Microwave-assisted Phospha-Michael addition reactions in the 13α-oestrone series and in vitro antiproliferative properties

Microwave-assisted phospha-Michael addition reactions were carried out in the 13α-oestrone series. The exocyclic 16-methylene-17-ketones as α,β-unsaturated ketones were reacted with secondary phosphine oxides as nucleophilic partners. The addition reactions furnished the two tertiary phosphine oxide diastereomers in high yields. The main product was the 16α-isomer. The antiproliferative activities of the newly synthesised organophosphorus compounds against a panel of nine human cancer cell lines were investigated by means of MTT assays. The most potent compound, the diphenylphosphine oxide derivative in the 3-O-methyl-13α-oestrone series (9), exerted selective cell growth-inhibitory activity against UPCI-SCC-131 and T47D cell lines with low micromolar IC₅₀ values. Moreover, it displayed good tumour selectivity property determined against non-cancerous mouse fibroblast cells.     

Novel oxindole/benzofuran hybrids as potential dual CDK2/GSK-3β inhibitors targeting breast cancer: design,synthesis, biological evaluation,and in silico studies

The serine/threonine protein kinases CDK2 and GSK-3β are key oncotargets in breast cancer cell lines, therefore, in the present study three series of oxindole-benzofuran hybrids were designed and synthesised as dual CDK2/GSK-3β inhibitors targeting breast cancer (5a–g, 7a–h, and 13a–b). The N¹-unsubstituted oxindole derivatives, series 5, showed moderate to potent activity on both MCF-7 and T-47D breast cancer cell lines. Compounds 5d–f showed the most potent cytotoxic activity with IC₅₀ of 3.41, 3.45 and 2.27 μM, respectively, on MCF-7 and of 3.82, 4.53 and 7.80 μM, respectively, on T-47D cell lines, in comparison to the used reference standard (staurosporine) IC₅₀ of 4.81 and 4.34 μM, respectively. On the other hand, the N¹-substituted oxindole derivatives, series 7 and 13, showed moderate to weak cytotoxic activity on both breast cancer cell lines. CDK2 and GSK-3β enzyme inhibition assay of series 5 revealed that compounds 5d and 5f are showing potent dual CDK2/GSK-3β inhibitory activity with IC₅₀ of 37.77 and 52.75 nM, respectively, on CDK2 and 32.09 and 40.13 nM, respectively, on GSK-3β. The most potent compounds 5d–f caused cell cycle arrest in the G2/M phase in MCF-7 cells inducing cell apoptosis because of the CDK2/GSK-3β inhibition. Molecular docking studies showed that the newly synthesised N¹-unsubstituted oxindole hybrids have comparable binding patterns in both CDK2 and GSK-3β. The oxindole ring is accommodated in the hinge region interacting through hydrogen bonding with the backbone CO and NH of the key amino acids Glu81 and Leu83, respectively, in CDK2 and Asp133 and Val135, respectively, in GSK-3β. Whereas, in series 7 and 13, the N¹-substitutions on the oxindole nucleus hinder the compounds from achieving these key interactions with hinge region amino acids what rationalises their moderate to low anti-proliferative activity.     

Synthesis and bioactivities evaluation of oleanolic acid oxime ester derivatives as α-glucosidase and α-amylase inhibitors

Different oleanolic acid (OA) oxime ester derivatives (3a-3t) were designed and synthesised to develop inhibitors against α-glucosidase and α-amylase. All the synthesised OA derivatives were evaluated against α-glucosidase and α-amylase in vitro. Among them, compound 3a showed the highest α-glucosidase inhibition with an IC₅₀ of 0.35 µM, which was ∼1900 times stronger than that of acarbose, meanwhile compound 3f exhibited the highest α-amylase inhibitory with an IC₅₀ of 3.80 µM that was ∼26 times higher than that of acarbose. The inhibition kinetic studies showed that the inhibitory mechanism of compounds 3a and 3f were reversible and mixed types towards α-glucosidase and α-amylase, respectively. Molecular docking studies analysed the interaction between compound and two enzymes, respectively. Furthermore, cytotoxicity evaluation assay demonstrated a high level of safety profile of compounds 3a and 3f against 3T3-L1 and HepG2 cells.

Highlights

1. Oleanolic acid oxime ester derivatives (3a–3t) were synthesised and screened against α-glucosidase and α-amylase.
2. Compound 3a showed the highest α-glucosidase inhibitory with IC50 of 0.35 µM.
3. Compound 3f presented the highest α-amylase inhibitory with IC50 of 3.80 µM.
4. Kinetic studies and in silico studies analysed the binding between compounds and α-glucosidase or α-amylase.

     

NADPH–Cytochrome P450 Reductase Mediates the Fatty Acid Desaturation of ω3 and ω6 Desaturases from Mortierella alpina

Fatty acid desaturases play an important role in maintaining the appropriate structure and function of biological membranes. The biochemical characterization of integral membrane desaturases, particularly ω3 and ω6 desaturases, has been limited by technical difficulties relating to the acquisition of large quantities of purified proteins, and by the fact that functional activities of these proteins were only tested in an NADH-initiated reaction system. The main aim of this study was to reconstitute an NADPH-dependent reaction system in vitro and investigate the kinetic properties of Mortierella alpina ω3 and ω6 desaturases in this system. After expression and purification of the soluble catalytic domain of NADPH–cytochrome P450 reductase, the NADPH-dependent fatty acid desaturation was reconstituted for the first time in a system containing NADPH, NADPH–cytochrome P450 reductase, cytochrome b5, M. alpina ω3 and ω6 desaturase and detergent. In this system, the maximum activity of ω3 and ω6 desaturase was 213.4 ± 9.0 nmol min⁻¹ mg⁻¹ and 10.0 ± 0.5 nmol min⁻¹ mg⁻¹, respectively. The highest k_cat/K_m value of ω3 and ω6 desaturase was 0.41 µM⁻¹ min⁻¹ and 0.09 µM⁻¹ min⁻¹ when using linoleoyl CoA (18:2 ω6) and oleoyl CoA (18:1 ω9) as substrates, respectively. M. alpina ω3 and ω6 desaturases were capable of using NADPH as reductant when mediated by NADPH–cytochrome P450 reductase; although, their efficiency is distinguishable from NADH-dependent desaturation. These results provide insights into the mechanisms underlying ω3 and ω6 fatty acid desaturation and may facilitate the production of important fatty acids in M. alpina.     

The GPCR–β-arrestin complex allosterically activates C-Raf by binding its amino terminus

G protein–coupled receptors (GPCRs) convert external stimuli into cellular signals through heterotrimeric guanine nucleotide-binding proteins (G-proteins) and β-arrestins (βarrs). In a βarr-dependent signaling pathway, βarrs link GPCRs to various downstream signaling partners, such as the Raf–mitogen-activated protein kinase extracellular signal–regulated kinase–extracellular signal-regulated kinase cascade. Agonist-stimulated GPCR–βarr complexes have been shown to interact with C-Raf and are thought to initiate the mitogen-activated protein kinase pathway through simple tethering of these signaling partners. However, recent evidence shows that in addition to canonical scaffolding functions, βarrs can allosterically activate downstream targets, such as the nonreceptor tyrosine kinase Src. Here, we demonstrate the direct allosteric activation of C-Raf by GPCR–βarr1 complexes in vitro. Furthermore, we show that βarr1 in complex with a synthetic phosphopeptide mimicking the human V2 vasopressin receptor tail that binds and functionally activates βarrs also allosterically activates C-Raf. We reveal that the interaction between the phosphorylated GPCR C terminus and βarr1 is necessary and sufficient for C-Raf activation. Interestingly, the interaction between βarr1 and C-Raf was considerably reduced in the presence of excess activated H-Ras, a small GTPase known to activate C-Raf, suggesting that H-Ras and βarr1 bind to the same region on C-Raf. Furthermore, we found that βarr1 interacts with the Ras-binding domain of C-Raf. Taken together, these data suggest that in addition to canonical scaffolding functions, GPCR–βarr complexes directly allosterically activate C-Raf by binding to its amino terminus. This work provides novel insights into how βarrs regulate effector molecules to activate downstream signaling pathways.     

Design,synthesis and biological evaluation of novel diosgenin–benzoic acid mustard hybrids with potential anti-proliferative activities in human hepatoma HepG2 cells

To discover new lead compounds with anti-tumour activities, in the present study, natural diosgenin was hybridised with the reported benzoic acid mustard pharmacophore. The in vitro cytotoxicity of the resulting newly synthesised hybrids (8–10, 14a–14f, and 15a–15f) was then evaluated in three tumour cells (HepG2, MCF-7, and HeLa) as well as normal GES-1 cells. Among them, 14f possessed the most potential anti-proliferative activity against HepG2 cells, with an IC₅₀ value of 2.26 µM, which was 14.4-fold higher than that of diosgenin (IC₅₀ = 32.63 µM). Furthermore, it showed weak cytotoxicity against GES-1 cells (IC₅₀ > 100 µM), thus exhibiting good antiproliferative selectivity between normal and tumour cells. Moreover, 14f could induce G0/G1 arrest and apoptosis of HepG2 cells. From a mechanistic perspective, 14f regulated cell cycle-related proteins (CDK2, CDK4, CDK6, cyclin D1 and cyclin E1) as well mitochondrial apoptosis pathway-related proteins (Bax, Bcl-2, caspase 9, and caspase 3). These findings suggested that hybrid 14f serves as a promising anti-hepatoma lead compound that deserves further research.     

γ‐Secretase modulators show selectivity for γ‐secretase–mediated amyloid precursor protein intramembrane processing

The aggregation of β‐amyloid peptide 42 results in the formation of toxic oligomers and plaques, which plays a pivotal role in Alzheimer''s disease pathogenesis. Aβ42 is one of several Aβ peptides, all of Aβ30 to Aβ43 that are produced as a result of γ‐secretase–mediated regulated intramembrane proteolysis of the amyloid precursor protein. γ‐Secretase modulators (GSMs) represent a promising class of Aβ42‐lowering anti‐amyloidogenic compounds for the treatment of AD. Gamma‐secretase modulators change the relative proportion of secreted Aβ peptides, while sparing the γ‐secretase–mediated processing event resulting in the release of the cytoplasmic APP intracellular domain. In this study, we have characterized how GSMs affect the γ‐secretase cleavage of three γ‐secretase substrates, E‐cadherin, ephrin type A receptor 4 (EphA4) and ephrin type B receptor 2 (EphB2), which all are implicated in important contexts of cell signalling. By using a reporter gene assay, we demonstrate that the γ‐secretase–dependent generation of EphA4 and EphB2 intracellular domains is unaffected by GSMs. We also show that γ‐secretase processing of EphA4 and EphB2 results in the release of several Aβ‐like peptides, but that only the production of Aβ‐like proteins from EphA4 is modulated by GSMs, but with an order of magnitude lower potency as compared to Aβ modulation. Collectively, these results suggest that GSMs are selective for γ‐secretase–mediated Aβ production.     

Broussonin A– and B–mediated inhibition of angiogenesis by blockade of VEGFR‐2 signalling pathways and integrin β1 expression

In the present study, we demonstrate the regulatory effects and mechanism of broussonin A and B, diphenylpropane derivatives isolated from Broussonetia kazinoki, on vascular endothelial growth factor‐A (VEGF‐A)–stimulated endothelial cell responses in vitro and microvessel sprouting ex vivo. Treatment with broussonin A or B suppressed VEGF‐A‐stimulated endothelial cell proliferation by regulating the expression of cell cycle–related proteins and the phosphorylation status of retinoblastoma protein. In addition, treatment with broussonin A or B abrogated VEGF‐A‐stimulated angiogenic responses including endothelial cell migration, invasion, tube formation and microvessel formation from rat aortic rings. These anti‐angiogenic activities of broussonin A and B were mediated through inactivation of VEGF‐A‐stimulated downstream signalling pathways, localization of vascular endothelial‐cadherin at cell‐cell contacts, and down‐regulation of integrin β1 and integrin‐liked kinase. Furthermore, treatment with broussonin A or B inhibited proliferation and invasion of non–small cell lung cancer and ovarian cancer cells. Taken together, our findings suggest the pharmacological potential of broussonin A and B in the regulation of angiogenesis, cancer cell growth and progression.     

Transmembrane serine protease 2 (TMPRSS2) proteolytically activates the epithelial sodium channel (ENaC) by cleaving the channel’s γ-subunit

The epithelial sodium channel (ENaC) is a heterotrimer consisting of α-, β-, and γ-subunits. Channel activation requires proteolytic release of inhibitory tracts from the extracellular domains of α-ENaC and γ-ENaC; however, the proteases involved in the removal of the γ-inhibitory tract remain unclear. In several epithelial tissues, ENaC is coexpressed with the transmembrane serine protease 2 (TMPRSS2). Here, we explored the effect of human TMPRSS2 on human αβγ-ENaC heterologously expressed in Xenopus laevis oocytes. We found that coexpression of TMPRSS2 stimulated ENaC-mediated whole-cell currents by approximately threefold, likely because of an increase in average channel open probability. Furthermore, TMPRSS2-dependent ENaC stimulation was not observed using a catalytically inactive TMPRSS2 mutant and was associated with fully cleaved γ-ENaC in the intracellular and cell surface protein fractions. This stimulatory effect of TMPRSS2 on ENaC was partially preserved when inhibiting its proteolytic activity at the cell surface using aprotinin but was abolished when the γ-inhibitory tract remained attached to its binding site following introduction of two cysteine residues (S155C–Q426C) to form a disulfide bridge. In addition, computer simulations and site-directed mutagenesis experiments indicated that TMPRSS2 can cleave γ-ENaC at sites both proximal and distal to the γ-inhibitory tract. This suggests a dual role of TMPRSS2 in the proteolytic release of the γ-inhibitory tract. Finally, we demonstrated that TMPRSS2 knockdown in cultured human airway epithelial cells (H441) reduced baseline proteolytic activation of endogenously expressed ENaC. Thus, we conclude that TMPRSS2 is likely to contribute to proteolytic ENaC activation in epithelial tissues in vivo.     

α–E-catenin binds to dynamitin and regulates dynactin-mediated intracellular traffic

α–Epithelial catenin (E-catenin) is an important cell–cell adhesion protein. In this study, we show that α–E-catenin also regulates intracellular traffic by binding to the dynactin complex component dynamitin. Dynactin-mediated organelle trafficking is increased in α–E-catenin^−/− keratinocytes, an effect that is reversed by expression of exogenous α–E-catenin. Disruption of adherens junctions in low-calcium media does not affect dynactin-mediated traffic, indicating that α–E-catenin regulates traffic independently from its function in cell–cell adhesion. Although neither the integrity of dynactin–dynein complexes nor their association with vesicles is affected by α–E-catenin, α–E-catenin is necessary for the attenuation of microtubule-dependent trafficking by the actin cytoskeleton. Because the actin-binding domain of α–E-catenin is necessary for this regulation, we hypothesize that α–E-catenin functions as a dynamic link between the dynactin complex and actin and, thus, integrates the microtubule and actin cytoskeleton during intracellular trafficking.     

Second generation β-elemene nitric oxide derivatives with reasonable linkers: potential hybrids against malignant brain glioma

Elemene is a second-line broad-spectrum anti-tumour drug that has been used in China for more than two decades. However, its main anti-tumour ingredient, β-elemene, has disadvantages, including excessive lipophilicity and relatively weak anti-tumour efficacy. To improve the anti-tumour activity of β-elemene, based on its minor molecular weight character, we introduced furoxan nitric oxide (NO) donors into the β-elemene structure and designed six series of new generation β-elemene NO donor hybrids. The synthesised compounds could effectively release NO in vitro, displayed significant anti-proliferative effects on U87MG, NCI-H520, and SW620 cell lines. In the orthotopic glioma model, compound Id significantly and continuously suppressed the growth of gliomas in nude mice, and the brain glioma of the treatment group was markedly inhibited (>90%). In short, the structural fusion design of NO donor and β-elemene is a feasible strategy to improve the in vivo anti-tumour activity of β-elemene.     

Novel piperazine–chalcone hybrids and related pyrazoline analogues targeting VEGFR-2 kinase; design,synthesis, molecular docking studies,and anticancer evaluation

New piperazine–chalcone hybrids and related pyrazoline derivatives have been designed and synthesised as potential vascular endothelial growth factor receptor-2 (VEGFR-2) inhibitors. The National Cancer Institute (NCI) has selected six compounds to evaluate their antiproliferative activity in vitro against 60 human cancer cells lines. Preliminary screening of the examined compounds indicated promising anticancer activity against number of cell lines. The enzyme inhibitory activity against VEGFR-2 was evaluated and IC₅₀ of the tested compounds ranged from 0.57 µM to 1.48 µM. The most potent derivatives Vd and Ve were subjected to further investigations. A cell cycle analysis showed that both compounds mainly arrest HCT-116 cell cycle in the G2/M phase. Annexin V-FITC apoptosis assay showed that Vd and Ve induced an approximately 18.7-fold and 21.2-fold total increase in apoptosis compared to the control. Additionally, molecular docking study was performed against VEGFR (PDB ID: 4ASD) using MOE 2015.10 software and Sorafenib as a reference ligand.     

In vitro and in silico studies of bis (indol-3-yl) methane derivatives as potential α-glucosidase and α-amylase inhibitors

In this paper, bis (indol-3-yl) methanes (BIMs) were synthesised and evaluated for their inhibitory activity against α-glucosidase and α-amylase. All synthesised compounds showed potential α-glucosidase and α-amylase inhibitory activities. Compounds 5 g (IC₅₀: 7.54 ± 1.10 μM), 5e (IC₅₀: 9.00 ± 0.97 μM), and 5 h (IC₅₀: 9.57 ± 0.62 μM) presented strongest inhibitory activities against α-glucosidase, that were ∼ 30 times stronger than acarbose. Compounds 5 g (IC₅₀: 32.18 ± 1.66 µM), 5 h (IC₅₀: 31.47 ± 1.42 µM), and 5 s (IC₅₀: 30.91 ± 0.86 µM) showed strongest inhibitory activities towards α-amylase, ∼ 2.5 times stronger than acarbose. The mechanisms and docking simulation of the compounds were also studied. Compounds 5 g and 5 h exhibited bifunctional inhibitory activity against these two enzymes. Furthermore, compounds showed no toxicity against 3T3-L1 cells and HepG2 cells.

Highlights

1. A series of bis (indol-3-yl) methanes (BIMs) were synthesised and evaluated inhibitory activities against α-glucosidase and α-amylase.
2. Compound 5g exhibited promising activity (IC₅₀ = 7.54 ± 1.10 μM) against α-glucosidase.
3. Compound 5s exhibited promising activity (IC₅₀ = 30.91 ± 0.86 μM) against α-amylase.
4. In silico studies were performed to confirm the binding interactions of synthetic compounds with the enzyme active site.

     

Protein Kinase C Activation Upregulates Intercellular Adhesion of α-Catenin–negative Human Colon Cancer Cell Variants via Induction of Desmosomes

The α-catenin molecule links E-cadherin/ β-catenin or E-cadherin/plakoglobin complexes to the actin cytoskeleton. We studied several invasive human colon carcinoma cell lines lacking α-catenin. They showed a solitary and rounded morphotype that correlated with increased invasiveness. These round cell variants acquired a more normal epithelial phenotype upon transfection with an α-catenin expression plasmid, but also upon treatment with the protein kinase C (PKC) activator 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Video registrations showed that the cells started to establish elaborated intercellular junctions within 30 min after addition of TPA. Interestingly, this normalizing TPA effect was not associated with α-catenin induction. Classical and confocal immunofluorescence showed only minor TPA-induced changes in E-cadherin staining. In contrast, desmosomal and tight junctional proteins were dramatically rearranged, with a conversion from cytoplasmic clusters to obvious concentration at cell–cell contacts and exposition at the exterior cell surface. Electron microscopical observations revealed the TPA-induced appearance of typical desmosomal plaques. TPA-restored cell–cell adhesion was E-cadherin dependent as demonstrated by a blocking antibody in a cell aggregation assay. Addition of an antibody against the extracellular part of desmoglein-2 blocked the TPA effect, too. Remarkably, the combination of anti–E-cadherin and anti-desmoglein antibodies synergistically inhibited the TPA effect.

Our studies show that it is possible to bypass the need for normal α-catenin expression to establish tight intercellular adhesion by epithelial cells. Apparently, the underlying mechanism comprises upregulation of desmosomes and tight junctions by activation of the PKC signaling pathway, whereas E-cadherin remains essential for basic cell–cell adhesion, even in the absence of α-catenin.

     

PI3KC2β inactivation stabilizes VE‐cadherin junctions and preserves vascular integrity

Endothelium protection is critical, because of the impact of vascular leakage and edema on pathological conditions such as brain ischemia. Whereas deficiency of class II phosphoinositide 3‐kinase alpha (PI3KC2α) results in an increase in vascular permeability, we uncover a crucial role of the beta isoform (PI3KC2β) in the loss of endothelial barrier integrity following injury. Here, we studied the role of PI3KC2β in endothelial permeability and endosomal trafficking in vitro and in vivo in ischemic stroke. Mice with inactive PI3KC2β showed protection against vascular permeability, edema, cerebral infarction, and deleterious inflammatory response. Loss of PI3KC2β in human cerebral microvascular endothelial cells stabilized homotypic cell–cell junctions by increasing Rab11‐dependent VE‐cadherin recycling. These results identify PI3KC2β as a potential new therapeutic target to prevent aggravating lesions following ischemic stroke.     

MicroRNA‐181a restricts human γδ T cell differentiation by targeting Map3k2 and Notch2

γδ T cells are a conserved population of lymphocytes that contributes to anti‐tumor responses through its overt type 1 inflammatory and cytotoxic properties. We have previously shown that human γδ T cells acquire this profile upon stimulation with IL‐2 or IL‐15, in a differentiation process dependent on MAPK/ERK signaling. Here, we identify microRNA‐181a as a key modulator of human γδ T cell differentiation. We observe that miR‐181a is highly expressed in patients with prostate cancer and that this pattern associates with lower expression of NKG2D, a critical mediator of cancer surveillance. Interestingly, miR‐181a expression negatively correlates with an activated type 1 effector profile obtained from in vitro differentiated γδ T cells and miR‐181a overexpression restricts their levels of NKG2D and TNF‐α. Upon in silico analysis, we identify two miR‐181a candidate targets, Map3k2 and Notch2, which we validate via overexpression coupled with luciferase assays. These results reveal a novel role for miR‐181a as critical regulator of human γδ T cell differentiation and highlight its potential for manipulation of γδ T cells in next‐generation immunotherapies.     

Fatty Acid Esters of Phloridzin Induce Apoptosis of Human Liver Cancer Cells through Altered Gene Expression

Phloridzin (phlorizin or phloretin 2′-O-glucoside) is known for blocking intestinal glucose absorption. We have investigated the anticarcinogenic effect of phloridzin and its novel derivatives using human cancer cell lines. We have synthesised novel acylated derivatives of phloridzin with six different long chain fatty acids by regioselective enzymatic acylation using Candida Antarctica lipase B. The antiproliferative effects of the new compounds were investigated in comparison with the parent compounds, phloridzin, aglycone phloretin, the six free fatty acids and chemotherapeutic drugs (sorafenib, doxorubicin and daunorubicin) using human hepatocellular carcinoma HepG2 cells, human breast adenocarcinoma MDA-MB-231 cells and acute monocytic leukemia THP-1 cells along with normal human and rat hepatocytes. The fatty acid esters of phloridzin inhibited significantly the growth of the two carcinoma and leukemia cells while similar treatment doses were not toxic to normal human or rat hepatocytes. The antiproliferative potency of fatty esters of phloridzin was comparable to the potency of the chemotherapeutic drugs. The fatty acid esters of phloridzin inhibited DNA topoisomerases IIα activity that might induce G₀/G₁ phase arrest, induced apoptosis via activation of caspase-3, and decreased ATP level and mitochondrial membrane potential in HepG2 cells. Based on the high selectivity on cancer cells, decosahexaenoic acid (DHA) ester of phloridzin was selected for gene expression analysis using RT²PCR human cancer drug target array. Antiproliferative effect of DHA ester of phloridzin could be related to the down regulation of anti-apoptotic gene (BCL2), growth factor receptors (EBFR family, IGF1R/IGF2, PDGFR) and its downstream signalling partners (PI3k/AKT/mTOR, Ras/Raf/MAPK), cell cycle machinery (CDKs, TERT, TOP2A, TOP2B) as well as epigenetics regulators (HDACs). These results suggest that fatty esters of phloridzin have potential chemotherapeutic effects mediated through the attenuated expression of several key proteins involved in cell cycle regulation, DNA topoisomerases IIα activity and epigenetic mechanisms followed by cell cycle arrest and apoptosis.     

T cell–derived exosomes induced macrophage inflammatory protein‐1α/β drive the trafficking of CD8+ T cells in oral lichen planus

Oral lichen planus (OLP) is a T cell–mediated chronic inflammatory disease with uncertain aetiology. Exosomes are nanosized particles with biological capacities. Here, we aimed to study the effects of T cell–derived exosomes (T‐exos) on the pathogenesis of OLP and its mechanism. T‐exos were incubated with Jurkat cells for 48 hours, and 26 cytokines in the supernatant were measured by luminex assay. The expression of macrophage inflammatory protein (MIP)‐1α/β was detected using immunohistochemistry and ELISA; that of CCR1/3/5 on peripheral T cells was determined by flow cytometry. Transwell assay was performed to investigate the chemotactic effect of MIP‐1α/β, and cells in the lower chambers were examinated by flow cytometry. As a result, OLP T‐exos elevated the production of MIP‐1α/β, which were highly expressed in OLP tissues and plasma. CCR1/5 were markedly expressed on OLP peripheral T cells, and the majority of CCR1/5⁺ T cells were CD8⁺ T cells. Besides, MIP‐1α/β promoted the migration of OLP mononuclear cells, while inhibiting CCR1/5 significantly decreased the trafficking of mononuclear cells, especially that of CD8⁺ T cells. Conclusively, OLP T‐exos‐induced MIP‐1α/β may drive the trafficking of CD8⁺ T cells after binding with CCR1/5 in OLP, contributing to the development of OLP.