IL-2 is the master-regulator cytokine for T cell dependent responses and is crucial for proliferation and survival of T cells. However, IL-2-based treatments remained marginal, in part due to short ...half-life. Thus, we aimed to extend IL-2 half-life by flanking the IL-2 core with sequences derived from the extensively glycosylated hinge region of the NCR2 receptor. We termed this modified IL-2: "S2A". Importantly, S2A blood half-life was extended 14-fold compared to the clinical grade IL-2, Proleukin. Low doses inoculation of S2A significantly enhanced induction of Tregs (CD4
Regulatory T cells) in vivo, as compared to Proleukin, while both S2A and Proleukin induced low levels of CD8
T cells. In a B16 metastatic melanoma model, S2A treatment was unable to reduce the metastatic capacity of B16 melanoma, while enhancing induction and recruitment of Tregs, compared to Proleukin. Conversely, in two autoimmune models, rheumatoid arthritis and DSS-induced colitis, S2A treatment significantly reduced the progression of disease compared to Proleukin. Our results suggest new avenues for generating long-acting IL-2 for long-standing treatment and a new technique for manipulating short-life proteins for clinical and research uses.
Abstract Toll-like receptor 7 (TLR7) known to recognize guanidine-rich ssRNA has been shown to mount vital host defense mechanism against many viruses including flaviviruses. Signal transduction ...through TLR7 has been shown to produce type-1 interferon and proinflammatory mediators, thereby initiating essential innate immune response against ssRNA viruses in hosts. Systemic and brain specific TLR7 knock-down mice (TLR7KD ) were generated using vivo-morpholinos. These mice were then subcutaneously challenged with lethal dose of JEV (GP78 strain) and were subsequently analyzed for survival. Significant difference in susceptibility to JEV between wild-type and systemic TLR7KD mice was observed whereas, no difference in susceptibility to JEV infection was seen in brain-specific TLR7KD mice. Significant decreases in IFN-α and antiviral proteins were also observed in both TLR7KD mice along with increased viral loads in their brain. Owing to increased viral load, increases in levels of various proinflammatory cyto/chemokines, increased microglial activation and infiltration of peripheral immune cells in brain of TLR7KD mice were also observed. Immunocytochemistry and RNA co-immunoprecipitation performed with JEV-infected N2a or HT22 cells indicated endosomal localization and confirmed interaction between JEV ssRNA with TLR7. Treatment of mice with imiquimod, a TLR7 agonist, prior to JEV infection resulted in their increased survival. Overall, our results suggest that the TLR7 response following JEV infection promotes type-1 interferon production and generation of antiviral state which might contribute to protective effect in systemic infection.
Harnessing the immune-system to eradicate cancer is becoming a reality in recent years. Engineered immune cells, such as chimeric antigen receptor (CAR) T cells, are facing the danger of an overt ...life-threatening immune response due to the ON-target OFF-tumor cytotoxicity and Cytokine Release Syndrome. We therefore developed synthetic promoters for regulation of gene expression under the control of inflammation and Hypoxia-induced signals that are associated with the tumor microenvironment (TME). We termed this methodology as chimeric-antigen-receptor-tumor-induced-vector (CARTIV). For proof of concept, we studied synthetic promoters based on promoter-responsive elements (PREs) of IFNγ, TNFα and hypoxia; triple PRE-based CARTIV promoter manifested a synergistic activity in cell-lines and potent activation in human primary T-cells. CARTIV platform can improve safety of CAR T-cells or other engineered immune-cells, providing TME-focused activity and opening a therapeutic window for many tumor-associated antigens that are also expressed by non-tumor healthy tissues.
Proliferating cell nuclear antigen (PCNA) is considered as a hub protein and is a key regulator of DNA replication, repair, cell cycle control, and apoptosis. PCNA is overexpressed in many cancer ...types, and PCNA overexpression is correlated with cancer virulence. Membrane-associated PCNA is a ligand for the NKp44 (NCR2) innate immune receptor. The purpose of this study was to characterize the PCNA-binding site within NKp44. We have identified NKp44-derived linear peptide (pep8), which can specifically interact with PCNA and partly block the NKp44-PCNA interaction. We then tested whether NKp44-derived pep8 (NKp44-pep8) fused to cell-penetrating peptides (CPPs) can be employed for targeting the intracellular PCNA for the purpose of anticancer therapy. Treatment of tumor cells with NKp44-pep8, fused to R11-NLS cell-penetrating peptide (R11-NLS-pep8), reduced cell viability and promoted cell death, in various murine and human cancer cell lines. Administration of R11-NLS-pep8 to tumor-bearing mice suppressed tumor growth in the 4T1 breast cancer and the B16 melanoma
models. We therefore identified the NKp44 binding site to PCNA and further developed an NKp44-peptide-based agent that can inhibit tumor growth through interfering with the function of intracellular PCNA in the tumor cell.
Despite of remarkable progress made in the head and neck cancer (HNC) therapy, the survival rate of this metastatic disease remain low. Tailoring the appropriate therapy to patients is a major ...challenge and highlights the unmet need to have a good preclinical model that will predict clinical response. Hence, we developed an accurate and time efficient drug screening method of tumor
analysis (TEVA) system, which can predict patient-specific drug responses. In this study, we generated six patient derived xenografts (PDXs) which were utilized for TEVA. Briefly, PDXs were cut into 2 × 2 × 2 mm
explants and treated with clinically relevant drugs for 24 h. Tumor cell proliferation and death were evaluated by immunohistochemistry and TEVA score was calculated.
and
drug efficacy studies were performed on four PDXs and three drugs side-by-side to explore correlation between TEVA and PDX treatment
. Efficacy of drug combinations was also ventured. Optimization of the culture timings dictated 24 h to be the time frame to detect drug responses and drug penetrates 2 × 2 × 2 mm
explants as signaling pathways were significantly altered. Tumor responses to drugs in TEVA, significantly corresponds with the drug efficacy in mice. Overall, this low cost, robust, relatively simple and efficient 3D tissue-based method, employing material from one PDX, can bypass the necessity of drug validation in immune-incompetent PDX-bearing mice. Our data provides a potential rationale for utilizing TEVA to predict tumor response to targeted and chemo therapies when multiple targets are proposed.
The Ebola Virus (EBOV) glycoprotein (GP) sterically shields cell-membrane ligands to immune receptors such as human leukocyte antigen class-1 (HLA-I) and MHC class I polypeptide-related sequence A ...(MICA), thus mediating immunity evasion. It was suggested that the abundant N-glycosylation of the EBOV-GP is involved in this steric shielding. We aimed to characterize (i) the GP N-glycosylation sites contributing to the shielding, and (ii) the effect of mutating these sites on immune subversion by the EBOV-GP. The two highly glycosylated domains of GP are the mucin-like domain (MLD) and the glycan cap domain (GCD) with three and six N-glycosylation sites, respectively. We mutated the N-glycosylation sites either in MLD or in GCD or in both domains. We showed that the glycosylation sites in both the MLD and GCD domains contribute to the steric shielding. This was shown for the steric shielding of either HLA-I or MICA. We then employed the fluorescence resonance energy transfer (FRET) method to measure the effect of N-glycosylation site removal on the distance in the cell membrane between the EBOV-GP and HLA-I (HLA.A
0201 allele). We recorded high FRET values for the interaction of CFP-fused HLA.A
0201 and YFP-fused EBOV-GP, demonstrating the very close distance (<10 nm) between these two proteins on the cell membrane of GP-expressing cells. The co-localization of HLA-I and Ebola GP was unaffected by the disruption of steric shielding, as the removal of N-glycosylation sites on Ebola GP revealed similar FRET values with HLA-I. However, these mutations directed to N-glycosylation sites had restored immune cell function otherwise impaired due to steric shielding over immune cell ligands by WT Ebola GP. Overall, we showed that the GP-mediated steric shielding aimed to impair immune function is facilitated by the N-glycans protruding from its MLD and GCD domains, but these N-glycans are not controlling the close distance between GP and its shielded proteins.
The natural killer (NK) cell activating receptor NKp46/NCR1 plays a critical role in elimination of virus-infected and tumor cells. The
gene can be transcribed into five different splice variants, ...but the functional importance and physiological distribution of NKp46 isoforms are not yet fully understood. Here, we shed light on differential expression of NKp46 splice variants in viral respiratory tract infections and their functional difference at the cellular level. NKp46 was the most predominantly expressed natural cytotoxicity receptor in the nasal lavage of patients infected with four respiratory viruses: respiratory syncytia virus, adenovirus, human metapneumovirus, or influenza A. Expression of NKp30 was far lower and NKp44 was absent in all patients. Domain 1-negative NKp46 splice variants (i.e., NKp46 isoform d) were the predominantly expressed isoform in nasal lavage following viral infections. Using our unique anti-NKp46 mAb, D2-9A5, which recognizes the D2 extracellular domain, and a commercial anti-NKp46 mAb, 9E2, which recognizes D1 domain, allowed us to identify a small subset of NKp46 D1-negative splice variant-expressing cells within cultured human primary NK cells. This NKp46 D1-negative subset also showed higher degranulation efficiency in term of CD107a surface expression. NK-92 cell lines expressing NKp46 D1-negative and NKp46 D1-positive splice variants also showed functional differences when interacting with targets. A NKp46 D1-negative isoform-expressing NK-92 cell line showed enhanced degranulation activity. To our knowledge, we provide the first evidence showing the physiological distribution and functional importance of human NKp46 splice variants under pathological conditions.
Japanese encephalitis virus (JEV), a single‐stranded RNA (ssRNA) virus, is the leading cause of encephalitis in Asia. Microglial activation is one of the key events in JEV‐induced neuroinflammation. ...Although the various microRNAs (miRNAs) has been shown to regulate microglia activation during pathological conditions including neuroviral infections, till date, the involvement of miRNAs in JEV infection has not been evaluated. Hence, we sought to evaluate the possible role of miRNAs in mediating JEV‐induced microglia activation. Initial screening revealed significant up‐regulation of miR‐29b in JEV‐infected mouse microglial cell line (BV‐2) and primary microglial cells. Furthermore, using bioinformatics tools, we identified tumor necrosis factor alpha‐induced protein 3, a negative regulator of nuclear factor‐kappa B signaling as a potential target of miR‐29b. Interestingly, in vitro knockdown of miR‐29b resulted in significant over‐expression of tumor necrosis factor alpha‐induced protein 3, and subsequent decrease in nuclear translocation of pNF‐κB. JEV infection in BV‐2 cell line elevated inducible nitric oxide synthase, cyclooxygenase‐2, and pro‐inflammatory cytokine expression levels, which diminished after miR‐29b knockdown. Collectively, our study demonstrates involvement of miR‐29b in regulating JEV‐ induced microglial activation.
miR‐29b regulates Japanese Encephalitis Virus (JEV)‐induced microglia activation via inhibition of the anti‐inflammatory proteinTNFAIP3, which results in sustained activation of NF‐kB. Sustained NF‐?Bactivation further results in augmented secretion of pro‐inflammatory cytokines and induction of inflammatory mediators (iNOS and Cox‐2).
miR‐29b regulates Japanese Encephalitis Virus (JEV)‐induced microglia activation via inhibition of the anti‐inflammatory proteinTNFAIP3, which results in sustained activation of NF‐kB. Sustained NF‐?Bactivation further results in augmented secretion of pro‐inflammatory cytokines and induction of inflammatory mediators (iNOS and Cox‐2).
MicroRNAs (miRNAs) are single-stranded small RNA molecules that regulate various cellular processes. miRNA 155 (miR-155) regulates various aspects of innate and adaptive immune responses and plays a ...key role in various viral infections and the resulting neuroinflammation. The present study evaluated the involvement of miR-155 in modulating Japanese encephalitis virus (JEV)-induced neuroinflammation. We observed that miR-155 expression was upregulated during JEV infection of mouse primary microglia, the BV-2 microglia cell line, and in both mouse and human brains. In vitro and in vivo knockdown of miR-155 minimized JEV-induced inflammatory responses. In the present study, we confirmed targeting of the Src homology 2-containing inositol phosphatase 1 (SHIP1) 3' untranslated region (UTR) by miR-155 in the context of JEV infection. Inhibition of SHIP1 by miR-155 resulted in higher beta interferon (IFN-β) and proinflammatory cytokine production through activation of TANK-binding kinase 1 (TBK-1). Based on these observations, we conclude that miR-155 modulates the neuroinflammatory response during JEV infection via negative regulation of SHIP1 expression. Thus, modulation of miR-155 could be a novel strategy to regulate JEV-induced neuroinflammation.
Japanese encephalitis virus (JEV), a member of the family Flaviviridae that causes Japanese encephalitis (JE), is the most common mosquito-borne encephalitis virus in the Asia-Pacific region. The disease is feared, as currently there are no specific antiviral drugs available. JEV targets the central nervous system, leading to high mortality and neurological and psychiatric sequelae in some of those who survive. The level of inflammation correlates well with the clinical outcome in patients. Recently, microRNA (miRNA), a single-stranded noncoding RNA, has been implicated in various brain disorders. The present study investigates the role of miRNA in JEV-induced neuroinflammation. Our results show that miRNA 155 (miR-155) targets the Src homology 2-containing inositol phosphatase 1 (SHIP1) protein and promotes inflammation by regulating the NF-κB pathway, increasing the expression of various proinflammatory cytokines and the antiviral response. Thus, miR-155 is a potential therapeutic target to develop antivirals in JE and other brain disorders where inflammation plays a significant role in disease progression.
The natural cytotoxicity receptors (NCRs; NKp30, NKp44, and NKp46) were first defined as activating receptors on human NK cells that are important in recognition of and response to tumors. A flurry ...of recent research, however, has revealed that differential splicing can occur during transcription of each of the NCR genes, resulting in some transcripts that encode receptor isoforms with inhibitory functions. These alternative transcripts can arise in certain tissue microenvironments and appear to be induced by cytokines. Evidence indicates that some of the inhibitory NCRs are triggered by specific ligands, such as the interaction of the inhibitory isoform of NKp44 with PCNA on the surface of tumor cells. Here, we review the different NCR splice variants, cytokines that modulate their expression, their functional impacts on innate immune cells, and their differential expression in the contexts of cancer, pregnancy, and infections. The recent discovery of these inhibitory NCR isoforms has revealed novel innate immune checkpoints, many of which still lack defined ligands and clear mechanisms driving their expression. These NCR checkpoint pathways offer exciting potential therapeutic targets to manipulate innate immune functions under defined pathological conditions, such as cancer, pregnancy disorders, and pathogen exposure.
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