Chemokines in homeostasis and diseases

Bilayer lipids modulate ligand binding to atypical chemokine receptor 3

Chemokine receptors belong to the large class of G protein-coupled receptors (GPCRs) and are involved in a number of (patho)physiological processes. Previous studies highlighted the importance of membrane lipids for modulating GPCR structure and function. However, the underlying mechanisms of how lipids regulate GPCRs are often poorly understood. Here, we report that anionic lipid bilayers increase the binding affinity of the chemokine CXCL12 for the atypical chemokine receptor 3 (ACKR3) by modulating the CXCL12 binding kinetics. Notably, the anionic bilayer favors CXCL12 over the more positively charged chemokine CXCL11, which we explained by bilayer interactions orienting CXCL12 but not CXCL11 for productive ACKR3 binding. Furthermore, our data suggest a stabilization of active ACKR3 conformations in anionic bilayers. Taken together, the described regulation of chemokine selectivity of ACKR3 by the lipid bilayer proposes an extended version of the classical model of chemokine binding including the lipid environment of the receptor.

Ca2+ transients on the T cell surface trigger rapid integrin activation in a timescale of seconds

One question in lymphocyte homing is how integrins are rapidly activated to enable immediate arrest of fast rolling lymphocytes upon encountering chemokines at target vascular beds given the slow chemokine-induced integrin inside-out activation. Herein we demonstrate that chemokine CCL25-triggered Ca2+ influx induces T cell membrane-proximal external Ca2+ concentration ([Ca2+]ex) drop in 6 s from physiological concentration 1.2 mM to 0.3 mM, a critical extracellular Ca2+ threshold for inducing αLβ2 activation, triggering rapid αLβ2 activation and T cell arrest before occurrence of αLβ2 inside-out activation. Talin knockdown inhibits the slow inside-out activation of αLβ2 but not [Ca2+]ex drop-triggered αLβ2 quick activation. Blocking Ca2+ influx significantly suppresses T cell rolling-to-arrest transition and homing to skin lesions in a mouse psoriasis model, thus alleviating skin inflammation. [Ca2+]ex decrease-triggered rapid integrin activation bridges the gap between initial chemokine stimulation and slow integrin inside-out activation, ensuring immediate lymphocyte arrest and subsequent diapedesis on the right location.

CCL16 is a pro-tumor chemokine that recruits monocytes and macrophages to promote hepatocellular carcinoma progression

Intricate signaling cascades involving chemokines and their cognate receptors on neoplastic and immune constituents within tumor microenvironment have garnered substantial research interest. Our investigation delineates the contribution of Chemokine (C-C motif) ligand 16 (CCL16) to the clinico-pathological features and tumorigenesis of hepatocellular carcinoma (HCC). Analysis of 237 pairs of HCC specimens unraveled a significant association between CCL16 expression and vascular invasion, early-stage clinicopathological features, and diminished recurrence-free survival among HCC patients. Immunohistochemical (IHC) assays of the clinical HCC specimens indicated elevated CCL16 in tumorous versus normal hepatic tissues. Our in vivo experiments demonstrated CCL16 overexpression fostered tumor proliferation, whereas in vitro assays elucidated that CCL16-mediated chemotactic recruitment of monocytes and M2 macrophages was orchestrated via CCR1 and CCR5. In contrast to previous claims that CCL16 is physiologically irrelevant and has minimal affinity for its receptors (CCR1, CCR2, CCR5, CCR8), our findings unravel that inhibition of CCL16/CCR1 and CCL16/CCR5 interactions through receptor-specific antagonists markedly impeded CCL16-directed chemotaxis, migration, adhesion, and leukocyte recruitment. Moreover, CCL16-overexpression in HCCs significantly augmented levels of several cytokines implicated in tumor progression, namely IL-6, IL-10 and VEGFA. IHC analysis of CCL16-overexpressing xenografts elicited greatly enhanced levels of VEGFA and IL-6, while assessments of HCC specimens confirmed a positive correlation between CCL16 expression and IL-6 and VEGFA levels. Collectively, our study highlights oncogenic role of CCL16 in hepatocarcinogenesis and provides a foundational basis for novel therapeutic interventions targeting the CCL16/CCR1/CCR5 axis.

Chemokine CX3CL1 (Fractalkine) Signaling and Diabetic Encephalopathy

Diabetes mellitus (DM) is the most common metabolic disease in humans, and its prevalence is increasing worldwide in parallel with the obesity pandemic. A lack of insulin or insulin resistance, and consequently hyperglycemia, leads to many systemic disorders, among which diabetic encephalopathy (DE) is a long-term complication of the central nervous system (CNS), characterized by cognitive impairment and motor dysfunctions. The role of oxidative stress and neuroinflammation in the pathomechanism of DE has been proven. Fractalkine (CX3CL1) has unique properties as an adhesion molecule and chemoattractant, and by acting on its only receptor, CX3CR1, it regulates the activity of microglia in physiological states and neuroinflammation. Depending on the clinical context, CX3CL1-CX3CR1 signaling may have neuroprotective effects by inhibiting the inflammatory process in microglia or, conversely, maintaining/intensifying inflammation and neurotoxicity. This review discusses the evidence supporting that the CX3CL1-CX3CR1 pair is neuroprotective and other evidence that it is neurotoxic. Therefore, interrupting the vicious cycle within neuron-microglia interactions by promoting neuroprotective effects or inhibiting the neurotoxic effects of the CX3CL1-CX3CR1 signaling axis may be a therapeutic goal in DE by limiting the inflammatory response. However, the optimal approach to prevent DE is simply tight glycemic control, because the elimination of dysglycemic states in the CNS abolishes the fundamental mechanisms that induce this vicious cycle.

Circulating Chemokines and Short- and Long-Term Outcomes After Ischemic Stroke

Chemokines are vital in post-cerebral ischemia inflammatory reactions. We investigate the possible relationship between plasma chemokines and short-term and long-term outcomes after stroke. This study included 235 patients (median age, 72 years; 49.8% female) suffering from ischemic stroke, or transient ischemic attack admitted to the hospital within 24 h of onset. We evaluated chemokines CCL2, CCL5, CXCL8, CXCL9, and CXCL10 in plasma samples collected upon admission. Further, we assessed functional outcomes at 3- and 12-months, all-cause fatality over 5 years, and episodes of delirium within the first 7 days of admission. Multivariate analysis revealed an association between higher CXCL10 levels and an increased risk of poor functional outcomes at 3 months (OR: 3.02, 95%CI: 1.22-7.46, p = 0.016) and 12 months (OR: 2.32, 95%CI: 1.03-5.26, p = 0.043), as well as an increased death risk (HR: 1.79, 95%CI: 1.04-3.07, p = 0.036). High CXCL8 levels independently predicted poor functional outcomes at 12 months (OR: 2.69, 95%CI: 1.39-6.31, p = 0.005) and a higher 5-year case fatality rate (HR: 1.90, 95%CI: 1.23-2.93, p = 0.004). Elevated CXCL9 levels also predicted unfavourable functional outcomes at 12 months (OR: 2.45, 95%CI: 1.07-5.61, p = 0.034). In univariate analysis, increased levels of CXCL8, CXCL9, and CXCL10 showed an association with delirium, although this link was not evident in the multivariate analysis. Plasma CXCL8 and CXCL10 show potential as prognostic biomarkers for stroke outcomes and as therapeutic targets suitable for reverse translation.

Zika virus infection suppresses CYP24A1 and CAMP expression in human monocytes

Monocytes are the primary targets of Zika virus (ZIKV) and are associated with ZIKV pathogenesis. Currently, there is no effective treatment for ZIKV infection. It is known that 1,25-dihydroxy vitamin D3 (VitD3) has strong antiviral activity in dengue virus-infected macrophages, but it is unknown whether VitD3 inhibits ZIKV infection in monocytes. We investigated the relationship between ZIKV infection and the expression of genes of the VitD3 pathway, as well as the inflammatory response of infected monocytes in vitro. ZIKV replication was evaluated using a plaque assay, and VitD3 pathway gene expression was analyzed by RT-qPCR. Pro-inflammatory cytokines/chemokines were quantified using ELISA. We found that VitD3 did not suppress ZIKV replication. The results showed a significant decrease in the expression of vitamin D3 receptor (VDR), cytochrome P450 family 24 subfamily A member 1 (CYP24A1), and cathelicidin antimicrobial peptide (CAMP) genes upon ZIKV infection. Treatment with VitD3 was unable to down-modulate production of pro-inflammatory cytokines, except TNF-α, and chemokines. This suggests that ZIKV infection inhibits the expression of VitD3 pathway genes, thereby preventing VitD3-dependent inhibition of viral replication and the inflammatory response. This is the first study to examine the effects of VitD3 in the context of ZIKV infection, and it has important implications for the role of VitD3 in the control of viral replication and inflammatory responses during monocyte infection.

Structural basis of chemokine recognition by the class A3 tick evasin EVA-ACA1001

Ticks produce chemokine-binding proteins, known as evasins, in their saliva to subvert the host's immune response. Evasins bind to chemokines and thereby inhibit the activation of their cognate chemokine receptors, thus suppressing leukocyte recruitment and inflammation. We recently described subclass A3 evasins, which, like other class A evasins, exclusively target CC chemokines but appear to use a different binding site architecture to control target selectivity among CC chemokines. We now describe the structural basis of chemokine recognition by the class A3 evasin EVA-ACA1001. EVA-ACA1001 binds to almost all human CC chemokines and inhibits receptor activation. Truncation mutants of EVA-ACA1001 showed that, unlike class A1 evasins, both the N- and C-termini of EVA-ACA1001 play minimal roles in chemokine binding. To understand the structural basis of its broad chemokine recognition, we determined the crystal structure of EVA-ACA1001 in complex with the human chemokine CCL16. EVA-ACA1001 forms backbone-backbone interactions with the CC motif of CCL16, a conserved feature of all class A evasin-chemokine complexes. A hydrophobic pocket in EVA-ACA1001, formed by several aromatic side chains and the unique disulfide bond of class A3 evasins, accommodates the residue immediately following the CC motif (the "CC + 1 residue") of CCL16. This interaction is shared with EVA-AAM1001, the only other class A3 evasins characterized to date, suggesting it may represent a common mechanism that accounts for the broad recognition of CC chemokines by class A3 evasins.

An overview of current advances in perinatal alcohol exposure and pathogenesis of fetal alcohol spectrum disorders

The adverse use of alcohol is a serious global public health problem. Maternal alcohol consumption during pregnancy usually causes prenatal alcohol exposure (PAE) in the developing fetus, leading to a spectrum of disorders known as fetal alcohol spectrum disorders (FASD) and even fetal alcohol syndrome (FAS) throughout the lifelong sufferers. The prevalence of FASD is approximately 7.7 per 1,000 worldwide, and is even higher in developed regions. Generally, Ethanol in alcoholic beverages can impair embryonic neurological development through multiple pathways leading to FASD. Among them, the leading mechanism of FASDs is attributed to ethanol-induced neuroinflammatory damage to the central nervous system (CNS). Although the underlying molecular mechanisms remain unclear, the remaining multiple pathological mechanisms is likely due to the neurotoxic damage of ethanol and the resultant neuronal loss. Regardless of the molecular pathway, the ultimate outcome of the developing CNS exposed to ethanol is almost always the destruction and apoptosis of neurons, which leads to the reduction of neurons and further the development of FASD. In this review, we systematically summarize the current research progress on the pathogenesis of FASD, which hopefully provides new insights into differential early diagnosis, treatment and prevention for patents with FASD.

The glycosaminoglycan-binding chemokine fragment CXCL9(74-103) reduces inflammation and tissue damage in mouse models of coronavirus infection

Introduction

Pulmonary diseases represent a significant burden to patients and the healthcare system and are one of the leading causes of mortality worldwide. Particularly, the COVID-19 pandemic has had a profound global impact, affecting public health, economies, and daily life. While the peak of the crisis has subsided, the global number of reported COVID-19 cases remains significantly high, according to medical agencies around the world. Furthermore, despite the success of vaccines in reducing the number of deaths caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there remains a gap in the treatment of the disease, especially in addressing uncontrolled inflammation. The massive recruitment of leukocytes to lung tissue and alveoli is a hallmark factor in COVID-19, being essential for effectively responding to the pulmonary insult but also linked to inflammation and lung damage. In this context, mice models are a crucial tool, offering valuable insights into both the pathogenesis of the disease and potential therapeutic approaches.

Methods

Here, we investigated the anti-inflammatory effect of the glycosaminoglycan (GAG)-binding chemokine fragment CXCL9(74-103), a molecule that potentially decreases neutrophil transmigration by competing with chemokines for GAG-binding sites, in two models of pneumonia caused by coronavirus infection.

Results

In a murine model of betacoronavirus MHV-3 infection, the treatment with CXCL9(74-103) decreased the accumulation of total leukocytes, mainly neutrophils, to the alveolar space and improved several parameters of lung dysfunction 3 days after infection. Additionally, this treatment also reduced the lung damage. In the SARS-CoV-2 model in K18-hACE2-mice, CXCL9(74-103) significantly improved the clinical manifestations of the disease, reducing pulmonary damage and decreasing viral titers in the lungs.

Discussion

These findings indicate that CXCL9(74-103) resulted in highly favorable outcomes in controlling pneumonia caused by coronavirus, as it effectively diminishes the clinical consequences of the infections and reduces both local and systemic inflammation.

B cells and the stressed brain: emerging evidence of neuroimmune interactions in the context of psychosocial stress and major depression

The immune system has emerged as a key regulator of central nervous system (CNS) function in health and in disease. Importantly, improved understanding of immune contributions to mood disorders has provided novel opportunities for the treatment of debilitating stress-related mental health conditions such as major depressive disorder (MDD). Yet, the impact to, and involvement of, B lymphocytes in the response to stress is not well-understood, leaving a fundamental gap in our knowledge underlying the immune theory of depression. Several emerging clinical and preclinical findings highlight pronounced consequences for B cells in stress and MDD and may indicate key roles for B cells in modulating mood. This review will describe the clinical and foundational observations implicating B cell-psychological stress interactions, discuss potential mechanisms by which B cells may impact brain function in the context of stress and mood disorders, describe research tools that support the investigation of their neurobiological impacts, and highlight remaining research questions. The goal here is for this discussion to illuminate both the scope and limitations of our current understanding regarding the role of B cells, stress, mood, and depression.

Antiviral treatment significantly reduces the levels of CXCL9, CXCL10 and CXCL11 in chronic hepatitis C

In this study, we aimed to elucidate the changes in the immune response during antiviral treatment of patients with chronic hepatitis C, with an emphasis on the chemokine dynamics and their association with liver fibrosis. Serum concentrations of 12 chemokines. (CCL2, CCL3, CCL4, CCL11, CCL17, CCL20, CXCL1, CXCL5, CXCL8, CXCL9, CXCL10 and CXCL11) were measured in 32 patients with chronic hepatitis C before direct-acting antiviral treatment and after sustained virological response using bead-based flow cytometry. Chemokine levels were also measured in 14 sex- and age-matched healthy individuals. Concentrations of CXCL9, CXCL10, CXCL11 and CCL20 were significantly higher in chronic hepatitis C patients before direct-acting antiviral treatment compared to healthy individuals. We also observed a significant reduction in CXCL9, CXCL10 and CXCL11 levels after sustained virological response. Furthermore, we demonstrated a strong positive correlation between CXCL9, CXCL10 and CXCL11 levels before antiviral treatment. When considering liver fibrosis, we found significantly higher levels of CXCL10 and lower levels of CCL17 and CXCL5 in pre-treatment patients with severe fibrosis. None of the analysed chemokines were able to predict METAVIR fibrosis score reduction after sustained virological response. The results of this study emphasize the importance of proinflammatory pathways in liver fibrosis immunopathology during chronic hepatitis C. Finally, our results also characterized CXCL10 as the chemokine which most accurately distinguished pre-treatment CHC patients and healthy individuals.

Analysis of the mucosal chemokines CCL28, CXCL14, and CXCL17 in dry eye disease: An in vitro and clinical investigation

Mucosal chemokines have antimicrobial properties and play an important role in mucosal immunity. However, little is known about their expression on the ocular surface. This study aimed to analyze the expression of the mucosal chemokines CCL28, CXCL14 and CXCL17 in corneal and conjunctival epithelial cells under in vitro dry eye (DE) conditions, and in conjunctival samples from healthy subjects and DE patients. Human corneal epithelial cells (HCE) and immortalized human conjunctival epithelial cells (IM-HConEpiC) were incubated under hyperosmolar (400-500 mOsM) or inflammatory (TNF-α 25 ng/mL) conditions for 6 h and 24 h to measure CCL28, CXCL14, and CXCL17 gene expression by RT-PCR and their secretion by immunobead-based analysis (CCL28, CXCL14) and ELISA (CXCL17). Additionally, twenty-seven DE patients and 13 healthy subjects were included in this study. DE-related questionnaires (OSDI, mSIDEQ and NRS) evaluated symptomatology. Ocular surface integrity was assessed using vital staining. Tactile sensitivity was measured with Cochet-Bonnet esthesiometer, and mechanic and thermal (heat and cold) sensitivity using Belmonte's non-contact esthesiometer. Subbasal nerve plexus and dendritic cell density were analyzed by in vivo confocal microscopy. Conjunctival cells from participants were collected by impression cytology to measure mucosal chemokines gene expression by RT-PCR. Our results showed that HCE and IM-HConEpiC cells increased CCL28, CXCL14, and CXCL17 secretion under hyperosmolar conditions. The gene expression of CCL28 was significantly upregulated in conjunctival samples from DE patients. CCL28 expression correlated positively with symptomatology, corneal staining, heat sensitivity threshold, and dendritic cell density. CXCL14 expression correlated positively with age, ocular pain, conjunctival staining, tactile sensitivity, and image reflectivity. CXCL17 expression correlated positively with corneal staining. These results suggest that corneal and conjunctival epithelial cells could be a source of CCL28, CXCL14, and CXCL17 on the ocular surface and that CCL28 might be involved in DE pathogenesis.

The origin, evolution, and molecular diversity of the chemokine system

Chemokine signalling performs key functions in cell migration via chemoattraction, such as attracting leukocytes to the site of infection during host defence. The system consists of a ligand, the chemokine, usually secreted outside the cell, and a chemokine receptor on the surface of a target cell that recognises the ligand. Several noncanonical components interact with the system. These include a variety of molecules that usually share some degree of sequence similarity with canonical components and, in some cases, are known to bind to canonical components and/or to modulate cell migration. Whereas canonical components have been described in vertebrate lineages, the distribution of the noncanonical components is less clear. Uncertainty over the relationships between canonical and noncanonical components hampers our understanding of the evolution of the system. We used phylogenetic methods, including gene-tree to species-tree reconciliation, to untangle the relationships between canonical and noncanonical components, identify gene duplication events, and clarify the origin of the system. We found that unrelated ligand groups independently evolved chemokine-like functions. We found noncanonical ligands outside vertebrates, such as TAFA "chemokines" found in urochordates. In contrast, all receptor groups are vertebrate-specific and all-except ACKR1-originated from a common ancestor in early vertebrates. Both ligand and receptor copy numbers expanded through gene duplication events at the base of jawed vertebrates, with subsequent waves of innovation occurring in bony fish and mammals.

Do chemokine/chemokine receptor axes play paramount parts in trafficking and oriented locomotion of monocytes/macrophages toward the lungs of COVID-19 infected patients? A systematic review

The COVID-19 (coronavirus disease 2019) is a well-defined viral infection, resulting from SARS-CoV-2 (severe acute respiratory syndrome- coronavirus-2). The innate immune system serves as the first line of defense to limit viral spreading and subsequently stimulate adaptive immune responses by the prominent aids of its cellular and molecular arms. Monocytes are defined as the most prominent innate immune cells (IICs) that are reactive against invading pathogens. These cells support host protection against the virus that is mediated by several non-specific mechanisms such as phagocytosis, producing antiviral enzymes, and recruitment of immune cells toward and into the infected tissues. They have the ability to egress from blood and migrate to the SARS-CoV-2 infected regions by the aid of some defense-related functions like chemotaxis, which is mediated by chemical compounds, e.g., chemokines. Chemokines, in addition to their related ligands are categorized within the most important and deserved agents involved in oriented trafficking of monocytes/macrophages towards and within the lung parenchyma in both steady state and pathological circumstances, including COVID-19-raised infection. However, the overexpression of chemokines could have deleterious effects on various organs through the induction of cytokine storm and may be the most important leading mechanisms in the pathogenesis of COVID-19. Authors have aimed the current review article to describe present knowledge about the interplay between monocytes/macrophages and SARS-CoV-2 with a focus on the ability of IICs to migrate and home into the lung of COVID-19 patients through various chemokine-chemokine receptor axes to promote our understanding regarding this disease.

Progression of radio-labeled molecular imaging probes targeting chemokine receptors

Chemokine receptors are significantly expressed in the surface of most inflammatory cells and tumor cells. Guided by chemokines, inflammatory cells which express the relevant chemokine receptors migrate to inflammatory lesions and participate in the evolution of inflammation diseases. Similarly, driven by chemokines, immune cells infiltrate into tumor lesions not only induces alterations in the tumor microenvironment, disrupting the efficacy of tumor therapies, but also has the potential to selectively target tumoral cells and diminish tumor progression. Chemokine receptors, which are significantly expressed on the surface of tumor cell membranes, are regulated by chemokines and initiate tumor-associated signaling pathways within tumor cells, playing a complex role in tumor progression. Based on the antagonists targeting chemokine receptors, radionuclide-labeled molecular imaging probes have been developed for the emerging application of molecular imaging in diseases such as tumors and inflammation. The value and limitations of molecular probes in disease imaging are worth reviewing.

Fentanyl dysregulates neuroinflammation and disrupts blood-brain barrier integrity in HIV-1 Tat transgenic mice

Opioid overdose deaths have dramatically increased by 781% from 1999 to 2021. In the setting of HIV, opioid drug abuse exacerbates neurotoxic effects of HIV in the brain, as opioids enhance viral replication, promote neuronal dysfunction and injury, and dysregulate an already compromised inflammatory response. Despite the rise in fentanyl abuse and the close association between opioid abuse and HIV infection, the interactive comorbidity between fentanyl abuse and HIV has yet to be examined in vivo. The HIV-1 Tat-transgenic mouse model was used to understand the interactive effects between fentanyl and HIV. Tat is an essential protein produced during HIV that drives the transcription of new virions and exerts neurotoxic effects within the brain. The Tat-transgenic mouse model uses a glial fibrillary acidic protein (GFAP)-driven tetracycline promoter which limits Tat production to the brain and this model is well used for examining mechanisms related to neuroHIV. After 7 days of fentanyl exposure, brains were harvested. Tight junction proteins, the vascular cell adhesion molecule, and platelet-derived growth factor receptor-β were measured to examine the integrity of the blood brain barrier. The immune response was assessed using a mouse-specific multiplex chemokine assay. For the first time in vivo, we demonstrate that fentanyl by itself can severely disrupt the blood-brain barrier and dysregulate the immune response. In addition, we reveal associations between inflammatory markers and tight junction proteins at the blood-brain barrier.

The Involvement of Cysteine-X-Cysteine Motif Chemokine Receptors in Skin Homeostasis and the Pathogenesis of Allergic Contact Dermatitis and Psoriasis

Members of the C-X-C motif chemokine receptor (CXCR) superfamily play central roles in initiating the innate immune response in mammalian cells by orchestrating selective cell migration and immune cell activation. With its multilayered structure, the skin, which is the largest organ in the body, performs a crucial defense function, protecting the human body from harmful environmental threats and pathogens. CXCRs contribute to primary immunological defense; these receptors are differentially expressed by different types of skin cells and act as key players in initiating downstream innate immune responses. While the initiation of inflammatory responses by CXCRs is essential for pathogen elimination and tissue healing, overactivation of these receptors can enhance T-cell-mediated autoimmune responses, resulting in excessive inflammation and the development of several skin disorders, including psoriasis, atopic dermatitis, allergic contact dermatitis, vitiligo, autoimmune diseases, and skin cancers. In summary, CXCRs serve as critical links that connect innate immunity and adaptive immunity. In this article, we present the current knowledge about the functions of CXCRs in the homeostasis function of the skin and their contributions to the pathogenesis of allergic contact dermatitis and psoriasis. Furthermore, we will examine the research progress and efficacy of therapeutic approaches that target CXCRs.

A review of skin immune processes in acne

Acne vulgaris is one of the most prevalent skin conditions, affecting almost all teenagers worldwide. Multiple factors, including the excessive production of sebum, dysbiosis of the skin microbiome, disruption of keratinization within hair follicles, and local inflammation, are believed to trigger or aggravate acne. Immune activity plays a crucial role in the pathogenesis of acne. Recent research has improved our understanding of the immunostimulatory functions of microorganisms, lipid mediators, and neuropeptides. Additionally, significant advances have been made in elucidating the intricate mechanisms through which cutaneous innate and adaptive immune cells perceive and transmit stimulatory signals and initiate immune responses. However, our understanding of precise temporal and spatial patterns of immune activity throughout various stages of acne development remains limited. This review provides a comprehensive overview of the current knowledge concerning the immune processes involved in the initiation and progression of acne. Furthermore, we highlight the significance of detailed spatiotemporal analyses, including analyses of temporal dynamics of immune cell populations as well as single-cell and spatial RNA sequencing, for the development of targeted therapeutic and prevention strategies.

Lactobacillus johnsonii N6.2 phospholipids induce immature-like dendritic cells with a migratory-regulatory-like transcriptional signature

Shifts in the gut microbiota composition, called dysbiosis, have been directly associated with acute and chronic diseases. However, the underlying biological systems connecting gut dysbiosis to systemic inflammatory pathologies are not well understood. Phospholipids (PLs) act as precursors of both, bioactive inflammatory and resolving mediators. Their dysregulation is associated with chronic diseases including cancer. Gut microbial-derived lipids are structurally unique and capable of modulating host's immunity. Lactobacillus johnsonii N6.2 is a Gram-positive gut symbiont with probiotic characteristics. L. johnsonii N6.2 reduces the incidence of autoimmunity in animal models of Type 1 Diabetes and improves general wellness in healthy volunteers by promoting, in part, local and systemic anti-inflammatory responses. By utilizing bioassay-guided fractionation methods with bone marrow-derived dendritic cells (BMDCs), we report here that L. johnsonii N6.2 purified lipids induce a transcriptional signature that resembles that of migratory (mig) DCs. RNAseq-based analysis showed that BMDCs stimulated with L. johnsonii N6.2 total lipids upregulate maturation-mig related genes Cd86, Cd40, Ccr7, Icam1 along with immunoregulatory genes including Itgb8, Nfkbiz, Jag1, Adora2a, IL2ra, Arg1, and Cd274. Quantitative reverse transcription (qRT)-PCR analysis indicated that PLs are the bioactive lipids triggering the BMDCs response. Antibody-blocking of surface Toll-like receptor (TLR)2 resulted in boosted PL-mediated upregulation of pro-inflammatory Il6. Chemical inhibition of the IKKα kinase from the non-canonical NF-κB pathway specifically restricted upregulation of Il6 and Tnf. Phenotypically, PL-stimulated BMDCs displayed an immature like-phenotype with significantly increased surface ICAM-1. This study provides insight into the immunoregulatory capacity of Gram-positive, gut microbial-derived phospholipids on innate immune responses.

High density of CXCL12-positive immune cell infiltration predicts chemosensitivity and recurrence-free survival in ovarian carcinoma

BACKGROUND

Ovarian carcinoma is the most lethal gynecologic malignancy because of its late diagnosis, extremely high recurrence rate, and limited curative treatment options. In clinical practice, high-grade serous carcinoma (HGSC) predominates due to its frequency, high aggressiveness, and rapid development of drug resistance. Recent evidence suggests that CXCL12 is an important immunological factor in ovarian cancer progression. Therefore, we investigated the predictive and prognostic significance of the expression of this chemokine in tumor and immune cells in patients with HGSC.

METHODS

We studied a cohort of 47 primary high-grade serous ovarian carcinomas and their associated recurrences. A tissue microarray was constructed to evaluate the CXCL12 immunostained tumor tissue. CXCL12 expression was evaluated and statistically analyzed to correlate clinicopathologic data, overall survival, and recurrence-free survival.

RESULTS

A high proportion of CXCL12 + positive immune cells in primary ovarian serous carcinoma correlated significantly with chemosensitivity (p = 0.005), overall survival (p = 0.021), and longer recurrence-free survival (p = 0.038). In recurrent disease, high expression of CXCL12 was also correlated with better overall survival (p = 0.040). Univariate and multivariate analysis revealed that high CXCL12 + tumor-infiltrating immune cells (TICs) (HR 0.99, p = 0.042, HR 0.99, p = 0.023, respectively) and combined CXCL12 + /CD66b + infiltration (HR 0.15, p = 0.001, HR 0.13, p = 0.001, respectively) are independent favorable predictive markers for recurrence-free survival.

CONCLUSION

A high density of CXCL12 + TICs predicts a good response to chemotherapy, leading to a better overall survival and a longer recurrence-free interval. Moreover, with concomitant high CXCL12/CD66b TIC density, it is an independent favorable predictor of recurrence-free survival in patients with ovarian carcinoma.

Homeostatic chemokines as putative therapeutic targets in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal chronic interstitial lung disease (ILD) that affects lung mechanical functions and gas exchange. IPF is caused by increased fibroblast activity and collagen deposition that compromise the alveolar-capillary barrier. Identifying an effective therapy for IPF remains a clinical challenge. Chemokines are key proteins in cell communication that have functions in immunity as well as in tissue homeostasis, damage, and repair. Chemokine receptor signaling induces the activation and proliferation of lung-resident cells, including alveolar macrophages (AMs) and fibroblasts. AMs are an important source of chemokines and cytokines during IPF. We highlight the complexity of this system and, based on insights from genetic and transcriptomic studies, propose a new role for homeostatic chemokine imbalance in IPF, with implications for putative therapeutic targets.

Circ_0002295 facilitated myocardial fibrosis progression through the miR-1287/CXCR2 axis

Myocardial fibrosis (MF) is involved in hypertension, myocardial infarction and heart failure. It has been reported that circular RNA (circRNA) is a key regulatory factor of MF progression. In this study, we revealed that circ_0002295 and CXCR2 were elevated, and miR-1287 was reduced in MF patients. Knockdown of circ_0002295 effectively suppressed the proliferation, migration and MF progression. Circ_0002295 was the molecular sponge of miR-12878, and miR-1287 inhibitor reversed the biological functions of circ_0002295 on the myocardial fibrosis. CXCR2 was a target gene of miR-1287, and CXCR2 silencing relieved the impacts of miR-1287 inhibitor on cardiac myofibroblasts. Circ_0002295 promoted MF progression by regulating the miR-1287/CXCR2 axis, providing a possible circRNA-targeted therapy for MF.

Chemokines: A key driver for inflammation in protozoan infection

Chemokines belong to the group of small proteins within the cytokine family having strong chemo-attractant properties. In most cases, the strong immuno-modulatory role of chemokines is crucial for generating the immune response against pathogens in various protozoan diseases. In this review, we have given a brief update on the classification, characterization, homeostasis, transcellular migration, and immuno-modulatory role of chemokines. Here we will evaluate the potential role of chemokines and their regulation in various protozoan diseases. There is a significant direct relationship between parasitic infection and the recruitment of effector cells of the immune response. Chemokines play an indispensable role in mediating several defense mechanisms against infection, such as leukocyte recruitment and the generation of innate and cell-mediated immunity that aids in controlling/eliminating the pathogen. This process is controlled by the chemotactic movement of chemokines induced as a primary host immune response. We have also addressed that chemokine expressions during infection are time-dependent and orchestrated in a systematic pattern that ultimately assists in generating a protective immune response. Taken together, this review provides a systematic understanding of the complexity of chemokines profiles during protozoan disease conditions and the rationale of targeting chemokines for the development of therapeutic strategies.

Cytokine and Chemokine Production in Mice Inoculated with NVX-CoV2373 (Nuvaxovid®) in Comparison with Omicron BA.4/5 Bivalent BNT162b2 (Comirnaty®)

A recombinant SARS-CoV-2 spike protein vaccine (NVX-CoV2373) has been licensed and has a lesser incidence of adverse events. To know the immunological mechanisms of adverse events, the production of cytokines and chemokines was investigated in mice inoculated with NVX-CoV2373. Serum IL-6 was detected on Day 1 of the first and second doses and the IFN-γ, IL-4, IL-10, TNF-α, and IL-6 levels increased on Day 1 of the second dose at the inoculation site. The enhanced production of the inflammatory chemokines (CCL2), homeostatic chemokine (CXCL13), and Th2 chemokine (CCL17) was observed at the inoculation site on Day 1 of the second dose. These findings were compared with data obtained following inoculation with BNT162b2 bivalent vaccine containing omicron BA.4/5. Significantly lower levels of inflammatory chemokines were detected on Day 1 after the first dose of NVX-CoV2373 in sera and inoculation site than those following inoculation with bivalent BNT162b2 (p < 0.01), reflecting a lower incidence of adverse events after immunization with NVX-CoV2373 in humans. NVX-CoV2373 induced significantly higher concentrations of IFN-γ, TNF-α, and IL-10 at the inoculation site obtained on Day 1 of the second dose (p < 0.05). Significant higher levels of Th2 chemokines, CCL11 and CCL17, were induced at the inoculation site on Day 1 of the second dose (p < 0.01) and they explain the booster IgG EIA antibody response after the second dose of NVX-CoV2373.

Prognostic value of MTSS1 gene expression on acute leukemia patients outcome

Background: This study aimed to evaluate the prognostic value of the MTSS1 gene expression in patients with acute leukemia. Patients & methods: MTSS1 gene expression was quantified in 120 newly diagnosed acute leukemia patients, by quantitative reverse transcription PCR at diagnosis and after induction chemotherapy therapy. Results: Baseline MTSS1 gene expression was significantly higher in acute leukemia patients compared to the control group (p < 0.001). Acute leukemia patients with low baseline MTSS1 gene expression at diagnosis have significantly shorter overall survival and disease-free survival compared with those with higher expression (p < 0.001 for both). Conclusion: Downregulation of MTSS1 gene expression at diagnosis was associated with poor outcome in either cytogenetic acute myeloid leukemia or B-cell acute lymphoblastic leukemia.

Chemokine Binding to Tenascin-C Influences Chemokine-Induced Immune Cell Migration

Tenascin-C (TNC) is a complex glycoprotein of the extracellular matrix (ECM) involved in a plethora of (patho-)physiological processes, such as oncogenesis and inflammation. Since chemokines play an essential role in both disease processes, we have investigated here the binding of TNC to some of the key chemokines, namely CCL2, CCL26, CXCL8, CXCL10, and CXCL12. Thereby, a differential chemokine-TNC binding pattern was observed, with CCL26 exhibiting the highest and CCL2 the lowest affinity for TNC. Heparan sulfate (HS), another member of the ECM, proved to be a similarly high-affinity ligand of TNC, with a Kd value of 730 nM. Chemokines use glycosa-minoglycans such as HS as co-receptors to induce immune cell migration. Therefore, we assumed an influence of TNC on immune cell chemotaxis due to co-localization within the ECM. CCL26- and CCL2-induced mobilization experiments of eosinophils and monocytes, respectively, were thus performed in the presence and the absence of TNC. Pre-incubation of the immune cells with TNC resulted in a 3.5-fold increase of CCL26-induced eosinophil chemotaxis, whereas a 1.3-fold de-crease in chemotaxis was observed when monocytes were pre-incubated with CCL2. As both chemokines have similar HS binding but different TNC binding affinities, we speculate that TNC acts as an attenuator in monocyte and as an amplifier in eosinophil mobilization by impeding CCL2 from binding to HS on the one hand, and by reinforcing CCL26 to bind to HS on the other hand.

Investigating novel biomarkers in uterine corpus endometrial carcinoma: in silico analysis and clinical specimens validation via RT-qPCR and immunohistochemistry

The rising incidence and mortality rate of Uterine Corpus Endometrial Carcinoma (UCEC) pose significant health concerns. CC and CXC chemokines have been linked to tumorigenesis and cancer progression. Recognizing the growing significance of CC and CXC chemokines' diagnostic and prognostic significance in diverse cancer types, our objective was to comprehensively analyze the diagnostic and prognostic values of hub genes from the CC and CXC chemokines in UCEC, utilizing both in silico and clinical samples and cell lines-based approaches. In silico analyses include STRING, Cytoscape, Cytohubba, The Cancer Genome Atlas (TCGA) datasets analysis via the UALCAN, GEPIA, OncoDB, and MuTarget, SurvivalGenie, MEXPRESS, cBioPoratal, TIMER, ENCORI, and DrugBank. Meanwhile, clinical samples and cell lines based analyses include Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), targeted bisulfite sequencing (bisulfite-seq) analysis, and immunohistochemistry (IHC). Through present study, we identified CCL25 (CC motif chemokine ligand 25), CXCL10 (C-X-C motif chemokine ligand 10), CXCL12 (C-X-C motif chemokine ligand 12), and CXCL16 (C-X-C motif chemokine ligand 16) as crucial hub genes among the CC and CXC chemokines. Analyzing the expression data from TCGA, we observed a significant up-regulation of CCL25, CXCL10, and CXCL16 in UCEC samples compared to controls. In contrast, we noted a significant down-regulation of CXCL12 expression in UCEC samples. On clinical UCEC samples and cell lines analysis, the significant higher expression of CCL25, CXCL10, and CXCL16 and significant lower expression of CXCL12 were also denoted in UCEC samples than the controls via RT-qPCR and IHC analyses. Moreover, in silico analysis also confirmed the abnormal promoter methylation levels of the hub genes in TCGA UCEC samples, which was later validated by the clinical samples using targeted based bisulfite-seq analysis. In addition, various additional aspects of the CCL25, CXCL10, CXCL12, and CXCL16 have also been uncovered in UCEC during the present study. Our findings offer novel insights that contribute to the clinical utility of CCL25, CXCL10, CXCL12, and CXCL16 chemokines as potential diagnostic and prognostic biomarkers in UCEC.

Development of a chronic focal equine arteritis virus infection of a male reproductive tract cell line

Equine arteritis virus (EAV) is an Alphaarterivirus (family Arteriviridae, order Nidovirales) that frequently causes an influenza-like illness in adult horses, but can also cause the abortions in mares and death of newborn foals. Once primary infection has been established, EAV can persist in the reproductive tract of some stallions. However, the mechanisms enabling this persistence, which depends on testosterone, remain largely unknown. We aimed to establish an in vitro model of non-cytopathic EAV infection to study viral persistence. In this work, we infected several cell lines originating from the male reproductive tract of different species. EAV infection was fully cytopathic for 92BR (donkey cells) and DDT1 MF-2 (hamster cells) cells, and less cytopathic for PC-3 cells (human cells); ST cells (porcine cells) seemed to eliminate the virus; LNCaP (human cells) and GC-1 spg (murine cells) cells were not permissive to EAV infection; finally, TM3 cells (murine cells) were permissive to EAV infection without any overt cytopathic effects. Infected TM3 cells can be maintained at least 7 days in culture without any subculture. They can also be subcultured over 39 days (subculturing them at 1:2 the first time at 5 dpi and then every 2-3 days), but in this case, the percentage of infected cells remains low. Infected TM3 cells may therefore provide a new model to study the host-pathogen interactions and to help determine the mechanisms involved in EAV persistence in stallion reproductive tract.

Interferon lambda modulates proinflammatory cytokines production in PBMCs from patients with chronic kidney disease

BACKGROUND

CKD is a major cause of morbidity and mortality worldwide. Considerable evidence now indicates that renal inflammation plays a central role in the initiation and progression of CKD. Recent investigations have demonstrated that IFNλ plays an important role in the pathogenesis of autoimmune and inflammatory diseases. However, the association of IFNλ with CKD is still poorly understood.

OBJECTIVE

To analyze the correlation between IFNλ levels and pro-inflammatory cytokines, and to investigate the effect of IFNλ on PBMCs in patients with CKD.

METHODS

PBMCs were harvested from patients with CKD and healthy controls for measuring the expression level of inflammatory cytokines by RT-qPCR. Spearman correlation test was used to analyze correlation between IFNλ and cytokines as well as eGFR. PBMCs from healthy individuals and CKD patients were subjected to IFNλ protein stimulation. IL6, TNFα, IL10, ISG15 and MX1 mRNA level were measured by RT-PCR, STAT1 and phosphorylated STAT1 protein level were measured by Western blot.

RESULTS

Patients with CKD showed higher levels of IFNλ in PBMCs compared to healthy controls. IFNλ mRNA levels were associated with cytokines and eGFR. The transcription of IL6, TNFα, and IL10 was significantly increased in healthy human PBMCs after IFNλ stimulation. In addition, IFNλ acts on PBMCs by p-STAT1 and ISG15 as well as MX1.

CONCLUSION

High expression of IFNλ was found in CKD patients and was associated with eGFR and disease-related cytokines. More importantly, IFNλ promoted the expression of pro-inflammatory cytokines in PBMCs, suggesting a potential pro-inflammatory role of IFNλ in CKD.

Unbiased chemokine receptor screening reveals similar efficacy of lymph node- and tumor-targeted T cell immunotherapy

Localization is a crucial prerequisite for immune cell function and solid tumors evade immune control by modulating immune cell infiltration into the tumor stroma. Immunosuppressive cells like regulatory T cells are attracted, while cytotoxic CD8+ T cells are excluded. Engineering CD8+ T cells with chemokine receptors is a potent strategy to turn this mechanism of directed immune cell recruitment against the tumor. Here, we utilized fluorescent tagging to track the migratory behavior of tumor-specific T cells engineered with a library of all murine chemokine receptors in vivo. We then asked whether chemokine receptor-mediated redirection of antigen-specific T cells into tumors or tumor-draining lymph nodes showed superior anti-tumoral activity. We found that both targeting approaches showed higher therapeutic efficacy than control T cells. However, multiple receptors conveying the same homing pattern did not augment infiltration. Instead, in the MC38 colon carcinoma model, anti-tumoral efficacy as well as lymph node vs. tumor-homing patterns were mostly driven by CCR4 and CCR6, respectively. Overall, our data, based on fluorescent receptor tagging, identify the tumor-draining lymph node and the tumor itself as viable targets for chemokine receptor-mediated enhancement of adoptive T cell therapy.

Trinity of inflammation, innate immune cells and cross-talk of signalling pathways in tumour microenvironment

Unresolved inflammation is a pathological consequence of persistent inflammatory stimulus and perturbation in regulatory mechanisms. It increases the risk of tumour development and orchestrates all stages of tumorigenesis in selected organs. In certain cancers, inflammatory processes create the appropriate conditions for neoplastic transformation. While in other types, oncogenic changes pave the way for an inflammatory microenvironment that leads to tumour development. Of interest, hallmarks of tumour-promoting and cancer-associated inflammation are striking similar, sharing a complex network of stromal (fibroblasts and vascular cells) and inflammatory immune cells that collectively form the tumour microenvironment (TME). The cross-talks of signalling pathways initially developed to support homeostasis, change their role, and promote atypical proliferation, survival, angiogenesis, and subversion of adaptive immunity in TME. These transcriptional and regulatory pathways invariably contribute to cancer-promoting inflammation in chronic inflammatory disorders and foster "smouldering" inflammation in the microenvironment of various tumour types. Besides identifying common target sites of numerous cancer types, signalling programs and their cross-talks governing immune cells' plasticity and functional diversity can be used to develop new fate-mapping and lineage-tracing mechanisms. Here, we review the vital molecular mechanisms and pathways that establish the connection between inflammation and tumour development, progression, and metastasis. We also discussed the cross-talks between signalling pathways and devised strategies focusing on these interaction mechanisms to harness synthetic lethal drug combinations for targeted cancer therapy.

New genetic and epigenetic insights into the chemokine system: the latest discoveries aiding progression toward precision medicine

Over the past thirty years, the importance of chemokines and their seven-transmembrane G protein-coupled receptors (GPCRs) has been increasingly recognized. Chemokine interactions with receptors trigger signaling pathway activity to form a network fundamental to diverse immune processes, including host homeostasis and responses to disease. Genetic and nongenetic regulation of both the expression and structure of chemokines and receptors conveys chemokine functional heterogeneity. Imbalances and defects in the system contribute to the pathogenesis of a variety of diseases, including cancer, immune and inflammatory diseases, and metabolic and neurological disorders, which render the system a focus of studies aiming to discover therapies and important biomarkers. The integrated view of chemokine biology underpinning divergence and plasticity has provided insights into immune dysfunction in disease states, including, among others, coronavirus disease 2019 (COVID-19). In this review, by reporting the latest advances in chemokine biology and results from analyses of a plethora of sequencing-based datasets, we outline recent advances in the understanding of the genetic variations and nongenetic heterogeneity of chemokines and receptors and provide an updated view of their contribution to the pathophysiological network, focusing on chemokine-mediated inflammation and cancer. Clarification of the molecular basis of dynamic chemokine-receptor interactions will help advance the understanding of chemokine biology to achieve precision medicine application in the clinic.

ELMO1 Deficiency Reduces Neutrophil Chemotaxis in Murine Peritonitis

Peritoneal inflammation remains a major cause of treatment failure in patients with kidney failure who receive peritoneal dialysis. Peritoneal inflammation is characterized by an increase in neutrophil infiltration. However, the molecular mechanisms that control neutrophil recruitment in peritonitis are not fully understood. ELMO and DOCK proteins form complexes which function as guanine nucleotide exchange factors to activate the small GTPase Rac to regulate F-actin dynamics during chemotaxis. In the current study, we found that deletion of the Elmo1 gene causes defects in chemotaxis and the adhesion of neutrophils. ELMO1 plays a role in the fMLP-induced activation of Rac1 in parallel with the PI3K and mTORC2 signaling pathways. Importantly, we also reveal that peritoneal inflammation is alleviated in Elmo1 knockout mice in the mouse model of thioglycollate-induced peritonitis. Our results suggest that ELMO1 functions as an evolutionarily conserved regulator for the activation of Rac to control the chemotaxis of neutrophils both in vitro and in vivo. Our results suggest that the targeted inhibition of ELMO1 may pave the way for the design of novel anti-inflammatory therapies for peritonitis.

Autoantibodies against chemokines post-SARS-CoV-2 infection correlate with disease course

Infection with severe acute respiratory syndrome coronavirus 2 associates with diverse symptoms, which can persist for months. While antiviral antibodies are protective, those targeting interferons and other immune factors are associated with adverse coronavirus disease 2019 (COVID-19) outcomes. Here we discovered that antibodies against specific chemokines were omnipresent post-COVID-19, were associated with favorable disease outcome and negatively correlated with the development of long COVID at 1 yr post-infection. Chemokine antibodies were also present in HIV-1 infection and autoimmune disorders, but they targeted different chemokines compared with COVID-19. Monoclonal antibodies derived from COVID-19 convalescents that bound to the chemokine N-loop impaired cell migration. Given the role of chemokines in orchestrating immune cell trafficking, naturally arising chemokine antibodies may modulate the inflammatory response and thus bear therapeutic potential.

Sweetener System Intervention Shifted Neutrophils from Homeostasis to Priming

BACKGROUND

Non-nutritive sweeteners (NNS) are part of personalized nutrition strategies supporting healthy glycemic control. In contrast, the consumption of non-nutritive sweeteners has been related to person-specific and microbiome-dependent glycemic impairments. Reports on the effects of NNS on our highly individual cellular immune system are sparse. The recent identification of taste receptor expression in a variety of immune cells, however, suggested their immune-modulatory relevance.

METHODS

We studied the influence of a beverage-typical NNS system on the transcriptional profiling of sweetener-cognate taste receptors, selected cytokines and their receptors, and on Ca²⁺ signaling in isolated blood neutrophils. We determined plasma concentrations of saccharin, acesulfame-K, and cyclamate by HPLC-MS/MS, upon ingestion of a soft drink-typical sweetener surrogate. In an open-labeled, randomized intervention study, we determined pre- versus post-intervention transcript levels by RT-qPCR of sweetener-cognate taste receptors and immune factors.

RESULTS

Here we show that the consumption of a food-typical sweetener system modulated the gene expression of cognate taste receptors and induced the transcriptional regulation signatures of early homeostasis- and late receptor/signaling- and inflammation-related genes in blood neutrophils, shifting their transcriptional profile from homeostasis to priming. Notably, sweeteners at postprandial plasma concentrations facilitated fMLF (N-formyl-Met-Leu-Phe)-induced Ca²⁺ signaling.

CONCLUSIONS

Our results support the notion of sweeteners priming neutrophils to higher alertness towards their adequate stimuli.

A review of the pleiotropic actions of the IFN-inducible CXC chemokine receptor 3 ligands in the synovial microenvironment

Chemokines are pivotal players in instigation and perpetuation of synovitis through leukocytes egress from the blood circulation into the inflamed articulation. Multitudinous literature addressing the involvement of the dual-function interferon (IFN)-inducible chemokines CXCL9, CXCL10 and CXCL11 in diseases characterized by chronic inflammatory arthritis emphasizes the need for detangling their etiopathological relevance. Through interaction with their mutual receptor CXC chemokine receptor 3 (CXCR3), the chemokines CXCL9, CXCL10 and CXCL11 exert their hallmark function of coordinating directional trafficking of CD4+ TH1 cells, CD8+ T cells, NK cells and NKT cells towards inflammatory niches. Among other (patho)physiological processes including infection, cancer, and angiostasis, IFN-inducible CXCR3 ligands have been implicated in autoinflammatory and autoimmune diseases. This review presents a comprehensive overview of the abundant presence of IFN-induced CXCR3 ligands in bodily fluids of patients with inflammatory arthritis, the outcomes of their selective depletion in rodent models, and the attempts at developing candidate drugs targeting the CXCR3 chemokine system. We further propose that the involvement of the CXCR3 binding chemokines in synovitis and joint remodeling encompasses more than solely the directional ingress of CXCR3-expressing leukocytes. The pleotropic actions of the IFN-inducible CXCR3 ligands in the synovial niche reiteratively illustrate the extensive complexity of the CXCR3 chemokine network, which is based on the intercommunion of IFN-inducible CXCR3 ligands with distinct CXCR3 isoforms, enzymes, cytokines, and infiltrated and resident cells present in the inflamed joints.

Identification of immune associated potential molecular targets in proliferative diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes and causes of blindness in developed countries. Our study was designed to identify immune-related genes involved in the progression of proliferative diabetic retinopathy (PDR).

METHODS

The "GSE102485" dataset of neovascular membrane samples (NVMs) from type 1 and 2 diabetes mellitus patients was downloaded from the Gene Expression Omnibus database. Functional enrichment analyses, protein-protein interaction network (PPI) construction, and module analysis of immune pathways in NVMs and controls were conducted via Gene Set Enrichment Analysis and Metascape.

RESULTS

The significantly upregulated hallmark gene sets in DR2 and DR1 groups were involved in five immune pathways. Only CCR4, CXCR6, C3AR1, LPAR1, C5AR1, and P2RY14 were not previously reported in the context of PDR molecular pathophysiology. Except for P2RY14, all of the above were upregulated in retinal samples from experimental diabetes mouse models and human retina microvascular endothelial cells (HRMECs) treated with high glucose (HG) by quantitative Real Time Polymerase Chain Reaction (qRT-PCR).

CONCLUSION

The genes identified herein provide insight into immune-related differential gene expression during DR progression.

The roles of chemokines following intracerebral hemorrhage in animal models and humans

Intracerebral hemorrhage (ICH) is one common yet devastating stroke subtype, imposing considerable burdens on families and society. Current guidelines are limited to symptomatic treatments after ICH, and the death rate remains significant in the acute stage. Thus, it is crucial to promote research to develop new targets on brain injury after ICH. In response to hematoma formation, amounts of chemokines are released in the brain, triggering the infiltration of resident immune cells in the brain and the chemotaxis of peripheral immune cells via the broken blood-brain barrier. During the past decades, mounting studies have focused on the roles of chemokines and their receptors in ICH injury. This review summarizes the latest advances in the study of chemokine functions in the ICH. First, we provide an overview of ICH epidemiology and underlying injury mechanisms in the pathogenesis of ICH. Second, we introduce the biology of chemokines and their receptors in brief. Third, we outline the roles of chemokines in ICH according to subgroups, including CCL2, CCL3, CCL5, CCL12, CCL17, CXCL8, CXCL12, and CX3CL1. Finally, we summarize current drug usage targeting chemokines in ICH and other cardio-cerebrovascular diseases. This review discusses the expressions of these chemokines and receptors under normal or hemorrhagic conditions and cell-specific sources. Above all, we highlight the related data of these chemokines in the progression and outcomes of the ICH disease in preclinical and clinical studies and point to therapeutic opportunities targeting chemokines productions and interactions in treating ICH, such as accelerating hematoma absorption and alleviating brain edema.

Elevated levels of several chemokines in the cerebrospinal fluid of patients with subarachnoid hemorrhage are associated with worse clinical outcome

BACKGROUND

Chemokines are small cytokines that exert chemotactic actions on immune cells and are involved in many inflammatory processes. The present study aims to provide insight in the role of this relatively unexplored family of proteins in the inflammatory pathophysiology of subarachnoid hemorrhage (SAH).

MATERIALS AND METHODS

Cerebrospinal fluid of 29 patients (17 female; mean age 57 years) was collected at days 1, 4 and 10 after SAH, centrifuged and frozen at -70°C. Analysis of 92 inflammation-related proteins was performed using Target 96 Inflammation ® assay (Olink Proteomics, Uppsala, Sweden) based on Proximity Extension Assay technology. The panel included 20 chemokines (CCL2 (or MCP-1), CCL3, CCL4, CCL7 (or MCP-3), CCL8 (or MCP-2), CCL11 (or Eotaxin), CCL13 (or MCP-4), CCL19, CCL20, CCL23, CCL25, CCL28, CXCL1, CXCL5, CXCL6, CXCL8 (or IL-8), CXCL9, CXCL10, CXCL11 and CX3CL1 (or Fractalkine)) that were analyzed for their temporal patterns of expression and compared in dichotomized clinical groups based on World Federation of Neurosurgical Societies (WFNS) admission score and amount of blood on admission CT based on Fisher scale; presence of delayed cerebral ischemia(DCI)/delayed ischemic neurological deficit (DIND); and clinical outcome based on Glasgow Outcome Scale. Protein expression levels were provided in output unit Normalized Protein Expression (NPX). ANOVA models were used for statistical analyses.

RESULTS

Four temporal patterns of expression were observed (i.e., early, middle, late peak and no peak). Significantly higher day 10 mean NPX values were observed in patients with poor outcome (GOS 1-3) for chemokines CCL2, CCL4, CCL7, CCL11, CCL13, CCL19, CCL20, CXCL1, CXCL5, CXCL6 and CXCL8. In the WFNS 4-5 group, CCL11 showed significantly higher day 4 and day 10 mean NPX values and CCL25 significantly higher day 4 values. In patients with SAH Fisher 4, CCL11 showed significantly higher mean NPX values on days 1, 4 and 10. Finally, patients with DCI/DIND had significantly higher day 4 mean NPX values of CXCL5.

CONCLUSION

Higher levels of multiple chemokines at the late stage of SAH seemed to correlate with worse clinical outcome. A few chemokines correlated with WFNS score, Fisher score and occurrence of DCI/DIND. Chemokines may be useful as biomarkers for describing the pathophysiology and prognosis of SAH. Further studies are needed to better understand their exact mechanism of action in the inflammatory cascade.

Methods to Assess Chemokine Binding and Anti-chemotactic Activity of Virus Proteins

Chemokines are key instigators of inflammatory and immune responses. Viruses can suppress these responses by secreting proteins that interfere with chemokine action. These proteins bind to chemokines and block the host's ability to recruit immune cells to sites of infection, thus facilitating virus replication and spread. When produced recombinantly, chemokine binding proteins provide a formidable resource to deploy against human disease. Here, we describe an enzyme-linked immunosorbent inhibition assay and a chemotaxis inhibition assay that are employed to assess the chemokine binding strength and anti-chemotactic activity of viral proteins. These assays are quick and reproducible, and are thus ideal for screening putative or modified chemokine binding proteins as the first step in their development as therapeutics.

Discovery of grey matter lesion-related immune genes for diagnostic prediction in multiple sclerosis

Background

Multiple sclerosis (MS) is a chronic debilitating disease characterized by inflammatory demyelination of the central nervous system. Grey matter (GM) lesions have been shown to be closely related to MS motor deficits and cognitive impairment. In this study, GM lesion-related genes for diagnosis and immune status in MS were investigated.

Methods

Gene Expression Omnibus (GEO) databases were utilized to analyze RNA-seq data for GM lesions in MS. Differentially expressed genes (DEGs) were identified. Weighted gene co-expression network analysis (WGCNA), least absolute shrinkage and selection operator (LASSO) algorithm and protein-protein interaction (PPI) network were used to screen related gene modules and candidate genes. The abundance of immune cell infiltration was analyzed by the CIBERSORT algorithm. Candidate genes with strong correlation with immune cell types were determined to be hub genes. A diagnosis model of nomogram was constructed based on the hub genes. Gene set enrichment analysis (GSEA) was performed to identify the biological functions of hub genes. Finally, an MS mouse model was induced to verify the expression levels of immune hub genes.

Results

Nine genes were identified by WGCNA, LASSO regression and PPI network. The infiltration of immune cells was significantly different between the MS and control groups. Four genes were identified as GM lesion-related hub genes. A reliable prediction model was established by nomogram and verified by calibration, decision curve analysis and receiver operating characteristic curves. GSEA indicated that the hub genes were mainly enriched in cell adhesion molecules, cytokine-cytokine receptor interaction and the JAK-STAT signaling pathway, etc.

Conclusions

TLR9, CCL5, CXCL8 and PDGFRB were identified as potential biomarkers for GM injury in MS. The effectively predicted diagnosis model will provide guidance for therapeutic intervention of MS.

Identification of a potential structure-based GPCR drug for interstitial cystitis/bladder pain syndrome: in silico protein structure analysis and molecular docking

INTRODUCTION AND HYPOTHESIS

There is currently no effective treatment for interstitial cystitis / bladder pain syndrome (IC/BPS) and thus seriously reduces the quality of life of patients. The purpose of this study is to analyze the structure and function of G protein coupled receptors related to IC/BPS by integrating bioinformatics and provide basis for the development of new drugs for IC/BPS.

METHODS

We used ProtParam and DNAMAN to analyze the physical and chemical properties of GPR18 and GPR183 proteins. The secondary and tertiary structure, conservative domain, phosphorylation site of both proteins were predicted by ProtScale, PredictProtein, SWISS-MODEL and GPS5.0 respectively. Multiple sequence alignment of the proteins were carried out by DNAMAN and the phylogenetic tree was constructed by MEGA. Further, the molecular docking verification of cannabidiol and both proteins were carried out by using AutoDock Vin.

RESULTS

GPR18 and GPR183 proteins were composed of 331 and 361 amino acids respectively. α-helix is the highest in the secondary structure of the two proteins. Both proteins contain seven transmembrane domains specific to G protein coupled receptors. And homology analysis showed that the two proteins had high homology. In terms of molecular docking, cannabidiol, a non psychoactive component extracted from the cannabis, can form effective molecular binding with GPR18 and GPR183 proteins.

CONCLUSIONS

We identified the structures of GPR18 and GPR183 proteins and their highly homologous evolutionary properties. Furthermore, both proteins can form effective binding with cannabidiol which provides new insights for the development of IC/BPS drugs by targeting G protein coupled receptors.

The immunological function of CXCR2 in the liver during sepsis

Background

The chemokine receptor CXCR2 and its ligands, especially CXCL8, are crucial mediators for the progression of liver inflammation and liver failure in sepsis. Neutrophils have the highest CXCR2 expression in mice and humans, and their activation via CXCL8 facilitates their migration to the inflamed liver for the clearance of the pathogens and, in turn, the inflammation.

Main body

In sepsis, the inflammatory insult causes extensive neutrophil migration to the liver that overwhelms the immune response. To compensate for the strong receptor activation, CXCR2 desensitizes, incapacitating the immune cells to efficiently clear pathogens, causing further life-threatening liver damage and uncontrolled pathogen spread.

Conclusion

CXCR2 function during infection strongly depends on the expressing cell type. It signals pro- and anti-inflammatory effects that may prompt novel cell-type-specific CXCR2-directed therapeutics.

The DARC Side of Inflamm-Aging: Duffy Antigen Receptor for Chemokines (DARC/ACKR1) as a Potential Biomarker of Aging, Immunosenescence, and Breast Oncogenesis among High-Risk Subpopulations

The proclivity of certain pre-malignant and pre-invasive breast lesions to progress while others do not continues to perplex clinicians. Clinicians remain at a crossroads with effectively managing the high-risk patient subpopulation owing to the paucity of biomarkers that can adequately risk-stratify and inform clinical decisions that circumvent unnecessary administration of cytotoxic and invasive treatments. The immune system mounts the most important line of defense against tumorigenesis and progression. Unfortunately, this defense declines or "ages" over time-a phenomenon known as immunosenescence. This results in "inflamm-aging" or the excessive infiltration of pro-inflammatory chemokines, which alters the leukocyte composition of the tissue microenvironment, and concomitant immunoediting of these leukocytes to diminish their antitumor immune functions. Collectively, these effects can foster the sequelae of neoplastic transformation and progression. The erythrocyte cell antigen, Duffy antigen receptor for chemokines(DARC/ACKR1), binds and internalizes chemokines to maintain homeostatic levels and modulate leukocyte trafficking. A negative DARC status is highly prevalent among subpopulations of West African genetic ancestry, who are at higher risk of developing breast cancer and disease progression at a younger age. However, the role of DARC in accelerated inflamm-aging and malignant transformation remains underexplored. Herein, we review compelling evidence suggesting that DARC may be protective against inflamm-aging and, therefore, reduce the risk of a high-risk lesion progressing to malignancy. We also discuss evidence supporting that immunotherapeutic intervention-based on DARC status-among high-risk subpopulations may evade malignant transformation and progression. A closer look into this unique role of DARC could glean deeper insight into the immune response profile of individual high-risk patients and their predisposition to progress as well as guide the administration of more "cyto-friendly" immunotherapeutic intervention to potentially "turn back the clock" on inflamm-aging-mediated oncogenesis and progression.

Anti-chemokine antibodies after SARS-CoV-2 infection correlate with favorable disease course

Infection by SARS-CoV-2 leads to diverse symptoms, which can persist for months. While antiviral antibodies are protective, those targeting interferons and other immune factors are associated with adverse COVID-19 outcomes. Instead, we discovered that antibodies against specific chemokines are omnipresent after COVID-19, associated with favorable disease, and predictive of lack of long COVID symptoms at one year post infection. Anti-chemokine antibodies are present also in HIV-1 infection and autoimmune disorders, but they target different chemokines than those in COVID-19. Monoclonal antibodies derived from COVID- 19 convalescents that bind to the chemokine N-loop impair cell migration. Given the role of chemokines in orchestrating immune cell trafficking, naturally arising anti-chemokine antibodies associated with favorable COVID-19 may be beneficial by modulating the inflammatory response and thus bear therapeutic potential.

One-Sentence Summary

Naturally arising anti-chemokine antibodies associate with favorable COVID-19 and predict lack of long COVID.

A Systems Biology Approach on the Regulatory Footprint of Human Endogenous Retroviruses (HERVs)

Human endogenous retroviruses (HERVs) are a family of endogenous retroviruses that comprise the ~8.93% of the human genome sequence, with a high proportion being human specific. The recent expansion of repeated HERV sequences has offered a framework for genetic and epigenetic innovation. In the current report, a systematic approach is implemented to catalogue regulatory elements within HERVs, as a roadmap to potential functions of HERV sequences in gene networks. ENCODE Project has offered a wealth of epigenetic data based on omics technologies. I analyzed the presence of HERV sequences on consensus cis-regulatory elements (cCREs) from ENCODE data. On the one side, HERVs are in 1 out of 9 cCREs (>100.000 cCREs in total), dispersed within the genome and present in cis-regulatory regions of ~81% of human genes, as calculated following gene enrichment analysis. On the other side, promoter-associated HERV cCREs are present adjacent to (in a 200 bp window) the transcription start sites of 256 human genes. Regulatory network production, followed by centrality analysis led to the discovery of 90 core genes containing HERV-associated promoters. Pathway analysis on the core network genes and their immediate neighbors revealed a regulatory footprint that, among others, is associated with inflammation, chemokine signaling and response to viral infection. Collectively, these results support the concept that the expansion of regulatory sequences derived from HERVs is critical for epigenetic innovation that may have wired together genes into novel transcriptional networks with critical roles in cellular physiology and pathology.

Multifaceted role of chemokines in solid tumors: From biology to therapy

Chemokines are small secretory chemotactic cytokines that control the directed migration of immune cells. Chemokines are involved in both anti-and pro-tumorigenic immune responses. Accumulating evidence suggests that the balance between these responses is influenced by several factors such as the stage of tumorigenesis, immune cell activation, recruitment of immune activating or immunosuppressive cells in the tumor microenvironment (TME), and chemokine receptor expression on effector and regulatory target cells. Cancer cells engage in a complex network with their TME components via several factors including growth factors, cytokines and chemokines that are critical for the growth of primary tumor and metastasis. However, chemokines show a multifaceted role in tumor progression including maintenance of stem-like properties, tumor cell proliferation/survival/senescence, angiogenesis, and metastasis. The heterogeneity of solid tumors in primary and metastatic cancers presents a challenge to the development of successful cancer therapy. Despite extensive research on how solid tumors escape immune cell-mediated anti-tumor response, finding an effective therapy for metastatic cancer still remains a challenge. This review discusses the multifarious roles of chemokines in solid tumors including various chemokine signaling pathways such as CXCL8-CXCR1/2, CXCL9, 10, 11-CXCR3, CXCR4-CXCL12, CCL(X)-CCR(X) in primary and metastatic cancers. We further discuss the novel therapeutic approaches that have been developed by major breakthroughs in chemokine research to treat cancer patients by the strategic blockade/activation of these signaling axes alone or in combination with immunotherapies.

Chemokine Homeostasis in Healthy Volunteers and during Pancreatic and Colorectal Tumor Growth in Murine Models

Chemokines are involved in the humoral regulation of body homeostasis. Changes in the blood level of chemokines were found in cancer, atherosclerosis, diabetes, and other systemic diseases. It is essential to distinguish the effects of co-morbid pathologies and cancer on the level of chemokines in the blood. We aimed to analyze, by multiplex cytometry, the levels of chemokines in the blood of healthy young volunteers as well as of intact mice and mice with CT26 colon and Pan02 pancreatic tumors. Two types of chemokines were identified both in human and murine plasmas: homeostatic ones, which were found in high concentrations (>100 pg/mL), and inducible ones, which can be undetectable or determined at very low levels (0−100 pg/mL). There was a high variability in the chemokine levels, both in healthy humans and mice. To analyze chemokine levels during tumor growth, C57BL/6 and BALB/c were inoculated with Pan02 or CT26 tumor cells, accordingly. The tumors significantly differed in the growth and the mortality of mice. However, the blood chemokine levels did not change in tumor-bearing mice until the very late stages. Taken collectively, blood chemokine level is highly variable and reflects in situ homeostasis. Care should be taken when considering chemokines as prognostic parameters or therapeutic targets in cancer.

Serum CC Chemokines as Potential Biomarkers for the Diagnosis of Major Depressive Disorder

Objective

Evidence indicates a potential role of chemokines in depression-like behavior and depression-related pathophysiological processes. In the present study, we examined the serum levels of multiple chemokines, focusing on CC chemokines, in patients with major depressive disorder (MDD), with the aim to discover and identify serum chemokines-based biomarkers for MDD diagnosis.

Methods

Participants included 24 patients with MDD and 24 healthy controls. The 24-item Hamilton Depression Rating Scale (HAMD-24) was administered to assess the disease severity of patients with MDD. A total of 9 serum CC chemokines including MCP-1 (CCL-2), MIP-1α (CCL-3), MIP-1β (CCL-4), eotaxin-1 (CCL-11), MCP-4 (CCL-13), TARC (CCL-17), MIP-3α (CCL-20), MDC (CCL-22), and Eotaxin-3 (CCL-26) were measured using electrochemiluminescence immunoassays. The levels of serum CC chemokines between MDD group and control group were compared, and diagnostic values of different CC chemokines were evaluated using the receiver operating characteristic (ROC) curve method for discriminating MDD patients from healthy controls. Correlations between the levels of serum CC chemokines and depression severity (HAMD-24 scores) were evaluated using Pearson's correlation test.

Results

Patients with MDD had higher levels of serum MIP-1α and MIP-1β and lower levels of serum MCP-1, MCP-4, TARC, MDC, and Eotaxin-3 compared to controls (all P < 0.05). Moreover, ROC curve analysis showed that the Area Under Curve (AUC) values of MIP-1α, MCP-4, TARC, and Eotaxin-3 were > 0.7 in discriminating patients with MDD from healthy controls. Furthermore, no significant relationship was found between the levels of serum CC chemokines and HAMD-24 scores in MDD group.

Conclusion

These results suggested that circulating CC chemokines may hold promise in the discovery of biomarkers for diagnosing MDD.

Biodetection Techniques for Quantification of Chemokines

Chemokines are a class of cytokine whose special properties, together with their involvement and relevant role in various diseases, make them a restricted group of biomarkers suitable for diagnosis and monitoring. Despite their importance, biodetection techniques dedicated to the selective determination of one or more chemokines are very scarce. For some years now, the critical diagnosis of inflammatory diseases by detecting both cytokine and chemokine biomarkers, has had a strong impact on the development of multiple detection platforms. However, it would be desirable to implement methodologies with a higher degree of selectivity for chemokines, in order to provide more precise information. In addition, better development of biosensor technology applied to this specific field would make it possible to address the main challenges of detection methods for several diseases with a high incidence in the population, avoiding high costs and low sensitivity. Taking this into account, this review aims to present the state of the art of chemokine biodetection techniques and emphasize the role of these systems in the prevention, monitoring and treatment of various diseases associated with chemokines as a starting point for future developments that are also analyzed throughout the article.