scholarly journals Long Non-coding RNAs RN7SK and GAS5 Regulate Macrophage Polarization and Innate Immune Responses

2020 ◽  
Vol 11 ◽  
Author(s):  
Imran Ahmad ◽  
Araceli Valverde ◽  
Raza Ali Naqvi ◽  
Afsar R. Naqvi

Macrophages (Mφ) are immune cells that exhibit remarkable functional plasticity. Identification of novel endogenous factors that can regulate plasticity and innate immune functions of Mφ will unravel new strategies to curb immune-related diseases. Long non-coding RNAs (lncRNAs) are a class of endogenous, non-protein coding, regulatory RNAs that are increasingly being associated with various cellular functions and diseases. Despite their ubiquity and abundance, lncRNA-mediated epigenetic regulation of Mφ polarization and innate immune functions is poorly studied. This study elucidates the regulatory role of lncRNAs in monocyte to Mφ differentiation, M1/M2 dichotomy and innate immune responses. Expression profiling of eighty-eight lncRNAs in monocytes and in vitro differentiated M2 Mφ identified seventeen differentially expressed lncRNAs. Based on fold-change and significance, we selected four differentially expressed lncRNAs viz., RN7SK, GAS5, IPW, and ZFAS1 to evaluate their functional impact. LncRNA knockdown was performed on day 3 M2 Mφ and the impact on polarization was assessed on day 7 by surface marker analysis. Knockdown of RN7SK and GAS5 showed downregulation of M2 surface markers (CD163, CD206, or Dectin) and concomitant increase in M1 markers (MHC II or CD23). RN7SK or GAS5 knockdown showed no significant impact on CD163, CD206, or CD23 transcripts. M1/M2 markers were not impacted by IPW or ZFAS1 knockdown. Functional regulation of antigen uptake/processing and phagocytosis, two central innate immune pathways, by candidate lncRNA was assessed in M1/M2 Mφ. Compared to scramble, enhanced antigen uptake and processing were observed in both M1/M2 Mφ transfected with siRNA targeting GAS5 and RN7SK but not IPW and ZFAS1. In addition, knockdown of RN7SK significantly augmented uptake of labelled E. coli in vitro by M1/M2 Mφ, while no significant difference was in GAS5 silencing cells. Together, our results highlight the instrumental role of lncRNA (RN7SK and GAS5)-mediated epigenetic regulation of macrophage differentiation, polarization, and innate immune functions.

2021 ◽  
Vol 12 ◽  
Author(s):  
Yaoyao Xia ◽  
Yikun Li ◽  
Xiaoyan Wu ◽  
Qingzhuo Zhang ◽  
Siyuan Chen ◽  
...  

Iron fine-tunes innate immune responses, including macrophage inflammation. In this review, we summarize the current understanding about the iron in dictating macrophage polarization. Mechanistically, iron orchestrates macrophage polarization through several aspects, including cellular signaling, cellular metabolism, and epigenetic regulation. Therefore, iron modulates the development and progression of multiple macrophage-associated diseases, such as cancer, atherosclerosis, and liver diseases. Collectively, this review highlights the crucial role of iron for macrophage polarization, and indicates the potential application of iron supplementation as an adjuvant therapy in different inflammatory disorders relative to the balance of macrophage polarization.


2020 ◽  
Author(s):  
Srinivasu Mudalagiriyappa ◽  
Jaishree Sharma ◽  
Hazem F. M. Abdelaal ◽  
Thomas C. Kelly ◽  
Woosuk Choi ◽  
...  

AbstractNon-Tuberculous Mycobacteria (NTM) are ubiquitous in nature, present in soil and water, and cause primary leading to disseminated infections in immunocompromised individuals. NTM infections are surging in recent years due to an increase in an immune-suppressed population, medical interventions, and patients with underlying lung diseases. Host regulators of innate immune responses, frontiers for controlling infections and dissemination, are poorly defined during NTM infections. Here, we describe the role of CBLB, an E3-ubiquitin ligase, for innate immune responses and disease progression in a mouse model of NTM infection under compromised T-cell immunity. We found that CBLB thwarted NTM growth and dissemination in a time- and infection route- dependent manner. Mechanistically, we uncovered defects in many innate immune cells in the absence of Cblb, including poor responses of NK cells, inflammatory monocytes, and conventional dendritic cells. Strikingly, Cblb-deficient macrophages were competent to control NTM growth in vitro. Histopathology suggested the lack of early formation of granulomatous inflammation in the absence of CBLB. Collectively, CBLB is essential to mount productive innate immune responses and help prevent the dissemination during an NTM infection under T-cell deficiency.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1274-1274
Author(s):  
Gernot Schabbauer ◽  
Nikolina Papac-Milicevic ◽  
Pavel Uhrin ◽  
Bernd Binder

Abstract Sepsis is still a major burden for the society with a high incidence of morbidity and mortality each year. Molecular mechanisms underlying the systemic inflammatory response syndrome (SIRS) associated with sepsis are still ill defined and most therapies developed to target the acute inflammatory component of the disease are insufficent. Recently the role of nuclear receptors (NRs) in transcriptional regulation of inflammatory processes became a major topic of interest. Nuclear receptors, such as the peroxisome proliferators-activated receptors (PPARs), have been found to exert anti-inflammatory properties by interfering with the NFkB pathway. We are interested in the nuclear envelope protein, interferon stimulated gene 12 (ISG12), which directly interacts with NRs. ISG12 is a co-factor stimulating nuclear export of NRs, thereby reducing the anti-inflammatory potential of NRs such as PPARg or NR4A1. To examine the role of ISG12 in acute inflammation we generated ISG12 deficient mice. We can demonstrate by reverse genetics in ISG12 deficient mice that lack of ISG12 is beneficial in experimental sepsis and endotoxemia. Furthermore we can show that several acute inflammatory parameters, such as systemic IL6 cytokine levels, are downregulated in septic ISG12-/- animals. Consistently, similar results could be obtained in in vitro experiments in peritoneal macrophages derived from ISG12 deficient mice. In contrast, mice deficient for the nuclear receptor NR4A1 exhibited an exacerbated innate immune response and showed a significantly higher mortality after lethal septic challenge. This dramatic phenotype could be restored in ISG12/NR4A1 double deficient mice. We conclude from our data in vitro and in vivo that ISG12 is a novel modulator of innate immune responses regulating anti-inflammatory nuclear receptors such as NR4A1.


2021 ◽  
Author(s):  
Fabrice Cognasse ◽  
Kathryn Hally ◽  
Sebastien Fauteux-Daniel ◽  
Marie-Ange Eyraud ◽  
Charles-Antoine Arthaud ◽  
...  

AbstractAside from their canonical role in hemostasis, it is increasingly recognized that platelets have inflammatory functions and can regulate both adaptive and innate immune responses. The main topic this review aims to cover is the proinflammatory effects and side effects of platelet transfusion. Platelets prepared for transfusion are subject to stress injury upon collection, preparation, and storage. With these types of stress, they undergo morphologic, metabolic, and functional modulations which are likely to induce platelet activation and the release of biological response modifiers (BRMs). As a consequence, platelet concentrates (PCs) accumulate BRMs during processing and storage, and these BRMs are ultimately transfused alongside platelets. It has been shown that BRMs present in PCs can induce immune responses and posttransfusion reactions in the transfusion recipient. Several recent reports within the transfusion literature have investigated the concept of platelets as immune cells. Nevertheless, current and future investigations will face the challenge of encompassing the immunological role of platelets in the scope of transfusion.


Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7461
Author(s):  
Claire K. Holley ◽  
Edward Cedrone ◽  
Duncan Donohue ◽  
Barry W. Neun ◽  
Daniela Verthelyi ◽  
...  

Understanding, predicting, and minimizing the immunogenicity of peptide-based therapeutics are of paramount importance for ensuring the safety and efficacy of these products. The so-called anti-drug antibodies (ADA) may have various clinical consequences, including but not limited to the alteration in the product’s distribution, biological activity, and clearance profiles. The immunogenicity of biotherapeutics can be influenced by immunostimulation triggered by the presence of innate immune response modulating impurities (IIRMIs) inadvertently introduced during the manufacturing process. Herein, we evaluate the applicability of several in vitro assays (i.e., complement activation, leukocyte proliferation, and cytokine secretion) for the screening of innate immune responses induced by ten common IIRMIs (Bacillus subtilis flagellin, FSL-1, zymosan, ODN2006, poly(I:C) HMW, poly(I:C) LMW, CLO75, MDP, ODN2216, and Escherichia coli O111:B4 LPS), and a model biotherapeutic Forteo™ (teriparatide). Our study identifies cytokine secretion from healthy human donor peripheral blood mononuclear cells (PBMC) as a sensitive method for the in vitro monitoring of innate immune responses to individual IIRMIs and teriparatide (TP). We identify signature cytokines, evaluate both broad and narrow multiplex cytokine panels, and discuss how the assay logistics influence the performance of this in vitro assay.


2020 ◽  
Author(s):  
Quentin Marquant ◽  
Daphné Laubreton ◽  
Carole Drajac ◽  
Elliot Mathieu ◽  
Edwige Bouguyon ◽  
...  

AbstractThe microbiota contributes to shaping efficient and safe immune defenses in the gut. However, little is known about the role of the microbiota in the education of pulmonary innate immune responses. Here, we tested whether the endogenous microbiota can modulate reactivity of pulmonary tissue to pathogen stimuli by comparing the response of specific pathogen-free (SPF) and germ-free (GF) mice. Using SPF and GF mice intranasally exposed to lipopolysaccharide (LPS), a component of Gram-negative bacteria, we observed earlier and greater inflammation in the pulmonary compartment of GF mice than that of SPF mice. Toll-like receptor 4 (TLR4) was more abundantly expressed in the lungs of GF mice than those of SPF mice at steady state, which could predispose the innate immunity of GF mice to strongly react to environmental stimuli. Lung explants were stimulated with different TLR agonists or infected with the human airways pathogen, respiratory syncytial virus (RSV), resulting in greater inflammation under almost all conditions for the GF explants. Finally, alveolar macrophages (AM) from GF mice presented a higher innate immune response upon RSV infection than those of SPF mice. Overall, these data suggest that the presence of microbiota in SPF mice induced a process of innate immune tolerance in the lungs by a mechanism which remains to be elucidated. Our study represents a step forward to establishing the link between the microbiota and the immune reactivity of the lungs.Plain Language summaryMicrobiota represents an important partner of immunologic system at the interface between immune cells and epithelium. It is well known, notably in the gut, that the microbiota contributes in shaping efficient and safe defenses. However, little is known about the role of the microbiota in the education of pulmonary innate immune responses. In this study, we postulate that endogenous microbiota could dampen an excessive reactivity of pulmonary tissue to external stimuli. Thus, we sought to study the innate immune reaction switched on by viral or bacterial ligands in respiratory tract cells coming from mice with or without microbiota (germ-free condition, GF). Altogether, our results show a higher inflammatory reaction in GF condition. This study represents a step forward to better establish the link between the microbiota and the reactivity of the lung tissue. Not only these data demonstrate that the microbiota educates the pulmonary innate immune system, but also contributes the emerging concept of using respiratory commensal bacteria as potential next-generation probiotics to prevent susceptibility to respiratory diseases.


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