The Role of CXCR3 and Its Chemokine Ligands in Skin Disease and Cancer

MAPK activated kinase 2 inhibition shifts the chemokine signature in arthritis synovial fluid mononuclear cells from CXCR3 to CXCR2

BACKGROUND

The development of novel treatment strategies of immune-mediated inflammatory arthritis (IMIA) is still a clinical unmet need. The mitogen-activated protein kinase (MAPK) pathway is activated by environmental stressors, growth factors and inflammatory cytokines. However, the inhibition of central MAPK proteins has so far had undesirable side effects. The MAPK-activated protein kinase 2 (MK2) is a downstream mediator in the MAPK signaling pathway.

OBJECTIVES

The objective of this study was to explore the effects of a small molecule inhibiting MK2 on synovial fluid mononuclear cells from patients with IMIA.

METHODS

Synovial fluid mononuclear cells (SFMCs) were obtained from a study population consisting of patients with active rheumatoid arthritis (RA), peripheral spondyloarthritis (SpA) or psoriatic arthritis (PsA) with at least one swollen joint (for obtaining synovial fluid) (n = 11). SFMCs were cultured for 48 h with and without the MK2 inhibitor CC0786512 at 1000 nM, 333 nM and 111 nMand cell free supernatants were harvested and frozen before they were analyzed by the Olink proseek multiplex interferon panel.

RESULTS

In SFMCs cultured for 48 h, the MK2 inhibitor decreased the production of chemokine (C-X-C motif) ligand 9 (CXCL9) (P < 0.001), CXCL10 (P < 0.01), hepatocyte growth factor (HGF) (P < 0.01), CXCL11 (P < 0.01), tumor necrosisfactor-like weak inducer of apoptosis (TWEAK) (P < 0.05), and interleukin 12B (IL-12B) (P < 0.05) and increased the production of CXCL5 (P < 0.0001), CXCL1 (P < 0.0001), CXCL6 (P < 0.001), transforming growthfactoralpha (TGFα) (P = 0.01), monocyte-chemotactic protein 3 (MCP-3) (P < 0.01), latency-associated peptide (LAP) TGFβ (P < 0.05) dose-dependently.

CONCLUSIONS

This study reveals the downstream effects of MK2 inhibition on the secretory profile of SFMCs. Specifically, C-X-C motif chemokine receptors 3 (CXCR3) chemokines were decreased and CXCR2 chemokines were increased. This shift in the chemokine milieu may be one of the mechanisms behind the anti-inflammatory effects of MK2 inhibitors.

Regulation of Tumor and Metastasis Initiation by Chemokine Receptors

Tumor-initiating cells (TICs) are a rare sub-population of cells within the bulk of a tumor that are major contributors to tumor initiation, metastasis, and chemoresistance. TICs have a stem-cell-like phenotype that is dictated by the expression of master regulator transcription factors, including OCT4, NANOG, and SOX2. These transcription factors are expressed via activation of multiple signaling pathways that drive cancer initiation and progression. Importantly, these same signaling pathways can be activated by select chemokine receptors. Chemokine receptors are increasingly being revealed as major drivers of the TIC phenotype, as their signaling can lead to activation of stemness-controlling transcription factors. Additionally, the cell surface expression of chemokine receptors provides a unique therapeutic target to disrupt signaling pathways that control the expression of master regulator transcription factors and the TIC phenotype. This review summarizes the master regulator transcription factors known to dictate the TIC phenotype, along with the complex signaling pathways that can mediate their expression and the chemokine receptors that are most upstream of this phenotype.

Intratumoral delivery of TransCon™ TLR7/8 Agonist promotes sustained anti-tumor activity and local immune cell activation while minimizing systemic cytokine induction

Background

Intratumoral (IT) delivery of toll-like receptor (TLR) agonists has shown encouraging anti-tumor benefit in preclinical and early clinical studies. However, IT delivery of TLR agonists may lead to rapid effusion from the tumor microenvironment (TME), potentially limiting the duration of local inflammation and increasing the risk of systemic adverse events.

Methods

To address these limitations, TransCon^™ TLR7/8 Agonist—an investigational sustained-release prodrug of resiquimod that uses a TransCon linker and hydrogel technology to achieve sustained and predictable IT release of resiquimod—was developed. TransCon TLR7/8 Agonist was characterized for resiquimod release in vitro and in vivo, in mice and rats, and was assessed for anti-tumor efficacy and pharmacodynamic activity in mice.

Results

Following a single IT dose, TransCon TLR7/8 Agonist mediated potent tumor growth inhibition which was associated with sustained resiquimod release over several weeks with minimal induction of systemic cytokines. TransCon TLR7/8 Agonist monotherapy promoted activation of antigen-presenting cells in the TME and tumor-draining lymph nodes, with evidence of activation and expansion of CD8⁺ T cells in the tumor-draining lymph node and TME. Combination of TransCon TLR7/8 Agonist with systemic immunotherapy further promoted anti-tumor activity in TransCon TLR7/8 Agonist-treated tumors. In a bilateral tumor setting, combination of TransCon TLR7/8 Agonist with systemic IL-2 potentiated tumor growth inhibition in both injected and non-injected tumors and conferred protection against tumor rechallenge following complete regressions.

Conclusions

Our findings show that a single dose of TransCon TLR7/8 Agonist can mediate sustained local release of resiquimod in the TME and promote potent anti-tumor effects as monotherapy and in combination with systemic immunotherapy, supporting TransCon TLR7/8 Agonist as a novel intratumoral TLR agonist for cancer therapy. A clinical trial to evaluate the safety and efficacy of TransCon TLR7/8 Agonist, as monotherapy and in combination with pembrolizumab, in cancer patients is currently ongoing (transcendIT-101; NCT04799054).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02708-6.

Design, Synthesis, and Pharmacological Evaluation of Benzimidazolo-thiazoles as Potent CXCR3 Antagonists with Therapeutic Potential in Autoimmune Diseases: Discovery of ACT-672125

The chemokine receptor CXCR3 allows the selective recruitment of innate and adaptive inflammatory immune cells into inflamed tissue. CXCR3 ligands are secreted after exposure to pro-inflammatory cytokines. Upon binding to CXCR3 ligands, CXCR3 expressing T-lymphocytes migrate toward sites of inflammation and can promote tissue damage. Therefore, antagonizing this receptor may provide clinical benefits for patients suffering from autoimmune diseases characterized by high concentrations of CXCR3 ligands. Herein, we report the second part of our CXCR3 discovery program where we explored the benzimidazolo-thiazole core scaffold. The optimization of potency and the mitigation of an hERG liability are described. Further pharmacokinetic considerations led to the identification of the potent CXCR3 antagonist ACT-672125 (29). The compound showed good physicochemical properties and safety profile. In a proof-of-mechanism model of lung inflammation, ACT-672125 inhibited the recruitment of CXCR3 expressing T cells into the inflamed lung in a dose-dependent manner.

FoxP3+ CD8 T-cells in acute HIV infection and following early antiretroviral therapy initiation

Objectives

Besides CD4 regulatory T-cells (Tregs), immunosuppressor FoxP3+ CD8 T-cells are emerging as an important subset of Tregs, which contribute to immune dysfunction and disease progression in HIV infection. However, FoxP3+ CD8 T-cell dynamics in acute HIV infection and following early antiretroviral therapy (ART) initiation remain understudied.

Methods

Subsets of FoxP3+ CD8 T-cells were characterized both prospectively and cross-sectionally in PBMCs from untreated acute (n=26) and chronic (n=10) HIV-infected individuals, early ART-treated in acute infection (n=10, median of ART initiation: 5.5 months post-infection), ART-treated in chronic infection (n=10), elite controllers (n=18), and HIV-uninfected controls (n=21).

Results

Acute and chronic infection were associated with increased total, effector memory, and terminally differentiated FoxP3+ CD8 T-cells, while early ART normalized only the frequencies of total FoxP3+ CD8 T-cells. We observed an increase in FoxP3+ CD8 T-cell immune activation (HLADR+/CD38+), senescence (CD57+/CD28-), and PD-1 expression during acute and chronic infection, which were not normalized by early ART. FoxP3+ CD8 T-cells in untreated participants expressed higher levels of immunosuppressive LAP(TGF-β1) and CD39 than uninfected controls, whereas early ART did not affect their expression. The expression of gut-homing markers CCR9 and Integrin-β7 by total FoxP3+ CD8 T-cells and CD39+ and LAP(TGF-β1)+ FoxP3+ CD8 T-cells increased in untreated individuals and remained higher than in uninfected controls despite early ART. Elite controllers share most of the FoxP3+ CD8 T-cell characteristics in uninfected individuals.

Conclusions

Although early ART normalized total FoxP3+ CD8 T-cells frequencies, it did not affect the persistent elevation of the gut-homing potential of CD39+ and LAP(TGF-β1)+ FoxP3+ CD8 T-cell, which may contribute to immune dysfunction.

Mechanisms of dermatologic toxicities to immune checkpoint inhibitor cancer therapies

The discovery of immune checkpoint inhibition (ICI) sparked a revolution in the era of targeted anticancer therapy. While monoclonal antibodies targeting the CTLA-4 and PD-1 axes have improved survival in patients with advanced cancers, these immunotherapies are associated with a wide spectrum of dermatologic immune-related adverse events (irAEs). Several publications have addressed the clinical and histopathologic classification of these skin-directed irAEs, their impact on antitumor immunity and survival, and the critical role of supportive oncologic dermatology in their management. Here, we review the current understanding of the mechanistic drivers of immune-related skin toxicities with a focus on inflammatory, immunobullous, melanocyte/pigment-related reactions. We detail the specific immune-based mechanisms that may underlie different cutaneous reactions. We also discuss potential mechanisms as they relate to non-cutaneous irAEs and potential overlap with cutaneous irAEs, techniques to study differences in immune-related versus de novo skin reactions, and how treatment of these adverse events impacts cancer treatment, patient quality of life, and overall survival. An improved understanding of the mechanistic basis of cutaneous irAEs will allow us to develop and utilize blood-based biomarkers that could help ultimately predict onset and/or severity of these irAEs and to implement rational mechanistic-based treatment strategies that are targeted to the irAEs while potentially avoiding abrogating anti-tumor effect of ICIs.

Gender-Diverse Inclusion in Immunological Research: Benefits to Science and Health

The differences between male and female immune systems are an under-researched field, ripe for discovery. This is evidenced by the stark sex biases seen in autoimmunity and infectious disease. Both the sex hormones (oestrogen and testosterone), as well as the sex chromosomes have been demonstrated to impact immune responses, in multiple ways. Historical shortcomings in reporting basic and clinical scientific findings in a sex-disaggregated manner have led not only to limited discovery of disease aetiology, but to potential inaccuracies in the estimation of the effects of diseases or interventions on females and gender-diverse groups. Here we propose not only that research subjects should include both cis-gender men and cis-gender women, but also transgender and gender-diverse people alongside them. The known interaction between the hormonal milieu and the sex chromosomes is inseparable in cis-gender human research, without the confounders of puberty and age. By inclusion of those pursuing hormonal affirmation of their gender identity- the individual and interactive investigation of hormones and chromosomes is permitted. Not only does this allow for a fine-tuned dissection of these individual effects, but it allows for discovery that is both pertinent and relevant to a far wider portion of the population. There is an unmet need for detailed treatment follow-up of the transgender community- little is known of the potential benefits and risks of hormonal supplementation on the immune system, nor indeed on many other health and disease outcomes. Our research team has pioneered the inclusion of gender-diverse persons in our basic research in adolescent autoimmune rheumatic diseases. We review here the many avenues that remain unexplored, and suggest ways in which other groups and teams can broaden their horizons and invest in a future for medicine that is both fruitful and inclusive.

Dampened Inflammatory Signalling and Myeloid-Derived Suppressor-Like Cell Accumulation Reduces Circulating Monocytic HLA-DR Density and May Associate With Malignancy Risk in Long-Term Renal Transplant Recipients

Background

Malignancy is a major cause of morbidity and mortality in transplant recipients. Identification of those at highest risk could facilitate pre-emptive intervention such as reduction of immunosuppression. Reduced circulating monocytic HLA-DR density is a marker of immune depression in the general population and associates with poorer outcome in critical illness. It has recently been used as a safety marker in adoptive cell therapy trials in renal transplantation. Despite its potential as a marker of dampened immune responses, factors that impact upon monocytic HLA-DR density and the long-term clinical sequelae of this have not been assessed in transplant recipients.

Methods

A cohort study of stable long-term renal transplant recipients was undertaken. Serial circulating monocytic HLA-DR density and other leucocyte populations were quantified by flow cytometry. Gene expression of monocytes was performed using the Nanostring nCounter platform, and 13-plex cytokine bead array used to quantify serum concentrations. The primary outcome was malignancy development during one-year follow-up. Risk of malignancy was calculated by univariate and multivariate proportionate hazards modelling with and without adjustment for competing risks.

Results

Monocytic HLA-DR density was stable in long-term renal transplant recipients (n=135) and similar to non-immunosuppressed controls (n=29), though was suppressed in recipients receiving prednisolone. Decreased mHLA-DRd was associated with accumulation of CD14+CD11b+CD33+HLA-DRlo monocytic myeloid-derived suppressor-like cells. Pathway analysis revealed downregulation of pathways relating to cytokine and chemokine signalling in monocytes with low HLA-DR density; however serum concentrations of major cytokines did not differ between these groups. There was an independent increase in malignancy risk during follow-up with decreased HLA-DR density.

Conclusions

Dampened chemokine and cytokine signalling drives a stable reduction in monocytic HLA-DR density in long-term transplant recipients and associates with subsequent malignancy risk. This may function as a novel marker of excess immunosuppression. Further study is needed to understand the mechanism behind this association.

Refractory alopecia universalis associated with dermatomyositis successfully treated with tofacitinib

Dermatomyositis (DM) and alopecia areata are two diseases characterised by aberrant interferon signalling. While patchy alopecia of the scalp is a known feature of DM, alopecia universalis, which involves hair loss over the entire body, has rarely been reported in conjunction with DM. Herein, we report the case of a 30-year-old female with DM who developed refractory cutaneous disease and alopecia universalis that were successfully treated with tofacitinib. This could suggest that concomitant severe alopecia and refractory cutaneous DM may reflect a strong baseline interferon gene signature that may predict responsiveness to janus kinase inhibitors.

Evolution, Expression and Functional Analysis of CXCR3 in Neuronal and Cardiovascular Diseases: A Narrative Review

Chemokines form a sophisticated communication network wherein they maneuver the spatiotemporal migration of immune cells across a system. These chemical messengers are recognized by chemokine receptors, which can trigger a cascade of reactions upon binding to its respective ligand. CXC chemokine receptor 3 (CXCR3) is a transmembrane G protein-coupled receptor, which can selectively bind to CXCL9, CXCL10, and CXCL11. CXCR3 is predominantly expressed on immune cells, including activated T lymphocytes and natural killer cells. It thus plays a crucial role in immunological processes like homing of effector cells to infection sites and for pathogen clearance. Additionally, it is expressed on several cell types of the central nervous system and cardiovascular system, due to which it has been implicated in several central nervous system disorders, including Alzheimer's disease, multiple sclerosis, dengue viral disease, and glioblastoma, as well as cardiovascular diseases like atherosclerosis, Chronic Chagas cardiomyopathy, and hypertension. This review provides a narrative description of the evolution, structure, function, and expression of CXCR3 and its corresponding ligands in mammals and zebrafish and the association of CXCR3 receptors with cardiovascular and neuronal disorders. Unraveling the mechanisms underlying the connection of CXCR3 and disease could help researchers investigate the potential of CXCR3 as a biomarker for early diagnosis and as a therapeutic target for pharmacological intervention, along with developing robust zebrafish disease models.

Amplification of the CXCR3/CXCL9 axis via intratumoral electroporation of plasmid CXCL9 synergizes with plasmid IL-12 therapy to elicit robust anti-tumor immunity

Clinical studies have demonstrated that local expression of the cytokine IL-12 drives interferon-gamma expression and recruits T cells to the tumor microenvironment, ultimately yielding durable systemic T cell responses. Interrogation of longitudinal biomarker data from our late-stage melanoma trials identified a significant on-treatment increase of intratumoral CXCR3 transcripts that was restricted to responding patients, underscoring the clinical relevance of tumor-infiltrating CXCR3⁺ immune cells. In this study, we sought to understand if the addition of DNA-encodable CXCL9 could augment the anti-tumor immune responses driven by intratumoral IL-12. We show that localized IL-12 and CXCL9 treatment reshapes the tumor microenvironment to promote dendritic cell licensing and CD8⁺ T cell activation. Additionally, this combination treatment results in a significant abscopal anti-tumor response and provides a concomitant benefit to anti-PD-1 therapies. Collectively, these data demonstrate that a functional tumoral CXCR3/CXCL9 axis is critical for IL-12 anti-tumor efficacy. Furthermore, restoring or amplifying the CXCL9 gradient in the tumors via intratumoral electroporation of plasmid CXCL9 can not only result in efficient trafficking of cytotoxic CD8⁺ T cells into the tumor but can also reshape the microenvironment to promote systemic immune response.

Lower CXCR3 expression in both patients with neovascular AMD and advanced stages of chronic myeloproliferative blood cancers

Purpose

Peripheral T cell CXCR3 expression has been found uniquely lower in patients having neovascular age-related macular degeneration (nAMD) than in healthy individuals. The CXCR3-axis has been shown to have angiostatic and antifibrotic properties. We have recently investigated systemic markers in patients with myeloproliferative neoplasms (MPNs) because of their higher prevalence of AMD, and we have observed higher systemic chronic low-grade inflammation and immunosenescence signs in MPNs with drusen (MPNd) compared to those with normal retinas (MPNn). The MPNs evolve in a biological continuum from early cancer-stages (essential thrombocytosis, polycythemia vera) to the advanced myelofibrosis stage. Especially myelofibrosis is characterized by bone marrow angiogenesis and fibrosis, similarly to retinal observations in nAMD. We speculate if we can find lower CXCR3 expression in MPNs, particularly myelofibrosis and if differences are seen between MPNd and MPNn. We also wanted to compare expression in nAMD and intermediate (i)AMD.

Methods

Patients in this cross-sectional study were 29 nAMD, 28 iAMD, 35 MPNd, and 27 MPNn. We performed flowcytometry on blood to measure CXCR3 expression.

Results

CD8+CXCR3 expression in nAMD was 6,1%, significantly lower than in iAMD 16%, MPNd 11%, MPNn 12% (p-values<0.05). Similar results were seen for CD4+CXCR3 expression. We also found CXCR3 expression decreasing over the MPN-continuum. For instance, in myelofibrosis, intermediate monocytes expression was 6.2%, significantly lower than 18% in ET and 18% in PV (p-values<0.05).

Conclusions

We find CXCR3 downregulation on T-cells and some monocyte subset in nAMD compared to iAMD, MPNd, and MPNn, in line with previous nAMD studies. We also find CXCR3 downregulation in most monocyte subsets over the MPN continuum. Systemic leukocyte CXCR3 expression could both be involved in changes seen in the retina and the bone marrow. Further understanding the CXCR3-axis in AMD and MPNs may elucidate underlying pathogenic mechanisms and reveal new targets for treatment.

Restoring Pro-healing/remodeling- associated M2a/c Macrophages using ON101 Accelerates Diabetic Wound Healing

Diabetic wounds exhibit chronic inflammation and delayed tissue proliferation or remodeling, mainly owing to prolonged proinflammatory (M1) macrophage activity and defects in transition to prohealing/proremodeling (M2a/M2c; CD206⁺ and/or CD163⁺) macrophages. We found that topical treatment with ON101, a plant-based potential therapeutic for diabetic foot ulcers, increased M2c-like (CD163⁺ and CD206⁺) cells and suppressed M1-like cells, altering the inflammatory gene profile in a diabetic mouse model compared with that in the controls. An in vitro macrophage-polarizing model revealed that ON101 directly suppressed CD80⁺ and CD86⁺ M1-macrophage polarization and M1-associated proinflammatory cytokines at both protein and transcriptional levels. Notably, conditioned medium collected from ON101-treated M1 macrophages reversed the M1-conditioned medium‒mediated suppression of CD206⁺ macrophages. Furthermore, conditioned medium from ON101-treated adipocyte progenitor cells significantly promoted CD206⁺ and CD163⁺ macrophages but strongly inhibited M1-like cells. ON101 treatment also stimulated the expression of GCSF and CXCL3 genes in human adipocyte progenitor cells. Interestingly, treatment with recombinant GCSF protein enhanced both CD206⁺ and CD163⁺ M2 markers, whereas CXCL3 treatment only stimulated CD163⁺ M2 macrophages. Depletion of cutaneous M2 macrophages inhibited ON101-induced diabetic wound healing. Thus, ON101 directly suppressed M1 macrophages and facilitated the GCSF- and CXCL3-mediated transition from M1 to M2 macrophages, lowering inflammation and leading to faster diabetic wound healing.

Precursors to Systemic Sclerosis and Systemic Lupus Erythematosus: From Undifferentiated Connective Tissue Disease to the Development of Identifiable Connective Tissue Diseases

The pathogenesis of connective tissue diseases (CTDs), such as systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), is characterized by derangements of the innate and adaptive immune system, and inflammatory pathways leading to autoimmunity, chronic cytokine production, and chronic inflammation. The diagnosis of these diseases is based on meeting established criteria with symptoms, signs and autoantibodies. However, there are pre-clinical states where criteria are not fulfilled but biochemical and autoimmune derangements are present. Understanding the underlying processes responsible for disease pathogenesis in pre-clinical states, which place patients at increased risk for the development of established connective tissue diseases, represents an opportunity for early identification and potentially enables timely treatment with the goal of limiting disease progression and improved prognosis. This scoping review describes the role of the innate and adaptive immune responses in the pre-clinical states of undifferentiated CTD at risk for SSc and prescleroderma, the evolution of antibodies from nonspecific to specific antinuclear antibodies prior to SLE development, and the signaling pathways and inflammatory markers of fibroblast, endothelial, and T cell activation underlying immune dysregulation in these pre-clinical states.

The Evasion Mechanisms of Cancer Immunity and Drug Intervention in the Tumor Microenvironment

Recently, in the field of cancer treatment, the paradigm has changed to immunotherapy that activates the immune system to induce cancer attacks. Among them, immune checkpoint inhibitors (ICI) are attracting attention as excellent and continuous clinical results. However, it shows not only limitations such as efficacy only in some patients or some indications, but also side-effects and resistance occur. Therefore, it is necessary to understand the factors of the tumor microenvironment (TME) that affect the efficacy of immunotherapy, that is, the mechanism by which cancer grows while evading or suppressing attacks from the immune system within the TME. Tumors can evade attacks from the immune system through various mechanisms such as restricting antigen recognition, inhibiting the immune system, and inducing T cell exhaustion. In addition, tumors inhibit or evade the immune system by accumulating specific metabolites and signal factors within the TME or limiting the nutrients available to immune cells. In order to overcome the limitations of immunotherapy and develop effective cancer treatments and therapeutic strategies, an approach is needed to understand the functions of cancer and immune cells in an integrated manner based on the TME. In this review, we will examine the effects of the TME on cancer cells and immune cells, especially how cancer cells evade the immune system, and examine anti-cancer strategies based on TME.

Initial TK-deficient HSV-1 infection in the lip alters contralateral lip challenge immune dynamics

Primary infection with herpes simplex type 1 (HSV-1) occurring around the mouth and nose switches rapidly to lifelong latent infection in sensitive trigeminal ganglia (TG) neurons. Sporadic reactivation of these latent reservoirs later in life is the cause of acute infections of the corneal epithelium, which can cause potentially blinding herpes simplex keratitis (HSK). There is no effective vaccine to protect against HSK, and antiviral drugs provide only partial protection against recurrences. We previously engendered an acute disease-free, non-reactivating latent state in mice when challenged with virulent HSV-1 in orofacial mucosa, by priming with non-neurovirulent HSV-1 (TK_del) before the challenge. Herein, we define the local immune infiltration and inflammatory chemokine production changes after virulent HSV-1 challenge, which were elicited by TK_del prime. Heightened immunosurveillance before virulent challenge, and early enhanced lymphocyte-enriched infiltration of the challenged lip were induced, which corresponded to attenuation of inflammation in the TG and enhanced viral control. Furthermore, classical latent-phase T cell persistence around latent HSV-1 reservoirs were severely reduced. These findings identify the immune processes that are likely to be responsible for establishing non-reactivating latent HSV-1 reservoirs. Stopping reactivation is essential for development of efficient vaccine strategies against HSV-1.

Activin-A impairs CD8 T cell-mediated immunity and immune checkpoint therapy response in melanoma

Background

Activin-A, a transforming growth factor β family member, is secreted by many cancer types and is often associated with poor disease prognosis. Previous studies have shown that Activin-A expression can promote cancer progression and reduce the intratumoral frequency of cytotoxic T cells. However, the underlying mechanisms and the significance of Activin-A expression for cancer therapies are unclear.

Methods

We analyzed the expression of the Activin-A encoding gene INHBA in melanoma patients and the influence of its gain- or loss-of-function on the immune infiltration and growth of BRAF-driven YUMM3.3 and iBIP2 mouse melanoma grafts and in B16 models. Using antibody depletion strategies, we investigated the dependence of Activin-A tumor-promoting effect on different immune cells. Immune-regulatory effects of Activin-A were further characterized in vitro and by an adoptive transfer of T cells. Finally, we assessed INHBA expression in melanoma patients who received immune checkpoint therapy and tested whether it impairs the response in preclinical models.

Results

We show that Activin-A secretion by melanoma cells inhibits adaptive antitumor immunity irrespective of BRAF status by inhibiting CD8⁺ T cell infiltration indirectly and even independently of CD4 T cells, at least in part by attenuating the production of CXCL9/10 by myeloid cells. In addition, we show that Activin-A/INHBA expression correlates with anti-PD1 therapy resistance in melanoma patients and impairs the response to dual anti-cytotoxic T-Lymphocyte associated protein 4/anti-PD1 treatment in preclinical models.

Conclusions

Our findings suggest that strategies interfering with Activin-A induced immune-regulation offer new therapeutic opportunities to overcome CD8 T cell exclusion and immunotherapy resistance.

Chronic Inflammation in Non-Healing Skin Wounds and Promising Natural Bioactive Compounds Treatment

Chronic inflammation is one of the hallmarks of chronic wounds and is tightly coupled to immune regulation. The dysregulation of the immune system leads to continuing inflammation and impaired wound healing and, subsequently, to chronic skin wounds. In this review, we discuss the role of the immune system, the involvement of inflammatory mediators and reactive oxygen species, the complication of bacterial infections in chronic wound healing, and the still-underexplored potential of natural bioactive compounds in wound treatment. We focus on natural compounds with antioxidant, anti-inflammatory, and antibacterial activities and their mechanisms of action, as well as on recent wound treatments and therapeutic advancements capitalizing on nanotechnology or new biomaterial platforms.

Vitiligo-specific soluble biomarkers as early indicators of response to immune checkpoint inhibitors in metastatic melanoma patients

Immunotherapy with checkpoint inhibitors (CPIs) strongly improved the outcome of metastatic melanoma patients. However, not all the patients respond to treatment and identification of prognostic biomarkers able to select responding patients is currently of outmost importance. Considering that development of vitiligo-like depigmentation in melanoma patients represents both an adverse event of CPIs and a favorable prognostic factor, we analyzed soluble biomarkers of vitiligo to validate them as early indicators of response to CPIs. Fifty-seven metastatic melanoma patients receiving CPIs were enrolled and divided according to the best overall response to treatment. Patient sera were evaluated at pre-treatment and after 1 and 3 months of therapy. We found that basal CD25 serum levels were higher in stable and responding patients and remained higher during the first 3 months of CPI therapy compared to non-responders. CXCL9 was absent in non-responding patients before therapy beginning. Moreover, an increase of CXCL9 levels was observed at 1 and 3 months of therapy for all patients, although higher CXCL9 amounts were present in stable and responding compared to non-responding patients. Variations in circulating immune cell subsets was also analyzed, revealing a reduced number of regulatory T lymphocytes in responding patients. Altogether, our data indicate that a pre-existing and maintained activation of the immune system could be an indication of response to CPI treatment in melanoma patients.

What Is Currently Known about the Role of CXCL10 in SARS-CoV-2 Infection?

Dysregulation of the immune response plays an important role in the progression of SARS-CoV-2 infection. A "cytokine storm", which is a phenomenon associated with uncontrolled production of large amounts of cytokines, very often affects patients with COVID-19. Elevated activity of chemotactic cytokines, called chemokines, can lead to serious consequences. CXCL10 has an ability to activate its receptor CXCR3, predominantly expressed on macrophages, T lymphocytes, dendritic cells, natural killer cells, and B cells. So, it has been suggested that the chemokine CXCL10, through CXCR3, is associated with inflammatory diseases and may be involved in the development of COVID-19. Therefore, in this review paper, we focus on the role of CXCL10 overactivity in the pathogenesis of COVID-19. We performed an extensive literature search for our investigation using the MEDLINE/PubMed database. Increased concentrations of CXCL10 were observed in COVID-19. Elevated levels of CXCL10 were reported to be associated with a severe course and disease progression. Published studies revealed that CXCL10 may be a very good predictive biomarker of patient outcome in COVID-19, and that markedly elevated CXCL10 levels are connected with ARDS and neurological complications. It has been observed that an effective treatment for SARS-CoV-2 leads to inhibition of "cytokine storm", as well as reduction of CXCL10 concentrations. It seems that modulation of the CXCL10-CXCR3 axis may be an effective therapeutic target of COVID-19. This review describes the potential role of CXCL10 in the pathogenesis of COVID-19, as well as its potential immune-therapeutic significance. However, future studies should aim to confirm the prognostic, clinical, and therapeutic role of CXCL10 in SARS-CoV-2 infection.

Gene Expression Profile Analyses of the Skin Response of Balb/c-Nu Mice Model Injected by Staphylococcus aureus

Background

Pathogenesis and persistence of many skin diseases are related to Staphylococcus aureus (S. aureus) colonization. S. aureus infection can cause varying degrees of changes in cell gene expression, resulting in complex changes in cell phenotype and finally changes in cell life activities.

Materials and Methods

The transcriptomes of healthy and Staphylococcus aureus (S. aureus)-infected murine skin tissues were analyzed. We identified 638 differentially expressed genes (DEGs) in the infected tissues compared to the control samples, of which 324 were upregulated and 314 were downregulated, following the criteria of P < 0.01 and |log₂FC| > 3. The DEGs were functionally annotated by Gene Ontology (GO), KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway and the protein–protein interaction (PPI) network analyses.

Results

The upregulated DEGs were mainly enriched in GO terms, such as response to stimulus, immune system process and signal transduction, as well as in the complement and coagulation cascade pathway. Thus, S. aureus infection likely activates these pathways to limit the influx of neutrophils and prevent skin damage. Four clusters were identified in the PPI network, and the major hubs were mainly related to cell cycle and proliferation, and mostly downregulated. The expression levels of Nox4, Mmrn1, Mcm5, Msx1 and Fgf5 mRNAs were validated by qRT-PCR and found to be consistent with the RNA-Seq data, confirming a strong correlation between the two approaches.

Conclusion

The identified genes and pathways are potential drug targets for treating skin inflammation caused by S. aureus and should be investigated further.

Identify potential prognostic indicators and tumor-infiltrating immune cells in pancreatic adenocarcinoma

Background: Pancreatic adenocarcinoma (PAAD) is a kind of highly malignant tumor and lacks early diagnosis method and effective treatment. Tumor microenvironment (TME) is of great importance for the occurrence and development of PAAD. Thus, a comprehensive overview of genes and tumor-infiltrating immune cells (TICs) related to TME dynamic changes conduce to develop novel therapeutic targets and prognostic indicators.

Methods: We used MAlignant Tumors using Expression data (ESTIMATE) algorithm to analyze the transcriptome RNA-seq data of 182 PAAD cases on The Cancer Genome Atlas (TCGA) platform. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), protein–protein interaction (PPI) network, COX regression analysis and gene set enrichment analysis (GSEA) were carried out to get the hub genes related to the prognosis of PAAD patients. These core genes were validated in GEPIA. CXCL10 expression as a poor prognostic indicator was validated in GEO database. Finally, CIBERSORT algorithm was applied to understand the status of TICs.

Results: A total of 715 up-regulated differential expression genes (DEGs) and 57 down-regulated DEGs were found simultaneously in stromal and immune groups. These DEGs were mainly enriched in immune recognition, activation and response processes. CD4, CXCL12, CXCL10, CCL5 and CXCL9 were the top five core genes. Then, the validation of these genes showed that CD4, CXCL10, CXCL5, CXCL9 were up-regulated in PAAD. Among the core genes, CXCL10 had a negative correlation with the survival time of PAAD patients. CD8+ T cells, CD4+ T cells memory activated, macrophages M1 had positive correlation of CXCL10 expression, whereas regulatory T cells (Tregs), macrophages M0 and B cells memory had negative correlation.

Conclusion: We generated a series of genes related to TME with prognostic implications and TICs in PAAD, which have the potential to be novel immunotherapy targets and prognostic markers. The data showed that CXCL10 was favorable as a poor prognostic indicator in PAAD patients.

Immunoprofiling Identifies Functional B and T Cell Subsets Induced by an Attenuated Whole Parasite Malaria Vaccine as Correlates of Sterile Immunity

Immune correlates of protection remain elusive for most vaccines. An identified immune correlate would accelerate the down-selection of vaccine formulations by reducing the need for human pathogen challenge studies that are currently required to determine vaccine efficacy. Immunization via mosquito-delivered, radiation-attenuated P. falciparum sporozoites (IMRAS) is a well-established model for efficacious malaria vaccines, inducing greater than 90% sterile immunity. The current immunoprofiling study utilized samples from a clinical trial in which vaccine dosing was adjusted to achieve only 50% protection, thus enabling a comparison between protective and non-protective immune signatures. In-depth immunoprofiling was conducted by assessing a wide range of antigen-specific serological and cellular parameters and applying our newly developed computational tools, including machine learning. The computational component of the study pinpointed previously un-identified cellular T cell subsets (namely, TNFα-secreting CD8⁺CXCR3⁻CCR6⁻ T cells, IFNγ-secreting CD8⁺CCR6⁺ T cells and TNFα/FNγ-secreting CD4⁺CXCR3⁻CCR6⁻ T cells) and B cell subsets (i.e., CD19⁺CD24^hiCD38^hiCD69⁺ transitional B cells) as important factors predictive of protection (92% accuracy). Our study emphasizes the need for in-depth immunoprofiling and subsequent data integration with computational tools to identify immune correlates of protection. The described process of computational data analysis is applicable to other disease and vaccine models.

Role of CXCL10 in Spinal Cord Injury

Spinal cord injury (SCI) results in acute inflammatory responses and secondary damages, including neuronal and glial cell death, axonal damage and demyelination, and blood-brain barrier (BBB) damage, eventually leading to neuronal dysfunction and other complications. C-X-C motif Chemokine Ligand 10 (CXCL10) is expressed after the injury, playing multiple roles in the development and progression of SCI. Moreover, the CXCL10 antagonist can restrict inflammatory immune responses and promote neuronal regeneration and functional recovery. In this review, we summarize the structure and biological functions of CXCL10, and the roles of the CXCL10 / CXCR3 axis in acute inflammatory responses, secondary damages, and complications during SCI, thus providing a potential theoretical basis by highlighting CXCL10 as a new potential drug target for the treatment of SCI.

Delayed antiretroviral therapy in HIV-infected individuals leads to irreversible depletion of skin- and mucosa-resident memory T cells

People living with HIV (PLWH) are at increased risk for developing skin and mucosal malignancies despite systemic reconstitution of CD4+ T cells upon antiretroviral therapy (ART). The underlying mechanism of chronic tissue-related immunodeficiency in HIV is unclear. We found that skin CD4+ tissue-resident memory T (Trm) cells were depleted after HIV infection and replenished only upon early ART initiation. TCR clonal analysis following early ART suggested a systemic origin for reconstituting CD4+ Trm cells. Single-cell RNA sequencing in PLWH that received late ART treatment revealed a loss of CXCR3+ Trm cells and a tolerogenic skin immune environment. Human papilloma virus-induced precancerous lesion biopsies showed reduced CXCR3+ Trm cell frequencies in the mucosa in PLWH versus HIV- individuals. These results reveal an irreversible loss of CXCR3+ Trm cells confined to skin and mucosa in PLWH who received late ART treatment, which may be a precipitating factor in the development of HPV-related cancer.

The Role of Tumor Microenvironment in Mycosis Fungoides and Sézary Syndrome

Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common subtypes of cutaneous T-cell lymphomas (CTCLs). Most cases of MF display an indolent course during its early stage. However, in some patients, it can progress to the tumor stage with potential systematic involvement and a poor prognosis. SS is defined as an erythrodermic CTCL with leukemic involvements. The pathogenesis of MF and SS is still not fully understood, but recent data have found that the development of MF and SS is related to genetic alterations and possibly to environmental influences. In CTCL, many components interacting with tumor cells, such as tumor-associated macrophages, fibroblasts, dendritic cells, mast cells, and myeloid-derived suppressor cells, as well as with chemokines, cytokines and other key players, establish the tumor microenvironment (TME). In turn, the TME regulates tumor cell migration and proliferation directly and indirectly and may play a critical role in the progression of MF and SS. The TME of MF and SS appear to show features of a Th2 phenotype, thus dampening tumor-related immune responses. Recently, several studies have been published on the immunological characteristics of MF and SS, but a full understanding of the CTCL-related TME remains to be determined. This review focuses on the role of the TME in MF and SS, aiming to further demonstrate the pathogenesis of the disease and to provide new ideas for potential treatments targeted at the microenvironment components of the tumor.

Oxidized carbon black nanoparticles induce endothelial damage through C-X-C chemokine receptor 3-mediated pathway

Oxidation of engineered nanomaterials during application in various industrial sectors can alter their toxicity. Oxidized nanomaterials also have widespread industrial and biomedical applications. In this study, we evaluated the cardiopulmonary hazard posed by these nanomaterials using oxidized carbon black (CB) nanoparticles (CBox) as a model particle. Particle surface chemistry was characterized by X-ray photo electron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR). Colloidal characterization and in vitro dosimetry modeling (particle kinetics, fate and transport modeling) were performed. Lung inflammation was assessed following oropharyngeal aspiration of CB or oxidized CBox particles (20 μg per mouse) in C57BL/6J mice. Toxicity and functional assays were also performed on murine macrophage (RAW 264.7) and endothelial cell lines (C166) with and without pharmacological inhibitors. Oxidant generation was assessed by electron paramagnetic resonance spectroscopy (EPR) and via flow cytometry. Endothelial toxicity was evaluated by quantifying pro-inflammatory mRNA expression, monolayer permeability, and wound closure. XPS and FTIR spectra indicated surface modifications, the appearance of new functionalities, and greater oxidative potential (both acellular and in vitro) of CBox particles. Treatment with CBox demonstrated greater in vivo inflammatory potentials (lavage neutrophil counts, secreted cytokine, and lung tissue mRNA expression) and air-blood barrier disruption (lavage proteins). Oxidant-dependent pro-inflammatory signaling in macrophages led to the production of CXCR3 ligands (CXCL9,10,11). Conditioned medium from CBox-treated macrophages induced significant elevation in endothelial cell pro-inflammatory mRNA expression, enhanced monolayer permeability and impairment of scratch healing in CXCR3 dependent manner. In summary, this study mechanistically demonstrated an increased biological potency of CBox particles and established the role of macrophage-released chemical mediators in endothelial damage.

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 IL30^highversus IL30^low 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.

Serum CXCL10/IP-10 may be a potential biomarker for severe Mycoplasma pneumoniae pneumonia in children

Background

How to early distinguish the severity of Mycoplasma pneumoniae pneumonia (MPP) is a worldwide concern in clinical practice. We therefore conducted this study to assess the relationship between levels of serum inflammatory chemokines and the severity of MPP.

Methods

In this prospective study, we enrolled 39 children with MPP, whose clinical information was collected, blood samples were assayed for cytokines and chemokines by ELISA.

Results

The levels of serum CXCL10 in children with severe MPP were significantly higher than those in children with mild MPP (2500.0 [1580.9–2500.0] vs. 675.7 [394.7–1134.9], P < 0.001). Measurement of CXCL10 levels in serum enabled the differentiation of children with severe MPP with an area under the curve (AUC) of 0.885 (95 % CI 0.779–0.991, P < 0.001), with a sensitivity of 81.0 % and a specificity of 83.3 %.

Conclusions

Serum CXCL10 level may be a potential biomarker for severe MPP in children.

Air pollution from traffic during pregnancy impairs newborn's cord blood immune cells: The NELA cohort

BACKGROUND

Hazards of traffic-related air pollution (TRAP) on the developing immune system are poorly understood. We sought to investigate the effects of prenatal exposure to TRAP on cord blood immune cell distributions; and to identify gestational windows of susceptibility.

METHODS

In-depth immunophenotyping of cord blood leukocyte and lymphocyte subsets was performed by flow cytometry in 190 newborns embedded in the Nutrition in Early Life and Asthma (NELA) birth cohort (2015-2018). Long-term (whole pregnancy and trimesters) and short-term (15-days before delivery) residential exposures to traffic-related nitrogen dioxide (NO₂), particulate matter (PM_2.5 and PM₁₀), and ozone (O₃) were estimated using dispersion/chemical transport modelling. Associations between TRAP concentrations and cord blood immune cell counts were assessed using multivariate Poisson regression models.

RESULTS

Mean number of natural killer (NK) cells decreased 15% in relation to higher NO₂ concentrations (≥36.4 μg/m3) during whole pregnancy (incidence relative risk (IRR), 0.85; 95% CI, 0.72, 0.99), with stronger associations in the first trimester. Higher PM_2.5 concentrations (≥13.3 μg/m³) during whole pregnancy associated with a reduced mean number of cytotoxic T cells (IRR, 0.88; 95% CI, 0.78, 0.99). Newborns exposed to higher PM₁₀ (≥23.6 μg/m³) and PM_2.5 concentrations during the first and third trimester showed greater mean number of helper T type 1 (Th1) cells (P < 0.05). Decreased number of regulatory T (Treg) cells was associated with greater short-term NO₂ (IRR, 0.90; 95% CI, 0.80, 1.01) and PM₁₀ (IRR, 0.88; 95% CI, 0.77, 0.99) concentrations.

CONCLUSIONS

Prenatal exposure to TRAP, particularly in early and late gestation, impairs fetal immune system development through disturbances in cord blood leukocyte and lymphocyte distributions.

Potential neurotoxic activity of diverse molecules released by microglia

Microglia are the professional immune cells of the brain, which support numerous physiological processes. One of the defensive functions provided by microglia involves secretion of cytotoxins aimed at destroying invading pathogens. It is also recognized that the adverse activation of microglia in diseased brains may lead to secretion of cytotoxic molecules, which could be damaging to the surrounding cells, including neurons. Several of these toxins, such as reactive oxygen and nitrogen species, L-glutamate, and quinolinic acid, are widely recognized and well-studied. This review is focused on a structurally diverse group of less-established microglia neurotoxins, which were selected by applying the two criteria that these molecules 1) can be released by microglia, and 2) have the potential to be directly harmful to neurons. The following 11 molecules are discussed in detail: amyloid beta peptides (Aβ); cathepsin (Cat)B and CatD; C-X-C motif chemokine ligand (CXCL)10 and CXCL12 (5-67); high mobility group box (HMGB)1; lymphotoxin (LT)-α; matrix metalloproteinase (MMP)-2 and MMP-9; platelet-activating factor (PAF); and prolyl endopeptidase (PEP). Molecular mechanisms of their release by microglia and neurotoxicity, as well as available evidence implicating their involvement in human neuropathologies are summarized. Further studies on several of the above molecules are warranted to confirm either their microglial origin in the brain or direct neurotoxic effects. In addition, investigations into the differential secretion patterns of neurotoxins by microglia in response to diverse stimuli are required. This research could identify novel therapeutic targets for neurological disorders involving adverse microglial activation.

Enrichment of CCR6+ CD8+ T cells and CCL20 in the lungs of mechanically ventilated patients with COVID-19

Despite high levels of CXCR3 ligands in mechanically ventilated COVID-19 patients, BALF CD8 T cells were not enriched in CXCR3+ cells but rather CCR6+ , likely due to high CCL20 levels in BALF, and had very high PD-1 expression. In mechanically ventilated, but not ward, patients Th-1 immunity is impaired. ​.

Rubella vaccine-induced granulomas are a novel phenotype with incomplete penetrance of genetic defects in cytotoxicity

BACKGROUND

Rubella virus-induced granulomas have been described in patients with various inborn errors of immunity. Most defects impair T-cell immunity, suggesting a critical role of T cells in rubella elimination. However, the molecular mechanism of virus control remains elusive.

OBJECTIVE

This study sought to understand the defective effector mechanism allowing rubella vaccine virus persistence in granulomas.

METHODS

Starting from an index case with Griscelli syndrome type 2 and rubella skin granulomas, this study combined an international survey with a literature search to identify patients with cytotoxicity defects and granuloma. The investigators performed rubella virus immunohistochemistry and PCR and T-cell migration assays.

RESULTS

This study identified 21 patients with various genetically confirmed cytotoxicity defects, who presented with skin and visceral granulomas. Rubella virus was demonstrated in all 12 accessible biopsies. Granuloma onset was typically before 2 years of age and lesions persisted from months to years. Granulomas were particularly frequent in MUNC13-4 and RAB27A deficiency, where 50% of patients at risk were affected. Although these proteins have also been implicated in lymphocyte migration, 3-dimensional migration assays revealed no evidence of impaired migration of patient T cells. Notably, patients showed no evidence of reduced control of concomitantly given measles, mumps, or varicella live-attenuated vaccine or severe infections with other viruses.

CONCLUSIONS

This study identified lymphocyte cytotoxicity as a key effector mechanism for control of rubella vaccine virus, without evidence for its need in control of live measles, mumps, or varicella vaccines. Rubella vaccine-induced granulomas are a novel phenotype with incomplete penetrance of genetic disorders of cytotoxicity.

Persistent Herpes Simplex Virus Type 1 Infection of Enteric Neurons Triggers CD8+ T Cell Response and Gastrointestinal Neuromuscular Dysfunction

Behind the central nervous system, neurotropic viruses can reach and persist even in the enteric nervous system (ENS), the neuronal network embedded in the gut wall. We recently reported that immediately following orogastric (OG) administration, Herpes simplex virus (HSV)-1 infects murine enteric neurons and recruits mononuclear cells in the myenteric plexus. In the current work, we took those findings a step forward by investigating the persistence of HSV-1 in the ENS and the local adaptive immune responses against HSV-1 that might contribute to neuronal damage in an animal model. Our study demonstrated specific viral RNA transcripts and proteins in the longitudinal muscle layer containing the myenteric plexus (LMMP) up to 10 weeks post HSV-1 infection. CD3⁺CD8⁺INFγ⁺ lymphocytes skewed towards HSV-1 antigens infiltrated the myenteric ganglia starting from the 6^th week of infection and persist up to 10 weeks post-OG HSV-1 inoculation. CD3⁺CD8⁺ cells isolated from the LMMP of the infected mice recognized HSV-1 antigens expressed by infected enteric neurons. In vivo, infiltrating activated lymphocytes were involved in controlling viral replication and intestinal neuromuscular dysfunction. Indeed, by depleting the CD8⁺ cells by administering specific monoclonal antibody we observed a partial amelioration of intestinal dysmotility in HSV-1 infected mice but increased expression of viral genes. Our findings demonstrate that HSV-1 persistently infects enteric neurons that in turn express viral antigens, leading them to recruit activated CD3⁺CD8⁺ lymphocytes. The T-cell responses toward HSV-1 antigens persistently expressed in enteric neurons can alter the integrity of the ENS predisposing to neuromuscular dysfunction.

Human CD8 T-stem cell memory subsets phenotypic and functional characterization are defined by expression of CD122 or CXCR3

Long-lived T-memory stem cells (T_SCM ) are key to both naturally occurring and vaccine-conferred protection against infection. These cells are characterized by the CD45RA⁺ CCR7⁺ CD95⁺ phenotype. Significant heterogeneity within the T_SCM population is recognized, but distinguishing surface markers and functional characterization of potential subsets are lacking. Human CD8 T_SCM subsets were identified in healthy subjects who had been previously exposed to CMV or Influenza (Flu) virus in flow cytometry by expression of CD122 or CXCR3, and then characterized in proliferation, multipotency, self-renewal, and intracellular cytokine production (TNF-α, IL-2, IFN-γ), together with transcriptomic profiles. The T_SCM CD122^hi -expressing subset (versus CD122^lo ) demonstrated greater proliferation, greater multipotency, and enhanced polyfunctionality with higher frequencies of triple positive (TNF-α, IL-2, IFN-γ) cytokine-producing cells upon exposure to recall antigen. The T_SCM CXCR3^lo subpopulation also had increased proliferation and polyfunctional cytokine production. Transcriptomic analysis further showed that the T_SCM CD122^hi population had increased expression of activation and homing molecules, such as Ccr6, Cxcr6, Il12rb, and Il18rap, and downregulated cell proliferation inhibitors, S100A8 and S100A9. These data reveal that the T_SCM CD122^hi phenotype is associated with increased proliferation, enhanced multipotency and polyfunctionality with an activated memory-cell like transcriptional profile, and hence, may be favored for induction by immunization and for adoptive immunotherapy.

Potential predictive biomarkers of adalimumab response in patients with hidradenitis suppurativa

BACKGROUND

Adalimumab provides significant efficacy for patients with hidradenitis suppurativa (HS), which was demonstrated by at least 50% of patients achieving a clinical response by week 12 that was maintained through to week 168 in the PIONEER trials.

OBJECTIVES

To identify whether there are biomarkers that could predict adalimumab response, as well as markers that differentially respond to adalimumab in patients with HS.

METHODS

Baseline and week-12 plasma samples from the PIONEER studies were used to assess the levels of circulating proteins by multiplex and enzyme-linked immunosorbent assays.

RESULTS

Analyses revealed significantly higher high-sensitivity C-reactive protein (hs-CRP) and chemokine (C-C motif) ligand (CCL) 16 (HCC-4) levels in nonresponders at baseline and identified a multivariate response signature of calprotectin, fractalkine and HCC-4, reaching an 86% predictive accuracy rate for adalimumab response. Additionally, post-treatment reduction of plasma C-X-C motif chemokine ligand (CXCL)9, CXCL8 (interleukin-8) and CCL19 (macrophage inflammatory protein 3β) were greater in adalimumab super-responders than in nonresponders (P = 0·026, P = 0·044 and P = 0·026, respectively). These cytokines are involved in the recruitment of innate and adaptive inflammatory cells, and/or stimulation of certain inflammatory responses, suggesting that these pathways could be disease drivers in adalimumab nonresponders.

CONCLUSIONS

These initial results suggest HCC-4, calprotectin and fractalkine could be potential predictive biomarkers of adalimumab response in HS and identified possible tumour necrosis factor-independent disease pathways.

Investigating T Cell Immunity in Cancer: Achievements and Prospects

T cells play a key role in tumour surveillance, both identifying and eliminating transformed cells. However, as tumours become established they form their own suppressive microenvironments capable of shutting down T cell function, and allowing tumours to persist and grow. To further understand the tumour microenvironment, including the interplay between different immune cells and their role in anti-tumour immune responses, a number of studies from mouse models to clinical trials have been performed. In this review, we examine mechanisms utilized by tumour cells to reduce their visibility to CD8⁺ Cytotoxic T lymphocytes (CTL), as well as therapeutic strategies trialled to overcome these tumour-evasion mechanisms. Next, we summarize recent advances in approaches to enhance CAR T cell activity and persistence over the past 10 years, including bispecific CAR T cell design and early evidence of efficacy. Lastly, we examine mechanisms of T cell infiltration and tumour regression, and discuss the strengths and weaknesses of different strategies to investigate T cell function in murine tumour models.

CXCL9-expressing tumor-associated macrophages: new players in the fight against cancer

Tumor-associated macrophages (TAMs) are among the main contributors to immune suppression in the tumor microenvironment, however, TAM depletion strategies have yielded little clinical benefit. Here, we discuss the concept that TAMs are also key regulators of anti-PD(L)-1-mediated CD8 T cell-dependent immunity. Emerging data suggest that expression of the chemokine CXCL9 by TAMs regulates the recruitment and positioning of CXCR3-expressing stem-like CD8 T (T_stem) cells that underlie clinical responses to anti-PD(L)-1 treatment. We evaluate clinical and mechanistic studies that establish relationships between CXCL9-expressing TAMs, T_stem and antitumor immunity. Therapies that enhance anti-PD(L)-1 response rates must consider TAM CXCL9 expression. In this perspective, we discuss opportunities to enhance the frequency and function of CXCL9 expressing TAMs and draw on comparative analyzes from infectious disease models to highlight potential functions of these cells beyond T_stem recruitment.

Differential combination immunotherapy requirements for inflamed (warm) tumors versus T cell excluded (cool) tumors: engage, expand, enable, and evolve

Background

Different types of tumors have varying susceptibility to immunotherapy and hence require different treatment strategies; these cover a spectrum ranging from ‘hot’ tumors or those with high mutational burden and immune infiltrates that are more amenable to targeting to ‘cold’ tumors that are more difficult to treat due to the fewer targetable mutations and checkpoint markers. We hypothesized that an effective anti-tumor response requires multiple agents that would (1) engage the immune response and generate tumor-specific effector cells; (2) expand the number and breadth of the immune effector cells; (3) enable the anti-tumor activity of these immune cells in the tumor microenvironment; and (4) evolve the tumor response to widen immune effector repertoire.

Methods

A hexatherapy combination was designed and administered to MC38-CEA (warm) and 4T1 (cool) murine tumor models. The hexatherapy regimen was composed of adenovirus-based vaccine and IL-15 (interleukin-15) superagonist (N-803) to engage the immune response; anti-OX40 and anti-4-1BB to expand effector cells; anti-PD-L1 (anti-programmed death-ligand 1) to enable anti-tumor activity; and docetaxel to promote antigen spread. Primary and metastatic tumor growth inhibition were measured. The generation of anti-tumor immune effector cells was analyzed using flow cytometry, ELISpot (enzyme-linked immunospot), and RNA analysis.

Results

The MC38-CEA and 4T1 tumor models have differential sensitivities to the combination treatments. In the ‘warm’ MC38-CEA, combinations with two to five agents resulted in moderate therapeutic benefit while the hexatherapy regimen outperformed all these combinations. On the other hand, the hexatherapy regimen was required in order to decrease the primary and metastatic tumor burden in the ‘cool’ 4T1 model. In both models, the hexatherapy regimen promoted CD4⁺ and CD8⁺ T cell proliferation and activity. Furthermore, the hexatherapy regimen induced vaccine-specific T cells and stimulated antigen cascade. The hexatherapy regimen also limited the immunosuppressive T cell and myeloid derived suppressor cell populations, and also decreased the expression of exhaustion markers in T cells in the 4T1 model.

Conclusion

The hexatherapy regimen is a strategic combination of immuno-oncology agents that can engage, expand, enable, and evolve the immune response and can provide therapeutic benefits in both MC38-CEA (warm) and 4T1 (cool) tumor models.

Induction of CXCL10-Mediated Cell Migration by Different Types of Galectins

Chemokines are an extended group of chemoattractant cytokines responsible for the recruitment of leukocytes into tissues. Among them, interferon-γ-inducible protein 10 (CXCL10) is abundantly expressed following inflammatory stimuli and participates in the trafficking of monocytes and activated T cells into sites of injury. Here, we report that different members of the galectin family of carbohydrate-binding proteins promote the expression and synthesis of CXCL10 independently of interferon-γ. Interestingly, CXCL10 induction was observed when galectins came in contact with stromal fibroblasts isolated from human cornea but not other cell types such as epithelial, monocytic or endothelial cells. Induction of CXCL10 by the tandem repeat galectin-8 was primarily associated with the chemotactic migration of THP-1 monocytic cells, whereas the prototype galectin-1 promoted the CXCL10-dependent migration of Jurkat T cells. These results highlight the potential importance of the galectin signature in dictating the recruitment of specific leukocyte populations into precise tissue locations.

Identification of novel candidate genes in rosacea by bioinformatic methods

BACKGROUND

Rosacea is a chronic inflammatory skin disease whose psychological consequences severely affect patient's quality of life.

OBJECTIVE

To identify candidate genes of rosacea for potential development of new target therapies.

METHODS

Gene Expression Omnibus datasets were retrieved to obtain differentially expressed genes (DEGs) between rosacea patients and healthy controls. Gene ontology (GO) analyses were used to identify functions of candidate genes. Related signaling pathways of DEGs were analyzed using Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene set enrichment analysis. Protein-protein interaction (PPI) networks were applied using search tools for the retrieval of interacting genes/proteins and modulations involving PPI networks were evaluated with use of the MCODE app.

RESULTS

Samples from 19 rosacea patients and 10 healthy controls of dataset GSE65914 were enrolled. A total of 215 DEGs, 115 GO terms and 6 KEGG pathways were identified. A total of 182 nodes and 456 edges were enriched in PPI networks. Maximal clusters showed 15 central nodes and 96 edges. The toll-like receptor (TLR) signaling pathway was the most significant pathway detected and 5 DEGs were identified as candidate genes which included TLR2, C-C motif chemokine (CCL) 5, C-X-C motif chemokine ligand (CXCL) 9, CXCL10 and CXCL11. The results were verified in rosacea patients with use of real-time polymerase chain reaction and immunohistochemistry. Cell-type enrichment analysis revealed 8 lymphocytes that were enriched in rosacea patients.

CONCLUSIONS

The results suggest that both innate and adaptive immune responses were involved in the etiology of rosacea. Five DEGs in the TLR signaling pathway may serve as potential therapeutic target genes.

Development of an Immune-Related Gene Signature for Prognosis in Melanoma

Melanoma remains a potentially deadly malignant tumor. The incidence of melanoma continues to rise. Immunotherapy has become a new treatment method and is widely used in a variety of tumors. Original melanoma data were downloaded from TCGA. ssGSEA was performed to classify them. GSVA software and the "hclust" package were used to analyze the data. The ESTIMATE algorithm screened DEGs. The edgeR package and Venn diagram identified valid immune-related genes. Univariate, LASSO and multivariate analyses were used to explore the hub genes. The "rms" package established the nomogram and calibrated the curve. Immune infiltration data were obtained from the TIMER database. Compared with that of samples in the high immune cell infiltration cluster, we found that the tumor purity of samples in the low immune cell infiltration cluster was higher. The immune score, ESTIMATE score and stromal score in the low immune cell infiltration cluster were lower. In the high immune cell infiltration cluster, the immune components were more abundant, while the tumor purity was lower. The expression levels of TIGIT, PDCD1, LAG3, HAVCR2, CTLA4 and the HLA family were also higher in the high immune cell infiltration cluster. Survival analysis showed that patients in the high immune cell infiltration cluster had shorter OS than patients in the low immune cell infiltration cluster. IGHV1-18, CXCL11, LTF, and HLA-DQB1 were identified as immune cell infiltration-related DEGs. The prognosis of melanoma was significantly negatively correlated with the infiltration of CD4+ T cells, CD8+ T cells, dendritic cells, neutrophils and macrophages. In this study, we identified immune-related melanoma core genes and relevant immune cell subtypes, which may be used in targeted therapy and immunotherapy of melanoma.

C3a and Its Receptor C3aR Are Detectable in Normal Human Epidermal Keratinocytes and Are Differentially Regulated via TLR3 and LL37

To study the molecular interplay between TLRs and complement representing ancient danger-sensing mechanisms, we examined the regulation of the C3a/anaphylatoxin C3a receptor (C3aR) axis in normal human epidermal keratinocytes (NHEKs) by treatment with different TLR ligands. Protein staining followed by flow cytometry revealed highly constitutive intracellular expression levels of the C3aR in NHEKs. Stimulation with Poly I:C up-regulated C3aR mRNA and intra- and extracellular expression in NHEKs which showed functional relevance by up-regulating CXCL10 and down-regulating C3 expression in response to C3a. mRNA and protein levels of C3 and protease cathepsin L (CTSL) that can cleave C3 were up-regulated by the TLR3 ligand Poly I:C. Enhanced intracellular expression levels of the biologically active C3 fragment (C3a), in response to TLR3 stimulation were also detectable in NHEKs. Cathelicidin antimicrobial peptide LL-37 potentiated Poly I:C-induced C3aR, C3, and CTSL up-regulation. In conclusion, we point to a role of TLR3 to promote up-regulation of C3aR, C3, and CTSL expression levels and generation of C3a. Our data provide evidence that local generation and activation of complement components as described for T cells or myeloid cells represent a scenario which may take place in a similar way in NHEKs.

Regulatory T Cells in the Tumor Microenvironment

Regulatory T cells (T_regs) are an immunosuppressive subpopulation of CD4⁺ T cells that are endowed with potent suppressive activity and function to limit immune activation and maintain homeostasis. These cells are identified by the hallmark transcription factor FOXP3 and the high-affinity interleukin-2 (IL-2) receptor chain CD25. T_regs can be recruited to and persist within the tumor microenvironment (TME), acting as a potent barrier to effective antitumor immunity. This chapter will discuss [i] the history and hallmarks of T_regs; [ii] the recruitment, development, and persistence of T_regs within the TME; [iii] T_reg function within TME; asnd [iv] the therapeutic targeting of T_regs in the clinic. This chapter will conclude with a discussion of likely trends and future directions.

Tumor-infiltrating mast cells are associated with resistance to anti-PD-1 therapy

Anti-PD-1 therapy is used as a front-line treatment for many cancers, but mechanistic insight into this therapy resistance is still lacking. Here we generate a humanized (Hu)-mouse melanoma model by injecting fetal liver-derived CD34⁺ cells and implanting autologous thymus in immune-deficient NOD-scid IL2Rγ^null (NSG) mice. Reconstituted Hu-mice are challenged with HLA-matched melanomas and treated with anti-PD-1, which results in restricted tumor growth but not complete regression. Tumor RNA-seq, multiplexed imaging and immunohistology staining show high expression of chemokines, as well as recruitment of FOXP3⁺ Treg and mast cells, in selective tumor regions. Reduced HLA-class I expression and CD8⁺/Granz B⁺ T cells homeostasis are observed in tumor regions where FOXP3⁺ Treg and mast cells co-localize, with such features associated with resistance to anti-PD-1 treatment. Combining anti-PD-1 with sunitinib or imatinib results in the depletion of mast cells and complete regression of tumors. Our results thus implicate mast cell depletion for improving the efficacy of anti-PD-1 therapy.

Immune checkpoint therapies (ICT) are promising for treating various cancers, but response rates vary. Here the authors show, in mouse models, that tumor-infiltrating mast cells colocalize with regulatory T cells, coincide with local reduction of MHC-I and CD8 T cells, and is associated with resistance to ICT, which can be reversed by c-kit inhibitor treatment.

ILB® resolves inflammatory scarring and promotes functional tissue repair

Fibrotic disease is a major cause of mortality worldwide, with fibrosis arising from prolonged inflammation and aberrant extracellular matrix dynamics. Compromised cellular and tissue repair processes following injury, infection, metabolic dysfunction, autoimmune conditions and vascular diseases leave tissues susceptible to unresolved inflammation, fibrogenesis, loss of function and scarring. There has been limited clinical success with therapies for inflammatory and fibrotic diseases such that there remains a large unmet therapeutic need to restore normal tissue homoeostasis without detrimental side effects. We investigated the effects of a newly formulated low molecular weight dextran sulfate (LMW-DS), termed ILB^®, to resolve inflammation and activate matrix remodelling in rodent and human disease models. We demonstrated modulation of the expression of multiple pro-inflammatory cytokines and chemokines in vitro together with scar resolution and improved matrix remodelling in vivo. Of particular relevance, we demonstrated that ILB^® acts, in part, by downregulating transforming growth factor (TGF)β signalling genes and by altering gene expression relating to extracellular matrix dynamics, leading to tissue remodelling, reduced fibrosis and functional tissue regeneration. These observations indicate the potential of ILB^® to alleviate fibrotic diseases.

Tumor inhibition or tumor promotion? The duplicity of CXCR3 in cancer

Tumor tissue includes cancer cells and normal stromal cells such as vascular endothelial cells, connective tissue cells (cancer associated fibroblast, mesenchymal stem cell), and immune cells (tumor-infiltrating lymphocytes or TIL, dendritic cells, eosinophils, basophils, mast cells, tumor-associated macrophages or TAM, myeloid-derived suppressor cells or MDSC). Anti-tumor activity is mainly mediated by infiltration of NK cells, Th1 and CD8⁺ T cells, and correlates with expression of NK cell and T cell attracting chemokines. Nevertheless, cancer cells hijack tissue homeostasis through secretion of cytokines and chemokines that mediate not only the induction of an inflamed status that supports cancer cell survival and growth, but also the recruitment and/or activation of immune suppressive cells. CXCL9, CXCL10, and CXCL11 are known for their tumor-inhibiting properties, but their overexpression in several hematologic and solid tumors correlates with disease severity, suggesting a role in tumor promotion. The dichotomous nature of CXCR3 ligands activity mainly depends on several molecular mechanisms induced by cancer cells themselves able to divert immune responses and to alter the whole local environment. A deep understanding of the nature of such phenomenon may provide a rationale to build up a CXCR3/ligand axis targeting strategy. In this review, we will discuss the role of CXCR3 in cancer progression and in regulation of anti-tumor immune response and immunotherapy.

Clinical and molecular insights into BCG immunotherapy for melanoma

The incidence of cutaneous melanoma and the mortality rate of advanced melanoma patients continue to rise globally. Despite the recent success of immunotherapy including ipilimumab and pembrolizumab checkpoint inhibitors, a large proportion of patients are refractory to such treatment modalities. The application of mycobacteria such as Bacillus Calmette-Guérin (BCG) in the treatment of various malignancies, including cutaneous melanoma, has been clearly demonstrated after almost a century of observations and experimentation. Intralesional BCG (IL-BCG) immunotherapy is a highly efficient and cost-effective treatment option for inoperable stage III in-transit melanoma, as recommended in the National Comprehensive Cancer Network Guidelines. IL-BCG has shown great efficacy in the regression of directly injected metastatic melanoma lesions, as well as distal noninjected nodules in immunocompetent patients. Clinical and preclinical studies have shown that BCG serves as a strong immune modulator, inducing the recruitment of various immune cells that contribute to antitumour immunity. However, the specific mechanism of BCG-mediated tumour immunity remains poorly understood. Comparative genome analyses have revealed that different BCG strains exhibit distinct immunological activity and virulence, which might impact the therapeutic response and clinical outcome of patients. In this review, we discuss the immunostimulatory potential of different BCG substrains and highlight clinical studies utilizing BCG immunotherapy for the treatment of cutaneous melanoma. Furthermore, the review focuses on the cellular and molecular mechanisms of the BCG-induced immune responses of both the innate and adaptive arms of the immune system. Furthermore, the review discussed the administration of BCG as a monotherapy or in combination with other immunotherapeutic or chemotherapeutic agents.

Biased agonism at chemokine receptors

In the human chemokine system, interactions between the approximately 50 known endogenous chemokine ligands and 20 known chemokine receptors (CKRs) regulate a wide range of cellular functions and biological processes including immune cell activation and homeostasis, development, angiogenesis, and neuromodulation. CKRs are a family of G protein-coupled receptors (GPCR), which represent the most common and versatile class of receptors in the human genome and the targets of approximately one third of all Food and Drug Administration-approved drugs. Chemokines and CKRs bind with significant promiscuity, as most CKRs can be activated by multiple chemokines and most chemokines can activate multiple CKRs. While these ligand-receptor interactions were previously regarded as redundant, it is now appreciated that many chemokine:CKR interactions display biased agonism, the phenomenon in which different ligands binding to the same receptor signal through different pathways with different efficacies, leading to distinct biological effects. Notably, these biased responses can be modulated through changes in ligand, receptor, and or the specific cellular context (system). In this review, we explore the biochemical mechanisms, functional consequences, and therapeutic potential of biased agonism in the chemokine system. An enhanced understanding of biased agonism in the chemokine system may prove transformative in the understanding of the mechanisms and consequences of biased signaling across all GPCR subtypes and aid in the development of biased pharmaceuticals with increased therapeutic efficacy and safer side effect profiles.