CircRNA-0100 positively regulates the differentiation of cashmere goat SHF-SCs into hair follicle lineage via sequestering miR-153-3p to heighten the KLF5 expression

N6-methyladenosine (m6A)-circHECA from secondary hair follicle of cashmere goats: identification, regulatory network and expression regulated potentially by methylation of its host gene promoter

OBJECTIVE

The objective of this study was to identify the N6-methyladenosine (m6A)- circHECA molecule in secondary hair follicles (SHFs) of cashmere goats, and generate its potential regulatory network, as well as explore the potential relationship between transcriptional pattern of m6A-circHECA and promoter methylation of its host gene (HECA).

METHODS

The validation of circHECA m6A sites was performed using methylation immunoprecipitation (Me-RIP) along with reverse transcription-quantitative polymerase chain reaction (RT-qPCR) technique. The nucleus and cytoplasm localizations of m6AcircHECA were performed using SHF stem cells of cashmere goats with RT-qPCR analysis. Based on in-silico analysis, the regulatory networks of m6A-circHECA were generated with related signal pathway enrichment. The methylation level of promoter region of m6A-circHECA host gene (HECA) was assessed by the bisulfite sequencing PCR (BSPPCR) technique.

RESULTS

The m6A-circHECA was confirmed to contain four m6A modification sites including m6A-213, m6A-297, m6A-780, and m6A-927, and it was detected mainly in cytoplasm of the SHF stem cells of cashmere goats. The integrated regulatory network analysis showed directly or indirectly complex regulatory relationships between m6A-circHECA of cashmere goats and its potential target molecules: miRNAs, mRNAs, and proteins. The regulatory network and pathway enrichment indicated that m6A-circHECA might play multiple roles in the SHF physiology process of cashmere goats through directly or indirectly interacting or regulating its potential target molecules. A higher methylation level of promoter region of HECA gene in SHFs of cashmere goats might cause the lower expression of m6A-circHECA.

CONCLUSION

The m6A-circHECA might play multiple roles in SHF physiology process of cashmere goats through miRNA mediated pathways along with directly or indirectly interaction with its target proteins. The promoter methylation of m6A-circHECA host gene (HECA) most likely was implicated in its expression inhibition in SHFs of cashmere goats.

Knockdown of miR-361-5p promotes the induced activation of SHF-stem cells through FOXM1 mediated Wnt/β-catenin pathway in cashmere goats

The inducing activation event of secondary hair follicle (SHF)-stem cells is considered a key biological process in the SHF regeneration, and the morphogenesis of cashmere fiber in cashmere goats. The miR-361-5p was essentially implicated in the induced activation of SHF-stem cells of cashmere goats, but its functional mechanisms are unclear. Here, we confirmed miR-361-5p was significantly downregulated in anagen SHF bugle of cashmere goats compared with that at telogen, and miR-361-5p expression was significantly lower in SHF-stem cells after activation than its counterpart before activation. Further, we found that miR-361-5p could negatively regulate the induced activation event of SHF-stem cells in cashmere goats. Mechanistically, through dual-luciferase reporter assays, miR-361-5p specifically bound with FOXM1 mRNA in SHF-stem cells of cashmere goats and negatively regulated the expression of FOXM1 gene. Also, through overexpression/knockdown analysis of FOXM1 gene, our results indicated that FOXM1 upregulated the expression of Wnt/β-catenin pathway related genes in SHF-stem cells. Moreover, based on TOP/FOP-flash Wnt report assays, the knockdown of miR-361-5p promotes the Wnt/β-catenin pathway activation through upregulating the FOXM1 expression in SHF-stem cells. Finally, we demonstrated that miR-361-5p negatively regulated the induced activation of SHF-stem cells through FOXM1 mediated Wnt/β-catenin pathway in cashmere goats.

miR-133a-3p and miR-145-5p co-promote goat hair follicle stem cell differentiation by regulating NANOG and SOX9 expression

OBJECTIVE

Hair follicle stem cells (HFSCs) differentiation is a critical physiological progress in skin hair follicle (HF) formation. Goat HFSCs differentiation is one of the essential processes of superior-quality brush hair (SQBH) synthesis. However, knowledge regarding the functions and roles of miR-133a-3p and miR-145-5p in differentiated goat HFSCs is limited.

METHODS

To examine the significance of chi-miR-133a-3p and chi-miR-145-5p in differentiated HFSCs, overexpression and knockdown experiments of miR-133a-3p and miR-145-5p (Mimics and Inhibitors) separately or combined were performed. NANOG, SOX9, and stem cell differentiated markers (β-catenin, C-myc, Keratin 6 [KRT6]) expression levels were detected and analyzed by using real-time quantitative polymerase chain reaction, western blotting, and immunofluorescence assays in differentiated goat HFSCs.

RESULTS

miR-133a-3p and miR-145-5p inhibit NANOG (a gene recognized in keeping and maintaining the totipotency of embryonic stem cells) expression and promote SOX9 (an important stem cell transcription factor) expression in differentiated stem cells. Functional studies showed that miR-133a-3p and miR-145-5p individually or together overexpression can facilitate goat HFSCs differentiation, whereas suppressing miR-133a-3p and miR-145-5p or both inhibiting can inhibit goat HFSCs differentiation.

CONCLUSION

These findings could more completely explain the modulatory function of miR-133a-3p and miR-145-5p in goat HFSCs growth, which also provide more understandings for further investigating goat hair follicle development.

CircERCC6 Positively Regulates the Induced Activation of SHF Stem Cells in Cashmere Goats via the miR-412-3p/BNC2 Axis in an m6A-Dependent Manner

The cashmere, a kind of nature protein fiber, is one of the main use of cashmere goats. The induced activation of secondary hair follicle (SHF) stem cells by the dermal papilla cell-derived signals is a key biological process for the morphogenesis and growth of cashmere fiber in cashmere goats. Previously, the circRNA-ERCC6 (circERCC6) was identified from cashmere goat SHFs; however, its biological significance is unclear in the SHF physiology process of cashmere goats. In this study, we found that circERCC6 exhibited significantly higher expression at anagen SHF bulge compared with the counterpart of telogen and harbored three m6A modified sites (named m6A-685, m6A-862, and m6A-995) through methylation immunoprecipitation using a real-time quantitative polymerase chain reaction (Me-RIP-qPCR) technique. The knockdown experiments of circERCC6 in SHF stem cells showed that circERCC6 positively regulates the induced activation of SHF stem cells in cashmere goats. Through a dual-luciferase reporter assay, we demonstrated that m6A-modified circERCC6 (m6A-circERCC6) sponged miR-412-3p to upregulate the expression of BNC2 mRNA in SHFstem cells. Through m6A-deficient mutant assay in circERCC6 knockdown SHF stem cells, we further showed that m6A modification within circERCC6 is required to mediate the miR-412-3p/BNC2 axis to finally promote the proper induced activation of SHF stem cells in cashmere goats.

Alternative Polyadenylation of Malic Enzyme 1 Is Essential for Accelerated Adipogenesis

Understanding the mechanism of adipogenesis is an important basis for improving meat quality traits of livestock. Alternative polyadenylation (APA) is a vital mechanism to regulate the expression of eukaryotic genes. However, how the individual APA functions in adipogenesis remains elusive. This study was intended to investigate the effect of malic enzyme 1 (ME1) APA on adipogenesis. Here, intracellular lipid droplets were stained using Oil red O. 3' RACE was used to verify APA events of the ME1 gene. Interactions between ME1 3' untranslated region (3' UTR)-APA isoforms and miRNAs, as well as differential expression of isoforms, were examined using dual-luciferase reporter and molecular experiments. The mechanism of ME1 APA on adipogenesis was explored by gain and loss of function assays. In this study, two ME1 isoforms with different 3' UTR lengths were detected during adipogenesis. Moreover, the ME1 isoform with a short 3' UTR was significantly upregulated compared with the one with a long 3' UTR. Mechanistically, only the long ME1 isoform was targeted by miR-153-3p to attenuate adipogenesis, while the short one escaped the regulation of miR-153-3p to accelerate adipogenesis. Our results reveal a novel mechanism of ME1 APA in regulating adipogenesis.

N6-Methyladenosine modification (m6A) of circRNA-ZNF638 contributes to the induced activation of SHF stem cells through miR-361-5p/Wnt5a axis in cashmere goats

OBJECTIVE

The objective of this study was to investigate the effects of N6-Methyladenosine modification-circRNA-zinc finger protein 638 (m6A-circRNA-ZNF638) on the induced activation of secondary hair follicle (SHF) stem cells with its potential mechanisms in cashmere goats.

METHODS

The m6A modification of ZNF638 was analyzed using methylation immunoprecipitation with real-time quantitative polymerase chain reaction technique in SHF stem cells. The effects of circRNA-ZNF638 on the induced activation of SHF stem cells in m6A dependence were evaluated through the overexpression of circRNA-ZNF638/its m6Adeficient mutants in circRNA-ZNF638 knockdown SHF stem cells. The competitive binding of miR-361-5p to circRNA-ZNF638/Wnt5a 3'- untranslated region was analyzed through Dual-luciferase reporter assay.

RESULTS

The m6A-circRNA-ZNF638 had significantly higher transcription at anagen SHF bulge of cashmere goats compared with that at telogen, as well as it positively regulated the induced activation of SHF-stem cells in cashmere goats. Mechanismly, m6A-circRNA-ZNF638 sponged miR-361-5p to heighten the transcriptional expression of Wnt5a gene in SHFstem cells. We further demonstrated that the internal m6A modification within circRNAZNF638 is required for mediating the miR-361-5p/Wnt5a pathway to regulate the induced activation of SHF stem cells through an introducing of m6A-deficient mutant of circRNAZNF638.

CONCLUSION

The circRNA-ZNF638 contributes the proper induced activation of SHF-stem cells in cashmere goats in m6A-dependent manner through miR-361-5p/Wnt5a axis.

CircAGK regulates high dihydrotestosterone-induced apoptosis in DPCs through the miR-3180-5p/BAX axis

The incidence of androgen alopecia (AGA), also known as seborrheic alopecia, has surged in recent years, and onset is occurring at younger ages. Dermal papilla cells (DPCs) are key to maintaining hair cycling, and apoptosis-driven processes in DPCs are closely related to hair follicle regeneration. Circular RNAs (circRNAs) are widely present in the human body and are closely related to the occurrence and development of many diseases. Currently, the biological functions of circRNAs in AGA are largely unknown. Whole-transcriptome sequencing was used to screen differential circRNA expression profiles between AGA patients and non-AGA patients. We found that hsa_circ_0002980 (circAGK) was significantly highly expressed in the AGA group. CircAGK promoted DPC apoptosis in the presence of high dihydrotestosterone (DHT) (15 nmol/L). By regulating the miR-3180-5p/BAX axis, circAGK promotes DPC apoptosis in a high DHT environment in vitro and inhibits hair growth in AGA mice in vivo, indicating that circAGK is a potential target for the clinical treatment of AGA.

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.

Construction and functional analysis of ceRNA regulatory network related to the development of secondary hair follicles in Inner Mongolia cashmere goats

Cashmere goat hair follicles are divided into primary hair follicles and secondary hair follicles. The primary hair follicles produce coarse hair, and the secondary hair follicles produce cashmere. The development of hair follicles is affected by a variety of signaling molecules and pathways. Studies have shown that non-coding RNAs are widely involved in the development of hair follicles of the goat, including small RNAs (miRNAs), long non-coding RNAs (lncRNA), and circular RNAs (circRNAs). In recent years, circRNAs, as a new type of circular closed non-coding RNAs, have attracted great attention due to their high stability. However, its regulatory effect on cashmere goat hair follicles mainly focuses on the periodic regulation of secondary hair follicles, and there is no report on the development of cashmere goat hair follicles during the fetal period. Therefore, this study was based on the circRNA, miRNA, and mRNA expression profiles obtained by whole-transcriptional sequencing of the skin tissue of the Inner Mongolia cashmere goats in the fetal period (days 45, 55, 65, and 75) and screening out the morphological changes of hair follicles at different periods. A total of 113 circRNAs related to the development of secondary hair follicles were present. According to the principle of the ceRNA regulatory network, a ceRNA regulatory network composed of 13 circRNAs, 21 miRNAs, and 110 mRNAs related to the development of secondary hair follicles was constructed. Then, qRT-PCR and Sanger sequencing identified circRNA2034, circRNA5712, circRNA888, and circRNA9127 were circRNAs. Next, the dual-luciferase reporter gene verified the targeting relationship of circRNA5712-miR-27b-3p-Dll4. In conclusion, this study constructed a ceRNA regulatory network for the development of cashmere goat secondary hair follicles, laying a foundation for the analysis of circRNAs regulating the morphogenesis and development of cashmere goat secondary hair follicles through the ceRNA mechanism.