miR-345-5p regulates adipogenesis via targeting VEGF-B

Extracellular vesicles from cyclic mice modulate liver transcriptome in estroupause mice independent of age

Extracellular vesicles (EVs) of different sizes are secreted by cells and may contain microRNAs (miRNAs) among its cargo. These miRNAs in EVs can induce changes in gene expression and function of recipient cells. In different cells EVs content can change with age and physiological state affecting tissue function. Based on this, the aim of this study was to characterize the miRNA content and role of small EVs (sEVs) from cyclic female mice in the modulation of liver transcriptome in estropausal mice. Two-month-old female mice were induced to estropause using 4-vinylcyclohexene diepoxide (VCD). At six months of age, VCD-treated mice were divided into placebo group (VCD) and sEVs treated group (VCD + sEVs), which received 10 injections at 3-day intervals of sEVs isolated from serum of donor cyclic female mice. A group of cyclic mice also received placebo injection and served as controls (CTL). sEVs injection in mice undergoing estropause had no effect on body mass, insulin sensitivity or organ weight. We observed ten miRNAs differentially regulated in serum sEVs of VCD compared to CTL mice. In the liver we observed 931 genes differentially expressed in VCD + sEVs compared to VCD mice. Interestingly, eight pathways were up-regulated in liver by VCD treatment and down-regulated by sEVs treatment, indicating that sEVs from cyclic mice can reverse changes promoted by estropause in liver. The expression of Cyp4a12a, which is male-specific, was elevated in VCD females but not normalized by sEVs treatment. Our findings indicate that miRNA content in sEVs is regulated by estropause in mice independent of age. Additionally, treatment of estropausal mice with sEVs from cyclic mice can partially reverse changes in the liver transcriptome.

EXOSOMES FROM CYCLIC MICE MODULATE LIVER TRANSCRIPTOME IN ESTROUPAUSE MICE INDEPENDENT OF AGE

Background

Exosomes are extracellular vesicles secreted by cells that contain microRNAs (miRNAs). These miRNAs can induce changes in gene expression and function of recipient cells. In different cells exosome content can change with age and physiological state affecting tissues function and health.

Aims

Therefore, the aim of this study was to characterize the miRNA content and role of exosomes from cyclic female mice in the modulation of liver transcriptome in estropausal mice.

Main Methods

Two-month-old female mice were induced to estropause using 4-vinylcyclohexene diepoxide (VCD). At six months of age VCD-treated mice were divided in control group (VCD) and exosome treated group (VCD+EXO), which received 10 injections at 3-day intervals of exosomes extracted from serum of cyclic female mice (CTL).

Key findings

Exosome injection in estropausal mice had no effect on body mass, insulin sensitivity or organ weight. We observed ten miRNAs differentially regulated in serum exosomes of VCD compared to CTL mice. In the liver we observed 931 genes differentially expressed in VCD+EXO compared to VCD mice. Interestingly, eight pathways were up-regulated in liver by VCD treatment and down-regulated by exosome treatment, indicating that exosomes from cyclic mice can reverse changes promoted by estropause in liver. Cyp4a12a expression which is male-specific was increased in VCD females and not reversed by exosome treatment.

Significance

Our findings indicate that miRNAs content in exosomes is regulated by estropause in mice independent of age. Additionally, treatment of estropausal mice with exosomes from cyclic mice can partially reverse changes in liver transcriptome.

Oral Spirochete Treponema denticola Intraoral Infection Reveals Unique miR-133a, miR-486, miR-126-3p, miR-126-5p miRNA Expression Kinetics during Periodontitis

miRNAs are major regulators of eukaryotic gene expression and host immunity, and play an important role in the inflammation-mediated pathways in periodontal disease (PD) pathogenesis. Expanding our previous observation with the global miRNA profiling using partial human mouth microbes, and lack of in vivo studies involving oral spirochete Treponema denticola-induced miRNAs, this study was designed to delineate the global miRNA expression kinetics during progression of periodontitis in mice infected with T. denticola by using NanoString nCounter® miRNA panels. All of the T. denticola-infected male and female mice at 8 and 16 weeks demonstrated bacterial colonization (100%) on the gingival surface, and an increase in alveolar bone resorption (p < 0.0001). A total of 70 miRNAs with at least 1.0-fold differential expression/regulation (DE) (26 upregulated and 44 downregulated) were identified. nCounter miRNA expression profiling identified 13 upregulated miRNAs (e.g., miR-133a, miR-378) and 25 downregulated miRNAs (e.g., miR-375, miR-34b-5p) in T. denticola-infected mouse mandibles during 8 weeks of infection, whereas 13 upregulated miRNAs (e.g., miR-486, miR-126-5p) and 19 downregulated miRNAs (miR-2135, miR-142-3p) were observed during 16 weeks of infection. One miRNA (miR-126-5p) showed significant difference between 8 and 16 weeks of infection. Interestingly, miR-126-5p has been presented as a potential biomarker in patients with periodontitis and coronary artery disease. Among the upregulated miRNAs, miR-486, miR-126-3p, miR-126-5p, miR-378a-3p, miR-22-3p, miR-151a-3p, miR-423-5p, and miR-221 were reported in human gingival plaques and saliva samples from periodontitis and with diabetes. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed various functional pathways of DE miRNAs, such as bacterial invasion of epithelial cells, Ras signaling, Fc gamma R-mediated phagocytosis, osteoclast differentiation, adherens signaling, and ubiquitin mediated proteolysis. This is the first study of DE miRNAs in mouse mandibles at different time-points of T. denticola infection; the combination of three specific miRNAs, miR-486, miR-126-3p, and miR-126-5p, may serve as an invasive biomarker of T. denticola in PD. These miRNAs may have a significant role in PD pathogenesis, and this research establishes a link between miRNA, periodontitis, and systemic diseases.

Recent Advances in Extracellular Vesicles in Amyotrophic Lateral Sclerosis and Emergent Perspectives

Amyotrophic lateral sclerosis (ALS) is a severe and incurable neurodegenerative disease characterized by the progressive death of motor neurons, leading to paralysis and death. It is a rare disease characterized by high patient-to-patient heterogeneity, which makes its study arduous and complex. Extracellular vesicles (EVs) have emerged as important players in the development of ALS. Thus, ALS phenotype-expressing cells can spread their abnormal bioactive cargo through the secretion of EVs, even in distant tissues. Importantly, owing to their nature and composition, EVs' formation and cargo can be exploited for better comprehension of this elusive disease and identification of novel biomarkers, as well as for potential therapeutic applications, such as those based on stem cell-derived exosomes. This review highlights recent advances in the identification of the role of EVs in ALS etiopathology and how EVs can be promising new therapeutic strategies.

The Role of VEGF Family in Lipid Metabolism

The vascular endothelial growth factor (VEGF) family plays a major role in tumors and ophthalmic diseases. However, increasingly more data reported its potential in regulating lipids. With its biological functions mainly expressed in lymphatic vessels, some factors in the families, like VEGF-A and VEGF-C, have been proved to regulate intestinal absorption of lipids by affecting chylous ducts. Other effects, including regulating lipoprotein lipase (LPL), endothelial lipase (EL), and recombinant syndecan 1 (SDC1), have also been confirmed. However, given the scant-related studies, further research should be conducted to examine the concrete mechanisms and provide pragmatic ways to apply them in the clinic. The VEGF family may treat dyslipidemia in specific ways that are different from common methods and concurrently contribute to the treatment of other metabolic diseases, like diabetes and obesity.

Repurposing Lenvatinib as A Potential Therapeutic Agent against Thyroid Eye Disease by Suppressing Adipogenesis in Orbital Adipose Tissues

Thyroid eye disease (TED) is the most common orbital disease in adults. Targeting expanded orbital adipose tissue (OAT) removed by surgery has therapeutic potential. However, drugs targeting OAT are unavailable because of the lack of deciphering features of OAT. Here, we aimed to investigate the mechanism underlying OAT expansion and identify a drug targeting OAT in TED. We found an increasing number of adipocytes with smaller size in TED-derived OATs as compared with controls, indicating that hyperplasia rather than hypertrophy contributed to OAT enlargement in TED. Typically smaller-sized adipocytes in TED patient-derived OATs were noted to localize surrounding vessels. RNA sequencing revealed enriched vascular endothelial growth factor receptor (VEGFR) genes in adipocytes differentiated from preadipocytes of TED-derived stromal vascular fraction (SVF). Similarly, OATs in patients with TED also expressed a higher level of VEGFR-1 and -2. We induced adipogenesis in TED-derived SVF with or without Lenvatinib, an FDA-approved small-molecule VEGFR inhibitor. Lenvatinib significantly suppressed lipid accumulation in a dose-dependent manner. In conclusion, our study revealed the potential anti-adipogenic effect of Lenvatinib on the OAT of TED-affected patients. In addition to proposing a drug for TED treatment, this study shows the therapeutic potential of anti-adipogenesis drugs targeting the VEGF pathway.

Plasma circulating microRNAs associated with obesity, body fat distribution, and fat mass: the Rotterdam Study

BACKGROUND

MicroRNAs (miRNAs) represent a class of small non-coding RNAs that regulate gene expression post-transcriptionally and are implicated in the pathogenesis of different diseases. Limited studies have investigated the association of circulating miRNAs with obesity and body fat distribution and their link to obesity-related diseases using population-based data.

METHODS

We conducted a genome-wide profile of circulating miRNAs in plasma, collected between 2002 and 2005, in 1208 participants from the population-based Rotterdam Study cohort. Obesity and body fat distribution were measured as body mass index (BMI), waist-to-hip ratio (WHR), android-fat to gynoid-fat ratio (AGR), and fat mass index (FMI) measured by anthropometrics and Dual X-ray Absorptiometry. Multivariable linear regression models were used to assess the association of 591 miRNAs well-expressed in plasma with these traits adjusted for potential covariates. We further sought for the association of identified miRNAs with cardiovascular and metabolic diseases in the Rotterdam study and previous publications.

RESULTS

Plasma levels of 65 miRNAs were associated with BMI, 40 miRNAs with WHR, 65 miRNAs with FMI, and 15 miRNAs with AGR surpassing the Bonferroni-corrected P < 8.46 × 10^-5. Of these, 12 miRNAs were significantly associated with all traits, while four miRNAs were associated only with WHR, three miRNAs only with FMI, and miR-378i was associated only with AGR. The most significant association among the overlapping miRNAs was with miR-193a-5p, which was shown to be associated with type 2 diabetes and hepatic steatosis in the Rotterdam Study. Moreover, five of the obesity-associated miRNAs and two of the body fat distribution miRNAs have been correlated previously to cardiovascular disease.

CONCLUSIONS

This study indicates that plasma levels of several miRNAs are associated with obesity and body fat distribution which could help to better understand the underlying mechanisms and may have the biomarker potential for obesity-related diseases.

VEGFB Promotes Myoblasts Proliferation and Differentiation through VEGFR1-PI3K/Akt Signaling Pathway

It has been demonstrated that vascular endothelial growth factor B (VEGFB) plays a vital role in regulating vascular biological function. However, the role of VEGFB in regulating skeletal muscle cell proliferation and differentiation remains unclear. Thus, this study aimed to investigate the effects of VEGFB on C2C12 myoblast proliferation and differentiation and to explore the underlying mechanism. For proliferation, VEGFB significantly promoted the proliferation of C2C12 myoblasts with the upregulating expression of cyclin D1 and PCNA. Meanwhile, VEGFB enhanced vascular endothelial growth factor receptor 1 (VEGFR1) expression and activated the PI3K/Akt signaling pathway in a VEGFR1-dependent manner. In addition, the knockdown of VEGFR1 and inhibition of PI3K/Akt totally abolished the promotion of C2C12 proliferation induced by VEGFB, suggesting that VEGFB promoted C2C12 myoblast proliferation through the VEGFR1-PI3K/Akt signaling pathway. Regarding differentiation, VEGFB significantly stimulated the differentiation of C2C12 myoblasts via VEGFR, with elevated expressions of MyoG and MyHC. Furthermore, the knockdown of VEGFR1 rather than NRP1 eliminated the VEGFB-stimulated C2C12 differentiation. Moreover, VEGFB activated the PI3K/Akt/mTOR signaling pathway in a VEGFR1-dependent manner. However, the inhibition of PI3K/Akt/mTOR blocked the promotion of C2C12 myoblasts differentiation induced by VEGFB, indicating the involvement of the PI3K/Akt pathway. To conclude, these findings showed that VEGFB promoted C2C12 myoblast proliferation and differentiation via the VEGFR1-PI3K/Akt signaling pathway, providing new insights into the regulation of skeletal muscle development.

Human milk extracellular vesicle miRNA expression and associations with maternal characteristics in a population-based cohort from the Faroe Islands

Human milk plays a critical role in infant development and health, particularly in cognitive, immune, and cardiometabolic functions. Milk contains extracellular vesicles (EVs) that can transport biologically relevant cargo from mother to infant, including microRNAs (miRNAs). We aimed to characterize milk EV-miRNA profiles in a human population cohort, assess potential pathways and ontology, and investigate associations with maternal characteristics. We conducted the first study to describe the EV miRNA profile of human milk in 364 mothers from a population-based mother-infant cohort in the Faroe Islands using small RNA sequencing. We detected 1523 miRNAs with ≥ one read in 70% of samples. Using hierarchical clustering, we determined five EV-miRNA clusters, the top three consisting of 15, 27 and 67 miRNAs. Correlation coefficients indicated that the expression of many miRNAs within the top three clusters was highly correlated. Top-cluster human milk EV-miRNAs were involved in pathways enriched for the endocrine system, cellular community, neurodevelopment, and cancers. miRNA expression was associated with time to milk collection post-delivery, maternal body mass index, and maternal smoking, but not maternal parity. Future studies investigating determinants of human EV-miRNAs and associated health outcomes are needed to elucidate the role of human milk EV-miRNAs in health and disease.