Interferon Gene Signature Research Articles

Interplay between Two Paralogous Human Silencing Hub (HuSH) Complexes in Regulating LINE-1 Element Silencing

The Human Silencing Hub (HuSH) complex silences retrotransposable elements in vertebrates. Here, we identify a second HuSH complex, designated HuSH2, which is centered around TASOR2, a paralog of the core TASOR protein in HuSH. Our findings reveal that HuSH and HuSH2 localize to distinct and non-overlapping genomic loci. Specifically, HuSH localizes to and represses LINE-1 retrotransposons, whereas HuSH2 targets and represses KRAB-ZNFs and interferon signaling and response genes. We use in silico protein structure predictions to simulate MPP8 interactions with TASOR paralogs, guiding amino acid substitutions that disrupted binding to HuSH complexes. These MPP8 transgenes and other constructs reveal the importance of HuSH complex quantities in regulating LINE-1 activity. Furthermore, our results suggest that dynamic changes in TASOR and TASOR2 expression enable cells to finely tune HuSH-mediated silencing. This study offers insights into the interplay of HuSH complexes, highlighting their vital role in retrotransposon regulation.

OA25 Not so “savy” afterall

Abstract Introduction Interferonopathies (IFN’s) are a constellation of diseases that cause recurrent pathogenic inflammation, arising primarily through antigen-independent hyperactivation of immune pathways¹. It is primarily due to abnormal production or signalling of type I IFNs². A disorder of both the innate and adaptive immune system, this condition is relatively new with the term only coined in 2011. Currently there are more than 20 interferonopathies recognized, with new interferonopathies being identified like Sting associated vasculopathy with onset in infancy (SAVI). Case description Our patient first presented with a severe panniculitis rash, Raynaud’s, swelling of her limbs and hepatosplenomegaly at five weeks of age. She developed significant respiratory distress requiring non-invasive ventilation. A CT Thorax revealed diffuse groundglass opacification suggestive of interstitial lung disease. She had elevated inflammatory markers (CRP 24 mg/L, ferritin 1448 ng/ml, ESR 88 mm/hr), a transaminitis (ALT 193 U/ml, AST 356 U/L). She had multiple positive auto antibodies (Table 1) Clinically SAVI was suspected as the most likely diagnosis. Her interferon signature gene assay demonstrated exaggerated IFI 27 and IFI44L levels. A Trio exome sequencing and IKBKG sequencing however have not been indicative of any currently recognised interferonopathy. Further genetic analysis has been requested to explore possible novel pathogenic mutations. A reasonable clinical response was seen with corticosteroid therapy in combination with Jak Inhibition. With worsening of her cutaneous disease and an increasing need for corticosteroid use a trial of anti IL-6 therapy was initiated. This was subsequently discontinued when she presented with severe acute digital ischemia. It was managed with escalating doses of ruxolitinib, pulse high dose corticosteroids and epoprostenol infusion. Her interferon signature gene assay demonstrated exaggerated IFI 27 and IFI44L levels. A Trio exome sequencing and Inhibitor of nuclear factor kappa B gene (IKBKG) sequencing however have not been indicative of any currently recognised interferonopathy. Further genetic analysis has been requested to explore possible novel pathogenic mutations. A reasonable clinical response was seen with corticosteroid therapy in combination with Jak Inhibition. With worsening of her cutaneous disease and an increasing need for corticosteroid use a trial of anti IL-6 therapy was initiated. This was subsequently discontinued when she presented with severe acute digital ischemia. It was managed with escalating doses of ruxolitinib, pulse high dose corticosteroids and epoprostenol infusion. Discussion This case enhances our current understanding of interferonopathies. Although the phenotype and course of the disease is compatible with SAVI³, genetic testing is negative to date. Presently there are eleven heterozygous gain-of-function (GoF) variants for SAVI4. With JAK inhibition as the most successful therapeutic option to date5. Our case possibly represents an as yet unreported genetic variant, further studies are awaited.This case enhances our current understanding of interferonopathies. Although the phenotype and course of the disease is compatible with SAVI³, genetic testing is negative to date. Presently there are eleven heterozygous gain-of-function (GoF) variants for SAVI4. With JAK inhibition as the most successful therapeutic option to date5. Our case possibly represents an as yet unreported genetic variant, further studies are awaited.This case enhances our current understanding of interferonopathies. Although the phenotype and course of the disease is compatible with SAVI³, genetic testing is negative to date. Presently there are eleven heterozygous gain-of-function (GoF) variants for SAVI4. With JAK inhibition as the most successful therapeutic option to date5. Our case possibly represents an as yet unreported genetic variant, further studies are awaited. Key learning points • Early suspicion for an interferonopathy in very young infants with interstitial lung disease • Expanding the potentially new genetic variants of this condition • Challenge of treatment management

Metabolic dysfunction-associated steatohepatitis reduces interferon and macrophage liver gene signatures in patients with chronic hepatitis B

Background & AimsChronic HBV patients with concomitant metabolic dysfunction-associated steatohepatitis (MASH) have been shown to develop more advanced fibrosis faster with more severe liver disease as compared to patients with chronic HBV alone. However, our understanding of the underlying mechanisms is limited. Here we study how MASH co-morbidity impact immune activity in the liver of patients with chronic HBV infection. MethodsBulk RNA sequencing was performed on liver biopsies from patients with only MASH (n=10), only HBeAg-negative chronic HBV (ENEG; n=11), combined MASH/ENEG (n=9) and healthy controls (n=9). Biopsies with no or minimal fibrosis (≤F2) were selected to avoid confounding effects of fibrosis. We compared whole transcriptome data from patients with MASH/ENEG to those with ENEG alone to determine the impact of MASH co-morbidity on chronic hepatitis B. ResultsThere is a high degree of overlap of liver gene expression profiles in patients with only ENEG versus those with only MASH compared to healthy controls, suggesting a largely shared mechanism of liver dysfunction and immune activity for these distinct conditions. In patients with ENEG, MASH co-morbidity significantly reduced interferon pathway activity (NES=2.03, p.adj=0.0251), the expression of ISGs (e.g., IFIT2, IFI27, IFITM1, IFI6), and macrophage gene signatures (e.g., MARCO, CD163, CD5L, CD63), when compared to patients with ENEG alone. ConclusionsTranscriptomic profiling of the liver suggests that MASH negatively impacts ISGs expression in the liver of patients with ENEG, which may affect antiviral immune pathways, viral replication and inflammatory responses resulting in an increased risk of advanced fibrosis in patients with chronic hepatitis B. Our study provides valuable insights for guiding future research aimed at developing effective, tailored strategies for managing patients with both conditions. Impact and implicationsIn recent decades, obesity and associated health issues have reached epidemic levels, with steatotic liver disease affecting up to 30% of adults in developed countries, and this trend is also observed among chronic hepatitis B patients. Given the high and rising prevalence of steatotic liver disease and its frequent co-occurrence in chronic hepatitis B patients, it is essential to understand how conditions such as metabolic dysfunction-associated steatohepatitis (MASH) impact immune responses in the liver. This study provides unique insights into the impact of MASH on HBV antiviral immune activity in the liver of patients with chronic hepatitis B. The rising number of patients with both conditions affects treatment outcomes and highlights the urgent need for novel, tailored therapeutic strategies. Our study holds significant relevance for guiding future research on developing treatment strategies for patients with both MASH and chronic hepatitis B.

Shared neutrophil and T cell dysfunction is accompanied by a distinct interferon signature during severe febrile illnesses in children

Severe febrile illnesses in children encompass life-threatening organ dysfunction caused by diverse pathogens and other severe inflammatory syndromes. A comparative approach to these illnesses may identify shared and distinct features of host immune dysfunction amenable to immunomodulation. Here, using immunophenotyping with mass cytometry and cell stimulation experiments, we illustrate trajectories of immune dysfunction in 74 children with multi-system inflammatory syndrome in children (MIS-C) associated with SARS-CoV-2, 30 with bacterial infection, 16 with viral infection, 8 with Kawasaki disease, and 42 controls. We explore these findings in a secondary cohort of 500 children with these illnesses and 134 controls. We show that neutrophil activation and apoptosis are prominent in multi-system inflammatory syndrome, and that this is partially shared with bacterial infection. We show that memory T cells from patients with multi-system inflammatory syndrome and bacterial infection are exhausted. In contrast, we show viral infection to be characterized by a distinct signature of decreased interferon signaling and lower interferon receptor gene expression. Improved understanding of immune dysfunction may improve approaches to immunomodulator therapy in severe febrile illnesses in children.

Distinct Variations in Gene Expression and Cell Composition across Lichen Planus Subtypes.

Lichen planus (LP) is a highly prevalent inflammatory skin disease. While various clinical subtypes have been defined, detailed comparisons of these variants are lacking. This study aimed to elucidate differences in gene expression and cellular composition across LP subtypes. Lesional skin biopsies from 28 LP patients (classical, oral, genital, and lichen planopilaris) and seven non-diseased skin controls (NDC) were analyzed. Gene expression profiling of 730 inflammation-related genes was conducted using NanoString. Immune cell compositions were assessed by multiplex immunohistochemistry. Gene expression profiles revealed unique inflammatory signatures for each LP subtype. Lichen planopilaris exhibited the most divergence, with downregulated gene expression and upregulation of complement pathway genes (C5-7), along with elevated M2 macrophages. Oral and genital LP demonstrated similar profiles with strong upregulation of TNF-related and Toll-like receptor-associated genes. Oral LP showed the highest upregulation of cytotoxicity-associated genes, as well as high numbers of CD8+ IL-17A+ (Tc17) cells (8.02%). Interferon gene signatures were strongly upregulated in oral and classical LP. The study highlights distinct differences in inflammatory gene expression and cell composition across LP subtypes, emphasizing the need for tailored therapeutic approaches.

Safety, pharmacokinetics, biomarker response and efficacy of E6742: a dual antagonist of Toll-like receptors 7 and 8, in a first in patient, randomised, double-blind, phase I/II study in systemic lupus erythematosus

ObjectivesTo evaluate the safety, tolerability, pharmacokinetics (PK), biomarker response and efficacy of E6742 in a phase I/II study in patients with systemic lupus erythematosus (SLE).MethodsTwo sequential cohorts of patients with...

The assembly of neutrophil inflammasomes during COVID-19 is mediated by type I interferons.

The severity of COVID-19 is linked to excessive inflammation. Neutrophils represent a critical arm of the innate immune response and are major mediators of inflammation, but their role in COVID-19 pathophysiology remains poorly understood. We conducted transcriptomic profiling of neutrophils obtained from patients with mild and severe COVID-19, as well as from SARS-CoV-2 infected mice, in comparison to non-infected healthy controls. In addition, we investigated the inflammasome formation potential in neutrophils from patients and mice upon SARS-CoV-2 infection. Transcriptomic analysis of polymorphonuclear cells (PMNs), consisting mainly of mature neutrophils, revealed a striking type I interferon (IFN-I) gene signature in severe COVID-19 patients, contrasting with mild COVID-19 and healthy controls. Notably, low-density granulocytes (LDGs) from severe COVID-19 patients exhibited an immature neutrophil phenotype and lacked this IFN-I signature. Moreover, PMNs from severe COVID-19 patients showed heightened nigericin-induced caspase1 activation, but reduced responsiveness to exogenous inflammasome priming. Furthermore, IFN-I emerged as a priming stimulus for neutrophil inflammasomes. These findings suggest a potential role for neutrophil inflammasomes in driving inflammation during severe COVID-19. Altogether, these findings open promising avenues for targeted therapeutic interventions to mitigate the pathological processes associated with the disease.

Non-endothelial expression of endomucin in the mouse and human choroid

Endomucin (EMCN) is a 261 amino acid transmembrane glycoprotein that is highly expressed by venous and capillary endothelial cells where it plays a role in VEGF-mediated angiogenesis and regulation of immune cell recruitment. However, it is better known as a histological marker, where it has become widespread due to the commercial availability of high-quality antibodies that work under a wide range of conditions and in many tissues. The specificity of EMCN staining has been well-validated in retinal vessels, but while it has been used extensively as a marker in other tissues of the eye, including the choroid, the pattern of expression has not been described in detail. Here, in addition to endothelial expression in the choriocapillaris and deeper vascular layers, we characterize a population of EMCN-positive perivascular cells in the mouse choroid that did not co-localize with cells expressing other endothelial markers such as PECAM1 or PODXL. To confirm that these cells represented a new population of EMCN-expressing stromal cells, we then performed single cell RNA sequencing in choroids from adult wild-type mice. Analysis of this new dataset confirmed that, in addition to endothelial cells, Emcn mRNA expression was present in choroidal pericytes and a subset of fibroblasts, but not vascular smooth muscle cells. Besides Emcn, no known endothelial gene expression was detected in these cell populations, confirming that they did not represent endothelial-stromal doublets, a common technical artifact in single cell RNA seq datasets. Instead, choroidal Emcn-expressing fibroblasts exhibited high levels of chemokine and interferon signaling genes, while Emcn-negative fibroblasts were enriched in genes encoding extracellular matrix proteins. Emcn expressing fibroblasts were also detected in published datasets from mouse brain and human choroid, suggesting that stromal Emcn expression was not unique to the choroid and was evolutionarily conserved. Together, these findings highlight unique fibroblast and pericyte populations in the choroid and provide new context for the role of EMCN in the eye.

Heterozygous de novo dominant negative mutation of REXO2 results in interferonopathy

Mitochondrial RNA (mtRNA) in the cytosol can trigger the innate immune sensor MDA5, and autoinflammatory disease due to type I IFN. Here, we show that a dominant negative mutation in the gene encoding the mitochondrial exonuclease REXO2 may cause interferonopathy by triggering the MDA5 pathway. A patient characterized by this heterozygous de novo mutation (p.T132A) presented with persistent skin rash featuring hyperkeratosis, parakeratosis and acanthosis, with infiltration of lymphocytes and eosinophils around small blood vessels. In addition, circulating IgE levels and inflammatory cytokines, including IFNα, are found consistently elevated. Transcriptional analysis highlights a type I IFN gene signature in PBMC. Mechanistically, REXO2 (T132A) lacks the ability to cleave RNA and inhibits the activity of wild-type REXO2. This leads to an accumulation of mitochondrial dsRNA in the cytosol, which is recognized by MDA5, leading to the associated type I IFN gene signature. These results demonstrate that in the absence of appropriate regulation by REXO2, aberrant cellular nucleic acids may accumulate and continuously trigger innate sensors, resulting in an inborn error of immunity.

The Role of IRF9 Upregulation in Modulating Sensitivity to Olaparib and Platinum-Based Chemotherapies in Breast Cancer.

Poly(ADP-ribose) polymerase (PARP) inhibitors are targeted therapies that accumulate DNA damage by interfering with DNA repair mechanisms and are approved for treating several cancers with BRCA1/2 mutations. In this study, we utilized CRISPR-dCas9 interference screening to identify genes regulating sensitivity to PARP inhibitors in breast cancer cell lines. Our findings indicated that the interferon (IFN) signaling gene IRF9 was critically involved in modulating sensitivity to these inhibitors. We revealed that the loss of IRF9 leads to increased resistance to the PARP inhibitor in MDA-MB-468 cells, and a similar desensitization was observed in another breast cancer cell line, MDA-MB-231. Further analysis indicated that while the basal expression of IRF9 did not correlate with the response to the PARP inhibitor olaparib, its transcriptional induction was significantly associated with increased sensitivity to the DNA-damaging agent cisplatin in the NCI-60 cell line panel. This finding suggests a mechanistic link between IRF9 induction and cellular responses to DNA damage. Additionally, data from the METABRIC patient tissue study revealed a complex network of IFN-responsive gene expressions postchemotherapy, with seven upregulated genes, including IRF9, and three downregulated genes. These findings underscore the intricate role of IFN signaling in the cellular response to chemotherapy. Collectively, our CRISPR screening data and subsequent bioinformatic analyses suggest that IRF9 is a novel biomarker for sensitivity to DNA-damaging agents, such as olaparib and platinum-based chemotherapeutic agents. Our findings for IRF9 not only enhance our understanding of the genetic basis of drug sensitivity, but also elucidate the role of IRF9 as a critical effector within IFN signaling pathways, potentially influencing the association between the host immune system and chemotherapeutic efficacy.

Flying‐Saucer‐Shaped Nanoheterojunctions with Enhanced Colorectal Tumor Accumulation for Increased Oxidative Stress and Immunometabolic Regulation

AbstractThe treatment outcomes of nanomedicines against colorectal cancer are severely restricted by their insufficient accumulation in the tumor tissues, unsatisfactory antitumor effect, and weak immunometabolic modulation. To address these issues, flying‐saucer‐shaped nanoheterojunctions by coating copper oxide (CuxO) onto the surface of PEGylated zinc oxide (ZnO) nanoparticles are constructed. When exposed to ultrasound, the resultant CuxO@ZnO nanoheterojunctions exhibit increased locomotor activities, facilitating colorectal mucus infiltration, deep tumor penetration, and tumor cell internalization. The decoration of CuxO suppresses the rapid recombination of electrons and holes in CuxO@ZnO exposed to ultrasound, promoting the production of singlet oxygen and hydroxyl radical, which are generated by CuxO through a Fenton‐like chemodynamic reaction and CuxO@ZnO through sonodynamic reaction. After rectal administration, the sono‐chemodynamic CuxO@ZnO plus PD‐L1 antibodies effectively inhibit the growth of orthotopic and distant tumors. It elicits immunometabolic responses by inducing immunogenic cell death, activating the interferon genes signaling pathway stimulator, and inhibiting glucose transport and the glycolytic signaling pathways. This combined modality also increases the proportion of beneficial microbes (e.g., Bifidobacterium) and decreases the abundance of harmful microorganisms (e.g., Romboutsia) in the intestine. This treatment modality (CuxO@ZnO plus ultrasound and PD‐L1 antibodies) is a promising strategy for the synergistic treatment of colorectal cancer.

Ocular Tuberculosis Diagnosis Through Biomarkers: Clinical Relevance of Serum C1q and Whole Blood Interferon Gene Signature Score

ABSTRACT Purpose To assess the clinical relevance of pathophysiology-based biomarkers, specifically serum C1q and whole blood interferon gene signature score (IGSS), in ocular tuberculosis (OTB) diagnosis by conducting an integrative analysis of clinical presentations and treatment response. Methods This retrospective cohort study analysed data from 70 patients with suspected OTB at a tertiary care uveitis practice in Indonesia. Serum C1q levels and whole blood IGSS were quantified. Patients were categorized into four quadrants based on their biomarker profiles: quadrant 1 (high C1q & low IGSS), quadrant 2 (high C1q & high IGSS), quadrant 3 (low C1q & high IGSS), and quadrant 4 (low C1q & low IGSS). Characteristics of clinical presentations, work-up results, and treatment outcomes were explored according to the predefined quadrants. Results We identified that the majority of OTB patients diagnosed with concurrent active pulmonary TB were in quadrant 1, 2, or 3 (20/23, 87.0%). Twenty-seven patients (27/47, 57.4%) with clinically undifferentiated uveitis were in quadrant 4 (p < 0.001). Among patients in quadrants 1, 2, and 3, completion of a full course of antitubercular treatment (ATT) was associated with a lower number of patients showing persistence or recurrence of ocular inflammation compared to those who were not fully treated with ATT (14.3% vs 85.7%, p = 0.001). Conclusions Based on the analysis of clinical features and treatment outcomes, patients with elevated levels of either or both serum C1q and whole blood IGSS may reflect active TB disease in the eye, necessitating full ATT management.

PSMD11 loss-of-function variants correlate with a neurobehavioral phenotype, obesity, and increased interferon response

Primary proteasomopathies have recently emerged as a new class of rare early-onset neurodevelopmental disorders (NDDs) caused by pathogenic variants in the PSMB1, PSMC1, PSMC3, or PSMD12 proteasome genes. Proteasomes are large multi-subunit protein complexes that maintain cellular protein homeostasis by clearing ubiquitin-tagged damaged, misfolded, or unnecessary proteins. In this study, we have identified PSMD11 as an additional proteasome gene in which pathogenic variation is associated with an NDD-causing proteasomopathy. PSMD11 loss-of-function variants caused early-onset syndromic intellectual disability and neurodevelopmental delay with recurrent obesity in 10 unrelated children. Our findings demonstrate that the cognitive impairment observed in these individuals could be recapitulated in Drosophila melanogaster with depletion of the PMSD11 ortholog Rpn6, which compromised reversal learning. Our investigations in subject samples further revealed that PSMD11 loss of function resulted in impaired 26S proteasome assembly and the acquisition of a persistent type I interferon (IFN) gene signature, mediated by the integrated stress response (ISR) protein kinase R (PKR). In summary, these data identify PSMD11 as an additional member of the growing family of genes associated with neurodevelopmental proteasomopathies and provide insights into proteasomal biology in human health.

Development of EBV Related Diffuse Large B-cell Lymphoma in Deficiency of Adenosine Deaminase 2 with Uncontrolled EBV Infection

Deficiency of Adenosine Deaminase 2 (DADA2) patients presenting with primary immunodeficiency are at risk of uncontrolled EBV infection and secondary malignancies including EBV-related lymphoproliferative disorders (LPD). This paper describes the first case of EBV related diffuse large B-cell lymphoma in a patient with DADA2 and uncontrolled EBV infection. Consideration should be given to monitoring for EBV viraemia and to preventative EBV specific therapy in DADA2 and patients with at risk primary immunodeficiencies. A type I interferon (IFN) gene signature is associated with DADA2 though its association with immune dysregulation is unclear.

The role of the microscopic world: Exploring the role and potential of intratumoral microbiota in cancer immunotherapy.

Microorganisms, including bacteria, viruses, and fungi, coexist in the human body, forming a symbiotic microbiota that plays a vital role in human health and disease. Intratumoral microbial components have been discovered in various tumor tissues and are closely linked to the occurrence, progression, and treatment results of cancer. The intratumoral microbiota can enhance antitumor immunity through mechanisms such as activating the stimulator of interferon genes signaling pathway, stimulating T and NK cells, promoting the formation of TLS, and facilitating antigen presentation. Conversely, the intratumoral microbiota might suppress antitumor immune responses by increasing reactive oxygen species levels, creating an anti-inflammatory environment, inducing T cell inactivation, and enhancing immune suppression, thereby promoting cancer progression. The impact of intratumoral microbiota on antitumor immunity varies based on microbial composition, interactions with cancer cells, and the cancer's current state. A deep understanding of the complex interactions between intratumoral microbiota and antitumor immunity holds the potential to bring new therapeutic strategies and targets to cancer immunotherapy.

SFTSV nucleoprotein mediates DNA sensor cGAS degradation to suppress cGAS-dependent antiviral responses.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne RNA virus that is widespread in East and Southeast Asian countries with a high fatality rate of up to 30%. Up to now, many cytoplasmic pattern recognition receptors, such as RIG-I, MDA5, and SAFA, have been reported to recognize SFTSV genomic RNA and trigger interferon-dependent antiviral responses. However, current knowledge is not clear whether SFTSV can be recognized by DNA sensor cyclic GMP-AMP synthase (cGAS). Our study demonstrated that cGAS could recognize SFTSV infection via ectopic mitochondrial DNA, and the activated cGAS-stimulator of interferon genes signaling pathway could significantly inhibit SFTSV replication. Importantly, we further uncovered a novel mechanism of SFTSV to inhibit innate immune responses by the degradation of cGAS. cGAS was degraded in N-induced autophagy. Collectively, this study illustrated a novel virulence factor of SFTSV to suppress innate immune responses through autophagy-dependent cGAS degradation.

Human NLRC4 expression promotes cancer survival and associates with type I interferon signaling and immune infiltration.

The immune system can control cancer progression. However, even though some innate immune sensors of cellular stress are expressed intrinsically in epithelial cells, their potential role in cancer aggressiveness and subsequent overall survival in humans is mainly unknown. Here, we show that nucleotide-binding oligomerization domain-like receptor (NLR) family CARD domain-containing 4 (NLRC4) is downregulated in epithelial tumor cells of patients with colorectal cancer (CRC) by using spatial tissue imaging. Strikingly, only the loss of tumor NLRC4, but not stromal NLRC4, was associated with poor immune infiltration (mainly DCs and CD4+ and CD8+ T cells) and accurately predicted progression to metastatic stage IV and decrease in overall survival. By combining multiomics approaches, we show that restoring NLRC4 expression in human CRC cells triggered a broad inflammasome-independent immune reprogramming consisting of type I interferon (IFN) signaling genes and the release of chemokines and myeloid growth factors involved in the tumor infiltration and activation of DCs and T cells. Consistently, such reprogramming in cancer cells was sufficient to directly induce maturation of human DCs toward a Th1 antitumor immune response through IL-12 production in vitro. In multiple human carcinomas (colorectal, lung, and skin), we confirmed that NLRC4 expression in patient tumors was strongly associated with type I IFN genes, immune infiltrates, and high microsatellite instability. Thus, we shed light on the epithelial innate immune sensor NLRC4 as a therapeutic target to promote an efficient antitumor immune response against the aggressiveness of various carcinomas.

Patients with STAT1 Gain-of-function Mutations Display Increased Apoptosis which is Reversed by the JAK Inhibitor Ruxolitinib

IntroductionThe signal transducer and activator of transcription (STAT1) gain-of-function (GOF) syndrome accounts for most cases of chronic mucocutaneous candidiasis but is characterized by a broader clinical phenotype that may include bacterial, viral, or invasive fungal infections, autoimmunity, autoinflammatory manifestations, vascular complications, or malignancies. The severity of lymphopenia may vary and influence the infectious morbidity.MethodsIn our cohort of seven STAT1-GOF patients, we investigated the mechanisms that may determine T lymphopenia, we characterized the interferon gene signature (IGS) and analyzed the effect of ruxolitinib in reverting the immune dysregulation.ResultsSTAT1-GOF patients exhibited increased T lymphocyte apoptosis that was significantly augmented in both resting conditions and following stimulation with mitogens and IFNα, as evaluated by flow cytometry by Annexin V/ Propidium iodide assay. The JAK inhibitor ruxolitinib significantly reduced the IFNα-induced hyperphosphorylation of STAT1 and reverted the stimulation-induced T-cell apoptosis, in vitro. In two adult STAT1-GOF patients, the JAKinib treatment ameliorated chronic mucocutaneous candidiasis and lymphopenia. Most STAT1-GOF patients, particularly those who had autoimmunity, presented increased IGS that significantly decreased in the two patients during ruxolitinib treatment.ConclusionIn STAT1-GOF patients, T lymphocyte apoptosis is increased, and T lymphopenia may determine higher risk of severe infections. The JAKinib target therapy should be evaluated to treat severe chronic candidiasis and lymphopenia, and to downregulate the IFNs in patients with autoinflammatory or autoimmune manifestations.

Abstract 6159: Single cell analysis of circulating peripheral blood mononuclear cells in African American men with prostate cancer and their association with lethal disease

Abstract Prostate cancer is a leading cause of cancer-related deaths among men in the United States and affects African American (AA) men more so than other men. We and others previously described a distinct tumor immunobiology in AA prostate cancer patients. Furthermore, we discovered a serum proteome-defined suppression of tumor immunity signature that is prevalent among these patients and associated with lethal prostate cancer. In the current study, we sought to investigate the composition of circulating peripheral blood mononuclear cells (PBMCs) in AA and European American (EA) prostate cancer patients and their association with patient group and lethal prostate cancer. We obtained high-quality RNA-sequencing data for 277336 single cells representing circulating PBMCs from 59 AA and EA men. In the analysis, being an AA patients associated with an increased abundance of exhausted T cells, higher numbers of plasma B cells and CD16+ monocytes. Gene signatures indicative of T cell exhaustion and Treg activity were generally elevated in AA PBMCs while T cell effector function features were decreased. Within the overall cell population, interferon gene signatures were robustly elevated in AA than EA patients. This gene signature pattern that we observed in AA patients also associated with lethal prostate cancer, namely the T cell exhaustion, Treg activity and elevated interferon signaling gene signatures, may contribute to immune dysfunction and immune injury; pointing to potential clinical implications. Lastly, the interferon-induced transmembrane protein (IFITM3), interferon alpha inducible protein (IFI6), cysteine rich protein-1 (CRIP1), and the RAC family small GTPase2 (RAC2) were notably upregulated in AA patient-derived immune cells. In summary, we show that circulating immune cell populations and the associated gene signatures differ between men of African and European descent. Those elevated in AA patients correlated with lethal prostate cancer. Citation Format: Md Shakir Uddin Ahmed, Tiffany Dorsey, Stefan Ambs. Single cell analysis of circulating peripheral blood mononuclear cells in African American men with prostate cancer and their association with lethal disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6159.

Co-inhibition of TGF-β and PD-L1 pathways in a metastatic colorectal cancer mouse model triggers interferon responses, innate cells and T cells, alongside metabolic changes and tumor resistance

ABSTRACT Colorectal cancer (CRC) is the third most prevalent cancer worldwide with a high mortality rate (20–30%), especially due to metastasis to adjacent organs. Clinical responses to chemotherapy, radiation, targeted and immunotherapies are limited to a subset of patients making metastatic CRC (mCRC) difficult to treat. To understand the therapeutic modulation of immune response in mCRC, we have used a genetically engineered mouse model (GEMM), “KPN”, which resembles the human ‘CMS4’-like subtype. We show here that transforming growth factor (TGF-β1), secreted by KPN organoids, increases cancer cell proliferation, and inhibits splenocyte activation in vitro. TGF-β1 also inhibits activation of naive but not pre-activated T cells, suggesting differential effects on specific immune cells. In vivo, the inhibition of TGF-β inflames the KPN tumors, causing infiltration of T cells, monocytes and monocytic intermediates, while reducing neutrophils and epithelial cells. Co-inhibition of TGF-β and PD-L1 signaling further enhances cytotoxic CD8+T cells and upregulates innate immune response and interferon gene signatures. However, simultaneous upregulation of cancer-related metabolic genes correlated with limited control of tumor burden and/or progression despite combination treatment. Our study illustrates the importance of using GEMMs to predict better immunotherapies for mCRC.