The Phytochemical Shikonin Stimulates Epithelial-Mesenchymal Transition (EMT) in Skin Wound Healing

Abstract

Although various pharmacological activities of the shikonins have been documented, understanding the hierarchical regulation of these diverse bioactivities at the genome level is unsubstantiated. In this study, through cross examination between transcriptome and microRNA array analyses, we predicted that topical treatment of shikonin in vivo affects epithelial-mesenchymal transition (EMT) and the expression of related microRNAs, including 200a, 200b, 200c, 141, 205, and 429 microRNAs, in mouse skin tissues. In situ immunohistological analyses further demonstrated that specific EMT regulatory molecules are enhanced in shikonin-treated epidermal tissues. RT-PCR analyses subsequently confirmed that shikonin treatment downregulated expression of microRNA-205 and other members of the 200 family microRNAs. Further, expression of two RNA targets of the 200 family microRNAs in EMT regulation, Sip1 (Zeb2) and Tcf8 (Zeb1), was consistently upregulated by shikonin treatment. Enhancement of these EMT activities was also detected in shikonin-treated wounds, which repaired faster than controls. These results suggest that topical treatment with shikonin can confer a potent stimulatory effect on EMT and suppress the expression of the associated microRNAs in skin wound healing. Collectively, these cellular and molecular data provide further evidence in support of our previous findings on the specific pharmacological effects of shikonin in wound healing and immune modulation.

Two new dimeric naphthoquinones with neuraminidase inhibitory activity fromLithospermum erythrorhizon

“…The red pigments from the roots of L. erythrorhizon have been used since ancient times as dyestuffs for fabrics, cosmetics and food (Chang et al 2008), and as crude drugs for anti-inflammatory ointment (Ito et al 2011). It exhibits biological activities such as wound healing (Yin et al 2013), antioxidant (Weng et al 2000), antifungal and antitumour (Han et al 2008;Yang et al 2009;Lu et al 2011;Andujar et al 2013). Previous phytochemical studies reported that the red pigments of L. erythrorhizon were mainly composed of naphthoquinone compounds, such as b-hydroxyisovalerylshikonin, acetylshikonin (Gwon et al 2012), propionylshikonin (Cho et al 1999), isobutyrylshikonin (Syklowska-Baranek et al 2012), b,b-dimethylacryloylshikonin (Li et al 2012, isovalerylshikonin, isobutyrylshikonin (Zhao et al 2011) and a-methylbutyrylshikonin.…”

Molecular basis of shikonin-induced immunogenic cell death: insights for developing cancer therapeutics

“…Recently, we also observed that topical treatment of mouse skin with SK conferred a potent stimulatory effect on EMT activity and effectively suppressed the expression of associated microRNAs (200 family microRNAs) during the subsequent skin wound-healing activity [5] . In normal somatic tissues, epithelial-to-mesenchymal transition (EMT) activity is not only instrumental in facilitating wound-healing activity but also in promoting tissue fibrosis [30][31][32] .…”

“…On the other hand, topical treatment with SK was found to also confer a potent stimulatory effect on EMT and many pro-inflammatory activities, such as the increase in expression of MMP2, MMP-9 and vimentin, during wound-healing of skin tissues [5] . These results indicate that SK may exhibit both pro-and anti-inflammatory activities at the tissue/organ levels.…”

“…We suggest that by targeting hnRNPA1 activity via binding with SK the splicing and nuclear export activities of specific inflammation-related genes may be efficiently, but transiently, suppressed, and this highly temporal action may result in an interruption of the acute "cytokine storm", effecting timely control of the "resolution" of inflammation activities. On the other hand, the interaction between SK and hnRNPA1 molecules may also negatively regulate the control of specific tissue wound-healing processes, such as regulation of the expression of 200 family microRNAs [5] . These seemingly contradictory bioactivities of SK at the tissue and organ levels may hence represent an elegant control at the temporal and spatial levels of the proversus anti-inflammatory activities evolved in various mammalian systems, including humans.…”

“…In our previous studies, we showed that SK can confer a broad spectrum of specific cellular and biochemical activities. These include the inhibition of promoter/transcriptional activities of the pro-inflammatory cytokines TNF-á [2] and GM-CSF [3] , the blockade of splicing of TNF-a pre-mRNA [4] , the induction of epithelial-to-mesenchymal transition (EMT) activity in skin wound-healing [5] , and a differential effect on the genomic expression of cytokine/chemokine genes in…”