The Emerging Role of Mast Cells in Response to Fungal Infection

Abstract

Mast cells (MCs) have been considered as the core effector cells of allergic diseases. However, there are evidence suggesting that MCs are involved in the mechanisms of fungal infection. MCs are mostly located in the border between host and environment and thus may have easy contact with the external environmental pathogens. These cells express receptors which can recognize pathogen-associated molecular patterns such as Toll-like receptors (TLR2/4) and C-type Lectins receptors (Dectin-1/2). Currently, more and more data indicate that MCs can be interacted with some fungi (Candida albicans, Aspergillus fumigatus and Sporothrix schenckii). It is demonstrated that MCs can enhance immunity through triggered degranulation, secretion of cytokines and chemokines, neutrophil recruitment, or provision of extracellular DNA traps in response to the stimulation by fungi. In contrast, the involvement of MCs in some immune responses may lead to more severe symptoms, such as intestinal barrier function loss, development of allergic bronchial pulmonary aspergillosis and increased area of inflammatory in S. schenckii infection. This suggests that MCs and their relevant signaling pathways are potential treatment regimens to prevent the clinically unwanted consequences. However, it is not yet possible to make definitive statements about the role of MCs during fungal infection and/or pathomechanisms of fungal diseases. In our article, we aim to review the function of MCs in fungal infections from molecular mechanism to signaling pathways, and illustrate the role of MCs in some common host-fungi interactions.

Fungal Colonization and Infections—Interactions with Other Human Diseases

“…Innate activation through Dectin-1/CARD9 facilitating IL-1β, IL-6, and IL-23 secretion by dendritic cells is critical for disseminating adaptive antifungal Th17-cell responses [31]. A deficiency of Dectin-1 increases the risk of infectious diseases and thus reflects its pivotal role in immune defense [154].…”

“…These events induce the assembly of a scaffold comprising of caspase-recruitment domain 9 (CARD9), adaptor-protein B-cell lymophoma-10 (Bcl-10) and mucosa-associated lymphoid-tissue-lymphoma-translocation protein 1 (MALT1) [27][28][29]. The assembly and activation of the CARD9/Bcl-10/MALT1 complex activates the canonical NF-κB pathway leading to the release of various proinflammatory cytokines and reactive oxygen species (ROS) production, thereby triggering phagocytosis (Figure 1) [30,31].…”

Intestinal strictures in Crohn’s disease: a 2021 update

“…gastrointestinal tract), are the first defense cells to interact with allergens, invading pathogens and other dangerous antigens. 12 , 13 Substantial evidence showed that MCs played a crucial role in fibrotic diseases. 14 However, their explicit effects on CD fibrosis remain unknown.…”

Do Mast Cells Contribute to the Antifungal Host Defense?

“…Among PRRs expressed on MCs, there are also molecules from the CLR group or some TLRs, which may sense different fungal components (Figure 2) [30]. However, little information exists concerning MC involvement in antifungal host defense, and the function of MCs in fungal infections is not precisely defined [31,32].…”