Upregulation of the N-Formyl Peptide Receptors in Scleroderma Fibroblasts Fosters the Switch to Myofibroblasts

Abstract

Systemic sclerosis (SSc) is characterized by chronic inflammation and fibrosis. N-Formyl peptide (fMLF) receptors (FPRs) are chemotactic receptors involved in inflammation. Three FPRs have been identified: FPR1, FPR2, and FPR3. We have examined, by RT-PCR, Western blot and immunohistochemistry, FPRs expression in skin fibroblasts from 10 normal subjects and 10 SSc patients, showing increased expression in SSc fibroblasts. Several functions of FPRs occur through the interaction with a region of the urokinase-type plasminogen activator receptor (uPAR88–92), able to interact with FPRs and to mediate urokinase (uPA) or fMLF-dependent cell migration. Soluble uPAR84–95 peptide can act as a direct ligand of FPRs. Furthermore, uPA or its aminoterminal fragment (ATF) can promote the exposure of the uPAR88–92 region. The WKYMVm peptide is a FPRs pan-agonist. We investigated the functional effects of these agonists on normal and SSc fibroblasts. ATF, uPAR84–95, and WKYMVm regulated adhesion, migration, and proliferation of normal fibroblasts. Despite FPR overexpression, the response of SSc fibroblasts to the same agonists was greatly reduced, except for the proliferative response to ATF. SSc fibroblasts showed increased α-smooth muscle actin expression and improved capability to induce wound closure. Indeed, they overexpressed a cleaved uPAR form, exposing the uPAR88–92 region, and vitronectin, both involved in fibrosis and in the fibroblast-to-myofibroblast transition. FPR stimulation promoted α-smooth muscle actin expression in normal fibroblasts as well as motility, matrix deposition, αvβ5 integrin expression, and radical oxygen species generation in normal and SSc fibroblasts. This study provides evidence that FPRs may play a role in fibrosis and in the fibroblast-to-myofibroblast transition.

Discrimination of Dysplastic Nevi from Common Melanocytic Nevi by Cellular and Molecular Criteria

“…Continued proliferation of nevus cells could explain the relatively larger sizes of DNs compared with CMNs. Our results may also inform on the lamellar fibroplasia observed in DN, as one of the genes upregulated in DNs compared with CMNs, formyl peptide receptor 3 (Table 1B), has recently been implicated in fibrosis (Rossi et al, 2015).…”

HIV-1 Nef promotes migration and chemokine synthesis of human basophils and mast cells through the interaction with CXCR4

“…Figure 2a shows that r-Nef (3–300 ng/ml) (Abcam, Milton, Cambridge, UK) caused a concentration-dependent increase in chemotaxis of purified basophils. In a parallel series of experiments we compared the chemotactic activity of r-Nef with that of CXCL12/SDF-1α (R&D System (Minneapolis, MN) and of the formylated tripeptide N-formyl-methionyl-leucyl-phenylalanine (fMLF) (ICN Biomedicals) potent chemoattractants of human basophils through their interaction with the chemokine receptor CXCR4 and FPR1, respectively [19, 33]. Figure 2b shows that CXCL12/SDF-1α (10 and 100 ng/ml) and fMLF (100 and 500 ng/ml) induced strong chemotaxis of human basophils.…”

“…Similarly, preincubation of basophils with an anti-CXCR4 antibody completely suppressed the chemotactic activity of CXCL12/SDF-1α (100 ng/ml) on these cells. In contrast, the chemotactic effect of fMLF (500 ng/ml), which activates a specific seven-transmembrane receptor independent of the CXCR4 receptor [33, 36], was not affected by the anti-CXCR4 antibody.

Fig. 3Effect of preincubation with anti-CXCR4 and anti-CCR3 antibody on r-Nef-dependent human basophil chemotaxis a Basophils were incubated with ( grey histogram ) or without ( white histogram ) anti-CXCR4 antibody (5 µg/ml) for 1 h, then loaded into the chemotaxis chamber and allowed to migrate toward the indicated concentrations of r-Nef, CXCL12/SDF-1α and fMLF for 1 h at 37 °C in a humidified incubator with 5% CO 2 .

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“…Basophil and mast cell chemotaxis was performed using a modified Boyden chamber technique as previously described [33]. Briefly, 25 µl of a Ca 2+ -containing buffer or various concentrations of the chemoattractants in the same buffer were placed in triplicate in the lower compartment of a 48-well microchemotaxis chamber (Neuroprobe, Cabin John, MD).…”

miR-483-5p plays a protective role in chronic obstructive pulmonary disease

“…This raises the possibility that fibronectin may play an important role in predicting the clinical outcomes in a cohort of patients with mild-to-moderate COPD. Meanwhile, although smooth muscle and endothelial cells also express this marker, α-SMA is still the most commonly used but not a specific marker for myofibroblasts (38)(39)(40)(41), whose expression is mainly intracellular also in spindle-shaped cells (42). α-SMA-positive cells are increased in the airways of COPD patients (43), which suggests that most α-SMA-positive cells reveal typical expression profile of myofibroblasts being positive for α-SMA, vimentin and negative for desmin (44).…”