An important role of the SDF-1/CXCR4 axis in chronic skin inflammation

Investigating shared diagnostic genes and mechanisms between metabolic syndrome and dry eye disease via integrated bioinformatics analysis and in vivo validation

Recent research has established a bidirectional connection between metabolic syndrome (MetS) and dry eye disease (DED); however, the underlying mechanisms driving their co-occurrence remain poorly understood. This study employed bioinformatics and in vivo validation to investigate the shared diagnostic genes and underlying mechanisms linking MetS and DED. Differential expression analysis using Limma and weighted gene co-expression network analysis (WGCNA) identified 247 shared driver genes from MetS and DED cohorts. Functional enrichment analysis indicated that these genes are associated with immune regulation and inflammatory responses. Key diagnostic genes (Ccl5, Cxcr4, Ccl4, Spp1) were identified via PPI network analysis and validated using a receiver operating characteristic (ROC) curve. The MetS-DED mouse model further demonstrated CXCR4 overexpression in corneal epithelium and liver. These findings elucidate overlapping biomarkers and pathogenic pathways between MetS and DED, providing critical insights for advancing their diagnosis and therapeutic strategies.

ACKR3 in Skin Homeostasis, an Overlooked Player in the CXCR4/CXCL12 Axis

CXCL12 and its receptor CXCR4 emerge as critical regulators within the intricate network of processes ensuring skin homeostasis. In this review, we discuss their spatial distribution and function in steady-state skin; delve into their role in acute wound healing, with emphasis on fibrotic and regenerative responses; and explore their relevance in skin responses to commensals and pathogens. Given the lack of knowledge surrounding ACKR3, the atypical receptor of CXCL12, we speculate whether and how it might be involved in the processes mentioned earlier. Is ACKR3 the (a)typical friend who enjoys missing the party, or do we need to take a closer look?

Unveiling the molecular mechanisms of Haitang-Xiaoyin Mixture in psoriasis treatment based on bioinformatics, network pharmacology, machine learning, and molecular docking verification

OBJECTIVE

Psoriasis is a common clinical skin inflammatory disease. Haitang-Xiaoyin Mixture (HXM) represents a traditional Chinese medicine formulation utilized clinically for the management of psoriasis, which can reduce the psoriasis area and severity index (PASI) score, IL-23 and IL-23 levels in patients with psoriasis. However, the main active components and specific targets of HXM in the treatment of psoriasis and the relevant mechanisms of action are not clear. Therefore, in the study we aimed to elucidate the mechanistic basis of HXM's therapeutic action in psoriasis treatment through the application of bioinformatics, network pharmacology, machine learning and molecular docking methodologies.

METHODS

The psoriasis-related genes were obtained from the Gene Expression Omnibus (GEO) dataset, which psoriasis-associated disease genes were identified utilizing the GeneCard and DisGeNEt databases. The active ingredients of HXM were retrieved from HERB and TCMSP databases. Protein-Protein Interactions (PPI), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted to identify potential targets and signaling pathways. Psoriasis key targets were determined using LASSO, SVM-RFE, and Boruta algorithms, followed by Receiver Operating Characteristic (ROC) analysis. Key targets were GESA enriched and analyzed for transcription factors and immune cell infiltration. Finally molecular docking and molecular dynamics simulations were performed to validate the binding of active compounds to core targets, elucidating their mechanism of action.

RESULTS

A total of 233 psoriasis-related targets and 290 drug targets were identified. After data set crossover, 37 pharmacodynamic targets were obtained. PPI network topology analysis revealed 12 core targets. GO and KEGG enrichment analysis suggested that HXM may regulate angiogenesis, chemokine receptor binding process, as well as IL-17 and TNF related signaling pathways. Machine algorithm screening identified two psoriasis characteristic genes: CXCL2 and CXCR4. Immune infiltration results demonstrated a significant positive correlation between the characteristic genes and M1 macrophages, along with identification of the top 20 transcription factors involved. Quercetin and triptolide were recognized as potential core components of HXM for treating psoriasis based on their molecular docking and molecular dynamics simulation results confirming strong binding abilities with CXCL2 and CXCR4 respectively.

CONCLUSION

This study elucidates the active constituents, potential targets, and underlying pathways involved in the therapeutic effects of HXM for psoriasis. Specifically, CXCL2 and CXCR4 are identified as key targets, with quercetin and triptolide representing crucial compounds exerting their effects on these targets.

Development of Machine Learning Models for Predicting Radiation Dermatitis in Breast Cancer Patients Using Clinical Risk Factors, Patient-Reported Outcomes, and Serum Cytokine Biomarkers

BACKGROUND

Radiation dermatitis (RD) is a significant side effect of radiotherapy experienced by breast cancer patients. Severe symptoms include desquamation or ulceration of irradiated skin, which impacts quality of life and increases healthcare costs. Early identification of patients at risk for severe RD can facilitate preventive management and reduce severe symptoms. This study evaluated the utility of subjective and objective factors, such as patient-reported outcomes (PROs) and serum cytokines, for predicting RD in breast cancer patients. The performance of machine learning (ML) and logistic regression-based models were compared.

PATIENTS AND METHODS

Data from 147 breast cancer patients who underwent radiotherapy was analyzed to develop prognostic models. ML algorithms, including neural networks, random forest, XGBoost, and logistic regression, were employed to predict clinically significant Grade 2+ RD. Clinical factors, PROs, and cytokine biomarkers were incorporated into the risk models. Model performance was evaluated using nested cross-validation with separate loops for hyperparameter tuning and calculating performance metrics.

RESULTS

Feature selection identified 18 predictors of Grade 2+ RD including smoking, radiotherapy boost, reduced motivation, and the cytokines interleukin-4, interleukin-17, interleukin-1RA, interferon-gamma, and stromal cell-derived factor-1a. Incorporating these predictors, the XGBoost model achieved the highest performance with an area under the curve (AUC) of 0.780 (95% CI: 0.701-0.854). This was not significantly improved over the logistic regression model, which demonstrated an AUC of 0.714 (95% CI: 0.629-0.798).

CONCLUSION

Clinical risk factors, PROs, and serum cytokine levels provide complementary prognostic information for predicting severe RD in breast cancer patients undergoing radiotherapy. ML and logistic regression models demonstrated comparable performance for predicting clinically significant RD with AUC>0.70.

Humanized CXCL12 antibody delays onset and modulates immune response in alopecia areata mice: insights from single-cell RNA sequencing

It has been demonstrated that CXCL12 inhibits hair growth via CXCR4, and its neutralizing antibody (Ab) increases hair growth in alopecia areata (AA). However, the molecular mechanisms have not been fully elucidated. In the present study, we further prepared humanized CXCL12 Ab for AA treatment and investigated underlying molecular mechanisms using single-cell RNA sequencing. Subcutaneous injection of humanized CXCL12 Ab significantly delayed AA onset in mice, and dorsal skin was analyzed. T cells and dendritic cells/macrophages were increased in the AA model, but decreased after CXCL12 Ab treatment. Pseudobulk RNA sequencing identified 153 differentially expressed genes that were upregulated in AA model and downregulated after Ab treatment. Gene ontology analysis revealed that immune cell chemotaxis and cellular response to type II interferon were upregulated in AA model but downregulated after Ab treatment. We further identified key immune cell-related genes such as Ifng, Cd8a, Ccr5, Ccl4, Ccl5, and Il21r, which were colocalized with Cxcr4 in T cells and regulated by CXCL12 Ab treatment. Notably, CD8+ T cells were significantly increased and activated via Jak/Stat pathway in the AA model but inactivated after CXCL12 Ab treatment. Collectively, these results indicate that humanized CXCL12 Ab is promising for AA treatment via immune modulatory effects.

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.

CD4+CCR5+ T cells and CCL3+ mast cells are increased in the skin of patients with chronic spontaneous urticaria

Background

The proximity of activated T cells and mast cells in the lesional skin of patients with chronic spontaneous urticaria (CSU) is held to contribute to the development of wheals and angioedema. In a previous study, we demonstrated that increased IL-17 expression in T cells and mast cells in skin lesions of patients with CSU is associated with T/mast cell proximity, but the mechanisms that drive T cell/mast cell co-localization remain unknown.

Objectives

To assess if chemokines expressed in lesional CSU skin contribute to T cell/mast cell proximity.

Patients and methods

Biopsies from lesional CSU skin were compared to biopsies from healthy skin for expression of CCR5 and its ligand CCL3 by CD4+ T cells and mast cells, respectively.

Results

Numbers of CCR5-positive CD4+ T cells in lesional CSU skin were significantly increased as compared to healthy normal skin (p < 0.0001). The number of mast cells expressing CCL3 (ligand for CCR5) in CSU skin was also increased (p < 0.0002) and significant association with T-cell close proximity (p < 0.0001) is noticed.

Conclusions

The close proximity of T cells and mast cells in the skin of severe CSU may be driven, at least in part by increased CCR5 and CCL3 expression. Therapies that target CCL3 interaction with CCR5 should be assessed for their effects in CSU.

Silencing of transient receptor potential canonical channel 4 inhibits endothelial progenitor cell angiogenesis by suppressing VEGF and SDF-1

OBJECTIVES

Endothelial progenitor cells (EPCs) play a crucial role in acquired angiogenesis and endothelial injury repair. Transient receptor potential canonical channel 4 (TRPC4), a key component of store-operated calcium channels, is essential for EPC function. While the role of TRPCs has been clarified in vascular diseases, the relationship between TRPC4 and EPC function, along with the underlying molecular mechanisms, remains unclear and requires further elucidation.

METHODS

EPCs were isolated from canine bone marrow and identified by morphology and flow cytometry. TRPC4 was transfected into EPCs using lentivirus or negative control, and its expression was assessed using real-time polymerase chain reaction (RT-PCR). Proliferation, migration, and tube formation were evaluated using Cell Counting Kit-8 (CCK-8), Transwell, and Matrigel assays, respectively. Levels of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1) were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

TRPC4 mRNA expression was significantly reduced in TRPC4-short hairpin RNA (shRNA) transfected EPCs compared to the normal control (NC)-shRNA groups. Migration and tube formation were significantly decreased after TRPC4 silencing, while proliferation showed no difference. Additionally, levels of SDF-1 and VEGF in EPCs were markedly reduced following TRPC4 silencing.

CONCLUSION

TRPC4 plays a crucial role in regulating angiogenesis in EPCs. Silencing of TRPC4 can lead to decreased angiogenesis by inhibiting VEGF and SDF-1 expression, suggesting that TRPC4 knockdown might be a novel therapeutic strategy for vascular diseases.

The Anti-Inflammatory Effect of SDF-1 Derived Peptide on Porphyromonas gingivalis Infection via Regulation of NLRP3 and AIM2 Inflammasome

(1) Background: Peptides are appealing as pharmacological materials because they are easily produced, safe, and tolerable. Despite increasing gum-care awareness, periodontitis is still prevalent and is influenced by factors like high sugar consumption, smoking, and aging. Porphyromonas gingivalis is considered a major etiologic agent of periodontitis and activates the NLR family pyrin domain containing 3 (NLRP3) but is absent in melanoma 2 (AIM2) inflammasomes, resulting in pro-inflammatory cytokine release. (2) Methods: We examined the anti-inflammatory effects of 18 peptides derived from human stromal cell-derived factor-1 (SDF-1) on THP-1 macrophages. Inflammation was induced by P. gingivalis, and the anti-inflammatory effects were analyzed using molecular biological techniques. In a mouse periodontitis model, alveolar bone resorption was assessed using micro-CT. (3) Results: Of the 18 SDF-1-derived peptides, S10 notably reduced IL-1β and TNF-α secretion. S10 also diminished the P. gingivalis-induced expression of NLRP3, AIM2, ASC (apoptosis-associated speck-like protein), caspase-1, and IL-1β. Furthermore, S10 attenuated the enhanced TLR (toll-like receptor) signaling pathway and decreased the phosphorylation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs). In addition, S10 mitigated alveolar bone loss in our P. gingivalis-induced mouse model of periodontitis. (4) Conclusions: S10 suppressed TLR/NF-κB/NLRP3 inflammasome signaling and the AIM2 inflammasome in our P. gingivalis-induced murine periodontitis model, which suggests that it has potential use as a therapeutic treatment for periodontitis.

CXCR4/CXCL12 axis: "old" pathway as "novel" target for anti-inflammatory drug discovery

Inflammation is the body's defense response to exogenous or endogenous stimuli, involving complex regulatory mechanisms. Discovering anti-inflammatory drugs with both effectiveness and long-term use safety is still the direction of researchers' efforts. The inflammatory pathway was initially identified to be involved in tumor metastasis and HIV infection. However, research in recent years has proved that the CXC chemokine receptor type 4 (CXCR4)/CXC motif chemokine ligand 12 (CXCL12) axis plays a critical role in the upstream of the inflammatory pathway due to its chemotaxis to inflammatory cells. Blocking the chemotaxis of inflammatory cells by CXCL12 at the inflammatory site may block and alleviate the inflammatory response. Therefore, developing CXCR4 antagonists has become a novel strategy for anti-inflammatory therapy. This review aimed to systematically summarize and analyze the mechanisms of action of the CXCR4/CXCL12 axis in more than 20 inflammatory diseases, highlighting its crucial role in inflammation. Additionally, the anti-inflammatory activities of CXCR4 antagonists were discussed. The findings might help generate new perspectives for developing anti-inflammatory drugs targeting the CXCR4/CXCL12 axis.

Comparative analysis of whole plant, flower and root extracts of Chamomilla recutita L. and characteristic pure compounds reveals differential anti-inflammatory effects on human T cells

Introduction

Chronic inflammation is a hallmark of chronic wounds and inflammatory skin diseases. Due to a hyperactive and prolonged inflammation triggered by proinflammatory immune cells, transitioning to the repair and healing phase is halted. T cells may exacerbate the proinflammatory milieu by secreting proinflammatory cytokines. Chamomilla recutita L. (chamomile) has been suggested for use in several inflammatory diseases, implying a capability to modulate T cells. Here, we have characterized and compared the effects of differently prepared chamomile extracts and characteristic pure compounds on the T cell redox milieu as well as on the migration, activation, proliferation, and cytokine production of primary human T cells.

Methods

Phytochemical analysis of the extracts was carried out by LC-MS/MS. Primary human T cells from peripheral blood (PBTs) were pretreated with aqueous or hydroethanolic chamomile extracts or pure compounds. Subsequently, the effects on intracellular ROS levels, SDF-1α induced T cell migration, T cell activation, proliferation, and cytokine production after TCR/CD3 and CD28 costimulation were determined. Gene expression profiling was performed using nCounter analysis, followed by ingenuity pathway analysis, and validation at protein levels.

Results

The tested chamomile extracts and pure compounds differentially affected intracellular ROS levels, migration, and activation of T cells. Three out of five differently prepared extracts and two out of three pure compounds diminished T cell proliferation. In line with these findings, LC-MS/MS analysis revealed high heterogeneity of phytochemicals among the different extracts. nCounter based gene expression profiling identified several genes related to T cell functions associated with activation and differentiation to be downregulated. Most prominently, apigenin significantly reduced granzyme B induction and cytotoxic T cell activity.

Conclusion

Our results demonstrate an anti-inflammatory effect of chamomile- derived products on primary human T cells. These findings provide molecular explanations for the observed anti-inflammatory action of chamomile and imply a broader use of chamomile extracts in T cell driven chronic inflammatory diseases such as chronic wounds and inflammatory skin diseases. Importantly, the mode of extract preparation needs to be considered as the resulting different phytochemicals can result in differential effects on T cells.

The Immunology of Psoriasis-Current Concepts in Pathogenesis

Psoriasis is one of the most common inflammatory skin diseases with a chronic, relapsing-remitting course. The last decades of intense research uncovered a pathological network of interactions between immune cells and other types of cells in the pathogenesis of psoriasis. Emerging evidence indicates that dendritic cells, TH17 cells, and keratinocytes constitute a pathogenic triad in psoriasis. Dendritic cells produce TNF-α and IL-23 to promote T cell differentiation toward TH17 cells that produce key psoriatic cytokines IL-17, IFN-γ, and IL-22. Their activity results in skin inflammation and activation and hyperproliferation of keratinocytes. In addition, other cells and signaling pathways are implicated in the pathogenesis of psoriasis, including TH9 cells, TH22 cells, CD8+ cytotoxic cells, neutrophils, γδ T cells, and cytokines and chemokines secreted by them. New insights from high-throughput analysis of lesional skin identified novel signaling pathways and cell populations involved in the pathogenesis. These studies not only expanded our knowledge about the mechanisms of immune response and the pathogenesis of psoriasis but also resulted in a revolution in the clinical management of patients with psoriasis. Thus, understanding the mechanisms of immune response in psoriatic inflammation is crucial for further studies, the development of novel therapeutic strategies, and the clinical management of psoriasis patients. The aim of the review was to comprehensively present the dysregulation of immune response in psoriasis with an emphasis on recent findings. Here, we described the role of immune cells, including T cells, B cells, dendritic cells, neutrophils, monocytes, mast cells, and innate lymphoid cells (ILCs), as well as non-immune cells, including keratinocytes, fibroblasts, endothelial cells, and platelets in the initiation, development, and progression of psoriasis.

Resistin - A Plausible Therapeutic Target in the Pathogenesis of Psoriasis

Resistin, a cytokine hormone predominantly secreted by adipose tissue, is elevated in various metabolic disorders such as obesity, type 2 diabetes, and cardiovascular disease. In addition to its involvement in metabolic regulation, resistin has been implicated in the pathogenesis of psoriasis, a chronic inflammatory skin disorder. Numerous studies have reported increased resistin levels in psoriatic skin lesions, suggesting a possible association between resistin and psoriasis. Recent studies have suggested the potential involvement of resistin in the development and progression of certain cancers. Resistin is overexpressed in breast, colorectal, and gastric cancers. This suggests that it may play a role in the development of these cancers, possibly by inducing inflammation and cell growth. The link between resistin and cancer raises the possibility of shared underlying mechanisms driving the pathogenesis of psoriasis. Chronic inflammation, one such mechanism, is a hallmark of psoriasis and cancer. Further research is needed to fully understand the relationship between resistin and psoriasis. Identifying potential therapeutic targets is crucial for effective management of psoriasis. By doing so, we may be able to develop more effective treatment options for individuals living with psoriasis and ultimately improve their quality of life. Ultimately, a more comprehensive understanding of the mechanisms underlying the impact of resistin on psoriasis is essential for advancing our knowledge and finding new ways to treat and manage this challenging condition.

CXCL12 Neutralizing Antibody Promotes Hair Growth in Androgenic Alopecia and Alopecia Areata

We had previously investigated the expression and functional role of C-X-C Motif Chemokine Ligand 12 (CXCL12) during the hair cycle progression. CXCL12 was highly expressed in stromal cells such as dermal fibroblasts (DFs) and inhibition of CXCL12 increased hair growth. Therefore, we further investigated whether a CXCL12 neutralizing antibody (αCXCL12) is effective for androgenic alopecia (AGA) and alopecia areata (AA) and studied the underlying molecular mechanism for treating these diseases. In the AGA model, CXCL12 is highly expressed in DFs. Subcutaneous (s.c.) injection of αCXCL12 significantly induced hair growth in AGA mice, and treatment with αCXCL12 attenuated the androgen-induced hair damage in hair organ culture. Androgens increased the secretion of CXCL12 from DFs through the androgen receptor (AR). Secreted CXCL12 from DFs increased the expression of the AR and C-X-C Motif Chemokine Receptor 4 (CXCR4) in dermal papilla cells (DPCs), which induced hair loss in AGA. Likewise, CXCL12 expression is increased in AA mice, while s.c. injection of αCXCL12 significantly inhibited hair loss in AA mice and reduced the number of CD8+, MHC-I+, and MHC-II+ cells in the skin. In addition, injection of αCXCL12 also prevented the onset of AA and reduced the number of CD8+ cells. Interferon-γ (IFNγ) treatment increased the secretion of CXCL12 from DFs through the signal transducer and activator of transcription 3 (STAT3) pathway, and αCXCL12 treatment protected the hair follicle from IFNγ in hair organ culture. Collectively, these results indicate that CXCL12 is involved in the progression of AGA and AA and antibody therapy for CXCL12 is promising for hair loss treatment.

New insight into the role of fibroblasts in the epithelial immune microenvironment in the single-cell era

The skin is exposed to environmental challenges and contains heterogeneous cell populations such as epithelial cells, stromal cells, and skin-resident immune cells. As the most abundant type of stromal cells, fibroblasts have been historically considered silent observers in the immune responses of the cutaneous epithelial immune microenvironment (EIME), with little research conducted on their heterogeneity and immune-related functions. Single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST) have overcome the limitations of bulk RNA sequencing and help recognize the functional and spatial heterogeneity of fibroblasts, as well as their crosstalk with other types of cells in the cutaneous EIME. Recently, emerging single-cell sequencing data have demonstrated that fibroblasts notably participate in the immune responses of the EIME and impact the initiation and progression of inflammatory skin diseases. Here, we summarize the latest advances in the role of fibroblasts in the cutaneous EIME of inflammatory skin diseases and discuss the distinct functions and molecular mechanisms of activated fibroblasts in fibrotic skin diseases and non-fibrotic inflammatory skin diseases. This review help unveil the multiple roles of fibroblasts in the cutaneous EIME and offer new promising therapeutic strategies for the management of inflammatory skin diseases by targeting fibroblasts or the fibroblast-centered EIME.

Bioinformatics and Systems Biology Approach to Identify the Pathogenetic Link Between Psoriasis and Cardiovascular Disease

Objective

This study aimed to identify hub genes and common pathways shared between psoriasis and cardiovascular disease (CVD) using bioinformatics analysis and predict the transcription factors (TFs) of hub genes.

Methods

GSE133555 data from the Gene Expression Omnibus (GEO) database were used to identify differentially expressed genes (DEGs) between involved and uninvolved skin lesions in psoriasis, employing the limma package in R. Additionally, CVD-related genes were obtained from the GeneCards database. The intersection of DEGs and CVD-related genes yielded CVD-DEGs. Gene Ontology and signaling pathway analyses were performed using the clusterProfiler package in R. Hub genes were identified by intersecting six algorithms in the CytoHubba plugin of Cytoscape. To identify potential biomarkers, the GSE14905 dataset was subjected to receiver operating characteristic analysis, resulting in the identification of eight central hub genes. Finally, the NetworkAnalyst web tool was used to identify the TFs of the eight hub genes.

Results

We identified 92 significant DEGs out of 1825 CVD-related genes in psoriasis obtained from the GSE13355 and GeneCard data. Functional enrichment analysis revealed the involvement of these genes in various signaling pathways, including the interleukin-17 signaling, tumor necrosis factor signaling, lipid and atherosclerosis, chemokine signaling, and cytokine signaling pathways in the immune system. The eight hub genes identified included interleukin-1 beta, C-X-C motif chemokine ligand 8, signal transducer and activator of transcription 3, C-C motif chemokine ligand 2, arginase 1, C-X-C motif chemokine receptor 4, cyclin D1, and matrix metallopeptidase 9, with forkhead box C1 also identified as an associated TF of these genes. These hub genes and TF may act as key regulators in the context of CVD.

Conclusion

This study identified several hub genes and signaling pathways associated with both CVD and psoriasis. These findings lay the groundwork for potential therapeutic interventions for patients with psoriasis affected by CVD.

Design principles of microparticle size and immunomodulatory factor formulation dictate antigen-specific amelioration of multiple sclerosis in a mouse model

Antigen-specific therapies allow for modulation of the immune system in a disease relevant context without systemic immune suppression. These therapies are especially valuable in autoimmune diseases such as multiple sclerosis (MS), where autoreactive T cells destroy myelin sheath. This work shows that an antigen-specific dual-sized microparticle (dMP) system can effectively halt and reverse disease progression in a mouse model of MS. Current MS treatments leave patients immunocompromised, but the dMP formulation spares the immune system as mice can successfully clear a Listeria Monocytogenes infection. Furthermore, we highlight design principles for particle based immunotherapies including the importance of delivering factors specific for immune cell recruitment (GM-CSF or SDF-1), differentiation (GM-CSF or FLT3L) and suppression (TGF-β or VD3) in conjunction with disease relevant antigen, as the entire formulation is required for maximum efficacy. Lastly, the dMP scheme relies on formulating phagocytosable and non-phagocytosable MP sizes to direct payload to target either cell surface receptors or intracellular targets, as the reverse sized dMP formulation failed to reverse paralysis. We also challenge the design principles of the dMP system showing that the size of the MPs impact efficacy and that GM-CSF plays two distinct roles and that both of these must be replaced to match the primary effect of the dMP system. Overall, this work shows the versatile nature of the dMP system and expands the knowledge in particle science by emphasizing design tenets to guide the next generation of particle based immunotherapies.

Mendelian Randomization Studies in Psoriasis and Psoriatic Arthritis: A Systematic Review

Psoriasis (PSO) and psoriatic arthritis (PSA) are inflammatory diseases with complex genetic and environmental contributions. Although studies have identified environmental and clinical associations with PSO/PSA, causality is difficult to establish. Mendelian randomization (MR) employs the random assortment of genetic alleles at birth to evaluate the causal impact of exposures. We systematically reviewed 27 MR studies in PSO/PSA examining health behaviors, comorbidities, and biomarkers. Exposures, including smoking, obesity, cardiovascular disease, and Crohn's disease, were causal for PSO and PSA, whereas PSO was causally associated with several comorbidities. These findings provide insights that can guide preventive counseling and precision medicine.

Tissue adaptation and clonal segregation of human memory T cells in barrier sites

T lymphocytes migrate to barrier sites after exposure to pathogens, providing localized immunity and long-term protection. Here, we obtained blood and tissues from human organ donors to examine T cells across major barrier sites (skin, lung, jejunum), associated lymph nodes, lymphoid organs (spleen, bone marrow), and in circulation. By integrating single-cell protein and transcriptome profiling, we demonstrate that human barrier sites contain tissue-resident memory T (T_RM) cells that exhibit site-adapted profiles for residency, homing and function distinct from circulating memory T cells. Incorporating T cell receptor and transcriptome analysis, we show that circulating memory T cells are highly expanded, display extensive overlap between sites and exhibit effector and cytolytic functional profiles, while T_RM clones exhibit site-specific expansions and distinct functional capacities. Together, our findings indicate that circulating T cells are more disseminated and differentiated, while T_RM cells exhibit tissue-specific adaptation and clonal segregation, suggesting that strategies to promote barrier immunity require tissue targeting.

The Monocytic Cell Line THP-1 as a Validated and Robust Surrogate Model for Human Dendritic Cells

We have implemented an improved, cost-effective, and highly reproducible protocol for a simple and rapid differentiation of the human leukemia monocytic cell line THP-1 into surrogates for immature dendritic cells (iDCs) or mature dendritic cells (mDCs). The successful differentiation of THP-1 cells into iDCs was determined by high numbers of cells expressing the DC activation markers CD54 (88%) and CD86 (61%), and the absence of the maturation marker CD83. The THP-1-derived mDCs are characterized by high numbers of cells expressing CD54 (99%), CD86 (73%), and the phagocytosis marker CD11b (49%) and, in contrast to THP-1-derived iDCs, CD83 (35%) and the migration marker CXCR4 (70%). Treatment of iDCs with sensitizers, such as NiSO4 and DNCB, led to high expression of CD54 (97%/98%; GMFI, 3.0/3.2-fold induction) and CD86 (64%/96%; GMFI, 4.3/3.2-fold induction) compared to undifferentiated sensitizer-treated THP-1 (CD54, 98%/98%; CD86, 55%/96%). Thus, our iDCs are highly suitable for toxicological studies identifying potential sensitizing or inflammatory compounds. Furthermore, the expression of CD11b, CD83, and CXCR4 on our iDC and mDC surrogates could allow studies investigating the molecular mechanisms of dendritic cell maturation, phagocytosis, migration, and their use as therapeutic targets in various disorders, such as sensitization, inflammation, and cancer.

Targeting CXCL12/CXCR4 Signaling with AMD3100 Might Selectively Suppress CXCR4+ T-Cell Chemotaxis Leading to the Alleviation of Chronic Prostatitis

Background

Chronic nonbacterial prostatitis (CNP) has a high incidence, low cure rate, and unclear pathogenesis. Here, we aimed to systematically identify effective diagnostic and therapeutic targets for CNP.

Methods

Prostate tissues were obtained from established mouse models and negative controls and were used for mRNA array sequencing and immunohistochemistry (IHC) staining. Predominant pathways were identified based on pathway enrichment analysis and pharmaceutical experiments. We also investigated the functional role of CXCL12 on CP, a critical factor belonging to the predominant chemotaxis pathway, and employed IHC staining to explore the influence of the CXCL12/CXCR4 axis on the activation of the NF-κB, AKT, and STAT3 signaling pathways. Serum samples derived from both CNP cases and healthy controls were used to determine the secretion level of CXCL12.

Results

By employing mRNA array sequencing and immunohistochemistry, we found that CXCR4, CXCL12, CD44, and OFLM4 were highly expressed in the infiltrated inflammatory T cells of the prostate tissues generated from CNP mice, while they were rarely expressed on the epithelial cells. Based on the pathway enrichment results, we applied pathway inhibitors to suppress the activity of these classic pathways. We found that targeting the CXCL12/CXCR4 axis with its specific antagonist AMD3100 remarkably alleviated inflammatory infiltration of the prostate in CNP models. Similar results were obtained when we replaced AMD3100 with adenovirus-associated virus (AAV)-shCxcl12. To clarify the potential mechanisms of how the CXCL12/CXCR4 axis influences the pathogenesis of CNP, we tested the classical downstream pathways. The results suggested that p-Akt, p-STAT3, and p-NF-κB were more highly expressed on the inflammatory cells of the prostate derived from the CNP model and were partly suppressed after applying AMD3100 or delivering AAV-shCxcl12, indicating that the CXCL12/CXCR4 axis potentially functioned through AKT/NF-κB and STAT3 signaling to influence the pathogenesis of CNP.

Conclusion

Our study provides potential diagnostic biomarkers and therapeutic targets for CNP.

Cellular crosstalk of glomerular endothelial cells and podocytes in diabetic kidney disease

Diabetic kidney disease (DKD) is a serious microvascular complication of diabetes and is the leading cause of end-stage renal disease (ESRD). Persistent proteinuria is an important feature of DKD, which is caused by the destruction of the glomerular filtration barrier (GFB). Glomerular endothelial cells (GECs) and podocytes are important components of the GFB, and their damage can be observed in the early stages of DKD. Recently, studies have found that crosstalk between cells directly affects DKD progression, which has prospective research significance. However, the pathways involved are complex and largely unexplored. Here, we review the literature on cellular crosstalk of GECs and podocytes in the context of DKD, and highlight specific gaps in the field to propose future research directions. Elucidating the intricates of such complex processes will help to further understand the pathogenesis of DKD and develop better prevention and treatment options.

Transcriptional Analysis-Based Alterations Affecting Neuritogenesis of the Peripheral Nervous System in Psoriasis

An increasing amount of evidence indicates the critical role of the cutaneous nervous system in the initiation and maintenance of psoriatic skin lesions by neurogenic inflammation. However, molecular mechanisms affecting cutaneous neurons are largely uncharacterized. Therefore, we reanalyzed a psoriatic RNA sequencing dataset from published transcriptome experiments of nearly 300 individuals. Using the Ingenuity Pathway Analysis software, we associated several hundreds of differentially expressed transcripts (DETs) to nervous system development and functions. Since neuronal projections were previously reported to be affected in psoriasis, we performed an in-depth analysis of neurite formation-related process. Our in silico analysis suggests that SEMA-PLXN and ROBO-DCC-UNC5 regulating axonal growth and repulsion are differentially affected in non-lesional and lesional skin samples. We identified opposing expressional alterations in secreted ligands for axonal guidance signaling (RTN4/NOGOA, NTNs, SEMAs, SLITs) and non-conventional axon guidance regulating ligands, including WNT5A and their receptors, modulating axon formation. These differences in neuritogenesis may explain the abnormal cutaneous nerve filament formation described in psoriatic skin. The processes also influence T-cell activation and infiltration, thus highlighting an additional angle of the crosstalk between the cutaneous nervous system and the immune responses in psoriasis pathogenesis, in addition to the known neurogenic pro-inflammatory mediators.

Impact of radiation therapy on healthy tissues

Radiation therapy has a fundamental role in the management of cancers. However, despite a constant improvement in radiotherapy techniques, the issue of radiation-induced side effects remains clinically relevant. Mechanisms of acute toxicity and late fibrosis are therefore important topics for translational research to improve the quality of life of patients treated with ionizing radiations. Tissue changes observed after radiotherapy are consequences of complex pathophysiology, involving macrophage activation, cytokine cascade, fibrotic changes, vascularization disorders, hypoxia, tissue destruction and subsequent chronic wound healing. Moreover, numerous data show the impact of these changes in the irradiated stroma on the oncogenic process, with interplays between tumor radiation response and pathways involved in the fibrotic process. The mechanisms of radiation-induced normal tissue inflammation are reviewed, with a focus on the impact of the inflammatory process on the onset of treatment-related toxicities and the oncogenic process. Possible targets for pharmacomodulation are also discussed.

The Identification of the Biomarkers of Sheng-Ji Hua-Yu Formula Treated Diabetic Wound Healing Using Modular Pharmacology

Sheng-Ji Hua-Yu (SJHY) formula has been proved to reduce the severity of diabetic wound healing without significant adverse events in our previous clinical trials. However, based on multi-target characteristics, the regulatory network among herbs, ingredients, and hub genes remains to be elucidated. The current study aims to identify the biomarkers of the SJHY formula for the treatment of diabetic wound healing. First, a network of components and targets for the SJHY formula was constructed using network pharmacology. Second, the ClusterONE algorithm was used to build a modular network and identify hub genes along with kernel pathways. Third, we verified the kernel targets by molecular docking to select hub genes. In addition, the biomarkers of the SJHY formula were validated by animal experiments in a diabetic wound healing mice model. The results revealed that the SJHY formula downregulated the mRNA expression of Cxcr4, Oprd1, and Htr2a, while upregulated Adrb2, Drd, Drd4, and Hrh1. Besides, the SJHY formula upregulated the kernel pathways, neuroactive ligand-receptor interaction, and cAMP signaling pathway in the skin tissue homogenate of the diabetic wound healing mice model. In summary, this study identified the potential targets and kernel pathways, providing additional evidence for the clinical application of the SJHY formula for the treatment of diabetic wound healing.

An optimized derivative of an endogenous CXCR4 antagonist prevents atopic dermatitis and airway inflammation

Aberrant CXCR4/CXCL12 signaling is involved in many pathophysiological processes such as cancer and inflammatory diseases. A natural fragment of serum albumin, named EPI-X4, has previously been identified as endogenous peptide antagonist and inverse agonist of CXCR4 and is a promising compound for the development of improved analogues for the therapy of CXCR4-associated diseases. To generate optimized EPI-X4 derivatives we here performed molecular docking analysis to identify key interaction motifs of EPI-X4/CXCR4. Subsequent rational drug design allowed to increase the anti-CXCR4 activity of EPI-X4. The EPI-X4 derivative JM#21 bound CXCR4 and suppressed CXCR4-tropic HIV-1 infection more efficiently than the clinically approved small molecule CXCR4 antagonist AMD3100. EPI-X4 JM#21 did not exert toxic effects in zebrafish embryos and suppressed allergen-induced infiltration of eosinophils and other immune cells into the airways of animals in an asthma mouse model. Moreover, topical administration of the optimized EPI-X4 derivative efficiently prevented inflammation of the skin in a mouse model of atopic dermatitis. Thus, rationally designed EPI-X4 JM#21 is a novel potent antagonist of CXCR4 and the first CXCR4 inhibitor with therapeutic efficacy in atopic dermatitis. Further clinical development of this new class of CXCR4 antagonists for the therapy of atopic dermatitis, asthma and other CXCR4-associated diseases is highly warranted.

Beyond PROX1: transcriptional, epigenetic, and noncoding RNA regulation of lymphatic identity and function

The lymphatic vascular system acts as the major transportation highway of tissue fluids, and its activation or impairment is associated with a wide range of diseases. There has been increasing interest in understanding the mechanisms that control lymphatic vessel formation (lymphangiogenesis) and function in development and disease. Here, we discuss recent insights into new players whose identification has contributed to deciphering the lymphatic regulatory code. We reveal how lymphatic endothelial cells, the building blocks of lymphatic vessels, utilize their transcriptional, post-transcriptional, and epigenetic portfolio to commit to and maintain their vascular lineage identity and function, with a particular focus on development.

The Role of Chemokines in Psoriasis-An Overview

By participating in both the recruitment and activation of T lymphocytes, macrophages and neutrophils at the site of psoriatic inflammation, chemokines play an important role in the pathogenesis of psoriasis and, crucially, may be one indicator of the response to the systemic treatment of the disease. As a result of their major involvement in both physiological and pathological processes, both chemokines and their receptors have been identified as possible therapeutic targets. Due to their presence in the inflammatory process, they play a role in the pathogenesis of diseases that often coexist with psoriasis, such as atherosclerosis and psoriatic arthritis. Chemokines, cytokines and adhesion molecules may be biological markers of disease severity in psoriasis. However, the mechanism of inflammation in psoriasis is too complex to select only one marker to monitor the disease process and improvement after treatment. The aim of this review was to summarize previous reports on the role of chemokines in the pathogenesis of psoriasis, its treatment and comorbidities.

Investigations on T cell transmigration in a human skin-on-chip (SoC) model

A microfluidics-based three-dimensional skin-on-chip (SoC) model is developed in this study to enable quantitative studies of transendothelial and transepithelial migration of human T lymphocytes in mimicked skin inflammatory microenvironments and to test new drug candidates. The keys results include 1) CCL20-dependent T cell transmigration is significantly inhibited by an engineered CCL20 locked dimer (CCL20LD), supporting the potential immunotherapeutic use of CCL20LD for treating skin diseases such as psoriasis; 2) transepithelial migration of T cells in response to a CXCL12 gradient mimicking T cell egress from the skin is significantly reduced by a sphingosine-1-phosphate (S1P) background, suggesting the role of S1P for T cell retention in inflamed skin tissues; and 3) T cell transmigration is induced by inflammatory cytokine stimulated epithelial cells in the SoC model. Collectively, the developed SoC model recreates a dynamic multi-cellular micro-environment that enables quantitative studies of T cell transmigration at a single cell level in response to physiological cutaneous inflammatory mediators and potential drugs.

Skin-resident natural killer T cells participate in cutaneous allergic inflammation in atopic dermatitis

BACKGROUND

Natural killer T (NKT) cells are unconventional T cells that bridge innate and adaptive immunity. NKT cells have been implicated in the development of atopic dermatitis (AD).

OBJECTIVE

We aimed to investigate the role of NKT cells in AD development, especially in skin.

METHODS

Global proteomic and transcriptomic analyses were performed by using skin and blood from human healthy-controls and patients with AD. Levels of CXCR4 and CXCL12 expression in skin NKT cells were analyzed in human AD and mouse AD models. By using parabiosis and intravital imaging, the role of skin CXCR4⁺ NKT cells was further evaluated in models of mice with AD by using CXCR4-conditionally deficient or CXCL12 transgenic mice.

RESULTS

CXCR4 and its cognate ligand CXCL12 were significantly upregulated in the skin of humans with AD by global transcriptomic and proteomic analyses. CXCR4⁺ NKT cells were enriched in AD skin, and their levels were consistently elevated in our models of mice with AD. Allergen-induced NKT cells participate in cutaneous allergic inflammation. Similar to tissue-resident memory T cells, the predominant skin NKT cells were CXCR4⁺ and CD69⁺. Skin-resident NKT cells uniquely expressed CXCR4, unlike NKT cells in the liver, spleen, and lymph nodes. Skin fibroblasts were the main source of CXCL12. CXCR4⁺ NKT cells preferentially trafficked to CXCL12-rich areas, forming an enriched CXCR4⁺ tissue-resident NKT cells/CXCL12⁺ cell cluster that developed in acute and chronic allergic inflammation in our models of mice with AD.

CONCLUSIONS

CXCR4⁺ tissue-resident NKT cells may form a niche that contributes to AD, in which CXCL12 is highly expressed.

Increased Frequency of CTLA-4 and PD-1 Expressing Regulatory T Cells and Basophils With an Activating Profile in Infants With Moderate-to-Severe Atopic Dermatitis Hypersensitized to Food Allergens

Background: Infants with severe atopic dermatitis (AD) may be sensitized to foods that have not been introduced into their diet, posing a risk for developing an immediate hypersensitivity reaction on the first exposure to the food to which they are sensitized. The aim of this work was to perform an analysis of the sensitization profile in infants with moderate-to-severe AD and to identify cellular and molecular markers for food allergy (FA). Methods: Blood samples from healthy donors and children with moderate-to-severe AD were studied. Specific IgE to several allergens were determined using ImmunoCAP FEIA system and ISAC technology. Furthermore, using flow cytometry-based studies, basophils and regulatory T (Treg) cells were phenotypically characterized. Results: 90% of children with AD were sensitized to food antigens before introducing them into the diet, and 100% developed FA. Phenotypic analysis showed a significantly higher percentage of CTLA-4 and PD-1 expressing Treg cells in AD patients than in healthy controls. Basophils from patients exhibited a marked reduction in the expression of CD300a, higher expression of FcεRI and CXCR4, and to some extent higher expression of CD63 and CD300c. Conclusions: Infants with moderate-to-severe AD are at high risk of being sensitized to food allergens. Therefore, to avoid allergic reactions, broad-spectrum sensitization studies are necessary before introducing complementary diet. Increased expression of CTLA-4 and PD-1 suggests greater suppressive potential of Treg cells in infants with AD than healthy controls. Furthermore, our results suggest a role for CD300 molecules on circulating basophils as possible biomarkers for FA susceptibility.

Effects of a complex mixture prepared from agrimonia, houttuynia, licorice, peony, and phellodendron on human skin cells

Active ingredients derived from natural sources are widely utilized in many industries. Cosmetic active ingredients are largely derived from various plants. In this study, we examined whether a mixture of plant extracts obtained from agrimonia, houttuynia, licorice, peony, and phellodendron (hereafter AHLPP), which are well-known for their effects on skin, could affect skin barrier function, inflammation, and aging in human skin cells. We also determined whether AHLPP extracts sterilized using γ-irradiation (to avoid preservatives) retained their skin cell regulating activity. The AHLPP mixture could downregulate representative pro-inflammatory cytokines including IL 1-β and IL 7. Procollagen peptide synthesis was also increased by AHLPP treatment along with mRNA upregulation of barrier proteins such as filaggrin and desmoplakin. The AHLPP mixture showed an anti-aging effect by significantly upregulating telomerase activity in human keratinocytes. We further observed TERT upregulation and CDKN1B downregulation, implying a weakening of pro-aging signal transduction. Co-cultivation of a hydrogel polymer containing the AHLPP mixture with human skin cells showed an alteration in skin-significant genes such as FLG, which encodes filaggrin. Thus, the AHLPP mixture with or without γ-irradiation can be utilized for skin protection as it alters the expression of some significant genes in human skin cells.

Prospective Translational Study Investigating Molecular PrEdictors of Resistance to First-Line PazopanIb in Metastatic reNal CEll Carcinoma (PIPELINE Study)

OBJECTIVES

Despite the initial clinical benefit, resistance to antiangiogenic therapies develops through the activation of alternative pathways. We measured plasma levels of circulating angiogenic factors to explore their predictive role in metastatic renal cell carcinoma (mRCC) patients treated with pazopanib.

MATERIALS AND METHODS

mRCC patients receiving first-line pazopanib were prospectively enrolled. The levels of circulating interleuchine (IL)-6, IL-8, stromal derived factor-1, vascular endothelial growth factor-A, hepatocyte growth factor (HGF), osteopontin, and E-selectin were quantified at baseline and every 4 weeks until disease progression (PD). Patients were dichotomized into "low" and "high" subgroups by a cutoff point defined by the respective median circulating angiogenic factor (CAF) value at baseline. Then, association with the objective response was determined. Changes in CAF levels between baseline and PD were also compared.

RESULTS

Among 25 patients included in the final data set, 6 patients were still on treatment. As best response, 12 patients presented a partial response (48%), 9 showed stable disease, and 4 showed PD. The median follow-up was 31.9 months. The median progression-free survival was 14.8 months. Low baseline levels of IL-6, IL-8, HGF, and osteopontin were found to be significantly associated with objective response. In addition, patients with low baseline levels of HGF showed longer progression-free survival and overall survival, whereas patients with low baseline levels of IL-8 showed longer overall survival. Among patients experiencing PD, the median plasma levels of stromal derived factor-1 and vascular endothelial growth factor-A were significantly higher compared with the baseline (P=0.01; P=0.011). Conversely, the median levels of E-selectin were significantly lower compared with the baseline (P=0.017).

CONCLUSION

Changes in levels of selected CAFs were associated with response/resistance to pazopanib in mRCC patients.

Emerging Role of CXCR4 in Fibrosis

Recent evidence has shown that the chemokine receptor CXCR4 and its natural chemokine ligand CXCL12 promote pro-inflammatory responses in a variety of situations and this axis has emerged as a central player in tissue fibrosis. Although its role as a co-receptor for human immunodeficiency virus (HIV) and a key player in various cancers has been well established, the role of CXCR4 in various types of fibrosis has emerged only recently. This review will explore the involvement of CXCR4 in the development of fibrosis, focusing mainly on lung, kidney and eye fibrosis.

FOXO1 regulates developmental lymphangiogenesis by upregulating CXCR4 in the mouse-tail dermis

Lymphangiogenesis plays important roles in normal fetal development and postnatal growth. However, its molecular regulation remains unclear. Here, we have examined the function of forkhead box protein O1 (FOXO1) transcription factor, a known angiogenic factor, in developmental dermal lymphangiogenesis using endothelial cell-specific FOXO1-deficient mice. FOXO1-deficient mice showed disconnected and dilated lymphatic vessels accompanied with increased proliferation and decreased apoptosis in the lymphatic capillaries. Comprehensive DNA microarray analysis of the causes of in vivo phenotypes in FOXO1-deficient mice revealed that the gene encoding C-X-C chemokine receptor 4 (CXCR4) was the most drastically downregulated in FOXO1-deficient primary lymphatic endothelial cells (LECs). CXCR4 was expressed in developing dermal lymphatic capillaries in wild-type mice but not in FOXO1-deficient dermal lymphatic capillaries. Furthermore, FOXO1 suppression impaired migration toward the exogenous CXCR4 ligand, C-X-C chemokine ligand 12 (CXCL12), and coordinated proliferation in LECs. These results suggest that FOXO1 serves an essential role in normal developmental lymphangiogenesis by promoting LEC migration toward CXCL12 and by regulating their proliferative activity. This study provides valuable insights into the molecular mechanisms underlying developmental lymphangiogenesis.

Synthesis and evaluation of 2,5-furan, 2,5-thiophene and 3,4-thiophene-based derivatives as CXCR4 inhibitors

The interaction between G-Protein coupled receptor CXCR4 and its natural ligand CXCL12 has been linked to inflammation experienced by patients with Irritable Bowel Disease (IBD). Blocking this interaction could potentially reduce inflammatory symptoms in IBD patients. In this work, several thiophene-based and furan-based compounds modeled after AMD3100 and WZ811-two known antagonists that interrupt the CXCR4-CXCL12 interaction-were synthesized and analyzed. Fifteen hit compounds were identified; these compounds exhibited effective concentrations (EC) lower than 1000 nM (AMD3100) and inhibited invasion of metastatic cells by at least 45%. Selected compounds (2d, 2j, 8a) that inhibited metastatic invasion at a higher rate than WZ811 (62%) were submitted for a carrageenan inflammation test, where both 8a and 2j reduced inflammation in the same range as WZ811 (40%) but did not reduce inflammation more than 40%. Select compounds were also modeled in silico to show key residue interactions. These preliminary results with furan-based and thiophene-based analogues contribute to the new class on heterocyclic aromatic-based CXCR4 antagonists.

Evaluation of the expression of the stromal cell-derived factor-1 alpha (CXCL 12) in psoriatic patients after treatment with Methotrexate

BACKGROUND

CXCL12 has an important role in skin homeostasis and inflammation.

OBJECTIVE

In this work, the expression of CXCL12 was evaluated in psoriasis vulgaris, psoriatic arthritis (PsA) patients in relation to disease activity and methotrexate (MTX) therapy.

METHODS

Skin biopsies were obtained from 10 psoriasis vulgaris patients, 10 PsA patients, and 20 controls. The biopsies were repeated 6 weeks after MTX therapy. The biopsies were stained immunohistochemically by stromal dermal factor 1 alpha (CXCL 12) antibody.

RESULTS

Psoriatic arthritis showed significantly more expression of CXCL 12 than psoriasis vulgaris patients before treatment but not after treatment. There was significant decrease in CXCL 12 expression in the keratinocytes of psoriasis vulgaris patients after MTX therapy than before treatment, P-value was 0.009. There was no significant difference between pre- and post-treatment in the CXCL 12 expression of keratinocytes of PsA patients, P-value was 0.093. The percentage decrease of PASI score after treatment showed a moderate correlation with the percentage decrease of CXCL12 expression of the keratinocytes of the total psoriasis patients, r = 0.484, P-value was 0.015.

CONCLUSION

CXCL12 might be involved in the progression of psoriasis vulgaris to PsA. MTX therapy downregulated the expression of CXCL12 of the keratinocytes of psoriasis patients. This downregulation was paralleled by decrease in the PASI score. CXCL12 can be used as a biological marker of disease severity of psoriasis patients.

Development of CXCR4 modulators based on the lead compound RB-108

The CXCR4/CXCL12 axis plays prominent roles in tumor metastasis and inflammation. CXCR4 has been shown to be involved in a variety of inflammation-related diseases. Therefore, CXCR4 is a promising potential target to develop novel anti-inflammatory agents. Taking our previously discovered CXCR4 modulator RB-108 as the lead compound, a series of derivatives were synthesized structurally modifying and optimizing the amide and sulfamide side chains. The derivatives successfully maintained potent CXCR4 binding affinity. Furthermore, compounds IIb, IIc, IIIg, IIIj, and IIIm were all efficacious in inhibiting the invasion of CXCR4-positive cells, displaying a much more potent effect than the lead compound RB-108. Notably, compound IIIm significantly decreased carrageenan-induced swollen volume and paw thickness in a mouse paw edema model. More importantly, IIIm exhibited satisfying PK profiles with a half-life of 4.77 h in an SD rat model. In summary, we have developed compound IIIm as a new candidate for further investigation based on the lead compound RB-108.

Facilitation of Chemotaxis Activity of Mesenchymal Stem Cells via Stromal Cell-Derived Factor-1 and Its Receptor May Promote Ectopic Ossification of Human Spinal Ligaments

Mesenchymal stem cells (MSCs) have been used to elucidate the pathogenesis of numerous diseases. Our recent study showed that MSCs may conduce to the ossification of spinal ligaments. Stromal cell-derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) regulate MSC migration. Moreover, their expression is elevated in sites of damage and remodeling in pathologic states. We explored the possible role of the SDF-1/CXCR4 axis in the chemotactic behavior of MSCs in the ossification of spinal ligaments. Specimens of thoracic vertebra ossified ligamentum flavum (OLF) and non-OLF plaques were received from patients in whom we had performed spine surgery. Paraffin-embedded tissue sections were prepared for immunohistochemical staining. Cultured MSCs from the ligamentum flavum were prepared for in vitro analyses. We observed SDF-1 and CXCR4 localization immunohistochemically in the perivascular area and collagenous matrix of ligaments and in chondrocytes near the ossification front of OLF. And then, immunohistochemical staining showed a close relationship between MSCs and the SDF-1/CXCR4 axis. In the in vitro analyses, expression of the SDF-1/CXCR4 and the migratory capacity of MSCs in OLF were remarkably higher compared with non-OLF MSCs. Furthermore, the migration of MSCs was upregulated by SDF-1 and downregulated by treatment with AMD3100 (C28H54N88HCl), a specific antagonist for CXCR4. All in vitro test data showed a significant difference in MSCs from OLF compared with non-OLF MSCs. Our results reveal that the SDF-1/CXCR4 axis may contribute to an MSC-mediated increase in the ossification process, indicating that the SDF-1/CXCR4 axis may become a potential target for a novel therapeutic strategy for ossification of spinal ligaments.

The Role of the CXCL12/CXCR4/ACKR3 Axis in Autoimmune Diseases

Chemokine receptors are members of the G protein-coupled receptor superfamily. These receptors are intimately involved in cell movement, and thus play a critical role in several physiological and pathological situations that require the precise regulation of cell positioning. CXCR4 is one of the most studied chemokine receptors and is involved in many functions beyond leukocyte recruitment. During embryogenesis, it plays essential roles in vascular development, hematopoiesis, cardiogenesis, and nervous system organization. It has been also implicated in tumor progression and autoimmune diseases and, together with CD4, is one of the co-receptors used by the HIV-1 virus to infect immune cells. In contrast to other chemokine receptors that are characterized by ligand promiscuity, CXCR4 has a unique ligand-stromal cell-derived factor-1 (SDF1, CXCL12). However, this ligand also binds ACKR3, an atypical chemokine receptor that modulates CXCR4 functions and is overexpressed in multiple cancer types. The CXCL12/CXCR4/ACKR3 axis constitutes a potential therapeutic target for a wide variety of inflammatory diseases, not only by interfering with cell migration but also by modulating immune responses. Thus far, only one antagonist directed against the ligand-binding site of CXCR4, AMD3100, has demonstrated clinical relevance. Here, we review the role of this ligand and its receptors in different autoimmune diseases.

Macrophage Migration Inhibitory Factor (MIF) Drives Murine Psoriasiform Dermatitis

The immunomodulator Macrophage Migration Inhibitory Factor (MIF) exerts pleiotropic immunomodulatory activities and has been implicated in the pathogenesis of diverse inflammatory diseases. Expression levels of MIF are also significantly elevated in the skin and serum of psoriasis patients, but the pathogenic significance of MIF in psoriasis is unknown. We have therefore addressed the role of MIF in two mouse models of psoriasis, namely in the imiquimod-induced psoriasiform dermatitis (IIPD) and the IL-23-induced dermatitis model. Daily treatment with Aldara™ cream, containing imiquimod, markedly increased the abundance of MIF in the skin and generated a cellular skin expression pattern of MIF closely resembling that in human plaque psoriasis. Deficiency in MIF significantly alleviated IIPD. On the clinical level, all hallmarks of psoriasiform dermatitis, including erythema, skin infiltration, and desquamation were reduced in Mif^−/− mice. On the histopathological level, MIF deficiency decreased keratinocyte hyperproliferation, inflammatory cell infiltration, specifically with respect to monocyte-derived cells, and dermal angiogenesis, suggesting that MIF may be involved in the pathogenesis of psoriasiform dermatitis through several mechanisms. Similarly, MIF deficiency also significantly reduced disease in the IL-23-induced dermatitis model, suggesting that MIF is involved in the pathogenic pathways activated by IL-23 and required to achieve full-blown psoriasiform dermatitis. Collectively, our results lend support to a possible disease-promoting role of MIF in psoriasis, which should be further investigated.

Senescent fibroblasts drive ageing pigmentation: ​A potential therapeutic target for senile lentigo

Cutaneous ageing is an important extrinsic process that modifies the pigmentary system. Because cellular senescence is a fundamental ageing mechanism, we examined the role of senescent cells in ageing pigmentation.

Methods: Biopsies obtained from senile lentigo and perilesional normal skin were assayed for a marker of cellular senescence, p16^INK4A. To determine the secretory phenotypes of senescent fibroblasts, we performed microarray, RNA sequencing and methylation array analyses in senile lentigo and senescent fibroblasts. To further investigate the impact of senescent cells on ageing-related pigmentation, an intervention that targeted senescent cells using radiofrequency was performed.

Results:In vivo, senescent fibroblasts accumulated at the sites of age-related pigmentation. Phenotype switching of the cells resulted in the repression of stromal-derived factor 1 (SDF1) by promoter methylation. SDF1 induced melanocyte differentiation via stromal-epithelial interactions, ultimately driving skin pigmentation. Furthermore, the elimination of senescent fibroblasts from pigmented skin using radiofrequency was accompanied by skin lightening, rendering it a potential target for treatment.

Conclusion: Aged pigmented skin contains an increasing proportion of senescent fibroblasts. Cells with phenotype switching exhibited a loss of SDF1, which stimulates the melanogenic process and thereby contributes to aging pigmentation. These data may promote the development of new therapeutic paradigms, such as a stroma-targeting therapy for pigmentary disorders.

Lymphatic exosomes promote dendritic cell migration along guidance cues

Inflammation stimulates lymphatic endothelial cells to release exosomes, which accumulate in the perivascular stroma. Brown et al. show that these exosomes promote the directional migration of dendritic cells along guidance cues in complex environments by enhancing dynamic cellular protrusions in a CX3CL1-dependent manner.

Lymphatic endothelial cells (LECs) release extracellular chemokines to guide the migration of dendritic cells. In this study, we report that LECs also release basolateral exosome-rich endothelial vesicles (EEVs) that are secreted in greater numbers in the presence of inflammatory cytokines and accumulate in the perivascular stroma of small lymphatic vessels in human chronic inflammatory diseases. Proteomic analyses of EEV fractions identified >1,700 cargo proteins and revealed a dominant motility-promoting protein signature. In vitro and ex vivo EEV fractions augmented cellular protrusion formation in a CX3CL1/fractalkine-dependent fashion and enhanced the directional migratory response of human dendritic cells along guidance cues. We conclude that perilymphatic LEC exosomes enhance exploratory behavior and thus promote directional migration of CX3CR1-expressing cells in complex tissue environments.

Instructive microenvironments in skin wound healing: Biomaterials as signal releasing platforms

Skin wound healing aims to repair and restore tissue through a multistage process that involves different cells and signalling molecules that regulate the cellular response and the dynamic remodelling of the extracellular matrix. Nowadays, several therapies that combine biomolecule signals (growth factors and cytokines) and cells are being proposed. However, a lack of reliable evidence of their efficacy, together with associated issues such as high costs, a lack of standardization, no scalable processes, and storage and regulatory issues, are hampering their application. In situ tissue regeneration appears to be a feasible strategy that uses the body's own capacity for regeneration by mobilizing host endogenous stem cells or tissue-specific progenitor cells to the wound site to promote repair and regeneration. The aim is to engineer instructive systems to regulate the spatio-temporal delivery of proper signalling based on the biological mechanisms of the different events that occur in the host microenvironment. This review describes the current state of the different signal cues used in wound healing and skin regeneration, and their combination with biomaterial supports to create instructive microenvironments for wound healing.

Cytokine and Chemokine Profiling in Patients with Hand, Foot and Mouth Disease in Singapore and Malaysia

Hand, foot and mouth disease (HFMD) is a prevalent contagious childhood disease typically associated with fever, oral lesions and limb exanthema. While HFMD is caused by a plethora of serotypes of viruses under the genus Enterovirus within the Picornaviridae family, Coxsackievirus A16 (CV-A16) and Enterovirus 71 (EV-A71) are considered the main etiological agents. In recent years however, other viruses have also been isolated in considerable numbers from infected individuals in many regions, joining the legion commonly associated with HFMD. The present study investigated the cytokine and chemokine profiles of HFMD patients from Singapore and Malaysia for the first time. Comparative cohort studies of EV-A71-associated HFMD cases revealed that the Malaysia cohort had a distinct profile from the Singapore cohort, and this could be partly attributed by different EV-A71 genotypes. As the isolation of CV-A6, instead of CV-A16, had become prevalent in the Singapore cohort, it was also of particular interest to study the differential cytokine and chemokine profiles. Our data revealed that overlapping as well as unique profiles exist between the two major causative clinical isolates in the Singapore cohort. Having a better understanding of the respective immunological profiles could be useful for more accurate HFMD diagnosis, which is imperative for disease transmission control until multi-valent vaccines and/or broad-spectrum anti-viral drugs become available.

Alcohol-Mediated Organ Damages: Heart and Brain

Alcohol is one of the most commonly abused substances in the United States. Chronic consumption of ethanol has been responsible for numerous chronic diseases and conditions globally. The underlying mechanism of liver injury has been studied in depth, however, far fewer studies have examined other organs especially the heart and the central nervous system (CNS). The authors conducted a narrative review on the relationship of alcohol with heart disease and dementia. With that in mind, a complex relationship between inflammation and cardiovascular disease and dementia has been long proposed but inflammatory biomarkers have gained more attention lately. In this review we examine some of the consequences of the altered cytokine regulation that occurs in alcoholics in organs other than the liver. The article reviews the potential role of inflammatory markers such as TNF-α in predicting dementia and/or cardiovascular disease. It was found that TNF-α could promote and accelerate local inflammation and damage through autocrine/paracrine mechanisms. Unraveling the mechanisms linking chronic alcohol consumption with proinflammatory cytokine production and subsequent inflammatory signaling pathways activation in the heart and CNS, is essential to improve our understanding of the disease and hopefully facilitate the development of new remedies.

Role of the stromal cell derived factor-1/CXC chemokine receptor 4 axis in the invasion and metastasis of lung cancer and mechanism

Background

Lung cancer is the most common tumor, and has the highest incidence and mortality rates among all malignant tumors. Since stromal cell derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) are specific to binding sites, they are more important than other members of the families for tumor invasion and metastasis. We herein aimed to investigate the role of the axis of chemokine SDF-1 and its receptor CXCR4 in the invasion and metastasis of lung cancer.

Methods

Sixty clinical non-small cell lung cancer (NSCLC) tissue samples were collected. The CXCR4 expressions in cancer, paracancerous and normal lung tissues were detected by immunocytochemical assay and PCR. Cells with CXCR4 overexpression (CXCR4-A549) were constructed. After induction with SDF-1, CXCR4-A549 and A549 cells were subjected to in vitro chemotaxis and invasion assays. Their proliferation and apoptosis were detected by flow cytometry. The activities of phosphoinositide 3-kinase/protein kinase B (AKT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK)-related signaling pathways were detected by Western blot. The downstream signaling molecules that may be activated by SDF-1/CXCR4 were analyzed. The expressions of vascular endothelial growth factor-C and matrix metalloproteinase-2 were detected by Western blot and PCR. A mouse model was established by subcutaneous inoculation of lung cancer cells. The effects of up-regulated CXCR4 expression on the migration of lung cancer cells in vitro and their tumorigenesis and metastasis in vivo were assessed.

Results

There was no expression in normal or paracancerous tissues. The expression of CXCR4 mRNA in lung cancer tissues was 83.3% (50/60). The expressions of CXCR4 in lung squamous cell carcinoma and adenocarcinoma were similar (P>0.05). The expression of CXCR4 was 76.9% (10/13) in highly differentiated carcinoma, 82.1% (23/28) in moderately differentiated carcinoma and 84.2% (16/19) in lowly differentiated carcinoma (P>0.05). The expression of CXCR4 was 72.7% (8/11) in TNM stage I patients, 83.9% (26/31) in stage II patients, and 88.9% (16/18) in stage III patients, with significant correlations. After up-regulation of CXCR4, the invasion ability of CXCR4-A549 cells was increased 1.62-fold (P<0.05). ERK and AKT were significantly phosphorylated 30 min after SDF-1 treatment. The tumorigenic rates of six mice inoculated with CXCR4-A549 and A549 cells were both 100%, with the average tumor weights of (4.37±0.96 g) and (3.24±1.16 g) respectively (P<0.05). In the CXCR4-A549 group, metastatic tumors clearly formed in the lungs of 6 mice, but only 2 mice in the A549 group had tumor cell invasion.

Conclusions

SDF-1/CXCR4 played a key role in the invasion and metastasis of lung cancer. The interaction between SDF-1α and CXCR4 activated a series of downstream molecules by activating ERK and AKT.

Leveraging the IncuCyte Technology for Higher-Throughput and Automated Chemotaxis Assays for Target Validation and Compound Characterization

Chemotaxis is the directional movement of cells in response to a chemical stimulus and is vital for many physiological processes, including immune responses, tumor metastasis, wound healing, and blood vessel formation. Therefore, modulation of chemotaxis is likely to be of therapeutic benefit. Hence, a high-throughput means to conduct chemotaxis assays is advantageous for lead evaluation and optimization in drug discovery. In this study, we have validated a novel approach for a higher-throughput, label-free, image-based IncuCyte chemotaxis assay encompassing various cell types, including T cells, B cells, mouse Th17, immature and mature dendritic cells, monocyte THP-1, CCRF-CEM, monocytes, neutrophils, macrophages, and MDA-MB-231. These assays enable us to visualize chemotactic cell migration in real time and perform kinetic cell motility studies on an automated platform, thereby allowing us to incorporate the quantitative studies of cell migration behavior into a routine drug discovery screening cascade.