SLC35E1 promotes keratinocyte proliferation in psoriasis by regulating zinc homeostasis.

Keratinocyte hyperproliferation is a key pathogenic factor in psoriasis. However, the mechanisms that regulate keratinocyte hyperproliferation in this condition remain unclear. Here, we found that SLC35E1 was highly expressed in keratinocytes of patients with psoriasis and that Slc35e1-/- mice displayed a less severe imiquimod (IMQ)-induced psoriasis-like phenotype than their wild-type siblings. In addition, SLC35E1 deficiency inhibited keratinocyte proliferation in both mice and cultured cells. On a molecular level, SLC35E1 was found to regulate zinc ion concentrations and subcellular localization, while zinc ion chelation reversed the IMQ-induced psoriatic phenotype in Slc35e1-/- mice. Meanwhile, epidermal zinc ion levels were decreased in patients with psoriasis and zinc ion supplementation alleviated the psoriatic phenotype in an IMQ-induced mouse model of psoriasis. Our results indicated that SLC35E1 can promote keratinocyte proliferation by regulating zinc ion homeostasis and zinc ion supplementation has potential as a therapy for psoriasis.

Amentoflavone enhances osteogenesis of human mesenchymal stem cells through JNK and p38 MAPK pathways.

Amentoflavone is a bioflavonoid found in a variety of traditional Chinese medicines such as Gingko and Selaginella tamariscina. It has been reported that amentoflavone has anti-inflammatory, antioxidant, antiviral and anticancer effects. However, the effect of amentoflavone on osteogenic differentiation of human mesenchymal stem cells (hMSCs) has not been studied. In this study, we aim to explore the effect of amentoflavone on the proliferation and osteogenic differentiation of hMSCs. The results showed that amentoflavone significantly enhanced the proliferation, alkaline phosphatase (ALP) activity and mineralization in hMSCs. Western blot analysis revealed that the expression of runt-related transcription factor 2 and osterix proteins was upregulated in amentoflavone-treated hMSCs. Furthermore, we investigated the possible signaling pathways responsible for osteogenic differentiation of hMSCs by amentoflavone. We found that amentoflavone significantly increased the levels of phosphorylated JNK and p-p38. The amentoflavone-induced increases of ALP and mineralization were significantly diminished when the JNK and p38 MAPK pathways were blocked by selected inhibitors (SP600125, SB203580) in hMSCs. Furthermore, in vivo evidence indicated that amentoflavone protected against the dexamethasone-induced inhibition of osteoblast differentiation in tg(sp7:egfp) zebrafish larvae. Thus, we showed for the first time that amentoflavone improves the osteogenesis of hMSCs through the JNK and p38 MAPK pathway. Amentoflavone may be beneficial in treating bone-related disorders.

Tanshinol stimulates bone formation and attenuates dexamethasone-induced inhibition of osteogenesis in larval zebrafish.

BACKGROUND/OBJECTIVE: Tanshinol is the main active component of Salvia miltiorrhiza Bunge, a significant Traditional Chinese Medicine used to treat cardiovascular disease. We have shown that tanshinol exerts an antiosteoporostic effect via the enhancement of bone formation in vivo and in vitro. However, the mechanism remains unclear. Based on the polyphenol group in the structure of tanshinol, we speculate the protective action on skeletal tissue is related to antioxidative capacity. Our in vitro evidence indicated that tanshinol stimulated osteoblastic differentiation by its antioxidaive capacity. In this study, we aim to further confirm the effect of tanshinol on bone formation and the underlying mechanism in zebrafish in vivo. METHODS: We used a Danio rerio (zebrafish) model, which has a bone formation process similar to humans, and evaluated the relationship between the dose and the effect of tanshinol on bone formation determined using alizarin red S staining or fluorescence intensity analysis in normal and glucocorticoid (GC)-induced inhibition of an osteogenesis model using wild-type zebrafish and cortical bone transgenic zebrafish tg(sp7:egfp). The expression of osteoblast-specific genes and reactive oxygen species (ROS) were tested. RESULTS: Our data showed that dexamethasone exerts a series of consequences, including the inhibition of bone formation, decrease of bone mass, downregulation of expression of osteoblast-specific genes (runx2a, ALP, osteocalcin, and sp7), as well as the accumulation of ROS generation and decreased capacity of antioxidants. Tanshinol showed a protective effect on promoting bone formation and bone mass both in wild-type larval zebrafish and transgenic zebrafish. Furthermore, tanshinol attenuated the inhibition of osteogenesis elicited by oxidative stress in the zebrafish exposed to dexamethasone. CONCLUSION: The present findings suggest that tanshinol prevented decreased osteogenesis in GC-treated larval zebrafish via scavenging ROS and stimulated the expression of osteoblast-specific genes. Tanshinol treatment may be developed as a novel therapeutic approach under recent recognised conditions of GC-induced osteoporosis.