Acute Wounding Alters the Beta2-Adrenergic Signaling and Catecholamine Synthetic Pathways in Keratinocytes

Abstract

Keratinocyte migration is critical for wound re-epithelialization. Previous studies showed that epinephrine activates the beta2-adrenergic receptor (B2AR), impairing keratinocyte migration. Here, we investigated the keratinocyte catecholamine synthetic pathway in response to acute trauma. Cultured keratinocytes were scratch wounded and expression levels of the B2AR and catecholamine synthetic enzymes tyrosine hydroxylase and phenylethanolamine-N-methyltransferase were assayed. The binding affinity of the B2AR was measured. Wounding downregulated B2AR, tyrosine hydroxylase, and phenylethanolamine-N-methyltransferase expression, but pre-exposure to timolol, a beta-adrenergic receptor antagonist, delayed this effect. In wounded keratinocytes, B2AR-binding affinity remained depressed even after its expression returned to prewounding levels. Keratinocyte-derived norepinephrine increased after wounding. Norepinephrine impaired keratinocyte migration; this effect was abrogated with B2AR-selective antagonist ICI-118,551 but not with B1AR-selective antagonist bisoprolol. Finally, for clinical relevance, we determined that norepinephrine was present in freshly wounded skin, thus providing a potential mechanism for impaired healing by local B2AR activation in wound-edge keratinocytes. Taken together, the data show that keratinocytes modulate catecholamine synthetic enzymes and release norepinephrine after scratch wounding. Norepinephrine appears to be a stress-related mediator that impairs keratinocyte migration through activation of the B2AR. Future therapeutic strategies evaluating modulation of norepinephrine-related effects in the wound are warranted.

Systems biology of facial development: contributions of ectoderm and mesenchyme

“…Th and Ddc in the catecholamine pathway were strongly expressed at E10.5. Catecholamines (CA) are synthesized by keratinocytes in response to wounding and CA signaling modulates wound healing (Schallreuter et al, 1995; Sivamani et al, 2014), but neither has previously been implicated in epidermal development. Two components of the Hippo signaling pathway, Amot and Vgll2, were also included in this early program.…”

Combination therapy of autologous adipose mesenchymal stem cell-enriched, high-density lipoaspirate and topical timolol for healing chronic wounds

“…We hypothesized that factors within the chronic wound site, including Staphylococcus aureus and woundgenerated EPI (Sivamani et al, 2014) might induce the AMSC to release inflammatory cytokines and prolong the inflammatory phase, as previously reported in BM-MSC (Dasu et al, 2014). Therefore, we tested whether the beta-adrenergic receptor antagonist, timolol, could reverse the pro-inflammatory phenotype of AMSC that are subjected to these stimuli.…”

“…In addition, AMSC have shown neovascularization and antioxidant potential, which are both essential in the hypoxic-driven milieu of chronic venous leg ulcers (Allen et al, 2013;Fromm-Dornieden and Koenen, 2013;Kim et al, 2007;Nambu et al, 2009;Nie et al, 2011;Park et al, 2008;Sadat et al, 2007). However, AMSC within HDL can assume a pro-inflammatory phenotype, secreting IL-6 and IL-8, when exposed to factors commonly present in a chronic wound, such as Staphylococcus aureus and wound-derived EPI (Sivamani et al, 2014). Timolol, a beta-adrenergic receptor blocker, has been used for decades as a systemic blood pressure lowering agent (Cheng et al, 2012).…”

“…More importantly, AMSC have enhanced wound healing via differentiation and stimulation of neoangiogenesis (Cherubino et al , ; Nie et al ., ; Sadat et al , ). Our group's work with in vitro and animal models of wound healing has demonstrated the impairment of keratinocyte motility (Sivamani et al , ), neutrophil trafficking (Kim et al , ) and wound re‐epithelization from local epinephrine (EPI) in wound milieu (Sivamani et al , ) and the potential of beta‐adrenergic blockade, in the form of timolol, to reverse these effects (Sivamani et al , ). Our previous work has also shown that catecholamines cross‐talk with Toll‐like receptors in both human MSC and keratinocytes to contribute to the chronic wound pathology (Dasu et al , ).…”

Differential Response of Dopamine Mediated by β-Adrenergic Receptors in Human Keratinocytes and Macrophages: Potential Implication in Wound Healing

“…Sivamani et al [26] have shown that the catecholamines released in the wound site decrease the keratinocyte migration mediated by ARs. It has also been described that the activation of β 2 -ARs leads to the in vitro and in vivo inhibition of keratinocytes migration [31, 32], and promotes the recruitment of polymorphonuclear cells by delaying the wound-healing process mediated by the increased IL-6 levels [33]. Furthermore, Shome et al [34] suggested that the neurotransmitter dopamine inhibits the VEGF-induced migration of murine mesenchymal progenitor cells to the wound site in vitro.…”