KCa1.1 and Kv1.3 channels regulate the interactions between fibroblast-like synoviocytes and T lymphocytes during rheumatoid arthritis

Abstract

BackgroundFibroblast-like synoviocytes (FLS) and CCR7− effector memory T (TEM) cells are two of the major cell types implicated in the progression of rheumatoid arthritis (RA). In particular, FLS become highly invasive, whereas TEM cells proliferate and secrete proinflammatory cytokines, during RA. FLS and T cells may also interact and influence each other’s phenotypes. Inhibition of the pathogenic phenotypes of both FLS and TEM cells can be accomplished by selectively blocking the predominant potassium channels that they upregulate during RA: KCa1.1 (BK, Slo1, MaxiK, KCNMA1) upregulated by FLS and Kv1.3 (KCNA3) upregulated by activated TEM cells. In this study, we investigated the roles of KCa1.1 and Kv1.3 in regulating the interactions between FLS and TEM cells and determined if combination therapies of KCa1.1- and Kv1.3-selective blockers are more efficacious than monotherapies in ameliorating disease in rat models of RA.MethodsWe used in vitro functional assays to assess the effects of selective KCa1.1 and Kv1.3 channel inhibitors on the interactions of FLS isolated from rats with collagen-induced arthritis (CIA) with syngeneic TEM cells. We also used flow cytometric analyses to determine the effects of KCa1.1 blockers on the expression of proteins used for antigen presentation on CIA-FLS. Finally, we used the CIA and pristane-induced arthritis models to determine the efficacy of combinatorial therapies of KCa1.1 and Kv1.3 blockers in reducing disease severity compared with monotherapies.ResultsWe show that the interactions of FLS from rats with CIA and of rat TEM cells are regulated by KCa1.1 and Kv1.3. Inhibiting KCa1.1 on FLS reduces the ability of FLS to stimulate TEM cell proliferation and migration, and inhibiting Kv1.3 on TEM cells reduces TEM cells’ ability to enhance FLS expression of KCa1.1 and major histocompatibility complex class II protein, as well as stimulates their invasion. Furthermore, we show that combination therapies of selective KCa1.1 and Kv1.3 blockers are more efficacious than monotherapies at reducing signs of disease in two rat models of RA.ConclusionsOur results demonstrate the importance of KCa1.1 and Kv1.3 in regulating FLS and TEM cells during RA, as well as the value of combined therapies targeting both of these cell types to treat RA.Electronic supplementary materialThe online version of this article (10.1186/s13075-018-1783-9) contains supplementary material, which is available to authorized users.

Pro-inflammatory Cytokines Drive Deregulation of Potassium Channel Expression in Primary Synovial Fibroblasts

“…Our transcriptome analysis demonstrated that pathways were activated in common with arthritis movement of cells, proliferation and both RA and OA. In an in vitro model of RA, Tanner et al (2019) also showed up regulation of Kcnma1 (message and protein) analogous to that observed with our 72 h cytokine treatment. Furthermore, more recent data suggests a correlation between FLS invasiveness and expression of the β-subunit (KCNMB3) in human samples of FLS from RA patients (Petho et al, 2016).…”

“…Typically, Ca 2+ -activated channels couple with Ca 2+ entry channels such as transient receptor potential (TRP) channels; they are both activated by the Ca 2+ ions that enter and maintain the membrane potential hyperpolarized to "draw in" further Ca 2+ . In FLS, Ca 2+ -activated potassium channels appear to drive invasiveness of synoviocytes and progression of arthritis in both human and rodent RA models (Petho et al, 2016;Tanner et al, 2019), by increasing production of both inflammatory mediators and catabolic enzymes (Hu et al, 2012;Friebel et al, 2014;Tanner et al, 2015). This is a paradoxical effect for a potassium conductance, that would be predicted to hyperpolarize cells and reduce migration, proliferation and activity in general.…”

Genome wide analysis of gene expression changes in skin from patients with type 2 diabetes

“…This gene encodes the calcium-and voltage-dependent potassium channel KCa1.1. This channel has been implicated in rheumatoid arthritis, the regulation of integrins, and myoblast function [114][115][116]. We also found decreases in expression for the genes for striatin (STRN) and calmodulin 2 (CALM2).…”

Antioxidant Carbon Nanoparticles Inhibit Fibroblast-Like Synoviocyte Invasiveness and Reduce Disease Severity in a Rat Model of Rheumatoid Arthritis

“…To quantify T lymphocytes, inguinal and popliteal lymph nodes were collected from PIA rats after cardiac perfusion and euthanasia and single cell suspensions were prepared using cell strainers (70 µm). Cells were stained with a panel of antibodies as described [ 37 ], in which the cells were washed with flow cytometry buffer before staining with allophycocyanin-conjugated anti-rat CD3 antibodies (Becton Dickinson, 557030), phycoerythrin-cyanine-7-conjugated anti-rat CD4 antibodies (Biolegend, 201516), phycoerythrin-conjugated anti-rat CD8 antibodies (Becton Dickinson, 554857), fluorescein isothiocyanate-conjugated anti-rat CD25 antibodies (Becton Dickinson, 554865), and biotin-conjugated anti-rat CD45RC antibodies (Invitrogen, MA5-17458), followed by Alexa Fluor 405-conjugated streptavidin (Invitrogen, S32351). Cell fluorescence was measured by flow cytometry, as described above.…”