MicroRNA 143-5p regulates alpaca melanocyte migration, proliferation and melanogenesis

MiR-21 regulated hair follicle cycle development in Cashmere goats by targeting FGF18 and SMAD7

Increasing Cashmere production can add value because it is the primary product of Cashmere goats. Recent years, peoples find miRNAs are crucial in regulating the development of hair follicle. Following Solexa sequencing, many miRNAs were distinguishingly expressed in telogen skin samples of goats and sheep in earlier study. But the method through which miR-21 controls the growth of hair follicles is still ambiguous. Bioinformatics analysis was used to predict the target genes of miR-21. The mRNA level of miR-21 in telogen Cashmere goat skins was higher than in anagen, according to the results of qRT-PCR, and the target genes expressed similarly with miR-21. Western blot showed similar trend, the protein expression of FGF18 and SMAD7 were lower in anagen samples. The Dual-Luciferase reporter assay confirmed miRNA-21's relationship with its target gene, and the consequences indicated found FGF18 and SMAD7 have positive correlations with miR-21. Western blot and qRT-PCR distinguished the expression of protein and mRNA in miR-21 and its target genes. According to the consequence, we found that target genes expression was increased by miR-21 in HaCaT cells. This study identified that miR-21 might take part in the development of Cashmere goat's hair follicles by targeting FGF18 and SMAD7.

Mesenchymal stem cell-derived exosomes and skin photoaging: From basic research to practical application

BACKGROUND

Skin photoaging is a condition caused by long-term exposure to ultraviolet irradiation, resulting in a variety of changes in the skin, such as capillary dilation, increased or absent pigmentation, dryness, sagging, and wrinkles. Stem cells possess a remarkable antioxidant capacity and the ability to proliferate, differentiate, and migrate, and their main mode of action is through paracrine secretion, with exosomes being the primary form of secretion. Stem cell-derived exosomes contain a variety of growth factors and cytokines and may have great potential to promote skin repair and delay skin ageing.

METHODS

This review focuses on the mechanisms of UV-induced skin photoaging, the research progress of stem cell exosomes against skin photoaging, emerging application approaches and limitations in the application of exosome therapy.

RESULT

Exosomes derived from various stem cells have the potential to prevent skin photoaging.

CONCLUSION

The combination with novel materials may be a key step for their practical application, which could be an important direction for future basic research and practical applications.

The effects of miRNA-27a-3p on human epidermal melanocytes

OBJECTIVE

To characterize the effects of miRNA-27a-3p on the biological properties of human epidermal melanocytes (MCs).

METHODS

MCs were obtained from human foreskins and transfected with miRNA-27a-3p mimic (induces the overexpression of miRNA-27a-3p), mimic-NC (the negative control group), miRNA-27a-3p inhibitor, or inhibitor-NC. After transfection, the proliferation of MCs in each group was evaluated by cell counting kit-8 (CCK-8) at 1, 3, 5, and 7 days. Twenty-four hours later, the MCs were transferred onto a living cell imaging platform and cultured for another 12 h to detect their trajectories and velocities. On days 3, 4, and 5 after transfection, the expression of melanogenesis-related mRNAs, protein levels, and melanin contents were measured using reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and NaOH solubilization, respectively.

RESULTS

The RT-PCR results showed that miRNA-27a-3p was successfully transfected into MCs. The proliferation of MCs was restrained by miRNA-27a-3p. There were no significant differences in the movement trajectories of MCs in the four transfected groups, but the cell movement velocity in the mimic group was slightly lower; that is, the overexpression of miRNA-27a-3p inhibited the speed of MCs. The expression levels of melanogenesis-related mRNAs and proteins were decreased in the mimic group and were increased in the inhibitor group. Melanin content in the mimic group was lower than that in the other three groups.

CONCLUSIONS

Overexpression of miRNA-27a-3p inhibits the expression of melanogenesis-related mRNAs and proteins, reduces the melanin content of human epidermal MCs, and slightly impacts their movement speed.

RNA-Seq Reveals the Roles of Long Non-Coding RNAs (lncRNAs) in Cashmere Fiber Production Performance of Cashmere Goats in China

Long non-coding RNAs (lncRNAs) are a kind of non-coding RNA being >200 nucleotides in length, and they are found to participate in hair follicle growth and development and wool fiber traits regulation. However, there are limited studies reporting the role of lncRNAs in cashmere fiber production in cashmere goats. In this study, Liaoning cashmere (LC) goats (n = 6) and Ziwuling black (ZB) goats (n = 6) with remarkable divergences in cashmere yield, cashmere fiber diameter, and cashmere color were selected for the construction of expression profiles of lncRNAs in skin tissue using RNA sequencing (RNA-seq). According to our previous report about the expression profiles of mRNAs originated from the same skin tissue as those used in the study, the cis and trans target genes of differentially expressed lncRNAs between the two caprine breeds were screened, resulting in a lncRNA-mRNA network. A total of 129 lncRNAs were differentially expressed in caprine skin tissue samples between LC goats and ZB goats. The presence of 2 cis target genes and 48 trans target genes for the differentially expressed lncRNAs resulted in 2 lncRNA-cis target gene pairs and 93 lncRNA-trans target gene pairs. The target genes concentrated on signaling pathways that were related to fiber follicle development, cashmere fiber diameter, and cashmere fiber color, including PPAR signaling pathway, metabolic pathways, fatty acid metabolism, fatty acid biosynthesis, tyrosine metabolism, and melanogenesis. A lncRNA-mRNA network revealed 22 lncRNA-trans target gene pairs for seven differentially expressed lncRNAs selected, of which 13 trans target genes contributed to regulation of cashmere fiber diameter, while nine trans target genes were responsible for cashmere fiber color. This study brings a clear explanation about the influences of lncRNAs over cashmere fiber traits in cashmere goats.

Identification and Characterization of Circular RNAs (circRNAs) Using RNA-Seq in Two Breeds of Cashmere Goats

Circular RNA (circRNA) is a type of non-coding RNA generated from back-splicing the reactions of linear RNA. It plays an important role in various cellular and biological processes. However, there are few studies about the regulatory effect of circRNAs on cashmere fiber traits in cashmere goats. In this study, the expression profiles of circRNAs in skin tissue were compared between Liaoning cashmere (LC) goats and Ziwuling black (ZB) goats, with a significant difference in cashmere fiber yield, cashmere fiber diameter, and cashmere fiber color, using RNA-seq. A total of 11,613 circRNAs were expressed in the caprine skin tissue, and their type, chromosomal distribution, and length distribution were characterized. A total of 115 up-regulated circRNAs and 146 down-regulated circRNAs in LC goats were screened compared to ZB goats. The authenticity of 10 differentially expressed circRNAs was validated by detecting their expression levels and the head-to-tail splice junction using RT-PCR and DNA sequencing, respectively. The parent genes of differentially expressed circRNA were mainly enriched in some Gene Ontology (GO) terms and pathways related to cashmere fiber traits, such as the canonical Wnt signaling pathway, which is involved in the regulation of cell promotion, stem cell proliferation, Wnt signaling pathway regulation, epithelial morphogenesis, MAPK signaling pathway, and cell adhesion molecules pathway. Eight differentially expressed circRNAs were further selected to construct a circRNA-miRNA network, and some miRNAs that were previously reported as related to fiber traits were found in the network. This study provides a deep understanding of the roles of circRNAs in the regulation of cashmere fiber traits in cashmere goats and the involvement of differential splicing in phenotypic expression according to breed and region.

The Potential of Bovine Colostrum-Derived Exosomes to Repair Aged and Damaged Skin Cells

In this study, we examined the potentially beneficial effects of bovine colostrum-derived exosomes on UV-induced aging and damage in three major resident skin cells including keratinocytes, melanocytes, and fibroblasts. The treatment with colostrum exosomes prevented the UV-induced generation of intracellular reactive oxygen species in epidermal keratinocytes. In UV-stimulated melanocytes, colostrum exosomes could also significantly reduce the production of the protective skin-darkening pigment melanin, which may help to reduce the risk of excessive melanin formation causing skin hyperpigmentation disorders. In the human dermal fibroblasts treated with colostrum exosomes, the expression of matrix metalloproteinases was suppressed, whereas increased cell proliferation was accompanied by enhanced production of collagen, a major extracellular matrix component of skin. Taken together, our findings indicate that bovine colostrum-derived exosomes having excellent structural and functional stability offer great potential as natural therapeutic agents to repair UV-irradiated skin aging and damage.

Role of miRNAs in melanin metabolism: Implications in melanin-related diseases

BACKGROUND

MicroRNAs (miRNAs) are short single-stranded non-coding RNAs that regulate degradation and expression of messenger RNA (mRNA) and play a wide range of key roles in different biological processes. They mediate different stages of melanocyte differentiation, growth, and apoptosis through a variety of pathways and can mediate melanin production by targeting key enzymes.

AIMS

This article was aimed to review the role of miRNAs in melanin metabolism and to introduce the role and significance of miRNAs in melanin-related diseases.

MATERIALS & METHODS

Systematic search and retrospective review were performed on the published data.

RESULTS

This paper reviews the process of melanin synthesis and the regulatory mechanism, explores the miRNA expression profiles in different model organisms, and introduces the mechanisms of several key miRNAs participating in melanin metabolism through target genes. We also explore the potential role of miRNA as a new target for the treatment of melanin metabolism disease, including vitiligo, melanoma, and chloasma.

CONCLUSION

miRNAs play a key role in melanin-related diseases, and the miRNAs involved may be potential therapeutic targets.

The role of KLF4 in melanogenesis and homeostasis in sheep melanocytes

KLF4 expression has been associated with hair color in mammals and has also been found to regulate melanoma cell growth. Here, we assessed the influence of KLF4 on coat color formation and melanocytes. We found that KLF4 was highly expressed in the black skin of sheep both at the mRNA and protein levels compared with white skin. KLF4 immunostaining further showed that KLF4 protein was mainly expressed in epidermal, outer root, and hair bulb regions. In sheep melanocytes, the proliferation of melanocytes was inhibited by KLF4 overexpression and this decrease in cell proliferation was coupled with induction of the S phase, cell cycle arrest, and apoptosis. In vitro cell migration assays showed that KLF4 suppressed cell migration. In addition, KLF4 overexpression significantly increased melanin production and pigment-related gene expression. Collectively, our findings show that KLF4 is important for coat color formation and melanocyte homeostasis.

miR-143 Targeting CUX1 to Regulate Proliferation of Dermal Papilla Cells in Hu Sheep

Wool curvature is the determining factor for lambskin quality of Hu lambs. However, the molecular mechanism of wool curvature formation is not yet known. miRNA has been proved to play an important role in hair follicle development, and we have discovered a differentially expressed miRNA, miR-143, in hair follicles of different curl levels. In this study, we first examined the effects of miR-143 on the proliferation and cell cycle of dermal papilla cells using CCK8, EdU and flow cytometry and showed that miR-143 inhibited the proliferation of dermal papilla cells and slowed down the cell cycle. Bioinformatics analysis was performed to predict the target genes KRT71 and CUX1 of miR-143, and both two genes were expressed at significantly higher levels in small waves than in straight lambskin wool (p < 0.05) as detected by qPCR and Western blot (WB). Then, the target relationships between miR-143 and KRT71 and CUX1 were verified through the dual-luciferase assay in 293T cells. Finally, after overexpression and suppression of miR-143 in dermal papilla cells, the expression trend of CUX1 was contrary to that of miR-143. Meanwhile, KRT71 was not detected because KRT71 was not expressed in dermal papilla cells. Therefore, we speculated that miR-143 can target CUX1 to inhibit the proliferation of dermal papilla cells, while miR-143 can target KRT71 to regulate the growth and development of hair follicles, so as to affect the development of hair follicles and ultimately affect the formation of wool curvature.

Milk Exosome-Derived MicroRNA-2478 Suppresses Melanogenesis through the Akt-GSK3β Pathway

Exosomes participate in intercellular communication by transferring molecules from donor to recipient cells. Exosomes are found in various body fluids, including blood, urine, cerebrospinal fluid and milk. Milk exosomes contain many endogenous microRNA molecules. MicroRNAs are small noncoding RNAs and have important roles in biological processes. The specific biological functions of milk exosomes are not well understood. In this study, we investigated the effects of milk exosomes on melanin production in melanoma cells and melanocytes. We found that milk exosomes decreased melanin contents, tyrosinase activity and the expression of melanogenesis-related genes in melanoma cells and melanocytes. Bovine-specific miR-2478 in exosomes inhibited melanin production. We found that Rap1a is a direct target gene of miR-2478 in melanoma cells and melanocytes. MiR-2478 overexpression decreased Rap1a expression, which led to downregulated melanin production and expression of melanogenesis-related genes. Inhibition of Rap1a expression decreased melanogenesis through the Akt-GSK3β signal pathway. These results support the role of miR-2478 derived from milk exosomes as a regulator of melanogenesis through direct targeting of Rap1a. These results show that milk exosomes could be useful cosmeceutical ingredients to improve whitening.

Effects of keratinocyte-derived and fibroblast-derived exosomes on human epidermal melanocytes

BACKGROUND

Exosomes have been demonstrated to carry proteins, membrane lipids, mRNAs and microRNAs which can be transferred to surrounding cells and regulate the functions of those recipient cells.

OBJECTIVES

The objective of the study was to investigate the effects of exosomes released by keratinocytes and fibroblasts on the proliferation, tyrosinase activity and melanogenesis of melanocytes.

METHODS

Melanocytes, keratinocytes and fibroblasts obtained from human foreskin were cultured and exosomes secreted by keratinocytes and fibroblasts were harvested from the culture supernatants by ultracentrifugation. Each exosome fraction was divided into two parts; one part was subjected to high-throughput sequencing using an Illumina HiSeq sequencer to characterize the microRNA expression profiles, while the other part was labeled with the fluorescent dye PKH67 and was then co-cultivated with epidermal melanocytes.

RESULTS

High-throughput sequencing analysis showed 168 differentially expressed microRNA within exosomes derived from keratinocytes and from fibroblasts, 97 of those being up-regulated with the other 71 down-regulated. Gene ontology analysis showed that the target genes responsible for these differentially expressed microRNAs were mainly enriched in the protein-binding region of molecular functions. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that target genes regulated by differentially expressed microRNA were mainly involved in mitogen-activated protein kinase (MAPK) signaling pathway, Ras signaling pathway, cAMP signaling pathway and Wnt signaling pathway. Keratinocyte-derived exosomes were taken up by melanocytes co-cultured with them and promoted the proliferation, tyrosinase activity and melanin synthesis of those melanocytes. However, fibroblast-derived exosomes had no similar effects on melanocytes.

CONCLUSION

Keratinocyte-derived exosomes but not fibroblast-derived exosomes were taken up by melanocytes in co-culture and significantly stimulated their proliferation, tyrosinase activity and melanin synthesis. Those different effects may be mainly due to the differential expression of microRNAs in exosomes derived from the different types of cells.

LIMITATIONS

Electron microscopy of the obtained exosomes and in-depth study of apparently differentially expressed microRNAs were not performed.

Epigenetic regulation of melanogenesis

Melanogenesis is a complex process in which melanin is synthesized in melanocytes and transported to keratinocytes, which involves multiple genes and signaling pathways. Epigenetics refers to the potential genetic changes that affect gene expression without involving changes in the original sequence of DNA nucleotides. DNA methylation regulates the expression of key genes such as tyrosinase (TYR), tyrosinase-related protein 1 (TYRP1), dopachrome tautomerase (DCT) and microphthalmia-associated transcription factor (MITF), as well as paracrine factors such as stem cell factor (SCF) and endothelin-1 (ET-1) in melanogenesis. Potential DNA methylation sites are present in the genes of melanogenesis-related signaling pathways such as "Wnt", "PI3K/Akt/CREB" and "MAPK". H3K27 acetylation is abundant in melanogenesis-related genes. Both the upstream activation and downstream regulation of MITF depend on histone acetyltransferase CBP/p300, and pH-induced H3K27 acetylation may be the amplifying mechanism of MITF's effect. HDAC1 and HDAC10 catalyze histone deacetylation of melanogenesis-related gene promoters. Chromatin remodelers SWI/SNF complex and ISWI complex use the energy of ATP hydrolysis to rearrange nucleosomes, while their active subunits BRG1, BRM and BPTF, act as activators and cofactors of MITF. MicroRNAs (miRNAs) can directly target a large number of melanogenesis-related genes, while long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) regulate melanogenesis in a variety of ways. Interactions exist among the epigenetic mechanisms of melanogenesis. For example, the methyl CpG binding domain protein 2 (MeCP2) links DNA methylation, histone deacetylation, and histone methylation. Epigenetic-based therapy provides novel opportunities for treating dermatoses that are caused by pigmentation disturbances. This review summarizes the epigenetic regulation mechanisms of melanogenesis, and examines the pathogenesis and treatment of epigenetics in pigmentation disorders.

GNAI2 Promotes Proliferation and Decreases Apoptosis in Rabbit Melanocytes

GNAI2 (G protein subunit alpha i2) is a signaling modulator or transducer, involved in several transmembrane signaling systems, that plays a vital role in the melanogenesis signaling pathway. However, whether GNAI2 regulates cell proliferation and apoptosis in rabbit melanocytes is not known. We found that GNAI2 was differentially expressed in rabbits with different coat colors using qRT-PCR and Wes assays. Furthermore, it was observed that the rabbits with black skin had the highest GNAI2 levels, and those with white skin had the lowest expression. The coding sequence of GNAI2 was successfully cloned and inserted into pcDNA3.1 and pcDNA3.1-Myc vectors. It was observed that the GNAI2 protein was mainly localized in the cytoplasm using the indirect immunofluorescence staining assay. Overexpression of GNAI2 significantly increased melanin content, promoted melanocyte proliferation, and inhibited melanocyte apoptosis. On the contrary, the knockdown of GNAI2 using siRNA had the opposite effect. In addition, GNAI2 significantly increased the mRNA expression levels of the melanin-related genes TYR, GPNMB, PMEL, and DCT in rabbit melanocytes. The results suggested that GNAI2 regulated melanocyte development by promoting melanocyte proliferation and inhibiting apoptosis.

microRNAs in the Regulation of Melanogenesis

Melanogenesis is the process leading to the synthesis of melanin, the main substance that influences skin color and plays a pivotal role against UV damage. Altered melanogenesis is observed in several pigmentation disorders. Melanogenesis occurs in specialized cells called melanocytes, physically and functionally related by means of autocrine and paracrine interplay to other skin cell types. Several external and internal factors control melanin biosynthesis and operate through different intracellular signaling pathways, which finally leads to the regulation of microphthalmia-associated transcription factor (MITF), the key transcription factor involved in melanogenesis and the expression of the main melanogenic enzymes, including TYR, TYRP-1, and TYRP-2. Epigenetic factors, including microRNAs (miRNAs), are involved in melanogenesis regulation. miRNAs are small, single-stranded, non-coding RNAs, of approximately 22 nucleotides in length, which control cell behavior by regulating gene expression, mainly by binding the 3′ untranslated region (3′-UTR) of target mRNAs. This review collects data on the miRNAs involved in melanogenesis and how these miRNAs can modulate target gene expression. Bringing to light the biological function of miRNAs could lead to a wider understanding of epigenetic melanogenesis regulation and its dysregulation. This knowledge may constitute the basis for developing innovative treatment approaches for pigmentation dysregulation.

Expression of miRNA-203 and its target gene in hair follicle cycle development of Cashmere goat

MicroRNA plays an important regulatory role in the development of all organisms, including hair follicle development. In order to improve domestic cashmere yield, the role of miRNA in hair follicle cycle has become a research hotspot. However, the molecular and cellular mechanisms by which miRNA-203 regulates hair follicle development are not completely understood. In this study, we found that the relevant target genes of miRNA-203 (DDOST and NAE1) were less expressed in telogen by qPCR and Immunoblotting analysis, contrary to the expression mode of miRNA-203. The Dual-Luciferase reporter assay was used to verify the correlation between miRNA-203 and its target gene expression. The results showed that miRNA-203 specifically binds to the 3 'UTR of DDOST and NAE1, and the expression of miRNA-203 significantly down-regulates the expression of DDOST and NAE1 mRNA and protein. Therefore, this study demonstrates that miRNA-203 may regulate hair follicle development in Cashmere goats by targeting DDOST and NAE1.

Screening of non-invasive miRNA biomarker candidates for metastasis of gastric cancer by small RNA sequencing of plasma exosomes

Gastric cancer remains one of the most lethal and prevalent malignancies, particularly in China. The majority of patients are diagnosed with gastric cancer at the late stages of the disease. Besides, the high relapse rate also contributes to the high mortality. Therefore, there exists an imperative need for the development of gastric cancer diagnostic techniques as well as novel indicators for gastric cancer metastasis. Exosomes, secreted by a variety of cell types, play critical roles in intercellular communication, which emerge as promising diagnostic biomarkers for gastric cancer. In this study, we present for the first time, at least to the best of our knowledge, the small RNA sequencing spectra of exosomes derived from the gastric cancer patient plasma using next-generation sequencing, focusing on the exploration of metastasis-related biomarkers. The exosomes enriched from patient plasma samples were well characterized by western blotting, transmission electron microscopy and nanoparticle-tracking analysis. In the following bioinformatic analysis of exosomal miRNAs, three candidates were proposed as the biomarkers for metastasis of gastric cancer, namely miR-10b-5p, miR-101-3p and miR-143-5p, for gastric cancer with lymph node metastasis, gastric cancer with ovarian metastasis and gastric cancer with liver metastasis, respectively. RT-qPCR was performed to test the accuracy of these candidates for validation. In conclusion, we successfully isolated and purified exosomes from plasma of patients with gastric cancer and identified several potential exosomal miRNA markers to distinguish gastric cancer patients with various kinds of metastasis.

Insight into Mechanistic Action of Thymoquinone Induced Melanogenesis in Cultured Melanocytes

BACKGROUND

Melanin plays a crucial role in camouflage, social communication and protection against harmful ultraviolet radiations. Melanin is synthesized by melanocytes through melanogenesis and several intrinsic and extrinsic factors are involved during the process. Any change occuring in the normal melanogenesis process can cause severe pigmentation problems of hypopigmentation or hyperpigmentation.

OBJECTIVE

The present study is based on the evaluation of the effect of thymoquinone on melanogenesis and their possible mechanism of action using the B16F10 melanoma cell line for the production via blocking signaling pathways.

METHODS

Phase contrast microscopy, cell viability, tyrosinase activity, melanin content and western blot analysis were used in the present study.

RESULTS

In the present investigation, cultured melanocytes exhibit that the stimulation of melanin synthesis when treated with thymoquinone. Tyrosinase activity and melanin production in B16F10 melanoma cell line was increased in doze-dependent manner. In western blot, we investigated the involvement of the cAMP/PKA pathway in thymoquinone induced melanogenesis. It was observed protein kinase inhibitors PKA, PKC, PKB and MEK1 decreased the stimulatory effects of thymoquinone from 11.45- fold value to 8.312, 6.631, 4.51, and 7.211-fold value, respectively. However, the results also prove that thymoquinone may partially induce tyrosinase expression via PKA, PKB, PKC and MEK1 signaling pathways.

CONCLUSION

The present finding proposed that thymoquinone is a protective challenger for melanogenesis and it might be useful for the treatment of hypopigmentary disorders.

miR-380-3p regulates melanogenesis by targeting SOX6 in melanocytes from alpacas (Vicugna pacos)

BACKGROUND

Melanocytes are derived from neural crest stem cells in the embryonic stage. In mature melanocytes, a series of complex enzyme-catalyzed reactions leads to the production of melanins, which determine the hair and skin colors of animals. The process of melanogenesis is complex and can be regulated by mRNA, microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) genes. MiRNAs are a type of endogenous noncoding RNA approximately 22 nt in size that predominantly regulate gene expression by inhibiting translation. miR-380-3p is a candidate miRNA potentially related to melanogenesis. To better understand the mechanism of miR-380-3p melanogenesis regulation, plasmids to overexpress or knockdown miR-380-3p were transfected into alpaca melanocytes, and their effects on melanogenesis were evaluated.

RESULTS

In situ hybridization identified a positive miR-380-3p signal in alpaca melanocyte cytoplasm. Luciferase activity assays confirmed that SOX6 is targeted by miR-380-3p. miR-380-3p overexpression and knockdown in alpaca melanocytes respectively downregulated and upregulated SOX6 expression at the mRNA and protein levels. Additionally, miR-380-3p overexpression and knockdown, respectively, in alpaca melanocytes decreased and increased the mRNA levels of melanin transfer-related genes, including microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosine-related protein-1 (TYRP1), and dopachrome tautomerase (DCT). In contrast, miR-380-3p overexpression and knockdown respectively increased and decreased the mRNA levels of β-catenin. Additionally, the effect of miR-380-3p on melanogenesis was assessed by Masson-Fontana melanin staining.

CONCLUSIONS

The results demonstrated that miR-380-3p targeted SOX6 to regulate melanogenesis by influencing β-catenin and MITF transcription and translation, which reduced the expression of downstream genes, including TYR, TYRP1, and DCT. These results provide insights into the mechanisms through which miR-380-3p controls melanogenesis.

MiR-27a regulates WNT3A and KITLG expression in Cashmere goats with different coat colors

MicroRNAs(miRNAs) regulate and control gene expression at the post-transcriptional level by base pairing with its target gene 3'UTR, resulting in degradation of the target mRNA or inhibition of its translation. The previous high-throughput sequencing results indicated that miR-27a was involved in coat color regulation. However, the mechanism of action is not still illuminated. In this research, using western blotting and real-time quantitative polymerase chain reaction(qRT-PCR), the expression of miR-27a, WNT3A and KITLG were examined in the skin of Cashmere goats with white and brown, and human embryonic kidney 293 T cells (HEK-293T cells) which over-express miR-27a. Targeting relationship between miR-27a and WNT3A or KITLG was examined by the luciferase reporter gene system. The qRT-PCR detection showed that miR-27a was more highly expressed in white Cashmere goats skin than that in brown Cashmere goats skin. Furthermore, WNT3A and KITLG mRNA and protein expression were down-regulated by miR-27a in vitro and in vivo. A dual-luciferase reporter gene indicated that miR-27a negatively correlates with WNT3A or KITLG. In a word, our research demonstrated that the expression of miR-27a was evidently differential in the white and brown Cashmere goats skin and WNT3A or KITLG was negatively regulated by miR-27a.

Long non-coding RNAs in cutaneous biology and proliferative skin diseases: Advances and perspectives

Advances in transcriptome sequencing have revealed that the genome fraction largely encodes for thousands of non‐coding RNAs. Long non‐coding RNAs (lncRNAs), which are a class of non–protein‐coding RNAs longer than approximately 200 nucleotides in length, are emerging as key epigenetic regulators of gene expression recently. Intensive studies have characterized their crucial roles in cutaneous biology and diseases. In this review, we address the promotive or suppressive effects of lncRNAs on cutaneous physiological processes. Then, we focus on the pathogenic role of dysfunctional lncRNAs in a variety of proliferative skin diseases. These evidences suggest that lncRNAs have indispensable roles in the processes of skin biology. Additionally, lncRNAs might be promising biomarkers and therapeutic targets for cutaneous disorders.

Knockdown of microRNA‑143‑5p by STTM technology affects eumelanin and pheomelanin production in melanocytes

MicroRNAs (miRNAs) serve various roles in the regulation of melanogenesis in mammalian melanocytes that contribute to the development of hair color. The manipulation of the melanocyte action is a new target for genetic improvement. Short tandem target mimic (STTM) is a potent approach for silencing miRNAs in plants and animals. To investigate the function of miR‑143‑5p in melanogenesis, STTM was used to block the expression of miR‑143‑5p (STTM‑miR‑143‑5p). The molecular analysis and luciferase reporter assay identified myosin Va gene (MYO5A) as one of the miR‑143‑5p targets. STTM‑miR‑143‑5p overexpression resulted in an increased expression of downstream melanogenesis genes including microphthalmia‑associated transcription factor (MITF), tyrosinase family members [tyrosinase (TYR) and tyrosinase‑related protein 1 (TYRP1)], melanophilin (MLPH), and Rab27a, thereby contributing to melanocyte pigmentation by promoting total alkali‑soluble melanogenesis (ASM) and eumelanin (EM) contents; conversely, STTM‑miR‑143‑5p overexpression resulted in decreased expression of the tyrosinase‑related protein 2 (TYRP2)/dopachrome tautomerase (DCT), which is responsible for decreased pheomelanin (PM) content in mouse melanocytes. The results indicated that melanin production in melanocytes could be increased by manipulating miR‑143‑5p expression using STTM which resulted in ASM and EM production.

The Long Noncoding RNA UCA1 Negatively Regulates Melanogenesis in Melanocytes

The long noncoding RNA UCA1 was first discovered in bladder cancer and is known to regulate the proliferation and migration of melanoma. However, its role in melanogenesis is unclear. In this study, we aimed to explore the role and mechanism of UCA1 in melanogenesis. Our findings showed that the expression of UCA1 was negatively correlated with melanin content in melanocytes and pigmented nevus. Overexpression of UCA1 in melanocytes decreased melanin content and the expression of melanogenesis-related genes, whereas knockdown of UCA1 in melanocytes had the opposite effect. High-throughput sequencing revealed that microphthalmia-associated transcription factor (MITF), an important transcription factor affecting melanogenesis, was also negatively correlated with the expression of UCA1. Furthermore, the transcription factor CRE-binding protein (CREB), which promotes MITF expression, was negatively regulated by UCA1. The cAMP/protein kinase A (PKA), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) signaling pathways, which are upstream of the CREB/MITF/melanogenesis axis, were activated or inhibited in response to silencing or enhancing UCA1 expression, respectively. In addition, enhanced UCA1 expression downregulates the expression of melanogenesis-related genes induced by UVB in melanocytes. In conclusion, UCA1 may negatively regulate the CREB/MITF/melanogenesis axis through inhibiting the cAMP/PKA, ERK, and JNK signaling pathways in melanocytes. UCA1 may be a potential therapeutic target for the treatment of pigmented skin diseases.

MicroRNA-143-5p targeting eEF2 gene mediates intervertebral disc degeneration through the AMPK signaling pathway

Background

Intervertebral disc degeneration (IDD) is a major contributor to back, neck, and radicular pain, and the treatment of IDD is costly and relatively ineffective. Dysregulation of microRNAs (miRNAs) has been reported to be involved in IDD. The purpose of our study is to illustrate the potential that miR-143-5p targeting eEF2 gene mediates IDD.

Methods

Following the establishment of the IDD rat models, expression of miR-143-5p, eEF2, Bcl-2, Bax, AMPK, mTOR, cyclinD, COL2, ACAN, and DCN was detected. The NP cells isolated from degenerative intervertebral disc (IVD) were introduced with a series of mimic, inhibitor, or AICAR to explore the functional role of miR-143-5p in IDD and to characterize the relationship between miR-143-5p and eEF2. Cell viability, cell cycle, apoptosis, and senescence were also evaluated.

Results

A reduction in eEF2, an increase in miR-143-5p, and activation of the AMPK signaling pathway were observed in degenerative IVD. Moreover, increased senescent NP cells were observed in degenerative IVD. eEF2 was confirmed as a target gene of miR-143-5p. miR-143-5p was found to activate the AMPK signaling pathway. The restoration of miR-143-5p or the activation of AMPK signaling pathway decreased COL2, ACAN, and DCN expression, coupled with the inhibition of NP cell proliferation and differentiation, and promotion of NP apoptosis and senescence. On the contrary, the inhibition of miR-143-5p led to the reversed results.

Conclusion

The results demonstrated that the inhibition of miR-143-5p may act as a suppressor for the progression of IDD.