no evidence of tumor lysis syndrome); PO; 1.1g on all other days). Cytokine profiling from bone marrow plasma was performed after 4,7,12 and 24 months using Milliplex Human Cytokine/Chemokine Magnetic bead panel and compared with 24 age-matched healthy subjects. Unsupervised hierarchical clustering with Ward's method sought distinct CMML patterns based on cytokine expression. C-reactive protein (CRP) was determined from blood samples using a routine assay. Variant allele frequencies were determined from bone marrow mononuclear cells using a 41-myeloid panel using Illumina Hi-Seq with a depth of 1000x. Results: As of July 2023, 15 subjects were enrolled in the LENZ/AZA arm (8 females, 7 males with mean age 69; mean white cell count, 21x10 9/L; mean Hb, 121 g/L, mean platelet count; 74x10 9/L, mean blast count, 10.1%). CRP decreased from a median of 5.6 at baseline to 2.1 mg/L after 6 months of LENZ/AZA (P=0.02). GM-CSF and other pro-inflammatory cytokines were increased in CMML bone marrow plasma compared with healthy subjects. Hierarchical clustering of all subjects revealed 2 patterns of CMML, distinct from healthy subjects. Cluster “INNATE-1” was comprised of medium increases in inflammatory cytokines associated with innate immune response and M1 macrophage activation (IFN-g, IL-1b, TNFa, IL-12p70, IL-12p40, IL-17, Fractalkine, MCP-3). Cluster “INNATE-2” was associated with extreme increases of these cytokines. The mean pro-inflammatory innate immune score (sum of z-scores) was 20-fold greater in INNATE-2 compared with INNATE-1 ( P=0.055). Somatic mutations SRSF2, WT1, PHF6 were enriched in INNATE-2. All patients (5/5) in INNATE-1 showed 100% response (CR or optimal marrow response resulting in &amp;lt;5% blasts) to AZA/LENZ. Two subjects (2/6) in INNATE-2 demonstrated partial responses or haematological improvement thus far. Conclusion: CMML is a disorder of profound innate immune activation, driven by GM-CSF and other pro-inflammatory cytokines. Early treatment with LENZ/AZA, a precision immunotherapeutic approach, leads to a) efficacy in INNATE-1 that exceeds historical CR rates for hypomethylating agents 1,2; and b) evolving efficacy in INNATE-2, in which pro-inflammatory activity is more robust. 1. Xu Y, Guo R, Miao M, Zhang G, Lan J, Jin J. Real-world data on efficacy and safety of azacitidine therapy in chronic myelomonocytic leukemia in China: results from a multicenter, retrospective study. Invest New Drugs 2022;40(5):1117-1124. DOI: 10.1007/s10637-022-01283-x. 2. Zheng X, Lv L, Li X, Jiang E. Efficacy and Safety of Hypomethylating Agents in Chronic Myelomonocytic Leukemia: A Single-Arm Meta-analysis. Glob Med Genet 2022;9(2):141-151. DOI: 10.1055/s-0042-1744157.