Tranexamic acid may promote melanocores clustering in keratinocytes through upregulation of Rab5b.

Tranexamic acid (TXA) is a promising therapeutic agent in melasma that can act on multiple pathophysiologic mechanisms of melasma. However, it is unclear whether TXA affects melanin in keratinocytes. To explore the effect of TXA on melanocores in keratinocytes. The melanocore-incorporated keratinocytes were constructed by co-incubating normal human epidermal keratinocytes (NHEK) with melanocores. After being treated with TXA, autophagy- and melanin-related protein expressions were detected. Then, transcriptome sequencing was used to compare the genetic changes in melanocore-incorporated keratinocytes before and after TXA treatment and further verified the differentially expressed genes. At the same time, the distribution of melanocores in human keratinocytes was observed by transmission electron microscopy. We found that TXA does not promote melanin degradation in primary keratinocytes by inducing autophagy. Protein transport and intracellular protein transport-related genes were enriched after TXA treatment, and Rab5b was significantly upregulated. Transmission electron microscopy showed that the percentage of melanocores distributed in clusters increased after treatment with TXA, which was reduced after Rab5b silencing. In addition, results suggested that melanocores could colocalize with Rab5b and lysosome-associated membrane protein1 (LAMP1). Our study found that Rab5b may be involved in the melanocore distribution in keratinocytes. TXA may promote the clustering distribution of endocytic melanocores through upregulation of Rab5b, representing a potential mechanism of TXA treatment against melasma.

The multi-targets mechanism of hydroxychloroquine in the treatment of systemic lupus erythematosus based on network pharmacology.

BACKGROUND: Network pharmacology is used with bioinformatic tools to broaden the understanding of drugs' potential targets and the intersections with key genes of particular disease. Here we applied network pharmacology to collect testable hypotheses about the multi-targets mechanism of hydroxychloroquine (HCQ) against systemic lupus erythematosus (SLE). METHODS: Firstly, we predicted the potential targets of HCQ. Secondly, we got the related genes of SLE returned from databases. Thirdly, the intersections of the potential targets (HCQ) and related genes (SLE) were analyzed with gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Finally, we validated our predictions of the potential targets by performing docking studies with HCQ. RESULTS: The results suggest that the efficacy of HCQ against SLE is mainly associated with the targets of cyclin-dependent kinase 2 (CDK2), estrogen receptor alpha (ESR1) and CDK1, which regulate PI3K/Akt/GSK3ß as well as interferon (IFN) signaling pathway. Biological process of the network associated with the three targets is concentrated in the inhibition of immune response, negative regulation of gene expression and regulation of immune system process. Molecular docking analysis proves that hydrogen bonding and π-π stacking are the main forms of interaction. CONCLUSIONS: Our research provides protein targets affected by HCQ in the treatment of SLE. Three key targets (CDK2, ESR1 and CDK1) involving 1766 proteins become the multi-targets mechanism of HCQ in the treatment of SLE. As well, the research also provides a new idea for introducing network pharmacology into the evaluation of the drugs with multi-targets in dermatology.

IGF-1 resist oxidative damage to HaCaT and depigmentation in mice treated with H2O2.

Vitiligo, an acquired pigmentary disorder of the skin, is characterized by a chronic and progressive loss of melanocyte from the epidermis and follicular reservoir. Growth factor of surrounding cells impacted on melanocytes survival. In this study, lower level of IGF-1 in the lesion was found than that in the donor area of vitiligo patients. IGF-1 improved activation of Nrf2, and inhibited ROS generation and endoplasmic reticulum dilation in HaCaT. C57BL/6 mice were treated with 5% H2O2, and combined with 50 µg/kg of IGF-1 pre-treatment or not once every day for 50 consecutive days. After 50 days, IGF-1 obviously ameliorated depigmentation of mice skin and reduced hair follicle length, skin thickness and Tyrosinase induced by H2O2. Moreover, IGF-1 significantly suppressed CD8+ T cells infiltration in mice skin, inhibited the production of IL-2 and IFN-γ, and decreased the expression of CXCL10 and CXCR3. Thus, the results indicated that IGF-1 could resist oxidative damage to HaCaT, suppress CD8+ T cells infiltration and pro-inflammatory cytokines secretion, and suppresses the thinning of epidermal layer in vivo. It suggests that IGF-1 inhibits oxidative damage to HaCaT and immunosuppressive effects on CD8+ T cells proliferation and activation to resist depigmentation induced by H2O2. This disclosed its multiple roles in the vitiligo, and shed a light on developing the application potential for IGF-1 in vitiligo.

Alterations of Autophagy Modify Lipids in Epidermal Keratinocytes.

Background: The skin barrier is the first line of defense of the body, while skin lipids play an important role in the skin permeability barrier. Lamellar bodies are also involved in maintaining the stability of the skin permeability barrier. However, the exact origin of lamellar bodies remains unclear. Recent studies have suggested that autophagy may participate in the formation of lamellar bodies. Aim: This study aimed to investigate the role of autophagy in the formation of lamellar bodies in keratinocytes and the regulation of keratinocyte lipids. Methods: Keratinocytes were incubated with autophagy inducer Rapamycin and autophagy inhibitor Bafilomycin A1. The changes in autophagy flux were detected by Western blot, and the formation of lamellar bodies was observed by transmission electron microscopy. Furthermore, the changes in keratinocytes lipidomics were detected by liquid chromatography-mass spectrometry. Results: Our research showed that the autophagy inducer promoted autophagy activation and formation of lamellar bodies in keratinocytes, while the inhibitor inhibited autophagy signals and the formation of lamellar bodies in keratinocytes. In addition, the lipidomics results revealed a significant change in glycerophospholipids after autophagy induction and autophagy inhibition. Conclusion: These results demonstrate that autophagy may play an essential role in skin lipids via glycerophospholipids pathway.

Targets of hydroxychloroquine in the treatment of rheumatoid arthritis. A network pharmacology study.

OBJECTIVE: This study was performed to investigate the multi-targets mechanism of hydroxychloroquine (HCQ) in the treatment of rheumatoid arthritis (RA). METHODS: The predicted targets of HCQ and the proteins related to RA were returned from databases. Followed by protein-protein interaction (PPI) network, the intersection of the two group of proteins was studied. Furthermore, gene ontology (GO) and KyotoEncyclopediaofGenesandGenomes (KEGG) enrichment was used to analyse these proteins in a macro perspective. Finally, the candidate targets were checked by molecular docking. RESULTS: The results suggested that HCQ in the treatment of RA was mainly associated with 4 targets that are smoothened homolog (SMO), sphingosine kinase (SPHK) 1, SPHK2 and gatty-acid amide hydrolase (FAAH), with their related 3276 proteins' network which regulate ErbB, HIF-1, NF-κB, FoxO, chemokines, MAPK, PI3K/Akt pathways and so forth. Biological process were mainly focused in the regulation of cell activation, myeloid leukocyte activation, regulated exocytosis and so forth. Molecular docking analysis showed that hydrogen bonding and π-π stacking were the main forms of chemical force. CONCLUSIONS: Our research provides protein targets affected by HCQ in the treatment of RA. SMO, SPHK1, SPHK2 and FAAH involving 3276 proteins become the multi-targets mechanism of HCQ in the treatment of RA.

Induction of cyclic electron flow around photosystem I during heat stress in grape leaves.

Photosystem II (PSII) in plants is susceptible to high temperatures. The cyclic electron flow (CEF) around PSI is thought to protect both PSII and PSI from photodamage. However, the underlying physiological mechanisms of the photosynthetic electron transport process and the role of CEF in grape at high temperatures remain unclear. To investigate this issue, we examined the responses of PSII energy distribution, the P700 redox state and CEF to high temperatures in grape leaves. After exposing 'Cabernet Sauvignon' leaves to various temperatures (25, 30, 35, 40 and 45°C) in the light (600µmol photons m-2s-1) for 4h, the maximum quantum yield of PSII (Fv/Fm) significantly decreased at high temperatures (40 and 45°C), while the maximum photo-oxidizable P700 (Pm) was not affected. As the temperature increased, higher initial rates of increase in post-illumination Chl fluorescence were detected, which were accompanied by an increase in high energy state quenching (qE). The chloroplast NAD(P)H dehydrogenase-dependent CEF (NDH-dependent CEF) activities were different among grape cultivators. 'Gold Finger' with greater susceptibility to photoinhibition, exhibited lower NDH-dependent CEF activities under acute heat stress than a more heat tolerant 'Cabernet Sauvignon'. These results suggest that overclosure of PSII reaction centers at high temperature resulted in the photoinhibition of PSII, while the stimulation of CEF in grape played an important role in the photoprotection of PSII and PSI at high temperatures through contributing to the generation of a proton gradient.