Exosome-Mediated Crosstalk between Keratinocytes and Macrophages in Cutaneous Wound Healing

Abstract

Bidirectional cell-cell communication involving exosome-borne cargo such as miRNA, has emerged as a critical mechanism for wound healing. Unlike other shedding vesicles, exosomes selectively package miRNA by SUMOylation of heterogeneous nuclear ribonucleoproteinA2B1 (hnRNPA2B1). In this work, we elucidate the significance of exosome in keratinocyte-macrophage crosstalk following injury. Keratinocyte-derived exosomes were genetically labeled with GFP reporter (Exo κ-GFP ) using tissue nanotransfection and were isolated from dorsal murine skin and wound-edge tissue by affinity selection using magnetic beads. Surface N-glycans of Exo κ-GFP were also characterized. Unlike skin exosome, wound-edge Exo κ-GFP demonstrated characteristic N-glycan ions with abundance of low base pair RNA and were selectively engulfed by woundmacrophages (ωmϕ) in granulation tissue. In vitro addition of wound-edge Exo κ-GFP to proinflammatory ωmϕ resulted in conversion to a proresolution phenotype. To selectively inhibit miRNA packaging within Exo κ-GFP in vivo, pH-responsive keratinocyte-targeted siRNA-hnRNPA2B1 functionalized lipid nanoparticles (TLNP κ ) were designed with 94.3% encapsulation *

The Immune Functions of Keratinocytes in Skin Wound Healing

“…These exosomes are highly abundant with small RNAs (<100 bp), suggesting they carry miRNAs. Consistent with this, the specific inhibition of miRNA packaging into exosomes resulted in the accumulation and persistence of wound macrophages in the granulation tissue even after wound closure, indicating close crosstalk between keratinocytes and macrophages through exosome-delivered miRNAs [83]. A closer examination of miRNA composition was not performed in this study, but a recent study by Than et al suggests that miRNAs undergo selective sorting into distinct types of EVs in keratinocytes under homeostatic conditions [84].…”

“…A study by Zhou et al shows that exosome secretion is significantly induced after injury [83]. Wound macrophages selectively engulf exosomes derived from the wound-edge keratinocytes due to the specific surface N-glycan on exosomes [83]. These exosomes are highly abundant with small RNAs (<100 bp), suggesting they carry miRNAs.…”

Insights Into Exosomal Non-Coding RNAs Sorting Mechanism and Clinical Application

“…Exosomes from patients with septic shock convey miRNAs and mRNAs related to inflammatory response for intercellular communication ( 103 ). In general, exosomal ncRNAs are essential as a major contributor that regulates delivery and reduces inflammatory response ( 59 ). The ncRNAs content of exosomes could be regulated by the physiological state of cells and may play a role in maintaining tissue homeostasis and synchronizing the functional state of cells.…”

Standardized Methodologies to Utilize Exosome Treatment as Potential Nano Substances in Hearing Loss

“…As previously reported, exosomes are vesicles composed of lipid membranes that are 100 to 200 nm in size; therefore, they have the property of being able to penetrate smallsized membranes [14,15,33]. Known to play an important role in cell-to-cell communication, useful factors can be divided into donor and recipient cells, and can be used to confirm delivery to the recipient cells [34][35][36]. As a strategy to confirm the effect of indirect exosomes, we propose a co-culture method (Figure 1b(ii)).…”