Normal human fibroblasts express pattern recognition receptors for fungal (1-->3)-beta-D-glucans

Area of Science:

• Immunology
• Dermatology
• Molecular Biology

Background:

• Fungal cell wall glucans are known innate immunity stimulants, primarily acting through immune cells like macrophages, neutrophils, and NK cells.
• The existence of glucan receptors on non-immune cells has not been previously reported.
• Understanding fungal-host interactions is crucial for developing novel therapeutic strategies.

Purpose of the Study:

• To investigate the presence and characteristics of glucan binding sites on normal human dermal fibroblasts (NHDF).
• To determine if glucans can modulate the functional activity of NHDF.
• To explore the implications of glucan-fibroblast interactions in host-fungal recognition.

Main Methods:

• Primary cultures of normal human dermal fibroblasts (NHDF) were used.
• Saturable binding assays were performed to quantify glucan binding.
• Competition studies with glucan phosphate and laminarin were conducted.
• NF-kappaB nuclear binding activity and IL-6 gene expression were measured.

Main Results:

• NHDF membranes showed saturable binding of a water-soluble glucan with a dissociation constant (K(D)) of 8.9 μg/ml.
• Competition studies indicated at least two distinct glucan binding sites on NHDF.
• Glucan stimulation led to time-dependent activation of NF-kappaB and increased IL-6 mRNA levels in fibroblasts.
• This study is the first to report glucan binding sites and functional modulation on human fibroblasts.

Conclusions:

• Human dermal fibroblasts possess pattern recognition receptors for fungal (1-->3)-beta-D-glucans.
• Glucans can directly influence the functional activity of fibroblasts, suggesting a broader role in host-fungal interactions.
• These findings expand the understanding of host recognition of fungal components beyond the immune system.