Fas Receptor Research Articles

Causal role of the pyrimidine deoxyribonucleoside degradation superpathway mediation in Guillain-Barré Syndrome via the HVEM on CD4 + and CD8 + T cells

Immune system regulation is a key indicator of the gut microbiota (GM) influencing disease development. The causal role of the GM in Guillain-Barré syndrome (GBS) and whether it can be mediated by immune cells is unknown. Genome-wide association study (GWAS) summary statistics for the GM were obtained from the Dutch Microbiota Project (n = 7,738) and the FINRISK 2002 (FR02) cohort (n = 5,959). Inverse variance weighting method (IVW) were used as the main method to evaluate the causal relationship between GM and GBS. Subsequently, the mediating effects of 731 immune traits were evaluated. Additionally, we also executed the Bayesian Weighting algorithm for verification. Mendelian randomization (MR) analysis determined the protective effect of the pyrimidine deoxyribonucleoside degradation superpathway on GBS (IVW: P = 0.0019, OR = 0.4508). It is worth noting that in the causal effects of pyrimidine deoxyribonucleoside degradation superpathway on GBS, the mediated proportions of herpesvirus entry mediator (HVEM) ( HVEM on CM CD4 + , HVEM on naive CD4 + , HVEM on CD45RA − CD4 + , HVEM on CM CD8br) in the T cell maturation stage on GBS were -0.0398, -0.0452, -0.0414, -0.0425, accounting for 5.00%, 5.67%, 5.19% and 5.34% of the total effect. 11 types of intestinal bacteria might be involved in the pyrimidine deoxyriboside degradation superpathway, including Staphylococcus A fleurettii, AR31,CAG-274 sp000432155, Photobacterium, Acetobacteraceae, Dysgonomonadaceae, NK4A144,Leptospirae, CAG-81 sp000435795, Leptospirales and CAG-873 sp001701165. This study suggests that there is a causal relationship between pyrimidine deoxyribonucleoside degradation superpathway and GBS, which may be mediated by HVEM on CD4 + and CD8 + T cells. As a bidirectional molecular switch, HVEM plays an important role in T cell regulation. 11 intestinal flora were found to be involved in pyrimidine deoxyribonucleoside degradation superpathway, and their changes may be related to the occurrence of GBS. However, extensive research is still warranted before microbiome sequencing can be used for prevention and targeted treatment of GBS.

Associations between T-cell traits and narcolepsy type 1: new insights from a Mendelian randomization study.

Narcolepsy type 1 (NT1) is primarily caused by a malfunctioning immune system in which T-cells damage the hypothalamus. To elucidate the causal relationships between biomarkers in T-cells and NT1, we employed Mendelian randomization (MR) analysis. We conducted a two-sample MR analysis utilizing genetically predicted T-cell traits to examine their effects on NT1. Genome-wide association study summary data were extracted from studies by Valeria (3,757 participants) for 211 T-cell traits, Ollila (6,073 cases and 84,856 controls) for NT1. The MR analysis was executed at two threshold levels. Inverse variance weighted, Wald ratio, weighted median, and MR-Egger regression methods were used for the MR analysis. Odds ratios (ORs) were calculated, and heterogeneity tests, as well as pleiotropy tests, were conducted. After Bonferroni correction at the significant level (p < 1.18 × 10-4), a higher ratio of naive CD4- CD8- T-cells was identified as a risk factor for NT1 (OR = 10.50; 95% CI: 6.98, 15.90, p = 3.89 ×10-29). Conversely, CD4 on HLA DR+ CD4+ T cells (mean fluorescence intensity, MFI) exhibited a negative correlation with NT1. At nominally significant levels (p < 0.05) for both threshold levels, HVEM (herpesvirus entry mediator) on naive CD8+ T cells (MFI) was suggested as a protective factor for NT1. Additionally, a higher ratio of CD25++ CD45RA- CD4 not regulatory T cells, CD127 on CD45RA- CD4 not regulatory T cells (MFI), CD127 on CD28+ CD4+ T cells (MFI), CD3 on HLA DR+ T cells (MFI), and CD3 on HLA DR+ CD4+ T cells (MFI) were suggested as risk factors for NT1. This study confirmed the causal effects of CD4+ and CD8+ T-cells on NT1 and found several novel T-cell-related characteristics.

Effects of Acorns on Meat Quality and Lipid Metabolism-Related Gene Expression in Muscle Tissues of Yuxi Black Pigs

Objectives: The aim of this study was to investigate the effects of acorn diets on the composition of fatty acid (FA) and the intramuscular fat (IMF) content in Yuxi black pigs. Methods: Ninety Yuxi black pigs with similar body weight (99.60 ± 2.32 kg) were randomly divided into five groups. The control group was fed a basal diet, and the AD20, AD30, AD40, and AD50 groups were fed experimental diets which contained 20%, 30%, 40%, and 50% acorns, respectively. The feeding experiment lasted for 120 days. Results: The results showed that compared with the control group, the content of SFA in longissimus dorsi and biceps femoris tissues in the AD30 group decreased by 8.57% and 20.10%, and the content of MUFA increased by 5.40% and 15.83%, respectively, while the PUFA content of biceps femoris increased by 5.40% (p &lt; 0.05). Meanwhile, the IMF content of the AD30 group was significantly higher than that of the control group in the longissimus dorsi and biceps femoris. In addition, the mRNA expression levels of the ATGL, PPARγ, and FABP4 genes in longissimus dorsi (p &lt; 0.05) were up-regulated, and HSL were down-regulated (p &lt; 0.05) in the AD30 group. In the biceps femoris of the AD30 group, it was observed that the expression levels of the ACC and FAS genes were up-regulated (p &lt; 0.05), while HSL and ATGL genes were down-regulated (p &lt; 0.05). Conclusions: These results demonstrated that the addition of appropriate amounts of acorn to the diet (a 30% acorn diet) could improve the nutritional value of pork.

Distinct characteristics of BTLA/HVEM axis expression on Tregs and its impact on the expansion and attributes of Tregs in patients with active pulmonary tuberculosis.

Pulmonary tuberculosis (PTB) remains one of the deadliest infectious diseases. Understanding PTB immunity is of potential value for exploring immunotherapy for treating chemotherapy-resistant PTB. CD4+CD25+Foxp3+ regulatory T cells (Tregs) are key players that impair immune responses to Mycobacteria tuberculosis (MTB). Currently, the intrinsic factors governing Treg expansion and influencing the immunosuppressive attributes of Tregs in PTB patients are far from clear. Here, we employed flow cytometry to determine the frequency of Tregs and the expression of B and T lymphocyte attenuator (BTLA) and its ligand, herpesvirus entry mediator (HVEM), on Tregs in patients with active PTB. Furthermore, the expression of conventional T cells and of programmed death-ligand 1 (PD-L1) and programmed death-1 (PD-1) on Tregs in patients with active PTB was determined. We then examined the characteristics of BTLA/HVEM expression and its correlation with Treg frequency and PD-L1 and PD-1 expression on Tregs in PTB patients. The frequency of Tregs was increased in PTB patients and it had a relevance to PTB progression. Intriguingly, the axis of cosignal molecules, BTLA and HVEM, were both downregulated on the Tregs of PTB patients compared with healthy controls (HCs), which was the opposite of their upregulation on conventional T cells. Unexpectedly, their expression levels were positively correlated with the frequency of Tregs, respectively. These seemingly contradictory results may be interpreted as follows: the downregulation of BTLA and HVEM may alleviate BTLA/HVEM cis-interaction-mediated coinhibitory signals pressing on naïve Tregs, helping their activation, while the BTLA/HVEM axis on effector Tregs induces a costimulatory signal, promoting their expansion. Certainly, the mechanism underlying such complex effects remains to be explored. Additionally, PD-L1 and PD-1, regarded as two of the markers characterizing the immunosuppressive attributes and differentiation potential of Tregs, were upregulated on the Tregs of PTB patients. Further analysis revealed that the expression levels of BTLA and HVEM were positively correlated with the frequency of PD-1+Tregs and PD-L1+Tregs, respectively. Our study illuminated distinct characteristics of BTLA/HVEM axis expression on Tregs and uncovered its impact on the expansion and attributes of Tregs in patients with active PTB. Therefore, blockade of the BTLA/HVEM axis may be a promising potential pathway to reduce Treg expansion for the improvement of anti-MTB immune responses.

N-Glycan Branching Regulates BTLA Opposite to PD-1 to Limit T Cell Hyperactivity Induced by Branching Deficiency.

N-glycan branching is a potent and multifaceted negative regulator of proinflammatory T cell and B cell function. By promoting multivalent galectin-glycoprotein lattice formation at the cell surface, branching regulates clustering and/or endocytosis of the TCR complex (TCR+CD4/CD8), CD45, CD25, BCR, TLR2 and TLR4 to inhibit T cell and B cell activation/proliferation and proinflammatory TH1 and TH17 over TH2 and induced T regulatory cell responses. In addition, branching promotes cell surface retention of the growth inhibitory receptor CTLA-4. However, the role of N-glycan branching in regulating cell surface levels of other checkpoint receptors such as BTLA (B and T lymphocyte attenuator) and PD-1 (programmed cell death protein 1) is unknown. In this study, we report that whereas branching significantly enhances PD-1 cell surface expression by reducing loss from endocytosis, the opposite occurs with BTLA in both T cells and B cells. T cell hyperactivity induced by branching deficiency was opposed by BTLA ligation proportional to increased BTLA expression. Other members of the BTLA/HVEM (herpesvirus entry mediator) signaling axis in T cells, including HVEM, LIGHT, and CD160, are largely unaltered by branching. Thus, branching-mediated endocytosis of BTLA is opposite of branching-induced inhibition of PD-1 endocytosis. In this manner, branching deficiency-induced upregulation of BTLA appears to serve as a checkpoint to limit extreme T cell hyperactivity and proinflammatory outcomes in T cells with low branching.

CD14 is a decision-maker between Fas-mediated death and inflammation

Signaling through classical death receptor Fas was mainly appreciated as a pro-death pathway until recent reports characterized pro-inflammatory outcomes of Fas-mediated activation in pathological contexts. How Fas signaling can switch to pro-inflammatory activation is poorly understood. Herein, we report that in macrophages and neutrophils, the Toll-like receptor (TLR) adapter CD14 determines the inflammatory output of Fas-mediated signaling. Our findings propose CD14 as a crucial chaperone of Fas receptor internalization in macrophages and neutrophils, resulting in Cd14-/- myeloid cells that are protected from FasL-induced apoptosis, activate nuclear factor κB (NF-κB), and release cytokines in response. As in TLR signaling, CD14 is also required for Fas to signal through the adaptor TRIF (TIR-domain-containing adapter-inducing interferon-β) and induce a pro-death complex. Our findings demonstrate that CD14 availability can determine the switch between Fas-mediated pro-death and pro-inflammatory outcomes by internalizing the receptor.

Chimeric Antigen Receptor T Cell Bearing Herpes Virus Entry Mediator Co-Stimulatory Signal Domain Exhibits Exhaustion-Resistant Properties.

Improving chimeric antigen receptor (CAR)-T cell therapeutic outcomes and expanding its applicability to solid tumors requires further refinement of CAR-T cells. We previously reported that CAR-T cells bearing a herpes virus entry mediator (HVEM)-derived co-stimulatory signal domain (CSSD) (HVEM-CAR-T cells) exhibit superior functions and characteristics. Here, we conducted comparative analyses to evaluate the impact of different CSSDs on CAR-T cell exhaustion. The results indicated that HVEM-CAR-T cells had significantly lower frequencies of exhausted cells and exhibited the highest proliferation rates upon antigenic stimulation. Furthermore, proliferation inhibition by programmed cell death ligand 1 was stronger in CAR-T cells bearing CD28-derived CSSD (CD28-CAR-T cells) whereas it was weaker in HVEM-CAR-T. Additionally, HVEM-CAR-T cells maintained a low exhaustion level even after antigen-dependent proliferation and exhibited potent killing activities, suggesting that HVEM-CAR-T cells might be less prone to early exhaustion. Analysis of CAR localization on the cell surface revealed that CAR formed clusters in CD28-CAR-T cells whereas uniformly distributed in HVEM-CAR-T cells. Analysis of CD3ζ phosphorylation indicated that CAR-dependent tonic signals were strongly sustained in CD28-CAR-T cells whereas they were significantly weaker in HVEM-CAR-T cells. Collectively, these results suggest that the HVEM-derived CSSD is useful for generating CAR-T cells with exhaustion-resistant properties, which could be effective against solid tumors.

Preservation of retinal structure and function in two mouse models of inherited retinal degeneration by ONL1204, an inhibitor of the Fas receptor

Due to the large number of genes and mutations that result in inherited retinal degenerations (IRD), there has been a paucity of therapeutic options for these patients. There is a large unmet need for therapeutic approaches targeting shared pathophysiologic pathways in a mutation-independent manner. The Fas receptor is a major activator and regulator of retinal cell death and inflammation in a variety of ocular diseases. We previously reported the activation of Fas-mediated photoreceptor (PR) cell death in two different IRD mouse models, rd10 and P23H, and demonstrated the protective effect of genetic Fas inhibition. The purpose of this study was to examine the effects of pharmacologic inhibition of Fas in these two models by intravitreal injection with a small peptide inhibitor of the Fas receptor, ONL1204. A single intravitreal injection of ONL1204 was given to one eye of rd10 mice at P14. Two intravitreal injections of ONL1204 were given to the P23H mice, once at P14 and again at 2-months of age. The fellow eyes were injected with vehicle alone. Fas activation, rate of PR cell death, retinal function, and the activation of immune cells in the retina were evaluated. In both rd10 and P23H mice, ONL1204 treatment resulted in decreased number of TUNEL (+) PRs, decreased caspase 8 activity, enhanced photoreceptor cell counts, and improved visual function compared with vehicle treated fellow eyes. Treatment with ONL1204 also reduced immune cell activation in the retinas of both rd10 and P23H mice. The protective effect of pharmacologic inhibition of Fas by ONL1204 in two distinct mouse models of retinal degeneration suggests that targeting this common pathophysiologic mechanism of cell death and inflammation represents a potential therapeutic approach to preserve the retina in patients with IRD, regardless of the genetic underpinning.

Clinical Significance of TNFSF14/LIGHT and CD160 in Gastric Cancer and Peptic Ulcer Dyspepsia.

Previous studies have reported the role of the Herpes Virus Entry Mediator (HVEM) in various cancer including gastric cancer. However, the expression level and clinical significance of CD160 and Tumor Necrosis Factor Ligand Superfamily Member 14 (TNFSF14) pathways in gastric cancer and gastric dyspepsia patients have remained unexplored. The study involved the collection of gastric tissue biopsies from 42 patients with non-ulcerative dyspepsia (NUD) as the control group, 43 gastric cancer (GC) patients, and 48 patients with peptic-ulcerative dyspepsia (PUD). All the patients were endoscopically examined at Imam Khomeini Hospital in Sari, Mazandaran, Iran. The expression levels of TNFSF14 and CD160 mRNA were assessed using quantitative real-time PCR (qPCR) with the SYBR Green method. Statistical analysis was performed to investigate the potential association between the clinical and experimental data. Among the 133 gastric endoscopic biopsies examined, LIGHT exhibited a significant overexpression in GC patients (p-value < 0.01). Moreover, the expression of TNFSF14 was higher in GC patients with stages I and II (p-value<0.05). Furthermore, GC patients with TNM stages III+IV were accompanied by high expression levels of LIGHT (p-value < 0.01) as well as CD160 (p-value<0.05). The expression of CD160 was also higher in younger adults with PUD (p-value<0.05). Whereas TNFSF14 exhibited higher expression in older adults with GC (p-value<0.05). Furthermore, this research provided insights into the potential biological pathways and significant gene enrichment of TNFSF14 and CD160, suggesting the potential role of CD160 and TNFSF14 in the regulation of immune system in GC and PUD. These findings suggest the possible role of LIGHT and CD160 expression in gastric cancer patients in immune dysregulation toward gastric cancer. Targeted immunotherapy that harnessing co-stimulatory molecules like LIGHT and CD160 could be a promising approach in the treatment of GC as well as potential GC tumor markers.

Multilayered Computational Framework for Designing Peptide Inhibitors of HVEM-LIGHT Interaction.

The herpesvirus entry mediator (HVEM) and its ligand LIGHT play crucial roles in immune system regulation, including T-cell proliferation, B-cell differentiation, and immunoglobulin secretion. However, excessive T-cell activation can lead to chronic inflammation and autoimmune diseases. Thus, inhibiting the HVEM-LIGHT interaction emerges as a promising therapeutic strategy for these conditions and in preventing adverse reactions in organ transplantation. This study focused on designing peptide inhibitors, targeting the HVEM-LIGHT interaction, using molecular dynamics (MD) simulations of 65 peptides derived from HVEM. These peptides varied in length and disulfide-bond configurations, crucial for their interaction with the LIGHT trimer. By simulating 31 HVEM domain variants, including the full-length protein, we assessed conformational changes upon LIGHT binding to understand the influence of HVEM segments and disulfide bonds on the binding mechanism. Employing multitrajectory microsecond-scale, all-atom MD simulations and molecular mechanics with generalized Born and surface area (MM-GBSA) binding energy estimation, we identified promising CRD2 domain variants with high LIGHT affinity. Notably, point mutations in these variants led to a peptide with a single disulfide bond (C58-C73) and a K54E substitution, exhibiting the highest binding affinity. The importance of the CRD2 domain and Cys58-Cys73 disulfide bond for interrupting HVEM-LIGHT interaction was further supported by analyzing truncated CRD2 variants, demonstrating similar binding strengths and mechanisms. Further investigations into the binding mechanism utilized steered MD simulations at various pulling speeds and umbrella sampling to estimate the energy profile of HVEM-based inhibitors with LIGHT. These comprehensive analyses revealed key interactions and different binding mechanisms, highlighting the increased binding affinity of selected peptide variants. Experimental circular dichroism techniques confirmed the structural properties of these variants. This study not only advances our understanding of the molecular basis of HVEM-LIGHT interactions but also provides a foundation for developing novel therapeutic strategies for immune-related disorders. Furthermore, it sets a gold standard for peptide inhibitor design in drug development due to its systematic approach.

Augmenting CAR T-cell Functions with LIGHT.

Chimeric antigen receptor (CAR) T-cell therapy has resulted in remarkable clinical success in the treatment of B-cell malignancies. However, its clinical efficacy in solid tumors is limited, primarily by target antigen heterogeneity. To overcome antigen heterogeneity, we developed CAR T cells that overexpress LIGHT, a ligand of both lymphotoxin-β receptor on cancer cells and herpes virus entry mediator on immune cells. LIGHT-expressing CAR T cells displayed both antigen-directed cytotoxicity mediated by the CAR and antigen-independent killing mediated through the interaction of LIGHT with lymphotoxin-β receptor on cancer cells. Moreover, CAR T cells expressing LIGHT had immunostimulatory properties that improved the cells' proliferation and cytolytic profile. These data indicate that LIGHT-expressing CAR T cells may provide a way to eliminate antigen-negative tumor cells to prevent antigen-negative disease relapse.

Preclinical Immunogenicity and Efficacy Studies for Therapeutic Vaccines for Human Papillomavirus-Type-16-Associated Cancer.

The objective of this study was to conduct preclinical immunogenicity and efficacy studies with several therapeutic vaccines for human papillomavirus (HPV)-16-associated cancers expressing the early antigens E5, E6, and E7 with or without E2. The viral oncoproteins were either expressed by themselves as fusion proteins or the fusion proteins were inserted genetically into herpes simplex virus (HSV)-1 glycoprotein D (gD) which, upon binding to the herpes virus entry mediator (HVEM), inhibits an early T cell checkpoint mediated by the B and T cell mediator (BTLA). This, in turn, lowers the threshold for T cell activation and augments and broadens CD8+ T cell responses to the antigens. The fusion antigens were expressed by chimpanzee adenovirus (AdC) vectors. Expression of the HPV antigens within gD was essential for vaccine immunogenicity and efficacy against challenge with TC-1 cells, which express E7 and E6 of HPV-16 but neither E5 nor E2. Unexpectedly, inclusion of E2 increased both CD8+ T cell responses to the other oncoproteins of HPV-16 and the effectiveness of the vaccines to cause the regression of sizable TC-1 tumors.

HVEM in acute lymphocytic leukemia facilitates tumour immune escape by inhibiting CD8+ T cell function.

Leukaemia remains a major contributor to global mortality, representing a significant health risk for a substantial number of cancer patients. Despite notable advancements in the field, existing treatments frequently exhibit limited efficacy or recurrence. Here, we explored the potential of abolishing HVEM (herpes virus entry mediator, TNFRSF14) expression in tumours as an effective approach to treat acute lymphoblastic leukaemia (ALL) and prevent its recurrence. The clinical correlations between HVEM and leukaemia were revealed by public data analysis. HVEM knockout (KO) murine T cell lymphoblastic leukaemia cell line EL4 were generated using CRISPR-Cas9 technology, and syngeneic subcutaneous tumour models were established to investigate the in vivo function of HVEM. Immunohistochemistry (IHC), RNA-seq and flow cytometry were used to analyse the tumour immune microenvironment (TIME) and tumour draining lymph nodes (dLNs). Immune functions were investigated by depletion of immune subsets in vivo and T cell functional assays in vitro. The HVEM mutant EL4 cell lines were constructed to investigate the functional domain responsible for immune escape. According to public databases, HVEM is highly expressed in patients with ALL and acute myeloid leukemia (AML) and is negatively correlated with patient prognosis. Genetic deletion of HVEM in EL4 cells markedly inhibited tumour progression and prolonged the survival of tumour-bearing mice. Our experiments proved that HVEM exerted its immunosuppressive effect by inhibiting antitumour function of CD8+ T cell through CRD1 domain both in vivo and in vitro. Additionally, we identified a combination therapy capable of completely eradicating ALL tumours, which induces immune memory toward tumour protection. Our study reveals the potential mechanisms by which HVEM facilitates ALL progression, and highlights HVEM as a promising target for clinical applications in relapsed ALL therapy.

Platelets Induce Cell Apoptosis of Cardiac Cells via FasL after Acute Myocardial Infarction.

Acute myocardial infarction (AMI) is one of the leading causes of death worldwide. Cell apoptosis in the myocardium plays an important role in ischemia and reperfusion (I/R) injury, leading to cardiac damage and dysfunction. Platelets are major players in hemostasis and play a crucial role in vessel occlusion, inflammation, and cardiac remodeling after I/R. Here, we studied the impact of platelets on cell apoptosis in the myocardium using a close-chest mouse model of AMI. We found caspase-3-positive resident cardiac cells, while leukocytes were negative for caspase-3. Using two different mouse models of thrombocytopenia, we detected a significant reduction in caspase-3 positive cells in the infarct border zone after I/R injury. Further, we identified platelet FasL to induce cell apoptosis via the extrinsic pathway of Fas receptor activation of target cells. Mechanistically, hypoxia triggers platelet adhesion to FasR, suggesting that platelet-induced apoptosis is elevated after I/R. Platelet-specific FasL knock-out mice showed reduced Bax and Bcl2 expression, suggesting that platelets modulate the intrinsic and extrinsic pathways of apoptosis, leading to reduced infarct size after myocardial I/R injury. Thus, a new mechanism for how platelets contribute to tissue homeostasis after AMI was identified that should be validated in patients soon.

Targeting BTLA with the peptide inhibitor HVEM(14-39) – A new way to restore the activity of T cells in melanoma

The complex of B- and T-lymphocyte attenuator (BTLA) and herpes virus entry mediator (HVEM) plays a critical role in immune regulation and has emerged as a promising therapeutic target for cancer treatment. In this study, we investigated the potential of the peptide inhibitor HVEM(14-39) to restore peripheral T cell activity in patients with advanced melanoma. In these patients, CD8+ T cells downregulated BTLA expression and increased HVEM expression upon activation. The addition of HVEM(14-39) reduced the percentage of BTLA+ CD8+ T cells and increased the subpopulation of HVEM+ CD8+ T cells. Additionally, HVEM(14-39) enhanced T cell activation, proliferation, and the shift toward effector memory T cell subpopulations. Finally, this peptide affected the proliferation rate and late apoptosis of melanoma cell line in co-culture with T cells. These findings suggest that HVEM(14-39) can overcome T cell exhaustion and improve antitumor responses. Peptide-based immunotherapy targeting the BTLA-HVEM complex offers a promising alternative to monoclonal antibody-based therapies, with the potential for fewer side effects and higher treatment efficacy.

Herpes virus entry mediator signaling blockade produces mortality in neonatal sepsis through induced cardiac dysfunction.

Sepsis remains a major source of morbidity and mortality in neonates, and characterization of immune regulation in the neonatal septic response remains limited. HVEM is a checkpoint regulator which can both stimulate or inhibit immune responses and demonstrates altered expression after sepsis. We hypothesized that signaling via HVEM would be essential for the neonatal response to sepsis, and that therefore blockade of this pathway would improve survival to septic challenge. To explore this, neonatal mice were treated with cecal slurry (CS), CS with Anti-HVEM antibody (CS-Ab) or CS with isotype (CS-IT) and followed for 7-day survival. Mice from all treatment groups had thymus, lung, kidney and peritoneal fluid harvested, weighed, and stained for histologic evaluation, and changes in cardiac function were assessed with echocardiography. Mortality was significantly higher for CS-Ab mice (72.2%) than for CS-IT mice (22.2%). CS resulted in dysregulated alveolar remodeling, but CS-Ab lungs demonstrated significantly less dysfunctional alveolar remodeling than CS alone (MCL 121.0 CS vs. 87.6 CS-Ab), as well as increased renal tubular vacuolization. No morphologic differences in alveolar septation or thymic karyorrhexis were found between CS-Ab and CS-IT. CS-Ab pups exhibited a marked decrease in heart rate (390.3 Sh vs. 342.1 CS-Ab), stroke volume (13.08 CS-IT vs. 8.83 CS-Ab) and ultimately cardiac output (4.90 Sh vs. 3.02 CS-Ab) as well as a significant increase in ejection fraction (73.74 Sh vs. 83.75 CS-Ab) and cardiac strain (40.74 Sh vs. 51.16 CS-Ab) as compared to CS-IT or Sham animals. While receptor ligation of aspects of HVEM signaling, via antibody blockade, appears to mitigate aspects of lung injury and thymic involution, stimulatory signaling via HVEM still seems to be necessary for vascular and hemodynamic resilience and overall neonatal mouse survival in response to this experimental polymicrobial septic insult. This dissonance in the activity of anti-HVEM neutralizing antibody in neonatal animals speaks to the differences in how septic cardiac dysfunction should be considered and approached in the neonatal population.

Abstract PO3-15-11: Soluble sFas, sFasL, sPD1, and sPD-L1 analyses in the blood peripheral of locally advanced breast cancer women before and after neoadjuvant chemotherapy

Abstract Assess soluble sFAS, sFASL, sPD1, and sPD-L1 levels in patients with HER2 or triple-negative (TN) breast cancer submitted to neoadjuvant chemotherapy. A prospective cohort study was performed with TN and HER2+ breast cancer patients between 2015 and 2018. Soluble levels of sFasL, sFas, sPD-L1, and sPD1 were collected before and after neoadjuvant chemotherapy (NAC). NAC regimens included a dense dose of Adriablastin and cyclophosphamide during four cycles, followed by Paclitaxel for 12 weeks. No clinical evidence of tumor in the breast and axillary lymph nodes was defined as a pathological complete response (pCR). Twenty-one women with TN (56,7%) and 16 (43,3%) HER2+ breast cancer were included. Twenty-one women (56.7%) presented complete pathological response (pCR) after neoadjuvant chemotherapy (NAC), defined as the absence of invasive disease in the breast and lymph nodes. High sPD1 and sFas levels in the TN and HER2+ patients compared to the control group (P&amp;lt; 0.05). In paired analysis, statistical differences of sFas and sFasL levels in TN and HER2+ patients before and after NAC (P&amp;lt; 0.05). Low levels of sPDL1 in HER2+ patients with pCR compared to non-pCR (P&amp;lt; 0.05). High sFasL levels in TN patients with pCR compared to the non-pCR group (P&amp;lt; 0.05). Conclusion: soluble sFas, sFas-L, sPD1, and sPD-L1 levels were apoptosis-related markers with potential predictive value of neoadjuvant chemotherapy response in TN and HER2+ breast cancer. Keywords: breast cancer; FAS receptor; Programmed death 1, HER2+, Triple negative Citation Format: Carolina Vasconcelos, Marcelo Salgado, Carlos Eduardo Anunciação, Denise Viana, Leuridan Torres, Nathália Valois Montarroyos de Moraes. Soluble sFas, sFasL, sPD1, and sPD-L1 analyses in the blood peripheral of locally advanced breast cancer women before and after neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-15-11.

Mangiferin, A Naturally Occurring Glucosylxanthone, Induces Apoptosis in Caco-2 Cells In Vitro and Exerts Protective Effects on Acetic Acid-Induced Ulcerative Colitis in Mice through the Regulation of NLRP3.

Inflammatory bowel diseases (IBD), an inflammatory disease, include Crohn's disease and ulcerative colitis. Dysregulated autoimmune response to gut dysbiosis is mainly involved in the pathogenesis of IBD and is triggered by various inciting environmental factors. With its rising prevalence in every continent, IBD has evolved into a global disease, which is on the rise, affecting people of all ages. There is a growing incidence of IBD in the elderly population, as evidenced by epidemiological data. IBD is characterized by an inflammatory process that requires a lifelong treatment. The main challenge in IBD management is the adverse side effects associated with almost all of the currently available drugs. Hence, there is a search for drugs with more efficacy and fewer side effects. Natural products with great structural diversity and ease of modification chemically are being explored, as they were shown to control IBD by safely suppressing pro-inflammatory pathways. The present study aims at understanding the role of mangiferin, a COX-2 inhibitor isolated from tubers of Pueraria tuberosa in the treatment of IBD and colon cancer, in vitro on the Caco-2 human colon cancer cell line and in vivo in the acetic acid-induced IBD mouse model. In the acetic acid-induced colitis model, it prevented the decrease in length of the colon, mucosal erosion, and cellular infiltration in a dose-dependent manner. The expression levels of various pro-inflammatory markers like COX-2, IL1β, TNF-α, INF-γ, IL-6, NLRP3, and caspase-1 were downregulated in an acetic acid-induced mouse model on treatment with mangiferin in a dose dependent manner. Mangiferin also showed anticancer effects on Caco-2 cells by increasing the expression of Fas ligand, Fas receptor, FADD, caspase-8, and caspase-3 proteins, whereas Bid and Bcl-2 proteins showed decreased expression. These data suggest that mangiferin, an inhibitor of COX, induces apoptosis in colon cancer cells in vitro and protects mice from acetic acid-induced colitis in vivo.

Herpesvirus Entry Mediator as an Immune Checkpoint Target and a Potential Prognostic Biomarker in Myeloid and Lymphoid Leukemia.

Herpesvirus entry mediator (HVEM) is a molecular switch that can modulate immune responses against cancer. The significance of HVEM as an immune checkpoint target and a potential prognostic biomarker in malignancies is still controversial. This study aims to determine whether HVEM is an immune checkpoint target with inhibitory effects on anti-tumor CD4+ T cell responses in vitro and whether HVEM gene expression is dysregulated in patients with acute lymphocytic leukemia (ALL). HVEM gene expression in tumor cell lines and peripheral blood mononuclear cells (PBMCs) from ALL patients and healthy controls was measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Tumor cells were left untreated (control) or were treated with an HVEM blocker before co-culturing with CD4+ T cells in vitro in a carboxyfluorescein succinimidyl ester (CFSE)-dependent proliferation assay. HVEM expression was upregulated in the chronic myelogenous leukemia cell line (K562) (FC = 376.3, p = 0.086) compared with normal embryonic kidney cells (Hek293). CD4+ T cell proliferation was significantly increased in the HVEM blocker-treated K562 cells (p = 0.0033). Significant HVEM differences were detected in ALL PBMCs compared with the controls, and these were associated with newly diagnosed ALL (p = 0.0011) and relapsed/refractory (p = 0.0051) B cell ALL (p = 0.0039) patients. A significant differentiation between malignant ALL and the controls was observed in a receiver operating characteristic (ROC) curve analysis with AUC = 0.78 ± 0.092 (p = 0.014). These results indicate that HVEM is an inhibitory molecule that may serve as a target for immunotherapy and a potential ALL biomarker.

B- and T-Lymphocyte Attenuator in Systemic Lupus Erythematosus Disease Pathogenesis.

B- and T-lymphocyte attenuator (BTLA; CD272) is an immunoglobulin superfamily member and part of a family of checkpoint inhibitory receptors that negatively regulate immune cell activation. The natural ligand for BTLA is herpes virus entry mediator (HVEM; TNFRSF14), and binding of HVEM to BTLA leads to attenuation of lymphocyte activation. In this study, we evaluated the role of BTLA and HVEM expression in the pathogenesis of systemic lupus erythematosus (SLE), a multisystem autoimmune disease. Peripheral blood mononuclear cells from healthy volunteers (N = 7) were evaluated by mass cytometry by time-of-flight to establish baseline expression of BTLA and HVEM on human lymphocytes compared with patients with SLE during a self-reported flare (N = 5). High levels of BTLA protein were observed on B cells, CD4+, and CD8+ T cells, and plasmacytoid dendritic cells in healthy participants. HVEM protein levels were lower in patients with SLE compared with healthy participants, while BTLA levels were similar between SLE and healthy groups. Correlations of BTLA-HVEM hub genes' expression with patient and disease characteristics were also analyzed using whole blood gene expression data from patients with SLE (N = 1,760) and compared with healthy participants (N = 60). HVEM, being one of the SLE-associated genes, showed an exceptionally strong negative association with disease activity. Several other genes in the BTLA-HVEM signaling network were strongly (negative or positive) correlated, while BTLA had a low association with disease activity. Collectively, these data provide a clinical rationale for targeting BTLA with an agonist in SLE patients with low HVEM expression.