Modulation of Macrophage Polarization by Viruses: Turning Off/On Host Antiviral Responses

Transcriptome profiling of macrophages persistently infected with human respiratory syncytial virus and effect of recombinant Taenia solium calreticulin on immune-related genes

Introduction

Human respiratory syncytial virus (hRSV) is a main cause of bronchiolitis in infants and its persistence has been described in immunocompromised subjects. However, limited evidence has been reported on the gene expression triggered by the hRSV and the effect of recombinant Taenia solium-derived calreticulin (rTsCRT).

Methods

Using a comprehensive microarray approach, we analyzed the transcriptome profile of a macrophage cell line that has supported hRSV persistence for over 150 passages. We compared the gene expression of persistently infected and non-infected macrophages. We also evaluated the effect of rTsCRT on hRSV-infected macrophage gene transcription, as well as on cytokine production and number of copies of the persistent hRSV genome.

Results

Our analysis showed that hRSV long-term virus infection significantly alters mRNA expression of antiviral, inflammatory, as well as arginine and lipid metabolism-associated genes, revealing a transcriptional signature that suggests a mixed M1/M2 phenotype. The resulting host-virus equilibrium allows for the regulation of viral replication, while evading the antiviral and proinflammatory responses. Interestingly, rTsCRT stimulus upregulated Tnfα, Il6 and Nos2 mRNA. We found increased levels of both proinflammatory cytokines and nitrite levels in the conditioned media of persistent macrophages treated with rTsCRT. This increase was associated with a significant reduction in viral genome copies.

Discussion

hRSV persistently infected macrophages retain responsiveness to external stimuli and demonstrate that the profound changes induced by viral persistence are potentially reversible. Our observations contribute to the understanding of the mechanisms related to hRSV persistence in macrophages and have implications for the development of targeted therapies to eliminate persistent infections or reduce the negative effects related with chronic inflammatory diseases associated with hRSV infection.

Oncolytic virus and tumor-associated macrophage interactions in cancer immunotherapy

Oncolytic viruses (OV) are a promising strategy in cancer immunotherapy. Their capacity to promote anti-tumoral immunity locally raises hope that cancers unresponsive to current immunotherapy approaches could be tackled more efficiently. In this context, tumor-associated macrophages (TAM) must be considered because of their pivotal role in cancer immunity. Even though TAM tend to inhibit anti-tumoral responses, their ability to secrete pro-inflammatory cytokines and phagocytose cancer cells can be harnessed to promote therapeutic cancer immunity. OVs have the potential to promote TAM pro-inflammatory functions that favor anti-tumoral immunity. But in parallel, TAM pro-inflammatory functions induce OV clearance in the tumor, thereby limiting OV efficacy and highlighting that the interaction between OV and TAM is a double edge sword. Moreover, engineered OVs were recently developed to modulate specific TAM functions such as phagocytic activity. The potential of circulating monocytes to deliver OV into the tumor after intravenous administration is also emerging. In this review, we will present the interaction between OV and TAM, the potential of engineered OV to modulate specific TAM functions, and the promising role of circulating monocytes in OV delivery to the tumor.

Overexpression of NLRP12 enhances macrophage immune response and alleviates herpes simplex keratitis

Introduction

Herpes simplex keratitis (HSK) is a blinding disease caused by corneal infection of Herpes simplex virus type 1 (HSV-1). Effective clearance of HSV-1 from the infected cornea is crucial for HSK management. Macrophages play an important part in the innate immune defense against viral infections. This study investigates the immunomodulatory role of NLRP12 in macrophage immune response during HSV-1 infection.

Methods

NLRP12 expression post-infection was assessed in various macrophage cell lines. Overexpression of NLRP12 was achieved by lentiviral transfection, and its effect on HSV-1 replication and immune responses were examined. Mechanistic insights into the role of NLRP12 were explored using immunofluorescence and Western Blot. For in vivo studies, ocular adoptive transfer of NLRP12-overexpressing bone marrow derived macrophages (BMDMs) was performed. HSV-1 viral loads, HSK symptoms, and macrophage-mediated immune responses were investigated.

Results

A significant decrease in NLRP12 expression post-infection was observed in various macrophage cell lines. Overexpression of NLRP12 in macrophages reduced HSV-1 replication. Mechanistically, overexpression of NLRP12 triggered early and robust pyroptosis in response to HSV-1 infection, inducing interleukin (IL)-18 production and activating downstream antiviral responses through the JAK-STAT signaling pathway. In vivo, ocular adoptive transfer of NLRP12-overexpressing BMDMs to mouse corneas alleviated HSK damage and reduced HSV-1 viral loads. NLRP12-overexpressing BMDMs improved antiviral responses in the cornea and promoted the maturation of corneal-infiltrating macrophages and dendritic cells. Additionally, NLRP12-overexpressing BMDMs amplified the adaptive immune response in the submandibular draining lymph nodes.

Discussion

These findings highlight the role of NLRP12 in macrophage-mediated immune response against HSV-1 infection and suggest its potential for possible immunotherapy for HSK.

Deciphering the performance of macrophages in tumour microenvironment: a call for precision immunotherapy

Macrophages infiltrating tumour tissues or residing in the microenvironment of solid tumours are known as tumour-associated macrophages (TAMs). These specialized immune cells play crucial roles in tumour growth, angiogenesis, immune regulation, metastasis, and chemoresistance. TAMs encompass various subpopulations, primarily classified into M1 and M2 subtypes based on their differentiation and activities. M1 macrophages, characterized by a pro-inflammatory phenotype, exert anti-tumoural effects, while M2 macrophages, with an anti-inflammatory phenotype, function as protumoural regulators. These highly versatile cells respond to stimuli from tumour cells and other constituents within the tumour microenvironment (TME), such as growth factors, cytokines, chemokines, and enzymes. These stimuli induce their polarization towards one phenotype or another, leading to complex interactions with TME components and influencing both pro-tumour and anti-tumour processes.This review comprehensively and deeply covers the literature on macrophages, their origin and function as well as the intricate interplay between macrophages and the TME, influencing the dual nature of TAMs in promoting both pro- and anti-tumour processes. Moreover, the review delves into the primary pathways implicated in macrophage polarization, examining the diverse stimuli that regulate this process. These stimuli play a crucial role in shaping the phenotype and functions of macrophages. In addition, the advantages and limitations of current macrophage based clinical interventions are reviewed, including enhancing TAM phagocytosis, inducing TAM exhaustion, inhibiting TAM recruitment, and polarizing TAMs towards an M1-like phenotype. In conclusion, while the treatment strategies targeting macrophages in precision medicine show promise, overcoming several obstacles is still necessary to achieve an accessible and efficient immunotherapy.

Inhibition of NADPH oxidase 2 enhances resistance to viral neuroinflammation by facilitating M1-polarization of macrophages at the extraneural tissues

BACKGROUND

Macrophages play a pivotal role in the regulation of Japanese encephalitis (JE), a severe neuroinflammation in the central nervous system (CNS) following infection with JE virus (JEV). Macrophages are known for their heterogeneity, polarizing into M1 or M2 phenotypes in the context of various immunopathological diseases. A comprehensive understanding of macrophage polarization and its relevance to JE progression holds significant promise for advancing JE control and therapeutic strategies.

METHODS

To elucidate the role of NADPH oxidase-derived reactive oxygen species (ROS) in JE progression, we assessed viral load, M1 macrophage accumulation, and cytokine production in WT and NADPH oxidase 2 (NOX2)-deficient mice using murine JE model. Additionally, we employed bone marrow (BM) cell-derived macrophages to delineate ROS-mediated regulation of macrophage polarization by ROS following JEV infection.

RESULTS

NOX2-deficient mice exhibited increased resistance to JE progression rather than heightened susceptibility, driven by the regulation of macrophage polarization. These mice displayed reduced viral loads in peripheral lymphoid tissues and the CNS, along with diminished infiltration of inflammatory cells into the CNS, thereby resulting in attenuated neuroinflammation. Additionally, NOX2-deficient mice exhibited enhanced JEV-specific Th1 CD4 + and CD8 + T cell responses and increased accumulation of M1 macrophages producing IL-12p40 and iNOS in peripheral lymphoid and inflamed extraneural tissues. Mechanistic investigations revealed that NOX2-deficient macrophages displayed a more pronounced differentiation into M1 phenotypes in response to JEV infection, thereby leading to the suppression of viral replication. Importantly, the administration of H2O2 generated by NOX2 was shown to inhibit M1 macrophage polarization. Finally, oral administration of the ROS scavenger, butylated hydroxyanisole (BHA), bolstered resistance to JE progression and reduced viral loads in both extraneural tissues and the CNS, along with facilitated accumulation of M1 macrophages.

CONCLUSION

In light of our results, it is suggested that ROS generated by NOX2 play a role in undermining the control of JEV replication within peripheral extraneural tissues, primarily by suppressing M1 macrophage polarization. Subsequently, this leads to an augmentation in the viral load invading the CNS, thereby facilitating JE progression. Hence, our findings ultimately underscore the significance of ROS-mediated macrophage polarization in the context of JE progression initiated JEV infection.

GCRV-II invades monocytes/macrophages and induces macrophage polarization and apoptosis in tissues to facilitate viral replication and dissemination

Grass carp reovirus (GCRV), particularly the highly prevalent type II GCRV (GCRV-II), causes huge losses in the aquaculture industry. However, little is known about the mechanisms by which GCRV-II invades grass carp and further disseminates among tissues. In the present study, monocytes/macrophages (Mo/Mφs) were isolated from the peripheral blood of grass carp and infected with GCRV-II. The results of indirect immunofluorescent microscopy, transmission electron microscopy, real-time quantitative RT-PCR (qRT-PCR), western blot (WB), and flow cytometry analysis collectively demonstrated that GCRV-II invaded Mo/Mφs and replicated in them. Additionally, we observed that GCRV-II induced different types (M1 and M2) of polarization of Mo/Mφs in multiple tissues, especially in the brain, head kidney, and intestine. To assess the impact of different types of polarization on GCRV-II replication, we recombinantly expressed and purified the intact cytokines CiIFN-γ2, CiIL-4/13A, and CiIL-4/13B and successfully induced M1 and M2 type polarization of macrophages using these cytokines through in vitro experiments. qRT-PCR, WB, and flow cytometry analyses showed that M2 macrophages had higher susceptibility to GCRV-II infection than other types of Mo/Mφs. In addition, we found GCRV-II induced apoptosis of Mo/Mφs to facilitate virus replication and dissemination and also detected the presence of GCRV-II virus in plasma. Collectively, our findings indicated that GCRV-II could invade immune cells Mo/Mφs and induce apoptosis and polarization of Mo/Mφs for efficient infection and dissemination, emphasizing the crucial role of Mo/Mφs as a vector for GCRV-II infection.IMPORTANCEType II grass carp reovirus (GCRV) is a prevalent viral strain and causes huge losses in aquaculture. However, the related dissemination pathway and mechanism remain largely unclear. Here, our study focused on phagocytic immune cells, monocytes/macrophages (Mo/Mφs) in blood and tissues, and explored whether GCRV-II can invade Mo/Mφs and replicate and disseminate via Mo/Mφs with their differentiated type M1 and M2 macrophages. Our findings demonstrated that GCRV-II infected Mo/Mφs and replicated in them. Furthermore, GCRV-II infection induces an increased number of M1 and M2 macrophages in grass carp tissues and a higher viral load in M2 macrophages. Furthermore, GCRV-II induced Mo/Mφs apoptosis to release viruses, eventually infecting more cells. Our study identified Mo/Mφs as crucial components in the pathway of GCRV-II dissemination and provides a solid foundation for the development of treatment strategies for GCRV-II infection.

Regulatory role of miRNAs in the human immune and inflammatory response during the infection of SARS-CoV-2 and other respiratory viruses: A comprehensive review

miRNAs are single-stranded ncRNAs that act as regulators of different human body processes. Several miRNAs have been noted to control the human immune and inflammatory response during severe acute respiratory infection syndrome (SARS-CoV-2) infection. Similarly, many miRNAs were upregulated and downregulated during different respiratory virus infections. Here, an attempt has been made to capture the regulatory role of miRNAs in the human immune and inflammatory response during the infection of SARS-CoV-2 and other respiratory viruses. Firstly, the role of miRNAs has been depicted in the human immune and inflammatory response during the infection of SARS-CoV-2. In this direction, several significant points have been discussed about SARS-CoV-2 infection, such as the role of miRNAs in human innate immune response; miRNAs and its regulation of granulocytes; the role of miRNAs in macrophage activation and polarisation; miRNAs and neutrophil extracellular trap formation; miRNA-related inflammatory response; and miRNAs association in adaptive immunity. Secondly, the miRNAs landscape has been depicted during human respiratory virus infections such as human coronavirus, respiratory syncytial virus, influenza virus, rhinovirus, and human metapneumovirus. The article will provide more understanding of the miRNA-controlled mechanism of the immune and inflammatory response during COVID-19, which will help more therapeutics discoveries to fight against the future pandemic.

Microglial Inflammatory Responses to SARS-CoV-2 Infection: A Comprehensive Review

Coronavirus disease 2019 (COVID-19) is primarily a respiratory disease causing a worldwide pandemic in the year of 2019. SARS-CoV-2 is an enveloped, positive-stranded RNA virus that could invade the host through spike protein and exhibits multi-organ effects. The Brain was considered to be a potential target for SARS-CoV-2 infection. Although neuropsychiatric symptoms and cognitive impairments were observed in COVID-19 patients even after recovery the mechanism of action is not well documented. In this review, the contribution of microglia in response to SARS-CoV-2 infection was discussed aiming to design a therapeutic regimen for the management of neuroinflammation and psycho-behavioral alterations. Priming of microglia facilitates the hyper-activation state when it interacts with SARS-CoV-2 known as the 'second hit'. Moreover, the microgliosis produces reactive free radicals and pro-inflammatory cytokines like IL-1β, IFN-γ, and IL-6 which ultimately contribute to a 'cytokine storm', thereby increasing the occurrence of cognitive and neurological dysfunction. It was reported that elevated CCL11 may be responsible for psychiatric disorders and ROS/RNS-induced oxidative stress could promote major depressive disorder (MDD) and phenotypic switching. Additionally, during SARS-CoV-2 infection microglia-CD8+ T cell interaction may have a significant role in neuronal cell death. This cytokine-mediated cellular cross-talking plays a crucial role in pro-inflammatory and anti-inflammatory balance within the COVID-19 patient's brain. Therefore, all these aspects will be taken into consideration for developing novel therapeutic strategies to combat SARS-CoV-2-induced neuroinflammation.

Pathogenicity and virulence of influenza

Influenza viruses, including four major types (A, B, C, and D), can cause mild-to-severe and lethal diseases in humans and animals. Influenza viruses evolve rapidly through antigenic drift (mutation) and shift (reassortment of the segmented viral genome). New variants, strains, and subtypes have emerged frequently, causing epidemic, zoonotic, and pandemic infections, despite currently available vaccines and antiviral drugs. In recent years, avian influenza viruses, such as H5 and H7 subtypes, have caused hundreds to thousands of zoonotic infections in humans with high case fatality rates. The likelihood of these animal influenza viruses acquiring airborne transmission in humans through viral evolution poses great concern for the next pandemic. Severe influenza viral disease is caused by both direct viral cytopathic effects and exacerbated host immune response against high viral loads. Studies have identified various mutations in viral genes that increase viral replication and transmission, alter tissue tropism or species specificity, and evade antivirals or pre-existing immunity. Significant progress has also been made in identifying and characterizing the host components that mediate antiviral responses, pro-viral functions, or immunopathogenesis following influenza viral infections. This review summarizes the current knowledge on viral determinants of influenza virulence and pathogenicity, protective and immunopathogenic aspects of host innate and adaptive immune responses, and antiviral and pro-viral roles of host factors and cellular signalling pathways. Understanding the molecular mechanisms of viral virulence factors and virus-host interactions is critical for the development of preventive and therapeutic measures against influenza diseases.

Hepatic macrophages play critical roles in the establishment and growth of hydatid cysts in the liver during Echinococcus granulosus sensu stricto infection

Cystic echinococcosis (CE) is a worldwide neglected zoonotic disease caused by infection with the larval stage of the tapeworm Echinococcus granulosus sensu lato (E. granulosus s.l.), which predominantly resides in the liver accompanied by mild inflammation. Macrophages constitute the main cellular component of the liver and play a central role in controlling the progression of inflammation and liver fibrosis. However, the role of hepatic macrophages in the establishment and growth of hydatid cysts in the liver during E. granulosus sensu stricto (E. granulosus s.s.) infection has not been fully elucidated. Here, we showed that CD68+ macrophages accumulated in pericystic areas of the liver and that the expression of CD163, a marker of anti-inflammatory macrophages, was more evident in active CE patients than in inactive CE patients. Moreover, in a mouse model of E. granulosus s.s. infection, the pool of hepatic macrophages expanded dramatically through the attraction of massive amounts of monocyte-derived macrophages (MoMFs) to the infection site. These infiltrating macrophages preferentially polarized toward an iNOS+ proinflammatory phenotype at the early stage and then toward a CD206+ anti-inflammatory phenotype at the late stage. Notably, the resident Kupffer cells (KCs) predominantly maintained an anti-inflammatory phenotype to favor persistent E. granulosus s.s. infection. In addition, depletion of hepatic macrophages promoted E. granulosus s.s. larval establishment and growth partially by inhibiting CD4+ T-cell recruitment and liver fibrosis. The above findings demonstrated that hepatic macrophages play a vital role in the progression of CE, contributing to a better understanding of the local inflammatory responses surrounding hydatid cysts and possibly facilitating the design of novel therapeutic approaches for CE.

Cholinergic Polarization of Human Macrophages

Macrophages serve as vital defenders, protecting the body by exhibiting remarkable cellular adaptability in response to invading pathogens and various stimuli. These cells express nicotinic acetylcholine receptors, with the α7-nAChR being extensively studied due to its involvement in activating the cholinergic anti-inflammatory pathway. Activation of this pathway plays a crucial role in suppressing macrophages' production of proinflammatory cytokines, thus mitigating excessive inflammation and maintaining host homeostasis. Macrophage polarization, which occurs in response to specific pathogens or insults, is a process that has received limited attention concerning the activation of the cholinergic anti-inflammatory pathway and the contributions of the α7-nAChR in this context. This review aims to present evidence highlighting how the cholinergic constituents in macrophages, led by the α7-nAChR, facilitate the polarization of macrophages towards anti-inflammatory phenotypes. Additionally, we explore the influence of viral infections on macrophage inflammatory phenotypes, taking into account cholinergic mechanisms. We also review the current understanding of macrophage polarization in response to these infections. Finally, we provide insights into the relatively unexplored partial duplication of the α7-nAChR, known as dup α7, which is emerging as a significant factor in macrophage polarization and inflammation scenarios.

Integrated Immunopeptidomic and Proteomic Analysis of COVID-19 lung biopsies

Introduction

Severe respiratory illness is the most prominent manifestation of patients infected with SARS-CoV-2, and yet the molecular mechanisms underlying severe lung disease in COVID-19 affected patients still require elucidation. Human leukocyte antigen class I (HLA-I) expression is crucial for antigen presentation and the host's response to SARS-CoV-2.

Methods

To gain insights into the immune response and molecular pathways involved in severe lung disease, we performed immunopeptidomic and proteomic analyses of lung tissues recovered at four COVID-19 autopsy and six non-COVID-19 transplants.

Results

We found signals of tissue injury and regeneration in lung fibroblast and alveolar type I/II cells, resulting in the production of highly immunogenic self-antigens within the lungs of COVID-19 patients. We also identified immune activation of the M2c macrophage as the primary source of HLA-I presentation and immunogenicity in this context. Additionally, we identified 28 lung signatures that can serve as early plasma markers for predicting infection and severe COVID-19 disease. These protein signatures were predominantly expressed in macrophages and epithelial cells and were associated with complement and coagulation cascades.

Discussion

Our findings emphasize the significant role of macrophage-mediated immunity in the development of severe lung disease in COVID-19 patients.

Porcine Macrophage Markers and Populations: An Update

Besides its importance as a livestock species, pig is increasingly being used as an animal model for biomedical research. Macrophages play critical roles in immunity to pathogens, tissue development, homeostasis and tissue repair. These cells are also primary targets for replication of viruses such as African swine fever virus, classical swine fever virus, and porcine respiratory and reproductive syndrome virus, which can cause huge economic losses to the pig industry. In this article, we review the current status of knowledge on porcine macrophages, starting by reviewing the markers available for their phenotypical characterization and following with the characteristics of the main macrophage populations described in different organs, as well as the effect of polarization conditions on their phenotype and function. We will also review available cell lines suitable for studies on the biology of porcine macrophages and their interaction with pathogens.

M1/M2 macrophages and their overlaps - myth or reality?

Macrophages represent heterogeneous cell population with important roles in defence mechanisms and in homoeostasis. Tissue macrophages from diverse anatomical locations adopt distinct activation states. M1 and M2 macrophages are two polarized forms of mononuclear phagocyte in vitro differentiation with distinct phenotypic patterns and functional properties, but in vivo, there is a wide range of different macrophage phenotypes in between depending on the microenvironment and natural signals they receive. In human infections, pathogens use different strategies to combat macrophages and these strategies include shaping the macrophage polarization towards one or another phenotype. Macrophages infiltrating the tumours can affect the patient's prognosis. M2 macrophages have been shown to promote tumour growth, while M1 macrophages provide both tumour-promoting and anti-tumour properties. In autoimmune diseases, both prolonged M1 activation, as well as altered M2 function can contribute to their onset and activity. In human atherosclerotic lesions, macrophages expressing both M1 and M2 profiles have been detected as one of the potential factors affecting occurrence of cardiovascular diseases. In allergic inflammation, T2 cytokines drive macrophage polarization towards M2 profiles, which promote airway inflammation and remodelling. M1 macrophages in transplantations seem to contribute to acute rejection, while M2 macrophages promote the fibrosis of the graft. The view of pro-inflammatory M1 macrophages and M2 macrophages suppressing inflammation seems to be an oversimplification because these cells exploit very high level of plasticity and represent a large scale of different immunophenotypes with overlapping properties. In this respect, it would be more precise to describe macrophages as M1-like and M2-like.

Macrophage-Specific Coxsackievirus and Adenovirus Receptor Deletion Enhances Macrophage M1 Polarity in CVB3-Induced Myocarditis

The coxsackievirus and adenovirus receptor (CAR) is very well known as an epithelial tight junction and cardiac intercalated disc protein; it mediates attachment and infection via the coxsackievirus B3 (CVB3) and type 5 adenovirus. Macrophages play important roles in early immunity during viral infections. However, the role of CAR in macrophages is not well studied in relation to CVB3 infection. In this study, the function of CAR was observed in the Raw264.7 mouse macrophage cell line. CAR expression was stimulated by treatment with lipopolysaccharide (LPS) and tumor necrosis factor-α (TNF-α). In thioglycollate-induced peritonitis, the peritoneal macrophage was activated and CAR expression was increased. The macrophage-specific CAR conditional knockout mice (KO) were generated from lysozyme Cre mice. The expression of inflammatory cytokine (IL-1β and TNF-α) was attenuated in the KO mice’s peritoneal macrophage after LPS treatment. In addition, the virus was not replicated in CAR-deleted macrophages. The organ virus replication was not significantly different in both wild-type (WT) and KO mice at days three and seven post-infection (p.i). However, the inflammatory M1 polarity genes (IL-1β, IL-6, TNF-α and MCP-1) were significantly increased, with increased rates of myocarditis in the heart of KO mice compared to those of WT mice. In contrast, type1 interferon (IFN-α and β) was significantly decreased in the heart of KO mice. Serum chemokine CXCL-11 was increased in the KO mice at day three p.i. compared to the WT mice. The attenuation of IFN-α and β in macrophage CAR deletion induced higher levels of CXCL-11 and more increased CD4 and CD8 T cells in KO mice hearts compared to those of WT mice at day seven p.i. These results demonstrate that macrophage-specific CAR deletion increased the macrophage M1 polarity and myocarditis in CVB3 infection. In addition, chemokine CXCL-11 expression was increased, and stimulated CD4 and CD8 T cell activity. Macrophage CAR may be important for the regulation of innate-immunity-induced local inflammation in CVB3 infection.

Inflammation and the Potential Implication of Macrophage-Microglia Polarization in Human ASD: An Overview

Autism spectrum disorder (ASD) is a heterogeneous collection of neurodevelopmental disorders, difficult to diagnose and currently lacking treatment options. The possibility of finding reliable biomarkers useful for early identification would offer the opportunity to intervene with treatment strategies to improve the life quality of ASD patients. To date, there are many recognized risk factors for the development of ASD, both genetic and non-genetic. Although genetic and epigenetic factors may play a critical role, the extent of their contribution to ASD risk is still under study. On the other hand, non-genetic risk factors include pollution, nutrition, infection, psychological states, and lifestyle, all together known as the exposome, which impacts the mother's and fetus's life, especially during pregnancy. Pathogenic and non-pathogenic maternal immune activation (MIA) and autoimmune diseases can cause various alterations in the fetal environment, also contributing to the etiology of ASD in offspring. Activation of monocytes, macrophages, mast cells and microglia and high production of pro-inflammatory cytokines are indeed the cause of neuroinflammation, and the latter is involved in ASD's onset and development. In this review, we focused on non-genetic risk factors, especially on the connection between inflammation, macrophage polarization and ASD syndrome, MIA, and the involvement of microglia.

Type 2 Immunity and Its Impact on COVID-19 Infection in the Airways

Type 2 immune responses are characterized by elevated type 2 cytokines and blood eosinophilia. Emerging evidence suggests that people with chronic type 2 inflammatory lung diseases are not particularly susceptible to SARS-CoV-2 infection. Intriguingly, recent in vitro, ex vivo research demonstrates type 2 cytokines, particularly IL-13, reduce the risk of SARS-CoV-2 infection in the airway epithelium. IL-13 treatment in airway epithelial cells followed by SARS-CoV-2 diminished viral entry, replication, spread, and cell death. IL-13 reduces the expression of the angiotensin-converting enzyme 2 (ACE2) receptor in the airway epithelium and transmembrane serine protease 2 (TMPRSS2), particularly in ciliated cells. It also alters the cellular composition toward a secretory-cell-rich phenotype reducing total ciliated cells and, thus, reducing viral tropism. IL-13 enhances Muc5ac mucin and glycocalyx secretion in the periciliary layer, which acts as a physical barrier to restrict virus attachment. Moreover, type 2 airway immune cells, such as M2 alveolar macrophages, CD4+ tissue-resident memory T cells, and innate lymphoid 2 cells, may also rescue type 2 airways from SARS-CoV-2-induced adverse effects. In this review, we discuss recent findings that demonstrate how type 2 immunity alters immune responses against SARS-CoV-2 and its consequences on COVID-19 pathogenesis.

Translatome analyses by bio-orthogonal non-canonical amino acid labeling reveal that MR1-activated MAIT cells induce an M1 phenotype and antiviral programming in antigen-presenting monocytes

MAIT cells are multifunctional innate-like effector cells recognizing bacterial-derived vitamin B metabolites presented by the non-polymorphic MHC class I related protein 1 (MR1). However, our understanding of MR1-mediated responses of MAIT cells upon their interaction with other immune cells is still incomplete. Here, we performed the first translatome study of primary human MAIT cells interacting with THP-1 monocytes in a bicellular system. We analyzed the interaction between MAIT and THP-1 cells in the presence of the activating 5-OP-RU or the inhibitory Ac-6-FP MR1-ligand. Using bio-orthogonal non-canonical amino acid tagging (BONCAT) we were able to enrich selectively those proteins that were newly translated during MR1-dependent cellular interaction. Subsequently, newly translated proteins were measured cell-type-specifically by ultrasensitive proteomics to decipher the coinciding immune responses in both cell types. This strategy identified over 2,000 MAIT and 3,000 THP-1 active protein translations following MR1 ligand stimulations. Translation in both cell types was found to be increased by 5-OP-RU, which correlated with their conjugation frequency and CD3 polarization at MAIT cell immunological synapses in the presence of 5-OP-RU. In contrast, Ac-6-FP only regulated a few protein translations, including GSK3B, indicating an anergic phenotype. In addition to known effector responses, 5-OP-RU-induced protein translations uncovered type I and type II Interferon-driven protein expression profiles in both MAIT and THP-1 cells. Interestingly, the translatome of THP-1 cells suggested that activated MAIT cells can impact M1/M2 polarization in these cells. Indeed, gene and surface expression of CXCL10, IL-1β, CD80, and CD206 confirmed an M1-like phenotype of macrophages being induced in the presence of 5-OP-RU-activated MAIT cells. Furthermore, we validated that the Interferon-driven translatome was accompanied by the induction of an antiviral phenotype in THP-1 cells, which were found able to suppress viral replication following conjugation with MR1-activated MAIT cells. In conclusion, BONCAT translatomics extended our knowledge of MAIT cell immune responses at the protein level and discovered that MR1-activated MAIT cells are sufficient to induce M1 polarization and an anti-viral program of macrophages.

Macrophages Phenotype Regulated by IL-6 Are Associated with the Prognosis of Platinum-Resistant Serous Ovarian Cancer: Integrated Analysis of Clinical Trial and Omics

Background

The treatment of platinum-resistant recurrent ovarian cancer (PROC) is a clinical challenge and a hot topic. Tumor microenvironment (TME) as a key factor promoting ovarian cancer progression. Macrophage is a component of TME, and it has been reported that macrophage phenotype is related to the development of PROC. However, the mechanism underlying macrophage polarization and whether macrophage phenotype can be used as a prognostic indicator of PROC remains unclear.

Methods

We used ESTIMATE to calculate the number of immune and stromal components in high-grade serous ovarian cancer (HGSOC) cases from The Cancer Genome Atlas database. The differential expression genes (DEGs) were analyzed via protein-protein interaction network, Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) analysis to reveal major pathways of DEGs. CD80 was selected for survival analysis. IL-6 was selected for gene set enrichment analysis (GSEA). A subsequent cohort study was performed to confirm the correlation of IL-6 expression with macrophage phenotype in peripheral blood and to explore the clinical utility of macrophage phenotype for the prognosis of PROC patients.

Results

A total of 993 intersecting genes were identified as candidates for further survival analysis. Further analysis revealed that CD80 expression was positively correlated with the survival of HGSOC patients. The results of GO and KEGG analysis suggested that macrophage polarization could be regulated via chemokine pathway and cytokine-cytokine receptor interaction. GSEA showed that the genes were mainly enriched in IL-6-STAT-3. Correlation analysis for the proportion of tumor infiltration macrophages revealed that M2 was correlated with IL-6. The results of a cohort study demonstrated that the regulation of macrophage phenotype by IL-6 is bidirectional. The high M1% was a protective factor for progression-free survival.

Conclusion

Thus, the macrophage phenotype is a prognostic indicator in PROC patients, possibly via a hyperactive IL-6-related pathway, providing an additional clue for the therapeutic intervention of PROC.