The Expression of CXCL10/CXCR3 and Effect of the Axis on the Function of T Lymphocyte Involved in Oral Lichen Planus

A tissue-engineered model of T-cell mediated oral mucosal inflammatory disease

T-cell-mediated oral mucocutaneous inflammatory conditions including oral lichen planus (OLP) are common but development of new treatments aimed at relieving symptoms and controlling OLP progression are hampered by the lack of experimental models. Here, we developed a tissue-engineered oral mucosal equivalent (OME) containing polarised T-cells to replicate OLP pathogenesis. Peripheral blood CD4+ and CD8+ T-cells were isolated, activated and polarised into Th1 and cytotoxic T-cells (Tc). OME were constructed by culturing oral keratinocytes on an oral fibroblast-populated hydrogel to produce a stratified squamous epithelium. OME stimulated with IFN-γ and TNF-α or medium from Th1 cells caused increased secretion of inflammatory cytokines/chemokines. A model of T-cell-mediated inflammatory disease was developed by combining OME on top of a Th1/Tc-containing hydrogel, followed by epithelial stimulation with IFN-γ/TNF-α. T-cell recruitment towards the epithelium was associated with increased secretion of T-cell chemoattractants CCL5, CXCL9 and CXCL10. Histological assessment showed tissue damage associated with cleaved-caspase-3 and altered laminin-5 expression. Treatment with inhibitors directed against JAK, KCa3.1 channels or clobetasol in solution and/or via a mucoadhesive patch prevented cytokine/chemokine release and tissue damage. This disease model has potential to probe for mechanisms of pathogenesis or as a test platform for novel therapeutics or treatment modalities.

Potential different immune phenotypes of macrophages in oral lichen planus by integrating immunofluorescence double staining and single-cell RNA sequencing

Background/purpose

Oral lichen planus (OLP) is a chronic inflammatory disease with obscure etiopathogenesis. Macrophages play an important role in interaction between innate and adaptive immunity. This study aimed to investigate the macrophage phenotypes and obtain more comprehensive gene characteristics of macrophages in OLP.

Materials and methods

Double cluster of differentiation (CD) 68/CD86 and CD68/CD206 immunofluorescence staining was conducted in 11 biopsy-proven OLP tissue samples and 5 health control (HC) to represent M1 and M2 macrophages, respectively. The number of positively stained cells was manually counted, and the density was calculated. Furtherly, OLP single-cell dataset GSE211630 was downloaded from Gene Expression Omnibus. Gene characteristics and functional analysis of the macrophages were elucidated.

Results

In the OLP group, the densities of M1 (P < 0.001), M2 macrophages (P < 0.001) and M1/M2 ratio (P = 0.001) were significantly higher than those in HC group. Single-cell RNA sequencing revealed that proportions of CXCL10 macrophages (P = 0.003), IL1B/MMP19 macrophages (P < 0.001) were increased in OLP tissues compared with those in HC. Macrophages in OLP tissues had a stronger ability to cell chemotaxis, positive regulation of cell adhesion and antigen processing and presentation. Functional analysis revealed macrophages in OLP tissues could interact with multiple immune cells, and multiple signaling pathways were associated with macrophages in OLP.

Conclusion

A pro-inflammatory status of macrophages with different gene characteristics was found in the microenvironment of OLP by integrating immunofluorescence double staining and single-cell RNA sequencing, which provided a potential target for clinical treatment of OLP.

ASCT2-mediated glutamine uptake of epithelial cells facilitates CCL5-induced T cell infiltration via ROS-STAT3 pathway in oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a chronic inflammatory disease characterized by T cell infiltration at lesion sites. T cell migration is greatly facilitated by chemokines produced by epithelial cells. Studies have noted the potential role of glutamine uptake in OLP and other inflammatory diseases. Here, we investigated the effect of altered glutamine uptake of epithelial cells on T cell infiltration and its underlying mechanisms in OLP.

METHODS

Immunohistochemistry was used to identify the expressions of glutamine transporter alanine-serine-cysteine transporter 2 (ASCT2) and C-C motif chemokine ligand 5 (CCL5) in oral tissues of OLP and healthy controls. Human gingival epithelial cells (HGECs) were treated with glutamine deprivation and ASCT2 inhibiter GPNA respectively to detect the expressions of CCL5 and its related signaling molecules. Additionally, we had determined the impact of epithelial cell-derived CCL5 on T-cell migration using a co-culture system in vitro.

RESULTS

ASCT2 and CCL5 expressions in OLP were significantly higher than healthy controls and positively correlated with the density of inflammatory infiltrations. Glutamine supplement significantly increased CCL5 production in HGECs, which was effectively inhibited by GPNA. Besides, glutamine could inhibit reactive oxygen species (ROS) production to activate the signal transducer and activator of transcription 3 (STAT3) causing higher expression level of CCL5 in HGECs. Simultaneously, T cell migration could be blocked by anti-CCL5 neutralizing antibody and STAT3 inhibitor stattic in the co-culture system.

CONCLUSION

The upregulated ASCT2-mediated glutamine uptake in epithelial cells promotes CCL5 production via ROS-STAT3 signaling, which boosts the T-cell infiltration in OLP lesion.

Electrospun patch delivery of anti-TNFα F(ab) for the treatment of inflammatory oral mucosal disease

Chronic ulcerative oral mucosal inflammatory diseases, including oral lichen planus and recurrent aphthous stomatitis, are painful and highly prevalent, yet lack effective clinical management. In recent years, systemic biologic therapies, including monoclonal antibodies that block the activity of cytokines, have been increasingly used to treat a range of immune-mediated inflammatory conditions such as rheumatoid arthritis and psoriasis. The ability to deliver similar therapeutic agents locally to the oral epithelium could radically alter treatment options for oral mucosal inflammatory diseases, where pro-inflammatory cytokines, in particular tumour-necrosis factor-α (TNFα), are major drivers of pathogenesis. To address this, an electrospun dual-layer mucoadhesive patch comprising medical-grade polymers was investigated for the delivery of F(ab) biologics to the oral mucosa. A fluorescent-labelled F(ab) was incorporated into mucoadhesive membranes using electrospinning with 97% v/v ethanol as a solvent. The F(ab) was detected within the fibres in aggregates when visualised by confocal microscopy. Biotinylated F(ab) was rapidly eluted from the patch (97 ± 5% released within 3 h) without loss of antigen-binding activity. Patches applied to oral epithelium models successfully delivered the F(ab), with fluorescent F(ab) observed within the tissue and 5.1 ± 1.5% cumulative transepithelial permeation reached after 9 h. Neutralising anti-TNFα F(ab) fragments were generated from whole IgG by papain cleavage, as confirmed by SDS-PAGE, then incorporated into patches. F(ab)-containing patches had TNFα neutralising activity, as shown by the suppression of TNFα-mediated CXCL8 release from oral keratinocytes cultured as monolayers. Patches were applied to lipopolysaccharide-stimulated immune-competent oral mucosal ulcer equivalents that contained primary macrophages. Anti-TNFα patch treatment led to reduced levels of active TNFα along with a reduction in the levels of disease-implicated T-cell chemokines (CCL3, CCL5, and CXCL10) to baseline concentrations. This is the first report of an effective device for the delivery of antibody-based biologics to the oral mucosa, enabling the future development of new therapeutic strategies to treat painful conditions.

Immune mechanisms in oral lichen planus

Oral lichen planus (OLP) is a T-cell-mediated inflammatory disease of the oral mucosa that has been extensively researched over many years but as yet the mechanisms of pathogenesis are still not fully understood. Whilst the specific etiologic factors driving OLP remain ambiguous, evidence points to the development of a chronic, dysregulated immune response to OLP-mediating antigens presented by innate immune cells and oral keratinocytes leading to increased cytokine, chemokine and adhesion molecule expression. These molecules recruit T-cells and mast cells to the diseased site and orchestrate a complex interplay between cells that culminates in keratinocyte cell death, mucosal basement membrane destruction and long-term chronicity of the disease. The main lymphocytes involved are thought to be CD8+ cytotoxic and CD4+ Th1 polarised T-cells although recent evidence indicates the involvement of other Th subsets such as Th9, Th17 and Tregs, suggesting that a more complex immune cell relationship exists during the disease process. This review provides an overview of the immune mechanisms at play in OLP pathogenesis with particular emphasis on the role of the different Th subsets and how these recent discoveries may guide research toward identifying potential therapeutic targets.

Chemokine-Based Therapeutics for the Treatment of Inflammatory and Fibrotic Convergent Pathways in COVID-19

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the SARS-CoV-2 betacoronavirus and has taken over 761,426 American lives as of the date of publication and will likely result in long-term, if not permanent, tissue damage for countless patients. COVID-19 presents with diverse and multisystemic pathologic processes, including a hyperinflammatory response, acute respiratory distress syndrome (ARDS), vascular injury, microangiopathy, tissue fibrosis, angiogenesis, and widespread thrombosis across multiple organs, including the lungs, heart, kidney, liver, and brain. C-X-C chemokines contribute to these pathologies by attracting inflammatory mediators, the disruption of endothelial cell integrity and function, and the initiation and propagation of the cytokine storm. Among these, CXCL10 is recognized as a critical contributor to the hyperinflammatory state and poor prognosis in COVID-19. CXCL10 is also known to regulate growth factor-induced fibrosis, and recent evidence suggests the CXCL10-CXCR3 signaling system may be vital in targeting convergent pro-inflammatory and pro-fibrotic pathways. This review will explore the mechanistic role of CXCL10 and related chemokines in fibrotic complications associated with COVID-19 and the potential of CXCL10-targeted therapeutics for early intervention and long-term treatment of COVID-19-induced fibrosis.

Lichen Planus

Lichen planus (LP) is a T cell-mediated disease affecting the stratified squamous epithelia of the skin and/or mucus membrane. Histologically, the disease is characterized by a lichenoid inflammatory infiltrate and vacuolar degeneration of the basal layer of the epidermis. LP has three major subtypes: Cutaneous, mucosal and appendageal LP. Rarely, it may affect the nails in the absence of skin and/or mucosal changes. LP may also be induced by several drugs, typically anti-hypertensive medication or be associated with infections, particularly viral hepatitis. The diagnosis is based on the clinical presentation and characteristic histological findings. Although the disease is often self-limiting, the intractable pruritus and painful mucosal erosions result in significant morbidity. The current first-line treatment are topical and/or systemic corticosteroids. In addition, immunosuppressants may be used as corticosteroid-sparing agents. These, however are often not sufficient to control disease. Janus kinase inhibitors and biologics (anti-IL-12/23, anti-IL17) have emerged as novel future treatment options. Thus, one may expect a dramatic change of the treatment landscape of LP in the near future.

Cross-talk between CXC chemokine ligand 10-CXC chemokine receptor 3 axis and CC chemokine ligand 17-CC chemokine receptor 4 axis in the pathogenesis of oral lichen planus

OBJECTIVES

This study aimed to determine whether a correlation existed between CXC chemokine ligand 10 (CXCL10)-CXC chemokine receptor 3 (CXCR3) and CC chemokine ligand 17 (CCL17)-CC chemokine receptor 4 (CCR4) in the pathogenesis of oral lichen planus (OLP).

METHODS

Peripheral blood of OLP patients (non-erosive and erosive groups) and healthy controls were collected, and T cells were isolated and purified. T cells were co-cultured with three groups: blank, anti-CXCR3, and anti-CCR4. CXCR3 and CCR4 expression were detected by flow cytometry, and CXCL10 and CCL17 were detected by enzyme-linked immunosorbent assay, respectively.

RESULTS

The purities of T cells were all >95% in the three groups (P>0.05). Receptor expression showed that CXCR3 and CCR4 in the anti-CXCR3 group was downregulated in OLP compared with the blank group (P>0.05). The level of CCR4 in the anti-CCR4 group was significantly downregulated (P<0.05), and CXCR3 was upregulated (P>0.05). Ligand analysis results showed that CXCL10 in the anti-CXCR3 group was significantly downregulated in OLP compared with the blank group (P<0.05), and CCL17 was also downregulated (P>0.05). CCL17 in the anti-CCR4 group was significantly downregulated (P<0.05), and CXCL10 was upregulated (P>0.05). The trend of receptors and ligands in controls was consistent with OLP, but no significant difference existed between the antagonistic and the blank groups (P>0.05).

CONCLUSIONS

Two axes interact with each other in the pathogenesis of OLP and may play different roles in its occurrence and development.

Functional differences of three CXCL10 homologues in the giant spiny frog Quasipaa spinosa

Chemokines are a superfamily of structurally related chemotactic cytokines exerting significant roles in acting as a bridge between the innate and adaptive immune responses. In this study, we identified three CXC motif chemokine 10 (CXCL10) homologues (QsCXCL10-1, QsCXCL10-2 and QsCXCL10-3) from giant spiny frog Quasipaa spinosa. All three deduced QsCXCL10 proteins contained four conserved cysteine residues as found in other known CXC chemokines. Phylogenetic analysis showed that QsCXCL10-1, 2, 3 and other CXCL10s in amphibian were grouped together to form a separate clade. These three QsCXCL10s were highly expressed in spleen and blood. Upon infection with Staphylococcus aureus or Aeromonas hydrophila, the expressions of QsCXCL10s were markedly increased in spleen and blood during biotic stresses. Meanwhile, the QsCXCL10s transcription in liver could also be up-regulated under abiotic stresses such as cold and heat stresses. The recombinant proteins of frog CXCL10 homologues were produced and purified in E. coli and possessed similar but differential bioactivities. Both rCXCL10-1 and rCXCL10-2 had strong effects on the up-regulation of pro-inflammatory cytokines (TNF-α, IL-1β and IL-8) in vivo, whereas rCXCL10-3 induced a weak expression of these cytokines. Moreover, the rCXCL10-1 and rCXCL10-2 could strongly promote splenocyte proliferation and induce lymphocytes migration, while rCXCL10-3 had limited effects on these biological processes. All three frog chemokines triggered their functional activities by engaging CXC motif chemokine receptor 3 (CXCR3). Taken together, these results revealed that the three QsCXCL10s had similar but differential functional activities in mediating immune responses and host defenses, which might contribute to a better understanding of the functional evolution of CXCL10 in vertebrates.