V. Mysore et al. (may 2022)
The Journal of experimental medicine 219 5
Monocytes transition to macrophages within the inflamed vasculature via monocyte CCR2 and endothelial TNFR2.
Monocytes undergo phenotypic and functional changes in response to inflammatory cues,but the molecular signals that drive different monocyte states remain largely undefined. We show that monocytes acquire macrophage markers upon glomerulonephritis and may be derived from CCR2+CX3CR1+ double-positive monocytes,which are preferentially recruited,dwell within glomerular capillaries,and acquire proinflammatory characteristics in the nephritic kidney. Mechanistically,the transition to immature macrophages begins within the vasculature and relies on CCR2 in circulating cells and TNFR2 in parenchymal cells,findings that are recapitulated in vitro with monocytes cocultured with TNF-TNFR2-activated endothelial cells generating CCR2 ligands. Single-cell RNA sequencing of cocultures defines a CCR2-dependent monocyte differentiation path associated with the acquisition of immune effector functions and generation of CCR2 ligands. Immature macrophages are detected in the urine of lupus nephritis patients,and their frequency correlates with clinical disease. In conclusion,CCR2-dependent functional specialization of monocytes into macrophages begins within the TNF-TNFR2-activated vasculature and may establish a CCR2-based autocrine,feed-forward loop that amplifies renal inflammation.
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C. Mirabelli et al. (apr 2022)
mBio 13 2 e0017522
Human Norovirus Triggers Primary B Cell Immune Activation In Vitro.
Human norovirus (HNoV) is a global health and socioeconomic burden,estimated to infect every individual at least five times during their lifetime. The underlying mechanism for the potential lack of long-term immune protection from HNoV infections is not understood and prompted us to investigate HNoV susceptibility of primary human B cells and its functional impact. Primary B cells isolated from whole blood were infected with HNoV-positive stool samples and harvested at 3??days postinfection (dpi) to assess the viral RNA yield by reverse transcriptase quantitative PCR (RT-qPCR). A 3- to 18-fold increase in the HNoV RNA yield was observed in 50 to 60% of donors. Infection was further confirmed in B cells derived from splenic and lymph node biopsy specimens. Next,we characterized infection of whole-blood-derived B cells by flow cytometry in specific functional B cell subsets (naive CD27- IgD+,memory-switched CD27+ IgD-,memory-unswitched CD27+ IgD+,and double-negative CD27- IgD- cells). While the susceptibilities of the subsets were similar,changes in the B cell subset distribution upon infection were observed,which were also noted after treatment with HNoV virus-like particles and the predicted recombinant NS1 protein. Importantly,primary B cell stimulation with the predicted recombinant NS1 protein triggered B cell activation and induced metabolic changes. These data demonstrate that primary B cells are susceptible to HNoV infection and suggest that the NS1 protein can alter B cell activation and metabolism in vitro,which could have implications for viral pathogenesis and immune responses in vivo. IMPORTANCE Human norovirus (HNoV) is the most prevalent causative agent of gastroenteritis worldwide. Infection results in a self-limiting disease that can become chronic and severe in the immunocompromised,the elderly,and infants. There are currently no approved therapeutic and preventative strategies to limit the health and socioeconomic burdens associated with HNoV infections. Moreover,HNoV does not elicit lifelong immunity as repeat infections are common,presenting a challenge for vaccine development. Given the importance of B cells for humoral immunity,we investigated the susceptibility and impact of HNoV infection on human B cells. We found that HNoV replicates in human primary B cells derived from blood,spleen,and lymph node specimens,while the nonstructural protein NS1 can activate B cells. Because of the secreted nature of NS1,we put forward the hypothesis that HNoV infection can modulate bystander B cell function with potential impacts on systemic immune responses.
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K. Joannou et al. (may 2022)
Journal of immunology (Baltimore,Md. : 1950) 208 9 2131--2140
Thymocyte Maturation and Emigration in Adult Mice.
Several unique waves of ?? T cells are generated solely in the fetal/neonatal thymus,whereas additional ?? T cell subsets are generated in adults. One intriguing feature of ?? T cell development is the coordination of differentiation and acquisition of effector function within the fetal thymus; however,it is less clear whether this paradigm holds true in adult animals. In this study,we investigated the relationship between maturation and thymic export of adult-derived ?? thymocytes in mice. In the Rag2pGFP model,immature (CD24+) ?? thymocytes expressed high levels of GFP whereas only a minority of mature (CD24-) ?? thymocytes were GFP+ Similarly,most peripheral GFP+ ?? T cells were immature. Analysis of ?? recent thymic emigrants (RTEs) indicated that most ?? T cell RTEs were CD24+ and GFP+,and adoptive transfer experiments demonstrated that immature ?? thymocytes can mature outside the thymus. Mature ?? T cells largely did not recirculate to the thymus from the periphery; rather,a population of mature ?? thymocytes that produced IFN-? or IL-17 remained resident in the thymus for at least 60 d. These data support the existence of two populations of ?? T cell RTEs in adult mice: a majority subset that is immature and matures in the periphery after thymic emigration,and a minority subset that completes maturation within the thymus prior to emigration. Additionally,we identified a heterogeneous population of resident ?? thymocytes of unknown functional importance. Collectively,these data shed light on the generation of the ?? T cell compartment in adult mice.
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D. B. Hoelzinger et al. (jun 2022)
Blood advances 6 11 3458--3471
Extracellular vesicle proteomic analysis leads to the discovery of HDGF as a new factor in multiple myeloma biology.
Identifying factors secreted by multiple myeloma (MM) cells that may contribute to MM tumor biology and progression is of the utmost importance. In this study,hepatoma-derived growth factor (HDGF) was identified as a protein present in extracellular vesicles (EVs) released from human MM cell lines (HMCLs). Investigation of the role of HDGF in MM cell biology revealed lower proliferation of HMCLs following HDGF knockdown and AKT phosphorylation following the addition of exogenous HDGF. Metabolic analysis demonstrated that HDGF enhances the already high glycolytic levels of HMCLs and significantly lowers mitochondrial respiration,indicating that HDGF may play a role in myeloma cell survival and/or act in a paracrine manner on cells in the bone marrow (BM) tumor microenvironment (ME). Indeed,HDGF polarizes macrophages to an M1-like phenotype and phenotypically alters na{\{i}}ve CD14+ monocytes to resemble myeloid-derived suppressor cells which are functionally suppressive. In summary HDGF is a novel factor in MM biology and may function to both maintain MM cell viability as well as modify the tumor ME."
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A. Revenko et al. (apr 2022)
Journal for immunotherapy of cancer 10 4
Direct targeting of FOXP3 in Tregs with AZD8701, a novel antisense oligonucleotide to relieve immunosuppression in cancer.
BACKGROUND The Regulatory T cell (Treg) lineage is defined by the transcription factor FOXP3,which controls immune-suppressive gene expression profiles. Tregs are often recruited in high frequencies to the tumor microenvironment where they can suppress antitumor immunity. We hypothesized that pharmacological inhibition of FOXP3 by systemically delivered,unformulated constrained ethyl-modified antisense oligonucleotides could modulate the activity of Tregs and augment antitumor immunity providing therapeutic benefit in cancer models and potentially in man. METHODS We have identified murine Foxp3 antisense oligonucleotides (ASOs) and clinical candidate human FOXP3 ASO AZD8701. Pharmacology and biological effects of FOXP3 inhibitors on Treg function and antitumor immunity were tested in cultured Tregs and mouse syngeneic tumor models. Experiments were controlled by vehicle and non-targeting control ASO groups as well as by use of multiple independent FOXP3 ASOs. Statistical significance of biological effects was evaluated by one or two-way analysis of variance with multiple comparisons. RESULTS AZD8701 demonstrated a dose-dependent knockdown of FOXP3 in primary Tregs,reduction of suppressive function and efficient target downregulation in humanized mice at clinically relevant doses. Surrogate murine FOXP3 ASO,which efficiently downregulated Foxp3 messenger RNA and protein levels in primary Tregs,reduced Treg suppressive function in immune suppression assays in vitro. FOXP3 ASO promoted more than 70% reduction in FOXP3 levels in Tregs in vitro and in vivo,strongly modulated Treg effector molecules (eg,ICOS,CTLA-4,CD25 and 4-1BB),and augmented CD8+ T cell activation and produced antitumor activity in syngeneic tumor models. The combination of FOXP3 ASOs with immune checkpoint blockade further enhanced antitumor efficacy. CONCLUSIONS Antisense inhibitors of FOXP3 offer a promising novel cancer immunotherapy approach. AZD8701 is being developed clinically as a first-in-class FOXP3 inhibitor for the treatment of cancer currently in Ph1a/b clinical trial (NCT04504669).
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A. M. Chinn et al. ( 2022)
Frontiers in pharmacology 13 833832
PDE4B Is a Homeostatic Regulator of Cyclic AMP in Dendritic Cells.
Chronic decreases in the second messenger cyclic AMP (cAMP) occur in numerous settings,but how cells compensate for such decreases is unknown. We have used a unique system-murine dendritic cells (DCs) with a DC-selective depletion of the heterotrimeric GTP binding protein G$\alpha$s-to address this issue. These mice spontaneously develop Th2-allergic asthma and their DCs have persistently lower cAMP levels. We found that phosphodiesterase 4B (PDE4B) is the primary phosphodiesterase expressed in DCs and that its expression is preferentially decreased in G$\alpha$s-depleted DCs. PDE4B expression is dynamic,falling and rising in a protein kinase A-dependent manner with decreased and increased cAMP concentrations,respectively. Treatment of DCs that drive enhanced Th2 immunity with a PDE4B inhibitor ameliorated DC-induced helper T cell response. We conclude that PDE4B is a homeostatic regulator of cellular cAMP concentrations in DCs and may be a target for treating Th2-allergic asthma and other settings with low cellular cAMP concentrations.
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D. J. Friedman et al. (apr 2022)
Journal of immunology (Baltimore,Md. : 1950) 208 8 1845--1850
Cutting Edge: Enhanced Antitumor Immunity in ST8Sia6 Knockout Mice.
Inhibitory receptors have a critical role in the regulation of immunity. Siglecs are a family of primarily inhibitory receptors expressed by immune cells that recognize specific sialic acid modifications on cell surface glycans. Many tumors have increased sialic acid incorporation. Overexpression of the sialyltransferase ST8Sia6 on tumors led to altered immune responses and increased tumor growth. In this study,we examined the role of ST8Sia6 on immune cells in regulating antitumor immunity. ST8Sia6 knockout mice had an enhanced immune response to tumors. The loss of ST8Sia6 promoted an enhanced intratumoral activation of macrophages and dendritic cells,including upregulation of CD40. Intratumoral regulatory T cells exhibited a more inflammatory phenotype in ST8Sia6 knockout mice. Using adoptive transfer studies,the change in regulatory T cell phenotype was not cell intrinsic and depended on the loss of ST8Sia6 expression in APCs. Thus,ST8Sia6 generates ligands for Siglecs that dampen antitumor immunity.
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L. Rethacker et al. ( 2022)
Oncoimmunology 11 1 2057396
Innate lymphoid cells: NK and cytotoxic ILC3 subsets infiltrate metastatic breast cancer lymph nodes.
Innate lymphoid cells (ILCs) - which include cytotoxic Natural Killer (NK) cells and helper-type ILC - are important regulators of tissue immune homeostasis,with possible roles in tumor surveillance. We analyzed ILC and their functionality in human lymph nodes (LN). In LN,NK cells and ILC3 were the prominent subpopulations. Among the ILC3s,we identified a CD56+/ILC3 subset with a phenotype close to ILC3 but also expressing cytotoxicity genes shared with NK. In tumor-draining LNs (TD-LNs) and tumor samples from breast cancer (BC) patients,NK cells were prominent,and proportions of ILC3 subsets were low. In tumors and TD-LN,NK cells display reduced levels of NCR (Natural cytotoxicity receptors),despite high transcript levels and included a small subset CD127- CD56- NK cells with reduced function. Activated by cytokines CD56+/ILC3 cells from donor and patients LN acquired cytotoxic capacity and produced IFNg. In TD-LN,all cytokine activated ILC populations produced TNF$\alpha$ in response to BC cell line. Analyses of cytotoxic and helper ILC indicate a switch toward NK cells in TD-LN. The local tumor microenvironment inhibited NK cell functions through downregulation of NCR,but cytokine stimulation restored their functionality.
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M. D. Cheung et al. (jan 2022)
Kidney360 3 1 28--36
Single-Cell RNA Sequencing of Urinary Cells Reveals Distinct Cellular Diversity in COVID-19-Associated AKI.
BACKGROUND AKI is a common sequela of infection with SARS-CoV-2 and contributes to the severity and mortality from COVID-19. Here,we tested the hypothesis that kidney alterations induced by COVID-19-associated AKI could be detected in cells collected from urine. METHODS We performed single-cell RNA sequencing (scRNAseq) on cells recovered from the urine of eight hospitalized patients with COVID-19 with (n=5) or without AKI (n=3) as well as four patients with non-COVID-19 AKI (n=4) to assess differences in cellular composition and gene expression during AKI. RESULTS Analysis of 30,076 cells revealed a diverse array of cell types,most of which were kidney,urothelial,and immune cells. Pathway analysis of tubular cells from patients with AKI showed enrichment of transcripts associated with damage-related pathways compared with those without AKI. ACE2 and TMPRSS2 expression was highest in urothelial cells among cell types recovered. Notably,in one patient,we detected SARS-CoV-2 viral RNA in urothelial cells. These same cells were enriched for transcripts associated with antiviral and anti-inflammatory pathways. CONCLUSIONS We successfully performed scRNAseq on urinary sediment from hospitalized patients with COVID-19 to noninvasively study cellular alterations associated with AKI and established a dataset that includes both injured and uninjured kidney cells. Additionally,we provide preliminary evidence of direct infection of urinary bladder cells by SARS-CoV-2. The urinary sediment contains a wealth of information and is a useful resource for studying the pathophysiology and cellular alterations that occur in kidney diseases.
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S. Tahtinen et al. (apr 2022)
Nature immunology 23 4 532--542
IL-1 and IL-1ra are key regulators of the inflammatory response to RNA vaccines.
The use of lipid-formulated RNA vaccines for cancer or COVID-19 is associated with dose-limiting systemic inflammatory responses in humans that were not predicted from preclinical studies. Here,we show that the 'interleukin 1 (IL-1)-interleukin 1 receptor antagonist (IL-1ra)' axis regulates vaccine-mediated systemic inflammation in a host-specific manner. In human immune cells,RNA vaccines induce production of IL-1 cytokines,predominantly IL-1$\beta$,which is dependent on both the RNA and lipid formulation. IL-1 in turn triggers the induction of the broad spectrum of pro-inflammatory cytokines (including IL-6). Unlike humans,murine leukocytes respond to RNA vaccines by upregulating anti-inflammatory IL-1ra relative to IL-1 (predominantly IL-1$\alpha$),protecting mice from cytokine-mediated toxicities at >1,000-fold higher vaccine doses. Thus,the IL-1 pathway plays a key role in triggering RNA vaccine-associated innate signaling,an effect that was unexpectedly amplified by certain lipids used in vaccine formulations incorporating N1-methyl-pseudouridine-modified RNA to reduce activation of Toll-like receptor signaling.
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X. Guan et al. (jun 2022)
Nature 606 7915 791--796
Androgen receptor activity in T cells limits checkpoint blockade efficacy.
Immune checkpoint blockade has revolutionized the field of oncology,inducing durable anti-tumour immunity in solid tumours. In patients with advanced prostate cancer,immunotherapy treatments have largely failed1-5. Androgen deprivation therapy is classically administered in these patients to inhibit tumour cell growth,and we postulated that this therapy also affects tumour-associated T cells. Here we demonstrate that androgen receptor (AR) blockade sensitizes tumour-bearing hosts to effective checkpoint blockade by directly enhancing CD8 T cell function. Inhibition of AR activity in CD8 T cells prevented T cell exhaustion and improved responsiveness to PD-1 targeted therapy via increased IFN$\gamma$ expression. AR bound directly to Ifng and eviction of AR with a small molecule significantly increased cytokine production in CD8 T cells. Together,our findings establish that T cell intrinsic AR activity represses IFN$\gamma$ expression and represents a novel mechanism of immunotherapy resistance.
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P. Li et al. (mar 2022)
Journal for immunotherapy of cancer 10 3
1$\alpha$,25(OH)2D3 reverses exhaustion and enhances antitumor immunity of human cytotoxic T cells.
BACKGROUND Epidemiological surveys have revealed that low serum vitamin D level was correlated with increased risk of tumors. Dysfunctional T cells in patients with tumor are characterized as exhausted with high levels of immune checkpoint receptors (ICRs). However,whether the reduced level of vitamin D in patients with cancer correlates with cytotoxic T-cell exhaustion is unknown. METHODS Periphery blood samples from 172 patients with non-small cell lung cancer (NSCLC) were prospectively collected. Patients with NSCLC received one course of intravenous docetaxel (75 mg/m2) followed by treatment with or without rocaltrol at a dose of 0.5-2.0 µg/day for total of 3 weeks. We performed phenotypical and functional analysis of T-cell through flow cytometry. Vitamin D receptor (VDR) knockout and overexpression CD8+ and V$\delta$2+ T cells were constructed using Cas9-gRNA targeted and overexpressing approaches to identify 1$\alpha$,25(OH)2D3/VDR-mediated transcription regulation for ICRs or antitumor activity in T cells. RESULTS We show that serum level of vitamin D is negatively correlated with expression of programmed cell death-1 (PD-1),T-cell immunoreceptor with Ig and ITIM domains (TIGIT),and T-cell immunoglobulin and mucin-domain containing-3 (Tim-3),but positively correlated with CD28 expression on CD8+ and V$\gamma$9V$\delta$2+ T cells in patients with NSCLC. 1$\alpha$,25(OH)2D3,the active form of vitamin D,promotes the nuclear translocation of VDR,which binds to the promoter region of Pdcd1,Tim3,and Tigit genes and inhibits their expression. Besides,1$\alpha$,25(OH)2D3 pretreatment also promotes the methylation of CpG island in the promoter region of the Pdcd1 gene and increases H3K27 acetylation at the promoter region of the Cd28 gene,which leads to surface PD-1 downregulation and CD28 upregulation,respectively. We further reveal that VDR-mediated Ca2+ influx enhanced expression of Th1 cytokines via T-cell receptor activation. Functionally,1$\alpha$,25(OH)2D3 pretreated CD8+ T cells or V$\gamma$9V$\delta$2+ T cells showed increased Th1 cytokine production and enhanced antitumor immunity. Finally,oral 1$\alpha$,25(OH)2D3 could also decrease expression of PD-1,Tim-3,TIGIT and increase expression of CD28,resulting in cytokine production (associated with antitumor immunity) by cytotoxic T cells of patients with NSCLC. CONCLUSIONS Our findings uncover the pleiotropic effects of 1$\alpha$,25(OH)2D3 in rescuing the exhausted phenotype of human cytotoxic T cells in patients with tumor and in promoting their antitumor immunity. TRIAL REGISTRATION NUMBER ChiCTR2100051135.
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