Human Cardiac-Derived Adherent Proliferating Cells Reduce Murine Acute Coxsackievirus B3-Induced Myocarditis

BACKGROUND: Under conventional heart failure therapy, inflammatory cardiomyopathy typically has a progressive course, indicating a need for alternative therapeutic strategies to improve long-term outcomes. We recently isolated and identified novel cardiac-derived cells from human cardiac biopsies: cardiac-derived adherent proliferating cells (CAPs). They have similarities with mesenchymal stromal cells, which are known for their anti-apoptotic and immunomodulatory properties. We explored whether CAPs application could be a novel strategy to improve acute Coxsackievirus B3 (CVB3)-induced myocarditis. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate the safety of our approach, we first analyzed the expression of the coxsackie- and adenovirus receptor (CAR) and the co-receptor CD55 on CAPs, which are both required for effective CVB3 infectivity. We could demonstrate that CAPs only minimally express both receptors, which translates to minimal CVB3 copy numbers, and without viral particle release after CVB3 infection. Co-culture of CAPs with CVB3-infected HL-1 cardiomyocytes resulted in a reduction of CVB3-induced HL-1 apoptosis and viral progeny release. In addition, CAPs reduced CD4 and CD8 T cell proliferation. All CAPs-mediated protective effects were nitric oxide- and interleukin-10-dependent and required interferon-γ. In an acute murine model of CVB3-induced myocarditis, application of CAPs led to a decrease of cardiac apoptosis, cardiac CVB3 viral load and improved left ventricular contractility parameters. This was associated with a decline in cardiac mononuclear cell activity, an increase in T regulatory cells and T cell apoptosis, and an increase in left ventricular interleukin-10 and interferon-γ mRNA expression. CONCLUSIONS: We conclude that CAPs are a unique type of cardiac-derived cells and promising tools to improve acute CVB3-induced myocarditis

TGF-{beta}1 and laminin-111 cooperate in the induction of IL-16 expression in synovial fibroblasts from rheumatoid arthritis patients

OBJECTIVES: In synovial tissues of rheumatoid arthritis (RA) patients strong expression of laminins and integrins co-localizes with elevated expression of inflammatory cytokines. Synovial fibroblasts (SF) contribute to the pathogenesis of RA through elevated expression of cytokines and chemoattractant factors, one of which is IL-16. We therefore investigated regulatory pathways of IL-16 in SF from RA and osteoarthritis (OA) patients. METHODS: SF were seeded in laminin-coated flasks and activated by the addition of cytokines. Expression of IL-16 was investigated by quantitative RT-PCR, immunoblotting, and ELISA; its biological activity was determined by a cell migration assay. Cell - matrix interactions were investigated by cell binding and attachment assays. Relevant intracellular signaling pathways were studied by immunoblotting and with pharmacological blocking reagents. RESULTS: The stimulation of SF with TGF-beta1 and growth on laminin-111 (LM-111) significantly increased the expression of IL-16. In RA-SF, binding to LM-111 induced significantly more IL-16 mRNA than in OA-SF (p<0.05). The IL-16 cytokine was detected in supernatants of TGF-beta1-activated and in LM-111 plus TGF-beta1-activated RA-SF (38 to 62 pg/ml), but not in supernatants of OA-SF. This IL-16 regulation involved p38MAPK, ERK1/2 and SMAD2 signaling, but not NFkappaB. CONCLUSIONS: Binding of RA-SF to LM-111 in the presence of TGF-beta1 triggers a significant IL-16 response and thus may contribute to the infiltration of CD4+ lymphocytes into synovial tissues. This mode of IL-16 induction represents a novel pathway leading to IL-16 production in RA-SF but not in OA-SF, and it operates independently of NFkappaB signaling