A subset of megakaryocytes regulates development of hematopoietic stem cell precursors

Understanding the regulatory mechanisms facilitating hematopoietic stem cell (HSC) specification during embryogenesis is important for the generation of HSCs in vitro. Megakaryocyte emerged from the yolk sac and produce platelets, which are involved in multiple biological processes, such as preventing hemorrhage. However, whether megakaryocytes regulate HSC development in the embryonic aorta-gonad-mesonephros (AGM) region is unclear. Here, we use platelet factor 4 (PF4)-Cre;Rosa-tdTomato+ cells to report presence of megakaryocytes in the HSC developmental niche. Further, we use the PF4-Cre;Rosa-DTA (DTA) depletion model to reveal that megakaryocytes control HSC specification in the mouse embryos. Megakaryocyte deficiency blocks the generation and maturation of pre-HSCs and alters HSC activity at the AGM. Furthermore, megakaryocytes promote endothelial-to-hematopoietic transition in a OP9-DL1 coculture system. Single-cell RNA-sequencing identifies megakaryocytes positive for the cell surface marker CD226 as the subpopulation with highest potential in promoting the hemogenic fate of endothelial cells by secreting TNFSF14. In line, TNFSF14 treatment rescues hematopoietic cell function in megakaryocyte-depleted cocultures. Taken together, megakaryocytes promote production and maturation of pre-HSCs, acting as a critical microenvironmental control factor during embryonic hematopoiesis.

Tailoring vascular phenotype through AAV therapy promotes anti-tumor immunity in glioma

Glioblastomas are aggressive brain tumors that are largely immunotherapy resistant. This is associated with immunosuppression and a dysfunctional tumor vasculature, which hinder T cell infiltration. LIGHT/TNFSF14 can induce high endothelial venules (HEVs) and tertiary lymphoid structures (TLS), suggesting that its therapeutic expression could promote T cell recruitment. Here, we use a brain endothelial cell-targeted adeno-associated viral (AAV) vector to express LIGHT in the glioma vasculature (AAV-LIGHT). We found that systemic AAV-LIGHT treatment induces tumor-associated HEVs and T cell-rich TLS, prolonging survival in αPD-1-resistant murine glioma. AAV-LIGHT treatment reduces T cell exhaustion and promotes TCF1⁺CD8⁺ stem-like T cells, which reside in TLS and intratumoral antigen-presenting niches. Tumor regression upon AAV-LIGHT therapy correlates with tumor-specific cytotoxic/memory T cell responses. Our work reveals that altering vascular phenotype through vessel-targeted expression of LIGHT promotes efficient anti-tumor T cell responses and prolongs survival in glioma. These findings have broader implications for treatment of other immunotherapy-resistant cancers.

Lymphotoxin beta receptor signaling directly controls airway smooth muscle deregulation and asthmatic lung dysfunction

BACKGROUND

Dysregulation of airway smooth muscle cells (ASM) is central to the severity of asthma. Which molecules dominantly control ASM in asthma is unclear. High levels of the cytokine LIGHT (aka TNFSF14) have been linked to asthma severity and lower baseline predicted FEV1 percentage, implying that signals through its receptors might directly control ASM dysfunction.

OBJECTIVE

Our study sought to determine whether signaling via lymphotoxin beta receptor (LTβR) or herpesvirus entry mediator from LIGHT dominantly drives ASM hyperreactivity induced by allergen.

METHODS

Conditional knockout mice deficient for LTβR or herpesvirus entry mediator in smooth muscle cells were used to determine their role in ASM deregulation and airway hyperresponsiveness (AHR) in vivo. Human ASM were used to study signals induced by LTβR.

RESULTS

LTβR was strongly expressed in ASM from normal and asthmatic subjects compared to several other receptors implicated in smooth muscle deregulation. Correspondingly, conditional deletion of LTβR only in smooth muscle cells in smMHCCreLTβRfl/fl mice minimized changes in their numbers and mass as well as AHR induced by house dust mite allergen in a model of severe asthma. Intratracheal LIGHT administration independently induced ASM hypertrophy and AHR in vivo dependent on direct LTβR signals to ASM. LIGHT promoted contractility, hypertrophy, and hyperplasia of human ASM in vitro. Distinguishing LTβR from the receptors for IL-13, TNF, and IL-17, which have also been implicated in smooth muscle dysregulation, LIGHT promoted NF-κB-inducing kinase-dependent noncanonical nuclear factor kappa-light-chain enhancer of activated B cells in ASM in vitro, leading to sustained accumulation of F-actin, phosphorylation of myosin light chain kinase, and contractile activity.

CONCLUSIONS

LTβR signals directly and dominantly drive airway smooth muscle hyperresponsiveness relevant for pathogenesis of airway remodeling in severe asthma.

Triptolide increases resistance to bile duct ligation-induced liver injury and fibrosis in mice by inhibiting RELB

Cholestasis is a common, chronic liver disease that may cause fibrosis and cirrhosis. Tripterygium wilfordii Hook.f (TWHF) is a species in the Euonymus family that is commonly used as a source of medicine and food in Eastern and Southern China. Triptolide (TP) is an epoxy diterpene lactone of TWHF, as well as the main active ingredient in TWHF. Here, we used a mouse model of common bile duct ligation (BDL) cholestasis, along with cultured human intrahepatic biliary epithelial cells, to explore whether TP can relieve cholestasis. Compared with the control treatment, TP at a dose of 70 or 140 μg/kg reduced the serum levels of the liver enzymes alanine transaminase, aspartate aminotransferase, and alkaline phosphatase in mice; hematoxylin and eosin staining also showed that TP reduced necrosis in tissues. Both in vitro and in vivo analyses revealed that TP inhibited cholangiocyte proliferation by reducing the expression of RelB. Immunohistochemical staining of CK19 and Ki67, as well as measurement of Ck19 mRNA levels in hepatic tissue, revealed that TP inhibited the BDL-induced ductular reaction. Masson 3 and Sirius Red staining for hepatic hydroxyproline showed that TP alleviated BDL-induced hepatic fibrosis. Additionally, TP substantially inhibited BDL-induced hepatic inflammation. In summary, TP inhibited the BDL-induced ductular reaction by reducing the expression of RelB in cholangiocytes, thereby alleviating liver injury, fibrosis, and inflammation.

TNFSF14-Derived Molecules as a Novel Treatment for Obesity and Type 2 Diabetes

Obesity is one of the most prevalent metabolic diseases in the Western world and correlates directly with glucose intolerance and insulin resistance, often culminating in Type 2 Diabetes (T2D). Importantly, our team has recently shown that the TNF superfamily (TNFSF) member protein, TNFSF14, has been reported to protect against high fat diet induced obesity and pre-diabetes. We hypothesized that mimics of TNFSF14 may therefore be valuable as anti-diabetic agents. In this study, we use in silico approaches to identify key regions of TNFSF14 responsible for binding to the Herpes virus entry mediator and Lymphotoxin β receptor. In vitro evaluation of a selection of optimised peptides identified six potentially therapeutic TNFSF14 peptides. We report that these peptides increased insulin and fatty acid oxidation signalling in skeletal muscle cells. We then selected one of these promising peptides to determine the efficacy to promote metabolic benefits in vivo. Importantly, the TNFSF14 peptide 7 reduced high fat diet-induced glucose intolerance, insulin resistance and hyperinsulinemia in a mouse model of obesity. In addition, we highlight that the TNFSF14 peptide 7 resulted in a marked reduction in liver steatosis and a concomitant increase in phospho-AMPK signalling. We conclude that TNFSF14-derived molecules positively regulate glucose homeostasis and lipid metabolism and may therefore open a completely novel therapeutic pathway for treating obesity and T2D.

Molecular and Clinical Characterization of LIGHT/TNFSF14 Expression at Transcriptional Level via 998 Samples With Brain Glioma

LIGHT, also termed TNFSF14, has been reported to play a vital role in different tumors. However, its role in glioma remains unknown. This study is aimed at unveiling the characterization of the transcriptional expression profiling of LIGHT in glioma. We selected 301 glioma patients with mRNA microarray data from the CGGA dataset and 697 glioma patients with RNAseq data from the TCGA dataset. Transcriptome data and clinical data of 998 samples were analyzed. Statistical analyses and figure generation were performed with R language. LIGHT expression showed a positive correlation with WHO grade of glioma. LIGHT was significantly increased in mesenchymal molecular subtype. Gene Ontology analysis demonstrated that LIGHT was profoundly involved in immune response. Moreover, LIGHT was found to be synergistic with various immune checkpoint members, especially HVEM, PD1/PD-L1 pathway, TIM3, and B7-H3. To get further understanding of LIGHT-related immune response, we put LIGHT together with seven immune signatures into GSVA and found that LIGHT was particularly correlated with HCK, LCK, and MHC-II in both datasets, suggesting a robust correlation between LIGHT and activities of macrophages, T-cells, and antigen-presenting cells (APCs). Finally, higher LIGHT indicated significantly shorter survival for glioma patients. Cox regression models revealed that LIGHT expression was an independent variable for predicting survival. In conclusion, LIGHT was upregulated in more malignant gliomas including glioblastoma, IDH wildtype, and mesenchymal subtype. LIGHT was mainly involved in the immune function of macrophages, T cells, and APCs and served as an independent prognosticator in glioma.

Genomic and functional evaluation of TNFSF14 in multiple sclerosis susceptibility

Among multiple sclerosis (MS) susceptibility genes, the strongest non-human leukocyte antigen (HLA) signal in the Italian population maps to the TNFSF14 gene encoding LIGHT, a glycoprotein involved in dendritic cell (DC) maturation. Through fine-mapping in a large Italian dataset (4,198 patients with MS and 3,903 controls), we show that the TNFSF14 intronic SNP rs1077667 is the primarily MS-associated variant in the region. Expression quantitative trait locus (eQTL) analysis indicates that the MS risk allele is significantly associated with reduced TNFSF14 messenger RNA levels in blood cells, which is consistent with the allelic imbalance in RNA-Seq reads (P < 0.0001). The MS risk allele is associated with reduced levels of TNFSF14 gene expression (P < 0.01) in blood cells from 84 Italian patients with MS and 80 healthy controls (HCs). Interestingly, patients with MS are lower expressors of TNFSF14 compared to HC (P < 0.007). Individuals homozygous for the MS risk allele display an increased percentage of LIGHT-positive peripheral blood myeloid DCs (CD11c⁺, P = 0.035) in 37 HCs, as well as in in vitro monocyte-derived DCs from 22 HCs (P = 0.04). Our findings suggest that the intronic variant rs1077667 alters the expression of TNFSF14 in immune cells, which may play a role in MS pathogenesis.

Increased level of LIGHT/TNFSF14 is associated with survival in aneurysmal subarachnoid hemorrhage

OBJECTIVES

Multiple cytokines have been implicated in aneurysmal subarachnoid hemorrhage (aSAH), but tumor necrosis factor superfamily 14 (LIGHT/TNFSF14) and oncostatin-M (OSM) have not been previously explored.

AIMS OF THE STUDY

The primary objective of this study was to examine the relationship between TNFSF14 and OSM levels and survival. Our secondary goal was to investigate a potential association between these markers and the incidence of delayed cerebral ischemia (DCI).

MATERIALS & METHODS

We consecutively recruited 60 patients with a clinical diagnosis of aSAH. LIGHT/TNFSF14 and OSM serum concentrations were determined by ELISA. The primary endpoint was survival at Day 30, while development of DCI was assessed as secondary outcome.

RESULTS

Patients had significantly higher levels of both markers than the control group (median of LIGHT: 18.1 pg/ml vs. 7 pg/ml; p = 0.01; median of OSM: 10.3 pg/ml vs. 2.8 pg/ml, p < 0.001). Significantly lower serum level of LIGHT/TNFSF14 was found in nonsurviving patients (n = 9) compared with survivors (n = 51; p = 0.011). Based on ROC analysis, serum LIGHT/TNFSF14 with a cutoff value of >7.95 pg/ml predicted 30-day survival with a sensitivity of 71% and specificity of 78% (Area: 0.763; 95% CI: 0.604-0.921, p = 0.013). In addition, it was also a predictor of DCI with a sensitivity of 72.7% and a specificity of 62.5% (AUC: 0.702; 95% CI: 0.555-0.849, p = 0.018). Based on binary logistic regression analysis, LIGHT/TNFSF14 was found to be independently associated with 30-day mortality, but not with DCI.

CONCLUSION

In this cohort, a higher serum level of LIGHT/TNFSF14 was associated with increased survival of patients with aSAH.

Combination Immunotherapy With LIGHT and Interleukin-2 Increases CD8 Central Memory T-Cells In Vivo

BACKGROUND

The generation of long-term durable tumor immunity and prolonged disease-free survival depends on the ability to generate and support CD8+ central memory T-cells. Microsatellite-stable colon cancer is resistant to currently available immunotherapies; thus, development of novel mechanisms to increase both lymphocyte infiltration and central memory formation are needed to improve outcomes in these patients. We have previously demonstrated that both interleukin-2 (IL-2) and LIGHT (TNFSF14) independently enhance antitumor immune responses and hypothesize that combination immunotherapy may increase the CD8+ central memory T-cell response.

METHODS

Murine colorectal cancer tumors were established in syngeneic mice. Tumors were treated with control, soluble, or liposomal IL-2 at established intervals. A subset of animal tumors overexpressed tumor necrosis superfamily factor LIGHT (TNFSF14). Peripheral blood, splenic, and tumor-infiltrating lymphocytes were isolated for phenotypic studies and flow cytometry.

RESULTS

Tumors exposed to a combination of LIGHT and IL-2 experienced a decrease in tumor size compared with IL-2 alone that was not demonstrated in wild-type tumors or between other treatment groups. Combination exposure also increased splenic central memory CD8+ cells compared with IL-2 administration alone, while not increasing tumor-infiltrating lymphocytes. In the periphery, the combination enhanced levels of circulating CD8 T-cells and central memory T-cells, while also increasing circulating T-regulatory cells.

CONCLUSIONS

Combination of IL-2, whether soluble or liposomal, with exposure to LIGHT results in increased CD8+ central memory cells in the spleen and periphery. New combination immunotherapy strategies that support both effector and memory T-cell functions are critical to enhancing durable antitumor responses and warrant further investigation.

Polymorphisms within the TNFSF4 and MAPKAPK2 Loci Influence the Risk of Developing Invasive Aspergillosis: A Two-Stage Case Control Study in the Context of the aspBIOmics Consortium

Here, we assessed whether 36 single nucleotide polymorphisms (SNPs) within the TNFSF4 and MAPKAPK2 loci influence the risk of developing invasive aspergillosis (IA). We conducted a two-stage case control study including 911 high-risk patients diagnosed with hematological malignancies that were ascertained through the aspBIOmics consortium. The meta-analysis of the discovery and replication populations revealed that carriers of the TNFSF4 _rs7526628T/T genotype had a significantly increased risk of developing IA (p = 0.00022). We also found that carriers of the TNFSF4 _rs7526628T allele showed decreased serum levels of TNFSF14 protein (p = 0.0027), and that their macrophages had a decreased fungicidal activity (p = 0.048). In addition, we observed that each copy of the MAPKAPK2 _rs12137965G allele increased the risk of IA by 60% (p = 0.0017), whereas each copy of the MAPKAPK2 _rs17013271T allele was estimated to decrease the risk of developing the disease (p = 0.0029). Mechanistically, we found that carriers of the risk MAPKAPK2 _rs12137965G allele showed increased numbers of CD38+IgM-IgD- plasmablasts in blood (p = 0.00086), whereas those harboring two copies of the allele had decreased serum concentrations of thymic stromal lymphopoietin (p = 0.00097). Finally, we also found that carriers of the protective MAPKAPK2 _rs17013271T allele had decreased numbers of CD27-IgM-IgD- B cells (p = 0.00087) and significantly lower numbers of CD14+ and CD14+CD16- cells (p = 0.00018 and 0.00023). Altogether, these results suggest a role of the TNFSF4 and MAPKAPK2 genes in determining IA risk.

Tumor necrosis factor superfamily 14 is critical for the development of renal fibrosis

Objective: Tumor necrosis factor superfamily protein 14 (TNFSF14) was recently identified as a risk factor in some fibrosis diseases. However, the role of TNFSF14 in renal fibrosis pathogenesis remains unknown.

Results: It was found that TNFSF14 levels were significantly increased both in UUO-induced renal fibrotic mice and in patients with fibrotic nephropathy, compared with those in controls. Accordingly, Tnfsf14 deficiency led to a marked reduction in renal fibrosis lesions and inflammatory cytokines expression in the UUO mice. Furthermore, the levels of Sphk1, a critical molecule that causes fibrotic nephropathy, were remarkably reduced in Tnfsf14 KO mice with UUO surgery. In vitro recombinant TNFSF14 administration markedly up-regulated the expression of Sphk1 of primary mouse renal tubular epithelial cells (mTECs).

Conclusion: TNFSF14 is a novel pro-fibrotic factor of renal fibrosis, for which TNFSF14 up-regulates Sphk1 expression, which may be the underlying mechanism of TNFSF14-mediated renal fibrosis.

Methods: We investigated the effect of TNFSF14 on renal fibrosis and the relationship between TNFSF14 and pro-fibrotic factor sphingosine kinase 1 (Sphk1) by using the unilateral urethral obstruction (UUO)-induced mice renal fibrosis as a model and the specimen of patients with fibrosis nephropathy, by Masson trichrome staining, immunohistochemistry, qRT-PCR, and western blot analysis.

The Influence of Hypertensive Therapies on Circulating Factors: Clinical Implications for SCFAs, FGF21, TNFSF14 and TNF-α

Studying the role of circulatory factors in the pathogenesis of diseases has been key to the development of effective therapies. We sought to examine the effect of antihypertensive therapies on numerous circulatory factors including short chain fatty acids and growth factors in a human cohort. A subset of participants from an earlier study was characterized by their hypertensive and/or treatment status and separated into three groups: (i) normotensives; (ii) untreated hypertensive and (iii) treated hypertensive subjects. Circulating levels of short chain fatty acids, FGF21 and TNF superfamily members were measured as part of this study. Both F2-isoprostane and circulating lipid levels were reanalysed as part of this current study. We found that antihypertensive treatment increased butyrate levels and decreased acetate levels to levels similar to normotensives. We also found that antihypertensive treatments reduced levels of circulating FGF21, TNFSF14 and TNF-α. In conclusion, we identified several circulatory factors that are altered in hypertension.

Levels of the TNF-Related Cytokine LIGHT Increase in Hospitalized COVID-19 Patients with Cytokine Release Syndrome and ARDS

Many coronavirus disease 2019 (COVID-19) patients demonstrate lethal respiratory complications caused by cytokine release syndrome (CRS). Multiple cytokines have been implicated in CRS, but levels of tumor necrosis factor superfamily 14 (TNFSF14) (LIGHT) have not been previously measured in this setting. In this study, we observed significantly elevated serum LIGHT levels in hospitalized COVID-19 patients compared to healthy age- and gender-matched control patients. The assay detected bioavailable LIGHT unbound to the inhibitor Decoy receptor-3 (DcR3). Bioavailable LIGHT levels were elevated in patients both on and off ventilatory support, with a trend toward higher levels in patients requiring mechanical ventilation. In hospitalized patients over the age of 60, who exhibited a mortality rate of 82%, LIGHT levels were significantly higher (P = 0.0209) in those who died than in survivors. As previously reported, interleukin 6 (IL-6) levels were also elevated in these patients, with significantly (P = 0.0076) higher levels observed in patients who died than in survivors, paralleling the LIGHT levels. Although attempts to block IL-6 binding to its receptor have shown limited success in COVID-19 CRS, neutralization of LIGHT may prove to be more effective owing to its more central role in regulating antiviral immune responses. The findings presented here demonstrate that LIGHT is a cytokine which may play an important role in COVID-19 patients presenting with acute respiratory distress syndrome (ARDS) and CRS and suggest that LIGHT neutralization may be beneficial to COVID-19 patients.

The impact of TNFSF14 on prognosis and immune microenvironment in clear cell renal cell carcinoma

BACKGROUND

TNFSF14 has been proven to play an important role in various types of tumors. However, its function in renal cell carcinoma (RCC) has not yet been fully elucidated.

OBJECTIVE

In order to explore molecular mechanism of RCC, we evaluated the effect of TNFSF14 on RCC progression, prognosis and immune microenvironment.

METHODS

Using TCGA database, the differential expression of TNFSF14 and its relationships between clinicopathological features and prognosis were determined. Cox univariate and multivariate analyses were successively performed to identify whether TNFSF14 was an independent prognostic factor. The discriminating ability of TNFSF14 in RCC prognosis analysis was validated under the same clinical subgroups. Tumor mutational burden (TMB) of each RCC samples was calculated and the differential expression of TNFSF14 between high- and low-TMB groups was analyzed. The immune abundances of 22 leukocyte subtypes in each RCC samples were presented through the CIBERSORT algorithm. TIMER database was used to explore the relationships between copy number of TNFSF14 and the infiltration levels of 6 immune cells.

RESULTS

Overexpression of TNFSF14 implied adverse clinicopathological features and poor prognosis. Meanwhile, TNFSF14 was identified as an independent prognostic factor (HR = 1.047, P = 0.028) and possessed prevalent applicability in RCC prognostic analysis. TNFSF14 was upregulated in high-TMB group than that in low-TMB group (Log₂FC = 0.722). Moreover, overexpression of TNFSF14 brought alteration of immune abundance of 8 leukocyte subtypes. Besides, somatic copy number alteration (SCNA) of TNFSF14 was associated with infiltration levels of 6 immune cells.

CONCLUSIONS

TNFSF14 has crucial impact on progression, prognosis and immune microenvironment in RCC. Besides, TNFSF14 may be a potential biomarker for predicting the efficacy and response rate of RCC immunotherapy.

Identification of immunologic subtype and prognosis of GBM based on TNFSF14 and immune checkpoint gene expression profiling

Immune-checkpoint therapy has failed to show significant benefit in glioblastoma (GBM) patients. Immunologic subtypes of GBM are necessary to identify patients who might benefit from immune-checkpoint therapy. This study reviewed 152 GBM samples from The Cancer Genome Atlas (TCGA) and 214 GBM samples from Chinese Glioma Genome Atlas (CGGA). Correlation analysis showed that immune checkpoint genes (ICGs) were mainly positively correlated. The prognostic analysis of the overall survival showed that there was a significant correlation between the overall survival (OS) and the prognosis of ICGs, in which the TNFSF14 gene was a significant adverse prognostic factor. Combined with TMB and neoantigens, we found that TNFSF9 and CD27 were significantly negatively correlated with TMB and neoantigens. The association between adaptive immune pathway genes and ICG expression showed that they were positively correlated with ICGs, indicating that adaptive immune pathway genes have a certain regulatory effect on the expression of ICGs. The analysis of clinical features of the samples showed that the higher the expression of ICGs, the more likely to be correlated with mutant isocitrate dehydrogenase (IDH), while the lower the expression level of IDH, the more likely to be significantly correlated with the primary GBM. Survival analysis showed that low expression of PD-L1, IDO1, or CTLA4 with TNFSF14 in the low expression group had the best prognosis, while high expression of IDO1 or CD274 with TNFSF14 in the high expression group and low expression of CTLA4 with TNFSF14 in the high expression group had the worst prognosis. We conclude that TNFSF14 is a biomarker to identify immunologic subtype and prognosis with other ICGs in GBM and may serve as a potential therapeutic target.

TNFSF14, a novel target of miR-326, facilitates airway remodeling in airway smooth muscle cells via inducing extracellular matrix protein deposition and proliferation

As a common chronic respiratory disease, the incidence of asthma is increasing in recent years worldwide. Airway remodeling is the primary pathological basis of refractory asthma, but the studies about the underlying mechanism of airway remodeling was a lack. In the study, we aimed to investigate the effects and mechanisms of miR-326 on airway remodeling in airway smooth muscle cells (ASMCs). The results showed that transforming growth factor-β1 (TGF-β1) accelerated matrix protein deposition by increasing the expression levels of collagen I and fibronectin, and promoted proliferative ability of ASMCs. However, miR-326 was significantly downregulated in TGF-β1-treated ASMCs. MiR-326 mimics robustly decreased the collagen I and fibronectin levels and inhibited cell proliferation of TGF-β1-treated ASMCs. Luciferase assay investigated that tumor necrosis factor superfamily member 14 (TNFSF14) was a direct target of miR-326. The expression of TNFSF14 was negatively regulated by miR-326. Moreover, exogenous TNFSF14 effectively reversed the inhibitory effects of miR-326 overexpression on the expression levels of collagen I and fibronectin, and promoted cell proliferation of TGF-β1-treated ASMCs. In conclusion, miR-326 suppressed matrix protein deposition and cell proliferation of TGF-β1-treated ASMCs via inhibiting TNFSF14. MiR-326 might be a promising novel therapeutic target for asthma.

Structural Remodeling of the Human Colonic Mesenchyme in Inflammatory Bowel Disease

Intestinal mesenchymal cells play essential roles in epithelial homeostasis, matrix remodeling, immunity, and inflammation. But the extent of heterogeneity within the colonic mesenchyme in these processes remains unknown. Using unbiased single-cell profiling of over 16,500 colonic mesenchymal cells, we reveal four subsets of fibroblasts expressing divergent transcriptional regulators and functional pathways, in addition to pericytes and myofibroblasts. We identified a niche population located in proximity to epithelial crypts expressing SOX6, F3 (CD142), and WNT genes essential for colonic epithelial stem cell function. In colitis, we observed dysregulation of this niche and emergence of an activated mesenchymal population. This subset expressed TNF superfamily member 14 (TNFSF14), fibroblastic reticular cell-associated genes, IL-33, and Lysyl oxidases. Further, it induced factors that impaired epithelial proliferation and maturation and contributed to oxidative stress and disease severity in vivo. Our work defines how the colonic mesenchyme remodels to fuel inflammation and barrier dysfunction in IBD.

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Single-cell census of the colonic mesenchyme reveals unexpected heterogeneity

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Identification of the colonic crypt niche mesenchymal cell expressing SOX6 and Wnts

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Definition of fundamental aspects of mesenchymal remodeling in colitis

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Analysis of colitis-associated mesenchymal cells reveals pathogenicity drivers

EnLIGHTenment of tumor vessel normalization and immunotherapy in glioblastoma

Glioblastoma multiforme (GBM) is a highly vascularized and aggressive brain tumor. Despite aggressive standard care, GBM remains predominantly fatal; hence, new innovative therapies are required. Recent research published in the Journal of Pathology has identified the CGKRK peptide as a promising tool with which to specifically target the tumor vasculature from high-grade glioma. This tumor vessel-homing peptide was fused to the tumor necrosis factor superfamily member LIGHT/TNFSF14, and injected intravenously into murine orthotopic GBM models. After treatment, the tumor vasculature appeared to be less abnormal, with normalized features such as increased endothelial barrier integrity, pericyte contractility, and tumor perfusion. Moreover, CGKRK-LIGHT induced the appearance of high endothelial venules (HEVs), which are specialized structures that play a role in lymphocyte trafficking and have been shown to increase T-cell infiltration in solid tumors. Combining CGKRK-LIGHT with anti-angiogenic and immune checkpoint blockade treatments boosted HEV induction and cytotoxic T-cell infiltration, leading to a reduction in tumor burden. In this Commentary, I highlight the therapeutic opportunities provided by and the current limitations of LIGHT-vascular targeting peptide as a new approach to target GBM and enhance tumor vessel delivery and immunotherapy efficacy. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

TNFSF14/LIGHT, a Non-Canonical NF-κB Stimulus, Induces the HIF Pathway

Non-canonical NF-κB signalling plays important roles in the development and function of the immune system but it also is deregulated in a number of inflammatory diseases. Although, NF-κB and HIF crosstalk has been documented, this has only been described following canonical NF-κB stimulation, involving RelA/p50 and the HIF-1 dimer. Here, we report that the non-canonical inducer TNFSF14/LIGHT leads to HIF induction and activation in cancer cells. We demonstrate that only HIF-2α is induced at the transcriptional level following non-canonical NF-κB activation, via a mechanism that is dependent on the p52 subunit. Furthermore, we demonstrate that p52 can bind to the HIF-2α promoter in cells. These results indicate that non-canonical NF-κB can lead to HIF signalling implicating HIF-2α as one of the downstream effectors of this pathway in cells.

Tumor necrosis factor family member LIGHT acts with IL-1β and TGF-β to promote airway remodeling during rhinovirus infection

BACKGROUND

Rhinovirus (RV) can exacerbate allergen-driven asthma. However, it has been suggested that serial infections with RV may also lead to asthma-like features in childhood without prior allergen exposure.

AIM

We sought to test the effects of RV infection in the absence of allergen challenge on lung tissue remodeling and to understand whether RV induced factors in common with allergen that promote remodeling.

METHODS

We infected C57BL/6 mice multiple times with RV in the absence or presence of allergen to assess airway remodeling. We used knockout mice and blocking reagents to determine the participation of LIGHT (TNFSF14), as well as IL-1β and TGF-β, each previously shown to contribute to lung remodeling driven by allergen.

RESULTS

Recurrent RV infection without allergen challenge induced an increase in peribronchial smooth muscle mass and subepithelial fibrosis. Rhinovirus (RV) induced LIGHT expression in mouse lungs after infection, and alveolar epithelial cells and neutrophils were found to be potential sources of LIGHT. Accordingly, LIGHT-deficient mice, or mice where LIGHT was neutralized, displayed reduced smooth muscle mass and lung fibrosis. Recurrent RV infection also exacerbated the airway remodeling response to house dust mite allergen, and this was significantly reduced in LIGHT-deficient mice. Furthermore, neutralizing IL-1β or TGF-β also limited subepithelial fibrosis and/or smooth muscle thickness induced by RV.

CONCLUSION

Rhinovirus can promote airway remodeling in the absence of allergen through upregulating common factors that also contribute to allergen-associated airway remodeling.

TNFSF14 inhibits melanogenesis via NF-kB signaling in melanocytes

Melanin synthesis in melanocytes is affected by various cytokines. Here, we reported for the first time that tumor necrosis factor superfamily member 14 (TNFSF14) inhibits melanogenesis in the primary culture of human epidermal melanocytes. TNFSF14 is known to bind to its receptors herpes virus entry mediator (HVEM) and lymphotoxin β receptor (LTβR) for signal transduction, but TNFSF14-induced hypopigmentation was independent of HVEM and LTβR in melanocytes. To explore signaling in melanocytes treated with TNFSF14, we performed RNA-seq and found that nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) signaling is activated by TNFSF14. Further, we observed that inhibition of NF-kB effectively blocks the hypopigmentation induced by TNFSF14. We conclude that TNFSF14 inhibits melanogenesis in melanocytes via NF-κB signaling and could be applied in the treatment of cutaneous pigment disorders.

Vascular targeting of LIGHT normalizes blood vessels in primary brain cancer and induces intratumoural high endothelial venules

High-grade brain cancer such as glioblastoma (GBM) remains an incurable disease. A common feature of GBM is the angiogenic vasculature, which can be targeted with selected peptides for payload delivery. We assessed the ability of micelle-tagged, vascular homing peptides RGR, CGKRK and NGR to specifically bind to blood vessels in syngeneic orthotopic GBM models. By using the peptide CGKRK to deliver the tumour necrosis factor (TNF) superfamily member LIGHT (also known as TNF superfamily member 14; TNFSF14) to angiogenic tumour vessels, we have generated a reagent that normalizes the brain cancer vasculature by inducing pericyte contractility and re-establishing endothelial barrier integrity. LIGHT-mediated vascular remodelling also activates endothelia and induces intratumoural high endothelial venules (HEVs), which are specialized blood vessels for lymphocyte infiltration. Combining CGKRK-LIGHT with anti-vascular endothelial growth factor and checkpoint blockade amplified HEV frequency and T-cell accumulation in GBM, which is often sparsely infiltrated by immune effector cells, and reduced tumour burden. Furthermore, CGKRK and RGR peptides strongly bound to blood vessels in freshly resected human GBM, demonstrating shared peptide-binding activities in mouse and human primary brain tumour vessels. Thus, peptide-mediated LIGHT targeting is a highly translatable approach in primary brain cancer to reduce vascular leakiness and enhance immunotherapy. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Forced LIGHT expression in prostate tumors overcomes Treg mediated immunosuppression and synergizes with a prostate tumor therapeutic vaccine by recruiting effector T lymphocytes

BACKGROUND

LIGHT, a ligand for lymphotoxin-β receptor (LTβR) and herpes virus entry mediator, is predominantly expressed on activated immune cells and LTβR signaling leads to the recruitment of lymphocytes. The interaction between LIGHT and LTβR has been previously shown to activate immune cells and result in tumor regression in a virally-induced tumor model, but the role of LIGHT in tumor immunosuppression or in a prostate cancer setting, where self antigens exist, has not been explored. We hypothesized that forced expression of LIGHT in prostate tumors would shift the pattern of immune cell infiltration toward an anti-tumoral milieu, would inhibit T regulatory cells (Tregs) and would induce prostate cancer tumor associated antigen (TAA) specific T cells that would eradicate tumors.

METHODS

Real Time PCR was used to evaluate expression of forced LIGHT and other immunoregulatory genes in prostate tumors samples. For in vivo studies, adenovirus encoding murine LIGHT was injected intratumorally into TRAMP-C2 prostate cancer cell tumor bearing mice. Chemokine and cytokine concentrations were determined by multiplex ELISA. Flow cytometry was used to phenotype tumor infiltrating lymphocytes and expression of LIGHT on the tumor cell surface. Tumor-specific lymphocytes were quantified via ELISpot assay. Treg induction and Treg suppression assays determined Treg functionality after LIGHT treatment.

RESULTS

LIGHT in combination with a therapeutic vaccine, PSCA TriVax, reduced tumor burden. LIGHT expression peaked within 48 hr of infection, recruited effector T cells that recognized mouse prostate stem cell antigen (PSCA) into the tumor microenvironment, and inhibited infiltration of Tregs. Tregs isolated from tumor draining lymph nodes had impaired suppressive capability after LIGHT treatment.

CONCLUSION

Forced LIGHT treatment combined with PSCA TriVax therapeutic vaccination delays prostate cancer progression in mice by recruiting effector T lymphocytes to the tumor and inhibiting Treg mediated immunosuppression. Prostate 75:280-291, 2015. © 2014 Wiley Periodicals, Inc.

Tumor necrosis factor superfamily 14 (LIGHT) controls thymic stromal lymphopoietin to drive pulmonary fibrosis

BACKGROUND

Pulmonary fibrosis is characterized by excessive accumulation of collagen and α-smooth muscle actin in the lung. The key molecules that promote these phenotypes are of clinical interest.

OBJECTIVES

Thymic stromal lymphopoietin (TSLP) has been found at high levels in patients with asthma and idiopathic pulmonary fibrosis, and TSLP has been proposed as a primary driver of lung fibrotic disease. We asked whether tumor necrosis factor superfamily protein 14 (TNFSF14) (aka LIGHT) controls TSLP production to initiate fibrosis.

METHODS

Expression of TSLP and initiation of pulmonary fibrosis induced by bleomycin were assessed in mice deficient in LIGHT. The ability of recombinant LIGHT, given intratracheally to naive mice, to promote TSLP and fibrosis was also determined.

RESULTS

Genetic deletion of LIGHT abolished lung TSLP expression driven by bleomycin, accompanied by near-complete absence of accumulation of lung collagen and α-smooth muscle actin. Furthermore, recombinant LIGHT administered in vivo induced lung expression of TSLP in the absence of other inflammatory stimuli, and strikingly reproduced the primary features of bleomycin-driven disease in a TSLP-dependent manner. Blockade of LIGHT binding to either of its receptors, herpes virus entry mediator and lymphotoxin beta receptor, inhibited clinical symptoms of pulmonary fibrosis, and correspondingly both receptors were found on human bronchial epithelial cells, a primary source of TSLP. Moreover, LIGHT induced TSLP directly in human bronchial epithelial cells and synergized with IL-13 and TGF-β in vivo to promote TSLP in the lungs and drive fibrosis.

CONCLUSIONS

These results show that LIGHT is a profibrogenic cytokine that may be a key driver of TSLP production during the initiation and development of lung fibrotic disease.

Licensed human natural killer cells aid dendritic cell maturation via TNFSF14/LIGHT. Proc Natl Acad Sci U S A. 2014;111:E5688-E5696. [PMID: 25512551 DOI: 10.1073/pnas.1411072112]

Interactions between natural killer (NK) cells and dendritic cells (DCs) aid DC maturation and promote T-cell responses. Here, we have analyzed the response of human NK cells to tumor cells, and we identify a pathway by which NK-DC interactions occur. Gene expression profiling of tumor-responsive NK cells identified the very rapid induction of TNF superfamily member 14 [TNFSF14; also known as homologous to lymphotoxins, exhibits inducible expression, and competes with HSV glycoprotein D for HVEM, a receptor expressed by T lymphocytes (LIGHT)], a cytokine implicated in the enhancement of antitumor responses. TNFSF14 protein expression was induced by three primary mechanisms of NK cell activation, namely, via the engagement of CD16, by the synergistic activity of multiple target cell-sensing NK-cell activation receptors, and by the cytokines IL-2 and IL-15. For antitumor responses, TNFSF14 was preferentially produced by the licensed NK-cell population, defined by the expression of inhibitory receptors specific for self-MHC class I molecules. In contrast, IL-2 and IL-15 treatment induced TNFSF14 production by both licensed and unlicensed NK cells, reflecting the ability of proinflammatory conditions to override the licensing mechanism. Importantly, both tumor- and cytokine-activated NK cells induced DC maturation in a TNFSF14-dependent manner. The coupling of TNFSF14 production to tumor-sensing NK-cell activation receptors links the tumor immune surveillance function of NK cells to DC maturation and adaptive immunity. Furthermore, regulation by NK cell licensing helps to safeguard against TNFSF14 production in response to healthy tissues.