MicroRNA-204-5p regulates 3T3-L1 preadipocyte proliferation, apoptosis and differentiation

Total saponins from Panax japonicus alleviate insulin resistance via exosomal miR204/Elovl6-mediated adipocyte-macrophage crosstalk

BACKGROUND

Insulin resistance (IR) is a key factor in the development of type 2 diabetes, and M2-like macrophages are important in maintaining normal glucose homeostasis. Our previous research has demonstrated that the total saponins from Panax japonicus (TSPJ) reduce IR in adipocytes and promote the M2 polarization of macrophages, but the molecular mechanism is unclear.

PURPOSE

In the study, we aimed to elucidate whether TSPJ mitigate IR by enhancing the intercellular communication between adipocytes and macrophages and describe how the exosomes from bone marrow-derived macrophages (BMDMs) modulate the insulin sensitivity of adipocytes via miR204.

METHODS

We used both in vitro and in vivo models to study the effects of TSPJ on IR, with a particular emphasis on the exosomes from M2-type BMDMs. Furthermore, we investigated the mechanisms by which exosomal miR204 and its downstream target Elovl6 influence IR in an obese mouse model, as well as in adipocytes with double inhibition of miR204 and Elovl6.

RESULTS

In the animal model, TSPJ significantly increased miR204 expression in BMDMs-derived exosomes and decreased the level of Elovl6 in adipocytes. However, when the C75BL/6 mice had miR204 ablation, TSPJ became less capable of enhancing insulin sensitivity, and the expressions of Irs1, Insr, and Slc2a4 in the adipose tissue decreased. In the cell model where the macrophages carried miR204 ablation and the adipocytes had Elovl6 knockdown, the expressions of IR-related genes increased in the adipocytes.

CONCLUSIONS

TSPJ mitigated IR through adipocyte-BMDM crosstalk mediated by exosomes via the miR204/Elovl6 pathway.

Start small, think big: MicroRNAs in diabetes mellitus and relevant cardiorenal-liver metabolic health spectrum

Diabetes mellitus (DM), co-existing with metabolic disorder of cardio-renal-liver, is one of the most difficult problems in medicine that attracts global concern with high mortality. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that negatively regulates gene expression and exerts active against a large proportion of the transcriptome, due to their high evolutionary conservation. Emerging evidence prove that miRNAs are involved in the pathogenesis of DM and associated metabolic disorders, manifested by their variable alteration in the blood, urine, tissues, or organs, principally contributing to modulate the interconnections between DM and cardio-renal-liver metabolism. Mechanistically, miRNAs regulate various biological processes, such as metabolism of insulin, lipid, glucose, inflammatory response, fibrosis, oxidative stress, apoptosis, and angiogenesis, etc. This review emphasizes the function of miRNAs and highlights the physiopathological regulation of miRNA in DM and related complications, especially the dysfunction of cardiovascular system, kidneys, and liver, with the aim of providing promising biomarkers for assisting early diagnosis of DM with cardio-renal-liver- specific metabolic disorders, as well as for the development of miRNA-targeting agents.

miR-129 Regulates Yak Intramuscular Preadipocyte Proliferation and Differentiation through the PI3K/AKT Pathway

miR-129 plays a crucial role in regulating various cellular processes, including adipogenesis; however, its downstream molecular mechanisms remain unclear. In this study, we demonstrated that miR-129 promotes yak adipogenesis in vitro via the PI3K/AKT pathway. Overexpression and interference of miR-129 in yak intramuscular preadipocytes (YIMAs) enhanced and inhibited cell differentiation, respectively, with corresponding changes in cell proliferation. Further investigation revealed that miR-129 enhances AKT and p-AKT activity in the AKT pathway without affecting cell apoptosis, and a specific inhibitor (LY294002) was used to confirm that miR-129 regulates YIMAs proliferation and differentiation through the PI3K/AKT pathway. Our findings suggest that miR-129 promotes yak adipogenesis by enhancing PI3K/AKT pathway activity. This study provides the foundation to precisely elucidate the molecular mechanism of miR-129 in YIMAs adipogenesis and develop advanced miRNA-based strategies to improve meat nutrition and obesity-related ailments in beef production.

Bta-miR-484 Targets SFRP1 and Affects Preadipocytes Proliferation, Differentiation, and Apoptosis

MicroRNAs (miRNAs) are essential regulators of numerous biological processes in animals, including adipogenesis. Despite the abundance of miRNAs associated with adipogenesis, their exact mechanisms of action remain largely unknown. Our study highlights the role of bta-miR-484 as a major regulator of adipocyte proliferation, apoptosis, and differentiation. Here, we demonstrated that the expression of bta-miR-484 initially increased during adipogenesis before decreasing. Overexpression of bta-miR-484 in adipocytes ultimately inhibited cell proliferation and differentiation, reduced the number of EdU fluorescence-stained cells, increased the number of G1 phase cells, reduced the number of G2 and S phase cells, and downregulated the expression of proliferation markers (CDK2 and PCNA) and differentiation markers (CEBPA, FABP4, and LPL). Additionally, overexpression of bta-miR-484 promoted the expression of apoptosis-related genes (Caspase 3, Caspase 9, and BAX), and increased the number of apoptotic cells observed via flow cytometry. In contrast, bta-miR-484 inhibition in adipocytes yielded opposite effects to those observed during bta-miR-484 overexpression. Moreover, luciferase reporter assays confirmed SFRP1 as a target gene of bta-miR-484, and revealed that bta-miR-484 downregulates SFRP1 mRNA expression. These findings offer compelling evidence that bta-miR-484 targets SFRP1, inhibits proliferation and differentiation, and promotes apoptosis. Therefore, these results offer novel insights into the bta-miR-484 regulation of adipocyte growth and development.

circITGB1 Regulates Adipocyte Proliferation and Differentiation via the miR-23a/ARRB1 Pathway

Adipose tissues represent an important energy storage organ in animals and are the largest endocrine organ. It plays an important regulatory role in the pathogenesis of insulin resistance, cardiovascular disease, and metabolic syndrome. Adipose development is a complex biological process involving multiple key genes, signaling pathways, and non-coding RNAs, including microRNAs and circular RNAs. In this study, we characterized circITGB1 and named its host gene ITGB1, which is differentially expressed in sheep of different months based on sequencing data. We collated and analyzed the sequencing data to select miRNA-23a with strong binding to ARRB1. We found that miRNA-23a regulates the development and differentiation of sheep adipocytes by targeting ARRB1. As a competing endogenous RNA, circITGB1 overexpression effectively alleviated the inhibitory effect of miR-23a on ARRB1. Conclusively, we provide evidence that circITGB1 regulates the proliferation and differentiation of sheep adipocytes via the miR-23a/ARRB1 pathway. This study provides a scientific basis for further studies on adipose tissue development at the circRNA level.

CircRNA Profiling Reveals an Abundant circBDP1 that Regulates Bovine Fat Development by Sponging miR-181b/miR-204 Targeting Sirt1/TRARG1

The proliferation and differentiation of preadipocytes is an important factor determining bovine fat development, which is closely related to the feed conversion ratio, carcass traits, and beef quality. The purpose of this study was to identify the effects of candidate circRNA and miRNA on the proliferation and differentiation of bovine preadipocytes in order to provide basic materials for molecular breeding in cattle. circRNA sequencing was performed on bovine adipocyte samples at different differentiation time points, and a total of 1830 differentially expressed circRNAs were identified. Among them, circBDP1, derived from the bovine BDP1 gene, has potential binding sites for miR-204 (known as a regulator of bovine fat development) and miR-181b, which gives us a hint that circBDP1 may regulate bovine fat development by adsorbing miR-204 and miR-181b. Here, our results revealed that circBDP1 overexpression promoted the proliferation and differentiation of bovine preadipocytes. The miRNA profile of bovine adipocytes at different differentiation time points was also analyzed using the small RNA sequencing method, and a total of 89 differentially expressed miRNAs were identified, including miR-204 and miR-181b. As expected, dual-luciferase reporter results showed that circBDP1 competitively adsorbed miR-181b and miR-204. Overexpression and interference of miR-181b in bovine preadipocytes and 3T3-L1 showed that miR-181b promoted the proliferation and differentiation of preadipocytes. Further results displayed that miR-181b and miR-204 simultaneously targeted the SIRT1 gene, and miR-204 also targeted the 3' UTR region of the TRARG1 gene. In summary, this study found that miR-181b and miR-204 were involved in fat development by targeting SIRT1 and TRARG1. The results of this study will lay a foundation for the research of fat development and beef cattle industry.

Molecular Regulation of Yak Preadipocyte Differentiation and Proliferation by LncFAM200B and ceRNA Regulatory Network Analysis

The positive regulatory role of lncFAM200B in differentiation and lipid deposition in yak intramuscular preadipocytes has been demonstrated in our previous study. However, the regulatory mechanisms remain unclear. In this study, we aimed to produce complete mRNA and microRNA (miRNA) profiles after adenovirus-mediated lncFAM200B overexpression in yak preadipocytes using high-throughput sequencing. We constructed a competing endogenous RNA (ceRNA) network with lncFAM200B as the core and identified the functions of the selected target miRNA during cell proliferation and differentiation. We obtained 118 differentially expressed genes (DEGs) after lncFAM200B overexpression, 76 of which were up-regulated, including Notch signaling members NOTCH3, DTX3L, and HES4, and 42 DEGs were down-regulated, including genes related to the cell cycle (CCNA2, BUB1, CDC20, TOP2A, and KIF20A). Additionally, many ubiquitin-mediated proteolysis pathway members were also significantly up-regulated (BUA7, PML, TRIM21, and TRIM25). MiRNA sequencing showed that 13 miRNAs were significantly up-regulated, and 12 miRNAs were down-regulated. Among them, 29 targets of 10 differentially expressed miRNAs (DEMs) were differentially expressed, including miR-152-FBXO33, miR-6529a-TRIM21, miR-148c-NOTCH3, and the miR-6529b-HES4 axis. We further verified that overexpression and inhibition of miR-6529a can inhibit and promote, respectively, the proliferation and differentiation of preadipocytes. Taken together, our study not only revealed the regulatory network of lncFAM200B during yak preadipocytes differentiation but also laid a foundation for elucidating the cause for lower intramuscular fat content in yaks at the molecular level.

Maternal Exercise Programs Glucose and Lipid Metabolism and Modulates Hepatic miRNAs in Adult Male Offspring

Detrimental exposures in mothers are recognized as risk factors for the development of metabolic dysfunction in offspring. In contrast, maternal exercise has been reported to be an effective strategy to maintain offspring health. However, the mechanisms underlying the protective effects of maternal exercise on adult offspring metabolic homeostasis are largely unclear. This study aims to investigate whether maternal exercise before and during pregnancy could combat the adverse effects of maternal high-fat diet (HFD) on metabolism in 24-week-old male offspring and to explore the role of miRNAs in mediating the effects. Female C57BL/6 mice were fed with either control diet or HFD 3-week prior to breeding and throughout pregnancy and lactation, among whom half of the HFD-fed mice were submitted to voluntary wheel running training 3-week before and during pregnancy. Male offspring were sedentary and fed with a control diet from weaning to 24 weeks. Body weight, the content of inguinal subcutaneous adipose tissue and perirenal visceral adipose tissue, glucose tolerance, and serum insulin and lipids in offspring were analyzed. Hepatic tissues were collected for transcriptome and miRNA sequencing and reverse transcription-quantitative polymerase chain reaction validation. The results showed that maternal HFD resulted in significant glucose intolerance, insulin resistance, and dyslipidemia in adult offspring, which were negated by maternal exercise. Transcriptome sequencing showed that maternal exercise reversed perinatal HFD-regulated genes in adult offspring, which were enriched in glucose and lipid metabolic-related signaling pathways. At the same time, maternal exercise significantly rescued the changes in the expression levels of 3 hepatic miRNAs in adult offspring, and their target genes were involved in the regulation of cholesterol biosynthesis and epigenetic modification, which may play an important role in mediating the intergenerational metabolic regulation of exercise. Overall, our research pioneered the role of miRNAs in mediating the programming effects of maternal exercise on adult offspring metabolism, which might provide novel insight into the prevention and treatment of metabolic disorders in early life.

HDL-enriched miR-30a-5p is associated with HDL-cholesterol levels and glucose metabolism in healthy men and women

Aim: To investigate the associations between high-density lipoprotein (HDL)-enriched miRNAs and the cardiometabolic profile of healthy men and women. Patients & methods: miRNAs were quantified using next-generation sequencing of miRNAs extracted from purified HDL and plasma from 17 healthy men and women couples. Results: Among the HDL-enriched miRNAs, miR-30a-5p correlated positively with HDL-cholesterol levels, whereas miR-144-5p and miR-30a-5p were negatively associated with fasting insulin levels and Homeostasis model assessment of insulin resistance index. Overall, miR-30a-5p, miR-150-5p and sex contributed to 45% of HDL-cholesterol variance. A model containing only miR-30a-5p, age and sex explained 41% of fasting glucose variance. Conclusion: HDL-enriched miRNAs, notably miR-30a-5p, are associated with cardiometabolic markers. These miRNAs could play a role in HDL's protective functions, particularly regarding glucose-insulin homeostasis.

Recent Update on the Molecular Mechanisms of Gonadal Steroids Action in Adipose Tissue

The gonadal steroids, including androgens, estrogens and progestogens, are involved in the control of body fat distribution in humans. Nevertheless, not only the size and localization of the fat depots depend on the sex steroids levels, but they can also highly affect the functioning of adipose tissue. Namely, the gonadocorticoids can directly influence insulin signaling, lipid metabolism, fatty acid uptake and adipokine production. They may also alter energy balance and glucose homeostasis in adipocytes in an indirect way, e.g., by changing the expression level of aquaglyceroporins. This work presents the recent advances in understanding the molecular mechanism of how the gonadal steroids influence the functioning of adipose tissue leading to a set of detrimental metabolic consequences. Special attention is given here to highlighting the sexual dimorphism of adipocyte functioning in terms of health and disease. Particularly, we discuss the molecular background of metabolic disturbances occurring in consequence of hormonal imbalance which is characteristic of some common endocrinopathies such as the polycystic ovary syndrome. From this perspective, we highlight the potential drug targets and the active substances which can be used in personalized sex-specific management of metabolic diseases, in accord with the patient's hormonal status.

MicroRNA-148a Regulates the Proliferation and Differentiation of Ovine Preadipocytes by Targeting PTEN

MicroRNAs (miRNAs) have been found to be involved in lipid deposition and metabolism. However, there have been no reports on the roles of miR-148a in the proliferation and adipogenesis of preadipocytes in sheep. In this study, the expression of miR-148a was profiled in the eight tissues of Tibetan ewes and differentiated preadipocytes, and the role of miR-148a in differentiation and proliferation of ovine preadipocytes was investigated using Oil Red O staining, CCK-8, EdU staining, cell cycle detection, and RT-qPCR. The effect of PTEN on the differentiation of ovine preadipocytes was also investigated. The miR-148a was widely expressed in the eight tissues investigated and had significantly increased expression in liver, spleen and subcutaneous adipose tissues, and the heart. The expression of miR-148a continued to increase with the differentiation of ovine preadipocytes. The over-expression of miR-148a significantly promoted differentiation but inhibited the proliferation of ovine preadipocytes. The inhibition of miR-148a had the opposite effect on the differentiation and proliferation of ovine preadipocytes with over-expressed miR-148a. The results from the dual luciferase reporter assays showed that miR-148a mimic significantly decreased the luciferase activity of PTEN-3'UTR dual luciferase reporter vector, suggesting that PTEN is a target gene of miR-148a. In over-expressed-PTEN preadipocytes, the number of lipid droplets remarkably decreased, and the expression levels of adipogenesis marker genes PPARγ, FASN, FATP4, GLUT4, C/EBPβ and LPL were also significantly down-regulated. These results suggest that miR-148a accelerated the adipogenic differentiation of ovine preadipocytes by inhibiting PTEN expression, and also inhibited the proliferation of ovine preadipocytes.

MiR-146a-5p targeting SMAD4 and TRAF6 inhibits adipogenensis through TGF-β and AKT/mTORC1 signal pathways in porcine intramuscular preadipocytes

BACKGROUND

Intramuscular fat (IMF) content is a vital parameter for assessing pork quality. Increasing evidence has shown that microRNAs (miRNAs) play an important role in regulating porcine IMF deposition. Here, a novel miRNA implicated in porcine IMF adipogenesis was found, and its effect and regulatory mechanism were further explored with respect to intramuscular preadipocyte proliferation and differentiation.

RESULTS

By porcine adipose tissue miRNA sequencing analysis, we found that miR-146a-5p is a potential regulator of porcine IMF adipogenesis. Further studies showed that miR-146a-5p mimics inhibited porcine intramuscular preadipocyte proliferation and differentiation, while the miR-146a-5p inhibitor promoted cell proliferation and adipogenic differentiation. Mechanistically, miR-146a-5p suppressed cell proliferation by directly targeting SMAD family member 4 (SMAD4) to attenuate TGF-β signaling. Moreover, miR-146a-5p inhibited the differentiation of intramuscular preadipocytes by targeting TNF receptor-associated factor 6 (TRAF6) to weaken the AKT/mTORC1 signaling downstream of the TRAF6 pathway.

CONCLUSIONS

MiR-146a-5p targets SMAD4 and TRAF6 to inhibit porcine intramuscular adipogenesis by attenuating TGF-β and AKT/mTORC1 signaling, respectively. These findings provide a novel miRNA biomarker for regulating intramuscular adipogenesis to promote pork quality.

Elucidation of the Hdac2/Sp1/miR-204-5p/Bcl-2 axis as a modulator of cochlear apoptosis via in vivo/in vitro models of acute hearing loss

We previously reported that dysregulation of histone deacetylase 2 (Hdac2) was associated with the prognosis of sudden sensorineural hearing loss. However, the underlying molecular mechanisms are poorly understood. In the present study, we developed an acute hearing loss animal model in guinea pigs by infusing lipopolysaccharides (LPS) into the cochlea and measured the expression of Hdac2 in the sensory epithelium. We observed that the level of Hdac2 was significantly decreased in the LPS-infused cochleae. The levels of apoptosis-inhibition genes Bcl-2 and Bcl-xl were also decreased in the cochlea and correlated positively with the levels of Hdac2. Caspase3 or TUNEL-positive spiral ganglion neurons, hair cells, and supporting cells were observed in the LPS-infused cochleae. These in vivo observations were recapitulated in cell culture experiments. Based on bioinformatics analysis, we found miR-204-5p was engaged in the regulation of Hdac2 on Bcl-2. Molecular mechanism experiments displayed that miR-204-5p could be regulated by Hdac2 through interacting with transcription factor Sp1. Taken together, these results indicated that the Hdac2/Sp1/miR-204-5p/Bcl-2 regulatory axis mediated apoptosis in the cochlea, providing potential insights into the progression of acute hearing loss. To our knowledge, the study describes a miRNA-related mechanism for Hdac2-mediated regulation in the cochlea for the first time.

New insights of Krüppel-like transcription factors in adipogenesis and the role of their regulatory neighbors

Obesity is a serious public health problem associated with predisposition to develop metabolic diseases. Over the past decade, several studies in vitro and in vivo have shown that the activity of Krüppel-like factors (KLFs) regulates adipogenesis, adipose tissue function and metabolism. Comprehension of both the origin and development of adipocytes and of adipose tissue could provide new insights into therapeutic strategies to contend against obesity and related metabolic diseases. This review focus on the transcriptional role that KLF family members play during adipocyte differentiation, describes their main interactions and the mechanisms involved in this fine-tuned developmental process. We also summarize new findings of the involvement of several effectors that modulate KLFs expression during adipogenesis, including growth factors, circadian clock proteins, interleukins, nuclear receptors, protein kinases and importantly, microRNAs. Thus, KLFs regulation by these factors and emerging molecules might constitute a potential therapeutic target for anti-obesity intervention.

Bioinformatics analysis of microRNA linked to ubiquitin proteasome system in traumatic osteonecrosis of the femoral head

MicroRNAs (miRNAs) have been suggested to act critical roles in the pathophysiology of traumatic osteonecrosis of the femoral head (TONFH). Unfortunately, their roles in the development of TONFH are still ambiguous. The purpose of this study is to identify promising miRNA biomarkers in traumatic osteonecrosis development.We conducted a comprehensive bioinformatics analysis using microarray datasets downloaded from the Gene Expression Omnibus database, and compared the expression of miRNAs in the serum of TONFH patients with controls. Next, we performed target prediction, function enrichment analysis, and protein-protein interaction network analysis based on differentially expressed (DE) miRNAs.We identified 26 DE miRNAs that may contribute to the pathophysiology of TONFH. The miRNAs were linked to ubiquitin proteasome system including conjugating protein ligase activity, ubiquitin-protein ligase activity and ubiquitin mediated proteolysis 5 pathway, and we exposed miR-181a-5p and miR-140-5p as promising biomarkers in TONFH.A predicting model consisting of 5 miRNAs may help discriminating high-risk patients who might develop TONFH after femur neck fracture. Among DE miRNAs, MiR-181a-5p and miR-140-5p may contribute to the development femoral head osteonecrosis after femur neck fracture via ubiquitin proteasome system.

miR-324-5p Contributes to Cell Proliferation and Apoptosis in Pancreatic Cancer by Targeting KLF3

Pancreatic cancer cells are characterized by high cell proliferation and low cell apoptosis, but the factors involved in these processes remain to be further studied. In this study, we report that miR-324-5p regulates the proliferation and apoptosis of pancreatic cancer cells through regulating the expression of Krüppel-like factor 3 (KLF3). In both pancreatic cancer tissues and cell lines, the levels of miR-324-5p are significantly increased. Inhibition of miR-324-5p represses cell proliferation but promotes cell apoptosis, whereas overexpression of miR-324-5p exerts the opposite effect. Furthermore, we identified KLF3, a factor regulating pancreatic cancer cell proliferation and apoptosis, as a new direct downstream target of miR-324-5p. Our results suggest that miR-324-5p plays an important role in pancreatic cancer cell proliferation and apoptosis via downregulating the expression of KLF3.

MicroRNA-204-5p regulates apoptosis by targeting Bcl2 in rat ovarian granulosa cells exposed to cadmium†

This study aimed to investigate whether cadmium (Cd) cytotoxicity in rat ovarian granulosa cells (OGCs) is mediated through apoptosis or autophagy and to determine the role of microRNAs (miRNAs) in Cd cytotoxicity. To test this hypothesis, rat OGCs were exposed to 0, 10, and 20 μM CdCl2 in vitro. As the Cd concentration increased, OGC apoptosis increased. In addition, Cd promoted apoptosis by decreasing the mRNA and protein expression levels of inhibition of B-cell lymphoma 2 (Bcl2). However, under our experimental conditions, no autophagic changes in rat OGCs were observed, and the mRNA and protein expression levels of the autophagic markers microtubule-associated protein 1 light chain 3 alpha (Map1lc3b) and Beclin1 (Becn1) were not changed. Microarray chip analysis, miRNA screening, and bioinformatics approaches were used to further explore the roles of apoptosis regulation-related miRNAs. In total, 19 miRNAs putatively related to Cd-induced apoptosis in rat OGCs were identified. Notably, miR-204-5p, which may target Bcl2, was identified. Then, rat OGCs were cultured in vitro and used to construct the miR-204-5p-knockdown cell line LV2-short hairpin RNA (shRNA). LV2-shRNA cells were exposed to 20 μM Cd for 12 h, and the mRNA and protein expression levels of Bcl2 were increased. Our findings suggest that Cd is cytotoxic to rat OGCs, and mitochondrial apoptosis rather than autophagy mediates Cd-induced damage to OGCs. Cd also affects apoptosis-related miRNAs, and the underlying apoptotic mechanism may involve the Bcl2 gene.

miR-324-5p promotes adipocyte differentiation and lipid droplet accumulation by targeting Krueppel-like factor 3 (KLF3)

miRNAs, a kind of noncoding small RNA, play a significant role in adipose differentiation. In this study, we explored the effect of miR-324-5p in adipose differentiation, and found that miR-324-5p could promote adipocytes differentiation and increase body weight in mice. We overexpressed miR-324-5p during adipocytes differentiation, by oil red O and bodipy staining found that lipid accumulation was increased, and the expression level of adipogenic related genes were significantly increased. And the opposite experimental results were obtained after inhibiting miR-324-5p. In vivo, we injected miR-324-5p agomiR in obese mice and found that body weight, adipocyte area, and adipogenic-related gene expression level were significantly increased but lipolytic genes were decreased. To further explore the mechanism of miR-324-5p regulation in lipid accumulation, we constructed Krueppel-like factor 3 (KLF3) 3'-untranslated region luciferase reporter vector and KLF3 pcDNA 3.1 overexpression vector, and found that miR-324-5p was able to directly target KLF3. Overall, in this study we found that miR-324-5p could promote mice preadipoytes differentiation and increase mice fat accumulation by targeting KLF3.

ALDH1A1 Inhibits Chicken Preadipocytes' Proliferation and Differentiation via the PPARγ Pathway In Vitro and In Vivo

ALDH1A1 (aldehyde dehydrogenase 1A1) is a crucial protein in retinoids’ metabolism, and the lack of ALDH1A1 inhibits the fat deposition in mice. However, whether ALDH1A1 has a similar effect on chickens’ fat-depot is still unknown. In this study, we investigate the role of ALDH1A1 in chickens’ adipogenesis. The immortalized chicken preadipocyte 1 (ICP1) cell line and chicken primary preadipocytes isolated from abdominal fat were used to perform a series of experiments in vitro to elucidate the effects of ALDH1A1. In addition, lentivirus was used to verify the results of cell experiments in vivo. The data showed that overexpression of ALDH1A1 significantly weakened the proliferation of preadipocytes and suppressed the differentiation of preadipocytes through the PPARγ pathway, and the knockdown experiments had the opposite results. Moreover, chickens injected with overexpression lentivirus had higher abdominal fat percentage, a bigger size of lipid droplets, and higher triglyceride content in abdominal fat, and chickens injected with interfering lentivirus had the opposite situation. We proved that ALDH1A1 not only inhibited the proliferation and differentiation of chickens’ preadipocytes in vitro, but also inhibited the fat-depot of chickens in vivo, which was completely opposite the function of ALDH1A1 in mice, indicating that ALDH1A1 may have a different mechanism that is still unknown.

The role and possible mechanism of long noncoding RNA PVT1 in modulating 3T3-L1 preadipocyte proliferation and differentiation

Obesity is considered as a high-risk susceptibility state for most metabolic disorders and is directly related to preadipocyte differentiation or adipogenesis. Long noncoding RNAs (lncRNAs) are the key factors which have regulatory functions on various critical physiological and biological processes. PVT1 was identified as an oncogenic lncRNA which could promote angiogenesis in gastric cancer. However, the functions and molecular pathways related to PVT1 in adipogenesis had not been clarified yet. In the current study, the purpose was to identify the effects of lncRNA PVT1 on adipogenesis and the relevant molecular processes. Quantitative real-time polymerase chain reaction (RT-qPCR) was used to quantify PVT1 expression. The mechanism for PVT1 to participate in 3T3-L1 adipogenesis was identified by lentivirus-mediated gain- and loss-of-function tests. The potential association of PVT1 with cell viability was checked by CCK-8 assay and EdU staining. The gene expression for cytokines was determined by quantitative PCR (qPCR) and western blotting. PVT1 expression level was strongly upregulated after 3T3-L1 preadipocytes differentiated. In mice, PVT1 was abundantly expressed in adipose tissue, and the obese mice had higher PVT1 expression in adipose tissue than that of nonobese mice. Predominantly, PVT1 was found inside the nuclei. Overexpressed PVT1 could promote 3T3-L1 adipocyte differentiation as proved, which was the cause for the ability to accelerate lipid accumulation, by upregulating the expression of peroxisome proliferator activated receptor gamma, CCAAT/enhancer-binding protein α, and adipocyte protein 2, while knockdown of PVT1 caused opposite effects. The RNA immunoprecipitation demonstrated the binding relationship between PVT1 and STAT3 suggesting the potential role of STAT3 in 3T3-L1 preadipocyte differentiation. Furthermore, PVT1 could promote fatty acid synthesis but inhibit fatty acid oxidation. PVT1 was positively associated with 3T3-L1 preadipocyte differentiation, which highlighted the potential of PVT1 as a therapeutic target for obesity treatment.

Silencing of microRNA-210 inhibits the progression of liver cancer and hepatitis B virus-associated liver cancer via targeting EGR3

BACKGROUND

This study was aimed to investigate the regulatory role of microRNA-210 (miRNA-210) on the progression of liver cancer and Hepatitis B virus (HBV)-associated liver cancer.

METHODS

The expression of miRNA-210 was detected in liver tissues of HBV-associated cirrhosis and liver cancer, and in HepG2 and HepG2.2.15 cells by qRT-PCR. MiRNA-210 was silenced in HepG2 and HepG2.2.15 cells by the transfection of miRNA-210 inhibitor. The cell viability and apoptosis was detected by MTT assay and Annexin V-fluorescein isothiocyanate/propidium iodide staining, respectively. The protein expression of EGR3 was detected by Western blot. The regulatory relationship between EGR3 and miRNA-210 was predicted by TargetScan and identified by Dual luciferase reporter gene assay.

RESULTS

MiRNA-210 was overexpressed in the liver tissues of HBV-associated cirrhosis and liver cancer, and in HepG2 and HepG2.2.15 cells (P < 0.05). Silencing of miRNA-210 inhibited the viability and promoted the apoptosis of HepG2 and HepG2.2.15 cells (P < 0.05). EGR3 was a target of miRNA-210, which was down-regulated in the liver tissues of HBV-associated cirrhosis and liver cancer, and in HepG2 and HepG2.2.15 cells (P < 0.05). Silencing of miRNA-210 increased the mRNA and protein expression of EGR3 (P < 0.05). Silencing of EGR3 reversed the anti-tumor effect of miRNA-210 inhibitor on HepG2 and HepG2.2.15 cells (P < 0.05).

CONCLUSIONS

Silencing of miRNA-210 inhibits the progression of liver cancer and HBV-associated liver cancer via up-regulating EGR3.

Upregulation of microRNA-204 improves insulin resistance of polycystic ovarian syndrome via inhibition of HMGB1 and the inactivation of the TLR4/NF-κB pathway

There is growing evidence of the position of microRNAs (miRs) in polycystic ovarian syndrome (PCOS), thus our objective was to discuss the impact of miR-204 on insulin resistance (IR) in PCOS by targeting highmobility group box protein 1(HMGB1)-mediated toll-like receptor 4(TLR4)/nuclear factor-kappa B (NF-κB) pathway.PCOS-IR patients and PCOS non-insulin resistance (PCOS-NIR) patients were included. The levels of serum sex hormones and related insulin were measured, the expression of miR-204, HMGB1, TLR4 and NF-κB p65 was detected, the diagnostic efficacy of miR-204 in PCOS-IR was analyzed, and the correlation between the expression of miR-204 in PCOS-IR and fasting blood glucose (FPG), fasting insulin (FINS), homeostasis model of assessment for insulin resistance index (HOMA-IR) was analyzed. Both in vitro and in vivo experiments were performed to elucidate the capabilities of miR-204 and HMGB1 in proliferation and apoptosis of PCOS-IR granulosa cells.MiR-204 was lowly expressed as well as HMGB1, TLR4 and NF-κB p65 were highly expressed in PCOS-IR patients. Follicule-stimulating hormone was downregulated, while luteinizing hormone, estrogen, progesterone, FPG, FINS and HOMA-IR were elevated in PCOS-IR. Upregulation of miR-204 and downregulation of HMGB1 could repress TLR4/NF-κB pathway activation, degraded insulin release and testosterone (T) leveland ascended ovarian coefficient, boosted cell proliferation and restrained apoptosis of granulosa cells. Overexpression of HMGB1 reverses the effect of upregulation of miR-204 on IR of PCOS.Our study presents that high expression of miR-204 or inhibition of HMGB1 can improve IR of PCOS via the inactivation of TLR4/NF-κB pathway.

The cross-talk between adipokines and miRNAs in health and obesity-mediated diseases

BACKGROUND

Multiple studies have revealed a direct correlation between obesity and the development of multiple comorbidities, including metabolic diseases, cardiovascular disorders, chronic inflammatory disease, and cancers. However, the molecular mechanism underlying the link between obesity and the progression of these diseases is not completely understood. Adipokines are factors that are secreted by adipocytes and play a key role in whole body homeostasis. Collaboratively, miRNAs are suggested to have key functions in the development of obesity and obesity-related disorders. Based on recently emerging evidence, obesity leads to the dysregulation of both adipokines and obesity-related miRNAs. In the present study, we described the correlations between obesity and its related diseases that are mediated by the mutual regulatory effects of adipokines and miRNAs.

METHODS

We reviewed current knowledge of the modulatory effects of adipokines on miRNAs activity and their relevant functions in pathological conditions and vice versa.

RESULTS

Our research reveals the ability of adipokines and miRNAs to control the expression and activity of the other class of molecules, and their effects on obesity-related diseases.

CONCLUSIONS

This study may help researchers develop a roadmap for future investigations and provide opportunities to develop new therapeutic and diagnostic methods for treating obesity-related diseases.

Identification of microRNA-21 target genes associated with hair follicle development in sheep

Aim

The target molecule regulatory function of microRNA-21 (miR-21) in multiple signalling pathways has become a main focus of genetic and pharmacological regulatory studies of various diseases. The identification of target genes for miRNA-21 in the development of hair follicles can provide new research pathways for the regulation of cell development.

Methods

In the present study, eight six-month-old ewes from Super Merino (SM) and Small Tailed Han (STH) sheep breeds were selected. Target prediction and dual-luciferase wild-type and mutant vectors were used to identify the target genes of miR-21. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and bioinformatics analysis were conducted to analyze the effects of miR-21.

Results

The results show that the expressions of CNKSR2, KLF3 and TNPO1 were downregulated by miRNA-21 at rates of 36%, 26% and 48%, respectively. Moreover, there was a significant negative correlation between the expression of miR-21 and the three target genes in sheep with two extreme phenotypes. The expression of microRNA-21in October was significantly lower than that in January and February; while the expression of CNKSR2, KLF3 and TNPO1 in October was higher than that in January and February. Conclusions: These results suggest that CNKSR2, KLF3 and TNPO1 are three newly discovered target genes of miR-21 and might be involved in the effects of miR-21 on hair follicle development.

Integrative roles of microRNAs in lipid metabolism and dyslipidemia

PURPOSE OF REVIEW

The purpose of the review is to discuss recent advances in microRNA (miRNA) regulation of lipid metabolism and highlight the importance of miRNA-mediated gene regulation in dyslipidemia and fatty liver disease. This article reviews examples of miRNAs that bridge disparate metabolic pathways in the liver. For example, we highlight miRNAs that are regulated by the sterol-sensing pathway in the liver that in turn regulate cellular or systemic cholesterol, fatty acid, and glucose levels.

RECENT FINDINGS

The most widely studied of these miRNAs are miR-33a/b; however, we recently reported that miRNAs in the miR-183/96/182 cluster are also likely regulated by hepatic cholesterol content and mediate the observed glucose-lowering effects of the bile acid sequestrant colesevelam through the sterol-sensing pathway. In addition, several other hepatic and adipose miRNAs have been recently demonstrated to be key regulators of cellular lipid synthesis, storage, and catabolism, as well as systemic lipid metabolism. Moreover, many of these miRNAs are altered in fatty liver disease and dyslipidemia.

SUMMARY

miRNAs are not just fine-tuners of lipid metabolism, but critical regulatory factors in lipid homeostasis and health. Loss of these miRNA regulatory modules very likely contributes to the underlying metabolic defects observed in lipid disorders.

Tackling Aging by Using miRNA as a Target and a Tool

miRNA is a class of short noncoding RNA that regulates gene expression at the post-transcriptional level. Evidence of age-associated changes in miRNA expression has been collected in models ranging from nematodes to humans; however, there has been little discussion of how to turn our knowledge of miRNA biology into antiaging therapy. This opinion article provides a snapshot of our current understanding of the roles of miRNA in modulating the aging process. We discuss major chemical techniques for modifying the miRNA structure as well as developing delivery systems for intervention. Finally, technical needs to be met for bench-to-clinic translation of miRNA-based interventions are highlighted for future research.

MicroRNAs and other non-coding RNAs in adipose tissue and obesity: emerging roles as biomarkers and therapeutic targets

Obesity is a metabolic condition usually accompanied by insulin resistance (IR), type 2 diabetes (T2D), and dyslipidaemia, which is characterised by excessive fat accumulation and related to white adipose tissue (WAT) dysfunction. Enlargement of WAT is associated with a transcriptional alteration of coding and non-coding RNAs (ncRNAs). For many years, big efforts have focused on understanding protein-coding RNAs and their involvement in the regulation of adipocyte physiology and subsequent role in obesity. However, diverse findings have suggested that a dysfunctional adipocyte phenotype in obesity might be also dependent on specific alterations in the expression pattern of ncRNAs, such as miRNAs. The aim of this review is to update current knowledge on the physiological roles of miRNAs and other ncRNAs in adipose tissue function and their potential impact on obesity. Therefore, we examined their regulatory role on specific WAT features: adipogenesis, adipokine secretion, inflammation, glucose metabolism, lipolysis, lipogenesis, hypoxia and WAT browning. MiRNAs can be released to body fluids and can be transported (free or inside microvesicles) to other organs, where they might trigger metabolic effects in distant tissues, thus opening new possibilities to a potential use of miRNAs as biomarkers for diagnosis, prognosis, and personalisation of obesity treatment. Understanding the role of miRNAs also opens the possibility of using these molecules on individualised dietary strategies for precision weight management. MiRNAs should be envisaged as a future therapeutic approach given that miRNA levels could be modulated by synthetic molecules (f.i. miRNA mimics and inhibitors) and/or specific nutrients or bioactive compounds.

Differential expression of mRNA-miRNAs related to intramuscular fat content in the longissimus dorsi in Xinjiang brown cattle

In this study, we examined the role of mRNAs and miRNAs in variations in intramuscular fat content in the longissimus dorsi muscle in Xinjiang brown cattle. Two groups of Xinjiang brown cattle with extremely different intramuscular fat content in the longissimus dorsi were selected for combined of miRNA and mRNA analysis using an RNA-Seq. In total, 296 mRNAs and 362 miRNAs were significantly differentially expressed, including 155 newly predicted miRNAs, 275 significantly upregulated genes, 252 significantly upregulated miRNAs, 21 significantly downregulated genes and 110 significantly downregulated miRNAs. The combined miRNA and mRNA analysis identified 96 differentially expressed miRNAs and 27 differentially expressed mRNAs. In all, 47 upregulated miRNAs had a regulatory effect on 14 differentially downregulated target genes, and 49 downregulated miRNAs had a regulatory effect on 13 upregulated target genes. To verify the sequencing results, 10 differentially expressed genes (DEGs) and 10 differentially expressed miRNAs were selected for qRT-PCR. The qRT-PCR results confirmed the sequencing results. The results of this study shed light on the molecular regulation of bovine adipose tissue, which might help with the development of new strategies for improving meat quality and animal productivity in beef cattle to provide healthier meat products for consumers.