Distinct T cell signatures are associated with Staphylococcus aureus skin infection in pediatric atopic dermatitis.

Atopic dermatitis (AD) is an inflammatory skin condition with a childhood prevalence of up to 25%. Microbial dysbiosis is characteristic of AD, with Staphylococcus aureus the most frequent pathogen associated with disease flares and increasingly implicated in disease pathogenesis. Therapeutics to mitigate the effects of S. aureus have had limited efficacy and S. aureus-associated temporal disease flares are synonymous with AD. An alternative approach is an anti-S. aureus vaccine, tailored to AD. Experimental vaccines have highlighted the importance of T cells in conferring protective anti-S. aureus responses; however, correlates of T cell immunity against S. aureus in AD have not been identified. We identify a systemic and cutaneous immunological signature associated with S. aureus skin infection (ADS.aureus) in a pediatric AD cohort, using a combined Bayesian multinomial analysis. ADS.aureus was most highly associated with elevated cutaneous chemokines IP10 and TARC, which preferentially direct Th1 and Th2 cells to skin. Systemic CD4+ and CD8+ T cells, except for Th2 cells, were suppressed in ADS.aureus, particularly circulating Th1, memory IL-10+ T cells, and skin-homing memory Th17 cells. Systemic γδ T cell expansion in ADS.aureus was also observed. This study suggests that augmentation of protective T cell subsets is a potential therapeutic strategy in the management of S. aureus in AD.

IP-10 and complement activation as friend or foe in COVID-19.

INTRODUCTION: The Innate immune system senses danger signals of COVID-19 infection and produce an orchestration of cellular, complement and cytokines cascades. These led to the approach using immunosuppressive agents. It is intriguing whether certain biomarkers can aid the proper administration of such drugs. METHODS: Plasma specimens of 58 COVID-19 patients with differing severity, from very mild illness (group A), mild (group B), moderate (group C), and severe/critical illness (group D) were assayed for cyto-chemokines and terminal complement complex (SC5b-9) during the course of diseases. None received anti-IL-6 therapy, there was no mortality in this cohort. RESULTS: IP-10 and RANTES levels were dominant cytokines. IP-10 levels increased significantly in all groups when compared between pre-nadir and nadir phases (group A, p =0.428; group B =0.034; group C =0.159; group D <0.001) and in groups B and D when compared between nadir and recovery phases (p <0.001). RANTES levels were elevated in all groups across all phases with no significant differences. SC5b-9 levels increased significantly as compared to healthy controls [pre-nadir- group A versus healthy, p =0.122; group B-D versus healthy, p =0.021); nadir-group A versus healthy, p =0.003; group B-D versus healthy, p <0.001; recovery phase (p <0.001)] but not between groups A and B-D at pre-nadir (p=0.606). CONCLUSION: The absence of significant pro-inflammatory responses and early elevation of IP-10 levels and complement activation may be favorable and necessary for viral elimination in COVID-19 patients. Expression of distinct cyto-chemokines during each clinical phase may be useful for guiding proper therapeutic interventions on alleviating thrombo-inflammation responses to COVID-19 infection.

Distinguishing Incubation and Acute Disease Stages of Mild-to-Moderate COVID-19.

While numerous studies have already compared the immune responses against SARS-CoV-2 in severely and mild-to-moderately ill COVID-19 patients, longitudinal trajectories are still scarce. We therefore set out to analyze serial blood samples from mild-to-moderately ill patients in order to define the immune landscapes for differently progressed disease stages. Twenty-two COVID-19 patients were subjected to consecutive venipuncture within seven days after diagnosis or admittance to hospital. Flow cytometry was performed to analyze peripheral blood immune cell compositions and their activation as were plasma levels of cytokines and SARS-CoV-2 specific immunoglobulins. Healthy donors served as controls. Integrating the kinetics of plasmablasts and SARS-CoV-2 specific antibodies allowed for the definition of three disease stages of early COVID-19. The incubation phase was characterized by a sharp increase in pro-inflammatory monocytes and terminally differentiated cytotoxic T cells. The latter correlated significantly with elevated concentrations of IP-10. Early acute infection featured a peak in PD-1+ cytotoxic T cells, plasmablasts and increasing titers of virus specific antibodies. During late acute infection, immature neutrophils were enriched, whereas all other parameters returned to baseline. Our findings will help to define landmarks that are indispensable for the refinement of new anti-viral and anti-inflammatory therapeutics, and may also inform clinicians to optimize treatment and prevent fatal outcomes.

GPR182 limits antitumor immunity via chemokine scavenging in mouse melanoma models.

For many solid tumors, immune checkpoint blockade therapy has become first line treatment, yet a large proportion of patients with immunologically cold tumors do not benefit due to the paucity of tumor infiltrating lymphocytes. Here we show that the orphan G Protein-Coupled Receptor 182 (GPR182) contributes to immunotherapy resistance in cancer via scavenging chemokines that are important for lymphocyte recruitment to tumors. GPR182 is primarily upregulated in melanoma-associated lymphatic endothelial cells (LECs) during tumorigenesis, and this atypical chemokine receptor endocytoses chemokines promiscuously. In GPR182-deficient mice, T cell infiltration into transplanted melanomas increases, leading to enhanced effector T cell function and improved antitumor immunity. Ablation of GPR182 leads to increased intratumoral concentrations of multiple chemokines and thereby sensitizes poorly immunogenic tumors to immune checkpoint blockade and adoptive cellular therapies. CXCR3 blockade reverses the improved antitumor immunity and T cell infiltration characteristic of GPR182-deficient mice. Our study thus identifies GPR182 as an upstream regulator of the CXCL9/CXCL10/CXCR3 axis that limits antitumor immunity and as a potential therapeutic target in immunologically cold tumors.

Overcoming resistance to immune checkpoint therapy in PTEN-null prostate cancer by intermittent anti-PI3Kα/ß/δ treatment.

Combining immune checkpoint therapy (ICT) and targeted therapy holds great promises for broad and long-lasting anti-cancer therapies. However, combining ICT with anti-PI3K inhibitors have been challenging because the multifaceted effects of PI3K on both cancer cells and immune cells within the tumor microenvironment. Here we find that intermittent but not daily dosing of a PI3Kα/ß/δ inhibitor, BAY1082439, on Pten-null prostate cancer models could overcome ICT resistance and unleash CD8+ T cell-dependent anti-tumor immunity in vivo. Mechanistically, BAY1082439 converts cancer cell-intrinsic immune-suppression to immune-stimulation by promoting IFNα/IFNγ pathway activation, ß2-microglubin expression and CXCL10/CCL5 secretion. With its preferential regulatory T cell inhibition activity, BAY1082439 promotes clonal expansion of tumor-associated CD8+ T cells, most likely via tertiary lymphoid structures. Once primed, tumors remain T cell-inflamed, become responsive to anti-PD-1 therapy and have durable therapeutic effect. Our data suggest that intermittent PI3K inhibition can alleviate Pten-null cancer cell-intrinsic immunosuppressive activity and turn "cold" tumors into T cell-inflamed ones, paving the way for successful ICT.

Immune response to cytosolic DNA via intercellular receptor modulation in oral keratinocytes and fibroblasts.

OBJECTIVE: Double-strand (ds) DNA-enveloped viruses can cause oral infection. Our aim is to investigate whether oral mucosal cells participate in immune response against cytosolic dsDNA invasion. METHODS: We examined the response to transfected herpes simplex virus (HSV) dsDNA via intracellular receptors in oral keratinocytes (RT7) and fibroblasts (GT1), and the effect of TNF-α on those responses. RESULTS: Transfected dsDNA increased CXCL10 expression via NF-κB activation in both cell types, while those responses were inhibited by knockdown of RIG-I, an RNA sensor. Although IFI16, a DNA sensor, was expressed in the nuclei of both types, its knockdown decreased transfected dsDNA-induced CXCL10 expression in GT1 but not RT7 cells. IFI16 in GT1 cells was translocated into cytoplasm from nuclei, which was attributed to immune response to cytosolic dsDNA. TNF-α enhanced transfected dsDNA-induced CXCL10, and knockdown of IFI16 decreased TNF-α and dsDNA-driven CXCL10 expression in both RT7 and GT1 cells. Finally, the combination of TNF-α and transfected dsDNA resulted in translocation of IFI16 from nuclei to cytoplasm in RT7 cells. CONCLUSION: RIG-I and IFI16 in oral mucosal cells may play important roles in host immune response against DNA viral infection, while TNF-α contributes to development of an antiviral system via those intracellular receptors.

Anatomically distinct fibroblast subsets determine skin autoimmune patterns.

The skin serves as a physical barrier and an immunological interface that protects the body from the external environment1-3. Aberrant activation of immune cells can induce common skin autoimmune diseases such as vitiligo, which are often characterized by bilateral symmetric lesions in certain anatomic regions of the body4-6. Understanding what orchestrates the activities of cutaneous immune cells at an organ level is necessary for the treatment of autoimmune diseases. Here we identify subsets of dermal fibroblasts that are responsible for driving patterned autoimmune activity, by using a robust mouse model of vitiligo that is based on the activation of endogenous auto-reactive CD8+ T cells that target epidermal melanocytes. Using a combination of single-cell analysis of skin samples from patients with vitiligo, cell-type-specific genetic knockouts and engraftment experiments, we find that among multiple interferon-γ (IFNγ)-responsive cell types in vitiligo-affected skin, dermal fibroblasts are uniquely required to recruit and activate CD8+ cytotoxic T cells through secreted chemokines. Anatomically distinct human dermal fibroblasts exhibit intrinsic differences in the expression of chemokines in response to IFNγ. In mouse models of vitiligo, regional IFNγ-resistant fibroblasts determine the autoimmune pattern of depigmentation in the skin. Our study identifies anatomically distinct fibroblasts with permissive or repressive IFNγ responses as the key determinant of body-level patterns of lesions in vitiligo, and highlights mesenchymal subpopulations as therapeutic targets for treating autoimmune diseases.

Immunological Microenvironment Alterations in Follicles of Patients With Autoimmune Thyroiditis.

Autoimmune thyroiditis (AIT) is the most prevalent autoimmune endocrine disease, with a higher incidence in women than in men. Immunological abnormalities may lead to the impairment of ovarian folliculogenesis; however, whether the presence of AIT affects immunological microenvironment in follicles remains controversial. We performed a cross-sectional study including 122 patients, aged 20-40 years, who underwent IVF/ICSI treatment owing to isolated male or tube factor infertility. Patients were divided into AIT and control groups according to clinical presentation, thyroid function, and thyroid autoantibody measurements. Follicular fluid was collected and the distribution of cytokines/chemokines in follicular fluid was measured by flow cytometry using multiplex bead assays between the two groups. Based on differences in levels of intrafollicular chemokines and cytokines between the AIT and control groups, the relevant inflammatory cascade was further demonstrated. Among the 12 chemokines analyzed, three (CXCL9, CXCL10, and CXCL11) showed significantly elevated levels in the follicular fluid of patients with AIT. Among the 11 cytokines detected, compared with those in the control group, significantly higher levels of IFNγ were observed in patients with AIT. IFNγ dose-dependently stimulated the expression and secretion of CXCL9/10/11 in cultured primary granulosa cells. The percentage of CXCR3+ T lymphocytes was significantly elevated in the follicular microenvironment of patients with AIT. We concluded that the IFNγ-CXCL9/10/11-CXCR3+ T lymphocyte inflammatory cascade is activated in the follicular microenvironment of patients with AIT. These findings indicate that a considerable immune imbalance occurred in the follicular microenvironment of patients with AIT.

Pathogenic Roles of CXCL10 in Experimental Autoimmune Prostatitis by Modulating Macrophage Chemotaxis and Cytokine Secretion.

Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) is an inflammatory immune disease characterized by intraprostatic leukocyte infiltration and pelvic or perineal pain. Macrophages play vital roles in the pathogenesis of CP/CPPS. However, the mechanisms controlling the activation and chemotaxis of macrophages in CP/CPPS remain unclear. This study aimed to investigate the roles of the CXCL10/CXCR3 pathway in the activation and chemotaxis of macrophages in CP/CPPS patients. The serums of CP/CPPS patients and healthy volunteers were collected and measured. Results showed that CXCL10 expression was significantly elevated and correlated with the severity of CP/CPPS patients. The experimental autoimmune prostatitis (EAP) model was generated, and adeno-associated virus and CXCR3 inhibitors were used to treat EAP mice. Immunofluorescence, flow cytometry, and Western blotting were used to analyze the functional phenotype and regulation mechanism of macrophages. Results showed that CXCL10 deficiency ameliorates EAP severity by inhibiting infiltration of macrophages to prostate. Moreover, CXCL10 could induce macrophage migrations and secretions of proinflammatory mediators via CXCR3, which consequently activated the downstream Erk1/2 and p38 MAPK signaling pathways. We also showed that prostatic stromal cell is a potential source of CXCL10. Our results indicated CXCL10 as an important mediator involved in inflammatory infiltration and pain symptoms of prostatitis by promoting the migration of macrophages and secretion of inflammatory mediators via CXCR3-mediated ERK and p38 MAPK activation.

Regulation of intestinal immunity and tissue repair by enteric glia.

Tissue maintenance and repair depend on the integrated activity of multiple cell types1. Whereas the contributions of epithelial2,3, immune4,5 and stromal cells6,7 in intestinal tissue integrity are well understood, the role of intrinsic neuroglia networks remains largely unknown. Here we uncover important roles of enteric glial cells (EGCs) in intestinal homeostasis, immunity and tissue repair. We demonstrate that infection of mice with Heligmosomoides polygyrus leads to enteric gliosis and the upregulation of an interferon gamma (IFNγ) gene signature. IFNγ-dependent gene modules were also induced in EGCs from patients with inflammatory bowel disease8. Single-cell transcriptomics analysis of the tunica muscularis showed that glia-specific abrogation of IFNγ signalling leads to tissue-wide activation of pro-inflammatory transcriptional programs. Furthermore, disruption of the IFNγ-EGC signalling axis enhanced the inflammatory and granulomatous response of the tunica muscularis to helminths. Mechanistically, we show that the upregulation of Cxcl10 is an early immediate response of EGCs to IFNγ signalling and provide evidence that this chemokine and the downstream amplification of IFNγ signalling in the tunica muscularis are required for a measured inflammatory response to helminths and resolution of the granulomatous pathology. Our study demonstrates that IFNγ signalling in enteric glia is central to intestinal homeostasis and reveals critical roles of the IFNγ-EGC-CXCL10 axis in immune response and tissue repair after infectious challenge.

Interleukin-30 feeds breast cancer stem cells via CXCL10 and IL23 autocrine loops and shapes immune contexture and host outcome.

BACKGROUND: Breast cancer (BC) progression to metastatic disease is the leading cause of death in women worldwide. Metastasis is driven by cancer stem cells (CSCs) and signals from their microenvironment. Interleukin (IL) 30 promotes BC progression, and its expression correlates with disease recurrence and mortality. Whether it acts by regulating BCSCs is unknown and could have significant therapeutic implications. METHODS: Human (h) and murine (m) BCSCs were tested for their production of and response to IL30 by using flow cytometry, confocal microscopy, proliferation and sphere-formation assays, and PCR array. Immunocompetent mice were used to investigate the role of BCSC-derived IL30 on tumor development and host outcome. TCGA PanCancer and Oncomine databases provided gene expression data from 1084 and 75 hBC samples, respectively, and immunostaining unveiled the BCSC microenvironment. RESULTS: hBCSCs constitutively expressed IL30 as a membrane-anchored glycoprotein. Blocking IL30 hindered their proliferation and self-renewal efficiency, which were boosted by IL30 overexpression. IL30 regulation of immunity gene expression in human and murine BCSCs shared a significant induction of IL23 and CXCL10. Both immunoregulatory mediators stimulated BCSC proliferation and self-renewal, while their selective blockade dramatically hindered IL30-dependent BCSC proliferation and mammosphere formation. Orthotopic implantation of IL30-overexpressing mBCSCs, in syngeneic mice, gave rise to poorly differentiated and highly proliferating MYC+KLF4+LAG3+ tumors, which expressed CXCL10 and IL23, and were infiltrated by myeloid-derived cells, Foxp3+ T regulatory cells and NKp46+RORγt+ type 3 innate lymphoid cells, resulting in increased metastasis and reduced survival. In tumor tissues from patients with BC, expression of IL30 overlapped with that of CXCL10 and IL23, and ranked beyond the 95th percentile in a Triple-Negative enriched BC collection from the Oncomine Platform. CIBERSORTx highlighted a defective dendritic cell, CD4+ T and γδ T lymphocyte content and a prominent LAG3 expression in IL30highversus IL30low human BC samples from the TCGA PanCancer collection. CONCLUSIONS: Constitutive expression of membrane-bound IL30 regulates BCSC viability by juxtacrine signals and via second-level mediators, mainly CXCL10 and IL23. Their autocrine loops mediate much of the CSC growth factor activity of IL30, while their paracrine effect contributes to IL30 shaping of immune contexture. IL30-related immune subversion, which also emerged from computational analyses, strongly suggests that targeting IL30 can restrain the BCSC compartment and counteract BC progression.

HCV Core Protein Induces Chemokine CCL2 and CXCL10 Expression Through NF-κB Signaling Pathway in Macrophages.

HCV core protein is the first structural protein synthesized during hepatitis C virus (HCV) infection and replication. It is released from virus infected liver cells and mediates multiple functions to affect host cell response. The innate immune response is the first line of defense against viral infection. After HCV infection, Kupffer cells (KCs) which are liver macrophages play an important role in host innate immune response. Kupffer cells act as phagocytes and release different cytokines and chemokines to counter viral infection and regulate inflammation and fibrosis in liver. Earlier, we have demonstrated that HCV core protein interacts with gC1qR and activates MAPK, NF-κB and PI3K/AKT pathways in macrophages. In this study, we explored the effect of HCV core protein on CCL2 and CXCL10 expression in macrophages and the signaling pathways involved. Upon silencing of gC1qR, we observed a significant decrease expression of CCL2 and CXCL10 in macrophages in the presence of HCV core protein. Inhibiting NF-κB pathway, but not P38, JNK, ERK and AKT pathways greatly reduced the expression of CCL2 and CXCL10. Therefore, our results indicate that interaction of HCV core protein with gC1qR could induce CCL2 and CXCL10 secretion in macrophages via NF-κB signaling pathway. These findings may shed light on the understanding of how leukocytes migrate into the liver and exaggerate host-derived immune responses and may provide novel therapeutic targets in HCV chronic inflammation.

Role of CXCL10 in the progression of in situ to invasive carcinoma of the breast.

Tumor immune microenvironment plays a crucial role in tumor progression. We performed immune profiling to compare immune-related gene expression between ductal carcinoma in situ (DCIS) and invasive carcinoma of the breast using nCounter PanCancer immune Profiling Panel and found that CXCL10 was the most significant gene that had the highest difference in expression between them. Effect of CXCL10 on breast cancer cell proliferation and invasion was examined in vitro, and expression of CXCL10 and its relationship with immune cell infiltration was assessed in breast cancer samples. CXCL10 induced cell proliferation, migration and epithelial-mesenchymal transition in MCF-7 and MDA-MB-231 breast cancer cell lines. We confirmed that CXCL10 mRNA expression was significantly higher in invasive carcinoma than in DCIS, especially in hormone receptor (HR)-negative tumors using a validation set. CXCL10 mRNA expression showed a positive correlation with tumor infiltrating lymphocyte (TIL) density in both DCIS and invasive carcinoma; CXCL10-positive tumors generally showed higher infiltration of CD8+ and FOXP3+TILs as well as PD-L1+ immune cells compared to CXCL10-negative tumors, albeit with different patterns according to HR status. In conclusion, our study showed that CXCL10 promotes tumor cell proliferation, invasion, and immune cell infiltration, implying its contribution in the progression of DCIS to invasive carcinoma of the breast.

Decellularised Human Umbilical Artery as a Vascular Graft Elicits Minimal Pro-Inflammatory Host Response Ex Vivo and In Vivo.

Small diameter (<6 mm) vessel grafts still pose a challenge for scientists worldwide. Decellularised umbilical artery (dUA) remains promising as small diameter tissue engineered vascular graft (TEVG), yet their immunogenicity remains unknown. Herein, we evaluated the host immune responses, with a focus on the innate part, towards human dUA implantation in mice, and confirmed our findings in an ex vivo allogeneic human setup. Overall, we did not observe any differences in the number of circulating white blood cells nor the number of monocytes among three groups of mice (1) dUA patch; (2) Sham; and (3) Mock throughout the study (day -7 to 28). Likewise, we found no difference in systemic inflammatory and anti-inflammatory cytokine levels between groups. However, a massive local remodelling response with M2 macrophages were observed in the dUA at day 28, whereas M1 macrophages were less frequent. Moreover, human monocytes from allogeneic individuals were differentiated into macrophages and exposed to lyophilised dUA to maximize an eventual M1 response. Yet, dUA did not elicit any immediate M1 response as determined by the absence of CCR7 and CXCL10. Together this suggests that human dUA elicits a minimal pro-inflammatory response further supporting its use as a TEVG in an allogeneic setup.

Potential Role of CXCL10 in Monitoring Response to Treatment in Leprosy Patients.

The treatment of multibacillary cases of leprosy with multidrug therapy (MDT) comprises 12 doses of a combination of rifampicin, dapsone and clofazimine. Previous studies have described the immunological phenotypic pattern in skin lesions in multibacillary patients. Here, we evaluated the effect of MDT on skin cell phenotype and on the Mycobacterium leprae-specific immune response. An analysis of skin cell phenotype demonstrated a significant decrease in MRS1 (SR-A), CXCL10 (IP-10) and IFNG (IFN-γ) gene and protein expression after MDT release. Patients were randomized according to whether they experienced a reduction in bacillary load after MDT. A reduction in CXCL10 (IP-10) in sera was associated with the absence of a reduction in the bacillary load at release. Although IFN-γ production in response to M. leprae was not affected by MDT, CXCL10 (IP-10) levels in response to M. leprae increased in cells from patients who experienced a reduction in bacillary load after treatment. Together, our results suggest that CXCL10 (IP-10) may be a good marker for monitoring treatment efficacy in multibacillary patients.

Systemic IL-15, IFN-γ, and IP-10/CXCL10 signature associated with effective immune response to SARS-CoV-2 in BNT162b2 mRNA vaccine recipients.

Early responses to vaccination are important for shaping both humoral and cellular protective immunity. Dissecting innate vaccine signatures may predict immunogenicity to help optimize the efficacy of mRNA and other vaccine strategies. Here, we characterize the cytokine and chemokine responses to the 1st and 2nd dose of the BNT162b2 mRNA (Pfizer/BioNtech) vaccine in antigen-naive and in previously coronavirus disease 2019 (COVID-19)-infected individuals (NCT04743388). Transient increases in interleukin-15 (IL-15) and interferon gamma (IFN-γ) levels early after boost correlate with Spike antibody levels, supporting their use as biomarkers of effective humoral immunity development in response to vaccination. We identify a systemic signature including increases in IL-15, IFN-γ, and IP-10/CXCL10 after the 1st vaccination, which were enriched by tumor necrosis factor alpha (TNF-α) and IL-6 after the 2nd vaccination. In previously COVID-19-infected individuals, a single vaccination results in both strong cytokine induction and antibody titers similar to the ones observed upon booster vaccination in antigen-naive individuals, a result with potential implication for future public health recommendations.

The Pro-Inflammatory Chemokines CXCL9, CXCL10 and CXCL11 Are Upregulated Following SARS-CoV-2 Infection in an AKT-Dependent Manner.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmissible RNA virus that is the causative agent of the Coronavirus disease 2019 (COVID-19) pandemic. Patients with severe COVID-19 may develop acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) and require mechanical ventilation. Key features of SARS-CoV-2 induced pulmonary complications include an overexpression of pro-inflammatory chemokines and cytokines that contribute to a 'cytokine storm.' In the current study an inflammatory state in Calu-3 human lung epithelial cells was characterized in which significantly elevated transcripts of the immunostimulatory chemokines CXCL9, CXCL10, and CXCL11 were present. Additionally, an increase in gene expression of the cytokines IL-6, TNFα, and IFN-γ was observed. The transcription of CXCL9, CXCL10, IL-6, and IFN-γ was also induced in the lungs of human transgenic angiotensin converting enzyme 2 (ACE2) mice infected with SARS-CoV-2. To elucidate cell signaling pathways responsible for chemokine upregulation in SARS-CoV-2 infected cells, small molecule inhibitors targeting key signaling kinases were used. The induction of CXCL9, CXCL10, and CXCL11 gene expression in response to SARS-CoV-2 infection was markedly reduced by treatment with the AKT inhibitor GSK690693. Samples from COVID-19 positive individuals also displayed marked increases in CXCL9, CXCL10, and CXCL11 transcripts as well as transcripts in the AKT pathway. The current study elucidates potential pathway specific targets for reducing the induction of chemokines that may be contributing to SARS-CoV-2 pathogenesis via hyperinflammation.

CD163L1+CXCL10+ Macrophages are Enriched Within Colonic Lamina Propria of Diverticulitis Patients.

BACKGROUND: Inflammation of diverticula, which are outpouchings of the colonic bowl wall, causes diverticulitis. Severe cases of diverticulitis require surgical intervention. Through RNA-seq analysis of intestinal tissues, we previously found that the innate immune response was deregulated in surgical diverticulitis patients. In that study, pro-inflammatory and macrophage markers were differentially expressed in the colons of diverticulitis versus control patients. Here we investigate CD163L1+ macrophages and the pro-inflammatory chemokine, CXCL10, in diverticulitis. MATERIALS AND METHODS: We assessed tissue from an uninvolved area adjacent to a region of the sigmoid colon chronically affected by diverticulitis and performed Spearman's correlation on transcripts associated with macrophage signaling. We identified altered CD163L1 and CXCL10 gene expression levels that we confirmed by RT-qPCR analysis on an independent cohort of diverticulitis patients and controls. We used immunofluorescence microscopy to localize CD163L1+ macrophages and CXCL10 levels in intestinal tissue and ELISA to measure CXCL10 levels in patient serum. RESULTS: We found a positive correlation between intestinal CD163L1 and CXCL10 gene expression and an increased number of CD163L1+ macrophages in the sigmoid colons of diverticulitis patients relative to controls (P = 0.036). Macrophages at the apices of colonic crypts expressed the chemokine CXCL10. Correspondingly, these diverticulitis patients also displayed heightened CXCL10 levels in their serum (P = 0.007). CONCLUSIONS: We identified a novel population of CD163L1+CXCL10+ macrophages in the colonic crypts of diverticulitis patients and demonstrated increased expression of serum CXCL10 in these patients. CXCL10 may serve as a prognostic biomarker to aid in clinical decision making for diverticulitis patients.

Anti-tumor immunity in mismatch repair-deficient colorectal cancers requires type I IFN-driven CCL5 and CXCL10.

Colorectal cancers (CRCs) deficient in DNA mismatch repair (dMMR) contain abundant CD8+ tumor-infiltrating lymphocytes (TILs) responding to the abundant neoantigens from their unstable genomes. Priming of such tumor-targeted TILs first requires recruitment of CD8+ T cells into the tumors, implying that this is an essential prerequisite of successful dMMR anti-tumor immunity. We have discovered that selective recruitment and activation of systemic CD8+ T cells into dMMR CRCs strictly depend on overexpression of CCL5 and CXCL10 due to endogenous activation of cGAS/STING and type I IFN signaling by damaged DNA. TIL infiltration into orthotopic dMMR CRCs is neoantigen-independent and followed by induction of a resident memory-like phenotype key to the anti-tumor response. CCL5 and CXCL10 could be up-regulated by common chemotherapies in all CRCs, indicating that facilitating CD8+ T cell recruitment underlies their efficacy. Induction of CCL5 and CXCL10 thus represents a tractable therapeutic strategy to induce TIL recruitment into CRCs, where local priming can be maximized even in neoantigen-poor CRCs.

CXCL10/CXCR3 signaling contributes to an inflammatory microenvironment and its blockade enhances progression of murine pancreatic precancerous lesions.

The development of pancreatic cancer requires recruitment and activation of different macrophage populations. However, little is known about how macrophages are attracted to the pancreas after injury or an oncogenic event, and how they crosstalk with lesion cells or other cells of the lesion microenvironment. Here, we delineate the importance of CXCL10/CXCR3 signaling during the early phase of murine pancreatic cancer. We show that CXCL10 is produced by pancreatic precancerous lesion cells in response to IFNγ signaling and that inflammatory macrophages are recipients for this chemokine. CXCL10/CXCR3 signaling in macrophages mediates their chemoattraction to the pancreas, enhances their proliferation, and maintains their inflammatory identity. Blocking of CXCL10/CXCR3 signaling in vivo shifts macrophage populations to a tumor-promoting (Ym1+, Fizz+, Arg1+) phenotype, increases fibrosis, and mediates progression of lesions, highlighting the importance of this pathway in PDA development. This is reversed when CXCL10 is overexpressed in PanIN cells.