Expression of acidic fibroblast growth factor and basic fibroblast growth factor in nasal polyps

Profibrotic transforming growth factor beta 1 and activin A are increased in nasal polyp tissue and induced in nasal polyp epithelium by cigarette smoke and Toll-like receptor 3 ligation

BACKGROUND

The mechanism of airway remodeling in chronic rhinosinusitis with nasal polyposis (CRSwNP) remains unknown. We wished to determine whether profibrotic transforming growth factor beta 1 (TGF-β1) and activin A and their downstream signaling proteins are increased in CRSwNP and if they are regulated in epithelial cells by noxious or inflammatory stimuli.

METHODS

Frozen tissue from CRSwNP patients, healthy control (HC) middle turbinates, and sinus tissue from CRS without NP (CRSsNP) patients were immunostained for TGF-β1, activin A, and downstream signaling proteins. Primary nasal epithelial cells (PNECs) from HCs and CRSwNP patients were cultured in media, cigarette smoke extract (CSE), or double-stranded RNA (dsRNA) (a ligand for Toll-like receptor-3) and examined for inflammatory and profibrotic genes using real-time polymerase chain reaction (PCR).

RESULTS

CRSwNP patients showed increased TGF-β1 and activin A in the stroma, increased TGF-β1 signaling (phosphorylated Smad2/3) in the stroma and epithelium, and increased Smad3-dependent Snail1 in the stroma. Immunostaining for TGF-β1, pSmad2/3, and Snail1 in CRSwNP patients was highly correlated. Immunostaining for pSmad2/3 and Snail1 was similar in CRSwNP and CRSsNP patients. Compared to HCs, PNECs from CRSwNP patients were more responsive to CSE and dsRNA in terms of TGF-β1 and activin A and more strongly induced by dsRNA in terms of chemokines.

CONCLUSION

Increased TGF-β1 and activin A and increased downstream TGF-β1 signaling is present in CRSwNP patients, primarily in the stroma. This may contribute to features of airway remodeling previously described. PNECs from CRSwNP patients are induced to produce TGF-β1 and activin A by CSE and dsRNA, suggesting that cigarette smoke and viral infection might also contribute to airway remodeling.

Vitamin D3 as a novel regulator of basic fibroblast growth factor in chronic rhinosinusitis with nasal polyposis

BACKGROUND

The immunopathogenesis of chronic rhinosinusitis (CRS) is largely unknown, but it is thought that different inflammatory profiles are responsible for the different CRS subtypes. 25-Hydroxyvitamin-D (25-VD3) has been shown to alter inflammatory mediators in other disease processes and 25-VD3 deficiency is associated with CRS with nasal polyps (CRSwNP), but it is unknown if 25-VD3 levels impact local inflammation in CRS. This study investigated the correlation between plasma 25-VD3 and sinonasal mucus monocyte chemoattractant protein-1 (MCP-1), regulated upon activation normal T cell expressed and secreted (RANTES), and basic fibroblast growth factor (bFGF) levels in patients with CRS.

METHODS

Study subjects undergoing endoscopic sinus surgery (ESS) for CRS were prospectively enrolled from January 2012 to August 2014. Control subjects included patients undergoing ESS for noninflammatory pathology. Blood and sinonasal mucus were collected at the time of ESS. Plasma 25-VD3 was measured by enzyme-linked immunosorbent assay (ELISA) and mucus levels of MCP-1, RANTES, and bFGF by cytometric bead array (CBA).

RESULTS

A total of 57 patients were enrolled and categorized as CRS without nasal polyps (CRSsNP) (n = 31), CRSwNP (n = 14), and controls (n = 12). No significant correlation was found between MCP-1 and 25-VD3. There was a significant negative correlation between 25-VD3 and RANTES (r = -0.612; p = 0.026) and bFGF (r = -0.578; p = 0.039) in CRSwNP patients; however, there was no significant correlation in CRSsNP patients.

CONCLUSION

This data suggests that 25-VD3 may play a role in regulation of RANTES and bFGF expression in CRSwNP. This may occur through regulation of NP fibroblasts or other immune cells. Further investigation is warranted to better elucidate the role of RANTES, bFGF, and 25-VD3 in CRSwNP.

Damage-associated molecular patterns and their receptors in upper airway pathologies

Inflammation of the nasal (rhinitis) and sinus mucosa (sinusitis) are prevalent medical conditions of the upper airways that are concurrent in many patients; hence the terminology "rhinosinusitis". The disease status is further defined to be "chronic" in case symptoms persist for more than 12 weeks without resolution. A diverse spectrum of external factors including viral and bacterial insults together with epithelial barrier malfunctions could be implicated in the chronicity of the inflammatory responses in chronic rhinosinusitis (CRS). However, despite massive research efforts in an attempt to unveil the pathophysiology, the exact reason for a lack of resolution still remains poorly understood. A novel set of molecules that could be implicated in sustaining the inflammatory reaction may be found within the host itself. Indeed, besides mediators of inflammation originating from outside, some endogenous intracellular and/or extracellular matrix (ECM) components from the host can be released into the extracellular space upon damage induced during the initial inflammatory reaction where they gain functions distinct from those during normal physiology. These "host-self" molecules are known to modulate inflammatory responses under pathological conditions, potentially preventing resolution and contributing to the development of chronic inflammation. These molecules are collectively classified as damage-associated molecular patterns (DAMPs). This review summarizes the current knowledge regarding DAMPs in upper airway pathologies, also covering those that were previously investigated for their intracellular and/or ECM functions often acting as an antimicrobial agent or implicated in tissue/cell homeostasis, and for which their function as a danger signaling molecule was not assessed. It is, however, of importance to assess these molecules again from a point of view as a DAMP in order to further unravel the pathogenesis of CRS.

Acidic fibroblast growth factor (FGF) potentiates glial-mediated neurotoxicity by activating FGFR2 IIIb protein

Previous studies indicate that astrocytes are the brain cells that express acidic fibroblast growth factor (aFGF) and that the expression is increased upon activation. However, there has been no study investigating the significance of this phenomenon. Here we report that aFGF treatment of IFNγ-stimulated human astrocytes, and LPS/IFNγ-stimulated human microglia, enhances their secretion of inflammatory cytokines and other materials toxic to human neuroblastoma SH-SY5Y cells. The mechanism of aFGF enhancement involves stimulation of the receptor FGFR2 IIIb. We show by RT-PCR that this receptor, but not other FGF receptors, is robustly expressed by astrocytes and microglia. We establish by Western blotting, and immunohistochemistry on postmortem human brain tissue that the FGFR2 IIIb protein is expressed by both of these glial cell types. We blocked the inflammatory stimulant action of aFGF by transfecting microglia and astrocytes with a small inhibitory RNA (siRNA) to FGFR2 IIIb as well as by removal of aFGF using an anti-aFGF antibody. Treatment with bFGF in combination with the stimulants was without effect, but together with aFGF, it partially counteracted the action of aFGF, indicating that it may be a weak antagonist of FGFR2 IIIb. The inflammatory effect was also attenuated by treatment with inhibitors of protein kinase C, Src tyrosine kinase, and MEK-1/2 indicating the involvement of these intracellular pathways. Our data suggest that inhibition of expression or release of aFGF could have therapeutic potential by inhibiting inflammation in neurodegenerative diseases such as Alzheimer disease where many neuroinflammatory molecules are prominently expressed.

Improved refractory wound healing with administration of acidic fibroblast growth factor in diabetic rats

The aim of the present study is to investigate the effect and mechanism of acidic fibroblast growth factor (aFGF) on treating refractory wound of diabetic rats. SD rats were randomly divided into control group, diabetes group, and aFGF group. Ulcer skin tissues of three groups of rats were respectively collected on days 7 and 14 after establishment of ulcer model for biochemical test, pathological section and immunohistochemistry to comprehensively evaluate the treatment effect of aFGF on diabetic ulcer. The results showed that aFGF could significantly increase capillaries and fibroblast amounts of ulcer tissues, enhance the expression of TGF-β and PCNA proliferation proteins, and thus improved diabetic ulcer tissues. The preliminary mechanism that aFGF helps to promote healing of diabetic ulcer is possibly associated with that aFGF stimulated ulcer skins to secrete TGF-β and PCNA proteins and promoted proliferation of capillaries and fibroblasts.